U.S. patent application number 12/157331 was filed with the patent office on 2009-01-29 for orthodontic force module.
Invention is credited to Stephen D. Hanks.
Application Number | 20090029309 12/157331 |
Document ID | / |
Family ID | 38749944 |
Filed Date | 2009-01-29 |
United States Patent
Application |
20090029309 |
Kind Code |
A1 |
Hanks; Stephen D. |
January 29, 2009 |
Orthodontic force module
Abstract
An orthodontic force mechanism includes a jack screw having a
pair of ends, at least one of which is threaded, and a central
spindle between the ends, which spindle has two intersecting radial
through-holes therein. A pair of nut housings are mounted on the
end portions of the jack screw, at least one of which is threadedly
coupled to a threaded end portion of the jack screw. A lock
mechanism mounted on the central spindle section includes a
spring-loaded detent configured to engage an end opening of each of
the through holes in the spindle when the through hole is in
alignment with the detent, such that the spindle cannot rotate
relative to the lock mechanism when the detent is inserted into a
through hole. The detent can be moved out of engagement with a
through hole using a tool inserted into that through hole from its
opposite end.
Inventors: |
Hanks; Stephen D.; (Las
Vegas, NV) |
Correspondence
Address: |
Philip G. Meyers;Philip G. Meyers Law Office
Suite 300, 1009 Long Prairie Road
Flower Mound
TX
75022
US
|
Family ID: |
38749944 |
Appl. No.: |
12/157331 |
Filed: |
June 9, 2008 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11440869 |
May 25, 2006 |
7384265 |
|
|
12157331 |
|
|
|
|
Current U.S.
Class: |
433/7 |
Current CPC
Class: |
A61C 7/10 20130101 |
Class at
Publication: |
433/7 |
International
Class: |
A61C 7/10 20060101
A61C007/10 |
Claims
1. An orthodontic force mechanism, comprising: an elongated jack
screw having at a pair of end portions, at least one of which is
threaded, and a central spindle section between the end portions,
which spindle section has at least two radial holes therein; a pair
of nut housings mounted on the end portions of the jack screw, at
least one of which is threadedly coupled to a threaded end portion
of the jack screw; and a lock mechanism mounted on the central
spindle section, which lock mechanism includes a spring-loaded
detent configured to engage an end opening of each of the radial
holes in the spindle section when such hole is in alignment with
the detent, such that the spindle cannot rotate relative to the
lock mechanism when the detent is inserted into a hole, and is free
to rotate relative to the lock mechanism when the detent is clear
of a hole, wherein the detent can be moved out of engagement with a
hole using a tool inserted into that hole from its opposite end
such that a distal end of the tool pushes the detent out of the
hole.
2. The orthodontic force mechanism of claim 1, further comprising a
mechanism connecting the lock mechanism to the nut housings in a
manner effective to prevent the locking mechanism from moving with
the spindle section during rotation of the jack screw with a
tool.
3. The orthodontic force mechanism of claim 1, wherein the end
portions of the jack screw are threaded in opposite directions, and
the nut housings are threadedly coupled to the end portions of the
jack screw.
4. The orthodontic force mechanism of claim 1, wherein the lock
mechanism comprises a housing having an outwardly opening recess
and a bearing surface in engagement with the jack screw, wherein
the spring is disposed in the recess and confined for compression
between the detent and the housing.
5. The orthodontic force mechanism of claim 3, wherein the lock
mechanism comprises a housing having an outwardly opening recess
and a bearing surface in engagement with the jack screw, and the
spring is disposed in the recess and confined for compression
between the detent and the housing, and the mechanism further
comprises a guide rod slidably disposed in guide openings in each
of the nut housings, wherein the housing of the lock mechanism is
secured to the guide rod such that the lock mechanism does not
rotate relative to the jack screw when the jack screw is rotated in
a manner effective to cause the nut housings to move toward or away
from one another.
