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BACKGROUND OF THE INVENTION
U.S. Pat. No. 3,101,418, which issued Aug. 20, 1963, and which is assigned
to the present assignee, discloses an electric programming unit which is
intended to control electrical equipment, such as the solenoid valves of
an automatic lawn sprinkling system, on a pre-programmed basis. The unit
described in the patent may be set to turn each of a plurality of
different valves of the sprinkling system on and off at predetermined
times each day. The unit described in the patent also includes a
skip-a-day control which is actuated during pre-established 24 hour
periods, so that the controlled equipment may remain inactive throughout
pre-selected days.
The programmed controller of the present invention is of the same general
type as that described in the aforesaid patent, and it may be used for the
same purposes. However, the controller of the invention has certain
advantages over the unit described in the patent, since it is of a simpler
construction. Moreover, the controller of the present invention is more
flexible than the controller of the patent, in that it can be set to
control a relatively large number of different pieces of electrical
equipment, independently of one another, and in that it may be used to
turn as required, and over a relatively large number of days, all on a
pre-programmed basis.
The present invention, like the controller of the patent, finds particular
utility in controlling automatic lawn sprinkler systems, and it serves,
for example, to control the times at which different sections of a
particular lawn sprinkler system are to be turned on and off during each
day, and over, for example, a 28 day interval. However, it will become
evident as the description proceeds that the programmed controller of the
present invention finds general utility in controlling a variety of
electrically energized systems and units, which are to be selectively
controlled so as to be turned on and off at predetermined times, and in
accordance with pre-established programs. For example, the programmed
control unit of the invention may be used to control factory lighting,
traffic lights, electrically controlled machine tools, electrically
actuated doors, and so on.
A feature of the programmed control unit of the invention, in addition to
the flexibility and range of its programmed control functions, is that it
is inherently simple to construct, relatively inexpensive to manufacture,
and in that it may be easily and conveniently installed and programmed for
a wide variety of uses, as set forth above. Another feature of the
programmed control unit of the invention is its capability of providing
long periods of trouble-free operation, and in that it may be easily
serviced, as required.
The particular programmed control unit to be described herein includes two
program storage members which, in the specific embodiment to be described,
take the form of an endless belt and a drum, respectively. The two storage
members are driven at a timed speed by a clock motor which is also
included in the unit. However, other equivalent storage members, such as
magnetic tapes, magnetic discs, or the like, may be used, as will become
evident as the description proceeds.
Each program storage member in the unit to be described, is divided into
separate channels, and a different channel on each storage member is used
to operate on an independent basis, each of the associated pieces of
equipment which are to be controlled by the programmed control unit. The
individual channels may contain, for example, electrically conductive and
non-conductive segments, and each channel may be sensed by a pair of
stylii, with an electrical connection being established across the stylii
of each pair whenever a conductive segment of encountered.
In the particular unit to be described, the endless belt storage member is
divided into hours and minutes on a 24 hour basis. Each channel on the
belt contains conductive and non-conductive segments which establish the
times at which each piece of associated equipment is to be turned on and
off during each day. The drum storage member has the same number of
channels as the belt, and each channel is divided into, for example, two
sections, respectively representing morning and afternoon, for each of 28
days. The channels on the drum also contain electrically conductive and
non-conductive segments, so that the control by the belt may be superseded
by the drum for any day, either in the morning or afternoon, or both.
By virtue of the program storage members discussed, the programmed control
unit of the invention is capable of single or multiple channel control of
associated pieces of electrical equipment, either for a predetermined
program period, or on a repeat cycle mode of operation. The control unit
of the invention provides that the different pieces of controlled
electrical equipment are switched on and off in accordance with
predetermined independent schedules.
The program storage members used in the unit of the invention may take the
form of a magnetic tape, belt, drum, disc, or any other suitable form and
they may be either single channel or multiple channel. Conductive segments
may be formed in the individual channels of the storage members, for
example, by a conductive coating, such as conductive paint or graphite, or
they may be formed by pieces of conductive tape with a pressure-sensitive
adhesive backing. Alternately, the belt may be formed of a conductive
material, and programming may then be accomplished by forming insulated
areas on the conductive material where the electrical output is not
desired. An appropriate adhesive tape, for example, may be used for this
purpose.
Other types of program storage members with appropriate transducers may be
used. These may include, for example, magnetic tapes, drums or discs,
punched tapes, optical recording mediums, and so on. When the aforesaid
conductive segment type of storage members are used, the associated
sensing stylii are connected to electronic trigger gates, for example, so
that low current is maintained through the stylii to minimize arcing, and
the triggered gates provide the relatively high switching currents
required for controlling the associated equipment.
