Improvements in Castors for Pianos, Sofas, Chairs, Tables, Bedsteads, and other Articles of Furniture.
Year: 1886

page_text: Date of Application, 22nd Apr., 1886.
Complete Left, 21st Dec., 1886.
Complete Accepted, 8th Feb., 1887.
Improvements in Castors for Pianos, Sofas, Chairs, Tables,
Bedsteads, and other Articles of Furniture.
WILLIAM RANKIN 146 Renfield Street, Glasgow, Letterpress Printer, do hereby
declare the nature of this invention to be as follows:-
A ball revolving in a cup or socket, thereby sustaining in a straight or vertical
line, the weight of the article to which it is affixed.
This cup or socket is attached to any desired part of the furniture, and forms a
bearing and guide for the ball, thus allowing it to rotate in any direction.
.
By this invention the socket and revolving ball, and the part of the article to which
it is attached are always practically in the same vertical centre line. It thus possesses>
the great advantage of not straining the furniture, as is done with the ordinary
overhung wheel of the common castor.
WILLIAM RANKIN.
Improvements in Castors for Pianos, Sofas, Chairs, Tables,
Bedsteads, and other Articles of Furniture.
1, WILLIAM RANKIN, Letterpress Printer, 146 Renfield Street, Glasgow, do hereby
declare the nature of my Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement,
reference being made to the accompanying Drawing and to the letters and figures
marked thereon :-
My Invention relates to Ball Castors, and consists of only two parts-the cup or
receptacle, and the ball-all small rollers or balls for the purpose of reducing friction
being dispensed with. By a particular arrangement of seating or bearing for the ball
in the cup or receptacle, the rotating of the ball is always assured..

page_text: In order that my said Invention may be fully understood, I proceed more
particularly to describe the same, and for that purpose I shall refer to the several
Figures on the Sheet of Drawings hereunto annexed-the same letters of reference
indicating corresponding parts throughout all the Figures.
Fig. 1 shews a side elevation of my improved Ball Castor, with screw at top for
attachment.
Fig. 2 shews a sectional elevation of Castor, with flange at top for.attachment.
Fig. 3 shews a sectional elevation of Castor, with socket at top for attachment.
Fig. 4 shews a sectional plan of same through line A A.
The Castor consists of only two parts-the cup or receptacle G, and the ball E.
The cup has neither rollers nor balls, nor any moving parts whatever, inside or
outside, to aid the rotation of the ball E, but it has a turned rest or seating or
bearing B for the ball-this bearing being placed in any desired position above the
horizontal centre line of the ball when it is in position and ready for operation. The
distance from bottom of ball to centre of bearing B, as shewn by arrow heads and
line C, is five times greater than is the distance from centre of bearing B to top of
ball, as shewn by arrow heads and line D, thus giving a leverage of five to one in
favour of the ball revolving rather than sliding. This leverage may be made as
desired.
may
I propose to make this rest or bearing either in a complete ring or
be cut
into sections, with spaces between, as shown in Fig. 4, through which wool, flock, or
thread may be carried into the space surrounding the top of the ball. The cup having
been cast and turned for the easy admission of the ball, has also two or more elongated
forks or projections F extending below the horizontal centre line of ball, which, having
been slightly compressed, prevent the ball from dropping out when the article is lifted
from wherever it may have been resting. The Castor may be made in various forms
for attaching to the varied articles of household furniture, or sewing machines or
musical instruments, for which it is adapted.
It may be made with a screw as shewn in Fig. 1, or with a flange as in Fig. 2, or
with a socket as in Fig. 3, or any other approved method of attachment. The cup G
may be made of brass or other metal; and the ball B should be a perfect sphere, or
as nearly so as practicable, and if made of brass or other metal, may either be cast
solid or hollow, or it may be made of earthenware, glass, or other substance.
Having now described, and particularly ascertained the nature of my said Invention,
and the manner in which the same is to be performed, I would observe, in conclusion,
that what I claim as novel and original is :-
First. The arrangement of the seating or bearing of the ball, as described, whereby
the certainty of the ball always revolving is assured. No matter what weight may be
placed on the article to which the Castor is attached, the leverage always remains the
same.
Second. The arrangement of forks or extensions as described, thus enabling the cup
to be made in one piece, and the ball taken out of or put into the cup or receptacle at
pleasure, by simply expanding or compressing the forks.
Third. The combination of the arrangenient of seating, and the arrangement of
forks or elastic extensions, either for Castors or for other mechanical purposes,
substantially as shewn and described.