Patent Publication Number: US-6698670-B1

Title: Friction fit paint cup connection

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to the connection between a fluid supply cup and an adapter for a fluid applicator, more particularly to the connection between a paint cup and an adapter for a paint sprayer. 
     2. Description of the Related Art 
     Typically, the connection between a fluid supply and a fluid applicator, such as a paint sprayer for automobile painting and repainting in body shops, is via an adapter between the fluid supply and the sprayer, such as with a threaded connection between a supply cup and the adapter. However, it is difficult to prevent leaking from threading connections without precision machining of the threads or the use of seals, particularly for threaded connections that have short lengths. Also, it is difficult to quickly engage and disengage a threaded supply cup and an adapter. 
     Attempts have been made to create a connection between a supply cup and an adapter that can be engaged and disengaged quickly and easily. U.S. Published Applications US 2003/0006311 and US 2002/0134861 disclose a connection between the paint cup and the adapter with several parts, including a bayonet type connection. However, the connections in these applications are unnecessarily complex and do not solve the problem of sealing between the supply cup and the adapter. 
     What is needed is a connection between a fluid supply cup and an adapter that can be engaged and disengaged quickly and easily, and that provides a strong, tight seal around the connection. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with the present invention, a cover-connector is provided for covering a fluid supply container and connecting the container to a conduit, wherein one of the container and the conduit has a male frustoconical connecting surface and the other one of the container and the conduit has a threaded connecting surface. The novel cover-connector comprises a conduit side with a conduit connecting region, a container side with a container connecting region, and a passageway between the connecting regions, wherein one of the connecting regions has a female frustoconical surface having an acute frustoconical angle complementary to the male frustoconical connecting surface for frictional connection therebetween, and wherein the other one of the connecting regions has a threaded portion complementary to the threaded connecting surface for threaded connecting therebetween. 
     In one embodiment, a novel cover-connector for covering and connecting a paint container to a male tapered hollow bore adapter for use with a paint sprayer includes a generally frustoconical cover having an axis and extending from a vertex region to an edge at an obtuse frustoconical angle facing toward the paint container when covering the paint container, a container connecting region with threads adjoining the cover edge and extending toward the paint container when covering the paint container, the threads being normal to the axis, a generally frustoconical female fitting integrally connected to the cover at the vertex region, the fitting extending from the cover generally axially opposite from the container connecting region for receiving the male tapered hollow bore adapter, the fitting being angled to open axially and radially outwardly at an acute angle from the axis to a distal fitting end generally defining a plane normal to the axis, the fitting being complementary to the adapter while providing for frictional engagement therebetween, a passageway between the container connecting region and the fitting, and a generally cylindrical support wall extending axially from the cover edge to a distal wall end in the plane, whereupon engagement of the threads with the paint container and the fitting with the adapter provides fluid communication between the paint container and the adapter. 
     Also in accordance with the present invention, a fluid supply assembly for use with a fluid applicator comprises a fluid container and a conduit, wherein one of the container and the conduit has a male frustoconical connecting surface and the other one of the cover and the conduit has a threaded connecting surface, and a cover-connector for covering the container and connecting the container to the conduit, the cover-connector including a conduit side with a conduit connecting region, a container side with a container connecting region, and a passageway between the connecting regions, wherein one of the connecting regions has a female frustoconical surface having an acute frustoconical angle complementary to the male frustoconical connecting surface for frictional connection therebetween and wherein the other one of the connecting regions has a threaded portion complementary to the threaded connecting surface for threaded connection therebetween. 
     Also in accordance with the present invention, a novel method of connecting a fluid container to a fluid applicator comprises the steps of providing a conduit in fluid communication with the fluid applicator, providing the container, wherein one of the container and the conduit has a male frustoconical connecting surface and the other one of the container and the conduit has a threaded connecting surface, providing a cover-connector having a conduit side with a conduit connecting region, a container side with a container connecting region, and a passageway between the connecting regions, wherein one of the connecting regions has a female frustoconical surface having an acute frustoconical angle complementary to the male frustoconical connecting surface, and wherein the other of the connecting regions has a threaded portion complementary to the threaded connecting surface, threadingly connecting the threaded portion and the threaded connecting surface, and engaging the male frustoconical connecting surface with the female frustoconical surface and rotating the male frustoconical connecting surface and the female frustoconical surface with respect to one another, for frictional connection therebetween. 
