Abstract:
An elongated liquid polish dispenser which can be longitudinally attached to a hand-held rotary buffer such that a thumb switch to operate the dispenser is placed opposite a trigger on the buffer&#39;s handle is described. The dispenser can be firmly attached by a built-in strap to several popular models of professional heavy duty polishers without obscuring vent holes of those models. The thumb switch activates an electric pump which pumps liquid polish through a nozzle and onto a work surface.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 61/003,145 filed Nov. 14, 2007, hereby incorporated by reference in its entirety for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to devices that attach to power tools and dispense fluid on a work surface, and more particularly to thumb-operated devices that attach to hand-held polishers wherein a work facilitating or enhancing liquid is dispensed from the devices onto surfaces to be polished or buffed. 
     Hand-held surface finishing power tools, such as hand-held rotary polisher  102  in  FIG. 1 , are well-known in the art. Rotary polishers are often used by original equipment manufacturers, auto body shops, and professional detailers to sand, polish, or otherwise finish surfaces on vehicles such as automobiles, recreational vehicles, boats, aircraft, and other vehicles. Rotary polishers can be used for polishing other surfaces as well, such as those on buildings, bridges, and other structures. Rotary polishers are sometimes called rotary buffers, variable speed buffers, buffing or polishing machines, circular polishers, or orbital polishers. Some exemplary rotary polishers include the DeWalt DW849 7″/9″ Electronic Variable Speed Polisher, Milwaukee 5460 7/9 in. Dial Speed Control Polisher, Makita 9227C 7″ Electronic Sander-Polisher, and Porter Cable 7424 6″ Variable-Speed Random-Orbit Polisher. 
     Rotary polisher  102  includes rotatably attached finishing disk  104  comprising disk-like backing pad  112  upon which a buffing pad  106  can be placed. While a user holds the polisher against a work surface, the polisher rotates the buffing pad against the work surface at a range of angular velocities depending upon the model, e.g., 600, 1000, 1800, 3000, or 3600 revolutions per minute (RPM). Some models of buffing machines have variable speeds which allow a user to control the angular velocity or rotation speed of the tool. Some models have an adjustable governor setting which limits rotation speed, which can be used for more sensitive operations where too much speed could cause damage to the work surface. Non-rotary surface finishing power tools are also available, such as those that vibrate a pad or employ a belt. 
     On many hand-held polishers, the speed of the device is controlled by a trigger switch on a handle, such as speed control trigger  108  on handle  110  of polisher  102 . The placement of speed control trigger  108  allows a user to grip handle  110  with one hand and comfortably depress speed control trigger  108  with the same hand&#39;s index finger, thereby allowing an uninterrupted grip of handle  110 . The user&#39;s other hand can hold a handle (not shown) on the distal end of the polisher to direct and stabilize finishing disk  104  on a work surface. 
     A wide variety of attachments can serve as finishing disk  104  on rotary polisher  102 . Finishing disks can include sisal wheels, spiral sewn cotton wheels, loose cotton wheels, canton flannel wheels, acrylic buffing wheels, treated spiral sewn wheels, scrubber wheels, cushion buffs, denim buffing wheels, domet flannel wheels, expanding sander wheels, facer buffs, finger buffs, flap wheels, mushroom buffs, sanding drums, razor buffs, scrubbing mushroom buffs, string buffs, vented buffs, treated vented buffs, and other finishing attachments. Circular buffing pad  106  wraps around rigid or semi-rigid backing pad  112 , which can be made of rubber, phenolic resin, metal, or other types of suitable material. A backing pad is sometimes called a back-up plate. Because of the way buffing pad  106  wraps around backing pad  112 , buffing pad is sometimes called a polishing bonnet. Other styles of buffing pads include those that attach to the backing pad by hook-and-loop fasteners (e.g., VELCRO®). Buffing pad  106  can be made of soft fabric, such as cotton, wool, nylon, or foam and are often between ⅞ and 1¼ inches thick. 
     Power polishers and sanders are somewhat interchangeable, depending on the job. By attaching a fine sanding disk to rotary polisher  102 , the polisher can sand a surface. 
     The finishing pad employed often depends upon the material of the surface to be finished (e.g., aluminum, fiberglass, clear-coat), the stage of surface finishing, the ending smoothness required, the speed at which a customer requires work to be completed, the liquid polish used, cost, and other like factors. The same factors dictate the size of the pads employed. Pads come in various sizes, for example in 4, 5, 5¼, 6, 7, and 12-inch diameters. 
