CN110783746B

CN110783746B - Connector device with protective door

Info

Publication number: CN110783746B
Application number: CN201910901582.3A
Authority: CN
Inventors: 谭国锋; 姚勇
Original assignee: China Aviation Optical Electrical Technology Co Ltd
Current assignee: China Aviation Optical Electrical Technology Co Ltd
Priority date: 2019-09-23
Filing date: 2019-09-23
Publication date: 2021-05-18
Anticipated expiration: 2039-09-23
Also published as: CN110783746A

Abstract

The invention relates to a connector device with a protective door. Connector device with guard gate, including plug, socket, guard gate and mechanism of opening the door, the mechanism of opening the door is including pushing away piece and slider, push away the piece and convert the guiding motion of slider into through the cooperation of slope fitting surface with the guiding motion who pushes away the piece with the top, the guard gate is articulated door plant, the hinge axis of door plant is parallel with the direction moving direction who pushes away the piece, the door plant is connected with link mechanism's form with the slider, link mechanism is used for making the guiding motion of slider convert the rotation of door plant in order to realize opening and close of door plant. The sliding block is pushed by the pushing piece of the door opening mechanism, the protective door is opened to enable the plug and the socket to be inserted and closed, the pushing piece and the sliding block are matched through an inclined plane to convert the displacement of the pushing piece into the displacement of the sliding block, the door plate is enabled to translate on a plane perpendicular to the direction of guiding and moving of the pushing piece, and the problem of low protective performance of the connector caused by the long stroke of the protective door is solved.

Description

Connector device with protective door

Technical Field

The present disclosure relates to connectors, and particularly to a connector with a protective door.

Background

The electric connector can realize signal transmission and energy supply between two active devices, is widely applied to the fields of electronics, electrical appliances, ordnance, aviation, aerospace and the like, simplifies the assembly process of equipment, enables component replacement to be simpler, improves maintainability and has high assembly efficiency. The inside contact piece of electric connector receives the corruption, perhaps receives can cause electric connector to connect after the erosion of sleet, and the main mode that protects at present to the contact is at electric connector's tip installation shield, like the connector in the chinese utility model patent of the grant bulletin number CN203205617U, the tip of its plug is provided with the shield, when connecting electric connector, manually opens the shield, then inserts and closes. However, the dust cover needs to be manually opened when the electric connector is plugged, and needs to be manually covered at the end part of the plug when the electric connector is separated, so that the use process is complicated.

The invention discloses a plug-in type dustproof connector in Chinese invention patent application with application publication number CN107666063A, which comprises a plug and a socket, wherein a protective door is hinged on the plug, a locking device for controlling the closing of the protective door is further arranged on the plug, the locking device is specifically a torsion spring, a door opening mechanism for opening the protective door is arranged on the socket, the door opening mechanism is a push rod fixed on the socket, when the connector is plugged, the push rod pushes one side of the protective door, the protective door is opened by depending on the lever principle, the plug and the socket can be plugged, when the plug is separated from the socket, the protective door automatically covers the plug under the action of the torsion spring, and a contact device in the plug is protected.

The plug-in type dustproof connector can automatically open or close the protective door in the process of plugging and separating, the protective door does not need to be manually operated, but the hinge axis of the protective door is perpendicular to the moving direction of the push rod, so that the protective door needs to be turned over by 90 degrees when in action, the plug is completely opened or closed, meanwhile, the door opening mechanism needs to be set to be longer, so that the protective door can have enough space between the plug and the socket for the protective door to turn over, the size of the door opening mechanism is inevitably increased, the protective door rotates around the hinge axis when being opened or closed, the stroke is longer, the opening time of the protective door is prolonged, the protective door cannot play a good protection effect, in addition, the protective door can cause larger air flow disturbance in the turning process, an ash layer enters the connector, and corrodes a contact part, the shielding performance of the connector is reduced.

Disclosure of Invention

The invention aims to provide a connector device with a protective door, which is used for solving the problem of low protective performance of a connector caused by long stroke when the protective door is opened or closed in the prior art.

