Abstract:
An apparatus for recycling metal scraps includes a mold having an inner conversion cavity for converting the metal scraps, an inlet disposed in one longitudinal end thereof, and an outlet disposed in the other longitudinal ends thereof, the inlet and the outlet communicating with the cavity; a gate movably mounted near the outlet of the mold so as to open and close the outlet of the mold as the gate moves; a gate actuator moving the gate to an opening or closing position; a scrap feeder supplying the metal scraps into the cavity of the mold, a conversion plunger intruded into the cavity via the inlet of the mold and compacting the metal scraps to form a solid compact having a shape corresponding to the cavity; and a press actuator reciprocating the conversion plunger between inside and outside of the mold so as to provide a conversion pressure.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority from Korean Patent Application Number 10-2009-0056414, filed on Jun. 24, 2009, the entire contents of which are fully incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus for recycling metal scraps, and more particularly, to an apparatus for recycling metal scraps that can convert the scraps, produced in the machining of a metal material, into a solid compact having a high specific gravity, so that the scraps are not lost due to oxidation when they are being melt, and convert the scraps without using cutting fluid, thereby reducing the creation of pollutants. 
     2. Description of Related Art 
     The process of cutting a metal material produces various types of scraps, such as granular or spiral scraps. The scraps take a sizable amount, which is typically 5 to 10% of the weight of the metal material subjected to the cutting. Therefore, various methods are used to collect and recycle the scraps. For example, as for scraps produced in the cutting of a cast material, the scraps are melted again together with a molten source metal in a melting furnace, so that it can be reused as a raw material in the casting. 
     However, the collected scraps, which are input into the melting furnace, have a significantly small specific gravity relative to the molten source metal, so that the majority of scraps input into the melting furnace suspends on the surface of the molten metal without immersing into the molten metal while it is being melted. Thus, a great amount of the scraps is oxidized in the melting process by contact with air. Since the oxidized scraps lost their own properties of a source metal, they are screened and disposed. Thus, only 50% to 60% of the input scraps can be reused, thereby raising a problem such as a very low source recovery rate (recycling rate). 
     To solve this problem, a method had been proposed, in which the molten metal is rotated to make the input scraps immerse more easily in the molten metal, thereby reducing the loss of scraps due to oxidation. However, in order to use this method, special equipments for rotating the molten metal are required and a melting furnace should be separately fabricated to suit to the equipment, so that mounting costs for a melting apparatus increase greatly. Furthermore, the rotation of the molten metal results in a reduction in the lifetime of the melting furnace and an increase in the cost of energy that is consumed in the process. 
     Further, while there had been proposed a method that the suspended scraps on the surface of the molten metal are forcedly pushed and immersed in the molten metal, a problem also arises in that special equipments for immersing the scraps are required and an installation cost for a melting apparatus increases greatly, and for small, light scraps, it is difficult to immerse them in the molten metal, so that the effects of reducing losses of the scraps due to oxidation are degraded. 
     Meanwhile, the recovered scraps are impregnated with cutting fluid that is used for cutting a metal material. However, if the scraps impregnated with the cutting fluid are melted as they are, an environmental contamination arises due to combustion of the cutting fluid. To prevent this, according to the related art, a separate washing process for removing the cutting fluid was required. However, because of a large surface area of the scraps, a great amount of cost and time was taken in the washing process, resulting in a further deterioration in a recovery efficiency of the scraps. 
     The information disclosed in this Background of the Invention section is only for the enhancement of understanding of the background of the invention, and should not be taken as an acknowledgment or any form of suggestion that this information forms a prior art that would already be known to a person skilled in the art. 
     BRIEF SUMMARY OF THE INVENTION 
     Various aspects of the present invention provide an apparatus for recycling metal scraps which can compress the metal scraps to increase the specific gravity while removing cutting oil, thereby preventing oxidation of the scraps that occurs due to suspension on the surface of molten metal when they are being melted, and reducing the creation of pollutants due to combustion of the cutting oil. 
