PRODUCING MACHINE

FIELD OF THE INVENTION

The present invention relates to a conveying mechanism for a nail producing machine comprising a plurality of rotatable cylinders for conveying an elongated member; and one of the rotatable cylinders being a driving cylinder rotated by a drive mechanism; wherein the driving cylinder is connected with at least one of the other rotatable cylinders via a drive belt. BACKGROUND OF THE INVENTION

Modern nail producing machines, such as high-speed rotary wire nail machines, are capable of producing large quantities of nails from metal wires. The metal wire is cut into a plurality of elongated metal objects that are formed into finished nails.

Production speed and reliability are two important properties of a nail production machine. High production speed is desirable as the value of the machine depends on the machine's expected production capabilities; and reliability is important, as a malfunctioning machine is costly both in direct reparation costs and in lost production.

In a high-speed rotary wire nail machines the metal wire is cut into appropriate pieces of a desired length, which are then feed into dies arranged on a rotating tooling ring by a feeding mechanism. The feeding mechanism is adapted to convey pieces of metal wire from the cutting station into the dies. Traditionally such feeding mechanism comprises a plurality of rotating cylinders that engages with the pieces of metal wire. One rotating cylinder is often driven by a drive mechanism and rotational forces are transferred from this cylinder to the other cylinders via drive belts. These drive belts are a crucial wearing part than needs to be exchanged frequently to prevent machine breakdown.

The feeding mechanism operates at high speeds of approximately 4000 RPM and the operating environment is harsh, including amongst others flying metal fragments resulting from the cutting process. The drive belts are constantly bombarded by these metal fragments and due to the high operating speed, operating temperatures are high. These factors result in known drive belts being significantly worn after a few hours, which affects the operation of the machine. A worn drive belt may result in uneven machine operation, which again may cause machine breakdown.

Traditional drive belt are manufactured from length of material glued together to provide a belt. Due to amongst others the glue connection, such drive belts does not have constant material properties and physical characteristics along the length of the belt, resulting in an uneven transfer of forces. Further, the material traditionally used is a layered material, which is quite sensitive in terms of notch fractures caused by wear and in particular, the flying metal fragments.

As the existing feeding mechanism are known to be somewhat unreliable, requiring frequent exchange of wearing parts, such as drive belts, it would thus be advantageous to be able to provide a nail producing machine and an associated feeding mechanism that is both fast and reliable without significantly increasing the production costs of the machine itself. SUMMARY OF THE INVENTION

It is an object of the present invention to wholly or partly overcome the above disadvantages and drawbacks of the prior art. More specifically, it is an object to provide a feeding or conveying mechanism for a nail producing machine that is both fast and reliable. More specifically, it is an object to provide a drive belt for rotating rotatable rollers of a conveying mechanism for a nail producing machine. Thus, the above described object and several other objects are intended to be obtained.

In a first aspect, the invention provides a drive belt for rotating rotatable rollers of a conveying mechanism as described above, the drive belt comprising : a main body having an outer surface extending along its outer periphery and a

substantially planar contact surface positioned along its inner periphery, wherein the main body is constituted by a monolithic element of a polymer material, the polymer material being hydrolysis resistant polyurethane, and wherein a cross- section of the main body is solid and uniform along the entire length of the drive belt.

An advantage of having a drive belt having a monolithic and uniform both is that the material properties of the drive belt are uniform along the entire length of the drive belt. Hereby the power transmission is constant and the machine operation becomes smoother. An associated advantage in this regard is that the operation speed of the machine can be increased. Tests have shown that the endless drive belt has a lifetime of approximately 5 times that of the prior art glued drive belt under normal nail production conditions in a nail producing machine.

Further, the endless drive belt provides a more even transfer of drive forces, i.e. a more uniform drive is provided. Still further, due to the more uniform drive, the conveying mechanism of the nail producing machine will provide a lower vibration level and a lower noise level than what can be obtained with prior art drive belt. By 'substantially plane' is understand a surface which may have profiles or grooves or cuts to improve grip to the surface of the rotatable cylinders, compared to a completely plane surface.

