DE19925745A1 - Hand-held scroll saw, with upper arm carrying end casing on its end fitting round first abutment to hold end of saw blade - Google Patents

Abstract

The saw has a scroll saw blade (33) clamped between two arms (221, 222). The free end of one of the arms carries a transverse handle. The upper arm has an end casing (24) fitting round the first blade-clamping abutment (56). The lower arm carries a base casing on its free end, which fits round a second abutment (57).

Description

State of the art

The present invention is based on a hand-held Fretsaw according to the preamble of claim 1.

US 5,027,518 is a generic fretsaw known machine that is under construction of a manually operated Jigsaw is similar, with the typical U-shaped bracket one handle protruding downwards with a motor housing carries, with the back of the handle a switch for Control of the energy supply of the engine carries.

The known machine only has compared to manual fretsaws the advantage that the manual saw movement is eliminated without that further handling advantages would result from this.

Advantages of the present invention

The fretsaw machine according to the invention with the features of Claim 1 has the advantage that it is very light, convenient lies in the hand and can be controlled from the Is to be operated by operators.  

The handling security is improved in that the pistol-like base housing after the handle is extended to the rear and in the operating position on Supports the operator's forearm.

The fact that the arms of the U-shaped bracket by a multiple ches, in particular twice as long as the leaves saw blade, can handle relatively large workpieces can be machined to the center with a jigsaw, d. H. the maximum depth of cut in a board-like workpiece from the edge of which is relatively high.

The fact that the handle the on and off switch of the Mo this switch is particularly good, especially special with the index finger, manageable.

Because the base housing the motor and drive means for moving the jigsaw blade back and forth secured against dust and damage.

The fact that the upper arm of the bracket at its free end carries an end housing, the clamping and guide means to solve absorbable spans of the jigsaw blade, these are against Dust and damage especially secured.

The fact that the fretsaw a top of its base housing structured with grooves, flush with the other arm Carrying surface for supporting a workpiece is the Fretsaw especially checked and compared to the workpiece "trembling free" feasible, so that saw cuts as clean as with the ruler or the compass are executable.

The fact that the basic housing of the fretsaw ver clickable, detachable with a z. B. attached to a workbench bar saw table can be coupled, the handle of the saw  The jigsaw can be easily reached and gripped over the table with the saw table attached to it as a particularly precise po sitionable hand tools are used or at a workbench flanged saw table as a stationary device be used.

The fact that the base housing of the fretsaw over Longitudinal guides with the saw table, especially above Broken tongue and groove guides, can be coupled without play, the fretsaw can be inserted into the saw table from above be inserted and bayonet-like with this without Auxiliary tool can be combined.

The fact that the fretsaw from the table by Never that can be separated by pressing a latchable button, that is Solving the fretsaw especially without auxiliary tools quick and easy.

The fact that the fretsaw one parallel to the fretsaw blade-movable workpiece hold-down, which too The one to be worked on serves as a finger deflector Work piece especially well compared to the fretsaw trollable fixed, so that particularly precise saw cut as if drawn with a compass or ruler can.

The fact that the arms of the U-shaped bracket flat free En the have and each carry a leaf spring, are the Leaf springs for parallelogram guidance of the saw blade fully connected to the arms and a be particularly precise parallel alignment of the two leaf springs to each other possible.

Because the leaf springs unite at their free ends Wear a central slot in each end of the fretsaw  is detachably attachable, is a tool-free clamping of the jigsaw blade possible (positive, which is safer than the previously known positive clamping of Laubsä scroll by turning a wing nut).

The fact that the upper leaf spring is bent into a U-shape and with her lower leg so at the free end of the arm of the U shaped profile is attached, in particular riveted that the legs in the same direction with the free arm outwards white sen, with the curvature and the upper U-leg free are pivotable, an elastic is particularly inexpensive preloaded swing arm for a parallelogram type gearbox procure, whose counter-arm attaches to the lower arm te leaf spring forms and for which the saw blade the coupling is.

The fact that the lower leaf spring, in particular positive sig, via drive means, in particular via a connecting rod the motor can be coupled, the transmission of the An takes place driving force not directly on the saw blade, so that the Reversal of movement in the dead centers on the trajectory of the Saw blade is steamed.

The fact that the lower leaf spring at its free end punched, downwardly curved tab has an eyelet to engage the connecting rod is a particularly inexpensive permanent coupling between connecting rod and leaf spring possible.

