Abstract:
A retractable and extendable material loader that directs material onto a conveying surface of a belt conveyor has a retractable and extendable tubular length where the length of the loader is extended to direct material through the loader onto the conveyor, and a length of the loader is retracted when the loader is not directing material onto the conveyor to provide adequate clearance for material loaded onto the conveyor by another loader located upstream of the retractable and extendable loader. The apparatus provides improved environmental conditions over the current art, improved health and safety conditions of personnel over the current art, and improved operational safety conditions in respect to explosion risk over the current art.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention pertains to a bulk material loader that directs material onto a conveying surface of a belt conveyor. In particular, the present invention is a material loader that has a retractable and extendable tubular length where the length of the loader is extended to direct material through the loader onto the moving belt surface of a conveyor, and the length of the loader is retracted when the loader is not directing material onto the conveyor to provide adequate clearance for material loaded onto the conveyor by another loader located upstream of the conveyor. 
   2. Description of the Related Art 
   The transporting of bulk material, for example coal, from one area to another often involves the transfer of a stream or flow of the material from two or more conveyors onto another, single conveyor. In the transfer of the material from one conveyor to a second conveyor, it is often necessary that the material be discharged from the first conveyor into a tubular loader. The material falls through the tubular loader and is directed by the loader onto the conveying surface of the second conveyor. The bulk material exits a bottom opening of the tubular loader and impacts with the moving conveying surface of the second conveyor. 
   The conveying surface of the second conveyor is often moving at a slower speed than the speed of the bulk material falling through the loader. The faster speed of the material impacting the conveying surface can result in spillage of the bulk material from the sides of the conveying surface. To reduce the amount of spillage, it is desirable that the exit opening or bottom opening of the tubular loader be positioned in close proximity to the conveying surface so that the material exiting the bottom opening has a minimum amount of undirected free-fall to the conveying surface. 
   The need to position the bottom exit opening of the tubular loader in close proximity to the conveying surface presents problems when two or more conveyors discharge bulk material to two or more tubular loaders that direct the material to a single receiving conveyor. The two loaders are positioned along the length of the receiving conveyor with the first of the loaders positioned toward the upstream end of the receiving conveyor and the second of the loaders positioned in the downstream direction of the receiving conveyor from the first loader. The two discharging conveyors are typically alternately operated so that only one conveyor at a time is discharging bulk material to one of the two loaders, and the one loader is directing the material onto the receiving conveyor. With this arrangement, it is possible to position the bottom outlet opening of the first, upstream loader in close proximity to the conveying surface of the conveyor. However, the bottom, outlet opening of the second, downstream loader cannot be positioned in close proximity to the conveying surface of the receiving conveyor without coming into contact with material loaded onto the conveying surface by the upstream loader. The bottom, outlet opening of the second, downstream loader must be positioned higher above the conveying surface of the receiving conveyor than the bottom, outlet opening of the first, upstream loader in order to provide adequate clearance for the material loaded onto the conveying surface by the first, upstream loader to pass beneath the bottom outlet opening of the second, downstream loader. The need to position the bottom outlet opening of the second, downstream loader at a higher position above the conveying surface presents the problem of increased spillage of the bulk material directed through the second, downstream loader onto the conveying surface. 
   SUMMARY OF THE INVENTION 
   The retractable and extendable material loader apparatus of the present invention overcomes the disadvantages associated with the prior art second, downstream material loader that directs material onto a conveying surface of a conveyor downstream from a first, upstream loader. The apparatus provides improved environmental conditions over the current art, improved health and safety conditions of personnel over the current art, and improved operational safety conditions in respect to explosion risk over the current art. This is accomplished by providing the material loader apparatus with a retractable and extendable length where the length can be extended to discharge material onto a conveying surface, and can be retracted to provide adequate clearance for material discharged onto the conveying surface by the first, upstream loader. The material loader apparatus of the invention thereby overcomes the disadvantages associated with prior art loader apparatus that direct bulk material from two or more supply conveyors, through two or more loader apparatus to a single receiving conveyor. 
