US1930707A - Car dumper - Google Patents

Description

06L 17, 1933. R 5 BROWN 1,930,707

CAR DUMPER Filed Sept. 7, 1929 3 Sheets-Sheet l D INVENTOR Oct. 17, 1933. R E BRQWN 1,930,707

CAR DUMPER Filed Sept. 7, 1929 3 Sheets-Sheet 2 CRADLE COUNTER WEIGHT i l t 1 l I l I INVENTOR R. E. BROWN Oct. 17, 1933.

CAR DUMP ER Filed Sept. 7, 1929 3 Sheets-Sheet 3 7 rd 4 g 5 .ii p 6 3 1+1 :4 "I 4 4 a 4 Patented Oct. 17, 1933 UNITED STATES PATENT OFFICE CAR DUMPER Raymond E. Brown, Pittsburgh, Pa., assignor to Heyl & Patterson, 1110., Pittsburgh, Pa., a corporation of Pennsylvania Application September 7, 1929. Serial No. 391,009

This invention relates to car 5 Claims.

dumpers, and

particularly to a number of features whereby the load on the hoist ropes is reduced and the life of such ropes is materially extended.

In car dumpers of the type having a cradle arranged to be hoisted and tilted, the hoist ropes are subject to extremely adverse service are, with constructions now in heavy impact. sary with such constructions to operation of the car dumper at in the operating cycle. By reas use, subject to Because of this fact it is necesslow down the certain points on of the high accelerations and decelerations of the ropes and the high speeds employed with or dinary rope arrangements and reeving, the wires making up the hoist ropes are subject to high strains. Re-

cent investigations show that acceleration stresses in hoist ropes frequently raise the rope load to several times the figur e indicated by the formulas in common use. It is therefore important that the high speeds and high accelerations and decelerations be reduced.

In most rope arrangements the wear is concentrated on one quadrant of the rope and the latter is also subjected to reverse bends.

Both

of these conditions contribute toward shortening the rope life.

It is common practice to arrange a number of hoist ropes in parallel, and further difficulties are encountered by reason of the unequal distribution the several ropes.

The first cost of a set of cm of the load on dle hoist ropes may range from $1,200.00 to in excess of $3,000.00, and the time required for replacement varies from six to twenty-two hours.

I provide a number of features of car dumper construction whereby the many objections to present constructions are overcome.

I reduce the maximum load on the ropes by utilizing the counterweight to assist in the tilting opera- In the preferred form of the invention connected near plate and well cradle so that after engaging e moment arm of the counterweight rope increases and the counterweight does a large part tilting the cradle.

It is common practice to ex of the work of tend the hoist ropes at the rear of the cradle underneath the same or to attach them to a beam which projects from below the cradle. Neither of these methods is satisfactory. The first of them introduces two more sheaves into the rope system, and the second scheme requires the slowing down of the cradle motion before the cradle makes contact with the beam while the cradle is being tilted back to its normal position. If this slowing down is not effected an injurious impact results when the outer edge of the cradle strikes the beam. The slowing down of the operation not only wastes time, but requires an additional deceleration and acceleration of the ropes, thus throwing more load on them. According to my invention the rear sheaves are connected by flexible tension members which are dead-ended under the cradle and extend around curved faces thereof. Preferably, lengths of wire rope attached to links are employed. This concentrates the minimum possible mass at the point which first comes in contact with the cradle when it is returned from the dumping position, and I thus avoid the necessity of reducing the speed at this time.

I preferably employ a four-part rope system for hoisting the cradle, the rope being deadended at the spill plate side, there being two bights of rope at the spill plate side and at the rear side of the cradle. With this arrangement the maximum rope speed is only a little more than half of that required by sevenpart reevings now in common use.

The sheaves are preferably so arranged that the wear over different face portions of the rope is well distributed. If we considered the surface of a wire rope as being made up of four quarter circles and arrange the sheaves so that difierent quadrant faces of the rope are engaged by different sheaves, the total wear on the wire portions in any given quadrant may be materially reduced. In practice it is impossible to divide the rope wear over all four quadrants, but by proper spacing of the sheaves one from the other the amount of rope which passes over more than one sheave can be reduced to a minimum, and in those portions of the rope wherein the maximum wear occurs an arrangement of sheaves, as hereinafter described, so divides the rope wear over different quadrants that the life of the ropes is greatly lengthened as compared with ordinary practice.

It is highly important that the number of reverse bends in the rope be reduced to a minimum, and by distributing the wear over dlfferent quadrants and reducing the number of repeated stresses the service conditions are also vastly improved. As an example, in a car dumper using a 6x19 wire rope 1 diameter on sheaves, and a direct load of, say, 22,000 lbs. on the rope, we have a tensile fiber stress in the wires of 35,000 lbs. per square inch. If we designate four points spaced degrees apart around the circumference of an individual wire as a, b, c and d, we have a fiber stress in the whole wire of 35,000 lbs. when the rope is straight, whereas when passing over a sheave where a is the outside fiber, it has an additional stress of 19,000 lbs., making a total of 54,000 lbs.

