Patent Abstract:
A reusable or disposable adhesive dispensing cartridge including a housing for containing a quantity of adhesive, an adhesive delivery element connected to the housing and having a plurality teeth spaced apart by recesses and a plate movably mounted in the housing to force adhesive from the housing and through flow passages that extend between the interior of the housing and the recesses. An adhesive applicator includes a cartridge holder for retaining the cartridge and a movable drive element coupled to the cartridge plate to move the plate in a direction to force adhesive out of the housing and through the flow passages.

Full Description:
The present application is a continuation-in-part of International Application PCT/US02/020360, filed Jun. 28, 2002, and claims the benefit of U.S. Provisional Application No. 60/301,417, filed Jun. 29, 2001, the disclosures of both of which documents are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to the application of adhesive to a surface. 
   When applying adhesive to a surface, for example for installation of ceramic tile or floor coverings, it is common practice to place a quantity of the adhesive on the surface and to then spread the adhesive with a notched trowel in order to create adhesive beads that are spaced apart. This procedure is time-consuming and inefficient, and requires a substantial amount of clean-up work. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention provides a novel adhesive dispensing cartridge that is disposable or refillable, and an adhesive applicator composed of the cartridge, a cartridge holder having a receptacle for retaining the cartridge and a movable drive element carried by the holder and coupled to the cartridge to force adhesive out of the cartridge. 
   The adhesive dispensing cartridge according to the invention is composed of a housing enclosing a space for containing a quantity of adhesive, the housing having a front end and a rear end, an adhesive delivery element connected at the front end of the housing, the element being composed of a plurality of teeth spaced apart by recesses and being provided with a plurality of adhesive flow passages extending between the space enclosed by the housing and the recesses, and a plate disposed in the space at the rear end of the housing, the plate cooperating with the housing to contain the adhesive and being movable within the housing toward the front end to force adhesive from the space and through the flow passages. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective front view of one embodiment of a cartridge according to the invention. 
       FIG. 2  is view similar to that of  FIG. 1  showing the cartridge of  FIG. 1  provided with a movable protective cap. 
       FIG. 3  is a perspective rear view of the cartridge of  FIG. 1 . 
       FIG. 4  is a detailed view of one end of a component of the cartridge of  FIGS. 1–3 . 
       FIG. 5  is a cross-sectional view taken along line V—V of  FIG. 1 . 
       FIG. 6  is a detailed view of a front portion of an element of the cartridge of  FIGS. 1–5 . 
       FIG. 7  is a bottom plan detail view of the portion shown in  FIG. 6 . 
       FIG. 8  is a perspective view depicting adhesive beads being produced by an applicator according to the invention. 
       FIG. 9  is a simplified side elevational, cross-sectional view of a first embodiment of an applicator equipped with a cartridge according to the present invention. 
       FIG. 10  is a top plan view of the applicator shown in  FIG. 9 . 
       FIG. 11  is a front perspective view of the applicator. 
       FIG. 12  is an elevational view of one component of the applicator. 
       FIG. 13  is a simplified schematic diagram of a circuit for controlling operation of the applicator. 
       FIGS. 14 and 15  are, respectively, a perspective view and a side elevational view of a second embodiment of an applicator equipped with a cartridge according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A preferred embodiment of a cartridge  10  according to the present invention is shown in  FIGS. 1–3 . This cartridge is composed essentially of a housing  12  having the general form of a rectangular prism and composed of a front end  16 , a rear end  18 , and upper side, a lower side, (not visible) and two lateral sides. At least two of the sides are each provided with at least one inwardly projecting land  24  that extends between ends  16  and  18 . 
   Front end  16  is provided, along the lower edge thereof, with an adhesive dispensing element  28  formed to present a series of downwardly projecting teeth  30  spaced from one another by recesses  32 . 
   Housing  12  has a hollow interior that is filled with an adhesive to be dispensed and rear end  18  is constituted by a plate that is movable relative to the remainder of housing  12  toward front end  16  so as to force adhesive out of dispensing element  28 , as will be described in greater detail below. Thus, plate  18  will function as a primary plunger. 
     FIG. 2 , which is a view similar to that of  FIG. 1 , shows element  28 , covered with a protective cap  34  when cartridge  10  is not in use. 
   As can be seen in  FIG. 3 , plate  18  is provided at its edge with grooves that mate with lands  24 . 
     FIG. 4  is a detail view of one end of plate  18 , as viewed from within housing  12 . According to one optional feature of the invention, plate  18  is provided with a flange  36  that extends around the entire periphery of plate  18  and projects into housing  12 . Flange  36  and the grooves that mate with lands  24  cooperate to guide plate  18  so that it remains parallel to font end  16  while being displaced. In addition, flange  36  can be formed to serve as a seal and to prevent plate  18  from backing out of housing  12 . 
     FIG. 5  is a cross-sectional view taken along line V—V of  FIG. 1 .  FIG. 5  shows that housing  12  encloses a space, or chamber,  40  containing adhesive to be dispensed. Element  28  is provided with a plurality of adhesive flow passages  42  each extending between chamber  40  and the base of a respective one of recesses  32 . 
