Abstract:
A retainer for controlling the movement of objects along a conveyor including a substantially L-shaped retaining arm pivotally mounted to the conveyor and having a toe section and a leg section. A swing arm is pivotally connected to the leg section and includes a roller rotatably mounted to the second end of the swing arm. A biasing member has a first end attached to the conveyor frame and a second end attached to the swing arm. A link arm is connected to the roller and is selectively actuatable for moving the roller to a first position between the conveyor frame and the retaining arm for maintaining the leg section below the retaining arm pivot point and the toe section above the conveyor frame to stop the objects. The link arm is also actuatable to a second position in which the retaining arm pivot point, swing arm pivot point, and link arm are substantially aligned providing for the retaining arm toe section to be positioned below the retaining arm pivot point to allow the objects to pass on the conveyor.

Description:
FIELD OF THE INVENTION 
     The present direction is directed to a retainer for controlling the movement of objects along a conveyor and, more particularly, to a retainer having a pivoting retaining arm selectively positionable such that one end pivots above and below the height of the conveyor. 
     BACKGROUND OF THE INVENTION 
     Typically, a conveyor system includes a plurality of rollers rotatably mounted in a conveyor frame so as to define a path upon which articles are conveyed. The conveyor may include drive rollers for moving the materials along the conveyor length, belts, or preferably the conveyor may be gravity fed having free-moving rollers. To most effectively utilize the conveyor, it is often necessary to separate the goods and control the positioning. This may be necessary to allow for a user to individually handle or remove a single object, effectively route the materials to the appropriate destination, or to ensure that adjacent materials do not come in contact which may cause damage to the materials. 
     One type of presently available system includes an electrically powered retaining arm. These systems provide for accurate control of goods along the conveyor, however, they are often expensive to install and require a large amount of maintenance to ensure they operate effectively. Additionally, powered conveyors are more effective when permanently positioned at a single station and are not effective for portable conveyors that are used in a variety of situations such as loading and unloading from trucks and loading docks. Powered retainers using electrically controlled retaining arms may also not be available for use in wet environments such as a loading dock, tractor-trailer, etc. 
     There have further been numerous mechanically operated retainer mechanisms. However, these often require many intricate moving parts that are susceptible to wearing out or being damaged during use. These mechanisms may also become stuck in position resulting in the retention of all goods on the conveyor, or potentially worse, fail to retain materials when a load is placed upon them. 
     Thus, a straight-forward mechanical retainer is needed that effectively separates materials along a conveyor without being prohibitively expensive or require a large amount of maintenance. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a retainer for controlling the movement of materials along a conveyor. The invention provides for a user to selectively actuate the retaining arm between a first position that extends above the conveyor for stopping goods moving on the conveyor, and a second position having the arm under the conveyor allowing for goods to move along the conveyor. 
     The invention includes a retaining arm mounted to the conveyor and having a first end and a second end and a pivoting about a point there-between. A swing arm is pivotally attached to the retaining arm and includes a roller that slides against and abuts a channel or conveyor frame applying a force to the retaining arm. A link rod is connected to the roller for moving between a first load blocking position having the roller between the conveyor frame and the retaining arm for positioning the downstream end of the retaining arm above the conveyor frame. The link rod can be positioned in a second load releasing position having the roller and swing arm extending outward from the retaining arm resulting in the downstream end of the retaining arm being below the conveyor frame. 
     Preferably, the retaining arm is substantially L-shaped having a toe section that extends above the conveyor height and a leg section. A biasing member may be attached between the conveyor and the roller to pull the roller to the first position between the conveyor frame and retaining arm. To assist in maintaining the roller in the first position with the toe above the conveyor height, the roller is preferably positioned over-center of said swing arm pivot point. Most preferably, the roller is just over center to ensure the retaining arm stays in position but does not require a large amount of force by the link rod to pull it into the second position. 
