US2591167A - Lapping thread ring gauge - Google Patents

Description

April 1952 A. E. LANGMAID ETAL 2,591,167

LAPPING THREAD RING GAUGE Filed Sept. 25, 1948 2 SHEETSSHEET 1 41 A/ F 30 K 4 o Inventors: AlvzinE iLarzymaz'd Rabert/Lfihwm Their Alorney April 1, 1952 A. LANGMAID ET AL- LAPPING THREAD RING GAUGE 2 SHEETSSHEET 2 Filed Sept. 23, 1948 Inventors:

AZvirvfilLan/gm/mid Patented Apr. 1, 1952 LAPPING THREAD RING GAUGE Alvin E. Langmaid, Bloomfield, and Robert A. Bloom, Hartford, Conn.

Application September 23, 1948, Serial No. 50,812

9 Claims. (Cl. 51 -32) This invention relates to ring gauges of the type employed for testing threads of screws to determine, their accuracy to the degree of perfection demanded by modern refinements of interchangeability.

The primary object is to provide means whereby thread forms may be produced in certain gauge parts of extremely hard material by lapping operations only. I

'With this and other objects in view which will become apparent in the following disclosure, the invention consists of mechanism including a novel form and arrangement of parts which are fully explained in said disclosure and illustrated in the accompanying drawings while the scope of the invention is defined by the appended claims.

In the drawings,

Figure 1 is a view of a ring gauge constructed in accordance with the invention.

Figure 2 is a sectional view on line 22 of Fi 1.

Figure 3 is a longitudinal sectional view of a holder and associated parts employed for a lapping operation.

Figure 4 is a left end view of the assembly shown in Fig. 3.

Figure 5 is a view similar to Fig. 4 but with a cover plate removed.

Figure 6 is an enlarged detail view of certain assembled parts shown in Fig. 5.

Figure is a sectional view on line l-'I of Fig. 3.

Figure 8 is a detail view showing a method of assembling finished parts to form a thread ring gauge, and

Figures9, 10 and 11 are detail views hereinafter more fully explained.

Referring to the drawings, the thread ring gauge illustrated in Fig. 1 comprises a body member I, centrally bored at 2 to receive a plurality of suitably threaded circular ring sectors 3. These ring sectors, in blank form (see Figs. 9 and 10) are obtained with accurate and substantially identical contours by cutting a hollow cylinder (Fig. 9) into three equal parts with beveled or relieved corners as at 4 adjacent their inner peripheral surface which subsequently is helically grooved to form threads by a lapping operation. Each ring sector 3 is located within the body member I, as in Figs. 1 and 2, with its outer segmental peripheral surface 5 in contact with the matching peripheral wall of bore 2 except at intermediate intervals where the wall of bore 2 is relieved to provide space areas 6 for reception of a film of solder as I which is applied to secure each ring sector rigidly in its required position.

It will be apparent that body member I may be substantially like well known forms of ring gauges such for example as that established by American Gauge Design standards. Thus also provision for adjustability of gauge diameter if desired may consist of the conventional arrangement wherein the ring gauge or body member I is parted by a slot 8 extended from the periphery of the ring to the central bore 2, while similarly, slots as 9 and It may be extended from the bore but terminated at suitably placed stop holes. II and I2 respectively. This arrangement serves to impart and distribute resiliency throughout the body of the ring member so as to permit flexing thereof as may be eiiected by screw adjusting means I3 housed in bore l4 which extends through the body member in intersecting relation to slot 8, all in accordance with standard design well known in the art.

