US3451721A

US3451721A - Combination slotting and milling tool

Info

Publication number: US3451721A
Application number: US621013A
Authority: US
Inventors: Carle W Highberg; James B Speirs
Original assignee: Engelhard Hanovia Inc
Current assignee: Engelhard Hanovia Inc
Priority date: 1967-03-06
Filing date: 1967-03-06
Publication date: 1969-06-24
Anticipated expiration: 1986-06-24

Description

June 24,1969 c. w. HIGHBERG ET AL COMBINATION SLOITING AND MILLING TOOL m 2 0 TG f NR 0 O E 4. mm 3 men S t W ES h LE S RM AA CJ Y B w 2 2 F 7 6 9 1 G 6 h C F r a M d e l 1 F v AGENT C. 'W. HIGHBERG ET AL COMBINATION SLOTTING AND MILLING TOOL Sheet 3 of 2 June 24, 1969 Filed March a. 1967 DIRECTION OF TRAVEL p CENTER LINE DISTANCE INVENTORS CARLE W. HIGHBERG JAMES B. SPEIRS United States Patent 3,451,721 COMBINATION SLOTTING AND MILLING TOOL Carle W. Highberg, Murray Hill, and James B. Speirs, Paramus, N.J., assignors to Engelhard Hanovia, Inc., Newark, N..I., a corporation of New Jersey Filed Mar. 6, 1967, Ser. No. 621,013 Int. Cl. E21c 25/18 US. Cl. 299-89 2 Claims ABSTRACT OF THE DISCLOSURE The present invention deals with a combination slotting and milling tool for slotting and milling surfaces of refractory materials such as concrete paving, asphalt paving, brick, granite, slate, etc., having a cylindrical spool- BACKGROUND OF THE INVENTION In the marking of concrete paving of highways with reflecting surfaces or lines, e.g., for the purpose of outlining driving lanes, or the like, it has been known to cement or otherwise secure projecting reflecting particles or beads on the surface of a substrate strip material, e.g. metal strip, and to cement the strip to the surface of the highway. Such a reflecting marking means for highways presents a problem in that the reflecting strip material is raised on the surface of the highway and becomes damaged or dislodged especially by snowplows or other heavy vehicles passing thereover. Since, of course, the surface of the highway is not always smooth it does not always conform to the bonding surface of the strip material so that the strip is not always uniformly securely bonded to the roadway.

I order to overcome such disadvantages, it has been thought to recess grooves in the highway surface and to partly recess the reflector bearing strip into the recess grooves. However, grooving the highway a suflicient depth to anchor the strip material therein is an expensive and tedious matter since, in such case, a large quantity of the road material has to be removed by milling to provide grooves of sufficient width and depth to anchor the inlaid strip. The invention contemplates the secure anchoring of a raised reflecting strip on a roadway by a minimum removal of the road material, whereby the strip material is anchored mainly at its opposite longitudinal edges, which are formed to engage a pair of parallel slots cut into the road surface and with the road material, e.g. concrete, between the slots being milled preferably sufficiently only to provide a shallow groove for the smoothening of the road material between the parallel slots to more uniformly engage and mate with the undersurface of the strip material for improved bonding, such as cementing, of the strip to the roadway.

SUMMARY OF THE INVENTION It is herein contemplated to provide a combination slotting and milling tool for slotting and milling refractory surfaces, which comprises the combination of a cylindrical drum having a pattern of spaced abrasive means raised on and about the cylindrical outer surface of the drum, and a pair of laterally spaced cutting discs each being mounted co-axially of the drum at each end of the drum and each being of greater diameter than the drum and having a plurality of abrasive means circumferentially spaced from each other and mounted on the peripheral surfaces of the discs.

THE \DRAWINGS FIGURE 1 is an elevational end view of the combination slotting and milling tool according to the invention,

FIGURE 2 is a cross-sectional view along lines 22 of FIGURE 1,

FIGURE 3 is an isometric view of a component of the tool of the invention,

FIGURE 4 is a fragmentary cross-sectional view of a concrete roadway slotted and milled with the tool of the invention, and

