CN114002848A

CN114002848A - Head-mounted adjusting system and head-mounted device

Info

Publication number: CN114002848A
Application number: CN202111317990.8A
Authority: CN
Inventors: 张岩
Original assignee: Goertek Optical Technology Co Ltd
Current assignee: Goertek Techology Co Ltd
Priority date: 2021-11-08
Filing date: 2021-11-08
Publication date: 2022-02-01
Anticipated expiration: 2041-11-08
Also published as: CN114002848B

Abstract

The invention discloses a head-mounted adjusting system and a head-mounted device, which comprise a shell, a gas driving piece and a switch piece, wherein a sealing cavity is formed in the shell, and pressure gas is filled in the sealing cavity; one end of the gas driving piece is provided with a driving part which is sealed with the sealing cavity and is in sliding fit with the sealing cavity, the sealing cavity is separated by the driving part to form a first cavity and a second cavity which are positioned at two sides of the driving part, two side areas of the driving part are arranged in a difference mode, and the other end of the gas driving piece is used for being connected with the rope belt; the switch is used for controlling the connection and the disconnection of the first cavity and the second cavity. According to the technical scheme provided by the invention, the two cavities are communicated through the control switch piece to enable the pressure intensities to be the same, the two side areas of the driving part are different in size, the driving part is enabled to move by pressure difference generated on the two sides of the driving part, the switch piece is closed, the air pressure on the two sides of the driving part is in a balanced state, and the air driving piece is fixed relative to the shell, so that the pneumatic head-wearing type adjusting system is simple in adjusting structure and free of noise.

Description

Head-mounted adjusting system and head-mounted device

Technical Field

The invention relates to the field of electronic products, in particular to a head-mounted adjusting system and a head-mounted device.

Background

At present, VR rear head-wearing adjusting systems mainly have two types of bandage type adjusting systems and gear adjusting types. Wherein the bandage formula of adjusting system relies on elastic cord and magic to paste the cooperation and use, adjusts VR position back, and taut elastic cord is fixed with the magic subsides. The gear type is the main form of the existing high-end VR rear head-mounted adjusting system, and forward locking and reverse self-locking of the two racks are realized through meshing transmission of the two racks and the ratchet wheel.

At present, the binding belt type adjusting system and the gear type VR rear head-wearing adjusting system in the mainstream have some defects. The adjusting mode of the binding band has the defects of insufficient locking force, easy looseness, reduced adhesion of the magic tape along with the increase of the using time and the like. The gear adjusting type has the defects of complex structure, high noise, easy breakage of clamping teeth, low adjusting speed and the like.

Disclosure of Invention

The invention mainly aims to provide a head-mounted adjusting system and a head-mounted device, and aims to provide a pneumatic head-mounted adjusting system which is simple in adjusting structure and free of noise.

To achieve the above object, the present invention provides a head-mounted adjustment system, wherein the head-mounted adjustment system comprises:

the gas-tight device comprises a shell, a gas-tight cavity and a gas-tight cover, wherein the shell is internally provided with the gas-tight cavity;

the gas driving part is provided with a driving part which is sealed with the sealing cavity and is in sliding fit with the sealing cavity at one end, the sealing cavity is separated by the driving part to form a first cavity and a second cavity which are positioned at two sides of the driving part at intervals, two side areas of the driving part are arranged in a difference mode, and the other end of the gas driving part is used for being connected with a rope belt; and the number of the first and second groups,

and the switch piece is used for controlling the communication and the closing of the first cavity and the second cavity.

Optionally, the number of the gas driving components is two, one side of each of the two driving components, which is close to each other, is an inner side, the other side of each of the two driving components is an outer side, the first cavity is located at the inner side corresponding to the driving component, the second cavity is located at the outer side corresponding to the driving component, the two first cavities located at the inner sides of the two driving components are communicated with each other, and the two second cavities located at the outer sides of the two driving components are communicated with each other;

the inner side area of each driving part is larger than the outer side area, or the inner side area of each driving part is smaller than the outer side area.