     Another embodiment of the invention features the swing arm pivotally attached to the retaining arm at a point below where the retaining arm is pivotally connected to the conveyor. This alignment provides for the retaining arm pivot point, swing arm pivot point, and link arm being substantially aligned when the swing arm is pulled by the link rod in the second position. This provides for the retaining arm to move about its pivot point to control the flow of materials on the conveyor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of the pallet retainer; 
     FIG. 2 is a side view illustrating the pallet retainer in the load blocking position; 
     FIG. 3 is a side view illustrating the pallet retainer moving between the load blocking position and the load releasing position; 
     FIG. 4 is a side view of the load retainer in the releasing position; 
     FIG. 5 is a top view of the load retainer in the load releasing position; 
     FIG. 6 is a cross-sectional of the pallet retainer taken through line  6 — 6  of FIG. 2; and 
     FIG. 7 is a cross-sectional view of the pallet retainer taken through line  7 — 7  of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and particularly to FIG. 1, the pallet retainer of the present invention is shown therein and indicated generally by the numeral  10 . The pallet retainer  10  is mounted to a conveyor  100 . The roller conveyor  100  comprises three laterally spaced track assemblies  102  that are attached to a support frame (not shown). The track assemblies  102  are shown in FIGS.  1 . Each track assembly  102  includes a pair of side rails  104  with a series of rollers  106  disposed between the side rails  104 . The rollers  106  are mounted on roller shafts  108  that extend between the side rails  104 . The roller shafts  108  can be fixed to the side rails  104  by any suitable means, such as by bolting or welding. In the disclosed embodiment, adjacent rollers  106  are staggered as shown in FIG. 1, however, it is understood that the present invention may be used on a variety of conveyor systems having various track assembly&#39;s and roller configurations. 
     The pallet retainer  10  mounts to one of the track assemblies  102  as shown in FIG.  1 . In the disclosed embodiment, the pallet retainer  10  is mounted on the center track assembly  102 , though it could mount to any of them. The purpose of the pallet retainer  10  is to engage loads on the conveyor and prevent the loads from moving downstream until released. 
     The pallet retainer  10  generally includes a housing  12 , a load stop  30 , an actuator  40 , and a link assembly  50 . The housing  12  encloses the other components and provides a means for mounting the pallet retainer  10  to the conveyor  100 . The load stop  30  engages loads on the conveyor  100  to prevent the loads from moving further downstream until released. The load stop  30  is movable between a load blocking position in which loads are blocked, and a load releasing position in which loads are released. The actuator  40  is used to move the load stop  30  between the load blocking and load releasing positions. The link assembly  50  connects the actuator to the load stop  30 . 
     The housing assembly  12  comprises two nested channels, referred to herein as the outer channel  14  and the inner channel  16 . The outer and inner channels  14 ,  16  are sized so that the inner channel  16  nests inside the outer channel  14  as best seen in FIG.  6 . The outer channel  14  and inner channel  16  define an enclosed space that contains the link assembly  50 . The load stop  30  extends from one end of the nested channels  14 ,  16 . The actuator  40  extends through an opening  18  formed in the top flanges of the nested channels  14 ,  16 . 
     The channels  14 ,  16  are held together by bolts  22 ,  24  which pass through aligned bolt holes (not shown) at opposite ends of the channels  14 ,  16 . As will be described below, the bolts  22 ,  24  also serve as pivot members for the load stop  30  and actuator  40 , respectively. 
     The load stop  30 , shown in FIGS. 2-4, comprises an L-shaped rigid body  32  that is pivotally mounted at one end of the nested channels  14 ,  16 . The rigid body  32  includes a rear portion  34  and a forward load engaging portion  36 . The rigid body  32  is mounted for pivotal movement about a fixed axis and extends from one end of the nested channels  14 ,  16 . The rigid body  32  is movable about the fixed axis between a load engaging position (shown in FIG. 2) and a load releasing position (shown in FIG.  4 ). More particularly, the rigid body  32  pivots about bolt  22 , which passes through a pivot opening in the rigid body  32 . Thus, bolt  22  functions as a pivot member for the rigid body  32 . In the load blocking position, the load engaging portion  36  extends above the top surface of the rollers  106  to block loads being conveyed, as seen in FIG.  2 . In the load releasing position, the load portion member  36  is lowered below the conveying surface, as seen in FIG. 4, so loads are free to move downstream. 
