HIGH-STRENGTH LIGHTWEIGHT SCREW HAVING A DOUBLE CONTOUR ENGAGEMENT

Abstract

A high-strength screw (1) includes a head (2) having a tool engagement external contour (7) and a tool engagement internal contour (8). For example, the tool engagement external contour (7) is an external hexagonal and the tool engagement internal contour (8) is an internal hexagonal. A plurality of additional pocket-shaped impressions (13) are arranged in the tool engagement internal contour (8) between corners (12).

Claims

1. A high-strength screw, comprising: a head, the head having a tool engagement external contour, and a tool engagement internal contour, the tool engagement internal contour including a plurality of force engagement surfaces and a plurality of corners, the corners being arranged between the force engagement surfaces; and a plurality of pocket-shaped impressions, the pocket-shaped impressions being arranged in the tool engagement internal contour, the pocket-shaped impressions not being the force engagement surfaces.

2. The screw of claim 1, wherein the pocket-shaped impressions are arranged approximately centrally between the corners.

3. The screw of claim 1, wherein the screw includes a shank; the head has a first axial end facing from the shank; and the pocket-shaped impressions are located next to the first axial end of the head.

4. The screw of claim 1, wherein the pocket-shaped impressions are designed as cold-formed dents being located in one of the force engagement surfaces of the tool engagement internal contour.

5. The screw of claim 1, wherein the screw includes a shank; the head has a first axial end facing from the shank; and the pocket-shaped impressions have a width, the width increasing in a direction towards the first axial end of the head.

6. The screw of claim 1, wherein each of the force engagement surfaces has a width; and the pocket-shaped impressions do not extend over the entire width of the force engagement surfaces.

7. The screw of claim 1, wherein the tool engagement internal contour belongs to one of the following geometry types: multi-edge, multi-tooth and multi-round.

8. The screw of claim 1, wherein the tool engagement internal contour belongs to one of the following geometry types: six-edge, four-tooth and six-round.

9. The screw of claim 1, wherein the tool engagement internal contour belongs to one of the following geometry types: multi-edge and multi-tooth; and the pocket-shaped impressions of the tool engagement internal contour are arranged approximately centrally between the corners of the multi-edge or multi-tooth.

10. The screw of claim 1, wherein the tool engagement internal contour belongs to the geometry type multi-round; the force engagement surfaces and the corners of the tool engagement internal contour are rounded; and the pocket-shaped impressions are arranged approximately centrally between the rounded corners of the multi-round.

11. The screw of claim 1, wherein the tool engagement external contour belongs to one of the following geometry types: multi-edge, multi-tooth and multi-round.

12. The screw of claim 1, wherein the tool engagement external contour belongs to one of the following geometry types: six-edge, twelve-edge, twelve-tooth and six-round.

13. The screw of claim 1, wherein the tool engagement external contour belongs to one of the following geometry types: multi-edge and multi-tooth; the force engagement surfaces of the tool engagement external contour being plane; and the pocket-shaped impressions are arranged approximately centrally between the corners of the multi-edge or multi-tooth.

14. The screw of claim 1, wherein the tool engagement external contour belongs to the geometry type multi-round; the force engagement surfaces and the corners of the tool engagement external contour are rounded; and the pocket-shaped impressions are arranged approximately centrally between the rounded corners of multi-round.

15. The screw of claim 1, wherein the tool engagement external contour and the tool engagement internal contour belong to the same geometry type.

16. The screw of claim 15, wherein the geometry type is one of the following: edge, tooth and round.

17. An automatic deforming method for manufacture of a high-strength screw from a blank, comprising the steps of: deforming the blank in a deforming tool such that a head of a screw having a tool engagement external contour, a tool engagement internal contour, the tool engagement internal contour including a plurality of force engagement surfaces and a plurality of corners, the corners being arranged between the force engagement surfaces, and a plurality of pocket-shaped impressions, the pocket-shaped impressions being arranged in the tool engagement internal contour, the pocket-shaped impressions not being the force engagement surfaces are produced.

