JOINT BETWEEN MEMBERS AND AN ARTICLE CONSTRUCTED BY EMPLOYING THE JOINT

Abstract: Dovetail tongue and groove joints (8) between members (2, 4). To complete a conventional dovetail tongue and groove joint (5, 6, 7) it is necessary to fit the bottom part of the tongue (5b, 6b, 7b) into the top part of the groove (5a, 6a, 7a) and slide the tongue and groove relatively to each other until the tongue is secured within the groove. In the present invention the entrance (9) to the dovetail groove (8a) is dimensioned so that the widest part of the tongue (8b) can pass through the entrance (9) whereby the tongue (8b) can be pushed laterally into the groove (8a) through the entrance (9) without any relative sliding. A key member (10) is provided to fit into the groove (8a) and lock the tongue (8b) therein. An article in accordance with the present invention can be constructed by utilizing such a joint. The article comprises a number of panels (1, 2, 3, 4) joined together to form a polysided article having sides sloping outwards from the bottom.

Description: Joint Between Members and an Article Constructed by Employing the Joint The present invention relates to a joint between members, in particular to a tongue and groove joint between members, and to an article constructed by employing the joint. It is known to join members, e.g wooden panels, by using tongue and groove joints A tongue is provided on one member and a groove or slot is provided in the other member, the tongue and groove or slot being dimensioned so that the tongue will slot comfortably into the groove or slot thereby joining the members to each other. For example, consider two elongate panels each having two ends at opposite ends of the longer dimension of the panel and extending the width of the shortest dimension of the panel, and two faces. A tongue and groove joint may be formed between the two panels as followsj A tongue is provided at one end of one panel, the tongue running along the whole length of the end of the panel from the top edge to the bottom edge and extending outwards from the end of the panel. A groove is provided in the face of the other panel adjacent one end thereof, the groove running from the top edge to the bottom edge of the panel. The tongue can be joined with the groove by slotting the tongue into the groove (the groove is dimensioned such that the tongue just slots into it), thereby joining the panels to each other. A problem with a tongue and groove joint is that unles the tongue is very firmly fixed within the groove by e.g gluing or screwing, it can be pulled out of the groove thereby separating the two members which were joined. Even if glued or screwed, there is still a possibility that the joint may be forced apart if undue stress is place on it. This problem can be overcome by using a tongue and groove having a dovetail shaped cross section in place of the conventional tongue and groove i.e considering the example of the two panels described above, a tongue which broadens in width as it extends from the end of the panel, and a corresponding groove which broadens from its entrance in the face of the panel as it extends into the panel. Unlike a conventional tongue and groove joint, however, the dovetail tongue cannot be slotted into the dovetail groove merely by pushing the tongue into the groove - i.e in a conventional tongue and groove joint, as examplified above, the tongue can be pushed into the groove merely be moving the panel with the tongue in a direction corresponding with the length of the panel so that the tongue moves into the groove. In other words, the tongue can be pushed laterally (with respect to the length of the tongue running from the top edge to the bottom edge of the panel) into the groove. With a dovetail tongue and groove this cannot be done because the wide part of the dovetail tongue cannot be pushed through the entrance of the dovetail groove. Instead the bottom edge of the tongue must be engaged with the top end. of the groove (i.e the bottom edge of the panel having the tongue is placed adjacent the top edge of the panel having the groove so that the bottom edge of the tongue may fit into the top end of the groove) and the tongue and groove must then be slid relatively to each other until the tongue is slid all the way into the groove. This can give rise to a number of problems when it comes to using such joints. For example, consider the possibility of constructing a four sided article with slopi walls in the form of a frustum, from four panels by using dovetail tongue and groove joints to join the panels e.g two of the panels are provided with dovetail tongues at their ends and the other two panels are provided with corresponding dovetail grooves in one face of each panel adjacen.t opposite ends thereof. For the walls of the finished article to slope and form a frustum it is necessary that the tongues and grooves- also slope at the correct angle. It will be possible to join any three of the panels together using these joints, but extremely difficult, if not impossible, to fit the final panel in due to to the slope of the walls. For example, a first panel having a sloping dovetail tongue at either end can be joined with a second and third panel each having dovetail grooves in their respective faces adjacent each end, merely by sliding the dovetail tongue of the first panel into the groove of the second panel, then by sliding the third panel with respect to the first panel in order to mate the respective dovetail tongue with the respective dovetail groove. When this step in the construction of