Improvements in Furniture Castors.
Year: 1891

page_text: Date of Application, 13th Oct., 1891-Accepted, 6th Feb., 1892
COMPLETE SPECIFICATION.
Improvements in Furniture Castors.
I WILLIAM JAMES HARPER of Sandbach in the County of Chester, Stationer,
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 :-
This invention relates to the construction of that class of furniture casters known
as wheel or roller casters and the objects of the invention are to reduce friction and
to enable the furniture to be moved from place to place more easily and noiselessly
than heretofore.
The nature of my said invention and the manner in which the same is to be
performed will be readily understood on reference to the sheet of drawings and the
following explanation thereof.
The invention consists principally in the combination with a roller caster fitted
with ball bearings, of a wheel or roller fitted with an india rubber tyre, by which
combination I obtain a perfectly free trailing action in all directions coupled with
absolute noiselessness and absence of vibration.
Fig. 1 on the annexed drawing represents a side elevation of a caster made
according to my invention and
Fig. 2 is a partial section thereof,
Fig. 3 is a section of the wheel or roller showing the application of the india
rubber tyre thereto.
The class of caster illustrated is that which is provided with a peg and is secured
to the leg or other part of the furniture by means of a screw plate and screws, but
it will be evident that my invention is equally applicable to those casters which are
attached by means of a socket as shown by dotted lines at Fig. 1.
b
a is the peg, 6 the screw plate into the centre of which the peg is driven tightly,
and c is the "horn" which is made with a central boss c¹ in which is cast or formed
a hole of such a diameter as will turn loosely upon the lower part of the peg a the
bottom end a' of which is passed through a washer d and rivetted, or otherwise
secured.
I make the ball-bearing in the following manner. I cup out the upper end of the
hole in the boss c' so as to form a channel round the peg in which I insert a
convenient number of balls e (preferably of hardened steel) the channel being of
such a depth and the balls e of such a diameter that the latter project above the
upper surface of the "horn c and the lower surface of the screw plate 6 (or of the
socket if employed) rests upon and is supported by the balls e and the friction is
thus reduced to a minimum.
"
The balls e are of course placed in position when the caster is being put together
and before the lower end a¹ of the peg is rivetted.
I may here observe that the ball bearing may be made in other forms but the
above described is the form which I consider best adapted for the purpose being
perfectly efficient in action and economical in manufacture.
To further improve the running of the caster and to make the same noiseless in
its action I turn or form a groove round the periphery of the wheel or roller fas
shown at Fig. 3 and insert therein a ring or band 9 of india rubber or other
suitable elastic and compressible material which may be of round, oval, or other
suitable section, and may either be kept in its place by its own contraction, or if
preferred it may be cemented or otherwise fastened therein. But I find cementing
is in most cases not required because the combination of the ball bearing gives such
absolute freedom of motion in any direction that there is no tendency to pull the
tyre out of the groove in the wheel or roller.

page_text: In some cases (especially for the more expensive kinds of casters) I propose to
make the axle of the wheel or roller fin the form of a screw as shown (or other-
wise removable) so that at any time, if required, the said wheel or roller may be
taken out and supplied with a fresh band or tyre g.
Furniture casters made according to this invention will be found to have a more
easy and continuous motion than any at present in use, and at the same time to be
perfectly silent and free from vibration and not liable in any way to injure either
a carpet or other floor covering or a polished floor.
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 :-
First. In furniture casters the combination of a ball bearing between the
"horn" and "peg" with a grooved wheel or roller fitted with an india rubber or
other suitable tyre.
Secondly. I claim the particular construction of ball bearing for furniture
casters substantially as hereinbefore described and illustrated by the drawings
annexed.
Dated this 12th day of October 1891.
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicant.