Abstract:
A wheel chock assembly is provided having a base member extending axially from a top end to a bottom end, first and second support members whose upper ends are pivotally and slidably engaged with respect to the base member, first and second wheel chocks mounted with respect to the lower ends of the support members, and an adjustment mechanism mounted to the base member. The adjustment mechanism is operatively engaged to the support members to achieve axial movement of their upper ends with respect to the base member to extend and retract them within a range that permits the assembly to grip the wheel of a cart between the wheel chocks. Preferably, the adjustment mechanism is a cord secured to the main member of the base member such that pulling the cord upward draws the main member into the handle of the base member, extending the support members outward, while releasing the cord withdraws the main member from the handle, retracting the support members inward. A method is also provided for securing the wheel of a cart.

Description:
FIELD OF THE INVENTION 
   This invention is related generally to wheel chocks and, more particularly, to a portable wheel chock assembly for securing a wheel of a cart. 
   BACKGROUND OF THE INVENTION 
   Wheel chock assemblies are used to secure a wheel in place for a limited amount of time. Such assemblies in the prior art typically consist of flanges of a particular shape that interact with the wheel to keep it in a certain desired position. Examples of these prior art wheel chock assemblies are disclosed in the following United States patents: Pat. No. 3,120,292 (Rambat), Pat. No. 4,854,790 (Andre) and Pat. No. 6,378,956 (Van De Walker). 
   These wheel chock assemblies of the prior art have, however, a number of problems and shortcomings. They are often bulky, thereby making them difficult to transport and manage. Given the nature of the use of a wheel chock assembly, it has to be transported to the location where it is needed. While it would be desirable to store the wheel chock assembly in the trunk of a vehicle or other storage space, most wheel chock assemblies in the prior art are hard to manage since they usually require a large amount of storage space given their large size. This storage space could be allocated to other and better uses if the assembly was smaller. A wheel chock assembly that is easily collapsible would therefore be greatly appreciated not only for being conveniently portable but also for its advantages when stored between uses. 
   In addition, utilization of most wheel chock assemblies can be difficult and time consuming. There has therefore long been a need for a wheel chock assembly that is quick and easy to operate when the need for such a device arises. In particular, there have been many occasions where a shopper will be attempting to empty the contents of his or her shopping cart into the trunk of their vehicle when the wheeled cart begins to roll away from both the shopper and the vehicle. Not only does this make unloading the contents of the cart difficult, but oftentimes the cart rolls away unnoticed, colliding with other objects, including other vehicles. Having available a wheel chock assembly that is both simple to store and easy to use in such situations would be a great convenience to such individuals. 
   This invention meets these needs and overcomes other problems and shortcomings in the prior art with an apparatus that is simple and inexpensive to construct, not at all complicated to maintain, and also highly reliable to use. 
   SUMMARY OF THE INVENTION 
   This invention is for a wheel chock assembly that includes a base member extending axially from a top end to a bottom end, first and second support members where the upper ends of the support members are pivotally and slidably engaged with respect to the base member, first and second wheel chocks that are mounted with respect to the lower ends of the support members, and an adjustment mechanism mounted to the base member. The adjustment mechanism is operatively engaged to the support members to achieve axial movement of the upper ends with respect to the base member so that the support members can be extended and retracted within a range that permits its the assembly to obtain the desired spacing between the wheel chocks for gripping the wheel of a cart. 
   In certain preferred embodiments, the adjustment mechanism is a cord and the base member has a main member and a handle. The main member is sized to fit into the bottom opening of the handle. Most preferred is where both the main member and the handle are cylindrical in shape and the main member has an outside diameter less than the inside diameter of the handle. Highly desirable is where the handle has at least two sections telescopically connected to allow it to reversibly expand and collapse. 
