953 results about "Brake shoe" patented technology

A wheel chock (10) is provided for a railcar. The wheel chock (10) comprises a sole (11) and a support (12) arranged on the sole (11). According to the invention, a shock-absorbing unit (14) is arranged on the support (12) to mitigate the impact of a running wheel of the railcar.

A swivel castor, having a housing which can be pivoted into a rolling direction via pivot means and two wheels rotatably mounted on the housing on a horizontal wheel axle, wherein the pivot means are arranged in front of the wheel axle, contrary to the rolling direction, and having a braking device designed to be adjustable between a braking position, in which the braking device exerts a braking force on at least one wheel, and a free-rolling position, in which the braking device releases the wheels. A brake pedal generating the braking force is pivotably mounted on the housing via a pedal axle, which extends parallel to the wheel axle and arranged between the wheels, and, in the braking position, at least one brake shoe arranged on the brake pedal exerts a braking force parallel to the wheel axle directly on one side of at least one wheel.

The invention provides a monitoring method and device for a mine hoist and a monitoring system for the mine hoist. The monitoring method comprises the steps that operation condition data of the mine hoist are obtained; according to the operation condition data, multi-angle analysis is carried out, corresponding analysis results are obtained, and the analysis results at least comprise one of the following results: the mine hoist is in a normal state, motor temperature rise of the mine hoist is abnormal, a brake shoe of the mine hoist is excessively worn, and the mine hoist has an aging risk; and executing corresponding countermeasures on the mine hoist according to the analysis results. The problem of low monitoring and early warning efficiency of the mine hoist due to lack of comprehensive monitoring of motor analysis, brake shoe clearance analysis, key point monitoring of an electric control system and environment monitoring in the mine hoist in the prior art is solved.

A bogie assembly includes a bolster having a plate on which a rail vehicle is supported, and side frames disposed on opposite sides of the plate of the bolster. The side frames can have pedestal jaw ends that can couple with wheelsets of the rail vehicle. The side frames can have openings sized to receive the bolster and springs between spring seats of the side frames in the openings and the bolster. The side frames also can include unit guide pockets that can receive brake beams that move during engagement or release of brake shoes from wheels in the wheelsets. The unit guide pockets can be located below the spring seats in the side frames.

The invention relates to the technical field of brake shoe casting, in particular to a lightweight brake shoe and sand mold casting mold, the mold comprises a male mold and a female mold which are used for forming a sand mold, the surface of the male mold is provided with a first convex block, a first pouring cup and a pouring gate system, and the first convex block is provided with a first casting mold; the pouring gate system comprises a transverse pouring gate, an inner pouring gate and an inner pouring gate, the transverse pouring gate is connected with the first pouring cup, and the inner pouring gate is located at the upper end of the first boss and correspondingly arranged between two rib plates of the brake shoe; the female die comprises a second die plate, a first groove and a second pouring cup are arranged on the surface of the second die plate, and a plurality of second casting molds are arranged in the first groove. The inner pouring gate is arranged at the upper end of the shoe plate of the brake shoe and between the two rib plates, so that during pouring, mold filling of the large-face shoe plate and mold filling of the small-face shoe plate can be conducted in sequence from bottom to top, the problem of cold shut shrinkage porosity is avoided, and the machining procedures of the brake shoe are reduced.

The utility model relates to the field of railway product part processing and manufacturing, in particular to a shoe holder for a composition brake shoe friction and wear experiment, which comprises a bottom plate, fixing screw holes are arranged on the bottom plate, two support plates which are oppositely arranged are fixedly mounted at the top of the bottom plate, and arc-shaped surfaces matched with steel backs of composition brake shoes are arranged at the tops of the support plates. A tile nose is arranged in the middle of the back face of the steel backing, and a positioning groove matched with the tile nose is formed in the top of the supporting plate. A plurality of connecting columns are fixedly installed between the two supporting plates, the connecting columns are arranged in two rows up and down, each row of connecting columns are distributed in an arc shape, tile nose fibers are arranged between the two rows of connecting columns in a penetrating mode, and the tile nose fibers penetrate through tile noses, so that the phenomena of abnormal vibration and noise in the friction and wear experiment process can be reduced; and the convenience of the friction and wear performance and physical and mechanical performance experiments of the composition brake shoe is improved.

