US20020070601A1

US20020070601A1 - Rock cutting apparatus

Info

Publication number: US20020070601A1
Application number: US09/733,307
Authority: US
Inventors: Ronald Groth; Brian Hoff; Todd Lohnes
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2000-12-08
Filing date: 2000-12-08
Publication date: 2002-06-13
Also published as: DE10156438A1; AU7934401A

Abstract

A rock cutting assembly of the type mounted to a machine capable of exerting downward force includes a plurality of cutters. Each cutter is connected with one of a plurality of separate cylinders for distributing the downward force provided by the machine evenly to each of the cutters.

Description

TECHNICAL FIELD

This invention relates generally to an improved rock cutting assembly for use with a heavy machine capable of providing downward force upon the assembly for breaking and cutting rock.

BACKGROUND ART

A rock cutting assembly is typically mounted to a machine capable of exerting downward force upon the assembly. The assembly includes a cutter wheel to which the downward force is focused. The cutter wheel breaks hard surfaces it contacts from the pressure exerted by the wheel against the hard surface. These surfaces include rocks, concrete, asphalt and any other surface desired to be penetrated. Rock cutters of this type are used to cut trenches in rocky terrain as well as to shave layers off of concrete roadways.

Much of the rock cutter apparatus of the prior art includes only a single cutter wheel capable of cutting only a narrow trench. Occasionally, however, the use of more than one cutter wheel is disclosed. One such example is U.S. Pat. No. 4,175,886 to Moench et al., which discloses an apparatus for cutting asphalt. While the Moench et al. patent is useful for cutting a wide trench into a smooth surface, such as an asphalt roadway, its practicality is limited. Because each of the cutter wheels rotate upon the same shaft, uneven forces will be exerted upon the wheels when cutting a path into a disparate surface. These uneven surfaces can produce forces which induce premature failure of the rock cutting apparatus. In addition, the cutter wheels can be subjected to side forces induced when the mobile machine to which the apparatus is mounted turns. Side forces can cause the premature failure of bearings that support the cutter wheels. A failed bearing immobilizes a cutter wheel requiring the removal of the apparatus from service for repair.

Accordingly, a need exists for a cutter apparatus capable of cutting a wide trench into a disparate surface as well as into a smooth surface. Further, a need exists for a rock cutter apparatus that will evenly distribute the forces generated while cutting rock for preventing damage to the apparatus. The present invention is directed to overcome one or more of the problems as set forth above.

