Title of Invention	A PEDAL OPERATED INPUT TRANSDUCER FOR ELECTRIC ROAD VEHICLES AND OTHER DEVICES
Abstract	The present invention relates to a pedal operated input transducer for electric road vehicles and other devices which use variable frequency and/or variable voltage drives comprising a load cell (4) based pressure transducer of suitable capacily mounted in a levered assembly (3) connected to the operator's pedal connected to levered assembly (3) through a system of linkages or mechanical cables, said assembly is a spring loaded piston (2) and cylinder (1) placed directly under the operator's pedal or a more sophisticated system of linkages and/or cables, optionally a voltage or power amplifier to bring the values within the range desired by the electronic drive's (5) circuit optionally an A/D converter to make the system more sophisticated by enabling the provision of a proportional digital output.

Title of Invention

A PEDAL OPERATED INPUT TRANSDUCER FOR ELECTRIC ROAD VEHICLES AND OTHER DEVICES

Abstract

The present invention relates to a pedal operated input transducer for electric road vehicles and other devices which use variable frequency and/or variable voltage drives comprising a load cell (4) based pressure transducer of suitable capacily mounted in a levered assembly (3) connected to the operator's pedal connected to levered assembly (3) through a system of linkages or mechanical cables, said assembly is a spring loaded piston (2) and cylinder (1) placed directly under the operator's pedal or a more sophisticated system of linkages and/or cables, optionally a voltage or power amplifier to bring the values within the range desired by the electronic drive's (5) circuit optionally an A/D converter to make the system more sophisticated by enabling the provision of a proportional digital output.

Full Text	This invention relates to a pedal operated input transducer for electric road vehicles and other devices, which use variable frequency and/or variable voltage drives. More particularly the invention relates to the concept for a solid state input transducer for electric road vehicles and other devices which use variable frequency and/or variable voltage drives, The purpose of the input signal transducer, is to provide the drive computer with an analog or digital signal, either in proportion to a voltage or current generated due to a remote activity of the operator. As per the state of the art, such a transducer would be film or wire wound potentiometer attached mechanically to the operator's foot pedal. Depression of the pedat would cause the resistance value of the potentiometer to change. A reference voltage when placed across the 'pot's terminals would show a corresponding change at the slider tap. Any potentiometric device output, however, cannot be reliable due to its reliance on a sliding contact, which has a tendency to introduce its own, unpredictable 'contact resistance1 to the desired value. Further, due to frequency of usage, the sliding contact tends to 'wear away' very soon and the whole component generally needs to be replaced every few months. It is the object of the invention to suggest a concept for a solid state device, which overcomes the shortcomings of a sliding contact, and provide the basis of a design that does away with all electrically active moving parts and provides a driftless. Vibration proof, stable output which varies linearly with the depression of the operator's pedal and which can be easily interpreted by the electronic drive, which it is meant to influence. It is proposed to use a load cell (I) based pressure transducer of suitable capacity. This transducer would be mounted in a levered assembly connected to the operator's pedal through a system of linkages or mechanical cables. In its simplest form, the assembly could be just a spring loaded piston and cylinder(2) placed directly under the operator's pedal(3). The piston would compress a spring when the operator depresses his pedal. The other end of the spring rests on the load cell. Thus the load cell is subjected to a pressure proportional to the depression of the pedal. The crystal structure of the material of the load cell, undergoes a reversible change on the application of pressure and it presents a resistance which varies linearly with pressure applied to it. This variable resistance of the load cell can be used by passing a milli ampere current through it to generate a variable milli voltage. Conversely, the load cell can be subjected to a fixed milli voltage which will give rise to a variable milli ampere current. The variable voltage or current so generated above varies linearly in response to the depression of the operator's pedal. These can be amplified, using standard voltage or power amplification techniques(4) to bring the values within the range desired by the electronic drive's input circuit. Installation of an A/D converter will make the system more sophisticated and would then provide a proportional digital output. This aspect could be particularly useful in precision systems requiring feedback and error correction. The power for this transducer amplifier unit should ideally be drawn from the reference power supply voltages 'built into' the electronic drive to be controlled. This will eliminate inter device source variations and lead to more consistent results. STATEMENT OF INVENTION: Accordingly the present invention provides a pedal operated input transducer for electric road vehicles and other devices which use variable frequency and/or variable voltage drives comprising a load cell (4) based pressure transducer of suitable capacily mounted in a levered assembly (3) connected to the operator's pedal connected to levered assembly (3) through a system of linkages or mechanical cables, said assembly is a spring loaded piston (2) and cylinder (1) placed directly under the operator's pedal or a more sophisticated system of linkages and/or cables, optionally a voltage or power amplifier to bring the values within the range desired by the electronic drive's (5) circuit optionally an A/D converter to make the system more sophisticated by enabling the provision of a proportional digital output. I claim :- 1. A pedal operated input transducer for electric road vehicles and other devices which use variable frequency and/or variable voltage drives comprising a load cell (4) based pressure transducer of suitable capacily mounted in a levered assembly (3) connected to the operator's pedal connected to levered assembly (3) through a system of linkages or mechanical cables, said assembly is a spring loaded piston (2) and cylinder (1) placed directly under the operator's pedal or a more sophisticated system of linkages and/or cables, optionally a voltage or power amplifier to bring the values within the range desired by the electronic drive's (5) circuit optionally an A/D converter to make the system more sophisticated by enabling the provision of a proportional digital output. 2. A pedal operated input transducer for electric road vehicles and other devices which use variable frequency and/or variable voltage drives such as herein before described with reference to the drawings.

