Improvements in Current Collectors for Overhead Electrical Conductors.
Year: 1894

page_text: Date of Application, 25th Sept., 1894
Complete Specification Left, 25th June, 1895-Accepted, 27th July, 1895
[Communicated from abroad by Messrs. SIEMENS & HALSKE, of Berlin, in the
German Empire, Electrical Engineers.]
Improvements in Current Collectors for Overhead Electrical
Conductors.
We, SIEMENS BROTHERS & Co. LIMITED of 12 Queen Anne's Gate,
Westminster, in the County of Middlesex, Electrical Engineers, do hereby declare
the nature of this invention to be as follows:-
This invention relates to the collector employed in electrical railways or tramways
for conducting the electric current from an overhead wire to the vehicle running on
the track below. The object of the invention is to mount the rod of the collector,
which extends obliquely up from the vehicle to the wire, in such a manner that,
when the movement of the vehicle is reversed, this rod can freely pass over to an
oppositely inclined attitude, this mounting having the effect also of allowing the
collector to maintain good contact with the wire notwithstanding oscillations of the
vehicle on its springs or variations in the height of the wire above the track. For
this purpose, the collector rod is jointed to a horizontal lever arm which is mounted
on the vehicle so as to lie longitudinally.
From the rod, at its lower end where it is jointed to the lever arm, project two
short arms, the one inclined a little upwards and the other equally inclined down-
wards, and these are connected by slotted links to a spring, so that the collector
rod, when free, held by this spring in a vertical attitude, but can be inclined to
the one side or the other of the vertical. The lever arm to which the rod is
jointed is free to move a certain distance up and down between stops, and is held
up by a spring of sufficient strength to support the weight of the moveable parts
and to give the collector a certain amount of pressure against the wire. In order
to steady the appliance laterally, the lever arm is duplicated, consisting of two
parallel arms, the rod is also duplicated as well as the springs. Instead of a single
lever arm or a pair of parallel arms, a couple of arms or duplicate arms forming a
toggle or pair of parallel toggles may be employed, the collector rod being jointed
to the middle of the toggles, and carrying on an extension at its lower end an arm
strained by springs so as to hold the rod when free in a vertical attitude. The
toggles are mounted at the one end on a bracket, at the other end on a vertical
radial link, and are strained by a spring or springs so as to urge the collector rod
upwards, pressing it against the wire.
The contact with the wire may be made by clips, rubbers or rollers carried by
the rod.
Dated this 25th day of September 1894.
ABEL & IMRAY,
Agents for the Applicants..

page_text: Improvements in Current Collectors for Overhead Electrical
Conductors.
We, SIEMENS BROTHERS & CO. LIMITED, of 12 Queen Anne's Gate,
Westminster, in the County of Middlesex, Electrical Engineers, 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:-
This invention relates to the collector employed in electrical railways or tramways
for conducting the electric current from an overhead wire to the vehicle running on
the track below. The object of the invention is to mount the rod of the collector,
which extends obliquely up from the vehicle to the wire, in such a manner that,
when the movement of the vehicle is reversed, this rod can freely pass over to an
oppositely inclined attitude, this mounting having the effect also of allowing the
collector to maintain good contact with the wire notwithstanding oscillations of the
vehicle on its springs or variations in the height of the wire above the track.
For the above purpose the collectors are constructed so as to have spring action
in two directions as we will describe with reference to the accompanying drawings.
Fig. 1 shews a side view and Fig. 2 a front view of one arrangement.
The arm P of the collector is fixed on a spindle W on which is also fixed a
forked lever H, each arm of which is connected by a slotted link Z1 Z2 to one end
of a spring F whose other end is adjustably attached to a standard S on the vehicle,
so that the spring F tends to maintain the rod P with its collector in the vertical
middle position, and consequently, when the rod P is in an inclined position, the
spring causes the collector to be pressed with a certain force against the overhead
conductor.
The bearings LL of the spindle W are mounted on a horizontal lever or
frame G which is pivotted at D to the standards S while the other end is supported
by two pendent springs F¹ fixed at the upper ends to standards St and at the lower
ends to the frame G, a stop A on which, in bearing against stops on the standard S¹
limits the upward and downward motion of G. The arm P with the contact bar is
consequently held in the position shewn, by the springs F¹ which allow of a certain
up and down motion thereof, so that, assuming the arm P to be inclined in one
direction while the vehicle is travelling, as shewn at Fig. 3, then if the motion of
the vehicle be reversed, the arm P will be able to assume first the vertical position
in pressing downwards the frame G as shewn at Fig. 34, and it will then be brought
into the opposite inclined position as shewn by the dotted lines at Fig. 3, the
frame G being then raised again by the springs F¹.
This arrangement is of particular advantage when the change in the direction
of motion takes place at a point near a rigid support of the overhead conductor,
and where consequently the latter could not be raised up sufficiently to allow the
rod P to assume the vertical position if it were not provided with the above
described vertical play. This vertical motion is also of advantage for preventing
the rebounding of the contact bar from the conductor and the consequent sparking,
which frequently takes place with present constructions in which no such vertical
spring action is provided at the bottom of the rod P.
The vertical motion of the body of the vehicle upon its wheel axles required
hitherto to be compensated for by causing the arm P of the collector to turn more
or less on its axis W, the necessary amount of such turning being the greater, the
nearer the arm P is to the vertical position. But as the spring F acts on the
arm P in a line which passes very close to the pivot, the turning moment thereof
is small, while the moment of inertia of the support and collector is comparatively
great, from which it results that the arm does not turn with sufficient rapidity under