In order to achieve the purpose, the technical scheme of the invention is as follows: connector device with guard gate, including plug, socket, setting guard gate between plug and socket and be used for driving the mechanism of opening door that the guard gate was opened, the mechanism of opening door includes the slider that pushes away the piece and the plug direction setting of perpendicular to connector that set up along the plug direction of connector, push away the piece and convert the guide motion of slider into the guide motion of slider through the cooperation of slope fitting surface with the guide motion that pushes away the piece with the top, the guard gate is articulated door plant, the articulated axis of door plant is parallel with the plug direction of connector, the door plant is connected with link mechanism's form with the slider, link mechanism is used for making the guide motion of slider convert the rotation of door plant into in order to realize opening and close of door plant.

The invention has the beneficial effects that: the protective door is arranged between the plug and the socket and used for protecting a contact element inside the plug or the socket when the plug is separated from the socket, the sliding block is pushed by a pushing piece of the door opening mechanism, the protective door is opened to enable the plug and the socket to be inserted and closed, the pushing piece is arranged in a guiding mode along the inserting and pulling direction of the connector, the pushing piece can be pushed when the connector is inserted and pulled, the pushing piece is pushed to move in the inserting and pulling direction of the connector, the pushing piece and the sliding block are matched through an inclined plane to convert the displacement of the pushing piece into the guiding movement of the sliding block, the hinge axis of the door plate is parallel to the inserting and pulling direction of the connector, the door plate and the sliding block are connected in a connecting rod mechanism mode, the connecting rod mechanism can convert the guiding movement of the sliding block into the rotation of the door plate to further realize the opening and closing of the door plate, and when the door plate rotates around the hinge axis, the door plate, need not reserve the space that supplies the guard gate upset between plug and socket, reduced the influence that the guard gate caused the connector when opening and closing, compare around the upset of hinge axis with the guard gate among the prior art, the guard gate stroke is shorter, and the guard gate adopts the mode of translation to open and shut, can not arouse the air current disturbance, has avoided the dust to get into in the connector, has improved the barrier propterty of connector.

Further, the connecting rod mechanism is a crank-slider mechanism. Has the advantages that: each component in the crank block structure is in a hinged form, so that a hinged pair is convenient to process, the transmission precision is also favorably ensured, and the accurate action of the door plate is ensured.

Furthermore, the two door panels are arranged and are mutually involutory when being closed; each door plate comprises a shielding part and a driving arm, the driving arms of the two door plates are arranged in a crossed manner, and a hinge shaft of each door plate is positioned at the crossed point of the driving arms; and a connecting rod is arranged between the tail end of the driving arm and the sliding block, two ends of the connecting rod are respectively hinged with the driving arm and the sliding block, and the connecting rod, the driving arm and the sliding block form a crank sliding block mechanism taking the driving arm as a crank. Has the advantages that: the driving arms are arranged in a crossed manner, so that the structure is compact, the occupied space is small, and the arrangement of the connecting rods is convenient.

Further, the hinge shaft of the door panel is located at a side of the driving arm adjacent to the link for driving the movement of the shielding part in the form of a laborious lever. Has the advantages that: the protection door is beneficial to reducing the movement stroke required by the sliding block, and is more beneficial to reducing the stroke when the protection door is opened or closed and reducing the air flow disturbance, thereby further improving the protection performance of the connector.

Further, the driving arm sinks relative to the shielding portion in a moving direction of the pusher at the time of insertion; the driving arm is set to be in a sinking mode, so that the interference between the plug and the socket of the connector and the influence on the plug and the socket caused by the interference between the driving arm or the hinge shaft on the driving arm and the plug or the socket of the connector when the plug and the socket of the connector are plugged is avoided.

Furthermore, the protective door comprises two door plates which are symmetrically arranged, and two driving arms are hinged with the same sliding block; set up two door plants of symmetry with the guard gate, through two door plants to run from opposite directions or to closing the opening or closing that realize the guard gate, set up two door plants and compare with a door plant and start to make the stroke shorter, can realize opening fast or closing of guard gate, link to each other two door plants of symmetry and same slider, guarantee that two door plants can synchronous movement, corresponding slider also can make less size.

Further, the protective door also comprises an elastic piece for applying acting force to the door panel to move towards the closed state; the elastic piece is arranged, so that the door plate can be automatically closed when the plug and the socket are separated, the door plate does not need to be manually closed, and the connector is more convenient to use.

Furthermore, the elastic piece is a spring connected between the door plates, and when the protective door is in a closed state, the spring is in a stretching state, so that the spring has a certain pretightening force to ensure that the door plates can be completely closed; select the spring as the elastic component, simple structure sets up conveniently, and the spring still has certain pretightning force when the guard gate is closed, guarantees that the guard gate can be closed completely and prevents that the guard gate mistake from opening.

