GB2382054A

GB2382054A - Adjustable viewing frame

Info

Publication number: GB2382054A
Application number: GB0216282A
Authority: GB
Inventors: David Tyrrell Carlisle
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-11-19
Filing date: 2002-07-15
Publication date: 2003-05-21
Anticipated expiration: 2022-07-15
Also published as: GB0127679D0; GB2382054B; GB0216282D0

Abstract

An adjustable viewing frame for use by artists to help compose a view comprises two L-shaped frame members 10,11 each having two frame limbs at right angles to one another. The members are held in position by friction. The frame limbs have a rib 30 along one edge over which two C-shape clips, or retainers 20 engage to hold the two frame members 10,11 together where they overlap. The force exerted by the clips 20 is sufficient to hold the two frame members 10,11 together against disturbance so that the frame can be held in one hand for viewing purposes, but allows adjustments to be made easily by hand to change the size and/or relative proportions of the frame. A scale marked on a frame member allows specific relative proportions to be achieved with certainty and precision. As an alternative, the frame members may be retained by magnetic means. Or they may carry T-section slots with which linking studs (70, Figure 6a) engage. The frame may also comprise four frame limbs, each containing a T-section slot and having a T-shaped projection at one end which engages with an adjacent limb (Figures 7-9).

Description

AN IMPROVED ADJUSTABLE VIEWING FRAME This invention relates to an adjustable viewing frame. Viewing frames are well-known devices used by artists and others to help to compose a view. Known said frames include those which take the form of a piece of card with a square or rectangle cut out of it, or a piece of glass or transparent plastic with a square or rectangle marked upon it. While such frames are light and easy to make, they suffer from the disadvantage that they are not readily adjustable to form apertures of different sizes or proportions.

Adjustable frames are also known. Such frames are used, for example, for cropping pictures or photographs, and comprise two L-shape pieces of cardboard, plastic, metal or the like which are either loose or held together on a board or other structure. If the pieces are loose, the arrangement suffers from the disadvantages that they cannot easily be held in just one hand, and that they lack means for holding their two pieces in a fixed position relative to one another. If the pieces are held together on a board, they suffer the disadvantage of excessive weight, which inhibits the user from carrying them about and, especially, from holding them up in one hand while drawing or painting with the other.

The prior art also includes the frame described in US- ! 183977 which comprises four rectilinear arms with elongate central slots in them. The arms are held together in pairs by respective nuts and bolts, and the two L-shape structures thus formed are held

together but threaded pins passing through the slots onto which are screwed thumb nuts to clamp a so-called spider into the slots. This device has the advantage that it can be folded into a compact space, but the disadvantage that it is complex, involving many parts, and requires that the two thumb nuts be slackened to allow adjustment and then re-tightened when the adjustment is made.

The present invention seeks to provide an adjustable viewing frame which is an improvement over the prior art, which is quick and simple to adjust, light in weight and economical to produce.

According to one aspect of the present invention there is provided an adjustable viewing frame comprising at least two frame members having arms forming substantially rectilinear frame limbs, in which the frame members are held together by a frictional force which is sufficient to retain the frame members in a selected adjusted position but which can be overcome to effect adjustment.

In one embodiment of the invention the said frictional force is applied by retainer members. Such retainer members may be resiliently biased into engagement with the said frame members.

In one embodiment the retainer members are generally C-shape and engage respective frame members from opposite sides thereof.

Each limb of a frame member preferably has a respective shoulder extending at least

partway along the length thereof. Such shoulder is engageable by the retainer members in order to hold the frame members together.

The said shoulders of the frame limbs may comprise the side wall of an upstanding ridge or rib extending longitudinally at least part way along the frame limb. If the frame limbs are laminar elements the longitudinal ridge or ribs may be located substantially along one edge thereof. Alternatively, the said shoulder may be formed by an elongate, longitudinally extending, slot, groove or channel in each frame limb.

In such case the retainer members may have heads engaged in the said slot, groove or channel of respective frame limbs whereby to hold them together to form the said frame.

The frictional engagement of the two frame members is preferably achieved by resilient deformation of the retainer members. Such resilient deformation may be flexier, extension or compression.

The present invention also comprehends an adjustable viewing frame comprising at least two frame members having arms forming substantially rectilinear frame limbs, in which the frame members are held together by magnetic attraction sufficient to generate a frictional force which retains the frame members in a selected adjusted position, but which can be overcome to effect adjustment.

For this purpose at least part of at least one of the said frame members may be magnetised and at least part of the other frame member may be made of ferromagnetic

material. The magnetic attraction may be effected, of course, by the introduction of appropriate magnetic materials into otherwise non-magnetic members or elements such as plastics. Alternatively, plastics or other non-magnetic materials having magnetic or magnetised particles imbedded therein may be employed.

