GB1560752A

GB1560752A - Conveyors

Info

Publication number: GB1560752A
Application number: GB967076A
Authority: GB
Original assignee: ICE Ltd
Current assignee: ICE Ltd
Priority date: 1977-05-16
Filing date: 1977-05-16
Publication date: 1980-02-06

Description

(54) CONVEYORS (71) We, I.C.E. (MATERIALS HANDLING) LIMITED, aBritish Company, of 175 Sandwell Road, Birmingham, West Midlands, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to conveyors.

In particular, the invention is concerned with a conveyor of the kind, hereinafter referred to as the kind specified, comprising support means, load-advancing means constituted by a set of load-engaging members and operating means for moving the members in a manner such that they act in succession on a load to advance it stepwise along the conveyor, each member being moved in a continuous path firstly upwardly from a lowered position in which a load-engaging face thereof is below a load-supporting face of the support means, to a raised position in which its said face is above the said face of the support means whereby it engages a load supported by the latter, then longitudinally of the conveyor to advance the load, then downwardly back to its lowered position thereby to disengage from the load, and finally back to its original position.

The support means may comprise either a fixed track or a second set of load-engaging members operable in the same manner as, and in correlation with the first set.

The invention is primarily, but not exclusively, applicable to walking beam conveyors wherein the load-engaging members are constituted by beams extending longitudinally of the conveyor, each beam being operable to lift a load supported by the support means as it is moved from its lowered position to its raised position, to advance the load along the conveyor and then to deposit the load on the support means as it is returned to its lowered position.

In many applications of conveyors of the kind specified, it is necessary to reverse the direction of feed of loads along the conveyor. Various forms of operating means having provision for reversal of the direction of feed have previously been proposed but they have the disadvantage that they are very complicated and involve considerable modifications of their manner of operation to effect such reversal.

The object of the present invention is to provide an improved form of conveyor of the kind specified in which, in particular, its direction of feed can be reversed simply and quickly.

According to the invention, there is provided a conveyor of the kind specified wherein the operating means of each load-engaging member comprises first means for reciprocating the member longitudinally of the conveyor so that in each cycle of movement of the member it performs two stokes in opposite directions, second means arranged to act on the member, on reciprocation of the latter, to raise the member relative to said second means at or adjacent to the beginning of each stroke thereof and to lower the member relative to said means at or adjacent to the end of each stroke, third means for raising said second means on one stroke of each cycle so that said second means is effective on said stroke to raise the member above the support means whereby, in use, the member engages a load supported by the support means and advances it along the conveyor, and for lowering said second means on the other stroke of each cycle so that said second means is not effective on said stroke to raise the member above the support means whereby in use the member does not engage a load supported by the support means, and control means operable to determine selectively the strokes of each cycle on which the said second means is raised and lowered whereby the direction of feed of the conveyor can be changed.

As mentioned above, the invention is primarily applicable to walking beam conveyors. For convenience the following description will be confirmed to this application of the invention, but it is to be understood that there is no limitation in this regard since the invention is also applicable to other types of conveyor of the kind specified. Moreover the invention has been devised primarily in connection with a walking beam conveyor in which the support means comprises a fixed track, for example two spaced parallel rails with the beams disposed between them in end-to-end relationship, but again it is to be understood that thereis no limitation in this regard.

The idea of the invention, in a walking beam conveyor, is that the said second means of each beam acts to raise the beam for each stroke of its cycle of movment and to lower the beam at the end of each stroke. By itself this would result in the beam being raised above the support means on both strokes of the beam, but the said third means acts to override the effect of the second means on a selected one of the strokes determined by the control means, so that the beam is maintained below the support means and therefore does not pick up a load on this stroke, the second means being effective to raise the beam above the support means to advance a load along the conveyor only on the other stroke.

