CN205036851U - Elastic potential energy driven start -stop mechanism of reciprocating - Google Patents

Abstract

The utility model relates to a reciprocating start-stop mechanism driven by elastic potential energy. Two shift fork rods are arranged on the shift rod, and the two shift fork rods are respectively located outside the two ends of the drive gear; one end of the drive shaft is provided with a screw rod, and the screw sleeve threaded to connect the bent rod is sleeved on the screw rod; The first rotating shaft, the second rotating shaft and the third rotating shaft, the swing rod is connected to the lever through the first rotating shaft, the swing rod is connected to the chain rod through the second rotating shaft, and the swing rod is rotated through the third rotating shaft; the two ends of the chain are respectively connected to the free end of the chain rod and The free end of the curved rod, the free end of the chain rod and the free end of the curved rod can be pushed together; one end of the first spring is fixedly connected to the swing rod at the second rotating shaft, and the other end of the first spring is fixedly connected to the fixed block superior. A bump is also arranged on the driving lever, and the bump is connected with the stop mechanism.

Description

Reciprocating start-stop mechanism driven by elastic potential energy

technical field

The utility model relates to a transmission conversion mechanism, in particular to a reciprocating start-stop mechanism driven by elastic potential energy.

Background technique

The transmission conversion mode of modern power mechanism is mostly carried out by means of frequency converter to control the motor. The frequency converter controls the speed of the motor and controls the steering of the motor, which makes the speed output of the motor to the transmission mechanism extremely flexible. However, the common frequency converter has insufficient voltage compensation for the motor when outputting low frequency, and the torque boost of the motor is not enough, resulting in a decrease in the output torque of the motor and unstable load capacity. Therefore, in the case of low-speed operation and high power requirements, it is still necessary to use a reducer. When the power output by the motor is decelerated by the reducer, the torque can be increased. However, in the case of frequent cut-off of output power and frequent reversing, this type of device can only be realized by frequent start and stop of the motor, and frequent forward and reverse switching. Long-term use is not conducive to the normal operation of the motor. Therefore, it is necessary to design a set of mechanical transmission mechanism to realize the functions of frequent reversing and frequent cut-off of the output power under the condition of continuous and stable operation of the motor and reducer.

Contents of the invention

The utility model overcomes the disadvantages of the prior art and provides a reciprocating start-stop mechanism driven by a spring swing bar and driven by elastic potential energy assisted by a chain.

In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a reciprocating start-stop mechanism driven by elastic potential energy, including: a driving mechanism and a toggle mechanism connected by a shift fork lever, which is characterized in that,

- the drive mechanism can drive the drive gear to rotate forward and reverse;

- the toggling mechanism includes a slidably set lever, on which two fork levers are arranged, and the two fork levers are respectively located outside the two ends of the driving gear;

One end of the drive shaft is provided with a screw rod, and the screw sleeve connecting the bent rod is threaded on the screw rod;

The first rotating shaft, the second rotating shaft and the third rotating shaft are arranged in turn on the swing rod, the swing rod is connected to the lever through the first rotating shaft, the swing rod is connected to the chain rod through the second rotating shaft, and the swing rod is rotated through the third rotating shaft; the two ends of the chain are respectively connected The free end of the chain rod and the free end of the curved rod, the free end of the chain rod and the free end of the curved rod can be pushed together; one end of the first spring is fixedly connected to the swing rod at the second rotating shaft The other end of the first spring is fixedly connected to the fixed block.

A bump is also provided on the shift lever, and the bump is engaged with the stop mechanism.

In a preferred embodiment of the present invention,

- when the driving gear meshes with the first gear, the swing bar is biased towards the first gear, and the first spring is located on one side of the swing bar's offset direction;

- When the driving gear meshes with the second gear, the swing bar is biased toward the second gear, and the first spring is located at one side of the swing bar's biasing direction.

In a preferred embodiment of the present invention, the first spring is in a stretched state.

In a preferred embodiment of the present invention,

- when the driving gear meshes with the first gear, the screw drives the screw sleeve away from the driving gear, and the chain is in a tight state;

- When the driving gear meshes with the second gear, the screw drives the screw sleeve close to the driving gear, the chain is in a relaxed state, and the free end of the chain rod and the free end of the curved rod are pushed together .

In a preferred embodiment of the present invention, the distance between the two shift fork rods is greater than the axial length of the driving gear.

