CA1157058A

CA1157058A - Method and apparatus for stacking stackable material

Info

Publication number: CA1157058A
Application number: CA000368172A
Authority: CA
Inventors: Johannes Horres
Original assignee: Saint Gobain Isover SA France
Current assignee: Saint Gobain Isover SA France
Priority date: 1980-01-09
Filing date: 1981-01-09
Publication date: 1983-11-15
Also published as: ATE13863T1; JPS56113624A; DK150741C; AU6592180A; DK6981A; EP0032367B1; ZA8189B; DK150741B; EP0032367A1; DE3170965D1; AU542418B2; NO810047L

Abstract

ABSTRACT OF THE DISCLOSURE

The specification describes a method and apparatus for stacking stackable material, in particular mineral fiberboards in a production line. Superimposed layers of one or more articles, wherein the articles associated with one layer, are introduced into a stacking space and there brought together with the previously introduced layers already forming a partial stack from the bottom. The previously formed partial stack is held spaced above the entrance plane of the layers into the stacking space and after entering the stacking space the respective new layer is raised at least a height corresponding to the thickness of the layer to be stacked and applied to the bottom of the partial stack. The previously formed partial stack is raised independently of the new layer.

Description

7~58 The invention relates to a method and apparatus for stacki,ng stackable material, in particular mineral fibre boards or plates in a production line, A number of stacking methods and stacking apparatuses have become known in which the stack is made up from below in that the partial stack formed is raised and a new layer is introduced beneath the partial stack and laid at the bottom thereof.
For example, French Patent No. 1,573,293 already dis-closes a stacking apparatus in which fork-like support members engage simultaneously from both sides between rollers of a roller track forming the stack support surface beneath the layer of articles disposed thereon and lift the layer to such an extent that a new layer can run onto the stack support surface and is then brought together with the raised layer to form a partial stack.
The layers consist of packets. When the new packet layer has run onto the stack support surface the raised partial stack is lowered by the support members or by the associated lifting means and the support elements on both sides move in opposite directions towards both sides from beneath the partial stack so that the latter comes to lie on the new layer.
Thereafter, the support members of the lifting means are moved downwardly and again engage from both sides between the rollers of the roller conveyor forming the stack support surface and raise the new partial stack thus formed in order to again provide room for a new layer, after the introduction of which into the stack space the partial stack is again .~

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lowered onto the new layer.

This stacking method operates comparatively slowly.
The useful stroke for forming the stack resides only in the travel of the fork-like support members with which the partial stack is raised to prepare for intro-duction of a new layer whilst the strokes of lowering the partial stack onto the new layer - lateral withdrawal of the support members - lowering of the support members beneath the plane of the new layer - repeated lateral moving in of the support members below the new layer -result in idle times which do not contribute in any way to the making up of the stack and during which a pre-pared new layer must be stopped from entering the stacking space. Since for reasons of mechanical loading the velocity of the support members is limited a correspon-dingly long time is required for stacking the individual layers. Since the lifting movement in the useful stroke can be carried out approximately just as quickly as the lowering movement and considerably more quickly than the ~, inward and outward movements with longer travel, the high idle time compared with the time for the useful stroke is inevitable.

To avoid such long system-inherent idle times it is known from DE-AS 2,364,751 to work with two lifting means whose likewise fork-like support members support the partial stack and the new layer in each case over the entire width. The partial stack is first raised by the support members of the one lifting means so that a new layer can be introduced into the stacking space. While the support memhers of the one lifting means hold the partial stack above the plane of the new layer the support members of the other lifting means are beneath 7(~

the plane of the new layer. By a horizolltal relative movement between the stack and the lifting means thc support men~ers of the one lifting means on the one side beneath the partial stack are withdrawn and said partial stack thus lowered onto the new layer whilst simultaneously from the other side the support members of the other lifting means engage beneath the new layer. While the support members of the latter lifting means raise the partial stack lowered onto the new layer together with the latter the support members of the other lifting means are again lowered and are ready to engage beneath the next new layer when the corresponding horizontal relative movement is executed.

Theoretically, this should reduce by about half the amount of system-inherent idle times because the two lifting means operate alternately and consequently in a full cycle of a lifting means comprising the individual strokes raising - withdrawal movement - lowering -engagement movement in each case two new layers are added to the partial stack. However, in practice no reduction of the time required for the stacking of a .new layer is achieved because firstly the lifting means are much heavier because the support members of each lifting means are subjected to the load of the entire weight of the stack, in the case of example a package stack, with great leverage, and secondly the travels for the engagement movement and withdrawal movement of the support members are more than twice as great com-pared with the support members of a lifting means .
engaging from both sides. Consequently, on the whole considerably greater masses must be accelerated and longer travels covered so that the theoretical advantage of the alternating mode of operation of two lifting means is not realised in practice.

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DE-GbmS 7,220,758 or US-PS 3,~2,~00 discloscs a further modification of such a s~acking method in which the stackin~ support surface serves as ].ifting platform and the respective lowermost layer of the raised partial stack is engaged in the raised position of the lifting platform by support mernbers of an upper holding means which hold the partial stack in the raised position wherea~ter the lif-ting platform can.be relowered for the introduc-tion of a new layer. To .
avoid the lowermost layer being subjected to lateral pressure during the supporting in the raised position, which with the package layers stacked therein and in most other cases is not permissible, the support members of the holding means are also made fork-like and dis-placeable horizontally in such a manner that they can be moved out from the region beneath the previously formed partial stack towards both sides. The lifting platform must first lift the lowermost layer to such an extent that it bears directly on the bottom of the partial stack or the support members whereupon the latter can be withdrawn to completely deposit the partial stack on the new layer; a further lifting movement of the lifting platform can then take place until the new lowermost layer llas moved above the plane of the support members so that the latter can be moved in again and in the raised position can support the new lowermost layer with the partial stack disposed there-above o~ relo~ering oE the liftin~ platform.

Ilowever, such a vertically stationary holding means also cannot increase the working speed compared with the first stacking method mentioned accordin~ to FR-PS 1,573,293 because the raising and lowering movement of the support members therein is merely replaced by the correspondin~

~ 7(~S~3 raising and lowering movement of the lifting ~latform and the idle time for the lateral moving in and withdrawal of the support members remains unchanged. Also, a new layer cannot be introduced until the lifting platform, which forms the stack support surface, has returned to its lower position so that as regards the time required for stacking a new layer the same conditions apply as those explained above in conjunction with the stacking method according to FR-PS 1,573,293.
The method according to the invention proceeds from the method according to DE-GbmS 7,220,758 in which the new layer is combined with the previously formed partial stack in that the new layer is first applied with its top to the bottom of the previously formed partial stack and the new layer then raised together with the paxtial stack resting thereon via the working stroke. This requires that the support members at the bottom of the previously formed stack must be withdrawn from between said stack and the new layer before the working stroke can take place.
Furthermore, the invention proceeds from the apparatus according to DE-AS 2,364,751 in which the stack support surface is disposed stationary and instead two alternately operating lifting means are provided. However, in spite of the alternating mode of operation of two lifting means in practice, for the reasons outlined in detail above, the time requirement is not appreciably reduced because due to the considerably higher mechanical load greater weights must be accelerated and retarded and moreover greater distances must be covered.
Proceeding from the prior art outlined, as regards the method and apparatus the invention is based on the problem of sd/`~, -5-.

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further developing the stacking method according to DE-GbmS
7,220,758 and the stacking apparatus according to DE-AS 2,364,751 so that in the simplest possible manner a considerably higher stacking rate can be achieved which permits the use of the method or apparatus according to the invention in particular for stacking mineral fibre boards in a production line with continuous and rapid succession of mineral fibre boards or formations.
The above problem is solved in the present invention by way of a method of stacking stackable material, in particular mineral fibre boards in a production line, in superimposed layers of one or more articles, wherein the articles forming a new layer are introduced into a stacking space and there brought together with the previously introduced layers already forming a partial stack from the bottom thereof, the previous formed partial stack being held spaced above the entrance plane of the layers into the stacking space and after entering the stacking space the respective new layer being raised at least a height corresponding to the thickness of the layer to be stacked and characterized in that the previously formed partial stack is, at least at the beginning of the raising movement of the new layer, kept supported independently of the new layer and is also raised concurrently with the new layer so as to maintain a vertical distance between the bottom of the partial skack and the upper surface of the new layer.
Because the previously formed partial stack is raised independently of the new layer it is not necessary to wait with the useful stroke until the support elements have been withdrawn from beneath the previously formed stack in order to be able to sd/'`~ 6-3L~57~5~

raise the partial stack together with the new layer. On the contrary, the partial stack can be raised separately from the new layer to a height permitting the lift movement thereof in such a manner that the new layer can perform its entire desired lift movement in one go. At the end of the lift movement or even during said movement the lowering of the partial stack onto the new layer by withdrawing the support members can take place or at least begin. If the previously formed partial stack is raised simultaneously with the new layer but possibly by a smaller amount than the new layer a soft placing of the previously formed partial stack on the new layer is achieved with small drop height.
However, the lift movement of the partial stack can take place for example also prior to the lift movement of the new layer and/or to the same extent as the lift movement of the new layer and any gap between the bottom of the partial stack and the top of the new layer is bridged by a corresponding lowering or drop movement of the partial stack.
In any case, due to the step of a lift movement of the partial stack controllable independently of the lift movement of the new layer the useful stroke of the new layer can take place in one go and at the same time the deposition of the partial stack on the top of the new layer can possibly begin.
On the other hand, the present invention also relates to apparatus for stacking stackable material, in particular mineral fibre boards in a production line, in superimposed layers of one or more articles, comprising a) a plurality of lifting means for the layers of the articles for achieving the vertical displacement of the layers in formation of the stack, sd/i~ 7 , .

