An oil pump includes: an annular stator (2) having coils (22); a cylindrical outer rotor (3) having a plurality of permanent magnets (24); an inner rotor (4) positioned eccentrically to an inner peripheral side of the outer rotor (3); six linkage plates (5) which link between the outer rotor (3) and the inner rotor (4); and a drive shaft (6) on which the inner rotor (4) is attached. A pump action is obtained by rotating the outer rotor (3) and the inner rotor (action is obtained by rotating the outer rotor (3) and the inner rotor (4). Each of linkage plates (5) has a symmetrical cross sectional shape. A torque transmission is possible in the same way even if the outer rotor (3) is at a drive side and even if the inner rotor (4) is at the drive side.

To reduce frictional heat generated between a rotation shaft and a bearing portion in a gear pump in which the rotation shaft having a gear mounted thereon is received by the bearing portion and an image recording apparatus having the gear pump. Provided is a gear pump which has a rotation shaft, a bearing portion which receives the rotation shaft, and a gear which is mounted on the rotation shaft and rotates with the rotation shaft, in such a manner that the gear feeds liquid. Furthermore, at least either a concave portion or a convex portion is provided in at least either the rotation shaft or the bearing portion.

An operable implant adapted to be implanted in the body of a patient, the operable implant comprising an operation device and a body engaging portion, wherein the operation device comprises a first unit comprising a receiving unit for receiving wireless energy and a first gear system adapted to receive mechanical work having a first force and first velocity, and output mechanical work having a different second force and a different second velocity. The operation device further comprises a second unit comprising an electrical motor adapted to transform electrical energy to the mechanical work, and a distance element adapted to separate the first and second units such that the receiving unit, when receiving wireless energy, is not substantially affected by the second unit.

An operable implant for hydraulically constricting the urethra of a patient for treating urinary incontinence, the operable implant comprising: a hydraulic constriction device for constricting the urethra, an operation device for operating the hydraulic constriction device, a connecting portion for connecting the operation device to the hydraulic constriction device, the connecting portion comprising at least one conduit for transferring hydraulic fluid from the operation device to the hydraulic constriction device, wherein the operation device comprises a reservoir for holding the hydraulic fluid to be transferred to the hydraulic constriction device, the reservoir comprising a movable wall portion for pumping fluid from the reservoir to the hydraulic constriction device.

A bushing system for use in a magnetic drive or canned motor pump, the system comprising: a bush holder having an axial recess for receiving a bush, a bush for insertion into the axial recess, the bush and bush holder each having: one or more cooperating features which abut against each other when the bush is fitted into the recess; and a recess for receiving at least part of a retention member; wherein, when the cooperating features abut, the retention member recesses on the bush holder and the bush are axially offset.