US2542085A

US2542085A - Electrical timer

Info

Publication number: US2542085A
Application number: US72118A
Authority: US
Inventors: Waldo J Kelleigh
Original assignee: Gen Control Company
Current assignee: General Controls Co
Priority date: 1949-01-22
Filing date: 1949-01-22
Publication date: 1951-02-20
Anticipated expiration: 1968-02-20

Description

Feb. 20, 1951 w. J. KELLEIGH 2,542,035

ELECTRICAL TIMER Filed Jan. 22, 1949 s Sheets-Sheet 1 M W ld flrl i a Feb. 20, 1951 w. J, KEL H 2,542,085

ELECTRICAL TIMER Filed Jan. 22, 1949 3 Sheets-Sheet 2 Jay PM! Feb. 20, 1951 ELECTRICAL TIMER Waldo J. Kelleigh, Wayland, Mass., assignor to General Control Company, Boston, Mass., a corporation of Massachusetts Application January 22, 1949, Serial No. 72,118

22 Claims. (01. 175-320) This invention relates to switches for controlling an electrical circuit and more particularly to switches of the timer type for modifying a controlled circuit after the elapse of a predetermined time interval. I

Objects of this invention are to provide an electrical timer which modifies a controlled circuit after an elapse of a predetermined time interval, which is accurate and dependable, which is simple and rugged, which is easily adjustable to obtain any desired timing interval, which can be reset during any portion of the timing cycle, which can be mounted on the surface or flush with a supporting panel, which is simple to connect, which can be readily adapted for use with a variety of circuits, which is attractive in appearance, and which advances the art of time switch manufacture generally.

' In a broad aspect the invention contemplates a timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time. Such timer comprises an electric motor which is connected between the terminals;

so that the motor-is continuously operated by the power supply, a member-having a time opening switch. with a normally closed contact, and a switch operating member. Means are pro vided formanually shifting theposition of one of the members from a zero index position, the other member being biased to the zero index position by a spring. A solenoid operated clutch selectively engages the motor thereby to move the biased member against the force of the spring to operate the time opening switch after an elapse of time determined by the selected position of the manually shifted member. A holding switch is operated by the clutch solenoid concomitantly with the engagement of the clutch. This holding switch has a normally open contact for completing a holding circuit to connect the clutch solenoid and the normally closed contact of the time opening switch in series between the terminals of the power supply. A load solenoid of a load relay is adapted to be connected in parallel with a portion of the holding circuit. The solenoid operates a plurality of load contacts connected in the distribution circuit whereby the interruption of the holding circuit by the opcning of the normally closed contact of the time opening switch after the elapse of the predetermined time interval operates the load sclenoid to transfer the load contacts.

In another aspect the members are coaxially.

ing switch. The other disc has an operating member, such as a projecting finger, for operating the time opening switch either directly or through a switch operating lever having a lever ratio (for example 2:1), such that the rotation of the disc required to operate the switch, after the projecting finger contactsv the switch actuating member is considerably reduced thereby to minimize the timing error.

In another aspect the invention contemplates a solenoid operated lever which performs four distinct functions. This lever conjointly engages the clutch to drive the spring biased disc, ope'rates the holding switch and withdraws a roller from an aperture in the spring biased disc. When the solenoid is de-energized the lever forces the roller against the disc thereby acting as a brake to retard the return of the disc to its zero index position. As the disc reaches the zero index position, it is positively centered therein by the roller again engaging the aperture. "In a specific aspect the timer comprises a frame having a stepped bracket on each side thereof for mounting a plurality of terminal blocks. each of which has a' plurality of terminals. An electric motor is mounted on the frame and connected between two of the terminals which are adapted to be coupled to the power supply so that the motor shaft is continuously rotated thereby. A time opening switch with a normally open contact connected to a third of said terminals is mounted upon an index disc adjacent a switch operating lever. A timing disc is arranged coaxially with the index disc so that a projecting finger contacts the switch lever when the timing disc is rotated, the lever ratio being such that the rotation of the timing disc requiredto operate the switch is considerably reduced thereby to minimize the timing error. Each of the discs mounts a respective stop contacting member thereupon to cooperate with a respective stop assembly. Each of the stop assemblies includes a rotatable cylindrical body having a cam sector therein and a finger projecting therefrom to contact the respective disc stop contacting member. A pin is positioned to contact one side of the cam sector thereby restraining further movement of the body'when the finger is located to contact the stop contacting member and preventing further counterclockwise rotation of the respective disc beyond the zero index position. The cam sector is shaped to allow movement of the body as the stop contacting member meets the finger upon clockwise rotation of the respective disc so that the finger is moved out of the way by the stop contacting member thereby permitting a full 360 degree rotation of the disc. The index disc is rotated from the zero index position by a friction drive including an operating knob and a grommet, for example of rubber, with an annular groove for engaging the edge of the disc. A scale divided in chronometric units is carried up on the face of the index disc, the zero scale position corresponding to the zero index position of the disc. The setting of the timer is shown by a fiducial indicator having an aperture exposing the portion of the scale correspondin to the time setting selected by the amount the index disc has been manually rotated from the zero index position. The timing disc is biased to the zero index position against the correlated stop finger by means of a spring. A clutch selectively engages the motor thereby moving the timing disc against the force of the spring to operate the time opening switch after an elapse of time determined by the selected position of the index disc. The clutch is engaged by a lever which also operates a holding switch having a normally closed contact connected to a fourth of the terminals and a normally open contact for completing a holding circuit to connect a clutch operating solenoid and a normally closed contact of the time opening switch in series between the power supply terminals, one end of the solenoid being connected to a power supply terminal, the other end being connected to a fifth of the terminals. A roller is also carried by the clutch lever so that it acts as a brake retarding the return of the timing disc when the clutch is disengaged. The roller also engages an aperture in the timing disc thereby to positively center the disc in the zero index position. The roller is withdrawn from the aperture by the movement of the clutch lever, the clutch engaging, the holding switch closing and roller withdrawing operations being performed conjointly. A load solenoid of a load relay has one end linked to a terminal of the power supply and the other end linked with a sixth of said terminals which is adapted to be connected by means of an external circuit with one of the other terminals, such as the terminal of the normally open contact of the holding switch, the terminal of the normally closed contact of the time opening switch or the terminal linked with end of the clutch solenoid so that the load solenoid is in parallel with a portion of the holding circuit. The energization of the load solenoid operates a plurality of load contacts which are connected in the distribution circuit. .The interruption of the holding solenoid circuit'by the opening of the normally closed contact of the time opening switch after the elapse of the predetermined time interval operates the load relay to transfer the load contacts.

These and other objects and aspects will be apparent from the following description of an illustrative specific embodiment of the invention referring to drawings in which:

Figs. 1 and 2 are front and side elevation views respectively of the embodiment;

Fig. 3 is a front elevation view with the front plate removed;

Fig. 4 is an elevation view of the removed front plate;

Fig. 5 is a cross-sectional view on line 5--5 of Fig. 1;

Fig. 6 is an enlarged cross-sectional fragmentary view of one embodiment of the clutch assembly;

Fig. 7 is an enlarged cross-sectional fragmentary embodiment of a second embodiment of the clutch assembly;

Fig. 8 is a wiring diagram of the timer and an external circuit for normally energizing the load solenoid;

Fig; 9 is a wiring diagram of an external circuit for momentarily energizing the load solenoid at the end of the timing cycle;

Fig. 10 is a wiring diagram illustrating a pump motor control circuit which incorporates the timer; and

Fig. 11 is a wiring diagram of a control circuit for a traffic signal using three timers.

