US3695723A

US3695723A - Abrading tool

Info

Publication number: US3695723A
Application number: US58925A
Authority: US
Inventors: John F Kita; James W Heaton
Original assignee: Kennametal Inc
Current assignee: Kennametal Inc
Priority date: 1970-07-28
Filing date: 1970-07-28
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03

Abstract

The specification discloses an abrading tool in which rings having hard metallic carbide inserts therein are loosely mounted in side by side relation on a shaft and which shaft, in turn, is mounted in a reel together with other like shafts so that as the reel rotates on an axis parallel to the shafts, the abrading elements will be brought into engagement with a surface to be abraded and the carbide inserts will effect the abrading.

Description

D Unlted States Patent 1 3,695,723 Kita et al. [451 Oct. 3, 1972 ABRADING TOOL 3,266,846 8/1966 Luksch et al. ..299/86 X [721 lnvemrs= gg gg g g Hem", FOREIGN PATENTS OR APPLICATIONS [73] Assignee Kc eta] Inc g g Pa 1,188,305 4/1970 Great Britain ..175/373 [22] Filed: July 28, 1970 Primary Examiner-Ernest R. Purser pp No 58 925 Attorney-Melvin A. Crosby [57] ABSTRACT Y The specification discloses an abrading tool in which 58] Fieid 175/33/3 rings having hard metallic carbide inserts therein are 1 loosely mounted 1n side by slde relation on a shaft and which shaft, in turn, is mounted in a reel together with other like shafts so that as the reel rotates on an axis [56] References cted parallel to the shafts, the abrading elements will be UNITED STATES PATENTS brought into eng agement with a surface to be abraded 2 121 02 938 gore 5/37 and the carblde lnserts wlll effect the abradlng. 2:687:875 8/1954 Morlan et al. 175/374 7 Claim, 6 Drawing figures PATENTEDnms m2 INVENTORS JAMES W. HEATON JOHN F. KITA Maw ABRADING TOOL The present invention is concerned with an abrading tool or wheel and especially with abrading elements for use with such tools.

The abrading of surfaces such as concrete roadways and the like is known and is an operation which is carried out to remove unsound material from the surface to prepare it for receiving a layer of new surface material or in some cases, to remove substantially the entirety of the material in a certain region.

Power operated abrading devices for carrying out such abrading operations are also known and, in general, comprise wheels or holders rotatable on a work axis and carrying in circumferentially spaced relation individual abrading elements. The abrading elements heretofore have generally been in the form of hard steel star wheels which are presented radially to the surface to be abraded as the holder rotates and carry out a picking action on the surface.

Relatively soft surfaces can be abraded relatively rapidly with devices of the nature described but hard materials such as concrete, abraded somewhat more slowly and, in particular, are so hard and abrasive that steel star wheels will wear away extremely rapidly thus requiring frequent shutdown of the abrading machine and replacement of the star wheels.

With the foregoing in mind, a primary objective of the present invention is the provision of an abrading machine of the nature referred to having abrading elements mounted thereon in which the material of the abrading elements that comes in contact with the surface being abraded is a cemented hard metallic carbide composition. I

Another object of the present invention is the provision of an abrading element embodying cemented carbide which can be utilized in existing abrading machines in place of the presently used steel star wheels.

Still another object of the present invention is the provision of an abrading element of the nature referred to for use in surface abrading machines in which the abrading element can be made relatively simply but which has a useful life several times as long as the life of a steel star wheel.

It is also an object of the present invention to provide an abrading element of the nature referred to in which the cemented carbide which comes in contact with the material to be abraded is so disposed and Supported in the body of the abrading element as to prevent easy fracturing and crumbling of the carbide material.

The foregoing objects as well as still other objects and advantages of the present invention will become more apparent upon reference to the following detailed specification taken in connection with the accompanying drawings in which:

FIG. 1 is a schematic perspective view partly broken away showing an abrading wheel enclosed within a dust hood and having abrading elements thereon according to the present invention;

FIG. 2 is a transverse section through the abrading wheel schematically illustrating the construction thereof and the placement of the abrading elements thereon;

FIG. 3 is a view drawn at enlarged scale looking at one of the abrading elements from the side and with the abrading element partly broken away to show the manner in which the carbide inserts are mounted therein;

FIG. 4 is a sectional view indicated by line IV-IV on FIG. 3 and showing the relative placement of adjacent abrading elements on a support shaft therefor;

FIG. 5 is a fragmentary view showing another type of abrading element constructed according to the present invention; and

FIG. 6 is a fragmentary view showing a portion of an abrading wheel of modified construction.

