US1899965A - Ignition timer breaker mechanism - Google Patents

Description

March 7, 1933. F. T. IRGENS 1,899,965

IGNITION TIMER BREAKER MECHANISM Filed May 20, 1931 2 Sheets-Sheet 1 ATTORNEYS March. 7, 1933. r F. T. IRGENS I 1,399,965

" IGNITION TIMER BREAKER MECHANISM Filed May 20, 1931 2 Sheets-Sheet 2 I ATTORNEYS Patented Mar. 7, 1933 UNITED STATES PATENT OFFICE FINN T. IRGENS, F WAUWATOSA, WISCONSIN, ASSIGNOR 'IO OUTBOARD MOTORS COR- PORATION, OF MILWAUKEE, WISCONSIN, A CORPORATION OF MICHIGAN IGNITION TIMER BREAKER MECHANISM Application filed May 20,

- outboard motorswhere the requirements of operation are such that the engine may have to operate at very low speeds for'a part of the time and at very high speeds at other times.

In order to eliminate wastage of current 2 it is desirable that the timer should be of that class in which the timing contacts are open throughout the major portion of the cycle and are closed only momentarily immediately before the break whereby the 1gnition spark is produced. If the ordinary flat sided cam is employed to operate the breaker mechanism in a timer of this class, the angular extent of the fiat surface will have to be so great at high engine speeds as to waste battery current to a very excessive degree at low engine speeds.

In order to avoid this difficulty, 2. type of breaker mechanism has long been in common use in which each rotation ofthe timer shaft trips a hammer that closes and opens the timer circuit for an interval which remains fixed irrespective of the speed of rotation of the shaft. It is found, however, that such a Y breaker mechanism is unsatisfactory when the timer is operated at high speeds. It is inadequate to function above a certain num ber of times per minute, and at speeds in excess of its capacity its failure to function causes the missing of an engine to which it is applied and thus limits the power output of the engine.

The present invention seeks, by one simple adjustment, to advance the spark in accordv ance with the engine requirements as it changes its speed of operation, while at the 1931. Serial No. 538,726.

same time gradually increasing the angle over which the breaker points or contacts are permitted to remain closed. By this means the actual time interval for which the break er points are closed may be maintained approximately constant or slowly increased or decreased at a rate distinctly different from, and even converse to, the rate of increase of rotation of the timer shaft and the engine to which it is connected.

In the drawings:

Figure 1 is a vertical axial section through a timer device embodying the invention as applied to outboard motor practice.

Figure 2 is a view taken in section in the plane indicated at 22 in Figure 1.

Figure 3 is an enlarged fragmentary detail in perspective showing the component parts of the breaker cam as viewed from be- 1 ow. V

Figure 4 is a detail view taken in section in the plane indicated by line 4-4 in Figure 1. showing the parts of the compound cam as they appear at rela ively slow engine speeds.

Figure 5 is a view similar to Figure 4 showing the same parts as they appear at relatively high engine speeds.

Figure 6 is a view similar to Figure 2 showing a modified construction embodying the invention.

E igure 7 is a view similar to Figures 2 and 6 showing a further modified embodiment of the invention. I

Like parts are identified bv the same reference characters throughout the several views In Fig. 1 I have shown the upper end of the crank case 8 and the upright crank shaft 9 of an engine such as is used on an outboard motor. The extended crank shaft bearin 10 is shouldered at 11 to receive and sup ort a sleeve 12 upon which the timer shell 15 is carried for roative t ming adjustment about the axis of shaft 9. Fly wheel 16. overh n ing shell 15 and rotatable with respect there to; provides a' closure which protects and houses the timer parts mounted on the shell including coil 17 breaker post 18. breaker arm 19 pivoted to said post. cam follower 20 on one end of the arm, insulated contact post 100 F: l I achieve the desired control of the cam through 21, and fixed and movable contacts 22 and 23 respectively.

The cam follower 2O co-acts with a compound cam whereof the component elements 5 are supported on the hub 24 of fly wheel 16.

Primary cam element 25 comprises a ring having the greater part 26 of its periphery at constant raise and reduced in thickness at 27 and 28 to provide an intervening concentric peripheral portion at 29 of sufiiciently reduced radius to permit the moving contact 23 to engage the fixed contact 22 when the cam follower 20 is traversed by this relieved cam portion 29.

