Automatic Sprinkler System

Abstract

A system for controlling the operation of a plurality of sprinklers distributed over an area to be irrigated includes a timer clock wheel mounting a plurality of indexer clips which successively actuate a photoelectric switch located below the clock wheel. The photoelectric switch controls the on-off operation of the variously located sprinklers in succession in accordance with the time positions of the indexer clips.

Description

The present invention relates to automatic sprinkler systems and more particularly to sprinkler system incorporating electronic timer control techniques for automatically controlling the duration and sequence of operation of a plurality of sprinklers widely distributed at various stations in an area to be irrigated.

Presently known lawn sprinkler systems for irrigating large ground areas generally employ a plurality of sprinklers distributed at various stations over the ground area to be irrigated. Such known sprinkler systems often employ electrical timer controls for selectively activating these variously-stationed sprinklers in a preselected sequence and for preselected durations. The timer controls generally employed in such known systems are, generally speaking, similar to the conventional electrical timer clocks widely used in households and commercial applications for turning lights or appliances on and off, in that such timer clocks comprise an electric clock provided with a mechanical trip mechanism for opening and closing the electrical circuits involved.

An important disadvantage of such mechanical trip mechanisms is that they are inherently inaccurate due to mechanical "drag." Furthermore, if in frequent use, the frictional wear on the mechanical trip fingers as well as the associated supporting switch mechanism introduces further inaccuracies in the timing of the system and renders the control system unreliable.

It is therefore an object of the present invention to provide an automatic sprinkler control system which overcomes the above described disadvantages of presently known sprinkler systems.

Another object of the present invention is the provision of an automatic sprinkler control system of the character described incorporating a timer control employing electronic switching means.

In accordance with the principles of the present invention there is provided a system for controlling the operation of a plurality of sprinklers distributed over an area to be irrigated. The system of the present invention comprises clock means and photoelectric switch means connected to the sprinkler valves, and being operative, in response to the interruption of the impingement of light energy thereon, to actuate the sprinkler valves. For this purpose, indexed trigger means are affixed to the clock means at preselected time positions thereon for interruption of light impinging on the photoelectic switch to thereby effect actuation of the various sprinklers in a preselected sequence and duration in accordance with the programmed indexed trigger means.

Additional objects and advantages of the present invention will become apparent during the course of the following specification when taken in connection with the accompanying drawings, in which:

FIG. 1 is a schematic view of an installation employing a multi-station sprinkler system in accordance with the present invention;

FIG. 2 is a top plan view of the control panel of a sprinkler control system in accordance with the principles of the present invention;

FIG. 3 is an enlarged sectional view taken along the line 3--3 of FIG. 2;

FIG. 4 is an enlarged sectional view taken along the line 4--4 of FIG. 2;

FIG. 5 is a schematic circuit diagram of the electrical control system employed in the system of FIG. 2, showing the incorporation of the electronic switching circuit of FIG. 6; and

FIG. 6 is an electrical schematic diagram of the electronic switching circuit employed in the system of FIG. 2.

Referring in detail to the drawings, and in particular to FIG. 1, in a typical sprinkler installation a plurality of sprinklers are installed in the ground 12 at various locations. Two such sprinklers 10 and 11 are shown in FIG. 1 by way of example, with sprinklers 10 and 11 being connected to a suitable water main 14. Sprinklers 10 and 11 are each provided with solenoid-actuated valves 15 and 16 respectively. Sprinkler valves 15 and 16 are controlled by electrical switching means housed in a control box 18, remote from sprinklers 10 and 11 and connected to the solenoid valves 15 and 16 by an electrical cable 19 which comprises the leads from each sprinkler valve to control box 18.

FIG. 2 illustrates the layout of the various controls on control panel 20 of control box 18. The control system of the present invention includes a clock wheel 22 mounted on the driven shaft 23 of a clock motor 24 (FIG. 5). The clock wheel 22 has on its dial face twenty-four evenly-spaced calibrations 25, each numbered to represent the twenty-four hours in the day, and marked in the manner shown in FIG. 2 to indicate the twelve hours from noon to midnight, and the twelve hours from midnight to noon. Between each of the hour calibrations 25 are three equally-spaced sub-calibrations 26 dividing each hour into quarters or fifteen minute periods. The clock motor 24 is adapted to turn clock wheel 22 through one complete revolution each day.

