Power painting unit
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a continuation-in-part of application Ser. No. 894,889, filed Aug. 8, 1986, now abandoned and of application No. 06/943,886, now abandoned, filed 12/19/86. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a power painting unit for supplying paint to a paint applicator from a paint receptacle, such as a paint can. 
     2. Description of the Prior Art 
     Power painting units including applicating rollers are known wherein a power unit pumps paint from a paint reservoir through a tube to a roller or the like. In some of the known power painting units, the paint reservoir is pressurized to force paint to the applicator. A problem is presented by the pressurization of the paint reservoir in that the proper pressure seal is difficult to achieve, and that there is a risk of over-pressurization of the reservoir. Furthermore, the paint reservoir must be depressurized prior to changing the paint. 
     SUMMARY OF THE PRESENT INVENTION 
     A power painting unit according to the principles of the present invention includes a power base having generally a C configuration within which is mountable a paint reservoir, such as a paint can. The C-shaped power base has a hinged top for easy insertion and removal of the paint reservoir cans, and includes an inlet dip tube mounted for movement with the hinged top so that the inlet tube extends into the reservoir when the top is in a down position and is removed from the paint reservoir when the hinged top is in the up position. The hinged top of the unit is lockable in the down position to ensure proper operation and to prevent paint spillage. The hinged top of the unit includes a convenient rest for a handle portion of a paint applicator, the rest being shaped to function as a carrying handle for the entire power painting unit. The carrying handle allows the powered paint unit to be easily carried from place to place, even when a paint can is mounted therein. 
     A variable pressure shut-off valve is provided in the unit to prevent excessive pressure build-up, the valve preferably being controlled by a user operable control which also serves as an on/off switch for the power painting unit. Thus, the unit is turned on and off and the pressure regulated with a single control. The on/off and pressure regulation switch controls a suction pump that draws paint from the paint reservoir, eliminating the requirement of pressuring the paint reservoir. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a powered paint applicator unit according to the principles of the present invention; 
     FIG. 2 is a plan view of the power base portion of the paint applicator unit shown in FIG. 1; 
     FIG. 3 is a side elevational view of an applicator handle of the applicator unit of FIG. 1, and having a portion of the casing removed therefrom; 
     FIG. 4 is a cross section of the base portion of the applicator unit along line IV--IV of FIG. 2; 
     FIG. 5 is a cross section generally along the line V--V of FIG. 4 showing a pump apparatus and a valve of the present invention; 
     FIG. 6 is a side elevational view of a valve arrangement and power switch of the present paint applicator; 
     FIG. 7 is a front elevation of the valve arrangement and power switch shown in FIG. 6; and 
     FIG. 8 is a side elevational view, partially in cross section, of the power base portion of the present invention showing the top in an open position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring first to FIG. 1, a powered paint applicator unit indicated generally at 10 includes a power base 12 and an applicator handle 14 connected thereto by a flexible tube 16. The power base 12 is adapted for receiving a liquid reservoir, such as a paint can PC shown by dotted outline. The power base 12 is formed by three portions, a first, lower portion 18 upon which the paint can PC rests, an upright portion 20 extending vertically from the lower portion 18, and a third top portion 22 projecting laterally over the lower portion 18 from an upper end 24 of the upright portion 20. The lower portion 18 includes a paint can receiving surface 26 at the top thereof with a rim 28 extending substantially therearound and having a diameter slightly larger than that of a standard size paint can. An intake, or dip, tube 30 extends from the top portion 22 downwardly to just above the paint can receiving surface 26. 
     The flexible tube 16 is connected to the upright portion 20 of the power base 12 by a connector 32, such as a threaded connector. The other end of the flexible tube 16 is connected to a first end 34 of the applicator handle 14 by a second connector 36, which may also be a threaded connector. At an opposite end 38 of the applicator handle 14 is connected a roller attachment 40 by a threaded sleeve or other locking connector 42. Although a roller-type applicator is shown, a variety of other paint applicator attachments are also possible. 
     The applicator handle 14 is shown resting on the top portion 22 in a recess formed in a combined lift handle and applicator handle rest 44. A trough-shaped recess in the lift handle/rest 44 receives the applicator handle 14 when the applicator 40 is not in use. A recess 46 is provided in the top portion 22 beneath part of the lift handle/rest 44 so that a user&#39;s hand may be grasped therearound for lifting and carrying the paint applicator unit 10. Thus, the present applicator unit 10 may be moved about by the conveniently located lift handle/rest 44 while the applicator is resting therein so that only a single hand is required. Furthermore, no additional elements are required for holding the roller attachment 40 when not in use. 