The direction of feed of the conveyor is therefore determined by which of the two strokes of each cycle of movment of the beam has the beam raised above the support means so that it picks up a load from the latter, advances it along the conveyor and then deposits it on the support means, and which of the two strokes is effective merely to return the beam to its origial position without it being raised above the support means. The idea of the invention is that the roles of the two strokes of each cycle of movement of the beam can be reversed to reverse the direction of feed of the conveyor simply by operating the control means to change the stroke of the beam over whch it is maintained in a lowered position.

The said second means of each load-engaging member preferably comprises cam means. In a preferred embodiment these means comprises a cam disposed beneath the member and a cam follower provided on the member so as to be movable with the member, on reciprocation of the latter, longitudinally relatively to the cam, the cam follower running on a cam face of the cam on such movement.

In an alternative arrangement the cam may be provided on the beam with the cam follower.mounted beneath it.

The said third means preferably comprises at least one link pivotally connected to the said second means, i.e.

the cam in the preferred embodiment, and swingable about a fixed pivot between a first position at an angle to the vertical in which the second means has been raised by the link, and a second position at a greater angle to the vertical in which the second means has been lowered by the link, means being provided for moving the link to said first position for a selected one of the two strokes of each cycle of movement of the member determined by the control means and for moving the link to said second position for the other stroke determined by the control means.

Preferably the said second means, i.e. the cam, is supported by at least two said links so that movement of the said means in one or the other longitudinal direction causes pivoting of the links about their fixed pivots from the first to the second position or vice versa, and abutments are provided on the second means and arranged to be engaged by a part of the member, for example the cam follower in the preferred embodiment, when the latter reaches the end of each stroke, whereby the member pushes the second means longitudinally and thereby moves the links from their first position to their second position, or vice versa as the case may be.

The control means may comprise stops arranged for engagement by the links to limit their movement to said first and second positions, the dispositions of the stops being changeable to change the direction of feed of the conveyor, or stops arranged for engagement by the said second means on a selected one of the two strokes of each cycle to determine the lowered position of the second means, and by depending projections on the said second means on the other of said strokes to determine the raised position of the second means, the stops being movable to change the direction of feed of the conveyor.

As will be appreciated in both cases it is solely the dispositions of the stops which determine which of the two strokes of each cycle of movement of the member is effective and which of the two strokes is ineffective. The main advantage of the invention is that the direction of feed of the conveyor can be reversed simply by changing the dispositions of the stops.

The invention will now be described by way of exampe with reference to the accompanying drawings, in which: FIGURES 1A to 1E show diagrammatically successive stages in the cycle of operation of one form of walking beam conveyor embodying the invention.

FIGURES 2A and 2B show, respectively and in side elevation, the left and the right hand parts of a specific constructional example of a walking beam conveyor of the form shown in Figures 1A to 1E, and Figure 3 is a cross section through the conveyor of Figures 2A and 2B.

Referring to Figures 1A to 1E the conveyor comprises two spaced parallel horizontal support rails 10 and a set of horizontal load-engaging beams, one of which is shown at 11, arranged end-to-end and disposed between the rails. The rails are formed by two fixed vertical plates which enclose the beams at the sides thereof and each beam comprises two spaced parallel longitudinal members inter connected by two spaced transverse axles.

The two axles of each beam carry respectively two rollers 12 which constitute cam followers and rest on two cam faces 13 of a cam member 14. Each cam face 13 comprises a horizontal flat section 15 merging at each end thereof into a down wardly curved section 16 which in turn merges into an upwardly extending curved abutment section 17.

The cam member 14 of each beam is supported by two parallel links 18 each of which is pivotally connected at its upper end to the cam member and at its lower end to the side plates forming the rails 10.

Each link has two associated stops 19, 20 mounted on the side plates and arranged to limit the extent of swinging movment of the link in opposite directions about its lower pivot.

Means (not shown) are provided for applying a reciprocating linear movement to each beam longitudinally thereof.

