US 3678934 A
A handpiece has an elongated tubular housing which is connectable at one end either to an air motor or to a sheath for a motor driven cable and which is adapted for supporting a tool, such as an osteotome or a saw blade at the other end thereof. Between these two are located an input drive mechanism, a crank mechanism and an output driven mechanism whereby the rotational force of the motor or cable is converted into a reciprocation for driving the osteotome or the saw.
Description (OCR text may contain errors)
United States Patent Warfield et al.
[ 51 July 25, 1972 POWER OSTEOTOME  Inventors: Wayne N. Warfield; Russell K. Eaton, both of Kalamazoo Township, Kalamazoo County, Mich.
 Assignee: Stryker Corporation, Kalamazoo, Mich.
 Filed: Aug. 13, 1970  Appl. No.: 63,460
75/104, 74/606, 128/310  Int. Cl ..A6lb 17/14,A6lb 17/16,F16h 57/02  Field of Search ..74/25, 44, 104, 606; 128/310, 128/3 l 7  References Cited UNITED STATES PATENTS 2,372,731 4/1945 Nalbach et al ..74/44 2,555,809 6/1951 Naab ..74/44 X 2,702,550 2/1955 Rowe.. .....l28/3l7 2,905,168 9/1959 Henry.... .....74/44 X 3,007,230 11/1961 Riedl ..74/44 X 3,554,197 l/l971 Dobbie ..128/317 Primary Examiner-Channing L. Pace AttorneyWoodhams, Blanchard and Flynn [571 I ABSTRACT A handpiece has an elongated tubular housing which is connectable at one end either to an air motor or to a sheath for a motor driven cable and which is adapted for supporting a tool, such as an osteotome or a saw blade at the other end thereof. Between these two are located an input drive mechanism, a crank mechanism and an output driven mechanism whereby the rotational force of the motor or cable is converted into a reciprocation for driving the osteotome or the saw.
8 Claims, 7 Drawing Figures Patented July 25, 1972 4 Sheets-Sheet 1 Patented July 25, 1972 3,678,934
4 Sheets-Sheet 2 Patented July 25, 1972 4 Sheets-Sheet 5 WWE V MAM w w M Mr. 4 WW 0 1 PM v Patented July 25, 1972 4 Sheets-Sheet 4 Wm m MM 0 1? K m aw A WWW wm POWER OSTEOTOME This invention relates in general to a power-driven handpiece for operating a tool and, more particularly, to a handpiece adapted for connection to an air motor or cable drive and capable of actuating a tool bit or instrument of the type used in surgery.
It has been known for many years to use power-operated instruments to perform surgical operations, particularly in bone surgery. Initially, the source of energy was primarily an electric motor connected either directly, or remotely through a cable, to a handpiece upon which the tool or instrument was mounted. Later on, air motors were, and still are, extensively used because, among other things, they could be readily adapted to operate at extremely high speeds and still be relatively small in size. That is, the air motors could be easily integrated into the handpiece which supported the tool or instrument. I
The subsequent disclosure will be directed to, and will use terminology characteristic of, the medical profession because this is the background from which the invention has developed. However, it will be recognized by persons acquainted with power-operated hand tools that the invention is equallyadaptable for use in fields other than medicine, such as woodworking.
I-Ieretofore, medical handpieces have been especially constructed and adapted for a single type of performance or for use with a particular type of instrument. That is, they were either designed to operate'a power driven saw, or a power driven drill, or a power driven osteotome and, in most instances, none of the parts of one such handpiece were readily interchangeable with the parts of another handpiece.
It is well known and well established that power operated devices used by surgeons must be accurately constructed and capable of faultless operation since there is no room for error in their performance. Moreover, these devices must be made so that, if they are disassembled to be cleaned in an autoclave, they can be reassembled without any risk of inaccurate or faulty operation after reassembly. Moreover, such disassembly and reassembly must be sufficiently uncomplicated that it can be carried out by persons who are not normally concerned with the repair and maintenance of sophisticated mechanical equipment.
