US2386048A

US2386048A - Magneto breaker cam

Info

Publication number: US2386048A
Application number: US537896A
Authority: US
Inventors: Joseph R Harkness
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1944-05-29
Filing date: 1944-05-29
Publication date: 1945-10-02
Anticipated expiration: 1962-10-02

Description

octz, 1945. J. -R. HARKNESS VMAGNETVO BREAKER CAM Filed May. 29, 1944' 1 "@Invenbor: g JosephRHarkness,

J His Attorney Patented Oct. 2, 1945 MAQNETO BREAKER CAM i Joseph R. Harkness; Schenectadm N. Y., assignor V ,to General Electric Company, a corporation of 1 Applica'tion'May 29,

1944, Serial No. 537,896

. s claims. (01. 74-467) My invention relates-to magneto breaker cams and particularly to a cam having a large number of lobes for operating'the breaker of an' ignition system for a multiple cylinder "engine;

An object of my inventionis to provide an improved multiple lobe cam.

tion will become apparent and my invention will be better understood from the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In the drawing, Fig. 1 is an end view of a multiple lobe cam provided with an embodiment of my invention; Fig. 2 is a sectional view taken along line 22 of Fig. 1;- and Fig. 3 is an exploded perspective view of the two members which form the cam shown in Figs. 1 and 2.

Referring to the drawing, I have shown an embodiment of my improved multiple lobe breaker cam which comprises a pair of interdigitated members formed of internal supporting hubportions I and 2 with a plurality of fingers 3 and 4 extending axially from about the hub in opposite directions towards each other from the hubs. These fingers 3 and 4 are each formed with a radially raised axially extending ridge part 5 intermediatethe sides 6 of the fingers, and the two members are adapt ed to be assembled together with the ends of the fingers from one hub extending telescopically over the outer periphery of the hub of the other member between the fingers of the other member. In order to support the cam in a definite position on a drive shaft, the hub of each member is formed with a central axially splined opening with the splines I formed and arranged for axial alignment when the two members are. in assembled relationship, as shown in Figs. 1 and 2. In the manufacture of ,a multiple lobe cam of relatively small diameter, it is very diflicult and expensive to make the lobes accurately on the surface of a cam, as it requires the use of a very small grinding wheel which tends to wear away very rapidly. A cam according to my invention can be made of a relatively small diameter and is adapted to operate a single breaker for an ignition system requ ring a large number of spark discharges per revolution of the cam, and a relatively much larger size grinding Wheel can be used to form the lobes 5 than if these same size lobes were to be out on the surface of a single blank. Thus,

in'the arrangement shown in the figures each member is formed of nine fingers, an'd the assembly of the two nine-finger membersprovides a compact eighteen-lobe cam of desirable relatively" small diameter, while the f splinedf inner hub surface provides fori-a s'ecure connectionof the cam to a drive shaft while providing a sufficiently large hub section between the slots formed between the bases of the fingers and the bases of the splines to provide adequate strength to each hub. The number of fingers can be varied to provide any desired number of lobes, and the number of splines can be varied according to the diameter of the cam and the diameter of the drive shaft for the cam to providethe desired section to each hub for the required hub strength and the force to be transmitted from the shaft to the fingers.

While I have illustrated and described a particular embodiment of my invention, modifications thereof will occur to those skilled in the art. I desire. it to be understood, therefore, that my invention is not to be limited to the particular arrangement disclosed, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A multiple lobe breaker cam comprising a pair of interdigitated members each having a plurality of fingers extending axially from a supporting hub and being formed with a radially raised axially extending part on the outer surface thereof providing the lobes of said cam.

2. A multiplelobe breaker cam comprising a pair of interdigitated members each having a plurality of fingers extending axially from a supporting hub and being formed with a radially raised part on the outer surface intermediate the sides thereof providing the lobes of said cam, said members being arranged with the fingers extending towards each other from said hubs.

' 3. A multiple lobe breakercam comprising a pair of interdigitated members each having a plurality of fingers extending axially from a supporting hub and being formed with a radially raised axially extending part on the outer surface intermediate the sides thereof providing the lobes of said cam, said members being arranged with the fingers extending in opposite directions towards each other from said hubs.

4. A multiple lobe breaker cam comprising a pair of interdigitated members each having a plurality of fingers extending axially from a supporting hub and being formed with a radially raised ridge on the outer surface thereof providing the lobes of said cam, each of said hubs having a central axially splined opening with the splines formed and arranged for axial alignment when said members are in assembled relationship. I

5. A multiple lobe breaker cam comprising a pair of interdigitated members each having a plurality of fingers extending axially from about an internal supporting hub and being formed with a radially raised axially extending part on the outer surface thereof providing the lobes of said cam, said members being arranged with the fingers extending in opposite directions towards each other from said hubs and telescopically over the hub of the other of said members.

6. A multiple lobe breaker cam comprising a pair of 'interdigitated members each having a plurality of fingers extending axially from a supporting hub and being formed with a radially raised axially extending part on the outer surface intermediate the sides thereof providing the lobes of said cam, said members being arranged with the fingers extending in opposite directions towards each other from said hubs, each of said hubs having a central axially splined opening with the splines formed and arranged for axial alignment when said members are in assembled relationship.

7. A multiple lobe breaker cam comprising a pair of interdigitated'members each having a plurality of fingers extending axially from about an internal supporting hub and being formed with a radially raised ridge on the outer surface thereof providing the lobes of said cam, said members being arranged with the fingers extending in opposite directions towards each other from said hubs with the ends of the fingers of each member radially over the hub of the other member, each of said hubs having a central axially splined opening with the splines formed and arranged for axial alignment when said members are in assembled relationship.

8. An eighteen-lobe cam comprising a pair of interdigitated members each having nine fingers extending axially from a supporting hub and being formed with a radially raised axially extending ridge on the outer surface intermediate the sides thereof providing the lobes of said cam, said lfingers extending in opposite directions towards each other from said hubs.

JOSEPH R. HARKNESS.