US2897309A - Speed-responsive switch mechanism - Google Patents

Description

July 28, 1959 G. T. RANDOL 2,897,309

SPEED-RESPONSIVEZ SWITCH MECHANISM Filed March 6, 1957 .A 2 Sheets-Sheet 1 3/- g 97 1 53 l6: P 2% 7 7 2 Q 92 26 rl" 24 6Q July 28, 1959 G. T. RANDOL 2,397,309

SPEED-RESPONSIVE SWITCH MECHANISM Filed March 6-, 1957 2 Sheets-Sheet 2 United States Patent SPEED-RESPONSIVE SWITCH MECHANISM Glenn T. Randol, Mountain 'LakePark, Md.

Application March 6, 1957, Serial No. 644,277

11 Claims. (Cl. 200-80) The present invention relates to a new and novel speedresponsive switch device actuated by centrifugal force generated'by a rotatable element movable relatively toward and away from its axis of rotation as a function of its speed of rotation, said device being designed forcontrolling an associated electrical circuit at difierent points within a predetermined operating range thereof and constitutes an improvement in switch mechanism of the type first disclosed in Patent No. 2,716,678 issued to me August 30, 1955.

In a broader sense, my invention concerns a novel speed-sensitive switch mechanism for selectivelycontrol- 1mg; an electrical circuittadapted to control theoperation of an energizable apparatus such as, for example, an electric motor, solenoid and the like, said power devices being situated approximately or remotely to said mechanism, and wherein such apparatus may be energized or deenergized at a plurality of selective stations defining the full operating stroke of an element reciprocably actuated responsive to variations ,in the speed of said rotatable element whereby, for example, said ,actuatable element is operable to cause energization of the apparatus at all stations during speed increase and to cause de-energiza-i tion thereof substantially at all such stations in response, to decrease in the speed of the centrifugally-operated parts and vice versa. Therefore, the present invention contemplates the control of energizable power apparatus through the full operating range of the speed-sensitive control switch whereby minute change in the speediof the rotating element at all points along theoperating range thereof is effective to open and closerthe control circuit responsive to increase anddecrease of speed respectively at a selected point, with continuous increase or decrease in speed being effective to maintain the control switch in its initiallyselected operating position until vthe. opposte direction of actuation occurs.

, More specifically, my inventionvis directed to thetprovision of novel switch mechanism operable in response to minute reciprocable movements ofan element to two operating positions alongthe full operating stroke 'thereof defined by a governor, preferably of the centrifugaltype, operable through a predetermined speed range, said switch mechanism and governorforming a unitary assembly.

The primary objects of the invention therefore, are the provision of a compact and simple speed-sensitive switch mechanism responsive to minute reciprocable movements of an actuatable element, for selectively controlling an electrical circuit at any point along the full operating stroke of said element; the provision of means for operating said mechanism at speeds proportional to the speed ofa rotating element; the provision of means incorporated in said mechanism for accommodating incremental movements of the actuatable element without affecting the then existent relative disposition of the circuit controlling elements; and the provision of means for stabilizing the switch mechanism in its different operating positions despite relative movement of the centrifugally-operated partsin the same direction following establishment of a given operatingposition.

A further and important object of the invention related to the series ofprimary objects immediatelypreceding, is the provision ofwmeans toaccommodate a full operating stroke of the centrifugally-operated means relative to either of said operating positions which in the present disclosure, by way of example, correspond to closed and open positions of .an included movable contact assembly, and wherein said movable contact assembly is operatable to said closed and open positions with respect to apair of fixed contacts substantially at all points along the full stroke of the centrifugal means responsivetto minute reciprocable movements thereof within the operating stroke aforesaid .to thus .produce, in effect, a follow-up control of the energization and de-energization of a power device controlled bythe associated electrical circuit.

Another object relative to that immediately above, is the provision of novel means to enable continued movement of the centrifugally urged parts in the same direc tion after the movable contact assembly has been withdrawn fromthe pair of fixed contacts to open the switch mechanism, without affecting the then existent open disposition ofthe assembly; to enable continued movement of the centrifugally urged parts in the opposite direction after the movable contact assembly has been moved to bridge the fixed pair of contacts and thus close the switch mechanism; and to enable arrested disposition of the centrifugally urged parts during the full operating stroke thereofin either direction without affecting the then obtaining disposition of said contact assembly.

.In the more comprehensive and detailed description to follow, features and advantages not specifically recited hereinbefore will be apparent or noted, reference being had also to the accompanying drawings in which:

Figure 1 is a plan view of a speed-sensitive switch mechanism constructed in accordance with the principles of the present invention;

Figure 2 is a longitudinal sectional view on an enlarged scale taken along the plane IIII of Figure 1, illustrating the control elements of the mechanism inan operated (closed) condition, and the gear-drive for imparting rotational movements to the control elements thereof;

Figure 3 is a fragmentary sectional view similar to Figure 2, illustrating the control elements in a different operated (open) position;

Figure 4 is a transverse sectional view taken along the plane IVIV of Figure 3, illustrating the centrifugally-operated elements on an enlarged scale for clarity of detail; a

Figure 5 is atransverse sectional view taken along the plane V-V of Figure 3 illustrating the switch mechanism on an enlarged scale .for clarity of detail;

:Figure 6 isafragmentary sectional view similar to Figure 3 illustrating the switch mechanism components on an enlarged scale for clarity of detail;

Figure 7 is a transverse sectional view taken along the line VIIVII of-Figure 6 illustrating the yieldable detent drive or ratcheting mechanism operably incorporated between the centrifugally influenced switch actuator and movable contact assembly; and

Figure 8 illutrates a modifiedform of the invention incorporating an expansible friction element in lieu of the ratcheting mechanism.

