IE60239B1 - Expansion plug - Google Patents

Description

The invention relates to an expansion anchor plug. An expansion plug, which can be used both as aa expansion plug aad' a buckling plug, is described in DS-B-22 54 502 aad ΑΤ-Δ-325 632.

With this known all-purpose plug the shank, which comprises annular ribs® is constructed as a solid sleeve, which is subdivided by longitudinal slits into expansion segments. These expansion segments are pressed * outwards over a substantial part of the shank length, * and. the bore hole walls ia lightweight aaterials or f, soft, porous aasonry often, cannot withstand this expansion pressure over a substantial length of the shank, such that they are destroyed and the retaining function is lost.

The problem on. which the invention is based is therefore that of improving a plug of the above type in such a way that it ensures reliable anchoring while maintaining its expansion function ia solid aasonry such, as concrete ©nd also in lightweight partitios walls, without the bore hoi® walls being pushed ia and caused to collapse.

According to the invention there is provided an expansion and buckling plug of plastics material comprising a solid plug foot with aa axial through-hole for self-cutting of a thread,, a closed plug neck and an expandable plug shank lying between the plug foot and plug neck and forming expansion members, said plug shank comprising a sleeve provided with longitudinal slits aad having supporting rib® formed thereon asd surrounding it externally, characterized ia that the surrounding supporting ribs .are constructed a® & screw helix forming the expansion members# the individual threads of the screw helix being at a distas.ee from each other asd being so connected together by a breakable Jacket/ which is thin-walled in coanarison with the supporting ribs, that between the threads of the screw helix there is formed an outwardly encircling, helical groove with the jacket as base# such that the supporting ribs are held in politics fey the jacket during insertion fata the bore hole® the longitudinal slits being constructed is the jacket .between the threads of the screw helix.

By aeaas of the iaveatioa, fixed anchorage is aheieved both in hollow feuildiag materials fey knotting Chuckling? at the rear asd ia solid walls. Th® plug cas preferably also toe used ia lightweight materials such as f ytos etc. The thia jacket provided according to the invention in the shank part of the plug acts oaly as a carrier for the screw walls, not as aa expansion member, l· however. This thia jacket's only task is ta maintain the shape of the plug during insertion into the bore hole and to keep the threads ©f the screw walls at their predetermined separation® unless linear compression is desired because the plug hole is too short® which coMoressios caa be effected by driving the plug is, since this thin jacket sleeve ensures axial (and radial) spring loading. During screwing or driving in of an expansion body the thin jacket is destroyed, and the helical threads, which alone ars effective as expansion members, can then engage ia the bore hole walls. Setweea 5 the screw threads the bore hole walls remain extensively free from expansion pressure, such that no damage is to 7 be feared. The preferred left-handedness of the screw * 10 helix ensures that during screwing-la of the usual screws provided with right-handed threads the plug shank is axially loaded by the friction which the screw helix exerts on the bore hole walls. >? Δ plug is already known froa FR-A-1 340 396 comprising encircling supporting ribs ia the fora of a screw helix. Vith this known plug the individual threads of the screw helix are directly adjacent each other and it cannot be foreseen at which points during screwing-in of the screw the plug jacket will burst open» since no longitudinal slits are present in the expansion part of the plug to ensure defined and uniform radial expansion.

The solid construction, known per se, of the plug foot ensures that the plug caa be used as a buckling plug. As soon as the screw head is adjacent the part to be secured and is screwed further, the free plug part buckles and forass a knot at the rear of the hollow space. To make this buckling easier, a desired buckling point is provided at the beginning of the foot part in the form of a groove.

The substance of the invention consists therefore ia the fact that the plug shank is substantially formed of the screw helix as an expansion segment and the thinwalled jacket carrying the helix serves merely to maintain the position, i.e. the separation, of the helix, during insertion of the plug into the bore hole.

On screwing-in of an expansion body into the plug this thin jacket is destroyed without hindering the expansion function and thus has so effect oa withdrawal values.

