US1725522A - Ignition-governing apparatus - Google Patents

Description

Aug. 20, A. KENT IGNITION GOVERNING APPARATUS Filed June 25. 1921 2 Sheets-Sheet l WUZ I mi ATTORNEY.

Aug. 20, 1929.

A. A. KENT IGN'I TI ON GOVERNING APPARATUS Filed June 25, 1921 2 Sheets-Sheen 2 65 who who 2000 nice eooa zA/qwvz SPEED INVEN TOR.

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Patented Aug. 20, 1929.

ARTHUR ATWATER KENT, F ARDMORE, PENNSYLVANIA.

IGNITION-GOVERNING APPARATUS.

Application filed June 25, 1921. Serial No. 480,315.

My invention relates to apparatus for automatically governing the production of ignition sparks for internal combustion engines, particularly a variable speedengine such as employed upon motor vehicles, or in like relations.

In accordance with my invention, there is utilized a centrifugal or automatic gover-' nor of very small weight, mass or inertia, particularly as to the governor late or member, and the weights carried solely thereby, secured to the system, comprising an ignition-timing cam or equivalent and the usual distributor, for angularly adjusting that system, in response to speed changes, with respect to the engine driven or timer shaft to which latter the other of the governor plates or members is' secured, and with which the cam and distributor system is coaxial. r

In accordance with my invention, the cam and distributor system has a mass, weight or inertia which is so large a proportion of the mass, weight or inertia of that system and the thereto attached governor plate and weights, that, throughout the range of angular adjustment of the system with respect to the timer shaft in response to changes of speed of' that shaft, the adjustment is smooth and regular, and overcomes the erratio or irregular behavior which characterizes the same structure but with the weightciilrrf'ying governor plate secured to the timer s a t. For an illustration of one of the various forms my invention may take, reference is to be had to the accompanying drawings, in.

which:

Fig. 1 is a plan view of interrupter structure. c

Fig. 2 is a verticalsectional view on the line 2-2 of Fig. 1. A

, Fig. 3 is a top plan view of structure shownin Fig. 2 with the top plate removed. Fig. 4 is an inverted plan view of the governor structure shown in Figs. 2- and 3.

Fig. 5 is a perspective view of the system comprising the timer cam or. equivalent with attached weight-carrying governor plate. 0 Fig. 6 is a persplective view of the driving I or timer shaft wit attached co-acting governor plate.

Fig. 7 is a perspective view of one of the governor weights.

Fig. 8 is a sectional view illustrating the integral punched pivot.

Fig. 9 comprises characteristic curves explanatory of my invention.

Referring to the drawings, 1 is a'metallic casing having an integral machined cylindrical hub, 2 whereby the structure is supported and capable of rotation in a suitable supporting member, not shown. The hub 2 is bored to provide bearings for the engine driven or timer shaft 3 having at its lower end the tongue or lug 4 whereby the shaft 3 .is driven by and in suitable fixed relation with the internal'combustion engine whose ignition is controlled by the shaft 3. The speed of the shaft 3 is generally half that of the crank shaft of the engine when the latter is of the four cycle or four stroke typp.

Rigidly secured to the shaft 3, as y shrinking it thereon, is the smaller, lighter, or secondary governor plate 5, in this instance shown as stamped from sheet steel of suitable thickness. In the periphery of the plate 5 is a plurality of notches or recesses 6, preferably uniformly circumferentially spaced. Integral with the plate 5 is the upstanding lug 7 hereinafter referred to.

, The shaft 3 at its upper end is reduced in diameter to for'm the bearing member 8 for the sleeve 9, integral with which or upon which is secured the cam 10 having as many points as there are cylinders of the engine; in the example illustrated, the cam is suited for a four-c linder engine. The sleeve member 9 exten s freely through an opening 11 in the plate 12 secured upon the upper edge of the casing 1. Secured upon the plate 12 is the bracket 13, to which is secure a leaf spring 14 which supports the movable interru ter arm 15 having the fibre shoe or cam f0 lower I6 actuated by the cam 10 as it rotates to move the movable interrupter contact 17 away from the stationary interrupter contact 18, the spring 14 returning the contact 17 into engagement with the contact 18 as and whenpermitted by the cam 10. The interrupter contacts are shunted by a condenser contained in the structure 19.

