FR2735062A1 - JIG SAW WITH BLADE, THE BACK OF WHICH HAS Ripples AS WELL AS A BLADE FOR SUCH A SAW - Google Patents

Abstract

Jigsaw comprising a saw blade (22) performing a reciprocating motion; this blade is carried by a drive rod (14) and rests by its back (26) against a guide roller (32). The outline of the back (26) of the saw blade has a corrugated portion (28).

Description

State of the art.

  The invention relates to a jigsaw comprising a saw blade performing a reciprocating movement, this blade pressing by its back against a guide roller as well as a blade for such a saw. According to document GB-A-1 406 281 there is known a jigsaw whose blade has a back with recessed parts; this back rests against a guide roller. So,

  a transverse race is combined with each longitudi-

  nal of the saw blade, as soon as the recessed area of the saw blade arrives on the guide roller following the non-recessed area. This allows the side with the teeth of the saw blade, during its longitudinal stroke, to change its

  distance from the action line of the tool; that if-

  means that during the longitudinal stroke the blade either penetrates deeper into the tool or goes empty outside the line of action of the tool. Therefore, the constraint exerted

  on the blade of the tool in its longitudinal zones is irre-

  regular: the toothed area close to the fixing tail, pre-

  feeling a great rigidity, is more strongly stressed than

  the entry area close to the tip of the blade and the ri-

  gidity is less. This increases the life of the saw blade but the manufacturing costs are higher than

  the advantage given by such a saw blade.

Advantages of the invention.

  The present invention relates to a jigsaw characterized in that the outline of the back of the saw blade

  comprises at least one and preferably several undulating cavities

  protruding bores or bosses, which during the back and forth movement of the saw blade rolling against the guide roller

  provide pendulum drive.

  The jigsaw according to the invention offers the advantage of making it possible to saw more quickly, the evacuation of chips

  being effectively ensured by permanent furnishings pro-

  evoked by the many rapid transverse movements during

of a longitudinal stroke.

  According to other advantageous features of the invention:

  - the cavities or bosses have a radius of curvature greater than

  laughing at that of the guide roller against which they rest. - The cavities or bosses have a radius of curvature smaller or equal to that of the guide roller against which they rest. The invention also relates to a saw blade for such jigsaws, this blade being characterized

  in that the contour of the back of the saw blade comprises at least one and preferably several undulating cavities or bosses

  the. According to other advantageous characteristics - the cavities or bosses have a greater radius of curvature

  than that of the guide roller against which they are leaning.

  - the cavities or bosses have a smaller radius of curvature

  than that of the guide roller against which they are leaning.

  - The cavities or bosses which follow one another in the direction of translation of the blade have the same depth or the same relief.

Drawings.

  An exemplary embodiment of the invention will be shown

  crit below in more detail using the accompanying drawings in which: - Figure 1 is a side sectional view of the front area of a jigsaw according to the invention, - Figure 2 shows a blade saw for a

like a jigsaw.

  Description of the exemplary embodiment.

  According to Figure 1, a jigsaw 10 has a support plate 12 and a drive rod 14 guided in a high translation bearing and a low translation bearing 16, 18. At its inner end, the drive rod 14

  carries a clamping device for the saw blade 20. This arrangement

  sitive receives and clamps the fixing end not shown

in detail of a saw blade 22.

  The saw blade 22 has a toothed side 24 facing forward in the direction of movement; on its opposite side the saw blade has a back 26. The back 26 of the saw blade has in its central area a wavy back 28 with several undulations and cavities. It rests in the guide groove 30 of a guide roller 32. As in the case of a pendulum movement, the drive rod 14 is applied by elastic means towards the guide roller 32 or against a support of roller 34, there is an elastic support without play between the

  saw blade 22 and guide roller 32. The hanged movement

  area of the drive rod 14 and of the guide roller 32

  communicates to the saw blade 22 a pendular movement

  side which is combined with an additional transverse stroke

  silent corresponding to the wavy back 28. This transverse movement occurs several times during a longitudinal stroke while the known pendulum stroke, integrated into the mechanism

  only occurs once per run

gitudinal.

  Figure 2 shows a saw blade 22 rotated about its longitudinal axis with respect to the saw blade 22 of Figure 1. The toothed side 24 of the saw blade 22 is turned to the right. The back 26 of the saw blade or the wavy part 28 of the back is turned to the left. At the upper end, according to the drawing, there is the tail 22 of the blade with its two lateral nozzles 23, 23 '. The distance between the lowest and highest point of the wavy part of the back

  bears the reference Q. This deviation Q defines the transverse travel

  dirty caused by the wavy profile of the saw blade 22 at

sawing course.

  The jigsaw according to the invention operates from the

  as follows: after starting the engine not shown

  felt using the on / off switch not shown, the saw blade 22 performs a back and forth movement along its longitudinal axis 19. As the corrugated part 28 passes at the bottom of the guide groove 30 of the guide roller 32 , a

  transverse stroke is applied to the saw blade 22 in function

  tion of the profile of the corrugated part; this cross-race

  dirty combines with the back and forth movement. We arrive at an oscillating attack of the teeth on the part; this accentuates the removal of material and thus increases the power of

  chopped off. The frequency of the transverse stroke varies proportionally

  at the frequency of the longitudinal stroke. Thus, an increase in the frequency of the longitudinal stroke results in an increase in the frequency of the transverse stroke. 5 Depending on the type of material, the back of the saw blade may have regular undulations or even undulations specially adapted, giving a

  Irregular transverse stroke Q according to the profile of the undulations-

  to act optimally on the removal of ma-

third.

Claims (4)

R E V E N D I C A T IONS   1) Jigsaw comprising a saw blade (22) performing a back and forth movement, this blade pressing by its back (26) against a guide roller (32), characterized in that the contour of the back (26 ) of the saw blade comprises at least one and preferably several undulating cavities or protrusions, and which during the back and forth movement of the saw blade (14) rolling against the guide roller (32) provide pendulum drive.   ) Jigsaw according to claim 1, characterized in that the cavities or the bosses have a greater radius of curvature   to that of the guide roller against which they rest.   3) Jigsaw according to claim 1 or 2, characterized in that the cavities or bosses have a radius of curvature smaller or equal to that of the guide roller (32) against which they bear. 4) Saw blade for jigsaw according to the preamble of claim 1, characterized in that the contour of the back (26) of the saw blade comprises at least one   and preferably several cavities or corrugated bosses.    ) Saw blade according to claim 4, characterized in that the cavities or bosses have a radius of curvature greater than   that of the guide roller (32) against which they rest.   6) Saw blade according to claim 4, characterized in that the cavities or bosses have a radius of curvature smaller than   that of the guide roller (32) against which they rest.   7) Saw blade according to any one of claims 4 to 6, characterized in that   the cavities or bosses which follow one another in the direction of translation of the blade have the same depth or the same relief.