PATTERNS FOR DETERMINING THE PROFILE OF AN ARCH

Abstract: A pattern for defining the profile of an arch is produced from a unitary block of material or materials having the required structural strength to support the arch materials during construction and sufficient ductility or resilience at its surface to accommodate irregularities present in the arch materials. The pattern may be produced from a single block of polystyrene material whose upper profile corresponds to the desired underside of an arch to be constructed using the pattern and whose undersurface is generally flat.

Description: This invention relates to patterns for determining the profile of a brick arch and, more especially, patterns which can be used in situ by both skilled and unskilled artisans for defining the underside profile of a brick arch spanning a passageway or the like. The invention has particular application in the construction of brick arches for gardens and as internal features of houses, restaurants and the like. When constructing a brick arch it is customary to produce a pattern comprising a sheet of wood bent to the appropriate required profile about a structure consisting of a wooden base plate and a series of angled struts extending upwardly from thee base plate. The construction of such a pattern is time consuming and requires a high degree of skill to ensure that the profile defined by its periphery corresponds to the desired profile of the underside of the arch. Additionally, the pattern, when constructed, is difficult to site because of its weight. Furthermore, its relatively hard surface means that any imperfections in bricks or mortar laid about its periphery are reflected as protrudances from the upper profile of the arch when constructed. Other conventional patterns which comprise an assembly of adjacent suitably shaped pieces lack both the necessary coherence or structural strength to achieve the pleasing appearance normally associated with brick arches. FR-A-1368700 discloses lightweight shuttering units for constructing ribbed ceilings of reinforced concrete, the shuttering units comprising polystyrene blocks of trapezoidal section about which concrete is cast. The shuttering units may either form part of the ceiling or be removed from the cast structure for re-use. This document contains no suggestion that the shuttering units disclosed can be used in the production of brick arches. According to the present invention in one aspect, there is provided a pattern for defining a profile of an arch which has sufficient structural strength to support a brick arch during construction thereof, the pattern being characterised in that it comprises a unitary block of material having a deformable upper surface whose contour complements the profile of the arch to be constructed and a generally flat undersurface, the material of the pattern having sufficient ductility or resilience at its surface to accommodate irregularities present in the arch materials. Preferably, a side face of the pattern includes markings to indicate to the user respective locations of bricks to be laid about the upper surface of the pattern. In a preferred embodiment, the pattern is produced from a unitary block of polystyrene material whose upper profile corresponds to the desired underside of the arch to be constructed using the pattern. The invention will now be described by way of example only with reference to the accompanying diagrammatic drawings in which:- Figure 1 is a front elevational view of a pattern in accordance with the invention; Figure 2 is a side elevational view of the pattern illustrated in Figure 1; and Figure 3 is a front elevational view of a pattern in accordance with the invention in use when constructing a brick arch. The pattern 1 illustrated in Figures 1 and 2 is constructed essentially from a unitary block of polystyrene and is formed on its upper surface with an arcuate profile which corresponds to the desired profile of the underside of an arch to be constructed with the assistance of the pattern. The under surface of the pattern 1 is generally flat. The width of the pattern is at least equal to the required arch width. It will, of course, be appreciated that the pattern width may, in some cases, be greater than the required arch width. The profile adopted for the pattern may take any form or shape as may the length, width and profile height above the pattern base. Thus the profile may, for example, be arcuate, elliptical, pointed or castellated. Examples of specific arches include lancet, half round, gothic, segmetal, eliptical, indian and flat arches. Further, the pattern may be supplied in any standard length and/or width, typical widths by 4″ (100 mm) and 9″ (225 mm). The patterns may be stamped direct from a suitable sheet of material and may be supplied in a variety of designs and sizes. As will be seen from Figures 1 and 2, the pattern 1 may include a rigid base 2 formed of any suitable material such as wood, metal or plastics. The base may include an inverted elongate T member 3 standing proud of its surface to provide enhanced keying and strength characteristics for the pattern; in addition, lengthwise extending side pieces 4 may be provided to enhance the rigidity of the base 2. In use, the pattern may be supported in situ at its ends by any suitable support structure. The surface of the pattern 1 may then be coated with a suitable release material before laying the required bricks and mortar about the pattern profile. The bricks are laid about the pattern with their side or end faces in contact with the upper surface of the pattern. Once the bricks have been so laid and the mortar has at least partially set, the pattern can be removed, the arch at this time being self supporting. When applying the bricks to the pattern, imperfections or protrusions present in the under surface of the bricks or mortar can be pressed into the exterior pattern surface so that the upper arch profile is of the appropriate contour. The ability to accommodate such imperfections and protrusions is, as will be appreciated, due to the inherent ductility or resilience of the polystyrene material from which the pattern is made. One or each side face of the pattern includes markings as shown to indicate to the user the spacings to be adopted for the bricks. These markings may be screen printed onto the pattern. In Figure 3, a brick arch is shown constructed about the upper profile of the pattern 1, the pattern being supported at its ends by upstanding supports 8. The bricks 9 are laid onto the pattern with their side faces in contact with the upper surface of the pattern. The invention has particular application to the construction of such arches, especially arches for gardens and as features inside houses, restaurants and outer buildings. It also has application in the construction of arched fireplaces constructed of bricks.

Claims: A pattern for defining a profile of an arch which has sufficient structural strength to support a brick arch during construction thereof, the pattern (1) being characterised in that it comprises a unitary block of material having a deformable upper surface whose contour complements the profile of the arch to be constructed and a generally flat undersurface, the material having sufficient ductility or resilience at its surface to accomodate irregularities present in the arch materials (9). A pattern as claimed in claim 1 characterised in that at least one of its side faces includes markings to indicate to the user respective locations of brichs (9) to be laid about the upper surface of the pattern. A pattern as claimed in claim 1 or claim 2 characterised in that the pattren is produced from a unitary block of polystyrene material whose upper profile corresponds to the desired underside of a brick arch to be constructed using the pattern (1). A pattern as claimed in claim 3 characterised in that the polystyrene block is mounted on a rigid base (2).

Inventors: GALLAGHER, ANTHONY
Applicants: GALLAGHER, ANTHONY
Application year: 1989
Main classification: E04G21
IPC codes: E04G21