Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Headed fastener element with nut – washer – securing means or cap – Metallic resilient securing means
Reexamination Certificate
2002-02-05
2004-02-03
Saether, Flemming (Department: 3679)
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Headed fastener element with nut, washer, securing means or cap
Metallic resilient securing means
C411S999000
Reexamination Certificate
active
06685409
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of German Patent Application No. 101 06 093.9-12 entitled “Verbindungselement rnit einer Schraube und einem daran unverlierbar angeordneten Sütutzelement”, filed on Feb. 8, 2001.
FIELD OF THE INVENTION
The present invention generally relates to a screw connector including a screw and a work supporting element being captively connected to the screw. More particularly, the present invention relates to a special design of the thread runout of the screw facing the head of the screw.
BACKGROUND OF THE INVENTION
Screw connectors including a screw and a work supporting element being captively connected to the screw to prevent unintentional detachment of the two elements are produced in series to attain a great pre-production level, and to simplify assembly of the screw connectors. The screw connectors serve to connect components.
A screw connector is known from German Patent Application No. 199 24 502 A1. The known screw connector that functions as a connecting element includes a screw having a head with a head Supporting surface and a shank and a support sleeve that surrounds the shank of the screw and functions as a supporting element. The shank includes a cylindrical shank portion and a threaded portion. The shank portion faces towards the head of the screw, while the threaded portion is more or less located at the free end of the shank of the screw facing away from the head. The threaded portion may also be arranged in a middle region of the shank, for example in the case of the screw at its free end including a centering element.
The support sleeve functions as a supporting element and may be designed as a bush or as a plain washer. The supporting element may also include more of such supporting elements. The supporting element includes a narrowing location having a diameter which is less than the outer diameter of the thread of the threaded portion of the screw. The narrowing location may be produced in different ways, for example by impressions being located on the circumference of the bush, or by a continuous protrusion protruding towards the inside. It is also possible to use separate elements, for example a securing ring, being located in the inner diameter of the bush. When a plain washer is used as the supporting element, the bore of the plain washer forms the narrowing location. In this way, the bore forms a continuous enlarging element protruding towards the inside.
The shank portion of the screw has a comparatively reduced diameter—meaning a diameter which is less than the outer diameter of the thread being located on the threaded portion. The reduced diameter of the shank portion may correspond to the rolling diameter of the screw during its manufacture.
When a thread is to be produced on the shank of a screw—especially by rolling—this is only possible by producing a thread runout facing the head of the screw. The diameter of the thread convolution (or of the thread convolutions) increases in the region of the thread runout facing the head of the screw from the rolling diameter, for example, to the outer diameter of the thread in the threaded portion being located adjacent to the runout. Standardization of the thread runout differentiates between a “standard case” and a so called “short design”. In the standard case, the thread convolution extends about 2.5 rotations of the screw—meaning about 900°—while changing its outer diameter. The short design of the thread runout relates to 1.25 rotations—meaning 450°. Even shorter thread runouts would be theoretically possible, but their production is expensive due to comparatively reduced usable times of the tools for rolling these threads.
In the prior art, in the region of each thread runout—no matter whether in the standard case or in the short design case—there is a conical surrounding cone at the screw, the surrounding cone contacting the narrowing location of the supporting element. When one imagines winding down the thread convolution of the thread runout, one attains a very long inclined plane with a slowly increasing angle of inclination. The surrounding cone and the inclined plane, respectively, have the effect of the danger of the supporting element getting clamped in the region of the thread runout.
Such known connecting elements are especially used as bulk goods at assembly stations. Usually, a feeding apparatus and a conveying apparatus, respectively, are prearranged to the assembly station, the feeding apparatus ensuring that the connecting elements are located in a row, for example. Such conveying apparatuses often use vibration drives. Using vibration drives, there is the danger of the supporting element being vibrated in a way that it is located on the screw too fixedly such that it can no longer be assembled in the assembly station. Even in case such known connecting elements are separately fed to reach their desired place of application, there also is the danger of—at least in some of the connecting elements—the supporting element in the region of the thread runout having a clamped seat at the screw during transportation of the known connecting elements as bulk goods. These disadvantages do not only occur when the narrowing locations are designed as impressions being located at the supporting element in a spaced apart manner, but also when the narrowing locations are designed to be continuous over the circumference of the supporting element. In case of using local impressions, there is the danger of these impressions being vibrated and clamped in the position in which they engage two adjacent portions of the thread convolution in the region of the thread runout facing the head of the screw.
SUMMARY OF THE INVENTION
The present invention relates to a screw connector that functions as a connecting element, including a screw including a head and a shank and a supporting element that surrounds the shank of the screw and functions as a work supporting element.
The shank of the screw has an end remote from the head, and the shank includes a shank portion adjacent the head, a threaded portion more or less remote from the head and an increasing element formed as an inclined step that functions as a stop between the shank portion and the threaded portion. It is to be understood that the thread of a screw always has two ends or runouts, one of them facing the free end of the screw, and the other one facing the head of the screw. The present invention relates to the design of the end of the thread facing the head of the screw.
The threaded portion of the screw has an outer diameter, and it includes a thread runout facing the head of the screw and extending from the thread to the shank portion of the screw. The thread runout has an axial extension and a circumference. The shank portion has a diameter which is less than the outer diameter of the threaded portion. The step is produced by removing at least a portion of the thread runout at least over a part of the axial extension and of the circumference of the thread runout in a way that the step has a an outer diameter which approximately corresponds to the outer diameter of the threaded portion.
The screw connector also includes a work supporting element that is captively connected to the screw and includes a narrowing location facing the shank of the screw having a diameter which is less than the outer diameter of the threaded portion of the screw.
The present invention also relates to a connecting unit including a screw including a head and a shank. The shank has an end, and it includes a shank portion, a threaded portion and a stop element. The threaded portion has an outer diameter, and it includes a thread end facing the head. The thread end has an axial extension and a circumference. The shank portion has a diameter which is less than the outer diameter of the threaded portion. The stop element is produced by removing the thread runout at least over a part of the axial extension and of the circumference of the thread runout in a way that the stop element is formed with has a an outer di
Braun Mario
Sommer Wolfgang
Kamax-Werke Rudolf Kellerman GmbH & Co. KG
Saether Flemming
Thomas Kayden Horstemeyer & Risley
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