    
    
     These and other objects, features and advantages are evident from the following description of the present invention, with reference to the accompanying drawings. 
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a side elevation view of gravity-feed paint sprayer with a novel fluid supply assembly according to the present invention having friction fit tapered surfaces. 
     FIG. 2 is an exploded side sectional view of the fluid supply assembly of the present invention. 
     FIG. 3 is an assembled side sectional view of the fluid supply assembly of the present invention. 
     FIG. 4 is a side elevation view of an adapter of the fluid supply assembly of the present invention. 
     FIG. 5 is a perspective partial sectional view of the fluid supply assembly of the present invention. 
     FIG. 6 is an exploded side sectional view of a second embodiment of a fluid supply assembly according to the present invention. 
     FIG. 7 is an assembled side sectional view of the second embodiment of the fluid supply assembly of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referrng to FIGS. 1,  2  and  5 , a friction fit fluid supply assembly  10 ,  10   b  for a fluid applicator  2 , is shown. The friction fit supply assembly  10 ,  10   b  includes a cover-connector  14 ,  14   b  for covering and connecting a fluid container  12 ,  12   b  to a conduit, such as adapter  16  or a hollow bore channel  13  in fluid applicator  2 . One of the container  12 ,  12   b  and the conduit has a male frustoconical connecting surface  62 ,  44   b , and the other has a threaded connecting surface, such as threads  28  on container  12  or threads  60  at channel  13 . The novel cover-connector  14 ,  14   b  includes a conduit side  17 ,  17   b  with a conduit connecting region  20 ,  86 , a container side  15 ,  15   b  with a container connecting region  80 ,  80   b , and a passageway between the conduit connecting region and the container connecting region, such as bore  24   b , wherein one of the connecting regions has a female frustoconical surface  44 ,  62   b  having an acute frustoconical angle complementary to the male fiustoconical connecting surface  62 ,  44   b  for frictional connection therebetween, and wherein the other of the connecting regions has a threaded portion  30 ,  58   b  complementary to the threaded connecting surface  28 ,  60  for threaded connecting therebetween, whereupon frictional connection between the female frustoconical surface  44 ,  62   b  and the male frustoconical surface  62 ,  44   b  and threaded connection between the threaded portion and the threaded connecting surface provides for fluid communication between the container and the conduit. 
     The friction fit and engagement between cover-connector  14  and either container  12   b  or the conduit, such as adapter  16 , provides a strong seal preventing fluid from leaking, and is easy to engage and disengage allowing for easy assembly of fluid supply assembly  10 ,  10   b.    
     In a preferred embodiment, fluid supply assembly  10 ,  10   b  is for feeding liquid, such as paint, to a liquid applicator, such as a paint sprayer  2 ; therefore the present invention will be described for a paint sprayer, such as a gravity feed paint sprayer for use in applying paint  1  to coat substrate surfaces. In one embodiment, paint sprayer  2  is used in the automotive refinishing market, such as automobile body shops, for repainting automobiles. 
     Although fluid supply assembly  10  is described herein for a paint sprayer, it alternatively can be used for supplying other flowable fluids, such as beverages, foods, condiments (such as ketchup), gasoline, petrochemicals and hydrocarbons, water, waterbased solutions, solvent-based solutions, emulsions, and adhesives. The container  12 , cover-connector  14  and adapter  16  must be compatible with the fluid being supplied and the fluid should flow from container  12  in a similar manner as paint from a paint container  12 . 