Because the leaf springs each have one at their free ends have a groove running transversely to the slot Centered nipple of the saw blade and swiveling articulated is sustainable, especially with its cutting edge, that is Fret saw blade articulated in a parallelogram term gearbox can be coupled with the swinging leaf springs.  

The fact that the nipple bepes molded plastic stand and a square area pointing towards the saw blade have, which reach through the slot without play, are Clamping ends of the jigsaw blade safely centered and ge dampens compared to the leaf springs.

Because the U-shaped bracket is made of metal, esp special tube and that the base and end housing to the free Ends of the U-shaped profile made of plastic, in particular consist of half-assembled housing shells, is high stability for the abutment of the jigsaw blade with lightweight construction and ergonomic shape of the Laubsä machine realized.

drawings

The invention is based on an embodiment with belonging drawing explained in more detail.

Show it

Fig. 1 is a perspective view of the hand-woven according to the invention led jigsaw of front left,

FIG. 2 latched with a saw table jigsaw according to Fig. 1 from the front right,

Fig. 3 the fretsaw according to. Fig. 2 immediately before the locking of the anzuklipsenden saw table,

Fig. 4, the jigsaw from the front,

Fig. 5 is an isometric view from the right with disassembled or opened housing,

Fig. 6 shows the view. Fig. 5 from above with a tilted release position in clamping lever,

Fig. 7 shows the U-shaped bracket integral with the leaf springs as a single,

Fig. 8, the lower leaf spring with hinged clamping end of the blade leaf,

Fig. 9 is a bottom view of the lower leaf spring connecting rod,

Fig. 10, the clamping end of the blade leaf,

Fig. 11 shows the detail of the tension lever,

Fig. 12, the saw blade of a detail,

Fig. 13 is a sectional view of the saw table,

Figure 14 is an exploded perspective view of the saw bench machine. With the corresponding housing region of the Laubsägema,

Fig. 15 shows a detail of the cross section of the base housing with the coupled saw table,

Fig. 16, the inside view of the right half-shell of the Basisge housing and

Fig. 17, the left half-shell with the motor and Ge geared and

Figures 18 and 19 guide, for example., The upper leaf spring as trapezoidal corner.

Description of the embodiment

The fretsaw 10 shown in FIG. 1 consists of a pistol-like lower base housing 12 with a handle 13 projecting transversely downwards. From its exit area from the base housing 12 , the handle 13 is angled rearward. The rear contour of the handle 13 forms in the exit area from the housing 12 a concavely curved throat 14 , which is continued horizontally to the rear as the lower outer contour of the base housing 12 . The throat 14 nestles into the operating hand and lies on the thumb and index finger, for example, on it. The horizontally extending rear area of the base housing 12 is supported on the back of the hand and on the forearm of the operator and forms an extended lever and thus a particularly secure support when handling the leaf saw 10 .

The handle 13 carries a switch button 15 at the front for breaking or closing the circuit. The switch button 15 is framed by lateral out of the handle 13 , nasenar term projections 130 . From the bottom of the handle 13 emerges a power cord 16 for power supply to the motor 11 arranged in the interior of the base housing 12 ( FIG. 19).

Underneath the switch 15 , a setting wheel 17 of a speed control electronics of the motor 11 , not specified, is arranged on the handle 13 .

The base housing 12 consists of two longitudinally divided half shells 1201 , 1202 and carries at the top a plane, ship-like deck-like support surface 18 with longitudinal grooves 20 on which a workpiece 19 can be supported for processing.

The base housing 12 carries on both sides below a circumferential outer edge 68 two spaced-apart clamping clips 21 , of which only the two arranged on the left side can be seen.

A lower arm exits the base housing 12 to the rear 221 of a U-shaped bracket 22, which is made of bent tube and is tightly enclosed by the half-shells 1201 1202nd The lower arm 221 merges via a rearward-facing convex curvature into an upper arm 222 running parallel to the lower arm 221 . This upper arm 222 carries at its forward free end an end housing 24 which is fixed to the arm 222 via fastening screws 23 (FIGS . 5, 6) and which consists of two longitudinally divided housing shells 240 , 241 . The Endge housing 24 carries a tension lever 25 to be operated from above, the handle 127 of which can be gripped by a trough-like or notch-like Ver recess 242 with the finger of the operating hand and can be pivoted upward to open in the direction of the actuating arrow 26 .

