US2086693A - Ignition control device - Google Patents

Description

July 13, 1937. J. ARTHUR 2,086,693

IGNITION CONTROL DEVICE Filed April 16, 1934 H H Ill} INVENTOR Jamez Lflrlhur:

M mgf% Patented July 13, 1937 UNITED STATES PATENT QFFICE IGNITION CONTROL DEVICE Application April 16, 1934, Serial No. 720,689

6 Claims.

This invention relates to ignition timer distributor units for internal combustion engines, and particularly to that class of ignition timer distributors having speed responsive mechanisms for 5 changing the angular relation of the cam and circuit breaker.

In constructions of this type, some difficulty has been experienced in designing a speed responsive mechanism that is sufficiently responsive to engine speeds to give the desired alteration in spark timing relation, or alteration of the angular relation between the cam and circuit breaker throughout the entire range of engine speeds.

It is, therefore, an object of this invention to control the spark-timing alteration by an if proved centrifugal device.

A further object of this invention is to increase the range of angular shift between the cam and circuit breaker.

A further object of the invention is to improve and increase the range of the angularly shiftable connection between a driven shaft and a circuit breaker operated thereby.

A further object of this invention is to increase the angular shift of a driven element with respect to a driving element by means responsive to different portions of the engine speed range, so that the total shift will be an additive result of all of the shiftable means.

Another object is to accomplish a speed-responsive control of ignition timing, characterized by advance curves of different slopes, each filling a designated portion of the entire engine speed range.

These and other objects are accomplished by inserting between the engine driven shaft and an operating cam of an ignition timer distributor unit, a centrifugal device or devices of compound form which device or devices are adapted to work independently, and together provide a control that may be somewhat overlapping in relation so as to produce a substantially continuous angular shift in the relation of driven shaft and cam,

throughout the entire range. of speeds at which the driven shaft may be actuated. Yet the controls may be assigned to separate portions of the engine speed range so that the entire spark timing control may be caused to coincide with any particular spark timing curve even though the curve may be composed of branches of different shape.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

Fig. l is a vertical section of a timer distributor unit disclosing the instant invention.

Fig. 2 is a similar vertical sectional view illustrating a modification of the instant invention.

Fig. 3 is a sectional view substantially as illustrated by the line and arrows 3-3 of Fig. l, and which illustrates the speed responsive mechanism in plan.

Referring particularly to Fi 1 of the drawing, 20 and 2! designate ignition timer housing members of superimposed cup-like form, that are socured together by appropriate screws 22. The housing members thus assembled provide a chamber 23 within which is housed a centrifugal device 2 that has aligned bearings 25 and 26 in the superimposed bottom walls 2i and 28 respectively of the cups 2i] and 2!. A distributor cap 23 cooperates with the cup 2! to provide a circuit breaker housing 36, and the bottom of the cup 23 provides a shank 31 within which is formed a bearing 25 by means of a sleeve 32.

Within the circuit breaker housing 35) there is mounted a circuit breaker 33 that is actuated by an appropriate cam 34 from a cam carrying shaft 35 joining one of the elements of the cen trifugal device 24. Inasmuch as this invention does not pertain in detail to the. circuit breaker mechanism, or the cam for operating the same it is deemed that further description thereof is unnecessary since characteristics of the same are well known to those experienced in the art. Suffice it to say, then, that the circuit breaker 33 is appropriately supported by one or more plates 35 secured to the bottom of the housing member 2 i, in position to be actuated by the cam 34 upon rotation thereof.

The housing member 20 is of conventional design insofar as it includes the shank member 3| adapted to be set into an aperture of the engine base, where gear connection is made for rotating the shaft assembly provided by the timer distributor unit. This shaft assembly includes a driven shaft 31 fitted with a pinion 38 to mesh with the engine driven gear, the shaft 31 being journaled within the bearing sleeve 32 and of such extent as to project upwardly into the chamber 2:3, slightly above an extension 36 forming a bearing boss in the bottom of the housing member 20 coextensive with the shank 3|.

Means are provided in the bottom of the housing member 20 for lubrication of the driven shaft, and includes a chamber 39 closed off by an expanded plate 48 that frictionally engages the bearing boss 38 and a wall of the cup member 20. A grease-fitting 4i provides for applying a lubricant to the chamber 39, and a lateral bore 32 allows the. lubricant to continue to to find its way through the bearing boss 33 and a bearing sleeve 35. where it comes in contact with the surface of a driven shaft 31.

