초록 ▼

The present invention relates to a portable adhesive dispensing appliance with adjustable duty cycle. Rather than applying power continuously to the heating element, the element power is intermittently switched over to a variable duty cycle. Savings are gained in three areas: extended life of the el

The present invention relates to a portable adhesive dispensing appliance with adjustable duty cycle. Rather than applying power continuously to the heating element, the element power is intermittently switched over to a variable duty cycle. Savings are gained in three areas: extended life of the element; less heat lost to thermal radiation; and less adhesive waste due to dripping and overheating. The duty cycle may be adjusted manually or automatically based on the temperature of the adhesive in the melt chamber. Additionally, the voltage and/or current to the heating element may be adjusted, either manually or automatically, for more rapid recovery during high usage periods. Higher throughput is achieved by sensing the temperature, comparing the temperature to a desired temperature, and then increasing the duty cycle by either or both one of increasing the frequency of duty pulses and/or lengthening the duration of the duty pulses.

대표청구항 ▼

1. An adhesive dispensing appliance with adjustable duty cycle comprising:a body portion; an adhesive path traversing at least a portion of the body portion; at least one electrical heating element, said at least one electrical heating element for radiating heat to at least a portion of the adhesive

1. An adhesive dispensing appliance with adjustable duty cycle comprising:a body portion; an adhesive path traversing at least a portion of the body portion; at least one electrical heating element, said at least one electrical heating element for radiating heat to at least a portion of the adhesive path; a power source electrically coupled to the at least one electrical heating element, wherein said power source provides power to said at least one electrical heating element; and a pulsing circuit electrically coupled between said power source and said at least one electrical heating element for enabling manual adjustment of the pulse duty cycle applied to said at least one electrical heating element thereby establishing a variable duty cycle enabling stored static heat of said at least one electrical heating element to be expended and replenished periodically with the variable duty cycle. 2. The adhesive dispensing appliance of claim 1, further comprising a switch electrically coupled between said power source and said at least one electrical heating element and operated by the pulsing circuit.3. The adhesive dispensing appliance of claim 1, wherein said pulsing circuit further comprises a circuit for supplying continuous power to said at least one electrical heating element.4. The adhesive dispensing appliance of claim 3, wherein said circuit for supplying continuous power comprises:a sensor for sensing an at least one electrical heating element temperature and generating a corresponding signal; a comparator for comparing a reference signal to said sensed signal and providing a first output; and a power transistor electrically coupled between said power source and said at least one electrical heating element, said power transistor further having a trigger electrically coupled to said comparator, wherein said power transistor provides continuous power to said at least one electrical heating element based on the first output. 5. The adhesive dispensing appliance of claim 4, wherein said pulsing circuit further comprises:a pulse generating circuit electrically connected to said trigger of said power transistor for providing output pulses to said trigger of said power transistor at one of a plurality of on/off rates for providing modulated power to said at least one electrical heating element based on the output pulses. 6. The adhesive dispensing appliance of claim 5 further comprising a manual control coupled to said pulse generating circuit for selecting one of the plurality of desired on/off rates for providing power to said at least one electrical heating element.7. The adhesive dispensing appliance of claim 6 further comprising:a voltage step-up circuit coupled between said power transistor and said at least one electrical heating element and coupled to said pulse generating circuit in parallel with said power transistor for receiving said on/off rate, said voltage step-up circuit providing a voltage step-up to said at least one electrical heating element synchronously with said trigger of said power transistor receiving pulses at said on/off rate. 8. The adhesive dispensing appliance of claim 5, wherein said pulser circuit further comprises:an oscillator circuit for generating sequential pulses; a circuit for receiving said sequential pulses, said circuit comprising a plurality of serial stages, each of the plurality of serial stages generating an output pulse in response to receiving a particular pulse in said sequential pulses; a plurality of multiple position switches, each of the plurality of multiple position switches electrically coupled between one of said plurality of serial stages and said trigger of said power transistor; and means for positioning at least some of said plurality of multiple position switches for passing at least one of said output pulses from one of the plurality of serial stages to said trigger of said power transistor at said on/off rate. 9. The adhesive dispensing appliance of claim 8 further comprises:means for manually selecting an element temperature; and an integrated circuit controller having a memory and a table stored in said memory indicating heating element temperature versus pulse rate, said integrated circuit controller coupled to said means for manually selecting and coupled between said heating element heat sensor and said trigger of said power transistor for receiving the selected element temperature from said means for manually selecting and receiving the corresponding signal from said heating element heat sensor, and in response to the selected element temperature, the corresponding signal and indications from said table stored in the memory of the integrated circuit controller generating a control signal for controlling said on/off rate to said trigger of said power transistor. 