DE29816336U1 - Holding and clamping device - Google Patents

Description

Holding and clamping device

The invention relates to a holding and clamping device for pot-shaped or tubular bodies, preferably for ceramic tubes with a circumferential external annular groove for the purpose of fixing these tubes in an adapter unit, for example for connecting a thermocouple protection tube or riser pipe. Components made of ceramic materials are generally brittle and susceptible to breakage. They can usually only be processed with great effort so that they can be adapted directly to components made of other materials without any problems. Therefore, the ceramic components are generally very simple in terms of geometry and, apart from a groove, are smooth and thread-free.

For the assembly and practical use of the ceramic tubes, for example as part of a temperature measuring and/or temperature control device, metal holding and clamping devices in the form of a screw connection with segment rings have been used, whereby the segment rings engage in the groove of the ceramic tubes. The segment rings are in turn clamped between two screw connection parts.

In the case of bending loads or mechanical impacts on the ceramic pipes, the groove area is directly loaded in the rigid connections that have been predominantly used to date, i.e. the forces acting on it act on the weak point of the ceramic pipes, namely where the narrowest cross-section and the largest notch effect numbers are present (groove ends).

The object of the invention is to create a suitable holding and clamping device for ceramic pipes, such that the loading forces no longer act on the weak point of the pipes in the groove area, but are absorbed by a sufficiently large circumferential surface away from the groove.

It is proposed to extend the screw body so that a clamping zone is present which is located in front of the working zone and which can absorb forces, moments or impacts in such a way that no or only a slight force is introduced into the working zone.

According to the invention, a multi-part clamping device is provided to solve the problem, which has a sufficiently large and preferably fully encircling clamping surface on the pipe-side end of the screw connection, wherein the generally metallic clamping part is preferably shrunk onto this clamping surface, for example by mounting the clamping device in a heated state, so that when the pipe and screw connection are at the same temperature, shrinkage forces act, the level of which depends on the previously selected assembly temperature, the realized tolerances and the size of the clamping surface.

Alternatively, a clamping device according to the invention is provided which generates sufficient clamping forces via wedge or conical surfaces which are located on the screw bodies and/or on the components engaging in the groove.

A further embodiment according to the invention provides a separate clamping unit in the area of the clamping zone, which transfers sufficient clamping forces to the pipe outside the groove area.

The clamping methods of thermal shrinking and mechanical clamping are combined in a further embodiment of the invention, such that the mechanically generated clamping forces are increased after the temperature differences between the joined components have been equalized. The total clamping force is then the sum of the shrinking force and the mechanically generated force.

The holding and clamping devices according to the invention result in a shortening of the lever arm acting due to the force absorption in the area of the full cross-section of the ceramic tubes remote from the groove, an increase in the effective clamping surface (the circumferential line is larger at the full cross-section compared to the groove cross-section) and, due to the implementation of fully encircling clamping methods, a very uniform clamping without undesirable stress peaks.

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The holding and clamping device according to the invention is explained below with reference to the figures.

Fig. 1 shows a clamping device for high-temperature pipes (1), consisting of the two screw bodies (2) and (3) as well as at least two segment rings (4) or a groove spring (4). The screw body (3) has a connection option on the side facing away from the pipe, e.g. an external thread for connecting a cable duct. The segment rings (4) engage in the groove (6) of the geometrically simple high-temperature pipes (1). In the area of the clamping zone (5) there is a force-fit connection between the screw body (2) and the pipe (1). The clamping forces are shrinkage forces, which can be generated by preferably heating the screw body (2) and then pushing it over the relatively cold pipe (thermally generated sliding fit) and screwing it to the associated screw body (3). The level of the clamping forces achieved is influenced by the temperature difference, the manufactured tolerances and the size of the clamping zone. If a transverse force acts on the pipe (1), this is absorbed by the clamping zone (5) of the pipe (1) and not by the endangered groove zone (6), as is the case with designs that do not have a clamping zone (5) or do not have a sufficiently large clamping zone (5). This means that the device according to the invention is able to absorb higher disruptive forces (vibration, impact or lateral forces) and will break or suffer other damage much less frequently under given loads.

Fig. 2 shows a variant of the holding and clamping device, in which a wedge clamp is used, in that the segment parts (4) have wedge- or cone-shaped surfaces, so that when the screw bodies (2) and (3) are assembled or joined together, radial clamping forces are created, which press the inner surfaces of the clamping parts (4) in the area of the clamping zone (5) firmly against the contact surface of the high-temperature pipes. Here too, any forces, moments or impacts acting on the lower part of the pipe (1) are completely absorbed by the clamping zone (5) and not passed on to the working zone (6), which would lead to stress peaks and a high risk of breakage due to the very high notch effect numbers there and the smaller pipe cross-section.

