US3612611A

US3612611A - Rotary cutter assembly for a pavement grooving machine

Info

Publication number: US3612611A
Application number: US29107A
Authority: US
Inventors: Stafford M Ellis
Original assignee: CONCUT Inc
Current assignee: CONCUT Inc
Priority date: 1970-04-16
Filing date: 1970-04-16
Publication date: 1971-10-12
Anticipated expiration: 1988-10-12
Also published as: DE2151190A1; AU3344671A

Abstract

A rotary cutter head designed for use with tractionally driven pavement grooving machines. A large multiplicity of slightly spaced, radially disposed cutter disks having abrasive peripheries are clamped together by through bolts and mounted on a rotary tubular sleeve which is supported at its end on a fixed central supporting shaft by means of roller bearings. The assembly is driven by a pair of pulleys carried at the opposite ends of the sleeve and torque is applied from the pulleys to the sleeve through the medium of the through bolts which project through both pulleys, as well as through all of the cutter disks.

Description

Assignee United States Patent Stafford M. Ellis Kent, England 391192? Apr. 16, 1970 Oct. 12, 1971 Concut, Inc. Toledo, Ohio Inventor Appl. No. Filed Patented ROTARY CU'I'IER ASSEMBLY FOR A PAVEMENT GROOVING MACHINE l 1 Claims, 5 Drawing Figs.

[56] References Cited UNITED STATES PATENTS 3,376,673 4/1968 Metzger et al. 229/89 Primary Examiner-Ernest R. Purser Attorney-Norman H. Gerlach ABSTRACT: A rotary cutter head designed for use with tractionally driven pavement grooving machines. A large multiplicity of slightly spaced, radially disposed cutter disks having abrasive peripheries are clamped together by through bolts and mounted on a rotary tubular sleeve which is supported at its end on a fixed central supporting shaft by means of roller bearings. The assembly is driven by a pair of pulleys carried at the opposite ends of the sleeve and torque is applied from the pulleys to the sleeve through the medium of the through bolts which project through both pulleys, as well as through all of the cutter disks.

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I'll-rill 5 Ow n PATENTEDnm 12 1911 INVENTOR STAFFORD M ELL/8 ROTARY CUTTER ASSEMBLY FOR A PAVEMENT GRoovrNc MACHINE The improved rotary cutter assembly comprising the present invention is designed primarily for use in connection with a tractional or vehicular concrete pavement grooving machine of the type which is employed for creating antiskid safety grooves in either concrete highways at strategic locations such as at curves, overpasses and the like or in airport concrete runways. Exemplary of this type of machine is U.S. Pat. No. 3,269,775, granted on Aug. 30, 1966. The invention is not necessarily limited to use in connection with a machine whose primary function is to cut constant-depth safety grooves in concrete and the principles of the invention may, with or without modification as required, be employed in connection with pavement levelling machines of the type which is commonly referred to as a bump cutter. Exemplary of such a machine are U.S. Pat. No. 3,007,687, granted on Nov. 7, 1961 and the U.S. Pat. No. 3,195,957, granted on July 20, 1965. Irrespective, however, of the particular use to which the invention may be put, the essential features thereof are at all times preserved.

The invention is concerned primarily with an improved rotary cutting assembly which, without departing from the principles of the invention, may be constructed for use either to cut constant-depth safetygrooves in a pavement or to level the pavement. In general, such a cutting assembly, as well as that of the present invention, embodies a rotary mandrel having mounted thereon in axially-spaced relationship a multiplicity of disklike cutters, such cutters having abrasive segments on the peripheries thereof being comprised of individual metallic matrices containingcrushed orfragmented diamonds or other abrasive particles, and serving in connection with the intended use of the assembly to cut parallel groovesin the pavement. The axial spacing of the cutters is determined by the nature of the operation to be performed on the pavement. Where constant-depth skid-reducing or safety grooves are desired, the spacing between the cutters is'relatively wide, whereas when pavement levelling is resorted to, the spacing between cutters is relatively close. In either event, the cutters are maintained in their spaced relation by spacer members which are interposed between adjacent cutters. In one type of rotary cutter assembly, these spacer members are in the'form of annular or ring-shaped spacer rings which encompass the mandrel of the assembly and are concentric therewith while a series of circumferentially spaced clamping bolts project through the entire series of cutters and spacer rings and clamp them all together in an axial direction. In another type ofrotary cutter assembly, the spacer members are in the form of individual washers which are interposed between adjacent cutters and surround the clamping bolts. With all types of rotary cutter assemblies, a coolant (preferably water) is delivered to the outer peripheries of the cutters, usually by externally positioned spraying devices, but sometimes by internal feeding of the coolant through a hollowcentral mandrel.

