1208results about How to "Improve mechanical efficiency" patented technology

The invention relates to a pipeline cleaning robot applied to industrial field, and also relates to a method for controlling the walking robot. The robot comprises a connection shaft (2), a supporting leg (3), a drive plate (4), a pusher dog (5), a connection rope (8), a variable pitch motor (9), a drive motor (10), a cleaning device (12) and a roller wheel device (14), wherein the connection rope (8) passes through the drive plate (4), and is connected with variable pitch motor (9); the supporting leg (3) which can retractably rotate is connected with the drive plate (4); the drive motor (10) is connected with another frame shell end part (18) through a gear disc (17) and the connection shaft (2); the supporting leg extends out of a frame shell (13), and is contacted with the inner surface of the pipeline; and the cleaning device (12) is arranged on the frame shell (13). With the scheme, the robot is more efficient, can turn a curve smoothly, can be controlled more easily, has the advantages of simple structure and convenient manufacture, and is applicable to pipelines with different diameters.

Accommodating intraocular lens (AIOL) assemblies including a discrete pre-assembled monolithic AIOL assemblage and a discrete haptics system having a haptics ring and at least two elongated C-shaped haptics for self-anchoring in a human scleral wall at the ciliary sulcus. The AIOL assemblages include an AIOL capsule and an integrally formed base member. The AIOL assemblages also include an annular haptics support surround posterior to an anterior structure on implantation in a human eye of a supine human. AIOL assemblies are assembled in situ by mounting a haptics system onto a previously implanted AIOL assemblage. The haptics system bears against the annular haptics support surround. The anterior structure is freely telescopically received in the haptics ring.

The invention discloses extreme-pressure abrasion-resistant open gear oil which is prepared from the following components by weight: 20-40% of tackifier, 1-2% of rust inhibitor, 0.08-1% of antioxygen, 5-50ppm of anti-foaming agent, 0.05-0.4% of demulsifying agent, 0.002-1% of extreme-pressure abrasion-resistant agent, 0.2-2% of purification dispersant and the balance being base oil, wherein the extreme-pressure abrasion-resistant agent refers to nanometer grapheme. By adding the nanometer grapheme to serve as the extreme-pressure abrasion-resistant agent, the extreme-pressure abrasion resistance of the gear oil is improved, an abrasion-resistant effect is remarkable and the abrasion loss can be reduced by 52%; by utilizing effective adhesive, clearing agent, antirust corrosion-resistant additive and the antioxygen, the adhesion, viscosity-temperature characteristic and antioxidant rust resistance of the oil are ensured; and by adding the dispersant, the problem of blockage caused by poor dispersibility of the nanometer grapheme which serves as a solid extreme-pressure agent is solved.

The invention discloses a clamping mechanism which comprises a shell and an oil cylinder installed in the shell, wherein clamping blocks are distributed in the front part of the shell in bilateral symmetry; and the inner side surfaces of the front half parts of the clamping blocks are inner concave surfaces. The clamping mechanism is characterized in that a cylinder barrel of the oil cylinder is centered at the rear part of the shell; the front end of a piston rod of the oil cylinder is articulated with a connecting plate; the left part and the right part of the connecting plate are respectively articulated with the rear ends of the clamping blocks; the front part of at least one cover plate of the shell is symmetrically provided with guide grooves left and right; guide pins are arranged in the middle parts of the two clamping blocks and inserted into the guide grooves; fixed blocks are clamped and fixed in the middle parts of the front ends of the two cover plates, and the normal lineof the surfaces of the front parts of the inner concave surfaces of the two clamping blocks are inclined to the directions of the fixed blocks. The invention has simple structure, high strength and large clamping force and can be suitable for different pipe columns with the external diameter range of 3.5-9.75 inches without replacing the clamping mechanism, and the clamping mechanism can not interfere with the adjacent pipe column during working.

An apparatus for providing a building energy consumption diagnosis and a real-time commissioning processing, includes a database section configured to store building related information; a real-time commissioning section configured to diagnose energy efficiency and obstruction of the mechanical facilities using the building related information. Further, the apparatus includes a building energy consumption information analysis section configured to determine an energy consumption references and diagnose energy consumption of the buildings to be commissioned using the building related information, the real-time operation information and the measured information on the basis of the determined energy consumption reference.