Means will now be described for holding ring sectors 3 precisely in required relation within body member I while the securing film of solder I is applied within the relief intervals 6. For this purpose a fixture employed may comprise a base 9' having secured therein an upright threaded plug I0 and also three upright pins II. A set screw I2 serves to secure in place whatever plug as I0 may be appropriate to the particular thread form of a set of ring sectors which is to be assembled and secured in a body member I. It will be apparent that the threads on a plug I0, by suitable engagement while in a common plane with correspondingly formed threads on the ring sectors will locate the latter in their correct relative positions circumferentially of the body member. With the body member I, ring sectors 3 and plug I0 assembled as indicated, pins II are each adjusted and then secured as by respective set screws I5 with said pins in contact with body member I so that a three-point support is thereby provided which prevents accidental disarrangementof the several parts during the subsequent application of solder to make the assembly permanent.

Means for producing thread forms on the circular ring sectors 3 by a lapping operation include a hollow holder II, having at one end a nut receiving socket I8, with its outer end enlarged to form shoulder I9, and with a keyway provided at 20. At the opposite end, holder I1 is diametrically enlarged to provide for a chuck receiving socket H. To reduce weight of holder I! and to render parts therewithin visible and accessible, the peripheral wall of the holder is cut away to form openings 22.

A nut 23 seated on shoulder 19 of socket i8, is keyed to the holder IT at 24 and held therein against relative longitudinal movement by cap 25 which is screw threaded onto the holder. Engaged with nut 23 is a lead screw 25, terminating at one end in a shank 21 and provided at its opposite end with a socket 23 to receive split bushing 29 operable by screw 30 to clamp and rigidly secure in axial alignment with the lead screw 25 a lapping tool 3|. For split bushing 23 there may be substituted others with bores of difierent diameter appropriate for the respective shanks of lapping tools of such diameter as may be required.

Within the socket 2| of holder I1 is seated chuck body 32 which is provided with recess 34 r 3'! to thereby form radially extending channels as 38. In each channel 38 is movably fitted a shoe 39, and between the shoe. and peripheral wall 45 of the holder is placed a coiled spring 4|, operable to yieldably urge the shoe toward a central axis which coincides with the central axis about which the lead screw and lapping tool with respect to the holder are adapted to be rotated. Each shoe 39 is provided with a peripheral wall 42 facing 'said central axis. This wall is provided with a relief notch 43 and on opposite sides thereof with beveled corners 44 which serve to limit peripheral wall 42 to desirable bearing areas for engagement with a ring sector 3. Inserted at the innermost apex of each block 35 is a respective stop pin 45. These pins serve a purpose that will presently become apparent. As a means to hold the several chuck elements described accurately seated within chuck body 32, there may be employed a cover plate 46, slotted as at 41 to receive screws 48 and with the slots enlarged as at 59 to provide for facility in re- 'moving' the cover when the screws are slightly loosened. Serving to removably secure the chuck assembly described against longitudinal or rotative movement within its socket 2| of holder l1, set screw 53 and key pin are interposed between the chuck body and holder. Thus the chuck assembly may be removed from the holder for use independently thereof and concerning which there will follow further explanation.