The actual anchorage members are the expanded helices, which ensure reliable transmission to masonry of any type.

An exemplary embodiment of the invention is described below with the aid of the drawings, in which: Fig. 1 is a side view of an expcnsion plug constructed according to the invention? Fig. la is an axial view of the plug according to Fig. 1 viewed from the plug foot end; Fig. lb is an axial view of the plug according to Fig. 1 viewed froa the plug head end: Pig. 2a shows aa axial section of the plug shown in Fig. 1; Fifs· 2 b is a perspective view of the plug according to Fig. 1; Fig. 3 is & diagrammatic representation. of a plug assembly with expansion into solid building material; Fig. 4 is a diagrammatic representation of the plug according to Figs. 1 and 2 assembled Im solid building material with too short a plug hole and linearly compressed plug shank; Fig. 5 is a diagrammatic view of the plug according to Fig. 1 ia push-in assembly and Fig. β is a diagrammatic representation of the plug ia an assembly with hollow building materials with expansion or knotting of the plug shank.

The plug comprises a plug neck 10, a plug foot 12 and aa expandable plug shank 14 located between the plug foot and the plug neck.

The plug neck 10 consists of a closed sleeve 1©» which as the outside comprises ribs Id serving as securing means against rotation and tapering towards the plug shank 14, four of which ribs 18, as aay be seen froa Fig. lb, are arranged at equal angular distances of 90“ froa each other. Betueen the rib® 18, at the upper end of the closed sleeve id, there are farmed radially outwardly projecting flange tabs 20, which fora a cross and which can be displaced upwards during push-in assembly (Fig. 5J>. The plug neck 10 comprises a screw insertion hole SS with a relatively large diameter, such that the shank of a matching scare* can pass through without exerting a® expansion effect.

The plug foot 12 consists of a closed sleeve 24 with as axial hole 26, into which a matching wood, screw caa cut a ©bread. This hole 26 (Fig. la) is crosssect ional ly cross-shaped or polygonal. Tbs plug foot 12 comprises a conically foned insertion end 30, with which it penetrates the bore hole. An encircling annular groove 32* is located in the transition area between plug foot 12 and' plug body 14» and this annular groove 32 acts as a hinge or as the desired buckling point, so f that the segments of the plug body caa expand freely outwards during installation ia hollow blocks or hollow bodies, without tearing open the plug foot. i The plug shank 14. which contains: the essential features of the invention, consists of aa inner thin plug jacket 34 in the for» of aa Interrupted spacer sleeve, which surrounds a cylindrical expansion channel 36» which develops via a conical extension 36 into the » insertion hole 22 and has a diameter which is smaller than the expansion part of the etching expansion screw. 5 This plug jacket 34 has on its outside an integral screw J helix 40,, which - as aay be sees froa Fig. 1 - has the fora of a double-threaded, left-handed thread. As sse,y be seen from Fig. 2a, the cross section of this screw helix 40 is is the fora of a parallelogram, but it can also be rhomboid, trapeziform or ia the form of an irregular square. Between the screw helices and outside the plug jacket 34 there runs e, helical groove 42, which also preferably has a cross section im the form of a parallelogram. On the outside of the screw helix 40 oa the edge facing the plug neck 10 there are formed flat ribs or plates 44 and 45, which fora barbs on the plug shank. These plates each extend over 160° with aa angle of incidence changing with respect to the axis, such that at the transition points, as may be seen ia particular from Fig. 1, th® ribs or plates 40 aad 44 comprise irregularities, the planes of the ribs ar plates at the transition points being approximately perpendicular to each other.

The plug jacket 34 comprises axial slits between the individual threads of the screw helix 40, which ease the deformation of the plug.

The plug acts as aa expansion plug when inserted in a matching plug hole 50 Fig. 3. The screw 56 digs into the plug foot and cuts its thread. Ia thi© way axial compression occurs, whereby th® expansion pressure is increased.