   The retractable and extendable material loader apparatus of the invention is designed as part of a conventional funnel-shaped hopper or transition chute that receives a supply of bulk material from a discharge conveyor and directs the received bulk material onto the conveying surface of a receiving conveyor. The retractable and extendable material loader apparatus is basically comprised of a first, upper tubular section and a second, lower tubular section that are connected together for telescoping movement. The apparatus is designed to be used on any number of transition chutes that receive bulk material from any number of discharge conveyors and direct the bulk material to the conveying surface of a single receiving conveyor. 
   The first, upper tubular section is connected to a lower end of the funnel-shaped transition chute where it receives bulk material falling through the chute. The upper tubular section has a cylindrical upper sidewall, with opposite top and bottom openings. The upper sidewall receives the bulk material from the funnel-shaped chute and directs the material through the upper sidewall. 
   The second, lower tubular section is connected to the first, upper tubular section for relative telescoping movement of the lower section over the upper section. The lower tubular section has a conical lower sidewall with opposite top and bottom openings. The lower sidewall extends around the upper sidewall to receive the material exiting the upper sidewall and to direct the material through the lower sidewall. The material exits the lower sidewall onto the conveying surface of the belt conveyor. 
   The upper and lower sidewalls are moveable between retracted relative positions where the upper and lower sidewalls have a first combined length, and extended relative positions where the upper and lower sidewalls have a second combined length that is larger than the first combined length. 
   A plurality of actuators are operatively connected between the upper and lower sidewalls. The actuators are selectively operable to move the lower sidewall over the upper sidewall between the retracted relative positions and the extended relative positions of the upper and lower sidewalls. 
   A plurality of vertical columns are fixed stationary to the upper tubular section. The columns are spatially arranged around the upper tubular section and are parallel to each other. The columns have lengths that extend downwardly alongside the upper tubular section and alongside a portion of the lower tubular section. 
   A plurality of rollers are mounted on the lower tubular section. The rollers are spatially arranged around the lower tubular section at positions that correspond to the positions of the plurality of columns on the upper tubular section. The pluralities of rollers engage in rolling contact with the plurality of columns. Surfaces of the columns that engage with the rollers function as guide surfaces that direct the rollers vertically upwardly and downwardly across the columns as the lower tubular section is telescoped upwardly and downwardly over the upper tubular section by operation of the actuators. Stop surfaces are provided on the plurality of columns where the rollers will engage with the stop surfaces when the lower tubular section is moved to its extended position relative to the upper tubular section to prevent further movement of the lower tubular section toward the extended position. 
   In operation, the retractable and extendable material loader is positioned along a conveyor in a downstream direction from at least one other material loader positioned upstream along the conveyor. When the other upstream material loader is not loading material on the conveyor and the retractable and extendable material loader is loading material on the conveyor, the actuators are operated to extend the lower tubular section from the upper tubular section. This positions the bottom opening of the lower tubular section in close proximity to the conveying surface of the conveyor. Bulk material is then loaded onto the conveying surface of the conveyor through the upper tubular section and the extended lower tubular section. The positioning of the lower tubular section in close proximity to the conveying surface reduces the potential for spillage of the material as it exits the extended lower tubular section and contacts the moving conveying surface. 
   When it is desirable to load material onto the conveying surface from the other upstream material loader, the actuators of the retractable and extendable material loader are then operated to move the lower tubular section upwardly to the retracted position relative to the upper tubular section. This raises the lower tubular section above the conveying surface and provides adequate clearance for the material loaded onto the conveying surface from the other upstream material loader to pass beneath the retractable and extendable material loader. 
   Thus, the apparatus of the invention overcomes the problem of spillage of material from a moving conveying surface by a second material loader positioned along the conveying surface. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further the features of the invention are set forth in the following detailed description of the invention and in the drawing figures. 