     In an aspect of the present invention, the apparatus for recycling metal scraps includes: a mold having an inner conversion cavity for converting the metal scraps, an inlet disposed in one longitudinal end thereof, and an outlet disposed in the other longitudinal ends thereof, the inlet and the outlet communicating with the cavity; a gate movably mounted near the outlet of the mold so as to open and close the outlet of the mold as the gate moves; a gate actuator moving the gate to an opening or closing position; a scrap feeder supplying the metal scraps into the cavity of the mold, a conversion plunger intruded into the cavity via the inlet of the mold and compacting the metal scraps to form a solid compact having a shape corresponding to the cavity; and a press actuator reciprocating the conversion plunger between inside and outside of the mold so as to provide a conversion pressure. 
     In an exemplary embodiment, the apparatus may further include a mold housing fixedly enclosing the mold, in which the mold is provided with a plurality of mold blocks, which is mounted in the mold housing adjacent to each other, thereby to define the cavity. 
     In an exemplary embodiment, the apparatus may further include a guide pad provided adjacent to the inlet of the mold and having a guide groove guiding the conversion plunger toward the cavity of the mold, and an inlet portion opened in an upper portion of the guide groove. 
     In an exemplary embodiment, the scrap feeder may include a hopper, which has an outlet facing the inlet portion of the guide pad, and a loader for transporting the scraps, received in the hopper, to the inlet portion of the guide pad. 
     In an exemplary embodiment, the loader may include a transporting screw provided in a vertical direction in the hopper, a driving mechanism rotating the transporting screw, and a transporting guide provided outside the transporting screw, in which the transporting guide has open scrap inlet and outlet in the upper and lower portion thereof, and a tubular passage between the scrap inlet and outlet. 
     In an exemplary embodiment, the apparatus may also include an auxiliary loader having a hydraulic cylinder and a push rod, in which the push rod is caused to vertically reciprocate in the hopper by the hydraulic cylinder, thereby transporting the metal scraps towards the outlet of the hopper. 
     In an exemplary embodiment, the gate may include an opening connected to and disconnected from the inlet of the mold as it moves. 
     In an exemplary embodiment, the apparatus may also include a guide housing mounted adjacent to a front end of the guide pad, and having therein a guide that movably supports the conversion plunger. 
     In an exemplary embodiment, the apparatus may also include an oil pan mounted on the lower side of the mold and collecting cutting oil discharged outside when the metal scraps are compressed. 
     According to exemplary embodiments of the present invention as set forth above, the following effects are provided. 
     (1) The metal scraps that were produced during processing a metal material are compressed to form a solid compact having a high specific gravity such that the metal scraps are immersed in the molten metal without suspending on the surface of molten metal when they are injected into the molten metal, and also to reduce cutting oil impregnated therein, thereby preventing occurrence of oxidation loss during melting of the metal scraps and thus increasing the recovery rate of the metal scraps and reducing the occurrence of pollutants due to combustion of cutting oil. 
     (2) The mold is provided with divided mold blocks, which reduce stress applied to the mold upon receiving a molding pressure, so that metal scraps can be compact-converted with a higher molding pressure into a compact having a higher specific gravity in a short time, thereby improving productivity, extending and reducing the lifetime and weight of mold, and providing smooth discharging of the cutting oil and therefore reducing the content of the cutting oil impregnated in the compact furthermore. 
     (3) The metal scraps received in the hopper are intruded by a certain amount into the mold without congestion by means of the transporting guide and transporting screw of the loader, thereby providing a smooth, precise feeding of the metal scraps and thus improving the productivity of the apparatus. 
     The methods and apparatuses of the present invention have other features and advantages which will be apparent from, or are set forth in more detail in the accompanying drawings, which are incorporated herein, and in the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front elevation view showing an apparatus for recycling metal scraps according to an exemplary embodiment of the invention; 
         FIG. 2  is a top plan view of the apparatus for recycling metal scraps shown in  FIG. 1 ; 
         FIG. 3  is a side elevation view of the apparatus for recycling metal scraps shown in  FIG. 1 ; and 
         FIG. 4  is an enlargement view of the converter of the apparatus for recycling metal scraps shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments that may be included within the spirit and scope of the invention as defined by the appended claims. 
       FIG. 1  is a front elevation view showing an apparatus for recycling metal scraps according to an exemplary embodiment of the invention,  FIG. 2  is a top plan view of the apparatus for recycling metal scraps shown in  FIG. 1 ,  FIG. 3  is a side elevation view of the apparatus for recycling metal scraps shown in  FIG. 1 , and  FIG. 4  is an enlargement view of the converter of the apparatus for recycling metal scraps shown in  FIG. 1 . 
