CN213635141U

CN213635141U - External folding flexible screen device

Info

Publication number: CN213635141U
Application number: CN202022851033.0U
Authority: CN
Inventors: 陳威仲; 董小慧; 万鹏程
Original assignee: Kunshan Kersen Science and Technology Co Ltd
Current assignee: Kunshan Kersen Science and Technology Co Ltd
Priority date: 2020-12-02
Filing date: 2020-12-02
Publication date: 2021-07-06
Anticipated expiration: 2030-12-02

Abstract

The utility model discloses an outer folding flexible screen equipment, including two backup pads, two connect through a rotation module between the respective same end of backup pad, when rotation module is in the closure state, two backup pads superpose, make its contained angle between the two be 0, when rotation module is in the expansion state, two the backup pad expandes to the contained angle between the two is 180; still include two support shells that supply the backup pad embedding, two in the backup pad imbeds a support shell separately, a drive module is connected with support shell, backup pad and rotation module respectively for the drive supports shell relative backup pad reciprocating sliding, and when the contained angle between two backup pads was 0, be in the contraction state between support shell and the backup pad, when the contained angle between two backup pads was 180, be in the extension state between support shell and the backup pad. The utility model discloses a open the synchronization in route between two backup pads for the whole screen of flexible screen is opening and shutting the in-process atress even, avoids producing fold, damage screen.

Description

External folding flexible screen device

Technical Field

The utility model relates to an outer folding flexible screen equipment belongs to electronic product technical field.

Background

With the development of science and technology, the use requirements of users for electronic products are higher and higher, which leads to the functions of the electronic products to be more and more diversified, and there are many new forms of electronic products, such as electronic devices with flexible screens: two side end parts of the flexible screen are respectively connected to two parts of the electronic equipment which can rotate relatively, so that the display area is enlarged as much as possible.

Although the flexible screen can further optimize the performance of the electronic product, after the folding-out type flexible screen is used for a period of time, a central area of the folding-out type flexible screen is folded, and even touch insensitivity or failure can be caused, so that the user experience is influenced.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing an outer folding flexible screen equipment, this outer folding flexible screen equipment has realized opening the synchronization in route between two backup pads for the whole screen of flexible screen is opening and shutting the in-process atress even, avoids producing fold, damage screen.

In order to achieve the above purpose, the utility model adopts the technical scheme that: the outer-folding flexible screen device comprises two supporting plates, wherein the same ends of the two supporting plates are connected through a rotating module, when the rotating module is in a closed state, the two supporting plates are superposed, so that an included angle between the two supporting plates is 0 degree, and when the rotating module is in an unfolded state, the two supporting plates are unfolded until the included angle between the two supporting plates is 180 degrees;

the screen support device comprises a support plate, a driving module, a support shell and a flexible screen, wherein the support plate is embedded into the support shell, the flexible screen is pasted on the support plate or the support shell, the two support plates are respectively embedded into one support shell, the driving module is respectively connected with the support shell, the support plate and the rotating module and used for driving the support shell to slide in a reciprocating mode relative to the support plate, when an included angle between the two support plates is 0 degree, the support shell and the support plate are in a contraction state, and when the included angle between the two support plates is 180 degrees, the support shell and the support plate are in an extension state;

the rotating module further comprises a center stopping sheet, and a first rotating sheet and a second rotating sheet which are respectively positioned at two sides of the center stopping sheet, wherein one ends of the first rotating sheet and the second rotating sheet, which are respectively close to the center stopping sheet, are connected with the center stopping sheet through a first mandrel, so that the center stopping sheet, the first rotating sheet and the second rotating sheet can rotate around the corresponding first mandrels;

the driving module further comprises a first connecting rod, a fourth connecting rod, a fifth connecting rod and a third connecting rod, wherein one end of the first connecting rod is connected with the supporting shell, one end of the fourth connecting rod is connected with the third core shaft, one end of the fifth connecting rod is connected with one end of the third connecting rod through the second connecting rod, one end of the fifth connecting rod penetrates through the other end of the third connecting rod and is embedded into a track groove formed in the supporting plate, the other end of the fifth connecting rod is hinged with one end, far away from the third core shaft, of the fourth connecting rod, and a supporting shaft penetrates through the supporting plate and is embedded into a mounting hole formed in the middle of the second connecting rod, so that the second connecting rod can rotate around the axial direction of the supporting shaft;

