CN115444658A

CN115444658A - Automatic telescopic headband structure

Info

Publication number: CN115444658A
Application number: CN202211270995.4A
Authority: CN
Inventors: 吴子乾
Original assignee: Tecmen Electronics Co Ltd
Current assignee: Tecmen Electronics Co Ltd
Priority date: 2014-09-09
Filing date: 2014-09-09
Publication date: 2022-12-09
Also published as: CN105395314A

Abstract

The invention relates to a headband structure, in particular for a face mask, comprising: an overhead restraint portion for attachment to the top of the wearer's head when worn; a head circumference restraining portion for attaching to the forehead and the nape of a wearer when worn; and an intermediate connecting portion connected between the two portions, wherein the crown restraining portion has at least two stretchable bands spaced apart from each other, each of the stretchable bands being controllably automatically stretchable with respect to the intermediate connecting portion, the crown restraining portion includes a front band for attaching to a forehead and a rear band for attaching to a back head, the front and rear bands being controllably automatically stretchable with respect to the intermediate connecting portion. The invention also relates to a mask with the headband structure.

Description

Automatic telescopic headband structure

The application is a divisional application of Chinese invention patent application No.201410456712.4 filed 9 months and 9 days 2014.

Technical Field

The present invention relates generally to headgear structures, particularly headgear structures used in protective masks such as welding masks.

Background

Headgear structures are typically lined with protective masks such as welding masks. The headgear structure is in direct contact with and between the head of the wearer and the mask shell for securely positioning the mask shell relative to the head of the wearer when the mask is in place.

The headband structure generally includes a crown restraining portion for providing a restraining force to the headband structure around the forehead and the back of the head of the wearer, and a crown restraining portion for providing a restraining force to the headband structure to attach to the crown of the head of the wearer.

For safety reasons, the headgear structure of the mask must require that the various components be held against the wearer's head with the proper force while worn so as to provide uniform cushioning of the mask shell and uniform support of the headgear structure when accidentally impacted by an external force to provide safety to the wearer. Thus, proper fit or lack thereof of the fit of the headband structure is critical to the design of the mask.

In order to solve the problem of inconsistent wearing clinging degree caused by inconsistent head sizes of wearers, the head circumference structure in the prior art usually adopts a manual adjusting structure to adjust the head band structure when the wearers wear the head circumference structure. However, the problem with such manual adjustment is: one is that the degree of appropriateness of each manual adjustment is closely related to the wearer's proficiency, and if the headgear structure is adjusted too tightly on the head, although the mask shell can be firmly positioned relative to the head and thus provide external force impact protection, the wearer is prone to becoming congested and stunned over time as the head is stressed by the headgear structure; the second is that if the wearer adjusts the headband structure too loosely on their head, the wearer does not feel discomfort, but the mask shell is not firmly positioned relative to the head and therefore does not provide adequate external force impact protection.

In addition, for some specialized masks (e.g., welding masks), one mask is often equipped with multiple operators for reasons of professional design of the mask itself and relatively expensive price. In this case, in addition to the problems noted above, manual adjustment of the headband structure between different wearer operators also increases the likelihood of mask damage.

Disclosure of Invention

In view of the above problems, the present invention provides a novel headband structure for a mask, which can automatically adjust the degree of tightness according to the head size, particularly the head circumference size, of a wearer when the headband structure is worn, thereby providing the wearer with an accurate degree of tightness of the headband structure and avoiding the possibility of damage to the headband structure due to manual adjustment by multiple persons. In addition, the headband structure according to the invention can automatically stretch and retract when being worn, thereby providing shorter wearing time compared with manual adjustment and being convenient for providing rapid protection for a wearer.

According to one aspect of the present invention, there is provided a headgear structure, in particular a mask headgear structure, comprising:

an overhead restraint portion for attachment to the top of the wearer's head when worn;

a head circumference restraining portion for attachment to the forehead and the hindbrain of a wearer when worn; and

an intermediate connecting portion connected between the two portions,

wherein the crown restraint portion has at least two spaced retractable straps each of which is controllably automatically retractable relative to the intermediate connecting portion to provide a restraining force of the headband structure on the crown of the head, and the circumference restraint portion includes a front strap for attaching to the forehead and a rear strap for attaching to the back of the head, the front strap and the rear strap being controllably automatically retractable relative to the intermediate connecting portion to provide a restraining force of the headband structure on the circumference of the head.

