US20090119940A1 - Magnetic caliper with reference scale on edge - Google Patents
Magnetic caliper with reference scale on edge Download PDFInfo
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- US20090119940A1 US20090119940A1 US11/937,427 US93742707A US2009119940A1 US 20090119940 A1 US20090119940 A1 US 20090119940A1 US 93742707 A US93742707 A US 93742707A US 2009119940 A1 US2009119940 A1 US 2009119940A1
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- caliper
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B3/00—Measuring instruments characterised by the use of mechanical techniques
- G01B3/20—Slide gauges
- G01B3/205—Slide gauges provided with a counter for digital indication of the measured dimension
Definitions
- the invention relates generally to metrology systems, and more particularly to electronically sensing movement or position between two members such as the moving parts of a caliper.
- FIG. 8 is a diagram of a second exemplary embodiment of the slider assembly of FIG. 1 including the magnetic sensor assembly of FIG. 7 ;
- the electronic assembly 152 is attached to the slider assembly 120 , such that they move as a unit.
- the bottom surface of the signal processing and display circuit board 154 is mounted to abut the top surfaces of the slider 138 on either side of the scale member 102 .
- the magnetic sensor assembly 158 is connected to the readhead signal processing circuit 160 by connecting an array of connection pads on the connector end 232 to the connector pad array 162 on the signal processing and display circuit board 154 .
- the connector end 232 may be routed through a resilient seal (not shown) that is compressed between the cover 136 and the signal processing and display circuit board 154 , such that the electronic assembly 152 is completely sealed against contamination.
- the magnetic sensor assembly 158 is mounted in the slider 138 to sense the scale track 143 along the reference edge surface 142 of the scale member 102 , as described in greater detail below with reference to FIG. 5 .
- the flexible connector 220 has a first end 222 which includes a connector pad array 226 , which couples to the connector pad array 216 on the readhead sensing element head 210 .
- the flexible connector 220 also has a second end 232 which includes an array of connector pads 236 which couple to a connector pad array 162 on the signal processing and display circuit board 154 of FIG. 1 .
- the sensing element array 214 is responsive to magnetic field modulating elements of the scale track 143 and transmits measurement signals through the flexible connector 220 to the readhead signal processing circuit 160 on the signal processing and display circuit board 154 .
- FIG. 3 is a diagram of the sensing element head 210 of the magnetic sensor assembly 158 of FIG. 2 .
- the sensing element head 210 includes the sensing element array 214 and a connector pad array 216 which are disposed on a substrate 212 .
- the sensing element array 214 includes individual sensing elements 320 while the connector pad array 216 includes individual connector pads 330 .
- the individual sensing elements 320 are connected to the individual connector pads 330 by a series of wires (e.g., circuit traces.) More specifically, a first individual sensing element 320 is shown to be coupled to two individual connector pads 330 by wires 322 and 324 , respectively.
- the individual sensing elements 320 may be arranged in sensing pattern cells that each consist of one or more sensing elements 320 , and the pattern cells may be periodically spaced along the measuring axis direction (the x axis) at a sensing pattern pitch Pp, which may depend on a spatial wavelength or pitch P T of the scale track 143 .
- Pp may depend on a spatial wavelength or pitch P T of the scale track 143 .
- Pp N*P T , where N is a small integer (e.g., 1, 2, 3, etc.).
- a sensing pattern cell consists of two sensing elements 320 arranged at an intra-cell pitch of Pc.
- the individual sensing elements 320 are responsive to magnetic field modulating elements arranged along the scale track 143 , as described in more detail below with respect to FIG. 6 .
- the scale track 143 may include modulations in the permeability of a magnetically soft ferromagnetic material.
- the magnetic sensing elements 320 may comprise of inductors whose impedance is altered depending on their proximity to the permeability modulations along the reference scale 143 .
- the magnetic sensing elements 320 may comprise a small magnetic circuit that is perturbed by the permeability modulations along the scale track 143 .
- the magnetic sensing elements 320 may include elements that are driven to generate a local magnetic field which is coupled to and modulated by the permeability modulations along the scale track 143 .
- the connector pad array 216 may have a center-to-center spacing of approximately 200 microns.
- the overall width of the substrate 212 along the x axis direction may be approximately 13 millimeters. It should be appreciated that this specific embodiment is exemplary only, and is not limiting.
Abstract
Description
- The invention relates generally to metrology systems, and more particularly to electronically sensing movement or position between two members such as the moving parts of a caliper.
- Various electronic calipers are known that use electronic position encoders. These encoders are generally based on low-power inductive, capacitive, or magnetic position sensing technology. In general, an encoder may comprise a readhead and a scale. The readhead may generally comprise a readhead sensor and readhead electronics. The readhead outputs signals that vary as a function of the position of the readhead sensor relative to the scale, along a measuring axis. In an electronic caliper the scale is generally affixed to an elongated scale member that includes a first measuring jaw and the readhead is affixed to a slide which is movable along the scale member and which includes a second measuring jaw. Thus, measurements of the distance between the two measuring jaws may be determined based on the signals from the readhead.
- Compact electronic hand tool type calipers, (e.g., those having a measurement range on the order of 100-250 mm) have evolved to have a relatively standardized configuration including a refined set of dimensions and ergonomics, as well as extremely low power consumption. Hand tool type calipers that are even slightly larger or heavier than the standardized configuration are generally rejected in the marketplace. In conventional calipers, the elongated scale member typically has a relatively wide top surface and relatively narrow edges. The encoder scale is affixed to the top surface and the readhead is affixed to a surface of the movable slide such that it moves along the top surface over the scale. An appropriate operating gap is provided between the readhead sensor and the scale. Among other advantages, this configuration allows the readhead to be collocated with the display and the other electronic components of the caliper, which is economical. This configuration also allows the use of a relatively large sensing region between the readhead sensor and scale. This is beneficial because the S/N ratio of the types of position encoders used in electronic calipers and typically benefits from increasing the sensing region dimensions for a given operating gap. Thus, this has been the conventional configuration. For example, U.S. Pat. Nos. 6,229,301; 6,724,186; 6,332,278; RE37,490; 5,973,494; and 5,574,381, each of which is hereby incorporated by reference in its entirety, show calipers conforming to this configuration.
- U.S. Pat. No. 5,029,402, discloses a slightly different configuration used in an unconventional large caliper-type sliding gauge, which is described as being usable for measuring large objects such as tree trunks, etc. The sliding gauge includes a rod and a slide. The rod is disclosed as having eight sides. The rod includes markings that may be sensed by a length sensor on the slide. FIG. 6 of the '402 patent shows various surfaces where markings and length sensors may be applied, separated by an appropriate operating gap. In some embodiments, the widest surfaces of the rod are not used. However, the disclosure of '402 patent discloses a “caliper” that is not compact, and furthermore offers no clear advantages over the conventional caliper configuration outlined above, for conventional hand tool type caliper applications.
- It would be desirable to advance the state of the art of compact hand tool type electronic calipers, and certain related compact “jawless” calipers that comprise similar or identical components used as low cost linear scales. For example, it would be desirable to further lower the cost of electronic calipers, and/or make them more reliable.
- This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
- The present invention is directed to an improved caliper configuration that provides certain cost and/or reliability advantages, and that enables the use of readhead and scale elements that have not been practical to use in known hand tool type caliper configurations. A caliper utilizing a high resolution magnetic scale track positioned along a reference edge of a scale member is provided.