Like characters of reference designate like parts in the several views with corresponding parts in the Figure 8 modification distinguished, however, by the addition of the letter a, to each numeral and the exponent 1-to eachle'tter. a

The speed-responsive switch mechanism comprising the present invention is designated in its entirety by Ietters GS, and its incorporation in an electrical circuit, generally designated EC, has been resorted to for illustrating and explaining, by way of example, the novel construction and operation thereof.

Referring to the drawing in detail and first to Figures 1-7 inclusive, wherein my new and improved speedresponsive switch is shown as being employed to control the opening and closing of a switch device generally designated SD in a single electrical circuit. The governor device is generally indicated GD and the switch to be controlled thereby is particularly constructed and arranged for actuation from one operative (closed) position to another operative (open) position in response to speed, or other actuating force, variations.

The governor device GD is of substantially conventional construction commonly known as the fly-ball type, and therefore, only such features of construction will be described as will insure a complete understanding of the new and novel switch mechanism SD and its novel utilization of the centrifugal action of the governor for its operation. The governor GD includes a hollow casing provided with an upper, generally cylindrical cuplike casing 11 defining an open-topped inner chamber 12 overlying a lower mounting extension 13 having an exteriorly threaded shank 14 provided with an axial bore 16. The bore at its upper end terminates in a radially enlarged bore 17 defining an open-topped counterbore 18 in continuous communication with the chamber 12. The casing shank portion 14 is threadedly received by a mating threaded aperture 19 formed in a support structure 20, which may conveniently be a bracket member secured to the block of a motor vehicle engine. An output shaft 21, or other source of control speed, carries for rotation therewith a gear or similar toothed member 22, which member 22 meshes with a worm gear or other matingly toothed member 23. The member 23 is pinned as at 24 or otherwise co-rotatably secured to a driven shaft 26 which serves to actuate the control elements of the governor, as will be hereinafter described in greater detail.

The open-topped chamber 12 of the casing is closed by a cap 27 which is circular in configuration and which carries on its upperside a hollow inverted cup-shaped member 28 having an upper end Wall and a peripheral flange 29 normal to the circular side wall thereof and coaxially disposed on said cap. A plurality of registering holes 30, 31, are formed through said flange and cover 27 with the holes in the latter threaded for reception of fasteners 32 such as the illustrated cap screws (Figure 1) to secure the cap 27 and member 28 in a unitary assembly best demonstrated in Figure 1, 2, and 3. The cap or cover 27 is detachably secured to the casing 11 by suitable means, as by cap screws 34 projecting through holes 35 in the peripheral margin of the cover into threaded engagement with threaded holes 36 provided in registering side embossments 37 integral with the exterior of the casing 11.

The member 28 carries on its inner surface a pair of depending generally U-shaped terminals 40, 41 diametrically opposed. The upper confronting inturned legs 42 are secured to terminal posts 43, 44 respectively, the latter projecting through suitable insulative bushings 45 to the exterior of the member 28. The free end portions of the posts projecting above the bushings being threaded for receiving double nuts 46 with a contact bight 47 of each lead wire 48, 49 clamped between said nuts whereby the electric current is conducted to the interior of the switch device SD. The lower inturned ends or legs 50, 51 ,of theterminals 40, 41 are each provided with a contact 52, 53 respectively securely attached to the upper size of each leg 50, 51 and coplanar with respect to each other, said contacts being made of suitable material resistance to heat with minimum arcing. A stem 55 depends from the center of the end wall of the '4 member 28 and is rigidly secured thereto as by a reduced upper end portion 56 projected through a hole 57 and peened over as by riveting. The free end of the stem 55 carried an annular exterior channel 58 adjacent thereto and a split radially expansible friction ring 59 engages said channel. A reduced diameter portion 60 forms the inner terminus of the stem (see Figure 6).

The shaft 26 is journalled for rotation within plain or sleeve-type bearings, one bearing 62 being press-fitted within the bore 16 at the lower extremity thereof and the other bearing 63 being seated in the counter-bore 18 against the shoulder 17 above-described. The shaft 26 carries at its upper end an enlarged circular boss 64 either formed integrally therewith are detachably secured there to for co-rotation, and the boss 64 forms a part of the rotor indicated generally at R. The rotor is generally cylindrical in shape (Figure 4) and is provided with a pair of diametrically opposed upstanding peripheral brackets 66, 67 slotted at 68 to form each with a pair of legs 69, 70 respectively having angularly disposed cross bores 72, 73 with said bores being equipped with press-fitted cross pins 74, 75 respectively for purposes to later appear.

The cross pins 75 pivotally support reversed L-shaped arms 7 6, 77 fitted into slots 68 'with the upwardly projecting free arm 78 thereof terminating in a centrifugal weight or member 80 and the lower arm 81 normal to the free arm is slotted at 82, arms 78 being adapted to engage the cross pins 74 to limit the outward throw of the fiy-weights 80. The circular boss 64 forming the upper end of the shaft 26 has an axial bore 84. Coaxially disposed with respect to bore 84 is a sleeve 85 with its lower end terminating in an external annular flange 86 adapted to have continuous contact with the upper surface of the circular boss, said sleeve being centrally bored at 87 in axial alignment with the axial bore 84. Normally superimposed on the flange 86 is a circular disc member 88 having diametrically opposed ears 89, 90 each slotted at 91 and having a cross pin 92 press-fitted through cross bores 93, said disc having an axial bore 94 terminating at its upper end to form an internal annular shoulder 95 with a counterbore 96 forming the upper terminus thereof, the sleeve 85 being adapted to have a sliding fit within the axial bore 94 with the upper end of the sleeve 85 being in circular alignment with the shoulder 95 in the normal at rest disposition of the governor GD (see Figure 2).

