DE2362291A1 - RESETTING DEVICE FOR THE SAW BLADE COVERING OF A PORTABLE SAW - Google Patents

Description

- ^ patent attorneys ---
F Weickmann,. **.

8 Munich 27, MoWstr. 22nd

Skil (Nederland) IKV.
Koni j nenbe rg 60
Box 267
Breda, Netherlands

Resetting device for the saw blade cover of a portable saw

The invention relates to a portable saw with a round Saw blade that is driven either electrically or pneumatically. Portable saws of this type come with a fixed one upper saw blade cover, which is part of the Saw housing forms, so / ie with a lower saw blade cover, which is between an open and closed position Can be swung back and forth so that the saw blade is exposed when the saw is placed on a workpiece, and so that the saw blade is covered at the times when the saw is not in contact with the workpiece. In particular, the invention relates to a manually operable one Mechanism for resetting the lower blade cover of a portable saw of the aforementioned type.

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It is known to use a hand-operated saw in portable saws Provide a reset device for the lower saw blade cover. For security reasons, this device is ciuf the side of the saw housing facing away from the lower cladding arranged. Actuation of the manually operated device causes the lower panel to be in the open position pivots. The panel is closed by pressing the operating handle or by pulling the latter simply lets go, whereupon a spring device pivots the lower panel back into its closed position.

The main disadvantage of such a reset device is in that the lower cover remains in its open position in which the saw blade is exposed, v / hen the operating handle is not released or is not returned to its closed position. This can be done under certain circumstances pose a significant risk. For example, if a worker standing on a ladder using the saw, his-balance loses, he may be so confused that he will push the handle of the saw or the switch that turns on the motor, does not let go. Serious injury could result.

Proposals have been made that deal with a device for an automatic return of the lower panel in. their closed position deal. In this connection, reference is made to US Pat. No. 1,900,553. In this patent a portable saw is shown, which has a lever device, which the lower cover with the Switch to operate the engine connects. If the switch remains in its closed position after the saw has moved from the When the workpiece has been removed, the lower cover will return to its fully closed position. Of the

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The main disadvantage of this known device is that the. The lower cover only partially opens and then snaps back into its closed position if the saw is not brought into contact with your workpiece immediately after the lower cover has been pivoted back. However, when making surface cuts, for example, it is common practice to swivel back the cover and then switch on the tool motor before the saw comes into contact with the workpiece. In the subject of the above-described patent specification, however, it is necessary to swing back the lower cover only partially and then to place the saw on the workpiece before the motor is switched on. Obviously, the use of such a chainsaw creates considerable danger due to the recoil. call, which is due to the fact that the circular saw blade is placed on the workpiece before switching on the saw motor.

The invention is characterized by one between one Closed position and an open position can be pivoted back and forth Actuating device, a device hinged to the lower fairing for transmitting a force, a spring device that the lower cover in the Closing position holds a releasable device that controls the actuating device connects with the device for transmitting a force and normally engaged with each other Has components, so that the movement of the actuating device in the opening division is a pivoting movement of the lower Cladding in the open position causes the detachable Device has a Noekeneinrichtung, which the components, depending on the movement of the lower cover into its open position, regardless of the position of the actuation

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transmission device disengages, so that the spring device the lower panel pivots into the closed position regardless of the position of the actuation device, and by a further cam device, which is dependent on the movement of the actuating device in its closed position ensures that the components intervene.

According to the invention it allows. Reset device that the lower panel is swiveled into the open position by hand regardless of whether the workpiece is touched by the saw or not, and the reset device takes care of it also ensures that the lower saw blade cover is automatically swiveled back after the saw has been removed from the workpiece regardless of the position of the hand switch. The inventive Reset device represents a significant safety factor for the portable saw.

According to a further advantageous feature of the invention is the actuating device is connected to levers for operating the lower saw blade cover by means of a detachable device, wherein the releasable device is operable to remove the lower blade cover from the actuating device depending on their movement separates when the lower cladding touches the workpiece.

