SYSTEM CONSISTING OF CATCH ELEMENTS AND FREIGHT CARRIERS

Abstract

A system includes a freight carrier, front catch element and rear catch element, the front edge of the base element of the freight carrier having front engagement elements, and the rear edge has rear engagement elements. The front catch element has front floor engagement devices to engage locking elements so movement of the front catch element in the floor surface plane and perpendicular thereto is prevented. The front catch element has front engagement devices to engage the front engagement elements. The rear catch element has rear floor engagement devices to engage locking elements in rails so movement of the rear catch element in the floor surface plane and perpendicularly thereto is prevented. The rear catch element has rear engagement devices to engage the rear engagement elements so movement of the rear catch element relative to the base element parallel to the plane of the supporting surface and perpendicular to the plane towards the supporting surface is prevented.

Claims

1. A system comprising: at least one freight carrier; at least one front catch element; and at least one rear catch element, wherein the freight carrier has a base element which has a supporting surface, which is configured to rest on a floor surface in an interior of an aircraft on a floor surface of a passenger cabin of the aircraft, and which has a front edge and a rear edge opposite the front edge, wherein the supporting surface is configured to move the freight carrier over the floor surface, wherein the base element has a main surface which is on the base element such that the main surface faces away from the supporting surface, and is configured such that freight elements can be accommodated thereon, wherein the front edge of the base element has front engagement elements, and wherein the rear edge has rear engagement elements, wherein the front catch element is configured to extend along the front edge of the base element and has front floor engagement devices which are configured to engage with locking elements in rails in the floor surface of the interior of the passenger cabin, such that a movement of the front catch element in a plane of the floor surface and perpendicular thereto is prevented, and wherein the front catch element has front engagement devices which are configured to engage with the front engagement elements such that a movement of the front catch element relative to the base element parallel to a plane of the supporting surface and perpendicular to the plane towards the supporting surface is prevented; wherein the rear catch element is configured to extend along the rear edge of the base element and has rear floor engagement devices which are configured to engage with locking elements in rails in the floor surface of the interior of the passenger cabin, such that a movement of the rear catch element in the plane of the floor surface and perpendicular thereto is prevented, and wherein the rear catch element has rear engagement devices which are configured to engage with the rear engagement elements such that a movement of the rear catch element relative to the base element parallel to the plane of the supporting surface and perpendicular to the plane towards the supporting surface is prevented.

2. The system according to claim 1, wherein the front engagement elements comprise bolts which are displaceable parallel to the plane of the supporting surface in relation to the base element and perpendicular to the front edge such that the bolts can take up a retracted and an extended position, wherein the bolts protrude further over the front edge in the extended position than in a retracted position, and wherein the front engagement devices comprise front openings which are configured to receive the bolts.

3. The system according to claim 2, wherein the bolts in the extended position protrude over the front edge to an extent such that they extend through the front catch element and through the front openings thereof such that they protrude over the front catch element when the front catch element extends along the front edge of the freight carrier.

4. The system according to claim 3, wherein the rear catch element has rear openings which are configured to receive the bolts when the rear catch element extends along the front catch element on a side of the front catch element which faces away from the freight carrier.

5. The system according to claim 2, wherein a free end of the bolts is conical.

6. The system according to claim 2, wherein the bolts are coupled to an actuating device which is configured to displace the bolts between the retracted and the extended position, wherein the actuating device has an actuating element which is movable between a first and a second position, and wherein the actuating device is configured such that, whenever the actuating element is in the first position, the bolts are in the retracted position, and that, whenever the actuating element is in the second position, the bolts are in the extended position.

7. The system according to claim 1, wherein, to move the freight carrier over the floor surface, wheels are movable in a direction transversely, and or perpendicularly, with respect to the supporting surface between a first and a second wheel position, and wherein the wheels do not protrude over the supporting surface in the first wheel position and protrude over the supporting surface in the second wheel position.

8. The system according to claim 7, wherein the bolts are coupled to an actuating device which is configured to displace the bolts between the retracted and the extended position, wherein the actuating device has an actuating element which is movable between a first and a second position, wherein the actuating device is configured such that, whenever the actuating element is in the first position, the bolts are in the retracted position, and that, whenever the actuating element is in the second position, the bolts are in the extended position, wherein the actuating device is furthermore coupled to the wheels such that it moves the wheels between the first and the second wheel position, and wherein the actuating device is configured such that, whenever the actuating element is in the first position, the wheels are in the second wheel position, and that, whenever the actuating element is in the second position, the wheels are in the first wheel position.

