Patent Publication Number: US-2012031239-A1

Title: Retractable screwdriver

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a screwdriver, and more particularly to a retractable screwdriver with a precision ratchet positioning assembly. 
     2. Description of the Related Prior Art 
     Taiwan Patent Publication No. 586472 discloses “A structure of a precision screwdriver” related to a precision screwdriver, which comprises a sleeve at the top end of the connecting end of the screwdriver. The sleeve comprises a tube rod which has an axial through hole to receive a magnetic element therein to divide the tube rod into two sections, a front end and a rear end. A pair of ratable bits are inserted into the hole of the tube rod and secured by the magnetic element in the hole while the screwdriver is in use. 
     However, the screwdriver is limited to the two bits only if the object to be is worked on has a difference size. Thus, the screwdriver is useless. Further, the length of the bit is fixed. Should the object is located at a deeper location, the bit will have difficulty to reach. 
     Still further, many of the precision screwdrivers may not have a ratchet gear because the screwdriver is designed for a small object, such as small size screws. The ratchet gear may cause a counter torque when in operation, and may not tighten the screw. 
     SUMMARY OF THE INVENTION 
     In view of the above shortcomings, a retractable screwdriver with a precision ratchet positioning assembly is invented and presented for a patent application. The retractable screwdriver comprises a base, a first tube, a first transmission rod, a second tube, a second transmission rod, a rod member, and a rotating member. The base comprises a receptacle and a through hole. The receptacle comprises a ratchet positioning assembly therein. The base further comprises a connecting portion. The first tube is fitted on the base. The first transmission rod is inserted into the through hole of the base. The first transmission rod has a blind hole therein. The first transmission rod has a first end and an opposing second end. The first end of the first transmission rod is provided with a gear shaft to mesh with a ratchet gear. The second end of the first transmission rod has a first engaging portion. The second tube has an opening to engage with the connecting portion of the base. The second transmission rod is inserted into the opening of the second tube. The second transmission rod has a through hole therein. The second transmission rod has a first end and an opposing second end. The first end of the second transmission rod has a second engaging portion to engage with the first engaging portion of the first transmission rod. The rod member is inserted into the through hole of the second transmission rod and the blind hole of the first transmission rod. The rotating member is fitted on the base. The rotating member has a through hole for the first transmission rod to insert therethrough. 
     Preferably, the second end of the second transmission rod has a threaded portion with a cut-off portion, and the threaded portion is connected with a tightening nut. 
     Preferably, the rod member has a first end and an opposing second end. The first end of the rod member has a circular groove to receive a washer. The second end of the rod member has a positioning trough therein. 
     Preferably, the ratchet positioning assembly comprises a circular positioning portion, at least six positioning recesses, two pawls and two elastic elements. The positioning portion is formed around an inner wall of the receptacle. The six positioning recesses are disposed on the positioning portion and divided into two sets. The elastic elements engage with the pawls, respectively. Each of the pawls comprises a pin pivoted in the receptacle. The rotating member further comprises two positioning pins and two push studs. Each of the positioning pins has a positioning protrusion to engage with a corresponding positioning recess. 
     Preferably, the base has a plurality of spaced troughs around an outer wall thereof and slots each disposed between every two adjacent troughs. The first tube comprises an outlet corresponding to the troughs and an elastic block corresponding to the slots. 
     Preferably, the rotating member comprises a knob and a cap disposed in the knob. The cap meshes with the gear shaft of the first transmission rod. 
     It is the primary object of the present invention to provide a retractable screwdriver, which comprises a base for bits to be stored therein, and a ratchet positioning assembly to secure the base with a first tube to minimize the size of the screwdriver, enabling to replace different bits. 
     It is another object of the present invention to provide a retractable screwdriver, which comprises a first engaging portion of a first transmission rod to engage with a second engaging portion of a second transmission rod. The two-section engagement of the two engaging portions enhances the strength of the transmission rods and eliminates the deformation of the material caused by the lengthy problem of the transmission rod. 
     It is still another object of the present invention to provide a retractable screwdriver, which comprises a ratchet positioning assembly disposed on top of the base for the user to monitor the movement with ease. 
     It is still another object of the present invention to provide a retractable screwdriver, which comprises a gear shaft at an upper end of the first transmission rod. The gear shaft extends into the cap and meshes with the gear. Thus, the cap is able to control rotation of the first transmission rod and also to eliminate the possible swing back torque force. 
     It is a further object of the present invention to provide a retractable screwdriver, which provides a number of troughs on the base to receive bits therein. 
     It is still a further object of the present invention to provide a retractable screwdriver, wherein the length of the rod member is adjustable in the first transmission rod and the second transmission rod. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of the present invention; 
         FIG. 2  is a perspective view of the present invention; 
         FIG. 3  is a cross sectional view of  FIG. 2 ; 
         FIG. 4  is a sectional view taken along line A-A of  FIG. 3 ; 
         FIG. 5  is another sectional view taken along line B-B of  FIG. 3 ; 
         FIG. 6  is a view similar to  FIG. 4 , showing a push stud forced by pawls and elastic elements to move so that positioning protrusions are switched to a new position and seating in another recesses; 
         FIG. 7  is a perspective view showing a bit taken out from the outlet of the first tube; 
         FIG. 8  is a perspective view showing the screwdriver operated by fingers; and 
         FIG. 9  is a cross sectional view showing adjustment of the rod member to extend within the through hole and the blind hole. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFRRED EMBODIMENT 
     As shown in  FIGS. 1 ,  2  and  3 , a retractable screwdriver of the present invention comprises a base  1 , a first tube  2 , a first transmission rod  3 , a second tube  4 , a second transmission rod  5 , a rod member  6  and a rotating member  7 . 