     A paint sprayer  2  is shown in FIG.  1  and includes a body  3 , a nozzle assembly  4  secured to a front end  5  of body  3 , and a handle  6  depending from a rear end  7  of body  3 . A trigger  8  is pivotally secured to body  3  for the manual actuation of sprayer  2 . A top mounted, gravity-feed paint container  12  is mounted to body  3  via cover-connector  14  and adapter  16  near front end  5  for feeding paint to nozzle assembly  4 . An air connector  9  is connected to an air hose (not shown) for the delivery of pressurized air to nozzle assembly  4 , wherein the delivery of pressurized air is controlled by trigger  8 . 
     Compressed air from air connector  9  is delivered through an internal passage (not shown) to nozzle assembly  4  and the compressed air acts to atomize paint and deliver it through nozzle assembly  4  to spray paint  1  about a spray axis  11 . Paint  1  is delivered to nozzle assembly  4  via gravity from paint container  12 . The level of paint  1  in paint container  12  must be higher than the sprayer connection channel  13 , or else paint  1  will not feed via gravity to the nozzle assembly  4 , a condition known as starvation. 
     FIGS. 1-5 show a first embodiment of a paint supply assembly  10  of the present invention. In the first embodiment, container  12  includes a cover-connector  14  for covering container  12  and connecting it to the conduit, wherein the conduit can be a tapered hollow bore adapter  16  for connecting cover-connector  14  to sprayer  2 . Cover-connector  14  shown in FIG. 2 includes a conduit connecting region  20  comprising a fitting  34  at conduit side  17  and a container connecting region  80  at container side  15 . Conduit connecting region  20  includes a female frustoconical surface  44  for engaging with a complementary male frustoconical connecting surface  62  of adapter  16 . Frustoconical female surface  44  is angled radially outwardly at an acute angle from a cover axis  32  so that female frustoconical surface  44  of fitting  34  is complementary to tapered adapter  16 , providing for frictional connection therebetween. When cover-connector  14  is engaged with container  12  and when fitting  34  is engaged with adapter  16 , there is fluid communication between fluid container  12  and adapter  16 . 
     Container  12  includes an interior  18  for holding paint  1  and can be generally cylindrical in shape with an outlet end  26  for engaging with cover-connector  14 , such as with threading  28  on container  12  engageable with threading  30  on cover-connector  14 . Container  12  can have an interior volume of between about 8 fluid ounces and about 2.5 gallons, preferably between about 16 fluid ounces and about 2 liters, still more preferably about 1 liter. A one liter generally cylindrical container  12  has a length of about 4 inches and a diameter of about 6 inches. However, container  12  can have different proportions or geometry. Preferably, the size and shape of container  12  is conducive to the automobile refinishing industry so that sprayer  2  and paint container  12  are not unwieldy or overly heavy for an operator to handle. 
     Container  12  can be an unlined paint cup, as shown in FIG. 4, or container  12  can be lined (not shown) as disclosed in the commonly assigned, co-pending patent application Ser. No. 10/458,478 filed contemporaneously herewith, the disclosure of which is incorporated herein by reference. 
     Preferably, container  12  is made from a translucent material so that the level of paint  1  can be seen through container  12 . Both container  12  and cover-connector  14  should also be relatively durable and resistant to collapsing, be made from a relatively inexpensive material and be inexpensive to manufacture so that container  12  and cover-connector  14  can be disposable if desired, and be made from a material that is substantially unreactive to the fluid being delivered to sprayer  2 . In one embodiment, container  12  and cover-connector  14  are made from a molded plastic, such as polyethylene or polypropylene. In a preferred embodiment, container  12  and cover-connector  14  are molded from low-density polyethylene. Container  12  can be molded by any of several methods including injection blow molding, injection molding, rotational molding, suction molding, or extrusion molding. Injection blow molding is preferred because it is an inexpensive process. Cover-connector  14  also can be made by several molding methods, but preferably is made by injection molding because of its unique geometry, described below. 
     Turning to FIGS. 2 and 5, in a preferred embodiment, the interior of cover-connector  14  is shaped generally in the form of an hourglass having a waist  72 , a first lobe  74  extending from adapter side  17  outwardly at an obtuse angle from waist  72  to cover and engage with container  12 , and a second lobe  75  extending outwardly at an acute angle from waist  72  to frictionally engage generally complementary male tapered hollow bore adapter  16  for use with gravity-feed paint sprayer  2 , wherein first lobe  74  and second lobe  75  are preferably generally coaxial with one another. 