The centrifugal controlling mechanism, by which the instant in ention is accomplished, provides an angularly shiftable connection between the driven shaft 3? and the cam carrying shaft 35, and is characterized substantially as herein follows. The distributor end of the driven shaft 31 is provided with an axial bore 35 and has a cam bar 4E2 fixed at the terminal end projecting above the bearing boss 35. One or more spacers or shins ll, 28 are disposed between the cam bar 45 on one side and the end of the bearing boss 38 and the bearing sleeve 32 on the other side. An intermediate shaft 39 is piloted, or has bearing surfaces engaging within the bore 65, and has affixed thereto a weight carrying plate in which are secured pivot posts 5! and 52. The pivot posts of substantial length, both above and below the weight plate 55, and pivotally support elements of the centrifugal device.

In the illustrated embodiments, two such centrifugal devices are provided, one of which constitutes the flyweights and 5-2 supported on the lower end of the pins 5! and 52 by appropriate clips or spring rings so that the fiyweights may easily be pivoted upon the respective pins. A second pair of flyweights 55 and 5'! are carried by the pivot pins 5i and 52, and are disposed on the upper side of the weight plate Inasmuch as both sets of centrifugal devices are substantially identical form, the detailed description of one set is thought to be sufrlcient. Reference is therefore made to Fig. 3, wherein the upper set of fiyweights is shown. In the form illustrated, the weight members are made up of several laminations at least one of which includes a lever arm 55a or 57a as the case may be that forms a cam bearing surface engageable with a cam surface of the respective cam bar.

As for the upper centrifugal device, the cam bar is designated at 58, and is mounted upon the lower end of the cam carrying shaft 35 whose reduced end is piloted within a bore 68 of the intermediate shaft. Engagement between the cooperating cam surfaces is maintained by ap propriate springs 5! that are hooked to the notched ends of the pivot posts ill and 52 and to notched ends of spring posts secured in the respective bars. With respect to the lowermost centrifugal device, the spring posts 52 and 63 are secured in the cam bar as illustrated, the spring post 63 being extended as at 64 to project into an aperture 55 of the weight plate Considering the upper centrifugal device, the spring posts 66 and 5? are carried by the cam bar 58, the spring post 56 having an extension 65a that projects into an aperture 58 of the weight plate 58. The apertures of the weight plate are sufi'lcient in extent to allow lateral movement of the extended spring posts, and so as to mark the limits of relative movement between the weight plate-and each of the cam bars. Thus the extended posts cooperating apertures form stops for the inward and outward movement of the fly-weights.

As appears in 3, it will be observed that when the springs 6i are hooked to the posts 5|, 66 and 52, 61, the tension of those springs will cause the weights 56 and 51 to be urged inwardly toward the center of the centrifugal assembly, and in doing so will be caused to ride over the ridges 69, which reduce the friction of their movement.

It will be appreciated that upon rotation of the driven shaft 37, that a driving connection will be afforded between the cam bar 46 and the flyweights 53 and 54 to the intermediate shaft, and that the driving force will thence be transmitted from the weight support 50 through the fiyweights 56 and 51 to the cam bar 58, and thence to the cam carrying shaft 35. Due to the rotation of this assembly, or due to the centrifugal force applied to the flyweights 56, 51 and 53, 54 an angular shift is obtained in the relation of the cam carrying shaft 35 with respect to the intermediate shaft 49, and in the relation of the intermediate shaft with respect to the driven shaft 35.

Each set of weights may be so characterized, and the spring Bl maintaining the cam surfaces in engagement may be predetermined to such an extent, that one set of weights will respond to engine speeds at the lower end of the engine speed range, while the second set will be responsive only to some other portion of the engine speed range. Following after this thought, it is desirable to so apportion the characteristics of the centrifugal devices that they may be responsive to, and effective throughout substantially the entire range of engine speeds. As an example, one part of this speed responsive mechanism may produce an angular shift throughout the lower half of the engine speed range, while the second part of the speed responsive mechanism may produce an angular shift throughout the upper half of the engine speed range.

In so apportioning the speed responsive control, it may be desirable that the speed responsive mechanisms overlap slightly, so that the spark advance curve will amount to a substan tially continuous slope. Again, it may be desirable to apportion the control by one speed responsive mechanism to a small portion of the engine speed range so as to produce a spark timing curve of a definite slope, and thence apply the other speed responsive mechanism so as to produce a spark timing curve of a decidedly different slope. apply the speed responsive controls, one each for a small and different portion of the speed range, at or throughout the extremes only of the entire speed range, and separated by an intermediate portion of the speed range that is not subject to speed responsive control. The particular desired application of the speed responsive control can be accomplished by apportioning the mass of the flyweights, the pulling force of the springs, and the size and position of the stops.