As evidenced by U.S. Pat. No. 3,376,673, granted on Apr. 9, 1968, it has heretofore been the practice to journal the rotary mandrel of a rotary cutter assembly in bearings at the opposite ends thereof and to effect rotation of the mandrel and its cutters by providing an overhanging multiple groove pulley on one end of the mandrel or on an extensionon one end of the mandrel, such pulley being disposed outwards of the adjacent bearing. Such an arrangement has not proven altogether satisfactory inasmuch as the tremendous frictional resistance which is offered to the cutters as a group places excessive torque on the mandrel in the region thereof between the pulley and the adjacent group of cutters thereby resulting in frequent rupture of the mandrel in such region. Additionally, due to exposure of the bearings for the mandrel to the products of abrasion, such bearings are possessed of a relative ly short life. Finally, the relatively small diameter mandrel tends to flex during operation of the assembly due to side loads which may be imposed thereon by reason of irregularities or rises in the pavement undergoing treatment so that the .bolts, instead of being'mounted directly on a central rotatable mandrel, are mounted on a rotary mounting sleeve which, in turn, is rotatable on a centrally disposed fixed nonrotatable shaft by means of internal bearings which are interposed between the mounting sleeve and the nonrotatable shaft near the ends of the sleeves, the mounting sleeve being driven by means of a pair of multiple groove pulleys at the ends of the sleeve. By such an arrangement, an overhanging pulley is avoided, the bearings are concealed, and thus,.protected from water and the products of abrasion, and torque is applied to the cutter bluster from both ends thereof.

A further feature of the improved rotary cutter assembly constituting the present invention resides in the provision of a centralspacer member which is affixed to the mounting sleeve and divides the cutter cluster into two parts, one on each side of the fixed spacer member. An advantage of this feature residesin the fact that in assembling the cutter cluster, the cutter. blades and the washerlike spacer members can be loaded on the mounting sleeve from both ends, while functionally the central fixed'spacer member constitutes, inefiect, a central-torque-transmitting drive for the cutter cluster, in addition to the two end drives therefor. I

The primary object of. the invention is to provide a rotary cutter assembly which is characterized by high efficiency and low cost of production and is an improvement upon, and eliminates the various and sundry disadvantages of, previously designed rotary cutter assemblies including that of aforementioned U.S. Pat. No. 3,376,673. Other objects of the invention will be noted'from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set'forth and are more particularly defined by being shown operatively supported in end frame members which constitute a part of the pavement grooving machine with which the cutter assembly is adapted to be associated;

FIG. 2 is an enlarged, fragmentary transverse sectional view taken on the line 22 of FIG. 1; I

FIG. 3 is an enlarged, fragmentary, longitudinal, sectionalview of the assembly;

FIG. 4' is an enlarged, fragmentary, transverse sectional view taken on the line 4-4 of FIG. 3; and

FIG. 5 is an enlarged, fragmentary sectional view of one of the cutters of the assembly.

Referring now to the drawings in detail, and in particular to FIGS. 1 and 2, the rotary cutter assembly of the present invention is designated in its entirety by the reference numeral 10 and is shown as being operatively mounted on the frame of a pavement grooving machine, the frame being represented by two laterally spaced-apart frame members 12 which constitute the sole support for the assembly.

