阅读说明：本技术 一种防剧烈晃动的无人机用降落结构 (Prevent violently rocking unmanned aerial vehicle with descending structure ) 是由 余永光 于 2019-12-09 设计创作，主要内容包括：本发明公开的一种防剧烈晃动的无人机用降落结构,包括无人机本体,所述无人机本体的底端固定连接有第一连接板,所述第一连接板的下方设有底板,所述底板与第一连接板通过第一缓冲机构连接,所述底板的顶端两侧对称开设有方形孔,所述方形孔内设有支撑杆,所述支撑杆与方形孔通过转轴活动连接,所述底板的顶端两侧对称设有缓冲箱,所述缓冲箱为底端开口的空腔结构,所述支撑杆的顶端延伸至缓冲箱内。本发明所述的一种防剧烈晃动的无人机用降落结构,当无人机本体垂直甚至倾斜降落时,都可以减少无人机本体与地面接触时的瞬间冲击力对无人机本体本身造成的影响,进而减少无人机内部电子零件损伤的可能,增加了无人机的使用寿命。(The invention discloses a violent-shaking-prevention descending structure for an unmanned aerial vehicle, which comprises an unmanned aerial vehicle body, wherein a first connecting plate is fixedly connected to the bottom end of the unmanned aerial vehicle body, a bottom plate is arranged below the first connecting plate, the bottom plate is connected with the first connecting plate through a first buffer mechanism, square holes are symmetrically formed in two sides of the top end of the bottom plate, supporting rods are arranged in the square holes, the supporting rods are movably connected with the square holes through rotating shafts, buffer boxes are symmetrically arranged on two sides of the top end of the bottom plate, each buffer box is of a cavity structure with an opening in the bottom end, and the top ends of the supporting rods extend into the corresponding buffer box. According to the anti-violent-shaking landing structure for the unmanned aerial vehicle, when the unmanned aerial vehicle body vertically or even obliquely lands, the influence of the instantaneous impact force generated when the unmanned aerial vehicle body is in contact with the ground on the unmanned aerial vehicle body can be reduced, the possibility of damage to electronic parts in the unmanned aerial vehicle is further reduced, and the service life of the unmanned aerial vehicle is prolonged.)

1. The utility model provides a prevent acutely rocking unmanned aerial vehicle with descending structure which characterized in that: comprises an unmanned aerial vehicle body (1), wherein a first connecting plate (2) is fixedly connected with the bottom end of the unmanned aerial vehicle body (1), a bottom plate (3) is arranged below the first connecting plate (2), the bottom plate (3) is connected with the first connecting plate (2) through a first buffering mechanism, square holes (4) are symmetrically formed in the top end of the bottom plate (3), supporting rods (6) are arranged in the square holes (4), the supporting rods (6) are movably connected with the square holes (4) through rotating shafts (7), buffering boxes (5) are symmetrically arranged on the top end of the bottom plate (3), the buffering boxes (5) are of cavity structures with open bottom ends, the top ends of the supporting rods (6) extend into the buffering boxes (5), the supporting rods (6) are connected with the buffering boxes (5) through supporting mechanisms, limiting rods (23) located on two sides of the supporting rods (6) are arranged in the square holes (4), the bottom of bracing piece (6) and first fixed plate (8) fixed connection who is located bottom plate (3) below, the below of first fixed plate (8) is equipped with backup pad (9), backup pad (9) are connected through second buffer gear with first fixed plate (8), the both ends symmetry of backup pad (9) is equipped with first arc backup pad (10), two one side that backup pad (9) kept away from mutually all is equipped with second connecting plate (11), one side that backup pad (9) were kept away from in second connecting plate (11) is equipped with second arc backup pad (12), second arc backup pad (12) are connected through the moving mechanism with second connecting plate (11).

