Patent Publication Number: US-6658997-B2

Title: Apparatus for producing waste compressed solid

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus for producing a waste compressed solid. 
     2. Description of the Related Art 
     As an apparatus for compressing and solidifying a waste such as a metal chip or the like, a structure disclosed in Japanese Patent Application Laid-Open No. 9-239593 is known. 
     The waste compressing and solidifying apparatus mentioned above is based on a main body frame, and comprises a hopper capable of receiving a waste in the main body frame. A large-scaled supply opening portion is provided in an upper side of the hopper, and a discharge port is provided in a bottom side of the hopper. Further, a compression box provided with a compression chamber capable of being communicated with the discharge port, and a compressing means for compressing and solidifying the waste fed the compression chamber under a sealed state are provided in the main body frame. In order to feed the waste from the hopper to the compression chamber, a feed screw conveyor is provided inside the hopper so as to be capable of rotating, and the feed screw conveyor is structured such as to extend to a portion near the compression chamber. 
     The waste supplied into the hopper is fed to the discharge port of the hopper due to a rotation of the feed screw conveyor, and is transferred to the compression chamber. Further, the waste is made into the compressed solid in the sealed state due to an operation of the compressing means. 
     SUMMARY OF THE INVENTION 
     A filament-like waste such as the metal chip often coils around a screw shaft due to the rotation of the feed screw conveyor. In this state, when the feed screw conveyor further rotates, a lump of the coiling waste gradually grows so as to stay near the discharge port and it is necessary to interrupt the operation. 
     The present invention provides an apparatus for continuously producing a waste compressed solid without the waste staying in a hopper. 
     An apparatus for producing a waste compressed solid according to a first aspect of the present invention comprises a hopper comprising an opening for receiving a waste in an upper side thereof and a discharge port in a bottom side, a feed screw conveyor for transferring the waste to the hopper to the discharge port, and a compression chamber connected to the discharge port of the hopper and comprising a compressing means. The waste received by the hopper is carried to a side of the discharge port of the hopper by the feed screw conveyor, and is fed to the compression chamber. Next, the waste in the compression chamber is compressed and solidified by moving a piston. Accordingly, it is possible to produce a waste compressed solid from the waste. A shaft of the feed screw conveyor is formed in a taper shape so as to become gradually narrow from a base end side toward a front-end side. Accordingly, when the lump of the waste is fed to the feed screw conveyor, a twist of the waste with the shaft is gradually loosened and the waste is easily removed by itself. 
     According to a second aspect of the present invention, the apparatus for producing the waste compressed solid as mentioned above further comprises a control means for controlling a driving direction of the feed screw conveyer so that the feed screw conveyor can be alternately driven in both directions comprising a forward direction and a backward direction. Since the lump of the waste coiling around the feed screw conveyor is removed by alternately driving the screw conveyor in the forward direction and the backward direction, it is possible to continuously compress and solidify the waste without interrupting the operation. 
     According to a third aspect of the present invention, the apparatus for producing the waste compressed solid as mentioned above further comprises draw screw conveyors comprising a pair of spiral-shaped draw blades in the hopper so as to cross to the feed screw conveyor and be symmetrical with respect to the feed screw conveyor, wherein the draw blades draw the waste to the hopper in a direction of the feed screw conveyor. The draw blades of the draw screw conveyors are formed in a spiral shape wound around in both sides of the feed screw conveyor, wherein directions of the respective draw blades are directed opposite to each other, and can draw the waste to the side of the discharge port from both sides when rotated. A draw motor control unit is controlled so as to stop the draw screw conveyors or reverse rotate the draw screw conveyors at a time of rotating the feed screw conveyor in an opposite direction. Accordingly, it is possible to prevent the waste from clogging near the discharge port and it is possible to continuously compress and solidify the waste. 
     According to a fourth aspect of the present invention, the apparatus for producing the waste compressed solid as mentioned above further comprises first and second screw conveyors comprising spiral-shaped draw blades substantially vertical to the feed screw conveyor and substantially in symmetrical therewith, and first and second draw motors driving them respectively. It is possible to draw the waste to the side of the discharge port from both sides by driving a pair of draw screw conveyors by the respective draw motors. Further, according to this structure, since the shafts of the respective draw screw conveyors do not hang over the shaft of the feed screw conveyor, it is possible to prevent the lump of the waste coiling around the shaft of the feed screw conveyor from being caught on the respective draw screw conveyors. Further, the respective motor control units are controlled so that rotational speeds of the first and second draw screw conveyors are different from each other. A compelling force in a twisting direction is applied to the drawn waste by applying a difference to the rotational speeds of the draw screw conveyors, whereby it is possible to prevent the waste from floating up. 
