US 2649124 A
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A. c. MERRON 2,649,124
MANUFACTURE OF BARREL-S AND THE LIKE Filed Aug. 25, 1949 Aug. 18, 1953 2 Sheets-Sheet 1 //V Vf N 7 0/? 4/27/40 Cj ri/ Merron Aug. 18, 1953 A. c. MERRON MANUFACTURE OF BARRELS AND THE LIKE Filed Aug. 25, 1949 2 Sheets-Sheet 2 //vl//v7o/2.
Ar/Yrur Cy/v/ Merron fig 4.
BY ZyM A TTOPNEY.
Patented Aug. 18,, 1953 Arthur Cyrili;Merron, Twickenham, England.
Application August 25, 1949, SerialNo. 112,301v In GreatBritain August "30, 1948' This invention relates to the production of bodies of compound or intrinsic curvature.
The invention is applicable to the manufacture of casks or barrels, boat hulls, aircraft or urn-iture components, or other articles whose surfaces are of compound curvature.
According to the invention the bodies are made by assembling a plurality of substantially straight wooden core strips laterally coated with adhesive in lateralj-ux-taposition, subjecting the assembly to-pressure norm-alto its plane to give it thewholeof the required longitudinal and transverse curvatures whilst applying pressure laterally to the strips at least at the line or lines where the assembly has the greatest tendency to spread under the resistance of the strips to lateral bending thereby pressing the strips into lateral contact over their whole lengths, and maintaining the pressure until theadhesive has set. In effect, though in general each strip will be-bent'both longitudinally and laterally, insofar as its width is not substantially greater than its thickness, it willnot be-stressed substantially more highly than if it weregiven a' curvature of the same value lying in a single plane, whereas if it is attempted to give a widepleceof wood of' the-same thickness a compound curvature, in many cases the material would break, while if this did not happen the deformation would involve stresses of an altogether different order. Consideration will show that the strips willnaturally tend to set themselves during bending along geodetic lines or what-'may be called the lines of longitude of the form being aimed at; and the resistance of the strips to lateral bending will give them a tendency to spread apart at regions depending on the'form being aimed at; Consequently if lateral pressure is applied only at, the regions of maximum spread this will suffi'ce to press the assembly together'laterally over the'whole length of'the strips, and'the strips in general will be bent laterally by the lateral pressure as well as longitudinally by the pressure normal to the plane of the assembly and so normal to the thickness of the strips.
The structure above" described consists only of the'strips, adhesively secured together in the-desired conformation. For some'purposes this will sufiice. But for many purposes" the structure is not sufficiently stable and has other disadvantages: These may be overcome'byproviding the strip structure with a skin sheet on both faces; secured by adhesive and preferably put. in place that the attachment of the skin sheets and'the shaping of the whole is effected in a single op eration; The: skin: sheets must be ofmaterial which will yield to the required deformation. They may for example be wood veneers set with the-grain across the length of the strips; or thin plywood. The skin-sheets not only stabilisethe structure butthey strengthen it and also-help to make the whole impervious to fluids, thus en abling strips of lower quality (forinstance with small knot holes) to be used even where-anime pervious structure isrequired'. With-a suitable quality of-adhesive, the latterwill'alsocontribute to making the structure impervious.
There will be a tendency for the joints between the strips to. gape on the face which is trans-- versely convex, but ifthe-curvature is not too great, the lateral compression of" the strips will suffice to give adequate join-ts. If necessaryor desirable however the-strips. may be bevelled to avoid any possibility of gaping. Where skinsheets are used theslig-ht'gaping will-generally be of less importance.
Another way of stabilising the structure (which can also be used in conjunction with skin sheets) is tolet keys of material such as -veneer into grooves cut across the ends of" the; stripstructure and secure them with adhesive.
Where necessary the curved structure as made in the press will subsequently be-trimmed .to outline and-bevel.
A doubly curved body according to theinvention may be-synclastically curved, i. e. have its convexities facing the same way as a caskor barrel or dinghy hull, or it may be anti-clastically curved having its convexities opposed, asin the. inwardly arched'bows of a hard chine type of motor boat hull or in a saddle-shaped body.
When a number of juxtaposed strips are bent synclastically as in the case of'the staves of a cask or barrel, as abovementioned there will be a tendency for the middle portions of the strips to move apart along the line of least transverse curvature and set themselves along what may be termed. lines of longitude where they will not be subject to. transverse bending. To counteract thistendency the strips are laterally confined at least at the region of greatest tendency to spread which willigenerally be the line of least'curvature running; across the longitudinal centres of the core-strips. When the strips are bent anti-clastically with their convexities. opposed the ends of the strips will .tend to separate and lateral pressure will beappliedatleast along linespassing through the strips at or near their ends. Cor
responding arrangements will be made with more complicated forms.
The invention as applied to the manufacture of tight casks or barrels will now be described by way of example in greater detail with reference to the accompanying drawings wherein:
Figure 1 shows an unfinished stave in perspective;
Figure 2 is an exploded view of a cask;
Figure 3 shows the dismantled components of 1 the cask stacked for transport.
Figure 4 is a side view of a suitable hydraulic press; 7
Figures 5 and 6 show two forms of dies; 7 Figure 7 shows a detail; and Figure 8 shows an anti-elastically curved body.
Referring to the drawing, the cask is made up of a pluralit of identical staves 9 which are also be heated if desirable.
4 arrows AA, Figure 1 is produced by providing the base of the press with inwardly protruding bulges 2|. The opening in the base of the hydraulic press tapers from a width large enough to receive the loose core strips, down to the width the core strips are to occupy when compressed.