9. The system according to claim 1, wherein the rear engagement elements comprise two rear receiving openings extending perpendicular to the rear edge and parallel to the plane of the supporting surface, and wherein the rear engagement device has rear protrusions which are configured to be received in the receiving openings.

10. The system according to claim 9, wherein the rear receiving openings are dimensioned to receive forks of a forklift truck.

11. The system according to claim 1, wherein the front and rear floor engagement devices are configured to engage with locking elements which are arranged in at least two rails extending parallel to one another in the floor surface.

12. The system according to claim 11, wherein the locking elements have locking bolts which protrude over the floor surface, and wherein the front and the rear locking element have bores for receiving the locking bolts.

13. The system according to claim 1, wherein the front and the rear floor engagement device are configured such that the front and the rear catch element are fastenable to the rails in the floor surface of the interior of the passenger cabin, in different positions transversely with respect thereto.

14. The system according to claim 1, wherein the front catch element has a multiplicity of bores along a direction which runs parallel to the front edge of the base element when the front engagement elements are in engagement with the front engagement devices, and therefore locking bolts in the rails can engage with the bores in the front catch element, and wherein the rear catch element has a multiplicity of bores along a direction which runs parallel to the rear edge of the base element when the rear engagement elements in engagement with the rear engagement devices, and therefore locking bolts in the rails can engage with the bores in the rear catch element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The disclosure herein is explained below with reference to a drawing in which only preferred example embodiments are reproduced, wherein:

[0042] FIG. 1 shows a perspective view of an aircraft, in the interior of which, and in particular in the passenger cabin of which, the example embodiments of the system according to the disclosure herein consisting of freight carriers and catch elements can be accommodated;

[0043] FIG. 2 shows a lateral sectional illustration of a freight carrier of an example embodiment of a system according to the disclosure herein;

[0044] FIG. 3 shows a top view of the freight carrier from FIG. 2, wherein bolts are in a retracted position;

[0045] FIG. 4 shows a top view of the freight carrier in FIG. 2, wherein the bolts are in an extended position;

[0046] FIG. 5 shows a perspective illustration of a freight carrier and of a rear catch element according to an example embodiment of the disclosure herein,

[0047] FIG. 6 shows a detail from FIG. 5;

[0048] FIG. 7 shows a perspective illustration of the freight carrier and of a front catch element according to the example embodiment shown in FIGS. 5 and 6;

[0049] FIG. 8 shows a detail from FIG. 7;

[0050] FIG. 9 shows a sectional view from the rear of the freight carrier and the rear catch element according to FIG. 5;

[0051] FIGS. 10a and 10b show details of the freight carrier of the example embodiment from FIGS. 5 to 9;

[0052] FIG. 11 shows a lateral sectional illustration of two adjacent freight carriers and of a front and a rear catch element according to an example embodiment of the disclosure herein, wherein bolts of the one freight carrier are partially accommodated in the front catch element; and

[0053] FIG. 12 shows a lateral sectional illustration similar to FIG. 11, wherein the bolts of the one freight carrier are completely accommodated in the front and the rear catch element between two freight carriers.

DETAILED DESCRIPTION

[0054] FIG. 1 shows an aircraft which, in a conventional manner, has a passenger cabin 1 and a hold 3, wherein the example embodiments described below of freight systems according to the disclosure herein can be accommodated both in the passenger cabin 1 and in the hold 3. However, the use is particularly preferred in which the example embodiments of systems according to the disclosure herein are accommodated in the passenger cabin 1, wherein the cabin doors 5 are used in this case in order to introduce the freight carriers 7 into the passenger cabin 1.

[0055] The example embodiments of the systems according to the disclosure herein comprise at least one freight carrier 7 and at least one front catch element and at least one rear catch element. Example embodiments of these elements are described below with reference to the figures.

