Patent Publication Number: US-6991088-B1

Title: Conveyor belt cleaner assembly including blade support assembly

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates in general to material handling conveyors and, more particularly, to a construction for providing scalper blades located in engagement against a conveyor belt for cleaning debris from the conveyor belt. 
   2. Description of Related Technology 
   Transportation of a materials, such as materials in a mining operation, is often accomplished through use of a conveyor belt system. In use, material is loaded on the conveyor belt at a loading location and the conveyor belt carries the material to another location where the material is unloaded. During this process, some of the material may adhere to or otherwise accumulate on the surface of the conveyor belt, resulting in the material being carried back to the loading location. In being carried back, the material may drop off the conveyor, resulting in an undesirable accumulation of debris beneath the conveyor, or may remain adhered to the conveyor, potentially interfering with the continued operation of the conveyor. Accordingly, scalper blades are often located at the discharge end of the conveyor in order to scrape debris from the belt as the belt passes down to the return run of the conveyor. 
   Typically, the blades are formed of a polymer material, such as urethane or polyurethane, and therefor provide a degree of resiliency for permitting irregularities in the belt, such as splices, to pass while also engaging and removing debris. A mounting structure may be provided for the blades where the mounting structure is movably supported to bias the blades against the belt, and to reposition the blade edges as the blades wear down in order to maintain the blades in contact with the belt. In addition, the blades may be replaced when the blades have worn to the end of their useful life. Generally, the conveyor system must be taken out of operation for a period of time in order to perform servicing operations including adjustment and replacement of the blades. Accordingly, it is desirable to provide a scalper blade system in which the system adjustments are readily performed, and which provides for efficient replacement of the blades, while minimizing downtime to the conveyor system. 
   SUMMARY OF THE INVENTION 
   In one aspect of the invention, a scalper blade assembly is provided for use with a belt conveyor, the assembly comprising an elongate blade support member defining an elongate axis; at least one scalper blade supported on the blade support member for engagement with a conveyor belt, the at least one scalper blade including at least one elongate engagement member for engaging the support member; the support member including a support surface and passage for receiving the at least one engagement member; and a locking member located in the support member and movable relative to the support member, where movement of the locking member relative to the support member engages and disengages the at least one engagement member in locking engagement with the support member. 
   In another aspect of the invention, a scalper blade assembly is provided for use with a belt conveyor, the assembly comprising an elongate blade support member defining an elongate axis; a plurality of scalper blades supported on the blade support member for engagement with a conveyor belt, the scalper blades including elongate engagement members for engaging the support member; the support member including a support surface and passages for receiving the engagement members; and a locking member located in the support member and movable relative to the support member, where movement of the locking member relative to the support member simultaneously engages and disengages the engagement members in locking engagement with the support member. 
   Other features and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevational view of the discharge end of a conveyor system including a scalper blade assembly constructed in accordance with the present invention; 
       FIG. 2  is an end elevational view of the conveyor system illustrated in  FIG. 1 ; 
       FIG. 3A  is cross-sectional view of the scalper blade assembly; 
       FIG. 3  is a partially exploded view of a scalper blade assembly constructed in accordance with the present invention; 
       FIG. 4  is an exploded view of an adjustment unit for the scalper blade assembly; 
       FIG. 5  is a cross-sectional view of the adjustment unit for the scalper blade assembly; 
       FIGS. 6–8  are interior views of the gear plate portion of the adjustment unit illustrating three positions of the pawl for engaging the gear of the adjustment unit; 
       FIG. 9  is an exploded view of a blade support assembly; 
       FIG. 10  is an elevational view of a cam pin for the blade support assembly; 
       FIG. 11  is an end view of the cam pin for the blade support assembly; 
       FIG. 12  is a perspective view of a bearing cap for the blade support assembly; 
       FIG. 13  is a perspective view of the cam pin located in the bearing cap for the blade support assembly; 
       FIG. 14  is a side elevational view of a scalper blade; 
       FIG. 15  is a rear elevational view of the scalper blade of  FIG. 14 ; and 
       FIG. 16  is bottom plan view of the scalper blade of  FIG. 14 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 1 and 2 , an end portion of a material handling conveyor is illustrated including a pair of side plates  10 ,  12  mounting a conveyor roller  14  for supporting a discharge end portion of a conveyor belt  16 . A scalper blade assembly  18  is also mounted on the side plates  10 ,  12  at a location adjacent the conveyor belt  16  for engaging the conveyor belt at a location approximately midway between the top and bottom of the conveyor roller  14 , i.e., a three o&#39;clock position as seen in  FIG. 1 . The scalper blade assembly  18  is provided to remove debris from the discharge end of the conveyor belt  16  and prevent or reduce the carry-back of material along the lower run of the conveyor belt  16 . 
