WO2009114450A1

WO2009114450A1 - Biasing device for bulk material transfer devices and method of using the same

Info

Publication number: WO2009114450A1
Application number: PCT/US2009/036476
Authority: WO
Inventors: David William Mueller; George Allen Twidell; David Martin Tomsic; Timothy Michael Mandrell; Louis Allen Demay
Original assignee: Martin Engineering Company
Priority date: 2008-03-10
Filing date: 2009-03-09
Publication date: 2009-09-17

Abstract

An assembly comprises a bulk material vibratory device and a biasing device. The bulk material vibratory device comprises a frame, a screen, and a shaft. Pivotal motion of the shaft creates tension in the screen. The biasing device comprises a first and second portions and a link. The first portion is fixed to the frame. The second portion is attached to the shaft. The link comprises a rod and spring. The rod is threadably connected to the first portion of the biasing device, and is slideably connected to the second portion of the biasing device. The spring is biased against the second portion of the biasing device in a manner creating torque between the first and second portions of the biasing device. The torque generates tension in the screen and is adjustable by moving the link relative to the first portion of the biasing device via the threads.

Description

BIASING DEVICE FOR BULK MATERIAL TRANSFER DEVICES AND METHOD OF USING THE SAME

Cross-Reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Application No. 61/035,291 filed March 10, 2008 and U.S. Application No. 12/400,107 filed March 9, 2009.

Statement Regarding Federally Sponsored Research or Development

[0002] Not Applicable.

Appendix

[0003] Not Applicable.

BACKGROUND OF THE INVENTION

Field of the Invention

[0004] This invention relates generally to bulk material transfer devices. More particularly, this invention pertains to a biasing device for providing a biasing torque or linear force for use in tensioning vibratory screens of bulk material vibratory devices and for biasing conveyor belt scrapers against conveyor belts.

General Background Technology

[0005] Various bulk material transfer systems utilize some means of biasing particular components of such systems. For example, bulk material vibratory devices, of the type used for sorting the size of various bulk materials, typically comprise one or more cloth screens that that must be held in tension to effectively operate. One way to tension such screen cloths is to utilize come-a-longs acting on moment arms to bias shafts that support the opposite end

4899914.1 1 of such cloths. However, the use of come-a-longs makes it difficult to precisely control and adjust the amount of tension applied to a screen cloth. Additionally, harmonic vibrations at or near the natural frequency of the come-a-longs can cause the tension applied to such screens to vary or even cease. Other bulk material transfer devices, such as conveyors, often comprises scraper blades that are torsionally or linearly biased against the conveyor belt of such devices via springs acting on moment arms. Typically, such torsional biasing devices are locked in a particular setting via a pair of threaded nuts that are biased against each other. These devices too are subject to loosening when subjected to vibrations. Additionally, adjustment of such devices often requires the simultaneous use of at least two wrenches.

SUMMARY OF THE INVENTION

[0006] The present invention overcome some of the disadvantages prior art torsional tensioning devices used in bulk material handling devices.

[0007] In a first aspect of the invention, an assembly comprises a bulk material vibratory device and a torsional biasing device. The bulk material vibratory device comprises a frame, a screen, and a shaft. The shaft has a longitudinal axis and is connected to the screen in a manner such that pivotal motion of the shaft about the longitudinal axis relative to the frame is able to create tension in the screen. The torsional biasing device comprises a first portion, a second portion, and a link. The first portion is fixed to the frame. The second portion is attached to the shaft in a manner such that second portion pivots with the shaft about the longitudinal axis relative to the frame. The link comprises a rod portion and spring. The rod portion has a link axis and threads that spiral about the link axis. The threads threadably connect the rod portion to the first portion of the torsional biasing device. The rod portion is

4899914.1 2 slideably connected to the second portion of the torsional biasing device along the link axis. The spring is biased against the second portion of the torsional biasing device in a first direction along the link axis in a manner creating torque between the first and second portions of the torsional biasing device. The torque generates tension in the screen of the bulk material vibratory device and is adjustable by moving the link relative to the first portion of the torsional biasing device via the threads.

