WO1983000836A1

WO1983000836A1 - Power sabre saw settable for forward or lateral sawing

Info

Publication number: WO1983000836A1
Application number: PCT/SE1982/000271
Authority: WO
Inventors: Gunnar Harry Lindkvist
Original assignee: Gunnar Harry Lindkvist
Priority date: 1981-09-07
Filing date: 1982-08-26
Publication date: 1983-03-17
Also published as: SE8105301L; EP0087433A1; SE427997B

Abstract

A powered sabre saw the saw blade (6) of which is removably fastened to a fastening plate (12) rigidly mounted to the free end of the reciprocating slide (10). The blade is removably clamped via a blade holder (13) which is screwable (16) to the fastening plate in two different, alternative working positions, one of which enables the holder and thereby the blade to be set for sawing straight forward, while the other enables the blade to be set for lateral sawing transverse the first-mentioned sawing direction. Two levers (28, 29) are arranged in the machine's gearbox, and one at a time these can be urged into gliding or rolling engagement with the rear edge (30) of the blade via a guiding groove for transferring swinging or pendular motion to the saw blade. Fixed and resilient guides (37, 38) are provided in the gearbox for guiding the slide in its reciprocating and pendular motion. The slide projects out from the gearbox through a bushing (42) settable in two working positions and turnably mounted in the gearbox, one setting position of the bushing being used for sawing straight forward and the other being used for sawing laterally. The fastening plate (12) and blade holder (13) are implemented such that the plane of the saw blade is at least generally coplanar with the front face of the gearbox when the blade is set for lateral sawing.

Description

Power sabre saw settable for forward or lateral sawing

The present invention relates to a device in powered sabre saws where the saw blade, adapted for swinging or pendular sawing is removably attached to a slide projecting from the gearbox of the machine and driven by the machine motor, said slide describing reciprocating stroke motion in its longitudinal direction.

Powered sabre saws of this kind are already known, and although they have been found to be very reliable and usable, they have however the large disadvantage that they can only be used for sawing straight forward, and further to this they do not permit sawing or working closer than a distance of about 5 cm to an edge or crossing wall. VJhen it is required to saw or work laterally, and then particularly close to a wall or some other obstruction, it is consequently not possible to use a machine of the conventional type, and other tools, such as chain saws or chisels, must be brought to use.

The primary object of the invention is to avoid said disadvantages, and to provide a new type of sabre saw with a saw blade fastening such that the blade can be set in two different working positions, one of which conventionally allows sawing straight forward in the direction of the machine's longitudina axis, while the second position permits sawing laterally, i.e. at an angle which is preferably a right angle to the longitudinal axis of the machine. Furthermore, lateral sawing shall be possible right up to a wall or other obstruction.

The said objects are achieved in accordance with the invention by a device characterized in that:. said end of the slide carries a settable blade fastening comprising a) a fastening plate rigidly attached to the end of the slide and b) a blade holder preferably swivel ably settable in two different working positions relative the fastening plate, on which it is mounted, the blade being removably clamped to said holder preferably by means of a screw mechanism, whereby the alternative mounting of the holder on the fastening plate enables optional sawing in a first direction (straight forward), or alternatively in a second direction (to one side) transverse the first direction: two levers are arranged at the gear box for transferring swinging or pendular motion to the saw blade, said levers being urgable one at a time into gliding or rolling engagement with the saw blade: fixed and resilient guides are arranged in the gearbox for guiding the slide in its reciprocating and pendular motions: and the lower portion of the slide situated closest to the blade fastening extends through a bushing turnably settable in two different setting positions and mounted in the gearbox to allow sawing in one of the sawing directions in either position.

In the dependent claims 2-10 there are disclosed preferred embodiments of the device in accordance with the independent claim 1 set forth above.

The invention will now be described and explained in detail with reference to an embodiment illustrated on the appended drawing.

On the drawing

Figure 1 is a side view of a power sabre saw provided with a device in accordance with the invention, with, the saw blade set for sawing straight forward;

Figure 2 is an end view of the machine in Figure 1 seen from the front (i.e. from the left in Figure 1);

Figure 3 illustrates the saw in a side view and partially in section when the saw blade is set for sawing laterally, i.e. at right angles to the sawing direction illustrated in

Figures 1 and 2;

Figures 3a , 3b , 3c , 3d and 3e illustrate details of the blade fastening to a larger scale;

Figure 4 is a partially sectional elevation through the forward part of the machine according to Figure 3;

Figures 4a and 4b illustrate details of the saw blade fastening to a larger scale; while Figure 4c illustrates an alternative embodiment of the pendulation levers for lateral sawing;

Figure 5 is a partial sectioned plan view through the forward part of the sabre saw, and finally

Figure 5a illustrates the settable slide bushing.

