CN106892146B

CN106892146B - Automatic take-up and tensioning machine

Info

Publication number: CN106892146B
Application number: CN201710120629.3A
Authority: CN
Inventors: 李成都; 李建标; 邵波
Original assignee: Ningbo Xihe Machinery Co ltd
Current assignee: Ningbo Xihe Machinery Co ltd
Priority date: 2017-03-02
Filing date: 2017-03-02
Publication date: 2022-11-01
Anticipated expiration: 2037-03-02
Also published as: CN106892146A

Abstract

The invention discloses an automatic belt-retracting tensioning machine, wherein a fixed shaft and two side end parts of the fixed shaft are respectively sleeved with a ratchet wheel and can rotate around a shaft sleeve, one side of a base is provided with a coil spring, one side end part of the rotating shaft penetrates through the corresponding side wall part and is connected with one side end part of the coil spring, a pawl hinged to a pair of side wall parts of the base is arranged between the shaft sleeve and the fixed shaft, the fixed shaft is provided with a torsion spring which can drive the pawl to be meshed with the pair of ratchet wheels all the time without the influence of external acting force, a locking plate movably sleeved on the rotating shaft is arranged between the ratchet wheel at any side and the corresponding side wall part of the ratchet wheel, one side of the locking plate is provided with a first protruding part which is used for driving the pawl to be separated from the pair of ratchet wheels when the locking plate rotates, a protective shell used for sealing the base and the coil spring is also arranged outside the base, and the other side end part of the coil spring is fixed on the protective shell. The automatic belt-retracting tensioning machine solves the technical problem of prolonging the service life of the automatic belt-retracting tensioning machine, and has the advantage of long service life.

Description

Automatic take-up and tensioning machine

Technical Field

The invention relates to a tensioning machine, in particular to an automatic belt-retracting tensioning machine.

Background

Most of the tensioning machines on the market at present do not have the function of automatically recovering the woven belts, and after goods are unloaded, operators have to spend a large amount of time for tidying and recovering the woven belts.

In view of the above situation, the published chinese patent with patent number 200610050653.6 provides an automatic belt-retracting tensioning machine, which comprises a handle and a casing that are pivoted through a main shaft, wherein the handle and the casing are respectively provided with a large baffle plate assembly and a small baffle plate assembly, the small baffle plate assembly comprises a small baffle plate and a pressure spring, the main shaft is provided with a belt-retracting disk with ratchet wheels at both ends and a belt-retracting device for realizing the recovery of the woven belt through a volute spiral spring; the rear shaft of the machine shell is provided with a rotatable belt-winding brake plate and a double-torsion spring which acts on the brake plate and can ensure that the brake plate is tightly attached to the ratchet wheel on the take-up reel in the reverse direction; the large baffle plate component comprises a large baffle plate and a double-torsion spring acting on the large baffle plate, wherein the large baffle plate is provided with a manual button and a presser foot capable of triggering the belt-retracting brake plate to act, and the brake plate and the belt can form a tight non-return state or a separated non-return state by the pushing of the presser foot; two side walls of the shell are respectively provided with a tensioning operation area and a releasing and retracting area for the large baffle to move when the woven belt is tensioned and released or retracted; the front part of the handle is provided with an eccentric convex arc for pushing the brake plate and the small baffle, and the brake plate and the small baffle can be separated from the take-up reel by pushing the eccentric convex arc. Above-mentioned automatic take-up machine possesses outside ordinary take-up machine tightens up the function that the meshbelt binded the goods, and it can also retrieve the meshbelt automatically to can adjust the speed that the meshbelt was withdrawed wantonly or stop to take up the area at the in-process of retrieving the meshbelt, prevent that metal hook part from rebounding suddenly and hindering the people, easy and simple to handle, safe and reliable.

