Patent Publication Number: US-10766125-B2

Title: Ratchet screwdriver

Description:
The present invention is a Continuation-In-Part application of applicant&#39;s former application with the application Ser. No. 15/721,737, filed on Sep. 30, 2017. 
     BACKGROUND OF THE INVENTION 
     Field Of The Invention 
     U.S. Pat. No. 9,278,435 is one previous invention of the present inventors&#39;, which discloses and comprises a mounting seat  10 , a driving shaft  20 , four pawls  30 , four springs  40 , a fixing ring  50 , a control member  60 , a bead  70 , a positioning spring  71 , a C-clip  80  and a clipping member  81 . The rear side of the mounting seat  10  is connected with a handle (not shown) and has a space  11  defined in the front side thereof. Two first slot  112  and two second slots  113  are defined in the inside of the space  11 . The first and second slots  111 ,  113  are located symmetrically in opposite directions to each other. Each of the first slots  111  has a first hole  112  defined in the inner portion thereof, and each of the second slots  113  has a second hole  114  defined in the inner portion thereof. A passage  12  is defined through the mounting seat  10  and has a smaller diameter. A reception hole  13  is defined in the wall of the mounting seat  10 . The mounting seat  10  has two fixing members  14  and four fixing slots  15  defined in the front side thereof. A block  16  extends from the outside of the mounting seat  10  and located in opposite to the reception hole  13 . 
     The driving shaft  20  has a ratchet portion  21  which has a larger outer diameter and is located in the space  11 . The ratchet portion  21  has multiple teeth and concavities which are located alternatively to the teeth. A section  22  with a smaller diameter extends from the rear end of the driving shaft  20  and is rotatably inserted through the passage  12 . A groove  23  is defined in the outer periphery of the rear end of the driving shaft  20  and located beyond the mounting seat  10 . A working end  24  is formed on the front end of the driving shaft  20  and has a polygonal recess such as a rectangular recess or a hexagonal recess, so as to be connected with a driving member, a bolt, a nut, a socket or a connection rod. An annular slot  25  is defined in the outer periphery of the driving shaft  20 . 
     Four pawls  30  are respectively located in the first and second slots  111 ,  113 , and each pawl  30  has a bottom insertion  31  and a top insertion  32  extending from two ends of one side thereof. The bottom insertions  31  of the pawls  30  in the first slots  111  are pivotably inserted into the first holes  112  so that each of the pawls  30  is pivotable to engage the other side thereof with one of the concavities of the ratchet portion  21 . Therefore, the driving shaft  20  is driven to rotate counter clockwise by rotating the mounting seat  10  by the engagement between the pawls  30  in the first slots  111  and the ratchet portion  21  of the driving shaft  20 . The bottom insertions  31  of the pawls  30  in the second slots  113  are pivotably inserted into the second holes  114  so that each of the pawls  30  is pivotable to engage the other side thereof with one of the concavities of the ratchet portion  21 . Therefore, the driving shaft  20  is driven to rotate clockwise by rotating the mounting seat  10  by the engagement between the pawls  30  in the second slots  113  and the ratchet portion  21  of the driving shaft  20 . 
     Four springs  40  are respectively located in the two first slots  111  and the two second slots  113  and provide a force to pivot the pawls  30  to engage with the ratchet portion  21 . The springs  40  in the first slots  111  each are biased between the inside of the first slot  111  and the pawl  30  corresponding thereto, and the springs  40  in the second slots  113  each are biased between the inside of the second slot  113  and the pawl  30  corresponding thereto. By the force from the springs  40 , the four pawls  30  are pivoted and engaged with the concavities of the ratchet portion  21 . 
     When the driving shaft  20  is rotated counter clockwise, the teeth of the ratchet portion  21  drive the pawls  30  in the first slots  111  to compress the springs  40  on respective insides of the pawls  30  so that the driving shaft  20  is freely rotated. When the driving shaft  20  is rotated clockwise, the teeth of the ratchet portion  21  drive the pawls  30  in the second slots  113  to compress the springs  40  on respective insides of the pawls  30  so that the driving shaft  20  is freely rotated. 
