US3686798A

US3686798A - Belt grinding machines and platen therefor

Info

Publication number: US3686798A
Application number: US89680A
Authority: US
Inventors: Charles Copresti
Original assignee: Carborundum Co
Current assignee: CA ACQUISITION Co CHICAGO ILL A CORP OF; Unifrax I LLC
Priority date: 1970-11-16
Filing date: 1970-11-16
Publication date: 1972-08-29
Anticipated expiration: 1989-08-29
Also published as: DE2156536A1; GB1372196A; CA945379A; JPS5621543B1

Abstract

A platen includes a narrow pressure strip of a hard material rigidly mounted on a supporting portion of the platen. The grinding machine utilizing the platen is the type in which work is fed in a direction normal to the movement of the abrasive belt. The platen is rigidly tensioned against the abrasive belt so that narrow pressure portion urges the abrasive belt against a workpiece.

Description

United States Patent CoPresti [1 1 3,686,798 [451 Aug. 29, 1972 [72] inventor: Charles CoPresti, 1064 99th St.,

Niagara Falls, NY. 14304 [73] Assignee: The Carborundnm Company, Niagara Falls, N.Y.

[22] Filed: Nov. 16, 1970 [21] Appl. No.: 89,680

[52] US. Cl. ..51/l38, 51/141, 51/148 [51] Int. Cl ..B24b 21/08, B24b 21/10 [58] Field of Search.....5l/l37, 138,141,103 R, 148

[56] References Cited UNITED STATES PATENTS 1,924,593 8/1933 Binns .51] 103 R 1,978,149 10/1934 Stevenson; ..5l/141 X 2,762,173 9/1956 Bottcher ..5l/ 138 X 2,717,422 9/1955 Rowe... ..51/l41 X 2,651,150 9/1953 Florez...... ..51/138 FOREIGN PATENTS 0R APPLICATIONS 924,256 2/1955 Germany ..5 1 1 38 Primary Examiner-Donald 0. Kelly Attorney-K. W. Brownell ABSTRACT A platen includes a narrow pressure strip of a hard material rigidly mounted on a supporting portion of the platen. The grinding machine utilizing the platen is the type in which work is fed in a direction normal to the movement of the abrasive belt. The platen is rigidly tensioned against the abrasive belt so that narrow pressure portion urges the abrasive belt against a workpiece.

5Claims,4DrawingFigures BACKGROUND OF THE INVENTION In belt sanding and polishing machines of a known type, an endless abrasive belt is trained about a plurality of rollers and a platen is rigidly mounted above the active run of the abrasive belt for urging the belt the purposes for which they were designed, they have not performed satisfactorily under all conditions of operations. In the processing of full-bodied materials, such as bar stock, sheet stock or in the processing of very hard ferrous materials, such as high carbon steel, these platens have caused overheating, even with the flood of coolant, with the result that center areas of the object being ground are often burned and distorted. An additional problem is the accumulation of grinding dust between the belt and the workpiece which makes the belt blunt and ineffective. Furthermore, unless the square or rectangular platen is at a proper angle with respect to the workpiece, so that the leading edge is above the trailing edge, the belt will wear unevenly. Adjusting platens of the prior art is often a time consuming trial and error process.

I-leretofore, platens of the prior art have not been effective in aggressively removing stock to produce a uniform surface while acheiving an even wear of the abrasive belt.

SUMMARY OF THE PRESENT INVENTION It is an object of the present invention to provide a new and improved platen for a belt grinding machine.

It is another object of the present invention to provide a grinding machine with an improved platen which removes stock aggressively without marring the finished surface of the workpiece.

It is yet another object of the present invention to provide a new and improved platen which is simple and strong in construction, effective in prolonging the life of the abrasive belt, and rugged and durable in use.

These and other objects of this invention will become more apparent upon consideration of the following description thereof.

In accordance with the present invention, there is provided a platen for a belt grinding machine comprising a supporting portion and a pressing portion rigidly mounted on said supporting portion, said pressing portion comprising a narrow strip of wear resistant material adapted to extend obliquely across the width of the belt for urging the belt against a workpiece.