- In accordance with one aspect of the invention, the scale track may be located along an edge surface of the scale member that forms a sliding bearing with a mating surface of the caliper slide, thereby maintaining proper alignment of the slide jaw. Such an edge surface is therefore denoted a reference edge (also called a reference edge surface). In contrast, in known caliper configurations the scale track has been placed on the broad top surface of the scale member. Placing the scale track along the reference edge is advantageous in that the reference edge surface is inherently precisely machined. This is because the reference edge must guide the slide such that the measuring jaws of the caliper remain precisely parallel, to prevent measurement errors. Thus, the reference edge surface and the mating surface of the slide are inherently straight, smooth and flat. In addition, when the two surfaces slide against each other particles are excluded by the inherently close fit and the wiping action.
- In accordance with another aspect of the invention, the readhead sensor may be mounted within the slide surface that mates to the reference edge. Thus, the readhead sensor may be reliably positioned at an extremely small gap relative to the scale, in a manner that is unprecedented in a hand tool type caliper configuration. Such a small gap allows an extremely small sensor to provide good signal strength and a high signal-to-noise ratio.
- In a caliper, a loading edge (also called a loading edge surface) is located on the opposite side of the scale member from the reference edge surface. Typically, adjustment screws press a loading member against the loading edge to adjust the slide pressure and friction on the edge surfaces of the scale member. In accordance with another aspect of the invention, in some embodiments, the scale track may be located along the loading edge. In some embodiments, scale tracks may be located on both the loading edge and the reference edge. In general, for any readhead and scale configuration that is indicated as being positioned along the reference edge herein, in an alternative embodiment an analogous readhead and scale configuration may be positioned along the loading edge.
- In accordance with another aspect of the invention, the extremely small gap between the readhead sensor and the scale track allow the use of previously-impractical miniature sensor technologies, such as miniature magnetic field sensors that require a close proximity between a magnetic scale and the sensor due to spacing loss.
- In accordance with another aspect of the invention, in one embodiment the edge surface of the scale member may be used for a high resolution scale track, and the broad top surface of the scale member is used for a coarser resolution absolute position indicating scale track that is read by a known type of absolute position readhead.
- In accordance with another aspect of the invention, in one embodiment the magnetic scale track information along the reference edge (may be included in a ferromagnetically soft material that is coated, painted, sputtered, embedded, or inlaid, wherein the presence, absence, or concentration of the material spatially delineates the scale information. In some embodiments, magnetically inert material can fill voids between magnetic materials along the edge. In some embodiments, the entire edge can be coated by a protective overcoat. The scale may be formed and detected as a change in the magnetic permeability along the length of the reference (or loading) edge in such embodiments.
- In accordance with another aspect of the invention, in another embodiment, a magnetic coating can be uniformly painted, coated, inlaid, or sputtered along the reference edge, using a hard magnetic substance that is magnetizable. In one implementation, information may be written into such a material, where the magnetization direction and/or magnitude varies spatially and is detected by a readhead sensor which detects the field. Alternatively, in another embodiment, the scale member reference edge itself may be fabricated completely out of such a magnetizable material, for example a special hard ferromagnetic alloy, or a hard ferromagnetic ferrite ceramic or glass. In some embodiments, the reference edge may be protected by a protective coating, regardless of its composition.
- According to this invention, a very small readhead sensor may be reliably positioned at an extremely small gap relative to the scale track in a protected operating environment, without detrimentally affecting cost, slider friction, or signal strength. High resolution digital signals may be provided from the readhead sensor, eliminating the need for analog signal interpolation in order to provide typical caliper measurement resolution.
- The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
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FIG. 1 is a diagram of a first exemplary embodiment of a hand tool type caliper including a magnetic sensor assembly and scale track along the reference edge surface of the scale member in accordance with the present invention; -
FIG. 2 is a diagram of a first exemplary embodiment of a magnetic sensor assembly usable in the caliper ofFIG. 1 ; -
FIG. 3 is a diagram of a first exemplary embodiment of the sensing element head of the magnetic sensor assembly ofFIG. 2 ; -
FIG. 4 is a diagram of a first exemplary embodiment of the magnetic field sensing elements of the sensing element head ofFIG. 3 ; -
FIG. 5 is a diagram of a first exemplary embodiment of the slider assembly ofFIG. 1 including the magnetic sensor assembly ofFIGS. 2-4 ; -
FIG. 6 is a diagram of a portion of the scale member ofFIG. 1 including a scale track with scale elements arranged in a first exemplary pattern according to a scale pitch, for use with the magnetic sensor assembly ofFIGS. 2-5 ; -
FIG. 7 is a diagram of a second exemplary embodiment of a magnetic sensor assembly usable in the caliper ofFIG. 1 ; -
FIG. 8 is a diagram of a second exemplary embodiment of the slider assembly ofFIG. 1 including the magnetic sensor assembly ofFIG. 7 ; -
FIG. 9 is a diagram of a portion of the scale member ofFIG. 1 including a scale track with scale elements arranged in a second exemplary pattern according to a scale pitch, for use with the magnetic sensor assembly ofFIGS. 7 and 8 ; -
FIG. 10 is a diagram of a third exemplary embodiment of a magnetic sensor assembly usable in the caliper ofFIG. 1 ; -
FIG. 11 a diagram of a third exemplary embodiment of the slider assembly ofFIG. 1 including the magnetic sensor assembly ofFIG. 10 ; and -
FIG. 12 is a diagram of a portion of the scale member ofFIG. 1 including a scale track with scale elements arranged in a third exemplary pattern having a scale pitch, for use with the magnetic sensor assembly ofFIGS. 10 and 11 . -
FIG. 1 is an exploded view diagram of a first exemplary embodiment of a handtool type caliper 100 including amagnetic sensor assembly 158 andscale track 143 positioned along thereference edge surface 142 of anelongated scale member 102 in accordance with the present invention. Themagnetic sensor assembly 158 is positioned in aslider 138 to form aslider assembly 120, to which anelectronic assembly 152 is attached. A portion of theslider 138 is shown in wireform outline, to better illustrate themagnetic sensor assembly 158. The general mechanical structure and physical operation of thecaliper 100 is similar to that of certain prior electronic calipers, such as that of U.S. Pat. No. 5,901,458, which is hereby incorporated by reference in its entirety. Thescale member 102 is a rigid or semi-rigid bar having a generally rectangular cross section. In some embodiments, agroove 106 may be formed in its wide upper surface to accept an elongated thin substrate (not shown). The elongated thin substrate may be rigidly bonded in thegroove 106, and may include visual length indications and/or absolute position scale elements that cooperate with corresponding absolute readhead elements (not shown) included inelectronic assembly 152, in a manner similar to that used in known electronic calipers and as described in previously incorporated RE37,490 and U.S. Pat. No. 6,400,138, which is incorporated herein by reference in its entirety. The thin substrate may fill thegroove 106, with its top surface coplanar with the top edges ofscale member 102. - A pair of
