1. Field of the Invention
The present invention relates to an expansion rivet.
2. Description of the Related Art
One expansion rivet is known from EP 1 375 931 A1. This previously known expansion rivet is provided with a holding element comprising a number of radially outwardly splayable legs and a bearing plate to which the legs are attached. An actuating element comprising a shank and able to be inserted into the holding element through a passthrough recess of the bearing plate is also present. In a locking position of the actuating element, the legs are splayed radially outwardly by the engagement of expansion projections disposed in an active region of the legs. The actuating element is provided with a head plate which abuts the bearing plate in the locking position. Also present are detent lugs, which are attached to the shank and protrude beyond a lateral surface thereof that is configured snugly with the passthrough recess, and which are shallowly beveled away from the head plate via a sliding surface and are set at a steep angle confronting the head plate via a reverse detention surface. Said detent lugs are disposed at a distance from the head plate that is adapted such that when the reverse detention surfaces abut the head plate, the shank is free of engagement with the expansion projections. In this expansion rivet, the actuating element and, correspondingly, the passthrough recess have a roundish cross section, the detent lugs being arranged at a 90 degree angle on the outside of solid, radially extending webs and sliding in recesses assigned to them. Aligning the actuating element for insertion into the holding element is not made very easy by this means, since no direction of execution is specified. There is also a risk that the detent lugs may be sheared off as a result of relative rotation between the holding element and the actuating element.
Another expansion rivet very similar to the aforesaid embodiment is known from WO 03/072957 A2.
Another expansion rivet is known from U.S. Pat. No. 5,201,623. This expansion rivet is provided with a holding element comprising at least two radially outwardly splayable legs and a bearing plate to which the legs are attached. The legs are provided with inwardly directed expansion projections. The previously known device further comprises an actuating element composed of a shank on which a projection arrangement is formed. In an installed position, the expansion projections are disposed in indentations of the projection arrangement, so that the legs extend substantially parallel to the shank and the expansion rivet can be inserted in a seating recess extending for example through a substrate element and a bearing element. In a locking position of the actuating element, after the shank has been moved axially in the direction of insertion, the legs are splayed outwardly due to the engagement of the projection arrangement with the expansion projections in an active region. The expansion rivet can be locked in the seating recess in this way.
To release the expansion rivet, the shank is pushed axially farther in the insertion direction until the expansion projections come to rest in additional indentations of the projection arrangement and the legs again extend substantially parallel to the shank. The expansion rivet can now be removed from the seating recess. For the expansion rivet to be reused, the shank must be moved back to the installed position against the direction of insertion. This has proven to be relatively bothersome, however, and causes not inconsiderable wear, particularly on the expansion projections and the projection arrangement, due to the need to pass through the locking position in two directions for one seating and release cycle.
Known from EP 0 682 186 A1 is an expansion rivet in which a head plate of an actuating element can be inserted in an insertion recess provided in a bearing plate of a holding element.
The present invention provides an expansion rivet, which is distinguished by simple insertion and high resistance to twisting of the actuating element relative to the holding element.
By virtue of the configuration of the present expansion rivet, the actuating element can be inserted with relatively low insertion forces into the holding element, in an easily recognizable orientation with respect thereto, until the detent lugs catch behind the head plate, since the detent lugs can be deformed relatively easily on encountering the plinth pieces during insertion. Due to the cornered form of the cross section of the shank of the actuating element and of the passthrough recess, the detent lugs are well protected against the shear forces they would be subjected to as a result of relative rotation between the holding element and the actuating element.
The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. Although the exemplifications set out herein illustrate embodiments of the invention, in several forms, the embodiments disclosed below are not intended to be exhaustive or to be construed as limiting the scope of the invention to the precise forms disclosed.
Attached to bearing plate 2 on a bearing side 6 disposed opposite the cover side 4 of bearing plate 2 are two legs 7, which are oriented substantially at right angles to bearing plate 2 and are disposed laterally spaced apart from each other, a shank recess 8 thus being formed between the legs 7. In a region adjoining bearing plate 2, the legs 7 comprise circumferentially extending detent rings 9, while the free ends of the legs 7, i.e. the opposite ends from bearing plate 2, are configured with conical portions 10 ascending toward bearing plate 2 from the outer edge of the free ends.
The exemplary embodiment of an inventive expansion rivet according to
Formed on the broad lateral surfaces 14 are projecting plinth pieces 16, which are disposed at a distance from head plate 12 and to which are attached detent lugs 17 that point toward head plate 12 and protrude beyond narrow lateral surfaces 15. The detent lugs 17 are shallowly beveled away from head plate 12 via sliding surfaces 18, and are set at a steep angle confronting head plate 12 via reverse detention surfaces 19. In prolongation of the plinth pieces 16 in the direction of head plate 12, fill-in pieces 20 dimensioned in accordance with plinth pieces 16 and adjoining head plate 12 are attached to the broad lateral surfaces 14.
Attached to narrow lateral surfaces 15, between head plate 12 and each of detent lugs 17, is a locking projection 21 that is shallowly beveled both toward head plate 12 and away from head plate 12 via canted surfaces 22.
In the representation of
The transposition of actuating element 11 from the position shown in
As can be appreciated with particular clarity from
The expansion rivet according to the invention can be removed from the seating recess 26 by placing the flat end of a screwdriver or other similarly shaped tool on bevel 5 and lifting head plate 12 of actuating element 11 out of insertion recess 3, and then grasping it for example between two fingers and exerting a pulling force against the direction of insertion until the locking projections 21 emerge from passthrough recess 23 and the reverse detention surfaces 19 of detent lugs 17 abut the bearing side 6 of bearing plate 2, causing the legs 7, due to their inherent elasticity, to automatically revert to a mutually substantially parallel position. In the now-restored installed position according to
While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
Number | Date | Country | Kind |
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102004036621.7 | Jul 2004 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP05/04934 | 5/6/2005 | WO | 1/26/2007 |