     The fixing ring  50  is a ring-shaped member and is connected to the front side of the mounting seat  10 , and has four through holes  51 , two apertures  52  and four protrusions  53 . The top insertions  32  of the four pawls  30  are pivotably inserted into the four through holes  51 . The two fixing members  14  are inserted into the two apertures  52 . The four protrusions  53  are engaged with the four fixing slots  15 . 
     The control member  60  is rotatably mounted to the mounting seat  10  and has a mounting hole  61  defined therethrough and the driving shaft  20  rotatably extends through the mounting hole  61 . Two control plates  62  symmetrically extend from the inner periphery of the mounting hole  61 . When the control member  60  is rotated clockwise, the two control plates  62  pivot the two pawls  30  in the second slots  113  to compress the springs  40  and remove the two pawls  30  in the second slots  113  from the concavities of the ratchet portion  21 , so that the driving shaft  20  is freely rotated counter clockwise relative to the mounting seat  10 . 
     When the control member  60  is rotated counter clockwise, the two control plates  62  pivot the two pawls  30  in the first slots  111  to compress the springs  40  and remove the two pawls  30  in the first slots  111  from the concavities of the ratchet portion  21 , so that the driving shaft  20  is freely rotated clockwise relative to the mounting seat  10 . The control member  60  has three positioning slots  63  and a restriction slot  64  defined therein. The block  16  is movable in the restriction slot  64 . When the block  16  contacts one end of the restriction slot  64 , the two control plates  62  remove the two pawls  30  in the first slots  111  from the concavities of the ratchet portion  21 . When the block  16  contacts the other end of the restriction slot  64 , the two control plates  62  remove the two pawls  30  in the second slots  113  from the concavities of the ratchet portion  21 . The bead  70  is axially and movably located in the reception hole  13 . The positioning spring  71  is located in the reception hole  13  and biases the bead  70  outward to be engaged with one of the positioning slots  63 , so as to position the control member  60  at a first position where the driving shaft  20  is freely rotated counter clockwise, a second position where the driving shaft  20  cannot rotate freely, and a third position where the driving shaft  20  is freely rotated clockwise. 
     The C-clip  80  is engaged with the groove  23  of the driving shaft  20  and restricts the driving shaft  20  from being separated from the front side of the mounting seat  10 . The clipping member  81  is engaged with the annular slot  25  of the driving shaft  20  to restrict the control member  60  from being separated from the front side of the mounting seat  10 . 
     The disadvantages of the above-mentioned previous patent are: 1) the two pawls  30  are pivoted in the first slots  111  and second slots  113  by bottom insertion  31  and top insertion  32  inserting in the first hole  112  and second hole  114  respectively so as to be pivotable to engage with the ratchet portion  21 , but the pawl  30  only use their distal ends to engage one concavity between two teeth of the ratchet portion  21 , so the drive torque is very lower; and 2) the bottom insertion  31  and top insertion  32  of the pawls  30  are in plate shape, so that they are unstable when insert in the first hole  112  and second hole  114 . 
     The present invention intends to provide a ratchet driving device for a ratchet screwdriver to improve the shortcomings of the prior arts mentioned above. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a ratchet screwdriver and comprises a mounting seat, a fixing ring, a control member, a driving shaft, two pawls, two springs, a fixing ring, a control member, a bead, a positioning spring and a bolt. The mounting seat has a front with a first slot, a second slot, a first extension slot, a second extension slot, a passage, a first hole and a second hole. The driving shaft has a ratchet portion. Each pawl is biased by one spring so as to be engaged with the ratchet portion. The control member is rotatably mounted to the mounting seat and the driving shaft to pivot the pawls to switch to engage or disengage with the ratchet portion. 