In a preferred embodiment of the utility model, a stopper is provided on both sides of the free end of the swing rod.

In a preferred embodiment of the present invention, the two ends of the driving rod are respectively slidably socketed on the corresponding sleeves.

In a preferred embodiment of the present invention, the driving gear sliding key is arranged on the driving shaft, and the moving distance of the driving gear on the sliding key of the driving shaft is the distance between the first gear and the second gear axial distance.

In a preferred embodiment of the present invention, the driving mechanism includes a first gear and a second gear that can respectively mesh with the driving gear, the driving gear is slidably arranged on the driving shaft, the first gear and the second gear The two gears rotate in opposite directions;

The first gear is coaxially connected with a transmission gear, and the transmission gear meshes with the second gear.

In a preferred embodiment of the present invention, the stop mechanism includes a stop rod with a wedge-shaped head at one end and a fixed plate, the wedge-shaped head of the stop rod protrudes outside one surface of the fixed plate, and the stop rod also One end of the second first spring protrudes outside the other surface of the fixed plate, and the two ends of the second first spring are respectively fixed on the fixed plate and the stop bar; the wedge-shaped head includes a wedge-shaped surface and a right-angled surface parallel to the gear rod axis.

In a preferred embodiment of the present invention, a handle is provided at the end of the stop rod on the stop mechanism.

The defect that exists in the operation, the utility model has the following beneficial effects:

(1) Through the action of the toggle mechanism, the position of the driving gear can be changed between the first gear and the second gear, which plays the role of changing the meshing object of the driving gear. At the same time, because the first gear and the second gear rotate in opposite directions, Ensure that the drive shaft changes direction of rotation each time the drive gear changes meshing objects.

(2) The rotation direction of the drive shaft and the toggle direction of the toggle mechanism just form a linkage structure. When the drive gear meshes with the first gear, the toggle mechanism is driven by the drive shaft so that the toggle mechanism has the ability to turn the drive gear to the second gear. The tendency and power of the gear, and finally the driving gear is separated from the first gear, and driven by the elastic potential energy of the first spring on the swing rod to mesh with the second gear; otherwise, when the driving gear meshes with the second gear, the toggle mechanism will make the driving gear reverse movement.

(3) On the one hand, the structure of the feather key can ensure that there is a clamp limit between the drive gear and the drive shaft along the circumference of the drive shaft, so that the drive gear will not move relative to the drive shaft along the circumference; on the other hand, the drive gear can Sliding along the axial direction of the drive shaft ensures that the drive gear moves between the first gear and the second gear.

(4) The two fork levers are respectively located on both sides of the drive gear, and the drive gear can move axially along the drive shaft under the drive of the lever.

(5) The set block can limit the movement posture of the lever, and at the same time, the stopper can limit the swing lever driven by the first spring within a certain swing range, and then the movement range of the lever is also limited to ensure that the lever will not be excessive The left and right offsets only ensure the distance between the first gear and the second gear for the drive gear to change mesh.

(6) When the driving gear meshes with the first gear, the pendulum shifts toward the side of the first gear. At this time, the first spring tightens the pendulum, and the screw sleeve is driven away from the first gear by the screw rod, and then the chain is tightened, and then Pull the swing bar to rotate towards the second gear side, and when the swing bar crosses the vertical state, the driving gear will disengage from the first gear, at this time, the pulling force of the first spring will pull the swing bar towards the second gear side, and Swing the pendulum toward the second gear, and finally press the drive gear to mesh with the second gear.

(7) During the left and right movement of the fork lever, the two fork levers continuously push the drive gear to move left and right along the drive shaft to change the meshing objects.

(8) The first rotating shaft, the second rotating shaft and the third rotating shaft cooperate with each other, so that the pendulum can rotate with the third rotating shaft as the center of a circle, drive the shift lever to move left and right, and then drive the fork lever to follow the shift lever to move left and right.

(9) The structure of the chain can ensure that when the screw sleeve is far away from the first gear, the chain is tightened, and the chain increases the total length of the chain rod and the bent rod; when the screw sleeve is close to the first gear, the chain is loose, and the end of the bent rod and the chain rod The ends are topped together, and the total length does not include the length of the chain at this time.

