CA1126134A - Cam mechanism for imparting orbital movement to the blade of a reciprocating saw - Google Patents
Cam mechanism for imparting orbital movement to the blade of a reciprocating sawInfo
- Publication number
- CA1126134A CA1126134A CA340,120A CA340120A CA1126134A CA 1126134 A CA1126134 A CA 1126134A CA 340120 A CA340120 A CA 340120A CA 1126134 A CA1126134 A CA 1126134A
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- CA
- Canada
- Prior art keywords
- saw
- blade holder
- blade
- carrier
- cam surface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
CAM MECHANISM FOR IMPARTING
ORBITAL MOVEMENT TO THE BLADE OF
A RECIPROCATING SAW
Abstract Of The Disclosure The jigsaw has a drive gear carrying an eccentrically mounted drive pin forming part of a Scotch-yoke mechanism for reciprocating the blade holder along a first path. Upper and lower bearing assemblies mount the blade holder for reciprocating movement along the first path and for pivoting movement; the lower bearing assembly is mounted for reciprocating movement along a second path transverse to the first path thereby to impart corresponding movement to the lower portion of the blade holder. The drive gear has an annular concentric cam surface arranged for engagement with the lower bearing assembly. A
resilient member engages the blade holder for urging the lower bearing assembly against the cam surface to cause reciprocation of such bearing assembly along the second path whereby a saw blade attached to the blade holder will trace out an enclosed path. An adjustment cam is provided to vary the stroke of movement of the lower bearing thereby to vary the shape of the path of movement of the blade.
ORBITAL MOVEMENT TO THE BLADE OF
A RECIPROCATING SAW
Abstract Of The Disclosure The jigsaw has a drive gear carrying an eccentrically mounted drive pin forming part of a Scotch-yoke mechanism for reciprocating the blade holder along a first path. Upper and lower bearing assemblies mount the blade holder for reciprocating movement along the first path and for pivoting movement; the lower bearing assembly is mounted for reciprocating movement along a second path transverse to the first path thereby to impart corresponding movement to the lower portion of the blade holder. The drive gear has an annular concentric cam surface arranged for engagement with the lower bearing assembly. A
resilient member engages the blade holder for urging the lower bearing assembly against the cam surface to cause reciprocation of such bearing assembly along the second path whereby a saw blade attached to the blade holder will trace out an enclosed path. An adjustment cam is provided to vary the stroke of movement of the lower bearing thereby to vary the shape of the path of movement of the blade.
Description
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Background Of The Invention The invention relates to a reciprocating saw, such as a jigsaw, equipped with a cam arrangement for developing orbital movement of the saw-blade holder and saw-blade.
It has long been known in the art that it is advantageous if the saw-blade is caused to traverse a closed path, such as an elliptical path. This has been achieved by imparting to the saw~blade or saw-blade holder a reciprocating movement in a direction transverse to the up and down reciprocating movement of the saw-blade holder. This trans-verse movement, resulting in orbital movement of the saw-blade, has been produced in the past by a variety of dif~erent mechanisms.
One such prior art apparatus is disclosed in Bauer U.S. Patent 2~o. 3,890,708 wherein a balancing weignt is con-figured as an elongated member and is driven by an eccentric separate from the eccentric driving the saw-blade holder. The balancing member has a cam surface formed at its lower end which en~ages a roller mounted on a ~rame holding the saw-blade holder. The frame is resiliently biased toward the cam ~ace o:~ the balancing member so that the reciprocating move-ment o the balancing, member produces a lateral reciprocating movement of the frame and therefore oE the saw-blade holcler.
Means are also provLded ~or adjusting the stroke of the lateral reciprocating movement. This prior art device requires a supplementary ~,econdary drive which contributes to inc'reased expense and complexity of construction. A further disadvantage , k r ~2~
in this arrangement is the limited path of orbital movement permitted since it-is necessary that the balancing member, which produces the la~eral reciprocatin~ movement, be reciprocated in exac~ly 18a phase angle relation with respect to the saw-blade holder.
Another form of prlor art mechanism :Eor imparting orbital mo~ement to a reciprocating blade includes a cam surface on the back face of the saw-blade, which surface rides on a roller to achieve the transverse reciprocal move-ment. Such an arrangement is shown in U.S. Patent No.
Background Of The Invention The invention relates to a reciprocating saw, such as a jigsaw, equipped with a cam arrangement for developing orbital movement of the saw-blade holder and saw-blade.
It has long been known in the art that it is advantageous if the saw-blade is caused to traverse a closed path, such as an elliptical path. This has been achieved by imparting to the saw~blade or saw-blade holder a reciprocating movement in a direction transverse to the up and down reciprocating movement of the saw-blade holder. This trans-verse movement, resulting in orbital movement of the saw-blade, has been produced in the past by a variety of dif~erent mechanisms.
One such prior art apparatus is disclosed in Bauer U.S. Patent 2~o. 3,890,708 wherein a balancing weignt is con-figured as an elongated member and is driven by an eccentric separate from the eccentric driving the saw-blade holder. The balancing member has a cam surface formed at its lower end which en~ages a roller mounted on a ~rame holding the saw-blade holder. The frame is resiliently biased toward the cam ~ace o:~ the balancing member so that the reciprocating move-ment o the balancing, member produces a lateral reciprocating movement of the frame and therefore oE the saw-blade holcler.
Means are also provLded ~or adjusting the stroke of the lateral reciprocating movement. This prior art device requires a supplementary ~,econdary drive which contributes to inc'reased expense and complexity of construction. A further disadvantage , k r ~2~
in this arrangement is the limited path of orbital movement permitted since it-is necessary that the balancing member, which produces the la~eral reciprocatin~ movement, be reciprocated in exac~ly 18a phase angle relation with respect to the saw-blade holder.
Another form of prlor art mechanism :Eor imparting orbital mo~ement to a reciprocating blade includes a cam surface on the back face of the saw-blade, which surface rides on a roller to achieve the transverse reciprocal move-ment. Such an arrangement is shown in U.S. Patent No.
2,946,358 to Bruck. This arrangement has the disadvantage ~hat specially made saw-blades are required Jigsaws are also known wherein the lateral movement ~or achieving orbital motion is obtained with the aid of a bell~crank lever actuated by the drive mechanism. The bell-crank engages the saw-blade to move the same in a horizontal direction while a Scotch-yoke mechanism simultaneously causes the blade to reciprocate in the up and down direction.
Jigsaws of this type are shown in a number of U.S. patents to Papworth, e.g., 2,781,800; 2,917,088; 2,931,402; and 2,984,757.
Although these Papworth mechanisms have proved generally satis~actory, they require a considerable number of moving parts which results ln increasedcost and complexit~.
In other forms of prior art constructions, various linka~e mechanisrns are associ.ated with eccentric drlves to bring about some form of orbi-tal movement, representati.ve U.S. patents are ~los. 2,705,980 and 2,879,815, both to Papworth and No. 2,737,984 to Bruck. These linkage arrange-ments are somewhat complex and do not permit ready adjustment or variation to the orbital paths of~movement.
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In another form of Papworth mechanism shown in U.S.
Patent No. 2,961,016, the reciprocal blade holder is pivotally mo~mted at its upper end. The drive mechanism includes two eccentrics which engage the blade holder intermediate its ends for reciprocating ~he latter along two paths transverse to each other thereby to achieve the orbital movemen-t. This mechanism does not permit imparting the transverse reciprocal movement in an optimurn manner since the eccentric for producing lateral movement of the blade holder must necessarily engage the latter at its longitudinal midpoin~.
The construction shown in this patent is further disadvantageous in that it does not permit adjustment to the path of orbital movement.
Orbital movement is achieved in the jigsaw shown in Leach et al U.S. Patent No~ 3,457,7g6 by providing a guide for the crosshead connected to the upper end of the blade holder; the guide is disposed at an angle and imparts rocking movement to the blade holder. The mechanism shown in thls patent is rather comple~ and is believed to be further dis-advantageous in that the blade holder is subjected to undue frictional forces.
Another orm of ~rior art construction for orbiting a jigsaw blade is shown in Naslund U.S. Patent No. 3,236,111, assigned to the asslgnee oE the present application. There, the crosshead at the upper end oE the blade holder is move-ably connected to the eccentric drive such that the crosshead may move relative to ~he drive pin in a direction axially of the latter. An inclined cam surface is mounted in the tool
Jigsaws of this type are shown in a number of U.S. patents to Papworth, e.g., 2,781,800; 2,917,088; 2,931,402; and 2,984,757.
Although these Papworth mechanisms have proved generally satis~actory, they require a considerable number of moving parts which results ln increasedcost and complexit~.
In other forms of prior art constructions, various linka~e mechanisrns are associ.ated with eccentric drlves to bring about some form of orbi-tal movement, representati.ve U.S. patents are ~los. 2,705,980 and 2,879,815, both to Papworth and No. 2,737,984 to Bruck. These linkage arrange-ments are somewhat complex and do not permit ready adjustment or variation to the orbital paths of~movement.
