GB2141988A

GB2141988A - Clamping device for conveyor belts

Info

Publication number: GB2141988A
Application number: GB08321198A
Authority: GB
Inventors: Harlad Fudickar; Peter Theis
Original assignee: Wagener Schwelm GmbH and Co
Current assignee: Wagener Schwelm GmbH and Co
Priority date: 1983-06-23
Filing date: 1983-08-05
Publication date: 1985-01-09
Also published as: GB8321198D0; DE3322562C1; GB2141988B; CA1222473A

Abstract

A clamping device (1) for clamping a conveyor belt (2) with a prescribed clamping force has an upper crossbar (3), a lower crossbar (4), gripping bolts (5) and a mounting (6) by means of which clamping device as a whole, including the clamped conveyor belt (2), can be anchored and/or supported. Both of the crossbars (3, 4) having a clamping bar (7, 8) for contacting the conveyor belt, with clearance holes (9) in the clamping bars through which the gripping bolts (5) are inserted, at least one of the clamping bars (7) being supported from the associated crossbar (3) by hydraulic pressurising means (10) which sets up or transmits the clamping force, and the mount serving to guide the clamping bars. <IMAGE>

Description

SPECIFICATION Clamping device for conveyor belts This invention reiates to a clamping device for clamping a conveyor belt with a prescribed clamping force (for use in conveyor-belt traction, braking, guiding and tensioning mechanisms and the like) being of the type having an upper crossbar, a lower crossbar, gripping bolts, and a mounting by means of which the clamping device as a whole, including the clamped conveyor belt, can be anchored and/ or supported. The gripping bolts can be actuated by means of a screwed-on tightening nut for example, and set up a prescribed clamping force when tightened by means of a torque wrench at a prescribed tightening torque setting. The gripping bolts can however also be actuated by other means, for example hydraulically.

In known clamping devices of this type, the crossbars simultaneously act as clamping bars, which are urged down on to the conveyor belt to be clamped. Since the gripping bolts act at the ends of the crossbars, the latter undergo a more or less arcuate elastic deformation, so that the clamping force and hence the belt holding force is not uniformly distributed over the length of the crossbars.

The edges of the conveyor belt are clamped more tightly than the middle regions, and frequently exhibit local damage by reason of the excessive local clamping forces at the edges. The mounting itself is attached to the crossbars. The result of this is that the crossbars are subjected to a complex stress pattern in use, which can impair the stability of the clamping device when high tensile forces are applied to the clamped conveyor belt, and can lead to dangerous stability problems.

The object of the invention is to provide a clamping device of the type initially described, in which, on the one hand, the belt holding force is distributed very uniformly over the entire width of the clamped conveyor belt, and, on the other hand, disadvantageous stability problems and unpredictable stress patterns no longer arise.

According to the present invention, in a clamping device of the type initially described both of the crossbars have a clamping bar for contacting the conveyor belt, the clamping bars have holes through which the gripping bolts are inserted, at least one of the clamping bars is supported from the associated crossbar by hydraulic pressurising means which sets up or transmits the clamping force, and the mounting serves to guide the clamping bars.

In order to minimise the weight of such a clamping device when high forces are involved, it is preferable to use box sections for the crossbars and channel sections for the clamping bars. In order to separate the belt holding forces which secure a clamped conveyor belt, on the one hand, cleanly from the actuating force for the clamping bars, on the other hand, it is preferred that the gripping bolts are inserted through clearance holes in the clamping bars. It is self-evident that with one of the clamping bars supported from the associated crossbar with the aid of the hydraulic unit, in such a manner that the deformations in the clamping bars, set up by the belt holding forces, are not transmitted to the crossbars of the hydraulic unit.

The form of the hydraulic unit in the device of the invention is in principle optional. Thus, the hydraulic unit can consist of cylinder-andpiston units spaced over the length of the associated crossbar, and either connected to a pump or adapted to be pressurised by tightening the gripping bolts. In the latter case, it will be evident that the cylinder-and-piston units on each crossbar are combined into a closed hudraulic system or systems. Preferably, however, the hydraulic unit comprises hydraulic hoses of deformable cross-section, and a deflection compensator, the hydraulic hoses being connected to a pump or being pressurised by tightening the gripping bolts, being outstanding for the very uniform belt holding force it sets up over the entire width of the conveyor belt.Arrangements incorporating hydraulic hoses and a bending-line compensator are known (see GB-PS 2 082 966A) but they can be used to particular advantage in the clamping devices in accordance with the invention.

