BOARD TREATMENT APPARATUS

Abstract: Board treatment apparatus is for separating contiguous blanks one from the next in a common feed path and comprises a pair of acceleration rolls 20 22 to grip and feed the first of a pair of adjacent contiguous blanks along the feed path 12 whilst a second such blank is gripped by feed rolls 14 16 running at a lower surface speed. The feed rolls 14 16 are spaced from the accelerator rolls 20 22 by a distance which is at least substantially equal to the length of a single blank and essentially less than twice the length of a single blank, so that the feed rolls 14 16 on the one hand and the accelerator rolls 20 22 on the other hand never engage the same blank and only ever engage immediately adjacent blanks. Means are provided for varyin g the adjustment including a sprocket 48 to move subframe 18 carrying the accelerator rolls relative to a main frame 50 carrying the feed rolls, and wires 56 bridging the gap between the two so as to support the blanks in the feed path.

Description: This invention relates to board treatment apparatus for use in the production of discrete separated blanks out of larger blanks or from web material. This is done by cutting substantially through the board around the perimeter of the required blanks, so as to separate the blanks from the remainder or scrap. It is conventional to make the cuts incomplete or discontinuous so as to retain a connection, whilst the original blank or web proceeds through the treatment apparatus and only effect the separation at the end of the treatment. Various kinds of apparatus are known for separating the scrap from the blanks, but the present invention is concerned with a different problem: that of separating contiguous blanks one from the next. The connected blanks may be arranged successively along the feed direction, that is to say two or more blanks may have been created in succession out of the original blank or from a continuous web, and possibly also there may be two or more blanks laterally of the feed direction. The connections between these continuous blanks are not disturbed by the scrap removal apparatus and it is the object of the present invention to separate such continuous blanks wholly and completely from one another. According to the invention, apparatus for board treatment comprises a feed roll pair, and a separator roll pair coupled together so that the separator pair has a higher surface speed than the feed roll pair, whereby blanks passing successively through the nips of both pairs will be linearly accelerated by the separator pair together with means for adjusting the spacing between the two pairs in the feed direction, so as to achieve a distance between said nips which is less than twice the length of a discrete blank and at least substantially equal to the length of a discrete blank. The invention recognises that the spacing between the nips is critical. If contrary to the invention a distance of more than twice the length of a blank being treated exists between the two nips it would be possible for the leading end of a first blank to be engaged by the acceleration rollers when the trailing end of the immediately following blank had passed the feed rollers, and hence two successive blanks could be drawn through the acceleration rollers together and that would prevent the desired separation being achieved. On the other hand if the distance between the nips is substantially less than the length of a single discrete blank, it will be possible for one and the same blank to be seized by the feed rolls and driven forwardly at one speed, whilst also being seized by the acceleration rolls trying to drive the same blank forward at a different speed. This might damage a blank particularly a relatively fragile one made of thin card rather than heavier board. However it is possible for the spacing between the two nips to be slightly less than unit length especially where it is heavier board or a less fragile blank which is concerned. Preferably the feed rolls comprise generally cylindrical rollers geared together to be driven at the same speed, and with adjustment means for dealing with different thicknesses, or possibly spring loading to give a required nip pressure. Preferably the acceleration rolls comprise pairs of discs the two discs of each pair being co-planar, and a plurality of discs being provided adjustably along the length of a pair of parallel shafts which are geared together for synchronous drive, the discs being adjusted to positions so that, for example, two laterally spaced pairs of discs engage each blank as it passes through the nip. Thus if a particular blank configuration requires three laterally associated blanks, three pairs of such discs will be provided, and so on. The arrangement described so far provides for separation of blanks along the feed length. In order t o provide, additionally, lateral separation, we provide a second set of discs, with in this case the two discs of each pair laterally juxtaposed instead of so planar and with said two discs overlapped. These discs may be of larger diameter than the acceleration discs, and these are to be adjusted along the length of their shafts (which extend parallel to the feed rolls and the shafts carrying the acceleration discs) so that the lateral margins of each blank encounter two axially spaced discs which contact the blank on the same face. Thus for example; if three contiguous blanks are laterally disposed, a first one of these may be contacted at its laterally opposite marginal edges by a pair of discs on the upper of the two shafts, that is the one which is physically vertically above the feed plane, assuming the feed plane to be horizontal, the centre blank of the three by a pair of discs on the second shaft and which is below the feed plane, and the third blank by a further pair on the first shaft of the feed plane. Hence, the two outer blanks will be deflected downwardly from the feed plane whilst the centre blank is deflected upwardly from the feed plane and this will achieve the complete separation required, and ensure that the remaining connection between the contiguous blanks is broken. Whilst these references are to three blanks, the invention is useful with any number from two upwardly, in longitudinal or longitudinal and transverse directions. All four shafts, that is to say the two carrying the acceleration discs which achieve the longitudinal separation along the feed plane, and the two carrying the larger discs which achieve the lateral separation across the feed plane, may be coupled together in a common gear train to maintain synchronisation of the upper and lower discs and of speed of all of them relative to an input. This gear train may be coupled to the feed rollers so as to maintain speed synchronisation between the feed rollers and said gear train, so that if the speed rolls speed up or slow down, then the gear train does likewise. In general, the invention may be provided in the form of an attachment to an existing machine such as a diecutter using the feed rolls of the latter as those required by the present invention. Alternatively the invention may be put into effect in apparatus provided with its own feed rolls, including the possibility of providing the invention as the final stage in a complex apparatus including those feed rolls. Preferably, said gear train with the associated shafts is mounted on a subframe which is movable relative to the feed rolls. The movement may be achieved by a rack and pinion or equivalent. The drive between the feed rolls and the gear train may be by way of an endless belt or chain and according to a feature of the invention, jockey wheels and adjusters are avoided by using a linkage comprising three links of fixed length, pivoted together end to end, with the first link being journalled on the feed roll axis from which the drive is derived, and the third link being slidable, for example parallel to the feed plane and being fixed to the drive input shaft of said gear train at one end and to the other links of the set at its other end. Hence the first and second links can swing in position as the third link slides during movement of the gear train towards and away from the feed roll. Appropriate sprockets or pulleys are journalled on the pivotal axes of the links, and looped by corresponding belts or endless chains. The invention is more particularly described with reference to the accompanying drawing wherein the sole figure is a diagrammatic elevation of an apparatus according to the invention showing a stripper drum 10 as the final stage of a die cutting apparatus, delivering blanks along the feed path 12 to a pair of feed rolls 14 16. In this instance, the invention is applied as an add-on attachment comprising a subframe 18 providing journals for shafts carryi ng the acceleration discs 20 22 and the lateral separation or side tie breaker discs 24 26. These are all geared together by intermediate gear pinions 28 30 and drive is taken to a sprocket on the shaft carrying the acceleration discs 20 by a chain 34 (also) looped about a sprocket on axis 36 at the end of a (mainly) sliding link connecting axis 36 with the axis of the shaft carrying accelerator disc 20. A second chain 36 loops the sprocket on axis 36 with one on axis 40 at the end of a swinging link connecting axes 36 and 40 and another chain 42 connects that sprocket with one on the axis of the drive roll 16. The adjustment means for varying the spacing along the feed path 12 in the feed rolls 14 16 and the subframe 18, or more effectively between the feed rolls and the shafts carrying the acceleration discs 20 22, in this instance, comprises a fixed length of roller chain 46 carried by the subframe, and a meshed drive sprocket 48 mounted on an extension from the main frame 50. The subframe and the main frame are connected by extensible bellows or gaiter 52 to enclose the chain drive. The gap between the two frame is bridged by a series of wires 56 which are held in tension by a springloaded reel 58, so that as the subframe is moved away from the main frame, the wires are fed out to provide a support for blanks across the gap. Nip adjustment is provided by an adjuster mechanism 60 shown diagrammatically.