(10) Through the set soft connection, it is ensured that during the reciprocating movement of the screw sleeve, when the swing rod is pushed, the distance between the screw sleeve and the swing rod will change due to the change of the chain, so that for the auxiliary lever Push the position change of the driving gear and the meshing object transformation.

(11) The setting of the stopper ensures that the lower end of the swing rod will not deviate beyond the range, that is, the swing rod will not make the moving range of the lever too large.

(12) The structure of the screw driving the screw sleeve, and then the screw sleeve provides the power source for the toggle mechanism. Since the rotation direction of the screw is related to the meshing object of the drive gear, the movement direction of the screw sleeve is related to the rotation direction of the drive shaft, and The direction of rotation of the drive shaft is controlled by the toggle mechanism; thus, the above-mentioned process forms a cyclic motion process that influences each other, and the toggle mechanism and the drive mechanism continuously affect the continuous cycle control.

(13) The distance between the two shift fork rods is greater than the axial length of the drive gear, which can provide inertial buffering for the reverse movement of the drive gear.

(14) The distance between the two shift fork rods is greater than the axial length of the drive gear, and the length longer than the gear is the margin of the distance between the two shift fork rods relative to the length of the drive gear. Due to the existence of the above margin, the swing rod is in the When in the vertical state, the two shift fork rods will not be blocked by the drive gear, and the swing rod only needs to rely on inertia when it crosses its vertical state.

(15) The transmission gear is coaxial with the first gear, and the second gear meshes with the transmission gear to realize the reverse rotation of the first gear and the second gear.

(16) The handle can pull up the stop lever on the stop mechanism, so that the bump blocked by the right-angled surface on the stop mechanism can be released from the restraint, and the lever can continue to move left and right. As long as the mechanism is not pulled up, it can only do single Periodic movement.

(17) The position of the stop mechanism can block the projection at the position where the drive gear is just between the first gear and the second gear, and the drive gear is disengaged at this time.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Fig. 1 is a three-dimensional structure diagram one of a preferred embodiment of the present utility model;

Fig. 2 is the three-dimensional structure diagram two of the preferred embodiment of the present utility model;

Fig. 3 is a three-dimensional structure diagram of the stop mechanism of the present utility model;

In the figure: 1, the first gear, 2, the second gear, 3, the driving gear, 4, the driving shaft, 5, the feather key, 6, the transmission gear, 7, the driving lever, 8, the fork lever, 9, the cover block , 10, screw rod, 11, screw sleeve, 12, bent rod, 13, chain, 14, chain rod, 15, swing rod, 16, first rotating shaft, 17, second rotating shaft, 18, third rotating shaft, 19, the first One spring, 20, block, 21, fixed block, 22, stop mechanism, 23, stop lever, 24, second spring, 25, wedge-shaped head, 26, wedge-shaped surface, 27, right-angled surface, 28, bump, 29 , handle, 30, fixed plate, 31, bolt locking device.

detailed description

The utility model is described in further detail now in conjunction with accompanying drawing and embodiment, and these accompanying drawings all are simplified schematic diagrams, only illustrate the basic structure of the utility model in schematic mode, so it only shows the formation relevant to the utility model.

As shown in Figure 1, Figure 2 and Figure 3, a reciprocating start-stop mechanism driven by elastic potential energy includes: a driving mechanism and a toggle mechanism connected by a shift fork lever 8,

The drive mechanism includes a drive gear 3 that can mesh with the first gear 1 and the second gear 2 respectively, the drive gear 3 is slidably arranged on the drive shaft 4, and the rotation direction of the first gear 1 and the second gear 2 is opposite; the toggle mechanism includes a slide The shift lever 7 provided, two shift fork levers 8 are arranged on the shift lever 7, and the two shift fork levers 8 are respectively located at the outer sides of the two ends of the driving gear 3; Driven by the driving rod 7, it moves axially along the drive shaft 4.

One end of the drive shaft 4 is provided with a screw rod 10, and the screw sleeve 11 connected to the bent rod 12 is threaded on the screw rod 10; the screw rod 10 drives the structure of the screw sleeve 11, and then the screw sleeve 11 provides a power source for the toggle mechanism. The direction of rotation is related to the meshing object of the drive gear 3, so the direction of motion of the screw sleeve 11 is related to the direction of rotation of the drive shaft 4, and the direction of rotation of the drive shaft 4 is controlled by the toggle mechanism; During the cycle movement process, the toggle mechanism and the drive mechanism continuously affect the continuous cycle control.

