JP2635744B2 - Jigsaw - Google Patents

Description

The present invention relates to a jigsaw, and more particularly, to a jigsaw provided with a blade holding device that allows a saw blade to be replaced without using a tool outside the structure of the jigsaw itself.

In known jigsaw constructions, the blade is, for example, US-A-366598.
By means of fixing screws which engage the lateral surface of the blade as shown in FIG. 3 and tighten the blade in place or by GB-A-11
As shown in 73172 (where the blade comprises a bayonet lug, which in use is provided with a screw that engages the end of the blade in a corresponding retaining groove formed in the end cap of the drive shaft. ), And is fixed to a reciprocating drive shaft by a mechanism combining a bayonet and a fixing screw.

Both of these mechanisms have the disadvantage of requiring the use of an external tool (screwdriver) for blade replacement.
Not only is this inconvenient, but inexperienced or careless workers can damage the retaining screw during blade replacement or inadvertently drive the blade during use as a result of insufficient tightening of the fixing screw. There is a risk of off-axis.

According to the invention, the end has a bayonet fitting for receiving a blade having a bayonet lug,
Moreover, a jigsaw with a drive shaft having locking means for engaging the blade to retain the lug in the retaining groove of the bayonet fitting during use of the jigsaw, wherein the locking means is incorporated within the body of the jigsaw. The bayonet lug is disengaged from the holding groove by using the disengagement device and can be moved to the disengagement position where the removal of the blade and the insertion of the new blade can be performed. It can be moved to the disengagement position without using a tool.

Thus, the disadvantages of the prior art, which require a screwdriver to remove one or more retaining screws, are avoided.

Advantageously, the locking means is movable into the release position by means of a release device which is integrated in the jigsaw and is permanently connected to the locking means. With this arrangement, damage to the locking means caused by partial or incorrect engagement of the release device is avoided. Further, the dissociation device advantageously includes a hand-gripable dissociation member for operating the dissociation device, the dissociation member being configured to not move during normal reciprocation of the drive shaft. I have.

In a particularly preferred embodiment of the invention, the locking means is GB-A
1-17 is a possible screw in the axial direction of the drive shaft in a manner similar to the prior art arrangement shown at 1173172. In this case, the disengaging device advantageously comprises a screw-rotating member extending axially into the drive shaft, allowing relative sliding between the screw and the screw-rotating member, but between the screw and the screw-rotating member. The screw rotating member is permanently engaged with the screw in such a manner as to prevent relative rotation of the screw. In this case, the manually gripping release member is connected to the screw rotating member for rotating the screw rotating member and thereby rotating the screw. Advantageously, a torque limiting device is arranged between the hand-gripable release member and the screw rotating member to limit the torque that can be applied to the screw in a direction that causes the screw to move towards the blade. . In this way damage due to overtightening of the screws is avoided. Advantageously, the torque limiting device does not limit the torque that can be applied by the manually grippable release member in the direction away from the blade.

In another embodiment of the invention, the locking means comprises a spring, which preloads the blade in the direction outside the drive shaft for holding the bayonet lug in the holding groove. Advantageously, the locking member is arranged between the spring and the blade, and the release device comprises a tensioning member connected to the locking member and to a manually operable tensioning device, whereby the locking member compresses the spring. Then, it is moved to allow the blade to be removed.

In extreme operating conditions, for example when a jigsaw is used with the blade bottom hitting a hard surface, the locking means allows a limited movement of the blade in the direction towards the inside of the drive shaft against the preload of the spring. This results in a particularly advantageous embodiment of the invention. With such an arrangement, the impact applied to the drive shaft and the rest of the jigsaw mechanism is significantly reduced.

Advantageously, the locking member prevents rotation of the blade relative to the drive shaft, except when the locking member is raised to the disengaged position.