   Further details of dispensing element  28  are shown in  FIGS. 6 and 7 .  FIG. 6 , in particular, shows that, in a preferred embodiment of the invention, each tooth has a flat bottom surface, while each recess  32  has a rounded bottom.  FIG. 7  shows the location of the outlet end of each passage  42  at the base of its respective recess  32 . 
     FIG. 8  depicts adhesive beads  46  produced by an applicator according to the invention. In order to produce these beads, it is only necessary to move cartridge  10  rearwardly, i.e., in the direction from front end  16  to rear end  18 , while simultaneously displacing plate  18  toward front end  16 . As long as the lower surfaces of teeth  30  remain in contact with, or close to, the surface  50  to which the adhesive is to be applied, beads  46  will have cross sections corresponding to those of recesses  32 . 
   Cartridge  10  may be made of any suitable material, such as aluminium, and may be either reusable or disposable. 
     FIG. 9  is a simplified side elevational, cross-sectional view of an applicator equipped with a cartridge  10  according to the present invention. The applicator is a hand-held device having a main housing  60  from which extends a handle  62 . The rear end of main housing  60  is provided with a receptacle for a battery  64 , which is preferably rechargeable. 
   The front end of main housing  60  constitutes a cartridge receptacle  66  in which a cartridge  10  will be held when adhesive is to be dispensed. Cartridge  10  and receptacle  66  are dimensioned so that when cartridge  10  is held in place in receptacle  66 , these lower surfaces of teeth  30  will be substantially flush with the lower surface of receptacle  66 . Cartridge  10  will be held in place in receptacle  66  by a fastening bar  68  that extends across, and is in contact with, front end  16 . 
   Housing  60  contains and electric drive motor  72  having an upward shaft connected to a transmission  74 . Transmission  74  is, in turn, coupled to a bevel gear arrangement that includes an output  76 . Gear  76  is coupled to cogged, or toothed, drive rod  80 . Gear  76  and rod  80  thus form a rack and pinion mechanism. Rod  80  is preferably a solid rod having a square cross section and is guided for longitudinal movement in two guides  86  and  88  that are fixed in housing  60 . 
   The output end of rod  80  carries a secondary plunger  90  that preferably corresponds closely in shape, but is slightly smaller then plate  18 . Rotation of motor  72  thus produces linear movement of rod  80  to advance plunger  90  and plate  18  into cartridge  10 , thus forcing adhesive through passages  42  and into recesses  32 . 
   The operation of motor  72  is controlled by a manually operable variable speed trigger switch  92  and a forward/reverse switch  94  in handle  62 . Trigger switch  92  is coupled to battery  64  and motor  72  in order to cause the speed of motor  72  to vary as a function of the degree of depression of trigger  92 . Circuitry for performing such an operation is already well known in the art. The output shaft of motor  72  may also carry a fan  98  that will produce a flow of air for cooling motor  72 . 
     FIG. 10  is a top plan view of the applicator shown in  FIG. 9  and shows bar  68  pivotally mounted to a hinge  102 . The free end of bar  68  engages a latch  104  that holds bar  68  in a closed position when the applicator is in use. 
     FIG. 11  is a front perspective view of the applicator, with no cartridge being provided in receptacle  66 . Housing  60  is provided with a series of vents  106  that provide ventilating airflow. There may be three such vents along each side of housing  60 . 
     FIG. 12  shows one example of latch  104 , which is composed essentially of a mounting plate  110 , tension spring clips  112  and clip release levers  114 . When levers  112  are in their normal position, as shown in  FIG. 12 , bar  68  is held in a closed condition. In order to release bar  68 , for example in order to replace a cartridge  10 , the user deflects levers  114  toward the rear, thus moving levers  112  away from one another. 
     FIG. 13  is a simplified schematic diagram illustrating the connection of battery  64  to motor  72  via trigger  92 . Trigger  92  is coupled to conventional control circuitry  120  that will vary the power supplied to motor  72  as a function of the degree of depression of trigger  92 . By way of non-limiting example, circuitry  120  could include a simple potentiometer that varies the magnitude of the voltage supplied to battery  72 , or could be a SCR control circuit that varies the rate of application of dry voltage pulses to motor  72 . Circuit  120  could also be constructed according to the teachings of U.S. Pat. No. 4,649,245, Lessig, III et al, the disclosure of which is incorporated herein by reference. Those skilled in the art will be readily aware of other types of control circuits that can be employed. Control circuit  120  can be coupled in a suitable manner to switch  94  to allow for control of the direction of rotation of motor  72 . 
   In order to dispense adhesive with the applicator according to the present invention, it is only necessary for the user to rest the bottoms of teeth  30  on the work surface and place motor  72  into operation while drawing the applicator rearwardly along the surface and controlling the speed of motor  72  in order to coordinate the rate at which adhesive is dispensed with the rate of displacement of the applicator. The application of beads to the work surface may be improved if the applicator is held at a slight angle to the work surface such that the leading edge, i.e., the edge furthest from front end  16 , of the teeth are in contact with the surface and the bottom surfaces of the teeth form an angle of the order 5° with the work surface. 