It is of further importance that equipment of the type disclosed herein be constructed so that the parts which perform the cutting or other operations, and accordingly must be replaced from time to time, be made and assembled so that they can be quickly and easily replaced, even during the performance of an operation.
Accordingly, a primary object of this invention is the provision of a handpiece adapted for connection to, and operation by, a source of rotational power and also adapted for holding and actuating a variety of different tools such as osteotomes, saws having oscillating blades and saws having reciprocating blades.
A further object of this invention is the provision of a handpiece, as aforesaid, which has the capability of utilizing parts which can be inventoried and used for a variety of different handpieces and which can be readily disassembled and assembled as required for cleaning.
A further object of this invention is the provision of a handpiece, as aforesaid, which is adapted for connection to and actuation by either the output shaft of an air motor or a flexible cable connected to an electric motor.
A further object of this invention is the provision of a handpiece, as aforesaid, which is relatively light in weight and small.
in size so that it can be easily handled by the physician for extended periods of time without creating a condition of fatigue.
Other objects and purposes of this invention will become apparent to persons familiar with this type of equipment upon reading the following descriptive material and examining the accompanying drawings, in which:
FIG. 1 is a side elevational view of a handpiece embodying the invention and connected to a fragment of an air motor and to an osteotome.
FIG. 2 is an enlarged sectional view substantially as taken along the line llII in FIG. I.
FIG. 3 is a perspective view of the input drive and crank mechanisms.
FIG. 4 is an exploded perspective view of the input drive and crank mechanisms, along with the parts of the handpiece housing in which they are located.
FIG. 5 is an exploded view of the output mechanism of the said handpiece and the associated portion of the handpiece housing.
FIG. 6 is a sectional view taken along the line VIVI in FIG. 1.
FIG. 7 is a sectional view taken along the line VII-VII in FIG. 1.
FIG. 8 is an enlarged sectional view taken along the line VIII-VIII in FIG. 1.
FIG. 9 is a sectional view taken along the line IX-IX in FIG. 2.
FIGS. 10, I2 and ll, 13 are side and top views, respectfully of a pair of osteotomes.
FIG. 14 is a side view of a segment of a handpiece including the part thereof which is modified for adaptation to the operation of an oscillating saw.
FIG. 15 is a sectional view taken along the line XVXV in FIG. 14. I
FIG. 16 is an enlarged sectional view taken along the line XVI-XVI in FIG. 15. I
FIG. 17 is a sectional view taken along the line XVIIXVII in FIG. 16.
For convenience in description, the terms front," driven, or output and rear, drive, or input," or words of similar import, will have reference to the left and right ends, respectively, of the handpieces as appearing in FIGS. 1, 2 and 14. The words inner," outer and derivatives thereof will have reference to the geometric center of said handpieces and parts thereof.
SUMMARY OF THE INVENTION The objects and purposes of the invention, including those set forth above, have been met by providing a handpiece having an elongated tubular housing which is connectable at one end either to an air motor or to a housing for a motor driven cable and which is adapted for supporting a tool such as an osteotome or a saw blade at the'other end thereofpBetween these two are located an input drive mechanism, a crank mechanism and an output driven mechanism whereby the rotational force of the motor or cable is converted into a reciprocation for driving the osteotome or the saw.
The handpiece housing has drive and driven sections which are connected to a central crank section in which the crank mechanism is mounted for converting the rotary drive motion into the reciprocating driven motion. It will be recognized that, while the driven and drive sections are shown to be coaxial in this embodiment, some other angular relationship therebetween could be effected by appropriate modification of the crank section of the housing.
DETAILED DESCRIPTION one end with an enlarged housing portion 17 defining the crank section 12. An opening 18 (FIG. 4) extends through the center of the housing 17 transaxially of the tubular housing II and communicates with an opening 19 which extends lengthwise through the sleeve 16.
