Impact tools with speed controllers

摘要

Illustrative embodiments of impact tools with speed controllers and methods of controlling such impact tools are disclosed. In at least one illustrative embodiment, an impact tool may comprise a ball-and-cam impact mechanism including a hammer and an anvil. The hammer may be configured to rotate about a first axis and to translate along the first axis to impact the anvil to cause rotation of the anvil about the first axis. The impact tool may further comprise a motor and a speed controller. The motor may include a rotor configured to rotate when a flow of compressed fluid is supplied to the rotor to drive rotation of the hammer of the ball-and-cam impact mechanism. The speed controller may be coupled to the rotor and may be configured to throttle the flow of compressed fluid supplied to the rotor based on a rotational speed of the rotor.

主权项

1. An impact tool comprising:
a ball-and-cam impact mechanism comprising a hammer and an anvil, the hammer being configured to rotate about a first axis and to translate along the first axis to impact the anvil to cause rotation of the anvil about the first axis; a motor including a rotor configured to rotate when a flow of compressed fluid is supplied to the rotor to drive rotation of the hammer of the ball-and-cam impact mechanism; and a speed controller coupled to the rotor and configured to throttle the flow of compressed fluid supplied to the rotor based on a rotational speed of the rotor; and an orifice through which the flow of compressed fluid passes, wherein the speed controller is configured to throttle the flow of compressed fluid supplied to the rotor by regulating a size of the orifice; wherein the speed controller comprises:
a plunger movable to reduce the size of the orifice;a spring biasing the plunger away from the orifice; andone or more masses configured to exert a force on the plunger, in response to rotation of the rotor, to overcome the spring bias; wherein the size of the orifice is regulated by:
a reduced size of the orifice by a first amount in response to the rotational speed of the rotor being a first speed; anda second reduced size of the orifice by a second amount greater than the first amount in response to the rotational speed of the rotor being a second speed greater than the first speed;wherein if the rotational speed of the rotor exceeds a predefined threshold speed the size of the orifice regulates the rotational speed of the motor by changing between the reduced size and the second reduced size to maintain the predefined threshold speed; and wherein the predefined threshold speed is based on the group selected from at least one of characteristics of the spring and weight of the one or more masses.