Abstract:
This safety monitoring system for punch press operators is designed to prevent the operators from being injured by such presses or other factory equipment. Primarily, it consists of a pair of wrist units which are strapped to the wrists of the operators, and which include optical fiber cables and a latching assembly, and the optical fiber cables are used in cooperation with a pair of identical electronic circuits employing LED&#39;s, a light sensitive transistor, a pair of other transistors, a zener diode, and a relay, for instantly shutting a punch press on or off.

Description:
This invention relates to machine safety devices, and more particularly, to a safety monitoring system for punch press operators. 
     The principal object of this invention is to provide a safety monitoring system for punch press operators, which will be so designed, as to prevent a punch press operator from getting the hands or fingers injured in the pinch areas of punch presses. 
     Another object of this invention is to provide a safety monitoring system for punch press operators, which will be unique, in that it will be an improvement over the prior art. Presently, pull back systems are only effective when they are being worn, and the punch press may be operated whether the pull back system is being worn or not. The present invention prevents the machine from operating unless the wrist units thereof are buckled, and properly in place. 
     A further object of this invention is to provide a safety monitoring system for punch press operators, which will include monitoring circuits, which, when the wrist units are properly mounted on the operator&#39;s wrist, are completed, thus enabling the machine to operate. 
     A still further object of this invention is to provide a safety monitoring system for punch press operators, which will have fail-safe means, will have no electrical voltages at the operator&#39;s wrists, the optical cable thereof cannot be shorted, jumped, or spliced together, and, if the cable fails, it cannot be twisted or spliced together. Even further, it will be light in weight, will not impede the operator, or add to job complexity, and there will be no reduction or loss of production time when operating the punch press. 
     Other objects are to provide a safety monitoring system for punch press operators, which is simple in design, inexpensive to manufacture, rugged in construction, easy to use, and efficient in operation. 
     These, and other objects, will be readily evident, upon a study of the following specification, and the accompanying drawing. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a block diagram of the present invention; 
     FIG. 2 is a plan view of one of the wrists units of the invention; 
     FIG. 3 is a view taken along the line 3--3 of FIG. 4; 
     FIG. 4 is a fragmentary cross-sectional view of the optic cable structure of the invention; 
     FIG. 5 is a top plan view of the circuit package of the invention; 
     FIG. 6 is a schematic wiring diagram of the circuit of the present invention; 
     FIG. 7 is a bottom plan view of the housing mechanism of the invention; 
     FIG. 8 is a side elevational view of FIG. 7; 
     FIG. 9 is a view taken along the line 9--9 of FIG. 8, and is illustrated rotated ninety degrees clockwise; 
     FIG. 10 is a cross-sectional view, taken along the line 10--10 of FIG. 9, and illustrates the latch and buckle tongue in the locked condition, and 
     FIG. 11 is a cross-sectional view similar to FIG. 10, but illustrating the latch and buckle tongue in unlocked condition. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Accordingly, a system 10 is shown to include a wrist unit 11 for attachment to the operator&#39;s hand, an electronic package or unit 12 having circuit 14 therein, which is coupled to wrist unit 11, and the machine control equipment 14a, which is coupled to the punch press 15 or other factory machine. Two of the wrist units 11 are required, one for each hand 13 of the press 15 operator, and one electronic package or unit 12 is required for each wrist unit 11. Each unit 11 includes a housing 16, having a rectangular eye 17, suitably fixedly secured to one side, and a buckle 18 is similarly secured to the opposite side, for removably and adjustably receiving a web strap 19, having openings 20 therethrough, for its adjustment. A second strap 21 is provided, and is fixedly secured, at one end, to strap 19 in a suitable manner, and its opposite end is suitably fixedly secured to ring 24, and ring 22, for a person&#39;s pull-cable 22a, is received within openings 23 of housing 16, by means of bar 24a. Strap 21 is received between the thumb and forefinger of the operator&#39;s hand 13, and strap 19 is fastened around the wrist of the operator for proper operation of system 10. The buckle tongue 18a is one of the key factors in the operation of system 10, which hereinafter will be described. The base 25 of unit 11 includes a cover 26, which is suitably fixedly secured to base 25. Optical fiber cables 27 and 27c are bonded to the interior of unit 11 in a suitable manner, and are separated by gap 27d, and Buckle tongue 18a is pivotally received upon a shaft or pin 28, which is fixedly secured across opening 29 in base 25, and the projection 30, which is integrally attached to tongue 18a, provides for engagement with one side of an &#34;E&#34;-shaped wire spring 31 within recess 32. One end of spring 31 is rounded, and is received within cut-out 33 of a projection 34, jutting inward of one side of base 25, and is integrally attached thereto, for retaining spring 31. Looking now particularly at FIG. 10 of the drawings, there is illustrated the locked condition of unit 11, by the wrist strap 19 being engaged with the buckle 18 and the buckle tongue 18a. In this instance, one leg of spring 31 engages in the lower cut-out notch 35 in one edge of the latch 36. Latch 36 is freely and slideably received within opening 37 through base 25 and cover 26. Latch 36 is provided with a circular base (a pressure plate) 38 which is integrally attached thereto, and serve to engage with one end of a pair of coil springs 39 received within openings 40 in base 25. A rubber diaphragm 41 includes an integrally attached annular projection 42, which is frictionally received within a similar-shaped cut-out 43a in base 25, and diaphragm 41 engages with latch 36 at its bottom end, and the opposite ends of springs 39 engage with the bottoms of openings 40, so as to urge latch 36 to its normal upward position. An aperture 43 is provided through latch 36, and with aperture 43 in the position shown in FIG. 10, light can be transmitted therethrough, by means of the optic fiber cables 27 and 27c. Semicircular grooves 44 in base 25 and insert serve as recess means for receiving cables 27 and 27c. The ends of cables 27 and 27c are secured within threaded couplings 27a, and by screw fasteners 27b. 