According to a further feature of the invention it is provided that the releasable device can be reset to the lever device for the lower saw blade cover with to reconnect the actuator when the actuator is returned to the closed position. It is also contemplated that the lower panel be independent

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whether the saw is in contact with the workpiece or not, can be pushed back by hand.

Further features, advantages and details of the invention emerge from the following description of an exemplary embodiment with reference to the drawing. Show in it:

Fig.l is a perspective view of a portable chainsaw according to the invention;

FIG. 2 shows an enlarged "" partial rider and a partial section of the chainsaw shown in FIG. with only the parts forming the invention are shown;

FIG. 3 is an enlarged sectional view taken along line 3-3 of FIG. 2; "- ■ -

FIG. 4 shows a partial sectional illustration similar to FIG. 2, in which the position can be seen _r which the individual components occupy with respect to one another, the lower protective device being partially swiveled back;

5 shows an enlarged sectional view along the line 5-5 of Figure 4; -

FIG. 6 is a partial sectional view similar to FIG which shows the position that the individual components occupy with respect to one another, with the lower one

Protective device is swiveled back completely as a result of contact with the workpiece;

Fig. 7 is an enlarged sectional view along the line 7-7 of Figure 6;

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FIG. 8 is a partial sectional view similar to FIG which shows the position that the individual components occupy with respect to one another, with the lower one Guard is automatically pivoted into the closed position when the tool is off the workpiece is withdrawn;

FIG. 9 is a sectional view along the line 9-9 of FIG 3 and

FIG. 10 is an end view along the line 10-10 according to FIG. 9.

The present invention is advantageously used in a portable electric saw 10 as shown in FIG is. It goes without saying that the invention can also be applied to saws which have other drive means such as pneumatic motors.

The chainsaw 10 has a housing 11 with an upper fixed Protective device 12. As can be seen in Fig. 3, the upper protection device has an inner wall 14 and an outer wall 15 which form a cavity 16 in which a round saw blade 18 is added. The saw blade is well known Mounted on a drive shaft 19.

The saw housing 11 also has a handle 20 with a switch 21, which switches on the electric motor when it is pressed down, which sets the round saw blade 18 in rotation. The saw also comes with an adjustable base frame 22, which is preferably the method described in the earlier patent application Serial No. 206 639 (P 22-48 512.7) described con-

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has construction.

The lower saw blade cover 24 is pivotable on a bearing bush 25 arranged coaxially to the drive shaft 19. A preferred assembly design for such a lower saw blade cover and an associated cutting guide the saw is described in the earlier patent application serial no. 58530 (P2134990.6). The lower blade cover has an inner wall 26 and a curved outer wall 27, the two walls being connected to a wall 28 It should be noted that the lower saw blade cover 24 is received in the upper saw blade cover 12 when clockwise to its open position is pivoted.

There is a coil spring 30 is provided with one end on the inner wall 26 of the lower saw blade cover on one, is attached to the bearing bush 25 adjacent point. That The other end of the spring is in a suitable manner (not shown) on the inside of the upper saw blade cover 12 attached. The spring 30 pulls the lower saw blade guide continuously counterclockwise into its closed position.

A first lever 31 is pivotably articulated at one end by means of a bolt 33 on the wall 26 of the lower saw blade cover. This end of the lever is bent so that the "lever / engages around the bearing bush 25 and at one point" Ie the lower saw blade cover engages, which is necessary for the pivoting movement of the lower saw blade cover in their The open position is mechanically favorably located- The other end 'of the lever 31 is by means of a bolt 35 on that of its storage location distant 3nd of another

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Lever 34 pivotally attached. The other end of the lever 34 is articulated to a shaft 37 which is aligned in one another Bores 38 and 39 is rotatably mounted, which coaxially in the corresponding walls 14 and 15 of the upper one Saw blade cover are arranged. The lever 34 and the shaft 37 are set against each other so that they have a common Perform movement.