At its rounded front end, the end housing 24 carries a workpiece hold-down 27 , which consists of two round sliding rods 28 , which are displaceably mounted in the end housing 24 relative to the lower housing 12 . The at the slide rods 28 protrude above the end housing 24 and are connected to each other by a U-shaped arc 281 . The slide rods 28 carry at their lower free end, which faces the support surface 18 , a Fußarti gene stop 30 , which extends parallel to the support surface 18 hoof iron-like backwards and thus forms a slot 29 open to the front, in which a fretsaw blade 33 , which with its row of teeth 32 ( Fig. 5, 6) points forward, since Lich and from behind or is secured against too far lateral or rearward deflection.

The workpiece hold-down 27 can be moved upwards out of its locking position after the push button 270 protruding frontally from the end housing is depressed.

The fretsaw blade 33 has two clamping ends ( Fig. 5, 6), which are designed as an injected plastic nipple 34 and the diameter of the saw blade 33 at its clamping ends is significantly increased, so that these can be hooked into fork-like abutments 56 , 57 ( Fig . 5, 6) and are tensioned.

The end housing 24 has in its front area below the push button 270 a slot-like mounting window 243 through which the nipple 34 designed Einspan nende of the saw blade 33 in its upper abutment 56 is a hanging. Corresponding thereto, the base housing 12, a head-mounting slot 35, is suspended by the lower clamping end of the saw blade 33 leaves in the form of a second nipple 34th

Fig. 2 shows the fretsaw 10 coupled from the top right with egg nem saw table 37 , the upper, flat support surface 137 is flush with the support surface 18 of the base housing 12 , the grooves 20 of the support surfaces 137 , 18 merge regularly.

The saw table 37 has a suction nozzle 38 that emerges at the front ( FIGS. 13, 14) and opens into a suction hole 39 at the top in the area of the support surface 137 , through which sawdust formed during sawing can be extracted when a suction hose 38 is attached to the suction nozzle 38 Vacuum cleaner or the like is connected.

The saw table 37 carries in its rear region a U-shaped into the support surface 137 leading downward through recess 40 which corresponds to the outer contour or the outer edge 68 of the support surface 18 of the housing 12 . The recess 40 carries on top of opposite sides longitudinal guides 69 , 70 , 73 ( Fig. 13), which enable a bayonet-lock-like latching of the base housing 12 of the fretsaw machine 10 in the saw table 37 and its play-free maintenance.

A locking button 42 forms a detent stop 43 which engages in a corresponding recess 1210 of the base housing 12 near the support surface 18 and releasably holds the base housing 12 and thus the fretsaw 10 relative to the saw table 37 .

The support surface 137 of the saw table 37 is passed vertically downwards from the outside equally spaced screw holes 44 , through which screws can be inserted, with which the saw table 37 can be screwed to a fixed base, for example a workbench or the like. In addition, the saw table 37 at its outer edge towards th clamping openings 71 ( FIG. 13) for the entry of a clamping jaw of a screw clamp, not shown, with which it can be fastened to a solid base.

The handle 13 protrudes below the saw table 37 , so that the fretsaw 10 with a mounted saw table 37 can be used together as a hand tool. So that the leaf sawing machine 10 is particularly easy to align relative to the workpiece 19 so that it is positioned at right angles to the saw blade 33 or the support surface 18 , 137 .

Fig. 3 shows the fretsaw 10 when loosening the saw table 37 or just before latching in or latching with it. It can be seen that the base housing 12 must be moved in relation to the saw table 37 parallel to its support surface 137 for final locking or releasing. Previously, the base housing 12 of the fretsaw 10 is to be inserted vertically from above into the recess 40 so that the clamping clips 21 and the outer edge 68 of the housing 12 come into engagement position with the corresponding guide springs 69 , 70 , 73 of the saw table 37 .

The arrows 46 , 48 show the direction for loosening or fastening the fretsaw 10 relative to the saw table 37 after the vertical insertion of the base housing 12 into the recess 40 .

Fig. 4 shows the front view of the fretsaw 10 , the cross-section for coupling to the saw table 37 being relevant, or the contour of the base housing 12 with the clamping clips 21 and the outer edge 68 being particularly clear. It can also be seen the mounting slot 35 or the Montagefen ster 243 and other details of the previous figures, without these being repeated.

Fig. 5 shows the front portions of the lower and upper arms 221 , 222 of the U-shaped bracket 22 without the base housing 12 , only with the left half-shell of the end housing 24 and the clamping mechanism for loosening or fastening the fretsaw blade 33 .

