U.S. patent number 3,604,488 [Application Number 04/877,894] was granted by the patent office on 1971-09-14 for screwdriver attachment.
This patent grant is currently assigned to Vermont American Corporation. Invention is credited to Paul R. Blondin, James L. Wishart.
United States Patent |
3,604,488 |
Wishart , et al. |
September 14, 1971 |
SCREWDRIVER ATTACHMENT
Abstract
A screwdriver attachment which can be quickly mounted on and
removed from the driving end of a screwdriver shank comprising a
tubular structure having openings at its opposite ends. The opening
at the forward end is tapered inwardly so that it can be seated
about and centered on the head of a screw, and the circular opening
at the rearward end fits loosely about the shank of a screwdriver
bit. A spring is disposed in the bore of the structure and is held
between its two ends. A clutch member having a ring configuration
is placed between the inward end of the cylindrical structure and
the spring and has a plurality of resilient fingers extending from
its inner surface towards the rearward end to provide a slip clutch
engagement with the shank of the screwdriver bit.
Inventors: |
Wishart; James L. (Louisville,
KY), Blondin; Paul R. (Louisville, KY) |
Assignee: |
Vermont American Corporation
(Louisville, KY)
|
Family
ID: |
25370938 |
Appl.
No.: |
04/877,894 |
Filed: |
November 19, 1969 |
Current U.S.
Class: |
81/451 |
Current CPC
Class: |
B25B
23/101 (20130101); B25B 23/08 (20130101) |
Current International
Class: |
B25B
23/08 (20060101); B25B 23/10 (20060101); B25B
23/02 (20060101); B25b 023/08 () |
Field of
Search: |
;145/5R,5B,5F,5DA,51 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Riordon; Robert C.
Assistant Examiner: Koczo, Jr.; Michael
Claims
We claim:
1. An attachment for use with a screwdriver to guide and hold the
driving end of its shank into engagement with the kerf of a screw
comprising an elongated structure having a bore formed along its
length and having an opening formed in its opposite ends, the
internal surface extending inwardly from one of said ends being
shaped to seat about the head of a screw and the opening in the
other of said ends being sufficiently large to fit loosely about
the shank of the screwdriver, a spring disposed in said bore
extending between said opposite ends, and a clutch member having
means for frictionally gripping the shank disposed between said
spring and said other end, said clutch member having a ring
configuration and said frictional engaging means comprising a
plurality of resilient fingers extending from the inner surface of
said ring configuration towards said other end of said elongated
structure, where the frictional gripping force exerted by said
gripping means against said shank is sufficient to compress said
spring when said one end is seated about a screwhead and the
driving end of the shank is pushed inwardly along said bore towards
the screwhead but will slip upon the application of a substantially
greater inward push on the shank.
2. An attachment for use with a screwdriver to guide and hold the
driving end of its shank into engagement with the kerf of a screw
comprising an elongated tubular structure having a bore formed
along its length and having an opening formed in its opposite ends,
a screwhead-engaging member mounted in the opening in one of said
ends, said engaging member having a cavity which places the opening
in said one end in communication with said bore and which is shaped
to seat about the head of a screw, said cavity having an inwardly
tapered shape and press fitted in said one end of said elongated
structure the opening in said other end being sufficient in size to
fit loosely about the screwdriver shank, a spring disposed in said
bore extending between said other end of said structure and the
inner end of said engaging member, and a clutch member having means
for frictionally gripping the shank disposed between said other end
and said spring, where the frictional gripping force exerted by
said gripping means against said shank is sufficient to compress
said spring when said one end is seated about a screwhead and the
driving end of the shank is pushed along said bore towards the
screwhead but will slip upon the application of a substantially
greater inward push on the shank.
3. The combination of claim 2, wherein said clutch member has a
ring configuration and said frictional engaging means comprises a
plurality of resilient fingers extending from the inner surface of
said ring configuration towards said other end of said elongated
structure.