       FIG. 1  is a schematic representation of one operative environment of the retractable and extendable material loader apparatus of the invention. 
       FIG. 2  is a side elevation view of the apparatus in the extended length condition of the apparatus. 
       FIG. 3  is a side elevation view of the apparatus in the retracted length condition of the apparatus. 
       FIG. 4  is a top plan view of the apparatus. 
       FIG. 5  is a partial side elevation view of a portion of the apparatus. 
       FIG. 6  is a partial top plan view of a portion of the apparatus. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  is a schematic representation of one operative environment of the retractable and extendable material loader apparatus  10  of the present invention. It should be understood that the environment of  FIG. 1  is only one example of an environment in which the apparatus may be used. There are other environments where the apparatus of the invention is equally well suited for use, and  FIG. 1  should not be interpreted as the only operative environment in which the apparatus of the invention may be used. 
   A schematic representation of a conveyor  12  having a belt conveying surface  14  is shown in  FIG. 1 . The conveyor  12  is any conventional design of a belt conveyor that conveys bulk material in a downstream direction from an upstream end  16  of the conveyor shown to the left of  FIG. 1 , to a downstream end  18  of the conveyor shown to the right in  FIG. 1 . The conveyor  12  is basically comprised of a frame that supports a plurality of rollers  20 . The rollers  20  are arranged to support the belt conveying surface  14  in a u-shaped configuration that extends into the plane of  FIG. 1 . The u-shaped configuration of the conveying surface  14  forms a moving trough. The trough supports bulk material, for example coal, delivered onto the conveying surface  14  and prevents the spillage of the bulk material from the opposite sides of the conveying surface. 
     FIG. 1  also shows a schematic representation of a bulk material transfer  22  positioned toward the upstream end  16  of the conveyor  12 . Bulk material transfer  22  of the type shown in  FIG. 1  are known in the art, and therefore the component parts of the transfer  22  will be described only generally. Basically, the loader includes a funnel-shaped hopper or chute  24  that is selectively supplied with bulk material from a separate, discharge conveyor  30 . The bulk material supplied to the chute  24  by the discharge conveyor  30  falls through the chute and is directed to a loading tube  26  positioned at the bottom of the chute  24 . The bulk material continues to fall through the loading tube  26  and is directed by a loading chute  28  at the bottom of the loading tube  26  onto the conveying surface  14  of the conveyor  12 . The loading chute  28  is partially positioned within the u-shaped cross-section of the conveying surface  14  to avoid the spillage of the bulk material loaded onto the conveying surface  14  off of the opposite sides of the conveying surface. 
   A pair of side plates or guards  32  are positioned on the opposite sides of the conveyor  12 . The guards also aid in preventing the bulk material loaded onto the conveying surface  14  from spilling off of the opposite sides of the conveyor  12  due to the impact of the bulk material on the conveying surface  14 . The bulk material loaded onto the conveying surface  14  is conveyed in the downstream direction to the right as shown in  FIG. 1 . 
     FIG. 1  also shows a second, downstream bulk material transfer  22 ′ that has been modified with the retractable and extendable material loader apparatus  10  of the present invention. Many of the component parts of the downstream material transfer  22 ′ are the same as those of the upstream transfer  22 , and are identified with the same reference numbers followed by a prime (′). It can be seen from viewing  FIG. 1  that the bulk material loaded onto the conveying surface  14  from the upstream material loader  22  would contact the loading chute  28 ′ of the downstream material transfer  22 ′ as the material is conveyed in the downstream direction. As explained earlier, in the prior art this required that the loading tube  26 ′ and loading chute  28 ′ of the prior art downstream transfer  22 ′ be elevated above the conveyor  12  to provide clearance for the bulk material being conveyed beneath the downstream loader. This disadvantage of the prior art is overcome by the retractable and extendable material loader apparatus  10  of the invention. The retractable and extendable material loader apparatus  10  has a length that can be extended to discharge material onto the conveying surface  14 , and can be retracted to provide adequate clearance for material discharged onto the conveying surface  14  by the first, upstream transfer  22 . The retractable and extendable material loader apparatus  10  thereby overcomes the disadvantages associated with prior art loader apparatus that direct bulk material from two or more supply conveyors, through two or more loader apparatus to a single receiving conveyor. 
