U.S. patent number RE32,614 [Application Number 06/930,683] was granted by the patent office on 1988-03-01 for self-adjusting locking wrench.
This patent grant is currently assigned to Christopher B. Fagan. Invention is credited to Neill R. Wilson.
United States Patent |
RE32,614 |
Wilson |
March 1, 1988 |
Self-adjusting locking wrench
Abstract
A wrench includes an upper jaw integral with a handle and a
force multiplying cam member pivotally mounted on the handle. A
lower jaw has a pivot point for pivoting relative to the cam member
and the upper jaw. A sliding bar is mounted inside the handle to
slide with respect thereto. A free end of a first toggle linkage
member is pivotally connected to an ear of the lower jaw and a free
end of a second toggle linkage member is pivotally connected to the
sliding bar so that the pivot point can move relative to the
handle. A tension spring extends between the ear and the lower jaw
to urge it away from the upper jaw. An extension integral with the
first toggle member forms a second handle coextensive with the
first handle and cooperates therewith to move the jaws toward each
other as the handles are squeezed together. Such movement continues
until the jaws contact an associated object. Continued squeezing of
the handles causes the second toggle member to move the sliding bar
back from the upper jaw. A manually actuated member can rotate the
cam member into contact with the sliding bar thereby inhibiting
further sliding movement thereof. Continued squeezing of the handle
increases the force applied to the pivoted jaw which, in turn,
applies increased rotational force to the cam member as the toggle
members are moved to an over-center position to lock the wrench on
the object.
Inventors: |
Wilson; Neill R. (Berryville,
VA) |
Assignee: |
Fagan; Christopher B.
(Cleveland, OH)
|
Family
ID: |
27033420 |
Appl.
No.: |
06/930,683 |
Filed: |
November 12, 1986 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
443135 |
Nov 19, 1982 |
04499797 |
Feb 19, 1985 |
|
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Current U.S.
Class: |
81/367; 81/375;
81/380 |
Current CPC
Class: |
B25B
7/123 (20130101) |
Current International
Class: |
B25B
7/12 (20060101); B25B 7/00 (20060101); B25B
007/12 () |
Field of
Search: |
;81/367-380 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Meislin; Debra
Attorney, Agent or Firm: Fay, Sharpe, Beall, Fagan, Minnich
& McKee
Claims
What I claim is:
1. A wrench comprising:
a first handle having a fixed upper jaw integral therewith,
a force multiplying cam member pivotally mounted on said
handle,
a movable lower jaw having a pivot point for pivoting against said
cam member to enable said lower jaw to move relative to said cam
member and said upper jaw, said lower jaw also having an ear,
sliding bar means mounted inside said handle and adapted to slide
with respect to said handle,
toggle linkage means including two pivotally interconnected
elongate members, a free end of a first linkage member being
pivotally connected to said ear, a free end .Iadd.of .Iaddend.a
second linkage member being pivotally connected to said sliding bar
means whereby said pivot point is movable relative to said
handle,
a tension spring having one end fixed to said ear and having the
other end operatively connected to said handle whereby said movable
jaw is urged away from said fixed jaw,
an extension integral with said first linkage member, said
extension forming a second handle substantially coextensive with
said first handle and cooperative therewith to move said toggle
linkage means and move said jaws toward each other as said handles
are squeezed together, such movement continuing until said jaws
contact an associated object, and whereby, after such contact,
continued handle squeezing causes the second linkage member to urge
said sliding bar means to move back away from said upper jaw,
and
means operatively connected to said handle for actuating said cam
member to cause said cam member to rotate and contact with
.Iadd.said .Iaddend.sliding bar means and thereby inhibit further
sliding movement thereof, whereby continued squeezing of said
handles increases the force applied to said lower jaw which in turn
applies an increased rotational force through its pivot point to
the cam member which in turn more securely contacts said sliding
bar means and inhibits further rearward movement thereof as said
toggle linkage means are moved to an over-center position to lock
the wrench on the associated object.
