Improvements in Speed Limit for Engines.
Year: 1896

page_text: Date of Application, 24th Nov., 1896-Accepted, 6th Feb., 1897
COMPLETE SPECIFICATION.
Improvements in Speed Limit for Engines.
1, FRANK PRATT REYNOLDS, of Number 9 Sigourney Street, Hartford, in the
County of Hartford and State of Connecticut, U.S A., Draughtsman, 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 those devices which are used in connection with engine
stops that are arranged to cut off the supply of operating fluid when an accident
happens, as the blowing out of a cylinder head, or a change of load occurs which
causes the engine to race or stop.
The object of the invention is to provide a simple, inexpensive and readily
adjustable device of this class which will he exceedingly sensitive and will surely
act at the necessary moment to set in operation the stop mechanism which is to
cut off or throttle the energizing fluid when the engine or shaft to which the limit
is connected races or stops, whether it be from variation of load or accident.
The invention resides in a device having a frame bearing a very freely running
spindle adapted to be connected with and rotated by the shaft or other part, the
speed of which is to be limited, with a disk of electrical conducting material
supported by the spindle and movable longitudinally thereon as the rates of speed
of rotation of the spindle vary, and terminals of an electrical circuit that embraces the
engine stop mechanism, so held by the frame that the disk will make good and sure
connection between them when the speed of rotation of the spindle is too rapid
and will also make connection between them when the speed of rotation is too slow,
and thus close the electrical circuit which sets the stop in operation, both when the
rotation is too rapid and when it is too slow, but not close the circuit when the
device is idle.
Referring
the invention :
to the accompanying drawings which illustrate a device embodying
Fig. 1 is a transverse section taken on plane denoted by the broken line X X,
looking downward,
Fig. 2 is an elevation of the device with parts broken away to show the
construction and position of the mechanisms when idle, and
Fig. 3 is a detail enlarged elevation of one of the circuit terminal blocks.
In the views 1 indicates the frame or bed of the device, which is usually enclosed
in any ordinary form of case 2. The frame may be formed of iron, or any other
suitable metal and the case may be wood.
The spindle 3 is supported so that it may have a free rotation in bearings in.
arms extending from the frame. The bearings are preferably formed by inserting
steel cups 4 in recesses formed in the arms about the spindle perforations and
locating anti-friction balls in the cups, then securing collars upon the spindle
outside of the balls. One collar 5 is preferably pinned to the spindle while the
other collar 6 is held by means of an adjusting nut 7 and a clamping nut 8 to allow
ready adjustment and ensure a very easy rotation of the spindle.
The spindle outside of the case bears a pulley 9 that is adapted to be belted or
otherwise connected with the journal of an engine or other shaft, the rate of

page_text: rotation of which is to be limited by this device. The pulley preferably has a
flange 10 on the inside and attached to the case about the spindle perforation is an
annular plate with a flange 11 that projects behind the flange on the pulley to
guard against the entrance into the case of dust, dirt and oil.
Upon the spindle is a fixed hub 12 and a movable hub 13, a collar 14 being provided
to determine the limit of movement of the hub 13 along the spindle. These hubs
are connected by ordinary sensitive leaf springs 15 which bear weights 16.
These weights fly outward under centrifugal force when the device is running
according to the speed of rotation of the spindle and draw the hub 13 toward the
hub 12. Secured to the hub 13 is a disk 17 of copper or any other suitable
conductor of electricity, and the edges of the disk project outward a little distance
beyond the peripheral walls of the hub.
Held in an opening in one arm of the frame is a block 18 and loosely supported
in perforations through this block are rods 19. The rods 19 are made of conducting
material and, as it is necessary to insulate them from each other, the block 18 may
be made entirely of non-conducting material or insulating bushings may be placed
in the perforations through which the rods extend. The lower ends of the two
rods are connected with the wires of an electrical circuit that includes the engine
stopping mechanism which, for instance, may be of the class that when excited
throttles the supply of energizing fluid to the engine. The upper ends of these
rods have enlarged heads 20.
Supported by each of the heads 20 is a spring finger 21. These fingers are shaped
and located so as to extend forward and make contact with the revolving conducting
disk that moves with the hub 13 on the spindle when the disk has reached one of
the limits of its movement. That is, these fingers are arranged to be engaged by
the disk when the disk is in the position it will be drawn to by the movable hub
and centrifugal weights at the time the rotation of the spindle reaches the desired
maximum limit of speed. The engagement of the fingers that are connected with
the wires, by the conducting disk completes the circuit through the fingers and this
excites the stop and brings its mechanism iuto play for throttling or cutting off
the fluid that is driving the engine.
Each of the heads 20 preferably also bears a conducting contact 22. These
contacts are formed by bending pieces of spring metal into form and adjustably
securing them to the edges of the heads. These contacts are shaped and located so
that they will be engaged by the disk attached to the movable hub 13 when that disk
is in a certain position. The fingers 21 are located so as to be engaged by the disk
when in the position it will occupy at the time the rate of rotation of the spindle
bas reached the desired maximum, and the contacts 22 are located so as to be
engaged by the disk when in the position it will occupy at the time the rate of
rotation of the spindle falls below a desired limit. Thus, if the rate of rotation
exceeds a desired limit the disk closes the circuit through the fingers 21, and if the
rate of rotation falls lower than a desired limit the disk closes the circuit through
the contacts 22, which in either case, as above stated, excites and causes the stop
to act.
The movable hub and the conducting disk will preferably, when the spindle is
rotated at normal speed, occupy the position shown in dotted outlines in Fig. 2,
with the edge of the disk revolving between the fingers and contacts so that an
increase of speed will draw the edge of the disk into contact with the fingers 21
and a decrease of speed will draw the disk into contact with the contacts 22.
Each contact 22 is preferably held by a bolt 23 to permit of its adjustment on
the edge of the head, the bolt passing through a slot in the contact piece, so that
the distance between the fingers 21 and the contacts 22 may be regulated. The
contacts 22 are placed so that the engaging points are below the position that the
disk will occupy when the spindle is rotating at its normal speed so that the circuit
will be closed when the speed is reduced, but these contacts are placed above the
position that the disk will occupy when the spindle is at rest so that the circuit
will not remain closed when the engine is stopped. If the disk rested in a position

