Abstract:
A self-contained pneumatic switch operating system for operating a conventional toggle switch is disclosed which includes a source of compressed air, a switch positioner including a linear pneumatic operator connected to the source of compressed air and to a pair of spaced switch operating members for operating a toggle switch situated therebetween. A housing for containing components of the switch operating system including a base member adapted to replace a conventional wall switch plate and a controller for controlling the operation of the switch positioner and a self-contained power supply for operating the switch positioner and the controller are also provided.

Description:
BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to electrical switch operation, particularly timed auxiliary wall switch operators and, more particularly, to a self-contained programmable wall switch operating system for use with an existing conventional wall switch having a toggle operator. The system accomplishes automatic time-variable switch positioning with a compact low cost pneumatic system which also requires very little power to operate. 
     II. Related Art 
     The related art includes a variety of devices designed to actuate standard wall mounted, toggle operated light switches. One such device, shown and described in U.S. Pat. No. 3,985,982, features battery operated embodiments designed to fit over a conventional switch wall plate (FIGS. 3,  5  and  6 ) and features a solenoid-operated push/pull rod with manual override and an electrical or wind-up timer control. Examples of other such devices can be found in U.S. Pat. Nos. 4,002,925, 4,645,942, 5,306,957, 5,397,869 and 5,719,362. While these devices will operate a standard wall switch automatically, semi-automatically or replace a standard wall switch with an automatically operating device, they are all rather complicated with many designs requiring gears, linkages, springs and other moving parts which generally need to be made to close tolerances which, in turn, results in high parts cost and extensive labor to assemble. This is generally not the only drawback as these devices also require more than a practical amount of power to operate. Therefore, because of shortened battery life, they do not lend themselves to practical self-contained battery-operated retrofit designs. 
     The need for a low-cost, low power retrofit device to operate a conventional wall switch automatically on a time-variable positioning basis is unquestioned. Present systems which, for example, turn lights on and off at various times of the day to simulate occupancy for vacationing home owners, or the like, are expensive devices which must be plugged in between the appliance and the power source. Since most new homes are built with wall switches to control a variety of lights, the desirability of a low cost means available to automatically control one or more switches to accommodate vacationing homeowners and to turn on lights for those returning from a day at work would be very desirable. Furthermore, a self-contained device which requires only the removal of the two screws holding the switch plate, the lifting off of the existing cover and the installation of the device in position and refastening of the screws enables any homeowner to install an automatic switch operator without any special skills. It would also be very desirable for such a device to accomplish a very large number of operations on a single set of integral batteries. 
     Accordingly, it is a primary object of the present invention to provide a device for automatically operating a conventional wall switch on a timed basis. 
     It is a further object of the present invention to provide a device for automatically operating a conventional wall switch that is small and self contained and uses a minimum number of moving parts. 
     A still further object of the present invention is to provide a device for automatically operating a conventional wall switch that is relatively inexpensive to buy and requires very little power to operate. 
     Another object of the present invention is to provide such a device that is compact and requires little additional space. 
     Yet another object of the present invention is to provide such as device which can be installed on an existing switch without electrical connection by one unskilled in the electrical arts. 
     These and other objects and advantages of the present invention will become clear to those skilled in the art upon familiarization with the further descriptions contained herein, together with the appended drawings. 
     SUMMARY OF THE INVENTION 
     By means of the present invention, problems and drawbacks associated with prior automated add-on electrical wall toggle switch operating devices are solved by the provision of a low-cost, reliable automated switch operator that also features low power consumption so that a single set of batteries can last for hundreds of cycles. It is the combination of low cost, reduced complexity and operating power requirement that make the switch operating system of the present invention more practical than previous devices of the class. 
     The system of the present invention is a self-contained unit that carries its own low voltage power supply and housing including a bottom plate that carries system components and is designed to mount in lieu of or over a conventional switch plate or box cover using the same or a similar pair of attaching screws. Installation is easily accomplished by even an unskilled homeowner as no electrical connections are involved. 