the article is complete three sides of the frustum are erect. To fit the forth side it is necessary to slide the tongues on the forth side into the corresponding grooves in the second and third sides. However, because of the slope of the walls of the already erect three sides it is not possible to slide both tongues in at the same time. Unless each panel is of very flexible material it is therefore not possible to fit the fourth side in place. It would not be possible to construct a frustum in this way using a rigid material such as wood, for example. If however, it were possible to fit one of the dovetail tongues into the corresponding dovetail groove by lateral movement of the tongue into the groove in a similar way to conventional tongue and groove joints i.e laterally rather than by a slidin movement, it would then be possible to easily fit the fourth side. The present invention provides a joint between members,comprising a dovetail tongue .provided on a first member and a dovetail groove or slot provided in a second member, the dovetail slot or groove being dimensioned such that its entrance is wide enough to receive the widest part of the dovetail tongue, whereby the tongue may be moved laterally through the entrance into the groove or slot, and a key member which fits into the groove or slot together with the tongue, taking up at least a portion of the space in the groove or slot which is not taken up by the tongue, whereby to lock the tongue into the groove or slot The present invention further provides a method of joining members, comprising providing a dovetail tongue on a first member and a corresponding dovetail groove or slot in a second member, the dovetail groove or slot having an entrance wide enough to receive the widest part of the dovetail tongue therethrough, engaging the tongue with the groove or slot by moving the tongue laterally through the entrance of the groove or slot, and locking the joint by inserting a key member into the groove or slot, the key member taking up at least a portion of the sapce in the groove or slot not taken up by the tongue. . The present invention has the advantage that an article such as, for example, the four sided frustum discussed above, can be constructed simply and conveniently by employing the joint in accordance with the invention in place of one of the conventional dovetail tongue and groove joints between the panels. Three of the j oints between the panels may be conventional dovetail tongue and grooves. Three of the panels would be erected as described previously. The fourth panel would then be fitted by sliding a dovetail tongue at one end of the panel into the convention dovetail groove in one face of one of the already erected three panels, as for a conventional dovetail tongue and groove joint. The fourth joint is in accordance with the invention , the remaining unjoined groove having an entrace wide enough to receive the remaining unjoined tongue at the other end of the fourth panel so that the tongue can be moved laterally into the groove. A key member is then insterted to lock the tongue of the fourth joint into the groove. Thus, with the present invention, it is possible to construct polysided articles having sloping walls, fre rigid materials such as wood whilst retaining the advantages of stability of joint given by the use of dovetail tongue and groove joints. The key member may be of any convenient shape and size to fit into the groove with the dovetail tongue to fill the space (as regards the cross-section of the groove) which is not taken up by the tongue. More than one key member could be used. For example, two key members could be used which, when combined together, take up the cross-sectional space not taken up by the tongue and therefore lock the dovetail tongue within the dovetail groove. Features and advantages of the present invention will become apparant from the following description thereof with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of a four sided frustum incorporating a joint in accordance with the present invention, the joint not yet being complete; Figure 2 shows a cross sectional view of the joint from Figure 1 ,the joint not yet being complete; Figure 3 shows a cross sectional view of the joint of Figure 2, the joint having been completed; Figure 4 illustrates a method of cutting panels from wood so that the grain runs transversly to the length of the panels; Figure 5 shows a method of cutting panels from wood so that the grain runs in the same direction as the length of the panels; Figure 6 shows a cross-sectional view of a joint in accordance with yet a further embod¬ iment of the invention; - 5a- Figure 7 shows a cross sectional view of a joint in accordance with yet a further embodiment of the present invention. Figure 8 shows a perspective view of an eight sided article which incorporates a joint in accordance with the present invention. Figure 9 shows yet a further embodiment of a joint in accordance with the present invention. th reference firstly to Figure 1 a four sided frustum is illustrated which is made up of four panels 1.2,3 and 4- Panel 1 is connected to panels 2 and 3 by conventional dovetail tongue and groove joint 5 and 6, which each comprise conventional dovetail grooves 5a,6a fashioned adjacent the ends of one face of panel 1, and corresponding dovetail tongues 5b,6b provided on the ends of panels 2 and 3 respectively. The dovetail joints 5 and 6 must be connected in the conventional manner, by placing the bottom of the dovetail tongue in the top of the corresponding groove and sliding them