Slots 91 receive the slotted ends 82 of the centrifugal arms 81 in engagement with the cross pins 92 to form a pivotal connection between the centrifugal members 80 and disc 88 whereby said disc is reciprocably movable in response to centrifugal action imparted to the arms 76, 77 by rotational movement of the rotor assembly R. A plunger or riser rod 97 having a normal diameter 98 merging with a reduced diameter portion 99 to form an annular shoulder 10!) substantially intermediate the extremes thereof, is coaxially disposed with respect to shaft 26 with its normal diameter portion slidably engaging the bore 84 and projecting upwardly through the bore 87 in the sleeve 85. A collar member 101 terminating at its lower end into an external annular flange -102 to form a cross section of substantially L-shaped con figuration, is press-fitted onto the reduced diameter portion 99 into engagement with the shoulder 100 whereby the collar 101 and actuator 97 move simultaneously, the flange 102 being disposed for sliding movement within the counterbore 96 and normally engages the shoulder 95 best demonstrated in Figure 2. Accordingly rotational movement of the rotor R is effective to raise and lower the disc 88 responsive to centrifugal force generated by the outward movement of the fly-weights 80, such force being transmitted from the weights through the L- shaped arms 76, 77 pivotally connected to the circular boss 64, thence through the lower arms 81, pivotal connection 82, 92 to the disc 88, it being noted that a the rotational movement of the disc 88 is not imparted to the rod 97 and attached collar 101 due to the lower end of the rod 97 being piloted in the bore 84 and loosely projecting upwardly through the bore 94.

The upper end of the plunger 97 has a diametrically disposed cross bore 104 adjacent the end in which a pair of detents 105 move radially toward and away from each other, said movement being effected and accommodated respectively by an interposed compression spring 106 normally preloaded as portrayed in Figures 6 and 7.

These detents are preferably formed with a cylindrical base merging with conically formed outer ends 107 for an important purpose as will appear.

Telescopically disposed with respect to said upper end of the coaxial rod 97 is a depending tubular member 109 having a longitudinal bore 110 threaded at its upper end 111 (see Figure 6) with the lower end formed with closely generated circular V-shaped parallel ridges 114 forming corresponding V-shaped grooves therebetween, said grooves being engageable by the conical ends 107 of the detents 105, to form a two-way ratcheting connection therebetween whereby the member 109 is axially movable in unison with the plunger 97 a limited distance for a purpose to become apparent. The outer cylindrical surface of the member 109 is formed with a pair of diametrically opposed longitudinal channels 115, 116

adapted to receive inwardly projecting radial tabs 118 struck from the marginal edge 119 of a circular aperture 120 formed in coaxial alignment with the shaft 26 in the cover 27 through which the upper end of the member109 projects into the interior of the cup-shaped member 28, the tabs serving the purpose of preventing rotational movement of the member 109 while accommodating free axial sliding movement thereof. Encircling the tubular member 109 is a normally preloaded helically, formed compression spring 122 with its upper end bearing on the marginal undersurface of the cover 27 adjacent the tabs and the lower end continuously reacting on the collar flange 102 whereby the collar 101 and pivotally connected centrifuges 80 are biased to their respective inward positions shown in Figure 2 wherein the governor GD is substantially at rest. Therefore, when the governor is operating, the centrifugal force resulting is continuously opposed by the action of spring 122 and variations of such force cause in cooperation with the action of said spring 122 the reciprocable movement of the riser rod 97 to elevate and lower the member 109 a corresponding amount defined by a stroke of the member 109 shorter than the predetermined operating stroke of the rod 97, the latter being responsive to the full inward and outward movements of the weights 80 substantially best demonstrated in Figures 2 and 3 respectively.

A circular disc 125 formed of non-conducting material with an upwardly projecting circular boss 126 and a downwardly projecting circular boss 127 terminating in a reduced diameter externally threaded. portion 128, said bosses being coaxially disposed on opposite side of the disc 125 and an annular external shoulder 129 is formed at the point of mcrgence of the threaded portion with the unthreaded smooth portion of the lower boss 127. This disc is equipped on the lower peripheral marginal surface with a ringtype metallic contact element 131 in encircling relationship with respect to the lower boss 127 and is rigidly secured to the disc by fasteners 132 such as the illustrated rivets whereby the circular contact acts as a bridging element between the fixed contacts 52, 53 in normal disposition shown in Figure 2 wherein the disc is disposed between the depending terminals 40, 41 super jacently to the fixed contacts aforesaid. The upper boss is axially bored at 133'for slidably receiving the lower end of the stem 55 and expansible friction ring 59 whereby the frictional engagement between the surface of the bore 133 and'ring 59 serve to stabilize the movable contact disc or member at its two operating positions defined by the circular contact 131 in engagement with the fixed contacts 52, 53 as shown in Figure 2 for the lowermost position, and the uppermost or second operating position being established by the upper end of the boss 126 engaging the undersurface adjacent the stem 55 of the end wall of the cup-like member 28. Accordingly, the stem 55 acts as a pilot for the upper end of the movable contact assembly designated as a whole MC. The closed end of the bore 133 is vented to the atmosphere via a radial port 134 through the wall of the upper boss 126 adjacent the inner side of the closed end thereof.

The threaded portion of the lower boss 127 is engaged with the internally threaded portion 128 to join the sleeve 109 and contact assembly MC as a rigid unit whereby reciprocable movement of the sleeve 109 correspondingly move the movable contact assembly MC into and out of engagement with the fixed contacts 52, 53 to open and close the associated electrical circuit EC as is understood.