page_text: the action of the spring for causing it always to remain in contact with the con-
ductor when the body of the vehicle sinks suddenly on its springs, and consequently
the collector, in leaving the conductor causes sparking. By providing for the
vertical motion of the bearings L, as above described, a second means is provided
for compensating for vertical oscillations of the vehicle body, which is independent
of the slow turning motion of the arm P. The springs F1, which are so arranged
as to balance the weight of the arm P with its collector, the bearings L, and the
frame G and in addition to exert a certain upward pressure thereon, operate with a
considerable leverage relatively to the pivot D and thus enable an upward motion
of the collector to be effected more rapidly than is possible by the turning motion
of the arm P alone.
The described construction is applicable not only to sliding collectors as described
but also to roller collectors, or clips. In the case of roller collectors however the
friction of the roller against the conductor is not sufficiently great to insure the
automatic reversal of the arm P on the reversal of the vehicles motion.
This difficulty may be readily overcome in the following manner.
A cord is so
attached to the contact support P that by exerting a pull upon it, the support is
pressed more firmly against the conductor, and the end of this cord is led to the
driver's platform, so that if the direction of motion is to be reversed the driver
pulls at the cord until the frictional resistance between the roller and the conductor
is increased to such an extent as to cause it to operate in the same manner as the
frictional collector bar.
Figs. 4 to 7 shew a somewhat modified construction of the yielding spring support
for the contact arm. In this case the contact arm is carried by spring bearings L
so arranged that, firstly, on reversing the direction of motion, the contact arm is
enabled to move more readily from the one inclined position through the vertical
position into the opposite inclined one, and secondly, the contact between the
contact bar and conductor is effected in a better manner than can be done by the
radial position of the arm alone.
Figs. 4 and 5 shew respectively a side view and front view of the apparatus with
the parts in the position when the arm P is only acted upon by the springs ;
Fig. 6 shews the arm P in its vertical position during the reversal of motion,.
when the support thereof is pressed downwards;
Fig. 7 shews the arm in the inclined position.
The arm P carried by the spindle W is acted upon by two symetrically
arranged groups of springs F acting on a lever H on the spindle W, thus tending
to maintain the collector arm in the vertical position, and consequently pressing the
collector against the conductor when the arm is inclined. The spindle W is carried
in bearings L that form part of the two armed lever G and the one armed lever G¹,
which are thus pivotted together, forming a kind of toggle frame that is supported
on the one side by a pivot D on fixed standards S and on the other side by
pivotted standards S'. The lever G has an extension on which act strong
springs F which thus tend to raise the toggle frame and consequently the contact
arm, but allow this to be depressed on the reversal of motion.
The points of attachment AA of the lever H are so arranged that the turning
moment of the springs F exerted on the arm P is greatest when the arm is nearly
vertical as at Fig. 7, so as, in acting together with the force tending to raise the
spindle W, to insure a good contact between the contact bar and the conductor.
Instead of supporting the toggle frame by a pivotted standard on one side as
described, both supports might be fixed and the frames be made with slotted con-
nections to allow of the downward motion.
The upward motion of the frames GG' might be assisted by providing the
frame G with extensions and spring F¹ similar to those of G, or the frames may
be constructed as elbow levers, the downward extended arins of which are connected
to opposite ends of one and the same set of springs.
The last described construction of the collector arm has the advantage over that
first described in affording the collector greater stability against lateral oscillations,

page_text: and in being of more simple construction. It can also be used with roller collectors
instead of with a frictional contact bar.
Figs. 8 and 9 shew respectively a side view and front view of a still farther
simplified and lighter construction of the apparatus. Instead of the arm P being
framed or double, as in the previous arrangements, it is formed as a single rod,
which is fitted with its lower end into a socket P' on an axis W rotatably mounted
in bearings L fixed on bars G2 carried by spring supports F fixed to the car body.
The axis W has arms H that are connected by slotted links Z to springs F. the
other ends of which are adjustably attached to the turned-up ends of the bars G²,
the action of these parts in tending to maintain the arm P in the upright position
being the same as described with reference to the first construction, while the
vertical spring motion is afforded by the spring supports F².
The loop shaped contact bar is secured by a socket P³ to the upper end of the
rod P, which may be either of tubular steel, wood or bamboo.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what
we claim is :-
1. In current collectors for electric railways or tramways with overhead con-
ductors, supporting the pivots of the arm that carries the current collector by
means of horizontal and vertical springs so arranged as to both hold the arm with
elastic action in the inclined position and to allow its support to be depressed when
it passes from one inclined position to the opposite inclined position on the reversal
of the direction of motion, substantially as described.
2. A current collector of the kind referred to in the first claim wherein the
spring supports are arranged as described with reference to Figs. 1 2 3 and 34 of
the drawings.
3. A current collector of the kind referred to in the first claim wherein the
spring supports are arranged as described with reference to Figs. 4 to 7 of the
drawings.
4. A current collector of the kind referred to in the first claim, wherein the
spring supports are arranged as described with reference to Figs. 8 and 9.
Dated this 25th day of June 1895.
ABEL & IMRAY,
Agents for the Applicants.