Improvements in and relating to Casters.
Year: 1894

page_text: Date of Application, 11th Sept., 1894-Accepted, 13th Oct., 1891
COMPLETE SPECIFICATION.
Improvements in and relating to Casters.
I, LEMI BRADLEY DENTON, a citizen of the United States of America,
residing at 525 East Fulton Street, in the City of Grand Rapids, in the County of
Kent and State of Michigan, one of the United States of America, Well Con-
tractor, 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 :-
My invention relates to improvements in caster attachments for use in connection
with tables, beds, chairs and the like, and it consists in an improved form of caster
particularly distinguishable by the form of the head of the spindle which is used,
which will be hereinafter fully described and particularly pointed out in the
claims.
The object of my invention is to provide a caster attachment which can be
readily and easily attached to and detached from articles of furniture, which will
be strong, durable and inexpensive, and which will be so constructed as to render it
impossible for the caster to drop out while the piece of furniture to which it is
attached is being moved from one place to another.
Heretofore casters have been made which make use of a cylindrical socket, which
is inserted into the legs of the article of furniture to which it is desired to attach
the caster; and the caster itself has been formed with a more or less cylindrica
spindle, which is inserted into the socket and there held. Among the means which
have been devised for holding the spindle in place is that of forming the end of the
spindle with a bulbous head, and slitting the end of the spindle a short distance
down, thus securing a spring pressure of the semi-bulbous heads against the sides
of the socket; or, in case the spindle is long enough to permit the semi-bulbous
heads to be inserted beyond the end of the socket, to cause the said heads to spring
outward and strike against the end of the socket.
Both of these constructions have been found to be objectionable because of the
insecurity of the holding effect thus produced, and because, to secure any holding
effect at all, it is necessary to slit the head of the spindle two or three times, and
thus materially weaken the same and diminish its durability.
In accomplishing the above stated object of my invention I make use, in
accordance with the prior art, of a cylindrical socket, and mount the caster wheel
upon a bifurcated hanger, from the top of which projects a spindle of a length a
little greater than the socket which I use, having a bulbous head slitted down from
its end a short distance; but I obviate the difficulty which has hitherto been
present of providing means for holding the spindle in place, which will render it
impossible for the caster to drop out while the piece of furniture to which it is
attached is being moved from one place to another, by flattening the bulbous head
on a plane at right angles to the plane of the slit. The increased spring power
gained by thus forming the bulbous head will be hereinafter fully considered, but
it may here be briefly stated, that it arises from the fact that on account of the
form of the head of the spindle, it is not necessary to limit the size of the bulbous
head by the diameter of the spindle socket, but by the diameter of the head on the
plane transverse to the plane of bifurcation.

page_text: My invention is fully represented in the drawings which accompany and form a
part of this Application, in which the same reference letters refer to the same
or corresponding parts, and in which-
Figure 1 is a side elevation of my caster attachment, the socket carrying the
spindle and the supporting ferrule being shown in section.
Figure 2 is a top plan view of my-caster attachment, showing the divided head
of the spindle, the flattened sides of the separate parts of the same, and the
supporting upturned flange with serrated edge.
.
Referring to the drawings, and first to Figure 1, A represents the bifurcated
hanger which carries the caster wheel, part of which is formed into an upwardly
extending spindle A', the body of the spindle which is above the hanger proper,
is provided with the shoulder a against which the lower end of the socket B rests.
A is the upper end of the spindle, and as shown it is slightly tapering until it
terminates with the bulbous head E. This upper end of the spindle is slitted
vertically for a portion of its length, forming the semi-bulbous heads e e and the
branches a' a'. Transverse to the plane of bifurcation the semi-bulbous heads are
flattened, forming flattened sides et e¹. As it is in thus forming the head of the
spindle that my invention resides, I will now describe specifically the reason
therefor, and the effects thereof, first mentioning that the cylindrical socket B,
(which is of any required length and diameter, is open at both ends, and has formed
on its lower end the flange b, which supports the upturned flange C having a
serrated edge,) is inserted into the leg of the article of furniture to which it is
desired to attach the caster.
As will be seen in the drawing, the spindle is somewhat longer than the cylin-
drical socket B, the greater length being equal to the length of the bulbous head of
the said spindle. The aperture in the leg or standard of the article of furniture
must also be made somewhat longer or deeper than the length of the socket B, so
that the head E of the spindle may have free movement. When the caster is to be
attached to the piece of furniture, the spindle is inserted in the socket B, until the
bulbous head of the same passes the upper or inner ends of said socket, which
will be indicated by a snapping sound. The increased spring holding effect thus
obtained may best be understood by referring to the present construction of caster,
and then by comparing with such construction my improved construction.
According to the present construction of caster, in which the end of the spindle
is made bulbous, and is slitted vertically two or more times, it is impossible to insert
into the cylindrical socket a head larger than the inner diameter of said socket.
If, therefore, the semi-bulbous heads are formed without the flattened sides, the
diameter of the upper end of the spindle is determined by the diameter of the
same on the plane of bifurcation. The spring effect obtained by such bifurcation
would be very small, and it would be necessary to have the upper end of said
spindle fit very closely to the socket into which it is to be inserted, in order that
the caster may be held in position when finally in place.
If, however, the semi-bulbous heads be flattened on a plane transverse to the
plane of bifurcation, as is the case in my construction, the diameter of the head on
the plane of bifurcation may be disregarded, and care need only be taken to make
the diameter on the plane of the flattened sides sufficiently less than the inner
diameter of the socket to insure an easy entrance of the spindle. The diameter
of the bulbous head may be chosen so large that it will be necessary to spring
together the two bifurcated portions of the same in order to secure its insertion
into the socket. The holding effect thus obtained is very positive. The head of
the spindle divided and flattened as described, springing out and resting upon the
upper end of the socket, forms a sufficient bearing to hold the caster wheel in place
while the article of furniture to which it is attached is raised, or is being taken
from one place to another. The spindle itself has a free movement, and can be
readily and easily inserted into and detached from the leg of the article of
furniture.

page_text: It is to be noted that in the construction thus described-and this is an important
feature of my invention, the spindle is not materially weakened, nor is the
resiliency of its separate branches affected.
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 :
In a caster attachment, the combination with the socket, of a spindle having an
enlarged head flattened upon two opposite sides and slitted vertically at right
angles to said flattened sides, substantially as described.
Dated this 11th day of September 1894.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.