The invention relates to a belt consisting of partially punched washers with holes for nail shanks for the joining of subjects, for example wood packaging such as pallets, where exterior softer materials are to be attached to harder interior materials using nails with standard heads and placing washers between the nail heads and the softer material, said nails of the type made for nailing machines.

When nailing wood packaging such as pallets and similar objects it is common procedure to join a softer material to a harder material. Since the nail shank becomes very well secured in the harder material, this part of the joint becomes the stronger part and the nail head connection with the softer material becomes the weaker part.

In such a nailed joint the nail head may be forced through the softer material under strain.

In order to counteract this drawback it is commonly known technique to use nails with heads considerably larger than normal.

However, manufacturers of nails can only with great diffi¬ culty and consequently at a higher price produce nails with large heads compared to the shank diameter.

In order to avoid the negative consequences of undersized nail heads it is a commonly known technique to place a washer under the nail head for use in connection with air-

driven nail guns.

DE Patent Specification No. 22 40 233 describes a method in connection with house construction to secure the build- ing sheets to a foundation with nails, whereby washers have been placed under the nail head in order to prevent the nail head from being pulled through the soft sheet. The nails are driven in by means of a nail gun, and the washers are available in the form of loose washers, which are carried forward to the nail gun by a double-acting pneumatic cylinder.

It is also known from DE Patent Specification No.22 35 551 in connection with house construction to place loose washers under the nail head during its chasing into the sheets to be joined, using a nail gun. In this case the nails are driven in by a pneumatic hand tool.

In addition, DE Patent Specification No. 22 38 105 describes a belt consisting of washers for use in joining exterior softer materials to harder interior materials by nails with regular sized nail heads, placing washers be¬ tween the nail heads and the softer material. This known belt is designed for use in connection with nails to be driven in by gunpowder driven bolt guns. This known belt is considerably wider than the washers punched in the belt, the washers having been provided with a centre hole for pick-up of the nail shank and with four fully punched σirle ring sections around said centre hole, each circle ring section stretching out in an arch just under 90°, whereby each washer is secured in the surrounding belt through four points consisting of neither completely nor partially punched spaces between two adjoining ends of the circle ring sections mentioned. As indicated, this belt

is considerably wider than the washers punched in the belt, and the tearing of the four points securing each washer in the belt requires considerable force.

A conventional wood pallet usually consists of three pa¬ rallel ledges, on the exterior sides of which are nailed a series of parallel boards. At each intersection between the boards and the underlying ledges a large number of nails are required. In order to produce such wood pallets, devices consisting of several nailing machines are used, placed close to one another, and it is necessary to in¬ stall thirty nailing machines on two rails, whereby all nailing machines are activated simultaneously.

The nails required are carried from a magazine through plastic tubes to each nailing machine. Due to the limited space available for each nailing machine, a belt as described in the above cited DE Patent Specification No. 22 38 105 cannot be used for the production of wood pallets of the type mentioned due to the width of the belt, which exceeds the diameter of the washers required considerably. Moreover, this known belt has a further drawback in that a considerable force is required to ex¬ tract the washer from the belt due to the four points se- curing each washer in the belt. In addition, in spite of the break lines produced by the punching of the four circle ring sections, the belt is not very flexible and consequently difficult to place under a nailing machine.

The purpose of the invention is therefore to provide a belt of the above description, which can be used in a de¬ vice for the production of pallets with a large number of nails placed close to one another by a series of nailing machines in such a way that a belt with washers is carried

to each machine, the belt being of such width as to admit the afore mentioned supply of washers and at the same time requiring a minimal force to extract a washer from the belt, and the force being so light that it may be exerted by the nailing machine itself by pulling the belt.

This will be achieved with a belt of the above descrip¬ tion, which is characteristic in that the width of the belt essentially corresponds to twice a precalculated ra- dius of a circular washer and that the belt in opposite positions of the longitudinal sides has take-outs defined by two circular arcs with a radius corresponding to the above mentioned radius, which circular arcs touch the longitudinal sides of the belt and intersect each other at points in a given distance from the longitudinal sides of the belt, which distance is only slightly less than half the width of the belt, further that between pairs of the mentioned symmetrically placed points around the center-line of the belt has been provided a break line in the belt, that the holes for the nail shanks have been made in the very middle of two neighbouring break lines, whereby the holes have been made to enclose the precal¬ culated nail shanks, and the belt has been designed to be to carried to a nailing machine intermittently and to be torn off at the break lines mentioned through a pull at the belt exerted by the nailing machine.