The electric motor-powered sabre saw illustrated on the drawing conventionally has a cylindrical gripping portion 1 including a motor housing, on the side of which there is placed a thumb operated switch 2. At its forward end the gripping portion 1 is connected to a gearbox 3, having a supporting handle 4 attached to its upper end and having a support plate 5 at its lower end, the plate being intended for support during sawing, when it bears against the portion where sawing takes place. The saw blade 6 projects out from the support plate 5 at a recess 7 in the forward edge 8 of the plate.

In order to achieve optimum cutting speed for sawing in different kinds of material, particularly materials of different hardness, the machine is provided in a manner known per se with a mechanism by which the swinging or pendular motion of the saw blade 5 can be controlled (but also completely disabled). Enabling and adjustment of the saw blade pendulation can also take place when the machine is in operation. Adjustment is made by turning a control arm 9 to the position O , I, II or III, which correspond to different degrees of pendulation.

As will have been seen from the general portion of the description, the invention relates to a new type of sabre saw in which the saw blade can be set either for sawing straight forward or alternatively for sawing laterally, particularly at right angles to the longitudinal axis of the machine, the the longitudinal axis of the cylindrical gripping portion 1 being intended here.

The description of the sabre saw will be confined below to the portions of the machine associated with the device in accordance with the present invention.

The saw blade 6, adapted for sawing with a pendular motion, is removably fastened to the lower end of a slide 10 projecting out of the gearbox 3. The machine's electric motor inside the gripping part 1 drives the slide 10 via a reduction gear (hot shown) in the gearbox 3. In operation the slide conventionally describes a reciprocating motion in its longitudinal direction.

Turning now primarily to Figures 3 and 4_S it will be seen that the sabre saw is depicted when the saw blade 6 is set for sawing laterally, i.e. at right angles to the geometrical longitudinal axis of the gripping part 1. On the other hand, Figures 1 and 2 depict the machine when the blade is set for sawing straight forward in the direction of the longitudinal axis of the gripping part.

The lower end of the slide 10 carries a settable blade fastening 11, comprising a fastening plate 12 (see Figures 4 and 4b) brazed or welded to the end of the slide, and a blade holder 13 removably fastened (see Figures 3a-3e and 4) to the plate, the saw blad being detachably clamped to the' blade holder 13 by means of a screw mechanism 14, the individual parts of which are apparent from Figure 3a. The blade holder 13 is provided with a hole 20 (see Figure 4a) for pivotably mounting it on the fastening plate 12 via a journalling pin 15 rigidly attached to, and projecting downwards from the plate, parallel to the slide 10. As will be seen from the illustrated embodiment, the central axis of the pin 15 is parallel to the central line of the slide but radially displaced therefrom.

For the selected blade setting the blade holder 13 is fixed to the fastening plate 12 by means of a fastening screw 16 threaded into the lower end of a central longitudinal bore (see Figure 4) in the hollow slide 10. The screw 16 is optionally screwable into either of two threaded holes 17 and 18 in the blade holder 13 (see Figure 4a), and of these holes one corresponds to the blade setting for sawing straight forward while the other corresponds to the setting for sawing laterally.

The blade holder 13 includes a fastening body 19 in which there are the pivoting hole 20, and the threaded holes 17,18 for the fixing screw 16, the body 19 also including a clamping piece 21 connected thereto by means of a screw mechanism which, when tightened, moves the clamping piece towards the body for clamping the blade against the blade holder. For this purpose, the fastening body 19 has a first oblique blade contact surface

22 for the fastening portion 27 of the saw blade, while the clamping piece 21 has an oblique second blade contact surface

23 for said fastening portion. The screw mechanism includes an externally (right-hand) threaded stud 24 on the body 19, a clamping piece 21 internally (left-hand) threaded in the hole for the stud 24, and a sleeve 26 provided at one end with a hexagonal hole 25 and having an external (left-hand) thread for coaction with the hole thread of the clamping piece and an internal (right-hand) thread for coaction with the threaded stud 24.

When the screw mechanism 26, 21, 24 is tightened, there is obtained wedged clamping of the saw blade fastening portion 27 against the blade holder 13, the portion 27 being provided with oblique contact surfaces complemental to the surfaces 22 and 23.