A peristaltic pump includes a plurality of effecters, actuated in a periodic manner upon by obstructive forces of a flexible infusion tube so as flow of infusion fluid is provided along said infusion tube, the magnitude of the obstructive forces being dependent upon the displacement of said moving effecters; and a plurality of balancing magnets providing balancing forces upon one or all the moving effecters, the balancing forces at each point along the path of motion of the moving effecters being of approximately equal magnitude to that of the obstructive forces at the point; such that the parasitic output due to work performed against the obstructive forces is approximately zero and yield is maximized.

The invention discloses a mechanical soil-sampling device. The mechanical soil-sampling device comprises motors, a soil-sampling drill, a soil collection disc and a fixing box. A spiral inner groove is arranged at a lower end of the soil-sampling drill; outer edges of the spiral inner groove are provided with extended small flanges; the bottom end of the soil-sampling drill is processed into a cone-shaped drill head; an upper end of the soil-sampling drill is provided with a driven spur gear; the driven spur gear and a driving spur gear cooperate with each other thereby moving; the driving spur gear is installed on a main shaft of a first decelerator; the first decelerator is connected to an output shaft of a first motor; the main shaft of the first decelerator is fixedly connected to the upper end of the soil-sampling drill; the soil-sampling drill vertically and rotatingly move to pass through one of soil collection chambers; a baffle is installed in the fixing box and is located above the soil collection disc; and an end of the baffle extends into the spiral inner groove of the soil-sampling drill. The mechanical soil-sampling device has the advantages of convenient use, reliable running, simple structure, high efficiency and good applicability.

The invention relates to a membrane seawater desalination pressurization and energy recovery integrated method and a membrane seawater desalination pressurization and energy recovery integrated device. Piston rods of single-rod seawater cylinders are connected with single-rod oil cylinders to form two or more working combined bodies which operate alternately; the oil cylinders drive the seawater cylinders to move back and forth; one piston cavities of the seawater cylinders suck high pressure strong brine in the process of moving forward and drain the high pressure strong brine in the returning process; and the other piston cavities of the seawater cylinders suck raw seawater in the returning process, pressurize the raw seawater in the process of moving forward and continuously and stably output the pressurized high pressure raw seawater to a reverse osmosis membrane modulus.

The invention discloses an automatic speed changer. The automatic speed changer comprises a gear range gear transmission system and a gear shift mechanism execution system and is characterized in that: the gear shift mechanism execution system comprises an operating control device, a reverse action device and a transmission shifting device; the reverse action device comprises a control frame, a driving frame, a driven frame and a spring; the driving frame is elastically connected with the driven frame through the spring; the driving frame and the driven frame are in axial slide fit with the control frame respectively; the slide stroke of the driving frame is larger than that of the driven frame, and the middle point of the slide stroke of driving frame and the middle point of the slide stroke of driven frame are on the same plane; the operating control device can make the driving frame move so as to force the driven frame to reversely move; and the driven frame is moved to make the transmission shifting device force the gear range gear transmission system to shift so as to change the speed. The automatic speed changer has the advantages of high transmission efficiency, variable gear ranges and long service life, can be assembled on various motor vehicles and agricultural machinery and can save power and fuel when used.

The invention discloses a linear reciprocating motor. The linear reciprocating motor comprises a reciprocating screw rod (4) which is sleeved with a hollow shaft (2), a small round hole is formed in the side wall of the hollow shaft (2), a guide block (3) is placed in the small round hole of the hollow shaft and makes contact with a bidirectional sliding groove of the reciprocating screw rod (4), the hollow shaft (2) provided with the guide block (3) is sleeved with a rotor (1), and the rotor (1) is sleeved with a motor stator. According to the linear reciprocating motor, the guide block is arranged in the small round hole in the hollow shaft arranged outside the reciprocating screw rod in a sleeved mode, then the rotor is arranged uniformly, and after installation is finished, the hollow shaft rotates to drive the guide block to move in the reciprocating screw rod so that front and back linear reciprocating motion of the reciprocating screw rod can be achieved under the action of the guide block. Thus, the linear reciprocating motor can be applied to various occasions needing the reciprocating motion, the number of transmission links is reduced, mechanical efficiency is improved, production cost is reduced, and the linear reciprocating motor is simplified substantially.