The cam ring 25 is made fast to a sleeve 30. This sleeve is symmetrically provided with oppositely extending arms 31 each of which is longitudinally slotted at 32. The center lines of the respective slots are preferably approximately tangential to the inner periphery of sleeve 30, although this is not a necessary relation. The exact form and disposition of the slots will depend in any given case upon the mechanical layout necessary to means corresponding to those hereinafter to be described.

Mounted upon sleeve 30 and confined between a shoulder 34 thereon and a cam ring 25, is a sleeve 33 carrying a supplemental cam element 35 oi. limited arcuate extent. Most of the extent of cam element 35 corresponds in radius to peripheral portion 26 0t cam element 25. Near one end, however the supplemental cam element 35 is gradually reduced in radius at 36 in a manner corresponding; identically with the portion 27 or cam element 25. The extreme end portion 37 of the supplemental cam element corresponds in radius to portion 29 of the primary cam element 25.

The supplemental cam element 35 operates in an elongated arcuate notch 38 in the upper margin of the primary cam element. The shoulders at the ends of this notch limit the possible movement of sleeve 33 and supplemental cam 35 with respect to sleeve 30 and primary cam element 25. Within the range of such movement the position of sleeve 33 is controlled through curving arm 39 having arcuate slots 49 and projecting in a general tangential direction intersecting the slots 32 in the straight arms 31 which are carried by sleeve 30. Arms 39 are preferably provided at their inner ends with enlarged recesses 11 with which slots 40 comrnunicate as clearly shown in Fig. 3.

Pivot posts 4 1 projecting downwardly from fly wheel 16 serve as tulcrums for the governor weights 45. These weights have integral arms 46 extended beyond their fulcrums to receive connection with the tension springs 47. At their free ends the governor weights are provided with pins 48 which i project througi the intersecting slots 32 and neeaeer 40- in arms 31 and 39. Thus, the out-ward movement of the free ends of the governor weights about fulcrums 44 under the influence of centrifugal force, will impart rotative movement to arms 31 and 39 and the respective sleeves 30 and 33 with respect to the fly Wheel hub or any other timer shaft upon which they are mounted.

Because of the widely varying direction of slots 32 and 40, the respective sleeves 30 and 33 will move at entirely different rates in response to changes of position of the governors to a given extent. It will be noted in Fig. 2 that the dotted line position of the straight arm 31 in the extreme outward location of the governor weight is only slightly removed from the original full line position of said arm, whereas the curved arm 39 has been caused to rotate to a very substantial are between its original full line position with the parts at rest and the extreme position which is shown in dotted lines and which the parts take at maximum engine speeds.

The effect of this arrangement is to transmit motion from the outwardly moving governor weights to turn sleeves 30 and 33 both n the same d rection that shaft 9 is rotating. The motion of s eeve however, so for exceeds the motion of sleeve 30 that between the extreme positions of the governor weights the supplemental cam element 35 will be caused to move the entire length of notch 38 in the primary cam element 25. thus causing its eccentric portion 37 to move from the posi t on in wh ch it appears in Fig. 4 to the Fig. 5 position of the parts wherein said eccentric surface 37 registers with the corresponding eccentric portion 27 of the primary cam element 25.

The cam follower 20, which is preferably made of fiber in accordance with the usual practice. is so designed as to overlap both of the cam elements 25 and 35 making up the compound timer cam. Since it overlaps these cam elements it may be supported by either one or by both together. As the parts appear in Fig. 3 it will be obvious that when the left hand, end of notch 38 reaches a position of registry with the cam follower 20, the said cam follower will overhang said notch but will be supported by the high peripheral portion 26 of cam element- 25 until cam element 25 is eccentrically relieved at 27 By this time, however, the high peripheral portion of the supplemental (am element 35 will be in a position to support the follower 20., and it will not be until the eccentric portion 36 of the supplemental cam element registers with the follower 20. that the follower will be permitted to move ccntrinetally to allow contacts 22 and 23 to close. The break is always caused by the registry and engagement ot eccentric portion 28 of the primary cam member 25 with the cam follower to oscillate the breaker arm 19.

It will be obvious from the foregoing description, that the angular movement of arms closing cam 36 during the same operation of the parts will obviously regulate the relative angular distance of crank shaft rotation for which the contact points 22 and 23 will remain in engagement. Thus, by a single governor device, I control not only the timing of the spark, but also control the period of current flow, which may be made to remain approximately constant or may be varied as desired by a suitable modification of the cocentric slots 40 with which the governor pins 48 co-operate.

