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FIELD OF THE INVENTION
The invention relates to the development of an interlocking circuit of hour
meter preventing faulty recordal of engine running time and wrong fuel
average calculation with respect to time
BACKGROUND OF THE INVENTION
Generally, most of the engines/ generators run based on oil or gas as
operating fuel and automatically interest lies in calculation of average fuel
consumption with respect to time to economise the process.
Clock hour - meter which records the time of running the engine or
generators, is generally connected directly to Battery power through an when
the engine is started the operator puts on the Ignition switch and ignition
switch. Hour - meter starts recording the time of run irrespective of its
running or idle condition as per prior art.

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This happens when the operator or mechanic mistakenly keep the switch in
"ON" position causing wrong fuel average calculation.
In this background, a novel interlocking arrangement has been developed to
run the clock hour - meter only when the engine / generator is in running
condition.
In idle condition of the engine the hour - meter can not be made on pressing
the ignition switch.
OBJECT OF THE INVENTION
- The object of the invention is to develop an interlocking device to restrict
hour - meter to record time when engine / generator is in idle condition.
- Another object of the invention is to restrict starting of the hour-meter
only through ignition switch.

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- Other object of the invention is to maintain a rational reiationship of fuel
consumption with respect to running time of engine / generator.
- Further object of the invention is to use hydraulic oil pressure of the
system only when the engine is in running condition,
- Yet other object of the invention is to develop a simple way to start the
clock hour meter using one NO / NC contact.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Fig - 1. Describes the schematic arrangement of the developed system along
with associated elements z.e pressure sensor, engine oil line, spring charge
bellow, hour meter, NO/ NC contact ignition switch and battery.

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Fig - 2. Describes the schematic arrangement on switching on hour - meter
as per prior art.
DETAI DESCRIPTION OF THE PREFERRED EMBODIMENT
The main embodiment of the invention as described in Fig 1. has been
activation of one (NO) contact attached to the spring charged bellow, by the
Hydraulic pressure developed in engine oil line during running condition of
the engine.
As per prior art the hour meter (1) keeps on functioning even if the engine /
hydraulic system / or equipment are not in operation, while ignition switch
(2') is in 'ON' position as shown in Fig - 2.
Here, the hour - meter gets the power directly from the battery (3) through
ignition switch. This happens when the operator or mechanic keeps the
switch in 'ON' position by mistake, when the engine is not running and the
consumption of fuel is nil.

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In the present invention one NO/ NC contact (4-41) has been in corporated in
the circuit as shown in Fig -1, which is attached to the contact bar (5) of the
spring charged bellow (6).
In this set up the hour meter (1) can not be made on only by pressing the
ignition switch (2) as because the circuit is open due to (NO) contact (4).
The NO contact (4) operate only through the hydraulic oil pressure when
engine oil line (7) is in operation due to running of engine which in turn
activates the Bellow (6) through pressure sensor (8) and the contact bar (5)
moves forward to make the NO (4) contact NC (41). In this condition clock
hour meter (1) can be made on by pressing the ignition switch (2-21) to
record the running time of the engine.
As the engine stops, it no more draws any fuel through the engine oil line (7)
and the Bellow pressure drops automatically with the drop of

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hydraulic oil pressure, the NC contact (41) goes back to its NO contact (4)
position by the spring (9) assisted contact bar (5) and the hour - meter
supply from the battery is disrupted.
Therefore in switch off condition of the engine clock hour meter will not
record any time to misguide average calculation of fuel with respect to time.
SUMMARY OF THE INVENTION
The invention is focussed on correct recording of engine running time with
respect to the fuel consumption of engine.
An interlocking circuit has been developed with the utilisation of change of
hydraulic pressure in the engine oil line when the engine is in running
condition. The supply of battery power to the hour meter is made via one
NO / NC contact irrespective of ignition switch is off or on due to human
error,

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WE CLAIM
1) A novel method of prevention of false recording of hour meter and
development of an interlocking circuit when the engine is in idle condition
as described in Fig -1 comprising:
a) NO / NC contact (4-41) to connect hour - meter to the power supply
battery (3) through ignition switch (2-21).
b) one spring (9) assisted bellow (6) and contact rod (5) moving forward with
the increasing hydraulic oil pressure to make NO contact: (4) NC (41).
c) a pressure sensor (8) to sense the change in hydraulic pressure in engine
oil line (7) and to activate spring assisted bettery to move forward along
with the contact rod (5).

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d) The method as claimed under claim (1), wherein various pressure
setting points (10) adjusted depending on requirements.

The invention is focussed on correct recording of engine running time with respect to the fuel consumption of engine.
An interlocking circuit has been developed with the utilisation of change of hydraulic pressure in the engine oil line when the engine is in running condition. The supply of battery power to the hour meter is made via one NO / NC contact irrespective of ignition switch is off or on due to human error.