MXPA98009621A - Fixing screw and method for your manufacture - Google Patents

Abstract

The present invention relates to a fastening screw for fastening metal foil in wood, comprising an elongated spike, and a punching tip and a head provided at respective opposite ends of the spike, where the spike is tapered towards the punching point, where the piercing tip has a pair of cutting edges disposed on opposite sides of the longitudinal axis of the pin defining a cutting edge functional to cut through the metal sheet, and grooves which respectively extend longitudinally of the pin from each of the edges cutting, where a string is formed on the spike and extending from a point adjacent to the punching point back and beyond the section of the spike where the splines are formed, where the punching tip ends in a pair of sloping end surfaces which intersect each other at a tip end in the form of a linear intersection extending erpendicular to the longitudinal axis of the spike, where each cutting edge of a flute ends at a point at a lower extent of the edge, where the points establish opposite ends of the intersection line

Description

-t FASTENING SCREW AND METHOD FOR ITS MANUFACTURE FIELD OF THE INVENTION The present invention relates to fastening screws of the auto-adjusted and self-tapping type, which has a piercing tip at the end end of the threaded pin. BACKGROUND OF THE INVENTION Clamping screws of the prior art type are produced in various ways and, generally, these various forms are adopted for introduction into metal and wood, respectively. The clamping screws, which are try to enter through a sheet of metal, they have a piercing point that has substantially the same characteristics, in terms of form and function, as the end of the conventional piercing fragment for metal penetration (see attached Figures 1 and 2). ). The The end portion of the clamping screw, in which the piercing tip is formed, is not threaded and is very similar to the conventional drilling fragment, except that the flutes are straight instead of spirally shaped. The length of the end portion without thread varies, but is generally significantly greater than the diameter of this portion. The clamping screw, which is intended to be used for penetration into wood, has fragments for completely different penetration, a typical example of which is shown in Figures 3 and 4. The main feature of the wood screw is that it has a portion tapering end which ends at a pointed end end, and the thread or cord extends along the end portion, substantially to the end or tip end. Also, a simple channel is provided in the piercing tip instead of two, as in the case of screw clamps that are tried to be used to introduce them through a sheet of metal. The continuation of the thread through the end portion is an important aspect, since it allows the thread to penetrate the wood, in advance, in the process of introduction and therefore pushes the screw into the wood. This reaction between the thread and the wood assists in the drilling operation since it requires extreme minimum pressure in the fastener. The problem arises when a fastening screw designed to penetrate the metal is required to be inserted into wood, for example when the screw is used to fasten a sheet of metal on a wooden support. Typically, under these circumstances the screw penetrates into the metal sheet as in the wood without difficulty, until the threaded portion of the pin of the fastener reaches the surface of the wood. The rope is not inserted into the wood as with the fastener of Figures 3 and 4, but tends to slide on the surfaces of the wood. Then, an additional final force is required to introduce the fastener into the wood and achieve a self-tapping without removing the internal cord that was already formed. It is not an uncommon problem, for traders, that a screw is needed to penetrate a metal sheet and attach it to a wooden support, of the type shown in Figures 3 and 4. Substantial, final force is required initiate the penetration through the metal, but a smaller effort for the penetration and tapping into the wood, for the reason specified above. The puncture tip of these fasteners is not suitable for cutting metal and tends to leave burrs as it penetrates through the metal sheet. These burrs are not appreciable and are dangerous thanks to their jagged nature. It also promotes the corrosion of the metal sheet and tends to cause leaks in the roof, since due to the burrs it is not allowed that the sealing washer is placed firmly against the surface of the roof.

OBJECTIVES OF THE INVENTION An object of the present invention is to solve or minimize the aforementioned difficulties by providing a clamping screw which cuts neatly through the metal and which requires a minimum insertion force to form a coupling thread in the wood. Another object of the invention is to provide an improved method and apparatus for forming a fastening screw.