2. A locking type wrench comprising:
an elongated first handle provided with an integral fixed upper jaw
at a forward end thereof;
a cam member pivotally mounted on said first handle;
a movable bar adapted to slide against a surface of said first
handle and positioned rearwardly of said upper jaw;
a movable lower jaw cooperable with said upper jaw and pivotable
against said cam member, said upper and lower jaws having opposed
gripping faces adapted to grip an associated object; .[.resilient
means adapted to urge said lower jaw away from said upper
jaw;.].
a second handle pivotally secured to said lower jaw and forming a
first toggle link in a toggle joint;
a second toggle link pivotally engaged at a first end with said
second handle and at a second end with said movable bar, said two
handles being movable toward each other in order to bring said two
jaws into a gripping engagement with said associated object,
continued movement of said handles toward each other causing said
second toggle link to slide said movable bar along said first
handle surface away from said upper jaw; and,
cam actuating means for rotating said cam member with respect to
said first handle while said handles are being moved toward each
other until said cam member contacts said movable bar to prevent it
from sliding further, continued movement of said handles actuating
said toggle joint to an over-center condition to lock the wrench on
said associated object.
3. The wrench of claim .[.2.]. .Iadd.15 .Iaddend.wherein said
resilient means includes a first tension spring connected at a
first end to said lower jaw and at a second end to said cam
member.
4. The wrench of claim 3 wherein said resilient means includes a
second tension spring connected at a first end to said cam member
and at a second end to said movable bar.
5. The wrench of claim 4 wherein a spring .[.rate.]. .Iadd.modulus
.Iaddend.of said second spring is greater than a spring .[.rate.].
.Iadd.modulus .Iaddend.of said first spring.
6. The wrench of claim 3 wherein said lower jaw has a lower ear
section, to which said first tension spring is connected, and an
upper ear section having a convex pivoting surface which cooperates
with a concave surface of said cam member to enable said lower jaw
to pivot against said cam member.
7. The wrench of claim 2 wherein said cam actuating means is
actuatable with the same hand which grips said two handles thus
enabling one hand to control the operation of the wrench.
8. The wrench of claim 7 wherein said cam actuating means is a
lever which is pivotally secured to said first handle member.
9. The wrench of claim 8 wherein said lever contacts and urges
downwardly an upward projection of said cam member, said upward
projection extending through an aperture in an upper surface of
said first handle.
10. The wrench of claim 2 wherein said toggle link can adjust the
location of said first and second .[.handle.]. .Iadd.handles
.Iaddend.and hence said upper and lower jaws so that associated
objects of various sizes can be gripped.
11. The wrench of claim 2 wherein the degree of clamping force
applied to said associated object is dependent on when said cam
actuating means is operated to rotate said cam member during the
movement of said movable bar to stop the movement thereof.
12. The wrench of claim 2 wherein said cam member is pivotally
mounted on stud means secured to said first handle.
13. The wrench of claim 12 wherein said stud means includes:
a threaded stud having a convex upper surface which cooperates with
a concave surface on said cam member; and,
a nut secured to said first handle, said stud being threaded in
said nut.
14. The wrench of claim 13 wherein said stud can be adjusted in
said nut to allow adjustment of a point of pivoting of said cam
member on said first handle thereby allowing a take-up for wear in
.[.the several elements.]. .Iadd.said cam member, said movable bar,
said second toggle link and said cam actuating means .Iaddend.of
the wrench. .Iadd.
15. The wrench of claim 2 further comprising resilient means
adapted to urge the lower jaw away from the upper jaw..Iaddend.