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In another form of Papworth mechanism shown in U.S.
Patent No. 2,961,016, the reciprocal blade holder is pivotally mo~mted at its upper end. The drive mechanism includes two eccentrics which engage the blade holder intermediate its ends for reciprocating ~he latter along two paths transverse to each other thereby to achieve the orbital movemen-t. This mechanism does not permit imparting the transverse reciprocal movement in an optimurn manner since the eccentric for producing lateral movement of the blade holder must necessarily engage the latter at its longitudinal midpoin~.
The construction shown in this patent is further disadvantageous in that it does not permit adjustment to the path of orbital movement.
Orbital movement is achieved in the jigsaw shown in Leach et al U.S. Patent No~ 3,457,7g6 by providing a guide for the crosshead connected to the upper end of the blade holder; the guide is disposed at an angle and imparts rocking movement to the blade holder. The mechanism shown in thls patent is rather comple~ and is believed to be further dis-advantageous in that the blade holder is subjected to undue frictional forces.
Another orm of ~rior art construction for orbiting a jigsaw blade is shown in Naslund U.S. Patent No. 3,236,111, assigned to the asslgnee oE the present application. There, the crosshead at the upper end oE the blade holder is move-ably connected to the eccentric drive such that the crosshead may move relative to ~he drive pin in a direction axially of the latter. An inclined cam surface is mounted in the tool
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housing and arran~ed in the path of movement of the cross-head; resilient means urge the crosshead lnto engagement with this inclined surface for rocking the blade holder thereby to achieve orbital mo~ement. Other prior U. S. patents showing similar construction are ~nders No. 3,269,197 and Brucker No.
3,204,470. These mechanisms, although generally satisfactory, impose undue frictional restraints to the blade holder. More-over, these prior art mechanisms do not readily lend them-selves to providing a means to adjust or vary the orbital 0 path of movement of the reciprocating saw blades.
Summar Of The Invention In view of the foregoing, lt is an object of an aspect of my invention to provide a reciprocating saw where-in the pendular movement of the saw-blade is achieved by a direct coupling to the drive means which does not require an additional eccentric. It is an object of an aspect of my invention to provide an arrangement wherein the transverse motion is applied to the saw-blade holder at a location spaced away from the saw-blade where it can not be contami-nated by the chips cut by the saw-blade.
It is an object of an aspect of my invention to provide a reciprocating saw which requires no specially conigured saw b].ades to achieve pendular motion.
It is an object of an aspect of my invention to provide a reciprocating saw wherein the shape of the enclosed path traced by the saw-blade during pendular motion is inde-pendent of the position of the saw-blade holder. It is an ob~ect of an aspect of my invention to provide a recipro-cating saw wherein the enclosed path traced by the saw~blade can be made to have a pre-determined shape.
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Various aspects of the invention are as follows:
A power operated reciprocating saw or-jigsaw comprising: a housing; an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis;
bearing means for pivotally mounting said saw-blade holder in said housing; drive means for reciprocating the saw ~:~
blade holder in the direction of said longitudinal axis; and rotatable non-eccentric cam means operatively connected to said drive means for imparting a reciprocating movement to said saw-blade holder transverse to the reciprocating movement in said direction of said longitudinal axis where-by a saw-blade attached to said saw-blade holder will trace out an enclosed path of predetermined shape.
A power operated portable jigsaw comprising: a 15 housing; a saw-blade holder for holding a saw-blade; bearing :
means for pivotally mounting said holder in said housing;
drive means for reciprocating said saw-blade holder in a substantially vertical direction, and, a cam arrangement for imparting a pendular movement to said saw-blade ho:Lder;
the cam arrangement including: a body rotatably mounted in said housing and operatively connected to said drive ~ ~
means, said body defining an axis of rotation; said body -having a cam surace in surrounding relation to said axis of rotation, said cam surface belng ormed on said bod~
to have a predetermined contour indicative of the shape o~
the pendulax path traced by a blade attached to said blade holder; and, translation means for translating the rota-tional movement of said cam surface into a reciprocating movembnt of said saw-blade holder in a direction trans-:
verse to said vertical direction whereby a saw-blade attach~
ed to said saw-blade holder will trace out said pendular path.
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A power operated portable jigsaw comprising: a housing; an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis;
drive means for reciprocating said saw-blade holder in a substantially vertical direction; a first pivot bearing mounted in said housing for slide:ably holding said saw-blade holder at one portion thereof; a second pivot bearing or slideably holding said saw-blade holder at the remaining portion thereof; a cam arrangement for 10. acting on said second pivot bearing to reciprocate the same transversely to said vertical direction thereby imparting a pendular movement to said saw-blade holder; the cam arrangement including: a body rotatably mounted in said housing and operatively connected to said drive means, said body defining an axis of rotation; cam surface means formed on said body for rotation therewith; and, trans-lakion means for translatiny the rotational movement of said cam 3urface means into a reciprocating movement of said second pivot bearing over a predetermined stroke lèngth in a direction transverse to said vertical direction whereby a saw-blade at~ached.to said saw-blade holder will trace out an enclosed pendular path.
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The power operated portable jigsaw, embodying my invention and show~L for purposes of illustration, includes a housing and an elongated saw-blade holder for pivo~ally mounting the elongated saw-blade holder in the housing. Drive means are included for reciprocating the saw-blade holder in a substantiallY up and dow~L direction. It is a feature of my invention to provide rotatable non-eccentric cam means operatively connected to the drive means for im~arting a reciprocating movement to the saw-blade holder transverse to the reciprocating movement in the uP and down direction.
According to a feature of my invention, the cam arrangement for imparting the transverse movement to the elongated saw-blade holder includes a body rotatably mounted ~:in the housing and operatively connected to the drive means.
The body defines an axis of rotation. A cam surface is formed on said body in surrounding relation to the axis of rotation.
The cam surface is formed to have a pre-determined contour in.dicative of the shape of pendular pa~h traced by a blade : attached to the blade holder.
Translation means translate the rotational move-ment of the cam surface into a reciprocating movement of the saw-blade holder in a dlrection transverse to the vertical direction whereby a saw-blade attached to the saw-hlade holder trace out the enclosed pendular path.
The translation meatL,s can lnclude a bearing slide-ably holding the saw-blade holder and mounted on the housing so as to be reciprocably movable over a predetermined stroke ::
, length in a direction transverse to said saw-blade holder. A
resilient member urges thebearinglnto engagement with the cam surface means whereby the bearing rides on the cam surface me-ans and reciprocally moves through its pre-determined strol~e len~th in response to Ihe ro~ational movemen~ of the cam sur-face.
By providing the above described cam arrangement, the reciprocal saw according to my invention achieves the advantage that a minimal number of parts are needed to provide the motion in the transverse direction and this eliminates the need for an additional eccenlric. The cam arrangement provides a cam surface where ~he ~osition of the cam surface with respect to the lo~er bearing of the saw-blade holder is continuously changing so that the carrier which is pressed against the cam surface moves in the horizontal direction and this provides the desired reciprocal movement in the trans-verse direction. In this way, the desired path traced by a point on the saw-blade can be changed by configuring the form of the cam surface as desired. By forming the rotating cam surface means on a body rotatably mounted in the housing of the jigsaw, the need for an additional eccentric mechanism and guide arrangement becomes unncessary.
In tL~e instant inventionj the lower bearing is slldeably mounted in the housing so as to enable the cam surface formed on the hub-l.ike member to coact therewith and be brought to bear thereagainst under the action o a resilient member such as a spring. In this ~ay, it is possible to' adjust 3~
the end position of the lower bearing, for example, with the aid of an eccentric shaft to thereby vary the stroke length.
The eccentric shaft achieves a continuous adjustment of the range of the stroke length of the transverse movement between a maximum and zero by shifting the end position of the lower bearing in the region of the cam surface of the hub member which acts on this bearing.
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Brief DescriPtion Of The Drawin~,s Figure 1 is a side view, partially in elevation and -partially in section, showing a jigsaw embodying the present invention;
Fi~ure 2 is a s~ction taken along the line 2-2 of Figure l;
Figure 2A is a section taken along the line 2A-2A
of ~igure 2 ~with the drive gear rotated 90 from the position shown in Figure l);
: Figures 3A, 3B and 3C illustrate several of the possible paths of movement of a jigsaw blade attached to a saw embodyin~ the present invention;
Figure 4 is an ~nlarged fron~ view of the drive gear including the annular concen-tric cam surface;
Figure 5 is a section taken along the line 5-5 of Figure 4;
Figure 6 is an enlarged, fragmentary sectional view primarily illustrating the means for varying the enclosed p~th of movement of the jigsaw blade;
Figure 7 is an enlargedl fragmentary side elevational view show:Lng a manually o~erated member for varying the enclosed path of orbital movement of the jigsaw blade;
Figure 8 is a section ~aken along the lin.e 8-8 of Figure 7; ' . -8-~.26~L3~
Figure 9 is an enlarged, fragmentary, front ele~ational view showing a modified construction for preventing rotation of the blade holder;
Figure 10 is a section taken along the line lO-10 of Figure 9;
Figure 11 is an enlarged, fragmen~ar7 view, partially in section, showing an alternate form of resilient means associated with the blade holder; and Figure 12 ls an enlarged sectional view showing an alternate form of the lower bearing assembly which is engaged by the concentric cam on the drive gear.