b) a stationary ]ower stack support surface, c) a stop disposed in the entrance direction of the layers behind the stacking space for aligned stopping of the respective new layer introduced and d) a conveying means for carrying away the finished stack, wherein each lifting means comprises at least one support member for the layers which is aligned at least approximately parallel to the stack support surface and which can be moved from the side beneath the stack and after the completed lifting can be withdrawn again from the stacking space, and which in the vertical direction is moveable relatively to the support member of one of the other lifting means, characterized in that the support members of one of the lifting means are mounted relatively moveable in a horizontal direction with respect to those of at least one of the other lifting means, that the support members of each lifting means during vertical movement pass through the support members of another lifting means lying on the same side of the stack space, and that the support members are formed as fork arms, the fork arms being offset to an extent permitting vertical mutual passage thereof with respect to the fork arms of another lifting means lying on the same side of the stacking space.
For solving the problem as regards the apparatus, firstly use may be made o two lifting means which operate alternately. It is however additionally achieved that such an alternating mode of operation of two lifting means can take place even when each lifting means comprises support members known per se from FR-PS 1,573,~93 and adapted to be moved into the stacking space and withdrawn therefrom on both sides so that sd/~ 8 ~

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-there is no need to have recourse to the heavier construction of the lifting means operating with longer engagement and with-drawal travels according to DE~AS 2,364,751. Alternatively, howe!ver, a construction of the lifting means and the support members extending over the entire width of the stack according to DE-AS 2,364,751 may be used but then at each side of the stacking space of the apparatus two lifting means with support members extending over the entire stack width are provided so that one of the four sets of support members can perform a working stroke while the remaining three sets of support members run in the idle strokes withdrawal-lowering-engagement, i.e. inward movement. The alternating mode of operation of four lifting means mean that for a given working frequency or stacking rate a lower absolute speed of the machine parts is necessary. In any case, according to the invention the support members of a lifting means are relatively moveable with respect to those of at least one other lifting means not only in the vertical direction but also in the horizontal direction and an alternating operation of sets of support members disposed on the same side of the stack is achieved in that the support members of a lifting means during the vertical relative movement pass through the support members of another lifting means disposed on the same side of the stacking space so that for ~ example fork-like support members of different llfting means .~ may be disposed alternately above and below each other.
In each case it is achieved with the stationary stack ; support surface compared with a construction of the stack support surface as lifting platform in addition that immediately sd/~ A-~

after raising the introduced new layer the stack support surface is free for the run-in of the next layer.
Use of the method according to the invention results in the important advantage that each new layer introduced onto the stack support surface is lifted into a raised position which permits the run-in of the next layer and remains during the further operating steps in at least this raised position. Thus, immediately after the raising of a layer ~ sd/ ~ ~ -8B-.
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the stacking space is ~vailable for the introduction of a new layer and the working strokes necessary for preparing a raising of this new layer can be carried out whilst the new layer runs into the stacking space.
With suitable design and control of the lifting means the theoretically shortest possible interval between successive layers entering the stacking space depends on the tirne interval which is necessary to raise a layer introduced into the stacking space from the stacking support surface to such a height that a new layer can enter beneath the pre~iously introduced layer.

The.invention will be explained hereinafter with the aid of examples of embodiment illustrated in the drawings, wherein: :
Fig. 1 in two parts I and II on two sheets of drawings shows diagrammatically simplified a plan view of a production line for making mineral fibre boards with stacking in an apparatus according to the invention and subsequent packing, Fig. 2 shows diagrammatically simplified a perspective view of the essential parts of an apparatus according to the invention and their mutual positions, the upper lifting means with its support members being shown removed upwardly from the lower lifting means and the stack support surface for clarity, ~ig. 3 shows in individual illustrations a) to d) a schematic representation of a possible mode of operation of the apparatus according to Fig. 2, _ g _ ;

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Fig. 4 shows in individual illustrations a) to k) a diagra~latic representation of another possible mode of operation of the apparatus according to Fig. 2 and in indi.vidual illustrations 1) to v) a diagrammatic illustration of the st~cking space seen from the side with the preceding part of the production line, each of the individual illustrations 1) to v) corresponding to the positions of the apparatus according to the invention acco.rding to the individual illus-trations a) to k), Fig. 5 shows in en].arged individual illustrations a) to e) the posit~n of the support members in dot-dash circles Va, Ve in Figs. 4c and d during the passage through these positions and in intermediate positions, and Fig. 6 shows individual illustrations a) to k) a ~, .
d~grammatic representation of a mode of oper-ation, corresponding substantially to the mode of operation according to Fig. 4, of an embodi-ment of the apparatus according to the invention modified compared with the representation in Fig. 2.

Although the invention is not restricted to the use for stacking mineral fibre boards orjsimilar boards or plates in a production line, hereinafter with the aid of Fig. 1 firstly the makeup and mode o~ operation of such a production line will be explained because the method according to the invention and the apparatus according to the invention are particularly suitable for fulfilling the requirements encountered typically in continuously operating production lines of this or similar types.
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, '';: ~ ` ~ , , .-``. ~,.~ S7~8 The mineral fibres prodllced by fibre producing heads out of a melt in a known manner are suitably treated with additives such as binders and are cont:inuously deposited for further treatment, e.g. drying, on a conveyor band, while forming a ~ibrous bonded web on the conveyor, the end of which is generally shown at 2 on the left hand end - or, with respect to the direction of production according to arrow 1, the upstream end - of figure 1. If mineral fibre boards narrower than the production width, which is dependent on the number and disposition of the fibre producing heads, are to be produced the web may be cut into a plurality of longitudinal strips 21a;21b in amannerknown per se, for example by high-pressure water jets, whilst being conveyed. At the end o~ the conveyor belt 2 there is a saw 3 which in the manner of so called flying shears cuts the fibre web transversely o~ the produc-tion direction according to the arrow 1 to produce the desired longitudinal extent of the mineral ~ibre boards.

The boards emerging at the rear side of the saw 3 in the production direction according to the arrow 1 are taken over by a belt 4 running with the same speed as the conveyor belt 2 and, in case of the example shown, supplied to a fulling means 5. The fulling means 5 is followed by an accelerating belt 6 which accelerates the boards leaving the fulling means 5 with respect to thç speed on the conveyor belt 2 and the belt and separates them in this manner`so that inter-vals are formed between successive boards or board rows. F`rom the accelerating belt 6 the boards thus separated pass via an alignment belt 7 onto a retaining belt 8 and pass preliminary and main alignment members 9a and 9b in the form of guide bars or rails which align the boards arriving centrally with .. . , . ~

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respect to the centre axis of the production line and close gaps next to laterally adjacent boards. At the end of the retaining belt 8 a retaining stop 10 is provided substantially in the form of a row of re-taining bolts with which the boards transferred with the.speed of the accelerating belt 6 via the alignmen-t belt 7 to the retaining belt 8 can be selectively retarded.

Following the retaining stop 10 is a stacking apparatus designated overall by 11, the construction and mode of operation of which will be explained in detail herei.n-after. In the stacking apparatus ll the boards .
entering are stacked on each other in layers until the desired stack height is reached ~hereupon the finished packet-like stack runs .in the production direction according to the arrow 1 at the back of the stacking apparatus 11 onto a discharge belt 20 and depending upon the type of board or package is supplied to a subsequent packing station 12, 13 or 14. For this purpose the stacks pass from the discharge belt 20 firstly to an angle transfer station 15 from whence they are transferred either on one side to conveyor belts 16 a and 16b or on the other side to a conveyor means 17 or, continuing in the production direction, to a further angle transfer station 18; the angle transfer station 18 transfers to a further angle transfer station 19 in continuation of the conveyor means 17 at the entrance of the packing station 12. The packing st.ation 12 can thus be reached from the angle transfer station 15 either via the conveyor means 17, the stacks being turned with respect to the alignment on the discharge belt 20 by the curve of the conveyor means 17 ~cf. Fig. 1) through 90, or alternatively via the . - 12 --, . . , ~ ': ~ , ., ; , . :. ;

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angle transfer stations 18 and 19, between which only a parallel displacement of the stacks takes place so that their alignment with respect to the alignment on the discharge belt 20 is not changed.

