US3487280A - Hoist push button control - Google Patents

Description

Dec; 30, 1969 G. R. SANTOS 3,487,280

HOIST PUSH BUTTON CONTROL Filed March 17, 1967 I 2 Sheets-Sheet 2 INVENTOR. G. R. SANTOS ATTORNEYS United States Patent F 3,487,280 HOIST PUSH BUTTON CONTROL Gerard R. Santos, Levittown, Pa., assignor to Eaton Yale & Towne Inc., Cleveland, Ohio, a corporation of Ohio Filed Mar. 17, 1967, Ser. No. 623,915 Int. Cl. H02p 1/40, 1/00, 3/00 US. Cl. 318-267 Claims ABSTRACT OF THE DISCLOSURE My invention relates to motor operated hoists.

As may be appreciated, there is a considerable demand for motor operated hoists that an operator can control through the actuation of push buttons. There are in use many hoists that are controlled in that way, but due to the particular requirements of hoist operation, the push buttons often have made it necessary to equip the hoist with control mechanism that is quite complex and costly. In some cases, the controls do not offer the best performance. Through the novel concept of my invention, it will be possible to achieve extremely satisfactory operation of a hoist while utilizing push button control. Moreover, that can be done through means that are relatively low in cost and that actually are quite simple.

In my invention, I equip a hoist with a motor switch that may be of a usual type, together with a yielding connection through which control means will act to move the motor switch. The operator of the hoist will actuate the control means, as by push buttons, for controlling the lifting and lowering movements of the hoist. There are further means for moving the switch, and those means will be effective through yielding of the yielding connection to move the switch independently of the control means. More particularly, the further means will be limit means that move the switch to neutral position incidental to a limit operation of the hoist.

As a feature of my invention, I equip a hoist with a pair of solenoids that will move a switch from a neutral position to opposed positions for effecting lifting and lowering movements of the hoist. The solenoids are very well adapted to be controlled through push buttons and enable me to construct an effective hoist control requiring no complex circuits. As a more particular feature, I utilize a spring through which a solenoid normally will act to control the switch. The spring may yield when the switch is moved by hoist limit means, so that the limit means cannot overstress the solenoid when overriding the control that may be applied by the solenoid.

I have thus outlined rather broadly the more important features of my invention in order that the detailed description thereof that follows may be better understood, and in order that my contribution to the art may be better appreciated. There are, of course, additional features of my invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the concept upon which my disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of my invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope of my invention, in

3,487,280 Patented Dec. 30, 1969 order to prevent the appropriation of my invention by those skilled in the art.

In the drawings:

FIG. 1 shows a perspective view of a hoist that utilizes my invention.

FIG. 2 shows a diagrammatic view of my invention.

FIG. 3 shows a longitudinal section of the switch shaft and spring assembly.

FIG. 4 shows a cross-section on the line 4-4 in FIG. 3, the assembly being in neutral position.

FIG. 5 is a section like FIG. 4 but shows the assembly in normal lifting control position.

FIG. 6 is similar to FIG. 5 but illustrates the yielding of the spring when the limit control overrides normal lifting control.

FIG. 7 illustrates the yielding when the normal control is in lowering position.

Referring now more particularly to FIG. 1 of the drawings, I show my novel control 10 utilized on an electric hoist 11 having a frame 12 that is equipped with a support hook 13, and a motor 14 for operating a load chain 15. Those skilled in the art will understand that the motor 14 may operate in opposed directions to effect lifting and lowering movements of the load chain 15, there being suitable gearing (not shown) through which the motor acts. A limit member 16, a part of which can be seen in FIG. 1, will limit the operations of the hoist, and I shall refer in more detail to the limit member 16 as my description proceeds.