In Figure 8 a modified form of the invention is presented by substituting for the detent 105 connection, an expansible split friction ring carried in an external annular channel 141 formed in the upper end of the actuator 97a in substantially the same position as formerly occupied by the spring action detents 105 and cross bore 104 of Figures l-7 inclusive in which they operate. In this modification the closely generated V-shaped grooves 112 are eliminated from the bore of the tubular member 109a to present a smooth working surface 143 for the ring 140 to continuously engage whereby the frictional coefiicient obtaining therebetween is of such magnitude as to effect like movements of the tubular member and riser 97a as defined by the limits of reciprocable movement of the movable contact assembly MC described above. Accordingly, operation of the gover nor GD actuates the weights 80a to raise and lower the plunger 97a in accordance with the centrifugal force generated by said weights above that necessary to counterbalance the reaction of spring 122a, and in so doing the movable contact assembly MC is operated out of and in to engagement with the fixed contacts 52a, 53a to open and close the switch device SD as should be clearly understood.

The primary function of the detent connection of Figures 1-7 inclusive or the modified friction ring connection of Figure 8, between the riser 97 and movable contact assembly MC is to impart minute reciprocable movements to the contact assembly to operate the switch device, as described above, responsive to variations in the speed of a rotating member, said minute reciprocations of the movable contact assembly being shorter than the full predetermined operating stroke of the riser 97 which enables opening and closing or a two closing position of the switch device SD at selected points along the full predetermined operating stroke of the centrifugally influenced riser 97 whereby, for example, an electric motor may be energized to operate during speed increase of the governor device GD to close the switch contacts 52, 53 and for operational purposes as will appear later, these contacts may be opened substantially at the point of closing aforesaid responsive to slight reduction in the speed of the governor at this point or reduction of speed at a point of governor operation at speeds in ex cess of the increase in speed at which the contacts were closed at the first-mentioned point of operation.

Operation engine, or the tailshaftasthe case may be. Further, let

it be assumed that the electricalcircuit EC forms part of; the control circuit for a .power-controlledfriction clutch or automatic drive which is automatically operated in response .to the flow of electric current through the l ad W r 4 .,When the switch contact elements areclosed, as when ;the rnovable element 131 contacts the upper faces of the fix ed contacts 52, 53 to bridgethe latter, current flow,

for example, through the lead conductor 48 to lead conductor' 49 via the. bridged contacts 52, 53, energizes a motor or other electrically. operated apparatus, thelatter being grounded as is understood to complete the circuit, oreither oftheterminal posts 43, 44 may serve as the ground depending on the type of circuit, series or parallel, -in which the energizable apparatus is connected. As a result of the closing, of the switch contacts, current flow is established through the assumed control circuit. When the contacts are open,.as in Figure, 3, current flow 1s interrupted. Thus, it will be appreciated that the present invention provides means for controlling current flow through the conductors 48, 49, and an assumed control circuit EC associated therewith.

tions shown in Figures 3 and 4, and the movable contact 131, and fixed contacts 52, 53 will be separated. Thus no current fiowthrou-gh the contact assembly MC is possible. The cross pins 72 will serve to limit the outward throw of the weights best demonstrated in Figure 3 and the outward centrifugal force-responsive move- ..ment will serve to additionally compress the spring 122.

, As the rotative speed of the shaft 26 decreases, the

:ratio of the spring compressive force to the outward centrifugal force will increase until such time as these two forces-become substantially counterbalanced. After this ,counterbalancing point is reached, further decrease in "speed produces a differential counteraction between the centrifugalv and spring forces whereby the weights 80 will the moved inwardly until the spring 122 retracts the plunger 97 sufiiciently to bring the movable contact 131 intoengagement with the fixed contacts 5 2, 53 thereby closing the switch device SD as shown in Figure 2. Oh-

yiously, the exact point of contact element closing may -be primarily controlled by the compressive strength of the spring 122 in relation to the weight of the ceni t rifuges 80 at a given rotative speed of the latter. In

this way, governor GD construction is contemplated to :utilizeselectively weighted springs 122 having a working ratefrorn a predetermined installed tension such that closure and opening of the switch device SD may occur at relatively low rotating speeds of the shaft 26 or at higher relative speeds according to the control function desired.

I, Referring now to Figures 2 and 3, it will be observe that the opening of the switch device SD is accomplished by the outward action of the weights 80 and this move ment represents only an increment of the full outward throw of the weights from the position of Figure 2 to the position wherein the outer edges of the L-shaped arms 76, 77 engage the cross pins 72. This incremental movement of the riser 97 in response to centrifugal force effects interruption of engagement between the circular contact 131 and associated fixed contacts 52, 53, such movement being exaggerated in Figure 3 for clarity in illustrating the separation of said switch contacts, and for the same reason the space between the upper end of the switch boss 126 and confronting surface portion on the inner side of the end wall of the member 28 is correspondingly abnormal as shown in Figure 2. In Figure i g this incremental or minute elevation of the switch contact. assembly MC is induced by the action of the centrifugal member 80 through the intermediary of the 8 radially releasable detents inengagement vwith the Vi-shaped grooves 1 14.formed inthe ,Gylindrical surface of the longitudinal bore in the tubular, member 109. The weight of the spring 106 is sufficient and continuously acts on the detents 105 to force their conical ends 107 radially outwardly into engaging relationship with the correspondingly shaped grooves, the latter being closely adjacent in parallel relationship and maintain thejr iser 97 and tubulanmember 109 detachably locked. together for simultaneou s movement in both directionsto the limits of said incremental movement thereof defined by the circular contact 131 engaging the fixed contacts 52,