However, an automatic belt-retracting tensioner of the above-described construction still has significant technical drawbacks, in particular: considering that the main parts of the automatic belt-collecting and tensioning machine are made of metal materials, the direct exposure of the parts can not only affect the beauty of the product, but also the direct exposure of the metal parts can contact with the hands of an operator, the edges of the parts are sharp, discomfort can be brought to the operator, even the skin of the hands of the operator can be scratched, and potential safety hazards exist; further, considering that the automatic belt-retracting tensioner is required to be used in relatively severe weather conditions (such as rain and snow), the exposed metal parts are very susceptible to oxidation or other chemical reactions when contacted with water, which seriously affects the service performance and life of the automatic belt-retracting tensioner. If one automatic belt take-up tensioner of the structure is installed to protect the main body of the automatic belt take-up tensioner and is made of plastic, the handle in the automatic belt take-up tensioner structure is considered to be required to drive the ratchet wheel to rotate through reciprocating motion so as to realize belt take-up, the reciprocating motion amplitude of the handle is relatively large, the running track of the handle is also a section of arc line, so that a large enough opening must be reserved on the protection housing for the handle to act, the local part of the main body of the automatic belt take-up tensioner is still exposed, and the technical defects cannot be thoroughly and effectively solved.

Disclosure of Invention

The invention aims to solve the defects of the prior art and provide an automatic belt-retracting and tensioning machine with better sealing performance.

In order to achieve the above object, the present invention provides an automatic belt retracting tensioner, comprising a base having a groove-shaped cross section, a shaft sleeve having both side ends respectively sleeved with a ratchet in the groove of the base, the shaft sleeve being hinged to a pair of side wall portions of the base through a pivot axially passing through a shaft hole thereof, a coil spring provided at one side of the base, one side end of the pivot passing through the corresponding side wall portion and being connected to one end of the coil spring, a fixed shaft arranged in parallel with the shaft sleeve at one radial side of the shaft sleeve and having both side ends respectively extending to the corresponding side wall portions thereof for fixation, a pawl hinged to the pair of side wall portions of the base provided between the shaft sleeve and the fixed shaft, a torsion spring provided on the fixed shaft for urging the pawl to be always engaged with the pair of ratchet wheels without being affected by an external force, a locking plate movably sleeved to the pivot shaft between the ratchet wheel at any side and the corresponding side wall portion of the ratchet wheel, a first protruding portion for urging the pawl to be disengaged from the pair of ratchet wheels when the locking plate rotates, and a protection through hole provided on the other side wall portion of the base for protecting the pivot, and a protection of the pivot provided on the other side wall portion of the housing for protecting the pivot, and a protection of the coil spring.

The protective shell in the structure is preferably made of a plastic material with good stability, high strength and hardness and corrosion resistance.

When the automatic belt-retracting tensioning machine is actually used, a short woven belt needs to be connected to the fixed shaft in the structure, and a long woven belt needs to be wound on the shaft sleeve.

Therefore, as a preferred technical scheme, the application provides an automatic belt take-up tensioning machine, which comprises a long woven belt and a short woven belt in the structure, wherein an opening is axially arranged on the shaft sleeve, one side end part of the long woven belt is fixed on the rotating shaft, the other side end part of the long woven belt penetrates through the opening on the shaft sleeve, the protective shell is led out from a corresponding belt through hole on the protective shell after at least one circle of winding is carried out on the shaft sleeve, one side end part of the short woven belt is fixed on the fixed shaft, and the other side end part of the short woven belt penetrates through a corresponding belt through hole and then is led out of the protective shell.

According to the automatic belt-collecting tensioning machine, the torsion spring in the structure drives the pawls to be meshed with the pair of ratchet wheels all the time under the influence of no external acting force, namely, when the pair of ratchet wheels and one pawl are meshed, the shaft sleeve carrying the pair of ratchet wheels can only rotate around the rotating shaft in a single direction, and the rotating direction is the belt-collecting rotating direction of the shaft sleeve during the belt-collecting operation of the automatic belt-collecting tensioning machine. When the automatic belt-retracting tensioning machine needs to release the long woven belt, an external acting force is exerted on the locking plate, the first protruding part of the locking plate drives the pawl to be separated from the pair of ratchet wheels, the long woven belt drives the shaft sleeve to rotate back to the belt-retracting rotating direction under the traction of the external acting force, at the moment, the coil spring can synchronously realize the contraction or expansion, so that once the traction force exerted on the long woven belt disappears (whether the pawl is re-meshed to the pair of ratchet wheels or not is not considered at the moment), the long woven belt can automatically retract under the reset acting force of the coil spring until the bound object limits the belt to be retracted, the acting force exerted on the locking plate outside is ensured to disappear, the pawl is re-meshed to the pair of ratchet wheels under the driving of the torsion spring, at the moment, the external acting force is exerted on the rotating shaft to drive the shaft sleeve carrying the pair of ratchet wheels to start to rotate in the belt-retracting rotating direction, the long woven belt can gradually realize the locking, and the purpose of finally retracting and binding the bound object is realized. As can be seen from the above description, once the long webbing of the automatic webbing take-up and tensioning machine is released, it can be automatically taken up and wound around the sleeve without being obstructed or limited by external force; moreover, once external resistance is met in the recovery process of the long woven tape, the rotating shaft can be driven to further rotate in the tape-collecting rotating direction only by applying external acting force to rotate the rotating shaft, so that the continuous recovery of the long woven tape is realized, and considering that the rotating track of the rotating shaft around the central line of the rotating shaft does not need too large operating space, therefore, the protective shell additionally arranged outside the automatic belt-retracting tightening machine main body can seal the automatic belt-retracting tightening machine main body to the maximum extent, avoid metal material's automatic take-up main part and external environment direct contact to the at utmost, the automatic take-up main part of effectual protection ensures its validity of use and prolongs its life.