The invention relates to a disc type iron-core-free PMDC motor. The disc type iron-core-free PMDC motor comprises a middle stator and rotors which are installed on a spindle and in disc shapes, disc surfaces are arranged parallelly and correspondingly, gap flux densities on two sides of the stator are the same, the stator comprises an iron-core-free rolled annular winding which is placed axially, and a magnetic line of force passes gaps and the winding axially; and each rotor is a disc composed of a magnetic conducting disc for accommodating magnetic steel and an aluminum case, a permanent magnet is bonded on the magnetic conducting disc in an N and S alternating mode, and polarities of magnetic steel corresponding to the rotors up and down are opposite. The disc type iron-core-free PMDC motor is characterized in that the annular winding is an axial symmetry conical ring composed of a plurality of sections of arcs, the central axis points to the axis of the stator, and the tip of the conical ring is close to the axis of the stator. The magneto-electricity conversion efficiency of the motor is improved by above 10%.

The invention relates to a control system and a control method for plasma excitation for cascade internal flow, which are performed under the control of a computer. By applying the plasma excitation with appropriate intensity at different positions of a cascade suction surface, on one hand, the system and the method can play a role in inhibiting the flow separation of the cascade suction surface,and on the other hand, the system and the method can improve the flow state of a cascade wake to play a role in reducing the flow loss.

A method for combusting fuel in an engine involving decreasing a first volume of gas to a second volume, in two stages, while increasing the pressure and temperature of that volume of gas (a compression process having a chosen compression ratio), then increasing the second volume to a third volume at constant pressure while adding heat until a predetermined temperature is obtained, increasing the third volume of gas to a fourth volume, in two stages while decreasing the pressure at the predetermined temperature (an expansion process having a chosen expansion ratio much greater than the compression ratio), decreasing the pressure to atmospheric pressure while removing heat under constant volume, and finally decreasing the volume of gas to the first volume while removing heat under constant pressure to complete an over expanded, limited-temperature cycle. Also disclosed is an engine employing said over expanded, limited-temperature cycle.

The invention provides a tracked magnetic suspension vehicle / a conveyer, which comprise a track, permanent magnets, a suspension seat and a driving wheel. The track is fixedly connected with the permanent magnet or a magnetizer, the suspension seat is fixedly connected with the permanent magnet, and the permanent magnet on the track and the permanent magnet on the suspension seat have homopolarity (or heteropolarity) and are arranged oppositely, generate magnetic suspension repulsive force (or attractive force) opposite to gravitational attraction, reduce or eliminate friction force when a vehicle runs, and reduce energy dissipation. The tracked magnetic suspension vehicle has the advantages of no energy consumption during suspension, low energy consumption during running, and energy saving. The tracked magnetic suspension vehicle achieves trackless magnetic suspension, also can run on a road, and is not limited by railway track any more. The tracked magnetic suspension vehicle also can be used as a magnetic suspension conveyer, and is energy-saving, clean and dustless.

The invention provides an innercurve multiple-action radial plunger type hydraulic motor, wherein, the plunger holes of a rotator are connected with rollers, a sliding bearing, a plunger and elastic retaining rings; the elastic retaining rings are evenly distributed with claw elbows in a circumference direction; two ends of the outer surface of the rotator are provided with a groove respectively; two end surfaces of the rotator are provided with notches which are communicated with the plunger holes and have the same number as the plunger holes; the elastic retaining rings are clamped in the two grooves on the outer surface of the rotator; the claw elbows on the elastic retaining rings are in clearance fit with the two end surfaces of the roller in each plunger hole; and the rollers are clamped in the middle of two claw elbows. Each elastic retaining ring is of an integral structure, thus the ring does not need to be assembled in each plunger hole independently; and only two elastic retaining rings are clamped in the grooves on the rotator so as to limit the rollers in all the plunger holes to axially move, thereby leading even stress on the rollers, enabling a hydraulic energy conversion part to work stably, improving the mechanical efficiency and the reliability of the hydraulic motor, and prolonging the service life of the hydraulic motor.

