GB2164311A - Roller conveyors - Google Patents

Abstract

A roller conveyor is arranged for queueing of articles by a system of free wheels and clutches which are sensor-operated by the articles on the conveyor. Drive is transmitted from a common drive element to individual sets and groups of conveyor rollers by clutches operated by the sensors. Figure 1 shows a common transmission 76 connected by the clutch to the two transmissions 28 and 32 so as to connect the two adjacent sets, the rollers 10, 12, 14 in one set being looped by the linking transmission 24, and those in the other sets 16, 18, 20 being linked by the looping transmission 26. The clutch may alternatively be a driver clutch roller movable into contact with adjacent rollers, one from each set (see Fig 4). <IMAGE>

Description

SPECIFICATION Roller conveyors.

This invention relates to roller conveyors of the kind comprising a series of rollers which support and allow conveyance and storage of articles.

Prior Patent GB-1532522 describes an arrangement in which a whole series of parallel rollers in a common group are all connected by individual clutches, one clutch per roller, to a common drive chain.A sensor projects into the path of movement of articles on the conveyor and when contact by articles actuates all of the clutches of the group to disengage drive from these rollers. This arrangement is designed for a single direction of movement along a straight section of roller track and is relatively expensive to manufacture, and the object of the invention is to provide a simplified arrangement for like purposes that can also be reversed in direction and perform an accumulation function along both curved and straight sections of roller track.

According to the invention a roller conveyor comprises a plurality of rollers of which two adjacent ones, are connected to a common transmission by a single clutch under the control of a sensor projected into the path of movement of articles on the conveyor.

The term "set" used herein means a plurality of rollers connected by a linking transmission. The term "group" used herein means a plurality of sets occupying a track length which is approximately equivalent to the intended unit length of articles for which a conveyor is designed, or to the maximum expected length of such articles. By these means, a second article may be at rest upon a second half of a group whilst an article on the first half of the same group is driven away because its leading end rests on the second half of a preceding group of which the clutch is engaged for drive transmission.

Alternatively a free wheel device is interposed between the clutch and the transmission or between each roller and the transmission within a set or within a group and the effect of this is that the set or group is only positively driven by the drive means when the clutch is engaged, but the same set or group or each roller within the group or set can be driven by an article on the set or group or individual roller which is being displaced by other means (as hereinafter described) when the clutch is disengaged.

According to a feature of the invention, the clutch can comprise a shiftable intermediate roller positioned between two carrier rollers of different sets and large enough in diameter to connect them for drive transmission. This clutch - roller is engaged for drive transmission by a force, such as a pneumatic ram, applied to one end so that it pivots to connect the other end with the drive means, thereby transmitting driving force from the drive means to the carrier rollers. This arrangement can be used to drive tapered as well as parallel rollers.

By these means the invention can be employed along curved sections of roller track.

According to a feature of the invention the drive means is guided at intervals by grooved rollers, such as vee-pulleys, each with a continuous single or double sided groove in the outside edge. Along curved sections of the roller track the drive means is restrained within this groove by means of a second roller, other than the carrier roller, positioned so that the respective surfaces of the two rollers are in close enough proximity as to retain the drive means in the groove.

The sensors will normally be located between the sets of a group, and each sensor will be connected to the clutch of the next succeeding group, not to the group in which it is mounted. The result of this is that articles will be progressed along the conveyor with a space between successive articles, unless queueing or accumulation occurs, for example because of some independent barrier or obstacle.

According to another feature of the invention, the sensor can be made operational in either direction of movement of articles along one and the same conveyor, by making the sensor to rock clockwise or counter-clockwise about a pivot and providing a pair of microswitches either of which is operated according to the direction of rocking. In any case, an electrical circuit between the switch and the clutch is preferred to enable overriding control systems to be employed so that drive can be connected or disconnected independently of sensor actuation.

Presently preferred embodiments of the invention are more particularly described with reference to the accompanying drawings in which: Figure Z is an elevation of a group; Figure 2 is a sectional elevation taken on the line 2-2 of Figure 1; Figure 3 is a fragmentary sectional elevation on the line 3-3 of Figure 1; Figure 4 is an elevation of a group in a second embodiment; Figure 5 is a sectional elevation taken on the line 5-5 of Figure 4; and Figure 6 is a sectional elevation taken on the line 6-6 of Figure 4.

Referring to the drawings, the conveyor comprises the usual side frame elements which journal the rollers, and in this illustrative example a single group of rollers comprises two sets, namely the rollers 10, 12 and 14 equispaced in the one set and the rollers 16, 18, 20 likewise in the second set. As mentioned the rollers are journalled in the side frames 22 and each set is looped by a common coupling chain 24 for the first set and 26 for the second set. The first set is linked by a chain 28 to one clutch element 30 (Figure 2) whilst the second set is connected by chain 32 to a second clutch element 34. These clutch elements are associated with a third clutch element 36.A tie rod 38 extends through all three clutch elements and is connected to a pneumatic cylinder 40 so that when the cylinder is actuated, the elements 30, 34, 36 are urged into drive transmitting relationship one with the other, and when the cylinder is not so actuated, that is exhausted and/or possible spring returned, the pull on the rod 38 is released and the three elements are free for relative angular movement ("free wheeling"). The element 36 is connected to a drive motor, for example it may also be a chain sprocket connected to a further continuous roller chain extending along the line 76 Figure 1 and which serves to connect all of the groups together along the length of the conveyor, the chain looping a sprocket on the motor per se.It will be noted that this arrangement of simple friction clutch elements effectively provides a free wheel in that when the clutch elements are forced together, all can be driven by the same drive motor, but when the clutch is not actuated, any of the sets (half groups) can have the rollers rotated with the corresponding clutch element 30, 34 turning relative to the others.

