Abstract:
A high production nutcracking apparatus having a hood pivotally mounted to the machine frame to protectively cover the operating components, and so that the hood is pivotable between a closed position and a raised or open position which gives the operator of the machine access to the interior components. The hood is raised by a computer controlled pneumatic cylinder which is programmed to protect the operator from the risk of the hood falling from the raised or open position to the closed position.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a high speed nutcracking apparatus having a pivotally mounted hood for protectively covering the operating components of the machine.  
         [0002]     U.S. Pat. Nos. 4,332,827; 5,623,867; 6,205,915; 6,270,824; 6,584,890, 6,588,328; and 6,772,680 all disclose a high speed nutcracking apparatus which includes a rotatable turret which mounts a plurality of cracking units arranged about its periphery, with each cracking unit having an opening adapted to receive an individual nut from a feed conveyor which comprises a plurality of nut transport elements mounted in succession on a feed chain. Each of the nut transport elements includes an upwardly open traverse receptacle for holding an individual nut, and each cracking unit on the turret has an anvil which is moved axially into the receptacle at a pick up point so that the nut is engaged between the anvil and a crack die on the other side of the opening.  
         [0003]     In operation, the feed conveyor moves tangentially past the rotating turret so that the anvils of the cracking units enter the receptacles of respective nut transport elements at the pick up point and engage and pick up the nut. After the cracking unit and engaged nut have moved away from the pick up point and reach a cracking location, the crack die of the cracking unit is impacted by a shuttle so that the crack die applies an impact to the nut to crack the shell.  
         [0004]     To protectively cover the rotating turret, it has been conventional to pivotally mount a hood along the upper rear edge of the frame of the apparatus, and so that the hood is pivotable between a closed position covering the turret and a raised or open position which gives the operator of the machine access to the interior components for maintenance and cleaning. In order to provide adequate protection from the rapidly rotating turret, the hood has heretofore been fabricated from a sheet metal material such as stainless steel. This in turn results in the hood having significant weight, and it has been difficult for the operator to lift and lower the hood.  
         [0005]     It is accordingly an object of the present invention to provide a nutcracking apparatus of the described type which includes a pneumatic system for lifting and lowering the hood, while avoiding the risk of injury to the operator.  
       SUMMARY OF THE INVENTION  
       [0006]     The above and other objects and advantages of the invention are achieved by the provision of a high production nutcracking apparatus of the described type which includes a pneumatic system for selectively pivoting the hood between the open and closed positions, and which includes a pneumatic cylinder connected between the machine frame and the hood. A first port is provided in the pneumatic cylinder on one side of the piston and a second port is provided on the other side of the piston. Also, a first adjustable bleed valve is connected at the first port, and a second adjustable bleed valve is connected at the second port. A control valve means is provided for selectively introducing pressurized air into a first air line which leads to the first port via the first bleed valve, or into a second air line which leads to the second port via the second bleed valve.  
         [0007]     In operation, pressurized air can be delivered to the first port through the first air line while venting the cylinder through the second line and the second bleed valve, or air can be delivered to the second port through the second air line while venting the cylinder through the first air line and the first bleed valve.  
         [0008]     The above construction permits the hood to be both opened and closed in a controlled and thus safe manner.  
         [0009]     As a further aspect of the invention, a computer controller is provided which is programmed so as to control the operation of the pneumatic pivoting system to insure that the pneumatic system operates in a safe manner. Specifically, the computer controller can be programmed to operate the system to guard against an injury to the operator during the closing operation. For example, with the hood open and upon the hood close switch being pressed, the computer can be programmed to momentarily energize a control valve to insure that the pneumatic cylinder is charged with air tending to open the hood, before air is delivered to the side of the piston for closing the hood. This action avoids the possibility of the hood rapidly falling to the closed position in the event that the hood has been manually opened and there is no significant charge of air on the hood opening side of the piston while the hood is in the open position.  