   Referring additionally to  FIG. 3 , the scalper blade assembly  18  comprises a blade support member  20 , illustrated as supporting a plurality of scalper blades  22 . The blade support member  20  is illustrated as an elongate member, and is supported for rotation about an elongate axis  24  of the blade support member  20  by a blade tension adjustment assembly, including adjustment units  26 ,  28 . The adjustment units  26 ,  28  are substantially similar units located at opposing ends of the blade support member  20  for providing an incrementally adjustable rotational position of the blade support member  20  and for providing a biasing tension to the scalper blades  22 , and are supported on the side plates  10 ,  12  by respective mounting sleeves  30 ,  32 . 
   Referring to  FIGS. 4 and 5 , the adjustment unit  26  is illustrated, it being understood that the adjustment unit  28  is of substantially similar construction, including components corresponding to those described below for the unit  26 . The adjustment unit  26  comprises a housing  34  including an actuator tube  36 , and a gear plate  38  rigidly attached to the actuator tube  36 . An input shaft  40  extends through a first end  42  of the housing  34 , and an output shaft  44  extends through a second end  46  of the housing  34  and is coupled to the input shaft by a resilient coupling  48 , preferably comprising a rubber coupling having a Shore A hardness of approximately  40  to  45 . The input shaft  40 , coupling  48  and output shaft  44  form a tensioning assembly  49 . In addition, an end seal  51  comprising a rubber seal is located on the second end  46  for closing off the housing  34  and preventing entry of contaminants into the housing. 
   The input and output shafts  40 ,  44  are supported for rotatable movement within the actuator tube  36  by respective bushings  50 ,  52 , preferably comprising bushings formed of an ultra high molecular weight polyethylene (UHMWPE) material. The input shaft  40  includes an input end  54  formed with a non-circular shape, such as a square shape, for engagement with a tool (not shown) for applying a torque force to the input shaft  40 . Torque force from the input shaft  40  is transmitted through the coupling  48  to the output shaft  44  and to the blade support member  20  supported on an output end  56  of the output shaft  44 . The output end  56  of the output shaft is formed with a non-circular shape, such as a square shape for cooperating with an opening of corresponding shape in the blade support member  20 . Engagement of the blades  22  against the conveyor belt  16  operates to resist rotation of the blade support member  20  toward the conveyor belt  16 , such that a resilient tension force is produced in the coupling member  48 , which operates to maintain a biasing force against the blades  22 . 
   The adjustment unit  26  is provided with a tension mechanism which is housed within the gear plate  38 . A gear  58  is rigidly fixed to the input shaft  40  and is located within a gear recess  60  of the gear plate  38 . A pawl  62  is located in a pawl recess  64  in the gear plate  38  and is supported on an actuator pin  66  extending through a bushing  68  in a passage  70  of the gear plate  38 . An outer end of the actuator pin  66  supports a pawl positioning lever  72  which is located against a spacing washer  74  for pivotal movement relative to the gear plate  0 . 38 . Pivotal movement of the positioning lever  72  moves the pawl  62  to one of a plurality of selectable positions relative to the gear  58 . A spring plunger  76  is mounted in the gear plate  38  and includes a casing  78  and a resiliently biased plunger portion  80  extending into the pawl recess  64  for engagement with a cam side of the pawl  62 . 
