Patent Publication Number: US-2010116441-A1

Title: Portable heat sealing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part patent application of U.S. application Ser. No. 12/269,252 filed on Nov. 12, 2008, the entire contents of which are hereby incorporated by reference for which priority is claimed under 35 U.S.C. § 120. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a portable heat sealing apparatus such as a heat sealing apparatus used in a kitchen to close and seal bags of thermoplastic material. 
     BACKGROUND OF THE INVENTION 
     Generally, two major types of sealing machine exist. One is a stationary sealing machine, and the other is a portable sealing machine. Both types have advantages and disadvantages. Stationary sealing machines are used most often for large packages and provide better sealing performance but consume lots of electrically. Portable sealing machines are used most often as kitchen appliances to seal smaller packages and consume less power. However, sealing machines with the advantages of both types are not available in the market. Therefore, people either have to buy both or accept the inherent disadvantages of the one they purchase. 
     Because conventional portable sealing machines are small and have a small heat sealing region of 1˜2 centimeters, they are easy for people to grip and squeeze. However, sealing a large plastic bag smoothly and efficiently requires that a person operating the machine apply a consistent pressure and slide the plastic bag continuously and smoothly along the heating region, which can be challenging. Using sealing machines with a longer heat sealing region with a longer heating module results in the longer heating module stretching and becoming slack. 
     Conventional sealing machines generally comprise a base, a power module, a cover, a heating module and optional over-current protection. When the cover is pressed toward the base, power is provided to the heating module, and the heating module generates heat to seal a plastic bag. The over-current protection is provided in a circuit that will deactivate the heating module to prevent the sealing machine from overheating and damaging the sealing machine. However, it only protects the sealing machine itself but not a person operating the sealing machine. For example, if a child plays with the sealing machine and does not notice or understand that the heating module is activated, she or he may be burned. 
     SUMMARY OF THE INVENTION 
     The objective of the present invention is to provide a portable heat sealing apparatus with a longer heating element that is kept taut so bonded seals are smooth and continuous and can be used to effectively and efficiently close and seal large plastic bags. 
     The portable heat sealing apparatus in accordance with the present invention comprises a body, a heating module, an upper case and a power module. The heating module has an elongated heating element held taut by two elastic elements to ensure a smooth, continuous bond between facing surfaces of a plastic bag. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         FIG. 1  is a perspective view of a portable heat sealing apparatus in accordance with the present invention; 
         FIG. 2  is an exploded, bottom-rear perspective view of the portable heat sealing apparatus in  FIG. 1 ; 
         FIG. 3  is an exploded, bottom-rear perspective view of an upper case of the portable heat sealing apparatus in  FIG. 1 ; 
         FIG. 4   a  is an exploded perspective view of a base and cover of the portable heat sealing apparatus in  FIG. 1 ; 
         FIG. 4   b  is an enlarged perspective view of one end of a heating module mounted in the base of the portable heat sealing apparatus in  FIG. 4   a;    
         FIG. 5  is an exploded perspective view of a heating module of the portable heat sealing apparatus in  FIG. 4   a;    
         FIG. 6  is a top-front perspective view of the base of the portable heat sealing apparatus in  FIG. 4   a;    
         FIG. 7   a  is a circuit diagram of a driving circuit of the portable heat sealing apparatus in  FIG. 1  using a DC power source; 
         FIG. 7   b  is a circuit diagram of a driving circuit of the portable heat sealing apparatus in  FIG. 1  using an AC power source; 
         FIG. 8  is an exploded, bottom-rear perspective view of the portable heat sealing apparatus in  FIG. 1  with a hanger assembly comprising a hanger panel and two wall connectors; 
         FIG. 9  is an exploded, bottom-rear perspective view of the portable heat sealing apparatus in  FIG. 1  with a hanger assembly comprising multiple suction cups. 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION 
     With reference to  FIGS. 1 ,  2 ,  8  and  9 , a portable heat sealing apparatus in accordance with the present invention closes and seals plastic bags quickly and efficiently and comprises a body ( 1 ), a heating module ( 2 ), an upper case ( 3 ), a power module ( 4 ) and an optional hanger assembly ( 5 ). 
     With further reference to  FIGS. 4   a  and  4   b , the body ( 1 ) comprises a base ( 10 ) and an optional cover ( 11 ). 
     The base ( 10 ) has two ends, a rear wall, a front wall, an outer surface, an open top and a bottom surface and comprises two optional hinge slots ( 13 ), a heating module compartment ( 16 ), a battery compartment ( 15 ) and multiple optional transverse mounting slots ( 19 ), at least one optional hanging lip ( 18 ) or both. 
     The rear wall has an optional electrical cord hole. 
