Clampable electric heating device

Abstract

20. The electric heating device as claimed in claim 19, wherein the locking device comprises a locking cam which is secured to the locking cam by a locking camshaft and a locking camshaft configured to lock the locking cam.

Description

Technical Field

[0001] The invention relates to an electric heating device. Background Art

[0002] Heating devices with electric heating elements are known from the prior art, which are pushed onto the object to be heated and fastened thereto by clamping. For example, such heating devices are used as nozzle heaters in injection molding machines or in hot runner and distributor systems to heat the nozzle bodies.

[0003] The prior art available on the market is known to surround a heating element with an integral clamping sheath, which is in direct contact with the heating element or, for example, indirectly when the heating element is embedded between an inner and an outer metal sheath. The clamping sheath has overlapping sections, viewed in the radial direction, with a wedge mechanism, actuated by a screw, arranged between these overlapping sections. If the screw is rotated in one direction, the wedge mechanism moves so that its height changes, which in turn increases the distance between the overlapping sections of the clamping sheath. Since the length of the clamping sheath is essentially constant, this results in the heating device being clamped onto the object to be heated. Rotating the screw in the other direction loosens the clamping sheath again.

[0004] A problem with such heating devices with a clamping jacket is that, due to the wedge-shaped mechanism, the space requirement for the clamping mechanism is increased in the radial direction, since in many cases, especially in hot runner nozzles, the individual nozzles to be heated are arranged in a block and there is only a relatively narrow tubular channel between the nozzles and the block, into which the heating device must fit.

[0005] Especially for applications where this increased space requirement cannot be met, heating devices have been developed, such as those disclosed in DE 20015016 U1 or DE 202011003451 U1. In these heating devices, a heating element is arranged between an inner and an outer metal jacket and has a slot extending axially through it. Furthermore, clamping elements are provided that interact with the outer metal jacket so that their displacement in the axial direction changes the circumferential width of the slot, thereby achieving a clamped position on the object to be heated.

[0006] A major problem with these heating devices is the handling of the clamping elements, which, when the heating device is pushed, must often be performed within a narrow tubular passage that is only accessible from one side. For example, loosening the clamping elements is virtually impossible. A further problem with these heating devices is that their length necessitates the arrangement of multiple clamping devices in axial sequence to ensure sufficiently close contact between the heating device and the object to be heated so that each can be clamped. Summary of the Invention

[0007] It is therefore an object of the present invention to provide a clampable heating device in which improved operability of the clamping element is ensured. This object is achieved by the heating device of the present invention.

[0008] The electric heating device according to the present invention comprises: an axial opening for receiving an object to be heated, the outer contour of which may preferably be cylindrical; an electric heating element preferably surrounding the axial opening at least in sections; and a clamping sheath, preferably in the shape of a cylindrical sheath or a truncated cone sheath, for generating an adjustable force acting radially in the direction of the axis of the axial opening.

[0009] The following explanations should help to provide a clearer understanding of these self-explanatory terms:

[0010] The geometry of such a heating device can be particularly preferably described by means of the geometry of a cylinder or a generalized cylinder and cylindrical coordinates. The direction of the cylinder axis is predetermined by the axis defining the axial opening of the heating device, into which the object to be heated is usually inserted, and is referred to hereinafter as the axial direction.

[0011] A force acts radially in the direction of the axis, and the force acts in the direction of the axis between a point of the cylindrical sheath and a point of the axis on a connecting line perpendicular to the axis, and is therefore particularly suitable for pressing the electric heating device onto an object to be heated arranged in its axial opening.

[0012] The spatial path of the electric heating element can be described in particular in these cylindrical coordinates, that is, by its position on the axis of the axial opening, its distance from the axis of the axial opening in the radial direction, and its polar angle between 0° and 360°. If the different polar angles used to describe the path of the electric heating element are located in the region of the axial opening, the electric heating element surrounds the axial opening at least in sections. This is particularly the case when the side of the electric heating element facing the axial opening lies on an imaginary cylindrical or truncated cone surface that preferably coaxially surrounds the axial opening, and this is particularly the case when the electric heating element extends in a spiral or meandering manner on an imaginary cylindrical or truncated cone sheath, wherein the slope can change in a direction parallel to the cylindrical or truncated cone axis.

[0013] According to the present invention, at least the clamping sheath of the electric heater is penetrated at least in sections by a recess, which can be embodied in particular as a slot. In other words, a recess is also to be understood as an opening or a perforation; groups of openings or perforations are also conceivable. The recess penetrates the clamping sheath at least in sections and therefore does not necessarily extend over its entire length.

[0014] The width of the recess or in particular the width of the slot is understood here to mean the distance between opposite edge points of the recess substantially perpendicular to the axis of the axial opening, which must be variable by means of at least one clamping device.

