# US 12,004,793 B2 · Bi-Spring surgical hammer impact tools > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,004,793 B2 - Document ID: US12004793B2 - Status: Granted - Kind: B2 - Application number: 17/678,807 - Filed: 2022-02-23 - Published: 2022-09-01 - Granted: 2024-06-11 - Earliest claimed: 2021-02-26 - Assignees: Zimmer, Inc. - Applicants: Zimmer, Inc. - Inventors: David Levy - Web page: https://patentgrep.com/patent/US12004793B2 ## CPC - A61B 17/92: Impactors or extractors, e.g. for removing intramedullary devices {(insertion or extraction of artificial joints A61F2/4603)} - A61B 17/1624: {Drive mechanisms therefor} - A61B 17/1626: {Control means; Display units} - A61B 17/1628: {Motors; Power supplies} - A61B 17/1659: {Surgical rasps, files, planes, or scrapers} - A61B 17/1668: {for the upper femur (A61B17/164 takes precedence)} - A61B 17/921: {for intramedullary devices} - A61B 2017/0042: {with special provisions for gripping} - A61B 2017/00734: {battery operated} - A61B 2017/925: {a spring} - A61B 2017/928: {a spring} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract Disclosed herein are bi-spring surgical hammer impact tools and methods of use thereof. The bi-spring surgical hammer impact tools can include an elongated drive rod disposed in the housing and including an impact flange in a mid-region thereof. A tool implement can be mounted to a first end of the elongated drive rod. An impact shuttle can be mounted on the elongated drive rod and can include first and second impact surfaces opposing opposite faces of the impact flange. A plurality of annular teeth can be defined by an exterior surface of the impact shuttle. First and second springs can be disposed against opposite ends of the impact shuttle. A partial tooth pinion attached to a drive shaft and movable for engagement with the plurality of annular teeth of the impact shuttle can be included. ## Claims ### Claim 1 A bi-spring surgical impact tool comprising: a housing; an elongated drive rod disposed in the housing and including an impact flange in a mid-region thereof; a tool implement mounted to a first end of the elongated drive rod; an impact shuttle mounted on the elongated drive rod and including first and second impact surfaces opposing opposite faces of the impact flange and including a plurality of annular teeth on an exterior surface; a first spring disposed against a first end of the impact shuttle; a second spring disposed against a second end of the impact shuttle; a motor having a drive shaft; and a partial tooth pinion attached to the drive shaft and movable for engagement with the plurality of annular teeth of the impact shuttle. ### Claim 2 (depends on 1) The bi-spring surgical impact tool of claim 1, wherein the housing includes a handle and further comprising a battery pack mountable to the handle. ### Claim 3 (depends on 1) The bi-spring surgical impact tool of claim 1, wherein the drive rod is supported by a rear end cap and a forward end cap of the housing. ### Claim 4 (depends on 1) The bi-spring surgical impact tool of claim 1, wherein the impact shuttle is supported on the elongated drive rod by a forward bearing and a rearward bearing. ### Claim 5 (depends on 1) The bi-spring surgical impact tool of claim 1, wherein the first spring and the second spring are formed integrally with the impact shuttle. ### Claim 6 (depends on 1) The bi-spring surgical impact tool of claim 1, wherein a rear end of the elongated drive rod includes a stop collar at a rear end thereof. ### Claim 7 (depends on 1) The bi-spring surgical impact tool of claim 1, further comprising a motor block supporting a pair of bearings that support the drive shaft of the motor and defining an opening for receiving the elongated drive rod and the impact shuttle therein. ### Claim 8 (depends on 1) The bi-spring surgical impact tool of claim 1, further comprising a force control mechanism for adjusting a force level of the bi-spring surgical impact tool by selectively limiting an amount of travel of the elongated drive rod within the housing. ### Claim 9 (depends on 8) The bi-spring surgical impact tool of claim 8, wherein the force control mechanism includes a shaft helix member fixed to a rear end of the elongated drive rod and including a first helix surface that engages a corresponding second helix surface adjustably disposed within a rotary member. ### Claim 10 (depends on 9) The bi-spring surgical impact tool of claim 9, wherein the rotary member includes a plurality of detents, the force control mechanism including a yoke supporting a ball member in engagement with the plurality of detents in order to secure the rotary member in a plurality of positions. ### Claim 11 (depends on 10) The bi-spring surgical impact tool of claim 10, wherein a radius of each detent of the plurality of detents is larger than a radius of the first and second helix surfaces. ### Claim 12 (depends on 10) The bi-spring surgical impact tool of claim 10, wherein a radius of each detent of the plurality of detents is approximately twice a radius of an average helix radius. ### Claim 13 (depends on 9) The bi-spring surgical impact tool of claim 9, wherein the shaft helix member includes a pair of first helix surfaces and the rotary member includes a pair of second helix surfaces that engage the pair of first helix surfaces. ### Claim 14 A bi-spring surgical impact tool comprising: a housing; an elongated drive rod disposed in the housing and including an impact flange in a mid-region thereof; a tool implement mounted to a first end of the elongated drive rod; an impact shuttle mounted on the elongated drive rod and including first and second impact surfaces opposing opposite faces of the impact flange and including a plurality of gear teeth; a first spring disposed against a first end of the impact shuttle; a second spring disposed against a second end of the impact shuttle; a motor including a drive shaft; a pinion attached to the drive shaft and movable for engagement with the plurality of gear teeth of the impact shuttle; and a force control mechanism for adjusting a force level of the bi-spring surgical impact tool by selectively limiting an amount of travel of the elongated drive rod within the housing. ### Claim 15 (depends on 14) The bi-spring surgical impact tool of claim 14, wherein the drive rod is supported by a rear end cap and a forward end cap of the housing. ### Claim 16 (depends on 14) The bi-spring surgical impact tool of claim 14, wherein the impact shuttle is supported on the elongated drive rod by a forward bearing and a rearward bearing. ### Claim 17 (depends on 14) The bi-spring surgical impact tool of claim 14, wherein the first spring and the second spring are formed integrally with the impact shuttle. ### Claim 18 (depends on 14) The bi-spring surgical impact tool of claim 14, wherein a rear end of the elongated drive rod includes a stop collar at a rear end thereof. ### Claim 19 (depends on 14) The bi-spring surgical impact tool of claim 14, further comprising a motor block supporting a pair of bearings that support the drive shaft of the motor and including an opening for receiving the elongated drive rod and the impact shuttle therein. ### Claim 20 (depends on 14) The bi-spring surgical impact tool of claim 14, wherein the force control mechanism includes a shaft helix member fixed to a rear end of the drive rod and including a first helix surface that engages a corresponding second helix surface adjustably disposed within a rotary member.