Device for wet-forming cardboard sheets into corrugated cardboard plates
United States Patent [1 1 Herr 1 1 DEVICE FOR WET-FORMING CARDBOARD SHEETS INTO CORRUGATED CARDBOARD PLATES [75] Inventor: Alfons Karl Herr, Karlsruhe.  
 Germany [73] Assignee: Elda AG, Glarus. Switzerland 122] Filed: June 7, 1973 [21] Appl. No.: 367,710  
 (30] Foreign Application Priority Data June 8. 1972 Germany 2227824 {52] US. Cl. 425/370; 93/1 R; 93/1 WZ [51] Int. Cl B3&#34; 1/36 [58] Field of Search 93/1 R, 1 W2. 1 H;  
 [56] References Cited UNITED STATES PATENTS 2.513.777 7/1950 Andr 425/371 X 1 1 Apr. s, 1975 3.032.452 5/1962 Magnaguagno 425/370 X 3.157.551 11/1964 Grandozid 425/371 X 3.369.955 2/1968 Rudlotf 425/370 3.792.952 2/1974 Hamon 425/371 X FOREIGN PATENTS OR APPLICATIONS 824.755 12/1959 United Kingdom 425/370 Primary E.raminerRoy Lake Assistant Examiner.1ames F. Coan Attorney, Agent, or Firm-Walter Becker {5 7] ABSTRACT A device for wet-forming cardboard sheets into corrugated cardboard plates which includes a charging device for charging cardboard sheets onto conveying means which feed the cardboard sheets in wet condition to a non-heated corrugating device for corrugating the received cardboard sheets into corrugated cardboard plates and discharges the same to drying means through which they are passed by a roller equipped supporting chain conveyor.  
 7 Claims, 1 Drawing Figure DEVICE FOR WET-FORMING CARDBOARD SHEETS lNTO CORRUGATED CARDBOARD PLATES The present invention relates to a device for wet deforming cardboard sheets withdrawn from a board machine, to corrugated cardboard plates.  
  Cardboard plates are according to the state of the art prior to the present invention manufactured in such a way that dried cardboard sheets withdrawn from a board machine are humidified again and are then conveyed to a corrugating device. This corrugating device consists primarily ofa pair of rollers which in the manner of gears mesh with each other and are heated to a temperature of from approximately 300 C. to 350 c. This pair of rollers burn, so to speak, the corrugation into the material under the influence of pressure and great heat. This corrugating device may also be employed for deforming a cardboard strip withdrawn from a Fourdrinier machine in which instance, however, as a rule a plurality of such roller pairs have to be employed.  
  In view of the great proportion of inorganic fiber material of different origin and quality, cardboard is not a homogenious substance. Consequently, this material offers different deforming resistance against the deformation which fact would require an adaptation of the deforming forces namely, pressure and heat.  
  With first dried and then again humidified cardboard sheets withdrawn from a board machine, there is to be added in this connection the different water absorption capability so that even within one and the same cardboard sheet, different deforming resistances may occur which would have to be taken into consideration in a corresponding manner. In reality, the heretofore known heated deforming tools, due to their high weight and great mass do not, however, follow these different conditions so fast that the profile of the corrugated plate after the deforming of the individual cardboard sheets will not be uniform and that therefore during the production any considerable amount of waste occurs.  
  An improvement could be obtained by first humidifying the dried cardboard sheets completely up to a humidity of approximately This, however, is generally not possible in view of the different water absorption capability. It is also to be taken into consideration that when making such corrugated plates in completely wet condition, the binding forces of the cardboard sheet and of the cardboard web withdrawn from the Fourdrinier machine are relatively low so that the pressure cannot be at will increased by the deforming tools.  
  Since, however, the influence of heat is limited by the at least superficial horn-like hardening of the material, it would be necessary serially to arrange a considerable number of such deforming tools in order to obtain an at least halfway stable corrugation and in order to dry the cardboard sheets or cardboard web under the influence of these tools. The high rate of waste as well as the high costs of investment, especially with the corrugated plate manufacture from a Fourdrinier machine, greatly increase the cost of the final product.  
  Aside from the nomhomogeneity of the material to be deformed, a further factor is to be mentioned which acts against the formation of a stable corrugation. Cardboard sheets obtain their shape stability during the first drying of the fiber connection, in other words, during the manufacture of flat cardboard sheets. In this way, there is already a certain preload present in the cardboard sheets so that first flat dried and thereafter deformed cardboards always have the tendency to return to their original shape. This tendency is noticeable in particular when such cardboard sheets become moist, and inasmuch as this absorption of humidity cannot be excluded, even with post-bitumenized corrugated cardboard plates, a first dried and thereafter deformed cardboard will have the tendency to counteract the previous deformation. Thus, corrugated cardboard plates of this type are not shaped stable. The corrugation becomes flatter and flatter and has the tendency to return to its original shape, that means the flat shape of the original cardboard sheet.  
