IMPROVEMENTS IN CASTORS AND ANTI- FRICTION ROLLERS
Year: 1871

page_text: LETTERS PATENT to Robert Eastman, of Islington, in the County of
Middlesex, for the Invention of "IMPROVEMENTS IN CASTORS AND ANTI-
FRICTION ROLLERS."
Sealed the 16th January 1872, and dated the 18th July 1871.
PROVISIONAL SPECIFICATION left by the said Robert Eastman at
the Office of the Commissioners of Patents, with his Petition, on
the 18th July 1871.
I, ROBERT EASTMAN, of Islington, in the County of Middlesex, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
CASTORS AND ANTIFRICTION ROLLERS," to be as follows:-
:-
In my previous Patent No. 1689, dated 24th June 1865, I described
certain forms of castors, and my present Invention consists of improve-
ments upon the castors therein described.
For the purposes of my Invention I take a ball of a form as truly
spherical as possible, and constructed of a material as hard as possible,
such as hard wood, metal, ivory, bone, porcelain, earthenware, or glass,
but preferably of glass, colorless or ornamented with different colors,

page_text: and I place this ball within a suitable frame which is attached to the
lower end of the leg or foot of the piano, chair, table, or other article of
furniture to which the castor is to be applied. Directly over the centre
of the ball I fix in the frame described a piece of metal, glass, or other
substance sufficiently hard, part of which (which part I prefer to make
convex, but which may be either flat or concave) rests upon the ball,
upon which the weight of the leg or foot of the piano, chair, or other
article of furniture thus presses.
In my former Patent already referred to I described a ring of metal
or other suitable material which embraced the ball at or below its
horizontal diameter. But in my present Invention I form inside the
frame three or more projections or knobs above the horizontal diameter
of the ball, and I make them at such a distance apart horizontally that
when the convex piece first described is pressing upon the top of the
ball, not more than two out of the three or more projections or knobs
can touch the surface of the 'ball at the same time. By this arrange-
ment when the frame or castor is moved laterally the weight is imme-
diately upon the top of the ball, whilst one or two (and no more) of the
projections or knobs press against the upper hemisphere of the ball, and
keep it under the hard picce first described. In this construction it is
impossible for the ball to jam or become fixed. And by this Invention
the table, chair, piano, or other article of furniture, to the legs of which
the apparatus is attached, remains much more steady when at rest than
if the knobs or projections are at or below the level of the diameter of
the balls, inasmuch as the balls rest not only upon the hard piece above
them but also against one or two of the knobs or projections described.
In order to prevent the ball from dropping out of the frame if the chair
or other article of furniture is raised, I carry down three or more arms
from the upper part of the frame, and I curve these arms in below the
level of the diameter of the ball, so that the ball rests upon them if the
frame is raised, but I make their lower extremities (upon which the ball
rests in such case) at such a distance apart that the ball cannot touch
them when the frame is resting upon it, and when one or more of the
knobs or projections is touching it. And for antifriction rollers where
very heavy pressure has to be resisted by the ball I sometimes form the
three or more knobs or projections themselves of balls, which are
supported in precisely the same way as the balls in the apparatus first
described.

page_text: The accompanying Sheet of Drawings is in illustration of this
Invention.
Figure 1 is a section of a castor constructed according to this Inven-
tion; Figure 2 is a sectional plan; and Figure 3 is an elevation.
A is the ball described; B is the frame attached to the leg of a piano,
chair, table, or other article; C is a convex piece (which I sometimes
make flat or concave) attached to the frame B directly over the ball A.
The knobs or projections D, D, D, D, D, of which five are shewn, but of
which three or more may be used, are arranged above the level of the
centre of the ball A, and at such a distance apart that the ball can never
touch more than two of them at once; E, E, E, E, E, are arms which
are carried down from the frame B and are curved in, so that the ball A
rests on their extremities if the frame B is raised, but they are at such a
distance apart that they do not touch the ball when the frame and
convex piece C is resting upon the ball. The knobs or projections
D, D, D, D, D, are shown attached to the inside of the arms E, E, E, E, E,
but the frame B may be brought down sufficiently low for the knobs to
be formed upon it. The arms E, E, E, E, E, being open allow the
be of colored or ornamental glass or other hard
substance, to be seen between them; and when the frame B is made
ornamental these castors are peculiarly adapted for pianos, as the glass
ball A forms a perfect insulator with castor combined.
ball A, which may
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Eastman in the Great Seal Patent Office
on the 18th January 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
EASTMAN, of Islington, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of July, in the year of
our Lord One thousand eight hundred and seventy-one, in the thirty-fifth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Robert Eastman, Her special licence that I,
the said Robert Eastman, my executors, administrators, and assigns,
or such others as I, the said Robert Eastman, my executors, admi-
nistrators, and assigns, should at any time agree with, and no others,

page_text: from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN CASTORS
AND ANTIFRICTION ROLLERS," upon the condition (amongst others) that
I, the said Robert Eastman, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and
seals, should particularly-describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Robert Eastman, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement and accompanying Drawing :-
In the Specification of my previous Patent, dated June 24th, 1865,
No. 1689, I described certain forms of castors, and my present Invention
consists of improvements upon the castors therein described.
This Invention relates especially to that form of castor known as the
cup and ball" castor, and has for its object the making of such castors
in such manner that when applied to the legs of pianos, tables, chairs, or
other articles of furniture, much greater steadiness is attained when the
castors are at rest, whilst there is very little friction when they are
moving, and it is impossible that the balls of the castors can." jam,"
so as to make their revolution difficult or impossible. Castors con-
structed according to this Invention can be easily made ornamental in
appearance.
My Invention is also applicable to antifriction rollers where great
pressure has to be resisted, as herein-after described.
In order to carry out my Invention in making castors for the legs of
pianos, tables, chairs, or other furniture, I take a ball of a form as
nearly as possible spherical, and constructed of a hard material, such as
hard wood, metal, ivory, bone, porcelain, earthenware, or glass, but
preferably for most purposes of glass, either colorless or ornamented with
different colors. I place this ball within a suitable frame or socket
which is attached by 'screws, or in any of the methods ordinarily used
and practised, to the lower end of the leg or foot of the piano, table,

