CADRES

PICTURE FRAMES

Abrégé anglais

The present invention relates to a process for manufacturing frame members
for picture frames and to the product of that process. The process comprises
the steps of forming a plastics extrusion and cutting it into lengths and
applying to the lengths of plastic extrusion a solvent based wood paste which
is then moulded or otherwise shaped such that it forms ornamentation on the
surface of the plastics extrusion and it is then allowed to dry. This process
makes use of the low cost of extrusion plastics moulding but enables the
ornamental features that would otherwise only be obtainable by injection
moulding to be obtained with the extrusion moulding.

Revendications

-6-
THE EMBODIMENTS IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for manufacturing frame members for picture frames which
process comprises steps of: forming a plastics extrusion and cutting it
into lengths; applying to the lengths of plastics extrusion a solvent
based wood paste; moulding or otherwise shaping the wood paste as
or after it is applied such that it forms ornamentation on the surface
of the length of plastics extrusion; and allowing the paste to dry.
2. A process as claimed in Claim 1, wherein the solvent of the solvent
based wood paste comprises toluene and acetone.
3. A process as claimed in Claim 1 wherein during the step of allowing
the wood paste to dry one or more extractor fans are used to draw off
the solvent vapours.
4. A process as claimed in Claim 3 wherein a said extractor fan is
operated over the extrusion as the wood paste is applied.
5. A process as claimed in Claim 1, wherein during the step of allowing
the wood paste to dry straightening forces are applied to the length of
extrusion to counteract bowing.
6. A process as claimed in Claim 3, wherein during the step of allowing
the wood paste to dry each length of extrusion is rested upon support
arms which each provide support toward a respective opposing end of
the length with the face of the extrusion to which the paste has been
applied facing upwardly and the weight of the extrusion initially
causing the ends of the extrusion to bow downwardly over the support
arms, whereby setting of the paste antagonises the gravitational
bowing such that when the paste is set the extrusion lengths will be
substantially straight.
7. A process as claimed in Claim 6, wherein there is provided a drying
rack which comprises a pair of stands which are constrained to move

-7-
together or apart along an axis and each of which has a said support
arm extending laterally therefrom such that the support arm of each
respective stand serves to support an opposing end of one or more
lengths of extrusion during the step of allowing the wood paste to dry;
and as the wood paste dries the pair of stands are moved together.
8. A frame member produced by the process of Claim 1.
9. A frame formed from a plurality of the frame members claimed in
Claim 8.

Description

1225-5 21~5561
PICTURE FR~MES
Field of the Invention
The present invention relates to ornamental frames (picture frames) and a
process for m~nllf~cturing an ornamental frame member and to a member so
formed.
Background to the Invention
The nature of a graphic work of art (or picture) such as a painting or
photographic print is such that the choice of frame within which the picture is
mounted can have a profound influence on the presentation and visual
impact of the work of art. Accordingly, a large industry has grown up to
service the demand for custom made picture frames ranging from simple
square section pine frames to elaborately carved and gilded frames of hard
wood. Inevitably, however, these frames are expensive both in terms of the
costs of the raw materials and the cost of crafting the material to form the
desired end product.
In order to meet demand for lower cost frame members primarily for high
volume sale and, most frequently, for the framing of photographs, plastics
extrusion processes have been adopted. The products of these extrusion
processes are now widely available but these do suffer the disadvantage that
heretofore they have been comparatively simple in form with no fine
embellishment or ornamentation. Whereas injection moulds allow for the
preparation of frame members or complete frames with integral

214~561
-2 -
ornamentation in the moulding, the cost of such processes are prohibitive for
large scale manufacture.
The need therefore exists for providing a process for m~king picture frame
members that has the advantage of high volume plastics extrusion
manufacture but allows ornamentation of such extrusions.
Summary of the Invention
According to a first aspect of the present invention there is provided a
process for m~mlf~cturing frame members for picture frames which
comprises the steps of forming a plastics extrusion and cutting it into lengths;applying to the lengths of plastics extrusion a solvent based wood paste;
moulding or otherwise shaping the wood paste as or after it is applied such
that it forms ornamentation on the surface of the length of plastics extrusion;
and allowing the paste to dry.
Suitably the solvent of the solvent based wood paste comprises toluene and
acetone.
Exemplary of such wood paste is a product manufactured by Cappelini Due
S.D.F. of Seregno Italy under product name wood pulp and classification
IMDG CODE 3.3 Page 3372 UN N 1263 and M.M.M. CODE 3 C21.
Wood pastes of this nature are known for adorning wood but have heretofore
not been contemplated for use in adorning plastics. Quite contrary to
expectation wood paste of this nature adheres effectively to plastics
extrusions of, for example, polystyrene to provide an attractive ornamented
finish.
It is believed that the solvent etches into the plastics material and enables the
paste to form resin bonds with the polymer of the plastics material.
Irrespective of the mechanism by which this effect is achieved, the end result
is both extremely attractive and revolutionary in the context of the picture
framing industry.
.,

