An Improved Means for Switching Current, applicable for Electric Motorcars Operated by a Mixed Supply.
Year: 1896

page_text: Date of Application, 27th May, 1896-Accepted, 22nd Aug., 1896
COMPLETE SPECIFICATION.
An Improved Means for Switching Current, applicable for Electric
Motorcars Operated by a Mixed Supply.
I, CLEMENS ADAM of 7 Tulpenstrasse, Hanover in the Empire of Germany,
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 a switch device for those electric motor cars wherein
the current is supplied in sections from the outside and from an accumulator
battery carried on the cars.
In such motor cars it is a question of always rationally distributing the electric
energy. What is necessary is to be able to charge the battery on the section
provided with an outside supply, and to switch it off when the charging is
completed whilst it must also be possible to switch on the battery without essential
loss of current, by means of resistances or the like as soon as the car leaves the
outside supply. Further it must be possible when travelling slowly to switch on
the battery in two series parallel and finally the incandescent lamps provided must
be so arranged that they can bear without damage the high tension charge of the
accumulator and yet give sufficient light at the low tension charge.
It is of course possible to effect "all these various switchings with the switch
apparatus at present known but in such case it would be necessary to have a regular
series of switch levers which would have to be carefully operated by the car
driver. There would result however the great drawback that the car driver might
easily seize the wrong handles thus increasing danger and causing short
circuiting.
On the contrary the present invention affords an extremely simple method or
means of switching current, by means of which both useless consumption of energy
and interruptions in the working caused by seizing wrong handles, short circuiting
and the like are avoided.
The improved method of switching is shown in the accompanying drawings, in
which
Figures 1-4 are diagrammatic views of various positions of the switching
device, and
Figures 5-18 are details.
The improved method of switching is based on the use of two switch drums
coupled in a peculiar manner, one of which operates the switching on or off of the
current during the starting or stopping of the car, the other the switching on of the
batteries in parallel and in series, whilst a main switch assumes various fixed
positions in order to allow of current being sent simultaneously either into the
motor and the batteries, or into the batteries alone, or from the outside conductor
to the motor, or finally from the batteries to the motor.
In the drawing the three switching devices are indicated by the letters A, B
and C. The two switch drums A and B are arranged on a common spindle D with
which the drum A may revolve whilst the drum B is revoluble independently on
said spindle.
Both drums are also connected in a peculiar manner as will be more particularly
described hereinafter.

page_text: The main switch C which is independent of the spindle D comprises two switch
arms and connected by a link i, and contacts c c c c also an arm m attached to
the arm k with contacts m' and m and concentrically arranged contacts of of c
The arrangement is so contrived that the main switch can assume three different
positions, which are shown in Figures 1-4. In the position shown in Figures 1
and 2, the switch arm k rests on the contact c¹ and the switch arm on The
contacts c¹, cand c³, care simultaneously interconnected whilst contacts c³, c, c³, c
are out of contact with the contacts m² m². In the position shown in Figure 3, the
contacts c, c, c7 and 8 are out of contact with the switch arms k and I, whilst
contacts and c are connected by means of the contact piece m¹ and the contacts c
and by the contact piece m. In the position shown in Figure 4, the contacts c'e'
and are out of contact with the switch arms k and 1, while the switch arm k rests
on the contact . Simultaneously the contacts and are connected by the
contact piece m and the contacts cc by the contact piece m².
The connections of the separate contacts and brushes with the halves of the
battery I and II with the outside conductor n, with the two drums A and B,
the armatureo, the field coils p and resistances R1 R2 R R*, and with the
lamps L L L L and L are shown in the drawing and can easily be
understood.
The half battery II must be connected with the switch arm k, but the connection
need not be precisely in the middle as shown in the drawing. In the position of
the main switch in Figures 1 and 2 the switch arm k and the switch arm connect
the free ends of the battery halves in such a way that the battery halves I and II
may be inserted in parallel by means of contact surfaces t t' or switched on in series
by means of a contact surfaces. These contact surfaces will be hereinafter more
particularly described.
The arms & and I are insulated from one another and also the contacts m² m² from
the contact arm k, whilst the upper contact pieces of the contact arms k andare
conductively connected with the said arms. In Figure 1 the current passes from
the one pole of the battery half II through ke bat b¹ to a', from whence it flows
parallel to the current coming from the equivalent pole of the battery half I,
through a ao at to a' p, and then in parallel circuits, in the one case through
to the other pole of 1, and in the other case direct to the corresponding pole
of II.
In Figure 2, the current goes from one pole of the battery half 1 through b² to
arm k and from there to the opposite pole of the battery half II, so that the battery
halves I and II are switched on in series. In Figure 3 the battery is switched off.
In Figure 4 the current passes from one pole of the battery half f through arm k
to the opposite pole of the battery half II, so that again the two battery halves
are switched on in series.
In the position shown in Figure 1 the halves of the battery I and II which are
inserted in parallel, and in the position shown in Figure 2 the halves of the battery,
which are switched on in series, serve for foeding the motor. Simultaneously the
lamps Land Lare connected or switched on to the battery half I, and the
lamps Land L' are switched on to the battery half II, whilst the lamp L' is
cut out.
In the position shown in Figure 3 the battery is quite disconnected. The current
passes from the outside conductor n through the machine to the ground.
Simultaneously lamps L' to L' are in series and are also traversed by the current
from the outside conductor n to the ground.
In the position shown in Figure 4, the current from the outside conductor passes
on the one hand through the machine, and on the other hand through the halves
of the battery I and II (which are switched in by means of the switch arm k) to
the ground. Simultaneously the five lamps in series are in shunt circuit with the
battery.
The relations hereinbefore mentioned remain unchanged for each of the three
positions of the main switch C. At each position of the main switch C however