Also mounted on control panel 20 is a calendar sprocket wheel 30 provided with fourteen equally-spaced sprockets or fingers 32 projecting radially therefrom. The sprocket wheel 30 is mounted for free rotation upon a central shaft 33 affixed to the face of control panel 26 and upstanding therefrom. The sprocket fingers 32 correspond to the days in a two-week period, and are marked consecutively with the days in each week, as indicated in FIG. 2.

A flat spring 31, mounted on the control panel 20 by screws 33, resiliently engages a pair of the sprocket fingers 32 of calendar wheel 30. This spring 31 serves as a detent to provide stepped rotation of the sprocket calendar wheel 30 in increments of one sprocket finger at a time.

The sprocket calendar wheel 30 is mounted adjacent to the driven clock wheel 22 for periodic actuation by the latter through a trip finger 34 affixed securely to and projecting radially from clock wheel 22. The free end of the trip finger 34 is located in the path of the ends of sprocket fingers 32, so that as clock wheel 32 rotates in the direction of arrow 36 in FIG. 2, that is in a clockwise direction, the trip finger 34 will engage one of the sprocket fingers 32 and turn the calendar wheel 30 in a counter-clockwise direction, as indicated by arrow 37, through an angle corresponding to the width of one sprocket finger 32. Thus, the driven clock wheel 28, which indicates the time of day, will advance calendar wheel 30 by one day increments once every 24 hours.

As shown in FIGS. 1 and 3, and as will hereinafter become apparent in the description of the electrical circuitry shown in FIG. 5, calendar wheel 30 is provided with a circular row of through apertures 38 inwardly of and registering with the respective sprocket fingers 32, each aperture 38 being adapted to receive and mount a removable pin on screw 39 therein. As shown in FIG. 3, the selectively-insertible pins or screws 39 have shanks 39a which depend below the calendar wheel 30 and are positioned to engage and depress the spring arm 41 of a microswitch 40 mounted on control panel 20. As will be presently explained, actuation of the micro-switch 40 deenergizes the sprinkler cycle circuit, so that the sprinkler operation is omitted for any day of the two week watering period for which a pin 39 is inserted.

Clock wheel 22 is also provided with a circular row of through apertures 42, one of said apertures 42 being located in alignment with each of the hour and quarter-hour calibrations 25 and 26. As shown in FIG. 4, each aperture 42 is sized to receive and removably mount an indexing pin 44. Each indexing pin 44 comprises a threaded head 44a for screw mounting in a selected aperture 42 of clock wheel 22, and a thin elongated shank 44b which depends below clock wheel 22. Upon rotation of clock wheel 22, indexing pins 44 are adapted to actuate photo-electric detector switch 46 located beneath wheel 22 adjacent the time reference arrow 48. Switch 46, when actuated by successive pins 44 passing therethrough, is operative to open and close preselected sprinkler valves, such as the valves 15 and 16, in accordance with the settings of the corresponding three-position switchs S-1 through S-5 shown on panel 20, each of which switches control a specific sprinkler.

Switches S-1 through S-5 are operative to control the successive operation of each of the sprinklers at the various stations in the system, depending upon the selective insertion of indexing pins 44 in apertures 42 of clock wheel 22. For example, assuming that switch S-1 corresponds to sprinkler 10, and that switch S-1 is in the "AUTO" position, i.e. the automatic operation mode, as shown in FIG. 2, switch 46 is actuated during the passage through photo-electric detector switch 46 of the first indexing pin 44 in a sequence to turn on sprinkler 10 automatically.

Assuming that switch S-2 corresponds to sprinkler 11 and is also in the "AUTO" setting, the passage through switch 46 of the second indexing pin 44 in the sequence will turn off sprinkler 10 and turn on sprinkler 11. The sequence will be repeated successively for the remaining sprinklers in the system, so long as their control switches are in the "AUTO" setting. However, assuming that switch S-2 is in the "MAN," i.e. manual mode, or in the "OFF" setting, then although sprinkler 10 will operate automatically for the period of time determined by the spacing between the first two indexing pins 44 in the sequence, sprinkler 11 will not be affected by the clock wheel 22, but will remain inactive for the period of time determined by the spacing between the second and third indexing pins 44 in the sequence.

