US2843707A - Electrical safety switch - Google Patents

Description

, Filed May 3, 1955 y 1958 J. BEREZANSKY ETAL 2,843,707

ELECTRICAL SAFETY SWITCH 2 Sheets-Sheet 1 INVENTORS,

9 Jb/m fierezonsky,

George Gdow'c/u'n ATTORNEY y 1953 J. BEREZANSKY ETAL 2,843,707

ELECTRICAL SAFETY SWITCH 2 Sheets-Sheet 2 Filed May 5, 1955 BY f m 8 ATTORNEY 6 mm rww 6 ELECTRECAL SAFETY SWITCH John Berezansky, Mineral Point, and George Gdovichin,

Ehensburg, Pa, assignors to .lab Company, Inc, Ebeneburg, Pa, in corporation of Pennsylvania Application May 3, 1955, Serial No. 505,803

2 tllalms. ill. 260-4156) stopping of the belt or lift at various positions along the 1 belt or lift, as well as at the receiving and discharging end. The accepted method of operating the controls for the driving means for the belt or lift is by way of a cord suspended parallel to the belt or lift, and positioned within easy reach of the operators and users of the con veyor, the cord being attached to the controlling means. It is, therefore, the prime object of our invention to provide a posiitve and safe cord cooperated mechanism for manipulation of the power control for a belt driving means.

Another object of our invention is to devise a control operating mechanism that will function equally as well to manipulate electrical, mechanical, and fluid ru'essure controlling means.

Another object of our invention is to provide a control manipulating mechanism that has inherent safety features in that only one pull on the cord is required to manipulate the device to shut the power off or disconnect the driving means While two pulls on the cord is required to turn the power on or to connect the driving means.

Another object of our invention is to devise a control manipulating mechanism that is readily removable from the power controller for repair or for adjustment while the driving means is either shut down or supplying power to the conveyor.

Another object of our invention is to devise a control manipulating means provided with a safety latch that can be positioned to insure that the power controller is not turned on when it is desirable to have the lift or conveyor remain immobile. Another object of our invention is to provide a power control manipulating device that requires two pulls of the operating cord to start or connect the power source to the belt drive, thus insuring against inadvertent starting of the belt by accidental pull or force exerted on the operating cord.

Other objects, novel features, and advantages of arrangement, construction, and design comprehended by the invention are hereinafter more fully disclosed in the description of a preferred embodiment as illustrated in theaccompanying drawings, showing our improved device arranged to operate an electric switch. In the drawings, like characters denote corresponding parts throughout.

In the illustrations:

Fig. 1 is an isometric View of a switch box, having attached to the right side thereof, our improved control manipulating mechanism.

Fig. 2 is an isometric view showing the safety latch arranged to maintain the switch within the box in the open position.

Fig. 3 is an isometric view of the switch box alldflitached control manipulating mechanism with the covers removed.

Fig. 4 is a fragmental elevational view of the left hand side of the switch box showing the control safety latch in the engaged position.

Fig. 5 is a fragmental elevational view of the left hand side of the switch box showing the control safety latch in the disengaged position.

Fig. 6 is a fragmental elevational view of the control manipulating mechanism showing the mechanism securing the switch within the box in the open position.

Fig. 7 is a fragmental elevational view of the control manipulating mechanism showing the position of the mechanism after the operating cord has been pulled once and the mechanism still securing the switch within the box in the open position.

Fig. 8 is a fragmental elevational view of the control manipulating mechanism showing the position of the mechanism after the operating cord has been pulled twice and the mechanism has moved the switch within the box to the closed circuit position.

Fig. 9 is an elevational view of our improved control manipulating device.

Fig. 10 is a sectional elevational view of the control manipulating device taken along line ill-1i) of Fig. 9.

Fig. 11 is an isometric top view of the ratchet member of the control manipulating device.

Fig. 12 is an isometric bottom View of the ratchet member shown in Fig. 11.

Referring now in greater detail to the drawings, we disclose a control manipulating device, generally designated A, mounted on the side 20 of a switch box, generally designated as B, and arranged to open and close a switch, generally designated C, within the box B. In the illustrations shown and described hereinafter, the control manipulating device is presented as it would be when manipulating an electric switch. However, it is to be understood that the control manipulating device functions equally as well in controlling a fluid pressure valve and in engaging and disengaging a mechanical clutch, it only being necessary to provide the required linkage between the control manipulating device and power or force controlling means.