Optionally, the stretchable band and/or the front belt and/or the rear belt are automatically stretchable in a length direction and/or a volume increasing and decreasing direction in a controlled manner.

Optionally, the intermediate connecting portions are two and are located adjacent to the ears of the wearer when worn.

Optionally, each of the straps has one end fixed relative to one of the intermediate connecting portions and the other end extending into the other intermediate connecting portion, and an electric or pneumatic drive operatively connected to the end of the strap is provided in the other intermediate connecting portion for causing the strap to flex in a length or volume increasing or decreasing direction.

Optionally, the electric driving device or the air pump driving device is controlled by a switch arranged on the middle connecting part, so that the telescopic belt stretches.

Alternatively, the electric drive means is a motor, a rack is formed in a portion of the extensible band extending into the intermediate connecting portion, and the motor is connected to the extensible band via a gear engaged with the rack.

Optionally, a gear transmission, in particular a bevel gear pair, is provided between the motor and the gear.

Optionally, the front belt and/or the rear belt comprises a receiving seat and two connecting belts, one end of each connecting belt is fixedly connected with one middle connecting part, and the other end of each connecting belt is telescopically accommodated in the receiving seat.

Optionally, an electric driving device is arranged in the receiving seat and is operatively connected with the two connecting belts via a gear-rack transmission mechanism, so that the two connecting belts move relatively in the receiving seat along the length direction.

Alternatively, the electric driving device is a motor, a gear is rotatably disposed on one connecting belt and connected to an output shaft of the motor, and a rack engaged with the gear is disposed on the other connecting belt in a length direction.

Optionally, the electric drive is controlled by a switch provided on the receptacle, so that the two connecting straps are tightened or spread with respect to the receptacle.

Optionally, a knob is provided on the receptacle, by means of which the output shaft of the motor can be driven manually in rotation.

Optionally, the headband structure further comprises a detection means that detects the closeness of the crown-restraining portion and/or the crown-restraining portion on the wearer's head, the detection means causing the extension band of the crown-restraining portion and/or the front and rear bands of the crown-restraining portion to stop extending and contracting after the suitable closeness is reached.

Optionally, the headband structure further comprises a sensor for detecting whether the output shaft of the motor is subjected to resistance when rotating, and after the sensor detects the resistance, the motor is stopped; and/or a pressure sensor is provided on the side of the crown and/or crown restraining portions that contacts the wearer's head, and the motor is stopped after the pressure sensor detects a suitable contact pressure.

According to another aspect of the present invention, there is provided a mask, in particular a welding mask, lined with the headgear construction described above.

According to the invention, the constraint force of the headband structure can be automatically adjusted to a proper degree according to the head size of a wearer without manual adjustment of the wearer, so that the possibility of artificial damage to the headband structure is avoided; in addition, the proper clinging degree can be adjusted, the safety requirement is met, and the wearing time is shorter.

Drawings

The foregoing and other aspects of the present invention will be more fully understood from the following detailed description, taken together with the following drawings. It is noted that the proportions of the figures may be different for clarity of illustration, without affecting the understanding of the invention. In the drawings:

FIG. 1 schematically illustrates a perspective view of a headgear construction for a mask according to the present invention;

FIGS. 2 and 3 schematically show enlarged cut-away perspective views of the headband structure of FIG. 1 at left and right lateral connection locations, respectively; and is provided with

Fig. 4 schematically illustrates a cut-away enlarged perspective view of the headband structure shown in fig. 1 at a rear connection location.

Detailed Description

In the various figures of the present application, features that are structurally identical or functionally similar are denoted by the same reference numerals.

The following of the specification will only describe the headband structure of the mask. It will be clear to those skilled in the art that the headgear structure of the present invention is suitable for use with any suitable mask, such as a welding mask. The headband structure is secured to the inner liner of the mask in any manner known to those skilled in the art and will not be described in detail herein.