Referring again to FIG. 1, I mount on the hoist 11 a motor switch 17 having an operating shaft 18 that can rotate from a neutral position in either direction to energize the motor 14 in a corresponding direction. Preferably, the switch 17 is equipped with a centering spring 19, shown diagrammatically in FIGURE 2, applying pressure to a cam 19a on switch shaft 18 so as to press the switch shaft 18 toward neutral position. For purposes of disclosure FIGURE 2 also shows switch 17 equipped with a contact arm 17a that the shaft 18 will rotate from neutral position to engage either of two contacts 17b, so as to complete a corresponding directional circuit that will connect motor 14 through lines 14a to a source of power 14b. I believe that it will be unnecessary to describe motor switch 17 in further detail because that switch may be of a standard type. It is merely necessary here to know that the switch operating shaft 18 can be rotated to opposed positions effecting lifting and lowering movements of the load chain 15, the shaft 18 in neutral position stopping the operation of the chain. Merely to facilitate my description, I shall assume that switch shaft 18 is placed in lifting position when rotated counterclockwise, as viewed in FIG. 1.

In my novel control 10, I utilize a pair of solenoids 20, 21 mounted on the hoist frame 12, as through a bracket 22, that normally will control the rotation of the switch shaft 18. Power for the solenoids 20, 21 may be supplied through a transformer 60 that is connected to source 14]), FIGS. 1 and 2, and the operator of the hoist may energize the solenoids by depressing corresponding push buttons 61, 62. The armature 23 of each solenoid 20, 21 is connected to one end of a chain 24 that engages a sprocket 25, so that one solenoid when energized will rotate the sprocket in each direction. Solenoid 20 will effect counterclockwise rotation and therefore I may term it a lifting solenoid, and solenoid 21 a lowering solenoid.

The sprocket 25 is integrally secured to a sleeve portion 26 of a control part 27, best shown in FIG. 3, that is mounted to rotate relatively to the switch operating shaft 18. The control part 27 forms a portion of an assembly including a coil spring 28, and a mounting part 29 that is integrally secured to the end of switch shaft 18, as by a screw 30. I prefer to utilize a bushing 31 that keys a stem portion 32 of mounting part 29 to a portion 33 of switch shaft 18, those portions 32 and 33 being squared, as indicated in dotted lines in FIG. 4, to coact with a corresponding square opening in bushing 31. Control part 27 and its sprocket 25 then may rotate on the outer surface of bushing 31, with the friction preferably reduced through roller bearings 34.

Coacting with the coil spring 28, the control part 27 has inner and outer cylindrical walls 35 and 36, FIGS. 3 and 4, while mounting part 29 has cylindrical walls 37, 38 each arranged just inwardly of the corresponding Wall 35 or 36 on part 27. Between inner wall 35 on part 27 and outer wall 38 on part 29 is a circular space in which coil spring 28 is assembled.

As well shown in FIG. 4, the outer walls 36, 38 on control part 27 and mounting part 29 are formed with clearance openings 39, 40, one end of those openings forming stop surfaces 41, 42 for an angular end portion 43 on coil spring 28. Similarly, inner walls 35, 37 have clearance openings 44, 45 forming stop surfaces 46, 47 in opposed relation to surfaces 41, 42 and coacting with the inner spring end 48. Coil spring 28 is so tensioned that its end portions 43, 48 will act between the opposed stop surfaces 41, 42 and 46, 47, tending to prevent any relative rotation between the control part 27 and mounting part 29. At those times when the spring 28 yields, there naturally will be rotation in one direction or the other between the parts 27 and 29, while the spring ends 43, 48 move away from certain stop surfaces in the clearance openings, as may be seen in FIGS. 6 and 7. Actually, the coil spring 28 that I utilize in my invention will have strength sufiicient to hold parts 27, 29 in a predetermined relation to one another during normal operation of the hoist. Normally, therefore, parts 27 and 29 will rotate in unison, as from the FIG. 4 position to the FIG. position, so that the solenoids 20, 21 will fully control the rotation of the switch shaft 18.

