Patent Publication Number: US-8109180-B2

Title: Dustproof ring for ratchet wrench

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a dustproof ring and, more particularly, to a dustproof ring for preventing dust from entering a head of a ratchet wrench. 
     A type of ratchet wrench includes a head and a handle interconnected to the head. The head includes a first, open side and a second side having an end wall with a hole rotatably receiving a stub formed on an end face of a drive member received in a compartment defined between the first and second sides of the head. A cover plate is mounted to the first side of the head to enclose the compartment. A drive column extends beyond the cover plate for driving a socket or the like. A pawl is received in a pawl groove defined in a periphery defining the compartment. A switch is received in a switch groove in the head and engages with the pawl, so that the driving direction f the ratchet wrench can be changed by rotational movement of the switch between two positions. To prevent dust from entering the compartment of the head via the hole, an O-ring is mounted in an annular groove formed in an inner face of the end wall and in direct communication with the hole. A C-clip is mounted and imparts a force to an outer side of the cover plate, so that the end face of the drive member tightly compress the O-ring with upper and lower edges of the O-ring tightly sandwiched between the end face of the drive member and a bottom wall of the annular groove. An example of such a ratchet wrench is disclosed in U.S. Pat. No. 7,311,019. However, significant force is required to overcome the friction between the end face of the drive member and the lower edge of the O-ring and between the bottom wall of the annular groove and the upper edge of the O-ring, risking injury to the hand of a user. 
     Thus, a need exists for a novel dustproof ring capable of preventing dust from entering the ratchet wrench while allowing easy, smooth operation of the ratchet wrench. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention solves this need and other problems in the field of sealing of ratchet wrenches, by providing, in a preferred form, a ratchet wrench including a body having a head and a handle interconnected to the head. The head includes first and second sides spaced along a rotating axis. The head further includes a compartment extending from the first side through the second side. A pawl groove is defined in an inner periphery of the compartment. The second side of the head includes an end wall defining a hole in communication with the compartment. The end wall includes an inner face facing the compartment. A drive member rotatably received in the compartment about the rotating axis. The drive member includes first and second ends spaced along the rotating axis. The second end of the drive member includes an end face. A gap is formed between the end face and the inner face along the rotating axis. One of the end face and the inner face defines a first abutment face. The other of the end face and the inner face includes an annular groove having a bottom wall defining a second abutment face. A spacing is defined between the first and second abutment faces along the rotating axis. The first end of the drive member is adapted to drive an object. The drive member further includes an outer periphery extending between the first and second ends. A plurality of teeth is formed in the outer periphery of the drive member. A pawl is slideably received in the pawl groove and includes a side having a plurality of teeth engaged with the plurality of teeth of the drive member. A dustproof ring is mounted and compressed in the annular groove. The dust ring presses against the first and second abutment faces. The dustproof ring in an uncompressed state has a natural maximum height along the rotating axis larger than the spacing. The dustproof ring includes first, second, and third sealing units. The third sealing unit is radially outwards of the first sealing unit in a radial direction perpendicular to the rotating axis. The second sealing unit is interconnected to and intermediate the first and third sealing units in the radial direction. The first sealing unit includes a first thickness along a first axis parallel to and spaced from the rotating axis. The second sealing unit includes a second thickness along a second axis parallel to and spaced from the rotating axis and the first axis. The third sealing unit includes a third thickness along a third axis parallel to and spaced from the rotating axis and the first and second axes. The second axis is intermediate the first and third axes in the radial direction. Each of the first, second, and third thicknesses is smaller than the spacing. A buffering space is formed between the first and third sealing units. The buffering space receives deformed portions of the dustproof ring received in the annular groove. 
     In preferred forms, the first and third sealing units press against one of the first and second abutment faces, and the second sealing unit presses against the other of the first and second abutment faces. The buffering space includes a first buffering space section formed between the first sealing unit and one of the first and second abutment faces, a second buffering space section formed between the second sealing unit and the other of the first and second abutment faces, and a third buffering space section formed between the third sealing unit and the one of the first and second abutment faces. The dustproof ring received in the annular groove is compressed along the rotating axis and deformed along the rotating axis and in the radial direction. The first, second, and third buffering space sections are isolated from each other. 
     The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The illustrative embodiments may best be described by reference to the accompanying drawings where: 
         FIG. 1  shows a partial, perspective view of a ratchet wrench of a first embodiment according to the preferred teachings of the present invention. 
