Orthopedic impactor
An orthopedic impactor may include a motor operable to generate first rotational motion and second rotational motion, a linear motion converter operatively coupled to the motor to convert the first rotational motion into first linear motion and the second rotational motion into second linear motion, an anvil including at least one impact surface, and a thrown mass having a first position located a distance from the at least one impact surface. The thrown mass may accelerate, responsive to the first linear motion and away from the first position, toward the anvil to impact the at least one impact surface with a first kinetic energy and impart a linear impact force on the anvil. The thrown mass may return, responsive to the second linear motion and toward the first position, with a second kinetic energy that is less than the first kinetic energy.
1 . An orthopedic impactor, comprising:
a motor operable to generate first rotational motion and second rotational motion, the first rotational motion and the second rotational motion being opposite in direction;
a linear motion converter operatively coupled to the motor to convert the first rotational motion into first linear motion and the second rotational motion into second linear motion, the first linear motion and the second linear motion being opposite in direction;
an anvil including at least one impact surface; and
a thrown mass operatively coupled to the linear motion converter having a first position located a distance from the at least one impact surface,
wherein, during an operational cycle of the orthopedic impactor:
the thrown mass accelerates, responsive to the first linear motion and away from the first position, toward the anvil to impact the at least one impact surface with a first kinetic energy and impart a linear impact force on the anvil, and
the thrown mass returns, responsive to the second linear motion and toward the first position, with a second kinetic energy that is less than the first kinetic energy.
2 . The orthopedic impactor of claim 1 , wherein the second kinetic energy is at least 50% less than the first kinetic energy when the thrown mass is within 15 millimeters of the first position.
3 . The orthopedic impactor of claim 1 , wherein the first kinetic energy corresponds to a kinetic energy of the thrown mass when the thrown mass is 25 millimeters or less away from the at least one impact surface and the second kinetic energy is at least 40% less than the first kinetic energy.
4 . The orthopedic impactor of claim 1 , wherein a motor output power is reduced to provide the second rotational motion during movement of the thrown mass toward the first position.
5 . The orthopedic impactor of claim 1 , wherein an anvil stroke is 18 millimeters or less responsive to the first kinetic energy.
6 . The orthopedic impactor of claim 1 , wherein the linear motion converter includes a lead screw and lead nut assembly.
7 . The orthopedic impactor of claim 1 , wherein the linear motion converter includes a belt and pulley assembly.
8 . The orthopedic impactor of claim 1 , wherein the linear motion converter includes a chain and sprocket assembly.
9 . The orthopedic impactor of claim 1 , wherein the linear motion converter includes a rack and pinion assembly.
10 . The orthopedic impactor of claim 1 , wherein the linear motion converter includes a ball screw and ball nut assembly.
11 . The orthopedic impactor of claim 1 , wherein the motor and the linear motion converter operate along distinct parallel axes.
12 . An orthopedic impactor, comprising:
a motor operable to generate rotational motion;
a means for converting the rotational motion to linear motion;
an anvil including at least one impact surface; and
a thrown mass having a first position located a distance from the at least one impact surface,
wherein, during an operational cycle of the orthopedic impactor:
the thrown mass accelerates, responsive to the linear motion and away from the first position, toward the anvil to impact the at least one impact surface with a first kinetic energy and impart a linear impact force on the anvil, and
the thrown mass returns, responsive to the linear motion and toward the first position, with a second kinetic energy that is less than the first kinetic energy.
13 . The orthopedic impactor of claim 12 , wherein the second kinetic energy is at least 50% less than the first kinetic energy.
14 . The orthopedic impactor of claim 12 , wherein the first kinetic energy corresponds to a kinetic energy of the thrown mass when the thrown mass is 25 millimeters or less away from the at least one impact surface and the second kinetic energy is at least 40% less than the first kinetic energy.
15 . The orthopedic impactor of claim 12 , wherein a motor output power is reduced to provide the second rotational motion during movement of the thrown mass toward the first position.
16 . The orthopedic impactor of claim 12 , wherein an anvil stroke is 18 millimeters or less responsive to the first kinetic energy.
17 . The orthopedic impactor of claim 12 , wherein the motor and the linear motion converter operate along distinct parallel axes.
18 . An orthopedic impactor, comprising:
a motor configured to generate rotational motion;
a linear motion converter operatively coupled to the motor and configured to convert the rotational motion into linear motion;
a thrown mass operatively coupled to the linear motion converter and movable between a ready position and an impact position;
an anvil including at least one impact surface positioned to receive impact from the thrown mass; and
a controller configured to:
control the motor to accelerate the thrown mass from the ready position toward the impact position with a first kinetic energy magnitude, and
control the motor to return the thrown mass from the impact position toward the ready position with a second kinetic energy magnitude that is reduced relative to the first kinetic energy magnitude.
19 . The orthopedic impactor of claim 18 , wherein the controller is further configured to modulate a motor output power during the return of the thrown mass such that the second kinetic energy magnitude is at least 50% less than the first kinetic energy magnitude.