Having this in mind, then it will be appreciated that the operation of the device is somewhat as follows. Assuming for the purpose of illustration that the lowermost set of flyweights is responsive to engine speeds throughout the lower portion of the engine speed range, and that the upper set of flyweights is responsive to engine speed throughout the upper portion of the engine speed range, and that in the particular instance the weights and contributing elements will be so apportioned as to provide a gradual and continuous control throughout the entire engine speed range, that is the control of one slightly overlapping at its one end the control by the other; rotation of the engine driven shaft 31 will Again, it may be desirable to" secured to the shaft 35.

drive the cam bar 36 whichin turn will drive the weight plate 50 through the cam engagement between the bar 46 and the cam arm of the weights 53 and 54. As the speed of rotation of the shaft 31 increases throughout the lower portion of the engine speed range the flyweights 53 and 54 will move radially from the axis of the assembly and in so doing act upon the cam bar 46 to cause an angular shift between the intermediate shaft 49 and the driven shaft 31.

This angular shift will be manifest in the lower range of engine speeds, or within the range of change that is permitted by reason of the stop provisions 64 and 65. Driving of the intermediate shaft and the weight plate 50 provides for driving the cam carrying shaft 35 through the fiyweights B and 51 having camming engagement with the cam bar 58. In the hypothetical structure assumed, when the centrifugal assembly is driven beyond the lower portion of the engine speed range, the flyweights 56 and 51 will be ineffective to produce any change in angular relation of the shaft elements 49 and 35, but will produce an angular shift therebetween as the engine operating speed reaches the upper portion of the engine speed range. In other words, at or about the point that the flyweights 53 and 54 cease to produce any angular shift between the shaft elements 31 and 49, the fiyweights 56 and 51 begin to operate so as to accomplish an angular shift between the shaft elements 49 and 35, so

that there may be an uninterrupted change in angular relation between the shaft elements 31 and 35.

It will of course, be appreciated, that any change produced upon the shaft 35 is also communicated to the cam 34 inasmuch as the cam 34 is rigidly In the illustrated embodiment, this is accomplished by providing the end of the shaft 35 with a plurality of expansible tongues adapted to be crowded into engagement with the central bore of the cam 34 by aid of a conical or wedgelike member 16 carried by screws 18 and threaded into the end of the shaft.

Where the equipment is to be used in the extremely highspeed automotive engines it is desirable to insure perfect operation of the weights, especially those responsive to: the higher speeds. In the present embodiment these improvements concern a weight guide plate 19 that provides a pair of oppositely extending arms 80 extending radially from the center of the assembly substantially over the friction ribs 69, and spaced therefrom s o as to act somewhat as keepers. It is also desirable to insure the driving connection between the cam carrying shaft 35 and the cam bar 58 against any relative angular movement. Cross pins 8| are, therefore, passed through the lower end of the cam carrying shaft 35 so as to engage on either side the spring posts 66 and 61. A fibrous washer 82 is also carried by the cam carrying shaft 35 that has communication with an axial bore 83 in the shaft element 35 through which lubricant finds its way for reducing friction between the movable parts of the centrifugal assembly.

The invention is substantially the same in the embodiment of Fig. 2 as in Fig. 1, in that an angularly shiftable connection is provided between the driven shaft 3'! and the cam carrying shaft 350., which angularly shiftable connection responds to the desired portions of the mechanism controlled by the engine speed range. The essential difference or differences lie in the configuration of the intermediate shaft and the cam carrying shaft, for here the intermediate shaft 49 extends laterally on each side of the weight plate 50. One end of this shaft is piloted within the driven shaft 31 as hereinbefore described, but

the upper end 49a forms a pilot about which the tubular cam carrying shaft 35a is rotatable. The cam bar 58 is mounted upon the lower end of the cam carrying shaft 35a, and has its connection with the weights of the centrifugal devices as has hereinbefore been described.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

I claim:

1. An ignition timer comprising, in combination, a circuit breaker and a cam for actuating the breaker, an engine driven shaft, speed responsive means coupling the shaft to the cam and adapted to alter the angular relation between the shaft and cam, said means including an intermediate shaft piloted for relative angular movement with respect to the cam and to the engine driven shaft, a weight plate secured to the intermediate shaft, a plurality of sets of centrifugal devices carried by the plate, pivot posts secured in the plate providing common pivots for weights of each device, a cam bar fixed to the driven shaft, a second cam bar fixed in relation to the cam, and means providing a yieldable driving connection between each of the bars and one of the sets of centrifugal devices, each set of centrifugal devices being severally operative to effect independent shifts between the cam and the engine driven shaft.

