Head of a wrench handle

Details Head of a wrench handle Head of a wrench handle

2001-12-27

2002-09-17

Smith, James G. (Department: 3723)

Tools

Wrench, screwdriver, or driver therefor

Handle clutched to head

C081S061000, C081S063100

Reexamination Certificate

active

06450066

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a head of a wrench handle with an improved torque-bearing capacity without increasing the manufacturing cost of the wrench.
2. Description of the Related Art
FIG. 1
of the drawings illustrates a handle head
100
of a conventional spanner type ratchet wrench. A gear
104
is rotatably mounted in a hole
100
a
in the head
100
and includes a polygonal inner periphery
101
for driving a fastener. The head
100
further includes a compartment
102
communicated with the hole
100
a
of the head
100
. A pawl
103
is mounted in the compartment
102
and engaged with the gear
104
. During ratcheting operation, the pawl
103
bears against a wall defining the compartment
102
at
105
, which corresponds the third teeth counting from the leftmost tooth of the pawl
103
in FIG.
1
. As can be seen from
FIG. 1
, the right portion of the pawl
103
is not supported such that when the force imparted to the pawl
103
reaches a critical value, no reactive force is obtained, and the pawl
103
will be disengaged from the gear
104
and move like a seesaw. The first three teeth will be damaged. This is owing to the fact that the compartment
103
is too shallow such that the pawl
103
merely engages with the gear
104
by only three effective teeth during the ratcheting operation. As a result, the torque-bearing capacity of the pawl
103
is poor. Enlargement of the head
100
would improve the torque-bearing capacity, yet the enlargement would contradict the benefit of the use of the spanner type ratchet type in a limited space.
FIG. 2
illustrates a pawl
106
having two centers E and F of curvatures. Namely, the pawl
106
includes a toothed side having a first teeth section
106
a
with a center E of curvature and a second teeth section
106
b
with a center F of curvature located at a position other than the center E of curvature. This allows more teeth of the pawl
106
in the compartment
108
to engage with the teeth
107
a
of the drive gear
107
of the wrench. Thus, during ratcheting, the second teeth portion
106
b
would not engage with the drive gear
107
when the first teeth portion
106
a
engages with the drive gear
107
and vice versa. This allows a stable, balanced operation of the pawl
106
during ratcheting, and the torque-bearing capacity was improved by 30%. Such a pawl has been disclosed in Applicant's U.S. patent application Ser. No. 09/523,625 filed on Mar. 13, 2000.
FIG. 3
illustrates a handle head of another wrench. The head
109
comprises a hole
109
c
for rotatably receiving a drive gear
109
d
. The head
109
further includes a compartment
109
a
communicated with the hole
109
c
, and a pawl
110
is slidably received in the compartment
109
a
. A cavity
109
e
is defined in a wall defining the compartment
109
a
, and a rigid pin
109
b
is fixed in the cavity
109
e
. The pawl
110
includes a toothed first side and a second recessed side
110
c
having two inclined faces
110
e
. The pawl
110
further includes two ends
110
b
. Thus, during ratcheting, the pawl
110
is supported at one of the ends
110
b
that bears against a side of the wall defining the compartment
109
a
and at one of the inclined faces
110
b
that bears against the rigid pin
109
b
. Almost all of the teeth of the pawl
110
are engaged with the drive gear
109
d
. Undesired disengagement of the pawl
110
from the drive gear
109
d
is prevented, and the torque-bearing capacity is improved. But the manufacturing cost is increased. Such a wrench has been disclosed in Applicant's U.S. patent application Ser. No. 09/916,796 filed on Jul. 27, 2001.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a head of a wrench handle with an improved torque-bearing capacity without increasing the manufacturing cost of the wrench.
In accordance with one aspect of the invention, a head of a wrench comprises a hole having a center and a radius. The head further includes a compartment communicated with the hole. A wall defining the compartment has a center of curvature and a radius of curvature. A ratio between the radius (RB) of curvature of the wall and the radius (RA) of the hole and is defined as follows:
(0.5≦
RB/RA<
1)
and
A distance (R
1
) between the center of the hole and the center of curvature of the wall is defined as follows:
R
1
>RA−
0.328*
RB
The present invention also provides a way to figure out a pawl for cooperating with the compartment thus formed.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.


