Patent Publication Number: US-8113092-B2

Title: Push-type ratchet wrench

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to the technological field of switching a driving direction in a ratchet wrench, and more particularly to a push-type ratchet wrench, which can be easily operated and has the precise positioning effect. 
     2. Description of the Related Art 
     A ratchet wrench is a hand tool with the unidirectional driving ability, and is mainly used to screw and unscrew a bolt (nut) without the need of continuously changing the hand&#39;s posture so that the operation convenience can be obtained. The conventional ratchet wrench has a handle having a head formed with a chamber, in which a driving body with pawls formed on its outer periphery is disposed. The driving body has a fitting hole to be fit with the bolt (nut) or a fitting head to be inserted into a sleeve. The head is formed with an engaging block on a periphery on one side of the driving body in the free space. The engaging block has pawls corresponding to the driving body and is for restricting the engaging direction of the driving body. Furthermore, a control member capable of shifting the engaging block is formed on the head. The control member is typically a rotatable actuating rod, which may be rotated or swung to control the movement of the engaging block. 
     When these conventional ratchet wrenches are actually used, the positioning effect during operation is poor because the operating direction of the actuating rod and the moving direction of the engaging block are the same. That is, the actuating block is oppositely moved by the engaging block during operation, thereby influencing the operation effectiveness of the ratchet wrench. Furthermore, the size of the engaging block is not large, so the space for accommodating the actuating rod is limited and the size of the actuating rod of the control member is reduced. Thus, the too-small actuating rod causes the inconvenience for the user&#39;s operation, thereby influencing the actual operating convenience. More particularly, the control member with the too-small size may be broken due to the improper force applied during the operation process so that the lifetime thereof is shortened. 
     In view of this, a push-type ratchet wrench is developed to overcome the problems, including the uneasy operation of the ratchet wrench and the poor positioning effect, encountered in the switching operation of the ratchet wrench. 
     SUMMARY OF THE INVENTION 
     It is therefore a main object of the invention to provide a push-type ratchet wrench for switching the operating direction by the leftward/rightward pressing without the problems of the easily breaking and the uneasily actuating so that the precision of the motion and the operation convenience can be enhanced. 
     The invention achieves the above-identified object by providing a push-type ratchet wrench comprising a handle, a driving body, an engaging block and a control member. The handle has two ends. At least one of the two ends has a head. The head is formed with a chamber with an opening on one side of the head. The chamber is composed of a first accommodating slot and a second accommodating slot communicating with each other. The other side of the head opposite to the one side of the head is formed with a long slot opening communicating with the second accommodating slot. 
     The driving body is disposed in the first accommodating slot of the chamber of the head. A periphery of the driving body is formed with a series of pawls, and the driving body is for embedding and fitting with a workpiece. 
     The engaging block is disposed on one side of the driving body disposed in the first accommodating slot of the head. An internally curved surface of the engaging block is formed with pawls corresponding to the pawls of the driving body. A middle of a rear edge of the engaging block is formed with a clamping slot. Two sidewall surfaces of the clamping slot are slopped conical surfaces expanding outwards. 
     The control member is disposed in the second accommodating slot of the chamber of the head. The control member has a base disposed in the second accommodating slot and an actuating block pivotally connected to the base. The base has an inserting slot, in which the actuating block may be inserted and swung. A plurality of positioning slots is formed on a wall surface of the inserting slot. A cross slot, across which the actuating block may be placed, is formed on the base. A lower half section of the actuating block may be placed across the cross slot of the base. An upper half section of the actuating block projects out of the long slot opening of the head. The actuating block has a projecting extension inserting through the inserting slot. A positioning steel ball, which may be elastically moved by an elastic member, is disposed on the actuating block. The actuating block may be restricted relatively to the positioning slot of the base using the positioning steel ball. A hole is formed at an end portion of the projecting extension of the actuating block. An actuating sheet is embedded into the hole. The actuating sheet penetrating through the base is clamped in the clamping slot of the engaging block so that the push-type ratchet wrench that may be conveniently switched and operated is constructed. 
     The operating direction of the actuating block of the control member of the invention is perpendicular to the moving direction of the engaging block. Thus, the engaging block may be stably limited, no malfunction of the engaging block is caused during operation, and the size of the control member assembly can be enlarged. Thus, the engaging block can be easily operated, and is free from being broken due to the improperly applied force so that the lifetime thereof may be effectively lengthened. Thus, the ratchet wrench of the invention may be improved in the aspects of the precision of the motion, the operation convenience and the lifetime. 
     Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects of the present invention will become readily apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
         FIG. 1  is a stereoscopic decomposed schematic illustration showing a ratchet wrench of the invention for the description of its components and relative relationships between the components; 
         FIG. 2  is a stereoscopic decomposed schematic illustration showing the ratchet wrench of the invention at another viewing angle; 
         FIG. 3A  is a stereoscopic exterior schematic rear view showing an engaging block in the ratchet wrench of the invention; 
         FIG. 3B  is a stereoscopic exterior schematic rear view showing an engaging block in the ratchet wrench according to another embodiment of the invention; 
         FIG. 4  is a stereoscopic exterior schematic bottom view showing the ratchet wrench in a state when a head is not covered by a cover sheet; 
         FIG. 5A  is a schematic illustration showing the plane motion of the ratchet wrench of the invention, wherein a driving body is in a counterclockwise free running and forward driving state; 
         FIG. 5B  is a schematic local plane view showing the ratchet wrench of the invention for the description of the relationship between the control member and the engaging block in  FIG. 5A ; 
         FIG. 5C  is a schematically partial cross-sectional view showing the ratchet wrench of the invention for the description of the cross-sectional state taken along  5 C- 5 C of  FIG. 5B ; 
         FIG. 6A  is another schematic illustration showing the plane motion of the ratchet wrench of the invention, wherein the driving body is in a clockwise free running and reverse driving state; 
         FIG. 6B  is a schematic local plane view showing the ratchet wrench of the invention for the description of the relationship between the control member and the engaging block in  FIG. 6A ; and 
         FIG. 6C  is a schematically partial cross-sectional view showing the ratchet wrench of the invention for the description of the cross-sectional state taken along  6 C- 6 C of  FIG. 6B . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The structure of a ratchet wrench of the invention is shown in  FIGS. 1 and 2 , and includes a handle  10  having a head  11 , a driving body  20  disposed in the head  11 , an engaging block  40  for restricting the rotation of the driving body  20 , and a control member  50 , which can be pressed to control the movement of the engaging block  40 . 
     The detailed structure according to the preferred embodiment of the invention will be described with reference to  FIGS. 1 ,  2  and  4 . At least one of two ends of the handle  10  has the head  11 . The head  11  is formed with a chamber  12  with an opening toward one side. The chamber  12  is composed of a first accommodating slot  13  and a second accommodating slot  14  communicating with each other. The first accommodating slot  13  with the larger diameter can accommodate the driving body  20  and the engaging block  40 , and the second accommodating slot  14  with the smaller diameter can accommodate the control member  50 . Also, the other side of the head  11 , which is formed with the opening of the chamber  12  and opposite to the one side of the head  11 , is formed with a through opening  15  communicating with a center of the first accommodating slot  13 , and is formed with a long slot opening  16  communicating with the second accommodating slot  14 . Furthermore, a cover sheet  18  for restricting the driving body  20 , the engaging block  40  and the control member  50  is screwed to the one side of the head  11  formed with the opening of the chamber  12 . The cover sheet  18  is formed with a through hole  19  corresponding to the center of the driving body  20 . 
     A periphery of the driving body  20  disposed in the chamber  12  of the head  11  is formed with a series of pawls  21  to be meshed with the engaging block  40 . Also, the center of the driving body  20  has a fitting hole for embedding and fitting with a bolt (nut), or a polygonal rod-like fitting head  25  for inserting into a sleeve in the main embodiment of the invention. The fitting head  25  may penetrate through the through hole  19  of the cover sheet  18  screwed to the head  11 . Also, a slide hole  26  is formed on an axis of the fitting head  25 , and a side surface of the fitting head  25  is formed with an engagement hole  27  perpendicularly communicating with the slide hole  26 . An actuating rod  30  is disposed in the slide hole  26  and may slide therein. One end of the actuating rod  30  may penetrate through the through opening  15  of the head  11  of the handle  10 . Also, the actuating rod  30  is formed with a stepped slot  31  corresponding to the engagement hole  27  of the fitting head  25 . Moreover, a steel ball  32  capable of selectively partially projecting out of the engagement hole  27  is disposed in the stepped slot  31 . In addition, an elastic member  35  is disposed between the actuating rod  30  and the slide hole  26  of the fitting head  25  so that the user can press the actuating rod  30  to move outward to operate the actuating rod  30  to selectively move the steel ball  32  to force on the fitting head  25  (not shown) relatively to the embedding and fitting sleeve. 
     The engaging block  40  is a semilunar arc body. An internally curved surface of the engaging block  40  is formed with pawls  41  corresponding to the pawls  21  of the driving body  20  so that the position restricting effect between the engaging block  40  and the driving body  20  may be achieved. Furthermore, the middle of the rear edge of the engaging block  40  is formed with a clamping slot  45 . Two sidewall surfaces of the clamping slot  45  may be slopped conical surfaces  46  expanding outwards, as shown in  FIG. 3A , or flat straight surfaces  47 , as shown in  FIG. 3B , so that the control member  50  can be embedded and engaged with the engaging block  40 . 
