BELT GUIDE

Abstract: The invention relates to a belt guide for short belt conveyors (1) in which an endless belt is passed over rollers (3, 4) at the ends of the conveyor. A plurality of glide strips (10) which extend generally in the direction of belt movement (7) beneath the upper run of the belt and over a stationary plane or surface (12). They are pivotal along the plane (12) about a respective pivot (11) in the proximity of the conveyor input end (8) and mutually connected for common angular movement around the pivots (11). The upper surface of respective glide strips (10) is proud of the common tangential plane of the end-rollers (3, 4) so that there can be generated between the glide strips (10) and the conveyor belt a contact pressure which is sufficiently great for the frictional force that acts laterall between the strips and the belt to enable lateral displacement of the belt in response to an angular change in the position of the glide strips (10).

Description: BELT GUIDE The present invention relates to a belt guide for short belt conveyors of the kind with which an endless belt runs over rollers at the ends of the conveyor. It has long been generally recognized that it is very difficult to guide an endless belt whose width is greater than the length of the conveyor, ie when the ratio of the belt width to the distance between the conveyor end-rollers is greater than 1.6. Such belt conveyors find use in belt weighing machines in the fibreboard industry for instance, and their use in other industrial applications is not unusual. The problem with such short belts resides in the tendency of the belt to be driven towards one side of the conveyor. Attempts have been made to guide such belts mechani- cally, although without much success. The object of the invention is to solve this problem and to provide a belt guide for short conveyors which will effectively eliminate such sideways movement of the belt. This object is achieved with an inventive belt guide having the characteristic features set forth in the following claims. The invention will now be described in more detail with reference to the accompanying drawing which illustrates in perspective a belt conveyor equipped with a belt guide according to the invention, although the belt itself has been omitted from the drawing for the sake of clarity. The illustrated belt conveyor has a width which is several times greater than its length and is comprised of a fixed body 2 on which an endless belt is guided, (the belt not being shown for the sake of clarity) . The belt passes over end-rollers which in the illustrated case have the form of roller ramps 3 and 4, wherein one roller ramp 3 is driven and the other is not. The ramp roller 3 is driven by an electric motor 5 through the medium of a drive belt 5. The direction of belt movement is shown by the arrow 7. Consequently, the conveyor input end is referenced 8 and its output end is referenced 9. The conveyor 1 includes a plurality of glide strips 10 which function to guide the conveyor belt laterally on the conveyor and each of which is pivotal about a respective pivot 11. The pivots 11 are disposed on a stationary surface 12 beneath the upper run of the conveyor belt and in the proximity of the input end 8. The glide strips are mutually connected by a rod or bar 13 which extends perpendicularly to the direction of belt movement and which is pivotally connected to all strips 11 at a distance therefrom in the direction of belt movement 7. The rod 13 is drivingly connected to a control means 14 whereby the rod is able to move reciprocatingly, transversely to the direction of belt movement. This alternating movement of the rod, as shown by the double-headed arrow 15, causes the glide strips 10 to execute an angle-changing movement along the plane 12, as shown by the double-headed arrows 16. The upper surfaces of the glide strips 10 are proud of the tangential plane of the end-rollers 3 and 4, such as to raise the level of the conveyor belt in relation to the end-rollers. In this way there is generated between the glide strips 10 and the conveyor belt a contact pressure which is sufficiently large for the frictional force that acts laterally between said strips and said belt to enable lateral displacement of the belt in response to the angular change of the glide strips . This contact pressure is created by the tension in the belt and/or the weight of the goods being transported. Thus, the belt can be readily caused to move sideways in the movement direction of the rod 13, by changing the angle of the glide strips 10. The later position of the conveyor belt can be sensed in a known manner with an analog angle indicator which regulates the control means 14 together with a pulsating PID-regulator. Naturally, other known control systems can be used, for instance pneumatic or hydraulic control systems with propor¬ tional valves as angle indicators. The inventive belt guide enables short conveyor belts to be guided in a particularly simple manner. The inventive belt guide is also light in weight in comparison to other belt guide means that have been proposed.

Claims: CLAIMS 1. A belt guide for short belt conveyors (1) in which an endless belt is passed over rollers (3, 4) at the ends of the conveyor, characterized by a plurality of glide strips (10) which extend generally in the direction of belt movement (7) beneath the upper run of the belt and over a stationary plane or surface (12) and which are pivotal along said plane (12) about a respective pivot (11) in the proximity of the conveyor input end (8) and mutually connected for common angular movement around said pivots (11) , wherein the upper surface of respective glide strips (10) is proud of the common tangential plane of the end-rollers (3, 4) so as to generate between the glide strips (10) and the conveyor belt a contact pressure which is sufficiently great for the frictional force that acts laterally between said strips and said belt to enable lateral displacement of the belt in response to an angular change in the position of the glide strips (10) . 2. A belt guide according to Claim 1, characterized in that said common connection of the glide strips (10) is achieved with the aid of rod (13) which extends perpendicularly to the direction of belt movement (7) and which is pivotally connected all strips (10) and displaceable in its longitudinal direction and displaceably connected to a control means (14) . 3. A belt guide according to Claim 2, characterized in that the control means (14) is adapted for control by a belt- position sensor and a pulsating PID-regulator.

Inventors: PIHLSTROEM VINCENT, PIHLSTROEM, VINCENT
Applicants: PIHLSTROEM VINCENT, SUNDS DEFIBRATOR IND AB, PIHLSTROEM, VINCENT, SUNDS DEFIBRATOR INDUSTRIES AB
Application year: 1996
Main classification: B65G15
IPC codes: B65G15