The control manipulating device is comprised of a base unit 21 having a circular portion 22 arranged to be inserted through and to interfit with a hole 23 in the side 2! of the switch box B. A flanged portion .24 on the base unit 21 is arranged to be secured to the side 20 of the switch box by the securing screws 25. A yoke portion 26 is held in definite space relationship to the base portion 21 by the legs 27-27 and is secured to the flange portion 24 by securing screws 28-4155 that pass through the flange 24 and into the legs 27 (see 9). Interfitting within a circular cavity 29 in the yoke portion 26 is a ratchet member 30 (see Figs. 11 and l2). The ratchet member 30 has ratchet teeth 31 on its periphery and ratchet teeth 32 on its inner surface. Extending outward from the outer surface 33 of the ratchet member ratchet wheel 39 is an operating pin 34. The functioning of the ratchet member 39 and operating pin 34 will be described hereinafter.

Positioned radially in a circular hole 36in the yoke portion Zta is a spring loaded ratchet pin or stop37, a helical compression spring 33 reacting between the base of the hole as and the end of the ratchet pin 37 tends to retain the inner end of the ratchet pin 37 in contact with the ratchet teeth 32 on the periphery of the ratchet member 30. The ratchet pin or stop 37 and the ratchet teeth 31 cooperate to permit clockwise rotation of the ratchet member 3t} and to prevent counterclockwise rotation of the ratchet member. The ratchet member 30 is retained within the circular cavity 29 in the yoke portion by an inwardly extending flange 39 on the yoke portion 26.

Positioned between the yoke portion 26 and base unit 21 of the control manipulating device A is an operating arm securing unit 40. Fixedly attached to and extending radially, 180 apart, from a flanged portion 41 of the operating arm securing unit 40, are cord securing operating arms 42-42. Operating cords 43-43 are secured to the outer ends of the operating arms 4242 by the cord securing loops 4444 and screws 45-4-5. An outwardly extending tubular shaft 46 on the operating arm securing unit 40 is arranged to interfit with and rotate in a bore 47 in the ratchet member 30. An inwardly extending tubular shaft 48 is arranged to interfit with and rotate in a bore 49 in the base unit 21. The tubular shafts 46 and 48 interfitting with the bores 47 and 49, respectively, rotatably position the operating arm securing unit 40 within the control manipulating device A. When the control cord A is pulled and released spring 56 moves the operating arms 42-42 to a position to be operated again. Positioned within a circular hole 50 in the outer surface of the flanged portion 40 of the operating arm securing unit A is a spring loaded ratchet pin 51 (see Fig. A helical compression spring 52 reacting between the base of the hole 50 and inner end of the ratchet pin or pawl 51 tends to retain the ratchet pin 50 in contact with the ratchet teeth 32 on the inner surface of the ratchet member 30. With the ratchet pin 51 in contact with the teeth 32 on the ratchet member 30, it can be readily seen that clockwise rotation of the operating arm securing unit 40 will cause the ratchet pin 51 to engage the teeth 32 and cause the ratchet member 30 to be rotated in a clockwise rotation.

Positioned on the inner end 53 of the control manipulating base unit 21 is a helical torsion spring retaining unit 54. The helical torsion spring retaining unit 54 is comprised of a flange member 55 which is arranged to secure the inner end of a helical torsion spring 56 by way of a torsion spring retaining pin 57; the torsion spring retaining pin being positioned and fixedly secured in radial holes 5858 in the flange member 55 (see Fig. 10). A tubular shaft 59, a part of the helical torsion spring retaining unit, interfits with the bore 49 in the base unit 21 and rotates therein. A set screw 60 threaded through the wall of the base unit circular portion 22 provides a means for definitely positioning the helical tension spring retaining unit 52 after the proper amount of torsion is placed on the torsion spring 56. The outer surface 61 of the flanged member 55 is knurled so that it can be rotated by the fingers or by a wrench, and when the desired torsion is established in the torsion spring 56, the helical tension spring retaining unit is definitely positioned by the set screw 60.

The helical torsion spring 56 is secured at its inner end by the pin 57 as described above (see Fig. 10), and is secured at its outer end by a second torsion spring retaining pin 62. The second retaining pin 62 is secured near the outer end of the tubular shaft 46 of the operating arm securing unit 40 and is positioned by radial holes 63-63. The torsional force set up in the helical torsion spring 56 by the adjustment of the helical torsion spring retaining unit 54, as described above, is a force that tends to rotate the operating arm securing unit 40 in a counterclockwise direction (see Fig. 9), and return the operating arm securing unit 40 to the position shown in Fig. 9 after it has been operated by the pull cords 4343.

