Improvements in Vacuum Brake Apparatus suitable for Railway Vehicles.
Year: 1895

page_text: Date of Application, 25th Feb., 1895
Complete Specification Left. 25th Oct.. 1895-Accepted, 30th Nov., 1895
PROVISIONAL SPECIFICATION.
Improvements in Vacuum Brake Apparatus suitable for Railway
Vehicles.
I, ALEXANDER SPENCER, of 77 Cannon Strect, in the City of London,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention of improvements in vacuum brake apparatus has reference to the
vacuum chambers and elastic diaphragms used in such apparatus and has for
object to obviate the constant working and strain upon the diaphragins such as
obtains with the elastic diaphragms heretofore usually employed in which the
construction is such that the diaphragms are turned or bent inside out each time
the brakes are put on and taken off. For this purpose I construct the elastic
diaphragm of two centrally perforated sheets of elastic or flexible material such as
india rubber or leather, one of which is secured at its outer periphery to a movable
plate arranged within the vacuum chamber and fixed to a rod that is connected
secured at its outer
with the brake block carrying appliances whilst the other
periphery to a ring or perforated plate fixed to the vacuum chamber, or it may be
to the chamber itself, the central portions of the two sheets being secured together
between suitable washers or perforated plates. The arrangement is such that the
diaphragm when expanded is of approximately double V or angular shape in
cross section. Normally the diaphragm is in the collapsed condition, so that the
plate carried by the brake operating rod and the elastic or flexible sheets are near
together and to one end of their containing chamber; on air being admitted so as
to expand the diaphragm, the brakes will be applied. Two or more such
diaphragms may be connected together at their adjacent outer edges; the outer
edges at the ends of the compound diaphragm thus formed being then connected
to the aforesaid movable plate and fixed ring or perforated plate or part of the
vacuum chamber. In this case the pair of connected outer edges of the compound
diaphragm, or each such pair when there are more than one, may be strengthened by
a perforated plate or frame arranged to slide on or in a suitable bearing. In one
arrangement the vacuum chamber is made in three transverse parts and is
provided at each end with a single elastic diaphragm constructed as described.
The outer end of each diaphragm is secured to a ring fixed between the central and
one of the end portions of the chamber, and the inner end of each brake operating
rod is extended inward and supported in a bearing carried by the central portion
of said chamber, which as well as the end portions, is formed with a hole for
passage of air.
As will be obvious elastic diaphragms and vacuum chambers as described
can be variously modified without departing from the essential features of my
invention.
Jahmo 1805

page_text: COMPLETE SPECIFICATION.
Improvements in Vacuum Brake Apparatus suitable for Railway
Vehicles.
1, ALEXANDER SPENCER, of 77 Cannon Street, in the City of London, Engineer,
do hereby declare the nature of this invention and in what manner the same
to be performed to be particularly described and ascertained in and by the following
statement:—
This invention of improvements in vacuum brake apparatus has reference to the
vacuum chambers and elastic diaphragms used in such apparatus and has for
object to obviate constant working and strain upon the diaphragms such as obtains
with the elastic diaphragms heretofore usually employed in which the construction
is such that the diaphragms are turned or bent inside out each time the brakes are
put on and taken off. For this purpose I construct the elastic diaphragm of two
centrally perforated sheets A, A' (see Figs. 1, 2 and 5 of the accompanying
illustrative drawings) of elastic or flexible material such as india rubber or leather,
one of which A is secured at its outer periphery to a movable plate B arranged
within the vacuum chamber C and fixed to a rod D that is connected with the
brake block carrying appliances whilst the other A¹ is secured at its outer periphery
to a ring or perforated plate E fixed to the vacuum chamber C, or it may be to the
chamber itself (Fig. 3); the central portions of the two sheets A, A' being secured
together between suitable washers or perforated_plates F, F1, F2. The arrange-
ment is such that the diaphragm when expanded (Figs. 2 and 5) is of approximately
double or angular shape in cross section. Normally the diaphragm is in the
collapsed condition so that the plate B carried by the brake operating rod and
the elastic or flexible sheets A, A¹ are near together and to one end of their
containing chamber (see Fig. 1); on air being admitted so as to expand the
diaphragm (Figs. 2 and 5), the brakes will be applied. Two or more such
diaphragms may be connected together at their adjacent outer edges; the outer
edges at the ends of the compound diaphragm thus formed being then connected to
the aforesaid movable plate B and fixed ring or perforated plate E or part of the
vacuum chamber. Fig. 4 illustrates an arrangement in which the compound
diaphragm is formed by connecting together two diaphragms like that represented
in Figs. 1 and 2. In this case the pair of connected outer edges of the compound
diaphragm or each such pair when there are more than one, may be strengthened
by a perforated plate or frame arranged to slide on or in a suitable bearing. Such
a plate is shown at G, arranged to slide on rod D.
In the arrangement represented in Fig. 5 the vacuum chamber is made in three
transverse parts C¹, C2, C³ and is provided at each end with a single elastic
diaphragm A, A¹ constructed as described. The outer end of each diaphragm is
secured to a ring E fixed between the central and one of the end portions of the
chamber, and the inner end of each brake operating rod D, D¹ is extended inward
and supported in a bearing H carried by the central portion C2 of said chamber,
which, as well as the end portions, is formed with a hole a for passage of air.
As will be obvious elastic diaphragms and vacuum chambers as described can be
variously modified without departing from the essential features of my invention.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The hereinabove described construction of elastic diaphragm for vacuum
brake apparatus wherein there are two centrally perforated or annular sheets of
elastic or flexible material such as india rubber or leather, one of which is secured
at its outer periphery to a movable plate arranged within the vacuum chamber and

page_text: fixed to a rod connected with the brake block carrying appliances whilst the other
is secured at its outer periphery to a ring or perforated plate fixed to the vacuum
chamber or to the chamber itself and the central portions of the two sheets are
secured together between suitable washers or perforated plates.
2. An elastic diaphragm for vacuum brake apparatus comprising four or more
centrally perforated or annular sheets of elastic or flexible material such as india
rubber or leather one end sheet being secured at its outer periphery to a fixed ring
or annular plate or to a part of the vacuum chamber and the other end sheet being
secured at its outer periphery to a movable plate located within the vacuum
chamber and the intervening inner and outer peripheries of the elastic sheets being
secured together between suitable washers or perforated plates substantially as
described.
3. My improved vacuum brake apparatus as shown in and described with
reference to Fig. 4 of the drawings.
4. Vacuum brake apparatus substantially as described with reference to and
illustrated in Fig. 5 of the drawings.
D
1
cou 1005