The lower arm 221 has a flattening 54 at its free end, to which a flat leaf spring 51 is fastened to fastening points 59 , in particular riveted. The leaf spring 51 carries at its abutment for the saw blade-clamping dienden free end 57 a central Ga belschlitz 58 for passage of the soul of the saw blade 33 and for holding the nipple 34th The free end 57 of the lower leaf spring 51 is at the extreme end down - and then backwards roof-like upwards - angled so that a throat 62 is formed in the transverse direction on the underside of the roof-like angle, into which a cutting edge is formed 61 of the nipple 34 ( FIG. 8) is supported in an articulated manner. After the roof-like area, the free end 57 of the lower leaf spring 51 sits in a short, flat area, to which an upwardly directed curvature 66 with a central longitudinal slot 660 closes, which is stamped or embossed one down arched tab 64 is formed. The curvature 66 and the La cal 64 together form an oval eyelet 65 for hanging egg nes 67 ( Fig. 9), which umwan delt the rotational movement of the motor in an up and down movement of the lower leaf spring 51 .

With the upper arm 222 of the bracket 22 , the left shell 241 of the end housing 24 is fastened by means of fastening screws 23 . The free end of the upper arm 222 forms a flattening 53 , on the upper side of which the upper leaf spring 50 is fastened, in particular riveted, to fastening points 59 . The upper leaf spring 50 extends as a to the right open nes U with its legs 501 , 502 outwards - like the free end 53 of the upper arm 222 , the lower, short leg 501 being attached to the arm 222 . The legs 501 , 502 are connected to one another by a curvature 52 .

The free end 56 of the upper, longer leg 502 of the leaf spring 50 is angled upward at the free end and then shaped V-shaped downward - mirror image of the outer end 57 of the lower leaf spring 51 and also forms a throat 62 therein, which also is passed through a central fork slot 58 beyond its center, so that the saw blade 33 is articulated with its other nipple 34 in the fork slot 58 or in the throat 62 of the V-shaped loading area, mirror image of the lower clamping end 34 of the saw blade 33 .

The arms 221 , 222 carry near their free ends through through holes 123 which extend transversely to the plane stretched by the bracket 22 and the passage of the fastening screws 23 for fastening the base or end housing 12 , 24 are used.

The upper leg 502 of the upper leaf spring 50 is assigned a tensioning lever 25 designed as a two-armed lever, which can be pivoted upward about a pivot axis 125 in the end housing 24 with its handle 127 , so that its cam 126 comes down and the upper leg 502 Leaf spring 50 takes to the lower arm 221 . For better engagement of the operator's finger, the handle 127 of the tensioning lever 25 is a tubular tube-like hollow body which is open to the rear and into which the operator with one finger, guided through a recess 242 in the outer contour of the housing 24 , conveniently engage and move upward can pivot.

Fig. 5 also shows the front portion of the end housing 24 with the workpiece holder 27 low. Its slide rods 28 carry the foot-like stop 30 with a central slot 29 below the end housing 24 . The horseshoe-shaped configuration of the stop 30 for lateral and rear gripping of the saw blade 33 can be seen . Likewise, the push button 270 can be seen , by pressing it down the locking of the hold-down 27 or the slide rods 28 can be released - upwards. The hold-down device 27 can be easily adjusted by pushing or pushing the sheet 281 with the operator's hand.

The position of the clamping lever 25 is in the clamping position Darge, wherein it dips into the concave recess and since it is flush with the outer contour of the end housing 24 . The upper leaf spring 50 is in the top dead center position, ie in the clamping position, only drawn in dashed lines and in the Lösepo position for changing the saw blade 33 drawn in continuous lines.

FIG. 6 shows the same details as FIG. 5, only the tensioning lever 25 pressing the handle 127 upwards and pivoting the cams 126 downward pushes the upper leg 502 of the leaf spring 50 downward. The concave recess 242 for flush immersion of the handle 127 within the outer contour of the end housing 24 becomes clear. In addition, an adjacent to the pivot axis 125 locking pin 129 of the housing shell 241 is shown, in which a hohlzy-cylindrical locking opening 128 of the clamping lever 25 can snap when reaching the release position. The saw blade 33 is released from the abutments or the free ends 56 , 57 of the upper and lower leaf springs 50 , 51 and removed to the front or ready for reinsertion into the abutments. For this purpose, the assembly window 243 in the end housing 24 or the mounting slot 35 ( FIG. 1) in the base housing 12 must be passed.

