# US 2022/0032437 A1 · Impact mechanism with multi-material striker > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0032437 A1 - Document ID: US20220032437A1 - Status: Published application - Kind: A1 - Application number: 17/392,386 - Filed: 2021-08-03 - Published: 2022-02-03 - Earliest claimed: 2020-08-03 - Assignees: Milwaukee Electric Tool Corporation - Applicants: Milwaukee Electric Tool Corporation - Inventors: Will Didier; Tyler Young; Kevin A. McLachlan - Web page: https://patentgrep.com/patent/US20220032437A1 ## CPC - B25D 17/06: Hammer pistons; Anvils {; Guide-sleeves for pistons} - B25D 11/04: in which the tool bit or anvil is hit by an impulse member - B25D 2211/003: Crossed drill and motor spindles - B25D 2211/068: Crank-actuated impulse-driving mechanisms - B25D 2217/0015: Anvils - B25D 2217/0023: Pistons - B25D 2222/42: Steel - B25D 2222/51: Hard metals, e.g. tungsten carbide - B25D 2250/191: Ram catchers for stopping the ram when entering idling mode - B25D 2250/375: Fluid springs - B25D: PERCUSSIVE TOOLS {(percussive machines for forging B21J; hand-held drilling machines, in general B23B45/00, for wood B27C3/08; drilling machines, used for mining or quarrying, with reciprocating tool which is turned intermittently when out of contact with the working face E21B1/00)} ## Abstract An impact mechanism for use in a power tool having a motor and adapted to impart axial impacts to a tool bit. The impact mechanism includes a piston configured to reciprocate in response to receiving torque from the motor, a striker that is selectively reciprocable within the spindle in response to reciprocation of the piston, and an anvil that is impacted by the striker when the striker reciprocates towards the tool bit. The anvil imparts axial impacts to the tool bit. The striker includes a body portion formed of a first material and an insert portion within the body portion. The insert portion is formed of a second material that is more dense than the first material. ## Claims ### Claim 1 An impact mechanism for use in a power tool having a motor and adapted to impart axial impacts to a tool bit, the impact mechanism comprising: a piston configured to reciprocate in response to receiving torque from the motor; a striker that is selectively reciprocable within the spindle in response to reciprocation of the piston; and an anvil that is impacted by the striker when the striker reciprocates towards the tool bit, the anvil imparting axial impacts to the tool bit, wherein the striker includes a body portion formed of a first material and an insert portion within the body portion, the insert portion being formed of a second material that is more dense than the first material. ### Claim 2 (depends on 1) The impact mechanism of claim 1, wherein the insert portion is a cylindrical slug. ### Claim 3 (depends on 1) The impact mechanism of claim 1, wherein the body portion includes a cavity into which the insert portion is received. ### Claim 4 (depends on 3) The impact mechanism of claim 3, wherein the insert portion is a cylindrical slug, and wherein the cavity has a cylindrical shape to receive the cylindrical slug. ### Claim 5 (depends on 1) The impact mechanism of claim 1, wherein the first material is steel, and wherein the second material is tungsten carbide. ### Claim 6 (depends on 1) The impact mechanism of claim 1, wherein the striker includes a nose that impacts the anvil. ### Claim 7 (depends on 6) The impact mechanism of claim 6, wherein the insert portion is positioned within the body portion on a side of the striker that is opposite the nose. ### Claim 8 (depends on 1) The impact mechanism of claim 1, wherein the impact mechanism is disposed within a spindle of the power tool. ### Claim 9 (depends on 8) The impact mechanism of claim 8, wherein the piston is operable to create a variable pressure air spring within the spindle. ### Claim 10 (depends on 1) The impact mechanism of claim 1, wherein the insert portion is press fit into the body portion. ### Claim 11 A rotary hammer adapted to impart axial impacts to a tool bit, the rotary hammer comprising: a housing; a motor supported by the housing; a spindle coupled to the motor for receiving torque from the motor, causing the spindle to rotate; a reciprocation mechanism operable to create a variable pressure air spring within the spindle, the reciprocation mechanism including a piston configured to reciprocate within the spindle in response to receiving torque from the motor, a striker that is selectively reciprocable within the spindle in response to reciprocation of the piston, and an anvil that is impacted by the striker when the striker reciprocates towards the tool bit, the anvil imparting axial impacts to the tool bit; and a bit retention assembly for securing the tool bit to the spindle, wherein the striker includes a body portion formed of a first material and an insert portion within the body portion, the insert portion being formed of a second material that is more dense than the first material. ### Claim 12 (depends on 11) The rotary hammer of claim 11, wherein the insert portion is a cylindrical slug. ### Claim 13 (depends on 11) The rotary hammer of claim 11, wherein the body portion includes a cavity into which the insert portion is received. ### Claim 14 (depends on 13) The rotary hammer of claim 13, wherein the insert portion is a cylindrical slug, and wherein the cavity has a cylindrical shape to receive the cylindrical slug. ### Claim 15 (depends on 11) The rotary hammer of claim 11, wherein the first material is steel, and wherein the second material is tungsten carbide. ### Claim 16 (depends on 11) The rotary hammer of claim 11, wherein the striker includes a nose that impacts the anvil. ### Claim 17 (depends on 16) The rotary hammer of claim 16, wherein the insert portion is positioned within the body portion on a side of the striker that is opposite the nose. ### Claim 18 (depends on 11) The rotary hammer of claim 11, wherein the insert portion is press fit into the body portion. ### Claim 19 A rotary hammer adapted to impart axial impacts to a tool bit, the rotary hammer comprising: a housing; a motor supported by the housing; a spindle coupled to the motor for receiving torque from the motor, causing the spindle to rotate; a reciprocation mechanism operable to create a variable pressure air spring within the spindle, the reciprocation mechanism including a piston configured to reciprocate within the spindle in response to receiving torque from the motor, a striker that is selectively reciprocable within the spindle in response to reciprocation of the piston, the striker including a nose at one end thereof, and an anvil that is impacted by the nose of the striker when the striker reciprocates towards the tool bit, the anvil imparting axial impacts to the tool bit; and a bit retention assembly for securing the tool bit to the spindle, wherein the striker includes a body portion, which includes the nose, formed of a first material, and an insert portion within an end of the body portion opposite the nose, the insert portion being formed of a second material that is more dense than the first material. ### Claim 20 (depends on 19) The rotary hammer of claim 19, wherein the first material is steel, wherein the second material is tungsten carbide, wherein the insert portion is a cylindrical slug, and wherein the body portion includes a cylindrical cavity in which the cylindrical slug is received.