  To overcome this drawback, it has been suggested according to my co-pending application, filed on even date with the present case, to withdraw the cardboard sheets from a board machine (Rundsieb- Kartonmaschine), and to corrugate the cardboard sheets in still humid condition with a humidity of at least 40% so that the longitudinal direction of the corrugation will be parallel to the main fiber direction of the cardboard. This corrugation in the main fiber direction of the cardboard has the advantage that the deformation resistance is extremely small so that no high pressure forces are required for the deformation. If the material is simultaneously dried, it will also in this corrugated shape be preloaded. This corrugated shape is thus the original shape for such corrugated plates so that returning forces to a flat form can no longer occur. If, therefore, cardboard sheets withdrawn from a board machine are deformed according to this method by means of deforming tools known per se, the waste is considerably reduced over heretofore known manufacturing processes of the type involved because the material has a considerably higher tolerance width with regard to the effect of pressure and heat. However, also with this method, a plurality of such deforming tools have successively to be employed in order to obtain a proper drying of the cardboard.  
  it is, therefore, an object of the present invention further to improve the method of my above mentioned copending application in order to eliminate the necessity that a plurality of heated deforming tools have to be arranged one behind the other.  
  This object and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing diagrammatically illustrating a deforming device according to the present invention.  
  The deforming device according to the present invention for deforming cardboard sheets withdrawn from a board machine, to corrugated cardboard plates, is characterized primarily by arranging directly adjacent to the board machine and one after another, a transverse runoff (Quer-Ablauf) known per se, a non-heated corrugating device, and a passage drier with roller supporting belt. The spacing of the rollers of the roller supporting belt corresponds to the distance between the individual corrugations. The corrugating device consists primarily of the roller supporting belt which passes through the passage drier, and a form roller belt engaging the roller supporting belt. Both belts are formed of tubes of the same diameter which tubes are linked on both sides to the elements of the driving chains, and the tubes have at least the length of one cardboard sheet. This corrugating device at the same time forms the inlet into the passage drier so that directly during the corrugating operation, the drying of the material starts. Thus, in contrast to heretofore known devices of the type involved, the deforming tools are no longer heated and the cardboard web is no longer within the deforming tools dried by the heat emanated from these tools. Instead, the cardboard sheets are cold corrugated and are directly subsequently conveyed to a transit drier. This method is particularly applicable when the cardboard sheets are so corrugated that the longitudinal direction of the corrugation is parallel to the main fiber direction, because in such an instance, the occurring reversing torques are rather low.  
  With this type of drying. the material is treated very carefully. and the humidity is gradually and uniformly withdrawn from the web of material. In addition to this withdrawal of humidity, with the increase in the binding forces, the corrugated cardboard is subjected to a preload which results in the tendency to retain this corrugated shape. A flattening of the corrugation is therefore no longer to be feared.  
  By effecting the drying in a passage drier, not only will the above mentioned advantages be realized and local overheating will be excluded, but also the rather costly heating of the deforming tools will be avoided which in turn greatly reduces the manufacturing costs. Furthermore, the danger of horn-like hardening or even of burning the material and thus a reduced suction ability for the later impregnation, as well as the danger of weakening the material texture especially in the valley of the corrugations will be avoided.  
  With the device according to the invention, the oncoming cardboard sheet is through the transverse runoff conveyed to the corrugating device in such a way that the main fiber direction will be located transverse to the transporting direction, Inasmuch as in this direction also the strength of the cardboard web is less, it is suggested that ahead of the inlet of the corrugating device. over a distance of from one-third to one-half of the width of the cardboard sheet in transporting direc tion, the idling rollers supporting the cardboard sheets are provided. Furthermore. it is suggested that the feeding speed of the feeding transporting device which feeds the cardboard sheets in spaced relationship to each other, is slightly less than the withdrawal speed of the form-transport belts of the corrugating device. This brings about that the material will slightly back up in front of the corrugating device so that the corrugating device comprising the roller supporting belt and the form roller belt does not have to pull the material whereby it could be weakened.  
  Advantageously. as feeding transporting device. a &#39;oller conveyor is employed so that when too great a nackup occurs ahead ofthe corrugating device, the ma- :erial will be able to slip on the transport rollers. It is 1ISO possible as feeding transporting device to employ 2 roller pair and to feed the material in a definite way .0 the corrugating device in such a manner that aside &#39;rom a last residual portion, always a slight pressure in he transporting direction will be exerted onto the web be shaped. This roller pair may also at the same time terve for embossing the cardboard sheets.  
