WO1990005246A1

WO1990005246A1 - Concrete nail

Info

Publication number: WO1990005246A1
Application number: PCT/SE1988/000584
Authority: WO
Inventors: Rune Fredriksson
Original assignee: RF-KONSULT AB
Current assignee: RF-KONSULT AB
Priority date: 1988-10-31
Filing date: 1988-10-31
Publication date: 1990-05-17
Anticipated expiration: 1991-04-30

Abstract

For attachment of metal plates to concrete, a nail (1) is used, at the point (5) of which at least two radial grooves (7, 9; 7', 9', 11') are arranged having a depth decreasing in the direction towards the head of the nail. In this way it is achieved that the nail when being driven into the concrete bends or arches inside the concrete and is anchored in such a secure way that the head (4) of said nail can be welded to the plate (15), there being no risk of having said nail being loosened from the concrete material (19) in this welding operation.

Description

Concrete nail

The present invention relates to a method of fastening metal plates to a hard base material and a nail to be used therewith, particularly for coating concrete with stainless steel plates.

In methods known in the art for coating concrete containers with stainless steel plates expansion-shell bolts are used, which are fixed in drilled holes in the container wall. Then in some way the stainless plate is fastened to the inserted expansion shell-bolt, for instance by the method that first a flat bar is attached to the container wall by mea of said expansion-shell bolts and then the edge of said plate is welded to this flat bar. However, it is a time consuming and complicated task to install the expansion-shell bolts and therefore there is a need to fin attaching means which are more easily installed.

To satisfy this need a method and a nail are provided according to the accompanying claims. Thus a nail is obtained, which on being driven into the concrete bends or arches inside the concrete. Nails intended to be driven into woo are known in the art, which are provided with points configured in a special way so that these nails bend inside the wood material, see US-A- 1 248 301. As is conventional, the nail is provided with a straight elongated shank, with a head, possibly also arranged to extend from said shank, and will apoint. The nail is made to bend inside said material on being drive into this by the fact that adjacent to said point at least two transverse grooves are arranged. These grooves have a depth decreasing in the direction away from the point of the nail and towards the head of said nail. _Ψ<

When such a nail is being driven into a hard material the nail shan is being bent or arched around said grooves or recesses. Hereby the nail is also bent totally in its forward portion inside said hard material and will give a very good anchoring. It is very remarkable to note that this also will take place when the material into which the nail is driven is very hard concrete. In these cases it has previously been a goal to drive the concrete nails used as straight as possible into the base material, for instance by providing the nail with an exactly centered point. The operation of driving said nail into a hard base material is facilitated by a hole drilled in advance in said hard base material, this hole havin dimension somewhat greater than the transverse dimension of said nail shank. The nail is generally made of steel, for attaching stainless steel often of stainless steel and is made of a steel, that is weldable. For attaching of a. stainless steel plate thus a hole is drilled through said plate and into the underlying base-material to facilitate the operation when the nail is driven into the material. In this case the nail general has a cylindrical shank and has no head extending from the shank. The length of the nail and the driving force are chosen in such a way that head of the nail or the end surface of the shank is approximately aligne with or is located somewhat outside the plate to be attached. Then the plate is welded to the end portion of the nail. The grooves in the nail shank are preferably located substantiall perpendicular to the axis of the shank and in this case two or three grooves may be suitable. The grooves may further have parallel lateral walls, i.e. they are essentially provided with a rectangular cross secti The bottom of the grooves can be flat or rounded. There is also a possibility to provide grooves having this form in an angle different f 90° to the axis of the nail in particular cases.

Further, the grooves may be configured as V-grooves, i.e. they ma have an angularly shaped section. In this case there may be preferably three grooves. The front groove, i.e. the groove located most adjacent to the poi of the nail and generally located very close to the region where the sh of the nail connects to the point, has such a depth that the bottom of said groove is located close to the axis of the nail shank. Generally s groove does not pass said axis and has a depth somewhat smaller than hal the shank diameter. The distance between the grooves is generally chose about 1 to 3 times the average width of the grooves.

On using the nail for fixing plates to a concrete base material preferably first holes are drilled in said plate, these holes having a diameter approximately equal to the diameter of the nail shank. Through these holes holes having approximately the same diameter are drilled in the concrete to a depth which is chosen depending on the characteristic the materials used and in many cases this depth may be about a third to half the length of the nail. Then the nail, which has a guiding washer applied to its rear portion, is inserted in a nail gun in such a way tha the front portion of the nail extends from the gun tool. The extending portion of the nail is then inserted into the hole drilled in advance an the the nail is driven into the material by firing said gun. If the nail ^" after being driven in extends too far away from the surface of the metal plate, the nail is cut off before the welding. This is finally made to connect the rear end of the nail to the plate and also in order to seal this connection between the nail and the plate.

