Патент USA US2012943

v Sept. ‘3, l1935.
Hf ARNOLD Er AL
2,012,943
ELECTRIC SWITCH
Filed April 28, 1954
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Sept. 3, 1935.
H.- ARNOLD Er AL
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ELECTRIC
2,012,943
SWITCH
Filed April 28, 1934
2 Sheets-Sheet 2
2,012,943>~
- PatentedD sels.. 3, 1935
UNITED sTATEs PATENT OFFICE
2,012,943
ELECTRIC SWITCH
Heinrich Arnold, Waiblingen, and Erich Dobler,
Stuttgart, Germany, assignors to Robert Bosch
Aktiengesellschaft, Stuttgart, Germany
Application April 28, 1934, Serial No. 723,000
In Germany May 31, 1933
7 Claims. (CL 12B-179)
tact spring I is conductively connected with a
This invention relates to electric switches, and
particularly to a combined switch for controlling
both the ignition system and the starting motor
of an internal combustion engine.
The circuit of an electric glow plug or plugs
for heavy oil engines are usually closed through
a switch before starting the engine and opened
again after starting.
l
In one previous arrangement there is provided
for this purpose a switch with two contact points
through which flrst the glow plug alone and
then it together with the starting motor are con
nected in circuit to the source of current. How
ever, if, upon starting, the battery voltage falls
_ considerably, the glow plug will be supplied with
too little current for proper operation.
One object of the invention is to avoid this
dimculty by providing circuit connectionswhere
by in the first position of the switch, the glow
20 plug is connected in sexies with a resistance, and
in the second position the glow plug together with'
the starting motor are connected in circuit with
only a part of 'the resistance.
Another object is to provide a novel- switch
structure for effecting the above noted double
function.
-
The accompanying drawings disclose by way
'of example one form of the invention.
drawings:
In the
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Fig. l shows a top plan view of the switch box:
Fig. 2 is a longitudinal section taken on line
II-lI of Fig. 1;
llI-III of Fig. 1;
Fig. 4 is a section taken on line IV--IV of Fig. 2;
Fig. 5 is a section on line V-V of Fig.- 2;
Figs. 6 and 'i show details of two stay bolts; and
Fig. 8 is a circuit diagram.
The switch housing I is provided with a bottom
plate 2 of insulating material upon which are
mounted two stationary switch contacts 2, l and
»a contact spring 5. Above the bottom plate 2,
an intermediate plate 9 is held by means of stay
bolts t, 1 and t. Plate 9 carries a resistance
45 formed in two parts Il and II. The resistance
II has a lower value than resistance It and is
constructed in the form of a glow wire positioned
below a transparent window I2 in the upper end
of housing I. The three stay bolts t, 1 and I
are fastened to and insulated from the inter
mediate plate 8 and are connected at their free
ends by means of nuts to the ends of resistances
Iii and li.
,
_
'
On the bottom plate 2, the stay bolts C and ‘I
are electrically connected at 2 and 4. The con-,
5
leading to four glow plugs in series. The ter
minal of the »last glow plug is grounded as shown.
Upon the intermediate plate 9 is fastened a
bushing I5 in which is journaled a switch shaft
I6. A cross pin I1 is set in the latter and extends
into a slot I8 provided in the Wall of the bushing
Il. In a longitudinal bore of the switch shaft IG
is inserted a shaft I9 of a hand lever 20, which
is coupled by means of a detent 2| with the
. switch Shaft I6.
In the bore of the switch shaft I6 and extend
ing through a square opening in the bottom plate
2, is a shaft 22, non-rotatable but longitudinally
moveable against the force of a coil spring 23,
to which shaft is fastened the insulating bushing
24. Upon the latter is provided a. contact arm 25
which coacts with the contact spring 5. The
insulating bushing 2l also carries, under the in
fluence of spring 26, a two stepped contact bridge 25
21 having ends 28 and 29 of different lengths.
The contact arm 25 and the contact bridge 21
are connected by a wire with terminal 3i) ar
ranged exteriorly on the bottom plate 2 to which
is fastened a wire leading to one terminal of bat
tery 32. The other terminal thereof is grounded
as shown.
Fig. 3 is a longitudinal section taken on line
A4,0
terminal 3| on the exterior of the bottom plate 2
from which a lead extends through coil 34 of an
electromagnet to the ground as shown. The stay
bolt 8 extends to a terminal I3 on the exterior
of the bottom plate 2 to which is fastened a wire
.
,
If the switch handle 2li is turned clockwise, the
switch shaft I6, because of slot I8 guidingcross
pin I1, moves downwardly. The shaft 22 is 35
thereby pressed downwardly against the force
of spring 22. The longer end 28 of the contact
bridge 21 thereby touches the switch contact 3
to which the glow plugs I4 are connected through
resistances Iii and II. For thisI switch position
a rest 33 is provided in the oblique slot I8 which
forms a stop for the cross pin I1.
