Field of the Invention

The present invention relates to a magazine strip for screws or nails with integrated washers.

Background of the Invention

For rapid fastening by screws, it is common to use belts with screws extending through holes in the belt. An appropriate tool transports the belt though a screwing head which drives the screws one by one through the belt and into the underlying medium, for example a wall. Such belt systems are disclosed in US patent No. 6,832,696 by Donner or US patent No. 7,090,077 by Pally et al. Likewise, belts exist for nails, for example as disclosed in US patent No. 3,904,032 by Maier. Such belts are typically made of plastics, however, metal belts have been considered in European patent application EP1241363A1 by Sieber.

If screws in such belts are provided with washers, these are typically provided on the opposite side of the belt relative to the screw head, as disclosed in US patent No. 6,811,366 by Chen. Alternatively, washers may be integral parts of the belt and released from the belt together with the screw, for example as disclosed in US patent No. 3,904,032 by Maier, US patent No. 4,019631 by Lejdegaard, US patent No. 6,036,013 by Chen, US patent No. 6,620,011 by Obermeier. Likewise, disclosed in US patent No. 3.955,674 by Maier are nails in belts with integrated washers.

During production, screws are pressed into the belts either manually or by machines. Machine treatment of the screws is fastest, however, when screws are painted, for ex- ample powder painted, the machine treatment may damage part of the paint on the screw head or washer, which results in an inferior product. It would be desirable to solve this problem.

Composite washers are commercially available, where a polymer ring, typically HDPM rubber, is vulcanized onto a metal ring. Such washers may be painted sepa- rately and then placed onto the shaft of a screw. Also this handling implies a risk for damaging the paint on the screws, which is a great disadvantage.

Object of the Invention

It is the object of the invention to provide a system with composite washers minimizing the risk for damaging the paint on screws or nails and the washers during production.

Description of the Invention

This object is achieved by a magazine for driving-in elements, for example screws or nail, the magazine having integrated washers with holes arranged equally spaced in a row along a longitudinal axis of the strip magazine for stepwise supply of the elements in a magazine receptacle of a driving-in power tool. The magazine comprises a strip provided in a first material, the strip having a mid-piece, primarily flat mid-piece and edge parts longitudinally along the strip. The edge parts extend from the mid-piece so as to form an elongate cavity with the mid-piece. The cavity comprises a polymer substantially softer that the first material. The mid-piece has perforations extending through the first material of the mid-piece and through the polymer in the cavity and surrounding a portion of the mid piece and the polymer to form a composite washer. The washer is connected to a remaining part of the magazine strip by breakable ribs between the perforations.

After assembly, a driving element with a head and a shaft extends with its shaft through a hole in the washer. In most embodiments, it is preferred to have the head of the screw or nail on the opposite side of the first material relatively to the softer polymer.

Such a strip is suitable for being painted after assembly of the driving-in elements into the magazine. The advantage is the fact that the elements are subjected to the roughest handling, namely the insertion, prior to the painting. This handling implies less dam- age to the paint on the surface of the elements. In addition, the insertion into the strip magazine has the advantage that the transport system of the elements into and through the painting machine can be provided by simple means, because the driving-in elements are already ordered in the magazine itself, which is easy to handle by the ma- chine. Whereas prior art machines have to pick up screws or nails one by one for the painting, this is facilitated by the invention, because not the driving-in elements have to be picked up, but the strip only has to be guided through the painting machine.

For example, the following method may be used for the production of painted screws or nails:

- providing driving-in elements with heads for driving the elements into a medium,

- providing a magazine with washers as described above, for example a flat, elongated strip magazine having integrated washers with holes arranged equally spaced in a row along a longitudinal axis of the strip magazine for stepwise supply of the elements in a magazine receptacle of a driving-in power tool,

- inserting the elements into and through the holes of the washers, and subsequently

- painting the heads of the elements while located in the holes.

In some cases, it is desired to use powder painting at a temperature above 180 ⁰ C. In this case, the strip magazine is made of an electrically conducting material resistant to this temperature. Preferably, the first material is a metal, for example aluminium or steel, although other materials are possible, for example carbon materials or conducting, thermo-resistant polymers.

