Abstract: In a fractional horsepower PMDC motor a varistor comprises an annular ring of varistor material having a heat sink bonded to one face. The heat sink includes a plurality of fan blades and is attached to a commutator of the motor. The heat sink increases the thermal capacity of the varistor to resist overheating under stall conditions and improves heat dissipation when the motor is running.

Abstract: An assembled commutator has a thermoplastics base supporting segments. A ring 15 of high temperature, non-softening material, such as phenolic, fits on a shelf on the base beneath tangs which are for hot connection, particularly forging, to an armature wire. The ring is held in place by fingers on the tangs.

Abstract: A rotor in an electric motor comprises a shaft having a commutator and armature thereon. To prevent relative movement between the armature lamination stack and the commutator, a structural coating such as epoxy resin coats the shaft between the commutator and stack. The commutator base has a coaxial recess in the adjacent end. The base is urged towards the stack while the coating is still fluid to gather up the coating so that it is of substantial thickness on the shaft, at least partially filling the recess and a radial slot in the recess wall.

Abstract: An armature for an electric motor comprises a winding having connector portions and a plurality of combined commutator segments and terminals. The terminals each have at least one slot which straddles and grips a respective connector portion to electrically connect the connector portion to a commutator segment. A base supports the commutator segments and a separate terminal support has a plurality of housings locating the terminals. By making the base separate to the terminal support, the armature may be wound with only the terminal support in position, the base being added afterwards, thus giving more room during winding. In a preferred embodiment, the support is formed of thermoplastics material, e.g. thermosoftening nylon, so that it is able to flex during insertion of the terminals and the base is of a material which will withstand higher temperatures, e.g. thermosetting plastics material or anodized aluminium.

Abstract: The connector, for example, is in the form of a terminal portion of a commutator segment and has two overlying parts. Each part is provided with a slot open at one end and the two slots are arranged so as to be only partly in register with one another so that the resulting slot in the terminal portion is narrower than each of the slots in the two overlying parts and is open at one end for receiving and gripping an armature winding portion. Non-aligned regions (as considered in a direction perpendicular to the plane of each overlying part) bordering the slots of the two overlying parts are offset, e.g. part sheared, out of the plane of the respective part towards the other part.

Abstract: A device for connecting a wire to a terminal of an electric motor comprises a planar portion having means for gripping a terminal. A slot is formed in the planar portion and straddles and grips a core of the wire, thus electrically connecting the wire to the terminal. The wire is held between a support and a clamping portion on the device.

Abstract: An armature for an electric motor comprises a winding having connector portions and a plurality of combined commutator segments and terminals. The terminals each have at least one slot which straddles and grips a respective connector portion to electrically connect the connector portion to a commutator segment. A base supports the commutator segments and a separate terminal support has a plurality of housing locating the terminals. By making the base separate to the terminal support, the armature may be wound with only the terminal support in position, the base being added afterwards, thus giving more room during winding. In a preferred embodiment, the support is formed of thermoplastics material, e.g. thermosoftening nylon, so that it is able to flex during insertion of the terminals and the base is of a material which will withstand higher temperatures, e.g. thermosetting plastics material or anodised aluminum.

Abstract: A terminal in an electric motor comprises a generally flat portion in a shallow recess in an outer wall of the motor housing for forming a touch contact with a power supply, and a U-shaped portion housed in a recess for receiving a terminal on a supply lead wire. The U-shaped portion may have a bifurcated arm for receiving a tinned wire lead.

Abstract: A resistor ring, typically a varistor, is clamped in intimate contact with terminals of a commutator using a clip-on plastic clamp having a plurality of shock-absorbing spring fingers, thus avoiding the application of heat which could damage the resistor ring.

Abstract: An electric motor and gearbox unit, wherein the gearbox comprises a casing having an integral bearing support for the motor shaft and an epicyclic gear train within the casing, the output shaft of the gearbox being precisely aligned with the motor shaft. The gearbox can be symmetrically designed with respect to the motor axis so that a fan mounted on the motor shaft can create a symmetrical flow of cooling air over the gearbox casing and into the motor. Preferably, the epicyclic gear train comprises a sun gear on the motor shaft, a ring gear integral with the gearbox casing, and a plurality of planet gears that mesh with the sun gear and the ring gear and which are each mounted for rotation with respect to a planet carrier connected to the output shaft of the gearbox. The planet carrier has to be provided with a number of holes, one being a central hole for receiving the output shaft of the gearbox and the others being for receiving stub axles for mounting the planet gears.

Abstract: A pattern recognition system has both coarse and fine levels of analysis in which a coarse array representation of a workpiece pattern is formed and used to identify the workpiece pattern as either a referench character or as a member of an ambiguous set of reference characters which are represented by identical coarse array representations. At least portions of a fine array representation of a workpiece pattern which has been classified as a member of a set of reference characters are compared to corresponding portions of fine array representations of reference characters in the set identified by the classification. The pattern recognition system has a learning system through which reference characters may be introduced into the recognition system and through which a representation of a workpiece pattern which was not identified may be incorporated into an existing set of reference characters of the recognition system.

Abstract: A pattern recognition system has both coarse and fine levels of analysis in which a coarse array representation of a workpiece pattern is formed and used to identify the workpiece pattern as either a reference character or as a member of an ambiguous set of reference characters which are represented by identical coarse array representations. At least portions of a fine array representation of a workpiece pattern which has been classified as a member of a set of reference characters are compared to corresponding portions of fine array representations of reference characters in the set identified by the classification. The pattern recognition system has a learning system through which reference characters may be introduced into the recognition system and through which a representation of a workpiece pattern which was not identified may be incorporated into an existing set of reference characters of the recognition system.