Abstract:
A locking mechanism for joining an elongate member to an assembly may include a frame, clamp, actuator and link between the clamp and actuator. Stop surfaces on the clamp and actuator cooperate to secure the elongate member. A pin and the force transmitted by a compression spring may further be provided for additional security. The link between the clamp and actuator retracts the clamp permitting the elongate member to be detached from the assembly. A linear actuator may be operatively disposed between the frame and the actuator for opening and closing the clamp about the elongate member.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
     This is a continuation-in-part of application Ser. No. 13/169,068, filed Jun. 27, 2011. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to locking mechanisms. More specifically, the present invention relates to locking mechanisms designed to attach in a secure fashion elongate members such as a bar, pipe, rail or the like to an assembly. 
     II. Related Art 
     Various hitches and clamping arrangements have been used to couple farm implements to a tractor or attachments to a work vehicle. Likewise, various clamping arrangements have been used in the construction of scaffolding and other assemblies used in the building construction, maintenance and repair industries. Various clamping arrangements have also been used in connection with watercraft and the riggings for watercraft. Various clamping arrangements have been used in the assembly of sporting, camping and other recreational equipment. Most such clamping arrangements are designed for the specific application. Many require substantial time and effort to use the clamp to form an attachment. Many such clamps also typically require periodic inspection and maintenance to ensure safety. Thus, there continues to exist in the art a real need for a clamp having broad application which is inexpensive to construct, easy to operate and provides the required margin of safety. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a locking device for coupling an elongate member such as a bar, rail, tube, pipe or the like to an assembly. The locking device comprises an outer frame fixed to and extending from the assembly. The outer frame comprises one or more side plates. When more than one side plate is used, the side plates extend in a parallel spaced relation to each other from a portion of the assembly. Typically, two such side plates are used. Each of the side plates includes an elongate member receiving recess. 
     The locking device also includes a clamp comprising at least one clamp plate. Typically two clamp plates are used. Each of the clamp plates includes a member retention surface and a stop surface. A rotating link coupler is also attached to at least one of the clamp plates. This rotating link coupler includes an orifice surrounded by an engagement surface. The clamp is attached to the outer frame so the clamp is rotatable relative to the outer frame. 
     The locking device also includes an actuator comprising at least one actuator plate. Typically, two are used. The actuator plates have a second stop surface. At least one rotating link coupler is also attached to the actuator. This rotating link coupler also includes an orifice surrounded by an engagement surface. The actuator is coupled to the outer frame so that the actuator is rotatable relative to the outer frame. 
     The clamp also includes a bolt and a compression spring. The shaft of the bolt extends between the rotating link coupler of the clamp and the rotating link coupler of the actuator. The compression spring surrounds the shaft of the bolt such that one end of the spring engages the engagement surface of the rotating link coupler of the clamp and the second end of the spring engages the engagement surface of the rotating link of the actuator. 
     The locking device is used by positioning an elongate member such as a bar, pipe, rail or the like in the elongate member receiving recess(es) of the outer frame. The actuator is then rotated in a first direction which causes the bolt and spring arrangement to rotate the clamp into a first position. Upon further rotation of the actuator in the first direction, the actuator, clamp and bolt and spring arrangement reach an over center position such that the clamp locks the elongate member in the elongate member receiving recesses of the frame. Rotation of the actuator in the second direction causes the bolt and spring arrangement to rotate the clamp into a second position freeing the elongate member so that it can be removed from the elongate member receiving recess. 
     Advancing the actuator into the over center position will sufficiently secure the elongate member in most applications This is because the spacing between the actuator plates and the clamp plates are such that forces imparted upon the clamp plates that might cause the clamp to open instead cause the stop surfaces of the clamp plates to engage the stop surfaces of the actuator to prevent opening of the clamp. An additional margin of safety can be provided using a safety pin having a shaft. When the clamp is in the closed position, this pin can be inserted into a hole through a side plate of the outer frame such that the shaft engages a first safety pin engagement surface on the actuator to prevent rotation of the actuator. Likewise, the clamp can be held in the open position by inserting the safety pin through the same hole and engaging a second safety pin engagement surface on the actuator. 
