Provided is a ball screw device (31), including: a ball screw shaft (33); and a ball screw nut (32) which is rotatably fitted to an outer periphery of the ball screw shaft (33) through intermediation of a plurality of balls (34), wherein the ball screw shaft (33) performs a linear motion in an axial direction along with rotation of the ball screw nut (32), wherein the ball screw shaft (33) has a hollow shape having a hole portion (33b) extending in the axial direction, and wherein a stroke detection sensor (55) configured to detect an amount of displacement of the ball screw shaft (33) in the axial direction is arranged in the hole portion (33b).

A mowing sickle drive system comprises a knife bar supported by a frame and drive apparatus operable to drive the knife bar in a reciprocating linear motion at a variable drive frequency. A spring is coupled to the knife bar for applying a restoring force to the knife bar toward a neutral position when in motion. The spring has a variable modulus of elasticity that is controlled dependent upon the drive frequency.

An apparatus for actuating an end-member is disclosed. The apparatus includes a housing, a spring within the housing, and a spring plate forming a restriction for the spring within the housing. A brake member is associated with the spring plate for retaining the spring plate in one or more positions. A drive rod is associated with a motor to enable a first movement of the drive rod and to enable a second movement of spring plate. The first movement or the second movement enables the actuating of the end-member in one or more different positions for the end-member. The brake member may be engaged or disengaged to control or decouple spring compression forces in the actuator when the spring is compressed.

An electromechanical brake booster for a motor vehicle, at least one support element being fastened on a gear unit housing bottom of the gear unit, which extends along its respective longitudinal axis, a bearing device being situated on the spindle, which supports the spindle on the least one support element in such away that the bearing device is able to guide the spindle, which is set into translatory motion, at a distance from the first support element along the at least one support element. A brake system is also described.

The present invention is to provide a vehicle-mounted apparatus having a biasing structure using a coil spring capable of reducing a lateral force of a coil spring that is applied to a biasing target member. When N1, n1, N0, and n0 represent the number of effective turns when the relief valve spring 37 is set in a valve hole 34 of a spool 29 in a compressed state, a value of an integer of N1, the number of effective turns when a length of the relief valve spring 37 is a natural length, and a value of an integer of N0, respectively, the spring 37 satisfies an equation 1: 0N1n10.25 or an equation 2: 0.75N1n1<1.

An opening/closing body driving device for driving an opening/closing body is provided. The opening/closing body driving device includes: a motor, having a rotation shaft; a screw shaft, being rotated by the rotation shaft; a moving nut, being screwed to the screw shaft and moved in an axial direction of the screw shaft; and a connection part, being provided at the moving nut, wherein an arm for opening and closing the opening/closing body is connected to the connection part. The rotation shaft and the screw shaft are respectively provided on the same axis, and the connection part is provided at a radially outer side of the screw shaft.

A brake actuator (1) for a vehicle includes a housing (5) and a piston (7) movably mounted inside the housing (5) and configured to reciprocate along a stroke axis (S) between a retracted position and an extended position for applying and releasing a braking force to and from a brake mechanism (101) of the vehicle. An electric motor (3) is operatively coupled to the piston (7) and configured to move the piston (7) rod between the retracted and extended positions such as to apply and release the braking force.

A mowing sickle drive system comprises a knife bar supported by a frame and drive apparatus operable to drive the knife bar in a reciprocating linear motion at a variable drive frequency. A spring is coupled to the knife bar for applying a restoring force to the knife bar toward a neutral position when in motion. The spring has a variable modulus of elasticity that is controlled dependent upon the drive frequency.

The present disclosure relates to the technical field of aerial work platforms, in particular to a linear actuator with a contact type safety nut, and an aerial work platform. The linear actuator includes a central screw, a driving nut mechanism, and a safety nut mechanism. The central screw has a screw raceway. The safety nut mechanism includes a safety nut seat sleeved at the periphery of the central screw. Limit hole channels pointing to the central screw are arranged on the safety nut seat. An elastic buffer element is arranged in each of the limit hole channels. A safety ball is arranged between the elastic buffer element and the central screw. The contact type safety nut enables the linear actuator to always keep safety, stability, and no loss of accuracy in a conversion process that the safety nut mechanism gets involved to take effect while the driving nut mechanism fails.

An actuator (100) which comprises a motor (1), a housing (2) which wraps a periphery of the motor (1), a drive mechanism (3) of which one end is provided with a push rod assembly (34); under the function of the motor (1), the push rod assembly (34) moves forward; wherein, a returning spring (4) is arranged along external sides of the housing (2) and the drive mechanism (3), and the two ends of the returning spring (4) are respectively connected at the housing (2) and the push rod assembly (34); under the force of the returning spring (4), the push rod assembly (34) moves backward to an initial position of the push rod assembly. The actuator is simple in structure and has self-returning function.