The adjustable frame of the invention may further include mounting means for mounting the frame to an easel, stand, tripod, table or other support. Such mounting means may also be used as a hand grip by which the frame may be held for viewing.

According to another aspect the present invention provides an adjustable viewing frame comprising two generally L-Shape frame members, each having two substantially orthogonal rectilinear frame limbs, and means for retaining the two members together in a selected relative position to form a relatively rectangular frame, in which at least one frame limb of each member bears a scale including indicia representing different frame limb dimensional ratios.

Various embodiments of the invention will now be described by way of example only with reference to the accompanying drawing, in which: Figure I is a perspective view of a first embodiment of the invention; Figure 2 is a partially sectioned detail view of the embodiment of Figure I taken on the line II-II of Figure 1 ; Figure 3 is a plan view of the embodiment of Figure I illustrating the use of the proportioning scale; Figure 4 is an enlarged view of a part of the embodiment of Figure 3

illustrating the proportioning scale on a larger scale; Figure 5 is a perspective view of an alternative embodiment illustrating slot and link interconnection of the frame elements; Figure 6 is a sectional view through the embodiment of Figure 5 taken on the line VI-VI of Figure 5; Figure 6a is a sectional view of a link for retaining the two frame members in the embodiment of Figure 5 and 6; Figure 7 is a schematic view of an alternative embodiment of the invention utilising four identical frame elements; Figure 8 is a schematic view of a frame element suitable for use in the embodiment of Figure 7; and Figure 9 is a perspective view of a further embodiment.

Referring first to Figure I of the drawings, this shows a frame comprising two Lshape pieces 10 and 11, typically made of plastic, metal, cardboard, composites, wood or other suitable material; which may be opaque, semi-transparent or transparent. The two L-shape pieces 10 and I I each have one arm longer than the other although in other embodiments these arms may be of equal length. In use of the illustrated embodiment the two L-shape pieces will for preference be so positioned that the long arms of the two L-shapes are opposite each other, in the position shown in Figure 1.

The two L-shape pieces 10 and I I are held together by two retainers in the form of clips 20, one positioned at the outside edge of each of the two corners where the arm of one L-shape piece crosses the arm of the other L-shaped piece: as shown in Figure

The two L-shape pieces 10 and 11 are each formed with a ridge 30 on the outside edge of each frame limb. The L-shape pieces are so made that the side which presses against the other L-shape piece is flat, with the ridge being on its other side. The clips 20 pass over the two ridges. A cross-section of this arrangement is shown in Figure 2. The ridges 30 terminate a short distance from the elbow 12 of the L-shape piece 10 or I 1, and at the free end 13,14 of each arm the ridges 30 each have a transverse stop end or shoulder 15,16. This facilitates introduction of the clips 20 at the elbow 12 upon assembly and ensures that upon enlargement of the frame the clips 20 cannot pass beyond the free ends 13,14 to allow the two L-shape pieces 10, 11 to become separated.

The clips are so formed that, when the user of the frame wishes to adjust it, the two L-shape pieces will slide easily over each other; but at the same time, the clips exert enough force to hold the two L-shape pieces in the same position relative to each other when released. The clips achieve this by being made of resilient material and being shaped so that they are stressed when engaged in position. The clips may be made of plastics; metal, composites, or other suitable materials, or of a combination of materials. A separate resilient element may be used to provide the resilient stress in other embodiments (not shown).

In the embodiment of the invention, shown in Figure 3, one L-shape piece 10 carries a scale 40, marked upon it by engraving, printing or other means, which enables the

user to set the opening between them to form a rectangle (or square) in which one side bears a specified ratio to the other, whatever the size of the opening. The scale includes ratios commonly used, in the paper industry or in art, such as for example I : 2, 1 : 1. 5, etc.

The scale is also shown in Figure 4, and comprises a plurality of longitudinal graduations lines 39 spaced at distances determined by the set proportions as represented by the ratio legends 41. Each intersection line 42, by reference to which the proportions of the frame may be set, extends at an angle from regular gradation positions marked with a scale 43 representing specific dimensions, for example centimeters.

The scale is used by placing one arm of L-shaped piece I I over a desired figure on the scale 43, and positioning the other arm of L-shaped piece I I over the appropriate intersection line 42 on the other arm of the scale, as shown in Figure 3. By selecting the appropriate intersection point between a longitudinal graduation line 39 representing the ratio and the inclined line 42 associated with the gradation number 43 corresponding to that against which the other frame limb is set, the user may construct a desired rectangle in either landscape or portrait format. As can be seen in Figure 3 the shorter frame limb is set at 6 and the longer frame limb set to the same size at a corresponding ratio of ! : 1.5 (represented on the scale by I 1/2) by selecting the intersection of the inclined line extending from 6 and the longitudinal graduation line 39 marked I 1'2.