The timer comprises an integral frame Il, preferably cast from aluminum, having a substantially square central web I2 with a traverse member I3 extending normally from each of the respective corners thereof. A bracket I4 for supporting the terminal blocks lia, lIib and lGc projects downwardly from the bottom of each of the respective lower transverse members I3. Both the front and rear of the brackets I4 are stepped so that the terminal blocks I6 mounted thereupon by means of the screws I! are in different vertical planes 'thus simplifying the external wiring to the timer.

Mounted on the rear of the center web I2 is a synchronous electric motor III, The motor I8 is supported with its shaft I9 projecting x through a centrically located aperture 2| in the frame web I2 by means of the screws 22 which engage threads tapped into the web. One disc 23 (Fig. 6) of a coupling is fastened to the projecting motor shaft I9 by means of a set screw 24. The shaft I9 extends through the disc 23 into a recess centrically located in the end of a coaxially disposed extension shaft 26. The opposite end of the shaft is supported by a long sleeve bearing 21. The bearing 21 is secured in an aperture in a dial plate 23 which is fastened to the front ends of the respective transverse frame members I3 by the screws 29 (Fig. 2). Four. similar screws 29 fasten a rear plate 30 to the rear ends of the respective transverse members I3.

Two diametrically located pins 3| project axially from the coupling disc 23 to engage re spective apertures in a mating disc 32. The mating disc 32 is integrally connected by an ana serrated outer face 35 for engaging a similar "serrated face 31 of a second circular plate 28.

The plate 38 has a hub 39 which is secured to the extension shaft by a set screw ll.

The

serrated plates

34 and 38 comprise respectively the movable and stationary members of a clutch 35. The plate 34 is moved axially by the screws 42 (Fig. 5) which project radially into the groove between the disc 32 and plate 34 from the respective bifurcated ends of a clutch lever 43 whose mode of operation will be described in detail hereinafter.

Fig. 7 shows a second embodiment 35a of the clutch assembly 35 above described. This embodiment is preferably used in long period timers wherein the pitch of the serrations of the

plates

34 and 38 of the clutch 35 introduce an appreciable timing error. Clutch 35a incorporates an annular member of resilient plastic material,

tion member. A mating disc 32a has as an annular groove 33a and ends in a'circular member 840. having a conical bearing surface 35a for engaging the O-ring 31a. The ring 31a is secured in a groove 39a in the hub 39b carried by the extension shaft 25. The circular member 34a is moved axially by the clutch lever 43 f Fig. 3) so that its conical surface 340. frictionally engages the O-ring 31a thereby driving the shaft 25 as described below.

Also fixed to the extension shaft 26 by a set screw 44 is a hub 46 which bears against the end of the bearing 21. The end of the hub 46 adjacent the bearing 21 is reduced in diameter to engage an aperture in the center of a member such as the timing disc 41; the disc being held against the shoulder of the hub by peening over the ends thereof in a number of Places as at 48.

A small tab is cut from the material at the outer circumference of the disc 41 and bent to form an axially projecting operating member such as the finger 49 for contacting one end of a switch operating lever (Fig. 4) carried by a member such as the index disc 52. The finger 49 also acts as a stop contact member as will be described below. The lever 5| has a circular aperture therein through which projects a screw 53 engaging threads tapped in aligned holes in the index disc 52, a stop contacting member or plate 54 whose use will be described below, and a switch actuating face 55. A washer 58 is inserted between the lever 5| and the plate 54 so that the lever moves freely with respect thereto; the screw 53 acting as a fulcrum allowing the lever to contact with face 55 the actuating member of a time opening switch sl which is also carried by the index disc 52. It will be noted that the lever ratio is approximately 2:1 thus reducing the travel required after the disc finger 49 contacts the end of the lever 5| to trip the switch 'sl thereby making the exact point of tripping less critical, a distinct advantage "which increases the accuracy of the timer. To protect the switch s| from overtravel of the disc 41, a screw 51 projects through a slotted aperture 51a in the lever 5| to act as a stop.

The index disc 52 is supported upon a sleeve 58 (Fig. 6) having one end reduced in diameter to engage an aperture in the disc center. The disc 52 is held against the sleeve shoulder by peening in a number of places as at 59. The inner surface of the sleeve 58 rotatably engages the outer surface of the bearing 21 so that the disc 52 can be turned with respect to the bearing 21 as will be described below.

An adjustable stop assembly 6| (Figs. 4 and 5) is mounted at the top of the dial plate 28 by means of the screws 52 to provide a zero indexing point for the

discs

41 and 52. This assembly 6| includes a U-shaped frame 53 having a pivot screw 64 projecting normally from the center of the cross piece thereof. The screw 64 carries two rotatable stops 56 and 61 thereupon which are maintained in spaced relationship by means of the washers B8 and 69. Each stop has a finger 1| extending from a rotatable cylindrical body 12 with an aperture therein for the pivot screw 64 and a sector shaped portion 13 cut from the body 12 to provide a cam surface against which bears a pin such as the screw I4 projecting from one side of the stop frame 63. The screw 14 is adjusted to contact the vertical surface of the cam sector 13 when the extended finger H is positioned vertically thereby preventing the disc finger 49 (or stop plate 54) from rotating counterclockwise beyond the zero index position. The

screws 14 are maintained in adjusted position by the respective locknuts 15.

When the disc finger contacts finger 1| from the opposite side upon clockwise rotation of the disc 41; the stop body 12 turns about the pivot screw 54 until the end of the screw 14 contacts the opposite sector surface whereupon the finger 1| prevents further rotation. It is apparent that by proper proportioning of the cam sector 13, the stop body 12 will turn sufliciently to provide a full 360 degree rotation of the disc, further rotation then being prevented by the bearing of the screw against the cam surface. The stop for the index disc 52 is similar in construction and operates in an analogous manner by contacting the stop plate 54 which also acts as a mounting base for the lever 5 I.

The index disc 52 is rotated manually by means of a frictiondrive including a knob 16 located upon the outer end of the shaft 11 which projects through the lower right hand corner of the dial plate 28. Fixed to the opposite end of the shaft 11 is a rubber grommet 18 having an annular groove 19 in its outer surface for engaging the edge of the index disc 52. The timing disc 41 is rotated in a clockwise direction by the engagement of the clutch 35 as will be decribed in detail below. With the clutch disengaged, a restoring force provided by a clock spring 8| maintains the timing disc 41 in the zero index position with the finger 49 against the finger 1| of the rotatable stop 61.