Operation of the conveyor is as follows, starting with the conveyor in the position shown in Figure 1 with an article A supported by the rails 10 above the beam 11, the upper article-engaging face of the beam below the upper article-supporting faces of the rails, the rollers 12 resting in the downwardly curved sections 16 at the left-hand ends of the cam faces 13 (as viewed in the drawings) so that the beam is in a lowered position relative to the cam member, and the links 18 abutting the stops 19 which are arranged so that the limbs are disposed in positions at a first, smaller angle to the vertical and the cam member is therefore in a raised position.

The reciprocating means is operated to move the beam 11 to the right and as a result the rollers 12 run along the cam faces 13 out of the downwardly curved sections 16 on to the higher flat sections 15 so that the beam moves to a raised position relative to the cam member to lift the article A off the rails 10 and to carry it along the conveyor, as shown in Figure 1B.

The rollers 12 then run downwardly into the downwardly curved sections 16 at the right-hand ends of the cam faces 13 so that the beam is returned to its lowered position relative to the cam member at the end of this first stroke of the beam and thereby deposits the article A on the rails 10.

Also at the end of the first stroke of the beam the rollers 12 come up against the abutment sections 17 of the cam faces 13 with the result that the cam member 14 is pushed to the right, under the continued action of the reciprocating means on the beam, and the links 18 are pivoted about their lower pivots until they abut the stops 20, as shown in Figure 1C. The links are arranged so that when they swing between the stops 19, 20, the beam does not rise above the rails and the article A is therefore not disturbed.

The stops 20 are arranged to limit the movement of the links 18 to positions at a second, greater angle to the vertical so that the cam member 14 is moved to a lowered position and with it the beam 11 is moved to a position below its aforesaid lowered position.

The reciprocating means is then operated to reverse the direction of linear movement of the beam. The beam is therefore moved to the left, as shown in Figure 1D, its rollers 12 running out of the downwardly curved sections 16 of the cam faces 13 up onto and along the flat sections 15 and then downwardly into the downwardly curved sections 16 at the other ends of the cam faces. Throughout this second stroke of the beam it remains below the upper article-supporting faces of the rails 10 in spite of it being lifted by the cam faces, because the member cam has been moved to a lowered position.

When the rollers 12 abut the left hand abutment sections 17 of the cam faces, continued movement of the beam to the left under the action of the reciprocating means pushes the cam member 14 to the left and thereby causes the links 18 to pivot about their lower pivots back into engagement with the stops 19, as shown in dotted lines at 18' in Figure 1E. As a result, the cam member is returned to its raised position as shown in dotted Ines at 14' in Figure 1E, and the beam is returned to its aforesaid lowered position.

The conveyor is thus returned to the position shown in Figure 1 ready for its next operating cycle.

As the beam moves to the left, the next adjacent beam of the conveyor (not shown) likewise moves to the left to a position beneath the deposited article A so that at the beginning of the next operating cycle of said next beam it will lift the article off the rails and advance it along the conveyor to a positioll where its conveyance will be taken over by the next succeeding beam, and so on.

To reverse the direction of feed of articles along the conveyor, it is necessary merely to move the stops 19, 20 to the positions shown in dotted lines at 19', 20' in Figure 1. This has the effect of causing the cam member to be lowered at the end of leftwards movement of the beam so that when the beam moves to the left it remains beneath the upper faces of the rails 10, the cam member being raised again at the end of rightwards movement of the beam so that it will then be effective to advance an article picked up thereby as it moves to the left.

The reciprocating means may be of any one of a number of forms.

In one form the reciprocating means comprises an endless chain running around two sprockets and connected to the beam so that movement of the chain alternately in one direction and then the opposite direction imparts a reciprocating linear movement to the beam. One of the sprockets is driven by a suitably geared electric motor and the chain has a trip device arranged to actuate a switch at the end of each stroke of the beam thereby to reverse the direction of the motor.