The shaft 37 has a thickened part 40. A fret ring 42 is mounted on the thickened shaft part 40 and can be rotated on this shaft part as well be shifted relative to the shaft part in the axial direction. The collar 42 is received in a chamber that is of a annular wall lla forming part of the housing of the chainsaw is formed.

A manually operable actuating device 44 has a bore 45 on one side, which is for receiving the rotating shaft part 40 is used. The shaft has a portion 46 with a reduced diameter in which a snap ring 47 is arranged, which locks the actuating device 44. The actuating device 44 has a annular recess 48 in which an O-ring 49 is arranged that prevents sawdust and other contaminants from entering the annular space that from the outer housing wall 11a and an annular one Surface 5O of the actuating device 44 is formed.

The part of the actuating device 44 having the bore 45 is provided with an annular recess 52, in which one end of a coil spring 53 is received. The other end of this spring is in an annular shape

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Sparung 55 stored, vzelche in the outer surface of the collar 42 is arranged. The spring 53 presses the collar 42 with respect to FIGS. 3, 5 and 7 in the axial direction to the right. At It should be noted at this point that suitable, in the Means not shown in the drawing are provided, such as a cotter pin connection, which ensure that the collar ring 42 axially to the shaft part 4O relative to the actuating device 44 moves and that the collar 42 depending on a Pivoting movement of the actuator rotates.

As can best be seen in FIG. 9 ', the shaft part 40 a diametrically arranged blind hole 57 in which a helical spring 58 and a bolt 59 are arranged ^. The / Coil spring 58 presses the bolt 59 out of the blind hole 57 so that the rounded outer end of the bolt 59 in a recess 60 is received on the inner surface of the collar 42 is provided. This recess has a, Wall surface 60a, which is formed in such a way that on the shaft 37 by the contact of the bolt 59 with a counterclockwise rotation of the Buhdririges 42 (see Fig. 9) a corresponding rotation is exerted. These Recess also has a cam surface 60b that the bolt 59 press into the blind hole 57 when the shaft 37 is rotated counterclockwise with respect to the collar 42 (see Fig. 9).

As can be seen in FIGS. 9 and 10, the collar ring 42 has an annular surface 61 with a cam, which is of a Wall part 62 and bucket wall 63 is formed. The wall 6 3 lies in a perpendicular to the longitudinal center axis of the collar arranged level. As will be explained below,

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serves this cam surface to against the outer end of a Bolt 64 to lie, v / elcher is held within a recess 65 with a snug fit, the recess in the housing of the saw is arranged in the upper saw blade cover 12.

The actuating device 44 has a stop 67. This stop comes against a stopper 68 to the plant, which counter to the pivoting movement of the actuating device limited clockwise. The stopper 68 can be formed in one piece with the inner wall 14 of the upper saw blade cover 12 be.

The function of the reset mechanism according to the invention is the following: -

FIGS. 2 and 3 show the device according to the invention in the position in which the lower saw blade cover 24 is in its fully closed position and when the actuator 44 is in the closed position * When the parts are in such a position, the bolt 59 is received within the recess 60.

Assume that actuator 44 is pivoted counterclockwise to lower the saw blade cover is pivoted back. Such a move of the actuating device causes a corresponding rotation of the collar 42. The rotation of the collar is the shaft part 40 is rotated in the same direction because the wall surface 60a of the recess 60 contacts the bolt 59, so that the rotation is transmitted from the collar 42 to the shaft part 40 will. It follows that the shaft 37 is rotated

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the lower saw blade cover by means of levers 31 and 34 24 to pivot into its open position ..