page_text: two necessary switchings may be effected by means of the drums A and B. The
drums A and B are so connected with one another that the lower drum may be
partially operated by means of the upper drum and is always returned to its zero
position as soon as the upper drum reaches its zero position.
This coupling may be effected in various ways. Figures 6-11 show one form
of construction and Figures 12-18 another. In Figures 6 and 12 the surfaces of
the casing of the drum shown in Figures 5 and 13 are shown diagra.nmatically as
in a plane. The contact surfaces q r s t t are arranged in the manner shown in
Figures 6 and 12.
The contact brushes a-a8 and - (Figures 1 to 4) rub on these contact surfaces,
said brushes lying in a straight line one above the other. The separate positions
of the drums are shown by dotted lines 0, 1, 2, 3, 4, 5 and 6 (Figures 6 and 12) in
which the brushes a-as and are in contact with the drums A and B.
Figure 1 corresponds to position 5 in which the halves of the battery are switched
on in parallel and the resistances R-R are short circuited. Figure 2 corresponds
to the position 6 in which the battery halves are inserted in series, the resistances
being also short circuited. Figure 3 corresponds to position 3 and Figure 4 to
position 1.
The drum A is revolved by means of a crank handle z, Figures 5 and 13; the
movement of the drum A is limited however by a pin ¹ and a stop so that the
position 0 can only be reached from any other position by turning the crank =
backwards.
In the coupling shown in Figures 5-11 a projection is formed on the drum B.
A spring e provided with a tooth a is attached to the drum A so that on the
rotation of the drum A in the direction of the arrow, the tooth a will engage behind
the projection b and carry the drum B with it. On a rotation in an opposite
direction, the tooth a cannot engage with the projection b. On the drum Ba
toothed segment d is also mounted with which a toothed sector e revolubly mounted
between the two drums engages. The toothed sector e is attached to the drum
case and is under the action of a spiral spring which has a tendency to maintain
the same in the position shown in Figures 8, 9 and 10. On a rotation of the drum
in the direction of the arrow (Figure 8) a tooth g on the spring slips over the
point of the toothed sector e but on its being rotated in an opposite direction, the
tooth g revolves the tooth piece or rack e and thereby also the drum B in an
opposite direction.
If the drum A be revolved in the direction of the arrow (Figure 8) the hook a
engages behind the projection of the lower drum and carries the latter with it.
The positions 1-6 are therefore simultaneously attained by both drums. Shortly
before position 6 is attained the tooth g slips over the point of the rack e and
simultaneously the toothed segment d engages with the toothed sector e (Figure 10).
On the drum being turned in a backward direction from position 6 the tooth g
turns the toothed sector e. As however the latter engages in the segment d, the
drum B is again revolved in the direction of the arrow until it reaches the
position 0 (Figure 11). The tooth g then slips off the point of the toothed
sector e, and the latter is turned back by a spiral spring into the position shown in
Figures 8-10. As soon as the drum A is turned back again into the zero position,
the hook a again snaps into engagement with the projection b (Figure 8) so that
the movement can commence afresh.
In the coupling shown in Figures 12-18 a claw w with a pawl is revolubly
mounted on the drum A. The pawl c, which is firmly connected with the claw w,
slides over the surface of the projection v of the drum B, whilst on the surface of a
projection u slides a pawl y', which is revolubly mounted on a fixed arm y. The
mainshaft or spindle D passes through the arm y arranged between the drums A
and B and fastened on the drum casing.
The arm y is provided with a projection y2 on which the claw w slides during a
portion of its movement. In the position shown in Figure 15 the pawl y', which