2. The descent structure of an unmanned aerial vehicle against violent shaking of the claim 1, wherein: the supporting mechanism comprises two pressing plates (13) arranged in the buffer box (5), the two pressing plates (13) are located on two sides of the supporting rod (6) respectively, the pressing plates (13) are in contact with the supporting rod (6), a moving plate (14) is arranged on one side, away from the pressing plates (13), of the moving plate (14) and the pressing plates (13) and connected through a plurality of telescopic rods (15), a first spring (16) is sleeved outside the telescopic rods (15), and the moving plate (14) is connected with the buffer box (5) through a driving mechanism.

3. The descent structure of an unmanned aerial vehicle against violent shaking of the claim 2, wherein: actuating mechanism sets up first through-hole (17) in baffle-box (5) both sides including the symmetry, ring channel (18) have been seted up to the inner wall of first through-hole (17), be equipped with first screw thread rotation axis (19) in first through-hole (17), be equipped with first solid fixed ring (20) in ring channel (18), just the inner wall and first screw thread rotation axis (19) fixed connection of first solid fixed ring (20), the one end of first screw thread rotation axis (19) and rotary disk (21) fixed connection who is located baffle-box (5) outer wall, movable plate (14) are run through to the other end of first screw thread rotation axis (19), just the one end of first screw thread rotation axis (19) and be located movable plate (22) between baffle (14) and the pressure board (13) and be connected.

4. The descent structure of an unmanned aerial vehicle against violent shaking of the claim 3, wherein: the first threaded rotating shaft (19) is connected with the moving plate (14) in a threaded mode, and the side wall of the moving plate (14) is in contact with the inner wall of the buffer box (5).

5. The descent structure of an unmanned aerial vehicle against violent shaking of the claim 1, wherein: first buffer gear is including offering damping groove (24) in first connecting plate (2) bottom, be equipped with connecting block (25) in damping groove (24), the top of connecting block (25) is connected through a plurality of second springs (26) with the top inner wall of damping groove (24), the bottom of connecting block (25) and the top fixed connection of bottom plate (3).

6. The descent structure of an unmanned aerial vehicle against violent shaking of the claim 5, wherein: spacing groove (27) have been seted up to the both sides inner wall symmetry of shock attenuation groove (24), be equipped with stopper (28) in spacing groove (27), stopper (28) and connecting block (25) fixed connection.

7. The descent structure of an unmanned aerial vehicle against violent shaking of the claim 1, wherein: the movable mechanism is including setting up in second fixed plate (30) on second connecting plate (11) top, second fixed plate (30) and second connecting plate (11) fixed connection, just second fixed plate (30) slope sets up, second fixed plate (30) are connected through a plurality of elasticity posts (31) with second arc backup pad (12), the outside cover of elasticity post (31) is equipped with third spring (32), top one side of second arc backup pad (12) and top one side of second connecting plate (11) are through a plurality of hinges (29) swing joint.

8. The descent structure of an unmanned aerial vehicle against violent shaking of the claim 1, wherein: second buffer gear includes a plurality of second through-holes (33) of seting up on first fixed plate (8) top, be equipped with second screw thread rotation axis (34) in second through-hole (33), the bottom and backup pad (9) fixed connection of second screw thread rotation axis (34), the outside cover of second screw thread rotation axis (34) is equipped with the solid fixed ring of second (36) that are located first fixed plate (8) top, the outside cover of second screw thread rotation axis (34) is equipped with fourth spring (35) that are located between first fixed plate (8) and backup pad (9).

9. The descent structure of an unmanned aerial vehicle against violent shaking of the claim 8, wherein: and the inner wall of the second fixing ring (36) is provided with threads matched with the second threaded rotating shaft (34).

Technical Field

The invention relates to the field of unmanned aerial vehicles, in particular to a violent-shaking-preventing landing structure for an unmanned aerial vehicle.