As a further preferred technical solution, the protective housing is mainly composed of three parts, namely a left half housing, a right half housing and a coil spring cover, wherein the coil spring is located in the coil spring cover, the coil spring cover is fixed on the side wall part of the base on the corresponding side of the coil spring, and the left half housing and the right half housing are combined and fixed to form an accommodating chamber for sealing the base, the coil spring and the coil spring cover.

Furthermore, a hand wheel is arranged on one side of the protective shell, and the hand wheel is fixed with the end part of the rotating shaft positioned outside the protective shell.

In the further technical scheme, the hand wheel can conveniently apply acting force on the rotating shaft, so that the rotating shaft is driven to rotate, and the aim of saving labor is fulfilled.

Furthermore, one side of the locking plate is provided with a second protruding part which is used for driving the pawl to press the pair of ratchet wheels when the locking plate rotates, the first protruding part is positioned below the second protruding part, a gap is formed between the first protruding part and the second protruding part, and the torsion spring drives the pawl to be clamped into the gap all the time without the influence of external acting force.

In the above further technical solution, the lock plate can urge the pawls engaged with the pair of ratchet wheels to disengage from the ratchet wheels, and at the same time, it can apply pressure to the pawls engaged with the pair of ratchet wheels, thereby improving the mutual frictional resistance between the engaging surfaces of the two. When the tensioning machine recovers the long woven belt by means of the restoring acting force of the coil spring, the lock plate with the structure can control the magnitude of the pressure value applied to the pawl, further control the magnitude of the friction resistance value of the meshing surfaces of the pawl and the ratchet wheel, finally control the recovery speed of the long woven belt and achieve the design purpose of serving as a brake switch.

In order to facilitate the effective and convenient hook of the long woven belt and the short woven belt to the bound object, the leading-out end parts of the long woven belt and the short woven belt are respectively connected with a metal hook.

The automatic belt retracting tensioning machine has the advantages that the woven belt can be automatically retracted, the retracting speed of the woven belt can be adjusted at will or the belt retracting can be stopped in the process of retracting the woven belt, the metal hook piece is prevented from rebounding suddenly to hurt people, and the automatic belt retracting tensioning machine is simple and convenient to operate, safe and reliable; meanwhile, the sealing structure has a series of advantages of structural sealing, small influence of the external severe environment on the use stability of the product, long service life and the like.

Drawings

FIG. 1 is an exploded view of an automatic take-up tensioner as provided in example 1;

FIG. 2 is an assembly view of an automatic take-up tensioner as provided in embodiment 1;

FIG. 3 is a schematic structural view of the automatic take-up tensioner provided in embodiment 1 after the protective housing is removed;

fig. 4 is a first schematic structural diagram of a protective casing provided in embodiment 1;

fig. 5 is a schematic structural diagram of a protective casing according to embodiment 1;

fig. 6 is a schematic structural view of a lock plate provided in embodiment 1;

fig. 7 is a schematic structural view of a shaft sleeve provided in embodiment 1;

fig. 8 is a schematic structural view of a protective casing provided in embodiment 2;

fig. 9 is a schematic structural view of a lock plate provided in embodiment 3;

FIG. 10 is a schematic view of the automatic take-up tensioner of embodiment 3 with the protective housing removed.