     When multiple plates are used to form the clamp and actuator, spacers may be placed between the plates of the clamp and similarly spacers can be positioned between the plates of the actuator to retain such plates in the proper spaced relationship. A handle may also be provided as a part of the actuator to provide an appropriate mechanical advantage when moving the actuator. One or more stops which also engage the stop surfaces of the actuator and/or clamp may also be provided to prevent over rotation of the actuator and clamp in either direction. 
     As will be discussed further in the detailed description provided below, the various components may be made out of any suitable material. The material selected must, of course, provide sufficient strength and durability. In certain applications, weight may also be a factor used in selecting the materials used for construction of the locking device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a locking device, made in accordance with the present invention, in its open position; 
         FIG. 2  is perspective view of the locking device of  FIG. 1  with an elongate member positioned within the locking device and the locking device in its closed position; 
         FIG. 3  is a perspective view showing the outer frame of the locking device of  FIG. 1 ; 
         FIG. 4  is an exploded perspective view showing the components of the clamp of the locking device shown in  FIG. 1 ; 
         FIG. 5  is an exploded perspective view showing the components of the actuator of the locking device shown in  FIG. 1 ; 
         FIG. 6  is a side view of one of the side plates of the frame, one of the plates of the clamp and one of the plates of actuator to demonstrate the position of these plates when the locking device is open; 
         FIG. 7  shows the same components of the locking device as shown in  FIG. 6  but with the locking device in its closed position; 
         FIG. 8  is a perspective front view of an alternative embodiment facilitating automatic operation of the locking mechanism with the clamp open; 
         FIG. 9  is a view like  FIG. 8  with the clamp closed; and 
         FIG. 10  is a right side view with the right hand plate removed to show the automatic actuation features of the locking mechanism. 
     
    
    
     DETAILED DESCRIPTION 
     Referring first to  FIGS. 1-3 , the locking device  1  shown includes a frame  10  comprising a first side plate  12  having an elongate member receiving recess  14 . The frame  10  includes a second side plate  16  also having an elongate member receiving recess  18 . The frame  10  also includes a stop  20 , the function of which will be discussed below. Both side plate  12  and side plate  16  extend in parallel spaced relation to each other from a portion of an assembly (not shown). 
     Further details related to the construction of the outer frame are shown in  FIG. 3 . As shown, each side plate  12  and  16  of the frame has three holes  22 ,  24  and  26 . The function of these holes will become clearer from the description of the full assembly provided below. 
     The locking device  1  shown in  FIGS. 1-2  also includes a clamp  30 . The clamp  30  includes a plate  32 , including a retention surface  34 , and a plate  36  including a retention surface  38 . As shown in  FIG. 2 , when the clamp is in the closed position, the retention surfaces  34  and  38  engage an elongate member  100  to retain the elongate member within the elongate member receiving recesses  14  and  18  of the outer frame  10 . 
     Further details related to the construction of the clamp  30  are provided in  FIG. 4 . As shown, the clamp  30 , in addition to the plates  32  and  36  and the elongate member retention surfaces  34  and  38 , includes stop surfaces  35  and  39 . The plates  32  and  36  are held in spaced relation by a spacer  40 . Spacer  40  includes two outwardly extending rectangularly-shaped ears  41  which mate with rectangularly-shaped holes  42  in the plates  32  and  36  such that spacer  40  does not rotate or move with respect to plates  32  and  36 . A rotating link coupler  44  is also provided. Rotating link coupler  44  has a pair of opposed cylindrically-shaped ears  45  which mate cylindrically-shaped holes  46  in the plates  32  and  36  so that the rotating link coupler  44  is permitted to rotate with respect to plates  32  and  36  about a longitudinal axis passing through the center of the two ears  45 . Rotating link coupler  44  also has an orifice  48  extending through the spacer. Orifice  48  is surrounded by an engagement surface  49 . 
