AN IMPROVED COMPOUND SPIRAL SPRING
Year: 1886

page_text: Date of Application, 16th Apr., 1886.
Complete Left, 15th Jan., 1887.
Complete Accepted, 15th Feb., .1887.
We, BENJAMIN FREDERICK COCKER, Manufacturer, and JOHN BISHOP, Contractor,
both of the Nursery Street Wire Mills, Sheffield in the County of York do hereby
declare the nature of our said invention for AN IMPROVED COMPOUND SPIRAL SPRING
to be as follows:-
Our invention which refers more particularly to the construction of compound
spiral springs, is an improvement upon the compound spiral spring as described in the
specification of our Patent No. 13499, 1884, and though especially adapted for the
bearing springs of Tramcars, and similar purposes, it may be used for any suitable
purpose such as buffer and drawbar springs.
It consists in the combination of an external and an internal metallic spiral spring,
with an intermediate tubular layer of vulcanised rubber attached either to the internal
spring, or to the external spring, or to both as may be desired.
The steel of which the springs are made may be of any desired section, but we
prefer that the internal spring shall have a flat inner face, to form a smooth surface
for the drawbar to work upon; and upon and around the internal spring a tubular
layer of rubber is formed and vulcanised, the diameter of which is made to correspond
with the internal diameter of the external spring into which it is forced.
We find in practice that a good result is obtained if the inner spring is made of
halfround steel with the flat inside, and the outer spring of round steel, the last coil
at each end being tapered so as to produce a flat ended spring.
ROBT. F. DRURY,
Agent for the Applicants.

page_text: We BENJAMIN FREDERICK COCKER Manufacturer, and JOHN BISHOP Contractor
both of the Nursery Street Wire Mills, Sheffield, in the County of York 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:-
Our invention which refers more particularly to the construction of compound
spiral springs, is an improvement upon the compound spiral spring such as described
in the Specification of our Patent No. 13499, 1884, and though especially adapted
for the bearing springs of Tramcars, and for other similar purposes, it may be used
for any purpose to which such springs are or may be applicable, such as for example
Buffer and Drawbar Springs.
The sheet of drawings annexed shows very clearly the construction of a spring
constructed according to our invention.
Fig. 1, is a sectional plan of a compound spring made on our improved plan.
Fig. 2, elevation of the internal spring.
Our invention consists in the combination of an external and an internal spiral
metallic spring with an intermediate tubular layer of vulcanised rubber, attached
either to the internal spring, or to the external spring, or to both springs conjointly
as may be found desirable."
A is the external spiral spring, B is the internal spring, and C is the rubber.
The steel of which the springs are made may be of any suitable cross-section, but
we prefer that the internal spring B, shall have a flat inner face as shown in Fig. 1,
so as to present a smooth surface for the drawbar to work against, and upon and
round the internal spring a tubular layer of rubber C, is formed by any suitable
means, and then vulcanised, the outside diameter of the said rubber being made to
correspond with the internal diameter of the external spring into which it is forced.
We find in practice that a good result is obtained if the inner spring is made of
half round steel with the flat part inside, and the outer spring of round steel, the last
coil at each end being taper and flat so as to produce a flat ended spring.
Having now particularly described and ascertained the nature of our invention, and
in what manner the same is to be performed, we declare that what we claim, is:
--
A compound spiral spring consisting of an outer spring (such as A) an inner spring
(such as B) and an intermediate filling of vulcanised rubber, substantially as herein
described and illustrated.
ROBT. F. DRURY,
Agent for the Applicants.