   Referring to  FIGS. 6–8 , the spring plunger  76  operates to locate the pawl  62  in one of three positions for controlling rotation of the gear  58  and the associated tensioning assembly  49  formed by the input shaft  40 , coupling  48  and output shaft  44 . The pawl  62  includes a first cam detent area  82 , a second cam detent area  84  and a third cam detent area  86  for engagement with the plunger portion  80  of the spring plunger  76 . When the lever  72  is pivoted to locate the first cam detent area  82  in engagement with the plunger portion  80 , a first pawl tooth  88  is located in engagement with the teeth  53  of the gear  58 , and a second pawl tooth  90  is located adjacent a stop wall  92  located at one side of the pawl recess  64 . The pawl  62  rotates in the clockwise direction, as seen in  FIG. 6 , when a force is applied to rotate the gear  58  in a forward counterclockwise direction, with the second pawl tooth  90  moving in a direction away from the stop wall  92  to permit the first pawl tooth  88  to move away from the gear  58  in a ratcheting action as the gear  58  rotates. The first pawl tooth  88  includes a curved or ramp-like surface  94  for facilitating movement of the gear teeth  53  past the first pawl tooth  88  during rotation of the gear  58  in the forward direction. When a force is applied to rotate the gear  58  in a reverse clockwise direction, a stop surface  100  on the second pawl tooth  90  engages against the stop wall  92  and a stop surface  96  on the first pawl tooth  88  engages against the gear teeth  53  to prevent rotation of the gear  58  in the reverse direction. 
     FIG. 7  illustrates the pawl position with the lever  72  positioned in a reverse position to locate the second cam detent area  84  engaged with the plunger portion  80 , such that the second pawl tooth  90  is located in engagement with the teeth  53  of the gear  58 , and the first pawl tooth  88  is located adjacent the stop wall  92 . The pawl  62  rotates in the counterclockwise direction, as seen in  FIG. 7 , when a force is applied to rotate the gear  58  in the reverse clockwise direction, with the first pawl tooth  88  moving in a direction away from the stop wall  92  to permit the second pawl tooth  90  to move away from the gear  58  in a ratcheting action as the gear  58  rotates. The second pawl tooth  90  includes a curved or ramp-like surface  98  for facilitating movement of the gear teeth  53  past the second pawl tooth  90  during rotation of the gear in the reverse direction. When a force is applied to rotate the gear  58  in the forward counterclockwise direction, the stop surface  96  of the first pawl tooth  88  engages against the stop wall  92  and the stop surface  100  on the second pawl tooth  90  engages against the gear teeth  53  to prevent rotation of the gear  58  in the forward direction. In the positions of the pawl  62  illustrated in  FIGS. 6 and 7 , the plunger portion  80  cooperates with the respective cam detent areas  82 ,  84  to resiliently maintain the pawl  62  in the selected position while permitting limited pivoting movement of the pawl  62  in response to passage of the gear teeth  53  during unidirectional ratcheting movement of the gear  58 . 
     FIG. 8  illustrates a neutral position of the lever  72  to position the third cam detent area  86  in engagement with the plunger portion  80 . In the neutral position, both the first and second pawl teeth  88 ,  90  are located out of engagement with the gear  58 , such that the gear  58  and associated tensioning assembly  49  may freely rotate in either direction. 
   It should be noted that in the above-described adjustment structure, other elements equivalent to the gear  58  and pawl  62  may be provided, such as member including detent areas or other structure for engaging with the pawl  62  or a similar element. Referring to  FIGS. 4 and 5 , the gear recess  60  and pawl recess  64  in the gear plate  38  are covered by a clamping plate  102 , with a rubber seal  104  located between the gear plate  38  and the clamping plate  102 . Threaded studs  106  are rigidly fastened in the gear plate  38  and extend through apertures  108  in the clamping plate  102 , and the clamping plate  102  is held in position by nuts  110  engaged on the ends of the studs  106 . 
   During a blade tensioning operation, the end  54  of the input shaft  40  is rotated in an appropriate direction, such as counterclockwise as viewed in  FIG. 6 , to pivot the blade support member  20  in a direction to bias the blades  22  against the conveyor belt  16  with a desired tension. In such a tensioning operation, the lever  72  is positioned in the forward tension position to engage the first pawl tooth  88  with the teeth  53  of the gear  58 . In addition, during the tensioning operation, the nuts  110  are loosely engaged on the ends of the studs  106  such that the clamping plate  102  and seal  104  are loosely engaged adjacent the gear plate  38 . 
