Abstract:
Two embodiments of a conveyor belt scraper are disclosed herein, with each including an inflatable bladder urging a scraper blade against the belt when the bladder is inflated, thereby providing even and uniform pressure for the blade against the belt. In a first embodiment, the scraper blade bears against a free section of the belt, with a guide extending across the opposite side of the belt to support the belt. The bladder is enclosed in a housing, with a blade slot formed in the upper portion thereof. A single belt scraper blade is placed within the housing and extends through the blade slot. A second embodiment urges the blade edge against the belt as the belt passes over a roller on the conveyor line. The blade has a double concave arcuate underside, with the two concave curvatures defining a pivot fulcrum therebetween. The inflatable bladder resides in the concave curvature opposite the scraping blade edge, and urges the blade edge against the belt as the bladder is inflated. In both embodiments, the bladder, housing, and blade have a length extending essentially the entire width of the conveyor belt with which they are installed and used. The blade is preferably formed of a relatively soft material, such as a urethane plastic, to minimize scoring and cutting of the belt. The blade is formed of a relatively thick and deep sheet of material, for reducing bending effects thereto. The bladder may be inflated with any compatible pneumatic or hydraulic fluid, as desired.

Description:
REFERENCE TO RELATED PATENT APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/107,020 filed on Nov. 4, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to industrial cleaning mechanisms and devices, and more specifically to an apparatus for applying a scraping blade to a conveyor belt for scraping material therefrom during the operation of the belt. The present invention provides a means for applying an even, uniform scraper pressure across the entire width of the belt, thus eliminating uneven scraping due to sag of the scraper blade. A lower scraper pressure is also required, allowing the use of a relatively soft scraper blade material to reduce greatly the wear and tear on the belt. Two different embodiments are disclosed herein, with the first embodiment directed to a secondary type belt wiper or cleaner, which operates across a free span of the belt, and the second embodiment directed to a primary type belt wiper, which operates across the belt as it passes over a roller. 
     2. Description of the Related Art 
     Conveyor belts are used in many different industries (mining, maritime, food processing, etc.) for the conveyance or transfer of raw materials or finished goods from one point to another. Such conveyors, particularly when used for raw materials, generally become contaminated with the materials and require the removal of such material buildup from time to time, in order to avoid contaminating or jamming the equipment. 
     Accordingly, various devices have been developed for cleaning or scraping down the surface of a conveyor belt. While most such devices provide some moderate success, it must be considered that most were developed for relatively narrow conveyor belts, having a width on the order of about three feet. As such, there is relatively little lateral sag across the belt, and/or across the laterally disposed cleaner or scraper blade. However, with the development of relatively wider conveyor belts for greater productivity, such earlier devices are generally incapable of providing a thorough cleaning or scraping action across the entire width of the belt. Many such belts now have widths of seven to eight feet, and while earlier scrapers have been scaled up to reach across such relatively wide belts, they do not provide the even pressure across the entire width of the belt which is necessary for thorough cleaning of the belt. 
     Moreover, many such earlier scrapers utilize relatively thin metal scraping blades. This, along with the relatively high scraping pressure required in order to assure scraping action across the entire width of the belt, can result in uneven pressures and possible cutting or scoring of the belt, leading to further difficulty in cleaning the belt and early replacement of the belt. 
     Accordingly, a need will be seen for a cleaner or scraping device for conveyor belts, which applies an even and uniform pressure across the entire belt by means of fluid activation. The device also includes a single, relatively wide scraper blade of relatively soft material, in order to impart such even and uniform pressures across the entire width of the belt and to avoid cutting or grooving the belt during the scraping operation. The depth of the blade is sufficient to preclude significant distortion or bending thereof, with all forces imparted between the conveyor belt and the scraper blade being evened out by the fluid actuation of the blade. A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below. 
