Lifting device including a sledge system axle and a roof window comprising such a lifting device.

Technical Field

The present invention relates to a lifting device for a roof window, in particular for installation in an inclined roof surface, comprising a lifting arm, a spring assembly with a first coupling member, and a sledge system configured to be slidably connected to one part of the roof window and including a sledge and a second coupling member configured to cooperate with the first coupling member, in which a first end of the lifting arm is rotatably connected with the sledge system and a second end is configured to be connected to another part of the roof window. The invention furthermore relates to a roof window incorporating such a lifting device.

Background Art

In roof windows for installation in an inclined roof surface in which the operation takes place either entirely or partially about a top hinge axis, it is known to balance at least part of the weight of the movable components by means of a lifting device inserted between a pair of associated side members of the stationary frame and the sash element, respectively, and having one end pivotally connected with one of the side members while its other end is hinged to a sliding shoe displaceable along the other side member, said shoe being biased by a tension spring in a direction so as to exert an outwardly directed pressure through the lever on the sash element. The purpose of this arrangement is to facilitate opening the window, and the dimensions may be chosen so that the spring can retain the top-hinged frame in equilibrium in a desired opening position.

The biased slide shoe of such lifting devices is mounted on and moves in parallel with or along either the side frame member or the side sash element. The slide shoe typically slides in a guidance mounted on the respective sash or frame member. The spring arrangement biasing the slide shoe is typically located in parallel with the respective sash or frame member. During opening and closing of the window the slide shoe slides in the guidance, urging a lifting arm connecting the slide shoe and the intermediate frame, or sash member, to and from the parallel position. The rotation of the lifting arm about an axis in the slide shoe requires means for rotatably connecting these two parts.

Lifting devices for roof windows making use of slide shoes are known and may be found for example in applicant’s EP2406448 B1 , wherein a lifting device comprising a biased slide shoe adapted to be slidable with respect to a member of an openable structure, a lifting arm having two ends, one end adapted to be pivotally connected with a member of the structure and the other end associated with said slide shoe, is described. Another ex-ample is found in applicant’s EP1520951 B1 , wherein a sliding device corn-prising a slide member having a slide shoe being adapted to engage a substantially U- shaped rail comprising a bottom wall, a side wall and a front wall is disclosed. What is common to the solutions disclosed in the above-mentioned documents is that slide shoes described therein are adapted to be connected to a further member, like a sash or a lifting arm, by means of a single eye. While serving the purpose of providing an axis around which a further member may be suitably rotatably connected to the slide shoe, the resulting connection is weak i.e. does not offer the stability and durability that is required by a lifting device for use in a roof window of the type described in the introduction; window sashes are progressively gaining in weight, as modern sashes include additional elements offering a greater range of functionalities, and better insulation properties requiring greater amount of materials being included in the construction of frames, panes and sashes. Furthermore, such means of connecting a slide shoe to a lifting arm in a roof window lifting device result in parts that need replacing with considerable frequency: A single rivet, or otherwise suitable part e.g. bolt, screw or pin, typically wears rapidly when submitted to the weight of the sash frame members, these also bearing the weight of the window pane. In addition, with frequent use of the lifting device, such a part is repeatedly subjected to forces that it is required to sustain. Wear on the rotational connecting means results in the transfer of said forces to other components of the system, which cumulatively results in inconsistent sliding of the slide shoe, and inefficient and imprecise opening and closing of the roof window. An additional problem with such an arrangement is that it does not simultaneously offer a solution for easily dismounting and replacing the used part.

Considering this, it is presently a challenge to provide a roof window lifting device with a sliding arrangement that can bear current load requirements while offering a durably smooth, precise and efficient use, while providing a solution for convenient rotational connection means replacement.

Summary of Invention

It is therefore the object of the invention to provide a roof window lifting device in which a slide shoe, or sledge system, is provided with durable rotational connection means to the lifting arm, thus providing smooth sliding, and thereby achieving precise and efficient operation of the roof window lifting device.

This is achieved with a roof window lifting device of the kind mentioned in the introduction, which is furthermore characterised in that the first end of the lifting arm is connected to the sledge system via an axle fixedly connected to said first end.

With the use of an axle, the forces generated by the operation of the lifting device during opening and closing of the roof window may be at least better sustained by the fact that the axle is supported at more than one point. Such forces will occur repeatedly with frequent operation of the roof window. The influence of the sledge system on the lifting arm and vice versa, may be more efficiently transferred via an axle. Thereby, precision, efficiency and durability may be greatly increased with respect to that of a single rivet or other suitable rotational connection means considered in the prior art. The term “fixedly” within the context of the present application should be interpreted in such manner that the lifting arm is connected to the axle and thus in turn to the sledge system at all time during operation, and may thus not inadvertently be released from the engagement.