The operation of the control manipulating device A is as follows: When tension is applied to either of the operating cords 43-43, the cords force the operating arm securing unit 40 to rotate in a clockwise direction (see Fig. 9). As the operating arm securing unit 46 rotates, the ratchet pin 51 engages the teeth 32 and causes the ratchet member 30 to also rotate in a clockwise direction.

After the ratchet member 30 has rotated in a clockwise direction 120, the ratchet pin 37 in the yoke portion 26 engages one of the ratchet teeth 31 on the periphery of the ratchet unit and prevents counter-clockwise rotation of the ratchet member 39 when the operating arm securing unit rotates counter-clockwise and returns to its origi nal position. It will be observed from the illustrations and the above description that each succeeding pull on the operating cords 43-43 causes 120 clockwise rotation of the ratchet meber 30.

The lever end dead-center-spring actuating mechanisms associated with the control manipulating device A are comprised of an actuating lever 64 pivotally attached to the side of the switch box 24 at 65. A slot 66 in the actuating lever 64 is arranged to be engaged by the operating pin 34 of the ratchet member 30. The lower end of the actuating lever 64 is pivotally attached to a deadcenter spring unit 67 at 63. A shaft 69 of the deadcenter spring unit 67 extends downward and passes through a hole 70 in an L-shaped connecting link 71. Below the L-shaped connecting link 71, the shaft 69 is surrounded by a helical compression spring 72 which is compressed and positioned on the shaft 69 between the L-shaped connecting link 71 and a nut 73 which is secured to the lower end of the shaft 69. The L-shaped connecting link 71 is pivotally attached at 74 to a switch operating lever 75; the switch operating lever 75 is fixedly attached at 76 to the end of the switch mechanism shaft 77.

The switch mechanism of the embodiment illustrated is comprised of a flat insulating plate 78 fixedly attached to the switch mechanism shaft by the screws 79. Adjustably mounted electrical contacts $tl80 are secured to the lower edge of the fiat insulating plate 78 and are connected by a flexible electrical connection 81. The electrical contacts 8tl-80 are positioned on the flat insulating plate so that when the switch is in the closed position (see Fig. 8), the electrical contacts will engage fixed electn'cal contacts 82 to complete an electrical circuit and energize a driving motor for the belt or lift being controlled.

Now the operation of our improved mechanism for the operation of control devices is as follows: With the unit at rest and the switch in the open position (see Fig. 6), the helical torsion spring 56 maintains the cord securing arms 4242 in contact with the spacer legs 27 and in a horizontal position as shown in Fig. 9 and the ratchet member 30 is positioned so that the operating pin 34 is positioned at the lower end of the slot 66 in the actuating lever 64. With the operating pin 34 so positioned in the slot 66, the actuating lever positions the dead-center spring unit 67 so that the force exerted by the helical compression spring 72 on the L-shaped connecting link 71 tends to rotate the switch mechanism shaft 77 in a clockwise direction (see Fig. 6), and hold the switch in the open position. The first pull on either of the operating cords 43 rotates the operating arm securing unit 40 in a clockwise direction, rotating the ratchet member 30 also in a clockwise direction, as described in the foregoing. This clockwise rotation of the operating arm securing unit 40 and ratchet member 39 causes the operating pin 34 to move upward in the slot 66 to a position as illustrated in Fig. 7. When the cord is released, the operating arm securing unit 40 rotates, by reason of the torsion force in the helical torsion spring 56, in a counter-clockwise direction until the cord securing operating arms again impinge on the legs 27 ,of the yoke portion 26 (see Pig. 7). However, the ratchet unit 30 remains fixed due to the engagement of the teeth 32 on its inner surface with the ratchet pin 51 in the yoke portion 26 of the base unit 21 (see Fig. .10). A second pull on either operating cord again causes clockwise rotation of the operating arm securing unit 40 and ratchet unit 30, as described above, and the operating pin 34 moves to the position shown in Fig. 8. When the opcrating pin 34 moves from the position shown in Fig. 7 to the position shown in Fig. 8, it causes counter-clockwise movement of the actuating lever 64 on the pivot 65 and the pin becomes engaged by the holding notch 66A in the slot 66 of the actuating lever 64. As the actuating lever moves from the position shown in Fig. 7 to the position shown in Fig. 8, the pivotal connection 68 between the actuating lever 64 and the dead-center spring unit 67 moves from a position to the left of the switch mechanism shaft 77 to a position to the right of the switch mechanism shaft. As the pivotal connection 68 moves, as described above, the force exerted by the helical compression spring changes from a force tending to rotate the switch mechanism shaft 77 in a clockwise direction, as described above, to a force that tends to rotate the switch mechanism shaft 77 in a counter-clockwise direction, closing the switch mechanism (see Fig. 8). A third pull on either operating cord 43 again causes clockwise rotation of the operating arm securing unit 40 and ratchet unit 30, as described above, and the operating pin 34 moves to the position shown in Fig. 6. When the operating pin 34 moves from the position shown in Fig. 8 to the position shown in Fig. 6, it causes clockwise movement of the actuating lever 64 on the pivot 65. As the actuating lever moves from the position shown in Fig. 8 to the position shown in Fig. 6, the pivotal connection 68 between the actuating lever 64 and the dead-center spring unit 67 moves from a position to the right of the switch mechanism shaft 77 to a position to the left of the switch mechanism shaft. As the pivotal connection 68 moves, as described above, the force exerted by the helical compression spring changes from a force tending to rotate the switch mechanism shaft 77 in a counter-clockwise direction to a force that tends to rotate the switch mechanism shaft 77 in a clockwise direction, opening the switch, and holding the switch operating lever against the top pin 83 (see Fig. 6), thus completng one cycle of operation.