[0008] Another aspect of the invention pertains to a method of adjusting a bulk material vibratory device. The bulk material vibratory device comprises a frame, a screen, a shaft, and a torsional biasing device. The shaft has a longitudinal axis and is connected to the screen in a manner such that pivotal motion of the shaft about the longitudinal axis relative to the frame creates tension in the screen. The torsional biasing device comprises a first portion, a second portion, and a link. The first portion is fixed to the frame. The second portion is attached to the shaft in a manner such that second portion pivots with the shaft about the longitudinal axis relative to the frame. The link comprises a rod portion and a spring. The rod portion has a link axis and threads that spiral about the link axis. The threads threadably connect the rod portion to the first portion of the torsional biasing device. The rod portion is slideably connected to the second portion of the torsional biasing device along the link axis. The method comprises a step of revolving the rod portion of the link about the link axis in a manner that translates the rod portion relative to the first portion of the torsional biasing device via the threads of the rod portion. The translation of the rod portion relative to the first portion of the torsional biasing device causes the spring to bias the second portion of the torsional biasing device in a first direction along the link axis with an increasing force. The increasing force causes an increasing torque between the first and second portions of the

4899914.1 3 torsional biasing device. The increasing torque results in an increasing tension in the screen of the bulk material vibratory device.

[0009] In yet another aspect of the invention, an assembly comprises a bulk material conveyor device and a torsional biasing device. The bulk material conveyor device comprises a frame, a conveyor belt, a shaft, and at least one conveyor belt scraper. The shaft has a longitudinal axis and is connected to the scraper in a manner such that pivotal motion of the shaft about the longitudinal axis relative to the frame is able to force the scraper against the conveyor belt. The torsional biasing device comprises a first portion, a second portion, and a link. The first portion is fixed to the frame. The second portion is attached to the shaft in a manner such that second portion pivots with the shaft about the longitudinal axis relative to the frame. The link comprises a rod portion and spring. The rod portion has a link axis and threads that spiral about the link axis. The threads threadably connecting the rod portion to the first portion of the torsional biasing device. The rod portion is slideably connected to the second portion of the torsional biasing device along the link axis. The spring is biased against the second portion of the torsional biasing device in a first direction along the link axis in a manner creating torque between the first and second portions of the torsional biasing device. The torque biases the scraper against the conveyor belt. The torque is also adjustable by moving the link relative to the first portion of the torsional biasing device via the threads. [0010] Still further, another of the aspect of the invention pertains to a method of adjusting a bulk material conveyor device. The bulk material conveyor device comprises a frame, a conveyor belt, a shaft, and at least one conveyor belt scraper. The shaft has a longitudinal axis and is connected to the scraper in a manner such that pivotal motion of the shaft about the longitudinal axis relative to the frame is able to force the scraper against the conveyor

4899914.1 4 belt. The torsional biasing device comprises a first portion, a second portion, and a link. The first portion is fixed to the frame. The second portion is attached to the shaft in a manner such that second portion pivots with the shaft about the longitudinal axis relative to the frame. The link comprises a rod portion and a spring. The rod portion has a link axis and threads that spiral about the link axis. The threads threadably connect the rod portion to the first portion of the torsional biasing device. The rod portion is slideably connected to the second portion of the torsional biasing device along the link axis. The method comprises a step of revolving the rod portion of the link about the link axis in a manner that translates the rod portion relative to the first portion of the torsional biasing device via the threads of the rod portion. The translation of the rod portion relative to the first portion of the torsional biasing device causes the spring to bias the second portion of the torsional biasing device in a first direction along the link axis with an increasing force. The increasing force causing an increasing torque between the first and second portions of the torsional biasing device. The increasing torque results in an increasing contact force between the scraper and the conveyor belt.

[0011] In yet another aspect of the invention, an assembly comprises a bulk material conveyor device and a biasing device. The bulk material conveyor device comprises a conveyor belt and at least one conveyor belt scraper. The biasing device comprises a first portion, a second portion, and a link. The link comprises a rod portion and spring. At least one of the first and second portions is fixed relative to the frame. The rod portion has a link axis and threads that spiral about the link axis. The threads threadably connect the rod portion to the first portion of the torsional biasing device. The rod portion is slideably connected to the second portion of the torsional biasing device along the link axis. The

4899914.1 5 spring is biased against the second portion of the biasing device in a first direction along the link axis in a manner creating a force between the first and second portions of the biasing device. The force biases the scraper against the conveyor belt. The force is also adjustable by moving the link relative to the first portion of the torsional biasing device via the threads. [0012] Further features and advantages of the present invention, as well as the operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a perspective view of a bulk material vibratory device comprising a biasing device in accordance with the invention.

[0014] Figure 2 is a perspective view of the biasing device of the a bulk material vibratory device shown in Figure 1.

[0015] Figure 3 is another perspective view of the biasing device shown in Figure 2.

[0016] Figure 4 is side view of the biasing device shown in Figures 2 and 3.

