U.S. patent application number 09/756423 was filed with the patent office on 2001-06-28 for torque indicator ratchet wrench for dentistry.
Invention is credited to Robb, Thomas Tait, Rogers, Dan Paul.
Application Number | 20010005576 09/756423 |
Document ID | / |
Family ID | 26811093 |
Filed Date | 2001-06-28 |
United States Patent
Application |
20010005576 |
Kind Code |
A1 |
Rogers, Dan Paul ; et
al. |
June 28, 2001 |
Torque indicator ratchet wrench for dentistry
Abstract
This present invention relates to a ratchet wrench and a torque
indicator combined concentrically in a single housing. The ratchet
wrench is useful for driving a fastener used in dentistry, such as
an abutment screw that holds an abutment on a dental implant. In
operation, the handle of the wrench can be rotated in one direction
(e.g. clockwise) to impart torque on the fastener. When the handle
is rotated in the opposite direction (e.g. counterclockwise), no
torque is applied to the fastener as the handle is returned to a
position where it is easy for the clinician to again rotate the
handle to apply additional torque to the fastener. The return
motion of the handle (e.g. counterclockwise rotation) may be
stepless in operation which is brought about through a coiled
clutch spring located in an annular space within a housing between
the housing and a concentric driver member. To provide an
indication of torque, a rotor body is supported coaxially within
the driver member. Torque indicator marks on the rotor body and the
driver member indicate angular displacement of the driver member
around the common axis relative to the rotor body when a tool held
in the rotor body is restrained from turning under load. The
housing and with it the drive member may be turned by hand around
their common axis when the housing is turned in the latched
direction, or a handle fixed to the housing may be used. A
lubricating washer is supplied to reduce friction within the
ratchet wrench.
Inventors: |
Rogers, Dan Paul; (Royal
Palm Beach, FL) ; Robb, Thomas Tait; (Stuart,
FL) |
Correspondence
Address: |
JENKENS & GILCHRIST, PC
1445 ROSS AVENUE
SUITE 3200
DALLAS
TX
75202
US
|
Family ID: |
26811093 |
Appl. No.: |
09/756423 |
Filed: |
January 8, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09756423 |
Jan 8, 2001 |
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09470555 |
Dec 22, 1999 |
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6186785 |
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60113463 |
Dec 23, 1998 |
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60136516 |
May 28, 1999 |
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Current U.S.
Class: |
433/141 ;
433/173 |
Current CPC
Class: |
B25B 23/1422 20130101;
A61C 1/186 20130101; A61C 8/0089 20130101; B25B 23/0035 20130101;
B25B 13/462 20130101 |
Class at
Publication: |
433/141 ;
433/173 |
International
Class: |
A61C 008/00 |
Claims
1. A dental ratchet wrench for applying torque to a fastener that
is used in a dental prosthesis, comprising: a housing; a drive
member located within said housing; a slip clutch spring coupled to
said housing and said drive member, said slip clutch spring causing
said drive member to rotate with said housing when said housing is
rotated in one direction, said slip clutch spring causing said
drive member to rotate relative to said housing when said housing
is rotated in the opposite direction; a rotor coupled to said drive
member via a straight coil torsion spring, said rotor including
means for receiving a tool for rotating said fastener; and torque
indicators on at least one said drive member and said rotor at
known angular positions corresponding to predetermined torque
values, said torque indicators progressively illustrating the
amount of torque being exerted by said rotor.
2. The dental ratchet wrench of claim 1, wherein said housing and
said driving member define a region having an annularly shaped
cross-section, said annularly shaped cross-section having a
narrower portion.
3. The dental ratchet wrench of claim 2, wherein said narrower
portion is dimensioned to catch a free end of said slip clutch
spring when said housing is rotated in said one direction, while
allowing said free end to rotate with respect to said housing when
said housing is rotated in said other direction.
4. The dental ratchet wrench of claim 1, wherein said torsion
spring has two free ends that extend in the axial direction with
respect to said housing.
5. The dental ratchet wrench of claim 1, wherein said rotor
includes a lower hub, said torsion spring being connected to said
lower hub and passing internally through said drive member to an
upper flange of said rotor, said torsion spring being connected to
said upper flange.
