Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Reexamination Certificate
2000-11-27
2001-11-13
Meislin, D. S. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
Reexamination Certificate
active
06314839
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to reversible rachet wrenches. More particularly, this invention relates to a reversible rachet wrench which is rugged, has a reversing mechanism comprising only three moving parts, and costs less to produce than other, more complicated designs.
BACKGROUND OF THE INVENTION
Reversible rachet wrenches are well known. While there are numerous different designs, a typical reversible rachet wrench includes a head portion and a handle portion. Mounted in the head portion is a toothed rachet wheel and a socket pin. The head also includes a pivotal pawl element or member and a mechanism to pivot the pawl element from a first position (where the rachet wheel rotates in a clockwise direction) to a second position (where the rachet wheel rotates in a counterclockwise direction).
The mechanisms for effecting reversal of the direction of the rachet wheel are quite varied. Perhaps the most common mechanism is illustrated in FIGS. 1 and 2 of U.S. Pat. No. 5,761,972 to J. A. Sanders. The direction reversal mechanism includes a two position pawl
27
which engages rachet wheel
18
(referred to as a spur gear) for rotating of the socket pin
16
in either a clockwise or counterclockwise direction. The pawl assembly includes a pawl lever
24
connected, via shaft
26
, to the pawl
27
for switching, as desired by the user, between engagement for clockwise or counterclockwise rotation of the rachet wheel and socket pin. Sanders also includes an advancing lever
30
, extending from a slot in the side of handle
14
for “finger” tightening or loosening.
U.S. Pat. No. 4,254,675 to Marlow et al., discloses a reversible rachet wench which includes a head portion, a handle portion
14
, a toothed rachet wheel
24
and a pawl element
34
. Reversal of the direction of pawl
34
is effected by a mechanism that includes a control rod
52
having an enlarged end
54
with an offset bore
58
(in which is received spring
60
and pawl engaging pin
62
). The opposite end of rod
52
is connected to barrel
70
via cap
78
. When it is desired to reverse the rotational direction of rachet wheel
24
, the operator merely pushes barrel
70
toward the head until a detent enters notch
64
, and then rotates barrel
70
in either a clockwise or counterclockwise direction. As barrel
70
rotates so does control rod
52
and pin
62
. Since the pin is eccentrically mounted, it rides up or down the engaged cam surface (
98
or
100
) of pawl element
34
until it reaches junction
102
. Continued rotation of barrel
70
moves the pin past the junction and as it does spring
60
releases its energy and forces pin
62
outwardly against the newly engaged cam surface and forces the pawl element
34
to rotate quickly to engage the other pawl member
84
,
86
with the wheel
24
, thereby permitting rotation of the rachet wheel in the direction opposite of the initial direction and preventing rotation in the initial direction.
Other direction reversing mechanisms are illustrated in U.S. Pat. No. 4,869,138 (J. L. Ferris), U.S. Pat. No. 4,967,624 (J. L. Ferris), U.S. Pat. No. 4,274,311 (E. Ebert), U.S. Pat. No. 3,659,484 (G. L. Scodeller), U.S. Pat. No. 4,457,107 (S. Waiser), U.S. Pat. No. 5,582,080 (T. C. Barmore), U.S. Pat. No. 5,957,008 (P. S. Long), and U.S. Pat. No. 4,631,990 (M. E. Hughes). All the foregoing suffer from the drawback that they include numerous parts, all of which increases manufacturing costs and reduces reliability.
OBJECTS OF THE INVENTION
It is the object of the present invention to provide for a reversible rachet wrench which is simple in design, has few moving parts, is cheap and easy to manufacture, rugged, and convenient for the operator to reverse the directional rotation of the rachet in tight working conditions.
These, and other objects will be obvious from the following description.
SUMMARY OF THE INVENTION
The reversible rachet wrench of the present invention includes: a support body having a head portion and a handle support portion having a cylindrically shaped section; a rachet wheel having teeth extending around the perimeter thereof, rotatably supported by the head portion; a pawl member; a pivot member; and a rotatable handle. The pawl member, which is pivotally supported by the head portion, includes a pair of spaced apart teeth engaging members, which are alternatively engagable with the teeth on the rachet wheel. The pivot member, pivotally supported on the support body, includes first and second ends and an intermediate pivot point. The first end includes a means for engaging the coupling means provided on the pawl member. The second end includes a means for engagement with the rachet handle. The handle, which is rotatably supported on the cylindrically shaped section, includes a first end having a recess for receiving the second end of said pivot member, whereby rotation of the handle about the cylindrically shaped section moves the pivot member about the pivot point, thereby moving the pawl member from a first position to a second position. The handle rotates relative to the cylindrically shaped section through an angle of less than 360°, preferably 40°-60°. Optionally, the first end of the handle includes a second, longer recess for receiving the second end of the pivot member. The handle support portion is solid and integral with the head portion. Finally, the wrench includes a spring biased detent which is biased into engagement with either one or the other of two surfaces provided on the pawl member.
REFERENCES:
patent: 4254675 (1981-03-01), Marlow et al.
patent: 4274311 (1981-06-01), Ebert
patent: 4967624 (1990-11-01), Farris
patent: 5761972 (1998-06-01), Sanders
patent: 5957008 (1999-09-01), Long
Meislin D. S.
Morgan DeWitt M.
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