         FIG. 2  shows an exploded, perspective view of the ratchet wrench of  FIG. 1 . 
         FIG. 3  shows a partial, cross sectional view of the ratchet wrench of  FIG. 1 . 
         FIG. 4  shows an enlarged view of a circled portion of  FIG. 3 . 
         FIG. 5  shows a partial, perspective view of a dustproof ring of  FIG. 4  with portions of the dustproof ring broken away and with the dustproof ring in a natural, uncompressed state. 
         FIG. 6  shows an enlarged view of a circled portion of  FIG. 5 . 
         FIG. 7  shows a partial, cross sectional view similar to  FIG. 4 , illustrating a dustproof ring of a second example according to the preferred teachings of the present invention. 
         FIG. 8  shows an enlarged view of the dustproof ring of  FIG. 7  with the dustproof ring in a natural, uncompressed state. 
         FIG. 9  shows a partial, cross sectional view similar to  FIG. 4 , illustrating a dustproof ring of a third example according to the preferred teachings of the present invention. 
         FIG. 10  shows an enlarged view of the dustproof ring of  FIG. 9  with the dustproof ring in a natural, uncompressed state. 
         FIG. 11  shows a partial, cross sectional view similar to  FIG. 4 , illustrating a dustproof ring of a fourth example according to the preferred teachings of the present invention. 
         FIG. 12  shows an enlarged view of the dustproof ring of  FIG. 11  with the dustproof ring in a natural, uncompressed state. 
         FIG. 13  shows a partial, cross sectional view of a ratchet wrench of a second embodiment according to the preferred teachings of the present invention. 
         FIG. 14  shows an enlarged view of a circled portion of  FIG. 13 . 
     
    
    
     All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiments will be explained or will be within the skill of the art after the following teachings of the present invention have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings of the present invention have been read and understood. 
     Where used in the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms “first”, “second”, “third”, “inner”, “outer”, “side”, “end”, “portion”, “section”, “axial”, “radial”, “annular”, “outward”, “spacing”, “clockwise”, “counterclockwise”, “height”, and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the invention. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A ratchet wrench according to the preferred teachings of the present invention is shown in the drawings and generally designated  100 . In preferred forms shown in  FIGS. 1-14 , ratchet wrench  100  includes a body  10  having a head  12  and a handle  11  interconnected to head  12 . Head  12  includes first and second sides  121  and  122  spaced along a rotating axis L. Head  12  further includes a compartment  13  extending from first side  121  through second side  122 . A pawl groove  15  is defined in an inner periphery of compartment  13 . Second side  122  of head  12  includes an end wall  132  defining a hole  134  in communication with compartment  13 . End wall  132  includes an inner face  133  facing the compartment  13  and an outer face  135  spaced from inner face  133  along rotating axis L. A switch groove  14  is defined in second side  122  of head  12  and in communication with pawl groove  15 . Pawl groove  15  is intermediate compartment  13  and switch groove  14  in a radial direction perpendicular to rotating axis L. The inner periphery of compartment  13  further includes an annular retaining groove  131  adjacent first side  121  of head  12 . 
     In the preferred forms shown in  FIGS. 1-14 , a drive member  20  is rotatably received in compartment  13  about rotating axis L. Drive member  20  includes first and second ends  21  and  22  spaced along rotating axis L. A drive portion  211  is formed on first end  21  of drive member  20  for driving an object such as a sleeve, a fastener, or the like. Drive portion  211  shown in  FIGS. 1-14  is a drive column extending beyond first side  121  of head  12  for driving a socket or the like. Second end  22  of drive member  20  includes an end face  221  and a stub  26  extending from end face  221  and rotatably received in hole  134  about rotating axis L. A gap G is formed between end face  221  and inner face  133  along rotating axis L. Drive member  20  further includes an outer periphery  202  extending between first and second ends  21  and  22 . A plurality of teeth  23  is formed in outer periphery  202  of drive member  20 . An annular groove  201  is formed in outer periphery  202  at first end  21 . A retaining member  24  is received in annular groove  201  of drive member  20  and retaining groove  131  of head  12 , allowing relative rotational movement between head  12  and drive member  20 . It can be appreciated that drive member  20  can have other forms according to the teachings of the present invention. As an example, drive member  20  does not have to include stub  26  and drive column  211 . Furthermore, drive member  20  can include a through hole extending from first end  21  through second end  22  and having an inner periphery for driving a fastener such as a nut, bolt head, or the like. 