     According to a fifth aspect of the present invention, the structure of the apparatus for producing the waste compressed solid is made as mentioned above, and further, a feed blade of the feed screw conveyor has substantially no length in a base portion of the feed screw conveyor and become gradually longer toward a direction of an end portion. Even when the waste received by the hopper is fine and much, it is hard that the waste is caught on the feed blade. 
     According to a sixth aspect of the present invention, the structure of the apparatus for producing the waste compressed solid is made as mentioned above, and further, a pitch of the feed blade in the feed screw conveyor becomes gradually narrower toward the side of the discharge port of the hopper, and gradually wider toward the side of the discharge port near the discharge port of the hopper. According to this structure, it is possible to slow the feed speed of the waste in the side of the discharge port rather than the side of the base end of the feed screw conveyor, and it is possible to make it faster near the discharge port. According to this structure, it becomes hard that the lump of the waste is caught on near the discharge port, and it is possible to continuously operate the apparatus for producing the waste compressed solid. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view showing an apparatus for producing a waste compressed solid according to a first embodiment of the present invention; 
     FIG. 2 is a plan view showing the apparatus for producing the waste compressed solid according to the first embodiment of the present invention; 
     FIG. 3 is a perspective view showing an inner portion of a hopper in the apparatus for producing the waste compressed solid according to the first embodiment of the present invention; 
     FIG. 4 is a plan view showing an apparatus for producing a waste compressed solid according to a second embodiment of the present invention; 
     FIG. 5 is a perspective view showing an inner portion of a hopper in the apparatus for producing the waste compressed solid according to the second embodiment of the present invention; 
     FIG. 6 is a front elevational view of a feed screw conveyor according to the present invention; 
     FIG. 7 is a view of the feed screw conveyor according to the present invention as seen along a line V—V in FIG. 6; and 
     FIG. 8 is a front elevational view of a modified embodiment of a feed screw conveyor according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A description will be given below of a structure of an apparatus for producing a waste compressed solid according to a first embodiment of the present invention with reference to FIGS. 1 to  3 . 
     A waste compressed solid producing apparatus  1  according to the first embodiment of the present invention corresponds to an apparatus for producing a waste compressed solid by solidifying the waste such as a metal chip or the like, and is based on a main body frame  3 . The main body frame  3  comprises a supporting frame  5  extending in a lateral direction in FIGS. 1 and 2, and a box-like frame  7  standing on a right side portion of the supporting frame  5 . 
     A hopper  9  receiving a waste is provided in a left side of the box-like frame  7 , and in order to collect the waste in a bottom portion of the hopper  9 , the hopper  9  is formed in a V-shaped cross sectional shape. An opening  11  is provided in an upper side in FIG. 1 of the hopper  9 , and a discharge port  13  is provided in a lower side of the hopper  9 . One end of a connection pipe  15  is integrally provided in the discharge port  13  in the hopper  9  so as to be communicated therewith. 
     An inclined feed groove  17  is formed in an inner side of the hopper  9 , and a feed screw conveyor  19  feeding the waste in the hopper  9  to the discharge port  13  is provided in the hopper  9 . The feed screw conveyor  19  is provided with a rotatable feed screw shaft  21  disposed in the feed groove  17 , a feed blade  23  integrally formed in a spiral manner so as to wind around the feed screw shaft  21 , a feed motor  25  disposed at a suitable position in a right portion of the hopper  9  and connected to the feed screw shaft  21  in an interlocking manner, and a switching means  111  for alternately switching a rotational direction of the feed motor. 
     The feed blade  23  of the feed screw conveyor  19  has substantially no length around a base portion of the feed screw conveyor  19  and has a length gradually longer toward the side of the discharge port  13  of the hopper  9 , as shown in FIG.  7 . Accordingly, even if the waste received by the hopper  9  is fine and much, it becomes hard that the waste is caught on the feed blade  23 . The feed screw shaft  21  is formed in a taper shape so as to be gradually narrower toward the side of the discharge port  13  of the hopper  9  from the side of the base end. Accordingly, when the lump of the waste is fed to the feed screw conveyor  19 , a twist of the waste with the feed screw shaft  21  is gradually loosened, and the waste is easily removed. A pitch of the feed blade  23  in the feed screw conveyor  19  has a uniform interval from the side of the base end toward the side of the discharge port  13  of the hopper  9 , however, as shown in FIG. 8, becomes gradually narrower toward the side of the discharge port  13  of the hopper  9 , and further can be inversely made wider near the discharge port  13 . According to the structure mentioned above, it is possible to make the feed speed of the waste slower in the side of the discharge port  13  than the side of the base end and make it faster near the discharge port  13 . According to the structure mentioned above, it is hard that the lump of the waste clogs near the discharge port  13  and it is possible to continuously operate the waste compressed solid producing apparatus  1 . 
