Improvements in Apparatus for Starting Tramcars and similar. Conveyances.
Year: 1887

page_text: Date of Application, 30th Sept., 1887
Complete Specification Left, 30th June, 1888
Complete Specification Accepted, 3rd Aug., 1888
Improvements in Apparatus for Starting Tramcars and similar.
Conveyances.
I EDGAR DREDGE of 268 Mare Street, Hackney in the County of Middlesex,
Engineer do hereby declare the nature of this invention to be as follows:
:~
The object of this invention is to provide apparatus for starting tramcars and similar
conveyances, by which the power stored up during the stopping of the tramear, and
derived from the compression of a spring, or in other ways, will be more fully
utilized than heretofore.
Numerous attempts have been made to provide an efficient apparatus for the
purpose mentioned, but hitherto without practical results, the reason, according to my
view, being that the stored power, instead of being exerted direct on the car axles, is
communicated thereto through a complicated system of gearing, the driving of which
uses up, so to speak, the stored power before it can get to the axle..
In carrying out my invention, I dispense with all complicated systems of gearing,
and I communicate the stored power direct to the axle, through a rack and a silent,
clutch mounted on the axle.
The power may be derived from a spring of any suitable kind, or from compressed
air or gases or vacuum, or in any other suitable or convenient manner, the spring, or
the air or vacuum cylinders, being secured to the underside of the car, and outside or
in front of the axles.
The spring or piston rod is connected to one end of a rack, the other end of this
rack being attached to a chain which passes over a suitably placed guide pulley, and
is sured to a friction drum mounted loosely on the car axle. This drum is driven by
a friction-clutch mounted on the axle, and which is thrown into gear with the drum
in any convenient manner by the driver.
When this clutch is in gear, the chain will be wound up on the drum, the rack will
be drawn out, and tension will be applied to the spring, or the air will be com-
pressed, or the vacuum produced, as the case may be.

page_text: The silent clutch, which is formed with teeth on its outer periphery, will allow of
the rack being drawn out, but the least backward motion of the rack under the
influence of the stored power, will immediately throw the clutch into gear, and its
movement will be communicated to the axle.
As from the position of the clutch it may be made of comparatively large diameter,
a considerable amount of leverage will be obtained to start the car.
The apparatus above described is simple, and though there will be one to each axle,
they will add but comparatively little to the weight of the car.
The silent clutch which I prefer to use consists of a pulley keyed onto the axle, and
working in a casing mounted loosely on the axles. This case has on its outer periphery
spur teeth, and on its inner periphery a series of excentric faces, between which and
the outer periphery of the pulley are placed a series of wedges and rollers, which,
under certain conditions, jam the two parts together, but any other clutch of similar
´character will also answer the purpose.
The act of storing the power will of course serve, to a greater or less extent, to stop
the car.
Dated this 30th day of September 1887