     In the top view of FIG. 2, the lift handle/rest 44 extends across the top of both the circular top portion 22 and the upright portion 20. The top portion 22 has substantially the same diameter as the lower portion 18 and, thus, covers the top of an open paint can PC placed in the power base 12. A shaped opening 48 in the lift handle/rest 44 receives a trigger of the applicator handle 14, which will be described hereinafter. A semicircular flange 50 is mounted in the trough-shaped lift handle/rest 44 to receive a constricted portion of the applicator handle 14 and, thereby, prevent relative movement. The location of the intake tube 30 extending downwardly from the top portion 22 can be seen in dotted outline, as can the generally oval configuration of the recess 46 for receiving the hand of a user during carrying of the applicator unit 10. 
     A preferred embodiment of the paint applicator unit 10 includes an applicator handle 14 as shown in FIG. 3. The applicator handle 14 includes a casing 52, a portion of which has been removed to reveal the internal workings thereof. A flexible handle conduit 54 extends along the length of the applicator handle 14 and provides a flow path between the tube 16 and the roller attachment 40 or other paint applicator attachment. In one embodiment, the flexible conduit 54 is covered by a mesh-like covering to provide strength and durability, particularly at a pinched portion thereof. 
     A trigger 56 extends outwardly through an opening 58 in the casing 52 of the applicator handle 14. The trigger 56 fits into the correspondingly-shaped opening 48 in the lift handle/rest 44 when the applicator handle 14 is placed therein. The trigger 56 is at one end of a pinch lever 60, the other end of which includes a pinch member 62 which is pressed against a portion of the flexible handle conduit 54 to restrict the flow therethrough. The pinch lever 60 is mounted for pivotal movement about a pivot axis 64 within the casing 52. The pinch member 62 presses a portion of the handle conduit 54 against an inner wall 66 of the casing 52, that portion of the inner wall 66 against which the conduit 54 is pressed advantageously being thicker than the rest of the handle casing 52. 
     Beneath the pinch member 62 is pivotally mounted a beveled cam portion 68 of a dog 70. The beveled cam portion 68 abuts the underside of the pinch member 62 and slides thereon somewhat as the trigger 56 is operated. A compression spring 72 is mounted between the cam portion 68 to bias the pinch member 62 upwardly against the flexible conduit 54. A second portion 74 of the dog 70 abuts the flexible handle conduit 54 for stability, yet does not significantly restrict flow therethrough. As the trigger 56 is operated, the dog 70 pivots about a pivot axis 76 and the pinch member 62 opens and closes the flow path through the handle conduit 54. 
     A trigger lock 78 is slideably mounted in the handle casing 52 opposite the trigger 56. A hook 80 extending from the trigger lock 78 engages a hook 82 on the trigger 56 when the trigger 56 is operated to an open flow position and the trigger lock 78 is slid into a locking position. A compression spring 84 biases the trigger lock 78 to an unlocked position so that the trigger 56 may be unlocked simply by pressing thereagainst, thereby enabling the spring 84 to slide the trigger lock 78 to the unlocked position. Thus, the trigger lock 78 enables the trigger 56 to be held in an open flow position during painting without being constantly gripped by the user of the present device. Various fastener receiving means 86 are provided in the handle casing 52 to receive fasteners, such as screws (not shown), which hold the two halves of the handle casing 52 together. A constricted portion 88 is provided in the handle 14 to receive the flange 50. 
     In FIG. 4, a cross section of the power base 12 is shown including the intake tube 30 extending from the top portion 22 to near the bottom of a paint can PC. The top portion 22 is connected to the upper end 24 of the upright portion 20 by a hinge 90. The hinge 90 enables the top portion 22 to be pivoted upwardly for easy insertion and removal of paint cans PC, as will be described more completely in conjunction with FIG. 6. 
     A locking mechanism indicated generally at 92 holds the top 22 in a closed position for carrying and for securely retaining paint cans PC in the base 12. The locking mechanism 92 is operated by an external, manually operable knob 94. The knob 94 turns a shaft 96 that is connected to an arcuate tang engaging portion 98 that securely engages a depending tang 100 extending downwardly from the top portion 22. The arcuate engaging portion 98 has an inner surface 102 of decreasing radius so that, as the knob 94 is turned in a first direction, the decreasing radius of the inner surface 102 exerts an increasing downward force on the depending tang 100 to hold a paint can PC under the top portion 22 and to lock the top 22 in a closed position for carrying and the like. To release the top 22, the knob 94 is turned in a second, opposite direction until the arcuate engaging portion 98 no longer is over the tang 100. The top 22 may thereafter be pivoted upwardly to an open position. An upper rim 104 is provided around an underside of the top 22 to retain paint cans PC thereunder when the top 22 is locked in the down position and to prevent paint spills. 
     The intake tube 30 is connected to the top 22 at an elbow 106 mounted therein, which in turn is connected to a flexible connector tube 108 that extends from the top 22, down the upright portion 20 and is connected at a lower end thereof to a valve 110. The valve 110 is connected to a pump 112 which generates a flow of paint, which is forced from the power base 12, through the threaded connector 32 and the flexible tube 16, and to the applicator 40. The pump 112 is driven by a motor 114 through a gear arrangement 116. The operation of the motor 114 is controlled through a microswitch 118 that is operated by turning a control knob 120. The knob 120 enables a user to switch the motor 114 on and off. 