   When the supply of adhesive in a cartridge has been exhausted, it is only necessary to replace the cartridge in order to continue adhesive application. The empty cartridge may be thrown away, since it is a relatively inexpensive component. 
   If, at the end of an adhesive application task, useable adhesive remains in the cartridge, cap  34  may be placed over element  28  in order to prevent accidental escape of adhesive and maintain the adhesive in a condition for future use. Cap  34  could be configured to additionally engage the rear edge of element  28  in order to completely seal the spaces defined by recesses  32 . 
   A second embodiment of the invention is shown in  FIGS. 14 and 15 . This embodiment has three novel features, any one or more of which could be incorporated into the embodiment of  FIGS. 1–13 . These features are: a curved handle fastened at both ends to the applicator housing; a multi-speed motor control; and a cartridge fastening gate that is connected to the front of the housing by a hinge having a horizontal axis. 
     FIGS. 14 and 15  show a housing  140  with an integrally-formed, curved handle  144  that is fastened at both ends to the upper surface of housing  140 . Handle  144  is shaped to provide a generally D-shaped opening for receiving one hand of the user. 
   This curved handle construction provides two important advantages. Firstly, it helps to rigidify the entire housing. This is an important factor considering the length of the applicator and the inherent weight of a full cartridge, which can be as much as 13.5 lbs. 
   The second advantage is that it allows improved control of the applicator. Given the working weight of a loaded applicator, two-handed control is a necessity. The D-handle construction facilitates this efficiently by the provision a handgrip  148  at the front of the handle, and thus at the front of the applicator, for the other hand of the user. Preferably, handgrip  148  is placed as far forward and as low to the housing body as practically possible. The resulting forward hand position affords the user maximum control when using the applicator for either a vertical wall or horizontal floor application. Also preferably, the handle is positioned and dimensioned so that the center of gravity of the applicator, when loaded, is between the fore and aft grips. 
   The multi-speed motor control, as opposed to the continuously variable speed control of the first embodiment, provides a major advantage in that it allows the user to rely on any one of several recommended pre-set plunger speeds to govern the flow of adhesive from the cartridge. These speeds correlate directly with different cartridges filled adhesives having different flow characteristics applicable to the adhesion of specific materials. For example, adhesives for ceramic tile, vinyl and linoleum flooring, and laminate wood flooring may have different consistencies such that a different plunger speed is optimum for each adhesive. This feature is beneficial because and applicator according to the invention is intended to accept cartridges pre-filled with adhesives of different consistencies and having different sized application holes and teeth. The ability to select a plunger speed that is preset for a given type of adhesive considerably cuts down on the immediate skill, or learning curve, required when using this applicator. 
   In this embodiment, speed control  120  could be constructed in the manner described in U.S. Pat. No. 5,802,248, Miller et al, the disclosure of which is incorporated herein by reference. 
   The multi-speed motor control employs a speed setting switch  152  and an operating trigger  156 , which may both be installed in handle  144 , although they could be placed elsewhere on housing  140 . Switch  152  may have two or more preset speed settings and, if desired, a variable speed setting allowing the plunger speed to be varied as a function of the amount of trigger depression, as in the first-described embodiment, 
   The cartridge fastening gate of the second embodiment, shown at  168  in  FIGS. 14 and 15 , is mounted to housing  140  by a hinge  170  and is held in a closed position by pressure release latches  174  (one of which is not visible) at opposed ends of gate  168 . Fastening gate  168  may have a generally rectangular form, with a long dimension and a short dimension, and is connected to housing  140  to pivot about an axis parallel to the long dimension, or about an axis that is horizontal when the applicator is in a position to apply adhesive to a floor surface. Pressure release latches  174  are disposed at the short sides of gate  168 . 
   Fastening gate  168  provides important advantages. One of these is that it provides a complete and solid surface for the front of the cartridge to push against when the cartridge is under pressure during adhesive application. Upon release, the gate flips up and out of the way, staying close to the applicator, as opposed to the bar design of  FIGS. 9–12  hinged on one side, which renders the hinge vulnerable to breakage at the hinge point when in the open position. 
   Latches  174  can be devices that are widely used, such conventional portable power applicator battery pack releases. 
   The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without undue experimentation and without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. The means, materials, and steps for carrying out various disclosed functions may take a variety of alternative forms without departing from the invention. 
   Thus the expressions “means to . . . ” and “means for . . . ”, or any method step language, as may be found in the specification above and/or in the claims below, followed by a functional statement, are intended to define and cover whatever structural, physical, chemical or electrical element or structure, or whatever method step, which may now or in the future exist which carries out the recited function, whether or not precisely equivalent to the embodiment or embodiments disclosed in the specification above, i.e., other means or steps for carrying out the same functions can be used; and it is intended that such expressions be given their broadest interpretation.

Technology Classification (CPC): 1