It is advantageous to provide a distance of more than 1 mm, for example equal to or more than 2, 3, 4, or 5 mm, between the washer and the head of the screw or nail for allowing paint to enter the space between the head and the washer.

In a concrete embodiment, the method comprises - providing a strip, for example a metal strip, with a mid-piece, primarily a flat mid- piece, for example with a substantially endless flat mid-piece,

- stamp punching or calendar punching holes for driving-in elements into the mid- piece - subsequently inserting the driving-in elements into the holes,

- and then painting the heads of the driving-in elements while located in the strip.

In order to increase the stability of the strip magazine, there may be provided edge parts, for example flat edge parts, along the strip extending from the mid-piece, for example extending laterally. The edge parts may extend at right angles form the mid- piece, but this is not necessary, as the edge parts may extend under a sharp angle between the edge parts and the mid-piece. For example, the edge parts may have an angle of between 70 and 110 degrees with the mid-piece in order to stabilize the strip

One possible solution is an aluminium strip, preferably extruded. Laterally extending edges may be provided as part of the extrusion process. For example, the edge parts may have an L-form, which means that they extend perpendicular in one direction from the mid-piece. An example of this cross sectional shape is disclosed in International patent application WO 93/09918. Another example is edge parts having a T- form, which means that they extend perpendicular in two directions from the mid- piece. An example of this cross sectional shape is given in German Utility Model DE 200 02 058.

If the edge parts are not provided by extrusion, there are other possibilities, among which calendar rolling of the strip is one option.

If the strip magazine is provided with laterally extending edge parts, these edge parts may be provided with V-shaped slots much in the way as illustrated in International patent application WO 93/09918 in order to allow bending of the strip magazine despite the lateral edge parts. The slots, if equidistant longitudinally along the magazine, are also useful for precise advancing of the magazine through the power tool. In addition, there may be provided weakening lines from one slot on one edge part to a slot on the opposite edge part such that these weakening lines traverse the mid-piece perpendicular to a longitudinal axis of the strip magazine. For example, such weakening lines can be provided by thinning the material along the lines by calendar rolling. For example, the production method comprises attaching a polymer material to one side of the strip before punching holes into the mid-piece. In addition, perforations are punched into the mid piece and through the polymer layer, the perforations surrounding a portion of the magazine strip to form a washer, where the washer is connected to a remaining part of the magazine strip by breakable ribs between the perforations.

A preferred polymer is rubber, especially ethylene propylene diene M-class (EPDM) rubber, which is also resistant to temperatures above 160 ⁰ C, preferably between 160 ⁰ C and 200 ⁰ C or between 180 ⁰ C and 200 ⁰ C or between 200 ⁰ C and 220 ⁰ C, which is the normally used temperature range for powder painting.

By providing a magazine strip with an upper material which is a hard material, for example metal or carbon fibre material, and a lower material, which is a soft material, like rubber, the punching process for the holes and the perforations around the washer is easier than if the strip material were entirely soft, because substantial deformation or even collapsing of the strip during the process is prevented. Thus, the advantages of a soft damping or tightening material of the washer, such as rubber or polymer foam, can be combined with the advantage of a hard and durable washer surface against which the screw is driven.

Description of the Drawing

The invention will be explained in greater detail with reference to the drawing, where

FIG. 1 illustrates a system for production of a strip magazine,

FIG. 2 illustrates an embodiment of a strip magazine for screws with washers inte- grated in the magazine,

FIG. 3 illustrates a strip magazine with edge parts having local deformations supporting a polymer band,

FIG. 4 illustrates a further strip magazine with edge parts having local deformations supporting a polymer band, FIG. 5 illustrates a magazine with straight edge parts bent towards the cavity supporting a polymer band, FIG. 6 illustrates a magazine with L-formed edge parts supporting a polymer band, FIG. 7 illustrates a magazine with rounded edge parts bent towards the cavity supporting a polymer band,

Detailed Description of the Invention

FIG. 1 illustrates a system 1 for production of the magazine strip 2 according to the invention. The system 1 comprises a substantially endless strip 2 which is running 14 through the different machines 15, 13, 12, 4. The strip 2 is provided with holes 11 into which screws 8, or alternatively nails or bolts, are inserted. The screw 8 has a head 7 and a threaded shaft 9.