     The actuator  40  moves the load stop  30  between the load blocking and load releasing positions. The actuator  40  is mounted upstream from the load stop  30 , though it could also be mounted downstream. The actuator  40  comprises a lever  42  with a handle  44  at its upper end. Lever  42  pivots about a fixed axis between a first position illustrated in FIG.  2  and second position illustrated in FIG.  4 . The lever  42  includes a pivot opening  46  at a central portion thereof through which bolt  24  passes. Thus, bolt  24  functions as a pivot member for the lever  42 . The lower end  48  of the lever  42  is connected to the link assembly  50 . 
     Link assembly  50  operatively connects the lever  40  to the load stop  30 . When the lever  40  is in the first position (shown in FIG.  2 ), the load stop  30  assumes a load blocking position. Conversely, when the lever  40  is in the second position (shown in FIG.  4 ), the load stop  30  assumes a load releasing position. 
     Link assembly  50  is a planar linkage including two or more free-floating links. In the preferred embodiment, the link assembly has only two floating link elements, though more than two could be used. The disclosed embodiment of the link assembly  50  includes a link rod  52  and a pair of parallel swing arms  72  illustrated in FIG.  7 . The link rod  52  functions as a first floating link element. The swing arms  72  function as a second floating link element. For purposes of this application, the term floating link element means a link element whose pivot points are movable. The link rod  52  is connected at one end to the actuator  40  and at the opposite end to the swing arms  72 . The swing arms  72  are connected at one end to the load stop  30  and at the opposite end to the link rod  52 . 
     The link rod  52  includes a forward end  54  and a rearward end  56 . The rearward end  56  of the link rod  52  is pivotally connected to the lower end of the lever  40  to from a hinge joint  48  that permits rotational movement between the link rod  52  and lever  42 . The link rod  52  includes a flattened portion with an opening (not shown) therein to receive a fastener  58 . Fastener  58  pivotally connects the rear end  56  of link rod  52  to the lower end  48  of the lever  42  to make the hinge joint  48 . The hinge joint  48  defines a first movable pivot point for the link assembly  50 . The forward end  54  of the link rod  52  is connected to the swing arms  72  by a unshaped clevis  62 . Clevis  62  has a base member  64  and a pair of arms  66  as best seen in FIG.  5 . Clevis  62  is mounted to the forward end  54  of the link rod  52 . The forward end  54  of the link rod  52  is externally threaded and passes through an opening (not shown) in the base member  64  of the clevis  62 . The clevis  62  is rigidly secured on the link rod  52  by nuts  70 , which allow for some adjustment to the effective length of the link rod  52 . The arms  66  of the clevis  62  are connected to the upper end of respective swing arms  72  by a fastener  68 , such as a clevis pin or bolt and nut combination, to form a hinge joint  76  that permits rotational movement between the link rod  52  and swing arms  72 . Hinge joint  76  defines a second movable pivot point for said link assembly  50 . A roller  80 , whose function is described below, is disposed between the arms  66  of the clevis  62  and is rotatably journalled on the fastener  68 . Thus, fastener  68  functions as an axle for the roller  80 . 
     The swing arms  72  connect the forward end  54  of the link rod  52  to the load stop  30 . The swing arms  72  are disposed on opposite sides of the load stop  30 , as seen in FIGS. 5 and 7. The swing arms  72  are secured to the rear portion  34  of the load stop  30  by a fastener  74 , such as a clevis pin or bolt and nut combination, to form a third hinge joint  77 . Hinge joint  77  defines a third moving pivot point for the link assembly  50 . In the preferred embodiment of the invention, hinge joint  77  is disposed below the fixed axis of the load stop  30  when the rigid body  32  is in a horizontal position. While two swing arms  72  are disclosed, those skilled in the art will appreciate that only one is required. 