The invention will be better understood from the following description of two configurations, which are merely exemplary. Regarding the accompanying drawings: FIG. 1 is a perspective view, partially cut away, of a first embodiment of the present invention, and FIG. 1A is a cam nut which is suitable for use in the embodiment of FIG. Figure showing how to attach to the
2 is a partially enlarged view of the embodiment of FIG. 1, FIG. 3 is a diagram showing a modification of the embodiment of FIG. 1, and FIG. 4 is another modification of the embodiment of FIG. FIG. 5, FIG. 5 is a partially cutaway view of the second embodiment of the present invention, FIG. 6 is an exploded view of the components of the embodiment of FIG. 5, and FIG. FIG. 8 is an exploded view of a modification of the embodiment, and FIG. 8 is a partial cross-sectional view of the modification shown in FIG. 7 in a normal use arrangement.

Referring first to FIGS. 1 and 2, a jigsaw 1 having a main body 2 and a drive shaft 3 is shown partially broken,
The drive shaft reciprocates axially in use in a conventional manner.
In use, the blade 4 is connected to the exposed end 5 of the drive shaft via a bayonet fitting 6.

The bayonet fitting consists of an end cap 7 which is fixed to the main part of the drive shaft 3 and has a pair of diametrically opposed inlet slots 8 and a pair of diametrically opposed retaining grooves 9. The retaining groove 9 is circumferentially offset 90 ° from the inlet slot 8. The configuration of the end cap 7 is substantially the same as that described in GB-A-1173172.

In a normal use arrangement of the jigsaw, bayonet lugs 10 provided on the blade 4 and facing each other in a direct direction are arranged in the holding grooves 9. In this case, as shown in FIGS. 1 and 2, the ascending movement of the drive shaft is transmitted to the blade to perform the ascending cutting stroke of the blade.

With particular reference to FIG. 2, the bayonet lug 10 of the blade 4
The portion from directly below to the upper end 11 of the blade is formed in the lock member 13 and is a slot 12 opened at the bottom of the lock member.
Housed inside. The locking member is preloaded downward by a compression spring 14, as seen in FIG. 2, and engages the upper end 11 of the blade to exert a spring force on the blade. Thus, as seen in FIG. 2, the blade is preloaded downward by a spring 14, and this is sufficient to hold the lug 10 in the holding groove 9 during normal operation of the saw.

When working on the saw, for example, due to friction, tightening and / or extremely high operating forces on the saw by the operator, a high holding force (Festhaltekr) between the workpiece to be machined and the saw blade
fte) may occur. Under such extreme operating conditions, a large upward impact force in the axial direction causes the saw blade 4
In this case, the blade can move a limited amount above the position shown in FIG. 2 against the preload of the spring 14. The blade 4 is a lock member by the upward movement.
Lift 13 and thus compress spring 14. As soon as the upward axial force is removed from the blade, the spring 14 returns the locking member 13 to the position shown in FIG.
Will return 10 to groove 9. Under these circumstances, the upward axial movement of the blade is limited by the engagement of the upper surface 15 of the lug 10 with the shoulder 16 provided on the drive shaft.

The lock member 13 has a pair of outwardly extending lugs 17 which are located in the inlet slots 8 to prevent rotation of the lock member 13 in the drive shaft 3 under normal operating conditions. doing. The axial overlap between the lug 17 and the inlet slot 8 is greater than the normal distance between the upper surface 15 of the lug 10 and the shoulder 16 so that even when the upper surface 15 and the shoulder 16 are engaged, the lug 17 Is still in the part entry slot 8. Thus, under extreme operating conditions, limited axial movement of the blade 4 is allowed, but rotational movement of the blade 4 relative to the drive shaft is prevented by the engagement of the lug 17 in the inlet slot 8.

To release the blade 4, the locking member 13 is lifted from the position shown in FIG. 2 to the position shown in FIG. 1 by the release devices (18 to 24). Thus, tension is applied to the tension member 18, for example, a wire or Bowden cable connected to the locking member. When the lock member 13 is lifted in this way, the spring
14 is compressed and the blade 4 is released from the spring preload. When the locking member 13 has been lifted sufficiently to release the lug 17 from the inlet slot 8, the blade 4 is grasped by hand and rotated through 90 ° so that the locking member 13 is in a position where the bayonet lug 10 aligns with the inlet slot 8. You can rotate up to. The blade can then be manually removed and a new blade inserted. After the new blade is inserted
Hold the new blade bayonet lug 10 by hand rotation over 90 ° and remove the tension from the tension member 18.
The preload spring 14 is reapplied to the blade to retain within.

