Patent Publication Number: US-3880979-A

Title: Method and apparatus for pressing concrete panels

Description:
Hemingw ay [451 Apr. 29, 1975 1 1 METHOD AND APPARATUS FOR PRESSING CONCRETE PANELS [75] Inventor: Trevor Hemingway, Dronfield, near Sheffield, England [73] Assignee: Davy-Loewy Limited, Sheffield,  
 Yorkshire, England [22] Filed: Feb. 12, 1973 [21] Appl. No.: 331,613  
 Related US. Application Data [63] Continuation of Ser. No. 104.090, Jan. 5, 1971. abandoned, and a continuation-in-part of Ser. No. 704,715. Feb. 12, 1968, abandoned.  
 [30] Foreign Application Priority Data Feb. 15, 1967 United Kingdom 7198/67 [52] US. Cl. 264/333; 264/86; 264/336; 425/84; 425/410; 425/416; 425/423 [51] Int. Cl B28b 3/04; B28b 7/10 [58] Field of Search 264/319, 333, 336, 86,  
 [56] References Cited UNlTED STATES PATENTS 59.212 10/1866 Gregg 25/60 X 1,561,257 11/1925 Livemont 25/41 E X 1,699,017 1/1929 Poorc 25/41 E 1,993,047 3/1935 Westman 264/86 2,047,356 7/1936 Boyle 425/84 2,427,044 9/1947 Burns 25/84 UX 2,650,412 9/1953 Dubbs 264/87 2,781,570 2/1957 Seymour.... 425/177 X 2,926,412 3/1960 Stacy et a1. 25/84 X 3.153.833 10/1964 Jackson, Sr 25/101 X 3,577,610 5/1971 Margolin et al. 25/41 D X Primary ExaminerJan H. Silbaugh Allorney, Agent, or Firm-Brisebois &amp; Kruger [57] ABSTRACT zontal dimensions greater than those of the mold.  
 When the top of the mold walls engage the top platen. upward movement of the mold base only is continued to press the concrete between the top platen and the mold base.  
 12 Claims, 4 Drawing Figures SHEET 10F 2 PATENTEUAPR29 I975 QHR METHOD AND APPARATUS FOR PRESSING CONCRETE PANELS This is a continuation, of application Ser. No. 104,090, filed Jan. 5, 1974, now abandoned.  
  This invention relates to the molding of articles and is a continuation-in-part of my application Ser. No.  
 704,715, filed Feb. 12, 1968, now abandoned.  
  The invention is particularly, but not exclusively, concerned with the molding of concrete panels by placing a wet concrete mix in a mold and subjecting it to high pressure. The pressing action drives out the water of the mix leaving a green panel which is selfsupporting and which is sufficiently strong to be removed immediately from the mold. After a setting period, which is small compared with the setting periods normally associated with cast, but not pressed, panels, the panel is ready for use.  
  This method of pressing or molding lends itself to the fast production of panels and to the automation of concrete panel production; few molds are needed and space requirements are reduced, the stacking of the pressed panels occupying very much less space than the molds that would be needed in casting.  
  The Dettling et al. U.S. Pat. No. 3002247 patented Oct. 3, 1961, describes apparatus for forming concrete blocks by applying pressure to concrete in a mold box. As illustrated, the mold has a base secured permanently to the side walls and is raised for pressing by a hydraulic ram. A pair of pallets are placed in the mold, followed by a fill of concrete which is said to be levelled off to a fixed depth by a screed. Then the mold is further raised against a pressure platen which has outside dimensions to engage the mold walls but has parts which project into the mold as the mold is raised and which therefore compress the concrete.  
