IMPROVEMENTS IN CASTORS
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by the said Alexander Bell at the Office
of the Commissioners of Patents on the 25th April 1881.
ALEXANDER BELL, of the City and County of Edinburgh, North Britain,
"IMPROVEMENTS IN CASTORS."
This Invention relates to an improved construction of castor for chairs, tables,
and other articles of furniture, and for other similar use, and it is designed for giving
greater efficiency of the swivelling action and removal and renewal of the castor
proper, without unscrewing from and refitting to the furniture to which it is
applied.
The improved castor is made in two separate pieces, an upper part which consists
of a flat plate, or the usual socket for attachment to the leg of the table, chair, or
other piece of furniture, and the lower forked swivelling bracket piece carrying the
castor roller. The upper part is fitted or formed with a centre pin or stud, which
is preferably slightly tapered, and terminates at the lower end in a conical point.
This pin or stud fits in a corresponding socket in the centre of the swivelling forked
bracket or horns, and this socket may be formed of brass, iron, or other metal,
or it may be fitted with an internal liner of gun metal or suitable bearing
metal.
The two parts of the castor are secured or held together when fitted by means
of a pin or pins passing through the socket and entering a groove formed round
the centre pin, and this holding pin may be withdrawn to remove the swivelling
bracket or castor proper for renewal, without removing the plate or socket attached
to the table or other article.
The advantages of this new or improved construction of castor are the giving of
a freer swivelling action with equal or greater bearing power, while reducing
friction to a minimum in addition to facilitating the separation and renewal of the
upper stem or the lower socket swivelling part.
_ALEXANDER BELL, of the City and County of Edinburgh, North Britain.

page_text: and other articles of furniture, and for other similar use, and it is designed for
giving greater efficiency of the swivelling action and removal or renewal of the
castor proper without unscrewing from and refitting to' the furniture to which it is
applied.
And in order that my said Invention and the manner of performing the same
may be properly understood, I have hitherto appended for that purpose a Sheet of
explanatory Drawings, to be hereinafter referred to, and representing modifications
of my improved castors. The same reference letters are used in these Drawings to
indicate the same parts in the different Figures.
Figures 1 and 2 are side and front elevations of one modification of the improved
castor, the former Figure being partly in section; Figures 3 and 4 are similar views
of a slightly different modification of the castor, and Figures 5 and 6 are an elevation
and inverted plan of the upper part of the castor which is attached to the leg or
supporting member of the furniture.
Referring to these Drawings the improved castor is made in two separate pieces,
an upper part which consists of a flat plate A, or the usual socket for attach-
ment to the leg of the table, chair, or other piece of furniture, and the lower forked
swivelling bracket piece B, B', carrying the castor roller C. The upper part A is
fitted or formed with a centre pin or stud A', which is preferably slightly tapered,
and terminates at the lower end in a conical point or frustrum of a cone.
This pin
or stud A¹ fits in a corresponding socket B¹ in the centre of the swivelling forked
bracket or horns B; and this socket may be formed of gun-metal, brass, iron, or
other metal, either in a piece with or fixed to the horns B, or it may be fitted with
an internal liner of gun-metal or suitable bearing metal on which the centre
stud A¹ bears. The two parts A, B, of the castor are secured or held together
when fitted by means of a pin b or pins passing through the socket and entering a
groove a formed round the centre pin or stud A', the pin being either screwed and
fitted with its point entering the groove a, as in Figures 1 and 2, or entered to lie
longitudinally in the groove, as shown in Figures 3 and 4. The holding pin b may
be withdrawn to remove the swivelling bracket or castor proper B, B1, for renewal,
without removing the plate or socket A, A¹, attached to the table or other
article.
The advantages of this new or improved construction of castor are the giving of
a freer swivelling action with equal or greater bearing power, while reducing friction
to a minimum in addition to facilitating the separation and renewal of the upper
stem or the lower socket swivelling part.
Having thus described my said Invention, and the manner of performing the
same, I have to state that what I claim as the Invention secured to me by the
herein before in part recited Letters Patent is, the construction of a furniture
castor in two separable parts A, B, and with a centre stud or pin (A¹) in the upper
part bearing on a socket B' in the lower part, the parts being secured by a holding
pin or pins (b), substantially as herein described in reference to the accompanying
Drawings.
In witness whereof, I, the said Alexander Bell, have hereunto, set my hand
and seal, this Tenth day of September, in the year of our Lord One
thousand eight hundred and eighty-one
ALEXANDER BELL. (L.S.)