[0017] Figure 5 is a top view of the biasing device shown in Figures 2-4.

[0018] Figure 6 is a cross-section view of the biasing device shown in Figures 2-5 and is taken about the line 6-6 shown in Figure 5.

[0019] Figure 7 is another perspective view of the biasing device shown in Figures 2-6 and shown with a few components removed for purposes of describing the invention.

[0020] Figure 8 is a close-up perspective view of the boss of the locking portion of the biasing device shown in Figures 2-7.

4899914.1 [0021] Figure 9 is perspective view of the locking pin of the biasing device shown in Figures

2-8.

[0022] Figure 10 is a close-up perspective view of the biasing device cross-sectioned as shown in Figure 6.

[0023] Figure 11 is a cross-section view of the biasing device shown in Figures 2-10 and is taken about the line 11-11 shown in Figure 4.

[0024] Figure 12 is a perspective view of a bulk material conveyor device comprising a scraper blade biasing device in accordance with the invention.

[0025] Figure 13 is a perspective view of a biasing device in accordance with the invention for use as a tensioner for conveyor belt scraper blades.

[0026] Reference numerals in the written specification and in the drawing figures indicate corresponding items.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] A torsional biasing device 10 in accordance with the invention adapted for use in connection with bulk material vibratory devices is shown in Figures 1-11. A typical vibratory device 12 comprises one or more tensioned cloth screens 14 mounted to a frame 16.

The screen 14 is attached to at least one shaft 18 that is pivotally connected to the frame 16 about its longitudinal axis. Tension is applied to the screen 14 by torsionally biasing the shaft

18 relative to the frame 16 via the torsional biasing device 10.

[0028] The torsional biasing device 10 comprises a first portion 20 that is configured to be mounted to the frame 16 of vibratory device 12. A second portion 22 of the torsional biasing device 10 is attached to the shaft 18 of the vibratory device 12 in a manner such that it pivots

4899914.1 7 about the longitudinal axis of the shaft 18 together with the shaft. The torsional biasing device 10 further comprises a link 24. The link 24 operative connects the first portion 20 of the torsional biasing device 10 to its second portion 22 in a manner creating a torque between the first and second portions that acts about the longitudinal axis of the shaft 18. [0029] The first portion of the torsional biasing device 10 preferably comprises a mounting plate 26, an extension bracket 28, and a threaded sleeve 30. Preferably, each is formed of steel. The mounting plate 26 is preferably square plate material having a centrally positioned shaft opening 32 and a plurality of countersunk mounting holes 34 spaced about the shaft opening. The mounting holes 34 are configured to allow the mounting plate 26 to be rigidly secured to the frame 16 of the vibratory device 12 via a plurality of machine screws (not screws). The extension bracket 28 extends from the mounting plate 26 radially outward relative to the shaft opening 32. The threaded sleeve 30 preferably has ACME female threads and is preferably pivotally attached to the extension bracket 28 about an axis that is parallel to the axis of shaft 18. The extension bracket 28 is preferably bolted to the mounting plate 26. The threaded sleeve 30 preferably has a grease fitting or opening for lubricating the threads. [0030] The second portion 22 of the torsional biasing device 10 preferably comprises a collet 34, a moment arm lever 36, and a guide sleeve 38. The collet 34 is configured and adapted to encircle the shaft 18 of the vibratory device 12 and is configured to be rotationally fixed to the shaft via a plurality of set screws 40. The moment arm lever 36 extends radially outward from the collet 34. The guide sleeve 38 is preferably pivotally connected to the moment arm lever 36 about an axis that is parallel to the longitudinal axis of the shaft 18, and is preferably generally cylindrical. The guide sleeve 38 also preferably comprises a planar bearing surface 42, which is preferably annular, and a locking portion 44.

4899914.1 8 [0031] The locking portion 44 preferably comprises a boss 46, a coil compression spring 48, a locking pin 50, a cap 52, a spring pin 54. The boss 46 is preferably welded to the main cylindrical portion of the of the guide sleeve 38, and preferably has a through-hole 56 that extends at a right angle to the axis of the main cylindrical portion. The through-hole 56 has a relatively large diameter adjacent the main cylindrical portion of the guide sleeve 38, and transitions to a smaller diameter adjacent the terminal end 60 of the boss 46, forming a step 62 therebetween. A slot 64 is preferably formed into the terminal end of the boss and extends through the boss perpendicular to the through-hole 56. The locking pin 50 preferably has a large diameter portion 66 and a small diameter portion 68. The small diameter portion 68 of the locking pin 50 is dimensioned similar to the dimension of the smaller diameter of the through-hole 56 of the boss 46. Likewise, the large diameter portion 66 of the locking pin 50 is dimensioned similar to the dimension of the larger diameter of the through hole 56 of the boss 46. A pin hole 70 extends through the small diameter portion 68 of the locking pin 50, perpendicular to the length of the locking pin. The end of the large diameter portion 66 of the locking pin 50 preferably terminates in a manner forming a wedge having a cam surface 72 and a locking surface 74.