The clutch lever 43 is rotatably supported upon a shaft 82 the ends of which are journaled in the bosses 83 which project from the frame web l2. A cap screw 84 acts as a set screw to prevent relative motion between the lever 43 and the shaft 8|. The screw 84 is made of sufficient length so that the end thereof projects to hold the stationary end of the clock spring 8|. A clutch solenoid 85 (Fig. 5) is mounted on the rear of the web |2 adjacent the motor l8 by the screws 85 to provide, as its first function, a means of operating the clutch lever 43 so that the screws 42 threaded in its bifurcated end move the circular plate 34 to bring the serrated clutch surfaces 35 and 31 into engagement.

The translational force of the solenoid armature 81 is converted into torque by an arm 88 (Fig. 3) which extends through an aperture 89 in the frame web I2. One end of the arm 88 is connected to the solenoid armature 81 by a spring 9| which provides an elastic link between the arm and armature so that the armature is certain to seat thus eliminating chattering and vibration. The other end of the arm 8 engages the threaded end of a collar 92 being secured thereto by prick punching f the exposed threads as at 93. A set screw 94 fastens the collar 92 upon the shaft 82 adjacent the boss 83. A second collar 96 is similarly secured to the shaft 8| adjacent the other boss 83 thereby preventing axial movement of the shaft 82. Restoration torque is provided by a spring 91 connected between an aperture in the arm 85 and an eye in the end of an adjustable screw 93 which engages threads in a boss 99 at the junction of a web |2 and the upper transverse member |3. The screw 98 is locked in adjusted position by'means of a nutlfll.

A second function of the clutch lever-43 is to act as a brake retarding the return of the timing disc 41 to the index or zero position. The portion of the clutch lever 43 extending above the shaft 82 has an arm ||J2 projecting normally therefrom to carry a roller such as the outer race ring I63 of a small ball bearing which is secured to the arm by a screw I64. The spring 61 forces the roller I63 against the side of the timing disc 41, the drag exerted thereby decelerating the return of the disc so that the third function, the positive zeroing" of the disc 41 can be accomplished by the lever 43. When the index disc 62 is in the exact zero index position, the roller I63 drops into a slotted aperture I66 cut in the disc as is shown in Fig. 5. If the disc 62 is not held precisely in the zero index position by the finger H of the rotatable stop 66 as described heretofore, the roller I63 will tend to be partially out of the aperture I66; but because of the force exerted by the spring 61 the roller I63 is forced into the slotted aperture I66 so that the disc 62 is moved to the zero position. It will thus be seen that roller I63 provides a braking member when contacting the side of timing disc 41, and that it provides a zeroing latch when it contacts the zeroing deformation of the disc constituted by aperture I66.

The fourth function of the clutch lever 43 is the operation of a holding switch 32 which is mounted on the front of the web I2 by the screws I61. This operation is accomplished by a cap screw I66 threaded into the underside of the bent end I66 of the clutch lever 43 so that the head thereof contacts the actuating member III of the switch s2. The screw I66 is locked in adjusted position by means of a nut H2.

The timer is provided with a load relay having five load switches SI, S2, S3, S4 and S5 each of which has a normally closed contact II3, a moving contact H4 and a normally open contact 6. As is best shown in Fig. 5, these contacts are supported near the end of respective leaf springs II1 so that the opening (or closing) of the contacts provides some relative sliding or "wipe" to prevent sticking and poor electrical contact. An auxiliary leaf spring H6 is provided adjacent each of the respective stationary contact springs II1 to limit the movement thereof. The contact carrying leaf springs II I are separated by plastic blocks II6, the blocks and' springs comprising each respective switch S being fastened to a switch support bar I2I by means of two screws I22 which thread into the bar. The ends of the support bar I2I are bent at right angles thereto and fastened to the respective terminal block brackets I4 by the screws I23 so that the switches S are positioned in front of the lower portion of the frame web I2. A barrier I24 of plastic or other insulating material is fastened between the switches S and the support bar I2I so that the switches are insulated from the frame web I2.

The load switches S are operated by a load solenoid I26 (Fig. 2), mounted on the back of .the frame web I2 on the opposite side of the motor I6 from the clutch solenoid 66, through a gbent lever I21 extending through an aperture I26 (Fig. 3) in the web I2, One end I26 of the lever I21 is bifurcated to engage a shaft I3I which is journaled in the bosses I32 extending from the 'frame web I2. The opposite end of the lever I21 terminates in a finger I33 which engages a pin I34 in the solenoid armature I36 so that the lever pivots about the shaft I3I when the solenoid I26 is energized. Suflicient restoring torque is ordinarily supplied by the elasticity of the bent portions I46 of the leaf springs I11 of the switches S. If additional torque is required, it may be supplied by a spring I36, one end of which engages an aperture in the lever I21, the other end 8 being secured by a pin Ills which projects from the rear of the web I2. The upward movement of the lever I21 is restrained by an adjustable stop such as the screw I36 engaging a threaded aperture in a boss 66a located at the junction of the web I2 and an upper transverse member I3.-

An actuating bar I31 is maintained in parallel relationship with the shaft "I by two support members I36 located at the respective ends thereof. Each member I36 has an aperture therein through which passes the shaft I3I, relative motion therebetween being prevented by a set screw I36. Also extending from the bar I31 is a bent rotating arm I which projects upwardly to lie adjacent the bent lever I21 near the bifurcated end I26 thereof. The lever I21 and arm I4I are connected by a screw I42 which projects through a slotted aperture I43 in the lever to engage a thread tapped in the arm.

It is apparent from the above that energizing of the solenoid I26 moves the armature I36 downwardly to pivot the bent lever I21 about the shaft I3I as a fulcrum point so that the arm moves the support bar I31 in a path having a locus describing a partial arc of a circle with a center coinciding with the axis of the shaft and a radius equal to the distance between the axis of the shaft I3I and the support bar I31. By means of the slotted aperture I43 the relationship between the lever I21 and the arm I can be made such that the are described by the bar I31 intersects the bent portion I of the respective moving contact leaf springs II1 thereby to conjointly operate the switches S upon energization of the solenoid I26. To electrically isolate the respective switches S from each other, the portion of the bar I31 which would otherwise come in contact with the leaf springs H1 is insulated by a semicircular plastic rod I46 secured to the bar a by means of the screws I41.

A reset switch s3 is also provided in the timer. the normally closed contacts thereof being mounted in front of the end load switch SI by means of the screws 446 which are also used to secure the load switch SI to the support bar III. The switch s3 (Fig. 5) comprises two leaf springs I6I, each having an electrical contact I62 and an adjacent auxiliary leaf spring I63, separated by a plastic block I64. Electrical interconnection between the switches 83 and SI is prevented by positioning a nonconducting barrier I46 therebetween. An aperture I66 (Fig. 3) is provided in the front leaf springs I6I and I63 to provide clearance for an operating finger I66 of nonconducting material which is threaded upon one end of a rod I61 projecting outwardly through the lower left hand corner of the dial plate 26. An operating knob I66 is attached to the other end of the rod I61. The switch s3 is operated by pushing the knob I66 inwardly against the force of a spring I66 compressed between the knob and the face of a front panel I6I, so that the finger I66 projects through the aperture I66 to push the rear leaf spring I6I thereby to open the contacts I62.