Also in accordance with the present invention, there is provided a grinding machine utilizing the aforementioned platen.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l illustrates the platen assembly as employed in.

a grinding machine;

FIG. 2 is a front elevational view of mounting;

FIG. 3 is a side view of the platen; and

FIG. 4 is an end view of the platen of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings in more detail, and particularly to FIG. 1, it can be observed that in a preferred embodiment of this invention the belt grinding machine 11 includes a grinding head 13 mounted on a base 15. Adrive roller 17 is mounted on the grinding head 13 for rotation in suitable bearing means and driven by an electric motor (not shown). Idler roller 19 is horizontally spaced from the drive roller 17 and is mounted for rotation between two spaced arms of yoke member 21 which is mounted on the grinding head 13. Tracking roller 23 is vertically spaced from the drive roller and similarly mounted on yoke member 25. The bight portion of yoke member 25 is connected to one end of a fluid power device or fluid cylinder 27. The other end of the fluid cylinder 27 is connected to arm 29 rigidly mounted on the grinding head I3. Actuation of the fluid cylinder 27 acts to apply tension to an abrasive belt 31 which is trained around rollers l7, l9 and 23.

The grinding-head I3 is positioned above a conveyor 33 so that work 35 is fed into the abrasive belt 31 in a direction normal to the movement of the abrasive belt 31. To permit convenient grinding of workpieces of varying thickness, the distance between the abrasive belt 31 and the conveyor 33 may be selectively varied. It is contemplated that this adjustment may be achieved by various conventional means. For example, the grinding head 13 can be supported for vertical movement by utilizing a pair of split tapered gibs attached to the backside thereof. The gibs slide vertically in square ways in a pair of columns firmly mounted to the base 15 or floor. A screw jack can be used to raise or lower the grinding head 13. In another arrangement for adjusting the grinding machine to accomodate different workpieces, the conveyor may be selectively raised or the platen lowered by screw jacks while the grinding head remains rigidly mounted to supporting members. Since many such arrangementsof grinding head and conveyor are known in the prior art, no illustration or further explanation is believed necessary.

As illustrated in FIG. 1, the conveyor 33 which feeds work 35 in a direction indicated by the arrow is of a conventional type. The conveyor 33 includes a conveyor frame 37 which is provided with rollers 39 journaled for rotation at opposite ends thereof. An endless conveyor belt 4l advances the workpieces beneath the abrasive belt 31. The conveyor belt 41 is driven by any suitable means, such as an electric motor, at a selected speed.

A pair of platen support members 43 which have flat mounting surfaces 45 facing the conveyor belt 41 project outwardly from the grinding head 13. The support members 43 are preferably a pair of angle irons each having one side secured to the grinding head 13 with another side projecting over the conveyor belt 41. A plate 47 is rigidly mounted to the mounting surfaces 45. A plurality of bores 49 in the mounting surfaces 45 are aligned with bores 51 in the backing plate 47. Bolts 53 passing through bores 49 and bores 51 secure the plate 47 to mounting surface 45. The plate 47 is preferably adjusted so as to lie in a plane parallel to the work supporting surface of the conveyor belt 41 by utilizing spacing members 55 around the bolts 53. The spacing members 55 are positioned between the plate 47 and the mounting surface 45.

The platen 57 is rigidly positioned above the conveyor belt 41 and tensioned against the non-abrasive side of the abrasive belt 31. The height of the platen above the conveyor is varied depending upon the amount of stock removal desired or the precise dimension of the workpiece desired.

The platen 57 comprises a supporting portion 59 in the shape of an elongated rectangular bar. The top surface 61 of the supporting portion 59 is rigidly secured to the bottom of plate 47. Preferably bolts 63 pass through holes 65 in the plate 47 and engage threaded holes 67 in the top surface of the supporting portion 59.