The tension can be applied to the tension member 18 using any suitable means. In the embodiment of FIG. 1, the upper end of the tension member 18 is fixed to a cam nut 19, which moves on a screw spindle 20 fixed to the upper end of the drive shaft 3. The cam nut 19 has a pair of diametrically opposed ribs 21 which move in slots 22 formed in a nut rotation member 23. Although in FIG. 1 the central portion of the member 23 has been broken to show the cam nut 19 and the threaded spindle 20, it will be appreciated that the cam nut is usually completely contained within the member 23.

The member 23 is fixed in the body of the jigsaw for reciprocating movement, so that the reciprocating movement of the drive shaft during normal use of the jigsaw causes the cam nut 19 to reciprocate in the member 23 and the ribs
The 21 moves in the slot 22. If it is desired to tension the tension member 18, the nut rotation member 23 is rotated by appropriate means to provide a corresponding rotation of the cam nut. This, in turn, causes the cam nut to rise on the threaded spindle 20 and provide tension to the member 18 in the desired manner. It should be noted that with this arrangement, the lifting movement of the cam nut relative to the drive shaft can be obtained independent of the position of the drive shaft in its operating cycle.

The member 23 can be rotated by any suitable means, such as a manually operable lever 24, which is pivotally mounted on the body and is coupled to the member 23 via an intermeshing bevel gear 25. .

FIG. 1A shows one possible configuration for securing the tension member 18 to the cam nut 19. In this configuration, the tension member 18 is in the form of a wire, the end area 18A of which is bent and fixed in place, forming a head 40 at the upper end of the tension member. The tension member 18 extends through plates 41, 42 having a pair of slots. In use, these plates are arranged in recesses 43 formed on the upper surface of the cam nut 19. Since the slots in these plates receive the tension members 18 closely and are oriented at 90 ° to each other, the head 40 cannot pass through the passageway formed by the plates.

In the variant of FIG. 1 shown in FIG. 3, a cam surface 26 is provided at the upper end of the drive shaft, and when the member 23 is rotated, the lower edge 27 of the cam nut rib 21A is brought into contact with the cam surface 26.
Move up to generate the desired axial movement of cam nut 19A relative to the drive shaft.

In the variant shown in FIG. 4, the cam nut 19, the screw spindle 20 and the rotating member 23 are similar to the configuration of FIG. However, the rotation of the member 23 is performed by a slide member 44, and the slide member is provided with a rack 45, and the rack meshes with pinion teeth 46 formed on the member 23. Thus, the sliding movement of slide member 44 in the direction indicated by arrow 47 causes member 23 to rotate, causing the cam nut to rotate, and imparting tension to member 18 as described above.

Reference is now made to FIGS. 5 and 6, which show another embodiment of the present invention. In this embodiment, the driving shaft 3
Has an end cap 7 substantially identical to that shown in FIG. 2, with a bayonet fitting 6 provided for receiving a suitable blade. The bayonet fitting device is also similar to that shown in GB-A-1173172. In this embodiment, however, the bayonet lug of the blade is held in the holding groove of the end cap 7 by a screw 28 as usual, and the screw 28 engages the inner surface of the hollow drive shaft 3. The screw 28 is arranged to engage the upper end 11 of the blade to apply a downward force to the blade to retain the bayonet lug of the blade in the retaining groove of the end cap.

The screw 28 is operated by a dissociation device 29-37 and has an extension 29 with a D-shaped cross section. In all operating positions of the drive shaft 3, the extension 29 axially overlaps the screw rotating member 30, which also has a substantially D-shaped cross section. Therefore, the extension in the range of the axial overlap 31
The screw rotating member 29 and the screw rotating member 30 have opposed flat surfaces which slide on each other.

