Knockdown hand tool structure

Details Knockdown hand tool structure Knockdown hand tool structure

2000-09-13

2002-04-02

Smith, James G. (Department: 3723)

Tools

Wrench, screwdriver, or driver therefor

Having work engaging and force exerting portion inserted...

C081S439000

Reexamination Certificate

active

06363819

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a knockdown hand tool structure in which by means of V-shaped annular engaging grooves of the screwdriver stem, the projecting length thereof can be changed for application to various holes with different depths and diameters so as to tighten or untighten a screw or a nut. The use and replacement of the screwdriver stem are facilitated and quickened and the cost for additional screwdriver stem is saved. Also, the occupied room is reduced to facilitate carriage of the hand tool.
FIG. 1
shows a conventional hand tool including a grip
10
and a socket
50
. The grip
10
is connected with a stem
11
forward projecting from the center of the front end face of the grip
10
by a certain length. The front end section of the stem
11
is formed with a rectangular fitting section
12
. A steel ball
13
is inlaid in one side of the fitting section
12
. The rear end of the socket
50
is formed with a rectangular fitting hole
51
. The front end of the socket
50
is formed with a polygonal tool socket
52
.
When assembled, as shown in
FIG. 2
, the fitting section
12
of the grip
10
is fitted into the fitting hole
51
of the socket
50
with the steel ball
13
engaged with the socket
50
so as to fix the socket
50
with the grip
10
. When replacing the socket
50
with another with different specification, the socket
50
is directly drawn outward and separated from the grip
10
.
The above conventional hand tool has some shortcomings as follows:
1. The fitting section
12
of the grip
10
can be only fitted with the socket
50
and cannot be co-used with different screwdriver stems with various specifications or types of screwdriver heads. Therefore, the application range is narrower.
2. The stem
11
of the grip
10
is not adjustable in length. Therefore, in use, it is necessary to replace the grip
10
with different length of stem
11
in accordance with the requirement of application situation. This is troublesome and inconvenient. Also, it is necessary to purchase various kinds of grips
10
and the cost is increased.
FIG. 3
shows another type of conventional hand tool including a grip
20
, a screwdriver stem
30
, a fitting stem
40
and a socket
50
. The grip
20
is connected with a hexagonal stem
21
forward projecting from the center of the front end face of the grip
20
by a certain length. The front end section of the stem
21
is connected with an enlarged fitting head
22
. The front end of the fitting head
22
is formed with a central hexagonal fitting hole
23
. A steel ball
24
is inlaid in one side of the fitting hole
23
. The screwdriver stem
30
is a hexagonal stem body. The front end of the screwdriver stem
30
is formed with a cross-shaped screwdriver head
31
. (The screwdriver head
31
can be otherwise shaped.) The fitting stem
40
is a hexagonal stem body having a rectangular fitting section
41
at front end. A steel ball
42
is inlaid in one side of the fitting section
41
. The rear end of the socket
50
is formed with a rectangular fitting hole
51
. The front end of the socket
50
is formed with a polygonal tool socket
52
.
When assembled, as shown in
FIG. 4
, the rear section of the screwdriver stem
30
is inserted into the fitting hole
23
of the fitting head
22
of the grip
20
. By means of the steel ball
24
in the fitting hole
23
, the screwdriver stem
30
is fixedly engaged with the grip
20
for use of the screwdriver stem
30
. When applied to a nut, as shown in
FIG. 5
, the screwdriver stem
30
is first extracted from the fitting hole
23
. Then the rear section of the fitting stem
40
is inserted into the fitting hole
23
of the fitting head
22
of the grip
20
. By means of the steel ball
24
in the fitting hole
23
, the fitting stem
40
is fixedly engaged with the grip
20
. Then the fitting section
41
of the fitting stem
40
is fitted into the fitting hole
21
of rear end of the socket
50
. By means of the steel ball
42
of the fitting section
41
, the fitting stem
40
is fixedly engaged with the socket
50
for use of the socket
50
.
The above conventional hand tool has some shortcomings as follows:
1. The fitting head
22
of the stem
21
of the grip
20
is enlarged. In the case that the screwdriver stem
30
is used to tighten a screw into a narrower hole with smaller inner diameter, the fitting head
22
may be stopped by the outer edge of the hole to make the screwdriver stem
30
impossible to extend to the screw.
2. When it is desired to further use the screwdriver stem
30
after using the socket
50
, it is necessary to extract the fitting stem
40
and the socket
50
and then again insert the rear section of the screwdriver stem
30
into the fitting hole
23
of the fitting head
22
of the grip
20
. Such procedure is troublesome and time-consuming.
3. The stem
21
of the grip
20
has fixed length which cannot be adjusted. Therefore, in use, it is necessary to replace the screwdriver stem
30
or fitting stem
40
with one with different length or specification or pattern in accordance with the requirement of application situation. This is troublesome and inconvenient. Also, it is necessary to purchase various kinds of screwdriver stems
30
and fitting stems
40
so that the cost is increased.
SUMMARY OF THE INVENTION
It is therefore a primary object of the present invention to provide a knockdown hand tool structure in which in the case that a screw is tightened in a narrower hole, the body of the screwdriver stem is slender and has unified diameter so that the screwdriver stem can easily extend into the narrower hole to drive the screw.
It is a further object of the present invention to provide the above knockdown hand tool structure in which the fitting post and the socket are fitted on the screwdriver head of the screwdriver stem. In the case that it is desired to further use the screwdriver stem after using the socket, a user only needs to extract the fitting post and the socket and then the screwdriver stem can be directly used. Therefore, it is no more necessary to extract the socket and then insert the screwdriver stem and the replacement is facilitated and quickened.
It is a further object of the present invention to provide the above knockdown hand tool structure in which in use, the screwdriver stem can be directly inward or outward moved to change the length thereof as necessary. Alternatively, the screwdriver stem can be extracted and turned over to use the other screwdriver head with different specification or pattern. Therefore, the use is facilitated and it is unnecessary to purchase additional screwdriver stem so that the cost is saved and the occupied space is reduced to facilitate carriage of the hand tool.
The present invention can be best understood through the following description and accompanying drawings wherein:


REFERENCES:
patent: 1203853 (1916-11-01), Contal
patent: 1269413 (1918-06-01), Finnigan
patent: 4399723 (1983-08-01), Marleau
patent: 4409866 (1983-10-01), McBride
patent: 4586406 (1986-05-01), Howard
patent: 5732606 (1998-03-01), Chiang
patent: 5836223 (1998-11-01), Lin
patent: 5931065 (1999-08-01), Jackson et al.
patent: 5964132 (1999-10-01), Chen

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