   As represented schematically in  FIG. 1 , the retractable and extendable material loader apparatus  10  is designed to be assembled to a conventional funnel shaped transition chute  24 ′ of a bulk material transfer  22 ′. The transition chute  24 ′ receives bulk material from a separate discharge conveyor  30  and directs the bulk material into the retractable and extendable material loader apparatus  10 . The apparatus  10  then directs the material through a conventional loading chute  28 ′ to the conveying surface  14  of the conveyor  12 . 
     FIGS. 2 and 3  show the retractable and extendable material loader apparatus  10  removed from the bulk material transfer  22 ′ of  FIG. 1 . The apparatus  10  is basically comprised of a first, upper tubular section  42  and a second, lower tubular section  44 . The upper section  42  and lower section  44  are connected together for relative telescoping movement between retracted and extended relative positions. The telescoping movement is produced by a plurality of actuators  46  that are operatively connected between the upper tubular section  42  and the lower tubular section  44 . 
   The first, upper tubular section  42  is designed to be connected to the lower end of the funnel-shaped transition chute  24 ′ of a conventional bulk material transfer  22 ′. The upper tubular section  42  is primarily comprised of a cylindrical upper sidewall  48 . The upper sidewall  48  has a length that extends between a circular top edge  52  of the sidewall that defines a top opening, and an opposite circular bottom edge  54  of the sidewall that defines a bottom opening. A hollow interior bore  56  extends through the length of the upper sidewall  48  between the top edge  52  and the bottom edge  54 . The interior bore  56  has a center axis  58 . The interior bore  56  receives the bulk material from the transition chute  24 ′ through the top opening defined by the sidewall top edge  52 , and directs the material through the upper sidewall  48  with the material exiting the upper sidewall through the bottom opening defined by the sidewall bottom edge  54 . 
   The second, lower tubular section  44  is primarily comprised of a conical lower sidewall  62 . The lower sidewall  62  has a circular top edge  64  that defines a top opening into the sidewall, and a circular bottom edge  66  that defines a bottom opening of the sidewall. A hollow interior bore  68  extends through the lower sidewall  62  from the top opening defined by the top edge  64  to the bottom opening defined by the bottom edge  66 . The interior bore  68  of the lower sidewall has a center axis that is coaxial with the center axis  58  of the upper sidewall  48 . The lower sidewall  62  extending around the upper sidewall  48  positions the lower sidewall to receive material exiting the upper sidewall through the top opening defined by the lower sidewall top edge  64 , and to direct the material through the lower sidewall with the material exiting the lower sidewall through the bottom opening defined by the lower sidewall bottom edge  66 . The material exiting the lower sidewall  62  is directed by a loading chute  28 ′ onto the conveying surface  14  of the belt conveyor  12 . 
   As seen in  FIGS. 2 and 3 , the interior diameter of the lower sidewall  62  gets larger as the sidewall extends from its bottom edge  66  to its top edge  64 . This enables the lowered sidewall  62  to telescope over the upper sidewall  48 .  FIGS. 1 and 2  show the lower sidewall  62  and the upper sidewall  48  in their extended, relative positions.  FIG. 3  shows the lower sidewall  62  and the upper sidewall  48  in their retracted relative positions. From comparing  FIGS. 2 and 3 , it can be seen that in the extended relative positions of the upper  48  and lower  62  sidewalls, the combined interior bores  56 ,  68  have a larger length than the combined interior bores of the upper sidewall  48  and lower sidewall  62  in the retracted relative positions. In both the extended relative positions shown in  FIG. 2  and the retracted relative positions shown in  FIG. 3 , a portion of the lower sidewall  62  surrounds and telescopes over a portion of the upper sidewall  48 . 
