GB2302060A

GB2302060A - Jigsaw blade clamp

Info

Publication number: GB2302060A
Application number: GB9611658A
Authority: GB
Inventors: Nicolantonio Aldo Di; Rene Gentinetta
Original assignee: Scintilla AG
Current assignee: Scintilla AG
Priority date: 1995-06-10
Filing date: 1996-06-05
Publication date: 1997-01-08
Anticipated expiration: 2016-06-05
Also published as: DE19521246A1; DE19521246B4; CH691221A5; ITMI961058A1; JPH09103914A; ITMI961058A0; CN1069250C; GB9611658D0; GB2302060B; IT1295693B1; CN1142999A

Description

1 iiqsaw State of the art 2302060 The invention is based on a jigsaw

according to the generic type of claim 1.

A jigsaw of the generic type is known from DE-OS 41 38 986. In this jigsaw, the possibility of saw blade replacement is advantageously provided in that a switching sleeve is mounted on the gearing housing so as to be rotatable and fixed to the housing and can be pivoted about its axis by external manual intervention. The pivoting movement of the switching sleeve is transferred via a cam to the clamping sleeve of the mechanism for clamping the saw blade. The switching sleeve has a grip member which needs to be manually pivoted about the lifting rod axis so that the saw blade can be removed. The switching sleeve is rotatably secured in the gearing housing via a plurality of bearing points. These bearing points are subjected to a high degree of wear by the sawdust. Furthermore, it is necessary to secure the switching sleeve in its release position by hand. This means that saw blade replacement is relatively complicated and time-consuming.

Advantaqes of the invention AS compared with the state of the art, the jigsaw according to the invention which has the characterising features of claim 1 offers the advantage that saw blade replacement can be carried out comfortably and quickly by way of a favourable direction of movement for the hand of the operator, preferably a downward movement, and that it is only necessary to actuate the switching sleeve in one direction, i.e. in order to release the saw blade, but not in order to clamp the saw blade. In addition, it is not 2 necessary to manually secure the switching sleeve when the saw blade is being removed or when a new saw blade is being introduced. Rather, the switching sleeve can be released once it has reached the release position, whereupon it 5 returns to its starting position.

Further advantageous developments of the invention are contained in the dependent claims.

Drawings Embodiments of the invention are explained in further detail in the following description with the aid of the associated drawings.

Figure 1 shows an embodiment of a jigsaw accord-ing to the invention, Figure 2 a mechanism for clamping the saw blade, Figure 3 is a view of Figure 2 from below, Figures 4 and 5 are a perspective and plan view respectively of an embodiment of the actuating mechanism for rotating the clamping sleeve, Figures 6 and 7 are a perspective and plan view respectively of a further embodiment for a pivot lever for rotating the clamping sleeve, Figures 8 and 9 show an adjusting member constructed as a traction cable for rotating the clamping sleeve, Figures 10, 11 and 12 show a switching sleeve which can be vertically actuated, Figure 13 shows an adjusting member which can be actuated by a toothed rack, Figure 14 shows an actuating member which can be actuated by a linear slide and Figure 15 an adjusting member which can be actuated by gearing.

3 Descrintion of the embodiments A jigsaw 10 illustrated in Figure 1 comprises a motor housing 12, which is flanged onto a gearing housing 14.

The motor housing 12 and the gearing housing 14 are together mounted on a base plate 16.

When viewed from below, a lifting rod 18 emerges from the gearing housing 14 and is axially displaceably mounted in the gearing housing 14 in a lower and an upper lifting rod mount, not illustrated. At its lower end, the lifting rod 18 supports a clamping mechanism 20 with a clamping sleeve 21 for clamping and centring the saw blade clamping end 22 of a saw blade 23.

is The saw blade 23 penetrates a recess 25 in the base plate 16 in the axial direction. A double-arm lever 27, which is formed by arms arranged at right angles to one another, is arranged on the side of the gearing housing 14. One of the arms is constructed as a push lever 28 and the other as a trigger 29. The arms are pivotable about a common pivot axis 30. The trigger 29 is longer than a possible stroke of the lifting rod 18 and during its pivoting movement contacts a cam 21', which is supported by the clamping sleeve 21 so as to project radially beyond the circumference thereof.

