US3000577A - Shear pin drive for gyratory crushers - Google Patents

Description

L. R. FERGUSON SHEAR PIN DRIVE ox GYRATORY CRUSHERS Filed July 23. 1959 INVENTOR Lester R. Ferguson 0 BY m zauwamfi x ATTORNEYS 3,000,577 SI-EAR PIN DRIVE FOR GYRATORY CRUSHERS Lester R. Ferguson, Riveredge, N.J., assignor to Kennedy Van Saun Mfg. & Eng. Corporation, New York, N.Y., a corporation of Delaware Filed July 23, 1959, Ser. No. 829,047 Claims. (Cl. 241--32) My invention relates to improvements in gyratory crusher constructions and more particularly to a driving connection directly associated with the eccentric of the crusher and including a safety arrangement provided with shear bolts for avoiding damage to the crusher.

In general, gyratory crushers are very heavy and expensive machines in which a main shaft is oscillated by an eccentric to in turn oscillate a mantle carried by the shaft within a grinding or crushing ring. Such crushers are likely to be damaged very severely if pieces of tramp iron contained in the rock being crushed come between the mantle and grinding ring. Such pieces of tramp iron cause very serious damage where they are so large that they cannot pass between the crushing members even under the give of the springs supporting the main shaft and mantle of the crusher.

Crushers of the type under consideration are particularly the gearless type crushers in which the eccentric is driven by a directly mounted electric motor or by a belt-flywheel drive. These and other parts of the usual driving means are so large in diameter, so heavy, and consequently have such a momentum when in operation that a piece of tramp iron between the grinding elements is bound to and has caused serious damage to the crusher. In such cases the loss is not only for the broken parts of the driving and other equipment but also for the time and expense involved in taking down the crusher and repairing it.

Therefore, the primary object of my invention is to provide a safety structure arrangement in the driving connection to the eccentric which will protect the crusher against damage when some uncrushable object, such as a piece of tramp iron, enters the space between the crushing elements.

A further object of my invention is to provide a safety construction which is easy to install in existing gyratory crushers and easy to include in new crusher constructions.

Another object of my invention is to provide a safety construction of the type referred to, which is readily replaceable when the movement of the crusher mantle is stopped by an uncrushable object between the mantle and grinding ring of the crusher.

-In accordance with my invention the driving connection to the eccentric of a gyratory crusher is provided with a driving dog structure, including shear bolts which are normally adapted to take the driving force for the eccentric but which are adapted to be sheared off when movement of the eccentric is stopped or retarded abnormally, as for example abruptly by the presence of tramp iron or some other uncrushab'le object between the crushing elements of the crusher.

In a particular construction the coupling mechanism or driving coupling between the usual driving disc, driven by a drive pulley or motor attached thereto, includes a driving dog structure keyed to the eccentric and provided with dogs attached to the driving dog structure with shear bolts located in a position to be sheared off when the eccentric encounters unusual resistance, as explained above.

The invention is described more in detail hereinafter in connection With the accompanying drawings illustrating one structural embodiment of the invention.

Patented Sept. 19, 1961 ice In the drawings:

FIG. 1 is a broken view partly in vertical section of the lower portion of a gyratory crusher, in which the invention is illustrated;

FIG. 2 is a horizontal sectional view taken through the driving dog structure on the line 2-2 of FIG. 1; and

FIG. 3 is a broken vertical sectional view taken on the line 3-3 of FIG. 1.

The drawings show only the lower portion of the gyratory crusher to which the features of the present invention are concerned, it being understood that the gyratory crusher includes a main driving shaft carryung a mantle operating within a concave or grinding ring for effecting the crushing of stone of various kinds. In gyratory crushers of this type the main shaft is suspended on springs or other suitable resilient means, so that the mantle has some give vertically during the crushing operation.

The lower portion of the crusher shown in the drawings includes a stationary depending cylindrical annular sleeve member 10 normally comprising an integral part of a bottom plate bolted to the bottom shell of the crusher. The depending sleeve 10 comprises a stationary part of the crusher, and its inner cylindrical surface is lined with a bearing 12, within which an eccentric 14 is rotatably mounted. The eccentric as in known structures includes an inner cylindrical cavity 16 which is off center with respect to the outer cylindrical surface, illustrated in FIG. 1 by showing the wall at the right substantially thicker than the wall at the left.

The main shaft of the gyratory crusher shown at 18 extends, in the usual manner, into cavity 16 of the eccentric 14 and is provided with a sleeve 20 lined with a bearing material 22 fitting the cylindrical outer surface of the main shaft 18. The sleeve 20 comprises a part of a known type ball and socket bearing structure located in the cavity 16 of the eccentric and not shown in the drawings. The ball and socket bearing structure associated with the sleeve 20 and eccentric 14 is off center with respect to the outer surface of the eccentric 14, so that the rotation of the eccentric 14 within the sleeve 10 causes the shaft 18 to oscillate and effect the crushing and grinding, in the usual manner.

