Abstract:
A liquid applicator having a collapsible liquid reservoir with an elongated outer chamber wall having a characteristic length, and a liquid delivery piston having a length substantially equal to the characteristic length, wherein the piston is telescopically received in the outer chamber wall, and an elongated intermediate chamber wall having a length substantially equal to the characteristic length and wherein the intermediate chamber wall is telescopically received in the outer chamber wall located circumferentially intermediate the piston and the outer chamber wall, wherein the liquid reservoir and piston may be telescopically expanded to either a fully expanded condition wherein the combined length of the liquid reservoir and piston is about three times the characteristic length or a partially expanded intermediate condition wherein the combined length of the liquid reservoir and piston is substantially less than half the length of the liquid reservoir and piston in the fully expanded condition.

Description:
FIELD OF THE INVENTION 
   The present invention relates to the field of liquid coating applicators including, but not limited to painting equipment. More specifically, the invention relates to devices and methods for applying liquids including, but not limited to, paint and similar coatings (such as liquid stain) using an internally-fed manual powered roller or other liquid coating applicator head. The present invention is suitable for applying water or other liquids in the removal of wallpaper. 
   BACKGROUND OF THE INVENTION 
   Prior art paint applicators include conventional rollers, pad applicators and brushes. One advance in the prior art included a single stage internal feed paint roller, exemplified by U.S. Pat. No. 4,732,503 and Des 417,552, the entire contents of each of which are hereby incorporated by reference. Such internal feed paint applicators have found commercial success through wide acceptance and use by consumers. However, such applicators have a deficiency in that they are so long that they cannot be conveniently used in confined spaces such as closets. The paint reservoir and piston extend to such a length as to be impractical for use in confined spaces. 
   SUMMARY OF THE INVENTION 
   The present invention is an improvement over the relatively long length prior art internal feed liquid applicators in that it provides a liquid applicator useable in a shortened configuration or in an elongated configuration, without requiring any extra parts or special assembly or disassembly efforts on the part of the operator. The liquid applicator of the present invention is unlike the prior art applicators in that it includes a telescopically collapsible liquid reservoir. More particularly, the present invention further includes an elongated outer chamber wall having a characteristic length, a liquid delivery piston having a length substantially equal to the characteristic length, with the piston telescopically received in the outer chamber wall, and an elongated intermediate (or inner) chamber wall having a length substantially equal to the characteristic length. In the present invention, the intermediate chamber wall is telescopically received in the outer chamber wall and located circumferentially intermediate the piston and the outer chamber wall. The liquid reservoir and piston may be telescopically expanded either to a fully expanded condition wherein the combined length of the liquid reservoir and piston is about three times the characteristic length, or a partially expanded intermediate condition wherein the combined length of the liquid reservoir and piston is substantially less than half the length of the liquid reservoir and piston in the fully expanded condition. 
   The liquid applicator of the present invention may have the liquid reservoir and piston telescopically compressed to about one third the length of the liquid reservoir and piston in the fully expanded condition. 
   While a preferred embodiment is disclosed, other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes an illustrative embodiment of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a prior art manually operated single piston internal feed paint roller applicator, with a roller head shown in phantom. 
       FIG. 1A  is a perspective view of the prior art applicator of  FIG. 1 , except on a reduced scale and showing a piston fully telescoped out of a reservoir in the handle of the applicator. 
       FIG. 2  is a perspective view of the dual piston liquid applicator assembly of the present invention with the roller head shown in phantom and with the handle reservoir fully telescopically extended. 
       FIG. 3  is a perspective view of the handle reservoir of  FIG. 2  fully telescopically collapsed. 
       FIG. 4  is a perspective view of the handle reservoir of  FIG. 2  in a first partially telescopically extended condition with only one piston extended. 
       FIG. 5  is a perspective view of the handle reservoir of  FIG. 2  in a second partially telescopically extended condition with both pistons extended. 
       FIG. 6  is an exploded view of the handle reservoir of  FIG. 2 . 
       FIG. 7  is an enlarged view of certain parts of the handle assembly of  FIG. 6  showing details of the prior art roller head attachment collar and fill tube subassembly. 
       FIG. 8  is an enlarged view of certain parts further exploded from the handle assembly of  FIG. 6  showing details of an intermediate chamber wall interior end cap subassembly. 
       FIG. 9  is an enlarged view of certain parts further exploded from the handle assembly of  FIG. 6  showing details of an end cap subassembly of a piston. 
       FIG. 10  is an enlarged view of an end knob and an intermediate wall retaining ring. 
       FIG. 11  is an alternative embodiment for a threaded cylinder end ring useful for removable attachment of the inner piston to the intermediate chamber. 
       FIG. 12  shows a mating threaded retaining ring threadably receivable on the threaded cylinder end ring of  FIG. 11 , along with an alternative rear knob. 
