Improvements in Drawing Compasses.
Year: 1897

page_text: Improvements in Drawing Compasses.
I, FRANK HENRY SHAW, of Newhall Hill, in the City of Birmingham, Manu-
facturer, do hereby declare the nature of this invention to be as follows:-
This invention relates to the joints of drawing compasses, and has for its object,
a simple and efficient means of tightening up the pin or screw passing through
the head and forming the pivot upon which the legs of the compass turn.
Heretofore, the rivets or centres of compass joints have been provided with
sunken heads, or with caps which are rotated or screwed home more or less in order
to give the joints the necessary stiffness and to compensate for wear.
My improved adjustable joint consists of a bifurcated end of one leg fitting upon
a tongue or plate end of the other leg, with a screw pin passing through plain
coincident holes in the joint ends of both legs, one end of the said pin preferably
having a large nicked head, with the plain face abutting against the cheek of one
of the branches of the bifurcated end, whilst the other end is wormed and takes a
preferably hardened steel nut, whose inner side comes co-adjacent to or bears
against the outer face or branch of the bifurcated joint end.
By simply screwing up the nut on the end of the pin by a spanner, key or pair
of pliers the necessary stiffness is given to the joint and any wear is compensated
for.
The edges of the nut are preferably facetted or made square, hexagonal or of
other figure to facilitate the holding of the same whilst the screw is being rotated.
for tightening up, and instead of having a head at one end of the cross pin, both
ends of the same may be screwed and be fitted with steel nuts.
נ..
£1007
I, FRANK HENRY SHAW, of Newhall Hill, in the City of Birmingham, Manu-
facturer, 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 relates to the joints of drawing compasses, and has for its object,
a simple and efficient means of tightening up the pin or screw passing through
the head and forming the pivot upon which the legs of the compass turn.

page_text: Heretofore, the rivets or centres of compass joints have been provided with
sunken heads, or with caps which are rotated or screwed home more or less in order
to give the joints the necessary stiffness and to compensate for wear.
Figures 1 and 2 represent elevations of the two opposite sides of a compass pro-
vided with my improved adjustable joint.
Figure 3 is a vertical section of the same upon the dotted line x.
Figure 4 is an elevation of the said joint, but drawn upon an enlarged scale.
Figure 5 is a section of the said joint, similar to that shown in Figure 3, but
on the same scale as Figure 4.
Figure 6 represents an elevation of the joint pin and a section, edge view and
elevation of the locking nut, separately.
The same letters of reference indicate corresponding parts in the several figures
of the drawing.
The said adjustable joint consists of the bifurcated end a¹, of one leg a, of the
compass fitting upon a tongue or plate end 61, of the other leg b with a screw
pin c, passing through plain coincident holes a, b, in the joint ends of both legs,
one end of the said pin preferably having a large nicked head c', with the plain
face abutting against the cheek of one of the branches of the bifurcated end, whilst
the other end ², is wormed and takes a preferably hardened steel nut d, whose
inner side comes co-adjacent to or bears against the outer face or branch of the
bifurcated joint end. The head of the pin is notched, in which the blade of a knife
or the like is inserted to hold the same and prevent it from twisting on the screwing
of the nut.
By simply screwing up the nut on the end of the pin by a spanner, key or pair
of pliers the necessary stiffness is given to the joint and any wear is compensated
for.
The edges of the nut are preferably facetted or made square, hexagonal or of
other figure to facilitate the holding of the same whilst being rotated for tightening
up, and instead of having a head at one end of the cross pin, both ends of the same
may be screwed and be fitted with steel nuts.
As a modification the nut may be made in a convenient form for rotation by
the fingers alone, without the aid of tools, whilst in order to prevent the pin from
turning or twisting during the screwing up of the nut, the shank of the same may
be made square or facetted and take into a corresponding hole in the joint end of
one of the compass legs.
To prevent the nut from being unscrewed by the continuous opening and closing
of the legs of the instrument, the screwed end of the pin may have a flat upon it
and receive a washer pierced with a D-shaped hole, which is threaded upon the
pin and comes between the face of the joint end of one of the legs and the inner
side of the adjusting nut.
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:-
-
Providing the joint pin of the legs of compasses with an adjusting screw nut or
nuts, substantially as and for the purpose herein described and set forth.
D
£ 1000
FRANK HENRY SHAW.
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.