The makeup of the end region of the produc-tion line illustrated above in principle with the stackinq apparatus 11 will be explained in detail with regard to its mode of operation hereinafter with the aid of a concrete embodiment. The production line illustrated can be designed for producing mineral fibre boards witli greatly varying dimensions, for example a length of the boards between 330 and 3200 mrn, a width of the boards between 250 and 1250 mm and a height of the boards between 10 mm and 200 mm, and the fibre web may ~e cut into parallel strips to produce up to five boards of smaller width adjacent each other in - the production direction according to the arrow 1 by the saw 3. In the example it is assumed that the boards are to be made with a length of 1500 mm and a width of 600 mm and in Fig. 1 for this case in dot-dash line the instantaneous arrangement of the individual mineral fibre boards designated by 21 on the production line is illustrated. The conveyor belt 2 of the production line may have a speed of 30 m/min and supplies two adjacent strips, designated by 21a and 21b, of the fibre material to the saw 3. The saw 3 runs with a frequency of 20 min 1, i.e. per minute executes 20 cuts at equal intervals of time so that the strips 21a and 21b are given a transverse cut in the region of the saw 3 at intervals of 1500 mm; in the illustration chosen such a transverse cut is just being rnade in the region of the saw 3. The mineral fibre boards 21 thUS formed and having a width of 600 mm, corresponding :, . , ; , :

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3 5 ~3 to the width of the strips 21a and 21b, and a length of 1500 mm, run after the saw 3 substantially without relative movement onto the belt 4 to the fulling means 5. As soon as the trailing ends of the mineral fibre boards 21 emerge from the engage-ment region of the fulling means 5 the mineral fibre boards 21 are accelerated, lying adjacent each other in pairs, b~ the accelerating belt 6. Like the alignment belt 7 and the retaining belt 8 as well as the discharge belt 20 the accelerating belt 6 may run at a speed of about 90 m/min, that is about 3 times the speed of the conveyor belt 2 and the belt 4. The adjacent pairs of mineral fibre boards 21 are thereby separated so that between consecutive board pairs intervals of the order of magnitude of 3000mm form which with the speed of the faster running belts 6, 7 and 8 corresponds to a time interval of about 2 s between the trailing edge of the leading pair of mineral fibre boards 21 and the leading edge of a following pair of mineral fibre boards 21.

A pair of mineral fibre boards 21 is just being retained by the retaining stop 10 at the rear end of the re-taining belt 8 and the following pair of mineral fibre boards 21 is just about to strike the rear end of retained pair. By a vibration pickup disposed in the region of the retaining belt 8 but not illustrated the shock occurring when a board pair strikes the retaining stop 10 can be measured so that after a predetermined number of shocks, after two shocks .in the case of the example, the retaining stop 10 is removed from the transport path for the time required by a stack layer 22 formed on the retaining belt 8 from a plurality of successive arriving board formations to move over with its rear end the region of the retaining stop 10.

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In the instantaneous illustration chosen the board pair 21 trailing on the retaining belt strikes in just under one second the trailing edge o the already retained board pair 21 and thus produces a second shock detected by the vibration picXup, whereupon for example by means of a hydraulic control the retaining bolts forming the retaining stop 10 can be lowered for a time of about 3 s to allow the layer 22 formed on the retainirlg belt 8 and comprising four mineral fibre boards 21 to enter the stacking apparatus 11 without further relative movement. Of course, the trailing end of the board formation entering the stacking apparatus 11 can also be detected by means of a light barrier or the like, whereupon the retaining stop 10 again moves to its stop position and again stops the leading edge of the following pair of mineral fibre boards 21.

In the region of the stacXing apparatus 11 there is a stacking space 23 in which a plurality of layers 22 is stacked in the manner explained in detail herein-after. In the case of the example it is assumed that before the two board pairs 21 disposed in the region of the retaining belt 8 a first layer 22 of a new stack has just entered the stacking apparatus 10 and in the region of the end of the discharge belt 20 just :-before the angle transfer station 15 a finished stack is shown comprising a plurality of stacked layers 22 which is to be supplied via the angle transfer stations 18 and 19 to the packing station 12.

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Thus, in the example chosen layers 22 formed contin-uously in succession at intervals of about 6 s run on the retaining belt 8 into the stacking space 23 of the stacking apparatus 11 so that the stacking of the layers 22 and the stacking of the last layer 22 of the stack, including the discharge of the finished stack, must take place wit}lin a time frequency of about 6 s. As readily apparent the cycle time available to the stacking apparatus 11 is still smaller if with the same production rate of 30 m/min corresponding to the speed of the conveyor belt 2 less favourable board lengths are to be stacked, for example a board length of somewhat more than half the utilisable length of the stacking space 23, in the case of the example of more than 1600 mm, assuming the utilisable length of the stacking space 23 to be 3200 mm. Formation of board arrays in the region of the retaining belt 8 is then not possible and consequent-ly the retaining stop 10 remains permanently lowered and the boards or board pairs 21, to whose width the adjustable alignment members 9a and 9b are set, enter the stacking space 23 with a speed which is not dimin-ished with respect to the speed of the belts 6, 7 and 8, without stopping. As is readily apparent if the board length is increased to 16~ mm from the 1500 mm assumed in the example and the boards run directly individually into the stacking space 23 for stacking the individual layers 22 in the stacking apparatus 11 and for stacking the last layer 22 of the stack, including dischar~e of the finished stack, the time available is onl~ slightly more than 3 s. The cycle time re~uired from the stacking apparatus 10 of course becomes still smaller in proportion to the increase of the production rate i beyond 30 m/min so that with a predetermined cycle time -. - ~6 -;, - . , ... .. , , ~ :

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of the stacking apparatus 11 of for example 2 s for each particular board dimension and stack formation to be produced a maximum permissible production rate above about 30 m/min results whilst beneath a production rate of about 30 m/min with a utilisable length of the stacking space 23 of 32~ mm with a cycle time of about 2 s any stackable board size whatever can be stacked easily and for favourable board dimensions without increasing the production rate the stacking apparatus may be operated more slowly than the maximum possible rate. Thus, in the example of embodiment instead of a frequency of 30 min 1 corresponding to a cycle time of 2 s any lower frequency down to about 4.5 min 1 may be set.

The basic construction of the stacking apparatus 11 will be explained in detail hereinafter with the aid of Fig. 2. According to the latter a stacking apparatus 11 corresponding to the present embodiment ;
comprises two lifting means 24 and 25, the lower li~ting means 24 comprising two lifting tables 26 and 27 on both sides of a stack support surface 30 defining the bottom of the stacking space 23 and the upper lifting means 25 comprising two correspondingly disposed lifting tables 28 and 29. The lifting tables 26, 27 and 28, 29 are mounted movably up and down in a manner not illustrated in detail on vertical guides of a machine frame of the stacking apparatus 11 as indicated by-the douhle arrows 31, for which purpose a great number of construction alternatives is available. As lifting drive for the lifting platforms or tables 26, 27 and 28, 29 in the case of the example hydraulic cylinders may be used. The lifting tables 26 and 27 on the one hand and 28 and 29 on the other, each forming part of one of the lifting means 24 and 25, always move .

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synchronously in the direction of the double arrows 31 and the driving hydraulic cylinders may be matched in pairs in volume or alternatively for example a mechanical synchronous control may be used as is known per se. Since the lifting tables 26, 27 on the one hand and 28, 29 on the other are always moved syn-chronously up and down as unit they form together in each case only one unitary lifting means 29 and 25 respectively.

At the bottom of the upper lifting tables 28 and 29 of the uppèr lifting means 25, which are shown in Fig. 2 for clarity removed upwardly from the remaining illustrated parts of the stacking apparatus 11, slides 35 and 36 horizontally movable as indicated by the double arrows 32 are disposed whilst at the top of the lower lifting tables 26 and 27 of the lower lifting means 24 slides 33 and 34 likewise movable horizontally as indicated by the double arrows 32 are disposed. At the top of the lower slides 33 and 34 via spacers37 and 38 substantially horizontally aligned fork-like support members 41, 42 are mounted spaced from the lifting tables 26 and 27 and the slides 33 and 34 whereas at the bottom of the slides 35 and 36 via spacers39 and 40 fork-like support members 43 and 44 are mounted vertically spaced beneath the lifting tables 28 and 29 and the slides 35 and 36. The fork-like support members 41 and 43 together with the associated spacers 37 and 39 on one side of the stack support surface 30 on the one hand and the support members 42 and 44 together with the spacers 38 and 40 on the opposite side of the stack support surface 30 on the other are offset with respect to each other in the production direction according to the arrow 1 so that the support members 41 and 43 . ~
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lifting tables 26 and 28 and 27 and 29 respectively are moved towards each other according to the double arrows 31. The vertical free height of the spacers 37, 38, 39 and 40 is chosen so that with the narrowest operational arrangement of the lifting tables 26, 27, 28 and 29 above each other the support members 43 and 44 on the upper lifting tables 2~ and 29 come to lie at such a spacing beneath the support members 41 and 42 on the lower lifting tables 26 and 27 that between the lower support members 41 and 42 and the upper support members 43 and 44 and stack support surace 30 a new layer 22 of mineral fibre boards 21 can be introduced onto the stack support surface 30.
Depending on the mode of operation of the stacking ~"
apparatus 11 chosen this maximum distance between the lower support members 43 and 44 and upper support members 41 and 42 can also be made greater without difficulty by corresponding dimensioning of the spacers 37, 38, 39 and 40 so that as a result: a mutual penetration of the support members 41, 42 on the one hand and 43, 44 on the other is achieved to the extent necessary for the working position in operation having the corresponding maximum spacing.