The crank section 12 (FIG. 4) includes a pair of bearing supporting caps 20 and 21 which are secured to the enlarged housing portion l7 to cover the opposite ends of the opening 18. A pair of seal rings 22 and 23 are provided between the housing portion 17 and the end caps 20 and 21, respectively. In this particular embodiment, the end cap 20 (FIG. 2) has a recess 24 in the inner surface thereof for receiving a bearing assembly 25. The end cap 20 is secured to the enlarged housing portion 17 by a plurality of screws 26. Similarly, the end cap 21 has a recess 27 in the inner surface thereof and is adapted to receive a bearing assembly 28. The recesses 23 and 27 and the bearing assemblies 25 and 28 are coaxial. Screws 29 secure the end caps 21 to the housing 17.
A bevel gear 31 (FIG. 2) has a coaxial, integral sleeve 32 which has a coaxial opening 33 and is rotatably mounted in the bearing assembly 25. A spacer 34 is provided between the bevel gear 31 and the inner race of the bearing assembly 25 to permit the bevel gear 31 to freely rotate relative to the end cap 21.
the opening 33 and is rigidly secured to sleeve 32 by any convenient means, such as a press fit. The crankshaft 36 has an integral crank 37 between the ends thereof. In this particular embodiment, wear rings or spacers 38 and 39 are mounted on the crankshaft 36 on opposite sides of the crank 37. The upper end of the crankshaft 36 extends through the spacer 39 and is rotatably supported in the bearing assembly 28.
The enlarged annular end portion 41 (FIGS. 2 and 4) of a connecting rod 42 is rotatably mounted upon the crank 37 of the crankshaft 36 between the spacers 38 and 39. The internal surface of the end portion 41 is separated from the crank 37 by a needle bearing assembly 44. An integral, cylindrical pin 46 extends laterally of the connecting rod 42 remote from the end portion 41 and in a direction preferably parallel with the axis of the crankshaft 36.
The drive section 13 of the tubular housing 11 contains a cylindrical bearing retainer 47 which supports a pair of coaxial, spaced bearings 48 and 49 at the opposite ends thereof. The bearing retainer 47 is slidably received into the opening 19 in. the drive section 13 and has an annular groove 50 between its endsinto which a set screw 52 is received to hold the retainer 47 in a fixed location. A shaft 53 is rotatably supported in the bearings 48 and 49.
The left end (FIG. 2) of the shaft 53 extends into the crank section 12, and a bevel gear 54is fixedly secured to and rotatable with the shaft. 53. The gear 54 is in meshing engagement with the bevel gear 31 on the crankshaft 36. The drive or rightward end of the shaft 53 (FIG. 2) is secured to a coupling member 56 which is engageable with a cooperating coupling member 57 on a power source 60. More particularly, the coupling member 56 has spaced and parallel fingers 58 which define a pair of transverse slots 59 (FIGS. 2, 3 and 4). The coupling member 57 comprises a pin on the output shaft 61 of an air motor, for example. The pin 57 is received into one of the transverse slots 59 in the coupling member 58 to rotatably drive the shaft 53.
The rightwardmost end of the drive section 13 is provided with an internal thread at 63. The left end of the air motor housing 62 is provided with an external thread at 64 which is threadedlyengaged with the thread 63 on the drive section 13 to secure the air motor 60 to the hand held device 10.
An opening 66 is provided in the crank housing portion 17 and communicates with the opening 18. The opening 66, which is internally threaded, is axially aligned with the opening 19 in the drive section 13. It is recognized, however, that the opening 66 could be oriented transversely to the axis of the opening 19 in the drive section 13.