Alternatively, the inner side areas of the two driving portions are equivalent, and the outer side areas of the two driving portions are equivalent.

The shell comprises a first shell and a second shell which are arranged oppositely, a first mounting groove is concavely arranged on one side of the first shell facing the second shell, a second mounting groove is concavely arranged on one side of the second shell facing the first shell, and the two gas driving pieces are clamped between the first shell and the second shell;

the first mounting groove and the second mounting groove constitute the seal cavity.

Optionally, the two gas driving members are oppositely arranged and have adjusting sections located in the sealed cavity, one of the adjusting sections of the two gas driving members is disposed in the first mounting groove, and the other of the adjusting sections of the two gas driving members is disposed in the second mounting groove;

the driving part is convexly arranged on one side of each gas driving part facing to the other gas driving part;

the inner sides of the two driving parts, the two adjusting sections, the side walls of the first mounting groove and the second mounting groove are enclosed to form two first cavities;

the outer sides of the two driving parts, the two adjusting sections, the side walls of the first mounting groove and the second mounting groove are enclosed to form two second cavities.

Optionally, the housing is provided with a first channel communicating the two second cavities;

a valve pin is arranged between the two driving parts, the shell is provided with a mounting hole corresponding to the valve pin, and the valve pin is provided with a second channel for communicating the two first cavities and a communication channel for communicating the first channel and the second channel;

and the switch piece is movably arranged on the valve pin and used for switching on or off the communication channel.

Optionally, the valve pin is provided with an installation channel communicated with the communication channel;

the switch piece is arranged in the installation channel and provided with an operation part exposed outside the installation channel and a stopping part arranged in the installation channel, and the operation part is used for driving the stopping part to move so that the stopping part has a cut-off position for cutting off the communication channel and a switch-on position far away from the communication channel.

Optionally, a reset member is further disposed in the mounting channel, the switch member is movably mounted in the mounting channel through the reset member, and the reset member is configured to provide a reset force when the blocking portion is switched from the on position to the off position.

Optionally, the reset piece is a compression spring;

the valve pin comprises a first pin body and a second pin body, and the first pin body is provided with the second channel, the communication channel and the mounting channel;

the second pin body is provided with a placement groove communicated with the installation channel, one end of the pressure spring is placed in the placement groove, and the other end of the pressure spring is connected with the stopping part.

Optionally, the head-mounted adjustment system further comprises an elastic pad disposed inside the housing.

The present invention also provides a head-mounted device comprising the head-mounted adjustment system described above, wherein the head-mounted adjustment system comprises:

Optionally, the headset is a VR device.

According to the technical scheme provided by the invention, pressure gas is filled in a sealed cavity in a shell, a gas driving piece is arranged on the shell, one end of the gas driving piece is provided with a driving part which is sealed with the sealed cavity and is in sliding fit with the sealed cavity, the sealed cavity is separated by the driving part so as to form a first cavity and a second cavity which are positioned at two sides of the driving part at intervals, the two side areas of the driving part are arranged in a different mode, the other end of the gas driving piece is used for being connected with a rope belt, and the shell is further provided with a switch piece used for controlling the connection and the disconnection of the first cavity and the second cavity. The first cavity is communicated with the second cavity by controlling the switch piece, the pressure intensity in the first cavity is the same as that in the second cavity, the two side areas of the driving part are different in size, so that the pressures acting on the two sides of the driving part are different, the pressure difference generated at the two sides of the driving part can drive the driving part to move, the driving part drives the whole gas driving part to slide relative to the shell, the other end of the gas driving part can drive the rope belt to movably adjust, when the rope belt is adjusted to a proper size, the switch piece is closed, the air pressure at two sides of the driving part is in a balanced state, the drive part gradually reaches the balanced state, and the relative casing position of gas driving spare is fixed for wear-type governing system fastening force keeps unchangeable, makes things convenient for the person of wearing to provide a regulation simple structure, and noiselessness pneumatic type wear-type governing system.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic perspective view of an embodiment of a head-mounted adjustment system provided by the present invention;

