Patent Publication Number: US-6220485-B1

Title: Extended piggyback dispensing device with interchangeable application guides

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is based on U.S. Provisional Application 60/130,150 by Chang, Peter J., filed: Apr. 20, 1999, and on U.S. Provisional Patent Application No. 60/119,477 by Chang, Peter J., for his “Adjustable Dispensing Gun Application Guide”, filed: Feb. 9, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to dispensing devices and, more particularly, to an extended dispensing device for application of a bead of caulk or adhesive along hard to reach structural components. The extended dispensing device employs a repairable design with easy to replace components, interchangeable barrels to accept different caulk cartridges, and interchangeable application guides for guiding the application of a bead of caulk or adhesive along trusses, joists and other structural components. 
     2. Description of the Background 
     There are many types of conventional caulk guns all used to dispense a variety of fluid compounds including urethane, vinyl, polyester, epoxy and other plastics or resins. Some of these caulk guns are specially adapted for a particular purpose. One example of a specialty caulk gun is the extended gun that is commonly used in the roofing and flooring context. Extended caulk guns have a barrel, nozzle and cartridge that are separated from the trigger and driving mechanism by an elongated extension, thereby enabling operation of the gun at a distance from where the bead of caulk is applied. This allows an extended reach when compound must be applied to remote areas, such as overhead joists or trusses. Extended caulk guns provide great utility to the flooring and roofing industry. However, different flooring or roofing jobs present different requirements, and extended guns offer very little flexibility. For instance, a larger quart-size cartridge should be used for a longer run job to save costs and avoid frequent cartridge replacement. On the other hand, a smaller {fraction (1/10)}th gallon cartridge should be used for short run jobs. Otherwise, the unused portion of the cartridge goes to waste. Conventional extended guns are made to accommodate either the typical ¼ gallon cartridges or {fraction (1/10)}th gallon cartridges, but not both. Since the extended caulk guns are specialty items, they are relatively expensive to purchase and it is impractical to buy two (one for the ¼ gallon cartridge and one for the {fraction (1/10)}th gallon cartridge). The expense of extended guns also promotes a market for replacement and repair parts, but existing extended guns are generally not repairable. They typically use a welded and/or riveted design and make no provision for swapping out worn parts. Accordingly, there remains a demand for a more flexible extended dispensing gun in which parts are interchangeable to facilitate repair, and which is capable of accommodating at least two different-sized cartridges such as the typical ¼ gallon cartridges and {fraction (1/10)}th gallon cartridges. 
     In addition to the above-described expense of extended guns, their length makes them difficult to maneuver because the weight of the caulk cartridge must be supported at the end of the elongate extension. It is known to mount a caulk application guide at the distal end of the barrel underneath the nozzle to support the cartridge and ensure that a bead of caulk is properly applied. For example, U.S. Pat. No. 4,932,565 to Paradiso shows an extended reach caulking gun with an application guide 24 mounted at the distal end (Paradiso FIG. 1). The guide takes the form of a U-shaped member which is screwed or riveted to the underside of the gun at the barrel end. The U-shaped guide is adapted to straddle and ride along a joist or truss thereby helping to apply the compound in a straight line and with improved accuracy. The U-shaped guide assists in applying compound along studs, rafters and other building components that call for the application of compound along a defined path. Unfortunately, the fixed span of the U-shaped guide 24 is only capable of accommodating studs of a particular size. The guide 24 cannot straddle double studs or many other types of components such as window sills or roof seams. While Paradiso &#39;565 goes on to suggests other guide configurations (see FIGS. 5-7) to accommodate other components, these are not interchangeable and the gun cannot be easily adapted for a particular job. 
     Accordingly, there is also a demand for an extended gun having interchangeable guide members, inclusive of an adjustable guide member, to facilitate quick and easy adaptation for different types of jobs and for applying compound along different types of building components. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide an extended piggyback dispensing device that is capable of accommodating at least two different-sized cartridges, such as the typical ¼ gallon cartridges and {fraction (1/10)}th gallon cartridges. The smaller cartridge may be used for short run jobs while the larger cartridge serves for long run jobs, and the ability to change between the two prevents wasted compound. 
     It is another object to provide a variety of improved caulk gun application guide assemblies and a means for attachment of the same to the above-described piggyback dispensing device to instantly adapt the guide for guidance along different types of building components. 
     It is still another object to provide an extended piggy-back feature and interchangeable caulk gun guide assemblies as described above all of which can be readily retrofit to an existing extended caulk gun. 