The support members 41 and 42 of the lifting means 24 and the support members 43 and 44 of the lifting means 25 are however, in the embodiment illustrated, not aligned with the respective gap but lie in each oper-ating position in alignment. In the illustration shown in Fig. 2 the horizontally movable slides 33, 34, 35 and 36 are in each case in their 1nnermost position adjacent the stack suppoxt surface 30, the support members 41 and 42 on the one hand and 43 and 44 on the other of each lifting means 24 and 25 respectively lying with their tips a slight distance apart. As indicated by the double arrGws 32 all the ' :

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s].ides 33, 34, 35 and 36 may move outwardly out of the position illustrated alony the lifting tables 26, 27, 2~ and 29 away from the stack support surface 30 into a position in which the facing ends of the support members 41, 42 and 43, 44 have a distance apart which is greater than the width measured trans-versely of the production direction according to the arrow 1 o~ the stack support surface 30 or the stack to be formed thereon. In such an outer position the support members 41, 42 and 43, 44 are withdrawn laterally from a stack or partial stack formed on the stack support surface 30 whilst in the illustration chosen they are moved in and can lift a layer 22 on the stack support surface 3~ from below and support said layer above the stack support surface 30 in a raised position. In the illustration according to Fig. 2 the support members 41 and 42 of the lower lifting means 24 are moved in beneath the stack support surface 30 and could therefore lift a layer 22 lying on the stack support surface off the latter whilst an already formed partial stack could be held spaced above the stack support surface 30 on the support members 43 and 44 of the upper lifting means 25.

The stack support surface 30 is formed by the upper points of the rollers 45 of a roller conveyor. The rollers 45 have a mutual spacing which permits a simultaneous entrance of the support members 41, 42 on the one hand and 43, 44 on the other betweel1 the rollers beneath the stack support surface 30 but are otherwise as close together as possible to permit as uniform as possible supportin~ of the layers 22 on the upper points of the rollers 45. To convey the layers 22 in the production direction 1 on entry and discharge thereof the rollers 45 can be driven as indicated by the arrow 46 and are driven as required - : . :

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7~8 or continuously. Individual rol].ers 45 may be provided with a rubber or other friction-increasing coating to obtain desired accelerations of the layers 22, in particular on discharge of the finished stack from the stacking space 23. At the rear end of the stacking space 23 or stack support surface 30, considered in the production direction according to the arrow 1, a retaining stop 47 is provided which consists in the example of embodiment of a row of retaining bolts or pins 48 which can be raised or lowered as indicated by the do~lble arrow 49. In the raised position the retaining pins 48 block the discharge of a layer 22 lying on the stack support surface 30 so that in spite of the possibly permanently running rollers 45 said layer remains stationary on the stack support surface 30 and can be lifted by the support members 41, 42 or 43, 40 without relative movement from the stack support surface 30. After formation of the complete stack the retaining pins 48 are for eY.ample hydraulically lowered so that the finished stack, driven by the rollers 45, can move in the production direction according to the arrow 1 out o the stacking space 23 and onto the discharge belt 20 which at least in its region adjoining the stacking apparatus 11 can if necessary also be formed by rollers which by provision of a rubber covering or the like give rapid acceleration of the stack to the running speed of the discharge belt 20.

In Fig. 3, which like the following Figs. 4 and 6 shows in still further diagrammatically simpli~ied manner only the components of the stacking apparatus necessary for understanding the mode of operation, a possible mode of operation of the stacking apparatus 11 according to Fig. 2 is shown in detail. Fig, 3a shows an instant in the course of the stacking operation which .. . .

.

has already led to formation of a partial stack of two layers 22 and in which the support members 41 and 42 of the lower lifting means 2~ are moved in beneath the stack support surface 30 and ready to lift the partial stack comprising the two layers 22 whilst the support members 43 and 44 have just been withdrawn from between the two layers 22 of the partial stack.

To prepare for the entry of the following layer 22 the support members 41 and 42 then lift the partial stack comprising the two layers 22 into the position according to Fig. 3b in which the new layer 22 is shown already introduced onto the stack support surface 30. The introduction movement of the new layer 22 is terminated by the retaining stop 47 so that the new layer 22 lies on the stack support surface 30 in alignment with the raised partial stack. Simultan-eously, the support members 43 and 44 of the lifting means 24 are moved downwardly into a plane beneath the stack support surface 30 and in the manner clearly shown in Fig. 3b they pass throuyh the plane of the support members 41 and 42 of the lifting means 24 and come to rest beneath the plane of the support members 41 and 42. The mutual interpassage of the support members 41 and 42 and 43 and 44 respectively is made possible by the spacers 37, 38 and 39, 40 as already explained above in connection with Fig. 2 and by the support members 41, 42 on the one hand and 43, 44 on the other being offset with respect to each other in the production direction according to the arrow 1, i.e. being so to say in gap alignment and thus not colliding during the interpassage in the vertical direction.

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.

Once the new layer 22 has moved completely onto the stack support surface 30 in accordance with Fig. 3b by actuating the slides 33 and 34 the support men~ers 41 and 42 of the lower lifting means 24 according to Fig. 3c are movea out of the gap between the new layer 22 an~ the previously formed partial stack, possibly after a previous slight lowering movement for bringing the bottom of the partial stack closer to the top of the new layer 22 so that the partial stack is gently lowered onto the new layer 22 lying on the stack support surface 30. Simultaneously with the with-drawal movement of the support members 41 and 42 of the lifting means 24 the support members 43 and 44 of the lifting means 25 move beneath the stack support sur-face 30 and are now in turn ready to lift the partial stack formed by the three layers 22 according to Fig. 3c. In Fig. 3d the position of the support members 43 and 44 at the end of this lifting movement is shown and a further layer 22 is shown already introduced onto the stack support surface 30. Simultaneously with the lifting movement of the lifting means 25 the lowering of the lifting means 24 takes place into the position according to Fig. 3d where the support members 41 and 42 of the lifting means 24 are ready to move in beneath the stack support surface 30 into the position according to Fig. 3a when the support members 43 and 44 of the lifting means 25 are again withdrawn into the position according to Fig. 3a. Following the inward and outward movement outlined of the support mem~ers 41, 42 and 43,44 respectively, proceeding from the working position according to Fig. 3d thc working position according to Fig. 3a is again assumed but with the difference that there are now four layers 22 on the stack support surface 30 instead of the two layers 22 according to Fig. 3a and the four layers 22 can now be raised to permit introduction of a fifth layer "1 .

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S70~8 onto the stack support surface 30.

The support members 41,42 and ~3, 44 may be controlled in the manner apparent from Figs. 3a to 3d 60 that an opposite inward and withdrawal movement or lifting movement always takes place simultaneously so that by an exact anticyclic mode of operation of the support members 41, 42 and 43, 44 respectively hardly any time losses occur and the great advantage is achieved that a mass balancing can be obtained between the moving parts so that extremely short cycle times may be obtained. In addition, of course, the control is simplified so that for example the liting tables 26, 27 and 28, 29 can be positively connected for instance via racks and gears.
f However, the mode of operation of the stacking apparatus 11 illustrated in Fig. 3 has the disadvantage that after the introduction of a new layer 22 onto the stack support surface firstly the previously formed partial stack must be lowered by lateral withdrawal of the corresponding support members onto the top of the new layer 22 and only thereafter can the new layer 22 be lifted together with the previously formed partial stack deposited thereon before a new layer 22 can be introduced onto the stack support surface 30. Ilowever, it is precisely the interval in which a newly introduced layer 22, stopped by the rear retaining stop 47, lies ~ on the stack support surface 30 before the lifting takes I place which is critical in so far as it governs tl1e magnitude of the necessary minimum distance between the trailing edge of the layer 22 just introduced and the leading edge of the following layer 22 on the retaining belt 8 because these two edges of the successive layers 22 must not collide. Since each layer 22 usually has at least a length corresponding to half the length of `:

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the stack support surface 30 said layer requires for its introduction until reaclling the rear retain-ing pins 48 a quite considerable time of about 2 s in the embodiment according to Fig. 1 and during this time the support members lifting the partial stack must remain in this position before the upper partial stack can be lowered onto thc aligned stopped and stationary new layer 22. Whereas the time required for the actual lifting movement between Figs. 3a and 3b or 3c and 3d may be only about 0.2 s the stacking apparatus 11 must therefore remain about two seconds in the position reached in ~igs.3b or 3c to wait for complete entry of the lower layer 22 before the support members supporting the partial stack can be withdrawn laterally therefrom and the partial stack deposited on the new layer 22. ~ :

In the form of the mode of operation of the apparatus according to Fig. 2 explained with the aid of Fig. 4 a solution has been found with which the necessary minimum time interval between the trailing edge of the preceding layer 22 and the leading edge of a following layer 22 is substantial1y reduced to the .`
time which is actually required solely for carrying out the li~ting movement of a layer 22 introduced onto the stack support surface 30 and stopped by the rear retaining stop 47.

To illustrate this in Fig. 4a firstly a startlng con-dition is shown in which both lifting means 24 and 25 are in their lowered position so that all the support members 41, 42, 43 and 44 lie beneath the stack support surface 30 and ready for a lifting move-ment. As Fig. 4l shows in another view a first layer 221 introduced onto the stack support surface 30 has just been stopped by the retaining pins 48 of the .

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retailling stop 47. As also illustrated in Fig. 41 the follo~ing second layer 222 is already jus~ in front of the retaining stop 10 of ~lle retaininy belt 8 and is thus ready for introduction onto the stack support surface 30. For simplification it ~lill be assumed in the present example that one-piece board lengths are to be stacked as layers 22 so that no actuation of the retaining stop 10 is necessary for forming a board array of a plurality of successively acumulated mineral fibre boards 21.

