Powered limb prostheses with multi-stage transmissions are provided.

Powered limb prostheses with multi-stage transmissions are provided.

A refrigerator includes a cabinet having a storage space; a door including a door unit to open or close the storage space and a drawer unit to provide a receiving space; rails to connect the door and the cabinet to through which the door is drawn in or out of the cabinet; a driving device disposed at the door unit to provide power; and an elevation device disposed at the drawer unit and connected with the driving device to move up or down at the drawer unit. The driving device includes: a motor assembly; a screw unit including a screw to be rotated by the motor assembly and a screw holder to move up or down along the screw; and a lever to connect the screw holder and the elevation device and rotate when the screw holder moves up or down. The motor assembly includes: a driving motor; and a power transmission unit to transmit power from the motor to the screw unit, and the screw is disposed to be inclined with respect to a vertical line passing in a top-bottom direction of the refrigerator.

Power transmission systems are provided that include polycrystalline diamond power transmission surfaces that are engaged with diamond solvent-catalyst power transmission surfaces. The power transmission systems may be or include gears, universal joints, or other power transmission systems or components.

A refrigerator includes a cabinet having a storage space; a door including a door unit to open or close the storage space and a drawer unit to provide a receiving space; rails to connect the door and the cabinet to through which the door is drawn in or out of the cabinet; a driving device disposed at the door unit to provide power; and an elevation device disposed at the drawer unit and connected with the driving device to move up or down at the drawer unit. The driving device includes: a motor assembly; a screw unit including a screw to be rotated by the motor assembly and a screw holder to move up or down along the screw; and a lever to connect the screw holder and the elevation device and rotate when the screw holder moves up or down. The motor assembly includes: a driving motor; and a power transmission unit to transmit power from the motor to the screw unit, and the screw is disposed to be inclined with respect to a vertical line passing in a top-bottom direction of the refrigerator.

A gear reduction mechanism (1) includes a drive gear (10) having a rotation axis (L.sub.1), and a driven gear (20) driven in mesh with the drive gear (10) and having a rotation axis (L.sub.2) that is noncoplanar with the rotation axis (L.sub.1). The drive gear (10) is provided with spiral teeth, each having a tooth trace of a spiral curve having a spiral center on the rotation axis (L.sub.1) and a constant radial pitch, when viewed in the direction of the rotation axis (L.sub.1). Furthermore, the tooth profile of the driven gear (20) is set, considering a tangent angle that changes momentarily as the drive gear (10) rotates.

Power transmission systems are provided that include polycrystalline diamond power transmission surfaces that are engaged with diamond solvent-catalyst power transmission surfaces. The power transmission systems may be or include gears, universal joints, or other power transmission systems or components.

Powered limb prostheses with multi-stage transmissions are provided.

Disclosed is a gearbox enabling to inhibit defective engagement between a first helical gear and a second helical gear even when a restraint torque is applied. The gearbox includes: the first helical gear; the second helical gear to engage with the first helical gear; a casing including a first member disposed in proximity to the first helical gear and a second member disposed in proximity to the second helical gear; a screw for fastening the first member with the second member, and disposed closer to the first helical gear than an engagement position between the first helical gear and the second helical gear and penetrating at least the second member; and a clip disposed closer to the second helical gear than the engagement position, and formed of a closed curve in such a manner that the first member end and the second member end are enclosed therein.

Disclosed is a gearbox enabling to inhibit defective engagement between a first helical gear and a second helical gear even when a restraint torque is applied. The gearbox includes: the first helical gear; the second helical gear to engage with the first helical gear; a casing including a first member disposed in proximity to the first helical gear and a second member disposed in proximity to the second helical gear; a screw for fastening the first member with the second member, and disposed closer to the first helical gear than an engagement position between the first helical gear and the second helical gear and penetrating at least the second member; and a clip disposed closer to the second helical gear than the engagement position, and formed of a closed curve in such a manner that the first member end and the second member end are enclosed therein.