Furthermore, the pushing piece is provided with an opening position enabling the protective door to be completely opened and a closing position enabling the protective door to be completely closed, and the pushing piece is connected with a resetting device enabling the pushing piece to be restored to the closing position; the reset device is arranged, so that when the plug is separated from the socket, the protective door can be automatically restored to a closed position, and the situation that the protective door cannot be normally closed due to the fact that the pressing rod continuously presses the sliding block after the plug is separated from the socket is avoided.

Furthermore, the pushing piece is a pressing rod, a pressing rod guide seat is arranged on the socket or the plug, a guide hole for guiding the pressing rod is formed in the pressing rod guide seat, a return spring is arranged on one side, through which the pressing rod penetrates, of the guide hole, a baffle is arranged at the end part, away from the guide hole, of the return spring, the end part of the pressing rod is inserted into the return spring and supported on the baffle, and the return spring and the baffle form the return device; the socket or the plug is provided with the pressure bar guide seat to guide the pressure bar, and the reset device is formed by matching the spring and the baffle plate, so that the structure is simple.

Drawings

FIG. 1 is a general schematic view of a first embodiment of a connector device with a protective door according to the present invention;

FIG. 2 is a schematic view of the receptacle and door opener of FIG. 1;

FIG. 3 is a schematic view of the door opening device of FIG. 1;

FIG. 4 is a schematic view of the guard door of FIG. 1;

FIG. 5 is a schematic view of the slider of FIG. 3;

FIG. 6 is a schematic view of the compression bar of FIG. 3;

FIG. 7 is a schematic view of the protection door of FIG. 1 in an open state;

wherein: 1-plug, 2-socket, 3-pressure bar guide seat, 4-protective door, 5-door panel I, 6-door panel II, 7-pressure bar, 8-reset spring, 9-spring, 10-fixed hinge shaft, 11-slide block, 12-slide block inclined plane, 13-pressure bar inclined plane, 14-connecting rod, 15-shielding part and 16-driving arm.

Detailed Description

The connector device with a protective door according to the present invention will be further described with reference to the accompanying drawings.

The first embodiment of the connector device with the protective door of the present invention, as shown in fig. 1, includes a plug 1 and a socket 2, the plugging and unplugging direction of the plug 1 and the socket 2 is defined as the up-down direction, the socket 2 is provided with a protective door 4 for shielding a contact element in the socket 2, the socket 2 is further provided with a press rod guide seat 3 extending outward along the radial direction of the socket 2, the extending direction of the press rod guide seat 3 is defined as the left-right direction, and the protective door 4 is fixed on the press rod guide seat 3.

The connector device in this embodiment further includes a door opening mechanism for controlling the opening of the protective door 4, as shown in fig. 2 and 3, the door opening mechanism includes a pushing member capable of displacing in the up-down direction, and further includes a slider 11 placed on the pressure lever guide base 3, the slider 11 is limited by a horizontal guide rail pre-arranged on the pressure lever guide base 3 in the left-right direction, and can only displace in the horizontal direction with respect to the pressure lever guide base 3, and the slider 11 has a slider inclined surface 12 facing the pushing member as shown in fig. 5; the slider ramp 12 extends from top to bottom, left to right.

The pushing member in this embodiment is a pressing rod 7, a guide hole for the pressing rod 7 to pass through is formed in the pressing rod guide seat 3, the pressing rod 7 is matched with the hole wall of the guide hole, so that the pressing rod 7 can only move in the vertical direction relative to the pressing rod guide seat 3, and the pressing rod 7 is guided in the vertical direction, the lower portion of the pressing rod 7 is provided with a pressing rod inclined surface 13 as shown in fig. 6, the pressing rod inclined surface 13 extends from top to bottom and from left to right, and the inclined angle of the pressing rod inclined surface 13 is equal to that of the sliding block inclined surface 12 to form inclined surface matching. Because the plug 1 and the socket 2 are inserted and combined in the vertical direction, the plug 1 is provided with a jacking part which can directly jack the pressure rod 7 to enable the pressure rod 7 to generate downward displacement, and when the pressure rod 7 generates downward displacement, the slider inclined plane 12 is pushed through the pressure rod inclined plane 13, so that the slider 11 is pushed to generate leftward displacement, and the downward displacement of the pressure rod 7 is converted into leftward displacement of the slider 11. The lower part of the pressure lever 7 is also provided with a convex block for limiting the pressure lever, and the convex block is used for being matched with a hole at the lower end of a guide hole on the pressure lever guide seat 3 for the pressure lever 7 to pass through along a stop, so that the pressure lever 7 is prevented from being separated upwards from the guide hole.