6. The orthodontic force mechanism of claim 1, wherein the radial
holes comprise a pair of through holes that intersect at a
lengthwise axis of the jackscrew.
7. The orthodontic force mechanism of claim 6, wherein the spindle
section has two of the through-holes therein, which through-holes
perpendicular to each other.
8. The orthodontic force mechanism of claim 1, wherein the detent
comprises a cup having a rounded outer end surface on that engages
end openings of the radial holes, and an inner recess into which
the spring extends.
9. The orthodontic force mechanism of claim 8, wherein the outer
end openings of the radial holes are flared and rounded to form
lock seats with a curvature that complements the curvature of the
rounded outer end surface of the detent.
10. The orthodontic force mechanism of claim 1, further comprising
a pair of attachment rods extending from each of the nut housings,
which attachment rods are configured for attachment to an
orthodontic appliance to be installed in the mouth of a
patient.
11. An orthodontic force mechanism, comprising: an elongated jack
screw having a pair of end portions threaded in opposite directions
and a central spindle section between the end portions, which
spindle section has at least two intersecting radial through-holes
therein; a pair of nut housings threadedly coupled to the end
portions of the jack screw; a pair of attachment rods extending
from each of the nut housings, which attachment rods are configured
for attachment to an orthodontic appliance to be installed in the
mouth of a patient; a lock mechanism mounted on the central spindle
section, which lock mechanism includes a spring-loaded detent
configured to engage an end opening of each of the through holes in
the spindle section when such through hole is in alignment with the
detent, such that the spindle cannot rotate relative to the lock
mechanism when the detent is inserted into a through-hole, and is
free to rotate relative to the lock mechanism when the detent is
clear of a through hole, wherein the detent can be moved out of
engagement with a through hole using a tool inserted into that
through hole from its opposite end such that a distal end of the
tool pushes the detent out of the through-hole; and a guide rod
slidably disposed in guide openings in each of the nut housings,
wherein the lock mechanism is secured to the guide rod such that
the lock mechanism does not rotate relative to the jack screw when
the jack screw is rotated in a manner effective to cause the nut
housings to move toward or away from one another.
12. A lighted wrench for use in tightening an orthodontic force
module, comprising: a hollow handle; a battery disposed in the
handle; a head connected to the handle by a pivot; an LED mounted
on the head and connected to the battery by electrical connections;
a tool mounted on the head proximate the LED and extending
forwardly therefrom, the having a reduced diameter tip configured
to fit inside a hole in a jack screw forming part of an orthodontic
force module.
Description
[0001] This application is a divisional of U.S. Ser. No.
11/440,869, filed May 25, 2006.
FIELD OF THE INVENTION
[0002] The present invention generally relates to orthodontics and,
more particularly, to an orthodontic force modules of the type used
for palatal expansion and other applications.
BACKGROUND OF THE INVENTION
[0003] Orthodontic palatal expansion is commonly carried out using
a force module that is installed on the upper dental arch of a
patient's mouth, the force module being connected to a palatal
expander of a type commonly known in the art. The method of palatal
expansion using expansion screws has become known in the art as
"rapid palatal expansion" (RPE). Force modules used for this
purpose must be tightened periodically to be effective.
[0004] Huge et al. U.S. Pat. No. 6,783,361, Aug. 31, 2004,
describes an orthodontic mechanical force module having a jack
screw whose rotation is controlled by a ratchet. In one embodiment,
a pair of housings are interconnected with the patient in any
appropriate manner, and are further rotatably interconnected with a
rotatable spindle. At least one of these housings is also
threadedly engaged with the spindle. A ratchet is associated with
the spindle to selectively allow the spindle to rotate only in a
direction that increases a magnitude of the treatment forces being
exerted on the patient by changing the spacing between the pair of
housings by a movement of at least one of the housings along the
spindle due to its rotation. In an active position, the ratchet
precludes the spindle from rotating in a direction that would tend
to reduce the magnitude of the treatment forces being exerted on
the patient.