From the position according to Fig. 4a the lifting means 25 with the lifting tables 28 and 29 is first actuated so that the support membexs 43 and 44 move upwardly, passing through the stack support surface 30, through a height h1 (c~.Fig.4b;m) so that the new layer 222 can be introduced onto the stack support surface.
As a comparison of the positions of the layer 222 in the associated Figs. 41 and 4m shows during this short lifting movement, which can last for example 0.2 s, the layer 222 has been moved only a very small distance onto the stacking apparatus 11. The height h1 corresponds to the sum of the thickness of each layer 22, a safety distance of or example 20 mm for introduction of the layer 222 between the lower edge of the support members 41, 42, 43 and 44 and the upper edge of the layer 222 on the stack support surface 30, plus the maximum vertical thickne~ss of the support members 41, 42, 43 or 44 in the region of the width of the layer 222, and plus a safety distance of for example 5 mm between the lower edge of the layer 22 on the stack support surface 30 and the nearest upper edge of the support members 41, 42, 43 or 44 disposed in the region of the width of the layers 22.

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A~ter the lifting of the layer 221 according to Fig. 4b and 4m by the lifting movement of the support members 43 and 44 through the height h1 the stack support surface 30 is free for the introduction of the second layer 222 as apparent from Figs. 4c and 4n. As soon as the layer 222 has reached the retaining stop 47 the support members 41 and 42 of the lifting means 24 lift the layer 222 from the stack support surface 30 through the height h1. Simultaneously, as shown by Figs. 4d and 40, the layer 221 is lifted by means of the support members 43 and 44 through an additional height h2 which may correspond in magnitude to the height h1 or be somewhat smaller. Simultaneously with the further raising of the layer 222 the outward movement of the support members 43 and 44 from the yap between the layers 221 and 222 begins so that in combination with the lifting movement of the support members 43 and 44 through the height h2 providing room for the outwardly moving layer 222 a gentle depos-iting of the layer 221 on the layer 222 results whilst the latter remains in the position raised throuyh the height h1 to permit introduction of the following layer As apparent from Figs. 4e and 4p the already delivered layer 223 can now run into the region beneath the raised support members 41 and 42 onto the stack support surface 30 and is in turn stopped by the retaining stop 47.
During the introduction of the layer 223 the lifting means 25 with the support members 43 and 44 is lowered through the sum of the heightshl and h2 and the support members 43 and q4 are moved towards each other by means of the s~des 35 and 36 beneath the stac~ support surface 30 into the position according to Figs. 4e and 4p so that they are ready for a repeated lifting movement.
This movement of the support members 43, 44 downwardly , 7~38 and inwardly out of the position according to Fig. 9d into the position according to Fig. 4e requires for example a time of just less than 2 s which corresponds to the order of magnitude of the interval required by the leading edge of the layer 223 to pass from the leadin~ edge of the stack support surface 30 out to the retaining stop 47. In this time the following layer 224 moves in the manner shown in Fig. 4p with the same speed and consequently, when the layer 223 reaches the retaining stop 47, is located with its leading edge just before the start of the stack support surface 30 as illustrated by Figs. 4f and 4q. As a rule the support members 43 and 44 have reached their'waiting position for the next stroke before the entering layer 223 has reached the retaining stop 47, substantially in the position thereof according to Fig. 4p.

When the new layer 223 has reached the retaining stop 47 according to Figs. 4f and 4q a lifting mo~ment of the support members 43 and 44 of the lifting means 25 again takes place through the height h1 together with a simultaneous lifting movement through the height h2 with simultaneous outward movement of the support members 41, 42. This position is illustrated in Figs. 4g and 4r and immediately after the completed lifting movement of the support members 43 and 44 the stack support surface 30 is free,for the entry of the following layer 224 irrespective of whether or not the support members 41 and 42 are already completely withdrawn. Due to the greater travel the inward and outward movement of the support members usually takes considerably longer, for example 1.5 s, than the lifting movement through the height h1 or h2, which can be concluded in a time of the order of magnitude of 0.2 s, .~
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Consequently, after conclusion of the lifting movement of the support members 43 and 44 through thc hei~ht h1 and the parallel liftin~ movement of the support members 41 and 42 through the height h2 the withdrawal movement of the support members 41 and 42 can be concluded whilst the leading edge of the following layer 224 already enters the region of the stack support surface 30.

Figs. 4h and 4s lllustrate -thc completed downward movemen~
of the support members in the uppermost position, in the present case the support members 41 and 42, to below the plane of the stack support surface 30 and the moving in of the support members 41 and 42 in readiness for the next lifting movement whilst the layer 224 is still moving on the stack support surface 30 in the direction towards the rear retaining stop 47. According to Figs. 4i and 4t when the 'ayer 224 reaches the retaining stop 47 the lower support members 41 and 42 have already in their readiness position for the next lifting stroke for an appreciable time and if required can immediately again raise the stopped layer 224 to make room for the following layer 225.

However, in the present case it will be assum~ that only four layers 22 are to form a completed stack. The ; lowered support members 41 and 42 then remain in the position according to Figs. 4i and 4t and only the support members 43 and 44, possibly after a slight downward movement, move laterally out of the gap between the layer 223 and 224 so that the previously formed partial stack comprising three layers can be deposited on the layer 224 resting on the stack support surface.
Thus, in the manner shown in Figs. 4j and 4u the finished ,:

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stack of four layers 22 is on the stack support surface 30 and the retaining stop 47 is lowered as apparent from Fi~. 4u. The driven rollers 45 then accelerate the stack via the lowermost layer 224 thereof past the rear end of the stack support surface 30 onto which the next layer 225 is already moving (Fig. 4v). Since be-tween the stopping of the layer 224 at the retaining stop 47 and the lowering thereof for discharging the stack formed it is only necessary to withdraw the support members 43 and 44 laterally the new layer 225 remains a distance behind the stack moving out which permits the retaining pins 48 to be moved up again behind the discharged stack to enable the board 225 to replace the board 221 according to Figs. 4a a~ 41 as new first layer of a further stack. During the discharge of the stack from the stack support surface 30 sufficient time remains for the laterally withdrawn support members 43 and 44 to execute the loering and inward movement so that the lifting tables 26, 27 and 28, 29 and the slides 33, 34 and 35, 36 with the support members 41, 42, 43 and 44 have again reached the starting position according to Fig. 4a when the layer 225 strikes the again extended retaining pins 48. The cycle illustrated in Fig. 4 for the layers 221 to 224 is then repeated for the layers 225 to 228.

Thus, with the mode of operation according to Fig. 4 after introduction of a layer 22 the stack support surface 30 is freed in the quickest possible manner, i.e. by immediate lifting of the stopped layer 22 through the height h1, for the next layer 22 whilst the time required by the next layer 22 to pass from the start of the stack support surface 30 over the rear retaining stop 47 is utilised to move the other pair of support members 41, 42 or 43, 44, not required for supporting the layer 22 just lifted, to the readiness position for the next lifting movement of the new layer 22 beneath the stack support surface 30.

.

, ~7~8 Thus, the unavoidable time required by each L~er 22 for the inward movement, during which ~ecause of the motion of the moving-in layer 22 the latter cannot be lifted, is utilised optimally whereas in the embodiment according to Fig. 3 this time is idle time.

With the aid of the illustration of Fig. S it will be explained in detail hereinafter how a layer 22 is deposited on a raised following layer 22, choosing as example the bringing together of the layers 221 and 222 according to Figs. 4c and 4d, corresponding of course to Figs. 4n and 40, the riyht half of the diagrammatic views in Figs. 4c and 4d being shown, corresponding to the dot-dash circles V~ and Ve therein, to a larger scale in Fig.5 ~ith further details. Fig. 5a corresponds to the starting position for the converging according to Fig. 4c and Fig. 5e corresponds ~o the comp~eted depositing of the layer 221 on the layer 222 according to Fig. 4d.

In the example of embodiment of Fig. 5 it will be assumed that each layer 22 consists of three ad~acent mineral fibre boards 21 each extending over a third of the width of the layer 22. As apparent from Fig. 5a the support members 42 and 44 are so constructed that in the completely inwardly moved condition they extend into a region of the centre mineral fibre board 21 which gives adequate support in the lifting movement.
The support members 41, 42, 43 and 44 are made tapered towards their free adjacent ends, the lower edge being substantially hori20ntal so that the upper edge of the support members 41, 42, 43 and 44 slopes downwardly slightly from the ou-tside to the centre of the stack support surface 30. In the iilustration of Fig. 5a the upper support member 44 is at the heiyht h1 above the upper edge of the lower support member 42, reckoned .

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in each case from upper edqe to upper edge of the support members 42 and 44 in the untapered lateral outer region. The construction on the other side, i.e. the left side according to Fig. 5, of the stac~ing apparatus 11 is of course completely symmetrical.