The screw rotation member 30 extends upward in the drive shaft and terminates in a suitable rotation mechanism 32. During normal use of the saw, this mechanism 32 holds the screw rotating member 30 in a fixed position relative to the jigsaw casing, and the axial reciprocation of the drive shaft and screw 28 provides for axial overlap. It is accommodated by an axial sliding movement between the extension 29 and the mutually facing surfaces of the screw rotating member 30 in the zone 31. When it is desired to remove the screw 28 in order to disengage the held blade, the screw rotating member 30 is rotated by the rotating mechanism 32,
And this rotation is transmitted to the screw extension 29 in the zone of the overlap 31 to effect the rotation of the screw. After inserting the new blade, the member 30 is rotated in the opposite direction and the screw 28 is tightened.

Advantageously, the rotation mechanism 32 is screwed as shown in FIG.
It incorporates means to limit the torque that can be applied to member 30 in the direction that moves 28 downward, thereby preventing over-tightening of the screw.

A mechanism 32 for providing torque limiting in the tightening direction is shown in FIG. The upper end of the screw rotating member 30 is a ratchet member 33
, And the ratchet member is driven via the claw bush 34 in use. The pawl bush has an integral finger 35 that engages a slot 36 on the outer periphery of the ratchet member 33. The pawl bush 34 is molded from a suitable plastic material so that the finger 35 is flexible and can slide with a predetermined torque onto the teeth formed between the slots 36 of the ratchet. Finger 35 and slot
36 forms torque limiting mechanisms 35,36. Advantageously, the tooth and ratchet tooth profiles are selected such that the snapover torque in the direction of tightening the screw 28 is limited to an advantageous value, e.g. 1 Nm, but the reverse snapover is substantially prevented, This allows a high level of torque to be provided through the pawl bushing to remove the screw 28.

The pawl bush 34 may be provided by any suitable means, such as a drive lever 37
Can be driven by a dissociating member configured as
The drive lever is permanently fixed to the jigsaw housing and includes a tubular body 38 surrounding the pawl bush 34. The inside of the tubular body 38 has a pair of ribs 39 (only one is visible in the figure), which are received in slots 48 of larger dimensions of the pawl bushing, and thus the lever
A rotary pneumatic connection is formed between 37 and the pawl bush 34.

To cooperate with appropriate means provided on the jigsaw body to hold the lever in the rest position shown in FIG. 5 during normal use of the jigsaw, the tubular body has raised ridges 50 on its outer surface.
Is provided. Lever 37 in this position
Is flush with the adjacent surface of the jigsaw body. However, the lever is grabbed and pulled in the direction indicated by arrow 53 to snap on ridge 50 onto the cooperating means of the body,
And the lever can be brought to the use position. In this use position, the lever rotates and the pawl bush 34 and ratchet member
33 can be rotated to release the claws as described above. After inserting the new blade, the screw 28 is tightened by rotation of the lever 37 until the pawl bush 34 begins to snap over the ratchet teeth. The rotation of the lever 37 is continued until the lever is substantially aligned with the body, at which time the idle motion obtained between the rib 39 and the slot 48 pushes the lever down and causes the ridge 50 to cooperate on the body. It is used to facilitate final alignment of the lever relative to the body before snapping over the working means and returning the lever to the rest position shown in FIG. This arrangement ensures that the torque limiting member 32 is not stressed when the lever is in the rest position.

In order to hold the pawl bush 34 in the correct operating position relative to the ratchet member 33, a snap connection may be formed by the head 51 and pawl bush groove 52 on the ratchet member. Once the head 51 is pushed into the groove 52, the ratchet and pawl will be held in the correct, relative axial position, but they will rotate relative to each other if necessary to limit torque. can do.