[0056] FIGS. 2 through 4 reveal a lateral sectional view and top views of an example embodiment of a freight carrier 7 of a system according to the disclosure herein, wherein the example embodiment of a freight carrier 7 has a base element 9, wherein the base element has a supporting surface 11 which is provided to rest on the floor surface 13 of the passenger cabin 1 whenever the freight carrier 7 is arranged at the location provided for it in the passenger cabin 1 of the aircraft. Furthermore, the base element 9 of the freight carrier 7 has a main surface 15 which is opposite the supporting surface 11 and is provided for freight elements, for example luggage, but also other freight, to be able to be accommodated thereon. In this case, the freight carrier 7, as shown in FIGS. 2 through 4, can have a frame 17 and optionally also fixed walls which surround a receiving space. However, it is just as readily possible for the freight carrier 7 to have only the base element 9, on which the freight elements can then be arranged, and not to have a frame and/or wall. A freight carrier 7 according to the disclosure herein therefore does not necessarily also comprise a wall surrounding a receiving space.

[0057] As can furthermore be gathered from FIGS. 2 through 4, the example embodiment of a freight carrier 7 that is shown in these figures has structure in order to move the freight carrier 7 over the floor surface of the interior, or of the passenger cabin 1, of the aircraft, wherein the structure is provided in the supporting surface 11 and, in the present example embodiment, are formed by wheels 19, wherein the wheels can be moved between a first wheel position, in which the wheels spring back behind the supporting surface 11 and therefore do not protrude at all beyond the latter here, and a second wheel position, which is shown in FIG. 2.

[0058] In addition, the base element 9 of the freight carrier 7 has a front edge 21 and a rear edge 23 opposite the latter, wherein, in the example embodiment described here, the base element 9 is rectangular, and therefore the front edge 21 and the rear edge 23 run parallel to each other.

[0059] In the region of the front edge 21 of the freight carrier 7, bolts 25 are provided which form front engagement elements and, in the example embodiment of a freight carrier 7 of a system according to the disclosure herein that is illustrated in FIGS. 2 to 4, can be moved between a retracted position (see FIG. 3) and an extended position (see FIGS. 2 and 4). For this purpose, the freight carrier 7 has an actuating device which comprises a plurality of actuating rods 27 which run parallel to one another and extend between the front edge 21 and the rear edge 23. In addition, in this example embodiment, the actuating device has an actuating element in the form of an actuating arm 29 which is pivotable about a horizontal pivot axis and which can be moved between a first position (see FIGS. 2 and 4) and a second position (see FIG. 3), wherein, in the example embodiment described here, the actuating arm 29 is held pivotably on the base element 9. During a pivoting movement of the actuating arm 29 from the first position into the second position, the actuating rods 27 are displaced inside the base element 9, wherein this movement runs in the plane of the supporting surface 11. Since the bolts 25, the free ends of which, as illustrated in FIGS. 2 through 4, are conical, are provided at the free ends of the actuating rods 27, the bolts, during the movement of the actuating arm from the first position thereof into the second position thereof, are brought out of the retracted position, in which they protrude only to a slight extent, if at all, over the front edge 21, into the extended position, in which, in comparison to the retracted position, they protrude to a relatively large extent over the front edge 21.

[0060] In addition, the actuating rods 27 are provided with first engagement surfaces 31 which run at an inclination to the supporting surface 11 and which engage with second engagement surfaces 35, which are provided on holders 33 for the wheels 19, and therefore, as is apparent from FIG. 2, a displacement movement of the actuating rods 27 leads to a movement of the holders 33 perpendicular to the supporting surface 11. Therefore, during the movement of the actuating rod 27, the wheels 19 are moved between the first wheel position and the second wheel position. In particular, the configuration of the actuating device with the actuating rods 27 and the first and second engagement surfaces 31, 35 and also the actuating arm 29 is configured in such a manner that, whenever the actuating arm 29 is in the first position, in which the bolts 25 are in the retracted position, the wheels 19 are in the second wheel position, in which they protrude over the supporting surface 11. If the actuating arm 29 is brought into the second position, the bolts 25 are moved into the extended position while, at the same time, the wheels 19 are brought into the first wheel position, in which they no longer protrude over the supporting surface 11, and therefore the freight carrier 7 or the base element 9 then rests on the floor surface 13.

[0061] The actuating device is therefore configured in such a manner that the front engagement elements in the form of the bolts 25 are moved parallel to the wheels 19, wherein, for this purpose, only one actuating element, or optionally a plurality of common actuating elements, here in the form of the actuating arm 29, have to be moved.