[0005] The Huge et al. device, and also an appliance described in
literature as the "RatchetRax" claim to provide bi-directional
adjustment capability. The device of the present invention
incorporates a mechanical locking device, unlike those of the
previously mentioned devices, that allows bi-directional activation
of the screw mechanism without a multitude of tools or augmented
instruction to the user. The RatchetRax is bi-directional, but
moves only one nut body to create the expansion. The great
disadvantage inherent with movement of one nut body as opposed to
both nut bodies is that the overall lateral size of the single body
movement device must necessarily be twice as wide to effect the
same amount of expansion or contraction. Appliance size is critical
relative to accommodation in the mouth and to patient comfort and
tolerance.
[0006] Bi-directional adjustability allows the mechanism to be
employed not only as an expansion device (activation of the nut
bodies apart from each other) but also as a contraction device
wherein the bodies are purposefully installed in the patient
screwed apart and then activated to bring them together, thereby
delivering a closing force as opposed to an expanding or opening
force. This is a common application of such force modules, i.e. to
move teeth adjacent to an edentulous space together to eliminate
the space and mitigate the need for a prosthesis. The most common
applications of such force modules are expansion of the palate,
expansion of the mandibular alveolus, contraction of teeth adjacent
to an edentulous site, and contraction of the palate.
[0007] Screw de-activation (screw reverses direction after
activation) has always been a challenge with expansion screws. In
order to control screw reversal, most prior art mechanisms have
incorporated some type of screw thread drag adjunct (lacquer
coating, nylon bushing, etc.). These have sometimes been
successful, but many times not. A popular device described in U.S.
Pat. No. 6,482,001 suffered problems with screw reversal that could
not be controlled. When an expansion device fails, its removal and
replacement subjects the patient to the rigors of duplicating
previous protocols. Additionally, after such expansion has begun
and then fails, appliance removal is considerably more
uncomfortable because the involved tissues are in a heightened
state of irritability. Furthermore, clinicians experience
aggravation over lost time, duplication of effort, and poor public
relations that invariably result from patients and/or parents of
patients exasperated about the inconvenience of repeated
appointments and delayed treatment time. Locking the screw in place
mechanically is the surest way to prevent screw reversal. The
present invention inhibits screw reversal without requiring
additional tooling and instruction.
SUMMARY OF THE INVENTION
[0008] An orthodontic force mechanism according to the invention
includes an elongated jack screw having at a pair of end portions,
at least one of which is threaded, and a central spindle section
between the end portions, which spindle section has at least two
radial holes therein. A pair of nut housings are mounted on the end
portions of the jack screw, at least one of which is threadedly
coupled to a threaded end portion of the jack screw. A lock
mechanism is mounted on the central spindle section, which lock
mechanism includes a spring-loaded detent configured to engage an
end opening of each of the radial holes in the spindle section when
such hole is in alignment with the detent, such that the spindle
cannot rotate relative to the lock mechanism when the detent is
inserted into a radial hole, and is free to rotate relative to the
lock mechanism when the detent is clear of a radial hole. In a
preferred embodiment, the radial holes comprise intersecting
through holes. The detent can be moved out of engagement with a
through hole using a tool inserted into that through hole from its
opposite end, such that a distal end of the tool pushes the detent
out of the through-hole, and the same tool can then be used to
rotate the jack screw. For the reasons noted above, it is preferred
that both end portions of the jack screw are threaded in opposite
directions, with the nut housings are threadedly coupled to the end
portions of the jack screw.
[0009] In a preferred embodiment, the lock mechanism according to
the invention comprises a housing having an outwardly opening
recess and a bearing surface in engagement with the jack screw. The
spring is disposed in the recess and confined for compression
between the detent and the housing. A guide rod is slidably
disposed in guide openings in each of the nut housings, and the
housing of the lock mechanism is secured to the guide rod such that
the lock mechanism does not rotate relative to the jack screw when
the jack screw is rotated in a manner effective to cause the nut
housings to move toward or away from one another. For this purpose,
the housing of the lock mechanism can be slidably supported on the
guide rod, or the guide rod can be made integral with the housing,
e.g. as projections extending in opposite directions. A pair of
attachment rods extend from each of the nut housings, which
attachment rods are configured for attachment to an orthodontic
appliance to be installed in the mouth of a patient.