     U.S. Pat. No. 4,696,388 issued on Sep. 29, 1987 to Donald L. Stoll, titled “Conveyor Belt Scraper Blade Assembly With Contoured Surface,” describes a scraper having a convex transverse contour, for applying scraping pressure across the center of a conveyor belt having a concave lateral shape due to use and the belt support system. The scraper blades are formed of relatively soft materials (i.e., different rubber durometers), but the Stoll device does not apply an even pressure completely across the belt if the belt does not precisely match the contour of the blade of the device. This is particularly true for a primary type belt cleaner, where the scraper spans the belt across a supporting roller for the belt, which does not allow the belt to flex. Stoll does not disclose any fluid pressure actuating means for his scraper assembly, as is provided by the present invention. 
     U.S. Pat. No. 5,113,999 issued on May 19, 1992 to Reiner Zeppenfeld, titled “Positionable Doctor Blade,” describes an apparatus for applying pressure to an opposed pair of doctor blades or scrapers each bearing against one of a pair of opposed belts on corresponding rollers, i.e., primary wipers or blades. The mechanism used to apply pressure to the blades may utilize fluid pressure (i.e., hydraulic or pneumatic), but the pressure actuator operates only a single arm which is in turn connected between the two blades to apply equal pressure to the two blades. Zeppenfeld does not provide any means for applying even pressure along the entire length of a single blade, as each of his single blades is held in place in a rigid mechanical linkage. Zeppenfeld does not utilize an inflatable bladder disposed transversely along the entire back of the blade for applying uniform pressure to the entire blade across the entire width of the conveyor, as provided by the present invention. 
     U.S. Pat. No. 5,213,197 issued on May 25, 1993 to Toyoshige Mohri, titled “Belt Cleaner For Conveyor,” describes a fluid activated scraper blade array. A transverse bladder is used to apply pressure to a series of blades, which in turn apply scraping pressure to the surface of the conveyor. The blades are tied together by a flexible cover sheet secured to each side thereof. Thus, each blade is somewhat independent of every other blade, particularly for blades which are somewhat laterally separated from one another. In contrast, the present conveyor scraper mechanism uses a single scraper blade which extends essentially the entire width of the conveyor belt to provide a uniform pressure completely thereacross. Also, Mohri utilizes a relatively hard and narrow, sharp material for his blade segments, as opposed to the relatively soft plastic single blade element of the present invention. 
     U.S. Pat. No. 5,248,026 issued on Sep. 28, 1993 to Allen J. Morefield, titled “Conveyor Belt Scraper Mechanism,” describes a fluid actuated mechanism having a single fluid cylinder which in turn actuates an arm which rotates a blade toward or away from the belt. The resulting action is somewhat related to that described in the &#39;999 U.S. patent to Zeppenfeld, described further above, in that the linkage which applies the scraping pressure to the blade is mechanical. Moreover, Morefield utilizes a relatively hard metal blade, unlike the relatively soft plastic material used for the blade of the present scraper invention. Morefield does not disclose an inflatable bladder extending essentially the entire 
     U.S. Pat. No. 5,372,244 issued on Dec. 13, 1994 to Normand J. Morin, titled “Conveyor Belt Scraper,” describes a fluid expelled plastic scraper blade. The blade is coiled within a chamber, and water under high pressure is forced into the chamber to push the blade from the chamber to compensate for blade wear. Morin does not utilize an inflatable bladder to apply continuous even pressure to the blade against the conveyor belt, as provided by the present invention. 
     U.S. Pat. No. 5,622,249 issued on Apr. 22, 1997 to Normand J. Morin, titled “Conveyor Belt Scraper,” describes a system essentially like that described immediately above in the &#39;244 U.S. patent to the same inventor. The &#39;249 U.S. patent also describes a suspension system for the blade and blade housing, which has no bearing on the present belt scraper invention. 
     U.S. Pat. No. 5,722,528 issued on Mar. 3, 1998 to Troy D. Dolan, titled “Method And Apparatus For Cleaning Conveyor Belts,” describes a device having a transverse support for a plurality of individual blade lift cylinders and corresponding plurality of blades. The Dolan device is exceedingly complex, as it requires a myriad of separate pressure and return lines to feed all of the cylinders of the device. In contrast, the present invention utilizes a single fluid lift mechanism comprising a flexible bladder (not a rigid cylinder), which in turn applies pressure to the edge (in one embodiment) or to the opposite side (in a second embodiment) of a single, relatively wide scraper blade formed of a relatively soft material (i.e., plastic). 