6. The dental ratchet wrench of claim 1, wherein said rotor and
said drive member have complementary confronting surfaces that
rotate relative to each other, said dental ratchet wrench further
including a lubricating region between said confronting surfaces
for reducing friction.
7. The dental ratchet wrench of claim 6, wherein said rotor and
said drive member each have lower hubs, said complementary
confronting surfaces being located on said lower hubs.
8. The dental ratchet wrench of claim 7, wherein said lubricating
region is a washer is made of Teflon.
9. The dental ratchet wrench of claim 8, wherein said torque
indicators are placed on said dental ratchet wrench before final
assembly.
10. The dental ratchet wrench of claim 1, wherein said receiving
means includes at least two different regions for receiving two
types of tools.
11. The dental ratchet wrench of claim 10, wherein a first region
includes a polygonal socket and a second region includes an
ISO-type tool holder.
12. The dental ratchet wrench of claim 11, wherein said second
region is accessible by an ISO-type tool by extending said ISO-type
tool through said first region.
13. A dental ratchet wrench for applying a known amount of torque
to a fastener that is used in a dental prosthesis, comprising: a
housing; a drive member located primarily within said housing, said
housing and said drive member defining a first region therebetween;
a tool receiving component for receiving a tool to exert torque on
said fastener, said tool receiving component located primarily
within said drive member, said tool receiving component and said
drive member defining a second region; a torsion spring located
within said second region, said torsion spring having one end
connected to said drive member and the other end connected to said
tool receiving component, a certain angular displacement of said
one end relative to said other end producing a certain torque on
said tool receiving component; a slip clutch located within said
first region, said slip clutch causing said drive member to rotate
with said housing when said housing is rotated in one direction,
said slip clutch causing said drive member to rotate relative to
said housing when said housing is rotated in the opposite
direction; and torque indicators on at least one of said drive
member and tool receiving component corresponding to predetermined
torque values, said torque indicators progressively illustrating
the amount of torque being exerted by said tool receiving
component.
14. The dental ratchet wrench of claim 13, wherein said first
region has an annularly shaped cross-section, said annularly shaped
cross-section having a narrower portion.
15. The dental ratchet wrench of claim 14, wherein said slip clutch
is a spring and said narrower portion is dimensioned to catch a
free end of said spring when said housing is rotated in said one
direction, while allowing said free end to rotate with respect to
said housing when said housing is rotated in said other
direction.
16. The dental ratchet wrench of claim 13, wherein said tool
receiving portion includes a lower hub and said drive member has an
upper flange, said lower hub and said upper flange at least
partially defining said second region, said one end of said torsion
spring being connected to said lower hub and said other end of said
torsion spring being connected to said upper flange of said
rotor.
17. The dental ratchet wrench of claim 13, wherein said tool
receiving portion and said drive member have complementary
confronting surfaces that rotate relative to each other, said
complementary confronting surfaces including a lubricating region
for reducing friction.
18. The dental ratchet wrench of claim 17, wherein said lubricating
region includes a washer that is made of Teflon.
19. The dental ratchet wrench of claim 13, wherein said tool
receiving portion has two distinct portions for receiving two
distinct tools.
20. The dental ratchet wrench of claim 19, wherein a first portion
includes a polygonal socket and a second portion includes an
ISO-type tool holder.
21. The dental ratchet wrench of claim 13, wherein said torsion
spring has two free ends that extend in the axial direction.
22. The dental ratchet wrench of claim 13, wherein said tool
receiving portion includes an ISO-type tool holder.
23. The dental ratchet wrench of claim 22, wherein said ISO-type
tool holder includes a cylindrical body having a plurality of
cut-outs and a spring for wrapping around said body, portions of
said spring extending within said cut-outs.
24. The dental ratchet wrench of claim 23, wherein said spring has
a D-shape.
25. The dental ratchet wrench of claim 23, wherein said spring is a
coil spring.
26. The dental ratchet wrench of claim 22, wherein said ISO-type
tool holder includes a rotatable latch for locking the tool in
place.
27. The dental ratchet wrench of claim 22, wherein said ISO-type
tool holder includes a cylindrical detent within one of said
cut-outs.
28. The dental ratchet wrench of claim 13, wherein a diameter of
said housing is less than about 0.75 inch.