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~escription Of The Preferred Embodiments Of The Invention -Referring primarily to Figure 1, the present inven-tion is shown as embodied in a portable, electrically powered Jlgsaw, generally designated 10. The jigsaw includes a housing 11 having an opening 12 de~ining a handle portion 14.
A leg 15 is connected to the underside of the housing 11; the leg su~ports a shoe 16 of conventional construction. '~he shoe includes a bifurcated portion 17 receiving a jigsaw blade 18.
The housing ll mounts an electric motor 20 including ~an armature shaft 21, the latter having,at its outer end,a formation of gear teeth 22. The armature shaft 21 is rotatably received within a sleeve bearing 24. This sleeve bearing is mounted in an openin~ 25 formed in clam-shaped type gear case members 26 and 27.
The teeth 22 on the outer end of the armature shaft 21 are in meshing engagemen~ with an annular formation of eeeth 28 formed on a drive gear 30. m e drive gear includes a concentric opening 3I receiving a shaft 32. This shaft is rotatably received in a sleeve bearing 33, the latter being mounted in a bore 34 for~ed in the gear case members 26 and 27.
The drive gear 30 includes an eccentrlcall~ formed bore 3G mounting a pin 37. This pin mounts a roller 38 received within a channel 39 which is mounted in a notch for~ed in a blade holder 40. Thus, it is apparent that the roller 38, supported on the eccentrically mounted pin 37, cooperates with the channel 39 to form a Scotch-yoke ~ 3 mechanism for imparting reciprocal movement of the blade holder 40 along its longitudinal axis upon rotation of the drive gear 30.
The eccentrically mounted pin 37 and roller 38 would tend to create an lmbalanced situation for the drive gear 30.
However, such a situation is avoided by providing a suitable bore or recess (not shown) in the drive gear to act as a counterbalancing means.
The upper portion of the blade holder 40, which is circular in sross-section, is slideably received within the ` ; ~bore~41 of a spherical bearing member 42. This bearing member is swivelly mounted within recesses 43 and 44 formed in the gear~case members 26, 27 and another recess 45 formed in a ~front gear case member 46.~ Thus, it is apparent that the ~upper bearing 42 mounts the blade holder for both reciprocatlng movement and pivoting movement; this pivoting movement occurs about the axis 47.
~ The lower portion of the blade holder 40, also circular in cross-section, is slideably received within a bore 48 formed in a bearing member 49. This bearing member is suitably mounted in various guideways constituted by the walls of rece.sses Sl and 52 :~ormed in the gear case members 26 ancl 27, and by further guideways formed in a recess si in the Eront gear case 46, such that the bearing ~lember 49 may move in a reciprocal path ~rom left to right as shown in Flgure 1. That is to say, the lower bearing member 49 ~s mounted for reciprocal movement along a path which i8 trans-verse to the reciprocal path of movement of the blade holder ~; which results from rotation of the drive gear 30 through the agency of the Scotch-yoke mechanism.
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The amount of reciprocal rnovement of the bearlng 49 is quite small; in-this regard, a wall surface 54 in the recess 53 limits movement of the bearing in the fo~ard direction, i.e., to the left as viewed in Figure 1. The diameter of the bore 48 is sufficiently dimensioned, with respect to ~he diame~er of the blade holder 4~, such that the bearing 49 may reciprocate and impart corresponding reciprocal movement to the lower portion of the blade holder without binding against the latter. Therefore, the bearing 49 suppor~s the lower portion of the blade holder for both reciprocal movement and pivotal mo~ement; this pivotal move-ment occurs about an imaginary axis 55.
-~ Referring now primarily to Figures 4 and 5J the drive gear 30 has a concentric, annular surface defining a cam face 57. This cam surface is, ln the embodiment shown for purposes of illustration, planar and contained in a plane which is slightly inclined with respect to the axis of rotatLon of the drive gear. The high and low points o:f the cam, 57a and 57b, respecti~rely, are illustrated in Figure 5.
The phase angle ~ (see Figure 4) may be defined as the angle, measured in the direction of rotation of the drive ~ear, from the high points 57a of the cam to a radius containing the eccentricaLly mounted pin 37.
In the embodiment of the cam shown for purposes of i].lustrati.on, the cam is s~mmetr-lcal and the high and low points 57a and 57b are diametri.caLly opposed. It will be understood that it is within the scope of the present inven-tion to provide other non-symmetrical cam surfaces. In this regard, the particular shape of the cam surface is a matter .
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of choice to ob~ain the desired path of movement of the saw blade, all as will-become apparent from the following speci-fication.
The lower bearing 49 includes a cam follower surface 60 arranged for engagement with the cam face 57. A leaf spring ~l, suitably mounted from the gear case 46, engages the channel 39 on the blade holder 40 for urging the cam fol~ower face 60 into engagement with the annular cam face 57. When the cam face 57 is in engagemen~ with the cam follower surface 60 it will be apparent that the lower bearing member 49 ~ill reciprocate back and forth (left to right as seen in Figure 1) in response to rotation of the drive gear 30. As will be explained more fully below, such reciprocating movement of the lower bearing 49 will cause the saw blade 18 to ~race out the enclosed orbital path of movement shown in solid lines in Figures 3A, 3B and 3C.
The present invention includes means for varyi.ng or adjusting reciprocal movement of the lower bearing 49 for in turn varying the shape o the path of movement of the saw blade. To this end, the gear case members 26 and 27 rotatably mount a pin 64. This pin carries an eccentrically mo~mted cam surface 65 (Figure 6) arranged for enga~ement with a cam follower surEace 66 on the lower bearin~ 4~.
When ~he pin 64 is rotated for positioning the cam 65 in the position shown in Flgure 1, this carn will not be permitted to engage the cam iollower surface 66 on the bearing 49; thus, when the pin 64 is so positioned, full reciprocal rnovement of the bearing 49 will be permitted in which event .
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the saw blade will trace out the enclosed path of movement shown in solid lines in Figure 3C. If the pin 64 i~ rotated for positioning the cam 65 in the position shown in Figure 6, t~e la~ter will engage the cam ~ollower face 66 for holding the cam Eollower 60 out of e~gagement with the annular cam surface 57; when the cam 65 is in the position just described, the lo~er bearing 49 will not be permitted to reciprocate and the saw blade will simply reciprocate along a rectilinear path as shown by the broken line in Figure 3A. If the pin 64 is rotated for orienting the cam 65 between the two positions shown in Figures 1 and 6, the bearing member 49 will be reciprocated intermittently through a stroke, less than its full stroke, for modifying the enclosed path of movement of the saw blade through a variety of paths depending on the orientation of the cam 65. One such modified path of movement, to be rererred to in greater detail below, is shown in Figure In the embodiment of the invention shown for pur-poses of illustration, mears are provided for orienting the cam 65 in four dif~erent positions. In this regard, and now referring particularly to Figures 7 and 8, a lever 68 is secured to the pin 63 exteriorly of the housing 11. The lever 68, adapted to be manuall~ operated, includes a finger portion 63a in which a blind bore 69 is formed. A detent ball 70 is received in this bore and urged outward].y thereof by a coil spring 71. The detent ball. is adapted to be received in a plurality of recesses 72 formed in the hou;si.ng 11 for releasably holding the lever 68 in any one of its four positions.
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Assume the manuall~J operated lever 68 is positioned for permitting full reciprocating movement of the bearing 49.
With the lever 68 so positioned, the movement of the blade will be as depicted in Figure 3C. The blade 18 is shown in its fo~ardmost position in solid lines; the rearwardmost position of the blade is shown by broken lines. Considering a single tooth l~a, the -~ip of that tooth will occupy the Point A when the lower bearing is in its fo~ardmost position, i.e., when the cam ~ollower surface 60 is being engaged by -the cam 57 at its highes~ point 57a. As the blade moves upwardly, the same will retreat until the tip of the tooth 18a reaches the Point B, which is the most retracted (upper) position of ~the blade. The blade now changes its direction of movement resulting from the S~cotch-yoke mechanism and begins to descend, retreating until the tip of the tooth 18a reaches the Point C;
thls lS the~most re~reated position of the blade which occurs ~- when the cam point 57b is engaging the cam follower surface 60. As the drive gear continues to rotate, the blade continues to descend and at the same time begins to advance forwardly mtil the tip of the tooth 18a reaches the Point D. At this point, the blade changes directlon as a result of operation of the Scotch-yoke mechanism and begins to retract upwardly at the same time moving forwardly as a result of the annular cam 57.