HANDPIECE WITH OSTEOTOME (FIGS. l13) The driven section 14 of the device is secured to the crank section 12 of the housing 11 and is adapted to support a tool or instrument. In this particular embodiment, the section 12 comprises a cylindrical tool housing 71 having a central opening 72 therethrough and an external thread 73 at the rightward end (FIG. 2) which is capable of threadedly engag- The lower end (FIG. 2) of the crankshaft 36 extends into ing the internally threaded opening 66. A sea] 74 is provided in an annular groove 76 in the housing 71 and is adapted to sealingly engage the internal surface of the opening 66 to prevent the escape of contaminents from the crank section 12. A set screw 77 (FIG. 4) is received in a threaded opening 78 to releasably hold the housing 71 against rotation with respect to the crank section 12.
The end of the housing 71 remote from the thread 72 is reduced in diameter and provided with an external thread 81. An integral, annular flange 82 extends radially inwardly at the left end of housing 71 to define an opening 83 which is smaller in diameter than the opening 78 and coaxial therewith.
A slot 84 (FIGS. 2 and 5) is provided in the left end of the housing 71, which also has radially disposed, threaded opening 86'adjacent the left end of the housing 71 and communicating with the opening'78.
A pair of sleeve bushings 87 and 88 are slidably received in the opening 78 in the housing 71 and are axially spaced from each other by a seal member, here an Oring 89. An elongated shaft 91 is slidably, received in the opening 92 through the bushings 87 and 88 and has at the right end thereof a narrowed portion 93 with a'transverse opening 94 therethrough. The opening 94 is adapted to receive the pin 46 on the connecting rod 42 to pivotally connect the shaft 91 to the connecting rod 42 to pivotally connect the shaft 91 to the connecting rod 42. Thus, rotational movement of the crankshaft 36 will result in an axial reciprocation of the shaft 91 in the bushings 87 and 88.
A cup-shaped end cap 96 having an internal thread 97 is threaded into the external thread 81 of the housing 71. An
opening 101 is provided in the end wall 102 of the end cap 96 1 and has a diameter generally equal to the diameter of the opening 83. The wall 102 has a pair of diametrically opposed notches 103 and 104 (FIG. 6) which extend radially outwardly from the opening 101.
A split sleeve 106 having a central opening 107 therethrough is mounted over the left end of the housing 71 and the right end of the end cap 76 which are both reduced in diameter to receive said sleeve. The sleeve 106, which resiliently grips the cap 96, is held against rotation by a screw 108 which is disposed in a recess 1 10 in the edge of the cap 96 and which is threadedly received in the threaded opening 86 in the housing 71. The recess 110 is of sufficient circumferential length to permit a degree rotative movement of the cap 96 relative to the cylindrical housing 71. A bushing 109 is provided around the screw threads of the screw 108 to prevent direct engagement between the cap edge and the screw 108, and also to space the sleeve from the housing 71 near said screw.
A tool, here an osteotome 111, comprises an elongated anvil 1 12 (FIG. 2) having a slightly smaller diameter than that of the bushing 87. A transverse pin 113 extends transaxially through and beyond the anvil portion 112 and the opposite ends thereof are slidably disposed in the slot 84 in the left end of the housing 71. The length of the pin 113 is less than the combined length of the opening 101 and the notches 103 and 104 so that, when the end cap 96 is rotated until the notches 103 and 104 are aligned with the slotted end 84 in the housing 71, the tool 111 can be withdrawn from the tool housing 71 by pulling axially outwardly on the tool 111. A new tool (osteotome) 111A or 1118 (FIGS. 1013) may be inserted into the tool housing by following a reversed procedure, after which the cap 96 is rotated to prevent accidental removal of said tool.
Where tools 111 (FIG. 1), 111A (FIGS. 10-11) or 111B (FIGS. 12-13) are of the osteotome variety, pressure of the tool against the material which is being worked upon urges the tool rightwardly into engagement with the left end of the shaft or hammer 91. The spacing between the end wall 102 of the end cap 96 and the annular flange v82 of the housing 71, against which the pin 113 on the tool 111 strokes, defines the maximum limit of the reciprocable movement of the tool 111. However, when the tool 111 is urged into engagement with the work, the engagement between the anvil 112 and the hammer 91 normally prevents the pin 113 from engaging the annular flange 82. Moreover, the engagement of the tool with the work, such as a bone, minimizes the amount of engagement between the pin 113 and the end wall 102 during normal operation.
