GB2030878A - Structure consisting of two or more members connected together - Google Patents

Abstract

A structure, for example the frame of toy furniture is formed from square cross-section wooden members 1 and 2 each having a channel 1a, 2a running down one face and at least one hole drilled from the floor of that channel through to the opposite face of the wooden member. Connection to a similar channeled wooden member is made by way of a plastics connector 3 having a cylindrical, preferably ribbed, end and a square cross-section body dimensioned to fit snugly into the channel with the cylindrical end snugly fitting in the hole. Part of the square cross-section body projects out of the channel to engage as a friction fit in the channel of another similar channeled wooden member. Construction using this principle can be carried out without the need for any additional tools and the coupling components are all concealed from view in the finished structure. <IMAGE>

Description

SPECIFICATION Structure consisting of two or more members connected together The present invention relates to a structure formed of two or more members which are connected together, and one particular application of the invention is for a frame structure which may be used for furniture, especially toy furniture.

I propose to provide a structure comprising at least two elongate members which each have a channel therealong and are connected together by a connecting member, said connecting member having one end shaped to engage in a hole which opens into the floor of one of said channels, an adjacent portion adapted to be received in said one of the channels, and its other end adapted to be received in the channel of another of the members of the structure.

Preferably the channels each have an identical rectangular cross-section and the connecting member has said adjacent portion and said other end of square cross-section with the side of the square substantially equal to the minor side length of the rectangular cross-section of the channels.

More preferably the connecting member has at its said one end a portion of circular cross-section to engage snugly within the hole which is itself of circular cross-section. Desirably the circular cross-section projection and the hole are both cylindrical.

Advantageously the said members of the structure are of elongate form and have a square overall cross-section based on a side length of three length units, where the side length of the square crosssection of the connecting member is equal to one length unit. In such an arrangement the width of the said rectangular channel will be one length unit and the depth of the channel will be two length units so that the hole which opens into the bottom of the channel and extends through to the outside of the back face of said square cross-section of the member is one length unit in depth.

In a particularly convenient form of the invention said connecting member would be made of injection moulded plastics material and the elongate structure members themselves are made of wood.

Such a structure can be used for many purposes, in particular for a frame for toy furniture such as tables and chairs.

In order that the present invention may more readily be understood the following description is given, merely by way of example, reference being made to the accompanying drawings in which: Figure is a perspective view showing two square cross-section wooden bars joined together by a plastics connecting bar, in accordance with the present invention; Figure 2 is a perspective view looking into one end of one of the members of the structure of Figure 1; Figure 3 is a perspective view showing the connecting bar used in Figure 1; Figure 3A is a cross-section of the generally cylindrical plug portion at the end of the bar of Figure 3; Figure 4 is a perspective view showing an alterna tire form of the connecting bar;; Figure 5 is a perspective view of a further embodiment of connecting bar for forming a frame corner at which three separate mutually perpendicular frame members join; Figure 6 is a perspective view showing the frame of a table, in accordance with the present invention; and Figures 7a and 7b show alternative forms of connector component.

As shown in Figure 1, each of the wooden members or bars 1 and 2 to be joined by the injection moulded plastics connecting bar 3 is of square cross-section, in this case having a side length of 12 mm. Opening into one side of the square of the cross-section of each of the members 1 and 2 is a channel la, 2a having a width of 4 mm and a depth of 8 mm and disposed symmetrically between the two sides of the square which are parallel to the side walls of the channel.

The connecting bar 3 has a portion of square cross-section based on a side length of 4 mm, this square portion being 16 mm long, and has at its end a peg of circular cross-section, in this case a cylindrical peg, 4 mm in length and 4 mm in diameter. The connecting bar3 is shown in greater detail in Figure 3.

By engaging the connecting bar 3 with one half of its 16 mm long portion of square cross-section snugly engaged in the channel la of the bar 1 and its cylindrical end portion engaged in a holewhich extends from the floor 1b of the channel 1a and opens into the rear face 1c of the bar 1, it has been ensured that the connecting bar 3 is a tight fit and is held against rocking movement either along the channel 1a or transversely thereof. Then, simply by engaging the other half of the portion of square cross-section in the rectangular cross-section channel 2a of bar 2, it is possible to join the bars 1 and 2 together with the bar 2 arranged perpendicularly to the bar 1 and held by a friction fit of the sides of the square portion of the connecting bar in the channel 2a.