In a presently preferred embodiment, the fixed connection is provided by positive engagement between the first end of the lifting arm and the axle, preferably by forming the first end as a closed portion. This provides for a mechanically simple, yet reliable connection.

In a preferred embodiment, the axle is mounted in the sledge system. By the inventive lifting device comprising a sledge that houses an axle, a better stability and increased sturdiness of the overall sledge system is enabled, and thereby a smoother operation of the sledge system may be obtained.

According to another embodiment, the axle comprises an at least partly essentially circular outer circumference and two end faces. By the essentially circular outer circumference of the axle of the lifting device, a smoother movement of the lifting arm around the rotational axis is obtained, thus possibly contributing to an overall more precise operation of the lifting device.

By“precise operation of the lifting device” it is meant that opposing stationary frame and movable sash elements align in an essentially parallel fashion, resulting in a tight juxtaposition of said opposing members in the closed window position. It is also meant that operation of the lifting device requires a predictable amount of force, as the tension spring bias is transferred with diminished hindrance to the lifting arm.

In addition, by presenting the outer circular surface of the axle directly in connection with the lifting arm, and in the absence of further coatings that could wear prematurely, a greater durability of the lifting device axle is possibly obtained. In another embodiment, an axle with a partly non-circular section is considered, particularly on the ends of the axle, with a width at least sufficient to receive the width of the lifting arm being circular. Such an embodiment offers the advantage of inserting the axle ends in reciprocal non- circular holes in the sledge wall parts, which reduces the chance of unintended rotation of the axle in the sledge wall parts occurring. According to another preferred embodiment, the axle is stationary in the sledge wall parts, and the lifting arm is free to rotate around the axle. The stationary nature of the axle in the sledge wall parts ensures greater overall sledge system stability. Furthermore, the lateral position of the axle in the sledge wall parts is more readily ensured if said axle is stationary in said wall parts. However, a further embodiment where the axle is stationary in the lifting arm and rotates in the sledge wall parts is also considered.

According to another embodiment wherein a runner is provided, the axle is adapted to further contact at least one cut-out in the runner wall portions. The cut out facilitates direct insertion of the axle in the sledge system during assembly. Furthermore, the cut out edge may extend circumferentially along the edge of the axle end face, further providing support and stabilization means to the axle. By stabilization it is meant that the cut-out edge will contribute to maintaining the axle in place by reducing the possibility for the axle being displaced laterally within the sledge wall parts.

Likewise, yet another embodiment wherein a runner is provided, the axle is adapted to further contact at least one bowl portion in the sledge or the runner. The axle being adapted to contact the bowl portion, the bowl portion provides further support to the axle and contributes to sustaining forces generated during operation of the lifting device and that are transferred between sledge system and the lifting arm via the axle.

In another preferred embodiment, the axle has at least one rifled end. This rifled end is suitable for being inserted into the at least one hole in said at least one sledge wall portion. By such an end, the axle may more easily be inserted into the hole, thus making assembly easier. Furthermore, such a rifled end contributes to the securing of the axle in the sledge system wall portion holes, thus rendering the axle more stationary. By rifled it is meant any arrangement present on the axle outer circumference that results in a non-smooth surface.

In a second aspect of the invention, a roof window incorporating such a lifting device is provided. Other presently preferred embodiments and advantages will be apparent from the appended description and drawings.

Brief Description of Drawings

In the following description embodiments of the invention will be described with reference to the schematic drawings, in which

Fig. 1 is a perspective view of a roof window, seen from the interior side and in an open position;

Fig. 2 is a perspective view of details of a roof window with a lifting device, in a first embodiment of the invention and corresponding to the open position of the roof window of Fig. 1 ;

Fig. 3 is an isometric view of the details of the roof window of Fig. 2, in a closed position of the window;

Fig. 4 is a partially exploded view of the details of Fig. 3;

Fig. 5 is an isometric view of the spring assembly shown in Fig. 3;

Fig. 6 is a partial isometric view, on a larger scale, of the spring assembly shown in Fig. 5;

Fig. 7 is a partial exploded isometric view of some elements of Fig. 6;

Figs 8a to 8e are isometric views of the elements of Fig. 7;