   These preferred embodiments find the cord secured to the main member such that upward movement of the cord draws the main member within the handle which extends the support members outward and moving the cord downward withdraws the main member from the handle to retract the support members inward. More desirable is where the cord has proximal and distal ends, the proximal end extending outward from the top end of the handle and the distal end being attached to an upper portion of the main member. The terms “upward” and “downward” provide relative positioning with respect to a vertical dimension and are used in this application for ease in discussing the embodiments of the present invention although the wheel chock assembly can be used in a variety of orientations. Likewise, the terms “proximal” and “distal” also provide relative positioning with respect to the user of the wheel chock assembly and are similarly used in this application for ease in discussing the embodiments of the present invention. 
   Some desirable embodiments have the base member further including a plunger and compression spring. The plunger has a bore passing through it that is large enough to receive the cord. In these embodiments, the handle has a passageway that extends from the bottom opening to the top end and an aperture communicating with the passageway. The aperture is positioned radial or orthogonal to the axis of the passageway and is sized to receive the plunger. The spring is also radial to the passageway, abutting and in alignment with the plunger so that the plunger is biased by the spring to move outward away from the passageway. In addition, the cord extends from one end of the passageway to the other by way of the bore of the plunger. Therefore, pushing the plunger inward aligns the bore axially with the passageway to permit free axial movement of the cord within the passageway. Releasing the plunger, on the other hand, allows the plunger to retract outward from the passageway which crimps the cord within the aperture and prevents any axial movement of the cord since the aperture is sized so that it can snugly receive both the plunger and the cord. 
   In other desirable embodiments, the upper ends of the support members are pivotally secured to a slide-bar. The slide-bar extends through the lower end of the handle between the upper ends of the support members. In these embodiments, the main member has a slot along its upper portion that includes two longitudinal notches in radial alignment. Each notch is sized to slidably receive the slide-bar. Axial movement of the main member in one direction with respect to the handle, typically upward or downward, results in axial movement of the slide-bar within the slot in the opposite direction. The axial movement of the slide-bar is limited, however, by the length of the slot. 
   Most preferred is where the wheel chock assembly also includes first and second inner links. The inside ends of the links are pivotally secured adjacent to the lower portion of the main member. The outside ends of the links are pivotally connected at points proximal to the respective lower end of the first and second support members. In these embodiments, axial movement of the slide-bar in a downward direction (i.e., towards the distal end of the slot) forces the inner links outward from the main member, openly extending the support members. Axial movement of the slide-bar in the opposite or upward direction draws the inner links inward towards the main member, thereby collapsibly retracting the support members. Highly preferred embodiments find the inside ends of the inner links are joined by a torsion spring to cause the inner links to be drawn inward towards the main member by the spring. 
   In other embodiments that are desirable, each wheel chock is pivotally mounted to a respective support member so that the wheel chock is free to move between open and closed positions. More desirable is where the wheel chocks are cylindrical in shape. 
   Another aspect of this invention is directed to a method for securing the wheel of a cart. The method includes the steps of providing an assembly that is expandable to form a wheel-receiving space defined by wheel chocks; expanding the assembly; and gripping the wheel between the wheel chocks. The assembly has a base member, first and second support members pivotally and slidably engaged to the base member, first and second wheel chocks mounted to the lower ends of the first and second support members, and an adjustment mechanism mounted with respect to the base member that is operatively engaged to the support members to axially move them with respect to the base member 
   A desired embodiment includes the step of adjusting the assembly spacing by extending and retracting the support members between certain limits to firmly grip the wheel between the wheel chocks. In certain cases, the step is added of unloading the contents of the cart with the wheel chock assembly firmly gripping the wheel. 
   Most preferred is where the adjustment mechanism is a cord and the adjusting step includes placing the wheel between the wheel chocks when the assembly is in the expanded position and lowering the cord to cause the support members to pivot inward to create a pinching effect on the wheel between the wheel chocks, thereby securely gripping the wheel between the wheel chocks. Highly desirable is where the wheel which is secured with the assembly is on a shopping cart. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded perspective view of a preferred wheel chock assembly in accordance with this invention. 
       FIG. 2  is an exploded view of the cap, plunger and compression pin of the assembly in  FIG. 1 . 
       FIG. 3  is a front perspective view of the assembly in  FIG. 1  in the open position. 
       FIG. 4  is a back perspective view of the assembly in  FIG. 1  in the closed position. 
