Volume 8, Issue 2 - November 2013
Over the last few years, any mention of the word espionage sends
the press into a fury of activity over the practice used by
government agencies under the guise of protecting sovereign
interests. For the industrial world, it is a given that someone
will always try to steal any fresh concept and market it for
profit while maintaining much secrecy. In some cases, it is
outright theft, and the perpetrator banks on the fact that there
is a window of opportunity before the original manufacturer
can or does mount a defense to stop this encroachment. As a
companion piece to the "From the Collection" article,
we offer up an "Interesting Patent" item that is very
similar to but slightly different from the original and was
outside any retaliation from the originator.
First the concept of a patent: Not wanting to arouse the ire
of those who work in this field, we shall just state a very
basic path. One thinks of a product, one makes a prototype (or
not), one registers the idea with the appropriate country's
patent agency, one manufactures the product and reaps the benefits
(or not) of the new idea. It can be a long and arduous path.
There are often fixed limits on how long a patent can be protected,
and there are strong rules regarding replicating a patented
item without making significant changes to an original concept.
Protection has varied from 5, 12, 14 and 17 years. As of 2013,
there is now a 20-year protection period internationally. Any
litigation, however, is extremely costly and takes an inordinate
amount of time. In some cases, the final costs can be more than
the anticipated profits of selling the item.
pliers were the invention of William Peterson in 1921, with
the locking-lever concept granted in 1924. By 1941, the original
patent expired, and competitors started manufacturing their
own concept of the locking pliers without violating the original
Peterson patent. A subsequent patent in 1940 did nothing to
stop the competition.
Ernest J. St. Laurence of Minneapolis, Minnesota, sought with
patent #2,489,057, dated November 22, 1949, to improve the mechanical
fixation for the jaws of locking pliers. With his design, he
also allowed for a sliding movable lower jaw, thereby creating
a better gripping action. St. Laurence's claim cites the earlier
patent (#2,285,683), in which there were issues with the retaining
pins in the insert jaws during usage. These pliers were manufactured
under the name Pli-Rench, and the pictures show a sliding bottom
jaw that maintained a parallel face throughout most of the tool's
A further word about copying: The Internet has done much to
spread ideas and processes around the world. It is perfectly
all right, I think, to replicate a product for one's personal
use in a non-commercial venue. Making two, however, and selling
one, or perhaps enabling others to copy it by publishing a version
of a patented copy is a violation of the patent act.
D.S. Orr has been a collector, user and student of woodworking
and metalworking tools and practices for more than 40 years.
Recently retired, he has devoted even more time to these endeavors.
States Patent Office
LEVER OPERATED GRIPPING TOOL WITH SLIDABLE JAW FACE
Ernest J. St. Laurence, Minneapolis, Minn.
Application September 20, 1945, Serial No. 617,646
Patented Nov. 22, 1949
present invention relates to an improvement in hand-operated
gripping tools such as pliers or wrenches of the type incorporating
cooperating gripping jaws, one of which has a moveable gripping
surface mounted for arcuate movements with respect to the cooperating
gripping surface of the other jaw. In tools of this type the
circumferentially shiftable gripping element of a gripping jaw
is provided with segmental bearing surfaces that seat on corresponding
segmental seats in the cooperating jaw and the shiftable gripping
element is usually retained against accidental displacement
by an arcuate slot and pin connection between the gripping jaw
element and the cooperating jaw element, one such arrangement
being shown in the Seashore Patent 2,285,683 of June 9, 1942.
In tools of the above described type, the retaining pin, referred
to, is often accidentally sheared off by stresses placed thereon
in service; and this invention is directed particularly to means
for preventing this accidental shearing of the retaining pin
when stresses applied to the tool tend to move the shiftable
jaw element beyond the extreme limit permitted by engagement
of one end of the slot with the cooperating retaining pin.
The above and other highly important objects and advantages
of the invention will be made apparent from the following specification,
claims, and appended drawings.
In the accompanying drawings, like characters indicate like
parts throughout the several views.
Referring to the drawings:
Fig. 1 is a longitudinal sectional view through a tool incorporating
the invention, with some parts on the sectional line shown in
Fig. 2 is an enlarged fragmentary view of the tool shown in
Fig. 1, but showing a somewhat different position of the parts;
Fig. 3 is a front end view of the tool of Fig. 1 taken on the
line 3-3 of Fig. 1; and
Fig. 4 is a transverse sectional view taken on the line 4-4
of Fig. 1.