[0032] The cap 52 of the locking portion 44 comprises a hollow cylindrical body portion 76 and a discoidal end portion 78. A pin hole 80 extends through the cylindrical body portion 76 and a locking pin opening 82 extends through the discoidal portion 78. The discoidal portion 78 of the cap 52 has a slightly lager diameter than does the cylindrical body portion 76, thereby making the cap 52 easy to grip.

[0033] As assembled, the locking pin 50 of the locking portion 44 is slideably received in the boss 46 along with the compression spring 48, which encircles the small diameter portion 68

4899914.1 9 of the locking pin and becomes sandwiched between the step 62 of the boss and the large diameter portion 66 of the locking pin. The cap 52 is position over the terminal end 60 of the boss 46, with the small diameter portion 68 of the locking pin 50 extending through the locking pin opening 82 of the cap. The pin hole 70 of the locking pin 50 and pin hole 80 of the cap 52 are aligned and the spring pin 54 in press-fit thereinto. Thus, as assembled, the compression spring 48 of the locking portion 44 biases or urges the locking pin 50 toward the axis of the main cylindrical portion of the guide sleeve 38 to a point where the spring pin 54 of the locking portion bottoms out in the slot 64 of the boss 46. This position is hereinafter referred to as the "locking position" of the locking portion 44. The locking pin 50 can be moved away from the center axis of the main cylindrical portion of the guide sleeve 38 by pulling on the cap 52 with a force sufficient to overcome the urging of the compression spring 48. The locking pin 50 can be temporarily secured in this "unlocking position" by turning the cap 52 in a manner such that the spring pin 54 is no longer aligned with the slot 64 of the boss 46, and is therefore held against the outer surface of the terminal end 60 of the boss.

[0034] The link 24 of the torsional biasing device 10 preferably comprises a rod portion 84, a compression spring 86, a spring retainer cap 88, a spring retainer washer 90, a wrench fitting 92, and a back-off portion 94. The rod portion 84 preferably comprises male ACME threads 96 that extend at least partially along the length of the rod portion 84 and that are dimension to intermesh with the female threads of the threaded sleeve 30 of the first portion 20 of the torsional biasing device 10. The wrench fitting 92 is preferably a hex-shaped protrusion and is preferably adjacent one end of the rod portion 84. The back-off portion 94 of the link 24 preferably comprises a annular ring protrusion fixed to and encircling the rod portion 84

4899914.1 10 nearer the rod portion's longitudinal center. The spring retainer cap 88 is preferably secured to the rod portion 84 near the end adjacent the wrench fitting 92. The compression spring 86 encircles the rod portion 84 and is preferably sandwiched by and between the spring retainer cap 88 and the spring retainer washer 90. The rod portion 84 preferably comprises an elongate channel or slot 98 extending parallel to the longitudinal axis of the rod portion. [0035] As assembled for use, the threads 96 of the rod portion 84 of the link 24 are threadably engaged with the threads of the threaded sleeve 30 of the first portion 20 of the torsional biasing device 10. The guide sleeve 38 of the second portion 22 of the torsional biasing device 10 encircles the rod portion 84 of the link 24 and is position between the spring retainer washer 90 and the back-off portion 94 of the link 24. The mounting plate 26 of the first portion of the torsional biasing device 10 is fastened to the frame 16 of the vibratory device 12. Additionally, the collet 34 of second portion 22 of the torsional biasing device 10 is secured to the shaft 18 of the vibratory device 12 via the set screws 40. [0036] When used to initially apply tension the screen 14 of the vibratory device 12, tension in the screen is increased by using a wrench to rotate the rod portion 84 of the link 24 in a manner drawing the wrench fitting 92 end of the rod portion toward the threaded sleeve 30 of the first portion 20 of the torsional biasing device. When this occurs, the spring retainer cap 88 of the link 24 moves an equal amount toward the threaded sleeve 30 of the first portion 20 of the torsional biasing device 10. This causes the spring retainer cap 88 to move the compression spring 86 toward the guide sleeve 38 of the second portion 22 of the torsional biasing device 10. Eventually, the compression spring 86 and the spring retainer washer 90 become sandwiched between the bearing surface 42 of the guide sleeve 38 and the spring retainer cap 88. Further rotation of the rod portion 84 thereafter causes the compression force