The invention discloses a double-crank mechanism engine, belonging to the technical field of engines. The double-crank mechanism engine comprises a gas cylinder and a piston capable of performing straight reciprocating motion in the gas cylinder, wherein two parallel crankshafts are arranged at the two sides of the gas cylinder; a connecting rod is hinged between corresponding crankshaft pins of the two crankshafts to form a double-crank mechanism; a connecting rod insertion slot and a slide block are arranged on a piston rod on the rear end of the piston, the connecting rod is inserted to the connecting rod insertion slot in a sliding manner, a guide block is fixed in the engine; a guide rail for sliding the slide block is formed on the guide block; the slide block is inserted to the guide rail; transmission gears are arranged on the end parts of the crankshafts; an output gear is engaged between the two transmission gears; and an output shaft is arranged on the output gear. The double-crank mechanism engine can be used for effectively lowering the abrasion and the impact of the piston and a cylinder sleeve, improving the reliability of the ceramic material applied to the engine and improving the practical heating efficiency.

A modified gear oil can be used for extreme worm oil, open industrial gear oil and closed industrial gear oil in traffic transportation, machinery, metallurgical, chemical industries. In the mineral lube-oil or synthetic lube-oil, modified nano-carbon with average grain size 2-6nm is added as extreme anti-scuff agent and oily agent, quality fraction is 2X10-5-1X10-2, nano-diamond occupies 10-99%, wear rate is decreased by 46.7%, mechanical efficiency improves by 2.84%, polishing scratch depth is decreased from 4.94 mu m to 0.07 mu m.

Described herein are embodiments of a boundary layer effect turbine and a hydrodynamic speed reducer. Described is a boundary layer effect turbine that utilizes the phenomena of the boundary layer to drive a turbine impeller that is made of a plurality of spaced disks oriented along a rotatable shaft. As operating fluid is directed over surfaces of the plurality of disks of the boundary layer effect turbine, energy is transferred from the fluid to the disks as a result of the adhesive and viscous properties of the fluid.

The invention relates to an omni-directional movable automatic ball picking and ball dribbling assistant training robot, which comprises five part, a directional moving chassis bracket I, a ball collecting mechanism II, a ball dribbling mechanism III, a baffle stopping mechanism IV and a ball serving mechanism V, wherein the chassis bracket comprises a base 1 and three omni-directional wheels 3 which are driven by independent motors; the ball collecting mechanism II is provided with ball collecting hairbrushes, and balls are collected into a ball collecting cage 9 through the rotation of the ball collecting hairbrushes which are driven by a ball collecting motor; the balls, which are collected in the ball collecting cage, are transferred to the ball stopping mechanism IV by virtue of the ball dribbling mechanism III; the ball stopping mechanism IV is fixedly connected to a ball cage fixing plate 34, and the ball stopping mechanism is a group of mechanism by which the ball dribbling mechanism III and the ball serving mechanism V are separated and intermittent ball serving is implemented; and when the ball serving mechanism V serves balls, two synchronous belts 39 are opposite in rotating direction, and a ball serving angle is adjusted by adjusting the travel of a push rod motor 45.

A push-pull chain (1) that can bend in one direction only, and is provided with at least two rollers (12,13) on each of the driving pins, one of the rollers (12) engages a drive sprocket (29) and the other of said at least two rollers (13) engages a chain guide surface (28). An actuator (20) for e.g. opening and closing a window that uses this dual-roller push-pull chain. A link (105) driven push-pull chain (101) that can bend in one direction only, with links (105) that is shaped as an engagement surface for engaging a drive sprocket (129). An actuator (120) for e.g. opening and closing a window that uses the link driven push-pull chain.

The invention discloses a power matching control system for a novel energy-saving double-drum vibratory roller. The power matching control system comprises a controller, a travel state control device, a frequency adjusting switch, a compaction / travel selection switch of the travel state and the compaction state of a roller and a speed sensor for detecting the rotate speed of an engine of the roller in real time, wherein a travel pump electromagnetic valve and a travel motor electromagnetic valve are controlled by the controller; a vibratory pump electromagnetic valve is connected with the controller which staggers the power peak values of a travel mechanism hydraulic drive system and a vibratory compaction hydraulic drive system by controlling the starting time of the vibratory pump electromagnetic valve; moreover, when the roller is in compaction work mode, the vibratory pump electromagnetic valve is correspondingly controlled and started by the controller according to a signal detected by the speed sensor. The power matching control system has reasonable design, simple use and operation, reliable performance and good use effect; moreover, the control system can effectively reduce the installed power of the vibratory roller, reduce power consumption and save use cost while reliably restraining the momentary power of the travel system and the vibratory system of the roller.