The utility model relates to the technical field of brake shoe roller press fitting, in particular to brake shoe roller bushing press fitting equipment. According to the technical scheme, the brake shoe roller bushing press-fitting equipment comprises a back plate, a base, a bottom plate and a pressing plate, the base is installed on the bottom plate, a baffle is installed above the base, a limiting sleeve is installed above the baffle, a push plate is installed in the base, the push plate is elastically installed in the base through a spring, and the pressing plate is installed on the base. A limiting seat and a limiting shaft are arranged on the push plate, a back plate is installed at one end of the bottom plate, an air cylinder is installed on the back plate, and a push rod of the air cylinder is connected with a pressing plate through a connecting rod. According to the utility model, the roller and the bushing can be conveniently limited during press fitting, so that the assembly precision of the roller and the bushing is ensured.

A brake system may include: a drum; a brake shoe including a frictional member applying frictional force to the drum; a motor moving the brake shoe; a force sensor detecting clamping force of the frictional member to the drum; and a controller electrically connected to the motor and the force sensor, and the controller may determine a first position of the frictional member to the drum at a braking force generation start time based on current applied to the motor or torque of the motor upon controlling the motor for braking, and control the motor so that an interval between the drum and the frictional member is adjusted based on the first position when the force sensor is in a failure state upon controlling the motor for releasing the braking.

The utility model discloses an elevator brake and a braking force processing system, and relates to the technical field of elevator brake action state and braking force monitoring, the elevator brake is installed on a machine base of an elevator traction machine and makes contact with a brake wheel, the elevator brake comprises a static iron core, a movable iron core, a brake shoe and a pressure sensor, the static iron core is connected with the machine base, the movable iron core is installed on the static iron core, the brake shoe is arranged on the movable iron core and is close to the brake wheel, and a friction plate is installed between the brake shoe and the brake wheel. The pressure sensor is installed between the movable iron core and the brake shoe, the pressure sensor is used for detecting the pressure value between the brake shoe and the movable iron core, when the state of the brake shoe is changed, the pressure sensor can detect the pressure value in time, the situation that a detection blind area exists when a microswitch is adopted is avoided, and the using safety of an elevator is improved.

The invention discloses an intelligent anti-slip brake shoe and a cloth manufacturing method thereof, and relates to the technical field of anti-slip brake shoe equipment, the intelligent anti-slip brake shoe comprises an anti-slip brake shoe sole, an anti-slip control unit, two anti-slip brake shoe vertical plates and an anti-slip brake shoe pedal, one side of the anti-slip brake shoe sole in the length direction is set as a head end, and the other side of the anti-slip brake shoe sole is set as a tail end; the two anti-slip iron shoe vertical plates are symmetrically arranged on the upper end face of the anti-slip iron shoe sole in parallel in the length direction of the anti-slip iron shoe sole, the anti-slip iron shoe pedal is erected on the two anti-slip iron shoe vertical plates, and the anti-slip iron shoe sole, the anti-slip iron shoe vertical plates and the anti-slip iron shoe pedal are spliced to form a containing cavity. A front opening is formed in the side, close to the head end, of the containing cavity, the anti-slip control unit is arranged in the containing cavity, one end of the anti-slip control unit extends out of the front opening, and intelligent deployment and control anti-slip of the wheels can be achieved.

The utility model relates to the field of electronic brake actuating mechanisms, and discloses a running and parking brake actuating mechanism of a drum type electronic mechanical brake, which comprises a brake driving motor assembly, a brake cylinder, brake shoes and a brake drum, the connecting ends of the two brake shoes are movably installed on the two sides of the brake cylinder. The brake cylinder comprises a cylinder shell and a steel ball sleeve assembly, the steel ball sleeve assembly comprises a rotating wheel and push discs on the left side and the right side of the rotating wheel, the rotating wheel is in transmission connection with the brake driving motor assembly, and annular grooves are formed in the rotating wheel or / and the push discs on the left side and the right side opposite to the rotating wheel. Balls used for pushing the push disc are contained in the annular grooves in the left side and the right side correspondingly, and slope faces are arranged in the circumferential direction of the annular grooves. The rotary steel balls arranged on the two sides are opened in a sleeve mode and push the brake shoes to generate braking force, the axial size is small, occupied space is small, and response is rapid.

The utility model discloses a vehicle brake assembly and a vehicle with the vehicle brake assembly. The vehicle brake assembly comprises a brake drum in transmission connection with a wheel; the brake shoe is in transmission connection with the brake pedal and is used for pressing the inner surface of the brake drum under the driving of the brake pedal so as to prevent the brake drum from rotating and further prevent wheels from rotating; the gap measuring device is arranged on the brake shoe and is used for measuring the width of a gap between the brake shoe and the brake drum and generating a feedback signal corresponding to the width of the gap; and the braking monitoring unit is connected with the gap measuring device and used for determining the braking state of the vehicle braking assembly through the feedback signal, and the accuracy and timeliness of monitoring the braking state of the vehicle are improved.

The invention discloses an electrically-driven mechanical tread brake unit which comprises an electric brake cylinder, a hoisting arm, a brake-shoe hoist, a brake-shoe holder and a brake-shoe, the electric brake cylinder is provided with a motor located in a shell, and further provided with a planetary gear assembly connected with an output shaft of the motor and a planetary roller screw rod driven by the planetary gear assembly; the planetary gear assembly comprises a sun gear coaxially connected with an output shaft of the motor, an inner gear ring fixed to the shell, a planet gear meshed between the sun gear and the inner gear ring in a tooth meshing mode and a planet carrier connected with the planet gear, the planet roller lead screw comprises a lead screw shaft, a roller and a nut, and the planet carrier is provided with an outer gear ring. A transmission gear is fixed to a nut of the planetary roller lead screw, and an outer gear ring on the planet carrier is meshed with the transmission gear. The planetary gear and the planetary roller lead screw are arranged to replace a traditional force amplification mechanism, low-power output and large torque are achieved, and meanwhile the functions of manually resetting the lead screw and preventing the lead screw from being stuck in the fault state can be achieved.

The invention discloses a method for judging the virtual-real consistency of a brake shoe of a brake. The method comprises the following steps: arranging a sensor near the brake shoe; acquiring brake shoe stress data by using a sensor; establishing a geometric model of the brake shoe, discretizing the geometric structure of the brake shoe through finite element analysis, and establishing boundary constraints; adding a load condition to the established geometric model of the brake shoe, and solving stress distribution of the brake shoe under different working conditions through finite elements; performing inversion on the constructed brake shoe model by using the collected brake shoe stress data; and judging the virtual-real consistency of the brake shoe according to an inversion result, and obtaining a final virtual-real consistency result according to a comprehensive consistency evaluation result and a preset threshold value. According to the invention, the overall data is inverted based on the local data of the stress field, and the verification of the real-time and dynamic consistency is realized by combining the multi-dimensional consistency evaluation method, so that the precision and reliability of the health assessment of the part are effectively improved, and an innovative solution is provided for the fault early warning and intelligent maintenance of the equipment.

The present disclosure discloses a method for collaboratively controlling a multi-channel braking system of a mine hoist, including obtaining the abrasion loss of the brake shoe by detecting position information of the brake shoe of each of disc brakes in real time, dividing abrasion loss levels by determining different abrasion degrees of the brake shoe, formulating three braking force distributing modes: an average distribution, a proportional distribution, and an index distribution according to the abrasion loss levels, thereby dynamically adjusting a set braking pressure of each of the disc brakes, tracking and controlling the set braking pressure through the disc brakes by adopting a pressure closed-loop control method by utilizing a pressure signal feedback from an oil pressure sensor, implementing a collaborative braking control of the multi-channel braking system of the mine hoist based on the abrasion loss of the brake shoe.

The utility model belongs to the technical field of parking of rail locomotives, and particularly relates to an automatic parking device of a rail locomotive, which comprises a brake seat arranged on the outer side of a wheel, a mounting bin is arranged on one side, close to the wheel, of the brake seat, a telescopic brake shoe is arranged in the mounting bin, and a driving block is movably mounted on one side of the brake seat. One end of the driving block can be inserted between the brake base and the brake shoe, the driving block is used for driving the brake shoe to stretch out of the brake base or retract into the brake base, the driving block is of a rectangular columnar structure, an inclined face is arranged at the bottom of the end, close to the brake shoe, of the driving block, one end of the inclined face extends to the position between the brake base and the brake shoe, and the other end of the inclined face extends to the position between the brake base and the brake shoe. According to the utility model, the movable driving block is additionally arranged, and the distance between the brake shoe and the brake seat can be increased through the movable driving block, so that the brake shoe can be limited on the brake seat through the driving block, the brake shoe is prevented from retracting into the brake seat, and the parking stability of the brake shoe is improved.

