Abstract:
A dust tight closed type belt conveyor for conveying dust contained materials to be scattered out during operation; which comprises the conveyor belt supported in a form of concave by a plurality of rollers and a plurality of glide plates and also the bulged cover roof closing the upside space over the conveyor belt, so that all make a dust tight and closed conveying space extending in the driving direction. Further, the belt conveyor is preferably provided with a system for avoiding the belt meandering motion causing a harder dust scattering.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a dust tight closed type belt conveyor, and more particularly, to a belt conveyor provided with a cover roof closing an upside space over the conveyor belt which is an easily lay-out system in a narrow space as well as no meandering system for avoiding dust scattering. 
         [0003]    2. Discussion of the Related Art 
         [0004]    Currently, it is generally understood that a belt conveyor is the lowest cost one in the transport mechanism and a number of conveyors have been used in various kinds of factories. However, when materials to be transported sometimes comprise powders or dust-like powders, the powders are easily scattered out to an outside from the conveyor, which may results in degradation of the environment. 
         [0005]    Thus, the belt conveyer needs a device or system for avoiding dust scattering. Therefore, a carrier part and a return part of a belt conveyor and a transfer section are partially covered with a cover (Japanese Utility Model Publication No. 02-94829, No. 04-47149 and Japanese Patent Publication No. 2002-19940). 
         [0006]    In addition, sometimes a rectangle-shaped cover is placed on a flat carrier belt of a conveyor to form a closed passage and a chute is coupled with a cover (Japanese Patent Application Publication No. 09-142665). 
       SUMMARY OF THE INVENTION 
       [0007]    However, in case of the belt conveyor described in the above, it is necessary to arrange large-sized covers so as to cover a carrier side space and a return side space, so that a large layout space is required and sometimes the cover cannot be applied because of insufficient space in the periphery of the belt conveyor. 
         [0008]    Further, in a case of the belt conveyor described in the last case, a cover size is relatively small and arrangement is not limited by the layout of the conveyor. However, the cover is placed on the flat carrier belt, so that there is a gap between the cover and the carrier belt and thus dust may be scattered out for cause of the belt meandering. 
         [0009]    In consideration of the above-mentioned problems regarding the invention, a first object of the present invention is to provide a closed belt conveyor arranged in a dust tight manner which can be easily laid out even in a narrow space. Further, a second object of the present invention is to provide a closed belt conveyor provided with a system for avoiding the belt meandering which causes a harder dust scattering. 
         [0010]    According to a first aspect of this invention, there is provided a dust tight closed type belt conveyor for conveying dust contained materials to be scattered out during operation; 
         [0011]    which comprises: 
         [0012]    1) an endless conveyor belt to be driven for receiving and conveying the materials, being laid out from an upstream side provided with a transfer section from a chute to a downstream side, 
         [0013]    2) a supporting frame for supporting the conveyor belt from the backside thereof comprising a plurality of rollers arranged at regular intervals in a driving direction for supporting a main backside part of the conveyor belt in a concave form and glide plates arranged between the rollers in the driving direction for supporting both edges of the conveyor belt from the backside thereof, 
         [0014]    3) a cover roof extending in the driving direction for dust tightly closing an upside space of the conveyor belt extending in the driving direction comprising top plates pitched so as to spread over from one of the glide plates through the upside space of the conveyor belt to the other of the glide pates, 
         [0015]    whereby the conveyor belt supported in a form of concave by a plurality of rollers, a plurality of the glide plates contacted by the both edges of the conveyor belt and the cover roof closing the upside space over the conveyor belt all make a dust tight and closed conveying space extending in the driving direction. 
         [0016]    In a preferred embodiment of this invention, the left and right side glide plates are upwardly inclined in the outside direction and provided in the conveyor frame, the cover roof comprises first and second top plates attached to cover the carrier belt at the transfer section and the downstream thereof, and the closed-section space is formed by the glide plates, the carrier belt, and the first and second top plates. With such a configuration, it is possible to prevent the dust from being scattered to outside and the installation is not limited due to the layout space. 
