Improved Method of Releasing Locked Instruments, applicable to Pocket Knives and the like.
Year: 1898

page_text: Date of Application, 17th Feb., 1898-Accepted, 20th May, 1898
Improved Method of Releasing Locked Instruments, applicable to
Pocket Knives and the like.
We, EDMUND PRIESTMAN, and FRED NELL, and FREDERICK THORNHILL, all of
Sheaf Island Works, Pond Hill, Sheffield, Cutlery Manufacturer, and Cutlers,
do hereby declare the nature of this invention and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement:-
_
Heretofore the locking arrangements for blades of knives and the like instru-
ments have been effected by means of spring actuated catches, such springs
operating only to close the parts and to keep the same closed automatically; To
release such blades a complex operation is necessary, and usually the abutment
against which the locking spring acts is first removed, and a spring or lever has
to be depressed separately to raise the catch out of the locking notch and thereby
permit the blade to be folded or closed.
The object of our invention is to effect by one single movement both the
removal of the abutment and also the necessary depression of spring or lever.
To carry our invention into effect for say a pocket knife, we take a knife of any
well known form or construction, but preferably a knife containing two blades,
or one blade and some other ordinary instrument such as a hook or a screw-driver,
fitted into the opposite ends of the handle, the spring running along inside
handle at the back of both implements is fixed or held in position by one rivet
acting as a pivot placed out of the centre and nearer to the rear end; The end
of the spring pressing upon the blade to be locked has the usual notch, pin, or
projection to engage the corresponding parts of the blade, the opposite or rear
end likewise presses upon and also is made to enter into a notch or slot formed in
the butt end of the blunt implement, which, although pivotted in the usual
manner, is only capable of being moved to a limited extent, the motion itself
being backward, i.e., the reverse way of ordinary blades; The result of such
reverse motion is that the end of the spring is depressed, and consequently its
opposite end is elevated clear of the locking device, leaving the blade free to
move, whereupon all the parts simultaneously resume their normal positions and
operations. This construction of parts also enable us to use much longer blades
than can be put into handles fitted with revolving or removable abutments.
When it is desirable however to effect the releasing of the blade by folding
abutments of the last named class for which see example Fig. 3, having little or
no projection beyond the end of the knife handle, we fix an additional spring
inside of handle so as to press the back spring outwardly at the locking end
automatically so soon as the abutment is moved without any other operation.
This extra spring we form out of sheet steel with side projections to keep it
firmly in position.
And now that our invention may be better understood we will further explain
the came by reference to the drawings annexed hereto, wherein, Fig. 1 repre-

page_text: sents an open pocket-knife, (the outer scale or half of handle being removed in
all the figures) the blade being locked and all the parts shown in proper positions.
Fig. 2 shows the same with the blade closed.
Fig. 3 illustrates the application of our auxiliary spring as having pushed
the locking device apart and so allowed the blade to be partially closed. Fig. 4
is a flat view of auxiliary spring.
The same letters refer to like parts in all the figures, i.e.-A is the handle,
B, the blade to be released, C, the back spring pivotted upon C and operating
the locking device, D, is a screw-driver or other blunt instrument projecting
beyond the end of handle and having a slot S, formed in its butt end to receive
the end of the back spring C, movement takes place around D¹ as a pivot in the
direction of the arrow. E, is an auxiliary spring operating to push the back
spring C, clear of the locking device so soon as the customary abutment D2 has
been moved from the end to the side as shown in Fig. 3. '
Having now' particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed; we declare that what we
claim is:-
1st. In a pocket-knife or the like instrument having a device for locking the
blade in an open position, the addition to and combination therewith of a blunt
instrument having a slot formed in its butt end to receive one end of the back
spring or lever operating the locking device in such manner that whenever the
said blunt instrument is pressed backward, the elements of the locking device
will be freed, substantially as herein described and illustrated.
2nd. In a pocket-knife or the like instrument having a device for locking the
blade in an open position, the addition to and combination therewith of an
auxiliary steel spring to push apart automatically the elements of the locking
device whenever the abutment has been moved clear of the spring or lever, sub-
stantially as herein described and illustrated.
Dated this 16th day of Fehmi 1908
ISAAC BECK, F.S.P.A.,
Agent for the Applicants, Haymarket Chambers, 17, Haymarket, Sheffield.