-having the characteristics of Claim 1, has the advantage that the saw
blades can be easily and rapidly removed, without an auxiliary tool and without risk of injury, by means of an integral push-button in the housing.
In-addition, the saw blades are clamped in position by an articulated, elastic mounting so that the saw blade can move backwards and forwards within the sabre bar without strain and, consequently, with increased efficiency.
Further advantages are indicated by the characteristics contained in the dependent claims.
Drawing An embodiment example of the invention is explained in greater detail in the following description with reference to the associated drawing. Figure 1 shows a perspective view of an embodiment example of the sabre saw according to the invention, Figure 2 is an exploded view of a pair of saw 3 blades with support elements and transmission parts, Figure 3 is an enlarged schematic diagram of the support element with two clamping jaws showing the operation of clamping a saw blade into position and Figure 4 shows a side view of another embodiment example of a support element with only one clamping jaw.
Description of the embodiment example The sabre saw 10 shown in Figure 1 is comprised of a machine housing 11 with an operating handle 12 which includes an on/off switch 13, a bow- shaped auxiliary handle 14 and a sabre bar 15, connected to the machine housing 11, within which are guided two paired reciprocating saw blades 16, 17, which pass through an opening 18 in the machine housing 11.
Since, in Figure 1, the left-hand saw blade 17 is covered by the righthand saw blade 16 and is therefore not visible, for the purpose of rendering the description more intelligible the reference numbers for the saw blade 17 and those for the details which are explained below but are not visible are given in brackets.
At the sabre bar tip 19, located close to the saw blades (16, (17) on both sides of the sabre bar 15, there is a longitudinal slot 20, (21) within which the saw blades 16, (17) are guided, so as to be captivated, by means of projections 22, (23) which fit in the manner of sliding blocks. Located on the side of the machine housing 11 there is a push- button 24 for releasing the saw blades 16, (17) from the locking devices which are explained with reference to Fig. 3.
The sabre bar 15 is comprised of a central plate 25 carrying side plates 26, (27), the space between the latter serving as 4 a guide groove for the backs 28, 29 of the saw blades 16, (17).
The exploded view in Figure 2 shows the shape of the saw blades 16, 17 and their position relative to support elements 40, 41 and to transmission parts 42, 43. It also shows separable connections provided by means of fastening screws 44, 45 and screw holes 46, 47, 48, 49.
Indicated on the saw blades 16, 17 are the backs 28, 29 of the saw blades and, opposite these, the saw teeth 30, 31, the clamping ends 32, 33 with the U-shaped clamping recesses 34, 35, the inner faces 36, 37 and the outer faces 38, 39.
The clamping ends 32, 33 have angled bends, not illustrated in greater detail, by which they are bent outwards towards the -outer face 38, 39. These bends prevent contact between the clamping ends 32, 33 within the sabre saw 10. The inner faces 36, 37 of the saw blades 16, 17 guided within the sabre bar 15 bear against each other.
Figure 3 shows the top view of only one of the two support elements 40, (41) indicated in Figure 2. The support element 40 has a hollow interior and houses a slide piece 50 with a centering surface 51 located on the end facing the saw blade clamping end 32. The slide piece 50 is fixed by means of clamping pins 55, 56 to a pre-bent leaf spring 54, each end of which is clamped within the support element 40 into a clamping slot 52, 53 in the upper and lower wall of the housing. Mounted on the slide piece so by means of additional clamping pins 57, 58 is a locking device with clamping jaws 60, 61, on the ends of which are locking recesses 62, 63 and locking lugs 64, 65. Each of the clamping jaws 60, 61 bears against a slide stop 66, 67 which is fixed to the housing of the support element 40. The clamping end 32 of the saw blade 16 is illustrated to show the top view of the back 28 of the saw blade with the clamping recess 34.
The pre-bent leaf spring 54 is a spring mechanism, acting as a servo spring to move the slide piece 50 between its two end positions and to hold the slide piece 50 biased in its end position.