As shown in FIG. 2, there is provided on control panel 20 an additional override switch 49 having an "AUTO" position which allows the system to operate automatically when either of switches S-1 through S-5 are in the "AUTO" mode, and a "RAIN" position for shutting off the system and inhibiting operation of all the sprinklers if it is raining.

DESCRIPTION OF ELECTRICAL CIRCUITRY

Reference is now made to FIG. 4 for a detailed description of the structure and principles of operation of detector switch 46, which, as previously noted is operative to detect the passage of an indexing pin 44 thereacross, and in response thereto to actuate suitable switching apparatus to selectively turn on and off the appropriate sprinkler valve. Detector switch 46 includes a light source 50 operative to emit a light beam 52 across a gap 54 through which successive indexing pins 44 pass upon rotation of clock wheel 22. Light source 50 is partially enclosed in a protective housing 56 having an aperture 58 in a side wall thereof to thereby define light beam 52 therethrough. At the other end of gap 54 is located a photo-electric cell 60 for detecting light beam 52 impinging thereon across gap 54. Cell 60 is mounted in a housing 62 having an aperture 64 of a diameter less than the thickness of pin shank 44b, opening onto gap 54, and in line with light beam 52 passing through the opposed aperture 58.

Thus, when an indexing pin 44 does not block light beam 52, light energy from beam 52 impinges on photo-electric cell 60 thereby generating a voltage at the surface thereof to cause an electrical current to flow through leads 66a and 66b for purposes which will hereinafter become apparent in the description of FIGS. 5 and 6. However, when a pin 44, in its path through gap 52, interrupts light beam 52, the impingement of light energy on photo-electric cell 60, and the flow of current in leads 66a and 66b is cut off.

FIG. 5 illustrates schematically the elements of the electrical control system which are contained in control box 18. It will be seen therein that each of the switches S-1 through S-5 as well as switch 49 are identical, each constituting a three-position slide switch having a total of eight switch contacts a to h and a slide contact 67 defining the "OFF," "AUTO" and "RAIN" positions for switch 49 and the "OFF," "AUTO" and "MAN" positions for switches S-1 through S-5. The slide contacts 47 for all these switches are shown in the "OFF" position in FIG. 5, that is connecting contacts e, f and contacts a, b. To obtain the automatic operation now to be described, the slide contact 67 of the switch 49 will be moved to the "AUTO" position, and the slide contacts 67 of one or all of the switches S-1 through S-5 will also be moved to the "AUTO" position, depending upon which sprinklers are desired to be operated.

Thus, assuming that switch 49 is in the "AUTO" position, power input terminals 69 and 70 are connected to an ordinary household 110 volts A.C. 60 cycle line to thereby energize clock motor 29 via leads 74 and 76. Thus, a 110-volt A.C. potential is applied across the primary winding 78 of transformer 80 to thereby apply a 24 -volt A.C. potential across secondary winding 82, which in turn is applied to photo-electric detector switch 46 as hereinafter described in detail. As previously noted, photo-electric detector switch 46 is operative to detect the passage of an indexing pin 44 therethrough and to produce an output pulse in response thereto across its output leads 84 and 86, which are connected to a solenoid drive 88 having a plunger 90 which is mechanically coupled to the wiper arm 92 of rotary step switch 94.

Rotary step switch 94 is provided with a plurality of terminal contact positions including an OFF position contact as shown and an additional number of contact positions C-1 through C-5 corresponding to the number of sprinklers to be controlled by the control system of the present invention. Thus, in the present example, contact positions C-1 through C-5 are shown corresponding to switches S-1 through S-5 in FIG. 2.

Each time an indexing pin 44 passes through the photo-slectric detector switch 46, the wiper arm 92 of rotary step switch 94 is automatically rotated counter-clockwise by one contact position. Thus, when switch 49 and switches S-1 through S-5 are all set in the AUTO position, and the first pin 44 in a series (for example pin 44' in FIG. 2) passes through detector switch 46, wiper arm 92 will be moved from the OFF position shown in FIG. 5, into engagement with contact C-1 to supply an energizing voltage of 24 volts AC through lead L-1 to the connected sprinkler valve, for example valve 15 of sprinkler 10 shown in FIG. 1. The manner in which this is accomplished will now be described.

