Lifting device

The invention relates to a lifting device, particularly for a supporting and Support means as for the drawbar of vehicle trailers or the like. after the preamble of the patent claim. 1

In the agricultural sector or in other areas where uniaxial Car trailers are used, there is the problem that the unhitched the trailer vehicle tilts and the outermost end the pole on the ground rests, so that then for coupling by hand this has to be lifted and the clutch are supplied to the vehicle have to be. This is depending on the size and loading condition of the vehicle trailer possible difficulty or not at hand or even by using a third party.

This problem also occurs in two-axle vehicle trailers whose Axes are so close together that they transport connections as Einachser be treated or with other trailers with a rigid drawbar. Here, the drawbar from touching the ground does not necessarily, but it is in the Usually not at the right height, problemios hitched to the vehicle will.

To resolve this issue, several lifting devices are developed been, bring the tiller to the desired height. So are simple Outriggers known which hold the tiller at a certain height, so that only a relatively small lifting work must be done, but these Supporting feet not completely prevent the tipping of the vehicle trailer. This standing or support feet can be rigid or foldable and be provided with a wheel to simplify maneuvering by hand. Also stands are known which are adjustable in height by a hand crank, so that the force required for performing the lifting operation is very low. though is the time required for the lifting and lowering relatively large because the gear ratios accordingly due to the desired low expenditure of energy had to be chosen.

The generic document US 3,595,527 discloses a lifting device with a Sliding gate with three nested tubes and a Handle for moving the pipes. The handle is a simple run folding lever in from a rest position if needed Working position is pivotable. He is over in its respective location Latching elements secured.

In other areas, there is the problem that support and bearing means must be supported vertically adjustable. It may by wall parts, frame parts, stand fittings and other devices act, which often simply performed a quick height adjustment to which then held a load after adjustment shall be.

It is therefore an object of the present invention, a lifting device create, which allows a quick and easy height adjustment perform, in each set altitude secure retention and lifting should be possible.

This object is achieved by the features indicated in claim 1.

With such a device it is possible to the desired altitude relatively accurate to choose and also the intended fine adjustment over the accurately adjust handle invention. The fine adjustment can possibly even be made under load. This combination with a lockable height rough adjustment and a viable by rotation Fine adjustment has been provided a lifting device for all applications is designed as well to handle as well as resilient.

In particular, a holding device is thus gestaltbon with which it is possible is the pole of a vehicle trailer with little force and time required in the desired position (altitude) for connecting and detaching of to bring a tractor.

For this purpose, it is provided the drawbar of vehicle trailers be equipped with a holding and lifting device, which stand one, a wheel or the like. and having a height adjuster and the has a fast altitude coarse adjustment and a fine height adjustment.

For this purpose, a stand is provided, which from an elongate metal profile exists which is at one end in such a way articulated on the drawbar, that the Axis of rotation at right angles to the drawbar and at the other end is of Stand is a roll-off device mounted, the height adjuster consists of telescoping tubes, of which the outermost Tube is rotatably mounted on the drawbar and a first inner tube slidably receives comprising notches on its outer side, in the at least one pawl which is articulated to the outer tube, snapped is, wherein in the first inner pipe a further inner tube or inner rod is arranged at one end of the base adjacent to the unwinding, is connected and the like via a thread. slidably in the inner tube and can be fixed. Instead of the pawls can also be displaced use locking pins or institutions sharing the same mode of action will.

By this configuration, it is possible, the way the is necessary in order to bring the foot in contact with the ground or conversely, very quickly to cope, since the height adjustment does not have the Turning a handle to the displacement of the two inner tubes against each other must be made, but only by manually loosening the pawls from the locking position, so that the inner tubes by displacing the outer tube very quickly bring the stand with the ground contact. The rest of the lifting work is done conventionally with the handle, since more Forces must be applied.

The handle of the invention for conventional height adjustment according to a preferred Embodiment configured as a hand crank which advantageously has a Kurbelarretierung so that, by vibrations during driving operation occur, the hand crank does not move. For this purpose, it is provided on the outer periphery of the first inner tube to crank out teeth to arrange to form a grid wreath. To lock engages locking bolt, the part of the hand crank, is a grid in the wreath. By manual Operating the winch, that is by pressing down the locking bolt removed from the locking position in the grid rim, so that by rotating hand crank height fine adjustment can be carried out.

For the positioning of the locking bolt, the winch according to two be configured preferred embodiments.