   When the gear  58  has been rotated to obtain the desired tensioning force biasing the blades  22  against the conveyor belt  16 , the nuts  110  are tightened to cause an inner surface  112  of the clamping plate  102  to frictionally engage and press against a front face  114  of the gear  58  to press a rear face  116  of the gear  58  against an inner surface  118  of the gear recess  60 . 
   Accordingly, the gear  58  is clamped between the clamping plate  102  and the gear plate  38  to clamp the position of the input shaft  40  such that during operation of the blades  22  to scape debris from the conveyor belt  16 , shock forces from the blade support  20  will be transferred through the tensioning assembly  49  to the gear  58  and directly from the gear  58  to the housing  34  of the adjustment unit  26 . Thus, the adjustment unit  26  comprises two locating mechanisms in which one provides for incremental adjustment of tension on the blades  22  and the other provides a locking function for maintaining the selected adjustment position. In this manner, the pawl  62  and cooperating teeth  53  of the gear  58  are relieved of carrying a substantial portion of forces imparted to the blades  22  and transmitted between the support member  20  and the housing  34 . 
   It should be understood that substantially identical adjustment units  26  and  28  may be provided on either side of the support member  20  for exerting a biasing force to tension the blades  22  against the conveyor belt  16 . For example the adjustment unit  26  may be provided on the left side of the conveyor belt  16  and the substantially identical second unit  28  may be provided on the right side of the conveyor  16 . However, the positions of the lever  72  for forward and reverse rotation of the gear  58  in the second unit  28  will be reversed, such that the lever  72  will be moved to engage the plunger portion  80  in the second cam detent area  84  for rotation in a forward direction for tensioning the blades  22 , and to engage in the first cam detent area  82  to provide ratcheting movement of the gear  58  in the reverse direction. 
   Referring to  FIGS. 3 ,  3 A and  9 , the blade support member  20  comprises a tubular upper member  120  rigidly attached, such as by welding, to a tubular lower member  122 . The upper member  120  is illustrated as a square tubular member having a plurality of upper holes  124  in an upper support surface  126 , and a plurality of lower holes  128  formed in a lower side  130  and aligned with the upper holes  124 . The lower member  122  is illustrated as a square tubular member having an upper side  132  formed with a plurality of holes  134 , and attached adjacent the lower side  130  of the upper member  120 , with the holes  134  aligned with the upper and lower holes  124 ,  128  of the upper member  120 . The holes  124 ,  128  and  134  have substantially the same diameter. The upper member  120  defines an inner circumference which is sized to fit over the output ends  56  of the output shafts  54  for mounting the support member  20  on the adjustment units  26 ,  28 . The upper member  120  and output ends  56  are maintained in associated with each other by fasteners  131  extending through aligned holes  133  and  135  in the upper member  120  and output ends  56 , respectively. 
   A locking member  136  is located within the lower member  122  and, in the present example, is illustrated as a tubular member of circular cross-section. The locking member  136  includes a plurality of openings  138  axially aligned with the holes  124 ,  128  and  134 . The openings  138  are formed as key hole openings, where each opening comprises an enlarged, generally circular portion  140  having a diameter substantially similar to the diameter of the holes  124 ,  128  and  134 . An elongate slot portion  142  is located extending circumferentially from each of the circular portions  140 , where the slot portions  142  define a width less than the diameter of the circular portions  140 . 
   Referring additionally to  FIGS. 10 and 11 , the locking member  136  is located for rotation within the lower member  122  by cam pins  144 . The cam pins  144  have an inner end  145  located within respective ends of the locking member  136  and the cam pins  144  are held in place by pins (not shown) extending through holes  148  in the cam pins  144  and aligned holes  146  in the locking member  136 . Bearings  150  are positioned over a central portion  152  of the cam pins  144 , and the assembled cam pins  144  and bearings  150  are located within bearing caps  154  ( FIGS. 12 and 13 ), where the cam pins  144  are rotatable relative to the bearing caps  154 . The bearing caps  154  are shown as including generally square end portions  156  which are positioned within the ends of the lower member  122  to thereby provide support for the locking member  136 . 