     The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of the ratchet screwdriver of the present invention; 
         FIG. 2  is a perspective view to show the mounting seat of the ratchet screwdriver of the present invention; 
         FIG. 3  is a plane view to show the front side of the mounting seat of the ratchet screwdriver of the present invention; 
         FIG. 4  is a perspective view to show the rear side of the control member of the ratchet screwdriver of the present invention; 
         FIG. 5  is a perspective view to show a partial combination of the control member of the ratchet screwdriver of the present invention; 
         FIG. 6  is a perspective view to show a complete combination of the control member of the ratchet screwdriver of the present invention; 
         FIG. 7  is a front end view of the control member of the ratchet screwdriver of the present invention; 
         FIG. 8  is a cross sectional view taken along line  8 - 8  in  FIG. 7 ; 
         FIG. 9  is a side view of the control member of the ratchet screwdriver of the present invention; 
         FIG. 10  is a cross sectional view taken along line  10 - 10  in  FIG. 9 ; 
         FIG. 11  is a cross sectional view taken along line  11 - 11  in  FIG. 9 ; 
         FIG. 12  shows an exploded view of a second embodiment of the ratchet screwdriver of the present invention; 
         FIG. 13  shows an exploded view of a third embodiment of the ratchet screwdriver of the present invention; 
         FIG. 14  is a perspective view to show the mounting seat of the third embodiment of the ratchet screwdriver of the present invention; 
         FIG. 15  is a front end view of the mounting seat of the third embodiment of the ratchet screwdriver of the present invention; 
         FIG. 16  is a side view of the third embodiment of the ratchet screwdriver of the present invention; 
         FIG. 17  is a cross sectional view taken along line  17 - 17  in  FIG. 16 , and 
         FIG. 18  is a cross sectional view taken along line  18 - 18  in  FIG. 16 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 to 11 , the ratchet screwdriver of the present invention comprises a mounting seat  10 , a driving shaft  20 , two pawls  30 , two springs  40 , a fixing ring  50 , a control member  60 , a bead  70 , a positioning spring  71  and a bolt  80  having a screwed portion  81 . The rear side of the mounting seat  10  is connected with a handle (not shown) and has a front portion  11  defined in the front side thereof. A first slot  111 , a second slot  114 , a first extension slot  113  and a second extension slot  116  are defined in the inside of the front portion  11 , i.e. they recessed from the front end of the front portion  11 . The first and second slots  111 ,  114  are located symmetrically in opposite directions to each other. The first and second extension slots  113 ,  116  are located symmetrically in opposite directions to each other. The first slot  111  has a first hole  112  defined in the inner portion thereof, and the second slot  114  has a second hole  115  defined in the inner portion thereof. The first extension slot  113  with an inclined face is connected with one end of the first slot  111 . The second extension slot  116  with an inclined face is connected with one end of the second slot  114 . The first and second holes  112 ,  115  are located symmetrically in opposite directions to each other, and they are located at the connection of the first slot  111  and the first extension slot  113 , and the connection of the second slot  114  and the second extension slot  116  respectively. A pivotal portion  14  protrudes from the central area of the front end of the front portion  11 . A fixing rod  15  protrudes from the front end of the front portion  11  and locates at lateral side of the pivotal portion  14  with a distance. A passage  12  is defined through the mounting seat  10  and has a smaller diameter, and coaxially extending through the pivotal portion  14 . A reception hole  13  is defined in one side of outer periphery of the front portion  11  of the mounting seat  10 . A recessed slot  16  is recessed from another side of outer periphery of the front portion  11  and located in opposite to the reception hole  13 , and has one open end located at the front end of the front portion  11 . 
     A circular receiving space  200  is recessed from the central area of the rear end of the driving shaft  20 . The receiving space  200  is for receiving the front portion  11  of the mounting seat  10 . A ratchet portion  21  is circularly distributed on the inner periphery of the receiving space  200 . A pivotal hole  22  is recessed from the bottom of the receiving space  200  and is for pivotably receiving the pivotal portion  14 . A screwed hole  24  is recessed from the bottom  23  of the pivotal hole  22 . The ratchet portion  21  has multiple teeth and concavities which are located alternatively to the teeth. A function end  25  is defined on the front end of the driving shaft  20 , and has a polygonal recess such as a rectangular recess or a hexagonal recess, or has a polygonal rod such as square rod, so as to be connected with a driving member, a bolt, a nut, a socket or a connection rod. 
