Improvements in Mechanism for Controlling the Application of Power.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in Mechanism for Controlling the Application of
Power.
A communication by JAMES FRANCIS MCLAUGHLIN, of 1742, Diamond Street,
Philadelphia, in the State of Pennsylvania, United States of America,
Electrician.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster and 323, High Holborn, 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:-
In
This invention has reference to improvements in power controlling mechanism
designed to be actuated by an operator for applying power to machinery driven
by any available agency such as electricity, steam, compressed air, water, or by
the direct communication of mechanical agency, as by clutches, grips &c.
mechanism of this sort heretofore used, when it was desired that the power be
applied in a gradual manner, either to prevent shocks to the machinery or to secure
other advantages, the operator was instructed to actuate the controlling mechanism
with a certain moderate speed in the direction for applying the power, and rapidly,
in the direction for cutting off the power; but there was nothing in the meclianism
under his control to prevent him disobeying or neglecting the instructions received,
and by reason of such disobedience, forgetfulness or neglect, injury was frequently
done to costly and delicate machinery.
Thus for instance, in electric motor cars where ordinarily a segmental rack and
lever are employed for applying the current, and for clutching a freely rotating
armature to the gearing by which motion is communicated to the driving axle, it
is of importance to turn on the current gradually, and also to apply the clutch in
a gradual manner, since otherwise, the armature may be burned out and the car
frame may receive dangerous jars.
In other electrical operations, as for instance, in electric welding, it is desirable
to turn on the current very gradually, since otherwise, the contacting surfaces of
the metals to be welded may be burned.
In the operation of steam, water, or air motors, it is also desirable that the
throttle-valves be opened slowly, and in the ordinary cable cars it is imperative
that the grip should be applied in a gradual manner, since the rapid application of
the grip would not be tolerated by the passengers patronizing the road.
Still, in all these modes of driving machinery and of propelling cars, there is
no provision made that will prevent the operator from applying the power as
suddenly as he desires, and thus the safety of expensive machinery, and the
comfort and safety of passengers are entrusted to the intelligence and good will of
an operator.
The object of this invention is to overcome these objectionable features in the
application of motive power, by forcibly and automatically controlling the operator
in the application of the motive power, in such a manner, that he can apply the
power only with a certain definite pre-determined, moderate speed, while he is
allowed to withdraw the power with any desired speed. This result is accomplished
by combining the operating lever or rod with a segmental or rectilinear ratchet
and an anchor or escapement pawl so related to the ratchet as to lock the lever or
rod in one direction against rapid movement, but leaving it free to move in that
direction with a certain definite moderate speed, while in the other direction the
operating lever or rod is free to move with any speed."

page_text: Since the escapement pawl and ratchet, constructed to effect this result, depend
for their action directly upon the speed of movement of the actuating lever or
rod and since the lever or rod is instantly locked, or its speed checked by the
action of the escapement pawl and ratchet, the said escapement pawl.and ratchet
constitutes an effective speed lock or speed check for the lever or rod.
This improvement is applicable for use in a great number of devices but it is
particularly useful for controlling the speed of application of motive power to
motor cars, and more especially to electric motor cars, all of which will more fully
appear from the following detailed description with reference to the accompanying
drawing in which :
Figure 1, is an elevation, representing the improvement by itself and without
regard to any specific application in the arts.
Figure 2 is a side elevation, partly in section, of a portion of an electric motor
car with the improvement applied thereto.
Figure 3, is a side elevation of a rheostat controlled by the improved mechanism
represented in two forms, both embodying the invention."
Figure 4, is a side elevation illustrating the application of the invention to the
control of throttle-valves.
Figure 5, illustrates an elevation of the invention as applied to cable cars,
showing the floor of the car in section, and
Figure 6, is a side elevation of a slightly modified form of ratchet which may be
used with the invention.
Like numerals of reference indicate like parts all throughout the drawing.
. Referring now to Figure 1, there is shown an operating lever 1, pivoted at a
point 2, to the base of a framework 3, the top bar 4, of which is a segment of a
circle described about the pivotal point 2, and the upper edge of which is formed
with ratchet teeth 5. The mechanism for applying power may be connected with
the lever 1, by rods, links, or otherwise, as will hereinafter appear or may be
connected to and actuated by the pivot 2, in which case the latter is keyed to the
lever 1, and loose in its bearings. This invention, however, is in no way limited
to any particular mode of and means for connecting the operating lever with the
mechanism actuated by the same for applying power, or for any other purpose,
and in Figure 1, which represents the invention in its generic aspect, therefore,
no connection of the operating lever has been illustrated.
It will be observed that the ratchet teeth 5, are formed with one side 6, radial
to the top bar 4, while the other side 7, forms an acute angle with such radius.