4. An attachment as defined in claim 2, wherein the inner end of
said screwhead-engaging member abuts against a shoulder portion
formed in said bore at a distance slightly greater than the length
of said screwhead-engaging member, and wherein the outer end of
said screwhead-engaging member abuts against a narrow resilient
annual bead formed about said opening in said one end of said
tubular structure.
Description
BACKGROUND OF THE INVENTION
This invention relates to a screwdriver attachment for guiding the
driving end of a screwdriver shank into engagement with the kerf of
screws and holding it in place therewith.
It is characteristic of screwdriver attachments that they are
permanently mounted on the driving end of the screwdriver shank,
which prevents the user from having the choice of operating the
screwdriver without utilizing the attachment. Also, the permanent
mounting arrangement is objectionable for it would be desirable to
use the same attachment with a multitude of screwdriver bits.
Accordingly, one object of this invention is to provide a
screwdriver attachment which can be selectively removed from the
shank of a screwdriver bit.
Another object of this invention is to provide a screwdriver
attachment which can be used interchangeably with screwdriver
shanks having different cross-sectional shapes.
A further object of this invention is to provide a screwdriver
attachment which can be quickly attached to and removed from the
driving end of the shank of a screwdriver bit by means of a clutch
member which grips the shank in a slip clutch arrangement.
Further objects and advantages of this invention will become
apparent from the following description of the preferred embodiment
and by referring to the drawings illustrating the preferred
embodiment.
SUMMARY OF THE INVENTION
This invention relates to a detachable screwdriver attachment for a
screwdriver bit which functions to guide the driving end of the
shank into driving engagement with the kerf of a screw. The
attachment comprises an elongated tubular structure having a bore
formed along its length and having openings formed in its opposite
ends. Extending inwardly from the opening at the outer end of the
elongated structure is a tapered surface shaped to seat about the
head of a screw. The opening at the rearward end of the structure
is designed to fit loosely about the shank of the screwdriver bit.
A spring is disposed in the bore between the inner and outer ends
of the tubular structure, and a clutch member is positioned between
the rearward end of the structure and the spring. The clutch member
has a plurality of resilient fingers which are adapted to
frictionally engage and grip about the shank with a sufficient
force that the spring is compressed upon the screwdriver shank
being pushed towards the outer end of the cylindrical structure.
The frictional force exerted by the resilient fingers may be
overcome by a pushing or pulling force exerted on the shank which
is substantially greater than the inward pushing force necessary to
compress the spring.
DESCRIPTION OF DRAWINGS
For a better understanding of this invention, reference is made to
the following drawings, in which:
FIG. 1 is a side elevational view of the preferred embodiment of
this invention with its internal parts shown in dotted lines and
with the driving end of the shank of a screwdriver bit being shown
prior to insertion in the inner end of the preferred embodiment and
with the screwhead being shown disposed below the outer end of the
preferred embodiment;
FIG. 2 is a sectional view of the elongated tubular structure;
FIG. 3 is a sectional view of the screwhead engaging member which
fits in the outer end of the elongated structure of FIG. 2;
FIG. 4 is a top plan view of the clutch member which is disposed in
the bore of the elongated structure shown in FIG. 1 between the
inner end of the elongated structure and the spring;
FIG. 5 is a side elevational view of the member of FIG. 4; and
FIG. 6 is a cross-sectional view of the preferred embodiment of
this invention shown with the driving end of a screwdriver shank
inserted through the rearward end of the elongated structure and
held in engagement in the kerf of a screwhead.
DESCRIPTION OF PREFERRED EMBODIMENT
There is shown in FIG. 1, a screwdriver attachment or screwhead
finder 10 which is designed to be quickly mounted on the driving
end 12 of the shank 14 of a screwdriver 16. The screwdriver
attachment 10 is housed in an elongated tubular structure 18 having
a generally cylindrical configuration as best seen in FIG. 2. The
elongated tubular structure 18 is preferably formed as a one-piece
molded plastic part having a knurled portion 20 on its outer
surface to assist the user in gripping the attachment 10. The
elongated tubular structure 18 has a bore 22 along its length and
has circular openings 24 and 26 formed at its opposite ends.