The shank 21 of lead screw 26 is adapted to be held in a chuck as 52, carried by a reversibly driven spindle (not shown). With the lead screw thus driven while holder I! is held against rota tion, the latter is caused to move back and forth longitudinally of the coincident axes of the lead screw and lapping tool, which of course are suitably threaded to correspond to a pitch of thread which it is desired to have formed in a set of circular ring sectors 3. Each one of a set of sectors is placed between a respective shoe 39 and the lapping tool 3| (see Fig. 6). The sectors while in this arrangement are each urged against the lapping tool by their respective spring backed shoe; 'After a comparatively brief period of the action indicated and just described, a helical groove is formed in the ring sectors 3 by abrasive effect ofthe threaded lapping tool. When this grooveis-forrned to a-slight depth it is sufiicient to establish relative longitudinal movement between, the ring sectors and the chuck assembly as a whole, and the lapping tool, without assist- 4 ance of the leading eirect initially required and. imparted by the lead screw. In other words the chuck assembly together with the slightly grooved ring sectors held therein, may be removed from the holder I! and transferred to an automatic machine for continued application of the lapping operation which may proceed with a successive use of lapping tools of respective suitably different diameters to compensate for wear on each tool prior to the final one used. The contour of each successive tool used may also be different as may be required to produce the finally desired profile, such for example as that shown in Fig. 6. Asthe eiiect of abrasive action of the lapping tools upon the ring sectors progresses during relative rotary and longitudinal movement therebetween, the sectors are advanced by the spring urged shoes until they engage respective stop pins es. The location of these stop pins is such that when a ring sector has moved into position to engage them said sector is then sub-'- stantially concentric to the axis'of the threaded lapping tool, which signifies thatthread formation on the sector is completed to within a few thousandths of an inch of the required depth. Thus when each sector of a set being lapped has been arrested by engagement with stop pins as, it is thereby indicatedthat the lapping opera tion is substantially completed and the ring sec-' tors are in readiness for assembly with a body a member in accordance with the method of assembly as above explained. Subsequently slight further lapping is applied to the sectors in the permanently assembled gauge to impart thereto the I form or ring gauge thread employed for testing screw threads of American National form is shown in enlarged profile in Fig. 11 where it is indicated together with maximum diameter clearance space as at 53, this particular form being widely accepted practice in the manufac'-- ture of thread ring gauges. 1

ing, sintering or grinding to create thread for-ms within bores of relatively small diameter.

Having thus described our invention what we claim is:

l. Mechanism for producing siinul'taneouslyby V a lapping tool, thread forms upon a plurality of circular ring sectors .whichare adapted when s0 threaded to be mounted in a body member to form a thread ring gauge, said mechanism in cluding in combination, a holder, a nut, achuck', said not and chuck being co'axiall'y supported by the holder respectively at opposite ends-there; 2

radially extended from its central axis and in-.

eluding a follower shoe in. each channel, each shoe being adapted to bear upona circular ring sector interposed between said! shoehandfthje threaded lapping. tool, 'and means 'for yiemablv' urging teach. shoe toward the axis ofltlie chuck". to oorrespondinglypress' a" respective circular 5. ring sector upon the threads of the lapping tool during relative reciprocatory and rotary movement between the lapping tool and holder.

2. Mechanism for producing simultaneously by a lapping tool, thread forms upon a plurality of circular ring sectors which are adapted when so threaded to be mounted in a body member tdform a thread ring gauge, said mechanism including in combination, a holder, a nut, a chuck, said nut and chuck being coaxially supported by the holder respectively at opposite ends thereof, a lead screw engaged by thenut, a threaded lapping tool rigid with the lead screw, extended longitudinally through the chuck and coaxial therewith, said chuck having channels therein radially extended from its central axis and including a follower shoe in each channel, each shoe being adapted to bear upon a circular ring sector interposed between said shoe and the threaded lapping tool, means for yieldably urging each shoe toward the axis of the chuck to correspondingly press a respective circular ring sector upon the threads of the lapping tool during relative reciprocatory and rotary movement between the lapping tool and holder, and stop means for limiting movement of the circular ring sectors eiiected by movement of respective shoes. 3. Mechanism for producing simultaneously by a lapping process, thread forms upon a plurality of circular ring sectors which are adapted when so threaded to be mounted in a body member to form a thread ring gauge, said mechanism including in combination, a substantially cylindrical hollow holder having a nut receiving socket at one end and a chuck receiving socket at the opposite end, a nut, means for removably holding the nut in its socket in the holder, a chuck, means for removably holding the chuck in its socket in the holder, a lead screw engaged by the nut, a threaded lapping tool removably secured in rigid relation with the lead screw, extending longitudinally through the chuck and coaxially therewith, said chuck including a recessed body, blocks suitably arranged and secured in the recess of the chuck body thereby providing channels radially extended from the central axis of the chuck, and a follower shoe in each channel, each shoe being adapted to bear upon a circular ring sector interposed betweensaid shoe and the threaded lappin tool, means for yleldably urging each shoe toward the axis of the chuck to correspondingly press a respective circular ring sector upon the threads of the lapping tool during relative reciprocatory and rotary movement between the lapping tool and holder, and stop means for limiting movement of the circular ring sectors effected by movement of respective shoes.

