Overshot loader

Abstract

This disclosure provides an overshot loader mechanism for transporting material in an overhead trajectory from a filling to a discharge position. The overshot loader mechanism includes at least one control arm, pivotally connected at one end to a chassis frame, and at the other end to a thrust end of the load arm, and a bucket pivotally connected to a load end of the load arm. Rotation of the control arm about its pivotal connection moves the thrust end of the load arm from a terminal high point, where the load end of the load arm is located towards the bottom of its trajectory for bucket filling, to a terminal low point, where the load end of the load arm is located towards the height of its trajectory. This configuration reduces the centre of gravity of the loader mechanism, while retaining sufficient bucket height to clear the vehicle's operator cab.

1 . An overshot loader mechanism for transporting material in an overhead trajectory from a filling position at a loading end of a vehicle, to a discharge position at a discharge end of the vehicle, the overshot loader mechanism comprising;
 a chassis frame for supporting the body of the vehicle,   at least one control arm, for controlling the movement of at least one load arm, one end of the control arm being pivotally connected to the chassis frame and the other end of the control arm being pivotally connected to a first/thrust end of the load arm;   and a bucket pivotally connected to a load end of the load arm,   in which rotation and/or counter rotation of the control arm about its pivotal connection to the frame causes movement of the thrust end of the load arm, from a terminal high point when the bucket and load end of the load arm is located towards the bottom of its trajectory for bucket filling and/or discharge, and a terminal low point when the bucket and load end of the load arm is located towards the height of its trajectory, thus reducing the centre of gravity of the loader mechanism, while retaining a bucket height sufficiently high enough to clear an operator cab located on the vehicle.   
     
     
         2 . The overshot loader mechanism as claimed in  claim 1 , in which the mechanism further comprises at least one cam rail extending at least partway along the length of the chassis frame, and profiled to support the load arm in transporting the bucket through an appropriate trajectory. 
     
     
         3 . The Overshot loader as claimed in  claim 2  in which the load arm includes a roller secured at a point along its length, the load arm roller being receivable in use on the cam rail, for guiding and supporting movement of the load arm from a filling position to a discharge position. 
     
     
         4 . The overshot loader mechanism as claimed in  claim 1  in which the mechanism comprises a cross shaft, pivotally mounted across the breadth of the chassis frame and a control arm mounted at either end of the cross shaft and in which each control arm is pivotally connected to a load arm. 
     
     
         5 . The overshot loader as claimed in  claim 4  in which the mechanism further comprises two cam rails, locatable on opposing sides of the chassis frame. 
     
     
         6 . The overshot loader as claimed in  claim 5  in which each cam rail further comprises two sections; a loading cam rail section, extending from the loading end of the chassis frame towards the middle of the chassis frame, and a discharge cam rail section, pivotally connected to the loading cam rail section and extending from about the middle of the chassis frame towards the discharge end of the chassis frame. 
     
     
         7 . The overshot loader as claimed in  claim 6  is which the profile of the loading cam rail section is generally convex and the profile of the discharge cam rail section is generally concave. 
     
     
         8 . The overshot loader as claimed in either of  claim 6  or  7 , in which the discharge cam rail section is pivotable to allow for the load arm to drop the bucket closer towards the ground, to a spreading position. 
     
     
         9 . The overshot loader as claimed in any one of  claims 6  to  8  in which the loading cam rail section includes a latch located at its lowest end, for engaging the roller when in the filling position, thereby allowing downward pressure on the bucket during filling. 
     
     
         10 . The overshot loader as claimed in any one of  claims 6  to  8 , in which a cam plate is affixed to the load arm, and a roller, configured to engage with the cam plate, is affixed to a bracket rigidly mounted to the chassis frame, to allow a downforce to be applied to the bucket during filling. 
     
     
         11 . The overshot loader as claimed in any one of  claims 6  to  10  in which the geometry of the cam rail, the position of the roller on the load arm and the effective mounting point of the thrusting end of the load arm at its terminal low point, provide for a reduced overhead trajectory of the bucket and a reduced centre of gravity when transferring the load from the loading end of the vehicle to the discharge end of the vehicle, and ensures extension of the bucket at the loading end for bucket filling and at the discharge end to provide space for discharge into a receiver or to drop the bucket close to the ground. 
     
     
         12 . The overshot loader as claimed in any one of  claims 1  to  11  in which rotation and counter rotation of the control arm is driven by hydraulic cylinders, electric actuation or other appropriate power source. 
     
     
         13 . The overshot loader as claimed in  claim 12  in which a single stroke of the power source is all that is required to drive the thrust end of the load arm incrementally from its terminal high point to its terminal low point thereby powering the bucket from its filling position incrementally to the top of its trajectory, and a single reverse stroke of the power source is all that is required to drive the thrust end of the load arm incrementally from its terminal low point back towards its high point, thereby powering the bucket from its high position incrementally towards its discharge position or spreading position at the discharge end of the vehicle. 
     
     
         14 . The overshot loader as claimed in  claim 13  in which a single stroke of the power source is all that is required to drive the thrust end of the load arm incrementally from a high point to its terminal low point, thereby powering the bucket from its discharge position or spreading position incrementally back to the top of its trajectory, and a single reverse stroke of the power source is all that is required to drive the thrust end of the load arm incrementally back to its terminal high point, thereby powering the bucket from its high point back to its filling position below ground level at the filling end of the vehicle. 
     
     
         15 . The overshot loader as in  claims 12  and  13  in which a full cycle from bucket filling to discharge and back to its filling position requires one single stroke of the power source followed by a reverse stroke, and then once again requires a single stroke of the power source followed by a reverse stroke. 
     
     
         16 . The overshot loader as claimed in any one of  claims 13  to  15  in which the triggering of the power source is achieved with electronically controlled hydraulics or other suitable means. 
     
     
         17 . The overshot loader as claimed in any one of  claims 1  to  16  in which the bucket is connected to the load arm through a system of pins and linkages, and is articulated under load by a power source. 
     
     
         18 . The overshot loader as claimed in any one of  claims 1  to  17  in which the position of the bucket in relation to the load arm, during its trajectory from filling to discharge is continually variable to prevent spillage of the contents on the buckets journey from filling to discharge. 
     
     
         19 . The overshot loader as claimed in any one of  claims 1  to  18 , in which the chassis frame includes axles and wheels when on a wheel loader or endless tracks when fitted to a crawler type of vehicle.