     In one embodiment, first lobe  74  forms the main part of cover-connector  14  and is generally frustoconical in shape having a cover axis  32 , wherein first lobe  74  extends from a vertex region  76  to an edge  78  at an obtuse generally frustoconical angle ù facing toward container  12 , see FIG. 2. A container connecting region  80  adjoins first lobe  74  at edge  78  on container side  15  and extends toward container  12 . Container connecting region  80  can include threads  30  for engaging with threading  28  on container  12 , wherein threads  30  are generally normal to cover axis  32 . 
     Second lobe  75  comprises an adapter connection region such as female generally frustoconical fitting  34  and is integrally connected to first lobe  74  of cover-connector  14  at vertex region  76 . Female generally frustoconical fitting  34  extends from cover-connector  14  generally axially opposite from container connecting region  80  for receiving male frustoconical connecting surface  62  of adapter  16 . Female fitting  34  is angled to open axially and radially outwardly at a predetermined angle á from cover axis  32  to a distal fitting end  82  generally defining a plane normal to cover axis  32 . Female fitting  34  is generally complementary to male adapter  16 , providing for frictional engagement between cover-connector  14  and adapter. 
     A passageway is provided between container connecting region  80  and fitting  34  of the adapter connecting region. In one embodiment, the passageway is formed by fitting  34  and frustoconical first lobe  74 , wherein paint can flow from container  12 , through container connecting region  80 , past first lobe  74 , through fitting  34  and into adapter  16 . The passageway can comprise a hole in cover-connector  14 , a passageway already formed between fitting  34  and container connecting region  80 , or a passageway that has to be formed between fitting  34  and container connecting region  80 , such as a perforable membrane  50  that is broken by adapter  16 , described below, to form the passageway. 
     In one embodiment, cover-connector  14  includes a generally cylindrical support wall  36  extending from edge  78  to a distal wall end  84 , wherein distal wall end  84  is in the same plane as distal fitting end  82 . Distal wall end  84  should extend at least to the plane of distal fitting end  82 , or farther, so that a paint shaker (not shown) can be used to agitate container  12  to mix paint  1  without deforming or damaging fitting  34 . Because distal wall end  84  extends to the plane of distal fitting end  82 , the forces exerted are distributed to fitting  34  and support wall  36 , thereby providing greater structural integrity and resistance against breaking or rupture of fluid supply assembly  10  and its parts. 
     In one embodiment, container  12  has a diameter of between about 4 inches and about 8 inches, preferably about 6 inches, and first lobe  74  extends from vertex region  76  to edge  78  from between about 2 inches to about 5 inches, preferably about 2½ inches. The obtuse angle ù of first lobe  74  may be between about 100° and about 150°, preferably about 120°. The preferred frustoconical shape of first lobe  74  helps to provide structural strength sufficient to withstand engagement with a friction-fitted component when an operator inserts and pushes adapter  16  into fitting  34 . The orientation of first lobe  74 , wherein obtuse angle ù opens toward container  12  is preferred because it helps to funnel paint into the passageway and thence to the conduit and applicator. 
     Frustoconical female surface  44  is angled from cover axis  32  at a predetermined angle acute angle á that may be between about 1° and about 7°, preferably between about 2° and about 5°, still more preferably about 3°. Angle á should be small enough to provide for a strong frictional force between male frustoconical connecting surface  62  and female frustoconical surface  44 , but should be large enough to allow for the insertion of male frustoconical connecting surface  62  into fitting  34  without difficulty. 
     The length of fitting  34  from vertex region  76  to distal fitting end  82  should be long enough to provide sufficient friction between fitting  34  and male frustoconical connecting surface  62  of adapter  16 . In one embodiment, the length of fitting  34  is between about ½ inch and about 3 inches, preferably between about ¾ inch and about 1½ inches, still more preferably about 1 inch. The inner diameter of fitting  34  at distal fitting end  82  should be large enough to easily receive male frustoconical connecting surface  62  to provide for easy engagement between cover-conmector  14  and adapter  16 . In one embodiment, the inner diameter of fitting  34  at distal fitting end  82  is between about ½ inch and about 1 inch, preferably about ¾ inch. 