The first rotating shaft 16, the second rotating shaft 17 and the third rotating shaft 18 are successively arranged on the swing rod 15, the swing rod 15 is connected to the shift lever 7 through the first rotating shaft 16, the swing rod 15 is connected to the chain rod 14 through the second rotating shaft 17, and the swing rod 15 Rotate through the third shaft 18; the two ends of the chain 13 are respectively connected to the free end of the chain bar 14 and the free end of the bent bar 12, and the free end of the chain bar 14 and the free end of the bent bar 12 can be pushed together; the first spring 19 One end of the first spring 19 is fixedly connected to the swing rod 15 at the second rotating shaft 17 , and the other end of the first spring 19 is fixedly connected to the fixed block 21 . The first rotating shaft 16, the second rotating shaft 17 and the third rotating shaft 18 cooperate with each other, so that the swing rod 15 can rotate with the third rotating shaft 18 as the center of a circle, and drive the shift lever 7 to move left and right, and then drive the shift fork rod 8 to follow the shift rod 7 to move left and right .

Through the action of the toggle mechanism, the position of the driving gear 3 can be changed between the first gear 1 and the second gear 2, which plays the role of changing the meshing object of the driving gear 3. At the same time, due to the rotation of the first gear 1 and the second gear 2 The direction is opposite to ensure that the drive shaft 4 changes the direction of rotation each time the drive gear 3 changes the meshing object.

The rotation direction of the drive shaft 4 and the toggle direction of the toggle mechanism just form a linkage structure. When the drive gear 3 meshes with the first gear 1, the toggle mechanism is driven by the drive shaft 4 so that the toggle mechanism has the ability to turn the drive gear 3 to The inclination and power of the second gear 2, and finally the drive gear 3 breaks away from the first gear 1, and is driven by the elastic potential energy of the first spring 19 on the fork 15 to mesh with the second gear 2; otherwise the drive gear 3 and the second gear 2 When engaged, the toggle mechanism will cause the drive gear 3 to move in reverse.

During the left and right movement of the shift lever 7, the shift fork lever 8 continuously pushes the drive gear 3 to move left and right along the drive shaft 4 through the two shift fork levers 8 to change the meshing object.

The structure of the chain 13 can ensure that when the screw sleeve 11 is away from the first gear 1, the chain 13 is tightened, and the chain 13 increases the total length of the chain bar 14 and the bent bar 12; when the screw sleeve 11 is close to the first gear 1, the chain 13 is loose, The ends of the bent bar 12 and the chain bar 14 are butted together, and the total length does not include the length of the chain 13 at this time.

Through the flexible connection provided, it is ensured that during the reciprocating movement of the screw sleeve 11, when the swing rod 15 is pushed, the distance between the screw sleeve 11 and the swing rod 15 will change the length of a chain 13 due to the change of the chain 13, so for The auxiliary lever 7 promotes the position change of the driving gear 3 and the transformation of the meshing object.

- When the driving gear 3 meshes with the first gear 1, the swing lever 15 is biased towards the direction of the first gear 1, and the first spring 19 is located on one side of the swing lever 15 in the direction of deviation;

- When the driving gear 3 meshes with the second gear 2 , the pendulum 15 is biased toward the second gear 2 , and the first spring 19 is located on one side of the pendulum 15 in the direction of deviation.

The first spring 19 is in tension.

When the driving gear 3 meshes with the first gear 1, the screw 10 drives the nut 11 away from the driving gear 3, and the chain 13 is in a tight state; when the driving gear 3 meshes with the second gear 2, the screw 10 drives the nut 11 to approach the driving gear 3 , the chain 13 is in a relaxed state, and the free end of the chain bar 14 and the free end of the bent bar 12 are abutted against each other. When the driving gear 3 is meshed with the first gear 1, the swing bar 15 is shifted towards the first gear 1 side, at this moment, the first spring 19 tightens the swing bar 15, and the screw sleeve 11 is driven away from the first gear 1 by the screw rod 10, and then The chain 13 is tightened, and then the swing lever 15 is pulled to rotate toward the second gear 2. When the swing lever 15 crosses the vertical state, the drive gear 3 is disengaged from the first gear 1, and the pulling force of the first spring 19 will be Pull the swing lever 15 toward the second gear 2 , and swing the swing lever 15 toward the second gear 2 , and finally press the drive gear 3 to mesh with the second gear 2 .