Figure 2 shows in greater detail, again in the form of a perspective view, the bar 1 with its rectangular cross-section channel la 8 mm in depth and 4 mm in width thereby leaving a surrounding wooden area of genreally U-shaped cross-section. The channel la is symmetrically disposed between the sides 1d and le, respectively, of the bar 1 with a 4 mm separation between the side walls of the channel 1a and the corresponding sides 1d and le of the square crosssection of the bar 1. Similarly, there will be a 4 mm deep wooden wall between the floor 1b of the channel 1 a and the bottom Ic of the square cross-section of the bar 1.

Extending between the floor 1b of the channel and the rear face 1c of the wooden bar 1 is a hole 4 which is in this case cylindrical based on a 4 mm diameter.

From the above, it can be seen that each of the wooden bars 1 and 2 and the plastics connecting bar 3 is based on a modular construction on units of 4 mm in length such that the dimension of 4 mm applies to the thickness of the various walls of the U-section of each wooden bar 1 and 2, the width of the channel 1a and 2a, the diameter of the hole 4, the side length of the square cross-section portion of the connecting bar 3, and the diameter of the cylindrical end peg of the bar 3. Equally, the dimension of 8 mm, i.e. two units, applies for the depth of each channel 1a and 2a. In this case the overall length of the plastics connecting bar 3 is (4 mm + 8 mm + 8 mm), i.e. five units.

Figure 3 shows the detailed form of the plastics connecting bar 3. This bar has a 16 mm long portion 5, having a square cross-section based on a side length of4 mm, and a 4 mm long cylindrical peg 6 at one end having a diameter of substantially 4 mm.

For reasons which will become apparent by reference to the description below of the assembly of a structure employing wooden bars such as 1 and 2 and the connecting bar such as 3, the cylindrical end portion of the connecting bar 3 has an overall diametes which is slightly in excess of 4 mm in order to allow a tight fit of the cylindrical end portion 6 in the hole 4 in the wooden bar.

In order to enhance the tightness of fit of the cylindrical portion 6 in the hole 4, the longitudinal crosssection of the cylindrical portion 6 is as shown in Figure 3A in that the surface of the cylindrical peg 6 is provided with ribs 7 of saw-tooth cross-section which more readily collapse by deformation in one direction (resulting from leftward movement of the connecting bar as shown in Figure 3 or upward movement of the connecting bar as shown in Figure 3A) so that as the cylindrical end portion 6 is pressed home into the hole 4 the ribs 7 collapse resilientlyto permit insertion and to engage the wall of the hole 4 with a reaction force which helps to resist subsequent withdrawal of the cylindrical peg 6.This assists in maintaining the integrity of a structure consisting of wooden bars such as 1 and 2 connected by the plastics bar 3.

The square cross-section portion 5 of the connecting bar 3 is to be a tight fit in the rectangular crosssection channel la and 2a of each bar 1 and 2, respectively, and consequently the manufacturing tolerances during moulding ofthe connecting bar3 and machining of the wooden bars 1 and 2 may be such as to favour "oversize" of the connecting bar 3 relative to the channels rather than "oversize" of the channels 1a and 2a relative to the connecting bar.

This will ensure that the fit is more likely to be tight than to be sloppy.

Bearing in mind the shape of the basic form of the connecting bar 3 and the characteristics of the cross-section of each of the generally wooden square bars 1 and 2, there will now be set out below examples of structures which can be assembled in accordance with the present invention, and examples of further forms of connecting bar which may have a more complex form than that of the basic bar 3 shown in Figure 1.

By suitable positioning of one or more holes 4 along each channel ia or 2a of the generally square cross-section bars 1 and 2, respectively, it is possible to predetermine locations at which the connecting bar 3 engages the bar 1. Thus, as envisaged in Figure 6, it may be possible to preform a table frame con sisting of four legs 8a, 8b, & and 8d and four transverse struts 9a, 9b, 9c, and 9d, a single longitudinal centre strut 10, and two top side struts 1 lea, 1 it, respectively. The table top may then be placed on the top of the frame defined by the upper side struts 11a and 11b and the upper ends of the legs 8a, 86, 8b,8c and 8d.