The substantially endless strip 2' is joined with a polymer, for example by providing a polymer band 24 that is glued, vulcanized or melted onto the lower surface of the strip 2', or the polymer is provided as a melt onto the surface. The combined strip 2'" is punched in a machine 12 and/or 13 to provide holes 11 and perforations 22 to form a washer 5.

Screws 8 are inserted into the holes 11 of the washer 5 for painting in the painting station 4. In order that the washer 5 also receives paint, there is provided a distance 3 between the washer 5 and the screw head 7 for example with a distance 3 of more than or equal to 1, 2, 3, 4, or 5 mm between the lower edge of the screw head 7 and the upper edge of the washer 5 as indicated in FIG. 1.

Alternatively, a polymer band 24 may be joined with the strip 2', before the strip 2' is exposed to an edge deformation in a metal rolling machine 15. For example, the rolling machine 15 causes a deformation of a flat sheet into a substantially U-formed or C- formed magazine 2 having laterally extending side edge parts 18.

After having traversed the painting station 4, the substantially endless strip may be cut into shorter pieces, for example pieces of 30 or 50 cm. The term "endless" strip does not actually mean that the strip is endless but is a jargon in the field for strips that are very long, for example more than 10 meters. The holes in the strip 2 are provided by corresponding machines. For example a stamp punch machine 12 may be used or a calendar punch machine 13 or a combination of both. A strip 2', 2" without holes may be provided from a strip source 16, for example an extruder or a magazine of rolled up metal bands. If the initial strip is provided from a magazine of flat rolled up metal bands, the flat band 2' ' may be formed into a strip 2' with laterally extending side edges by using appropriate machines, for example metal rolling machines 15.

An example of a part of a magazine strip 2 is illustrated in FIG. 2. For sake of illustra- tion, the magazine strip 2 on FIG. 2 is shorter than it will usually be. The magazine strip 2 has a mid-piece 21 and edge parts 18 extending laterally from the mid-piece. The edges 18 stiffen the strip 2.

In order for the strip 2 in FIG. 2 to follow bending trajectories through the screwing head or nailing head of a driving-in power tool, the magazine strip may be provided with slots 28, for example V-shaped slots as illustrated in FIG. 2, though other slot forms are possible. The lateral edges may then be used for guiding a strip in a driving- in power tool, for example as illustrated in German Utility Model DE 200 02 058 or in International Patent Application WO 93/09918. The slots 28 can be used, in addition, for a safe and precise advancing of the strip 2 in a machine. The lateral edges 18 are also useful in a punching machine 12, 13, because the lateral edges 18 may be held in a corresponding guide rail in the punching machine 12, 13 and prevent deformation or even collapsing of the strip 2 during punching. For this sake, a metal rolling machine 15 for forming the lateral edges 18 is preferred rather upstream than downstream of the punching machine 12, 13, as also illustrated in FIG. 1

As illustrated in FIG. 2, washers 5 are provided as integral portions of the magazine strip 2. The washers 5 are provided through perforations/cut-outs 22 in the form of circular arcs, for example obtained by punching as described above. The washers 5 are connected by ribs 23 to the remaining part 25 of the magazine strip 2. The ribs 23 act as break points when the screw 8 is driven through the magazine strip 2 such that the washer 5 is detached from the remaining part 25 of the strip 2 and follows the screw 8. As illustrated in FIG. 2, the magazine strip 2 is provided with a polymer layer 24 on the opposite side of the magazine strip 2 relatively to the side facing the screw head 7. The perforations 22 extend also through the polymer layer 24 such that the entire washer 5 is released from the remaining part 25 of the magazine strip 2, the entire composite washer 5 comprising a first layer of a stiff material, for example metal, and polymer layer 24.

In FIG. 3, the magazine strip 2 is also provided with a plurality of local deformations 26 of the edge parts 18, the local deformations 26 being in the form of indentations. The plurality of local deformations 26 towards the concavity 27 of the U-formed magazine strip 2 prevents the polymer band 24 from leaving the magazine strip 2 even in the case that the polymer band 24 is not glued or vulcanized onto the strip 2. Thus, the polymer band 24 is held by the strip 2 due to the local deformations 26.