In another form, the reciprocating means comprises a cable passing around a number of pulleys and connected at its ends to the beam so that movement of the cable in opposite directions reciprocates the beam.

The cable is connected to the piston of a double acting pneumatic piston and cylinder unit having variable outlet restrictors to enable the speed of reciprocation of the beam to be varied as required.

In another form, the reciprocating means simply comprises a double acting pneumatic piston and cylinder unit the piston of which is connected directly to the beam so that reciprocation thereof within the cylinder causes reciprocation of the beam. The unit is provided with variable outlet restrictors as in the previous form.

In another form the reciprocating means comprises a chain running around two sprockets and connected to the beam so that movement of the chain in two opposite directions reciprocates the beam. One of the sprockets is driven to effect this movement by a pinion engaged with a rack which is reciprocable by means of a double acting pneumatic piston and cylinder unit.

In yet another form the reciprocating means comprises a linear electric motor acting directly on the beam.

In a further form the reciprocating means comprises a geared electric motor driving a crank shaft which is connected to the beam by a connecting rod.

In those forms incorporating a pneumatic cylinder, this cylinder may be replaced by a hydraulic cylinder powered by a manually operated or motorised hydraulic pump.

Articles for feeding by the conveyor may be placed in succession on the support rails either by hand or by automatic delivery means.

The cam member of each beam may be formed in sections so that one or more sections can be replaced by a differently shaped section or sections ro produce a different motion of the beam, i.e. to change the distance through which each article is advanced by the beam and hence the spacing of the articles being conveyed along the conveyor, the height to which each article is lifted, the dwell time of each article on the rails, or any required combination of these. The speed of the conveyor can be varied by varying the speed of the reciprocating means.

The beams of the conveyor may be operated in synchronism or out of phase. In the latter case, the beams produce a ripple effect,'this reducing the power requirement of the conveyor since these sections of the cams which lift the beams do not act simultaneously but at different times.

Instead of the stops 19, 20, acting on the links 18 in the example illustrated in the drawings, stops may be provided for engagement by the cam member 14, it only being the disposition of the stops which is required to be changed to reverse the feed direction of the conveyor. In any event each two stops 19, 20 may be replaced by a single slidable stop member which is movable between two different positions.

Other forms of rolling bodies or even sliding bodies may be used in place of the rollers 12 for engagement with the cam.

Although the beam operating means shown in the drawings has been described applied to a conveyor having a fixed support track, it may also be applied to a conveyor in which articles are conveyed wholly by means of walking beams.

The conveyor may convey articles alone, for example freight containers, or article carriers, for example pallets. It may be an overhead conveyor having underslung article carriers extending downwardly from the conveyor. The conveyor may form part of a live storage system or it may be an accummulator conveyor, the beams carrying transverse rollers for supporting the articles to provide an idler track.

The beams may be provided with longitudinal rollers to enable articles to be discharged from them laterally of the conveyor.

The fixed track may incorporate a weighing machine for weighing the articles.

In another form conveyor provided by the invention, the load-engaging members may each be arranged, on its operative stroke when in its raised position, to engage a load so as to push it along a fixed track constituting the support means. In yet another form of conveyor provided by the invention the loadengaging members may each have a roller (or other rolling body) arranged, when the member is moved to its raised position, to engage the underside of a load so that, on the subsequent operative stroke of the member, the roller not only advances the load through a distance equal to the length of the stroke but also turns in contact with the underside of the load to advance the latter relative to the turning axis of the roller whereby the load is moved an additional distance on said stroke.This may be achieved by modifying the conveyor shown in the drawings to make the rollers 12 of a larger diameter so that, when the beam is moved to its raised position for an operative stroke, the rollers project upwardly above the load-supporting faces of the rails whereby it is the rollers which pick up a load, the load being advanced a distance equal to twice the length of the stroke. In this case, the beam itself will be made less deep and may in fact merely comprise a longitudinal member connecting the axles of the rollers, so that it is not at any time raised above the rails.

