Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B3/00—Ohmic-resistance heating
  • H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
  • H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
  • H05B3/14—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
  • H05B3/145—Carbon only, e.g. carbon black, graphite
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C17/00—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces
  • B05C17/005—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces for discharging material from a reservoir or container located in or on the hand tool through an outlet orifice by pressure without using surface contacting members like pads or brushes
  • B05C17/00523—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces for discharging material from a reservoir or container located in or on the hand tool through an outlet orifice by pressure without using surface contacting members like pads or brushes provided with means to heat the material
  • B05C17/00526—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces for discharging material from a reservoir or container located in or on the hand tool through an outlet orifice by pressure without using surface contacting members like pads or brushes provided with means to heat the material the material being supplied to the apparatus in a solid state, e.g. rod, and melted before application
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C17/00—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces
  • B05C17/005—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces for discharging material from a reservoir or container located in or on the hand tool through an outlet orifice by pressure without using surface contacting members like pads or brushes
  • B05C17/00523—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces for discharging material from a reservoir or container located in or on the hand tool through an outlet orifice by pressure without using surface contacting members like pads or brushes provided with means to heat the material
  • B05C17/00546—Details of the heating means
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B3/00—Ohmic-resistance heating
  • H05B3/40—Heating elements having the shape of rods or tubes
  • H05B3/42—Heating elements having the shape of rods or tubes non-flexible
  • H05B3/46—Heating elements having the shape of rods or tubes non-flexible heating conductor mounted on insulating base

Definitions

• the present invention relates to portable electronic devices, and more particularly, to portable electronic devices that dispense liquefied substances, such as adhesive from a glue gun.
• Glue guns dispense melted glue to provide adhesive for affixing materials or objects to each other.
• a glue gun is an important tool that hobbyists, craftsman, and other project enthusiasts use for certain projects when accurate placement of adhesive is required.
• Glue guns typically include a barrel member with an internal melting chamber and an electrical heating element used for heating the chamber.
• the internal melting chamber is made of a thermally conductive material, such as aluminum. This is shaped to receive a glue stick, which is a solidified supply of adhesive (and, in its solid form, looks much like a small candle).
• the heating element generates heat from electrical energy flowing through it, which heats the melting chamber to melt an end portion of the glue stick therein.
• a user To operate most conventional glue guns, a user first inserts a glue stick and plugs an electrical cord from the tool into an AC electrical outlet to supply electricity and begin heating the melting chamber. After a few minutes of heating, the glue gun will have melted at least part of the glue stick and is ready for use. Once the glue gun is ready, a user grips the tool by a handle with one hand, positions it while maintaining the plug in the electrical outlet and maneuvering the corresponding electrical cord, and presses a trigger on the handle to force molten adhesive material out of the melting chamber through a nozzle at the end of the barrel. As long as the tool is plugged in, the barrel stays hot and will continue to dispense molten adhesive upon depressing the trigger.
• An apparatus for dispensing liquefied adhesive includes a chamber having an opening at one end thereof for allowing a supply of solidified adhesive to be inserted therein and a nozzle opening at another end of the chamber, configured for allowing molten adhesive to flow therethrough.
• a heater is associated with the chamber and operable to apply heat to the chamber sufficient to melt a portion of a solidified adhesive inserted in the chamber.
• the heater is comprised of a semiconductive material.
• the heater is comprised of a resistive heating wire material substantially wrapped around a circumference of a longitudinal portion of the chamber.
• the liquefied adhesive dispensing apparatus is capable of cordless operation.
• the apparatus further includes a power source in electrical communication with the heater that is capable of providing for cordless operation.
• a temperature sensor is also included for detecting the temperature of the chamber, wherein output from the sensor is provided as an input to circuitry that switches off electrical power to the heater or modifies a duty cycle of a pulse width modulation circuit once the heater reaches a threshold temperature.
• the circuitry is an integrated circuit.
• the apparatus includes a barrel portion and a grip portion, and the barrel portion includes a window by which a user can discern whether an adhesive has been inserted.
• the apparatus includes at least one sensor is in communication with an integrated circuit to detect if the apparatus has not been in use for a predetermined amount of time while the DC power source is powered on.
• the apparatus is operable in a power-save mode after a predetermined time of non-use.
• a light may be incorporated for illuminating a workpiece that receives molten adhesive from the nozzle.
• the heater in the apparatus may be comprised of a resistance wire such as nichrome, where certain sections of the wire are wrapped about the chamber, and the resistance of the heater is lower in at least some sections that are not in proximity to the chamber.
• a thin polyimide film layer may be applied to the chamber and a thin mica sheet may be applied beneath the wire.
• FIGURE 1 is a side cross-sectional view of an exemplary embodiment of a liquid dispensing apparatus constructed in accordance with aspects of the present invention
• FIGURE 2A is a magnified exterior view of a heater assembly that may be utilized in an exemplary embodiment of a liquid dispensing apparatus, the cross-section of which is depicted in FIGURE 1;
• FIGURE 2B is a magnified cross-sectional view of the assembly depicted in
• FIGURE 2A
• FIGURE 3 illustrates a magnified perspective view of a heating chamber that may be utilized in an exemplary embodiment of a liquid dispensing apparatus
• FIGURE 4 illustrates a second magnified perspective view of a heating chamber that may be utilized in an exemplary embodiment of a liquid dispensing apparatus
• FIGURE 5 is a magnified perspective view of the exterior of the heating assembly utilizing the heating chamber in FIGURES 3 and 4;
• FIGURE 6 is a further magnified perspective view of the exterior of the heating assembly depicted in FIGURE 5;
• FIGURE 7 is a front cross-sectional view of the heating assembly depicted in
• FIGURES 8 A, 8B, 8C, 8D, 8E, 8F, and 8G depict views of a heater material that may be utilized in a liquid dispensing apparatus in accordance with an embodiment of the present invention.
• FIGURE 9 is a block diagram of connections to a controller that may be incorporated in a liquid dispensing apparatus in accordance with the present invention.
• FIGURE 10 is a state diagram indicating the temperature regulation of a heater in the liquid dispensing apparatus in accordance with an embodiment of the present invention.
• FIGURE 11 is a schematic of a printed circuit board and associated circuitry for use in a liquid dispensing apparatus in accordance with an embodiment of the present invention
• FIGURE 12 is a schematic of a second printed circuit board and associated circuitry for use in a liquid dispensing apparatus in accordance with an embodiment of the present invention
• FIGURES 13A, 13B, 13C and 13D illustrate a heater material and assembly utilized in an exemplary embodiment of a liquid dispensing apparatus
• FIGURE 14 illustrates an arrangement of a conventional PTC heating element in a barrel assembly of a glue gun.
• the following discloses technology for enabling power-efficient and safe use of a portable electronic apparatus such as a glue gun.
• the tool is designed so as to allow for cordless operation, and the sizing, shape and composition of the heater and the motion sensing, temperature sensing and timing circuitry that are incorporated into the device maximize the amount of heat output to thereby minimize the energy required for powering the tool.
• the invention's scope is not so limited. Even taken singly, many of the improvements discussed below constitute significant advances in the field. Combining one or more of these improvements provides an extremely versatile and vastly improved tool.
• FIGURE 1 is a side cross-sectional view of an exemplary embodiment of a portable electronic apparatus 10 constructed in accordance with aspects of the present invention.
• the apparatus is configured for applying heat to liquefy solid material, such as an adhesive (not shown), fed therein, and may be referred to as a glue dispensing apparatus.
• the apparatus includes a housing 11 constructed of two housing halves (one of which is shown in FIGURE 1) preferably molded of heat resistant plastic.
• the housing includes a barrel portion 12 and a grip portion 13 that a user grasps and holds in one hand.
• the housing encases or has mounted thereto several components of the apparatus, including a heating assembly 14, an advancement mechanism 15, a trigger 16, a heat sink 9, and a power source 17.