When the push lever 28 is actuated, the trigger 29 brushes past the clamping sleeve 21 and thereby drives the cam 211.

The pivoting movement of the trigger 29 is thereby translated into a rotary movement of the clamping sleeve 21. In an end rotary position, the clamping sleeve 21 releases the clamping end 22 of the saw blade 23, so that the latter can be removed axially.

Figure 2 shows a lifting rod 18 with a mechanism 20 for clamping a saw blade 23. A stepped piston-like centring 4 sleeve 52 has a circumferential bevelled face 54, by means of which locking balls 531, 541 can be displaced radially into radial bores 68, 69 in the lower region of the lifting rod 18 when the centring sleeve 52 is displaced axially.

The lifting rod 18 extends radially outwards in stepped fashion into a collar-like external threaded element 26. Following this element 26, the contour of the lifting rod 18 extends radially inwards in stepped fashion and from here extends substantially linearly with a reduced diameter as far as its lower edge 32.

Internally, the lifting rod 18 comprises a central, axial stepped bore 27, which gives the lower region of the lifting rod 18 a tube-like form. The central stepped bore 27 ends in a conical bore 33.

A clamping sleeve 21 is threaded onto the external threaded section 26 of the lifting rod 18. In its lower region, the clamping sleeve 21 extends radially inwards into a collar 46, whose internal contour is formed by a through opening 48 and a radial slot 47. Adjacent each of the radial bores 68, 69 of the lifting rod 18, the clamping sleeve 21 comprises a locking groove 55, 56 on its internal circumference.

The lifting rod 18 and the clamping sleeve 21 are coupled to one another in a prestressed manner via a torsion spring 42, the lower spring end 43 engaging in a radial recess 43, in the lifting rod 18 and the upper spring end 44 in a radial recess 441 in the clamping sleeve 40 (Sic). By means of a corresponding prestressing of the torsion spring 42, the clamping sleeve 21 is secured in an abutment position in which it is pushed axially upwards relative to the external threaded element 26.

Supported against the upper end face 57 of the centring sleeve 52 is a compression spring 58, which attempts to push the centring sleeve 52 downwards relative to the lifting rod 18. Locking balls 53', 54' are arranged in a radial intermediate space between the cylindrical region 51 of the centring sleeve 52 and the stepped bore 27. These balls sit in radial bores 68, 69 in the wall of the lifting rod 18.

The narrow side of the upper region of the saw blade clamping end 22 is centred in the conical bore 33 in the upper region of the lifting rod 18. The upper end faces of the saw blade noses 49, 50 are centred in a Vshaped groove 60 in the lower end face 59 of the centring sleeve 52. The inner end face 46' of the collar 46 of the clamping sleeve 210 is supported against the lower end faces of the saw blade noses 49, 50, of which only the nose 49 is visible on account of the lateral view of the saw blade 23. The inner end face 46' thereby holds the saw blade 23 in the mechanism 20 so that it is secured against loss or from escaping in a downward direction. The clamping sleeve 21 comprises a radial cam 211 for actuating its rotation.

Figure 3 is a view of the mechanism 20 from below, showing the clamping sleeve 40 with the shape of its through opening 48, the radial slot 47, the collar 46 and the radial cam 211.

The mechanism 20 operates in the following manner: In order to release the saw blade 23, the clamping sleeve 21 is rotated relative to the external threaded element 26 and effects a simultaneous axial displacement in a downward direction as a result of its threaded connection with the external threaded element 26. Once a given abutment position is reached, further rotation of the clamping sleeve 21 is impossible, since the locking grooves 55, 56 are aligned with the radial bores 68, 69 in this position.