As shown in fig. 1, the headband structure generally includes a crown constraining portion 1 and a head circumference constraining portion 2. The crown-restraining portion 1 is primarily for providing a tightening force of the headband structure on the crown of the wearer's head, and the crown-restraining portion 2 is primarily for providing a tightening force of the headband structure on the front and rear head circumferences of the wearer. The crown constraint part 1 and the head circumference constraint part 2 are connected via two left and right intermediate connection parts 3, respectively. The intermediate attachment portion 3 may be formed, for example, by injection molding into a box shape, which functions to accommodate an adjustment structure of the crown restraint portion 1 (as will be described later). When worn, the intermediate connecting portion 3 is located substantially near the wearer's ear, e.g. above the ear.

For the sake of clarity, it is first specified that in the context of the present invention: in the headband structure, the direction diagonally inward on the paper surface of fig. 1 is the front, and the direction diagonally outward on the paper surface of fig. 1 is the rear.

The crown restraint portion 1 includes two flexible straps 1a and 1b. In order to avoid discomfort when in direct contact with the head of the wearer, the body of the two flexible straps 1a and 1b may be made of any suitable flexible and sufficiently strong strap, such as a plastic strap, a rubber strap, a fabric strap, or the like. Both ends of each of the flexible bands 1a and 1b are connected to the intermediate connecting portion 3 via connecting

bands

4a and 5b, respectively. Each connecting

strip

4a and 5b is made of a stronger material than the flexible strip, for example metal or rigid plastic. The connecting

straps

4a and 5b are primarily intended to provide a pulling force at the ends that tightens the flexible straps 1a and 1b.

As can be seen from fig. 1, the two flexible straps 1a and 1b are arranged spaced apart in the front-to-rear direction, thereby providing an even load distribution over the top of the wearer's head. In addition, it should be clear that the number of such flexible straps of the crown restraint portion 1 is not limited to the two shown in the figures. Three, four or more flexible straps may be provided as the structural design permits in order to provide a more even load distribution. Further, alternatively, each band portion of the crown restraining part 1 may be formed directly from the above-described connecting band, with a soft material wrapped around the connecting band as a portion directly contacting the crown of the wearer's head.

The specific configuration of each of the flexible straps 1a and 1b of the crown restraint portion 1 and its associated connecting

straps

4a and 5b is described in detail below with reference to fig. 2 and 3. Fig. 2 and 3 show enlarged perspective views of the middle connecting portion 3 in sections a and B, respectively. As can be seen from the figure, the connecting

strips

4a and 5b associated with each flexible strip 1a and 1b are only fixedly connected at one end to the housing of the intermediate connecting portion 3 and at the other end extend into the housing of the intermediate connecting portion 3. For example, as shown in fig. 2, the left side connecting strap 4a in fig. 1 is fixedly attached to the housing of the left side intermediate attachment portion 3, while the right side connecting strap 4a in fig. 1 extends into the housing of the right side intermediate attachment portion 3. For another example, as shown in fig. 3, the right connecting band 5b in fig. 1 is fixedly attached to the housing of the left intermediate connecting portion 3, and the left connecting band 5b in fig. 1 extends into the housing of the right intermediate connecting portion 3.

Taking fig. 2 as an example, the connection strip 4a can be fixed to the housing 3a of the intermediate connection portion 3 in any suitable manner known to those skilled in the art, such as riveting, gluing, snapping, etc. The connecting band 5b has a central elongated slot 8b extending in the longitudinal direction, on both longitudinally inward sides of which racks 8b' and 8b "are integrally formed, respectively. The attachment strip 5b may extend into the interior of the housing 3a, for example, through a slot formed in the outer wall of the housing 3a. It should be noted that the following description is only made for those parts essential for understanding the key technical solutions of the present invention. Other auxiliary parts such as the above-mentioned slots, a part for guiding the connection belt within the housing 3a, a part for supporting various gears, motors or circuit boards, etc., which will be described below, within the housing 3a should be well known to those skilled in the art. For example, the above-described grooves or portions supporting the respective gears in the housing 3a, etc. may be integrally formed at appropriate portions when the housing 3a of the intermediate connecting portion 3 is injection-molded, and therefore the description thereof will be omitted below.

