WO2013186790A1

WO2013186790A1 - "3-d belt tracking assembly"

Info

Publication number: WO2013186790A1
Application number: PCT/IN2013/000365
Authority: WO
Inventors: Rajesh John; Elumalai MANIMARAN
Original assignee: Thejo Engineering Limited
Priority date: 2012-06-11
Filing date: 2013-06-10
Publication date: 2013-12-19

Abstract

A 3-D belt tracking assembly to bring the mis-tracked conveyor belt (24) back on track is disclosed herein. The 3-D belt tracking assembly comprises a support frame assembly fixed across conveyor belt width to support conveyor belt, a sensing assembly to detect any deviation of the belt from its central path on conveyor structure, a plate (7), a tracking idler (25) and a connecting link mechanism/linkage. When guide rollers of the sensing assembly move towards mis-tracked belt direction, causing ball bush of the connecting link mechanism/linkage to swivel the plate (7). This further causing the tracking idler (25) to swivel and tilt, making the plate and the tracking idler (25) to raise on the side of mis-tracked belt, thereby steering mis-tracked belt back to track.

Description

"3-D BELT TRACKING ASSEMBLY

FIELD OF INVENTION:

The present invention relates to the field of conveyor belt tracking devices. More particularly, the present invention relates to 3 -D assembly which steers a mis-tracked conveyor belt back on track.

BACKGROUND & PRIOR ART:

Conveyors are one of the most economical forms of transport of bulk material items. Mistracking is a common problem of conveyor belts. Some of the commons causes of belt mist racking are improper chute design, improper loading, misaligned joint, alignment of various conveyor parts like pulleys, idlers etc., Frozen Idlers and Conveyor Carryback.

Sometimes, as it is not practical to rectify the above issues, tracking devices are used to track the belt.

The tracking of the belt is achieved by swiveling the tracking idler this can be achieved by

(i) using a guide rollers and a linkage mechanism to swivel the tracking idler into position,

(ii) using concentric drums with the inner drum being able to swivel about a shaft that is fixed. The outer drum rotates about the inner shaft.

The present invention uses guide rollers and linkage mechanism to swivel the tracking idler into position.

The traction action to guide the belt onto to the conveyor centre is generally made by the swiveling the tracking idler so that its axis changes from being substantially perpendicular to the conveyor belt movement direction to a position in which one side is moved forward and the other side is pulled back. The side moved forward is the side to which the belt is mistracked. The change in idler orientation forces the belt to be tracked to centre. Most tracking units stop with this action. The change is orientation is only because of swivel which is substantially in the horizontal plane. There is no change in the vertical plane of the tracking idler.

US6131726 discloses a belt steering assembly in which two guide rollers sense the mistracking of the belt and by means of a link mechanism the belt is tracked back. The entire tracking action is made by the swiveling action of the idler. There is also a brief given about how the system can be modified to make the tracking reversible.

US 6186317B 1 describes a reversible belt tracking system which essentially is similar to US 6131726 but has two guide sensing systems one on either side and a switching mechanism to engage the relevant sensing arm depending on the direction of the belt travel.

US 7669709 simplifies the linkage mechanism describes in US 6131726 however essentially the tracking action remains same ie the sensing rollers transmit a swiveling action to the tracking idler.

US 53558098 describes a belt tracking system which combines both swiveling and tilting action. Though the system combines both swiveling action and titling action. This tracking mechanism has some inherent disadvantages. The guide rollers are fixed to the tracking idler assembly and hence swivels when the tracking idlers are swiveled. When one edge of the belt contacts a guide roller, the guide rollers are swiveled along with the tracking idlers. Thus, the distance between the guide rollers measured along the belt width decreases as the guide rollers swivel. Since the transverse distance (i.e. distance along the belt width) between the guide is reduced when swiveling, the guide rollers need to be kept at a reasonable distance to avoid guide roller at the far end from interfering into the far edge of the belt. As a result the tracker will have a delayed response when the belt is mis-tracked.

The other major problem is that the delayed response increases the chances of the tracker getting stuck due to accumulation of fugitive material, dust in the interim period. Also since the arms need to be fixed onto the steering mechanism it will be difficult to use the existing idler of the conveyor.

