Improved Means applicable for Use in Working Change-speed. mechanism in Tram-cars, Motor-cars, and the like.
Year: 1897

page_text: Improved Means applicable for Use in Working Change-speed.
mechanism in Tram-cars, Motor-cars, and the like.
I, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the County
of Middlesex, Civil Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improved means, applicable for use in train-cars motor-
cars and the like, for operating change-speed-mechanism; particularly mechanism of
the type described in the Specification to my Letters Patent, dated 24th April, 1894,
No. 8,150. According to the construction therein described, each gear-train is
brought into operation by tightening a friction-strap about a drum; the friction-
strap being connected to a lever which is pivoted at one extremity, whilst its opposite
extremity is moved by means of a chain, wire-rope, rod or other suitable connection
brought within convenient reach of the driver.
In applying such mechanism to motor-cars or road-carriages where the carriage-
body is mounted on springs, and where there is in consequence considerable play
between the body and the frame carrying the propelling machinery, certain difficulties
are met with in the employment of rods, levers and similar mechanical connections,
for working the friction-strap-levers pertaining to the change-speed-mechanism.
My present invention is designed to avoid these difficulties, as also to enable a change
of speed to be effected without serious muscular effort on the part of the driver.
In working change-speed-mechanism according to my improved method, I employ
a small air-compressing pump, which may be worked by the motor engine and which
delivers air to a small storage reservoir. A flexible pipe leads herefrom to a
controlling valve-apparatus or device mounted in the car-body within easy reach of
the driver; and from the controlling device, pipes lead to air-cylinders mounted upon
the frame. Each cylinder is provided with a piston, which is connected to one of the
friction-strap-levers. The controlling device is constructed in such a manner that,
upon placing the driver's handle in one of several indicated positions, compressed air,
is admitted to one of the cylinders, with the effect that its piston and connected
lever are actuated and the friction-strap pertaining to the corresponding speed-gear
tightened, so as to render that particular gear operative. So long as the
driver's handle remains in that position, the compressed air continues to act on
the piston and to maintain the strain upon the lever and friction-strap; but, upon the
driver's handle being moved to another position, the compressed air escapes from
the cylinder, the lever and friction-strap are released, and the corresponding speed-
gear is thrown out of operation.
According to an alternative method of working, I employ electrical instead of
pneumatic means for working the several friction-strap-levers.
The
Each lever is provided with a solenoid, whereof the coil is attached to the frame,
whilst the core is mounted upon or is connected with the lever, or vice versa.
controlling mechanism in the car or carriage comprises a driver's handle, in
electrical connection with a source of electrical energy, and a series of contact plates,
T077

page_text: each in electrical connection with one of the solenoid coils; so that, upon the driver's
handle being placed in one of several indicated positions, electrical connection is
established with the particular solenoid, friction-strap-lever and speed-gear, to be
brought into operation.
Improved Means applicable for Use in Working Change-speed-
mechanism in Tram-cars, Motor-cars, and the like.
I, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the County of
Middlesex, Civil 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 :-
This invention relates to improved means, applicable for use in train-cars, motor-
cars and the like, for operating change-speed-mechanism; particularly mechanism of
the type described in the Specification to my Letters Patent, dated 24th April, 1894,
No. 8,150. According to the construction therein described, each gear-train is
brought into operation by tightening a friction-strap about a drum; the friction-strap
being connected to a lever which is pivoted at one extremity, whilst its opposite
extremity is moved by means of a chain, wire-rope, rod or other suitable connection,
brought within convenient reach of the driver.
In applying such mechanism to motor-cars or road-carriages, where the carriage-
body is mounted on springs, and where there is in consequence considerable play
between the body and the frame carrying the propelling machinery, certain difficulties
are met with in the employment of rods, levers and similar mechanical connections,
for working the friction-strap-levers pertaining to the change-speed-mechanism. My
present invention is designed to overcome these difficulties, as also to enable a change
of speed to be effected without serious muscular effort on the part of the driver; the
friction-strap-levers being actuated either by pneumatic or by electric means.