I shall refer to FIG. 2 of the drawings while describing further means that will rotate switch shaft 18. Thus, I show diagrammatically at 50 in FIG. 2 a usual type of limit control including the limit member 16, to which I already have referred in connection with FIG. 1. The limit member 16 is arranged below a usual load wheel 51 through which the hoist motor operates the load chain 15, and is mounted at a medial point for tilting about a pivot 52 on the hoist frame. I show limit member 16 connected through link means 53 and a crank 54 to the switch operating shaft 18 so that limit member 16 by tilting may move the motor switch 17. The load portion 55 and slack portion 56 of the load chain extend from the load wheel 51 downwardly and when operating will move freely in openings in opposed portions of limit member 16. Load portion 55 of chain 15 is equipped with a load hook 57, while slack portion 56 is anchored at 58 to the hoist frame.

The limit arrangement that I have just described is not new, and those persons skilled in the art will understand that load chain 15 when moving to an upper limit position will cause the load hook 57 to engage the limit member 16 and to tilt it counterclockwise, as viewed in FIG. 2. When chain 15 moves to a lower limit position, its slack portion 56 Will engage a portion of limit member 16 so as to tilt it clockwise. That tilting of limit member 16 in either direction will move shaft 18 to neutral so as to stop the operation of motor 17 and chain 15. Should there be some overtravel of chain 15, that is, past a limit position, the tilting of member 16 will move switch shaft 18 past neutral so as to reverse the hoist motor, causing chain 15 to move back to limit position. That naturally will enable member 16 and shaft 18 to move again to neutral position.

I now call attention to the fact that the limit control 50 may operate through yielding of the coil spring 28, so as to rotate switch shaft 18 independently of the normal control that is applied through the solenoids 20,

21. Let us assume as an example that limit control 50 acts while solenoid 20 holds switch shaft 18 in lifting. position. In that position of shaft 18, control part 27 and mounting part 29 will be in the positions 27a, 29a, shown in FIG. 5, having been rotated from the neutral FIG. 4 position. Now, upon lifting limit operation of the limit control 50, the mounting part 29 will rotate with switch shaft 18 back to neutral position as shown in FIG. 6, while coil spring 28 yields so that control part 27 may remain in its position 27a. The lowering limit control operation will be substantially the same, though naturally being in directions opposed to those I have described, and with spring 28 yielding while control part 27 is held in position 27b as shown in FIG. 7.

I have already mentioned the fact that overtravel of the load chain 15 will cause switch shaft 18 to rotate past neutral, thereby reversing the hoist motor. When shaft 18 rotates in that way, the coil spring 28 can yield farther as I shall explain. Referring to FIGS. 5 and 6, it will be seen that the clearance openings 39, 40 and 44, 45 are considerably wider than is necessary to allow the spring ends 43, 48 to move When the limit control merely rotates mounting part 29 to neutral position. In the particular example shown, there merely need be a movement of approximately 45 between each spring end 43, 48 and its corresponding opening 39, 45. However, as also shown, each clearance opening actually allows approximately clearance. Thus, the spring ends 43, 48, can move farther, enabling coil spring 28 to yield while the limit control rotates mounting part 29 beyond its neutral position to a motor reversing position.

It will now be understood that my invention will enable the operator of a hoist to utilize push buttons so as to apply normal control to the movements of a hoist, while also enabling a limit control to act elfectively while overriding the push button control.

However, to fully appreciate my invention, it is necessary to realize that the limit control cannot overstress the normal control. That is important because the operator of a hoist frequently will attempt to hold the normal control in actuated position after the limit control op erates. In my invention, when that happens, the normal control may remain in actuated position and the limit control cannot force it toward neutral position. Thus, when the normal control comprises a solenoid, the operator cannot injure or destroy the solenoid through a continued application of power when the limit control operates.

Further, by utilizing solenoids I am able to control the movements of a hoist through means that are quite simple, while well adapted to be actuated through push buttons. Also, I achieve control that is extremely effective and that will very well meet the requirements of hoist operation. I believe, therefore, that the considerable value of my invention will be understood, and that its merits will be appreciated by those persons skilled in the art.

