US1946920A - Means for controlling the slack of cables - Google Patents

Description

Feb. 13, 1934. F. E. sTAHL MEANS OR CONTROLLING THE SLACK OF CABLES Filed June 23, 1935 J'vvEA/Tofl FRANK E STAHL Patented Feb. 13, 1934 Ares PATENT OFFICE MEANS FOR CONTROLLING THE CABLES SLAQK OF Application June 23, 1933. Serial No. 677,298

5 Ciaims.

My invention relates in general to means for controlling the slack of cables, and particularly to the control of slack in the cable of a handoperated hoist.

It is well known to those skilled in the art that in hand-operated hoists of the wire rope or cable drum type there isa tendency for the operator to continue to revolve the drum in the lowering position after the load has been relieved from the cable, thus causing the loose cable to be unwound from the drum with the result that such loose cable -is likely to become kinked or become entangled with the load being handled, thus causing damage to the cable or to the load or the surface and finish thereof, particularly if the load be an automobile in transit.

Attempts have heretofore been made to stop the rotation of a cable carrying drum when slack occurred in the cable. Such devices, however, have been in the nature of ratchet means applied to elevators and have'been used as safety locking devices. Were it attempted to use such ratchet means for hand-operated hoists, the stop produced by the ratchet means would be too abrupt and positive. Furthermore, should the operator continue to operate the hoist in a lowering direction, after the ratchet had once become engaged, the teeth might easily become broken off or the ratchet pawl become disen gaged. 9

It has, therefore, been an object of my invention to provide positive locking means for use in connection with hand-operated hoists which shall be gradual in its action.

Another object has been ,to provide locking means having a gripping action upon the drum and which will become more firmly engaged with the drum as the pull upon the hoist is increased.

Another object of my invention has been to provide means to positively stop the operation of the hoist (without the possibility of breaking the locking means) and to lock the same when the load is relieved therefrom and when fullness occurs in the cable.

Another object has been not only to operate a brake when fullness or slack in the cable does occur, but to provide means whereby the slack used for the operation of the brake or stop shall be taken up by the device, thereby always keeping the cable taut throughout its length.

Moreover, my device does not add materially to the cost of the hoisting mechanism and is very durable in its operation.

The above objects and advantages have been accomplished by the device shown in the accompanying drawing, of which:

Fig. 1 is a side, sectional elevation of my device.

Fig. 2 is a front elevation thereof.

. Fig. 3 is a diagrammatic view, showing the groove 7 formed in its periphery for the reception of the cable 8. Flanges 9 and 10 are formed on the drum. The flange 10 is provided in its periphery with a plurality of flutes 11 which are circularly shaped and of sufiicient size so as to give ample strength to the divisions between the flutes.

The shaft 6 is mounted in a suitable bearing bracket 15 provided with a bearing 16, a web 1'7, and a wall 18. A flange 19 is provided at the top of the bracket whereby it may be suitably secured in place.

A cam lever 25 having an inwardly extending arm 26 is pivotally attached to the web 17 preferably by means of a screw or bolt 27. The arm 26, of this cam lever is preferably passed through a slot 33 formed in the wall 18. The pivotal connection. of the cam lever is somewhat above the center line of the shaft 6 as hereinafter more specifically pointed out. As shown in Fig. 1, they cable 8 is extended from the drum in a horizontal direction and it passes over an idler sheave, as is customary (not shown), The

outer end 28 of the cam lever is made of such proportions that it will constitute a weight for the lever, and carried by this end of the lever is a U-bolt 29. This U-bolt passes around the horizontal pass of the cable 8 and the cam lever is supported by such engagement. The U-bolt is, as shown'in Fig. 2, secured in the end of the cam lever by any suitable means and extends across the drum so as to be in engagement with the cable throughout its travel across the drum.

A cam 30 is carried by the cam lever 25 and projects preferably from the face of the lever wh'iEh is adjacent the drum flange 10, whereby this cam will be opposite to and engageable with the flutes 11 of this flange of the drum. This cam is provided with a curve shaped surface 31 which'is preferably of substantially the same radius as the radii of the flutes 11.