[0062] FIGS. 5 to 10 show freight carriers 7 which are constructed entirely similarly to those from FIGS. 2 to 4 and differ therefrom only in that a frame 17 is not provided above the main surface 15 and in that here, instead of only one actuating arm, two actuating arms 29′ are provided which have to be pivoted about vertical axes in order to move the actuating rods 27 which, in turn, are coupled to the bolts 25 and to the holders 33 for the wheels 19.

[0063] As is shown in particular in FIGS. 10a and 10b, actuating arms 29′ are attached to the rear edge 23 of the base element 9 of the example embodiment so as to be pivotable about vertical axes 29″, and therefore the actuating arms 29′ can be pivoted between the positions shown in FIG. 10a and in FIG. 10b. The actuating arms 29′ are coupled with the aid of pins 36 to the actuating rods 27 which firstly move the bolts 25 between the retracted and the extended position and secondly move the wheels 19 between the first and the second wheel position. If the actuating arms 29′ are in the outwardly pivoted, first position shown in FIG. 10a, the bolts 25 are in the retracted position and the wheels 19 are in the second wheel position, in which they protrude over the supporting surface 11 of the base element 9. If, however, the actuating arms 29′ are pivoted into the position shown in FIGS. 5 and 10b, the actuating rods 27 are displaced by the coupling via the pins 36 in such a manner that the bolts 25 are brought into the extended position and the wheels 19 are displaced into the first wheel position, in which they do not protrude over the supporting surface 11 of the base element 9.

[0064] In order to fix the freight carriers 7 with their supporting surfaces 11 to the floor surface 13 of the interior, and in particular of the passenger cabin 1, of the aircraft, the example embodiments of systems according to the disclosure herein have a front catch element 37 (see FIGS. 7 and 8) and a rear catch element 39 (see FIGS. 5 and 6), wherein the rear catch element 39 has rear engagement devices in the form of rear protrusions 41 which are configured to extend into rear receiving openings 43 forming rear engagement elements. The rear protrusions 41 and the rear receiving openings 43 are dimensioned in such a manner that, whenever the rear protrusions 41 extend into the rear receiving openings 43 and therefore engage with one another, a movement of the rear catch element 39 relative to the base element 9 parallel to the plane of the supporting surface 11 and perpendicularly to the plane towards the supporting surface 11 is prevented. If the rear protrusions 41 engage with the receiving openings 43, the rear catch element 39 can no longer be displaced parallel to the plane of the supporting surface 11 in relation to the base element 9 because the distance between the rear protrusions 41 corresponds to the width of the receiving openings 43. In addition, the rear protrusions 41 rest on the base of the receiving openings 43, and therefore the rear catch element 39 can no longer be moved towards the supporting surface 11. If both the base element 9 and the rear catch element 39 rest on the floor surface 13 of the interior and the rear protrusions 41 extend into the rear receiving openings 43, the previously described configuration of rear protrusions 41 and rear receiving openings 43 and therefore the rear engagement elements and engagement devices means that the base element 9, and therefore the freight carrier 7, cannot be moved away from the floor surface 13, but rather is held fixed thereon.

[0065] As is revealed in FIGS. 5 and 6 and also 9, the rear catch elements 39 are fastened to rails 45, wherein the rails 45 extend parallel to one another in the floor surface 13 of the interior, and in particular in the passenger cabin 1 of the aircraft. These rails 45 can be provided in particular to hold rows of seats on the floor surface 13 and to transmit the loads resulting therefrom into the structure of the aircraft. As can be seen in particular from FIG. 9, locking elements in the form of locking bolts 47 can be arranged in the rails 45, which locking elements are held along the longitudinal direction of the rails 45 so as to be non-displaceable therein and also cannot move out of the rails 45 perpendicular to the plane of the floor surface 13.

[0066] These locking bolts 47 are received in bores 49, forming floor engagement devices, in the rear catch element 39 and secured in relation to the rear catch element 39 by a nut, not illustrated, and therefore the catch element cannot move away from the floor surface 13.

[0067] As can be gathered from FIGS. 5 and 6, the rear catch element 39 according to the disclosure herein has a multiplicity of bores 49 which, when the rear catch element 39 is arranged on the rear edge 23 of the base element 9, are arranged along the rear edge 23. This makes it possible for the rear catch element 39 to be able to be fastened to the rails 45 in different positions relative thereto, wherein these positions are offset in the transverse direction with respect to the rails 45. In addition, the multiplicity of bores 49 in the rear catch element 39 make it possible for the latter to be able to be fastened to rails 45 at different distances from one another.

