DE8701398U1 - Device for bridging expansion joints in bridges or similar. - Google Patents

Description

Kober AG Bankstrasse 7 CH-8750 Giargs

Device for pressing Qffhniinnsfiigpn in Bridges or similar

The invention relates to a device according to the generic term of claim 1.

Such a device is described in the German patent specification 33 33 880. The elastomer blocks used there to control the spacing between the slats are subjected to shear stress only. This type of elastomer deformation allows for sufficiently large expansion paths; however, only relatively small control forces are developed from pure shear deformation of the elastomer blocks. In order to achieve sufficiently large control forces, the generic device must therefore be provided with a large number of control chains made of such elastomer blocks.

In contrast, the present invention is based on the object of improving the known device in such a way that it develops greater control forces so that the number of control chains can be reduced, while retaining the known simple construction of a control device made of elastomer blocks connected to rigid tabs.

The solution according to the invention is based on the consideration that the elastomer blocks, which have so far only been deformed by shear, can develop greater control forces through additional deformation and that the simplicity of the construction can be maintained by also generating the additional deformation by changing the lamella spacing.

This consideration has led to the solution according to the characterizing part of claim 1. According to the subclaims, such connecting elements can be either cables or tension rods, the latter being attached in an articulated or pivotable manner on the one hand to the associated lamella and on the other hand to the associated tab - either directly or via head plates connected to the elastomer blocks in a shear-resistant manner.

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As a result of a change in the lamella spacing, based on a lamella spacing at which the elastomer blocks are formed - this initial position corresponds to either the completely closed or the maximally open joint - the connecting links subjected to tension cause an additional compression deformation of the elastomer blocks, such that the height of the elastomer blocks before deformation is reduced to a lower height in the compression-deformed state. Timing chains can alternate in this case, with the connecting links producing an increasing compression deformation either with increasing or decreasing lamella spacing, depending on whether the elastomer blocks are stress-free with a closed or open joint.

A particular advantage of the additional compressive stress, which superimposes the shear deformation, is that an internal stress state is imposed on the elastomer blocks, which results in a particularly favorable loading of the elastomer blocks.

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The tensile stresses that always occur in the area of the fastening points when an elastomer block is subjected to shear deformation are effectively reduced by the superimposed compressive deformation, resulting in an optimized stress state that results in increased strength and service life. At the same time, the control forces are significantly increased, as intended. The horizontal force component of the tensile force from the connecting links that run at an angle to the vertical direction is added to the control force from the shear deformation of the elastomer blocks, the vertical force component of which has an effect as a compressive force in the elastomer blocks.

With regard to expedient embodiments of the invention, reference is made to the subclaims and the associated explanations in the description of the figures. In the following, some embodiments of the invention are explained using the drawing.

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It shows

Fig. 1 a section through the bridging device along a vertical plane,

Fig. 2 is a view of the device according to Fig. 1 from below,

Fig. 3 and 4 a control element of the timing chain without deformation of its elastomer blocks with the joint closed and the control element with shear/compression deformation with the joint open,

Fig* 5 and 6 an elastomer block in the undeformed and in the deformed state,

Fig. 7 a symmetrical half-section through

an elastomer block with head plates for connection to the structure and ropes as connecting links, and

Fig. 8 is a variant of Fig. 7.

Fig. 1 shows a joint bridging device with two edge slats (1, 2) and two slats (3, 4) arranged between them, each in cross section. The edge slats (1, 2) are each firmly clamped into the adjoining joint edges (5, 6), e.g. anchored by anchoring parts (not shown) in the concrete body of the joint edges (5, 6). Each control element connects two adjacent slats to one another. It comprises two elastomer blocks (7) each. These are connected on the one hand to the undersides of the slats via head plates (10), on the other hand to a common rigid tab (8) either directly or also via head plates (10). Two elastomer blocks (7) are therefore attached to each tab (8), which are connected either to adjacent slats (3,4) or to an edge slat (1,2) and a slat (3,4). In the open position of the joint shown in Fig. 1, in which the distance between the slats is maximum, tension rods (9) hinged to the side of the head plates (10) or tabs (8) are positioned at an appropriate angle. This reduces the distance between the head plates (10) and the tabs (8) compared to the state when the joint is closed, so that the flanks of the elastomer blocks, which are drawn straight for the sake of simplicity, deform under pressure, whereby whose qualitative course is similar to that of the left

Control element corresponds to dashed lines (11).

In the open joint position as shown in Fig. 1, the elastomer blocks (7) are maximally deformed, i.e. the control forces acting against the opening direction are at their greatest. Their value is made up of a thrust component and a horizontal force component corresponding to the tensile force in the tension rods (9). The tabs (8) also prevent the elastomer blocks (7) from twisting. The control elements, each comprising two elastomer blocks, are arranged in staggered fashion on the underside of the slats, as shown in Fig. 2, so that a continuous control chain is created between the two joint edges (5, 6). Each elastomer block (7) is assigned two tension rods (9) in an opposite arrangement.