     The switch operating system of the present invention features pneumatic operation and includes a pneumatic operator which utilizes a solenoid-controlled miniature air pump and cylinder which, in turn, operates a ram. The ram is linked both to the wall switch toggle and a mechanical spring-biased catch and repel mechanism which may be a magnetic touch latch device such that when the air cylinder extends, the toggle is operated to one position, for example the “ON” position and the latch spring is compressed in a latching mode. A solenoid is provided which closes and allows pressurization of the air cylinder when it is energized and vents the system when de-energized. The air cylinder and associated ram are caused to remain extended by the latch in its latching mode until the switch position is reversed even though air pressure is lost when the solenoid is de-energized. Upon a second pushing of the latch by the ram, the spring-loaded latch is put in a release or repel mode and the compressed latch spring is released which causes the ram to retract to its original starting position thereby reversing the position of the switch. 
     In this manner, electric power is necessary to “flip the switch” only in one direction and only a slight extension of the cylinder is required to activate the reversal of the latch. The unit further includes integral batteries, a programmable key pad and an LCD display so that the operation of the switch can be programmed in the manner of a night setback thermostat, or the like, the setting overridden or the device shut off, if desired. 
     It will be appreciated that the linear operating air cylinder and catch and repel mechanism or touch latch are the only moving parts in the system and they should operate reliably over thousands of cycles. Components of the system are all miniaturized and readily available commercially with the only modification necessary being the attachment of toggle-operating elements to the ram operated by the air cylinder. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings wherein like numerals designate like parts throughout the same: 
     FIG. 1 is a perspective view of a conventional wall switch with flush-mounted plate; 
     FIG. 2 is a perspective view of a self-contained, programmable wall switch operating system and according with the present invention with a transparent housing showing placement of the internal parts; 
     FIG. 3 is an exploded perspective view depicting the main elements of the pneumatic switch positioner of the invention; 
     FIGS. 4 and 5 depict the pneumatic switch positioner of the invention as mounted with the upper portion of the housing missing and assembled with pneumatic connectors in the “ON” and “OFF” position, respectively; and 
     FIG. 6 depicts a side elevational view partially in sections showing the programmable wall switch operating system mounted on a conventional switch box. 
    
    
     DETAILED DESCRIPTION 
     A detailed description will now be presented with reference to the several drawing figures. The embodiments shown and described are meant to illustrate the low-cost automated switch operating system of the invention and are presented by way of example and not limitation and it will be recognized by those skilled in the art that certain of the components can be replaced by other low-cost equivalents which also preserve the nature of the low power required to operate the system. 
     With this in mind, FIG. 1 depicts a familiar and highly conventional light switch and face plate, generally at  10 , including a face plate or box cover  12  secured by screws  14  and  16  which hold the face plate to a switch box mounted in the wall as is well known in the art. The conventional, manually operated toggle is shown protruding through an opening in the plate  12  at  18 . 
     In FIG. 3, the basic components of the toggle operating system of the automated electrical wall toggle switch operating device of the invention are shown in exploded relation. These include a micro-air pump  20  which may be a conventional micro-air pump such as those manufactured by Sensidyne, Inc. or other micro-size pump of the class. These devices are well known and are engineered to provide the performance of a larger pump on a miniature scale with low power consumption. An output connection is shown at  22 . The system further includes an air cylinder  24  compatible with the air pump  20  and containing a bore  26  and O-ring  27  which seals a hollow ram device  28  which carries a pair of spaced shaped toggle operating members at  30  and  32 . 
     Aligned with the ram  28  and cylinder  24  is a catch and repel mechanism  34  attached to the ram. It is preferably in the form of a single magnetic touch latch which may be of a type familiar to those in the cabinetry arts for catching and latching a cabinet door on a first push and automatically repelling (opening) the cabinet door upon a second push to an open position. Such devices are available commercially as from EPCO Company in Flint, Mich. An initial push on the associated piston  36  of the touch latch  34  causes the piston to retract and for the latch to assume and hold the latched or retracted position. A second pushing on the latch through piston  36  causes the latch to release and the spring to propel the piston  36  to an extended position thereby opening the latch. Thus, the cylinder  24  is required to operate the ram only in the extending direction and the touch switch operates the system in the reverse direction. 
