Control lever for heavy machinery with near-proximity sensing

Electrical transmission or interconnection systems – Personnel safety or limit control features

Reexamination Certificate

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Details

C307S009100, C307S328000

Reexamination Certificate

active

06501198

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a control lever for heavy machinery and, more particularly, to a control lever for heavy machinery including a safeguard against inadvertent operation using near-proximity sensing.
Many types of equipment utilize joysticks, twist grips, paddles and other types of hand-operated levers for controlling machine motion. Because of the potential consequences of accidentally or inadvertently operating a lever, it may be advisable for manufacturers to provide safeguards against such events. These safeguards are typically achieved by requiring the operator to perform a sequence of movements or selections that indicate the operator's intent to control the machine before the lever will cause machine motion. Although a single additional activity has been common, some regulations are now requiring two levels of safeguard against unintended motion.
Conventional types of mechanisms that reduce the likelihood of inadvertent motion used in the industry include foot switches, enable switches, trigger switches and the like. These switches are used in combination to achieve two-level safeguards when required. Each of these mechanisms, however, has disadvantages.
A foot switch works well in that both of the operator's hands are free to perform other functions. A foot switch, however, is not practical if the control console, which incorporates the hand levers, must be moved from place to place for convenience of operation or security. Moreover, the foot switch is an electromechanical device, subject to mechanical and environmental failure and tampering.
An enable switch must be continuously held on with one hand while the control is being operated with the other, or must be momentarily selected to activate a timing circuit to provide power to the lever-operated controller. The continuous-hold type switch has a major disadvantage in any type of equipment where both hands are used to perform multiple simultaneous functions. The momentary contact type switch has a disadvantage of requiring a compromise in the length of time that the controls are enabled after pressing the switch.
A trigger switch is built into a hand lever and is activated by gripping a lever handle. Because releasing the switch normally turns off all power to the controller, the machine and its components may come to an abrupt stop if the switch is released. Therefore, the operator must retain a firm grip on the trigger switch while at the same time controlling machine motion in several directions. The resulting operation may be awkward and tiring for the operator.
A mechanical lock may be incorporated into a lever assembly that is designed to automatically snap into the locked position when the lever is released. The lock must then be moved out of the locked position to allow the lever to be moved from its neutral position. A disadvantage of mechanical locks is that the control lever often must survive use in harsh environmental conditions, with parts including small springs and sliding pieces of a locking mechanism that may stick in the unlocked position.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide equipment for guarding against unintended motion of a hand-operated control lever for heavy machinery without the disadvantages of foot switches, enable switches, trigger switches, mechanical locks and the like. Unintended machine motion may be caused by a variety of circumstances, including an operator brushing against a lever with his back turned, by catching a lever with a tool belt, or by a piece of material falling on the lever, etc. With an operator's hand properly placed on or around the lever, it can be assumed that the operator intends to operate the machine. Thus, by sensing, without contact, the presence of an operator's hand in a proper operating position on the control lever, a guard against inadvertent motion can be provided without requiring additional efforts on the part of the operator.
In an exemplary embodiment of the invention, a control lever for heavy machinery includes a control implement and a proximity sensor disposed adjacent an operating position of the control implement. The control implement is coupled with a controller circuit that effects control and operation of the heavy machinery. The controller circuit drives components of the heavy machinery according to movements of the control implement. The proximity sensor includes a sensing circuit communicating with the controller circuit that detects an operator's hand in an operating position on the control implement in accordance with a capacitance of the operator's hand. The sensing circuit outputs an activate signal to the controller circuit when the operator's hand is in the operating position on the control implement, thereby reducing the likelihood of inadvertent activation of the heavy machinery components.
The proximity sensor is preferably embedded in the control implement, spaced from an exterior surface of the control implement at least 0.1″. Alternatively, the proximity sensor may be disposed covering the control implement. In yet another alternative, the proximity sensor is molded in a self-skinning urethane foam grip of the control element.
In accordance with another aspect of the invention, a method of reducing the likelihood of inadvertent operation of heavy machinery includes (a) providing a control implement coupled with a controller circuit that effects control and operation of the heavy machinery, with the control circuit driving components of the heavy machinery according to movements of the control implement; (b) disposing a proximity sensor adjacent an operating position of the control implement, the proximity sensor including a sensing circuit communicating with the controller circuit; and (c) detecting an operator's hand in an operating position on the control implement in accordance with a capacitance of the operator's hand, and outputting an activate signal to the controller circuit when the operator's hand is in the operating position on the control implement.


REFERENCES:
patent: 3177481 (1965-04-01), Joy et al.
patent: 3833898 (1974-09-01), Wilkinson
patent: 4106810 (1978-08-01), Barecki
patent: 4156575 (1979-05-01), Konig et al.
patent: 4412268 (1983-10-01), Dassow
patent: 4489805 (1984-12-01), Okabe
patent: 4526055 (1985-07-01), Batchelor et al.
patent: 4656461 (1987-04-01), Morsch et al.
patent: 4738417 (1988-04-01), Wenger
patent: 4792052 (1988-12-01), Okuda et al.
patent: 4794273 (1988-12-01), McCullough et al.
patent: 5207481 (1993-05-01), Ayala, Jr. et al.
patent: 5328128 (1994-07-01), Morris
patent: 5341036 (1994-08-01), Wheeler et al.
patent: 5380983 (1995-01-01), Cavada et al.
patent: 5396222 (1995-03-01), Markus et al.
patent: 5498914 (1996-03-01), De Boer
patent: 5844204 (1998-12-01), Cubizolles et al.
patent: 5860488 (1999-01-01), Kim
patent: 6102022 (2000-08-01), Schave
patent: 6218947 (2001-04-01), Sutherland
patent: 43 44 187 (1995-06-01), None
patent: 0 701 917 (1996-03-01), None
QProx™ QT110 Charge-Transfer Touch Sensor Operating Manual, Quantum Research Group Ltd., 1999, 12 pgs.

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