The invention discloses a continuous feeding device for an electric arc furnace preheated by flue gases. The device comprises a double-duct conveying trough and a flue gas guiding hood; a carrier plate with a flue gas channel is arranged in the middle part of the double-duct conveying trough; a material circulating duct is arranged above the carrier plate, and a flue gas circulating duct is arranged below the carrier plate; a seal gate matched with the upper opening of the lower end of the material circulating duct is arranged on the flue gas guiding hood; the double-duct conveying trough forms a flue gas diffusion heat exchanging mechanism from bottom to top, contact area between materials and high temperature flue gas is enlarged, the stay time of the flue gas is long, and the material preheating effect is greatly improved; as the double-duct conveying trough is arranged in an inclined way, the feeding point is raised, the trough bevel is large, the waste steel material blanking point can easily close to the center high temperature area of the furnace, so that the cold area phenomenon is eliminated; as the diffusion and heat exchange designs are realized, the powder dust in the exhausted flue gases is greatly reduced, the flue gas flowing is more in line with the natural rules, and the problems of exhaust pipe blockage and the like are solved.

A travelling wave ultrasound motor with a dual stator and rotor multi-diameter shaft structure belongs to the technical field of ultrasound motor. Two groups of stators and rotors are arranged between the external fixing structure and the internal supporting structure of the motor, wherein the external fixing structure is composed of two stator seats arranged opposite to each other, and a drum-shaped shell arranged between the stator seats, the internal supporting structure is formed by limiting the shaft position of the multi-diameter shaft by thrust bearings in the stator seats. The invention not only maintains the advantages of the existing ultrasound motor with single stator and rotor, but also is easier to operate, has more contact structure, higher torque to capacity ratio and stronger anti-interference capacity to external load, thus being especially suitable for fields of aerospace and biomedicine.

The invention discloses an integrated hydraulically-driven permanent magnet synchronous generator which comprises a motor shell (25), a rotating shaft (24), a cylinder body (23), a permanent magnet (26) and a motor stator (27), wherein the right side of the cylinder body (23) is tightly attached to an oil distribution disk (20), and the left side of the cylinder body (23) is provided with an inclined disk (31); a plunger hole (32) is arranged in the cylinder body (23), a plunger (8) positioned in the plunger hole (32) is rotatably connected with a slide shoe (6), and the slide shoe (6) is tightly attached to the inclined disk (31); an oil inlet (15a) on an oil-pass joint block (16), an oil inlet passage in a right end cover (17) and an oil inlet window on the oil distribution disk (20) are communicated in sequence; and an oil outlet (15b) on the oil-pass joint block (16), an oil outlet passage in the right end cover (17) and an oil outlet window on the oil distribution disk (20) are communicated in sequence. The permanent magnet synchronous generator is used for converting hydraulic energy into electric energy.

The modular transmission uses only a pair of small and light hydraulic machines of remarkably improved volumetric efficiency with pistons having body portions substantially as long as the axial length of the respective cylinders in which they reciprocate. The two hydraulic machines operate in a closed loop, one being used as a pump driven by the vehicle's engine, and the other used as a motor. Each machine has a fully articulatable swash plate. By computer control, the angles of the swash plates of the two machines are infinitely varied to provide an appropriate optimum ratio of engine / wheel speed for all conditions from start-up, city driving, hill climbing varied according to load and steepness, and over-drive for highway. This complete vehicle operation is attained while the vehicle's engine continues to operate at relatively constant speeds and relatively low RPM.

The invention relates to a three-dimensional vertical axis rotating driving barrel wall type grooved pulley mechanism that includes grooved component and grooved wheel. The stir groove component of the grooved wheel and the located half arc flute are distributed on the circle of the barrel wall. The diving shaft of the stir groove component, the located half arc and the rotating rocker are fixed together, shifting shaft and the rotating rocker are fixed together. Shaft sleeve is actively installed on the shifting shaft. The rotating axis lines of the stir groove component, the shifting shaft and the grooved wheel are joined at one point in the three-dimensional space. The invention is simple structure, good technical, easy to be machined and reduces the entire volume of the transformer tapping switch.

