GB2182905A

GB2182905A - Apparatus for controlling the position of webs or conveyor belts relative to associated guide or deflecting rollers

Info

Publication number: GB2182905A
Application number: GB08626403A
Authority: GB
Inventors: Friedhelm Brinkmeier
Original assignee: Windmoeller and Hoelscher KG
Current assignee: Windmoeller and Hoelscher KG
Priority date: 1985-11-18
Filing date: 1986-11-05
Publication date: 1987-05-28
Also published as: GB8626403D0; DE3540881A1; JPS62121165A; JPH09217U; FR2590242A1; DE3540881C2; FR2590242B1; GB2182905B

Abstract

Apparatus for controlling the position of webs or endless conveyor belts (1) in a lateral direction relative to associated guide and/or deflecting rollers comprises an aligning roller (4), freely rotatably mounted in a guide fork (12) pivoted on a pivot (14) which is at right angles to the plane of the web (1). Said guide fork (12) is connected by transmitting means (20, 27) to scanning rollers (25, 26) which scan the side edges of the web (1) and in response to a lateral wandering of the web adjust the aligning roller (4) in a restoring sense. The scanning rollers (25, 26) are mounted on a carrier (20), which extends approximately parallel to the aligning roller (4), and is mounted for movement in the longitudinal direction of the carrier. The carrier (20) is pivoted at least at one end portion by a link (27) to that journal (9) of the axle (7) that is disposed on the same side of the web (1). The link (27) is outwardly inclined from the point at which it is pivoted to the carrier (20). The link when viewed in the direction of travel of the web includes with the edge of the web an angle which is smaller than 90 DEG . <IMAGE>

Description

SPECIFICATION Apparatus for controlling the position of webs or conveyor belts relative to associated guide or deflecting rollers This invention relates to apparatus for controlling the position of webs or endless conveyor belts in a lateral direction relative to associated guide and/or deflecting rollers, comprising a freely rotatably mounted aligning roller, which is moved into engagementwith theweb and is freely rotatably moun ted in a guide fork orthe like, which in an inter- mediate portion ofthe aligning roller is pivoted on a pivotwhich is at right angles to the plane of the web, wherein said guide fork is connected by transmitting means to scanning rollers which scan the side edges ofthe weg and in response to a lateral wandering of the web adjustthe aligning roller in a restoring sense.

Conveyor belts, particularly belts of double belt conveyors, as well as webs fed over guide rollers and deflecting rollers, may perform an undesired lateral wandering relative to associated guide rollers and/or deflecting rollers and mustthen be restored sothata troublefreetravel in alignment with the guide rollers and deflecting rollers will be ensured.

German Patent Publication 1246542 describes an apparatus which is of the kind described hereinbefore and in which the rollersforscanning the oblique edges of the webs or belts consist of control rollers, which are mounted in the machine frame on freely rotatable shafts and are operatively interconnected bysplinedspurgears.Oneoftheshafts consists of s screw on which a nut is mounted, which is pivoted to one end of a bell crank lever, which is pivoted at its other end to a push rod, which imparts to the aligning roller a pivotoal movement about a vertical central transverse axis. That known apparatus is complicated and expensive because it comprises numerous movable parts. The friction throughoutthe system and the inertia of the control rollers prevent a sensitive response and there is also a risk of hunting.

East German Patent Specification 47,845 describes an apparatus which serves to align endless conveyor belts and in which the aligning roller is mounted adjacent to the crosspiece of a fork, which has prongs that constitute control levers, which carry scanning rollers. The prongs must either have a very large length so that they can be adjusted by small forces exerted by the edges ofthe belts, or shorter control levers must be subjected to strong adjusting forces, which may damage the edges.

Published German Application 2734325 describes an apparatus in which sensorsforscanningthe edges of the web transmit the required adjusting forces by means of levers and by an optional linkand another lever to an aligning roller. In that apparatus the magnitude ofthe adjusting forces which can be exerted to impart a pivotal movement to the aligning roller will also depend on the length of the levers so that the apparatus must have a relatively large length ifthe aligning roller isto be pivotally moved by small forces which are transmitted from the edges of the web to the sensors.

For this reason it is an object of the invention to provide an apparatus which is ofthe kind described first hereinbefore and which has a short length and permits the aligning rollerto be adjusted only by mechanical means and without a transmission of substantial forces from the wandering edges of the weborconveyorbelttothescanning rollers.

In accordance with the invention that object is ac complishedinthatthescanning rollers (25,26) are mounted on a carrier (20), which extends approximately parallel to the aligning roller (14) and is mounted in the machine frame (3)fora movementin the longitudinal direction of the carrier, the carrier (20) is pivoted at least at one end portion by a link (27) to that journal (9) of the axle (7) that is disposed on the same side oftheweb (1 ) orto a journal ofthe aligning roller, the link (27) is outwardly inclined from the point at which it is pivoted to the carrier (20) and the link (27) when viewed in the direction of travel of the web (1) includes with the edge ofthe web an acute angle which is smallerthan 90 .

Because the link is connected by means which are similarto a toggle joint, transverse displacements of the carrierwill cause strong adjusting forces to be exerted on the aligning roller and the mechanical advantagewill increase as the angle decreases. In the apparatus in accordance with the invention even small pressure forces exerted by the edges ofthe weborconveyorbeltonthescanningrollerswill re sultin an adjustment ofthe aligning rollersothat damage to the edges of the web or belt need not be feared. For this reason the apparatus in accordance with the invention can be used also for relativelythin webs, which can exert at their edges only small pressure forces on the scanning rollers.