Fig. 9a is a partial isometric view, on a larger scale, of details shown in Fig. 3;

Fig. 9b is an exploded, partial perspective view of details of the lifting device in another embodiment of the invention;

Figs 10 and 11 are partial isometric views of details of the lifting device of the roof window in a second embodiment of the invention;

Figs 12a to 12h are schematic partial side views of an embodiment of the roof window of the invention, during coupling and uncoupling of the lifting device;

Figs 13a-13b, 14a-14b and 15a-15b are perspective views of details of the roof window in the second embodiment;

Fig. 16 shows a schematic perspective view of details of a roof window in a third embodiment of the invention; Fig. 17 shows a schematic side view of details of a roof window in a still further embodiment of the invention;

Figs 18a-18e are views corresponding to Figs 8a-8e, respectively, of details of the roof window in a third embodiment,

Figs 19a-19b are views corresponding to Figs 13a-13b, respectively, of details of the roof window in the third embodiment;

Fig. 20a is a view corresponding to Fig. 14a of details of the roof window in the third embodiment;

Fig. 20b is a partial perspective view of details of the roof window in the third embodiment; and

Figs 21 to 24 show partial or full, exploded, or sectional views of details of a roof window in yet another embodiment of the invention.

Description of Embodiments

Referring initially to Fig. 1 , the general configuration of a roof window which is top-hinged during normal operation and which pivots for cleaning is shown. Such a window is shown and described in further detail in Applicant’s above-mentioned European patent No. 0 733 146 B1 , the contents of which are hereby incorporated by reference. In Fig. 1 , a lifting device 10 is indicated, which, referring now also to Fig. 2 to 9, forms part of a first embodiment of the roof window according to the present invention.

The roof window comprises a primary frame in the form of a stationary frame 1 configured for installation in an inclined roof surface. At least one secondary frame is connected to the stationary frame 1 , in the embodiment shown a first secondary frame in the form of a sash 2 carrying a pane 4, and a second secondary frame in the form of an intermediate frame 3. The intermediate frame 3 is fastened to the stationary frame at a top mounting fitting 5, and the sash 2 is hinged at the top of the roof window, via the intermediate frame 3 to the stationary frame 1 , to render the roof window top-hung during normal operation. The sash 2 is also pivotally connected to the intermediate frame 3 in order to be able to rotate the sash 2 to provide access to the outside of the pane 4, for instance for cleaning purposes. To that end, the intermediate frame 3 is provided with a frame hinge part 6 of pivot hinge fitting. Although not shown in detail, it is clear to the skilled person that the sash 2 is provided with the counterpart sash hinge part of the pivot hinge fitting.

A lifting device 10 is composed of a spring arrangement 20 and a sledge system 30 which cooperate to assist in the opening of the window, that is, bringing the secondary frame or frames to an angled position relative to the primary frame. Here, from a closed position, the user operates the operating device of the window in the form of a handle 7 at the bottom member of the sash 2. The bias of the spring arrangement 20 of the lifting device 10 acts on a lifting arm 14 inserted between the stationary frame 1 and the intermediate frame 3. In turn, the lifting arm 14 exerts a moment on the intermediate frame 3 and hence to the sash relative to an axis through a top hinge pin 11. In combination with the force exerted by the user on the handle 7, transferred to a lifting moment, the moment resulting from the weight of the sash 2 with pane 4 is overcome. Closing the window from the open position entails the opposite movements of the sash 2 and relevant parts of the lifting device 10. A similar lifting device may be provided at each side of the roof window. Finally, the roof window is provided with a ventilation device 8 acting to allow passage of air also in the closed position of the window.

In further detail, the lifting arm 14 has a first end 12 rotatably connected with a sledge system 30, which in turn is slidably connected with the primary frame 1 in a sledge guidance 16, and a second end 13 rotatably connected with the at least one secondary frame 3, the lifting device 10 furthermore including a spring assembly 20 configured to be coupled to the sledge system 30. As the sledge system 30 is connected to the lifting arm 14, the spring assembly 20 is in turn configured to be connected to the first end 12 of the lifting arm 14 by means of a coupling mechanism, such that the spring assembly 20 is able to assume an uncoupled condition and a coupled condition relative to the sledge system 30. The coupling mechanism is the subject of Applicant’s co-pending patent application filed on the same day as the present invention. Operation of the presently preferred embodiments is described in further detail in connection with Figs 12a to 12h of Applicant’s co-pending international application filed on the same day as the present application and claiming the priority of DK PA 2017 70889 to which specific reference is hereby made.