FIG. 2 is an exploded schematic view of the head-mounted adjustment system of FIG. 1;

FIG. 3 is a schematic cross-sectional view of the head-mounted adjustment system of FIG. 1;

FIG. 4 is a schematic cross-sectional view of the two driving portions of FIG. 3 moving to a closest position;

FIG. 5 is a schematic cross-sectional view of the two driving portions of FIG. 3 moving to a farthest state;

FIG. 6 is a schematic sectional view taken along line A-A in FIG. 3;

FIG. 7 is a schematic cross-sectional view taken along line B-B in FIG. 3;

FIG. 8 is a schematic cross-sectional view taken along line C-C of FIG. 3;

FIG. 9 is a schematic cross-sectional view taken along line D-D of FIG. 3;

FIG. 10 is a perspective view of the switch member of FIG. 1;

FIG. 11 is a cross-sectional view of the valve pin and switch assembly of FIG. 1.

The reference numbers illustrate:

the implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

At present, VR rear head-wearing adjusting systems mainly have two types of bandage type adjusting systems and gear adjusting types. Wherein the bandage formula of adjusting system relies on elastic cord and magic to paste the cooperation and use, adjusts VR position back, and taut elastic cord is fixed with the magic subsides. The gear type is the main form of the existing high-end VR rear head-wearing adjusting system, forward locking and reverse self-locking of the two racks are realized through meshing transmission of the two racks and the ratchet wheel, and the existing mainstream binding belt type adjusting system and the gear type VR rear head-wearing adjusting system have some defects. Wherein the adjusting mode of the bandage type adjusting system has the defects of insufficient locking force, easy looseness, reduced adhesion of the magic tape along with the increase of the using time and the like. The gear adjusting type has the defects of complex structure, high noise, easy breakage of clamping teeth, low adjusting speed and the like.

In order to solve the above problems, the present invention provides a head-mounted adjustment system, and fig. 1 to 11 are specific embodiments of the head-mounted adjustment system provided by the present invention.

Referring to fig. 1 to 3, the head-mounted adjustment system includes a housing 1, a gas driving member 2, and a switch member 3, wherein a sealed cavity 11 is formed in the housing 1, and the sealed cavity 11 is filled with a pressure gas; a driving part 21 which is sealed with the sealing cavity 11 and is in sliding fit with the sealing cavity 11 is arranged at one end of the gas driving part 2, the sealing cavity 11 is separated by the driving part 21, so that the sealing cavity 11 is separated to form a first cavity 11a and a second cavity 11b which are positioned at two sides of the driving part 21, the areas of two sides of the driving part 21 are arranged in a difference mode, and the other end of the gas driving part 2 is used for being connected with a rope belt; the switch member 3 is used for controlling the communication and closing of the first cavity 11a and the second cavity 11 b.

In the technical scheme provided by the invention, a sealed cavity 11 in a shell 1 is filled with pressure gas, a gas driving part 2 is arranged on the shell 1, one end of the gas driving part 2 is provided with a driving part 21 which is sealed with the sealed cavity 11 and is in sliding fit with the sealed cavity 11, the driving part 21 separates the sealed cavity 11 to separate the sealed cavity 11 into a first cavity 11a and a second cavity 11b which are positioned at two sides of the driving part 21, the areas of two sides of the driving part 21 are arranged in a different way, the other end of the gas driving part 2 is used for being connected with a rope belt, and the shell 1 is further provided with a switch part 3 which is used for controlling the communication and the closing of the first cavity 11a and the second cavity 11 b. The first cavity 11a and the second cavity 11b are communicated by controlling the switch component 3, the pressure intensity in the first cavity 11a and the second cavity 11b is the same, the two side areas of the driving part 21 are different in size, so that the pressures acting on the two sides of the driving part 21 are different, the pressure difference generated on the two sides of the driving part 21 can drive the driving part 21 to move, the driving part 21 drives the whole gas driving component 2 to slide relative to the shell 1, the other end of the gas driving component 2 can drive the rope to move and adjust, when the rope is adjusted to a proper size, the switch component 3 is closed, the gas pressures on the two sides of the driving part 21 are in a balanced state, the driving part 21 gradually reaches a balanced state, the position of the gas driving component 2 relative to the shell 1 is fixed, so that the fastening force of the head-mounted adjusting system is kept unchanged, the pneumatic head-mounted adjusting system is convenient for a wearer to use, and is simple in adjusting structure and free of noise.