[0015] An alternative description of the fact that the width of the recess can be varied by means of the clamping device can be made again using the description of the recess in a cylindrical coordinate system: at each point on the cylinder axis where the recess is located, the recess covers a specific polar angle range. The width of the recess can be varied by means of the clamping device if the polar angle range covered by the recess varies at these points on the cylinder axis at different positions of the clamping device.

[0016] It is essential to the invention that at least one component of the clamping device is rotatably supported or rotatably supported relative to the clamping sleeve about a rotation axis perpendicular to the axis of the axial opening, wherein this component interacts directly or indirectly with the clamping sleeve in such a way that a rotation of the rotatably supported or rotatably supported component of the clamping device changes the width of the recess or, in particular, the width of the slot.

[0017] It should be noted in particular that in various embodiments of the electric heating device according to the present invention, the clamping sheath can be realized as a separate additional component on the one hand, or by a different component of the electric heating device itself on the other hand.

[0018] For example, in an electric heating device in which the electric heating unit is embedded in a powder or granules with good thermal conductivity, the clamping sheath can be formed by a tubular outer sheath having a recess or a slot, the electric heating element filling the inner space between a tubular inner sheath having a lead-out portion which can be designed as a slit and a tubular outer sheath having a recess which can be designed as a slot, which is usually arranged concentrically therewith, the tubular outer sheath and the tubular inner sheath being connected to each other at the edge of the recess or slot via lateral boundary surfaces.

[0019] In an embodiment in which the helical electric heating element in the form of a tubular spiral is surrounded by a tubular outer sheath having recesses, preferably in the form of slots, and rests directly on the tubular outer sheath, the outer sheath can also form a clamping sheath.

[0020] And in an embodiment in which the tube spiral is inserted into a groove introduced in a metal surface, wherein the metal surface is the surface of a metal body preferably in the form of an in particular grooved tube, wherein this form can, for example, be machined from solid material, but can also be produced by rolling up a metal sheet before or after insertion of the tube spiral, the metal body can form a clamping sheath.

[0021] Unlike the prior art embodiments in which the linear movement is initiated directly, the design according to the invention requires that the tool engagement only take place at one position, which remains fixed. Since the rotation can be initiated not only with a clamping tool having a straight axis but also with an angled clamping tool, the space required for operating the clamping device is also very small.

[0022] In a first type of clamping device of particularly simple construction, the rotatably mounted or rotatably mountable component of the clamping device is a disk having engagement means, wherein the engagement means interact with complementary engagement means arranged directly or indirectly on the clamping jacket.

[0023] It should be noted that a clamping device of this type can also be designed similarly with a geometry other than a circular disk, such as a rectangle or a square.

[0024] It should be noted here that the difference between this type of engagement means and complementary engagement means lies in the location where they are arranged, not in whether they are projections or receptacles for such projections. The engagement means are always found on the disc; the complementary engagement means are found on the clamping sheath.

[0025] The interaction of the engagement means and the complementary engagement means creates the possibility of exerting a force on the clamping sheath which reduces the width of the recess, in particular the slot, and thus clamps the electric heating device to the object to be heated.

[0026] Thus, in a first alternative, the engagement means may be a projection, which may be, for example, pin-shaped, cuboid or curved, and the complementary engagement means may be a recess, in particular a notch, groove or perforation, whereas in a second alternative, the complementary engagement means are a projection and the engagement means are a recess, in particular a notch, groove or perforation.

[0027] Advantageously, the projection, whether it is the engagement means or the complementary engagement means, is formed by a component fastened to the disc or to the clamping jacket, i.e., is not embodied as an integral connection to the disc or the clamping jacket. This can significantly contribute to a particularly simple assembly of the clamping device.

[0028] This applies in particular if the projection and the depression contact one another at least in sections in the undercut, thereby securing the disk.

[0029] Typically, during the movement of the disk, the projection is guided along the lateral edge of the recess, which at least partially faces the recess. Since the positions of the engagement means arranged on the disk are predetermined and fixed, changes in the distance between the points or areas where the engagement means and the complementary engagement means are currently in contact with each other are converted into changes in the width of the recess in the clamping sheath. The movement of the disk can be particularly smooth when the recess or edge against which the projection abuts or interacts is curved. This is particularly true when the curvature of the recess varies.

[0030] Particular flexibility in the design and simple production of the recesses can be achieved in that these recesses form complementary engagement means arranged on the clamping sheath and extend in a separate part fixed to the clamping sheath, which is therefore not connected integrally to the clamping sheath.

