Abstract:
A hand-held electric sealer used for sealing a plastic bag or the like, including a casing, a sealing mechanism, a press bar, and a safety device. The sealing mechanism has a heating wire, which produces heat for sealing the plastic bag or the like when turned on. The safety device controls the heating of the sealing mechanism, and stops the sealing mechanism from being triggered accidentally.

Description:
This is a continuation of application Ser. No. 09/739,990 filed on Dec. 18, 2000 now U.S. Pat. No. 7,034,252 which is a continuation application of Ser. No. 09/208,256 filed on Dec. 9, 1998, now U.S. Pat. No. 6,326,594 which is a continuation-in-part of application Ser. No. 09/132,687, filed Aug. 12, 1998, now U.S. Pat. No. 6,064,038 and Ser. 09/189,359, filed Nov. 9, 1998 now U.S. Pat. No. 6,232,579 both of which are continuations-in-part of application Ser. No. 08/917,358 filed on Aug. 26, 1997, now U.S. Pat. No. 5,854,466, all of which are incorporated by reference in their entireties therein. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to electric sealers, and more particularly to a hand-held electric sealer with safety means which controls the heating of the sealing mechanism, and stops the sealing mechanism from being triggered by an erroneous action. 
     A variety of electric sealers have been developed, and have appeared on the market. These conventional electric sealers are designed to be energized by AC power supply, or DC power supply. U.S. Pat. No. 5,142,123 discloses an electric an electric sealer energizable by internal battery set or external AC adapter. 
     SUMMARY OF THE INVENTION 
     It is one object of the present invention to provide an electric sealer which is hand-held and safe to use. It is another object of the present invention to provide an electric sealer which is energizable by an internal battery set or external AC adapter. It is still another object of the present invention to provide a hand-held electric sealer which includes means to stop the sealing mechanism from being triggered by an erroneous action. 
     According to one embodiment of the present invention, the hand-held electric sealer comprises a casing, a sealing mechanism, a press bar, and safety means. The sealing mechanism comprises a heat insulative base, a heating wire, and two metal locating plates. The heat insulative base has a projecting block on the middle. The heating wire is mounted on the projecting block of the heat insulative base. The metal locating plates are fastened to the heat insulative base at two opposite sides to hold down the heating wire. A heat resistive cover sheet may be fastened to the projecting block of the heat insulative base, and covered on the heating wire. The number of the heating wire may be increased if desired. The heat insulative base of the sealing mechanism can be made of ceramics, bakelite, heat insulative plastics, or any material that resists heat as high as about 200° C. The press bar has one end, namely the fixed end, pivotably connected to the casing, and an opposite end, namely the free end, mounted with a heat insulative block. When the press bar is pressed down, the heat insulative block is lowered with the free end of the press bar and forced against the heat insulative base of the sealing mechanism to clamp the mouth of the plastic bag, enabling the mouth of the plastic bag to sealed. The safety means controls the heating of the heating wire of the sealing mechanism, and stops the sealing mechanism from being triggered by an accident. The safety means can be a stop plate pivotably to the outside wall of the casing, and turned between a first position where the stop plate is suspended above the sealing mechanism to stop the heat insulative block of the press bar from contacting the projecting block of the heat insulative base of the sealing mechanism, and a second position where the stop plate is moved away from the sealing mechanism for enabling the heat insulative block of the press bar to be pressed against the projecting block of the heat insulative base of the sealing mechanism. In an alternate form of the present invention, the safety means comprises a shaft mounted in a hole inside the casing, a stop rod turned about the shaft, and a knob fixedly connected to the stop rod and extended out of a notch on the casing and operated by hand to turn the stop rod about the shaft between a first position where the sealing mechanism is not allowed to be triggered, and a second position where the sealing mechanism is allowed to be triggered. The safety means can be a safety switch, a press-button switch, or an electric connector, or a combination of them. When a press-button switch is used, a protective shielding means is provided for protection. The electric circuit is closed or, opened by operating the safety means of the safety switch, press-button switch or electric connector. In still another alternate form of the present invention, the sealing mechanism is installed in the free end of the press bar. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of a hand-held electric sealer according to a first embodiment of the present invention. 