SUMMARY OF THE INVENTION According to the present invention, there is provided a fastening screw having an elongated spike, and a piercing tip, as well as a head provided at the respectively opposite ends of the spike, this piercing tip has an edge cutting to pass through the metal and a channel extending longitudinally with respect to the spike, forming a thread or rope in the spike and extending in the portion of the section of the spike in which the channel is formed. The drill tip is designed to efficiently cut into the metal and to collect and remove the chip that forms during the penetration of the drill tip into the metal and wood component. Preferably, the thread formed in the spike extends into a substantial portion of the portion of the spigot in which the channel was formed. It is preferred that the grooved portion of the spike be taut so that, generally, it has a frusto conical shape. It is preferred that the cutting edge of the piercing tip extends outwardly from the axis of the shank and angularly towards the end of the head of the shank, while the channel extends from the cutting edge towards the end of the head of the spike. Preferably, the spike has a parallel portion and a tapered portion, which is adjacent to the respective head of the piercing tip of the fastener, the channel extends at least along a wall of the tapered portion, and the cord is formed in the spike, so that it extends both along the parallel portion and the tapered portion of the spike. It may be that the rope does not extend over the entire length of any of the portions of the spike, but preferably extends at least along a portion of the tapered portion. It is further preferred that the rope extends without interruption through the joint between the two portions of the spike. Preferably, the piercing tip includes two cutting edges and two channels, each extending longitudinally from the respective cutting edge. Each cutting edge can be placed on the corresponding one, of the two opposite sides t of the spindle axis, and, generally, each can be arranged and arranged angularly in the same way corresponding to the cutting edges of the conventional drilling fragment. to penetrate through the metal. According to one aspect of the invention, there is provided a method for forming a clamping screw from a previously formed screw, having an elongated, cylindrical pin and a head at one end of the pin, including the deformation passages. of this preform by the operation of moving the material to create a piercing tip on the end portion of the spike opposite the head, this piercing tip has at least one cutting edge to penetrate through the metal and a channel that It extends from the edge to the head, applying the cord to this spike that extends into the portion of the section of the spike in which the channel is formed. The end portion of the spike remote from the head may be subjected to a punching, forging or other operation of moving the material to create a piercing tip configuration having at least one angularly arranged cutting edge and a channel which extends from the cutting edge towards the end of the head of the spike. A portion of the waste material may extend between the cutting edge and the terminal end of the previously formed peg, and this waste may be removed in a suitable manner to leave the exposed cutting edge at the terminal end of the peg, which is create in this way. The rope or thread may be formed in the spike after or during the removal of the aforementioned waste material, and it is preferable that the winding operation of the rope be used for this purpose. further, the present invention provides a die for the formation of a threaded fastener screw of the type described above, from a previously formed screw, which has a cylindrical elongate pin and a head at one end of this pin, by means of a rope twisting operation, this die includes a ramp or slope surface to remove a portion of the tang material from the terminal end of the shank opposite the head, to expose a cutting edge. It is further preferred that each thread for screwing the rope is formed in such a way that the portion of the peg adjacent to the cutting edge of the piercing tip is made with an inclination in order to reduce the diameter (or the cross size) in a direction away from the head of the bra. This inclined portion includes at least a part of the channel of the piercing tip.

Preferably, the thread or rope extends, at least substantially along the portion of the tapered portion, so as to terminate, in closure, the cutting edge of the piercing tip. The formation of the tapered portion and / or the thread in this portion can result in a removal of the outer portion of the cutting edge at the piercing tip as it was originally formed, but the internal portion (i.e. the adjacent axis of the cut). spike) of the cutting edge remains intact. In addition, the formation of the tapered portion through the plastic deformation of the pin displaces the material in such a way as to lengthen, axially, the pin, and it is preferred that the machinery be constructed or arranged in a way that allows the stretching to be done without interruptions so that the aforementioned internal portion of the cutting edge is not distorted. It is considered convenient to describe the invention mentioned in more detail, with reference to the accompanying drawings, which show an embodiment of the invention. The particularity of the drawings and the associated description should not be considered as a substitution of the general aspect of the previous description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Figure 1 is a side view of the piercing tip of a fastening screw according to the prior art. Figure 2 is a final view in the lili direction of the piercing tip of Figure 1. Figure 3 is a side view of the piercing tip of a holding screw according to the prior art. Figure 4 is a final view in the IV-IV direction of the piercing tip of Figure 1. Figure 5 shows a clamping screw according to an embodiment of the invention. Figure 6 is a final view in the VIVI direction of a fastening screw of Figure 5. Figures 7 to 10 illustrate, in diagram form, the steps of the method for forming a fastening screw in accordance with an embodiment of the invention. Figure 11 shows a punch for screwing the rope that is used in the formation of a clamping screw according to Figures 7 to 10.