     During polishing, it is often desirable to apply a polishing compound to a surface to aide in polishing. The compound is often in liquid form, but can also be a general fluid form. In practice, liquid polish is often squirted from a bottle onto the work surface. Squirting the polishing liquid from a bottle usually involves a user stopping and setting down the buffing machine, picking up the bottle, squirting liquid polish onto the surface from the bottle, then picking up the buffing machine and restarting it. Such a process tends to be tedious and time consuming. 
     During sanding, water or oil can be applied to a work surface to reduce dust and lubricate and cool the tool and surface. Other fluids, such as air or inert gases can be dispensed (i.e., blown) on the surface for cooling as well. 
     Attempts have been made in the prior art to incorporate a liquid polish dispensing mechanism into a rotary polisher. However, such designs typically involve a redesign of the polisher so that components such as reservoirs, tubing, pumps, and nozzles can be plumbed inside the polisher. Also, integrated dispensers are not normally easily removed for cleaning. Some prior art designs dispense polish underneath the center of the buffing pad. However, with such designs it is difficult for an operator to see exactly when and how much product is dispensed when the finishing disk is held against the work surface and/or is spinning. 
     There exists a need for an improved liquid polish dispenser. 
     BRIEF SUMMARY OF THE INVENTION 
     Embodiments in accordance with the present disclosure relate to liquid polish dispensers for use with rotary polishers or other hand-held surface finishing tools. For example, certain embodiments relate to a liquid polish dispenser which can be longitudinally attached to a hand-held rotary polisher or other hand-operable surface finishing power tools such that a thumb-switch to operate the dispenser is conveniently placed proximal to and optionally opposite a trigger on the tool&#39;s handle. The dispenser can be firmly attached to rotary polishers by a strap strategically placed to avoid vent holes on the polishers. The thumb-switch activates an electric pump which pumps liquid polish through a nozzle and onto a work surface so that the user can easily determine how much and control the amount of liquid polish product that is dispensed. 
     One embodiment relates to a detachable fluid dispenser for a hand-operable surface finishing power tool. The dispenser typically includes an elongated casing adapted to attach longitudinally to a hand-operable surface finishing power tool, an attachment mechanism adapted to detachably secure the dispenser to the tool, and a container attachment mechanism adapted to removably hold a fluid container. The dispenser also typically includes a product delivery tube routed from the casing over the exterior of the tool connecting to a nozzle, and an electric pump coupled to the delivery tube. The pump is typically adapted to receive fluid from an attached fluid container and pump the fluid through the tube and nozzle. 
     Another embodiment relates to a detachable fluid dispenser for a hand-operable surface finishing power tool. The dispense typically includes an elongated casing adapted to attach longitudinally to a hand-operable surface finishing power tool, means for detachably securing the dispenser to the tool, and means for attachment of a fluid container to the casing. The dispenser also typically includes a product delivery tube routed from the casing over the exterior of the tool connecting to a nozzle and an electric pump coupled to the delivery tube. The pump is typically adapted to receive fluid from an attached container and pump the fluid through the tube and nozzle. 
     Yet another embodiment relates to a detachable, liquid polish dispenser for a hand-held rotary polisher. The dispenser typically includes an elongated casing adapted to attach longitudinally to a hand-held rotary polisher, a strap adapted to secure the dispenser to the polisher, means for rigid attachment of a liquid container to the casing, and an electric pump adapted to receive liquid from the container. The dispenser also typically includes a feed line routed from the casing along an exterior of the polisher to a distal end of the polisher and a nozzle extending over the polisher. The nozzle is typically connected to the feed line and directed to dispense liquid directly onto a surface to be polished. 
     A further understanding of the nature and the advantages of the embodiments disclosed and suggested herein may be realized by reference to the remaining portions of the specification and the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a prior art illustration of a popular hand-held rotary polisher. 
         FIG. 2  is an illustration of a detachable fluid dispenser in accordance with an embodiment. 
         FIG. 3  is an illustration of the dispenser of  FIG. 2  attached to the rotary polisher of  FIG. 1 . 
         FIG. 4A  is a perspective view of the outside of the right hand casing of the dispenser of  FIG. 2 . 