29. The dental ratchet wrench of claim 13, wherein said torsion
spring is made of a stainless steel.
30. The dental ratchet wrench of claim 29, wherein said torsion
spring is made of stainless steel wire stock having a diameter of
about 1.25 mm.
31. The dental ratchet wrench of claim 13, wherein said torque
indicators includes a plurality of torque-number markings on said
drive member and one marking on said tool receiving component, said
one marking on said tool receiving component moving relative to
said plurality of torque-number markings while said torque is being
exerted.
32. The dental ratchet wrench of claim 13, wherein said tool
receiving component has upper and lower tool receiving portions
allowing said wrench to be used to reverse the torque on said
screw.
33. A dental wrench for applying torque to a fastener used in a
dental prosthesis, comprising: a housing; a drive member located
primarily within said housing; a tool receiving component coupled
to and located adjacent to said drive member, said tool receiving
component for receiving a tool to exert torque on said fastener,
said tool receiving component including an ISO-type tool holder for
holding a dental tool having an ISO-type latch; and torque markings
representing corresponding torque values on at least one of said
drive member and said tool receiving component.
34. The dental ratchet wrench of claim 33, wherein said ISO-type
tool holder includes a cylindrical body having a plurality of
cut-outs and a spring for wrapping around said body, portions of
said spring extending within said cut-outs.
35. The dental ratchet wrench of claim 34, wherein said spring has
a D-shape.
36. The dental ratchet wrench of claim 34, wherein said spring is a
coil spring.
37. The dental ratchet wrench of claim 33, wherein said ISO-type
tool holder includes a rotatable latch for locking the tool in
place.
38. The dental ratchet wrench of claim 33, wherein said ISO-type
tool holder includes a cylindrical detent within one of said
cut-outs.
39. A ratchet wrench for applying torque to a fastener, comprising:
a drive member; a rotor coupled to and located adjacent to said
drive member, said rotor for exerting said torque on said fastener;
a ratcheting mechanism allowing said drive member to move said
rotor in one direction; and a plurality of torque markings
representing corresponding torque values on at least one of said
drive member and said rotor, said torque markings progressively
illustrating the torque that said rotor places on said
fastener.
40. The ratchet wrench of claim 39, wherein said plurality of
torque markings includes a plurality of torque-number markings on
said drive member and a single marking on said tool receiving
component, said single marking on said rotor moving relative to
said plurality of torque-number markings while said torque is being
exerted.
41. The ratchet wrench of claim 39, wherein said rotor and said
drive member are coupled through a straight coil torsion spring
located between said rotor and said drive member.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a complete application claiming the benefit of
Provisional Applications No. 60/113,463, filed Dec. 23, 1998, and
No. 60/136,516, filed May 23, 1999.
FIELD OF THE INVENTION
[0002] This present invention relates to a ratchet wrench that
includes a torque indicator that progressively indicates the amount
of torque that is be exerted on the screw or bolt each time the
wrench is rotated and then ratcheted back to its starting position.
In particular, the present invention relates to dental ratchet
wrench with torque indication for dentistry.
BACKGROUND OF THE INVENTION
[0003] While ratchet wrenches have been used in the previously used
in various fields including dentistry, it is particularly useful to
know the amount of torque that each partial rotation and subsequent
ratcheting of the wrench places on the screw or bolt. Thus, unlike
a torque limiter, which does not allow the torque to exceed a
certain amount, a need exists for a ratchet wrench having a torque
indicator that progressively indicates the torque as it is being
exerted on the bolt or screw. Further, a need exists for this
device to be located in a relatively small housing especially when
it is to be used in small regions, such as in the mouth.
SUMMARY OF THE INVENTION
[0004] This specification describes a ratchet wrench and a torque
indicator combined concentrically in a single housing. The ratchet
wrench is useful for driving a fastener used in dentistry, such as
an abutment screw which holds an abutment on a dental implant. In
operation, the handle of the wrench can be rotated in one direction
(e.g. clockwise) to impart torque on the fastener. When the handle
is rotated in the opposite direction (e.g. counterclockwise), no
torque is applied to the fastener as the handle is returned to a
position where it is easy for the clinician to again rotate the
handle to apply additional torque to the fastener.
