MXPA98006242A - Self-indicating tensioner for a belt scraper - Google Patents

Abstract

A self-indicating tensioning device (12) for adjusting the contacting force of a scraper blade (17) against the surface of an endless conveyor belt (10) is disclosed. The self-indicating tensioning device (12) includes a flat spring (30) coupled at one end to a rotatable shaft (24), which supports the scraper blade (17), and coupled at the other end of an adjusting mechanism (16). The adjusting mechanism is operable to exert a force on the flat spring (30) which in turn applies a torque to the rotatable shaft (24) for displacing the scraper blade (17). An indicator rod (32) has one end fixed to the rotatable shaft (24) for displacing the scraper blade (17), and the other end is free. A graduated indicator plate (36) is attached to the movable end of the flat spring (30). When the flat spring (30) is deflected in response to the application of force thereto, the displacement of the graduated indicator plate (36) relative to the free end of the indicator rod (32) provides an indication of the amount of force exerted on the flat spring (30), the amount of torque applied to the rotatable shaft (24), or the amount of force with which the scraper blade (17) contacts the conveyor belt (10).

Description

SELF INDICATOR FOR A BAND SCRAPER FIELD OF THE INVENTION The present invention relates to a tension device for adjusting the force with which the blade of a conveyor belt scraper makes contact with the surface of the conveyor belt and, in particular, with a device that provides an indication of the intensity of the force that is applied by the tensioning device.

BACKGROUND OF THE INVENTION A conveyor belt typically includes one or more scraper units that are constructed and located along the belt to remove or eliminate the remnants of the materials transported by the conveyor belt, which adhere to the surface of the belt. . Frequently, a scraper unit includes one or more scraper blades arranged across the width of the conveyor belt. The blades are mounted on a support arm or arms which are fixed to a rotating support shaft and which extend from it located or mounted transversely. The rotation of the transverse support arrow brings the scraper blade or blades towards a contact position and towards an out position P1472 / 98MX contact with the surface of the band. The cleaning efficiency of the scraper unit depends on the magnitude of the force exerted by the scraper blade against the surface of the belt. If the contact force is too great, the scraper blade will wear out prematurely. On the other hand, if the contact force is very weak, the blade will not efficiently clean the belt. To adjust the pressure with which a scraper blade makes contact with the surface of the conveyor belt, torsional coil springs, torsion rod springs, air cylinders, hydraulic cylinders and similar devices are used. In pneumatic and hydraulic systems, a manometer provides an indication that can be correlated with the intensity of the force applied. It would be highly desirable to have a tensioning device for a band scraper unit that provides an instantaneous indication that can be easily used to reproducibly set or adjust the intensity of force with which the scraper blade contacts the web surface.

SUMMARY OF THE INVENTION In accordance with the present invention, a self-indicating tension device is provided for adjusting the contact force of a scraper sheet against P1472 / 98MX the surface of a conveyor belt. The self-indicating tensioning device according to this invention has a rotary arrow supporting the scraper blade in such a way that rotation of the rotating shaft vertically displaces the scraper blade. A flat spring is coupled at one end to the rotating shaft and at the other end to an adjustment mechanism. The adjustment mechanism exerts a force on the flat spring which, in this way, applies a torque or torque to the rotating shaft. The end coupled to the adjusting device can be moved with respect to the fixed end to the rotating shaft. An indicator rod extends radially from the rotating shaft with one end fixed to the rotary shaft and the other end is free so that the force exerted on the plane spring does not cause deflection of the indicator rod. A graduated indicator plate is connected or attached to the moving end of the flat spring and can be moved with respect to the indicator rod. As the flat spring flexes in response to the application of force to it, the displacement of the indicator plate graduated with respect to the free end of the indicator rod provides an indication of the intensity or amount of force exerted on the flat spring, the intensity of the torque or torque applied to the rotating shaft or the intensity of the P1472 / 98 X force with which the scraper blade makes contact with the conveyor belt.BRIEF DESCRIPTION OF THE DRAWINGS The preceding summary of the invention, as well as the following description of a preferred embodiment thereof, will be better understood by reference to the drawings, wherein: Figure 1 is a perspective view showing a portion of a conveyor belt and a scraper unit used in connection therewith in accordance with the present invention; Figure 2 is a perspective view showing a tensioning device in accordance with the present invention for use with the scraper unit shown in Figure 1; Figure 3 is an elevation view of a spring subunit and indicator of the tension device shown in Figure 2, when the mechanism applying the torque or torque is in the neutral position; Figure 4 is an elevation view of the spring subunit and indicator of the tension device shown in Figure 3, showing the manner in which the leaf spring moves when a force is applied thereto.