Background

The unmanned plane is called unmanned plane for short, and is called UAV in English, and is an unmanned plane operated by radio remote control equipment and a self-contained program control device. From a technical point of view, the definition can be divided into: unmanned fixed wing aircraft, unmanned vertical take-off and landing aircraft, unmanned airship, unmanned helicopter, unmanned multi-rotor aircraft, unmanned paravane aircraft, and the like. Unmanned aerial vehicles can be classified into military and civil applications according to the application field. For military use, unmanned aerial vehicles divide into reconnaissance aircraft and target drone. In the civil aspect, the unmanned aerial vehicle + industry application is really just needed for the unmanned aerial vehicle, and is currently applied to the fields of aerial photography, agriculture, plant protection, self-photography, express transportation, disaster relief, wild animal observation, infectious disease monitoring, surveying and mapping, news reporting, electric power inspection, disaster relief, movie and television shooting and the like, so that the application of the unmanned aerial vehicle is greatly expanded, and developed countries are also actively expanding the industry application and developing the unmanned aerial vehicle technology. And unmanned aerial vehicle is when descending, probably descends perpendicularly, leads to the slope to descend because of other reasons even, and the impact force in the twinkling of an eye when unmanned aerial vehicle and ground contact can cause whole unmanned aerial vehicle to rock, and then probably causes the damage to the inside electronic part of unmanned aerial vehicle, has reduced unmanned aerial vehicle's life.

Disclosure of Invention

The invention mainly aims to provide a falling structure for an unmanned aerial vehicle, which can prevent violent shaking and effectively solve the problems in the background technology.

In order to achieve the purpose, the invention adopts the technical scheme that:

a falling structure for preventing violent shaking for an unmanned aerial vehicle comprises an unmanned aerial vehicle body, wherein a first connecting plate is fixedly connected to the bottom end of the unmanned aerial vehicle body, a bottom plate is arranged below the first connecting plate, the bottom plate is connected with the first connecting plate through a first buffer mechanism, square holes are symmetrically formed in the top end of the bottom plate, supporting rods are arranged in the square holes and are movably connected with the square holes through rotating shafts, buffer boxes are symmetrically arranged on the top end of the bottom plate, the buffer boxes are of a cavity structure with an opening at the bottom end, the top ends of the supporting rods extend into the buffer boxes, the supporting rods are connected with the buffer boxes through supporting mechanisms, limiting rods located on two sides of the supporting rods are arranged in the square holes, the bottom ends of the supporting rods are fixedly connected with a first fixing plate located below the bottom plate, supporting plates are arranged below the, the backup pad passes through the second buffer gear with first fixed plate and is connected, the both ends symmetry of backup pad is equipped with first arc backup pad, two one side that the backup pad was kept away from mutually all is equipped with the second connecting plate, one side that the backup pad was kept away from to the second connecting plate is equipped with second arc backup pad, second arc backup pad passes through the swing mechanism with the second connecting plate and is connected.

Preferably, the supporting mechanism comprises two pressing plates arranged in the buffer box, the two pressing plates are respectively located on two sides of the supporting rod and are in contact with the supporting rod, a moving plate is arranged on one side, away from the two pressing plates, of the pressing plates and is connected with the pressing plates through a plurality of telescopic rods, a first spring is sleeved outside the telescopic rods, and the moving plate is connected with the buffer box through a driving mechanism.

Preferably, actuating mechanism sets up the first through-hole in the baffle-box both sides including the symmetry, the ring channel has been seted up to the inner wall of first through-hole, be equipped with first screw thread rotation axis in the first through-hole, be equipped with first solid fixed ring in the ring channel, just first solid fixed ring's inner wall and first screw thread rotation axis fixed connection, the one end of first screw thread rotation axis and the rotary disk fixed connection who is located the baffle-box outer wall, the other end of first screw thread rotation axis runs through the movable plate, just the one end of first screw thread rotation axis and the limiting plate connection who is located the movable plate and presses between the platen.

Preferably, the first threaded rotating shaft is connected with the moving plate in a threaded manner, and the side wall of the moving plate is in contact with the inner wall of the buffer box.

Preferably, first buffer gear is including seting up the shock attenuation groove in first connecting plate bottom, be equipped with the connecting block in the shock attenuation groove, the top of connecting block and the top inner wall of shock attenuation groove pass through a plurality of second spring coupling, the bottom of connecting block and the top fixed connection of bottom plate.

Preferably, the inner walls of the two sides of the damping groove are symmetrically provided with limiting grooves, limiting blocks are arranged in the limiting grooves, and the limiting blocks are fixedly connected with the connecting blocks.