For this purpose, according to the one embodiment, provided that the crank handle has a knob, the opposite for operating the winch the Force a arranged in its interior spring is depressed, wherein a rocker inside the winch the locking pin from the grid Wreath pulls out.

After another embodiment, the winch itself is a rocker formed, which is pressed down against a spring force, wherein the end fixed locking pin is out of the grid ring.

The pivot point of the rocker is in the point at which the hand crank to the threaded rod is hinged.

According to another embodiment of the handle or is this a Hand crank formed such that the height fine-adjustment, the crank handle no longer has to describe a full circle, but that partial circles suffice what especially in confined spatial conditions beneficial is. For this purpose the grid ring is fixed to the threaded rod, while the hand crank is connected via a free-wheel with the threaded rod as a fulcrum is. the locking pin is in the engagement of the grid ring, so can be moved by turning the hand crank of the grid ring and there is a height adjustment. The grid ring is a plain compared to the first inner tube set. Pressing the hand crank is released to the grid Wreath connection.

Thus, by a "reciprocal move" the height adjustment effected.

According to a further embodiment of the height rough adjustment, it is provided that the outermost pipe of the displaceable also of interfolded Tubes existing lifting device on the drawbar fixed or hinged is. In the outermost tube an inner tube is mounted, consisting of the outermost tube protrudes on the pole opposite side and a wheel or the like. wearing. In the inner tube is a threaded rod, the facing on the pole side of the two tubes of this protrudes, which he compared to the outer tube via a slide bearing in its position is fixed.

On the protruding portion of the threaded rod, the handle is attached.

The inner tube relative to the threaded rod by means of a threaded body supported the in through passage openings in the inner tube Thread of the threaded rod engages. The threaded body is according to one embodiment at least divided in two, preferably it consists of four segments. The protruding from the inner tubular part of these segments a pressure ring against spring force hineindrückbar wherein both thread interlink. If the pressure ring, which is preferably actuated by a rotation is, in the position in which it does not, the segments of the threaded rod suppressed so can for quick height adjustment, the inner tube, the now independent can be moved from the threaded rod, are so far removed, that the support wheel or the like. touches the ground. Subsequently, the brought back segments of the threaded body for engagement with the threaded rod, so that now be the height fine adjustment by means of the handle can.

The operation is preferably carried out via a handle, by a vertical slot directly engages the outer tube to the pressure ring.

Advantageously, the thread of the threaded rod and / or the Segments of the threaded body square or tapered inwardly be designed with respect to the edge shape of the threads. Thereby the segments are pressed under load against the threaded rod so that an automatic backup of the threaded body to prevent accidental release the threaded rod is.

The embodiment with the segmented threaded body can also by a device having a two-piece nut, the threaded rod the are covered on all sides, replaced. The two arms of the mother are in a be stored and housing displaced by spring force against the pressed threaded rod so that the handle has a height fine adjustment can be made. Regarding the amount rough adjustment nut parts are against the spring force by means of corresponding handles of the threaded portions pulled away, so that the housing with the split nut and the drawbar can be adjusted independently of the handle of the threaded rod.

Instead of the threaded body, it is also possible for two mutually screwable to use nuts. One of the nuts in this embodiment has only two to areas of a thread on each ca. 90 ° have. Correspondingly, also the threaded rod is formed so that opposite with a rotation of 90 °, a clearance of the corresponding nut the thread is achieved and can be carried out the height adjustment. subsequently bringing the mother to engage again with the other Mother saved that can be kept fixed appliances.

Additional securing both nuts can by means of a securing bolt done.

Another height Coarse adjustment is provided by the fact that the Threaded rod one side is comprised of a nut body by a Opening in the inner tube is guided and against spring force from the threaded rod can be separated, so that a free displacement is given. The threaded rod can also be of another mother on the body free half side are covered, in which case, via an appropriate device for example, a universal joint, disconnect the first nut body from the threaded rod also by means of a handle of the second half-page parent body is subtracted from the threaded rod.

Such a universal joint or the like. is in all embodiments with a two or more part parent or threaded body used.

In the embodiments of the apparatus that a have support wheel, a device for automatic positioning and fixing the support wheel are provided in the driving mode, so eg Advantageously, the supporting wheel about a vertical axis while driving rotates. For this purpose it is provided adjacent to the second inner tube to wheel to attach a small wheel whose axis of rotation at right angles to second inner tube is. The positioning of this wheel is carried out in such a way that the wheel is pointing in the direction in which the support wheel is to be fixed.