SAGI'ITAL SAW HANDPIECE (FIGS. 14-17) The modified driven section 121 (FIG. 14) of the handpiece A for holding a sawblade 122 is in the form of an elongated tubular housing which, in this particular embodiment, comprises a first cylindrical member 124 having an external thread 126 at one end thereof cooperable with the internal thread 67 in the crank section 12 of the device 10. An internal thread 127 is provided at the end remote from the external thread 126. A second cylindrical member 128 has an enlarged rightward end with an external thread 129 engageable with the internal thread 127 on the first cylindrical member 124.
A flange 131 is integral with the left end of the second cylindrical member 128 and extends radially or downwardly therefrom. The end wall 125 of the second cylindrical member 128 has a diametrical slot 130 which extends axially into the member 128 and into the flange 131.
A pair of openings 132 and 133 extend laterally through the flange 131, as illustrated in FIG. 17. The opening 132 is spaced above, and rightwardly of, the opening 133, which passes through the slot 13. One end of the opening 132 is recessed at 134 (FIG. 17).
A U-shaped pin 136, having parallel leg members 137 and 138 and an interconnecting portion 139, is mounted on the flange 131. The spacing between the legs 137 and 138 is equal to the spacing between the openings 132 and 133 so that the legs 137 and 138 will be simultaneously receivable into the openings 132 and 133. If desired, the interconnecting portion 139 may be received in an elongated slot 141 which extends between the opening 132 and the opening 133 along one side of the flange 131, as illustrated in FIG. 17. The leg 137 of the U-shaped pin 136 is preferably longer than the leg 138 and has a head 142 on the free end thereof. A spring 143 is sleeved upon the leg 137 and held under compression with one end thereof being received in the recess 134 and the opposite end thereof resting against the head 142. Thus, the U-shaped pin member 136 will be urged rightwardly (FIG. 17) so that the leg 138 will normally extend across the slot 130.
A bushing 151 (FIG. and an annular seal 152 are mounted within the first cylindrical member 124 of the driven section 121. The bushing 151 has a central opening 153 through which a shaft 154 is slidably received for reciprocable motion. The rightward end of the shaft 154 has an axial extension 156 with a transverse opening 157 therethrough. The pin 46 on the connecting rod 42 is received in the opening 157 to secure the shaft 154 pivotally to the connecting rod 42.
The left end of the shaft 154 is of reduced diameter, but is has an enlarged end portion 158 which is slotted diametrically at 159. The slot 159 is alignable with the slot 147 in the tool housing 121.
A diametrical opening 161 in the enlarged end portion 158 extends perpendicularly through the slot 259 and a pin 162 is disposed in said opening 161. A bushing 163 is mounted on the pin 162 and is disposed within the slot 159.
The saw blade 122 (FIG. 16) is elongated, flat and has upwardly converging lengthwise edges. The bottom edge of the blade is arcuate and has saw teeth 166 thereon. An opening 167 is provided in the central region of the saw blade 122 and is coaxial with the arcuate bottom edge of the saw blade 122. A notch 168 is provided at the upper end of the saw blade 122, which end can be received into the slot 147 in the end of the tool housing 121. The blade upper end can also be received into the slot 159 in the end of the shaft 154, so that pin 162 in the enlarged end portion 158 is received into the notch 168 of the saw blade 122.
However, before the blade 122 is thusly mounted, the leg 138 of the U-shaped pin 136 will normally be moved leftwardly (FIG. 17) by depressing the head 142 against the flange 131 whereby the leg 138 is moved leftwardly of the slot 147. Once the opening 167 in the saw blade 122 becomes aligned with the opening 133 in the flange 131, the force applied to the head 142 can be released to permit a rightward movement of the leg 138 under the urging of the spring 143 into the opening 167 of the saw blade 122 to pivotally support the saw blade 122 upon the tool housing 121 and in engagement with the shaft 154.