jaws first end 112 of thescale member 102. A corresponding pair ofjaws slider 138. The outside dimensions of a workpiece are measured by placing the workpiece between a pair ofengagement surfaces 114 of thejaws engagement surfaces 122 of thejaws caliper 100 may be indicated as zero. - The measured dimension may be displayed on a
digital display 134, which is mounted within acover 136 of anelectronic assembly 152 of thecaliper 100. Theelectronic assembly 152 may also include a set of push button switches 130, 131 and 132 (e.g., an on/off switch, mode switch, and zero set switch), and a signal processing anddisplay circuit board 154 comprising a readheadsignal processing circuit 160. - As shown in
FIG. 1 , theslider assembly 120 includes aslider 138 and provides a reference edge interface configuration and a loading edge interface configuration. In various embodiments, the reference edge interface configuration includes aninternal reference surface 140 of theslider 138, and the loading edge interface configuration includes aninternal loading surface 144 of the slider 138 (also shown inFIG. 5 ). In the embodiment shown inFIG. 1 , the reference edge interface configuration also includes themagnetic sensor assembly 158, and the loading edge interface configuration also includes theloading member 148, and adjustment screws 149B. - In operation, the
slider 138 straddles thescale member 102, theinternal reference surface 140 mates against thereference edge surface 142, and theinternal loading surface 144 opposes theloading edge surface 146 with the loading member 148 (e.g., a resilient pressure bar) compressed in between by the adjustment screws 149B, as described in greater detail below with reference toFIG. 5 . As will be described in greater detail below, in various embodiments according to this invention, at least one of thereference edge 142 and theloading edge 146 include ascale track 143 that includes periodically arranged magnetic scale elements. In the embodiment shown inFIG. 1 , thereference edge 142 includes thescale track 143. - As previously indicated, the
electronic assembly 152 is attached to theslider assembly 120, such that they move as a unit. In one embodiment, the bottom surface of the signal processing anddisplay circuit board 154 is mounted to abut the top surfaces of theslider 138 on either side of thescale member 102. Themagnetic sensor assembly 158 is connected to the readheadsignal processing circuit 160 by connecting an array of connection pads on theconnector end 232 to theconnector pad array 162 on the signal processing anddisplay circuit board 154. In some embodiments, theconnector end 232 may be routed through a resilient seal (not shown) that is compressed between thecover 136 and the signal processing anddisplay circuit board 154, such that theelectronic assembly 152 is completely sealed against contamination. In theslider assembly 120, themagnetic sensor assembly 158 is mounted in theslider 138 to sense thescale track 143 along thereference edge surface 142 of thescale member 102, as described in greater detail below with reference toFIG. 5 . - It will be appreciated that locating the
scale track 143 along the inherently precisely machinedreference edge 142 provides unexpected advantages. Thereference edge 142 is inherently precisely machined and designed to retain its integrity (clean, flat, smooth, “ding-free”) in all calipers, because thereference edge 142 must guide theinternal reference surface 140 of theslide 138 such that the engagement surfaces 114 of the caliper remain precisely parallel, to prevent measurement errors. Since theinternal reference surface 140 must slide against thereference edge 142, this inherently provides a wiping action and “zero gap” between them, which inherently excludes contaminating particles. Thus, in the novel configuration of thecaliper 100, themagnetic sensor assembly 158 is positioned in theslider 138 with miniature magnetic sensors located proximate to thescale track 143, to use this protected interface in a novel manner—to provide the extremely small, reliable, particulate-free gap relative to the scale track that is required for such a miniature magnetic sensors. It should be appreciated that while providing such a small, reliable gap ordinarily requires costly fabrication of close-tolerance features, in the configuration of thecaliper 100 such a gap is provided “for free.” Conversely, the novel use of this protected interface, to provide an extremely small, reliable, particulate-free gap at little or no additional cost, enables the use of previously-impractical miniature magnetic field sensor technologies that require a close proximity between a magnetic scale and the magnetic field sensor in order to avoid spacing loss. In the current context, spacing loss refers to the degradation of the signal from a magnetic sensor as its gap increases relative to a magnetic information track with a magnetic flux transition pitch of X along the magnetic track. It is known that the signal strength decreases approximately 55 dB*(λ/d) as the gap d increases. - It should be appreciated that prior art electronic calipers have generally located larger magnetic, capacitive, or inductive sensors proximate to a larger scale track along the wide top surface (e.g., in a groove similar to the groove 106), in order to use a large gap that was obtained with low fabrication cost, and overcome the associated “large gap” spacing loss by using a larger sensor. An unexpected drawback that occurs if it is attempted to use an additional sliding interface to facilitate a small gap along the wide top (or bottom) surface of a caliper member, is that the friction between the
slider 138 and thescale member 102 increases (e.g., the friction force may approximately double). It turns out that the associated force on the slider to overcome this addition friction is generally ergonomically unacceptable. Conversely, an unexpected advantage of the configuration of thecaliper 100 according to this invention, is that an extremely small and reliable sensing gap is provided proximate to a sliding interface that is inherently necessary to maintain the alignment of the engagement surfaces 114, which means no features are introduced which might increase the minimum required amount of friction force between of thescale member 102 and theslider assembly 120. -
FIG. 2 is a diagram of a first exemplary embodiment of themagnetic sensor assembly 158 ofFIG. 1 . As shown inFIG. 2 , themagnetic sensor assembly 158 includes asensing element head 210, aflexible connector 220, abottom assembly block 240, atop assembly block 250, a mountingmember 260, and awire spring 280. Thesensing element head 210 includes asensing element array 214 and aconnector pad array 216 which are disposed on asubstrate 212. As will be described in more detail below with respect toFIG. 3 , thesensing element array 214 may be coupled to theconnector pad array 216 by a series of wires (e.g., circuit traces.) - As shown in
FIG. 2 , theflexible connector 220 has afirst end 222 which includes aconnector pad array 226, which couples to theconnector pad array 216 on the readheadsensing element head 210. Theflexible connector 220 also has asecond end 232 which includes an array ofconnector pads 236 which couple to aconnector pad array 162 on the signal processing anddisplay circuit board 154 ofFIG. 1 . During operation, thesensing element array 214 is responsive to magnetic field modulating elements of thescale track 143 and transmits measurement signals through theflexible connector 220 to the readheadsignal processing circuit 160 on the signal processing anddisplay circuit board 154. - The
magnetic sensor assembly 158 may be assembled by compressing thesensing element head 210 andfirst end 222 of theflexible connector 220 between thebottom assembly block 240 and thetop assembly block 250. More specifically, thebottom assembly block 240 includes mountingholes top assembly block 250 includes mountingholes assembly screws blocks member 260 is also attached to the top of theassembly block 250, and includes a mountinghole 264 which receives theassembly screw 274, and aclearance hole 262 which provides clearance around theassembly screw 272. As will be described in more detail below with respect toFIG. 5 , the mountingmember 260 fixes themagnetic sensor assembly 158 relative to theslider 138 of theslider assembly 120. - The
wire spring 280 includesends holes bottom assembly block 240. Thewire spring 280 is shaped with a slight bend so as to push themagnetic sensor assembly 158 away from theslider 138 and against thereference edge 142 and/or thescale track 143 with a desired force, to insure that thesensing element array 214 is located with the desired gap (e.g., a small gap, or no gap) relative to thescale track 143. -