     Finally, International Patent Publication No. 94/08875 published on Apr. 28, 1994 to Normand J. Morin, titled “Conveyor Belt Scraper,” describes a scraper comprising a sheet of flexible plastic which is coiled within a pressurized cylinder. One edge of the plastic extends from a slot in the cylinder, and is forced from the slot and against the conveyor belt by pressurizing the cylinder. The &#39;875 International Patent Publication to Morin is based upon a British patent application, upon which the &#39;249 U.S. patent to the same inventor (discussed further above) is based. The &#39;875 International Patent Publication is also closely related to the &#39;244 U.S. patent to the same inventor, also discussed further above. The same distinctions are felt to apply here. 
     None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. 
     SUMMARY OF THE INVENTION 
     The present invention comprises a conveyor belt scraper for cleaning or scraping materials from a conveyor belt. The present scraper comprises a transversely disposed inflatable bladder enclosed within a fixed elongate housing, which bears against a single piece blade element to urge the blade element against the belt. In a first embodiment, the housing has a blade slot formed in the upper portion thereof. The bladder and housing are essentially the width of the conveyor belt to which the present device is applied. A relatively thick and deep blade extends essentially the entire length of the slot, with the blade having a length sufficient for extending the entire width of the conveyor belt. When the bladder is inflated, it applies pressure to the lower edge of the blade, forcing the blade upwardly from the slot to bear against the overlying conveyor belt, thereby scraping any accumulated material from the belt. The blade is preferably formed of a plastic material to avoid significant abrasion to the belt. The bladder may be inflated with any suitable fluid (i.e., pneumatic, hydraulic, etc.). A guide is also provided for applying pressure to the opposite side of the belt, against the scraper. 
     In a second embodiment, the blade has a cross section having a convex arcuate shape with two concave arcuate shapes inwardly disposed of the convex shape. The two concave arcuate shapes define a fulcrum therebetween, with the blade pivoting on an elongate axis through the fulcrum. The fluid tube is positioned beneath the concave arc opposite the conveyor belt. When the tube is inflated, it lifts that side of the blade, urging the opposite edge of the blade against the belt. 
     Accordingly, it is a principal object of the invention to provide an improved conveyor belt scraper utilizing an elongate inflatable bladder transversely disposed to the belt, with the bladder extending essentially the width of the belt. 
     It is another object of the invention to provide an improved belt scraper incorporating an elongate housing for the bladder, with the housing having an elongate cleaning blade slot formed in the upper portion thereof. 
     It is a further object of the invention to provide an improved belt scraper incorporating a cleaning and scraping blade formed of a single piece of thick plastic material and extending essentially the entire width of the housing slot, with the blade being forced upwardly against the belt due to the inflation of the bladder. 
     An additional object of the invention is to provide an improved belt scraper including a guide disposed across the opposite side of the belt from the scraper blade, for applying pressure to the belt against the blade. 
     Still another object of the invention is to provide an improved belt scraper including a mounting frame for securing the scraper to the conveyor belt structure. 
     Yet another object of the invention is to provide an improved belt scraper having a second embodiment in which the scraper blade comprises a convex arcuate shape with two concave arcuate shapes inwardly disposed of the convex shape defining a fulcrum therebetween, with the blade pivoting on an elongate axis through the fulcrum. The fluid tube is positioned beneath the concave arc opposite the conveyor belt and when inflated, it lifts that side of the blade, urging the opposite edge of the blade against the belt. 
     It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 
    
    
     These and other objects of the present invention will become apparent upon review of the following specification and drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partially broken perspective view of a first embodiment of the present belt scraper, showing various details thereof. 
     FIG. 2 is an end elevation view in section of the belt scraper apparatus of FIG. 1, showing the deflated and inflated shapes of the bladder therein and corresponding positions of the scraper blade. 
     FIG. 3 is a schematic end view of prior art means for scraping a conveyor belt. 
     FIG. 4 is a schematic view of a fluid system which may be used to actuate the inflatable bladder and blade of the present scraper. 