the first installation piece and the second installation piece are correspondingly arranged on the first rotating piece and the second rotating piece, the first installation piece is sleeved on a first mandrel and a second mandrel which are connected with the first rotating piece, the second installation piece is sleeved on a first mandrel and a second mandrel which are connected with the second rotating piece, a first gear is fixedly installed on the second mandrels which are positioned between the first rotating piece and the first installation piece and between the second rotating piece and the second installation piece respectively, at least two second gears which are meshed with each other are rotatably installed between the first rotating piece and the first installation piece and between the second rotating piece and the second installation piece respectively, wherein the second gear which is close to the first gear is meshed with the first gear, the second gear which is far away from the first gear is meshed with a third gear, and two ends of the third gear are correspondingly sleeved on the two first mandrels;

the first installation piece and the second installation piece are respectively provided with a gear part at one end close to each other, the gear parts are in meshing connection through at least two fourth gears, one ends of the two fourth gears are embedded into the middle of the third gear, the other ends of the two fourth gears are embedded into a baffle, and through holes for the first mandrel to pass through are formed in two ends of the baffle respectively;

correspond movable post, the spacing groove connection that matches each other through a set of at least between the backup pad that sets up and the support shell, the one end of activity post is movably installed in backup pad or support shell through a spring that is in the extrusion state, two the spacing groove sets up along backup pad and the relative movement direction interval between the support shell, and is two contained angle between the backup pad is 180 and when being in the expansion state, the other end embedding spacing inslot of activity post, when contained angle between two backup pads is 0 and when being in fold condition, the other end embedding another spacing inslot of activity post.

The further improved scheme in the technical scheme is as follows:

1. in the above scheme, the limiting groove is an arc-shaped groove formed in the supporting plate.

2. In the above scheme, the movable column is mounted on the support shell.

3. In the above scheme, the first mandrel is connected with the first installation piece, the second installation piece and the central stop piece through a check ring, and is used for limiting the movement of the first installation piece, the second installation piece and the central stop piece in the axial direction.

4. In the above scheme, the support shaft is rotatably connected with the support plate, and the support shaft is embedded into the mounting hole with the internal thread of the second connecting rod and is fixedly connected with the second connecting rod.

5. In the above-mentioned scheme, two correspond to install the magnet that at least a set of mutual actuation on the support shell, when the contained angle between two backup pads is 0 and is in fold condition, be located actuation connection between the magnet on two support shells respectively.

6. In the above scheme, the two groups of magnets are respectively positioned at two corners outside the two supporting shells.

Because of above-mentioned technical scheme's application, compared with the prior art, the utility model have the following advantage:

1. the utility model discloses outer folding flexible screen equipment, it is on the basis that realizes that flexible screen 0 ~180 opens and shuts, through backup pad and the relative movement between the support shell, realize displacement compensation, make the length on the surface that the in-process that opens and shuts supports flexible screen keep unchangeable, thereby the protection flexible screen can not produce the crease after long-time the use, local area touch failure wait condition can not appear yet, prolong the life of flexible screen, improve user's use and experience, still further guaranteed the path that opens and shuts at every turn unanimously, thereby guarantee the even atress of screen, avoid opening and shutting the condition that the process screen produced the crease because of the atress is uneven repeatedly.

2. The utility model discloses outer folding flexible screen equipment, its first installation piece, second installation piece are close to each other one serve and are provided with a gear portion separately, connect, two through two at least fourth gear engagement between the gear portion the one end embedding third gear middle part of fourth gear, two the other end embedding of fourth gear is installed in a baffle, and the through-hole that supplies first dabber to pass is opened respectively at the both ends of this baffle, sets up through the cooperation of first installation piece, second installation piece upper gear portion, fourth gear and second gear, third gear, first gear, has realized opening the synchronization in route between two backup pads for the whole screen of flexible screen atress of in-process that opens and shuts is even, avoids producing fold, damage screen.

