IMPROVE- MENTS IN FURNITURE CASTORS
Year: 1884

page_text: I, EDMUND WRIGHT of 54, Hamstead Road Handsworth in the County of
Stafford, Engineer do hereby declare the nature of my Invention for "IMPROVE-
MENTS IN FURNITURE CASTORS" to be as follows:-
My Invention has reference to ball castors for furniture or other moveable
articles and comprises improvements in the construction of the upper or bearing
part of the castor whereby the friction on the ball is reduced allowing it revolve
freely in any direction. For this purpose I employ a number of rollers set in a
circular frame which may be made in the upper part of the castor itself or inserted
seperately the rollers being placed at angles of equal degrees radiating from the
centre of the said frame. In the construction of the roller frame the ring of metal
is slotted or cast with small openings at its edges for the purpose of receiving the
rollers, while the inner part is recessed for a sufficient distance to hold a ring of .
wire which forms a common axle on which the whole of the rollers may freely.
revolve. While the article of furniture to which the castor is attached remains
stationery, the rollers rest with equal pressure on the central ball, but on its being
moved the friction of the floor or carpet causes the ball to press.most heavily
against those rollers which are immediately behind the line of resistance, which by
their tendency to run-up the inclined surface of the ball partially release the
pressure of the rollers on its sides and front and thus allow it to revolve freely in
the desired direction-It is necessary to employ a sufficient number of rollers for
this purpose as the more accute their radiating angle from the centre of the frame
the greater the probability of the propelling roller or rollers which actuate the ball
being brought directly behind the line of resistance-I am aware that three
equi-distant rollers have been used for this purpose, in which case, where there is
an equal pressure of two behind the ball, the incline of the balls surface at their
point of contact is so slight as to cause them to override it thus forcing the ball
against the bottom of the cup which holds it in position and preventing it rolling.
I prefer to use at least eight rollers, although more may be used with advantage.
In the construction of the castor to retain the ball in position, it is enclosed by an
open-ended cup which may also be made to cover the roller frame-The roller.
frame or the entire castor may also be made with a central bearing pin and left to.
revolve by its own vibration, which obviates any unequal wear on the rollers
where the articles of furniture are frequently being moved backwards and forwards
in one direction.
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500 1
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page_text: .
2
I, EDMUND WRIGHT of 54, Hamstead Road, Handsworth in the County of
Stafford, Engineer do hereby declare the nature of my Invention for
IMPROVEMENTS IN FURNITURE CASTORS' " and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement
-
My Invention has reference to ball castors for furniture or other moveable
articles and comprises improvements in the construction of the upper or bearing
part of the castor whereby the friction on the ball is reduced allowing it to revolve
freely in any direction.
1
This Invention will be more readily understood by reference to the accompanying
Drawings in which similar letters of reference indicate corresponding parts in the
several Figures.
Fig. 1. is an elevation and Fig. 2, a semi-sectional view of the improved castor,
specially adapted for tables, chairs and wooden furniture-In this illustration the
castor is made with the socket a. and a sufficient quantity of metal is allowed on
its under side to construct the roller frame b. The construction of the latter will
be best seen by reference to Figs. 3. & 6. in which c. is an annular ledge (which
may be slightly undercut or square in the corner) for receiving the spring axle e.
Fig. 5. and d. are slots cut or cast in the solid metal for receiving the friction
rollers. The spring axle e, is first placed through the rollers . and is then
compressed as shewn by the dotted lines Fig. 5. Both axle and rollers are then
placed in position and are firmly retained therein by the outward pressure of the
axle e. as shewn in Fig. 6. which is a view of the underside of the roller frame
with the central ball f. Fig. 2. removed.
Fig. 3 illustrates a method of attaching the castor to a central pin or bearing
which allows it to revolve, thus obviating any unequal wear on the friction rollers
where the article of furniture is continually being moved in one direction-m. is a
central bearing pin flanged at n. which may be attached to any article of furniture
by the screws p. p. The pin m. fits easily in the socket or recess r. and is held
from withdrawal by means of the screw or pin o. and the groove s. Fig. 7, is a
sectional view of the open-ended cup l, which retains the central ball f, Fig. 2. in
position, when it is requisite to lift the article of furniture from the ground. In
attaching this cup I first tin the inner edges for a sufficient distance at t. t. and the
outer edges of the roller frame at u. u. Fig. 3. and after placing the rollers, axle
and central ball in position, I enclose them with the cup l. first applying a sufficient
amount of heat to the latter to melt the tin or solder, and on cooling, the parts
t, t, & u. u, firmly adhere to each other, the castor assuming the shape shewn
in Fig. 1.
•
In addition to the above method of securing the cup it may also be screwed or
pinned on the roller frame.
Fig. 4, illustrates a method of attaching the castor to a metallic bedstead-The
upper part of the castór b, b, instead of being made with a socket has a projection
at z. which may be cast plain or grooved. The finished castor is then placed on
one side a sand mould of any desired shape the leg of the bedstead yy, being
placed opposite-molten' metal as shewn,at x, is then poured into the mould by
which on its cooling the castor and leg are firnily held together. The operation. of
this castor is as follows-On pressure being applied in any desired direction-
say in the direction of the arrow at g. Fig. 2, the resistance of the carpet or floor
on the base of the central ball at h, causes it to press most heavily on the roller or

page_text: rollers opposite or near g. which by their tendency to rise to the apex of the ball
at k. diminish the friction on those rollers which are at the sides and in front of
the line of resistance at h, thus allowing the ball to revolve freely in the desired
direction. It will be obvious that as in general use the movement of any article
of furniture is multifarious, the greater number of rollers there are used, the
greater is the probability of there being one directly opposite the line of resistance
which position at all times. allows the freest movement to the central ball. These
latter are found to roll freely even if somewhat irregular in shape, and may be
made of metal, wood, glass, pottery-ware or any suitable material. As in general use
ball castors are liable to gather lint and dust I make a small aperture in any
convenient place for its removal, and I would have it understood that in the
construction of this castor and the various methods of attaching it, I do not
confine myself to any precise details of size, shape, or material.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is-
1. The construction of a ball castor containing friction rollers i. with the self
contained slots or grooves d. for receiving the said rollers without the intervention
of a seperate plate or frame and brackets and having an annular ledge c, undercut
or otherwise on which is held the spring axle e, substantially as described.
2. In combination with any number of rollers, the circular axle e. made as a
spring and retained in position by its own elasticity, substantially for the purposes.
herein specified.
3. In a ball castor containing friction rollers the method of attaching the lower
part or cup . to the upper part by means of soldering or "sweating" substantially
as herein set forth.
4. A ball castor having a central bearing which allows it to revolve freely and
independently of the article to which it is attached substantially as shewn and
described.
'
5. The attachment of ball castors to the legs of metallic bedsteads by means of
molten metal which on cooling unites both together substantially as herein shewn
and described.