     In a preferred embodiment, a biasing member  84 , such as a tension coil spring, urges the entire assembly to the load blocking position. One end of the spring  84  is connected to fastener  68 . The opposite end is connected to a bolt  26 . 
     In use, the rigid body  32  pivots between the first load blocking position illustrated in FIG.  2  and second load releasing position illustrated in FIG.  4 . In the load blocking position, the hinge joint  76  is displaced forward of hinge joint  77  to an over-center position and the roller  80  and trapped against the inner surface of the channel  16 . The swing arms  72  push downward on the rear end  34  of the rigid body  32  to hold the rigid body  32  in the load blocking position. In this position, the load engaging portion  36  extends above the surface of the conveyor  100  to block loads travelling down the conveyor  100 . The “over-center” position of hinge joint  76  relative to hinge joint  77  prevents the roller  80  and swing arm  72  from rotating when a load pushes against the load engaging portion  36 . By contrast, if hinge joint  76  was positioned short of the center line of hinge joint  77 , a force on the load engaging portion  36  could cause the swing arm  32  to rotate clockwise, as shown in FIG. 2, resulting in the release of loads held by the load stop  30 . Preferably, the hinge joint  76  is not placed a large degree over the center line of hinge joint  77  because this may cause the roller  80  to become locked against the channel  16  requiring a larger amount of force to be applied to move the load stop  30  to the load releasing position. The biasing member  84  assists in pulling the roller  80  into the first position, but may not be enough force to maintain the roller  80  when a load is placed on the load stop  30 . 
     To release a load, the actuator  40  is pushed forward. When the actuator  40  is pushed forward to the second position, the link rod  52  is pulled back in the direction of arrow A in FIG.  3 . At the start of this rearward motion, the roller  80  is constrained by the channel  16  to follow a linear path defined by the inner surface of the channel  16 . Eventually, the rotation of the swing arm  72  moves the roller  80  in an arc away from the channel  16 . Further rearward movement of the link rod  52  causes the swing arm  72  to lift up on the rear portion  34  of the rigid body  32  to rotate it the load releasing position. When the actuator  40  is pushed all the way forward, swing arms  72  rotate downward so that the hinge joints  76  and  77  lie in a straight line with the fixed axis of the load stop. In this position, the swing arms  72  rotate the load stop  30  to the load releasing position. When the actuator  40  is released, the link rod  52  is pulled forward by the biasing member  84 . As the link rod  52  moves forward, the swing arm  72  rotates up until the roller  80  once again contacts the surface of the channel  16  which acts as a guide. At this point, the movement of the roller  80  and hinge joint  76  is further constrained against vertical translational movement by the channel  16  and travels forward in a linear path. By preventing vertical translational movement of the hinge joint  76 , the channel  16  causes the swing arm  72  to apply a downward force on the rear end of the load stop  30  as the link rod  52  is moves forward. That is, once the roller  80  engages the channel, further forward movement of the link rod  52  causes the swing arms  32  to rotate and push down on the load stop  30 . The force applied by the swing arms  72  to the load stop  30  rotates the load stop  30  to the load blocking. 
     Those skilled in the art will be appreciate that the link assembly can be differently arranged and achieve the same results. For example, the swing arms could rotate downward instead of upward and engage the bottom flange of the channel  16 . In this arrangement, the swing arms  72  would push up on the load stop  30  when the link rod  52  moves forward to rotate the load stop  30  to the load releasing position. The common element is that translational movement of the link assembly is constrained causing the link assembly to exert a force on the load stop  30 . 
     Certain modifications and improvements will occur to those skilled in the art upon a reading of the foregoing description. In the foregoing description, like referenced characters designate like corresponding parts throughout the several views. Also, it is to be understood that such terms as “forward”, “rearward”, “left”, “right”, “upwardly”, “downwardly”, “upstream”, and “downstream”, and the like are words of convenience and are not to be construed as limiting terms. It should be understood that all such modifications have been deleted herein for the sake of conciseness and readability but are properly with the scope of the following claims.