6 The saw blade 23 travels axially downwards following the axial displacement of the clamping sleeve 21. During this movement, the centring sleeve 52 follows the saw blade 23 as a result of the loading by the compression spring 58, with the centring groove 60 supported against the saw blade nose 49, 50. In this respect, the bevelled faces 53, 54 come to rest against the locking balls 531, 541 and displace these radially outwards. The locking balls 531, 541 of the centring sleeve 52 thereby enter the locking grooves 55, 56. As a result of the force of the compression spring 58, the position of the locking balls 531, 541 is secured via the centring sleeve 52. The clamping sleeve 21 is locked in its rotary position by the action of the locking balls 53', 54'. It cannot move back into its starting position, its radial slot 47 being aligned in the open position with the plane of the saw blade 23, so that the saw blade 23 can be easily removed from below or is ejected, since the centring sleeve 52 is prestressed by the compression spring 58.

In order to insert a saw blade 23, the latter is introduced with its clamping end 22 axially upwards into the through opening 48 or the radial slot 47 in the clamping sleeve 21.

As soon as the upper end faces of the saw blade noses 49, 50 come to rest against the centring groove 60, 61, the centring sleeve 52 is moved together with the saw blade 23 axially upwards against the compression spring 58. The bevelled faces 53, 54 release the locking balls 53', 541.

As a result of the action of the torsion springs 42 and the resulting rotation of the clamping sleeve 21, the locking balls 53', 541 are conveyed from the locking grooves 55, 54 back into the radial intermediate space between the centring sleeve 52 and the central stepped bare 27 or into the radial bores 68, 69. The clamping sleeve 21 is then unlocked, can rotate further and thereby move axially upwards. During this process, the radial slot 47 rotates 7 relative to the saw blade noses 50, 49, so that the inner end faces 461 of the collar 46 axially load the lower end faces of the saw blade noses 49, 50 and further displace said noses axially upwards until the saw blade clamping end 5 22 rests centrally in the conical bore 33. The saw blade 23 is thereby secured in a centred and prestressed manner against release from the mechanism 20.

Figure 4 shows a clamping sleeve 121, which is arranged so as to rotate about a lifting rod axis 119 and functions according to the embodiments according to Figure 2. The clamping sleeve 121 supports a radial cam 132, which is pivotable together with the clamping sleeve 121 about the axis 119 via a slide 129. To this end, the slide 129 is mounted in an upper and a lower slide guide 180, 182 so as to be displaceable against the force of a restoring spring 184 constructed as a compression spring. The slide guides 180, 182 and the restoring spring 184 selected as a compression and/or tension spring are non-displaceably secured in a gearing housing, not illustrated.

Figure 5 is a plan view according to Figure 4, the clamping sleeve 121, the slide 129, the cam 132 and the restoring spring 184 constructed as a compression spring being clearly recognisable. The path of movement of the slide 129 is indicated schematically by broken lines.

Figure 6 illustrates a clamping sleeve 221 with a lifting rod axis 219, a cam 332 and a restoring spring 284, which are coupled via a rib-like, double-arm lever 227, which is pivotable about a pivot axis 230 and comprises a push lever 228 and a trigger 229, with a restoring spring 284. The schematically illustrated abutment 2301 of the pivot axis 230 is fixedly secured to the symbolically illustrated gearing housing 214. An actuation arrow 185 shows the direction of action of the finger of the operating end. A 8 movement arrow 287 shows the pivoting direction of the clamping sleeve 221 or of the trigger 229.

Figure 7 is a plan view of the clamping sleeve 221 and shows the cam 232 in its original position in broken lines and in its release position adjusted by the lever 227 in continuous lines. Also visible are the push lever 228, the trigger 229 and the pivot axis 230 with the symbolically illustrated abutment for the pivot axis 230 on 10 the gearing housing 214.

