Patent Publication Number: US-2016221163-A1

Title: Open end continuous rotation ratchet wrench

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to wrenches, and more particularly to an open end reversible ratchet wrench that is operable by squeezing a lever to rotate a moving jaw continuously about one or more complete 360° rotations relative to a central rotational axis of the mouth of the wrench in order to selectively advance or retreat a multi-sided nut element along a threaded element of a work piece, while maintaining the handle of the wrench stationary and without having to remove the wrench from the work piece. 
     2. Discussion of the Related Art 
     Open end wrenches are well known in the art and are typically defined by a head and elongate handle that is integral with the head. A jaw on the head of the wrench surrounds an open mouth that is usually positioned at a slight angle in relation to the handle. The open mouth is specifically sized for receiving a work piece for engagement with the inner surfaces of the jaw in a manner which allows rotation of the work piece upon applying torque using the handle. Most open end wrenches are structured for grasping and rotating a multi-sided element, such as a hex nut, in order to tightened or loosen the nut element on a threaded cylindrical element, such as a bolt shaft or other threaded member. 
     In the past, others have proposed various open end ratchet wrenches that typically include a rotating jaw. A ratchet is used to permit rotation in one direction while preventing rotation in the opposite direction. More particularly, the ratchet drives rotation of the jaw in a selected direction of rotation and blocks reverse rotation. In many instances, the ratchet cooperates with ratchet pawls that engage the ratchet. Examples of open end ratchet wrenches are disclosed in prior art patents, including the U.S. Patents to Stanton, U.S. Pat. No. 5,456,143; Sroka U.S. Pat. No. 5,388,479; Gamble U.S. Pat. No. 5,768,958; and Ashby, U.S. Pat. No. 5,467,672. These various open end ratchet wrenches fail to provide for both a moving jaw member and a fixed jaw member, wherein a double nut arrangement, such as in an in-line compression fitting, can be tightened or loosened. The above referenced open end ratchet wrenches also fail to provide for linear movement of the moving jaw member away from the central axis of rotation which would allow the moving jaw member to back off and release from operative engagement with the work piece so that the wrench can be removed from the work piece. My previous invention, as disclosed in U.S. Pat. No. 6,810,773, provides for theses features and advantages that are not found in the above referenced prior art wrenches. 
     Notwithstanding the benefits of my prior invention, there are instances wherein it is necessary to tightened or loosen either a single or double nut device in a tight, confined space, which requires continuous rotation of a nut element about one or more complete 360° rotations without having to remove the wrench from the nut element on the work piece. My prior invention, as disclosed in U.S. Pat. No. 6,810,773, allows for only limited rotation of the moving jaw member, either clockwise or counterclockwise about a turn of less than 360°. More particularly, the moving jaw member of my prior invention is not able to rotate continuously about a 360° path of rotation relative to the central rotational axis of the wrench mouth. Moreover, my prior invention fails to provide for a carriage return assembly that allows the moving jaw member to return to a start position, in open alignment with the mouth of the wrench, regardless of the rotated position that the moving jaw member is at just prior to returning to the start position. 
     Accordingly, there remains a need for an open end ratchet wrench that allows for selective rotation of a moving jaw member, either clockwise or counterclockwise through one or more complete 360° rotations, and which allows for linear movement of the moving jaw member away from the central axis of rotation of the wrench mouth while also allowing the moving jaw member to be returned to a start position in open alignment with the wrench mouth regardless of the rotated position of the moving jaw member. 