The front panel I6I is secured to the dial plate 26 by the screws I66 (Fig. 1). A large circular aperture I62 is cut in the front panel I6I so as to be coaxially located with respect to the extension shaft 26. The aperture I62 is enclosed by a plate of transparent material I63 which is secured between two gaskets I66 by the screws I66.

The end of the extension shaft 26 projecting out through the dial plate 26 is tapped to receive a screw I81 which secures a pointer I88 to the shaft end. A dial I88 is fastened to the dial plate 28 so that it is visible through the transparent plate I83. The dial I88 is divided into chronometric units correlated with the rotational speedof the motor I8 so that the pointer I88 indicates the time interval which has elapsed from the starting of the timing cycle.

A scalebearing member I18 is coaxially attached by means of its inner portion I'Illa to the index disc 58. The outer portion II8b of the member I18 being axially disposed with respect to the inner portion as at II8c so that the front face thereof which has a chronometrically divided scale I88a embossed thereupon is positioned immediately behind an aperture III in the dial plate 28. The scale IBM is correlated with a ilducial indicator, or pointer I88b wherebythe portion of the scale corresponding in time units to the time setting selected by the degrees the disc has been manually rotated from the zero index position by means of the knob I8 is exposed in the aperture I1 I, see Figs. 1 and 7.

The wiring diagram of the timer is shown in Fig. 8. The motor I8 is permanently coupled to the terminals H and t2 which are connected to a power supply (not shown) thereby causing the motor shaft I9 to rotate continuously in a clockwise direction. A holding circuit for energizing the clutch solenoid 88 includes the normally closed contact of the time opening switch sI, the normally open contact of the holding switch s2 and the normally closed contact of the reset switch s3 which contacts are connected in series with the solenoid 88 between-the power supply terminals tI and t2. The normally open contact of the time opening switch III and the normally closed contact of the holding switch s2 are linked with the terminals t3 and t4 respectively. One end of the load relay solenoid I28 is connected with the power supply terminal tI, the other solenoid end being connected to a terminal t8. For convenience when connecting the timer to an external circuit, the terminals tI-t8 are preferably located upon the top terminal block I8a as is shown in Fig. 1.

In Fig. 8 the timer is shown connected to an external circuit linking the terminals t4 and t8 whereby the load solenoid I28 is normally energized. If desired the link between the terminals t4 and t8 may include an interlocking switch Si which is associated with the distribution circuits connected to the switches SI-S as will be described in detail below.

The timer operation is started by momentarily closing a normally open switch or starting push button Ss to conductively connect the terminals t2 and t5 thereby energizing the clutch solenoid 85 from the power supply terminals H and t2 The energization of the solenoid 88 engages the clutch 35 to start the rotation of the timing disc 41 and concomitantly closes the normally open contacts of the holding switch 82 to complete the holding circuit including the switches sI and s3, which shunt the push button Ss. The normally closed contacts of the switch 32 conjointly open to de-energize the load solenoid I28 thereby transferring the load switches SI-S5.

After the elapse of a time interval determined by the manual setting of the index disc 52, the finger 49 on the disc 41 moves the switch operating lever 5I momentarily to transfer both the normally closed and normally open contacts of the time opening switch sI, a characteristic feature which is of importance in certain practlcal applications such as described below with reference to Fig. 11." The interruption of the holding circuit by the switch sI de-energlzes the solenoid thereby releasing the clutch 35 so that the timing disc 41 is returned to the zero index position by the spring 8|. The switch actuating mechanism III is conjointly released by the clutch lever 48 thus closing the normally closed contacts of the holding switch s2'to energize the load solenoid I28 and transfer the load switches SI-S5.

The timer can be reset before the end of the timing cycle by opening the holding circuit of the clutch solenoid 88 by means of the reset switch $2. The switch Si is opened either manually or in response to an electrical or mechan-- ical signal from the apparatus being timed to de-energize the load solenoid I28 and transfer the switches SIS5 without starting the timing cycle. In case of failure of the power supply, an armature element in the field of the motor I8 moves forward to actuate a bell crank I14 which contacts the clutch lever 43 so that the clutch is maintained in engagement and the holding switch 82 remains closed thereby to continue the timing cycle upon the restoration of the power supply, the total length of the cycle being the same as if no interruption had occurred.

In Fig. 9 is shown another external circuit by means of which the load solenoid is energized momentarily at the end of the timing cycle. The terminals t2 and t5 are again connected by a starting push button 83. The terminal t8 is linked to the terminal t3 so that the load solenoid I28 is energized by t e normally open contacts of the time opening switch sI only when the switch is operated at the end of the timin cycle.

In the preferred method of connecting the timer, the leads from the external circuit or circuits are brought to the terminals in the lower terminal blocks I81) and I8c as, for example, the terminals t'2--t8 are used for the circuits shown in Figs. 7 and 8. The connections to the timer are then completed by connecting the correlated terminals by short leads or conducting metal straps such as the jumpers I13. The use of the jumpers I13 greatly facilitates the wiring, and provides a quick convenient means of changing the manner in which the timer is connected to the external circuits. The auxiliary terminal block I8!) and I8c also provide a plurality of junctions for the connections to the load switches SI-S5.

A practical use for the timer is illustrated by the schematic wiring diagram in Fig. 10 of the power and control circuits for a motor M driving a pump (not shown) for emptying a tank. A pump motor M is connected to the terminals a and c of a power source (not shown) by the normally closed contacts sic and sIb of the load switch SI. The timer clutch solenoid 88, the reset switch sit, the normally open contacts of the holding switch 32 and the normally closed contacts of the switch sI are connected in series with the power supply by linking the timer terminals tI and t2 with the supply terminals a and 0 respectively.

One end of the load solenoid I28 is coupled to the power supply terminal a. through the timer terminal tl. The other end of the solenoid I28 is linked by the terminal t8 to a normally open relay contact 35, a normally energized circuit for the solenoid I28 being completed to the power terminal through the normally open contacts .920 and 820 of the load switch S2, the terminal t4 and the normally closed contacts 01' the timer holding switch :2, the time opening switch at and the terminal 2. The normally closed contact s2b is also connected to the terminal t4 thereby completing the solenoid energizing circuit in either position of the load switch S2.

Connected in parallel with the contact :5 is a switch s6 controlled by the level of liquid in the tank (not shown) emptied by the pump motor M, such control being accomplished for example, by a. float and associated mechanism which is arranged to close the switch s6 only when the tank is empty. The relay contact .85 is operated by solenoid L5 which is energized from the power supply terminals a and c through the normally open contacts sic and sic of the load switch SI.

The closing of the contacts sin. and sic also connects the starting switch Ss between the power terminal 0 and the solenoid terminal t5.

The tank pump motor M is started by closing the starting switch Ss either manualLv or automatically by means of a signal from other apparatus used in connection with the tank emptying operation. The closing of switch S8 energized the clutch solenoid 86 from the power supply terminals through the load switch contacts sic and sic thereby starting the timer cycle. The holding switch 82 is operated by the solenoid 85 to complete the holding circuit shunting the starting switch Ss and concomitantly to interrupt the circuit energizing the load solenoid I26. The de-energization of the solenoid I28 completes a circuit through the contacts sla and rib of the load switch Si to connect the pump motor M across the power terminals a and c and concomitantly opens the contacts sla and sib to de-energize the relay solenoid L5. The load switch S2 transfers conjointly to close the contacts s2a and s2b.