     The geometry of cover-connector  14  should be chosen so that waist  72 , first lobe  74 , second lobe  75 , the engagements between fitting  34  of second lobe  75  and adapter  16  and between container connecting region  80  and container  12  are of a strength sufficient to hold container  12  and the paint  1  it contains in an operative position so that cover-connector  14  does not break during operation due to stress from container  12  and paint  1 . For example, waist  72  can be reinforced by making second lobe  74  thicker at waist  72 , as best seen in FIG. 5, to ensure that fitting  34  is strong enough to support container  12  and its contents. 
     Complementary generally fustoconical connecting surfaces  44  and  62  allow for easy engagement and disengagement of adapter  16  and cover-connector  14  simply by rotating one with respect to the other slightly, to frictionally lock or unlock adapter  16  and cover-connector  14 . 
     In one embodiment, fitting  34  includes a perforable membrane  50  across the passageway at waist  72  for keeping container  12  closed until use. Preferably, membrane  50  is radially inside of fitting  34  sealing container until membrane  50  is broken by adapter  16 , shown in FIG.  3 . 
     Continuing with FIGS. 2 and 4, cover-connector  14  frictionally connects with a conduit into paint sprayer  2 . In a preferred embodiment, the conduit is an adapter  16  for connecting between paint sprayer  2  and cover-connector  14 . Adapter  16  is preferably generally cylindrical in shape, including an adapter axis  52 , a first end  54  engageable with sprayer  2 , shown in FIG. 1, a second end  56 , and a hollow bore  24  between first end  54  and second end  56 . Adapter  16  includes a male frustoconical connecting surface  62  at the inlet into bore  24  to complement tapered fitting  34  so that adapter connecting region  20  and male frustoconical connecting region  62  can be frictionally engaged to lock adapter  16  and fitting  34  together. 
     In one embodiment, best seen in FIG. 1, first end  54  of adapter  16  includes threading  58  for engaging with the threading  60  of a sprayer connection channel  13 . Preferably, threading  58  is of a typical size and pitch for paint sprayers so that fluid supply assembly  10  can be used with any of several sprayers. In one embodiment, the outside diameter of threading  58  is between about ½ inch and about 1 inch, preferably about ¾ inch. 
     First end  54  of adapter can engage with sprayer  2  by means other than a threaded connection, including a tapered connection (not shown), a bayonet connection (not shown), a snap connection (not shown), or by first end  54  being integral with sprayer  2  so that the adapter  16  is a feed conduit into sprayer  2 . 
     Male frustoconical connecting surface  62  forms an acute angle â with respect to adapter axis  52 . In one embodiment, angle â is between about 1° and about 7°, preferably between about 2° and about 5°, still more preferably about 3° to form a self-locking taper. In a preferred embodiment, the angle â is approximately equal to the angle á of female frustoconical surface  44  so that male frustoconical connecting surface  62  complements female frustoconical surface  44  allowing for locking frictional engagement between adapter  16  and cover-connector  14 . As with angle á, angle â should be small enough to provide for tight frictional engagement, but should be large enough to allow for easy insertion of male frustoconical connecting region  62  into fitting  34 . 
     Complementary female frustoconical surface  44  of cover-connector  14  and male frustoconical connecting surface  62  of adapter  16  stay engaged with each other due to frictional forces. For example, for the embodiment shown in FIGS. 2 and 3, after adapter  16  is inserted into fitting  34 , male frustoconical connecting surface  62  engages with female frustoconical surface  44 . As adapter  16  is continued to be pushed and rotated by an operator into fitting  34 , the male frustoconical connecting surface  62  begins to slightly deform the female frustoconical surface  44  of fitting  34 , creating a strong frictional force between adapter  16  and cover-connector  14 . This strong frictional force effectively seals adapter  16  into tapered outlet  20  to prevent leaking of paint. 