     SUMMARY OF THE INVENTION 
     An open end ratchet wrench includes a housing defining a handle and a head with an open mouth surrounding a central axis of rotation. The open mouth is formed to include a multi-faceted fixed jaw for engaging a congruently configured element of a work piece, such as a first element of a compression fitting. A carriage is rotatable about the central rotational axis of the mouth of the wrench and carries a moving jaw member with a multi-faceted arrangement for engaging a congruently configured element, such as a second element of a compression fitting or any type of individual multi-sided element, such as a hex nut. A squeeze lever is operable to rotate the carriage and the moving jaw member continuously about the central rotational axis, selectively in either a clockwise or counterclockwise movement, to thereby tightened or loosen either a single nut on a threaded element, or a second multi-sided element relative to a first multi-sided element. An engagement assembly operates the moving jaw member between an operable position in engagement with a multi-sided element and a retracted release position, wherein the moving jaw member backs away from the central rotational axis to release from operative engagement with the multi-sided element. A switch operated carriage return assembly spins the carriage and moving jaw member to a start position, defined by alignment of the moving jaw member with the fixed jaw member and the open mouth of the wrench, to thereby allow removal of the wrench from the work piece. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a fuller understanding of the nature of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a top perspective view of the open end ratchet wrench of the present invention; 
         FIG. 2  is a top plan view of the moving jaw member; 
         FIG. 3  is a bottom plan view of the moving jaw member; 
         FIG. 4  is a rear elevational view of the moving jaw member; 
         FIG. 5  is a top plan view of a top plate of the carriage assembly; 
         FIG. 6  is a top plan view of a first stage of the carriage assembly, normally positioned below the top plate, and including a sprocketed outer ring and an inner ring; 
         FIG. 7  is a top plan view of a second stage of the carriage assembly providing a spacer ring below the first stage; 
         FIG. 8  is a top plan view of a third stage of the carriage assembly including a ring with a stop member for stopping the return rotation of the carriage at the start position; 
         FIG. 9  is a top plan view of a lower gear member of the carriage assembly, providing a fourth stage for engagement with a carriage return assembly; 
         FIG. 10  is a top plan view of a toothed ring normally positioned in the first stage of the carriage assembly between the outer and inner rings; 
         FIG. 11  is a exploded side elevational view illustrating the functional arrangement between the moving jaw member, the top plate of the carriage assembly and the toothed ring for engaging and releasing the moving jaw member from the advanced, operative position to a retracted, release position; 
         FIG. 12  is a top plan view of the wrench, shown with a top portion of the housing, a squeeze lever and other components removed in order to illustrate various component elements with the housing of the wrench, including an arc shield for selectively controlling operational move of the moving jaw member between a clockwise rotation, a counterclockwise rotation and neutral mode and a loader finger for tightening a spin gear against a coil spring force assembly upon squeeze operation of the lever; 
         FIG. 13  is a top view of the spin gear carriage return assembly; 
         FIG. 14  is an exploded arrangement of the component parts of a plunging arm assembly; 
         FIG. 15  is a top plan view of the plunging arm assembly; 
         FIG. 16  is an exploded view showing the arc shield and a primary thumb switch; 
         FIG. 17  is an exploded top plan view of the lever and rotational pawls for engaging the sprocketed ring of the carriage assembly in order to selectively rotate the carriage assembly in either the clockwise or counterclockwise direction; 
         FIG. 18  is an exploded perspective view showing a further embodiment of the moving jaw member including a removable insert to change the wrench size of the moving jaw member; and 
         FIG. 19  is an isolated perspective view showing the wrench size adjustment insert received within the moving jaw member, and also a fixed jaw member that is adapted to receive a similar wrench size adjustment insert. 
     
    
    
     Like reference numerals refer to like parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the several views of the drawings, the open end ratchet wrench of the present invention is shown and is generally indicated as  10 . As shown in  FIG. 1 , the wrench  10  includes a housing  12  defined primarily by a handle portion  14  and an integrally formed head  18  including an open mouth  20 . In a preferred embodiment, the housing is formed to include a fixed jaw member  22 . As best seen in  FIG. 19 , the fixed jaw member  22  surrounds about the wrench mouth and has a multi-faceted configuration for engaging a first element of a work piece. The fixed jaw member  22  may also include slots  23  for receiving an insert jaw member providing for wrench size adjustment, wherein the spacing between the multi-faceted sides is changed to accommodate different sizes of a work piece, such as different hex nut sizes. 
     Referring to  FIGS. 18 and 19 , the wrench  10  further includes a moving jaw member  30  movably positionable within the mouth  20 . The moving jaw member  30  is carried on a rotatable carriage  40  that allows complete 360° rotation of the moving jaw member  30  about a central longitudinal axis  21  extending through the mouth  20  of the wrench. The moving jaw member  30  includes a multi-faceted configuration for operative engagement on a multi-sided element of a work piece, such as a hex nut or fitting. Similar to the fixed jaw member  22 , the moving jaw member may be provided with slots  33  for receiving an insert jaw member  35  for wrench size adjustment. 