[0031] In order to be able to initiate the rotational movement particularly easily, it is advantageous if the clamping device has a tool receptacle located on the rotation axis of the rotatably mounted part of the clamping device. Such a tool receptacle can be, for example, a slot or a cross-shaped slot for receiving a screwdriver, or a square, hexagonal or star-shaped recess for receiving a square wrench, an Allen key or a star wrench.

[0032] In order to keep the required installation space small, it is advantageous if the clamping sheath has a recess in which the clamping device is arranged at least in sections.

[0033] In a second type of clamping device, it is provided that the complementary engagement means arranged on the clamping sleeve bridges the recess, which can in particular be designed as a slot, has a first end on one side of the recess and a second end on the other side of the recess, the first end being connected to the clamping sleeve and the second end engaging in the disk, or the disk engaging in the second end.

[0034] While in the first type of clamping device discussed above the disc bridges the recess or, if necessary, the recess is specially designed as a slot, this is accomplished in the second type by a complementary engagement device, so that the complementary engagement device in this type is not only formed by a projection or recess at the clamping sleeve, but also, for example, by a strip-like structure bridging the recess, which has a projection or recess at the end interacting with the disc, which engages with an engagement device, for example in the form of a recess or projection, provided on the disc, or indirectly, for example, by arranging a pin at this end, and a connection with the clamping sleeve is established at the opposite end of the structure bridging the recess, which can also be done, for example, by hooking the bent end of the structure bridging the clamping sleeve into the recess of the clamping sleeve.

[0035] In a third type of clamping device for an electric heating device according to the invention, the clamping sleeve has a bearing defining an axis of rotation perpendicular to the axis of the axial opening, so that a part of the clamping device having a toothed structure on its circumference can be rotatably supported in the bearing. The clamping sleeve also has complementary engagement means, which increase in distance from the recess, or, if the recess is so embodied, from the first end of the slot to the second end thereof.

[0036] The clamping device further comprises a clamping slide, wherein the clamping slide bridges:

[0037] - engagement means which engage with said complementary engagement means of said clamping sheath;

[0038] an opening extending parallel to the axis of the axial opening, the opening having at least one edge extending parallel to the axis of the axial opening, the edge having a toothing complementary to the toothing and with the bearing exposed;

[0039] - said recess; and

[0040] The clamping slide is or can be in contact with the clamping sheath on the side of the recess opposite the engagement means.

[0041] As a result of this arrangement, when the part of the clamping device having a tooth structure at its circumference is rotatably supported in the bearing and rotates, the clamping slide is axially displaced by the interaction of the tooth structure with the complementary tooth structure, and the width of the recess is thereby changed at least over a portion of the axial displacement path.

[0042] In particular, with the third type of clamping device, it is possible that the part of the clamping device having a toothed structure on its circumference is not permanently arranged on the electric heating device, but only when a change in the clamping effect is to be effected. In particular, the part of the clamping device having a toothed structure on its circumference can be formed by a tool which, in the simplest case, is merely a star wrench. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention will now be described in more detail with reference to the accompanying drawings showing embodiments thereof. In the accompanying drawings:

[0044] Figure 1a shows an exploded view of a first electric heating device having a clamping device according to a first type;

[0045] Figure 1b Shown Figure 1a The appearance of the assembled electric heating device;

[0046] Figure 1c Shown Figure 1b A cross-sectional view of a detail of the clamping device;

[0047] Figure 1d Shown Figure 1a An enlarged view of components of a clamping device of an electric heating device;

[0048] Figure 1e Components of a first variant of a clamping device of the first type are shown;

[0049] Figure 2 A diagrammatic illustration of the mode of action of a first type of clamping device based on a second variant of such a clamping device is shown;

[0050] Figure 3a A possibility for mounting a clamping device of the first type based on a third variant of such a clamping device is shown;

[0051] Figure 3b Shown Figure 3a Cross-section of the installed clamping device;

[0052] Figure 4a shows the appearance of a second embodiment of an electric heating device having a fourth variation of the first type of clamping device;

[0053] Figure 4b Shown according to Figure 4a An enlarged cross section of the clamping device;

[0054] Figure 5a shows the appearance of a third embodiment of an electric heating device having a fifth variation of the first type of clamping device;

[0055] Figure 5b Shown according to Figure 5a An enlarged cross section of the clamping device;

[0056] Figure 6a shows an exploded view of a fourth embodiment of an electric heating device having a clamping device according to the second type;

[0057] Figure 6b Shown Figure 6a The appearance of the assembled electric heating device;

[0058] Figure 6c Shown Figure 6b A cross-sectional view of a detail of the clamping device;

[0059] Figure 6d Shown Figure 6b An enlarged view of the clamping device in a relaxed state;

[0060] Figure 6e Shown Figure 6e An enlarged view of the clamping device in a clamped state;

