Patent Publication Number: US-6981621-B2

Title: Caulking gun

Description:
This application is a 371 of PCT/IL03/00071 Jan. 29, 2003 which claims benefit of 60/352,238 Jan. 29, 2002. 

   FIELD OF THE INVENTION 
   The present invention relates to dispensing devices and more particularly to an open-framed cartridge caulking gun having a push-rod formed by two interlocking chains. 
   BACKGROUND OF THE INVENTION 
   Caulk is a waterproofing material used by building contractors and homeowners for sealing windows, doors and bathtubs. 
   Caulk is most conveniently dispensed and applied using caulking guns, to which are fitted a plastic or cardboard tube containing caulk. 
   Two main types of caulking guns are known. The first is the bulk dispensing gun, which is a complete unit containing a closed cylindrical chamber with nozzle and actuating means. The second is the open framed cartridge gun, in which the gun itself and a disposable cartridge containing caulk comprise separate elements. 
   The open-framed cartridge gun typically comprises a cradle to receive a cartridge containing caulk, one end of the cartridge having a dispensing nozzle. A piston is provided within the cartridge. Caulk is dispensed by exerting pressure on a trigger of a pistol-grip mechanism, which actuates a push rod having a thrust disk at its front end. Pressure exerted by the thrust disk against the caulk cartridge piston forces caulking material out of the cartridge nozzle. 
   Many variations of the open-framed cartridge gun have been described in the art. In all of these, the push rod is at least as long as the cartridge, plus the distance the push rod must travel through the pistol-grip mechanism in order to be able to urge the thrust disk along the entire length of the cartridge. In addition, a small segment of the push rod must remain exposed after the cartridge has been depleted so that the exposed segment of the push rod can be grasped by hand and retracted to the starting position. The total length is further increased by the nozzle of the cartridge when full, resulting in a relatively long caulking gun. Such a device is awkward to handle and cannot easily fit into tight spaces such as cupboards, closets, behind doors etc. 
   In existing open-framed cartridge guns the cartridge is inserted by first retracting the push rod, then manually manipulating the cartridge into place. The cartridge is released by retracting the push rod while simultaneously pressing a release lever or button. These manipulations are awkward and time-consuming. 
   Therefore, it would be desirable to provide a cartridge caulking gun which is shorter and easier to manipulate than the prior art devices, and in which loading and removal of cartridges is simplified. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is an object of the present invention to overcome the disadvantages of the prior art and provide a relatively short caulking gun, which is easy to manipulate. 
   In accordance with a preferred embodiment of the present invention, there is provided a caulking gun formed entirely of plastic, which eliminates the problems of rusting and general wear and tear associated with prior art devices. The caulking gun comprises a barrel having an open framework for receiving and cradling a caulk cartridge provided with an extrusion nozzle at one end. A drive mechanism is provided to forwardly advance a chain arrangement comprising two separately coiled chains, each composed of a series of individual hollow links connected in pivotable fashion one to another. The shape of the individual chain links of the two chains enable them to be interlocked as one parallel chain, forming a push-rod to compress the caulk cartridge piston, to empty it of material. The coiled chains enable the chain arrangement to bend 180 degrees, so that the overall caulking gun length is reduced by eliminating the backward protruding rod of the standard device. 
   According to a preferred embodiment, there is provided a caulking gun comprising an elongated body, a pair of chains situated within the elongated body in coiled fashion, the chains being fixedly interlocked one to another at a front end thereof, a coiled portion of the chains being reversibly interlockable one to another to form a push-rod when extended, a disk-shaped element attached to the push-rod, a self-contained driving mechanism for graduated extension of the coiled portion of the pair of chains in parallel interlocked fashion, forming the push-rod, and a release mechanism for restoring the pair of parallel chains to their fully retracted, coiled position, such that by repeated activation of the driving mechanism, the coiled chains are brought into interlocking contact one with the other, increasing the length of the push-rod, thereby carrying the disk element forward against a caulk cartridge inserted within the elongated body, causing extrusion of material contained in the cartridge. 
   A feature of the present invention is that the push-rod of the caulking gun is formed by interlocking of two parallel chains. 
   An advantage of the present invention is that the caulking gun is shorter than conventional devices and therefore easier to manipulate. 
   A further advantage of the present invention is that loading and removal of the cartridge of the caulking gun is rapid and simple. 
   A further advantage of the present invention is that the device is extremely lightweight. 
   A further advantage of the present invention is that the device requires less storage space than prior art devices. 
   A further advantage of the present invention is that the device is formed entirely of plastic, therefore no rusting occurs. 