         FIG. 4B  is a perspective view of the inside of the right hand casing of the dispenser of  FIG. 2 . 
         FIG. 5A  is a perspective view of the outside of the left hand casing of the dispenser of  FIG. 2 . 
         FIG. 5B  is a perspective view of the inside of the left hand casing of the dispenser of  FIG. 2 . 
         FIG. 6  is a perspective view of internal components of the dispenser in  FIG. 2 . 
         FIG. 7  is a perspective view of internal and external components of the dispenser in  FIG. 2 . 
         FIG. 8  is a vertical cross section of the dispenser of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 2  is an illustration of detachable fluid dispenser in accordance with an embodiment. With respect to  FIG. 2 , detachable fluid dispenser  220  includes elongated casing  222 , strap  224 , container attachment mechanism  226 , product delivery tube  228 , and nozzle  230 . Dispenser  220  may be adapted to attach to any rotary polisher or other hand-held too. For example, in certain aspects, dispenser  220  is adapted to attach to several popular models of rotary polishers, and includes indentation  238  in order to rest on a popular polisher&#39;s dorsal resting block. A standard, over-the-counter, twelve-ounce spray bottle container  234  can be screwed snugly into threads (not shown) inside container attachment mechanism  226 . It should be appreciated that other non-standard containers may be coupled with an appropriate attachment mechanism (e.g. threads). 
       FIG. 3  shows the dispenser of  FIG. 2  attached to the rotary polisher of  FIG. 1 . Elongated casing  222  is shown adapted to attach longitudinally using strap  224  to the polisher. Strap  224  can be made of a resilient material and can be secured over itself with hook-and-loop fasteners (e.g., VELCRO®), snaps, buckles, zippers, hook-and-eye closures, and other fasteners as would be apparent to one skilled in the art. A single 2½″-wide nylon strap, similar to a backpack strap, and clipped together with a male/female clip has been found to be effective. Strap  224  can also be made of a non-resilient material, such as metal, thermoplastic, or leather. Although non-resilient straps may not immediately conform to varied diameters of power finishing tools, non-resilient straps offer the opportunity to minimize inertial resonance of the tool and dispenser combination by more rigidly securing the dispenser to the tool. 
     In certain aspects, elongated casing  222  and strap  224  are adapted such that when the dispenser is attached, vent holes on various models of rotary polishers, such as the exemplary models discussed above, are unimpeded. Slight indentation  238  allows dispenser  220  to rest against one popular tool&#39;s dorsal resting block as shown in the figure. 
     Other removable attachment mechanisms besides a strap can be used, such as hooks, threaded studs with butterfly or knurled nuts, screws, clips, suction cups, hook-and-loop fasteners, and other releasable attachment mechanisms known in the art. 
     Longitudinally attaching the casing of the elongated dispenser to the power finishing tool advantageously shortens the distance between the centers of mass of the dispenser and tool and allows a greater contact region between the dispenser and tool for various attachment mechanisms. By reducing the distance between the centers of mass, the combined tool/dispenser is more akin to a single rigid body, rather than two coupled rigid bodies. Thus, the inertias of the dispenser and tool are more tightly phased and thus less likely to ‘knock’ against each other when the tool is vibrating. The greater contact region between the dispenser and tool allows a greater variety of attachment mechanisms and/or wider, broader, or more ergonomic attachment mechanisms to be used. In U.S. Pat. No. 3,104,783 to Hall and U.S. Pat. No. 5,649,508 to Rost et al., the disclosed dispensers are of cantilevered designs which generally increase the displacements caused by vibrations, especially near the distal ends of the dispensers, and require smaller attachment mechanisms. 
     A longitudinal attachment also advantageously helps minimize protrusions which can occlude an operator&#39;s view of the work surface or inadvertently bump into vehicle accessories (e.g., antennas, fog lights, side mirrors), inside edges, and other features on a vehicle being polished. 
     Running the elongated dispenser down the length of a polisher, such as one of the exemplary models described above, allows a thumb switch to be conveniently located near the handle of the polisher without separating the thumb switch from the main shell of the dispenser. As shown in  FIG. 3 , thumb switch  236  is oriented such that thumb switch  236  is operable by a thumb on a hand that grips handle  110  and squeezes trigger  108  with an index finger. Thus, thumb switch  236  can be operated without interrupting one&#39;s grip on handle  110 . 
