BACKGROUND OF INVENTION
1. FIELD OF INVENTION
[0001] The present invention relates to a wrench equipped with a torque-setting mechanism
and, more particularly, to a wrench equipped with a lockable torque-setting mechanism.
2. RELATED PRIOR ART
[0002] Wrenches are used to exert torque on fasteners such as threaded bolts and nuts to
fasten work-pieces. It is important to exert a proper value of torque. In some applications,
it is particularly important to have the value of torque close to but under a limit
to effectively fasten the work-pieces without the risks of damaging the work-pieces.
[0003] Some wrenches are equipped with torque-setting mechanisms. Such a torque-setting
mechanism is used to set a maximum value of torque that can be exerted via such a
wrench. A typical torque-setting mechanism includes a knob connected to a handle of
a wrench. The maximum value of torque is set by rotating the knob relative to the
handle. The knob might however be accidentally rotated relative to the handle in operation.
[0004] In another conventional torque-setting mechanism, the knob is formed with teeth for
engagement with teeth formed on the handle. The knob can be translated relative to
the handle between two positions. In the first position, the teeth of the knob are
engaged with the teeth of the handle so that the knob cannot be rotated relative to
the handle. In the second position, the teeth of the knob are disengaged from the
teeth of the handle so that the knob can be rotated relative to the handle. The knob
might however be excessively translated and hence removed from the handle.
[0005] In another conventional torque-setting mechanism, a spring-biased detent is connected
to the knob and a recess is made in the handle. The spring-biased detent is intended
for insertion in the recess to keep the knob connected to the handle. The insertion
of the spring-biased detent in the recess has however been proven to be ineffective
to keep the knob connected to the handle.
[0006] In another conventional torque-setting mechanism as disclosed in Taiwanese Patent
M371616 issued to the present applicant, the handle is made with an adequate length
to keep the knob connected to the handle should the spring-biased detent be removed
out of the recess again. The long handle is however unreliable.
[0007] Therefore, the present invention is intended to obviate or at least alleviate the
problems encountered in prior art.
SUMMARY OF INVENTION
[0008] It is the primary objective of the present invention to provide a wrench with a reliable
lockable torque-setting mechanism.
[0009] To achieve the foregoing objective, the lockable torque-setting mechanism includes
a locking mechanism. The locking mechanism includes a sleeve, a body, a pawl and a
lever. The sleeve is non-movably connected to a grip of the wrench and formed with
teeth. The body is non-movably connected to a knob, partially inserted in the sleeve,
and includes a recess in communication with a cavity. The pawl is movably inserted
in the recess and formed with teeth. The lever includes an end for pressing the pawl
and another end pivotally connected to the body. The lever is movable in the cavity
of the body between a first position to press a first portion of the pawl to engage
the teeth of the pawl with the teeth of the sleeve and a second position to press
a second portion of the pawl to disengage the teeth of the pawl from the teeth of
the sleeve.
[0010] Other objectives, advantages and features of the present invention will be apparent
from the following description referring to the attached drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0011] The present invention will be described via detailed illustration of two embodiments
referring to the drawings wherein:
FIG. 1 is a perspective view of a wrench equipped with a lockable torque-setting mechanism
according to the first embodiment of the present invention;
FIG. 2 is a cross-sectional view of the wrench shown in FIG. 1;
FIG. 3 is an enlarged partial view of the wrench shown in FIG. 2;
FIG. 4 is an exploded view of the wrench shown in FIG. 3;
FIG. 5 is an enlarged view of a sleeve used in the wrench shown in FIG. 2;
FIG. 6 is an enlarged view of a body used in the wrench shown in FIG. 2;
FIG. 7 is a side view of the body shown in FIG. 6;
FIG. 8 is an enlarged view of a knob used in the wrench shown in FIG. 2;
FIG. 9 is an enlarged perspective view of a scale ring used in the wrench shown in
FIG 2;
FIG. 10 is a side view of a combination of a switch with the sleeve shown in FIG.
5 and the body shown in FIGS. 6 and 7;
FIG. 11 is a cross-sectional view of the combination illustrated in FIG 10;
FIG. 12 is a side view of the combination in another position than shown in FIG. 10;
FIG. 13 is a cross-sectional view of the combination illustrated in FIG. 12;
FIG. 14 is a cross-sectional view of a lockable torque-setting mechanism according
to the second embodiment of the present invention;
FIG. 15 is a cross-sectional view of the lockable torque-setting mechanism in another
position than shown in FIG. 14; and
FIG. 16 is another cross-sectional view of the lockable torque-setting mechanism shown
in FIG. 15.