Referring now to FIGS. 7 and 8, there are shown alternative configurations for applying the desired torque to the screw rotation member 30. FIG. In this case, the upper end of the screw rotating member 30 is fixed to the ratchet member 54, and the ratchet member is driven via the pawl bush 55 at the time of use. 6, the pawl bushing 55 includes a single finger 35, which is a peripheral slot in the ratchet member 54.
Cooperates with 36 so that the pawl and ratchet mechanism can transmit only a limited torque to the screw rotating member in the direction of tightening the screw 28, but in the opposite direction.
Does not limit the torque that can be applied to the 30.

As shown in FIG. 8, the ratchet member 54 and pawl bush 55 are housed in a normally open chamber 56 formed inside a knob 57 which can be grasped by hand. The lower part of the chamber 56 is formed by a plurality of spring fingers 58, each of which has outwardly facing teeth 59 at its lower end. In a normal use arrangement, as shown in FIG. 8, the teeth 59 engage below the inward flange 60 provided on the jigsaw body, thereby retaining the knob on the jigsaw body. It is freely rotatable relative to the body. An outwardly directed flange 61 at the lower end of the ratchet member 54 is interference fit within the finger 58 at the location of the tooth 59, thereby preventing radial inward movement of the finger 58 and thus the knob is located on the jigsaw body. Moored. The ratchet member 54 is preloaded upwardly by a spring 62 and brought to the position shown.

An operating member 63 is arranged in the knob 57 in such a manner as to prevent relative rotation between the operating member and the knob. To accomplish this, in the embodiment shown, the operating member has a head 64, which is located in the recess 65 of the knob and has a pair of outward lugs 66. The lug 66 is disposed in a slot 67 formed in the knob, thereby preventing the operation member from rotating relative to the knob. Operation members
63 also has a shank 68 which is recessed downward from the head 64
It passes through the bottom of 65 and into chamber 56. The lower end of the shaft 68 has a spline 69 for cooperating with a mating spline 70 provided on the pawl bush 55.

In the normal use arrangement shown in FIG.
Is located below the position of the spline 70 in the pawl bushing, so that there is no driving engagement between the two splines. Thus, rotation of knob 57 relative to the jigsaw body will result in a corresponding rotation of operating member 63, but the operating member does not cause rotation of pawl bush 55. When it is desired to rotate the screw rotating member 30 by rotating the claw bush 55 to remove the blade, the lug 66 is grasped, and the operating member 63 is moved in the direction indicated by the arrow 71, and the spline 69 and the spline 70 are separated. It is engaged.
The amount of momentum allowed for the operating member is less than the amount required to remove the lug 66 from the slot 67, and
When the 69 and 70 are engaged with each other, the knob 57 can be gripped and rotated, and the claw bush 55 can be rotated via the operating member 63 and the engaged spline. After the new blade is inserted, the screw 28 is tightened again by turning the knob 57 in the opposite direction. The pawl bushing 55 and the ratchet member 54 will limit the tightening torque that can be applied as described above.

If you want to remove knob 57 for any reason,
63 is pressed (moved in the direction opposite to the arrow 71) to press the ratchet member 54 and the screw rotating member 30 against the preload of the spring 62. As soon as the flange 61 is disengaged from the lower edge of the finger 58, the knob 57 can be pulled upward and the finger 58 can move radially inward, thus allowing the tooth 59 to disengage from the flange 60.
The knob 57 can then be pulled out of the jigsaw together with the operating member 63 and the claw bush 55. The knob assembly can be repositioned simply by pushing it into place so that the lower end of the finger 58 engages the upper surface of the flange 61 to form the ratchet member 54 and the teeth 59 are formed by the flange 60. Pressing enough to allow it to pass through the opening, in which case fingers 58 return outward, engaging teeth 59 under the flange, and ratchet member 54 repositioning the position shown in FIG. Allow to occupy.

With the exception of the screw rotation member 30 and the spring 62, the rotation mechanism as described above, and in particular the various components of the pawl member and the ratchet member, are advantageously manufactured by injection molding from a plastics material.

Although the screw extension 29 and the screw rotating member 30 are illustrated above as having a D-shaped cross section, these components provide a relative axial sliding motion, but the relative rotation of the members relative to each other. It will be appreciated that it may have any complementary cross section to block. Furthermore, the extension 29 and the screw rotating member
It will be appreciated that 30 opposed sliding surfaces are advantageously treated to provide wear resistance, for example by a carbonitriding process.