Lead 96, connecting switch contact 49b to secondary winding 82 of transformer 80, supplies said contact 49b with 24 volts AC, thereby making available a 24-volt AC voltage on switch contact 49c when slide contact 67 of switch 49 is in the AUTO position. A lead 98 connects switch contact 49c to SKIP-A-DAY microswitch 40 which comprises a normally closed contact 40a and a normally open contact 40b, as shown. Wiper arm 92 of rotary switch 94, is connected to the normally closed contact 40a of switch 40 via lead 100. Furthermore, each of the contact positions C-1 through C-5 of switch 94 is connected via leads 101, 102, 103, 104 and 105 respectively, to the f contacts of switches S-1 through S-5 respectively.

With switch S-1 in the AUTO position, when wiper arm 92 is moved to the C-1 position, a 24 VAC voltage is available at contact f of switch S-1 through lead 101, and therefore at contact g of switch S-1 through its slide contact 67. Contact g in turn applies this voltage, via lead L-1 to the solenoid valve 15 of the corresponding sprinkler 10 to actuate the latter and provide a sprinkling period until the next pin 44" of the series passes through detector switch 46. At this time, the wiper arm 92 advances from contact C-1 to contact C-2, which cuts off the energizing voltage from switch S-1, interrupting the operation of sprinkler 10, and applies the energizing voltage to contact f of switch S-2. This voltage is in turn applied through contact g of switch S-2 and lead L-2 to the next sprinkler in the system, for example to valve 16 of sprinkler 11. This stepped operation continues for each of the five sprinklers in the system, by virtue of the successive actuation of each of the remaining switches S-3 through S-5.

As shown in FIG. 2, there are six indexing pins 44 in each sequence on clock wheel 22. The last pin in the sequence moves the wiper arm 92 back to the OFF position, where it remains until the first indexing pin 44 of the next sequence on clock wheel 22 passes through detector switch 46 to begin a new cycle of operation.

It will be seen that when switch 49 is in the OFF or RAIN position as shown, the 24 VAC voltage necessary for actuating the sprinkler valves will be cut off from lead 98 and hence, from wiper arm 92, and, accordingly, irrespective of the switch positions of switches S-1 through S-5, the 24 VAC valve actuation voltage will be absent from output leads L-1 to L-5, so that the sprinklers in the system are not operated. In addition, when switch 49 is in the OFF position, the 110 volt energizing current for clock motor 29 is cut off, so that the clock wheel 29 is stopped.

For manual operation of the sprinklers corresponding to switches S-1 through S-5 respectively, switch 49 is set at the AUTO position, thereby applying, via lead 106, the 24 VAC voltage on contacts h and d in each of switches S-1 through S-5. Accordingly, when, for example, switch S-1 is in the MAN (i.e. manual) position, the 24 VAC voltage appearing on the h and d contacts thereof is applied, by means of the setting of slide contact 67, to the g contact which is connected to output lead L-1. The foregoing remarks relating to the MAN (i.e. manual) position for switches S-1 is equally applicable to switches S-2 through S-5.

DETECTOR SWITCH 46

Referring to FIG. 6, detector switch 46, as previously noted, comprises a photoelectric cell 60 operative to detect light beam 52 emanating from light source 50 and to produce a voltage across its output leads 66a and 66b in response thereto. Light source 50 which may suitably comprise an incandescent lamp, is connected across secondary winding 82 of transformer 80 by means of leads 108 and 110 and current limiting resistor 112. Additionally, a resistor 114 is connected between lead 66b and the junction of lead 74 and primary winding 78.

A suitable neon gas tube 116 is connected across photoelectric cell output leads 66a and 66b, whereby upon energization of cell 60 by virtue of the impingement of light thereon, gas tube 116 is energized to emit a radiant glow therefrom, which, in turn, is detected by another photoelectric cell 118 in proximity thereto.

