US2433180A - Limit switch actuator - Google Patents

Description

Dec. 23, 1947 E. 6. WHITE LIMIT SWITCH ACTUATOR Filed June 14, 1943 .12 f Ezrlu/bi INVENTOR. 14 '2 BY fiaawmy' 116 4 Mme Patented Dec. 23, 1947 UNITED STATES PATENT O F FIC E SWITCH ACTUATOR Earl White, Hobart, Ind.

Application June 14., 1943.. Serial No. 490.727

3 Clai'ms; I

My invention relates to improvements in limit switch actuator and more especially includes the features pointed out in the annexed claims.

The purpose of my invention is to provide a safety feature to be attached to an overhead crane or on a locomotive crane to release an alarm in the operators cabin whenever the crane reaches a predetermined point of danger that the alarm is operated during the forward or rear movement of the crane; that it is automatically inoperative when the crane moves away from the danger zone. However, the alarm is eiiective within short lengths of travel or longer distances determined by any desired limit means placed in the path of travel. The device is simple in its construction and it is elfective under changing circumstances.

With these and other ends in View I illustrate on the accompanying drawing such instances of adaptation as will show the broad features of the invention without limiting myself to the specific details shown thereon and described herein.

Figure l is a top plan.

Figure 2 is a side elevation.

Figure 3 is a diagrammatic View of the restoring mechanism.

Figure 4 is a diagrammatic View of the circuit closing features associated with a control switch.

Figure 5 is a detached diagram of a non-pivoted switch.

Figure 6 is a detached detail of an elastic connection between the switch and the pilot limiting arm.

Figure 7 is an enlarged plan in section of a pair of interrolling guide wheels.

Figure 8 is an elevation of Fig. 7.

Figure 9 is an elevation in section of a pair of interacting grooved idling rollers.

Figure 10 is a diagram of a simple alarm circuit.

In practicing my invention I do not limit myself to the specific details of mechanism of construction and operation that the varying exigencies of operation may demand without depart ing from the broad concept of the invention,

My safety alarm is positioned in an attachable and detachable manner on an overhead traveling or a locomotive surface traveling crane, at one or more positions on the crane, in such a relation that a pilot lever will operate an alarm signal in the operators cabin. The pilot lever may be p0 sitioned at any desired place on the crane and the trip may be attached to the frame work of the overhead track for the crane, or it may be placed alon side of the path of travel at any desired point.

The movement limiting feature may be a stake in the ground in the path of travel of a surface locomotive crane. These limits are adjustable, that is they may be placed anywhere in advance of a danger zone and they are so positioned that as the crane travels on its tracks the pilot arm will engage the stop before the danger zone is reached. The stop may be any desired stake or arm placed in changeable positions in the path of the moving crane.

In its simplest form my alarm is mounted on a base I that is permanently attached to or clamped to the frame of a crane in an desired manner. It. may be located at different points on the crane, in duplication or otherwise so that the safety factor of my device will come into play, in either direction of the movement of the crane.

The base I is attached to any desired part of a crane so that its pilot arm or trip lever 2 will project forward of the base in any desired direction so that the arm 2 will engage a trip 3 placed at any desired point in the path of travel of the crane on the track frame or on the ground.

The front end of the pilot or trip arm 2 is formed of two reverse curves 4. This is so shaped that its range of action is increased over that secured by a simple straight sided trip arm. It is pivoted to the base plate at 5. Its short end 6 is attached to a restoring cable I. This cable passes through between the adjacent grooves 8 of a pair of idler pulleys 9. It then passes rearward and is attached to a restoring spring Ill. The pivot 5 is in line with the spring Ill and the grooved opening 8 between the two idlers 9.

When the short end 6 of the arm 2 moves to either side of its center it is against the tension of the spring In which restores the pilot arm 2 to its central position regardless of the direction that the arm is moved around its pivot 5. This always returns the pilot arm to its neutral position.

At the same time that the arm 2 moves around its pivot 5, in either direction a plate ll attached to it above the pivot moves with it. This plate is connected to an ordinary switch 12 by means of a conventional "bead chain l3. This chain is attached to a spring M which in turn is connected to two pins l 5 on the plate I l by means of a separate chain Hi. When the arm 2 is in neutral position the chain l6 forms a triangle which includes the two interconnected pins IS. A link I! may be placed, above the chain it and on the pins I5. It prevents the chain l6 becoming tangled with one of the pins when the arm 2 is moved into an extreme position.

The switch I2 is supported in a frame l8 that may be pivoted at l9 to conform to the move- 3 ment of the arm 2 as it is shifted to the right or the left. A rod 20' attached to the frame l8 and the spring I 4 serves to hold the bead chain l3 in alignment with the spring 14, chain l6 and one pin l5.

The rollers 9 are mounted on a base 2| and they turn on pivot pins 22. One of the rollers 9 has a larger diameter circumferential tongue 23 on each side of the groove 8 and the companion roller has a groove 24 in which the tongue 23 freely enters. This construction serves to hold the cable 1 in the roller groove 8 against accidental displacement. A yoke 25 may be placed above the rollers 9. It assists in holding the pins 22 in spaced-apart relation.

I do not limit myself to the arrangement of parts shown on Fig. 4 as the switch frame 26 may be secured to the base I in any desired manner as shown in Fig. 5. The bell end 21 is adapted to a free movement of the head chain 13 as is usual in conventional practice.

What I claim is:

l. A pilot arm of a traversing circuit closer which comprises an attachable and detachable base, a pilot arm pivoted on the base for movement said arm extending from the pivot to engage a safety trip external of the base and in the path of said traverse, a short extension from the arm on the opposite side of the pivot, a cable, a spring having one end of it secured to the base and the other end attached to the cable and the cable in turn attached to the short end of the pilot arm, a pair of grooved rollers one on each side of the cable positioned so that the cable passes freely between the adjacent grooves and serves to hold the pilot arm in a neutral position.

2. A relatively long pilot arm adapted to engage a safety stop which comprises opposite curved edges, a pivot for the arm, a short extension to one side of the pivot, a cable attached thereto, a spring attached to the cable, a base to which the spring is attached and on which the arm is pivoted, and a pair of rollers having inter engaging grooves between which the cable passes, said adjacent grooves, the spring and the arm pivot being on approximately the same vertical plane.

3. A traversing circuit closer comprising a relatively long arm, a pivot therefor, a short extension to one side of the pivot, a lateral extension above the short extension, an elastic connection from the lateral extension to a circuit closer, an elastic connection from the short extension, a base for the parts, means for automatically holding the arm in a neutral position, and means for operating the circuit closer when the arm is moved a predetermined distance to either side of its neutral position by a trip in the path said arm traverses,

EARL G, WHITE.

REFERENCES CETED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,426,193 Holmgren Aug. 12, 1922 1,483,173 Gordon Feb. 12, 1924 1,671,615 Spahr May 29, 1928 1,902,700 Hadano Mar. 21, 1933

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