When setting up a new belt scraper, or when changing the blades on an existing scraper, the blades on the blade support arms must first be brought into contact with the belt while a connecting clutch is loosened. The final tightening of the bolts re-engaging the clutch must be accomplished while holding the blade arms in an adjusted position. This procedure can be awkward and time-consuming and may require a person to get under the belt and hold the belts in position while a second person tightens the correcting clutch.

The invention is directed to an improved belt scraper apparatus in which first and second pairs of primary or scraper blade support arms carry or support transversely oriented belt scraper blades, and including an improved mechanism by which the angular position of the primary support arras may be adjusted in relation to each other and

in relation to the respective actuator arms. The relative position of one of the actuator arms, at each end of the belt scraper, may be angularly repositioned with respect to its associated shaft and primary arm, by rotating a pinion gear which is in mesh with a larger bull gear. The gears are mounted in a housing forming part of the actuator arm support. The bull gear, in the housing, is in driving relation to the shaft which carries the associated primary arm. A stub shaft extends from the pinion gear external to the housing, providing for the attachment of a wrench or crank to make the required adjustment.

Changes in the relative angular position of the blade support arms and actuator arms provide initial adjustment or blade at opposite sides of the belt, and can readily be accomplished by one person, while viewing the position of the scrapers. Once adjusted, the position may be locked by clamping the gears in adjusted position.

The invention may be described as a belt scraper for removing debris from the outer surface of a conveyor belt, such as a bulk-type conveyor belt, and includes a first pair of blade supporting arms, a transversely oriented belt scraper blade mounted on the first pair of arms adapted to be positioned in running engagement with the outer surface of a conveyor belt. A second pair of blade supporting arms has a second transversely oriented belt scraper blade mounted thereon and adapted to be positioned in running engagement with an outer surface of the belt in spaced relation to the first scraper blade. A shaft is mounted on each of the pairs of arms for independent rotational movement. Tension arms, one for each pair of blade supporting arms, are connected to the associated shaft

for urging the scraper blades into engagement with the belt. The invention as described is an improvement in the apparatus for adjusting the relative angular position of one of the pair of blade supporting arms to its associated tension arm, characterized by a gear housing mounted on the associated tension arm containing a first gear or a bull gear which is in driving relation to the associated shaft, a second gear or a spur gear is in the gear housing in running engagement with the first gear, and has a drive portion which is connected to rotate the second gear thereby changing the relative angular position of the associated blade support arms with respect to the tension arm.

The invention is of a belt scraper further characterized by the fact that the second gear drive portion is accessible at one lateral side of the belt, whereby the associated blade may be adjusted into a desired running engagement with the belt surface while observing the belt surface.

In order that the invention may be more readily understood, reference will now be made to the accompanying drawings, in which:

Fig. 1 is a perspective view of a belt scraper in accordance with this invention;

Fig. 2 is a partially broken away plan view of the scraper of Fig. 1;

Fig. 3 is a sectional view taken generally along the line 3—3 of Fig. 2;

Fig. 4 is an enlarged section taken generally along the line 4—4 of Fig. 2; and

Fig. 5 is an end view, with the cover plate removed, of one of the gear-adjusting mechanisms of this invention.

A belt scraper is shown in Fig. 1 as including a pair of scraper blades for engagement with the outside surface of a belt 12. The spaced apart scraper includes a first or primary belt scraper blade 14 and a second belt scraper blade 16. The blade 14 is mounted on primary support arms 18 and 20, while the blade 16 is carried on arms 22 and 24. The belt scraper of this invention may be positioned to engage the outside surface of the belt 12 at the head roll of the conveyor, or may incorporate and include its own backing roll 25 which supports the belt 12 for movement across the respective belt blades 14 and 16. The scraper blades 14 and 16, and the associated support arms for these blades, are mounted for rotation about a common transverse axis. This mounting arrangement permits the blade 14 to move independently of the blade 16. The mechanism which supports the respective pairs of support arms 18, 20 and 22, 24 is essentially duplicated at each side of the belt scraper and is described in further detail in connection with Figs. 2-4.

Separate actuator or tension arms are associated with each of the blades 14 and 16. One pair of actuator arms 30 are connected to move the blade 14, while the adjacent pair of arms 32 are each connected to move the blade 16. The remote ends of the pairs of arms 30 and 32 are each connected to an air-over-hydraulic automotive type actuator 35 as described in my patent. The belt scraper is symmetrical in that actuator arms 30 and 32, and the associated adjustment mechanisms are positioned at each

lateral side of the belt 12, and each pair of the arms 30 and 32 is biased or controlled by an actuator 35. Air under controlled pressure is applied to each of the actuators from a supply tank 36 and through a regulator 37, as illustrated in Fig. 1.

The primary scraper blade 14 and the secondary scraper blade 16 are mounted for rotation on concentric common axes. Since the rotational mounting and support structure for the blade arms and for the tension or actuator arms are essentially identical, at either side of the belt, the sectional illustration of the mounting of Figs. 3 and 4, are typical for both of the mounting arrangements at either side of the belt.

An outer tubular shaft 50 supports one of the pair of blade arms and is mounted in concentric relation to an inner tubular shaft 52 which supports the other of the pair of blade arms. As shown in Fig. 3, a solid support rod 53 may be extended through the inside of the shaft 52, for the full transverse width of the scraper, for supporting the scraper in its position, in relation to the belt 12.