  Within the corrugating device, which means between he roller supporting belt and the form roller belt, the naterial is then corrugated and is also during the drying )peration carried by the roller supporting belt. Inasnuch as during the drying operation, the binding forces inherent to the material become effective very quickly, the upper form roller belt need not be passed entirely through the passage drier. Nevertheless, it is suggested to provide an upper holding belt adjacent to the form roller belt in order to avoid changes in position of the corrugated cardboard sheets during the transport thereof through the passage drier and to avoid a warping of the drying corrugated cardboard plates. In this way, it will also be assured, especially when the individual rollers of the roller supporting belt are rotatable about their longitudinal axis, that the shrinkage occurring during the drying of the cardboard sheets will be reflected merely in a decrease of the height of the cor rugation but not in a change in the distance between the corrugated portions, The reduction in the height of the corrugation may, however, be eliminated without difficulties according to the present invention by selecting the depth over which the form roller belt engages the supporting belt greater so that this engaging depth will be adjustable. In this way, it will be possible without difficulties to take into consideration the shrinkage of different or differently thick material.  
  Referring now to the drawing in detail, the cardboard sheets 2 placed upon the sliding rails 5 of a transverse runoff, are by lowering the sliding rails 5 conveyed to a roller conveyor 3 in such a way that its main fiber di rection extends transverse to the transport direction 4 of the roller conveyor 3. Adjacent the roller conveyor 3 there are provided idling rollers 6 which support the cardboard sheets 2 and on which the cardboard sheets 2 are displaced toward a corrugating device 7. The corrugating device 7 is formed by a lower roller conveyor belt 8 and a form roller belt 9 which is arranged above the belt 8 and engages the latter. This corrugating device simultaneously forms the inlet into a passage drier I0 and conveys the undulated cardboard sheets at a speed 14 which is slightly less than the feeding speed 4. This corrugating device feeds the corrugated cardboard sheets through a passage drier l0.  
  Ifinstead of the feeding roller conveyor 3 a roller pair is provided which feeds the cardboard sheets 2 to the corrugating device, the displacement of the cardboard sheets may each time be so effected that the corrugation is always precisely at a desired spot for instance, starts at half the height of the corrugation. Moreover, in this way, it is possible to feed the material always at precisely defined pressure toward the corrugating device.  
  It is, of course, to be understood that the present invention is, by no means, limited to the specific showing in the drawing but also comprises any modifications within the scope of the appended claims.  
 What I claim is:  
  1. An apparatus for wet-forming cardboard sheets into corrugated cardboard plates, which includes: a cold forming corrugating means for receiving wet cardboard sheets and corrugating same, conveying means for conveying cardboard sheets to said corrugating means to be corrugated thereby, charging means ar ranged adjacent said conveying means and operable to receive cardboard sheets and depositing same onto said conveying means, and drying means extending around said corrugating means for drying corrugated card board plates formed by said corrugating means, said corrugating means defining the inlet of said drying means, said conveying means including idling roller means arranged ahead of said inlet when looking in the direction in which plane cardboard sheets are to be fed to said corrugating means, and said idling roller means being spaced from said inlet by a distance equalling from one-third to one-half of the width of the respective individual cardboard sheet.  
  2. An apparatus according to claim 1. in which said corrugating means includes an endless conveyor link chain with rollers and an endless shaping link chain with rollers. the rollers of both chains being formed by tubular members of the same diameter and being linked to the links of the pertaining chain, and means for driving said chains in synchronism with each other with the rollers of one chain offset to the rollers of the other chain by half the distance between each two successive rollers of the same chain.  
  3. An apparatus according to claim 2, in which the tubular members have a length equalling at least the length of a cardboard sheet to be corrugated.  
 4. An apparatus according to claim 2, in which said tubular members are rotatable about their longitudinal axes.  
  5. An apparatus according to claim 2, which includes a holding chain similar to said shaping link chain, said holding chain being arranged past said shaping link chain when looking in the direction of movement of the adjacent chain sections of said shaping link chain and said conveyor link chain and being located above the latter for cooperation therewith.  
  6. An apparatus according to claim I, which includes driving means operatively connected to said conveying means for driving the latter so as to feed the respective cardboard sheets in spaced relationship to each other to said corrugating means at a speed slightly higher than the speed at which said corrugating means discharges corrugated cardboard plates.  
 7. An apparatus according to claim 1. in which said conveying means includes a roller conveyor.