As shown in fig. 2, 3 and 4, the protective door 4 is composed of a first door panel 5 and a second door panel 6 which are symmetrically arranged, the first door panel 5 and the second door panel 6 are oppositely combined to form the circular protective door 4, the first door panel 5 and the second door panel 6 are symmetrically arranged, and both the first door panel 5 and the second door panel 6 are provided with a shielding part 15 for shielding the socket 2 and a driving arm 16 for driving the shielding part 15 to displace; the driving arm 16 of the first door panel 5 is crossed with the driving arm 16 of the second door panel 6, the first door panel 5 and the second door panel 6 are hinged at the crossing position of the two driving arms 16 through a fixed hinge shaft 10, and the fixed hinge shaft 10 is fixed on the compression bar guide seat 3, namely, the first door panel 5 and the second door panel 6 are hinged together through the fixed hinge shaft 10 and are fixed on the compression bar guide seat 3 through the fixed hinge shaft 10.

One end, far away from the door plate 5, of the driving arm 16 of the door plate 5 is hinged with a connecting rod 14, and the right end of the connecting rod 14 is hinged and fixed with the sliding block 11; correspondingly, one end of the driving arm 16 of the second door panel 6, which is far away from the second door panel 6, is also hinged with a connecting rod, and the right end of the connecting rod is hinged and fixed with the sliding block 11; when the pressing rod 7 pushes the sliding block 11 to move leftwards, the first door panel 5 and the second door panel 6 are fixed on the pressing rod guide seat 3 through the fixed hinge shaft 10, so that leftward movement cannot occur, and only rotation can be performed around the axis of the fixed hinge shaft 10, the first door panel 5 and the second door panel 6 rotate around the axis of the fixed hinge shaft 10 to open the protective door 4, and at the moment, the plug 1 can be plugged with the socket 2. The movement of the plug 1 and the socket 2 in the up-down direction is converted into the rotation of the first door plate 5 and the second door plate 6, so that the protection door 4 is opened. The first door plate 5 and the second door plate 6 are connected with one sliding block 11 through connecting rods, so that the first door plate 5 and the second door plate 6 can move synchronously, and the equal stroke of the first door plate 5 and the second door plate 6 is ensured.

The axis of fixed hinge 10 is arranged along upper and lower direction, door plant one 5 and door plant two 6 can take place the translation around the axis of fixed hinge 10, take place the upset with guard gate among the prior art around articulated axis and compare, can not cause too big air current disturbance, the translation is compared with the upset, the action stroke is short, the opening time of connector has been shortened, pin joint between door plant one 5 and the door plant two 6 is in between the articulated axis of shielding part 15 and connecting rod 14 and actuating arm 16, the stroke that makes the door plant is shorter, it is quicker to move, the opening time of guard gate 4 has been shortened, the barrier propterty of connector has been improved. The link is provided on the left side of the slider 11, and the size of the link and the driving arm 16 can be effectively shortened as compared with the case where the link is provided on the right side of the slider, thereby enabling the connector device to have a smaller size.

The driving arm 16 of the first door panel 5 is depressed with respect to the shielding portion 15, and like the first door panel 5, the driving arm 16 of the second door panel 6 is also depressed with respect to the shielding portion 15. The driving arm 16 is arranged in a sinking mode, so that the plug 1 is avoided, and the problem that the protection performance of the connector is influenced because the plug 1 and the socket 2 cannot be completely plugged due to the driving arm 16 when the plug 1 and the socket 2 are plugged is avoided. At the same time, the structure of the connector device can be made more compact.

