[0001] The invention relates to a control device for ratchet wrenches.
[0002] The closest prior art of which applicant is aware is his prior U.S. Patent No. 4,862,775
to Chow, entitled "CONTROL DEVICE FOR RATCHET WRENCHES", filed October 19, 1988. In
this ratchet wrench, the knob is caused to move along the groove of the control element
in order to switch the rotational directions of the ratchet wrench; however, the knob
can not move along the groove of the control element smoothly.
[0003] The objective of the invention is to provide a control device of a ratchet wrench
which can be operated smoothly.
[0004] A ratchet wrench comprising a housing including a recess formed in an upper portion
thereof and enclosed by a cover, a ratchet wheel rotatably disposed in a first end
of the housing, a pawl pivotally disposed in the first end of the housing and including
a first tooth and a second tooth for engagement with the ratchet wheel respectively,
a depression formed in one side of the pawl, a slide slidably disposed in the recess
and including a slit formed therein, and a resilient member including a first end
engaged in the slit of the slide and a second end slidably engaged with the depression,
whereby, the first tooth and the second tooth of the pawl are caused to engage with
the ratchet wheel respectively when the pawl is rotated by engagement between the
second end of the resilient member and the depression of the pawl and when the slide
is pushed toward and away from the pawl.
FIG. 1 is an exploded view of a ratchet wrench;
FIGS. 2, 3 and 4 are top plane view of the ratchet wrench, with the cover removed,
illustrating the operations of the ratchet wrenches.
[0005] Referring to FIGS. 1 and 2, a ratchet wrench comprises a housing 10 including a recess
11 formed in the upper portion and enclosed by a cover 30, a cap 36 enclosing the
lower portion of the housing 10 and including two openings formed therein, a ratchet
wheel 16 rotatably received in the first end of the housing 10, and a pawl 15 rotatably
rotatably supported in the housing 10 by a pin 33 which is fixed between the cover
30 and the cap 36, the pawl 15 including a curved depression 151 formed in one side
portion thereof and a first tooth 152 and a second tooth 153 formed thereon for engagement
with the ratchet wheel 16 respectively.
[0006] The control device for the ratchet wrench includes a block 12 formed integral in
the middle portion of the recess 11 of the housing 10 and having a hole 121 and a
notch 122 formed therein, a stop 13 formed in the housing 10 and located between the
first end of the housing 10 and the block 12, a slide 20 slidable between the stop
13 and the block 12 and including an orifice 21 and a slit 22 formed therein, an extension
201 extended from the slide 20 and slidably engaged in the notch 122 of the block
12 and having a hole 23 formed therein, a sprang 14 engaged in the holes 121 and 23
of the block 12 and the extension 201 of the slide 20, and a resilient member 24 including
a flange 241 formed in one end for engagement in the slit 22 of the slide 20 and a
bent portion 242 formed in the other end for slidable engagement with the curved depression
151 of the pawl 15, and a knob 32 including a stub 321 extended downward through the
oblong hole 31 of the cover 30 and engaged in the orifice 21 of the slide 20 in order
to move the slide 20, the stop 13 and the block 12 limit the movements of the slide
20.
[0007] In operation, referring next to FIGS. 2, 3 and 4, when the slide 20 is moved rearward
to the position as shown in FIG. 2, the first tooth 152 of the pawl 15 is caused to
engage with the ratchet wheel 16 such that the ratchet wheel 16 can not rotate clockwise
and is rotatable counterclockwise. When the slide 20 is moved to the middle position
as shown in FIG. 3, both the teeth 152, 153 of the pawl 15 are not engaged with the
ratchet wheel 16 such that the ratchet wheel 16 is rotatable in both directions. When
the slide 20 is moved forward to the position as shown in FIG. 4, the second tooth
153 of the pawl 15 is caused to engage with the ratchet wheel 16 such that the ratchet
wheel 16 can not rotate counterclockwise and is rotatable clockwise.
[0008] It is preferable that the spring 14 is a compression and coil spring and arranged
such that the slide 20 can be maintained at the positions as shown in FIGS. 2 to 4.
[0009] Accordingly, the control device for the ratchet wrench can be operated smoothly.
1. A ratchet wrench comprising a housing (10) including a recess (11) formed in an upper
portion and enclosed by a cover (30), a ratchet wheel (16) rotatably disposed in a
first end of said housing (10), a pawl (15) pivotally disposed in said first end of
said housing (10) and including a first tooth (152) and a second tooth (153) for engagement
with said ratchet wheel (16) respectively, a depression (151) formed in one side of
said pawl (15), a slide (20) slidably disposed in said recess (11) and including a
slit (22) formed therein, and a resilient member (24) including a first end (241)
engaged in said slit (22) of said slide (20) and a second end (242) slidably engaged
with said depression (151), whereby, said first tooth (152) and said second tooth
(153) of said pawl (15) are caused to engage with said ratchet wheel (16) when said
slide (20) is pushed toward and away from said pawl (15).
2. A ratchet wrench according to claim 1 further comprising means (12, 13) for limiting
movement of said slide (20).
3. A ratchet wrench according to claim 2, wherein limiting means (12, 13) includes a
block (12) formed in a middle portion of said recess (11) and a stop (13) formed in
said recess (11) and located between said block (12) and said pawl (15), said slide
(20) is slidable between stop (13) and said block (12).
4. A ratchet wrench according to claim 3, wherein said block (12) includes a notch (122)
formed therein, said slide (20) includes an extension (201) slidably engaged in said
notch (122) of said block (20).
5. A ratchet wrench according to claim 4 further comprising a spring (14) engaged between
said extension (201) of said slide (20) and said block (12).
6. A ratchet wrench comprising a housing (10) including a recess (11) formed in an upper
portion and enclosed by a cover (30), a ratchet wheel (16) rotatably disposed in a
first end of said housing (10), a pawl (15) pivotally disposed in said first end of
said housing (10) and including a first tooth (152) and a second tooth (153) for engagement
with said ratchet wheel (16), a depression (151) formed in one side of said pawl (15),
a slide (20) slidably disposed in said recess (11) and including a slit (22) formed
therein, a block (12) formed in a middle portion of said recess (11) and including
a notch (122) formed therein, said slide (20) including an extension (201) slidably
engaged in said notch (122) of said block (12), a spring (14) engaged between said
extension (201) of said slide (20) and said block (12), a stop (13) formed in said
recess (11) and located between said block (12) and said pawl (15), said slide (20)
being slidable between stop (13) and said block (12), and a resilient member (24)
including a first end engaged in said slit (22) of said slide (20) and a second end
slidably engaged with said depression (151), whereby, said first tooth (152) and said
second tooth (153) of said pawl (15) are caused to engage with said ratchet wheel
(16) when said slide (20) is pushed toward and away from said pawl (15).