DETAILED DESCRIPTION OF EMBODIMENTS
[0012] Referring to FIGS. 1 through 13, there is a wrench 100 according to a first embodiment
of the present invention. The wrench 100 includes a head 10, a grip 40, a torque-relaying
mechanism 102 for delivering torque to the head 10 from the grip 40, a torque-setting
mechanism 101 operable for setting a maximum value of torque deliverable via the torque-relaying
mechanism 102, and a locking mechanism (not numbered) operable for locking the torque-setting
mechanism 101. The head 10 is operatively connected to an insert 11 via a ratchet
mechanism that is not shown for being conventional.
[0013] The grip 40 is a tubular element with two windows 42 and 49 made in the periphery.
A lens 21 is attached to the grip 40 to cover the window 42. The lens 21 is made or
printed with a scale. The scale includes two unit systems such as lb-ft and N-m. A
lens 29 is attached to the grip 40 to cover the window 49.
[0014] The torque-setting mechanism 101 includes a threaded rod 34, a threaded sleeve 35,
a bearing 38, a knob 70 and an indicator 28. The threaded rod 34 is connected to the
knob 70. The threaded rod 34 can be rotated but cannot be translated in the grip 40.
The threaded sleeve 35 can be translated but cannot be rotated in the grip 40. The
threaded sleeve 35 is engaged with the threaded rod 34. Thus, the knob 70 is operable
to rotate the threaded rod 34 to translate the threaded sleeve 35. The indicator 28
is connected to the threaded sleeve 35 so that they can be translated together. The
indicator 28 is observable via the lens 21. The position of the indicator 28 relative
to the scale made or printed on the lens 21 represents the maximum value of torque
set by the torque-setting mechanism.
[0015] The torque-relaying mechanism 102 includes a shank 20, a lever 30, a rolling unit
32 and a spring 36. The spring 36 is compressed between the threaded sleeve 35 and
the rolling unit 32. The rolling unit 32 is in detachable contact with an inclined
face formed at an end of the lever 30. The lever 30 is pivotally inserted in the shank
20, which is connected to the grip 40. The head 10 is formed at another end of the
lever 30.
[0016] The structures and operations of the torque-setting mechanism 101 and the torque-relaying
mechanism 102 will not be provided because they can be found in
US Patent No. 7182006.
[0017] The locking mechanism includes a sleeve 44, a body 50, a lever 60, a spring 64, two
caps 63, two pawls 65 and a switch 72. Each of the pawls 65 is formed with teeth 66.
[0018] Referring to FIG. 5, the sleeve 44 includes an axial space 41, two radial apertures
47 and 48 and teeth 46. The axial space 41 includes a large portion 43 and a small
portion 45, with a shoulder formed between them. The large portion 43 of the axial
space 41 is in communication with the radial aperture 47. The small portion 45 of
the axial space 41 is in communication with the radial aperture 48. The teeth 46 are
formed on an internal face of the sleeve 44, in the small portion 45 of the axial
space 41.
[0019] Referring to FIGS. 6 and 7, the body 50 includes two axial cavities 51 and 58, a
neck 52 formed at an end, an annular flange 54 formed near the neck 52, and two recesses
53 made near the annular flange 54. The axial cavity 58 is made in the neck 52. The
recesses 53 are in communication with the axial cavity 58 via a bore 55. The recess
53, the bore 55 and the axial cavity 58 together form a T-shaped channel. The body
50 further includes an axial aperture 56 in communication with the axial cavity 51.
The body 50 includes two more radial apertures 59 in communication with the axial
cavity 58. Two screw holes 57 are made in the annular flange 54.
[0020] Referring to FIG. 8, the knob 70 includes two axial cavities 71 and 75, an axial
bore 78 via which the axial cavity 71 is in communication with the axial cavity 75,
and a countersink hole 73. The knob 70 further includes teeth 76 formed on an internal
face, in the axial cavity 75.
[0021] Referring to FIG. 9, a scale ring 22 includes a scale 24 formed or printed with on
an external face and teeth 26 formed on the external face. The scale 24 includes smaller
units than the scale formed or printed on the lens 21.
[0022] Referring to FIGS. 3 and 4, the sleeve 44 is secured to the shank 20 via a screw
(not numbered). The scale ring 22 is placed on the sleeve 44. The pawls 65 are placed
in the recesses 53 and pivotally connected to the annular flange 54 by two pins 68.
The body 50, except the annular flange 54 and the neck 52, is inserted in the sleeve
44. The teeth 66 of the pawls 65 can be engaged with the teeth 46 of the sleeve 44.
[0023] The spring 64 includes a middle portion inserted in an aperture 62 made in the lever
60 and two ends inserted in the caps 63. The lever 60 includes a portion inserted
in the axial cavity 58 and the bore 55 of the body 50. A pin 67 is inserted in the
radial apertures 59 of the neck 52 and an aperture 61 made in the lever 60 to pivotally
connect the lever 60 to the body 50. The caps 63 are in contact with the pawls 65.