The cutter assembly 10 involves in its general organization a frxedcentral supporting shaft 14 (see FIG. 3) which extends between the two frame members 12 and is secured thereto at its ends in a manner that will .be described presently. The supporting shaft 14 is preferably formed of steel and the opposite end regions thereof are of reduced stepped configuration, the step arrangement at each end of the shaft being the same so that a description of one end region of the shaft will suffice for the other. Considering the right-hand reduced stepped end arrangement of the shaft 12 as viewed in FIG. 3, first, second and third step reductions are provided, these reductions establishing a first shaft surface area 16, a second shaft surface area 18, and a third or outer shaft surface area 20. The outer shaft surface area 20 projects into a circular hole 22 in the adjacent frame member 12 and is secured therein by means of a stud 24 which is threadedly received in a socket 26 in the end of the shaft. Said stud has mounted thereon a nut 25 which bears against a split lock washer 28, the latter in turn bearing against a fiat washer 30.

Surrounding the fixed supporting shaft 14 and concentric therewith is a rotatable cutter mounting drive sleeve 32, the axial extent of which is slightly less than that of the supporting shaft 14. Interposed between the mounting drive sleeve 32 and the supporting shaft 14 at each end of the cutter assembly is a roller bearing and seal arrangement, the two arrangements being substantially identical so that a description of one of them will suflice for them both. Each such roller bearing and seal arrangement includes a roller bearing assembly 40 having inner race parts 42 which seat on the reduced shaft area 18, and, in addition, outer race parts 44 which seat in a recessed counterbore 46 in the adjacent end of the mounting drive sleeve 32. The roller bearing assembly 40 is straddled by a pair of labyrinth-type sealing rings including an inner ring 48 which cooperates with the first shaft surface area 16 and an outer ring 50 which cooperates with the second shaft surface area 18. The inner sealing ring 48 is confined between an annular shoulder 52 at the inner end of the counterbore 46 and the outer race parts 44 of the bearing assembly 40. The outer sealing ring 50 is held in place against the adjacent end or rim of the mounting drive sleeve 32 by clamping bolts 54 the inner ends of which extend into threaded sockets in the adjacent end of the sleeve 32. The roller bearing assembly 40 is confined between the outer sealing ring 50 and an annular shoulder 55 which exists between the

shaft areas

16 and 18.

Means are provided for applying torque to both end regions of the cutter mounting drive sleeve 32 and, accordingly, two multiple groove pulleys 56 are disposed on the opposite end regions of the sleeve and a driving connection is provided between each of these pulleys and the sleeve, as will become apparent presently.

Telescopically received over the cutter mounting drive sleeve 32 are alternately arranged disklike cutters 60 and spacer rings 62. As shown in FIG. 1, there is a multiplicity or large number of the cutters and the spacer rings. Each cutter is in the form of a circular steel disk 63 (see FIGS. 2, 4 and 5) which has a central mounting hole 64 therein (see FIG. 3) and is provided with a series of radial notches 66 in the periphery thereof, the notches being equally and circumferentially spaced and serving to divide the peripheral region of the disk 63 into intervening sections 68. Each section 68 has affixed thereto by a silver soldering or similar operation an abrasive or cutter segment 70 which preferably is in the form of an arcuate sintered metal matrix within which there is dispersed substantially uniformly a quantity of fragmented diamonds or other abrasive material. Each cutter segment 70 is preferably coextensive with the arcuate extent of its associated section 68 and the side portions thereof overhang the opposite side edges of the disk as clearly shown in FIG. 5 and as is well known in the art of constructing peripheral diamond saw blades. The various notches 66 are provided for the purpose of isolating the heat which is applied to the periphery of the disk 63 during the soldering operation and preventing the consequent thermal expansion from causing buckling of the disk.