     As shown in the figures, the apparatus for recycling metal scraps includes a base  101 , a front plate  103  provided in front of the base  101 , a rear plate  104  provided in the rear of the base  101 , a plurality of tie bars  109  connected between the front and rear plates  103  and  104 , a converter  110  provided on the front plate  103 , a press  150  provided on the rear plate  104 , a scrap feeder  170  provided around the converter  110 , and a conveyor  190  configured to transport converted materials. 
     The base  101  is configured to provide a horizontal mounting plane, in which leveling bolts  102  are provided in certain intervals. 
     The front plate  103  and the rear plate  104  support the converter  110  and the press  150 , respectively, and are fastened with each other by the tie bars  109 , so that they can maintain the position when a conversion pressure is applied thereto. The front plate  103  has an outlet  105  that forms a discharge passage of compacts that are produced by compression in the converter  110 . The outlet  105  can be flared in the discharge direction in order to facilitate discharge of the converted materials. 
     The converter  110  receives the scraps supplied thereto, and produces converted materials in the form of single solid compacts from the scraps by compressing the scraps under the pressure applied from the press  150 . In the converter  110 , a gate  111  is connected to the inner side of the front plate  103  such that it can move up and down, and a gate actuator  113  is provided to drive the gate  111  up and down. Below the gate  111 , a bracket  114  is mounted on the front plate  103 , extending in the horizontal direction. A mold housing  115  is connected to the gate  111  and is fixedly provided on the upper portion of the bracket  114 , and a mold  116  is provided inside the mold housing  115 . A guide pad  117  is connected to the mold  116  and fixedly provided on the upper portion of the bracket  114 . A guide housing  118  is connected to the guide pad  117  and is fixedly provided on the upper portion of the bracket  114 . 
     The gate  111  blocks and communicates the inside of the mold  116  from and with the outlet  105  of the front plate  103 . In the blocking position, the gate  111  cooperates with the mold  116  to define a cavity  119  where metal scraps are converted. In the open position, the inside of the mold  116  communicates with the outlet  105  of the front plate  103  such that a compressed compact can be discharged from the mold  116  through the outlet  105 . For this, both the right and left sides of the gate  111  are coupled with the front plate  103  in such a fashion that the gate  111  can slide up and down. The gate  111  also has an opening  112  in the upper central portion thereof. The opening  112  of the gate  111  can have a guide section in one side thereof that faces the mold  116 , the guide section flared toward the mold  116  to facilitate the discharge of the compact. 
     The gate actuator  113  serves to move the gate  111  up and down so that the gate  111  allows the inside of the mold  116  to communicate with the outlet  105  in one position (e.g., a raised position) but blocks the inside of the mold  116  from the outlet  105  in the other position (e.g., a lowered position). The gate actuator  113  can be embodied as an actuator that performs a linearly-reciprocating motion, such as an electromotive actuator using a motor or an electromagnet. In this embodiment, the gate actuator is illustrated as a hydraulic cylinder that is coupled with a fixing member  120  on the upper portion of the front plate  103  and has a rod coupled with the upper portion of the gate  111 . 
     The bracket  114  provides a horizontal mounting plane where the mold guide  115 , the guide pad  117  and the guide housing  118  can be collinearly arranged. The bracket  114  has a passage  124  in one end thereof, which is coupled with the front plate  103 , such that the gate  111  can move up and down through the passage  124 . 
     The mold housing  115  encloses the mold  116  therein, and serves to maintain the shape of the mold  116  while resisting against pressure that is applied when the mold  16  is operating. The mold housing  115  defines therein a mold-receiving portion  125 , a seating portion  123  in one end of the mold-receiving portion  125 , and a plurality of bolt holes  126  formed radially in the seating portion  123 , the bolt holes  126  spaced apart from each other at predetermined intervals. 
     The mold  116  is configured to convert metal scraps, which are supplied into the mold  116 , into a solid compact. The mold  116  is in the form of a sleeve that has an open entrance in one longitudinal end thereof and an open exit in the other longitudinal end thereof, and also has an inclined portion  128  that expands in diameter to facilitate introduction of the scraps, which are subject to conversion. 
