Improvements in Trolley Standards used on Cars or Wagons Electrically Propelled from an Overhead Wire.
Year: 1899

page_text: Date of Application, 19th Oct., 1899
Complete Specification Left, 3rd July, 1900-Accepted, 25th Aug., 1900
PROVISIONAL SPECIFICATION.
Improvements in Trolley Standards used on Cars or Wagons
Electrically Propelled from an Overhead Wire.
We, EDWARD MAY MUNRO, Engineer, of Edinburgh Chambers, Baldwin Street,
WILLIAM WOOD, Engineer, of Victoria Buildings, St. George, HENRY BRECKNELL,
Engineer, and HUGH INNES ROGERS, Engineer, both of Edinburgh Chambers,
Baldwin Street, all in the City and County of Bristol, do hereby declare the
nature of this invention to be as follows; -
Our invention relates to an improved means of attaching a spring or springs
to the pole or arm mounted on the standard and carrying the trolley in connec-
tion with the overhead wire, so that the effort of the spring shall when com-
municated to this arm, cause it to press against the overhead wire with a uniform
pressure at whatever position or height the arm may be constrained to run at.
Hitherto these trolley arms have exerted a greater or lesser pressure upon the
trolley wire according to the angle at which the trolley pole is constrained to
run in relation to the standard.
In our invention we obviate this objectionable feature and procure a uniform
pressure as follows-
The spring or springs are suitably arranged to exert a pressure upon a lever
which carries the trolley pole and is so fulcrumed upon the trolley standard that
when the trolley pole is in its position of extreme height the spring is then
exerting its weakest effort at the greatest length of leverage.
Upon the pole being depressed the lever travels round and approaches a line
which is approximately parallel with the direction of the force of spring so
that as the pressure of the spring upon the lever is increased by reason of the
dropping of the pole or arm so the effective leverage connecting it with the pole
is shortened in such a ratio as to neutralize the excessive pressure of the spring
and preserve the uniform pressure at the end of the pole upon the wire.
It would be possible by continuing to pull the pole down to bring the longi-
tudinal centre line of lever practically in a line parallel and coincident with
the direction of the effort of the spring, when, and in such case the whole effort
of the spring would be taken by the fulcrum and would simply set up a re-
action on the fulcrum without transmitting any effort to the lever, but our lever
only approaches so near that parallel line as to shorten its effective leverage,
so that the effort of the spring is resolved into two forces, one is absorbed by the
re-action of the fulcrum pin and the other goes to pull the trolley pole end
up to the wire at the uniform pressure desired, the ratio of these forces being
governed by the varying angle between the line of direction of effort or pressure
from spring and the centre line through the eye of lever and fulcrum.
Dated this 18th day of October, One thousand eight hundred and ninety-nine.

page_text: Improvements in Trolley Standards used on Cars or Wagons
Electrically Propelled from an Overhead Wire.
We, EDWARD MAY MUNRO, Engineer, of Edinburgh Chambers, Baldwin Street,
WILLIAM WOOD, Engineer, of Victoria Buildings, St. George, HENRY BRECKNELL,
Engineer, and HUGH INNES ROGERS, Engineer, both of Edinburgh Chambers,
Baldwin Street, all in the City and County of Bristol, 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 trolley standards for carrying the trolley arms of cars
and wagons which are propelled by electric motors, the current for actuating
which is supplied through an overhead wire. As is well understood, the trolley
wheel has to be kept in contact with such overhead wire. This contact is, as
is also well understood, maintained by the action of a spring or springs acting
upon the trolley arm and keeping the trolley wheel up against the wire.
As generally arranged, the trolley arm, on being depressed, exerts on the
spring or springs a compressing force which increases as the arm is lowered.
Consequently, the trolley arm, the spring or springs, the trolley wheel and the
overhead wire are subjected to severe and widely varying strains.
This invention, which has for its objects to ease the said strains, consists in
means for effecting this purpose.
According to this invention the trolley arm is secured to a lever which is
pivotted to the head of the standard, which head is free to turn on a ball-
bearing provided in the mast of the standard. One end of a rod contained within
the standard is attached to the said lever. The other end of the said rod is
connected to the plunger or disc, between which and a ring fitted in an internal
tube concentrically arranged in the mast of the standard is situated the spring.
The spring column may either be continuous, or it may consist of separate springs
constituting a divided spring column. The head of the standard is screwed
to the said internal tube. The cable is conducted up from the car or wagon into
the internal tube of the mast and is thence led up through the head and into
the trolley arm. The lever pivotted to the head of the standard is so disposed
that the minimum force allowed to the spring is exercised when the arm is
raised to the maximum limit of elevation, that is to say, at the greatest extent of
leverage. In the depression of the trolley arm caused by the position of the
overhead wire, the lever turns outward on its pivot with the result that as the
pull exerted on the lever by the spring increases in power as the trolley arm
is lowered, so the effective leverage as between the line of strain and the lever
carrying the trolley arm is shortened in such a ratio as to operate in counteraction
of the pull exerted by the spring. In this way the upward pressure exerted on
the wire by the trolley arm is kept within comparatively easy working limits.
Referring to the accompanying drawings, Fig. 1 represents, in vertical section,
a trolley standard constructed and arranged in accordance with our invention.
Fig. 2 is a transverse section on the line, Fig. 1. Fig. 3 is a plan of the
upper part of the standard, the cap at top being shown as turned back on its
hinge. Fig. 4 is an elevation of the upper part of the standard as seen from
that side at which the trolley arm is situated. Fig. 5 is a vertical section, drawn
to an enlarged scale, of that part of the standard which is about the ball
bearing on which the head of the standard turns. Fig. 6 is a transverse section
of Fig. 5.
To the base shoe a, which, as is usual, is secured to the roof or deck" of