In an embodiment, the invention provides a drive belt for rotating rotatable rollers of a conveying mechanism for a nail producing machine, the conveying

mechanism comprising : a plurality of rotatable cylinders for conveying an elongated member; and one of the rotatable cylinders being a driving cylinder rotated by a drive mechanism; wherein the driving cylinder is connected with at least one of the other rotatable cylinders via a drive belt, the drive belt being constituted by a main body being a monolithic element of a uniform polymer material providing an endless drive belt.

The invention is particularly, but not exclusively, advantageous for obtaining a conveying mechanism wherein the drive belt is more robust whereby the nail producing machine becomes more reliable and less maintenance work is required. The drive belt may have a planar contact surface, or at least a substantially plane surface, positioned along an inner periphery of the main body. Hereby a smooth drive can be obtained. However, it may be preferred that the drive belt has a substantially planar contact surface positioned along an inner periphery of the main body, wherein said substantially plane contact surface has distributed profiles, such as cuts or grooves, so as to improve a contact with a surface of the rotatable cylinder.

By 'substantially planar' with 'distributed profiles' is understood a contact surface which is mainly planar, but which has distributed profiles, such as indentations or cuts or grooves on it. E.g. 90%-99% of the contact surface may be a planar surface, and the remaining 1-10% may be protruding from the surface or may have been removed from the surface, the latter being the case of a cut or groove. In a second aspect, the invention provides use of the drive belt according to the first aspect for rotating rotatable rollers of a conveying mechanism of a nail producing machine.

In a third aspect, the invention provides a method for manufacturing an endless drive belt for rotating rotatable rollers of a conveying mechanism for a nail producing machine, the method comprising

- providing a monolithic polymer material, the polymer material being hydrolysis resistant polyurethane, and

- forming a main body with a solid and uniform cross-section along its entire length from the monolithic polymer material, such as comprising a moulding process or comprising a drilling or milling process.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

It is to be understood that the mentioned aspects and embodiments thereof may be combined in any way. BRIEF DESCRIPTION OF THE FIGURES

The conveying mechanism and drive belt according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

Figure 1 shows a schematic drawing of the conveying mechanism seen from above,

Figure 2 shows a schematic drawing of the same conveying mechanism seen from the side,

Figure 3 shows a drive belt, and

Figure 4a-4c show cross-sections of different embodiments of a drive belt. DETAILED DESCRIPTION OF AN EMBODIMENT

Fig. 1 shows a conveying mechanism for a nail producing machine comprising a plurality of rotatable cylinders 2 for conveying elongated members. One of the rotatable cylinders is a driving cylinder 3 that is rotated by a drive mechanism (not shown). The driving cylinder is connected with another rotatable cylinder via a drive belt 4 as shown in Fig. 2, whereby rotational forces are transferred from the driving cylinder 3. As shown in Fig. 2 the other rotating cylinders are rotated according to a similar principle by additional drive belts connected to the first rotating cylinder driven by the driving cylinder. Alternatively, the other rotating cylinders may be connected directly to the driving cylinder via drive belts.

The drive belt shown in Fig. 3 is constituted by a main body 41, which is a monolithic element of a polymer material. Preferable, the polymer material may be hydrolysis resistant polyurethane, which is very wear resistant. Further, a cross-section of the main body is solid and uniform along the entire length of the drive belt. This provides a drive belt with constant material properties and physical characteristics along the entire length of the drive belt, whereby power transmission becomes smoother.

Compared to traditional drive belts, these characteristics provide a wear resistant and durable drive belt. Previously, drive belts of the dimensions used in a conveying mechanism according embodiments of the present invention have not been made from a polymer material, more specifically hydrolysis resistant polyurethane. The drive belt may be manufactured in a moulding process or in a drilling or milling process.

The drive belts of the conveying mechanism are adapted to drive at speeds between 3000 and 5000 revolutions per minute. Further, the drive belts are quite small with lengths from 50-100 millimetres and bending sections 42 of the drive belts, adapted to fit the size of the rotatable cylinders, having a radius from 5-25 mm.