4899914.1 1 1 within the compression spring 86 to act upon the guide sleeve 38 of the second portion 22 in a direction along the link axis toward the first portion 20. This force on the second portion 22 of the torsional biasing device 10 creates a torque between the first 20 and second portions of the device, which is transmitted to the shaft 18 of the vibratory device 12 in a manner tensioning the screen 14. Continuing to rotate the rod portion of the link 24 will cause the compression force within the compression spring 86 to increase, thereby increasing the tension in the screen 14.

[0037] The above mentioned tensing can occur with locking portion 44 of the torsional biasing device 10 in its locking position or its unlocking position. When the locking portion 44 is in its unlocking position, the rod portion 84 of the link 24 can be turned in either direction without being obstructed by the locking portion. When the locking portion 44 is in its locking position, the cam surface 72 and the locking surface 74 of the locking pin 50 are biased toward the longitudinal link axis of the rod portion 84. Thus, when the elongate channel 98 the locking pin 50 are aligned, the cam surface 72 and the locking surface 74 of the locking portion move into the elongate channel. Notably however, the cam surface 72 of the locking pin 50 is configured to force the locking pin back out of the elongate channel 98 (overcoming the biasing of the compression spring 48 of the locking portion 44), when the rod portion 84 is rotated in the direction for increasing tension. When the rod portion 84 attempts to rotate the opposite direction with the locking pin 50 in its locking position, the locking surface 74 of the locking pin will bear against a side face of the elongate channel 98 in a manner preventing such rotation. Thus the locking pin 50 of the locking portion 44 acts like a ratchet.

4899914.1 12 [0038] In view of the foregoing, it should be appreciated that to release or decrease tension in the screen 14 of the vibratory device 12, the locking portion 44 must be placed in its unlocking position, or alternatively, the locking pin 50 can be rotated 180 degrees to thereby ratchet in the opposite direction. After doing so, the rod portion 84 of the link 24 can be rotated in a direction causing the wrench fitting 92 end of the rod portion to move away from the threaded sleeve 30 of the first portion 20 of the torsional biasing device 10. It should be appreciate that this reverses the steps described above and thereby decreases the tension in the screen 14, ultimately to zero. Further rotation of the rod portion 84 in this reverse direction ultimately causes the back-off portion 94 of the link 24 to engage against the guide sleeve 38 of the second portion 22 of the torsional biasing device 10. This pushes the guide sleeve 38 of the second portion 22 away from the threaded sleeve 30 of the first portion 20 of the torsional biasing device 10. This rotates the shaft 18 of the vibratory device 12 in a direction that creates slack in the screen 14 of the vibratory device. Such slack in the screen 14 facilitates servicing or replacement of the screen.

[0039] As mentioned above, in addition to tensioning vibratory devices, the invention is applicable to torsionally tensioning conveyor belt scrapers against conveyor belts. The above-described embodiment of a torsional biasing device could be used for such purpose. However, it should be appreciated that, in general, conveyor belt scraper devices require a comparatively smaller range of angular motion. As such, in accordance with the invention, an alternative torsional biasing device adapted for conveyor devices can be particularly adapted for such use. Figures 12 and 13 depict a second embodiment of a torsional biasing device 10' in accordance with the invention that is adapted and configured for use in connection with torsionally biasing conveyor belt scrapers against conveyor belts. In general,

4899914.1 13 the torsional biasing device 10' is substantial similar to the torsional biasing device 10 adapted for tensioning a screen of a vibratory device. As such, similar components are described and labeled in the drawing figures with similar reference numerals followed by an apostrophe. This being said, the following description is directed primarily only to the differences between the embodiments and it should be appreciated that, except for such differences, the above-description also generally applies to this second embodiment. [0040] The torsional biasing device of the second embodiment is shown in Figure 12 attached to a conveyor belt device 12'. The conveyor belt device 12' comprises scraper blades 14' mounted to a shaft 18' that is pivotally connect to a frame 16'. In operation, the scraper blades 14' are forced against the conveyor belt of the conveyo.r belt device 12' by applying a torque to the shaft 18' relative to the frame 16'. Periodically, the scraper blades 14' must be replaced or otherwise serviced, during which time the torsion must be released and the shaft 18' rotated. However, as mentioned above, this generally requires less angular rotation of the shaft 18' than is required to change the screen of a vibratory device. Thus, the rod portion 84' of the link 24' of the torsional biasing device 10' can be relatively shorter. Additionally, less of a range of rotation between the link 24' and the second portion 22' of the torsional biasing device 10' occurs. As such, the second portion 22' of the torsional biasing device 10' can comprise a simple opening 38' through the moment arm lever 36' of the second portion 22' in place of a pivotally attached guide member. The locking portion 44' can be rigidly fixed to the moment arm lever 36' of the second portion 22' or alternatively to the threaded sleeve 30' of the first portion 20' of the torsional biasing device 10' (the former is shown in the drawing figures).