[0005] The return motion of the handle (e.g. counterclockwise
rotation) may be stepless in operation which is brought about
through a coiled clutch spring located in an annular space within a
housing between the housing and a concentric driver member. The
clutch spring has one end fixed to one of the housing and the
driver member and the other end free in the annular space between
them. Preferably, the part of the annular space containing the free
end is thinner than the part of the annular space containing the
fixed end of the clutch spring. Depending on the direction in which
the clutch spring is coiled, its free end will slip in the annular
space when relative rotation around is imparted in one direction
between the housing and the driver member. However, it will latch
the housing and the driver member against relative rotation in the
opposite direction. Alternatively, the return motion of the wrench
can be accomplished by using an overrunning or detent clutch which
provides a "click"-type action.
[0006] To provide an indication of torque, a rotor body is
supported coaxially within the driver member. A torsion spring
located between the rotor body and driving member is fixed at one
end to the rotor body and at its other end to the driving member.
This rotor body is adapted to hold one or more wrench tools in one
or more sockets located on the common axis. Torque indicator marks
on the rotor body and the driver member indicate angular
displacement of the driver member around the common axis relative
to the rotor body when a tool held in the rotor body is restrained
from turning under load. The housing and with it the drive member
may be turned by hand around their common axis when the housing is
turned in the latched direction. Or, a handle fixed to the housing
may be used to turn the housing around the common axis. The torque
indicator marks indicate torque at the axis of rotation of a tool.
The fixed handle does not participate in this measurement, and can
therefore be of a simple, stiff design. The rotor body may be
provided with a receptor for an ISO-type dental latch, as well as a
socket or receptor for another type of tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a longitudinal sectional view of the wrench;
[0008] FIG. 2 is an exploded view of FIG. 1;
[0009] FIG. 3 is a longitudinal sectional view of the housing and
handle of FIG. 1;
[0010] FIGS. 4a and 4b are cross-sectional and end views,
respectively, of the driver member of FIG. 1;
[0011] FIGS. 5a and 5b are cross-sectional and end views,
respectively, of the rotor body of FIG. 1;
[0012] FIG. 5c is an isometric view of the rotor body;
[0013] FIGS. 6a, 6b and 6c are cross-sectional, end and isometric
views, respectively, of the rotor housing hub of FIG. 1;
[0014] FIGS. 6d, 6e and 6f are cross-sectional, end and isometric
views, respectively, of the rotor body hub of FIG. 1;
[0015] FIGS. 7a, 7b and 7c are side, end and isometric views,
respectively, of the clutch spring of FIG. 1;
[0016] FIGS. 8a, 8b and 8c are side, end and isometric views,
respectively, of the torsion spring of FIG. 1;
[0017] FIG. 8d shows another embodiment of the torsion spring;
[0018] FIG. 9 illustrates an "ISO" type dental latch used to
connect dental tools in dental handpieces;
[0019] FIGS. 10a-e are various views, respectively, of the ISO-type
latch body;
[0020] FIGS. 11a-11d show details of the assembled spring and latch
body of the tool holder of FIG. 10;
[0021] FIGS. 12a-12j, inclusive, are a sequence of figures showing
the steps of installing and removing a tool having an ISO-type
latch into and from a holder for such tools;
[0022] FIGS. 13a-13g show a variation of FIGS. 10 and 11 using a
different spring member;
[0023] FIGS. 14a and 14b are sectional views of another ISO-type
tool latch;
[0024] FIG. 15 is an exploded view of FIG. 14;
[0025] FIG. 16 is a longitudinal sectional view of the wrench
including a friction reducing washer;
[0026] FIG. 17 is an exploded view of FIG. 16; and
[0027] FIGS. 18a-18f are various views of an alternative ISO-type
latch body.
DETAILED DESCRIPTION OF THE DRAWINGS
[0028] Referring now to FIGS. 1, 2 and 3, the housing 10 has a
handle 12 attached to a boss 14 at one side of the housing 10. A
drive member 16 is concentrically located within the housing 10
and, together with the housing, defines an annular space 18
containing the coiled clutch spring 20. The drive member 16 and the
clutch spring 20 are shown in greater detail in FIGS. 4 and 7,
respectively.