The table frame may be regarded as two end frames 8a, 9a, 8d, 9b, on the one hand, and ab, 9c, & 9d, on the other hand, and joined together by the centre longitudinal strut 10 and the two top side struts 11a and 11b.

Each of the various frame components 8,9 and 10 will be in the form of a bar having a shape similar to that of the bars 1 and 2 in Figure 1 and may be joined together at each of the joints by means of a connecting bar based on the type shown in Figure 3. The two top side struts 1 1a and 1 1b are, in this case, simple planks drilled with 4 mm holes near then ends to facilitate connecting to the legs 8a, 8b, & and 8d.

However, the example shown in Figure 6 of a frame structure for a table in accordance with the invention indicates that although the basic form of connecting bar shown in Figures 1 and 3 will suffice for some applications, a more complex form may be preferable in some other applications. Suitable forms of such more complex types of connecting bar are shown in Figures 4 and 5, and their use is illustrated in Figures 8a and 8b which depict the joints between wooden bars 8a and 9b in the case of Figure 8a, and bar8b,bar9cand plank ill in the case of Figure 8b. Before these joints are described in detail there follows a description of the connecting components of Figures 4, 5, 7a and 7b.

In Figure 4, the connecting bar retains the ribbed cylindrical end peg 6 and the square cross-section body portion 5 but has a 4 mm diameter cylindrical projection 11 extending perpendicularlyfrom one of the sides of the square section of the body portion 5.

This projection 11 may either be plain, or, as shown in Figure 4, ribbed.

A further embodiment, not shown, is one in which the body portion 5 has a ribbed cylindrical projection such as projection 6 butatthe opposite end of the bar as illustrated in Figure 3. This will enable two wooden bars 1 and 2 to be joined together so as to intersect but be perpendicular to one another in that one half of the length of the square cross-section body portion 5 and the adjacent cylindrical end peg 6 will engage in the channel la and hole 4 of one bar 1, and the other half of the length of the body portion 5 and the associated ribbed cylindrical peg on it will engage in the channel 2a and the hole 4 of the other bar 2 so as to secure the two members 1,2 together.

If the hole 4 in one of these members is drilled at a distance of one and a half length units (i.e. 6 mm) from an end of the wooden bar 2 then one of the side surfaces (1d or le as labelled in Figure 2) of that bar will be flush with the end face of the other bar when the bars are joined so as to be perpendicular in the configuration shown in exploded form in Figure 1.

Similarly, by providing both of the bars with a hole 4 spaced 6 mm from an end it would be possible to arrange for the two bars to be joined together in L-shaped configurations such as is required of the various bars 9 and 10 at each upper corner of the table frame of Figure 6. However, for this arrangement, the connecting bar of Figure 3 will need to be replaced by the connecting bar of Figure 4. Thus, although the exploded view shown in Figure 1 typifies one satisfactory way of assembling together the bars 1 and 2 to be perpendicular to one another, a more positive connection may be afforded by the alternative embodiment of connecting bar shown in Figure 4, as mentioned above.The hole 4 will be drilled in the bar 2 of Figure 1 6 mm (one and a half length units) from that end of the bar 2 which is visible in Figure 1 so that the transverse projection 11 of the connecting member of Figure 4 can then enter this hole to prevent withdrawal of the bar 2 away from the bar 1 in a direction along the axis of the bar 2. If the projection 11 of Figure 4 is ribbed, in the same way as is the ribbed peg 6, then an even more positive engagement will be provided.

If desired, in order to strengthen the joint an adhesive such as polyvinyl alcohol or polystyrene may be applied between the cylindrical peg 6 and the hole 4 at each joint, and possibly also between the mating flat faces comprising the side walls of each groove 1a and 2a and the cooperating faces of the square cross-section portion 5 of the connecting bar.

The connecting component shown in Figure 5 is of a construction rather more complex than the simple bar 3 shown in Figures 3 and 4, and extends the versatility of the structure.

In this case the connecting component has a body portion 12 two length units (8 mm long) having a cross-section which is one length unit (4 mm) square and at one end a coaxial ribbed projection or peg 13 identical in shape to the peg 6 of Figure 3. This peg 13 is thus one length unit (4 mm) long. A further projection, extending transversely from the end of the body portion 12 opposite that at which the peg 13 is formed, stands a two length unit (8 mm) long ribbed peg 14 which is in effect twice as long as, but otherwise identical to, pegs 13 of Figure 5 and 6 of Figure 3.