         [0010]     The computer controller can also be programmed to reduce the likelihood that the operator&#39;s hand could be caught in the “pinch point” provided along the front edge of machine frame. For this purpose, the computer controller may be programmed to terminate the delivery of pressurized air to the closing side of the piston after the hood has been moved to a midpoint of its travel to the closed position, so that continued movement results solely from gravity. The relevant bleed valve prevents the rapid evacuation of the cylinder and thus the hood continues its closing movement at a controlled rate. Also, the absence of pressurized air on the closing side of the piston avoids the possibility that the forward edge of the hood could be forcefully pressed against a hand of the operator which might be inadvertently placed in the “pinch point”. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:  
         [0012]      FIG. 1  is a perspective view of a high production nutcracking apparatus which embodies the features of the present invention;  
         [0013]      FIG. 2  is a sectional side elevation view of the apparatus taken along the line  2 - 2  of  FIG. 1 ;  
         [0014]      FIG. 3A  is a fragmentary sectional side elevation view corresponding to  FIG. 2  and showing the hood lifting sequence;  
         [0015]      FIG. 3B  is a view similar to  FIG. 3A  and showing the hood closing sequence;  
         [0016]      FIG. 3C  is a view similar to  FIG. 3A  and showing the hood in the fully closed position; and  
         [0017]      FIG. 4  is a fragmentary sectional view of the bleed valve at the upper end of the pneumatic cylinder of the apparatus of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]     The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which a preferred, but not necessarily all embodiments of the invention is shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiment set forth herein. Rather, the illustrated embodiment is provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.  
         [0019]     Referring more particularly to the drawings,  FIGS. 1-2  illustrate a high production nutcracking apparatus  10  which embodies the features of the present invention. As will become apparent, many of the components of the present apparatus conform to the corresponding components of the apparatus shown and described in the prior U.S. patents which are listed above under the heading Background of the Invention. The disclosures of these prior patents are expressly incorporated herein, and reference may be had to these prior patents for a more detailed description of the common components.  
         [0020]     The apparatus comprises a frame which defines a box-like cabinet  12  which includes a pair of front doors  14 , and a rear side  15 . A hood  16  is pivotally mounted to the top of the cabinet and so as to be pivotable between a closed position (shown in solid lines in  FIGS. 2 and 3 C) and an open position (shown in broken lines in  FIG. 2  and in  FIG. 3A ). Also, the upper edge of the cabinet  12  supports a pair of bearing blocks  17  (only one being seen in  FIG. 1 ) which rotatably mount a central shaft  18  which defines a horizontal central axis. The hood  16  is mounted for pivotal movement about an axis  19  which is parallel to and spaced rearwardly from the central axis.  
         [0021]     A cracking assembly in the form of a turret  20  is fixedly mounted to the shaft  18  so as to be rotatable with the shaft about the central axis. The turret  20  comprises a plurality of elongate cracking units  22  which are circularly arranged about the shaft  18  and supported by radially disposed plates (not shown). There are sixteen cracking units  22  in the illustrated embodiment and the units extend generally parallel to each other and to the central axis.  
         [0022]     The cracking units  22  each define an opening for receiving the nuts, and the openings of the units are aligned with an annular opening in the periphery of the turret as best seen in  FIG. 2 . The structure and function of the cracking units and annular opening are otherwise fully disclosed in the prior patents listed above and which are incorporated by reference.  
         [0023]     The apparatus of the present invention further includes means for advancing and delivering a plurality of nuts individually in succession along a path of travel to the rotating turret  20 . This nut delivering means includes a hopper  26  for storing a relatively large quantity of nuts to be cracked, and which is fixed to the rear side  15  of the cabinet  12 . An endless feed conveyor  28  is provided which includes a feed chain which extends through the hopper and conveys the nuts to a delivery point adjacent the bottom dead center position of the turret  20 , all as further described in the prior patents which are incorporated by reference.  
         [0024]     The turret  20  is rotatably driven by a motor and chain drive  30  ( FIG. 2 ) and operates so that each cracking unit  22  picks up a nut from the conveyor  28  at the bottom dead center position of the turret. With continued rotation of the turret, the nut is stressed at about the 11 o&#39;clock position of the turret when viewed as seen in  FIG. 3  and with the turret rotating in the counterclockwise direction. Immediately thereafter, the nut is cracked, and the cracked nut falls into a delivery chute  32  which exits on the side of the cabinet.  
         [0025]     In accordance with the present invention, a pneumatic system is provided for selectively pivoting the hood  16  between the open and closed positions about a pivotal axis  19 . This pneumatic system includes a pneumatic cylinder  34  which has a lower end  35  connected to a bottom plate  36  of the hopper  26  of the apparatus, and a piston rod  37  which is connected to a piston  38  slideably mounted within the cylinder and to the hood at a point offset from the pivotal axis  19 . As will be apparent from  FIGS. 3A-3C , movement of the piston  38  causes the hood  16  to pivot between its open and closed positions.  
         [0026]     The pneumatic cylinder  34  includes a first port  40  located above the piston, and which is connected to an air delivery line  41  via a bleed valve  42 . As seen in  FIG. 4 , the bleed valve  42  includes a threaded plug  43  by which the area of the air passage through the valve can be adjusted. Also, the bleed valve  42  preferably is of the type which permits the free flow of air in the delivery direction into the cylinder  34  while restricting the flow to an extent determined by the position of the threaded plug  43  in the opposite or venting direction. Such a bleed valve is sold by Legris under Model No. 7015-56-14.  