Under normal operating conditions the pump empties the tank during the timing cycle of the timer. Upon the interruption of the holding circuit by the timing switch sl the normally closed contact of the holding switch s2 completes a circuit through the load contacts $211 and s2b and the tank switch 36 (closed by the emptying of the tank) to energize the load solenoid I26 thereby to open the contacts sic and sic of the switch SI to stop the pump motor M. The contacts sic and slb concomitantly energize the solenoid L5 to close the contact thereby to shunt the tank switch .96 which opens upon the subsequent filling oi' the tank by any conventional means (not shown). If because of sediment, pump wear or for any other reason the tank is not emptied during the cycle of the timer, the tank switch 86 remains open so that the solenoid I28 is not energized to stop the motor M until the completion of the pumping cycle.

In Fig. 11 four timers Ta, Tb, Tc and Td of the type described above are used to control the sequence of illumination of the lamps of a traflic signal installation. The red, yellow and green lamps on one street are designated RI, Yl and GI, those on the intersecting street R2, Y2 and G2. It being understood that the indicia R, Y and G may represent a plurality of lamps of the same color connected in parallel.

This installation is energized from the terminals a and c of the conventional single phase alternating power supply (not shown). The terminals tl of the respective timers Ta, Tb, To and Td are connected to the power supply terminal a so thatmne end of the respective solenoids 86 and I26 are linked to the terminal a. The terminals t2 of the respective timers Ta, Tb, To and Td are connected to the power supply terminal c thereby linking the movable contacts of the time opening switches sl thereto and connecting the respective motors l8 (eliminated from Fig. 11 to simplify the diagram) to the power supply. The terminals t5 and t8 for the timer Ta are linked by a normally closed external switch sla thereby connecting the solenoids 88a and l26a in parallel. The terminals t5 and t6 of the timers Tb, To and Td are linked in an analogous manner by the switches Slb, Bio and Sid. The switches Sla, Sib, [Sic and Sld are mechanically linked together so that the solenoids I26a, i26b, I260 and I26d can be de-energized conjointly without interrupting the timing sequence of the system.

The timer Ta is initially energized by a momentary contact starting switch Ss which is connected between the power supp y terminal 0 and the timer terminal ii. The closing of the switch 8: energizes the solenoid 86a to close the holding switch 82 and start the timing cycle as described in detail heretofore. Upon the elapse of the predetermined timing period the contacts of the time opening switch si momentarily transfer, interrupting the timer cycle and energizing the timer terminal t3. The terminal t2 of the timer Ta is linked to the terminal t5 of the timer Tb so that the switch si of the timer Ta acts as a starting switch for the timer Tb. By means of a similar connection the interrupting of the timing period of the timer Tb starts the timer Tc. The timer Tc after the elapse of its timing period energizes the timer Td which in turn energizes timer Ta thereby causing the above described sequence of operations to be repeated.

Upon the energization of the solenoid l26a, the load switches Sal, Sa2 of the timer Ta transfers so that the green lamp GI is connected between the power source terminals a and c by a circuit including the normally closed contacts of the load switches Sbl, Sci and Sdl of the timer Tb, Tc and Td respectively and the normally open contact of the switch Sal which is closed by such energization of the solenoid l26a. Simultaneously the normally open contacts of the switch Sb2 energize the red lamp R2 on the cross street by a circuit also including the normally closed contacts of the switches Sb2, S02 and 8:12 of thc timers Tb, To and Td respectively.

At the end of the timing period of the timer Ta the switches Sal and Sa2 return to their normal position, thereby extinguishing the lamp CH. The timer Tb concomitantly energizes as described above so that its switches Sbl and SM transfer. The closing of the normally open contact of the switch Sbl illuminates the yellow lamp Yi by means of a circuit completed between the terminals a and c by the normally closed contact of the switches Sci and Sdl. The concomitant transfer of the switch Sbl causes a circuit to be completed through its normally open contact to maintain the illumination of the lamp R2.

The timer To is energized at the termination of the timing period of the timer Tb thereby to transfer the contacts Sci and S02, the normally closed contacts thereof interrupting the circuits to the lamps Yl and G2 respectively. The normally open contact of the switch Sci connects the lamp RI in series with the normally closed contact of the switch Sdl between the power supply terminals a and c. The normally open contact of the switch Sc2 and the normally closed contact of the switch Sd: concomitantly connect the lamp G2 to the power source terminals a and c.

The fourth step of the sequence is initiated by the transfer of the switches S111 and Sd! of the timer 'Id at the conclusion of the timing period of the timer Tc whereupon the normally open contact thereof connects the lamps RI and Y2 directly between the terminals a and c. These amps remain illuminated during the timing period of the timer Td. At the end of such period the timer Td energizes the timer Ta so that the above described sequence of operation is repeated.

If as described heretofore the switches Sla, Slb, Sic and Sid are open conjointly either mechanically or by a solenoid so that the solenoids lZBa, 126b, I260 and l26d are not energized it will be noted as is shown in Fig. 11 that with all the load switches in their normal positions the red lamps RI and R2 are both illuminated. This feature allows trailic on both streets to be stopped in the case of emergency for example when it is necessary to provide a right of way for an ambulance or a fire engine. After the emergency has passed, the closing of the switches S la, Slb, Slc and S Id continues the cycle as if the emergency had not interrupted the sequence thereof.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

l. A timcr operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between said terminals so that said motor is continuously operatcd by said power supply, a member having a time opening switch with a normally closed contact, a switch operating member, means for manually shifting the position of one of said members from a zero index position, a spring for biasing the other member to the zero index position, a solenoid operated clutch for selectively engaging said motor thereby to move the biased member against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted member, a holding switch operated by the clutch solenoid concomitantly with the engagement of said clutch, said holding switch having a normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply, and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit, and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the interruption of the holding circuit by the opening of the normally closed contact of the timing switch after the elapse of the predetermined time interval operates the load solenoid to transfer the load contacts.

2. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between said terminals so that said motor is continuously operated by said power supply, a member having a time opening switch with a normally closed contact, a switch operating member, means for manually shifting the position of one of said members from a zero index position, a spring for biasing the other member to the zero index position, a solenoid operated clutch for selectively engaging said motor thereby to move the biased member against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted member, a holding switch operated by the clutch solenoid concomitantly with the engagement of said clutch, said holding switch having a normally open contact for connecting said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply, and a load relay having a load solenoid with one end linked to a terminal of the power supply and the other end adapted to be coupled with the normally open contact of the time opening switch and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the deenergization of the clutch solenoid by the opening of the normally closed contact of the timing opening switch after the elapse of the predetermined time interval energizes the load solenoid to transfer the load contacts.

3. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between said terminals so that said motor is continuously operated by said power supply, a member having a time opening switch with a normally closed contact, a switch operating member, means for manually shifting the position of one of said members from a zero index position, a spring for biasing the other member to the zero index position, a solenoid operated clutch for selectively engaging said motor thereby to move the biased member against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted member, a holding switch operated by the clutch solenoid concomitantly with the engagement of said clutch, said holding switch having a normally closed contact and a normally open contact for connecting said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply, and a load relay having a load solenoid with one end linked to a terminal of the power supply and the other end adapted to be coupled with the normally closed contact of the holding switch and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the deenergization of the clutch solenoid by the opening of the normally closed contact of the timing opening switch after the elapse of the predetermined time interval deenergizes the load solenoid to transfer the load contacts.

4. A timer operated from the terminals of a power supply to modify after the elapse of a predetermined time an external circuit having an interlocking switch responsive to a change in a selected operating condition, comprising an electric motor connected between said terminals so that said motor is continuously operated by said power supply, a member having a time opening switch with a normally closed contact, a switch operating member, means for manually shifting the position of one of said members from a zero ind :1 position, a spring for biasing the other member to the zero index position, a solenoid operated clutch for selectively engaging said motor thereby to move the biased member again t the force of the spring to operate said switch after an elapse or time determined by the selected position of the manually shifted member, a hold ing switch operated by the clutch solenoid con; comitantly with the engagement of said clutch, said holding switch having a normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply, and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit by means of the interlocking switch and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the change in the selected operating condition overrides the timed operation of the load relay to transfer the load contacts.

5. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between said terminals so that said motor is continuously operated by said member having a time opening switch with a normally closed contact, a switch operatin member, a friction drive having an operating knob for manually shifting the position of one of said members from a zero ind position, a spring for biasing the other member to the zero index position, a solenoid operated clutch for sel ctively engaging said motor thereby to move the biased member against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted member, a holding switch operated by the clutch solenoid concomitantly with the engagement of said clutch, said holding switch having a normally open contact for completing a holding circuit to connect said solenoid and the normally clo ed contact of the time opening switch in series between the terminals of said power supply, and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the interruption of the holding circuit by the opening of the normally closed contact of the timing opening switch after the elapse of the predetermined time interval operates the load relay to transfer the load contacts.

6. A timer operated from a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising a terminal block having a plurality of terminals; an electric motor connected between two of said terminals adapted to be coupled to the power supply so that said motor is continuously operated thereby; a member having a time opening switch with a normally open contact connected to a third of said terminals and a normally closed contact; a switch operating member; means for manually shifting the position oi one of said members from a zero index position; a spring for biasing the other member to the zero index position; a clutch for selectively engaging said motor thereby to move the biased member against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted member; a solenoid for operating said clutch having one end connected power supply, a

to one of the power supply terminals and the other end connected to a fourth of said ter minals; a holding switch operated by the clutch solenoid concomitantly with the engagement of said clutch, said holding switch having a normally closed contact connected to a fifth of said terminals and a normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply; and a load relay having a load solenoid with one end linked to a terminal of the power supply and the other end linked with a. sixth of said terminals, said sixth terminal being adapted to be coupled externally with one of the other terminals so that the load solenoid is connected in parallel with a portion of the holding circuit, and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the deenergization of the clutch solenoid by the opening or the normally closed contact of the timing opening switch after the elapse of the predetermined time interval operates the load solenoid to transfer the load contacts.

7 A timer operated from the terminals of a power supply to modify a, distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between said terminals so that said motor is continuously operated by said power supply, a disc carrying a time opening switch having a normally closed contact, a disc arranged coaxially with the switch carrying disc and having an operating member for said switch, means for manually shifting the position of one of said discs from a zero index position, a spring for biasing the other disc to the zero index position, a solenoid operated clutch for selectively engaging said motor thereby to move the biased disc against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted disc, a holding switch operated by the clutch solenoid concomitantly with the engagement of said clutch, said holding switch having a normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply, and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by tbeload solenoid whereby the interruption of the holding circuit by the opening of the normally closed contact of the time opening switch operates the load relay to transfer the load contacts.

8. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between said terminals so that said motor is continuously operated by said power supply, an index disc carrying a time opening switch having a normally closed contact, a timing disc arranged coaxially with the index disc and having an operating member for said switch, means for manually shifting the position of index disc from a zero index position, a spring for biasing the timing disc to the zero index position, a solenoid operated clutch for selectively engaging said motor thereby to move the timing disc against the force of the spring to operate 17 said switch aiter an elapse of time determined by the selected position of the'index disc, a holding switch operated by the clutch solenoid concomitantly with the engagement said clutch, said holding switch having a normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact oi,the time opening switch in series between the terminals of said power supply, and a load relay having a load solenoid adapted to be'connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby theintermption oi the holding circuit by the opening of the normally closed contact of the time opening switch operates the load relay to transfer the load contacts.

9. A timer operated from the terminals oi a power supply to modiiy a distribution circuit -to an electrical load after the elapse oi a predetermined time, comprising an electric motor connected between said terminals so, that said motor is continuously operated by said power supply, an index disc carrying a time opening switch having a normally closed contact and a switch operating lever, a timing disc arranged coaxially with the index disc and having a projectingiinger to contact said switch lever when the timing disc is rotated, the lever ratio being such that the rotation of the timing disc required to operate the switch is considerably reducedthereby minimizing the timing error, means for manually shifting the position of index disc irom a zero index position, a spring for biasing the timing disc to the zero index position, a solenoid operated clutch for selectively en a ing said motor thereby to move the timing disc against the force of the spring to operate said switch after an elapse 01' time determined by the selected position of the index disc, a holding switch operated by the clutch solenoid concomitantly with the engagement of said clutch,

" said holding switch having a normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact 01' the time opening switch in'series between the terminals of said power supply, and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by the load. solenoid whereby the interruption of the holding circuit by the opening of the normally closed contact of the time opening switch operates the load relay to transfer the load contacts.

10. A timer operated from the terminals oi a power supply to modify a distribution circuit to an electrical load after the elapse oi a predetermined time, comprising an electric motor connected between said terminals so that said motor is continuously operated by said power supply, a disc carrying a time opening switch having a normally closed contact, a disc arranged coaxially with the switch carrying disc and having an operating member for said switch, a iriction drive having an operating knob and a grommet with an annular groove for engaging the edge of one of said discs, thereby to rotate manually the engaged disc from a zero index position, a spring for biasing the other disc to the zero index position, a solenoid operated clutch for selectively engaging said motor thereby to move the biased disc against the force oi the spring to operate said switch after an elapse oi of said power'supply, and a load relay having a load solenoid adapted 'to be connected in parallel with a portion oi the holding circuit and a plurality oi load contacts connected in the distribution circuit and operated by the load solenoid whereby the interruption oi the. holding circuit by the opening of the normally closed contact of the time opening switch operates the load relay to transfer the load contacts.

