| US4949881A | 1990-08-21 | |||
| US7520408B1 | 2009-04-21 | |||
| US5236269A | 1993-08-17 | |||
| US6558059B1 | 2003-05-06 | |||
| US20060191957A1 | 2006-08-31 |
| I claim: 1 . A hot melt glue gun comprising a glue gun housing, a melt chamber mounted in said glue gun housing, a glue stick housing for receiving a glue stick and mounted in said glue gun housing for movement toward and away from said melt chamber, and a gripper, said gripper being pivotally mounted on said glue stick housing and comprising a gripper point that engages a glue stick when pivoted in one direction and disengages from said glue stick when pivoted in an opposite direction and wherein said gripper comprises a palm feed handle positioned to be engaged by the palm of a user to pivot said gripper point in said one direction and advance said glue stick housing toward said melt chamber and wherein said glue gun housing forms a handle portion with a cavity to receive a battery and said handle portion includes a door pivotally attached to said glue gun housing to provide access to said cavity. 2. A hot melt glue gun according to claim 1 wherein said door includes an electrical contact that engages a mating electrical contact in said glue gun housing when said door is in a closed position. 3. A hot melt glue gun according to claim 2 wherein said door is forms a front part of said handle portion and said palm feed handle is on an opposite side of said handle portion. 4. A hot melt glue gun according to claim 1 where said door forms a bottom portion of said handle portion. 5. A hot melt glue gun according to claim 4 further comprising a flat formed spring on said door to urge a battery into said cavity and electrically connect a terminal of said battery to a control board. 5 |
Technical Field
[001] This invention relates to the art of hand-held hot melt glue guns. In particular the design of the invention is particularly advantageous in battery-powered glue guns.
Background
[002] With continued improvements in battery technology, users are interested in the flexibility and ease-of-use provided by battery-powered items, such as hand tools, lawn mowers, and the like. Providing a battery to power a glue gun presents challenges in the placement of the battery in a small hand-held article the size of a glue gun. As well, a battery for a glue gun must itself provide power adequate to melt glue for the time period of an expected use, and the physical structure of the glue gun must facilitate replacement of a spent battery with one having a full charge.
Summary of the Invention
[003] In accordance with the invention, a hand-held glue gun preferably uses a palmfeed mechanism to advance a glue stick into a melt chamber. This design allows the interior space of the handle portion of the glue gun to form a cavity large enough to receive a rechargeable battery. The glue gun is also provided with a door that provides access to the cavity for removal of a spent battery and insertion of a charged battery. [004] In one embodiment, the battery-access door forms the front of the handle portion of the glue gun and is pivotally mounted at a lower portion to pivot away from the glue gun handle to allow access to the battery. In another embodiment, the door forms the bottom of the handle portion, which allows removal and replacement of a battery from the bottom of the handle portion of the glue gun.
Brief Description of the Drawings
[005] Figure 1 is a side view of a battery-powered glue gun in accordance with the invention with the right half of the glue-gun housing removed.
[006] Figure 2 is a side view of a second embodiment of a battery-powered glue gun in accordance with the invention with the right half of the glue-gun housing removed.
[007] Figure 2a is a side view of the flat-formed contact spring shown in figure 2. [008] Figure 3 is a side view of the bottom portion of the glue gun of figure 2.
Detailed Description of the Invention
[009] With reference to figure 1 , a glue gun includes a housing 2, which supports a melt chamber 38. A glue stick advancement housing 6 is mounted to the glue gun housing 2 for sliding movement toward and away from the melt chamber. A glue stick gripper 8 is pivotally mounted to the housing 6 to engage a glue stick (not shown) as known in the art. A link 12 extends from an upper portion 14 of a palm handle 16, which is pivotally attached to the housing 2 at 52.
[0010] The handle portion 4 is hollow to allow a battery 36 to be located in the handle portion 4. The palm-feed mechanism is used to advantage here because it provides space for the battery inside the housing without compromising the effectiveness of the movable gripper housing 6 and glue gripper 8.
[0011] In the embodiment shown in figure 1 the front portion of the handle portion 4 comprises a front door 16. The front door is pivotally attached to the remainder of the handle portion at pivotal connection 18 to allow the door 16 to rotate forwardly to provide a user access to the battery 36 for removal of a spent battery and replacement with a fully charged one. A snap catch 20 is provided in the handle portion 4 to engage a mating part (not shown) on the door 16 to hold it in a closed position when the door is closed.