53 and the upper end of the boss 126 engaging ther und ersurface .of the end wall of switch housing 28. Accordingly, the detent or ratcheting mechanism 105, 106, 1-14 is effective to induce simultaneous movement of the tubular member .109 with the riser 97 to elevate and lower. the movable contact assembly MC to place the switch device SD in open and closed condition respectively. .A special novel feature of the present switch mechanism will now be described with reference to Figure 3. In this figure theswitch contacts 52, 53 have been opened responsive to the incremental outward, throw of thecentrifuges 80 and the upper end of the boss 126 moved into engagement with the undersurface of the end wall ofthe switch housing 28 thereby establishing th e limit of the elevating (opening) movement of theinovable. contact assembly MC. 'However, despite this stopped condition of the movable contact assembly, the increase in speed of the shaft 26 of the governor GD following such switch opening operation has caused the weights 80 to move further outwardly radially andthe spring 122 additionally compressed. This latter opetation is accommodated by the detent mechanism. re-

groove 1 14 spaced upwardly from the groove utilized in establishing the incremental switch opening movement of the switch contact 131. In fact, the'weights 80 may be rotated at such speed as to place their respective L- shaped arms 76, 77 in contact with the stop: pins 72 which establishes the limit of the outward throw of said weights and the relativeupward movement of theriser shaft 97, with respect to the tubular member 109 stationed at the limitof its upward movement. Withthe parts in their respective relative disposition as shown in Figure 3, if the speed of the shaft 26 is decreased, it is obvious that the detent connection between the riser shaft 97 and tubular member 109' will lower them, simultaneously to the position shown. in Figure 2 wherein the circular movable contact 131 is in engagement with the fixed contacts 52, 53 to establish the limit ofthe downwardmovement of the tubular member 109 and connected switch assembly MC and further decrease in the speed of the shaft 26 after said contacts 52, 53 have been bridged, results in the riser shaft 97 moving relatively to the tubular member 109 as shownin Figure 2.responsive to the biasing action of the spring 122 madeelfective to lower the riser shaft97 and weights correspondingly operated to their respective innermost positions through loss of centrifugal force. It is thus seen that the present novel switch mechanism GS provides for rapid intermittent openings and closings of the control circuit ES at any. selected intermediate point of the riser shaft 97 along its full predetermined operating stroke in response -to .minutqreciprocations of said shaft induced by centrifugal-spring forces acting thereon. It should be further manifest that at low. rotating speeds ofshaft 26 or at substantially stalled condition of the. governor destalling.

vice GD, the switch mechanism SD reverts to the Figure 2 disposition, and that subsequent opening and closing of the switch SD may be effected at any selected point along the full operating stroke of the riser shaft 97, responsive to minute reciprocable movements imparted to said shaft in accordance with slight variations in the speed of the drive shaft 26 to establish a higher and a lower speed with respect to a predetermined speed factor.

It should be noted that the expansible friction ring 59 carried by the depending stem 55 continuously acts on the engaged surface of the bore 133 to stabilize the movable contact assembly MC in its two extreme positions whereby the contact assembly requires some degree of actuating force for its movement by the centrifugal weights 80 and spring 122, and after an extreme position has been established for the movable contact assembly MC, this friction ring insures that such will be maintained notwithstanding relative movement of the riser rod 97 may ensue. Stated differently, the stabilization of the movable assembly MC is necessary in its two operating positions so that the governor device GD may operate relatively thereto without disturbing such established operating positions until a change of position is desired by movement of the rod 97 in a direction opposite that causing the then existent operating position.

Reverting now, to exemplary .illustrations of using the present switch device to control shifting of change-speed transmissions and the engaging and disengaging of an automotive power-operated clutch disposed in the drive line of the vehicle between the engine and a changespeed gearbox, this switch mechanism finds special use in the automotive field, particularly in the :control of master and transmission friction clutches of the well known single plate and multiple disc types including servo-controlled clutch bands as in the case of planetary gearing.

Assuming the shaft 26 of the present governor device GD is driven from the transmission tailshaft at speeds proportional thereto. A shift-control valve would be provided for controlling energization of the servos and clutches. One end of this valve would be acted on by the present governor switch through the intermediary of a solenoid while the other end would be influenced by the engine accelerator via an interposed preloaded compression spring opposing governor actuation thereof. With the vehicle standing, the transmission will be assumed to be in low speed operative condition. Pressure on the accelerator will cause the vehicle to be driven forwardly in low gear, and at such predetermined speed of the vehicle and accelerator position, the governor will change the switch mechanism to another operating position wherein a higher speed is established in the transmission. Following this point of speed change to the higher gear, the centrifugal members 80 of the governor GD continue to be under the influence ,of increase in vehicular speed and therefore, move the riser 97 of the governor connected to the centrifugal members, relatively to the movable switch contact MC without disturbing the new operating position of the latter causing the higher speed to be effective. With the engine throttle open as required to negotiate a hill and torque of the engine being insufiicient to maintain speed of the vehicle which drops rapidly even though the throttle is maintained open in an engine accelerating direction. .With such vehicular speed reduction and the throttle open, the present governor switch moves the switch contact to its lower gear position causing the transmission to operate to establish such lower gear ratio and thus enable the engine to drivethe vehicle under the load and road conditions involved without any tendency of the engine It is to be noted that the downshift just de scribed occurred at a higher speed range of the vehicle, than the upshift, and without appreciable loss of vehicular speed from the point where maximum engine torque was being utilized. Accordingly, the present switch mecha- 10 nism finds special use in automatic transmission construction for automotive vehicles and the like by enabling normal upshifting operations to occur within a predetermined speed control range thereof for utilization of maximum engine torque as in ascending a steep grade, but at the point of reduction in vehicular speed where maximum torque is insufficient, a downshift to a lower gear ratio is automatically accomplished responsive substantially to the existent throttle position and such incremental decrease in vehicular speed without requiring reduction in speed to the same factor which rendered said lower speed effective prior to the upshift.