[0061] Figure 7a shows the external appearance of a fifth embodiment of an electric heating device having a clamping device according to the third type, wherein the clamping tool is removed from the electric heating device;

[0062] Figure 7b Shown Figure 7a The appearance of the electric heating device with the clamping tool inserted therein;

[0063] Figure 7c Shown Figure 7b An enlarged view of the clamping device in a relaxed state;

[0064] Figure 7d Shown Figure 7c An enlarged view of the clamping device in a clamped state;

[0065] Figure 8a A clamping device with a first variant of a recess is shown;

[0066] Figure 8b A second variant of the clamping device with a recess is shown;

[0067] Figure 8c A third variation of the clamping device with a recess is shown;

[0068] Figure 8d A fourth variation of the clamping device having a recess is shown; and

[0069] Figure 8e A fifth modification of the clamping device having a recess is shown. DETAILED DESCRIPTION

[0070] Figure 1a An exploded view is shown, and Figure 1b The outer appearance of a first electric heating device 100 is shown with a clamping device 120 according to a first type. The connecting lines for supplying power to the electric heating device 100 are provided with reference numeral 140 .

[0071] The electric heating device 100 essentially has the shape of a hollow cylinder having a slot extending through the hollow cylinder along a direction predetermined by the cylinder axis, which defines the axis A of the hollow cylinder's axial opening. This slot forms a recess 111. The electric heating device 100 includes a clamping sheath 110, which also forms the outer sheath of the hollow cylinder. This outer sheath is connected to the inner sheath 104 of the hollow cylinder via lateral boundary surfaces 102 and top and bottom boundary surfaces 103 of the slot forming the recess 111. An electric heating element (not visible in the figure) is arranged in the interior space defined by these sheaths or boundary surfaces. This electric heating element is embedded in a well-heat-conducting powder or granules and is electrically insulated from the sheaths or boundary surfaces.

[0072] The various parts of the clamping device 120 are Figure 1d As is particularly clear in the figure, the clamping device 120 has a disk 121, into which a tool receptacle 122, designed here for a screwdriver, is introduced, and the disk 121 is rotatably mounted about an axis of rotation D perpendicular to the cylinder axis A. Engagement means 123 are provided on the disk 121, which taper from their end facing away from the disk 121 in the direction of the disk 121. The associated complementary engagement means 114 are recesses introduced into the push-in element 125, the wall slope of which is adapted to the taper of the engagement means 123, thereby forming an undercut which is formed at the bottom of the disk 121. Figure 1c The disk 121 can be clearly seen and identified in the cross-sectional view of FIG. The push-in member 125 is respectively pushed into the corresponding recess 119 of the clamping sleeve 110 up to the stop 113 and is fixed there by the projection 112.

[0073] If disk 121 is Figure 1b If the engaging means 123 is rotated clockwise from the open starting position shown, it slides along the recess at the wall section 126, but this wall section is curved less than the arc of a circle whose radius corresponds to the distance between the axis of rotation D and the starting position of the engaging means 123. As a result, a force is exerted on the push-in elements 125, which moves them relative to each other and is transmitted to the clamping sheath 110 via the stop 113; the width b of the slot forming the recess 111 decreases.

[0074] Should be counted as the same type of clamping device 120 ' Figure 1eThe main difference between the variant shown in FIG1 is that the complementary engagement means 114′ provided on the push-in element 125′ is implemented as a protrusion, while the engagement means 123′ provided on the disk 121′ is implemented as a kidney-shaped opening that is point-symmetrically opposite to the rotation axis D. The kidney-shaped opening has a curvature smaller than that of a circular arc whose radius corresponds to the distance between the rotation axis D and the starting position of the complementary engagement means 114′. Therefore, the distance between the point-symmetrically positioned end regions of the engagement means 123′ is greater than the distance between their centers, so that the rotation of the disk 121′ forces the width of the recess 111′ to change.

[0075] according to Figure 2 The function of a clamping device of the first type can be illustrated again based on a second variant of such a clamping device 220, which has a disk 221 with a tool receptacle 222 and an engagement device 223 designed as a pin connected to the disk 221. Three different arrangements of the clamping device 220 are shown here from top to bottom, specifically viewed from above on the left side and from below on the right side.

[0076] The complementary engagement means 214, into which the pin engages, are curved slots in the clamping sleeve 210. These extend on different sides of a recess 211 formed as a slot, extending through the clamping sleeve 210, and are point-symmetrical with respect to the axis of rotation D of the disk 221. Specifically, they extend such that the distance between their end regions 214a, which are closer to the recess 211 formed as a slot, is smaller than the distance between their end regions 214b, which are further away from the recess 211 formed as a slot. If the pin now slides from the end region 214a of the complementary engagement means 214 in the direction of the end region 214b due to the rotational movement of the disk 221, the width b of the slot 211 decreases, and thus a clamping force is exerted.