Fig. 7 shows the ge made of metal tube with a round cross-section U-shaped bracket 22 with the riveted leaf springs 50 , 51 , the free end 56 of the upper leaf spring 50 with the longitudinal fork slot 58 or with the throat 62 is particularly clear, as well as the flat, parallel alignment of the upper and lower flats 53 , 54 of the upper and lower arms 221 , 222 , without the other designated - already shown in the previous Fi gures - details to be repeated.

The curved upper leaf spring 50 and the straight lower leaf spring 51 are positively connected via hollow rivets to the respective flat end 53 , 54 of the arms 122 , 121 with the U-shaped bracket 22 . The advantage of the rivet connection is the vibration insensitivity to the dynamic loads on the leaf springs 50 , 51 . The bracket 22 serves as a rigid connecting link between the leaf springs 50 , 51 which oscillate in the base and end housings 12 , 24 and is particularly stiff against bending and torsion with a low dead weight.

In order to increase the stiffness of the bracket 22 in the saw blade stroke direction, it is advantageous to choose its cross section oval instead of round or to manufacture it from metal from carbon fiber material.

Characterized in that the lower leaf spring 51 is repeatedly arched in the area of its Wi derlagers 57 , its overextension in the area of the eyelet 65 is prevented, at which the driving force is transmitted from the motor via the connecting rod 67 to the leaf spring 51 .

The lower leaf spring 51 is neutral in its straight position parallel to the arm 221 and has a force increase of about 12 N via a deflection of 4 mm measured on the free end 57. The lower leaf spring 51 only serves to guide the saw blade 33 . In contrast to this, the upper, U-shaped leaf spring 50, due to its upward pretension, causes a uniform saw blade tension over the working stroke of the saw blade 33 . The leaf spring 50 is designed so that it applies approximately 50 N in the upper end position or in the top dead center (TDC). This force increases to approx. 65 N with a stroke of 8 mm until bottom dead center (UT) is reached, so that the tensile force during the working stroke of the saw blade 33 fluctuates between at least 50 N and a maximum of 65 N.

Instead of the upper, U-shaped leaf spring 50 , a trapezoidal, flat leaf spring can also be used. A sol che spring of the same spring characteristic also has the advantage of greater lateral stability, ie a lateral pivoting of the saw blade is prevented because the relatively low transverse bending stiffness of the curvature 52 of the leaf spring 50 is eliminated. In addition, the moving mass is reduced and riveting a straight, trapezoidal Fe with the arm 222 of the bracket 22 is easier than that of the U-shaped spring 50th In addition, due to the trapezoidal shape, the distribution of the bending stress during the deflection of the spring during the working stroke of the saw blade 33 is more uniform.

Fig. 8 shows in an enlargement the free end 57 of the lower leaf spring 51 with the fork slot 58 , the throat 62 , the tab 64 , the curvature 66 , the eyelet 65 and the slot 660 . It can be seen that the nipple 34 of the fretsaw 33 is pivotally mounted with its cutting edge 61 in the throat 62 in a pendulum-like manner, the fretsaw blade 33 having a square 36 adjoining the cutting edge 61 or its row of teeth 32 passing through the fork slot 58 . The plastic nipple 34 is stored in the slot 58 so that it continues after the cutting edge 61 in the form of a square 36 which extends far beyond the cutting edge 61 and encompasses the saw blade 33 on all sides. The square 36 also serves for the electrical insulation of the saw blade 33 from the motor or the transmission.

Fig. 9 shows a bottom view of the free end 57 of the unte ren leaf spring 51 , the fork slot 58 , the throat 62 , the tab 64 and the eyelet 65 and the longitudinal slot 660 can be seen in the hook-like connecting rod 67 which engages through the motor, not shown, is moved back and forth or up and down.

Fig. 10 shows the nipple 34, the cylindrically extending at the outermost end of the leaf blade 33 and toward the cutting edge forms by two roof-like bevels on the other nipple 34 61, from which the square portion 36 occurs, the saw blade, the leaves 33 free of play, against rotation in Fork slot 58 of the leaf springs 50 , 51 is supported.

Fig. 11 shows the detail of a two-armed lever designed tension lever 25, of which one arm of a hollow handle portion 127 and the other arm as a cam 126 is designed, between which the axis of rotation 125 is disposed.

