Abstract:
A dumper apparatus and method for transferring bulk parts from a parts container into a receptacle includes an outer hopper having a parts container cradle pivotally mounted therein. The hopper is swung up from an upright front end up position while the cradle is thereby also simultaneously pivoted thereby by a linkage from a horizontal position, causing the parts to be dumped from the container into the hopper and thence from the hopper into the receptacle as the hopper reaches a front end downwardly inclined position.

Description:
BACKGROUND OF THE INVENTION 
   This invention concerns dumpers, typically used to transfer loose parts such as metal fasteners in bulk during various processing steps, particularly in metal finishing operations. 
   The parts are commonly transported in tote boxes which need to be emptied into an opening of a container used in processing the parts, such as a perforated barrel used in plating, phosphating, etc. Tote boxes are open topped sturdy boxes constructed of metal containers having a metal nose at the front end for directing parts emptied out of the tote box by being tipped forwardly. The filled tote boxes are usually too heavy for manual handling and transferring the contents of a dozen or more tote boxes per hour is typical in any given processing operation. This results in much time being consumed in handling the tote boxes using various lifts. 
   The parts must be transferred from the tote box into the barrel to begin the finishing process. This transfer can be by dumping the parts directly from the tote box into the barrel, or it can include an intermediate dumping from the tote box into other devices, from which the parts are then fed into the barrel. In either case, it is standard industry practice to use a conventional device called a tote box dumper to automatically dump the parts out of the tote box. 
   There are many different configurations of tote box dumpers available on the market from companies that specialize in material handling equipment, and their basic method of operation is the same. The tote box is loaded into the hopper of the tote box dumper, where it is constrained in either a passive manner by the configuration of the hopper, or in an active manner by some form of actuated device. The hopper is then rotated about a pivot point by some form of automation, usually hydraulic or electric, which causes the hopper and the tote box within it to be raised and pivoted, tilting the tote box forward in the process. As the tote box tilts forward the parts dump out of the tote box and onto the forward face of the hopper where they slide down toward the barrel opening. The system is always designed such that as the exit nose of the pivoting hopper approaches the opening of the barrel the parts that are sliding down the hopper face enter into the barrel. When the hopper rotates to its maximum practical angle, which is typically about 135°, the exit nose of the hopper protrudes into the opening of the barrel, and all of the parts have theoretically dumped out of the tote box and into the barrel. The tote box dumper then rotates and lowers the hopper and tote box back to their down position. The dumping process is also similar in the case when the material is being dumped into an intermediate device rather than directly into the barrel. 
   A traditional problem with this dumping process is that for many tote box loads some of the parts do not in fact leave the hopper and/or the tote box when they are dumped. While the magnitude of the problem is dependent on the geometry and quantity of the parts and the configuration of the tote box, it occurs for two primary reasons. First, parts will sometimes become trapped between the front of the tote box and the face of the hopper during the dump process, and then stay in the hopper when it returns to its down position. This happens because the tote box is placed directly up against the front face of the hopper, and when the parts start to dump out of the tote box, the hopper face is often not yet tilted far enough downward to cause the parts to slide toward the hopper exit nose, so the parts instead slide backward toward the bottom of the hopper and get trapped under the tote box. Even when a standoff is used to separate the tote box from the front face of the hopper, some parts can still get trapped. Second, parts will sometimes get caught around the rim or corners of the tote box itself, and then remain in the tote box when it returns to its down position. 
   For these reasons, the operator needs to continually monitor the dumping process and manually retrieve any parts that were not dumped. If the operator does not notice and remove the retained parts, they could become mixed with a following load of different parts, which then creates the problem of “part mixing” for the customer. In today&#39;s quality conscious world, the problem of part mixing has become very important, and a growing number of metal finishing customers are demanding “zero parts per million” mixed parts. 