FIGURE 5 is a schematic view of the tool showing concrete removal.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, FIGURES 1-3 illustrate the combination slotting and milling tool of the invention. The tool comprises a cylindrical metal drum 2 having inwardly directed annular flanges 4 and 6 with one at each open end thereof and which may be integral with the drum or welded thereto and which define openings 5 and 7, respectively. The outer surface of the drum is provided circumferentially thereof with a pattern of recesses 8, and a plurality of abrasive inserts 10 are each suitably mounted in one of the recesses as by brazing or welding. The inserts are composite inserts having a metal base 12 with a metal slug 14, for milling purposes, impregnated with abrasive particles and bonded to the metal base 12, as by silver brazing, with the metal base 12 seated in the recess 8. The flanges 4 and 6 are each provided with circumferentially spaced bores "16, e.g. threaded bores formed therethrough and arranged substantially as illustrated by FIGURE 3. l

A pair of centrally apertured cutting wheels or

discs

18 and 20, of greater outer diameter than the drum 2 are each provided with circular central apertures 19 and 21, respectively, preferably coinciding in diameter with the openings 5 and 7, and each disc is mounted one at each end of the drum 2 as illustrated by FIGURE 2. Each cutting disc is provided with circumferentially spaced apertures 22 therethrough arranged to coincide with bores :16 in the flanges 4 and 6. A circular securing plate 24 having a central opening 26 with a short annular shoulder 28 defining the opening 26 and extending outwardly of the plate 24 co-axially of the opening 26 is mounted adjacent the disc 18 with the outer surface of the shoulder inserted in abutment with the walls of opening 5 of flange 4 and the walls of aperture '19 of disc 18 and with the plate in abutment with the outer side of disc 18. The plate 24 is provided with circumferentially spaced bores 30 therethrough arranged to coincide with flange bores 16 and disc apertures 22. Securing means, e.g. screws or bolts 32, are each engaged with a bore 30, aperture 22 and flange bore 16 to secure the plate 24 and disc 18 to drum flange 4.

A substantially cylindrical hub member 34 is mounted in opening 7 and aperture 21 and in abutment with the walls of opening 7 and aperture 21 of disc 6 and a portion 35 of the hub extends into the drum 2. The hub member 34 has a co-axial shaft bore 36 formed therethrough and a flange 38 at one portion thereof with the flange positioned in abutment with disc 20. The flange 38 is provided with bores 40 formed therethrough and arranged to coincide with apertures 22 and bores 16. Securing means, e.g. screws or bolts 42, are each engaged with a bore 40 of flange 38, aperture 22 and bore 16 of drum flange 6 to secure the hub 34 to the drum 2.

Each of the

discs

18 and 20 is provided with a plurality of abrasive means 44 mounted on the peripheral surfaces thereof and circumferentially spaced from each other. The abrasive means 44 are composite bodies having a metal base 46 with a metal slug 48, for cutting purposes, impregnated with abrasive particles bonded to the metal base 46. The abrasive particles may be particles of tungsten-carbide or diamond grit depending on the material to be slotted or milled, preferably, the abrasive means 44, as well as the abrasive means hereinbefore described, comprise a metal slug impregnated with diamond abrasive material.

FIGURE 3 illustrates the advantageous pattern of spaced abrasive means 10 on the surface of drum 2. In order to effect uniform milling of a groove from one side to the other and to economize on the abrasive material, especially when diamond material is employed as the abrasive, the spaced inserts are arranged in a pattern of rows spaced circumferentially of the drum with the inserts of one row A staggered relative to the inserts of another adjacent row B, and the rows being directed at an acute angle from one end of the drum to the other relative to the drum axis. Also, the number and abrasive surface areas of inserts 10 on the drum 2 are preselectively proportioned relative to the cutting members 44 on

discs

18 and 20 so that when both the discs and drum are in contact with the refractory material, e.g. concrete, there will be approximately equal wear of the cutting and milling abrasive means whereby the relative depth of the cuts remain substantially the same throughout the life of the tool. The rows of inserts A and B, etc., on drum 2 are spaced from each other a greater distance than the spacing between abrasive means 44 on

discs

18 and 20. For example, each

disc

18 and 20. For example, each

disc

18 and 20 may be about 8" in diameter with about thirty six abrasive means 44 about its periphery, while the drum 2 may be about 6" to 7 in diameter with about sixteen rows of inserts about its circumference.

Having provided the tool in accordance with the invention, the tool is driven by a motor means (not shown) connected to a shaft threaded at its free end and mounted through hub bore 36 and secured by a bolt 52. Thus, when the shaft 50 is rotated, the entire tool including drum 2 and

discs

18 and 20 are likewise rotated at advantageous speeds for the cutting and milling.