Experience demonstrates that a device made in accordance with this invention will overcome the difiiculties experienced in the use, on high speed engines, of previously known types of breaker mechanisms and timers. The spark produced will remain at a substantially uniformly high intensity throughout the range of operation of the device with no undue wastage of current, no missing or irregularity, and no such possibility of mechanical trouble as would exist in a more complex organization.

In Fig. 6 and Fig. 7 I have illustrated alternative means for securing somewhat simi-' lar results. In each case a compound cam is used, although in the construction shown in Fig. 6 the cam surface presented to the cam follower is continuous and uninterrupted.

In the Fig. 6 construction the timer shaft,

in this case the crank shaft 9, carries an eccentrio 50 upon which is mountedthe comple mentary eccentric cam ring 51' with a contact closlng-cam surface at 52 and a breaker cam surface at 53. The cam follower 20, breaker arm 19, and contacts 22 and 23, may correspond identically with those previously described.

Fulcrummed on posts 44 carried by the fly wheel, are governor weights 55 forced centripetally by tension springs 56 and having their free ends connected by links 57 with-a flange 58 on the-cam element 51. The centrifugal movement of the weights 55 responsive to increasing crank shaft speed s, will advance the position of cam element 51 with respect to the corresponding crank shaft position, and thus will automatically-advance the timing of the spark produced by the separation of contacts 23 and 22. At the same time, however, due to the eccentricity of 00- centric 50, the- cam surfaces 52 and 53 will recede toward the axis of the crank shaft, thereby prolonging the relative interval for which contacts 23 and 22 will remain closed.

The Fig. 7 construction is similar inmode or crank shaft 9 carries a sleeve 60 having a. i

radially projecting cam nose 61 of predetermined profile. The compound cam comprises a split ring 62 having a breaker cam portion 63 and a pivoted cam finger 64 held in engagement with the nose 61 by a spring 65 and adapted in the various positions of the split ring 62 to be adjusted to various radial settings by contact with the profile of the cam nose 61.

the cam follower 20' rides over finger 64, its position will be determined by engagement of the contacts 23 and 22 until it is again picked up by the breaker cam 63. With the parts in the position shown in Fig. 7 the interval of closed contact as measured in terms of the angular motion of shaft 9, will be short because the end of finger 64 is riding high on cam nose 61 and the follower 20 will not be dropped to a position to close contacts 23 and 22 until it has approached very closely to the breaker cam 63.

\Vhcn the weights are swung outwardly under the influence ofcentrifugal force, however, they will adjust the cam ring 62 in a direction to advance the timing by moving the breaker cam 63 in the direction of crank sentative of numerous other constructions which might be employed for the purpose. All of the devices herein disclosed, however, may be said to utilize compound cams where- -.by an automatic-timingadjustment of the parts is made more rapidly effective upon the contact closing cam than upon the breaker cam, whereby to prolong the closed contact interval in terms of the angular movement of the timer cam shaft. The device is obviously convertible by those skilled in the art for use on other types of engines and in other types of timers, the shafts of which may rotate in either direction as shown by the different direction of. rotation for which the devices illustrated on sheets 1 and 2 of the drawings are respectively designed.

1. In a timer, thecombination with relatively movable contacts and a cam follower provided with connections for the operation of said contacts, of a compound cam having relatively movable portions and angularly spaced efiective contact closing and opening surfaces subject to variation in spacing upon the relative movement of the portions of said cam, and means for varying the relative positions of said cam portions during the operation of the cam whereby to vary the closed contact interval in terms of the angular interval between said surfaces, said means being effective upon both the cam closing and cam opening surfaces to advance them at different relative rates in the direction of cam rotation and said means including a single element providing a common connection with said surfaces.

2. In a timer, the combination with a shaft, of a compound cam mounted thereon and including contact closing and contact open ing portions, one of said portions being angularly movable with respect to the other and both of said portions being angularly movable with respect to said shaft, each of said portions having an operating arm adjacent the arm of the other portion, together with a governor operated in accordance with the rotation of saidshaft and including a single element operatively connected to said ad acent arms for the angular adjustment thereof, thereby to vary the relationship between said cam portions.

3. In a timer, the combination with a shaft, of a compound timer cam mounted thereon and including relatively movable contact closing and opening portions, means for adjusting said portions whereby to vary the angular interval between the eflective surfaces thereof, said means being in adjacent relationship and relatively movable, and an automatic timer governor operatively connected by a single element with said means, thereby to vary the relative positions of said portions while advancing both thereof with respect to said shaft.