     FIG. 5 is a broken away perspective view of a second embodiment of the present conveyor belt scraper, showing the mechanism and operation thereof. 
     FIG. 6 is an end elevation view in section of the belt scraper apparatus of FIG. 5, showing the actuation of the scraper blade by the inflation of the fluid bladder. 
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention comprises various embodiments of a conveyor belt scraper for scraping and cleaning material residue from a conveyor belt, as used in various industries (maritime, mining, food processing, etc.). As conveyor belts convey materials thereon, particularly loose raw materials, such materials contaminate the belt surface and build up on the surface at least to a certain extent. This is particularly true of wet or damp materials, which tend to cling to the belt surface. 
     Accordingly, the present belt scraper provides a means of continually cleaning such residue from the outer or working surface of the belt as the belt travels about its run during operation. FIG. 1 provides a perspective view of a first embodiment of the present conveyor belt scraper assembly (a “secondary” type belt scraper), indicated by the reference numeral  10  throughout the drawings. The present belt scraper assembly may be constructed to any practicable width, depending upon the width of the conveyor belt to which it is applied, and is accordingly shown with its center portion broken away to indicate its indeterminate width. 
     The present conveyor belt scraper  10  generally comprises an elongate housing  12 , which is positioned transversely to the conveyor belt C. (The conveyor belt C is shown in broken lines in FIG. 1.) The housing  12  has a length L which is at least equal to the width W of the conveyor belt C, or perhaps slightly longer in order to provide the necessary length to house the belt scraper components described further below. 
     The housing  12  includes an upper portion  14  with a single elongate scraper blade slot  16  formed therein. The slot  16  has a width  18  which provides sliding clearance for a corresponding single, elongate scraper blade  20  installed therein, with the blade  20  also having a thickness  18  substantially the same as the width of the slot  16  and a scraper length S substantially the same as the slot width S. The housing  12  also includes a hollow interior  22 , with a single, elongate inflatable bladder  24  being housed therein. The bladder  24  preferably has a length substantially equal to the length of the interior of the housing  12 , and substantially fills the entire volume of the interior  22  of the housing  12  when the bladder  24  is inflated. 
     The housing  12  is mounted to an elongate base  26  (channel, or other suitable structure) which extends transversely beyond the width of the housing  12  and the conveyor belt C to which the present invention is applied. An end plate  28  serves to close the housing  12  and base  26  structure at each end thereof. (Only one end plate  28  is shown in FIG. 1, but it will be understood that the conveyor scraper  10  of the present invention is symmetrical.) 
     The base  26  extends between opposite end fixtures  30 , with the two end fixtures being essentially identical to one another. These end fixtures  30  serve to attach the scraper assembly  10  to a conveyor belt structure (not shown). Each fixture  30  is formed of a panel  32  of sheet metal or other suitable material, with each panel  32  having an angle  34  secured along opposite edges thereof. The angles  34  provide for the adjustable attachment of a hold down rod or guide  36  by means of fittings  38  which may be adjustably installed along any of the angles  34  as desired. The guide  36  includes a generally cylindrical outer sleeve  40  formed of a relatively soft material (e.g., urethane plastic, or other suitable material) in order to avoid damage to the inner surface of the conveyor belt against which it is deployed. Each of the fixtures  30  also includes means for attaching the assembly  10  to the adjacent conveyor line structure, as with the pair of clamps  42  provided at the upper end of each of the end fixtures  30  to secure about the conveyor structure. Handle means  44  may also be provided on each fixture  30 , if so desired. 
     FIG. 2 provides a cross sectional elevation view of the housing assembly of the present belt scraper  10 . In FIG. 2, the cross sectional shape of the housing  12  is clearly shown, with its relatively wide lower portion including the interior portion  22  for containing the inflatable bladder  24 . The upper portion  14  has a gabled shape, narrowing to the scraper blade slot  16  with its substantially vertical walls  46 , which serve as guides for the sliding extension and retraction of the scraper blade  20  therebetween. 