Full Text

This invention relates to a pedal operated input transducer for electric road vehicles and other devices, which use variable frequency and/or variable voltage drives.
More particularly the invention relates to the concept for a solid state input transducer for electric road vehicles and other devices which use variable frequency and/or variable voltage drives, The purpose of the input signal transducer, is to provide the drive computer with an analog or digital signal, either in proportion to a voltage or current generated due to a remote activity of the operator.
As per the state of the art, such a transducer would be film or wire wound potentiometer attached mechanically to the operator's foot pedal. Depression of the pedat would cause the resistance value of the potentiometer to change. A reference voltage when placed across the 'pot's terminals would show a corresponding change at the slider tap.
Any potentiometric device output, however, cannot be reliable due to its reliance on a sliding contact, which has a tendency to introduce its own, unpredictable 'contact resistance1 to the desired value.
Further, due to frequency of usage, the sliding contact tends to 'wear away' very soon and the whole component generally needs to be replaced every few months.
It is the object of the invention to suggest a concept for a solid state device, which overcomes the shortcomings of a sliding contact, and provide the basis of a design that does away with all electrically active moving parts and provides a driftless. Vibration proof, stable output which varies linearly with the depression of the operator's pedal and which can be easily interpreted by the electronic drive,
which it is meant to influence.
It is proposed to use a load cell (I) based pressure transducer of suitable capacity. This transducer would be mounted in a levered assembly connected to the operator's pedal through a system of linkages or mechanical cables.
In its simplest form, the assembly could be just a spring loaded piston and cylinder(2) placed directly under the operator's pedal(3). The piston would compress a spring when the operator depresses his pedal. The other end of the spring rests on the load cell. Thus the load cell is subjected to a pressure proportional to the depression of the pedal.
The crystal structure of the material of the load cell, undergoes a reversible change on the application of pressure and it presents a resistance which varies linearly with pressure applied to it.
This variable resistance of the load cell can be used by passing a milli ampere current through it to generate a variable milli voltage. Conversely, the load cell can be subjected to a fixed milli voltage which will give rise to a variable milli ampere current.
The variable voltage or current so generated above varies linearly in response to the depression of the operator's pedal. These can be amplified, using standard voltage or power amplification techniques(4) to bring the values within the range desired by the electronic drive's input circuit.
Installation of an A/D converter will make the system more sophisticated and would then provide a proportional digital output. This aspect could be particularly useful in precision systems requiring feedback and error correction.
The power for this transducer amplifier unit should ideally be drawn
from the reference power supply voltages 'built into' the electronic drive to be controlled. This will eliminate inter device source variations and lead to more consistent results.
STATEMENT OF INVENTION:
Accordingly the present invention provides a pedal operated input transducer for electric road vehicles and other devices which use variable frequency and/or variable voltage drives comprising a load cell (4) based pressure transducer of suitable capacily mounted in a levered assembly (3) connected to the operator's pedal connected to levered assembly (3) through a system of linkages or mechanical cables, said assembly is a spring loaded piston (2) and cylinder (1) placed directly under the operator's pedal or a more sophisticated system of linkages and/or cables, optionally a voltage or power amplifier to bring the values within the range desired by the electronic drive's (5) circuit optionally an A/D converter to make the system more sophisticated by enabling the provision of a proportional digital output.

I claim :-
1. A pedal operated input transducer for electric road vehicles and
other devices which use variable frequency and/or variable
voltage drives comprising a load cell (4) based pressure
transducer of suitable capacily mounted in a levered assembly
(3) connected to the operator's pedal connected to levered
assembly (3) through a system of linkages or mechanical cables,
said assembly is a spring loaded piston (2) and cylinder (1)
placed directly under the operator's pedal or a more
sophisticated system of linkages and/or cables, optionally a
voltage or power amplifier to bring the values within the range
desired by the electronic drive's (5) circuit optionally an A/D
converter to make the system more sophisticated by enabling the
provision of a proportional digital output.
2. A pedal operated input transducer for electric road vehicles and
other devices which use variable frequency and/or variable
voltage drives such as herein before described with reference to
the drawings.

Documents:

951-del-2000-abstract.pdf

951-del-2000-claims.pdf

951-del-2000-correspondence-others.pdf

951-del-2000-correspondence-po.pdf

951-del-2000-description (complete).pdf

951-del-2000-drawings.pdf

951-del-2000-form-1.pdf

951-del-2000-form-18.pdf

951-del-2000-form-2.pdf

951-del-2000-form-3.pdf

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Patent Number

250343

Indian Patent Application Number

951/DEL/2000

PG Journal Number

52/2011

Publication Date

30-Dec-2011

Grant Date

27-Dec-2011

Date of Filing

23-Oct-2000

Name of Patentee

RAJEEV AGRAWAL

Applicant Address

B4/58 SAFDARJANG ENCLAVE NEW DELHI-110029 INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	RAJEEV AGRAWAL	B4/58 SAFDARJANG ENCLAVE NEW DELHI-110029 INDIA.

PCT International Classification Number

B60K

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA