60results about How to "Change the elasticity" patented technology

The invention provides a power tool, comprising a motor, a shell, and a gear reducing mechanism which is driven by the motor and is arranged in the shell; the gear reducing mechanism comprises an internal tooth ring which can be contained in the shell in a rotatable way; the power tool also comprises a clutch mechanism which comprises a pushing element and an elastic element, and a torque adjusting element; the external surface of the internal tooth ring is provided with at least a concave trough; the pushing element is arranged in any concave trough movably; the elastic element which can be deformable in radial direction is arranged between the pushing element and the torque adjusting mechanism, thus leading the elasticity of the elastic element to be changed by adjusting the torque adjusting element.

A damping-rigidness-controllable double-freedom-degree vibration active control platform comprises a cross-shaped beam frame and a square base which are connected through a flexible hinge. A cross-shaped beam of the cross-shaped beam frame is distributed in the diagonal directions of the square base. A structure column is arranged at the center of the cross-shaped beam frame. Sensors and actuators are connected between the lower portions of the diagonal top ends of the cross-shaped beam frame and the square base respectively. Four limiting columns are arranged between the cross-shaped beam of the cross-shaped beam frame and the square base respectively. Prearranged gaps are reserved between the limiting columns and the cross-shaped beam frame. Four balancing weights are fixed on the lower portion of the cross-shaped beam frame between the sensors or the actuators and the limiting columns respectively. Twisting limiting spring pieces are arranged at the symmetrical positions on the lower portion of the cross-shaped beam frame between the limiting columns and the flexible hinge. The electromagnetic type sensors and the electric-damping electric-rigidness actuators are used to achieve detecting of angular speed and actuating, the flexible hinge and the spring piece with changeable thickness are combined to achieve controllable damping and rigidness in a quantifying mode, and double-freedom-degree vibration active control in the x direction and the y direction of the structure is achieved.

The invention discloses a pavement compaction device capable of changing the compaction direction for civil engineering construction. The pavement compaction device comprises a support transverse plate, wherein a fixing rod frame is arranged at one side of the upper end surface of the support transverse plate; a tube body is arranged at one side of the fixing rod frame; the top end of the tube body is hinged to a top rod of the fixing rod frame; a gear shaft section is arranged at one end of a driving transverse shaft; a driving gear engaged with the gear shaft section is arranged on a drivingmotor main shaft; a rotating gear is arranged on a transmission transverse shaft; a plurality of incomplete gears matched with the rotating gear are arranged on the driving transverse shaft; a coiling wheel is also arranged on the transmission transverse shaft; a pull rope is wound on the coiling wheel; one end of the pull rope bypasses a transition pulley arranged at the top of the fixing rod frame to be connected with a sliding push plate arranged inside the tube body. The pavement compaction device has the advantages that the pavement compaction is convenient; the operation is simple and convenient; the force application intensity can be changed for adapting to different pavements; during the compaction, the structure is stable; the movement is convenient; meanwhile, the inclined pavement can be compacted; the application range is wide; the practicability is higher.

The invention relates to a small-amplitude parallel magnetorheological damper based on two polar plates. Two polar plates on an extension shaft are connected with a spring on an outer ring of a cylinder block through adjusting plates in parallel; and when the polar plates extrude magnetorheological fluid in a cavity through a reciprocating motion, the spring is compressed or elongated to generatedamping force. The adjusting plates can adjust the extension quantity of the spring to change the damping force provided by the spring. A magnetic exciting coil is arranged between the cylinder blockand an isolation cylinder; the current is adjusted to change the magnitude of a magnetic field; and the mode of the magnetorheological fluid is changed to adjust the damping force. The double polar plates and the spring are combined to realize the rigidity and damping adjustment of the damper; and the damper has the characteristics of small size, high damping force and high controllability, and inparticular, is suitable for the field of vibration control with smaller amplitude, such as vibration inhibition in the cutting process.