         FIG. 2  is a perspective view of the first embodiment of the present invention. 
         FIG. 3  is a cross sectional view of the first embodiment of the present invention, showing the press bar not depressed. 
         FIG. 4  is similar to  FIG. 3  but showing the press bar depressed. 
         FIG. 5  is an exploded view of a hand-held electric sealer according to a second embodiment of the present invention. 
         FIG. 6  is an exploded view of a hand-held electric sealer according to a third embodiment of the present invention. 
         FIG. 7  is a top plain view of the third embodiment of the present invention, showing the arrangement of the electric circuit. 
         FIG. 8  is a sectional view of a part of the first embodiment of the present invention, showing an AC adapter inserted into the electric connector, the second terminal disconnected from the first terminal. 
         FIG. 9  is an exploded view of a hand-held electric sealer according to a fourth embodiment of the present invention. 
         FIG. 10  is a top plain view of the fourth embodiment of the present invention, showing the arrangement of the electric circuit. 
         FIG. 11  is an exploded view of a hand-held electric sealer according to a fifth embodiment of the present invention. 
         FIG. 12  is an exploded view of part of  FIG. 11 . 
         FIG. 13  is a schematic drawing showing the safety switch of the fifth embodiment of the present invention operated. 
         FIG. 14  is an exploded view of a hand-held electric sealer according to a sixth embodiment of the present invention. 
         FIG. 15  is a perspective view of the sixth embodiment of the present invention. 
         FIG. 16  is another perspective view of the sixth embodiment of the present invention when viewed from another angle. 
         FIG. 17  is an exploded view of a hand-held electric sealer according to a seventh embodiment of the present invention. 
         FIG. 18  is an exploded view of a hand-held electric sealer according to an eighth embodiment of the present invention. 
         FIG. 19  is an exploded view showing the detachable arrangement of the sealing mechanism according to the present invention. 
         FIG. 20  is a sectional view of an alternate form of the present invention, showing the sealing mechanism installed in the free end of the press bar. 
         FIG. 21  is similar to  FIG. 20  but showing the press bar depressed. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1-4 , a hand-held electric sealer in accordance with a first embodiment of the present invention is an electric sealer energizable by an internal battery set, comprised of a casing  10 , a spring holder  11 , a press bar  20 , a battery chamber  30 , and a sealing mechanism  40 . 
     The battery chamber  30  is defined within the casing  10 , comprising a front contact holder  31  transversely disposed at a front side, a rear contact holder  32  transversely disposed at a rear side, a pair of first metal contacts  33  and  34 , bilaterally provided at the front contact holder  31 , a pair of second metal contacts  35  bilaterally provided at the rear contact holder  32 , and two horizontal metal contacts  331  and  341  respectively forwardly extended from the first metal contacts  33  and  34 . According to this embodiment, the second metal contacts  35  are integral with each other battery set can then be installed in the battery chamber  30  between the front contact holder  31  and the rear contact holder  32  to provide DC power supply to the sealing mechanism  40 . The spring holder  11  is mounted in casing  10  between the horizontal metal contacts  331  and  341 . 
     The sealing mechanism  40  is mounted in the casing  10 , comprising a heat insulative base  42 , a heating wire  42 , two metal locating plates  43 , a heat resistant cover sheet  44 , and a compression spring  45 . The heat insulative base  41  comprises a flat projecting block  411  on the middle. The heating wire  42  is fastened to the projecting block  411  of the heat insulative base  41 . The locating plates  43  are fastened to the heat insulative base  41  at two opposite sides to hold the heating wire  42  in place. The heat resistant cover sheet  44  is covered on the projecting block  411  and the heating wire  42  to protect the heating wire  42 , and to provide a smooth surface. The heat resistant cover sheet  44  can be a meshed member made of teflon-coated metal wire. The heat insulative base  41  further comprises a bottom hole  412 . The compression spring  45  has a bottom end mounted in the spring holder  11 , and a top end inserted into the bottom hole  412 . Therefore, the sealing mechanism  40  is supported on the compression spring  45 , and can be moved up and down relative to the casing  10 . 