The lever 60 includes another portion inserted in axial bore 78 of the knob 70. A
screw 74 is inserted in the lever 60 via an axial aperture (not numbered) made in
the switch 72 to connect the switch 72 to the lever 60. A screw (not shown) is inserted
in the countersink hole 73 of the knob 70 and one of the screw holes 57 of the body
50 to connect the knob 70 to the body 50 so that they are rotatable together.
[0024] Referring to FIGS. 10 and 11, the switch 72 is pivoted into a first position like
a seesaw. Thus, the lever 60 is pivoted into a first position. Each of the caps 63
is abutted against a first portion of a corresponding one of the pawls 65 so that
the teeth 66 of the pawls 65 are engaged with the teeth 46 of the sleeve 44. The body
50 cannot be rotated relative to the sleeve 44. Therefore, the knob 70 cannot be rotated
relative to the shank 20.
[0025] Referring to FIGS. 12 and 13, the switch 72 is switched into a second position. The
lever 60 is pivoted into a second position. Each of the caps 63 is abutted against
a second portion of a corresponding one of the pawls 65 so that the teeth 66 of the
pawls 65 are disengaged from the teeth 46 of the sleeve 44. The body 50 can be rotated
relative to the sleeve 44. Hence, the knob 70 can be rotated relative to the shank
20.
[0026] Referring to FIGS. 14 to 16, there is a locking mechanism operable for locking a
torque-setting mechanism of a wrench according to a second embodiment of the present
invention. The second embodiment is like the first embodiment except several features.
Firstly, a switch 80 that can be translated relative to the grip 40 is used instead
of the switch 72 that can be pivoted relative to the grip 40. The switch 80 includes
a bore 82 for receiving an end of the lever 60. Secondly, the lever 60 can be translated,
instead of pivoted, relative to the body 50. Accordingly, the axial cavity 58 is a
groove adapted for movably receiving an end of the lever 60. Moreover, the neck 52
is made with two slots 90 for movably receiving two bosses 92 formed on the lever
60.
[0027] The present invention has been described via the detailed illustration of the embodiments.
Those skilled in the art can derive variations from the embodiments without departing
from the scope of the present invention. Therefore, the embodiments shall not limit
the scope of the present invention defined in the claims.
1. A locking mechanism for locking a knob relative to a grip, the locking mechanism including:
a sleeve non-movably connected to the grip and formed with teeth ;
a body non-movably connected to the knob, partially inserted in the sleeve, and formed
with at least one recess and a cavity in communication with the recess;
at least one pawl movably inserted in the recess and formed with teeth; and
a lever formed with an end for abutment against the pawl and movable in the cavity
of the body between a first position to press a first portion of the pawl to engage
the teeth of the pawl with the teeth of the sleeve and a second position to press
a second portion of the pawl to disengage the teeth of the pawl from the teeth of
the sleeve.
2. The lockable torque-setting mechanism according to claim 1, wherein the lever is pivotally
connected to the body.
3. The lockable torque-setting mechanism according to claim 1, wherein the lever is rectilinearly
movable in the cavity of the body.
4. The lockable torque-setting mechanism according to claim 1, further including a switch
operable to move the lever between the first and second positions.
5. The lockable torque-setting mechanism according to claim 4, wherein the switch includes
a bore for receiving the lever.
6. The lockable torque-setting mechanism according to claim 1, further including a spring
including a first end connected to the lever and a second end for pressing the pawl.
7. The lockable torque-setting mechanism according to claim 6, further including a cap
including a recess for receiving the second end of the spring and a dome for contact
with the pawl.
8. A wrench including:
a head;
a grip;
a torque-relaying mechanism for delivering torque to the head from the grip;
a torque-setting mechanism operable for setting a maximum value of torque deliverable
via the torque-relaying mechanism, wherein the torque-setting mechanism includes a
knob; and
a locking mechanism including:
a sleeve non-movably connected to the grip and formed with teeth;
a body non-movably connected to the knob, partially inserted in the sleeve, and formed
with at least one recess and a cavity in communication with the recess;
at least one pawl movably inserted in the recess and formed with teeth; and
a lever formed with an end for abutment against the pawl and movable in the cavity
of the body between a first position to press a first portion of the pawl to engage
the teeth of the pawl with the teeth of the sleeve and a second position to press
a second portion of the pawl to disengage the teeth of the pawl from the teeth of
the sleeve.
9. The wrench according to claim 8, wherein the lever is pivotally connected to the body.
10. The wrench according to claim 8, wherein the lever is rectilinearly movable in the
cavity of the body.
11. The wrench according to claim 8, wherein the locking mechanism further includes a
switch operable to move the lever between the first and second positions.
12. The wrench according to claim 11, wherein the switch includes a bore for receiving
the lever.
13. The wrench according to claim 8, wherein the locking mechanism further includes a
spring including a first end connected to the lever and a second end for pressing
the pawl.
14. The wrench according to claim 13, wherein the locking mechanism further includes a
cap including a recess for receiving the second end of the spring and a dome for contact
with the pawl.