page_text: chair, or other article to which the castor is to be applied, and directly
over the centre of the ball I fix in the frame or socket a piece of metal,
glass, or other sufficiently hard substance, which rests upon the ball
upon which the weight of the leg or foot of the piano, table, chair, or
other article of furniture thus presses, and I prefer to make the piece
of hard substance described convex in the part which rests upon the
ball, but sometimes I make it either flat or concave. Inside the frame
or socket within which the ball is placed, as described, I place or make
three or more knobs or projections equidistant from one another, and
in a horizontal plane above the horizontal diameter of the ball, and I
make them at such a distance apart horizontally that when the hard
convex piece already described is pressing upon the top of the ball not
more than two out of the three or more knobs or projections described
can touch the surface of the ball at the same time. By this arrange-
ment when the frame or castor is moved laterally the weight presses
immediately upon the top of the ball, whilst one or two (and no more) of
the knobs or projections press against the upper hemisphere of the ball
above the horizontal plane, passing through its centre, and they thus
keep it under or very nearly under the centre of the hard piece which
presses upon it, and of the frame or socket. By arranging the knobs
or projections as described so as to be above the horizontal plane
passing through the centre of the ball it is impossible that the ball can
"jam," as it is sometimes liable to do, if they are arranged in a hori-
zontal plane at or below the centre of the ball. And by the arrangement
described great advantage in steadiness is attained when the castor and
piece of furniture is at rest, as the ball touches and supports not only
the hard piece above it, but also one or two of the knobs or projections
described. In order to prevent the ball from dropping out of the frame
or socket if the chair or other article of furniture, to the leg of which it
is attached, is raised, I carry down three or more arms from the upper
part of the frame, and I curve these arms in below the level of the
centre of the ball, so that the ball rests upon them if the frame or socket
is raised, but I make their lower extremities (upon which the ball rests
in such case) at such a distance apart that the ball cannot touch them
when the frame or socket is resting upon it, and it is touching one or
two of the knobs or projections. Sometimes instead of carrying down
arms as described I carry down the body of the frame for the same
purpose in the form of a ring, which I curve in below the level of the
centre of the ball, and I sometimes make ornamental openings in such

page_text: ring or frame, through which the ball, which I make ornamental, may
be seen.
I especially use castors so constructed for supporting the legs
of pianos, and the balls (which I prefer to make of glass for the purpose)
are not only ornamental castors, but also serve in the usual way for
what are called "insulators," to improve the tone of the piano.
In cases where I use balls as described as antifriction rollers for the
purpose of resisting very heavy pressures, I sometimes form the three
or more knobs or projections themselves of balls, which are supported
in precisely the same way as the principal balls in the apparatus first
described.
The accompanying Drawings are in illustration of my Invention.
Figure 1 is a section of a castor constructed according to my Inven-
tion, and having five knobs or projections and five arms; Figure 2 is a
sectional plan, and Figure 3 an elevation of the same. A is the ball as
described, upon which the weight rests; B is a frame or socket attached
to the leg of a piano, chair, table, or other article of furniture; C is a
convex piece (which I sometimes make flat or concave) attached to the
frame B directly over the ball A. The knobs or projections D, D, D, D, D,
are arranged above the level of the centre of the ball A, and at such a
distance apart that the ball can never touch more than two of them at
once. They are formed upon or attached to arms E, E, E, E, E,
which are carried down from the frame B, and are curved in, so that the
ball A rests upon their extremities if the frame B is raised, but they are
at such a distance apart that they do not touch the ball when the
piece C is resting upon the ball. The ball A I generally make orna-
mental, and it can be seen between the arms E, E. By the arrangement
described and shewn the knobs D, D, being above the level of the centre
of the ball A, the frame B remains steady, as it is supported at three
points, that is to say, the piece C and two of the knobs D.
Figure 4 shews a section, and Figure 5 an elevation of a larger castor,
in which the frame B is brought down over the ball A, and has the
three or more knobs or projections D attached to it. The lower edge of
the frame B is curved in below the centre of the ball A, so as to
support the ball when the castor is raised. Sometimes I make openings
in the frame B, through which the ornamental ball A can be seen, as
shewn at Figure 5.

page_text: Figure 6 shows a smaller castor made according to my Invention.
A is the ball; B is the frame which is attached to the leg of the
furniture by the screw F.
Figure 7 shews a similar arrangement, but the lower edge of the
frame B is shewn screwed in instead of bent over, as in Figure 6.
Figure 8 shews my Invention applied to a turntable. A is one of the
balls which supports the edge of the turntable B. Instead of knobs or
projections pressing upon the ball A, I use three or more smaller
balls D, D, arranged in positions similar to those of the knobs previously
described, and each of these balls D, D, is supported by knobs or
projections F, F, F, in the same way as the principal balls in the castor
already described.
In witness whereof, I, the said Robert Eastman, have hereunto set
my hand and scal, this Eighteenth day of January, in the year of
our Lord One thousand eight hundred and seventy-two.