I now claim:

1. In a hoist having a load member and a motor for operating the load member, a switch for said motor, movable control means connected to the switch for moving said switch whereby to control the operation of the hoist load member by said motor, yielding means forming a connecting part between the control means and the motor switch and through which said control means normally act to control the movements of said switch to motor actuating and to neutral positions, limit means acting independently of said control means for moving the switch to a neutral position incidental to an operation of the load member, and said yielding means yieldmg so that said limit means cannot overstress the control means while moving the switch independently of said control means.

2. A construction as set forth in claim 1, including opposed stop surfaces against which said yielding means press on said switch and on said control means, and said yielding means having strength sufficient that its pressure against said surfaces normally will move the switch in unison with the control means.

3. A construction as set forth in claim l, in which said control means include a solenoid that acts through said yielding means, and means to energize said solenoid for moving said switch, and said yielding means having strength sufficient normally to move the switch in unison with the solenoid.

4. In a hoist having a load member and a motor for operating the load member, a switch movable to opposed positions actuating the motor to effect lifting and lowering movements of the load member, a pair of solenoids, means connecting each solenoid to said switch so as to be effective when energized to move the switch to one of said opposed positions, means for selectively energizing one solenoid or the other solenoid whereby to control the operation of the load member, further means positively connected to said switch and effective by moving the switch for positively overriding the control applied through the solenoids, and said means that connect each solenoid to the switch comprising a yielding portion that will yield so that said further means cannot overstress the solenoids when overriding the solenoid control.

5. A construction as set forth in claim 4, in which a spring forms said yielding portion of the connecting means, and including stop surfaces between which said spring acts relatively to the switch and solenoids whereby to press the switch toward a predetermined relation to the solenoids.

6. In a hoist having a load member and a motor for operating the load member, a switch having an operating member movable from a neutral position to opposed positions actuating the motor to effect lifting and lowering movements of the load member, a control part mounted for movement relatively to the switch operating member, means for moving said control part, a spring connecting the control part and the switch operating member and through Which said part may move said operating member to control the lifting and lowering movements of the hoist load member, limit means connected to the switch operating member and actuated by the load member positively to move said operating member to neutral position incidental to an operation of the load member, and said spring effective by yielding to enable the limit means to act independently of the movements of the control part.

7 A construction as set forth in claim 6, in which said spring has strength sufficient normally to hold the switch operating member in predetermined relation to said control part.

8. A construction as set forth in claim 6, in which said means for moving the control part comprise a pair of solenoids, and means for energizing said solenoids selectively to move the control part in opposed directions.

9. In a hoist having a load member operated through the actuation of a motor, and a switch equipped with a shaft that is rotatable from a neutral position in opposed directions to positions actuating the motor to effect lifting and lowering movements of the load member, a control part mounted for rotation on said switch shaft, a spring having opposed ends engaging the switch shaft and a control part and connecting said shaft and part for rotation normally with one another, a pair of solenoids connected to the control part for rotating said part in opposed directions, push buttons for energizing selectively one solenoid or the other solenoid whereby to control the rotation of the switch shaft, limit means connected to the switch shaft and effective to rotate said shaft independently of the control part to neutral position whereby to override the solenoid control incidental to a movement of the hoist load member to a limit position, and said spring yielding so that the limit means when overriding the solenoid control cannot overstress the solenoids.

10. A construction as set forth in claim 9, in which said spring is a coil spring mounted in the axis of the switch shaft, said shaft and said control part having stop surfaces between which the spring ends act to press said shaft toward a normal relation to said part, and said stop surfaces moving through yielding of said spring to enable said limit means to rotate the switch shaft in either direction from its normal relation to the control part.

References Cited UNITED STATES PATENTS 8/1941 Collins 318-466 1/1951 Townsley et al 318466 U.S. c1. X.R. 31 8446, 468

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