11. A timer operated from the terminals oi a power supply to modify a distribution circuit to an electrical load after the elapse oi a predetermined time, comprising an electric motor connected between said terminals so that said motor is continuously operated by said power supply, a disc having a time opening switch with a normally closed contact; a disc arranged coaxially with the switch carrying disc and having an operating member for said switch, means for manually rotating the position of one of said discs from a zero index position, a, scale divided in chronometric units carried by the manually rotated disc, the zero scale position corresponding to the zero index position of the disc, a fiducial indicator having an aperture exposing the portion of the scale corresponding in time units to the time setting selected by the amount the disc has been manually rotated from the zero index position, a spring for biasing the other disc to the zero index position, a solenoid operated clutch for selectively engaging said motor thereby to move the biased disc against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually rotated disc, a holding switch operated by the clutch solenoid conconcomitantly with the engagement of said clutch, said holding switch having a normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact oi the time opening switch in series between the terminals of said power supply, and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the interruption oi the holding circuit by the opening of the normally closed contact of the time opening switch operates the load relay to transfer the load contacts.

12. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between said terminals for continuous operation by said power supply, a disc, a time opening switch mounted on said disc and having a normally open contact and a normally closed contact with flexible conductors leading therefrom, a disc arranged coaxially with the switch carrying disc and having an operating member for said switch, means for rotating the position 01' one of said discs from a zero index position, a dial plate positioned parallel said switch carrying disc in spaced relationship therewith and having a iiducial aperture therein, a scale bearinner portion fastened to axially disposed with respect to said inner portion sothat the scale is immediately behind said dial plate aperture, said outer portion and said switch carrying disc thereby defining a passageway for said flexible switch conductors. said scale being divided in chronometric units and having a zero scale position corresponding to the zero index position of the switch carrying disc whereby the aperture exposes the portion of the scale corresponding in time units to the time setting selected by the amount the disc has been manually rotated from the zero index position. aspring for biasing the other disc to the zero index position, a solenoid operated clutch for selectively enga ing said motor thereby to move the biased disc against the force of the spring to operate said switch after an elapse of time determined by the selected position of the m ually rotated disc. a holding switch operated bfi t he clutch solenoid concomitantly with the engagement of said clutch, said holding switch having .a normally connect said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply. and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated auaos's nected between said terminals open contact for completing a holding circuit to by the load solenoid whereby the interruption of the holding circuit by the opening of the normally closed contact of the time opening switch operates the load relay to transfer the load contacts.

13. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between said terminals so that said motor is continuously operated by said power supply, a disc having a time opening switch with a normally closed contact, a disc arranged coaxially with the switch carrying disc and having an operating member for said switch, a friction drive having an operating knob and a grommet with an annular groove for engaging the edge of one of said discs thereby to rotate manually the engaged disc from a zero index position, a scale divided in chronometric units carried on the face of the manually rotated disc, the aero scale positioncorresponding to the zero index position of the disc,

- a iiducial indicator having an aperture exposing the portion of the scale corresponding in time units to the time setting selected by the degrees the disc has been manually rotated from the zero index position, a spring for biasing the other disc to the zero index position, a solenoid operated clutch for selectively engaging said motor thereby to move the biased dhc against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted disc, a holding switch operated by the clutch'solenoid concomitantly with the engagement of said clutch, said holding switch having a normally open contact for completing a holding circuitrto connect said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply. and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the interruption of the holding circuit by the opening of the normally closed contact of the time opening switch operates the load relay to transfer the load contacts.

i4. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time. comprising an electric motor conso that said motor is continuously operated by said power supply. a disc c rrying a time opening switch having a normally closed contact, a disc arranged coaxiaily with the switch carrying disc and having an operating member for said switch, means for manually shifting the position of one of said discs from a zero index position, a spring for biasing the other disc to the zero index position. a clutch for selectively engaging said motor thereby tomove the biased disc against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted disc, a solenoid'operated lever for throwing said clutch. a holding switch operated by the lever conJolntly with the engagement of said clutch. said holding switch having a'normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply. and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the interruption of the holding circuit by the opening of the normally closed contact of the time opening switch operates the load relay to transfer the load contacts.

15. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between said terminals so that said motor is continuously operated by said power supply. a disc carrying a time opening switch having a normally closed contact, a disc arranged coaxially with the switch carrying disc and having an operating member for said switch, means for manually shifting the position of one of said discs from a zero index position, a spring for biasing the other disc to the zero index position, said spring biased disc having a zero positioning deformation therein, a clutch for selectively engaging said motor thereby to move the biased disc against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted disc, a solenoid operated lever for engaging said clutch, a zeroing latch carried by said lever and engaging the deformation in the spring biased disc thereby to center the disc in the zero index position when the solenoid is deenergized, said latch being withdrawn from the deformation conjointly with the engaging of said clutch, a holding switch operated by thev clutch solenoid concomitantly with the engagement of said clutch, said holding switch having a normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply, and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the inter- I 21 ruption of the holding circuit by the opening of the normally closed contact of the timing opening switch operates the load relay to transfer the load contacts.

16. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load circuit after the elapse of a predetermined time, comprising an electric motor connected between said terminals so that said motor is continuously operated by said power supply, a disc carrying a time opening switch having a normally closed contact, a disc arranged coaxially with the switch carrying disc and having an operating member for said switch, means for manually shifting the position of one of said discs from a zero index position, a spring for biasing the other disc to the zero index position, a clutch for selectively engaging said motor thereby to move the biased disc against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted disc, a solenoid operated lever for engaging said clutch, a brake extension carried by said lever to engage the side of the spring biased disc thereby to retard the return of the disc to the zero index positio when the solenoid is deenergized, said extension being withdrawn from the side of the disc conjointly with the engaging of said clutch, a holding switch operated by the clutch solenoid con- 1 comitantly with the engagement of said clutch, said holding switch having a normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply, and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the inter ruption of the holding circuit by the opening of the normally closed contact of the timing opening switch operates the load relay to transfer the load contacts.

17. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between said terminals for continuous operation by said power supply, a disc carrying a time opening switch having a normally closed contact, a disc arranged coaxially with the switch carrying disc and having an operating member for said switch, means for shifting the position of one of said discs from a zero index position, a spring for biasing the other disc to the zero index position, said spring biased disc having a zero positioning deformation therein, a clutch for selectively engaging said motor thereby to move the biased disc against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted disc, alever for operating said clutch, a holding switch operated by the lever, a zeroing and braking latch extension carried by said lever to engage the side of the spring biased disc thereby to retard the return of the disc to the zero index position when the clutch is disengaged, said extension subsequently engaging the deformation in the spring biased disc thereby to center the disc in the zero index position, said extension being withdrawn from the deformation by the movement of the lever to engage the clutch, a solenoid for moving the lever, the

minals of said power supply, and a load relay having a load solenoid adapted to be connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the interruption of the holding circuit by the opening of the normally closed contact of the time opening switch operates the u load relay to transfer the load contacts.