   A further advantage of the present invention is that it does not include a protruding push-rod, and is therefore safer to use than conventional devices. 
   A further advantage of the present invention is that the operating mechanism is closed, eliminating problems of exposure to dirt and other harmful matter. 
   A further advantage of the present invention is that the device is operable with one hand. 
   A further advantage of the present invention is that a caulking cartridge may be quickly inserted and removed from the device by operation of a slidable locking mechanism. 
   Additional features and advantages of the invention will become apparent from the following drawings and description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the invention with regard to the embodiments thereof, reference is made to the accompanying drawings, in which like numerals designate corresponding sections or elements throughout, and in which: 
       FIG. 1  is a side view of a caulking gun constructed and operated in accordance with the principles of the present invention; 
       FIG. 2   a  is a perspective view of the caulking gun of  FIG. 1 ; 
       FIG. 2   b  is a perspective view of an alternative embodiment of the caulking gun of  FIG. 1 ; 
       FIG. 3  is an exploded view of the caulking gun; 
       FIG. 4  is a cross-sectional side view of the caulking gun; and 
       FIG. 5  is a cross-sectional top view of the caulking gun. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Reference is now made to  FIGS. 1 ,  2   a  and  2   b , which illustrate the caulking gun  10  of the present invention. 
   Caulking gun  10  comprises a barrel  12 , having a rear edge  13 , a handle  14  extending essentially perpendicular to barrel  12 , and a trigger  16  positioned within handle  14  for operating a drive mechanism  26  (shown in  FIGS. 3–5 ). A removable closure  19  is attached to wall  13 . 
   Caulking gun  10  is formed entirely of plastic such as fiberglass-reinforced polypropylene, fiberglass-reinforced polycarbonate or fiberglass-reinforced nylon. Use of plastic eliminates the problems of rusting and general wear and tear associated with prior art devices. 
   Barrel  12  comprises a slightly flattened tube having an open framework for receiving and cradling a caulk cartridge or canister (not shown) provided with an extrusion nozzle at one end. 
   The forward end of barrel  12  is provided with an open end  18  through which the nozzle of the caulk cartridge is able to protrude. A pair of L-shaped locking clips  20  are pivotally mounted one on either side of open end  18 , such that when clips  20  are in the locked position, a recess  24  is formed between flange  21  of clip  20  and an internal protrusion  22 , situated perpendicular to the axis of barrel  12 . 
   With clips  20  in the open position, the caulk cartridge (not shown) is inserted into open end  18  with extrusion nozzle directed outwards, until its rim contacts internal protrusion  22 . Clip  20  is then closed such that the cartridge rim is firmly held in position in barrel  12  within recess  24 . 
   In an alternative embodiment, shown in  FIG. 2   b , a contoured ring  23  is positioned around open end  18  of barrel  12 , enclosing clips  20  to prevent accidental opening of clips  20 . Ring  23  is fixed in position by engaging pin  25 , which may be released to enable ring  23  to be slidingly displaced away from the direction of open end  18  (see arrow “A”), thereby releasing clips  20 . This enables a caulk cartridge (not shown) to be rapidly loaded into and removed from barrel  12 . 
   Caulking gun  10  also includes a drive mechanism  26  and release mechanism  27 , described in detail below, which are situated within barrel  12  and activated by trigger  16  and release button  17 , respectively. Trigger  16  and release button  17  are both operable with the same hand, such that upon completion of caulk extrusion, release button  17  may be depressed to release residual pressure within the cartridge, thereby preventing dripping of excess caulk. 
   Handle  14  is an open frame comprising a horizontal lower surface  32  attached to a substantially perpendicular front-facing surface  34 , which connects lower surface  32  to barrel  12 . Trigger  16  is positioned within the hollow rear section  36  of handle  14 . Rear section  36  A plurality of short, raised, strips  38  are formed along the length of sides  36  to enable a non-slip pistol grip. 
   Referring now to  FIGS. 3 to 5 , the drive mechanism  26  and release mechanism  27  are shown. 
   Rear surface  37  of handle  14  extends upwards into barrel  12 , forming an edge  37   a . Drive mechanism  26  is positioned forward of edge  37   a  and release mechanism  27  is pivotally attached to a flange  63  extending backwards from edge  37   a.    
   Drive mechanism  26  comprises a thrust disk  28  positioned at the forward end of a chain arrangement  30 , a biasing spring  56  positioned over chain arrangement against a jam plate  58 , seated in compartment  59 . Jam plate  58  is formed with a window  60  through which chain  30  passes. Drive mechanism  26  is actuated by trigger  16 , formed with a tapering lower end and a push tab  70  at its upper end. 