         [0017]    In another preferred embodiment of the invention, the carrier belt is bent in the concave shape by the left and right glide plates. With such a configuration, the conveying object is stably mounted on the center of the carrier belt. In addition, since the tension is applied to the carrier belt so as to be pressed inward in the width direction, meandering of the carrier belt can be reduced and suppressed. 
         [0018]    In a further preferred embodiment, each supporting roller comprises horizontal center roller and a pair of half-length side slope rollers arranged at both sides of the center roller and upwardly inclined in the outside direction and each glide plates is arranged at both sides of the conveyor belt and upwardly inclined in the outside direction with a larger oblique angle than that of side slope roller so as to make the edges of the conveyor belt bent inside for preventing meandering motion of the conveyor belt. 
         [0019]    Since the transfer section and the downstream section thereof are constructed in a manner of different structures, a structure for preventing the dust from being scattered from the boundary portion is required. Thus, when the end portion of the first top plate of the transfer section is allowed to overlap with the lower portion of the start portion of the second top plate on the downstream side of the transfer section, for example, by the length in the range of 30 cm to 80 cm, the dust is pulled to the downstream side due to the airflow by travelling of the carrier belt in spite of the fact that there is a gap between the first and second top plates. 
         [0020]    According to another aspect of the invention, the first and second top plates are attached by using the conveyor frame. With such a configuration, since the structure of the invention may be simply applied to the conveyor provided in advance, the practical value thereof is great. The first and second top plates may be attached to the conveyor frame, for example, by bolts, nuts, welding, or the like. Alternatively, when a cup-shaped attachment bracket is fixed to the conveyor frame and the outer end portion of the first top plate and the left and right end portions of the second top plate are fitted into the attachment bracket, the first and second top plates can be attached to the conveyor frame by a simple work. Further, when such an attachment bracket is used, the first and second top plates can be simply detached even in case of an exchange of the first and second top plates for any reason. Accordingly, the exchange work can be simply performed. 
         [0021]    When the first top plate is attached to cover the space between the skirt plate of the chute and the conveyor frame, the first top plate may be attached in any structure. For example, a fitting groove may be formed at the center of the first top plate, the first top plate may be curved in an arc shape at the time of attaching the first top plate to the conveyor frame, and the inner edge portion of the fitting groove may be closely pressed and attached to the skirt plate of the chute. 
         [0022]    A fitting groove may be formed at the center of the first top plate, the first top plate flatly extends inward at the time of attaching the first top plate to the conveyor frame, a flexible curtain and a dustproof member may be fixed to the inner edge of the first top plate, the curtain is suspended and curved inward in a width direction, the lower portion of the curtain comes in slidable contact with the carrier belt, and the dustproof member may be closely attached to the outer surface of the skirt plate of the chute. 
         [0023]    As the dustproof member and the contact member may be made of synthetic resin foam such as urethane foam or a sponge such as a foaming rubber. However, in consideration of the usage circumference of the conveyor belt, it is preferable to use a soft sponge formed of polyethylene based foam having excellent weather resistance, chemical resistance, durability, chemical resistance, and wear resistance. 
         [0024]    The entire of the dustproof member or the contact member may be formed of the soft sponge. However, in consideration of vibrations or impacts to the dustproof member or the contact member, the dustproof member or the contact member may be formed to insert a center member into the soft sponge. The center member may be formed of any material if the center material has elasticity, and the center member is preferably formed of a synthetic resin in consideration of the cost thereof. 
         [0025]    The glide plate may be formed of any material if the carrier belt can come in contact with the glide plate so as to be easily slid. For example, a polyethylene resin with high molecular weight may be used. In addition, the curtain may have flexibility and prevent the dust from being scattered. For example, rubber or soft synthetic resin material may be used. 
         [0026]    In the transfer section, it is preferable that the carrier belt smoothly bent in the concave shape and then vertical rollers are obliquely provided on the upstream side thereof. That is, it is preferable that slope rollers are provided in the left and the right of the upstream side of the transfer section and the portion of the carrier belt coming out from the transfer section is bent in a concave shape. 