-
If the switch handle 20 is turned farther, the
two shafts I 6 and 22 move farther downward.
The contact bridge 21 is tilted due to, the abut- 45
ment of its long end 28, until its short end 29 is
pressed against the switch contact 4. The re
sistance I0 is thereby short circuited. At the
same time the contact arm 25 rests on the contact
spring l whereby the circuit of the electromagnet
3l is closed. Through the contact bridge 36 of
the latter the circuit of the starting motor I8 is
closed.
~
After starting, the switch lever 20 is turned
backto suchanextentthatthecrosspin I1 lies 55
9,012,943
against the stop 33, so that the glow plugs Il are
ccnneced in series with the resistances Il and I I.
As soon as the engine furnishes its own ignition,
the switch lever 20 is released and thereupon is
l returned automatically by spring 23 to its rest
position in which the circuit of the glow plugs
M is open. For this reason it is not possible for
the operator to inadvertently leave the glow plug
circuit closed after starting.
As long as the glow plugs I4 are in circuit the
window I2 is lighted by the glow of resistance I I.
The operator thus recognizes that the glow plugs
are connected to the battery 32.
,
It will be seen that the switch possesses but a
16 single handle which serves to control the glow
plugs as well as the starting motor. By using a
single switch for both connections, a simple con
struction of the switch box is obtained as well as
of current, and a resistance in the circuit con
nections, said ilrst position connecting the glow
plug in series with the resistance and said second
position disconnecting at least a portion of the
resistance, said switch having a two part shaft,
one part of which is adapted for angular as well
5
as longitudinal adjustment and the other part
of which carries contacts longitudinally adjust
able only.
4. In apparatus for controlling the glow plug 10
and starting motor of an internal combustion en
gine, a source of current, a switch having two
positions, circuit connections whereby in one
position the switch connects the glow plug to the
source of current and in the other position con
nects the glow plug and the motor to the source
ofv current, and a resistance in the circuit connec
tions, said> first position connecting the glow plug
a simple arrangement preventing improper con
in series with the resistance and said second p0
nection of the glow plugs and starting motor.
. sition disconnecting at least a portion of the re
What is claimed is:
.
sistance, said switch having a shaft longitudinal
l. In apparatus for controlling the glow plug ly adjustable by means of an inclined groove with
and starting motor of an internal combustion en
gine, a source of current, a switch having two
positions, circuit connections whereby in one po
sition the switch connects the glow ,plug to the
source of current and in the other position con
nects the glow plug and the motor to the source
of current, and a resistance in the circuit con
nections, said ñrst position connecting the glow
plug in series with the resistance and said second
position disconnecting at least a portion of the
resistance. .
2. In apparatus for controlling the glow plug
and starting motor of an internal combustion en
gine, a source of current, a switch having two
positions, circuit connections whereby in one po
sition the switch connects the glow plug to the
source of current and in the other position con
nects the glow plug and the motor to the source
of current, and a resistance in the circuit con
nections, said ilrst position connecting the glow
plug in series with the resistance and said second
position disconnecting at least a portion of the
. resistance, said switch having a shaft longitudi
nally adjustable against spring pressure and-a
tiltable two position contact bridge for the glow
plug and a contact for the motor.
3. In apparatus for controlling the glow plug
and starting motor of an internal combustion en
gine, a source of current, a switch having two po
sitions, circuit connections whereby in- one posi
tion the switch connects the glow plug to the
source of current and in the other position con
, nects the glow plug and the motor to the source
a rest disposed to form a stop in the closing move
ment of the switch, and also having means to
automatically return the switch to rest position.
5. In apparatus for controlling the glow plug
and starting motor of an internal combustion en
gine, a switch having two positions, a housing for
said switch, a window in said housing, a resistance
in said housing, and circuit connections whereby
all the resistance is connected in one position oi
the switch and a part of the resistance is discon
nected in the second position, said part whichis
connected in said second position being visible
through the window when incandescent.
6. In an electric switch for controlling the glow
plug and starting motor of an internal combus
tion engine, a two part shaft, a handle connected
to one of said parts for angular and longitudinal
adjustment thereof, and contacts carried by said
second part, said second part being longitudinal
ly adjustable only.
7. In an electric switch for controlling the glow
plug and starting motor of an internal combus
tion engine, a shaft, contacts closed by movement 45
of saidv shaft, a member adjacent said shaft hav
ing an inclined- groove, a member attached to '
said shaft adapted to project into said groove
whereby angular movement of said handle is
converted into longitudinal movement of said
shaft, and a rest intermediate the length of said
groove disposed in such manner that it forms a
stop inthe closing movement of the switch.
HEINRICH ARNOLD.
ERICH DOBLER.
.
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