# US 11,298,764 B2 · Circular saw that uses a prism to reflect the cut images

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- Number: US 11,298,764 B2
- Document ID: US11298764B2
- Status: Granted
- Kind: B2
- Application number: 16/915,222
- Filed: 2020-06-29
- Published: 2021-12-09
- Granted: 2022-04-12
- Earliest claimed: 2020-06-05
- Assignees: Durq Machinery Corp.
- Applicants: Durq Machinery Corp.
- Inventors: Chia-Sheng Liu; Yi-Li Cheng; Wen-Hung Lo
- Web page: https://patentgrep.com/patent/US11298764B2

## CPC

- B23D 59/003: {Indicating the cutting plane on the workpiece, e.g. by projecting a laser beam}
- B23D 45/16: Hand-held sawing devices with circular saw blades
- B27B 9/00: Portable power-driven circular saws for manual operation (details or components, e.g. handles, casings, of portable power-driven tools not particularly related to the operation performed B25F5/00)
- B27G 19/04: for manually-operated power-driven circular saws
- G02B 17/04: using prisms only
- B23D: PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR (making toothed gears or the like B23F; cutting metal by applying heat locally B23K; arrangements for copying or controlling B23Q)
- B27B: SAWS FOR WOOD OR SIMILAR MATERIAL; COMPONENTS OR ACCESSORIES THEREFOR (saws specially adapted for pruning or debranching A01G3/08; sawing apparatus specially adapted for felling trees A01G23/091; features not restricted to a particular type of wood saw B23D, e.g. attaching saw blades B23D51/00; machine tool frames, beds, pillars or like members, in general B23Q1/01)
- B27G: ACCESSORY MACHINES OR APPARATUS FOR WORKING WOOD OR SIMILAR MATERIALS; TOOLS FOR WORKING WOOD OR SIMILAR MATERIALS (tools for grinding B24D; sawing tools B27B33/00; tools for slotting or mortising machines B27F5/02; tools for the manufacture of wood shavings, chips, powder or the like B27L11/00); SAFETY DEVICES FOR WOOD WORKING MACHINES OR TOOLS
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A circular saw includes a housing, a sawing assembly including a motor and a saw blade located at two opposite sides of the housing and connected together so that the saw blasé can be driven by the motor to saw the workpiece and a saw blade shield secured to the housing and covering a part of the saw blade to prevent the saw blade from cutting the surrounding people, and a prism assembly including a protective cover affixed to the front end of the saw blade shield and a prism located in the protective cover to reflect the image of the saw blade sawing the workpiece through a window of the protective cover to the line of sight of the operator. In this way, the operator can clearly confirm whether the sawing path is skewed with the normal operating posture to improve the efficiency.

## Claims

### Claim 1

A circular saw for sawing a workpiece, said circular saw comprising:
a housing;
a sawing assembly comprising a motor, a saw blade and a saw blade shield, said motor being located on one side of said housing, said saw blade being located on an opposite side of said housing and connected to said motor so that said saw blade is drivable by said motor to saw said workpiece, said saw blade shield being secured to said housing and covering a part of said saw blade; and
a prism assembly located in front of said saw blade, said prism assembly comprising a protective cover, a transparent protective plate, a scraper for scraping off impurities attach to a surface of the transparent protective plate, and at least one prism, said protective cover being affixed to a front end of said saw blade shield, said protective cover comprising a window located on a top surface thereof and an opening located on a bottom surface thereof, said at least one prism being located in said protective cover, each said prism comprising an incident surface, a reflective surface located in front of said incident surface, and an exit surface located above said reflective surface, said incident surface receiving an image of said saw blade sawing said workpiece through said opening of said protective cover, said reflective surface reflecting the image received by said incident surface to said exit surface, said exit surface emitting the image reflected from said reflective surface through said window of said protective cover;
wherein the image shows a point at which the said saw blade cuts a workpiece, and said reflective surface of said prism is located in front of said point.

### Claim 2 (depends on 1)

The circular saw as claimed in claim 1, wherein said protective cover has a top thereof provided with an infrared generator in front of said window, said infrared generator being adapted to emit an infrared beam to a surface of said workpiece.

### Claim 3 (depends on 1)

The circular saw as claimed in claim 1, wherein the transparent protective plate is provided at said opening of said protective cover to face said incident surface of the at least one prism.

### Claim 4 (depends on 3)

The circular saw as claimed in claim 3, wherein said protective cover comprises a long slot; said prism assembly further comprises a mobile plate, said mobile plate being movably mounted in said long slot and comprising a hollow groove for allowing said transparent protective plate to expose to outside, said mobile plate having one end thereof protruding out of said protective cover and forming an operating portion, said scraper being affixed to an opposite end of said mobile plate and abutted at said transparent protective plate.

### Claim 5 (depends on 1)

The circular saw as claimed in claim 1, wherein said housing has one side thereof provided with a light source, said light source being used to emit light at a contact position of said saw blade and said workpiece.

### Claim 6 (depends on 1)

The circular saw as claimed in claim 1, wherein the at least one prism of said prism assembly comprises two prisms, which are a lower prism and an upper prism located above said lower prism, the incident surface of said lower prism receiving the image of said saw blade sawing said workpiece through said opening of said protective cover, the reflective surface of said lower prism reflecting the image received by the incident surface of said lower prism to the exit surface of said lower prism, the exit surface of said lower prism emitting the image reflected by the reflective surface of said lower prism to the incident surface of said upper prism, the incident surface of said upper prism receiving the image from the exit surface of said lower prism, the reflective surface of said upper prism reflecting the image received by the incident surface of said upper prism to the exit surface of said upper prism, the exit surface of said upper prism emitting the image reflected from the reflective surface of said upper prism through said window of said protective cover.

### Claim 7 (depends on 1)

The circular saw as claimed in claim 1, wherein at least one of said incident surface, said reflective surface and said exit surface is flat.

### Claim 8 (depends on 7)

The circular saw as claimed in claim 7, wherein said incident surface, said reflective surface and said exit surface are all flat.