     The inflatable bladder  24  has a normal, deflated configuration generally as shown by the cross hatched solid line condition of FIG. 2, with a more cylindrical shape when inflated, as indicated by the circular broken line within the housing interior  22  in FIG. 2. A bladder having a 4.5 inch diameter when inflated, will deflate to a thickness of about 0.5 inch, thus providing a lift of four inches for the scraper blade  20  installed thereabove. The present belt scraper  10  may utilize a conventional inflatable bladder  24 , such as manufactured by Merriman Products, Inc. under the trade name “Windjammer”™. These bladders may be provided in any practicable length, as desired. Other makes, models, and configurations of inflatable bladders may be used as the actuation means of the present belt scraper  10 , if so desired. Such bladders may use pneumatic inflation means (air or other pressurized gases) or hydraulic inflation means (water, hydraulic fluid, etc.) as desired. 
     The scraper blade  20  is formed of a relatively wide piece of material, with the width being oriented in the vertical direction and defined by a lower bladder contact edge  48  and opposite upper conveyor belt scraper edge  50 . The width or depth of the blade  20  is preferably sufficient to extend at least slightly above the upper end of the slot  16  of the housing  12  when the blade  20  is resting upon the deflated bladder  24 , as shown in solid lines in FIG.  2 . Thus, when the bladder  24  is inflated, the blade  20  will raise sufficiently for the scraper edge  50  to contact the overlying conveyor belt and scrape any substantial material residue therefrom. 
     Preferably, the blade  20  is formed of a relatively soft, nonmetallic material, such as the urethane plastic of which the guide sleeve  40  is formed. This results in a relatively long life for the blade  20 , while also protecting the belt from excessive wear and abrasion. As noted above, the blade  20  preferably has a height or depth of several inches (about six or seven inches, although this may be adjusted as required, depending upon the specific belt configuration to which the present invention is applied, and the specific size of the inflatable bladder used.). This depth provides substantial rigidity for the blade  20 , which along with the even and uniform pressure provided by the inflatable bladder  24  during the belt scraping operation, provides even and uniform pressure across the entire conveyor belt, regardless of its width. 
     The belt hold down guide  36  and its sleeve  40  also serve to apply an even and continuous pressure on the opposite, inner side of the belt from the scraper blade, thus further providing even and uniform scraping action of the belt. Many belts used in today&#39;s industries have a width of six, seven, or even eight feet, and the rigidity of the scraper blade  20  due to its depth, along with the uniform pressure provided by the bladder  24  and opposing pressure of the guide rod  36 , result in an extremely uniform scraping action by the present belt scraper assembly  10 . As a result, the present belt scraper  10  requires relatively low inflation pressures for the bladder  24  in order to provide uniform and consistent scraping action, on the order of only about three pounds per square inch, as opposed to other systems requiring much higher pressures. 
     FIG. 3 provides a schematic end elevation view in section of a prior art belt scraping apparatus A, in which all of the lifting pressure for the scraper bar B is provided at each end of the scraper. In such prior art systems, some form of scraper lifting or pressure means, such as the springs D shown, or pneumatic or water inflated bags, etc., are provided at each end to apply pressure to the scraper bar B against the conveyor belt C 1 . As can be seen in FIG. 3, the lack of even and uniform support of the scraper bar B across the belt C 1 , particularly in the center area, results in the scraper bar B sagging and failing to make good contact with the conveyor belt C 1 . This results in inefficient cleaning of the belt C 1 , and/or a need to increase the pressure of the lifting means D. Such higher scraping pressures directed mostly to the edges of the belt C 1 , result in relatively rapid wear of the scraper bar B, and also to the belt C 1 . 
     FIG. 4 provides a schematic view of an exemplary operating system for the present belt scraper  10 . A pressure source  52  (pneumatic or hydraulic) is provided to supply operating pressure to the inflatable bladder of the belt scraper  10 . The pressure source  52  may be of any suitable conventional type, e.g., an electric motor powering an air or hydraulic pump, etc. Pressurized fluid (air or other gas, hydraulic fluid, etc.) passes from the pressure source  52  to a pressure regulator  54 , which reduces the pressure (if reduction is required) to the desired value before the fluid continues to the inflatable bladder of the belt scraper  10 . 