Further, although the general rope belt has two ends, one end of the adjusting rope belt can be adjusted, but the adjusting rate is slower, in order to make the adjusting rate faster, please refer to fig. 2 to 5, in this embodiment, the two gas driving components 2 are provided, wherein the other end of one gas driving component 2 is connected with one end of the rope belt, the other end of the other gas driving component 2 is connected with the other end of the rope belt, one side of the two driving parts 21 close to each other is an inner side, the other side is an outer side, the first cavity 11a is located at the inner side corresponding to the driving part 21, the second cavity 11b is located at the outer side corresponding to the driving part 21, the two first cavities 11a located at the inner sides of the two driving parts 21 are communicated with each other, and the two second cavities 11b located at the outer sides of the two driving parts 21 are communicated with each other, wherein, each the area of the inside surface of drive division 21 is greater than the area in the outside, perhaps each the area of the inside surface of drive division 21 is less than the area in the outside, like this, acts on two the pressure of the inboard of drive division 21 is synchronous with the resultant force direction of the pressure that acts on the outside, promptly, when the pressure that acts on two the outside of drive division 21 is great, two gas driving piece 2 drive is close to the activity in step for the fag end is tightened up, works as when the pressure of the inboard of gas driving piece 2 is great, two gas driving piece 2 drive is synchronous keeps away from the activity, makes the fag end loosen, two like this gas driving piece 2 synchronous activity adjusts respectively the both ends of fag end, makes governing speed faster.

Of course, for convenience of adjustment, the two gas driving members 2 may be configured such that when the switch member 3 communicates with the first cavity 11a and the second cavity 11b, the two gas driving members 2 are close to each other, when the adjustment is performed to a suitable place, the switch member 3 is closed, when the rope is required to be loosened, the switch member 3 is kept in a state of communicating the two cavities, then the rope is pulled, and the rope pulls the two gas driving members 2 to overcome the pressure difference, so as to pull the two gas driving members 2 away from each other, thereby loosening the rope.

Further, in order to make the movable adjusting strokes of the two gas actuators 2 consistent, please refer to fig. 6 to 9, in this embodiment, the inner side areas of the two driving portions 21 are equivalent, and the outer side areas of the two driving portions 21 are equivalent, as can be known from F ═ PS, the pressure acting on the inner side of each driving portion 21 is F1, and the pressure on the outer side is F2, then the final resultant pressure acting on each driving portion 21 is Δ F1-F2 ═ PS1-PS2, when the inner side areas of the two driving portions 21 are equivalent, and the outer side areas of the two driving portions 21 are equivalent, the pressure differences Δ F acting on the two driving portions 21 are substantially equal, so that the strokes of the two driving portions 21 that are relatively close to or far from each other are synchronously equal.

Specifically, in order to facilitate the forming process and assembling of the two gas driving components 2, please refer to fig. 6 to 9, in this embodiment, the housing 1 includes a first housing 101 and a second housing 102 that are oppositely disposed, a first mounting groove 101a is concavely disposed on one side of the first housing 101 facing the second housing 102, a second mounting groove 102a is concavely disposed on one side of the second housing 102 facing the first housing 101, and the two gas driving components 2 are sandwiched between the first housing 101 and the second housing 102; the first mounting groove 101a and the second mounting groove 102a constitute the hermetic chamber 11. At the time of assembly, two gas driving members 2 may be assembled to the corresponding first housing 101 and second housing 102, respectively, and then the first housing 101 and second housing 102 are snap-fitted so that two mounting grooves form the sealed cavity 11.

