Self-adjusting proximity detecting apparatus

Claim 2

In a system for a vehicle having a door for opening and closing a doorway in said vehicle, a door operating mechanism for moving said door in the opening and closing directions through cycles of operation from the closed position to the opened position and back to the closed, antenna means and associated circuitry mounted in that edge of the door which leads it when moving in the closing direction, said antenna means and associated circuitry operating from a balanced to an unbalanced condition in response to the presence of objects proximate said antenna means, the degree of said unbalance varying directly with the capacitance of said objects to ground and the proximity of said objects to said antenna means, protective equipment operable in response to a predetermined degree of unbalance during movement of said door in the closing direction to cause said door operating mechanism to interrupt said movement, the improvement comprising limiting circuitry operating in response to a particular degree of unbalance during the initial opening movement of said door in any cycle of operation and limiting the operation of said protective equipment in causing said door operating mechanism to interrupt movement of said door in the closing direction dUring that cycle of operation to operation in response to changes in the unbalanced condition from said particular degree of unbalance equal in magnitude to the difference between said predetermined degree of unbalance and said balanced condition.

Claim 3

In a vehicle system according to claim 1, wherein said antenna means and associated circuitry include a bridge circuit and amplifying circuits producing detection signals whose magnitudes directly signify the degrees of said unbalances, wherein said limiting circuitry receives said detection signals from said amplifying circuits and in response thereto produces operating signals which are applied to said protective equipment, and wherein said protective equipment operates to cause said door operating mechanism to interrupt movement of said door in response to an applied operating signal exceeding a predetermined magnitude during closing movement of said door.

Claim 4

In a vehicle system according to claim 2, wherein said limiting circuitry includes a feedback signal generator operating during the initial movement of the door in the opening direction in each cycle of door operation in response to the reception by said limiting circuitry of a detection signal in excess of a particular magnitude from said amplifying circuits and producing a respective feedback signal which offsets the effect of said excess signal on said limiting circuitry and prevents said circuitry from producing in response to said excess signal a signal for application to said protective equipment during movement of said door in the closing direction in that cycle of door operation.

Claim 5

In a vehicle system according to claim 3, wherein said limiting circuitry includes resetting means operating in response to each return of said door to the closed position to cease production of the offsetting feedback signal then being produced by said feedback signal generator.

Claim 6

In a vehicle system according to claim 4, wherein said protective equipment is operable in response to an input signal exceeding a predetermined magnitude during closing movement of said door to cause said operating mechanism to reverse the movement of said door and wherein said limiting circuitry includes control circuitry which operates in response to said door reaching the opened position and prevents said feedback signal generator from producing an increased offsetting feedback signal in response to detection signals from said amplifying circuits during closing movement and during reversals notwithstanding the magnitudes of the detection signals produced during closing movement and during reversals exceed that of the detection signal produced during the original opening movement portion of the door operating cycle during which said closing movement and said reversals occur.

Claim 7

In a vehicle system according to claim 5, wherein said feedback signal generator includes a digital signal generator operating in response to excess signals and generating signals which signify in digital form the magnitude of the offsetting feedback signal to be produced and wherein said feedback signal generator also includes a digital to analog signal converter operating in response to said digital signals and producing said offsetting feedback signals.

Claim 8

In a vehicle system according to claim 6, wherein said digital signal generator is a binary counter which increases the magnitude of its generated signal in increments until the offsetting feedback signal produced during any cycle of door operation prevents the excess signal produced during that cycle from producing a signal for application to said protective equipment.

Claim 9

In a vehicle system according to claim 7, wherein said limiting circuitry includes a differential amplifier which receives both said amplifying circuits signals and said offsetting feedback signals, said differential amplifier operating in response to an excess signal and producing a signal which causes said digital signal generator and said converter to produce an offsetting feedback signal Whose magnitude offsets the effect of said excess signal and prevents said differential amplifier from producing a signal in response to said excess signal.

Claim 10

In a vehicle system according to claim 1, wherein said antenna means includes a main portion and a compensating portion, wherein said associated circuitry includes amplifying circuits for each said portion, said amplifying circuits producing output signals whose magnitudes are substantially equal in the absence of a suitable circuit to ground within said predetermined proximity of said antenna means and producing output signals whose magnitudes are unequal in the presence of such a circuit within said predetermined proximity, wherein said limiting circuitry receives output signals from said amplifying circuits and in response to unequal ones produces operating signals which are applied to said protective equipment, and wherein said protective equipment operates to cause said door operating mechanism to interrupt movement of said door in response to an operating signal in excess of a predetermined magnitude during closing movement of said door.

Claim 11

In a vehicle system according to claim 9, wherein said limiting circuitry includes a feedback signal generator operating during the initial movement of the door in the opening direction in each cycle of door operation in response to an operating signal in excess of a particular magnitude produced in response to a specific inequality in the output signals of said amplifying circuits and producing a respective feedback signal which is applied to said limiting circuitry and reduces the magnitude of said operating signal to said particular magnitude throughout that cycle of door operation provided said specific inequality in the output signals of said amplifying circuits continues to exist.