• the apparatus is adapted to receive sticks of substantially solid material, such as adhesive, into one end of the housing, introduce the stick of adhesive to the heating assembly by the advancement mechanism actuated by the trigger, and to eject liquefied material from a nozzle 19 of the heating assembly at the other end of the housing.
• a clear window 8 is provided in the housing atop the barrel portion to enable users to see whether a glue stick is inserted or how much of the glue stick already has been ejected from the nozzle 19 as liquefied material.
• the apparatus may additionally include one or more lights, such as light emitting diodes (LEDs) 18a, 18b, 18c for providing alerts to the user or for illuminating an object that is to receive the liquefied material.
• the apparatus may include a printed circuit board 20 for providing heating control.
• the apparatus may additionally include one or more tilt sensors 21a, 21b.
• FIGURE 2A depicts heating assembly 14 of FIGURE 1 disposed in the barrel portion of the housing
• FIGURE 2B is a cross-sectional view of the heating assembly.
• a heating chamber 23 has a longitudinal opening therethrough, the rear end of which defines an entrance for receiving a stick of adhesive 25, which may be advanced into the cooperatively shaped heating chamber by an advancement mechanism, as will be described in detail below.
• the heating chamber can accommodate 7.2 mm diameter all- purpose glue sticks in lengths greater than 100 mm.
• the heating chamber further defines a front end that forms an exit through which the melted glue is ejected.
• integrally formed with the heating chamber is a nozzle portion that extends outwardly from the front end of the barrel portion.
• the nozzle defines an opening fluidly communicating with the chamber so as to allow a stick of adhesive melted in the chamber to flow outwardly onto a workpiece.
• a nozzle guard or sleeve 28 may be utilized to cover the heating chamber at the nozzle portion.
• the nozzle sleeve is fixed to the exterior of the nozzle adjacent the housing.
• the nozzle sleeve is made of silicon, flexible rubber, or other material that insulates the metallic nozzle to protect an operator from the heat that may flow through the nozzle from the heating elements.
• the nozzle portion of the heating chamber may further include an anti-drip mechanism, comprised of a spring 27a and a ball valve 27b, to prevent leakage of melted glue from the heating chamber when the apparatus is not in use.
• an anti-drip mechanism comprised of a spring 27a and a ball valve 27b, to prevent leakage of melted glue from the heating chamber when the apparatus is not in use.
• Incorporating a ball bearing stop mechanism substantially improves the performance of the device by eliminating or significantly reducing the unintended dripping of liquefied adhesive from the nozzle of the tool.
• FIGURE 1 perspective views of another heating chamber that may be used in an apparatus in accordance with the present invention are provided in FIGURES 3 and 4. While the nozzle portion and heat body portion are shown as a one-piece construction, it will be appreciated that a nozzle may be constructed separate from a heat body.
• the heat body is preferably formed of a low density, high thermal conductive material, such as aluminum.
• the material may be die cast Grade 356 or 360 aluminum.
• FIGURES 3 and 4 a portion of the chamber that abuts against the flange is rectangular in shape. This is in contrast with the heating chamber in FIGURES 2A and 2B, which is cylindrical in shape. Differently-shaped heating chambers may preferably be used with different types of heaters or different heater materials.
• the heating chamber has been specifically designed to reduce thermal mass, while still providing users with sufficient durability and melted glue on demand.
• aluminum is characterized by having a low density and high conductivity, which enables an aluminum nozzle to heat more quickly than those found in conventional glue guns.
• the heating chamber is coupled to an elongated inlet sleeve 22.
• the inlet sleeve defines a flange portion fitted over the rear end of the heating assembly 14.
• the inlet sleeve has an interior passageway that is disposed coaxially with the heating chamber, through which the stick of adhesive is introduced into the rear end of the heating chamber.
• a guide collar 29 is disposed at the rear end of the barrel in coaxial relation to the inlet sleeve.
• the guide collar provides a guide opening coaxial with the heating chamber to guide the stick of adhesive and maintain the stick of adhesive in proper alignment with the heating chamber.