     With further reference to  FIG. 6 , the hinge slots ( 13 ) are formed respectively on the ends of the base ( 10 ) and communicate with the rear wall, and each hinge slot ( 13 ) has an inner wall ( 131 ) and a mounting hole ( 132 ). The inner wall ( 131 ) is parallel to the end wall. The mounting hole ( 132 ) is formed through the inner wall ( 131 ) and aligns with the mounting hole ( 132 ) in the inner wall ( 131 ) of the other hinge slot ( 13 ). 
     The heating module compartment ( 16 ) is formed in the base ( 10 ) between the ends and may be adjacent to the front wall. 
     The battery compartment ( 15 ) is formed inside the base ( 10 ), may be formed against the rear wall and has at least two contacts ( 151 ), a battery access hole ( 152 ) and a battery access panel ( 153 ). The battery access hole ( 152 ) is formed through the bottom surface of the base ( 10 ) and communicates with the battery compartment ( 15 ). The battery access panel ( 153 ) is removably mounted in and closes the battery access hole ( 152 ). 
     The multiple transverse mounting slots ( 19 ) are eccentric holes formed through the bottom surface of the base ( 10 ). 
     The at least one hanging lip ( 18 ) is formed on and protrudes from the bottom surface of the base ( 10 ). 
     The cover ( 11 ) is mounted on and closes the open top of the base ( 10 ) and has a front edge, two rear corners, a heating slot ( 111 ), two optional hinge notches ( 113 ) and an optional activation hole ( 112 ). 
     The heating slot ( 111 ) is formed through the cover ( 11 ), may be near the front edge and corresponds to the heating module compartment ( 16 ) in the base ( 10 ). 
     The hinge notches ( 113 ) are formed respectively in the rear corners and correspond respectively to the hinge slots ( 13 ) in the base ( 10 ). 
     The activation hole ( 112 ) is formed through the cover ( 11 ) near one end. 
     With further reference to  FIG. 5 , the heating module ( 2 ) is mounted longitudinally in the base ( 10 ), protrudes through the heating slot ( 111 ) in the cover ( 11 ) and comprises an adiabatic stand ( 22 ), an adiabatic pad ( 23 ), a heating element ( 24 ), two isolation devices ( 25 ), two elastic elements ( 26 ) and an adiabatic sheet ( 21 ). 
     The adiabatic stand ( 22 ) has a longitudinal ridge ( 221 ). 
     The adiabatic pad ( 23 ) is mounted longitudinally on the longitudinal ridge ( 221 ) of the adiabatic stand ( 22 ); 
     The heating element ( 24 ) generates heat when current passes through it, is mounted longitudinally on the adiabatic pad ( 23 ), is at least 10 cm in length, has two ends, may be a resistance wire of a metal alloy of 70% Fe, 25% Cr and 5% Al, is always held under tension ranging from 500 gm when cold to 300 gm when hot and has two electrical connectors ( 27 ). The electrical connectors ( 27 ) are mounted respectively on the ends of the heating element and may be brass rings mounted respectively around ends of the heating element ( 24 ). 
     The isolation devices ( 25 ) are connected respectively to the ends of the heating element ( 24 ), are thermal and electrical insulators and may be ceramic rings. 
     The elastic elements ( 26 ) are connected respectively to the ends of the base ( 10 ) and respectively to the isolation devices ( 25 ) to hold the heating element ( 24 ) taut and securely on the adiabatic pad ( 23 ) and in the base ( 10 ). 
     The adiabatic sheet ( 21 ) covers the heating element ( 24 ) and the adiabatic pad ( 23 ) so the heating element ( 24 ) will not burn a hole in a plastic bag being sealed by the heat sealing apparatus. 
     With further reference to  FIG. 3 . the upper case ( 3 ) is connected pivotally to and covers the base ( 10 ), presses a plastic bag against the adiabatic sheet ( 21 ) so the heating element ( 24 ) can heat and seal the plastic bag, has an inner surface, two ends, a rear edge and a front edge and comprises an optional activation rod ( 31 ), a mounting slot ( 32 ), a press ( 33 ) and two optional hinges ( 34 ). 
     The activation rod ( 31 ) is formed on and protrudes down from the upper case ( 3 ) and corresponds to and presses through the activation hole ( 112 ) when the upper case ( 3 ) is pressed against the base ( 10 ). 
     The mounting slot ( 32 ) is formed parallel to the front edge of the upper case ( 3 ) and corresponds to the heating module ( 2 ). 
     The press ( 33 ) comprises a contact pad ( 332 ) and a mounting frame ( 331 ). 
     The contact pad ( 332 ) is a strip of resilient material, is mounted securely in the mounting slot ( 32 ) and has two exposed surfaces. The exposed surfaces comprise a recessed outer surface and a protruding central surface. The recessed outer surface is used to hold the contact pad in the mounting slot ( 331 ). The protruding central surface presses a plastic bag against the adiabatic sheet ( 21 ) to ensure a smooth and efficient seal. 