[0010] In an especially preferred embodiment, the openings of each
through hole in the spindle section are configured to receive a
coil-spring activated detent element oriented perpendicularly to
the long axis of the jack screw either within the confines of a
lock housing, thereby "locking" and "unlocking" according to
compression or expansion of the encapsulated coil spring. The
detent element/lock housing interface with lock-seats of the
spindle section inhibit the spindle from spontaneously rotating in
a direction that would decrease the magnitude of desired force, but
that, in fact, will readily without adjunct tooling or instruction
allow reverse rotation of the spindle according to the need and
desire of the prescribing clinician. A force module such as
described in Huge et al. provided with a tempered leaf spring
locking mechanism is prone to breakage as a result of binding with
the plurality of activating tools. In the "RatchetRax" device, if
after partial activation and bowing of the leaf spring, the
direction is reversed against the "bow" of the spring, a binding
force can occur thereby causing the leaf spring to break. A sliding
ball or cup locking arrangement of the present invention is
activated by a coil spring as opposed to a leaf spring, which coil
spring is protected from all outside destructive influences by
virtue of its encapsulation within the confines of the lock housing
thereby rendering it more protected and hence less sensitive to
mechanical breakage. Furthermore, the nature of a coil spring as it
functions through a cycle of expansion and contraction is not
stressed and therefore not prone to break like a "bowed" leaf
spring is if in mid-cycle the direction of stress is reversed.
[0011] The invention further provides a lighted wrench for use in
tightening an orthodontic force module. Such a wrench includes a
hollow handle, a battery disposed in the handle, a head connected
to the handle by a pivot, an LED mounted on the head and connected
to the battery by electrical connections such as wires, and a tool
mounted on the head proximate the LED and extending forwardly
therefrom. The tool has a reduced diameter tip configured to fit
inside a hole in a jack screw forming part of an orthodontic force
module. These and other aspects of the invention are discussed
further in the detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWING
[0012] In the accompanying drawing, wherein like numerals represent
like elements:
[0013] FIG. 1 is a perspective view of a force module according to
the invention, with nut housings detached;
[0014] FIG. 2 is a perspective view of the force module of FIG. 1,
with the nut housings threaded on;
[0015] FIG. 3 is an exploded perspective view of the force module
of FIG. 1;
[0016] FIG. 4 is a perspective view of an alternate form of detent
element according to the invention;
[0017] FIGS. 5A, 5B and 5C are a series of lengthwise sectional
views showing use of a tool according to the invention to unlock
the lock mechanism and rotate the jack screw; and
[0018] FIG. 6 is a side view of a lighted tool according to the
invention.
DETAILED DESCRIPTION
[0019] The force module according to the invention has two main
applications. In a first application, the nut housings are as
proximate as possible and the desired result is to create a wider
separation of anatomical entities, e.g., rapid palatal expansion.
The main body of the device in its closed state is centered over
the midline of a patient's palate with a clearance of some few
millimeters with the lateral rods connected at their distal ends
either by welding, brazing, or some other mechanical interface to
the lingual surface of "bands" (braces) on a single tooth or
multiple teeth on each side of the jaw. The end result of the
expansion protocol is to open the suture joint which runs in the
midline of the palate thereby separating one side from the other
thus creating a greater inter-dimensional width between the teeth
supporting the device. Activation is achieved by progressively
rotating the jack screw in a direction to cause the device body or
bodies to move apart from each other. Such activation is
accomplished using a tool which inserts into holes in the center
unthreaded portion of the jack screw spindle. Frequency of
activation is monitored and controlled under the auspice of a
qualified and licensed health care provider. Such activation
continues according to a prescribed schedule until the desired
expansion has been accomplished.