P1472 / 98MX DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to Figure 1, a portion of a conveyor belt 10 traveling in the direction indicated by the arrow A is shown. A belt cleaner unit 12 is located adjacent to the belt 10. belt cleaning unit 12 includes a scraper unit 14 and a tension or tensioning unit 16 mechanically linked to scraper unit 14. Scraper unit 14 includes a scraper blade 17 which is located below conveyor belt 10 and which is kept in contact with it for cleaning the remnants of the material that is transported by the conveyor belt 10. The scraper blade 17 is mounted on a sheet support bar 18 that extends the width of the conveyor belt 10. The ends of the bar 18 sheet supports engage with receptacles or openings in the ends of the blade of a pair of pivot arms that link to the leaf support bar with n a rotary transverse arrow 20 which also extends the width of the conveyor belt 10 in parallel relation to the support bar 18 of the leaf. The rotary transverse arrow 20 has a generally polygonal cross section, preferably square. For clarity, only the near side of the pivot arm 21, its blade end 22 and its arrow end 23 are shown in Figure 1.

P1472 / 98MX transversal. The transverse arrow end 23. The end 23 of the transverse arrow of the pivot arm 21 is formed to engage the transverse arrow 20 so that it can rotate therewith. To this end, the ends of the transverse arrow of the pivot arms include through the same openings of polygonal shape. In the embodiment shown in Figure 1, the end 23 of the transverse arrow has therein a square opening for receiving the square transverse arrow 20. An extension 24 extends from the near end of the transverse arrow 20 and through a support bracket 26 which is mounted to the supporting frame of the conveyor belt 10. A similar arrangement (not shown) is provided at the far end of the transverse arrow 20. The extensions have polygonal cross sections that coincide with that of the transverse arrow 20 although they are smaller. A connector block 28 is mounted on the outward end of the extension 24, so that it can rotate therewith. In the embodiment shown in Figure 3, the connector block 28 has a square opening therein for receiving the square extension arrow 24. Extending from one side of the connector block 28 is a flat or leaf spring 30 and an indicator rod 32 that are insured to a P1472 / 98MX bracket 34 in the connector block 28. An indicator plate 36 is fixed to the end of the flat spring 30 which is distal to the connector block 28. The indicator plate 36 has a plurality of graduations formed therein. The free end of the indicator rod 32 is located adjacent to the indicator plate 36. The flat spring 30 is preferably machined from flat steel stock for spring. Because conveyor belts of different widths require different amounts or amounts of force on the scraper blade for effective cleaning, the force applied to the flat spring 30 will depend on the width of the band with which it is used. The thickness of the flat spring steel stock is selected based on the amount or amount of the force that will be exerted on the spring 30 and the maximum amount of deflection that can be tolerated by the spring 30 when subjected to tension. To support the use of various spring thicknesses, the bracket 34 has a fixed space 37 which is dimensioned to receive a spring having the maximum thickness desired. When using thinner springs, one or more shims are used to fill the space of the bracket and ensure a tight fit. The flat spring 30 and any necessary shims are secured to the bracket 34 with a suitable fastener, preferably a unit P1472 / 98MX nut and screw 39. The tension unit 16 is connected between a fixed structure 23 such as the band support frame and the movable end of the spring 30. The tension unit 16 operates or works to move the mobile end of the spring 30, thereby imparting a torque or torque to pivot the transverse shaft 20 to lift the scraper blade 17 toward a coupling with the conveyor belt 10 or to lower it toward a decoupling therefrom. Referring now to Figure 2, a mounting bracket 38 is attached to a convenient fixed structure such as the support frame of the conveyor. An anchor fork 40 is connected to the mounting bracket 38. An anchor rod 42 is coupled to the anchor fork 40 with a nut and screw unit 44. The anchor rod 42 has a threaded end 45 that is screwed or screwed on. at an end 46a of a barrel 48 that is part of a force actuator 50. A drive rod 52 has a threaded end 54 that is threaded or screwed into the opposite end 46b of the barrel 48. The non-threaded end of the rod drive 52 is coupled to a drive fork 56 with a nut and screw unit 58. The drive fork 56 is secured to the end of the flat spring 30 by a P1472 / 98MX suitable medium. The force actuator 50 includes a handle 60 and a ratchet mechanism 62 for rotating the barrel 48. The thread on the threaded end 45 of the anchor rod 42 is opposite that of the threaded end 54 of the drive rod 52. Therefore, when the force-actuating barrel 48 is rotated, the driving rod 52 moves in approach or away from the anchor rod 42 depending on the direction of rotation of the force-actuating barrel 48. According to the barrel force actuator 48 rotates, an attraction or pushing force is applied to the end of the spring 30 through the drive fork 56. The force thus applied to the end of the spring 30 causes a torque to be applied to the connector block 28. and, in turn, to the transverse arrow 20. This torque causes the transverse arrow 20 to rotate thus bringing the scraper blade into engagement with the conveyor belt 10 or pulling it out of said coupling. nto. As more force is applied to the spring 30, a greater torque will be applied to the transverse arrow 20, thereby causing the scraper blade 17 to contact the conveyor belt 10 with a proportionally greater force. However, when the scraper blade 17 is in contact with the web 10, the transverse arrow 20, which P1472 / 98MX is formed of a rigid material such as steel, it will resist the torque applied to it through the connector block 28. Consequently, the movable end of the spring 30 will flex in the direction of the force applied thereto as shown in Figure 4. The indicator rod 32 connected to the connector block 28 will not flex as force is applied to the spring 30. The indicator plate 36 fixed to the spring 30 will move with respect to the free end of the indicator rod 32 according to the end of the Pier 30 flexes. The graduation that is then adjacent to the free end of the indicator rod 32 provides an indication of the amount or amount of the torque that is being applied to the connector block 28 and the transverse arrow 20. The graduations on the indicator plate 36 can be calibrated to provide an indication of the amount of force with which the scraper blade 17 contacts the web surface. Alternatively, the graduations on the rating plate can be calibrated to indicate the amount of torque applied to the rotating shaft or the amount of force with which the scraper blade contacts the conveyor belt. It will be appreciated that the arrangement described provides a significant advantage in providing the ability to set or adjust and re-adjust or reproducibly fix the force of the blade.

