Title:
AUTOMATIC SEQUENCE CONTROL APPARATUS
United States Patent 3863079


Abstract:
Automatic sequence control apparatus for a sprinkling system having a main electrically activatable valve ahead of a number of individual electrically activatable valves controlling flow to groups of sprinklers. Adjustable timer pins on a 24 hour timing disc determine the sprinkling times and durations. The timer pins engage a trip lever oscillatably journaled about the shaft of a rotary switch which is rotatable continuously in one direction through a series of stable detent positions equally angularly disposed throughout a full 360° turn of the shaft. A pawl carried by the trip lever engages a ratchet wheel on the shaft. The number of teeth on the ratchet wheel is an exact multiple of the number of detent positions for the shaft, and the oscillation amplitude of the trip lever is sufficient to rotate the shaft from one detent position to the next each time a timing pin oscillates the trip lever. The rotary switch has two contact decks, each having an output contact for each group of sprinklers. The output contacts are identically arranged in each deck and the angular spacing between adjacent output contacts is precisely the same as the angular spacing between shaft detent positions. The shaft has a pair of wiper contact members each with one or more wiper contacts arcuately spaced about the shaft and sequentially engageable with the output contacts in their respective decks. The output contacts in one deck are respectively connected to the individual electrically activatable valves to energize and deenergize them in a sequence and for a duration determined by the timing pins. The output contacts in the second deck are all connected to the main electrically activatable valve and the wiper contact or contacts in that second deck are relatively wide enabling them to engage one output contact before disengaging a preceding one to thereby keep the main electrically activatable valve energized during the entire sprinkling cycle. The rotary switch is manually indexed by rotating an index knob on the end of the shaft to override the pawl and ratchet mechanism. Five- and eleven-station controls are illustrated. The basic parameters of 23 different embodiments of the invention are listed, and the parameters are interrelated according to the following formula: S = (N + 1)(360/D) where S = the arcuate spacing of the wiper contacts about the shaft in each deck, in degrees N = the number of output contacts in each deck D = the number of detent positions of the shaft in a full turn.



Inventors:
CALABRESE RONALD V
Application Number:
05/442790
Publication Date:
01/28/1975
Filing Date:
02/15/1974
Assignee:
LUMENITE ELECTRONIC COMPANY
Primary Class:
Other Classes:
137/624.16, 200/11D, 200/17R, 200/37A, 239/69, 307/141, 968/620
International Classes:
A01G25/16; G04C23/30; (IPC1-7): H02J3/00; G05B19/00
Field of Search:
200/11R,11D,14,17R,17A,18,24-27,33R,35R,37R,37A,61.69,291 307
View Patent Images:
US Patent References:
3604943SPRINKLER SYSTEMS AND VARIABLE TIMING MEANS1971-09-14Bayer et al.
3440434APPARATUS FOR PROGRAMMING CYCLIC ACTUATION OF VALVES1969-04-22Yates et al.
3309543Automatic control for sprinkler systems1967-03-14Alston et al.
3140720Fluid distribution control system1964-07-14Griswold
2740056Selective rotary reversing switches1956-03-27Parker et al.
2665964Recording instrument1954-01-12Olah et al.
2594190Electrical apparatus1952-04-22Mastney
1906943Intermittently-operating controlling device1933-05-02Fisher et al.



Primary Examiner:
Scott, James R.
Attorney, Agent or Firm:
Davis, McCaleb & Lucas
Claims:
1. In an automatic sprinkler sequence control apparatus for controlling the operating sequence of a plurality of individual electrically activatable sprinkler components, the improvement comprising:

2. In an automatic sprinkler sequence control apparatus according to claim 1 in which the relationship between said wiper contact means, output contacts, and detent positions of the shaft is

3. In an automatic sprinkler sequence control apparatus according to claim 1 in which said wiper contact means has a plurality of said wiper contacts

4. In an automatic sprinkler sequence control apparatus according to claim 1 having

5. In an automatic sprinkler sequence control apparatus according to claim 4 in which

6. In an automatic sprinkler sequence control apparatus according to claim 5 in which said second wiper contact means has at least one wiper contact

7. In an automatic sprinkler sequence control apparatus according to claim 4 in which each of the first and second wiper contact means has a

8. In an automatic sprinkler sequence control apparatus according to claim 4 including a separate mode selector switch for each of said first connecting means and a corresponding second connecting means, and a second common conductor connecting each switch direct to said electrical power source,