[0020] In the second application, the device is adjusted so that
nut bodies are maximally separated prior to fabrication of the
patient assembly before insertion into the mouth. The desired end
result in this application could be the closing of space created by
a missing tooth, or as an adjunct to resolve a "Brody Bite". The
device would be activated so that the opposing nut bodies would
come together. For instance, the lateral rods would be attached at
their distal ends to each of the teeth adjacent to an edentulous
site. The treatment goal is to deliver the necessary force required
to move the teeth toward each other until they are in contact
thereby eliminating the space and mitigating the need for a
prosthesis to replace the missing dental unit. In a Brody Bite
treatment, the device would be applied to effect a result just
opposite that described in the first application above. In both
applications as noted above, the device would function in one of or
multiples of the hereinafter described mechanisms all designed to
inhibit screw reversal.
[0021] Referring to FIGS. 1-4, a force module 10 according to the
invention includes a jack screw 11, a pair of nut housings or
bodies 12, a lock mechanism 13 supported on a guide rod 14, and a
pair of attachment rods 16 which may be welded or otherwise secured
to nut housings 12 for connecting force module 10 to other
orthodontic components that engage the anatomy, such as for the
purposes discussed above. Jack screw 11 has a pair of threaded end
portions 17 separated by a central spindle section 18. End portions
17 are essentially identical (Class 3a 2-56 UNC) except that they
are threaded in opposite directions so that rotation of jack screw
11 moves nut housings either closer together or further apart along
the length of jack screw 11. In a preferred embodiment, jack screw
11 is approximately 0.60'' to 0.80'' long depending on the
application.
[0022] Each nut housing 12 has a threaded through-hole 19 into
which one of threaded end portions 17 is coupled. Nut housings 12
are, for example, identically threaded Class 3a 2-56 UNC, except
that one has a right hand internal thread and the other has a left
hand internal thread. One end portion 17 of jack screw 11
terminates in a notch 21 that allow jack screw to be screwed or
unscrewed with a screwdriver.
[0023] FIG. 2 illustrates force module 10 with nut housings 12
brought close together by repetitive tightening of jack screw 11 as
described hereafter. It is possible according to the invention that
only one end portion 17 be threaded, and in such a case the other
end portion will be welded or otherwise fixed to the other nut
housing. This is, however, not preferred because a one-sided jack
screw renders the force module not as compact as one capable of
extending the same distance using a double-sided jack screw.
[0024] Spindle section 18 of jack screw 11 is unthreaded and is of
greater diameter than the threaded end portions 17. Spindle section
18 has two 90.degree. opposed, intersecting through holes 22
therethrough that receive the activation tool thereby facilitating
rotation of the jack screw 11. Although there are four activation
hole openings in the example shown, only one hole at a time lends
itself to activation of the jack screw. That hole is 180.degree.
opposed to the hole that is locked in position by the lock
mechanism 13.
[0025] Referring to FIG. 3, lock mechanism 13 comprises a lock
housing 26 having two pairs of arms or tines 27 that define a pair
of spaced, laterally opening, rounded U-shaped grooves 28 that
match the curvature of jack screw 11. When mounted on jack screw
11, arms 27 engage a pair of annular shoulders 29 on opposite sides
of central spindle section 18. Jack screw 11 is thereby rotatably
mounted in grooves 28. Lock housing 13 further has a central hollow
portion or recess 31 that opens in the same direction as grooves
28. A compression coil spring 32 is disposed in recess 31 with its
inner end engaging the bottom of recess 31. A detent or lock
element 33 takes the form of a rearwardly-opening cup with a
rearwardly facing recess 34 and a rounded outer end 36. Spring 32
fits inside recess 31 and biases detent 33 towards a projecting
position. The hollow portion of recess 31 thus encapsulates the
mesial end of coil spring 32, which exerts a constant expansive
pressure. The cup-shaped lock element 33 can fit entirely within
the larger diameter recess 31 of lock housing 26, free to slide
parallel to the long axis of housing 26 to thereby accomplish the
locking/unlocking function.