The position of the cam 30 is such with relation to the flutes 11 that the cam will become lockingly engaged with one of the flutes of the flange before the flute so engaged reaches the horizontal center line of the shaft. This is better shown by the diagrammatic view of Fig. 3 where 35 represents the axis of the pivotal connection of the cam lever and 36 the axis of the drum. The cam 30 is shown engaged with one of the flutes 11 of the flange 10 of the drum, the position of the engaged flute being considerably above the center line 36. As shown in this diagrammatic figure, the direction of rotation or force applied to the drum in its lower direction is shown by the arrow 37, whereas the direction of movement of the cam 30 in its locking direction is shown by the arrow 38. It will be obvious that the weight of the cam lever not only serves to move it in the direction of the arrow, but that further rotation of the drum serves also to have a tendency to move the lever about its axis. As the curved surface 31 of the cam 30 and the flute 11 with which it has become engaged first contact, all such further rotative movement will tend to produce a force inwardly, as indicated by the arrow 39 and thus cause the cam to be firmly engaged with the flute by clamping action. This is brought about because of the fact that the pivotal point 35 of the lever as well as the point of contact of the cam with one of the flutes is above the center line 36 of the drum. By contrast, the teeth of the ratchet locking means of the prior art will under similar circumstances tend to become disengaged or broken off.

It will be obvious that as the tension on the cable is relieved when the load comes to rest, there is a tendency, upon continued operation of the hoisting mechanism, for fullness to occur in the cable. Such fullness is localized and is taken up by the weighted cam lever 25 which moves downwardly by gravity to the locking position shown by the dotted lines of Fig. 1, thereby keeping the cable taut at all times. Such movement will continue until the cam 30 engages with one of the flutes ll of the drum flange, after which the drum will be slowed up and stopped altogether when the cam has been firmly engaged with the flute. When the hoisting device is operated in the opposite direction, the fullness in the cable will be taken up as the cable moves to its normal horizontal position shown by the full lines of Fig. 1. During this movement the cam lever will be elevated and the cam will be disengaged from the flute of the flange 10 of the drum.

While I have shown my device as applicable to a cable extending horizontally, it is obvious that the device will work on a cable extending in a vertical plane, since the center line 35 of the bolt 2'7 is offset with respect to such a vertical pass of the cable, and the tendency of the weighted arm 28 of the cam lever 25 would be to rotate to the center of gravity. So as to a make the action more positive, the arm 28 may be made heavier or it may be provided with an outwardly extending weighted arm which will change the center of gravity of the lever to such an extent that the lever will be more positively operated.

These and other modifications of the details herein shown and described may be made without departing from the spirit of my invention or the scope of the appended claims, and 1' do not, therefore, wish to be limited to the exact embodiment herein shown and described, thc form shown being merely a preferred embodiment thereof.

Having thus described my invention, what 1 claim is:

1. The combination with a hoist drum and the cable thereof, of means for controlling the slack of such cable comprising a fluted flange carried by and rotatable with the drum, pivotally mounted cam means engageable with the flutes of the flange, and means carried by the cam means for engagement with the cable, whereby when fullness occurs in the cable, the cam will operate to lock the drum.

2. The combination with a hoist drum and the cable thereof, of means for controlling the slack of such cable comprising a fluted flange carried by and rotatable with the drum, a pivotally mounted cam lever, a cam carried by the lever and engageable with the flutes of the flange, the cam being located on the lever at one side of the flange and the pivotal point of the cam lever being located at the opposite side of the flange, and means carried by the lever for engagement with the cable, whereby when fullness occurs in the cable, the cam will operate to lock the drum.

3. The combination with a hoist drum and the cable thereof, of means for controlling the slack of such cable comprising a fluted flange carried by and rotatable with the drum, a pivotally mounted cam lever, a cam carried by the lever and engageable with the flutes of the flange, the cam being located on the lever at one side of the flange and the pivotal point of the cam lever being located at the opposite side of the flange, the point of engagement of the cam with the flutes of the flange and the axis of rotation of the cam lever being in a plane at one side of the axis of the flange, and means carried by the lever for engagement with the cable. whereby when fullness occurs in the cable, the cam will operate to lock the drum.

4. The combination with a hoist drum and the cable thereof, of means for controlling the slack of such cable comprising a fluted flange carried by and rotatable with the drum, a pivotally mounted, weighted cam lever, a cam carried by the lever and engageable with the flutes of the flange, the cam being located on the lever at one side of the flange and the pivotal point of the cam lever being located at the opposite side of the flange, and means carried by the lever for engagement with the cable, whereby when fulhiess occurs in the cable,.the cam will operate to lock the drum.

5. The combination with a hoist drum and the cable thereof, of means for controlling the slack of such cable comprising a fluted flange carried by and rotatable with the drum, a pivotally. mounted, weighted cam lever, a cam carried by the lever and engageable with the flutes of the flange, the cam being located on the lever at one side of the flange and the pivotal point of the cam lever being located at the opposite side of the flange, and a U-bolt carried at the outer end of the cam lever and engageable with the cable as it leaves the drum, whereby when fullness occurs in the cable, the cam will operate to lock the drum.

FRANK E. STAHL.

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