The invention discloses a vehicle brake shoe assembly outer arc grinding machine which comprises a base, a clamping rotating mechanism, a coarse grinding mechanism, a fine grinding mechanism and a position changing mechanism are arranged on the base, the position changing mechanism enables a brake shoe assembly to be rotated to be coaxial with a rotating disc and pushes the brake shoe assembly to the rotating disc, and a positioning column on the clamping rotating mechanism is matched with a clamping mechanism to fix the brake shoe assembly. Compared with independent outer arc grinding of the brake pad, the produced combination of the brake shoe and the brake pad is better in matching degree with a brake drum, the number of adjusting times among all components during assembly is reduced, and therefore the assembly difficulty is reduced; and meanwhile, full-automatic feeding, positioning alignment, grinding and discharging are adopted, the human resource requirement is reduced, and the production efficiency is improved.

The invention discloses a powder metallurgy brake shoe for a locomotive and a preparation method, and relates to the technical field of metallurgy brake shoes, the powder metallurgy brake shoe comprises the following raw materials by mass percentage: 50%-70% of a matrix component, 10%-18% of a reinforcing component, 10%-16% of a lubricating component and 10%-16% of a friction component; the matrix component comprises electrolytic copper powder; the reinforcing components comprise reduced iron powder, superfine iron powder, atomized nickel powder, molybdenum powder and zinc powder; the lubricating component comprises artificial graphite and sulfide. According to the invention, the performance reduction of the brake shoe and the decline of a matrix at high temperature are effectively inhibited, the stability of a friction coefficient is kept, the abrasion is reduced, and the service life is prolonged.

To provide a brake shoe mounting structure of a unit brake device capable of detaching a brake shoe from a shoe head in a state where a pipe is connected to a dust collection unit.SOLUTION: A brake shoe mounting structure of a unit brake device comprises: a shoe head 37 provided with a recess part 37A into which a mounting plate 44 of the brake shoe 2 is fitted; a shoe cotter 46 that is inserted into the recess part 37A and an opening part formed in the mounting plate 44, to mount the brake shoe 2 to the shoe head 37; and a first dust collection unit 50A and a second dust collection unit 50B that collect wear powder generated when the brake shoe 2 is pressed against a tread. The first dust collection unit 50A and the second dust collection unit 50B are provided outside an insertion path of the shoe cotter 46.SELECTED DRAWING: Figure 2

The utility model provides a quick release type brake shoe assembly, which relates to the technical field of brake shoe assemblies and comprises a lining plate and a panel, a brake pad is fixedly mounted on the surface of the panel, a mounting block is fixedly mounted on the inner side of the lining plate, a sleeve plate is fixedly mounted at the top end of the mounting block, a connecting block is fixedly mounted on the back of the panel, and the connecting block is fixedly mounted on the inner side of the panel. A sliding block is slidably connected to the inner side of the connecting block, and a magnet A is fixedly mounted on the inner side of the sliding block. According to the brake pad, the mounting block, the sleeve plate, the connecting block, the sliding block, the magnet A, the bolt, the inserting block, the spring, the clamping groove and the magnet B are arranged, so that the lining plate and the panel can be quickly disassembled and assembled, the brake pad can be conveniently maintained, the maintenance efficiency can be improved, the disassembly and assembly process is simple and quick, time and labor are saved, and the practicability is high.

The utility model discloses a railway vehicle and a brake device and a brake shoe pressure detection device thereof, and the brake shoe pressure detection device comprises a brake shoe body and at least two force measurement sensors. The back of the brake shoe body is in contact fit with a brake shoe holder of a brake device; the two force measuring sensors are embedded into the back of the brake shoe body in the normal direction and symmetrically distributed on the two sides of a shoe nose of the brake shoe body, and contacts of the two force measuring sensors extend out of the back of the brake shoe body and are used for being matched with a brake shoe holder in an abutting mode. According to the scheme, the two external contact type force measuring sensors which are symmetrically distributed on the two sides of the shoe nose are embedded in the back of the brake shoe body in the normal direction, so that the brake shoe pressure detection device is simple and convenient in structure, convenient to install and good in reliability, and meanwhile, the change amount of a brake shoe friction body is small.

