Abstract:
A rocker-type load separating mechanism for a roller conveyor includes a rocker arm and a release mechanism. The rocker arm is pivotally mounted in a discharge zone of the conveyor. The rocker arm is movable between a first load blocking position in which an upstream end of the rocker arm extends into the conveyor pathway to block loads in the holding zone of the conveyor, and a load releasing position in which the upstream end is positioned out of the conveyor pathway to allow those to pass from the holding zone into a discharge zone of the conveyor. A manually actuated release mechanism applies force to the downstream end of the rocker arm to move the rocker arm from a load blocking position to the load releasing position. The force applied by the release mechanism overcomes the weight of loads in the holding zone pressing against the rocker arm when the rocker arm is in the load blocking position.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to gravity type roller conveyors and, more particularly, to a load separating mechanism for separating successive loads on a roller conveyor. 
     BACKGROUND OF THE INVENTION 
     When removing loads from a roller conveyor, it is usually desirable to prevent the entire run of loads from bearing against the lead load at the discharge end of the conveyor so that the lead load can be easily removed. Various types of load spacing mechanisms have been used in the past for separating the lead load from the remaining loads on the conveyor. One type of device uses an actuating lever disposed at the discharge end of the conveyor that is connected by a mechanical linkage to a stop mechanism located at a point further upstream on the conveyor. When the lead load reaches the discharge end of conveyor, the weight of the load presses the actuating lever downward and causes the stop mechanism to move upward into the path of the next adjacent load. When the lead load is removed from the discharge end of the conveyor, the actuating lever returns to an normal position and the stop mechanism is retracted to allow the next load to move down the conveyor. Load separating mechanisms of this type are shown in the patent to vom Stein, U.S. Pat. No. 4,646,909, and Agnoff, U.S. Pat. No. 5,213,189. 
     Several drawbacks have been encountered with this type of load separating mechanism. One problem is the inherent complexity of the load separating mechanism. The load separating mechanisms typically have numerous components that complicate manufacture and assembly. Consequently, these types of mechanisms tend to be relatively expensive to produce. Further, the linkages which connect the actuating lever with the stop mechanism require periodic maintenance to maintain them in proper working order. Therefore, it is desirable to simplify the mechanism as much as possible to reduce costs and maintenance requirements. 
     Another drawback associated with the prior art load separating mechanisms is that the loads are released too quickly after a pallet is removed. The worker responsible for removing loads from the conveyor must have sufficient time to fully remove and dispose of the loads before the next load is released. In most prior art load separating mechanisms, the next load is released immediately as the lead load is lifted or partially removed from the discharge end of the conveyor. The patent to Agnoff addresses this problem by using a damper to delay the return of the actuating lever after a load is removed from the discharge end of the conveyor. This solution, however, further adds to the complexity of the mechanism and increases its cost. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     The present invention relates to a load separating mechanism for a roller conveyor. The load separating mechanism generally comprises a rocker assembly and a release mechanism. The rocker assembly comprises an elongated rocker arm pivotally mounted at the discharge end of the conveyor. A pressure plate or camming surface is disposed at the downstream end of the rocker arm. A stop is connected to the upstream end of the rocker arm. The pivot point of the rocker arm is located downstream from the center of gravity of the rocker arm. Consequently, the force of gravity will cause the upstream end of the rocker arm to naturally assume a lowered or retracted position. The downstream end will naturally assume a raised or extended position. 
     As the lead load rolls to the discharge end of the conveyor, the load will engage the pressure plate at the downstream end of the rocker arm. The weight of the load pushes the downstream end of the rocker arm downward, causing the upstream end to assume a raised position. In this position, the next load on the conveyor engages the stop on the upstream end of the rocker arm and is prevented from travelling further downstream. 
     When the lead load is removed from the conveyor, the weight of the next load pressing against the stop prevents the rocker arm from returning to its natural load releasing position. Therefore, the present invention includes a manually actuated release mechanism. 
     The release mechanism comprises a release lever having a footpad at one end and a roller at the opposite end. The roller engages the underside of the pressure plate or camming surface. When the user presses downward by foot on the footpad, the roller engages the underside of the pressure plate and exerts an upward force on the downstream end of the rocker arm. As the downstream end of the rocker arm is raised, the upstream end lowers, releasing the next load. 
     The present invention provides a relatively simple construction for a load separating mechanism that is inexpensive to manufacture. Further, the reduced complexity of the load separating mechanism reduces maintenance requirements and opportunity for failure. Another advantage of the present invention is that loads are not automatically released when the lead load is removed from the conveyor. The worker responsible for removing loads from the conveyor can release the next load when he is ready. This reduces the chances that the worker will be injured. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing the load separating mechanism and a portion of the roller conveyor. 