In accordance with Fig. 5b the lower support men~er 42 first raises the layer 222 newly introduced onto the stack support surface 30 through the height h1 whilst the upper support member 44 with the layer 22 supported thereon moves upwardly through the smaller height h2. The travel h1 may for example be 90 mm whilst the travel h2 is only 50 mm. In this manner, during the common lifting movement of the support members 42 and 44 the layers 221 and 222 are already brought together as far as possible. The lateral withdrawal movement of the support member 44 may be started at this stage but this is not absolutely essential because the liftiny movement requires only a very small time of for example 0.2 s, comparatively negligible compared with the time of for example 1.5 s required for the withdrawal movement, and consequently the time required for the lifting movement need not always be utilised for the initiation of the withdrawal movement as well.

However, the withdrawal movement starts in any case following the lifting movement into the position according to Fig. 5b and is shown in detail in Figs. 5c, d and e. In the withdrawal movement the tip of the support member 44 first frees the laterally outer edqe of the centre mineral fibre board 21 of the layer 22' so that the la~er can drop onto the corresponding minexal fibre board 21 of the lower layer 222. The laterally outer mineral fibre hoard 21 of the layer 222 , ' ' ,.

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is held by a lateral stop 50 to be certain of pre-venting entrainmel~t thereo~ by friction at the support member 44.

In the course of the further withdrawal movement of the support member 44 the latter moves outwardly beyond the lonyitudinal centre of gravity of the mineral fibre board 21 so that the latter tilts inwardly downwardly according to the illustration of Fig. 5d and comes to bear with its inner edge on the corresponding mineral fibre board 21 of the lower layer 222. With the illustrated very thin mineral fibre boards 21 there is a dan~er that for instance by springing back at the stop 50 the inner ed~e of the laterally outer mineral fibre board 21 of the layer 221 could move over the outer edge of the centre mineral fibre board 21 of the layer 221 so that these two mineral fibre boards 21 wo~ld come to lie in the stack with their edges over each other.
This danger is however ~iminated because due to the tapered construction of the support member 42 (and of course the other support members) the inner tip of the support member 44 comes to lie at an appreciable distance above the inner area of the layer 222 disposed therebelow so that the laterally outer, upper mineral fibre board 21 executes a pronounced tilting ~ovem~nt in accordance with Fig. 5d. Since also during the tilting movement the mineral fibre board 21 is also drawn by friction by the support member 44 against the stop 50 the lateral outer mineral fibre board ~1 moves into the position according to Fig. Sd in which the outer edge thereof is raised and said board is drawn away from the centre board 21. Even with narrow tolerances in this manner a gap is formed between the adjacent edges of the mineral fibre boards 21 of the , .:

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7~S~3 layer 221 illustrated and this gap ensures that the inner edge of the outer mineral fibre board 21 drops down adjacent the outer edge of the centre mineral fibre board 21 and does not come to lie on said edge even if due to the small height or thickness of the layer 222 such a sliding over of the edges of the mineral fibre boards 21 were conceivable.

In the illustration of Fig. 5e the support member 44 is withdrawn in the manner also apparent from Fig. 4d laterally completely out of the stacking space 23 limited laterally by the stops 50. Due to the vibrations occurring the laterally outer mineral fibre board 21 can now bear flush against the centre mineral fibre board 21 or also remain in sliding contact with the stop 50.

In Fig. 6 a mode of operation corresponding in principle to Fig. 4 is illustrated of an embodiment of a stacking apparatus according to the invention modified compared with the embodiment according to Fig. 2. In the embodiment according to Fig. 6 four lifting means 26a, 27a, 28a and 29a are provided in the form of lifting tables similar to the lifting tables 26, 27, 28 and 29 of the Fig. 2 but these lifting tables form in each their own lifting means 26a, 27a, 28a and 29a because they are movakle up and down independently of each o~her. At the top of the lifting tables of the lower liting means 26 a and 27a slides 33a and 34a are again mounted with vertical spacers 37a and 38a on which fork-like support members 41a and 42a are mounted. Correspondingly, on the lifting tables of the upper lifting means 28a and 29a slides 35a and 36a are movable on which via - 3~ -.
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, vertical spacers 39a and 40a spaced beneath the lifting tables and the sl..ides 35a and 36a fork-like support members 43a and 49a are mounted. The support members 41a, 42a, 43a and 44a extend like the support members 41, 42, 43 and 44 in tile horizontal direction from each of the associated slides 33a, 34a, 35a and 36a in the direction towards the stack support surface 30 but whereas the support members 41, 42, 43 and 44 extend at the most over just less than half the width of the stack support surface 30, thus engaging below the layers 22 in pairs, the support men~ers 41a,42a, 43a, and 44a each have a length extending at least approximately over the entire width of the stack support surface so that a single support member 41a, 42a, 43a or 44a can lift a layer 22. The spacers 37a, 38a, 39a and 40a permit, like the spacers 37, 38, 39 and 40 according to Fig. 2, mutual interpassage of ~-the support members 41a and 43a and 42a and 44a, in gap alignment, on one side of the gap support surface.
Furthermore, in the embodiment according to Fig. 6 as well associated support members on both sides of the stack support surface 30 may be in alignment which in the embodiment according to Fig. 6 is the case with regard to the support members 41a and 44a on the one hand and 43a and 42a Oll the other. Whereas however in the embodiment according to Fig. 2 the aligning support members-41 and 42 and 43 and 44 respectively are relatively movable in the horizontal direction and for this reason do not come into contact because in their closest position a space remains between their tips, such a mutual contacting of the possibly aligning support members 41a and 44a and 43a and 42a is impossible because they are an invariable horizontal distance apart, i.e. are moved synchronously in the same sense in the horizontal direction Because of the greater . .

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length of the support members 41a, ~2a, 43a and ~4a the travels for the inward movement and withdrawal are of course correspondingly greater than in the case of the support members 41, 42, 43 and 44 which in production lines with a standard programme of relatively large widths may be made comparatively short because they need only project into the stacking space 23 enough to support the large-area mineral fibre boards 21 adequately and consequently particularly small inward and withdrawal travels result with a corresponding saving in time. In contrast, however, the embodiment of Fig. 6 has the advantage that a total of four lifting means 26a, 27a, 28a and 29a operate alternately and produce useful lifting movements so that the apparatus as a whole can run slower to obtain a desired cycle fre~uency.

In the illustration of Fig. 6a a first layer 221 has just run onto the stack support surface 30 and stopped by the rear retaining stop 47, not illustrated in detail.
All the support members 41a, 42a, 43a and 44a in this starting position are disposed at a vertical levei immediately beneath the stack support surface 30, the support members 41a and 42a being in the inward position beneath the stack support surface 30. This position corresponds substantially to the starting position as illustrated for the embodiment of the stacking apparatus 11 according to Fig. 2 in Figs. Qa and 41.
.
From the position according to Fig. 6a the layer 221 just entered is raised by the support member 41a into the position according to Fig. 6b through h1 50 that the stack support surface 30 is free for introduction of the next layer 222. In Fig. 6b the layer 222 is ,:, .
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illustratcd in its introduction position onto the stack support surface 30. This position corresponds substantially to the position according to Fig. 4c ancl 4n for the emho~ment of the stacking apparatus 11 according to Fig. 2.

In Fig. 6c an intermediate position during the subsequent lifting movement is illustrated in which the support member 42a is again raised by the amount h1 and thereby lifts the new layer 222 whilst the support member 41a thereabove with the layer 221 disposed thereon moves upwardly through the height h2 and laterally out of the gap between the layers 221 and 222 so that the layer 221 is deposited on the layer 222. -In Fig. 6c, as in the following Figs. 6e, 6g and 6i, the support member being withdrawn is shown already considerably retracted for clarity although in the course of the short lifting movement, even if the withdrawal movement begins then, only a short initial part of the considerably longer travel compared with the lifting travel is covered. The position according to Fig. 6c corresponds substantially to an intermediate position between Figs. 4c and 4d or 4n and 40 for the embodiment according to Fig. 2.

In the position according to Fig. 6d the lifting and withdrawal movements explained above in conjunction with Fig. 6c are concluded so that the support member 42a is at the height h1 above the stack support surface 30 whilst the support member 41a is laterally withdrawn from the gap between the layers 221 and 222 and is at the height h1 plus h2 above the stack support surface 30. During the withdrawal movement of the support member 41a in the manner apparent from Figs. 6a and 6c the support member moving horizontally synchronously therewith has moved into the region beneath the stack .
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:~: lS70~ii3 support surface 30. In the position according to Fig. 6d the stack support surfacc 30 is free for the entry of the following layer 223 which in Fig. 6b is shown already on the stack support surface 30.
The position according to Fig. 6d thus corresponds to the position according to Figs. 4e and 4b of the embodiment according to Fig. 2.

Fig. 6e again shows an intermediate position during the lifting movement which then follows of the support member 44a for lifting the newly introduced layer 223 and the withdrawal movement of the support member 42a from the gap between the layer 223 and the partial stack comprising the layers 221 and 222, and in the course of the withdrawal movement of the support member 42a the support member 43a running in the horizontal direction synchronously therewith moves beneath the stack support surface. This time is then available to the support member 41a which according to Fig. 6d is moved laterally out of the region of the stack support surface 30 for lowering through the height h1 plus h2 in preparation for the inward movement thereof beneath the stack support surface 30.

