US1170463A - Hoisting machinery for operating grab-buckets. - Google Patents

Description

' A. SMITH. HOISTlNG MACHINERY FOR OPERATING GRAB BUCKETS.

APPLICATION FILED MAY 4. I912.

1mm. Patented Feb; 1, 1m

3 SHEETS-SHEET 1.

Iii/a ATTOR/VE Y5 1,170,463, I Patented Feb. 1, 1916.

A: SMITH. I HOlSTING MACHINERY FOR OPERATING GRAB BUCKETS.-

APPLICATION FILED MAY4| 1912.

3 SHEETS-SHEET 2.

- BY W %Z% Mnrronmrs VA. SMITH. I HOISTING MACHINERY FOR OPERATING GRAB BUCKETS.

APPUCATION FILED MAY 4, 1912.

L10A63, Patented Feb. 1, 1916.

3 SHEETSSHEET -3- W/TNESSES lNl/EIi/TOR are ears an no.

AUGUSTUS SMITH, oE onrn PLAINEIELnMW JERSEY, ASSIGNOR T0 BERGEN rom'r mun woaxs, 0E BAYonnE, NEW JERSEY, a coar'onarron or new JERSEY.

HOISTING- MACHINERY-FOR OPERATING GRAB-BUCKETS.

Specification of Letters Patent.

Patented Feb. 1, 1916.

Application filed May 4, 1912. Serial No. 695,079.

To all whom it may concern 'Be it known that l, AUGUSTU SMITH, a citizen of the United States of America, and residing at North Plainfield, in the. county of Somerset and State of New Jersey, have invented a certain new and useful Improvement in Hoisting Machinery for Operating Grab-Buckets, of which the following is a specification.

Grab shovels or buckets for digging coal, ore or similar materials are usually operated by two ropes or chains, one attached to the frame of the bucket hereinafter referred to as the holding rope which hoists and lowers the whole bucket and the other rope hereinafter, called the closing rope attached to some gear within the bucket for drawing the jaws together to make it dig into the matter that is handled. These ropes are generally wound each on a separate drum actuated through some frictional device from a power shaft driven either by belt, steam engine or electric motor. Levers in the hands of the operator suitably connected to the friction clutches in the hoisting machine give the operator extreme delicacy of control of the movements of the bucket, he being thus able to hoist or lower the bucket or to open and close it at will. The horizontal movement of the bucket is often controlled by a trolley which is sometimes moved by a separate engine or motor or'sometimes by a device such as the differential drum described in McIntyre Patent No. 1,004,451 connected by gearing to the holding drum of the hoisting mechanism. The apparatus for moving the bucket horizontally has nothing to do with my present invention, and for the purpose of simplicity, I have omitted the ropes leading from the .difierential drum, which I prefer to use, to the trolley and likewise all suggestion of an independent control of the trolley by a separate'engine.

A grab bucket for hoisting coalusually weighs about twice as much as the coal it can hold, and therefore the hoisting engine has to be powerful enough to lift about three times the net weight of the coal which power could be saved if a counterweight could be made use of. The great difliculty in using a counterweight, however, has been that the digging power of the bucket into the coal or ore is a function of its weight, and-if the counterweight acted so as to make the bucket rest lightly on the materialto be excavated,

the bucket would have no digging power and could not fill itself. Another difiiculty that has heretofore been encountered in mechanisms of this character is in the lowering of the empty bucket. Friction clutches or brakes, or both, are commonly used for this purpose which waste a great deal of power and give trouble by heating; motors are sometimes used to absorb the energy of the falling bucket by creating negative electrical energy, and reversing steam engines are sometimes used in a similar way. All of these methods involve numerous mechanical or electrical difliculties and are objectionable for one reason or another. I

One object of my invention is to introduce a counterweight in such a way that the full weight of the bucket will rest on the material to be excavated but so that the counterweight will come into play when the bucket is to be hoisted, the present arrangement be-,

ing such that the counterweight is lifted when the bucket is lowered, thus avoiding all the difficulties involved by the methods above mentioned. Another object of my invention is to eliminate the friction clutches between the winding drums and the driving shaft so that the number of levers to be manipulated by the operator will be thereby reduced, while at the same time the cost and weight of the hoisting mechanism is thereby reduced. I

In the accompanying drawings, Figure 1 is a diagrammatic representation of a clam shell grab bucket with hoisting and closing ropes wound on separate drums, and a differential drum geared to the holding drum for controlling the horizontal position of the trolley, the connection to which is omitted for the sake of clarity; Fig. 2 is a plan of the drum arrangement; and Figs. 3 and 4 are plans of modified drum arrangements.