As mentioned above, the control unit of the invention may be used to
control a wide variety of pieces of electrical equipment on a scheduled
basis, independently of one another. The control schedule is extremely
flexible. The unit may be constructed so that the belt, for example, is
easily removable and replaceable, so that control programs may be changed
at will. This latter feature is especially desirable in lawn sprinkling
systems, for example, for summer and winter sprinkling.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of a unit constructed in accordance with one
embodiment of the invention;
FIG. 2 is an end view of the unit of FIG. 1, taken essentially along the
line 2--2 of FIG. 1;
FIG. 3 is a side elevation of the unit of FIG. 1;
FIG. 4 is a fragmentary view of certain operating components of the unit of
the invention, together with a block diagram of the certain associated
electronic controllers;
FIG. 5 is a circuit diagram of the electrical elements included in the unit
of the invention;
FIG. 6 is a fragmentary top plan view, partly in section, of the unit,
showing the manner in which the operating components are driven;
FIG. 7 is a view taken essentially along the line 7--7 of FIG. 6;
FIG. 8 is a sectional representation of the mechanical configuration of one
of the electronic controllers used in the unit, as viewed along the lines
8--8 of FIG. 1; and
FIG. 9 is a fragmentary perspective representation of a portion of the
controller of FIG. 8.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
As best shown in FIGS. 1-3, for example, the unit of the invention includes
an appropriate chassis 10 which supports, for example, a terminal strip
12. The terminal strip is hinged at one end by a hinge 13, and it is
latched at the other end by an appropriate latch 15. This enables the
terminal strip to be turned up and out of the way, to permit access to the
internal operating components of the unit.
A first programmed storage member, in the form of a continuous belt 14, is
supported on the chassis 10. The belt extends around a drum 16, and it is
contained in a storage space within the chassis 10, as best shown in FIG.
2. The belt 14 may have holes at each side, and these holes may be engaged
by protuberances 18 on the drum 16, so as to maintain proper registry
between the belt and the drum.
Also included in the unit is drum 20, both the drums 16 and the drum 20
being supported in appropriate bearings on the end walls of the chassis
10. As best shown in FIG. 2, the drum 16 and drum 20 are supported in
grooves in the end walls of the chassis 10, and are latched in place by
appropriate latches 17. This permits the drums 20 and 16, and the belt 18,
to be removed from the chassis 10, after the terminal strip 12 has been
unlatched and turned up on its hinge 13, so that program changes on the
storage members may be made.
The chassis 10 is supported on an appropriate base 19. A transformer 21 is
mounted on the base, and terminal strips 23 and 25 are also mounted on
appropriate brackets on the base. In addition, a connector 27 is supported
on the base, as is a circuit breaker 29. A rain switch 31 is mounted on
the end of the terminal strip 12 to permit the unit to be de-energized,
for example, on a rainy day, where sprinkling is not needed.
A sensing unit 33 is also mounted on the base, and it serves to activate a
pump in pump operated systems, whenever a valve is energized by the
control unit, so that the pump may be turned off between sprinkling
operations. The drums 20 and 16 are driven by a motor 22. The motor 22,
for example, may be a 24-volt alternate current clock motor. As shown in
FIG. 6, for example, the drive shaft 35 of the clock motor 22 is coupled
to the drum 16 through a spring clutch 37.
When the drive shaft of the clock motor 22 turns in a first direction, the
spring clutch tightens, so that the drum 16 is turned with the motor.
However, the drum may be turned in the opposite direction loosely on the
motor shaft, so that it can be set to any desired angular setting on the
shaft.
As shown in FIG. 7, an indexing pin 16A projects from the end wall of the
drum 16 and engages a lever 41 for each revolution of the drum 16. The
lever 41 is mounted on a standoff 49 on the end wall of the chassis 10. A
pawl 43 is pivotally mounted on the other end of the lever 41 by means of
a rivet 51 and the pawl is spring-biased by a spring 45 into ratchet
engagement with teeth on a gear 47, mounted on the end wall of the drum
20. The action is such that the monthly program drum 20 is turned one
increment for each complete revolution of the daily program drum 16.
Thus, the drum 20 is rotated at one predetermined speed by the clock motor
22, and the drum 16 is rotated at another predetermined speed, to provide
desired movement for the belt 14 and for the drum 20. The drum 20, as
shown in FIG. 4, is termed a "28-day program drum".
The belt 14, as shown in FIG. 4, is divided into a series of adjacent
channels, which extend completely around the belt, and which are
designated 26 in FIG. 4. Conductive segments are disposed along the
various channels 26 to designate the times at which the associated
electrical equipment is to be switched on, during any particular 24-hour
period.
The belt 14 itself may be calibrated along one edge, as shown in FIG. 4, in
hours and minutes on a 24-hour basis, and the calibrations may be suitably
indexed with an indexing symbol on the chassis 10, so that the hours and
minutes designated on the belt correspond to the time of day. It will be
understood that the drive by the clock motor 22 is such that the belt 14
will make one complete revolution for each 24-hour period, in the
particular embodiment under consideration.