4899914.1 14 [0041] In accordance with the invention, the above-described embodiments of the invention can to modified to form other embodiments of the invention. For example, the rod portion of a link could be threaded its entire length and the locking portion could comprises a simple threaded bolt or set-screw that is threadably moveable into and out of the elongate channel of the rod portion. Additionally, the wrench fitting of the link could be simply a nut welded to the rod portion or simply a pair of opposite facing parallel flat surfaces machined into the rod portion. Various other modifications should be appreciated by those skilled in the relevant art.

[0042] It should also be appreciated that aspects of the invention can also be used in connection with linearly biasing components of bulk material devices. For example, although a conveyor scraper blade is often torsionally biased against a conveyor belt, a scrapper blade can also be linearly biased against a conveyor belt. It should be appreciated that the torsional biasing devices described above generate biasing torque by transforming linear biasing force into biasing torque. If desired, the link element of the above-described embodiments could be mounted to any two components in place of the first and second portions of the above- described embodiments, thereby creating a biasing tension or biasing compression between such components. The locking portion could also be attached to either of such components to thereby prevent or limit the rotation of the rod portion of the link. One component could be part of the frame of a bulk material conveyor and the other could be a support member upon which a scraper blade is mounted. It should also be appreciate that, if desired, a plurality of such biasing devices could be attached to such a support member in a manner such that the biasing devices provide the sole means of supporting the support member.

4899914.1 15 [0043] As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.

[0044] It should also be understood that when introducing elements of the present invention in the claims or in the above description of the preferred embodiment of the invention, the terms "comprising," "including," and "having" are intended to be open-ended and mean that there may be additional elements other than the listed elements. Additionally, the term "portion" should be construed as meaning some or all of the item or element that it qualifies. Moreover, use of identifiers such as first, second, and third should not be construed in a manner imposing any relative position or time sequence between limitations. Still further, the order in which the steps of any method claim that follows are presented should not be construed in a manner limiting the order in which such steps must be performed.

4899914.1 16

Claims

What is Claimed Is:

1. An assembly comprising: a bulk material vibratory device, the bulk material vibratory device comprising a frame, a screen, and a shaft, the shaft having a longitudinal axis and being connected to the screen in a manner such that pivotal motion of the shaft about the longitudinal axis relative to the frame is able to create tension in the screen; a torsional biasing device, the torsional biasing device comprising a first portion and a second portion, the first portion being fixed to the frame, the second portion being attached to the shaft in a manner such that second portion pivots with the shaft about the longitudinal axis relative to the frame, the torsional biasing device also comprising a link, the link comprising a rod portion and spring, the rod portion having a link axis and threads that spiral about the link axis, the threads threadably connecting the rod portion to the first portion of the torsional biasing device, the rod portion being slideably connected to the second portion of the torsional biasing device along the link axis, the spring being biased against the second portion of the torsional biasing device in a first direction along the link axis in a manner creating torque between the first and second portions of the torsional biasing device, the torque generating tension in the screen of the bulk material vibratory device, the torque being adjustable by moving the link relative to the first portion of the torsional biasing device via the threads.

2. An assembly in accordance with claim 1 wherein the rod portion of the link comprises a channel formed thereinto that extends along the link axis and the torsional biasing device further comprises a locking portion, the locking portion being selectively movable at least

4899914.1 17 partially into and out of the channel, the locking portion preventing the rod portion of the link from revolving in at least one direction about the link axis relative to the first portion of the torsional biasing device when the part of the locking portion is at least partially positioned in the channel, the rod portion being unobstructed from revolving about the link axis relative to the first portion of the torsional biasing device by the locking portion when the part of the locking portion is positioned out of the channel.

3. An assembly in accordance with claim 2 wherein the spring is a first spring and the torsional biasing device comprises a second spring, and the second spring biases the locking portion at least partial into the channel.