     The male frustoconical connecting surface  62  and complementary female frustoconical surface  44  also allow for releasable engagement between adapter  16  and fitting  34 . In order to release adapter  16  from engagement with cover-connector  14 , an operator simply has to rotate adapter  16  and cover-connector  14 , one with respect to the other, in the opposite rotational direction as when the operator frictionally engaged frustoconical surface  44  and  62 , as described below. 
     In one embodiment, adapter  16  includes a sharp edge or perforator  64  at second end  56  which acts as a bayonet for breaking perforable membrane  50  when adapter  16  is engaged with tapered outlet  20 , as shown in FIG.  3 . 
     Adapter  16  also can include a filter  66  in bore  24  to filter impurities, such as dust or other particulates, from flowing into sprayer  2  so that the impurities will not be applied to the surface being painted. Filter  66  is preferably removable, such as with a small handle  68 , so that filter  66  may be replaced if it becomes worn or soiled. An example of a filter that can be used is the model KGP-5-K5 filter manufactured by ITW DeVilbiss Automotive Refinishing. 
     Turning to FIG. 5, adapter  16  also can include a tool engaging portion  70 , which can have a cross-sectional shape adapted to be engaged by a tool to aid in rotation of adapter  16 , such as a wrench (not shown) to install or uninstall adapter  16  from engagement with sprayer  2 . Tool engaging potion  70  can have a cross-sectional shape such as a hexagonal shape for easy engagement with a tool. 
     Adapter  16  preferably is manufactured from a metal or other durable material that is substantially unreactive and resistant to corrosion by the fluid passing through adapter  16 . Preferably, adapter  16  is made from a metal so that adapter  16  will be durable and can be reused multiple times without needed to be replaced. In one embodiment, adapter  16  is made from aluminum, but it can be made from other metals or alloys including steel, zinc or powder metals. A metal adapter  16  can be made by several methods include machining, die casting, investment casting, precision casting or powdered metallurgical methods. Alternatively, adapter can be made from a plastic, such as polyethylene or polypropylene, or other engineered plastics by injection molding or other methods. 
     Although adapter  16  is shown as being one generally cylindrical piece, it is envisioned that adapter  16  can have other configurations, such as an adjustable adapter that allows the orientation of container  12  to be changed to ensure that paint  1  will flow into sprayer  2 . An example of an adjustable adapter is disclosed in the commonly assigned, co-pending patent application Ser. No. 10/458,548 filed contemporaneously herewith, the disclosure of which is incorporated herein by reference. 
     Turning to FIGS. 6 and 7, a second embodiment of the fluid supply assembly  10   b  of the present invention is shown. In the second embodiment, fluid supply assembly  10   b  does not include an adapter between the cover-connector and the sprayer, and cover-connector  14   b  engages directly with the sprayer conduit. 
     Container  12   b  includes a cover connecting region  88  that is tapered toward outlet end  26   b  so that the wall of container  12   b  is thinner at a top end  40  than at a bottom end  42 , forming a tapered surface  44   b . In one embodiment, cover connecting region  88  is on a male frustoconical connecting surface  44   b , forming a male frustoconical connecting surface  44   b  that converges toward outlet end  26   b , wherein male frustoconical connecting surface  44   b  forms an acute predetermined angle ã with respect to container axis  32   b . In one embodiment, angle ã is between about 1° and about 7°, preferably between about 2° and about 5°, still more preferably about 3° to form a self-locking tapered container outlet. In a preferred embodiment, male frustoconical connecting surface  44   b  complements a generally frustoconical female surface  62   b  on cover-connector  14   b , described below. 
     Continuing with FIG. 6, cover-connector  14   b  of the second embodiment forms a mushrooming shape so that cover-connector  14   b  acts to both cover container  12   b  and to connect container  12   b  to a conduit of a paint sprayer. Cover-connector  14   b  includes a conduit side  17   b  with a conduit connecting region  86  having threads  58  for engaging a conduit and a container side  15   b  having a container connecting region  80   b  with a female frustoconical surface  62   b  for frictionally connecting to male frustoconical connecting surface  44   b . Cover  14   b  also includes a bore or passageway  24   b  between conduit connecting region  86  and container connecting region  80   b.    