     Returning again to  FIGS. 1 and 2 , the locking device is also shown to include an actuator  60 . The actuator likewise includes a pair of actuator plates  62  and  64 . The construction of the actuator is better shown in  FIG. 5 . As shown in  FIG. 5 , the plates  62  and  64  of the actuator each include a stop surface  66 . The two plates are held in parallel spaced relation by a handle  68  and a spacer  70 . The handle  68  has opposed rectangularly-shaped ears  69  which mate with rectangularly-shaped holes  74  in the plates  62  and  64 . Likewise, spacer  70  has a pair of rectangularly-shaped ears  71  which mate with rectangularly-shaped holes  76  in the plates  62  and  64 . As such the handle  68  and the spacer  70  are held in a fixed position relative to the plates  62  and  64 . Actuator  60  also has a rotating link coupler  72 . Rotating link coupler  72  has a pair of cylindrically-shaped ears  73  which mate cylindrically-shaped holes  78  in the plates  62  and  64  such that the rotating link coupler  72  can rotate with respect to the plates  62  and  64  about a longitudinal axis extending through the centers of the ears  73 . Rotating link coupler  72  has an orifice  80  surrounded by an engagement surface  81 . 
     As shown in  FIG. 4 , each of the plates  32  and  36  of the clamp  30  include a cylindrical hole  33  passing through the plate. A pin  84  (shown in  FIG. 3 ) is passed through the holes  33  of the clamp. End portions of pin  84  are also mated with the holes  24  in side plates  12  and  16  of the frame  10  to pivotally mount the clamp  30  to the frame  10 . Similarly, each of plates  62  and  64  of the actuator  60  include a hole  61 . See  FIG. 5 . A pin  86  shown in  FIG. 3  passes through the holes  81  and mates the holes  22  of the plates  12  and  16  of the frame  10  to pivotally mount the actuator  60  to the frame  10 . 
     As shown in  FIGS. 1 and 2 , the assembly of the locking device  1  is complete by creating a link between the clamp  30  and actuator  60 . The drawings show this being done by passing the shaft  91  of bolt  90  through the orifice  80  of the rotating link coupler  72  of the actuator  60 , a compression spring  94 , the orifice  48  of the rotating link coupler  44  of the clamp  30  and then attaching a nut  92  to the bolt  90  to fix the bolt  90  in place. A cap  93  can also be attached to the exposed end of the shaft  91  of the bolt. When so assembled, the one end of the spring  94  engages the engagement surface  49  of rotating link coupler  44  of the clamp  30  and the other end of spring  94  engages the engagement surface  81  of rotating link coupler  72  of the actuator  60 . Those skilled in the art will recognize that different springs may be selected for use based on the desired or required spring force to be delivered by the spring. The assembly can also include a safety pin which passes through the holes  26  in the plates  12  and  16  of the frame  10  and engages safety pin engagement surfaces on the plates of the actuator as will be discussed in further detail below with references to  FIGS. 6 and 7 . 
       FIGS. 6 and 7  are illustrative of plate  16  of the frame  10  attached to a portion of an assembly (not shown) with the plate  36  of the clamp and plate  64  of the actuator pivotally attached to the plate  16  of the frame. Various spacers, pivot pins, the safety pin and the link comprising the rotating link couplers, the bolt and spring arrangement shown in  FIGS. 1 and 2  are not shown in  FIGS. 6 and 7  to better illustrate movement of the actuator plate  64  with respect to the clamp plate  36 . As shown in  FIG. 6 , the actuator plate  64  and the clamp plate  36  are both in their open position permitting an elongate member (such as  100  shown in  FIG. 2 ) to be inserted into or removed from the elongate member receiving recess  18  of the frame  10 . Upon rotation of the actuator plate  64  in the counter-clockwise direction, the link formed by rotating link couplers  44  and  72 , bolt  90 , spring  94  and nut  92  causes the clamp plate  36  to also rotate in a counter-clockwise direction such that the elongate member retention surface  38  covers the opening to the elongate member receiving recess  18  of plate  16 . 