• the inlet sleeve and the guide collar are preferably made of silicone or silicon rubber.
• the inlet sleeve is preferably in sealing engagement with the heating chamber for preventing melted adhesive from escaping the heating chamber.
• PTC heating elements typically have an operating life of no more than approximately 1000 hours, most glue guns are discarded after a certain amount of usage.
• a conventional PTC heater is generally shaped as a box 140, such that only a single surface of the PTC heater contacts with only a small area on the surface of a cylindrically-shaped aluminum barrel 141. This arrangement usually is sufficient to generate adequate heat to melt the adhesive in the chamber, but there is significant heat loss from the sides that are not in contact with the barrel.
• the heating assemblies in several embodiments of the present invention include one or more heating elements disposed in an improved heat transfer relationship with the heat body, as described with reference to FIGURES 5-7.
• a plurality of heating elements 50 are disposed at the forward end of the heating chamber, located close to the nozzle portion.
• the heating elements are preferably secured to or maintained adjacent the heat body by either mechanical techniques, i.e., brackets, clamps, screws, etc. 54 or chemical techniques, i.e., epoxy, adhesives, to maintain a positive connection therebetween.
• the housing may be specifically designed with flanges, tabs, or other interior structure that retains the heating elements in contact with the heat body once assembled.
• the heater 50 is a solid graphite-based material that closely surrounds a small portion of the heat body proximate to the nozzle portion, thereby melting a volume of adhesive 25 near the exit point of the nozzle 19 where glue is to be dispensed.
• the size and shape of the heater are designed to require only a minimum amount of energy for dispensing liquefied adhesive.
• the heating elements are held in place via clamps 54 constructed of a metallic material, such as copper, or beryllium copper (BeCu) rings that act as electrical contacts.
• the clamps may also be used as power source connection terminals 52 for connecting the heating elements in electrical communication with the power source. Regardless of the coupling technique, the heating elements are electrically connected to the power source through circuitry such that electricity is routed through the heating elements or portions thereof.
• the heating element(s) in this embodiment is formed of a substantially rigid semi-conductive material such as germanium, graphite, or silicon, or a material containing such a semi-conductive material.
• the electrical resistivity is preferably approximately 750 micro-Ohm cm or greater, and more preferably approximately 1,500 micro-Ohm cm or greater. In other embodiments, the electrical resistivity of the heating elements is greater than approximately 3,000 micro-Ohm cm.
• the heating elements may have a density in the range of approximately 1.0 to 2.2 g/cc, although other ranges are contemplated to be within the scope of the present invention.
• the heating elements may be electrically isolated from the heat body. In several embodiments, this may be accomplished by disposing an electrical isolation barrier, such as a dielectric layer, between the heating elements and the heat body.
• the electrical isolation barrier may be formed by a polyimide substrate, preferably chemically secured via adhesive or the like to one of the surfaces.
• One such dielectric polyimide substrate that may be practiced with the present invention is sold as Kapton® tape, commercially available from DuPont®.
• the outer surface of the heating elements or the heat body may be coated with a thin dielectric film, such as a phenolic coating.
• the heat body may be constructed from anodized aluminum, the anodized surface of the heat body performing as a dielectric between the heat body and the heating elements. It will be appreciated that the thickness of the electrical isolation barrier should be kept to a minimum to both act as a electrical insulator but also to minimized the possible reduction of heat transfer between the heat body and the heating elements. [0042] Various insulation techniques may be practiced with the present invention.
• a layer of insulation may envelope or overlay a portion of or substantially all of the exposed surfaces of the heating elements.
• the thermal insulation layer can handle upper temperatures ranges around 500 degrees F.
• the thermal insulation layer is constructed of commercially available calcium- magnesium-silicate; although other insulation layers may be used, such as aluminum-lined fiberglass.
• FIGURES 8 A, 8B, 8C, and 8D illustrate several views (top, bottom, side and perspective views, respectively) of a serpentine-shaped configuration for graphite foil that is to be utilized as a heater for a glue gun in accordance with one exemplary embodiment of the present invention.