     Although the mold  116  can be formed as one body, it is preferred that the mold  116  be formed of a plurality of separate mold blocks  121 , as shown in the upper right part of  FIG. 4 . Each of the mold blocks  121  is in the form of an arc, such that they can define therein a cavity  119  having a circular cross section when fitted inside the mold housing  115 . A flange  122  is provided on one end of each mold block  121 , which forms the entrance of the mold  116 . A plurality of the flanges  122  is intruded into the seating portion  123  of the mold housing  115  to support the conversion pressure. A plurality of coupling holes  127 , corresponding to the bolt holes  126 , are formed in the flanges  122 , such that the individual mold blocks  121  are coupled with the mold housing  115  via bolts. 
     The guide pad  117  is configured to receive scraps supplied from the scrap feeder  170  so that the received scraps are input into the mold  116  by a conversion plunger  151  of the press  150 . The guide pad  117  has a guide groove  129 , which guides the movement of the conversion plunger  151  in the same direction as the cavity  119  of the mold  116  does, and an open loading portion  130  above the guide groove  129 , so that the scraps can be supplied into the loading portion  130 . Preferably, the loading portion  130  can have a shape that expands upward. 
     The guide housing  118  is configured to guide the movement of the conversion plunger  151  while supporting the same. The guide housing  118  has a guide  131  mounted therein such that the conversion plunger  151  can be intruded into the guide  131  in the same direction as in the guide groove  129  of the guide pad  117 . 
     In addition, an oil pan  132  is provided below the converter  110 , and collects cutting fluid that is discharged when the scraps are being compressed. 
     The press  150  includes a press actuator  152 , which is fixed to the rear plate  104  and is arranged in the horizontal direction, a push rod  153 , which is reciprocally moved by the press actuator  152  to and from the converter  110 , and a conversion plunger  151 , which is coupled to one end of the push rod  153  to force the scraps input into the converter  110 . 
     In this embodiment, the press actuator  152 , which provides the scraps-converting pressure and force to the conversion plunger  151 , is illustrated and described as a hydraulic cylinder, which has an operating rod that can be extended and compressed. However, the press actuator can also be embodied as various types of actuators that perform a linearly-reciprocating motion using a motor or an electromagnet. 
     The push rod  153  is coupled to a movable portion of the press actuator  152 , for example, an outer portion of the operating rod, and is intruded into the converter  110  through the guide  131  of the guide housing  118 , so as to reciprocally move the conversion plunger  151  into and out of the cavity  119  of the mold  116  along the guide groove  129  of the guide pad  117 . 
     When the conversion plunger  151  is reciprocated by the push rod  153 , it forces the scraps, loaded in the upper portion of the guide pad  117 , into the cavity  119  of the mold  116  so that the scraps are converted into the form of a high-density block. Although the conversion plunger  151  can be provided integral with the push rod  153 , the conversion plunger  151  is provided as a separate member that is detachably coupled with the push rod  153  in order to facilitate replacement. This can reduce manufacturing costs and maintenance cost of the apparatus. 
     The scrap feeder  170  includes a support  171  erected from the base  101 , a hopper  172  provided above the converter  110  by the support  171 , an inclined loader  173  provided in one region inside the hopper  172 , and an auxiliary loader  174  erected in the other region inside the hopper  172 . 
     The hopper  172  is configured to have an expanding entrance in the upper portion and a narrowing exit in the lower portion. The exit is positioned above the loading portion  130  of the guide pad  117 . The hopper  172  can be designed with various shapes. However, in this embodiment, the hopper  172  is illustrated to have a slope  175  in one region and a vertical surface  176  in the other region in order to facilitate installation and operation of the loader  173  and the auxiliary loader  174 . 
     The loader  173  supplies the metal scraps from the hopper  172  to the guide pad  117  by forcing down the metal scraps through the exit. The loader  173  includes a rotatable transport screw  177  arranged on the slope  175  of the hopper  172 , a driving mechanism for rotating the transport screw  177 , and a transport guide  178  provided around the transport screw  177 . 
     The driving mechanism of the loader  173  includes a shaft holder  179  fixed on the upper portion of the hopper  172 , a rotary shaft  180  rotatably fitted into and coupled with the shaft holder  179 , with one end thereof coupled with the transport screw  177 , a follower sprocket  181  coupled with the outer end of the rotary shaft  180 , a drive sprocket (not shown) connected to the follower sprocket  181  via a chain, and a motor (not shown) for rotating the drive sprocket. 