[0077] exist Figure 3a and Figure 3b The first type of clamping device 310 shown in FIG is an example of a structure that ensures very simple assembly of the clamping device 310. The complementary engagement means 314 are also curved slots in the clamping sheath 310. These slots extend on different sides of a recess 311 formed as a slot extending through the clamping sheath 310 and are point-symmetrical with respect to the axis of rotation D of the disk 321. Specifically, they extend such that the distance between their end regions 314a closer to the recess 311 formed as a slot is smaller than the distance between their central sections 314b further away from the recess 311 formed as a slot. However, these slots are located in a recess 319 introduced into the clamping sheath 310 for receiving the disk 321, so that the clamping device 310 does not increase the diameter of the electric heating device equipped with it.

[0078] The engagement means 323 here has a roughly L-shaped form, with the vertical beam of the L formed by the rod-shaped fastening section 323a and the lead-through section 323b, and the horizontal beam of the L formed by the raised section 323c. After the disk 321 is placed in the recess 319, the engagement means 323 are respectively led through from the interior of the clamping sheath 310 by complementary engagement means 314, each designed as a slot, so that the raised section 323c engages behind the edge of the slot, the lead-through section 323b extends through the slot, and the fastening section 323a engages in the fastening openings 325 arranged in the disk. The fastening section 323a then simply needs to be fastened to the disk 321.

[0079] Figure 4a The outer appearance of a second electric heating device 400 is shown, which has a clamping sheath 410, a recess 411 implemented as a slot and three clamping devices 420. In the clamping sheath 410, a groove 419 is introduced, into which an electric pipe spiral is introduced as an electric heating element 418.

[0080] The clamping device 420 with the disc 421, the tool receiving portion 422, the engagement means 423 and the complementary engagement means 414 is implemented according to another variant of the first type, such as can be combined with Figure 4b As can be easily seen from the cross-sectional view of the clamping device 420 in FIG. 1 , the clamping device 420 substantially corresponds to the clamping device according to Figure 1e Therefore, the reference numerals can be Figure 1e The reference numeral ' is omitted and 300 is added. The difference is that the complementary engagement means 414 is placed onto the clamping sheath 410 and is not pushed into the clamping sheath 410.

[0081] Here, in Figure 4a Also shown is a connecting wire 440 for supplying power to the electric heating device 400 .

[0082] Figure 5a The external appearance of a third electric heating device 500 is shown, which has a clamping sheath 510, a recess 511 implemented as a slot, and three clamping devices 520. The clamping sheath 510 surrounds an electric heating element 518 implemented as a wound electric conduit coil.

[0083] If you can combine Figure 5b As can be easily seen in the cross-sectional view of the clamping device 520 in FIG. 1 , the clamping device 520 having the disc 521, the tool receiving portion 522, the engagement means 523 and the complementary engagement means 514 is implemented the same as the clamping device discussed above; their reference numerals are from Figure 4a and Figure 4bThe reference numerals of are obtained by adding 100.

[0084] Figure 6a An exploded view is shown, and Figure 6b The outer appearance of another electric heating device 600 having a clamping device 620 according to the second type is shown. Here, the connecting lines for supplying power to the electric heating device 600 are provided with reference numeral 640.

[0085] The electric heater 600 essentially has the shape of a hollow cylinder with a recess 611, also embodied as a slot, extending through the hollow cylinder along a direction predetermined by the cylinder axis, which forms the axial opening of the hollow cylinder, axis A. The electric heater 600 includes a clamping sheath 610, which also forms the outer sheath of the hollow cylinder. This outer sheath is connected to the inner sheath of the hollow cylinder via lateral boundary surfaces 602 and top and bottom boundary surfaces 603 of the recess 611, embodied as a slot. An electric heating element (not visible in the figure) is arranged in the interior space defined by these sheaths or boundary surfaces. This electric heating element is embedded in a well-conducting powder or granules and is electrically insulated from the sheaths or boundary surfaces.

[0086] The parts of the clamping device 620 are Figure 6a Exploded diagram and Figure 6c As is particularly clear from the cross-sectional view of FIG, the clamping device 620 comprises a disk 621 into which a tool receptacle 622, designed here for a screwdriver, is incorporated, and the disk 621 is rotatably mounted about a rotation axis D perpendicular to the cylinder axis A. For this mounting, a recess 619 is arranged in the clamping sheath 610, in which two guide pins 618 are arranged point-symmetrically with respect to the rotation axis D. The disk has two circular arc-shaped through-holes 629, which are also arranged point-symmetrically with respect to the rotation axis D. The distance between the through-holes 629 corresponds to the distance between the guide pins 618, and the dimensions of the through-holes 629 are such that the guide pins 618 are guided in the through-holes 629 and arranged in the recesses 619, wherein the guide pins 618 are supported in the through-holes 629.