Another example of a practical application of the present invention in the automotive field is for con trolling the engine clutch for starting the vehicle and facilitating change in speed within the associated gearbox will now be described:

In vacuum-power operated friction clutches for automotive vehicles which utilize vacuum to withdraw the clutch when the vehicle approaches a complete stop to prevent stalling of the engine, especially when it is desired to bring the vehicle to a complete stop as at a traffic light, should the control valve for the power device of the clutch be activated by a solenoid whereby when the valve is energized it is open to cause the vacuum-power to withdraw the clutch and when deenergized the valve closes to accommodate closure or engagement of the clutch or by a spring. The solenoid valve usually includes means for slowly venting atmosphere into the power device to produce smooth engagement of the clutch as when starting the vehicle.

Under these conditions, the present novel speedresponsive device or governor, when the vehicle is slowed to a stop, completes the electrical circuit to the solenoid valve to open the same and thereby operate the power device to open the clutch. Upon depressing the accelerator, the car starts since the governor is driven from the engine as by the fan belt which when speeded up causes the governor contacts 52, 53 to open and thus de-energize the solenoid valve with consequent admission of atmosphere into the power cylinder for the clutch. If the operator continues to press the accelerator the clutch will smoothly engage and the car gotten underway, but should he dwell on the accelerator and consequently fail to depress the pedal sufficiently to give the engine sufficient power to move the load, this will cause engine speed to drop and possibly, if the driver fails to further manipulate the accelerator in an engine accelerating direction, it may stall. Here is where my novel governor comes into action. With such slight decrease in engine speed, the governor operates to immediately close its contacts and thus open the clutch possibly only slightly enough to enable the engine to operate without loss of speed at the given throttle position and load. The driver now realizing the situation depresses the accelerator further to speed up the engine with consequent clutch engagement and the car is underway.

The main cause of engine stall where a car is equipped with the friction clutch power-operated, is the failure to give the engine sufiicient throttle, and when the engine starts to stall at low speeds as in starting the vehicle, it can quickly come to a fully stopped condition before the driver senses that he should either further depress .the accelerator, or take his foot off the accelerator, the

latter usually requiring too much time with resultant engine-stall.

Note that the governor of the present invention is able to open the clutch at any point through the full operating range thereof, not just at substantially stalled condition of the vehicle, responsive to the driver slightly releasing the accelerator pedal. In this way he maintains throttle on the engine, which is quite necessary in cold weather drive and starting, and by merely alternating the accelerator position fore and aft, the clutch can be closed and opened automatically, respectively, to simu 11 late a follow-up control action for feathering the clutch members into smooth engagement.

If this governor is used to control the change of gear ratios in a step-gear transmission, the very same conditions obtain. Here with low speed engaged, the shift is made to second speed with the governor having two closed (operating positions) instead of the closed and open operating positions illustrated. Should second speed cause decrease in engine speed to a point of possibly stalling the same due to load and road conditions encountered by the vehicle. This slight incremental decrease in engine speed is instantly transmitted to the governor GD to change the contact closure of the governor for low speed operation with resultant shift to low speed.

In starting the car, the slightest release of the accelerator pedal from any given engine accelerating position prevents engine-stall, full release of the accelerator not being required as in conventional power-operated clutches. Accordingly, the present invention in effect simulates the operation of a centrifugally operated friction clutch, where the governor is associated with a clutch control as explained above. However, a centrifugal clutch has the one disadvantage of opening in opposition to the centrifugal action. Special provisions must be incorporated to enable a shift in the transmission by relief of torque where a centrifugal clutch is involved. The governor of the instant invention provides clutch withdrawal irrespective of engine speed which is translated into car speed according to the effective gear ratios of the transmission.

In addition to the close control of contact closing and opening at selected intermediate points between the extremes of the full operating movement of the governor device GD, electrical arcing across contacts is reduced to a minimum as a result of the stabilizing effect of the expansible ring 59 preventing the movable contact assembly MC from vibratory movements independently of the actuating movement imparted thereto by the action of the governor riser 97.

The releasable connection between the tubular member and riser shaft may comprise the ratcheting connection of Figures 1-7 inclusively or the continuous frictional connection of Figure 8, the latter tending to impart a smoother operating relationship from the riser 97 to the tubular member 109 thereby enabling more sensitive operating characteristics of the governor device GD.

Referring to the terminology used in the foregoing description and in the appended claims, the identifying expressions and/ or terms employed are intended to convey meanings which include the range of reasonable equivalents in the patent sense. For example, the expressions, governor, governor device, speed-responsive switch mechanism, switch device, speed-sensitive switch device, are intended to include any structure utilizing centrifugal members for its operation, whether such members are pivotally mounted on the rotating member, or differently mounted to serve the same purpose. The terms upper, lower, top, bottom, downwardly, upwardly," depending, and other directional words and characters are intended to have only relative connotation for convenience in describing the structure as it appears in the drawings, and are not intended to be interpreted as establishing any particular orientation with respect to related structure or position in which the present disclosure is mounted for operation.

Two particular embodiments of the invention have been illustrated and described. It is to be understood, however, that the invention contemplates any and all modifications, substitutions and/ or arrangements thereof that may fall within the purview of the claims hereunto appended.