If a given part of the rope passes over three sheaves, bending it in the same direction each time, the fiber a has three cycles of stress variation from 35,000 lbs. to 54,000 lbs. and back. If, however, a sheave is placed in a plane at 90 degrees to the other two, the fiber a is on the neutral axis of the wire while passing over this odd sheave, and the fiber at then has only two cycles of variation in stress instead of three during each operation of the car dumper. As a piece of steel wire will withstand only a given number of applications of a certain stress, it follows that by reducing the number of applications of maximum stress, the rope life is materially increased.

As above stated, it is common practice to use a number of ropes in parallel. The loads on car dumpers for the large car sizes now in use are such that even with hoist ropes of the highest grade plow steel 1%" diameter a total of 24 parts of rope are necessary if the rope loading is kept down to a point which will give reasonable life. With four-part reeving this requires three separate ropes at each end of the cradle. It has been attempted to divide the load among the several ropes by the use of equalizers, but these have not functioned satisfactorily because of the design of the sheaves According to the present invention the sheaves are so arranged that the equalizers are made effective. In the ordinary one-piece sheaves having three grooves machined in the rim, a slight difference in groove diameters due to wear on the sheave, or even a difference in the diameters of the ropes due to stretch and wear, will in a few revolutions of the sheave cause the loading of one or two of the ropes to increase in such amount that one rope will slip around the sheave. The same undesirable condition results from the use of three independent sheaves keyed to the shaft. It is impossible to use separate loose sheaves on the same shaft because of space limitations. I provide a sheave comprising a wheel having a rim with separate groove rings mounted thereon, the rings being independently and freely movable. The rings are preferably made and maintained freely movable by provision for a supply of lubricant around the entire periphery of the wheel on which the rims or rings are carried.

In the accompanying drawings illustrating the present preferred embodiment of the invention,

Figure 1 is a perspective view showing my improved rope system;

Figure 2 is an end elevation of the cradle showing the connections of the hoist ropes and the counterweight ropes thereto;

Figure 3 is a diagram illustrating the distribution of rope wear;

Figure 4 is a side elevation partly broken away of one of the improved sheaves employed in my rope system;

Figure 5 is a sectional view taken on the line V-V of Figure 4; and

Figure 6 is a view to enlarged scale of a portion of Figure 5.

Referring first to Figures 1 and 2, there is shown a cradle 2 having a spill plate 3 and carrying a platen 4 on which a car E is placed for dumping. Substantially half of the cradle is shown in Figure 1. The hoist and counterweight rope connections shown are duplicated at the other end of the cradle.

Three hoist ropes 5, 6 and 7 are arranged in parallel at each end of the cradle. They extend from a hoisting drum 8 upwardly over a sheave 9, thence inwardly to a point above the cradle 2 and around a sheave 10. They then pass over a sheave 11 and downwardly to a sheave 12. The sheave 12 is carried in a block 13 secured to the outer ends of flexible cables 14. The cables extend around curved portions 15 formed on the rear side of the cradle 2 and are connected at 16 to links 17 pivoted to the cradle at 18.

From the sheaves 12 the ropes 5, 6 and 7 extend upwardly to a sheave 19, thence over a sheave 20 and downwardly to a sheave 21. The sheave 21 is mounted on the upper end of a link 22 pivotally connected to the cradle at 23. The point 23 is at the upper end of the spill plate 3 and adjacent the hinge pin 24 of the cradle.

From the sheave 21 the ropes extend upwardly around a sheave 25 and thence to a three-part equalizer 26 where they are dead-ended.

One of the cradle counterweights is shown at 27. The counterweight ropes 28 extend over sheaves 29 and 30 to a link 31 which is pivotally connected to the cradle at 32. The pivot point 32 is adjacent the spill plate and well below the hinge pin 24. As shown in Figures 1 and 2, the effective moment arm of the cradle counterweight for rotating the cradle is very low when the cradle is in its normal hoist position of Figures 1 and 2. However, when the hinge pin 24 reaches the pan girder and the tilting commences, the point 32 swings rapidly to the right as viewed in Figures 1 and 2 and the moment arm increases correspondingly, thus materially aiding in the tilting operation and reducing the load on the hoist ropes.

The clamp counterweights are indicated diagrammatically at 33 in Figure 1 and the drum counterweight is shown at 34.

Figure 3 indicates in diagram a cross-section of a hoist rope, the four quadrants thereof being indicated by A, B, C and D. Considering the showing of Figure 3 to be a section, properly oriented, of a portion of the hoist rope between the drum 8 and the sheave 9, it will be seen by tracing through the reeving of Figure 1 that the quadrant A contacts with the sheave 9 and is subjected to wear, and that the quadrant A is also subjected to wear on the sheaves 11, 19 and 20. On the sheaves 10 and 21 the quadrant D is subjected to wear, and on the sheave 12 the wear is on the quadrant B.