     The circuit 14 includes a light emitting diode 45, the light of which is directed upon the optic fiber cable 27, and this light produced is transmitted, via cable 27, to the aperture 43. LED 45 is coupled across wires 46 and 47, which are connected to a twelve volt power supply (not shown). A pair of resistors 48 and 49 are coupled across wires 46 and 47, and are in series with LED 45, and a zener diode 49 is coupled across LED 45 and resistor 49, for limiting current flow. A light sensitive transistor 50 is also coupled across wires 46 and 47 by its collector 51 and its emitter 52, the emitter 52 being coupled to the negative side of the power supply, and the collector 51 being coupled in series with resistors 53 and 54. The base 55 of a second transistor 56 is coupled between resistors 53 and 54, and the emitter 57 is coupled to the positive wire 46 of circuit 14. The collector 58 of 56 is coupled in series with resistors 59 and 60, which are coupled to the negative or ground wire 47, and the base 61, of a third transistor 62, is coupled between resistors 59 and 60. The collector 63 of 62 is coupled with a resistor 64 to the base 55 of transistor 56, and the negative side of a relay 65 is coupled between resistor 64 and collector 63 of 62, the emitter 66 of transistor 62 being coupled to the negative or wire 47 of circuit 14. The contacts 67 of relay 65 are coupled in series with the control circuit or circuits of the machinery, which are not shown. 
     In operation, each wrist unit 11 is placed on the operator&#39;s hands by the fingers being inserted within the confines of the straps 21, and strap 19 is then passed through buckles 18 thereof, and fastened by means of buckle tongues 18a and openings 20. When properly mounted on the wrists, the monitoring circuits 14 are completed, thus enabling the punch press 15 or other equipment to operate. The abovementioned is accomplished by moving the latch 36 of each unit 11, by wrist pressure, from an unlatched condition to a latched condition, which is when the wrist strap 19 is captured, and holding the buckle tongue 18a against the buckle 18, which moves the latch spring 31 to lock the latch 36 in position in the lower notch 35. With the latch 36 in the abovementioned position, light from LED 45 is transmitted through aperture 43 by cable 27 means. This transmission energizes the circuits 14, and permits the press 15 to operate. 
     Two motions are required to set system 10. The first is the moving up of latch 36, and the second is permitting the buckle tongue 18a to move the latch spring 31 into an extended and latch locked condition, and should the buckle 18 be released, the latch spring 31 will automatically release the latch 36 to its normal position, and the mechanical operation of attaching the wrist units 11 sets up the operation of the electronic and electrical system, plus the optical components. 
     With the twelve volt power supplied to the circuits 14, the LED 45 of each directs light upon the optical cable 27, and this light by cable 27 is transmitted to the aperture 43. With the latch 36 in the elevated position, the light will pass to the other portion of the optic cable 27, and will be conducted to the light sensitive transistor 50. Transistor 50 causes transistor 62 to function, which causes relay 65 to be actuated, which causes the press 15 or other equipment to operate, and any event which interrupts the light source, or blocks the light source, will cause the press 15 or other equipment to stop operating, and it shall be noted, that all of the light is contained within the optic cables 27, or the attaching hardware. 
     While various changes may be made in the detail construction, it is understood that such changes will be within the spirit and scope of the present invention, as is defined by the appended claims.