In the figure: the device comprises a base 1, a groove 1-1, a side wall part 1-2, a long woven belt 2, a short woven belt 3, a ratchet wheel 4, a shaft sleeve 5, an opening 5-1, a rotating shaft 6, a coil spring 7, an inner end part 7-1, an outer end part 7-2, a fixed shaft 8, a pawl 9, a torsion spring 10, a locking plate 11, a first bulge part 11-1, a handle part 11-2, a second bulge part 11-3, a notch 11-4, a protective shell 12, a tape through hole 12-1, a through hole 12-2, a left half shell 12-3, a right half shell 12-4, a coil spring cover 12-5, a hand wheel 13, a metal hook 14 and a handle sleeve 15.

Detailed Description

The invention is further illustrated by the following examples in conjunction with the drawings.

Example 1:

as shown in FIGS. 1-7, the present embodiment provides an automatic take-up tensioner comprising a base 1 having a cross-section of a groove 1-1, a long webbing 2 and a short webbing 3, a ratchet 4 sleeved on both side ends of the groove 1-1 of the base 1, a sleeve 5 having an opening 5-1 in an axial direction, the sleeve 5 being hinged to a pair of side wall portions 1-2 of the base 1 by a pivot shaft 6 axially penetrating through a shaft hole thereof, a coil spring 7 provided on one side of the base 1, a pair of pawls 9 hinged to the side wall portions 1-2 of the base 1 between the sleeve 5 and the fixed shaft 8 and connected to inner ends 7-1 of the coil springs 7, a fixed shaft 8 arranged in parallel to the sleeve 5 on a radial single side thereof and extending to the corresponding side wall portions 1-2 to be fixed, a pair of ratchet pawls 9 hinged to the side wall portions 1-2 of the base 1 provided between the sleeve 5 and the fixed shaft 8, a pair of pawl 10 provided on the side wall portions 1-2 hinged to the base 1, a movable locking plate 11 provided on the fixed shaft 8 for urging the pawl 9 to be engaged with the ratchet 4 on the ratchet 4, a movable locking plate 11 of the handle 2, and a pair of the handle portion 11 provided on the handle portion 11 for urging the handle 2 to be rotated by a user to be disengaged from the handle portion 11, the handle 2, the handle portion 11, the handle 2, the handle portion 11 for urging the handle portion 11, a protective shell 12 for sealing the base 1 and the coil spring 7 is further arranged outside the base 1, two tape-through holes 12-1 parallel to the rotating shaft 6 and a through hole 12-2 which is used for the handle part 11-2 of the locking plate 11 to penetrate through and is provided with a strip structure in the vertical direction are formed in the protective shell 12, the end part of the other side of the rotating shaft 6 sequentially penetrates through the corresponding side wall part 1-2 and the protective shell 12 and extends to the outside of the protective shell 12 to be connected with a hand wheel 13 in a transmission manner, the hand wheel 13 can conveniently apply acting force on the rotating shaft 6, so that the rotating shaft 6 is driven to rotate, the labor-saving design purpose is realized, and the outer end part 7-2 of the coil spring 7 is fixed on the protective shell 12; one side end of the long braid 2 is fixed on the rotating shaft 6, the other side end passes through the opening 5-1 on the shaft sleeve 5, and the protective shell 12 is led out from the corresponding tape through hole 12-1 on the protective shell 12 after at least one circle of winding is wound on the shaft sleeve 5, one side end of the short braid 3 is fixed on the fixed shaft 8, the other side end passes through the corresponding tape through hole 12-1 and then is led out of the protective shell 12, in order to facilitate the long braid 2 and the short braid 3 to be effectively and conveniently hooked to the bound object, a metal hook 14 is connected to the leading-out end of the long braid 2 and the short braid 3.