For transferring the pendular motion selected by the control arm 9 (which is synchronous with the reciprocating motion of the slide) to the saw blade, two levers 28 and 29 are disposed at the gearbox 3, one of these at a time being urgable into gliding or rolling engagement with the rear guiding edge 30 facing away from the toothed front edge of the blade. Each lever is operated for the respective pendular motion by one and the same rocker 31 pivotably mounted on the gearbox 3, its setting being regulated by means of the control arm 9.

The lever 28, giving pendular motion to the blade for sawing straight forward, has the form of a support rigidly attached to the rocker 31, said support having a guide groove which is V-shaped in cross-section for the guiding edge 30 of the blade 6. The lever 29, which gives the blade its pendular motion for lateral sawing (see Figures 3 and 4), on the other hand constitutes a portion of a rocker 33 pivotably mounted on the gearbox 3 and with two projections, of which one is the lever 29, while the other 34 is in contact with an upwardly facing surface on a portion 35 of the rocker 31, said portion 35 projecting forward in the longitudinal direction of the machine. The lever 29 formed with a finger-like support has at its end the same kind of groove or slot as the guide groove of the support 28.

At their ends coacting with the saw blade, the levers 28 and 2 may be provided with guide rollers 36 having a guide groove at the periphery thereof, instead of guide grooves for coaction with the guiding edge 30 of the saw blade. Such an alternative embodiment of the lever 29 is illustrated in Figure 4c.

For guiding the reciprocating and pendular motion of the slide 10 there are fixed and resilient guides disposed in the gearbox 3 (see Figures 3 and 4) . For guiding the slide when sawing forwards with pendular motion there are a pair of sprung guides 37, spaced side by side and parallel to the slide. For guiding the slide 10 in lateral sawing with pendular motion there are fixed guides 38, which are parallel to the guide. For transferring the guiding action of the guides 38 to the slide and for transferring the reciprocating motion to the slide there is a yoke 39 transverse the slide, and screwed to it, said yoke having rearwardly facing guide surfaces 40 sliding against for wardly facing surface s on guide edge portions 41 of the guid es 38. The lateral forces caused by sawing laterally with a pendular motion are taken up by the slides and the respective guide 38.

The lower part of the slide extends out through a bushing 42, turnably mounted in the lower part of the gearbox, for setting in two positions corresponding to the two sawing directions. When changing the setting of the blade from sawing straight forward to lateral sawing, the bushing 42 is turned an angle of 90°. The bushing 42 has a journalling opening 43 for the slide which is elongate (non-circular) in cross section, for allowing pendular motion straight forward and laterally, respectively, according as the sawing direction set (see Figure 5).

In order that the pendular motion of the saw blade shall be maintained when sawing laterally, there is a spring-biased pin 44 mounted in the wall of the gearbox (see Figure 4). The pin 44 extends at right angles to the slide 10 in through a slot in the turnable, settable bushing 42 and bears with its inner end portion 45 against the slide.

There is a risk of wrecking the saw blade, which occurs when the sabre saw is incorrectly set, i.e. when the blade is set for sawing forward at the same time as the slide bushing 42 is set for sawing laterally, or vice versa. To make such an incorrect setting impossible and to ensure that the settings of the blade and bushing correspond, the bushing is provided with a projection 46 (see Figure 5a) parallel to the slide, this projection being placed and formed such that the blade holder 13 goes free from it only when the blade and bushing are set for sawing in the same direction.

Alternatively, incorrect mutual setting of the blade holder 13 and bushing 42 can be prevented by forming the holder such that it only goes free from a sleeve in which the slide bushing is mounted when the blade and bushing are set for the same kind of sawing. Finally, while referring to Figure 3, it is particularly emphasized that the saw blade fastening, i.e. the fastening plate 12 and blade holder 13 , are so formed that the blade is in the same plane as the front face of the gearbox 3 when the blade is set for lateral sawing. Sawing can thus be performed directly adjacent a wall or other obstruction.

It should be noted that the invention is not limited to the embodiment described above and illustrated on the drawing, and that the invention embraces all the conceivable modifications and alternative embodiments falling within the scope of the following claims.