     It is another object to provide purchasers of the above-described gun with the lasting value of an extremely flexible design that allows effortless repair of worn parts, swapping out of caulk gun guide assemblies, and swapping out of barrels for different-sized cartridges. 
     According to the present invention, the above-described and other objects are accomplished by providing a piggyback dispensing feature for extended dispensing devices. The piggyback feature may be incorporated in any conventional extended dispensing device of the type generally comprising a housing having a downwardly extending handle, an extension bracket attached forwardly of the housing, a barrel assembly attached to the extension bracket opposite the housing, a piston rod slidably supported in the housing and extension bracket and protruding into the barrel assembly. The improvement comprises an interchangeable push-disk piston mounted on the distal end of the piston rod, and a smaller barrel assembly adapted to be seated inside the other larger barrel assembly to accommodate a smaller-sized cartridge. The piggyback barrel assembly makes it possible to use one extended gun for at least two different-sized cartridges, such as the typical ¼ gallon cartridges and {fraction (1/10)}th gallon cartridges. 
     A number of interchangeable/adjustable guide members are also shown for attachment to the dispensing gun to guide the application of a bead of caulk or adhesive along trusses, joists and other structural components. The multiple interchangeable guide members facilitates quick and easy adaptation for different types of jobs and different types of building components. 
     The guide assembles include a quick-change guide assembly that allows a quick-change reversal to accommodate either a single joist or a double joist position. 
     The guide assemblies also include an adjustable guide with opposing legs that are readily adjustable by hand and on-the-fly to accommodate large-width and double-trusses and joists. 
     All of the guide assemblies can be secured to the dispensing gun by a quick-change detent-lock to allow quick reversal or swapping out to accommodate single joist, double joist, and other structural components. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment and certain modifications thereof when taken together with the accompanying drawings in which: 
     FIG. 1 is a perspective view of extended piggyback dispensing device  2  according to one embodiment of the present invention. 
     FIG. 2 is an exploded perspective view of the extended piggyback dispensing device  2  as in FIG.  1 . 
     FIG. 3 is a close-up perspective drawing of the extended piggyback dispensing device  2  with a smaller {fraction (1/10)}th gallon barrel assembly  60  attached inside of the ¼ gallon barrel assembly  50 . 
     FIG. 4 is a close-up perspective view of the {fraction (1/10)}th gallon barrel assembly  60  with dotted lines showing how it is to be seated in the ¼ gallon barrel assembly  50 . 
     FIG. 5 is a front view of the stabilizer bar  64  as shown in FIG.  4 . The stabilizer bar  64  is a strip of metal that straddles the piston rod  3  and is screwed directly to cap  62 . 
     FIG. 6 is a perspective view of the rear housing  10  of the extended piggyback dispensing device  2  which incorporates a hexagonal piston rod  3  having a handle  33  threaded onto the end. 
     FIG. 7 is a side perspective view of optional coupling  82  to join discrete piston rod segments. 
     FIG. 8A is a close-up composite view of the underside of the {fraction (1/10)}th gallon piggyback barrel assembly  60  illustrating by dotted lines how the idle push-disk piston  70  is removably secured. 
     FIG. 8B is a side cross section of the {fraction (1/10)}th gallon piggyback barrel assembly  60  again illustrating how the push-disk piston  70  is secured. 
     FIG. 9 is a front perspective drawing showing the upper guide  113  that comprises opposing legs  113 A and  113 B that are separated and flared outwardly by a sufficient measure to ride along a single joist. 
     FIG. 10 illustrates the spring-loaded ball-detent mechanism  123  mounted in the distal end of the stem  121 . 
     FIG. 11 is a perspective front view of an adjustable caulk gun guide assembly  90  according to the present invention. 
     FIG. 12 is a perspective side view of the adjustable caulk gun guide assembly  90  as in FIG.  11 . 
     FIG. 13 is a perspective view of the adjustable caulk gun guide assembly  90  as in FIG.  12 . 
     FIG. 14 is a perspective view of a guide member  160  that is suited for guiding the nozzle along concrete structures and windows. 
     FIG. 15 is a is a perspective view of a guide member  180  that is better suited for guiding the nozzle along lap-seal roofing. 
     FIG. 16 is a perspective view of a rolling guide member  190  that is suited for guiding the nozzle along all types of surfaces. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a perspective view of extended piggyback dispensing device  2  according to one embodiment of the present invention. 