[0012] The upper part of the door forms a shelf 22 that carries a first battery contact 24 for engaging an upper terminal of the battery 36. The first battery contact includes an upper spring section for engaging the upper terminal of the battery and wraps over the shelf to provide a protruding end 26 that engages an upper electrical contact 28 in the glue gun housing 2 when the door is closed.
[0013] A lower portion of the door 16 includes a lower shelf 30 that supports the battery and includes a second battery contact 32 that wraps over the lower shelf 30 so that the second battery contact 32 engages a lower electrical contact 35 in the housing when the door is closed. It will be appreciated that the door 16 and the palm feed handle 34 are preferably on opposite sides of the handle portion 4, whereby a user naturally requires the door to be closed before a glue stick can be advanced.
[0014] Figure 2 shows a second embodiment of the invention. In this embodiment, a palm handle 34 is provided. A battery 36 is housed in the handle portion 4. Preferably, the battery is rechargeable and can be removed from the glue gun for recharging. As in the embodiment of figure 1 a second, fully charged, battery can be placed in the handle while the first battery is being recharged. Battery 36 is preferably an 18650 lithium-ion unprotected battery.
[0015] With reference to the embodiments of figures 1 and 2, a melt chamber 38 is heated by a PTC element 40 secured to the melt chamber by known means and insulated therefrom electrically by a Kapton sheet. The PTC element is connected to a 5A control board 42, which is connected to the battery, to provide the PTC element with electrical current to heat the melt chamber 38. Control board 42 is preferably a lithium- ion battery protection board that prevents short-circuiting, excessive current, low voltage, and other potentially dangerous conditions for the high energy 18650 unprotected battery.
[0016] The battery 36 is held in the handle portion between a positive terminal button 44 and a spring contact 46. The positive terminal button is connected to the battery protection board by a conductor (not shown), and the battery protection board 42 is connected to the negative end of the battery by a flat-formed contact spring 46 and a ground contact wire 48. Contact spring 46 may be called a four-slide part based on the equipment it is made with. It is preferably a flat piece of spring steel or brass that is about .010" thick x .25" wide which is formed into a spring-like pattern shown in side view in figure 2a.
[0017] A bottom door 50 is provided to allow removal and replacement of the battery for recharging. The door is preferably pivotally attached to the handle portion, as by a pivot connection 52. Door 50 includes a molded-in snap hook 53 opposite the pivotal connection 52 that engages with a matched undercut opening molded into the handle to hold door 50 closed against the spring force applied by the flat formed spring 46. A user can open the door 50 by applying pressure on the exterior of the hook 53 to disengage it. [0018] The flat formed spring contact 46 is configured to provide two functions simultaneously when the door 50 is closed. The top part of the contact spring 46 engages the bottom of the battery with sufficient force to make good electrical contact. The contact spring 46 is also provided with an extension arm 54, also made of elastic, electrically conductive material that connects the negative end of the battery to the ground contact wire 48 when the door 50 is closed. Thus, the spring contact 46 is engages the bottom of the battery and the ground contact wire by an upward spring force to connect the negative end of the battery to the ground contact wire and also to the control board 42.
[0019] With reference to figure 2a, the preferred contact spring 46 is shaped to provide several folded layers to provide a spring force and a rounded end 56 on the upper layer to engage the bottom of battery 36 when the battery is in an operative position in the handle 4 and the door 50 is closed. The spring is preferably a flat, folded spring configured to provide a rounded upper end 56 that engages the battery. The bottom of the spring is mounted on the door 50 such that the rounded end 56 is spaced from a centerline 58 of the spring such that engagement between the rounded end 56 and the battery applies an asymmetric force (torque) on the spring causing the arm 54 to rotate upward as shown by arrow 60 to contact the lower portion of the ground contact wire 48 securely and complete the connection to the battery protector board 42.
[0020] Figure 3 shows the bottom door 50 of the glue gun shown in figure 2. The door includes a rib 74 that engages the bottom of the battery 36 to urge it upward to maintain good contact between the upper terminal of the battery and the contact pin 62. The contact spring 46 as shown in figure 2a can be used in this embodiment also.
[0021] Modifications within the scope of the appended claims will be apparent to those of skill in the art.