Designing the belt this way it will require only a mini¬ mal width, corresponding to the width of a nailing machine, whereby the belt can be used in a device with a series of nailing machines as described above, and the belt is easily carried into and torn off by the force exerted by the nailing machine, since it must be torn off at one point only, namely where a break line has been

provided. By providing only one break line the belt is made so flexible that it may be rolled up into a coil and placed in a magazine, from where it may be pulled out for later use as required.

The invention also relates to the use of the belt in a hy¬ draulic, pneumatic or mechanical nailing machine in a de¬ vice for the production of wood packaging such as wood pallets, in which several nailing machines are placed close to one another for simultaneous chasing of nails in¬ to the said wood packaging.

A highly rational manufacturing process for wood packaging is attained in this procedure.

The belt according to the invention is described in detail below with reference to the drawings, where,

fig. 1 is a cross section of a nailed joint consisting of a softer and a harder material, where the nail has a washer between the nail head and the softer material,

fig. 2 is a sectional plan of a segment of a known belt with partially punched washers,

fig. 3a is a sectional plan of a segment of a belt ac¬ cording to the invention with partially punched washers,

fig. 3b is a segment of an initial subject for a belt according to the invention prior to its punch¬ ing,

fig. 4 is a perspective drawing of a device for the nailing of pallets comprising a series of nail¬ ing machines placed close to one another,

fig. 5 is a nailing machine in perspective used in con¬ nection with the device shown in fig. 4, which nailing machine is fed a belt according to the invention.

In the nailed joint shown i fig. 1 between a softer ma¬ terial 1 and a harder material 2 a nail 3 has been driven through the softer material 1 and into the harder material 2. By major strain, for example in the form of shock im¬ pacts against the nailed joint, there is a risk that the head 4 of the nail 3 will be pulled through the softer ma¬ terial 1, due to the fact that the nail 3 is better se¬ cured in the harder material 2. The materials mentioned are usually wood of any known kind, but naturally they could be any similar materials, provided there is a diffe- rence between the extraction and the penetrating values.

In order to counteract this drawback in a nailed joint as described above it is commonly known technique to place a strong washer 5 between the nailhead 4 and the softer ma- terial 1, whereby the washer 5 is given such surface that the force necessary for driving the head 4 of the nail 3 together with the washer 5 through the softer ma¬ terial 1, essentially corresponds to the force required in order to pull the shank of the nail 3 out of the harder material 2.

In a nailed joint produced manually with a hammer the pla¬ cement of a washer 5 on the shank of the nail 3 is feasible, although it will increase the costs in material

and time.

In order to reduce the costs of nailed joints, manually operated nail guns or pneumatic, hydraulic or mechanical nailing machines are widely used.

It is difficult to use such loose washers by mechanical nailing means, and so belts of at least partially con¬ nected washers are used. The belt is lead to the nailing machine and is subsequently broken as each washer is brought or has been brought into place in a nailed joint.

The belt 6 shown in fig. 2 is designed like this. The belt has a considerable length and consists of a series of punched washers 5, the punchings consisting of a centre hole 7 with a diameter large enough to enclose the shank of a precalσulated nail 3, and of four circle ring sections 8, each stretching out in a 90° arch in such a way that the washer 5 is held in place in the belt 6 by four points or bridges 9 consisting of gaps which are neither punched completely nor partially between two adjacent ends of the circle ring sections 8.

This known belt 6 has proven quite useful in nail guns charged with gunpowder for shooting into concrete and steel.