The distance between the two shift fork rods 8 is greater than the axial length of the drive gear 3 , which can provide inertial buffering for the reverse movement of the drive gear 3 . The distance between the two shift fork rods 8 is greater than the axial length of the drive gear 3, and the length longer than the drive gear 3 is the margin of the distance between the two shift fork rods 8 relative to the length of the drive gear 3. Due to the existence of the above margin, the pendulum When the bar 15 was in the vertical state, the two shift fork rods 8 would not be blocked by the drive gear 3, and the fork 15 only needed to rely on inertia when it crossed its vertical state.

Fork 15 free ends both sides are respectively provided with a stopper 20, and the setting of stopper 20 guarantees that the lower end of fork 15 can not deviate beyond the range, that is fork 15 can not make driving lever 7 move too much.

The two ends of the driving rod 7 are respectively slidably socketed on the respective corresponding sets of blocks 9, the sets of blocks 9 can limit the movement posture of the driving rod 7, and the stopper 20 can limit the swing rod 15 driven by the first spring 19 to a certain swing. Within the range, and then the range of movement of the driving rod 7 is also limited, so as to ensure that the driving rod 7 will not deviate excessively left and right, and only ensure that the driving gear 3 changes the meshing distance between the first gear 1 and the second gear 2.

The sliding key 5 of the driving gear 3 is arranged on the driving shaft 4 , and the moving distance of the driving gear 3 on the sliding key 5 of the driving shaft 4 is the axial distance between the first gear 1 and the second gear 2 . On the one hand, the structure of the feather key 5 can ensure that there is a clamp limit between the drive gear 3 and the drive shaft 4 along the circumference of the drive shaft 4, so that the drive gear 3 will not move relative to the drive shaft 4 along the circumference; The driving gear 3 can slide along the axial direction of the driving shaft 4 to ensure that the driving gear 3 moves between the first gear 1 and the second gear 2 .

The first gear 1 is coaxially connected to the transmission gear 6, the transmission gear 6 meshes with the second gear 2, the transmission gear 6 is coaxial with the first gear 1, and the second gear 2 meshes with the transmission gear 6, realizing the first gear 1 and the second gear The reverse rotation of the second gear 2.

The end of stop bar 23 on stop mechanism 22 is provided with handle, and handle 30 can pull up stop bar 23 on stop mechanism 22, and the projection 28 that is blocked by right-angled surface 27 on stop mechanism 22 can break away from restraint like this, driving lever 7 just can continue to move left and right, as long as do not pull up this mechanism just can only do single cycle motion. The position of the stop mechanism 22 can block the protrusion 28 at the position where the driving gear 3 is just located between the first gear 1 and the second gear 2 , and the driving gear 3 is disengaged at this time.

Stop mechanism 22 comprises a stop bar 23 and a fixed plate 30 that one end has wedge-shaped head 25, and fixed plate 30 is connected with a sleeve block 9, and the wedge-shaped head 25 of stop bar 23 stretches out fixed plate 30 one face outsides, and stop bar 23 other One end of the second spring 24 protrudes from the outside of the other surface of the fixing plate 30 . The two ends of the second spring 24 are respectively fixed on the fixing plate 30 and the stop bar 23 .

As shown in Figure 1, the projection 28 can only cross the wedge-shaped surface 26 on the stop mechanism 22 from the left side of the stop mechanism 22 to the right side of the stop mechanism 22, but the projection 28 cannot cross the stop mechanism from the right side of the stop mechanism 22. Right-angled surface 27 on 22 reaches the left side of stop mechanism 22.

The curved rod 12 is provided with a bolt locking device 31 at its corner, and the part of the curved rod 12 parallel to the drive shaft 4 can be inserted into the inner hole of the bolt locking device 31 and slide in the inner hole. The bolt locking device 31 The bolts on the top are screwed in and screwed out to control the tightness; by adjusting the relative position of the bent rod 12 and the bolt locking device 31, the position adjustment of the bent rod 12 to the shift fork rod 8 can be realized, so as to adjust the shifting of the shift fork rod 8 to the driving gear. timing.