4. An assembly in accordance with claim 2 wherein the locking member is fixed to the second portion of the torsional biasing device and pivotally moves therewith about the longitudinal axis of the shaft.

5. An assembly in accordance with claim 1 wherein the first portion of the torsional biasing device comprises a threaded portion that is pivotally connected to the remainder of the first portion about a first pivot axis that is generally parallel to the longitudinal axis of the shaft, the threaded portion being threadably engaged with the threads of the rod portion.

6. An assembly in accordance with claim 5 wherein the second portion of the torsional biasing device comprises a sleeve that is pivotally connected to the remainder of the second portion about a second pivot axis that is generally parallel to the longitudinal axis of the shaft,

4899914.1 18 the sleeve connecting the link to the remainder of the second portion.

7. An assembly in accordance with claim 1 wherein the first direction is toward the first portion of the torsional biasing device.

8. An assembly in accordance with claim 1 wherein the rod portion further comprises a back-off portion, the back-off portion being adapted and configured to engage the second portion of the torsional biasing member in a manner creating an opposite torque between the first and second portions of the torsional biasing device in a manner creating slack in the screen.

9. A method of adjusting a bulk material vibratory device, the bulk material vibratory device comprising a frame, a screen, a shaft, and a torsional biasing device, the shaft having a longitudinal axis and being connected to the screen in a manner such that pivotal motion of the shaft about the longitudinal axis relative to the frame creates tension in the screen, the torsional biasing device comprising a first portion and a second portion, the first portion being fixed to the frame, the second portion being attached to the shaft in a manner such that second portion pivots with the shaft about the longitudinal axis relative to the frame, the torsional biasing device also comprising a link, the link comprising a rod portion and a spring, the rod portion having a link axis and threads that spiral about the link axis, the threads threadably connecting the rod portion to the first portion of the torsional biasing device, the rod portion being slideably connected to the second portion of the torsional biasing device along the link axis, the method comprising:

4899914.1 19 revolving the rod portion of the link about the link axis in a manner that translates the rod portion relative to the first portion of the torsional biasing device via the threads of the rod portion, the translation of the rod portion relative to the first portion of the torsional biasing device causing the spring to bias the second portion of the torsional biasing device in a first direction along the link axis with an increasing force, the increasing force causing an increasing torque between the first and second portions of the torsional biasing device, the increasing torque resulting in an increasing tension in the screen of the bulk material vibratory device.

10. A method in accordance with claim 9 wherein the rod portion comprises a channel that extends along the link axis and the bulk material vibratory device comprises a locking portion, and wherein the method further comprises at least partially positioning the locking portion within the channel of the rod portion in a manner preventing the rod portion from revolving in an opposite direction.

11. A method in accordance with claim 9 further comprising revolving the rod portion in an opposite direction in a manner causing a torque in an opposite direction between the first and second portions of the torsional biasing device.

12. An assembly comprising: a bulk material conveyor device, the bulk material conveyor device comprising a frame, a conveyor belt, a shaft, and at least one conveyor belt scraper, the shaft having a longitudinal axis and being connected to the scraper in a manner such that pivotal motion of

4899914.1 20 the shaft about the longitudinal axis relative to the frame is able to force the scraper against the conveyor belt; a torsional biasing device, the torsional biasing device comprising a first portion and a second portion, the first portion being fixed to the frame, the second portion being attached to the shaft in a manner such that second portion pivots with the shaft about the longitudinal axis relative to the frame, the torsional biasing device also comprising a link, the link comprising a rod portion and spring, the rod portion having a link axis and threads that spiral about the link axis, the threads threadably connecting the rod portion to the first portion of the torsional biasing device, the rod portion being slideably connected to the second portion of the torsional biasing device along the link axis, the spring being biased against the second portion of the torsional biasing device in a first direction along the link axis in a manner creating torque between the first and second portions of the torsional biasing device, the torque biasing the scraper against the conveyor belt, the torque being adjustable by moving the link relative to the first portion of the torsional biasing device via the threads.

13. An assembly in accordance with claim 12 wherein the rod portion of the link comprises a channel formed thereinto that extends along the link axis and the torsional biasing device further comprises a locking portion, the locking portion being selectively movable at least partially into and out of the channel, the locking portion preventing the rod portion of the link from revolving in at least one direction about the link axis relative to the first portion of the torsional biasing device when the part of the locking portion is at least partially positioned in the channel, the rod portion being unobstructed from revolving about

4899914.1 21 the link axis relative to the first portion of the torsional biasing device by the locking portion when the part of the locking portion is positioned out of the channel.