FIG. 3 is a diagram of thesensing element head 210 of themagnetic sensor assembly 158 ofFIG. 2 . As shown inFIG. 3 , thesensing element head 210 includes thesensing element array 214 and aconnector pad array 216 which are disposed on asubstrate 212. Thesensing element array 214 includesindividual sensing elements 320 while theconnector pad array 216 includesindividual connector pads 330. Theindividual sensing elements 320 are connected to theindividual connector pads 330 by a series of wires (e.g., circuit traces.) More specifically, a firstindividual sensing element 320 is shown to be coupled to twoindividual connector pads 330 bywires individual sensing elements 320 may be arranged in sensing pattern cells that each consist of one ormore sensing elements 320, and the pattern cells may be periodically spaced along the measuring axis direction (the x axis) at a sensing pattern pitch Pp, which may depend on a spatial wavelength or pitch PT of thescale track 143. In some embodiments, Pp=N*PT, where N is a small integer (e.g., 1, 2, 3, etc.). In the embodiment shown inFIG. 3 , a sensing pattern cell consists of two sensingelements 320 arranged at an intra-cell pitch of Pc. Theindividual sensing elements 320 are responsive to magnetic field modulating elements arranged along thescale track 143, as described in more detail below with respect toFIG. 6 . - It should be appreciated that although the
sensing element head 210 is illustrated in a single-sided embodiment, more generally a sensing element head may have sensing elements and/or connector elements fabricated on both sides of a substrate, or two single-sided substrates may be laminated together, in order to provide additional sensing elements within a given set of substrate dimensions, or to provide additional space between connector pads on each side of a two-sided sensing element head, or both. In general, any of the magnetic sensor assembly embodiments disclosed herein may be adapted to use such double-sided sensing element heads, with suitable connector modifications. -
FIG. 4 is a diagram of an exemplary embodiment of magneto-resistive magneticfield sensing elements 320′ which may be used to provide a first embodiment of thesensing elements 320 ofFIG. 3 . This first embodiment is most appropriate when magnetized hard ferromagnetic material forms the magnetic field modulating elements alongscale track 143. As shown inFIG. 4 , two of thesensing elements 320′, labeled A and B, may be disposed on anon-magnetic substrate 212′ (e.g., glass or ceramic) at an intra-cell pitch of Pc′. Each of thesensing elements 320′ includes a patterned thin magneto-resistive film 420, separated by an insulating film (not show) from an adjacent high permeabilitymagnetic film 430, which acts as a magnetic flux concentrator. The patterned magneto-resistive film 420 is shown to have two terminal ends 422 and 424, which are coupled to circuit traces (not shown), such as the circuit traces 322 and 324 ofFIG. 3 . - Due to the magneto-resistive effect, the resistance between the
ends resistive film 420 depends of the flux density provided in the adjacent high permeabilitymagnetic film 430. Thus, when asensing element 320′ is moved along themagnetic scale track 143, the resistance between the terminal ends 422 and 424 of the patterned magneto-resistive film 420 is modulated depending on the relation of thesensing element 320′ to the field modulating elements of the scale track 143 (e.g., magnetized elements or track portions). The readheadsignal processing circuit 160 may provide measurement signals based on that resistance, according to known techniques. - The high-permeability
magnetic film 430 guides the magnetic field of the field modulating elements to the magneto-resistive film 420, to enhance the associated resistance modulation effect. The end portion of the high-permeabilitymagnetic film 430 extends to the edge of thesubstrate 212′, to couple as strongly as possible to the spatially modulated magnetic field of thescale track 143. A dimension WC of the end portion along the measuring axis direction may be chosen in cooperation with a parallel dimension of the field modulating elements of thescale track 143 to provide a desired signal modulation profile as the end portion is moved past the scale elements along the measuring axis. A dimension WR of thesensing element 320′ may be wider than the dimension WC, to provide a desired size and flux sensitivity for thesensing element 320′. In the embodiment shown inFIG. 4 , when the field modulating elements of thescale track 143 are arranged according to a scale wavelength or pitch PT, the intra-cell pitch of Pc′ of the A and B sensing elements 320‘may be Pc’=(N*PT)+PT/4, which provides A and B quadrature signals from the A andB sensing elements 320′. The utility of quadrature signals is known to one skilled in the art. Various other sensing pattern cell arrangements are possible using 3 or 4 sensing elements, or more, in order to provide additional measurement signals having additional spatial phase relationships, if desired. - The
sensing element 320′ may be further understood and/or modified by reference to similar elements disclosed in U.S. Pat. No. 5,889,403, which is hereby incorporated by reference in its entirety. Other sensing pattern cell arrangements and related signal processing may be understood with reference to U.S. Pat. Nos. 5,949,051; 5,386,642; 5,036,276; 6,229,301; and 7,173,414, each of which is hereby incorporated by reference in its entirety. Thus, it will be appreciated thatFIG. 4 indicates one of many possible configurations for magneto-resistive sensors that may be used according to this invention, and is exemplary only, not limiting. - More generally, when the
scale track 143 provides modulations of magnetic field strength or direction (e.g., by spatially modulated magnetization of a hard ferromagnetic material) themagnetic sensing elements 320 may utilize effects other than the magneto-resistive effect. For example, in one embodiment, thesensing elements 320 may include special inductor elements comprising a non-linear core material, where the inductance depends on the local magnetic field surrounding the inductor elements. Field modulations along thescale track 143, may be directed to the inductor elements via a magnetic circuit formed by the pattern of an adjacent highly permeable ferromagnetic film. The varying inductance of the sensing elements may be detected as the change in impedance across their terminal ends, according to known techniques. Various configurations that can be adapted for such sensing elements are disclosed in U.S. Pat. Nos. 7,180,146; 7,038,448; and 6404192, each of which is hereby incorporated by reference in its entirety. - In some embodiments, the
scale track 143 may include modulations in the permeability of a magnetically soft ferromagnetic material. In some such embodiments, themagnetic sensing elements 320 may comprise of inductors whose impedance is altered depending on their proximity to the permeability modulations along thereference scale 143. In some such embodiments, themagnetic sensing elements 320 may comprise a small magnetic circuit that is perturbed by the permeability modulations along thescale track 143. For example, in one embodiment, themagnetic sensing elements 320 may include elements that are driven to generate a local magnetic field which is coupled to and modulated by the permeability modulations along thescale track 143. Suchmagnetic sensing elements 320 may further comprise special inductor elements similar to those outlined above, which are responsive to the modulations of the generated local magnetic field. In one configuration corresponding to such sensing elements, a sensing element comprises first and second miniature planar windings located adjacent to one another (e.g., along the edge of thesubstrate 212, within a sensor dimension WR) such that they are electrically isolated and inductively coupled. The first winding is a generator winding that is driven to generate a changing magnetic field that extends to the second winding, which is a sensing winding. The resulting signal induced in the second winding depends on the changing magnetic flux density in the coupled magnetic field, which is modulated by the permeability modulations along thescale track 143. It will be appreciated that all of the foregoing sensing element configurations benefit from the small sensing gap that is provided according to this invention. -
FIG. 5 is a diagram of theslider assembly 120 ofFIG. 1 , including theslider 138 and themagnetic sensor assembly 158 ofFIGS. 2-4 .FIG. 5 shows one exemplary reference edge interface configuration and one exemplary loading edge interface configuration in greater detail. As shown, in the reference edge interface configuration themagnetic sensor assembly 158 is mounted in a recess along theinternal reference surface 140 of theslider 138, such that thesensing element array 214 is exposed toward themagnetic scale track 143. In various embodiments, themagnetic sensor assembly 158 is mounted such that the surfaces of the assembly blocks 240 and 250 slide along thereference edge surface 142 and thesensing element array 214 is aligned along thescale track 143. Thesensing element array 214 may be assembled flush with, or at a small gap, relative to the adjacent sliding surfaces of the assembly blocks 240 and 250, to provide the desired operating gap for thesensing element array 214 relative to thescale track 143. As previously outlined with reference toFIG. 2 , a wire spring 180 (hidden inFIG. 5 ) may push themagnetic sensor assembly 158 away from theslider 138 with a desired force, to insure that the sliding surfaces of the assembly blocks 240 and 250 slide against thereference edge 142 and/or thescale track 143. A mountingscrew 578 attaches the compliant mountingmember 260 to theslider 138. The mountingmember 260 is stiff along the direction of the measuring axis and compliant along directions normal to the measuring axis direction. As shown inFIG. 5 , theinternal reference surface 140 may be configured to have a slight clearance surrounding two slidingsurface portions magnetic sensor assembly 158 and slide against thereference edge 142 during operation. Theportions slider 138 are shown in wireframe, to more clearly illustrate the slidingsurface portions holes 150 may receive screws that mount theelectronic assembly 152 to theslider assembly 120. - Opposite the
internal reference surface 140, in the loading edge interface configuration, the loading member 148 (e.g., a resilient pressure bar) is positioned between theinternal loading surface 144 of theslider 138 and theloading edge 146 of thescale member 102. Theloading member 148 includes twoholes 149 that receive the tips of adjustment screws 149B that are threaded through theholes 149A. The adjustment screws 149B are adjusted such that a sliding surface portion of theloading member 148 is forced against theloading edge 146 with a desired force, which causes the internal reference surface 140 (e.g., the slidingsurface portions reference edge 142 with approximately the same force. - As previously indicated, in some embodiments, a
magnetic scale track 143 may be provided along theloading edge 146. In one such embodiment, the loading edge interface configuration may include a loading member that is “split” to provide separate sliding surface portions analogous to the slidingsurface portions loading member 148 may be omitted and the gap between theloading edge 146 and theinternal loading surface 144 may be set to a practical minimum (e.g., approximately 50 microns). The tips of adjustment screws 149B that are threaded through theholes 149A may be flat and/or may include anti-ware and/or anti-friction materials and may be adjusted to slide against theloading edge 146, to provide separate sliding surface portions analogous to the slidingsurface portions magnetic sensor assembly 158 may be mounted in a recess in theinternal loading surface 144 of theslider 138, in a configuration that is approximately a “mirror image” of the configuration shown inFIG. 5 , such that thesensing element array 214 is positioned at a small operating gap along themagnetic scale track 143 provided on theloading edge 146, straddled by sliding surface portions that govern and protect the operating gap according to design principles outlined above. -
FIG. 6 is a diagram of a portion of thescale member 102 ofFIG. 1 , includingscale elements 612 arranged along thescale track 143 according to a first exemplary scale pattern 643. The scale pattern 643 is usable with themagnetic sensor assembly 158 ofFIGS. 2-5 . As shown inFIG. 6 , thescale elements 612 are arranged according to a scale pitch PT, and are coextensive with the scale track width HT orthogonal to the measuring axis direction, which may be less than the dimension HRE of thenarrow reference edge 142. Eachscale element 612 may have a dimension of approximately PT/2 along the measuring axis direction. - In some embodiments, the scale track pattern 643 is formed as magnetized pattern in a hard ferromagnetic material formed along the
reference edge 142. In such embodiments, the magneto-resistive sensing elements 320′ or the alternative outlined above with reference toFIG. 4 may be used in themagnetic sensor assembly 158. In such embodiments, it is desirable that the material be hard magnetically with a large remanence. In one implementation, the material can be formed from a coating of a variety of potential materials (e.g., resin and ferrites, resin and metal powder, electroplated alloys, sputtered alloys similar to those used in the magnetic hard disk industry, sputtered materials such as used for magneto-optic data recording, etc.) Alternatively, the material may be inlaid or formed in a shallow scale track groove along thereference edge surface 142. Alternatively, in some embodiments, thereference member 102 may be formed of a suitable magnetizable material. In any case, the scale track material is chosen with careful consideration of tradeoffs between the design of thesensing elements 320, achievable signal strength and scale pitch PT, and other considerations are similar to those related to magnetic data storage technology. In one embodiment, the magnetic scale track pattern 643 may be written into the scale track material using an appropriate inductive write head. In another embodiment, thescale track 143 may initially be uniformly magnetized in one direction and subsequently the magnetic scale track pattern 643 may be written by locally heating the scale track material (e.g., with a laser) to a temperature just above its Curie temperature, whereupon it is cooled in a field of opposite polarity to the initial uniform magnetization direction. More generally, any suitable known magnetic information writing technique may be used. In some embodiments, it is desirable that the scale track material and pattern writing technique are able to provide a scale track pitch PT on the order of at most 20 microns, or 10 microns, or less. In such embodiments, it may be possible to provide a desired measurement resolution that is suitable for hand tool type calipers with little or no signal interpolation. Of course, in other embodiments, coarser measurement resolution may be accepted, or some level of signal interpolation may be used, and the corresponding scale track pitch PT may be larger (e.g., on the order of approximately 100 microns). - In another embodiment, the scale track pattern 643 may be formed from magnetized, physically discrete, features along the
scale track 143. An example would be laser drilled or cut holes in the form of the scale track pattern 643, which are filled with materials and magnetized approximately as outlined above with reference to a uniformly coated scale track. Alternatively, a uniformly coated scale track may be processed by known techniques to remove portions of the scale track material, leaving a desired pattern of physically discrete features that are magnetized or magnetizable. - In some embodiments, the
