# US 5,341,606 A · Device for cutting and grinding a doughnut shaped substrate and a method therefor

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- Number: US 5,341,606 A
- Document ID: US5341606A
- Status: Granted
- Kind: A
- Application number: 08/006,506
- Filed: 1993-01-19
- Granted: 1994-08-30
- Earliest claimed: 1992-01-29
- Assignees: Kyokuei Kenmakako Kabushiki Kaisha
- Inventors: Toshihiko Hirabayashi
- Web page: https://patentgrep.com/patent/US5341606A

## CPC

- B24B 9/10: of plate glass
- B24D 7/18: Wheels of special form
- B28D 1/041: {with cylinder saws, e.g. trepanning; saw cylinders, e.g. having their cutting rim equipped with abrasive particles}
- Y10T 408/03: Processes
- B24B: MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING (grinding of gear teeth B23F, of screw-threads B23G1/36; by electro-erosion B23H; abrasive or related blasting B24C; tools for grinding, buffing or sharpening B24D; polishing compositions C09G1/00; abrasives C09K3/14; electrolytic etching or polishing C25F3/00; grinding arrangements for use on assembled railway tracks E01B31/17); DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24D: TOOLS FOR GRINDING, BUFFING OR SHARPENING (abrading-bodies specially designed for tumbling apparatus, e.g. abrading-balls B24B31/14; honing tools B24B33/08; lapping tools B24B37/11)
- B28D: WORKING STONE OR STONE-LIKE MATERIALS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A device and method for cutting and grinding a hard but brittle material (such as glass plate, etc.) for producing a doughnut-shaped substrate are provided. The device of the present invention comprises a tubular core rod and shank extending therefrom and coaxial therewith. A plate is attached to the rod and shank and extends therefrom. A skirt is attached to the plate and surrounds the rod. Both the rod and skirt include at least one circumferential cavity. A core drill and a skirt drill are integral with the core rod and skirt, respectively. The cavities, skirt, and drills include diamond whetstone parts.

## Claims

### Claim 1

A method for cutting and grinding a hard but brittle material to produce a doughnut shaped substrate having an inner circumference and an outer periphery, and comprising the steps of:
a. associating a core drill with a skirt drill of a cutting and grinding device in contact with said material, each said drill having at least one circumferential cavity provided with diamond whetstone parts;
b. cutting out and grinding a doughnut shaped substrate from said material by rotating and advancing said cutting and grinding device in contact with said material while providing eccentric motion between the drill of said device and said material;
c. moving said doughnut shaped substrate with respect to said device so that said substrate becomes at least partially contained within said device;
d. contacting the inner circumference and the outer periphery of said substrate with the circumferential cavities of said core and skirt drills, respectively, and providing an eccentric movement between said device and said substrate;
wherein the drilling speed of said drills is reduced after initially penetrating into said material, and said drilling speed of said drills is adjusted so that said drills are advanced to a position of about 3/4 thickness of the whole thickness of the material in about one half of total drilling time, and thereafter the drilling speed of the drills is reduced so that the remaining thickness of 1/4 of the whole thickness of the material is drilled out in the other half of the total drilling time.

### Claim 2 (depends on 1)

A method according to claim 1, wherein said circumferential cavities have trapezoidal shapes.

### Claim 3 (depends on 1)

A method according to claim 1, wherein said whetstone parts of said core drill are on an outside portion thereof.

### Claim 4 (depends on 1)

A method according to claim 1, and further comprising the step of supplying a liquid to said material during cutting and grinding thereof for cooling said drills and for washing away particulate matter generated during said cutting and grinding.

### Claim 5 (depends on 4)

A method according to claim 4, wherein said liquid is supplied to said material from a plurality of liquid discharging outlets in said skirt.

### Claim 6 (depends on 1)

A method according to claim 1, wherein said core drill comprises two circumferential cavities.

### Claim 7 (depends on 1)

A method according to claim 1, wherein said skirt drill comprises two circumferential cavities.

### Claim 8 (depends on 1)

A method according to claim 1, wherein each said core rod and skirt comprise two circumferential cavities.