In the above-mentioned automatic belt-retracting tensioner, the torsion spring 10 in the structure drives the pawl 9 to engage with the pair of ratchet wheels 4 all the time under the influence of no external force, i.e. under the condition that the pair of ratchet wheels 4 is engaged with one pawl 9, the shaft sleeve 5 carrying the pair of ratchet wheels 4 can only rotate around the rotating shaft 6 in one direction, i.e. the belt-retracting rotating direction (clockwise rotating direction in fig. 1) of the shaft sleeve 5 during the belt-retracting operation of the automatic belt-retracting tensioner. When the automatic belt-retracting tensioning machine needs to release the long woven belt 2, the handle part 11-2 of the locking plate 11 is pressed, the first convex part 11-1 of the locking plate 11 drives the pawl 9 to disengage from the pair of ratchet wheels 4, the long woven belt 2 drives the shaft sleeve 5 to rotate back to the belt-retracting rotating direction (such as the counterclockwise rotating direction in fig. 1) under the traction of an externally applied force, at the same time, the coil spring 7 synchronously retracts, so that once the traction force externally applied to the long woven belt 2 disappears (whether the pawl 9 is re-engaged with the pair of ratchet wheels 4 or not is not considered at this time), the long woven belt 2 automatically retracts under the reset force of the coil spring 7 until the bound object limits the continuous belt retraction, and the pawl 9 is re-engaged with the pair of ratchet wheels 4 under the driving of the torsion spring 10 after ensuring that the externally applied force on the locking plate 11 disappears, at this time, the shaft sleeve 5 carrying the pair of ratchet wheels 4 is forced to rotate in the belt-retracting rotating direction by the externally applied force on the rotating shaft 6, and the long woven belt 2 can be gradually locked and finally locked.

The specific use mode of the automatic belt-retracting tensioning machine is as follows:

when binding articles, firstly, a user presses down the handle part 11-2 of the lock plate 11, the first bulge part 11-1 of the lock plate 11 rotates clockwise to jack the pawl 9, the pawl 9 is driven to be separated from the pair of ratchet wheels 4, the long woven belt 2 of the automatic belt take-up and tensioning machine is in a releasable state, the user pulls out the long woven belt 2, at the moment, the shaft sleeve 5 of the automatic belt take-up and tensioning machine rotates anticlockwise, and the long woven belt 2 and the metal hook 14 on the short woven belt 3 are hung on the corresponding position of the bound articles; then, the user loosens the long woven tape 2, and the pulled residual long woven tape 2 is recovered and wound on the rotating shaft 6 of the automatic tape-collecting tensioning machine under the action of the resetting force of the coil spring 7; finally, the user releases the acting force applied to the handle part 11-2 of the locking plate 11, the first bulge part 11-1 of the locking plate 11 rotates anticlockwise, the pawl 9 is meshed with the pair of ratchet wheels 4 again under the action of the resetting force of the torsion spring 10, the user rotates the hand wheel 13 in the clockwise direction at the moment, and the hand wheel 13 drives the rotating shaft 6 and the shaft sleeve 5 to synchronously rotate in the clockwise direction, so that the long woven belt 2 is gradually tightened;

when the long woven belt 2 and the short woven belt 3 are in a loose state, the user unloads the long woven belt 2 and the metal hook 14 on the short woven belt 3 in the loose state from the binding object, and then the long woven belt 2 can be recovered and wound on the rotating shaft 6 of the automatic belt take-up tensioner under the action of the reset force of the coil spring 7.

Example 2:

an automatic tape-collecting tensioner provided in this embodiment has a general structure similar to that of embodiment 1, as shown in fig. 8, but in this embodiment, the protection housing 12 is mainly composed of three parts, namely a left housing half 12-3, a right housing half 12-4 and a coil spring cover 12-5, the coil spring 7 is located in the coil spring cover 12-5, the coil spring cover 12-5 is fixed on the side wall part 1-2 of the base 1 on the corresponding side of the coil spring 7, and the left housing half 12-3 and the right housing half 12-4 are combined and fixed to form an accommodating chamber for sealing the base 1, the coil spring 7 and the coil spring cover 12-5.

In the automatic tape-retracting tensioning machine, considering that the coil spring 7 is a wearing part and can directly influence the automatic tape-retracting function of the automatic tape-retracting tensioning machine once damaged, a coil spring cover 12-5 is additionally arranged to independently accommodate the coil spring 7 in the embodiment, and the coil spring cover 12-5 is directly fixed on the base 1 of the automatic tape-retracting tensioning machine, so that the situation that the coil spring 7 collides or collides with other parts of the automatic tape-retracting tensioning machine is avoided to the greatest extent.

Example 3:

an automatic belt winding and tensioning machine provided in the present embodiment has a general structure similar to that of embodiment 2, as shown in fig. 9 and 10, but in this embodiment, a second protruding portion 11-3 for driving a pawl 9 to press a pair of ratchet wheels 4 when the locking plate 11 rotates is provided on one side of the locking plate 11, the first protruding portion 11-1 is located below the second protruding portion 11-3, and a gap 11-4 is formed between the first protruding portion 11-1 and the second protruding portion 11-3, and the torsion spring 10 drives the pawl 9 to be always locked in the gap 11-4 without the influence of an external force.