According to the principles of the present invention as illustrated in a preferred embodiment, the bar platen 57 comprises a pressing portion 69 which is a narrow strip of wear resistant material extending lengthwise of the platen and projecting downwardly from the bottom surface of the supporting portion 59. Preferably the pressing portion is a strip of uniform width with a bottom surface aligned in a plane substantially parallel to the work conveying surface. Most preferably a single pressing portion of less than about one inch in width is employed so as to achieve an agressive grinding action while minimizing overheating of the work and accumulation of detritus.

The pressing portion 69 is preferably an insert of a hard, dense wear resistant material such as tungsten carbide. As illustrated in FIG. 4, the supporting portion 59 includes a rectangular recess or slot 73 extending lengthwise and positioned in the widthwise center of the bottom surface of the supporting portion 59. A plurality of laterally bored holes 75 are aligned with the slot 73 and extend through one side of the supporting portion 59. Threaded holes 77 in the insert are aligned with holes 75. Bolts 79 or other suitable fastening means passes through the respective holes in the supporting portion 59 and the insert 71 to hold the insert in a fixed position.

The pressing portion 69 extends lengthwise across the entire width of the abrasive belt 31 and coversthe entire width of the surface to be ground. The pressing portion 69 can be mounted substantially perpendicular to the direction of movement of the belt to grind very narrow work surfaces or be mounted obliquely to grind wider work surfaces.

The conveyor 33 is conveniently provided with a fence 81 which maintains the position of the work 35 on theconveyor belt 41. The abrasive belt 31 acts to drive the work into the fence 81. In some instances, where irregularly shaped workpieces are being finished, it may be necessary to provide bridging between the workpiece and the fence to maintain the proper position of the workpiece during grinding.

In operation, the grinding head is adjusted to the proper height above the conveyor belt 41 so as to achieve the removal of the proper amount of stock from the workpiece. The platen 57 is mounted so that the insert 71 extends across the belt and covers the entire width of the surface to be ground. workpieces are seamst ess r. strata. tits. as: $.22: into the abrasive belt 31 they are subjected to the grinding action. A nozzle can be employed to direct a stream of coolant between the abrasive belt and the workpiece to lubricate and cool the contacting surfaces.

A preferred embodiment of this invention having been described and. illustrated, it is to be realized that modifications thereof may be made without departing from the broad spirit and scope of this invention as described in the appended claims.

What is claimed is:

l. A grinding machine comprising a grinding head, a plurality of rolls mounted for rotation on said grinding head, an abrasive belt carried by said rolls and having an active run, a platen, means having a work conveying surface for feeding work into said abrasive belt and under said platen in a direction normal to the movement of said belt, means for rigidly mounting said platen above the active run of said abrasive belt, said platen comprising a supporting member and a single narrow pressing member rigidly mounted to said supporting member, said pressing member being of uniform width and having a bottom surface in a plane substantially parallel to the work conveying surface, said pressing member being adapted to be tensioned against said abrasive belt and extending obliquely across the width thereof.

2. A grinding machine according to claim 6 wherein said pressing means comprises a hard wear resistant material.

3. A grinding machine according to claim 2 wherein said pressing portion comprises an insert strip.

4. A grinding machine according to claim 3 wherein said pressing portion is less than about 1 inch in width.

5. A grinding machine according to claim 4 including a backing plate for securing said supporting member to said grinding head, said backing plate being adjustably attached to said support member.

Claims

1. A grinding machine comprising a grinding head, a plurality of rolls mounted for rotation on said grinding head, an abrasive belt carried by said rolls and having an active run, a platen, means having a work conveying surface for feeding work into said abrasive belt and under said platen in a direction normal to the movement of said belt, means for rigidly mounting said platen above the active run of said abrasive belt, said platen comprising a supporting member and a single narrow pressing member rigidly mounted to said supporting member, said pressing member being of uniform width and having a bottom surface in a plane substantially parallel to the work conveying surface, said pressing member being adapted to be tensioned against said abrasive belt and extending obliquely across the width thereof.