The invention discloses a brake device for rail transit. The brake device comprises a movable disc seat, a movable disc, a static disc, a bearing, a shell and a cylinder cover. The movable disc seat is pressed on the axle in an interference mode, the bearings are installed on the two sides of the movable disc seat, and the movable disc and the movable disc seat are installed in a matched mode and rotate circumferentially along with the axle. The static discs are arranged on the two sides of the movable disc, the static discs and the shell are installed in a matched mode, meanwhile, the shell is installed on one bearing, and the outer side of the shell is connected to a bogie swing arm to restrain circumferential rotation. The cylinder cover is mounted on the other bearing, and an oil cylinder brake shoe stack adjuster and an oil way are mounted on the cylinder cover; the edge of the shell and the edge of the cylinder cover are connected in the circumferential direction to package the movable disc and the static disc. When a vehicle is braked, pressure is applied to the oil cylinder through the oil way on the cylinder cover, the oil cylinder pushes the static disc to press the movable disc, and the movable disc and the static disc enable axle wheels to decelerate until the axle wheels are static through pressure friction torque. The braking device has the axial floating adaptation characteristic, meanwhile, the friction area is increased, and the braking heat bearing capacity is improved.

The invention relates to the technical field of damage identification, in particular to a structural defect identification method for brake shoe displacement and damage characteristics of a railway wagon, which comprises the following steps of: in the whole life cycle of the railway wagon, dividing a braking process into a plurality of stages, and performing hierarchical filing according to working condition types and service stages, constructing a brake shoe multi-working-condition structure response file; through longitudinal comparison along a time axis in the same working condition layer and transverse comparison among different working condition layers, screening out a brake shoe ectopic evolution mark and an initial brake shoe damage evolution mark which are sensitive to a structure state; encoding all evolution marks according to a spatial position, a working condition layer and a service stage to form a brake shoe ectopic and damage structure fingerprint sequence; and outputting an identification result including the structure defect type and the severity level, and generating a maintenance priority. According to the method, a space-time coupling mechanism of acoustic emission energy and temperature gradient is introduced to recognize early microcrack propagation, and the recognition sensitivity of recessive fatigue and complex damage modes is improved.

The invention relates to a brake shoe and brake head connecting structure, an assembling method and a railway vehicle, the brake shoe and brake head connecting structure comprises a brake shoe and a brake head, the brake head comprises a first side plate and a second side plate, a connecting plate is arranged between the inner edges, used for being matched with the brake shoe, of the first side plate and the second side plate, and a hole is formed in the middle of the connecting plate. Protrusions are arranged at the two ends of the connecting plate, a spring piece is fixed to the back face, used for being matched with a brake head, of the brake shoe, a first bent part is arranged at the end of the spring piece, the first bent part wraps the protrusion at the corresponding end so that the spring piece can be connected with the connecting plate in a clamped mode, and an outwards-protruding structure in the middle of the spring piece penetrates through an opening in the middle of the connecting plate. By the adoption of the connecting structure, the defects existing when a brake shoe bolt is adopted are overcome.

The utility model relates to a brake shoe clamp, which relates to the technical field of railway vehicle maintenance equipment and is used for solving the problems of complicated process and low carrying efficiency of a manual brake shoe carrying mode. The brake shoe clamp comprises a first clamping arm which partially extends into the first through hole to prevent the brake shoe from rotating; the second clamping arm and the first clamping arm are oppositely arranged in the first direction, and the second clamping arm partially extends into the second through hole to prevent the brake shoe from rotating; the driving mechanism is connected with the first clamping arm and the second clamping arm, and the driving mechanism is used for driving the first clamping arm and the second clamping arm to get close to each other or get away from each other in the first direction; the first clamping arm and the second clamping arm can be close to each other in the first direction so as to clamp the protrusion. The brake shoe clamp is matched with an external manipulator, so that mechanical carrying of the brake shoe can be realized. Therefore, the carrying efficiency of the brake shoe is improved.

