Safety method and apparatus for sensing the presence of individuals adjacent a vehicle
First Claim
1. A method for detecting the proximity of an individual to a vehicle, said vehicle having a detector including a balanced bridge circuit, said bridge circuit including a capacitor formed between earth ground and an electrode which is mounted to the exterior of the vehicle, the method comprising the steps are:
- (a) establishing an electric field between the electrode and earth ground in an area exterior to the vehicle;
(b) automatically sensing bridge circuit unbalance and generating an electrical signal indicative of unbalance;
(c) rebalancing the bridge circuit upon occurrence of said signal at a first rate when the vehicle is in motion;
(d) varying, from the first rate, the rate at which the bridge circuit is rebalanced when the vehicle is stationary;
(e) detecting a change in a capacitance Cd existing between the electrode and earth ground caused by the entry of a body into the field exterior to the vehicle when the vehicle is stationary;
(f) generating a sensory indication when the bridge circuit becomes unbalanced upon entry of a body into the external field when the vehicle is stationary; and
,(g) restoring the rate of rebalancing of the bridge circuit to said first rate as the vehicle proceeds in motion.
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Accused Products
Abstract
An improved safety method and apparatus for sensing individuals adjacent a vehicle utilizes a balanced bridge circuit. The method and apparatus provides for rebalancing the bridge circuit at a first rate during vehicle motion to compensate for topography and environmental changes as the vehicle proceeds and for varying the rate to a second relatively lower rate, and, alternatively inhibiting rebalancing of the bridge circuit when the vehicle is stationary during proximity detection of individuals adjacent the vehicle. A delay in restoring the rebalancing rate to the first rate is provided as the vehicle prepares to proceed. An improved electrode, detection assembly employed in the method and apparatus is described.
65 Citations
20 Claims
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1. A method for detecting the proximity of an individual to a vehicle, said vehicle having a detector including a balanced bridge circuit, said bridge circuit including a capacitor formed between earth ground and an electrode which is mounted to the exterior of the vehicle, the method comprising the steps are:
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(a) establishing an electric field between the electrode and earth ground in an area exterior to the vehicle; (b) automatically sensing bridge circuit unbalance and generating an electrical signal indicative of unbalance; (c) rebalancing the bridge circuit upon occurrence of said signal at a first rate when the vehicle is in motion; (d) varying, from the first rate, the rate at which the bridge circuit is rebalanced when the vehicle is stationary; (e) detecting a change in a capacitance Cd existing between the electrode and earth ground caused by the entry of a body into the field exterior to the vehicle when the vehicle is stationary; (f) generating a sensory indication when the bridge circuit becomes unbalanced upon entry of a body into the external field when the vehicle is stationary; and
,(g) restoring the rate of rebalancing of the bridge circuit to said first rate as the vehicle proceeds in motion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 19, 20)
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9. A proximity detector for detecting the presence of a person about the exterior of a vehicle comprising:
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(a) an electrode mounted exterior to the vehicle and forming a capacitor having a capacitance Cd with earth; (b) a balanced bridge circuit including said capacitor; (c) circuit means for exciting said bridge circuit and establishing an electric field exterior to the vehicle; (d) circuit means responsive to the detection of an unbalance of the bridge circuit for rebalancing the bridge circuit at a first rate when the vehicle is in motion and for varying, from said first rate, the rate at which said bridge circuit is rebalanced when the vehicle is stationary; (e) circuit means for detecting the entry of a body into said electric field when the vehicle is stationary; and
,(f) circuit means for generating a sensory indication upon said entry. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. An electrode assembly for a proximity detector for a vehicle comprising:
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(a) an elongated support body formed of an electrically insulating material; (b) a guard body having a semicircular cross sectional configuration and including an arcuate gap therein; (c) an elongated electrode body mounted to said support body and positioned in said gap; and
,(d) means for mounting said electrode assembly to a surface of the vehicle. - View Dependent Claims (17, 18)
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Specification