RATCHET SCREWDRIVER

摘要

A ratchet screwdriver includes a mounting seat, a fixing ring, a control member, a driving shaft, four pawls and four springs. The mounting seat has a space, two first slots and two second slots. A passage is defined through the mounting seat. The first slots each have a first hole and the second slots each have a second hole. The driving shaft has a ratchet portion located in the space. The four pawls are biased by the four springs so as to be engaged with the ratchet portion. The fixing ring is connected to the mounting seat and the four pawls are pivotably connected to the fixing ring. The control member is rotatably mounted to the mounting seat and the driving shaft. The control member has two control plates to pivot the pawls to disengage from the ratchet portion of the driving shaft.

主权项

1. A ratchet screwdriver comprising:
a mounting seat having a space defined in a front side thereof, two first slot and two second slots defined in an inside of the space, the first and second slots located symmetrically in opposite directions to each other, each of the first slots having a first hole defined in an inner portion thereof, each of the second slots having a second hole defined in an inner portion thereof, a passage defined through the mounting seat, a reception hole defined in a wall of the mounting seat, the mounting seat having two fixing members and four fixing slots defined in the front side thereof, a block extending from an outside of the mounting seat and located in opposite to the reception hole; a driving shaft having a ratchet portion which is located in the space, the ratchet portion having multiple teeth and concavities which are located alternatively to the teeth, a section extending from a rear end of the driving shaft and rotatably inserted through the passage, a groove defined in an outer periphery of the rear end of the driving shaft and located beyond the mounting seat, a working end formed on a front end of the driving shaft and adapted to be connected with a driving member, an annular slot defined in the outer periphery of the driving shaft; four pawls respectively located in the first and second slots, each pawl having a bottom insertion and a top insertion extending from two ends of one side thereof, the bottom insertions of the pawls in the first slots pivotably inserted into the first holes so that each of the pawls is pivotable to engage the other side thereof with one of the concavities of the ratchet portion, the driving shaft being driven to rotate counter clockwise by rotating the mounting seat by engagement between the pawls in the first slots and the ratchet portion of the driving shaft, the bottom insertions of the pawls in the second slots pivotably inserted into the second holes so that each of the pawls is pivotable to engage the other side thereof with one of the concavities of the ratchet portion, the driving shaft being driven to rotate clockwise by rotating the mounting seat by engagement between the pawls in the second slots and the ratchet portion of the driving shaft; four springs respectively located in the two first slots and the two second slots and providing a force to pivot the pawls to engage with the ratchet portion, when the driving shaft is rotated counter clockwise, the teeth of the ratchet portion drive the pawls in the first slots to compress the springs on respective insides of the pawls so that the driving shaft is freely rotated; a fixing ring connected to the front side of the mounting seat and having four through holes, two apertures and four protrusions, the top insertions of the four pawls pivotably inserted into the four through holes, the two fixing members inserted into the two apertures, the four protrusions engaged with the four fixing slots; a control member rotatably mounted to the mounting seat and having a mounting hole defined therethrough and the driving shaft rotatably extending through the mounting hole, two control plates extending from an inner periphery of the mounting hole, when the control member is rotated clockwise, the two control plates drive the two pawls in the second slots to remove the two pawls in the second slots from the concavities of the ratchet portion, so that the driving shaft is freely rotated counter clockwise relative to the mounting seat, when the control member is rotated counter clockwise, the two control plates drive the two pawls in the first slots to remove the two pawls in the first slots from the concavities of the ratchet portion, so that the driving shaft is freely rotated clockwise relative to the mounting seat, the control member having three positioning slots and a restriction slot defined therein, the block being movable in the restriction slot, when the block contacts one end of the restriction slot, the two control plates remove the two pawls in the first slots from the concavities of the ratchet portion, when the block contacts the other end of the restriction slot, the two control plates remove the two pawls in the second slots from the concavities of the ratchet portion; a bead axially and movably located in the reception hole; a positioning spring located in the reception hole and biasing the bead outward to be engaged with one of the positioning slots, so as to position the control member at a first position where the driving shaft is freely rotated counter clockwise, a second position where the driving shaft cannot rotate freely, and a third position where the driving shaft is freely rotated clockwise; a C-clip engaged with the groove of the driving shaft and restricting the driving shaft from being separated from the front side of the mounting seat, and a clipping member engaged with the annular slot of the driving shaft to restrict the control member from being separated from the front side of the mounting seat.