[0029] The drive member 16 has a hole 22 in its side wall above its
lower end 17. (See FIG. 4.) The clutch spring 20 has a series of
coils and is bent radially inward at one end 24 with its other end
26 being open, or "free". (See FIG. 7.) The coiled clutch spring 20
is located in the annular space 18 with its bent end 24 passing
through the hole 22 in the side wall of the drive member 16. The
open end 26 of the clutch spring 20 rests in the bottom region of
the annular space 18 as seen in FIG. 1.
[0030] Preferably, the annular space 18 is made narrower at its
bottom region near the open end 26 than at its top region near its
bent end 24 (as seen in FIG. 1). To provide this variation in the
annular space 18, an inner wall 13 of the housing 10 is curved on a
smaller radius near the bottom end 11 than at the opposite or top
end. The narrower portion of the annular space 18 serves to confine
the open end 26 against radial movement so that when relative
rotation (e.g. clockwise) between the housing 10 and the drive
member 16 tends to uncoil the clutch spring 20 the clutch spring
will first engage the inner wall 13 with the open end 26 rather
than at some location between the two ends 24 and 26. This assures
that whenever the clutch spring 20 is to be engaged, it will
reliably engage the inner wall 13 throughout the length of the
clutch spring 20, and stop that relative rotation with a minimum of
unpredictable slippage. In this embodiment of the invention,
relative rotation in the opposite direction (e.g. counterclockwise)
lets the open end 26 of the clutch spring slip by the inner wall 13
of the housing without opposing that relative rotation. In other
words, the clutch spring 20 remains in the same coiled position
shown in FIG. 2 while rotating within the annular space 18 if the
wrench is turned counterclockwise. Accordingly, the coiled spring
20 in the annular space 18 thus functions as a stepless,
unidirectional clutch.
[0031] Referring again to FIGS. 1 and 2, and to FIGS. 5a, 5b and
5c, the rotor body 30 is supported within the driver member 16. At
one end, the rotor body 30 has a flanged head 32 which rests on and
in one end of the driver member 16. At its other end 34, the rotor
body 30 has a reduced diameter where the rotor body 30 is supported
coaxially in the driver member 16 by two coaxially interfitting
hubs 36 and 38 which are shown in detail in FIGS. 6a-6b. The first
hub 36 is press-fitted into interlocking engagement with the end of
the driver member 16 that is remote from the flanged head 32 and
overlies the adjacent ends 11 and 17, respectively, of the housing
10 and the driver member 16. The second hub 38 has a central bore
which is press-fitted over the smaller-diameter end 34 of the rotor
body 30. The second hub 38 fits rotatably within the first hub 36
and overlies its end surface 37.
[0032] A torsion spring 40 has a coiled shape with two ends 42 and
44 extending in opposite directions generally parallel to the axis
of rotation of the rotor body 30 as seen best in FIGS. 8a-8c. The
upper end 42 fits in a hole 46 in the underside of the flanged head
32 of the rotor body 30, as shown in FIG. 1, and is anchored to the
rotor body 30. The bottom end 44 engages in a hole 48 in the body
of the first hub 36 and is thereby anchored in the first hub 36
and, through it, to the driver member 16 as seen in FIG. 1. The
ends 42 and 44 of this spring 40 need not be collinear, but can be
relatively displaced around the axis of the housing 10 as shown in
FIG. 8d. If the ends 42 and 44 of the spring 40 are so displaced,
the first hub 36 can be correspondingly displaced around the axis
to locate the hole 48 to accommodate the location of the end 44
which is engaged in that hole 48. The torsion spring 40 is
preferably made of the 303 Series Stainless Steel and has a
diameter of about 0.05 inches (1.25 mm).
[0033] In use, the housing 10, acting through the clutch spring 20,
turns the driver member 16. The driver member 16 and the
interlocked first hub 36, when turned, will turn the rotor body 30
through the torsion spring 40 which connects the hub 36 and the
rotor body 30. When the rotor body 30 encounters resistance to
turning, a force is applied to the torsion spring 40 resulting in
the driver member 16, and with it, the first hub 36 being displaced
rotationally relative to the rotor body 30 and second hub 38. The
magnitude of the displacement angle corresponds to the torque
applied to the torsion spring 40.