When lap joints are used for connecting the coating plates to each other the nail is suitably first driven through and attached to the underlaying plate and then this plate is attached to the overlapping exterior plate by welding at the edge of this latter plate. In this case the nail is thus protected from influence from a medium to which the coating plates simultaneously protect the base material. Therefore in this case it is not necessary to make the nail of a material, that is as anticorrosive as the material of the plates used.

In joints of this kind for coating a whole wall the topmost plate is fastened first. The upper margin of this plate can be fastened by first attaching a flat bar of a suitable material to the base material, for instance by embedding the bar in the concrete wall, adjacent to the upper edge of this coating plate. Then this first topmost plate is welde at its upper edge to this embedded flat bar, wherein the upper edge of the plate is configured in such a way to form an ondulated line, for instance having a sine shape, the amplitude of which may be 40 - 50 mm and the period of which may be about 50 mm. Hereby the different retracting and expanding movements are absorbed which are generated when said plate is cooled or heated. The phenomenon concerning fatigue of the welding joint possibly occurring for plates welded with a straight upper edge can be eliminated in this way.

The upper edge of the plate could also be attached by means of the nails provided with grooves. In this case it may be suitable to place an elastic seal under said plate at its upper margin, preferably a sealing strip being placed on the rear side of the plate before driving the nail into the base material. In certain cases it may also be suitable to place another sealing strip further away from the upper edge on the rear side of said plate.

When the coating plates instead are attached to each other by mean of welded butt joints it can be suitable to first attach a flat bar at the location where the joint is to be placed. This flat metal bar is as above attached to the base material suitably by means of the nails provided with grooves. Then the plates are butt welded over said flat bar, in such a way that the weld also enters into the material of said flat bar and in this way attaches the plates thereto. Preferably the nails for attaching the flat bar has been arranged in the flat bar in such a way that their heads are not located under said weld joint.

Another possibility of attaching a plate to a concrete material is the method of first attaching, by means of a nail provided with grooves a flat bar to the wall. Then the plate is attached to said flat bar by drilling holes in the plate over said flat bar and by welding, at the edges of these holes, to the underlying flat bar.

In butt we1.ding plates over a flat bar nailed to the base material the margins of said plates may be bent in such a way that the major pa of said plate will be located at some distance from the underlying concrete walls. The space formed in this way between the plates and th base material can then be filled with concrete and in this way a bette support of said plate material is obtained which may be needed when hi pressure acts on said coating plates.

The invention will now be described with reference to the accompanying drawings in which

Fig. 1 shows a first embodiment of the nail according to the invention,

Fig. 2 shows a second embodiment of the nail according to the invention, Fig. 3 shows sectionally how coating material and base material are prepared before driving the nail into the material,

Fig. 4 sectionally shows the nail according to the invention read to be fired by means of a nail gun,

Figures 5 and 6 sectionally show the nail driven into the base material and two possibilities for welding the nail to the coating plate, Fig. 7 sectionally shows a lap joint,

Fig. 8 sectionally shows how a plate is attached to a surface coated with tiles,

Fig. 9 sectionally and also expanded shows more completely how a surface can be coated with plates having lap joints and how welding of the upper edge of the plates used can be performed,

Figures 10 and 11 sectionally shows sealing of the upper margin of the plate,

Fig. 12 sectionally and Fig. 13 seen from above show butt joints of plates over a flat bar nailed to the base material,

Fig. 14 sectionally and Fig. 15 from above show how a plate can be attached to a flat bar nailed to the base material in advance,

Fig. 16 sectionally shows assembling butt to butt plates with an improved support of the plate material, Fig. 17 sectionally shows how an inside corner can be made by means of lap joints.

In Fig. 1 is illustrated a first embodiment of the nail according to the invention, which has the reference 1 and has a shank 3 and a point 5. The nail 1 can principally be a conventional^' concrete nail haing or not having a head 4 extending from the shank. A point 5 is a conventional sloping centered point. Near this point 5 there are provided two or more grooves 7, 9, the groove 7 as is illustrated located just adjacent to the connection of the shank 3 to the sloping surface of the point 5. The groove 9 is located further away from the point and thus closer to the head 4 of the nail. These grooves can as is illustrated have substantially parallel sides and a straight or more or less rounded bottom. They can be made in the shaft 3 of the nail by means of sawing or by means of cutting with a thin abrasive wheel. Particularly the latter way of production is advantageous since in this way grooves are obtained having rounded bottom regions. Indications of fracture on these weak locations on the nail shank 3 can in this way be reduced or eliminated.

