Year: 1887

page_text: Date of Application, 22nd Dec., 1887
Complete Specification Left, 22nd Sept., 1888
Complete Specification Accepted, 26th Oct., 1888
I, HENRY REGINALD ARNOLD MALLOCK, of Bornhill House, near Exeter, in the
County of Devon, Gentleman, do hereby declare the nature of this invention to he as
follows:-
:-
In ball castors, as they are frequently made, a main ball intended to roll along the
floor is retained within a socket which is a segment of a hollow sphere of larger radius
than the ball, and small balls are placed in the socket between the two spherical
surfaces so as to form rollers to facilitate the revolution of the main ball. When the
castor is moved, these small balls are caused to roll towards the front part of the lower
zone of the socket, where they become crowded together impeding their own revolution
and that of the main ball.
My invention relates to a modification of the form of the socket whereby I over-
come this difficulty. The socket being made as a spherical segment extending down
some distance below what may be termed the equatorial plane, or the horizontal plane
passing through the centre of the main ball, I make the zone of the socket which
lies about this plane of a somewhat larger radius than the upper part, easing off with
a gentle slope the shoulder which would otherwise present itself where the increase of
radius takes place. The balls, on successively reaching this enlarged zone, have
freedom to travel along it backwards until they reach its hinder part, whence they
are caused to roll upwards, so that they can again roll forwards along the upper part
of the socket. Thus the crowding of the balls in front is avoided and a continuous
succession of balls, forming rollers for the main ball, is ensured throughout the space
between it and the socket.
Datad this 2nd day of December 1887
ABEL & IMRAY,
Agents for the Applicant.

page_text: I, HENRY REGINALD ARNOLD MALLOCK, of Bornhill House, near Exeter, in the
County of Devon Gentleman 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 :-
In ball castors, as they are frequently made, a main ball intended to roll along the
floor is retained within a socket which is a segment of a hollow sphere of larger radius
than the ball, and small balls are placed in the socket between the two spherical
surfaces so as to form rollers to facilitate the revolution of the main ball. When the
castor is moved, these small balls are caused to roll towards the front part of the
lower zone of the socket, where they become crowded together impeding their own
revolution and that of the main ball.
My invention relates to a modification of the form of the socket whereby I over-
come this difficulty. The socket being made as a spherical segment extending down
some distance below what may be termed the equatorial plane, or the horizontal plane
passing through the centre of the main ball, I make the zone of the socket which lies
about this plane of a somewhat larger radius than the upper part, easing off with a
gentle slope, the shoulder which would otherwise present itself where the increase of
radius takes place. The balls, on successively reaching this enlarged zone, have
freedom to travel along it backwards until they reach its hinder part, whence they
are caused to roll upwards, so that they can again roll forwards along the upper part
of the socket. Thus the crowding of the balls in front is avoided and a continuous
succession of balls, forming rollers for the main ball, is ensured throughout the space
between it and the socket.
The accompanying drawing is a vertical section of a ball castor according to my
invention. The main ball A is placed in a spherical socket C of larger diameter with
a number of small balls B interposed between the ball and the interior of the socket.
A zone DE of the socket extending a little above and below the equatorial plane of
the ball A is made with radius a little larger than that of the rest of the socket, so
that the small balls B, when they reach that zone, are quite free to move along it
from the front, to which they are brought by the rolling action, to the back where
they are again ready to be rolled forwards.
The change of radius at D is not abrupt but the one surface is made to slope
gently into the other. The balls are held in the socket by a cover ring F screwed
into the mouth of the socket or otherwise fixed therein. The castor has a stem G by
which it can be screwed to the leg of a table, chair or other article of furniture, or,
instead of a screwed stem G it might have a socket to embrace the leg, or it might
terminate in a plate fixed by several screws.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
The construction and use of a castor, wherein a main ball rolls on numerous small
balls contained in a socket which is a segment of a hollow sphere having at its lower
part a zone of greater radius than that of the upper part, substantially as and for the
purpose herein set forth.