9. In an automatic sprinkler sequence control apparatus according to claim 1 including a separate mode selector switch for each of said first connecting means and a common conductor connecting each switch direct to said electrical power source, each switch being actuatable between manual and automatic mode positions, each switch being effective in the automatic mode position to connect the corresponding individual output terminal to said electrical power source through a corresponding one of said output contacts when the latter is engaged by said wiper contact means, and each switch being effective in the manual mode position to connect said corresponding individual output terminal direct to said electrical power source through said common conductor and thereby bypass said first

10. In an automatic sprinkler sequence control system having:

11. In an automatic sprinkler sequence control system according to claim 10 having

12. In an automatic sprinkler sequence control system according to claim 11 in which

13. In an automatic sprinkler sequence control system according to claim 12 in which the wiper contacts in said other deck are wider than the wiper

14. In an automatic sprinkler sequence control system according to claim 10 in which said shaft is rotatably in said one direction to override said ratchet, and there is a manually operable knob on said shaft effective to rotatably index said shaft in said one direction to a selected position.

15. An automatic sprinkler sequence control system comprising:

Description:
BACKGROUND OF THE INVENTION

The field of invention includes automatically timed control apparatus for use in sequentially energizing and deenergizing electrically activatable components such as valves for automatic sprinkler systems and the like.

Timing control apparatus for sequentially activating components such as solenoid-operated sprinkler valves in the system disclosed here, washing and rinsing and drying operations in dishwashing and laundering equipment, automatic mixers, and the like, conventionally employ a relay-actuated stepping switch to deenergize one function and energize the next at selected times determined by timing elements on a constant speed motor-driven disc. If the apparatus is on a daily cycle, as for example a lawn where groups of sprinklers are turned on and off, one group at a time, every night, the disc rotates once in 24 hours. Timing pins or clips are positioned about the periphery of the disc and these sequentially close and open a switch which applies an electrical impulse to a coil or solenoid in the stepping switch.

Each time a conventional stepper coil is impulsed, it drives a pawl-like plunger or armature to advance a ratchet wheel which is part of the stepping switch. This opens one set of contacts and closes another set to deenergize one electrically activatable component and energize another. The plunger or armature is biased, as by a spring, so that when the stepper coil disengages at the end of the electrical impulse, it returns to cocked position, ready to advance the ratchet wheel in response to the next impulse.

In the conventional stepping switch used in this kind of apparatus, the ratchet wheel rotates forward during an operating cycle and then backward to reset. It does not rotate continuously in the same direction as it goes through repeated cycles. The ratchet wheel is generally rotatably biased by a torsion spring in the direction opposite that which it is rotated by the stepper coil and a pawl normally holds it against backward rotation by the spring. At the end of the operating cycle, a reset coil lifts the pawl, releases the ratchet wheel, and enables the torsion spring to rotate it back against a stop to its starting position ready for the next cycle.

Because of the relatively slow movement of a 24 hour timing disc, the switch energizing the stepper coil is held closed for longer than necessary to produce the impulse needed to advance the stepper switch. To avoid large, expensive, continous-duty stepper coils, small intermittent-duty coils or solenoids may be used with means for limiting current to it. One example is described in applicant's co-pending application Ser. No. 169,924 filed Aug. 9, 1971 on "Automatic Control Apparatus With Thermistor Protected Stepper Coil" where a positive thermal coefficient thermistor is placed in series with the stepper coil. Because attempts to use smaller stepper coils have required current limiting controls, this has simply resulted in trading off one problem for another. If a smaller coil is used, something has to be added to protect it.

Many attempts have been made to produce electrically activated stepping switches for sequence controls but none has been entirely satisfactory from the standpoint of low first cost and reliability. The requirement of stepper and reset coils and all the associated mechanical parts and control circuitry makes a complex, expensive assembly which requires considerable care in manufacture to make it operate reliably, and the cost is too high for wide use in home and garden sprinkling systems.

It has long been recognized by those in this art that an automaic sequencing system would preferably not use any electrically activatable stepping switch at all, but prior to the present invention, no such system has been developed.

BRIEF SUMMARY OF THE INVENTION

Broadly the object of this invention is to provide apparatus for automatically controlling the sequence and duration of a plurality of electrically activatable components, one example being opening and closing electrically activatable valves which control groups of sprinklers, in predetermined time sequence, each for a predetermined duration.

A primary object is to provide in such apparatus a unidirectional rotary switch which is mechanically operated by a timing disc through a trip level and a pawl and ratchet mechanism, thereby eliminating completely the need for an electrically activatable stepping switch previously used in conventional sequence control apparatus.