The position according to Fig. 6g corresponds substan-tially to an intermediate position between the Figs.
4f and 4g of the embodiment according to Fig. 2. The position corresponding to Fig. 4g is reached in Fig. 6f in which the support member 44a has reached the lift height h1 and supports the partial stack comprising the layers 221, 222 and 223 whilst the new layer 224 corres-ponding to the position according to Figs. 4h and 4s according to Fig. 2 is already running onto the stack support surface 30. The support member 42a is withdrawn laterally completely from the region of the stack sup-port surface 30 and the gap above the layer 223 and has ;.

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7~;~8 deposited the layers 221 anc1 222 0l1 the layer 223.
Synchronously with the withdrawal mov~ment of the support member 42a the support member 43a is moved beneath the stack support surface 30 and is avail-able for the lifting of the new layer 224 as soon as the latter has been stopped at the rear retaining stop 47. The support member 41a has reached its lower end position in the plane beneath the stack support surface 30 and is ready to be moved beneath the stack support surface 30.

Fig. 6g again shows an intermediate position in which the new layer 224 is being lifted by the support mem-ber 43a while the support member 44a moves upwardly and is thereby withdrawn laterally from the gap beneath the new layer 224. In the course of the lateral with-drawal movement of the support member 44a the horizon-tally synchronously running support member 41a moves beneath the stack support surface 30. According to Fig. 6h the end position of the movement illustrated in Fig. 6g has been reached, the support member 44a being completely withdrawn from the region of the stack support surface 30 and at the height h1+h2 while the support member 43a has lifted the new layer 22 through the height h1 50 that the stack support surface 30 is again free for the introduction of a new layer 225 which in Fig. 6h is shown already running on to the stack support surface 30. The sup~port member 41a has heen moved completely beneath the stack support surface 30 and is available for a liftin~ of the incoming new layer 225 as soon as the latter has stopped at the rear retainin~ stop 47. Corres~ondingly, the support member 44a running synchronously in the horizontal direction '" `

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, has been removed completely laterally from the stack region and is at the heic3l1t h1~h2.

The lifting movement of the new layer 225 now takes place according to Fig. 6i by raising the sup~ort mem-ber 41a while the support member 43a supporting the previously formed partial stack moves upwardly and is withdrawn laterally from the stack. In the course of this lateral witharawal movement of the support mem-ber 43a the support member 42a moves beneath the stack support surface 30 and the support member 44a has been Iowëred by the height h1-~h2 beneath the plane of the stack support sur~ace 30.

In the position according to Fig. 6j the layer 225 is raised through the height h1 so that the stack support surface 30 is again free for the entrance of the next layer 226 which is already running on to the stack i~
support surface 30. The support member 43a has been com-pletely withdrawn from the stack and correspondingly the support member 42a completely moved beneath the stack support surface 30.

It is assumed that in the present case six layers 22 are to form a finished stack. The illustration of Fig.
6j then corresponds to that according to Fiy. 4h and 4s or 4i and 4t of the embodiment according to Fig. 2 with the difference that the previously formed partial stack supported by the raised suppor-t member 41a includes five layers 22 and not three. If then according to Fiy. 6k the liftinq movement of the support member 42a actually ready for lifting the layer 226 does not take place and only the support member 41a beneath the pre-viously formed partial stack of five layers 22 is .

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withdrawl1 laterally and deposi~ said ]ayers on the new layer 22G, the support member ~4a necessarily also being moved beneath thc stack support face 30, then according to the illustration of Figs. 4j and 4u for the embodiment according to Fig. 2 the finished stack consisting of six layers 22 in this case lies on the stack support surface 30 and after lowering of the rear retaining stop 47 can run onto the discharge belt 20 to make room for the next layer(227)not illustrated in detail which like the layer 221 according to Fig. 6a forms the first layer for a new stack oE six layers 22 and strikes the again raised retaining stop 47 after the finished stack has been discharged. Simultaneously with the withdrawal. movement of the support member 41a the lowering of the support member 43a previously with-drawn according to Fig. 6i takes place into ~a~'`pIane beneath the stack support surface 30 so that after the discharge of the stack comprising six layers 22 and resting on the stack support surface 30 according to Fig. 6k the two support members 42a and 44a are beneath the stack support surface 30 and ready for lifting whilst after the lowering of the support member 41a taking place substantially simultaneously with the : next lifting movement the two support members 41a and 43a are adjacent the stack support surface 30 but also beneath the plane thereof. This is a position of the support members again corresponding to Fi~. 6a from which in a readily apparent manner the working step sequence according to Fig. 6a to 6k can be carried out to form the next step. When the first layer (227)o~the following stack is raised by the support member 42a, if desired synchronously a horizontal movement of the horizon~ally synchronously running support members 41a ~ 41 -'~ : , ' ; . ' , ~ ,:'' .

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~iS~ S8 and 44a can take p]ace in the illustration according to Fig. 6k to the right in order to reach the start-ing position according to Fig. 6a again. Alterna~ ;
tively, however, instead of the startinq position corresponding to Fig. 6a a starting position corres-ponding to Fig. 6k may be chosen because in each case two suppor~ members ,41a and 42a in the case according to the position of Fig. 6a and 42a and 44a in the case of the position according to Fig. 6k, are beneath the stack support surface 30 ready for a lifting movement and can thus immediately raise the first two layers (227) and (228) of the following stack. Since this is the only criterion for the starting position the positions according to Figs.
6a and 6k are equivalent as starting positions.

As the above explanations show in all the embodiments of the stacking apparatus 11 explained a cycle time of less than 2 s can be achieved as is necessary in accordance with the explanations with regard to Fig. 1 in order to continuously stack the mineral fibreboards 21 or their sheet arrays delivered on the production line therein. With the mode of operation according to Fig. 4 or 6 still shorter cycle times are possible because in advantageous manner each newly introduced layer 22 after meeting the rear retaining stop 47 can be lifted immediately with a time requirement of only about 0.2 s and the stack support surface 30 is then immediately available for entrance of a following layer 22 which can thus enter at a time interval of only slightly more than 0.2 s while the unavoidable time requirement for a complete introduction of the new layer 22 until the rear retaining stop 47 is ,~

.

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;~ ` . ` . ' , ' ~57~8 reached is used to prepare the support members of the stacking apparatus 11 for the lifting of the new layer 22 enterin~.

At least the individual fork-like support members 41, 42, 43 and 44 or 41a, 42a, 43a and 44a lying the greater distance in front of the retaining stop 47 can be detachably mounted on the correspon-ding slides 33, 34, 35 and 36 or 33a, 34a, 35a and 36a so that for a continuous production the front support members which are not required for suppor-ting the respective layer 22 over the length there-of can be removed. Apart from the saving in weight of the moving parts such front support members can also then not collide with the leading edge of a following new layer 22 so that the latter can enter the stacking apparatus 11 with the time interval actually required for the lifting movement after the rear edge of the preceding layer 22. Conversely, for a large-area longer mineral fibre plates 21 the utilizable stack length can be increased in that the rear edge projects somewhat opposite to the production direction according to the arrow 1 beyond the front side of the foremost supporting members as long as it is ensured that the supporting at the foremost support members in the production direction is in front of the centre of gravity of the rearmost- mineral fibre-board 21 of the array. In addition, for standard pro-grammes of large-area mineral fibreboards 21 the length of the support members 41, 42, 4~ and 44 as well as 41a, 42a, 43a and 44a can be shortened to a minimum ensuring a supporting of the centres of gravity of the mineral fibreboards 21 and with this shortening of the support members the .inward and withdrawal travels and thus the time required can also be reduced.

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Due to the minimum drop of ~he individual layers 22 when they are united with an introduced new layer 22 the stacking apparatus according to the invention achieves a controlled and trouble-free careful depo-siting of the previously formed partial stack on the new layer 22. By corresponding formation of the sup-port members ~1, 42, ~3 and 44 or 41a, 42a, 43a and 44a substantially according to the illustration of Figs. 2 to 6 excellent support of the individual layers is also ensured so that even mineral fibre-boards 21 of soft and thin material are not liable to be damaged in any way. In cooperation with the retaining belt 8 the stacking apparatus 11 according to the invention also ensures a maximum stacking capacity for individual mineral fibreboards 21 and board arrays previously ~ormed on the retaining belt 8. This ensures high productivity o~ the pro-duction line and in the manner outlined an infinitely variable adaptation can be made to different lengths of the mineral fibreboards 21. The aligned charging and discharging of the stacking space 23 of the stacking apparatus 11 ensures that not only in the course of formation of a stack but also after forma-tion of a finished stack no resetting time or the like is required which would lead to problems with a continuously operating production line and make neces-sary for instance a previous intermediate storing of the irst layers of a new stack. On the contrary, according to the invention the discharge of the finished stack takes place substantially in time with the cycle so that independently of the stack position reached each layer 22 can move onto the stack support surface 30 with the same ~requency and either be stacked on the previously formed partial stack or form .
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S7~i8 the first layer of a new stack. Since no slidinq mov~ment at al]. occurs between the layers 22 during the staekiny the apparatus 11 is particu-larly suitable for boards with poor sliding and stability properties. Furthermore, b~ards oE low density and porous or fibrous structure, in par-tieular mineral fibreboards 21, may be stacked without any problems because they are supported gently from below and no suckers or the like are required for the staeking. Moreovèr, the small drops permit rapid staeking of light layers parti-cularly since the greater part of the movement necessary for bringing the layers together is aehieved by a lifting movement and not by a drop-ping movement.