4 and 5 show an arrangement of the components when the Actuating device 44 pivoted into its fully open position The rotation of the actuator is limited by the abutment of the stop 67 against the stopper 68. When the rotating saw blade 18 through the workpiece moved through, then comes the lower saw blade cladding 24 also in contact with the workpiece. One such contact between the workpiece and the lower blade cover 24 leads to a further pivoting movement of the cladding, as shown in FIG. These additional movement of the lower saw blade cover to a rotation of the shaft part 40 relative to the collar 42. Such rotation causes the bolt 59 to come into contact with the cam surface 60b, so that the bolt 59 is pressed inwardly into the bore 57. Once the Bolt 59 is pushed out of the recess 60, the spring 53 moves the. Collar 42 in the axial direction with respect to on the Fig..7 to the right, whereupon the annular surface 61 of the collar against the bolt 64 comes to rest / It results from the fact that the collar 42 is now opposite the shaft part 4O is unlocked or free. Therefore, when the saw is removed from the workpiece, the spring 30 pivots the The lower saw blade cover 24 automatically returns to the fully closed position even when the actuating device 44 is held in its fully open position.

Assume now that the saw is moving away from the workpiece is ', while the actuating device 44 is at the same time in'

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their open position is held. When the worker moves the actuator 4 4 to the closed position (of course a spring device is provided to the actuating device reset after releasing), then the collar 42 is rotated so that the inclined cam-like formed wall surface 62 with the bolt 64 in contact comes. The inclined, cam-like wall surface 62, which rests against the bolt 64, displaces the collar 42 against the force of the spring 53 in the axial direction in order to align the recess 6O in relation to the shaft part 40, that the bolt 59 is received. This retrograde movement of the actuating device 44 also leads to the collar ring 42 being rotated to receive the bolt 59. If therefore the actuating device 44 is returned to its closed position, then the bolt 59 is under the influence of Spring 58 pressed back into recess 60, the mechanism being returned to a position in which the actuating device 44 with the lower saw blade casing 24 is connected.

As already stated, a spring device can be provided which moves the actuating device 44 back into its closed position after it has been released. This can be done by be achieved that the spring 53 is designed, for example, as a torsion spring, the opposite ends of which are attached to the actuating device 44 or on the upper saw blade cover 12 are attached (or on the housing part 11a).

From the foregoing description, it can be seen that the portable chainsaw has a new and improved reset mechanism is equipped for the lower saw blade cover, which represents a considerable safety factor.

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represents. The releasable mechanism between the actuator 44 and the lower blade cover 24 is shown in Actuated depending on a contact between the lower saw blade cover and the workpiece. Whenever the saw is lifted from the workpiece, the lower one pivots Saw blade cover 24 automatically into the closed position back, regardless of the position of the actuator 4 4 takes place. ..-_.;. "- ·.

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Claims (7)