Figs 5 and 6 show the general components of the spring assembly 20 of a roof window. Further details and advantages of the particular spring assembly 20 are the subject of Applicant’s co-pending patent application filed on the same day as the present application, and is shown for information purposes only in Figs 21 to 24. The present invention is however applicable to any kind of spring assembly. Thus, the general components of the spring assembly are: a tension rod 22 accommodating a buffer spring system 28 and a main spring system 29. The buffer spring system 28 acts as an auxiliary system to a main spring system 29. In order to adapt one and the same spring assembly to varying roof inclinations, an adjustment means is provided in the form of a movable adjustment plate 26 which is placed in one of several recesses 27a in a spring casing 27 accommodating the buffer spring system 28.

Referring now in particular to Figs 10-11 , 13a-13b and 15a, the coupling mechanism comprises a first coupling member 21 associated with the spring assembly 20 as is shown most clearly in Fig. 6.

The first coupling member 21 is adapted to cooperate with a second coupling member associated with the sledge system 30. In the first, second and third embodiment shown in Figs. 10-11 and 13a-15b, and Figs 18a-20b, the second coupling member comprises a sledge 31 forming part of the sledge system 30, and the sledge 31 includes receiving means configured to cooperate with the first coupling member 21 in the coupled condition.

In all of the embodiments shown, the first coupling member includes a hook element 21 to cooperate with the second coupling member including its receiving means formed in the sledge system 30 a sledge 31 of the sledge system 30 is comprised in a second coupling member of the coupling mechanism. The hook element 21 is configured to assume at least a non- engagement position and an engagement position, and the coupling mechanism furthermore comprises a coupling plate 25 arranged to assume at least a first position corresponding to the coupled condition and a second position corresponding to the uncoupled condition, the coupling plate 25 allowing the hook element 21 to assume said non-engagement position. Operation of the presently preferred embodiments will be described in further detail in connection with Figs 12a to 12h.

the receiving means of the second coupling member include at least one receiving recess 314 in the sledge 31 of the sledge system 30. The second coupling member could also take other shapes. One conceivable, alternative solution would be to utilise the axle 40 as receiving means. This alternative solution is shown as the fourth embodiment shown in Fig. 20.

Further details of the axle 40 will now be described in more detail with reference to Fig. 10 and Figs 15a-15b, 16 and 20b.

Fig.10 shows the axle of the invention mounted in the sledge system while connecting both the lifting arm 14 and the sledge system 30. The axle 40 comprises an at least partly essentially circular outer circumference, and two end faces. In a preferred embodiment, the axle has a circular outer circumference, thus being arranged to rotatably accommodate the lifting arm end 12 while being inserted into holes with circular circumference in the sledge 31 wall parts. The circular outer circumference enables rotatable attachment of the lifting arm. Thus, the portion of the axle presenting a circular outer circumference should be at least wide enough to accommodate the lifting arm end 12. The ends of the axle need in any case be arranged so as to be easily inserted into said holes in the sledge 30 wall parts, which shall be arranged to reciprocally accommodate said axle ends.

In the embodiment shown, said axle ends have a circular outer circumference, as do the holes in the sledge 30 wall parts, but these may have any other circumference shape, such as triangle, square, pentagonal etc., or an irregular shape. In any case, circumference shapes on axle and sledge wall parts should correspond to each other.

In principle the configuration of axle 40 in the sledge 31 or sledge system 32 may be carried out in any suitable manner as long as it fulfils the requirements due to the relatively large forces involved.

Turning now to the more detailed representation in Fig.17, the axle 40 is arranged so that a clearance is present between at least one end face of the axle 40 and the guidance 16. In the drawing shown, the clearance is achieved by the axle being shorter than the width of the runner 32, thus generating a clearance between the axle 40 and parts that may come into contact with the runner 32. In the image shown, the space generated is shared equally between the two axle end faces, thus generating clearance on both end of the axle 40. In any case, what is intended is that the axle 40 does not come into direct contact with the stationary frame 1 or with the guidance 16, if present.