Figures 2A, 2B and 3 show a specific constructional example of a walking beam conveyor which operates according to the principle described with reference to Figures 1A to 1E. The same reference numerals are used to designate like parts.

In this conveyor the rails 10 are formed by two fixed vertical plates 21 having upper outwardly extending flanges 22 and lower inwardly extending flanges 23 which in turn have upstanding flanges 24. Each beam 11 is in the form of a box-like carriage having a platform 25 with depending side flanges 26 and, spaced inwardly from the latter, two further flanges 27. Each adjacent two flanges 26, 27 have three longitudinally spaced transverse axles 28 extending between them, and these axles carry rollers 12a, 12b and 12c.

The three rollers 12a, 12b and 12c at each side of the beam rest on a track defined by the lower limb of an L-section cam member 29, this limb having three longitudinally spaced cam faces 13 for co-operation, respectively, with the three rollers. The track therefore comprises horizontal flat portions between the cam faces which each comprises two curved end portions joined by a horizontal flat portion. The two L-section members 29 are connected together to form a cam member 14 by two transverse angle section members 30 adjacent the respective ends of the cam member.

The cam member 14 is supported by two pairs of parallel links 18 adjacent the respective ends of the member, the links of each pair being disposed at opposite sides of the member.

The two links 18 of each pair are pivotally connected at their support ends to a common bar 31 the ends of which are secured by grub screws in two mountings 32 secured to the vertical limbs of the respective L-section members of the cam member 14. Washers 33 are interposed between the said limbs and the limbs. The lower ends of the limbs 18 of each pair are likewise pivotally connected to a common bar 34 the ends of which are secured by grub screws in mountings 35 secured to the upstanding flanges 24 of the support rails 10.

The lower horizontal limbs of the L-section members 29 of the cam member 14 each has at intervals along its length a number of blocks 36 arranged to cooperate with a corresponding number of stops 37 carried by an elongate control member 38 which is adjustable longitudinally between two positions by hydraulic or pneumatic means or, as shown, by handles 39 at its ends. The direction of feed or the conveyor can be changed simply by moving the control member 38 from one position to another.

The means for reciprocating the beam comprises a hydraulic piston and cylinder unit (not shown) the piston of which is connected to a cross bar 40 carried by two depending lugs 41 attached to the underside of the platform 25 of the carriage.

The conveyor operates generally in the same way as the conveyor shown in Figures 1A to 1E. As the reciprocating means is operated to effect one stroke of the beam with the blocks 36 resting on the stops 37, the cams 13 will lift the beam to cause it to engage and advance an article. Towards the end of the stroke the beam will engage the relevant end of the cam member 14 and this causes the cam member to be swung about the links 18 through 600. The blocks 36 are thereby disengaged from the stops 37 and this permits the cam member to swing under gravity through a further 150 to a lower position. As a result, on the return stroke of the beam and as the cams 13 act on it, the beam is not lifted above the rails 10.

Towards the end of this stroke the beam engages the relevant end of the cam member and swings it back to a position in which the blocks 36 rest on the stops 37. If the control member 38 is adjusted, the blocks 36 rest on the stops 37 throughout the second stroke and not throughout the first stroke, so that the direction of feed is reversed.

WHAT WE CLAIM IS: 1. A conveyor of the kind specified wherein the operating means of each loadengaging member comprises first means for reciprocating the member longitudinally of the conveyor so that in each cycle of movement of the member it performs two strokes in opposite directions, second means arranged to act on the member, on reciprocation of the latter, to raise the member relative to said second means at or adjacent to the beginning of each stroke thereof to lower the member relative to said second means at or adjacent to the end of each stroke, third means for raising said second means on one stroke of each cycle so that said second means is effective on said stroke to raise the member above the support means whereby, in use, the member engages a load supported by the support means and advances it along the conveyor, and for lowering said second means on the other stroke of each cycle so that said second means is not effective on said stroke to raise the member above the support means whereby in use, the member does not engage to a load supported by the support means, and control means operable to determine selectively the strokes of each cycle on which said second means is raised and lowered whereby the direction of feed of the conveyor can be changed.