Specifically, in order to facilitate the two gas driving members 2 to drive the rope belt to move, the two gas driving members 2 are partially disposed in the sealed cavity 11, and partially disposed outside the sealed cavity 11, in this embodiment, the two gas driving members 2 are disposed oppositely and have adjusting sections located in the sealed cavity 11, one of the adjusting sections of the two gas driving members 2 is disposed in the first mounting groove 101a, the other of the adjusting sections of the two gas driving members 2 is disposed in the second mounting groove 102a, the bottoms of the two gas driving members 2 are respectively connected to the corresponding housing in a sliding manner, the opposite sides of the two gas driving members 2 are filled with the high-pressure gas, one side of each gas driving member 2 facing the other gas driving member 2 is protruded with the driving portion 21, so that the two driving portions 21 are respectively disposed in the first mounting groove 101a and the second mounting groove 102a, the inner sides of the two driving portions 21, the side walls of the first mounting groove 101a and the second mounting groove 102a and the two adjusting sections located in the sealed cavity 11 together enclose to form two first cavities 11a, and the outer sides of the two driving portions 21, the side walls of the first mounting groove 101a and the second mounting groove 102a and the two adjusting sections located in the sealed cavity 11 together enclose to form two second cavities 11 b.

Further, referring to fig. 10 to 11, in this embodiment, the housing 1 is provided with a first passage 13 communicating two second cavities 11b, a valve pin 4 is disposed between two driving portions 21, the housing 1 is provided with a mounting hole 15 corresponding to the valve pin 4, such that the two first cavities 11a are respectively disposed at two sides of the valve pin 4, the valve pin 4 is provided with a second passage 41, the second passage 41 communicates the two first cavities 11a, in order to communicate the first passage 13 with the second passage 41, the valve pin 4 is further provided with a communicating passage 42, the communicating passage 42 communicates the first passage 13 with the second passage 41, the valve pin 4 is further provided with the switch member 3, the switch member 3 is movably disposed to connect or disconnect the communicating passage 42, the switch member 3 may be a switch valve disposed in the communicating passage 42, the present invention is not limited to this embodiment, and any device that can switch the communication passage 42 on or off is within the scope of the present invention.

Further, in order to facilitate the operation and adjustment of the wearer, please refer to fig. 10, in this embodiment, the valve pin 4 is provided with an installation channel 43 communicating with the communication channel 42, the switch member 3 is installed in the installation channel 43 to have an operation portion 31 exposed outside the installation channel 43 and a stop portion 32 arranged in the installation channel 43, the operation portion 31 is used to drive the stop portion 32 to move, so that the stop portion 32 has a cut-off position cutting off the communication channel 42 and a cut-on position far away from the communication channel 42, and the wearer can control the stop portion 32 to move by adjusting the operation portion 31 arranged outside the housing 1, so as to adjust the movement or positioning of the gas adjusting member.

Specifically, the operating portion 31 is operated by the wearer to control the stopping portion 32 by manually pushing the operating portion 31 to move between the off position and the on position, in this embodiment, a resetting member 5 is further disposed in the mounting channel 43, the switch member 3 is movably mounted in the mounting channel 43 through the resetting member 5, the resetting member 5 is used to provide a resetting force when the stopping portion 32 is switched from the on position to the off position, so that when the stopping portion 32 is in the on position by the operation of the operating portion 31 by the wearer, the gas driving member 2 is adjusted, when the tightness of the rope is determined to be appropriate by the wearer, only the operating portion 31 needs to be released, and the switch member 3 is reset through the resetting member 5, so that the stopping portion returns to the off position again, the arrangement is convenient for the operation of the wearer.