Preferably, the movable mechanism is including setting up in the second fixed plate on second connecting plate top, second fixed plate and second connecting plate fixed connection, just the slope of second fixed plate sets up, the second fixed plate passes through a plurality of elasticity columnar connection with second arc backup pad, the outside cover of elasticity post is equipped with the third spring, top one side of second arc backup pad is through a plurality of hinge swing joint with top one side of second connecting plate.

Preferably, second buffer gear includes a plurality of second through-holes of seting up on first fixed plate top, be equipped with second screw thread rotation axis in the second through-hole, the bottom and the backup pad fixed connection of second screw thread rotation axis, the outside cover of second screw thread rotation axis is equipped with the solid fixed ring of second that is located first fixed plate top, the outside cover of second screw thread rotation axis is equipped with the fourth spring that is located between first fixed plate and the backup pad.

Preferably, the inner wall of the second fixing ring is provided with a thread matched with the second thread rotating shaft.

Compared with the prior art, the invention has the following beneficial effects:

aiming at the defects of the existing unmanned aerial vehicle, through the matching action of the first connecting plate, the bottom plate, the first fixing plate, the supporting plate, the first buffer mechanism and the second buffer mechanism, when the unmanned aerial vehicle body vertically lands, the vertical direction of the unmanned aerial vehicle body is buffered, the influence of impact force on the unmanned aerial vehicle body is reduced, through the matching action of the bottom plate, the square hole, the buffer box, the supporting rod, the rotating shaft, the first arc-shaped supporting plate, the limiting rod and the supporting mechanism, when the unmanned aerial vehicle body obliquely lands forwards and backwards due to other reasons, the unmanned aerial vehicle body is buffered through the elasticity of the first spring, through the matching action of the second connecting plate, the second arc-shaped supporting plate and the movable mechanism, when the unmanned aerial vehicle body obliquely lands left and right due to other reasons, the unmanned aerial vehicle body is buffered through the elasticity of the elastic column and the third spring, and further when the unmanned aerial vehicle, the impact force in the twinkling of an eye when all can reducing unmanned aerial vehicle body and ground contact is to the influence that unmanned aerial vehicle body itself caused, and then reduces the possibility of unmanned aerial vehicle internal electronic part damage, has increased unmanned aerial vehicle's life.

Drawings

FIG. 1 is a schematic view of the overall structure of a descent structure for an unmanned aerial vehicle for preventing severe shaking according to the present invention;

FIG. 2 is a sectional view of a support bar structure of a descent structure for an unmanned aerial vehicle for preventing severe shaking according to the present invention;

FIG. 3 is an enlarged view of a portion of FIG. 2 at A;

FIG. 4 is an enlarged view of a portion of FIG. 2 at B;

FIG. 5 is a schematic structural view of a first buffer mechanism of a landing structure for an unmanned aerial vehicle for preventing severe shaking according to the present invention;

fig. 6 is a schematic structural view of a movable mechanism of a descent structure for an unmanned aerial vehicle for preventing violent shaking according to the present invention.

