# US 10,369,640 B2 · Miter saw including a chain drive

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- Number: US 10,369,640 B2
- Document ID: US10369640B2
- Status: Granted
- Kind: B2
- Application number: 15/101,948
- Filed: 2014-12-08
- Published: 2016-10-20
- Granted: 2019-08-06
- Earliest claimed: 2013-12-11
- Assignees: Robert Bosch Tool Corporation; Robert Bosch GmbH
- Applicants: Robert Bosch GmbH
- Inventors: Plamen V. Marinov
- Web page: https://patentgrep.com/patent/US10369640B2

## CPC

- B23D 47/12: of drives for circular saw blades
- B23D 45/044: {the saw blade being adjustable according to angle of cut (B23D45/025 takes precedence)}
- B23D 45/046: {the pivoted lever being mounted on a carriage}
- B23D 45/048: {the saw blade being adjustable according to angle of cut}
- 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)

## Abstract

A powered saw including a saw blade configured to cut a workpiece and driven by a drive train having a narrow profile. The powered saw includes a miter saw having a chain drive disposed in a housing having a narrow profile. The powered saw includes a blade support assembly configured to reduce or eliminate interference between a workpiece and the powered saw. The miter saw enables a user to make right angle cuts, left angle cuts, and zero cuts of tall and atypically sized workpieces.

## Claims

### Claim 1

A power tool comprising:
a workpiece support structure having a workpiece support surface for supporting a workpiece thereon;
a motor supported by said workpiece support structure;
a cutting element configured to perform a cut in a workpiece, said cutting element having a drive input for driving the cutting element to perform the cut, said drive input configured to rotate about a first axis of rotation;
a drive assembly coupling said motor to said cutting element, including;
a first drive train extending from said motor to an offset position that is offset from said drive input; and
a second drive train comprising:
a second driving sprocket connected to said first drive train at the offset position in such a way that the first drive train drives the second driving sprocket about a second axis of rotation;
a second driven sprocket fixedly coupled to said drive input and configured such that rotation of said second driving sprocket rotates said drive input; and
a second chain engaging said second driving sprocket and said second driven sprocket and configured such that rotation of said second driving pulley or sprocket rotates said second driven sprocket, wherein said first and second drive trains are arranged such that a line connecting said second axis of rotation to said first axis of rotation is perpendicular to said first axis of rotation and arranged in a plane that is perpendicular to said workpiece support surface,
wherein said cutting element defines a cutting plane, and said drive assembly is arranged entirely on a first side of said cutting plane,
wherein said cutting plane intersects said motor such that a first portion of said motor is arranged on the first side of the cutting plane, and a second portion of said motor is arranged on a second side of the cutting plane, said first portion having a first length measured parallel to the first axis of rotation and said second portion having a second length measured parallel to the first axis of rotation, and the second length is greater than the first lengthy,
wherein said drive assembly further comprises a drive housing that defines a first end side of the drive assembly, the drive assembly having a second opposite end side, said first and second drive trains being entirely positioned between said first and second end sides,
wherein a distance between said first and second end sides measured along a direction parallel to said workpiece support surface and parallel to said first axis of rotation is less than one-third of an overall length of said motor measured along said direction, and
wherein said second drive train includes a tensioning mechanism engaging said second chain between said second driving sprocket and said second driven sprocket, said tensioning mechanism comprises:
a tensioning sprocket engaging said second chain and an adjuster configured to position the tensioning sprocket closer to or further away from said second chain so as to adjust a tension of said second chain.

### Claim 2 (depends on 1)

The power tool according to claim 1, wherein said first drive train includes:
a first driving pulley or sprocket coupled to an output of said motor;
a first driven pulley or sprocket at said offset position and connected to said second driving sprocket; and
a first belt or chain engaged between said first driving pulley or sprocket and said first driven pulley or sprocket, said line connecting a second axis of rotation of said first driven pulley or sprocket to said first axis of rotation.

### Claim 3 (depends on 2)

The power tool according to claim 2, wherein said second driving sprocket is coupled for rotation with said first driven pulley or sprocket about said second axis of rotation.

### Claim 4 (depends on 2)

The power tool according to claim 2, wherein a third axis of rotation about which said first driving pulley or sprocket is configured to rotate is vertically above said second axis of rotation relative to said workpiece support surface.