   Referring to  FIG. 12 , a bearing cap  154  is illustrated for use on either side of the support member  20 . It can be seen that the end portion  156  defines a circular opening  158  through which the cam pin  144  passes. The opening  158  is offset relative to two adjacent sides of the bearing cap  154 . Specifically, the position of the opening  158  is offset closer to a side L of the bearing cap  154  and is additionally offset closer to a side R of the bearing cap  154 . When the bearing cap  154  is mounted in the left side of the lower member  122 , the side L is positioned facing horizontally to the rear, i.e., adjacent a rear side  160 , of the support member  122 . When the bearing cap  154  is mounted in the right side of the lower member  122 , the side R is positioned facing horizontally adjacent a rear side  160  of the support member  122 . Thus, the openings  158  on the left and right side of the lower member  122  is offset toward the upper side  132  and the rear side  160  of the lower member  122 . 
   Referring to  FIG. 11 , the central axis of the inner end  145  of each cam pin  144  is offset or eccentric relative to the central axis of the central portion  152  of the cam pin  144 , such that rotation of the cam pin  144  within the opening  158  operates to move the inner end  145 , and thus the locking member  136 , in a direction transverse to an elongate axis of the locking member  136 . Specifically, an outer end  162  of the cam pin  144  is rotatable through 90° of movement, which movement will move the locking member  136  in a transverse direction away from the upper side  132  of the lower member  122 . 
   As seen in  FIG. 12 , the bearing cap  154  is preferably provided with an indicia indicating the side of the bearing cap  154  to be placed in the rearward facing position and thereby facilitate use of a common bearing cap  154  on either side of the lower member  122 . For example, the side L of the bearing cap  154  may be provided with an “L” and the side R of the bearing cap  154  may be provided with an “R” as indicia indicating the proper orientation of the bearing cap  154  on the lower member  122 . Similarly, in order to locate the eccentric inner end  145  of the cam pin  144  in the correct orientation within each respective bearing cap  154 , opposing flat sides  164 ,  166  of the outer end  160  are provided with indicia. For example, the flat sides  164  and  166  may be provided with the indicia “L” and “R”, where the left cam pin  144  is located with the “L” facing upwardly in a first, non-operational position and is located aligned with the “L” side of the bearing cap in a second, operational position of the cam pin  144  (see  FIG. 13 ). Similarly, the cam pin  144  on the right side of the lower member  122  will be located with the “R” indicia facing upwardly in a first, non-operational position of the cam pin  144 , and will be located aligned with the “R” side of the right side bearing cap  154  in a second, operational position of the cam pin  144 . 
   The cam pin  144  is provided with a hole  168  located adjacent the outer end  160 , where the cam pin hole  168  is aligned with one of two through holes  170  or  172  in the bearing cap  154  when the cam pins  144  have been rotated to the operational position on the left and right side, respectively, of the lower member  122 . Further, when the cam pins  144  are located in the operational position, a blade locking pin  174  ( FIG. 3 ) is inserted through the aligned holes  168  and  170  or  172  to lock the locking member  136  in the operational position. 
   Referring to  FIGS. 14–16 , the scalper blades  22  each comprise a body  176  formed of an elastomeric material, preferably rubber, and elongate engagement members, illustrated as a pair of rigid metal engagement pins  178  extending from a lower side of the body  176 . The engagement pins  178  are formed with a diameter which permits the pins  178  to pass in a close tolerance fit through the holes  124 ,  128  and  134  in the upper and lower members  120 ,  122  of the support member  20 . The engagement pins  178  include a groove area  180  defining an upwardly facing land surface  182 . Each scalper blade  22  is located on the support member  20  with a lower surface  184  of the scalper blade  22  positioned on the support surface  126  and lower ends of the engagement pins  178  extending into the locking member  136 . In an installation operation for placing the scalper blades  22  on the support member  20 , the locking member is rotated to position the generally circular portions  140  in alignment with the holes  124 ,  128  and  134 , and insertion of the lower ends of the engagement pins  178  though the locking member  136  positions the groove areas  180  adjacent the circular wall of the locking member  136 . 