scale elements 612 are not magnetized scale elements. In such embodiments, the scale elements do not directly provide a spatially modulated magnetic field that is sensed by the sensor elements of themagnetic sensor assembly 158. Rather, thesensor elements 320 of the of themagnetic sensor assembly 158 may be one of the “active” types outlined above as alternatives to thesensing elements 320′, and the scale track pattern 643 may comprise scale elements that provide a material variation (e.g., physically discrete regions of a particular material) that affects their operation. For example, the scale elements may comprise discrete portions of a magnetically soft ferromagnetic material that modulates the magnetic permeability along thescale track 143. In some such embodiments, themagnetic sensing elements 320 may comprise miniature field generating elements including a small magnetic circuit that is perturbed by the permeability modulations along thescale track 143. For example, suchmagnetic sensing elements 320 may include elements that are driven to generate a local magnetic field which is coupled to and modulated by the permeability modulations along thescale track 143. Suchmagnetic sensing elements 320 may further comprise special inductor elements, which are responsive to the modulations of the generated local magnetic field. In such embodiments, although the scale elements do not directly provide a spatially modulated magnetic field, they modulate the magnetic field generated within an activemagnetic sensing element 320, as it passes by. In general, known suitable materials and fabrications techniques may be used. For reasons outlined previously, in some embodiments, it is desirable that the scale track material and fabrication techniques are able to provide a scale track pitch PT on the order of at most 20 microns, or 10 microns, or less, whereas in other embodiments a larger scale track pitch PT may be used (e.g., on the order of approximately 100 microns). - It should be appreciated that although the scale track pattern 643 shows only the
scale elements 612, more generally, in some embodiments the spaces between thescale elements 612 may be comprise a plurality of “opposite polarity” or “neutral” scale elements. For example, in one some embodiments, if thescale elements 612 each comprise a region magnetized with a first magnetization polarity, then each of the spaces between them may comprise regions that have an opposite magnetization polarity that may be introduced either inherently, or intentionally, during the pattern writing process. In other embodiments, if thescale elements 612 each comprise a strongly magnetized region, then each of the spaces between them may comprise regions that are nominally “unmagnetized.” In such embodiments, certain types of sensor elements and/or their associated signal processing may be designed to provide enhanced measurement signals based on differences between thescale elements 612 relative to the regions between them. That is, the sensor elements may have a distinctive response to the regions between thescale elements 612, as well as to thescale elements 612 themselves. - In any case, the caliper configuration corresponding to the
FIGS. 5 and 6 can provide signals that may be combined to provide a robust high-resolution displacement signal (e.g., quadrature signals with a measuring resolution of at least PT/4). - With regard to specific example dimensions for the scale track pattern 643 and
sensing element head 210, in one specific embodiment the reference edge may have a dimension HRE that is at most 4000 microns (e.g., HRE=3500 microns), thescale track 143 may have a width dimension HT=1500 microns, and a scale pitch PT=20 microns, or 10 microns. In one specific embodiment, thesensing element head 210 may have 16 sensing pattern cells arranged with a sensing pattern pitch Pp=80 microns. Each sensing element may have a dimension WC=PT/2, and a dimension WR=PT. In one embodiment, at least some of the sensing pattern cells may include at least two sensing elements arranged in quadrature, with an intra-cell pitch Pc=(PT+PT/4). Theconnector pad array 216 may have a center-to-center spacing of approximately 200 microns. The overall width of thesubstrate 212 along the x axis direction may be approximately 13 millimeters. It should be appreciated that this specific embodiment is exemplary only, and is not limiting. -
FIGS. 7-12 illustrate alternative embodiments for themagnetic sensor assembly 158, theslider assembly 120, and the scale track pattern 643 on thereference edge surface 142. As will be described in more detail below, in the embodiments ofFIGS. 7-12 , the scale elements of the scale track form are arranged in multiple sub-tracks, and the sensing element head (e.g., the sensing element head 210) is oriented at an angle relative to the measuring axis direction. -
FIGS. 7 and 8 are diagrams including a second exemplary embodiment of amagnetic sensor assembly 158′ usable in place of themagnetic sensor assembly 158 shown inFIGS. 1 , 2 and 5. Briefly stated, themagnetic sensor assembly 158′ shown inFIG. 7 is similar in construction, assembly, and operation to themagnetic sensor assembly 158 ofFIG. 2 , except as otherwise described below. Similarly numbered elements may be similar or identical between themagnetic sensor assemblies 158′ and 158. As shown inFIG. 7 , themagnetic sensor assembly 158′ includes abottom assembly block 740 and atop assembly block 750. In contrast to the assembly blocks 240 and 250 ofFIG. 2 , the assembly blocks 740 and 750 ofFIG. 7 position thesensing element head 210 such that it is tilted in themagnetic sensor assembly 158′, to distribute thesensing elements 320 over a dimension approximately equal to the width dimension HT of thescale track 143, for reasons described further below. -
FIG. 8 is a diagram second exemplary embodiment of aslider assembly 120′ including themagnetic sensor assembly 158′ ofFIG. 7 . Theslider assembly 120′ is usable in place of theslider assembly 120 shown inFIGS. 1 and 5 . Briefly stated, theslider assembly 120′ shown inFIG. 7 is similar in construction, assembly, and operation to theslider assembly 120 ofFIG. 2 , except as otherwise described below. Similarly numbered elements may be similar or identical between theslider assemblies 120′ and 120. As shown inFIG. 7 , thesensing element array 214 is tilted such that itsindividual sensing elements 320 are distributed across thescale track 143 along the direction of the z axis, as well as along the x axis. Thus, thesensing elements 320 are individually aligned with respective scale elements that are arranged to form codes in a plurality of respective sub-tracks along thescale track 143, as described in more detail below with reference toFIG. 9 . -
FIG. 9 is a diagram of a portion of thescale member 102 ofFIG. 1 , includingscale elements 912 that are arranged along thescale track 143 according to a second exemplary scale pattern 943. The scale pattern 943 is usable with themagnetic sensor assembly 158′ ofFIGS. 7 and 8 . Briefly stated, thescale elements 912 in the scale pattern 943 (and the associated sensing elements 320) may be similar in fabrication and operation to scaleelements 612 in the scale pattern 643 ofFIG. 6 , except as otherwise described below. The scale pattern 943 includes a plurality ofparallel subtracks 945 within thescale track 143, with each of thesubtracks 945 includingscale element zones 944 arranged along the scale pattern 943 according to a scale pitch PT. The intersection of each subtrack 945 with each scale element zone defines a code zone. Thescale elements 912 are configured to locate their portions in some code zones, but not in others, such that themagnetic sensor assembly 158′ outputs coded sets of signals, as it is moved or positioned along the measuring axis relative to the scale pattern 943. Thus, an embodiment of thecaliper 100 corresponding to theFIGS. 7-9 can provide signals that may be combined to provide a robust high-resolution displacement signal (e.g., quadrature signals with a measuring resolution of at least PT/4), as well to a provide a unique absolute position code associated with each measurement signal period (each spatial period) of the high-resolution displacement signal. It should be appreciated that the particular arrangement of thescale elements 912 in the scale pattern 943 is just a schematic illustration representative of many alternative arrangements, and is not limiting. - It should be noted that in discussion related to
FIGS. 3 and 4 , it was suggested that a sensing pattern pitch Pp of thesensing element head 210 may be selected such that Pp=N*PT. However, when thesensing element head 210 is tilted at an tilt angle TA relative to the measuring axis as described for the configuration ofFIGS. 7-9 , then the relationship between the sensing pattern pitch Pp and scale pitch PT is more appropriately Pp*cos(TA)=N*PT. Similarly, the relationship between the intra-cell pitch of Pc′ of the A andB sensing elements 320′ shown inFIG. 4 is more appropriately Pc′*cos(TA)=(N*PT)+PT/4, in order to provide A and B quadrature signals from the A andB sensing elements 320′. - With regard to specific example dimensions for the scale track pattern 943 and