2. A conveyor as claimed in Claim 1 which is of the walking beam type wherein the load-engaging members are constituted by means extending longitudinally of the conveyor.

3. A conveyor as claimed in Claim 1 or Claim 2 wherein the support means comprises a fixed track.

4. A conveyor as claimed in Claim 3 when dependent on Claim 2 wherein the fixed track comprises two spaced parallel rails with the beam disposed between them in end-to-end-relationship.

5. A conveyor as claimed in any one of the preceding claims, wherein the said second means of each load-engaging member comprises cam means.

6. A conveyor as claimed in Claim 5 wherein the cam means of each load-engaging member comprises a cam disposed beneath the member and a cam follower provided on the member so as to be movable with the member, on reciprocation of the latter, longitudinally relatively to the cam, the cam follower running on a cam face of the cam on such movement.

7. A conveyor as claimed in any one of the preceding claims wherein the said third means comprises at least one link pivotally connected to the said second means and swingable about a fixed pivot between a first position at an angle to the vertical in which the second means has been raised by the link, and a second position at a greater angle to the vertical in which the second means has been lowered by the link, means being provided for moving the link to said first position for a selected one of the two strokes of each cycle of movement of the member determined by the control means and for moving the link to said second position for the other stroke determined by the control means.

8. A conveyor as claimed in Claim 7 wherein the said second means of each load-engaging member is supported by at least two said links so that movement of the said means in one or the other longitudinal direction causes pivoting of the links about their fixed pivots from the first to the second position or vice versa, and abutments are provided on the second means and arranged to be engaged by a part of the member when the latter reaches the end of each stroke, whereby the member pushes the second means longitudinally and thereby moves the links from their first position to their second position, or vice versa as the case may be.

9. A conveyor as claimed in Claim 8 when dependent on Claim 6 wherein the abutments comprise parts of the cam face of the cam and the cam follower constitutes the said part of the member for engagement with said abutments.

10. A conveyor as claimed in Claim 8 or 9 wherein the control means comprises stops arranged for engagement by the links to limit their movement to said first and second positions, the dispositions of the stop being changeable to change the direction of feed of the conveyor.

11. A conveyor as claimed in Claim 8 or Claim 9 wherein the control means comprises stops arranged for engagement by the said second means on a selected one of the two strokes of each cycle to determine the lowered position of the second means, and by depending projections on the said second means on the other of said strokes to determine the raised positioh of the second means, the stops being movable to change the direction of feed of the conveyor.

12. A conveyor operable substantially as herein described with reference to and as illustrated in Figures 1A to - lE of the accompanying drawings.

13. A conveyor substantially as herein described with reference to and as illustrated in Figures 2A, 2B and 3 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. and not throughout the first stroke, so that the direction of feed is reversed. WHAT WE CLAIM IS:

1. A conveyor of the kind specified wherein the operating means of each loadengaging member comprises first means for reciprocating the member longitudinally of the conveyor so that in each cycle of movement of the member it performs two strokes in opposite directions, second means arranged to act on the member, on reciprocation of the latter, to raise the member relative to said second means at or adjacent to the beginning of each stroke thereof to lower the member relative to said second means at or adjacent to the end of each stroke, third means for raising said second means on one stroke of each cycle so that said second means is effective on said stroke to raise the member above the support means whereby, in use, the member engages a load supported by the support means and advances it along the conveyor, and for lowering said second means on the other stroke of each cycle so that said second means is not effective on said stroke to raise the member above the support means whereby in use, the member does not engage to a load supported by the support means, and control means operable to determine selectively the strokes of each cycle on which said second means is raised and lowered whereby the direction of feed of the conveyor can be changed.