[0034] Marks 39A, 39B and 39C are provided on the surfaces 38' and
36' of the driver member 16 and the rotor body 30 to indicate a
precalibrated magnitude of this torque. When the torque magnitude
is zero, the mark 39B on the driver member 16 is adjacent the mark
39A on the rotor body 30. When the rotor body 30 is held against
rotation and the driver member rotates around its common axis the
second mark 39C on the driver member 16 moves toward the mark 39A
on the rotor body 30 and reaches the mark 39A when the
precalibrated torque value is reached. Of course, the invention
contemplates the use of several markings corresponding to various
torque levels. In one embodiment, each wrench is calibrated by the
manufacturer to ensure that the torsion spring 40 will produce the
torque corresponding to the markings 39A, 39B, and 39C.
[0035] Referring again to FIGS. 5a, 5b and 5c, the rotor body 30 is
adapted to hold various tools. A socket 50 is provided in the
smaller end 34 for the reception of a tool. While the socket 50 has
a hexagonal cross-sectional shape, its shape is merely exemplary
since other shapes can be used. A cavity 52 in the opposite end of
the rotor body 30 opens through the head 32 providing for auxiliary
tool holders, examples of which are shown in FIGS. 9 to 15,
inclusive.
[0036] FIG. 9 shows the pertinent part of a tool 56 comprising a
shaft having an "ISO" (International Standards Organization) type
dental tool latch which is in general use in dentistry. The
latching head 58 has an annular groove 60, an axially-oriented flat
surface 62 terminating at a transverse surface 63, which are
characteristic of this type of the latching head 58. The tool
holders shown in FIGS. 10 to 15, inclusive, are designed to engage
tools using the ISO-type latch.
[0037] FIGS. 10-11 illustrate one such tool holder 70, employing a
spring 72 coiled around a tubular body 74 having a top flange 76
which can be press-fitted into the cavity 52 with the tubular body
74 located within the passage 51 leading to the socket 52. The body
74 has a notch 78 and a bevel 80 formed in one side and a partial
shoulder 83 bearing a transverse flat surface 82 on the inner wall
opposite the notch 78 and bevel 80. The spring 72 is coiled around
the body 74 with its first end 84 terminating in a straight segment
resting in the notch 78 and its second end 86 terminating a
straight segment resting adjacent to the bevel 80.
[0038] In use as shown in FIG. 12, the latch head 58 of the tool 56
is moved into the tool holder 70 through the socket 50 and the
passage 51 leading to the cavity 52 with its flat surface 62
oriented to move past the flat surface 82 of the partial shoulder
83 as indicated by the vertical arrow "a" in FIG. 12a. Eventually,
the head 58 encounters the second end 86 of the spring 72 at which
point further movement into the tool holder 70 pushes the coil at
the second end 86 of the spring 70 upward to an approximately
horizontal position as shown in FIG. 12b. At this point, the head
58 can move past that coil into the body 74 as shown in FIG. 12c.
Now the lower coil at the second end 86 rests in the annular groove
60 of the latch head 58. The latch can be moved further into the
body 74 with the flat surface 62 passing by the flat surface 82 of
the partial shoulder 83 as shown in FIG. 12d. Moving the latch
further into the body 74, the head 58 encounters the first end 84
of the spring 72 and pushes it slightly out of the notch 78 as
shown in FIG. 12e. Finally, as is shown in FIG. 12f, the latch head
58 comes to rest firmly latched in the tool holder 70 with the
first end 84 of the spring 72 engaged in the annular groove 60 and
the flat surface 62 of the latch engaged against the flat surface
82 of the partial shoulder 83. Additionally, the transverse surface
63 of the latch head 58 is engaged against the underside of the
partial shoulder 83 and the coil 86 at the second end of the spring
embraces the shaft of the tool 56 beneath the annular groove
60.
[0039] When the tool 56 is installed in the tool holder 70, the
latter being installed in the cavity 52, the shaft passes through
the passage 51 and the socket 50 in the rotor body 30. Thus, all
tools installed in the rotor body 30 will extend in the same
direction from the wrench and the torque-indicator marks 39A, 39B
and 39C will at all times be visible when the wrench is in use.