   A generally flexible, collapsible sealing boot  72  is connected between the upper sidewall  48  and lower sidewall  62 . The boot  72  prevents dust from the bulk material passing through the upper tubular section  42  and lower tubular section  44  from escaping between the connection of the two sections.  FIG. 2  shows the boot  72  in its extended position connecting the upper tubular section  42  to the lower tubular section  44 :  FIG. 3  shows the boot  72  in its collapsed position. 
   In the embodiment shown in the drawing Figures, there are three actuators  46  operatively connected between the upper tubular section  42  and the lower tubular section  44 . As seen in  FIG. 4 , the actuators  46  are spacially arranged around the peripheries of the two tubular sections. Each of the actuators  46  is connected by pivoting connections to projecting flanges  74  on the upper tubular section  42  and projecting flanges  76  on the lower tubular section  44 . These flanges  74 ,  76  operatively connect the actuators  46  between the upper  42  and lower  44  tubular sections. The particular actuators  46  shown in the drawing Figures are pneumatic actuators. As is conventional, supplying pressurized air to opposite fittings at the opposite ends of the actuators selectively extends and retracts a piston rod and selectively moves the upper  42  and lower  44  tubular sections between their extended positions shown in  FIG. 2  and their retracted positions shown in  FIG. 3 . Although pneumatic actuators  46  are shown in the drawing Figures, other functionally equivalent actuators may be employed. 
   A plurality of straight, parallel columns  78  are fixed stationery to the upper tubular section  42  in positions that are parallel to the center axis  58  of the upper  48  and lower  62  sidewalls. The columns  78  are cylindrical along their lengths, and have peaked ridges or rails  82  that extend along their lengths. The rails  82  are positioned on the columns opposing the upper  42  and lower  44  tubular sections. Each of the columns  78  is connected to the upper tubular section  42  adjacent the top edge  52  of the upper sidewall  48  by arm assemblies  84  that project radially outwardly from the upper sidewall  48 . The arm assemblies  84  space the columns  78  radially outwardly from both the upper sidewall  48  and lower sidewall  62 . The bottom ends of the columns  78  are interconnected by a circular rim  86 . The rim  86  is spaced radially outwardly from the lower sidewall  62 . The columns  78  have lengths that extend downwardly alongside the upper tubular section  42 , across the top opening defined by the top edge  64  of the lower sidewall  62 , across the bottom opening defined by the bottom edge  54  of the upper sidewall  48 , and alongside a portion of the lower sidewall length  62 . The surfaces of the columns function as guide surfaces that direct the telescoping movement of the lower tubular section  44  across the upper tubular  42 , as will be explained. The columns  78  extend along the length of the upper sidewall  48  and along a portion of the length of the lower sidewall  62  when the upper  48  and lower  62  sidewalls are in their extended relative positions. As shown in  FIG. 3 , the columns  78  extend beyond the combined lengths of the upper sidewall  48  and lower sidewall  62  when the upper  48  and lower  62  sidewalls are in their retracted relative positions. 
   Adjacent the rim  86 , each of the columns  78  is provided with a stop surface  88 . The detail of each stop surface  88  can be seen in  FIG. 5 . The position of the stop surface  88  is adjustable along the length of the column  78 . The stop surfaces  88  function to limit the movement of the lower sidewall  62  downwardly from the upper sidewall  48  to the extended relative positions of the upper  48  and lower  62  sidewalls, as will be explained. 