Having thus described my invention, I claim:

1. In a speed-responsive switch mechanism having a fixed contact element and a cooperating contact assembly movable relatively to two operating positions with respect to the fixed contact element for controlling the condition of an associated electrical circuit and stop means fixing one operating position of said assembly: a rotatable shaft adapted to be rotated at varying speeds; a rotor rotatable with said shaft; a pair of diametrically opposed centrifugal elements coaxially disposed with respect to said rotor; means for pivotally connecting said centrifugal elements and rotor to accommodate movement of the former toward and away from their axis of rotation as a function of their speed of rotation; means biasing said centrifugal elements toward their axis of rotation; an element op erably connected to said centrifugal elements for reciprocable movement thereby; releasable means interconnecting the reciprocable element and said contact assembly to effect concurrent reciprocable element and contact assembly movement so long as said contact assembly is not at said one operating position and to accommodate movement of said reciprocable element relative to said contact assembly after said contact assembly is at said one operating position, whereby pivotal movement of the centrifugal elements is imparted to the latter to selectively establish it in its two operating positions responsive to minute reciprocations of the reciprocable element at any selected position thereof intermediate the limits defining its full operating stroke for controlling-the condition of said electrical circuit.

2. In a speed-responsive device, a rotary shaft; a controllable member; a rotary element fixed on said shaft, a centrifugal element connected to said rotary element for movement between outer and inner positions in a plane disposed substantially at right angles to the plane of rotation of said shaft; preloaded spring means for biasing said centrifugal element toward its inner position; a movable member connected to the centrifugal element for movement therewith through a predetermined operating stroke; stop means for contacting one of said members to limit the extent of movement of said one member to said stroke; clutch means operably disposed between the movable and controllable members and including friction means binding said members for co-movement throughout said stroke accommodating relative movement of said members after said one member contacts said stop means, whereby minute reciprocations of the movable member at any selected position intermediate the limits of the operating stroke thereof impart a like reciprocating movement to the controllable member; and means for rotating said shaft at varying speeds.

3. In a speed-responsive device: a rotary shaft; a rotary member fixed on said shaft; a centrifugal member pivoted to said rotary member for oscillation between outer and inner positions in a plane disposed substantially at right angles to the plane of rotation of said shaft; normally preloaded spring means for biasing the centrifugal member toward its inner position; a movable member connected to the centrifugal member for conjoint movement therewith through a predetermined operating stroke; a switch device comprising a pair of fixed contacts and a cooperating movable contact assembly 'operable in response to limited operating strokes of said movable member of less extent than said predetermined stroke for controlling an associated electrical circuit; clutch means including a relatively movable element resiliently disposed between the movable member and contact assembly to effect co-movement of said movable member and said contact assembly through the limited operating stroke of said contact assembly and to accommodate movement of the movable member alone through the re maining portions of said predetermined stroke.

4. In a speed-responsive device: a rotary shaft; a rotary member fixed on said shaft; a centrifugal member acted onby said rotary member for movement between twopositions in a plane disposed substantially at right angles to the plane of rotation of said shaft; normally preloaded spring means for biasing the centrifugal member toward one of its positions; a fixed switch contact '13 assembly; a movable switch contact assembly comprising a pair of telescopically-related relatively movable elements, one of said elements being operably connected to e centrifugal member for conjoint movement therewith through a predetermined operating stroke, and the other element cooperating with the fixed contact assembly in response to shorter limited operating strokes than the predetermined stroke for controlling an associated electrical circuit; a resilient clutch interposed between said relatively movable elements securing said elements to one another for said co-jo'int movement and accommodating relative movement therebetween upon movement of said one elementbeyond the shorter strokes of said other element, whereby minute reciprocations substantialiy at any selected position intermediate the extremes of the predetermined operating stroke thereof impart like shorter reciprocating movements to both of said elements in unison causing the other element to engage and disengage with respect to the fixed contact to control said electrical circuit; .and means for rotating said shaft at varying 5. The speed-responsive device according to claim 3 in which the movable element of the clutch means comprises: a spring-loaded .detent carried by the movable member and coop'erable with a series of closely generated substantially V-shaped circular shoulders on the movable contact assembly.

'6. The speed-responsive device according to claim :3 in which the movable element of the clutch means comprises: an expansible split-type ring carried by the movable member for frictionally engaging a co-operating surface on the movable contact assembly.

7. The speed-responsive device according to claim 3 in which the movable contact assembly comprises: -a tubular member; an annular disc provided at one end with a coaxial closed end hollow projection of less diameter of non-conducting material; a circular ring-type contact element secured to the face of said disc adjacent its periphery; an externally threaded element projecting from the opposite end of said disc for threaded connection with internal threads provided at one end of the tubular member to form a unitary assembly therewith; a pair of diametrically opposed external longitudinal slots in the tubular member for reception of fixed pnojections to prevent rotative movement of said contact assembly; a fixed element projecting into the hollow of said projection normally spaced from the closed end of said hollow for predetermining the reciprocating stroke of said contact assembly; and an expansible split-type ring carried in an annular groove on the fixed element for frictionally engaging a co-operating surface of the hollow of said projection to stabilize the movable contact assembly in its different positions.