       FIG. 5  is a back view of the assembly in  FIG. 1  in the open position gripping a wheel. 
       FIG. 6  is a side view of the assembly in  FIG. 5 . 
       FIG. 7  is a front view of the assembly in  FIG. 5 . 
       FIG. 8  is a fragmentary detailed view of the assembly in  FIG. 1  illustrating from a back perspective the support members and the wheel chocks in the open position gripping a wheel. 
       FIG. 9  is a fragmentary detailed view of the assembly in  FIG. 1  illustrating from a front perspective the support members and the wheel chocks in the open position gripping a wheel. 
       FIG. 10  is a side perspective view of a shopping cart illustrating the wheel chocks of the assembly in  FIG. 1  in the open position gripping a wheel 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1  illustrates a wheel chock assembly  10  in accordance with this invention. As shown in  FIGS. 1 and 3 , the wheel chock assembly  10  is comprised of base member  12 , first and second support members  14 , 16 , first and second wheel chocks  56 , 58 , and adjustment mechanism  98 . Adjustment mechanism  98  in the preferred embodiment shown in FIGS.  1  and  3 - 7  is cord  40 . Base member includes handle  24  and main member  22 . 
   Main member  22  fits securely within handle  24  as shown in  FIGS. 3 ,  5  and  10 . Main member  22  is cylindrical having outside diameter  23  that is less than the inside diameter  25  of cylindrical handle  24 , thereby allowing main member  22  to be slidably received in bottom opening  28  of handle  24  as shown in  FIG. 1 . Main member  22  is oriented in a co-axial manner with handle  24  along axis  92  as illustrated in  FIGS. 1 and 3 . 
   Upper ends  18  of first and second support members  14 , 16  are pivotably connected to handle  24  by slide-bar  48 . As illustrated in  FIG. 1 , slide-bar  48  first passes through hole  27  in upper end  18  of second support member  16 . Next, slide-bar  48  passes through the first of two aligned apertures  29  (only one being shown) in handle  24 . Since handle  24  is positioned over the proximal or upper portion  30  of main member  22 , slide-bar  48  is free to pass through slot  46  in main member  22  and then through the remaining aperture  29 . Finally, slide-bar  48  proceeds through hole  27  in upper end  18  of first support member  14  before being capped to secure slide-bar  48  with attached support members  14 . 16  to handle  24 . 
   Slot  46 , as seen in  FIG. 1 , has two identical notches  114  (only one being shown) in radial alignment along upper portion  30  of main member  22 . Notches  114  are sized to slidably receive slide-bar  48 . One skilled in the art will recognize that slide-bar  48  is free to axially move within slot  46  within the limits of notches  114 . Top stop  100  and bottom stop  102  at both ends of notches  114  therefore define axial movement of slide-bar  48  within slot  46 . 
   Cord  40  passes from main member  22  into handle  24  through hole  31  in main-member cap  42  securely mounted at the proximal end of main member  22 . Cord  40  is secured to main member  22  at upper portion  30  by cord knot  44  distal to main-member cap  42  and sized not to pass through hole  31 . Handle  24  has bottom opening  28  which allows cord  40  to pass into handle  24  and through handle  24  to cap  38  that frictionally fits upon top end  33  of handle  24 . 
   Plunger  34  and compression spring  36  are positioned within cap  38 .  FIG. 2  illustrates that cap  38  includes recess  85  and aperture  88 . Compression spring  36  is seated within recess  85  which extends radially or orthogonal to passageway  90  of handle  24 . Plunger  34  abuts compression spring  36  and is supported laterally within cap  38  by aperture  88 . Aperture  88  communicates with the exterior of handle  24  and is positioned opposite to recess  85 , also extending orthogonal to passageway  90 . Aperture  88  allows plunger  34  to have its distal portion  87  extend into passageway  90  while its proximal portion  89  protrudes outward from handle  24 . One skilled in the art will recognize that plunger  34  is biased to move outward through aperture  88  by compression spring  36  and that pushing plunger  34  inward to expose more of distal portion  87  to passageway  90  requires compression of spring  36 . 