     The regulator  54  may be controlled by an operator as desired, with the regulator  54  being opened to admit the pressurized fluid into the bladder of the belt scraper  10  when belt cleaning or scraping is desired. When pressure is admitted to the bladder, the bladder inflates, raising the scraper blade to engage the outer surface of the belt and scrape any material residue therefrom. When scraping action is no longer needed, the pressure regulator  54  is closed (or the pressure source  52  is shut down) to relieve pressure in the system. 
     In order to relieve any residual pressure in the system, a relief valve  56  is provided in the return line to the pressure source  52 . The relief valve  56  may communicate with the suction side of the pressure source in order to provide positive deflation of the bladder of the belt scraper  10 , or may return fluid to a tank or reservoir, relying upon the weight of the scraper blade to deflate the underlying bladder. 
     FIGS. 5 and 6 illustrate a second embodiment of a “primary” type of belt cleaner or wiper, designated by the reference numeral  60 . Such primary wipers have a blade which bears against the conveyor belt C as it passes over a roller R or the like, rather than bearing against a portion of the free span of the belt C. In this manner, no hold down rod extending across the back of the belt C and opposite the scraper blade is required, as the roller R serves this function of backing up the belt C. 
     The primary belt wiper or scraper assembly  60  of FIGS. 5 and 6 includes a blade which is urged against the conveyor belt by an inflatable bladder, essentially as in the secondary wiper or scraper assembly of FIGS. 1 and 2 discussed further above. However, rather than the bladder applying pressure directly beneath the edge of the scraper blade and compressing the blade between the bladder and the conveyor belt, the system  60  of FIGS. 5 and 6 utilizes a lever principle to rock the blade against the belt. 
     An elongate bladder support  62 , comprising a conventional steel I beam having opposed flanges  64  with a web  66  extending between the flanges  64  and a length at least somewhat greater than the width of the conveyor belt C, provides support for the inflatable bladder  68  which extends substantially the width of the conveyor belt C and nests along the web  66  and between the two flanges  64  along one side of the support  62 . (The flanges  64  and web  66  are more clearly shown in FIG. 6 of the drawings.) The bladder support  62  is in turn held at each end thereof by opposed first and second support mounts  70  and  72 , which are in turn bolted or otherwise immovably affixed to the conveyor line structure or frame members F. (The first mount  70  is shown in FIG. 5, with the second mount  72  being shown in FIG. 6 of the drawings.) 
     The two mounts  70  and  72  are mirror images of one another, and provide for the adjustably pivotable mounting of the transverse mounting (i.e., parallel to the axis of the conveyor roller R) of the bladder support  62  therebetween. Each support  70  and  72  comprises a base  74  (visible only in FIG. 5) which is bolted or otherwise immovably affixed to the conveyor line structure or frame F, with a fixed support plate  76  extending upwardly therefrom. Each support plate  76  has a rotatably adjustable support beam attachment plate  78  mounted thereon, by means of a concentric pin or rod  80  (shown in FIG. 5) which extends from each support beam attachment plate  78  and through a hole or passage in the corresponding support plate  76 . 
     A series of radially displaced index holes or passages  82  (shown in FIG. 5) is provided in each support plate  76 , with a single locking hole or passage provided through each rotatable support beam attachment plate  78 . The plates  78  are rotatably adjusted relative to the fixed support plates  76 , with a locking bolt or pin  84  (FIG. 5) being placed through the single passage of each rotatable plate  78  and through a corresponding one of the index passages  82  of the support plates  76 , to fix the support beam  62  angularly as desired relative to the conveyor C and roller R. 
     The bladder  68  is retained along the side of the beam support member  62  by means of a pin  86  extending from each end of the bag  68 , which rides in a slot  88  in a bag or bladder holder plate  90  affixed in each end of the support member  62 ; this structure is shown in FIG. 5 of the drawings, and is repeated at each end of the bladder  68 . Thus, as the bladder  68  inflates, the end pins  86  may move freely within the corresponding slots  88  of the retainer plates  90 , while being retained along the side of the I beam support member  62 . A bladder rest or saddle  92 , comprising an elongate, arcuate channel, rests along the web  66  and between the flanges  64  of the I beam support  62  and is sandwiched between the support  62  and bag  68  to provide smooth support for the flexible bladder  68  and to preclude any cutting or chafing of the bladder or bag  68  by the hard edges of the I beam bladder support member  62 . The bladder saddle or rest  92  may be formed of a quarter section of PVC plastic pipe, or other suitable material as desired, so long as the shape and smoothness protects the bladder  68  from damage. 