Finally, a particular advantage results from the fact that the retaining belt 8, the staek support J
surfaee 30 and the diseharge belt 20 are not only in alignment with eaeh other but also lie in a plane so that in the ease of failure of the staeking apparatus 11 the mineral fibreboards 21, possibly after previous array formation on the retaining belt 8, ean pass through the stationary s-taeking apparatus 11 without obstruetion and eonsequently a stacking apparatus 11 stationary in the case of trouble need not necessarily mean produetion stoppage; on the contrary, during sueh a failure the stac~ing can be conducted in emergency operation'by hand or the un-stac~ed boards may be intermediately stored in some other manner. This is of particular signifieanee for instance in the production of mineral fibreboards 21 whieh requires a eontinuous operation of the melting trough and eonsequently produetion interruptions ean result in high losses.
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As the above description shows the invention is not restricted to the embodiments illustrated, many modifications being possib]e without leaving the scope of the invention. Thus, for example, the sup-port members 41, 42, 43 and 44 as well as 41a, 42a, 43a and 44a may be given a different construction to obtain an optimum area support of the layers 22.
Also, details of the movement control of the support elements may differ provided the desired aim is still achieved. In this connection, for example, the syn-chronous control of the horizontal movement of the support members 41a and 44a on the one hand and 42a and 43a on the other hand may he dispensed with and all four sets of support members 41a, 42a, 43a and 44a according to Fig. 6 moved independently of each other if the support members 41a and 42a and 43a res-pectively are also offset with respect to each other.

: .

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Method of stacking stackable material, in particular mineral fibreboards in a production line, in superimposed layers of one or more articles, wherein the articles forming a new layer are introduced into a stacking space and there brought together with the previously introduced layers already forming a partial stack from the bottom thereof, the previous formed partial stack being held spaced above the entrance plane of the layers into the stacking space and after entering the stacking space the respective new layer being raised at least a height corresponding to the thickness of the layer to be stacked and characterized in that the previously formed partial stack is, at least at the beginning of the raising movement of the new layer, kept supported independ-ently of the new layer and is also raised concurrently with the new layer so as to maintain a vertical distance between the bottom of the partial stack and the upper surface of the new layer.

2. Method according to claim 1, characterized in that the previously formed partial stack is raised through a lesser height than the new layer.

3. Method according to claim 1 or 2, characterized in that the last new layer of the stack is left in the entrance plane and the partial stack is placed from above onto the last layer.

4. Method according to claim 1, characterized in that the finished stack is discharged on the side of the stacking space opposite the entrance side of the individual layer.

5. Apparatus for stacking stackable material, in parti-cular mineral fibreboards in a production line, in superimposed layers of one or more articles, comprising a) a plurality of lifting means for the layers of the articles for achieving the vertical displacement of the layers in formation of the stack, b) a stationary lower stack support surface, c) a stop disposed in the entrance direction of the layers behind the stacking space for aligned stopping of the respective new layer introduced and d) a conveying means for carrying away the finished stack, wherein each lifting means comprises at least one support member for the layers which is aligned at least approximately parallel to the stack support surface and which can be moved from the side beneath the stack and after the completed lifting can be withdrawn again from the stacking space, and which in the vertical direction is moveable relatively to the support member of one of the other lifting means, characterized in that the support members of one of the lifting means are mounted relatively moveable in a horizontal direction with respect to those of at least one of the other lifting means, that the support members of each lifting means during vertical movement pass through the support members of another lifting means lying on the same side of the stack space, and that the support members are formed as fork arms, the fork arms being offset to an extent permitting vertical mutual passage thereof with respect to the fork arms of another lifting means lying on the same side of the stacking space.

6. Apparatus according to claim 5, characterized in that two lifting means are provided and each lifting means comprises sets of support members disposed on both sides of the stacking space and synchronously driven, said members extending in each case over less than half the width of the stack support surface.

7. Apparatus according to claim 5, characterized in that four lifting means are provided which comprise sets of support members arranged in pairs on both sides of the stacking space which extend at least approximately over the entire width of the stack support surface.

8. Apparatus according to claim 7, characterized in that the support members of each two lifting means disposed on opposite sides of the stacking space have a constant horizontal distance apart to avoid mutual interpassage.

9. Apparatus according to claim 5, characterized in that the support members are mounted via spacers with ver-tical spacing at the bottom of upper bearing members and at the top of lower bearing members of the lifting means.

10. Apparatus according to claim 5, characterized in that the fork arms taper in the direction towards their free ends.

11. Apparatus according to claim 5, characterized in that the stack support surface aligns with the plane of an entrance path for the individual layers and the plane of a removal path for the finished stack.

12. Apparatus according to claim 11, characterized in that the entrance path and the removal path adjoin each other rectilinearly with interposed stack support surface.

13. A method of operating an apparatus for stacking stackable material, in particular mineral fibreboards in a production line to provide superimposed layers of one or more articles, said apparatus including first and second lifting means for the layers of articles for achieving the vertical displacement of the layers in the formation of the stack, a stationary lower stack support surface, a stop disposed in the entrance direction of the layers behind the stacking space for aligned stopping of the respective new layer introduced and a conveying means for carrying away the finished stack, wherein each lifting means comprises at least one support member for the layers which is aligned at least approximately parallel to the stack support surface and which can be moved from the side beneath the stack and after the completed lifting can be withdrawn again from the stacking space, and which in the vertical direction is moveable relatively to the support member of one of the other lifting means, the support members of one of the lifting means being mounted relatively moveable in a horizontal direction with respect to those of at least one of the other lifting means, the support members of each lifting means during vertical movement passing through the support members of another lifting means lying on the same side of the stack space, and the support members being formed as fork arms, the fork arms being offset to an extent permitting vertical mutual passage thereof with respect to the fork arms of another lifting means lying on the same side of the stacking space, said method characterized in a) that the support members of the first lifting means raise a first layer introduced onto the stationary stack support surface to a height permitting entrance of a second layer, b) that then the support members of the second lifting means raise the second layer after complete introduction thereof onto the stack support surface to a height permitting an entrance of a third layer, and the support members of the first lifting means raise the first layer further to permit the lifting movement of the second layer and are then moved for lateral withdrawal from the gap between the first and second layers, c) that the support members of the second lifting means hold the second layer at at least the height permitting the entrance of the third layer.

14. Method according to claim 13, characterized in d) that during the entrance of the third layer onto the stationary stack support surface the support members of the first lifting means after lateral withdrawal from the gap between the first and second layers are lowered and move inwardly again beneath the stack support surface, e) that the support members of the first lifting means raise the third layer after the complete introduction thereof onto the stack support surface to a height permitting an entrance of a fourth layer, and the support members of the second lifting means further raise the second layer for permitting the lifting movement of the third layer, and are then moved for lateral withdrawal from the gap between the first and the second layers, and f) that the support members of the first lifting means hold the third layer at at least the height permitting the entrance of the fourth layer.

15. Method according to claim 13, characterized in d) that during the introduction of the third layer onto the stationary stack support surface the support elements of the first lifting means are moved for lateral withdrawal from the gap between the first and second layers, e) that the support members of the third lifting means raise the third layer after complete introduction thereof onto the stack support surface to a height permitting entrance of the fourth layer, and the support members of the second means further raise the second layer for per-mitting the lifting movement of the third layer and are then moved for lateral withdrawal from the gap between the second and third layers, f) that the support members of the third lifting means hold the third layer at at least a height permitting the entrance of the fourth layer, g) that during the introduction of the fourth layer onto the stack support surface the support members of the second lifting means are moved for lateral withdrawal from the gap between the second and third layers have been later-ally withdrawn, h) that the support members of the fourth lifting means then raise the fourth layer after complete introduction thereof onto the stack support surface to a height permitting an entrance of a fifth layer, and the support members of the third lifting means further raise the third layer for permitting the lifting movement of the fourth layer and are then moved for lateral withdrawal from the gap between the third and fourth layers, i) that the support members of the fourth lifting means hold the fourth layer at at least the height permitting entrance of the fifth layer, j) that during the introduction of the fifth layer onto the stack support surface the support members of the third lifting means are moved for lateral withdrawal from the gap between the third and fourth layers, k) that the support members of the first lifting means after lateral removal from the gap between the first and second layers and after lowering during at least one of the working steps e to j are again inwardly moved beneath the stack support surface, l) that then the support members of the first lifting means raise the fifth layer after the complete introduction thereof onto the stack support surface to a height permitting entrance of a sixth layer, and the support members of the fourth lifting means further raise the fourth layer for permitting the lifting movement of the fifth layer and are then moved for lateral withdrawal from the gap between the fourth and fifth layers, and m) that the support members of the first lifting means hold the fifth layer at at least the height permitting the entrance of the sixth layer.

16. Method according to claim 13 wherein each said lifting means comprises sets of support members disposed on both sides of said stacking space characterized in that the support members of every two lifting means lying opposite each other across the stacking space are moved synchronously together in the horizontal direction to avoid mutual interpassage.

17. Method according to claim 13, characterized in that the layer intended to form the lowermost layer of the finished stack after complete introduction thereof onto the stack support surface remains on the latter and the partial stack formed thereabove is lowered onto the last layer, and that the support members of the lifting means serving to lift the penultimate layer are withdrawn later-ally from the gap between the last and penultimate layer.