   Distal portion  87  of plunger  34  includes bore  86 . Bore  86  extends linearly through distal portion  87  and is cylindrical in shape, having a diameter large enough to slidably receive cord  40 . Cord  40  extends through passageway  90  which runs through the center of handle  24  from bottom opening  28  through cap  38  at top end  33 . In cap  38 , passageway  90  passes axially from bottom to top. Cord  40  enters through the bottom of passageway  90  and proceeds through bore  86  before exiting cap  38  and extending outward from handle  24  at top opening  91 . 
   When plunger  34  is pushed inward, plunger  34  aligns bore  86  with passageway  90 , allowing cord  40  to move freely within passageway  90 . When plunger  34  is released, plunger  34  moves outward by action of compression spring  36  to crimp cord  40  outside of bore  86  at both of its ends between plunger  34  and the inner walls of aperture  88 . One skilled in the art will recognize that once cord  40  is crimped by plunger  34 , cord  40  is no longer able to move axially in either direction, maintaining main member  22  in its position with respect to handle  24 . Aperture  88  is sized so that it can receive plunger  34  and cord  40  but still securely pinch cord  40  when drawn within it by plunger  34 . 
   Handle  24  consists of three telescoping sections, first extension  116 , second extension  118  and third extension  120  as shown in  FIGS. 3-7  and  10 . This allows handle  24  to extend and collapse axially. The telescoping nature of handle  24  allows users of wheel chock assembly  10  to adjust handle  24  for ease of use. 
   As illustrated in  FIG. 1 , support members  14 , 16  are pivotally connected to main member  22  by inner links  50 , 51 . Inside end  52  of each inner link  50 , 51  is pivotably secured to bottom or distal end  32  of main member  22  by assembly pin fastener  72 . Assembly pin fastener  72  passes through hole  106  on inside end  52  of first inner link  50  before extending through torsion spring  70 . Assembly pin fastener  72  finally proceeds through apertures  108  in registry at bottom end  32  (only one being shown) before finally passing through inside end  52  of second inner link  51 . Inside pin  82  secures the end of assembly pin fastener  72 . 
   Outside ends  54  of inner links  50 , 51  are pivotally secured at points proximal to lower end  20  of first and second support members  14 , 16 . Outside ends  54  are connected to support members  14 , 16  by pins  76 , cylindrical nut  78  and end piece  80  as shown in  FIG. 1 . Each pin  76  passes through support hole  110  in support member  14 , 16 , through cylindrical nut  78 , and then through inner link  50 . 51 . End piece  80  caps pin  76  to secure outside end  54  of each inner link  50 , 51  to its respective support member  14 , 16 . 
   As illustrated in  FIGS. 1 ,  3 - 6  and  8 - 9 , first and second wheel chocks  56 , 58  are pivotably secured to lower ends  20  of first and second support members  14 , 16 . Attached end  68  of each wheel chock  56 , 58  is pivotably connected to cylindrical protrusion  60 . Cylindrical protrusion  60  extends outward from lower end  20  of each support member  14 , 16  and is received into pivot slot  61  on attached end  68 . Pivot pin  64  is then pushed into pivot holes  62  in linear alignment extending through both attached end  68  and protrusion  60 , thereby pivotably securing first and second wheel chocks  56 , 58  to first and second support members  14 , 16 . 
   Attached end  68  of each wheel chock  56 , 58  can be pivoted so that free end  66  is positioned adjacent to the respective support member  14 , 16  to which wheel chock  56 , 58  is attached as shown in  FIG. 4 . Pivotability of wheel chocks  56 , 58  may be optional in that wheel chocks  56 , 58  can always remain in an open position as seen in  FIGS. 1 ,  3 ,  5 - 10 . 
   Upper movement of cord  40  draws main member  22  into handle  24 , causing slide-bar  48  positioned at the bottom of handle  24  to pass downward within slot  46 . When slide-bar  48  is moved in a downward direction, inner links  50 , 51  are forced outward from main member  22  as shown in  FIGS. 3 ,  5 ,  8 ,  9 - 10 . This movement causes first and second support members  14 , 16  to open in an outward direction, thereby creating a wide wheel receiving space  104  (defined as the space between first and second wheel chocks  56 , 58 ) as illustrated in  FIG. 3 . 