The gyratory crusher illustrated in FIG. 1 is of the gearless type having a driving pulley 24 provided with the usual grooves 26 for receiving V belts in the usual manner. The upper part of the pulley 24 is U-shaped in cross section and includes an upwardly-extending sleeve 28 fitting around a bearing sleeve 30 carried on the exterior surface of the static-nary sleeve 10. The lower portion of the stationary sleeve 10 is provided with a lock ring member of known construction, not shown, for supporting an annular bearing unit on which the pulley 24 is supported and operated.

The means for coupling the driving pulley 24 to the eccentric 14 includes a bottom driving disc 32 bolted to the bottom of the pulley 24- by bolts 34. The pulley 24 and driving disc 32 are flanged, as shown, and are secured together in a fluid tight manner by means of the bolts 34. The bottom portion of driving disc 32 is provided at its center with a fitting 36 adapted to provide a stufling box and means for supplying lubricating oil to the interior of the crusher and the bearings referred to above, but all such features have been omitted from the showing in order to avoid confusion, since they have nothing to do with the present invention. The driving disc 32 integrally includes a pair of similar substantially semi-annular spaced supports 38 facing each other and arranged in a circular arc concentric with the axis of rotation of the driving disc 32. The supports 38 extend upwardly from the driving disc and have upper machined surfaces in the same horizontal plane. A dog coupling member so in driving connection with the supports 38 and in driving connection with the lower portion of the eccentric sleeve 14 is mounted on the supports 38 and in turn carries the weight of the eccentric sleeve 14.

The supports 38 are spaced so as to provide slots 42 at 180 with respect to each other serving as keyways to provide a coupling between the driving disc and the dog coupling member 40, the latter of which is generally cupshaped with its upwardly-extending rim 43 cut to provide oppositely-arranged keyways 44 receiving downwardlyextending key projections 46 provided on the lower rim of the eccentric sleeve 14. The coupling member 40 is generally cylindrical in shape and of approximately the same diameter as the lower portion of the eccentric sleeve, and except for the keyways 4 4 and the keys 46, the engaging surfaces of the lower end of the eccentric sleeve and the upper end of the coupling member are horizontal as illustrated.

In accordance with the invention the bottom of the coupling member 40 presents a plain flat surface resting on the upper surfaces of the supports 38, and the engaging surfaces are machined and arranged in a horizontal plane, or at right angles to the axis of rotation of the driving disc 32. The coupling member 40 is connected in driving relationship with the supports 38, which together form a substantially circular structure, by securing dog keys or key blocks 48, located respectively in the slots 42, to the underside of the coupling member as at 180 with respect to each other and at 90 with respect to the keyways 44. The dog key blocks 48, according to the invention, are secured to the bottom of the coupling mem ber 40 by means of shear bolts 50 extending through bores in the inwardly-projecting bottom web 51 of the coupling member and respectively through bores in the dog key blocks 48, as shown in FIGS. 1 and 3 of the drawings.

Each of the shear bolts 50 is mounted in place with upper and lower lock washers 52 and with nuts 54 drilled and held in position by cotter pins 56. The dog key blocks 48 preferably extend the full length and width of the slots or keyways 42 in the manner illustrated in FIGS. 1 and 3 of the drawings. Each of the shear bolts 50 is preferably a stress relieve bolt and provided with a weakening notch at the position of the interface between the supports 38 and the bottom of the coupling member 40. As illustrated in FIGS. 1 and 3, this weakening notch comprises an annular wide oval groove 58 extending completely around the bolt and providing a shearing posi tion symmetrically located at the interface referred to.

The improved safety coupling arrangement supports the weight of the eccentric sleeve from the driving disc 32, which in turn is supported by the pulley 24 carried by the stationary sleeve and provides a flexible connection or coupling between the driving disc and the cocentric sleeve, so that there may be some relative lateral movement between the eccentric sleeve and the coupling member 40 in one direction and between the coupling member 40 and the supports 38 at 90 to said direction. Furthermore, the rotary motion imparted to the driving disc by the pulley 24- is transmitted through the dog key blocks 48 to the coupling member 40 and from this member by means of the keys or projections 46 to the eccentric sleeve 14.

