Abstract:
A wrench comprises a handle and a head extended from the handle. A web is defined between the handle and the head. The head includes a compartment in which a drive member is rotatably received. The web includes a transverse through-hole having an intermediate portion communicated with the compartment. A cavity is defined in the web and communicated with the transverse through-hole. A switch member is mounted in the cavity and rotatable relative to the handle between two positions corresponding to two opposite ratcheting directions of the handle. A pawl is slidably mounted in the transverse through-hole for engaging with the drive member. The pawl remains in the transverse through-hole during operation.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an easy-to-manufacture and easy-to-assemble ratcheting-type wrench. 
     2. Description of the Related Art 
     Several factors are considered in designing wrenches and spanners, including improving the torque-bearing capacity, providing as many teeth as possible for the drive member, and providing an easy-to-manufacture structure. FIG. 20 of the drawings illustrates a conventional wrench of the type having a handle B′ and a head in which a drive member A′ is rotatably received. A pawl D′ is slidably received in a transverse through-hole C′ in a web between the handle B′ and the head. However, an end of the pawl D′ extends beyond the transverse through-hole C′ and thus adversely affects operation of the wrench when used in a limited space. A two-pawl type wrench was proposcd to solve this problem. As illustrated in FIGS. 21 through 23, the two-pawl type wrench includes a handle  1 ′ and a head  11 ′ extended from the handle  1 ′. A drive member  2 ′ is rotatably received in the head  11 ′, a receptacle  12 ′ is defined in a web between the handle  1 ′ and the head  11 ′, and a spring-biased switch member  4 ′ is mounted in a cavity  13 ′ in the web. Two spaced pawls  3 ′ are received in the receptacle  12 ′ and are biased by two springs  6 ′, respectively. A threaded end cap  5 ′ is engaged with a threaded outer end  121 ′ of the receptacle  12 ′ to enclose the pawls  3 ′ and springs  6 ′. As illustrated in FIGS. 22 and 23, the switch member  4 ′ is turned to bias one of the pawls  3 ′ to engage teeth  31 ′ thereof with the drive member  2 ′ to thereby change the ratcheting direction of the wrench. However, it was found that the switch member  4 ′ cannot be reliably retained in place and thus tends to disengage from the cavity  13 ′. In addition, the pawl  3 ′ engaged with the drive member  2 ′ is not engaged with an inner longitudinal wall that defines the transverse through-hole and that faces the drive member  2 ′. As a result, the torque-bearing capacity of the wrench is poor. Furthermore, the outer pawl  3 ′ (FIGS. 22 and 23) tends to get stuck when the threaded end cap  5 ′ is mounted too close to the switch member  4 ′. On the other hand, if the threaded end cap  5 ′ is too far away from the switch member  4 ′, the pawl  3 ′ cannot be firmly engaged with the drive member  2 ′. Further, the threaded end cap  5 ′ tends to be disengaged from the web between the handle  1 ′ and the head  11 ′, as the former is in threading engagement with the threaded outer end  121 ′ of the receptacle  12 ′. 
     FIGS. 24 through 26 illustrate another conventional wrench having a substantially V-shape transverse through-hole  25 ′ in a web between a handle  20 ′ and a head  21 ′ thereof. The head  21 ′ includes a compartment in which a drive member  22 ′ is rotatably received. A spring-biased pawl  23 ′ is received in each limb of the V-shape transverse through-hole  25 ′. A switch member  30 ′ includes a stem  35 ′ pivotally received in a cavity  24 ′ in the web and a thumb-piece  32 ′ extending from the stem  35 ′ for manual operation, thereby switching the switch member  30 ′ between two positions corresponding to two opposite ratcheting directions of the wrench. The thumb piece  32 ′ of the switch member  30 ′ includes a downwardly facing receptacle  36 ′ (FIG. 26) for receiving a spring  37 ′ and a ball  38 ′ that is biased by the spring  37 ′ to be positioned in one of two positioning recesses  281 ′ (FIG. 25) in a sector-like recessed area  28 ′ (FIG. 24) of the web. The switch member  30 ′ may be retained in place reliably. However, a C-clip  33 ′ is required for mounting the switch member  30 ′ in place. In addition, processing of the sector-like recessed area  28 ′ in the web and the V-shape transverse through-hole  25 ′ is difficult. Mounting of the switch member  30 ′ as well as the pawl  23 ′ and associated springs  26 ′ and threaded end caps  27 ′ are troublesome and time-consuming. The sector-like recessed area  28 ′ in the web results in an increase in the overall thickness of the wrench, which limits application of the wrench in limited spaces. 