     The transport guide  178  has an open scrap inlet  182  in the upper portion, a scrap outlet  183  in the lower portion, and a guide  184  having a circular tubular passage that extends from the inlet  182  to the outlet  183 . 
     The auxiliary loader  174  serves to force the metal scraps, congested inside the hopper  172 , toward the exit. The auxiliary loader  174  includes an air cylinder  186  erected in the upper portion of the hopper  172  by the support  185  so as to apply a downward force and a movable pusher  187  coupled with a rod of the air cylinder  186  to reciprocally move along the inner surface of the hopper  172 . 
     The compact conveyor  190  serves to convey a compact, which is discharged from the converter  110  after having been compressed. Although the scrap conveyor  190  can be formed as various types of conveyors, it is illustrated as a belt conveyor in this embodiment. The illustrated compact conveyor  190  includes a drive sprocket  193  provided on one longitudinal end of the frame  191  so as to be rotatable by a motor  196 , a follower sprocket  194  provided on the other longitudinal end of the frame  191  and connected with the drive sprocket  193  via a chain  192 , and a conveyor-belt  194  driven by the chain  192 . Holder plates  195 , which support the compact, are provided on the conveyor belt  194  at certain intervals. 
     Below, a description will be given of the operation of the apparatus for recycling metal scraps according to an exemplary embodiment of the invention. 
     Metal scraps, input into the hopper  172  of the scrap feeder  170 , are supplied into the converter  110 . If the scraps are simple particles, they can be naturally supplied by the weight thereof. The scraps are generally tangled with each other when collected, since they have complicated shapes. In general, it is impossible to naturally supply the scraps. Therefore, the loader  173  is operated to forcibly supply the scraps. That is, as the transport screw  177  is rotated, the scraps received in the hopper  172  are introduced into the transport guide  178  through the scrap inlet  182 , discharged through the outlet  183 , and then supplied into the loading portion  130  of the guide pad  117 . In addition, in some cases, the movable pusher  187  of the auxiliary loader  174  is moved up and down to supply a remaining amount of the scraps into the guide pad  117 . 
     When the scraps are supplied as above, the press actuator  152  drives the conversion plunger  151  into the converter  110 , thereby compressing and converting the scraps. That is, the conversion plunger  151  pushes the scraps into the mold  116  while proceeding on the guide pad  117  through the inside of the guide  131 , thereby converting the scraps into a tightly-compressed solid compact. 
     When the compression of the scraps is completed inside the mold  116  as above, the gate  111  is lowered and the exit of the mold  116  is moved to a position that communicates with the outside through the opening  112  and the outlet  105 , so that the compact is discharged to the conveyor  190 . Afterwards, the discharged compact is transported to a next process site by the conveyor  190  and is input into a molten metal for reuse as a casting material. 
     When the scrap compact is produced by the apparatus for recycling metal scraps according to an exemplary embodiment of the invention as above, it has a specific gravity equal to or more than that of the molten source metal. Thus, when the scrap compact is melted in the molten metal, it sinks inside the molten metal without floating on the surface of the molten metal. Therefore, it is possible to prevent the scraps from being lost due to oxidation, thereby significantly improving the recovery rate of the scraps. 
     Furthermore, the apparatus for recycling metal scraps according to an exemplary embodiment of the invention is configured such that the mold  116  is divided into a plurality of the mold blocks  121 . The stress applied to the mold  116  due to the conversion pressure is significantly reduced compared to that in the integral structure. This, as a result, makes it possible to convert scraps having a high specific gravity into a compact in a short time by applying a high conversion pressure to the scraps. In addition, it is possible to reduce the weight of the mold while increasing the lifetime thereof. 
     Moreover, cutting fluid, input together with the scraps, is discharged to the outside through the gaps between the individual mold blocks  121  of the mold  116  and is then collected by the oil pan  132 . Therefore, it is possible to raise the recovery rate of the cutting fluid and significantly reduce the content of the cutting fluid in the converted scrap compact, thereby significantly decreasing the amount of pollutants which would otherwise occur in a significant amount. 
     The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for the purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.