[0087] Furthermore, the disk 621 has, on its side facing the recess 611 embodied as a slot, an engagement means 623, which is embodied here as a curved slot, the distance of which from the edge of the disk 621 continuously increasing from one end thereof to the other end thereof. Due to this structure, when the disk 621 rotates about the axis of rotation D, with the guide pin 618 guided in the through-hole 629, the distance between the closest point of the curved slot of the engagement means 623 and the recess 611 embodied as a slot changes.

[0088] The complementary engagement means 614 is here a metal strip that bridges the recess 611, which is implemented as a slot. The angled first end 614a of the metal strip is connected to the clamping sheath 610 by engaging it in the opening 617. The second end 614b of the metal strip, which is arranged on the other side of the recess 611, which is implemented as a slot, has a pin 614c that engages in the engagement means 623 of the disk 621, namely the curved slot.

[0089] As in Figure 6d and Figure 6e As can be seen particularly clearly in the figure, since, during the rotation of the disk 621, as already explained above, the distance between the point of the curved slot forming the engagement device 623 and the recess 611 implemented as a slot changes, the position of the pin 614c from the recess 611 also changes, and the resulting tensile effect is transmitted to the other side of the recess 611 implemented as a slot through the metal strip forming the complementary engagement device 614, which results in a reduction in the width b of the recess 611.

[0090] Figures 7a to 7d A fifth embodiment of an electric heating device 700 is shown having a clamping device 720 according to the third type.

[0091] The electric heating device 700 is essentially in the form of a hollow cylinder having a recess 701 which is also implemented as a slot and which extends through the hollow cylinder along a direction of extension predetermined by the cylinder axis A forming the axial opening of the hollow cylinder. The electric heating device 700 is essentially similar to Figure 1a and Figure 1b The electric heating device 100 shown has an outer sheath which simultaneously forms a clamping sheath 710 which is connected to an inner sheath 704 of a hollow cylinder via lateral boundary surfaces 702 and top and bottom boundary surfaces 703 of a recess 711. An electric heating element 178 is arranged in the interior space defined by these sheaths or boundary surfaces, the end section of which is located at Figure 7a and Figure 7b As can be seen in FIG. 1 , the electric heating element 178 is embedded in a powder or granules that conducts heat well and is electrically insulated from the sheath or boundary surface.

[0092] In this third type of clamping device 720, the clamping sleeve 710 has a bearing 719 which defines a rotation axis D perpendicular to the cylinder axis A of the hollow cylinder, so that a part 750 of the clamping device 720 having a tooth structure 751 on its circumference can be rotatably supported in the bearing 719. In addition, the clamping sleeve 710 has a complementary engagement device 714 which is provided at the bottom of the clamping sleeve 710. Figure 7c and Figure 7dThe partially opened view of the electric heating device 700 can be seen particularly clearly and is implemented here as a recess in the outer jacket of the electric heating device 700, which recess increases in distance from its first end 714a to its second end 714b of the recess 711 implemented as a slot. Figure 7d It can be seen in Figure 7c is covered in the Figure 7c It can be seen in Figure 7d Covered in.

[0093] The clamping device 720 also includes a clamping slide 740. The clamping slide 740 has an engagement means 743, which is formed here by a subsequently welded projection, which is guided in a recess and thus engages with a complementary engagement means 712 of the clamping sheath 710. The clamping slide 740 also has an opening 741 extending parallel to the axis A of the axial opening, which has at least one edge extending parallel to the axis A of the axial opening, which has a toothing 742 complementary to the toothing 751 and through which the bearing 719 is exposed.

[0094] The clamping slide 740 further bridges the recess 711, which is implemented as a slot. Since the clamping slide 740 is designed in a sleeve-like manner and is adapted to the clamping sheath 710 in the relaxed state, the clamping slide 740 contacts the clamping sheath 710 on the side of the recess 711 opposite the engagement device 743, or can contact the clamping sheath 710 at least during the clamping process.

[0095] As a result of this arrangement, when the part 750 of the clamping device 720 having the tooth structure 751 at its circumference is rotatably supported in the bearing 719 and rotates, as shown in FIG. Figure 7c and Figure 7d As shown, the interaction of the toothing 751 with the complementary toothing 742 causes the clamping slide 740 to be displaced axially and thereby the width b of the recess 711 embodied as a slot to change at least over a portion of the axial displacement path.

[0096] In particular, for the third type of clamping device 720, there is the possibility that the part 750 of the clamping device 720 having the tooth structure 751 on its circumference is not permanently arranged on the electric heating device 700, but only when a change in the clamping effect is to be brought about. In particular, that is to say, the part 750 of the clamping device 720 having the tooth structure 751 on its circumference can be formed by a tool which, in the simplest case, is Figures 7a to 7d Shown is a star wrench only.

[0097] Figures 8a to 8eThe clamping devices 10, 20, 30, 40, 50 shown with the clamping sheaths 11, 21, 31, 41, 51 and the disks 14, 24, 34, 44, 54 are intended to illustrate some of the different shapes that the recesses 12a, 12b, 22a, 22b, 32, 42, 52 can have within the meaning of the present disclosure. It should be emphasized here that, although in the variants shown here the width of the recess is always relatively small compared to its length, this is not absolutely necessary.

[0098] Specifically, according to Figure 8a Provided in the clamping device 10 of FIG. 1 are two recesses 12 a, 12 b which extend largely parallel to one another, but start from opposite ends of the clamping device 10 and end shortly before the respective other end of the clamping device 10 .

[0099] And according to Figure 8b In the clamping device 20 , there are two recesses 22 a , 22 b , which are arranged collinearly, but both do not originate from the end of the clamping sheath 21 , but are formed by two separate openings in the clamping sheath 21 .

[0100] exist Figure 8c In the clamping device 30 shown, there is only one recess 32 , which starts at one end of the clamping sheath 31 and extends only slightly beyond the center of the clamping device 30 .

[0101] Similar to Figure 8d In the example of the clamping device 40 shown in FIG, the recess 42 can also have a section which is wound helically around a section of the clamping sheath 41 .

[0102] according to Figure 8e In the example of FIG. 5 , in addition to the recess 52 introduced into the clamping sheath 51 and embodied essentially identically to the recess 42 , there is a second recess 53 embodied somewhat wider.

[0103] Description of reference numerals:

[0104] 10, 20, 30, 40, 50 clamping devices

[0105] 11, 21, 31, 41, 51 clamping sheath

[0106] 12a, 12b, 22a, 22b, 32, 42, 52, 53 recess

[0107] 14, 24, 34, 44, 54 disks

[0108] 100, 400, 500, 600, 700 electric heating device

[0109] 102, 103, 602, 603, 702, 703 boundary surfaces

[0110] 104, 604, 704 inner sheath

[0111] 110, 210, 310, 410, 510, 610, 710 clamping sheath

[0112] 111, 211, 311, 411, 511, 611, 711 recess

[0113] 112 raised part

[0114] 113 stopper

[0115] 114, 114′, 214, 314, 414, 514, 614, 714 complementary engagement devices

[0116] 119, 319, 619 Depression

[0117] 120, 120′, 220, 320, 420, 520, 620, 720 clamping device

[0118] 121, 121′, 221, 321, 421, 521, 621 disk

[0119] 122, 122′, 222, 322, 422, 522, 622 Tool Storage

[0120] 123, 123′, 223, 323, 423, 523, 623, 743 Jointing device

[0121] 125, 125' push piece

[0122] 126 wall segments

[0123] 140, 440, 640 connecting wires

[0124] 214a, 214b, 314a, 314b end regions

[0125] 323a Fastening section

[0126] 323b conductive section

[0127] 323c raised section

[0128] 418, 518, 718 electric heating elements

[0129] 419 Groove

[0130] 614a, 714a first end

[0131] 614b, 714b second end

[0132] 614c pin

[0133] 618 guide pin

[0134] 629 Perforation

[0135] 719 bearings

[0136] 740 Clamping Slide

[0137] 741 Opening

[0138] 742 complementary tooth structure

[0139] 750 parts

[0140] 751 tooth structure

[0141] A axis

[0142] D Rotation axis

[0143] b width

Claims

1. An electric heating device (100, 400, 500, 600, 700), comprising: an axial opening for receiving an object to be heated; an electric heating element (418, 518, 718); and a cylindrical or truncated cone-shaped clamping sheath (110, 210, 310, 410, 510, 610, 710) for generating an adjustable force acting radially in the direction of the axis (A) of the axial opening, wherein: At least the clamping sheath (110, 210, 310, 410, 510, 610, 710) of the electric heating device (100, 400, 500, 600, 700) is penetrated by at least one recess (111, 211, 311, 411, 511, 611, 711), the width (b) of the recess can be changed by means of at least one clamping device (120, 220, 320, 420, 520, 620, 720), characterized in that at least one part of the clamping device (120, 220, 320, 420, 520, 620, 720) is arranged relative to the clamping sheath (111). 0, 210, 310, 410, 510, 610, 710) is rotatably supported or rotatably supported about a rotation axis (D) perpendicular to the axis (A) of the axial opening, wherein this component interacts directly or indirectly with the clamping sheath (110, 210, 310, 410, 510, 610, 710) in such a way that a rotation of the rotatably supported or rotatably supported component of the clamping device (120, 220, 320, 420, 520, 620, 720) changes the width (b) of the recess (111, 211, 311, 411, 511, 611, 711), Characterized in that the rotatably supported or rotatably supported part of the clamping device (120, 220, 320, 420, 520, 620) is a disk (121, 221, 321, 421, 521, 621) having at least one engagement device (123, 223, 323, 423, 523, 623), wherein the engagement device (123, 223, 323, 423, 523, 623) interacts with at least one complementary engagement device (114, 214, 314, 414, 514, 614) arranged on the clamping sheath (110, 210, 310, 410, 510, 610).