### Claim 5 (depends on 2)

The power tool according to claim 2, wherein:
said first driving pulley or sprocket has a first diameter; and
said first driven pulley or sprocket has a second diameter that is greater than the first diameter such that said first driven pulley or sprocket rotates at a slower rotational speed than said first driving pulley or sprocket.

### Claim 6 (depends on 1)

The power tool according to claim 1, wherein said offset position is vertically above said drive input of said cutting element relative to said workpiece support surface.

### Claim 7 (depends on 6)

The power tool according to claim 6, wherein said first and second drive trains define a clearance space between said drive assembly and said workpiece support surface that extends vertically above said drive input of said cutting element to provide clearance for a workpiece.

### Claim 8 (depends on 1)

The power tool according to claim 1, further comprising a bevel arm apparatus supporting said motor, cutting element and drive assembly on said workpiece support structure and configured to pivot said motor, cutting element and drive assembly to a bevel angle relative to said workpiece support surface.

### Claim 9 (depends on 8)

The power tool according to claim 8, wherein said drive assembly is configured to define a clearance space between said drive assembly and said workpiece support surface sufficient to permit pivoting by said bevel arm apparatus and said cutting element to a bevel angle of 45 degrees with respect to said workpiece support surface.

### Claim 10

A power tool comprising:
a workpiece support structure having a workpiece support surface for supporting a workpiece thereon;
a motor supported by said workpiece support structure;
a cutting element configured to perform a cut in a workpiece, said cutting element having a drive input for driving the cutting element to perform the cut and being configured to rotate about a first axis of rotation;
a drive assembly coupling said motor to said cutting element, including;
a first drive train comprising:
a first driving pulley coupled to an output of said motor and configured to rotate about a third axis of rotation;
a first driven pulley configured to rotate about a second axis of rotation at an offset position that is offset from said third axis of rotation; and
a first belt engaged between said first driving pulley or sprocket and said first driven pulley or sprocket, said first axis of rotation being vertically above said second axis of rotation relative to said workpiece support surface; and
a second drive train comprising:
a second driving sprocket fixedly connected to said driven pulley at the offset position in such a way that the first drive train drives the second driving sprocket;
a second driven sprocket fixedly coupled to said drive input and configured such that rotation of said second driving sprocket rotates said drive input; and
a second chain engaging said second driving sprocket and said second driven sprocket and configured such that rotation of said second driving sprocket rotates said second driven sprocket,
wherein said cutting element defines a cutting plane, and said drive assembly is arranged entirely on a first side of said cutting plane,
wherein said cutting plane intersects said motor such that a first portion of said motor is arranged on the first side of the cutting plane, and a second portion of said motor is arranged on a second side of the cutting plane, said first portion having a first length measured parallel to the first axis of rotation and said second portion having a second length measured parallel to the first axis of rotation, and the second length is greater than the first length,
wherein said drive assembly further comprises a drive housing that defines a first end side of the drive assembly, the drive assembly having a second opposite end side, said first and second drive trains being entirely positioned between said first and second end sides; and
wherein a distance between said first and second end sides measured along a direction parallel to said workpiece support surface and parallel to said first axis of rotation is less than a third of an overall length of said motor measured along said direction, wherein said second drive train includes a tensioning mechanism engaging said second chain between said second driving sprocket and said second driven sprocket.

### Claim 11 (depends on 10)

The power tool according to claim 10, wherein said second drive train is arranged such that a line connecting said first axis of rotation to said second axis of rotation is perpendicular to said first axis of rotation and arranged in a plane that is perpendicular to said workpiece support surface.

### Claim 12 (depends on 10)

The power tool according to claim 10,
wherein:
said first driving pulley has a first diameter; and
said first driven pulley has a second diameter that is greater than the first diameter such that said first driven pulley rotates at a slower rotational speed than said first driving pulley.

### Claim 13 (depends on 10)

The power tool according to claim 10, further comprising a tensioning mechanism that comprises:
a tensioning sprocket engaging said second chain; and
an adjuster configured to position the tensioning sprocket closer to or further away from said second chain so as to adjust a tension of said second chain.