Switch apparatus requiring the hand of the operator to activate the switch by breaking a light beam

Abstract

A manually operable switch apparatus for a machine having at least one mode of operation actuated by a control circuit includes a spaced pair of switches which are simultaneously manually operable without the application of exertive contact by an operator. Preferably, each switch includes an infrared emitter spaced from an infrared receiver, and a single or double pole, double throw relay actuated when the beam between the emitter and receivers are broken, so as to cause actuation of an alternative mode of machine operation. The use of switches which do not require exertive contact obviates the injury to wrist and finger tendons experienced by machine operators when conventional palm buttons are employed on machines requiring repetitive operator manipulations. The use of a spaced pair of such switches requires that the operator place both hands on the switches in order to operate the machine, so that the operator cannot inadvertently place a hand in or adjacent to the machine during operation, thus serving to prevent injury to the worker. Such a switch apparatus is substantially more reliable then conventional mechanical and pneumatic switches, subject to significantly less breakdown in use.

Description

This is a continuation of

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE PRESENT INVENTION

With reference first to FIG. 1, the manually operable switch apparatus of the present invention is thereshown positioned on the front of a machine 10 and first comprises a pair of actuation switches 11 and 12. The actuation switches 11 and 12 are characterized by being manually operable without the application of exertive contact against them. For example, the switches 11 and 12 are operable by the insertion of the fingers 14 of a machine operator into a slot 16 formed in each of the actuation switches 11 and 12. Upper edges 21, 23 are angled inwardly toward sides 17 to guide the operator to activate the switch 11, 12 in a non-exertive position. By creating a slot 16 having a generally U-shaped opening, with sides 17 vertically extending a height equal to or greater than the base length, the operator's fingers 14 are positioned in such a way as to prevent any repetitive physical strain upon the tendon in the wrist and/or fingers of the operator. When the beams are broken substantially simultaneously, as required by the control means and logic circuitry 122, the coil 32 of each switch 11 and 12 moves the relay contact 36 from its normal contact with the first circuit contact 37 into contact with the second circuit contact 39, so as to first break the first mode circuit 38, deenergizing the limb 116. Each relay contact 36 then contacts the second circuit contact 39, so as to complete or make the second actuation circuit 40, and energize the second limb 120, thereby causing the control means and logic circuitry 122 to operate the machine in its second mode of operation.

The machine 10 is preferably returned to its first mode of operation in any conventional fashion. For example, the machine operating control means and logic circuitry 122 can contain a conventional means for timing the interval of operation of the first and second modes of machine operation. These types of controls of machine operation are well known in the art, and are not further described here. Conventionally, the control means and anti-tiedown logic circuit 122 prevents the continued actuation of one mode or another when the beam of one of the switches 11 and 12 is continuously obstructed, or if the length of time between operation of them is unacceptably long, thus preventing the possibility of bypassing the safety feature of the invention produced by the spacing of the pair of switches 11 and 12. Again, it is most preferred that such circuitry is incorporated in the existing machine whose switches are replaced with those of the present invention. Such safety circuitry is, by itself, not part of the invention, but rather is part of the prior art.

The present invention thus provides a switch apparatus which is substantially more mechanically reliable than are prior art switch apparatus, and which avoids the Carpal Tunnel Syndrome encountered in the repetitive use of conventional machine operating switches such as palm buttons. Advantageously, the switch apparatus of the present invention is useful in conjunction with a parallel pair of machine operating circuits; indeed, preferably, the switches of the present invention are directly connectable to the machine 10 in replacement of the existing palm buttons or other machine switches. In such a case, the first control circuits 38 and 40 of each switch are directly connected to the associated circuit limbs 116 and 120 of the machine from which the existing palm buttons or other switches have been physically detached. Of course, it should be clear that the particular structure of the switches 11 and 12 is a matter of choise choice, depending upon the environment in which they are to be used. For example, although a relay 24 has been used in the illustrated embodiment of the invention, it should be apparent that there are modifications of the present invention where such a relay would not be necessary.

Having described our invention, however, many modifications thereto will become apparent to those skilled in the art to which it pertains, without deviation from the spirit of the invention, as defined by the scope of the appended claims.

Claims

1. For use in conjunction with a machine having a mode of operation in which the machine is actuated to perform a machining operation and a circuit responsive to two input signals, said circuit preventing operation of said machine in said mode unless said circuit receives said input signals substantially simultaneously,

a pair of switch assemblies for producing said input signals, each switch assembly comprising:

a housing having a generally u-shaped opening having sides and a bottom, said opening being dimensioned to allow the introduction of a human hand into said opening between said sides and to said bottom,

a photo optical switch contained in said housing, said photo optical switch producing an output signal upon the introduction of a human hand into the opening and without contact between the human hand and the photo optical switch and without the necessity of the hand applying an exertive force,

means for electrically connecting the output signal from each photo optical switch as an input signal to said circuit to enable operation of said machine in said mode.