     The rotational capability of the carriage  40  allows the moving jaw member  30  to remain on the multi-sided element (e.g. hex nut, or fitting) while rotating the multi-sided element continuously, as needed, to advance or retreat the multi-sided element along a threaded element while the handle  14  of the wrench is held stationary and a squeeze lever  34  of the wrench is continuously operated. The carriage assembly  40  is specifically structured for rotating the moving jaw member  30  in either a clockwise or counterclockwise rotational direction for an unlimited number of complete 360° rotations, while the moving jaw member  30  remains engaged on the multi-sided element of the work piece. 
     The moving jaw member  30  is slideably carried on the carriage assembly  40  and is movable between a retracted position, wherein the moving jaw member  30  is backed away from the multi-sided element of the work piece, and an advanced, operative position, wherein the moving jaw member  30  is moved inwardly towards the central rotational axis of the wrench mouth and into engagement with the multi-sided element of the work piece. The carriage assembly  40  is also selectively engaged with a carriage return assembly  120  (see  FIG. 13 ) in order to return the carriage  40  and moving jaw member  30  to a start position, wherein the facets of the moving jaw member  30  are aligned with the facets of the fixed jaw  22  and the mouth of the moving jaw is aligned with the open mouth  20  of the wrench, thereby allowing the wrench  10  to be completely removed from the work piece. 
     The moving jaw member  30  is slidable on dove tail guide rails  42  on a top plate  41  of the carriage  40  (see  FIGS. 3-5 ). More particularly, the dove tail guide rails  42  are received within congruently configured grooves  32  formed on a bottom side of moving jaw member  30 . A spring  43  connects between the moving jaw member  30  and the carriage  40  to urge the moving jaw member to the retracted release position, wherein the moving jaw member  30  is backed away from the central rotational axis  21  of the mouth of the wrench. Operation of a plunging arm  92  (see  FIGS. 14-15 ), as described more fully hereinafter, urges the moving jaw member  30  against the spring  43  and into locked engagement with a recessed finger  44  in the carriage assembly, to thereby hold the moving jaw member in the advanced, operative position. A sprocketed outer ring  46  and inner ring  47  (see  FIG. 6 ) comprise a first stage of the carriage assembly and are fitted below the top plate of the handle  14 . A second stage of the carriage assembly, positioned below the inner ring  47 , provides a spacer ring  48  (see  FIG. 7 ) that functions to engage friction springs on the wrench mouth, as described further hereinafter. The third stage of the carriage assembly provides a ring  50  with a stop member  51  (see  FIG. 8 ) for stopping rotation of the carriage  40  at the start position following actuation of the carriage return assembly  120 . A fourth stage of the carriage provides for a gear member  52  (see  FIG. 9 ) for engagement with the carriage return assembly  120  to allow the carriage assembly and moving jaw member  30  to spin back to the start position. A toothed ring  54  is received between the sprocketed outer ring  46  and the inner ring  47  in the first stage of the carriage. The toothed ring  54  is retained by a spring  55  (see  FIG. 10 ) which allows limited arc movement of the toothed ring relative to a remainder of the carriage assembly. The toothed ring  54  includes a bump  56  (see  FIG. 11 ) on its top surface for engaging a pivoting finger  44  on the top plate  41  of the carriage assembly  40  in order to move the pivoting finger  44  downwardly and out of engagement with a recess  57  in the bottom of the moving jaw member, thereby allowing ejection spring  43  to pull the moving jaw member  30  to the retracted release position. 