FIGURE 4 illustrates, as a cross-sectional view in the direction of tool motion, one type of laterally spaced slots 54 and 56 and intermediate groove surface 58 formed by the tool. For application to the illustrated slots and groove, the metal insert 60, carrying on .a portion of its surface a layer 62 of reflecting particles or beads has a substantially U-shaped cross section with the

legs

64 and 66 of the U-shaped metal substrate strip engaging and preferably cemented in the slots 54 and 56. The metal insert with its reflecting particles extends a small distance above the road surface when in place, as illustrated by FIGURE 4, and the reflecting surfaces, projecting less than uncovered metal portions of the insert, are readily visible to oncoming motorists without being damaged by impact.

In operation, a conventional concrete diamond sawing machine with the tool rotating was caused to first penetrate the concrete without moving the tool horizontally, the tool next was moved horizontally in the direction of automotive traflic flow and then finally was raised from the concrete. Total time for such concrete removal steps was less than a minute.

An example of the preselection of areas of abrasive members on disc and drum for approximately equal wear of the tool designed in accordance with this invention for slotting and milling concrete is given below.

EXAMPLE Grinding abrasive elements were attached to the discs or saws and the drum with 4;" thick hot-pressed diamonds in a matrix chiefly of iron, e.g. steel with minor amounts of carbon and manganese on a A" thick hotpressed backing chiefly of iron. Surface dimensions for each abrasive elements were /2" x A". In accordance with the saw and drum dimension given below, 36 such abrasive elements were used on each saw and 72 such abrasive elements were used on the drum.

Cuts in the direction of automotive traffic using a tool in accordance with FIGURES 1-4 were made for a A" full depth removal of concrete with each saw blade for a center line to center line full depth distance of 5" as shown in FIGURE 5. FIGURE 5 is a schematic end view of the tool showing the initial application of the tool at the left in broken lines for the beginning of the cutting and milling and showing at the right an end of the tool in solid line at the completion of the cutting and milling for the concrete removal to inlay a reflector. Full depth concrete removal takes place between the center lines C and D and additional segment volume removals occur as indicated at E and F in FIGURE 5. Two conventional concrete saws of 4 radius were used for the slotting, the abrasive material being 2040 grit size diamonds in concentration of 30 carats per cubic inch embedded in the matrix to a surface depth of /8". The same size and concentration of diamonds with the same matrix was used for the .abrasive on the drum surface. The drum had a radius of 3%" to the grinding surfaces in order to remove /8" of concrete, full depth removal of the concrete with the drum also taking place for a distance of 5".

The volume of concrete to be removed by the described tool in inlaying each reflector was calculated .as follows:

By each saw (1) Full depth cuts:

depth x A" Width X 5" length=0.938 in. (2) Segment volume before and after full depth cuts:

2.38 in? segment area x A width=0.595 in.

By the drum 1) Full depth cuts:

4; depth x l -W with x 5 length:0.938 in. 2) Segment volume before and after full depth cuts:

0.18 in. segment area x 4% width=0.82 in.

Accordingly, the volume to be removed by drum cutting was 3.67 in? and by cutting with each saw was 1.53 in. or a ratio of 2.4: l. A tool was constructed using a ratio of drum cutting surface to saw cutting surface of 2:1, taking into account that plunging entry of saws is expected to cause additional saw wear.

Various modifications of the invention are contemplated within the scope of the appended claims.

What is claimed is:

1. A combination slotting and milling tool comprising a cylindrical drum, a plurality of abrasive means mounted on and extending outwardly of the peripheral surface of the drum in spaced relationship with each other, said spaced abrasive means being arranged in rows spaced for each other circumferentially of the drum, a pair of circular disc members having an outer diameter greater than the outer diameter of the drum each mounted on one end of the drum coaxially thereof, a plurality of abrasive means mounted on the peripheral surface of each disc and spaced from each other circumferentially of the disc, the said rows of abrasive means being spaced from each other a greater distance than the spacing between the abrasive means mounted on said discs, and said rows each being directed from one end of the drum to the other at an acute angle relative to the drum axis.

2. A combination slotting and milling tool according to claim 1, wherein such abrasive means comprises a metal slug impregnated with diamond particles.

(References on following page) 5 References Cited UNITED STATES PATENTS 1 ,965,384- 7/1934 Legge 125-5 2,000,7-72 5/1935 McGill 51--206.4 2,032,362 3/1936 Herman 51-2064 5 3,162,187 12/ 1964- Christensen 125-15 6 3,324,603 6/1967 Niemiec 51-206.4 3,338,230 8/1967 Lindblad 125-15 HAROLD D. WHILEHEAD, Primary Examiner.

US. Cl. X.R. 51-181, 206; 125-5