     The control member  50  is composed of a base  51  and an actuating block  55 . The base  51  may be disposed in the second accommodating slot  14  of the head  11  of the handle  10 , and has an inserting slot  52 , in which the actuating block  55  may be inserted and swung. Also, an upper section of a wall surface of the inserting slot  52  of the base  51  is formed with a shaft hole  520 , on which the actuating block  55  is pivotally mounted. Furthermore, positioning slots  521  for positioning the actuating block  55 , which has been pressed leftward or rightward, are formed on the wall surface of the inserting slot  52  and below the shaft hole  520 . In addition, a cross slot  53 , across which the actuating block  55  may be placed, is formed on the base  51 , and the periphery of the base  51  is formed with an arced surface  54 . The rear edge of the engaging block  40  may rest against the arced surface  54 . The lower half section of the arced surface  54  of the base  51  is formed with a communicating hole  541  communicating with the inserting slot  52 . The lower half section of the actuating block  55  may be placed across the cross slot  53  of the base  51 . The upper half section of the actuating block  55  projects out of the long slot opening  16  of the head  11  so that the upper half section of the actuating block  55  can be pressed leftward or rightward by the user. Furthermore, the actuating block  55  has a projecting extension  56  inserting through the inserting slot  52  of the base  51 . Also, a shaft hole  550  corresponding to the shaft hole  520  of the inserting slot  52  is formed on the actuating block  55  such that the actuating block  55  may be pivotally connected to the base  51  through a shaft rod  57 . The actuating block  55  is formed with an accommodating hole  551  corresponding to the positioning slot  521  of the base  51 . An elastic member  581  and a positioning steel ball  582  are disposed in the accommodating hole  551 . Thus, the actuating block  55  may be restricted relatively to the positioning slot  521  of the base  51  using the positioning steel ball  582  that may be elastically moved. Furthermore, the end portion of the projecting extension  56  of the actuating block  55  is formed with a hole  552 . An actuating sheet  59  is embedded into the hole  552 . The actuating sheet  59  penetrating through the communicating hole  541  of the base  51  is clamped in the clamping slot  45  of the engaging block  40  so that the actuating block  55  can move the engaging block  40  to restrict the rotation direction of the driving body  20 . Thus, a push-type ratchet wrench which may be precisely positioned and conveniently switched and operated may be constructed. 
     According to the structural design of the invention, the invention may be applied to the actual condition. As shown in  FIGS. 2 ,  4  and  5 A, when the driving body  20  of the ratchet wrench has to be operated to achieve the operations of clamping in the clockwise direction (direction A) and rotating in the counterclockwise direction (direction B), the left side of the actuating block  55  of the control member  50  is pressed down so that the projecting extension  56  of the actuating block  55  is swung toward the other side, as shown in the operations of  FIGS. 5A to 5C . Thus, the actuating sheet  59  of the actuating block  55  can move the engaging block  40  to the same side so that the engaging block  40  can press the driving body  20  and the bolt or sleeve may be driven reversely. Oppositely, the ratchet wrench may be returned by way of free running in the forward direction so that the ratchet wrench can drive the bolt or sleeve reversely in the next cycle. 
     As shown in  FIGS. 2 ,  4  and  6 A, when the driving body  20  of the ratchet wrench has to be operated to achieve the operations of clamping in the counterclockwise direction (direction B) and rotating in the clockwise direction (direction A), the right side of the actuating block  55  of the control member  50  is pressed down so that the projecting extension  56  of the actuating block  55  is swung toward the other side, as shown in the operations of  FIGS. 6A to 6C . Thus, the actuating sheet  59  of the actuating block  55  can move the engaging block  40  to the same side so that the engaging block  40  can press the driving body  20  and the bolt or sleeve may be driven forward. Oppositely, the ratchet wrench may be returned by way of free running in the reverse direction so that the ratchet wrench can drive the bolt or sleeve forward in the next cycle. 
     The structure of the invention includes the following improvements. 
     First, the highly precise movement is obtained. When the ratchet wrench of the invention is actually used, the actuating block  55  of the control member  50  is pressed downward to achieve the object of changing the position of the engaging block  40 . Thus, the clamping direction and the free-running direction of the driving body  20  can be further controlled. Because the operation direction of the control member  50  is perpendicular to the moving direction of the engaging block  40 , the positioning effect is extremely good during the operation process, and the problem of the malfunction of the engaging block  40  during the operation process cannot occur. Thus, the operation precision of the ratchet wrench is greatly enhanced. 
     Second, the lifetime is lengthened. Because the operating direction of the control member  50  is vertical, the accommodating chamber is larger, so the assembly can be enlarged to reduce the breaking phenomenon caused by the improperly applied force during the operation process and thus to effectively lengthen its lifetime. 
     Third, the switching operation may be easily achieved. Because the size of the actuating block  55  is large and the positioning effect is extremely precise, the operation area of the user is large, and the operation convenience can be greatly enhanced. 
     Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.