The tool illustrated, and in connection with which a preferred
form of the invention is herein illustrated, is of the general
character shown in the said Seashore Patent 2,285,683 and comprises
a relatively fixed handle element 5, formed integrally with
a relatively fixed or rather relatively stationary gripping
jaw 6, a cooperating relatively moveable gripping jaw 7, that
is pivotally anchored to the fixed jaw 6 at 8, an operating
lever 9 pivoted to the movable jaw 7 at 10, and a toggle link
11 pivoted at one end to the lever 9 at 12 and having its other
end slidable in the handle 5. The rear end of the toggle link
11 works slidably in a slot 13 and the handle 5 is retained
against accidental displacement therefrom by a head acting pin
14, and reacts against a screw threaded adjustment screw 15.
The toggle link 11 at its intermediate portion is provided with
a depending stop lug 16 that engages the lever 9 when the toggle
link 11 is moved just past dead center in a jaw closing direction.
The jaw 7 is biased to move pivotally in a jaw opening position
by means of a coil tension spring 17. The fixed jaw 6 is provided
with a fixed gripping element in the nature of a toothed gripping
plate 61 that may be assumed to be welded or otherwise rigidly
Preferably and as illustrated herein the movable jaw element
7 is formed of a cooperating pair of sheet metal plates 18 that
are riveted or otherwise rigidly secured as at 19. These jaw
plates 18 are spread apart beyond their intermediate portions
to provide a pair of laterally spaced jaw flanges 20. In accordance
with the invention the upper surfaces of these jaw flanges 20
are formed to provide concave seats 21 to receive convex bearing
surfaces on shoulders 22 of a shiftable or movable toothed gripping
element 23 for the jaw 7. The shiftable gripping element 23
is provided, intermediate the convex bearing surfaces 22, with
a downwardly projecting guide flange 24 that works between the
laterally spaced jaw flanges 20. The moveable jaw element 23
is held against accidental displacement from the cooperating
jaw 7 by slot and pin connection comprising a segmental slot
25 in the guide flange 24 and a cooperating guide pin 26 extending
through the spaced jaw flanges 20 and the slot 25.
Circumferential or arcuate movements of the shiftable jaw element
23 are limited in one direction by engagement thereof with the
fixed jaw 6, as shown in Fig. 1, or by coincidental engagement
of the pin 26 with the outer end of the segmental slot 25.
In prior art, tools having sliding jaws of the type described,
outward circumferential or arcuate movements of the sliding
jaw have been limited solely by engagement of the guide pin
with the opposite or inner end of the arcuate slot and tend,
under conditions such as shown in Fig. 2, to shear off the guide
pin. In Fig. 2, the tool is shown as gripping a pipe A between
the inner portions of its gripping surfaces, which tends to
force the shiftable jaw element 23 beyond the normal limit permitted
by engagement of the pin 26 with the end of the slot 25 and,
of course, this tendency is greatly increased when the tool
is turned in a counter-clockwise direction with respect to Fig.
2. In the present tool, however, this tendency is eliminated
or greatly reduced by provision on the guide flange 24 of a
stop lug or projection 27 with a cooperating stop pin 28 extending
through and between the jaw flanges 20. The pin 28 is so oriented
as to be engaged by the stop lug 27 either just prior to or
coincidentally with engagement of the pin 26 with the inner
end of slot 25. The pin 28 can be heavier and stronger than
is normally used for cooperation in the slot 25.
What I claim is:
In a gripping tool having cooperating jaws mounted for relative
movement, one of said jaws having a relatively fixed gripping
surface and the other jaw being provided with an arcuately shiftable
gripping element for cooperation with the relatively fixed gripping
surface of the first named jaw, said second named jaw comprising
laterally spaced parallel flanges provided with concave seats,
said shiftable gripping element having a plane guide flange
projecting therefrom and freely extending into the space between
said jaw flanges and said gripping element having convex shoulders
on opposite sides of the guide flange seated on said concave
seats, an arcuate slot and pin connection between the guide
flange and the jaw flanges for maintaining said convex shoulders
in seating engagement with said concave seats and for limiting
movement of the gripping element in an outward direction, said
guide flange being provided with a stop lug projecting therefrom
in a direction away from said griping element, and a stop pin
carried by the jaw flanges and extending across the space therebetween,
said pin being disposed beneath said guide flange and in the
path of movement of said stop lug for engagement thereby substantially
coincidentally with the engagement of the first named pin with
an end of its cooperating arcuate slot upon movement of said
gripping element in an outward direction, whereby to prevent
shearing of the first named pin.
J. ST. LAURENCE.
following references are of record in the file of this patent:
||Feb. 15, 1910
||Dec. 24, 1912
||Mar. 18, 1930
||June 9, 1942