This power transmission device includes a motor, a worm connected to a rotating shaft of the motor, and a worm wheel engaged with the worm and disposed at an operation pedal side with respect to the worm, wherein a biasing member which biases the motor in a direction in which the worm and the worm wheel come in contact with each other when the motor is driven is disposed between the motor and a housing.

The present disclosure relates to a safe foothold apparatus for a platform, wherein a foothold plate protrudes from and is retracted into the platform by moving along a curved rotational route so that the foothold plate is re-retracted into the platform safely due to the operation structure even when a collision occurs between a train and the foothold plate in a protrusion state. Therefore, the present invention can prevent the foothold plate and the train from being damaged, thereby establishing safer boarding/alighting environment and stably maintaining the operational state of the foothold plate by using a frictional contact module even in an emergency situation. Accordingly, the present invention can improve safety through a simple structure, facilitate the manufacturing and establishment work by simplifying a structure of a manual operation module, reduce the size of a whole apparatus, and far enhance the operational stability.

A worm drive for a power steering system of a motor vehicle is disclosed. The worm drive includes a worm gear, a worm which meshes with the worm gear, and an electric motor which drives the worm. One side of the worm is connected by a coupling to the electric motor and the other side of the worm is mounted in a floating bearing. The coupling consists of a hub and an elastic spring bush. The floating bearing is oval-shaped in order to allow vertical movements of the worm, and the worm is spring-loaded on the worm gear by the coupling.

A gearbox assembly for power take off from an electric motor of an electric power assisted steering apparatus comprising a gearbox housing which houses a worm shaft and a gear wheel, is disclosed. The worm shaft incorporates one or more external helical worm teeth. A main bearing assembly supports the worm shaft at an end closest to the motor. A tail bearing assembly supports the worm shaft at an end furthest from the motor, in which at least the tail bearing assembly is free to move relative to the housing through a limited range of motion that enables the worm shaft to move radially away from the axis of the wheel gear. The gearbox assembly further comprises a flexible coupler which connects the worm shaft at the main bearing end to a power take off from the motor so as to transfer torque from the motor to the worm shaft. The flexible coupler comprises a first hub part providing a connection to the worm shaft, a second hub part providing a connection to the power take off from the motor, and a flexible membrane that connects the first hub part to the second hub part. The flexible membrane provides a primary path for the transfer of torque from the first hub part to the second hub part.

Systems, methods and apparatus for adjusting the depth of a trench opened by a row unit of an agricultural planter. The row unit includes a trench depth adjustment assembly configured to modify the furrow depth. In one embodiment, the depth adjustment assembly may include a gear box having one or more gears which engage with a gear rack. The gear box may be pivotally connected to a depth adjustment body supporting a rocker that adjusts upward travel of gauge wheel arms. In another embodiment, the depth adjustment assembly may include a depth adjustment arm having a screw receiver that cooperates with a driven screw that adjusts the position of the depth adjustment arm acting on the gauge wheels to adjust trench depth.

Systems, methods and apparatus for adjusting the depth of a trench opened by a row unit of an agricultural planter. The row unit includes a trench depth adjustment assembly configured to modify the furrow depth. In one embodiment, the depth adjustment assembly may include a gear box having one or more gears which engage with a gear rack. The gear box may be pivotally connected to a depth adjustment body supporting a rocker that adjusts upward travel of gauge wheel arms. In another embodiment, the depth adjustment assembly may include a depth adjustment arm having a screw receiver that cooperates with a driven screw that adjusts the position of the depth adjustment arm acting on the gauge wheels to adjust trench depth.

An embodiment of the invention provides an electromechanical rear derailleur for a bicycle including a base member that is configured to be coupled to a frame member of a bicycle. The derailleur includes a movable member and a link mechanism that movably couples the movable member to the base member. A motor is positioned at the movable member to move the movable member.

Motor device includes: motor part including armature shaft; speed reduction mechanism which includes worm and worm wheel and outputs the rotation of the armature shaft at reduced speed; gear case which is provided with bottom part and opening part and accommodates the worm and worm wheel in rotatable manner; gear cover which covers the opening part of the gear case; circuit board which is arranged between the speed reduction mechanism and the gear cover; and board cover which is arranged between the circuit board and the speed reduction mechanism. The board cover is provided with positioning protrusion part protruding toward the gear case, the gear case is provided with positioning recess part into which the positioning protrusion part is press-fit, and the bottom surface of the positioning recess part and the tip surface of the positioning protrusion part press-fit into the positioning recess part face each other with gap therebetween.

Motor device includes: motor part including armature shaft; speed reduction mechanism which includes worm and worm wheel and outputs the rotation of the armature shaft at reduced speed; gear case which is provided with bottom part and opening part and accommodates the worm and worm wheel in rotatable manner; gear cover which covers the opening part of the gear case; circuit board which is arranged between the speed reduction mechanism and the gear cover; and board cover which is arranged between the circuit board and the speed reduction mechanism. The board cover is provided with positioning protrusion part protruding toward the gear case, the gear case is provided with positioning recess part into which the positioning protrusion part is press-fit, and the bottom surface of the positioning recess part and the tip surface of the positioning protrusion part press-fit into the positioning recess part face each other with gap therebetween.

An assist mechanism includes: an electric motor in which a rotor has a magnet and a stator has a winding; a shaft-shaped member in which a worm engaged with a worm wheel is formed; and a coupling that couples an output shaft of the electric motor and the shaft-shaped member to each other. The smallest rotation order among rotation orders of the electric motor and a rotation order of the worm are prime to each other.