Patent Abstract:
A roller clutch mechanism of a reversible ratchet tool is configured to include a biasing and reversing mechanism for biasing rollers in the roller clutch mechanism. A cage member of the roller clutch mechanism locates rollers in either a clockwise or counterclockwise position based on a selective position of the reverser mechanism. The reverser mechanism applies a constant bias to the cage member so that the rollers are constantly biased and quickly engage between the ratchet body and the drive head. The constant bias applied to the cage member reduces the ratcheting angle for improved performance of the reversible ratchet tool.

Full Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present application relates generally to a tool for applying torque to an object. More particularly, the present application relates to a roller clutch mechanism for a reversible ratchet-type tool. 
       BACKGROUND OF THE INVENTION 
       [0002]    Reversible ratchet tools, such as socket wrenches and drivers, are commonly used in automotive, industrial and household applications to install and remove threaded fasteners and to apply an amount of torque and/or angular displacement to work pieces, such as a threaded fasteners, for example. Various mechanisms within ratchet tools are configured to prevent rotation of a ratchet drive head relative to the tool handle in one direction and to allow rotation of the ratchet head relative to the tool handle in the opposite direction. This allows the drive head to apply torque to a fastener through large angles by repeating smaller angular movements of the tool handle and without disengaging the tool head from the fastener after each movement. For conventional ratchet tools, the smaller angular movements on each stroke must reach at least a minimum angular displacement to overcome backlash and cumulative dimensional variations of the tool components within manufacturing tolerances. Backing the handle of a ratchet tool through some minimum angular displacement after each movement provides sufficient rotation of the ratchet body relative to a drive member to overcome the backlash and dimensional variations to configure the tool for applying a torque on a following movement. 
         [0003]    Ratchet tools which require an excessive angular displacement of the handle may not be usable in confined spaces. It is thus desirable to reduce or eliminate the minimum angular displacement constraint, i.e., ratchet angle, of conventional ratchet tools in order to allow use of the tool in locations where angular displacements of the handle may be obstructed. 
       SUMMARY OF THE INVENTION 
       [0004]    Aspects of the present application include a roller clutch mechanism of a reversible ratchet tool that reduces relative rotation between the ratchet body and a drive head. The reversible ratchet tool includes a biasing and reversing mechanism for a roller clutch. A cage member of the roller clutch mechanism locates rollers in either a clockwise or counterclockwise position based on a position of the reversing mechanism. The reverser mechanism applies a constant bias to the cage member so that the rollers are biased to quickly engage between the ratchet body and the drive head. The constant bias applied to the cage member reduces the ratcheting angle for improved performance of the reversible ratchet tool. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated. 
           [0006]      FIG. 1A  is a front, perspective exploded view illustrating a reversible ratchet apparatus in accordance with an embodiment of the present application. 
           [0007]      FIG. 1B  is a rear, perspective exploded view illustrating a reversible ratchet apparatus in accordance with an embodiment of the present application. 
           [0008]      FIG. 2  is an enlarged plan view illustrating rollers binding between a drive member an a ratchet body according to an aspect of the present application. 
           [0009]      FIG. 3A  is a plan view of a reversible ratchet apparatus configured to apply torque in a first direction according to an aspect of the present disclosure. 
           [0010]      FIG. 3B  is a plan view of the reversible ratchet apparatus of  FIG. 3A  configured to apply torque in a second direction according to an aspect of the present disclosure. 
           [0011]      FIG. 4  is a plan view of biasing members engaged between a reverser sleeve and a cage member in a reversible ratchet apparatus according to aspects of the present disclosure. 
           [0012]      FIG. 5  is a flow chart depicting a method of configuring a ratchet drive according to aspects of the present disclosure. 
       
    
    
       [0013]    It should be understood that the comments included in the notes as well as the materials, dimensions and tolerances discussed therein are simply proposals such that one skilled in the art would be able to modify the proposals within the scope of the present application. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0014]    While this invention is susceptible of embodiments in many different forms, there is shown in the drawings, and will herein be described in detail, a preferred embodiment of the invention with the understanding that the present application is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to embodiments illustrated. 
         [0015]    An illustrative embodiment of a reversible ratchet tool according to aspects of the present disclosure is described with reference to  FIGS. 1A and 1B . In an embodiment, a reversible ratchet tool  100  includes a ratchet body  102 , a cage member  108  sized to fit and disposed within the ratchet body  102 , a reverser sleeve  116  sized to fit coaxially disposed within the cage member  108 , and a drive member  104  including an axle portion  105  sized to be rotatably contained by the reverser sleeve  116 . A number of rollers  106  are constrained by the cage member  108  between an inner surface  118  of the ratchet body  102  and the drive member  104 . According to an aspect of the present disclosure, the drive member  104  and the reverser sleeve  116  are selectively constrained in either of a first angular displacement or a second angular displacement relative to each other. At least one biasing member  110  is configured to exert a substantially continuous rotational biasing force between the reverser sleeve  116  and the cage member  108 . 