The invention discloses an organic synthetic friction material, a brake pad / brake shoe and a preparation method of the brake pad / brake shoe, belongs to the field of train braking, and aims at solving the problem that an existing organic synthetic brake pad is poor in heat resistance in the braking process of a high-speed train provided with a carbon ceramic disc. The organic friction material is prepared from the following materials: a matrix, a matrix reinforcing component and a friction adjusting component, wherein the matrix comprises epoxy resin, a toughening agent, nitrile rubber powder and peroxide, the matrix reinforcing component comprises organic montmorillonite, zinc methacrylate and carbon nanotubes, and the friction adjusting component comprises aluminum oxide ceramic particles, copper sulfide and brucite. The organic synthetic friction material disclosed by the invention can meet the working condition that the operation speed of a train equipped with a carbon ceramic disc is 250km / h or above, and can be used for train braking of the train equipped with the carbon ceramic disc in high-speed operation. The invention further discloses a brake pad / brake shoe and a preparation method thereof.

The invention belongs to the technical field of brake shoe detection, and particularly relates to a brake shoe thickness measurement method and system based on 3D machine vision analysis, and the method comprises the steps: obtaining a reference point cloud picture and a reference envelope box of a brake shoe, and calibrating a thickness measurement direction on the brake shoe; obtaining a current point cloud picture of the brake shoe, registering the current point cloud picture with the reference point cloud picture, extracting a brake shoe region from the current point cloud picture by using the reference envelope box, and carrying out clustering denoising to obtain a to-be-detected brake shoe region point cloud; segmenting and clustering point clouds obtained by routing inspection; projecting the segmented and clustered point cloud to a two-dimensional plane, and carrying out ROI value calculation on the two-dimensional projection of the point cloud of the brake shoe region as an actual brake shoe point cloud; extracting a brake shoe plane point cloud from the actual brake shoe point cloud; and according to the calibrated thickness measurement direction, searching a point pair with the farthest distance in the brake shoe plane point cloud, and calculating the distance as the brake shoe thickness. The method is high in measurement precision, low in requirement for in-place shooting precision and capable of being deployed on a mobile robot.

The present invention discloses an intelligent detection and analysis device for brake shoe cracks of subway vehicles and its control method, which relates to the technical fields of railways, subways and electromechanical equipment. The detection and analysis device includes a camera assembly, the camera assembly communicates with a chip assembly, the chip assembly communicates with a main chip, and the operation result of the main chip is displayed through a display; it also includes an audio sensor and an alarm; the information collected by the audio sensor is input into the main chip, and the main chip can drive the alarm to give an alarm. The control method applied to the above detection and analysis device can automatically detect the number and position information of cracks on each brake shoe, judge the state of the brake shoe and draw a conclusion on whether replacement is needed, and visually display it through the display; the audio sensor is used to assist in analyzing the brake shoe cracks, and when the vehicle noise is detected to be too loud, the alarm emits an alarm sound. The present invention solves the problems existing in the traditional detection methods, such as high consumption of manpower and material resources and low detection efficiency.

The utility model provides a bogie device for track engineering machinery. The bogie device for the track engineering machinery comprises four sets of primary suspension devices which are installed at the positions, close to the two sides, of the bottom of a framework respectively. Two axles are installed at the positions, close to the two sides, of the bottom of the framework through axle box devices respectively, wheels are installed at the two ends of each axle respectively, lever type foundation braking devices are installed at the positions, close to the two sides, of the bottom of the framework respectively, each lever type foundation braking device comprises two braking levers, and the braking levers are arranged on the two sides of the framework respectively. The top end of one brake lever is provided with a horizontal lever body through a connecting rod, and the other end of each horizontal lever body is provided with a brake cylinder. According to the bogie device for the track engineering machinery, the basic braking capacity of a vehicle is effectively improved by increasing the configuration number of the brake shoes, the cost reduction effect is obvious compared with a unit brake type basic braking device, and meanwhile higher application stability is achieved.

A freewheel assembly has a hub, a brake mechanism, and at least one switch. The hub has an axle, a hub shell mounted around the axle, a drive screw disposed at one of two ends of the hub shell; and a sprocket mounted around the drive screw and having an inner shell and an outer shell. The inner shell is screwed with the drive screw and has a first engaging notch. The outer shell is mounted around the inner shell and has a second engaging notch. The brake mechanism has a clutch cone configured to be driven by the drive screw to move along the axle and at least one brake shoe disposed to an exterior circumference of the clutch cone. Each switch is screwed to the outer shell and has an engaging block engaging with at least one of the first engaging notch and the second engaging notch.