         [0027]    Further, it is preferable that a plurality of horizontal rollers for receiving the carrier belt are provided in the center in the width direction of the conveyor frame through the whole length in the longitudinal direction thereof with intervals. Particularly, in order to avoid the carrier belt fluctuating up and down due to the impact at the time of receiving the conveying object from the chute, it is preferable that the horizontal rollers are provided with short intervals. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is a schematic constituent diagram illustrating a preferred embodiment of a closed type belt conveyor according to the invention. 
           [0029]      FIG. 2  is a constituent diagram illustrating a structure of a transfer section A and a direct downstream side thereof in the embodiment. 
           [0030]      FIG. 3  is a constituent diagram illustrating a structure of a transfer section A in the embodiment. 
           [0031]      FIG. 4  is a constituent diagram illustrating a structure of a downstream side of a transfer section A in the embodiment. 
           [0032]      FIG. 5  is a constituent diagram illustrating a structure of a horizontal roller  14  of a transfer section A in the embodiment. 
           [0033]      FIG. 6  is a constituent diagram illustrating a structure of an upstream side of a transfer section A in a second embodiment. 
           [0034]      FIG. 7  is a constituent diagram illustrating a structure of a transfer section A in the embodiment. 
           [0035]      FIG. 8  is a constituent diagram illustrating a structure a boundary portion between a transfer section A and a downstream side in the embodiment. 
           [0036]      FIG. 9  is a constituent diagram illustrating a structure of a downstream side of a transfer section A in the embodiment. 
           [0037]      FIG. 10  is a schematic perspective view showing a dustproof apparatus of a belt conveyer according to a preferred embodiment of the present invention. 
           [0038]      FIG. 11  is a sectional front configuration view showing the dustproof apparatus. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0039]    Hereinafter, the invention will be described in detail with reference to detailed examples shown in the drawings.  FIGS. 1 to 5  show preferred embodiments of the closed type belt conveyor according to the invention. The closed type belt conveyor according to the embodiment has the same structure as that of a schematic diagram shown in  FIG. 1 . That is, a conveyor belt B is suspended in an endless shape between rollers R 1  and R 2  at both front and rear ends thereof and any one of the rollers R 1  and R 2  is driven by a driving motor (not shown), thereby traveling the conveyor belt B in the endless shape. 
         [0040]    A transfer section A is provided in a travel start portion of carrier belt B. In the transfer section A, a conveying object from a chute S is received to the carrier belt B to be conveyed to the downstream side. A curtain N made of rubber or soft synthetic resin for prevent dust from be scattered is provided in the start portion of the transfer section A and the lower end of the curtain N comes in contact with the carrier belt B so as to be slid or appropriates the carrier belt B. The upper portion of the carrier belt B is covered with first and second top plates T 1  and T 2  and the end portion of the second top plate T 2  is inserted into a chute box SB of the belt conveyor. 
         [0041]    Next, the detailed structure of the embodiment will be described with reference to  FIGS. 2 to 5 . In  FIGS. 2 to 5 , a conveyor frame  10  is constituted by a mount frame  11 , a brace  12  mounted on the mount frame  11 , and a carrier stand  13 . A driving roller and a driven roller (not shown) are rotatably supported at both front and rear ends of the conveyor frame  10 . 
         [0042]    As shown in  FIG. 2 , a plurality of horizontal rollers  14  are disposed at the center of the conveyor frame  10  under the carrier belt B in the width direction through the whole length in the longitudinal direction with predetermined intervals and are rotatably supported between the left and right supporters  11 A and  13 A fixed to the mount frame  11 . 
         [0043]    The transfer section A is provided on the upstream side of the belt conveyor close to the carrier. In the transfer section A, skirt plates  17  at the left and right of the chute are disposed to extend in the longitudinal direction with intervals therebetween and are attached to the brace  12  of the conveyor frame  10 . In the transfer section. 
         [0044]    A, the intervals of the above-described horizontal rollers  14  are set to be smaller than those of the horizontal rollers  14  on the downstream side of the transfer section A and it is avoided that the carrier belt B waves due to the impact at the time of receiving the conveying object dropped from the chute. 
         [0045]    Vertical rollers  15  are provided in both left and right sides of the start portion of the transfer section A, for example, at 45− from the vertical line, the vertical rollers  15  is rotatably supported between the carrier stand  13  and the supporter  13 A, and the vertical rollers  15  bend the carrier belt B in a concave shape so as to send the carrier belt B to the transfer section A. 