The runner 32 houses the sledge 31 which accommodates the axle 40 through the sledge wall portion holes. Together, the runner and the sledge form the sledge system, which is connected to the spring assembly via a coupling mechanism as shown in Fig.12d. The bias of the spring assembly 20 of the lifting device 10 acts on a lifting arm 14 inserted between the stationary frame 1 and the intermediate frame 3 through the transfer of moment between the spring or springs in the spring assembly, and the sledge 31 , via the coupling mechanism, which urges the sledge system to slide, and transfer the moment to the lifting arm via the axle, as shown in Fig.12c. The axle of the invention is arranged to sustain and effectively transfer these relatively large forces. To this end, the axle is arranged to contact, if appropriate, a bowl portion in the sledge 31 or the runner 32, as shown in Fig.17. The bowl portion is arranged to receive the axle and thereby partially transfer the strain exerted by the lifting arm to the sledge system, thus supporting the axle. In the drawing shown, the bowl portion is arranged so as to provide sufficient space between the bowl portion and the sledge for the lifting arm end 12 to be accommodated in that space. In any case, it is known to the person skilled in the art that the axle of the invention is arranged to contact the bowl portion in a manner that is effective for supporting the axle.

Also in Fig.15a, the axle 40 is arranged so as to contact at least one cut-out 325, 326 in the wall portions 321 , 322 of the runner 32. The cut out edge may be arranged to extend circumferentially along the edge of the axle end face, thereby providing further support to the axle and contributing to maintaining the axle in place by reducing the possibility for the axle being displaced laterally within the wall portions of the sledge 31.

The arrangement shown in Fig.15a provides a robust and compact assembly with an axle that is arranged to sustain the forces transferred to the sledge system by the spring assembly and the lifting arm 14. To this end, the axle 40 is inserted into the sledge wall parts in such a manner that, in the mounted condition, the axle is made stationary under the forces commonly generated by the operation of the roof window lifting device. Fig.18 shows the axle 40 of the invention with one riffled end 401, which, when inserted into one of sledge 31 wall parts 315, 316, renders the axle stationary in the sledge system 30. By stationary it is meant that the riffled end 401 of the axle 40 will significantly reduce the possibility of the axle rotating and/or moving along the axis of the axle within the sledge wall part holes 315, 316, with normal use of the lifting device 10. The riffled end 401 provides a reduced contact surface between the axle 40 and the sledge wall part hole 315, 316 inner surface, thus enabling the forceful insertion of the axle into said hole, and concomitantly increasing friction between the two said parts. The drawings of FigslO and 11 show an axle 40 with a riffled end, but any arrangement that provides increased friction between the axle outer surface and the sledge wall part hole is also considered. Finally, the sledge 31 is provided with a second opening 318 and an incision 319 to make room for other parts of the lifting device 10.

In the third embodiment of the roof window shown in Figs. 19a-19b, the sledge 31 has been made longer relative to the sledge of the first and second embodiments. This provides the sledge 31 with a larger strength. As a consequence, the incision 319 is made longer.

At least one axle end 401 , 402 may comprise a location mark 404. Such a location mark requires a corresponding reference 403 on the sledge wall part or runner in such a manner that during mounting of the axle 40 in the sledge 31 , sufficient deformation of the material may be detected. A preferred way of achieving this is by mounting of the axle in the sledge wall part holes in such a way that the respective location mark on the axle end face and the said reference are substantially aligned.

The description of the sledge system 30 is given for information purposes only and is the subject of Applicant’s co-pending patent application filed on the same day as the present application. In order to control the frictional forces more precisely at the movement of the sledge system 30 in the sledge guidance 16, the sledge system 30 of the present invention comprises a runner 32, configured to accommodate the sledge 31 and being provided with at least one recess 324 opposite the respective receiving recess 314 of the sledge 31.

The runner 32 of the sledge system 30 comprises a runner 32 with at least two faces, a runner inner face and a runner outer face, and a sledge 31 , with at least two faces, a sledge inner face and a sledge outer face, the runner 32 comprising at least one wall portion 321 , 322, and being configured to accommodate said sledge 31 against its said runner inner face, and wherein said runner 32 is provided with at least one recess 324 opposite a respective receiving recess 314 in said sledge 31.

In the embodiment shown, the runner 32 is guided in the sledge guidance 16. Alternatively, the runner 32 could be guided directly in the primary frame 1.

Furthermore, the sledge 31 and/or said runner 32 further comprise means for reducing movement between said runner inner face and said sledge outer face. In the embodiment shown, the means for reducing movement between the runner inner face and the sledge outer face comprises a resilient upstanding portion 327 in the runner 32 and a respective opening 317 in said sledge 31 opposite said resilient upstanding portion 327.

Further means for reducing movement between the runner inner face and the sledge outer face comprises, in the embodiment shown, at least one flange on the at least one runner wall portion 321 , 322 arranged to abut the sledge 31.