Further, the drive belt has a substantially planar contact surface 43 positioned along an inner periphery of the main body and outer edges 44 are positioned along an outer periphery 45 of the drive belt. As shown in Fig. 4b and 4c these outer edges may be rounded or bevelled. By rounding the outer edges durability is improved as creation of notches is reduced.

To provide a better grip, grooves or cuts may be provides on the inner surface of the drive belt. Such grooves or cuts may be formed in the drilling or milling process of manufacturing the drive belt.

Still further, one or more inner edges 46 of the drive belt positioned along the contact surface may be rounded or bevelled as shown in Fig. 4c. Rounding the inner edges eases mounting of the belts on the cylinders.

The invention will now be described by various embodiments thereof: El . A conveying mechanism (1) for a nail producing machine comprising : - a plurality of rotatable cylinders (2) for conveying an elongated member, and

- one of the rotatable cylinders being a driving cylinder (3) rotated by a drive mechanism, wherein the driving cylinder is connected with at least one of the other rotatable cylinders via a drive belt (4), the drive belt being constituted by a main body (41) being a monolithic element of a uniform polymer material providing an endless drive belt.

E2. Conveying mechanism according to El, wherein the polymer material is hydrolysis resistant polyurethane.

E3. Conveying mechanism according to El or E2, wherein polymer material of the main body is uniform along the entire length of the drive belt thereby providing a drive belt with substantially constant material properties and physical

characteristics along the entire length of the drive belt.

E4. A conveying mechanism according to any of E1-E3, wherein the drive belt is adapted to drive the rotatable rollers at speeds between 3000 and 5000 revolutions per minute.

E5. Conveying mechanism according to any of E1-E4, wherein the length of the drive belt is from 50-100 millimetres, and wherein the bending sections (42) of the drive belt has a radius (r) from 5-25 mm, when mounted for operation in the nail producing machine.

E6. Conveying mechanism according to any of E1-E5, wherein one or more outer edges (44) of the drive belt positioned along an outer periphery (45) of the drive belt are rounded or bevelled

E7. Conveying mechanism according to any of E1-E6, wherein one or more inner edges (46) of the drive belt positioned along the contact surface are rounded or bevelled. E8. Conveying mechanism according to any of E1-E7, wherein the drive belt has a planar contact surface (43) positioned along an inner periphery of the main body.

E9. Conveying mechanism according to any of E1-E8, wherein the drive belt has a substantially planar contact surface (43) positioned along an inner periphery of the main body, wherein said substantially plane contact surface (43) has distributed profiles, such as cuts, so as to improve a contact with a surface of the rotatable cylinder. E10. A drive belt for rotating rotatable rollers of a conveying mechanism for a nail producing machine, the drive belt comprising

- a main body having an outer surface (41) extending along its outer periphery and a substantially planar contact surface (43) positioned along its inner periphery, wherein the main body is constituted by a monolithic element of a polymer material and wherein a cross-section of the main body is solid and uniform along the entire length of the drive belt.

El l . Drive belt according to E10, wherein the length of the drive belt is from 50- 100 milimeters, and wherein bending sections (42) of the drive belt has a radius from 5-25 mm. E12. Drive belt according to any of E10-E11, wherein the drive belt has a planar contact surface (43) positioned along an inner periphery of the main body.

E13. Drive belt according to any of E10-E11, wherein the drive belt has a substantially planar contact surface (43) positioned along an inner periphery of the main body, wherein said substantially plane contact surface (43) has distributed profiles, such as cuts, so as to improve a contact with a surface of the rotatable cylinder.

E14. A use of the drive belt according to any of E10-E13 for rotating rotatable rollers of a conveying mechanism of a nail producing machine. E15. A method for manufacturing an endless drive belt for rotating rotatable rollers of a conveying mechanism for a nail producing machine, the method comprising

- providing a monolithic polymer material, and

- forming a main body with a solid and uniform cross-section along its entire length from the monolithic polymer material, such as comprising a moulding process or comprising a drilling or milling process.

Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.