[0068] It can furthermore be seen from FIGS. 7 and 8 that the freight carrier 7 shown in these figures is fastened at its front edge 21 to the rails 45 in the floor surface 13 with the aid of a front catch element 37. The front catch element 37 extends along the front edge 21 and, similarly to the rear catch element 39, has front protrusions 51 which extend into front receiving openings 53 in the front edge 21 of the base element 9. In contrast to the rear receiving openings 43 and the rear protrusions 41 which enter into engagement at the rear edge 23 of the base element, it is the case, however, at the front edge 21 that, as FIG. 8 in particular reveals, the front protrusions 51 do not rest on the base 55 of the front receiving openings 53 when both the base element 9 and the front catch element 37 rest on the floor surface 13; instead, in this case, there is a gap between the lower side of the front protrusions 51 and the base 55 such that the base element 9 can already be brought into engagement with the front protrusions 51 when it is spaced apart from the floor surface 13 because of the wheels 19 still being extended. However, the front protrusions 51 are spaced apart from one another in such a manner that a displacement of the base element 9 parallel to the direction of extent of the front catch element 37 and therefore parallel to the supporting surface is not possible.

[0069] Furthermore, it can be seen from FIGS. 7 and 8 that the bolts 25 are provided on the front edge 21 of the base element, which bolts, whenever the actuating elements 29′ have been brought into the position shown in FIGS. 5 and 10a, extend beyond the front edge 21 and then engage with front openings 57 which are provided on the front catch element 37.

[0070] As can furthermore be seen from FIG. 8, the front catch element 37 also has bores 49 which form floor engagement devices and in which locking bolts 47 which extend upwards away from the rails 45 can be accommodated, wherein the locking bolts 47 are then secured, for example, by nuts such that the front catch element 37 can no longer be lifted off from the floor surface 13 or the rails 45. In addition, it can also be gathered from FIG. 8 that a multiplicity of bores 49 are provided along the front catch element 37, as also in the case of the rear catch element 39, and therefore the front catch element 37 can also be arranged in different positions relative to the rails 45. In addition, it is thereby possible for the front catch element 37 to also be able to be used at different distances of the rails 45.

[0071] If the front catch element 37 is fastened to the rails 45 by the locking bolts 47 and further nuts such that it can no longer be lifted off from the rails 45, and if furthermore the bolts 25 engage with the front openings 57, a movement of the front catch element 37 relative to the base element 9 parallel to the plane of the supporting surface 11 and perpendicular to the plane towards the supporting surface 11 is prevented. This is because, by the engagement of the bolts 25 with the front openings 57, it is specifically prevented that the front catch element 37 can be displaced along the front edge 21 both in the vertical and in the horizontal direction. This in turn leads to the fact that, when the bolts 25 engage with the front openings 57, forces which lift off the base element 9 and therefore the freight carrier 7 from the floor surface 13 are introduced via the rails 45 into the structure of the aircraft.

[0072] FIGS. 11 and 12 show lateral sectional illustrations of a further example embodiment of a system consisting of freight carriers 7 with base elements 9 and front and rear catch elements 37, 39. As already described in conjunction with the example embodiment from FIGS. 2 to 4, the freight carriers 7 also have base elements 9 here in which actuating rods 27 are guided displaceably, such that they can be displaced with the aid of an actuating arm which is not shown in FIGS. 11 and 12 and which can take up a first position and a second position, wherein, in the first position, a bolt 25 connected to the actuating rod 27 and having a conical end is in a retracted position (see FIG. 11), in which it protrudes only to a small extent over the front edge 21 of the base element 9. If the actuating arm 29 is brought into the second position, the bolt 25 protrudes, because of the movement of the actuating rod 27, to a greater extent over the front edge 21 of the base element 9 (see FIG. 12).