The blade supporting arms are not shown in Fig. 4, but the adjustable arm-attaching knuckle joints are shown, associated with each of the shafts 50 and 52. A first knuckle joint 55 includes an arm portion 56 welded to the outer surface of the shaft 50 and carrying a rotatably lockable blade arm support member 57. The blade arm support member 57 has a recessed portion 58 for receiving the inner end of one of the blade-supporting arms, such as the arm 18. Also, as shown in Fig. 4, the arm support member 57 and arm portion 56 of the knuckle joint 55 have tapered interfitting parts in the form of a conical support portion 59 on the

blade arm support member 57 received within a suitable tapered opening formed in the arm 56, and retained in an adjusted angular position by a stud bolt 59'. The relatively interfitting parts may be provided with interfitting serrations or knuckles for defining and maintaining an adjusted position of the respective blade support arms with respect to their associated support tubes or shafts 50, 52.

A duplicate arrangement of parts is associated with the inner tubular shaft 52, including a knuckle joint arm portion 55a welded to an extended end of the shaft 52, and a blade support member 57a, identical to the member 57 angularly adjustably mounted on the knuckle joint arm portion 56a. The respective concentric shafts 50 and 52 are free to rotate one relative to the other on a pair of spaced polymeric bushings 60. The spacing between the bushings is maintained by a tubular spacer sleeve 62 extending between the bushings 60. A block support 63 is mounted in concentric relation to the outer shaft 60 on a resilient bushing 64, and forms a support for the pillow block 66 (Fig. 4) for the backing roll 25.

Each of the tension arms are adjustably carried on one of the concentric shafts 50 or 52. One of these adjusting arrangements is a continuous geared adjustment. Such continuous adjustment is only required for one of the two tension arms 30, 32, on either side of the machine, and the other tension arm may be mounted to its associated shaft through a serrated clutch. Such adjustment is commonly made only at one time, such as during initial set-up to create a desired relationship between the position of the tension or

actuator arm and the blade. Thereafter, the final adjustments may be made through the continuous gear adjustment of this invention.

The means for adjusting the relative position of one of the actuator or tension arms, such as the arm 32, to the associated shaft 50 includes a tension arm holder 70. The holder 70 is mounted on a serrated ring 72, by stud bolts 73 and a clamping ring 74. When the nuts 75 on the stud bolts 73 are loosened, the tension arm holder 70 may be rotated with respect to the fixed position of the ring 72, and reclamped by the tightening of the nuts 75.

The invention provides for the continuous adjustment of the other of the actuator arms 30 with respect to its associated shaft 52 from positions alongside of the belt 121 In this manner the associated blade arms 18, 20 and the blade 14 may be moved with respect to the blade 16, to bring the parts into a proper scraper relation as shown in of Fig. 1.

A tension arm holder 80 supports the tension arm 30, as shown in Figs. 4 and 5. The arm holder 80 is in the form of a gear housing which rotatably contains a pair of constantly intermeshed gears for adjusting the relative position of the housing or arm support 80 with respect to the shaft 52. A pinion gear 82 is in constant mesh with a bull gear 83. The gear 83 is fixedly mounted by welding on the end of the shaft 52 so as to be mounted in driving relation to the shaft 52, and may be referred to as a first gear. The pinion gear 83 may be referred to as a second gear and has a bushing 84 received within a suitable opening 85 on the holder 80.

The gears are held in place in the housing 80 by a cover plate 86. A drive portion of shaft 88 of the pinion gear 82 extends through the plate 86 and may be considered as the means connected to rotate the second gear 82. The cover plate 86 is retained on the tension arm holder 80 by a series of stud bolts 90 and hex nuts 92.

In order to make an adjustment, the nuts 92 are loosened, permitting the pinion gear 82 to be rotated by the shaft 88, thereby affecting relative rotation between the holder 80 and the inner shaft 52. The rotation of the second gear by the drive portion changes the relative angular position of the associated blade-support arms with respect to the tension arms. The drive shaft 88 is accessible at one lateral side of the belt, in the duplicate mechanism on either side of the belt scraper. The adjusted positioned is had by tightening the nuts 92 against the cover plate 86.

In the operation of the invention, the upstream and downstream scraper blades 14 and 16 respectively are biased into running engagement with an outer surface of the belt 12 by the air cylinder 35 acting through the tension arms 30 and 32. It is important, in view of the limited travel of the air cylinders 35, to provide for a positioning of the blades in relation to the belt surface, at initial installation of the scraper and following replacement of the blades. The angle of the blades with respect to the surface of the belt may be adjusted by suitable adjustment at the connecting knuckle parts 56, 57 and 56a, 57a, as previously described. Generally, once this setting has been established, no further adjustment is required. Similarly, the angle of the tension arm 32 or its relative position on

the actuator shaft 50 may be adjusted, by selecting the position of the tension arm holder 70 with respect to the serrated disc 72, and then tightening the nuts 75 to maintain this position. Again, this is an adjustment which, once made, is generally not repeated for a given installation.

The scraper supporting arms, for maintenance and scraper blade replacement, may be swung apart conveniently by loosening the clamping action of the nuts 72 and simply rotating the spur gear 82 through the shaft 80 from the positions alongside the belt. Similarly, an adjusted position may be readily and easily obtained by reversing this procedure, and therefore maintained by clamping the cover plate 86 against the meshed gears 82, 83. This adjustment is made at each of the adjusting mechanisms at each side of the belt scraper to achieve the desired contact and uniformity of pressure across the transverse length of the blades.

What is claimed is: