Patent GB-255449-A (GB)
Title: Improvements in or relating to starting mechanism for internal combustion engines
IPC: F02N11/08
Filed: 1926-07-12
Abstract: 255,449. Trail, H. H. July 14, 1925, [Convention date]. Starting prime movers. - A manually-operated switch A for an electric starter has normally open contacts 36, 37 closed by an arm 38 for initiating the starting operation, a pair of normally closed contacts 41, 42 automatically separable by variation of fluid pressure caused by rotation of the engine to be started, and means for positively holding the contact 42 in the open position when moved by fluid pressure. As shown, the contact 42 is carried by a spring-pressed piston in a cylinder 43 connected to the engine induction system or to the oil circulation system. When the engine starts and the contact 42 is moved by the engine suction or oil pressure, a shoulder 46 on the contact 42 is engaged by a spring arm 45 on the switch lever as long as the switch arm 38 remains closed. The switch contact 36 is connected at 50 to the generator windings of the starting motor 3, and the contact 37- is connected to the ignition circuit 52 of the engine and to an electromagnet 22 adapted to operate a make-andbreak device 26 in circuit with the starting-motor 3, to close a switch 56 in circuit with the electromagnet. and to cause axial movement of a starter pinion 6 into engagement with an engine member 55, the return movement of the pinion being adapted to open the switch 56 and so de-energize the electromagnet. The pinion 6 is threaded to engage a screw-threaded sleeve 4 secured to the armature shaft 2, and is normally held in the position shown by a catch 8. Axial movement of the pinion is effected by a lever 12 connected by a link 16 to the core 21 of the electromagnet. When the switch A is on, current from the battery 47 passes to the ignition circuit and also through the electromagnet and by a conductor 54 and contacts 41, 42 to earth. Current also passes by way of the contacts 36, 50 to the generator windings, and by a conductor 51 and contacts 31, 28 to earth at 27, the contact 28 being carried by a lever 26 normally held in the position shown by a spring 30. The motor is thus turned slowly, and the movement of the electromagnet core 21 shifts the pinion 6 into engagement with the engine member 55. A contact 56 on the electromagnet is then engaged and earthed by the lever 12, and a member 24 on the spindle 20 of the core 21 engages a projection 25 on the lever 26, separating the contacts 28, 31 and closing contacts 29, 33, so that the battery current is now supplied to the motor windings through a connection 59, and terminal 60, commutator 34, and conductor 61. The contact 42 is separated from the contact 41 by engine suction &c. and held by the spring arm 45. At the same time, the pinion 6 is automatically disengaged by the screwed sleeve 4 and re-engaged by the catch 8, so that contact is broken between the lever 12 and contact 56. In a modification, the generator windings and corresponding connections are omitted. Specification 244,978 is referred to. The Specification as open to inspection under Sect. 91 (3) (a) states that the spring arm 45 may be omitted, so that stoppage of the engine will allow the contacts 41, 42 to close and cause automatic actuation of the motor for re-starting the engine. This subject-matter does not appear in the Specification as accepted.