The ratchet teeth are spaced in a manner which will hereinafter more fully appear,
but preferably the bottoms 8, between two successive teeth are either straight or
curved upon the line cf circle described from the pivotal point 2, as a center.
To
To the lever 1, between the latter and a bracket 9, is loosely pivoted an anchor
or escapement pawl 10, in such position that the two teeth of the escapement pawl,
or one of them, may engage the ratchet teeth when the lever is rocked in one
direction or the other. The escapement pawl is not pivoted exactly in the middle
of its length, but at a point nearer to one end, so that the escapement pawl is in
effect a two-armed lever, one arm of which 11, is longer than the other arm 12,
so that when the escapement pawl is left free to the action of gravity, the longer
arm will preponderate and drop down causing its tooth 11', to engage the ratchet
teeth and lifting the tooth 121, of the short arm, to clear the ratchet teeth.
insure this result more clearly, the tooth 11, is made heavier than the tooth 12',
and in addition thereto a spring 13, fast on the lever 1, bears upon the long arm 11.
If the difference in length of the two arms of the escapement pawl is made con-
siderable, the tooth 111 on the long arm 11, need not necessarily be made heavier
than the tooth 12', or the spring 13, may be omitted. For the purpose of the
invention it is only necessary that one of the arms of the escapement pawl or
anchor have a tendency to descend so as to engage the ratchet and to lift the
other arm clear off the ratchet; it is therefore, not absolutely necessary that one
arm be longer than the other if it is sufficiently weighted, or, if not weighted, a

page_text: spring 13 is used, the invention is therefore not limited to any particular means for
giving to the escapement pawl a bias to descend with one of its arms, so long as
it is so biassed. In the position of the lever shown in Figure 1, with the escape-
ment pawl represented in solid lines, the tooth II', engages one of the ratchet
teeth against which it bears with one of its sides, while the edge of the tooth 11'
is at the bottom 8, of the space between two successive teeth; the other tooth 12',
of the escapement pawl is in this position lifted above the ratchet teeth, as is
clearly shown in the drawing. It will be understood that the escapement pawl
has come to this position either by the action of gravity upon the longer or
weighted arm 11, or by the action of the spring 13, or by the action of both and
it will be noticed that in this position of the lever and escapeinent pawl, the inner
side of the tooth 11', is inclined to the radial side of the ratchet tooth which it
engages; so that if the lever 1, is moved from this position in the direction of the
arrow, the inner side of the tooth 11', will be acted upon as a cain, so that this
tooth will be lifted out of engagement with the ratchet tooth; the outer side of
the tooth 11, is also inclined to the radial side of the ratchet tooth, although this
is not absolutely necessary as will appear further on.
The inner side of the tooth 121, of the escapement pawl, is also inclined to the
radial side of the ratchet tooth below it, for a purpose which will hereinafter appear,
while the outer side of the tooth 12', is practically in the line of a radius drawn
from the pivot 2, to said tooth.
The distance between the edges of the teeth 111, and 121, is slightly greater
than the aggregate distance between the upper edges of any desired number of
ratchet teeth. In the drawing (Figure 1) the edges of the escapement pawl teeth
are shown to embrace five teeth of the ratchet, that is to say, if the tooth 11', rests
with its edge upon a ratchet tooth, the tooth. 12' reaches beyond the fifth
succeeding tooth of the ratchet, counting the ratchet tooth upon which the
tooth 11, rests as the first; but the invention is not limited to any particular
length of the escapement pawl, as will be seen by reference to Figures 3 and 5,
which show, respectively, the escapement pawl embracing four and three ratchet
teeth; and it will be clear that it may embrace any number of ratchet teeth.
To the frame 3, there is secured a segmental bar 14, provided with notches 15,
which are engaged by a pin 16, actuated by a spring 17, and thumb-lever 18, (see
Fig. 2), in the usual manner, for locking the lever 1, in various positions to which
it may be moved. The operation of the invention will now be readily understood
from the following explanation in which reference will be made to various phases
of operation, illustrated in dotted lines, and marked by the letters a, b, c.
Assuming the position which the lever 1, occupies in the drawing to be that
which corresponds to that condition of the working mechanism in which the power
is "off" and that in order to turn the power on," it is necessary to move the
lever in the direction of the arrow to or near the other end of the ratchet, it
being understood that the more the lever is moved in that direction, the more
power is turned on, or the more forcibly a clutch or grip takes hold of the power
transmitting device. In the position of the lever shown in the drawing, the
weighted or biassed end of the escapement pawl is depressed either by gravity or
by the spring 13, or both, and the inner side of the tooch 11, bears upon the edge
of a ratchet tooth on its radial side 6, while the edge of the tooth 11', rests upon
the bottom 8, of the space between two successive teeth of the ratchet.
