Patent GB-1258121-A (GB)
IPC: H02K33/02
Filed: 1969-02-20
Abstract: 1,258,121. Reciprocating motors. M. BARTHALON. 20 Feb., 1969 [23 Feb.; 1968], No. 9247/69. Addition to 1,152,209. Heading H2A. [Also in Division Fl] In a reciprocating machine according to the parent Specification, the armature of the motor is located entirely outside the airgap at the top dead point or upper mechanical limit position; the distance between the end face of the armature and the entrance to the air gap being a maximum of 20% of the length of the air gap measured in the direction of motion of the armature. Preferably, the armature return spring has a high or variable rate and may be supplemented by an auxiliary return spring whereby, it is stated, the stroke is made more independent of the load. In one embodiment, Fig. 8, incorporated in a compressor, a piston 213 with self-lubricating rings 251 slides in a cylinder 201 having intake and delivery valves 206, 207 and has a laminated armature 215 secured to its outer end by a bolt 216 which also secures one end of a variable rate return spring 218 operating between the piston and the bottom of a casing 246 at the lower end of the cylinder. Casing 246 is formed in two halves which grip between them the laminated stator core of the motor which has a pair of opposed poles 243 carrying coils 212. Cooling air enters the casing through apertures 202. Fig. 10 shows another compressor in which a cast iron piston 166 lubricated by a wick 167 carries, in addition to the armature 169, a sleeve 289 having an external flange 172 between which and the bottom of casing 220 is located the return spring 287. An opposing spring 290 operates between the end of sleeve 289 and the head of a pin 291 secured to the casing. The compressor is mounted on anti-vibration springs 280a, 280b. A closed-circuit compressor is shown in Fig. 12, the armature 347 in this embodiment also having two springs, a main return spring 349 operating between its outer end and the magnetic core 311, and an auxiliary opposing spring 352 acting between the armature and a shoulder on the cylinder 325. The magnetic core 311 is enclosed in a casing comprising two halfshells 316 which have branches forming chambers 316 serving as an intake silencer communicating with the interior of an outer sealed casing 300 of the compressor via an intake nozzle 342 and with the cylinder 325 via a suction pipe 340. A delivery pipe 343 leads from the cylinder head to a silencer (344) which is connected to a circuit outside the casing 300 and from which a connection is taken back to the interior of the casing. The motor-compressor unit is supported inside the casing 300 by rings 355. In a further compressor, Fig. 18, the cylinder 378 forms part of the magnetic circuit of the motor, the lower part 372 carrying the coils 374 being laminated. Main and auxiliary return springs 478, 380 for the armature are arranged coaxially around the cylinder and act between the cylinder or core and shoulders on a stepped sleeve carried by the armature. The motorcompressor unit is suspended in a sealed casing 466 by springs 472. Coils 374 may be connected in series or parallel for use on different voltages. In the compressor shown in Fig. 22, the piston 413 is hollow and contains the main and auxiliary springs 418, 419. Spring 418 acts between the crown of the piston and the head 417 of a fixed rod 416 passing through the armature 414, and spring 419 acts between the head 417 and the armature. The unit is mounted on flexible arms 421 and has an intake filter 404.