Claims

1. A device in powered sabre saws in which the saw blade (6), disposed for sawing with a swinging or pendular motion is removably attached to the end of a slide (10) projecting from the machine's gearbox (3) and driven by the machine motor, said slide in operation describing a reciprocating stroke motion in its longitudinal direction, characterized in that: said end of the slide (10) carries a settable blade fastening (11) comprising a) a fastening plate (12) rigidly attached to the slide end, and b) a blade holder (13) settable, preferably swivelably, in two different working positions relative the fastening plate on which it is mounted, the blade (6) being removably clamped to said holder (13), preferably by means of a screw mechanism, whereby the alternative mounting of the holder (13) on the fastening plate (12) enables optional sawing in a first direction (straight forward) or alternatively in a second direction (to one side) transverse the first direction; two levers (28, 29) are arranged at the gearbox (13) for transferring swinging or pendular motion to the saw blade, said levers being urgable one at a time into gliding or rolling engagement with the saw blade; fixed and resilient guides (37, 38) are arranged in the gearbox for guiding the slide in its reciprocating and pendular motions; and the lower portion of the slide nearest to the blade fastening (11) extends through a bushing (42) turnably settable in two different setting positions and mounted in the gearbox to allow sawing in one of the sawing directions in either position.

2. Device as claimed in claim 1, characterized in that the blade holder (13) is swivelably mounted at the fastening plate (12) on a journalling pin (15) projecting out from the plate, fixation of the blade holder in the desired working position being implemented by a fixing screw (16) screwed into the contiguous end of the slide (10), said screw being screwable into a threaded hole (17 or 18) in the blade holder (13) corresponding to the selected working position.

3. Device as claimed in claim 2, characterized in that the blade holder (13) includes a fastening body (19) in which are made the hole (20) for the pin (15) and the threaded holes (17, 18) for the fixing screw, the body also being provided with a first oblique blade contact surface (22) for the faste ning portion (27) of the blade, and a clamping piece (21) with a second oblique blade contact surface (23), said clamping piece being connected to the fastening body (19) by means of a screw mechanism (24, 21, 26) which, when tightened, urges the clamping piece (21) towards the fastening body so that both oblique blade contact surfaces (22, 23) are thereby moved towards- each other, and with a wedging action provide clamping of the fastening portion (27) of the blade (6) provided with complemental oblique surfaces to the blade holder (13).

4. Device as claimed in any of claims 1 - 3, characterized in that the lever for the saw blade swinging or pendular motion for sawing forward comprises a support (28) with a groove which is V-shaped in cross section or with a skew-cut slit with which a complementally formed rear edge portion (30) of the saw blade is in gliding engagement during sawing, and that the lever for the swinging motion during lateral sawing consists of a support like a finger (29) with the same kind of groove or slit as the first-mentioned lever (28).

5. Device as claimed in any of claims 1 - 3, characterized in that the end of each lever (28 and 29) coacting with the saw blad is provided with a roller (36) having a peripheral groove in which a complementally formed rear edge portion (30) of the saw blade (6) is in contact during sawing.

6. Device as claimed in any of claims 1 - 5, characterized in that in the side wall of the gearbox (3) there is mounted at right angles to the slide (10) a spring-biased pin (44), the inner end portion (45) thereof bearing against the slide projecting through a slot in the turnably settable bushing (42) surrounding the slide, said bushing having its journalling opening (43) for the guide elongate, as seen in cross section.

7. Device as claimed in any of claims 2 - 6, characterized in that the journalling pin (15) projecting from the fastening plate (12) is placed in the plate such that the central line of the pin is parallel to the central line of the slide but situated at a given radial distance therefrom.

8. Device as claimed in any of the preceding claims, characterized in that the guides in the gearbox include a pair of resilient guides (37) laterally spaced and parallel to the slide (10) for guiding the slide in sawing forwards with pendular motion, and a pair of fixed guides ( 38) laterally spaced and parallel to the slide, for guiding the slide when sawing laterally with pendular motion, and that a yoke (39) rigidly attached to the slide (10) e.g. screwed onto it, extends transverse the slide and is adapted for being in gliding contact with the guides on both sides of a plane of symmetry including the slide and the longitudinal axis of the machine.

9. Device as claimed in any of the preceding claims, characterized in that the turnable settable bushing (42) has an axially directed projection (46), placed and formed such that the blade holder (13) goes free from it only when the saw blade and bushing are set for the same kind of sawing, either sawing straight forward or laterally.

10. Device as claimed in any of the preceding claims, characterized in that the slide (10) is so disposed in the gearbox

(3) and that the saw blade fastening (11) is so implemented that the plane of the saw blade itself coincides with, or is closely adjacent, the plane of the front face of the gearbox (3) when the blade is set for lateral sawing.