P1472 / 98MX scraper by simply operating the force actuator 30 until the desired graduation on the indicator plate 36 is adjacent to the end of the indicator rod 32. Those skilled in the art will recognize that changes or modifications can be made to the embodiments described above without deviating of the broad concept of the invention. Therefore, it should be understood that this invention is not limited to the particular embodiments described therein but is intended to include all changes and modifications that are within the scope and spirit of the invention as set forth in the following claims.

P1472 / 98MX

Claims (5)

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A self-indicating tension device for adjusting the contact force of a scraper blade against the The surface of an endless conveyor belt, the tensioning device comprises: a rotary arrow supporting the scraper blade in such a way that the rotation of the rotating shaft results in the displacement of the scraper blade toward or away from the belt; an elongated flat spring coupled at one end to the rotating shaft; an adjusting mechanism coupled to a second end of the distal plane spring of the rotary shaft to move the second end of the flat spring; an indicator rod extending radially from the rotating shaft and having one end fixed to the rotating shaft and the other end free; an indicator plate fixed to the second end of the flat spring; the flat spring is adapted to flex in response to the application of force by the
1. P1472 / 98MX adjustment device and cause the displacement of the graduated indicator plate with respect to the free end of the indicator rod.
2. 2. The tensioning device according to claim 1, wherein the indicating device comprises a pointer or pointer. The tensioning device according to claim 1, wherein the adjustment device comprises a screw tensioner with two threaded links on the contrary, one of the links is coupled to a support structure of the conveyor and the other end is connected to the flat spring . The tensioning device according to claim 3, wherein the screw tensioner comprises a ratchet for rotating the threaded links to the contrary. The tensioning device according to claim 1, wherein the fixed end of the indicator rod is located adjacent the point of connection of the elongated flat spring to the rotating shaft. P1472 / 98MX