In the figure: 1. an unmanned aerial vehicle body; 2. a first connecting plate; 3. a base plate; 4. a square hole; 5. a buffer tank; 6. a support bar; 7. a rotating shaft; 8. a first fixing plate; 9. a support plate; 10. a first arc-shaped support plate; 11. a second connecting plate; 12. a second arc-shaped support plate; 13. a pressing plate; 14. moving the plate; 15. a telescopic rod; 16. a first spring; 17. a first through hole; 18. an annular groove; 19. a first threaded rotating shaft; 20. a first retaining ring; 21. rotating the disc; 22. a limiting plate; 23. a limiting rod; 24. a damping groove; 25. connecting blocks; 26. a second spring; 27. a limiting groove; 28. a limiting block; 29. a hinge; 30. a second fixing plate; 31. an elastic column; 32. a third spring; 33. a second through hole; 34. a second threaded rotating shaft; 35. a fourth spring; 36. a second retaining ring.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, such as "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in figures 1-6, a falling structure for preventing violent shaking for an unmanned aerial vehicle comprises an unmanned aerial vehicle body 1, a first connecting plate 2 is fixedly connected with the bottom end of the unmanned aerial vehicle body 1, a bottom plate 3 is arranged below the first connecting plate 2, the bottom plate 3 is connected with the first connecting plate 2 through a first buffer mechanism, square holes 4 are symmetrically formed in the two sides of the top end of the bottom plate 3, supporting rods 6 are arranged in the square holes 4, the supporting rods 6 are movably connected with the square holes 4 through rotating shafts 7, buffer boxes 5 are symmetrically arranged on the two sides of the top end of the bottom plate 3, the buffer boxes 5 are of a cavity structure with an open bottom end, the top ends of the supporting rods 6 extend into the buffer boxes 5, the supporting rods 6 are connected with the buffer boxes 5 through supporting mechanisms, limiting rods 23 located on the two sides of the supporting rods 6 are arranged in the square holes 4, a supporting plate 9 is arranged below the first fixing plate 8, the supporting plate 9 is connected with the first fixing plate 8 through a second buffer mechanism, first arc-shaped supporting plates 10 are symmetrically arranged at two ends of the supporting plate 9, a second connecting plate 11 is arranged on one side, away from the supporting plate 9, of each of the two supporting plates 9, a second arc-shaped supporting plate 12 is arranged on one side, away from the supporting plate 9, of each of the second connecting plates 11, and the second arc-shaped supporting plates 12 are connected with the second connecting plates 11 through a movable mechanism;

the supporting mechanism comprises two pressing plates 13 arranged in the buffer box 5, the two pressing plates 13 are respectively positioned on two sides of the supporting rod 6, the pressing plates 13 are in contact with the supporting rod 6, a moving plate 14 is arranged on one side, far away from the two pressing plates 13, of each of the two pressing plates 14, each of the moving plates 14 is connected with the corresponding pressing plate 13 through a plurality of telescopic rods 15, a first spring 16 is sleeved outside each of the telescopic rods 15, the moving plates 14 are connected with the buffer box 5 through a driving mechanism, when the unmanned aerial vehicle body 1 is inclined forwards and backwards due to other reasons, the first arc-shaped supporting plates 10 are in contact with the ground, the supporting rod 6 is driven by external force to rotate by taking the rotating shaft 7 as a rotating shaft center, the pressing plates 13 are driven by the; the driving mechanism comprises first through holes 17 symmetrically formed in two sides of the buffer box 5, an annular groove 18 is formed in the inner wall of each first through hole 17, a first threaded rotating shaft 19 is arranged in each first through hole 17, a first fixing ring 20 is arranged in each annular groove 18, the inner wall of each first fixing ring 20 is fixedly connected with each first threaded rotating shaft 19, one end of each first threaded rotating shaft 19 is fixedly connected with a rotating disc 21 located on the outer wall of the buffer box 5, the other end of each first threaded rotating shaft 19 penetrates through the movable plate 14, and one end of each first threaded rotating shaft 19 is connected with a limiting plate 22 located between the movable plate 14 and the pressing plate 13; the first threaded rotating shaft 19 is in threaded connection with the moving plate 14, the side wall of the moving plate 14 is in contact with the inner wall of the buffer box 5, the position of the moving plate 14 can be adjusted by rotating the rotating disc 21, the first threaded rotating shaft 19 adjusts the distance between the pressing plate 13 and the moving plate 14, the deformation degree of the first spring 16 is adjusted, and the elasticity of the first spring 16 is changed according to actual requirements; the first buffer mechanism comprises a shock absorption groove 24 formed in the bottom end of the first connecting plate 2, a connecting block 25 is arranged in the shock absorption groove 24, the top end of the connecting block 25 is connected with the inner wall of the top end of the shock absorption groove 24 through a plurality of second springs 26, the bottom end of the connecting block 25 is fixedly connected with the top end of the bottom plate 3, the unmanned aerial vehicle body 1 is buffered in the vertical direction through the elasticity of the second springs 26, and the influence of impact force on the unmanned aerial vehicle body 1 is reduced; limiting grooves 27 are symmetrically formed in the inner walls of the two sides of the damping groove 24, limiting blocks 28 are arranged in the limiting grooves 27, the limiting blocks 28 are fixedly connected with the connecting blocks 25, the positions of the connecting blocks 25 are limited, and the connecting blocks 25 are prevented from sliding out of the damping groove 24; the movable mechanism comprises a second fixing plate 30 arranged at the top end of the second connecting plate 11, the second fixing plate 30 is fixedly connected with the second connecting plate 11, the second fixing plate 30 is obliquely arranged, the second fixing plate 30 is connected with the second arc-shaped supporting plate 12 through a plurality of elastic columns 31, third springs 32 are sleeved outside the elastic columns 31, one side of the top end of the second arc-shaped supporting plate 12 is movably connected with one side of the top end of the second connecting plate 11 through a plurality of hinges 29, when the unmanned aerial vehicle body 1 is obliquely descended left and right due to other reasons, the second arc-shaped supporting plate 12 is contacted with the ground, the second arc-shaped supporting plate 12 rotates relative to the second connecting plate 11, the elastic columns 31 and the third springs 32 deform, and the unmanned aerial vehicle body 1 is buffered through the elastic force of the elastic columns 31 and the third springs; the second buffer mechanism comprises a plurality of second through holes 33 arranged at the top end of the first fixing plate 8, second threaded rotating shafts 34 are arranged in the second through holes 33, the bottom ends of the second threaded rotating shafts 34 are fixedly connected with the supporting plate 9, second fixing rings 36 positioned at the top end of the first fixing plate 8 are sleeved outside the second threaded rotating shafts 34, and fourth springs 35 positioned between the first fixing plate 8 and the supporting plate 9 are sleeved outside the second threaded rotating shafts 34; the inner wall of the second fixing ring 36 is provided with threads matched with the second thread rotating shaft 34, the elastic force of the fourth spring 35 is used for buffering the vertical direction of the unmanned aerial vehicle body 1, and the influence of impact force on the unmanned aerial vehicle body 1 is reduced.