   Downward movement of cord  40 , on the other hand, allows main member  22  to drop or withdraw from handle  24 , causing handle  24  to thereby move upward with respect to main member  22 . This relative movement by handle  24  results in slide-bar  48  to rise upward within slot  46 . When slide-bar  48  is moved in an upward direction, inner links  50 , 51  are pulled inward towards main member  22 . Support members  14 , 16  with their attached wheel chocks  56 ,  58  are in turn drawn inward, reducing or, when collapsed, eliminating wheel receiving space  104  as seen in  FIG. 4 . This narrowing of wheel receiving space  104  permits wheel  84  of shopping cart  112  to be held firmly between wheel chocks  56 , 58  as shown in  FIGS. 5-10 . 
   One skilled in the art will therefore readily see that axial movement of main member  22  in a first direction with respect to handle  24  results in axial movement of slide-bar  48  within slot  46  in an opposite second direction. Slide-bar  48  will thus always move in a direction opposite to that of the movement of main member  22 . 
   First and second support members  14 , 16  are preferably flat bars chosen to have a desired length when extended outward from base member  12 . These bars also have sufficient width to attach to first and second wheel chocks  56 , 58  but a narrow depth so that when first and second support members  14 , 16  are retracted, they are able to lie flat or nest against the exterior of main member  22  as illustrated in  FIG. 4 . 
   Among its many uses, wheel chock assembly  10  can secure wheel  84  on shopping cart  112  in a parking lot as shown in  FIG. 10 . Wheel chock assembly  10  is easily stored in a vehicle trunk. Once an individual is done shopping, wheel chock assembly  10  is removed from the vehicle trunk and expanded outward as illustrated in  FIG. 3 . Wheel chock assembly  10  is expanded by pushing in on plunger  34  to pull upward on cord  40 . This draws main member  22  within handle  24 , thereby extending first and second support members  14 , 16  outward. Handle  24  can then be expanded telescopically as shown in  FIG. 3  to a length that is comfortable to the individual. The user then moves first and second wheel chocks  56 ,  58  into their open position, i.e., where free end  66  of each wheel chock  56 , 58  is extended outward as illustrated in  FIGS. 1 ,  3 ,  5 - 10  and is not adjacent to or nesting against first and second support members  14 , 16 . 
   As shown in  FIGS. 5-10 , the individual then places wheel  84  in the space between first and second wheel chocks  56 , 58 . Cord  40  is now released in a downward direction, causing main member  22  to withdraw from handle  24  and retracting support members  14 , 16  to have wheel chocks  56 , 58  firmly grip wheel  84  as seen in  FIGS. 5-10 . At this point, the user releases the pressure that had been placed upon plunger  34 , allowing plunger  34  to move outward from handle  24 , crimping cord  40  within aperture  88  so that support members  14 , 16  and thereby wheel chocks  56 , 58  are held in this desired position. 
   Once wheel  84  is gripped as illustrated in  FIG. 10 , the contents of cart  112  are unloaded. After the contents of cart  112  are unloaded, the user pushes plunger  34  inward again to cause bore  86  to return to an axial alignment with passageway  90 , thereby permitting movement of cord  40  within passageway  90 . The individual then allows cord  40  to proceed in a downward direction, thereby having main member  22  drop from handle  24 . This retracts first and second support members  14 , 16  until they are nesting against main member  22  as shown in  FIG. 4 . Furthermore, this results in inner links  50  being positioned so that outside ends  54  are angled upward towards handle  24 . First and second wheel chocks  56 , 58  can then be moved by the user into their closed position so that free ends  66  rest adjacent to first and second support members  14 . 16 . Wheel chock assembly  10  is then stored, preferably in the trunk of the vehicle, until its next use. 
   A wide variety of materials are available for the various parts discussed and illustrated herein. Although the invention have been shown and described in conjunction with specific embodiments thereof, it is to be understood that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.