Figure 8 shows a clamping sleeve 321, which is pivotable with its cam 332 about the lifting rod axis 319 in order to release or clamp the saw blade, not shown.

is A traction cable 327 serving as actuating means is articulated to the cam '32 and guided over roflers 330, 3301, which are fixed to the housing 314 so as to rotate. The traction cable 327 can be actuated via a slide lever 20 329 guided in the wall of the housing 314.

Figure 9 is a side view of the clamping sleeve 321, its upper stroke position being shown in continuous lines and its lower stroke position in broken lines. it can be seen that the traction cable 327 can follow the movement of the clamping sleeve 321 as a result of its flexibility without requiring the presence of joints.

A restoring spring can be provided for the traction cable 327, but is not absolutely necessary in the present case. Its function can be fulfilled by the torsion spring for restoring the clamping sleeve 321 - corresponding to the torsion spring 42 in Figure 2. However, it is easily possible to effect a length compensation of the traction cable 327 according to the stroke position of the clamping sleeve 321 by means of a separate restoring spring, so that 9 the operation of the traction cable is made smoother as a result of the reduced play in its length.

Figure 10 shows a jigsaw 410 with a gearing housing 414. Viewed from below, a lifting rod 418 emerges from the gearing housing 414. The lifting rod 418 is axially displaceably mounted in the gearing housing 414 in a lower and an upper lifting rod mount, not shown. At its lower end, the lifting rod 418 supports a mechanism 420 having a clamping sleeve 421 for clamping and centring a saw blade 423.

A vertically adjustable slide 429 is guided so as to move vertically up and down in a slide guide 480 on the gearing housing 414 of the jigsaw 410 according to the actuation arrow 485. The slide 429 supports a nose 430, which engages in or is engaged by an inclined slot 488 in a switching sleeve 489, which is mounted on the gearing housing 414 so as to pivot about the lifting rod axis 419.

The switching sleeve 489 is connected via torsion spring means, not shown, to the gearing housing 414 and is supported with its inner radial cam 490 against an external, radial cam 432 of the clamping sleeve 421 which encloses the saw blade 423.

Figure 11 is a cross section according to the arrows A-A in Figure 10 through the mechanism 420 for clamping the saw blade 423, the clamping sleeve 421, its cam 432, the lifting rod axis 419, the nose 430 of the slide 429 being recognisable as details without the slide 429 and without the slide guide 480, the switching sleeve 489 and its cam 490.

Figure 12 is a side view of the switching sleeve 489 with the inclined slot 488 for engaging the nose 430.

When the slide 429 is displaced downwards according to the actuation arrow 485, the switching sleeve 489 is displaced to the left in the drawing, following the movement arrow 486. The cam 490 of the switching sleeve 489 comes to rest against the cam 432 of the clamping sleeve 421 and displaces the latter in the direction of the movement arrow 486. The clamping sleeve 421 thereby rotates into the release position for the saw blade 423. When the slide 429 is released, the switching sleeve 489 returns in the opposite direction to the movement arrow 486 following the force of the tension spring 484, back into its original position and thereby displaces the slide 429 upwards via the nose 430.

Figure 13 is a schematic illustration of the clamping sleeve 521 with a radial cam 532 in a view from below or above. Supported against the cam 532 is a nose 530, which belongs to an adjusting member 589 which is pivotable on slide guides 581 about a lifting rod axis 519. On the side remote from the clamping sleeve 521, the adjusting member 589 supports radial toothing 592. The counter toothing 594 of a linear slide 529, which is constructed as a toothed rack and can be manually actuated via a push button 528, engages in the radial toothing 592. The slide 529 is guided on slide guides 580, 582 so as to be axially displaceable in the direction of the actuation arrow 585.