18. The deforming method of claim 17, wherein the blank is deformed by cold-forming such that the screw attains the features of at least one of the preceding claims.

19. A deforming tool for manufacture of a high-strength screw of a blank, comprising: a stamp tool; and a matrix tool, the stamp tool and the matrix tool being designed and arranged such that they, when the deforming tool is actuated, deform the blank in a way that a head of a screw having a tool engagement external contour, a tool engagement internal contour, the tool engagement internal contour including a plurality of force engagement surfaces and a plurality of corners, the corners being arranged between the force engagement surfaces, and a plurality of pocket-shaped impressions, the pocket-shaped impressions being arranged in the tool engagement internal contour, the pocket-shaped impressions not being the force engagement surfaces are produced.

20. An actuation tool for actuating a high-strength screw having a tool engagement external contour and a tool engagement internal contour, comprising: an external actuation element for engaging the tool engagement external contour of the head of the screw; and an internal actuation element for simultaneously engaging the tool engagement internal contour of the head of the screw.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In the following, the invention is further explained and described with respect to preferred exemplary embodiments illustrated in the drawings.

[0057] FIG. 1A illustrates a perspective view of a first exemplary embodiment of the new screw having a double contour engagement.

[0058] FIG. 1B illustrates a view of the head of the screw according to FIG. 1A from above.

[0059] FIG. 1C illustrates a partial sectional side view of the screw according to FIG. 1A.

[0060] FIG. 1D illustrates the detail A of FIG. 1C.

[0061] FIG. 2A illustrates a perspective view of a second exemplary embodiment of the new screw having a double contour engagement.

[0062] FIG. 2B illustrates a view of the head of the screw according to FIG. 2A from above.

[0063] FIG. 2C illustrates a partly sectional side view of the screw according to FIG. 2A.

[0064] FIG. 2D illustrates the detail A of FIG. 2C.

[0065] FIG. 3A illustrates a perspective view of a third exemplary embodiment of the new screw having a double contour engagement.

[0066] FIG. 3B illustrates a view of the head of the screw according to FIG. 3A from above.

[0067] FIG. 3C illustrates a partly sectional side view of the screw according to FIG. 3A.

[0068] FIG. 3D illustrates the detail A of FIG. 3C.

[0069] FIG. 4A illustrates a perspective view of a fourth exemplary embodiment of the new screw having a double contour engagement.

[0070] FIG. 4B illustrates a view of the head of the screw according to FIG. 4A from above.

[0071] FIG. 4C illustrates a partly sectional side view of the screw according to FIG. 4A.

[0072] FIG. 4D illustrates the detail A of FIG. 4C.

[0073] FIG. 5A illustrates a perspective view of a fifth exemplary embodiment of the new screw having a double contour engagement.

[0074] FIG. 5B illustrates a view of the head of the screw according to FIG. 5A from above.

[0075] FIG. 5C illustrates a partly sectional side view of the screw according to FIG. 5A.

[0076] FIG. 5D illustrates the detail A of FIG. 5C.

[0077] FIG. 6 illustrates a partly broken open and sectional view of an exemplary embodiment of a new deforming tool for producing a screw having a double contour engagement in a position at the beginning of the deforming process.

[0078] FIG. 7 illustrates the deforming tool according to FIG. 6 in a position at the end of the deforming process.

[0079] FIG. 8 illustrates different deforming stages of the screw during its manufacture.

[0080] FIG. 9 illustrates a perspective view of an exemplary embodiment of a new actuation tool for actuating the screw having a double contour engagement.

[0081] FIG. 10 illustrates a sectional view of the actuation tool according to FIG. 9 in a first position at the beginning of contact with the head of the screw.

[0082] FIG. 11 illustrates a sectional view of the actuation tool according to FIG. 9 in a second position during complete contact to the head of the screw.

[0083] FIG. 12 illustrates a perspective view of the actuation tool according to FIG. 9 being cut open in the longitudinal direction.

