US Patent 10363650 Driving tool

In a rack and pinion mechanism 80, a driving-side pinion gear 83 and a driven-side pinion gear 86 are provided to be coaxially rotatable relative to each other within a predetermined angle range. Because of this construction, in a case where a time when a driver 3 reaches an advancing end position and contacts an advancing end damper 19 deviates from a time when a weight device 5 reaches a retracting end position and contacts a moving end damper 7, an excessive external force is not applied to engaging teeth 81a and 82a by relative rotation of the pinion gears 83 and 86. Thus, due to this construction, durability of the rack and pinion mechanism 80, where end impacts are absorbed through elastic deformation, is improved.