     U.S. Pat. No. 6,282,991 discloses a biasing arrangement for a pawl of a reversible ratchet-type wrench. However, the pawl protrudes beyond the handle during change in the ratcheting direction and thus adversely affects operation of the wrench in a limited space, as the protruded portion of the pawl tends to impinge on an object in the limited space. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an easy-to-manufacture and easy-to-assemble ratcheting-type wrench. 
     In accordance with a first aspect of the invention, a wrench comprises: 
     a handle comprising a first lateral side and a second lateral side opposite to the first lateral side; 
     a head extended from the handle, a web being defined between the handle and the head, the head including a compartment, the web including a transverse through-hole having an intermediate portion communicated with the compartment, the transverse through-hole extending from the first lateral side to the second lateral side of the handle, a cavity being defined in the web and communicated with the transverse through-hole; 
     a drive member rotatably mounted in the compartment of the head and including a plurality of teeth on an outer periphery thereof; 
     a switch member mounted in the cavity and rotatable relative to the handle between two positions corresponding to two opposite ratcheting directions of the handle; and 
     a pawl mounted in the transverse through-hole and slidable along a lengthwise direction of the transverse through-hole, the pawl including a side facing the compartment, the side of the pawl including a first toothed portion and a second toothed portion that are selectively engaged with the teeth of the drive member according to one of the positions of the switch member relative to the handle. 
     In accordance with a second aspect of the invention, a wrench comprises: 
     a handle; 
     a head extended from the handle, a web being defined between the handle and the head, the head including a first compartment, the web including a second compartment communicated with the first compartment, a cavity being defined in the web and communicated with the second compartment; 
     a drive member rotatably mounted in the first compartment of the head and including a plurality of teeth on an outer periphery thereof; 
     a switch member mounted in the cavity and rotatable relative to the handle between two positions corresponding to two opposite ratcheting directions of the handle; and 
     a pawl slidably mounted in the second compartment, the pawl including a first side facing the first compartment and a second side facing away from the first compartment, the first side of the pawl including a first toothed portion and a second toothed portion that are selectively engaged with the teeth of the drive member according to one of the positions of the switch member relative to the handle, the second side of the pawl including a notch, the switch member having a portion extending into the notch of the pawl, thereby preventing disengagement of the switch member from the cavity. 
     The wrench in accordance with the present invention has a simple structure and is easy to assemble by using a C-clip without the need of any screws. In addition, the compartment, the transverse hole and the cavity can be processed by means of milling. No computer lathe is required. Thus, the cost is low, the manufacture process is short, and the production time is also short. Furthermore, the pawl will not protrude beyond the transverse through-hole. Inadvertent switching of the ratcheting direction is avoided. Further, the drive member is firmly engaged with and in intimate contact with the associated toothed portion of the pawl during ratcheting. The risk of slippage or so-called “teeth jump” is avoided. The second side of the pawl contacts with the inner longitudinal wall of the transverse through-hole by a larger area such that the wrench in accordance with the present invention may bear a higher torque. This also prevents inadvertent relative displacement between the biasing member and the pawl. The biasing member in the form of a coil spring provides smooth switching of the switch member, while the rigid pin provides an alternative option for the user. Further, a bridge is provided between the compartment and the cavity, which increases the strength of the wrench, thereby providing a higher torque-bearing capacity. Further, in accordance with the second aspect of the invention, the lower portion of the column extends into the notch of the pawl. Disengagement of the switch member from the cavity is prevented without using any additional elements. 
     Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a portion of a wrench in accordance with the present invention. 
     FIG. 2 is an exploded perspective view of the portion of the wrench in FIG.  1 . 
     FIG. 3 is a sectional view of the portion of the wrench in FIG.  1 . 
     FIG. 4 is a sectional view taken along line  4 — 4  in FIG.  3 . 
     FIG. 5 is a sectional view taken along line  5 — 5  in FIG.  3 . 
     FIG. 6 is a view similar to FIG. 5, wherein the switch member is in a position for ratcheting in a reverse direction. 
     FIG. 7 is a view similar to FIG. 4, wherein the switch member is in a position for ratcheting in a reverse direction. 
     FIG. 8 is a perspective view of a portion of a modified embodiment of the wrench in accordance with the present invention. 
     FIG. 9 is an exploded perspective view of the portion of the wrench in FIG.  8 . 