The front groove 7 extends almost up to the axis 13 of the nail, the second groove 9 having a somewhat larger distance to the this axis 13. This successive reduction of the depth of the grooves 7, 9 appears to be particularly advantageous when the nail is bent by itself when being driven into the base material, especially in a hard base material. By way of example it can be mentioned that a nail of diameter 5 mm and length 50 mm, the point 5 having a length 6 mm thereof, has been provided with two grooves 7 and 9 respectively having a width of 1,5 mm depth of 2,0 and 1,5 mm respectively and having a distance of 3 mm between the nails has appeared to work excellently when attaching plate to hard concrete, the nail 1 being made from a material conventionally used for steel nails.

A second embodiment of the invention is illustrated in Fig. 2. Here there are provided three grooves 7', 9', and 11' having depths successively decreasing from the nail point 5 to its head 4. The cross section of the grooves are in this case instead triangular, i.e. they are shaped as V-grooves. The angle of this V-profile can be between 60° and 90°. The front groove 7' is as above located just adjacent to the connection of the nail shank 3 to the point 5 and both of the grooves 9' and 11' are located at such a distance from each other and from the front groove 7' that regions of the nail shaft 3 are obtained between said grooves having the order of magnitude 1 to 3 times the average width of the grooves.

In Figures 3 - 6 is illustrated how the nail 1 is used. In a plate 15 preferably holes 17 are drilled in advance having a diameter somewha larger than the diameter of the nail. When the plate 15 then is main¬ tained for a while on the location where it is supposed to be placed, holes are drilled in the underlying concrete material 19, these holes having the same diameter as the holes in the plate and a depth corresponding to about one third to half the length of the nail. The nail 1 will then be attached in the composite hole 17 and 21. For this purpose the nail 1, which in advance has been provided with a guiding washer 23, is placed in the front portion 25 of a nail gun 27, not completely drawn. This front portion 25 is provided with a cylindrical bore 27, adapted to the diameter of said washer 23. The nail is placed in the front portion 25 n such a way that it extends somewhat from the front surface of this portion and then the point and the forward portio of the nail shank 3 are inserted into the hole 17 and 21 drilled in advance. After this he gun is fired and when the nail passes into the base material it will bend or arch inside the base material 19 in the way illustrated in figures 5 and 6. The nail shank 3, supposed to be cylindrical and not having an extending head, may after being driven into the base material extend more or less from the coating plate 15. If the nail shank 3 only extends a little from the coating plate 15 a connecting and seal ng weld can easily be arranged between the upper 5 portion of the nail 1 and the plate 15. This weld could also easily be applied if the rear end or the head 4 of the nail is more or less aligned with the surface of said coating plate 15.

When assembling coating plates 15 it may be suitable to perform in the way illustrated in Fig. 7. Here first an upper coating plate 15 10 is nailed to the base material in its lower margin by means of nails 1. The head 4 or upper part of said nail 1 is welded to the plate 15. Then a lower plate 15 is applied overlapping the upper plate 15 and completely covering the heads of the nails 1 and the weld made at these. Then both of the plates are welded together by means of a welding joint 15 31 at the upper edge of the lower plate 15. In this way the nails 1 will be completely protected from a medium, for instance a corrosive liquid, to be placed inside a vessel, the concrete wall 19 forming a portion of the walls of this vessel. This means that a simpler material can be used for the nail 1, as for instance conventional steel nails, the coating 20 plates in these case being stainless.

In Fig. 8 is illustrated anchoring a plate 15 by means of the nail 1 according to the invention in a base material that is coated with tiles. This way of attaching is quite identical to the method illustrated above for concrete walls 19 having no tile surface. 25 In Fig. 9 is illustrated an example of coating a container with stainless steel plates 15, the walls of said container consisting of concrete 19. In the upper margin of said container a flat bar 35 is embedded in the concrete, this bar 35 being of a suitable weldable steel. This bar is attached to the upper plate 15 by means of a welding joint 30 37 extending along the upper edge of said upper plate. Preferably this upper edge of the plate is configured as an undulated or wavy line, for instance having a sinusoid shape, an amplitude.of about 40 - 50 mm and a period of about 50 mm.

