US2256292A - Ignition apparatus for internal combustion engines - Google Patents

Description

Sept. 16, 1941. F. R. F. RAMSAY IGNITION APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed March 30, 1940 m P, E W

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Patented Sept. 16, 1941 IGNITION APPARATUS FOR INTERNAL COM- BUSTION ENGINES Frank Raymond Faber Ramsay, London, England, assignor to D. Napier & Son Limited, London, England, a company of Great Britain Application March 30, 1940, Serial No. 326,992

In Great Britain April 13, 1939 v 9 Claims. This invention relates to energising apparatus for supplying low tension current impulses to the primary winding of a high tension magneto of an internal combustion engine to facilitate starting.

For this purpose it has been proposed to provide a primary circuit comprising a battery and an interrupter of the buzzer type with switches for closing the primary circuit and connecting it to the primary winding of the magneto during starting. It is convenient to construct the energising apparatus and the switches controlling it as a unit and in prior proposals this has meant in practice that this apparatus must be arranged near the pilot or other person responsible for the control of the engine. This is, however, not always either convenient or desirable and the object of the present invention is to provide an improved arrangement which may be applied to the previously proposed apparatus referred to above, or to other apparatus of the kind referred to, for example the apparatus forming the subject of the present applicants copending United States of America Patent application Serial No. 269,256, which will enable the energising apparatus to be disposed at a distance from the point of control, for example near the engine or magneto. To this end in energising apparatus of the kind referred to for supplying low tension current impulses to the primary winding of a high tension magneto of an internal combustion engine according to the present invention, there is combined with a primary circuit including an interrupter and adapted to be connected to a source of current, an electromagnetically operated switch which controls the connection between the energising apparatus and the primary winding of the magneto and is adapted to close automatically when the primary circuit is energised and to open automatically when this circuit is deenergised.

Thus, a switch for closing the primary circuit may be provided adjacent to the point of control, while the energising apparatus itself, including the switch for connecting it to and disconnecting it from the primary winding of the magneto, may be disposed at any desired point. I

Where, as will generally be the case, an interrupter of the buzzer type is employed, the electromagnetically operated switch may be actuated by the stray-field from the coil of the buzzer. Thus, for example, the interrupting contacts of the buzzer may lie at one end of the core of the lies at the other end thereof. In this case the coil conveniently has an open-ended core with a strip of metal constituting a magnetic link extending between but separated by gaps from the ends of the core for the purpose of concentrating the stray field.

In any case, the movable contact of the electromagnetically operated switch is conveniently of such weight that when the coil is energised it will maintain the eelctromagnetically operated switch permanently closed in spite of the interrupted nature of the current flowing through the primary circuit. For example, the electromagnetically operated switch may comprise a comparatively heavy armature mounted upon a metal leaf which carries, preferably resiliently, two contacts insulated from one another and adapted to engage two fixed contacts, when the coil is energised so as to connect the energising apparatus to the primary windings of two magnetos.

In such a case the armature is preferably connected to the metal leaf in such a manner that it can rock relatively to the leaf to a suflicient extent to enable the armature to bed properly upon the end of the core of the coil without materially distorting the leaf. Thus the armature may be connected to the leaf at a single point, in which case the armature can rock relatively to the leaf in all directions without materially distorting it or may be connected to the leaf so that it can rock relatively thereto only in one direction, e. g. about a line at right angles to the length of the leaf. In this way, buzzing of the armature due to its not bedding down properly on the core with the result that the armature tends to rock about the point at which it engages the core and thus to distort the leaf, tends to be prevented.

The invention may be applied to apparatus for use with a single magneto or for use with two magnetos associated with a single engine and two arrangements according to the invention as applicable to two magnetos are illustrated diagrammatically by way of example in the accompanying drawing, in which Figure 1 shows one arrangement as applied to two magnetos of an engine in which the magnetos supply alternate sparks,

Figure 2 shows an arrangement as applied to two magnetos of an engine in which the magnetos supply simultaneously sparks,

Figure 3 is a somewhat diagrammatic side elevatior of a combined interrupter and electromagnetically controlled switch of the kind employed in the construction shown in Figure 2, and

coil while the electromagnetically operated switch Figure 4 is a diagrammatic plan of the construction of switch diagrammatically shown in Figure 3.

In the construction diagrammatically shown ondary winding D of a transformer D. The primary winding D of the transformer D is arranged in a primary circuit D including a battery E and an interrupter F of the buzzer type operated by the stray field from the transformer D, this circuit being controlled-by a manually operated switch G.

Arranged in parallel with the primary winding D is the operating coil C of the switch 0 which when energised is arranged to close the switch.

The operation of the apparatus is as follows. When the switch G is closed the coil C and the primary winding D are energised. The interrupter F thus comes into operation and simultaneously the switch C is closed to connect the two magneto primary windings A and B to the secondary winding D of the transformer D. Since the two magnetos A and B supply alternate sparks the contact-breaker of one magneto is always closed when that of the other opens. The closed contact-breaker thus earths one end of the secondary winding D and thus completes the circuit through this winding and the primary winding of the other magneto. In this way as long as the switch G is kept closed a series of low tension current impulses are delivered to the primary winding of whichever of the two magn'etos at any moment has its contact-breaker open. When the engine has been started, the switch G is released, whereupon the switch 0 opens to break communication between the magnetos and the energising apparatus.

It will be seen that the energlsing apparatus (constituted by the apparatus enclosed in a dotted line) 1 can be arranged and constructed as a unit which can then be coupled to the battery E and switch G by a pair of conductors and to the magnetos by a further pair of conductors. Further these latter conductors may be the same as the normal earthim; conductors leading to the usual ignition switch.