The 24 VAC voltage producted at secondary winding 82 is half-wave rectified by means of diode 120 having its anode connected to upper lead 82a of secondary winding 82, a resistor 122 in series with diode 120 and capacitor 124 connected between resistor 122 and lower lead 82b of secondary winding 82. Accordingly, there is produced across capacitor 124 a substantially constant d.c. voltage for selective application to solenoid 88 in response to energization of photoelectric cell 118 as hereinafter described.

In order to selectively apply the d.c. voltage across capacitor 124 to solenoid 88, gate controlled rectifier 126 has its anode 128 connected to the junction of resistor 122 and capacitor 124, its cathode 130 connected to the upper lead 84 of solenoid 88, and its gate electrode 132 connected to the output lead 134 of photoelectric cell 118.

Furthermore, a resistor 136 is connected between the gate 132 and cathode 130 of rectifier 126, and a diode 138 is connected across solenoid winding 88.

As is well known to those skilled in the art, when a d.c. voltage of suitable polarity is applied between the cathode and anode of a gate controlled rectifier, if a suitable pulse is applied to the gate electrode, it will serve to latch the rectifier into conduction.

Thus, when an indexing pin 44 actuates photoelectric cell 60, thereby actuating photoelectric cell 118 as described hereinabove, the photoelectric voltage produced across output leads 134 and 135 of cell 118, is applied between the gate 132 and anode 128 of rectifier 126, thereby biasing rectifier 126 into the latched conduction state. In such conduction state, rectifier 126 presents a substantially short circuit condition in its cathode to anode path, whereby the voltage across capacitor 124 is applied to solenoid winding 88, thereby energizing solenoid 88, and as previously noted, actuating plunger 90 and causing step switch 94 to advance to the next station contact. In this way, passage of each indexing pin 44 causes the advance of step switch 94 to the next station contact, thereby actuating the corresponding sprinkler, as previously explained.

While a preferred embodiment of the invention has been shown and described herein, it is obvious that numerous omissions, changes, and additions may be made in such embodiment without departing from the spirit and scope of the invention.

Claims

What is claimed is:

1. A system for controlling the operation of a plurality of sprinklers distributed over an area to be irrigated comprising clock means including a rotating clock wheel, photoelectric switch means connected to the valves of said sprinklers, and programmed indexing means comprising a plurality of indexing pins selectively mounted on said clock wheel at spaced intervals and projecting therefrom, said photoelectric switch means comprising a photoelectric cell, a light source spaced from said photo-electric cell and operative to project a light beam across a gap between said cell and said light source whereby said light beam is in line between said cell and said light source, said photoelectric cell being located in the path of travel of said indexing pins as said clock wheel rotates, and said indexing pins being operative to successively traverse said gap to interrupt impingement of said light beam on said cell, whereby said switch means is operative to actuate said sprinkler valves in accordance with the program of said indexing means.

2. A sprinkler control system as defined in claim 1 wherein said clock means is operative to rotate said clock wheel one cycle every twenty-four hours.

3. A sprinkler control system as defined in claim 2 wherein said indexing pins are removably mounted on said clock wheel and depend from the lower surface of said clock wheel, said photoelectric cell being located below said clock wheel and in the path of travel of said pins as said wheel rotates.

4. A sprinkler control system according to claim 3 in which said plurality of indexing pins are arranged in an arcuate row concentric with said clock wheel.

5. A sprinkler control system according to claim 3 in which said plurality of indexing pins comprises at least one group of consecutive pins constituting one pin for each of said sprinklers.

6. A sprinkler control system according to claim 3 wherein said light source is housed in an enclosure having an aperture communicating with said gap, whereby the size of said aperture defines the width of said light beam from said source across said gap.

7. A sprinkler control system according to claim 6 wherein said indexing pin has a transverse thickness dimension greater than said light beam width.

8. A sprinkler control system according to claim 7 wherein said photoelectric switch means includes electrical current level detecting means connected across the output terminals of said photoelectric cell and operative to produce a discrete electrical output signal when the output current from said photoelectric cell reaches a preselected level.

9. A sprinkler control system according to claim 8 wherein said switch means further includes a gate controlled rectifier having its gate electrode connected to the output of said current level detecting means, whereby said gate controlled rectifier is operative to be rendered into a latched conductive mode in response to said discrete electrical output signal from said current level detecting means.