   Chain arrangement  30  comprises two separate chains  30   a ,  30   b , each composed of a series of individual hollow links  40  connected in pivotable fashion one to another. As seen in  FIG. 5 , each link  40   a  of chain  30   a  is provided with a tab  42  and a notch  44 , insertable within a complementary notch  44  formed on each link  40   b  of parallel chain  30   b . Adjacent links  40  are each pivotable about pin  46 , which enables each chain  30   a ,  30   b  of chain arrangement  30  to bend 180 degrees, as shown in  FIG. 3 . 
   Barrel  12  is further provided with two parallel elongated channels  48   a ,  48   b  ( FIG. 5 ), which run adjacent to the inner wall of barrel  12 , each having a width sufficient to enable seating of links  40  of a respective one of chains  30   a ,  30   b  therewithin. Channels  48   a ,  48   b  terminate at internal protrusion  22 , described above with reference to  FIGS. 2   a  and  2   b.    
   The end of barrel  12  towards which trigger  16  is situated is provided with a pair of circular guides  50   a ,  50   b  around which pass links  40  of chains  30   a  and  30   b  respectively. 
   Guides  50   a  and  50   b  are spaced at a suitable distance one from the other such that when chains  30   a ,  30   b  pass around guides  50   a ,  50   b  respectively, the two chains  30   a ,  30   b  are forced into contact one with the other in the region between the two guides  50   a ,  50   b.    
   Links  40  of chain  30   a  are each formed with a side protrusion  42 , extending towards parallel chain  30   a , and insertable within a complementary recess  4   s   4  formed on the side surface of each link  40  of chain  30   b  facing chain  30   a , such that by forcing the chains into contact, they become firmly interlocked as one. 
   This firm interlock between chains  30   a ,  30   b , forms a solid, inflexible rod which serves as a push-rod  80  for driving thrust disk  28  forward. 
   In operation, when trigger  16  is depressed in the direction of rear section  36  of handle  14 , push tab  70  of trigger  16  is pushed forward against a lower edge of jam plate  58 , causing jam plate  58  to slant backwards from an axis perpendicular to that of chain  30 , and to pivot within channel  64 . Due to the inclined orientation of jam plate  58  on chain  30 , links  40  of chain  30  become engaged with an edge of window  60 . Thus, as jam plate  58  moves, chain  30  moves together with it, advancing in a forward direction, against the action of spring  56 . Upon release of trigger  16 , jam plate  58  returns to a vertical orientation by the action of spring  56 , releasing chain  30 . Jam plate  58  returns to its original position while chain  30  remains in the position to which it has been advanced by operation of trigger  16 . 
   Once the caulking cartridge has been used, whether it has been emptied or if it is to be stored for re-usage, it may be removed easily from caulking gun  10  by releasing locking clips  20 . 
   Release mechanism  27  comprises a locking plate  62 , pivotally attached at its upper end  72  to flange  63 . Locking plate  62  is formed with a window  74  and is positioned so as to slant backwards from attachment point at upper end  72 . Chain  30  is therefore held firmly by the edges of window  74  of locking plate  62 , preventing chain  30  from retracting and returning to its original position after release of trigger  16 . Upon exertion of pressure on release button  17 , the lower end of locking plate  62  of release mechanism  27  moves forwards, causing locking plate  62  to straighten vertically from the inclined angle, resulting in disengagement of chain  30 . Chain  30  may then be manually retracted by exertion of pressure upon thrust disk  28 . 
   The entire drive mechanism  26  is enclosed within a suitably shaped, removable, snap-on covering  19  which provides protection from exposure to dust and other airborne particles, oil, water etc. which could decrease the efficiency of the mechanism. 
   The present invention therefore provides a caulking gun  10  in which the push-rod  80  is formed by two retractable, interlocking chains  30   a–b , enabling the gun to be designed with significantly reduced length in comparison with standard caulking guns, based on use of a self-contained driving mechanism. The resulting gun is simple to use and is easy to manipulate in small, confined spaces. Less storage space is also required. The absence of a protruding push-rod renders the caulking gun  10  safer to use. 
   The plastic composition of caulking gun  10  eliminates the problem of rusting which is common in conventional caulking guns and provides and extremely lightweight device. Furthermore, plastic is less susceptible to general wear and tear which occur as a result of repeated use. 
   Having described the invention with regard to certain specific embodiments thereof, it is to be understood that the description is not meant as a limitation, since further modifications will now suggest themselves to those skilled in the art, and it is intended to cover such modifications as fall within the scope of the appended claims.