     The switching means  111  for alternately switching the rotational direction of the feed motor  25  comprises a feed motor control unit  113 , a first timer  115 , a second timer  117  and a third timer  119  which are connected to the feed motor control unit  113 , and is electrically connected to the feed motor  25 . The first timer  115  controls a time for rotating the feed screw conveyor  19  in a feed direction (a feeding rotation time), and the second timer  117  controls a time for rotating in an opposite direction thereto (an opposite feeding rotation time). By alternately switching the rotational direction of the feed motor  25  by using these timers, the lump of the waste going to coil around the screw shaft  21  is removed, and it is possible to continuously operate the waste compressed solid producing apparatus  1 . The third timer  119  controls a total rotational time of the feed screw conveyor  19  so as to adjust the waste fed to the compression chamber  47  to a proper amount. 
     A draw groove  27  passing through the discharge port  13  Ls formed in a bottom portion of the hopper  9 , and a draw screw conveyor  29  drawing the waste in the hopper  9  is provided in the hopper  9 . The draw screw conveyor  29  is provided with a draw screw shaft  31  capable of rotating in forward and backward directions in the draw groove  27 , a forward wound draw blade  33  integrally formed in a spiral manner so as to coil around an upper side in FIG. 2 of the draw screw shaft  31  in a forward direction, a backward wound draw blade  35  integrally formed in a spiral manner so as to coil around a lower side in FIG. 2 of the draw screw shaft  31  in a backward direction, a draw motor  37  provided at a suitable position of a rear portion of the box-like frame  7  and connected to the draw screw shaft  31  in an interlocking manner, and a draw motor control unit  123 . The draw blades  33  and  35  in the draw screw conveyor  29  are significantly larger than the feed blade  23  in the feed screw conveyor  19 . 
     As shown in FIG. 1, a compression box  43  is provided in a left side portion in FIG. 1 of the supporting frame  5 , and this compression box  43  is provided with a compression chamber  47  having a circular cross sectional shape. A supply port  49  with which another end of the connection pipe  15  is communicated is formed in an upper portion in FIG. 1 of the compression box  43 . An opening portion  51  is provided in a left side in FIG. 1 of the compression box  43  and a left edge in FIG. 1 of the supply port  49  has a sharp edge. 
     A circular piston  65  for compressing and solidifying the waste is provided with the compression chamber  41 , and the piston  65  can move in a lateral direction in FIG.  1 . In order to move the piston  65  In a lateral direction, a compression cylinder  69  provided with a movable rod  67  capable of moving in a lateral direction is provided in the supporting frame  5 , and the piston  65  is connected to a front end portion of the movable rod  67  so as to be detachable. The piston  65  has an operation of cutting the waste in cooperation with the sharp edge of the supply port  49  in addition to an operation of compressing the waste. 
     Next, a description will be given of a method of producing the waste compressed solid by the apparatus mentioned above. 
     At first, the waste such as the metal chip or the like is received by the hopper  9  from the opening  11 . 
     The feed motor  25  is connected to the feed screw conveyor  19 , and drives the screw shaft  21  so as to integrally rotate the feed blade  23 . The waste is carried to the discharge port  13  according to a motion of the feed blade  23 , and is fed to the compression chamber  47  through the supply port  49  in the compression box  39 . 
     A time for rotating the feed screw conveyor  19  in a feed direction is set by the first timer  115 . When the time set by the first timer  115  has passed, the feed screw conveyor  19  is backward rotated so as to rotate in an opposite feed direction. Accordingly, even in the case that the lump of the waste coils around the screw shaft  21  in a process that the feed screw conveyor L 9  rotates in the feed direction, the feed screw conveyor  19  rotates in the opposite feed direction, whereby there is generated an effect that the lump of the waste is dissembled. A time for which the feed screw conveyor  19  rotates in the opposite feed direction is set by the second timer  117 . 
     The feed screw conveyor alternately rotates in the feed direction and the opposite feed direction on the basis of the set of the first timer  115  and the second timer  117 , and this operation is repeated. Accordingly, it is possible to prevent the operation that the lump of the waste is dissembled from being prevented by the new waste being drawn, whereby a continuous operation can be performed. A time for which the operation is repeated is controlled by the third timer  119  setting the total rotational time. The set time of the first timer  115 , the second timer  117  and the third timer  119  are previously set in an optimum manner in correspondence to a characteristic of the waste. 
     The draw motor  37  drives the draw screw shaft  31  when the feed screw conveyor  19  rotates in the feed direction, whereby the forward wound draw blade  33  and the backward wound draw blade  35  of the draw screw conveyor  29  integrally rotate therewith so as to draw the waste from both sides to the side of the feed screw conveyor  19 . Accordingly, the waste in the hopper  11  is effectively fed to the feed screw conveyor  19 . 
