Improvements in Collectors for Electric Tramways and Railways.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in Collectors for Electric Tramways and Railways.
ROBERT HENRY SMITH 124 Hagley Road Birmingham Warwickshire I do hereby
declare the nature of this invention to be as follows:-
I propose to use an improved collector in which the moveable parts pressed
against the conductor by springs, are of small weight and are of no greater length
than is necessary to allow them to accomodate the contact surface to the inequalities
in level of the conductor and to its deviations in plan from parallelism to the
tram-rails. With a stiff rail these inequalities being minute the moveable parts
need be only an inch or two in length. With a wire suspended between distant
supports, the length required depends upon the sag allowed to the wire. The
contact surface is made one or more inches in length to ensure ample electric
contact, and it is composed of a number of separate parts each pressed against the
conductor by an independent spring of small size. These parts may be a series of
trolley wheels or rollers of small diameter; they may be the separate copper spring
strips of a brush; or they may be a series of carbon blocks. The oscillation of the
contact surface extends throughout a very small mass only of the collector, the
movement allowed for sag of a suspended conductor and for deviations in plan at
crossings, curves and turn-outs, extending throughout a greater mass and being
operated by a secondary spring. The bracket or carrier by which the car carries
the collector is made rigid and strong and is rigidly attached to the car. Similar
contact is made between motor and rail for the return, the car wheels not being
used for this purpose.
Dated this 24th day of Santamba 1900
COMPLETE SPECIFICATION.
Improvements in Collectors for Electric Tramways and Railways.
I, ROBERT HENRY SMITH of Ellerslie, Brunswick Road, Sutton, in the County of
Surrey, Professor of Engineering and Consulting Engineer, 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 :-
The invention relates to improved collectors of electric current from the feed
line of electric tramways and railways fed either by overhead wire or wires or by
rods or rails or strips laid in a slotted conduit or laid in any part of a tunnel or upon
the surface of the ground.
The object of the invention is to ensure close continuous and uninterrupted
ΓΥ

page_text: contact between the collector carried by the car and the feed line and thus to
suppress or greatly diminish sparking at this contact. For this purpose I use
several forms of collector in which the moveable parts pressed against the fixed
conductor by springs are of small weight and are of no greater length than is
necessary to allow them to accomodate the, contact surface to the inequalities
in level of the conductor and to its deviations in plan from parallelism to the
tram-rails. With a stiff rail these inequalities being minute the moveable parts
need be only an inch or two in length. With a wire suspended between distant
supports the length required depends upon the sag allowed to the wire. The
contact bearing is made one or more inches in length to ensure ample electric
contact and it is composed of a number of separate parts each pressed against the
conductor by an independent spring of small size. These parts may be a series
of trolley wheels or rollers of small diameter, they may be the separate copper
spring strips of a brush or they may be a series of carbon blocks. The oscillation
of the contact surface extends throughout a very small mass only of the collector,
the movement allowed for sag of a suspended collector and for deviations in plan
at crossings, curves and turn outs extending throughout a greater mass and being
operated by a secondary spring. In the accompanying drawings Figures 1, 3 and 6
are respectively side elevations, end elevation and plan in full size of an arrange-
ment in which my invention is carried into effect while Figure 5 is a sectional
elevation corresponding thereto and Figures 2, 4, 7 and 8 are detail views;
Figures 9, 10 and 11 are respectively part elevation plan and sectional elevation of
a modified arrangement in which my invention is carried into effect.
In Figures 1, 2, 3, 4, 5, 6, 7, and 8 are shown a construction of this improved
collector in which three small trolley wheels are employed. This number or two :
only may be used for any ordinary tram-car while for the motor car of a railway
train 4, 5, 6, or even 8 wheels may be used according to the amount of current to
be taken up. The trolley wheels A A A are mounted on hardened steel pins B
whose ends are squared and fit into square recesses stamped in the steel side arms C.
Between these arms and each wheel lie two rubber or other elastic washers.