     Rotation of the carriage  40  and moving jaw member  30  is achieved by squeeze operation of the lever  34 . The lever  34  is pivotally fitted within an interior of the housing of the wrench and extends outwardly from a side of the wrench at a normally relaxed position. Squeeze operation moves the lever inwardly towards the side of the wrench and within a slotted opening  35  along the side of the wrench housing  12 . A lever return spring  37  (see  FIG. 17 ) connected between the lever  34  and the inner housing of the wrench returns the lever  34  to the relaxed position, defined by the lever  34  extending outwardly from the side of the wrench at an angle of approximately 40°. Referring to  FIG. 17 , a clockwise pawl  60  is fitted to a top end  38  of the lever  34  and is urged inwardly towards the wrench mouth by spring  61  which connects between a lower end of the pawl  63  and the top end  38  of the lever  34 . A counterclockwise pawl  66  is fitted to a mid-portion  39  of the lever  34  and is urged inwardly, towards the mouth of the wrench by a spring  67  connected between a lower end  68  of the counterclockwise pawl  66  and the mid-portion  39  of the lever  34 . Both the clockwise pawl  60  and the counterclockwise pawl  66  are provided with teeth  69   a  on arcuate pawl arms  69  for engaging the sprocketed outer ring  46  of the carriage assembly  40  in order to drive rotation of the carriage assembly either clockwise or counterclockwise, upon squeezing the lever  34 . Specifically, when the clockwise pawl  60  is engaged with the sprocketed outer ring  46  of the carriage assembly  40  and the lever  34  is squeezed, the clockwise pawl  60  urges the carriage assembly in the clockwise rotational direction which, in turn, rotates the moving jaw member  30  about the central rotational axis  21  of the mouth in the clockwise direction. Similarly, when the teeth  69   a  of the counterclockwise pawl  66  are engaged with the sprocketed outer ring  46  of the carriage assembly  40  and the lever  34  is squeezed, the counterclockwise pawl  66  is moved to drive rotation of the carriage assembly in the counterclockwise direction which, in turn, rotates the moving jaw member  30 , in the counterclockwise rotational direction about the central rotational axis  21  of the wrench mouth. 
     Referring to  FIGS. 1 and 16 , a primary thumb switch  70  is operated to control selection of the rotation of the carriage  40  and moving jaw member  30  in either the clockwise or counterclockwise directions. The primary thumb switch  70  is operable between three positions, including a right position for counterclockwise rotation, a left position for clockwise rotation, and a center neutral position. A ball bearing and detent block  71  allow the thumb switch  70  to be selectively moved and held in the selected position. The primary thumb switch  70  is mounted on a central pivot pin  72  and includes a forwardly extending finger  73  that is received within a notch  74  in the arc shield  76 . The arc shield  76  is slidable around an arc of movement relative to the mouth of the wrench. Pivoting movement of the primary thumb switch  70 , by pushing the primary thumb switch tab  75  either to the right or the left, moves the forwardly projecting finger  73  of the thumb switch  70  to urge the arc shield  76  to the left or to the right. When the projecting tab  75  of the primary thumb switch, on the top of the wrench, is moved to the first position (i.e. to the right) the forwardly projecting finger  73  of the thumb switch moves to push the arc shield  76  to the left, thereby disengaging the clockwise pawl  60  from the sprocketed outer ring  46  of the carriage assembly  40  and moving the counterclockwise pawl  66  into engagement into the sprocketed outer ring  46 . Upon subsequent squeeze and release operation of the lever  34 , the counterclockwise pawl  66  will drive rotation of the carriage assembly  40  and the moving jaw  30  in the counterclockwise rotational direction. Movement of the projecting tab  75  on the primary thumb switch  70  to the left position urges the arc shield  76  to the right, thereby disengaging the counterclockwise pawl  66  from the sprocketed outer ring  46  of the carriage assembly  40  and allowing the spring  61  of the clockwise pawl  60  to urge the clockwise pawl into engagement with the sprocketed outer ring  46  of the carriage  40 . Upon subsequent squeeze and release operation of the lever  34 , the clockwise pawl  60  drives rotation of the carriage assembly  40  and the moving jaw  30  in the clockwise rotational direction about the central rotational axis  21  of the wrench mouth. It is important to note that the toothed arms  69  of the clockwise and counterclockwise pawls are longer than the mouth (i.e. gap) of the moving jaw member  30  to thereby allow the pawls  60 ,  66  to always remain in at least partial engagement with the sprocketed outer ring  46  on the carriage so that the carriage  40  can be continuously rotated in either direction. 
     Movement of the projecting tab  75  of the primary thumb switch  70  to the center position serves to move the arc shield  76  to a neutral position, wherein both the clockwise pawl  60  and the counterclockwise pawl  66  are disengaged from the carriage assembly  40 . Referring to  FIG. 12 , movement of the primary thumb switch  70  to the neutral position further causes the arc shield  76  to move an advancing inhibitor finger  78  against a spring force of a pivoting push rod  79  that is received through a slotted arrangement of the advancing and inhibiting finger. Movement of the pivoting push rod  79 , in this neutral position, aligns the pivoting push rod  79  with an advancing finger  80  on the top end of the lever  34 . Upon squeeze operation of the lever  34  from a normally relaxed position to the squeezed position, with the primary thumb switch  70  the neutral position, the advancing finger  80  pushes the pivoting pushrod  79  which, in turn, urges an activator bar  82  through a short arc of movement. This causes spring loaded jaw ejection fingers  83  on the activating bar  82  to rise and engage the toothed ring  54  on the carriage, urging the toothed ring  54  against the spring  55  and moving the bump  56  on top of the toothed ring against the jaw holder finger  44  to disengage the holder finger  44  from the moving jaw member  30 , and thereby allowing the moving jaw member  30  to retract to the released position in response to the force of the jaw ejection spring  43 . 