   Some commercially available tote box dumpers address the part mixing problem by pivoting the hopper and tote box a full 180° instead of the typical 135°. This orients the tote box completely upside down, which makes it much less likely for any parts to remain in the tote box or to be trapped between the tote box and the hopper walls. Drawbacks to various versions of these dumpers are that they utilize a more complex dual-stage hydraulic mechanism to create the additional rotation, that they require adjustable tote box clamp mechanisms that can restrict part flow, that they require more valuable space above the barrel area, or that they use multiple linkage mechanisms which move the hopper in such a way that it cannot be used to feed the parts directly into a barrel mouth. 
   An object of the invention is to provide an apparatus and method for dumping loose parts ensuring that all of the parts can be dumped directly into a receiver and to thereby eliminate the problem of part mixing, while not requiring complex bulky apparatus, and tote box clamps. 
   SUMMARY OF THE INVENTION 
   These objects and others which will become apparent upon a reading of the following specification and claims are achieved by a two stage dumper apparatus including a hopper closed at the bottom and on three sides and open at the front. The hopper is initially vertically positioned with its rear end wall extending horizontally. A tote box cradle is provided, mounted within the hopper with clearance spaces between it and the hopper, shaped and sized to slidably receive a loaded tote box and locate it so that its nose projects forwardly at the front end of the tote box cradle. The tote box cradle is pivoted at its forward end to the sidewalls of the hopper so as to be suspended well above the bottom wall of the hopper to allow pivoting up of the rear end of the cradle and tote box. In their initial position, the cradle and tote box extend horizontally. 
   The hopper itself is pivoted to a fixed frame at its forward end by bearings disposed at the top of the hopper when in its initial position resting its rear end wall. 
   To carry out a dump, a lift drive pulls up the hopper rear end to swing the hopper upwardly about its pivot. A pair of angled link arms are each pivoted at one end to the fixed frame and their other ends are each pivoted to a cross tube mounted to top of the cradle, so that as the hopper is swung up, the cradle (and the tote box received therein) is simultaneously tilted about is forward end pivot, at a greater rate than the hopper due to the link arm geometry. As the tote box approaches a vertical position, it begins to dump its contents into the hopper which is positioned below the tote box with its end wall extending up to thereby confine the parts dumped from the tote box within the hopper which slide to the rear of the upwardly inclined hopper. 
   As upward swinging of the hopper continues, the tilting of the cradle and tote box also continues, until the tote box is completely inverted and the hopper has its forward open end inclined downwardly and received into a receptacle opening so that the parts dumped in the hopper now slide out of the forward end of the hopper and into the receptacle opening. 
   Any parts remaining in the hopper can be discharged by repeating the final motion of the hopper from a partially retracted position. 
   Thereafter, the hopper and tote box cradle are both moved back to their initial position by lowering of the hopper preparatory to loading another filled tote box into the cradle. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevational view of a dumper apparatus according to the invention, shown next to a perforated barrel receptacle positioned to receive parts. 
       FIG. 1A  is a simplified side elevational view of some of the major components shown in FIG.  1 . 
       FIG. 2  is a front elevational view of the apparatus shown in FIG.  1 . 
       FIG. 3  is a plan view of the apparatus shown in  FIGS. 1 and 2 . 
       FIG. 4  is a simplified side elevational view of the apparatus in the partially raised position of the hopper and tote box cradle with parts dumping from a tote box into the hopper. 
       FIG. 5  is a side elevational view of the apparatus in the fully raised position, dumping parts into the receiving barrel. 
   

   DETAILED DESCRIPTION 
   In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims. 
   Referring to the drawings, the dumping apparatus  10  includes a fixed support frame  12  constructed from box members  14  as by welding. 
   A hopper  16  is pivotally connected to the support frame  12  by members  18  welded to the forward position of the bottom plate  20 , each extending to a respective bearing  22  mounted to upright channel frame members  24 . The hopper  16  is shown in its initial or start vertical position, with its forward end up and a bottom plate  20  extending vertically. 
   The bottom plate  20  and a pair of sidewalls  26  and a rear end wall  28  create an open topped rectangular enclosure. While the forward end of the hopper  16  is substantially open, a part flow control cross bar  30  is provided as well as optional fingers  32  for orienting long parts so as to prevent tangles. 