The flange tabs 20 are supported on the facing layer 3 5 53» aad ia this area ao expansion of the plug occurs. In Figs. 3· to 6 a plate 62 is attached to the masonry. Instead of this, aay other object could be attached by th® screw, la Fig. 4 the plug hole '54 has turned out to bs too 40 sfaesTt,, Nevertheless, the plug car. be driven into this plag hoi®, because it caa be axially compressed owing te • the screw helix arrangement in conjunction with the thia plug jacket 34, evea before the screw 56 is screwed ia.

, On screw!ng-in of the screw expansion again occurs ”L 45 within th® solid material.

The plug aceordiag to th® investioa is, as Fig. 5 shows, also suitable for push-in assembly. Ia this case, the plug is inserted through the hale in the plate S2 and the plug hole, and then the screw is driven in by means of a hammer,, the flange tabs 20 being displaced, , such that the plug can be driven in to the desired depuh. i According to Fig. 6., the plug is inserted into hollow material o0; and, as may be seen, the screw has cut its thread into the plug foot and the helices have buckled outwards and become knotted, such that fixed axial fastening to the hollow mat erial is ensured.

In addition to the exemplary embodiment shown, inclined, interrupted ribs running parallel to the slope can also be attached on the outer diameter of the thread helices to the right or left or on both sides, said ribs again resulting in a strengthening of the anchorage. The plug according to ths invention acts thereafter as an expansion, plug or a buckling plug, depending on the material to be used, such that the plug can be used both in solid masonry and in hollow materials such as hollow tiles, plaster board etc.

The division of ths flange into flange tabs projecting radially la the manner of a cross ensures the fulfilment of the function of a cap plug, the flange’ tabs being displaced by ©0° aad disappearing in the bore hole, however, on driving through by aeans of aa expansion body, i.e. by seans of a nail or wood screw (push-in assembly).

Claims (10)

1. CLAUSE

1. Aa expansion and buckling plug of plastics material comprising a solid plug foot with as axial through-hole for self-cutting of a thread, a closed plug neck and am expandable plug shank lying between the plug foot and plug seek aad forming expansion members „ said plug shank comprising a sleeve provided with longitudinal slits and having supporting ribs formed thereon and surrounding it externally, characterized in that the surrounding supporting ribs.are constructed as a screw helis forming the expansion members, the individual threads of th© screw helix being at a distance from each other and being so connected together by a breakable jacket, which is thin-walled in comparison with the supporting ribs, that between the threads of the screw helix there is formed an outwardly encircling, helical groove with the jacket as base, such that the supporting ribs are held ia position by the jacket ..during insertion into the bore hole, the longitudinal slits being constructed in the jacket .between the threads of the screw helix.

2. A plug according to claim 1, characterised in that the screw helix is left-handed.

3. A plug according tea claim 1 or claim 2 S characterized in that the cross section of the screw helix is in the shape of a parallelogram, a trapezium or saw tooth or is triangular.

4. A plug according to claim 1, characterized in that the screw helix comprises a narrow rib projecting outwards.

5. A plug according to claim 4, characterized in that the ribs are attached to the edge facing the plug seek of the cross-sectionally trapazixona screw helix and are constructed to be cross-sectionally outwardly tapered and form a sharp—angled edge.

6. A plug according to claim 4, characterized θ Ιa that the ribs are each arranged to extend over 180 end differently with respect to the plug axis and ia that the planes of the ribs are approximately perpendicular to each other at the transition points.

7. A plug «according to aay one of claims 1 to, © 6 characterized in that the plug shank comprises a multi threaded screw helix.

8. A plug according to any one of characterised in that flange tabs are ths form of a cross on the plug neck f tabs may be outwardly bent. claims 1 to 7 8 provided in which flange

9. A plug according to any one of claims 1 to 8, character!sed in that the plug foot comprises a 10. Cross-sectionally cruciform threadable hole.

10. A plug according to claim 1, substantially as hereinbefore described with particular reference to and as illustrated in the accompanying drawings.