US2263482A - Automatic control for grabs, buckets, and the like - Google Patents

Description

1941. P. J-M. T. ALLARD BUCKETS, AND THE LIKE AUTOMATIC CONTROL FOR GRABS Filed Feb. 14, 1939 2 Sheets-Sheet l Nov. l8,-1941. P. J-M'. T. ALLARD AUTOMATIC CONTROL FOR GRABS. BUOKETS, AND THE LIKE 2 Sheets-Sheet 2 Filed Feb. 14, 1939 Jim E77 Patented Nov. 18, 1941 r F FlCE AUTOMATIC CONTROL FOR GRABS, BUCKETS, AND THE LIKE Pierre Jean-Marie Theodore Allard, Le Havre,

France, assignor to Societe Francaise de Construction 'de Bennes Automatiques, Graville-Le Havre, France, a French company Application February 14, 1939, Serial No. 256,390 In France September 10, 1938 4 Claims.

The present invention relates to an automatic controlling device for grabs or buckets of any type and especially for single rope grabs provided with an opening ring. It is a known fact that the grabs of this kind when they have to 'be opened are suspended from a ring secured to the lifting apparatus and that all operations are effected by means of a single cable or of a'single chain.

More particularly, the device according to the present invention may be used in combination with the plants described in applicant's older Patent No. 2,110,566.. These plants comprise a carriage which is adapted to carry the opening ring of the grab and to move on an inclined guiding track under the sole action of the weight of the grab and of its contents.

The device according to the present invention is chiefly characterized in that it comprises two transmission systems employing levers or like devices, one of these systems being actuated by the opening ring or like member when the grab is hooked thereto, and the other being acted upon by the lifting chain or cable when the grab is entirely open, these two sets of levers transmitting their action to a suitable mechanism acting upon the driving apparatus of the plant, and chiefly upon the direction of its motion.

'Other characteristics will be set forth in the following description.

In the accompanying drawings, given solely by way'of example:

' Figure l is an elevational view of an example in which the device according to the invention is used in the case of a plant having an inclined guiding track and a carriage carrying the opening ring; the shaft 2| being extended to show its connection with the reversing switch which latter together with the supply circuit and operating motor are also diagrammatically shown.

Figure 21 is a front view of the opening ring.

Figure '3 is a general view'of a plant according to the invention.

According to the represented embodiment, the plant comprises a guiding track I, upon which rolls a carriage 2 provided with rollers 3, and carrying an opening ring 5 of any suitable type secured by a chain 4, for instance. A pulley 6 is mounted at the top of the track I, and a second pulley l is mounted on the carriage 2. Cable or chain 8 for operating the grab is wound on a winch which is shown diagrammatically (Figure 1) at 9, and after passing over' the pulleys 6 *and 1 it is attached "to the top of the grab which is shown diagrammatically (Figure l) at It); As 'usual cable 8 traverses ring 5.

As it results from Figure 2, ring 5 carries a pivoted bar llr cooperating with a lever l2 provided with a counterweight I3 and pivotaliy mounted at its other end, at M, between lugs I 5 mounted on the lower part of guiding track I. The end of lever 12 carrying the counterweight is connected at I6 with a wire or chain ll passing over a pulley l8 and attached at I9 to a'bellcrank lever 20, for instance. This lever is pivoted on a shaft 2| pertaining to a suitable control mechanism, for instance to an electric reversing device shown diagrammatically in Fig. 1 as interposed in the supply circuit of the operating motor 45. The opposite arm of lever: 20 carries a counterweight 22. This counterweight is somewhat lighter than counterweight I3 and thus lever 20 is always urged by cable H in the direction of arrow f which brings it against a fixed stop 23. V

A second lever 24 is provided on the same shaft 2 l, and is secured thereto for positively operating the reversing switch. One end of this lever carries a counterweight 25 whereas its other end is connected at 26 with a cable or chain 21. The same end 26 of lever 24 carries a stop 28 adapted to cooperate with lever 20. The opposite end of cable 21 is attached at 29 to a bell-crank lever 30. This lever is pivoted at 3! to track I, and one of its arms is provided with a counterweight 32 whereas the other contains a pulley 33 acting upon cable 8. A stop 34 is provided at the lower end of track I. v

The operation of the device is as follows:

It is supposed that the plant is ready to lift the grab, which rests upon the goods. It should be noted that in the represented example, the movement of carriage 2 and of the grab which is attached to it takes place in the downward direction under the sole effect of their weight (movement from right to left on the drawings). Grab I0 after being filled is lifted by cable 8 and engages ring 5. The contact of the grab with the ring causes this latter to rise and to move bar I l and raise lever l2 in the direction of arrow f Cable ll being thus slackened is acted upon by counterweight 22 through the intermediary of lever 20, and the same lever also a'ctuates, by stop 28, lever 24. This latter being secured to shaft 2| causes operation of the reversing switch and the reversal of the movement of the lifting motor (position of the parts in dotand-dash lines). Carriage 2 travels on track I in the direction of arrow f and brings with it opening ring 5 of the grab l0. Lever l2 thus returns to its initial position shown in full lines on the drawings.