The lock plate 11 can urge the pawls 9 engaged with the pair of ratchet wheels 4 to disengage from the ratchet wheels 4, and by lifting the handle portion 11-2 of the lock plate 11, the second projecting portion 11-3 of the lock plate 11 rotates counterclockwise, and the lock plate 11 can also apply pressure to the pawls 9 engaged with the pair of ratchet wheels 4 through the second projecting portion 11-3, thereby increasing the mutual frictional resistance between the engaging surfaces of the pawls 9 and the pair of ratchet wheels 4. When the tensioning machine recovers the long woven belt 2 through the restoring acting force of the coil spring 7, the lock plate 11 with the structure can control the magnitude of the pressure value exerted on the pawl 9 by the second bulge part 11-3, further control the magnitude of the friction resistance value of the meshing surfaces of the pawl 9 and the ratchet wheel 4, finally control the recovery speed of the long woven belt 2, and realize the design purpose of being used as a brake switch.

when binding articles, firstly, a user presses down the handle part 11-2 of the lock plate 11, the first bulge part 11-1 of the lock plate 11 rotates clockwise to jack the pawl 9, the pawl 9 is driven to be separated from the pair of ratchet wheels 4, the long woven belt 2 of the automatic belt-retracting tensioning machine is in a releasable state, the user pulls out the long woven belt 2, at the moment, the shaft sleeve 5 of the automatic belt-retracting tensioning machine rotates anticlockwise, and the long woven belt 2 and the metal hook 14 on the short woven belt 3 are hung on the corresponding position of the bound articles; then, the user loosens the long woven tape 2, and the pulled residual long woven tape 2 is recovered and wound on the rotating shaft 6 of the automatic tape-collecting tensioning machine under the action of the resetting force of the coil spring 7; in the whole process of recovering the long woven tape 2, a user can control the pressure applied to the ratchet wheel 4 by the second bulge part 11-3 of the locking plate 11 by lifting the handle part 11-2 of the locking plate 11, further control the frictional resistance of the engaging surfaces of the pawl 9 and the pair of ratchet wheels 4, and finally control the recovery speed of the long woven tape 2.

Finally, the user releases the acting force applied to the handle part 11-2 of the locking plate 11, the first bulge part 11-1 of the locking plate 11 rotates anticlockwise, the pawl 9 is meshed with the pair of ratchet wheels 4 again under the action of the resetting force of the torsion spring 10, the user rotates the hand wheel 13 in the clockwise direction at the moment, and the hand wheel 13 drives the rotating shaft 6 to rotate clockwise synchronously with the shaft sleeve 5, so that the long woven belt 2 is tightened step by step;

when the long woven belt 2 is detached from an article, the user presses down the handle part 11-2 of the lock plate 11 again, and pulls out the long woven belt 2 again (at the moment, the long woven belt 2 only needs to be pulled out slightly), at the moment, the long woven belt 2 and the short woven belt 3 are in a loose state, the user detaches the metal hook 14 on the long woven belt 2 and the short woven belt 3 in the loose state from the bound article, and then the long woven belt 2 can be recovered and wound on the rotating shaft 6 of the automatic belt take-up tensioner under the action of the resetting force of the coil spring 7; in the whole process of recovering the long woven tape 2, a user can control the pressure applied to the ratchet wheel 4 by the second bulge part 11-3 of the locking plate 11 by lifting the handle part 11-2 of the locking plate 11, further control the frictional resistance of the engaging surfaces of the pawl 9 and the pair of ratchet wheels 4, and finally control the recovery speed of the long woven tape 2.