     The press bar  20  comprises a heat insulative block  21  at the bottom side of one end, namely the front end thereof, a heat resistant cover sheet  22  covered on the heat insulative block  21 , and a pair of lugs  23  bilaterally arranged in parallel at an opposite end, namely the rear end thereof. The lugs  23  each have a pivot pin  231 . The pivot pins  231  of the lugs  23  are respectively inserted into respective pivot holes  12  at the rear side of the casing  10  remote from the sealing mechanism  40 . Therefore, the press bar  20  is coupled to the casing  20 , and can be turned up and down about an axis relative to the casing  10 . When the press bar  20  is turned downwards, the heat insulative block  21  is pressed on the projecting block  411  of the heat insulative base  41  of the sealing mechanism  40 . The heat resistant cover sheet  22  is covered on the heat insulative block  21  to provide a smooth surface. The heat resistant cover sheet  22  can be a meshed member made of teflon-coated metal wire. Further, a spring plate  24  is provided, having a fixed end fastened to the press bar  20  and a free end stopped at a part of the casing  10 . The spring plate  24  imparts an upward pressure to the press bar  20 , causing the press bar  20  to be maintained in an “opened” position where the heat insulative block  21  is kept away from the projecting block  411  of the heat insulative base  41  of the sealing mechanism  40 . 
     A safety stop plate  14  is pivotably connected to the front side of the casing  10 . When the safety heat sealer is not in use, the safety stop plate  14  is turned upwards and forced into the gap between the heat insulative block  21  of the press bar  20  and the projecting block  411  of the heat insulative base  41  of the sealing mechanism  40  to prohibit the heat insulative block  21  of the press bar  20  from contacting the sealing mechanism  40 . When in use, the safety stop plate  14  is turned outwards and then downwards, enabling the heat insulative block  21  of the press bar  20  to be pressed against the projecting block  411  of the heat insulative base  41  of the sealing mechanism  40 . 
     A cover  50  is covered on the casing  10  to protect the sealing mechanism  40  and the battery chamber  30 . The cover  50  is comprised of a front cover plate  51 , which covers the sealing mechanism  40 , a battery cover plate  52 , which covers the battery chamber  30 , and a rear cover plate  53 , which covers the rear part of the casing  10 . The front cover  51  has an opening  511  through which the projecting block  411  of the heat insulative base  41  of the sealing mechanism  40  passes. 
     Further, a magnetic mounting plate  13  is fixedly provided at the back side (bottom side) of the casing  10 . By means of the magnetic mounting plate  13 , the hand-held electric sealer can be secured to a metal object for example the metal wall of a refrigerator by magnetic attraction. 
     The operation of the first embodiment of the present invention is outlined hereinafter with reference to  FIGS. 3 and 4  again. As illustrated in  FIG. 3 , when the hand-held electric sealer is not operated, the metal locating plates  43  are kept away from the horizontal metal contacts  331  and  341 , the heating wire  42  is disconnected from the DC power supply of the battery (which is installed in the battery chamber  30 ), and the safety stop plate  14  is stopped between the heat insulative block  21  of the press bar  20  and the projecting block  411  of the heat insulative base  41  of the sealing mechanism  40 . Therefore, pressing the press bar  20  does not cause the sealing mechanism  40  to work. When in use, as illustrated in  FIG. 4 , the safety stop plate  14  is turned away from the projecting block  411 , then the press bar  20  is depressed to force the heat insulative block  21  against the heat insulative base  41  of the sealing mechanism  40 , causing the metal locating plates  43  to be lowered with the heat insulative base  41  into contact with the horizontal metal contacts  331  and  341 , and the heating wire  42  is electrically connected to start the heat sealing operation. 