.Iadd.16. The wrench of claim 2 wherein said cam member is spaced
from said movable bar until acted on by said cam actuating
means..Iaddend. .Iadd.17. The wrench of claim 2 further comprising
a pivot means, secured to said first handle, for enabling said cam
memer to pivot in relation to said first
handle..Iaddend. .Iadd.18. A locking type wrench adapted for
one-handed operation comprising:
an elongated first handle provided with a fixed upper jaw at a
forward end thereof and a handle body including a top wall and a
pair of opposed side walls;
a pivotable bar pivotally mounted on said first handle;
a slidable bar held in said handle body and adapted to slide
against said first handle body top wall, said bar being positioned
rearwardly of said upper jaw;
a movable lower jaw which is adapted to cooperate with said upper
jaw, said upper and lower jaws having opposed gripping faces
adapted to grip an associated object;
an interaction means for contacting said lower jaw with said
pivotable bar to cause a movement of said lower jaw when said
pivotable bar is pivoted;
a second handle pivotally secured to said lower jaw and forming a
first toggle link in a toggle joint;
a second toggle link pivotally engaged at a first end with said
second handle and at a second end with said movable bar, said two
handles being slidable toward each other in order to bring said two
jaws into gripping engagement with the associated object, and
wherein movement of said handles toward each other causes said
second toggle link to slide said movable bar along said first
handle body top wall away from said upper jaw; and,
manually operated pivotable bar actuating means for rotating said
pivotable bar with respect to said first handle while said handles
are being moved toward each other, continued rotation of said
pivotable bar by said pivotable bar actuating means causing said
pivotable bar to engage said slidable bar and prevent any further
sliding thereof, continued movement of said handles after said
pivotable bar engages said slidable bar actuating said toggle joint
to an over-center condition to lock the wrench
on the associated object..Iaddend. .Iadd.19. The wrench of claim 18
further comprising a pivot member secured to said first handle to
enable said pivotable bar to pivot around said pivot
member..Iaddend.
Description
.Iadd.This application is a reissue of U.S. Pat. No. 4,499,797
which issued on Feb. 19, 1985..Iaddend.
BACKGROUND AND SUMMARY OF THE INVENTION
This invention is directed to a wrench of the locking type which
will grip objects of various sizes and hold these objects without
the necessity of the wrench operator constantly applying force to
the handles of the wrench. An over-center toggle type linkage is
used to hold a lower pivoted jaw relative to an upper fixed
jaw.
The primary object of this invention is to provide a wrench that
automatically self-adjusts itself to various size objects. The
wrench operator does not have to adjust a screw or other adjustment
means before gripping an object.
Another object of this invention is to provide a wrench that in
addition to self-adjusting to various sizes is also capable of
gripping objects with a wide variation in clamping force. The
degree of force applied to an object is controlled each time the
wrench is closed or used by merely applying pressure on a special
force control lever provided on the wrench.
Yet another object of this invention is to provide a wrench that
lends itself to one hand operation. In one variation the wrench is
provided with a force control lever on the top forward part of the
upper handle, where it can be operated with ones thumb, while the
wrench handles are closed by using ones hand and fingers. In
standard manually adjusted wrenches of this type (A well-known
brand or trade name of these standard wrenches is Vice-Grip.), the
adjustment screw must be adjusted and often re-adjusted prior to
use, and/or the adjustment screw must be turned with one hand while
some force is applied to the wrench handles with the other hand to
thereby arrive at a reasonable adjustment. In many circumstances
(such as when parts must be held) this type of manual adjustment is
very difficult or impossible.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the pliers or wrench of the
present invention will be apparent from the following detailed
description taken in connection with the accompanying drawing in
which:
FIG. 1 is an elevational view of the wrench in section to more
clearly illustrate the same and showing the pliers or wrench with
jaws thereof locked.
FIG. 2 is an elevational view of the upper handle 10 in section
with attached fixed jaw 11 and attached nut 42.
FIG. 3 is a sectional view of an intermediate portion of the
assembled wrench with sliding bar therein as shown in FIG. 1.
FIG. 4 is an elevational view of the movable jaw 13 as it would
appear removed from the wrench.
