EP0099162B1

EP0099162B1 - A method of fastening metallic members and a punch for carrying out said method

Info

Publication number: EP0099162B1
Application number: EP19830201045
Authority: EP
Inventors: Josephus Opdam
Original assignee: Bruynzeel Intersysteem BV
Current assignee: Bruynzeel Intersysteem BV
Priority date: 1982-07-14
Filing date: 1983-07-13
Publication date: 1987-12-23
Also published as: NL8202853A; EP0099162A2; DE3374992D1; EP0099162A3

Description

This invention relates to a method of fastening metallic members wherein a metallic member is placed with the underside of a planar portion thereof in contact with a carrier material, whereafter by means of a punch at least one tongue is liberated from the metal surface, the punch entering said planar portion and the carrier material at an acute angle.
Such a method is known from US-A-2,160,258, which describes a method for fastening nailing strips of for example wood or twisted paper into channellike grooves that are formed on or into metallic members. These metallic members for example can be parts of automobiles or of furniture and the nailing strips can be used to tack upholstery on. Since the nailing strips are placed into grooves the tongues that are liberated from the metal by means of the punch only need to have such a configuration that the nailing strips can not move in a direction parallel to the walls of the groove.
The invention, however, is directed to the fastening of metallic members, such as angles and support plates, to substantially flat carrier materials such as gypsum board, wood, chip board and the like, wherein the metallic member in particular can be loaded in a direction perpendicular to the surface of the carrier material. To this end use has hitherto often been made of metallic members which on the side facing the carrier material to which they have to be fastened are provided with one or more spikes. These spikes can be hammered into the carrier material to effect a connection between the metallic member and the carrier material.
One disadvantage of this method of fastening is that, if a plurality of spikes are provided in the metallic member, these must be forced into the carrier material downwardly in substantially vertical direction. The disadvantage of this is that, when loaded, the spikes of the metallic members become easily loosened from the carrier material, so that there is not formed a reliable connection that can be loaded in various directions.
FR-A-2,297,312 describes an apparatus and a method for making a corner joint between two metal sections. For this purpose a corner piece is positioned in two sections to be connected. Subsequently, the corner joint is clamped in a suitable clamping device, and by means of a punch a tongue is punched from the metal section into the material of the corner piece on opposite sides of the corner, the tongues formed are of rectangular shape. This known connection is suitable to prevent a displacement of the metal section relative to the corner piece in the longitudinal direction of the metal section, which is sufficient for a corner joint in which the corner piece is clamped within the hollow section. When, however, the known method is used, for example, to connect a flat metal member to a flat, for example wooden panel problems occur, because owing to the shape of the tongues, they do not prevent the metal member from being displaced relatively to the panel in a direction perpendicular to the panel.
NL-A-7807256 describes a spiked metal plate for attachment to gypsum panels, in which the spikes are prevented from becoming loosened. This is only avoided, however, when the metal plate is loaded in one specific direction, while furthermore, a specially shaped metal plate is required with a weakened line, or score line, to produce the desired effect.
It is an object of the present invention to provide a method that does not have the disadvantages outlined above, and by which it is possible to fasten a randomly-shaped metallic member to a carrier material.
For this purpose the invention provides a method of the above mentioned kind wherein the punch is moved downwards in to said carrier material to bend the tongue through an angle of more than 90° to form a curved hook-shaped portion.
By means of the method according to the invention, metallic members can be secured to a carrier material extremely firmly. By adapting the force and velocity of stroke of the punch to the kind of carrier material, metallic members can be secured in a simple manner to both relatively soft material, such as gypsum board, and relatively hard material, such as cement-bonded chip board, with the metal plate being prevented from becoming detached by virtue of the hook-shaped curvature of the part bent from the metal plate. In order to make the attachment of the metallic plate still more secure, successive tongues may be bent from the metallic member into the carrier material in opposite directions, so as to fully exclude the chance of the metallic member becoming loosened in the direction of stroke of the punch, too.
The invention also provides a possible embodiment of a punch for carrying out the method, which punch has a bevel on opposite sides of the punch at the leading edge thereof. Such a punch is also known from US-A-2,160,258. The punch according to the invention differs from this known punch in that the punch is elongated with a rectangular cross-section, in that adjacent the bevels a portion of the longitudinal underside is maintained, in that the end face of the punch at the leading end has a concave curvature extending from the longitudinal underside to the longitudinal topside of the punch and in that a dam is formed at the bottom of the leading end of the punch. Such a punch appeared to be able to form a tongue with a rectangular body which tapers to the free end of the tongue, these tongues are able to sustain a large loading force in a direction perpendicular to the surface of the carrier material.
One embodiment of the invention will be described in more detail hereinafter, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 shows a top plan view of a metallic member secured to a carrier material and the punch for carrying out the method;
Fig. 2 shows a cross-sectional view, taken on the line II-II of Fig. 1;
Fig. 3 shows the punch for carrying out the method in side-elevational view;
Fig. 4 shows the punch of Fig. 4 in front- elevational view.