Furthermore, the lower edge of the first inner tube is bevelled. If now the support wheel pulled up, so the small wheel running on the beveled Edge to the highest point of the slope. is in this position automatically rotated and fixed the wheel.

Hereinafter, the invention using the single figures in the Drawing explained. It shows in a purely schematic representation<sl><li>FIG. 1 in a partially sectioned side view of a Lifting device in the unloaded condition;</li><li>FIG. 2 in a partially sectioned side view of a Lifting device in the extended state;</li><li>Fig. 3 in a partially cut side view of a possible embodiment the height adjustment;</li><li>Figure 4 is a partial view of another embodiment of the height adjustment means.</li><li>Fig. 5 in a partially sectioned side view of a Lifting device according to another embodiment;</li><li>Figure 6 in a longitudinal section a detailed view of Fig. 4.</li><li>FIG. 7 shows in a cross section a detailed view of Fig. 4;</li><li>Fig. 8 in a sectional detail view of another embodiment a device for height Coarse adjustment;</li><li>Fig. 9 and 10 in a sectional detail view of a further embodiment a device for height Coarse adjustment;</li><li>Fig. 11 in a partially sectioned detail view of a further embodiment a device for height Coarse adjustment;</li><li>Fig. 12 in a partially sectioned side view of a Lifting device with the handle according to the invention and a device for automatic positioning of a support wheel;</li><li>Fig. 13 in a partially sectioned side view of an embodiment another handle according to the invention; </li><li>Fig. 14 in a sectional side view of a modification, a Lifting device according to the invention; and</li><li>Fig. 15 in a partially sectioned plan view of a modification, the embodiment of Fig. 8.</li></sl>

Figures 1-11, 14 and 15 show preferred lifting devices and height adjusting means such as, for example, from EP 06 88 687 is known, whereas the figures 12 and 13 order Handblaben invention to vorbeschreibenen Heber devices.

The lifting apparatus 100 shown in FIGS. 1 and 2 is connected to a drawbar set 10 of a vehicle trailer, not shown, and includes a Height adjustment means 11 and a base 12. The drawbar 10 has to of the vehicle side facing a cross beam 13 at 14, on which a unillustrated clutch for the vehicle can be secured. To the cross member 14 12 is hinged to one end 15 of the base. At the opposite End 16 of the base 12, a rolling plate 17 is provided. The Height adjusting means 11 consists of an outer tube 18, which at the Drawbar 10 is hinged at point A. In the outer tube 18 is a first inner Tube 19 slidably mounted, said from the outer tube 18 only a small portion is encompassed. On the outer side 20 of the first inner Tube 19 are notches 21, 22 inserted, engage in the ratchet pawls 23, 24th The pawls 23, 24 are held by a holder 25, 26 and loaded by a spring 27, 28 such that the angled portion 29, 30 of the pawls 23, 24 to the outer surface 20 of the first inner tube 19 or in the respective notch 21, are pressed 22nd The notches 21, 22 are not at the same height, relative to the longitudinal axis L of the first inner Pipe 19, but offset from each other located so that only a locking pawl 23 engages the respective notch 21, while the other Pawl 24 rests on the outside of the twentieth is one in said first inner tube 19 further inner tube (innermost inner tube) is introduced 31, which on the the Stand protrudes 12 facing the end 32 of the first inner tube 19 is adjacent and the stand 12 is hinged to the rolling plate 17 at 32a. Said first inner tube 19 and the further inner pipe 31 are connected by a Handle 33 relative to each other. The handle 33 consists of a Winch 34 and a threaded rod 35, the corresponding in a Thread 36 of the other inner tube 31 engages, it means a The sliding bearing 37, which is fixed on the threaded rod 35, opposite the first inner tube 19 is supported. The pawls 23, 24 are each provided with a grip-like handle 38, 39 is provided, with the release of the pawl 23, 24 conducted out of engagement in the notch 21, 22nd This is necessary, if the export length to be shortened while the extension without Actuation of the handle is possible because the shape and aufprund Geometry the pawls 23, 24 dodge against the spring force.