     The base  1  comprises a receptacle  11  and a through hole  12  at an upper end thereof. The receptacle  11  comprises a ratchet positioning assembly therein, as shown in  FIG. 4 . The ratchet positioning assembly comprises a circular positioning portion  13 , six positioning recesses  14 , two pawls  15 , and two elastic elements  16 . The positioning portion  13  is formed around an inner wall of the receptacle  11 . The six positioning recesses  14  are disposed on the positioning portion  13  and divided into two sets. The two elastic elements  16  hold against the two pawls  15 , respectively. Each pawl  15  comprises a pin  151  to be pivoted in the receptacle  11 . The base  1  has a number of troughs  17  equally spaced on an outer wall thereof. The troughs  17  are adapted to receive bits A therein. The base  1  has slots  18  each disposed between two adjacent troughs  17 . The base  1  further comprises a connecting portion  19  extending downward from the base  1 . 
     The first tube  2  fitted onto the base  1  comprises a longitudinal outlet  21  corresponding to the troughs  17  of the base  1  and an elastic block  22  corresponding to the slots  18 . The elastic block  22  is engaged in one of the slots  18 , as shown in  FIG. 5 . 
     The first transmission rod  3  is inserted into the through hole  12  of the base  1 , and has a blind hole  31  therein. The first transmission rod  3  has a first end and a second end opposite to the first end. A gear shaft  32  is provided at the first end to mesh with teeth  34  of a ratchet gear  33 . The teeth  34  are confined by the pawls  15  from moving freely. The second end of the first transmission rod  3  has a first engaging portion  35 . 
     The second tube  4  has an opening  41  for the connecting portion  19  of the base  1  to be secured thereat. 
     The second transmission rod  5  is inserted into the opening  41  of the second tube  4 . The second transmission rod  5  has a through hole  51  therein. The second transmission rod  5  has a first end and a second end opposite to the first end. The first end has a second engaging portion  52  to engage with the first engaging portion  35  of the first tube  3  in a rotating manner. The second end of the second transmission rod  5  has a cut-off portion  53  and a threaded portion  54 . The threaded portion  54  is connected with a tightening nut  55 . 
     The rod member  6  is inserted into the through hole  51  of the second transmission rod  5  and the blind hole  31  of the first transmission rod  3 . The rod member  6  has a first end and a second end opposite to the first end. The first end of the rod member  6  has a circular groove  61  to receive a washer  62  therein. The second end of the rod member  6  has a positioning trough  63  for one of the bits A to be secured therein. 
     The rotating member  7  is fitted on top of the base  1  and has a through hole  71  for the first transmission rod  3  to insert therethrough. The rotating member  7  comprises two positioning pins  72  and two push studs  73 . Each positioning pin  72  comprises a positioning protrusion  74  thereon. The positioning protrusion  74  is to engage with one of the positioning recesses  14  of the positioning portion  13  of the receptacle  11 . Each push stud  73  is engaged with the pawl  15  so as to adjust the moving direction of the ratchet gear  33 . The rotating member  7  further comprises a knob  75  with a cap  76  secured on top thereof. The cap  76  is formed with inner teeth  761  for meshing with the gear shaft  32  of the first transmission rod  3 . 
     To operate the present invention, as shown in  FIG. 1  and  FIG. 6 , the rotating member  7  is turned to force the positioning protrusions  74  of the positioning pins  72  to move into different recesses  14 , which will adjust the turning direction as required. (This is a traditional technique to control the rotation of the ratchet and will not be described further.) Whereas, one of the push stubs  73  will force the pawl  15  to disengage from the teeth  34  of the ratchet gear  33 , thus the ratchet gear  33  may rotate in a clockwise direction. Then, the first tube  2  is turned, which forces the elastic block  22  to disengage from the slot  18  of the base  1  and the first tube  2  is free to turn until the outlet  21  is aligned with one of the troughs  17  where a desired bit A is stored therein, thus the bit A is able to be taken out of the trough  17 , as shown in  FIG. 7 . Upon the bit A is taken away, the first tube  2  is turned to move the outlet  21  away from its current recess  14  to seal the trough  17 , and the elastic block  22  is seating into one of the slots  18  again. The bit A is then inserted into the positioning trough  63  of the rod member  6 , as shown in  FIG. 3 . Whereby sliding the through hole  51  of the second transmission rod  5  and the blind hole  31  of the first transmission rod  3 , the length of the rod member  6  may be adjusted, as shown in  FIG. 9 . When the desired length of the rod member  6  is done, the tightening nut  55  of the second transmission rod  5  is turned to fix the length of the rod member  6 . 
     To hold the second tube  4  with the user&#39;s thumb and middle finger, as shown in  FIG. 8 , with the point finger pressing the cap  76  of the knob  75 , the bit A will be engaged with the screw B. By turning the second tube  4 , the first tube  2  links the first transmission rod  3 , the second transmission rod  5  and the rod member  6  to turn the screw B in a clockwise direction. During the turning movement, both the first engaging portion  35  of the first transmission rod  3  and the second engaging portion  55  of the second transmission rod  5  transmit the turning force which reinforces the strength of the first transmission rod  3  and the second transmission rod  5 . The higher position of the ratchet gear  33  provides a better view for the user to monitor the movement. The engagement of the gear shaft  32  of the first transmission rod  3  and the inner teeth  761  of the cap  76  prevents the ratchet gear from reversing. 
     The foregoing description of the specific embodiments will fully reveal the nature of this invention that others can, by applying current knowledge, readily modify, adapt for various applications, such specific embodiment without departing from the general concept, therefore such adaptations of the modifications should be and intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.