In view of the above, it is the object of the present invention to provide a 3-D belt tracking assembly that tracks by combining both swiveling, i.e. movement along the horizontal plane, and tilting, i.e. movement on vertical plane, of the tracking idlers (3Dimenional tracking).

The other modifications in the assembly that overcomes the drawbacks of the prior arts are appended below in the specification.

SUMMARY OF INVENTION:

The present invention discloses a 3-D belt tracking assembly to bring the mis-tracked conveyor belt back on track. The 3-D belt tracking assembly comprises (i) a support frame assembly fixed across conveyor belt width to support conveyor belt consisting of a support beam having plurality of telescopic legs bolted/fastened onto a conveyor stringer, a sleeve passing through centre of the support beam, and a plurality of equal length arms are pivotally hinged from the support beam rotatable about their respective hinge thereby tracing an arc trajectory; (ii) a sensing assembly to detect any deviation of the belt from its central path on conveyor structure, the sensing assembly consisting of a transverse beam pivotally hinged on the plurality of equal length arms pivotably hinged from the support beam, plurality of telescopic arms pivotably hinged on either side of the transverse beam, and a plurality of adjustable guide rollers fixed at end of the telescopic arms; (iii) a plate having a special tapered pin fitted at its bottom, and a guide block fixed to the plate on side facing the sensing assembly; (iv) a tracking idler or plurality of tracking idlers mounted / bolted/fastened on the plate to keep the plate substantially perpendicular to belt travel direction; and (v) a connecting link mechanism / linkage to transmit movement of the guide rollers / guide block to the plate comprising a threaded pin with a freely rotatable ball bush. BRIEF DESCRIPTION OF INVENTION:

Fig. l illustrates an Isometric View of 3 D Belt Tracker Assembly with conveyor belt and stringer.

Fig.2 illustrates an Isometric View of 3 D Belt Tracker Assembly without conveyor belt and stringer.

Fig.3 illustrates front view of the Idler mount frame assembly showing the extension arm and the Idler mount plate arrangement.

Fig.4 illustrates side cross-sectional view of 3D Belt Tracking assembly showing the ball bush detail and the idler mount plate and inclined pin.

Fig.5 illustrates Tracker Arm Assembly showing the sensing rollers mounted on the extension plates with angular Position adjustment

Fig.6 illustrates front view of 3D Belt Tracking Assembly

Fig.7 illustrates Plan view of 3D Belt Tracking assembly.

Fig.8 illustrates idler mount plate assembly.

Fig.9A illustrates neutral position detail of the 3D Belt Tracking assembly.

Fig.9B & 9C show the tilting and swivel detail of the 3D Belt Tracking assembly.

DETAILED DESCRIPTION:

Accordingly, a 3-D belt tracking assembly to bring the mis-tracked conveyor belt back on track is disclosed in the present invention. The 3-D belt tracking assembly comprises a support frame assembly fixed across conveyor belt width to support conveyor belt consisting of a support beam having plurality of telescopic legs bolted/fastened onto a conveyor stringer, a sleeve passing through centre of the support beam, and a plurality of equal length arms are pivotally hinged from the support beam rotatable about their respective hinge thereby tracing an arc trajectory; a sensing assembly to detect any deviation of the belt from its central path on conveyor structure, the sensing assembly consisting of a transverse beam pivotally hinged on the plurality of equal length arms pivotably hinged from the support beam, plurality of telescopic arms pivotably hinged on either side of the transverse beam, and a plurality of adjustable guide rollers fixed at end of the telescopic arms; a plate having a special tapered pin fitted at its bottom, and a guide block fixed to said plate on side facing the sensing assembly; a tracking idler or plurality of tracking idlers mounted / bolted/fastened on the plate; and a connecting link mechanism / linkage to transmit movement of the guide rollers / guide block to the plate comprising a threaded pin with a freely rotatable ball bush. When the conveyor belt mis- tracks, guide rollers move towards mis-tracked belt direction, causing the ball bush to swivel and tilt the plate about said special pin, further causing the tracking idler to swivel and tilt, making the plate and the tracking idler to raise on the side of mis-tracked belt, thereby steering mis-tracked belt back to track.