Fig. 12 shows the detail of the jigsaw blade 33 with the clamping ends designed as nipples 34 , the roof slopes, cutting 61 and square areas 36th

Fig. 13 shows a spatial partial longitudinal section of the Sägeti cal 37 , the suction nozzle 38 , the suction hole 39 , the recess 40 , the locking button 42 with the detent stop 43 , the screw hole 44 and the grooves 20 can be seen. In addition, 12 serving as guide springs 69 can be seen as a longitudinal guide of the base housing, with interruptions 75 and side ramps 73 and on the outside rear an inlet opening 71 for the jaw of a screw clamp, for fastening the saw table on a base such as. B. workbench or the like.

The interruptions 75 of the guide springs 69 serve for the vertical entry of the lateral clamping clips 21 of the base housing 12 for reaching under the guide springs 69 and for lateral support on the ramps 73 .

The mode of operation of the bayonet-type clip-in system between the base housing 12 and the saw table 37 is again illustrated in FIG. 14, viewed obliquely from below in a partial side section. The guide springs 69 , their interruptions 75 , the wedge-shaped inwardly formed ramps 73 and the locking button 42 in the stop 43 are clearly visible. Also highlighted is the suction port 38 , the suction hole 39 and the recess 40, as well as explosively - in the viewing direction above - the side region of the base housing 12 with the clamping clips 21 and the upper outer edge 68 of the base housing 12 for reaching into the recess 40 of the saw table 37 .

Fig. 15 shows a cross-section of the base housing 12 with the saw table 37 further illustrates the bayonet-type mounting system between the base housing 12 and the SAE 37 getically. It can be seen how the guide springs 69 are supported laterally and vertically between the longitudinal outer edge 68, and the clamping clips 21st In this case, a guide groove 70 is formed between the clamping clips 21 and the outer edge 68 for the entry of the guide springs 69 . The ramps 73 , which are supported since against the clamping clips 21 and provide for a horizontally backlash-free mounting of the base housing 12 on the saw table 37, are also clearly recognizable.

Next, the grooves 20 in the support surface 18 of the housin 12 and in the support surface 137 of the saw table 37 he can be seen and that the handle 13 protrudes from the saw table 37 so far that it is easy to grasp with the operating hand.

The inside view of the right half-shell 1201 of the base housing 12 shown in FIG. 16 clearly shows the handle 13 , the throat 14 , one of the lugs 130 , the mounting slot 35 , the mouth 1211 for the passage and tight, ring-like gripping of the lower arm 221 and screw passage holes for the fixed coupling of the housing 12 to the bracket 22 .

In addition to FIG. 16, FIG. 17 shows the left half-shell 1202 of the base housing 12 with a mounted motor 11 and drives, the motor housing 110 forming elastic bearing points 111 via rubber rings 112 for the vibration-damped mounting of the motor 11 . A motor shaft 1103 carries a fan 113 and axially adjacent to it a pinion 114 which meshes with a counter pinion 115 . The counter pinion 115 is fixed on a crankshaft 116 , which carries a crank pin 119 at the free end for driving the connecting rod 67 .

FIGS. 18 and 19 show a variant to the upper U-shaped leaf spring 50 is a flat trapezoidal-shaped leaf spring 500 which has the same spring characteristic as the spring 50, but is easier to manufacture and easier riveting with the upper arm 222 of the bracket 22 allows. In addition, the trapezoidal shape of the leaf spring 500 ensures a more uniform bending stress distribution during the deflection of the spring end during the working stroke of the saw blade 33 than with the U-shaped leaf spring 50 .

In Fig. 18, the leaf spring 500 is relaxed, with the outer end 501 curved at the top dead center of the working stroke upwards, and bent down in Fig. 19, ie straight, in the tensioned state of the bottom dead center - before the upward stroke of the saw blade 33 - shown.