Another object is to provide such apparatus having a multi-deck rotary switch in which one deck has a wiper contact sequentially engageable with output contacts connected respectively to individual electrically activatable components, and a second substantially similar deck with output contacts all connected to a main electrically activatable component, and in which incremental advance of the rotary switch through successive rotated positions by a timing member successively energizes and deenergizes the individual components through an operating cycle, while maintaining the main component energized for the entire duration of that operating cycle.

Another object is to provide such apparatus which can be manually indexed to a desired portion of a sequencing cycle by merely rotating an index knob without repeatedly depressing levers or buttons.

A specific object is to provide an automatic sprinkler sequence control apparatus having a two-deck rotary switch with a shaft incrementally rotated through pawl and ratchet mechanism by a timing member, the first deck of the rotary switch having a wiper member with one or more relatively narrow contacts each of which is sequentially engageable with output contacts connected respectively to individual sprinkler solenoid control valves, the rotary valve having a second deck similar to the first deck except that the wiper contacts are relatively wider and the output contacts are all connected to a main sprinkler solenoid valve controlling flow through the individual valves, thereby maintaining the main valve open during an entire operating cycle while the individual valves open and close in response to incremental advance of the rotary switch.

Other objects and advantages will be apparent from the following description in connection with the drawings in which:

FIG. 1 is a schematic view of an automatic lawn sprinkler control system illustrating the present invention with some parts fragmentarily shown and a mechanically actuated rotary switch shown in greatly enlarged, exploded perspective;

FIG. 1A is a fragmentary cross section of FIG. 1 taken along line 1A--1A;

FIG. 2 is a side view, partly in vertical cross section, of the rotary switch shown in FIG. 1, in assembled condition;

FIG. 2A is a fragmentary cross sectional view of FIG. 2 taken along line 2A--2A;

FIG. 3 is a cross-sectional view of FIG. 2 taken along line 3--3;

FIG. 4 is a fragmentary enlarged cross-sectional view of FIG. 3 taken along line 4--4;

FIGS. 5--9 are views of the mechanism shown in FIG. 3 in different portions of an operating cycle; and

FIG. 10 is a view similar to FIG. 3 of a modified form of the invention.

Like parts are designated by like reference characters throughout the figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now in detail to the drawings, a piping system is illustrated as it would be provided for watering a lawn, golf course, or agricultural field using an automatic sequence control apparatus employing the principles of the present invention. A main supply conduit 24 is connected with a water source P under pressure. A main electrically activatable valve MV controls the flow of water from the conduit 24. This valve is of the normally closed type and opens when energized or activated as will be described.

Alternatively, supply conduit 24 may be connected to an unpressurized or low pressure source such as a well or standpipe. In such case an electrically activatable pump may be substituted for the valve MV. However, whether the main electrically activatable component MV is a valve or a pump, it is referred to herein as a main electrically activatable component and it controls the flow of water through conduits 28, 29, 31 and 32 to sprinkling conduits 33, 34, 36, 37 and 38. Between each of these sprinkling conduits and main valve MV, there is an individual electrically activatable component in the form of a solenoid valve. Five of these individual solenoid valves are shown, being designated V1, V2, V3, V4 and V5. These individual valves control flow into groups of sprinklers designated S1, S2, S3, S4 and S5, respectively. Each group of sprinklers may comprise any number of sprinklers, only one of which is shown as representative to each group in the present case. The main valve MV and each individual valve V1-V5 has a solenoid actuator 39 which holds the valve open as long as it is energized and enables it to close when deenergized.

A multi-deck rotary switch means is generally designated 41. It has a shaft 42 rotatably journaled in a support frame which includes a journal bushing 43 having external threads 44. The bushing 43 extends through an opening 46 in a panel 47 which is fragmentarily shown in FIG. 2. Lock nuts 48, 49 are screwed onto the threads 44 on opposite sides of the panel 47 and hold the switch firmly in place. The shaft 42 has a C-ring 51 recessed in a groove 52. The C-ring is seated on the end of the bushing 43 and may either rotate with the shaft or may be stationary on the bushing while the shaft rotates within it.

The rotary switch 41 has a detent deck 53 and first and second contact decks 54 and 56, respectively.