In a further embodiment of the invention, shown in Figures 5 and 6, two L-shape pieces 60,61 are held together by different means, as follows. Each of the rectilinear limbs 62,63 of the L-shape frame member 60 has a respective elongate slot 64,65 which, as can be seen in Figure 6, has a T-shape cross section with an enlarged head portion 66 and a narrow neck portion 67.

The frame limbs 68,69 of the L-shape member 61 have corresponding identically slots as can be seen in Figure 6.

A linking stud 70 having two mushroom heads 71,72 on opposite ends of a central stem 73 fits into the intersection between two grooves or slots 64,65 at the point where two frame limbs 62,68 or 63,69 overlap. As can be seen in Figure 6a the mushroom heads 71,72 are slightly doomed so that, when fitted into the head section 66 of a slot, with the stem 73 residing in a neck portion 67, the head is slightly flexed to give a frictional inter engagement between the linking stud 70 and the slots to achieve the same frictional contact as described in relation to the C-shape clips of the earlier embodiments. The embodiment of Figures 5 and 5 has the advantage of avoiding the need for ex-turtle clips.

The embodiment of Figures 7 and 8 is different from the earlier embodiments in that it comprises four identical elongate limbs 80,81, 82,83 each, as illustrated in Figure 8, having an elongate slot 84 ofT-section extending from one end 85 to a point close to the other end 86 at which there is a T-shape projection 87 which, in assembling the frame, is engaged in a slot of an adjacent member. The four frame elements can be

pushed towards one another or pulled apart to reduce or enlarge the size of the frame opening.

Figure 9 illustrates a final embodiment of the invention in which two identical Lshape frame elements 90,91 are made from magnetised or magnetisable material, or at least material which is influenced by magnetic attraction so that they are retained in the selected position simply by magnetic attraction holding the two facing surfaces with sufficient force to generate a frictional engagement which is enough to ensure that the frame remains in the selected adjustment when in use, but not so great that it cannot be overcome by manual exertion when it is desired to vary the adjustment.

In any embodiment of the invention, one of the two L-shaped pieces may be equipped with a mounting device such as typically a handle, an arm or bracket 99, which enables the frame to be either directly or indirectly mounted on an easel, stand, tripod, table, or other support. An example is shown in broken outline in Figure 3.

Claims

CLAIMS I. An adjustable viewing frame comprising at least two frame members having arms forming substantially rectilinear frame limbs, in which the frame members are held together by a frictional force which is sufficient to retain the frame members in a selected adjusted positions but which can be overcome to effect adjustment.
2. An adjustable viewing frame as claimed in Claim I, in which the said fictional force is applied by retainer members.
3. An adjustable viewing frame as claimed in Claim 2, in which the said retainer members are resiliently biased into engagement with the said frame members.
4. An adjustable viewing frame as claimed in Claim 2 or Claim 3, in which the retainer members are generally C-shape and engage respective frame members from opposite sides thereof.
5. An adjustable viewing frame as claimed in Claim 3 or Claim 4, in which each limb of a frame member has a respective shoulder extending at least part-way along the length thereof.
6. An adjustable viewing frame as claimed in Claim 5, in which the said shoulders of the frame limbs comprise the upstanding side wall of a ridge or rib

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extending longitudinally at least part-way along the frame limbs.
7. An adjustable viewing frame as claimed in Claim 6, in which the said frame limbs are laminar elements and the longitudinal ridge or ribs is located substantially along one edge thereof.
8. An adjustable viewing frame as claimed in Claim 5, in which the said shoulder is formed by an elongate longitudinally extending, slot, groove or channel in each frame limb.
9. An adjustable viewing frame as claimed in Claim 8, in which the retainer members have heads engaged in the said slot, groove or channel of respective frame limbs whereby to link them together to form the said frame.
10. An adjustable viewing frame as claimed in any preceding claim, in which the fictional engagement of the two frame members is achieved by resilient deformation of the retainer members.
I I. An adjustable viewing frame as claimed in Claim !, in which the said frictional force is applied by magnetic means.
12. An adjustable viewing frame as claimed in Claim 11, in which at least part of at least one of the said frame members is magnetised and at least part of the other frame member is made of ferromagnetic material.

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13. An adjustable viewing frame as claimed in any preceding claim, in which at least one frame limb of each frame member is marked with a scale bearing indicia representing different frame limb dimensional ratios.
14. An adjustable frame as claimed in any preceding claim, further including mounting mans for mounting the frame to an easel, stand, tripod, table or other support.
15. An adjustable viewing frame comprising two generally L-shape frame members, each having two substantially orthogonal rectilinear frame limbs and means for retaining the two members together in a selected relative position to form a generally rectangular frame, in which two of the frame limbs of the frame formed by the said two frame members bear a scale including indicia representing different frame limb dimensional ratios.
16. A viewing frame substantially as hereinbefore described with reference to, and shown in, the accompanying drawings.