In a preferred embodiment, guide rollers are fixed at the end of either of the telescopic arms extended to predetermined width. The telescopic arms are locked at a position using bolts passing through the transverse beams. A bracket is attached to center of the transverse beam. The guide rollers remain substantially aligned in the transverse direction while the telescopic arms trace an arc trajectory. A machined slot in the guide block accommodates the threaded pin with the freely rotatable ball bush thereby allowing the threaded pin to slide longitudinally in the machined slot. The link mechanism ensures that the transverse beam is alligned substantially perpendicular to the direction of the belt travel. The sensitivity of tilting action is adjusted by adjusting a taper of said special pin. The present invention can be best understood by referring to figures and illustrations explained in detail.

The 3 Dimensional belt tracking assembly which brings mistracked belt back on track comprises of a support frame assembly which is fixed across the belt width on the conveyor stringer frame (1).

Fig. 1 illustrates Isometric View of 3 D Belt Tracker Assembly with conveyor belt and stringer, it shows the general arrangement of the 3 D Belt Tracker in relation to the belt (24) and the direction of the belt movement which is given by the arrow (AA). Also the method of mounting on to the stringer is also shown.

Fig. 2 illustrates an Isometric View of 3 D Belt Tracker Assembly without conveyor belt and stringer, it also shows the general arrangement of the 3D tracker ; the possible displacement of the sensing assembly is shown by the arrow A and B . The actual direction of motion will be A or B depending on the direction of the belt displacement. The arrows B l and B2 shows that the plate and training idlers are raised at one end and lowered at the other end to impart a tilt. This action enhances the tracking action on the belt.

Referring to Fig. 3, the support frame assembly comprises of a support beam (2) with telescopic legs (6A & 6B) which can be extended to the required length by bolting using bolts (5A & 5 B) onto the conveyor stringer. A sleeve (3) passes through the centre of the support beam (2). The sleeve (3) is inclined to the vertical of the support beam such that the top side of the sleeve (3) leans towards the tail end of the conveyor.

Referring to Fig. 5, Fig. 6 & Fig.7, a sensing assembly consists of a transverse beam (12) with bushes (13A & 13B) which is pivotal ly supported using pins (23A & 23B) by two equal length arms (21 A & 2 I B) that are inturn pivotally hinged using pins (22A & 22B) & with bushes (4A & 4B) from the support beam (2). The equal length arms trace an arc trajectory (C 1 &C2) however the sensing assembly remains aligned substantially perpendicular to the direction of the conveyor movement. Two telescopic arms (15A, 15B) are pivotally hinged on either ends of the transverse beam (12). The two telescopic arms being pivotally hinged with pins (19A & 19B) are capable of rotating about the pins Axis X4 and X5 respectively. The telescopic arms can be locked at a desired trough position using bolts (20 A & 20B) that passes through the transverse beam. The telescopic arms have extendable members which can be moved to the desired position to suit the belt width and clamped using bolts (16A, 16C & 16B, 16D). Guide rollers are fixed at the distal end of the extendable members (17A & 17B). The sensing assembly is placed on the side of the support frame assembly which is towards the tail end of the belt. A bracket (14) is attached to the centre of the transverse beam.

Fig. 8 refers to idler mount plate assembly. A plate (7) with a special tapered pin is fitted on its bottom side is pivoted about the sleeve (3) that is fixed at the centre of the support beam. A guide block (9) is fixed to the plate on the side that faces the sensing assembly. The training idler (25) (Ref. Fig. l,) is mounted on the plate (7) such that it is substantially perpendicular to the belt travel direction. A connecting link mechanism comprising of a threaded pin (1 1) with a freely rotatable ball bush (10) which transmits the movements of the sensing assembly to the plate.

Referring to Fig. 4, the special pin (8) comprises of a top part which has bigger cross section than the internal diameter of the sleeve and has a tapered profile as shown in figure. The middle section fits into a sleeve (3) of the support beam (2). The inclination of the sleeve from the vertical to the support beam is the same angle as taper provided to the special pin. The lower part of the special pin (8) is threaded and bolted to prevent the plate from accidentally coming out but permits free rotation of the special pin. Between the pin and the sleeve, suitable bushes are provided for reducing friction and wear.