Referring now to Figures 4-6, the conveyor here shown comprises the usual side frame elements which journal the rollers, and in this illustrative example a single group of rollers comprises four sets namely the rollers 47, 48, 49, 50 equispaced in two sets forming one half of the group and the rollers 51, 52, 53, 54 likewise the second half of the group.

Each set is looped by a common coupling belt 56 for the first set and 57 for the second set and 58 for the third set and 59 for the fourth set. Each set is connected together by a common intermediate clutch-roller 60 for the first two sets and 61 for the second two sets. Each intermediate clutch-roller also connects its respective sets with the drive means 66.

A pneumatic cylinder is anchored at one end, to the conveyor side frame, with the other end attached to one end of the clutch-roller axle 68 (Figure 5), 69 (Figure 6), with the other end of the axle located in a vertical groove in the opposite side frame to limit its movement to the vertical plane.

The cylinder is arranged to deliver thrust in the direction of the arrows, 67 in Figure 5, or 72 in Figure 6.

The clutch-roller 61 (Figure 5) or 71 (Figure 6) is urged into the drive transmitting position by actuating the pneumatic cylinder, which in turn pivots the clutch-roller on two adjacent carrier rollers thereby moving the end of the clutch-roller opposite to the pneumatic cylinder to connect with the drive means 66 (Figure 5), 73,(figure 6) and when the cylinder is not so actuated, that is exhausted and/or possibly spring returned, the clutch roller is released from the drive transmitting position. The drive element 66 (Figure 5), or 73 (Figure 6) serves to connect all of the groups together along the length of the conveyor, the belt looping a pulley on the motor per se.This arrangement of simple friction clutch elements effectively provides a free wheel in that when the clutch elements are forced together, all can be driven by the same drive motor, but when the clutch is not actuated, any of the sets can have the rollers rotated.

The sensor and probe element for one group may be located halfway along the length of the next adjacent group, that is pitched apart from the centre of the group by a distance about equal to the length of the group. In the illustrated form, the probe 55 (Figure 4), or 40, 42, 44 (Figures 1 and 3), comprises a hexagonal rod 40 (Figures 1 and 3) pivoted eccentrically upon the axis of mounting screws 42 at its ends, and carrying a pair of short small diameter rollers 44 on its upper face. A spring 77 is provided to locate the sensor in the erected position, as seen in Figure 3, in which the rollers 44 are located in the path of articles carried on the conveyor. The chain dot lines 44a, 44b show two alternate pivoted and displaced positions of the sensor, according to whether articles have been fed left to right or right to left in Figure 1.

Figure 3 illustrates the location of a microswitch assembly 46 which may be connected in series with a solenoid valve controlling the flow of pneumatic fluid to and from the cylinder 40: this enables the control to be effected remotely, for example from a programmer, or by the actual sensor position.

Assuming that an article of the same length as the complete group is moved along the conveyor by driven rollers, it will be appreciated that the article will displace the probe disconnecting drive to the illustrated group whilst the article is being supported by and possibly conveyed by the preceding group. However, if the trailing end of the article passes that probe, the illustrated group will be reenergised and so on. Single articles can be fed along the complete conveyor without drive being effectively interrupted, as long as there is adequate gap between each article and the next. If the gap becomes inadequate for any reason, the next following article effectively disconnects the drive.

This means that articles will accumulate or queue until one article is removed and then normal flow will be re-established.

Claims (14)

1. A roller conveyor comprising a plurality of carrier rollers of which two adjacent ones are connected to a common transmission by a single clutch under the control of a sensor projected into the path of movement of articles on the conveyor.

2. A conveyor as claimed in Claim 1 wherein said adjacent rollers each form part of a (different) set of rollers and all of the rollers in each set are linked by a transmission common to that set.

3. A conveyor as claimed in Claim 2 wherein the said two sets comprise a group arranged to occupy a track length which is approximately equivalent to the intended unit length of articles for which the conveyor is designed.

4. A conveyor as claimed in Claim 2 and Claim 3 wherein additional sets disposed further along the length of the conveyor form part of the same group and are arranged to be driven from the same transmission under the control of the same sensor.

5. A conveyor as claimed in any preceding claim wherein a free-wheel drive is interposed between the clutch and the transmission.

6. A conveyor as claimed in any of Claims 1 to 4 wherein a free-wheel device is interposed be tween each carrier roller and any transmission within the set or group of which the roller forms a part.

7. A conveyor as claimed in any preceding claim wherein the clutch comprises a shiftable intermediate roller positioned between two of said plurality of carrier rollers and large enough in diameter to connect them to the drive transmission.

8. A conveyor as claimed in Claim 7 wherein said intermediate roller is pivoted for displacement between clutch engaged and clutch disengaged positions.

9. A conveyor as claimed in Claim 8 wherein the pivot is the drive means.

10. A conveyor as claimed in Claim 8 wherein the pivot is the two adjacent carrier rollers.

11. A conveyor as claimed in any preceding claim wherein the clutch comprises a shiftable carrier roller or rollers pivoted for displacement between clutch engaged and clutch disengaged positions.

12. A conveyor as claimed in Claim 11 wherein the shiftable carrier roller or rollers is/are pivoted on an intermediate roller.

13. A roller conveyor substantially as described with reference to Figures 1 to 3 of the accompanying drawings.

14. A roller conveyor substantially as described with reference to Figures 4 to 6 of the accompanying drawings.