In the embodiment of height adjuster part means purely schematically in FIG. 4 11, the same structure is principally provided, the pawls 23, 24 are formed as locking pins 40, 41, in a Housing out 42 and supported against the housing 42 springs held 27, 28 in their movement of the tube 19 blocking detent will. The hinged at 43 to the pipe 19 pivoting lever-type handle 44 acted upon pivotal movement sequentially stop rings 45, 46, with the stop ring 45 arranged on the locking pin 41 is. offset by two to each other in the direction of the longitudinal axis L arranged locking pins 40, 41 to reach a precision ratchet system. The the Raster Profile forming notches 21 can thereby each other in greater distance to be ordered. The advantage is greater stability.

At 47 designed as a recessed groove notch for transportation is provided.

In all embodiments, the height adjustment means 11 is provided, that Eingreifspitzen 51 of the pawls 23, 24 a on one side have inclined plane 52 to an automatic unlocking when appropriate to allow the tube Bewequng 19th

By the two locking pawls 23, 24 is also in all embodiments reaches a narrow spacing. All embodiments may at be used all uses.

The lifting device 200 of FIG. 5 consists of an outer tube 210 fixed to a pole not represented at an appropriate angle connected is. In the outer tube 210 is slidable an inner tube 211 stored, which at the end remote from the drawbar 212 of the outer tube 210 protrudes. At the projecting part 213 of the inner tube 211 is fixed a wheel 214th Inside of the inner tube 211 is a threaded rod 215 mounted, the support wheel 214 from the opposite protruding end 216 of the inner tube 211 and the outer tube. At the outer tube 210 is the threaded rod 215 by means of a sliding bearing 217 axially fixed and rotatably mounted. In the region 218, the bearings from 217 is covered, has the threaded rod 215 no thread. These range 218 is followed by a handle in the form of a hand crank 219th The inner tube 211 is relative to the threaded rod 215 by means of a threaded body 220 supported (Figs. 6 and 7).

Given by 211 through openings 221 are incorporated in the inner tube, by the segments 222 of the threaded body 220 to the threaded rod 215 are performed.

The outwardly projecting part of the segments of a circumferential pressure ring 223, said segments 222 a horizontal extending groove 224 have applied to a corresponding spring 225 the inner wall 226 of the pressure ring 223 corresponds. The pressure ring 223 comprising the segments 222 on three sides. The segments 222 are means a compression spring 227 which at the inner tube 211 and the respective Segment 222 is supported, pushed away from the thread 228 of the threaded rod 215, so that the thread 228 of the threaded rod 215 and the thread 229 the threaded body 220 does not come into contact. Thus, the pressure ring 223 can be actuated, is in the outer tube 210, a vertically extending Slot 223a provided by a handle is guided 223b by means of the pressure ring 223 is operated.

The contact is made by twisting of the pressure ring 223rd Thereby is the respective segment 222, which in a corresponding recess 230 rests on the inner wall 226 of the pressure ring, by subjecting the Segment 222 with pressure by a slope 231 in the recess 230 Direction of the inner tube 211 leads, with the threaded rod 215 in contact brought.

Fig. 8 shows a device for connecting the threaded rod 215 with the inner tube, which instead of the embodiment with the threaded body 220 is used and the pressure ring 223rd

For this purpose, a two-part nut body 232 is provided, which the threaded rod 215 surrounds on all sides. The two parts 233, 234 of the nut body have 232 merged in a rectangular shape and are in a Housing 235 mounted horizontally displaceable, wherein the housing 235 in the right angle to the threaded rod 215 is fixed to the inner tube 211th

The two parts 233, 234 are each by means of a compression spring 236, is supported on the housing 235 and a portion 233 and 234, respectively, to the threaded rod 215 is pressed and brought into contact with this. The parts 233, 234 of the The nut body 232 are connected to a drawing axis 237 on the threaded rod 215 opposite side attached, provided. This drawing axes 237 be led out of the housing 235 and are there with a handle 238 provided.

FIGS. 9 and 10 show a further device for connecting the Threaded rod 215 with the inner tube 211th

Here, the threaded rod 215 has an external thread 239 on the steps of 90 ° is divided in such a way that it alternately areas without and are externally threaded 239th For connection to the inner pipe 211 are two nuts 240, 241 provided, the nut 240 similarly via a divided thread 242 has as the threaded rod 215. Correspondingly Position is this mother 240 freely on the threaded rod 215th The other nut 241 has continuous threads.