One way of using the connector component of Figure 5 would be to take three separate wooden bars, each identical to the bars typified by bars 1 and 2 in Figure 1, and then to drill, in each of the bars, a hole 4 at a distance of one and a half length units (6 mm) from an end of that bar (this distance being measured between the plane of the end of the bar and the centre of the hole 4).

The peg 14 can then be introduced downwardly into the channel of one of the bars to enter and push right home in the hole 4 of that bar. This will result in (a) the peg 13 extending coaxially from the end of that bar and (b) one half of the length of the peg 14 (the half remote from the square cross-section body portion 12) projecting beyond the back face of that wooden bar. Thus the peg 13 and the exposed half of the peg 14 form perpendicular locators on which the other two wooden bars can be attached simply by bringing the respective locator 13, 14 into the hole 4 of that other bar from the reverse side thereof (corresponding to side 1c in Figure 2).

Figures 7a and 7b show two rather more complex forms of the connecting member. Figure 7a shows a member in the form of a "T" piece of square crosssection having four4 mm long ribbed plugs 21,22 23 and 24 located one at each end of the cross bar, one projecting upwardly from the centre of the cross bar, and one projecting forwardly from the base of the stem of the "T". Thus the two plug portions 21 and 22 at the ends of the cross bar can join two channelled wooden bars coaxially simply by engaging in the 4 mm wide channels of those bars and the third plug portion 23 can be received in the hole of a third channelled wooden bar which extends perpendicularly to the plane of the paper, or indeed at any other angle permissible in view of the multi orientation fitment possibility of the plug 23 into the hole of a wooden bar.The fourth laterally extending ribbed plug portion 24 at the base of the stem of the "T" can be received in the hole of a channelled bar in which the stem 25 of the "T" lies. In this way there is the possibility of joining together four separate channelled bars, two of which are coaxial in end-to- end arrangement, and theothertwo are perpendicu lar both to one another and to the two coaxial bars.

The possibility shown in Figure 7b is of "L" shape, and again of square cross-section. It has three ribbed plug portions 26,27 and 28, again of a diameter capable of snugly fitting within a 4 mm hole. The ribbed plug portion 26 can engage in the hole in a channelled bar extending from the corner of the "L" in the rightward direction, as viewed in Figure 7b, with the channelled side facing downwardly. The ribbed plug portion 28 can engage in the hole of a channelled piece of wood in which the upright 29of the "L" lies.

The third plug portion 27 of the fitment can engage in a hole in a third channelled bar which may either be (a) parallel to the stem 29 of the "L" in which case part of the stem will be received in the groove of that third bar, or (b) perpendicular to the stem of the "L" in which case the bar will be reversed so that the projection 28 enters from the non-channelled side.

A further possibility for use of the connector component of Figure 7b is illustrated in the perspective, schematic view of Figure 7c.

The connector component shown in Figure 4 can be used in the construction of the table frame structure shown in Figure 6, as can be seen from reference to Figures 8a and 8b. These two schematic drawings show that one of the horizontal components (either 9b or 9c, as shown) of the frame can be joined to a nearby vertical component (8a or 8b as shown) using this particular form of connector. No detailed explanation of the fixing method is required since Figures 8a and 8b are self-explanatory.

The upper connector component shown in Figure 8b is not one which is illustrated elsewhere in the drawings but may be a specialised component which has an "L" portion to be received in the channel of the upright 86 so as to have its two ribbed plug portions exposed, one to engage the plank 1 lea, and the other to engage in a 4 mm diameter hole in the table top (not shown).

The construction principle of relying on bars which have rectangular cross-section channels therein has several advantages. Firstly, all the components of the structure may be made from standard starting material, i.e. channelled wooden bars and all that is necessary to make any particular structure is to cut the bars to length and to drill 4 mm diameter holes in the floor of the channel at the appropriate position.

In this way it is possible for the bars to have been given a desired surface finish (for example varnishing or other painting) before the drilling takes place and, since the various connecting members will be concealed either within the channels or within the holes, a particularly pleasing finished appearance will result.

