Improvements in Ball Castors for Furniture and the like.
Year: 1896

page_text: Date of Application, 5th May, 1896-Accepted, 8th Aug., 1896
COMPLETE SPECIFICATION.
Improvements in Ball Castors for Furniture and the like.
I, GEORGE JAMES SCHILLING COLLINS, of No. 195 La Salle Street, Chicago,
County of Cook, State of Illinois, United States of America, Mechanical Engineer,
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 improvements in castors for furniture and refers more
specifically to improvements in that class of castors in which the main supporting
roller is spherical and the bearings therefor are anti-friction ball bearings.
The object of the invention is to provide a simple and improved device of the
character referred to, especially designed with reference to the formation of
the parts therefor, exclusive of the roller balls, from sheet metal, by means
of stamping or drawing dies, whereby the castor may not only be more cheaply
produced, but is at once stronger, neater in appearance and more perfect than
those heretofore made, as is common, by casting. At the same time the device
embodies features of construction which render it more perfect in its operation,
less liable to become clogged or inoperative, and which facilitates the assemblage
and application of the castor.
The invention consists in the matters hereinafter described and more particularly
pointed out in the appended claims, and will be readily understood, reference being
had to the accompanying drawings, in which :-
Figure 1 is an axial section of the castor, showing the supporting roller and the
roller ball bearings in full lines.
Figure 2 is a horizontal section taken on line 2-2 of Figure 1, and looking
upward, the supporting roller being removed.
Figure 3 is a view similar to Figure 1, showing a modification.
Figure 4 is a side elevation of the castor shown in Figure 3, and
Figs. 5 and 6 show modifications.
As shown in said drawings, A designates the spherical supporting roller of the
castor, which is loosely seated within a casing, designated as a whole by B,
the lower end b, of which is open so as to allow the lower side of the ball A to
protrude therefrom to rest directly upon the floor. The casing B is composed of
two main parts B1 B2, which are of generally tubular form and arranged to
telescope one upon the other; the general form of the interior of the casing being
cylindric, with a closed upper end 6' and an internal or contracted lower end 6.
The upper closing end wall b¹ is shown in the present instance as being made flat
and arranged horizontally, or at right angles to the vertical axis of the castor, and
as forming the case or bearing part of the casing, through which the weight of the
piece of furniture to which the castor is applied is transmitted to the supporting
roller. The interior diameter of said casing B is slightly greater than the diameter
of the ball A, and its depth is such as to provide a suitable space or roller race
within the angle between the upper end wall 6' and the cylindric side wall within
which race are arranged a plurality of anti-friction roller balls CC which rest in
contact at their lower sides with the upper surface of the supporting roller A
and thus serve to transmit the weight from the base b' to said supporting roller.
Obviously, when thus constructed, weight brought upon the castor will hold the
anti-friction balls outward against the circular inner side wall 68 of the casing, and
will also serve to hold the supporting roller A centered within the casing and free.

page_text: from contact with any part thereof. It may also be noted that each of the roller
bearing balls C will have bearing contact at three-points only,-against the lower
surface of the base b', against the inner surface of the cylindric wall 63 and against
the upper surface of the ball A, as indicated at c, cl, c³, respectively. It may be
further noted in this connection that the arrangement is such that it is impossible
for said roller bearing balls to become wedged within the casing or to bind under
any circumstances.
As an improved construction, the number of balls arranged within the roller
race will be less than sufficient to completely fill said race circumferentially, four
being shown in the present instance, and in order to keep said roller balls spaced
apart so as to prevent their accumulation all at one side, a separating device D,
having the form of a spider provided with a plurality of radially extending arms dd
equal in number to the number of balls within the race, is arranged within the
upper end of said casing. Preferably and as herein shown, said spider is formed
of sheet metal stamped out in proper shape, the arms thereof being bent upwardly
from the central body portion d', so as to give the spider the form as a whole of a
truncated cone, the height of which is substantially equal to the distance between
the inner surface of the upper end wall 6' and the top of the main supporting
roller. Usually, in practice, the said spider will be arranged loosely within the
upper end of the casing, it being obvious that when the parts are assembled it will be
impossible for the separating device to become displaced or the roller balls
disarranged, while at the same time it is free to rotate with the balls around the
interior of the casing, thereby avoiding the friction which would result were said
spider secured rigidly within the casing and the run of the balls thus positively
limited.