OPERATION Although the operation of the power driven, hand held device 10 described above will be understood from the foregoing description by skilled persons, a brief summary of such operation is given hereinafter for convenience.
HANDPIECE WITH OSTEOTOME An osteotome, such as one of those identified as 1 11, 111A or 1118, is mounted in the driven section 14 of handpiece 10, as discussed above. Appropriate rotational power is applied to the shaft 53, as by the air motor 60 (FIG. 3) in this embodiment, which acts through the coupling members 56 and 57. Rotation of the shaft 53 will act through the bevel gears 54 and 31 to rotate the crankshaft 36, hence the crank 37. The crank will cause the connecting rod 42- to reciprocate the hammer 91 axially of the hand held device 10.
The osteotome is pressed against the work, as a bone, until the anvil 112 engages the hammer 91. Thus leftward movement of the hammer 91 will cause an engagement thereof with the anvil 112 whereby its cutting end is abruptly urged against the work. As long as the osteotome is urged into engagement with the bone upon which work is being performed, the continued reciprocation of the shaft 91 will continue to hammer the anvil.
If it is desired to replace one tool 111 with one of the tools 111A (FIGS. 10, 11) or 1118 (FIGS. 12, 13), the end cap 96 is rotated from the position illustrated in FIG. 6 to a position spaced therefrom so that the notches 103 and 104 will become aligned with the slot 84 in the end of the tubular housing 71. The pin 1l3can then be slid through the notches 103 and 104 and removed from the tool or instrument housing 71. A new tool 111A or 111B may be inserted into the tool housing 71 by reversing the foregoing procedure.
SAGI'ITAL SAW I-IANDPIECE v will sever a bone or plaster cast without damaging adjacent human tissue.
Although particular preferred embodiments of the invention have been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.
The embodiments of the invention in which an exclusive property or'privilege is claimed are defined as follows:
1. A power driven, hand held device for actuating a tool, comprising:
an elongated, substantially tubular housing having a crank section, a drive section and a driven section, said drive and driven sections being substantially coaxial and extending outwardly away from opposite sides of said crank section;
releasable connecting means coacting between said drive and driven sections and said crank section for releasably rigidly securing said drive and driven sections to said crank section, said drive and driven sections being individually separable from said crank section;
a drive shaft rotatably supported within said drive section and having coupling means at the end thereof remote from the crank section and adapted for engagement with and rotation by power means;
a crankshaft rotatably supported within said crank section for rotation around an axis transverse of the rotational axis of said drive shaft, said crankshaft having a crank between the ends thereof;
said crank section having a pair of removable cover plates on opposite sides thereof having coaxial circular recesses in the opposing faces thereof, and bearing means disposed in said recesses for rotatably supporting the ends of said crankshaft;
gearfmeans connected between said crankshaft and the adjacent end of said drive shaft for effecting rotation of said crankshaft in response to rotation of said drive shaft;
a connecting rod journaled on said crank for relative rotation with respect thereto; and
elongated tool means having elongated shaft means slidably disposed within and confined by said driven section whereby said shaft means is solely movable in the lengthwise direction of said driven section, said shaft means being pivotally connected at one end to said connecting rod whereby rotation of said crankshaft causes a corresponding linear reciprocation of said shaft means.
2. A device according to claim 1, including an air motor mounted on the end. of said drive section remote from the crank section and drivingly connected to said coupling means.
3. A device accordingto claim 1, wherein said shaft means includes a first shaft pivotally connected adjacent one end thereof to said connecting rod and a second shaft disposed adjacent the other end of said first shaft, said first and second shafts being movable with respect to each other and engageable at their adjacent ends; and I first stop means on said second shaft and second stop means on said driven section, said first and second stop means being engageable for limiting movement of said second shaft away from said first shaft, whereby rotation of said crankshaft causes said first shaft to hammer against the adjacent end of the second shaft.