In the alternative construction illustrated in Figure 2 the magnetos A and B are of the same conventional type as shown in Figure 1 but are adapted to supply simultaneous sparks. To this end the conductors A, B are adapted to be connected through switch apparatus H respectively to opposite ends of the secondary winding J of a transformer J, the centre of this winding being earthed as shown. In this construction, as in theconstruction shown in Figure 1, the primary winding of the transformer J is arranged in a primary" circuit including abattery K and an interrupter K of the buzzer type operated by the stray field from the transformer, the primary circuit being controlled by a manually operated switch L.

Inlthis arrangement the switch H'for coupling the secondary winding J to the magnetos A and secure'by Letters Patent is:

B is also arranged to be operated by the stray field from the transformer J. To this end the switch H comprises a spring leaf M anchored at M and carrying at M an armature of such weight that when drawn into contact with the end of the core of the transformer J it will remain in contact therewith in spite of the intermittent nature of the current caused by the interrupter K as shown connected to the leaf M at a single point so that it can rock to a small degree without materially distorting the leaf and can thus readily bed down on the end of the transformer core. Also carried by the leaf M but insulated therefrom are two contacts M, M connected by flexible leads M respectively to the conductors A and B" and adapted when the transformer J is energised to engage contacts M, M connected respectively to opposite ends of the winding J Also arranged in the circuit of the battery K and arranged to be closed by the switch L is the operating coil of an electromagnetic. switch 0 arranged to bring an electric engine starter into operation.

The operation of the apparatus shown in Figure 2 is as follows. When the switch L is closed the primary windingof the transformer J is enrgised, the interrupter K comes into operation, the switch H is closed and hence a series of low tension current impulses are transmitted through the conductors A and B from the secondary winding J to the primary magneto windings. At the same time th switch 0 is closed to bring the electric starter into operation and hence cause rotation of the engine crankshaft. Starting of the engine is thus effected whereupon the 'switch L is opened and the engine continues to operate in the normal way.

In this construction also it will be seen that only two leads are required to the energising apparatus (enclosed in a dotted line) from the battery and switch L and only two leads from this apparatus to the magnetos.

Figures 3 and 4 show still somewhat diagram- 1 matically how the combined transformer J, interrupter K and switch H may be constructed. Thus it may comprise a. casing -P in which the transformer proper is disposed with the ends J, J of the transformer core projecting from opposite ends of this casing. Disposed adjacent to the end J of the core is a spring-mounted interrupter armature K" carrying a contact K normally making contact witha contact K on a spring leaf K the contacts K K3 thus constituting an interrupter of the buzzer type in the circuit of the primary winding of the transformer. 7 Disposed adjacent to the end J of the core is the armature M supported on the spring leaf M. In this construction howevenli'nstead of the contacts M, M being directly carried by the leaf M they are carried by separate leaves M M arranged to be acted upon by a stripof insulating material M secured to the leaf M. Actually the opposite ends of theswinding J 'shown dotted in the left half of Figure 3, are

connected as shown in Figure 2 respectively to two contacts M', M arranged one behind the other in this figure and arranged to make contact respectively with the contacts M- and M as in Figure 2, as previously described. 7

What I claim as my invention and desire to 1. Energising apparatus for supplying low tension current impulses to the primary winding ofa high tension magneto of an internal combus- In order to assist this the armature M is tion engine, comprising a primary circuit including an interrupter and adapted to be connected to a source of current, and an electromagnetically operated switch for controlling the connection between the energising apparatus and the primary winding of the magneto arranged to close and open automatically as the primary circuit is respectively energised and deenergised.

2. Energising apparatus for supplying low tension current impulses to the primary winding of a high tension magneto of an internal combustion engine, comprising a primary circuit includingan interrupter of the buzzer type arranged to be connected to a source of current, an electromagnetically operated switch for controlling the connection between the energising apparatus and the primary winding of the magneto arranged to close and open'automatically as the primary circuit is respectively connected to and disconnected from the source of current.

3. Energising apparatus as claimed in claim 2, in which the electromagnetically operated switch is actuated by the stray field from the coil of the interrupter.

4. Energising apparatus as claimed in claim 2, in which the interrupting contacts constituting the buzzer lie at one end of the core of the coil while the contacts of the electromagnetically operated switch lie at the other end thereof.

5. Energising apparatus as claimed in claim 2, in which the primary circuit includes the primary winding of a transformer, the secondary winding of which is arranged to be connected to the primary winding of the magneto by the electromagnetically operated switch.

6. Energising apparatus as claimed in claim 2, in which the interrupter is operated by the stray field from a transformer the primary winding 01' which lies in the primary circuit while the secondary winding is arranged to be connected to the primary winding of the magneto by the electromagnetically operated switch.

7. Energising apparatus as claimed in claim 2, in which the electromagnetically operated switch comprises an armature arranged to be drawn into contact with a core when the latter is magnetised electrically and of such weight as to remain in contact therewith as long as the primary circuit is connected to the source of current in spite of the interrupted nature of the current in that circuit.

8. Energising apparatus as claimed in claim 2, in which an armature is operated by said switch and is carried by a spring leaf whereby the switch contacts are directly or indirectly moved.

9. Energising apparatus as claimed in claim 2, in which an armature is operated by said switch and is mounted on a spring leaf so as to be capable of limited rocking movement relatively thereto without materially distorting the leaf so as to iacilitate the bedding of the armature on the core.

FRANK RAYMOND FABER RAMSAY.

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