FIG. 5 is an elevational view of the cam bar 31 as it would appear
removed from the wrench.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The wrench of the present invention, referring now to the drawings,
comprises a lever 10 forming a handle for a jaw 11 which due to the
normal action of the wrench will be hereinafter referred to as the
fixed jaw. The lever 10 may be formed of some suitable metal in any
member desired but as clearly shown in FIG. 3 is channel-shaped
throughout its intermediate portion as well as at the end carrying
the jaw.
The jaw 11 is faced with a hard metal plate 12 provided with teeth
or serrations along the work engaging face thereof. The plate
forming the work engaging element 12 is welded or otherwise
permanently fixed to the jaw 11.
The movable jaw 13 of the wrench comprises a drop forging or
similarly formed member. This jaw is pivotally attached to the
forward end of cam bar 31 by means of a cylindrical pivot surface
36 formed on the jaw which interfits with a cylindrical cut 32
formed in the end of cam bar 31. Jaw 13 is retained in pivotal
relation with cam bar 31 when the wrench is assembled by means of
the additional cylindrical surface 37 provided on the jaw. Surface
37 is concentric with surface 36 and is formed with a radius that
permits it to just clear the inside surface 28 of fixed jaw 11. The
free end of jaw 13 has a hardened work engaging serrated face that
cooperates with face 12 on fixed jaw 11 to grip objects.
As stated above a portion of movable jaw 13 is retained inside of
handle 10 by being retained between cam bar 31 and the inside
surface 28 of fixed jaw 11. Cam bar 31 is in turn pivotally
retained inside of handle 10 by means of a cylindrical surface 38
provided by the lower edge of bar 31, wherein surface 38 interfits
with the spherical head 39 provided on threaded stud 41. Stud 41 is
threaded into a nut 42 that is welded to the inside surface or
surfaces of handle 10. The provision of this threaded stud 41
allows the pivot point between cam bar 31 and handle 10 to be
adjustable to take up for wear in various parts. An interference
fit is provided within the threads of stud 41 to prevent unwanted
movement of the stud.
In addition to cam bar 31, a sliding bar 51 is positioned inside of
handle 10. Sliding bar 51 has an elongated forward end which slides
in above cam bar 31 and is thereby sandwiched between the cam bar
and the top inside surface of handle 10. Sliding bar 51 has a
channel shaped back end 52 which interfits with the other end of
toggle link 17. Pivot pin 54 provides a permanent pivotal
connection between bar 51 and link 17. A tension spring 57 is
provided between sliding bar 51 and the outer or back end of cam
bar 31 which tends to pull and maintain sliding bar 51 into a
forward position.
The movable jaw 13 is actuated by means of two over-center type
toggle links. One link is actually a lever 16 pivotally connected
by a pin, at one end thereof to an ear 14 formed integral with the
jaw 13 and at its opposite end (once again by a pivot pin) to the
lower end of the other link 17 of the two toggle links. The lever
16 is formed with an extension 16a which serves as a handle member.
Handle 16a is used in conjunction with upper handle 10 to operate
the tool. The second link 17 is pivotally connected to link or
lever 16 intermediate the ends thereof by pivot pin 18 and
therefore the two links as operated by the handle end 16a of link
16 to form a toggle linkage which rotates movable jaw 13 in a
clockwise direction (as shown in FIG. 1) as handle 16a is squeezed
upwardly toward handle 10 by the tool operator. When handle 16a is
forced downwardly to open the wrench, movable jaw 13 will rotate in
a counterclockwise direction (about pivot surface 36) to thereby
open the jaws. Jaw 13 is caused to rotate and thereby open due to
the provision of tension spring 58 which extends from the ear
portion of jaw 13 up to an anchor point on handle 10 or an anchor
point on cam bar 31 (as shown in FIG. 1).
In operation of this wrench the operator must first flick down
handle (lever) 16a relative to handle 10. This action allows
movable jaw 13 to rotate counterclockwise (due to pull exerted by
spring 58) whereby the jaws are opened. Next the object to be
gripped is placed between the jaws and one hand is used to squeeze
handle 16a upwardly toward handle 10. This squeezing action rotates
movable jaw 13 in a clockwise direction until the object being
gripped is contacted and forced against fixed jaw 11. At this point
the operator continues to squeeze handle 16a toward handle 10
thereby forcing the toggle links more toward their closed position.