  The construction of the Dettling et al apparatus is such that only a fixed size productcan be molded, no alteration of the dimensions of the products being possible without effective replacement of both the mold and the pressure platen. Moreover, with a given mold and platen, no variation is possible in the thickness of the pressed products or in the degree of compression: the volume of concrete in the mold is fixed by the screed action while the penetration of the platen into the mold is fixed by the engagement of the mold walls with the platen and the size of the projecting parts of the platen. While the Dettling et al. construction is possibly useful for molding a standard sized and shaped product at a limited rate, it is altogether inapplicable to a production unit with such a high production rate that, for proper utilisation of the plant, products of different sizes must be molded in batches, each of which may consist of a high number of products of the same size.  
  In the mold of the present invention, the base and walls are not fixed together immovably; instead, relative movement is possible between the base and the tops of the side walls. This mould co-operates with a pressing platen which has greater horizontal dimensions than those of the largest mold to be used and which has a substantially planar underface with no downwardly projecting parts. When an appropriate amount of material, e.g. concrete, has been inserted in the mold, the mold is raised until the walls engage against the pressing platen. Unlike Dettling et al., however, the pressing operation is not then complete; instead, relative movement between the platen and the mold base only is continued, relative movement between the walls and platen being prevented by their mutual engagement. This subsequent movement of the base relative to the platen causes compression of the mold contents regardless of the volume of the contents.  
  With a pressing platen larger in horizontal dimensions than the maximum size of mold to be employed and with a planar underface, modification of the equipment for various sizes of panel is possible, no alteration of the pressing platen being required and modification of only the mold being needed. The mold construction may be such that changes in the mold dimensions are relatively easily achieved.  
  The pressing platen may be fixed both vertically and horizontally, the mold being mounted to move in two directions. Firstly, the mold can be moved vertically for the pressing operation. Secondly, the mold may be moved horizontally from a filling position displaced from the platen to a second position immediately below the platen. Then, the sequence of operation is (I) fill the mold when in the filling position (2) run the mold under the fixed platen, on rails for example (3) press (4) strip the pressed panel from the mold and return the mold to the filling position.  
  The invention is illustrated by the following description of a concrete press and its mode of operation, reference being made to the accompanying drawings, in which FIG. 1 is a plan view of the press mold,  
  FIG. 2 is a vertical section on the line lI-Il of FIG.  
  FIG. 3 is a section on the line IIl--lIl of FIG. 1, and FIG. 4 is a view similar to FIG. 3, but showing the mold walls retracted for stripping.  
  The molding press illustrated in the drawings has a fixed perforated pressing platen 12 and a mold which is moved upwardly to press the contained concrete against the platen 12.  
  The mold has a carriage constituted by a pair of cross beams 13, 14 each of which at each end has a rail wheel bogey 15, the wheels of which run on rails indicated at 16. Each bogey has an upwardly extending guide rod 17 projecting into an opening in the cross beam 13 or 14 and is spring mounted by virtue of a spring 18 interposed between the bogey and an annular shoulder formed in the ends of the beams 13, 14.  
  The two cross beams 13, 14 are coupled by a pair of side beams 20, 21, which constitute one pair of opposite side walls of the mold. These side beams are of fixed length and the ends drop into notches formed at intervals along the length of the cross beams 13, 14: the notches are arranged symmetrically at each side of the centers of the beams 13, 14, so that any of a number of different separations can be chosen for the side beams 20, 21.  
  The other pair of opposite walls of the mold are constituted by a pair of cross beams 22, 23, there being a pair of such beams for each possible mold width. The beams 22, 23 can be attached to the side beams 20, 21 again at a number of different positions giving selected separations and hence selected mold lengths. Forthis purpose, the cross beams 20, 21 are slotted at intervals, one such slot being indicated in FIG. 3. Each end of the cross beams 22, 23 has a laterally and upwardly extending tongue 25, the upwardly extending part of which passes through a slot in a cross plate 26 and is held in position by a wedge 27 forced into a hole in the tongue and overlying the plate 26.  