When the pressure lever 7 moves downwards, when the protective door 4 is completely opened, the position of the pressure lever 7 is an opening position, and when the corresponding pressure lever 7 moves upwards to completely close the protective door 4, the position of the pressure lever 7 is a closing position. A reset device is further installed below the guide hole of the pressure rod guide seat 3, the reset device can enable the pressure rod 7 to automatically return to a closed position, and the situation that the pressure rod 7 continuously pushes the sliding block 11 after the plug 1 and the socket 2 are separated is avoided, so that the protective door 4 cannot be normally closed. The resetting means in this embodiment is reset spring 8, reset spring 8 is coil spring, for hollow structure confession depression bar 7 in the middle of reset spring 8 inserts, reset spring 8's lower extreme is provided with the baffle, support on the baffle when depression bar 7 inserts in

reset spring

8, 1 roof pressure depression bar 7 of plug downwards takes place the displacement, reset spring 8 is stretched, after plug 1 and socket 2 separation, reset spring 8 drives depression bar 7 rebound, lose the roof pressure effect to slider 11, guard gate 4 just also can be smooth closing.

The right-hand member of door plant one 5 and door plant two 6 still connects through the elastic component, fixed elastic component is spring 9 in this embodiment, spring 9 is in tensile state when door plant one 5 and door plant two 6 are closed, can carry out the tractive to door plant one 5 and door plant two 6, guarantee the tightness between door plant one 5 and the door plant two 6, simultaneously because the existence of spring 9, when plug 1 and socket 2 separation, door plant one 5 and door plant two 6 self-closing under the effect of spring 9, this time spring 9 still has certain pretightning force and prevents that protective door 4 from opening by mistake.

In the first embodiment of the invention, when the plug is plugged, the pressing part on the plug 1 directly presses the pressing rod 7, so that the pressing rod 7 moves downwards and pushes the sliding block 11 to displace leftwards, the connecting rod hinged with the sliding block 11 pushes the door panel I5 and the door panel II 6 to rotate around the fixed hinge shaft 10, and the protective door 4 is opened, as shown in fig. 7; when the connector is separated, the plug 1 is separated from the socket 2, the jacking effect on the pressure lever 7 is lost, the pressure lever 7 moves upwards under the action of the return spring 8, and the door panel I5 and the door panel II 6 are quickly closed under the action of the spring 9; in the opening and closing process, the first door plate 5 and the second door plate 6 rotate, the stroke is short, too large air flow disturbance cannot occur, and the protection performance of the connector is improved.

The second embodiment of the present invention is different from the first embodiment in that: the protective door is arranged on the plug, and the opening device is arranged on the socket.

The third embodiment of the present invention is different from the first embodiment in that: in the first embodiment, the pushing member for pushing the sliding block is a rod body, and in the first embodiment, the pushing member is a pushing plate fixed on the plug. In other embodiments, the pushing member may be a protrusion having a slope structure.

The link mechanism for opening and closing the door panel in the above embodiment is a slider-crank mechanism, and the link in the slider-crank mechanism is connected to the driving arm 16 of the door panel, and the driving arm 16 is arranged in a cross manner. In other embodiments, the link mechanism may be replaced with other forms as long as the guiding motion of the slider can be converted into the rotation of the door panel, and then the door panel can be opened and closed, and the specific form of the link mechanism can be realized by those skilled in the art without creative work according to needs. For example, the link 14 in fig. 4 is fixed to the slider 11, a slide groove extending in the longitudinal direction of the drive arm 16 is provided at the distal end of the drive arm 16, and the distal end of the link is connected to the drive arm 16 by a pivot pin guided in engagement with the slide groove to constitute a tangent mechanism, whereby the slider can drive the door panel. As another example, the driving arms 16 of the two door panels in fig. 4 are set to extend obliquely in the up-down direction of fig. 4, the two corresponding connecting rods are arranged in a v shape, the opening of the v shape faces the driving arms 16, and at the same time, the pressing rod is set to the left side of the sliding block in fig. 4, so that the inclined surface of the sliding block faces the shielding part 15, and the inclined surface of the pressing rod faces away from the shielding part 15; when the door opening device is used, the sliding block moves away from the door plate when the sliding block is pushed by the pressing rod, and the two driving arms 16 are driven to mutually approach through the connecting rod, so that the door plates are opened relatively. For another example, in the case where the inclined surface of the slider faces the shielding portion 15, and the inclined surface of the pressing rod faces away from the shielding portion 15, that is, the slider moves leftward when the connector is plugged, the connecting rod 14 in fig. 4 may be configured to extend in the up-down direction in fig. 4 and be fixed to the slider 11, a sliding slot extending in the up-down direction in fig. 4 is provided on the connecting rod 14, and the end of the driving arm 16 is connected to the connecting rod through a rotating pin in guiding fit with the sliding slot to form a sine mechanism, so that the driving of the door panel by the slider can be realized.