     FIG. 2 is an exploded perspective view of the load separating mechanism. 
     FIG. 3 is a partial perspective view of the load separating mechanism showing how it is mounted to the conveyor. 
     FIG. 4 is a partial perspective view of the load separating mechanism showing the release mechanism. 
     FIG. 5 is a longitudinal section view of a portion of a roller conveyor illustrating the load separating mechanism of the present invention in a load blocking position. 
     FIG. 6 is a longitudinal section view of a portion of a roller conveyor showing the load separating mechanism in a load releasing position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings the load separating mechanism  10  of the present invention is shown therein mounted adjacent to the end of an inclined roller conveyor, indicated generally by  100 . The conveyor  100  is a gravity conveyor in which loads move along the conveyor  100  under the force of gravity along an inclined surface. A discharge zone is positioned at the downstream end of the conveyor. The discharge zone is the zone at which the loads are removed from the conveyor. A holding zone is positioned upstream from the discharge zone. The holding zone is where succeeding loads are held while the lead load is being removed from the discharge zone. 
     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 and 2. 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 . An end stop  110  is positioned at the downstream end of each track assembly  102  to prevent the loads from running off the end of the conveyor  100 . In the disclosed embodiment, the stop comprises a stop plate  112  with a lip  114  that extends above the top surface of the rollers  106 . The stop plate  112  is pivotally mounted on a shaft  116  extending between the side rails  104 . Shaft  118  extends below the stop plate  112  to provide support for the stop plate  112 . The construction of the stop plate  112  is not an important aspect of the present invention. Those skilled in the art will recognize that other forms of stops can be used. For example, the stop  110  could comprise a simple, flat plate welded or bolted to the end of the track assembly. 
     At least one of the track assemblies  102  also includes a brake assembly  120  disposed a predetermined distance from the discharge end of the conveyor  100 . The brake assembly  120  is disposed in the holding zone where loads are held back by the load separating mechanism  10 . The purpose of the brake assembly  120  is to slow the load that is second in line in the holding zone after the lead load is removed while the load that is first in line in the holding zone moves into the discharge zone of the conveyor. This prevents two loads from being released at the same time. Additionally, the brake assembly  120  prevents the loads from being jolted too severely when the load impacts the load separating mechanism. Since brake assemblies  120  are well known to those skilled in the art, a detailed description of the brake assembly is omitted. 
     The load separating mechanism  10  is adapted to mount to one of the track assemblies  102  as shown in FIG.  3 . In the disclosed embodiment, the load separating mechanism  10  mounts on the center track assembly  102 , though it could mount to any of them. The purpose of the load separating mechanism  10  is to separate the lead load in the discharge zone from subsequent loads so that the lead load can be easily removed from the conveyor  100 . 
     The load separating mechanism  10  generally includes a housing  12 , a rocker assembly  50 , and a release mechanism  70 . The housing  12  serves to mount the load separating mechanism  10  to one of the track assemblies  102  of the conveyor  100 . The rocker assembly  50  functions to separate loads on the conveyor. The rocker assembly  50  moves between a load blocking position in which loads are held back in an holding zone of the conveyor, and a load releasing position in which loads from the holding zone are allowed to flow downstream into the discharge zone. The rocker assembly  50  naturally assumes the load releasing position. When a load flows into the discharge zone, the lead load engages the rocker assembly  50 , causing it to assume the load blocking position. Since the weight of the load in the holding zone prevents the rocker assembly  50  from returning to the load releasing position, the release mechanism  70  is provided to release loads from the holding zone. In the preferred embodiment, the release mechanism  70  is manually actuated by a foot. 
     The housing assembly  12  comprises two nested channels referred to herein as the outer channel  14  and a inner channel  30 . The outer channel  14  includes a top flange  16 , a bottom flange  18 , and a side wall  20 . The inner channel  30  includes a top flange  32 , a bottom flange  34 , and a side wall  36 . The outer and inner channels  14 ,  30  are sized so that the inner channel  30  nests inside the outer channel  14 . The outer and inner channels  14 ,  30  each include an opening  22  and  38 , respectively, formed in their top flanges  16 ,  32 . The purpose of the openings  22 ,  38  will be explained below. 
     The outer channel  14  includes bolt holes  24  at opposing ends of the channel  14  which align with similarly spaced bolt holes  40  in the inner channel  30 . Bolts  26 ,  42  pass through respective sets of aligned bolt holes  24 ,  40  to secure the load separating mechanism  10  to a side rail  104  of the track assembly  102 . As will be described below, the bolts  26 ,  42  also serve as pivot members for the rocker assembly  50  and release mechanism  70 . 