Claim 12

In a vehicle system according to claim 10, wherein said feedback signal generator maintains the magnitude of the feedback signal it produces in response to a specific inequality during the initial movement of the door in the opening direction in each cycle of door operation at that magnitude throughout that cycle notwithstanding the specific inequality increases during movement of said door in the closing direction during that cycle.

Claim 13

In a vehicle system according to claim 11, wherein the amplifying circuits for each portion of the antenna means includes a field effect transistor whose gate is electrically connected to the associated portion of said antenna means.

Claim 14

In a vehicle system according to claim 12, wherein said limiting circuitry includes a differential amplifier which produces said operating signals in response to the output signals of one of said amplifying circuits which it receives at its inverting input and the output signals of the other of the amplifying circuits at its non-inverting input, whereby said operating signals may be of either polarity and wherein said feedback signal generator operates in response to a positive polarity operating signal to apply a feedback signal to the inverting input of said differential amplifier and operates in response to a negative polarity operating signal to apply a feedback signal to the non-inverting input of said differential amplifier.

Claim 15

In a vehicle system having a vehicle with a door for opening and closing a doorway in said vehicle, a door operating mechanism for moving said door in the opening and closing directions, antenna means and associated circuitry mounted in that edge of the door which leads it when moving in the closing direction, said antenna means and associated circuitry being responsive to the capacitance to ground of objects proximate said leading edge to produce output signals whose magnitudes vary directly in relation to the magnitude of said capacitance and the proximity of said objects to said leading edge, protective equipment responsive to input signals in excess of a predetermined magnitude during movement of said door in the closing direction and causing said door operating mechaniSm to reverse said movement, the improvement comprising limiting circuitry receiving the output signals of said antenna means and associated circuitry and applying input signals to said protective equipment, said limiting circuitry responding during movement of said door in the opening direction to that portion of the output signal of said antenna means and its associated circuitry in excess of a particular magnitude and producing an offsetting signal which is applied to said limiting circuitry and offsets the effect of said excess signal on said limiting circuitry thereby preventing said circuitry during the subsequent movement of said door in the closing direction from producing an output signal in response to said excess signal, said limiting circuitry including control circuits which operate in response to the original movement of said door in the opening direction during each cycle of door operation and prevent said limiting circuitry from increasing its offsetting signal during a particular cycle of door operation after the cessation of the original opening movement during that cycle notwithstanding the magnitude of the output signal produced by said antenna means and associated circuitry later during that cycle may exceed the magnitude of such output signal produced during the original movement in the opening direction in that cycle.

Claim 16

In a vehicle system having a vehicle with a door for opening and closing a doorway in said vehicle, a door operating mechanism for moving said door in the opening and closing directions, antenna means and associated circuitry mounted in that edge of the door which leads it when moving in the closing direction, said antenna means and associated circuitry being responsive to the capacitance to ground of objects proximate said leading edge to produce output signals whose magnitudes vary directly in relation to the magnitude of said capacitance and the proximity of said objects to said leading edge, protective equipment responsive to input signals in excess of a predetermined magnitude during movement of said door in the closing direction and causing said door operating mechaniSm to reverse said movement, the improvement comprising limiting circuitry receiving the output signals of said antenna means and associated circuitry and applying input signals to said protective equipment, said limiting circuitry responding during movement of said door in the opening direction to that portion of the output signal of said antenna means and its associated circuitry in excess of a particular magnitude and producing an offsetting signal which is applied to said limiting circuitry and offsets the effect of said excess signal on said limiting circuitry thereby preventing said circuitry during the subsequent movement of said door in the closing direction from producing an output signal in response to said excess signal, said limiting circuitry including control circuits which operate in response to the original movement of said door in the opening direction during each cycle of door operation and prevent said limiting circuitry from increasing its offsetting signal during a particular cycle of door operation after the cessation of the original opening movement during that cycle notwithstanding the magnitude of the output signal produced by said antenna means and associated circuitry later during that cycle may exceed the magnitude of such output signal produced during the original movement in the opening direction in that cycle.

Claim 17

In a vehicle system according to claim 14, wherein said limiting circuitry includes an input circuit and a memory circuit, said input circuit receiving the excessive output signals of said antenna means and associated circuitry and in response thereto applying operating signals to said memory circuit, said memory circuit producing said offsetting signals in response to said operating signals and applying said offsetting signals to said input circuit causing said input circuit to cease to produce said operating signals, said memory circuit maintaining an offsetting signal at the magnitude produced during movement in the opening direction in a particular cycle of door operation throughout the remainder of that particular cycle of door operation notwithstanding said input circuit ceases to produce the operating signal which caused the production of said offsetting signal.

Claim 18

In a vehicle system according to claim 15, wherein said memory circuit includes resetting means responsive to the completion of each cycle of door operation to cease the production of the offsetting signal it is then producing.