page_text: stands under the action of a spring, engages behind the shoulder or notch of the
projection u whilst the pawl engages the shoulder or notch of of the projection v.
On a rotation of the drum A. in the direction of the arrow, the drum B is carried
with it by means of the pawl until the claw to is raised by the projection y³, which
takes place after the drums have reached the position I. By the raising of the
claw w, the pawl is released from the shoulder or notch e, whilst the pawl y'
snaps into engagement with the notch 2 (Figure 16).
On the drum being further rotated, the claw w slides on the projection y2 until
the drum A attains position 5. As the pawl is raised the drum B remains
stationary during this time (Figure 17) but shortly before this position is reached
the claw w slips off the projection y2 and the pawl a engages in the notch v². On
the further rotation of the drum A, therefore, the drum B is again carried with it
until the two drums have reached the position 6. In this position the pawl y' snaps
into a notch u³ (Figure 18). A chain or cord b' engages on the drum B in such a
way that the spring 62 is stretched when the drum B is rotated in the direction of
the arrow. If the drum A be then turned back to zero, the drum B is first held
stationary because of the pawl y' engaging in the notch u³. The claw w slips over
the projection y2 and finally encounters with its edge w¹ the roller w3 of the pawl y',
whereby the latter is released from the notch us and is maintained in the position
shown in Figure 16. In this position of the claw w, the spring 6 comes into
action and turns the drum B back into zero position in which the pawl again
encounters the shoulder or notch (Figure 15) and the operation can re-
commence.
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 electric motor cars having power supplied partially from an outside
conductor and partially from an accumulator battery charged during the journey:
a means for switching the current, comprising a main switch (C) the various
positions of which determine whether current is taken from the battery or from
the outside conductor or whether in the latter case the battery is to be simulta-
neously charged, and two interconnected switch drums (A and B) adapted the
one (A) to switch the current as regards the motor and resistances, and the
other (B) to switch the batteries in parallel or in series, said drums being so
connected with one another that each can execute its necessary movements
but both must return simultaneously to the zero position, substantially as
described.
2. In a current switching device such as described, the connection of the two
switching drums (A and B) by means of a projection (b) and spring hook (a), and
by means of a toothed segment (d) and a toothed sector (e) revolubly mounted in
the drum casing and spring hook (g), said spring hooks (a and g) being attached to
the one drum (A) by means of springs (c and h) and the projection (b) and
toothed segment (d) being attached to the other drum (B) substantially as
described.
3. In a current switching device such as described, the connection of the two
switch drums (A and B) by means of a claw (w) and pawl (a) revolubly mounted
on the one drum (A) and adapted to engage the shoulders or notches (vv) of a
projection (v) on the other drum (B), the latter being stopped by means of a
pawl (y) revolubly mounted on the drum casing and so influenced by a spring (6²)
as to return to its zero position when by the backward movement of the drum (A)
the edge (w) of the claw (w) encounters a roller (w²) on the said pawl (y¹)
substantially as described.
4. In a current switching system such as described, the connection of 5 lamps
with a main switch (C) and with conductors, in such a way that during the charging
of the batteries and during the supply of current from the outside all five lamps

page_text: are switched in series and parallel to the motor or to the battery, whilst on the
discharging of the battery each two lamps are connected with each half battery,
substantially as described.
Dated this 26th day of May 1896.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.