The invention relates to a lean-burn gas duel-fuel spark-ignition-type internal combustion engine based on EGR (Exhaust Gas Recirculation) system and a control method, and can solve the problems of unstable combustion, high NOx emission and the like of a gas fuel spark-ignition-type internal combustion engine caused during lean burn. Based on the in-fuel-gas-cylinder direct injection and inlet duct spray combined duel-fuel spark-ignition-type internal combustion engine technology and the EGR technology, the internal combustion engine and the control method ensure that the duel-fuel spark-ignition-type internal combustion engine can realize stable and efficient lean burn and reduce the phenomena of cyclical variation and fire accident at a high compression ratio; meanwhile, part of exhaust gas is re-guided into the cylinder to participate in combustion, the EGR ratio is changed according to the requirements of working conditions, the in-cylinder combustion temperature is lowered, and the generation of NOx is inhibited; and besides, as lean burn and EGR co-exist, the opening degree of a throttle valve can be increased and the pumping loss is reduced. In conclusion, reduction of energy consumption and super-low emission of pollutants can be fundamentally realized.

The invention discloses an actuating tower type pumping unit of a low-velocity big-torque special-shaped motor, which is characterized by comprising a tower cylinder fixed on a cement basement, a digital intelligent control cabinet, a special-shaped motor on the top platform of the tower cylinder, a load hoisting belt wound round the roller of the special-shaped motor, and a balance box connected with the load hoisting belt. One end of the load hoisting belt is fixedly provided with a hanging rope or a hanging unit, while the other end of the load hoisting belt is connected with the balance box. The load hoisting belt is driven by the special-shaped motor to transmit torque forwardly and reversely. The rotating speed, the steering and the torque of the special-shaped motor are regulated and controlled by the digital intelligent control cabinet. The forward and reverse rotation of the special-shaped motor is converted to the reciprocating linear motion of a sucker rod so as to realize the oil pumping cycle of the pumping unit. The pumping unit is simple in structure and the intelligent controller thereof can be controlled automatically, manually or remotely. Thus, the perfect combination of high intelligence and fool-style operation is realized. The pumping unit is only provided with two lubricating points and can be operated for years without being lubricated. No easily damaged part is adopted by the whole pumping unit, while the pumping unit is time-saving and labor-saving in transportation, installation, use and maintenance.

The invention discloses a bidirectional overrunning clutch, a speed control device and an automatic speed control system. The bidirectional overrunning clutch comprises a disc-shaped driving part, wherein the disc-shaped driving part can rotatably sleeve a shaft-shaped driven part; a spiral spline sleeve is in spiral spline fit with a journal of the driving part, and a braking device which is used for applying frictional resistance to the spiral spline sleeve is connected to the spiral spline sleeve; a first end surface engagement clutch structure and a second end surface engagement clutch structure are formed between the spiral spline sleeve and the driven part, and the first end surface engagement clutch structure and the second end surface engagement clutch structure are respectively used only for the spiral spline sleeve to drive the driven part to synchronously rotate clockwise and anticlockwise; a bidirectional clutch structure is formed between high and low-speed driven gears of the speed control device and the automatic speed control system. The bidirectional overrunning clutch has the beneficial effects of small cross-sectional dimension, convenience in application, high mechanical efficiency, strong loading capability and long service life; two-gear automatic transmission and reverse output can be realized by the speed control device.

The invention discloses a speed changer capable of solving the problems of large size, complex operation, high maintenance cost, and the like of the traditional speed changer. The speed changer has about 97 percent of transmission mechanical efficiency and easy and convenient operation and is characterized in that a power input gear can be fixed with a jacket; a sliding sleeve is matched with thejacket through a helical rack and is matched with a gear shaft through a spur rack; a pin shaft of the sliding sleeve contacts with a push rod of a gear shift shuttle; a crank arm is movably connected with a lug through the pin shaft; a shifting fork forks on a shaft rod of a push-and-pull rod; a hollow cavity or a sliding chute of the gear shaft is internally provided with the gear shift shuttle; the gear shift shuttle is provided with a top bulge; the gear shaft is provided with a sliding key and is assembled with an angle gear matched with a chamfered groove strip and a plurality of gearshift gears; the gearshift gears can be respectively meshed with a driven gear; the driven gear is assembled on a driven shaft; and the driven shaft is fixed with a power output gear. The invention can be used for an epicyclic gear train and realize the full-automatic speed change from two gears to more than ten gears.