DETAILED DESCRIPTION

[0084] FIGS. 1A-1D illustrate different views of a first exemplary embodiment of a new high-strength screw 1. The screw 1 is a high-strength screw 1 having a tensile strength of at least 800 N/mm.sup.2, especially an ultra-high-strength screw 1 having a tensile strength of at least 1400 N/mm.sup.2. The screw 1 includes a bainite structure that has especially been produced by austempering and that extends substantially over the entire cross-section of the screw 1. The same applies to the other embodiments of the screw 1.

[0085] The screw 1 includes a head 2, a collar 3 and a shank 4. A threadless shank portion 5 and a threaded portion 6 including an external thread are located at the shank 4. The threadless shank portion 5 could also be omitted. For improving visibility of the details of the head 2 of the screw 1, the shank 4 is partly cut away. Consequently, its entire length is not illustrated. It is to be understood that the shank 4 may have any length and any diameter. The same applies to the other embodiments of the screw 1.

[0086] The head 2 of the screw 1 includes an tool engagement external contour 7 and a tool engagement internal contour 8. In the illustrated example, the tool engagement external contour 7 is designed as an external six-edge and the tool engagement internal contour 8 is designed as an internal six-edge. The tool engagement external contour 7 includes a pluralityin this case sixforce engagement surfaces 9 being designed as approximately plane surfaces and each being interconnected by corners 10. The tool engagement internal contour 8 also includes a pluralityin this case sixforce engagement surfaces 11 being interconnected by corners 12.

[0087] The tool engagement internal contour 8 has a special design including of an arrangement of pocket-shaped impressions 13. The pocket-shaped impressions 13 are designed as cold-formed dents located in the respective force engagement surface 11 of the tool engagement internal contour 8. They are arranged approximately centrally between the corners 12 of the tool engagement internal contour 8. They are located next to the axial end of the head 2 facing away from the shank 4. Their width increases in the direction of the axial end of the head 2 facing away from the shank 4. The pocket-shaped impressions 13 do not extend over the entire width of the respective force engagement surface 11 of the tool engagement internal contour 8. The portions of the force engagement surface 11 of the tool engagement internal contour 8 in which no pocket-shaped impressions are arranged serve to transmit torque by the actuation tool for turning the screw 1. The pocket-shaped impressions 13 are arranged approximately centrally between the corners 10 of the tool application external contour 7 in a circumferential direction.

[0088] The pocket-shaped impressions 13 serve to dislocate material from this inner region and to let it flow into the outer portions of the corners 10 of the tool engagement external contour 7 during manufacture of the screw 1 by deforming, especially cold-forming. It is desired to fill the corners 10 as much as possible such that the upper portions of the corners 10i.e. in the axial end of the head 2 facing away from the shank 4the unfilled corner portions 14 are as small as possible. In this way, it is ensured that the desired torque can be transmitted by the tool engagement external contour 7 as well as the tool engagement internal contour 8. These transmissions may occur alternatively or simultaneously.

[0089] The pocket-shaped impressions 13 are to be differentiated from the central impression 15 serving to provide the material for the entire tool engagement internal contour 8.

[0090] FIGS. 2A-2D illustrate respective views of a second exemplary embodiment of the new screw 1. With respect to the coinciding features, it is referred to the above statements.

[0091] In contrast thereto, the tool engagement external contour 7 is designed as an external twelve-edge. In this case, the pocket-shaped impressions 13 are not arranged axially between the corners 10 of the tool engagement external contour 7. Instead, they are arranged radially inward with respect to each other corner 10 of the tool engagement external contour 7.

[0092] FIGS. 3A-3D illustrate respective views of a third exemplary embodiment of the new screw 1. With respect to the coinciding features, it is referred to the above statements.

[0093] In contrast thereto, the tool engagement external contour 7 is designed as an external twelve-tooth. The tool engagement internal contour 8 is designed as an internal four-tooth. The pocket-shaped impressions 13 are each arranged approximately centrally between the corners 12 of the tool engagement internal contour 8. They are arranged radially inward with respect to one corner 10 of the tool engagement external contour 7. In this case, this is every fourth corner 10.

