Improvements in Knives and Detachable Handles therefor.
Year: 1890

page_text: Date of Application, 27th Dec., 1890--Accepted, 28th Feb. 1891
COMPLETE SPECIFICATION.
Improvements in Knives and Detachable Handles therefor.
1, JAMES JOHNSTON, of Bradford, McKean County, State of Pennsylvania,
United States of America, Inventor, 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 :-
My invention relates to an improvement in knives and detachable handles therefor,
and it consists in the combination of a handle provided with an extension on its
inner end and a bead or flange which extends across the end of this extension, and
having a flange in order to prevent the blade from having any lateral play, with
the blade having a transverse groove to receive the flange or bead at some distance
from its end, and a groove in its end to receive the flange which prevents lateral
play, as will be more fully described hereinafter.
The object of my invention is to especially provide surgical knives with detachable
handles and which handles are adapted to be applied to a number of different
blades, and which handles when detached from the blades, allow every portion of
the blade to be thoroughly dried and cleaned after having been boiled, and thus
preventing any part from being exposed to rust.
Fig. 1 is a side elevation of a handle, to which a blade is applied.
Fig. 2 is a perspective of a handle alone.
Fig. 3 is a perspective of a blade alone.
A represents the handle which is made of metal and which is provided with the
extension B of any suitable length and which has a bead or flange C formed across
the inner side of its outer end. This extension is quite thin but is as wide as the
handle and its flat inner face forms a surface against which a corresponding surface
upon the knife is made to bear.
At the inner end of this extension is formed an abrupt shoulder D which is
concaved or rounded out next to the extension and at the centre of this shoulder
is formed the flange G which serves to prevent the blade from having any lateral
play.
The blade H is provided with a thickened end I and extending across near
the inner end of this thickened portion I is the transverse groove J in which
the bead or flange C upon the handle catches for the purpose of holding the
two parts in contact with each other. This bead or flange should first be
inserted in the transverse groove while the two parts are held at a slight angle
to each other, and then the two parts are straightened in a line with each
other. The Hat inner surface of this thickened portion form as a bearing
against which the extension B rests and in the extreme outer end of the
thickened part I is formed the groove O which receives the flange G for the
purpose of locking the two parts in a line with each other.
In order to separate the two parts, it is only necessary to hold the blade in
one hand while an outward pressure is applied to the handle, and this pressure
first forces the flange G out of the groove O and then the transverse flange or
bead readily separates from the groove in which it fits.
By means of my invention an improved means of detachably fitting to a handle
different blades or similar instruments is provided and whereby one handle may
answer for a number of different instruments. The handle and blade can be
quickly secured together and readily detached and either or both parts be boiled
and thoroughly cleaned without any part being inaccessible and thus exposed to
rust.
All pins, screws, ratchet-wheels, catches, and springs of any description are

page_text: done away with as being too troublesome and inaccessible and hence are exposed
to rust after having been exposed to moisture.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
.claim is :-
:-
1. The combination with the handle having on its inner end an extension which
has a curved shoulder at each of its ends, of a blade having an enlarged inner
end which fits between and is engaged by the said shoulders on the handle,
substantially as shown.
2. The combination of the handle provided with an extension upon its end, a
transverse bead or flange at the end of the extension, and a second flange for
preventing lateral movement, with the blade having a transverse groove to receive
the bead or flange and a groove in its end to receive the flange which prevents
lateral movement, substantially as shown.
Dated thin 27th Dansmbar 1800
JENSEN & SON,
77, Chancery Lane, London, W.C., Agents for the Applicant.