If now
the lever is moved in the direction of the arrow for turning on power, the
escapement pawl is tilted by the ratchet teeth acting upon the inner side of
tooth 11, until the escapement pawl assumes a position relative to the teeth of
the ratchet, such as is presented in dotted lines at a. This phase of operation is
characterized by the fact that the edge of the tooth 11', rests upon the edge of a
ratchet tooth, while the edge of the tooth 121, has entered between two adjacent
ratchet teeth and below the edges of the same. If now, the movement of the
lever is. continued slowly, the escapement pawl will assume a position illustrated
in dotted lines at 6b, and this phase of operation is characterized by the fact that-

page_text: the biassed end of the escapement pawl has slightly dropped, riding down the
inclined face of the ratchet tooth upon the edge of which it had rested a 'moment
-before, and thereby the tooth 121, has been raised above the edge of the ratchet
tooth immediately in front of it. A continued 'movement from this position will
allow the biassed arm of the escapement pawl to still further descend until it
again assumes the position with reference to the ratchet teeth, illustrated in solid
lines.
These operations will now be repeated over and over again, so long as the
lever 1, is moved slowly in the direction of the arrow, and there will be no impedi-
inent to such movement. If, however, from the phase of operation, represented
at a, the movement of the lever be accelerated, that is to say, if the operator should
attempt to move the lever rapidly, then the outer face of the tooth 12', will strike
the radial face of the ratchet tooth immediately in front of it, before the biassed
end of the escapement pawl has time to descend and thereby lift the tooth 12,
above the ratchet tooth. By such rapid movement therefore, the further progress
of the lever is arrested by the abutment of the outer face of the tooth 12, against
the radial face of a ratchet tooth, and this condition of affairs is represented in
dotted lines at (. When the lever is thus arrested, the escapement pawl is tilted as
shown with its tooth 111, raised above the ratchet teeth.
It will now be understood that the escapement pawl carried by the lever, together
with the ratchet, both constructed and co-operating as described, constitute an
effective speed lock or speed check for the lever, and that by the use of this
invention, an operator is positively prevented from applying power suddenly with
its full force, but is positively forced to apply that power gradually. By reference
to the phase of operation represented at a, it will be seen that the maximum speed
with which the power may be applied without obstruction, depends upon the distance
of the front face of the tooth 12', from the radial force of the ratchet tooth
immediately in front of it, when the edge of tooth 11', rests upon the edge of the
ratchet teeth; and that it also depends upon the depth to which the tooth 12,
reaches between two ratchet teeth when the edge of tooth 11', rests upon the edge
of a ratchet tooth; the greater that depth, and the smaller that distance, the
glower must be the movement of the lever in order to allow the biassed arm of the
escapement pawl to lift the shorter arm with its tooth 12' clear off the ratchet
tooth in front. Therefore, by making the space between the ratchet teeth long
and the depth to which the tooth 12¹ reaches small, the speed with which the lever
may be moved, becomes greater, while, when the space between the ratchet teeth
is made small, and the depth to which tooth 121, reaches is made comparatively
great, the maximum speed with which the lever may be moved in the direction of
the arrow is proportionately reduced. With this invention therefore, the speed
with which power may be applied can be predetermined with absolute certainty, and
it will be understood that while the operator controls the movement of the lever,
the lever in turn controls the action of the operator in a most positive manner.
When by a momentary rapid movement of the lever, the same is arrested in the
manner described, and illustrated at c, the operator can at once continue the slow
movement of the lever by first drawing that lever a very short distance backward
so as to allow the biassed arm of the escapement pawl to descend until it assumes
either of the positions represented at b, a, or in solid lines.
The backward movement of the lever for cutting off the power may be as rapid
as desired, since, during such movement, the edge of the tooth 11, rides up the
inclined faces of the ratchet teeth like an ordinary pawl, and if by very rapid
movement, the inclined face of tooth 12', should come in contact with the inclined
faces of the ratchet teeth, this can offer no impediment.
In Figure 6, is shown a modified form of ratchet teeth which may be used in the
invention. In this case, each tooth 5, has one radial face 6, as in the form shown
in Fig. 1, but the other face 7', instead of being an inclined plane, is curved
concavo, so that it merges into the bottom of the space between the successive
teeth. In this construction, the tooth 11', is allowed to descend more rapidly at

page_text: the beginning of its downward movement, so that the tooth 12', is more rapidly
made to clear the edge of the tooth immediately in front of it; the movement of
the lever therefore, for turning on the power may be a little more rapid than with
a ratchet of otherwise like proportions in which the inclined faces of the teeth are
plane. The form of the ratchet teeth may be variously changed in accordance
with the principle of the invention.