Referring to the drawings in greater detail, Fig. 1 is a diagrammatic representation of a clam shell grab bucket with its hoisting and closing ropes 11 and 12 respectively wound on separate drums 13 and 14, driven independently by the power shafts 15. The difierential drum 16, geared to the holding drum 13, controls the horizontal position of the trolley, (not shown), the connection between the two being omitted for clearness. A counterweight 17 to offset the empty bucket is shown attached to the holding drum 13. Fig. 2 is a plan view of this hoisting mechanism drawn to a larger scale. .An electric motor 18 (which may obviously be substituted by a reversible steam engine) is shown directly connected by spur gearing 19 to the holding drum 13 and. a similar motor 20 (or reversible steam engine) is shown directly connected by spur gearing 21 to the closing drum 14. The differential drum 16 is geared at 22 to the holding drum in 13. A friction clutch 23 is introduced for locking the two motor shafts together'at the will of the operator when it may be desirable to have the drums 13 and 14 revolve together, as in hoisting after the bucket is {6 closed, or Inore particularly in lowering the empty bucket. If this clutch were omitted, one mOtor or steam engine might tend to drive its drum faster than the other and thus cause the bucket to open or close or .0 one of the operating ropes to become slack. .In the machine shown in Fig. 2, the closing motor 20 has to be large enough to close the [bucket alone by means of the drum 14 which requires considerably more power than is 85 necessary subsequently to lift the bucket when the holding motor is assisting.

Fig. 3 is a plan view of another arrangement drawn to'a somewhat largerscale. In

this case the motor 24 which drives the hold- U ing drum 25 also drives the differential drum D, and the main spur wheel 26, which is rigidly connected to the bevel wheel 27 of i an equalizing gear mechanism. The motor 28 drives a gear 29 which is keyed to the i5 shaft 30 of the closing drum 31 and turns with it the bevel gear 32 whichis keyed to the same shaft. Engaging between the gears 27 and 32 are intermedlate bevel gears 33, 34, of the planetary type carried by a 0 face plate 35 bolted to the closing drum 31, .the mechanism being such that when the motor or engine 28 revolves the shaft 30 the closing drum 31' will revolve at less speed .but with greater pulling power. In the arrangement of gears shown, the closin drum 31 will revolve at one half the spe d and with twice the pulling power it would if the r motor 28 drove it directly as in the case shown in Fig. 2 providing always that the abutment gear 27is held stationary by the gear 26 which is locked to the holding drum. Instead of the bevel gears shown in this figure for the sake of clearly illustrating the relative motion of the closing drum and its shaft, gears of any planetary type could be used and-any desired ratio obtained in the relative rotations and torques of shaft 30 and drum 31. In this case a friction clutch can be introduced at 36 looking the closing .9 drum 31 to the gear wheels 29 by means of the friction surface 37, which by reason of the train of gears shown will lock drums 25 and 31 together with the same effect and for the same purpose as the friction clutch 23 l shown in Fig. 2.

In both of the arrangements illustrated i in Figs. 2 and 3 it is necessary for the holding motor 18 or 24 to be started immediately after the bucket is closed so that it may assist the closing motor to lift the bucket as well as to prevent the holding rope from becoming slack and entangled in the bucket for the reason that the continued rotation of the closing motor begins to lift the bucket the instant after the jaws meet. When -motors or steam engines of large size are used and especially in the case of motors, it

1s impossible to accelerate the holding motor by the fact that when the bucket is burying itself in the material to be excavated, the frame of the bucket to which the holding rope is attached actually sinks so that rope has to be paid out by the holding drum-if the bucket is to get its full load which means that the holding motor hasto revolve in the direction to lower the bucket, while the closing motor is revolving in the direction to close the bucket, which is the same direction of rotation that is required to lift it. Hence a if the holding motor or engine be directly geared to the holding drum, asshown in Figs. 2 and'3, it must actually be reversed and then brought to speed to catch up With the closing motor. In the case of large motors or engines this is very diflicult if not impossible to accomplish and hence the common use of the friction clutch by means of which the holding drum can be started with less inertia and the closing drum checked a little if necessary until the holding drum can take its share of the lift. Fig. 4 shows the arrangement I have-invented for'overcoming this difficulty notwithstanding the size and inertia of the motors or engines.