         [0016]    In one example, the biasing member  110  may consist of a pair of compression springs  110 ,  111  as shown in  FIGS. 1A and 1B . According to an aspect of the present disclosure, the cage member  108  is configured to shift the rollers  106  from a corresponding first position on the drive member  104  to a corresponding second position on the drive member  104  when an angular displacement between the drive member  104  and the reverser sleeve  116  is shifted from the first angular displacement to the second angular displacement. A reverser lever (not shown) may be coupled to the reverser sleeve  116  or may be formed together with the reverser sleeve  116  as a single component, for example. 
         [0017]    The rollers  106  are cylindrically shaped and sized to selectively prevent relative motion between the ratchet body  102  and the drive member  104  only in a first direction of rotation when the rollers are in their corresponding first positions, and to prevent relative motion between the ratchet body  102  and the drive member  104  only in a second direction of rotation opposite the first direction of rotation when the at rollers are in the corresponding second positions. 
         [0018]    According to aspects of the present disclosure, the ratchet body  102  includes an inner surface  118  defining an inner wall of a circular aperture  120 . In the illustrative embodiment, the cage member  108  includes an annular base  122  and a plurality of axial fingers  124  extending from one side of the annular base  122 . The annular base  122  is sized to fit and be coaxially disposed within the circular aperture  120 , wherein the fingers  124  substantially avoids contact with the inner surface  118 , to cooperatively define a cage aperture  126 . In this embodiment, a tab  134  extends radially from the annular base into the cage aperture  126 . 
         [0019]    In an illustrative embodiment, the reverser sleeve  116  is a semi-annular reverser sleeve including an outer semi-annular wall  128  sized to fit coaxially within the cage aperture  126  and including an inner semi-annular wall  130  defining a first portion of a central aperture  132 . The reverser tab  134  defines a second portion of the central aperture  132  having a same diameter as the first portion of the central aperture  132 . In one example, according to an aspect of the present disclosure, the semi-annular reverser sleeve  116  includes a first end  136  and a second end  138 . A first biasing member  110  is engaged between the first end  136  and the tab  134 . A second biasing member  111  is engaged between the second end  138  and the tab  134 . 
         [0020]    In the illustrative embodiment, the drive member  104  includes the axle portion  105  sized to be rotatably contained by the central aperture  132  and a drive body coaxial with the axle portion. According to an aspect of the present disclosure, the drive body  140  includes a scalloped outer surface  142 . The drive member  104  may also include a drive lug  144  extending from the drive body  104  and coaxial with the axle portion  105 . In one example, the drive lug  144  may be configured as a square socket drive. In other embodiments, the drive lug  144  may be any of various commonly known ratchet drive configurations, such as a screw driver head, for example. Other embodiments may be configured with a drill chuck, box end wrench head or a socket in place of the drive shaft  144 , for example, without departing from the scope and spirit of the present application. 
         [0021]    According to an aspect of the present disclosure, at least one engagement member is engaged between the drive member  104  and the reverser sleeve  116 . The engagement member is configured to constrain the drive member  104  and the reverser sleeve  116  in either of a first angular displacement or a second angular displacement relative to each other. For example, in the illustrative embodiment, the drive member  104  includes a shoulder  146  (see  FIG. 1B ) facing the reverser sleeve  116 . The shoulder  146  includes a pocket  148  sized to retain a detent spring  112 . The reverser sleeve  116  includes at least two detent cavities  150  facing the shoulder  146  and angularly displaced from each other. The engagement member consists of a detent ball  114  sized to fit in either one of the detent cavities  150  and the detent spring  112 . The detent spring  112  is at least partially retained in the pocket  148  and compressed between the detent ball  114  and the drive member  104 . 
         [0022]    Engagement between the ratchet body  102 , the rollers  106  and the drive member  102  is described with reference to  FIG. 2 . In order for the ratchet tool  100  to apply a torque from the ratchet body  102  to the drive member  104 , the rollers  106  are frictionally wedged between the inner surface  118  of the circular aperture  120 . In the arrangement shown in  FIG. 2 , the drive member  104  is allowed to freely rotate counter-clockwise with respect to the ratchet body  102 , but locks-up when rotated in a clockwise direction with respect to the ratchet body  102 , thus imparting torque from the ratchet body  102 . 