The use of wood for the frame members such as 1, 2 and plastics material for the connecting components such as bar 3 are merely examples of suitable materials. For example the frame may, if desired, be made entirely of plastics material.

Furthermore, it is envisaged that where two members are mounted parallel, and spaced apart by cross struts, the channels in these members will be on the sides facing one another and this will permit wooden slats or other decorative members to be retained in the grooves, for example for the purpose of building a cot side or a chair back.

The structure in accordance with the present invention is particularly useful in the context of toy furniture in that it is possible for the furniture to be sold in "knock-down" form in relatively flat packs which can cheaply be stored and the furniture can then be assembled by the buyer. In the case of toy furniture, the furniture may be assembled either by the child or by an adult, and it is also contemplated that the furniture may, in the flat pack form, already consist of several finished sub-assemblies which are to be connected together by struts and connecting bars provided in the same pack.

Where, as indicated above, the channelled bars are themselves made of a plastics material, it is possible forthe channelling to be of a form which is differentfrom that illustrated in Figures 1 to 8. Thus, as shown in Figure 9, the channelling may be of T-cross-section undercut form with the spacing between the two side walls 31 and 32 of the channel less than 4 mm since the undercut construction, leaving narrow bridge portions 33 and 34 between the top wall portion and the bottom wall portion of the channelled bar, imparts a certain degree of springiness to the bar to allow the two channel wall faces 31 and 32 to be urged apart upon insertion of a 4 mm square connecting bar.

Because this particular form of connector will be made by moulding, it is possible for the holes such as 35 to be made square, and consequently the cross-section of the connecting bar may be square along its whole length even though the ends may be ribbed oversize in order to impart the desired locking effect.

Claims (14)

1. Astructure comprising at least two elongate members which each have a channel therealong and are connected together by a connecting member, said connecting member having one end shaped to engage in a hole which opens into the floor of one of said channels, an adjacent portion adapted to be received in said one of the channels, and its other end adapted to be received in the channel of another of the members of the structure.

2. A structure according to claim 1, wherein the channels each have an identical rectangular crosssection and the connecting member has said adjacent portion and said other end of square crosssection with the side of the square substantially equal to the minor side length of the rectangular cross-section of the channels.

3. A structure according to claim 2, wherein the connecting member has at its said one end a circular cross-section to engage snugly within the hole which is itself of circular cross-section.

4. Astructure according to claim 3, wherein the connecting member is a bar having a body portion of square cross-section with said annular cross-section at said one end defining a coaxial extension provided with circumferential ribs.

5. A structure according to claim 4, wherein the circular cross-section projection and the hole is also cylindrical.

6. A structure according to any one of claims 1 to 5, wherein said members of the structure have a square overall cross-section based on a side length of three length units, where the side length of the square cross-section of the connecting member is equal to one length unit.

7. A structure according to claim 6, wherein the width of the said rectangular channel is one length unit, and the depth of the channel is two length units, and the hole which opens into the bottom of the channel and extends through to the outside of the back face of said square cross-section of the member is one length unit in depth.

8. A structure according to claim 6 or7, wherein said square body portion of the connecting member is based on a cross-section of one length unit square and has a length of four length units, and wherein said projection is one length unit long.

9. A structure according to claim 8, and including a further cylindrical projection extending trans verselyfrom one side of the square of said body portion and having a diameter equal to one length unit.

10. A structure according to any one of claims 1 to 7, wherein said connecting member comprises a bar having a square body portion based on a side length of one length unit and a length of two length units; said cylindrical projection extending coaxially from said body portion at said one end of the connecting member and having a diameter of one length unit; and a further cylindrical projection extending transversely from the opposite end of said body portion with a diameter of one length unit, a length of two length units, and a spacing of the centre of said further projection from the said opposite end of the body portion equal to half a length unit.

11. A structure according to claim 10, wherein the said further projection is provided with circumferential ribs.

12. A structure according to any one of the preceding claims, wherein said connecting member is made of injection moulded plastics material and the said elongate members themselves are made of wood.

13. A structure substantially as hereinbefore described with reference to, and as illustrated in, Figures 1 to 3 of the accompanying drawings.

14. A structure according to claim 13, and including a connecting member constructed and arranged substantially as hereinbefore described with reference to, and as illustrated in, Figure 4 or Figure 5.