sensing element head 210, in one specific embodiment using 16sensor elements 320 and 16subtracks 945, the reference edge may have a dimension HRE that is at most 4000 microns (e.g., HRE=3500 microns), thescale track 143 may have a width dimension HT=2400 microns, with subtrack widths of 150 microns, and a scale pitch PT=20 microns, or 10 microns. In one specific embodiment, thesensing element head 210 may be tilted at an angle of approximately TA=30 degrees from x axis, and may have 16 sensing pattern cells arranged with a sensing pattern pitch Pp=300 microns. Each sensing element may have a dimension WC=PT/2, and a dimension WR=PT. In one embodiment, at least some of the sensing pattern cells may include at least two sensing elements arranged in quadrature, with an intra-cell pitch PC=(PT+PT/4). Theconnector pad array 216 may have a center-to-center spacing of approximately 200 microns. The overall width of thesubstrate 212 along the x axis direction may be approximately 13 millimeters. It should be appreciated that this specific embodiment is exemplary only, and is not limiting. -
FIG. 10 is a diagram of a third exemplary embodiment of amagnetic sensor assembly 158″ usable in place of themagnetic sensor assembly 158 shown inFIGS. 1 , 2 and 5. In themagnetic sensor assembly 158″ asensing element head 1010 is oriented orthogonal to the measuring axis direction. This configuration allows themagnetic sensor assembly 158″ to read information from ascale track 143 that includes multiple parallel sub-tracks, as described below with reference toFIG. 12 . Themagnetic sensor assembly 158″ includes thesensing element head 1010, aflexible connector 1020, anassembly block 1040, a mountingmember 1060 and awire spring 1080. Thesensing element head 1010 includes a plurality of the previously describedsensing elements 320, which form asensing element array 1014 that is connected to aconnector pad array 1016 by a series of wires, all disposed on asubstrate 1012. In thesensing element array 1014, thesensing elements 320 are generally evenly spaced such that each one will coincide with one of thesubtracks 1245 shown inFIG. 12 . Thearrays FIG. 10 , for clarity. In various embodiments thearrays FIG. 10 . - The
flexible connector 1020 has afirst end 1022 which includes aconnector pad array 1026, which is connected to theconnector pad array 1016 on the readheadsensing element head 1010. Theflexible connector 1020 also has asecond end 1032, which includes aconnector pad array 1036, which is connected to a connector pad array on the signal processing anddisplay circuit board 154 ofFIG. 1 . - The
magnetic sensor assembly 158″ may be assembled by bonding thesensing element head 1010 into the slot 1041 in theassembly block 1040, with thesensing element array 1014 located proximate to the surface of theassembly block 1040 that will slide on thereference edge 142. The mountingmember 1060 is attached to the top of theassembly block 1040, which includes a mountinghole 1064 that receives theassembly screw 1074. As shown inFIG. 11 , the mountingmember 1060 is used to fix themagnetic sensor assembly 158″ relative to theslider 138′ of theslider assembly 120″. Thewire spring 1080 includesends holes 1046 and 1048 in theassembly block 1040. Thewire spring 1080 is shaped with a slight bend so as to push themagnetic sensor assembly 158″ away from theslider 138′ and against thereference edge 142 and/or thescale track 143 with a desired force, to insure that thesensing element array 1014 is located with the desired gap (e.g., a small gap, or no gap) relative to thescale track 143. -
FIG. 11 is a diagram of a third exemplary embodiment of aslider assembly 120″ including themagnetic sensor assembly 158″ ofFIG. 10 . Theslider assembly 120″ is usable in place of theslider assembly 120 shown inFIGS. 1 and 5 . Briefly stated, theslider assembly 120″ shown inFIG. 7 is similar in construction, assembly, and operation to theslider assembly 120 ofFIG. 2 , except as otherwise described below. Similarly numbered elements may be similar or identical between theslider assemblies 120″ and 120. As shown inFIG. 11 , thesensing element array 1014 is orthogonal to the measuring axis direction such that itsindividual sensing elements 320 are distributed across thescale track 143 along the direction of the z axis. Thus, thesensing elements 320 are individually aligned with respective scale elements that are arranged to form codes in a plurality of respective sub-tracks along thescale track 143, as described in more detail below with reference toFIG. 12 . -
FIG. 12 is a diagram of a portion of thescale member 102 ofFIG. 1 , includingscale elements 1212 that are arranged along thescale track 143 according to a third exemplary scale pattern 1243. The scale pattern 1243 is usable with themagnetic sensor assembly 158″ ofFIGS. 10 and 11 . Briefly stated, thescale elements 1212 in the scale pattern 1243 (and the associated sensing elements 320) may be similar in fabrication and operation to scaleelements 612 in the scale pattern 643 ofFIG. 6 , except as otherwise described below. The scale pattern 1243 includes a plurality ofparallel subtracks 1245 within thescale track 143, with each of thesubtracks 1245 includingscale element zones 1244 arranged along the scale pattern 1243 according to a scale pitch PT. The intersection of each subtrack 1245 with each scale element zone defines a code zone. Thescale elements 1212 located in some code zones, but not in others, such that themagnetic sensor assembly 158″ outputs coded sets of signals, as it is moved or positioned along the measuring axis relative to the scale pattern 1243. Thus, an embodiment of thecaliper 100 corresponding to theFIGS. 10-12 can provide signals that may be combined to a provide a unique absolute position code associated with each spatial period, or each scale element zone, at the scale pitch PT. In the embodiment shown inFIG. 12 , subtracks 1245QA and 1245QB are configured to provide quadrature signals with a period of 2*PT, with thescale element zones 1244Q of the subtrack 1245QB offset by PT/4 along the measuring axis, relative to thescale element zones 1244. The quadrature signals of the subtracks 1245QA and 1245QB may provide a measurement resolution of PT/2. It should be appreciated that the particular arrangement of thescale elements 1212 in the scale pattern 1243 is just a schematic illustration representative of many alternative arrangements, and is not limiting. - With regard to specific example dimensions for the scale track pattern 1243 and
sensing element head 1010, in one specific embodiment using 16sensor elements 320 and 16subtracks 1245, the reference edge may have a dimension HRE=3500 microns, thescale track 143 may have a width dimension HT=2400 microns, with subtrack widths of 150 microns, and a scale pitch PT=10 microns, or 5 microns. Thesensing element head 1010 may have a center-to-center spacing of 150 microns between 16sensor elements 320 in thesensing element array 1014, and theconnector pad array 1016 may comprise 2 rows of pads with a center-to-center spacing of approximately 200 microns between the pads in each row. The overall width of thesubstrate 1012 along the z axis direction may be approximately 3.4 millimeters. It should be appreciated that this specific embodiment is exemplary only, and is not limiting. - As outlined previously, certain compact “jawless” calipers are used as low cost linear scales. Such compact jawless calipers generally comprise similar or identical components to related compact hand tool type calipers the include jaws. Such jawless calipers are characterized by similar sliding surfaces at the reference and loading edges, similar reference and loading edge dimensions, and similar measurement resolutions. Thus, although the various embodiments illustrated herein include jaws, it will be understood that such embodiments are representative of addition embodiments in which the jaws (e.g., the
jaws - While the preferred embodiment of the invention has been illustrated and described, numerous variations in the illustrated and described arrangements of features and sequences of operations will be apparent to one skilled in the art based on this disclosure. Thus, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.
Claims (23)
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Citations (32)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4077129A (en) * | 1975-12-29 | 1978-03-07 | Kabushiki Kaisha Mitutoyo Seisakusho | Portable, lightweight measuring instrument |