• the graphite foil 80 is laminated between polymide sheets 82 (illustrated in FIGURES 8 A and 8C on one side).
• the use of graphite foil as a heater is illustrated in FIGURE 2A, where the graphite foil 80 is wrapped around the heating chamber of the glue gun and fixed in place via clamps 83.
• several pieces of graphite foil can be separately wrapped around the sleeve.
• FIGURE 8E and 8F illustrate how graphite foil 80 in FIGURES 8 A, 8B, and
• FIGURE 8C can be wrapped about the heating chamber 23, between flange 84 before the nozzle portion and the silicon sleeve 22.
• the graphite foil 80 is preferably secured by clamps 83 as illustrated in FIGURE 2A, other techniques for affixing or otherwise maintaining the foil closely to the heating chamber may be used without departing from the invention.
• FIGURE 8G further illustrates where polymide film tape 82 is attached to or contacts against the heating chamber, whereas tips of the graphite foil 80 are exposed to the surface (but preferably, not the heating chamber) to provide electrical contacts with a power source to engage the heating assembly.
• FIGURE 2B as a cross-sectional view, illustrates the relationship between the heater 80 and the longitudinal opening within the heating chamber 23.
• FIGURE 13 A, 13B and 13C illustrate yet another heater assembly for a glue gun in accordance with a preferred embodiment of the present invention.
• the heating element 130 is comprised of a resistive heating wire, preferably, nichrome, comprising a combination of nickel and chromium, as a coil heater.
• the resistance wire sized in length and diameter to provide the proper resistance required for operation, can be wound around the heating chamber.
• the nichrome resistivity is 100-150 uOhm-cm, and the density is approximately 8.4 g/cc.
• the section of wire 132a, 132b not directly in contact with the heating chamber is braided with an additional section of wire to cause this section to be lower in resistance due to the higher cross-sectional area. This ensures that the heating effect is confined to that section of wire that is in direct contact with the heating chamber.
• FIGURE 13B illustrates the windings of the resistance wire 130 around the heating chamber.
• the windings are wrapped closely around the heating chamber, under tension to improve heat transfer from the wire to the heating chamber, and spaced apart from each other.
• the heating chamber 23 may be covered with a dielectric material, such as polymid, anodize, etc., between the coil to provide electrical insulation. Due to the high power density associated with this resistance wire heating element, seven thin layers of mica are used as the dielectric insulation.
• FIGURE 13C is a close-up illustration of the heating chamber 23, the wire 130 and dielectric insulation 135.
• a resistive wire heater particularly, nichrome wire heater
• a cordless glue gun tool there are particular advantages to incorporating a resistive wire heater, particularly, nichrome wire heater, with a cordless glue gun tool. Because a resistive wire heater can be formed around a heat body so as to wrap closely about its circumference, there is comparatively less heat loss than with a conventional PTC heater, which is exposed to and contacts with a heat body only at a small surface area. Accordingly, the resistive wire heater heats with greater efficiency, which is important when the heater is used in conjunction with a cordless power source that provides less voltage and current than a standard alternating current source, and provides power for only a limited duration of time before discharge. Other features, such as the use of a thermistor, auto shut-off, etc., as described below, in concert with the power efficient heating provided by a nichrome wire heater, provide additional advantages when used in a cordless glue gun tool.
• one layer is a thin polyimide film 135 applied to the heating chamber and an additional layer is a thin mica sheet 136 directly beneath the resistance wire 130.
• This embodiment takes advantage of the high power densities tolerated by mica, but allows fewer layers of mica to be used. Typically, several layers of mica are used due the tendency of mica to crack. The power density in this embodiment is diminished by the time the energy reaches the polyimide film, and since the polyimide film will not crack, fewer layers of mica are needed, thus maximizing the dielectric insulation and minimizing the thermal insulation between the resistance wire and the nozzle.
• the heating elements due to their resistivity, heat to approximately 500 degrees F when electricity is supplied thereto.
• power is supplied by a power source 17, such as a battery pack, selectively attached to the bottom of the grip portion by techniques known in the portable power tool art.
