IMPROVEMENTS IN BALL CASTORS
Year: 1878

page_text: LETTERS PATENT to Henry Beckett Harding, of No. 120, Caledonian Road,
Islington, in the County of Middlesex, for the Invention of "IMPROVEMENTS
IN BALL CASTORS."
Sealed the 6th May 1879, and dated the 20th November 1878.
PROVISIONAL SPECIFICATION left by the said Henry Beckett Harding at
the Office of the Commissioners of Patents on the 20th November 1878.
HENRY BECKETT HARDING, of No. 120, Caledonian Road, Islington, in the
County of Middlesex. "IMPROVEMENTS IN BALL CASTORS."
This Invention is intended to supply that great desideratum in household furniture,
a castor having vertical bearing and action and universal rotation; which also is not
liable to break down nor get out of order.
It consists of a circular metal case enclosing a ball which acts as the wheel of the
castor.
The ball is of metal, case-hardened and burnished, or of other very hard and
smooth material
The case is made in two portions which separate horizontally near the greatest
circumference of the ball. They are united by a screw joint.
The upper section of the ball chamber has two slightly projecting rings running
round its inner surface, one at the top, the other near the mouth.
A separate cup having these rings may be introduced into this part of the
chamber. This cup I cast in a hard antifrictional metal.
It is essential that the rings which form the bearing surfaces should be hard and
truly formed.
The lower portion of the case is a band which prevents the ball falling out of its
chamber; it has also a hard antifrictional ring around its inner surface so placed as
to prevent the ball in any of its movements coming into contact with this portion
of the case.

page_text: The top ring takes the whole of the vertical pressure of the ball, and the side
rings the whole of its lateral pressure; the rings are the only points at which the
ball has contact with the case. The rings and the ball present to each other very
small areas of contact, and the frictional surface in this castor so reduced that the
ball does not cease to revolve freely under very heavy pressure.
These castors fasten on from the inside of their case, and in a such manner as to
render their coming off or getting loose almost impossible, imparting also a neater
appearance to the furniture.
Some of them are made with a socket for the reception of the foot of the article
of furniture, and others are adapted for being partially sunk into the foot.
In each case screws are carried up through holes in the upper portion of the ball
chamber or cup into the leg.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Beckett Harding in the Great Seal Patent Office on the
20th May 1879.
HENRY BECKETT HARDING, of No. 120, Caledonian Road, Islington, in the
County of Middlesex. IMPROVEMENTS IN BALL CASTORS."
"
This Invention is intended to supply that great desideratum in household
furniture, a castor having vertical bearing and action and universal rotation, which
also is not liable to break down nor get out of order.
It consists of a circular metal case enclosing a ball which acts as the wheel of
the castor.
The ball is of metal, case hardened and polished, or of other very hard and
smooth material.
The case is made of hard antifrictional metal and in two portions which separate
horizontally near the greatest circumference of the ball. They are united by a
screw joint.
The upper section of the ball chamber has two slightly projecting rings running
round its inner surface, one at the top, the other near the mouth or screw joint.
It is essential that the rings which form the bearing surfaces should be hard and
truly formed.
The lower portion of the case is a band which prevents the ball falling out of its
chamber; it is also formed of hard antifrictional metal, and has also an antifrictional
ring around its inner surface so placed as to prevent the ball in any of its move-
ments coming into contact with this portion of the case otherwise than upon the
narrow surface of the truly formed ring.
The top ring takes the whole of the vertical pressure of the ball, and the side
rings the whole of its lateral pressure; the rings are the only points at which the
ball has contact with the case. The rings and the ball present to each other very
small area of contact, and the frictional surfaces in this castor are so reduced that
the ball does not cease to revolve freely under very heavy pressure.
These castors fasten on from the inside of their case, and in such a manner as to
render their coming off or getting loose almost impossible, imparting also a neater
appearance to the furniture.
Some of them are made with a socket for the reception of the foot of the article
of furniture, and others are adapted for being partially sunk into the foot.
In each case screws are carried up through holes in the upper portion of the ball
chamber or cup into the leg.
In order that my said Invention may be most fully understood and readily
carried into effect I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical section of a ball castor constructed according to my
Invention.
a is the ball, by preference of hard metal, truly formed and highly polished.
b is the upper cup or portion of the case; it is cast of the hard metallic mixture
known as phosphor bronze, and it is turned with two rings, one at the top, 61, which
supports the vertical load, and the other at 63 around the mouth or joint. It is
upon these rings alone that the upper part of the case can come into contact with
the ball.
c is the lower part of the case adapted to the upper part by a screw joint; it also
has a ring c¹ formed around its lip or lower edge. The ring c¹ is usually, and when
the castor is at rest, just out of contact with the ball; in travelling however the
edge of this ring occasionally touches the ball, but nowhere else can contact occur
between the lower part of the case and the ball.

page_text: The castor shown in Figure 1 is formed with a socket b³ forming part of the
upper cup or part of the case. The leg of the piéce of furniture is recessed to
receive this socket which it is made to fit to accurately both within and without.
The castor is also secured by a screw d inserted from the inside.
Figure 2 shows in elevation (partly in section) another form of castor; its upper
part is adapted to be let into the under side of a piece of furniture; a central
screw d serves to secure it.
Figure 3 is an elevation, partly in section, showing another arrangement of the
socket for attaching the castor, admitting of the use of screws at the sides as well
as the central screw d inserted from the inside.
Figure 4 shows a castor similar to Figure 2, but furnished with a double ring of
india rubber or other flexible material to exclude dust or other matter from the ball
chamber.
The upper portion of the double ring is retained by the edge of the lower cup c
which is rolled or turned over it in such manner as to prevent it escaping.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that I claim,—
First. The construction of ball castors with antifrictional supporting rings by
which the surface between the ball and the case is reduced in area, and the ball kept
from contact with other parts of the case.
Second. The means for securing the castor in its place by the socket let in or
inserted into the piece of furniture and made fast by a screw d introduced from the
interior of the case, as described in respect to Figure 1.
Third. The means for securing the castor in its place, as described in respect to
Figures 2, 3, and 4.
Fourth. The construction of ball castors, substantially as described, and represented
in the annexed Drawings.
In witness whereof, I, the said Henry Beckett Harding, have hereunto set
my hand and seal, this Twentieth day of May, in the year of our Lord
One thousand eight hundred and seventy nine.
TT TARTA