     The dispensing device  2  is a manual trigger-operated device incorporating a conventional single-direction gripping assembly  19  that is incorporated in a rear housing  10 . Existing dispensing guns employ a number of different gripping assembly configurations and housing styles, including closed-frame housings (as shown) and open-frame housings. All are suitable for use with the present invention. The single-direction gripping assembly  19  urges an elongate piston rod  3  outwardly through an elongate extension bracket  40  and into a larger barrel assembly  50 . In the illustrated embodiment, the larger barrel assembly  50  is sized to accept a conventional ¼ gallon cartridge. 
     FIG. 2 is an exploded perspective view of the extended piggyback dispensing device  2  as in FIG.  1 . An interchangeable push-disk piston  80  is secured to the end of the piston rod  3 , and the interchangeable push-disk piston  80  drives through the cartridge along barrel assembly  50  to exude compound from the nozzle. The illustrated dispensing device  2  is shown with a 2-in-1 back-to-back guide assembly  30  (to be described) that is attached to the front underside of the barrel  50  to guide application of a bead of caulk along structural components. 
     In accordance with the present invention, the interchangeable push-disk piston  80  can be removed from the end of piston rod  3 , and the piston rod  3  withdrawn to the very end of barrel assembly  50 . A smaller barrel assembly can then be inserted inside the larger barrel assembly  50  to accommodate a smaller-sized cartridge. This avoids waste during smaller jobs. 
     The juncture of extended bracket  40  with housing  10  is also shown. Simple hex screw/bolt combinations  43  are used to allow convenient disassembly for replacement of worn or broken parts. A “D” ring  45  is placed on the end of the handle in order to hold the trigger together when loading a new cartridge. To load a cartridge, the trigger can be locked by the “D” ring  45  by sliding the “D” Ring  45  over the tip of the trigger. This enables a new cartridge to be loaded without the piston rod  3  slipping down. The design facilitates complete disassembly and effortless repair of worn parts. The ¼ gallon barrel assembly  50  is removably secured to the extension bracket  40  by hex bolts or the like. The extension bracket  40  may include one (as shown) or two parallely-spaced hollow steel tubes that are held together at both ends by steel plates. A passage is provided through the plate and in one of the steel tubes in order to pass the piston rod  3 . In the case of double tubes, the second tube serves as reinforcement. 
     FIG. 3 is a close-up perspective drawing of the extended piggyback dispensing device  2  with a smaller {fraction (1/10)}th gallon barrel assembly  60  attached inside of the ¼ gallon barrel assembly  50 . This is accomplished by seating the smaller {fraction (1/10)}th gallon barrel assembly  60  inside the ¼ gallon barrel assembly  50 , and then reinserting piston rod  3  through smaller barrel assembly  60 . The distal end of the piston rod  3  is then equipped with a different (smaller) interchangeable push-disk piston  70 . In just a few short moves, the extended dispensing gun  2  is converted for use with one of two different-sized cartridges such as the illustrated ¼ gallon cartridge and {fraction (1/10)}th gallon cartridge. In effect, the {fraction (1/10)}th gallon barrel assembly  60  “piggybacks” inside of the ¼ gallon barrel assembly  50 . Both of the {fraction (1/10)}th gallon barrel assembly  60  and ¼ gallon barrel assembly  50  are half-barrel assemblies for seating appropriately-sized caulk or other fluid compound cartridges. Both of barrel assemblies  50 ,  60  are partially closed at the leading end by retaining walls  51 ,  61 , respectively. The retaining walls  51 ,  61  are defined by a downward yoke for seating the plastic tips of the respective {fraction (1/10)}th gallon and ¼ gallon cartridges. Both barrel assemblies  50 ,  60  are closed at the other ends by caps  52 ,  62 , respectively, both caps  52 ,  62  being annular steel members with centrally-aligned apertures to pass the piston rod  3 . 
     The two different-sized barrel assemblies  50 ,  60  are suited for different-sized caulking jobs. For instance, the smaller cartridge may be used for short run jobs while the larger cartridge serves for long run jobs. 
     Just as the size of the job may vary, so to might the structural requirements. For example, either single joists and trusses or double joists and trusses may be used in the construction of dwellings. To accommodate single joists and trusses as well as double joists and trusses, a 2-in-1 back-to-back guide assembly  30  is attached to the front underside of the barrel  50 . The end cap  52  of the larger barrel assembly  50  is removably secured to one end plate of the extension bracket  40  (with the piston rod  3  protruding inside the larger barrel assembly  50 ), while the other end plate of the extension bracket  40  is screwed directly to the main housing  10 . 
