Tools – Wrench – screwdriver – or driver therefor – Machine
Reexamination Certificate
2001-04-12
2002-12-10
Smith, James G. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Machine
C081S063200
Reexamination Certificate
active
06490953
ABSTRACT:
FIELD OF THE INVENTION
The present invention is generally a novel powered ratchet head design. More specifically, the present invention is a ratchet head design having external features for retaining the ratchet mechanism within the head.
BACKGROUND OF THE INVENTION
Various powered ratchet wrench designs have been designed, manufactured and marketed. As shown in
FIG. 1
, the prior art design is shown at
10
having a head portion
12
and a handle portion
14
. Within head portion
12
is a ratchet mechanism
16
, which is enclosed within a yoke
18
. Handle portion
14
includes a housing
20
which encloses a drive motor, not shown. Generally, such drive motors have been pneumatic, but other motors have been utilized. The end of handle portion
14
contains a compressed air inlet port
22
, which connects to a compressed air supply by various means known in the art. An actuation button or lever
24
is located between air inlet port
22
and housing
20
, which allows the operator to actuate the pneumatic motor, the drive mechanism (not shown) and ratchet mechanism
16
.
As shown in
FIG. 2
, the prior art ratchet mechanism
16
contains a shift lever
25
, a pawl
28
and a ratchet body
30
having a drive square
26
. Alternatively, ratchet mechanism
16
may contain more than one pawl
28
. Ratchet mechanism
16
fits within yoke
18
in order to allow for rotation of drive square
26
caused by interaction of pawl
28
and the teeth formed on yoke
18
.
When assembled, ratchet mechanism
16
is retained within ratchet head
12
on one end by ear
11
of ratchet housing
12
, which is in contact with the upper end of ratchet body
30
, opposite drive square
26
, and on the other end by an internal snap ring
32
, which fits within a groove
34
formed within ear
13
, of ratchet head
12
. Between snap ring
32
and the lower end of ratchet body
30
is provided a tensioning means, such as a compressed belleville spring washer
31
, for example. The belleville spring washer or belleville washer
31
, is held in a compressed state between the lower end of ratchet body
30
and snap ring
32
. Compressed belleville washer
31
biases ratchet body
30
toward ear
11
of head portion
12
and provides friction for ratchet mechanism
16
. This friction is commonly referred to in the art as head tension or simply tension, and allows for advancement of ratchet mechanism
16
within yoke
18
, as yoke
18
moves with reciprocating motion within ratchet head
12
.
Because the ratchet mechanism
16
is retained internally within ratchet housing
12
between ears
11
and
13
, when torque is applied to the ratchet head, the ears
11
,
13
of ratchet head
12
begin to widen apart or spread. Upon repeated application of torque to ratchet head
12
, ears
11
and
13
may remain in a spread position. This causes ratchet mechanism
16
to function improperly and slip upon application of force to drive square
26
because ears
11
and
13
no longer hold the tensioning means in a compressed state, and the resulting loss of tension between the tensioning means, for example a belleville spring washer, and the ears
11
and
13
does not allow ratchet mechanism
16
to advance within yoke
18
. This is a significant problem in prior art ratchet head designs and increases the costs to maintain these ratchet wrenches for both the end user/owner and the ratchet wrench manufacturers.
Therefore, there is a need for an improved ratchet head design which prevents spreading of the ratchet head ears and thus, maintains proper operation of the ratchet mechanism of the pneumatic ratchet wrench.
SUMMARY OF THE INVENTION
It is a general object of the present invention to provide a powered ratchet wrench design which prevents spreading of the ratchet head, and thus proper operation of the ratchet wrench.
It is another object of the present invention to provide a powered ratchet wrench design which contains components which are easily replaceable upon excess wear.
It is yet another object of the present invention to provide a powered ratchet wrench that has decreased maintenance costs.
These and other objects of the present invention are accomplished by providing a ratchet head design which externally captures the ratchet mechanism between the ears of the ratchet head. Capturing the ratchet mechanism externally prevents the ears from spreading. The present invention also provides easily and rather inexpensively replaceable wear washers positioned adjacent the wear surfaces of the ratchet head. Through the prevention of spreading of the ratchet head and having replaceable wear surfaces, the life of the tool is increased.
REFERENCES:
patent: 2764048 (1956-09-01), Thompson
patent: 3529498 (1970-09-01), Northcutt
patent: 4903554 (1990-02-01), Colvin
patent: 5086673 (1992-02-01), Korty
patent: 5140874 (1992-08-01), Junkers
patent: 5142952 (1992-09-01), Putney et al.
patent: 5178047 (1993-01-01), Arnold et al.
patent: 5199330 (1993-04-01), Arnold et al.
patent: 5231901 (1993-08-01), Putney et al.
patent: 5237885 (1993-08-01), Putney et al.
patent: 5309714 (1994-05-01), Putney et al.
patent: 5425291 (1995-06-01), Chang
patent: 5450773 (1995-09-01), Darrah et al.
patent: 5537899 (1996-07-01), Diedrich
patent: 5630343 (1997-05-01), Begin
patent: 5697267 (1997-12-01), Tsai
patent: 5896789 (1999-04-01), Giardino
patent: 6067881 (2000-05-01), Albertson
Four (4) Photograph of a Prior Art Snap-On Air Ratchet Undated.
One (1)Copy of the Owner's Manual of the Snap-On Air Ratchet, (Undated).
Bommarito, Esq Alexander D
Hahn Loeser + Parks LLP
Mechanics Custom Tools Corp.
Smith James G.
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