The nut 240 with the divided thread 242 has a retracted Field 243 has an external thread 244 onto which the other nut 241 by means of a second internal thread 245 is screwed. One of the nuts 240, 241 is fixed to the inner tube 211th

FIG. 11 shows yet another embodiment of apparatus for Height Coarse or for connecting the threaded rod 215 with the inner tube 211th

Here is the threaded rod 215 of a nut body 245 'in a comprises the range of 180 °. This nut body 245 'is formed by a through hole 246 out in the inner tube 211th The through-hole 246 is covered by a housing 247, in which, inter alia, the nut body 245 is mounted. The nut body 245 'includes the threaded rod 215 remote Page a drawing pin 248, after an opening 249 is led outside and having a handle 250th

The nut body 245 'is a coil spring 251, in the center of Pull Tab 248 is located, pressed against the threaded rod 215th

The coil spring 251 is at the rear 252 of the nut body 245 'and the inner wall 253 of the housing 247 is supported. The Pull Tab 248 may be hinged to the nut body 245 ', in which case it a lateral extension, which is not shown here has, which in a L-shaped groove in the inner wall 253, or at a Z-profile or the like. Start running, so that by rotating the handle 250 a locking possible is.

On the outside 254 of the housing 247, a locking pin 255 is in Form of a rocker is articulated, by means of a compression spring 256 which at the outer side 254 and the threaded rod 215 facing the end 257 of the locking bolt 255 supported, pressed toward the handle 250th there engages a lateral extension 258 of locking pin 255 behind a retaining ring 259, located at the Pull Tab 248th but it can also be provided be that the lateral extension for securing, upon application of the parent body 245 'engages on the threaded rod 215, the handle 250th

In Fig. 12 a lifting device 300 is illustrated, wherein the drawbar and the outer tube are not shown.

The inner tube 310 has a slot profile 311 with notches 312 in accordance the embodiment of Figs. 3 and 4.

In the first inner tube 310, another inner pipe (innermost Inner tube) 313 slidably supported. The other inner tube 313 protrudes on the one side, ie, the bottom side of the first inner tube 310 also. To the outstanding part 314 of the other inner tube 313 is a wheel 315 rotatably mounted.

In the further inner tube 313 a threaded rod 316 is screwed, which protrudes on the side opposite the wheel 315 side. The threaded rod 316 is in a through hole 317 by means of a Slide bearing 318 in the closed side 319 of the first inner tube 310 rotatably mounted. The protruding portion 320 of the threaded rod 316 is pivotally connected with an inventive hand crank 321 with a knob 322nd

In order to connect a coupling member 323 is used. The hand crank 321 and the part 324, which is articulated on the coupling member 323 is over the Fulcrum led out and instructs the rotary knob 322 opposite End a perpendicular fixed thereto Locking 325 on which points in the direction of the inner tube 310th

On the outer periphery 326 of the first inner tube 310 in the area of Top 327 is a gear 328 attached to the locking pin 325 engages. The winch 321 is by spring force in the locked Position held. The spring 329 is the coupling member 323 to a spring retainer 330 and supported on the articulated on the coupling member part 324, wherein the knob from the inner tube 310 is pushed away.

Further, Fig. 12 is a means 331 for automatic positioning the support wheel 315. For this purpose, the wheel to 315 facing lower edge 332 of the first inner tube 310 and the beveled outstanding Part 314 of the other inner tube 313 is provided with a small wheel 333rd The wheel 333 is rotatably supported on an axis 334, at right Angle from the other inner tube 313 projects. If the threaded rod 316 is fully screwed into the other inner tube 313, as is the wheel 333 at the point of the beveled lower edge 332 of which support wheel the 315 farthest away.

FIG. 13 illustrates an embodiment of a winch according to the invention 335 with locking, wherein the winch is 335 fixedly connected to the threaded rod 316th The knob 336 of the hand crank 335 includes a compression spring inside 337 on. About a bolt 338 of the inside of the knob 336 in the part 339 leads which connects the rotary knob 336 with the threaded rod 316, the Knob 336 pivotally connected to a rocker 340th The rocker 340 is in the part 339, which is executed as one-sided open hollow profile arranged, and approximately centrally hinged. The opposite from the bolt 338 End 341 of the rocker 340 has a locking pin 342 which in a point at 343 indicated toothing engages for locking.

It is possible that the pedestal 12 of an elongate metal profile exists which is at one end in such a way articulated on the drawbar 10, that the Axis of rotation of the stand 12 at right angles to the drawbar 10 is, and that at the other end 15 of the base 12 the insurgency or unwinding is fixed and that the outer tube 18 pivotally supported on the Drawbar 10 is articulated.