The detent deck consists of a stationary plate 57 and a rotatable blade 58. The inner end portion of the shaft 42 has a flat 59 on each side. This is engaged within a rectangular opening 61 at the center of the blade to hold them against relative rotational movement. The blade 58 is staked tightly to the shaft 42 by indentations 62 (FIG. 2) which upset portions 63 of the shaft into engagement with the underside of the blade. The blade has two diammetrically spaced through-holes 64, each with a detent ball 66 loosely held therein and pressed upward by an elongated leaf spring member 67 held against the underside of the blade by rivets 68. The detent plate 57 is formed with a plurality of dimples having downwardly concave detent recesses 69 for engaging the detent balls 68 as shown in FIG. 1A. In the embodiment shown, there are precisely 24 detent recesses 69 evenly arcuately spaced exactly 15° apart in a circular track around the shaft 42. Thus, the detent means acting between the shaft 42 and the frame 40 sequentially retains the shaft in a plurality of evenly arcuately spaced stable detent positions, in this case the arcuate spacing being 15°. As will be described, other embodiments may employ different total numbers of these detent positions and different arcuate spacings between adjacent detent positions, but in all cases they will be evenly arcuately spaced about the shaft.

The first or upper contact deck 54 comprises an outer stationary plate 71 with a circular opening 72 (FIG. 4), and an inner, circular plate 73 with a central rectangular opening 74 engaged with the flatted inner end portion of the shaft 42. Both the plates 71 and 73 are made of material having good electrical insulating characteristics and good mechanical strength such as an electrical grade laminated phenol formaldehyde plastic sheet. As shown in FIG. 4, the inner rotatable plate 73 has, along its outer periphery, an annular flange 76 staked in place and held by tines 77x extending through the plate 73. The flange 76 underlies the plate 71 and with the wiper contact means to be described keeps the plate 73 coplanar with the place 71 while enabling it to rotate freely within the opening 72.

Wiper contact means generally designated 77 consist of an annular wiper ring 78 held firmly in place by tines 79 staked into the plate 73. The outer portion of ring 78 overhangs and engages the top surface of the plate 71 to help retain the plate 73 coplanar with the plate 71. In the embodiment illustrated, there are four wiper contacts 81 comprising integral tabs extending radially from the wiper ring 78 and evenly arcuately spaced about the shaft 42, at 90° intervals. The wiper ring and wiper contacts, of course, will be electrically conductive, preferably metal.

Deck 54 has five output contacts, C1, C2, C3, C4 and C5 sequentially engageable, one at a time, by the wiper contacts 81. These contacts are arranged in precisely 15° increments about the shaft 42, the same as the detent recesses 69, and as will be described, each is connectible to a particular one of the individual solenoid valves V1-V5. The output contacts C1-C5 are circumferentially positioned to match the detent positions of the wiper contact means so that when any of the wiper contacts 81 is engaged with one of the output contacts, the wiper contact means 77 is in one of its 24 stable detent positions. Furthermore, the five output contacts are all spaced 15° apart so any of the wiper contacts 81 successively engages all of the output contacts C1-C5 as the wiper contact means is moved through successive detent positions. In addition to the output contacts just described, stationary plate 71 has a longer contact 82 engaging the main annulus of the wiper ring 78 at all times. As will be described, this is a common contact, bringing one side of an electrical power source direct to the wiper contact means.

The second, lower contact deck 56 is shown as identical in all respects with the above described deck 54 except for one important inventive feature, namely that the wiper contacts 81a are wider (circumferentially) than contacts 81. Because of this identity between parts, the parts in deck 56 will be identified by the same reference indicia followed by the letter "a". For example, the five output contacts corresponding to C1, C2, C3, C4 and C5 are identified C1a, C2a, C3a, C4a and C5a.

The circumferential width of the wiper contacts 81 in deck 54 is such that the wiper contact 81 disengages from each of the output contacts before engaging the next. As will be seen, this enables each individual valve V1-V5 to close before the next is opened, avoiding concurrent operation of two groups of sprinklers when the system is in straight automatic mode.

As will also be seen when the circuit connections are described, the second deck 56 controls operation of the main valve MV. By making the wiper contacts 81a wider as shown, they will span the distance between adjacent contacts and engage one output contact before disengaging an adjacent preceding one. This keeps the main valve MV open for the entire sprinkling cycle, opening concurrently with individual valve V1 and closing concurrently with closing of individual valve V5. This avoids starting and stopping of flow through the main valve MV during change-over from one group of sprinklers to another. Among other advantages, this minimizes destructive water hammer when the water flow stops.

