Patent Publication Number: US-2011061213-A1

Title: Hand puller with a structure of double stopping plates

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The invention relates to a hand puller and, in particular to a hand puller with an improved structure of double stopping plates. 
     2. Related Art 
       FIG. 11  shows a conventional hand puller. Its fixing part  80  and pulling part  81  are joined with an axle part  82 . The axle part  82  has a ratchet  83 . The fixing part  80  has a stopping plate  85 . The pulling part  81  has a driving claw  86 . The stopping plate  85  and the driving claw  86  engage with the ratchet  83 . 
     As shown in the structure, the puller has only one stopping plate  85 . The stopping plate  85  may not accurately engage with the ratchet  83  because there is some variation in the tooth span. When the puller is tightened, the stopping plate  85  may depart from the ratchet so that the strap falls off. 
       FIG. 12  shows another conventional hand puller. The fixing part  90  has two stopping plates  91  installed on the same side of the ratchet  92 . They engage with the ratchet  92  from top and bottom, respectively, to achieve strap tightening. 
     However, the stopping walls on both sides of the fixing part  90  have to be higher so that the two stopping plates  91  can be installed on the same side of the ratchet  92 . The structure of the fixing part  90  is thus larger than the fixing part with one stopping plate. This increases the cost of the hand puller. Besides, when the hand puller relaxes the strap, one sometimes has to do it slowly. During the slow strap release of the hand puller with two stopping plates  91 , the user has to pull the pulling part  93  so that the two stopping plates  91  back their teeth one by one. Without appropriate control, the strap may be released too much. 
     Therefore, it is an objective of the invention to solve the problems in the conventional hand puller. 
     SUMMARY OF THE INVENTION 
     An objective of the invention is to provide a hand puller with a structure of double stopping plates to achieve the effect of engaging and stopping its ratchet with the two stopping plates when the hand puller holds its strap. 
     Another objective of the invention is to provide a slow strap release mechanism at the fixing part so that the driving claw of the pulling part can shift in the stroke and the ratchet can back the strap out tooth by tooth. 
     To achieve the above objectives, the invention has an axle part between a fixing part and a pulling part. Both ends of the axle part have a ratchet. The fixing part has a stopping plate. The pulling part has a driving claw. The stopping plates and the driving claw engage with the teeth of the ratchets, respectively. 
     Moreover, the fixing part has a stopping plate on the opposite sides of the axle part. When the driving claw rotates the ratchet, the stopping plate on one side of the ratchet engages the bottom part of the teeth of the ratchet. The stopping plate on the opposite side of the ratchet urges against the top part of the teeth the ratchet. The two stopping plates thus move reciprocally between the top and bottom parts of the teeth. 
     At the pivotal axle part, the fixing part has a guiding section for the driving claw to urge while pulling. The guiding section has a stopping wall for the driving claw to urge at the end of the stroke. A positioning groove is formed above the stopping wall. A sliding groove is formed between the positioning groove and the guiding section. 
     The driving claw drives the ratchet to rate during the stoke of the guiding section and urges against the stopping wall when it is fully pulled. When the driving claw is pulled up to the positioning groove and disposed therein, it completely departs from the ratchet. Two protruding parts are disposed corresponding to the two stopping plates at the axle part of the pulling part. When the driving claw moves back and forth in the sliding groove, the two protruding parts push away the corresponding stopping plates. The teeth of the ratchet thus back out the strap tooth by tooth. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will become more fully understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein: 
         FIG. 1  is a three-dimensional view of the invention; 
         FIG. 2  is a three-dimensional exploded view of the invention; 
         FIG. 3  is a side view of the structure of the invention; 
         FIG. 4  is a schematic view of the pulling part being pulled up according to the invention; 
         FIG. 5  is a schematic view of the disclosed driving claw at the front end of the sliding groove; 
         FIG. 6  is a schematic view of the disclosed driving claw at the back end of the sliding groove; 
         FIG. 7  is a schematic view of the driving claw in the positioning groove; 
         FIG. 8  is a schematic view of the relative position of the disclosed two hand puller before they are combined; 
         FIG. 9  is a schematic view of the assembled two hand puller according to the invention; 
         FIG. 10  is a three-dimensional view of a second embodiment of the invention; 
         FIG. 11  is a schematic view of a conventional hand puller; and 
         FIG. 12  is a schematic view of another conventional hand puller. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements. 