By heating the screw body (2) prior to assembly, the clamping forces effective after assembly can be further increased.

Fig. 3 shows a further device according to the invention with additional one- or multi-part clamping units (7) which are suitable for producing clamping forces in the clamping zone (5). The clamping forces preferably act rotationally symmetrically or are fully encircling, i.e. they act on the entire circumference of the pipe (1). For example, the clamping unit (7) consists of a slotted ring (collet) and several screws which press the ring firmly against the clamping zone (5) of the pipe (1).

Claims (11)

Protection claims 1. Holding and clamping device for cylindrical, tubular or pot-shaped bodies (1) with one or more cross-sectional changes (6) such as groove, pocket, cutout, flattening or bore and a clamping zone (5), consisting of at least two screw bodies (2) and (3) and one or more components (4) engaging in the cross-sectional change, which position the body (1) positively in the device with respect to its axial position, characterized, that the body (1) is connected in a force-locking manner to the counter surface of the holding and clamping device in a contact zone (5) adjacent to the cross-sectional change (6) or located at a distance from it, such that the forces, moments and/or impacts acting on the body (1) are directly absorbed by the preferably large clamping zone (5) and do not continue to act as far as the area (6) with notch effects and reduced cross-sectional area, which is very unfavorable in terms of the risk of breakage. 2. Holding and clamping device according to claim 1,
characterized, that the screw part (2) has direct contact with the body (1) and the clamping force is a shrinkage force, such that the screw part (2) is preferably pushed over the body (1) in the heated state using the thermally generated sliding fit and wherein in the cooled state shrinkage forces emanating from the screw body act directly on the body (1), preferably rotationally symmetrically and over the entire length of the clamping or contact zone (5). 3. Holding and clamping device according to claim 1,
characterized, that the screw part (2) in the area of the contact zone (5) has indirect contact with the body (1) and the clamping force is a wedge force, such that the screw part (2) when screwing with the screw part (3) exerts pressure forces (generally axial and radial forces) on the component (4) extending into the clamping zone (5), which in turn exerts clamping forces on the body (1), preferably rotationally symmetrical and acting over the entire length of the contact zone (5), such that the introduction of force into the engagement or groove area (6) is effectively prevented. -3- 4. Holding and clamping device according to one or more of claims 1-3, characterized, that the screw part (2) in the area of the contact zone (5) has indirect contact with the body (1) and the clamping force is generated by a single or multi-part separate clamping unit (7), such that the body (1) in the clamping area (5) has force-fitting contact with the clamping unit (7), which in turn is supported force-fittingly, for example, on an inner surface on the screw body (2), such that in the clamping area (5) between the body (1) and the clamping unit (7) there is a gap-free transition, which prevents force from being introduced into the engagement or groove area (6). 5. Holding and clamping device according to one or more of claims 1-4, characterized, that the shaft-hub tolerance of the body (1) to the screw body (2) or to the clamping unit (7) corresponds to a press fit after assembly. 6. Holding and clamping device according to one or more of claims 1-5, characterized, that the clamping force in the clamping zone (5) is generated by an adhesive and/or sealant or by a hardening substance and/or by a fluid or coating or other gap filling that solidifies in any way and/or generates pressure forces and is preferably an isostatically acting pressure force. 7. Holding and clamping device according to one or more of claims 1-6, characterized, that there is a material connection in the clamping zone (5) between the body (1) and the screw body (2). -5- 8. Holding and clamping device according to one or more of claims 1-9, characterized, that the screw body (2) and/or the screw body (3) has any options for fastening, clamping, screwing (drill holes, threaded holes), clamps (screw body with collar, shoulder or other protruding parts) or rivets in order to connect the device to other metal parts, devices or system parts or containers in a detachable or non-detachable manner. 9. Holding and clamping device according to one or more of claims 1-8, characterized, that the screw body (1) and/or the screw body (2) has a flange shape on the outside and has holes on a suitable pitch circle. - he- 10. Holding and clamping device according to one or more of claims 1-9, characterized, that the screw body (2) and/or the screw body (3) is connected in the external area to a coupling part and/or a flexible structural component (expansion compensator, metal bellows, compensator, sliding tube, joint or spring element), such that the screw unit (2), (3) is movably mounted and/or spring-loaded and the force acting on the body to be protected (1) is thereby additionally reduced. 11. Holding and clamping device according to one or more of claims 1-10, characterized, that the body (1) has protruding parts, preferably beads, ring shoulders, collar rings or noses, which engage in corresponding recesses, grooves or bores in the screw body (2), so that a positive connection between the body (1) and the screw body (2) is present, but compared to claim 1 with a reversal of the engagement in the form of protruding parts in the body (1) and recessed cavities in the screw body (2).