   

   DETAILED DESCRIPTION 
   Referring to the Figures, and most particularly to  FIGS. 1 and 1A , a prior art paint applicator  20  may be seen. This applicator is sold by Wagner Spray Tech Corporation under the PAINT MATE trademark. Applicator  20  is shown in a fully collapsed state in  FIG. 1  and (in a reduced scale) in a fully extended state in  FIG. 1A . Because applicator  20  has a non collapsible paint reservoir  22 , the fully extended state is generally twice the characteristic length of the applicator reservoir in the fully collapsed state. Applicator  20  also has a paint applicator head such as a roller head assembly  28 . Alternatively, a paint pad assembly (not shown) may be used in place of the roller head assembly  28 . 
   In operation, a user fills the reservoir  22  by drawing a piston  24  back to load the reservoir with paint while the inlet valve  26  is in communication with a fill tube (not shown) connected to a source of paint, such as a conventional one gallon paint can or container (not shown). When the reservoir  22  is filled with paint the applicator can be unwieldy when a user desires to paint a surface in a confined space, such as a closet. 
   Another prior art device is a short internal feed paint applicator, offered for trim painting applications, such as the applicator sold by the assignee of the present invention under the trademark TRIM-IT. Such short paint applicators are insufficient to reach many surfaces that a user may desire to paint, and as such, users heretofore have needed to purchase both a long handled paint applicator and a short internal feed paint applicator if they desire to paint both hard to reach (distant) surfaces and surfaces in confined spaces. 
   The present invention provides an advantage over the prior art by providing a single applicator that is capable of painting (or applying other liquid material) to both distant surfaces and surfaces in confined spaces because of a unique collapsible liquid reservoir that can be used in a relatively short configuration as well as in a relatively long configuration, without disassembly or special adaptation by a user. 
   Referring now to  FIGS. 2 and 3 , a liquid applicator  30  of the present invention may be seen. Applicator  30  has a collapsible liquid reservoir  32 , which permits applicator  30  to conveniently be used in confined spaces such as closets, by partially collapsing the reservoir  32 , as shown in  FIG. 4  or  5 . In the fully collapsed condition as shown in  FIG. 3 , the liquid reservoir  32  of the present invention has the added advantage of requiring less storage space than the prior art applicator  20 . The applicator  30  may use the same paint applicator head such as the roller head assembly  28  or a paint pad assembly (not shown), or another paint applicator head such as a brush assembly (not shown). As a still further alternative, another liquid applicator head may be attached to the applicator  30 , to remove wallpaper, for example. 
   As may be seen in  FIGS. 2 and 3 , the applicator  30  of the present invention has a first or outer cylinder  34  forming an outer chamber wall  36 , and an intermediate cylinder or chamber  38  formed by an intermediate chamber wall  40  and an inner piston  42 . The intermediate cylinder  38  may also be characterized as forming an intermediate piston  44  with respect to the first cylinder  34 , and thus the overall design may be characterized as a double piston design internal feed paint (or liquid) applicator. 
   Referring now also to  FIGS. 4 and 5 , the collapsible liquid reservoir  32  for liquid applicator  30  (shown in  FIGS. 3 ,  4  and  5  without the paint applicator head) is shown in  FIGS. 4 and 5  in two alternative “intermediate” conditions between a fully collapsed condition (shown in  FIG. 3 ) and a fully extended condition (shown in  FIG. 2 ). In  FIG. 4 , the intermediate cylinder  38  is telescopically collapsed within the outer cylinder  34 , and the inner piston  42  is telescopically extended therefrom. In  FIG. 5 , the intermediate cylinder  38  is telescopically extended from the first or outer cylinder  34 , and the inner piston  42  is telescopically collapsed within the intermediate cylinder  38 . From a user&#39;s operational viewpoint, each of the two intermediate conditions are substantially equivalent. It is to be understood that it is not necessary to intentionally or purposefully manually arrange or move the various parts of the applicator  30  from the position shown in  FIG. 2  to either of the intermediate conditions of  FIGS. 4 and 5 , but that the parts of the applicator  30  of the present invention may assume either of the intermediate conditions during operation by themselves. It is to be further understood that other, “blended” intermediate conditions with the inner piston  42  and the intermediate cylinder  38  partially telescopically extended with respect to each other may occur during operation, without user intervention. In other words, the relative telescoping movement of (and between) the inner piston and the intermediate cylinder may occur in any fashion without affecting the operation of the present invention. 