     The mounting frame ( 331 ) is a strip of stiff insulating material, has a central longitudinal through hole ( 334 ) corresponding to the protruding central surface of the contact pad ( 332 ), is mounted in the mounting slot ( 32 ) against the recessed surface of the contact pad ( 332 ) around the protruding central surface and holds the press ( 33 ) securely in the mounting slot ( 32 ). 
     The hinges ( 34 ) are formed respectively on the two ends at the rear edge, protrude down from the inner surface and correspond to and are mounted pivotally respectively in the two hinge slots ( 13 ) in the base ( 10 ), and each hinge ( 34 ) has a leaf ( 341 ), a pintle ( 342 ) and a resilient element ( 343 ). The leaf ( 341 ) protrudes down from the inner surface of the upper case ( 3 ) and corresponds to and is mounted pivotally in the corresponding hinge slot ( 13 ) in the base ( 10 ). The pintle ( 342 ) is formed on and protrudes in from the leaf ( 341 ) and is mounted rotatably in the mounting hole ( 132 ) in the corresponding hinge slot ( 13 ). The resilient element ( 343 ) is mounted around the pintle ( 342 ), keeps the upper case ( 3 ) from resting against the base ( 10 ) and may be a torsional spring. 
     With reference to  FIGS. 6 and 7   b , the power module ( 4 ) provides DC power to electrical components of the portable heat sealing apparatus and comprises at least one optional battery ( 41 ), an optional circuit board, an optional electric cord ( 42 ), an optional rectifier ( 43 ), an optional selector switch, an enabling switch ( 44 ), an optional safety switch ( 45 ) and an optional visual indicator ( 46 ) (such as an LED). 
     The at least one battery ( 41 ) is mounted in the battery compartment ( 15 ), connects to the contacts ( 151 ) in the battery compartment ( 15 ), is removable and provides DC power to operate the portable heat sealing apparatus. 
     The circuit board is mounted in the base ( 10 ) and connects electrical components of the portable heat sealing apparatus to a DC power source. 
     The electric cord ( 42 ) connects to an external AC power source and extends though the electrical cord hole in the rear wall into the body ( 10 ). 
     The rectifier ( 43 ) is mounted in the base ( 10 ), is connected to the electric cord ( 42 ) to convert AC power to DC power and provides DC power. 
     The selector switch is mounted in the base ( 10 ) and selects either the at least one battery ( 41 ) or the rectifier ( 43 ) as the DC power source. 
     The enabling switch ( 44 ) is mounted inside the base ( 10 ), protrudes through the outer surface and enables the portable heat sealing apparatus. 
     The safety switch ( 45 ) is a microswitch, is mounted inside the base ( 10 ), is aligned with the activation rod ( 31 ) and activates the portable heat sealing apparatus ( 43 ) when the upper case ( 3 ) is pressed toward the base ( 10 ). 
     The visual indicator ( 46 ) is connected in parallel with the heating element ( 24 ), shines when the portable heat sealing apparatus is operating, is mounted inside the base ( 10 ), protrudes through the outer surface and is connected electrically to the safety switch ( 45 ). 
     The hanger assembly ( 5 ) allows the portable heat sealing apparatus to be detachably mounted securely on a smooth surface and comprises a hanger panel ( 50 ) and at least one wall connector ( 60 ) or multiple suction cups ( 70 ). 
     The hanger panel ( 50 ) attaches to a vertical surface and the bottom surface of the base ( 10 ) and has a contact surface, an exposed surface and multiple optional hooks ( 51 ), at least one optional stationary hanger ( 52 ) or both. The contact surface attaches to a vertical surface. The exposed surface attaches to the base. The hooks ( 51 ) are formed on and protrude from the exposed surface of the hanger panel ( 50 ) and are engaged respectively by the transverse mounting slots ( 19 ) of the base ( 10 ) to securely hold the portable heat sealing apparatus. The at least one stationary hanger ( 52 ) is formed on and protrudes from the exposed surface of the hanger panel ( 50 ) and is complementary to and engaged respectively by the at least one hanging lip ( 18 ) on the base ( 10 ). 
     The at least one wall connector ( 60 ) connects the hanger panel ( 50 ) to a vertical surface, is connected securely to the contact surface of the hanger panel ( 50 ) and may be two-sided pressure tape, a magnet or the like. 
     The suction cups ( 70 ) are mounted detachably respectively in the transverse mounting slots ( 19 ) in the bottom surface of the base ( 10 ). 
     People skilled in the art will understand that various changes, modifications, and alterations in form and details may be made without departing from the spirit and scope of the invention.