         [0027]     A second port  45  is located in the cylinder  34  below the piston  38 , and which is connected to an air delivery line  46  via a bleed valve  47 . The bleed-valve  47  corresponds to the structure of the bleed valve  42 .  
         [0028]     The lines  41  and  46  are respectively connected to two control valves  50 ,  51  as schematically illustrated in  FIGS. 3A-3C , and each control valve  50 ,  51  is connected to a source  52  of pressurized air via a regulator (not shown). Each valve  50 ,  51  has a solenoid which is controlled by a programmed computer controller  54 , and when energized by a signal from the computer controller  54 , the valve  50 ,  51  moves to an open position which permits free passage of the pressurized air to the associated line  41  and  46 , and when de-energized, the valve moves to a venting position.  
         [0029]     The operating sequence of the hood pivoting system is controlled by the programmed computer controller  54 , which includes a Hood Open switch  56  and a Hood Close switch  58 . The operating sequence for both opening and closing the hood are set forth in the following:  
         [0000]     The Hood Lifting Sequence  
         [0030]     When the hood  16  is in the closed position as seen in solid lines in  FIGS. 2 and 3 C, which is normally the case when the machine is operating, the valves  50 ,  51  are normally de-energized and thus both lines are vented to the atmosphere. Thus there is no pressure on either side of the piston  38  in the pneumatic cylinder  34 . To lift the hood, the Hood Open switch  56  is pressed which causes the control valve  50  to be energized to the position shown in  FIG. 3A  and so as to direct the pressurized air into the line  41 , through the bleed valve  42 , and into the cylinder  34  above the piston  38 . The resulting pressure causes the piston rod  37  to move downwardly. The valve  51  remains de-energized and open for venting the line  46 , and the bleed valve  47  below the piston  38  serves to control the rate of flow through the vent line  46 . Thus the rate of downward movement of the piston  38  is controlled as is the upward pivotal movement of the hood  16 . This rate of upward pivotal movement can be easily adjusted by turning the threaded plug  43  of the bleed valve  47  to either increase or decrease the size of the vent opening.  
         [0031]     The pressure in the line  41  is maintained while the hood  16  is in its open position and until the Hood Close switch  58  is pressed. While the pressure is maintained in the line  41 , the resulting pressure above the piston  38  prevents the hood from inadvertently falling during maintenance procedures which require the hood to be open.  
         [0000]     The Hood Lowering Sequence  
         [0032]     Upon pressing the Hood Close switch  58 , the valve  50  is momentarily energized by the computer controller  54 , such as for about 1.5 seconds, to hold the position shown in  FIG. 3A  and permit the pressurized air to continue to enter the line  41  and thereby insure that the cylinder is fully charged above the piston before closing movement begins. This function is redundant in normal operation since as noted above, the valve  50  is already in the energized position and it continues to deliver pressurized air to the air line  41  until the Hood Close switch  58  is pressed. However, if the hood  16  has been inadvertently manually raised from the closed to the open position, there will be little pressure above the piston  38  and the hood could rapidly fall to the closed position and possibly injure the operator. The fact that the controller  54  is programmed to initially pressurize the space above the piston, before the valve  51  is energized to start the downward movement of the hood, thus serves to insure that such a rapid closure will not occur, even when the hood has been manually lifted to the open position.  
         [0033]     After the momentary delay, the valve  50  is then de-energized so that it shifts to its venting position, and the valve  51  is moved to its energized position as shown in  FIG. 3B , such that the air is directed into the line  46  and into the cylinder  34  below the piston  38 . At the same time, the charge of air above the piston is vented through the bleed valve  42 , at a rate controlled by the setting of the threaded plug  43 .  
         [0034]     Preferably, the valve  51  is held in the energized position for a short period of time, such as about 8 seconds, and so that the hood  16  is caused to close to about two-thirds of its travel. After reaching that point, the air line valve  51  is de-energized by the controller  54 , which allows the hood to continue to close due to gravity, with the charge of air above the piston  38  venting at a controlled rate through the bleed off valve  42 . This sequence eliminates the possibility that the operator&#39;s hand could be caught in the “pinch point” along the forward edge of the hood, and with the forward edge being biased downwardly by pressurized air below the piston, as noted above.  
         [0035]     Many modifications and other embodiments of the invention set forth herein will come to mind to one skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing description and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.