The drum 20, on the other hand, is driven at a relatively slow speed, so as
to make a complete revolution, for example, once for every 28-day period.
The drum 20 is divided into half days, as mentioned above. The drum 20
also has peripheral channels 24 adjacent to one another and corresponding
in number to the channels 26 on the belt 14, and corresponding pairs of
channels on the belt and drum are used to control the different
instrumentalities associated with the unit. As described above, the
one-way spring clutch 37 of FIG. 6, permits the drums 16 and 20 to be
preset to any desired angular position, so that the unit may be properly
calibrated with respect to the time of day.
The channels on the belt 14 are sensed, for example, by a pair of stylii
designated 30, and the channels on the drum 20 are sensed, for example, by
a pair of stylii designated 32. Whenever a pair of stylii 30 encounters a
conductive segment in its channel, a connection is established across the
tips, and this also prevails for the corresponding stylii 32. Therefore,
when a pair of stylii 30 encounters a conductive segment, the resulting
electrical connections are used to trigger a switching circuit, and to
switch on an associated piece of equipment. However, the corresponding
stylii 32 are connected in series with the stylii 30, so that in the
morning or afternoon, or both, of any particular day, the stylii 32 may be
made to encounter a non-conductive segment in the corresponding channel,
so that no switching is effectuated in the morning or afternoon, or both,
on that particular day.
The various stylii 30 and 32 are connected in series, as shown in FIG. 4,
and to corresponding electronic controllers designated 50. The controllers
50 are mounted on the top of the unit, as shown in FIG. 1, along the
terminal strip 12, and as many controllers as desired for any particular
installation may be mounted on the terminal strip. It will be appreciated
that when the terminal strip is turned up to permit access to the belt and
drums, the controllers are turned up with the terminal strip 12, and their
corresponding stylii are disengaged from the channels on the drum 20 and
belt 14.
The circuitry of the controllers 50 is connected across the pair of
alternating current buses 52, as is the clock motor 22 (FIG. 5). The buses
carry, for example 24-volt alternating current, derived from the
transformer 21 through the circuit breaker 29. The rain switch 31, as
shown in FIG. 5, must be closed, or else the controllers are de-activated,
although the drum and belt continues to operate. This means that the
program sequence is not lost, even through the equipment is turned off by
the rain switch for any particular period of time.
When any one of the electronic controllers 50 is triggered, it provides a
connection from its corresponding output terminal and one of the two buses
52, so that a relatively high switching current may flow through the
controlled equipment to switch on the particular equipment. It will be
appreciated that the control by each of the individual controllers 50 is
independent of any of the other controllers, so that the associated pieces
of equipment may be independently controlled.
An appropriate trigger gate circuit which may be included in each of the
controllers 50 of FIG. 4 is shown in FIG. 5. A manually controlled switch
60, for each controller, may be set either to "off" or to "auto" or to
"man". The "off" terminal of the switch is open, whereas the "auto"
terminal is connected through the corresponding stylii 30 and 32 to a
solid state switching device, such as triac 61. The manual terminal of the
switch is connected directly to the triac 61, to fire the triac and
actuate the associated equipment, whenever the switch 60 is set to "man".
A resistor 63 is interposed between the armature of switch 60 and the
triac 61. An indicating lamp 65 is included in each controller 50, which
glows to indicate when a particular controller is in its active state.
Therefore, when the switch 60 in any controller 50 is set to "man" the
associated piece of equipment is turned on. However, when the switch 60 in
any controller 50 is set to "auto", the corresponding equipment is turned
on only at predetermined times under the control of the monthly and daily
program units.
The connector 27 permits the entire system to be connected to and
disconnected from the associated equipment, without any need to disturb
the wiring to the equipment itself.
The physical details of the controller 50 are shown in FIGS. 8 and 9. It
will be noted that one stylus 30 and one stylus 32 may be adjusted in a
longitudinal manner with respect to the other stylus of the pair. This is
achieved by loosening and tightening a set screw 70 which extends through
a slot in the associated stylus, such as best shown in FIG. 9. This
permits the stylii of each pair to be offset with respect to one another
slightly to increase the start and stop sensitivity for short time periods
without the need to decrease the length of the associated conductive
segments below the practical limits.
The invention provides, therefore, a relatively simple and compact
programmed control unit, by which a plurality of independent controls may
be exerted on various different pieces of extraneous equipment, and by
which the different controls may be sustained over relatively long time
periods.
It will be appreciated, of course, that the particular embodiment
illustrated and described above, is merely by way of example, and
equivalent components may be used for suitable modifications. Therefore,
although a particular embodiment of the invention has been shown and
described, modifications may be made. It is intended in the claims to
cover the modifications which come within the spirit and scope of the
invention.
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