lengthwise relative to each other to make the join. Panel 3 is connected to panel 4 by a further conventional dovetail joint 7 . A conventional dovetail groove 7a is provided adjacent one end of the face of the panel 4 for this purpose, and a dovetail tongue 7b is provided on the end of panel 3- In order to make the final join to complete the four sided wall of the frustum it is not possible to utilise a conventional dovetail tongue and groove joint. As pointed out above in the preamble, each joint in the frustum, (i.e. the tongue and the groove) must slope in accordance with the slope of the frustum wall. It is therefore not possible to make the fourth join in the conventional manner by sliding the dovetail tongue into the dovetail groove, unless the panels are of very flexible material. If the walls of the article were vertical and the dovetail tongues and grooves therefore also vertical, it would be possible to make the fourth join at the same time as - 6 - making the third (7 n the case of the frustum) by taking the last panel (4 in the case of the frustum) having grooves adjacent ends of its face and sliding it with respect to the tongues in the 2nd and 3 ~ → panels (2 and 3 in respect of the frustum) to make the joins at the same time. this is not possible in the case of the frustum because of the angles of the walls and the joints. In the case of the present invention the joint δ is used to join panel 2 to panel 4, thus completing the frustum. the joint δ comprises a conventional dovetail tongue Sb and a conventionally shaped dovetail groove δa. However, the dovetail groove δa is of somewhat larger dimensions than the dovetail tongue δb, so that the dovetail tongue δb can be moved laterally through the entrance 9 of the groove δa as indicated by the arrow A. A key member 10 is then placed within the groove (in thedirection shown by arrow B) taking up the space not taken up by the tongue δb and locking the tongue δb within the groove δa, thus completing the joint. Figures 2 and 3 show cross-sectional views illustratin the completion of the joint δ of Figure 1. It can be seeen that the cross-section shape of the key 9 is designed to correspond with the shape of the dovetail groove δa and dovetail tongue δb, so as to lock the tongue δb securely within the groove δa. Any force applied to attempt to pull the tongue δb out of the groove δa will be transmitted by the key 9 to the walls of the groove δa, and the attempt to pull out the tongue δb will be resisted in the manner of a conventional dovetail joint. An article in the shape of a frustum can therefore be easily formed from separate panels utilising dovetail joints, as long as at least one of the joints is a joint in accordance with the present invention. - 7 - For example, the frustum illustrated in Figure 1 could be used in the manufacture of a container having sloping walls. All that it is necessary to add to the frustum to form a container is a base section. The base section would conveniently be a flat panel whose edges slope at an angle corresponding to the slope of the frustum walls. To form the container the frustum is merely turned upside down from the attitude shown in Figure 1, so that the walls slope outwards from the bottom, and the base section placed within the walls so that it sits at the bottom of the frustum with its edges abutting against the inside of the walls, the sloping walls of the frustum retaining the base in position to form a container. Such a container could easily and quickly be produced utilising a joint in accordance with the present invention. Such a container could be produced from wood i.e. four wooden panels 1,2,3 . 4 and a wooden base section. In the case of a wooden container the joint of the present invention has particular advantages. To produce such a container conventionally the three joints 5,6,7 could be conventional dovetail tongue and groove joints, as described above. Joint δ, however, could not be conventional for the reasons described above. In order to fix panel 2 to panel 4 in a conventional manner one way would be to dispense with a tongue and groov and merely abut the end of the panel 2 against the face of the panel 4 and screw by screw. In order for screws to securely hold such a join it is necessary that the grain of panel 2 run at right angles to its length, i.e. in the direction of the arrow D (Figure 1). Screwing into a panel of wood in the invention up the grain is not desirable as the screws can easily be pulled out. Cutting around in this way can lead to large amounts of waste, as illustrated by Figure 4 * - 8 - Panels 11a, lib, lie may be cut from the wood as illustrated in Figure 4 with sloping ends in accordance with the slope of the frustum wall . The direction in which the grain of the wood runs is shown by arrow E. It can be seen that if the panels are cut in this manner the wood sections 12a, 12b, 12c and 13a, 13b, 13c will be wasted. In the case of the present invention, however, all the panels 1,2,3,4 can be cut such that the direction of the grain of the wood runs along the length of the panel, because panel 2 is secured to panel 4 by a dovetail joint in accordance with the present invention. Figure 5 illustrates the case where panels llx,lly,llz are cut from wood such that the grain runs in the same direction as the length of the panels. The only waste in this case are pieces 12x,13x« The present invention therefore also has the advantage that when manufacturing a container or article having sloping walls from wood, the wood can be utilised in a much more efficient, less wasteful and