2. An ignition timer comprising, in combination, a circuit breaker and a cam for actuating the breaker, an engine driven shaft, speed responsive means coupling the shaft to the cam and adapted to alter the angular relation between the shaft and cam, said means comprising an intermediate shaft and weight plate piloted for oscillatable movement within an axial bore of the driven shaft, a cam carrying shaft piloted for oscillatable movement within an axial bore of the intermediate shaft, and a pair of centrifugal devices carried by the weight plate for drivingly connecting the driven shaft with the intermediate shaft and the intermediate shaft with the cam carrying shaft, and common pivot posts for the weights of each device projecting from both sides of the plate one of said centrifugal devices responding to a lower range of shaft speeds than the other centrifugal device.

3. In an ignition timer having a circuit breaker and a cam for actuating the circuit breaker, speed responsive mechanism for controlling the angular relation of the circuit breaker and cam, comprising in combination, an engine driven shaft, a cam bar carried by the driven shaft, a cam carrying shaft, a cam bar carried by the cam carrying shaft, an intermediate shaft rotatable with respect to either or both the driven shaft and the cam carrying shaft, a weight plate secured to the intermediate shaft and interposed between the cam bars, a plurality of weight devices carried by the plate, means providing coincident pivots for the weights of each device and means maintaining the weight devices in yieldable engagement with both of said cam bars one of said weight devices effecting an angular shift between the engine driven shaft and the weight plate, and another of said weight devices effecting an-angular shift'between the weight plate and the cam carrying shaft.

4. In an ignition timer having a circuit breaker and a cam for actuating the circuit breaker, speed responsive mechanism for controlling the angular relation of the circuit breaker and cam, comprising in combination, an engine driven shaft, a cam bar carried by the driven shaft, a cam carrying shaft, a cam bar carried by the cam carrying shaft, an intermediate shaft rotatable with respect to either or both the driven shaft and the cam carrying shaft, a weight plate secured to and rotatable with the intermediate shaft, pivot pins extending through the plate, centrifugal devices pivoted on one end of the pins and operatively connecting the driven shaft with the intermediate shaft and responding to predetermined engine speeds at one end of the engine speed range for Varying the angular relation between the cam and circuit breaker, additional centrifugal devices pivoted on the otherend of the pins and operatively connecting the intermediate shaft with the cam carrying shaft and responding to engine speeds other than the predetermined engine speeds for further varying the angular relation between the cam and circuit breaker.

5. In an ignition timer, having a circuit breaker, a cam for operating the breaker, and an engine driven shaft for actuating the same, means for varying the angular relation between the circuit breaker and cam, comprising, a cam bar carried by the driven shaft, a weight plate and shaft piloted for oscillation with respect to the driven shaft, a cam carrying element with a cam bar piloted for oscillation with respect to the second shaft, a plurality of centrifugal devices carried by the weight plate and situated above and below the same, and pivoted upon the same pins carried by the plate, means resiliently urging the centrifugal devices into engagement with the cam bars each of the centrifugal devices responding to different portions of the entire speed range of the engine driven shaft, and one of the centrifugal devices becoming effective to shift the respective parts at the high speed end of the speed range for the other centrifugal device.

6. In an ignition distributor having a driving shaft and a cam driven thereby, in which the cam is angularly displaceable with respect to the driving shaft upon changes in speed of driving shaft 1 rotation, the combination of means drivingly connecting the driving shaft with the cam comprising, a weight plate and stub shaft pivoted and having a bearing surface within the body of the driving shaft, symmetrically disposed on the weight plate and operatively connecting the driving shaft to the weight plate so as to effect an angular displacement between the weight plate and driving shaft throughout substantially the lower half of shaft speeds for the entire speed range, said cam having a pivot and bearing extending within the stub shaft of the weight plate, and a second set of weight devices carried by the weight plate and operatively connecting the Weight plate to the cam extension and symmetrically disposed so as to effect angular displacement between the weight plate and cam extension over substantially the upper half of shaft speeds of the entire range of shaft speeds, said weight devices being but slightly overlapping at the upper end of the low speed range and the lower end of the high speed range so as to effect substantially continuous angular displacement of the cam relative to the driving shaft throughout the entire range of driving shaft speeds, and both of said weight devices being symmetrical and their elements being diametrically disposed so as to maintain a condition of balance of the centrifugal devices throughout the entire speed range of the driving shaft and cam.

JAMES L. ARTHUR.

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