8. In a speed-responsive switch mechanism comprising an inverted cup-shaped housing, a pair of diametrically disposed centrifuge members pivoted to a rotary member fixed on a drive shaft for oscillation between outer and inner positions in a plane disposed substantially at right angles to the plane of rotation of said rotary member, and normally preloaded spring means for biasing said centrifuge members to their inner positions: a cylindrical rod-type riser element provided with an external annular shoulder at an intermediate point of mergence of a normal diameter portion and a reduced diameter portion extending to the respective ends of the element; a circular spring seat of substantially L-shape cross section press-fitted on the reduced diameter portion of said element into engagement with the shoulder thereof for movement together; a circular disc having diametrically disposed upstanding slotted projections provided with two legs; a cross bore through each of the slotted projections normal to the slot; a cross pin press-fitted through the cross bores of each projections; a pair of L-shaped arms having the ends of their substantially vertical arms rigid with the centrifuge member, and the end of the substantially horizontal having a slotted end projecting into the slots of projections aforesaid into engagement with the cross pins aforesaid whereby a pivotal connection is provided between the centrifuge members and disc; a longitudinal bore extending from one end of the disc to an intermediate point to form an internal shoulder with a counterbo re terminating at the other end of the'rot-ary member, said shoulder engagingthe spring seat; a sleeve member having a cylindrical portion and an outtu-rned annular base flange disposed between the rotary member and disc with the flange continuously engaging the upper face of the rotary member and the cylindrical portion pro jecting into longitudinal bore of the disc aforesaid; an axial bore in the rotary member having its upper end open; a bore through the sleeve member of the same diameter as the axial bore in the rotary member and coaxially disposed with respect to the latter; a spring influenced connection having an element carried by "the upper end of the riser rod and radially -movable outwa-rdly to efiect said connection; atubular member telescopically disposed with respect to the reduced diameter portion of the riser rod; a series of closely generated parallelly disposed circular V-shaped ridges in cross section, formed along the interior of the tubular member adjacent one end for engagement by the spring influenced element whereby reciprocable movement of the riser rod imparts like movements to the tubular member; a pair of diametrically opposed longitudinal channels in the exterior surface of the tubular member; a cover for the open end of the housing; a plurality of cap screws for securing the cover to said housing; a circular aperture through the cover and coaxially disposed with respect to the tubular member projecting therethrough; a pair of diametrically disposed lugs inwardly projecting from the marginal portion of said aperture, said lugs engaging the longitudinal channels aforesaid to prevent rotative movement of the tubular member and accommodate relative sliding movement thereof; an inverted cup-shaped switch housing having an end wall with its open end provided with an annular outturned flange and mounted atop the cover aforesaid; a plurality of cap screws in the switch housing flange for securing said switch housing to the cover in coaxial disposition with respect to the latter; an internally threaded portion in the end of the tubular member projecting through the aperture in the cover; a movable contact assembly comprising a circular switch disc of non-conducting material provided with lower and upper coaxially disposed circular bosses projecting from the opposite faces thereof; external threads on the outer surface of the lower boss for engagement with the internal threads of the tubular member to form a unitary assembly therebetween for movement together; a ring-type cont act carried adjacent the periphery of the switch disc on its underside; means for bonding the contact ring to the switch disc; a longitudinal bore in the upper boss; a depending cylindrical stem secured at its upper end to the underside of the switch housing end wall with its lower end projecting into the longitudinal bore of the boss; an annular external channel provided in the stern adjacent the lower end thereof; an expansible split friction ring engaging said annular channel and continuously engaging the cylindrical surface of the boss bore to act as a stabilizing agency for the movable contact assembly; a pair of diametrically disposed terminals rigid at their upper ends with terminal posts projecting to the exterior through insulative bushing carried in apertures provided in the end wall of the switch housing; a pair of fixed contacts carried by the lower ends of the terminals subjacently to the movable ring contact for engagement by the latter to bridge the fixed contacts thereby closing the switch; a control circuit comprising lead wires connected to the external ends of the terminal posts; stop means for. the movable contact assembly to limit the reciprocable move- 15 ment thereof defined by the engagement of the ring contact with the fixed contacts and the end of the upper boss in engagement with the under surface of the end wall of the switch housing, said reciprocable movement being of incremental proportion in relationship to the full predetermined operating range of movement of the centrifugally influenced riser rod and associated switch parts actuated thereby; and means for driving said rotary shaft and member at varying speeds whereby centrifugal force generated by the centrifuge members induces upward movement of the riser rod to impart like minute movements to the movable switch assembly to unbridge (open) the fixed contacts at any selected position Within the limits of the full operating stroke of said riser rod, the latter being accommodated by release of the spring influenced connection aforesaid after the switch has been initially opened to enable a new opening position to be established at a speed factor above or below the speed at which the initial opening occurred.

9. The speed-responsive switch mechanism according to claim 8 in which the first-mentioned spring means comprise a helically formed compression coil spring.

10. The speed-responsive switch mechanism according to claim 8 in which the spring influenced connection comprises a cross bore through the upper end of the reduced diameter portion of the riser rod; a pair of cylindrical elements disposed in said bore and having tapered outer ends for engaging the V-shaped grooves; and a normally preloaded compression spring operably disposed in said cross bore between said elements for biasing them radially outwardly into engagement with said grooves and accommodating relative radial movement thereof toward each other and with respect to the grooves during relative movement of the riser with respect to the tubular member after an operating position of the switch contacts has been established, in response to increase in speed of the rotary member. i

11. The speed-responsive switch mechanism according to claim 8 in which the spring influenced connection comprises an external annular channel provided in the upper end of the reduced diameter portion of the riser rod; an expansible slip friction ring engaging said channel; and a smooth cylindrical surface defining in the telescopic portion of the interior of the tubular member for continuous frictional engagement with the friction ring aforesaid for alternately moving the movable switch assembly into bridging (closed) and unbridging (open) position with respect to the fixed switchcontacts at selected points within the limits of the full operating stroke of the riser rod with relative movement of the latter being accommodated with respect to the movable switch assembly after initial establishment of a selectingoperating position of the switch mechanism.

References Cited in the file of this patent UNITED STATES PATENTS Feigel Nov. 12, 1940 Hale July 1, 1941 Randol Aug. 30, 1955

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