     When sealing the two thermoplastic flaps of an article, the thermoplastic flaps of the article are placed in between the heat insulative block  21  and the projecting block  411 , then the press bar  20  is depressed to force the metal locating plates  43  into contact with the horizontal metal contacts  331  and  341 . When the metal locating plates  43  touch the horizontal metal contacts  331  and  341 , the heating wire  42  is turned on to produce heat, thereby causing the thermoplastic flaps of the article to be sealed. After sealing, the press bar  20  is released from the hand, enabling the heat insulative base  41  and the metal locating plates  43  to be moved upwardly away from the horizontal metal contacts  331  and  341  by the compression spring  45 , and therefore battery power supply is cut off from the heating wire  42 . 
       FIG. 5  shows a hand-held electric sealer according to a second embodiment of the present invention. This embodiment is energizable by an external AC adapter. The structure and operation procedure of this second embodiment are similar to that of the aforesaid first embodiment with the exception of the arrangement of power supply. The second embodiment comprises a power socket  70  for receiving power supply from an AC outlet through an AC adapter. The power socket  70  has two opposite terminals respectively connected to the horizontal metal contacts  331  and  341  by electric wires  72  and  73 . Because no battery is used, the aforesaid battery chamber can be eliminated from the casing  10 . Therefore, the size of the casing  10  can be greatly reduced. Further, the safety stop plate  14  is pivotably connected to the outside wall of the casing  10  relative to the sealing mechanism  40  for safety control. 
       FIGS. 6 through 8  illustrate a hand-held electric sealer according to a third embodiment. This third embodiment can be energized by an internal battery set or an external AC adapter as desired. The electric connector, referenced by  90 , comprises a first terminal  91 , a second terminal  92  and a third terminal  93  respectively connected to the left-side first metal contact  33  and the two horizontal metal contacts  331  and  341  by respective electric wires  71 ,  72  and  73 . The left-side horizontal metal contact  331  and the left-side first metal contact  33  are separated from each other. The right-side horizontal metal contact  341  and the right-side first metal contact  34  are connected together. As illustrated in  FIG. 7 , the first terminal  91  and the second terminal  92  are electrically connected. When an AC adapter  80  is connected to the electric connector  90 , the second terminal  92  is forced away from the first terminal  91  (see  FIG. 8 ), i.e., the battery is off after installation of the AC adapter  80  in the electric connector  90 . Therefore, only battery power or AC power is exclusively provided to the sealing mechanism at a time. 
     The aforesaid third embodiment further comprises a safety switch  60  installed in the electric wire  72  between the second terminal  92  of the electric connector  90  and the left-side horizontal metal contact  331 . When not in use, the safety switch  60  is switched to off position to cut off the power supply. Under this condition, pressing the press bar  20  does not cause the sealing mechanism to work. Because the safety switch  60  can easily be achieved by conventional techniques, it is not described in detail. 
       FIGS. 9 and 10  illustrate a hand-held electric sealer according to a fourth embodiment of the present invention. According to this embodiment, the right-side horizontal metal contact  341  and the right-side first metal contact  34  are separated from each other, the first terminal  91  is connected to the left-side first metal contact  33  by one electric wire  71 , the second terminal  92  is connected to the left-side horizontal metal contact  331  by one electric wire  72 , the third terminal  93  is connected to the right-side horizontal metal contact  341  by one electric wire  73 , and the safety switch  61  is installed in an electric wire  74 , which is connected between the right-side first metal contact  34  and the right-side horizontal metal contact  341 . 
       FIGS. 11 through 13  illustrate a hand-held electric sealer according to a fifth embodiment of the present invention. This fifth embodiment comprises a safety switch  100 . The safety switch  100  is provided at the front side of the casing  10 , comprising a knob  101 , an electrically insulative stop rod  102 , and a shaft  103 . The shaft  103  is mounted in a hole  16  inside the casing  10 . The electrically insulative stop rod  102  is a substantially V-shaped rod turned about the shaft  103 . The knob  101  is fixedly connected to a part of the stop rod  102 , and extended out of a top notch  17  at the front side of the casing  10 . Further, a spring cap  151  is covered on a spring  15  inside the casing  10 , and forced upwards by the spring  15  to support the Press bar  20  in the open position. 