     FIG. 4 is a close-up perspective view of the {fraction (1/10)}th gallon barrel assembly  60  with dotted lines showing how it is to be seated in the ¼ gallon barrel assembly  50 . The {fraction (1/10)}th gallon barrel assembly  60  is laterally secured inside of the ¼ gallon barrel assembly  50  by a stabilizer bar  64 . 
     FIG. 5 is a front view of the stabilizer bar  64  as shown in FIG.  4 . The stabilizer bar  64  is a strip of metal that straddles the piston rod  3  and is screwed directly to cap  62 . The outward ends of the stabilizer bar  64  conform to the curvature of the barrel assembly  50  and function to line up the smaller barrel assembly  60  within the larger barrel assembly  50 . This ensures that the piston rod  3  will pass straight through a tubular extension  66  (seen in FIG.  4 ). The tubular extension  66  is anchored to the backside of the stabilizer bar  64 , and this imparts a secure longitudinal seating of the smaller barrel assembly  60 . The tubular extension  66  provides a footing against the end cap  52 , and is equipped with a spring-loaded collar  68  for biasing the smaller barrel assembly  60  against the front of the larger barrel assembly  60 . Piston rod  3  will pass straight through tubular extension  66  and into the smaller barrel assembly  60 . 
     FIG. 6 is a perspective view of the rear housing  10  of the extended piggyback dispensing device  2  which incorporates a hexagonal piston rod  3  having a handle  33  threaded onto the end. Either a circular, hexagonal or square piston rod may be used as will be appreciated by those skilled in the art. Moreover, discrete piston rod segments may be used as will be described to simplify repair and replacement. 
     FIG. 7 is a side perspective view of optional coupling  82  to join discrete piston rod segments. The preferred overall rod  3  length is approximately 43″. A segmented piston rod feature allows the use of normal (less expensive) piston rod segments to manufacture the extended dispensing device  2 . The piston rod  3  can be formed in as many segments as desired, and all of the segments can be coupled together via couplings  82  with threaded bore holes at each end. In each case, the segments of piston rod  3  are likewise threaded at the ends for screw insertion into couplings  82 . Hex segments  3 A can be joined to round segments  3 B or to square segments as desired. This segmented design reduces manufacturing costs. In addition, when a rod segment wears out it is much easier and less expensive to replace. Moreover, the segmented configuration also allows the reversal of segments within the gun  2  in order to prolong the life of the piston rod. 
     FIG. 8A is a close-up composite view of the underside of the {fraction (1/10)}th gallon piggyback barrel assembly  60  illustrating by dotted lines how the idle push-disk piston  70  is removably secured. The push-disk piston  70  (and identical but larger diameter push-disk piston  80 ) are both conventional cupped pistons that are sized appropriately for the intended cartridge. Both are provided with a centrally-threaded coupling  72  to allow screw attachment and removal to/from the threaded end of the piston rod  3 . 
     FIG. 8B is a side cross section of the {fraction (1/10)}th gallon piggyback barrel assembly  60  again illustrating how the push-disk piston  70  is secured. As shown in FIG. 8B a threaded stud  62  projects downwardly from the underside of the {fraction (1/10)}th gallon piggyback barrel assembly  60 . This allows the user to screw on the idle push-disk piston  70  when not in use, thereby avoiding lost parts. The threaded stud  62  may be screwed into the underside of the {fraction (1/10)}th gallon piggyback barrel assembly  60  by more or less to thereby vary the extent by which it projects downwardly from the barrel assembly  60 . Given this adjustability, stud  62  serves the dual purpose of acting as an adjustable vertical spacer between the ¼ gallon barrel assembly  50  and the {fraction (1/10)}th gallon piggyback barrel assembly  60 . 
     The operation of swapping out barrel assemblies will now be described with reference to all of FIGS. 1-8. Interchangeable push-disk piston  80  is removed from the end of piston rod  3 . The piston rod  3  is withdrawn all the way to the end of the ¼ gallon barrel assembly  50 . The smaller {fraction (1/10)}th gallon barrel assembly  60  is seated inside the ¼ barrel assembly  50 , and the spring-loaded collar  68  of the tubular extension  66  is aligned with the hole in the end cap  52 . The user pushes the smaller {fraction (1/10)}th gallon barrel assembly  60  down to ensure that it is seated on the bottom of the ¼ barrel  50 . The front walls of the barrel assemblies  50 ,  60  should be aligned, and then the smaller push-disk piston  70  is screwed to the end of piston rod  3 . 