Of course, the same section of rope does not pass over all of these sheaves. However, with the normal amount of hoisting of the cradle a section of rope between the sheaves 12 and 19 will be subjected to the maximum wear as it will pass over the sheaves 12, 11, 10 and 9 on hoisting and over the same sheaves in reverse order on lowering. The wear on this section of rope is shown on Figure 3. It will be noted that while the quadrant A is subjected to the wear of two sheaves, this quadrant is not subject to reverse bending. Reverse bending occurs in a plane at 90 degrees to the quadrant A since the quadrants B and D are both engaged by sheaves. However, neither of the quadrants B or D is subjected to the wear of more than one sheave.

The sheave 25 is substantially inactive. The sheaves 9, 11, 19 and 20 are substantially parallel and may be considered as one group, while the sheaves 21, 12 and 10 all lie in planes at substantially right angles to the planes of the sheaves in the group 9, ll, 19 and 20 and form a second group. It may be said, therefore, that substantially half the sheaves engage the rope on one diameter thereof and the other half engage it on the other diameter thereof. Considering particularly that portion of the rope which is subject to maximum wear, the sheaves which engage it are so arranged that the rope quadrant engaging the maximum number of sheaves is free of reverse bends, and conversely, those quadrants of the rope which are subjected to reverse bends do not engage more than one sheave.

It is highly important that the load be uniformly divided between the several ropes 5, 6 and 7. This is accomplished by a special sheave arrangement shown in Figures 4 to 6, inclusive. Each sheave comprises a wheel or spider having a hub 35 and a rim 36 with a flange 37 formed on one side thereof. Sheave rings 38 which are circumferentially grooved at 39 to receive the hoist ropes are fitted over the periphery of the rim 36 and are held in place between the flange 37 and a clamping ring 40 which is secured to the rim by bolts 41. Grease channels 42 extend entirely around the rim 36, there being a channel under each ring 38. Each channel 42 is connected through a hole 43 to a fitting 44 whereby lubricant under high pressure may be supplied to the channel 42. Since the lubrication is extended entirely around the rim 36, there is no danger of the rims freezing onto the wheel and free movement of the rings relative to the wheel and to one another is always assured.

Experience with an installation of the character herein described shows the value of the several features herein described. In that installation one of the three hoist ropes was inadvertently damaged, but instead of replacing it, as would be necessary with ordinary constructions, the car dumper was kept in operation until this one hoist rope broke. Despite the damage which the rope had suffered its life was in excess of that ordinarily expected for hoist ropes. A single new rope was installed, whereas with ordinary installations it is always the practice to replace all the ropes when one of them breaks.

The new rope stretched to a certain extent and all of its elongation was carried back to the equalizer and there automatically taken up. When the limit of the equalizer was reached the new rope was shortened and the equalizer continued to take up elongations in it until it had been fully stretched.

This experience demonstrates that the ropes in the car dumper herein described are subject to extremely favorable working conditions, that the load is equally distributed among them, that slackness in any particular rope may always be taken up by the equalizer because of the special sheave construction employed, and that the life of the ropes is increased far beyond the accepted normal figure. By reason of this fact expensive and frequent delays in operation are obviated.

I have illustrated and described the preferred embodiment of the invention and the several features which contribute toward the desired result. It will be understood, however, that many of these features are of value when used alone and that the invention may be otherwise embodied within the scope of the following claims.

I claim:

1. In a car dumper, a cradle adapted to receive a car and to be lifted and then tilted therewith, a hoist rope anchored above the cradle passing down to and under a sheave connected by a tension member to the front of the cradle, said sheave being in a plane parallel to the length of the cradle, thence passing upwardly and over two transversely placed sheaves, then down to the rear of the cradle and under a sheave parallel to said first-mentioned sheave, upwardly to a transversely placed sheave substantially vertically above the rear of the cradle, and over said sheave to the front of the cradle, around a sheave lying in a substantially horizontal plane and thence over a vertical sheave and thence downwardly to a hoisting drum.

2. A car dumper as claimed in claim 1, having a plurality of hoisting ropes arranged in parallel with an equalizing anchorage for the stationary ends of the ropes.

3. In a car dumper, a lifting and tilting cradle and a hoist therefor including a plurality of ropes secured to an equalizing anchorage above the cradle, and passing around a sheave at right angles to the cradle, down to a sheave parallel to the cradle, upwardly therefrom and over a pair of sheaves parallel to the first-mentioned sheave, down around a sheave at the rear of the cradle parallel to the second-mentioned sheave, upwardly therefrom, and over other sheaves to a hoisting means.

4. In a hoist for a lifting and tilting car dumper, sheaves secured to the front and back of the cradle parallel thereto, sheaves at right angles to the cradle for feeding a hoist rope to the first-mentioned sheaves and conducting it therebetween.

5. In a car dumper hoist, sheaves adjacent the front and rear of the dumper in planes parallel to the length thereof, a cable traversing said sheaves, a sheave above one of the first-mentioned sheaves and at right angles thereto for guiding the cable from the first-mentioned sheaves, and a pair of sheaves above the firstmentioned sheaves and at right angles thereto for guiding the cable from one to the other of the first-mentioned sheaves.

RAYMOND E. BROWN.

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