# US 4,398,375 A · High speed power sander and sanding pad therefor

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- Number: US 4,398,375 A
- Document ID: US4398375A
- Status: Granted
- Kind: A
- Application number: 06/334,155
- Filed: 1981-12-24
- Granted: 1983-08-16
- Earliest claimed: 1981-12-24
- Inventors: John Malyuk
- Web page: https://patentgrep.com/patent/US4398375A

## CPC

- A61H 7/005: {hand-held}
- A61H 23/0254: {with rotary motor}
- B24B 23/04: with oscillating grinding tools; Accessories therefor
- A61H 2201/018: By limiting the applied torque or force
- A61H: PHYSICAL THERAPY APPARATUS, e.g. DEVICES FOR LOCATING OR STIMULATING REFLEX POINTS IN THE BODY; ARTIFICIAL RESPIRATION; MASSAGE; BATHING DEVICES FOR SPECIAL THERAPEUTIC OR HYGIENIC PURPOSES OR SPECIFIC PARTS OF THE BODY (electrotherapy, magnetotherapy, radiation therapy or ultrasound therapy A61N)
- 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

## Abstract

A high speed reciprocating or orbiting power sander to the back-up plate of which a sanding pad of resiliently deformable elastomeric material is secured, the pad having numerous discrete laterally projecting fingers with coplanar rounded ends engaged with, but unsecured to, the uncoated side of the sandpaper. When the sander is in operation the rounded ends of the fingers have a back and forth or circular massaging action on the sandpaper to quickly achieve smooth finishes on the work being sanded, to prevent clogging of the sandpaper, and to greatly increase the life of the sandpaper.

## Claims

### Claim 1

A high speed power sander having an oscillating back-up plate to which one side of a sanding pad 30 to 40 Durometer hardness resiliently deformable elastomeric material is secured; said pad having on the other side numerous integral spaced apart discrete laterally projecting generally cylindrical fingers of height at least as great as the diameter thereof and terminating in coplanar rounded ends; and means on said plate for detachably securing thereto the ends of a strip of sandpaper with the uncoated side engaged with, but unsecured to, said rounded ends whereby said fingers constitute a resilient support for the sandpaper when pressed against work to be sanded and are flexed to cause the rounded ends thereof to exert a massaging action on the sandpaper to prevent clogging thereof by sanded material of the work and to form a smooth finish on the work.

### Claim 2 (depends on 1)

The sander of claim 1 wherein said fingers are of height not greater than about twice the diameter thereof.

### Claim 3 (depends on 1)

The sander of claim 1 wherein said fingers are spaced apart a center-to-center distance about twice the diameter thereof.

### Claim 4

A rectangular sanding pad for attachment to the oscillatable back-up plate of a high speed power sander comprising a sheet of 30 to 40 Durometer hardness rubber-like resiliently deformable material having numerous integral spaced apart discrete laterally projecting generally cylindrical fingers of height at least as great as the diameter thereof and terminating in coplanar rounded ends adapted to form a resilient support for sandpaper affixed to said plate; said fingers during oscillation being adapted to be flexed to cause the rounded ends to exert a massaging action on the sandpaper.

### Claim 5 (depends on 4)

The sanding pad of claim 4 wherein said fingers are of height not greater than about twice the diameter thereof.

### Claim 6 (depends on 4)

The sanding pad of claim 4 wherein said fingers are spaced apart a center-to-center distance about twice the diameter thereof.