To keep the core strips and skin sheets hot during the moulding process and the curing of the adhesive where that is of the thermosetting type, the plunger I! may be internally heated by asteam pipe 23 connected to a steam supply by a flexible connection 24. The female die It may Any volatiles driven off during pressing will escape through the ends and sides of the work piece.
The press may be adapted to mould a number 1 of staves simultaneously. The assembly of core adapted to be held by hoops in the usual way. 5
In the example shown eight identical staves are used per cask. Casks may however also be made with four, six or ten or any other convenient whole number of identical staves, though it has been found that with four staves to the cask, i. o. with staves extending over 90", the staves do not stack very satisfactorily. As the staves are identical they can be assembled in any order and the casks when empty can be knocked down (Figure 2) and nested for transport, see Figure 3. Their re-assembly is a simple matter not calling for great skill, as distinct from the assembly of the traditional tight wooden cask with its random number of staves each of varyin width.
Each stave is made up of a plurality of core strips I I (Figure 1) which are arranged in lateral juxtaposition and are sandwiched between two veneer skin sheets l2, [3 set with the grain across the stave. The strips are all preferably of the same width and may be cut with a multiple saw from hard wood which may be of inferior quality as the strips themselves need not be liquidtight.
The amount of bending which can be effected on wood in the cold varies with the species and the proportions of the piece, though it is never very great. But the building up of the core of strip-s in accordance with the present invention uses wood in an advantageous way as regards bending. In the case of a barrel stave, if the longitudinal curvature is not too severe for the strips to be bent in the cold, then the tranverse curvature presents no substantial additional impediment, and cold bendin can be employed. If the curvature in any particular case is too severe however for cold bending, the strips and/ or the skin sheets may be given any known pretreatment to make them pliable, such as boiling in water, steaming or treatment with urea. Boiling or steaming may make for difiiculty in gluing in a hot press on account of the increased moisture content.
The strips and if desired, the backs of the skin sheets are then coated with adhesive preferably of the synthetic resin, thermosetting type, and assembled. The assembly is then placed in the base of a hydraulic press Figure 4. The base has a female die l6 resting on cross bars 8 and having a shape to which the outside face of the stave is to be conformed. The deforming pressure is applied by a male die [9 mounted on a plunger I! carried on a hydraulic ram I8. The face of the male die corresponds to the inside face of the stave to be moulded.
The lateral pressure to be applied to the middle lines of the core strips, as indicated by the strips and skin sheets are then stacked with the interposition of suitably curved and heated intermediate dies, the lowermost assembly resting on a solid base whilst the uppermost assembly is acted upon by the face of the plunger, suitable means being provided to apply the lateral con fining pressure.
The core strips and skin sheets are kept under pressure in the press until the adhesive has set. The staves are then removed and shaved or trimmed as indicated in broken lines in Figure l. The ends of the staves are crozed as at 26 for the reception of the head pieces 21.
The skin sheets are made of veneer as above described when the casks are intended for instance to hold beer or wine. The barrels or casks prior to use are washed with hot soda water to remove undesirable extractives in the inner skin sheet. The pickling liquor need only penetrate the thickness of the skin sheet as the bonding line of the adhesive eifectively seals off the bulk of the timber in each cask. Thus the pickling is more effective in the cask according to the invention than in the traditional type. The skin sheets may however be made of paper, plastic or metal if the nature of the liquid to be carried in the barrel so requires.
The skin sheets stabilize the staves as a whole so that they do not change their form with the lapse of time. The stave structure can instead be stabilized by cutting grooves (Figure 7) across the ends of the core strips assembly parallel to the faces of the stave and securing a wooden key 3| therein by adhesive.
In the application of the invention to moulding bodies of compound anti-elastic curvature, an example of which is shown in Figure 8 the base I 5 of the press has to be modified as regards the disposition of the inwardly protruding bulges for applying the lateral pressures. Two pairs of these bulges 3!) are provided to apply pressure in the direction of the arrows B, Figure 8, at or near the ends of the piece to be moulded, the shape of the male and female dies being also modified.
. It will be evident from a consideration of the foregoing description that the term strips used herein is confined-to elements, the cross section of which has a substantial thickness and a width of the same order as the thickness so that a single layer sufiices, the layer comprising a relatively high number of strips side by side.
1. A method of producing bodies of compound curvature which comprises assembling a plurality of substantially straight Wooden strips laterally coated with adhesive in lateral juxtaposition, and curving the assembly both longitudinally and 5 transversely by pressure applied normal to its plane whilst applying pressure laterally to the strips at the line or lines where the assembly has the greatest tendenc to spread under the resistance of the strips to lateral bending thereby pressing the strips into lateral contact over their Whole lengths, and maintaining these pressures until the adhesive has set.
2. A method as set forth in claim 1 also including providing the strip structure with a skin sheet on both faces, secured by adhesive.
3. A method as set forth in claim 2 in which the skin sheets are put in place before the strip assembly is pressed to shape.
4. A method as set forth in claim 1 also including pretreating the core strips before assembly to render them pliable.
5. A method as set forth in claim 1 also including grooving the strip assembly across its ends and securing keys in the grooves by adhesive to stabilize the assembly.
ARTHUR CYRIL MERRON.
References Cited in the file of this patent UNITED STATES PATENTS Number Number Name Date Wilson Sept. 13, 1927 Hutchings Oct. 9, 1934 Muller Oct. 30, 1934 Muller Nov. 20, 1934 Perry Aug. 11, 1936 Lehner Feb. 2, 1937 Hamilton Apr. 14, 1942 McDonald Apr. 25, 1944 Gramelspacher Dec. 26, 1944 Marks Mar. 13, 1945 Ramsey et a1 Apr. 25, 1950 FOREIGN PATENTS Country Date Australia Apr. 30, 1935 J Great Britain Jan. 18, 1938