Each disklike cutter 60 have formed therein an annular series of holes 72 (see FIGS. 2, 3 and 5) which, preferably, are four in number. These holes register with similar hole 74 (see FIGS. 3 and 4) in the spacer rings 62. Clamping bolts 76 project through the registering holes 72 and 74 and also project through aligned bores 78 in a pair of relatively wide spacer members 80, as well as through aligned bores 82 in the two pulleys 56. The clamping bolts 76 are provided with nuts 84 at the opposite ends thereof, these nuts bearing against the outer end surfaces of the pulleys 56. The spacer members are constrained to rotate in unison with the mounting drive sleeve 32 by means of keys 86 (see FIG. 4) which are secured by radially extending screws 88 to said mounting drive sleeve. The spacer members 80 thus serve to transmit to the clamping bolts 76 and, consequently, to all of the cutters 60 and the spacer ring 62 the torque which is applied by the mounting drive sleeve 32.

The central portion of the mounting drive sleeve 32 is provided with an external raised rib 90 (see FIG. 3) to which there is welded a central ring-shaped spacer member 92, the latter constituting, in effect, a radial reaction flange and being provided with bores 94 through which the central portions of the clamping bolts 76 project. Said spacer member 92, being fixed with respect to the mounting drive sleeve 32, serves to divide the cutters 60 and their associated spacer rings 62 into two clusters, each of which is compressed between the spacer member 92 and one of the nuts 84 on the clamping bolt. Relatively thin liner rings 96 are interposed between the spacer member 92 and each adjacent cutter 60. The central spacer member 90 not only maintains the various cutters and spacer rings centered on the supporting shaft 14 in a longitudinal direction, but it facilitates cutter loading of the mounting drive sleeve from either end.

In the operation of the herein described rotary cutter assembly 10, it will be understood that as is customary in connection with similar cutter assemblies for the same purpose, the assembly will be mounted adjacent to the rear end of the pavement grooving machine of which it constitutes a part, and also that during the course of any given pavement grooving operation, the rotary cutter assembly will receive its downward thrust from the two frame members 12 so that the assembly bears the weight of substantially one-half the total weight of the pavement grooving machine with which the frame members are associated. It is contemplated that the operator's cab for the machine will be mounted directly above the cutter assembly 10 so that the weight of the operator will also constitute a thrust factor in maintaining a high pressure of the cutters 60 against the pavement. By such an arrangement, the thrust load upon the cutter assembly is borne by the two roller bearing assemblies 40, one at each end of the central fixed supporting shaft 14 so that this shaft is substantially free from forces tending to flex it. Because the cutters 60 are mounted on the mounting drive sleeve 32 instead of on the usual solid central drive spindle, the tremendous twisting torque which frequently caused rupture of the spindle is obviated and such twisting torque as is applied to the mounting drive sleeve 32 is relatively small, especially since the sleeve is driven from both ends thereof. Finally, it is to be noted that the application of torque to the cutter assembly as a whole is practically a peripheral drive in that the torque is applied by the two pulleys 56 to the clamping bolts 76 which are disposed an appreciable radial distance outwardly from the central axis of the cutter assembly. These clamping bolts also render the cutter assembly rigid and cause the cutters to run true so that they will not deviate from the linearly straight grooves which they are intended to cut in the pavement, this being the case because the clamping action which is exerted by the bolts is at points which are spaced radially outwardly from the mounting drive sleeve 32 and close to the diamond impregnated abrasive segment 70. This affords greater support for the abrasive peripheries of the segments and prevents flutter thereof when they are operating in the grooves at high speed.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit or scope of the invention. For example, if desired, the annular spacer rings 62 may be replaced with individual disklike washers which surround the clamping bolts 76, such an arrangement contributing to the absence of sludge accumulation between the cutter disks 63.