     FIG. 10 is an exploded perspective view of a portion of another modified embodiment of the wrench in accordance with the present invention. 
     FIG. 11 is a sectional view of the portion of the wrench in FIG.  10 . 
     FIG. 12 is a sectional view taken along line  12 — 12  in FIG. 11 
     FIG. 13 is a sectional view similar to FIG. 12, wherein the switch member is in a position for ratcheting in a reverse direction. 
     FIG. 14 is a sectional view taken along line  14 — 14  in FIG.  11 . 
     FIG. 15 is a sectional view similar to FIG. 14, wherein the switch member is in a position for ratcheting in a reverse direction. 
     FIG. 16 is an exploded perspective view of a portion of a further modified embodiment of the wrench in accordance with the present invention. 
     FIG. 17 is a sectional view of the portion of the wrench in FIG.  16 . 
     FIG. 18 is a sectional view taken along line  18 — 18  in FIG.  17 . 
     FIG. 19 is a sectional view similar to FIG. 18, wherein the switch member is in a position for ratcheting in a reverse direction. 
     FIG. 20 is a top view, partly sectioned, of a portion of a conventional wrench. 
     FIG. 21 is an exploded view of a portion of another conventional wrench. 
     FIG. 22 is a top view, partly sectioned, of the portion of the conventional wrench in FIG.  21 . 
     FIG. 23 is a view similar to FIG. 22, wherein the switch member of the wrench is in a position for ratcheting in a reverse direction. 
     FIG. 24 is an exploded perspective view of a further conventional wrench. 
     FIG. 25 is a top view, partly sectioned, of a portion of the conventional wrench in FIG.  24 . 
     FIG. 26 is a side view, partly sectioned, of the portion of the conventional wrench in FIG.  24 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 through 4, a wrench  10  in accordance with the present invention generally includes a handle  12  and a head  11  extended from the handle  12 , a web  18  being defined between the handle  12  and the head  11 . The head  11  includes a compartment  13 . A rectangular transverse through-hole  14  (FIG. 4) is defined in the web  18  and includes an intermediate portion communicated with the compartment  13 . The transverse through-hole  14  extends from one lateral side  19   a  of the handle  12  to the other lateral side  19   b  of the handle  12 , thereby defining an opening  141  in each of two ends thereof. The transverse through-hole  14  includes an inner longitudinal wall  142  that faces the compartment  13 , which will be described later. The web  18  further includes a cavity  15  defined therein and communicated with the transverse through-hole  14 . Referring to FIGS. 2 and 3, the cavity  15  includes a vertical portion  15   a  that extends upward to an upper side of the handle  12 . Thus, a bridge  16  is formed on the upper side of the handle  12  and between the compartment  13  and the cavity  15 . The vertical portion  15   a  of the cavity  15  includes a first positioning recess  151  and a second positioning recess  152 . The first and second positioning recesses  151  and  152  can be processed by means of a conventional drilling or milling machine, which is very easy to manufacture. 
     A drive member  20  (in the form of a drive gear in this embodiment) is rotatably mounted in the compartment  13 . The drive member  20  includes a plurality of teeth  21  on an outer periphery thereof and an annular groove  22  in a lower portion of the outer periphery thereof. A portion of the teeth  21  of the drive member  20  extends into the transverse through-hole  14 , best shown in FIG.  4 . The drive member  20  further includes a polygonal inner periphery  23  for engaging with a fastener, such as a nut or a bolt head. A C-clip  30  is engaged in the annular groove  22  of the drive member  20  and an annular groove  131  (FIG. 2) defined in a lower portion of an inner periphery defining the compartment  13 , thereby rotatably mounting the drive member  20  in the compartment  13 , best shown in FIG.  3 . 
     A substantially rectangular pawl  40  is mounted in the transverse through-hole  14  and slidable along a lengthwise direction of the transverse through-hole  14 . The pawl  40  includes a first lateral side  47  facing the drive member  20  and a second lateral side  46  facing away from the drive member  20 . As illustrated in FIG. 4, the first lateral side  47  of the pawl  40  is preferably arcuate and includes a first toothed portion  41 , a second toothed portion  42 , and a recessed portion  43  between the first toothed portion  41  and the second toothed portion  42 . The pawl  40  further includes a transverse hole  44  in an intermediate portion thereof. In addition, a notch  45  is defined in a lower portion of the second lateral side  46 . 
