Abstract:
The present invention relates to a drive pin having a shank and a head asymmetrically disposed relatively to said shank. It also relates to a wall anchor assembly comprising a wall anchor adapted to be inserted in a wall for firmly maintaining the wall anchor assembly thereon; a passageway along the wall anchor; and a drive pin adapted to be inserted in the passageway and having a head providing, upon rotating the drive pin inserted in the passageway, a variable distance between the periphery of the head and an object mounted proximate thereto.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority of U.S. provisional patent application 60/503,494, filed Sep. 17, 2003, the specification of which is hereby incorporated by reference. 

   BACKGROUND OF THE INVENTION 
   1. ) Field of the Invention 
   The present invention relates to a drive pin having a head asymmetrically mounted on its shank and, more particularly, to an asymmetric drive pin used in combination with a wall anchor. 
   2. ) Description of the Prior Art 
   Back clip assemblies are usually used for mounting shelves on walls and include a body with a wall anchor extending therefrom and a rod engaging hook formed in it. Several back clip models are available on the market and some of them comprise a wall anchor with laterally expandable fingers to increase the anchoring strength. These fingers are expanded against the back side of a wall when a drive pin is inserted through the wall anchor as shown in U.S. Pat. Nos. 4,264,047; 4,669,936; and 4,722,648. 
   Shelves for wall mounting typically comprise back and front rods extending the length of the shelf, parallel to each other, and regularly spaced parallel cross rods, perpendicular to the back and front rods. The cross rods have a rear and a front ends. The rear and frond ends are respectively mounted on the upper side of the back and front rods. The cross rods are sufficiently close to each other to support articles, even small ones, on them. 
   For mounting a shelf on a wall, at least two back clips are mounted on the wall, at the same height with respect to the ground. The back rod of the shelf is inserted in the rod engaging hooks of the back clips. 
   Two major problems occur with this type of fastening device. On one hand, the back rod is often released from the rod engaging hook due to a pressure applied on the shelf. On the other hand, the drive pin is sometimes released from the wall anchor due to a pressure applied on the expandable fingers. To overcome these problems, U.S. Pat. No. 4,669,936 discloses a back clip with a stop member, having a recess in it, and pivotally mounted on the upper part of the clip. Once the back rod of the shelf is inserted in the hook, the stop member is pivoted downwardly and the head of the drive pin is covered by the stop member, inside its recess portion. In this position, the stop member blocks the release of the shelf back rod from the hook and, at the same time, covers the head of the drive pin. However, interference frequently occurs between the stop member and the cross rods since the back clips are often installed without prior consideration for the cross rod location, and the stop member is significantly wide. When interference occurs, the stop member then cannot be pivoted downwardly. U.S. Pat. No. 4,722,648 solved a part of this problem by providing recesses and notches on opposite sides of the stop member. These notches and recesses allow the stop member to clear some cross rods that otherwise would interfere with the stop member. However, this solution requires more steps to be performed by the installer for mounting a shelf and cannot be applied if some cross rods are thicker than others. 
   SUMMARY OF THE INVENTION 
   It is a object of the present invention to provide a new wall anchor assembly, having a drive pin, which addresses the above concerns and which can be used in a back clip assembly. 
   One aspect of the invention provides a drive pin comprising a shank having a trailing end and a leading end; and a head asymmetrically disposed relative to the trailing end of the shank. 
   Another aspect of the invention provides a wall anchor assembly comprising: a body section having a back face for abutment against a wall and a front face, a wall anchor extending from the back face, a passageway defined along the wall anchor and through the body, the wall anchor being adapted to be inserted in the wall for firmly maintaining said wall anchor assembly thereon, and a support member extending from the front face and transversally spaced from the passageway; and a drive pin adapted to be inserted in said passageway and having a head providing, upon rotating said drive pin in said passageway, a variable distance between the periphery of said head and the support member. 
   Another aspect of the invention provides a back clip in combination with a drive pin, the back clip comprising: a wall anchor for mounting the back clip to a wall, the wall anchor having a passageway adapted to receive the drive pin therein and a support member for mounting an object to the back clip; and the drive pin having a head providing, upon rotating the drive pin in the passageway, a variable free spacing between the periphery of the head and the support member. 
   Another aspect of the invention provides a drive pin adapted to be inserted into a wall anchor. The drive pin and the wall anchor comprise at least one groove and at least one protruding member, the at least one groove being adapted to receive at least one protruding member in a mating engagement for firmly maintaining the drive pin in the wall anchor. 