     The rotational direction of the draw screw conveyor  29  is controlled by the draw motor control unit  123  in correspondence to the rotational direction of the feed screw conveyor  19 . When the feed screw conveyor  19  rotates in the feed direction, the draw screw conveyor  29  rotates in a direction of drawing the waste to a center side (a draw direction) and when the feed screw conveyor  19  rotates in an opposite feed direction, the draw screw conveyor  29  stops. It is possible to control so that when the feed screw conveyor  19  rotates in the opposite feed direction, the draw screw conveyor  29  rotates in an opposite direction (an opposite draw direction) to the direction of drawing the waste to the center side. Due to the operation of the draw screw conveyor  29  in cooperation with the feed screw conveyor  19  as mentioned above, it is possible to prevent the waste from clogging near the discharge port  13 . 
     When the total rotational time set in the third timer  119  expires, the feed motor  25  is controlled by the feed motor control unit  113 , and the rotation of the feed screw conveyor  19  is stopped. At the same time, the draw motor  37  is controlled by the draw motor control unit  123  and the rotation of the draw screw conveyor  29  is stopped. Further, the compression cylinder  69  operates, so that the piston  65  moves in a left direction in FIG.  1 . The waste running over upward from the supply port  49  is cut on the basis of a cooperation between a left edge portion of the piston  65  and the blade portion at a time when the left edge portion of the piston  65  passes through the sharp edge of the supply port  49 . By further moving the piston  65  in the left direction in FIG. 1 sequentially, the waste in the compression chamber  47  is compressed and solidified. 
     After the compression of the waste is finished, a take-out port  53  of the compression chamber  47  is opened. Further, by moving the piston  65  in the left direction in FIG. 1 due to the operation of the compression cylinder  69 , the waste is extruded in the left direction. Accordingly, it is possible to take out the waste compressed solid. 
     The process mentioned above is continuously executed in a repeated manner. Accordingly, it is possible to continuously produce the waste compressed solid from the waste. 
     Next, a description will be given of a second embodiment according to the present invention with reference to FIGS. 4 and 5. In these drawings, the same reference numerals are attached to the same elements as those in FIGS. 1 to  3 . A description will be given only of portions, which are different from the first embodiment, and a description of the portion having the coinciding structures will be omitted. 
     A waste compressed solid producing apparatus  10  according to the present embodiment is provided with a first draw screw conveyor  30   a  having a spiral-shaped draw blade and a second draw screw conveyor  30   b  in such a manner as to be substantially vertical to the feed screw conveyor  19  and be in symmetrical with each other. Further, there are provided a first draw motor  38   a  and a second draw motor  38   b  which respectively drive them, and a draw motor control unit  125  controlling rotations thereof. 
     The draw motor control unit  125  is electrically connected to the first and second draw motors  38   a  and  38   b  so as to control a rotational direction and a rotational speed of the first and second draw screw conveyor  30   a  and  30   b . When the feed screw conveyor  19  rotates in the feed direction, the draw motors  38   a  and  38   b  are rotated in a direction in which the draw screw conveyors  30   a  and  30   b  draw the waste to the center side (a draw direction). Accordingly, the waste in the hopper  11  can be efficiently fed to the feed screw conveyor  19 , and since the respective draw screw shafts  32   a  and  32   b  do not exist immediately above the feed screw shaft  21 , it is possible to prevent the lump of the waste coiling around the feed screw shaft  21  from being caught on the respective draw screw shafts  32   a  and  32   b.    
     In this case, the first draw motor  38   a  and the second draw motor  38   b  are controlled by the draw motor control unit  125  so that the rotational speed of the first draw screw conveyor  30   a  is different from the rotational speed of the second draw screw conveyor  30   b . Since the rotational speeds of the draw screw conveyors  30   a  and  30   b  are different, a compelling force in a twisting direction is applied to the drawn waste, so that it is possible to prevent the waste from floating up. Accordingly, it is possible to efficiently draw the waste to the feed screw conveyor  19 . 
     When the feed screw conveyor  19  rotates in the opposite feed direction, the draw motors  38   a  and  38   b  are controlled so as to stop the draw motors  38   a  and  38   b  or rotate the screw conveyors  30   a  and  30   b  in the opposite draw direction. Due to the operation of the draw screw conveyors  30   a  and  30   b  in cooperation with the feed screw conveyor  19  as mentioned above, it is possible to prevent the waste from clogging near the discharge port  13 . 
     According to the second embodiment of the present invention, in addition to the effects of the first embodiment mentioned above, it is possible to prevent the lump of the waste coiling around the feed screw shaft  21  from being caught on the first and second draw screw conveyors  68   a  and  68   b . Further, since the rotational speeds of the first and second draw screw conveyors  68   a  and  68   b  are different, it is possible to prevent the waste from floating up and it is possible to more efficiently draw the waste to the feed screw conveyor  20 . Accordingly, it is possible to continuously operate the apparatus without interrupting the production of the compressed solid, and an efficiency of the producing operation can be improved.