BRIEF SUMMARY OF THE INVENTION The present invention is concerned with the abrading of surfaces by means of a rotary abrading tool or wheel having abrading elements mounted thereon. Such wheels are, in general, known but heretofore have employed hard steel star wheels as the abrading elements which are mounted on support shafts provided therefor about the periphery of the abrading wheel with freedom of radial movement of the star wheels so that as the abrading wheel is rotated and brought into engagement with a surface to be abraded, the star wheels will impact against a surface and carry out the abrading operation.

The present invention is especially concerned with the provision of an improved abrading element to replace the aforementioned star wheels in which each element comprises a steel support ring having distributed circumferentially thereof a plurality of hard inserts, preferably of a cemented hard metal carbide, such as tungsten carbide.

Advantageously, the hard inserts are relatively short rod-like members and are press fitted into radial bores provided therefor in the periphery of the ring.

DETAILED DESCRIPTION Referring to the drawings more in detail, in FIG. 1, an abrading wheel, generally indicated at 10, is rotatable on the axis of a support shaft 12 and is contained within a shield or housing 14 from which a dust collecting duct 16 leads upwardly.

The wheel 10, schematically illustrated in FIG. 2, carries in circumferentially spaced relation, and near the outer periphery thereof, a plurality of axially extending support shafts 18. Mounted on the support shafts in side by side axially spaced relation are the abrading elements 20 constructed according to the present invention.

The abrading elements are shown more in detail in FIGS. 3 and 4 wherein it will be seen that each comprises a steel ring part 22 having a central hole 24 with substantial radial clearance from the support shaft 26. Each ring part 22 is provided with a plurality of radial bores 28 and press fitted into each of the radial bores is a rod-like hard wear resistant insert 30, preferably of a cemented hard metal carbide such as tungsten carbide and advantageously having a domed outer end 32. The particular number of inserts can vary and, purely by way of example, 12 inserts are shown in each wheel. The inserts may be aligned in the circumferential direction or may be staggered.

As will be seen in FIG. 4, adjacent ones of the abrading elements 20 may be supported in axially spaced relation on support shaft 26 by the interposition therebetween of spacer washers 34. Alternatively, each ring may be provided with an integral hub portion as indicated at 35 in FIG. 5 and which will hold the abrading elements in axially spaced relation without the use of any washers therebetween.

In practice the shafts 18 are readily detachable from the wheel as by means of quick release supporting devices indicated by the dotted outlines 36 in FIG. 2.

Another type of abrading wheel has a cast body with upstanding hubs 38 as shown in FIG. 6 with the hubs axially spaced and disposed between each adjacent pair of the hubs 38 are abrading elements 40 according to the present invention. In the arrangement of FIG. 6, support shafts 42 are mounted in the abrading wheel body and can be removed therefrom in the axial direction to permit replacement of worn abrading elements. 7

Due to the radial clearance between the bore in each abrading element and the supporting shaft therefor, the abrading elements can move radially a total distance of up to, say, one-half the shaft diameter and will thereby be caused to impact against the surface being abraded as the abrading wheel 10 is driven in rotation.

The abrading elements according to the present invention outlast the conventional star wheels by substantial periods of time thereby permitting the machine on which the wheel 10 is mounted to run for substantially longer periods of time between shutdownsJ-Iard materials such as concrete can be abraded by the use of d an abrading wheel according to the present invention and all defective concrete removed leaving only sound material for receiving any type of overlaying material and, in particular, leaving a somewhat roughened surface that provides a good tooth for holding the overlay material.

A concrete area can be completely abraded away by the use of the device of the present invention if so desired.

Concrete is not the only material that can be treated by wheels having abrading elements according to the present invention but has been referred to above because it represents one of the most difficult materials to work. Such other uses of the abrading element as may occur to those skilled in the art are intended to be included within the purview of the present invention, such other uses, as well as the abrading of concrete surfaces coming under the broad heading of surface treatment.

Inasmuch as the abrading elements move radially relative to the supporting shafts therefor, it follows that the abrading elements will also impact against the shafts. For the reason that the abrading elements can wear away rapidly under certain circumstances, it is preferable for the shaft to be somewhat harder than the abrading elements so that the shaft can be used for a prolonged period of time for several sets of the abrading elements.