page_text: Improvements in Apparatus for Starting Tramcars and similar
Conveyances.
I EDGAR DREDGE of 268 Mare Street, Hackney in the County of Middlesex,
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 object of this invention is to provide apparatus for starting tramcars and
similar conveyances, by which the power stored up during the stopping of the
tramcar, and derived from the compression of a spring, or in other ways, will be more
fully utilised than heretofore.
Numerous attempts, have been made to provide an efficient apparatus for the
purpose mentioned, but hitherto without practical results, the reason, according to
my view, being that the stored power, instead of being exerted direct on the
car axles, is communicated thereto through a complicated system of gearing, the
driving of which uses up, so to speak, the stored power before it can get to
the axle.
In carrying out my invention, I dispense with all complicated systems of gearing,
and communicate the stored power direct to the axle through an open link chain
and a friction clutch of any suitable or convenient construction mounted on
the axle.
The power may be derived from a spring, or from compressed air or gases or
vacuum, or in any other suitable or convenient manner, the spring, or the air or
vacuum cylinder or cylinders being secured to the underside of the car, outside or in
front of the axle.
The spring or the piston rod is connected to one end of the open link chain, the
other end of this chain being attached to a chain which passes over a suitably placed
guide pulley, and is secured to a drum forming part of a clutch mounted loosely on
the car axle. This drum is thrown into gear with the fixed part of the clutch on the
axle in any convenient manner by the driver.
The friction clutch, which is formed with teeth on its outer periphery, will allow of
the open link chain being drawn out, but the least backward motion of the said chain,
under the influence of the stored power, will immediately throw the clutch into gear,
and its movement will be communicated to the axle.
In the accompanying drawing,
Fig. 1 is a longitudinal section of so much of a tramcar as is necessary to illustrate
my invention.
Fig. 2 is an underside plan view, and
Fig. 3 is a front view of the friction clutch which I prefer to use, with the front
plate or cover removed.
In the drawing, I have shown a spring as the means for storing the power, but this
is only as an example; any other means may be readily applied for my purpose.
The invention will be applied to both axles, though for simplicity in the drawing,
I have shown it as applied to only one.
A is the frame of the car, B the wheels, and C the wheel axles.
D is a friction clutch mounted on the axle.-E is a clutch of any convenient

page_text: construction, also on the axle, and arranged to be operated by the lever handle E¹ in a
manner well understood. The loose portion of this clutch E is provided with a drum
or pulley E3, on which a chain F is wound, when this part of the clutch is thrown
into gear with the part which is keyed on the axle. The chain F, after passing
round a guide pulley, is secured to a cross head F¹, to which is attached, by the
chains F, one end of the open link chain G.-The other end of this chain is connected
to the means for storing up power, say a spring H.
The clutch D consists of a flanged disc D, forming a box which is mounted loosely
on the axle C, and provided internally of the flange with inclined or excentric faces.
D is a disc or pulley of about two-thirds the diameter of the box D keyed on the
axle, and arranged to work inside the box. Around the periphery of the disc D',
are arranged loose wedge pieces D2, and between the wedge pieces and the inclined-
faces of the box, are arranged series of balls or rollers. The disc D' will thus be free
to turn in one direction irrespective of the box D. The box D is provided externally
with teeth, which take into the open link chain G.
The action of the apparatus will be as follows:-
Suppose the car is proceeding in the direction of the arrow, Fig: 1, and it is
desired to stop. The clutch E will be thrown into gear, which will cause the chain F
to be wound up on its drum. This will distend the spring H, and cause the chain G
to engage with the teeth of the friction clutch D, and turn the box D in the reverse
direction, as shown by the dotted arrows, Fig. 3, which it will be free to do, being
loose on the axle.
The tension of the spring will act more or less as a brake to stop the car, and the
car will remain stationary so long as the clutch E is in gear.
When it is desired to start the car, the clutch E is released, and the spring is
then free to exert its power, which it will do by contracting and pulling on the
chain G. The chain & being in gear with the box D, will rotate the box in the
forward direction, and this will cause the wedge picces to jam against the periphery
of the disc D¹.
Rotary motion will thus be communicated to the disc D¹, and through it to the
car axle, by which means the car will be started.
As, by my arrangement, a clutch of comparatively large diameter may be used, 1
obtain a considerable amount of leverage, and therefore the action being powerful,
1 can employ a comparatively light apparatus, an advantage which will be fully
understood and appreciated.
It will thus be seen that in my improved arrangement of apparatus, the power is
transmitted direct to the axle without the intervention of a complicated system of
gearing, whereby much of the power is lost through the friction of the parts to be
driven before the power is communicated to the axle.
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. In car-starting apparatus, the application of a friction clutch D as and for the
purpose herein set forth.
2. In car-starting apparatus, the combination with a link chaiu, G, and means_for
drawing out the same against the pressure of a spring, or other agency for storing
power, of a friction clutch D mounted on the wheel axle, substantially as set forth.
3. The arrangement of car-starting apparatus herein described and shown in the
drawing.
Dated this 20th day of June 1888