Abstract:
A low profile locking socket drive universal joint uses a compact locking mechanism with a control bar and a transverse actuator assembly connected to a sleeve to lock a socket to a drive stud with dual function tensioning springs, flexing clevis arms, movable spring seat and closely spaced universal coupler axes all contributing to a short, fatigue resistant universal joint that additionally supports sockets close the drive axis at rest to operator advantage and limits movement skewed to the drive axis to substantially 45°.

Description:
CLAIM OF PRIORTY  
       [0001]     This application claims priority based on Provisional Application Ser. No. 60/563,729 filed Apr. 20, 2004, and having the same title and inventor. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     A low profile universal joint is used in connection with socket wrench sets that enables application of force to a fastener at an angle off the axis of rotation of the fastener by turning a wrench handle such as ratchet or breaker bar. The low profile universal joint enables the locking of a socket to the universal joint and the release of the socket by selectively retracting the circumferential sleeve, accomplished in a length equivalent to the length of a non-locking universal joint.  
         [0004]     2. Description of Related Art  
         [0005]     Releasing ratchet handles, locking socket wrench extensions and a few locking universal joints are known. The ends for locking extensions have been adapted to universal joints having a length significantly greater than standard universal joints, such as shown in  FIG. 4 . This prior art feature provides a disadvantage in compactness.  
         [0006]     Locking solutions have generally included three locking pins which must be depressed with a probe, hand-held pin or other device as used for many years in impact tools, central axis tapered pins and surface channel control bars.  
         [0007]     The typical control bar solutions on extensions, including short bodies pinned to longer extensions include the Nickipuck family of patents, U.S. Pat. Nos. 4,480,511, 4,768,405, 4,805,549, 4,938,107 and 5,042,332.  
         [0008]     These patents are incorporated by reference as if fully set forth herein.  
         [0009]     The prior art non-locking universal joint shown in the drawings is typical of a high quality socket drive tool, and for a ⅜″ drive socket set has a length “Lpa” of about 1⅝″ and a width “Wpa” of about 11/16″, or a ratio of about 2.4. Other prior art non-locking socket drive tools have L/W ratios of up to about 3.  
         [0010]     Other prior art includes alternatives showing locking universal joints, but all these appear to have central pins and are believed to be neither as compact as, nor as functional in locking and retaining sockets as the present disclosure.  
       SUMMARY OF INVENTION  
       [0011]     A socket driving universal joint combines a number of features.  
         [0012]     The universal joint has semi-automatic locking. A locking sleeve and mechanism permits selective releasing of a fastener driving member such as a socket. In addition to locking and releasing, the universal joint limits the angle of skew of the driving, male end from the axis of the driven, female end. Nevertheless the universal joint has adequate flexibility to impart driving torque under load with resistance to flexibility to avoid loss of directional control while attaching and detaching a socket to a fastener. The tension spring and stressed clevis arm arrangement provides improved performance in fatigue resistance. This is accomplished in a compact length through the use of a universal coupling member with overlapping pin screw holes. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is an elevational view of a universal joint.  
         [0014]      FIG. 2  is an exploded perspective view of the universal joint.  
         [0015]      FIG. 3  is an exploded elevational view of the universal joint.  
         [0016]      FIG. 4  is a perspective view of a standard, non-locking Universal joint. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0017]     A locking universal joint  10  receives rotative force from a ratchet handle (not shown) applied to a female driven end  11 , the torque being transmitted through the universal joint  10  to a driving male end  14 . In end  14 , slide key  16  positively locks the socket S in place by displacing lock ball  18  transversely. Manually actuated release sleeve  20  moves the slide key  16  against a lock spring  22  urges the slide key  16  upward, against intermediate ball  24  in turn applying load on lock ball  18 .  
         [0018]     Coupling member  26  is tensioned by large tension spring  28  and small tension spring  30  against a floating saddle and spring stop  32  which seats on driven end  11 .  
         [0019]     Driving member or male end  14  has a body  40  with left and right clevis arms  42 ,  44  defining a coupler receiving area between them. A ratchet receiving receptacle  45  will receive the common square drive or alternative drives such as hex or spline, star, Torx or other similar configurations. While direct receipt of a drive handle is contemplated, one of ordinary skill will understand that various combinations of socket drive tools can be used at various stages—thus the Universal joint could be between two extensions, between a drive handle and an extension, between an extension and a socket, as well as the simple drive handle—Universal joint—socket arrangement. Each arm  42 ,  44  has a threaded pin aperture  46 ,  48 . Saddle  30  will actually be rotated from the view shown for clarity in  FIG. 3  so that projection  50  fits in and spans receptacle  45 .  
         [0020]     Spring seat  52  receives springs  26 ,  28 . Springs  26  and  28  are coil springs that fit within one another in a telescoping fashion to use the fatigue resistance of coil springs in a compact arrangement. Prior art typically applies tension in universal joints with fatigue prone lock washer style springs.  