DISCLOSURE OF THE INVENTION

In one aspect of this invention, a rock cutting assembly mounted to a machine capable of exerting downward force includes a plurality of cutters. Each cutter is coupled to a cylinder which generates a downward force upon the cutter. By affixing the cutters to a plurality of cylinders, the forces applied by each cutter are more evenly distributed when cutting a disparate surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the subject invention mounted to a heavy duty machine. [0006]
FIG. 2 is a top perspective view of the subject invention showing the cylinder pins. [0007]
FIG. 3 is a side view of the subject invention. [0008]
FIG. 4 is a sectional view of the subject invention along line IV-IV of FIG. 3.[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIG. 1, a rock cutting assembly is shown generally at [0010] 10 mounted to a machine 12 capable of exerting downward force upon the assembly 10. The assembly 10 includes a plurality of cutters 14 for cutting rock, concrete, or other hard surfaces. In the preferred embodiment, the assembly 10 includes at least two cutters 14, but can include four, six, or more. FIG. 1 shows an assembly 10 having four cutters 14. Typically, the number of cutters 14 used is inversely proportional to the hardness of the cutting surface. For example, a concrete surface with 3,000 psi compressive strength may optimally allow six or more cutters 14 for breaking the surface. However, a natural rock with up to 30,000 psi compressive strength may permit a maximum of two cutters 14. It is understood by those of skill in the art of rock breaking that pressure on a rock from a cutter 14 increases as surface area of contact between the cutter(s) 14 and the rock decreases. Therefore, an assembly 10 having only two cutters 14 will produce greater pressure upon a rock than an assembly 10 having four cutters 14 of similar size.
The [0011] assembly 10 includes a plurality of cylinders 16. Each of the cylinders 16 supports at least one of the cutters 14. In the preferred embodiment, the cylinders 16 take the form of a hydraulic strut for applying downward force upon the cutters 14. The cylinders 16 evenly distribute the downward force generated by the machine 12, providing operational benefits that will be discussed further hereinbelow.
As best shown in FIG. 2, an [0012] assembly frame 18 includes a plurality of cylinder pins 20 affixed thereto for pivotally supporting the cylinders 16. Each of the cylinder pins 20 pivotally support one of the cylinders 16 for allowing the cylinder 16 to pivot in a substantially vertical plane.
The [0013] assembly frame 18 is preferably pivotally affixed to a caster 22 for allowing the assembly frame 18 to pivot in a substantially horizontal plane. The caster 22 reduces side forces on the cutters 14 specifically, and on the assembly 10 generally, when the machine 12 turns by allowing the assembly 10 to pivot. Thus, the utility life of the cutters 14 is extended by the introduction of the caster 22 to the assembly 10.
Each of the [0014] cutters 14 includes a cutter wheel 24. In the preferred embodiment, the cutter wheel 24 comprises hardened steel. However, as required, cutter wheels 24 having carbide inserts or other durability mechanisms may be used. The cutter wheel 24 rotates upon a bearing (not shown) as is commonly practiced in the art of stone breaking. Frequently, the bearings fail when subjected to high side forces Thus, the caster 22, by reducing the side forces on the cutter wheel 24 increases the life of the bearing.
Each of the [0015] cutters 14 includes a cutter frame 26 supporting the cutter wheel 24. The cutter frame 26 comprises a horizontal bar 28 having a pair of brackets 30 extending down therefrom. The cutter wheel 24, disposed on a bearing between the brackets 30, is driven to rotate by friction forces from the rock surface as the assembly 10 is advanced. Through rotation, erosion of the cutter wheel 24 and the stress upon the assembly 10 from friction forces are significantly reduced.
A plurality of [0016] support arm pairs 32 supports each cutter frames 26, as illustrated in FIG. 4. Each of the support arm pairs 32 has one or more cutter frames 26 fixedly attached therebetween. Each of the support arm pairs 32 is pivotally attached to the assembly frame 18 and at an opposite end a cutter frame 26. As best shown in FIG. 3, the pivotal attachment of the support arms to the assembly frame 18 allows each cutter 14 to move in a vertical direction independent of the assembly frame 18, the other cutters and of the machine 12 while still providing latitudinal support to the cutter 14.
The [0017] support arm pairs 32 are arranged having each succeeding support arm pair disposed between each preceding support arm pair. As best represented in FIG. 4, the distance between the support arms decreases for each succeeding support arm pair. For an assembly 10 having at least a first support arm pair 34, and a second support arm pair 36, the first pair 34 is disposed between the second pair 36. For an assembly 10 having a third pair 38 and a fourth pair 40 of support arms, the second pair 36 is disposed between the third pair 38, and the third pair 38 is disposed between the fourth pair 40.
Each of the support arm pairs [0018] 32 pivot on a same support arm pin 42 disposed within the assembly frame 18 proximate the caster 22. Thus, the first, second, third, and fourth support arm pairs 34, 36, 38, 40 include an identical pivot axis 43 on the assembly frame 18.
Each of the support arm pairs [0019] 32 pivot independently of the other support arm pairs 32. For example, the first support arm pair 34 pivots independently of the second, third and fourth support arm pairs 36, 38, 40. Further, the second support arm pair 36 pivots independently of the first, third, and fourth support arm pairs 34, 38, 40. This concept provides for the even distribution of rock breaking forces between the cutters 14.
Each of the [0020] cylinders 16 are in fluid communication with a hydraulic circuit 44. The hydraulic circuit 44 provides pressurized fluid to each cylinder 16 for distributing the downward force to the cutters 14. A fluid accumulator 46 is affixed to the assembly frame 18 as shown in FIGS. 1 and 3 for supplying continuous pressure to each of the cylinders 16. In the preferred embodiment, the hydraulic pressure is produced from a fluid pump (not shown) utilized by the machine 12 for also providing fluid pressure to the machine 12 components. However, a fluid pump designated to the cylinders 16 only may also be used.
Because each of the [0021] cutters 14 is affixed to a separate cylinder 16, the rock breaking forces can be evenly distributed between the cutters 14. This is most important when breaking rocks embedded in a disparate surface as would be expected when cutting undisturbed rock beds, such as along a river bank. By evenly distributing the forces between several cutters 14, the lives of the individual cutters 14 are extended. Further, stresses transferred through the assembly 10 are more evenly distributed, reducing the potential for failures resulting from stress fractures in the assembly 10.
The [0022] cutters 14 are arranged in a sequential pattern oriented longitudinally with respect to the machine 12. Thus, the first cutter 14 will contact a rock initially, followed sequentially by the second, third and fourth cutters 14. Each of the cutter wheels 24 is arranged in an offset spatial relationship which allows altering the spacing between the path of each cutter 14. Therefore, although the cutters 14 are arranged in a sequential pattern, the overall width of the cutter path can be modified by the varying the spacing and number of cutters 14 included with the assembly 10.
Of course, various modifications of this invention would come within the scope of the invention. Although the illustrated embodiment includes an [0023] assembly 10 having a single cylinder 16 supporting each of the plurality of cutters 14, the invention includes within its scope pairing or otherwise grouping multiple cutters on each of a plurality of cylinders. Much of the benefit of the disclosed embodiment can still be realized by providing a force distribution mechanism according to the present invention which prevents the entire downward force from being transmitted through a single cutting wheel.
Additionally, the use of a [0024] caster 22 for pivotally attaching the assembly 10 to a machine 12 reduces side forces on the cutters 14 known to produce premature failure of the cutter wheels 24.

