An Improved Joint for the Detachable Parts of Mathematical or Drawing Instruments, and for other purposes.
Year: 1890

page_text: Date of Application, 23rd Aug., 1890
Complete Specification Left, 15th May, 1891-Accepted, 11th July, 1891
PROVISIONAL SPECIFICATION.
An Improved Joint for the Detachable Parts of Mathematical or
Drawing Instruments, and for other purposes.
We, WILLIAM JOSEPH HARRIS, of 33 & 34, Cardigan Street, in the City of
Birmingham, Mathematical Instrument Manufacturer, and WILLIAM OVERTON,
of 15, Goodrick Street, Birmingham, aforesaid, Mathematical Instrument Maker,
do hereby declare the nature of this invention to be as follows:-
This invention has reference to an improved joint for removably securing
together the detachable parts of mathematical or drawing instruments and the said
joint is also applicable for other purposes such as for removably securing any one
of a set of surgical or other instruments or tools in a handle common to the set.
The said improved joint is of that kind which is technically known as a
"slip-up" joint one of the parts having a parallel shank or spigot which fits into a
parallel socket in the other part.
Heretofore in this kind of joint the said spigot and the socket in which the spigot
fits have usually been made round, the socket being slotted longitudinally at one
side and the spigot having a feather fitting in the slot to prevent the spigot part
turning. The fitting of the said feather is comparatively expensive and the object
of this invention is to construct a reliable "slip-up" joint in which a feather is not
required.
In carrying out this invention the said spigot and the socket in which it fits are
made parallel as heretofore and the socket has either one or more longitudinal slots
or divisions or it may be left solid. The spigot part is prevented from turning in
the socket by the spigot and socket being made somewhat of the shape of the
letter D in cross section or for this purpose they may be made square triangular or
of other form. The object of slotting or dividing the socket part as above
described is to enable it to expand slightly when the spigot part is inserted therein
and thus to fit the spigot part more tightly and allow for wear.
Dated this 22nd day of August 1890.
CHARLES BOSWORTH KETLEY,
Agent for the Applicants.
COMPLETE SPECIFICATION.
An Improved Joint for the Detachable Parts of Mathematical or
Drawing Instruments, and for other purposes.
We, WILLIAM JOSEPH HARRIS, of 91 Shadwell Street, late of 33 & 34 Cardigan
Street, both in the City of Birmingham, Mathematical Instrument Manufacturer,
and WILLIAM OVERTON, of 15 Goodrick Street, Birmingham, aforesaid,
Mathematical Instrument Maker, 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 :-
This invention has reference to an improved joint for removably securing
together the detachable parts of mathematical or drawing instruments and the said
joint is also applicable for other purposes such as for removably securing any one
of a set of surgical or other instruments or tools in a handle common to the set.
The said improved joint is of that kind which is technically known as a
"slip-up" joint one of the parts having a parallel shank or spigot which fits into a
parallel socket in the other part.
Heretofore in this kind of joint the said spigot and the socket in which the

page_text: spigot fits have usually been made round, the socket being slotted longitudinally at
one side and the spigot having a feather fitting in the slot to prevent the spigot
part turning. The fitting of the said feather is comparatively expensive and the
object of this: invention is to construct a reliable "slip-up" joint in which a feather
is not required.
We will describe our invention by referring to the accompanying drawing on
which
Fig. 1 represents on an enlarged scale in elevation and in cross section the socket
end, and
Fig. 2 represents in elevation and in cross section the spigot end of a pair of
compasses constructed according to this invention;
Fig. 3 is also an elevation of the said spigot and looking from the opposite side
to that shewn in Fig. 2;
Figs. 4 and 5 illustrate in cross section a modified form of the said spigot and
socket respectively;
Figs. 6 and 7 are similar views of a further modification and
Figs. 8 and 9 are similar views of a further modification.
The same letters of reference indicate the same or corresponding parts in all the
figures of the drawing.
In carrying out this invention the spigot A and the socket B in which the spigot
fits are made parallel as heretofore and the socket B has either one or more longi-
tudinal slots or divisions b or it may be left solid. The spigot part A is made a
good fit in the socket B and prevented from turning therein by the spigot and
socket being made somewhat of the shape of the letter D in cross section, see Figs. I,
2 and 3; or for this purpose the spigot and socket may be made triangular (Figs. 4
and 5) or square (Figs. 6 and 7) or pentagonal (Figs. 8 and 9) in cross section or
of any other suitable form with one or more flat sides to prevent the spigot part
turning round in the socket without the use of a feather on the spigot part.
When the spigot A is inserted in the socket B the latter is thereby slightly
expanded and caused to clip the spigot A and hold the same securely without any
feather or set screw being used. The slotting or dividing of the socket part also
allows for wear therein and on the spigot.
Our invention as above described can be similarly applied to securing any one of
a set of surgical or other instruments or tools in a handle common to the set.
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 :-
The improved "slip-up" joint for the detachable parts of mathematical or
drawing instruments and for removably securing any one of a set of surgical or
other instruments or tools in a handle common to the set, herein before described
and illustrated by the accompanying drawing, that is to say, the combination of the
spigot A and the socket B made of either of the shapes hereinbefore described and
represented so as to fit securely together and the spigot be prevented from turning
in the socket without the use of a feather or set screw substantially as hereinbefore
set forth.
Dated this 14th day of May 1891.
CHARLES BOSWORTH KETLEY,
Agent for the Applicants.