     Two pawls  30  are respectively located in the first and second slots  111 ,  114  and are located symmetrically in opposite directions to each other with respect to the mounting seat  10 . One front end of each pawl  30  has an engaging portion  31  with multiple teeth for engaging with the teeth of the ratchet portion  21 . Each pawl  30  has a cylindrical pivot  32  with two ends protruding from two lateral sides of the rear end of each pawl  30 . The rear end of each pawl  30  extends a contact portion  33 . The cylindrical pivots  32  of the pawls  30  in the first and second slots  111 ,  114  are respectively pivotably inserted into the first and second holes  112 ,  115 , so that the two pawls  30  are rotatable to engage with the teeth of the ratchet portion  21  by their teeth. The engaging portions  31  of the two pawls  30  are respectively located in the first and second slots  111 ,  114 , and the contact portions  33  of the two pawls  30  are respectively located in the first and second extension slot  113 ,  116 . Therefore, the driving shaft  20  is driven to rotate counter clockwise or clockwise by rotating the mounting seat  10  by the engagement between the teeth of the engaging portion  31  of the pawls  30  in the first and second slots  111 ,  114  and the teeth of the ratchet portion  21  of the driving shaft  20 . 
     Two springs  40  are respectively located in the first and second slots  111 ,  114  and provide elastic forces to pivot the two pawls  30  to engage with the teeth of the ratchet portion  21  by the teeth of their engaging portions  31 . The spring  40  in the first slot  111  is biased between the inside of the first slot  111  and one pawl  30  corresponding thereto, and the spring  40  in the second slot  114  is biased between the inside of the second slot  114  and the other pawl  30  corresponding thereto. By the force from the springs  40 , the teeth of the engaging portions  31  of the two pawls  30  are pivoted and engaged with the teeth of the ratchet portion  21 . Two recessed holes  1110 ,  1140  are defined on lateral sides of the first and second slots  111 ,  114  for receiving one end of the two springs  40  respectively. 
     The fixing ring  50  is a ring-shaped member having one through hole  52  at central area, two apertures  51  and one positioning hole  53 . The fixing ring  50  is connected to the front side of the mounting seat  10  and is fixedly mounted on the pivotal portion  14 . The other ends of the cylindrical pivots  32  of the two pawls  30  are pivotably inserted into the two apertures  51 . The positioning hole  53  is engaged with the fixing rod  15 , so that the fixing ring  50  can&#39;t rotate with respect to the mounting seat  10 . 
     The ring shaped control member  60  with an outer periphery defined multiple teeth  600  thereon is rotatably mounted on the outer periphery of the front portion  11  of the mounting seat  10  and has a mounting hole  61  defined therethrough. A circular flange  100  protrudes from the outer periphery of the rear end of the front portion  11 . The control member  60  is limited between the circular flange  100  and the rear end of the driving shaft  20  so that he control member  60  can&#39;t be apart from the mounting sear  10 . A push portion  63  extends from one side of the inner wall of the inner space  62  of the mounting hole  61 , and the distal portion of the push portion  63  inserts into the recessed slot  16 . When the control member  60  is rotated counter clockwise with respect to the mounting seat  10 , the push portion  63  pivots the contact portion  33  of one pawl  30  in the first slot  111  to compress the spring  40  and remove the teeth of engaging portion  31  of the pawl  30  in the first slot  111  from the teeth of the ratchet portion  21 , so that the driving shaft  20  is freely rotated clockwise relative to the mounting seat  10 . When the control member  60  is rotated clockwise with respect to the mounting seat  10 , the push portion  63  pivots the contact portion  33  of one pawl  30  in the second slot  114  to compress the spring  40  and remove the teeth of engaging portion  31  of the pawl  30  in the second slot  114  from the teeth of the ratchet portion  21 , so that the driving shaft  20  is freely rotated counter clockwise relative to the mounting seat  10 . 