   A further aspect of the invention provides a wall anchor assembly comprising: an insert defining a passageway therealong and having at least one finger member pivotally mounted; and a drive pin being adapted to provide an outward pivotal movement of the at least one finger member when inserted in the passageway. The insert and the drive bin have at least one female member and at least one male member engaging one another when the drive pin is inserted in the passageway to firmly maintain the drive pin therein. 
   Another aspect of the invention provides a wall anchor adapted to be inserted into a wall in combination with a drive pin having a shank. The wall anchor comprises a passageway therealong for inserting the drive pin therein; and at least one finger member pivoting outwardly when the drive pin is inserted in the passageway. The wall anchor and the drive pin include at least one groove and at least one protruding member engaging one another when the drive pin is inserted in the passageway to firmly maintain the drive pin therein. 
   Another aspect of the invention provides a shelf support assembly comprising: a back clip having a body with a back face and a front face, an upper portion and a lower portion, a wall anchor extending from the back face, in the upper portion, and a shelf-receiving hook extending from the front face, in the lower portion, and a passageway traversing the body and the wall anchor; and a drive pin having a shank for insertion into the passageway, and a head having an off centered portion relative to the shank, the drive pin being rotatable in the passageway for rotating the off-centered portion from a shelf-engagement orientation, away from the hook, to a shelf-locking orientation, towards the hook, when a portion of the shelf is engaged in the hook. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which: 
       FIG. 1  is a perspective view of a drive pin in accordance with an embodiment of the present invention; 
       FIG. 2  is a perspective view of a back clip assembly in accordance with an embodiment of the present invention, wherein the drive pin is partially inserted in the passageway; 
       FIG. 3  is a side view of the back clip assembly of the embodiment shown on  FIG. 2 , wherein the drive pin is partially inserted in the passageway; 
       FIG. 4  is a perspective view of the back clip assembly of the embodiment shown on  FIGS. 2 and 3 , wherein the shank of the drive pin is completely inserted; 
       FIG. 5  is a side view of the back clip assembly of the embodiment shown on  FIGS. 2 and 4 , wherein the shank of the drive pin is completely inserted; 
       FIG. 6  is a front view of the back clip assembly of the embodiment shown on  FIGS. 2-5 , wherein the head of the drive pin is in a first position; 
       FIG. 7  is a front view of the back clip assembly of the embodiment shown on  FIGS. 2-5 , wherein the head of the drive pin is in a second position; 
       FIG. 8  is a front view of the back clip assembly of the embodiment shown on  FIGS. 2-5 , wherein the head of the drive pin is in a third position; 
       FIG. 9  is a perspective view of the back clip assembly of the embodiment shown on  FIGS. 2-5 , wherein a cross rod of a shelf abuts the back clip assembly and the head of the drive pin is in the first position; and 
       FIG. 10  is a perspective view of the back clip assembly of the embodiment shown on  FIGS. 2-5 , wherein a cross rod of a shelf abuts the back clip assembly and the head of the drive pin is in the third position. 
   

   It will be noted that throughout the appended drawings, like features are identified by like reference numerals. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , it will be seen that an asymmetric drive pin  20  according to the invention has a shank  22 , with a trailing end  24  and a leading end  26 , and a head  28  with an inner face  30  and an outer face  32  opposed to the inner face  30 . The inner face  30  of the head  28  is asymmetrically mounted to the trailing end  24  of the shank  22 . As shown on  FIG. 1 , the periphery of the head  28  has a semi-circular shape with a straight edge  34  and a semi-circular edge  36 . The straight edge  34  is mounted contiguous to the shank  22 . Even if a semi-circular shaped head  28  is shown in the embodiment of  FIG. 1 , one skilled in the art will appreciate that the head  28  can have any predetermined shape provided it is not symmetrically mounted to the shank  22  in all directions. For example, a circular shaped head (not shown) can be asymmetrically mounted to the shank. 
   The head  28  includes a slot  38  along its outer face  32  and above the shank  22  for inserting a screw driver (not shown) or any other object having a rigid flat narrow surface to facilitate the rotation of the drive pin  20 . The slot  38  divides the head  28  into two portions which can have a similar surface area as shown in  FIG. 1  or different surface areas as shown in  FIG. 2 . One skilled the art will appreciate that the slot  38  is not essential and that other means could be provided for allowing the drive pin  20  to be rotated. 