As shown in fig. 2, a pair of

bevel gears

10 and 11 engaged with each other are installed in the housing 3a of the intermediate coupling part 3, wherein a gear 12 is integrally formed coaxially with the bevel gears 10, the gear 12 being located in the central elongated groove 8b of the coupling band 5b and engaged with the racks 8b' and 8b ″ of the central elongated groove 8b at the same time.

The bevel gear 11 is driven by a motor 13 in the housing 3a of the intermediate coupling part 3. In the housing 3a, the motor 13 is connected to a control circuit board 14, and electronic components for controlling the motor 13 and other corresponding electronic components such as a single chip microcomputer and the like are mounted on the circuit board 14. From this circuit board 14, data lines 15 lead out, which data lines 15 can supply the motor 13 via a power supply on the mask and/or make data connections with other electronics on the headband structure. After the motor 13 is activated, the bevel gear 11 is driven to rotate, and the bevel gear 11 in turn drives the bevel gear 10 engaged therewith to rotate and further drives the gear 12 to rotate. Since the gear 12 is engaged with the racks 8b' and 8b ″ of the connection belt 5b, the connection belt 5b is driven to move relative to the housing 3a. By controlling the direction of rotation of the output shaft of the motor 13, it is possible to control the direction of rotation of the bevel gear pairs 10 and 11 and thus the gear 12 accordingly and thereby whether the connecting belt 5b is further into the housing 3a or out of the housing 3a.

A rotary switch 16 as shown in fig. 1 can be mounted on the housing 3a of the intermediate connecting part 3 as shown in fig. 2, the rotary switch 16 can be connected to a control circuit board 14 of the motor 13 via a data line 15, for example, and the rotary switch 16 can correspondingly control the connecting strip 5b to extend and retract back and forth along the double arrow II with respect to the housing 3 by rotating the rotary switch forward or backward.

For example, a load cell (not shown) may be mounted on the output shaft of the motor 13, and the load cell is used for detecting whether the motor 13 is subjected to a blocking force after being started, and sending a signal to the control circuit board 14 after the motor 13 is subjected to the blocking force. The control circuit board 14 may be arranged to stop the motor 13 upon receiving the signal. Thus, after the wearer wears the headband structure of the invention on the top of the head and correspondingly turns on the knob switch 16, the flexible belt 1b can be automatically and gradually tightened under the driving of the connecting belt 5b, when the force sensor on the motor 13 is detected to be blocked after the headband structure is properly attached to the top of the head, the motor 13 is stopped, so that the flexible belt 1b is properly attached to the top of the head, and the tightness adjustment of the headband structure of the invention is not needed according to the experience of the wearer.

It should be appreciated that the load cell described above may be employed with any of the well-established products of the related art. Furthermore, such a sensor may also be a pressure sensor mounted on the overhead side of the flexible strap 1b. In this way, the pressure sensor can signal to the control circuit board 14 that the motor 13 is stopped after the flexible band 1b has tightened to a suitable extent on top of the head. It should be clear that any suitable sensor capable of measuring the appropriate tightness of the flexible band on the top of the head and signaling to the control circuit board 14 that the motor 13 is off could be used in the headband structure of the present invention as will occur to those of skill in the art.

Fig. 3 shows a structure similar to that of fig. 2, except that a connection band 5b is fixed on the housing 3a of the intermediate connection part 3 in fig. 3, and a connection band 4a extends into the housing 3a. Similarly to the connecting band 5b, the connecting band 4a has a central elongated slot 8a extending in the longitudinal direction, and racks 8a' and 8a ″ are also integrally formed on both sides of the elongated slot longitudinally inward, respectively. Likewise, a pair of

bevel gears

10 and 11 engaged with each other are installed in the housing 3a of the intermediate coupling part 3, wherein a gear 12 is integrally formed coaxially with the bevel gears 10, the gear 12 being located in the central elongated slot 8b of the connecting band 4a and engaged with the racks 8a' and 8a ″ of the central elongated slot 8a at the same time. The bevel gear 11 is driven by a motor 13 in the housing 3a of the intermediate coupling part 3. Inside the housing 3a, the motor 13 is connected to a control circuit board 14, on which board 14 are mounted electronics for controlling the motor 13 as well as other control electronics. A rotary switch 17 is mounted on the housing 3a of the intermediate connection portion 3 and can be connected to the control circuit board 14 of the motor 13 via a data line 15, for example. By rotating the knob switch 17 forward or backward, the connecting band 4a can be correspondingly controlled to extend and retract back and forth along the double-headed arrow II relative to the housing 3. The operation of the connection band 4a is the same as described above with reference to fig. 2, and therefore, will not be described in detail herein.