- 214~56 1
-3-
As a refinement to the general technique referred to above, following
application of the wood paste to the plastics extrusion and as a result of the
fact that applying the paste tends to cause bowing of the extrusion lengths as
the wood paste sets, it is preferred to apply straightening forces to the
extrusions as the wood paste is allowed to dry.
Advantageously the extrusion lengths to which the wood paste has been
applied may be rested upon support arms which each provide support toward
a respective opposing end of each length with the face of the extrusion to
which the paste has been applied facing upwardly and the weight of the
extrusion initially c~ ing the ends of the extrusion to bow downwardly over
the support arms, whereby setting of the paste antagonises the gravitation or
bowing such that, when the paste is set, the extrusion lengths will be
substantially straight.
To this end there is suitably provided a drying rack which comprises a pair of
stands which are constrained to move together or apart along an axis and
each of which has a support arm extending laterally thereof such that the
support arm of each respective stand serves to support an opposing end of
one or more lengths of extrusion allowing the ends of the extrusion to bow
downwardly over the support arms. The support arms may be moved nearer
together by moving together the stands as the paste sets, thereby enabling
continuous correction for the bowing arising from the setting paste by
increasing the gravitation bowing effect in the opposite direction.
According to a further aspect of the present invention there is provided a
frame member produced by the process of the first aspect. According to a
yet further aspect of the invention there is provided a frame formed from a
plurality of said frame members.
Brief Description of the Drawings
A preferred embodiment of the present invention will now be more
particularly described by way of example with reference to the accompanying
drawings wherein:

2145~61
-4 -
Figure 1 is a perspective view of an embodiment of frame member; and
Figure 2 is a perspective view of a drying rack for use in the manufacturing
process.
Description of the Preferred Embodiment
Referring to Figure 1, there is shown a frame member 1 comprising a length
of polystyrene extrusion which is formed having a cross sectional profile
suitable for a picture frame member which has been cut to a suitable length
for convenient handling, storage and transportation.
As the length of extrusion is first formed by extruding through the outlet of
the mould, it has a uniform cross section along its length.
The series of ornamental tear drop shaped mouldings 2 formed on the upper
face of the extrusion are applied to the extrusion after the extrusion process
has taken place.
The ornamental mouldings 2 are prepared from a solvent-based wood pulp
or paste of a type as generally known in the wood crafting industry.
Suitable wood pastes or pulps for the purpose include those manufactured by
an Italian company Cappelini Due S.D.F. of Seregno Italy under product
classification IMDG CODE 3.3 Page 3372 UN N 1263 and M.M.M. CODE 3
C21. The example wood paste comprises the solvents acetone and toluene
which react with a polystyrene extrusion to etch into the plastics material and
bond closely therewith. From the nature of the solvents used in this
particular paste care must be taken in its use and ideally masks/goggles worn
during its handling to protect from the toxic vapours.
The paste may be applied in a mould which is placed atop the length of
plastics extrusion but preferably is applied by squirting from a dispenser
which is automated and programmed to dispense the paste in a pattern.

21~561
-s -
An extractor fan is suitably mounted above the paste application facility
within a hood extending over the facility, to draw off the solvent vapour as
soon as the paste is applied and suitably for a resting period of three to four
minutes thereafter. This has been found to drastically reduce the subsequent
drying time.
Once the paste has been applied as desired it must then be allowed to dry
over a period of days and in doing so it will tend to tension the upper surface
of the length of extrusion to which it has been applied c~llsing the length to
bow upwardly at the ends. This effect may be countered by pre-stressing the
lengths in the opposing direction.
Referring to Figure 2, a drying rack is illustrated which comprises two
substantially symmetrical stand members 3a, 3b on castor wheel 5 which are
held substantially parallel to each other and constrained to move together or
apart by means of a telescopic linkage 4a, 4b. Each stand member has an
arm 6a, 6b extending laterally from an upper end thereof to support the
lengths of extrusion which are mounted thereon extending therebetween.
Initially the two stand members 3a, 3b will be positioned apart and as the
paste dries, with evaporation of the solvent, the lengths of extrusion will
begin to bow upwardly at the ends. To counter this the stand members 3a, 3b
may then be moved nearer together, allowing the weight of the extrusions to
cause their ends to sag over the arms 6c, 6b. The separation is suitably
reduced in stages during the drying process.
To further reduce the duration of the drying period extractor fans are
suitably provided in the drying room. These assist in the drying process
although it has been found that use of extractor fans at time of application is
the single most effective measure to reduce drying time.

Dessin représentatif