The reversible motor 38 or steam engine is geared by means of the gear wheels 39 and 40 to the shaft 41 on which is keyed a counterweight drum 42 and a ratchet wheel 43. The holding drum 44 on which the holding rope is wound is not keyed to the shaft 41,

but is loosely mounted on it, and arranged to be revolved by pawls 45 engaging the ratchet wheel 43 so that when lifting the bucket the pawls will engage the ratchet wheel and cause drum 44 to revolve with it but so that the pawls will travel freely over the ratchet if the holding drum 44 should tend to turn in the hoisting direction under some other force. f

The differential drum 46 which I prefer to use for regulating the horizontal posi tion of the bucket is drum 44 so as to revolve with it in some,

geared to the holding fixed ratio as by means of spur gears 47 and 48, 47 being bolted to the holding drum 44. The closing drum 49 is loosely mounted on the shaft 41 and driven by planetary gears similar to those shown in Fig. 3. In this case the abutment bevel gear 50 is keyed to the shaft 41 and is held stationary by the holding motor 38 when the latter does not revolve. The bevel gear 51 is bolted to the spur wheel 52, driven by the spur pinion 53 on the closing motor or engine shaft 54. Planetary gears 55 and 56 carried by a disk 57 bolted to the closing drum are meshed with gears 50 and 51 so that when the abutment gear 50 is held stationary and the driving gear 51 turned by the motor 54, the planetary disk between them and the closing drum with it will revolve at one half the speed of 51 and with twice the pulling power. As in Fig. 3 any other system of planetary gears could be substituted for the bevel gears to accomplish the same result.

Friction of the necessary amount is intro duced between the holding drum 44 and closing drum 49, as for instance by friction surfaces 58 turned in the adjacent flanges of the drums and a coil spring 59 acting to force drum 44 against drum 49 so that when drum 49 revolves, drum 44 will be subjected to a drag tending to make it revolve simultaneously. Now when the closing drum 49 is revolved by motor or engine 54 causing the bucket to close and dig into the material to be excavated, the holding drum 44 will tend to turn with it sufliciently to keep the holding rope always tight but not with sufficient force to materially lift the bucket. As

above mentioned, the holding. drum 44 is free to revolve in this direction, its driving pawls slippin over the ratchet wheel 43 which is stan ing still or, it may be, even backing down in case it should be necessary to reverse the holding motor 38 so as to give out sufficient slack rope to permit the bucket to sink into the material as the jaws are closed by the closing drum.

As soon as the jaws of the bucket meet,

the continued revolution of the closing drum will commence to lift the bucket and will drag with it the holding drum 44 keeping the holding rope always taut, the pawls slipping as fast as necessary over the ratchet wheel 43. When the bucket has been closed, however, the holding motor 38 will be reversed if it has been backing down or would be started, if at rest, in the direction to hoist the bucket and would be brought up to speed as rapidly as it can be accelerated. The speed of rotation of the closing drum 49 which was half that of the gear wheel 51 -when the motor 38 was at rest will gradually be accelerated as gear wheel 50 is accelerated by motor 38. Notwithstanding .thereafter motor 38 be excavated with the the bucket, motor 54 this, motor 38 will rapidly overtake motor.