Claims

1. An automatic belt-retracting tensioner comprises a base (1) with a groove (1-1) shaped section, a shaft sleeve (5) with two side ends respectively sleeved with a ratchet wheel (4) is arranged in the groove (1-1) of the base (1), the shaft sleeve (5) is hinged to a pair of side wall parts (1-2) of the base (1) through a rotating shaft (6) axially penetrating through a shaft hole of the shaft sleeve, a coil spring (7) is arranged on one side of the base (1), one side end of the rotating shaft (6) penetrates through the corresponding side wall part (1-2) and is connected with one end of the coil spring (7), a fixed shaft (8) arranged in parallel with the shaft sleeve (5) is arranged on one radial side of the shaft sleeve (5), two side ends of the fixed shaft (8) respectively extend to the corresponding side wall parts (1-2) to be fixed, the automatic belt-retracting tensioner is characterized in that a pawl (9) hinged to the pair of side wall parts (1-2) of the base (1) is arranged between the shaft sleeve (5) and the fixed shaft (8), a locking plate (10) is arranged on one side wall part (6) of the fixed shaft (8) and is always meshed with the pawl (4) on one side wall part (4) under the ratchet wheel without the influence of the ratchet wheel, a locking plate (6) is arranged on any side of the ratchet wheel (4), one side of the locking plate (11) is provided with a first bulge part (11-1) for driving the pawl (9) to be separated from the pair of ratchet wheels (4) when the locking plate (11) rotates, the other side of the locking plate (11) extends outwards to form a handle part (11-2) which is convenient for external acting force to be applied to the locking plate (11) so as to drive the locking plate (11) to rotate, the base (1) is also provided with a protective shell (12) for sealing the base (1) and the coil spring (7), the protective shell (12) is provided with two strip through holes (12-1) parallel to the rotating shaft (6) and a handle part (11-2) for the locking plate (11) to penetrate, a through hole (12-2) is reserved on the running track of the handle part (11-2), the other end part of the rotating shaft (6) sequentially penetrates through the corresponding side wall parts (1-2) and the protective shell (12) and extends to the outside the protective shell (12), and the other end part of the coil spring (7) is fixed on the protective shell (12); one side of the locking plate (11) is provided with a second protruding part (11-3) which is used for driving the pawl (9) to press the pair of ratchet wheels (4) when the locking plate (11) rotates, the first protruding part (11-1) is positioned below the second protruding part (11-3), a gap (11-4) is formed between the first protruding part (11-1) and the second protruding part (11-3), and the torsion spring (10) drives the pawl (9) to be clamped into the gap (11-4) all the time without the influence of external acting force.

2. The automatic belt-retracting tensioning machine according to claim 1, characterized in that a hand wheel (13) is arranged on one side of the protective shell (12), and the hand wheel (13) is fixed with the end part of the rotating shaft (6) positioned outside the protective shell (12).

3. The automatic belt-retracting tensioning machine according to claim 1 or 2, characterized in that the protective housing (12) is mainly composed of three parts, namely a left half housing (12-3), a right half housing (12-4) and a coil spring cover (12-5), the coil spring (7) is positioned in the coil spring cover (12-5), the coil spring cover (12-5) is fixed on the side wall part (1-2) of the base (1) on the corresponding side of the coil spring (7), and the left half housing (12-3) and the right half housing (12-4) are combined and fixed to form an accommodating chamber for sealing the base (1), the coil spring (7) and the coil spring cover (12-5).

4. An automatic belt retracting and tensioning machine according to claim 1 or 2, characterized in that it further comprises a long webbing (2) and a short webbing (3), said sleeve (5) being provided with an opening (5-1) axially, one end of the long webbing (2) being fixed to the shaft (6) and the other end thereof passing through the opening (5-1) in the sleeve (5), and the sleeve (5) being wound at least once and then being led out of the protective housing (12) from a corresponding one of the belt passing through holes (12-1) in the protective housing (12), the short webbing (3) being fixed to the fixed shaft (8) at one end thereof and being led out of the protective housing (12) at the other end thereof passing through a corresponding one of the belt passing through holes (12-1).

5. An automatic take-up tensioner as claimed in claim 3, further comprising a long webbing (2) and a short webbing (3), said sleeve (5) having an opening (5-1) axially formed therein, said long webbing (2) having one end fixed to said shaft (6) and the other end passing through said opening (5-1) in said sleeve (5), said protective housing (12) being withdrawn from said protective housing (12) through a corresponding one of said through-holes (12-1) in said protective housing (12) after at least one winding of said sleeve (5), said short webbing (3) having one end fixed to said fixed shaft (8) and the other end passing through a corresponding one of said through-holes (12-1) and being withdrawn from said protective housing (12).

6. An automatic take-up tensioner as claimed in claim 4, characterised in that a metal hook (14) is attached to the leading end of each of said long (2) and short (3) webbings.

7. An automatic take-up tensioner as claimed in claim 5, characterised in that a metal hook (14) is attached to the leading end of each of said long (2) and short (3) webbings.