10. The adhesive dispensing appliance of claim 9, wherein said control signal for controlling said pulse rate forming said means for positioning at least some of said plurality of multiple position switches for designating a pulse rate.11. The adhesive dispensing appliance of claim 5 further comprises:means for manually selecting an element temperature; and an integrated circuit controller having a memory and a table stored in said memory indicating at least one electrical heating element temperature versus pulse rate, said integrated circuit controller coupled to said means for manually selecting and further coupled between said at least one electrical heating element heat sensor and said trigger of said power transistor for receiving the selected element temperature from said means for manually selecting and receiving the corresponding signal from said at least one electrical heating element heat sensor and in response to the selected element temperature, the corresponding signal and indications from said table stored in the memory of the integrated circuit controller, generating a control signal for controlling said on/off rate to said trigger of said power transistor. 12. The adhesive dispensing appliance of claim 1, wherein said pulsing circuit further comprises:a power transistor having an input electrically coupled to said power source, and output electrically coupled to said at least one electrical heating element and a trigger; and a pulse generating circuit electrically connected to said trigger of said power transistor for providing variable duty cycle output pulses to said trigger of said power transistor at one of a plurality of on/off rates for providing adjustable power to said at least one electrical heating element based on the output pulses. 13. The adhesive dispensing appliance of claim 12 further comprising a manual control coupled to said pulse generating circuit for selecting one of the plurality of desired on/off rates for providing power to said at least one electrical heating element.14. The adhesive dispensing appliance of claim 12, wherein said pulser circuit further comprises:an oscillator circuit for generating sequential pulses; a circuit for receiving said sequential pulses, said circuit comprising a plurality of serial stages, each of the plurality of serial stages generating an output pulse in response to receiving a particular pulse in said sequential pulses; a plurality of multiple position switches, each of the plurality of multiple position switches electrically coupled between one of said plurality of serial stages and said trigger of said power transistor; and means for positioning at least some of said plurality of multiple position switches for passing at least one of said output pulses from one of the plurality of serial stages to said trigger of said power transistor at said on/off rate. 15. The adhesive dispensing appliance of claim 14 further comprises:a sensor for sensing a heating element temperature and generating a corresponding signal; means for manually selecting an element temperature; and an integrated circuit controller having a memory and a table stored in said memory indicating heating element temperature versus pulse rate, said integrated circuit controller coupled to said means for manually selecting and coupled between said heating element heat sensor and said trigger of said power transistor for receiving the selected element temperature from said means for manually selecting and receiving the corresponding signal from said heating element heat sensor, and in response to the selected element temperature, the corresponding signal and indications from said table stored in the memory of the integrated circuit controller generating a control signal for controlling said on/off rate to said trigger of said power transistor. 16. The adhesive dispensing appliance of claim 15, wherein said control signal for controlling said pulse rate forming said means for positioning at least some of said plurality of multiple position switches for designating a pulse rate.17. The adhesive dispensing appliance of claim 12 further comprises:a sensor for sensing a heating element temperature and generating a corresponding signal; means for manually selecting an element temperature; and an integrated circuit controller having a memory and a table stored in said memory indicating heating element temperature versus pulse rate, said integrated circuit controller coupled to said means for manually selecting and coupled between said heating element heat sensor and said trigger of said power transistor for receiving the selected element temperature from said means for manually selecting and receiving the corresponding signal from said heating element heat sensor, and in response to the selected element temperature, the corresponding signal and indications from said table stored in the memory of the integrated circuit controller generating a control signal for controlling said on/off rate to said trigger of said power transistor. 18. The adhesive dispensing appliance of claim 6 further comprising:a voltage step-up circuit coupled between said power transistor and said at least one electrical heating element and coupled to said pulse generating circuit in parallel with said power transistor for receiving said on/off rate, said voltage step-up circuit providing a voltage step-up to said at least one electrical heating element synchronously with said trigger of said power transistor receiving pulses at said on/off rate. 19. The adhesive dispensing appliance of claim 1 wherein said power source contains at least one rechargeable battery.20. The adhesive dispensing appliance of claim 19 wherein said battery supplies at least 14 volts to said manual controls.21. The adhesive dispensing appliance of claim 19 further comprises:an AC/DC rectifier circuit forming part of said power source; and said AC/DC rectifier receiving the output of an AC charging circuit for enabling DC voltage to be generated for charging said at least one battery.