The invention relates to the field of agricultural planting and particularly discloses a cultivation apparatus of black wax gourd, comprising a cultivation tank, a water-absorbing barrel and a pillar;a water storage cavity is arranged in the pillar; the lower portion of the pillar is provided with a water inlet and a sealed channel; a return spring and a seal plate are arranged in the sealed channel; a water-absorbing piston is arranged in the water-absorbing barrel; the sidewall of the water-absorbing barrel is provided with an exhaust one-way valve and a water-absorbing one-way valve; a partition is arranged in the cultivation tank and is provided with through holes; a plurality of support components are arranged below the partition; each support component includes a support spring anda cylinder, one end of the support spring is fixed to a piston of the cylinder, and the other end of the support spring is abutted to the partition; an inflating tube is fixed to the sidewall of the cultivation tank; an electromagnet is fixed to the cultivation tank; the bottom of the cultivation tank is provided with a switch; after the switch is pressed, the electromagnet is enabled to start operating. The cultivation apparatus of black wax gourd enables plants to be automatically watered during growth.

The present invention discloses a suspension system for a vehicle, which has a roll suppressing device such as a stabilizer device. When determining the target rotation angle θ of the actuator of the roll suppressing device, if the actual lateral G, that is, the lateral acceleration actually generated on the vehicle body, is smaller than the first threshold Gy1 (S19), based on the estimated lateral G, that is, according to Determine the lateral acceleration obtained from the steering angle δ and the vehicle speed v (S20). If the actual lateral G is greater than the second threshold Gy2 (S21), then determine based on the actual lateral G (S18). In addition, if the actual lateral G When it is greater than or equal to the first threshold Gy1 and less than or equal to the second threshold Gy2, it is based on the difference between the value of the actual horizontal G multiplied by the coefficient α that increases linearly from 0 to 1, and the value of the estimated horizontal G multiplied by the coefficient (1-α) and determine (S22). It is thereby possible to prevent control play from occurring while excluding the influence of comparatively small lateral accelerations that are not related to the rotation of the vehicle.

The invention discloses a pediatric clinical special sputum suction device. The pediatric clinical special sputum suction device comprises a sputum suction mechanism, a pressure limiting mechanism, aplaying mechanism and an observation mechanism; the sputum suction mechanism comprises a box body, a sputum suction tube penetrates through the box body, the side surface of the sputum suction tube isprovided with a pressure gauge, the two ends of the sputum suction tube are provided with a sputum suction head and a rubber plug respectively, the rubber plug blocks the mouth of a transparent collection tank, a vacuum pump is disposed on the top side of the interior of the box body, and the vacuum pump penetrates through the rubber plug through an air pipe; the pressure limiting mechanism comprises a fixed sleeve, the side surface of the interior of the fixed sleeve is fixedly connected with an orifice plate, the upper surface of the orifice plate is provided with a spring, and the end, away from the orifice plate, of the spring is provided with a ball plug. By adopting the pediatric clinical special sputum suction device, the internal pressure of the sputum suction tube can be limitedto prevent too high internal pressure of the sputum suction tube and avoid accidental damage to the respiratory tract of a pediatric patient, and the pediatric clinical special sputum suction device is convenient to use.

The invention relates to a bearing testing apparatus capable of applying radial alternating loads. The apparatus comprises a computer, a rotary motor, a rotary shaft, an alternating load loading module and test accompanying bearings, wherein the rotary motor is controlled by the computer, the output shaft of the rotary motor is connected to the rotary shaft through a coupling; a tested sliding bearing sleeves on the rotary shaft; a movable clamp sleeves on the sliding bearing; the test accompanying bearings are arranged on the left and right sides of the sliding bearing; fixed clamps are arranged on the outer sides of the test accompanying bearings to fix and support; the alternating load loading module is arranged on the movable clamp and is composed of four groups of assemblies which aresymmetrical in pairs in four directions. Each of the assemblies comprises a linear motor, a spring and a connecting device. Compared with the prior art, the apparatus can load alternating loads in four direction and two radial directions of the bearing.

The invention provides a medicine roller based on deformation of an elastic element so as to change pressure, and relates to the field of traditional Chinese medicines. The medicine roller based on the deformation of the elastic element so as to change the pressure comprises a grinding wheel and a grinding disc, wherein the two sides of the grinding disc are provided with convex carrying plates; and the opposite surfaces of the two carrying plates are provided with a pressure adjustable linear drive, wherein the linear drive can drive the grinding wheel to work; the pressure adjustable lineardrive is composed of a linear motor, a lifting body capable of moving longitudinally, a first elastic element, a limiting body and an adjusting mechanism, wherein the adjusting mechanism is used for adjusting the height of the limiting body; and the adjusting mechanism is composed of a rack and a one-way limiting wheel. Compared with the prior art, through the arrangement of the carrying plates tocoordinate with the pressure adjustable linear drive, the linear motor in the adjustable linear driving mechanism is used for driving the grinding wheel to move so as to roll the traditional Chinesemedicines, and the pressure of the grinding wheel is adjusted through the adjusting mechanism, so that different degrees of rolling of different medicines can be achieved.

The invention discloses an automobile rubber spring seat comprising an installation base. The inner side of the installation base is connected with installation threaded rods through bearings in a rotating manner. The outer sides of the installation threaded rods are connected with a movement buckle plate through thread engagement. The movement buckle plate is located on the inner side of the installation base. The installation threaded rods penetrate the side wall of the installation base and extend to the outer side of the installation base. Spring fixing hooks are arranged on one side of the movement buckle plate, penetrate one side of the installation base and extend to the outer side of the installation base. A spring is arranged at the tail ends of the spring fixing hooks. An inner sleeve rod is arranged inside the spring. One end of the inner sleeve rod is fixedly connected with one side of the installation base. The automobile rubber spring seat is provided with the threaded rods, a sliding pressing plate and the inner sleeve rod, and the problem that because when the automobile rubber spring seat is used, it is hard to change the initial elastic force of the spring throughthe automobile rubber spring seat, the use effect of the automobile rubber spring seat is influenced is solved.

The invention discloses a small space tether system unfolding brake mechanism adopting a spinning shaft sleeve, and belongs to the technical field of space tether system equipment. The small space tether system unfolding brake mechanism comprises a small instrument cabin, and a spinning brake, a tether spool core, a tether calibration device, a high-strength tether, an unfolding length measurement module and an ejection module which are arranged in the small instrument cabin, the small instrument cabin is fixed on a mother satellite of the space tether system; the spinning brake restrains the axial displacement of the spinning shaft sleeve through the elastic force of a spring in the spinning brake, so that the unfolding motion of the high-strength tether is braked until the speed is zero; the tether spool core is used for winding a tether, and the unfolding length measuring module is used for guiding the tether and measuring the length and the speed of the tether; and the ejection module is used for control and signal processing of the whole mechanism. The elastic force of the compression spring is changed by changing the thread screwing length of the spinning brake, rotation of the spinning shaft sleeve along threads is restrained, and therefore the braking speed reduction effect of the tether is changed; the braking mechanism is effective in framework damping, low in space occupancy rate and reliable in release.

The invention relate to the technical field of textiles, in particular to an adjustable textile yarn cutting device. The problems that a traditional yarn cutting device cannot meet the use requirements of yarn of different specifications, the service life of a cutter is short, and working efficiency is low are solved through the adjustable textile yarn cutting device. The adjustable textile yarn cutting device structurally comprises a base, an air cylinder, a cutter holder, a cutter, a yarn pressing block, a spring, an adjusting block and a backup plate. The cutter holder is arranged on the base, the yarn pressing block and the adjusting block are installed in a rectangular groove of the cutter holder, and the yarn pressing block and the adjusting block are connected through the spring. The cutter is arranged at the upper end of the cutter holder, and multiple cutting teeth are arranged on the cutter. The air cylinder is arranged on the upper surface of the left side of the base, and the air cylinder and the cutter holder are connected through a pull rod. The backup plate is arranged on the upper surface of the right side of the base, and yarn guide holes are formed in an upper boss and a lower boss of the left side of the backup plate and the corresponding positions of the base. The adjustable textile yarn cutting device is easy to operate and convenient to use, and production efficiency is improved.

The invention discloses a wood board grinding device which comprises a grinding platform, a lower grinding mechanism and an upper grinding mechanism are arranged on the grinding platform, the lower grinding mechanism is arranged in the grinding platform, the upper grinding mechanism is arranged on the upper side of the lower grinding mechanism, and clamping conveying mechanisms are arranged on the two sides of the lower grinding mechanism and the two sides of the upper grinding mechanism correspondingly. The upper grinding mechanism and the lower grinding mechanism are each internally and rotationally connected with a grinding roller cutter structure. The wood board grinding device has the advantages that the inner driving shaft drives the outer cutter roller sleeve to rotate according to the structural design of the grinding roller cutter, when the cutter is clamped by a wood board, the outer clamping piece is separated from the clamping groove, so that the inner driving shaft and the outer cutter roller sleeve can generate relative rotation, and a motor is prevented from being burnt out under the cutter clamping condition; the insertion depth of an adjusting shaft core arranged in the inner driving shaft can be adjusted through a jackscrew, a circular-truncated-cone-shaped adjusting block arranged on the adjusting shaft core can abut against the inner clamping piece, and the elastic force, for extruding the outer clamping piece, of a first spring is effectively changed by changing the contact position of the adjusting block and the inner clamping piece.