It should be noted that, the invention is a landing structure for an unmanned aerial vehicle for preventing violent shaking, when the unmanned aerial vehicle body 1 vertically lands, the distance between the supporting plate 9 and the first fixing plate 8 changes, the distance between the bottom plate 3 and the first connecting plate 2 changes, and further the fourth spring 35 and the second spring 26 both deform, the vertical direction of the unmanned aerial vehicle body 1 is buffered through the elasticity of the fourth spring 35 and the second spring 26, the influence of impact force on the unmanned aerial vehicle body 1 is reduced, when the unmanned aerial vehicle body 1 lands obliquely forwards and backwards due to other reasons, the first arc-shaped supporting plate 10 contacts with the ground, and further the supporting rod 6 is driven by external force to rotate by taking the rotating shaft 7 as the rotating shaft center, further the bottom plate 3 drives the pressing plate 13 to move, the unmanned aerial vehicle body 1 is buffered through the elasticity of the first spring 16, and simultaneously the position of the moving plate 14 can be adjusted through the rotating disk 21 and the first thread rotating, and then change the distance between pressure board 13 and the movable plate 14, adjust the deformation degree of first spring 16, and then change first spring 16's elasticity according to actual demand, when unmanned aerial vehicle body 1 descends because of other reasons left right sides slope, second arc backup pad 12 and ground contact, and then second arc backup pad 12 is rotatory for second connecting plate 11, deformation takes place for elastic column 31 and third spring 32, elasticity through elastic column 31 and third spring 32, cushion unmanned aerial vehicle body 1, and then when unmanned aerial vehicle body 1 descends perpendicularly even slope, the impact force in the twinkling of an eye when all can reducing unmanned aerial vehicle body 1 and ground contact is to the influence that unmanned aerial vehicle body 1 itself caused, and then reduce the possibility of unmanned aerial vehicle internal electronic part damage, unmanned aerial vehicle's life has been increased.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.