     Continuing with FIG. 6, in one embodiment, cover-connector  14   b  is generally frustoconical in shape having an axis  32   b , wherein cover-connector  14   b  extends from a vertex region  76   b  to an edge  78   b  at an obtuse generally frustoconical angle ä facing toward container  12   b . A conduit connecting region  86  is included at first end  54   b . In one embodiment, conduit connecting region  86  includes threads  58   b  for engaging with threading on the sprayer, wherein threads  58   b  are preferably generally normal to adapter axis  32   b . Cover-connector  14   b  also includes a tapered container connecting region  80   b  that complements cover connecting region  88  for engaging with container  12   b . Container connecting region  80   b  adjoins cover-connector  14   b  at edge  78   b  and extends generally toward container  12   b . Container connecting region  80   b  includes a female frustoconical surface  62   b  that compliments male frustoconical connecting surface  44   b  of container  12   b , wherein female frustoconical surface  62   b  is angled from adapter axis  32   b  at an acute predetermined angle è so that female flustoconical surface  62   b  is complementary to male frustoconical connecting surface  44   b  of container  12   b  to provide for frictional engagement therebetween. 
     In one embodiment, angle è is between about 1° and about 7°, preferably between about 2° and about 5°, still more preferably about 3°. In a preferred embodiment, the angle è of adapter female frustoconical surface  62   b  is approximately equal to the predetermined angle ã of male frustoconical connecting surface  44   b  of container  12   b  so that female frustoconical surface  62   b  complements male frustoconical connecting surface  44   b  allowing for locking frictional engagement between cover-connector  14   b  and container  12   b.    
     The method that an operator uses to connect a fluid container  12  to a fluid applicator  2  includes the steps of providing a conduit, such as hollow bore adapter  16 , in fluid communication with fluid applicator  2 , providing a fluid container  12 , wherein one of the container  12  and the conduit include a male frustoconical connecting surface  62  and the other of the container  12  and the conduit includes a threaded connecting surface  28 , providing a cover-connector  14  having a conduit side  17  with a conduit connecting region  20 , a container side  15  with a container connecting region  80 , and a passageway between the connecting regions  20 ,  80 , wherein one of the connecting regions  20 ,  80  has a female frustoconical surface  44  having an acute frustoconical angle complementary to male frustoconical connecting surface  62 , and wherein the other of the connecting regions  20 ,  80  has a threaded portion  30  complementary to the threaded connecting surface  28 , threading connecting threaded portion  30  with threaded connecting surface  28 , and engaging male frustoconical connecting surface  62  with female frustoconical surface  44  and rotating male frustoconical connecting surface  62  and female frustoconical surface  44  with respect to one another for frictional connection therebetween. 
     An operator uses fluid supply assembly  10  by loading a desired color of paint  1  and any desired tinting additives or solvents into a container. If container  12  of FIGS. 1-5 is used, cover-connector  14  is engaged with container  12 , such as by engaging container threading  28  with cover threading  30 . Container and cover-connector  14  can then be placed in a paint shaker (not shown) to ensure that paint  1  and any tinting additives or solvents are thoroughly and evenly mixed. Perforable membrane  50  in cover-connector  14  prevents paint  1  from spilling out of container  12 . If container  12   b  of FIGS. 6 and 7 is used, container  12   b  is engaged with cover-connector  14   b , described below, after loading paint. 