         [0046]    A glide plate  18  made of polyethylene with high molecular weight is obliquely provided to extend at the substantially whole length in the longitudinal direction from the transfer section A to the carrier end portion. The glide plate  18  is supported to the carrier stand  13  with a reception bracket  18 A interposed therebetween, comes in contact with both side portions of the carrier belt B having the concave portion so as to be slid, and sends the carrier belt B with the concave shape to the carrier end portion. 
         [0047]    Slope rollers  16  which are shorter than the vertical rollers  15  are provided in the lower portion of the glide plate  18 . The slope rollers  16  are rotatably supported between the carrier stand  13  and the supporter  13 A and glide the movement of the carrier belt B by the left and right slope rollers  16  and the horizontal rollers  14 . 
         [0048]    In addition, a cup-shaped attachment bracket  13 B is fixed to the upper end of the reception bracket  18 A of the left and right carrier stands  13  by a welding or an attachment screw. In the transfer section A, the outer end portion of the first top plate  20  which is a zinc coating plate is fitted into the attachment bracket  13 B and is fixed by the attachment screw. The first top plate  20  covers the space between the skirt plate  17  and the carrier stand  13 . A closed-section space M 1  is formed in both sides of the skirt plate  17  of the chute by the glide plate  18 , the first top plate  20 , and the carrier belt B. 
         [0049]    In the first top plate  20 , a fitting groove is formed in the center in the width direction and the skirt plate  17  of the chute is fitted into the fitting groove. The inner edge of the fitting groove of the first top plate  20  comes in contact with the a curved portion  17 A of the upper end of the skirt plate  17  and thus the first top plate  20  is bent in an arc shape, thereby not pulling out the first top plate  20 . 
         [0050]    A soft sponge cap  17 C is attached to the skirt plate  17  by the attachment bracket, and the cape  17 C is tightly pressed by both edge portions of the carrier belt B. 
         [0051]    On the downstream side from the transfer section A, the outer end portion of the second top plate  25  which is the zinc coating plate is fitted to the left and right attachment brackets  13 B and fixed by the attachment screw. The second top plate  25  is curved in the arc shape and covers the upper portions of the carrier belt B and the glide plate  18 . In addition, a closed-section space M 2  is formed in the upper portion of the carrier belt by the glide plate  18 , the second top plate  25 , and the carrier belt B. 
         [0052]    In the direct downstream side of the transfer section A, the end portion of the first top plate  20  overlaps with and is inserted to the lower portion of the start portion of the second top plate  25  and, for example, by about 50 cm. 
         [0053]    When the conveying object is dropped from the chute, the conveying object is received to the carrier belt B in the transfer section A and conveyed to the downstream side by the carrier belt B. 
         [0054]    At that time, the power-shaped object contained in the conveying object becomes dust and flies in the transfer section A and the downstream side D thereof. In the transfer section A, the closed-section space M 1  is formed by the skirt plate  17 , the first top plate  20 , and the glide plate  18 . Further, the gap in the transfer section A is practically closed. Accordingly, the dust is not scattered from the transfer section A to the circumference. 
         [0055]    In addition, since the closed-section space M 2  is formed on the downstream side D of the transfer section A by the carrier belt B, the second top plate  25 , and the glide plate  19 , the dust is not scattered from the downstream side D of the transfer section A to the circumference. 
         [0056]    Further, in the boundary C between the transfer section A and the downstream side thereof, the first and second top plates  20  and  25  overlap with each other so that the former is the lower and the dust is pulled toward the downstream side D of the transfer section A by the airflow upon traveling the carrier belt B. Accordingly, the dust is not scattered from the boundary C between the first and second top plates  20  and  25 . 
         [0057]    As described above, the first and second top plates  20  and  25  are attached to the conveyor frame  10 , the closed-section space M 1  is formed in both sides of the skirt plate  17  of the chute in the transfer section A, and the closed-section space M 2  for conveying the conveying object is formed. Accordingly, it is possible to reliably prevent the dust from being scattered to the circumference. Further, the belt conveyor has a compact size and thus there is no case where the installation is limited due to the layout space. 