• the heating assembly further includes a temperature sensor 70.
• the temperature sensor is suitably mounted to the heat body and is capable of detecting the temperature of the heat body and outputting an appropriate signal indicative of the temperature of the heat body.
• FIGURE 5 shows that the temperature sensor may be attached via a clamp 72, and leads 71 may connect it to a controller.
• the temperature sensor may be a thermistor.
• FIGURE 6 provides a magnified view of the clamp for the temperature sensor, along with the clamps for the heater assembly in close proximity.
• FIGURE 7 illustrating a front cross-sectional view, the temperature sensor 70 is shown, surrounded by heater 50, with a glue stick 25 disposed therein.
• the apparatus is manually operated and includes a trigger 16 that is pivotally connected to the housing.
• the trigger is configured to be conveniently actuatable by the index finger (or other fingers, singly or in combination) of the user's hand that is gripping the grip portion.
• a stabilizer (not shown) may be pivotally attached by pivot pins to the front portion of the housing. When the stabilizer pivots from an inoperative position to an operative position, the user can rest the apparatus on a flat surface such as a table or workbench such that the stabilizer and a resting surface of the grip portion cooperate to support the apparatus in an upright position.
• the stabilizer and the resting surface are configured in such a way that the apparatus may be supported by the two structures in a "resting position.” It can be appreciated that the stabilizer and resting surface may be altered or modified to adjust the distance between the nozzle and the workpiece in the resting position.
• the advancement mechanism functions to advance the stick of adhesive into the heating chamber upon actuation of the trigger.
• the advancement mechanism includes a carriage member 100 slidably mounted in the housing, behind the inlet sleeve 22 (shown in FIGURE 2A).
• the carriage member is preferably molded of a single piece of a suitable material, such as plastic resistant to the temperatures employed.
• the carriage has a longitudinal bore, through which the stick of adhesive passes.
• the hole is preferably sized somewhat larger than the outside diameter of the stick of adhesive to avoid jamming and to allow easy insertion.
• the carriage is preferably provided with longitudinal rails 100 on each side that fit into corresponding slots on the housing, for guiding the path of travel of the carriage.
• the carriage has a transverse opening in communication with the longitudinal opening through which a gripper member 102 passes.
• the gripper member includes a head portion and a lower portion defining a somewhat transverse lever.
• the gripper member is pivotally mounted to the carriage at the head portion.
• the head portion further includes a protrusion or tooth for gripping the glue stick when actuated by the trigger.
• the gripper member is coupled to the trigger through appropriate linkage.
• the linkage includes a linkage member pivotally attached to the lower portion of the gripper and pivotally attached to the upper portion of the trigger. When assembled, the linkage member is disposed somewhat parallel to the glue stick.
• the squeezing action of the trigger causes the carriage to advance forwardly, thereby advancing the stick of adhesive into the heating chamber.
• a spring is ' secured from the trigger to a trigger spring attachment point for returning the trigger to an initial position upon release of pressure imparted on the trigger.
• the apparatus may include other components and/or features.
• the apparatus may include a light 18a disposed on the barrel portion of the apparatus for emitting light onto the area of discharged adhesive.
• the apparatus includes a power source, which in the embodiment shown, may be selectively attached to the grip portion.
• the power source 17 may be a battery or battery pack comprised of one or more rechargeable batteries or battery cells, for example, Nickel Cadmium (NiCd), Nickel Metal Hydride (NiMH), Lithium, or Lithium ion batteries, just to name a few. Particularly, a pack of four AA NiMH rechargeable batteries provides approximately 20 Watts of power to the semiconductive heating elements. While rechargeable batteries or battery cells are preferred, non- rechargeable batteries or other power storage sources may be used.
• the power source includes a number of Nickel Metal Hydride (NiMH) batteries encased within a power source housing detachably coupled to the grip portion to provide a nominal voltage of between approximately 3.0 and 6.0 volts.
• NiMH Nickel Metal Hydride
• FIGURE 9 is a block diagram of one exemplary embodiment of a system that may be practiced with the present invention.