Having thus described the invention what I claim as new and desire to secure by letters patent is:

1. A rotary cutter assembly adapted for grooving pavement or the like and comprising an elongated horizontally disposed supporting shaft having means at its opposite ends whereby it may be fixedly secured to a pair of spaced-apart frame members forming parts of a pavement grooving machine, a generally cylindrical rotary cutter mounting drive sleeve encompassing said shaft in coaxial relationship and substantially coextensive therewith, said mounting drive sleeve being wholly supported by said shaft and rotatable thereon, a series of longitudinally spaced, relatively thin, flat, annular disklike cutters encircling said mounting drive sleeve, disposed in radial planes, and slidable axially on said sleeve, spacer members interposed between adjacent cutters and serving to maintain the same in their longitudinally spaced relationship, a series of circumferentially spaced clamping bolts positioned radially outwardly from said mounting drive sleeve, extending through said cutters and spacers and serving to compress the same together and rigidify the cutters, reaction means preventing longitudinal shifting of said cutters and spacers on the mounting drive sleeve, means for applying torque to said mounting drive sleeve to drive the same, and means establishing a driving connection between said mounting drive sleeve and said cutters.

2. A rotary cutter assembly as set forth in claim 1 and wherein said means for applying torque to the mounting drive sleeve comprises a drive pulley mounted on said mounting drive sleeve adjacent to each end thereof.

3. A rotary cutter assembly as set forth in claim 2 and wherein said means establishing a driving connection between the mounting drive sleeve and cutters comprises a key operatively disposed between at least one of said spacers and the sleeve.

4. A rotary cutter assembly as set forth in claim 3 and wherein the reaction means for preventing longitudinal shifting of the cutters and spacers comprises a radial reaction flange on said mounting drive tube through which said clamping bolts project.

5. A rotary cutter assembly as set forth in claim 4 and wherein said reaction flange constitutes one of said spacers and is disposed between a pair of adjacent cutters on the-medial region of the mounting drive sleeve.

6. A rotary cutter assembly as set forth in claim 5 and wherein the clamping bolts project completely through all of the cutters and spacers and also through said drive pulleys.

7. A rotary cutter assembly as set forth in claim 6 and wherein all of said cutters and spacers are disposed between said drive pulleys, and the clamping bolts are provided with nuts on the opposite ends thereof which bear against the outer ends of the drive pulleys.

8. A rotary cutter assembly as set forth in claim 6 and including, additionally, roller bearing assemblies interposed between said mounting drive sleeve and the fixedly secured supporting shaft and positioned adjacent to the opposite ends of the shaft.

9. A rotary cutter assembly as set forth in claim 8 and wherein each of said roller bearing assemblies is disposed substantially entirely within the radial confines of an adjacent drive pulley.

10. A rotary cutter assembly as set forth in claim 9 and including, additionally, pairs of labyrinth-type sealing rings interposed between the mounting drive sleeve and the fixedly secured supporting shaft and straddling the roller bearing assemblies respectively.

11. A cutter assembly as set forth in claim 10 and wherein said fixedly secured supporting shaft is substantially symmetrical with respect to its midpoint and each end thereof is of stepped configuration providing first, second and third reduced shaft surface areas, said first surface area cooperating with one of said labyrinthtype sealing rings, said second surface area cooperating with the adjacent roller bearing assembly in supporting relationship and also with the other labyrinth sealing ring, and the third surface area constituting a pilot post by means of which the adjacent end of the shaft is supported from the adjacent frame member.

Claims

5. A rotary cutter assembly as set forth in claim 4 and wherein said reaction flange constitutes one of said spacers and is disposed between a pair of adjacent cutters on the medial region of the mounting drive sleeve.

11. A cutter assembly as set forth in claim 10 and wherein said fixedly secured supporting shaft is substantially symmetrical with respect to its midpoint and each end thereof is of stepped configuration providing first, second and third reduced shaft surface areas, said first surface area cooperating with one of said labyrinth-type sealing rings, said second surface area cooperating with the adjacent roller bearing assembly in supporting relationship and also with the other labyrinth sealing ring, and the third surface area constituting a pilot post by means of which the adjacent end of the shaft is supported from the adjacent frame member.