Although in the embodiment shown in fig. 2 and 3a

bevel gear pair

10 and 11 is used in the intermediate connecting part 3 to drive the connecting

belts

4a and 5b to extend and retract, any other suitable transmission means may be used in the solution of the invention. For example, spur gear pair transmission structures may be used instead of bevel gear pairs 10 and 11. Even for space saving purposes, the bevel gear pairs 10 and 11 may be omitted and the gear 12 may be mounted directly on the output shaft of the motor 13 for driving.

The motor 13 and the

connection belt

4a or 5b driven by the motor 13 to extend and retract substantially constitute a telescopic adjustment structure for realizing an automatic extending and retracting function for the flexible belt 1a or 1b. However, it should be apparent to those skilled in the art that such adjustment structure is not limited to only the illustrated embodiment. For example, alternatively, the flexible bands 1a and 1b may be made as elastic bands whose inner portions are hollow and inflatable, and both ends of the bands are connected to the intermediate connecting portion 3, respectively, and the hollow inner portions communicate with a small air pump installed in the intermediate connecting portion 3; the air pump is controlled by

switches

16 and 17, respectively, to inflate the interior of the elastic band so that the headband structure fits properly after being worn on the top of the head. Similarly, the air pump may be controlled by the aforementioned sensor to signal the air pump to stop after a suitable contact between the elastic band and the crown of the head is detected. It should be understood that the

switches

16 and 17 are not limited to the rotary switches shown in fig. 2 and 3, and that other types of switches, such as a two-way push switch, etc., may be employed in the headband structure of the present invention.

For another example, the flexible belts 1a and 1b may alternatively be arranged such that one end is directly fixedly connected to the output shaft of the motor 13 in the intermediate connecting portion 3, and the flexible belts may be wound or unwound on the output shaft as the output shaft rotates, thereby ensuring the flexible belts 1a and 1b to be stretched back and forth with respect to the intermediate connecting portion 3. It should be understood that any configuration that achieves the function of automatically telescoping the flexible straps 1a and 1b relative to the intermediate connecting portion 3 may be employed in the headband structure of the present invention.

Further, as shown in fig. 1, the head circumference restraining part 2 includes a front belt 2a and a rear belt 2b. The front strap 2a is intended to rest against the forehead of the wearer when worn and the rear strap 2b is intended to rest against the back of the head of the wearer when worn, thereby achieving restraint of the wearer's circumference of the head. Similar to the flexible belts 1a and 1b, the main body of the front belt 2a may be made of any suitable flexible and sufficiently strong belt such as a plastic belt, a rubber belt, a fabric belt, or the like. Both ends of the main body of the front belt 2a are connected to the intermediate connecting portion 3 via connecting belts 6a, respectively. Alternatively, the connecting strap 6a may be fixedly connected directly to the intermediate portion 3; or they may employ therebetween a telescopic adjustment structure as shown in fig. 2 and 3 or alternative embodiments of such adjustment structures as mentioned above.

The specific configuration of the rear belt 2b is described below with reference to fig. 4. The rear strap 2b comprises two connecting straps 7b. Each connecting strap 7b is fixed at one end to the housing 3a of a respective one of the intermediate connecting portions 3 and at the other end extends into a receiving seat 18 arranged between the two connecting straps 7b.

The receptacle 18 is an injection molded part and has a hollow interior. As shown in fig. 4, two connecting strips 7b are attached to each other to be slidably received in the receiving seat 18. The upper connecting band 7b may be formed with a central elongated slot 20 extending in the longitudinal direction, on both sides of which racks 20a and 20b are integrally formed, respectively. A gear 21 is rotatably attached to the lower connecting belt 7b. The gear 21 is capable of rotating about a shaft provided on the connecting belt 7b while meshing with the

racks

20a and 20b. A motor 22, a control circuit board 24, and a data line 23 connected between the motor 22 and the control circuit board 24 are mounted on the housing 3a of the intermediate connection portion 3. An output shaft of the motor 22 is connected to the gear 21, and the gear 21 is driven to rotate in the forward and reverse directions under the control of the circuit board 24, so that the two connection belts 7b can be extended and contracted relative to each other along the double-headed arrow I shown in fig. 1.