[0040] Removing the tool 56 from the tool holder 70 is illustrated
in FIGS. 12g to 12j. A pull-out force indicated by an arrow "b" in
FIG. 12g forces the first end 84 of the spring 72 out of the notch
78 and moves the flat surface 62 by the surface 82 of the partial
shoulder 83. The latch is then disengaged from the shoulder 83 and
the annular groove 60 is held by the coil at the second end 86 of
the spring as shown in FIG. 12h. At this point the tool 56 is
turned 180.degree. as is indicated by an arrow "c" in FIG. 12i,
presenting the flat surface 62 to the second end 86 of the spring.
The tool 56 is now free to be removed from the tool holder 70 as
seen in FIG. 12j.
[0041] FIGS. 13a-g, inclusive, show a tool holder similar to the
one shown in FIGS. 10 and 11 employing a spring 72' differing in
form from the spring 72 but performing the same functions. The
spring 72' has straight segments 84' and 86' deployed in the notch
78 and adjacent the bevel 80, respectively, like the straight
spring segments at the ends 84 and 86 in FIGS. 10-11. However,
rather than being at the ends of the coil spring 72, the straight
segments 84' and 86' in FIG. 14 are each part of a D-shaped part 90
or 92, respectively, enveloping the tubular body 74. These D-shaped
parts 90 and 92 are joined together by a bight segment 94.
[0042] Another alternative tool holder 110, shown in FIGS. 14 and
15, comprises a main body 112, a latch body 114, a latch handle
116, a spacer washer 118 and a shim 100. In use, all components
except the latch handle 116 are installed in the cavity 52 in the
rotor body 30. The latch handle 116 overlies the rotor body 30 (not
shown).
[0043] The main body 112 and the spacer washer 118 are press-fitted
into the cavity 52 which is aided by the expanded land region 111
on the main body 112. The latch body 114 and the latch handle 116
are press-fitted together. The latch body 114 has an opening 117
which can be brought into register with a cross passage 119 in the
main body 112 under control of the latch handle 116. The latch body
114 has also a dog 115 opposite the entrance into the opening 117.
The tool 56 is insertable into the tool holder 110 through a
passage 113 in the main body 112 which communicates with the cross
passage 119 to place the latch head 58 in an opening 102 in the
latch handle 116.
[0044] As is shown in FIG. 14a, the main body 112 has a partial
shoulder 104 extending into the passage 113 which engages the flat
side 62 of the tool 56 and thereby guides the tool 56 to be
inserted with a prescribed orientation around its longitudinal axis
to allow the latch head 58 to enter the opening 102 in the latch
handle 116. After the tool 56 is correctly inserted into the tool
holder 110, the latch handle 116 is rotated approximately
180.degree. to place the dog 115 in the groove 60 of the tool and
thereby lock the tool 56 in place in the tool holder 110, as is
illustrated in FIG. 14b. A flat surface 120 across the latch handle
116 is useful to turn the latch handle 116 and to indicate the
locked position.
[0045] The torque indicator wrench that is described herein is a
one-way wrench, useful to apply torque to a screw or a bolt in one
direction but not the opposite direction. It is intended for use to
tighten a screw to a prescribed torque, as is desired in implant
dentistry, by allowing the clinician to visualize the relative
position of the marking 39A to the other torque markings 39B and
39C. Moreover, a ratchet wrench of the present invention can be
made quite small. The housing 10 may have a diameter of about 0.75
inch or less and the height of housing 10, with the hubs and rotor
body attached, is about 0.5 inch or less.
[0046] Because there is typically no need to be concerned with
torque levels when removing a screw, the dental practitioner can
use an ordinary tool for that task. Thus, the torque-indicator
wrench of the present invention can be designed for the one task
where it is needed, thereby providing the needed wrench at minimum
cost to the practitioner. However, a bi-directional wrench can be
provided by adding a similar tool socket, like the socket 50, at
both ends of the passage 51 in the rotor body 30. For that purpose,
torque-indicator marks would be useful on both axial ends of the
wrench. The clinician desiring to reduce the torque on a screw to a
known amount could do so by turning the wrench over and using the
opposing socket.
[0047] FIGS. 16-17 illustrates an alternative torque indicator
ratchet wrench similar to the one described above, but which
includes a washer 130 between the first hub 36 and the second hub
38 to provide smoother movement to the wrench. The washer 130 is
preferably made of a lubricious material to reduce the friction
between the first and second hubs 36, 38. Further, the material
should be able to withstand the environment of an autoclave and
also be relatively rigid so as avoid distortion when operational
forces are applied thereto. One example of a material that provides
these desired qualities is Teflon.RTM.. An example of a metallic
material is a metal with a gold coating where the gold coating acts
as a lubricant.