   With the double piston design of the present invention, the user will preferably collapse the collapsible reservoir  32  completely (to the condition shown in  FIG. 3 ) prior to filling. To fill the unit, the user then pulls back on a rear knob  46  to load the reservoir  32  with paint or other liquid to the extent desired. One or both of the outer and intermediate cylinders  34 ,  38  fill simultaneously or in sequence, which may occur in a random or quasi-random fashion. It is to be understood that it does not matter which fills first or how much liquid each fills with at any given time. The outer and intermediate cylinders  34  and  38  act together seamlessly, and the user does not have to think about or try to control which is filling or when. As with prior art products, if the user pulls the piston out halfway (in air) first, that air will remain in the reservoir and may have to be pushed out (if the roller head is positioned above the reservoir) before applying the liquid contained in the reservoir. It is intended that the user will always begin with the collapsible liquid reservoir  32  in the fully collapsed position (as shown in  FIG. 3 ) with the present invention. After being at least partially filled with a liquid (such as paint or stain) the collapsible reservoir  32  of the present invention is preferably gradually telescopically collapsed in steps or stages as the user urges the liquid from the reservoir to the applicator head during operation. One important advantage of the present invention is that, because of the unique double piston, overall size and collapsed length is very short, while the ability to provide extended reach remains relatively long. This allows more convenient use in a tight spaces such as hallways by partially filling the unit, while still being able to reach up to the ceiling using the same tool with a complete fill. Maximum fill capacity is preferably generally equivalent to prior art devices as shown in  FIGS. 1 and 1A . 
   Referring now most particularly to  FIGS. 6-10 , the various parts of the present invention may be seen in more detail.  FIG. 6  shows an overall exploded view, and each of  FIGS. 7-10  show enlarged fragmentary exploded views of the parts shown in  FIG. 6 . 
   As shown in  FIG. 7 , the present invention may use a retainer  48  that is the same or similar to what is used in the prior art to retain the applicator head. Retainer  48  is preferably received and permanently secured to a cover  50  and an end fitting  52 . End fitting  52  is preferably permanently secured to the outer chamber wall  34  via an integral collar  54 . Retainer  48  also may have a duckbill valve  56  and a retainer disk  58  removably secured thereto by a threaded cap  60 . 
   Turning now most particularly to  FIG. 8 , the intermediate chamber wall  40  in the form of a right circular cylinder preferably has an intermediate chamber or piston end cap  62  permanently secured thereto. A pair of O-rings  64  seal the piston end cap  62  to an interior cylindrical surface of the outer chamber wall  36 . Piston end cap  62  has an opening  66  in an end wall  68  thereof. Opening  66  provides for fluid communication between the interior of outer cylinder  34  and the interior of intermediate chamber  44 . 
   Referring now to  FIG. 9 , an intermediate retaining ring  70  is slidingly received over the intermediate chamber wall  40  and is preferably permanently secured to the outer chamber wall  36  (see  FIG. 6 ). An inner piston end cap  72  is preferably permanently secured to inner piston  42 , and seals against an inner surface of intermediate chamber wall  40  using a pair of piston O rings  74 . Inner piston end cap  72  preferably has a solid end wall  76 . 
   In  FIG. 10 , a piston retaining ring  78  is slidingly received over inner piston  42  and is preferably permanently secured to the intermediate chamber wall  40  (see  FIG. 6 ). Rear knob  46  is preferably permanently secured to a proximal end of the inner piston  42 . Intermediate retaining ring  70  prevents separation of the intermediate chamber  44  from the outer chamber  34  because of interference between a bore in intermediate retaining ring  70  and the intermediate piston end cap  62 . Piston retaining ring  78  prevents separation of inner piston  42  from the intermediate chamber  38  because of interference between a bore in ring  78  and inner piston end cap  72 . It is to be understood that rings  70  and  78  may be permanently secured to their respective chambers, or they may be forced onto their respective cylindrical walls with a force or interference fit, if desired. 
   Referring now most particularly to  FIGS. 11 and 12 , in an alternative arrangement, ring  78 ′ may be internally threaded and an externally threaded cylinder end ring  80  may be permanently secured to the intermediate cylindrical wall  40 . Such an arrangement provides removable attachment of the inner piston  42  to the intermediate chamber  38  for cleaning. A similar or identical arrangement may be provided between the outer cylindrical wall  36  and the intermediate cylindrical wall  40  by adding an externally threaded end ring corresponding to ring  80  on the end of the outer cylindrical wall, and providing ring  70  with mating internal threads, to allow selective separation and attachment of the intermediate chamber  38  with respect to the outer chamber  34 .  FIG. 12  also shows an alternative rear knob  82  useful for urging the inner piston towards the applicator head to deliver liquid from the telescoping reservoir to the applicator head. 
   It is to be understood that to paint (or apply other liquid) with extended reach, the present invention is preferably operated from the fully extended condition to a partially collapsed condition, giving the same or similar reach as is available with the prior art device, while permitting a user to selectively paint (or apply other liquid) in a confined space by partially filling the reservoir and fully telescopically collapsing the reservoir  32  of the present invention. 
   It may thus be seen that the intermediate portion of the collapsible reservoir of the present invention may be considered either an intermediate chamber or intermediate piston when the inner piston  42  is not fully collapsed within the intermediate chamber wall  40 . This is because liquids including (but not limited to) paint and similar coating materials are generally incompressible and urging the rear knob  46  towards the roller head assembly  28  will deliver liquid from the outer chamber  34  to the roller because of pressure from the inner piston and liquid (if any) in the intermediate chamber  44 . 
   Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.