Claims (17)

1. Hand-held fretsaw ( 10 ) with a between two, preferably from a U-shaped bracket ( 22 ) formed th arms ( 221 , 222 ) at the ends of releasably tensionable saw blade ( 33 ), one of the arms ( 221 , 222 ) carries a handle ( 13 ), characterized in that the upper arm ( 222 ) carries at its end an end housing ( 24 ) which has a first abutment ( 56 ) for holding one end of the jigsaw blade ( 33 ) and clamping means ( 25 ) encompasses its releasable tensioning. 2. Fretsaw according to claim 1, characterized in that the lower arm ( 221 ) carries at its end a base housing ( 12 ) which engages around a second abutment ( 57 ) for holding the other end of the fretsaw blade ( 33 ). 3. Fretsaw according to claim 2, characterized in that the abutments for holding the clamping ends ( 34 ) of the leaves saw ( 33 ) from the ends ( 56 , 57 ) each have a leaf spring ( 50 ) arranged on the upper and outer arm ( 221 , 222 ) , 51 ) are formed. 4. Fretsaw according to claim 3, characterized in that the upper leaf spring ( 50 ) is U-shaped and has two legs ( 501 , 502 ), with one leg ( 501 ) at the end ( 53 ) of the upper arm ( 222 ) attached, in particular riveted ge, and that the legs ( 501 , 502 ) point in the same direction with the free end of the arm ( 222 ) to the outside. 5. Fretsaw according to claim 4, characterized in that the leaf springs ( 50 , 51 ) carrying ends ( 53 , 54 ) of the arms ( 122 , 222 ) are flattened. 6. Fretsaw according to claim 5, characterized in that the ends ( 56 , 57 ) of the leaf springs ( 50 , 51 ) serving as abutments carry a, preferably central, fork slot ( 58 ), in each of which a clamping end ( 34 ) of the fretsaw blade ( 33 ) can be detachably attached, the fretsaw blade ( 33 ) on the Ga belenden ( 56 , 57 ) of the leaf springs ( 50 , 51 ) parallel to the longitudinal axis up and down can be performed. 7. Fretsaw according to claim 1 or 2, characterized in that a two-armed lever ( 25 ) is used as the tensioning means for tensioning / releasing the fretsaw blade ( 33 ), one end of which, in particular by a finger of the operator under graspable, actuating means - and its other end than cam ( 126 ) for depressing the upper abutment ( 56 ) - is used. 8. Fretsaw according to one of claims 2 to 7, characterized in that the lower leaf spring ( 51 ), in particular in a form-fitting manner, can be coupled to the motor ( 11 ) via drive means ( 80 ). 9. Fretsaw according to one of claims 2 to 8, characterized in that the lower leaf spring ( 51 ) at its free end ( 57 ) has a, in particular punched, downwardly curved tab ( 64 ) which has an eyelet ( 65 ) for Engagement of a connecting rod ( 67 ) forms. 10. Jigsaw according to one of claims 2 to 9, characterized in that the lower leaf spring ( 51 ) at its free end ( 57 ) has a groove ( 61 ) which extends transversely to the fork slot ( 58 ) and in which a nipple ( 34 ) designed clamping end of the saw blade ( 33 ), in particular with its cutting edge ( 61 ) self-centering to form a swivel joint, can be supported. 11. Fret saw according to claim 1, characterized in that the base housing ( 12 ) is designed like a pistol and transversely downwards into a handle ( 13 ) whose rear contour forms a throat ( 14 ) in the transition to the angled base housing ( 12 ) in the operating position in the hand of the operator, vertically and horizontally clamping, nestles, the lower arm ( 221 ) emerging from the rear of the housing ( 12 ), arcuately upwards and forwards into the second arm ( 222 ), so that the convex side of the arched arch faces backwards. 12. Fretsaw according to claim 11, characterized in that the base housing ( 12 ) on the handle ( 13 ) then extends to the rear and serves as a forearm support. 13. Fretsaw according to claim 11 or 12, characterized in that the handle ( 13 ) carries a switch button ( 15 ) at the front. 14. Fretsaw according to one of claims 1 to 5, characterized in that the base housing ( 12 ) receives the motor ( 11 ) and drive means ( 80 ) for moving the lower leaf spring ( 51 ) up and down and thus the saw blade ( 33 ) . 15. Fretsaw according to one of the preceding claims, characterized in that the base housing ( 12 ), in particular re lockable, releasably with a, in particular attachable to a workbench, saw table ( 37 ) can be coupled. 16. Fretsaw according to one of the preceding claims, characterized in that the fretsaw ( 10 ) carries a workpiece hold-down device ( 27 ) which can be displaced parallel to the saw blade ( 33 ) and which also serves as a finger deflector ( 28 ). 17. Fretsaw according to claim 16, characterized in that the fretsaw blade ( 33 ) has two clamping ends which spring with thickenings, in particular in the form of nipples ( 34 ), serving as abutments free ends ( 56 , 57 ) of the blade ( 50 , 51 ) in the fork slot ( 58 ).