54 in speed until the ratchet wheel 43 revolves as fast as the holding drum 44 when the ratchet wheel will pick up the pawls and and the counterweight on drum 42, if one be used, will assist motor 54 in lifting the loaded bucket. As soon as 5 motor 38 drives the shaft 41, and the bevel gear 50 keyed to it, at the same angular velocity, as bevel gear 51 is driven, the relative motion in the planetary gears will cease and both motors and the counterweight, if there be one, will loaded bucket. The counterweight may be made to balance the empty bucket and all of the friction of the machine, if necessary, so that the motors will be called on to lift only the net Weight of the material to be hoisted. The motor 54 will be of suflicient size to cause the bucket to dig into the material to assistance only that is afforded by the planetary gears. To open can be checked or stopped and the continued winding in on the holding line by motor 38 will transfer the weight of the bucket to the holding drum 44 causing the bucket to open, or if the holding drum 44 be stopped, opened by reversing the direction of rotation of motor 54 and the closing drum. When the bucket has been opened both m0- tors must be reversed together to return the empty bucket down to the material to be excavated. In returning the empty bucket, its weight will be mostly carried by the holding drum 44, the pawls coming into play on the ratchet wheel to resist the weight of the bucket. In lowering the bucket, motor 38 will have to lift the counterweight by means of the counterweight drum 42 and if the counterweight be large enough to over-balance the bucket to the extent of the friction of the machinery, motor 54 will evidently have to overcome, on the return of the bucket, this surplus weight of the counterweight as well as the friction of the machine when returning. Motor 54 in act together to lift the the bucket can be.

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returning the bucket will have to overcome only the friction of turning its own drum and gears so that there will be difliculty in compellmg the two motors to run at exactly the same speed. This difliculty will be I allowlng the bucket to open or close or one rope to become slack, additional friction may be applied by the thrust collar 60 working through the ratchet wheel by thrust pins on the coil spring 59 to produce any required friction at the" surface 58, this device being equivalent to. the friction clutchesplication of my invention in which motors or steam engines are employed directly geared to the holding and closing drums of a hoisting machine with a counterweight on the holding drum, or geared to it, opposed to the-weight of the bucket. I propose to operate the closing and holding ropes of the hoisting machine independently by reversible motors or steam engines or other driving power and to counterweight the holding drum so that the weight of the empty bucket may be offset in lifting and so that the falling weight of the empty bucket in lowering will not have to be absorbed by any frictional clutches, brakes, dynamic energy or by the backing down of a steam engine or similar expedient. My apparatus, when sufficient counterweight is used, will require positive energy in lowering the empty bucket and lifting the counterweight. It

will require also positive energy for lifting the loaded bucket but only about one-third of that required by the machines in common use, if the bucket be fully counterweighted.

In the simplest form of my invention as illustrated in Fig. 2, I provide. suflicient power in the closing motor 20 to cause the bucket to dig into the material to be excavated without any auxiliary mechanical advantage, and I provide sufficient accelerating means onthe holding motor 18 to cause it to overtake the closing motor within a reasonable time after the latter has closed the bucket and caused it to start upward. In the improved form of my apparatus illustrated in Fig. 3, I provide a mechanical advantage to assist the closingmotor in cansing the bucket to dig into the material to be excavated, this mechanical device being automatically turned out of gear as soon as the holding drum has wound in the slack holding rope and overtaken the closing drum.

In the third form of my apparatus which is the only one suited for large machines, I provide means for permitting the holding drum to revolvewith the closing drum with sufficient power to prevent any slack in the holding rope but without pulling so hard on the bucket as to materially decrease its digging power. In this form I may or may not also provide a mechanical device to give the closing motor additional power to close the bucket which is automatically thrown out of operation when the holding motor is working with the closing motor to lift the bucket.

I do not wish to limit myself, however, to

the particular arrangement or mechanical devices shown 1n these drawings or described in the above specifications, the arrangements selected for illustration being merely to explain the principle involved.

In the Figs. 2, 3 and' I have indicated solenoid brakes on the motors by the letter S. It is desirable to have solenoid brakes to hold either motor still when the current is cut off as well as to hold it in case of failure of the current. In the case of a reversing steam engine the same result would be accomplished by throwing the valve mechanism to the neutral position.