The invention discloses an under-actuated biped robot which comprises a waist, legs and foot soles. The upper ends of the legs are connected with the waist through hip joints. The lower ends of the legs are connected with the foot soles through ankle joints. The under-actuated biped robot is characterized in that each of the ankle joints comprises three driving rods arranged on any three non-overlapped vertical planes where the central axis of the corresponding leg is located, wherein the upper ends of all the driving rods are respectively hinged to the legs, the lower end of each driving rod is hinged to a driven rod, and the lower end of each driven rod is connected with the corresponding foot sole through a spherical joint. According to the under-actuated biped robot, rotation of the joints at any angle is controlled by a plurality of drivers in a linkage mode, so that the flexibility of rotation of the joints at any angle is good, and the precision of rotation of the joints at any angle is high.

An elasticity adjustable mattress comprises a mattress frame, a cushion body, a plurality of pressure springs and a bottom plate, wherein the bottom plate is arranged on the bottom surface in the mattress frame, the cushion body is arranged on the upper surface of the mattress frame, and the pressure springs are uniformly arranged between the cushion body and the bottom plate; the elasticity adjustable mattress further comprises elasticity adjusting devices corresponding in number to the pressure springs and used for regulating the elasticity of the pressure springs; the elasticity adjusting devices are uniformly arranged on the surface of the bottom plate; the elasticity adjusting devices are in driving connection with one ends of the pressure springs, the surfaces of the other ends of the pressure springs are provided with a rubber cushion, and the rubber cushion props against the bottom surface of the cushion body by the elastic force of the springs and is fixedly connected with the cushion body. According to the elasticity adjustable mattress disclosed by the invention, the elasticity adjusting devices are provided, the elasticity adjusting devices are in driving connection with one ends of the pressure springs, and the tightness degree of the pressure springs is adjusted by the elasticity adjusting devices to change the elastic force of the pressure springs; since the elasticity adjusting devices correspond to the pressure springs, the hardness of different locations of the mattress can be adjusted, and the mattress is adaptive to various users with different hardness requirements on the mattress.

A damping-rigidness-controllable double-freedom-degree vibration active control platform comprises a cross-shaped beam frame and a square base which are connected through a flexible hinge. A cross-shaped beam of the cross-shaped beam frame is distributed in the diagonal directions of the square base. A structure column is arranged at the center of the cross-shaped beam frame. Sensors and actuators are connected between the lower portions of the diagonal top ends of the cross-shaped beam frame and the square base respectively. Four limiting columns are arranged between the cross-shaped beam of the cross-shaped beam frame and the square base respectively. Prearranged gaps are reserved between the limiting columns and the cross-shaped beam frame. Four balancing weights are fixed on the lower portion of the cross-shaped beam frame between the sensors or the actuators and the limiting columns respectively. Twisting limiting spring pieces are arranged at the symmetrical positions on the lower portion of the cross-shaped beam frame between the limiting columns and the flexible hinge. The electromagnetic type sensors and the electric-damping electric-rigidness actuators are used to achieve detecting of angular speed and actuating, the flexible hinge and the spring piece with changeable thickness are combined to achieve controllable damping and rigidness in a quantifying mode, and double-freedom-degree vibration active control in the x direction and the y direction of the structure is achieved.

The invention discloses a damping base for mechanical equipment, and relates to the technical field of mechanical equipment accessories. The damping base for the mechanical equipment comprises a box,a separating plate is fixedly installed in an inner cavity of a bottom box, a first threaded rod and a second threaded rod are arranged on the two sides of the bottom of the separating plate, the first threaded rod is located on the right side of the second threaded rod, the top ends of the first threaded rod and the second threaded rod penetrate a base plate of the separating plate and extend tothe upper portion of the separating plate, the surface, located at the lower portion of the bottom box, of the first threaded rod is sequentially and fixedly provided with a first belt wheel and a second belt wheel from top to bottom, the surface, located at the lower portion of the separating plate, of the second threaded rod is fixedly provided with a third belt wheel, and a rotating motor is fixedly installed on the right side of the box. According to the damping base for the mechanical equipment, the first threaded rod and the second threaded rod rotate to drive a threaded plate to rise, aspring is pressed, and therefore elasticity of the spring on a lifting plate is changed; and by means of the design, an operator can conveniently adjust the damping amplitude of the device, and the damping efficiency is improved.