This known belt, however, has a width that makes it un¬ suitable, owing to considerations of space, in the device 10 shown in fig. 4, which is used for producing wood packaging such as pallets where a number of parallel boards are to be nailed to another number of ledges, which are placed in the opposite parallel direction at right angles to the former. In each intersection be-

tween the boards and the ledges a large number of nails placed close to one another are required for strength, and the nails are to be driven into the wood by nailing machines 11, often numbering 30, placed on two rails 12, and the nailing machines are activated simultaneously.

In this known device 10 the nailing machines 11 are placed so close to one another that the known belt is unsuitable due to its considerable width, which also implies a con- siderable waste of unutilized belt material. In addition, the force needed to tear off the belt at the four points or bridges 9 is so significant that it can only be effec¬ ted by gunpowder-powered nail hammers.

Therefore, in the device 10 the belt shown in fig. 3 ac¬ cording to the invention is being used, and this belt 13 has been designed by removing from a long belt 13a, which has a width b primarily corresponding to twice a precal- culated radius R of a circular washer 14, in opposite po- sitions of the longitudinal sides 15 of the belt 13a, es¬ sentially triangular take-outs 16, the triangular take¬ outs 16 being defined by two circular arcs 17 with a radius corresponding to the afore mentioned radius R, and the arcs 17 touching the longitudinal sides 15 of the belt and intersecting each other at points 18 in a distance a from the longitudinal sides 15 of the belt 13a, the distance a being only slightly shorter than half of the width b of the belt 13a. In addition, between pairs of the symmetrically placed points 18 at the centre line 19 of the belt 13a a break line 20 has been provided in such a way that two neighbouring washers 14 can be separated from one another by a pull at the belt 13a exerted by the nailing machine 11. The necessary holes 21 for the shanks of the nails 3 are provided halfway between

two neighbouring break lines 20, whereby the holes 21 be¬ come concentric with the edges of the washers 14.

The belt 13 thus produced is so flexible that it may be rolled up in a magazine, pulled out later and used again in a nailing machine 11. The belt 13 has a minimal width for the purpose so that several belts 13 next to one another can each supply a nailing machine 11. Wood packaging as described may then be produced by nailing in a minimum of time and at a low and competitive price.

Fig. 4 illustrates a device 10 designed to nail wood packaging of the kind described above. The device is com¬ monly known and will not be described in detail, since the device 10 as such is not part of the invention.

The device 10 has a number of, for example 30, nailing machines 11, which may be operated by hydraulic, pneumatic or mechanical means and are placed on two rails 12 in the device. In addition, the device 10 comprises means 22 for the supply of parts for a pallet 23 to be joined, and means for the supply of nails 3 to the nailing machines 11. On top of the device 10 are magazines for belts 13 ac¬ cording to the invention, so that the belts can supply their respective nailing machines.

Fig. 5 illustrates a nailing machine 11 from the device 10 in question. The nailing machine 11 comprises means for hydraulic, pneumatic or mechanical operations, and the nailing machine receives a guided supply of a belt 13 ac¬ cording to the invention. These means are not illustrated in detail since they will be familiar to a professional. In addition, the nailing machine 11 has a channel 25 for the supply of nails 3, and 26 is the nail drift.

Each nailing machine 11 has been designed in such a way that the belt 13 is lead to the nails 3 supplied by the nailing machine 11, whereby the shanks of the nails 3 are led through the hole 21 of the washer 14, whereby the washer 14 is positioned as intended as the nail 3 is driven into the materials to be joined by the nailing machine 11.

In addition, the nailing machine 11 has been provided with a pawl mechanism made to pull out a segment of the belt 13 in a working circle with the nailing operation so that a hole 21 in the belt 13 is positioned exactly at the tip of the subsequent nail 3.

The size of the washers 14 in the belt 13 is adapted ac¬ cording to the degree of hardness, the nail hardness or the extraction value of the materials 1, 2.

Although the belt according to the invention is described in an embodiment of the invention this should not be con¬ sidered as a limitation for the invention, since the belt may be designed in several ways without deviating from the idea of the invention.

The belt according to the invention is also suitable for use in commonly known, manually operated nail guns and nailing machines, because, due to its flexibility, it may be rolled up into a coil thereby requiring a minimum of space without interfering in the use of the nail gun or the nailing machine.