As a consequence of the sleeve being inclined and the pin being tapered, the plate rests substantially parallel to the plane of the support frame when the plate is neutral position (ie the belt is in the centre position and the training idler is substantially perpendicular to the belt travel direction).

When the plate is swiveled about the sleeves axis (X3) the above construction imparts a tilt to the plate.

The guide block (9) has a machined concave slot to accommodate the ball bush pin and allow it to slide longitudinally in the concave slot. There is a clamp at the end of the slot to stop the movement of the ball bush pin.

The ball bush pin comprises of the pin ( 1 1) which has a threaded end on top that is bolted on to the bracket (14) of the transverse beam of the sensing assembly and the other end has a freely rotatable ball bush that sits on the other end of the pin. The ball bush fits into the slot of the guide block and can slide longitudinally in the slot.

The ball bush arrangement allows the guide block to swivel and tilt about it and also compensates for the change in relative distance between the bracket and the guide block by sliding along the slot and also for the change in orientation of the plate with respect to the sensing assembly. Fig.9A illustrates neutral position of the 3D Belt Tracking assembly. It may be noted that the plate and consequently the training idler is parallel to the stinger which is illustrated by the distance between the base of the training idler and the stringer support being the same on either side which is shown as X.

Fig.9B and 9C shows the position of the 3D Belt Tracking when the belt is mistracked and the sensing assembly is pushed to the respective side to which the belt is mistracked. When the belt is mistracked towards the left side, when viewed from the tail end, the sensing guide rollers are moved to the left side which causes the plate and therefore the troughing idler to be tilted, this is illustrated in Fig 9B. It may be noted that the left side is raised and the right side is lowered. The same is illustrated by the distance distance between the base of the training idler and the stringer support being X+TH on the left side and X-TH on the right side.

When the belt is mistracked towards the right side, when viewed from the tail end, the sensing guide rollers are moved to the right side which causes the plate and therefore the troughing idler to be tilted which is illustrated in Fig 9 C. It may be noted that the right side is raised and the left side is lowered. The same is illustrated by the distance between the base of the trough idler and the stringer support being X+TH on the right side and X- TH on the left side. TH is tilting height.

Suitable bushes are provided in the entire hinged portion so as to reduce friction and wear.

The working of 3-D belt tracking assembly is as follows:

When the belt (24) is mis-tracked, it comes in contact with one of Guide roller (1 8A OR 18B), the entire sensing assembly, as shown in Fig.5, is forced to move in the mis-tracked direction. The sensing assembly being supported by two equal length structures (21 A & 2 IB) is kept substantially perpendicular to the belt direction and moves the guide rollers towards the mistracked direction. The movement of the sensing assembly and therefore the bracket (14) in the mistracked direction causes the ball bush arrangement to swivel the plate assembly about the special pin (8). The plate's special pin design ensures that the plate tilts as it swivels.

The ball bush arrangement due to the special ball bush arrangement is able to align and slide about the guide bush there by compensating for change in distance between the bracket and the plate's pivot due the tilt and swivel movement made in the plate assembly.

Since the tracking idler is mounted on the mount plate through bolting arrangement so the idler also swiveled and tilted. The construction ensures that the plate and tracking idler is raised on the side of the mistracked belt thus using the belt and material weight to guide the belt back to track. Thus the belt is steered back to track.

It should be noted that by increasing or decreasing the taper 8A of the special pin 8 and consequently the inclination of the central bush, the sensitivity of the tilting action can be increased or decreased. Also by increasing or decreasing the distance between the special pin (8) and threaded pin with freely rotatable ball bush (1 1 ) the sensitivity of the swiveling action can be decreased or increased. The equal length arms (21 A & 21 B) also need to suitably modified.

By giving suitable telescopic extensions for the arms (17A & 17B) and the bracket the sensitivity of the tracker can be changed.

Thus, the present invention provides a novel assembly to track the mis-tracked conveyor belt. The invention provides accordingly a 3-D belt tracking assembly that tracks by combining both swiveling, i.e. movement along the horizontal plane, and tilting, i.e. movement on vertical plane, of the tracking idlers (3Dimenional tracking). Also the perpendicular distance between the guide rollers in the transverse direction of the belt travel is kept substantially constant by means of the above described equal length arms and linkage mechanism. The two guide rollers move such that the distance when measured perpendicular to the belt travel is substantially equal. As a result the guide roller can be positioned very close to the belt and hence immediate response is possible when the belt mis-tracks.