The invention relates to the technical field of spring three-jaw clamps, and discloses a spring three-jaw clamp for trickling paint of an engine rotor. The clamp comprises an operation box, the bottom of the operation box is movably sleeved with a rotating shaft, and the upper part of the rotating shaft is fixedly sleeved with a turntable located in an inner cavity of the operation box. By rotating a bolt, the bolt moves and rotates in the inner cylinder due to the fact that the bolt is in meshed connection with the inner cylinder, and the bolt can drive the rotating shaft to rotate when rotating due to the fact that the bolt is connected with a first moving groove in the rotating shaft through a connecting disc and a second moving block; moreover, when a bolt moves, a second moving block moves in a first moving groove under the condition that the position of a rotating shaft is not changed, a rotating disc is driven to rotate, and due to the shape characteristics of a moving through groove, a guide rod moves along an inner cavity of a square opening along the track of the moving through groove, so the distance between the first moving block and the center of the operation box is changed; and the range of the size of parts clamped by the spring three-jaw clamp is widened.

The invention discloses a damping protection device for the mechanical equipment. The damping protection device for the mechanical equipment comprises a supporting plate, wherein a plurality of groups of guide sliding rods are symmetrically and glidingly inserted and arranged onto the supporting plate; and a protection plate and a synchronous plate are jointly and fixedly installed at the upper ends and the lower ends of the plurality of groups of guide sliding rods; an air cylinder sliding block is slidably installed on the section, located above the supporting plate, of each group of the guide sliding rods; detection cylinders are symmetrically and fixedly installed on the supporting plate; and the upper end of each detection cylinder slidably penetrates through an air cylinder sliding block and is slidably provided with a supporting rod in an inserted mode; and the upper end of each supporting rod extends to the position above the protection plate and is provided with an assembling plate. The vibration amplitude change is detected, the force opposite to the vibration direction is provided, and the elastic force of a damping spring is changed, so that the vibration amplitude of the mechanical equipment is reduced, i.e., the active damping function is achieved; and the adjustable active protection function is achieved through contact detection on the vibration amplitude, and the influence of strenuous vibration on the mechanical equipment is reduced.

The invention discloses a spring plate with adjustable comfort, which comprises a spring plate body, a first fastener, a lifting lug, a truck floor, a telescopic rod, a first hook, a second hook, a central bolt, a first groove and The second groove, the outside of the spring plate body is provided with a first fastener, the two ends of the spring plate body are provided with lifting lugs, the lifting lugs are connected to the lower surface of the truck floor through the connecting piece, and the inside of the spring plate body is provided with a second groove. A groove and a second groove, rubber layers are installed inside the first groove and the second groove, a central bolt is arranged in the middle of the spring plate body, a second hook is arranged on one side of the center bolt, and a second hook is arranged on one side of the second hook. There is a first hook on the top, and the first hook is connected to the truck floor through a telescopic rod. This kind of spring plate can make the spring plate stretch, so that the spring plate changes its elastic force, and the first groove and the second groove inside the spring plate An inner layer of rubber dampens vibrations for increased comfort.

The invention relates to a natural gas liquefaction exchange pressure regulator which comprises a nut pressing cap (1), a connecting rod (2) and a pressing plate (3), wherein a circular through hole (4) is vertically formed in the middle of the upper end surface of the nut pressing cap (1); and a first threaded hole (11) is vertically formed in the middle of the lower end surface of the nut pressing cap (1), communicates with the circular through hole (4), and connected with a threaded part I (10) at one end of the connecting rod (2) or a threaded part II (10) at one end of the pressing plate (3). A pressure regulating rod of the natural gas liquefaction exchange pressure regulator provided by the invention is composed of the connecting rod and the pressing plate; when pressure regulating springs of the same specification are subjected to elasticity deviation, the elasticity of the pressure regulating springs can be controlled by adjusting the length of the pressure regulating rod; and accordingly, the pressure regulating springs of the same specification can be used under the circumstance of different air outlet pressure and different flow.