cost effective manner. -9- Figure 6 shows a cross sectional vie* of a joint in accordance with the present invention which is slightly modified from the joint shown in Figures 1,2 and 3- It can be seen from Figure 3 that when the joint 8 is complete a part 15 of the key 10 can s l be seen where the panels 2 and 4 meet (i.e. on the inside corner). If it is desired that the key 10 can not be seen this can easily be done by moving the dovetail tongue, or extending the edge of the member having the dovetail tongue to hide the key. Figure 6 shows a join where the key is hidden. A member 16 is provided with a dovetail tongue 17 which fit (by lateral movement) into a dovetail groove 1 & on member 10. The tongue 17 is arranged on the member 16 such that the corner 20 of the member 16 abuts against the corner 21 of the groove lδ. When the key 22 is inserted to lock the tongue into place it cannot be seen on the inside corner, because it is hidden by the end of the member 16. Figure 7 shows a further embodiment of the joint in accordance with the present invention, which illustrates that the tongue groove and key need not necessarily con¬ form to the classical dovetail shape as illustrated in the previous section. The key 25 of Figure 7 is of a 5 curved cross-sectional shape (e.g the key is a cylind¬ er) to correspond with the curves of the dovetail tongue 26 and groove 27- Any convenient shape can be employed for the key, dovetail tongue and dovetail groo Q in accordance with the present invention as long as the tongue is wider at some point away from the member it is attached to than at a point nearer the member, so that the wide part of the tongue can act together with the key to retain the tongue within the groove. The key ~ could even be cross-shaped in cross-section, locking into -10- further grooves in the tongue and groove wall as well as locking normally. Figure 9 illustrates a joint where the key member 40 itself is provided with projecting tongues 41 and 4 arranged to fit into corresponding grooves 43^44 in panel members 45 and 4θ . The tongues and grooves 41,42,43 and 44 could be in the form of conventional dovetail tongue and grooves. This arrangement provides a very secure joint, and is particularly useful when large joints are being made. The key may conveniently be articulated to be compres ible so that it can easily be set into the join, expanding when it is in the join, to lock the joint. It can the easily be removed from the joint by compressing it and taking it out. This would have use in applications where it is desired to assemble panel members together only temporarily. For example, shutters for se in setting concrete consist of panels which are arranged together to form the desired shape for the concrete and which are removed when the concrete has set. These panels may be jointed together by joints in accordance with the present invention, and conveniently articulated keys may b used so that the panels may be separate from each other an re-joined as desired. If it is wished the joint of the present invention ca be further secured by gluing or other conventional means. The joint of the present invention will have many applications in the place of conventional dovetail tongue and groove joints, in particular because the manner in whic the present joint is constructed by moving the tongue laterally into the groove rather than by sliding it lengthwise relative to the groove, is so convenient. More than one key may be used to lock the joint. For example, it is possible to use two either side of the dovetail tongue to lock the joint. The key need not take up the entire space within the groove which is not fitted by the tongue.It is only - 1 1 - necessary that it fill part of the cross-sectional volume so as to lock the tongue within the groove. For example, in Figure 1, if the key 10 is only half the length illustrated so that it does not extend the full depth of the frustum wall and therefore leaves a gap at the bottom end of the groove it will still suffice to lock the tongue in place. Moving the tongue laterally with respect to its lengt into the groove also covers the situation where although the widest part of the tongue may actually be wider than the widest part of the groove the tongue can still fit into the groove by virtue of its shape. It is still possible to manipulate the tongue into the groove laterall with respect to its length by inserting the wide part of the tongue through the entrance to the groove at an angle, so that it fits through (it is received by) the entrance. For some applications as described above in relation to concrete shuttering it may be advantageous if the key member is removable from the joint in order that the joint may be taken apart. In order to facilitate care of removal of the key member it is possible to use an articulated key member, as mentioned above. For example the key member could be split down the middle lengthwise into two sections, the sections being forced apart from each by a spring arrangement. Forcing the sections together compresses the key for insertion into the joint i accordance with the present invention. When in the joint the two sections are forced apart by the spring arrangemen so that the key expands, locking the joint. The key member may easily be removed from the joint by compressing it and removing it. The joint of the present application advantageously has many applications. For example it could be used in the construction of an article having sloping walls in th - 12- form of a frustum described above. Dovetail joints could be used to