The upward path oE movement ~rom Poin~ D to Point ~ represents the portion of the stroke used Eor cutting.
As mentioned above, the orbit adjusting cam 65 may be positioned to hold the cam follower surface 60 Otlt of engagement with the annular cam surface 57 at all times. In this mode of operation, the saw bl.ade~will simply reclprocate ~ ~ 2 ~ 3 ~
in a rectilinear path as indicated by the broken line in Figure 3A.
As also mentioned above, it is possible to orient the orbit adjus,ment cam 65 in one or more intermPdiate positions thereby to modify ~he orbltal pa~h of movement of the saw blade. ~ :
Figure 3B illustrates such modi~ied orbital movement occurring when the lever 6~ is located i~ onP of its intermediate positions. In this partial orbi.t set~ing, the cam follower : surface 63 will be engaged by the annular cam surface 57 from Point A to Point B. Thereafter, the adjustment cam 65 will prevent the cam surface 60 from following the cam 57, and consequently the blade path is rectilinear as indicated by the :broken line from Point B to Point C in Figure 3B. The blade ~; ~ will then change its direction of movement as a consequence :of the Scotch-yoke mechanism and will re-tract upwardly to : Point A. At this last mentioned point, the cam surface 57 will again engage the cam follower surface 60 such that the tip of the tooth 18a will follow the solid line position ~rom Point A uPwardly and then downwardly to Point B as shown in Figure 3B.
: In some instances, it may be desirable to use a lighter spring than the return spring 61 shown in the Figure 1 embodiment. Such a llghter spring may not be ade~uate to prevent rotation oE the blade holder 40. However, rotation o the bl.ade holder may be prevented by the alternflte con-struction shown in Figures 9 and 10. There, the blade hvlder 40' includes a longitudinally extending slot 75. The lower bearing member 49' carries a pin 76 which is slldeably ~ -16-~2G~34 received within the slot 75 thereby to prevent rotation of the blade holder 40'.
Figure 11 illustrates an alternate form of return spring which may be employed with the modiied construction shown in Figures 9 and 10. In the Figure 11 modification, the gear case 46' is provided with a recess 78, the walls of which constitute a guideway for the bearing member 49'. The recess 78 also receives a light coil spring 80; this sprlng engages the bearing 49' and acts to urge the latter agalns~
the cam surfaces 57, 65.
It may also be desirable to provide the lower bearing 49 with a cam roller for engagement with the annular cam surface 57. Such an alternate construction is shown in Figure 12 ~here the lower bearing member 49" is provided with a bore 82 which receives a pin 83. A roller 84, received within a cavity 86 formed in the bearing 49", is ro-tatably unted on the pin 83. The roller 84 rides on the cam surface 57 as permitted depending on the orientation of the adjustment cam 65.
In sum, the present invention includes an elongated saw blade holder 40, which holder defines a longitudinal axis.
The drive gear 30, along with the eccentrically mounted roller 38 and channel 39, constitute a Scotch-yoke mechanism for reciprocating the saw blade holder .in the di.rection of such longit:udi.nal axis. The 9aw blade holder 40 is pivotally mounted in the housing by the spherical bearing member 42 , f~ 2~3~
and by the bearing 49 (as a result of the clearance between the dia~eter of the bore 48 and the diamter of the blade holder 40). The annular cam sur~ace 57 constitutes a rotatable non-eccentric cam associated with the drive means and imparts a reciproca~ing movement to the saw blade holder transversely to the reciproca~ing movement of the holder along the latter's longitudinal axis whereby a saw blade attached to the blade holder will trace out an enclosed path of pre-determined shape.
The cam follower face 60 or roller 84, as the case may be, constitutes translation means 'or translating rotational movement of the cam surface 57 into reciprocating movement of the saw blade holder in a direction transverse to the vertical longitudinal movement of the saw blade holder.
It should also be noted that the lower bearing 49 acts as a carrier in that it slideably supports the blade holder and is also mounted in the gear case members 26, 27 and 46 so as to be reciprocally moveable over a pre-determined stroke in a direction transverse to the longitudinal movemen~ of the saw blade holder. Of course, the cam 65 constitutes a means for adjusting the stroke length of the bearing 49, such stroke bein8 along a path parallel to the axis of rotation o the drive gear 30.
Although the invent:ion hcls been shown as embodied in a jigsaw, also known as a Sabre saw, it will be appreciated that tlle invention has applicabilit~J to other saws having reciprocating-type saw blades. For example, the present lnvention ma~J be employed in saws known in the art as ~eci.pro-cating or reciprocal saws.
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housing and arran~ed in the path of movement of the cross-head; resilient means urge the crosshead lnto engagement with this inclined surface for rocking the blade holder thereby to achieve orbital mo~ement. Other prior U. S. patents showing similar construction are ~nders No. 3,269,197 and Brucker No.
3,204,470. These mechanisms, although generally satisfactory, impose undue frictional restraints to the blade holder. More-over, these prior art mechanisms do not readily lend them-selves to providing a means to adjust or vary the orbital 0 path of movement of the reciprocating saw blades.
Summar Of The Invention In view of the foregoing, lt is an object of an aspect of my invention to provide a reciprocating saw where-in the pendular movement of the saw-blade is achieved by a direct coupling to the drive means which does not require an additional eccentric. It is an object of an aspect of my invention to provide an arrangement wherein the transverse motion is applied to the saw-blade holder at a location spaced away from the saw-blade where it can not be contami-nated by the chips cut by the saw-blade.
It is an object of an aspect of my invention to provide a reciprocating saw which requires no specially conigured saw b].ades to achieve pendular motion.
It is an object of an aspect of my invention to provide a reciprocating saw wherein the shape of the enclosed path traced by the saw-blade during pendular motion is inde-pendent of the position of the saw-blade holder. It is an ob~ect of an aspect of my invention to provide a recipro-cating saw wherein the enclosed path traced by the saw~blade can be made to have a pre-determined shape.
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Various aspects of the invention are as follows:
A power operated reciprocating saw or-jigsaw comprising: a housing; an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis;
bearing means for pivotally mounting said saw-blade holder in said housing; drive means for reciprocating the saw ~:~
blade holder in the direction of said longitudinal axis; and rotatable non-eccentric cam means operatively connected to said drive means for imparting a reciprocating movement to said saw-blade holder transverse to the reciprocating movement in said direction of said longitudinal axis where-by a saw-blade attached to said saw-blade holder will trace out an enclosed path of predetermined shape.
A power operated portable jigsaw comprising: a 15 housing; a saw-blade holder for holding a saw-blade; bearing :
means for pivotally mounting said holder in said housing;
drive means for reciprocating said saw-blade holder in a substantially vertical direction, and, a cam arrangement for imparting a pendular movement to said saw-blade ho:Lder;
the cam arrangement including: a body rotatably mounted in said housing and operatively connected to said drive ~ ~
means, said body defining an axis of rotation; said body -having a cam surace in surrounding relation to said axis of rotation, said cam surface belng ormed on said bod~
to have a predetermined contour indicative of the shape o~
the pendulax path traced by a blade attached to said blade holder; and, translation means for translating the rota-tional movement of said cam surface into a reciprocating movembnt of said saw-blade holder in a direction trans-:
verse to said vertical direction whereby a saw-blade attach~
ed to said saw-blade holder will trace out said pendular path.
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A power operated portable jigsaw comprising: a housing; an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis;
drive means for reciprocating said saw-blade holder in a substantially vertical direction; a first pivot bearing mounted in said housing for slide:ably holding said saw-blade holder at one portion thereof; a second pivot bearing or slideably holding said saw-blade holder at the remaining portion thereof; a cam arrangement for 10. acting on said second pivot bearing to reciprocate the same transversely to said vertical direction thereby imparting a pendular movement to said saw-blade holder; the cam arrangement including: a body rotatably mounted in said housing and operatively connected to said drive means, said body defining an axis of rotation; cam surface means formed on said body for rotation therewith; and, trans-lakion means for translatiny the rotational movement of said cam 3urface means into a reciprocating movement of said second pivot bearing over a predetermined stroke lèngth in a direction transverse to said vertical direction whereby a saw-blade at~ached.to said saw-blade holder will trace out an enclosed pendular path.
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The power operated portable jigsaw, embodying my invention and show~L for purposes of illustration, includes a housing and an elongated saw-blade holder for pivo~ally mounting the elongated saw-blade holder in the housing. Drive means are included for reciprocating the saw-blade holder in a substantiallY up and dow~L direction. It is a feature of my invention to provide rotatable non-eccentric cam means operatively connected to the drive means for im~arting a reciprocating movement to the saw-blade holder transverse to the reciprocating movement in the uP and down direction.
According to a feature of my invention, the cam arrangement for imparting the transverse movement to the elongated saw-blade holder includes a body rotatably mounted ~:in the housing and operatively connected to the drive means.
The body defines an axis of rotation. A cam surface is formed on said body in surrounding relation to the axis of rotation.
