Tools – Wrench – screwdriver – or driver therefor – Handle or shank
Reexamination Certificate
2000-05-08
2001-12-11
Eley, Timothy V. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle or shank
C081S177100, C081S489000, C081S177850
Reexamination Certificate
active
06327941
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an extension structure for a tool, and more particularly to a socket wrench extension structure.
2. Description of the Related Art
A first conventional socket wrench extension
10
in accordance with the prior art shown in
FIG. 1
includes a first end formed with a connector
12
which can be coupled with a socket (not shown), and a second end formed with an enlarged head
14
which defines a square recess (not shown) therein for receiving a square head (not shown) of a socket wrench (not shown). The connector
12
includes a ball (not shown) provided thereon so that the socket can be tightly mounted on the connector
12
of the socket wrench extension
10
. However, the user has to exert a large force for detaching the socket from the connector
12
of the socket wrench extension
10
so that the socket cannot be quickly mounted on or detached from the connector
12
of the socket extension shank
10
, thereby causing inconvenience in operation of the socket extension shank
10
.
A second conventional socket wrench extension
20
in accordance with the prior art shown in
FIG. 2
includes a first end formed with a connector
22
for coupling with a socket (not shown), and a second end formed with an enlarged head
24
defining a hexagonal recess
21
therein for driving a screw (not shown). However, the user also has to exert a large force for detaching the socket from the connector
22
of the socket wrench extension
20
so that the socket cannot be quickly mounted on or detached from the connector
22
of the socket extension shank
20
, thereby causing inconvenience in operation of the socket extension shank
20
.
The closest prior arts of which the applicant is aware are disclosed in the following patents:
1. U.S. Pat. No. 5,289,745;
2. U.S. Pat. No. 5,720,207;
3. U.S. Pat. No. 6,006,632; and
4. U.S. Pat. No. 6,003,414.
In the above-mentioned four patens, an elongated channel is formed in the socket wrench extension so that the ball can be received into the connector of the socket wrench extension, thereby facilitating the socket being detached from the connector of the socket wrench extension. However, it is difficult to drill such an elongated channel in the socket wrench extension. In practice, a long drilling head with a smaller diameter is used for drilling the elongated channel in the socket wrench extension so that the drilling head is easily broken during the drilling process, thereby increasing the difficulty of working, increasing the time required for drilling the elongated channel, and increasing the cost of fabrication.
Another closest prior art of which the applicant is aware is disclosed in U.S. Pat. No. 5,813,296. In the above-mentioned patent, the ball can also be received into the connector of the socket wrench extension, thereby facilitating the socket being detached from the connector of the socket wrench extension. However, the socket wrench extension includes a complicated construction consisting of many parts, thereby greatly increasing the cost of fabrication.
SUMMARY OF THE INVENTION
The present invention has arisen to mitigate and/or obviate the disadvantage of the conventional socket wrench extension.
In accordance with one aspect of the present invention, there is provided a socket wrench extension structure comprising an elongated extension shank having one distal end defining a longitudinal circular chamber, a ball receiving hole defined in an outer periphery of the one distal end of the extension shank and connecting to the circular chamber, a knob receiving hole defined in the outer periphery of the one distal end of the extension shank and connecting to the circular chamber; a drive rod slidably mounted in the circular chamber and having a first end defining a ball receiving recess aligning with the ball receiving hole of the extension shank and a second end defining a knob receiving recess aligning with the knob receiving hole of the extension shank; a biasing member mounted in the circular chamber of the extension shank and biased between the second end of the drive rod and a wall of the circular chamber; a ball movably mounted in the ball receiving hole and slidably received in the ball receiving recess; and a press knob movably mounted in the knob receiving hole and slidably received in the knob receiving recess.
Preferably, the knob receiving recess includes an arcuate guide surface for guiding the press knob into the knob receiving recess.
Preferably, the second end of the drive rod includes a retaining stub extending outward and secured to the biasing member for retaining and limiting the biasing member.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.
REFERENCES:
patent: 5291809 (1994-03-01), Fox, III et al.
patent: 5531140 (1996-07-01), Chow
patent: 5752418 (1998-05-01), Robins
patent: 6006632 (1999-12-01), Hsieh
patent: 6062112 (2000-05-01), Bonniot
Berry Jr. Willie
Cheng Chin-Shun
Eley Timothy V.
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