[0048] By reducing the friction between the first and second hubs
36, 38, the washer 130 provides a smoother feel during ratcheting.
While not affecting the accuracy of the torque indicating feature,
the washer 130 enhances the ability of the marking 39A on the rotor
body 30 to return to the zero-torque marking 39B on the drive
member 16. As mentioned above, each wrench is individually
calibrated to ensure the markings 39A, 39B, and 39C are properly
placed. Thus, these markings 39A, 39B, 39C are typically placed on
the wrench after it has been fully assembled and calibrated.
However, the washer 130 provides much more uniformity from the
wrench to wrench such that, when the torsion springs 40 are uniform
in their spring force, it has become relatively feasible to provide
the markings before final assembly.
[0049] Further, to reduce the other frictional forces present in
the wrench, a washer like washer 130 may be placed the rotor body
30 and the driver member 16. Further, a cylindrical
friction-reducing member (e.g. a Teflon.RTM. cylinder) may be
placed on the walls of the driver member 16 to reduce the
frictional engagement with the spring 40. This further enhances
uniformity for wrench to wrench.
[0050] FIG. 18 shows a latching tool holder 140 that is similar to
the tool holder in FIGS. 13a-13g. The tool holder 140 includes a
top flange 142 and a tubular body 144. The holder 140 is press fit
into cavity of the wrench as shown in FIG. 16 and generally
described above with reference to FIGS. 10-13. The spring 146 has a
lower tool-engaging portion 148 and an upper tool-engaging portion
150. The upper tool-engaging portion 148 is placed within a
cylindrical roller 152 that is resident within a notch 154 in the
tubular body 144, unlike the previous configurations where the
tool-engaging portion of the spring directly engages the notch.
[0051] The cylindrical roller 152 has a diameter that is small
enough to protrude past the inner wall of the tubular body 144 such
that it will encounter the annular groove 60 on the head 58 of the
tool (as shown in FIG. 9 by itself, and FIG. 12 in operation). The
cylindrical roller 152 preferably has a diameter that is at least
slightly larger than the axial dimension of the annular groove 60
and protrudes past the inner wall of the tubular body 144 by a
small amount, usually less than 0.025 inch. The top flange 142 may
also include a relief cut-out 156 to allow the cylindrical roller
152 to seat properly within the notch 154.
[0052] Unlike the configuration of FIGS. 12 and 13 where the
movement of the tool-engaging portion of the spring into and out of
the annular groove 60 may be difficult due to the head 58 above the
groove 58 and the shoulder below the groove 58, the cylindrical
roller 152 smoothly rolls into and out of the groove 60.
Accordingly, the clinician is much less likely to encounter any
problems during the insertion or removal of the tool from the tool
holder 140.
[0053] In another variation to the cylindrical detent ISO-latch
mechanism of FIG. 18, the tool holder 140 can lack the notch 154
and the spring 146. Instead, the lower end of the tool holder 140
opposite the top flange 142 has a plurality of resilient fingers
that project slightly inwardly into the cylindrical cavity formed
by the tool holder 140. The tool, when inserted into the tool
holder 140, forces the resilient fingers radially outward and is
snugly held by the fingers. The tool is then rotated as in the
previous embodiments so at to have its flat surface engage the
corresponding flat surface on the shoulder within the tool holder
140. Utilizing the resilient fingers has the benefit of retaining
the tool at nearly every position during the insertion and removal
processes. Further, it is less costly since it does not need the
spring or special machining cuts in the cylindrical surface of the
tool holder. Also, it is possible to make this type of tool holder
by having a separate part containing the resilient fingers
press-fitted into the opening at the lower end of the tool holder.
Additionally, the internal shoulder having the flat that engages
the flat of the tool could be formed by inserting another separate
part having the D-shaped interior into the opening at the flange
end of the tool holder.
[0054] While the present invention has been described with
reference to one or more preferred embodiments, those skilled in
the art will recognize that many changes may be made thereto
without departing from the spirit and scope of the present
invention which is set forth in the following claims.
* * * * *