The cam surface is formed to have a pre-determined contour in.dicative of the shape of pendular pa~h traced by a blade : attached to the blade holder.
Translation means translate the rotational move-ment of the cam surface into a reciprocating movement of the saw-blade holder in a dlrection transverse to the vertical direction whereby a saw-blade attached to the saw-hlade holder trace out the enclosed pendular path.
The translation meatL,s can lnclude a bearing slide-ably holding the saw-blade holder and mounted on the housing so as to be reciprocably movable over a predetermined stroke ::
, length in a direction transverse to said saw-blade holder. A
resilient member urges thebearinglnto engagement with the cam surface means whereby the bearing rides on the cam surface me-ans and reciprocally moves through its pre-determined strol~e len~th in response to Ihe ro~ational movemen~ of the cam sur-face.
By providing the above described cam arrangement, the reciprocal saw according to my invention achieves the advantage that a minimal number of parts are needed to provide the motion in the transverse direction and this eliminates the need for an additional eccenlric. The cam arrangement provides a cam surface where ~he ~osition of the cam surface with respect to the lo~er bearing of the saw-blade holder is continuously changing so that the carrier which is pressed against the cam surface moves in the horizontal direction and this provides the desired reciprocal movement in the trans-verse direction. In this way, the desired path traced by a point on the saw-blade can be changed by configuring the form of the cam surface as desired. By forming the rotating cam surface means on a body rotatably mounted in the housing of the jigsaw, the need for an additional eccentric mechanism and guide arrangement becomes unncessary.
In tL~e instant inventionj the lower bearing is slldeably mounted in the housing so as to enable the cam surface formed on the hub-l.ike member to coact therewith and be brought to bear thereagainst under the action o a resilient member such as a spring. In this ~ay, it is possible to' adjust 3~
the end position of the lower bearing, for example, with the aid of an eccentric shaft to thereby vary the stroke length.
The eccentric shaft achieves a continuous adjustment of the range of the stroke length of the transverse movement between a maximum and zero by shifting the end position of the lower bearing in the region of the cam surface of the hub member which acts on this bearing.
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Brief DescriPtion Of The Drawin~,s Figure 1 is a side view, partially in elevation and -partially in section, showing a jigsaw embodying the present invention;
Fi~ure 2 is a s~ction taken along the line 2-2 of Figure l;
Figure 2A is a section taken along the line 2A-2A
of ~igure 2 ~with the drive gear rotated 90 from the position shown in Figure l);
: Figures 3A, 3B and 3C illustrate several of the possible paths of movement of a jigsaw blade attached to a saw embodyin~ the present invention;
Figure 4 is an ~nlarged fron~ view of the drive gear including the annular concen-tric cam surface;
Figure 5 is a section taken along the line 5-5 of Figure 4;
Figure 6 is an enlarged, fragmentary sectional view primarily illustrating the means for varying the enclosed p~th of movement of the jigsaw blade;
Figure 7 is an enlargedl fragmentary side elevational view show:Lng a manually o~erated member for varying the enclosed path of orbital movement of the jigsaw blade;
Figure 8 is a section ~aken along the lin.e 8-8 of Figure 7; ' . -8-~.26~L3~
Figure 9 is an enlarged, fragmentary, front ele~ational view showing a modified construction for preventing rotation of the blade holder;
Figure 10 is a section taken along the line lO-10 of Figure 9;
Figure 11 is an enlarged, fragmen~ar7 view, partially in section, showing an alternate form of resilient means associated with the blade holder; and Figure 12 ls an enlarged sectional view showing an alternate form of the lower bearing assembly which is engaged by the concentric cam on the drive gear.
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~escription Of The Preferred Embodiments Of The Invention -Referring primarily to Figure 1, the present inven-tion is shown as embodied in a portable, electrically powered Jlgsaw, generally designated 10. The jigsaw includes a housing 11 having an opening 12 de~ining a handle portion 14.
A leg 15 is connected to the underside of the housing 11; the leg su~ports a shoe 16 of conventional construction. '~he shoe includes a bifurcated portion 17 receiving a jigsaw blade 18.
The housing ll mounts an electric motor 20 including ~an armature shaft 21, the latter having,at its outer end,a formation of gear teeth 22. The armature shaft 21 is rotatably received within a sleeve bearing 24. This sleeve bearing is mounted in an openin~ 25 formed in clam-shaped type gear case members 26 and 27.
The teeth 22 on the outer end of the armature shaft 21 are in meshing engagemen~ with an annular formation of eeeth 28 formed on a drive gear 30. m e drive gear includes a concentric opening 3I receiving a shaft 32. This shaft is rotatably received in a sleeve bearing 33, the latter being mounted in a bore 34 for~ed in the gear case members 26 and 27.
The drive gear 30 includes an eccentrlcall~ formed bore 3G mounting a pin 37. This pin mounts a roller 38 received within a channel 39 which is mounted in a notch for~ed in a blade holder 40. Thus, it is apparent that the roller 38, supported on the eccentrically mounted pin 37, cooperates with the channel 39 to form a Scotch-yoke ~ 3 mechanism for imparting reciprocal movement of the blade holder 40 along its longitudinal axis upon rotation of the drive gear 30.
The eccentrically mounted pin 37 and roller 38 would tend to create an lmbalanced situation for the drive gear 30.
However, such a situation is avoided by providing a suitable bore or recess (not shown) in the drive gear to act as a counterbalancing means.
The upper portion of the blade holder 40, which is circular in sross-section, is slideably received within the ` ; ~bore~41 of a spherical bearing member 42. This bearing member is swivelly mounted within recesses 43 and 44 formed in the gear~case members 26, 27 and another recess 45 formed in a ~front gear case member 46.~ Thus, it is apparent that the ~upper bearing 42 mounts the blade holder for both reciprocatlng movement and pivoting movement; this pivoting movement occurs about the axis 47.
~ The lower portion of the blade holder 40, also circular in cross-section, is slideably received within a bore 48 formed in a bearing member 49. This bearing member is suitably mounted in various guideways constituted by the walls of rece.sses Sl and 52 :~ormed in the gear case members 26 ancl 27, and by further guideways formed in a recess si in the Eront gear case 46, such that the bearing ~lember 49 may move in a reciprocal path ~rom left to right as shown in Flgure 1. That is to say, the lower bearing member 49 ~s mounted for reciprocal movement along a path which i8 trans-verse to the reciprocal path of movement of the blade holder ~; which results from rotation of the drive gear 30 through the agency of the Scotch-yoke mechanism.
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The amount of reciprocal rnovement of the bearlng 49 is quite small; in-this regard, a wall surface 54 in the recess 53 limits movement of the bearing in the fo~ard direction, i.e., to the left as viewed in Figure 1. The diameter of the bore 48 is sufficiently dimensioned, with respect to ~he diame~er of the blade holder 4~, such that the bearing 49 may reciprocate and impart corresponding reciprocal movement to the lower portion of the blade holder without binding against the latter. Therefore, the bearing 49 suppor~s the lower portion of the blade holder for both reciprocal movement and pivotal mo~ement; this pivotal move-ment occurs about an imaginary axis 55.
-~ Referring now primarily to Figures 4 and 5J the drive gear 30 has a concentric, annular surface defining a cam face 57. This cam surface is, ln the embodiment shown for purposes of illustration, planar and contained in a plane which is slightly inclined with respect to the axis of rotatLon of the drive gear. The high and low points o:f the cam, 57a and 57b, respecti~rely, are illustrated in Figure 5.
The phase angle ~ (see Figure 4) may be defined as the angle, measured in the direction of rotation of the drive ~ear, from the high points 57a of the cam to a radius containing the eccentricaLly mounted pin 37.
In the embodiment of the cam shown for purposes of i].lustrati.on, the cam is s~mmetr-lcal and the high and low points 57a and 57b are diametri.caLly opposed. It will be understood that it is within the scope of the present inven-tion to provide other non-symmetrical cam surfaces. In this regard, the particular shape of the cam surface is a matter .
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of choice to ob~ain the desired path of movement of the saw blade, all as will-become apparent from the following speci-fication.
The lower bearing 49 includes a cam follower surface 60 arranged for engagement with the cam face 57. A leaf spring ~l, suitably mounted from the gear case 46, engages the channel 39 on the blade holder 40 for urging the cam fol~ower face 60 into engagement with the annular cam face 57. When the cam face 57 is in engagemen~ with the cam follower surface 60 it will be apparent that the lower bearing member 49 ~ill reciprocate back and forth (left to right as seen in Figure 1) in response to rotation of the drive gear 30. As will be explained more fully below, such reciprocating movement of the lower bearing 49 will cause the saw blade 18 to ~race out the enclosed orbital path of movement shown in solid lines in Figures 3A, 3B and 3C.
The present invention includes means for varyi.ng or adjusting reciprocal movement of the lower bearing 49 for in turn varying the shape o the path of movement of the saw blade. To this end, the gear case members 26 and 27 rotatably mount a pin 64. This pin carries an eccentrically mo~mted cam surface 65 (Figure 6) arranged for enga~ement with a cam follower surEace 66 on the lower bearin~ 4~.