As a preferred construction, the inner member B2 has the form of a plain
cylindric cap closed at one end and is conveniently formed by means of suitable
drawing dies in a well understood manner, while the outer member B¹ is constructed
to telescope upon the lower end of said inner member, the inturned lower end
portion of the outer member serving to limit the extent to which the inner
member extends within said outer member, as indicated clearly in Figure 1.
At its upper end the outer member B₁ is provided with a radial flange b
provided with screw apertures 6 spaced at intervals apart, by means of which
the castor may be secured to the leg of the article of furniture. Said outer
member B is also conveniently formed of sheet metal struck into proper form
by means of dies, the flange 64 thereof being either formed integral or made
separate and brazed thereto, as found convenient or desirable.
In applying the device to an article of furniture, the bottom surface of the leg
will be provided with a cylindrical recess of proper size and open to receive that
part of the inner member of the casing which protrudes above the annular flange b*,
thus allowing the latter to rest in contact with the end surface of the leg, after
which the screws will be inserted in an obvious manner. It may be noted in this
connection that the inner member B2 will ordinarily not be positively secured
within the outer member of the casing, this being unnecessary, inasmuch as it will
be held properly in place without additional securing means when the castor is
attached to the article of furniture.
In Figures 3 and 4 I have shown a modification more particularly designed for
application to chair legs, or the like. In this case, the outer member B³ of the
casing is unprovided with the radial flange 4, but is extended upward beyond the
upper end of the inner member to form a socket 6 adapted to receive the entire
end of the leg. In other respects, the construction of the castor is the same as
that previously described.
In Figures 5 and 6 I have shown modifications comprising a cylindric casing B
which is of uniform diameter throughout the principal part of its length, and
desirably of a length or depth, measured axially, about equal to its diameter. 5
Around the upper end of the cylinder is formed a bead, by bending the wall
thereof outward at right angles, as at 6 and. thence the remaining portion 67

page_text: upwardly at right angles to said first bend and parallel with the main wall of the
cylinder. The lower end of the cylinder is crimped or turned inwardly as at 68 so
that the distance between the lower edges thereof is slightly less than the greatest
diameter of the main supporting ball A which is to be placed therein. After the
said supporting ball has been placed within the cylindric casing described, and the
bearing rollers and separator therefor placed thereon, a flat circular disc E is
inserted within the upper end of said casing and allowed to rest at its edges upon
the shoulder formed by bending the walls of the casing outwardly, as described,
said disc being of such diameter as to completely fill the annular recess formed
thereby. The diameter of the supporting ball A and the small bearing rollers C
are such that when the parts have been assembled as described, the disc will rest
lightly upon the bearing rollers, and transmit the weight of the article of furniture
to which it is attached thereby to the main supporting roller. To retain said disc
rigidly in place and the parts in proper relation, the upper end of the casing is
crimped over the disc, as shown at 6°. Thus completed, the upper part of the
casing presents the appearance of a bead extending around its periphery, which
bead is rectangular in cross-section. Projecting upwardly from the centre of said
disc is a shank 610 adapted to enter an aperture in the end of the leg of furniture,
to be attached thereto. As will be apparent from the above description, the main
supporting roller will project below the lower end of the casing in such manner as
to expose about one-third of its area,-sufficiently to allow it to rest in contact
with the floor and give the outer casing sufficient clearance as to insure, that it will
in no case touch the floor.