In the foregoing description and in the figures I have shown and described a counterweight as being used in connection with the holding drum and as this is of obvious The use of a counterweight, however, is not an essential part of my apparatus for it is evident that if the closing motor be made large enough to lift the bucket without the counterweight there is nothing to prevent doing so, and for lowering the empty bucket without a counterweight, the negative resistance of a motor or a steam engine or even a friction brake could be made use ofas is done in mostof the machines now in use. It might be, furthermore, advantageous in some instances to omit the counterweight as in the case where the horizontal movement of the bucket is considerable when compared with its vertical movement. In such cases the independent control of the holding and closing drums by separate motors Without a counterweight would not benew and the invention herein described would only apply if some mechanical means such as the planetary gears were introduced to assist the closing motor to cause the bucket to dig into the material which mechanical means were afterward thrown out of action when the holding drum was brought up to speed or this invention would be involved in case the holding drum were connected to its driving power in such a way as to permit it to overrun its driver under the influence of some part of the closing mechanism for the purpose ofkeeping the holding drum rope tight until the holding motor could be brought up to proper speed.

I claim as my invention,

1. A hoisting mechanism comprising separate holding and closing drums, separately controlled reversible motors for driving the same, and an equalizer gearing connecting other standing, together with a counterweight operatively connected to the holding drum.

3. A hoisting mechanism comprising separate holding and closing drums, separately controlled reversible motors for driving the same, and an equalizer gearing connecting the closing drum with both motors whereby said drum may be driven at half speed with full torque by either motor running and the other standing, together with a clutch for locking one drum system to the other.

4. A hoisting mechanism comprising separate holding and closing drums, separately controlled reversible motors for driving the same, and an equalizer gearing connecting the closing drum with both motors whereby said drum may be driven at half speed with full torque by either motor running and the other standing, together with a clutch for locking one drum system to the other, and a counterweight operatively connected to the holding drum.

5. A hoisting mechanism comprising separate drums, a frictional drag device between the same, independently-controlled reversible motor means respectively geared to said drums, and comprising for one of said drums a one-way driving mechanism between said drum and its motor, whereby said drum may rotate in advance of its motor under the influence of the drag of the other drum.

6. A hoisting mechanism comprising separate drums, a frictional drag device between the same, independently-controlled reversible motor means respectively geared to said drums, and comprising for one of said. drums a one-Way driving mechanism between said drum and its motor, whereby said drum may rotate in advance of its motor under the influence of the drag of-the other drum, together with means for locking said drum systems together so that the drums revolve in unison.

7. A hoisting mechanism comprising separate drums, a' frictional drag device between the same, .independent reversible motor means respectively geared to said drums, ratchet and pawl mechanism in one of said gear systems to permit the speed of the drum in said system to exceed that of its motor, in combination with means for locking the drum systems together so that the drums will revolve in unison.

8. A hoistin mechanism comprising separate drums, a rictional drag device between the same, independent reversible motor means respectively geared to said drums,

ratchet and pawl mechanism in one of said gear systems to permit the speed of the drum in said system to exceed that of its motor, together with a counterweight operatively connected to said drum to assist the ratchet drive, in combination with means for looking the drum systems together so that the drums will revolve in unison.

9. A hoisting mechanism comprising separate winding drums, a frictional drag device between the same, separately-controlled reversible motor means each geared to one of the windin drums, a ratchet and pawl mechanism 1n one said gear systems to permit the speed of the drum in said system to exceed that of its motor, in combination with a multiplying gear arranged between the respective gear systems but inactive when the drums are running at the same speed, whereby the power of one drum may be increased at the expense of its speed.

10. A hoisting mechanism comprising sep arate winding drums, a frictional drag device between the same, separately controlled reversible motor means each geared to one of the winding drums, a ratchet and pawl mechanism in one of said gear systems to permit the speed of the drum in said system to exceed that of its motor, in combination with a multiplying gear arranged between the respective gear systems but inactive when the drums are running at the same speed,

whereby the power of one drum may be inv to exceed that of its motor, in combination with a multiplying gear arranged between the respective gear system but inactive when the drums are running at the same speed, whereby the power of one drum may be increased at the expense of its speed, together with a counterweight operatively connected to the ratchet controlled drum, and opposed tothe weight to be lifted thereby, and means for locking one drum system to the other.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses.

AUGUSTUS SMITH.

Witnesses:

WALTER Anna, L. Gnorn.

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