       FIG. 7  shows how rotation of the actuator plate  64  and clamp plate  36  will continue until the actuator plate  64  engages the stop  20 . In this position, the stop surface  66  of actuator plate  64 , clamp plate  36  and link comprising rotating link couplers  44  and  72 , bolt  90 , spring  94  and nut  92  are over center such that movement of the actuator plate  64  and clamp plate  36  in the clockwise direction is resisted. More specifically, forces which might cause the clamp plate  36  to open, given the tolerances of the design, instead cause the stop surface  39  of the clamp plate  36  to engage the stop surface  66  of the actuator plate  64  to resist such forces and prevent the clamp from opening. Such movement is also resisted by the force of spring  94 . To ensure that no such counterclockwise motion occurs, a pin (such as pin  99  shown in  FIGS. 1 and 2 ) can be inserted through hole  26  in plate  16  so that the shaft of the pin engages a first safety pin engagement surface  110  on actuator plate  64  to prevent such rotation and securely locking the clamp plate  36  in the position shown in  FIG. 7 . Likewise, to hold the clamp plate  36  in the open position shown in  FIG. 6 , such a pin can be inserted through hole  26  such that the shaft engages second safety pin engagement surface  112 . 
     As the actuator plate  64  moves in the clockwise direction from the position shown in  FIG. 7  to the position shown in  FIG. 6 , the link formed by rotating link couplers  44  and  72 , bolt  90 , spring  94  and nut  92  shown in  FIGS. 1 and 2  causes the clamp plate  36  to follow the actuator plate  64  and also rotate in the clockwise direction until the stop surface  39  of clamp plate  36  engages stop  20 . Stop  20  prevents over rotation of the entire assembly. 
     From the foregoing those skilled in the art will appreciate that locking devices of the present invention may be employed in a variety of situations to provide firm and secure locking of an elongate member to an assembly. A secure connection is provided and ensured not only by the over center position of the stop surfaces when the clamp plates  32  and  36  are in the closed position but also by the additional provision of a safety pin  99  which prevents any rotation of the actuator and clamp plates until the pin  99  is removed. Further, the force applied by the compression spring  94  provides an additional margin of safety. 
     One skilled in the art will also recognize from the foregoing that various modifications can be made without deviating from the invention. First, rather than using a pair of plates to form the actuator  60  and a pair of plates to form the clamp  30 , a single plate actuator and a single plate clamp could be used. Likewise, more than two plates could be used to form the actuator  60  and clamp  30 . Springs which apply differing spring forces may also be used. 
     Various materials can also effectively be used in forming a locking mechanism in accordance with the present invention. Steel, aluminum, iron and other metals could be used. Various high strength polymers such as nylon or the like could also be employed. Additional features may also be provided without departing from the invention. For example, the surfaces of the elongate member receiving recesses  14  and  18  of the frame  10  and the retention surfaces  34  and  38  of the clamp  30  may be padded to prevent marring of the finish of any elongate member  100  attached to an assembly using the locking device  1  of the present invention. The receiving surfaces and retention surfaces could also be provided with a series of narrow ridges to provide a better grip on the elongate member  100 . The shapes and sizes of the various components may also be modified as appropriate. 
     Alternative Embodiment 
     The previously described embodiments contemplate that the locking device for coupling an elongate member to an assembly is to be manually actuated by rotating the actuator  60  after the elongate member is positioned within the elongate member receiving recess  14 - 18  using the handle  68 . The embodiment of  FIGS. 8-10  teaches a way of actuating the locking device onto an elongate member from a more remote location. 
     Referring first to  FIG. 8 , the locking device  102  includes a frame  110  comprising a first side plate  112  having an elongate member receiving recess  114 . The frame  110  includes a second side plate  116 , also having an elongate member receiving recess  118 . The frame  110  also includes a first stop  120  and a second stop  121 , the functions of which will be discussed below. Both side plate  112  and side plate  116  extend in parallel, spaced relation to each other and are adapted to be connected to an assembly (not shown). With continued reference to  FIG. 8 , each side plate  112  and  116  of the frame  110  has three holes  122 ,  124  and  126  formed through the thickness dimension of the side plates. 
