Year: 1899

page_text: Date of Application (in United Kingdom), 30th. Dec., 1899
Complete Specification Left, 1st Oct., 1900-Accepted, 15th Dec., 1900
I, ESTHER PRINCETTA HUDSON CARRAWAY, of 423, Effingham Street, Ports-
mouth, in the State of Virginia, United States of America, Inventor, do hereby
declare the nature of this invention to be as follows:-
This invention consists of a castor, comprising a body portion having a secur-
ing stem integral therewith and having a substantially hemispherical recess in
its under side, a groove in the wall of the lower portion of the recess resulting
in the formation of a lower increased cylindrical bore, and a race element
between the wall of the cylindrical bore and the wall of the hemispherical
recess, threads at the lower end of the body portion, a retaining ring engaging
the threads of the body portion and having a groove in the upper portion of
its inner surface resulting in the formation of an increased cylindrical bore
adapted to align with the similar portion of the body, and a race element
adapted to lie parallel with the race element of the body to form a race, rollers
mounted to travel in the race, a shaft journaled loosely in the rollers and
movable therewith, and a ball having a central passage, the ends of which are
flared outwardly and through which the shaft is passed, the surface of the ball
surrounding the ends of the passage being adapted to contact with the rollers
to hold the ball from engagement with the body and the ring.

page_text: This invention relates to ball-casters, and has for its object to provide certain
new and useful improvements in the structure of the mounting of the ball
which permit the ready assembling of the parts.
To this end the present invention consists in the combination and arrange-
ment of parts as will be hereinafter more fully described; shown in the accom-
panying drawings, and particularly pointed out in the appended claim, it being
understood that changes in the form, proportion, size, and the minor details of
construction may be made within the scope of the appended claim without
departing from the spirit or sacrificing any of the advantages of the present
invention.
In the drawings,
Figure 1 is an elevation of a caster, showing the same fitted to the leg of
a piece of furniture.
Figure 2 is a longitudinal sectional view thereof.
Figure 3 is a bottom plan view having the ball-retaining cap or ring removed.
Corresponding parts in the several figures of the drawings are designated by
like characters of reference.
Referring to the accompanying drawings, 1 designates the body of the caster,
which is substantially hemispherical and is provided with a socket or recess 2,
opening outward through the flattened side of the caster-body. Located at the
opposite side of the body and projecting exteriorly therefrom is the usual
attaching-shank 3, which is adapted to be fitted to the leg 4 of a piece of furni-
ture in the common or ordinary manner.
As best shown in Figure 2 of the drawings, it will be seen that the socket 2
is widened near the mouth thereof, whereby an inner annular shoulder 5 is
provided and also a pendent peripheral flange 6. Located within the socket 2
is the ball 7, which is provided with a horizontal axial bore 8, the diameter
of which is smallest at a point midway between the opposite ends of the bore,
and the latter uniformly increases in size from the center outwardly and in
opposite directions therefrom. Mounted loosely within the bore of the ball is
a shaft 9, which projects equally beyond the opposite ends of said bore and
has a bearing upon the ball only at the intermediate point 10, where the
diameter of the bore is smallest. The opposite projecting ends 11 of the
shaft 9 provide journals upon which are loosely mounted the disk rollers or
wheels 12, which are received in the groove formed between the annular
shoulder 5 and the peripheral flange 6, so that said rollers are adapted to engage
with and travel upon the annular shoulder 5. In order that these movable
parts of the caster may be held in position, there is provided a retaining-
ring 13, which has an upstanding peripheral flange 14, threaded exteriorly and
adapted to be fitted to the interiorly-threaded portion of the peripheral flange G.
This retaining ring or cap has an opening 15, through which the lower side of
the ball is adapted to project and rest upon the floor, and the upper side of the
ring is also provided with an inner annular groove 16, adapted to receive the
lower side of the rollers 12. It will be noted that the groove 17 in the body
of the caster and also the groove 16 in the retaining-ring are adapted to
register, so as to form a large annular groove receiving and confining the
rollers 12, and also the sides of the ball, at the opposite ends of the bore
therein, are flattened as at 18, so as to accomodate the adjacent flat sides of
the disk rollers, and thereby prevent the latter from having a wabbling or
lateral movement upon the journals 11 or ends of the shaft 9.
By reason of the oppositely-tapered shape of the bore of the ball the latter
has a bearing at a single point only intermediate of the ends of the shaft,
whereby friction is reduced to a minimum, and should the ball be canted or

page_text: tilted the gradually-increasing size of the bore will prevent the same from
binding upon the shaft, thereby insuring a positive and easy turning of the
ball. The annular shoulder 5 of the body of the caster rests upon the periphery
of the rollers 12 at the upper sides thereof, and the shaft 9 is supported
intermediate of its ends upon the lower wall and at the narrowest portion of
the bore 8, whereby the ball is capable of turning upon its vertical axis, and
the rollers 12 turning loosely upon the ends of the shaft and traveling against
the comparatively small surface presented by the annular shoulder 5, the fric-
tion caused by such movement is also reduced to a minimum.
It will be noted that the ball 7 does not engage the walls of the socket 2;
but the body of the caster is supported at opposite points upon the rollers 12
and the shaft 9 engages the ball at only one point, whereby the frictional
surfaces are greatly reduced and a substantially three-point bearing is provided.
To facilitate the positioning and removal of the retaining cap or ring 13,
the latter is roughened or serrated exteriorly, as indicated in Figure 1 so that
the same may be firmly grasped by the hand.
The present invention provides an exceedingly simple and useful caster, in
which the parts are few in number and are assembled together in a manner
to prevent accidental displacement thereof, and, furthermore, the points of
frictional contact are reduced to a minimum, so that the caster is adapted to
work quickly and easily.
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:
A caster comprising a body portion having a securing stem integral there-
with and having a substantially hemispherical recess in its under side, a groove
in the wall of the lower portion of the recess resulting in the formation of a
lower increased cylindrical bore, and a race element between the wall of the
cylindrical bore and the wall of the hemispherical recess, threads at the lower
end of the body portion, a retaining-ring engaging the threads of the body
portion and having a groove in the upper portion of its inner surface result-
ing in the formation of an increased cylindrical bore adapted to aline with the
similar portion of the body, and a race element adapted to lie parallel with the
race element of the body to form a race, rollers mounted to travel in the race,
a shaft journaled loosely in the rollers and movable therewith, and a ball
having a central passage, the ends of which are flared outwardly and through
which the shaft is passed, the surface of the ball surrounding the ends of the
passage being adapted to contact with the rollers to hold the ball from engage-
ment with the body and the ring.
Dated this 29th day of September 1900.
For the Applicant,
J. G. LORRAIN,
Norfolk House, Victoria Embankment, London, W.C.,
Chartered Patent Agent.