     A switch member  50  is rotatably mounted in the vertical portion  15   a  of the cavity  15 . In this embodiment, the switch member  50  includes an enlarged head  52  larger than a diameter of the vertical portion  15   a  of the cavity  15 , a thumb piece  51  extended radially outward from the enlarged head  52  for easy manual operation by a user, and a column  53  extended downward from the enlarged head  52  and received in the vertical portion  15   a  of the cavity  15 . The column  53  includes a first receptacle consisting of a first portion  54  adjacent to the transverse through-hole  14  and a second portion  55  distal to the transverse through-hole  14 , the first portion  54  having a diameter greater than that of the second portion  55 , best shown in FIG.  4 . The column  53  further includes a second receptacle  56  extending at a level other than that of the first receptacle. 
     As illustrated in FIG. 5, a positioning means  60  is provided for retaining the switch member  50  in place. In this embodiment, the positioning means  60  includes a spring  61  mounted in the second receptacle  56  of the column  53  and a ball  62  partially received in the second receptacle  56  and partially received in one of the positioning recesses  151  and  152  of the vertical portion  15   a  of the cavity  15 . Referring to FIG. 4, a biasing member  70  (in the form of a coil spring) is mounted in the first receptacle of the column  53  and has a first end  71  extended into the transverse hole  44  of the pawl  40  and a second end  72  in the second portion  55  of the first receptacle. 
     In assembly, the ball  62  and the spring  61  are mounted into the second receptacle  56  of the switch member  50 , which is then mounted into the cavity  15 . The pawl  40  is inserted into the rectangular transverse through-hole  14  of the web  18  via an opening  141  of the transverse through-hole  14 . The first side  47  of the pawl  40  faces the compartment  13 . A lower portion of the column  53  extends into the notch  45  of the pawl  40  to prevent disengagement of the switch member  50  from the cavity  15 . Next, the second end  72  of the biasing member  70  is inserted into the second portion  55  of the switch member  50  with the first end  71  of the biasing member  70  retaining in the transverse hole  44  of the pawl  40 , best shown in FIGS. 3 and 4. Then, the C-clip  30  is mounted into the annular groove  22  of the drive member  20 , which is then mounted into the compartment  13  of the head  11 . The C-clip  30  expands outward into the annular groove  131  of the head  11 , thereby rotatably mounting the drive member  20  in the compartment  13 . It is noted that the assembly procedure can be accomplished easily and quickly without any screws or covers. In addition, referring to FIG. 3, the lower portion of the column  53  extends into the notch  45  of the pawl  40 . Disengagement of the switch member  50  from the cavity  15  is prevented without using any additional elements. 
     In use, referring to FIGS. 4 and 5, when the ball  62  is engaged with the second positioning recess  152  of the switch member  50 , the first end  71  of the biasing member  70  bears against a lower wall defining the transverse hole  44  of the pawl  40 . The biasing member  70  exerts a force to the pawl  40  that can be imparted into a horizontal force parallel to the lengthwise direction of the pawl  40  and a vertical force that is normal to the horizontal force. If the handle  12  is turned clockwise, the drive member  20  is firmly engaged with the second toothed portion  42  of the pawl  40  under the action of the vertical force, thereby tightening or loosening the fastener (not shown) engaged in the polygonal inner periphery  23  of the drive member  20 . A higher torque is provided, as the drive member  20  is firmly engaged with and in intimate contact with the second toothed portion  42  of the pawl  40 . In addition, the force transmitted to the pawl  40  from the drive member  20  is distributed to the inner longitudinal wall  142  of the transverse through-hole  14  having a relatively large area. As a result, the wrench in accordance with the present invention may bear higher torque. The drive member  20  rotates freely when the handle  12  is turned counterclockwise. 
     Referring to FIG. 6, the switch member  50  is pivoted through an angle to engage the ball  62  with the first positioning recess  151  of the switch member  50 . The first end  71  of the biasing member  70  bears against an upper wall defining the transverse hole  44  of the pawl  40 , as shown in FIG.  7 . The biasing member  70  exerts a force to the pawl  40  that can be imparted into a horizontal force parallel to the lengthwise direction of the pawl  40  and a vertical force that is normal to the horizontal force. If the handle  12  is turned counterclockwise, the drive member  20  is firmly engaged with the first toothed portion  41  of the pawl  40  under the action of the vertical force, thereby tightening or loosening the fastener engaged in the polygonal inner periphery  23  of the driver member  20 . Again, a higher torque is provided, as the drive member  20  is firmly engaged with and in intimate contact with the first toothed portion  41  of the pawl  40 . In addition, the force transmitted to the pawl  40  from the drive member  20  is distributed to the inner longitudinal wall  142  of the transverse through-hole  14  having a relatively large area. As a result, the wrench in accordance with the present invention may bear higher torque. The drive member  20  rotates freely when the handle  12  is turned clockwise. It is noted that the pawl  40  will not protrude beyond the transverse through-hole  14 . Inadvertent switching in the ratcheting direction is avoided. 