In the following description, the application of the invention to a road-carriage in
which the pneumatic method of operating the friction-strap-levers is employed is
adopted by way of illustration.
Referring to Figs. 1 and 2 of the accompanying drawings, which represent
respectively a longitudinal section and an under side view of a car-body fitted with
change-speed-mechanism of the character herein before referred to, A is a small air-
compressing pump delivering air to a storage reservoir B, provided with a relief valve
(not shown). M M are motor-cylinders whereof the pistons are connected with crank-
discs N N keyed on the motor-shaft O, on which the change-speed-gear P is in the
present instance mounted. The spur-wheel P¹ of the speed-gear ineshes with the
spur-wheel P2 of the balance-gear P3 pertaining to the driving axle S. Motion is
transmitted from the main shaft 0 through a pitch pinion 01, chain 02 and
pitch wheel (3 to a counter-shaft T, the latter being furnished with an eccentric T
which serves to work the air-compressing pump A. A flexible pipe C leads from the
reservoir B to a controlling device D, or "driver's valve," mounted in the car-body
within convenient reach of the driver. From the driver's valve, pipes H, L, R lead to
air-cylinders H¹, L, R mounted on transverse bars F upon the car-frame. Each
cylinder is provided with a piston which may be connected to one of the
friction-strap-levers H2, L2, R2 pertaining to the high-speed, low-speed and reverse
speed-gears. Or the pistons may be fixed whilst the cylinders are connected to the
levers and rendered moveable as shown in the arrangement adopted for the purpose

page_text: of illustration. The driver's valve is construted as hereinafter more particularly
described with reference to Figs. 3 to 7 and is arranged in such a manner that, upon
placing the handle in one of several indicated positions, compressed-air is admitted to
one of the cylinders H³, L' or R¹, with the effect that the cylinder is operated and the
lever H2, Lor R² connected therewith is actuated to tighten the friction-strap of the
So long
corresponding speed-gear and thus to render that particular gear operative.
as the driver's handle remains in that position, the compressed-air continues to act on
the piston and to maintain the strain upon the lever and friction-strap; but, upon the
driver's handle being moved to another position, the compressed-air escapes from the
cylinder, the lever and friction-strap are released, and the corresponding speed-gear is
thrown out of action. In Fig. 1, the free ends of the bi-part friction-strap-lever
engage with trunnions tt which project laterally from the cylinder L (H' or R¹); one'
end of the connecting rod being pivoted in the piston or trunk, while the other end
of the rod is pivoted to the bar F.
One mode of constructing the driver's valve is illustrated in Figs. 3 to 7; Fig. 3
being a face view, Fig. 4 a vertical section, Fig. 4 a fractional view in section on a
line taken through the inlet from the compressed-air reservoir, Figs. 5 and 6 sections.
on the line x-x in Fig. 4, the former looking to the left and the latter looking to the
The apparatus comprises a
right, and Fig. 7 a section on the line 7-7 in Fig. 4.
bi-part casing formed of two plates a and b, fastened together by bolts a*; a rotary
valve d, fixed on a spindle f, working in a recess formed in the inner side of each
plate. The outer end of the spindle is furnished with a handle or lever f¹ which works
over a quadrantal plate f². The handle is provided with a spring catch f³ which
engages in depressions h, l, e and e¹ arranged at suitable positions in the face of the
plate f; the several positions being appropriately marked to indicate to the driver
the respective effects obtainable; the stops f f limiting the extreme movement of
the hand-lever. Each of the plates, a, b, is formed with ribs or partitions which form
compartments or passages a¹, a², a³, a and b¹, 62, 63, 64 respectively. From these
compartments open ports a³, a, a, as and 65, 66, 67, 68. The rotary valve d is pro-
vided with annular spaces d¹ d²; ports d¹º and d¹x opening into the space d', while
ports do d2x2xx open into the space d².