14. An assembly in accordance with claim 13 wherein the spring is a first spring and the torsional biasing device comprises a second spring, and the second spring biases the locking portion at least partial into the channel.

15. An assembly in accordance with claim 13 wherein the locking member is fixed to the second portion of the torsional biasing device and pivotally moves therewith about the longitudinal axis of the shaft.

16. An assembly in accordance with claim 12 wherein the first portion of the torsional biasing device comprises a threaded portion that is pivotally connected to the remainder of the first portion about a first pivot axis that is generally parallel to the longitudinal axis of the shaft, the threaded portion being threadably engaged with the threads of the rod portion.

17. An assembly in accordance with claim 16 wherein the second portion of the torsional biasing device comprises a sleeve that is pivotally connected to the remainder of the second portion about a second pivot axis that is generally parallel to the longitudinal axis of the shaft, the sleeve connecting the link to the remainder of the second portion.

18. An assembly in accordance with claim 12 wherein the first direction is toward the first portion of the torsional biasing device.

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19. An assembly in accordance with claim 12 wherein the rod portion further comprises a back-off portion, the back-off portion being adapted and configured to engage the second portion of the torsional biasing member in a manner creating an opposite torque between the first and second portions of the torsional biasing device in a manner separating the blade from the conveyor belt.

20. A method of adjusting a bulk material conveyor device, the bulk material conveyor device comprising a frame, a conveyor belt, a shaft, and at least one conveyor belt scraper, the shaft having a longitudinal axis and being connected to the scraper in a manner such that pivotal motion of the shaft about the longitudinal axis relative to the frame is able to force the scraper against the conveyor belt, the torsional biasing device comprising a first portion and a second portion, the first portion being fixed to the frame, the second portion being attached to the shaft in a manner such that second portion pivots with the shaft about the longitudinal axis relative to the frame, the torsional biasing device also comprising a link, the link comprising a rod portion and a spring, the rod portion having a link axis and threads that spiral about the link axis, the threads threadably connecting the rod portion to the first portion of the torsional biasing device, the rod portion being slideably connected to the second portion of the torsional biasing device along the link axis, the method comprising: revolving the rod portion of the link about the link axis in a manner that translates the rod portion relative to the first portion of the torsional biasing device via the threads of the rod portion, the translation of the rod portion relative to the first portion of the torsional biasing device causing the spring to bias the second portion of the torsional biasing device in

4899914.1 23 a first direction along the link axis with an increasing force, the increasing force causing an increasing torque between the first and second portions of the torsional biasing device, the increasing torque resulting in an increasing contact force between the scraper and the conveyor belt.

21. A method in accordance with claim 20 wherein the rod portion comprises a channel that extends along the link axis and the bulk material vibratory device comprises a locking portion, and wherein the method further comprises at least partially positioning the locking portion within the channel of the rod portion in a manner preventing the rod portion from revolving in an opposite direction.

22. A method in accordance with claim 20 further comprising revolving the rod portion in an opposite direction in a manner causing a torque in an opposite direction between the first and second portions of the torsional biasing device.

23. An assembly comprising: a bulk material conveyor device, the bulk material conveyor device comprising a conveyor belt and at least one conveyor belt scraper; a biasing device, the biasing device comprising a first portion and a second portion, the biasing device also comprising a link, the link comprising a rod portion and spring, at least one of the first and second portions is fixed relative to the frame, the rod portion having a link axis and threads that spiral about the link axis, the threads threadably connecting the rod portion to the first portion of the torsional biasing device, the rod portion being slideably

4899914.1 24 connected to the second portion of the torsional biasing device along the link axis, the spring being biased against the second portion of the biasing device in a first direction along the link axis in a manner creating a force between the first and second portions of the biasing device, the force biasing the scraper against the conveyor belt, the force being adjustable by moving the link relative to the first portion of the torsional biasing device via the threads.

24. An assembly in accordance with claim 23 wherein the rod portion of the link comprises a channel formed thereinto that extends along the link axis and the biasing device further comprises a locking portion, the locking portion being selectively movable at least partially into and out of the channel, the locking portion preventing the rod portion of the link from revolving in at least one direction about the link axis relative to the first portion of the torsional biasing device when the part of the locking portion is at least partially positioned in the channel, the rod portion being unobstructed from revolving about the link axis relative to the first portion of the torsional biasing device by the locking portion when the part of the locking portion is positioned out of the channel.

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