Claims (1.! Reset device for the saw blade cover of a portable saw with a round saw blade, a fixed one upper and a pivotable lower saw blade cover, which is in an open position and in a closed position can be pivoted forward and backward, characterized by a. one between a closed position and an open position Position of the actuating device that can be swiveled forwards and backwards (44), b. a device (31,34,37,40) hinged to the lower casing (24) for transmitting a force, c. a spring device (3O) which holds the lower cover (24) in the closed position, d. a releasable device (37,42,59,60,60a, 60b) which the actuating device connects with the device for transmitting the force and normally with each other engaged components (59, 60) ", so that the movement of the actuating device in the open position a pivoting movement of the lower Cladding causes in the open position, wherein e. the detachable device has a cam device (6Oa _f 6Ob) which moves the components into their open position as a function of the movement of the lower cladding, regardless of the position of the actuation device - .. 14 - 4 0 ^r JB 2 5/0 9 Ci 2 disengages so that the spring means the lower cladding regardless of position, loading * activating device swivels into the closed position, xmd ; f. by a further cam device (62,63), which in Dependence on the movement of the actuator in its closed position ensures that the components engage. . * 2. Apparatus according to claim 1, characterized geke η η - ζ ei ch η et that a. the detachable device has a shaft (37) with a radially extending bore (57) and a loaded on it. has gerteii collar (42) opposite the shaft is rotatable and axially displaceable that 'b. the actuator. (44) with the collar and the shaft with the power-transmitting parts (31,34) are connected that c. the collar has a recess (60) with a first Wanclf pool (60a) and one part of the cam device forming cam surface (60b) that d. a bolt (59) is arranged in the bore (57), that .'.'·- e. a second spring (58) is arranged in the bore, which normally pushes the bolt outwards, one end of the bolt being received in the recess is and rests against the first wall, which together with the contact surface of the bolt, the force-transmitting Components forms that - 15 40982 B / 0902 f. a third spring (53) is provided which presses the collar in an axial direction and is used to force the Move the collar into this device when the bolt through the cam surface (60b) is out of the recess (6O) is pushed out by moving the shaft relative to Collar ring is rotated, and that G. a second cam device (62,63) is provided which moves the collar in the other direction when the actuating device is moved into the closed position. 3. Apparatus according to claim 2, characterized in that g e k e η η - ζ ei chnet that the force-transmitting device has a lever arrangement (31 _r 34) which connects the shaft (37) with the lower casing (24). connects. 4. Resetting device for the saw blade cover of a portable saw with a round saw blade, a fixed one upper and a pivotable lower saw blade cover, which can be pivoted back and forth into an open position and a closed position, g e k e η η - ze leans through a. one arranged on the saw housing, between a closed position and an open position pivotable actuating device (44), b. a spring device (30) which holds the lower cover (24) in the closed position, c. a power transmission device (31,34) which Actuating device (44) connects to the lower fairing in such a way that movement of the actuating device in its open position a significant A09825 / 090 2 causes speaking movement of the lower fairing. where ■, '■ "" ■' - d. the force-transmitting device is a detachable device (37,42,59,60,60a, 6Ob), by means of which the connection of the actuating device with the lower one Cladding depending on the movement of the lower panel in its open position independently is releasable by a movement of the actuating device, whereupon the spring (3O) the ^ lower cover regardless of the position of the actuation device pivots into its closed position and through e. a resetting device (62,63) which is activated by a movement of the actuating device in its closed position is actuated and the connection between the actuating device and the lower fairing again manufactures. -.-. · ■ 5. Resetting device for the saw blade cover of a portable saw with a round saw blade, a fixed upper and a swiveling lower saw blade cover, which is swiveled back and forth in an open position and a closed position, g e k e η η ζ e i c h net by a. a spring device (30) supporting the lower fairing (24) holds in the closed position, b. a shaft (37), c. a lever arrangement (31,34) which the shaft (37) so with the lower cladding connects that the Rotation of the shaft causes the lower fairing to pivot,. - 17 - 409825/0902 ze d. an actuator (44) with one on the Shaft-mounted collar ring which is rotatable and axially displaceable with respect to the shaft, the actuating device can be pivoted back and forth between an open and a closed position and exerts a corresponding rotary movement on the collar ring, e. a detachable device (59,6O, 6Oa, 6Ob, 62,63 "), the the collar with the shaft rotatably connects so that the collar and the shaft are rotated together can and the pivoting movement of the actuator in its open position causes a corresponding movement of the lower panel, wherein f. the releasable device comprises a first cam device (60,6Oa, 60b), by means of which the collar and the shaft depending on a rotation of the Shaft relative to the collar can be disengaged, and through G. a second cam device (62,63) which is dependent on the rotation of the collar relative to the shaft re-establishes a connection between the Buhdring and the shaft. 6. Apparatus according to claim 5, characterized in that a · the detachable device from a bolt (59). educated which is slidably received in a bore (57) arranged in your shaft part (40), as well as by a recess (60) "which is arranged in the collar (42), one end of the bolt normally is received in the recess (60) that - 18.09.25 / 0902 b. the first cam means has a cam surface (60b) - which forms part of the recess (60) and ensures that the bolt (59) comes out of the recess when the shaft rotates relative to the collar is expressed that c. the releasable device also has another spring (53) which moves the collar axially in one direction, when the bolt (59) has come free from the recess is and that d. the second cam means a cam (62,63) and a cam follower (64) supporting the collar pushes axially in the other direction. 7. Apparatus according to claim 6, characterized in that g e k e η η ζ e i c h n-e t that the collar (42) opposite the Actuating device (44) is axially displaceable and that the. another spring (53) between the actuator and the collar is arranged. - 19 409825/090