The accruing advantages are to be seen in that the belt holding forces, on the one hand, and the clamping forces applied through the hydraulic unit, on the other hand, are cleanly separated one from the other. The deformations of the clamping bar or bars under the belt holding forces are not transmitted to the associated hydraulic unit or the associated crossbars. This makes the loading conditions predictable, suppressing disadvantageous three-dimension stress patterns and consequent stability problems. Accordingly, the clamping device of the invention can be made particularly light in weight yet functionally reliable.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a clamping device in accordance with the invention, containing a clamped conveyor belt; and Figure 2 is a diagrammatic cross-section, on a much larger scale than Fig. 1, through the area occupied by the clamped conveyor belt.

The clamping device 1 shown in the Figures is intended for the clamping of conveyor belts 2 with a prescribed clamping force. It can be used in conveyor-belt traction, braking, guiding, and tensioning mechanisms and the like. In basic construction, it incorporates an upper crossbar 3, a lower crossbar 4, gripping bolts 5 and a mounting 6 by means of which the clamping device as a whole, including the clamped conveyor belt 2, can be anchored and/or supported.

The crossbars 3, 4 have clamping bars 7, 8 respectively for contacting the conveyor belt and having holes 9 through which the gripping bolts 5 are inserted. The clamping bar 7 is supported from the associated crossbar 3 by a hyudraulic unit 10 which sets up or transmits the clamping force. Fig. 1 shows that the mounting 6 has a bracket 11 which guides the clamping bars 7 and 8. Alternatively, however, the clamping bars 7, 8 could be fitted with lugs 1 2 for attachment to anchoring cables 1 3 as shown by broken lines extending to the left in Fig. 1. The arrangement is such that deformations of either clamping bar 7 or 8, resulting from the belt holding forces, are not transmitted disadvantageously to the associated crossbar 3 or 4 and the corresponding hydraulic unit 10. This ensures that the belt holding forces on the one hand and the clamping forces set up through the hydraulic unit on the other hand are separated one from the other, and specific stress patterns act on the clampingW device 1 as a whole.

The crossbars 3, 4 can be seen as being formed by multiple box sections and the clamping bars 7, 8 by channel sections. The gripping bolts 5 are inserted through clearance holes 9 in the clamping bars 7, 8 to maintain the described force separation.

The hydraulic unit 10 comprises hydraulic hoses 14 of deformable cross-section, and a deflection compensator 1 5. The hydraulic hoses 14 can be connected to a pump (by means not shown) or can be pressurised by tightening the gripping bolts, in the known manner of GB-PS 2 082 966 A.

Claims

1. A clamping device for clamping a conveyor belt with a prescribed clamping force comprises an upper crossbar, a lower crossbar, gripping bolts, and a mounting by means of which the clamping device as a whole, including the clamped conveyor belt, can be anchored and/or supported, both of the crossbars having a clamping bar for contacting the conveyor belt, both of the clamping bars having holes through which the gripping bolts are inserted, at least one of the clamping bars being supported from the associated crossbar by hydraulic pressurising means which sets up or transmits the clamping force, and the mounting serving to guide the clamping bars.

2. A clamping device as in Claim 1, wherein the crossbars are formed by box sections and the clamping bars by channel sections.

3. A clamping device as in either of Claims 1 and 2, wherein the gripping bolts are inserted through clearance holes in the clamping bars.

4. A clamping device as in any one of Claims 1 to 3, wherein the hydraulic pressurising means consists of cylinder-and-piston units spaced over the length of the associated crossbar and either connected to a pump or adapted to be pressurised by tightening the gripping bolts.

5. A clamping device as in any one of Claims 1 to 3, wherein the hydraulic pressuring means comprises hydraulic hoses of deformable cross-section, and a deflection compensator, the hydraulic hoses being connected to a pump or being adapted to be pressurised by tightening the gripping bolts.

10. A clamping device for clamping a conveyor belt with a prescribed clamping force substantially has hereinbefore described with reference to the accompanying drawings.