INDUSTRIAL APPLICABILITY

The rock breaking assembly of the present invention provides significant benefits to heavy duty excavation equipment utilized specifically for cracking rock and other hard surfaces, such as concrete or asphalt. The improvements over the prior art, which were discussed above, extend the working life of the rock breaking equipment by evenly distributing the forces associated with breaking rock over several rock cutting wheels. Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims. [0025]

Claims

1. A rock cutting assembly of the type mounted to a machine capable of exerting downward force, said assembly comprising:

a plurality of cutters;

a plurality of cylinders, each of said cylinders supporting at least one of said cutters;

wherein each of said cylinders comprise a hydraulic cylinder for distributing the downward force exerted from the machine.

2. The assembly of claim 1, further including:

an assembly frame pivotally supporting each of said cylinders; and

a caster pivotally affixing said assembly frame to the machine for allowing said assembly to pivot in a substantially horizontal plane.

3. An assembly as set forth in claim 2 wherein said assembly frame includes a plurality of pins affixed thereto for pivotally attaching said cylinders to said frame and allowing the cylinder to pivot in a substantially vertical plane.

4. An assembly as set forth in claim 1, wherein each of said cutters includes a cutter wheel.

5. An assembly as set forth in claim 6, wherein each of said cutters includes a cutter frame for pivotally supporting said cutter wheel.

6. An assembly as set forth in claim 5, wherein said assembly includes a plurality of support arm pairs, each of said support arm pairs having one of said cutter frames fixedly attached therebetween.

7. An assembly as set forth in claim 6, wherein each of said support arm pairs is pivotally attached to said assembly frame at an opposite end thereof from said cutter frames.

8. An assembly as set forth in claim 6, wherein said plurality of support arm pairs include at least first pair and a second pair, said first pair disposed between said second pair.

9. An assembly as set forth in claim 8, wherein said first support arm pair and said second support arm pair include an identical pivot axis.

10. An assembly as set forth in claim 9, wherein said first support arm pair pivots independently of said second support arm pair.

11. An assembly as set forth in claim 1, wherein each of said cylinders is in communication with a hydraulic fluid circuit, said hydraulic fluid circuit supplying hydraulic pressure evenly to each said cylinder.

12. An assembly as set forth in claim 1, wherein said plurality of cutters is arranged in a sequential pattern oriented longitudinally with the machine cutting path.

13. An assembly as set forth in claim 12, wherein each of said cutter wheels is arranged in an offset spatial relationship for altering the distance between the cutter paths.

14. An assembly as set forth in claim 1, wherein said assembly includes a single cylinder independently supporting each of said plurality of cutters.

15. A rock cutting assembly comprising:

a plurality of cutters;

a plurality of cylinders, each supporting at least one of said cutters;

an assembly frame supporting said cylinders; and

said cylinders being in communication with a hydraulic circuit for providing downward force to said cutters.

16. An assembly as set forth in claim 15, further including:

a caster pivotally supporting said assembly frame allowing said assembly frame to pivot in a substantially horizontal plane.

17. An assembly as set forth in claim 15, wherein said at least one cutter includes a cutter wheel.

18. An assembly as set forth in claim 16, wherein said assembly includes at least one support arm pair, said at least one support arm pair having at least one of said cutters fixedly attached therebetween.

19. An assembly as set forth in claim 18, wherein said at least one support arm pair is pivotally attached to said assembly frame.

20. An assembly as set forth in claim 19, wherein said at least one support arm pair is disposed between a second support arm pair.

21. An assembly as set forth in claim 20, wherein said first support arm pair and said second support arm pair include a common pivot axis.

22. An assembly as set forth in claim 15, wherein said cutters are arranged in an offset spatial relationship along a longitudinal cutting path.