Claims: 1. Apparatus for board treatment comprising a feed roll pair (14 16) and a separator roll pair (20 22) coupled together (by means 34 - 42) and so that the separator pair has a higher surface speed than the feed roll pair whereby blanks passing successively through the nips of both pairs will be linearly accelerated by the separator pair, together with means (46,48) for adjusting the spacing between the two pairs in the feed direction so as to achieve a distance between said nips which is less than twice the length of a discrete blank and at least substantially equal to the length of a discrete blank. 2. Apparatus as claimed in Claim 1 wherein means (56 58) are provided for supporting the blanks in the space between the said nips. 3. Apparatus as claimed in Claim 1 wherein the coupling means comprise a drive chain (34) looped about a sprocket on a shaft carrying one of the accelerator pair (20 22) and also looped about a sprocket (36) at the end of a mainly sliding link, and connected to a sprocket on one feed roll pair (14 16) by a further pair of chains connected to an intermediate sprocket (40). 4. Apparatus as claimed in Claim 1 wherein the separator roll pair comprises a pair of discs (20 22) adjustable in position (means 60) to vary the nip between them to accommodate different board thicknesses and an associated means for providing lateral separation between contiguous blanks comprises second sets of discs (24 26) which are laterally juxtaposed and overlapped across the feed plane. 5. Apparatus as claimed in Claim 4 wherein the discs (20 22) or the discs (20 22 and 24 26) are provided in sets adjustable along the length of the drive shaft to suit requirements of individual blanks.

Inventors: MOULDS, CHRISTOPHER CHARLES, RICHARDS, MARTIN WILLIAM LANGDON, SMITH, LEONARD
Applicants: DERITEND ENGINEERING LIMITED
Application year: 1987
Main classification: B26F3
IPC codes: B26F3, B65H35