Module for dispensing adhesive and adhesive applicator incorporating the module

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.

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.

DETAILED DESCRIPTION OF THE INVENTION

A preferred embodiment of a cartridge10according to the present invention is shown inFIGS. 1–3. This cartridge is composed essentially of a housing12having the general form of a rectangular prism and composed of a front end16, a rear end18, 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 land24that extends between ends16and18.

Front end16is provided, along the lower edge thereof, with an adhesive dispensing element28formed to present a series of downwardly projecting teeth30spaced from one another by recesses32.

Housing12has a hollow interior that is filled with an adhesive to be dispensed and rear end18is constituted by a plate that is movable relative to the remainder of housing12toward front end16so as to force adhesive out of dispensing element28, as will be described in greater detail below. Thus, plate18will function as a primary plunger.

FIG. 2, which is a view similar to that ofFIG. 1, shows element28, covered with a protective cap34when cartridge10is not in use.

As can be seen inFIG. 3, plate18is provided at its edge with grooves that mate with lands24.

FIG. 4is a detail view of one end of plate18, as viewed from within housing12. According to one optional feature of the invention, plate18is provided with a flange36that extends around the entire periphery of plate18and projects into housing12. Flange36and the grooves that mate with lands24cooperate to guide plate18so that it remains parallel to font end16while being displaced. In addition, flange36can be formed to serve as a seal and to prevent plate18from backing out of housing12.

FIG. 5is a cross-sectional view taken along line V—V ofFIG. 1.FIG. 5shows that housing12encloses a space, or chamber,40containing adhesive to be dispensed. Element28is provided with a plurality of adhesive flow passages42each extending between chamber40and the base of a respective one of recesses32.

Further details of dispensing element28are shown inFIGS. 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 recess32has a rounded bottom.FIG. 7shows the location of the outlet end of each passage42at the base of its respective recess32.

FIG. 8depicts adhesive beads46produced by an applicator according to the invention. In order to produce these beads, it is only necessary to move cartridge10rearwardly, i.e., in the direction from front end16to rear end18, while simultaneously displacing plate18toward front end16. As long as the lower surfaces of teeth30remain in contact with, or close to, the surface50to which the adhesive is to be applied, beads46will have cross sections corresponding to those of recesses32.

Cartridge10may be made of any suitable material, such as aluminium, and may be either reusable or disposable.

FIG. 9is a simplified side elevational, cross-sectional view of an applicator equipped with a cartridge10according to the present invention. The applicator is a hand-held device having a main housing60from which extends a handle62. The rear end of main housing60is provided with a receptacle for a battery64, which is preferably rechargeable.

The front end of main housing60constitutes a cartridge receptacle66in which a cartridge10will be held when adhesive is to be dispensed. Cartridge10and receptacle66are dimensioned so that when cartridge10is held in place in receptacle66, these lower surfaces of teeth30will be substantially flush with the lower surface of receptacle66. Cartridge10will be held in place in receptacle66by a fastening bar68that extends across, and is in contact with, front end16.

Housing60contains and electric drive motor72having an upward shaft connected to a transmission74. Transmission74is, in turn, coupled to a bevel gear arrangement that includes an output76. Gear76is coupled to cogged, or toothed, drive rod80. Gear76and rod80thus form a rack and pinion mechanism. Rod80is preferably a solid rod having a square cross section and is guided for longitudinal movement in two guides86and88that are fixed in housing60.

The output end of rod80carries a secondary plunger90that preferably corresponds closely in shape, but is slightly smaller then plate18. Rotation of motor72thus produces linear movement of rod80to advance plunger90and plate18into cartridge10, thus forcing adhesive through passages42and into recesses32.

The operation of motor72is controlled by a manually operable variable speed trigger switch92and a forward/reverse switch94in handle62. Trigger switch92is coupled to battery64and motor72in order to cause the speed of motor72to vary as a function of the degree of depression of trigger92. Circuitry for performing such an operation is already well known in the art. The output shaft of motor72may also carry a fan98that will produce a flow of air for cooling motor72.

FIG. 10is a top plan view of the applicator shown inFIG. 9and shows bar68pivotally mounted to a hinge102. The free end of bar68engages a latch104that holds bar68in a closed position when the applicator is in use.

FIG. 11is a front perspective view of the applicator, with no cartridge being provided in receptacle66. Housing60is provided with a series of vents106that provide ventilating airflow. There may be three such vents along each side of housing60.

FIG. 12shows one example of latch104, which is composed essentially of a mounting plate110, tension spring clips112and clip release levers114. When levers112are in their normal position, as shown inFIG. 12, bar68is held in a closed condition. In order to release bar68, for example in order to replace a cartridge10, the user deflects levers114toward the rear, thus moving levers112away from one another.

FIG. 13is a simplified schematic diagram illustrating the connection of battery64to motor72via trigger92. Trigger92is coupled to conventional control circuitry120that will vary the power supplied to motor72as a function of the degree of depression of trigger92. By way of non-limiting example, circuitry120could include a simple potentiometer that varies the magnitude of the voltage supplied to battery72, or could be a SCR control circuit that varies the rate of application of dry voltage pulses to motor72. Circuit120could 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 circuit120can be coupled in a suitable manner to switch94to allow for control of the direction of rotation of motor72.

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 teeth30on the work surface and place motor72into operation while drawing the applicator rearwardly along the surface and controlling the speed of motor72in 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 end16, 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, cap34may be placed over element28in order to prevent accidental escape of adhesive and maintain the adhesive in a condition for future use. Cap34could be configured to additionally engage the rear edge of element28in order to completely seal the spaces defined by recesses32.

A second embodiment of the invention is shown inFIGS. 14 and 15. This embodiment has three novel features, any one or more of which could be incorporated into the embodiment ofFIGS. 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 15show a housing140with an integrally-formed, curved handle144that is fastened at both ends to the upper surface of housing140. Handle144is 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 handgrip148at the front of the handle, and thus at the front of the applicator, for the other hand of the user. Preferably, handgrip148is 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 control120could 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 switch152and an operating trigger156, which may both be installed in handle144, although they could be placed elsewhere on housing140. Switch152may 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 at168inFIGS. 14 and 15, is mounted to housing140by a hinge170and is held in a closed position by pressure release latches174(one of which is not visible) at opposed ends of gate168. Fastening gate168may have a generally rectangular form, with a long dimension and a short dimension, and is connected to housing140to 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 latches174are disposed at the short sides of gate168.

Fastening gate168provides 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 ofFIGS. 9–12hinged on one side, which renders the hinge vulnerable to breakage at the hinge point when in the open position.

Latches174can be devices that are widely used, such conventional portable power applicator battery pack releases.

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.