3. The utility model discloses outer folding flexible screen equipment, its support plate that corresponds the setting is connected through at least a set of movable post, spacing groove that match each other between the support shell, the one end of activity post is movably installed on support plate or support shell through a spring that is in extrusion state, when the contained angle between two the support plates is 180 and is in the expansion state, the other end embedding spacing groove of activity post has realized spacing under the expansion state, guarantees the stability in the structure use, improves user experience; furthermore, it is two it corresponds on the support shell and installs at least a set of magnet that can actuation each other, and when the contained angle between two backup pads was 0 and was in fold condition, the actuation was connected between the magnet that is located two support shells respectively, has realized spacing under the folding state, improves the stability of structure in the use.

Drawings

Fig. 1 is a schematic structural view of the externally folded flexible screen device of the present invention in a folded state;

fig. 2 is a schematic structural view of the external folding flexible screen device of the present invention in an unfolded state;

fig. 3 is a structural side view of the external folding flexible screen device of the present invention in an unfolded state;

fig. 4 is a schematic structural diagram of a rotating module in the externally folded flexible screen device of the present invention;

fig. 5 is a schematic structural diagram of a rotating module in the externally folded flexible screen device of the present invention;

fig. 6 is a schematic structural diagram of a driving module in the externally folded flexible screen device of the present invention;

fig. 7 is a schematic structural view of a support plate in the externally folded flexible screen device of the present invention;

fig. 8 is an exploded view of the rotating module of the externally folded flexible panel apparatus of the present invention;

fig. 9 is a partial structural sectional view of the external folded flexible screen device of the present invention in an unfolded state;

fig. 10 is a partial structural sectional view of the flexible screen device of the present invention in a folded state;

fig. 11 is the utility model discloses flexible screen equipment fold condition under partial structure section two.

In the above drawings: 1. a support plate; 2. a rotation module; 3. a support housing; 4. a drive module; 5. a central stop piece; 6. a first rotating piece; 7. a second rotating piece; 8. a first mandrel; 9. a second mandrel; 10. a third mandrel; 11. a first link; 12. a second link; 13. a third link; 14. a fourth link; 15. a fifth link; 16. a track groove; 17. a support shaft; 18. a first mounting piece; 19. a second mounting piece; 21. a first gear; 22. a second gear; 23. a third gear; 24. a retainer ring; 25. a gear portion; 26. a fourth gear; 27. a baffle plate; 32. a magnet; 33. a movable post; 34. a limiting groove; 35. a spring.

Detailed Description

In the description of this patent, it is noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention; the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; furthermore, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, as they may be fixedly connected, detachably connected, or integrally connected, for example; 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 meaning of the above terms in this patent may be specifically understood by those of ordinary skill in the art.

Example 1: an outer folding flexible screen device comprises two supporting plates 1, wherein the same ends of the two supporting plates 1 are connected through a rotating module 2, when the rotating module 2 is in a closed state, the two supporting plates 1 are overlapped to enable an included angle between the two supporting plates to be 0 degree, and when the rotating module 2 is in an unfolded state, the two supporting plates 1 are unfolded to enable the included angle between the two supporting plates to be 180 degrees;

the screen support device is characterized by further comprising two support shells 3 for embedding the support plates 1 and a flexible screen pasted on the support plates 1 or the support shells 3, wherein the two support plates 1 are respectively embedded into one support shell 3, a driving module 4 is respectively connected with the support shells 3, the support plates 1 and the rotating module 2 and used for driving the support shells 3 to slide in a reciprocating mode relative to the support plates 1, when an included angle between the two support plates 1 is 0 degree, the support shells 3 and the support plates 1 are in a contracting state, and when the included angle between the two support plates 1 is 180 degrees, the support shells 3 and the support plates 1 are in an extending state;