     In addition to releasing the moving jaw member  30  from the work piece, the engagement assembly is operable to move the moving jaw member  30  back to the advanced, operable position for engagement on the multi-sided element of the work piece. Specifically, the engagement assembly includes a plunging arm assembly  90  supported on a plate  91  within the wrench, as shown in  FIGS. 14-15 . The plunging arm assembly  90  includes a sleeve  93  for containing a plunging arm  92  against the force of a spring  95  connecting between the plunging arm  92  and the mounting plate  91 . The spring  95  is arranged to urge the plunging arm  92  outwardly from a forward end of the sleeve and into contact with a rear portion of the moving jaw member  30  to thereby push the moving jaw member  30  inwardly relative to the central location axis  21  of the wrench mouth  20 . More particularly, the plunging arm  92  applies a force to the rear face of the moving jaw member  30  to cause the moving jaw member to slide on the dove tail guide rails  42  of the carriage assembly  40  until the jaw holder finger  44  engages the recess  57  on the bottom side of the moving jaw member  30 . With the holder finger engaged within the recess  35 , the moving jaw member  30  is releasably locked in the advanced, operable position. 
     The plunging arm  92  is normally loaded within the sleeve  93 , against the force of the spring  95 , and held by a hooked tip  97  of a pivoting claw  96 . To fire the plunging arm  92  forwardly, thereby returning the moving jaw member  30  to the operable position, the secondary thumb switch  100  is pushed forward towards the mouth of the wrench (see  FIG. 1 ). This causes a leg  102  of the secondary thumb switch  100  to move a pivoting element  103 , against the force of a spring  104 , which, in turn, and causes the claw  96  to pivot and release the hooked tip  97  from the engagement with the plunging arm  92 . Once the hooked tip  97  is released from the plunging arm  92 , the spring  104  immediately pulls the plunging arm  92  forward in a rapid shooting action. The forward distal tip of the plunging arm  92  strikes the rear face of the moving jaw member  30 , forcing the moving jaw member forwardly, in rapid movement, to the advanced, operable position, wherein the jaw holder finger  44  catches the recess  57  on the bottom of the moving jaw member  30  (see  FIGS. 3 and 5 ). Upon the next successive squeeze operation of the lever  34 , the plunging arm  92  is reloaded within the sleeve  93  and locked into the loaded position by the claw  96  which is normally urged into interlocking engagement with the plunging arm  92  by the spring loaded pivoting element  103 . Specifically, a roller element  105  on the squeeze lever  34  engages the back edge of a plunging arm loader hook  106 . The plunging arm loader hook  106  grabs a pin  107  extending perpendicularly from a rear portion of the plunging arm  92 . By squeezing the lever  34 , the roller  105  pushes the plunging arm loader hook  106  about a pivot pin  108  which, in turn pulls the pin  107  on the plunging arm  92  back and retracts the plunging arm  92  into the sleeve  93 . When the plunging arm  92  is fired, the plunging arm loader hook  106  serves to stop the plunging arm  92  in its forward movement so that the plunging arm  92  does not fully exit the sleeve. 