  Each of the cross beams 22, 23 is formed with a shoulder 28 formed on its inner face and extending the full length of the beam. These shoulders 28 normally support a mold base 30 which has an upper surface constituted by a perforated plate 31. The mold base 30 is however capable of vertical movement off the shoulders 28 and relative to the mold walls 20-23. Packers 32 may be placed on the shoulder 28, in order to adjust the depth of plate 31 below the tops of the beams 20-23, and hence the depth of the mold. There may be a separate mold base 30 for each size of mold obtainable by adjustment of the beams 20-23, or there may be a single mold base which is adjusted in size to the required mold shape by insertion or removal of plate sections as required Below the platen 12 and beneath the level of the mold base 30, when moved on the rails 16, there is a series of pressing rams 33, each having a cover 34 to protect it from concrete spilt from the mold and water passing through the lower perforated plate 31. Similarly, there is a series of less powerful rams 35 located below the positions of the side beams 20 and each carrying a stripping head 36. The beams 20, 21 carry catcher plates 37 which extend downwardly at the sides of the stripper heads and then have a hooked portion extending under the stripper heads. Lastly, each side beam 20, 21 has a number of spring-loaded plungers 38, one of which is shown in FIG. 4, and which are urged into the path of the mold base 30. The mold base has cut-aways 40 aligned with the projecting ends of the plungers 38.  
 The operation of the molding press is as follows:  
  The mold is initially run on the rails 16 into a filling position displaced from the platen 12. It is then adjusted to the size of panel required to be pressed, the ends of the side beams 20, 21 being bolted to the crossbeams l3, 14 when the selected positions have been achieved. While the mold is in the filling position distant from the platen 12, the mold base 31 is covered with a filter sheet of porous material, the mold cavity 41 is filled with concrete, and the upper surface of the concrete is also covered with a filter sheet of porous material. The mold is then run in on its rails 16 into its operating or pressing position between the platen 12 and the rams 33. In this position, the lifting rams 35 are first operated to lift the entire mold structure up against the platen 12; during this movement, the bogeys 15 are left behind on their rails 16, the guide rods 17 sliding in their openings in the beams 13, 14.  
  Next, the main pressing rams 33 are actuated to press the mold base 30 upwardly; since the mold walls 20-23 are held against movement by engagement with the platen l2 and since the mold base and plate 31 are movable vertically relative to the sides of the mold, the concrete filling is pressed against the platen 12 to drive out the included water through the filter sheets, and to compact the concrete.  
  When the pressing operation is completed, the mold base 30 and hence the concrete are held in position by the rams 33 and the lifting rams 35 are withdrawn, causing, by virtue of the catcher plates 37, the lowering of the mold walls 20-23 and the attached cross plates l3, 14. During the downward movement, the beams l3, 14 are again placed on the bogeys l5 and towards the end of the downward movement, the spring loaded plungers 38 are forced inwardly into the recesses formed by the cut-aways 40. When the beams 13, 14 are in their fully lowered position, there are clearances between the plungers and the tops of the cut-aways 40, as indicated in FIG. 4.  
  The main rams 33 are next lowered, with the result that the mold base 30 and the pressed concrete panel which is indicated at 42 fall through the distance of the clearances and is brought to rest by the plungers 38; in this way, the concrete panel 42 is released from the platen 12; however, the panel 42 is still positioned above the level of the beams 20, 23 and can be removed from the mold with ease. Lastly, the mold is run out of the press on the rails 16 for removal of the panel 42.  
  After the panel 42 has been removed for curing, the plungers 38 are withdrawn, allowing the mold base to fall until it is brought to rest by the shoulders 28. Thereupon, the cycle can be recommenced by the filling of the mold with a fresh charge of concrete. The spring 18 reduces shock on the structure during this filling operation.  