   The plurality of follower arms  92  projected radially outwardly from the lower tubular section  44 . The follower arms  92  are spacially arranged around the circumference of the lower sidewall  62  of the lower tubular section  44 . The positions of the follower arms  92  correspond to the positions of the columns  78  on the upper tubular section  42 . The follower arms  92  have openings  94  that receive the columns  78 . The columns  78  extending through the follower arm openings  94  guide the follower arms  92  and maintain the lower sidewall  62  in its coaxially aligned position relative to the upper sidewall  48  as the lower tubular section  44  telescopes over the upper tubular section  42 . 
   A plurality of rollers  96  are mounted on the follower arms  92 . As shown in the detail of  FIG. 6 , the plurality of rollers  96  are mounted for rotation on the follower arms  92  at positions around the openings  94  through the follower arms. Furthermore, the plurality of rollers  96  are mounted on the follower arms  92  in rolling engagement with the exterior surfaces of the columns  78 . Pairs of the plurality of rollers  96  engage with the columns  78  on opposite sides of the columns to precisely maintain the lower tubular section  44  in its coaxially aligned position relative to the upper tubular section  42  as the lower tubular section is moved between the retracted and extended positions. The surfaces of the columns  78  that engage with the rollers  96  function as guide surfaces that direct the rollers vertically upwardly and downwardly across the columns as the lower tubular section  44  is telescoped upwardly and downwardly over the upper tubular section  42  by operation of the actuators  46 . In addition to the above, at least one of the rollers  96  on each follower arm  92  is positioned to engage the opposite side of the columns  78  from the lower tubular section  44 . This further positively positions the lower tubular section  44  in its axially aligned orientation with the upper tubular section  42  as the sections are moved between their extended and retracted relative positions. 
   An additional set of rollers  98  is provided on each of the follower arms  92 . The additional rollers  98  have v-shaped engagement surfaces that engage in rolling engagement with the peaked surfaces of the column rails  82 . The engagement of these additional rollers  98  with the column rails  82  further positively positions the lower tubular section  48  relative to the upper tubular section  44  as the two sections are moved between their extended and retracted relative positions. In addition, the additional rollers  98  are positioned relative to the column stop surfaces  88  to engage against these surfaces  88  as shown in  FIG. 2  when the lower tubular section  44  is moved to the extended position relative to the upper tubular section  42 . The additional rollers  98  engage against the stop surfaces  88  to prevent further movement of the lower tubular section toward the extended position. 
   In operation, the retractable and extendable material loader apparatus  10  is assembled to a transfer  22 ′ positioned along a conveyor  12  in a downstream direction from at least one other material transfer  22  positioned upstream along the conveyor. When the other upstream material transfer  22  is not loading material on the conveyor  12  and the retractable and extendable material loader apparatus  10  is loading material on the conveyor, the actuators  46  are operated to extend the lower tubular section  44  from the upper tubular section  42 . This positions the bottom opening of the lower tubular section  44  in close proximity to the conveying surface  14  of the conveyor  12 . Bulk material is then loaded onto the conveying surface  14  of the conveyor  12  through the upper tubular section  42  and the extended lower tubular section  44 . The positioning of the lower tubular section  44  in close proximity to the conveying surface  14  reduces the potential for spillage of the material as it exits the extended lower tubular section and contacts the moving conveying surface  14 . 
   When it is desirable to load material onto the conveying surface  14  from the other upstream material transfer  22 , the actuators  46  of the retractable and extendable material loader apparatus  10  are then operated to move the lower tubular section  44  upwardly to the retracted position relative to the upper tubular section  42 . This raises the lower tubular section  44  above the conveying surface  14  and provides adequate clearance for the material loaded onto the conveying surface  14  from the other upstream material transfer  22  to pass beneath the retractable and extendable material loader apparatus  10 . 
   Thus, the apparatus of the invention overcomes the problem of spillage of material from a moving conveying surface by a second material loader positioned along the conveying surface. 
   Although the apparatus of the invention has been described above by referring to a single embodiment of the invention, it should be understood that modifications and variations could be made to the apparatus without departing from the intended scope of the following claims.