# US 12,759,121 B2 · Torque wrench profiled cam lock lever > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,759,121 B2 - Document ID: US12759121B2 - Status: Granted - Kind: B2 - Application number: 17/990,389 - Filed: 2022-11-18 - Published: 2024-05-23 - Granted: 2026-10-13 - Earliest claimed: 2022-11-18 - Assignees: Snap-on Incorporated - Applicants: Snap-on Incorporated - Inventors: Joshua Helstrom; Jeffrey D. Bergh; Hanna Feyissa; Patrick L. Mancini - Web page: https://patentgrep.com/patent/US12759121B2 ## CPC - B25B 23/1427: {by mechanical means} - B25G 1/105: {for screwdrivers, wrenches or spanners (B25G1/102, B25G1/125 take precedence)} - B25B: TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING, OR HOLDING - B25G: HANDLES FOR HAND IMPLEMENTS (attaching the blades or the like to handles of hand tools for soil working A01B1/22; handles of hand implements for harvesting A01D1/14; handles integral with brushware A46B) ## Abstract A torque wrench with a profiled cam lock lever that is movable between locked and unlocked positions over an adjustment knob of the tool. The lock lever includes an off-center pivot pin and a decreasing radius on a cam profile of the lock lever (rounded corner that contacts a housing of the tool when the lock lever is moved between the locked and unlocked positions). The off-center pivot pin increases an amount of force applied to the adjustment knob when the lock lever is in the locked position to minimize and/or prevent unintentional movement of the adjustment knob. The cam profile reduces an amount of force or effort needed to operate the lock lever and decreases rapid release of the lock lever as over center action is reached. ## Claims ### Claim 1 A torque wrench, comprising: a head portion adapted to engage a fastener; a handle portion coupled to the head portion and including an exterior surface with an aperture; an adjustment knob having a shaft extending into the handle portion, wherein the adjustment knob is adapted to be operated by a user to set a torque setting of the torque wrench; a lock lever selectively movable between locked and unlocked positions and including a bottom surface that is substantially flat and a rounded corner extending from the bottom surface and that forms a cam profile that is adapted to contact and cam against the exterior surface when the lock lever is moved between the locked and unlocked positions, wherein the cam profile includes a first radiused portion with a first radius proximal to the bottom surface and adapted to be disposed proximal to the exterior surface when the lock lever is disposed in the locked position, and a second radiused portion with a second radius greater than the first radius and adapted to be disposed proximal to the exterior surface when the lock lever is disposed in the unlocked position; a pivot pin coupled to the lock lever and disposed off-center with respect to the cam profile; and a bias member having first and second ends, wherein the first end is disposed in the handle portion and engages the shaft, and the second end extends through the aperture and engages the pivot pin, wherein when the lock lever is in the locked position, the lock lever at least partially covers a portion of the adjustment knob, the second end is disposed a first distance away from the exterior surface, and causes the bias member to have a potential energy and apply a first bias force to the shaft to cause the adjustment knob to be retained in position by frictional engagement with the exterior surface. ### Claim 2 (depends on 1) The torque wrench of claim 1, wherein the first radius is about 0.08 inches to about 0.18 inches. ### Claim 3 (depends on 2) The torque wrench of claim 2, wherein the first radius is about 0.1 inches to about 0.12 inches. ### Claim 4 (depends on 1) The torque wrench of claim 1, wherein the first distance is about 0.2 inches to about 0.35 inches. ### Claim 5 (depends on 4) The torque wrench of claim 4, wherein the first distance is about 0.273 inches. ### Claim 6 (depends on 1) The torque wrench of claim 1, wherein when the lock lever is in the locked position, the pivot pin causes a second bias force to be exerted on the second end. ### Claim 7 (depends on 6) The torque wrench of claim 6, wherein the second bias force is about 92 lbs. ### Claim 8 (depends on 7) The torque wrench of claim 7, wherein the potential energy is about 12.6 lb-in. ### Claim 9 A lock lever for a torque wrench, wherein the lock lever is selectively movable between a locked position that restricts movement of an adjustment knob and an unlocked position that allows movement of the adjustment knob, the lock lever comprising: a bottom surface that is substantially flat and a rounded corner extending from the bottom surface and that forms a cam profile that is adapted to contact and cam against a housing portion of the torque wrench when the lock lever is moved between the locked and unlocked positions, wherein the cam profile includes a first radiused portion with a first radius proximal to the bottom surface and adapted to be disposed proximal to the housing portion when the lock lever is disposed in the locked position, and a second radiused portion with a second radius greater than the first radius and adapted to be disposed proximal to the housing portion when the lock lever is disposed in the unlocked position; and a pivot pin that is off-center with respect to the cam profile. ### Claim 10 (depends on 9) The lock lever of claim 9, wherein a center of the pivot pin is disposed a first distance of about 0.17 inches to about 0.23 inches from a bottom surface of the lock lever. ### Claim 11 (depends on 10) The lock lever of claim 10, wherein the first distance is about 0.21 inches. ### Claim 12 (depends on 9) The lock lever of claim 9, wherein the first radius is about 0.08 inches to about 0.18 inches. ### Claim 13 (depends on 9) The lock lever of claim 9, wherein the second radius is about 0.15 inches to about 0.2 inches. ### Claim 14 (depends on 1) The torque wrench of claim 1, wherein the first radiused portion is adapted to contact and cam against the exterior surface when the lock lever is angularly disposed about 40 degrees from the locked position. ### Claim 15 (depends on 9) The lock lever of claim 9, wherein the first radiused portion is adapted to contact and cam against the housing portion when the lock lever is angularly disposed about 40 degrees from the locked position. ### Claim 16 A lock lever for a tool, wherein the lock lever is selectively movable between locked and unlocked positions, the lock lever comprising: a bottom surface that is substantially flat and a rounded corn er extending from the bottom surface and that forms a cam profile having a decreasing radiused portion adapted to contact and cam against a housing portion of the tool when the lock lever is moved between the locked and unlocked positions, wherein the decreasing radiused portion includes a first radiused portion with a first radius proximal to the bottom surface and that is adapted to be disposed proximal to an exterior of the tool when the lock lever is disposed in the locked position, and a second radiused portion with a second radius greater than the first radius and that is adapted to be disposed proximal to the exterior of the tool when the lock lever is disposed in the unlocked position. ### Claim 17 (depends on 16) The lock lever of claim 16, wherein the first radius is about 0.08 inches to about 0.18 inches. ### Claim 18 (depends on 17) The lock lever of claim 17, wherein the first radius is about 0.1 inches to about 0.12 inches. ### Claim 19 (depends on 16) The lock lever of claim 16, wherein the second radius is about 0.15 inches to about 0.2 inches. ### Claim 20 (depends on 19) The lock lever of claim 19, wherein the second radius is about 0.18 inches.