US2079145A - Centrifugal control for timers - Google Patents

Description

May 4, 1937. J. l.. ARTHUR 2,079,145

CENTRIFUGAL CONTROL FOR TIMERS Filed oct. 7, 1955 2 sheets-sheet 1 INVENTOR Yo/ A; ATTORNEY/f May 4, 1937- .1.l L. ARTHUR 2,079,145

CENTRIFUGAL CONTROL FQR TIMERS Filed OG'C."7, 1935 2 Sheets-Sheet 2 iq-5' 2' BY alfINVENTOR W ATTORNEYJ/ Patented May 4, 1937 UNITED STATES PATENT OFFICE CENTRIFUGAL CONTROL FOR TIMERS Application October 7, 1935, Serial No. 43,892

13 Claims.

This invention relates to ignition timer distributors and has to do with improvements in means for controlling the centrifugal advance range for altering the time of ignition.

One of the objects of the invention is to combine a holddown plate with stop means` for limiting the range of flyweight movement.

Another object of the invention is to provide adjustable stop means' whereby the range of flyweight movement may be altered.

A further object of the invention is to improve centrifugal mechanism for altering the time relation of fuel ignition in response to engine speed.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accom.- panying drawings wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a vertical section through a timer distributor illustrating the improvements herein disclosed.

Fig. 2 is a plan view of the holddown plate and stop means for the improved centrifugal mechanism.

Fig. 3 is a plan view of the centrifugal mechanism with the holddown plate and stop; means assembled in position.

Fig. 4 is a fragmentary view in section substantially as illustrated by the line and arrows 4-4 of Fig. 3.

Fig. 5 is an elevational View of the speed responsive mechanism.

Fig. 6 is a horizontal sectional view through the holddown plate substantially as indicated by the line and arrow 6-6 of Fig. 1 illustrating the flyweights in their in position.

Fig. 7 is a view similar to Fig. 6, but illustrating the flyweights moved to their outer position.

Fig. 8 is a view similar to Fig. 7, but illustrating the holddown plate and stop means moved to a second position whereby the range of fly- Weight movement is altered.

(Cl. ZOO-31) driven by the shaft I4 through the agency of a speed responsive mechanism 30 later to be described. Supported within the housing I0 is a breaker plate 32 having a flange 34 providing an inner race for a series of ball bearings 36 equally spaced about the plate by a spacing band 4.6 operating to maintain the balls 36 in operative engagement within an outer race 42, provided by the housing I0. The breaker plate 32 supports a contact bracket 44 to which is secured the usual fixed contact that cooperates with a movable contact kcarried by breaker lever 46, oscillatable about a pivot 48 through the agency of a rubbing block periodically engaged by the cam 28. The breaker lever 46 is urged into engagement with the cam 28 by means of a spring 50 that operates to electrically connect the movable contact with the addition of the lead 52, to a terminal post 54 insulatingly supported by the housing I0. Means are provided for shifting the breaker plate 32 in response to engine developed suction by means of a displacement unit 56, provided with a link 58 pivoted to the breaker plate 32 by means of the device 60. Inasmuch as the breaker plate 32 with its ball bearing support, and the circuit breaker structure is fully disclosed and claimed in a copending application, further description is not deemed necessary herein.

The centrifugal mechanism 36, hereinbefore referred to, comprises a Weight .base 62 press iitted upon a knurled portion 64 of the driving shaft I4 at a point removed from its reduced end 66. Secured within the weight base 62 and at substantially diametric points, there are a pair of pivot posts 68 upon each of which there is pivoted a flyweight IG that has a. cam engaging arm 'I2 as well as a weight arm 14. The cam engaging arm 12 is designed to have rolling engagement with the cam face 'I6 of a cam bar 18, which cam bar is press fitted or otherwise secured upon a reduced portion 8D of the cam 28 or an extension thereof, substantially as illustrated in Fig. l. The cam 28 has a cylindrical bore 82 providing a bearing for the reduced end portion 66 of the shaft I4. Thus it will be seen that the cam 28 is capable of limited rotation, or oscillating movement, upon the extension oi the shaft I4 through the centrifugal mechanism.

In order to further control the amount of angular rotation of the cam 28 upon the shaft extension 66, the cam bar I8 is provided with a pair of spring posts 84 to which springs 86 are connected and thence hooked over the pivot post 68; the springs 86 operating to maintain the iiyweights and cam bar in compact relation substantially as illustrated in Figs. 3 and 6, wherein the weight arms 74 are held in the inward position close to the extension 80 of the cam. Spacers 8f3 are disposed about the pivot posts B8 and between the weight base 62 and the iiyweights '53, and ribs 90 are provided on the weight base for spacing the weightsslightly above the weight base and for reducing the frictional resistance of their inward and outward travel.

