Note: Descriptions are shown in the official language in which they were submitted.
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CORD SAVER
FI~LD OF THE INVENTION
; The present invention relates to automobile
accessories and rnore particularly to an accessory useful
in conjunction with automotive starting aids such as
engine heaters, battery chargers and the like.
B~CKGROUND
In cold climates, motor vehicles are conven-
tionally equipped with starting aids such as engine
heaters, battery chargers and the like to ensure that the
vehicle will start when desired. These starting aids
normally operate from conventional electrical mains
power, i.e. 110 volts AC. The connection to mains power
is usually made with an extension cord extendi.ng ~rom the
vehicle to an appropriate rnains outlet.
Often a vehicle operator wi.ll ~orget to dis-
connect the extension cord linking his vehicle and the
outlet and will drive away while the connection is still
made. This may result in a lost or destroyed extension
cord, or, where the cord is anchored to the vehicle, it
can cause vehicle damage, for example the breakage of an
expensive grill.
The objective of the present invention is to
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overcome this problem by preventing the operator from
driving his vehicle while there is an extension cord
linking the vehicle to a mains outlet.
SUMMARY
According to the present invention there is
provided an automobile accessory including connector
means adapted to be connected to an electrical power
outlet and a normally closed switch means adapted to be
connected in a starting circuit for an automobile and
having switch operating means for opening said switch
means to open said starting circuit in response to
connection of the connector means to an electrical power
outlet.
In one embodiment, the accessory consists of a
housing that contains a duplex receptacle connected to a
cord that can be plugged into the end of an extension
cord or an electrlcal outlet. The housing also contains
a relay switch with the relay coil connected in parallel
to the duplex receptac~e and the relay contacts wired
into the starting circuit for the vehicle motor, in
series with the usual starter switch. This means that
while power is being supplied to the duplex receptacle,
the starting circuit for the motor is opened by the relay
switch and the vehicle cannot be started.
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The duplex receptacle is used as ~he power
source for the starting aids.
In another embodiment, the accessory is a
housing with electrical terminal prongs projecting from
it to be plugged into a conventional ~lectrical outlet.
A relay switch in the housing has a coil connected across
the terminal prongs and normally closed contacts con-
nected to terminals or leads, outside of the housing for
connection to the automobile starting circuit. With this
embodiment, the control means plugs into a common exten-
sion cord, with the starting aids.
~` BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate
exemplary embodiments of the present invention:
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Figure 1 is a schematic circuit diagram of one
embodiment of the present invention;
Figure 2 is an isometric view of the accessory
of Figure 1; and
Figure 3 is a schematic diagram of another
embodiment of the present invention.
DETAILED DESCRIPTION
Referring to the accompanying drawings, and
particularly to Figures 1 and 2, there is illustrated an
automobile accessory 10 that includes a housing 12 accom-
;
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modating a conventional duplex receptacle 14. ~he recep-
tacle 14 is connected to a power cord 16 of the type
conventionally used as extension cords for carrying 110
volts AC. Such a cord has two power wires 18 and a
ground wire 20. The duplex receptacle 14 is wired to
these in the conventional way.
The housing 12 also accommodates a relay switch
22. The relay switch has a coil 24 connected in parallel
to the duplex receptacle, across the power wires 18. The
contacts 26 of the relay switch 22 are normally closed
but open when power is applied to the cord 16.
Two wires 28 and 30 lead from the switch
contacts 26 and are connected to a line 32 in the starter
circuit for the automobile engine. The line 32 normally
extends directly from the battery 34 to the coil of the
starter relay 36 and contains the usual starter switch
38. As illustrated in Figure 1, the line 32 is cut at
point 40 and the resultant ends are connected to the ends
of the wires 28 and 30 respectively so that the relay
switch contacts 26 are in series with the starter switch
38.
Figure 2 is a pictorial representation of the
embodiment of ~igure 1. The accessory is housed in a
synthetic plastic housing 12. The duplex receptacle 14
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provides two outlets 42 spaced along one face of the
housing while a power cord 16 exits from one end and the
wires 28 and 30 exit from the other. At the base of the
housing are lugs 44 with elongate slots 46. The lugs
and slots are used ~or fastening the housing to an auto-
mobile with screws or bolts.
For installation the accessory may be mounted
on a vehicle at a convenient location. The wire 32 of
the starter circuit is then cut and connected to the
wires 28 and 30 leading from the housing 12. The various
starting aids are then plugged intG the outlets 42 to
receive power when the plug 48 on cord 16 is connected to
a mains power outlet either directly or through an exten-
sion cord.
When the accessory is plugged into a 110 volt
AC outlet, power is supplied to the coil 24 of the relay
switch 22. This opens the normally closed contacts 26,
breaking the circuit between the vehicle starter switch
38 and the starter relay 36. Because of the open cir-
cuit, the starter will not operate. Unplugging the
accessory 10 from the outlet disconnects the power supply
to the relay coil 24, allowing the contacts 26 to close
and restoring normal starter operation.
Figure 3 illustrates another embodiment of the
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invention in which the accessory has a housing 50 with a
pair of electrical terminal prongs 52 projecting from it.
The prongs are of the type normally used in connecting a
power cord to an electrical outlet. A relay switch 54 in
the housing 50 has its coil 56 connected across the
prongs 52, and its normally closed contacts 58 connected
to a pair of leads 60 for connection to the starter
circuit. This embodiment is wired to the starter circuit
in the same way as the embodiment of Figure 1. In use,
it is plugged, by means of prongs 52, into the source of
power for the various starting aids, normally an exten-
sion cord. The application of power to the cord will
then open the starting circuit.
While two specific embodiments of the present
invention have been described in the fore~oing, it is to
be understood that other embodiments are possible within
the scope of the invention. It is, for example, possible
to employ any suitable nul~ber of receptacles 42 in a
housing 12. The wires 28 and 30 maY be omitted or in-
dependent from the unit as such where appropriate terml-
nals are provided on the housing 12 for connection to the
wire 32 of the starter circuit or to secondary wires
leading thereto. The relay switch 22 may be replaced
with any equivalent device, for exam~le, a solid state
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switch opening in response to the presence of a voltage
across the power wires 18 or between one of the power
wires 18 and the ground wire 20. It is therefore to be
understood that the present invention is intended to be
~ limited solely by the scope of the appended claims.
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