Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
  • D06F75/00—Hand irons
  • D06F75/08—Hand irons internally heated by electricity
  • D06F75/26—Temperature control or indicating arrangements
• • G—PHYSICS
  • G04—HOROLOGY
  • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
  • G04C3/00—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means
  • G04C3/001—Electromechanical switches for setting or display
  • G04C3/002—Position, e.g. inclination dependent switches
• • G—PHYSICS
  • G04—HOROLOGY
  • G04F—TIME-INTERVAL MEASURING
  • G04F1/00—Apparatus which can be set and started to measure-off predetermined or adjustably-fixed time intervals without driving mechanisms, e.g. egg timers
  • G04F1/005—Apparatus which can be set and started to measure-off predetermined or adjustably-fixed time intervals without driving mechanisms, e.g. egg timers using electronic timing, e.g. counting means

Definitions

• This invention relates to electrical appliances of the type which use a heater element and in particular to a structure which automatically shuts off the device in response to non-use.
• This invention solves the above-mentioned problems by detecting the last use of an energized appliance and shutting off the appliance after a given time has- elapsed from this last use without further use.
• An audible and/or visual indication is provided to alert the user that the appliance has been turned off as a result of non-use over the selected time interval.
• another audible or visual indication is activated prior to the actual power removal from the appliance to warn the user that the appliance will be turned off unless used.
• Figure 1 is a schematic diagram of one embodiment of the invention using a timer formed either as a separate element or as an integral part of the appliance.
• Figure 2 shows the invention embodied as a separate timer accessory used with a clothes iron.
• Figure 3 shows the invention embodied as an integral part of a clothes iron.
• Figure 4 shows the invention embodied as a separate timer accessory.
• FIG. 1 Shown in Figure 1 is a schematic of one timing circuit constructed in accordance with this invention. Those skilled in the arts will recognize that other circuits can also be constructed in accordance with this invention and thus this description is illustrative only and not limiting.
• the circuit of Figure 1 establishes a time interval during which the controlled appliance must be used and this use sensed. If the timer circuit fails to detect use in this interval, it shuts off the power to the appliance.
• the appliance use-detector and timer (UDT) is implemented in either of two basic forms. The. UDT can be separate from the appliance to be controlled or it can be incorporated into the appliance at the time of manufac ⁇ ture. Thus, while in Figure 1 the main portion of the UDT circuit 1 is separate from the appliance 49 to be con ⁇ trolled, with two minor changes described below, circuit 1 can be formed as an integral part of appliance 49.
• A.C. input voltage is supplied to both the UDT 1 and the appliance 49 from the input lines 46 and 47.
• Triac 45 is supplied to both the UDT 1 and the appliance 49 from the input lines 46 and 47.
• E ⁇ AZT- is a gate-controlled thyristor which, in its conducting state, allows the input line voltage, minus a small voltage drop, V j . to be applied to the appliance 49 at lines 57 and 58.
• V j a small voltage drop
• Master oscillator 12 (of a well-known design) produces an output waveform 13 with a frequency of approximately one-half hertz which is used to clock counter "A” 15, counter “B” 9, and counter “C” 37, and to modulate the visual indicator 54 and audio oscillator 27.
• Counter “A” 15 is the primary delay timer and establishes the period during which appliance activity must be detected to prevent a power shutdown sequence from being initiated.
• Counter “B” 9 provides an intermediate delay which is less than the shortest delay of counter "A” 15 if no current through load 53 is sensed within the given delay of counter ** B" 9. The use of counter 9 is only necessary when the UDT 1 is separate from (i.e., not part of) the controlled appliance 49.
• Resistors 29 and 30 act as a voltage divider which, in the absence of sufficient input voltage to the ( ⁇ ) terminal of amplifier 28, causes the output of amplifier 28 to drop to a near zero volt level. This low voltage level acts as a logic "0" input to OR gate 7 and NAND gate 18. When there is current through the appliance 49 circuit, V , will cause the output of amplifier 28 to become positive, thus producing a logic "1" level to gates 7 and 18.
• This pulse acts as a power-up reset for counter "A" 15 via OR gates 6 and 10; for counter “B” 9 via OR gates 6 and 7; for counter “C” 37 via OR gate 6; for bistable latch circuit comprised of NAND gates 19 and 21 via OR gate 6 and inverter 20; and finally for the bistable latch circuit comprised of NOR gates 39 and 40 via OR gate 6.
• the three counters 15, 9 and 37 are reset to zero causing each counter output to be at a "O" logic level.
• the output signal from NAND gate 19 will be at logic “0” holding the output of NAND gate 22 at logic "1" and, in turn, the output of inverter 23 at logic "0".
• This low level signal from inverter 23 allows current to flow from V+ through light-emitting diode (LED) 54 and resistor 24. In response to this current LED 54 will glow constantly to indicate that power is applied to the UDT circuitry.
• LED light-emitting diode
• the "0" level at the output of inverter 23 will also hold the output of NAND gate 26 at logic 1, which inhibits the audio oscillator•27 thereby preventing transducer 55 from producing sound.
• the power-up reset pulse causes the output of NOR gate 40 to go to a logic "0" level and, along with the "0" output from counter ⁇ * C" 37, produces a "O" level signal at the output lead of inverter 41.
• the output lead from inverter 41 is connected to a light emitting diode in optical coupler 43.
• the LED of the optical coupler integrated circuit 43 will normally produce light due to the current from V+ through resistor 42.
• Optical coupler 43 is a device such as MOC 3011 made by Motorola, which, when the LED is on, produces light which impinges on the light sensitive gate of an internal triac, causing the triac to conduct. In this way as the voltage V . increases sinusoidally, the value of V . will produce gate current through resistor 56, the triac of coupler 43, and the gate 44 of triac 45. When this gate current reaches a value sufficient to trigger the thyristor action of triac 45 the device will latch in a conducting mode for the remainder of each A.C. half-cycle.