• the system includes the heating elements 93 electrically connected to the power source 90 (or, power storage source) through an on/off switch 91.
• the system also includes a controller 94, that outputs control signals to a controllable switch 92 to either (i) close the switch so that electricity may flow from the power source 90 to the heating elements 93 or (ii) open the switch so that electricity is prohibited from flowing to the heating elements 93.
• the controller may include a logic system for determining the operation of switch and other components hereinafter described.
• the logic may be implemented in a variety of configurations, including but not limited to, analog circuitry, digital circuitry, processing units, and the like.
• the controllable switch may be replaced by a suitably configured pulsing circuit, such as a pulse width modulation (PWM) circuit, for modulating the power supplied to the heating elements.
• PWM pulse width modulation
• the pulsing circuit may be arranged by one of ordinary skill in the art, and will not be described in detail here.
• the controller may include a processing unit, a memory, and input/output (I/O) circuitry connected in a conventional manner.
• the memory may include random access memory (RAM), read only memory (ROM), or any other type of digital data storage means.
• the I/O circuitry may include conventional buffers, drivers, relays and the like, for sending device appropriate signals to the switch or a pulse width modulation (PWM) circuit and to other components hereinafter described.
• PWM pulse width modulation
• the controller 94 is further electrically connected to the temperature sensor 95 for receiving suitable signals corresponding to the temperature of the heat body.
• the temperature sensor may be a thermocouple or thermister connected to the heat body 96 in a conventional manner.
• the controller monitors the temperature of the heat body by receiving the output of the temperature sensor through an appropriate sensor specific interface, and controls the operation of the switch or PWM circuit for maintaining the temperature of the heat body above or between the desired temperature range. It will be appreciated that the controller may be programmed to continuously or selectively alter the duty cycle of the PWM circuit when maintaining the temperature of the heated heat body within a desired range.
• FIGURE 10 is a state diagram illustrating how the heater responds to the temperature sensor, in accordance with an exemplary embodiment of the present invention. As can be seen, the temperature of the nozzle varies over time as the heater is applied and withdrawn.
• the temperature of the nozzle continues to rise, as detected by the temperature sensor.
• the temperature sensor continues to provide readings to a controller (or alternatively, a comparator that can be implemented in analog circuitry).
• a controller or alternatively, a comparator that can be implemented in analog circuitry.
• the controller sends a signal for the heater to be turned on once again.
• the temperature continues to fall, but then rises. This process is continued to regulate the temperature to be substantially between the upper and lower threshold.
• the apparatus optionally may include a power save mode.
• a timing signal is generated by a trigger switch and transmitted to the controller.
• the controller receives the timing signal and starts a clock.
• the controller monitors the clock until a second timing signal is received from the trigger switch, which results in resetting the clock. If, however, the second timing signal is not received before a preselected time period, for example, five minutes, the controller automatically shuts off power to the heating elements for enhancing power source life.
• a status indicator such as a light 18b or 18c in FIGURE 1, may be provided to indicate to the user when the apparatus in the power save mode.
• one or more sensors may be used, such as tilt or vibration sensors 21a, 21b shown in FIGURE 1.
• the controller maintains a running clock, which is reset upon detecting movement from at least one of the two sensors. If a tilting movement or vibration is not experienced within a preselected time period, for example, five minutes, then the controller automatically shuts off power to the heating elements for enhancing power source life. Again, a status indicator may be provided to indicate to the user when the apparatus is in power save mode.
• two sensors are incorporated into the apparatus for detecting tilt movement or vibration from two axes.
• the apparatus may include a low power detection circuit.
• the circuit can be utilized to detect a low power condition, an operational voltage drop by the electrical power source, or current flowing through the heating elements.
• the circuit functions to indicate by way of a light disposed on the apparatus, a low power condition of the power source or an operational drop in voltage. This is accomplished by comparing the voltage produced by the power source (across the source) during use, hereinafter referred to as the operation voltage, with a preselected reference voltage.