REFERENCES:
patent: 15482 (1856-08-01), Gilman
patent: 810599 (1906-01-01), Ansorge
patent: 841686 (1907-01-01), Hatfield
patent: 893097 (1908-07-01), Reams
patent: 915446 (1909-03-01), Kearnes
patent: 1033358 (1912-07-01), Turner
patent: 1194471 (1916-08-01), Boosinger
patent: 1261092 (1918-04-01), Allen
patent: 1382492 (1921-06-01), Evans
patent: 1426127 (1922-08-01), Tuttle
patent: 1614039 (1927-01-01), Mandl
patent: 1957462 (1934-05-01), Kress
patent: 2317461 (1943-04-01), Jackson
patent: 2542241 (1951-02-01), Fors
patent: 2657604 (1953-11-01), Rueb
patent: 2701977 (1955-02-01), Stone
patent: 2764048 (1956-09-01), Thompson
patent: 2769360 (1956-11-01), Cottrell et al.
patent: 2800821 (1957-07-01), Fruscella
patent: 2891434 (1959-06-01), Lozensky
patent: 2957377 (1960-10-01), Hare
patent: 3019682 (1962-02-01), Hare
patent: 3250157 (1966-05-01), Badger
patent: 3337014 (1967-08-01), Sandrick
patent: 3393587 (1968-07-01), Jolliff et al.
patent: 3393780 (1968-07-01), Kilness
patent: 3436992 (1969-04-01), Over et al.
patent: 3577816 (1971-05-01), Alexander et al.
patent: 3713356 (1973-01-01), Knudsen
patent: 3742788 (1973-07-01), Priest
patent: 3838614 (1974-10-01), O'Donnell
patent: 3908487 (1975-09-01), Plaw
patent: 4070932 (1978-01-01), Jeannotte
patent: 4111077 (1978-09-01), Cummings et al.
patent: 4128025 (1978-12-01), Main et al.
patent: 4274311 (1981-06-01), Ebert
patent: 4277989 (1981-07-01), Tracy
patent: 4277990 (1981-07-01), Hall
patent: 4308768 (1982-01-01), Wagner
patent: 4308769 (1982-01-01), Rantanen
patent: 4328720 (1982-05-01), Shiel
patent: 4336728 (1982-06-01), Diebert
patent: 4406186 (1983-09-01), Gummow
patent: 4420995 (1983-12-01), Roberts
patent: 4485700 (1984-12-01), Colvin
patent: 4488460 (1984-12-01), Ballone et al.
patent: 4520697 (1985-06-01), Moetteli
patent: 4631988 (1986-12-01), Colvin
patent: 4662251 (1987-05-01), Kohal
patent: 4709600 (1987-12-01), Mierbach et al.
patent: 4722252 (1988-02-01), Fulcher et al.
patent: 4722253 (1988-02-01), Chow
patent: 4762033 (1988-08-01), Chow
patent: 4770072 (1988-09-01), Neuhaus
patent: 4796492 (1989-01-01), Liou
patent: 4807500 (1989-02-01), Main
patent: 4862775 (1989-09-01), Chow
patent: 4869138 (1989-09-01), Farris
patent: 4903554 (1990-02-01), Colvin
patent: 4934220 (1990-06-01), Slusar et al.
patent: 4986147 (1991-01-01), Cooper
patent: 4991468 (1991-02-01), Lee
patent: 5012705 (1991-05-01), Chow
patent: 5076121 (1991-12-01), Fosella
patent: 5144869 (1992-09-01), Chow
patent: 5157994 (1992-10-01), Krivec
patent: 5178047 (1993-01-01), Arnold et al.
patent: 5199330 (1993-04-01), Arnold et al.
patent: 5199335 (1993-04-01), Arnold et al.
patent: 5230262 (1993-07-01), Ahlund et al.
patent: 5231903 (1993-08-01), Bockman, Jr.
patent: 5233891 (1993-08-01), Arnold et al.
patent: 5271300 (1993-12-01), Zurbuchen et al.
patent: 5295422 (1994-03-01), Chow
patent: 5392672 (1995-02-01), Larson et al.
patent: 5425291 (1995-06-01), Chang
patent: 5467672 (1995-11-01), Ashby
patent: 5477757 (1995-12-01), Maresh
patent: 5495783 (1996-03-01), Slusar et al.
patent: 5499560 (1996-03-01), Aeschiliman
patent: 5501124 (1996-03-01), Ashby
patent: 5509333 (1996-04-01), Rion
patent: 5533427 (1996-07-01), Chow
patent: 3265171 (1996-08-01), Kilness
patent: 5557994 (1996-09-01), Nakayama
patent: 5595095 (1997-01-01), Hillinger
patent: 5626061 (1997-05-0

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