     In the preferred forms shown in  FIGS. 1-14 , one of end face  221  and inner face  133  defines a first abutment face, and the other of end face  221  and inner face  133  includes an annular groove  16 ,  25  having a bottom wall  163 ,  253  defining a second abutment face. The first and second abutment faces are perpendicular to rotating axis L. A spacing T is defined between the first and second abutment faces along rotating axis L. Annular groove  16 ,  25  is spaced from hole  134  of end wall  132  in the radial direction. Furthermore, annular groove  16 ,  25  includes an outer peripheral face  162 ,  252  and an inner peripheral face  161 ,  251  intermediate outer peripheral face  162 ,  252  and rotating axis L in the radial direction. Bottom wall  163 ,  253  extends between inner and outer peripheral faces  161  and  162 ,  251  and  252 . In the preferred form shown in  FIGS. 1-12 , annular groove  25  is formed in end face  221  of drive member  20 , bottom wall  253  of annular groove  25  defines the second abutment face, and inner face  133  of end wall  13  defines the first abutment face. In the preferred form shown in  FIGS. 13-14 , annular groove  16  is formed in inner face  133  of end wall  13 , bottom wall  163  of annular groove  16  defines the second abutment face, and end face  221  of drive member  20  defines the first abutment face. 
     In the preferred forms shown in  FIGS. 1-14 , a pawl  30  is slideably received in pawl groove  15  and includes a first side  33  having a plurality of teeth  31  releasably engaged with teeth  23  of drive member  20 . Pawl  30  further includes a second side  34  having a pressing portion  32  facing switch groove  14 . 
     In the preferred forms shown in  FIGS. 1-14 , a control device  40  is mounted in switch groove  14  for controlling a driving direction of ratchet wrench  100 . Specifically, control device  40  includes a switch  41  rotatably received in switch groove  14 , a spring  42  received in a receptacle in switch  41 , and a pressing member  43  biased by spring  42  to press against pressing portion  32 . An end of pressing member  43  is received in the receptacle of switch  41  and includes a receptacle  431  receiving spring  42 . Teeth  31  of pawl  30  are biased by spring  42  to engage with teeth  23  of drive member  20 . Switch  41  is rotatable between two positions, so that the other end of pressing member  43  selectively presses against two ends of pressing portion  32 . Specifically, when pressing member  43  presses one of the ends of pressing portion  32 , head  12  and drive member  20  can rotate jointly in, e.g., a clockwise direction for driving the object, and head  12  can rotate freely in a counterclockwise direction relative to drive member  20  without driving the object. On the other hand, when pressing member  43  presses the other end of pressing portion  32 , head  12  and drive member  20  can rotate jointly in the counterclockwise direction for driving the object, and head  12  can rotate freely in the clockwise direction relative to drive member  20  without driving the object. Thus, the driving direction of ratchet wrench  100  can be changed by operating switch  14 . Other forms of control device  40  for changing the driving direction of drive member  20  would be within the skill of the art. 
     In the preferred forms shown in  FIGS. 1-14 , a dustproof ring  50 ,  50 B,  50 C,  50 D is mounted in annular groove  16 ,  25  and compressed. Furthermore, dustproof ring  50 ,  50 B,  50 C,  50 D presses against the first and second abutment faces. Dustproof ring  50 ,  50 B,  50 C,  50 D in the uncompressed state has a natural maximum height HSO along rotating axis L larger than spacing T. Dustproof ring  50 ,  50 B,  50 C,  50 D includes first, second, and third sealing units  51 ,  52 , and  53 . Third sealing unit  53  is radially outwards of first sealing unit  51  in the radial direction. Second sealing unit  52  is interconnected to and intermediate first and third sealing units  51  and  53  in the radial direction. First sealing unit  51  includes a first thickness T 51  along a first axis  511  parallel to and spaced from rotating axis L. Second sealing unit  52  includes a second thickness T 52  along a second axis  521  parallel to and spaced from rotating axis L and first axis  511 . Third sealing unit  53  includes a third thickness T 53  along a third axis  531  parallel to and spaced from rotating axis L and first and second axes  511  and  521 . Second axis  52  is intermediate first and third axes  51  and  53  in the radial direction. Each of first, second, and third thicknesses T 51 , T 52 , and T 53  is smaller than spacing T. Dustproof ring  50 ,  50 B,  50 C,  50 D includes an inner periphery  501  and an outer periphery  502  radially outwards of inner periphery  501  in the radial direction. First sealing unit  51  includes inner periphery  501 , and third sealing unit  53  includes outer periphery  502 . Second axis  521  is intermediate inner and outer peripheries  501  and  502  in the radial direction. First axis  511  is intermediate inner periphery  501  and second axis  521  in the radial direction. Third axis  531  is intermediate second axis  521  and outer periphery  502  in the radial direction. A buffering space is formed between first and third sealing units  51  and  53 . The buffering space receives deformed portions of dustproof ring  50 ,  50 B,  50 C,  50 D received in annular groove  16 ,  25 . 
     In the preferred forms shown in  FIGS. 1-14 , first and third sealing units  51  and  53  press against one of the first and second abutment faces, and second sealing unit  52  presses against the other of the first and second abutment faces. In the preferred form shown in  FIGS. 1-6 , first and third sealing units  51  and  53  press against bottom wall  253  of annular groove  25 , and second sealing unit  52  presses against inner face  133  of end wall  132 . In the preferred forms shown in  FIGS. 7-14 , first and third sealing units  51  and  53  press against inner face  133  of end wall  132 , and second sealing unit  52  presses against bottom wall  253  of annular groove  25 . 
     In the preferred forms shown in  FIGS. 1-14 , the buffering space includes a first buffering space section  512  formed between first sealing unit  51  and one of the first and second abutment faces, a second buffering space section  522  formed between second sealing unit  52  and the other of the first and second abutment faces, and a third buffering space section  532  formed between third sealing unit  53  and the one of the first and second abutment faces. 
     In the preferred form shown in  FIGS. 1-6 , second sealing unit  52  of dustproof ring  50  has substantially triangular cross sections, and each of first and third buffering space sections  512  and  532  of dustproof ring  50  has substantially trapezoidal cross sections. Second buffering space section  522  has substantially trapezoidal cross sections. In the preferred form shown in  FIGS. 7 and 8 , dustproof ring  50 B in the uncompressed state is asymmetric in cross section. First sealing unit  51  of dustproof ring  50 B has substantially triangular cross sections, and third sealing unit  53  of dustproof ring  50 B has substantially rectangular cross sections. In the preferred form shown in  FIGS. 9 and 10 , second sealing unit  52  of dustproof ring  50 C includes two end portions spaced in the radial direction and having substantially rectangular cross sections. First and third sealing units  51  and  53  of dustproof ring  50 C respectively extend from the end portions of second sealing unit  52 . Second buffering space section  522  of dustproof ring  50 C has substantially trapezoidal cross sections. In the preferred form shown in  FIGS. 11 and 12 , dustproof ring  50 D has arc-shaped cross sections. 
     As mentioned above, dustproof ring  50 ,  50 B,  50 C,  50 D in the uncompressed state has a natural maximum height HSO along rotating axis L larger than spacing T. In the preferred form shown in  FIGS. 1-6 , first and third buffering space sections  512  and  532  allow movement of first and third sealing unit  51  and  53  toward end face  133 , and second buffering space section  522  allows movement of second sealing unit  52  toward bottom wall  253  of annular groove  25 . In the preferred forms shown in  FIGS. 7-12 , first and third buffering space sections  512  and  532  allow movement of first and third sealing unit  51  and  53  toward bottom wall  253  of annular groove  25 , and second buffering space section  522  allows movement of second sealing unit  52  toward end face  133 . In the preferred form shown in  FIGS. 13-14 , first and third buffering space sections  512  and  532  allow movement of first and third sealing unit  51  and  53  toward end face  221  of drive member  20 , and second buffering space section  522  allows movement of second sealing unit  52  toward bottom wall  163  of annular groove  16 . Thus, dustproof ring  50 ,  50 B,  50 C,  50 D received in annular groove  16 ,  25  is compressed along rotating axis L and deformed along rotating axis L and in the radial direction with first, second, and third buffering space sections  512 ,  522 , and  532  receiving the deformed portions of dustproof ring  50 ,  50 B,  50 C,  50 D. In the preferred forms shown in  FIGS. 1-14 , first, second, and third buffering space sections  512 ,  522 , and  532  are isolated from each other. Gap G between the first and second abutment faces is, thus, sealed to prevent dust from entering compartment  13  of head  12  via hole  134 . Furthermore, each of first, second, and third buffering sealing units  51 ,  52 , and  53  is compressed by only one of the first and second abutment faces, so that the friction to each of first, second, and third sealing units  51 ,  52 , and  53  is small, allowing smooth rotation of drive member  20  relative to head  12 . 
     Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.