Jointing Jig

The present invention relates to jointing jigs and, in particular, to a novel jointing jig which may be used to assemble accurate three-dimensional corner joints as well as simple and complex two-dimensional joints.

Jointing jigs, tools and clamps are widely known and available in a variety of configurations. They are useful for construction and educational purposes. In recent years, there has developed an interest in using jointing jigs to permit students to construct three-dimensional models using preformed uniform frame members as a training exercise for solving structural problems. Modern, quick-setting adhesives have made such exercises practical and promoted interest in them. The construction of rigid structures using preformed members is, however, difficult without a tool to facilitate the assembly of accurate joints between members. Consequently, jointing jigs have been developed to facilitate the assembly of joints that permit the construction of three-dimensional structures.

An example of a jig of this type is described in British patent 2 206 834 B to Hill et al. which was published on May 1, 1991. This patent describes a simple jointing jig of one piece construction comprising a rigid body with no movable parts which is used to locate elongate parallel-sided bodies for the assembly of two-dimensional joints. While the patent teaches the use of the jig for the assembly of three-dimensional joints, the accuracy of such joints is not guaranteed and success in constructing a three-dimensional structure is not ensured.

It is an object of the invention to provide a jointing jig which permits the assembly of accurate three-dimensional corner joints.

It is a further object of the invention to provide a jointing jig which also permits the assembly of both simple and complex two-dimensional joints.

There is provided in accordance with the invention a jointing jig, comprising:

a pair of hingedly connected rigid bodies, each rigid body being formed with a plurality of channels shaped to respectively accommodate parallel-sided members to be jointed, one said channel being located along a hinged edge of each rigid body, and the channels in each rigid body having a longitudinal axis, the longitudinal axes being coplanar and intersecting, and each channel including means for locating a parallel-sided member received therein so that the parallel-sided member is inhibited from movement in at least two opposite directions normal to the longitudinal axis; and

a removable connector means for connecting the rigid bodies so that the rigid bodies are at right angles to each other and the channels along the hinged edge form a socket for receiving a one of the parallel-sided members.

The jointing jig in accordance with the invention provides a tool which is useful in the construction of accurate two- or three-dimensional joints. When locked in a folded condition, it can be used to assemble three-dimensional corner joints. When unfolded, it can be used to assemble a variety of two-dimensional joints. Although the jig is primarily intended for use in joining members of relatively small cross-section for model building and educational purposes, it is equally adapted to use in heavier constructions.

The jointing jig in accordance with the invention is preferably constructed from a molded plastics material.

The invention will now be explained by way of example only and with reference to the following drawings wherein:

FIG. 1 is a perspective view of the jointing jig in accordance with the invention;

FIG. 2 is a rear side elevational view of the jointing jig shown in FIG. 1;

FIG. 3 is a perspective view of the jointing jig shown in FIG. 1, illustrating the use of the jig to assemble a three-dimensional corner joint;

FIG. 4 is a front elevational view of the jig shown in FIG. 1 in an unfolded condition;

FIG. 5 is a front elevational view of the jig shown in FIG. 4, illustrating one use of the jig to assemble a two-dimensional joint.

FIG. 1 shows a perspective view of a jointing jig in accordance with the invention, generally indicated by reference 10. The jointing jig includes a pair of hingedly connected rigid bodies 12 and 14. The rigid bodies 12 and 14 are preferably constructed of a plastics material, which may be a sheet material or an injection-molded plastic. The rigid bodies 12, 14 are preferably hingedly connected by a flexible plastic hinge that is well known in the art and commonly referred to as a "live hinge". For jigs intended for heavy use, a mechanical hinge is preferred. Each rigid body includes a plurality of channels 18 which are adapted to accommodate parallel-sided members 20 to be jointed (see FIG. 3). Each channel 18 has a longitudinal axis and all the longitudinal axes of the channels 18 on the respective rigid bodies 12, 14 are coplanar. The members 20 are located for jointing by the channels 18. In the simplest embodiment of the invention, the side walls of the respective channels 18 locate the members 20 and inhibit movement of the members in opposite directions normal to the longitudinal axis of each respective channel 18. Other more sophisticated arrangements can be used to locate members 20 for jointing. For instance, one side wall of each channel 18 can be biased to urge members 20 against the opposite side wall which locates the member for jointing. Members 20 are commonly made from wood and are commercially available at hobby shops and the like.

The rigid bodies 12, 14 may be locked at right angles to each other using a connector 22. The connector 22 is a rigid web that includes a pair of spaced-apart upstanding ribs on each end for engaging opposite sides of a bottom edge 26 of the respective rigid bodies 12, 14. The opposite ends of the connector 22 are oriented at 90.degree. with respect of one to the other, and each pair of upstanding ribs 24 is affixed to the connector 22 in a parallel relationship with the respective opposite ends. In order to ensure accuracy of the relationship between rigid bodies 12, 14, the upstanding ribs 24 located on the opposite ends of connector 22 preferably engage a notch 28 located in the bottom edge 26 of a rear side of each rigid body 12, 14, as shown in FIG. 2.

FIG. 3 shows the construction of a three-dimensional corner joint using the jointing jig 10. Five members 20 are used in this example of a three-dimensional corner construction. Accurate corner constructions ensure that three-dimensional models may be successfully assembled. After an adhesive used to connect the members 20 has cured, the connector 22 must be removed and the rigid bodies 12, 14 rotated about the hinge 16 to release the corner construction from the jointing jig 10.

FIG. 4 shows a front elevational view of the jointing jig shown in FIGS. 1-3 with the connector 22 removed and the jointing jig in an unfolded, flat condition. This embodiment of the jointing jig 10 includes seven channels 18, indicated by the references 18a-18g. Channel 18a and 18g are parallel with the bottom edge 26 of the respective rigid bodies 14, 12, and at 90.degree. to the channels 18c, 18d located on each side of the hinge 16. Channel 18b is oriented at 45.degree. with respect to channel 18a, and channel 18f is oriented at 45.degree. with respect to channel 18g. Channel 18e is oriented at 60.degree. with respect to channel 18g and 30.degree. with respect to channel 18d, and at 120.degree. with respect to channel 18a. Other placements of the channels 18 are possible and may be preferred for some applications. The double wide channel 18c, 18 d must always be provided if the jig is to be used for corner constructions which include a vertical member (see FIG. 3).

FIG. 5 shows a use of the jointing jig 10 in the unfolded condition for constructing a two-dimensional joint in a middle region of a horizontal member 30. In this joint, a vertical member 32 and a diagonal member 34 are joined to the horizontal member 30. When the jointing jig 10 is in the unfolded condition shown in FIG. 5, the channels 18c and 18d (see FIG. 4) on each side of the hinge 16 form a channel that is twice as wide as the members 20. The position of the vertical member 32 is therefore located using a side wall of the right hand channel 18d. Accuracy of the joint may be assured by using a block 36 cut from the same stock as the members 20. Alternatively, the vertical member 32 may be clamped in position using a clamping tool or, if a quick set adhesive is used clamping may not be necessary. Diagonal member 34 is joined at a 45.degree. angle with respect to each of the horizontal member 30 and the vertical member 32.

It will be apparent to those skilled in the art that a variety of other joint configurations can be assembled using the jointing jig 10 in an unfolded condition shown in FIG. 5. The invention therefore provides a very versatile tool which permits the assembly of a variety of accurate joints.

The preferred embodiment of the invention described above is intended to be exemplary only. Changes and modifications to that embodiment may be made without departing from the scope or spirit of the invention.