         [0058]    Since the carrier belt B is bent in the concave shape by the glide plate  18 , the conveying object is stably mounted at the center of the carrier belt B. In addition, since tension is applied to the carrier belt B to be pressed inward in the width direction by the glide plate  18 , the meander of the carrier belt B is reduced and suppressed. 
         [0059]    On the downstream side D of the transfer section A, the slope roller  16  has the short size and only glide plate  18  is exposed in the side of the conveyor frame  10 . Accordingly, a case where fingers of a worker are caught between the rollers at the time of checking the belt conveyor to damage the worker scarcely occurs. 
         [0060]      FIGS. 6 to 9  show a second embodiment. In  FIGS. 6 to 9 , the same reference numerals as those in  FIGS. 1 to 5  indicate the same or corresponding parts. In this embodiment, a first glide plate  18  is provided between the vertical rollers of the start portion and the end portion of the transfer section A so as to extend in the longitudinal direction of the first glide plate  18  in the sectional arc shapes in both left and right sides thereof, the upper end portion of the first glide plate  18  is attached to the brace  12 , and the lower end portion of the first glide  18  is placed on the cushion such as a soft sponge on the supporter  12 A and attached to absorb impacts or vibrations by the press of the attachment bracket. 
         [0061]    The first glide plate  18  is manufactured, for example, by using a polyethylene resin with high molecular weight and sends the carrier belt B curved by the vertical roller  15  of the start portion to the downstream side D with the carrier belt B kept in the U shape. 
         [0062]    On the downstream side D of the transfer section A, a flat (or sectional arc-shaped) second glide plate  19  is obliquely disposed in the upper portion of the slope roller  16  to extend through the whole length in the longitudinal direction, is received to the reception bracket  18 A, and is attached to the carrier stand  13 . The carrier belt B coming from the transfer section A is kept in the concave shape as shown in  FIGS. 8 and 9 . 
         [0063]    In the transfer section A, the first top plate  20  having a narrow width extends inward and is fixed to the upper end of the carrier stand  13 , a curtain  21  and the a dustproof member  22  are fixed to the inner end of the first top plate  20 . The flexible curtain  21  is manufactured, for example, by using polyethylene resin with high molecular weight and extends through the whole length in the longitudinal direction of the transfer section A. Further, the lower portion of the curtain  21  is curved inward in the width direction and comes in contact with the carrier belt B so as to be slid. 
         [0064]    The dustproof member  22  is manufactured, for example, by using a foaming polyethylene resin and is closely attached to the skirt plate  17  of the chute. In this manner, a closed-section space M 1  is formed in the outer portion of the skirt plate  17 . 
         [0065]    Similarly with the first embodiment, on the downstream side D of the transfer section A, the          -shaped attachment bracket  13 B is fixed to the reception brackets  18 A of the left and right carrier stands  13 , both end portions of the second top plate  25  are fitted into the attachment bracket  13 B and fixed by the attachment screw, the second top plate  25  is curved in the arc shape and pulled out, and a closed-section space M 2  is formed by the second glide plate  19 , the carrier belt B, and the second top plate  25 . 
         [0066]    The first top plate  20  and the curtain  21  enter the lower portion of the second top plate  25  in the direct downstream side of the transfer section A. A contact member  26  is disposed between a structure including the curtain  21 , the first top plate  20 , and the first glide plate  18  and a structure including the second top plate  25  and the second glide plate  19 , whereby the curtain  21 , the first top plate  20  and the first glide plate  18  are connected to the second top plate  25  and the second glide plate  19 . 
         [0067]    In the first embodiment, the cap  17 A is provided on the skirt plate  17 . However, since the scattering of the dust is suppressed by the closed-section space M 1 , the cap  17 A is not necessarily provided. 
         [0068]    Meanwhile, in the second embodiment, the contact member  26  is provided. However, since the dust is not scattered from the boundary between the transfer section A and the downstream side by pulling the dust by the airflow upon traveling the carrier belt B, the contact member  26  is not necessarily provided. 