18. A timer operated from a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising a frame having a stepped bracket on each side thereof; a plurality of terminal blocks mounted on said steps, each of said blocks having a plurality of terminals; an electric motor mounted on said frame and connected between two of said terminals adapted to be connected to the power supply so that said motor is continuously operated thereby; a disc having a time opening switch with a normally open contact connected to a third of said terminals and a normally closed contact; a disc arranged coaxially with the switch disc and having an operating member for said switch; means for manually shifting the position of one of said discs from a zero index position; a, spring for biasing the other disc to the zero index position; a clutch for selectively engaging said motor thereby to move the biased disc against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted disc; a solenoid for operating said clutch having one end connected to one of said power supply terminals and the other end connected to a fourth of said terminals; a. holding switch operated by the clutch solenoid concomitantly with the engagement of said clutch, said holding switch having a normally closed contact connected to a fifth of said terminals and a normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply; and a load relay having a load solenoid with one end linked to a terminal of the power supply and the other end linked with a sixth of said terminals, said sixth terminal being adapted to be coupled externally with one of the other terminals so that the load solenoid is connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid, the remaining terminals being open so that they can be used as junctions for the distribution circuit connections when the timer is installed.

19. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between terminals of said power supply and having a shaft continuously rotated thereby, a disc carrying a time opening switch having a normally closed contact, a disc arranged coaxially with the switch carrying disc and having an operating member for said switch, a stop to prevent each of the respective discs from being rotated beyond a zero index position in a direction counter to the direction of rotation of said motor shaft. means for manually shifting the position of one of said discs from the zero index position, a spring for biasing the other disc to the zero index position against the correlated stop, a solenoid operated clutch for selectively engaging said motor shaft thereby to move the biased disc against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted disc, a

holding switch operated by the clutch solenoid concomitantly with the engagement clutch, said holding switch having a normally open contact for completing a holding circuit to connect said solenoid and the normally closed contact of the time opening switch in series between the terminals of said power supply, and a load relay having a load solenoid adapted to be of said connected in parallel with a portion of the holding circuit and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the interruption of the holding circuit by the opening of the normally contact of the time opening switch operates the load relay to transfer the load contacts.

20. A timer operated from the terminals of a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time, comprising an electric motor connected between terminals of said power supply and having a shaft continuously rotated in a clockwise direction thereby, a disc carrying a time opening switch having a normally closed contact, a disc arranged coaxially with the switch carrying disc and having an operating member for said switch, a stop contacting member mounted on each of said respective discs, a stop assembly cooperating with each of the respective stop contacting members. each of said stop assemblies including a rotatable cylindrical body having a cam sector therein and a finger projecting therefrom to contact the respective disc stop contacting member and a pin positioned to contact one side of the cam sector thus restraining further movement of the body when the finger is positioned to contact the stop contacting member thereby to prevent further counterclockwise rotation of the respective disc beyond the zero index position, the cam sector being shaped to allow movement of the body as the stop contacting member meets the finger upon clockwise rotation of the disc so that the finger is moved by the stop contacting member thereby permitting a full 360 degree rotation 01' said disc, means for manually shiftin the position of one of said discs from a zero index position, a spring for biasing the. other disc to the zero index position against the correlated stop finger, a solenoid operated clutch for selectively engaging said motor thereby to move the biased disc against the force of the spring to operate said switch after an elapse of time determined by the selected osition of the manually ruption of the holding circuit by the opening of the normally closed contact of the time opening switch operates the load relay to transfer the load contents.

21. A timer operated from a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time. comprising a terminal block having a plurality of terminals; an electric motor connected between two of said terminals adapted to be coupled to the power supply and having a shaft continuously rotated thereby; a disc having a time opening switch with a normally open contact. connected to a third of said terminals and a normally closed contact; a disc arranged coaxially with the switch disc and having an operating member'for said switch; a stop to prevent each of the respective discs from being rotated beyond a zero index position in a direction counter to the direction of rotation of said motor shaft; a friction drive having an operating knob for manually shifting the position of one of said members from the zero index position; a spring for biasing the other disc to the zero index position against the correlated stop; a clutch for selectively engaging the motor shaft thereby to move the biased disc against the force of the spring to operate said switch after an elapse of time determined by the selected position of the manually shifted disc; a solenoid for operating said clutch having one end connected to one of the power supply terminals and the other end connected to a fourth of said terminals; a holding switch operated by the clutch solenoid concomitantly with the engagement of said clutch, said holding switch having a normally closed contact connected to a fifth of said terminals and a one of the other terminals so that the load solenoid is connected in parallel with a portion of the holding circuit, and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the interruption of the holding circuit by the opening of the normally closed contact of the time opening switch after the elapse of the predetermined time interval operates the load relay to transfer theload contacts.

22. A timer operated from a power supply to modify a distribution circuit to an electrical load after the elapse of a predetermined time. comprising a frame having a stepped bracket on each side thereof; a' plurality of terminal blocks mounted on said steps, each of said blocks having a plurality of terminals; an electric motor mounted on said frame and connected between two terminals adapted to be coupled to the power supply and having a shaft continuously rotated operating with each of the respective stop contacting members, each of said stop assemblies including a rotatable cylindrical body having a cam sector therein and a finger projecting therefrom to contact the respective disc stop contacting member and a pin positioned to contact one side of the cam sector restraining iurthermovement of the body when the finger is positioned to contact the stop contacting member thereby to prevent further counterclockwise rotation of the respective disc beyond the zero index position, the cam sector being shaped to allow movement of the body as the stop contacting member meets the finger upon clockwise rotation of the disc so that the finger is moved by the stop contacting member thereby permitting a full 360 degree rotation of said disc; a friction drive having an operating knob and a grommet with an annular groove for engaging the edge of the index disc to rotate the disc from the zero index position; a scale divided in chronometric units carried on the face of the manually shifted disc, the zero scale position corresponding to the zero index position of the disc; 9. fiducial indicator having an aperture exposing the portion of the scale corresponding in time units to the time setting selected by the degrees the disc has been manually rotated from the zero index position; a spring for biasing the timing disc to the zero index position against the correlated stop finger, said timing disc having an aperture therein for positively determining the zero position thereof; a clutch for selectively engaging the motor shaft thereby to move the timing disc against the force of the spring to operate said switch after an elapse of time determined by the selected posi tion of the index disc; a clutch solenoid having one end connected to one of the power supply terminals, the other end being connected to a fourth of said terminals; a lever for operating by said solenoid to engage said clutch; a holding switch operated by the lever, said holding switch having a normally closed contact connected to a fifth of said terminals and a normally open 26 contact for completing a holding circuit to connect said solenoid and the normally closed contact-of the time opening switch in series between the power supply terminals; a roller-carried by said lever to engage the side of the timing disc thereby to retard the return of the disc to the zero position when-the clutch is disengaged whichroller subsequentlyen'gages the aperture inthe timing disc :thereby to' center the'disc in the zero index position, said roller. being withdrawn from the aperture "by the movement of the lever to engage the clutch, the clutch engaging the holding switch and roller withdrawing operations being performed conjointly; and a load relay having a load solenoid with one end linked to a terminal of the power supply and the other end linked with a sixth of said terminals, said sixth terminal being adapted to be connected externally with one of the other terminals so that the load solenoid is connected in parallel with a portion of the holding circuit, and a plurality of load contacts connected in the distribution circuit and operated by the load solenoid whereby the interruption of the holding solenoid circuit by the opening of the normally closed contact of the time opening switch after the elapse of the predetermined time interval operates the load relay to transfer the load contacts.

WALDO J. KELLEIGH.

REFERENCES The following references are of record in the tile of this patent:

UNITED STATES PATENTS Date