Additional wires 25 are connected to the circuit board 24 for powering it and/or for data connection to other electronics on the headband structure. The switch 27 arranged on the surface of the receptacle 18 as shown in fig. 1 can be connected to the control circuit board 24, for example, via a wire 25. After the headband structure of the present invention is worn on the head, the two connecting bands 7b are respectively extended and retracted along the double arrow I in the receptacle 18 by the driving of the motor 22 according to the left and right arrows of the switch 27 pressed by the wearer. It is contemplated that similar sensors as mentioned above may also be employed in or in association with motor 22 to signal motor 22 to stop upon detection of proper fit between the attachment strap and the head circumference.

As shown in fig. 4, the output shaft of motor 22 may also be connected to a knob 26 disposed on the outer surface of receptacle 18. The knob 26 can drive the output shaft of the motor 22 to rotate under the condition that the motor 22 is not electrified to be started, so that the two connecting belts 7b can be manually driven to mutually extend and retract along the double-headed arrow I through the knob 26, and more personalized options are provided for a wearer.

The motor 22, the knob 26 and the gear 21 and the

racks

20a and 20b of the two connecting belts 7b substantially constitute a telescopic adjustment structure of the rear belt 2b. However, it should be clear to those skilled in the art that the telescopic adjustment structure is not limited to the specific structure shown in fig. 4, and any adjustment structure that can achieve the telescopic movement of the two connecting bands 7b relative to the receiving seat 18 can be adopted in the technical solution of the present invention. For example, alternatively, two connecting belts 7b may be provided each with a

toothed rack

20a and 20b, the gear 21 being rotatably mounted in the receptacle 18 and simultaneously engaging with the toothed racks of the two connecting belts 7b, so that the motor 22 may also drive the connecting belts 7b to move relative to each other, under the control of the circuit board 24, so as to telescope with respect to the receptacle 18. Instead of the output shaft of the motor 22 being directly connected to the gear 21, the output shaft of the motor 22 may be connected to the gear 21 via any other suitable transmission mechanism such as a gear or a pulley.

It will be apparent to those skilled in the art from this disclosure that the expansion adjustment structures for the flexible straps 1a and 1b, the front strap 2a and the rear strap 2b may be interchanged with one another while meeting the structural design requirements. Further, it is conceivable to provide a contact sensor such as a pressure sensor on a portion of the headband structure of the present invention which can be brought into contact with the wearer, and when the wearer puts the headband structure on the head, the sensor automatically sends a signal to drive the motor to automatically tighten the crown restriction portion 1 and the head circumference restriction portion 2 in tandem or simultaneously.

As another example, the headband structure of the present invention may be configured to eliminate the receptacle 18 and employ only one intermediate connecting portion 3, such that the front strap, the rear strap, and the two flexible straps are fixed at one end and the other end extends simultaneously into the intermediate connecting portion 3 while being stretchable in a similar manner as described above with respect to the intermediate connecting portion, and also to achieve automatic stretching of the headband structure on the head of the wearer.

By adopting the headband structure, a wearer does not need to adjust the crown restraint part and the head circumference restraint part by himself or herself in a complicated way, all adjustments are automatically completed, and the headband structure is convenient and quick. In addition, because the adjustment is automatically completed, the damage which may occur after the headband structure is used by a plurality of persons for many times is avoided. In addition, the headband structure automatically tightens, so that the headband structure can be more appropriately suitable for the head sizes of different wearers, and the required tightness is ensured. Most importantly, the headgear construction according to the present invention, if employed in expensive specialized masks (e.g., specialized welding masks), allows one mask to be worn by multiple operators, significantly reducing equipment procurement costs.

Although specific embodiments of the invention have been described herein in detail, they have been presented for purposes of illustration only and are not to be construed as limiting the scope of the invention. Various substitutions, alterations, and modifications may be conceived of without departing from the spirit and scope of the invention.