4. A device according to claim 1, wherein said connecting rod and said shaft means have opposed portions which overlap one another in the longitudinal direction of said driven section, one of said portions. having a cantilevered pin projecting outwardly therefrom in a direction substantially perpendicular to the longitudinally extending direction of said driven section, the other portion having a recess formed therein for receiving therein said pin to pivotally connect said connecting rod to said shaft means, whereby said shaft means is readily detachable from said connecting rod when said housing means is disassembled.
5. A device according to claim 1, further including an end cap and means releasably but fixedly securing said end cap to the free end of said driven section, said last-mentioned means permitting said end cap to be rotated relative to said driven section substantially about the longitudinally extending axis thereof, said end cap having a central opening extending therethrough substantially coaxially aligned with the opening defined by said driven section, said end cap also having a radially extending slot extending outwardly of said opening, and said driven section including wall means provided adjacent the free end thereof and defining a radially outwardly and axially extending slot disposed for alignment with the slot formed in said end cap when said end cap is in a first angular position, whereby rotation of said end cap to a second angular position causes said slots to be disposed in a nonaligned relationship, and said elongated tool means including an elongated shaftlike tool having one end thereof adapted to be slidably disposed through said end cap and into the free end of said driven section, said shaftlike tool having a radially extending projection adjacent the end thereof for insertion through said slots when same are aligned, whereby rotation of said end cap to said second position causes said tool to be locked within said driven section.
6. A power driven, hand held device for actuating a tool.
an elongated, substantially tubular housing having a crank section, a drive section and, a driven section, said drive and driven sections being rigidly secured to and extending away from said crank section;
a drive shaft rotatably supportedwithin said drive section and having coupling means at the end thereof remote from the crank section and adapted for engagement with and rotation by power means;
a crankshaft rotatably supported within said crank section for rotation around an axis transverse-of the rotational axis of said drive shaft, said crankshaft having a crank between the endsthereof;
gear means connected between said crankshaft and the adjacent end of saiddrive shaft for eflecting rotation of said crankshaft in response to rotation of said drive shaft;
a connecting rod journaled on said crank for relative rotation with respect thereto;
elongated tool means having elongated'shaft means slidably disposed within said driven section I for movement lengthwise thereof, said shaft means being pivotally connected at one end to said connecting rod; 1
said driven section having, at the end thereof remote from 1 the crank section, integral flange means ally therefrom; said shaft means having pin means secured thereto and extending transversely of said flange means adjacent thereto; and I blade means pivotally mounted upon said flange means for movement around an axis spaced from said shaft means, said blade means being pivotally-connected near one edge thereof to said pin means, theopposite edge of said blade means having cutting means thereon;
whereby rotation of said crankshaft acts through said shaft means to effect oscillation of said blademeans.
7. A device according to claim 6, wherein said one edge of said blade means is bifurcated for removable engagement with said pin means; and including substantially U-shaped pivot shaft means, one leg of which slidably extends through openings in said flange means and said blade means, the other leg thereof extending through an opening in said driven section, said other leg having head means and being substantially longer than said one leg; and
projecting radiresilient means extending between said head and said driven v section for yieldably holding said one leg within said openings in said flange means and said blade means. 8. A handpiece adapted to drivingly connect tool means to power means, comprising:
substantially tubular housing means; crank means rotatably supported within said housing means for rotation around an axis transverse thereof; drive means connected to said crank means for effecting rotation thereof, said drive means also being adapted for connection to said power means; articulated connecting rod means journaled at one end on said crank means and extending away therefrom through said housing means for reciprocating movement therein; flange means on said housing means remote from said crank means and extending laterally therefrom; elongated blade means pivotally mounted approximately midway between the ends thereof upon said flange means; pivot means connecting said blade means to the end of said connecting rod means remote from said crank means whereby rotation of said crank means acts through said connecting rod means to oscillate said blade means.