Fastener Driving Tool

A fastener driving tool comprising:

• a housing having two housing halves which are matingly engaged with each other to define a housing space, a pivot axle which is disposed in said housing space, and a fastener striking opening at a bottom of a forward end of said housing;
• a striking member mounted in said housing for reciprocal movement in an up-and-down direction, said striking member having a lower striking end which faces said fastener striking opening, and an upper driven end which is formed with an engaged slot;
• an energy storing unit disposed in said housing space, and including an energy storing assembly which has at least one torsion spring that is twistable about a fixed axle disposed rearwardly of said pivot axle, said torsion spring having a short leg and a long leg which extend tangentially and forwardly, said long leg extending beyond said short leg to engage with said striking member, said energy storing unit further including a return spring which is disposed downwardly of said short leg to be compressed by said short leg to store a return energy;
• and
• a handle unit including a handle having a front pivot end which is pivotably mounted in said housing space and on said pivot axle, a rear effort end which is opposite to said front pivot end, and a forcing portion which is interposed between said front pivot end and said rear effort end and which is disposed to force said short leg to move downwardly when said rear effort end is turned about said pivot axle, said handle unit further including an anchoring member which is slidably mounted to said front pivot end of said handle and which has a forward anchoring portion that projects forwardly of said front pivot end to be engaged in said engaged slot of said striking member, and a biasing member which is disposed to bias said anchoring member forwardly such that said handle is pivotally movable relative to said pivot axle from a ready position, where said lower striking end of said striking member is in close proximity to said fastening striking opening and said forward anchoring portion of said anchoring member is engaged in said engaged slot, through an intermediate position, where, via an abutting engagement of said forcing portion with said short leg, said short leg is moved downwardly to compress said return spring to generate the return energy, and where said anchoring member is moved with said handle for being brought upwardly and rearwardly to engagingly move said striking member and said long leg of said torsion spring upwardly to gradually increase a loading of said torsion spring for said striking member, to a striking position, where said anchoring member is disengaged from said engaged slot of said striking member, and said torsion spring is freed to release a biasing energy to move said striking member downward toward said fastener striking opening, and such that, during a pivotal movement of said handle from the striking position to the ready position, said return spring is freed to release the return energy to urge said energy storing assembly upwardly and to cause the pivot movement of said handle and said anchoring member about said pivot axle and an upward movement of said long leg and said striking member to make a sliding engagement of said striking member with said forward anchoring portion of said anchoring member in the up-and-down direction, while said biasing member is loaded to accumulate a biasing force that urges said anchoring member to be engaged in said engaged slot.