The fourth embodiment of the present invention is different from the first embodiment in that: the driving arms 16 of the first and second panels may be flush with the shielding part 15. In other embodiments, the drive arm 16 may also be located above the shield portion 15, in which case a recess may be provided in the plug to accommodate the drive arm 16.

The fifth embodiment of the present invention is different from the first embodiment in that: the guard gate only forms by an solitary door plant, for example makes door plant 5 in the figure 4 and door plant two 6 as an organic wholely, saves actuating arm on former door plant two 6 and the connecting rod of being connected with the actuating arm, through the opening and close of actuating arm and the corresponding connecting rod drive integral type door plant on former door plant 5, of course, should suitably increase actuating arm 16's swing stroke this moment.

The sixth embodiment of the present invention is different from the first embodiment in that: the elastic part is a torsion spring arranged on a hinge shaft of the first door panel and the second door panel. In other embodiments, the elastic member may also be a coil spring disposed between the first door panel driving arm and the second door panel driving arm.

The seventh embodiment of the present invention is different from the first embodiment in that: the pressure bar guide seat and the socket are arranged in a split manner.

Claims

1. Connector device with guard gate, including plug, socket, setting guard gate between plug and socket and be used for driving the mechanism of opening that guard gate opened, its characterized in that: the door opening mechanism comprises a pushing piece arranged along the plugging direction of the connector in a guiding mode and a sliding block arranged perpendicular to the plugging direction of the connector in a guiding mode, the pushing piece and the sliding block are matched through an inclined matching surface to convert the guiding motion of the pushing piece into the guiding motion of the sliding block, the protective door is a hinged door plate, the hinge axis of the door plate is parallel to the plugging direction of the connector, the door plate is connected with the sliding block in a connecting rod mechanism mode, and the connecting rod mechanism is used for converting the guiding motion of the sliding block into the rotation of the door plate to achieve the opening and closing of the door plate; the connecting rod mechanism is a crank sliding block mechanism; the two door plates are mutually butted when being closed; each door plate comprises a shielding part and a driving arm, the driving arms of the two door plates are arranged in a crossed manner, and a hinge shaft of each door plate is positioned at the crossed point of the driving arms; and a connecting rod is arranged between the tail end of the driving arm and the sliding block, two ends of the connecting rod are respectively hinged with the driving arm and the sliding block, and the connecting rod, the driving arm and the sliding block form a crank sliding block mechanism taking the driving arm as a crank.

2. The connector device with the protective door according to claim 1, wherein: the hinge shaft of the door panel is located on the side of the driving arm near the connecting rod for driving the movement of the shielding part in the form of a laborious lever.

3. The connector device with the protective door according to claim 1, wherein: the driving arm is depressed relative to the shielding portion in a moving direction of the pusher at the time of insertion.

4. The connector device with the protective door according to claim 1, wherein: the protective door comprises two door plates which are symmetrically arranged, and two driving arms are hinged with the same sliding block.

5. The connector device with the protective door according to any one of claims 1 to 4, wherein: the protective door further includes an elastic member for applying a force to the door panel to move toward the closed state.

6. The connector device with the protective door according to claim 5, wherein: the elastic piece is a spring connected between the door plates, and when the protective door is in a closed state, the spring is in a stretching state, so that the spring has certain pretightening force to ensure that the door plates can be completely closed.

7. The connector device with the protective door according to any one of claims 1 to 4, wherein: the pushing piece is provided with an opening position enabling the protective door to be completely opened and a closing position enabling the protective door to be completely closed, and the pushing piece is connected with a resetting device enabling the pushing piece to be capable of being restored to the closing position.

8. The connector device with the protective door according to claim 7, wherein: the pushing piece is a pressing rod, a pressing rod guide seat is arranged on the socket or the plug, a guide hole for guiding the pressing rod is formed in the pressing rod guide seat, a return spring is arranged on one side, through which the pressing rod penetrates, of the guide hole, a baffle is arranged at the end, away from one end of the guide hole, of the return spring, the end of the pressing rod is inserted into the return spring and supported on the baffle, and the return spring and the baffle form the resetting device.