the rotating module 2 further comprises a central stopping sheet 5, and a first rotating sheet 6 and a second rotating sheet 7 which are respectively positioned at two sides of the central stopping sheet 5, one end of each of the first rotating sheet 6 and the second rotating sheet 7 close to the central stopping sheet 5 is connected with the central stopping sheet 5 through a first mandrel 8, so that the central stopping sheet 5, the first rotating sheet 6 and the second rotating sheet 7 can rotate around the corresponding first mandrel 8, one ends of the first rotating sheet 6 and the second rotating sheet 7, which are far away from the central stopping sheet 5, are respectively connected with the supporting plate 1 through a second mandrel 9, the second mandrel 9 is relatively fixed with the supporting plate 1, the first rotating sheet 6 and the second rotating sheet 7 can rotate around the corresponding second mandrel 9, the first rotating sheet 6 and the second rotating sheet 7 are respectively and rotatably connected with a third core shaft 10 connected with the driving module 4;

the driving module 4 further comprises a first connecting rod 11 with one end connected with the supporting shell 3, a fourth connecting rod 14 with one end connected with the third mandrel 10, a fifth connecting rod 15 with one end connected with the supporting plate 1 in a sliding manner, and a third connecting rod 13, wherein the other end of the first connecting rod 11 is connected with one end of the third connecting rod 13 through a second connecting rod 12, one end of the fifth connecting rod 15 penetrates through the other end of the third connecting rod 13 and is embedded into a track groove 16 formed in the supporting plate 1, the other end of the fifth connecting rod 15 is hinged with one end of the fourth connecting rod 14 far away from the third mandrel 10, and a supporting shaft 17 penetrates through the supporting plate 1 and is embedded into a mounting hole formed in the middle part of the second connecting rod 12, so that the second connecting rod 12 can rotate around the axial direction of the supporting shaft 17;

the device is characterized by further comprising a first mounting piece 18 and a second mounting piece 19 which are arranged corresponding to the first rotating piece 6 and the second rotating piece 7, wherein the first mounting piece 18 is sleeved on a first mandrel 8 and a second mandrel 9 which are connected with the first rotating piece 6, the second mounting piece 19 is sleeved on the first mandrel 8 and the second mandrel 9 which are connected with the second rotating piece 7, at least two second gears 22 which are mutually meshed are respectively and fixedly mounted on the second mandrels 9 which are positioned between the first rotating piece 6 and the first mounting piece 18 and between the second rotating piece 7 and the second mounting piece 19, the second gears 22 which are close to the first gears 21 are meshed with the first gears 21, the second gears 22 which are far away from the first gears 21 are meshed with a third gear 23, two ends of the third gear 23 are correspondingly sleeved on the two first mandrels 8;

the first mounting piece 18 and the second mounting piece 19 are respectively provided with a gear part 25 at one end close to each other, the gear parts 25 are meshed and connected through at least two fourth gears 26, one end of each of the two fourth gears 26 is embedded into the middle of the third gear 23, the other end of each of the two fourth gears 26 is embedded into a baffle 27, and through holes for the first mandrel 8 to pass through are respectively formed at two ends of the baffle 27;

correspond and to be connected through a set of at least activity post 33, the spacing groove 34 that matches each other between the backup pad 1 that sets up and the support shell 3, the one end of activity post 33 is movably installed in backup pad 1 or support shell 3 through a spring 35 that is in the extrusion state, two relative movement direction interval setting between backup pad 1 and the support shell 3 is followed to the spacing groove 34, and is two contained angle between the backup pad 1 is 180 and when being in the expansion state, the other end embedding of activity post 33 is in a spacing groove 34, and contained angle between two backup pads 1 is 0 and when being in fold condition, the other end embedding of activity post 33 is in another spacing groove 34.

At least one group of magnets 32 which can be mutually attracted are correspondingly arranged on the two supporting shells 3, and when the included angle between the two supporting plates 1 is 0 degree and the supporting plates are in a folded state, the magnets 32 on the two supporting shells 3 are respectively attracted and connected; two groups of the magnets 32 are respectively positioned at two corners outside the two supporting shells 3;

the limiting groove 34 is an arc-shaped groove formed in the support plate 1; the supporting shaft 17 is rotatably connected with the supporting plate 1, and the supporting shaft 17 is embedded into a mounting hole with internal threads of the second connecting rod 12 and is fixedly connected with the second connecting rod 12.