When ~he pin 64 is rotated for positioning the cam 65 in the position shown in Flgure 1, this carn will not be permitted to engage the cam iollower surface 66 on the bearing 49; thus, when the pin 64 is so positioned, full reciprocal rnovement of the bearing 49 will be permitted in which event .
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the saw blade will trace out the enclosed path of movement shown in solid lines in Figure 3C. If the pin 64 i~ rotated for positioning the cam 65 in the position shown in Figure 6, t~e la~ter will engage the cam ~ollower face 66 for holding the cam Eollower 60 out of e~gagement with the annular cam surface 57; when the cam 65 is in the position just described, the lo~er bearing 49 will not be permitted to reciprocate and the saw blade will simply reciprocate along a rectilinear path as shown by the broken line in Figure 3A. If the pin 64 is rotated for orienting the cam 65 between the two positions shown in Figures 1 and 6, the bearing member 49 will be reciprocated intermittently through a stroke, less than its full stroke, for modifying the enclosed path of movement of the saw blade through a variety of paths depending on the orientation of the cam 65. One such modified path of movement, to be rererred to in greater detail below, is shown in Figure In the embodiment of the invention shown for pur-poses of illustration, mears are provided for orienting the cam 65 in four dif~erent positions. In this regard, and now referring particularly to Figures 7 and 8, a lever 68 is secured to the pin 63 exteriorly of the housing 11. The lever 68, adapted to be manuall~ operated, includes a finger portion 63a in which a blind bore 69 is formed. A detent ball 70 is received in this bore and urged outward].y thereof by a coil spring 71. The detent ball. is adapted to be received in a plurality of recesses 72 formed in the hou;si.ng 11 for releasably holding the lever 68 in any one of its four positions.
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Assume the manuall~J operated lever 68 is positioned for permitting full reciprocating movement of the bearing 49.
With the lever 68 so positioned, the movement of the blade will be as depicted in Figure 3C. The blade 18 is shown in its fo~ardmost position in solid lines; the rearwardmost position of the blade is shown by broken lines. Considering a single tooth l~a, the -~ip of that tooth will occupy the Point A when the lower bearing is in its fo~ardmost position, i.e., when the cam ~ollower surface 60 is being engaged by -the cam 57 at its highes~ point 57a. As the blade moves upwardly, the same will retreat until the tip of the tooth 18a reaches the Point B, which is the most retracted (upper) position of ~the blade. The blade now changes its direction of movement resulting from the S~cotch-yoke mechanism and begins to descend, retreating until the tip of the tooth 18a reaches the Point C;
thls lS the~most re~reated position of the blade which occurs ~- when the cam point 57b is engaging the cam follower surface 60. As the drive gear continues to rotate, the blade continues to descend and at the same time begins to advance forwardly mtil the tip of the tooth 18a reaches the Point D. At this point, the blade changes directlon as a result of operation of the Scotch-yoke mechanism and begins to retract upwardly at the same time moving forwardly as a result of the annular cam 57.
The upward path oE movement ~rom Poin~ D to Point ~ represents the portion of the stroke used Eor cutting.
As mentioned above, the orbit adjusting cam 65 may be positioned to hold the cam follower surface 60 Otlt of engagement with the annular cam surface 57 at all times. In this mode of operation, the saw bl.ade~will simply reclprocate ~ ~ 2 ~ 3 ~
in a rectilinear path as indicated by the broken line in Figure 3A.
As also mentioned above, it is possible to orient the orbit adjus,ment cam 65 in one or more intermPdiate positions thereby to modify ~he orbltal pa~h of movement of the saw blade. ~ :
Figure 3B illustrates such modi~ied orbital movement occurring when the lever 6~ is located i~ onP of its intermediate positions. In this partial orbi.t set~ing, the cam follower : surface 63 will be engaged by the annular cam surface 57 from Point A to Point B. Thereafter, the adjustment cam 65 will prevent the cam surface 60 from following the cam 57, and consequently the blade path is rectilinear as indicated by the :broken line from Point B to Point C in Figure 3B. The blade ~; ~ will then change its direction of movement as a consequence :of the Scotch-yoke mechanism and will re-tract upwardly to : Point A. At this last mentioned point, the cam surface 57 will again engage the cam follower surface 60 such that the tip of the tooth 18a will follow the solid line position ~rom Point A uPwardly and then downwardly to Point B as shown in Figure 3B.
: In some instances, it may be desirable to use a lighter spring than the return spring 61 shown in the Figure 1 embodiment. Such a llghter spring may not be ade~uate to prevent rotation oE the blade holder 40. However, rotation o the bl.ade holder may be prevented by the alternflte con-struction shown in Figures 9 and 10. There, the blade hvlder 40' includes a longitudinally extending slot 75. The lower bearing member 49' carries a pin 76 which is slldeably ~ -16-~2G~34 received within the slot 75 thereby to prevent rotation of the blade holder 40'.
Figure 11 illustrates an alternate form of return spring which may be employed with the modiied construction shown in Figures 9 and 10. In the Figure 11 modification, the gear case 46' is provided with a recess 78, the walls of which constitute a guideway for the bearing member 49'. The recess 78 also receives a light coil spring 80; this sprlng engages the bearing 49' and acts to urge the latter agalns~
the cam surfaces 57, 65.
It may also be desirable to provide the lower bearing 49 with a cam roller for engagement with the annular cam surface 57. Such an alternate construction is shown in Figure 12 ~here the lower bearing member 49" is provided with a bore 82 which receives a pin 83. A roller 84, received within a cavity 86 formed in the bearing 49", is ro-tatably unted on the pin 83. The roller 84 rides on the cam surface 57 as permitted depending on the orientation of the adjustment cam 65.
In sum, the present invention includes an elongated saw blade holder 40, which holder defines a longitudinal axis.
The drive gear 30, along with the eccentrically mounted roller 38 and channel 39, constitute a Scotch-yoke mechanism for reciprocating the saw blade holder .in the di.rection of such longit:udi.nal axis. The 9aw blade holder 40 is pivotally mounted in the housing by the spherical bearing member 42 , f~ 2~3~
and by the bearing 49 (as a result of the clearance between the dia~eter of the bore 48 and the diamter of the blade holder 40). The annular cam sur~ace 57 constitutes a rotatable non-eccentric cam associated with the drive means and imparts a reciproca~ing movement to the saw blade holder transversely to the reciproca~ing movement of the holder along the latter's longitudinal axis whereby a saw blade attached to the blade holder will trace out an enclosed path of pre-determined shape.
The cam follower face 60 or roller 84, as the case may be, constitutes translation means 'or translating rotational movement of the cam surface 57 into reciprocating movement of the saw blade holder in a direction transverse to the vertical longitudinal movement of the saw blade holder.
It should also be noted that the lower bearing 49 acts as a carrier in that it slideably supports the blade holder and is also mounted in the gear case members 26, 27 and 46 so as to be reciprocally moveable over a pre-determined stroke in a direction transverse to the longitudinal movemen~ of the saw blade holder. Of course, the cam 65 constitutes a means for adjusting the stroke length of the bearing 49, such stroke bein8 along a path parallel to the axis of rotation o the drive gear 30.
Although the invent:ion hcls been shown as embodied in a jigsaw, also known as a Sabre saw, it will be appreciated that tlle invention has applicabilit~J to other saws having reciprocating-type saw blades. For example, the present lnvention ma~J be employed in saws known in the art as ~eci.pro-cating or reciprocal saws.
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Claims (38)
1. A power operated jigsaw comprising:
a housing;
an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis;
bearing means for pivotally mounting said saw-blade holder in said housing;
drive means for reciprocating the saw-blade holder in the direction of said longitudinal axis; and rotatable non-eccentric cam means operatively con-nected to said drive means for imparting a reciprocating movement to said saw-blade holder transverse to the reciprocating movement in said direction of said longitudinal axis whereby a saw-blade attached to said saw-blade holder will trace out an enclosed path of predetermined shape.
a housing;
an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis;
bearing means for pivotally mounting said saw-blade holder in said housing;
drive means for reciprocating the saw-blade holder in the direction of said longitudinal axis; and rotatable non-eccentric cam means operatively con-nected to said drive means for imparting a reciprocating movement to said saw-blade holder transverse to the reciprocating movement in said direction of said longitudinal axis whereby a saw-blade attached to said saw-blade holder will trace out an enclosed path of predetermined shape.
2. The power operated Jigsaw of Claim 1 wherein said rotatable non-eccentric cam means comprises:
a body rotatably mounted in said housing and oper-atively connected to said drive means; said body defining an axis of rotation;
cam surface means formed on said body for rotation therewith; and translation means for translating the rotational movement of said cam surface means into a reciprocating movement of saw saw-blade holder in a direction transverse to said vertical direction whereby a saw-blade attached to said saw-blade holder will trace out said enclosed path.
a body rotatably mounted in said housing and oper-atively connected to said drive means; said body defining an axis of rotation;
cam surface means formed on said body for rotation therewith; and translation means for translating the rotational movement of said cam surface means into a reciprocating movement of saw saw-blade holder in a direction transverse to said vertical direction whereby a saw-blade attached to said saw-blade holder will trace out said enclosed path.