  In place of the construction illustrated having two sets of lifting rams 35 and 33 for lifting respectively the entire mold, and the mold base only, the construction described in application Ser. No. 737,780 filed June 17, 1968, now abandoned, may be utilised. In the latter construction, the mold walls are carried by the mold base but are telescopic or collapsible in height; a single set of rams, which act on the base may now be used, the entire mold with the extended side walls being first raised until the tops of the walls engage the top platen 12. Then further movement of the base by the rams is accompanied by telescoping or collapsing of the mold walls, the separation between the mold base, on the one hand, and the top platen and the top of the walls, on the other hand, being decreased as before to cause compression of the concrete within the mold.  
 What is claimed is:  
  1. A process for molding a concrete panel comprising the steps of inserting a wet concrete mix into an open mold having mold walls and a mold base which is vertically movable relative to said mold walls when said mold is in a first filling position,  
 moving said mold horizontally to a pressing position vertically below a fixed horizontal platen,  
 raising said mold bodily until said mold walls are brought into contact with said platen,  
 then raising only said mold base to effect compression of said mix,  
 stripping the resulting molded panel from said mold,  
 and removing said panel.  
  2. A process for making molded panels from a settable cementitious comprising the steps of a. inserting said material at a filling position into an open mold having a base and upstanding mold walls, the horizontal dimensions of said mold being adjustable up to predetermined maximum dimensions b. moving said mold substantially horizontally from said filling position to a pressing position in which said mold is disposed beneath a fixed horizontal platen having horizontal dimensions exceeding said predetermined maximum dimensions and having a substantially flat underface free from downardly projecting parts;  
 c. moving said mold upwardly until said mold walls contact said platen underface and continuing upward movement of said base to compress the contained material against said platen;  
 d. lowering said mold from said platen,  
 e. moving said mold horizontally from said pressing but unset position,  
 f. removing the pressing but unset material from the mold, and  
 g. allowing said material to set.  
  3. A process as claimed in claim 1 in which said base is covered with a filter sheet of porous material before said settable material is introduced.  
 4. A molding press for molding panels comprising a. a stationary constantly horizontal platen having a substantially flat underface free from downwardly projecting parts;  
 b. a mold having upstanding side walls and a perforated base;  
 c. means for moving said mold horizontally between a pressing position beneath said platen and a filling position which is remote from said platen and at which said mold is filled with panel-making material; and  
 d. power means at said pressing position and acting on at least said mold base for first vertically moving said mold to bring said mold walls into engagement with said underface of said platen and the effecting further movement of said base towards said platen to cause said material in said mold to be compressed;  
 e. the horizontal dimensions of said mold being adjustable up to predetermined maximum dimensions;  
 f. and said platen having horizontal dimensions exceeding said predetermined maximum dimensions.  
  5. A molding press according to claim 4 in which said power means include first power means for raising said mold bodily and second power means for raising said mold base relative to said mold walls.  
  6. A molding press according to claim 5 in which said first power means are operable, subsequent to pressing, to lower said mold walls while said second power means support said base against movement, whereby said mold is stripped.  
 7. A molding press according to claim 4 in which said mold base is normally carried by said mold walls but is movable vertically within said mold walls.  
 8. A molding press according to claim 4 in which said mold includes wheels on which said walls are detachably mounted to facilitate movement between said filling and pressing positions,  
 said wheels being detached from said walls when said mold is raised by said power means.  
  9. A molding press according to claim 4 in which said mold walls are horizontally movable to occupy any one of a plurality of fixed positions in which they are prevented from further horizontal movement during pressing, thereby permitting changes in the horizontal dimensions of said mold up to said predetermined, maximum dimensions.  
 10. A molding press according to claim 9 in which said mold includes a support and adjustable mounting means on said support for mounting a first opposite pair of said mold walls at an adjustable separation,  
 the second opposite pair of said mold walls being carried by said first pair at an adjustable separation.  
 11. A molding press according to claim 10 in which said mold base is supported, prior to pressing, by said second pair of mold walls.  
 12. A molding press according to claim 11 in which said power means comprise a first set of hydraulic rams acting on said second pair of mold walls, and a second set of hydraulic rams acting on said mold base.