     Please refer to  FIGS. 1 to 7  for an embodiment of the invention. It is used only for the illustration purpose. The invention is not restricted to such a structure. 
     This embodiment provides an improved hand puller. An axle part  3  goes through a fixing part I and a pulling part  2 . Both ends of the axle part  3  are provided with a ratchet  4 , respectively. The fixing part  1  has stopping plates I 1 . The pulling part  2  has a driving claw  21 . The stopping plate  11  and the driving claw  21  engage with the teeth  41  of the ratchet  4 . As shown in  FIG. 2 , the pulling part  2  can depart from the fixing part  1 . 
     The fixing part  1  has a stopping plate  11  ob opposite ends of the axle  3 , respectively. When the driving claw  21  drives the ratchet  4 , the stopping plate  11  on one side of the ratchet  4  engages with the bottom part  41 a of the teeth  41  of the ratchet  4 . The stopping plate  11  on the opposite side of the ratchet  4  urges against the top part  41   b  of the teeth  41  of the ratchet  4 . The two stopping plates  11  alternately perform a reciprocal motion between the bottom part  41   a  and the top part  41   b  of the teeth  41 . 
     As shown in  FIGS. 3 to 7 , the fixing part I has a guiding section  12  at the pivotal axle part  3  for the end of the driving claw  21  to urge against when it is pulled. The guiding section has a stopping wall  13  for the sidewall of the driving claw  21  to urge and stop at the end of its stroke. A positioning groove  14  is formed on the upper portion of the stopping wall  13 . A sliding groove  15  is formed between the positioning groove  14  and the guiding section  12 . 
     According to the above-mentioned stricture (also shown in  FIGS. 3 and 4 ), the driving claw  21  drives the ratchet  4  during the stroke of the guiding section  12 . It urges against the stopping wall  13  when fully pulled. The pulling part  2  is provided with two protruding parts  22  at the axle part  3  corresponding to the two stopping plates  1   1 . As shown in  FIGS. 5 and 6 , as the driving claw  21  moves back and forth in the sliding groove  15 , the two protruding parts  22  push away the corresponding stopping plates  11 , respectively. The teeth  41  of the ratchet  4  thus back out the strap tooth by tooth. As shown in  FIG. 7 , the driving claw  21  completely depart from the ratchet  41  when it is pulled and inserted into the positioning groove  14 . 
     As shown in  FIGS. 8 and 9 , the fixing part  1  in this embodiment has two sets of through holes  16  in the back. The two sets of through holes  16  are in communication when the fixing parts  1  of two hand pullers are connected. Two sets of locking elements  17  go through and connect them in this case. 
     From the above description, it is easy to see that one advantage of the invention is in that two opposite sides of the ratchet of the fixing part  1  have a stopping plate, respectively. When the pulling part  2  is pulled, even if the teeth  41  on the ratchet have some variation in their span, the cooperation of the two stopping plates  11  still enable them to engage with the ratchet  4 , preventing the strap from falling off. It is not necessary to increase the height of the structure on both sides of the fixing part to accommodate the tho stopping plates  11  as in the prior art. The component cost is thus lower. Moreover, to prevent cargo from shifting to one side and even toppling over because a single set of hand puller impose a tightening force only in one direction, the fixing part I of the invention can involve two sets of hand pullers connected via two sets of through holes  16 . Therefore, the user can use the same pulling part  2  to drive two fixing parts  1 , exerting a more uniform force. 
     Of course, the invention has many other embodiments that only vary in details. Please refer to  FIG. 10  for a second embodiment of the invention. The fixing part  1 A are fixed to the pulling part  2 A. That is, the fixing part  1 A and the pulling part  2 A cannot be separated. However, such a fixed-type hand puller still has the above-mentioned two stopping plates  11 A and achieves the slow strap backing effect. 
     Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to people skilled in the art. Therefore, it is contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.