     Another side of the inner wall of the inner space  62  of the mounting hole  61  of the control member  60  opposite to the push portion  63  has three positioning slots  64  defined therein. The push portion  63  is movable in the recessed slot  16 . When the control member  60  is rotated clockwise with respect to the mounting seat  10  and from a second position to a first position, the push portion  63  contacts one end of the recessed slot  16  and pivots the pawl  30  in the second slot  114  to compress the spring  40 , and remove the teeth of the engaging portion  31  of one pawl  30  in the second slot  114  from the teeth of the ratchet portion  21 , so that the driving shaft  20  is freely rotated counter clockwise relative to the mounting seat  10 . When the control member  60  is rotated counter clockwise with respect to the mounting seat  10  and from the second position to a third position, the push portion  63  contacts another end of the recessed slot  16  and pivots the pawl  30  in the first slot  111  to compress the spring  40 , and removes the teeth of the engaging portion  31  of the pawl  30  in the first slot  111  from the teeth of the ratchet portion  21 , so that the driving shaft  20  is freely rotated clockwise relative to the mounting seat  10 . When the control member  60  is at the second position with respect to the mounting seat  10 , the teeth of the engaging portion  31  of the two pawls  30  engage with the teeth of the ratchet portion  21 , so that the driving shaft  20  is rotatable clockwise and counter clockwise together with the mounting seat  10 . The bead  70  is axially and movably located in the reception hole  13 . The positioning spring  71  is located in the reception hole  13  and biases the bead  70  outward to be engaged with one of the three positioning slots  64 , so as to position the control member  60  at the first position where the driving shaft  20  is freely rotated counter clockwise, the second position where the driving shaft  20  cannot rotate freely, and the third position where the driving shaft  20  is freely rotated clockwise. 
     The bolt  80  is inserted into the passage  12  and screwed with the screwed hole  24  of the driving shaft  20  by its screwed portion  81 , so as to restrict the driving shaft  20  from being separated from the mounting seat  10 . A contact face  82  is defined on rear end of the screwed portion  81  is for contacting with the bottom  23  of the pivotal hole  22 . The distal end of the pivotal portion  14  contacts the bottom  23  of the pivotal hole  22 . 
     As shown in  FIG. 12  which shows the second embodiment of the present invention wherein the mounting seat  10  has no the pivotal portion  14 , the fixing rod  15  and the fix ring  50  shown in  FIG. 1 . 
     As shown in  FIGS. 13 to 15  which show the third embodiment of the present invention wherein the difference is that there is no recessed slot  16  shown in  FIG. 1 , the first and second extension slot  113 ,  116  invaginate connect with lateral sides of the first and second slots  111 ,  114 , the contact portion  33  of each pawl  30  is positioned between the engaging portion  31  and the pivot  32 , and two push portions  630  symmetrically protrudes from the wall of the mounting hole  61  and directs to the central of the inner space  62  for pushing the contact portions  33  in the first and second slots  111 ,  114  respectively. 
     As shown in  FIGS. 16 to 18 , when the control member  60  is rotated counter clockwise with respect to the mounting seat  10  to the first position, the push portion  630  contacts the contact portion  33  and pivots the pawl  30  in the first slot  111  to compress the spring  40 , and removes the teeth of the engaging portion  31  of the pawl  30  in the first slot  111  from the teeth of the ratchet portion  21 , so that the driving shaft  20  is freely rotated clockwise relative to the mounting seat  10 . When the control member  60  is rotated clockwise with respect to the mounting seat  10  to the third position, the push portion  630  contacts the contact portion  33  and pivots the pawl  30  in the second slot  114  to compress the spring  40 , and removes the teeth of the engaging portion  31  of the pawl  30  in the second slot  114  from the teeth of the ratchet portion  21 , so that the driving shaft  20  is freely rotated counter clockwise relative to the mounting seat  10 . When the control member  60  is at the second position with respect to the mounting seat  10 , the teeth of the engaging portions  31  of the two pawls  30  engage with the teeth of the ratchet portion  21  together, so that the driving shaft  20  is rotatable clockwise and counter clockwise together with the mounting seat  10 . 
     The advantages of the present invention are as followings: 
     1. the two pawls  30  received in the first and second slots  111 ,  114  each is pressed by an elastic force of one spring  40  and has an engaging portions  31  with multiple teeth at lateral side, so that the engaging portions  31  engage with the ratchet portion  21  by multiple teeth, and so that the screwdriver has more effective driving torque; 
     2. the two pawls  30  have cylindrical pivots  32  pivotably inserted into the first and second holes  112 ,  115 , and apertures  51  of the fixing ring  50 , so that the two pawls  30 , the fixing ring  50  and the mounting seat  10  are mounted stably; 
     3. The pivotal portion  14  inserts into the pivotal hole  22  and the through hole  52 , and the fixing ring  50  is pivotally received in the receiving space  200 , and 
     4. The bolt  80  is inserted into the passage  12  and screwed with the screwed hole  24  of the driving shaft  20  by its screwed portion  81 . 
     While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.