Claims

1. A headgear structure, in particular a mask headgear structure, comprising:

a head circumference restraining portion for attaching to the forehead and the nape of a wearer when worn; and

an intermediate connecting portion connecting between the two portions,

wherein the crown restraint portion has at least two stretchable bands spaced apart from each other, each of the stretchable bands being automatically stretchable and contractible in a controlled manner with respect to the intermediate connection portion to provide a restraining force of the headband structure on the crown of the head, the head circumference restraint portion includes a front band for attaching to the forehead and a rear band for attaching to the back of the head, the front and rear bands being automatically stretchable and contractible in a controlled manner with respect to the intermediate connection portion to provide a restraining force of the headband structure on the circumference of the head, the intermediate connection portion being two in number and being located near the ears of the wearer when worn,

each telescopic band is formed by a flexible band and a connecting band respectively connected with two ends of the flexible band, so that each telescopic band is fixed relative to one intermediate connecting part at one end only through the corresponding connecting band and extends to the other intermediate connecting part at the other end through the corresponding connecting band, an electric driving device or an air pump driving device which is operatively connected with the corresponding connecting band at the end part of the telescopic band is arranged in the other intermediate connecting part, and is used for enabling the telescopic band to stretch in the length direction or the volume increasing and decreasing direction, and the connecting band is made of a material with higher strength than the flexible band.

2. The headgear structure according to claim 1, wherein the stretch strap and/or the front strap and/or the rear strap is automatically stretchable in a length direction and/or a volume increasing and decreasing direction in a controlled manner.

3. The headband structure according to claim 1, wherein the electric driving means or the air pump driving means is controlled by a switch provided on the intermediate connection part so that the extensible band is extended and contracted.

4. The headband structure according to claim 1 or 2, wherein the electric driving means is a motor, a rack is formed in a portion of the extensible band protruding into the intermediate connection portion, and the motor is connected to the extensible band via a gear engaged with the rack.

5. Headband construction according to claim 4, characterised in that a gear transmission, in particular a bevel gear pair, is provided between the motor and the gear.

6. The headband structure according to any one of claims 1 to 5, wherein the front band and/or the rear band comprises a receptacle and two connecting bands, one end of which is fixedly connected to an intermediate connecting part and the other end of which is telescopically received in the receptacle.

7. The headband structure of claim 6 wherein an electric drive is provided within the receptacle and is operatively connected to the two connecting straps via a rack and pinion mechanism such that the two connecting straps move longitudinally relative to each other within the receptacle.

8. The headband structure of claim 7, wherein the electric driving means is a motor, a gear is rotatably provided on one connecting band and connected to an output shaft of the motor, and a rack engaged with the gear is provided in a length direction on the other connecting band.

9. Headband construction according to claim 7 or 8, characterised in that the electric drive is controlled by a switch provided on the receptacle, so that the two connecting straps are tightened or spread with respect to the receptacle.

10. The headband structure of claim 8, wherein a knob is provided on the receptacle by which an output shaft of the motor can be manually driven to rotate.

11. The headband structure according to any one of the preceding claims, further comprising a detection means that detects how close the crown constraint part and/or the crown constraint part are on the wearer's head, the detection means causing the stretch band of the crown constraint part and/or the front and rear bands of the crown constraint part to stop stretching after the proper degree of close contact is reached.

12. The headband structure according to claim 4, 5 or 8, further comprising a sensor for detecting whether the output shaft of the motor is subjected to a resistance while rotating, and after the sensor detects the resistance, the motor is stopped; and/or a pressure sensor is provided on the side of the crown and/or crown restraining portions that contacts the wearer's head, and the motor is stopped after the pressure sensor detects a suitable contact pressure.

13. A mask, in particular a welding mask, wherein the mask lining is provided with a headgear arrangement according to any one of the preceding claims.

14. A welding mask, comprising a headgear structure, the headgear structure comprising:

and an intermediate connecting part connected between the two parts, wherein the crown constraint part has at least two telescopic bands spaced apart from each other, each of the telescopic bands is composed of a flexible band and a connecting band connected to both ends of the flexible band, and a bevel gear pair 10 and 11 is used in the intermediate connecting part to selectively drive the connecting band to be telescopic.