     Referring to  FIGS. 12 and 13  again, when not in use, the knob  101  is operated by hand to turn the stop rod  102  about the shaft  103  to a first position where the two opposite ends of the stop rod  102  are suspended above the horizontal metal contacts  331  and  341  to stop the metal locating plates  43  from contacting the horizontal metal contacts  331  and  341 . On the contrary, when using the hand-held electric sealer, the stop rod  102  is turned about the shaft  103  to a second position where the two opposite ends of the stop rod  102  are moved away from the horizontal metal contacts  331  and  341 , for enabling the metal locating plates  43  to be lowered with the sealing mechanism  30  into contact with the horizontal metal contacts  331  and  341 . This safety switch  100  can be used in either of the aforesaid first, second and third embodiments, or any similar electric sealer. 
       FIGS. 14 through 16  illustrate a sixth embodiment of the present invention. According to this embodiment, the sealing mechanism is immovable, i.e., the sealing mechanism cannot be moved vertically. The hand-held electric sealer of the sixth embodiment is energizable by a battery set. According to this sixth embodiment, the sealing mechanism  40  comprises a heat insulative base  41 , a heating wire  42 , two metal locating plates  43 , and a heat resistant cover sheet  44 . When assembled, the sealing mechanism  40  is disposed above the front contact holder  31 , and the metal locating plates  43  are maintained in contact with the horizontal metal contacts  331  and  341 . The front cover plate  51  holds the sealing mechanism  40  in place, enabling the metal locating plates  43  to be maintained in contact with the horizontal metal contacts  331  and  341 . 
     The aforesaid fifth embodiment further comprises a safety device, which can be a safety switch  75  or a press button switch  76 . Both of the safety switch  75  and the press-button switch  76  may be simultaneously installed. In this case, the heating wire  42  can be turned on only when the safety switch  75  and the press-button switch  76  are both switched on. Referring to  FIGS. 14-16  again, the left-side first metal contact  33  and the left-side horizontal metal contact  331  are separately installed and an electric wire  721  is connected between the left-side first metal contact  33  and the left-side horizontal metal contact  331 . The safety switch  75  is installed in the electric wire  721  to switch on/off the circuit. Alternatively, the right-side first metal contact  34  and the right-side horizontal metal contact  341  can be separately installed and connected by an electric wire  731 , and the press-button switch  76  can be installed in the electric wire  731  and controlled to close/open the circuit. If desired, the second metal contacts  35  can be separated from each other, and connected by an electric wire in which the safety switch or press-button switch can be installed and operated to close/open the circuit. The application of the safety switch and/or press-button switch can be used in the aforesaid first embodiment. 
     Referring to  FIG. 14  again, the sealing mechanism  40  can have a plurality of heating wires  42 . The cross section of the heating wire(s)  42  can have a circular shape, polygonal shape, or any of a variety of shapes. 
     When the safety switch  75  is switched on, the two thermoplastic flaps of the article to be sealed are put in between the heat insulative block  21  of the press bar  20  and the projecting block  411  of the heat insulative base  41  of the sealing mechanism  40 , then the press bar  20  is pressed down, and at the same time the press-button switch  76  is depressed by one finger, causing the heating wire(s)  42  to produce heat, enabling the two thermoplastic flaps of the article to be sealed. When the press-button switch  76  is released, the heating wire(s)  42  is (are) off. After use, the safety switch  75  is switched off. 
       FIG. 17  shows a seventh embodiment of the present invention. According to this embodiment, the sealing mechanism is immovable, and energizable by an AC adapter. As illustrated, a front contact holder  31 , which holds two horizontal metal contacts  331  and  341 , and a power socket  70  are mounted in the casing  10 . The power socket  70  receives external power supply, and has two opposite terminals respectively connected to the horizontal metal contacts  331  and  341  by respective electric wires  72  and  73 . The aforesaid safety switch  75  and press-button switch  76  can be selectively installed in the electric wire  72  or  73 , or connected in series in the electric wire  72  or  73 . Two or more safety switches or press-button switches may be installed. When a plurality of safety switches or press-button switches are installed, the sealing mechanism can be operated only when all safety switches or press-button switches are switched on. The installation and operation of the switches of the seventh embodiment may be used in the aforesaid second embodiment. 