     The rocker assembly  50  comprises an elongated rocker arm  52  including a downstream end  54  and an upstream end  56 . A pivot hole  58  is formed in the rocker arm  52  at a point downstream from the gravity center of the rocker arm  52 . A pivot bushing  60  is inserted into the pivot hole  58 . The pivot bushing  60  serves both as a pivot member for the rocker arm  52  and as a spacer to maintain proper spacing between channels  14 ,  30 . Bolt  26  passes through bushing  60  so that the rocker arm  52  pivots about the axis of bolt  26 . Since the pivot point is located downstream from the center of the rocker arm  52 , the upstream end  56  of the rocker arm  52  naturally assumes a lowered position with the downstream end  54  assuming a raised position. This position is referred to herein as the load releasing position. Alternatively, the pivot hole  58  could be disposed upstream from the center of gravity of the rocker arm  52  so that the rocker arm  52  naturally assumes a load blocking position. In this embodiment, the rocker arm  52  would return to the load blocking position before it is engaged by the load. A biasing means, such as a spring, could also be used to bias the rocker arm  52  to the desired position, though such is not the preferred embodiment. 
     A pressure plate  66  is secured to the downstream end  54  of the rocker arm  52 . When the rocker arm  52  is in the load releasing position, the pressure plate  66  extends through the openings  22 ,  38  in the channels  14 ,  30  to a point above the top surface of the conveyor  100 . Thus, when a load is discharged from the holding zone, the load will engage the pressure plate  66  and press it downward. The pressure plate  66  is curved so that the upper surface of the pressure plate  66  functions like a camming surface. When engaged by a load, the load rides up onto top surface of the pressure plate  66  forcing the downstream end  54  of the rocker arm  52  into a lowered position. In this position, the upstream end  56  is raised. This position is referred to as the load blocking position. 
     A stop  64  is disposed at the upstream end  56  of the rocker arm  52 . The stop  64  includes a triangular gusset plate  68  to strengthen the stop  64 . The geometry of the stop  64  is not a material aspect of the invention. The stop  64  may be a flat plate, or may be angled at the top as shown in FIG.  3 . When the rocker arm  52  assumes a load blocking position, the stop  64  is raised into the path of any loads in the holding zone. Loads in the holding zone will travel downstream until the load engages the stop  64 , at which time the load is prevented from moving into the discharge zone. 
     The release mechanism  70  is shown in FIG.  4 . The release mechanism  70  includes a lever arm  72 . A pivot bearing  80  is attached roughly at the center of the lever arm  72 , although the precise location of the pivot bearing  80  is not critical. The lever arm  72  is bent at one end to form a footpad  74 . A roller mount  76  is connected to the opposite end of the lever arm  72 . A roller  78  is rotatably mounted to the roller mount  76 . 
     The release mechanism  70  is held in place by bolt  42 , which passes through the pivot bearing  80 . Thus, the release mechanism  70  rotates about the axis of the bolt  42  between a raised position (footpad raised) and a lowered position (footpad lowered). The release mechanism  70  assumes the raised position when the rocker assembly  50  is in the load blocking position (downstream end lowered) and the lowered position when the rocker assembly  50  assumes the load releasing position (downstream end raised). The roller  78  engages the underside of the pressure plate  66 . When the rocker arm  52  is forced downward by the weight of a load in the discharge zone, the pressure plate  66  presses down on the roller  78 , causing the footpad  74  to assume a raised position. When the lead load is removed from the discharge zone, the weight of the loads in the holding zone, acting against the stop  64 , prevents the rocker assembly  50  from returning to the load releasing position. To overcome the force of the loads in the holding zone, the worker can press the downward by foot on the footpad  74 . When the footpad  74  is pressed downward, the roller  78  applied an upward force to the underside of the pressure plate  66 , raising the downstream end  54  of the rocker arm  52 . 
     FIGS. 5 and 6 illustrate the operation of the load separating mechanism  10 . In FIG. 6, a load has just been released from the holding zone and is travelling into the discharge zone of the conveyor  100 . Note that the stop  64  on the upstream end of the rocker arm  52  is lowered permitting the load to flow into the discharge zone. As the load flows into the discharge zone, it engages the pressure plate  66  and presses down on the rocker arm  52  as seen in FIG.  5 . The weight of the load causes the stop at the upstream end of the rocker arm  52  to be raised into the path of the next load preventing it from entering the discharge zone. To release the next load (the first load in the holding zone), the worker steps on the footpad  74  and presses it down as shown in FIG.  6 . 
     The load separating mechanism  10  of the present invention provides a relatively simple solution to the problem of separating loads on a conveyor. The mechanism has relatively few moving components which are of relatively sturdy construction. Therefore, the load separating mechanism  10  of the present invention is relatively inexpensive to produce, operate, and maintain. Further, the load separating mechanism allows the worker to determine when to release loads from the holding zone so that the worker is not caught unaware.