3. The power operated jigsaw of Claim 2, said translation means including:
a carrier slideably holding said elongated saw-blade holder and mounted on said housing so as to be reciprocally movable over a predetermined stroke length in a direction transverse to said saw-blade holder; and resilient means for urging said carrier into engagement with said cam surface means whereby said carrier rides on said cam surface means and reciprocally moves through said predetermined stroke length in response to the rotational movement of said cam surface means.
a carrier slideably holding said elongated saw-blade holder and mounted on said housing so as to be reciprocally movable over a predetermined stroke length in a direction transverse to said saw-blade holder; and resilient means for urging said carrier into engagement with said cam surface means whereby said carrier rides on said cam surface means and reciprocally moves through said predetermined stroke length in response to the rotational movement of said cam surface means.
4. The power operated jigsaw of Claim 3, said bearing means comprising:
a first pivot bearing mounted in said housing for slideably holding said saw-blade holder at one portion thereof; and a second pivot bearing mounted on said carrier for slideably holding said saw-blade holder at the remaining portion thereof.
a first pivot bearing mounted in said housing for slideably holding said saw-blade holder at one portion thereof; and a second pivot bearing mounted on said carrier for slideably holding said saw-blade holder at the remaining portion thereof.
5. The power operated jigsaw of Claim 3 wherein said cam surface means comprises an annular face cam con-centric with said rotation axis.
6. The power operated jigsaw of Claim 5 wherein said body is mounted in said housing with said rotation axis being substantially parallel to the stroke of said carrier, said cam surface being contoured at each point along its arcuate length to have a predetermined elevation to the direction of said stroke of said carrier to thereby recipro-cate said carrier through said stroke length in response to the rotation of said body about said rotational axis thereof, the slope of said cam surface being selected to cause said carrier to be reciprocated in such a manner that the tip of a blade connected to said saw-blade holder traces out an enclosed path of predetermined shape as said saw-blade holder is reciprocated by said drive means whereby optimum cutting characteristics are obtained.
7. The power operated jigsaw of Claim 6 comprising:
roller means at the interface of said carrier and said annular cam surface for minimizing friction therebetween.
roller means at the interface of said carrier and said annular cam surface for minimizing friction therebetween.
8. The power operated jigsaw of Claim 3 comprising:
means for adjusting said stroke length of said carrier.
means for adjusting said stroke length of said carrier.
9. The power operated jigsaw of Claim 8 wherein said adjusting means comprises: a cam eccentrically mounted on said housing so as to be rotatable in-to the path of said carrier so as to vary the magnitude of said stroke length through a range extending from said predetermined stroke length to zero stroke length.
10. The power operated jigsaw of Claim 2 wherein said drive means comprises: eccentric means formed on said body and said saw-blade holder for reciprocating said saw-blade holder in the direction of said longitudinal axis.
11. A power operated portable jigsaw comprising:
a housing;
a saw-blade holder for holding a saw-blade;
bearing Means for pivotally mounting said holder in said housing;
drive means for reciprocating said saw-blade holder in a substantially vertical direction; and, a cam arrangement for imparting a pendular movement to said saw-blade holder; the cam arrangement including:
a body rotatably mounted in said housing and opera-tively connected to said drive means, said body defining an axis of rotation;
said body having a cam surface in surrounding rela-tion to said axis of rotation, said cam surface being formed on said body to have a predetermined contour indicative of the shape of the pendular path traced by a blade attached to said blade holder; and, translation means for translating the rotational movement of said cam surface into a reciprocating movement of said saw-blade holder in a direction transverse to said vertical direction whereby a saw-blade attached to said saw-blade holder will trace out said pendular path.
a housing;
a saw-blade holder for holding a saw-blade;
bearing Means for pivotally mounting said holder in said housing;
drive means for reciprocating said saw-blade holder in a substantially vertical direction; and, a cam arrangement for imparting a pendular movement to said saw-blade holder; the cam arrangement including:
a body rotatably mounted in said housing and opera-tively connected to said drive means, said body defining an axis of rotation;
said body having a cam surface in surrounding rela-tion to said axis of rotation, said cam surface being formed on said body to have a predetermined contour indicative of the shape of the pendular path traced by a blade attached to said blade holder; and, translation means for translating the rotational movement of said cam surface into a reciprocating movement of said saw-blade holder in a direction transverse to said vertical direction whereby a saw-blade attached to said saw-blade holder will trace out said pendular path.
12. The power operated portable jigsaw of Claim 11 wherein said drive means comprises eccentric means formed on said body and said saw-blade holder for reciprocating said saw-blade holder is said vertical direction.
13. A power operated portable jigsaw comprising:
a housing;
an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis;
drive means for reciprocating said saw-blade holder in a substantially vertical direction;
a first pivot bearing mounted in said housing for slideably holding said saw-blade holder at one portion thereof;
a second pivot bearing for slideably holding said saw-blade holder at the remaining portion thereof;
a cam arrangement for acting on said second pivot bearing to reciprocate the same transversely to said vertical direction thereby imparting a pendular movement to said saw-blade holder; the cam arrangement including:
a body rotatably mounted in said housing and opera-tively connected to said drive means, said body defining an axis of rotation;
cam surface means formed on said body for rotation therewith; and, translation means for translating the rotational movement of said cam surface means into a reciprocating move-ment of said second pivot bearing over a predetermined stroke length in a direction transverse to said vertical direction whereby a saw blade attached to said saw-blade holder will trace out an enclosed pendular path.
a housing;
an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis;
drive means for reciprocating said saw-blade holder in a substantially vertical direction;
a first pivot bearing mounted in said housing for slideably holding said saw-blade holder at one portion thereof;
a second pivot bearing for slideably holding said saw-blade holder at the remaining portion thereof;
a cam arrangement for acting on said second pivot bearing to reciprocate the same transversely to said vertical direction thereby imparting a pendular movement to said saw-blade holder; the cam arrangement including:
a body rotatably mounted in said housing and opera-tively connected to said drive means, said body defining an axis of rotation;
cam surface means formed on said body for rotation therewith; and, translation means for translating the rotational movement of said cam surface means into a reciprocating move-ment of said second pivot bearing over a predetermined stroke length in a direction transverse to said vertical direction whereby a saw blade attached to said saw-blade holder will trace out an enclosed pendular path.
14. The power operated portable jigsaw of Claim 13, said translation means including:
a carrier holding said second pivot bearing, said carrier being mounted in said housing so as to be reciprocally movable over said pre-determined stroke length in said direction transverse to said vertical direction; and resilient means for urging said carrier into engage-ment with said cam surface means whereby said carrier rides on said cam surface means and reciprocally moves through said pre-determined stroke length in response to the rotational movement of said cam surface means.
a carrier holding said second pivot bearing, said carrier being mounted in said housing so as to be reciprocally movable over said pre-determined stroke length in said direction transverse to said vertical direction; and resilient means for urging said carrier into engage-ment with said cam surface means whereby said carrier rides on said cam surface means and reciprocally moves through said pre-determined stroke length in response to the rotational movement of said cam surface means.
15. The power operated portable jigsaw of Claim 14 wherein said cam surface means comprises an annular face cam concentric with said rotation axis.
16. The power operated portable jigsaw of Claim 15 wherein said body is mounted in said housing with said rotation axis being substantially parallel to the stroke of said carrier, said cam surface being contoured at each point along its arcuate length to have a pre-determined elevation in the direction of said stroke of said carrier to thereby reciprocate said carrier through said stroke length in response to the rotation of said body about said rotational axis thereof, the slope of said cam surface being selected to cause said carrier to be reciprocated in such a manner that the tip of a blade connected to said saw-blade holder traces out an enclosed path of pre-determined shape as said saw-blade holder is reciprocated by said drive means whereby optimum cutting characteristics are obtained.
17. The power operated portable jigsaw of Claim 14 comprising means for adjusting said stroke length of said carrier.
18. The power operated portable jigsaw of Claim 17 wherein said adjusting means comprises: a cam eccentrically mounted on said housing so as to be rotatable into the path of said carrier so as to vary the magnitude of said stroke length through a range extending from said pre-determined stroke length to zero stroke length.
19. The power operated portable jigsaw of Claim 13 wherein said drive means comprises: eccentric means formed on said body and said saw-blade holder for reciprocating said saw-blade holder in the direction of said longitudinal axis.