Referring now to Figure 2, the invention is there shown as applied to an electric
motor car.
In this instance, by the movement of the lever 1, in the direction indicated by
the arrow, the current from the secondary battery 19, is first turned on to the
electric motor, by passing it through one of the coil sections only of the field
magnet 20; by a continued movement of the lever, the current is allowed to pass
through additional coils of the field magnet whereby the power of the motor is
increased, and by a still further movement of the lever in the direction of the
arrow, the armature of the motor is by means of the clutch 20', clutched to the
gearing connecting with the driving axle, there being for this purpose a link 20",
which connects the lever 1, with the clutch 201. By this invention this turning on
of the motive power and of the clutch is made gradual, as will now be understood,
whereby all shocks to the car and injury to the machinery are avoided.
In Figure 3, the speed lock or speed check, shown as applied to the gradual
turning on of an electric current for any purpose whatever.
In this case, 21 repre-
sents a rheostat, 22 the contact plates, 23 the switch arm carrying a contact brush,
as shown, and this arm 23, is actuated by a rack-bar 24, engaging a pinion 25, fast
on the pivoted arm 23. The current may be supposed to enter by the conductor 26,
passing by the arm 23, through the rheostat sections on the right hand side of the
arm, and out by conductor 27. When the rack bar is moved gradually in the
direction of the arrow indicated, resistances are gradually cut out and the current
correspondingly increased. To accomplish this gradual movement of the rack bar
it may be mounted upon a rod 28, guided in a rectilinear path by suitable guides 29,
and actuated by the lever 1, mounted upon the segmental ratchet frame 3, 4, and
provided with the escapement pawl 11, constructed in accordance with the invention;
the lever 1, being jointed to the rod 28 by a link 30.
Instead of using a segmental ratchet, a rectilinear ratchet bar 31 may be used,
arranged parallel to the rod 28, with the escapement pawl 11, mounted upon the
rod. This arrangement will operate exactly the same as a segmental ratchet and
escapement pawl constructed in accordance with the invention, and it will be clear
to those skilled in the art that in all cases where the application of power is to be
positively graduated, a rectilinear ratchet may be used in place of a segmental one.
In Figure 4, the speed lock or speed check is illustrated as applied to a throttle-
valve 32, the spindle of which is connected with a crank 33, jointed by a link 30,
with the lever 1, which is mounted and equipped in the manner shown in Figure 1.
In Figure 5, the invention is shown as applied to the grip of a cable car. In
this case, the segmental ratchet frame with the operating lever, equipped with the
improvement, is mounted upon the platform 34, of the car. The lever in this
instance is a bell-crank lever, and is connected by a toggle link 35, to the movable
member 36, of the grip; the cable 37, passing between the fixed and movable
members of the grip. The advantages of the application of the invention to cable
cars are self evident.
It will be understood, that in the practical application of the speed lock or speed
check, it is of no consequence whether the escapement pawl or the ratchet is
connected with the operating lever or rod, so long as one of them is stationary,
although it is also practicable to move both in opposite directions.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. As a means for controlling an operator in the application of power, the

page_text: combination of power transmitting devices, and a hand lever or rod for actuating
the same; with a rocking escapement pawl preponderating on one side, carried by
said lever or rod, and a ratchet in operative relation to the escapement pawl and
arranged with reference to the same to lock the lever or rod against rapid movement
in one direction, substantially, as described.
2. In electric motor cars, the combination of an electric motor and the lever for
starting the car; with a biassed escapement pawl carried by the lever and a ratchet
in operative relation to the escapement pawl; the two being spaced and shaped
with reference to each other to lock the lever against rapid movement in the
direction for applying the power, substantially, as described.
3. In electric motor cars, the combination of an electric motor, a clutch for
coupling the armature of the motor to the drive axle and for uncoupling the same,
and the lever for admitting current to the motor and for actuating the clutch; with
a ratchet and a pivoted escapement pawl moved by the lever along the ratchet and
oscillated by the ratchet teeth and by gravity to lock the lever against rapid move-
ment in one direction, substantially as described.
4. The combination of a lever for actuating power applying devices; with a
biassed escapement pawl carried by the lever, and a ratchet, both constructed
substantially as described to re-act upon the lever to lock the same against rapid
movement in one direction, substantially as described.
5. The combination of a lever for actuating power applying devices, with an
escapement pawl carried by the lever and a ratchet in operative relation to the
escapement pawl, both spaced and shaped to bring the escapement pawl into abut-
ment with the ratchet, when the lever is moved beyond a predetermined speed in
one direction, substantially as described.
6. A power controlling lever in combination with a speed lock, substantially as
described.
Dated this 18th day of January 1892
WM. P. THOMPSON & Co.,
Agents for the Applicant.