construct all the walls of the article as long as at least one of the joints is a joint in accordance with the present invention. This problem of construction of an article with sloping walls using dovetail joint is not limited to articles having four sides but occurs with articles having any number of sides. Figure 8 shows an article having 8 sides which are connected by conventional dovetail joints 30 to 36 and a joint in accordance with the present invention 37, including key member 38. Also the disadvantages of the construction of dovetail joints are not limited to the above described problem. The method of making the joint by sliding the length of the tongue into the groove can be highly inconvenient when joining members of panels even when the dovetail tongue and groove are not arranged to slope at an angle. For example, consider the case where it is desired to join two panel members together at their edges using a dovetail groove and groove joint if the dovetail tongue and corresponding dovetail groove extend the full length of the respective edges of the panel members. In order to join the panels assembly space o'f at least twice the length of each edge is required because the end of the edge of one panel member (i.e the end of the tongue-) -.must~be ' :engaged with the end of the edge of the other panel member (i.e the end of the groove) and then must be slid for their full length until the two panel members lie interengaged side by side. The necessity for any amount of assembly space could be in some cases considerably inconvenient. It would be much more convenient if * it were possible to make the join merely by moving the dovetail tongue laterally into the dovetail groove, in the manner of normal tongue and groove joint. The use of the dovetail joint is therefore .Limited by the way in which the dovetail tongue and groove must be joined , i.e by sliding the tongue and groove lengthwise relative to each other. For example, a dovetail joint would not be likely to be choosen for the construction of a four sided frustum from -13- four panels because of the difficulty of assembly, even though a dovetail joint has many advantages with respect to other types of joints. In many other applications a conventional dovetail joint may not be used, even though it may have many advantages, because of the difficulty in assembling the joint. It would therefore be advantageous for any number of applications if it were possible to assemble a dovetail joint by moving the dovetail tongue laterally into the dovetail groove. The tongues and grooves need not be formed along the entire length of the end of a member, as has been described herein in relation to the panels of the specific embodi¬ ments. For example, in Figure 1 the tongue 8b and groove 8a may be only half the length of the ends of the panels.

Claims: - 14- CLAIMS 1. A joint between members, comprising a dovetail tongue provided on a first member and a dovetail groove or slot provided in a second member, the dovetail groove or slot being dimensioned such that its entrance is wide enough to receive the widest part of the dovetail tongue, whereby the tongue may be moved laterally through the entrance into the groove or slot, and a key member which fits into the groove or slot together with the tongue, taking up at least a portion of the space in the groove or slot which is not taken up by the tongue, whereby to lock the tongue into the groove or slot . 2. A joint in accordance with claim 1, wherein the key member is provided with a further tongue which fits into a further groove in the first or second members, whereby to further secure the joint. 3. A joint in accordance with claims 1 or 2, wherein the key member is articulated such that it can be compressed for ease of insertion to and removal from the joint. 4- A joint in accordance with claims 1, 2 or 3 wherein the first and second members are of wood. 5. A polysided article having sloping sides, comprising a plurality of separate members which are secured to each other by means of joints, at least one of the joints being a joint in accordance with any one of claims 1 to 4* 6. An article in accordance with claim 5) wherein each separate member comprises a panel, the panels being joined to form a polysided object having an open top and bottom. - 15- 7. An article in accordance with claim 5 or 6, wherein all the joints between the panels apart from the at least one joint are conventional dovetail tongue and groove joints. 8. An article in accordance with claims 6 or 7 wherein the sides slope outwards from the bottom. 9. An article in accordance with claims 6, 7 or 8 wherein there is provided a base shaped to sit in the bottom of the article, whereby to form a container. 10. An article in accordance with any one of claims 5 to 9 . wherein the members are of wood. 11. A method of joining members, comprising providing a dovetail tongue on a first member and a corresponding dovetail groove or slot in a second member, the dovetail groove or slot having an entrance wide enough to receive the widest part of the dovetail tongue therethrough, engaging the tongue with the groove or slot by moving the tongue laterally through the entrance of the groove or slot, and locking the joint by inserting a key member into the groove or slot, the key member taking up at least a portion of the space in the groove or slot not taken up by the tongue.

Inventors: GEORGE WILLIAM RODNEY, GEORGE, WILLIAM, RODNEY
Applicants: GEORGE WILLIAM RODNEY, GEORGE, WILLIAM, RODNEY
Application year: 1987
Main classification: F16B3
IPC codes: E04B1, F16B5