In the drawings, the apparatus is shown in the neutral or exhaust position,
the handle or lever f¹ being midway between the position for rendering operative the
On moving the
low speed-gear and that for rendering operative the reverse gear.
lever to the position immediately over the depression in the quadrantal plate f²,
compressed-air is admitted through the pipe L pertaining to the cylinder L' for
actuating the friction-strap-lever of the low speed-gear; the pressure fluid reaching
the pipe L by way of the passage c in the plate b, passing thence through the
compartment at and ports as and d¹× into the annular space d', issuing therefrom by
way of the ports d'° and a into the compartment or passage a² and thence by way of
the pipe L to the cylinder L'. The pressure fluid being admitted above the piston
causes the cylinder to rise and to operate the corresponding friction-strap-lever,
thereby tightening the friction-strap about the drum pertaining to the low-speed
gear, which is thus brought into operation.
In changing from one speed-gear to another, it is necessary to release the
one before applying the other. This is accomplished in the following manner :-
Assuming the change is to be from the low speed to the high speed, the lever f', in
being moved towards the position indicating the high speed, causes the valve in the
first place to cut off the air supply to the cylinder of the low speed-gear, and then,
arriving at the position e¹, to open the exhaust E, whereby the air is allowed to escape
from the cylinder L¹ and the low speed-gear is released. On continuing the move-
ment of the hand-lever f¹ until the position h on the plate f2 is arrived at, com-
munication is established between the compressed-air reservoir B and the cylinder H¹;
the pressure fluid passing through the ports as, dix, do and as into the compartment
or passage a¹, and thence by way of the pipe H, to the cylinder H¹, raising such
When it is desired to stop
cylinder and rendering the high speed-gear operative.
the car, the hand-lever is brought to the nearest position of " exhaust," the particular

page_text: speed-gear in use at the time being thereupon released. The reverse gear is brought
into operation and released in precisely the same manner as the high and low speed-
gears. It will be observed that, in changing from one speed to another, the land-
lever must necessarily pass an "exhaust" position. Also that only the air contained
in the cylinder is released; the communication with the storage reservoir being cut
off until the hand-lever arrives in one or the other of the "speed" positions or in
the "reverse" position.
In Fig. 4, the outlet for the exhaust is shown dotted for the purpose of illustrating
the connection of the exhaust pipe E with the compartment or passage; the com-
munication with the inlet compartment at of said passage being interrupted by the
wall of the fore-part of the casing a.
The alternative method herein before referred to, wherein electrical instead of
pneumatic means are employed for working the several friction-strap-levers, is more
appropriate for electrically-propelled cars or carriages; the driver's valve being
replaced by a switch, and a solenoid being substituted for each air-cylinder. The
solenoid coils are mounted upon the frame and their cores attached to the friction-
strap-lever, or vice versú. The controlling mechanism in the car or carriage com-
prises a driver's handle, in electrical connection with a source of electrical energy, and
a series of contact plates, each in electrical connection with one of the solenoid coils;
so that, upon the driver's handle being placed in one of several indicated positions,
electrical connection is established with the particular solenoid, friction-strap-lever
and speed-gear to be brought into operation.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I claim :—
1. The improved means applicable for use in working change-speed-mechanism in
tram-cars, motor-cars and the like, arranged or operating substantially as herein
described, and whereby the employment of mechanical connections, between the car-
or carriage-body and the frame, for working the change-speed-mechanism is avoided.
2. The improved method of working change-speed-mechanism, substantially as
herein described, and consisting in the employment of a pneumatic cylinder, applied
to each speed-gear-friction-strap-lever; the air supplied thereto and release therefrom
being controlled from the driver's seat by means of suitable valve mechanism.
3. The improved controlling-valve-mechanism, constructed substantially as
described with reference to Figs. 3 to 7 of the accompanying drawings, and adapted
for rendering operative or inoperative either or any of two or more speed-gears.
Dated this 1st day of December 1897.
G. G. M. HARDINGHAM.