The rotary switch 41 is assembled by a pair of bolts 83 and 84 extending through openings 86 in plates 57, 71 and 71a. The bolts are held by nuts 87 and washers 88 and the parts are held in proper spaced relation by spacer bushings 89.

The mechanism for actuating the rotary switch to cause the first and second wiper contact means 77 and 77a successively to engage corresponding pairs of first and second output contacts C1-C5 and C1a-C5a will now be described.

A ratchet wheel 91 is mounted on and rotatable with the shaft 42 by a set screw 92. At the outer end of the shaft, a manual advance knob 93 is fastened by a pin 94. A trip lever 96 is positioned between the knob and ratchet wheel and is oscillatably journaled for back and forth swinging movement about the shaft. A pawl 97 is pivoted on a pin 98 at one end of the trip lever. As shown in FIGS. 1 and 2A, the pawl is urged counterclockwise about the pin 98 and the trip lever is urged clockwise about the shaft against a stop 99 by a tension spring 101 which is fastened between pin 102 on the pawl and a fixed pin 103 fastened to the frame. Note in FIG. 2A that the line of action of the spring 101 is to the right of the pin 98.

There are precisely 24 teeth 104 on the ratchet wheel 91, corresponding to the 24 detent positions 69 of the shaft so that one back and forth oscillation of the trip lever engages one of the teeth 104 and advances the shaft 15° from one detent position to the next. Alternatively, the ratchet wheel may have 48 teeth in which case the pawl will advance it two teeth per oscillation of the trip lever; or the ratchet wheel may have 72 teeth in which case the pawl will advance it three teeth at a time; etc. The general rule is that the number of teeth on the ratchet wheel is an even multiple of the number of detent positions of the shaft.

By manually rotating the knob 93 in a counterclockwise direction, the shaft 42 will override the pawl and ratchet mechanism enabling the wiper contact means 77 and 77a to be manually indexed quickly and easily to set the rotary switch in the proper portion of the control cycle.

Timing means which oscillate the trip lever 96 at selected times to determine the operating time and duration for each of the individual valves V1-V5 will now be described.

A timing disc 106 is rotated once in 24 hours by motor 107 through speed reducing gearing illustrated by the pinion 108 and gear 109. The motor drives the pinion through shaft 111 and the gear drives the timing disc through a shaft 112. It will be understood that this is merely a schematic representation of any suitable arrangement for driving the timing disc 106 at constant speed which, depending upon the application, rotates the timing disc completely during some suitable time period.

About the periphery of the timing disc, there is a series of evenly arcuately spaced openings 113 for the selective placement of timing pins P1, P2, P3, P4, P5 and P6. As one specific example, the timing holes 113 may be spaced fifteen minutes apart and the timing pins P1-P6 may be placed in suitable holes to turn the sprinklers S1-S5 on and off late at night when loss of water by evaporation is minimized.

In practical application of this invention, the components described above, except for the piping valves and sprinklers, will be housed in a control case (not shown) at a control station or some protected, accessible location. In addition, the housing will contain a source of electrical power, here shown as a 110 volt/24 volt step-down transformer 114; and indicator lamp 116; station mode selector switches K1, K2, K3, K4 and K5 for selecting "automatic", "manual" and "off" positions or modes for each of the individual sprinkler control valves V1-V5; and a main switch KM.

A common output terminal TC is connected to one input terminal of each solenoid valve MV and V1-V5 through conductors 117, 118, 119, 121, 122, 123 and 124.

A main output terminal TV is connected through conductor 126 to another input terminal of main valve MV.

Output terminals T1, T2, T3, T4 and T5 are connected respectively to another input terminal of each individual solenoid valve V1-V5 through conductors 127, 128, 129, 131 and 132.

Two main power input terminals L1 and L2 are connected to an external 110 volt alternating current power source.

Main switch KM and mode selector switches K1-K5 are preferably slide switches having a slide button with right and left closed positions and a center open position. More specifically, these are illustrated as double pole, double throw switches. Each is illustrated with a pair of movable contacts 1 and 2, right-hand stationary contacts 3 and 4, and left-hand stationary contacts 5 and 6.

In the embodiment illustrated, the timing motor 107 is powered by the 110 volt inputs L1-L2. L1 is connected directly to timing motor 107, and to the primary of transformer 114, through conductors 133 and 134, respectively. Main switch KM is in the "on" position for automatic or manual operation when movable contacts 1 and 2 engage contacts 5 and 6. Main switch KM is in "rain" position when contacts 1 and 2 engage contacts 3 and 4. In the "on" position L2 connects through conductor 136 and fuse 137 to the primary of transformer 114, and through conductor 138 to the timing motor 107. In the rain position, L2 is connected through conductor 139 and fuse 137 to the transformer and again through conductor 138 to the timing motor.