Example 2: an outer folding flexible screen device comprises two supporting plates 1, wherein the same ends of the two supporting plates 1 are connected through a rotating module 2, when the rotating module 2 is in a closed state, the two supporting plates 1 are overlapped to enable an included angle between the two supporting plates to be 0 degree, and when the rotating module 2 is in an unfolded state, the two supporting plates 1 are unfolded to enable the included angle between the two supporting plates to be 180 degrees;

At least one group of magnets 32 which can be mutually attracted are correspondingly arranged on the two supporting shells 3, and when the included angle between the two supporting plates 1 is 0 degree and the supporting plates are in a folded state, the magnets 32 on the two supporting shells 3 are respectively attracted and connected;

the movable column 33 is mounted on the support housing 3; the first core shaft 8, the first mounting piece 18, the second mounting piece 19 and the central stopping piece 5 are connected through a retaining ring 24, and are used for limiting the movement of the first mounting piece 18, the second mounting piece 19 and the central stopping piece 5 in the axial direction.

When the externally folded flexible screen device is adopted, on the basis of realizing 0-180-degree opening and closing, displacement compensation is realized through relative movement between the supporting plate and the supporting shell, so that the length of the surface supporting the flexible screen in the opening and closing process is kept unchanged, the flexible screen is protected from generating creases after being used for a long time, the situations of touch failure in local areas and the like are avoided, the service life of the flexible screen is prolonged, the use experience of a user is improved, the consistency of the path of opening and closing at each time is further ensured, the uniform stress of the screen is ensured, and the situation that the creases are generated due to the uneven stress of the screen in the repeated opening and closing process is avoided;

furthermore, through the matching arrangement of the gear parts on the first mounting piece and the second mounting piece, the fourth gear, the second gear, the third gear and the first gear, the synchronization of opening paths between the two support plates is realized, so that the whole screen of the flexible screen is uniformly stressed in the opening and closing process, and wrinkles and screen damage are avoided;

in addition, the limit of the unfolded state and the folded state is realized, the stability of the structure in the using process is ensured, and the user experience is improved.

The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose of the embodiments is to enable people skilled in the art to understand the contents of the present invention and to implement the present invention, which cannot limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered by the protection scope of the present invention.

Claims

1. An outer folding flexible screen device, characterized in that: the foldable support comprises two support plates (1), wherein the same ends of the two support plates (1) are connected through a rotating module (2), when the rotating module (2) is in a closed state, the two support plates (1) are overlapped, so that an included angle between the two support plates is 0 degree, and when the rotating module (2) is in an unfolded state, the two support plates (1) are unfolded until the included angle between the two support plates is 180 degrees;

the screen support is characterized by further comprising two support shells (3) for embedding the support plates (1) and a flexible screen pasted on the support plates (1) or the support shells (3), wherein the two support plates (1) are respectively embedded into one support shell (3), a driving module (4) is respectively connected with the support shells (3), the support plates (1) and the rotating module (2) and is used for driving the support shells (3) to slide in a reciprocating mode relative to the support plates (1), when an included angle between the two support plates (1) is 0 degree, the support shells (3) and the support plates (1) are in a contraction state, and when an included angle between the two support plates (1) is 180 degrees, the support shells (3) and the support plates (1) are in an extension state;

the rotating module (2) further comprises a center stopping sheet (5) and a first rotating sheet (6) and a second rotating sheet (7) which are respectively positioned at two sides of the center stopping sheet (5), wherein one ends of the first rotating sheet (6) and the second rotating sheet (7) close to the center stopping sheet (5) are respectively connected with the center stopping sheet (5) through a first mandrel (8), so that the center stopping sheet (5), the first rotating sheet (6) and the second rotating sheet (7) can rotate around the corresponding first mandrel (8), one ends of the first rotating sheet (6) and the second rotating sheet (7) far away from the center stopping sheet (5) are respectively connected with the support plate (1) through a second mandrel (9), the second mandrel (9) is relatively fixed with the support plate (1), and the first rotating sheet (6) and the second rotating sheet (7) can rotate around the corresponding second mandrel (9), the first rotating sheet (6) and the second rotating sheet (7) are respectively and rotatably connected with a third mandrel (10) connected with the driving module (4);