     In FIGS. 1-5, engaging adapter  16  with container  12  includes inserting male frustoconical connecting surface  62  into fitting  34  so that male frustoconical connecting surface  62  of adapter  16  is engaged with female frustoconical surface  44  of fitting  34 . While adapter  16  is pushed into fitting  34 , perforator  64  cuts through membrane  50 , forming the passageway so that adapter bore  24  will be in fluid communication with interior  18  of container  12 . The operator continues pushing adapter  16  in an axial direction into fitting  34  until adapter  16  stops, at which point the operator continues to push in an axial direction while rotating adapter  16  with respect to container  12  and cover-connector  14 , or vice versa, until male frustoconical connecting surface  62  of adapter  16  is forcefully and rotationally engaged with female frustoconical surface  44  of receptacle. In one method, the operator rotates adapter  16  or container  12  between about 5° and about 90°, preferably between about 10° and about 15° with respect to the other. As adapter  16  is rotated, male frustoconical connecting surface  62  slightly deforms female frustoconical surface  44  to create a tight frictional seal between adapter  16  and container  12 . Adapter male frustoconical connecting surface  62  and female frustoconical surface  44  are not threads, so it does not matter which direction adapter  16  and container  12  are rotated. Either direction will cause male frustoconical connecting surface  62  and female frustoconical surface  44  to frictionally lock against each other to form a tight frictional seal. 
     In the embodiment of FIGS. 6 and 7, after container  12   b  is loaded with paint  1 , male frustoconical connecting surface  44   b  at outlet end  26   b  of container  12   b  is inserted into female frustoconical surface  62   b  of cover-connector  14   b  and container  12   b  and cover-connector  14   b  are rotated with respect to one another, in order to frictionally engage and lock male frustoconical connecting surface  44   b  with female frustoconical surface  62   b . As with FIGS. 1-5 described above, it does not matter which direction the operator rotates container  12   b  or cover-connector  14   b  because male frustoconical connecting surface  44   b  and female frustoconical surface  62   b  are not threads. 
     The operator then engages first end  54  of adapter with sprayer  2 , such as with adapter threading  58  and connector channel threading  60 . Sprayer  2  is turned upside down, generally opposite to what is shown in FIG. 1, so that paint  1  will not spill out of container through adapter  16 , and first end  54  is inserted into connection channel  13  of sprayer  2 . Either fluid supply assembly  10  or sprayer  2  is rotated so that adapter threading  58  engages with connector channel threading  60 . Sprayer  2  can now be used to apply paint  1  to a surface. 
     The operator can change the order of the steps to suit their own needs and preferences. For example, the operator could engage adapter  16  with sprayer  2  first, then engage male frustoconical connecting surface  62  of adapter  16  with female frustoconical surface  44  of fitting  34 , then engage cover-connector  14  with container  12 . All connections are to be made so that paint  1  will flow, without leaking, from container  12 , through adapter  16 , and into sprayer  2 . 
     After the operator is finished spraying paint, sprayer  2  and container  12  are again turned upside down, generally opposite to what is shown in FIG. 1, and cover-connector  14  and container  12  are disengaged from adapter  16 . In order to disengage tapered adapter  16  from cover-connector  14 , the operator simply rotates one or the other in the opposite direction as when the operator engaged adapter  16  and container  12 . For example, if the operator rotated adapter  16  in a clockwise direction relative to container  12  for engagement, the operator would rotate adapter  16  in a counterclockwise direction relative to container  12  for disengagement. Disengaging container  12   b  from cover-connector  14   b  of FIGS. 6 and 7 is accomplished in a similar manner. 
     The present invention provides a tight and strong seal for a fluid supply assembly between a conduit and a container via a cover-connector that is easy to engage and disengage. A cover-connector for covering and connecting a fluid supply container to a conduit is provided, wherein one of the container and the conduit has a male frustoconical connecting surface and the other one of said container and said conduit has a threaded connecting surface. The novel cover-connector comprises a conduit side with a conduit connecting region, a container side with a container connecting region, and a passageway between the connecting regions, wherein one of the connecting regions has a female frustoconical surface having an acute frustoconical angle complementary to the male frustoconical connecting surface for frictional connection therebetween, and wherein the other of the connecting regions has a threaded portion complementary to the threaded connecting surface for threaded connecting therebetween. 
     While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific exemplary embodiments and methods herein. The invention should therefore not be limited by the above described embodiments or methods, but by all embodiments and methods within the scope and spirit of the invention.