         [0069]      FIGS. 10 and 11  show a third embodiment, in which a dustproof box  300  is provided in a immediate downstream side of a connection part  200  of a belt conveyer and a downstream side of the dustproof box  300  is configured into an enclosed structure illustrated in the first and second embodiments by a top plate. 
         [0070]    The dustproof box  300  is configured to have a shape that covers the conveyer belt  100  by left and light side plates and the top plate, and the dustproof box  300  is supported to a conveyer frame  10  by a support frame  310 . 
         [0071]    An inlet side of the dustproof box  300  is connected to an outlet of the connection part  200  and an outlet side thereof is closed by a plate. A short split curtain (not shown) made of rubber or synthetic resin is attached to a lower border of the outlet side. The dustproof box  300  has a sufficiently large sectional area so as to sufficiently decrease a flow speed of air containing dust blown off from a conveying port of the connection part  200 . 
         [0072]    A plurality of mesh plates (dust interference unit)  330  are disposed and fixed in the dustproof box  300  with a predetermined distance therebetween in a belt conveying direction so as to partition the inside of the dustproof box  300 . A short split curtain  340  made of rubber or synthetic resin is attached to a lower border of each of the mesh plates  330 . The mesh plates  330  are preferably configured such that meshes become gradually smaller in a belt conveying direction, and it is preferable to form the meshes of an upper half of the mesh plate to be smaller than those of a lower half thereof. 
         [0073]    Furthermore, opposite ends of a bar member  380  is rotatably supported to both side plates of the dustproof box  300  in the vicinity of each of the mesh plates  330 . A handle  390  is fixed to one end of the bar member  380  and a major part of an intermediate portion of the bar member  380  is bent into a crank shape with respect to opposite end portions thereof. By rotating the handle  390 , the bar member beats the mesh plate  330  to drop the adhered dust onto a transport object W. Openable inspection windows  390  are formed in a side wall of the dustproof box  300  with appropriate intervals. 
         [0074]    In addition, sponge skirts  400  extend at both left and right sides of the dustproof box  300  in a belt conveying direction. The sponge skirts  400  are preferably made of cross-linked polyethylene foam in view of wear resistance, water resistance and weather resistance. 
         [0075]    When the transport object is dropped from a chute, the transport object is received by the conveyer belt  100  in the connection part  200  and conveyed to the downstream side by the conveyer belt  100 . At this time, powdery materials contained in the transport object W become dust in the connection part  200  to be kicked up by the impact caused by dropping the transport object onto the connection part  200 . 
         [0076]    Furthermore, the dust kicked up in the connection part  200  is blown off from the conveying port together with air and glided into the dustproof box  300 . Since a sectional area of the dustproof box  300  is sufficiently large, a flow speed of air containing the dust is remarkably decreased, and dusts having large sizes are dropped on the transport object W disposed on the conveyer belt  100  by their own weights due to decrease of the flow speed. Meanwhile, dusts having large sizes which are not dropped by their own weights first collide to a first mesh plate  330 , and some of them are dropped on the transport object W disposed on the conveyer belt  100  and the remainder is adhered to the mesh plate  330 . 
         [0077]    The dusts having small sizes which have passed through the first mesh plate  330  are decreased in a flow speed, and the dusts are dropped by their own weights on the transport object W disposed on the conveyer belt  100 . Meanwhile, dusts having large sizes which are not dropped by their own weight collide to a second mesh plate  330 , and some of them are dropped on the transport object W disposed on the conveyer belt  100  and the remainder is adhered to the mesh plate  330 . 
         [0078]    In this manner, air containing dust is gradually decreased in a flow speed whenever the air passes through the mesh plates  330 , and upon arriving at the final mesh plate  330 , the air becomes like a state of being remained in the dustproof box  300  so that dusts having very small sizes are dropped by their own weight and dusts which are not dropped collide to the mesh plate  330  to be dropped or adhered to the mesh plate  330 . Therefore, the air substantially not containing dusts is sent out of the dustproof box  300 . 
         [0079]    On the other hand, in cases where the clogging of the mesh plate  330  or the like is caused, an operator opens a cover of the inspection window  350  to inspect a place where the clogging is occurred and the bar member  380  can beat the mesh plate  330  by rotating the handle  390  located at the place, to get rid of the clogging.