[0094] FIGS. 4A-4D illustrate respective views of a fourth exemplary embodiment of the new screw 1. With respect to the coinciding features, it is referred to the above statements.

[0095] The tool engagement external contour 7 is once again designed as an external twelve-tooth. The tool engagement internal contour 8 is designed as an internal six-edge. The pocket-shaped impressions 13 are located approximately centrally between the corners 12 of the tool engagement internal contour 8. They are arranged radially inward with respect to every other corner 10 of the tool engagement external contour 7.

[0096] FIGS. 5A-5D illustrate respective views of a fifth exemplary embodiment of the new screw 1. With respect to the coinciding features, it is referred to the above statements.

[0097] In contrast thereto, the tool engagement external contour 7 is designed as an external six-round. The tool engagement internal contour 8 is designed as an internal six-round. The force engagement surfaces 9, 11 are thus not substantially plane, but instead rounded or curved. The corners 10, 12 are not substantially straight, but instead rounded. The pocket-shaped impressions 13 are arranged approximately centrally between the rounded corners 12 of the tool engagement internal contour 8 in a circumferential direction. They are also arranged approximately centrally between the corners 10 of the tool engagement external contour 7.

[0098] FIGS. 6 and 7 illustrate an exemplary embodiment of a new deforming tool 16 for producing a new screw 1 by deforming, especially cold-forming. The deforming tool 16 is part of a multi-stage press. Since the general structure and functionality of a multi-stage press are known to the skilled person, further statements in this regards are omitted.

[0099] The deforming tool 16 includes a stamp tool 17 and a matrix tool 18. The stamp tool 17 includes a stamp 19 being designed to produce the desired shape of the head 2 of the screw 1. The stamp 19 is designed such that it produces the central impression 15 and the tool engagement internal contour 8 with the pocket-shaped impressions 13. The stamp tool 17 is designed such that the tool engagement external contour 7 is simultaneously produced. This progressive process is well comprehensible from a comparison of FIGS. 6 and 7.

[0100] FIG. 8 illustrates different intermediate stages during the deforming process of a blank 20 being designed as a wire section to a screw 1 including a fully completed head 2.

[0101] FIGS. 9-12 illustrate different views of an exemplary embodiment of a new actuation tool 21 for turning (rotating) the new screw 1. The actuation tool 21 is mounted in a screwing tool. The screwing tool may be motor-driven or hand-driven.

[0102] The actuation tool 21 includes a housing 25 in which an external actuation element 22 for engaging the tool engagement external contour 7 of the screw 1 and an internal actuation element 23 for simultaneously engaging the tool engagement internal contour 8 of the screw 1 are arranged.

[0103] The internal actuation element 23 is supported in the housing 25 by a spring 24 to be movable in a translatory direction. The starting position of the spring 24 is illustrated in FIG. 13. The internal actuation element 23 protrudes from the housing 25 in an axial direction. In this way, it serves as an insertion and centering aid when initiating contact between the actuation tool 21 and the head 2 of the screw 1. The internal actuation element 23 is pressed against the force of the spring 24 by the user of the actuation tool 21 resulting in the external actuation element 22 now progressively getting in contact to the tool engagement external contour 7 of the screw 1.

[0104] For example, this functionality of the actuation tool 21 may be used in a sense that a contact is closed and an electrical signal is transmitted only after the end position illustrated in FIG. 14 has been reached. The electric signal leads to the motor of the screwing tool being turned on. In this way, actuation of the actuation tool 21 causing the head 2 of the screw 1 to be damaged is prevented before complete contact between the external actuation element 22 and the tool engagement external contour 7 as well as between the internal actuation element 23 and the tool engagement internal contour 8 has been established.

[0105] Many variations and modifications may be made to the preferred embodiments of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of the present invention, as defined by the following claims.