• the reference voltage if the power source is a battery, may be selected between the voltage of a fully charged battery and the voltage of a partially or fully discharged battery.
• the circuit is configured to illuminate the light. It will be appreciated that when the power source is a battery, the operational voltage varies upon usage of the device.
• the controller may be used to internally generate the reference voltage, compare the reference voltage to the operational voltage of the power source, and based on the comparison, permit the light to illuminate.
• the operational voltage from the power source is supplied to controller.
• the controller which includes components that generate a reference voltage, compares the operational voltage supplied to the controller with the reference voltage generated by the controller. If the reference voltage is greater than the operational voltage, the controller outputs an appropriate signal to deliver current to the light, and as a result, illuminates the light.
• the load on the power source by the resistivity of the heating elements causes the voltage of the power source to drop.
• the reference voltage may be selected such that if current is being supplied to the heating elements, the operational voltage measured by the controller will be lower than the reference voltage.
• the light 18a in FIGURE 1 will illuminate, thereby giving the user a visible indication that power is being supplied to the heating elements, and thus, to the heating chamber to melt the stick of adhesive.
• the reference voltage may be selected so that a low power condition of the power source (e.g., a battery that is substantially discharged) will cause the light to illuminate.
• the light may be utilized to indicate when the power source is in need of replacement or a recharge.
• a second reference voltage may be chosen that corresponds to a substantially discharged power source. This may be beneficial since the controller may be programmed or configured to shut off power to the heating element and associated apparatus components when the operational voltage drops below the second reference voltage, thereby protecting power sources, such as rechargeable batteries, that are sensitive to complete discharge.
• FIGURES 11-12 include representative pin-out diagrams and circuitry for connecting the controller in accordance with a preferred embodiment of the present invention.
• FIGURE 11 illustrates possible connections using chip LP2987AIM5X-3.3.
• vb+ is connected to the battery power source, and provides an output constant voltage (3V) as required by the controller chip.
• Dl is a white LED for illuminating the workpiece, as described above.
• FIGURE 12 illustrates representative connections using chip ELAN 78P458 as the controller.
• R2 and R3 are part of a voltage divider for dividing the battery voltage, where pin 4 detects a low battery.
• Pin 9 connects to D3 to generate a light indicating a low battery, and pin 10 generates a light D4 to indicate that a power save operation occurs.
• the negative terminal of the battery is connected to pin 5.
• Pin 18 is connected to a RC coupler (R4 and C5) for generating the clock.
• Pin 11 connects to trigger_detect for a tilt or vibration sensor, as described above. Although not shown, two pins, such as pins 11 and 12, can connect to trigger_detectl and trigger_detect2, for using two sensors.
• Pin 13 is output to a FET to turn on and off the heater.
• pin 3 is connected to thermistorl for measuring the temperature of the nozzle to control when to turn on and off the heater.
• status indicators other than the lights may be utilized by the apparatus.
• a tone-producing mechanism (not shown) that creates an auditory response when a low power condition or a voltage drop is detected may be implemented with the apparatus.
• the apparatus may include a power cord operably connected to the components of the apparatus through appropriate circuitry known to those skilled in the art so that the apparatus may be powered solely by an AC power source, such as a common household power outlet. It will be appreciated that a step down transformer and/or rectifier circuitry may be employed to operate the components of the apparatus from power being supplied from the power outlet.
• the apparatus may include a power cord operably connected to the components of the apparatus through appropriate circuitry known to those skilled in the art so that the apparatus may be powered solely by an exterior DC power source.
• cordless dispensing apparatus can be used for dispensing any materials such as sealants, insulation, any thermoplastic material, or anything else that is dispensed from a carriage or heating chamber.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Coating Apparatus (AREA)

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• 2005
  • 2005-10-12 WO PCT/US2005/036607 patent/WO2006047090A2/en active Application Filing
  • 2005-10-12 EP EP05824068A patent/EP1824777A4/de not_active Withdrawn
  • 2005-10-12 CA CA002584024A patent/CA2584024A1/en not_active Abandoned

Non-Patent Citations (1)

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