     In the first-mentioned embodiment, the first and second positioning recesses  151  and  152  can be processed by any conventional milling or drilling machine. The assembly procedure can be achieved easily and quickly by means of a C-clip  30 , no screw or cover is required. In addition, the switch member  50  can be retained in place without any other retaining device. 
     FIGS. 8 and 9 illustrate a modified embodiment of the wrench in accordance with the present invention, the difference between this embodiment and the first embodiment is that the transverse through-hole (now designated by  17 ) is cylindrical, and the pawl (now designated by  90 ) is substantially cylindrical. The pawl  90  includes a first side having a first toothed portion  91 , a second toothed portion  92 , and a recessed portion  93  between the first toothed portion  91  and the second toothed portion  92 . The pawl  90  further includes a second side  96  having a notch  95  defined in a lower end thereof. A transverse hole  94  is defined in an intermediate portion of the pawl  90  for receiving the first end  71  of the biasing member  70 . Other structure and operation of the wrench are identical to those of the first embodiment. 
     FIGS. 10 through 15 illustrate another embodiment modified from the first embodiment. The difference between this embodiment and the first embodiment is that the biasing member  70  in the first embodiment is replaced by a rigid pin  80  having a first end  81  and a second end  82 . Structure and operation of this embodiment are identical to those of the first embodiment, except that the pin  80  is more rigid than the biasing member  70  in the form of a coil spring. 
     FIGS. 16 through 19 illustrate a further embodiment modified from the first embodiment. The difference between this embodiment and the first embodiment is that the first and second positioning recesses  151  and  152  in the vertical portion  15   a  of the cavity  15  in the first embodiment are omitted. Instead, an inclined receptacle  154  is defined in the handle  12  and includes an open end facing the vertical portion  15   a  of the cavity  15 , best shown in FIG.  17 . In addition, the column  53  of the switch member  50  includes a first positioning notch  57  and a second positioning notch  58 , best shown in FIG.  18 . As illustrated in FIGS. 17 through 19, the ball  62  is biased by the spring  61  to engage with one of the positioning recesses  57  and  58 . Other structure and operation of the wrench are identical to those of the first embodiment. 
     According to the above description, it is appreciated that the wrenches in accordance with the present invention have simple structures and are easy to assemble by using a C-clip  30  without the need of any screws. In addition, the compartment  13 , the transverse through-hole  14 ,  17 , and the cavity  15  can be processed by means of milling. No computer lathe is required. Thus, the cost is low, the manufacture process is short, and the production time is also short. Furthermore, the first and second positioning recesses  151  and  152  in the first embodiment and the inclined receptacle  154  in the embodiment illustrated in FIGS. 16 through 19 can be processed by means of milling, which is easy to manufacture. Furthermore, the pawl  40 ,  90  will not protrude beyond the transverse through-hole  14 ,  17 . Inadvertent switching of the ratcheting direction is avoided. Further, the drive member  20  is firmly engaged with and in intimate contact with the associated toothed portion  41 ,  42 ,  91 ,  92  of the pawl  40 ,  90  during ratcheting. The risk of slippage or so-called “teeth jump” is avoided. The second side  46 ,  96  of the pawl  40 ,  90  contacts with the inner longitudinal wall  142  of the transverse through-hole  14 ,  17  by a larger area such that the wrench in accordance with the present invention may bear a higher torque. This also prevents inadvertent relative displacement between the biasing member  70  and the pawl  40 ,  90 . The biasing member  70  in the form of a coil spring provides smooth switching of the switch member  50 , while the rigid pin  80  provides an alternative option for the user. Further, a bridge  16  is provided between the compartment  13  and the cavity  15 , which increases the strength of the wrench, thereby providing a higher torque-bearing capacity. Further, the lower portion of the column  53  extends into the notch  45 ,  95  of the pawl  40 ,  90 . Disengagement of the switch member  50  from the cavity  15  is prevented without using any additional elements. 
     Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the invention as hereinafter claimed.