Improvements in Furniture Castors.
Year: 1896

page_text: Date of Application, 15th Feb., 1896-Accepted, 21st Mar., 1896
COMPLETE SPECIFICATION.
Improvements in Furniture Castors.
I, JAMES WILSON, of 4 Outram Street, Caledonian Road, in the County of
London, N., Metal Turner, 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:-
Furniture castors of the type known as ball castors are subject to the drawback
that they collect carpet fluff and soon get clogged.
The main object of my invention is to overcome this drawback but my invention
also embraces a new or improved arrangement and combination of parts constituting
a convenient type of ball castor.
In order that my invention may be more readily understood I shall proceed to
describe it with reference to a form thereof, the said form constituting a type or
illustration of my invention and giving good results in practice.
This form I have illustrated in the accompanying sheet of drawings in which
Figure 1 is a longitudinal section.
Figure 2 a plan view of the bearing balls and main ball seen without any support
and disconnected from the other parts.
Figure 3 an underneath plan view of the base of the socket showing the race for
the bearing balls.
Figure 4 is a modification of the form illustrated in Figures 1, 2 and 3.
In these figures 1 is the ball socket containing the main ball 2 which latter is free
to rotate on any of its geometric axes within the said ball socket and which when
in use presses upon the bearing balls 3 which latter are free to run in the annular
race 4 cut or otherwise formed in the base 5 of the socket. In the side walls of the
ball socket I form orifices 6 which I shall hereinafter term "fluff" orifices. The
fluff orifices may be of any convenient form and there may be any convenient
number of them, and arranged in any suitable manner.
In practice I find that the form of orifice shown in Figure 4 is very suitable and
that good results are obtained by placing the centre of the orifices at or about the
level of the contact points between the main ball and the bearing balls. I find it
convenient to employ a number of orifices slightly in excess of the number of
bearing balls but care must be taken not to employ so large a number of orifices
as to seriously weaken the walls of the ball socket.
It will be seen that by the provision of the fluff orifices it is impossible for the
castor to become clogged as any fluff collected within the ball socket is worked out
by the balls through the said fluff orifices.
I desire it to be understood that I do not limit myself to the precise structural
details hereinbefore set forth and illustrated, as, the principle of my invention
being understood, persons skilled in the art to which it appertains will be able to
modify the details to an indefinite extent without departing from its spirit.
For convenience of illustration I have omitted the shading from the main ball in
Figures 2 and 4.
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. In a ball castor the provision of fluff orifices substantially as and for the
purpose set forth.
2. In a ball castor the combination of a ball socket, fluff orifices in the walls of

page_text: the said socket and one or more balls within the said socket substantially as and for
the purpose set forth.
3. In a ball castor the combination of a ball socket having fluff orifices therein,
a main ball, bearing balls for the same and a race for the said bearing balls sub-
stantially as set forth.
For the Applicant,
J. G. LORRAIN, M.I.E.E., M.I. Mech. E.,
Norfolk House, Norfolk Street, Strand, London, W.C.,
Chartered Patent Agent.