   A tote box cradle  34  is comprised of two sides  36  and a bottom wall  38  and a front wall  42  forming a box open at a rear side able to receive a parts container comprised of a tote box  40 , slid forwardly against the front wall  42  comprising a front stop allowing the cradle  34  to retain the tote box  40  therein as the cradle  34  is swung up from its initial horizontal position. 
   A pair of upright members  48  are welded to the cradle sides  36 , with a cross tube member  50  extending therebetween which also serves to retain the tote box  40  loaded into the cradle  34  when the cradle  34  is swung up to be inverted as described below. 
   The tote box  40  in the cradle  34  is also retained therein when the cradle  34  is inverted by a cross channel beam member  52  fixed at either end to the upper ends of the pair of angled reinforcing members  54  affixed to respective sides  26  of the hopper  16 . 
   A pair of angled linkage arms  56  are disposed straddling the outside of the hopper side walls  26 , each linkage arm  56  affixed at one end to an axle shaft  58  extending within the cross tube  50 . The other end of each angled linkage arm  56  has a pivot connection  60  to the frame  12 . 
   The cradle  34  is pivotally mounted to the hopper  16  by bearing assemblies  62  mounted to either hopper side wall  26  receiving axles  64  on the cradle  34  sidewalls. This mounts the cradle  34  to allow the cradle to be swung up within the hopper  16  in the same lengthwise direction as the tilting motion of the hopper  16 . 
   As shown in the drawings, the cradle  34  and hopper  16  are configured and located with respect to each other so that a substantial clearance space is defined between their respective side walls and bottom which allows for relative swinging movement of the cradle  34  within the hopper  16  and also provides space for receiving parts P without creating any interference to the swing. 
   The hopper  16  has a pair of belt idler spools  66  mounted at the left of the rear wall  28  (again, located at the bottom in FIG.  1 ). An electric drive motor  68  and reducer  70  drives a shaft  74  on which are mounted a pair of wind up reels  72  which have respective polyester belts  76  which extend around a respective idler spool  66 , beneath the hopper  16 , around a tube  78  and each terminating beneath a respective clamping plate  82  which is fastened to a respective fixed channel piece  80 . 
   A conventional belt slack detection mechanism  84  is associated with each belt  76 . 
   In operation, a tote box  40  loaded with loose parts is placed in the cradle  34 . 
   A receptacle, such as the perforated plating barrel  86  is shown moved into position forward of the apparatus  10  in  FIG. 1  as by operation of a drive  88  on a support dolly  90  of conventional design. 
   The belts  76  are wound up by operation of the motor  68  and reducer  70 , raising the hopper  16  up about the pivot  22 , the now inclined rear wall  28  and bottom wall  20  forming a collecting space as the hopper  16  swings to the intermediate position shown in FIG.  4 . 
   The cradle  34 , due to the constraining action of the linkage arms  56  is at the same time swung up to a greater extent, reaching a vertical orientation before the hopper  16  reaches a horizontal position as it is swung up, causing the parts P to be discharged out of the tote box  40  and collected in the rear collecting space defined by the now inclined rear wall  28  and the bottom plate  20  of the hopper  16 . 
   Upon continued wind up of the belts  76 , the hopper  16  is swung through a horizontal position to a downwardly inclined front end orientation shown in FIG.  5 . 
   The hopper  16  has a discharge guide  92  which is moved into an aligned opening  94  in the receptacle barrel  86 , and parts P are gravity discharged from the hopper  16  into the barrel  86 . 
   The cradle  34  is substantially inverted, causing the tote box  40  to fall against the cross tube member  50  and cross beam member  52 , causing the remaining parts P to be completely discharged into the hopper  16 , which funnels the same into the barrel  86 . 
   If parts P remain in the hopper  16  after being swung up, the operator can relower the hopper  16  to obtain complete clearing of the parts P. 
   The different degree of movement of the hopper  16  and cradle  34  and their separation precludes any chance that parts can become wedged between these components. 
   Only a single actuator is required such that the drive is relatively simple and reliable. The electric motor and belt drive could also be carried out with hydraulic actuators.