Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Reexamination Certificate
2000-04-03
2001-09-04
Smith, James G. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
C081S060000, C081S063000
Reexamination Certificate
active
06282991
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a biasing arrangement for a pawl of a reversible ratchet-type wrench to provide reliable ratcheting.
2. Description of the Related Art
U.S. Pat. No. 2,957,377 issued to Hare on Oct. 25, 1960 discloses a reversible ratchet type wrench comprising a body
10
having a handle
11
and a head
12
. A cap
39
and an annular wall
44
are provided to upper side and lower side of the head
12
, respectively. Yet, this increases the assembly time and the manufacture cost and adversely affects the appearance. A shifting lever
35
is retained in place by a spring
33
that is located in a cylindrical opening
34
. Nevertheless, formation of the cylindrical opening
34
that extends upward at air incline relatively difficult. In addition, formation of the cavity
16
having converging straight sides
17
,
18
which diverge in the direction of the periphery of rotatable member
14
requires expensive and accurate computer-numeric-control (CNC), which further results in an increase in the cost together with a low production rate. This is why such a reversible ratchet type wrench is hardly seen in the market.
FIGS. 9 and 10
illustrate another conventional ratchet type wrench comprising a handle
12
′ and a head
11
′. The head
11
′ is machined to form four consecutive compartments for receiving the drive member
20
′, the pawl
30
′ and the shifting lever
40
′, wherein three of the compartments can be formed by cutting, yet the remaining one must be machined by CNC. Further, the resultant head structure is relatively weak and thus has a poor torque-bearing capacity. In addition, the movement of the pawl
30
′ for changing ratcheting direction is found unreliable, as it is achieved via transmission of the hook end
442
′ of a spring
44
′ attached to the shifting lever
40
′.
SUMMARY OF THE INVENTION
A reversible ratchet-type wrench in accordance with the present invention comprises:
a handle;
a head extended from the handle and including a hole, a web being defined between the handle and the head, a first cavity being defined in the web and communicated with the hole, the web further including a compartment communicated with the first cavity, the web further including a second cavity that is communicated with the compartment;
a drive member rotatably mounted in the hole of the head, the drive member including a plurality of teeth formed on an outer periphery thereof;
a pawl mounted in the first cavity and including a first side with a plurality of ratchet teeth for releasably engaging with the teeth of the drive member;
a switch member rotatably received in the compartment of the web, the switch member being switchable between two ratcheting positions for changing ratcheting direction of the drive member;
means mounted between the switch member and the pawl for urging the ratchet teeth of the pawl to engage with the teeth of the drive member; and
means mounted in the second cavity for positioning the switch member in one of the two ratcheting positions.
In an embodiment of the invention, a reversible ratchet-type wrench comprises:
a handle;
a head extended from the handle and including a hole, a web being defined between the handle and the head, a first cavity being defined in the web and communicated with the hole, the web further including a compartment communicated with the first cavity, the web further including a second cavity that is communicated with the compartment;
a drive member rotatably mounted in the hole of the head, the drive member including a plurality of teeth formed on an outer periphery thereof;
a pawl mounted in the first cavity and including a first side with a plurality of ratchet teeth for releasably engaging with the teeth of the drive member, the pawl further includes a second side with a recess that faces the compartment;
a coil spring having a first end slidably received in the recess and a second end;
a switch member including a turn-piece and an actuating plate extended from the turn-piece and rotatably received in the compartment of the web, the switch member being switchable between two ratcheting positions for changing ratcheting direction of the drive member, the actuating plate including a first side that faces the first cavity and a second side that faces away from the first cavity, the first side of the actuating plate including a receptacle that has an inner receptacle section and an enlarged outer receptacle section for receiving the second end of the coil spring, the second side of the actuating plate including two positioning grooves;
the coil spring urging the ratchet teeth of the pawl to engage with the teeth of the drive member; and
an elastic element mounted in the second cavity and a ball biased by the elastic element so as to be partially engaged in one of the two positioning grooves.
In another embodiment of the invention, a reversible ratchet-type wrench comprises:
a handle;
a head extended from the handle and including a hole, a web being defined between the handle and the head, a first cavity being defined in the web and communicated with the hole, the web further including a compartment communicated with the first cavity, the web further including a second cavity that is communicated with the compartment;
a drive member rotatably mounted in the hole of the head, the drive member including a plurality of teeth formed on an outer periphery thereof;
a pawl mounted in the first cavity and including a first side with a plurality of ratchet teeth for releasably engaging with the teeth of the drive member, the pawl further includes a second side with a recess that faces the compartment;
a pin having a first end slidably received in the recess and a second end;
a switch member including a turn-piece and an actuating plate extended from the turn-piece and rotatably received in the compartment of the web, the switch member being switchable between two ratcheting positions for changing ratcheting direction of the drive member, the actuating plate including a first side that faces the first cavity and a second side that faces away from the first cavity, the first side of the actuating plate including a receptacle for receiving the second end of the pin, the second side of the actuating plate including two positioning grooves; and
an elastic element mounted in the second cavity and a ball biased by the elastic element so as to be partially engaged in one of the two positioning grooves, and the pin urging the ratchet teeth of the pawl to engage with the teeth of the drive member when the switch member is retained in one of the two ratcheting positions corresponding to positioning of the ball in the positioning grooves.
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: 1382492 (1921-06-01), Evans
patent: 2957377 (1960-10-01), Hare
patent: 3019682 (1962-02-01), Hare
patent: 3265171 (1966-08-01), Kilness
patent: 4128025 (1978-12-01), Main et al.
patent: 4770072 (1988-09-01), Neuhaus
patent: 5076121 (1991-12-01), Fosella
patent: 5157994 (1992-10-01), Krivec
patent: 5178047 (1993-01-01), Arnold et al.
patent: 5230262 (1993-07-01), Ahlund et al.
patent: 5233891 (1993-08-01), Arnold et al.
patent: 5533427 (1996-07-01), Chow
patent: 5626062 (1997-05-01), Colvin
patent: 5857390 (1999-01-01), Whiteford
patent: 5957009 (1999-09-01), McCann
patent: 5964129 (1999-10-01), Shiao
patent: 6065374 (2000-05-01), Taggart
patent: 6164167 (2000-12-01), Chen
Kamrath Alan
Rider Bennett Egan & Arundel LLP
Shakeri Hadi
Smith James G.
LandOfFree
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