[0026] Housing 26 further has a transverse through hole 36 that
guide rod 14 slides into. The form of lock housing 26 is such that
it is stabilized in place relative to the spindle of jack screw 11.
To hold lock mechanism 13 so that it does not rotate when jack
screw 11 is rotated, lock housing 26 is centered on guide rod 14,
and the ends of guide rod 14 are retained in a pair of opposed
holes 37 in nut housings 12. Holes 37 are spaced from and extend in
parallel to the threaded through-holes 19. Guide rod 14 passes
through hole 36 in housing 26 and may be welded or integrally
formed with housing 26 so that the ends of the guide rod 14 remains
equidistant from housing 11 during travel of the nut bodies 12.
Guide rod 14 passes through holes 37 in nut bodies 12, which move
freely along rod 14 as nut bodies 12 are moved apart or together.
The primary purpose of rod 14 is to support the distal end of lock
housing 26. Arms 27 and guide rod 14 maintain the housing 26
stationary relative to the jack screw 11 so that the lock element
33 is prohibited from leaving its centered position over the
through holes 22 that would otherwise occur as the housing 11 would
be influenced by the turning spindle to follow the direction of
rotation.
[0027] FIGS. 5A-5C illustrate lock mechanism 13 in operation. As
shown in FIG. 5A, end portions of each through hole 22 are flared
to form lock seats 38 in the form of countersunk holes that match
the curvature of rounded end 36 of detent 33. Preferably, as shown
in FIG. 4, detent 33 has a cylindrical tip 39 that fits loosely
into hole 22 just behind lock seat 38 to provide a more secure
locking action. When detent 33 is in alignment with a hole 22 in
spindle section 18, spring 32 biases it into contact with lock seat
38 as shown, locking spindle section 18 from rotation. A wrench or
similar tool 41 is inserted into the hole 22 that detent 33 has
engaged, but from the opposite end as shown. Tool 41 contacts the
tip of rounded end 36 and pushes it back, compressing spring 32.
The user then rotates jack screw 11 using tool 41 by an angle equal
to the angular spacing of holes 22, in this example 90 degrees. As
the user moves tool 41 and jack screw 11 through the angle, rounded
end 36 engages and slides along a rounded circumferential groove 42
in spindle section 18 (FIG. 5C) that serves as a race for the
locking element. If a locking element as shown in FIG. 4 is used,
groove 42 has an annular, central bottom channel matching the
profile of tip 39 for tip 39 to slide in.
[0028] When detent 33 is brought into alignment with the next hole
22, it engages its seat 38 and assumes a position like that shown
in FIG. 5A. Tool 41 is then withdrawn and reinserted into the next
hole 22 if further tightening (or loosening) of force module 10 is
desired. During these steps, nut housings 12 move further apart or
closer together depending on the direction of rotation of the jack
screw. In the case of palatal expansion, nut housings 12 are
periodically moved further apart so that attachment rods 16 apply
additional force to the portions of the device that engage the
teeth. Rods 16 may be permanently or removably installed in a third
set of holes 42 in nut housings 12.
[0029] As tool 41 rotates with the spindle section 18, contact with
the lock element 33 is lost. As lock element 33 transitions away
from the end of the tool 41, it rotates into contact with and is
supported by the spindle race, groove 42. When the spindle
completes a 90 degree arc, the lock element 33 eventually loses
contact with the race 42 and falls into the next spindle lock seat
38, thus forming the next lock. Therefore, in this embodiment, a
lock cycle will always amount to one 90 degree turn of the spindle
18.