Means are provided for confining the weights in their lateral movement upon the pivot post, and for defining the extent of outward movement. These means include holddown plate which holddown plate is in the form of a shallow cup having a bottom wall |02 with a depending flange or skirt |04. The bottom wall of the cup is provided with an elongated aperture of sufficient dimension that the plate may be passed down over the cam 28, and thence moved sideways se that the skirt |04 will substantially embrace the centrifugal mechanism. A second elongated aperture |08 is also provided, and, along with the aperture |03 provide means such that the plate may be passed down over the end of the pivot posts 53, the spring posts 8d the connecting springs 86, and yet allow for clearance of the spring post 84 when rotative movement occurs between the weight base 62 and the cam bar '|8. Still other apertures as the arc like slots Il@ are provided that pass over the reduced threaded end |2 of studs l 4 secured at diainetric points on the weight base 62, thus providing means for holding the holddown plate iGE in spaced relation to the weight base 62, that the iiyweights may move radially without meeting with obstruction. At appropriate points about the skirts or" the holddown plate, there are deformed portions so positioned that when the holddown plate is assembled With the weight base, the tip ends |22 of the flyweights will engage the deformed portions when the flyweights travel to their outer extreme, as illustrated in Fig. 7. The relation of the deformed portions i and the stud receiving slots ||0, are such that rotation of the holddown plate with respect to the weight base will alter the point of engagement between the deformed portion |20 and the tip of the yweight. Also the relation of the .52S is such that relative angular movement of the plates to one extreme permitted by the slots iid and studs lill there will be one point of engagement that will be nearer the axis of rotation than when the two plates are at the other exfrcrne oi relative angular movement permitted by e and stud. Thus, the radial distance from the axis of the assembly to the point of engagement between the deformed portion and the tip oi the rlyweight is lengthened or shortcned depending on the position of the holddown plate and weight base. When the holddown plate and weight base have been moved to the desire-d relative position they may b-e secured in place by an appropriate nut 24 tightened on the stud llfl.

Fig. 8

is illustrative of the results that may be accomplished relative rotation of the holddown plate and the weight base. Arrow A indicates that the holddown plate has been moved upon 'the weight base the limit provided by the slot |55r and stud H4, the parts taking the position illustrated in the full line position of the iig/weights. When the holddown plate has been moved to the opposite extreme provided by the slot li and stud ||4, all of which is indicated by the arrow B, the relation of the parts will then take the position illustrated in the dotted line showing of the holddown plate and flyweights. While the construction thus far described embodies a deformed portion of the skirt |20 as comprising a iiat, other forms of deformations may be utilized, and a modification of that is illustrated in Fig. 7. In that form, the bottom wall 232 of the holddown plate is apertured at 2| so as to leave a bendable portion 220 of the skirt 204 constituting the deformed portion, the remaining portions of the holddown plate being substantially identical with that hereinbefore described, all of which are indicated with the addition of 190 to the reference characters.

In this modied form, the limits of outward travel of the yweights 'l0 are determined by bending the deformed portion 220 inward substantially as indicated, whereupon the yweight lll is engaged by the tip |22 as shown in full lines, or the deformable portion 220 may be bent outwardly as indicated at 220a thus extending the range of outward movement as indicated by the dashed line position of the yweight 10.

While the embodiment of the present invention as herein disclosed, constitutes a preferred .1, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

l. An ignition timer comprising in combination, a circuit breaker, a cam for operating a circuit breaker, a driving shaft, means drivingly connecting the shaft with the cam comprising, a weight base secured to the shaft, a cam bar secured to the cam, a pair of studs provided by each of the bars and the weight base, flyweights pivotally mounted upon the studs of the weight base and having an arm engaging the cam bar, springs secured to a stud of each pair, and a holddown plate superimposed over the cam bar and flyweights for guiding the outward movement of the iiyweights, and means including a depending flange from the holddown plate limiting the outward movement of the flyweights.

2. An ignition timer comprising in combination, a circuit breaker, a cam for operating a circuit breaker, a driving shaft, speed responsive mechanism drivingly connecting the shaft and cam, said speed responsive mechanism comprising, a weight base, flyweights pivotally secured to the weight base, a cam bar mounted on the circuit breaker cam, and normally urged to enga/ge the iiyweights, a holddown plate substantially enclosing the cam bar and flyweights, and means provided by the holddown plate for limiting the outward movement of the iiyweights.