     In certain aspects, as shown, product delivery tube  228  is routed from casing  222  over the exterior of hand-operable surface finishing power tool  102  and connects to nozzle  230 . A product delivery tube is sometimes called a feed line. Routing the tube outside the tool helps allow dispenser  220  to be more easily detached from tool  102 , and also, if the tube is clear or translucent, gives an operator a clearer view of product as it moves through the tube. The operator may also be able to see obstructions, such as those caused by dried polish or contaminants, in the tube. 
     In certain aspects, container attachment mechanism  226  is positioned so that the opening (not shown) of container  234  is oriented downward during normal operation, e.g., fluid inside container  234  drains downward when connected to dispenser  220  and the tool is horizontal and finishing disk  104  is directed downward, substantially as shown. Thus, gravity assists in draining liquid polish from the bottle so that there is effectively more usable volume in the container than with a conventional siphon straw system, and less product is wasted. This can save on product costs, as well as reduce waste. Also, the pump being at the bottom is subjected to a higher head pressure from the liquid so that the pump operates more efficiently. 
     In certain aspects, a clear or translucent bottle serving as container  234  can be used to allow a user to see the amount of liquid left and rate at which it is consumed. Container attachment mechanism  226  positions container  234  out in front of a user so the user can more easily see the contents of the bottle. In certain aspects, a slight forward tilt of container  234  is provided as shown to help a user better view the product inside. 
     In one aspect, container attachment mechanism  226  includes sleeve  240  that surrounds the perimeter or circumference of container  234 . If a seal between container  234  and container attachment mechanism  226  leaks, then such leakages are contained within sleeve  240 , preventing a mess. Also, if extra liquid polish is left in container  234  when container  234  is unscrewed, the spillage will drain into cup-like sleeve  240 . 
       FIGS. 4A-4B  and  5 A- 5 B illustrate different views of an exemplary dispenser casing. As shown, elongated casing  222  (see  FIG. 2 ) can be comprised of right hand casing  442  and left hand casing  544 . The two longitudinal halves can be assembled by screws, rivets, or other fasteners. Power receptacle  550  is usable for charging internal batteries. The assembly of left and right casings  442  and  544  can be sealed with a gasket or other adhesive in order to prevent outside contaminants or stray liquid polish from entering the casing. Thumb switch  236  (see  FIG. 3 ) can include thumb pad  546  (see  FIG. 5B ), which can be sealed. Strap  224  can be comprised of right hand strap  446  and left hand strap  548 , with hook-and-loop strips to releasably attach the right and left hand straps  446  and  548  to each other to form a solid strap. 
       FIG. 6  illustrates various internal components of a dispenser according to one embodiment. As shown, thumb switch  236  (see  FIG. 3 ) can comprise switch  648 . Switch  648  controls the flow of electricity from battery  650 . A set of lithium ion dry cells connected in series to create a 7.2-volt battery has been observed to provide enough power for a small fluid pump and last long enough for a complete polishing job. Battery  650  is recharged through receptacle  550 . 
       FIG. 7  illustrates components of the dispenser of  FIG. 2 . As shown, electric pump  752  is coupled to product delivery tube  228  and is adapted to receive fluid from container  234  (see  FIG. 2 ) and pump the fluid through tube  228  and nozzle  230 . 
       FIG. 8  is a vertical cross section of the dispenser of  FIG. 2 . Thumb switch  236  including thumb pad  546  and switch  648 , receptacle  550 , battery  650 , electric pump  752 , and a portion of product delivery tube  228  can be packaged inside elongated casing  222  as shown. Product delivery tube  228  is routed outside casing  222 , over the exterior of the tool to nozzle  230 . Container attachment mechanism  226 , which can be integral to casing  222 , can also be integral to sleeve  240 . 
     If tool  102  has a suitable power receptacle, a power plug from dispenser  220  can be adapted to plug into the receptacle, thereby powering the dispenser. This can allow more power to be supplied to the pump than would otherwise be supplied by dry cell batteries and/or allow battery  650  to be constantly recharged. The use of a plug into a local power socket on the tool obviates any need for a separate power cord extending to a wall outlet if batteries are not used. 
     In certain aspects, nozzle  230  is covered by tube cap  754  (see  FIG. 7 ) in order to prevent liquid polish from drying in the nozzle and to prevent spillage out nozzle  230 . 