Figure 12 is a cross-sectional view of the die for screwing the rope of Figure 11 through the line XII-XII.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION Figures 5 and 6 show an embodiment of a fastening screw incorporating an example of the embodiment of the invention. It is understood that the invention is applied to fastening screws substantially different from the screw shown in Figures 5 and 6. In the example shown, the fastener includes an elongated pin 1.and a piercing tip 2, as well as a head 3, located at the respective opposite ends of the pin 1. The pin 1 includes a parallel portion P and a tapered portion T disposed at one end as shown. The tapered portion T is reduced in diameter in the direction away from the head of the fastener 3, and may have a length selected to suit the circumstances of use of the fastener. The degree of reduction can be larger or smaller according to the requirements, but in any case, it is such that the tapered portion T has frustoconical shape. It is understood that the tapered portion T may be omitted in other embodiments of the invention.

The piercing tip 2 is formed at a final end of the pin 1, and in the example shown includes two cutting edges 5, which are located on the respective opposite sides of the spindle axis. Each cutting edge 5 extends angularly outwardly from the spindle axis, so as to be inclined towards the head of the fastener 3. The angle of inclination of each edge 5 can be substantially the same as that adopted for the corresponding edges in the cutting end of a conventional drilling fragment of the type that is designed to pass through metal. Each cutting edge 5 is created by forming a channel 6 through the inclined end surface 7 of the spike 1. As will be readily appreciated from Figure 5, each channel 6 extends from the respective cutting edge 5 is a general direction of the longitudinal axis of the pin 1, and extends at least part of the length of the axis of the tapered portion T. It is preferred, as shows, that the end surface 7 of the pin 1 is immediately adjacent to the smaller diameter end of the tapered portion T. The thread or thread 8 is formed in the pin 1 and extends, at least, along a part of the length of each portion of the pin P and T. It is preferred that the thread or string 8 extends over a substantial portion of the tapered portion T, so as to end adjacent to the end surface 7. It is also preferred that the depth of the thread 8 is reduced, progressively, as it approaches the end of the surface 7, thus providing a guide to the rope for the tapping. Any suitable method can be adopted to produce a fastener of the type described above. Figures 7 and 10 illustrate, in diagram form, several stages in the formation of the fastener by an example method. Figure 7 illustrates a pre-formed fastener 9 having an elongated cylindrical pin 1 and a head 3 at one end of the spike 1. The configuration of the piercing tip 10 (Figure 8) is formed in the spike 1, adjacent the final end 11, preferably by a process of punching, forging or any other operation for the movement of the metal. The configuration 10 is such that each cutting edge 5 is created, as well as each associated channel 6 and the inclined end surface 7, through which the channel 6 extends. There is a portion of waste material 12 in the part right of surface 7, as shown in Figure 8, t this portion 12 can be removed in any suitable manner to leave surface 7 and edges 5 exposed at a recently created end end of spigot 1, as shown in Figure 9.

Rope 8 can be formed in pin 1 by any suitable method, but it is preferred to use a rope twisting process. For this purpose, the threading screw of the rope 13 can be used, as shown in Figures 11 and 12. The thread screwing process is well known and it is not necessary to explain it in more detail in the present specification. However, in the preferred form of the method, the die 13 is arranged to create the special features of the fastener as explained above. The die 13 may include a ramp 14 which operates to remove the waste portion 12 in the known manner during or before starting the thread or rope forming operation. In addition to the formation of the rope, the die 13 is constructed, preferably to create a tapered portion Y by the plastic deformation of the previously formed peg 1. This deformation step may be carried out coinciding or during the rope forming step, and it is preferred that the rope 8 be extend, at least, substantially along a portion of the tapered portion T, as shown in Figure 10. The formation of the tapered portion T by plastic deformation, of course, causes an axial stretching of the pin 1, and it is necessary to ensure that this stretching does not result in the total destruction of the basic configuration of the piercing tip 2, as created in the step of Figure 9. For this purpose, it is preferred that the die for screwing the rope 13 be constructed suitably and related to the length of the previously formed spindle shaft 1 to prevent distortion, at least a part of the end surface 7 during the aforementioned stretch the tang. In the preferred form of the method that is achieved by forming the die 13, so that a spacing is retained.