The cam sleeve 9 is slotted at its upper and a 2 to receive and drive the high tension distributor, not shown, as well understood in the art. I

Rigidly secured to the cam sleeve 9, as

-by shrinking it thereon, is the main or material and construction.

primary governor plate 21, of any suitable In the example illustrated the plate 21 is stamped from sheet steel of suitable thickness. Upon each of .a suitable number of pivots 22 is pivoted a movable arm or governor weight 23 having an inwardly projecting arm 24 having a rounded end 25 engagin in a notch 6 of the secondary governor p ate 5. In the example illustrated, each governor weight 23 is formed of sheet metal andbent'to U- shaped form as indicated at 26, Fig. 7, whereby each weight 23 embraces the edge of the governor plate, 21 To the ear 27 of each weight member 23 may be attached at a hole 27 in car 27 one en'd of a sprlng 28, whose other end is attached to the plate 21 at a hole 29 therein.

While each governor weight may be provided with a spring, as stated, I have found...

. the notch, aperture or other suitable formation 30 in the plate 21, the lug 7 being bent over the plate 21, thereby preventing separation of .the plates 5 and 21 from each other'in a direction longitudinallyof the axis of rotation of the shaft 3. The angular extent about the axis of the shaft 3 of the notch 30 is made such as to permit sufficient angular movement of the plate 21 with respect to the plate 5 and shaft 3 and yet limit such angular adj ustinent'or movement.

'lVhile at 22 separate pivot pins may be provided, it is preferred, as indicated in Fig. 8, that the pivots 22 shall be integral with the plate 21 and formed by placing the plate 21 over a die member 31 having therein a circular hole of the diameter which the pivot s to have. There is then brought down upon the plate 22 by any suitable means a: punch 32 which is forced-only part way through the plate 21, forcing out into the hole in the die member 31 the integral pivot 22. By preference the punch 32 has a diameter greater than that of the pivot 22. to be formed, whereby without passing too far through the plate 21 the unch 32 displaces suf iicient metal to form t e pivot 22 of suffiClOIlildlEtIIlBtGI and height or length below .the surface of the plate 21. The pivot 22 is in effect a punching from the plate 21 which has not been completely dislodged or severed therefrom, but remains in part within the plate. in the process of formation, and its attachment to the plate 21 is more firm and secure than in the case of separate inserted pivots. Pivots formed as described have the advantage that they do not work or jar loose in service, as is the case with inserted pivots. Furthermore, by the structure described the The pivot itself is hardened cost of production is materially decreased.

. The operation isas follows:

As the shaft 3 is driven or rotated bythe engine in fixed angular relation with respect to the engine shaft, the governor plate 5 is rotated at like speed. Rotation is communicated to the arms 24 of the governor weights and through them to the governor plate 21, with which rotates the sleeve 9 and there fore the timing cam-10 and the distributor, not-shown, carried at the upper end of the sleeve 9 and rotated thereby. Preferably, until a predetermined speed is attained, the plate 21 is positively driven by engagement of plate 5 with lug 7, and thereafter the governor acts and advances plate 21, until at' suitably high speed advance of plate 21 and cam 10 is limited by engagement of lug 7 with the other end of aperture 30.

With increasing speed the weights 23 r0;

tate on their pivots 22, the centrifugal force causing theweights 23 to move outwardly in opposition to the tension exerted thereon by the spring or springs 28. Such pivotal movement of the arms 23 upon their pivots 22 causes rotation of the plate 21 with respect to the plate 5, and such rotation of the plate 21 effects a rotation of the cam 10 with respect to the shaft 3, thereby advancing the ignition as the speed is increasing, and retarding the ignition as the speed decreases.

In a general or broad sense, the operation above described is that heretofore known in the art. I have found, however, that by reversing the relation of the governor plates, as 5 and 21, as herein described, that is, by attaching the main governor plate carrying the weights to thecam or its equivalent, thereby producing a movable cam system or unit of considerably greater weight and inertia, and by applying the other governor plate, as 5-, to the driving or timer shaft, as 3, the advance of the cam ahead of the shaft 3 with increasing speed is regular and smooth, for example, as indicated by the characteristic curve A, Fig. 9, wherein abscissae are speeds of the engine crank shaft and ordinates are degrees of advance of the cam 'with respect to the engine crank shaft. The curve A is to be contrasted with curve B, which indicates a mode of behavior where the plates 5 and 21 are reversed, that is,

i C, on curve B, it will be noted that with increasing speed the cam is advanced, but that upon reaching a certain speed range the cam is actually retarded throughout a small speed range and thereafter is again advanced with increasing speed. The behavior as indicated at C is irregular or erratic, and is undesirable, and I have found that by reversing the relation of the governor plates 5 and 21 and employing them as herein described, the defects of performance indicated by curve B are overcome and the smooth and regular performance indicated by curve A is procured.