         [0023]    According to aspects of the present disclosure, the rollers  106  are each constrained between a corresponding pair of fingers  124  of the cage member  108 . The rollers  106  are also constrained between the inner surface  118  of the circular aperture  120  and the scalloped surface  142  of the drive member  104 . The fingers  124  are configured to shift the rollers  106  from a corresponding first ramp  152  on the scalloped surface to a corresponding second ramp  154  on the scalloped surface when an angular displacement between the drive member  104  and the semi-annular reverser sleeve  116  is shifted from the first angular displacement to the second angular displacement. The fingers  124  of the cage member  108  keep each roller  106  in contact with the inner surface  118  and with either the corresponding first ramp  152  or the corresponding second ramp  154 . 
         [0024]    According to an aspect of the present disclosure, the rollers  106  are sized to respectively bind between the first ramps  152  and the inner surface  118  of the ratchet body  102  to prevent relative motion between the ratchet body  102  and the drive member  104  only in a first direction of rotation when the rollers  106  respectively engage and bind the corresponding first ramps  152 , and to respectively bind between the second ramps  154  and the inner surface  118  of the ratchet body  102  to prevent relative motion between the ratchet body  102  and the drive member  104  only in a second direction of rotation opposite the first direction of rotation when the rollers  106  respectively engage and bind the corresponding second ramp  154 . 
         [0025]    To reverse the free-spinning and driving directions of the roller clutch mechanism in the reversible ratchet tool  100 , the cage member  108  is rotated clockwise with respect to the drive member  104  so fingers  124  keep the rollers  106  in contact with the inner surface  118  of the ratchet body  102  and the second ramp  154 . 
         [0026]      FIG. 3A  is an illustration of a reversible ratchet apparatus  100  configured to apply torque in a first direction according to an aspect of the present disclosure. As shown in  FIG. 3A , the drive member  104  is prevented from rotating clockwise with respect to the ratchet body  102 . Thus, torque may be transmitted from the ratchet body  102  to the drive member  104  by counterclockwise motion of the ratchet body. 
         [0027]      FIG. 3B  is an illustration of a reversible ratchet apparatus  100  configured to apply torque in a second direction according to an aspect of the present disclosure. As shown in  FIG. 3B , the drive member  104  is prevented from rotating counterclockwise with respect to the ratchet body  102 . Thus, torque may be transmitted from the ratchet body  102  to the drive member  104  by clockwise motion of the ratchet body. 
         [0028]      FIG. 4  is an illustration of the reversible ratchet apparatus  100  showing biasing members  110 ,  111  engaged between a reverser sleeve  116  and a cage member  108  according to aspects of the present disclosure. In  FIG. 4 , the drive member  104  is hidden for clarity. 
         [0029]    Although a reverse lever could be coupled in direct contact with the cage member  108  to facilitate selectively switching between the two cage positions, normal manufacturing tolerances would lead to a “sloppy” action with an unacceptable amount of handle travel between ratcheting strokes. In the disclosed embodiments, a bias member  110 ,  111 , such as a spring, is configured to provide a continuous rotational bias between the reverser sleeve  116  and cage member  108 . 
         [0030]    The reverser sleeve  116  may be selectively engaged in one of two detent positions defined by the detent ball  114  and detent spring  112  being disposed in either of the two detent cavities  150  in the reverser sleeve  116 . The biasing members  111 ,  110  push against the reverser sleeve  116  and cage member  108  to provide positive pressure between fingers  124  of the cage member  108  and rollers  106 . This reduces or minimizes excessive free movement or “slop” in the ratcheting action. 
         [0031]    Another aspect of the present disclosure includes a method for reducing backlash in a reversible ratchet tool. Referring to  FIG. 5 , in block  502 , the method includes configuring a circular array of rollers within a circular roller cage member for rotation around an axis within a ratchet body. In block  504 , the method includes configuring a semi-annular reverser sleeve within the ratchet body for rotation around the axis. In block  506 , the method includes configuring at least one biasing member to exert a continuous rotational biasing force between the reverser sleeve and the cage member and about the axis. At block  508 , the method includes configuring the semi-annular reverser sleeve in one of two positions angularly displaced from each other about the axis. At block  510 , the method includes configuring a drive member within the reverser sleeve for rotation about the axis. At block  512 , the method includes engaging the semi-annular reverser sleeve to a drive member to prevent relative angular displacement between the semi-annular reverser sleeve and the drive member. 
         [0032]    As used herein, the term “coupled” or “communicably coupled” can mean any physical, electrical, magnetic, or other connection, either direct or indirect, between two parties. The term “coupled” is not limited to a fixed direct coupling between two entities. 
         [0033]    The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of applicants′ contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.

Technology Classification (CPC): 1