From the above description of operation, it will readily be observed that two pulls on the operating cord are necessary to close the switch, while only one pull is required to open the switch. This is an outstanding feature of our disclosure and one that adds greatly to the safe operation of conveyors and lifts when the drive means for the conveyors or lifts are controlled by our improved control device.

An added safety feature is also incorporated in our control operating mechanism in the form of a safety-lockout link (see Figs. 2, 4, and 5). Fixedly attached at 84 to the switch mechanism shaft 77 on the end that extends through the side 20A of the switch box B is a safety lever 85. The lower end 86 is turned outward and is arranged to be engaged by a safety link 87. The safety link 87 is pivotally attached to the side 20A of the switch box B at 88. Under normal operating conditions, the safety link 87 is disengaged from the safety lever 85, and the links hang vertically (see Fig. 5). However, should it become necessary to shut the belt down for repair, it is only necessary for the operator to rotate the safety link 87 on the pivot 88 and arrange the safety link 87 to engage the lower end 86 of the safety lever (see Fig. 5). With the safety lever 85 so secured, the switch C within the switch box B remains in the open position regardless of the number of times the cords 43 are pulled.

Although our invention has been described in considerable detail, such description is intended as being illustrative rather than limiting, since the invention may be variously embodied, and the scope of the invention is to be determined as claimed.

We claim as our invention:

1. In a mechanism for operation of a power control device wherein a plurality of pulls results in the operation of the control device and a single pull results in the nonoperation of the control device comprising a ratchet pawl, a rotatable ratchet wheel having three ratchet teeth therefor and being actuated by movement of said ratchet pawl, a dead center spring pressed lever having an elongated slot therein, a pin on said ratchet wheel and being slidable within said slot of said lever, and one end of said lever being pivotally mounted whereby said pin on said ratchet wheel must be moved an arcuate distance of two ratchet teeth to actuate said dead center spring pressed lever, and said lever having a notch adjacent said slot whereby said ratchet wheel pin will be held prior to the ratchet wheels movement back past dead center to open said control device.

2. The invention of claim 1 wherein an oscillating member carries said ratchet pawl and a spring attached to said oscillating member to turn it in one direction.

References Cited in the file of this patent UNITED STATES PATENTS 445,957 Lean Feb. 3, 1891 692,783 Dyre Feb. 4, 1902 825,084 Sorensen July 3, 1906 1,101,064 Dana June 23, 1914 1,147,949 Keen July 27, 1915 1,434,972 Tizley Nov. 7, 1922 1,587,837 Hopkins June 8, 1926 1,789,617 Brennan Jan. 20, 1931 1,803,163 Beebe Apr. 28, 1931 1,838,983 Angell Dec. 29, 1931 FOREIGN PATENTS 611,193 Germany Mar. 23, 1935 662,399 Germany July 12, 1938

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