U.S. patent number 3,678,934 [Application Number 05/063,460] was granted by the patent office on 1972-07-25 for power osteotome.
This patent grant is currently assigned to Stryker Corporation. Invention is credited to Russell K. Eaton, Wayne N. Warfield.
United States Patent |
3,678,934 |
Warfield , et al. |
July 25, 1972 |
POWER OSTEOTOME
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.
Inventors: |
Warfield; Wayne N. (Kalamazoo
Township, Kalamazoo County, MI), Eaton; Russell K.
(Kalamazoo Township, Kalamazoo County, MI) |
Assignee: |
Stryker Corporation (Kalamazoo,
MI)
|
Family
ID: |
22049352 |
Appl.
No.: |
05/063,460 |
Filed: |
August 13, 1970 |
Current U.S.
Class: |
606/79; 74/44;
74/606R; 606/177; 74/25; 74/104; 606/84; 606/178 |
Current CPC
Class: |
B23D
51/18 (20130101); B23D 51/16 (20130101); B27B
19/006 (20130101); A61B 17/1624 (20130101); Y10T
74/18936 (20150115); Y10T 74/2186 (20150115); Y10T
74/18208 (20150115); Y10T 74/18056 (20150115) |
Current International
Class: |
A61B
17/16 (20060101); B27B 19/00 (20060101); B23D
51/00 (20060101); B23D 51/16 (20060101); B23D
51/18 (20060101); A61b 017/14 (); A61b 017/16 ();
F16h 057/02 () |
Field of
Search: |
;74/25,44,104,606
;128/310,317 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pace; Channing L.
Claims
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;
gear means 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 according to 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
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,
comprising:
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 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;
gear means 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;
elongated tool means having elongated shaft means slidably disposed
within said driven section for movement lengthwise thereof, said
shaft means being pivotally connected at one end to said connecting
rod;
said driven section having, at the end thereof remote from the
crank section, integral flange means projecting radially
therefrom;
said shaft means having pin means secured thereto and extending
transversely of said flange means adjacent thereto; and
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, the
opposite edge of said blade means having cutting means thereon;
whereby rotation of said crankshaft acts through said shaft means
to effect oscillation of said blade means.
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
resilient means extending between said head and said driven 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.
Description
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.
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 equally adaptable for use in
fields other than medicine, such as woodworking.
Heretofore, 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 II--II in FIG. 1.
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 VI--VI 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, 12 and 11, 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 XV--XV in FIG.
14.
FIG. 16 is an enlarged sectional view taken along the line XVI--XVI
in FIG. 15.
FIG. 17 is a sectional view taken along the line XVII--XVII 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 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.
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
A power driven, hand held device 10 for actuating a surgical tool
or instrument comprises an elongated, substantially tubular housing
11 having a crank section 12, a drive section 13 and driven section
14, said drive and driven sections extending away from the crank
section 12 in opposite directions. More particularly, the drive
section 13 of the tubular housing 11 comprises a hollow cylindrical
sleeve 16 which is integral at 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 11 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 17
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 lower end (FIG. 2) of the crankshaft 36 extends into 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 ends into 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 54 is 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 threadedly engaged
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. 1--13)
The driven section 14 of the device 10 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 engaging the internally threaded
opening 66. A seal 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 O-ring 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 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 110
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 90 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 112
(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 111B (FIGS. 10-13) 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
82 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.
SAGITTAL SAW HANDPIECE (FIGS. 14-17)
The modified driven section 121 (FIG. 14) of the handpiece 10A 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. 15) 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 z59 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 111, 111A or 111B,
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 111B (FIGS. 12, 13), the end cap 96 is rotated
from the position illustrated in FIG. 6 to a position 90.degree.
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 113 can 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.
SAGITTAL SAW HANDPIECE
The connecting rod 42 (FIG. 15) is driven in the same manner as
described above with respect to the Handpiece With Osteotome.
Reciprocation of the shaft 154 by the connecting rod 42 will result
in transaxial reciprocation of the pin 162, hence, oscillation of
the saw blade 122 (FIG. 16). Thus, the saw teeth 166 will oscillate
around the axis of the leg 138 of the U-shaped pin 136. The
reciprocating stroke of the shaft 154 is such that the resulting
movement of the saw teeth 166 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.
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