Figures 1 and 2 respectively show, in top plan view and in side-elevational view, a metallic member 1 secured to a carrier material 2. As shown, the metallic member is a corner-iron, but it is emphatically pointed out that the shape of the metallic member is completely irrelevant, so long as it has a planar portion to be secured to the carrier material. The metallic member 1 is secured to the carrier material by means of hook-shaped portions 3. The hook-shaped portions 3 have been formed by punching tongues from the material of the metallic member 1 by means of a punch 4, which tongues consist of tapered rectangular pieces.
By selecting a suitable shape of the punch 4, a suitable angle a relative to the carrier material, and a correct impact velocity and impact force for the specific carrier material, the tongue members can be bent into hook-shaped members in the carrier material in the manner as shown, whereby an extremely firm connection is produced. The connection is extremely strong when, as shown in the drawing, the hook-shaped portions are forced into the carrier material in opposite directions, so that loosening of the metallic members in the direction of stroke of the punch is not possible either. Depending on the size of the metallic member to be secured and the desired strength of the attachment to the carrier material, more or fewer hook-shaped portions can be struck into the carrier material.
Figures 3 and 4 show a preferred embodiment of the punch in side and front elevational view, respectively. Punch 4 is provided at its bottom, for a portion of its length, adjacent to its leading end, with a double bevel 5, 5', terminating at the bottom in a flattened portion 6 and at the front forming a dam 9. The leading end is also provided with a curvature 7, 8, extending rearwardly from dam 9. Accordingly, in front view, dam 9 has the shape of a trapezium with the short side of the trapezium being formed by the flattened portion 6. The curvature 7, 8 has been formed from two circular arcs of circles having essentially the same radius R but with centers located at different levels. The distance between the centers is indicated by x in Fig. 3. This shape of the punch has turned out to be highly favourable to produce an optimal shape and curvature of the hook-shaped portions 3.
The punch is secured in a punching device known to those skilled in the art, and in which the stroke velocity and the impact force of the punch can be adjusted, while during the performance of the punch movement the metallic member is held down on to the carrier material. By way of example, some numerical values for the dimensions of the punch and the required stroke velocity and impact force for various carrier materials and a metallic member of steel sheet having a thickness of 1 mm to be fastened will be specified hereinafter by way of example.
The punch has the following dimensions:
The punch was introduced at an angle a = 45° relative to the top surface of the metallic member, but an angle a of up to 60° has proved to be possible.

Minimum stroke velocity:

It should be noted that the above values for the dimensions of the punch and the magnitudes of stroke velocity and impact force are given by way of example only and that the desired fastening of the metallic member to the carrier material can also be accomplished using punches having different dimensions and other kinds of metals, possibly with other thicknesses, and kinds of carrier material, using different stroke velocities and impact forces, and possibly using a different angle of stroke.

Claims

1. A method of fastening metallic members, wherein a metallic member (1) is placed with the underside of a planar portion thereof in contact with a carrier material (2), whereafter by means of a punch (4) at least one tongue (3) is liberated from the metal surface, the punch (4) entering said planar portion and the carrier material (2) at an acute angle, characterized in that the punch (4) is moved downwards into said carrier material (2) to bend the tongue (3) through an angle of more than 90° to form a curved hook-shaped portion.

2. A method according to claim 1, characterized in that said tongue (3) has a rectangular body and tapers towards the free end that is to be introduced into the carrier material (2).

3. A method according to claim 1 or 2, characterized in that the metallic member (1) is fastened to the carrier material (2) with at least two hook-shaped portions (3), with the direction of stroke of the punch (4) for forming the first hook-shaped portion making an angle of about 60-90⁰with the direction of stroke for forming the second hook-shaped portion.

4. A punch for carrying out the method according to any one of claims 1-3, which punch has a bevel (5, 5') on opposite sides of the underside of the punch at the leading end thereof, characterized in that the punch (4) is elongated with a rectangular cross-section, in that adjacent the bevels (5, 5') a portion (6) of the longitudinal underside is maintained; in that the end face of the punch at the leading end has a concave curvature (7, 8) extending from the longitudinal underside to the longitudinal topside of the punch, and in that a dam (9) is formed at the bottom of the leading end of the punch.

5. A punch according to claim 4, characterized in that said concave curvature consists of two successive curves (7, 8) consisting of circular arcs of circles having essentially the same radius (R), but whose centres are spaced apart (X).