Fixing device

Abstract: Fixing device for fixing adjacent stone parts to each other, e.g. in soapstone structures. The fixing device consists of an elongated metal strip provided with gripping projections (1), which strip can be placed in grooves (5) machined in the stone parts so that the gripping projections engage the stones, locking them together. The gripping projections (1) are sharp locking edges (8) on the surface of the metal strip, which engage the sides of the grooves (5), locking the stone parts together.

Description: The present invention relates to a fixing device as defined in the preamble of claim 1. In stoves constructed of stone, a known method for fixing adjacent stones to each other is to use U-shaped hooks. For the hook, the stones to be joined together are provided with bored holes and machined grooves in the locations where the hook is to go. A U-shaped steel hook is inserted into the holes to keep the stone parts together. Between stone courses placed on top of each other, grooves machined in the upper and lower stone courses are used, a metal fillet being inserted into the groove to keep the stone courses in position. Using a hook to join adjacent stone parts together is difficult. Holes have to be bored in the stone parts and a fairly large groove has to be machined in them to accommodate the hook. In addition, with a hook it is difficult to achieve any tightening or pressure in the joint, with the result that the joint may have some play and involve problems regarding tightness. Substantially the same construction and the same problems are encountered in the fixing devices presented in Finnish patent specifications FI-B 83116 and FI-B-83559. US patent 3,214,802 presents a flat fastener having a plurality of longitudinally spaced pairs of teeth extending mainly in the longitudinal direction of the elongated fastener. The fastener is particularly useful in wooden or woodlike material when the teeth bring the edge surfaces of the wood elements into abutting engagement and place the fastener body under tension. The object of the present invention is to eliminate the drawbacks mentioned above. A specific object of the invention is to present a new type of fixing device by means of which adjacent stone parts can be joined and fixed together in a simple and effective manner. As for the features characteristic of the invention, reference is made to the claims. The fixing device of the invention consists of an elongated metal strip, made e.g. of flat iron, provided with gripping projections consisting of a series of sharp and straight locking edges on the surface of the metal strip, such that the strip can be placed in tongue-and-groove joint grooves machined in stone parts so that the gripping projections engage the stones, locking them together. According to the invention the metal strip has a single row of gripping projections arranged adjacent both ends of the metal strip, the locking edges being oriented to form a relatively small sharp angle with the direction perpendicular to the longitudinal direction of the metal strip in a plane parallel to the surface of the metal strip and in angles skewed in opposite directions at opposite ends of the metal strip so that when pushing the metal strip in the grooves the edges engage the sides of the grooves, locking the stone parts together. In an embodiment of the invention, the gripping projections are lips punched from the metal strip. The lips may be produced by punching from the middle region of the metal strip or from its edge so that the edge of the lip cuts across the edge of the strip. It is also possible that the gripping projections are formed with a suitable pressing tool as protrusions or other form of irregularities on the surface of the metal strip. Thus, the essential feature of the fixing device of the invention is that the surface of the metal strip is provided with sharp-edged shapes projecting from the smooth and even surface, by means of which the edges of the groove in the stone can be suitably gripped. Gripping projections are preferably provided on both surfaces of the metal strip. When the strip is being inserted into the groove in the stone, the strip is tightened and draws the parts being joined towards each other. Thus, the locking edges are oriented in angles skewed in opposite directions at opposite ends of the strip. The fixing device may be low enough to be completely pressed into the grooves of the stones to be joined, or it may be provided with a guiding part which, when the device is mounted in place, remains outside the grooves, serving to guide the stones above the joined stone parts into position. The fixing device of the invention has significant advantages over known technology. Using this device, adjacent stone parts can be joined firmly together by means of ordinary tongue-and-groove joint grooves easily machined in the stones. Moreover, the fixing device enables the vertical joint between two adjacent stones to be effectively tightened and pressed, which is not possible with current joining devices. In the following, the invention is described in detail by referring to the attached drawings, in which Fig. 1 presents a perspective view of a fixing device as provided by the invention, Fig. 2 presents the fixing device in Fig. 1 in side view, Fig. 3 presents the fixing device in Fig. 1 in top view, Fig. 4 presents a side view of another fixing device as provided by the invention, Fig. 5 presents a side view of a third fixing device as provided by the invention, Fig. 6 illustrates an application of the invention, Fig. 7 illustrates another application of the invention, Fig. 8 illustrates a third application of the invention, Fig. 9 illustrates a fourth application of the invention, Fig. 10 illustrates a fifth application of the invention, and Fig. 11 illustrates a sixth application of the invention, The fixing device as illustrated by Fig. 1-3 consists of a piece of flat iron, each end of which is provided with a series of gripping projections 1, which in this embodiment are lips 6, placed near one of the longitudinal edges. The lips have been formed by punching the metal strip so that the lip is cut clear of the strip on three sides, successive lips being turned in opposite directions. The lips in each end portion of the metal strip open towards its middle portion, i.e. they remain connected to the metal strip by their edges facing towards the end of the strip. Thus, the front edges of the lips, i.e. the edges turned outward and pointing toward the middle portion of the metal strip, form sharp locking edges 8. In addition, the locking edges are turned or tilted forward towards the middle portion of the metal strip from the direction perpendicular to the longitudinal direction of the metal strip so that they form a relatively small sharp angle α with the perpendicular direction. Thus, to mount the metal strip, the strip is pushed with its front edge 13 first into the groove, so that the locking edge slanting towards the middle part of the strip in the mounting direction draws and tightens the joint being made. In this embodiment, gripping projections are only provided at one edge of the metal strip while the other edge is dead flat, forming a guiding part 12 which supports and guides the stones to be placed next on the stones already joined. Fig. 4 presents another embodiment of the invention, in which the sharp-edged 8 gripping projections 1 are also lips 6 punched from the metal strip, but in this embodiment the lips start from the very edge of the metal strip. Fig. 5 presents a third embodiment of the invention, in which the gripping projections are more pronouncedly placed only in the end portions 9 and 10 of the metal strip, leaving a portion 11 free of gripping projections in the middle. Moreover, in this embodiment the gripping projections are protrusions or ridges 7 formed by suitably pressing, said protrusions forming suitable sharp edges 8. Fig. 6 presents the basic application of the invention, in which two stone parts 2 and 3 provided with a groove 5 are joined together end to end by pressing, forcing or striking a fixing device according to the invention into the grooves so that it extends in half into the groove 5 of one stone part 2 and in half into the groove 5 of the other stone part 3. Fig. 7 presents an application in which the stone parts 2 and 3 are cut to a mitre, with a metal strip with gripping projections bent into a right angle. Fig. 8 shows a corner joint without a mitre, in which a fixing device bent into a right angle is placed in a straight groove in one 2 of the stone parts and in a rectangular groove in the other stone part 3. Fig. 9 - 11 present three alternatives for implementing a corner joint with a corner stone 4 between stone parts 2 and 3 according to the invention. In other words, the fixing device of the invention allows a corner joint to be implemented in many different ways depending in each case on the most advantageous method by which suitable grooves can be machined in the stones to be joined. The fixing device of the invention can always be bent and broken into different shapes as it functions as a fixing and tightening element in the same way in different applications.