The driving rod 7 can only move along the axial direction of the driving rod 7 itself under the restriction of the cover block 9, but the driving rod 7 cannot rotate along the axial direction of the driving rod itself in the cover block 9, so that the movement on the driving rod 7 is ensured. The shift fork lever 8 can not turn to, and it has also ensured that the shift fork lever 8 can be moved to the drive gear 3 on its motion track.

The above is inspired by the ideal embodiment of the utility model, and through the above description, relevant personnel can make various changes and modifications within the scope of not deviating from the technical idea of the utility model. The technical scope of this utility model is not limited to the content in the description, and must be determined according to the scope of the claims.

Claims (10)

1. a reciprocal start-stop mechanism for elastic potential energy driving, comprising: the driving mechanism be connected by shifting fork bar and toggle mechanism, be is characterized in that,

-described driving mechanism comprises the first gear and the second gear, and described driving mechanism can drive actuation gear to rotate and reverse;

-described toggle mechanism comprises the driving lever sliding and arrange, and described driving lever is arranged two shifting fork bars, two shifting fork bars lay respectively at outside the two ends of described actuation gear;

Described live axle one end is provided with screw rod, and the swivel nut thread bush connecting knee is connected on described screw rod;

Fork sets gradually the first rotating shaft, the second rotating shaft and the 3rd rotating shaft, fork connects driving lever by the first rotating shaft, and fork is by the second rotating shaft connection chain bar, and fork is rotated by the 3rd rotating shaft; Chain two ends connect the described free end of chain bar and the free end of knee respectively, and the free end of described chain bar and the free end of described knee can to together with withstanding on; One end of first spring is fixedly connected on the fork of the second rotating shaft place, and the first spring the other end is fixedly connected on fixed block;

Described driving lever is also provided with projection, and described projection is connected with shut-down mechanism.

2. the reciprocal start-stop mechanism of elastic potential energy driving according to claim 1, is characterized in that:

When-described actuation gear and described first gears meshing, the described first gear direction of described fork deflection, described first spring is positioned at side, described fork offset direction;

When-described actuation gear and described second gears meshing, the described second gear direction of described fork deflection, described first spring is positioned at side, described fork offset direction.

3. the reciprocal start-stop mechanism of elastic potential energy driving according to claim 2, is characterized in that: described first spring is in extended state.

4. the reciprocal start-stop mechanism of elastic potential energy driving according to claim 1, is characterized in that:

When-described actuation gear and described first gears meshing, described in described bolt rod driving, swivel nut is away from described actuation gear, and described chain is in tensioned state;

When-described actuation gear and described second gears meshing, described in described bolt rod driving, swivel nut is near actuation gear, and described chain is in relaxed state, and described chain bar free end and described knee free end are to together with withstanding on.

5. the reciprocal start-stop mechanism of elastic potential energy driving according to claim 1, is characterized in that: the spacing described in two between shifting fork bar is greater than the axial length of described actuation gear.

6. the reciprocal start-stop mechanism of elastic potential energy driving according to claim 1, is characterized in that: described fork free end both sides are respectively provided with a block.

7. the reciprocal start-stop mechanism of elastic potential energy driving according to claim 1, is characterized in that: described driving lever two ends are slidably socketed respectively on each self-corresponding cover block.

8. the reciprocal start-stop mechanism of elastic potential energy driving according to claim 1; it is characterized in that: described actuation gear feather key is arranged on described live axle, described actuation gear displacement distance on the feather key of live axle be namely described first gear and described second gear shaft to distance.

9. the reciprocal start-stop mechanism of elastic potential energy driving according to claim 8, it is characterized in that: described driving mechanism comprises first gear and the second gear that can engage with actuation gear respectively, described actuation gear is slidably arranged on live axle, and described first gear is contrary with described second gear sense of rotation;

Described first gear coaxial connection for transmission gear, described driving gear and described second gears meshing.

10. the reciprocal start-stop mechanism of elastic potential energy driving according to claim 1, it is characterized in that: described shut-down mechanism comprises one end with the locking lever of sphenocephaly and a fixed plate, the sphenocephaly of described locking lever stretches out outside described fixed plate face, outside another face of stretching out described fixed plate of sheathed the two the first springs of the described locking lever the other end, described the two the first both ends of the spring are separately fixed on described fixed plate and locking lever; Described sphenocephaly comprises a sphenoid surface and a right-angle surface, described right-angle surface and lever axis being parallel.