According to Figs. 3 and 4, only two lamellas (3, 4) are selected, which are connected to a control element. The control element corresponds to the design in Figs. 1 and 2. According to Fig. 3, the tension rods (9) run approximately vertically when the joint is closed and the elastomer blocks are essentially stress-free. Their height is h . In contrast, the height of the elastomer blocks when the joint is open is reduced to the value h according to Fig. 4, due to the inclination of the tension rods (9). The tension rods (9)

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thus cause an increase in the control force beyond the mere thrust force, namely by the amount that corresponds to the horizontal force component of the tensile force in the tension rods (9). This means that the control force, i.e. the force that counteracts the opening of the slats (3,4), increases with increasing opening.

Conversely, the elastomer blocks (7) could also be attached to a suitably extended tab (8) with a corresponding vertical position of the tension rods (9) at a mutual distance (not shown) that corresponds to the distance when the joint is open, i.e. in this case the elastomer blocks (7) would be stress-free when the joint is open. In this embodiment, control forces counteracting the narrowing of the joint would be generated, which increase accordingly as the joint narrows. In practice, it may be desirable for control forces counteracting every change in the joint (opening or closing) to be present; in this case, it seems expedient to use the alternative control element shown in the drawing and the one described above to construct corresponding control chains and to install these next to one another in the same bridging device.

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Figures 5 and 6 each show a vertical section of an elastomer block (7) with a central bore (12). A tension rod (13) with joint heads (14) at its opposite ends runs through this bore, with the joint heads (H) being pivotably mounted in a spherical castellated bearing shell (15) of the head plate (10) or the bracket (8). Here too, the tension rod (13) forces the elastomer block (7) to shorten in the vertical direction from the height h to the height h when the slats are deflected as shown in Fig. 6.

Fig. 7 shows the upper half of a symmetrical elastomer block (7), in which the connecting link between the upper and (not shown) lower head plate (10) consists of several, preferably six, star-shaped cables (16), which together form a central tension member. The deflected upper ends (17) of the cables (16) are anchored by means of a screwed-in clamping plate (18). Thanks to the flexibility of the cables (16), a special pivot bearing for the tension member can be dispensed with.

Alternatively, the cables can also be guided in separate off-center holes, e.g. distributed in a circle.

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Fig. 8 shows a solution similar to Fig. 7, but with the difference that the rope ends (17) are cast in the respective head plate (TO). The head plates can be made of cast aluminum or hardening plastic.

The head plates (10) are connected to the elastomer blocks (7) by vulcanization; their connection with lamellae or tabs is not shown in detail in the drawing; for example, a screw connection using ears protruding from the sides of the head plates, which have eyelets, is possible.

The rigid tabs (8) are preferably made of metal or a rigid plastic. A suitable material for the elastomer blocks is rubber or polyurethane.

Claims (10)

1. Device for bridging expansion joints in bridges or the like, which is supported by cross beams on the joint edges and which has at least three slats parallel to one another and to the joint edge, of which the two outer slats (edge slats 1, 2) are attached to the joint edge (5, 6), whereby all slats (1, 2, 3, 4, ) are connected to one another in pairs to form a control chain by means of at least one rigid casing (8) each, which is attached to each slat of a slat pair via a shear-deformable elastomer block (7), characterized, that each elastomer block (7) is assigned a tensile movable connecting element between the lamella and the tab (8) such that when the distance between the lamellas changes, in addition to the shear deformation of the elastomer blocks, their compression deformation also occurs. 2. Device according to claim 1, characterized in that the elastomer blocks (7) are each connected on the lamella side and/or the tab side to a head plate (10) in a shear-resistant manner, to which the associated connecting member is anchored, and that the head plates (10) are firmly connected to the tab (8) or lamella. &igr; ¹¹ · .' J : ¹ Il' ! '**' 3. Device according to claim 1 or 2, characterized in that the connecting member is designed to be movable and/or is articulated to be movable. 4. Device according to claim 1 or 2, characterized in that the connecting member is designed as a rope or as a bundle of such ropes (16). 5. Device according to claim 3, characterized in that the cable or cables (16) run through a central bore in the elastomer block (7). 6. Device according to claim 3, characterized in that several cables run through holes outside the center of the elastomer block. 7. Device according to claim 1 or 2, characterized in that the connecting member comprises one or more tension rods (9, 13). It I S · < 1 «·. I t «ft «» «it · · I t t t 1 ■ ···<· «I 1 &Lgr; «Atf«· · ■ ■· tt 8. Device according to claim 7,
characterized, that the tension rod(s) (9, 13) are aligned approximately vertically in the stress-free state of the associated elastomer block (7). 9* Device according to claim 7,
characterized, that each elastomer block (7) is assigned two tension rods (9) on the outside and opposite each other. 10. Device according to claim 7, ! characterized, ] that each elastomer block (7) is assigned a tension rod (13) running through a central bore (12) of the same, the ends of which are each connected via a joint to the lamella and tab (8) or to the head plates (10).