Claims: Fixing device for fixing adjacent stone parts to each other, e.g. in soapstone structures, said fixing device consisting of an elongated metal strip provided with gripping projections (1) consisting of a series of sharp and straight locking edges (8) on the surface of the metal strip, which strip can be placed in grooves (5) machined in the stone parts so that the gripping projections engage the stones, locking them together, characterized in that the metal strip has a single row of gripping projections arranged adjacent both ends of the metal strip, the locking edges being oriented to form a relatively small sharp angle (α) with the direction perpendicular to the longitudinal direction of the metal strip in a plane parallel to the surface of the metal strip and in angles skewed in opposite directions at opposite ends of the metal strip so that when pushing the metal strip in the grooves (5) the edges engage the sides of the grooves (5), locking the stone parts together. Fixing device as defined in claim 1, characterized in that the locking edges (8) consist of lips (6) formed by punching from the metal strip. Fixing device as defined in claim 1, characterized in that the locking edges (8) consist of protrusions (7) machined in the metal strip. Fixing device as defined in any one of claims 1 - 3, characterized in that locking edges (8) are provided on both surfaces of the metal strip. Fixing device as defined in any one of claims 1 - 4, characterized in that the fixing device comprises straight ends (9,10) provided with locking edges (8) and a middle portion (11) which can be bent in its lengthwise direction to allow joints to be made between stone parts at corners or otherwise in different directions. Fixing device as defined in any one of claims 1 - 5, characterized in that the metal strip comprises a guiding part (12) which remains outside the grooves (5), serving to guide the stones above the joined stone parts into position.

Inventors: HAEMAELAEINEN RISTO, HAEMAELAEINEN, RISTO, Hämäläinen, Risto
Applicants: NUNNANLAHDEN UUNI OY
Application year: 1996
Main classification: F24B1
IPC codes: F16B5, F27D1, E04B1