From the foregoing description it will be seen that I have provided an
exceedingly simple, practical and economical construction and one possessing
important advantages. The arrangement of the roller balls whereby each ball is
permitted to roll back and forth freely within a limited space is important,
inasmuch as this action tends to keep the balls free from becoming clogged with
anything which the large supporting roller might pick up, such, for instance as
ravelings, pieces of gum or the like, while at the same time the construction is such
as to reduce the friction to a minimum. The assemblage of the several parts of
the castor is accomplished with the greatest facility, inasmuch as the inner member
forms a cup within which the several parts may be simply dropped into position one
after the other and the outer member thereafter telescoped upon the inner member,
thus completing the operation. By reason of the fact that the several parts are
made by means of dies, perfect uniformity is insured, while the finish of the article
is very much superior to that of a cast article, and it may be nickelled, lacquered, or
otherwise provided with an embellishing finish without preparatory dressing
or polishing.
While I have herein shown what I deem to be preferred embodiments of the
invention, yet it will be obvious that the details of construction may be varied
somewhat without departing from the spirit of the invention and without involving
more than ordinary mechanical skill. I do not therefore wish to be limited to the
precise details of construction shown, except as specifically claimed herein..
Having now particularly described and ascertained the nature of my said
invertion, and in what manner the same is to be performed, I declare that what
I claim is :-
1. A furniture castor comprising a spherical supporting roller, a casing within
which said roller is arranged, an annular anti-friction roller ball race in the upper
part of said casing arranged concentric with the vertical axis of the latter having
a cylindric wall at its outer side which confines the balls against radial outward
movement, a plurality of roller balls arranged in said race, serving to transmit the
weight brought upon the casing to said supporting roller and a movable ball
separating device provided with parts arranged to project within said race, between
each pair of balls therein so as to retain said balls at intervals apart, substantially
as described.

page_text: 2. A furniture castor comprising a spherical supporting roller, a casing within
which said roller is arranged, an annular anti-friction roller ball race in the upper
parts of said casing arranged concentric with the vertical axis of the latter, a plurality
of roller balls arranged in said race, serving to transmit the weight brought upon
the casing to said supporting roller, and a ball separating device provided with
parts arranged to project between each pair of balls within the race arranged
loosely within said casing, said ball separating device being free to rotate with
the balls and unaffected by weight brought upon the castor, substantially as
described.
3. A furniture castor comprising a spherical supporting roller, a casing within
which said roller is arranged, an annular anti-friction roller ball race in the upper
part of said casing arranged concentric with the vertical axis of the latter, a
plurality of roller balls arranged in said race serving to transmit the weight brought
upon the casing to said supporting roller and a ball separating device having the
form of a spider provided with a number of radial arms equal to the number of
balls within the race, and arranged to project between each pair thereof, said ball
separating device being free to rotate with the balls and unaffected by weight
brought upon the castor, substantially as described.
4. In a furniture castor, the combination of a main spherical supporting roller
a casing within which said supporting roller is confined, said casing comprising two
cylindric drawn sheet metal tubular members adapted to telescope one within the
other, the outer one of said members being made open at both ends but contracted
at its lower end to retain the supporting roller therein, and the inner member being
made of cap form or closed at its upper end, a plurality of roller balls arranged
within the upper end of the inner member, a ball separating device arranged loosely
within said casing and means for securing the castor to an article of furniture,
substantially as set forth..
5. In a furniture castor, the combination of a main spherical supporting roller,
a casing within which said supporting roller is confined, comprising two drawn
metal tubular members adapted to telescope one within the other, the outer member
being made open at both ends but contracted at its lower end to retain the
supporting roller therein, and provided at its upper part with an exterior radially
projecting flange, and the inner member having a closed upper end, a plurality of
roller balls arranged within the upper end of said inner member, and a ball
separating device having the form of a spider provided with radially extending
arms arranged to extend between each pair of roller balls, substantially as set
forth.
6. In a castor, the outer cylindric sheet metal casing B', provided with the
radially out-turned flange at its upper end, and the inturned lower end 6,
substantially as described.
7. In a castor, the inner cylindric sheet metal member B³ provided with the
closed upper end and open lower end, and arranged within the outer casing so as to
project above the latter throughout a portion of its length, substantially as
described.
8. In a castor, the outer cylindric sheet metal casing B³ of uniform diameter
throughout its length, and having the inturned or crimped lower end substantially
as described.
Dated this 5th dow of Mar 1906
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.