   A circular flange  40  is fixedly mounted around the shank  22 , below the head  28 . The flange  40  prevents the insertion of the drive pin  20  into a passageway, a hole or a wall since its diameter is wider than the one of the drive pin  20 . The flange  40  is connected to the head  28  through three side connecting members  42  provided at a regular spacing around the semi-circular edge  36  of the head  28 . The side connecting members  42  reinforce the connection between the head  28  and the flange  40 , especially during the drive pin insertion and rotation. One skilled the art will appreciate that the drive pin  20  can be provided without the flange  40  and the connecting members  42 . The insertion of the drive pin  20  can also be stopped by the head  28 . 
   The leading end  26  of the shank  22  is wedge-shaped, creating two wedge-shaped faces  46 . The wedge-shaped faces  46  facilitate the insertion of drive pin  20  in a back clip  48  ( FIG. 2 ) or in any other object or surface such as a wall by reducing the stresses applied thereon. The leading end  26  can also be provided with any other shape such as a conical, a round, or a rectangular shape. 
   A groove  50 , or a female member, surrounds the shank  22 , proximate to the leading end  26 . When the drive pin  20  is inserted into an anchoring device such as a wall anchor  52  ( FIG. 2 ) having fingers  54  ( FIG. 2 ), the groove  50  maintains drive pin  20  in the anchoring device, even when pressure is applied, as it will be explained more in details later. 
   The drive pin  20  is preferably cast or extruded in one piece. However, it is understood that different pieces could be assembled by welding, with glue or by any other technique known to one skilled in the art. The drive pin  20  can be made of plastic, metal or any other material known to one skilled in the art. 
   Referring now to  FIGS. 2 and 3 , it will be seen that, for supporting an object such as a shelf (not shown) on a wall (not shown), a back clip assembly  47  including a back clip  48  and the drive pin  20  can be used. The back clip  48  has a rectangular body  56  with a wall anchor  52 , or an insert, extending therefrom and a rod engaging hook  58  projecting in the opposite direction. The body  56  has a back face  60  abutting the wall once mounted thereon and a front face  62 . The wall anchor  52  preferably extends from the upper portion of back face  60  while the lower portion of front face  62  leads to the engaging hook  58 . The body  56  of the back clip is not limited to a rectangular shape and can have any desired shape. 
   The engaging hook  58  has an upward U-shaped face  66  ending with an upward edge  68 . A shelf (not shown) to be mounted on the back clip  48  has a back rod  70  which is inserted into the U-shaped face  66  of the engaging hook  58 . The upward edge  68  has a groove  72 , preferably in the middle thereof, for insertion of a cross rod  76  ( FIG. 6 ) of the shelf. 
   A reinforcing member  80  can surround the engaging hook  58 , in the middle and below thereof, as shown in  FIG. 2 . The reinforcing member  80  connects the engaging hook  58  to the body  56  and reinforces the back clip  48  when heavy furniture is disposed on the shelf or heavy objects are mounted thereto. 
   The back clip  48  is mounted to the wall with the wall anchor  52 , which cooperates with the drive pin  20 . The wall anchor  52  includes a straight tubular section  84  and a finger section  86 . A passageway  88  extends along the straight tubular section  84 , midway thereof. The passageway  88  has an aperture  90  on the front face  62  of the body  56  and another aperture  92  at the junction of the tubular and finger sections  84 ,  86 . The diameter of the passageway  88  allows the insertion of the drive pin  20  therein. The front face  62  preferably has a cavity  94  surrounding the aperture  90  for insertion of the flange  40  therein. The insertion of drive pin  20  in the passageway  88  stops when the flange  40  abuts the bottom of the cavity  94 . 
   The finger section  86  includes two parallel and laterally expandable fingers  54 . Both fingers  54  have a trailing end  98  and a leading end  100 . The fingers  54  have an outer face  102  and an opposite inner face  104 . The fingers  54  are connected to straight tubular section  84  with hinges  106  allowing an outward pivoting of the fingers  54 . The trailing ends  98  of the fingers  54  have a protuberance  108 , or a male member, on their inner face  104  to avoid the release of the drive pin  20  as it will be described more in details later. The straight tubular section  84  and the outer face  102  of the fingers  54  can be covered with scales  110 . The scales  110  reinforce the anchoring of the wall anchor  52  into the wall. 
   As for drive pin  20 , the back clip  48  is preferably cast or extruded in one piece. Alternatively, the different pieces can be assembled by welding, with glue or by any other technique known to one skilled in the art. The back clip  48  can be made of plastic, metal or any other material known to one skilled in the art. 