2. The invention according to claim 1, wherein said photo-optical switches comprise proximity switches.

3. The invention according to claim 1, wherein said photo-optical switches each comprise an infrared emitter and an infrared receiver spaced from said emitter.

4. The invention according to claim 1, and comprising an anti-tiedown logic circuit to which each of said photo-optical switches are operatively connected.

5. The invention according to claim 1, and comprising an actuation circuit having parallel limbs, each of said limbs being associated with disparate operative modes of said apparatus, and wherein said photo-optical switches each comprise an at least single pole, double throw, break-make solenoid actuated relay, operatively connected to said limbs, and means for energizing said relay.

6. For use in conjunction with a machine having a mode of operation and a circuit responsive to two input signals, said circuit preventing said mode of operation unless said circuit receives said input signals substantially simultaneously,

a pair of switch assemblies for producing said input signals, each switch assembly comprising:

a housing having a generally u-shaped opening defined by a pair of substantially vertical side members with opposed facing surfaces extending upwardly from a bottom surface, said opening being of sufficient size to allow the introduction of at least a portion of a human hand thereinto;

a photo-optical switch contained in said housing, said switch including a light emitter supported immediately adjacent one of said side surfaces and a light detector supported immediately adjacent the other of said side surfaces, such that the light from said emitter travels directly to said detector along a straight path defining a beam,

said photo-optical switch producing an output signal upon the interruption of said beam through the introduction of a human hand into the opening of said housing without contact between said hand and the bottom of said housing, and without the necessity of said hand applying an exertive force; and

means for electrically connecting the output signal from said photo-optical switch as an input signal to said circuit to enable operation of said machine in said operational mode.

7. The invention according to claim 6, wherein said beam is substantially horizontal.

8. The invention according to claim 6, wherein said beam is infrared.

9. The invention according to claim 6, further including an anti-tiedown logic circuit operatively connected to each of said photo-optical switches.

10. The invention according to claim 6, further including:

an actuation circuit having parallel limbs, each of said limbs being associated with a disparate operational mode of said machine; and

a double-throw relay operatively interconnecting said photo-optical switches to said limbs.

11. The invention according to claim 6, wherein said switch assemblies are sufficiently spaced apart so as to obviate simultaneous operation by a single hand of an operator.

12. For use in conjunction with a machine having first and second disparate modes of operation and a circuit responsive to two input signals, said circuit preventing one of said modes of operation unless said circuit receives said input signals substantially simultaneously;

a pair of switch assemblies for producing said input signals, each switch assembly comprising a housing having a generally u-shaped opening defined by a pair of substantially vertical side members with opposed facing surfaces extending upwardly from a bottom surface, said opening being of sufficient size to allow the introduction of a portion of a human hand thereinto, and a photo-optical switch contained in said housing, said switch including a light emitter and a light detector supported on either side of said opening so as to establish a light beam thereacross;

said photo-optical switch producing an output signal upon the interruption of said beam without contact between said hand portion and the bottom of said housing, and without the necessity of said hand portion applying an exertive force;

an actuation circuit having parallel limbs, each of said limbs being associated with one of said disparate operational modes of said machine; and

a double-throw relay operatively interconnecting said photo-optical switches to said limbs to enable operation of said machine in only one of said operational modes at any given time.

13. The invention according to claim 12, wherein said beam is substantially horizontal.

14. The invention according to claim 12, wherein said beam is infrared.

15. The invention according to claim 12, further including anti-tiedown circuitry characterized in that one throw of said relay is operatively connected to said anti-tiedown circuitry for each mode of machine operation.

16. For use in conjunction with a machine having a mode of operation and a circuit responsive to two input signals, said circuit preventing said mode of operation unless said circuit receives said input signals substantially simultaneously when an operator exerts force onto a pair of manually operable switches, a method of updating the control of said machine, comprising the steps of:

removing said manually operable switches while leaving said circuit intact;

providing a pair of housings, each having a generally u-shaped opening defined by a pair of substantially vertical side members with opposed facing surfaces extending upwardly from a bottom surface, each opening being of sufficient size to allow the introduction of at least a portion of a human hand thereinto, and an optical switch assembly disposed in each opening for producing said input signals; and

connecting said optical switch assemblies to said circuit.