The slide piece 50 and the leaf spring 54 are shown in the opening end position, in which the clamping end 32 of the saw blade 16 can be inserted and clamped in position. The position of the inner and outer faces 36, 37, 38, 39 indicates that the saw blade 16 and the clamping device are shown as viewed from above the backs 28 of the saw blades. The clamping position of the leaf spring 54 is indicted by the broken lines. The slide piece 50 overlaps the clamping end 32 of the saw blade 16, extending over its clamping recess 34. Two openings 71, 72 are provided on the front part of the slide piece 50, in alignment with the clamping recess 34. The locking lugs 64, 65 pass through these openings into the clamping position, the openings 71, 72 serving as strainrelief devices for the clamping jaws 60, 61 and ensuring a long service-life of the chuck 59. They also serve to safeguard the chuck against accidental opening.
The second support element 41 shown in Figure 2 but not illustrated in Figure 3 has the same structure as the support element 40.
A further embodiment example of the invention shown in Figure 4 has essentially the same elements as in Figure 3. Accordingly, the reference numbers in Figure 4 correspond to those in Figure 3, incremented by the number 100.
The slide piece 150 differs from that shown in Figure 3 in that it is of a more elongated form. The chuck 159 has only one clamping jaw 160 and, consequently, only one slide stop 167, which is also constructed as part of the support element 140. In addition, Figure 4 is turned 900 relative to the 6 drawing in Figure 3, to show the top view of the outer face 139 of the saw blade 116.
To clamp the saw blade 116, the clamping jaw 160 is moved vertically towards the back 128 of the saw blade, whereas in Figure 3 it is moved vertically towards the faces 36, 39. A strain-relief device as in Figure 3 can be provided by openings in the support element 140 but for reasons of simplification this is not illustrated.
The pressure plate 169 of the chuck 159 extends out of the support element 140 to a point at which it can be reached from the outside either directly by the fingers or by means of levers, operated by the push- button according to Figure 1, which are not illustrated.
-The support element 140, together with the saw blade 116, has a stroke of about 50 mm. The levers actuated by the pushbutton must have a range of action which extends over the stroke length so that the chuck 159 can be unlocked in any possible stop position of the support element 140, which also varies in each case due to the indeterminate stop position of the motor and the transmission parts.
The saw blades of the sabre saw 10 being arranged in pairs, a second support element is provided. This is not described but is identical in structure to the support element 140.
To clamp the saw blades 16, 17, 116 into position in the sabre saw 10, the locking mechanisms within the support elements 40, 41, 140 are operated in the following manner, described with reference to the single saw blade 16, 116. The clamping end 32, 132 is first inserted into the opening 18, 118 of the machine housing 11, along the lower edge of the sabre bar 15. The clamping end 32, 132 meets the centering surface 51, 151 of the slide piece 50, 150, the latter being axially displaced together with the saw blade 16, 116. This displacement 7 requires the friction between the clamping jaws 60, 61, 160 and the slide stops 66, 67, 167 to be overcome, this being supported by the servo action of the leaf spring 54, 154. The clamping jaws 60, 61, 160 are swivelled towards the saw blade 16 until the locking lugs 64, 65, 164 enter the clamping recess 34, 134 of the saw blade 16, 116. When the slide piece 50, 150 has reached its end position, the locking recesses 62, 63, 162 of the locking lugs 64, 65, 164 lock into the slide stops 66, 67, 167 and thereby lock the locking lugs 64, 65, 164 within the locking recess 34 of the saw blade 16. In addition, the leaf spring 54, 154 also exerts a retentive force on the slide piece 50, 150 when the former is in its end position, towards the left. If the saw blade 16, 116 is then moved towards the "open" position, i.e., against the direction arrow 68, 168, the chuck 59, 159 cannot be opened, thus ensuring that the saw blade 16, 116 cannot fall out.
To release the saw blade 16, 116 from the clamping position, the clamping jaws 60, 61, 160 are first pressed inwards by outer actuating elements, not illustrated, which are operated by pressing the push-button 24 (Figure 1), until the locking recesses 62, 63, 162 pass under the slide stops 66, 67, 167, thereby undoing the locking action.
Pulling the saw blade 16, 116 against the direction arrow 68, 168 then enables the chuck 59, 159, together with the slide piece 50, 150, to slide into the,open" position. The chuck 59, 159 then springs open to release the saw blade 16, 116, the locking lugs 64, 65, 164 being released from the clamping recess 34, 134. The saw blade 16, 116 can then be removed, in the direction opposite to that in which it is inserted.
