FR2929146A1

FR2929146A1 - Extractable screw or bolt head manufacturing method, involves producing tapered recesses at large quantities with embossments including embossment punches by using embossment transfer machine

Info

Publication number: FR2929146A1
Application number: FR0801622A
Authority: FR
Inventors: Jacques Henri Georges Lutrat
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-03-25
Filing date: 2008-03-25
Publication date: 2009-10-02
Anticipated expiration: 2028-03-25
Also published as: FR2929146B1

Abstract

The method involves producing tapered recesses at large quantities with embossments including embossment punches by using an embossment transfer machine. One of the punches is lowered to a level of a lower face of a mark to be realized on a head of a screw or bolt, where the punch includes a relief on a lower face of the punch corresponding to bottom of a groove. The punch has cuts (2) that are slanted on their external surfaces and vertical on their internal surfaces. The other punch is lowered at a level of an exterior surface of the head of the screw or bolt.

Description

Selon brevet N° FR2536478 (Al) publié le 25/05/1984 et intitulé Vis extractibles et tournevis adaptable non-ripant était présenté un nouveau type de vis dont la tête comportait, au lieu d'une simple rainure, une empreinte bien particulière constituée notamment de quatre petits retraits en biseau. Des modèles de telles vis ont pu être réalisés par électroérosion ce qui a permis de procéder à des essais qui ont donné entière satisfaction. Malheureusement cette méthode, trop onéreuse, n'a pas permis une commercialisation. According to patent No. FR2536478 (A1) published on 25/05/1984 and entitled Extractable screws and adaptable non-ripant screwdriver was presented a new type of screw whose head had, instead of a simple groove, a particular imprint consisting including four small recesses bevel. Models of such screws could be made by electroerosion which made it possible to carry out tests which gave complete satisfaction. Unfortunately this method, too expensive, did not allow a marketing.

Le but de la présente description est donc cle permettre la fabrication par grandes quantités et de façon très économique de vis ou boulons bénéficiant de ces caractéristiques particulières. A l'aide d'une machine-transfert de frappe, avec intervention de plusieurs frappes successives en continu, et avec utilisation de poinçons adaptés de forme décrite ci-dessous il est possible d'amener progressivement la tête des vis ou boulons à la forme requise en quelques étapes seulement. L'opération peut être menée à froid ou à chaud, selon la malléabilité du métal ou de l'alliage utilisé. Prenons par exemple ci-dessous une opération en trois étapes seulement : Le premier poinçon de frappe à utiliser (Fig. 1), adapté à la forme souhaitée selon qu'il s'agisse de vis ou boulons à tête plate, ronde, semi-ronde, hexagonale ou autre devra s'abaisser jusqu'au niveau de la face inférieure de l'empreinte (1-Fig.3 ,et Fig.4) à réaliser sur la tête de la vis et il comportera une surface correspondant au fond de la gorge souhaitée. Par ailleurs, il devra présenter quatre creux (2-Fig.1 et 2-Fig.2 montrant le poinçon vu du dessous), en biais sur leur face externe mais verticaux sur leur face interne et se terminant en pointe vers le centre du poinçon, régulièrement plus larges et plus profonds sur les bords et arrivant à une valeur nulle au centre de l'outil. The purpose of the present description is therefore to allow the manufacture in large quantities and very economically of screws or bolts benefiting from these particular characteristics. With the aid of a machine-transfer typing, with intervention of successive successive strikes, and with the use of suitable shaped punches described below it is possible to gradually bring the head screws or bolts to the shape required in just a few steps. The operation can be conducted cold or hot, depending on the malleability of the metal or alloy used. For example, consider below a three-step operation: The first punch punch to be used (Fig. 1), adapted to the desired shape for flat or round screws, bolts, semi- round, hexagonal or other shall be lowered to the level of the underside of the cavity (1-Fig.3, and Fig.4) to be made on the head of the screw and it will include a surface corresponding to the bottom of the desired throat. Moreover, it will have four cavities (2-Fig.1 and 2-Fig.2 showing the punch seen from below), obliquely on their outer face but vertical on their inner face and ending in a point towards the center of the punch , regularly wider and deeper on the edges and arriving at a zero value in the center of the tool.