When carriage 2 reaches the end of track I, it is stopped by part 34, the grab opens and opening cable 8 becomes slack. Pulley 33 resting on this cable and being urged by counterweight 32 takes the position shown on the drawings by the dotand-dash lines and drives at the same time cable 21, which acts upon lever 24 secured to shaft 2| and again operates the reversing switch and reverses the lifting motor.

The grab rises and the opening ring again making contact with lever 12 produces a new reversal of the motion, the grab again descends in the open position upon the goods and so on.

Should it be desired, provision can be made of a mechanism or a safety switch permitting of stopping the plant in the case of a breakdown.

This switch may consist for instance of a calibrated spring 35 mounted around a rod 36 and located between a lug 3'! and a stop 38. This spring is so calculated that under a normal load corresponding to the filled grab, the compression thereof should for instance correspond to onehalf its effective length.

If, for any reason, this load increases and if the switch controlled by shaft 2| should not work, the carriage continuing its upward movement will compress spring 35 and push rod 36 until it makes contact with and actuates a control switch 39 thereby opening the circuit of the entire plant, and preventing all improper handling and any accident. a

It. will thus be possible to set the apparatus again in motion only after the cause of the incident will have been found.

Fig. 3 shows an example of a plant comprising the arrangement in conformity with the invention.

According to this figure, the device is adapted to operate with the grab I0 and the carriage slides on beam i. This beam is supported by a wall 40, and a structure 4|. This structure 4| is located above a hopper 42 adapted to receive the ashes or the like which are shown at 43 as being disposed inside a we11 44.

The motor 45 is disposed on a platform 46 and is'controlled by a manually operable switch 41 interposed in the supply circuit of the motor 45. This switch is actuated only twice: at the beginning and at the end of the work which is to be performed.

Obviously, the invention is by no means limited to the. embodiments decribed and represented, which are given solely by way of example.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In an automatic control device for single rope grabs, an inclined track extending over the loading and the discharge points, a carriagerolling on this track, an opening member suspended from this carriage and adapted to carry the grab, said carriage descending the track under the sole action of gravity, a winch for the usual rope of the grab, a motor for this winch, a reversing switch for this motor, a first motor control transmission system acting upon said switch for causing the motor to effect the unwinding of the rope during the descentof the carriage on the track, said transmission system being actuated by said opening member at the time when the grab gets hooked to it, and a second motor control transmission system also acting upon said switch for the reversal of the movement of said motor in order to cause the carriage with the grab to return to the upward end of the track, said first system comprising a lever, reaction means on said lever for urging it into a determined position and flexible means by which said system acts upon said reversing switch, whereas said second system comprises a bell-crank lever, reaction means on one arm of said lever causing the second arm to bear against the lifting rope of the grab and means transmitting the pivoting movement of this lever to said reversing switch.

2. In an automatic control device for single rope grabs, an inclined track extending over the loading and the discharge points, a carriage rolling on this track, an opening member suspended from this carriage, and adapted to carry the grab, said carriage descending the track under the sole action of gravity, a winch for the usual rope of the grab, a motor for this winch, a switch mechanism controlling the direction of rotation of this motor, a first motor control transmission system acting upon said mechanism for causing the motor to effect the unwinding of the rope during the descent of the carriage on the track, said transmission system being actuated by said opening member at the time when the grab is engaged in it, and a second motor control transmission system also acting upon said mechanism for the reversal of the movement of said motor in order to cause the carriage with the grab to return to the upward end of the track, said transmission system being acted upon by the said rope when this latter is slack, said first system comprising a movable member pivotally mounted on the usual frame of theplant using said device, a counterweight on said member and means by which said movable member is actuated by said opening member when this latter is lifted under the action of the lifting rope of the grab, said latter means acting between said movable and opening members and including an oscillating member, a flexible part acting between said movable and oscillating members, a reaction means on said oscillating member having a force which is inferior to the one of said counterweight, and a second oscillating member acted upon by said first oscillating member for actuating said switch mechanism for causing the reversal of the motor.

3. In an automatic control device for single rope grabs, an inclined track extending over the loading and the discharge points, a carriage rolling on this track, an opening member suspended from this carriage and adapted to carry the grab, said carriage descending the track under the sole action of gravity, a winch for the usual rope of the grab, a motor for this winch, a reversing switch for this motor, a first motor control trans mission system acting upon said switch for causing the motor to effect the unwinding of the rope during the descent of the carriage on the track, said transmission system being actuated by said opening member at the time when the grab gets hooked to it, and a second motor control transmission system also acting upon said switch for the reversal of the movement of said motor in order to cause the carriage with the grab to return to the upward end of the track, said first system including a lever, reaction means on said lever for urging it into a determined position and flexible means by which said system acts upon said reversing switch, said second system including a bell-crank lever, reaction means on one arm of said lever causing the second arm to bear against the lifting rope of the grab and means transmitting the pivoting movement of this lever to said switch, and another switch at the end of the rising stroke of the carriage adapted to be directly acted upon by the carriage for stopping the whole plant in the case of a breakdown.

4. A device according to claim 3, wherein said latter switch comprises a calibrated spring, and a movable member directly acting upon the electric feeding circuit of the motor when the spring is abnormally compressed.

PIERRE JEAN-MARIE THEODORE ALLARD.

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