When main switch KM is in the on position, one power output terminal 141 of the transformer 114 secondary is connected through conductor 142, contact 5, and output terminal TC to one input terminal of each of the valves MV and V1-V5; and power output terminal 141 is also connected to one side of indicator lamp 116 through conductor 143. The other power output terminal 144 of transformer 114 is connected in common through conductors 146, 147 and 148 to all of the contacts 5 and 6 of switches K1-K5 and to the wiper contact means 77 and 77a through common output contacts 82 and 82a. In the individual switches K1-K5 each contact 1 is connected to a corresponding output terminal T1-T5 through conductors 149, 151, 152, 153 and 154, respectively. All of the movable contacts 2 are connected through a common conductor 156 and conductors 157 and 158 to the lamp 116 and main output terminal TV. The stationary contacts 3 are connected to the first deck output contacts C1-C5 through conductors 159, 161, 162, 163 and 164, respectively. Stationary contacts 4 are connected to the second deck output contacts C1a- C5a through conductors 166, 167, 168, 169 and 161, respectively.

An important feature of the present invention is that the rotary switch rotates in one direction only and never reverses direction to reset as in the case with conventional relay actuated stepping switches commonly used in sequencing apparatus.

Before describing other embodiments including the eleven-sprinkler embodiment partly shown in FIG. 10, use and operation of the system shown in FIGS. 1-9 will be described for both manual and automatic modes.

Assume the following positions of the components at the beginning of the operating cycle:

a. Main switch KM is in on position with movable contacts 1 and 2 engaging contacts 5 and 6, respectively;

b. All selector switches K1-K5 are in their "automatic" positions, with movable contacts 1 and 2 of each engaging contacts 3 and 4, respectively;

c. Timing pins P1-P6 are in 2:00 A.M., 2:15 A.M., 2:30 A.M., 2:45 A.M., 3:00 A.M. and 3:15 A.M. positions, respectively, around the periphery of timing disc 106 which is positioned so the next pin to engage trip lever 96 will be P1;

d. The shaft 42 is indexed to the "off" position shown in FIG. 5 where two of the four wiper contacts 81 an 15° away, clockwise and counterclockwise, respectively, from the output contacts C1 and C5. As stated, the shaft 42 may be advanced manually, counterclockwise, by turning knob 93 to index the wiper contacts to this particular position.

The four wiper contacts 81 in the first deck 54 are at 90° arcuately spaced positions. It will be understood that the corresponding wiper contacts 81a in the second deck 56 will be in exactly corresponding positions below wiper contacts 81. With the components in the positions assumed in "a" through "d" above, the timing motor 107 will be energized from L1 to L2 through conductors 133, 138, 139 and 136, and contacts 6 and 2. This rotates the timing disc 106. Pin P1 engages trip lever 96 and oscillates it about the axis of shaft 42. Pawl 97 and ratchet wheel 91 rotate counterclockwise. Detent balls 66 are moved out of one diametrically opposed pair of detent recesses 69 (FIG. 1A) toward an adjacent pair of recesses 69. Intermediate the two adjacent detent recesses, the balls move across overcenter high points 172 (FIG. 1A). Slightly beyond there, the upward pressure of the leaf spring member 67 against the balls, and the sloping surface 137 into the next detent recess causes the shaft and wiper contact assemblies to move ahead to the next detent position by snap action. In other words, just beyond the high point 172 there is an overcenter action which tends to snap the shaft forward to the next stable detent position in which the balls 66 are seated in corresponding recesses 69. As will be described, for some of these detent positions the wiper contacts 81 and 81a will be engaged with output contacts C1-C5 and C1a-C5a to energize the sprinkler control valves. Following the snap action movement described, the pin P1 continues to move against the hook end of the trip lever 96. When it passes that end, the spring 101 pulls the trip lever back, clockwise, against stop 99 to a starting or cocked position ready to advance the ratchet wheel one more tooth when the trip lever is again moved by the next timing pin.

As described above, timing pin P1 rotatably advanced shaft 42 one detent position, that is 15°, from the off position of FIG. 5 to the FIG. 6 position. One of the wiper contacts 81 engages output contact C1. Similarly, one of the wiper contacts 81a engages output contact C1a. This energizes and opens main valve MV and individual valve V1 directing flow through sprinkler group S1 by activating the circuit as follows.