the driving module (4) further comprises a first connecting rod (11) with one end connected with the supporting shell (3), a fourth connecting rod (14) with one end connected with the third mandrel (10), a fifth connecting rod (15) and a third connecting rod (13) with one end connected with the supporting plate (1) in a sliding way, the other end of the first connecting rod (11) is connected with one end of the third connecting rod (13) through a second connecting rod (12), one end of the fifth connecting rod (15) penetrates through the other end of the third connecting rod (13) and is embedded into a track groove (16) formed in the supporting plate (1), the other end of the fifth connecting rod (15) is hinged with one end of the fourth connecting rod (14) far away from the third mandrel (10), a supporting shaft (17) passes through the supporting plate (1) and is embedded into a mounting hole arranged in the middle of the second connecting rod (12), so that the second link (12) is rotatable about the axial direction of the support shaft (17);

the gear rack is also provided with a first mounting piece (18) and a second mounting piece (19) which are arranged corresponding to the first rotating piece (6) and the second rotating piece (7), the first mounting piece (18) is sleeved on a first mandrel (8) and a second mandrel (9) which are connected with the first rotating piece (6), the second mounting piece (19) is sleeved on the first mandrel (8) and the second mandrel (9) which are connected with the second rotating piece (7), a first gear (21) is fixedly mounted on the second mandrel (9) which is positioned between the first rotating piece (6) and the first mounting piece (18) and between the second rotating piece (7) and the second mounting piece (19), at least two second gears (22) which are mutually meshed are respectively rotatably mounted between the first rotating piece (6) and the first mounting piece (18) and between the second rotating piece (7) and the second mounting piece (19), wherein, the second gear (22) close to the first gear (21) is meshed with the first gear (21), the second gear (22) far away from the first gear (21) is meshed with a third gear (23), and two ends of the third gear (23) are correspondingly sleeved on the two first mandrels (8);

one ends, close to each other, of the first mounting piece (18) and the second mounting piece (19) are respectively provided with a gear part (25), the gear parts (25) are in meshing connection through at least two fourth gears (26), one ends of the two fourth gears (26) are embedded into the middle of the third gear (23), the other ends of the two fourth gears (26) are embedded into a baffle (27), and through holes for the first mandrel (8) to penetrate through are formed in two ends of the baffle (27);

correspond backup pad (1) that sets up and support and be connected through at least a set of movable post (33), spacing groove (34) that match each other between shell (3), the one end of activity post (33) is movably installed on backup pad (1) or support shell (3) through a spring (35) that is in the extrusion state, two relative movement direction interval setting between backup pad (1) and support shell (3) is followed in spacing groove (34), when two contained angle between backup pad (1) is 180 and when being in the expansion state, the other end embedding of activity post (33) is in one spacing groove (34), and when the contained angle between two backup pad (1) is 0 and when being in fold condition, the other end embedding of activity post (33) is in another spacing groove (34).

2. An out-folding flexible screen apparatus according to claim 1, wherein: the limiting groove (34) is an arc-shaped groove formed in the supporting plate (1).

3. An out-folding flexible screen apparatus according to claim 2, wherein: the movable column (33) is arranged on the supporting shell (3).

4. An out-folding flexible screen apparatus according to claim 1, wherein: the first mandrel (8) is connected with the first installation piece (18), the second installation piece (19) and the central stop piece (5) through a check ring (24) and used for limiting the movement of the first installation piece (18), the second installation piece (19) and the central stop piece (5) in the axial direction.

5. An out-folding flexible screen apparatus according to claim 1, wherein: the supporting shaft (17) is rotatably connected with the supporting plate (1), and the supporting shaft (17) is embedded into a mounting hole with internal threads of the second connecting rod (12) and is fixedly connected with the second connecting rod (12).

6. An out-folding flexible screen apparatus according to claim 1, wherein: two support and correspondingly install at least a set of magnet (32) that can attract each other on shell (3), when the contained angle between two backup pads (1) is 0 and is in fold condition, be located respectively and attract between two magnet (32) that support on shell (3) and connect.

7. An out-folding flexible screen apparatus according to claim 6, wherein: the two groups of magnets (32) are respectively positioned at two corners of the outer sides of the two supporting shells (3).