In the operation of the gyratory crusher under normal conditions the shear bolts 50 are adequate to carry the normal rotational load applied to the eccentric sleeve 14, but when an uncrushable object such as a piece of tramp iron, comes between the crushing elements of the crusher and stops the motion of the main shaft 18 and the rotation of the eccentric sleeve 14, the bolts 50 are sheared off at the position of the weakening grooves 58, thereby permitting the continued rotation of the pulley 24 and driving disc 32 without damaging the crusher. The shear bolts for a to ton crusher, for example, are one inch in diameter provided with an oval groove inch wide and cut to leave from 0.55 to 0.65 inch at the shear position.

When the shear bolts 50 are sheared off, the lower portions merely fall into the bottoms of the slots 42. Thereafter, after removing the tramp iron from between the crushing elements of the crusher, the broken shear bolts are readily replaced in a relatively short time by unbolting the driving disc 32 from the pulley and lowering the driving disc, the coupling member 40 and the eccentric sleeve sufficiently to permit access to the coupling member for replacing the shear bolts. Even with a large size gyratory crusher, the shear bolts may be replaced in a matter of two hours, which is nothing compared to the losses which would be incurred if parts of the crusher were wrecked.

While the supports 38 have been described as substantially semi-cylindrical, except for the slots 42, it is to be understood that the support structure may be a cylindrical ring provided with keyway slots in its upper portion corresponding to the slots 42 for receiving the dog key blocks 48 and the lower ends of the shear bolts 50. Furthermore, while the dog coupling member 40 is illustrated as being keyed to the lower rim of the eccentric sleeve, it is to be understood that it may be coupled to such rim in any other suitable manner. It is also to be understood that the safety structure provided by the shear bolts and dog key blocks may be located at the position of the engaging surfaces of the eccentric sleeve and the coupling member 40, inverting the coupling member, instead of in the connection between the driving disc 32 and the coupling member 48, in which case the coupling member 48 would be keyed to the support by means of interlocking keys and keyways. The location of the safety coupling structure in the relationship illustrated is, however, regarded as more convenient.

What I claim is:

1. In a gyratory crusher including an upright main crusher shaft the lower portion of which is surrounded by an eccentric sleeve for gyrating the shaft, a driving pulley for rotating the eccentric sleeve, a rotatable driving disc fixed to the pulley and supporting the eccentric sleeve in operative position around the lower portion of the shaft, and a drive coupling between the driving disc and the eccentric sleeve including a coupling member having a driving connection with the eccentric sleeve and a driving connection with the driving disc, the improve-- ment comprising spaced dog keys mounted on and secured to the coupling member and constituting a part of one of said driving connections of the coupling member, and a shear bolt securing each of said dog keys to the coupling member, said shear bolts carrying the driving load from the driving disc to the eccentric sleeve, whereby said shear bolts are sheared ofi releasing the dog keys from the coupling member thereby avoiding damage to the crusher when an uncrushable object comes between the crushing elements of the crusher.

2. A gyratory crusher as claimed in claim 1, in which the shear bolts are mounted parallel to the axis of rotation of the driving disc and each includes a weakening notch at the position of the interface between the coupling member and the dog key secured by the shear bolt.

3. In a gyratory crusher including an upright main crusher shaft the lower portion of which is surrounded by an eccentric sleeve for gyrating the shaft, a driving pulley for rotating the eccentric sleeve, a rotatable driving disc fixed to the pulley and supporting the eccentric sleeve in operative position around the lower portion of the shaft, and a flexible drive coupling between the driving disc and the eccentric sleeve including a dog coupling member having a driving connection with the lower portion of the eccentric sleeve, the improvement comprising an upwardly-extending support attached to the upper portion of the driving disc on which the dog coupling member is supported, said support having oppositely arranged keyway slots adjacent the dog coupling member, a dog key block in each keyway slot, and a shear bolt securing each of said dog key blocks to the bottom of the dog coupling member, said shear bolts carrying the driving load from the driving disc to the eccentric sleeve, whereby said shear bolts are sheared off releasing the dog key blocks from the dog coupling member thereby avoiding damage to the crusher when an uncrushable object comes between the crushing elements of the crusher. I

4. A gyratory crusher as claimed in claim 3, in which the dog coupling member and the support have plain horizontal engaging surfaces and said shear bolts are each provided with a weakening notch located at the plane of said engaging surfaces.

5. A gyratory crusher as claimed in claim 3, in which the support attached to the upper portion of the driving disc comprises a pair of spaced substantially semi-annular members integral with the driving disc and located in a circular arc concentric with the axis of. rotation of the driving disc and below the lower rim of the eccentric sleeve, said semi-annular members .being arranged to present said oppositely arranged keyway slots, and said dog coupling member is of cup-shaped form with a plain bottom surface resting on the upper surfaces of said substantially semi-annular members.

References Cited in the file of this patent UNITED STATES PATENTS Van Saun Oct. 18, 1927 Brownstein May 9, 1939

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