IES20070455A2 - Apparatus for stacking articles - Google Patents

Abstract

An apparatus for stacking articles comprises a loading station 12 for receiving successive articles to be stacked. A conveyor 14 removes the articles successively from the loading station, the removed articles being substantially equally spaced along the conveyor and the conveyor being driven to move intermittently by in each case a distance substantially equal to the inter-article spacing. A device 16 simultaneous picks a plurality of adjacent articles from the conveyor and transfers them to a like plurality of piles 36. <Figure 1>

Description

This invention relates to an apparatus for stacking articles.

According to the present invention there is provided an apparatus for stacking articles, comprising loading means for feeding articles successively to a loading station, a conveyor for removing the articles successively from the loading station, the removed articles being substantially equally spaced along the conveyor and the conveyor being driven to move intermittently by in each case a distance substantially equal to the inter-article spacing, and a device for simultaneously picking a plurality of adjacent articles from the conveyor and transferring them to a like plurality of piles.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of an apparatus according to the embodiment.

Figure 2 is a plan view of the apparatus of Figure 1 omitting the transfer mechanism.

Figure 3 is an enlarged side view of the indexing conveyor forming part of the apparatus of Figure 1. mechanism.

Figures 4 illustrates the operation of the transfer iht g.fefe)gte& srjor·, 6bse> ftTfeA The embodiment shows an apparatus for stacking elongated, open-ended steel sections 10 having a generally troughshaped cross-section. The apparatus comprises four main components: a loading station 12, an indexing conveyor 14, a transfer device 16 and an offload conveyor 18. A control unit 11 controls and synchronises the operation of these components.

At the loading station 12 the inverted sections 10 are fed by an accelerator conveyor belt 24, Figure 2, successively onto a stationary table 20 located over one end of the indexing conveyor 14 (the table is not shown in Figure 2). Each section 10 is slid onto the table 20 by movement along its own longitudinal axis normal to the direction of movement of the indexing conveyor 14. The direction of sliding each section 10 onto the table 20 is indicated by the arrow A in Figure 2 and the direction of movement of the conveyor 14 by the arrows B.

The table 20 has a stop plate 22 whose position relative to the width of the conveyor 14 is adjustable between 22' for short steel sections 10' and 22'' for long steel sections 10'' and to any point in between for intermediate length sections (despite both short and long sections 10', 10'' being shown together on Figure 2 for purposes of explanation, only one length of steel section will be handled at a time). If desired the stop plate 22 could be adjusted further to the right, as seen in Figure 2, for even longer section lengths. When the leading end 100 of a section 10 meets the stop plate 22 that section is properly positioned on the table for transfer by the indexing conveyor 14. «Ό704 55 The conveyor 14 comprises three laterally spaced endless chains 26 which are aligned with one another and synchronised for intermittent movement in a manner to be described. When a steel section 10 is properly positioned on the table 20 it will span either two chains (section 10') or three chains (section 10''), according to its length. Each chain 26 has a set of outwardly extending catches, in the form of pegs 28, which are arranged at equal intervals along the chain. Each peg 28 on a chain 26 is laterally aligned with a respective peg on each of the other chains so that the pegs are aligned in triplets across the width of the conveyor.

When the leading end of a steel section 10 meets the stop plate 22 a proximity sensor (not shown) sends a signal to the control unit 11 which initiates an indexing movement of the conveyor 14. This movement consists of a single movement of the conveyor chains 26, in the direction of the arrow C in Figure 3, by a distance equal to the distance between adjacent pegs 28, after which the conveyor stops. During such movement one of the pegs 28 on each chain spanned by the section 10 currently on the table 20 rotates up into contact with the inside front edge of the section 10 (the table being suitably slotted to allow such rotation), entrains that section, and removes it from the table 20 onto fixed rails 30 which extend along and just above the chains 26. The indexing movement therefore moves the section 10 from position 1 in Figure 3, i.e. on the table 20, to position 2 which is at a pre-determined position along the conveyor 14 from the table 20. Subsequent indexing movements, each initiated by a respective steel section 10 engaging the stop plate 22, slides each section 10 currently on the rails 30 one inter-peg distance further away from the £07 04 table 20 while simultaneously moving the section 10 on the table at position 1 into the second position 2.

A counter in the control unit 11 is incremented each time the conveyor 14 makes an indexing movement. Each time four such movements have been counted (five when the machine is initially started up), i.e. when all four positions 3-6 of the conveyor are occupied by a respective section 10, the control unit 11 activates the transfer device 30.

The transfer device 16 comprises a horizontally movable carriage 32 having four vertically movable electromagnetic heads 34. As seen in Figure 4, when the device 16 is activated the heads 34, initially held in a raised position over the respective conveyor positions 3-6, are lowered onto the sections 10 in those positions and then actuated to magnetically grip the sections 10. The heads 34 are now lifted and the carriage 32 moves horizontally until the four sections 10 held by the heads are over respective ones of four stacked piles 36 of sections (Figure 1) on the offload conveyor 18. Now the heads 34 are lowered so that the sections 10 held by the heads are lowered into the respective piles 36, whereupon the heads 34 are de-energised to release the sections.

The heads are now raised and the carriage 32 returns to its initial position over the conveyor 14. Clearly, loading of sections 10 onto the table 20 and indexing of the conveyor 14 is halted at least while the heads 34 are removing the sections 10 from the conveyor 14.

When four stacks of fifty sections 10 (a batch) have accumulated on the offload conveyor 18, the control unit 11 activates the conveyor 18 to provide space for te0704555 receiving the next batch. Once two batches have accumulated on the conveyor with a third being accumulated, the control unit activates a signal or an alarm to indicate that the batches need to be strapped and off-loaded - usually by a forklift. This means that a forklift operator need only attend the stacking station every hour or so to unload two or three batches of profiles.

The advantage of the embodiment is that pegs 28 ensure reliable spacing and alignment of the steel sections 10 when picked up by the transfer device 16, so ensuring the sections will be reliably stacked. If a conventional conveyor belt were used, this spacing would not be guaranteed.

The invention is not limited to the embodiments described herein which may be modified or varied without departing from the scope of the invention.

Claims (5)

Claims

1. An apparatus for stacking articles, comprising loading means for feeding articles successively to a loading station, a conveyor for removing the articles successively from the loading station, the removed articles being substantially equally spaced along the conveyor and the conveyor being driven to move intermittently by in each case a distance substantially equal to the inter-article spacing, and a device for simultaneously picking a plurality of adjacent articles from the conveyor and transferring them to a like plurality of piles.

2. An apparatus as claimed in claim 1, wherein the conveyor is an endless conveyor having a set of catches arranged at substantially equal intervals along its length, each catch for entraining a respective article at, and removing the article from, the loading station during movement of the conveyor.

3. An apparatus as claimed in claim 2, wherein the loading station comprises a support with a gap to allow each catch to rotate up into contact with an article resting on the support during movement of the conveyor.

4. An apparatus as claimed in claim 1, 2 or 3, wherein the articles are elongated and fed along their own axes to the loading station in a direction substantially normal to the direction of movement of the conveyor.

5. An apparatus as claimed in claim 4, wherein the conveyor comprises at least two laterally spaced sets of Ο <55 catches, each catch in one set being aligned with a respective catch in the other set.