One power input terminal of each of main valve MV and individual valve V1 is connected to output terminal 141 of transformer 114 through conductors 117, 119 and 118, common outputterminal TC, contacts 5 and 1 of main switch KM, and conductor 142. The other power input terminal of main valve MV is connected to the other output terminal 144 of transformer 114 through conductor 126, output terminal TV, conductor 156, contacts 2 and 4 of switch K1, conductor 166, output contact C1a, wiper ring 78a and common contact 82a in the second contact deck, and conductors 147 and 146. And the other power input terminal of individual valve V1 is connected to the other power input terminal 144 of transformer 114 through conductor 127, output terminal T1, conductor 149, contacts 1 and 3 of switch K1, conductor 159, output contact C1 and wiper ring 78 and common contact 82 in the first contact deck, and conductors 148 and 146.

At the same time, the indicator lamp 116 is lighted. One side is connected to transformer output terminal 141 through conductor 143. The other side is connected to the other transformer output terminal 144 through conductors 157 and 156, contacts 2 and 4 of switch K1, conductor 166, output contact C1a and wiper ring 78a and common contact 82a in the second contact deck, and conductors 148 and 146.

Thus, summarizing the above, as timing pin P1 moves trip lever 96 at 2:00 A.M. in the example given, main valve MV and individual valve V1 open simultaneously, directing water to the group of sprinklers S1. Lamp 116 lights to show that sprinkling is in progress.

At 2:15, 2:30, 2:45, 3:00 and 3:15, respectively, timing pins P2, P3, P4, P5 and P6 engage the trip lever 96 and successively index the rotary switch to the FIG. 7, FIG. 3, FIG. 8, FIG. 9 positions, and finally to a new off position identical to FIG. 5 except that the wiper rings 81 and 81a have been rotated 90° counterclockwise. In other words, wiper contacts 81 (and corresponding wiper contacts 81a) are again at the A and B positions indicated in FIG. 5. This successive automatic indexing of the shaft and wiper contact means 77 and 77a resultts in the following specific activation sequence for the individual valves V1-V5 at 15 minute intervals:

Deenergizes valve V1 and energizes valve V2 at 2:15 A.M.

Deenergizes valve V2 and energizes valve V3 at 2:30 A.M.

Deenergizes valve V3 and energizes valve V4 at 2:45 A.M.

Deenergizes valve V4 and energizes valve V5 at 3:00 A.M.

and finally simultaneously deenergizes valves V5 and MV at 3:15 A.M.

By moving any mode selector switch K1 through K5 to "manual" position, that is, by engaging movable contacts 1 and 2 with contacts 5 and 6, respectively, the corresponding valve V1 through V5 will be activated simultaneously with the main valve Mv, and lamp 116 will be lighted. For example, by moving switch K1 to manual position, the main valve MV is connected to the output terminal 144 of transformer 114 through conductors 126, 158 and 156, contacts 2 and 6 of switch K1, and conductor 146.

By placing main switch KM in "rain" position, that is, engaging contacts 3 and 4, the timing motor 107 will continue to drive disc 106 and keep it properly timed, but none of the sprinkler valves will be energized.

As explained above, the first deck wiper contacts 81 are relatively narrow and disengage each output contact C1-C5 before engaging the next, while the second deck wiper contacts 81a are relatively wider and disengaged one output contact only after engaging the next. This results in an operating cycle in which each sprinkler group S1-S5 is shut off at least momentarily before water is directed to the next group, while valve MV stays open for the entire operating cycle beginning with the opening of valve V1 until the closing of valve V5.

During each operating cycle, operating at 2:00 A.M. and ending at 3:15 A.M. in the example given, with the timer pin settings shown, the shaft 42 rotates the wiper rings 90° per cycle, from the off position shown in FIG. 5 to a next position which is just the same except that each wiper contact means is rotated 90° counterclockwise. In each operating cycle the active wiper contact 81 (and 81a) moves counterclockwise 90° from position A to position B.