In the outer or forward end 28 of the elongated structure 18, a
screwhead-engaging member 30 (see FIG. 3) is mounted in the outer
portion of the bore 22. The screwhead-engaging member 30 is also
preferably molded plastic material having a cylindrical outer shape
which fits snugly in the outer end 28 between the circular opening
26 and an annular shoulder 32 (see FIG. 2) to hold the member 30
firmly in place. A small annular bead 34 having a diameter slightly
less than the outer diameter of the member 30 is formed about the
opening 26 as clearly seen in FIG. 2. To adapt the
screwhead-engaging member 30 on a variety of screwhead sizes, an
inwardly tapered cavity 36 extends from its outer end 38. Since the
engaging member 30 is press fitted in the elongated structure 18,
it is possible to use a number of engaging members with different
shaped inward cavities with a stock elongated structure 18.
As clearly illustrated in FIGS. 1 and 6, the inner end 40 of the
screwhead-engaging member 30 when inserted in the elongated
structure 18 serves as a stop or retainer for a spring member 42.
The other end of the spring 42 in the stretched condition of FIG. 1
is separated from an annular shoulder 44 by a clutch member 48. The
clutch member 48 has a ring configuration 50 (see FIG. 4) whose
outer diameter is slightly less than the diameter of circular bore
22 to permit it to slide freely along the bore 22. Extending
inwardly from the ring structure 50 is a plurality of equally
spaced resilient fingers 52. These fingers 52 are bent at an
approximate 45.degree. angle to the ring portion 50. When the
clutch member 48 is inserted in the structure 18, the fingers
extend towards the rearward end 46 of the screwdriver attachment
10. With this arrangement, the fingers 52 frictionally engage the
shank 14 of a screwdriver bit 16 with a much greater force when the
shank 14 is inserted inwardly through the bore 22 as compared with
the force applied on the shank 14 when the screwdriver 16 is pulled
out of the attachment 10. This feature is significant for it
permits the shank 14 to be easily removed from engagement with the
attachment 10 but does not sacrifice the gripping force exerted by
the fingers 15 required to hold the spring 42 under compression
during the screwing operation, as illustrated in FIG. 5.
By using the above-described clutch member 48, it is possible to
use the adapter 10 with screwdriver shanks having different
cross-sectional shapes, such as round and hexagonal. All that is
necessary is for the fingers 15 to exert a frictional gripping
force on the shank 14 greater than the force exerted by the spring
member 42 when under compression as shown in FIG. 5. The shank 14
can be readily shifted in position with respect to the elongated
structure 18 by overcoming this frictional force when the shank 14
is inserted into the attachment 10. A very small pulling force on
the shank 14 will remove it from the attachment 10 due to the fact
that the gripping fingers 52 exert a very small frictional force on
the shank 14 in the rearward direction.
In FIG. 6 is an illustration of the intended use for the
screwdriver attachment 10. The lower opening 26 is placed over the
head 60 of a screw 62 until the inner tapered surface 36 of the
screwhead-engaging member 30 is seated firmly about the screwhead
60. Then when a thrust is applied on the bit 16, the shank 14 will
advance against the spring 42 until the driving end 12 engages the
screwhead 60 and the bit 16 is then rotated until it causes the
driving end 12 to index within the slot or kerf 64 in the screwhead
60.
By reason of the foregoing construction of the screwhead finder 10,
it can be seen that this invention discloses a screwdriver
attachment which can be used interchangeably with shanks having
different shapes and with shanks of the same shape but with
different types of driving ends. Further, it is very economical to
manufacture and can be made of most any desired material.
* * * * *