• coupler 43 can be replaced by any one of a number of different structures, such as an electro-mechanical reed relay, or a circuit for pulsing the gate of triac 45 so as to control the conductive state of this triac in response to the state of bistable circuit comprising gates 39 and 40.
• counter "A" 15 will begin counting input waveform 13 transitions which are applied via NOR gate 14.
• the time delay switch 16 allows manual selection of an appropriate time* interval during which the appliance 49 must be used. Assume for the present that switch 16 is in the position shown, namely a fifteen minute delay. A logic "0" signal will exist at the junction of the wiper arm of switch 16 and resistor 17. This "0" level signal will hold the output of NAND gate 18 at a logic "1".
• Use-detector 2 can consist of various means of detecting that the appliance 49 has been used either by sensing either motion of the appliance 49 or sensing the grasping or handling of the appliance 49 by the user. " The actual implementation of the use-detector 2 will be more clearly understood during the discussion of Figures 2, 3 and 4. For the present it should suffice to indicate that each time appliance 49 is used, waveform 8 will be positive, thereby resetting- all the counters 15, 9 and 37 and
• Use detector 2 (such as a switch in the handle of appliance 49 or an accelerometer) is such that when appliance 49 is no longer being used, waveform 8 will once again return to zero, which releases counters "A" 15 and "B" 9 to proceed from a zero count.
• Counter "C” 37 will count the clock transitions from the output lead of inverter 23 for a period of, say, fifteen seconds to .allow the user time to activate the use-detector 2 in order to prevent a shutdown of power to appliance 49. If no such use-detection is established within the prescribed fifteen seconds the output signal from counter "C" 37 will become positive as indicated by waveform 38. This positive level of waveform 38 will latch the bistable circuit comprised of NOR gates 39 and 40 to a logic "0" at the output of gate 39.
• This logic "0" level signal performs several tasks, namely, it holds the output signal of NAND gate 19 high via input 19b; it inhibits the audio oscillator via the input lead to NAND gate 26.; and it causes the output signal of inverter 41 to go to a logic "1" level which turns o f the optical coupler 43. Turning o f optical coupler 43 removes the gate 44 drive current for triac 45 thus shutting off power to the appliance 49. It should be noted that once the latch circuit of NOR gates 39 and 40 removes power to triac ' 45, and therefore appliance 49, power may be restored by activating the use-detector 2 or momentarily unplugging the UDT 1, thus temporarily removing power input at lines 46 and 47.
• FIG. 2 is a pictorial representation of a use- detector and timer used as an accessory for a clothes iron.
• the previously described UDT 1 and its associated circuitry are enclosed in housing 64.
• Power is supplied to the UDT system by inserting plug 78 into a standard wall receptacle 79.
• Power is supplied to the clothes iron 71 by inserting plug 76 into the receptacle 75.
• Cord 72 is retained in clamp 60 so that movement of the clothes iron 71 across the ironing board surface 70 will cause cord 72 to move, and this motion will be transmitted through rod 62, and spring coupling 77 to the mounting base 63.
• Motion of mounting base 63 will, in turn, be detected by the use-detector 2 which was described in the previous text. The actual physical coupling between mounting base 63 and use-detector 2 will become apparent later during the discussion of Figure 4.
• Figure 3 is a pictorial representation of the use- detector and timer housed as an integral part of a clothes iron 71.
• the use-detector 2 in this configuration is shown as a switch 2 which is activated each time the clothes iron 71 is grasped by the user.
• FIG. 4 is a cross-sectional view of the UDT 1 to be used as an accessory to an appliance.
• Power enters the housing 64 via power cord 73 which contains wires 46 and 47.
• the components comprising much of the system are mounted on a printed circuit board 74.
• Triac 45 is mounted to heat sink 61.
• Power to the appliance to be controlled exits the housing 64 via wires 57 and 58 which are attached to receptacle 75.
• Plug 76 and cord 72 are part of the appliance to be controlled.
• Clamp 60 retains cord 72 in such a manner that any move ⁇ ment of the appliance and, hence, the cord'72 will cause movement of rod 62, spring coupling 77 and mounting base 63.
• Use detector 2 consists of a piezoelectric device (of a well-known design) similar to a ceramic phono cartridge which is coupled to mounting base 63 via contact arm 59. In this way small movement of the mounting base 63 will cause use-detector 2. to produce a voltage output suffi ⁇ cient to perform the reset functions previously described. Although a piezoelectric device was used to detect move ⁇ ment of cord 72, and thus the use of the appliance, it should be recognized that similar devices such as strain gauges, accelero eters and photo-electric or magnetic sensors could be substituted.
• the basic timing functions can be provided using analog timing circuits or even bimetal, thermal-delay switches.
• the timing and logic can be performed by a microprocessor-based system which also can control the appliance temperature, etc.
• Master oscillator 12 can be replaced by a crystal-controlled oscillator or a line frequency counter.
• the triac 45 which is used as a power control device, one can substitute an electro-mechanical relay along with a current sensing means such, as a current transformer or Hall-effect device, if required.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Keying Circuit Devices (AREA)
• Measurement Of Unknown Time Intervals (AREA)

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• 1982
  • 1982-03-31 WO PCT/US1982/000416 patent/WO1982003520A1/en unknown
  • 1982-03-31 EP EP19820901468 patent/EP0076312A1/de not_active Withdrawn

Non-Patent Citations (1)

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