Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Washer structure – Including means for retaining washer to fastener
Reexamination Certificate
2000-05-03
2001-05-22
Wilson, Neill (Department: 3627)
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Washer structure
Including means for retaining washer to fastener
C411S480000, C411S531000, C411S908000
Reexamination Certificate
active
06234736
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fastening element for securing plate-shaped insulation materials and including a large-surface, flat clamping member, a hollow stem projecting from the clamping member and enclosing a hollow space that opens into an opening formed in the clamping member, and at least one plate-shaped cover for closing the opening and attached to the clamping member.
2. Description of the Prior Art
Insulation materials, in particular, insulation boards are used for heat insulation and partially also for noise insulation of walls and ceilings. Conventionally, the insulation boards are secured to a raw masonry. For securing the plate-shaped insulation materials, fastening elements, which have a large-surface, flat clamping plate from which a stem projects, are used. The stem extends into the insulation board. The fastening element is secured to the masonry primarily with a dowel-like or nail-like anchoring member that forms an extension of the stem. The dowel-like anchoring member is inserted in a pre-drilled bore formed in the masonry and in anchored in the masonry bore by being expanded. A nail-like anchoring member is directly driven into the masonry, without preliminarily forming a bore in the masonry. A bore formed in the stem and opening into the clamping member insures access for an expansion screw or a similar expansion member used for expanding the dowel-like member or to a nail-like member. After the masonry is covered with the insulation material plaster is applied.
The dowel-like anchoring member can, e.g., be formed integrally with the hollow stem. However, primarily, dowel sleeves are used which are inserted through the hollow stems and project therefrom.
It is important that the plaster material does not penetrate into the inner space of the hollow shaft as this can result in formation of a cavity in the surface of the applied plaster layer. If the plaster material and, thereby, moisture penetrates in the interior of the hollow stem, the moisture can cause corrosion of the anchoring member. In addition, there is a danger of formation of thermal bridges which adversely affect functioning of the insulation.
The prior art discloses proposals to close the opening in the clamping member that would permit to prevent the penetration of the plaster and moisture into the interior of the hollow stem. E.g., U.S. Pat. No. 5,118,235 suggests to close the opening with a cover which is connected to the clamping member for a pivotal movement about an axle arranged in the region of the opening. In the closed position, the pivotal cover cooperates with a projection extending from an inner wall of the hollow stem. With this cover, there is a danger that during closing or during application of the plaster, the cover would be inserted so deep that the opening would not be corrected closed. On the other hand, if the cover is not adequately inserted into the opening, the cover would protrude. As a result, the opening again would not be adequately closed. During plastering, the cover can be open even more in the later case. With an inadequate closing of the opening, the plaster material and moisture can penetrate into the inner space of the hollow shaft. In addition, the cover itself is an obstacle to the application of plaster when it protrudes from the opening. This can bring undesirable results. In the open position, the pivotal cover can occupy a random position. On many occasion, the cover partially covers the opening. This presents an obstacle to driving-in of the anchoring member and forces a worker to keep the cover away with one hand while placing the anchoring member into the hollow stem with the other hand.
Accordingly, an object of the present invention to eliminates the drawbacks of the prior art cover.
Another object of the present invention is to provided a fastening element for securing plate-shaped insulation elements which would insure a reliable closing of the opening.
A further object of the present invention is to provide a fastening element the cover of which, in an open position, would not hinder access to the interior of the hollow stem.
A still further object of the present invention is to provide a fastening element that can be simply and cost-effectively produced.
SUMMARY OF THE INVENTION
These and other objects of the present invention, which will become apparent hereinafter, are achieved by providing a fastening element for securing plate-shaped insulation materials or boards and including a large-surface clamping member and a hollow stem projecting from the clamping member. The hollow stem encloses a hollow space that opens into an opening formed in the clamping member and closed by at least one plate-shaped cover attached to the clamping member. The closing cover includes a substantially linear flexor provided in an immediate vicinity of the opening formed in the clamping member. The flexor is bent in such a way that it extends in a plane inclined to a plane defined by the clamping member and to a plane extending parallel to an axis of the hollow stem.
The closing cover according to the present invention insures a reliable closing of the opening in the clamping member of the inventive fastening element. The spatially bent linear flexor insures that the closing has two defined end positions in which the cover is free from tension and compression strains. Only during the transition from an open condition to a closed condition, tension and compression strains appear in the closing cover. The strains reach their maximum magnitude exactly when the closing cover occupies an intermediate position that corresponds to a plane n which the flexor extends. This intermediate position is unstable, and the closing cover automatically seeks to achieve an energetically favorable end position, either the open position or the closed position. The advantage of the closing cover occupying an end position consists in that during mounting of the fastening element, the closing cover does not occupy any undefined position which could interfere with the mounting process. In the folded end position, the closing cover does not change this energetically favorable position and insures a reliable closing of the opening, preventing an accidental penetration of the plaster material or moisture. The fastening element according to the present invention does not need to meet any particular manufacturing requirements as is the case of manufacture of the fastening elements of the state of art. Therefore, the fastening element can be produced by a conventional cost-effective mass-production process, e.g., by plastic infection-molding.
By selecting the inclination angle of the plane, in which the flexor extends, to the plane of the clamping plate or member, the resistance of the closing cover to a change in its open or closed position can be manipulated. The inclination angle also defines the relative position of the closing cover. Preferably, the inclination angle toward the plane, which extends parallel to the axis of the hollow stem, is equal to from about 30° to about 75°. Preferably, an inclination angle of 45° is selected. At this angle, symmetrical force relationships are obtained to a most possible extent, and the closing cover extends in its open position, substantially perpendicular to the surface of the clamping plate
According to a preferred embodiment of the present invention, the clamping member has a depression surrounding the opening for receiving the plate-shaped closing cover. In this way, in its closed position, the closing cover is located in the depression and does not project or projects only to a negligible extend over the surface of the clamping member. The depression forms, at least at a side of the opening opposite the flexor, a stop shoulder which provides support for the closing cover in its closed position. Also, the stop shoulder prevents the closing cover, during closing of the opening, from extending into the interior of the hollow space in the stem. In accordance with a preferred embodiment of
Brown & Wood LLP
Hilti Aktiengesellschaft
Wilson Neill
LandOfFree
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