Since jaw 13 has essentially stopped, the upper end of toggle link
17 must move back relative to handle 10. Continued squeezing
thereby forces sliding bar 51 to move back relative to handle 10,
because it is pivoted to the upper end of link 17.
At this point in operation it is desirable to apply added force to
the object being gripped and in order to do this the rearward
sliding movement of sliding bar 51 must be braked or inhibited.
Cam bar 31 is provided to cam against and brake the rearward
movement of sliding bar 51. Cam bar 31 is provided on its upper
surface with a camming surface 33 which rubs against the lower
surface of sliding bar 51. When cam bar 31 is rotated or rocked a
slight amount in a counterclockwise direction about its pivot
surface 38, the camming surface 33 is forced up against the bottom
surface of sliding bar 51, whereby bar 51 is gripped between
camming surface 33 and the inside of handle 10.
Manual means [which includes the upstanding projection 35 (on cam
bar 31) and the thumb lever 61 provided on the top handle 10], are
provided to exert an initial force on the cam bar at any desired
instant in the operation of the tool. At the point in closing or
squeezing of the handle when it is desired to brake movement of
sliding bar 51 and thereby apply force on the object being gripped,
the operator applies a downward force on lever 61 with his thumb.
This action in turn forces down the forward end of cam bar 31 a
slight amount thereby rotating bar 31 a slight amount. Cam surface
33 (on bar 31) is thereby forced up against and brakes the rearward
movement of sliding bar 51. This initial braking of sliding bar 51
then sets up a chain reaction in the wrench. This occurs because as
the operator squeezes the toggle links more toward their
over-center position more force is applied to movable jaw 13 by
link 16. This additional force tends to rotate jaw 13 about an axis
extending through its point of contact with the object being
gripped. Very little movement actually occurs, but the little that
does occur urges the pivot surface 36, on jaw 13 downwardly against
the forward end of cam bar 31 with a great deal of force. This
additional force on bar 31 thereby forces camming surface 33 (on
bar 31) up against the sliding bar 51 even more to thereby stop all
rearward movement of bar 51.
The toggle links are thereafter forced on to their over-center
position and the wrench is in a locked state.
In order for this tool to operate properly, the spring .[.rate.].
.Iadd.modulus .Iaddend.of spring 57 must be selected to be greater
than the .[.rate.]. .Iadd.modulus .Iaddend.of spring 58 (e.g., the
jaw must move to a closed position before the sliding bar begins to
move back).
In actual operation, the lock up force exerted by the jaws is
determined each time the tool is used by the point at which an
operator applies a force on lever 61. By this I mean that sometime
during closing or squeezing of handles 16a and 10 the operator will
apply a force with his thumb on lever 61 and the selection of time
during closing and degree of force applied to lever 61 will
determine the lock up force applied. A few trial operations of the
tool will provide any operator with a feel for the operation of the
tool.
Although the now preferred embodiment of the present invention has
been shown and described herein it is to be understood that the
invention is not to be limited thereto for it is susceptible to
changes in form and detail within the scope of the appended claim.
For instance the force control lever 61 could be modified and
placed on or pivoted on link 17 (rather than on top of the tool) in
such a manner that force could be applied to the lower surface of
the back end of cam bar 31 to in turn press cam surface 33 up
against the sliding bar. This structure may have merit because the
force control lever could also double as a wrench release or
unlocking lever. Release or unlocking levers of this type are shown
in U.S. Pat. No. 2,574,676 and are currently used on the locking
wrenches or pliers being sold by Sears, Roebuck & Co.
The invention have been described with reference to a preferred
embodiment. Obviously, modifications and alterations will occur to
others upon the reading and understanding of this specification. It
is intended to include all such modifications and alterations
insofar as they come within the scope of the appended claims or the
equivalents thereof.
* * * * *