Between the washers and the wheel lie the two ends of the thin copper strip K
which brings the current up to the two flat faces of the wheel. The three strips
KKK for the three wheels are connected by the longitudinal strip L which is
bent as shown in Fig. 1 between each wheel in order that it may allow free separate
motion to each of the wheels. This strip L is connected to the cable M which
takes the current to the motor. The arms C are mounted upon the pins EEE
which can turn in their bearings in the bosses G G G. Round each pin E passes
a coiled spring F the ends of which are fastener to the arms C while its middle
is fastened to the boss G. These coiled springs rotate the arms round the pin E
and thus press the trolley wheels against the line. The angle through which the
arms C may turn on the pins E is limited by stop pins fixed in G as shown in
Fig. 1. On the carrier G are cast two bosses through which passes the pin I. This
pin I passes through the boss H and thus makes a hinge joint between the trolley
carriage G and the end of the trolley pole. A strong coiled spring J passes round.
the pin I and is connected at the ends to the bosses on G and at its middle to H
thus giving a certain amount of elastic freedom to G enabling it to swing by a
small angle round H to either side of its normal position. The boss H swivels
upon the trolley pole in the usual manner.
Figures 9 10 and 11 show a small slider block which may be used instead of the
trolley wheel. Three or more of these are mounted on arms C in precisely the same
manner as the trolley wheels shown in the previous figures. P is the block of
hard contact carbon which is slipped endwise into the copper block Q. The
carbon block slides in contact with the line and the rubbing friction is prevented
from drawing it out of P by the plate R which is screwed on the end surface of P.
The three copper blocks Q mounted on one carriage are electrically connected by
a strip L similar to the strip L of Figure 1. For the elastic support either of
rollers or of sliding blocks I sometimes make the arms C C themselves flexible and

page_text: I then suppress the two pin joints I and E and also the two coiled springs F and J.
Figures 12 and 13 show in front and side elevations one form of this construction
in which each arm.C is made of strip spring steel. At each extremity is stamped
a recess into which is inserted the end of the pin B of the contact piece the recess
being square when a trolley wheel is used and round when a sliding block is used.
Each arm is made about three inches long. Throughout about one inch length
from the contact end the two strips have their flat sides parallel to each other and
at right angles to the contact piece pin. Each strip is then given a quarter twist
so as to bring the flat sides of the remainder of the length of the two arms into the
same plane and parallel to the pin of the contact piece. The lower ends of the
strip are screwed or otherwise clamped to a plate rigidly fastened to the end of
the pole.
In Fig. 14 the two arms C C are formed of sound hard steel wire one length of
wire forming both arms. The outer ends are coiled round the ends of the pin B
of the contact piece the coil of wire forming the bosses in which the pin takes its
bearing. At the lower ends the wire is bent as shown and lies in a groove milled
out of the screw plug, S. This plug is screwed into a boss on the plate rigidly
fastened to the end of the pole.
In both these designs Figs. 12 and 13 and Fig. 14 the contact piece can be with-
drawn for renewal or repair by simply bending one of the arms C. Also in both
of them since each arm can bend in either of two directions and as the two arms
of a contact piece can bend with unequal deflections the arrangement amounts to
allowing a limited range of swivelling of the contact piece, that is it is given
restricted elastic freedom of motion in three directions.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. For collecting the current from the feed line of an electric tramway or railway
a collector composed of three or more separate parts or contact pieces each separately
pressed by an independent spring upon the feed line so that if one part momentarily
leaves the line the other parts will still make good electric contact each contact
piece being either a rolling or sliding piece substantially as herein before described
and illustrated.
2. In current collectors making each contact piece of small mass so that it will
respond to the spring pressure employed to force it against the line by a quick
movement as hereinbefore set forth.
3. The use of a number of separate contact pieces the number of them being
proportioned to the magnitude of the current to be collected instead of one piece for
the purpose of reducing the cost of manufacture and of renewal as herein set forth.
Dated this 26th day of June 1897
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham,.Agents.