When the slide 529 is displaced in the direction of the actuation arrow 585, the adjusting member 589 is rotated about the lifting rod axis 519. The nose 530 thereby drives the radial cam 532 together with the clamping sleeve 521, which rotates into its position for releasing the saw blade.

Once the slide 529 has been released, the adjusting member 589 is moved back into its starting position by the restoring spring 584 and thereby drives the slide 529. The 11 nose 532 and the clamping sleeve 521 remain in their rotary position until a locking mechanism according to Figure 2 is released by the insertion of a saw blade. The clamping sleeve 521 then returns to its clamping position.

Figure 14 is a further plan view of a clamping sleeve 621 which is rotatable about a lifting rod axis 619 and supports a radial cam 632. A nose 630 of an adjusting member 689 opposes the radial cam 632. The adjusting member 689 is displaceably guided along a slide guide 681. A driving nose 696 of a linear slide 629 having a push button 628 engages in the adjusting member 689, the linear slide 629 being axially displaceably guided on fixed slide guides 680, 682 of the gearing housing, not shown.

is A restoring spring 684 is supported between the end of the slide 629 and a fixed part of the gearing housing which is not illustrated. When the slide 629 is displaced axially, its driving nose 696, travelling along a straight path, drives the adjusting member 689 along its curved path, the adjusting member moving the radial cam 632, via its nose 630, and therefore moving the clamping sleeve 629 into its release position. When the push button 628 is released, the slide 629 is displaced back into its starting position by the restoring spring 684. Via its driving nose 696, the slide 629 thereby drives the adjusting member 689 back into its original position.

Figure 15 shows a clamping sleeve 721 with a radial cam 732, which is rotatable and displaceable about a lifting rod axis 719. Supported against the cam 732 is a nose 730 of an adjusting member 789, which is displaceably guided along a curved path on a slide guide 781. The adjusting member 789 is constructed as a toothed rack on its side facing the observer. Engaging in its toothing 789' is a bevel gear 798, which is rotatably rigidly connected to a radial gear 7981 on a common rotary axle. The rotary axle 12 of the bevel gear 798 is fixedly connected to the gearing housing, not illustrated. Engaging in the toothing of the radial gear 7981 is the toothing 7291 of a toothed rack acting as a slide 729, which is axially displaceably guided on slide guides 780, 782. The slide 729 supports a push button 728. Opposite the push button 728, a restoring spring 784 is supported against the free end of the slide 729 and is supported with its rear side against the gearing housing 714 which is illustrated schematically.

When the slide 729 is displaced against the force of the restoring spring 784, the bevel gear 798 rotates with the radial gear about its fixed axle. In so doing, its teeth drive the adjusting member along the slide guide 781. By means of the nose 730, the cam 732 is rotated together with the clamping sleeve 721 into its position for releasing the saw blade.

When the slide 729 is released, it moves, following the force of the restoring spring 784, back into its original position. In so doing, it rotates the bevel gear 798. As a result of the rotation of the bevel gear 798, the adjusting member 789 is also displaced back into its original position. By appropriately selecting the gear ratio of the radial gear 798' and the bevel gear 798, it is possible to achieve a particularly operator-friendly stepup or step-down in order to actuate the clamping sleeve 721.

In a further embodiment of the invention, not illustrated, the clamping sleeve supports a bevelled face which is arranged in the path of movement of a pushrod, which is supported by a slide and is displaceable parallel to the lifting rod. The clamping sleeve is rotated via this bevelled face when the latter is contacted by the pushrod during the displacement of the slide.

13 It should be noted that the clamping sleeve in all embodiments is moved up and down with the lifting rod, so there is a plurality of stop positions in which the clamping sleeve needs to be accessible for the engagement 5 of the actuating element.

In addition, it should be noted that, depending on the selected saw blade strength, the clamping sleeve can adopt different rotary positions in which it also needs to be accessible by the actuating element.