     To clean the internal wetted regions of dispenser  220 , container  234  may be filled with water or another cleaning agent and the pump activated to flow water through pump  752 , product delivery tube  228 , and nozzle  230 . 
     In certain aspects, pump  752  can also be operated in reverse by switching the polarity of the power by a double-pole double-throw (DPDT) toggle switch. This switch can be the same as thumb switch  236  or a separate switch. In reverse, pump  752  can sip water from a bucket in which nozzle  230  rests back through tube  228  and into container  234 . This reverse pumping can be used for convenient cleaning. For example, at the end of a job and after the last of the usable liquid polish in container  234  is drained, the nozzle can be set in water and the pump reversed without unscrewing the container. This will not only flush the dispenser nozzle, tubes, and pump, but also wash container  234  with cleaning water. After container  234  is filled, pump  752  can then be reversed again (to forward operation) to pump out the dirty cleaning water from container  234 . A few iterations of this method can clean the apparatus without the need to remove and replace container  234 . 
     In some embodiments, the reverse pumping process can be used to fill container  234  with liquid polish by inserting the nozzle in a bottle of new polish. For example, at the beginning of a job the nozzle can be set in a new bottle of liquid polish, and the polish will be sucked into container  234 . Container  234  is thus filled without removing it from dispenser  220 . 
     Besides using the reverse pumping process for cleaning, reverse pumping can be used to dilute liquid polish in container  234  without the need to remove container  234  from the dispenser. For example, if liquid polish from the dispenser appears a bit too thick, an operator can submerge nozzle  230  in a pail of water and trigger the reverse pump. Water will be pumped backwards into container  234  and mix with the thick polish, thereby thinning or diluting the polish. The operator can then set the pump to forward flow and dispense a bit of liquid polish to test its consistency. The operator can repeat this process in small increments until the polish in container  234  is of the appropriate consistency. 
     Nozzle  230  and/or product delivery tube  228  can be made of resilient material, such as rubber or polyethylene. A soft, resilient nozzle helps prevent scratches and other damage to vehicles if the nozzle is caught on an edge or inadvertently jammed against a surface. A resilient nozzle also lessens the possibility of the nozzle breaking in such situations. 
     Nozzle  230  and/or product delivery tube  228  can also be curvilinear, helical, S-shaped, or otherwise serpentine such that the nozzle or tube is more resilient than it otherwise would be, given the same cross section and material of the tube and nozzle. Curves in a serpentine delivery tube can be sized such that the natural frequency of the tube is lower than or above that the normal operating frequency (RPM) of a rotary polisher. 
     In certain aspects, nozzle  230  is removable. A removable nozzle allows easier cleaning of the nozzle and distal end of product delivery tube  228  as well as the option of using different nozzles for different patterns (e.g., stream, heavy spray, fine spray patterns). 
     Referring back to  FIG. 3 , in certain aspects product delivery tube  228  and nozzle  230  extend no farther than the planform of the tool. The planform is the vertical boundary of a plan view of the tool. It has been found that containing the tube and nozzle within the planform boundary helps keep vibrations of the tool from unduly swinging the nozzle tip. Large swings in the nozzle while dispensing can result in product being slung unpredictably, such as toward the operator. 
     Referring again to  FIG. 8 , in one embodiment, a viscosity compensation mechanism  856  is integrated with pump  752  such that pump  752  pumps fluids with varying viscosities at substantially similar flow rates. Substantially similar flow rates include flow rates within ±10%, ±25%, or other similar rates to each other. Viscosity compensation mechanism  856  can include a sensor that senses fluid flow with feedback to a controller which controls pump speed, and can also include a governor such that pump  752  pumps at a constant speed for various fluid consistencies. 
     In certain aspects, dispenser  220  includes an indicator to indicate if attached container  234  has run dry. Such an indicator can include an audible alarm, an indicator light, a vibration change, a brief interruption in the pump motor windup, and other indicators. Also, indication may be provided to a user by the pump sounding different or by a deactivation of thumb switch  236 . 
     In the foregoing specification, the invention is described with reference to specific embodiments thereof, but those skilled in the art will recognize that the invention is not limited thereto. Various features and aspects of the above-described invention may be used individually or jointly. Further, the invention can be utilized in any number of environments and applications beyond those described herein without departing from the broader spirit and scope of the specification. The specification and drawings are, accordingly, to be regarded as illustrative rather than restrictive.