The invention relates to a low-end adjusting mechanism for vehicle suspensions and is used especially for compensating rolling and pitching motions and for leveling purposes. In said low-end adjusting mechanism for vehicle suspensions, a vehicle spring (1) that has a longitudinal axis is mounted between two spring seats (2, 3), and at least one spring seat can be adjusted in the direction of the longitudinal axis of the spring by means of rod-shaped coupling elements (7) which are hingedly mounted at both ends.

The invention discloses an automobile rubber spring seat comprising an installation base. The inner side of the installation base is connected with installation threaded rods through bearings in a rotating manner. The outer sides of the installation threaded rods are connected with a movement buckle plate through thread engagement. The movement buckle plate is located on the inner side of the installation base. The installation threaded rods penetrate the side wall of the installation base and extend to the outer side of the installation base. Spring fixing hooks are arranged on one side of the movement buckle plate, penetrate one side of the installation base and extend to the outer side of the installation base. A spring is arranged at the tail ends of the spring fixing hooks. An inner sleeve rod is arranged inside the spring. One end of the inner sleeve rod is fixedly connected with one side of the installation base. The automobile rubber spring seat is provided with the threaded rods, a sliding pressing plate and the inner sleeve rod, and the problem that because when the automobile rubber spring seat is used, it is hard to change the initial elastic force of the spring throughthe automobile rubber spring seat, the use effect of the automobile rubber spring seat is influenced is solved.

The invention relates to a metering valve (1), which metering valve includes at least a valve housing (6), a channel (7) and a valve body (2) which is movable in order to open and close the metering valve (1), The metering valve also has a spring (3) which exerts a spring force on the valve body (2) and thereby holds the valve body (2) in the rest position, wherein the spring (3) is supported on at least one calibration body (4 ), the valve body (2), the spring (3) and the at least one calibration body (4) are arranged in the channel (7), the at least one calibration body (4) is supported by the supporting member (13), the The support part is fixed in the valve housing (6) via a material-bonded connection (5), wherein a section (14) of the support part (13) protrudes from the valve housing (6).

The constant vacuum degree mixer is used for oil burning engine, gas burning engine and oil and / or gas burning engine. Using the constant vacuum degree mixer in engine can make automobile and motorcycle saving energy by over 15 %, possessing excellent starting performance, stable idle performance, accurate gas distribution and greatly lowered exhaust pollution. The present invention has simple structure, low cost and high producibility.

In one embodiment a diagnostic test unit for analysing body fluid is provided which utilises a leaf spring (6) in combination with a seal (8), located in at least one section of a supply chamber opening, to shield the test tape (3) or test strips stored in the supply chamber (2) from the environment outside the chamber (2). The leaf spring (6) is applied directly over the opening of the storage chamber (2), closing it to the outside environment, after the chamber has been loaded with test tape or test strips and drying agent. The closing leaf spring (6) is sealed onto a face on the chamber which borders the opening and at least one section of the face is formed by a seal. The test tape or strips (3) exit through a gap between the closing leaf spring and the seal.

The invention relates to an adjusting device for an electric impact drill. The adjusting device comprises a gear case front shell, a torsion cover rotationally arranged on the top of the gear case front shell in a sleeving manner, a speed reduction mechanism arranged at the bottom of the gear case front shell, and a gear skipping structure arranged in the torsion cover. The gear skipping structure comprises an adjusting screw, a gear skipping gasket, an adjusting ring and an impact conversion gasket. The adjusting ring has the locking function on the gear skipping gasket and the impact conversion gasket. The torsion cover is provided with an upper boss, the adjusting ring is provided with a lower boss, the upper boss corresponds to the lower boss, and therefore when the torsion cover rotates anticlockwise, the adjusting ring is driven to rotate, and when the torsion cover rotates clockwise, the adjusting ring does not rotate; and in the adjusting ring rotating process, the locking function on the gear skipping gasket and the impact conversion gasket can be switched, switching of electric drill gears can be achieved, and therefore the gear switching can be achieved only through anticlockwise rotation of the torsion cover, and the effects of the short adjusting stroke and fast switching are achieved.