[0073] Also in this example embodiment, the actuating rod 27 in the base element 9 of the freight carriers 7 is provided with a first engagement surface 31 which runs in an inclined manner and engages with a second engagement surface 35 on the holder 33, on which, in turn, the wheels 19 are held. The wheels 19 can also be moved here between a first wheel position and a second wheel position, wherein, in the first wheel position (see FIG. 12), the wheels 19 do not protrude over the supporting surface 11 of the base elements 9. However, in the second wheel position (see FIG. 11), the wheels 19 protrude over the supporting surface 11 such that the freight carriers can be moved in a simple manner over a floor surface 13. The actuating rods 27 and the holders 33 are also coupled here in such a manner that, whenever the actuating arm 29, not illustrated, is in the first position, the bolts 25 are in the retracted position and the wheels 19 are in the second (extended) wheel position, while, whenever the actuating arm 29 is in the second position, the bolts 25 are in the extended position and the wheels 19 are in the first (retracted) wheel position.

[0074] As can furthermore be gathered from FIGS. 11 and 12, a front catch element 37 and a rear catch element 39 can be arranged between two freight carriers 7, which are arranged on the floor surface 13 of the interior of the aircraft, and in particular of the passenger cabin thereof, wherein the front catch element 37 extends along the front edge 21 of the one freight carrier 7, while the rear catch element 39 runs along the rear edge 23 of the second freight carrier 7, which is arranged in front of the one freight carrier 7.

[0075] The catch elements 37, 39 are also fixedly connected here to rails in the floor surface 13 of the interior with the aid of locking bolts 47, which extend through bores 49, forming floor engagement devices, in the catch elements 37, 39 and are secured by nuts, wherein these rails are also directly connected here to the structure of the aircraft. Also in this example embodiment, in the catch element 37, 39, a multiplicity of bores 49 are provided along the running direction and the catch elements 37, 39 and therefore along the rear edge 23 and the front edge 21, and therefore the catch elements 37, 39 can be attached in different positions relative to the rails.

[0076] Furthermore, it can be gathered from FIGS. 11 and 12 that the front catch elements 37 have front openings 57 in which the bolts 25 can be accommodated. The front openings 57 are designed here as through openings such that the bolts 25, when they are in the extended position (see FIG. 12), can extend through them and are additionally received by rear openings 59 in the rear catch element 39 arranged directly adjacent to the front catch element 37.

[0077] As a result, the bolts 25 and therefore the front engagement elements provided on the base element 9 of the one freight carrier 7 pass into engagement both with the front catch element 37 and with the rear catch element 39 arranged adjacent thereto. As a result, the front edge 21 of the freight carrier 7, which is illustrated on the left in FIGS. 11 and 12, is therefore secured by two catch elements 37, 39, and therefore the edge is held redundantly on the structure of the aircraft.

[0078] With the previously described example embodiments of a system consisting of freight carriers 7 and front and rear catch elements 37, 39, it is possible to hold the freight carriers 7 in a simple manner on the floor surface 13 of the interior, and in particular of the passenger cabin 1 of an aircraft, in such a manner that, firstly, the forces acting on the freight carriers are introduced into the structure of the aircraft and, secondly, the outlay on the fastening is comparatively small. Furthermore, with just a small outlay, a passenger cabin 1, in which rows of seats are fastened to rails 45 in the floor surface, can be set up for use with the system according to the disclosure herein. All that is required for this purpose is to remove the rows of seats in the region in which the freight carriers 7 are intended to be accommodated.

[0079] While at least one example embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

LIST OF REFERENCE SIGNS

[0080] 1 Passenger cabin [0081] 3 Hold [0082] 5 Cabin door [0083] 7 Freight carrier [0084] 9 Base element [0085] 11 Supporting surface [0086] 13 Floor surface [0087] 15 Main surface [0088] 17 Frame [0089] 19 Wheels [0090] 21 Front edge [0091] 23 Rear edge [0092] 25 Bolt [0093] 27 Actuating rod [0094] 29, 29′ Actuating arm [0095] 29″ Vertical axis [0096] 31 First engagement surface [0097] 33 Holder [0098] 35 Second engagement surface [0099] 36 Pin [0100] 37 Front catch element [0101] 39 Rear catch element [0102] 41 Rear protrusions [0103] 43 Rear receiving openings [0104] 45 Rail [0105] 47 Locking bolts [0106] 49 Bore [0107] 5 [0108] 51 Front protrusion [0109] 53 Front receiving opening [0110] 55 Base [0111] 57 Front opening [0112] 59 Rear openings