       FIG. 18  illustrates an eighth embodiment of the present invention. The sealing mechanism according to this eighth embodiment is immovable, and energizable by an internal battery set or an external AC adapter. According to this embodiment, the casing  10  comprises a battery chamber  30  for holding a battery set. The battery chamber  30  comprises a front contact holder  31  transversely disposed at a front side, a rear contact holder  32  transversely disposed at a rear side, a pair of first metal contacts, namely, the left-side first metal contact  331  and the right-side first metal contact  34  bilaterally provided at the front contact holder  31 , a second metal contact  35  bilaterally provided at the rear contact holder  32 , and two horizontal metal contacts namely a left-side horizontal metal contact  331  and a right-side horizontal metal contact  341  respectively disposed in contact of the first metal contacts  33  and  34 . Please see also  FIG. 8 , an electric connector  90  is mounted in the casing  10 . The electric connector  90  comprises a first terminal  91 , a second terminal  92 , and a third terminal  93 . The terminals  91 ,  92  and  93  are respectively connected to the left-side first metal contact  33 , the left-side horizontal metal contact  331  and the right-side horizontal metal contact  341  by electric wires  71 ,  72  and  73 . Before the installation of an AC adapter  80  in the electric connector  90 , the first terminal  91  and the second terminal  92  are electrically connected. When an AC adapter  80  is connected to the electric connector  90 , the second terminal  92  is forced away from the first terminal  91 , i.e., the battery is off after installation of the AC adapter  80  in the electric connector  90 . Therefore, only battery power or AC power is exclusively provided to the sealing mechanism at a time. A safety switch and a press-button switch (not shown) can be connected in series, and installed in the electric wire  72 . Alternatively, a safety switch and a press-button switch may be connected in series, and installed in the position corresponding to the position of the safety switch  61  of the aforesaid fourth embodiment. The operations of the sealing mechanism, the safety switch and the press button switch are similar to the aforesaid sixth and seventh embodiments. 
     Referring to  FIG. 19 , the sealing mechanism can be made detachable. As illustrated, the horizontal metal contacts  331  and  341  each have an upright lug  332  or  342 , which has a locating hole  333  or  343 . The metal locating plates  43  of the sealing mechanism  40  each have a bolt  431  at an outer side. By inserting the bolts  431  of the metal locating plates  43  into the locating holes  333  and  343  at the metal contact plate  331  and  341 , the sealing mechanism  40  is coupled between the horizontal metal contacts  331  and  341 . Because the sealing mechanism  40  is detachable, it can be replaced with a new one when its heating wire or heat resistant cover sheet is damaged. 
     Referring to  FIGS. 20 and 21 , the sealing mechanism  40  can be installed in the free end of the press bar  20 . As illustrated, the press bar  20  comprises two metal press plates  25  respectively connected to the sealing mechanism  40 . The casing  10  comprises a heat insulative block  18  at the top corresponding to the sealing mechanism  40  at the press bar  20 . A switch  19  is installed in the casing  10 , and controlled to turn on/off the sealing mechanism  40 . When the press bar  20  is pressed down to force the sealing mechanism  40  against the heat insulative block  18 , the metal press plates  25  are simultaneously pressed on the switch  19 , causing the switch  19  to be switched on, and therefore the electric circuit is closed, enabling electricity to be transmitted to the sealing mechanism  40 . In  FIGS. 20 and 21 , the sealing mechanism  40  is movably provided at the free end of the press bar  20  (the sealing mechanism  40  is coupled to the free end of the press bar  20  and supported on a spring member). Alternatively, the sealing mechanism  40  can be fixedly secured to the free end of the press bar  20 . 
     The design of arranging the sealing mechanism at the press bar can be used in any of a variety of hand-held electric sealers, including battery-operated electric sealers, AC electric sealers. AC/DC dual mode electric sealers. 
     It is to be understood that the drawings are designed for purposes of illustration only, and are not intended as a definition of the limits and scope of the invention disclosed.