20. A power operated reciprocating saw comprising:
a housing;
an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis;
bearing means for pivotally mounting said saw-blade holder in said housing;
drive means for reciprocating the saw-blade holder in the direction of said longitudinal axis; and rotatable non-eccentric cam means operatively connected to said drive means for imparting a reciprocating movement to said saw-blade holder transverse to the reciprocating movement in said direction of said longitudinal axis whereby a saw-blade attached to said saw-blade holder will trace out an enclosed path of pre-determined shape.
a housing;
an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis;
bearing means for pivotally mounting said saw-blade holder in said housing;
drive means for reciprocating the saw-blade holder in the direction of said longitudinal axis; and rotatable non-eccentric cam means operatively connected to said drive means for imparting a reciprocating movement to said saw-blade holder transverse to the reciprocating movement in said direction of said longitudinal axis whereby a saw-blade attached to said saw-blade holder will trace out an enclosed path of pre-determined shape.
21. The power operated reciprocating saw of Claim 20 wherein said rotatable non-eccentric cam means comprises:
a body rotatably mounted in said housing and operatively connected to said drive means; said body defining an axis of rotation;
cam surface means formed on said body for rotation therewith; and translation means for translating the rotational movement of said cam surface means into a reciprocating movement of said saw-blade holder in a direction transverse to said vertical direction whereby a saw-blade attached to said saw-blade holder will trace out said enclosed path.
a body rotatably mounted in said housing and operatively connected to said drive means; said body defining an axis of rotation;
cam surface means formed on said body for rotation therewith; and translation means for translating the rotational movement of said cam surface means into a reciprocating movement of said saw-blade holder in a direction transverse to said vertical direction whereby a saw-blade attached to said saw-blade holder will trace out said enclosed path.
22. The power operated reciprocating saw of Claim 21, said translation means including:
a carrier slideably holding said elongated saw-blade holder and mounted on said housing so as to be reciprocally movable over a pre-determined stroke length in a direction transverse to said saw-blade holder; and resilient means for urging said carrier into engagement with said cam surface means whereby said carrier rides on said cam surface means and reciprocally moves through said pre-determined stroke length in response to the rotational movement of said cam surface means.
a carrier slideably holding said elongated saw-blade holder and mounted on said housing so as to be reciprocally movable over a pre-determined stroke length in a direction transverse to said saw-blade holder; and resilient means for urging said carrier into engagement with said cam surface means whereby said carrier rides on said cam surface means and reciprocally moves through said pre-determined stroke length in response to the rotational movement of said cam surface means.
23. The power operated reciprocating saw of Claim 22, said bearing means comprising:
a first pivot bearing mounted in said housing for slideably holding said saw-blade holder at one portion thereof; and a second pivot bearing mounted on said carrier for slideably holding said saw-blade holder at the remaining portion thereof.
a first pivot bearing mounted in said housing for slideably holding said saw-blade holder at one portion thereof; and a second pivot bearing mounted on said carrier for slideably holding said saw-blade holder at the remaining portion thereof.
24. The power operated reciprocating saw of Claim 22 wherein said cam surface means comprises an annular face cam concentric with said rotation axis.
25. The power operated reciprocating saw of Claim 24 wherein said body is mounted in said housing with said rotation axis being substantially parallel to the stroke of said carrier, said cam surface being contoured at each point along its arcuate length to have a pre-determined elevation to the direction of said stroke of said carrier to thereby reciprocate said carrier through said stroke length in response to the rotation of said body about said rotational axis thereof. the slope of said cam surface being selected to cause said carrier to be reciprocated in such a manner that the tip of a blade connected to said saw-blade holder traces out an enclosed path of pre-determined shape as said saw-blade holder is reciprocated by said drive means whereby optimum cutting characteristics are obtained.
26. The power operated reciprocating saw of Claim 25 comprising: roller means at the interface of said carrier and said annular cam surface for minimizing friction there-between
27. The power operated reciprocating saw of Claim 22 comprising:
means for adjusting said stroke length of said carrier.
means for adjusting said stroke length of said carrier.
28. The power operated reciprocating saw of Claim 27 wherein said adjusting means comprises: a cam eccentrically mounted on said housing so as to be rotatable into the path of said carrier so as to vary the magnitude of said stroke length through a range extending from said pre-determined stroke length to zero stroke length.
29. The power operated reciprocating saw of Claim 21 wherein said drive means comprises: eccentric means formed on said body and said saw-blade holder for reciproca-ting said saw-blade holder in the direction of said longitudi-nal axis.
30. A power operated jig saw comprising: a housing;
an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis; bearing means for pivotally mounting said saw-blade holder in said housing; drive means for reciprocating the saw-blade holder in the direction of said longitudinal axis to provide a down-ward stroke and an upward working stroke; and, rotatable non-eccentric cam means operatively connected to said drive means for imparting a reciprocating movement to said saw-blade holder transverse to the reciprocating movement in said direction of said-longitudinal axis with said cam means having a configuration such that a saw-blade attached to said saw blade holder will, in operation, trace out an enclosed path of predetermined shape such that the saw blade will be made to advance into a workpiece over substantially the entire upward working stroke.
an elongated saw-blade holder for holding a saw-blade, the saw-blade holder defining a longitudinal axis; bearing means for pivotally mounting said saw-blade holder in said housing; drive means for reciprocating the saw-blade holder in the direction of said longitudinal axis to provide a down-ward stroke and an upward working stroke; and, rotatable non-eccentric cam means operatively connected to said drive means for imparting a reciprocating movement to said saw-blade holder transverse to the reciprocating movement in said direction of said-longitudinal axis with said cam means having a configuration such that a saw-blade attached to said saw blade holder will, in operation, trace out an enclosed path of predetermined shape such that the saw blade will be made to advance into a workpiece over substantially the entire upward working stroke.
31. The power operated jig saw of claim 30 wherein said rotatable non-eccentric cam means comprises: a body rotatably mounted in said housing and operatively connected to said drive means; said body defining an axis of rotation;
cam surface means formed on said body for rotation therewith;
and, translation means for translating the rotational move-ment of said cam surface means into the reciprocating move-ment of said saw-blade holder in said direction transverse to said vertical direction whereby a saw-blade attached to said saw-blade holder will trace out said enclosed path.
cam surface means formed on said body for rotation therewith;
and, translation means for translating the rotational move-ment of said cam surface means into the reciprocating move-ment of said saw-blade holder in said direction transverse to said vertical direction whereby a saw-blade attached to said saw-blade holder will trace out said enclosed path.
32. The power operated jig saw of claim 31, said translation means including: a carrier slideably holding said elongated saw-blade holder and mounted on said housing so as to be reciprocally movable over a predetermined stroke length in a direction transverse to said saw-blade hoder;
and, resilient means for urging said carrier into engagement with said cam surface means whereby said carrier rides on said cam surface means and reciprocally moves through said predetermined stroke length in response to the rotational movement of said cam surface means.
and, resilient means for urging said carrier into engagement with said cam surface means whereby said carrier rides on said cam surface means and reciprocally moves through said predetermined stroke length in response to the rotational movement of said cam surface means.
33. The power operated jig saw of claim 32, wherein said cam surface means comprises an annular face cam concentric with said rotation axis.
34. The power operated jig saw of claim 33, wherein said body is mounted in said housing with said rota-tion axis being substantially parallel to the stroke of said carrier, said cam surface being contoured at each point along its arcuate length to have a predetermined elevation in the direction of said stroke of said carrier to thereby reciprocate said carrier through said stroke length in response to the rotation of said body about said rotational axis thereof, the slope of said cam surface being selected to cause said carrier to be reciprocated in such a manner that the tip of a blade connected to said saw-blade holder traces out said enclosed path of predetermined shape as said saw-blade holder is reciprocated by said drive means whereby optimum cutting characteristics are obtained.
35. The power operated jig saw of claim 34 com-prising: roller means at the interface of said carrier and said annular cam surface for minimizing friction there-between.
36. The power operated jig saw of claim 32 comprising: means for adjusting said stroke length of said carrier.
37. The power operated jig saw of claim 36 wherein said adjusting means comprises: a cam eccentrically mounted on said housing so as to be rotatable into the path of said carrier so as to vary the magnitude of said stroke length through a range extending from said predetermined stroke length to zero stroke length.
38. The power operated jig saw of claim 31 wherein said drive means comprises: eccentric means formed on said body and said saw-blade holder for reciprocating said saw-blade holder in the direction of said longitudinal axis.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US4354579A | 1979-05-29 | 1979-05-29 | |
| US043,545 | 1979-05-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1126134A true CA1126134A (en) | 1982-06-22 |
Family
ID=21927704
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA340,120A Expired CA1126134A (en) | 1979-05-29 | 1979-11-19 | Cam mechanism for imparting orbital movement to the blade of a reciprocating saw |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1126134A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110403673A (en) * | 2013-10-28 | 2019-11-05 | 物理科学公司 | Method and apparatus for soft tissue anatomical |
-
1979
- 1979-11-19 CA CA340,120A patent/CA1126134A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110403673A (en) * | 2013-10-28 | 2019-11-05 | 物理科学公司 | Method and apparatus for soft tissue anatomical |
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| MKEX | Expiry |