The locking lugs 64, 65, 164 can be pressed inwards into their release position by levers, not illustrated, which are rigidly mounted on the housing and operated by the push-button 24, so that the saw blade 16, 116 can then be removed as described.
8 The sabre saw 10 operates in the following manner. operation of the switch 12 starts the motor, not illustrated, which moves the saw blades 16, 17 backwards and forwards, guided lengthwise within the sabre bar 15. The inner faces 36, 37 of the saw blades 16, 17 bear against each other and, at the same time, the backs 28, 29 of the saw blades bear against the base of the guide groove within the sabre bar 15. The projections 22, 23 engage in the longitudinal slots 20, 21, providing for highly stable guidance of the saw blades 16, 17, particularly in the area of the sabre bar tip 19. If the saw blades 16, 17 bind in a cleft, when the sabre bar 15 is withdrawn from the cleft against the binding force they are retained securely captive within the sabre bar 15.
9 h Claims 1. Sabre power saw (10), comprising two guided saw blades (16, 17; 116), located within a sabre bar (15), capable of parallel reciprocating movement in opposite directions and each possessing a clamping end (32, 33; 132), which are coupled at the power transmission end through clamping devices (40, 41, 50, 59; 140, 150, 159) and comprise the saw teeth (30, 31), characterized in that the saw blades ((16, 17; 116) can be clamped in position without an auxiliary tool by insertion into the clamping devices (40, 41, 50, 59; 140, 150, 159), locking devices (59; 159) being capable of being interlocked with the clamping ends (32, 33; 132) as a result of axial insertion into the clamping devices (40, 41, 50, 59; 140, 150, 159), particularly split-chuck type clamping devices.
2. Sabre saw according to Claim 1, characterized in that the locking devices (59, 159) are comprised of one or more clamping jaws (60, 61; 160) located, so as to be capable of displacement, on a support element (40, 41; 140) and being elastically supported along a slide stop (66, 67; 166) and, upon displacement, particularly by the saw blade (16, 17) which is to be clamped in position, being capable of being swivelled in such a way that the slide stop - depending on the direction of displacement - engages in or is released from a clamping recess (34, 35; 134) on the correspondent clamping end (32, 33; 132).
3. Clamping device (40, 41, 50, 59; 140, 150, 159) in a mechanical saw (10) for interlocking the clamping end (32, 33; 132) of a reciprocating saw blade (16, 17) at a clamping 1 recess (34, 35; 134), characterized in that a support element (40, 41; 141) comprises a locking device (59; 159) with one or more clamping jaws (60, 61; 161) which, depending on the direction of displacement of the locking device (59; 159), are swivelled into the clamping recess (34, 35; 134) to effect locking or are released from the latter.
4. Clamping device according to Claim 3, characterized in that the clamping jaw (60, 61; 160) is capable of being spring-locked with strainrelief in the clamping position on the support element (40, 41; 140), particularly by a slide piece (50).
5. Clamping device according to Claim 4, characterized in that the locking device (59, 159) is carried by a spring (54; -154), particularly a bistable spring mechanism formed by a leaf spring (54; 154), within the support element (40, 41; 140).
6. Clamping device according to Claim 5, characterized ir that the locking device (59) is constructed as a split-chuck type part and has two clamping jaws (60, 61), the part (59) being carried by a slide piece (50) which supports and centres the clamping end (32, 33) during insertion and in that each of the clamping jaws (60, 61) can be locked against the support element (40, 41) in the clamping position with a locking recess (62, 63).
7. Clamping device according to Claim 6, characterized in that the splitchuck type part (59) is formed from a U-shaped leaf spring, on the ends of which are mounted the clamping jaws (60, 61) and pressure plates (69, 70), acting as clamping grips, which extend out of the support element (40, 41) in such a way that they can be externally actuated.
11 9. Either of the sabre power saws substantially as herein Ilescribed with reference to the accompanying drawings.
10. Either of the clamping devices substantially as herein described with reference to the accompanying drawings.