US Patent 11685032 Rotary impact tool having bit holding device

A rotary impact tool includes a housing, an electric motor supported in the housing, and a drive assembly. The drive assembly includes an anvil having a longitudinal bore for selectively receiving a tool bit, and a plurality of radial slots extending from the longitudinal bore through the anvil. The rotary impact tool further includes a bit holding device including a plurality of ball detents received in the respective radial slots, and a collar slidably disposed on the anvil having an interior surface for maintaining a portion of the ball detents within the longitudinal bore, and collar spring for biasing the collar rearward to a first collar position. The bit holding device further includes a helical detent spring surrounding the anvil having a continuous helical structure with a plurality of protrusions extending into the radial slots, the protrusions are for biasing the ball detents toward an open end of the bore.