Patent ID: 7237458
Filing Date: 2007-07-03
Classification: B25B,B25G

Abstract:
1. A ratchet screwdriver comprising: a screwdriver body extending along a screwdriver axis and having a rear end that is formed with a guide tube, a front end that is formed with a front seat connected fixedly to said guide tube, and an axial hole formed in said guide tube and extending into said front seat, said front seat having a magazine-accommodating space that is communicated with said axial hole and that is disposed in front of said guide tube; a bit magazine unit disposed removably within said magazine-accommodating space and including a magazine body extending along a magazine axis and journalled within said magazine-accommodating space, said magazine axis being parallel to said screwdriver axis, said magazine body having a plurality of axially extending bit slots that are formed therethrough and that are disposed around said magazine axis, a selected one of said bit slots being aligned with said axial hole in said screwdriver body, and a plurality of bits received respectively within said bit slots in said screwdriver body; a driving rod disposed movably axially within said axial hole in said screwdriver body and including a driving end projecting rearwardly from said guide tube, and a bit-coupling end opposite to said driving end, a magnetically attracting member disposed fixedly on said bit-coupling end and attached magnetically to a rear end of a corresponding one of said bits disposed within said selected one of said bit slots in said magazine body, said driving rod being movable relative to said screwdriver body between a front limit position, where the corresponding one of said bits is ejected from said selected one of said bit slots for performing a screw-driving operation, and a rear limit position, where the corresponding one of said bits is received entirely within said selected one of said bit slots; and a ratchet unit disposed on said front seat and disposed in front of said magazine-accommodating space in said front seat, said ratchet unit including wherein said ratchet unit further includes a second pawl having a plurality of retaining teeth, and a second resilient member for biasing said retaining teeth of said second pawl toward said ratchet teeth of said ratchet wheel, wherein engagement between said retaining teeth of said first pawl and said ratchet teeth of said ratchet wheel allowing for co-rotation of said ratchet wheel and said screwdriver body in a direction, and wherein engagement between said retaining teeth of said second pawl and said ratchet teeth of said ratchet wheel allowing for co-rotation of said ratchet wheel and said screwdriver in an opposite direction; wherein said rotary cover has a driving portion that is in slidable contact with said first and second pawls, said rotary cover being operable so that said driving portion of said rotary cover rotates each of said first and second pawls to change from an engagement position to a disengagement position, said driving portion having an annular outer surface that is eccentric with respect to said screwdriver axis and that has a pushing section and a release section, which is located nearer to said screwdriver axis than said pushing section, each of said first and second pawls being disposed at said engagement position so as to engage said retaining teeth of a corresponding one of said first and second pawls with said ratchet teeth of said ratchet wheel when said release section of said annular outer surface of said driving portion of said rotary cover comes into contact with the corresponding one of said first and second pawls, each of said first and second pawls being disposed at said disengagement position so as to remove said retaining teeth of the corresponding one of said first and second pawls from said ratchet teeth of said ratchet wheel when said pushing section of said annular outer surface of said driving portion of said rotary cover comes into contact with the corresponding one of said first and second pawls; wherein said positioning seat has a stepped hole, said stepped hole having a small-diameter portion disposed in proximity to said magazine-accommodating space in said front seat, and a large-diameter portion disposed in front of said small-diameter portion and having a diameter greater than that of said small-diameter portion, said positioning seat further having a shoulder disposed between said small-diameter and large-diameter portions of said stepped hole, said ratchet wheel being disposed within said large-diameter portion of said stepped hole in said positioning seat, said shoulder being formed with two first pivot holes, said positioning seat further having a front end surface that is formed with a recess, said ratchet unit further including a position-limiting plate that is fitted within said recess in said front end surface of said positioning seat and that is sleeved rotatably on said ratchet wheel, said position-limiting plate being formed with two second pivot holes aligned respectively with said first pivot holes in said shoulder of said positioning seat, each of said first and second pawls further having front and rear sides, each of said first and second pawls further having a first pin that is formed integrally with said rear side of a corresponding one of said first and second pawls and that is disposed rotatably within a corresponding one of said first pivot holes in said shoulder of said positioning seat, and a second pin that is formed integrally with said front side of the corresponding one of said first and second pawls and that is disposed rotatably within a corresponding one of said second pivot holes in said position-limiting plate.