     As noted above, a carriage return assembly  120  functions to spin the carriage assembly  40  and the moving jaw member  30  back to the start position so that the wrench can be placed onto or moved from the work piece. When it is desired to spin the carriage  40  assembly and moving jaw member  30  back to the start position, the secondary thumb switch  100  is moved backwards, away from the mouth of the wrench. Backwards movement of the secondary thumb switch  100  causes the leg  102  to trip a catch element  110  which normally holds the carriage return assembly  120  in a stowed position. The carriage return assembly  120  is mounted on a plate  122  that includes opposite arched arms  124 , 126  structured and disposed to surround the mouth of the wrench, within the wrench housing. The carriage return assembly plate  122  accommodates a main spin gear  130  and a pair of secondary spin gears  132 , 134  drivingly engaged with the teeth  131  of the main spin gear  130 . The plate  122  of the carriage return assembly  120  is mounted within the housing and is longitudinally movable a limited distance. Specifically, mounting slots  136  on the plate  122  are specifically sized and positioned to limit forward and rearward movement of the plate. Screws  138  are received through the slots  136  and are fixed to the housing, allowing the plate  122  of the carriage return assembly  120  to move as defined by the length of the slots  136  relative to the permitted movement of the mounting screws  138  within the slots. In the retracted, stowed position, the pivoting catch member  110  is engaged within an aperture  140  in the rear of the plate  122 . A spring  142  connecting between the plate  122  of the carriage return assembly and the housing  12  urges the entire carriage return assembly  120  forward, limited by the permitted movement of the mounting screws  138  within the longitudinal slots  136 . The catch member  110  holds the plate  122  in the stowed position, against the force of the spring  142 . 
     Referring to  FIGS. 12 and 13 , the main spin gear  130  of the carriage return assembly  120  is loaded against the force of a flat coil spring  144  that connects at one end to the plate  122  and an opposite end to a hub  146  fitted to the main spin gear  130  about its center rotational axis. The hub  146  serves to rotatably mount the main spin gear  130  to the plate  122 . With each squeeze operation of the lever  34  of the wrench, a spring biased spin gear loader finger  150  is pulled. The tip  152  of a spring gear loader finger  150  engages the outer toothed surface  131  of the main spin gear  130  to rotate the main spin gear  130  against the force of the flat coil spring  144  with each squeeze of the main operating lever  34  of the wrench. A spin gear holder spring element  154  also engages in the main spin gear  130  to hold the main spin gear  130  against the wound coil force of the flat coil spring  144  after each rotational loading movement as the loader finger  150  is pulled to rotate and load the main spin gear  130  with each squeeze operation of the lever. Eventually, the flat coil spring  144  becomes fully loaded and the spring biased spin gear loader finger  150  yields to a force of a relief spring  156  upon further squeeze operation of the lever. Specifically, rather than rotating the main spin gear  130  when the flat coil spring  144  is fully loaded, the spin gear loader finger  150  nearly extends out from a spring loader tube  151  with each squeeze operation of the wrench lever, and then returns to its normal, relaxed position, due to the force of the relief spring  156 , as the lever  34  of the wrench is released back to its relaxed position. This prevents overloading of the flat coil spring  144 . 
     When it is desired to return the carriage assembly  40  and moving jaw member  30  to the start position, the moving jaw member  30  is first retracted to the release position, in the manner described above. Next, the secondary thumb switch  100  is pushed backwards, away from the mouth of the wrench, to trip the catch element  110 , thereby releasing the plate  122  of the carriage return assembly  120 . This also releases the spin gear holder spring element  154  and the spring gear loader finger  150  from engagement with the main spin gear  130 . Accordingly, the entire carriage return assembly  40  moves forward in rapid action, while the main spin gear  130  is rotated due to the recoil action of the loaded flat coil spring  144 . Rotation of the main spin gear  130  serves to drivingly rotate the secondary spin gears  132 , 134 . With the carriage assembly  40  moved to the forward, operable position, the secondary spin gears  132 , 134  engage the lower gear ring  52  on the carriage assembly  40 , thereby spinning the entire carriage assembly  40  until the rotating stop member  51  on the third stage of the carriage assembly strikes a fixed stop member  158  on the carriage return assembly plate  122 , thereby stopping and holding the carriage assembly  40  in the start position with the moving jaw member  30  aligned with the open mouth  20  of the wrench. Upon the next successive squeeze operation of the wrench lever  34 , a spin plate loading pin  160  connecting to the lever pulls the plate  122  of the carriage return assembly  120  back, against the force of the spring  142 , until the catch element  110  engages within the aperture  140  of the plate  122 , thereby holding the carriage return assembly  120  in the stowed position. In this position, friction springs  164 , 166  at the forward distal ends of the arch arms  124 , 126  of the plate engage the second stage spacer ring  48  of the carriage assembly  40  to prevent free rotation of the carriage assembly  40  and moving jaw member  30 . 
     While the present invention has been shown and described in accordance with preferred and practical embodiments thereof, it is recognized that departures from the instant disclosure are fully contemplated within the spirit and scope of the invention.