   For mounting the back clip  48  to a wall, a hole (not shown) is preferably first made into the wall. Thereafter, the wall anchor  52  of the back clip  48  is inserted therein. Then, the back rod  70  of the shelf is inserted into the engaging hook  58 . To increase the anchoring strength of back clip  48  onto the wall and securing the back rod  70  into the engaging hook  58 , a drive pin  20  is slid into the passageway  88 . The drive pin  20  is preferably inserted in such a manner that the wedge-shaped faces  46  are parallel to the fingers  54 . Referring now to  FIGS. 4 and 5 , there is shown that the fingers  54  pivot outwardly when the drive pin  20  is slid into the finger section  86 . The wedge-shaped faces  46  first penetrate into the finger section  86 , between the fingers  54 , making easier the insertion and reducing the stresses thereon. The insertion of the drive pin  20  stops when the flange  40  abuts the bottom of the cavity  94  and the protuberances  108  are inserted into the groove  50  surrounding the shank  22 . As mentioned above, the insertion of the protuberances  108  into the groove  50  in a male-female engagement prevents the drive pin  20  from being released from the wall anchor  52 . The protuberances  108  are not compulsory since the provision of hinges  106  on the trailing end  98  of the fingers  54  typically creates narrow edges that can also be inserted into the groove  50  to prevent the drive pin  20  from being released from the wall anchor  52 . 
   Referring now to  FIGS. 6 ,  7 , and  8 , it will be seen that the head  28  of the drive pin  20  can be rotated for securing the back rod  70  into the engaging hook  58 . The rotation of head  28  reduces the free spacing over the engaging hook  58  and prevents the back rod  70  from being released when stresses are applied on the shelf. The head  28  of the drive pin  20  allows several width of free spacing over the engaging hook  58 . The position of the head  28  is adjusted depending on the position of the cross rods  76  of the shelf. Referring to  FIG. 6 , there is shown a first position wherein the free spacing over the engaging hook  58  is minimized.  FIGS. 7 and 8  show a second and a third position of the head  28  providing respectively a maximum and a medium spacing over the engaging hook  58 . 
   Referring to  FIG. 9 , there is shown that it is impossible to turn the head  28  into its narrowest position, i.e. the first position shown on  FIG. 6 , when the cross rod  76  of the shelf is engaged into the groove  72 . The head  28  interferes with the cross rod  76 . Now referring to  FIG. 10 , it will be seen that the medium position, i.e. the third position shown on  FIG. 8 , is preferable. Even with the head  28  in the medium position, the free spacing over the engaging hook  58  is too small for release of the back rod  70 . 
   Depending on the shape and the size of the head  28  and its position over the shank  22 , different free spacings can be achieved over the engaging hook  58  or any other object mounted proximate. The free spacing over the engaging hook  58  can thus be adjusted by rotating the head  22  of the drive pin  20 . For the shelf, the free spacing adjustment prevents the release of the back rod  70 , even when there is interference between the back clip  48  and the cross rod  76 . 
   Even if the drive pin has been described in combination with a back clip in, it is understood that it can be used with any wall anchor. 
   The insertion of the protuberance  108  into the groove  50  of the drive pin  20  when the latter is inserted into the passageway  88  of the wall anchor  52  prevents the drive pin  20  to be released from the passageway  88  even when stresses are applied on the wall anchor  82 . 
   One skilled in the art will appreciate that the drive pin  20  can include none or more than one groove. A drive pin having more than one groove can have more than one insertion depth into the passageway of the wall anchor  52  and still be firmly maintained therein even if stresses are applied thereon. 
   One skilled in the art will appreciate that the invention is not limited to back clip assemblies as described in the embodiment hereinabove. It can also applied to wall anchor assemblies including a body section abutting a surface, a wall anchor extending from the body section and being adapted to be inserted into the surface, a passageway extending between the body section and the wall anchor, and a drive pin adapted to be inserted into the passageway. 
   The wall anchor assemblies can be adapted to support any object and does not necessarily include the engaging hook. 
   The back clip assembly and the wall anchor assembly are easy and fast to mount on a surface. 
   The length of the different parts of the back clip and the wall anchor assemblies can vary in accordance with the user&#39;s needs. For example, the length of the wall anchor and the drive pin can vary in accordance with the thickness of the wall where they are inserted. 
   The embodiments of the invention described above are intended to be exemplary only. For example, the support member such as the engaging hook can have any shape or be positioned above the wall anchor. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.