   The elongate slot portions  142  of the locking member  136  define a width less than the diameter of the engagement pins  178 , but large enough to permit passage of the groove areas  180  though the slot portions  142 . The scalper blades  22  are locked in position by rotation of the cam pins  144  from the non-operational position to the operational position, causing the locking member  136  to rotate and engage the slot portions  142  of the locking member  136  with the groove areas  180  of the engagement pins  178 , such that the land surfaces  182  face and engage an inner wall surface of the locking member  136  to prevent removal of the scalper blades  22  from the support member  20 . The length of the openings  138  in the locking member is such that only approximately 90° rotation of the locking member  136  is permitted from the non-operational to the operational position. In addition, as rotation of the cam pins  144  also results in transverse movement of the locking member  136  away from the support surface  126 , the lower surface  184  of each scalper blade  22  is drawn downwardly into tight engagement against the support surface  126 . 
   It should be understood that the engagement pins  178  engage within the holes  124 ,  128  and  134  (see  FIG. 3A ) in a close tolerance fit to provide a structure for holding the engagement pins  178  at longitudinally spaced locations along the pins  178  for resisting lateral loads applied against the scalper blades  22  during use in association with the conveyor belt  16 , which structure is separate from the structure of the locking member  136  for maintaining the blades  22  in engagement on the support member  20 . 
   It should also be noted that the structure for locking the scalper blades  22  in place on the support member  20  enables all of the blades  22  to be locked or unlocked on the support member  20  simultaneously through movement of a single member, i.e., through rotation of the locking member  136 . The present structure facilitates a reduction in maintenance time associated with installation and removal of the blades  22 . 
   Referring to  FIG. 16 , the lower surface  184  of each scalper blade  22  is formed with seal portions comprising ribs  186  extending from the lower surface  184  for engaging and forming a seal around the engagement pins  178  and holes  124  in the upper surface  126 . In addition, front and rear flaps or skirts  188 ,  200  extend from front and rear sides  202 ,  204  of the scalper blade  22  for engaging over front and rear side edges  206 ,  208  of the upper member  120 . The ribs  186  and skirts  188 ,  200  function to seal out contaminants from entering the interior of the upper and lower members  120 ,  122  through the holes  124 , and thereby protects the locking member  136  from being affected by contaminants. 
   The scalper blade body  176  includes a metal plate  210  located within a lower, base portion  212  of the body  176 . The engagement pins  178  are attached to the plate  210 , preferably by welding, and the plate  212  is molded within the base portion  212  during formation of the scalper blade  22  to provide a firm attachment structure between the engagement pins  178  and the elastomeric material of the blade  22 . 
   An upper portion  214  of the scalper blade body  176  angles forwardly from the base portion  212 , and the front and rear sides  202 ,  204  converge toward each other in a direction toward a blunt engagement edge  216 . The base portion  212  is formed as a wide block-like structure, having the front and rear sides  202 ,  204  formed as substantially parallel vertical surfaces, for providing a generally rigid lower support for the elongated upper portion  214 . In addition, the rear side  204  of the upper portion  214  includes an indicia, such as a rib  218 , indicating a wear point on the scalper blade  22  when the blade  22  should be replaced. 
   In use, the adjustment units  26 ,  28  may be operated to pivot the scalper blade support member  20  forward, and to tension the scalper blades  22  against the conveyor belt  16 . A predetermined torque force applied to the blades  22  through the support member  20  may be provided through the resilient couplings  48  which will elastically deform as tension in applied through the input shaft  40  to the output shaft  44 . The resilient material of the blades  22  and the resilient material of the couplings  48  provide two resilient structures for absorbing shock loads applied to the blades  22 . 
   In addition, when it is desired to provide maintenance to the blades  22 , the pawl positioning lever  72  may be moved to the neutral position to permit free pivotal movement of the support member  20  away from the conveyor belt  16 . It should also be noted that during maintenance involving release or locking of the blades  22  by the locking member  136 , the pawls  62  may be located to a position engaging the gear  58  to limit the support assembly  20  to a stationary position and thereby facilitate application of a torque force for turning the locking member  136 . 
   While the form of apparatus herein described constitutes a preferred embodiment of this invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.