3. An ignition timer comprising in combination, a circuit breaker, a cam for operating a circuit breaker, a driving shaft, speed responsive mechanism drivingly connecting the shaft and cam, said speed responsive mechanism comprising, a. weight base, ilyweights pivotally secured to the weight base, a cam bar mounted on the circuit breaker cam, and normally urged to engage the flyweights, a shallow cup inverted over the flyweights and cam bar, means supporting the cup from the weight base in spaced relation with the said weights and bar, and means comprising a portion of the side wall of the cup for limiting the outward movement of the flyweights.

4. An ignition timer comprising in combination, a circuit breaker, a cam for operating a clrcuit breaker, a driving shaft, speed responsive mechanism drivingly connecting the shaft and cam, said speed responsive mechanism comprising, a weight base, iiyweights pivotally secured to the weight base, a cam bar mounted on the circuit breaker cam, and normally urged to engage the yweights, a plate member superimposed over but spaced from the cam bar and iiyweights, and depending portions from the plate member disposed for engagement by the free ends of the flyweight thereby limiting the outward movement of the flyweights.

5. The combination set forth in claim 1 wherein the holddown plate is apertured so as to pass over the studs and springs and permit their lateral movement, said holddown plate having provisions for limited rotation with respect to the weight base whereby the limits of outward flyweight movement may be altered.

6. In a timer having a circuit breaker and an engine operated cam for actuating the circuit breaker, the combination of means for altering the angular relation of the cam to the circuit breaker in response to engine speed comprising in combination, a driving shaft, a support provided by the shaft and rotating therewith, ilyweights pivoted upon said support, a cam bar secured to the cam and spring urged to normally engage the flyweights, and holddown means for guiding and limiting the movement of the flyweights, said holddown means comprising, a plate having apertures whereby the plate may be passed over the cam and the spring urging means maintaining the flyweights in centralized position, means for securing the plate to the support in spaced relation with the flyweights, said securing means including arcuate slots in the plate disposed over threaded studs on the support whereby the plate may be moved angularly relative to said support, and depending flat portions provided by the holddown means disposed at the outward limit of flyweight travel whereby the flyweights combination, a driving shaft, a support provided by the shaft and rotating therewith, fiyweights pivoted upon said support, a cam bar secured to the cam and spring urged to normally engage the rlyweights, and holddown means for guiding and limiting the movement of the flyweights, said holddown means comprising, a sheet metal cup disposed over the ilyWeights and whose side walls depend over the support, said side walls providing flats disposed at the point of iiyweight engagement for limiting the outward movement of the flyweight.

8. In an ignition timer, a speed responsive mechanism comprising in combination, a shaft, a weight base mounted intermediate the ends of said shaft and provided with a pair of pivot posts, a cam mounted for oscillatable movement upon one end of the shaft and providing a cam bar, spring posts mounted in each end of the cam bar, Ilyweights mounted on the pivot posts, and springs secured to the spring post and pivot post for maintaining the yweights in compact relation, a holddown plate apertured to fit over the cam, springs, and supporting post and be disposed in close relation to the yweights and cam bar, means spacing the plate from the weight base and providing for limited rotation of the plate with respect to the base, said plate having a depending skirt substantially enclosing the weight base, and deformed portions in the depending skirt for limiting the outward throw of the flyweights.

9. The combination set forth in claim 8 in which the deformed portions of the skirt comprise flats angularly shiftable by the limited rotation of the plate relative to the weight base for altering the range of outward travel of the flyweights.

10. The combination set forth in claim 8 in which the deformed portions of the skirt comprise, bendable sections for varying the limitation of ilyweight travel.

11. The combination set forth in claim 8 in which the plate is apertured opposite the skirt deformations to weaken the skirt support, and wherein the skirt deformations may be bent toward or from the shaft for varying the extent of flyweight travel.

12. In a speed responsive mechanism for an ignition timer, wherein flyweights and a cooperable cam bar operate to effect an angular shift between a pair of coaxial shafts in response to variation in driven speed of one of the shafts, holddown means and weight stops for the yweights, comprising in combination, a plate disposed over the flyweights, skirt portions provided by the plate engageable by the weights at one extreme of their movement, thus limiting the outward travel of the flyweights, and means defining the angular relation of the skirt portion with respect to the flyweights, said defining means being alterable so as to vary the extent of outward travel of the flyweights.

' 13. In centrifugal means for an ignition timer, the combination comprising, a weight plate, flyweights carried by the weight plate, and a holddown plate secured in spaced relation to the weight plate for confining the movement of the flyweights, said holddown plate having skirt portions to be engaged by the ilyweights at one extreme of their movement, and means for shifting the holddown plate relative to the weight plate for altering the extent of travel of the flyweights.

JAMES L. ARTHUR.

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