2. The electric heating device (100, 400, 500, 600, 700) according to claim 1, characterized in that: The engaging means (123, 223, 323, 423, 523, 623) is a convex portion and the complementary engaging means (114, 214, 314, 414, 514, 614) is a concave portion, or the complementary engaging means (114, 214, 314, 414, 514, 614) is a convex portion and the engaging means (123, 223, 323, 423, 523, 623) is a concave portion.

3. The electric heating device (100, 400, 500, 600, 700) according to claim 2, characterized in that: The protrusion is formed by a member fastened to the disk (121, 221, 321, 421, 521, 621) or a member fastened to the clamping sheath (110, 210, 310, 410, 510, 610).

4. The electric heating device (100, 400, 500, 600, 700) according to claim 2, characterized in that The protrusion and the depression contact each other at least sectionally using undercuts, thereby fixing the disk (121, 221, 321, 421, 521, 621).

5. The electric heating device (100, 400, 500, 600, 700) according to any one of claims 2 to 4, characterized in that: The depression extends in a curved manner.

6. The electric heating device (100, 400, 500, 600, 700) according to claim 5, characterized in that: The curvature of the recessed portion changes.

7. The electric heating device (100, 400, 500, 600, 700) according to any one of claims 2 to 4, characterized in that: The recess forms the complementary engagement means (114, 214, 314, 414, 514, 614) arranged at the clamping sheath (110, 210, 310, 410, 510, 610) and extends in a separate part fixed at the clamping sheath (110, 210, 310, 410, 510, 610).

8. The electric heating device (100, 400, 500, 600) according to any one of claims 1 to 4, characterized in that: The clamping device (120, 220, 320, 420, 520, 620) has a tool receiving portion (122, 222, 322, 422, 522, 622), which is located on the rotation axis (D) of the rotatably supported part of the clamping device (120, 220, 320, 420, 520, 620, 720).

9. The electric heating device (100, 300, 600) according to any one of claims 1 to 4, characterized in that: The clamping sheath (110, 310, 610) has a recess (119, 310, 619), in which the clamping device (120, 320, 620) is arranged at least in sections.

10. The electric heating device (600) according to claim 1, characterized in that: The complementary engagement device (614) arranged at the clamping sleeve (610) bridges the recess (611), has a first end (614a) on one side of the recess (611), and has a second end (614b) on the other side of the recess (611), the first end (614a) being connected to the clamping sleeve (610), and the second end (614b) being directly or indirectly engaged in the disk (621), or the disk (621) being engaged in the second end (614b).

11. The electric heating device (700) according to claim 1, characterized in that: The clamping sleeve (710) has a bearing (719) which defines an axis of rotation (D) perpendicular to the axis (A) of the axial opening, so that the part (750) of the clamping device (720) having a tooth structure (751) at its circumference can be rotatably supported in the bearing (719), and the clamping sleeve (710) also has complementary engagement means (714) which increase in distance from its first end (712a) to its second end (712b) of the recess, and the clamping device (720) also has a clamping slide (740), wherein the clamping slide (740) bridges: - engagement means (743) which engage with said complementary engagement means (714) of said clamping sheath (710); an opening (741) extending parallel to the axis (A) of the axial opening, the opening (741) having at least one edge extending parallel to the axis (A) of the axial opening, the edge having a toothing (742) complementary to the toothing (751), and the bearing (719) being exposed, so that the component (750) is arranged or can be arranged in the bearing (719); - said recess (711); and the clamping slide (740) is in contact or can be in contact with the clamping sheath (710) on the side of the recess (711) opposite the complementary engagement means (714), Thus, when the component (750) of the clamping device (720) having the tooth structure (751) at its circumference is rotatably supported in the bearing (719), and is axially displaced by the interaction of the tooth structure (751) with the complementary tooth structure (742) of the clamping slide (740), the width (b) of the recess (711) is changed at least over a portion of the axial displacement path.

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