In an embodiment of the invention which is not illustrated, a clamping sleeve supports a bevelled face, which is arranged in the path of movement of a cam which is displaceable parallel to the lifting rod, the bevelled face acting as an inclined plane in the path of movement. When the cam is displaced, it contacts the bevelled face of the clamping sleeve and thereby rotates the clamping sleeve.

14

Claims

1.

is A hand-guided jigsaw machine (10) with a lifting rod (18), which is guided in an upper and a lower lifting rod bearing and at its lower end supports a clamping mechanism (20) for clamping the saw blade (23), the clamping mechanism comprising a clamping sleeve (21; 121; 221; 321; 421; 521; 621; 721; 821), which at its free, lower end comprises a radially inwardly projecting collar (46), which is axially supported in the clamping position against noses (49, 50) of the clamping end (22) of the saw blade (23) and thereby clamps said end, actuating means (27) being provided, which are mounted on the housing for rotating the clamping sleeve (21; 121; 221; 321; 421; 521; 621; 721; 821) into its release position, characterised in that the clamping m-echanism. (20; 420) supports locking means (53', 541), which secure the clamping sleeve (21; 121; 221; 321; 421; 521; 621; 721; 821) relative to the lifting rod (18) in the release position for the saw blade (23) and release the clamping sleeve (21; 121; 221; 321; 421; 521; 621; 721; 821) again with the insertion of the saw blade (23) into the clamping mechanism (20), so that the actuating means (27) can only be brought into driving engagement with the clamping sleeve (21; 121; 221; 321; 421; 521; 621; 721; 821) in one actuating direction, i.e. from the clamping position into the release position, from which position the actuating means (27) automatically disengages from the clamping sleeve (21; 121; 221; 321; 421; 521; 621; 721; 821) and moves back into its original position.

A jigsaw machine according to claim 1, characterised in that a slide (29) acts as rotary actuating means (27) and on its path of movement drives a radial cam is 3.

is 5.

(21') of the clamping sleeve (21; 121; 221; 321; 421; 521; 621; 721; 821) so that the latter is rotated.

A jigsaw machine according to claim 1 or 2, characterised in that the slide (329) is coupled via traction means (327), more particularly a traction cable, with the clamping sleeve (321).

A jigsaw machine according to claim 4, characterised in that traction means constructed as a traction cable (327) is wound at one end around the clamping sleeve (321) and at the other end is secured to the slide (329).

A jigsaw machine according to claim 2, characterised in that the slide (429) is mounted so as to be fixed to the frame but displaceable parallel to the lifting rod (418) and engages with a nose (430) in an inclined groove (488) of an adjusting member (489), more particularly a switching sleeve, which is arranged on the housing and is mounted so as to be rotatable about the clamping sleeve (421), so that when the slide (429) is displaced, the adjusting member (489) is rotated and thereby drives the clamping sleeve (421).

A jigsaw machine according to claim 5, characterised in that the adjusting member (489, 589, 689, 789) is mounted on an annular guide so as to be pivotable about the clamping sleeve (421, 521, 621, 721).

A jigsaw machine according to claim 2, characterised in that the slide (529) is constructed as a toothed rack (529), whose toothing engages in toothing of the clamping sleeve (521).

8. A jigsaw machine according to claim 7, characterised in that the adjusting member (789) constructed as a 16 is toothed rack engages with its toothing (7891) in a gear (798) which is rotatably mounted on the housing and is coupled with the slide (729) provided with further toothing (7291).

A jigsaw machine according to claim 8, characterised in that the gear (798) cooperates via a bevel gear (798) with the further toothing (729') of the slide (729) constructed as radial toothing.

10. A jigsaw machine according to claim 1, characterised in that the actuating means is constructed as a pivot lever (27, 227), which acts with its free end upon the radial circumference of the clamping sleeve (21; 221), more particularly acts upon a radial cam (211, 2211) of the clamping sleeve (21, 221).

IL Any of the jigsaw machines substantially as herein described with reference to the accompanying drawings.