US4226024A (en) * | 1978-01-30 | 1980-10-07 | Gerhard Westerberg | Caliper |
US4229883A (en) * | 1978-05-04 | 1980-10-28 | Mitutoyo Mfg. Co., Ltd. | Measuring instrument with digital display |
US4612656A (en) * | 1983-02-16 | 1986-09-16 | Mitutoyo Mfg. Co., Ltd. | Digital indication type measuring apparatus |
US4686472A (en) * | 1981-04-22 | 1987-08-11 | U.S. Philips Corporation | Magnetic sensor having closely spaced and electrically parallel magnetoresistive layers of different widths |
US4703378A (en) * | 1984-03-01 | 1987-10-27 | Sony Corporation | Magnetic transducer head utilizing magnetoresistance effect |
US5029402A (en) * | 1986-12-24 | 1991-07-09 | Rene Lazecki | Sliding gauge |
US5036276A (en) * | 1989-04-05 | 1991-07-30 | Seiko Epson Corporation | Magnetic encoder with high resolution of data signal recording at reduced recording pitch |
US5383284A (en) * | 1992-11-02 | 1995-01-24 | Rsf-Elektronik Gesellschaft M.B.H. | Measuring carriage for a linear measuring system |
US5386642A (en) * | 1992-02-04 | 1995-02-07 | Dr. Johannes Heidenhain Gmbh | Position measuring instrument |
US5574381A (en) * | 1995-01-06 | 1996-11-12 | Mitutoyo Corporation | Sealed mechanical configuration for electronic calipers for reliable operation in contaminated environments |
US5889403A (en) * | 1995-03-31 | 1999-03-30 | Canon Denshi Kabushiki Kaisha | Magnetic detecting element utilizing magnetic impedance effect |
US5901458A (en) * | 1997-11-21 | 1999-05-11 | Mitutoyo Corporation | Electronic caliper using a reduced offset induced current position transducer |
US5949051A (en) * | 1996-11-01 | 1999-09-07 | Mitutoyo Corporation | Magnetic encoder using a displacement detecting circuit thereof |
US5973494A (en) * | 1996-05-13 | 1999-10-26 | Mitutoyo Corporation | Electronic caliper using a self-contained, low power inductive position transducer |
US6070132A (en) * | 1996-10-28 | 2000-05-30 | Sony Precision Technology Inc. | Position detecting apparatus |
US6191578B1 (en) * | 1997-05-09 | 2001-02-20 | Brown & Sharpe Tesa S.A. | Magnetoresistive sensor for high precision measurements of lengths and angles |
US6229301B1 (en) * | 1997-12-22 | 2001-05-08 | Brown & Sharpe Tesa Sa | Electronic circuit and method for a dimension-measuring device |
US6326780B1 (en) * | 1998-12-01 | 2001-12-04 | Visteon Global Technologies, Inc. | Magnetic field concentrator array for rotary position sensors |
US6332278B1 (en) * | 1997-05-09 | 2001-12-25 | Brown & Sharpe Tesa Sa | Portable precision electronic caliper |
US6400138B1 (en) * | 1998-12-17 | 2002-06-04 | Mitutoyo Corporation | Reduced offset high accuracy induced current absolute position transducer |
US6404192B1 (en) * | 1999-05-12 | 2002-06-11 | Asulab S.A. | Integrated planar fluxgate sensor |
US20020129508A1 (en) * | 1999-05-14 | 2002-09-19 | Peter Blattner | Arrangement for determining the relative position of two bodies that are movable in relation to each other, and process for producing such an arrangement |
US20030047009A1 (en) * | 2002-08-26 | 2003-03-13 | Webb Walter L. | Digital callipers |
US6604289B2 (en) * | 1999-11-01 | 2003-08-12 | Rusi I. Nikolov | Universal measuring scriber |
US20030159305A1 (en) * | 2001-12-17 | 2003-08-28 | Claudia Wahl | Position measuring system |
US6724186B2 (en) * | 2000-06-27 | 2004-04-20 | Brown & Sharpe Tesa Sa | Measuring device with magneto-resistive electrodes, and measuring method |
US6834439B2 (en) * | 2002-05-21 | 2004-12-28 | Mitutoyo Corporation | Measuring tool, encoder and producing method of encoder |
US7038448B2 (en) * | 2001-05-25 | 2006-05-02 | Sentron Ag | Magnetic field sensor |
US7141965B2 (en) * | 2003-11-26 | 2006-11-28 | International Business Machines Corporation | Magnetic encoder system |
US7173414B2 (en) * | 2004-10-18 | 2007-02-06 | Honeywell International Inc. | Position detection apparatus and method for linear and rotary sensing applications |
US7180146B2 (en) * | 2003-02-24 | 2007-02-20 | Commissariat Energie Atomique | Miniature magnetic field sensor |
-
2007
- 2007-11-08 US US11/937,427 patent/US7530177B1/en not_active Expired - Fee Related
Patent Citations (33)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4077129A (en) * | 1975-12-29 | 1978-03-07 | Kabushiki Kaisha Mitutoyo Seisakusho | Portable, lightweight measuring instrument |
US4226024A (en) * | 1978-01-30 | 1980-10-07 | Gerhard Westerberg | Caliper |
US4229883A (en) * | 1978-05-04 | 1980-10-28 | Mitutoyo Mfg. Co., Ltd. | Measuring instrument with digital display |
US4686472A (en) * | 1981-04-22 | 1987-08-11 | U.S. Philips Corporation | Magnetic sensor having closely spaced and electrically parallel magnetoresistive layers of different widths |
US4612656A (en) * | 1983-02-16 | 1986-09-16 | Mitutoyo Mfg. Co., Ltd. | Digital indication type measuring apparatus |
US4703378A (en) * | 1984-03-01 | 1987-10-27 | Sony Corporation | Magnetic transducer head utilizing magnetoresistance effect |
US5029402A (en) * | 1986-12-24 | 1991-07-09 | Rene Lazecki | Sliding gauge |
US5036276A (en) * | 1989-04-05 | 1991-07-30 | Seiko Epson Corporation | Magnetic encoder with high resolution of data signal recording at reduced recording pitch |
US5386642A (en) * | 1992-02-04 | 1995-02-07 | Dr. Johannes Heidenhain Gmbh | Position measuring instrument |
US5383284A (en) * | 1992-11-02 | 1995-01-24 | Rsf-Elektronik Gesellschaft M.B.H. | Measuring carriage for a linear measuring system |
US5574381A (en) * | 1995-01-06 | 1996-11-12 | Mitutoyo Corporation | Sealed mechanical configuration for electronic calipers for reliable operation in contaminated environments |
US5889403A (en) * | 1995-03-31 | 1999-03-30 | Canon Denshi Kabushiki Kaisha | Magnetic detecting element utilizing magnetic impedance effect |
US5973494A (en) * | 1996-05-13 | 1999-10-26 | Mitutoyo Corporation | Electronic caliper using a self-contained, low power inductive position transducer |
US6070132A (en) * | 1996-10-28 | 2000-05-30 | Sony Precision Technology Inc. | Position detecting apparatus |
US5949051A (en) * | 1996-11-01 | 1999-09-07 | Mitutoyo Corporation | Magnetic encoder using a displacement detecting circuit thereof |
US6191578B1 (en) * | 1997-05-09 | 2001-02-20 | Brown & Sharpe Tesa S.A. | Magnetoresistive sensor for high precision measurements of lengths and angles |
US6332278B1 (en) * | 1997-05-09 | 2001-12-25 | Brown & Sharpe Tesa Sa | Portable precision electronic caliper |
US5901458A (en) * | 1997-11-21 | 1999-05-11 | Mitutoyo Corporation | Electronic caliper using a reduced offset induced current position transducer |
USRE37490E1 (en) * | 1997-11-21 | 2002-01-01 | Mitutoyo Corporation | Electronic caliper using a reduced offset induced current position transducer |
US6229301B1 (en) * | 1997-12-22 | 2001-05-08 | Brown & Sharpe Tesa Sa | Electronic circuit and method for a dimension-measuring device |
US6326780B1 (en) * | 1998-12-01 | 2001-12-04 | Visteon Global Technologies, Inc. | Magnetic field concentrator array for rotary position sensors |
US6400138B1 (en) * | 1998-12-17 | 2002-06-04 | Mitutoyo Corporation | Reduced offset high accuracy induced current absolute position transducer |
US6404192B1 (en) * | 1999-05-12 | 2002-06-11 | Asulab S.A. | Integrated planar fluxgate sensor |
US20020129508A1 (en) * | 1999-05-14 | 2002-09-19 | Peter Blattner | Arrangement for determining the relative position of two bodies that are movable in relation to each other, and process for producing such an arrangement |
US6604289B2 (en) * | 1999-11-01 | 2003-08-12 | Rusi I. Nikolov | Universal measuring scriber |
US6724186B2 (en) * | 2000-06-27 | 2004-04-20 | Brown & Sharpe Tesa Sa | Measuring device with magneto-resistive electrodes, and measuring method |
US7038448B2 (en) * | 2001-05-25 | 2006-05-02 | Sentron Ag | Magnetic field sensor |
US20030159305A1 (en) * | 2001-12-17 | 2003-08-28 | Claudia Wahl | Position measuring system |
US6834439B2 (en) * | 2002-05-21 | 2004-12-28 | Mitutoyo Corporation | Measuring tool, encoder and producing method of encoder |
US20030047009A1 (en) * | 2002-08-26 | 2003-03-13 | Webb Walter L. | Digital callipers |
US7180146B2 (en) * | 2003-02-24 | 2007-02-20 | Commissariat Energie Atomique | Miniature magnetic field sensor |
US7141965B2 (en) * | 2003-11-26 | 2006-11-28 | International Business Machines Corporation | Magnetic encoder system |
US7173414B2 (en) * | 2004-10-18 | 2007-02-06 | Honeywell International Inc. | Position detection apparatus and method for linear and rotary sensing applications |
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