     The above-described design provides an extended piggyback dispensing capable of accommodating at least two different-sized cartridges, including standard ¼ gallon cartridges and {fraction (1/10)}th gallon cartridges. All parts are 100% replaceable, and this has not been possible with any comparable unit on the market. The advantages are as follows: 1) at the price of one gun, the user can have the functionality of two guns; 2) the device saves carrying space, either in toolbox or in a truck; 3) the user need only carry one extended gun on a ladder to the roof or any job site, rather than two unwieldy guns; 4) savings in compound due to not being limited to a larger cartridge. 
     The full ability to adapt the foregoing dispensing device to a variety of different jobs calls for a variety of interchangeable and/or adjustable guide members for applying compound along different types of building components. One useful guide member is the 2-in-1 back-to-back guide assembly  30  that has been shown attached to the front underside of the barrel  50 . 
     FIGS. 9-11 further illustrate the 2-in-1 back-to-back guide assembly  30  as shown in the foregoing description. The 2-in-1 back-to-back guide assembly  30  offers the convenience of a quick-flip changeover to accommodate either a single joist of a double joist. 
     FIG. 9 is a front perspective drawing showing the upper guide  113  that comprises opposing legs  113 A and  113 B that are separated and flared outwardly by a sufficient measure to ride along a single joist. Also shown is the back-to-back lower guide  115  that comprises opposing legs  115 A and  115 B that are separated and flared outwardly by a sufficient measure to ride along a double joist. The upper guide  113  may be formed from a unitary steel member with bent legs  113 A and  113 B. Likewise, the lower guide  115  may be formed from a unitary steel member with bent legs  115 A and  115 B. Both the upper and lower guides  113 ,  115  are mounted (by welding or the like) to opposing sides of a stem  121  comprised of a length of hexagonal or rectangular steel rod. 
     As shown in FIG. 10, a spring-loaded ball-detent mechanism  123  is mounted in the distal end of the stem  121 . Ball-detent mechanism  123  includes a spring mounted inside the steel rod of stem  121  in a known manner, the spring biasing a ball bearing against a small bore hole in the side of the steel rod. The ball bearing protrudes outward slightly from stem  121 . A mating receptacle  35  is mounted on the front end of the caulk gun on the underside of the ¼ gallon barrel assembly  50 , and this is equipped with a bore hole  36  that can be slidably aligned with the ball bearing  27 . This way, as shown by dotted lines in FIG. 10, the 2-in-1 back-to-back guide assembly  30  is inserted by its undercarriage  21  into the mating receptacle  35  on the front end of the caulk gun, and the ball bearing  27  becomes seated in the bore hole  36  of the receptacle  35 , thereby locking the 2-in-1 back-to-back guide assembly  30  in position. 
     In operation, the guide assembly  30  straddles the intended construction component (such as a joist, truss, etc.) and rides along the construction component as the user applies a uniform continuous bead of caulk. The straddled legs  113 A and  113 B permit rocking of the guide assembly  30  and gun maneuver the nozzle as desired, yet prevent the guide assembly  30  from being dislodged from the construction component. The 2-in-1 back-to-back guide assembly  30  can be quickly and conveniently snapped out of position, reversed, and snapped back into place to accommodate either a single joist or a double joist. 
     As an alternative to the 2-in-1 back-to-back guide assembly  3 , FIG. 11 is a perspective front view of an adjustable caulk gun guide assembly  90  according to the present invention. Guide assembly  90  generally comprises a T-shaped undercarriage  114 , a pair of adjustable downwardly extending legs  110 A and  1103 B, a pair of wing nut/screw combinations  112 A and  112 B for attaching the respective legs to the T-shaped bracket  114 , and a forwardly-disposed guide member  120 . The guide assembly  90  is removably attached beneath the barrel of the caulk gun with legs  110 A and  110 B protruding downwardly and guide member  120  protruding forwardly. Attachment of the guide assembly  90  beneath the barrel of the caulk gun may be accomplished with the a locking receptacle configuration as described above, or by rivets, screws, or any other known manner. 