Claims (10)

(57) [Claims] 1. A bayonet fitting (6) at the end for receiving a blade (4) with a bayonet lug (10).
A jigsaw having a drive shaft (3) with locking means (13, 14 or 28) for engaging the blade to hold the blade leg in the holding groove (9) of the bayonet fitting during use of the jigsaw. And locking means (13, 14
Or 28), in which the bayonet lugs are disengaged from the retaining groove and can be moved to a disengaged position allowing the removal of the blade and the insertion of a new blade, the locking means (13, 14 or 28) being used. The jigsaw (1) can be moved to the dissociation position without using a tool separate from the jigsaw using a dissociation device (18-24 or 29-37) incorporated in the main body (2) of the jigsaw (1). Yes, jigsaw. 2. A disengagement device (18-24 or 29-37) is permanently connected to the locking means (13, 14 or 28) and moves during normal reciprocation of the drive shaft (3). 2. A jigsaw according to claim 1, including a hand-gripable release member (24 or 37). 3. A screw (28) which is movable in the axial direction of the drive shaft so that the locking means engages with the end (11) of the blade, the disengaging device being axially movable in the drive shaft (3). Consists of an extended screw rotating member (30), which allows a relative sliding movement between the screw and the screw rotating member, but the screw (28) and the screw rotating member (3
3. The jigsaw according to claim 2, wherein the screw rotation member is permanently engaged with the screw in such a way as to prevent relative rotation between the screw rotation member and the screw rotation member. 4. A disengagement member (37) that can be grasped by hand via a torque limiting member (35/36) that limits the torque that can be applied to the screw in the direction that moves the screw toward the blade. The jigsaw according to claim 3, wherein the jigsaw is connected to a rotating member (30). 5. The locking means (13, 14) comprises a spring (14), the blade extending outwardly of the drive shaft (3) such that the spring retains the bayonet lug (10) in the retaining groove (9). Means (18) for preloading (4) and for compressing the spring (14) such that the release device releases the blade from the spring preload.
The jigsaw according to claim 1 or 2, further comprising: 6. A locking member (13) comprising a spring (14) and a blade (4).
And the dissociation device is provided with a tension member (1
8), wherein the tensioning member is moved to the locking member (13) and pulls the tensioning member (18) to move the locking member (13), thus manually operable to compress the spring (14). 6. The connecting member according to claim 5, wherein the connecting member is connected to a tension member.
The described jigsaw. 7. A locking member (13) for limiting the inward movement of the drive shaft (3) of the blade (4) against extreme preloading of the spring (14) under extreme operating conditions, and The jigsaw according to claim 5 or 6, wherein the jigsaw is configured to prevent relative rotation of the blade (4) with respect to the drive shaft (3) except when the blade (4) is moved to the disengagement position by the operation. 8. The bayonet fitting (6) so that the lock member (13) has a lug (17), and the lug prevents relative rotation between the lock member (13) and the drive shaft (3) during use of the jigsaw. 6. Engagement with said inlet slot (8).
The jigsaw according to any one of claims 1 to 7. 9. A tensioning device (17-24) comprising a cam nut (19) coupled to a tension member (18); a threaded spindle (20) is associated with a drive shaft (3) for cooperating with the cam nut. Fixed; and the nut rotating member (23) allows relative axial sliding movement between the nut rotating member (23) and the cam nut (19), but the nut rotating member (23) and the cam nut (19) 9. A jigsaw according to claim 6, wherein said jig is engaged with a cam nut in such a manner as to prevent relative rotational movement of the jig. 10. A detachable member (37) that can be gripped by hand.
Are connected to the screw rotating member (3) via pneumatic connections (39,48) which allow limited rotation of the disengaging member (37) without causing a corresponding rotation of the screw rotating member. 5. Jigsaw according to claim 3, wherein the limited rotation is adapted to the number of teeth on the pawl bush (34).