(Figure 9) on the surface 7, as the stretching of the spigot 1 occurs. The dotted lines 15 shown in Figure 9 represent the surface of the die 13, which produces a portion of the tapered spike T. As will be apparent from looking at Figure 8, the particular method that was described results in the destruction of the outer, radial portion 7a of the surface 7, as it is formed and the stage shown in Figure 8 is completed. In this process the corresponding portion of each cutting edge 5 will also be destroyed. On the other hand, the radial inner portion of the surface 7, and the corresponding portion of each edge 5, they remain intact after the step described in Figure 10 is completed. The remaining portion of each edge 5 is a functional cutting edge of the piercing tip of the fastener which is finally formed. The fastener according to the present invention has a piercing tip that is essentially a hybrid of the piercing tips of two prior art fasteners, according to Figures 1 through 4. The new drill tip retains the desirable characteristics of each of the prior art drill tips. In particular, it is ideally suited for penetrating either metal or wood since it retains the general characteristics of the drill tip of Figures 1 and 2, and allows the fastener to be driven into the wood with minimal effort, thanks to the portion of the tapered end and the arrangement of the rope, at least, substantially along the portion of the tapered portion. Other benefits of the new fastener will be apparent to those skilled in the relevant art. Finally, it is understood that the various alterations, modifications and / or additions can be introduced in the construction and arrangements of the parts described above without departing from the spirit and scope of the invention.

Claims (19)

1. A clamping screw - having an elongated pin, and a piercing tip, as well as a head that is placed on the respective, opposite ends of the pin, the piercing tip has a cutting edge to penetrate through the metal and a channel extending longitudinally to the spigot, a thread which is formed in the spigot and extends in the portion of the spigot section in which the channel is formed.

2. The clamping screw according to claim 1, wherein the cord or thread extends into the substantial portion of the section of the pin in which the channel is formed.

3. The clamping screw according to claim 1 or 2, wherein the cutting edge extends outward from the longitudinal axis of the pin and angularly towards the end of the head of the pin.

4. The clamping screw according to any one of claims 1 to 3, wherein the channel extends, longitudinally, from the cutting edge of the pin, towards the head thereof.

5. The clamping screw according to any one of claims 1 to 4, wherein the spike has a parallel portion and a tapered portion extending, respectively, from the head and piercing tip, this channel extends, at least, along the section of the tapered portion and the thread formed in the spike to extend, at least, along the length of the tapered and parallel portions.

6. The clamping screw according to claim 5, wherein the rope extends, substantially, along a portion of the length of the tapered portion.

7. The clamping screw according to claim 5 or 6, wherein the cord extends through the joint between the parallel and tapered portions, without interruption.

8. The clamping screw according to claims 4 to 7, wherein the cutting edge includes two cutting edges and two channels, each channel extending from the respective cutting edge, longitudinally to the pin towards the head thereof .

9. The clamping screw according to claim 8, wherein each cutting edge is positioned on the opposite side, respectively, of the longitudinal axis of the pin.

10. The clamping screw according to any one of claims 1 to 9, wherein the depth of the rope is reduced as it is directed towards the end of the piercing tip of the spike.

11. The clamping screw according to any of claims 1 to 10 and which is formed by a die-cutting or forging process.

12. The method of forming the clamping screw from a preformed screw, having an elongated, cylindrical pin and a head at one end of the pin, including the deformation steps of the previously formed screw, by means of the movement operation of the material to create a piercing tip at an end portion of the spike, opposite the head, the piercing tip has at least one cutting edge to penetrate through the metal and a channel extending from the rim towards the head , by applying a rope to the spike, which extends into the portion of the section of the spike in which the channel is formed.

13. The method according to claim 12, wherein the portion of the tang material extending between the cutting edge and the terminal end of the opposite head of the preformed screw is removed to expose the cutting edge and to form a cutting edge as a terminal end of the fastener.

14. The method according to claim 13, wherein the rope is formed either during or after removal of the portion of the spike material.

15. The method according to any of claims 12 to 14, in which the rope or thread is formed by a rope twisting operation, in which a rope twisting die is used, in which each die for screwing of the rope is formed to apply a trellis on the end portion of the spike, opposite the head, this rope is reducing its diameter as it moves away from the head and forms along the section of the final portion , which includes, at least, a part of a channel.

16. The method according to any of claims 12 to 15, the method includes the removal of an outer portion of at least one cutting edge from the piercing tip to leave an inner portion of this edge intact.

17. The method according to any of claims 15 or 16, wherein the method allows an axial stretching of the pin under an operation of moving the material to form this conical shape.

18. The method according to any of claims 12 to 17, wherein the operation of moving the material comprises a punching or forging operation.

19. The die for forming the threaded fastening screw according to any of claims 1 to 11, from a pre-formed screw, which has an elongated, cylindrical spike and a head at one end of the spike , by means of the twisting operation of the rope, this punch includes a ramp surface to remove a portion of the material from the spike from the end of the spike opposite the head, to expose a cutting edge.