Further, referring to fig. 11, in this embodiment, the reset member 5 is a compression spring, so as to facilitate installation of the compression spring and the switch member 3, the valve pin 4 may be divided into two parts, that is, the valve pin 4 includes a first pin body 4a and a second pin body 4b, the first pin body 4a is provided with the second channel 41, the communication channel 42 and the installation channel 43, the second pin body 4b is provided with a placement groove 44 communicated with the installation channel 43, one end of the compression spring is placed in the placement groove 44, and the other end of the compression spring is connected with the stopper 32, so that when the valve pin 4 and the switch member 3 are assembled, the first pin body 4a and the second pin body 4b may be separated first, the compression spring may be placed in the placement groove 44, the switch member 3 may be installed in the installation channel 43, and then the first pin body 4a and the second pin body 4b may be covered and fixed together, the fixed first pin body 4a and the second pin body 4b are then placed and installed in the sealed cavity 11 from the installation hole 15.

Further, in consideration of the wearing comfort of the wearer, in this embodiment, the head-mounted adjustment system further includes an elastic pad 6, the elastic pad 6 is disposed inside the housing 1, the elastic pad 6 directly contacts with the skin of the wearer, and the elastic pad 6 has elasticity, so that when the head-mounted adjustment system is fixed on the head of the wearer, the elastic pad 6 elastically contacts with the skin, and the wearer does not feel uncomfortable, and when the gas adjustment member is adjusted, if the gas adjustment member is inadvertently adjusted to be too tight, the wearer does not suffer from pressure damage.

The present invention further provides a head-mounted device, where the head-mounted device includes the head-mounted adjustment system, and it should be noted that the head-mounted adjustment system is the head-mounted adjustment system, that is, the head-mounted device includes the head-mounted adjustment system, and the specific structure of the head-mounted adjustment system refers to the embodiments described above.

Further, the head-mounted device can be the miner wear the lamp, can be the magnifying glass of wearing, can also wear goggles etc. in this embodiment, the head-mounted device is the VR device, the VR device includes VR vision device and foretell head-mounted governing system, through head-mounted governing system adjusts the elasticity of wearing the fag end for when the person of wearing watches VR vision device in the use, more convenient and comfortable.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A head-mounted adjustment system, comprising:

2. The head-mounted adjustment system of claim 1, wherein the gas driving member is provided in two, one side of the two driving portions adjacent to each other is an inner side, the other side is an outer side, the first cavity is located at the inner side corresponding to the driving portions, the second cavity is located at the outer side corresponding to the driving portions, the two first cavities located at the inner sides of the two driving portions are communicated with each other, and the two second cavities located at the outer sides of the two driving portions are communicated with each other;

3. The head-mounted adjustment system of claim 2, wherein the inner side areas of the two drive portions are equivalent and the outer side areas of the two drive portions are equivalent.

4. The head-mounted adjustment system of claim 2, wherein the housing comprises a first housing and a second housing disposed opposite to each other, a first mounting groove is recessed in a side of the first housing facing the second housing, a second mounting groove is recessed in a side of the second housing facing the first housing, and the two gas driving members are sandwiched between the first housing and the second housing;

5. The head-mounted adjustment system of claim 4, wherein the two gas drivers are disposed in opposing relation and have adjustment sections located within the sealed chamber, one of the adjustment sections of the two gas drivers being disposed in the first mounting slot and the other of the adjustment sections of the two gas drivers being disposed in the second mounting slot;

6. A head-mounted adjustment system according to claim 3, characterized in that the housing is provided with a first channel communicating two of the second cavities;

7. The head-mounted adjustment system of claim 6, wherein the valve pin defines a mounting passage in communication with the communication passage;

8. The head-mounted adjustment system of claim 7, wherein a reset member is further disposed in the mounting channel, the switch member is movably mounted to the mounting channel via the reset member, and the reset member is configured to provide a reset force when the blocking portion is switched from the on position to the off position.

9. The head-mounted adjustment system of claim 8, wherein the return member is a compression spring;

10. A headgear comprising a head mounted adjustment system according to any one of claims 1 to 9.