page_text: joining the contacts and closing the circuit through them when the engine was
stopped at noon or night, for instance, the operating battery would be unnecessarily
excited and soon exhausted. The disk in its movement springs the contacts so that
it can readily pass them, making the desired contact and then rest clear of the
contacts.
The rods 19 are attached to a disk 24 that is connected with an adjusting
screw 25. The screw 25 preferably passes through a perforation in the disk 24
which is held so as to move longitudinally but not to rotate with the screw, by a
collar 26 and a handle nut 27. The screw is preferably held by a threaded socket
tapped in the block 18 so that by turning the screw in or out the rods 19 with the
heads 20 supporting the fingers 21 and contacts 22 may be adjusted to the proper
position to be connected by the disk at the exact time the speed limits are
reached.
The limits of the movement of the conducting disk connected with the movable
bub are ascertained and the conducting fingers and contacts are located and
adjusted to be engaged by the disk at the proper time. The contacts 22 are set so
that the disk will have the proper play between the fingers and the disks, allowing
for all ordinary variation in the speed of the engine without causing it to be shut
down, and then all of the contacts are nicely regulated by means of the adjusting
screw, the turning of which moves all simultaneously. When these are adjusted
to the proper position and the circuit wires are connected with an engine stop, if
the engine or shaft to which the spindle of this limit is connected runs more rapidly
than it should and the governor fails to act, the centrifugal action of the weights
draws the movable hub and disk so that the fingers 21 are caused to bear against
the surface of the disk and the circuit closed. On the other hand, if the engine
or shaft runs more slowly than it should, due to a breaking down of a part of the
engine, the resilient action of the springs moves the hub and disk so that the
contacts 22 are engaged by the disk and the circuit closed.
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 a speed limit, in combination, a frame, a rotary spindle held by the frame,
a disk of conducting material supported upon and adapted to be moved longitu-
dinally of the spindle and caused to occupy varying positions along the spindle
according to the speed of rotation of the spindle, and conducting pieces located in
the path of and adapted to be engaged by the disk when the spindle rotates more
rapidly thun desired, substantially as specified.
2. In a speed limit, in combination, a frame, a rotary spindle, anti-friction balls
inserted between the rotary spindle and bearings in the frame, a disk of conducting
material supported upon and adapted to be moved longitudinally of the spindle and
caused to occupy varying positions along the spindle according to the speed of
rotation of the spindle, and conducting pieces located in the path of and adapted
to be simultaneously engaged by the disk when the spindle rotates more rapidly
than desired, substantially as specified.
3. In a speed limit, in combination, a frame, a rotary spindle, a disk of
conducting material supported upon and adapted to be moved longitudinally of the
spindle and caused to occupy varying positions along the spindle according
to the speed of rotation of the spindle, and conducting pieces held by the frame in
such manner as to be adjustable longitudinally of the spindle and to project into the
path of and be simultaneously engaged by the disk when the spindle rotates more
rapidly than desired, substantially as specified.
4. In a speed limit, in combination, a rotary spindle bearing a fixed sleeve and a
movable sleeve, said sleeves being joiued by springs bearing weights, a disk of
conducting material connected with the movable sleeve, rods of conducting material
adapted to be connected with electric circuit wires, each of said rods bearing a
plural number of conducting contacts adapted to be engaged by the disk on the

page_text: sleeve when the disk is moved into certain predetermined positions, substantially as
specified.
Dated the 23rd day of October 1896.
FRANK PRATT REYNOLDS.
Boult & Wade,
Agents for the Applicant.