# US 2023/0265641 A1 · Microtrenching blades with replaceable cutters

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- Number: US 2023/0265641 A1
- Document ID: US20230265641A1
- Status: Published application
- Kind: A1
- Application number: 18/172,545
- Filed: 2023-02-22
- Published: 2023-08-24
- Earliest claimed: 2022-02-23
- Assignees: The Charles Machine Works, Inc.
- Applicants: The Charles Machine Works, Inc.
- Inventors: Michael C. Walgren
- Web page: https://patentgrep.com/patent/US20230265641A1

## CPC

- E02F 5/08: with digging wheels turning round an axis {(E02F5/109 takes precedence; with digging wheels per se E02F3/18)}
- E02F 9/2866: {for rotating digging elements (for milling machines B28D1/186; for mining machines E21C35/18)}
- E02F 5/101: {forming during digging, e.g. underground canalisations or conduits, by bending or twisting a strip of pliable material; by extrusion}
- E02F 9/2833: {Retaining means, e.g. pins}
- E02F 9/285: {characterised by the material used}
- E02F 9/2858: {characterised by shape}
- E02F: DREDGING; SOIL-SHIFTING (winning peat E21C49/00)

## Abstract

A replaceable tooth assembly. A number of tooth assemblies are provided round the periphery of a microtrenching blade. The assemblies include a cartridge, usually welded to the periphery of the microtrenching blade, and a tooth, which has a projection or flange shaped to fit within a cavity formed in the cartridge. The cartridge and projection each have a transverse hole formed in them, which, when aligned, form a continuous passage for placement of a removable pin which is used to join the cartridge to the tooth body. The cartridge may also have a more radially-aligned channel which intersects the cavity, which a rubber shim may be placed in. Such a shim reduces the relative vibration between the tooth and cartridge, improving life and reducing wear.

## Claims

### Claim 1

An apparatus, comprising:
a disc having a center and terminal periphery; and
a plurality of tooth assemblies, comprising:
a cartridge attached to the periphery of the disc, the cartridge having a cavity opening away from the center of the disc; and
a tooth configured for removable attachment to the cartridge.

### Claim 2 (depends on 1)

The apparatus of claim 1 wherein the cavity defines a profile, and:
the tooth comprises:
a body having a forward cutting face;
a projection extending from the body, wherein the projection has an external profile complementary to the profile of the cavity, and wherein the projection defines a cross-hole.

### Claim 3 (depends on 2)

The apparatus of claim 2 further comprising a pin configured for placement in the cross-hole.

### Claim 4 (depends on 2)

The apparatus of claim 2 wherein the cartridge comprises a channel, the channel having a first opening within the cavity and a second opening at a surface of the cartridge, wherein the channel is substantially radially oriented.

### Claim 5 (depends on 4)

The apparatus of claim 4 further comprising a shim, configured for placement within the channel.

### Claim 6 (depends on 5)

The apparatus of claim 5 in which the shim is made of a rubber material.

### Claim 7 (depends on 5)

The apparatus of claim 5 in which:
the projection is within the cavity;
the shim is within the channel; and
the shim contacts the projection at the first opening of the channel.

### Claim 8

A method of replacing a tooth in a microtrenching blade, wherein the tooth is located in one of a plurality of cartridges affixed to an outer periphery of the blade, the method comprising:
removing a cross-pin from a continuous passage formed by a transverse hole in the cartridge and an aligned transverse hole in a projection in the tooth; and
removing the projection from a cavity in the cartridge.

### Claim 9 (depends on 8)

The method of claim 8 further comprising:
choosing a replacement tooth;
placing a projection of the replacement tooth into the cavity of the cartridge;
placing a cross-pin into a continuous passage formed by the transverse hole in the cartridge and an aligned transverse hole in the projection of the replacement tooth.

### Claim 10 (depends on 8)

The method of claim 8 further comprising:
providing a rubber shim within a substantially radial channel, wherein the substantially radial channel intersects a cavity in the cartridge and wherein the shim is configured to contact the projection when within the channel.

### Claim 11 (depends on 8)

The method of claim 8 in which the substantially radial channel is open to the cavity of the cartridge along more than half of the length of the channel.

### Claim 12 (depends on 8)

The method of claim 8 in which the tooth comprises a forward face supporting at least two cutters.

### Claim 13

A tooth assembly configured for placement about the periphery of a microtrenching blade, the tooth assembly comprising:
a cartridge having an external surface and an internal cavity defining an internal profile;
wherein the internal cavity opens to the external surface of the cartridge at a first side; and
wherein the cavity is intersected by a transverse hole extending from a second side of the external surface to an opposed third side of the external surface; and
a tooth comprising:
a body; and
a projection extending from the body, wherein the projection defines an external profile complementary to the internal profile of the internal cavity of the cartridge, and wherein a transverse hole is formed in the projection;
wherein the transverse hole of the projection and the transverse hole of the cartridge form a continuous passage when the projection is situated within the internal cavity of the cartridge.

### Claim 14 (depends on 13)

The tooth assembly of claim 13 further comprising:
a cross-pin configured for placement within the continuous passage.

### Claim 15 (depends on 13)

The tooth assembly of claim 13 wherein:
the body extends from the projection to a terminal end, and comprises two cutters disposed at the terminal end on a forward face;
wherein a channel is defined on the body between the cutters and extends from the forward face to a rearward face.

### Claim 16 (depends on 15)

The tooth assembly of claim 15 in which the channel is u-shaped at the forward face and v-shaped at the rearward face.

### Claim 17 (depends on 15)

The tooth assembly of claim 15 in which the cutters are made of a harder material than the body.

### Claim 18 (depends on 13)

A blade comprising:
a disc; and
a plurality of the tooth assemblies of claim 13, each of the tooth assemblies being positioned at a periphery of the disc.

### Claim 19 (depends on 18)

The blade of claim 18 in which the plurality of tooth assemblies are welded to the periphery of the disc.

### Claim 20 (depends on 13)

The tooth assembly of claim 13, wherein:
the cartridge defines a substantially radial channel opening at a first end on the first side of the cartridge and intersecting the cavity, and further comprising:
a shim configured to compress against the projection of the tooth when the projection is within the internal cavity and the shim is within the substantially radial channel.