While few possible designs modifications have been discussed above for attaining the desired swivel and tilt, the scope of the disclosure should not be limited to only the above illustrated designs.

It will be appreciated that a person skilled in the art may carry out modifications to the invention disclosed hereinabove without departing from the scope thereof. Hence, the particular embodiments described in detail herein are illustrative only and are not limiting to the scope of the invention, and which is to be given the full breadth of the appended claims and any all equivalents thereof.

Claims

We claim,

1. A 3-D belt tracking assembly to bring the mis-tracked conveyor belt back on track by combining both swivelling and tilting movements, comprising:

a support frame assembly fixed across conveyor belt width to support conveyor belt consisting of a support beam having plurality of telescopic legs bolted/fastened onto a conveyor stringer, and a sleeve passing through centre of said support beam, and a plurality of equal length arms are pivotally hinged from the support beam rotatable about their respective hinge thereby tracing an arc trajectory;

a sensing assembly to detect any deviation of the belt from its central path on conveyor structure, said sensing assembly consisting of a transverse beam pivotally hinged on the said plurality of equal length arms pivotably hinged from the support beam, plurality of telescopic arms pivotably hinged on either side of said transverse beam, and a plurality of adjustable guide rollers fixed at end of said telescopic arms;

a plate having a special tapered pin fitted at its bottom, and a guide block fixed to said plate on side facing said sensing assembly;

a tracking idler or plurality of tracking idlers mounted / bolted / fastened on said plate to keep said plate substantially perpendicular to belt travel direction; and a connecting link mechanism / linkage to transmit movement of said guide rollers / guide block to said plate comprising a threaded pin with a freely rotatable ball bush;

wherein said guide rollers move towards mis-tracked belt direction, causing said ball bush to swivel said plate about said special pin, , further causing the tracking idler to swivel and tilt, making the plate and the tracking idler to raise on the side of mis-tracked belt, thereby steering mis-tracked belt back to track.

2. The 3-D belt tracking assembly according to claim 1 ; wherein said sleeve is inclined to the vertical of the said support beam so that top side of said sleeve is towards tail end of the conveyor.

3. The 3-D belt tracking assembly according to claim 2; wherein said plate is rested substantially parallel to the plane of said support frame due to inclination of said sleeve when said plate is neutral position.

4. The 3-D belt tracking assembly according to claim 1 ; wherein said guide rollers are fixed at the end of either of said telescopic arms extended to predetermined width.

5. The 3-D belt tracking assembly according to claim 1 ; wherein said telescopic arms are locked at a position using bolts passing through said transverse beams.

6. The 3-D belt tracking assembly according to claim 1 ; Where in a bracket is attached to the centre of the transverse beam helps to transmit the movement of the sensing arm to the guide block of the idler mount plate through the threaded pin with freely rotatable ball bush which is bolted on to the bracket.

7. The 3-D belt tracking assembly according to claim 1 ; wherein said transverse beam and guide rollers remain aligned substantially perpendicularly to the direction of the belt movement while said equal length arms trace an arc trajectory.

8. The 3-D belt tracking assembly according to claim 1 ; wherein a machined slot is provided to said guide block to accommodate said threaded pin with said freely rotatable ball bush thereby allowing said threaded pin to slide longitudinally in said machined slot.

9. The 3-D belt tracking assembly according to claim 1 ; wherein said link mechanism restricts said sensing assembly to reamain alligned substantially perpendicular to the direction of the belt travel.

10. The 3-D belt tracking assembly according to claim 1 ; wherein sensitivity of tilting action is adjusted by adjusting a taper of said special pin.

1 1. The 3-D belt tracking assembly according to claim 1 ; wherein sensitivity of swiveling action is adjusted by changing the distance between said special pin below said plate and said threaded pin with freely rotatable ball bush.

12. The 3-D belt tracking assembly according to claim 1 ; wherein lengths of said equal length arms are to be suitably modified.