It is also contemplated that the unwinding of a rounded Rolling plate 17 consists, or that the unwinding device consists of a wheel.

It is also advantageous that the wheel has a locking device.

A variant shows that the pressure ring 223, the segments 222 on three sides, includes.

Also it can be provided that the housing 235 at the inner tube 211 is set.

In particular, that the housing 235 may also be provided to the outstanding from the outer tube 210. Part 213 of the inner tube 211 set.

It is advantageous that the drawing pin 248 at its free end a handle 250 has.

Another embodiment is that the hand crank 321 with is a locking device fitted.

It is proposed that the teeth circumferentially on the outer periphery is formed of the first inner tube 310th

Alternatively, it is possible that the toothing on the first inner arranged tube 310 occlusive circular area to handle toward circumferentially is.

Finally, it is also conceivable that the handle of a freewheel is connected to the threaded rod and that the toothing in the form of a Ring gear is fixedly connected to the threaded rod through the center of the Sprocket is performed.

The in the description and in the appended claims Terms used tubes, inner tubes and outer tubes generally comprise elongated elements corresponding to each other fügbar. For example can internal parts that are referred to as pipe, also massively be designed as a rod or semi solid. It is also possible that as a Threaded rod designated parts not actually solid but only formed partly solid or tubular manner.

In some embodiments, it was stated that a process called foot arranged prior item to internal components. in principle is also a complementary formation conceivable where the foot in the area of The outer tube is mounted. It is also possible, according to a constructional variant, that the outer tube is not on the vehicle or other supporting part was injured, but that the inner tube protrudes from the arrangement is and was injured on the vehicle and that the outer tube telescopically is positioned.

To facilitate a provision, it is possible that relatively telescoping parts by an elastic tension member to couple. For example, it is possible relative to the telescoping element umbeweglichen element or relative to the supporting vehicle or to another carrier, elastic to brace. The elastic strain for example, can take place via an elastic band, at a linear Arrangement are coil springs or similar elements expediently. When using a rubber coating for protection of the material may be a roller type be provided for the elastic deflection. The purpose of this recirculation device It is in a loosening of the quick grid repatriation in the starting position to accelerate. There are therefore in this case no additional Control operations are required.

The dimensioning of the feedback device may according to different Viewpoints done. In addition to the already described dimensioning, in which a return is triggered automatically, it is also possible to design the spring forces such that only compensate for the weight forces will. Upon release the catch would then no automatic Recycling done in a manual return but only minimal applied forces.

Fig. 14 shows an additional variant. In an outer tube 401 is an inner tube 402 arranged which in the region of the outer tube 401 remote interior expansion is threaded 403rd Within of the inner tube 402 is a central tube out 404 within which a spreadable threaded body disposed 405th The threaded body 405 can with its thread profiling by recesses 406 of the central tube 404 be guided and engages in the thread 403 of the inner tube 402.

To carry out the Spreizvorganges of the threaded body 405 is a Actuating element 407 is provided which can be designed as a rod. The Actuator 407 is coupled with an actuating device 408 which either a spreading process of the threaded body 405 performs, or a return the threaded body 405 is caused to the starting position. The expansion process For example, by conical-shaped elements in the area of caused threaded body, which in a longitudinal direction of the setting element 407 slidably. Also can be rotated eccentric Components are used. To prevent displacement of the threaded body 405 is above the threaded body 405, a support member 409 in the central tube 404 used. By the retaining member 409 is the control element 407 passed. An intervention of the threaded body 405 in the Thread 403, it is possible, the central tube 404 by means of a crank 410 to rotate and the central tube 404 to move relative to the inner tube 402nd It is thus possible, first at a separation of threaded body 405 and Thread 403 rapid longitudinal adjustment of central tube 404 and inner tube 402 carry out relative to each other and after engagement of the threaded body 405 into the female thread 403, a fine adjustment using the crank 410 perform.

In FIG. 15 a variant of the embodiment shown in FIG. 8 is indicated. Between the components 233, 234 eccentric elements 420 are arranged, the separation of the threaded body or the two causing parts of the threaded body of the central thread and a relative allow displacement to each other. By using this eccentric 420 is possible without very little disturbance of the function in the Embodiment in Fig. 15, the components 236, 237 to omit 238th It thus there is a considerable simplification of the construction. in principle but it is also conceivable that the eccentric elements 420 additionally arrange, as shown in Fig. 15.