Après la première frappe, la tête de vis en cours de fabrication (Fig.3) présentera donc un relief de 4 arêtes (3-Fig.3 et Fig.4 montrant la tête de vis vue du dessus). Le deuxième poinçon de frappe (Fig.5) ne devra plus s'abaisser que jusqu'au niveau de la surface extérieure de la tête de la vis ou du boulon à réaliser et cela qu'il s'agisse de vis à tête plate, ronde, semi-ronde, hexagonale ou autre, étant bien entendu que la forme de la base du poinçon devra correspondre à celle de la vis souhaitée. II ne devra plus comporter que quatre petits retraits (4-Fig.5 et Fig.6) en plans inclinés vers le centre de l'outil de telle façon qu'ils permettent de rabattre d'environ 45 degrés les quatre arêtes (5-Fig.7 et Fig.8) présentées par la tête de vis ou de boulon, après la première étape. Le troisième poinçon de frappe à utiliser (Fig.9 et Fig.10) ne présentera plus qu'une surface adaptée, sans relief particulier, et ne devra s'abaisser que jusqu'au niveau de la surface extérieure de la tête de la vis ou du boulon à réaliser. Il aura donc pour effet de terminer de rabattre les quatre arêtes au niveau de la surface de la tête de la vis (Fig.11 et Fig. 12) ou du boulon, réalisant ainsi les quatre retraits en biseau nécessaires (6-Fig.11 et Fig.12), pour être extractibles à l'aide de tournevis non-ripants ou d'embouts de perceuse visseuse ou de machines-outils ayant les mêmes caractéristiques requises. Remarques: Si l'on préfère procéder en quatre étapes, par exemple pour obtenir une meilleure finition, le poinçon de la deuxième étape sera conçu de façon à permettre de rabattre les quatre arêtes d'environ 30 degrés et un troisième poinçon permettra de les abaisser encore une fois de quelque 30 degrés supplémentaires avant que le quatrième poinçon, sans relief particulier, ramène les arêtes au niveau de la surface de la tête de la vis ou du boulon. After the first strike, the screw head being manufactured (Fig.3) will therefore have a relief of 4 edges (3-Fig.3 and Fig.4 showing the screw head seen from above). The second punching punch (Fig.5) shall be lowered only to the level of the outer surface of the head of the screw or bolt to be made and whether it is flat head screws, round, semi-round, hexagonal or other, it being understood that the shape of the base of the punch must match that of the desired screw. It should have only four small withdrawals (4-Fig.5 and Fig.6) inclined planes towards the center of the tool so that they can reduce by approximately 45 degrees the four edges (5- Fig.7 and Fig.8) presented by the screw or bolt head, after the first step. The third punching punch to be used (Fig. 9 and Fig. 10) will only have a suitable surface, without any particular relief, and must only be lowered to the level of the external surface of the head of the screw. or bolt to achieve. It will therefore have the effect of closing down the four edges at the surface of the head of the screw (Fig.11 and Fig. 12) or the bolt, thus achieving the four necessary bevel withdrawals (6-Fig.11). and Fig.12), to be extractable using non-razor screwdrivers or screwdriver bits or machine tools with the same characteristics required. Notes: If you prefer to proceed in four steps, for example to obtain a better finish, the punch of the second step will be designed so as to fold the four edges of about 30 degrees and a third punch will lower them again a further 30 degrees before the fourth punch, without any particular relief, brings the edges back to the surface of the head of the screw or bolt.

On pourrait tout aussi bien imaginer des têtes de vis sur lesquelles apparaîtraient non pas deux demi-rainures spéciales dans le prolongement l'une de l'autre mais par exemple trois décalées de 120° l'une par rapport à l'autre. Dans ce cas la lame du tournevis adapté comporterait non pas deux mais trois demi-reliefs à 120° l'un de l'autre. Ou bien prévoir au centre de la tête des vis un petit creux en forme de cône inversé dans lequel viendrait se loger un cône en relief et complémentaire dont la lame du tournevis serait munie en bout et en son centre. II ne semble pas toutefois que de telles modifications du système puissent apporter un avantage décisif. One could just as easily imagine screw heads on which would appear not two special half-grooves in the extension of one another but for example three shifted by 120 ° relative to each other. In this case the blade of the adapted screwdriver would include not two but three half-reliefs at 120 ° from each other. Or to provide in the center of the head of the screw a small hollow inverted cone in which would be housed a cone in relief and complementary whose blade of the screwdriver would be provided at the end and in its center. It does not appear, however, that such changes in the system can provide a decisive advantage.

Claims

CLAIMS1) A method for the simple and economical manufacture of screw heads or extractable bolts, said head having a particular imprint consisting in particular of four small recesses in bevels and not a simple groove, characterized in that the production in large quantities and for an acceptable cost price is obtained using a typing machine-transfer equipped with punches.

2) Method according to claim 1 characterized in that the bevel withdrawals are obtained in several successive strikes, preferably three strikes, the first punch (Fig.1 and Fig.2) having to lower to the level the bottom face of the footprint to be made on the heads of screws or bolts and whether it is flat heads, round, semi-round hexagonal or other.

3) Method according to one of claims 1 or 2, characterized in that the first punching punch comprises on its underside a relief corresponding to the bottom of the desired groove and has four recesses (2-Fig.1 and Fig.2 ) skewed on their outer face but vertical on their inner face and ending in a point towards the center of the punch, regularly wider and deeper on the edges and arriving at a zero value towards the center of the tool.

4) Method according to one of the preceding revendicatiors, characterized in that the second punching punch (Fig.5 and Fig.6), is lowered to the outer surface of the screw head or the bolt to perform, and has only four small withdrawals to reduce by approximately 45 ° the four edges that have the heads of screws or bolts after the first strike.

5) Method according to one of the preceding claims, characterized in that the third punch has at its base a smooth surface, without hollow or particular relief, but only adapted to the shape of the screw head or bolt in progress, lowers to the outer surface of the head of the screw or bolt and ends up folding the four edges at this surface.

6) Method according to one of the preceding claims characterized in that it allows to produce elements that have withdrawals, so impossible to obtain in a single strike, with the use of punches such as to gradually fold edges or protuberances in several successive strikes.