IMPROVEMENTS IN CASTORS
Year: 1860

page_text: PROVISIONAL SPECIFICATION left by Richard Telford at the Office
of the Commissioners of Patents, with his Petition, on the 13th February
1860.
I, RICHARD TELFORD, of Birmingham, in the County of Warwick, Cabinet
Brassfounder, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN CASTORS," to be as follows:-
My Invention has for its object, in the first place, the construction of castors
in such a manner as to relieve the centre pin from the strain to which it is
ordinarily subjected, by transferring the same to the lower part of the socket
and to the upper part of the horn or carriage.
For this purpose the upper part of the horn or carriage is formed with a
hook at the back which embraces a projecting flango on the lower edge of the
socket, whilst the rest of the upper face of the horn or carriage is plain, and
merely presses against the lower face of the socket. By this means when the
weight is put on the castor the downward strain is sustained by the hook which
embraces a portion of the projecting flange of the socket, and the upward
strain is borne principally by the front portion of the horn or carriage bearing
up against the socket, thereby relieving the centre pin or stud from strain,
except such as is due to the keeping of the horn or carriage steady, so that it
may turn easily on the pin as a centre. The required connection between the
lower part of the socket and the upper part of the horn or carriage may be
formed by means of a groove instead of a flange or by other means, so long as

page_text: the forms and arrangements of these parts be adapted to sustain the upward
and downward strains in the manner above stated.
My Invention has for its object, in the second place, the application of springs
to castors in such a manner as to render them self-adjusting or capable of
accommodating themselves to uneven surfaces over which they may run. For
this purpose a spring or springs of the required strength is or are applied to
the centre pin so as to have a bearing against a collar or other fixed part
of the socket, by means of which the centre pin is immediately restored to its
vertical position when the uneven part of the surface is passed over. The
form of the spring and the material of which it is composed, and also the mode
of applying it may be varied.
My Invention consists, in the third place, in the manufacture of dumb
castors composed of glass or other material adapted for bearing weights and
sliding smoothly over carpets or such like surfaces, in the form of a solid half
ball with a stem having a screw thread on it by which it may be screwed into
furniture.
And my Invention consists, in the last place, in the application of vulcanite
of india-rubber or vulcanized india-rubber or gutta percha to rollers for castors.
For this purpose I take what is known in commerce as vulcanized india-
rubber which I roll either into lengths somewhat like paper rollers, or slabs of
any required thickness, and I cut the same into strips or round pieces by means
of a circular saw or a band saw, or I cut them out with a hollow punch, or a
bit and brace, such tools or mechanism being worked either by hand or by
mechanical power, or I press out the pieces by hydraulic or other power. I
then turn the pieces so cut in a lathe as in wood turning, and polish them
with rottenstone and water; or I polish them by turning them round rapidly
in a "tumbler" or hollow cylinder, similar to a barrel churn or coffee roaster.
But the mode of manufacturing the vulcanite of india-rubber or vulcanized
india-rubber or gutta percha may be varied.