Thatjournal associated with the aligning rollerto which the link is pivoted is suitably extended. The journals at both ends ofthe aligning roller may be supported by means of rolling element bearings on flatguidewaysofthe machineframein orderto permit a low4riction adjustment about the central pivotal axis.

The carrier is suitably engaged on its sides by rolling element bearings for guiding the carrierwith low friction. Obviously the carrier may additionally be supported by rolling element bearings.

The link may alternatively be pivoted to the guide forkorthe like orto an arm which is connected to the guidefork.

In a suitable arrangement, a switch, which is fixed to the frame, is provided adjacent to the carrier and in response to an excessive displacement of the carrier is actuated by the latter to stop the means for driving the web or belt. That switch will not be actuated unless the web has wandered to such a large extentthata correction cannot be effected by an adjust mentofthealigning roller alone.

An illustrative embodiment of the invention will now be explained more in detail with reference to the drawing, in which Figure lisa top plan view showing an apparatus for controlling the position of endless conveyor belts and Figure2 is a sectional view taken along line I-I in Figure 1 and showing the apparatus.

The endless conveyor belt 1 travels in the direction indicated by the arrow 2 overthe aligning roller4, which is mounted in the machine frame 3. By means of rolling element bearings 5, 6the aligning roller4is freely rotatably mounted on an axle 7. The journals 8, 9oftheaxle7protrudefromthealigning rollerand are held in the prongs 10,11 ofthe guidefork 12. The guide fork 12 comprises a crosspiece 13, which is parallel to the aligning roller4and which in its intermediate portion is pivoted on the pivot 14, which is fixed to the frame and extends approximately at right angles to the conveyor belt 1.

Outside the prongs 10,11 ofthe guidefork 12, rolling element bearings 15, l6aresecuredtothejour- nals 8,9. The outer races ofthe bearings 15, 16 are supportedonflatguideways 17,l8ofthemachine frame.

Acarrier 20 is mounted in the machine frame and extends parallel to the aligning roller 4 and is freely displaceable in its axial direction.The carrier 20 is guided between rolling element bearings 21 to 24 and may additionally be supported also on rolling element bearings. The carrier 20 is provided with scanning rollers 25,26, which are mounted on axles extending at right angles to the plane ofthe web. The scanning rollers 25, 26 arein gentle contactwiththe edges ofthe web 1 and scan said edges.

On the side which is the underside in Figure 1,the carrier 20 is pivoted to a link 27, which is pivoted at its other end to the extended journal 9. When viewed in the direction oftravel ofthe conveyor belt 1 the link 27 includes with the edge of the belt 1 an acute angle, which is smaller than 90 .

The carrier 20 is provided with a radial arm 30, which in case of an excessive wandering in one direction or the other actuates a switch 31 for stopping the driveforthe belt.

Claims

1. Apparatus for controlling the position of webs or endless conveyor belts in a lateral direction relat iveto associated guide and/or deflecting rollers, comprising a freely rotatably mounted aligning roller, which is moved into engagement with the web and isfreelyrotatably mounted in a guideforkorthe like, which in an intermediate portion ofthe aligning roller is pivoted on a pivotwhich is at right angles to the plane of the web, wherein said guide fork is connected bytransmitting means to scanning rollers which scan the side edges ofthe web and in re sponse to a lateral wandering ofthe web adjustthe aligning roller in a restoring sense, characterized in thatthe scanning rollers (25,26) are mounted on a carrier (20), which extends approximately parallel to the aligning roller (14) and is mounted in the machine frame (3) for a movement in the longitudinal direction ofthe carrier, the carrier (20) is pivoted at least at one end portion by a link (27) to thatjournal (9) of the axle (7) that is disposed on the same side oftheweb (1) orto a journal ofthe aligning roller, the link (27) is outwardly inclined from the point at which it is pivoted to the carrier (20) and the link (27) when viewed in the direction of travel ofthe web (1) includes with the edge ofthe web an acute angle which issmallerthan 90 .

2. Apparatus according to claim 1, characterized in thatthatjournal associated with the aligning roller to which the link is pivoted is extended.

3. Apparatus according to claim 1 or2,characterized in that the journals disposed at both ends ofthe aligning roller are supported by rolling element bearings on flat guideways ofthe machine frame.

4. Apparatus according to any of claims 1 to 3, characterized in that rolling element bearings for guiding the carrierwith low friction extend on both sides ofthe carrier.

5. Apparatus according to any of claims 1 to 4, characterized in that the carrier (20) is supported by rolling element bearings.

6. Apparatus according to claim 1, characterized in thatthe link is pivoted tothe guideforkorthe like orto an arm which is connected to the guide fork.

7. Apparatus according to any of claims 1 to 6, characterized in that a switch, which is fixed to the frame, is provided adjacenttothecarrierand in re sponse to an excessive displacement ofthe carrier is actuated by the latterto stop the meansfordriving the web or belt.

8. Apparatus for controlling the position ofwebs or endless belts in a lateral direction relative to associated guide rollers and/or deflecting rollers, substantially as described hereinbefore with refer encetothedrawing.