         [0021]     Universal coupling member  24  has left and right bosses  60 ,  62  and front and rear bosses  64 ,  66 , defining lands  68 ,  70  between them. The terminology with respect to these members, left, right, front and rear is used with reference to the drawings, it being understood the member rotates in use and the orientation changes. Thus, the terminology is only used with reference to the drawings and is not intended to limit the invention. Springs  26 ,  28  bear on land  68 . Within bosses  60 ,  62  are pin receiving apertures  72 ,  74 . Within bosses  64 ,  66  are apertures  76 ,  78 . Set screws  80 ,  82  are received in threaded apertures  46 ,  48  and continue projecting inwardly threadily connecting apertures  72 ,  74 . The threads cut in the respective apertures  46 ,  72  and  48 ,  74  are synchronized when cut to provide a continuous spiral path taking into account intolerances between the respective members. Additionally, rotation of the universal joint  10  about the axis of the screws and apertures will actually tighten the threaded assembly flexing arms  42 ,  44  slightly. The floating nature of saddle  30  thereby provides a fatigue resistant structure. The flexing of arms  42 ,  44  thus provides an additional resistance to the universal joint falling off the central axis, thus easing operation such as when a mechanic attempts to attach a drive socket in a remote area.  
         [0022]     Sleeve  20  has an interior wall  90  relieved to provide a groove  92 . Wall  90  closely conforms to the surface of driving member male end  12 . Slide key  16  is formed substantially in an inverted “T” shape.  
         [0023]     Slide key  16  has a vertical control bar structure  100  and a transverse actuator structure  102 . Control bar structure  100  has a ramp  104  that directly contacts intermediate ball  106 . Ball  106  transmits force between retainer ball  18  and control bar structure  100 . Outer wall  108  will, when the device is in a locked position bear on an interior wall of a socket. Notch  110  will engage the edge of a socket to permit pushing the socket on the device to retract the locking mechanism. Thus, the socket can be placed on the device without retracting the sleeve  20 . This operation is described in greater detail in the Nickipuck patents cited above and incorporated by reference herein in their entirety.  
         [0024]     Actuator  102  has two opposed arms  112 ,  114  connected by a transverse cross piece  116  defining thereunder a spring ram  118  that receives spring  22 . Stops  120 ,  122  provide limitation of motion when in the assembled condition and the locked condition by providing surfaces upon which arms  42 ,  44  abut when the universal joint is deflected to a maximum of 45°. As force transmission through the universal joint is generally ineffective past about 45°, it is a typical design flaw in standard universal joints that the universal joint can bend to an extreme angle whereby it is neither easy for an operator to align sockets nor is it feasible for the operator to transmit torque. All surfaces and arms are formed and arranged with this limitation in mind.  
         [0025]     Driving member or male end  12  has a body  130  and clevis arms  132 ,  134 . Arms  132 ,  134  have threaded apertures  136 ,  138  that receive set screws  140 ,  142  in the same manner at arms and apertures  42 ,  44 ,  46 ,  48  and the connection to threaded aperture  76 ,  78  and flexing of arms  132 ,  134  is affected in the same manner.  
         [0026]     At the end of body  130  is a projecting drive member  144 . Drive member  144  and body  130  are formed with channel  146  in which control bar portion  100  moves and is guided in channel  146  to engage and disengage ball  18  through ball  106 . Channel  146  intersects transverse actuator channel  148  so that arms  112 ,  114  being engaged in slot  92  to permit the longitudinal movement of control bar portion  100 .  
         [0027]     Sleeve  20  being circular and corresponding closely to the diameter of body  130  must actually be distorted out of round to receive arms  112 ,  114 . The elastic properties of the material then permit sleeve  130  to return to the circular configuration for assembly. As the aforementioned components are assembled, tension springs  150 ,  152  are received in apertures  153  located just inside arms  132 ,  134 . Springs  150 ,  152  bear directly on bosses  64 ,  78  to provide additional tension tending to urge the axes of members  12 ,  24  and  14  into a straight alignment. As discussed above, this provides assistance to the operator in permitting better control and “aiming” of a drive socket to the line with the fastener in a difficult to reach location.  
         [0028]     Universal coupling member  24  is formed with the axes of apertures  72 ,  74  and  76 ,  78  perpendicular. The spacing of the axes is such that at the diameter of the apertures and set screws, there would be an overlap of the respective cylinders defined by the extended diameters. Thus, by comparison to prior art universal joints using pins, a much closer spacing of the axes  72 ,  74  and  76 ,  78  can be accomplished. Should pins have been used, the pins would interfere with one another because their outer surfaces would overlap. The use of set screws, therefore, enables a much closer spacing. p Thus, the length L of the low profile locking universal joint relative to width W can be a ratio of less than three, optimally about 2.66 or less. Compared to prior art which considers a ratio of 5 to be advantageous, the instant invention is far superior.  
         [0029]     While the present invention has been disclosed and described with reference to a single embodiment thereof, it will be apparent, as noted above that variations and modifications may be made therein. It is also noted that the present invention is independent of the particular tools used to impart rotational force and the particular tools driven, being not limited to those tools. It is, thus, intended in the following claims to cover each variation and modification that falls within the true spirit and scope of the present invention.