As illustrated in FIG. 5, the five output contacts C1-C5 span an arc of 60° enabling the wiper contacts 81 to flank the end contacts C1 and C5, 15° away from either, in the off position. Likewise, the five output contacts C1a-C5a span the same 60° arc and two wiper contacts 81a flank end contacts C1a and C5a 15° away from either. There are four such positions, of course, one for each of the wiper contacts when in position A. Thus, with one operating cycle per rotation of the 24 hour timing disc 106, it takes 4 days for the shaft 42 to rotate the wiper rings one full turn. By using each wiper contact 81, and 81a, only one-fourth of the time, and with a single off position as shown in FIG. 5 between operating cycles, the wiper rings can rotate continuously in the same direction without reversal for reset. At the end of each sprinkling cycle, at 3:15 A.M. in the example given, the wiper ring asembly stops with one of the four wiper contacts 81 in position A, only 15°, one detent position, away from the restart position for a new cycle shown in FIG. 6.

FIG. 10 shows how the wiper contact assembly of FIG. 3 may be modified for use with an eleven-sprinkler system. Eleven wiper contacts C101 through C111, in the first deck, are spaced 15° apart, making a total span of 150°. The wiper ring 178 has in this case only two wiper contacts 181 spaced 180° apart. The second deck is not shown, because it would be identical except that the wiper contacts would be somewhat wider for th purpose described in connection with wiper contacts 81a, namely, to keep the main valve open during the entire sprinkling cycle. The eleven-sprinkler wiper arrangement of FIG. 10 has two off positions in which the contacts 181 are in positions AA and BB, each being 15°, one detent position, away from an end output contact C101 or C111. Thus, each wiper assembly would rotate 180° per operating cycle, taking two days to rotate a full turn.

An eleven-sprinkler system controlled by a rotary switch as shown in FIG. 10 would be exactly the same as the five-sprinkler embodiment in FIG. 5 except, of course, there would be more individual valves, sprinklers and manual/automatic mode selector switches.

The invention may be applied to systems having other numbers of sprinklers and electrically activatable components other than the five- and eleven-sprinkler embodiments specifically described. In each case, and referring to examples of components in FIG. 1, the wiper contacts 81/81a, and the detent positions corresponding to detent recesses 69, must be equally arcuately spaced about the axis of the shaft 42. The number of teeth in the ratchet wheel 91 must be an even multiple of the number of detent positions. The output contacts C1-C5/C1a-C5a must be arcuately spaced apart in amounts corresponding to the arcuate spacing between adjacent detent positions; in other words, if there are 24 detent positions, 15° apart, the output contacts must be 15° apart. And the number of active output contacts C1-C5/C1a-C5a must equal the number of individual sprinkler valves V1-V5.

Within the criteria stated in the paragraph above, the interrelation of basic parameters for an automatic sequence control apparatus according to the present invention may be expressed by the following formula:

S = (N + 1) (360/D)

where

S = the arcuate spacing of the wiper contacts about the shaft in each deck, in degrees,

N = the number of active output contacts in each deck, and

D = the number of detent positions of the shaft evenly arcuately spaced in a full turn.

Using the above formula, the basic parameters for some examples of sprinkler systems having from 2 to 23 sprinklers are listed as follows: N D S No. of Evenly Angular Spacing No. of Sprinklers No. of Evenly Spacing in Arcuately Between Adjacent & No. of Active Arcuately Spaced Degrees Spaced Wiper Detent Positions Output Contacts Detent Positions Between Contacts (Same As Between in Eact Rotary Wiper Adjacent Output Switch Deck Contacts Contacts), In Degrees __________________________________________________________________________ 2 18 60 6 20.0 3 24 60 6 15.0 4 30 60 6 12.0 5 30 72 5 12.0 5 24 90 4 15.0 6 27 90 4 13.3 7 24 120 3 15.0 8 27 120 3 13.3 9 30 120 3 12.0 10 22 180 2 16.3 11 24 180 2 15.0 12 26 180 2 13.8 13 28 180 2 12.8 14 30 180 2 12.0 15 32 180 2 11.3 16 34 180 2 10.6 17 36 180 2 10.0 18 38 180 2 9.5 19 40 180 2 9.0 20 42 180 2 8.6 21 44 180 2 8.2 22 46 180 2 7.8 23 24 360 1 15.0 __________________________________________________________________________

In the last example above, the single wiper contact is sapced 360° with respect to itself, thus demonstrating that the formula applies even to a single wiper contact in each deck.

While five- and eleven-sprinkler embodiments have been specifically disclosed and the basic parameters for other systems using from two to twenty-three sprinklers have been listed, it will be understood that various modifications and applications may be made within the spirit and scope of the invention which should be limited only by the appended claims. For example, it should be clearly understood that the invention may be applied to sprinkling systems having individual valves V1-V5 with no main valve MV, in which case the invention could be practised using a single wiper contact deck 54.