As shown, at least part of one the runner wall portion 321 , 322 is thinner than the other wall portion 321 , 322, and a first journal section 321a, 322a is thinner than a second journal section 321 a, 322a.

The sledge 31 further comprises at least one narrowing 313 caused by at least one segment of the wall portion 311 , 312 being non-parallel with respect to the other wall portion 311 , 312. In this way, a clearance is generated between the sledge wall part and the frame member or guidance.

In the embodiment shown, the runner 32 further comprises a bowl portion 323 arranged to receive the axle 40, and the sledge 31 comprises a corresponding opening 317 opposite the bowl portion 323. The bowl portion 323 and the opening 317 are arranged so that the distance between the bowl portion 323 and the sledge first wall portion 311 is greater than the distance between the bowl portion 323 and the sledge second wall portion 312.

The runner 32 further comprises at least one cut-out 325, 326 in at least one wall portion 321 ,322 arranged to receive the axle 40.

The runner 32 here further comprises an edge portion 328 as a cut- out on at least one end.

In the embodiment shown, the runner 32 is formed of a plastic material such as POM which may also be provided with a coating of for instance Teflon® or other treatment having the function to act as a lubricant to reduce the friction.

The narrowing 313 on the runner 32 is made for reasons of space availability. By forming the runner slenderer in one side, it is possible to make 322a thicker, and tolerances are accommodated in the side where 322 is - in that way the axle 40 is guided such that the end 402 does not protrude to wear on the side of the guidance.

An edge portion 328 is provided as a cut-out in order to allow space for other parts of the assembly. A flange portion 329 scrapes the guidance to the sides of the guidance.

In general, the components of the lifting device are subjected to high loads, in particular in large roof windows and in low roof pitches. In such fields of application, the required lifting capacity of the lifting device may amount to close to 500 Nm. Loads of these magnitudes not only pose severe demands on the components but also require high performance of the spring assembly. In addition to the aspects covered by the present application, precautions have also been taken to mitigate adverse effects of the load in the top hinge pin 11 and the top bearing fitting 15. In order for the top hinge pin 11 to be safely lodged in the top bearing fitting 15 at all times, the top hinge pin 11 has been formed with a head and is furthermore secured against rotation. In order to transfer the load on the top hinge pin 11 exerted by the sash via the intermediate frame safely to the top bearing fitting 15, the top bearing fitting 15 is provided with protrusions (not shown in detail).

Above the invention has been described with reference to the sash and frame of a roof window, but it will be understood that it also applies to other frame structures, such as for example door frames.

List of reference numerals

1 primary frame (stationary frame)

2 first secondary frame (sash)

3 second secondary frame (intemediate frame)

4 pane

5 top mounting fitting

6 frame hinge part of pivot hinge fitting

7 handle

8 ventilation device

10 lifting device

11 hinge pin

12 first end of lifting arm

13 second end of lifting arm

14 lifting arm

15 top bearing fitting

16 sledge guidance

20 spring assembly

21 first coupling member / hook element

210 apex

211 aperture

212 base plate portion

213 flange portion

214 hook portion

215 rounded transition edge portion

216 inclined edge portion

217 top portion

217a groove in top portion

218 bottom edge portion

219 inclined edge portion

22 tension rod

221 rod portion

222 head portion

223 first inclined portion

224 second inclined portion

225 adjustment ring

23 angle element

231 aperture

231a enlarged aperture sections

232 upstanding leg

233 bottom leg

234 protruding flange 235 gap

end piece

241 aperture

242 upstanding wall

243 protrusion

244 protruding flange

244a rib portion

245 track

246 bent flange portions coupling plate

251 oblong aperture

252 base portion

253 bottom flange

254 cut-out

255 upstanding lug

256 friction-increasing portions adjustment plate

spring casing

27a recess for adjustment plate buffer spring system

281 outer spring

282 inner spring

283 spring plug

284 spring plug

main spring system

291 spring

292 spacer tube sledge system

second coupling member / sledge

310 bottom portion

311 first wall portion

312 second wall portion

313 narrowing

314 receiving recess

315 hole

316 hole

317 first opening

318 second opening

319 incision

runner

320 bottom portion

321 first wall portion

321a first journal section

322 second wall portion 322a second journal section

323 bowl portion

324 recess

325 cut-out

326 cut-out

327 resilient upstanding portion

328 edge portion

329 flange portion axle

401 rifled end

402 other end

403 markings

404 location mark friction brake device

51 friction brake element

52 first cone

53 second cone

54 spring plug