     The system controls include an operating solenoid pictured at  38 . Air connections  40  and  42  are shown on the solenoid and air cylinder respectively. Four conventional dry cells for powering the system are shown at  44  which provide the power for operating the toggle automated system of the invention. The solenoid  38  may also be a conventional commercially available TDS-V05B type electro-magnetic valve of a type widely used as fast exhaust valves on electronic medical devices. 
     FIGS. 4 and 5 show the magnetic switch positioner of FIG. 3 assembled and a captured toggle in the “ON” and “OFF” positions, respectively. The components are shown mounted on a base or mounting plate  50  which is designed to be of a size to replace the plate  10  of FIG. 1 with the openings  52  and  54  based so as to be attachable again by screws as at  14  and  16  in FIG.  1 . FIGS. 4 and 5 also include air or pneumatic lines  56 ,  58  and  60  with common T  62  interconnecting the pump  20 , cylinder  24  and exhaust solenoid  38 . A toggle is shown at  64 . In FIG. 4, the toggle is shown in the “UP” or “ON” position with the cylinder  24  and hollow ram  28  fully extended and the touch latch  34  with piston  36  retracted. The toggle switch  64  is forced into the upward position by the shaped member  30  attached to the hollow ram  28 . 
     In FIG. 5, the touch latch  34  is shown with piston  36  extended and the cylinder  24  with hollow ram  28  fully retracted. In this manner, member  32  operates to push the toggle  64  into the “DOWN” or “OFF” position. FIG. 2 shows the entire assembly with a housing cover  70  and including a conventional key pad for data entry in programming the device at  72  and an LCD display is shown at  74 . The key pad and LCD output device are wired in conventional fashion through a micro-chip which can be used to program the operation of the solenoid and the pump to position the switch on demand as desired. The details of these are considered highly developed in many arts and can readily be implemented as necessary in manufacturing the device of the present invention. 
     FIG. 6 depicts the automated switch operating system of the invention mounted on a conventional switch box  80  by a pair of screws  82  and  84 . The bottom mounting plate  50  has replaced the switch plate  12  of FIG. 1 on a conventional switch box. 
     It can be seen from the above that the unit of the present invention simply operates on air pressure which eliminates many mechanical linkages associated with prior art devices. Only the spring loaded latch piston  36  and the ram  28  are required to move. 
     In operation, when the timer activates the device calling for the switch to be turned on, the solenoid  38  closes and the micro-pump  20  is turned on by a conventional relay in the circuitry to provide air pressure which is directed via tubes  56  and  58  into the blind end of air cylinder  24 . This causes the ram to extend forcing the piston  36  and the touch latch  34  to retract and the member  30  to operate the toggle  64  into the “ON” position. When the ram  28  reaches the end of its travel, the light will be in the “ON” position and the spring catch of the touch latch will be fully compressed which, in turn, locks the latch and the ram in this position. Thus, when the air pressure is lost, as the solenoid is de-energized while the switch is on, the touch latch will maintain the system in a status quo position. Upon a signal to turn the switch to the “OFF” position, the solenoid  38  again signals the pump to turn on momentarily so that the ram again pushes on the touch latch. This causes the touch latch to change to the release/repel mode releasing the catch spring and causing the piston  36  to extend. At the same time, the solenoid  36  is switched to the vent position allowing the air in the cylinder  34  to escape through line  60  being vented out of the solenoid. In this manner, the spring catch provides the energy to shut off the switch as the ram retracts and the member  32  pushes the switch into the “OFF” position as shown in FIG. 5 with the spring catch of the touch latch unlocked. 
     This invention has been described herein in considerable detail in order to comply with the Patent Statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use embodiments of the example as required. However, it is to be understood that the invention can be carried out by specifically different devices and that various modifications can be accomplished without departing from the scope of the invention itself.