4. Mechanism for simultaneously producing by a lapping operation, thread forms upon a plurality of circular ring sectors with the threads formed on each section correlated to the threads formed on the other sectors whereby the several sectors when suitably secured in a body member form a'thread ring gauge, said mechanism in cluding in combination, a threaded lapping tool, a support for maintaining a plurality of circular ring sectors in coplanar relation around the lapping tool, means for yieldably urging the sectors to move toward the rotational axis of the lapping tool in respective radial paths while maintained in coplanar relation and normal to said axis, and stops extended from the support and adapted to engage adjacent and surfaces of respective sectors to prevent radial movement of the sectors beyond a predetermined limit.

5. Mechanism for producing by a lapping operation, thread forms upon a plurality of circular ring sectors with the threads formed on each sector correlated to the threads formed on the other sectors whereby the several sectors when suitably secured in a body member form a thread ring gauge, said mechanism. including, a chuck, a threaded lapping tool extended longitudinally through the chuck and coaxial therewith, means for rotating and reciprocating the lapping tool relative to the chuck, said chuck having'channels therein radially extended from the coincident axes of the lapping tool and chuck, follower shoe confined in each channel for radial movement only, each shoe being engageable with a circular ring sector interposed between said shoe and the lapping tool, and means urging each slice toward the lapping tool.

6. Mechanism for producing by a lapping operation, thread forms upon a plurality of circular ring sectors with the threads formed on each sector correlated to the threads formed on the other sectors whereby the several sectors when suitably secured in a body member form a thread ring gauge, said mechanism including a chuck, a threaded lapping tool extended longitudinally through the chuck and coaxial therewith, means for rotating the lapping tool relative to the chuck, said chuck having channels therein for guiding respective circular ring sectors in definite radial paths while said sectors are in coplanar relation, a follower shoe confined in each channel for radial movement only, each shoe being engageable with a circular ring sector interposed between said shoe and the lapping tool, and means for independently urging each shoe toward the lapping tool.

7. Mechanism according to claim 6 also including, stops extended radially from the chuck in proximity to the lapping tool, said stops being adapted to engage adjacent end surfaces of respective sectors to prevent radial movement of he sectors beyond a predetermined limit.

8. Mechanism for producing by a lapping operation, thread forms upon a plurality of circular ring sectors with the threads formed on each sector correlated to the threads formed on the other sectors whereby the several sectors when suitably secured in a body member form a thread ring gauge, said mechanism including a threaded lapping tool, a support for the circular ring sectors arranged to confine movement of said sectors to a plane substantially normal to an axis about which the lapping tool and the support are relatively rotatable, means for yieldably urging said sectors radially against the lapping tool, and stops extended from the support for limiting movement of said sectors.

9. Mechanism for producing by a lapping operation, thread forms upon a plurality of circular ring sectors with the threads formed on each sector correlated to the threads formed on the other sectors whereby the several sectors when suitably secured in a body member, form a thread ring gauge; said mechanism including a chuck, a threaded lapping tool extended longitudinally through the chuck and coaxial therewith, means for rotating and reciprocating the lapping tool relative to the chuck, said chuck having channels therein radially extended from the coincident axes of the lapping tool and chuck, a follower shoe confined in each channel for radial movement only, each shoe being engageable with a circular ring sector interposed between said 7 shoe-and the lapping tool, a plate secured to the chuck and overlying the channels, and means within each channel for urging, the shoe therein toward the lapping tool.

, ALVIN E. LANGMAID.

ROBERT A. BLOOM.

- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Dane Number Kawa-hara Apr. 6, 1909 Number

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