The lower margin of said upper plate 15 is attached as above by 5 means of suitable lap joints. By means of the top wavily shaped weld 37 an attachment is obtained between the upper plate 15 and the flat bar 35 exposing an excellent resistance to the fatigue tensions always occurring in a straight weld joint. The plates 15 are in time submitted to temperature changes and therefrom tensile or compressive forces will apppear in the upper welding joint and these are absorbed or balanced in an advantageous way when this joint has the shape of an undulated line. As is illustrated in Figures 10 and 11 the upper margin of said plate can be anchored by means of nails as above. In this case preferabl at least one sealing strip 37 is arranged under the upper margin of said plate 15. Possibly several such sealing strips 37, for instance made of butyl rubber and attached in advance to the rear side of the plate 15 may be used to sealingly connect the plate 15 to the surface of the underlying concrete material 19.

In Fig. 12 is illustrated an alternative way of making a joint between two plates. In this case first a flat bar 39 is applied on the place where the joint of the plates is intended to be located. The flat bar 39 is attached by means of nails and in performing this care is take that the heads of the nails 1 and the weld performed afterwards between these heads and the flat bar 39 will not be close to the lign where the joint of the plates will be arranged later. The plates 15 are then applied to their correct places and are welded to each other and to the underlying flat bar 39 by means of a weld 41. In this way a smooth surface is obtained in the coating 15 and simultaneously a very good attachment because of the nails 1 in the underlying material 15.

An underlying flat bar 39 can also be used on other places under the plate 15, as is illustrated in Fig. 14 and 15. In this case also, the flat bar 39 is applied in advance on a suitable location under the plate 15 by means of nails 1, which as above are welded to the plat bar 39. The plate 15 is then provided with holes 41 on the locations corresponding to the flat bar 39, and care is taken so that these holes will have no contact with the formally applied heads of the nails 1 or the welds. Then the plate 15 is welded to the flat bar 41 at the edge of these holes 41.

In Fig. 16 a coating method is illustrated, when a good support is required for the plates 15. In this case the butt weld method is used as above but either the flat bar 39 is given a larger thickness, so that it extends substantially from the wall, or the margins of the plates 15 are bent in the way illustrated in Fig. 16, for instance in an S- shape, in such a way that a suitable space is obtained between the rear side of the plates 15 and the surface of the underlying concrete material 19. In this space 43 concrete is then injected, which is allowed to harden. In this way the regions of the plate 15 being not supported and occuring in the previously described assembling methods are eliminated. Finally in Fig. 17 is illustrated how an inside corner can be made by means of the lap joint method as is described above.

Claims

Cl aims

1. A method of attaching metal plates to a hard base material, particularly concrete, characterized in that

- a nail is used adjacent to the point of which there are arranged ,. at least two transverse grooves, - the nail is driven through the metal plate into the base material, the nail being given a bend or an arch inside the base material because said grooves are compressed,

- finally the head of the nail is welded to the metal plate.

2. A method according to claim 1, characterized in that before the nail is driven into the base material holes are drilled in the metal plate and the base material, said holes having a total depth of the magnitude of order of one third to half the length of said nail.

3. A method according to claim 2, characterized in that said holes are given a diameter somewhat larger than the diameter or outer dimensio of the nail shank ^'.

4. A method according to one of claims 1 to 3, characterized in that the length of the nail is chosen in such a way that the nail after being driven into the base material extends outside the surface of the metal plate, and that the extending part of the nail is cut approximatel in alignment with the surface of said plate before said welding.

5. A nail for penetration into and attachment to a hard base material, particularly concrete, having a straight elongated shank and a point, characterized in that on the shaft and adjacent to the point of said nail there are arranged at least two transverse grooves the depth o which decreases in the direction away from the point of said nail.

6. A nail according to claim 5, characterized in that said grooves extend substantially perpendicular to the axis of said nail shank.

7. A nail according to one of claims 5 - 6, characterized\in that only two grooves are arranged.

8. A nail according to one of claims 5 - 7, characterized in that said grooves have an essentially rectangular cross section.

9. A nail according to claim 5, characterized in that only three grooves are arranged.

10. A nail according to one of claims 5 - 9, characterized in that said nails have a triangular cross section.

11. A nail according to one of claims 5 - 10, characterized in that the groove being located most closely to the point of said nail is provided with such a depth that the bottom of this groove is close to the axis of said nail shank.

12. A nail according to one of claims 5 - 11, characterized in that the groove being located most closely*; to the point of said nail is provided with such a depth that it does not extend fully to the axis of said nail shank.