It has been found practical and satisfactory to form the shaft of steel and to heat treat the shaft to a hardness of about 50 on the Rockwell C scale while the bodies or ring parts of the abrading elements are also made of steel and are heat treated to a hardness of about 45 on the Rockwell C scale. With this heat treatment, the shafts do not wear at an excessive rate of before the shafts must'be replaced.

By the use of the abrasive elements according to the present invention, wherein the hard wear resistant regions presented to the surface being abraded are of limited area, highly efficient removal of unsound formations becomes possible. The removal of unsound concrete, for example, is more efficient when using an abrading element according to the present invention than when using other abrading elements that span greater dimensions of the concrete being treated.

Thus, a more efficient surface treatment is possible with the abrading element of the present invention and, in most cases, in a single pass across deteriorated concrete surfaces, all of the unsound concrete can be removed and a sound surface presented for presenting overlay material, which may be concrete or an asphalt composition or the like.

As mentioned, since all of the unsound concrete is removed, the resulting surface will be somewhat rough and irregular and this provides an excellent tooth for the overlay material to assist in locking it in place.

It will also be appreciated that the rod-like inserts are always confined in the circumferential direction and thus are supported against splitting and fracturing due to the impacts'delivered thereto. The steel of the body of the abrading element will wear away faster than the inserts so that there is always at least a short length of each insert projecting from the periphery of the body of each abrading element.

The abrading elements will remain highly efficient as long as the inserts are not completely worn away and throughout the life of each abrading element the inserts will be supported against fracturing and bending to the work in the most efficient manner, namely, substantially endwise.

Modifications may be made within the purview of the appended claims.

What is claimed is: c

1. In an abrading machine having a generally cylindrical rotor rotatable about a central axis and carrying a plurality of shafts parallel to said axis and spaced cir cumferentially about said rotor near the outer periphery thereof, a plurality of annular ring members mounted on each said shaft to project radially from the outer periphery of said rotor, means on said shafts between adjacent ring members to maintain said adjacent ring members in axially spaced relation, each said ring member being of larger inside diameter than the shaft on which it is mounted to permit limited free radial movement of each said ring member, and each said ring member being provided with a plurality of circumferentially distributed cylindrical sockets extending radially into the outer periphery thereof, hard wear resistant rod-like inserts press fitted into each said socket with each said insert projecting radially from the outer peripheral surface of said ring member a predetermined distance, and domed outer ends on said inserts.

2. An abrading machine according to claim 1, in

which the ring members are flat on the opposite sides thereof and washer means mounted on said shaft between adjacent ones of said ring members comprising said means to maintain said axially spaced relation.

3. An abrading machine according to claim 1, in which the ring members include hub means on at least one side thereof comprising said means to hold adjacent ones of said rings in axially spaced relation.

6. An abrading machine according to claim 5, in which said carbide is tungsten carbide.

7. An abrading machine according to claim 1 in which each said ring member has an inside diameter equal to about one and one-half times the diameter of the shaft on which it is mounted.

Claims

1. In an abrading machine having a generally cylindrical rotor rotatable about a central axis and carrying a plurality of shafts parallel to said axis and spaced circumferentially about said rotor near the outer periphery thereof, a plurality of annular ring members mounted on each said shaft to project radially from the outer periphery of said rotor, means on said shafts between adjacent ring members to maintain said adjacent ring members in axially spaced relation, each said ring member being of larger inside diameter than the shaft on which it is mounted to permit limited free radial movement of each said ring member, and each said ring member being provided with a plurality of circumferentially distributed cylindrical sockets extending radially into the outer periphery thereof, hard wear resistant rod-like inserts press fitted into each said socket with each said insert projecting radially from the outer peripheral surface of said ring member a predetermined distance, and domed outer ends on said inserts.

2. An abrading machine according to claim 1, in which the ring members are flat on the opposite sides thereof and washer means mounted on said shaft between adjacent ones of said ring members comprising said means to maintain said axially spaced relation.

4. An abrading machine according to claim 1, in which said ring members are steel treated to a hardness on the order of about 45 Rockwell, C Scale and said shafts are steel with a hardness on the order of about 50 Rockwell, C Scale.

5. An abrading machine according to claim 1 in which said rod-like inserts are formed of cemented hard metal carbide.