4. In a timer, the combination with a shaft, of a compound cam mounted thereon and including contact closing and contact opening portions, one of said portions being angularly movable with respect to the other and both of said portions being angularly movable with respect to said shaft, together with a Gil governor operated in accordance with the rotation of said shaft and operatively connected to said cam portions for the angular adjustment thereof, and means comprising a single element connecting the governor with said cam portions for varying the angular interval between said portions simultaneously and in predetermined ratio with their advance respecting said shaft,

5. In a timer, the combination with timer contacts and a cam follower connected to one of said contacts for its movement to and from the other, of a compound cam co-acting with said follower and including contact closing and opening portions mounted for relative circumferential movement, and means for neeaeers automatically adjusting said portions whereby to vary the angular distance between their effective surfaces, said means comprising a timer governor operatively connected by a pin to the parts of said cam for the automatic advance of said parts at different rates.

6. In a device of the character described, a compound cam having peripherally adjustable elements each of said elements being provided with an arm crossing the arm of the other, and governor means co-acting with the respective arms at their point of crossing and operable simultaneously on said arms for the related adjustment of said cam portions.

7. Ina device of the character described, a compound cam having relatively movable portions providing cam surfaces, a cam follower co-acting with said cam and operated in accordance with the interval between said surfaces, said portions being provided with projecting operating means of differing characteristics and disposed in crossing paths angularly disposed relatively to each other, and a governor operatively connected to said means at the point of crossing of said paths for the simultaneous actuation of each such portion in accordance with the character-- and provided with a breaker cam element and a breaking arm, a contact closing element rotatably mounted on said sleeve and complementary to said first mentioned element, and an arm projecting from said complementary element angularly across the arm projecting from the first mentioned element, contact mechanism including a cam follower mounted on said support and arranged to be actuated by said elements according to their relas tive angular position, and a governor weight pivotally supported from said hub and provided with means acting on said arms at the point of crossing for the differential angular advancement thereof in accordance with the rate of rotation of said shaft.

9. In a timer, the combination with a shaft, a timer support, a fly wheel co-acting therewith to provide a timer casing, said flywheel having a hub upon said shaft, a sleeve rotatably mounted on the hub, a second sleeve rotatably mounted on the first, cam elements carried by the respective sleeves, contact mechanism carried by said support and provided with a cam follower co-acting with said cam elements, oppositely projecting arms connected with the respective sleeves and provided with crossing slots varying as to angle, and governor means mounted on the fly wheel and provided with a pin extending through the registering portions of said slots and adapted differentially to rotate the respective sleeves to which said arms are connected at respectively difliering rates according to the speed of rotation of the shaft.

10. In a timer, the combination with a shaft, of an eccentric mounted thereon, a timer cam element mounted on the eccentric and provided With contact closing and breaking surface portions, a cam follower co-acting with said cam and adapted to receive motion from said portions, contact mechanism actuated by said follower, and means for angularly adjusting said cam element on said eccentricwhereby simultaneously to vary its timing and its radius with respect to said shaft.

11. In a timer, the combination with a timer shaft and contact mechanism, of a timer cam element including contact closing and contact breaking surfaces, means supporting said element from said shaft including means for varying the radial position of one of said surfaces respecting said shaft in accordance with the angular position of said element, and means for automatically adj usting said element as to its angular position in accordance with the speed of rotation of said shaft, whereby to Vary the angular interval between the effective portions of said sur faces simultaneously with the timing thereof.

12. In a timer, the combination with a shaft, of an eccentric carried thereby, a contact element rotatably mounted on said eccentric and peripherally relieved to provide contact closing and contact breaking surfaces, said surfaces being opposite a portion of said eccentric upon which said surfaces will decrease as to radius when adjusted angularly in a spark advancing direction respecting said shaft, cam follower means co-acting with said cam element and the contact mechanism actuated thereby, together with governor means rotatable with the shaft and op eratively connected with said element for the rotation thereof in a spark advancing direction about said shaft in accordance with increased speed of rotation thereof.

13. In a timer, the combination with a shaft and a cam nose mounted thereon, of a split ring between the ends of which said nose is positioned, said ring being angularly adjustable about the shaft and provided with a contact closing and a contact breaking surface, one of which comprises a finger pivoted to the ring and resting upon its nose, a cam follower co-acting with said ring and finger, contact mechanism actuated thereby, and governor means mounted to turn with said shaft and connected to act on said ring to advance it in the direction of shaft rotation in accordance with increase in rate of operation of the shaft.

FINN T. IRGENS.

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