[0030] Tool 41 in the preceding embodiment is a 0.080'' diameter
wire the end of which has been reduced in diameter, e.g., to
0.035''. The end section extends approximately 0.1'' from the end
of a 0.040'' radius transition of the 0.080'' diameter section to
the 0.035'' diameter section. Total length is about 2 inches, with
the distal end formed to mate with a handle to facilitate
manipulation and make large enough that it cannot be dropped down
the patient's throat. The radiused shoulder 42 of tool 41 is
configured to act as a stop as it engages the rounded lock seat 38,
ensuring that its narrow tip 43 is inserted to the proper depth as
shown in FIGS. 5A-5C.
[0031] A number of variations of the arrangement shown in FIGS. 1-5
are possible. Although a pair of intersecting holes 22 is shown, it
is possible to use a plurality of blind radial holes instead and
rely on tool 41 to cause the lock element to unseat by force,
rather than by engaging it directly, as would be possible with the
lock element lacking tip 39 as shown in FIGS. 1-3. In the event
holes 22 are relatively shallow such that tool 41 as described
above could not be used, the spindle section could be provided with
flats, such as by giving it an octagonal shape in cross section.
The wrench would then be configured to engage these flats. The use
of a guide rod 14 is preferred, but it is possible to make the lock
housing integral with, or rigidly connected to, one of the nut
bodies 12 instead. As a result, only one nut body would be movable
and the device would suffer the same disadvantages as known
one-sided jack screw devices.
[0032] Force module 10 of the invention is commonly mounted near
the roof of the mouth, a dark and difficult to access location.
Holes 22 are small and difficult to see. For that reason, an
improved tool 50 according to the invention includes the tool 41
having a rod-shaped end that fits into holes 22, and a much larger
lighted handle behind it. In the embodiment shown in FIG. 6, a
proximate end of tool 41 is mounted on one side of a head 52 of
tool 50. A light emitting diode 53 is mounted at the front of head
52. Head 52 is connected to a handle 51 by a pivot 54 that allows
the user to reposition head 52 and tool 41 as needed. Handle 51 is
longer and several times wider than the corresponding handle
portion of tool 41 as discussed above. Pivot 54 may be of the type
requiring considerable force to shift between incremental
positions, allowing tool 51 to remain stable during use with head
52 in the desired position. LED 53 is powered by a battery 56
inside handle 51 and connected thereto by wires 57. A lanyard
eyelet 58 or similar attachment device may be provided at the end
of handle 51 opposite head 52. Tool 41 is typically made from
stainless steel or the like, but handle 51, head 52 and pivot joint
54 could be made from molded plastic parts. Eyelet 58 may connect
directly to an end cap that unscrews to allow changing of battery
56 when needed.
[0033] In the straight configuration shown in FIG. 6, the tool of
"light wrench" 50 is advanced toward the through-hole 22 of the
spindle. In situ near the roof of the mouth, the opening of
through-hole 22 points straight toward the front of the mouth, so
as the wrench 50 is advanced toward the hole 22, the light from LED
53 illuminates the darkness of the mouth and the hole, thus
facilitating insertion of the wrench end into the hole. In this
configuration, the user is able to press the wrench 41 against the
lock element 33, thereby pushing it out of and away from its seat
in the lock seat 38 of the spindle.
[0034] Pivot 54 preferably permits head 52 to swing up to 90
degrees in either direction from the position shown. This swiveling
is necessary to allow an appropriate 90.degree. rotation of the
spindle. If there were no swivel, the entire light/wrench assembly
would need to rotate 90.degree., which would be impossible since
the light/wrench overall length would exceed the distance the
patient would be able to open the mouth to allow such rotation.
After the lock element has been displaced, the user applies a
motion which, while holding pressure against the lock element,
causes the light/wrench to "gable" at the joint, thus beginning the
rotation of the spindle until complete at 90.degree.. The present
invention contemplates a method of using the tool 50 according to
the invention as described above, either with the bi-directional
force module of the invention or with other compatible force
modules.
[0035] While certain embodiments of the invention have been
illustrated for the purposes of this disclosure, numerous changes
in the method and apparatus of the invention presented herein may
be made by those skilled in the art, such changes being embodied
within the scope and spirit of the present invention as defined in
the appended claims.
* * * * *