page_text: the car, is fixed, by the rivets b, a tubular mast c, within which is a tube d
on which is screwed a head e which is capable of turning about its own axis on
the ball bearing f, thus allowing the trolley arm to be turned about, as is well
understood to be requisite. The mast e, tube & and head e may be referred to
collectively as the standard. Within the standard is a rod y which is, at the
lower end, pivotally connected to the plunger h. At the other end, the rod g
is pivotally connected by the pin g to the lever which is fulcrummed on the
pivot pin fixed in the head e. The lever is, at its outer side, divided or split
and recessed. The trolley arm j fits into the recess and is firmly secured in
place by the pinching bolt bridging the "split in the lever, as seen more
particularly at Fig. 4.
A stop pin f¹ is screwed into the collar 2 of the ball bearing and projects
outwardly in the groove el provided in the head e, which latter has a projection e²,
as shown at Fig. 6. The projection by coming into contact with the pin f¹
prevents the heade from turning through a complete revolution.
Secured in the tube is a ring between the underside of which and the
upper face of the plunger is the spiral spring m which acts on the trolley arm j
through the rod g and lever i. The trolley cable is conducted from the car up
inside the coils of the spring m, and has a free run to the trolley arm and
trolley. The head e of the standard is surmounted by a cap o hinged at and
having a peak extending outwards partially over the lever i. The peak o
of the cap serves as a rain and dust guard to the interior of the standard.
The arrangement is such that when the trolley arm is raised to the full height
which it would, in ordinary practice, be required to reach, the spring m is exerting
its minimum effort at the greatest length of leverage. As the car travels, the
arm moves the lever i about its pivot according to the varying height at which
the overhead wire is carried. As the trolley arm becomes depressed in obedience
to lowered positions of the overhead wire, the effective leverage as between the
lever and the rod y is shortened in such a ratio as to counteract the increased
effort of the spring m. In this manner the upwardly-exerted force acting on the
arm is kept within such comparatively easy limits as to materially reduce
strain and tear and wear of the parts affected..
By lowering the trolley arm to a sufficient extent the line from the centre
of the pivot pin to the centre of the pin g may be brought to be almost
parallel and coincident with the centre line of the rod g. In such a case the
whole effort of the spring m, except such part as is absorbed by friction, would
be borne by the fulcrum pin of the lever i, on which fulcrum a re-action would
be set up without transmission of effort to the lever . But the lever, in
ordinary working, approaches only so near the aforesaid position as to shorten
its effective leverage so that the effort of the spring m is resolved into two
forces, of which one is absorbed by the re-action of the fulcrum pin and the
other acts upon the trolley arm keeping it up to the overhead wire with a
comparatively easy strain. The ratio of the said forces is governed by the vary-
ing angle between the line of direction of effort exerted by the spring m, that
is to say, the centre line of the rod g, and the line through the centre of the
pivot pin and the pivot pin g¹.
The stop screw d which is screwed into the tube a through an aperture pro-
vided therefor in the shoe « prevents the tube d being accidentally lifted out.
The stop screw is readily removable.
The spring m, plunger h and rod g and also the internal tube d can be taken
out of the mast without removing the latter. This facilitates repairs and
replacement.
When the arm jis lowered so that the trolley wheel is pulled down off the
wire by means of the cord usually attached to it, the arm ; will remain at rest
in the position to which it is so pulled. This affords convenience in and facili-
tates repairs.

page_text: Having now particularly described and ascertained the nature of this
invention, and in what manner the same is to be performed, we declare that what
we claim is;-
1. In trolley standards and trolley arms for tramcars, wagons and like vehicles
electrically propelled from overhead wires, means for easing the strains on the
trolley arms, the spring or springs, and the wires and other parts; the said
means consisting of a compensating lever having the trolley arm secured to it
and which lever is pivotted to the standard and connected to a rod which is
acted upon by the spring or springs, the arrangement being such that as the
pull exerted on the lever by the spring or springs increases in power as the
trolley arm is lowered, so the effective leverage as between the line of strain
and the lever carrying the trolley arm is shortened in such a ratio as to operate
in counteraction of the pull exerted by the spring or springs, substantially as
hereinbefore set forth.
2. In trolley standards and trolley arms for electrically propelled tram-cars,
wagons and like vehicles, means for attachment and for operation of the trolley
arm; the said means consisting of a compensating lever such as i pivotted on
the standard head as at 1, and a connecting rod such as g pivotally connected
at one end, as at g', to the said compensating lever and pivotally connected at
the other end to a plunger such as arranged to act on the spring or sprin
through the agency of which the trolley arm is held up to keep the trolley
wheel in contact with the overhead wire, the parts being constructed and arranged
substantially as hereinabove described and shown in the accompanyng drawings,
and operating in the manner above set forth and for the purposes specified.
Dated this 26th day of June 1900.
NICHOLAS WATTS,
Chartered Patent Agent, Bristol.