     FIG. 12 is a perspective side view and FIG. 13 is a perspective top view of the adjustable caulk gun guide assembly  90  as in FIG.  11 . The T-shaped undercarriage  114  may include a pair of bore-holes  132  through the stem portion for screw-attachment to the underside of the caulk gun barrel. The outwardly extended arms of the T-shaped undercarriage  114  are defined by opposing oblong slots  134 A and  134 B. Slots  134 A and  134 B are adapted to pass the screws of the respective wing nut/screw combinations  112 A and  112 B. The wing nut/screw combinations  112 A and  112 B are also anchored to the legs  110 A and  110 B, and given this configuration the legs can be adjusted lengthwise along the outwardly extended arms of the T-shaped undercarriage  114  within opposing slots  134 A and  134 B. Thus, the legs  110 A and  110 B can be adjusted to a desired spacing to accommodate trusses and/or joists of different dimensions. Specifically, given a 1″ slot  134 A and  134 B as shown, the guide  90  can be conveniently adjusted on-the-fly to straddle a standard 1.5″ single and 3.5″ double floor trusses, joists, etc. 
     To further facilitate adjustment, the legs  110 A and  110 B are formed as mirror-opposite members each protruding downwardly from a horizontal section that slidably abuts the underside of the T-shaped undercarriage  114 . The opposing legs  110 A and  110 B are flared outwardly. To maintain proper alignment of the legs  110 A and  110 B, each is formed with an upturned flange  111 A and  111 B that protrudes upward directly in front of the T-shaped undercarriage  114 . In addition to maintaining proper alignment of the legs  110 A and  110 B, the flanges  111 A and  111 B lock the legs  110 A and  110 B in position when the wing nuts  112 A and  112 B are tightened. As can be seen, the T-shaped undercarriage  114  is preferably formed with an angle to extend the forward section downwardly from the caulk gun. 
     FIGS. 14-16 are perspective drawings of three additional guide members  160 ,  180  and  190  that are interchangeable with the guide assembly  90 , each being designed to follow a different structural component. Specifically, FIG. 14 is a perspective view of a guide member  160  that is suited for guiding the nozzle along concrete structures and windows. The guide member  160  is formed from a steel section as a forwardly projecting tongue that angles downward in advance of the nozzle and along the component or surface to which compound is being applied. Concrete and window applications typically provide good sliding surfaces and require exacting precision to apply a watertight seals. For this reason the distal end of the guide member reaches a sharp apex. Again, the forwardly projecting guide member  160  helps to steer the gun when it is necessary to follow a joint, line or roofing seam, said member  160  projecting there against to direct application of the bead of caulk. 
     FIG. 15 is a is a perspective view of a guide member  180  that is better suited for guiding the nozzle along lap-seal roofing. The guide member  180  is formed from a steel section as a forwardly projecting tong that angles downward in advance of the nozzle and along the component or surface to which compound is being applied. Roofing work typically involves rough sliding surfaces, and for this reason the distal end of the guide member is slightly concave and the periphery is rounded to facilitate sliding. The forwardly projecting guide member  180  helps to steer the gun when it is necessary to follow a joint, line or seam, said member  180  projecting there against to direct application of the bead of caulk. 
     FIG. 16 is a perspective view of a rolling guide member  190  that is suited for guiding the nozzle along all types of surfaces. The guide member  190  is again formed from a steel bracket  128  that projects forwardly and downwardly in advance of the nozzle to opposing struts. A roller  126  is rotatably supported on an axle  127  that is supported between the struts of bracket  128 . The roller  126  tends to maintain a linear course as it rolls along a flat surface thereby helping to steer the gun to direct application of the bead of caulk. 
     All of the guide members  90 ,  160 ,  180  and  190  of FIGS. 14-16 may be attached to the underside of the dispensing gun by conventional anchoring devices such as thumb-screws through aligned bore holes  132 ,  162 ,  182  and  192  and into the underside of the dispensing gun. Alternatively, the guide members  90 ,  160 ,  180  and  190  may be adapted to fit a mating receptacle mounted on the front end of the caulk gun as described in previous embodiments, inclusive of a locking detent mechanism to secure the guide member in position. 
     All of the above-described guide assemblies with multiple interchangeable guide members facilitates quick and easy adaptation for different types of jobs and different types of building components. This flexibility eliminates the need for multiple dedicated guides and reduces the burden of carrying the same and/or the risk of lost parts. Moreover, all of the guides can be readily retrofit to an existing caulk gun and readily removed for use of the gun without the guides. 
     Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications thereto may obviously occur to those skilled in the art upon becoming familiar with said underlying concept. For example, although the invention is shown in the context of a conventional closed-frame half-barrel extended dispensing gun, it should be appreciated that the invention is equally suited for open-frame guns and/or with parallel frame guns (in vertical or horizontal format), and that the sizes of the barrel assemblies and cartridges may be easily varied. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth herein.