As a matter of belief merely, and without prejudice, it appears that when the plate 5" is attached to the cam and the weight-carrying plate 21 is secured to the timer shaft, as 3, the cam system or unit has so small inertia or mass that the spring 14 of the light movable interrupter structure comprising the arm 15 is able, at a certain speed or within a certain speed range, artificially to advance the cam system independently of;

the action or control of the governor by forc ing the cam shoe 16 against the am immediately after a high point, as 10 on the cam has passed the shoe 16, such pressure of the shoe 16 u on the cam then forcing the cam system a ead or advancing it, this being possible because of lost motion, however slight, between the parts of the governor structure. Or, differently stated or viewed, the pressure of the cam shoe 16 upon the cam 10 produces a drag or braking effect upon the cam system or unit, and due to irregularities, unevenness or variations in such drag or braking effect, there occurs crratio or irregular behavior, such as indicated at C on curve B. By imparting to the cam system or unit sufficient mass, it ossesses sufiicient inertia against or success ully resists the effects of such irregular or variable braking or drag so that regular performance such as indicated by curve A as procured. For brevity, this inertia is referred to as angular inertia, in the sense that the inertia opposes sudden motion of rotation or angular adjustment of the cam unit or system.

The herein described governor is characterized by very small weight or mass, parti'cularly as to the plate or member 21 and the thereto pivoted or attached weights 23. It is in the use of such a light weightrgovernor structure that the attachment of the weight-carrying governor plate to the cam and distributor system is of significance in procuring the smooth and regular angular adjustment in response to speed changes. This governor plate and its attached weights together with the cam and distributor system have a combined weight, mass or inertia of which the weight, mass or inertia of the cam and distributor s stem is so great a proportion that the a oresaid smooth and ever, as to their application to cam and timing shaft, as herein disclosed, the advance of the'cam is perfectly controlled, presumably because of the'greater mass or inertia of the system, comprising the cam, distributor, the main governor plate and the governor weights.

What I claim is:

1. Ignition timing apparatus comprising an engine driven shaft, a s stem coaxial with said shaft, angularly a justable with respect thereto and comprising an ignitiontiming cam and a distributor, a governor plate of small mass secured to said system, centrifugally operated weights of small mass mounted solely upon said governor plate, a second governor member secured to said shaft, and resilient means opposing movement of said weights in their action in rotating said system with respect to said shaft, said system, governor plate and weights having a mass of which the mass of said system is so large a proportion that the "angular adjustment of said system with respect to said shaft is regular, throughout the range of adjustment, with change 0 speed of said shaft.

2. Ignition timing apparatus comprising i nor plate, a second sheet metal governor plate secured to said shaft, said governor plates disposed closely adjacent each other,

and resilient means opposing movement of said weights in their action in rotating said system with respect to said shaft, said s stem, first named governor plate and weig ts having a mass of which the mass of said system is so large a proportion that the angular adjustment of said system with re-' spect to said shaft is regular, throughout the range of ad'ustment, with change of speed of said sha t.

- 3. Ignition timing apparatus comprising i an engine driven shaft, an axially short governor of light weight, a system coaxial with said shaft, angularly adjustable with respect thereto and comprising an ignition-timing cam and a distributor, said governor comprising two sheet metal plates secured respectively to said shaft and to said system, weight structure of small mass pivoted to that governor plate which is secured to said system, the entire weight structure of the governor carried solely by said last named governor plate, resilient means opposing movement of said weight structure in adjusting said system angularly with respect.

to said shaft, said system, last named g0v'- ernor plate and weightstructure having a.

mass of which the mass of said system is so 'ment of said system with respect to said.

shaft is. regular, throughout the range of'10 adjustment, with change of speed of said shaft. A

"In testimony whereof I have hereunto affixed my signature this 23rd day of June,

' ARTHUR ATWATER KENT.

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