Once, the screws are inserted into the strip 2, the friction between the polymer part of the washers 5 and the screw shaft 8 secures the polymer band additionally to the screws. For example, the friction between the washers 5 and the screw shaft 8 may be provided with protrusions that extend radially inward from the washers towards the screw shaft as disclosed in US patent No. 6,036,013 by Chen.

In the case that local deformations 26 are used to hold the polymer band 24 against the strip 2, the band may be bent into the U-form as well, for example through the metal rolling process, or may be provided in U-form, as illustrated in FIG. 3. Alternatively, the polymer band may be provided in a flat form, as illustrated in FIG. 4. In this case, the polymer band need not vulcanised onto the strip 2 but held in place due to the local deformations 26 of the lateral edges 18.

Optionally, the polymer band 24 may - in addition to the local deformations 26 - be glued onto the strip in order to prevent deformation of the polymer band when screws are inserted into the holes 11. Using glue instead of vulcanisation simplifies the production process substantially. Also, the glue need not cover the entire contact area between the strip and the polymer band. For example, it suffices to support the polymer band, on the one hand, by the local deformations 26 at the edges 18 and, on the other hand, by one or more lines of glue along the strip 2 near the washers 5 and/or at the position of the washers 5.

As an alternative to the local deformations, the polymer band 24 may also be held in place, if the edges 18' are bent an angle V of more than 90 degrees, for example, as illustrated in FIG. 5. Thus, the edge parts 18' form a sharp angle W with the mid-piece

21, and the edge parts 18' have edges 31 that are distanced d apart, which is smaller than the width D of the mid-piece 21. Also, in this embodiment, vulcanisation may be avoided and, optionally, glue may be used. The edges 18' may also comprise slots 28, as illustrated in FIG. 3, if a bending of the magazine strip is desired.

A further alternative is shown in FIG. 6. In this case, the strip 2 comprises edges 18" that are bent into en L- form on either side of a flat midpiece 21 in order to hold the polymer band 24. Also in this embodiment, vulcanisation may be avoided and, op- tionally, glue may be used. The edges 18" may also comprise slots 28, as illustrated in FIG. 3, if a bending of the magazine strip is desired.

A further alternative is shown in FIG. 7. In this case, the strip 2 comprises curved edge parts 29 on either side of a flat mid-piece 21 forming hollows 32, because the edge parts are curved to a degree, where the edges 31 have a mutual distance smaller than the width of the mid-piece 21. This way, the edge parts 29 accommodate the edges of the polymer band 24. Also, in this embodiment, vulcanisation may be avoided and, optionally, glue may be used. The strip 2 may comprise cut-outs in the form of holes 30 in the bent edges 29 as illustrated in FIG. 9. These holes 30 are provided mutually equidistant for cooperation with corresponding transport means in the power tool such that a safe and precise transport is achieved. If holes 39 are provided and no slots 28, the strip is stiff and can not be rolled onto a roll. Thus, the magazine strip would normally provided at a suitable length shorter than bendable strips, for example at a length of 20 cm to 50 cm, typically 25-30 cm. Alternatively, the edge parts 29 may also comprise slots 28, as illustrated in FIG. 3, if a bending of the magazine strip is desired. Composite washers are commercially available, where a polymer ring, typically HDPM rubber, is vulcanized onto a metal ring. The above embodiments provide the washers 5 as integrated parts of the strips 2. After driving-in the screws or nails into the underlying material causing removal of the washers 5 from the strip, the remaining part 25 of the strip 2 is normally discarded. In this connection, it is pointed out that the rubber is a relatively expensive material. In order to reduce the amount of rubber in the cavity 27 of the strip 2, the polymer band need not to extend to the edges 18, 29 of the strip 2 along its entire length. For example, it suffices to provide a band that only covers portions with the washers (5). This band could be a band with straight edges such that it has a constant width along it length. However, it may alternatively have a corrugated form, being narrower in the regions between the washers and wider at the locations of the washers. Optionally, at the location of the washers 5, it may extend to the edges 18, 29 for being hold by these, especially, if no glue is used to fix the polymer band 24 to the mid-piece 21.

Though the illustrated magazines only show three holes for driving-in elements, it is to be understood that the number of screws can take any arbitrary value. Typically, the magazines will have more than three holes for screws.