     The locking device  102 , like the earlier embodiments, includes a clamp  130  having a first plate  132  that includes a retention surface  134 , and a second plate  136  that includes a retention surface  138 . As shown in  FIG. 9 , when the clamp is in its closed position, the retention surfaces  134  and  138  are made to engage an elongate member such as a cylinder rod as at  100  in  FIG. 2  so as to retain the elongate member within the elongate member receiving recesses  114  and  118  of the outer frame  110 . 
     Further details related to the construction of the clamp  130  can be seen in  FIG. 10 . As shown there, the clamp  130 , in addition to the plates  132  and  136  and the elongate member retention surfaces  134  and  138 , includes stop surfaces, as at  135  on the plate  132 . The plates  132  and  136  are held in parallel, spaced relation by a spacer member  140 . Extending between the clamp plates  132  and  136  is a rotatable coupler  141 . Likewise, extending between the actuator plates  162  and  164  of the actuator  160  is a rotatable coupler  143  and spacer  172 . The rotatable coupler  141  and  143  each comprise a hub having an aperture extending through it for receiving the shaft  191  of a bolt therethrough. As seen in  FIG. 10 , the shaft  191  is surrounded by a helical compression spring  194  and a nut  196  along with the bolt head  195  secures the bolt in place. 
     Inserted through the hole  124  and through an aligned hole in the second side plate  116  (not shown) is a pin  198  forming an axle about which the clamp plates  132  and  136  can rotate relative to the first and second side plates  112  and  116 . 
     In a similar fashion, a pin  200  journals the actuator assembly  160  relative to the first and second side plates  112  and  116 . 
     In the embodiment of  FIGS. 8-10 , the first and second side plates  112  and  116  each include an upwardly extending elongate arm  202  and  204  and secured between the two arms by a through bolt  206  is a linear actuator  208  which, in practice, may be either a hydraulic or an air cylinder or alternatively, an electrical solenoid adapted to be operated from a remote position, such as by an operator in the cab of a work vehicle. As best seen in  FIG. 10 , the piston rod  210  of the linear actuator  208  passes through a rotatable coupler that is journaled for rotation in the actuator plates  162  and  164  at a location that is laterally offset from the pivot pin  200  of the actuator thereby providing a lever arm for the linear actuator  208  to work against. Adjustment is possible by turning nuts  192  and  193 . 
     As can be seen in  FIGS. 8 and 10 , passing through the stop  120  and extending to the rear of the elongate member receiving recesses  114  and  118  is a sensor  216  that is positionable relative to the elongate member receiving recesses  114  and  118  by adjustment nuts  218 . The sensor may be of any suitable type capable of detecting when an elongate member is resident within the elongate member receiving recesses  114  and  118 . Without limitation, the sensor may simply be an electromechanical switch, a magnetic sensor such as a Hall device or other type of proximity sensor known in the art. 
     In operation, the assembly to which the locking device  102  is attached may be moved so as to be brought into proximity to an elongate member. When the sensor  216  detects that an elongate member is resident within the receiving recesses  114  and  118 , the linear actuator  208  may be operated automatically (or manually) from a remote location to extend the piston rod  210  and in doing so, rotation is imparted in a clockwise direction, as viewed in  FIG. 10 , to the actuator assembly  160  which then pivots about the pin  200 , forcing the clamping plates  132  and  136  to rotate in a counterclockwise direction about the pin  198  and thereby capturing the elongate member within the recesses  114  and  118  of the first and second side plates  112  and  116 . Those skilled in the art will appreciate that, initially, as the piston rod  210  is made to extend, it works against the compression spring  194  until an over-center position is reached, at which point the spring acts to maintain the retention surfaces  134  and  138  of the clamp firmly against the captured elongate member. Further rotation of the actuator is prevented by stop  121  after the over-center condition is reached. 
     It will be appreciated that unhooking or unfastening the elongate member from the locking mechanism will be achieved by again remotely operating the linear actuator  208  to withdraw its piston rod  210  back into its cylinder which has the effect of rotating the actuator  160  in a counterclockwise direction causing the clamp  130  to rotate in the clockwise direction opening the locking device. 
     The detailed description is not intended to be limiting, but rather to explain attributes of the invention and how they can be implemented. The invention is only limited by the claims recited below.