     A rigid scraper blade  94  is pivotally secured to the support beam  62  by first and second blade attachment plates  96  and  98 , with the first plate  96  being shown in FIG.  5  and the second plate  98  shown in FIG. 6 of the drawings. The two blade attachment plates or lugs  96  and  98  extend from one side of the I beam support  62 , and are spaced apart adjacent opposite ends of the beam  62 , with the scraper blade  94  pivotally secured between the two plates  96  and  98  by an elongate pivot rod  100  which passes through the blade  94  with opposite ends secured in each blade attachment plate  96  and  98 . 
     The scraper blade  94  is preferably formed of a relatively soft, yet durable and rigid non-metallic material, such as urethane plastic as in the blade  20  of the first embodiment conveyor scraper discussed further above, and has a length at least equal to the width of the conveyor belt C. The blade  94  has a first side  102  having a concave bladder pocket  104  formed transversely therein, i.e., parallel to the pivot axis defined by the pivot rod  100 , and an opposite second side  106  with a distal conveyor scraper blade edge  108  extending therefrom, opposite the first side  102 . A pivot fulcrum  110  extends transversely between (i.e., parallel to) the two sides  102  and  106  of the blade  94 , with the pivot rod  100  passing through the pivot fulcrum  110  and the blade  94  pivoting or rocking about the pivot rod  100  and corresponding pivot fulcrum  110  to the limits defined by the support beam  62  on one side, and the conveyor belt C on the opposite side. 
     The inflatable bladder or bag  68  resides within the concave bladder pocket  104  of the pivotally mounted blade structure  94 . When the bladder  68  is inflated, it lifts the first side  102  of the blade  94  away from the rigidly mounted support beam  62 , causing the blade structure  94  to pivot about the pivot rod  100  which passes through the pivot fulcrum  110  of the blade  94  between the two sides  102  and  106  of the blade  94 . This results in the conveyor scraper edge  108  of the blade  94  bearing against the conveyor belt C, to evenly and uniformly scrape away any residue or foreign matter from the surface of the conveyor C. 
     It will be seen that the pressure of the blade edge  108  against the conveyor C is easily adjusted as desired, by adjusting the pressure applied to the inflatable bag or bladder  68  as desired. If less scraping pressure is desired, the pressure to the bladder  68  is reduced, with the bladder  68  being capable of complete deflation if so desired. This is accomplished by means of the operating system comprising the pressure source  52 , pressure regulator  54 , and relief valve  56  which may be used with the first embodiment belt scraper, and shown schematically in FIG. 4 of the drawings. As in the case of the first embodiment scraper, the inflatable bag or bladder  68  of the second embodiment conveyor scraper of FIGS. 5 and 6 may be inflated using any practicable hydraulic or pneumatic fluid, as desired. 
     In summary, the embodiments of the present conveyor belt scraping device each provide a much more positive means of scraping and cleaning residue from the working surface of a conveyor belt, than various devices of the prior art. The present scraper mechanism embodiments provide a consistent scraping pressure across the entire width of the conveyor belt, which prior art machines with their typical scraper support means at each end of the scraper blade or bar, cannot do due to the sag or flex of the bar. The present scraper machine embodiments also reduce wear and tear on the belt, due to the relatively soft plastic material of the scraper blade. Yet, the depth of the blade, along with the uniform and consistent support of the blade by means of the inflatable bladder used in the present scraper mechanism, preclude any bending or sagging of the blade, thereby insuring a uniform scraping action across the entire width of even the widest conveyor belts in use. 
     Accordingly, the present conveyor belt scraper will prove to be of great value in virtually any industry using conveyor belts, and will save considerable time and expense in terms of down time and belt replacement due to its uniform scraping action across the entire width of the belt and the reduction in wear and tear on the belt. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.