     The pump 112, which is a peristaltic pump, is shown in more detail in FIG. 5, including a pump housing 122. A drive shaft 124 of the motor 114 is connected by a gear 125 to a concentric gear pair 126, which in turn drives a gear 128. The gear 128 has a shaft portion 130 extending through the pump housing 122 to a centrally disposed internal gear 132. Upper and lower three-armed spiders 134 are freely movable about the shaft 130, each arm of the spiders 134 having mounted thereon a planetary gear 136 in engagement with the gear 132. A flexible pump tube 138 is looped within the pump housing 122 and is pinched thereagainst by the planetary gears 136. 
     As the motor 114 drives the gear arrangement 116, the internal gear 132 causes the planetary gears 136 to rotate on the ends of the three-armed spider 134 which causes the planetary gears 136 to move in a circle within the pump housing 122. As the planetary gears 136 move within the pump housing 122, they sequentially pinch the pump tube 138 to generate a fluid flow thorugh the pump tube 138. 
     A portion of the valve 110 can be seen in FIG. 5 connected between an output tube 140 of the pump 112 and the threaded sleeve 32 for connection to the tube 16. The valve 110 includes a valve housing 142 to which are mounted the connector tube 108, the sleeve 32, the pump output tube 140, and an input end 144 of the pump tube 138. In the valve housing 142 is a flexible diaphragm 146 against which is pressed a plunger 148 for movement with the diaphragm 146. The diaphragm 146 is held in place by a diaphragm bracket 150. 
     The valve 110 is shown in further detail in FIG. 6. A through passage 152 is provided through the valve housing 142 for communication between the pump outlet 140 and the threaded connector 32. The through passage 152 includes a pressure sensing chamber 154, the top of which is formed by the flexible diaphragm 146. As pressure at the output of the pump 112 changes, the diaphragm 146 flexes, causing the plunger 148 to be moved vertically. The plunger 148 extends from the bottom of a valve frame 156, the top of which is adjacent the switch 118 so that vertical movement of the plunger 148 and valve frame 156 operates the switch 118. 
     With reference to both FIGS. 6 and 7, the frame 156 includes a centrally disposed spindle 158 around which is mounted a compression spring 160 and over which is slideably mounted a vertically movable sleeve 162. Extending through an opening in the valve frame 156 is a shaft 164 mounted in the upright portion 20 for rotation with the knob 120. Mounted for rotation with the knob 120 is a cam 166 which abuts a cam follower 168 on the sleeve 162. In a preferred embodiment, the cam follower 168 includes a ridge and the cam 166 has a scalloped edge 170 engaging the ridged cam follower 168 to provide multiple detents for the knob 120. 
     As the knob 120 is rotated, the cam 166 vertically moves the sleeve 162 which changes the compression on the spring 160. The compression on the spring 160 determines the amount of downward force which must be overcome by the vertical movement of the diaphragm 146 to operate the switch 118. As the downward pressure on the spring 160 is increased by rotation of the knob 120, greater pressures are required at the output of the pump 112 to operate the switch 118. 
     A second cam 172 is also provided on the knob shaft 164 which directly engages the valve frame 156 at a portion 174. As the knob 120 is turned to an off position shown in FIG. 7, the cam 172 engages the portion 174 and causes the valve frame 156 to move vertically and thereby operate a switch lever 176 on the micro-switch 118 to turn the motor 114 off. The second cam 172 moves the valve frame 156 irrespective of the compression on the spring 160. When the knob 120 is turned to other than the off position, the second cam 172 is free of the frame 156 so that the frame 156 is able to move under the influence of the diaphragm 146. 
     Also in a preferred embodiment, a portion of the valve frame 156 which contacts the switch lever 176 is vertically adjustable to compensate for tolerance variations in the various parts which make up the valve control. Vertical adjustment is provided by a spiral cam 178 mounted for rotation at an axis 180 on the valve frame 156. A spiral surface 182 of gradually increasing radius provides contact with the switch lever 176 of the micro-switch 118 so that, as the spiral cam 178 is rotated, more or less vertical movement of the valve frame 156 is required to operate the switch 118. 
     A regular row of teeth 184 is provided in a semicircular arrangement on the spiral cam 178. The teeth are engaged by a pin 186 extending from the valve frame 156, the cooperative engagement between the pin 186 and the teeth 184 enabling the spiral cam 178 to be set at a desired location and thereafter remain until further adjustment is required. 
     The valve control knob 120, thus, provides a dual function in that it operates the switch 118 to turn on and off the motor 114 which drives the pump 112, and the knob 120 also controls the pressure at which an automatic shut-off of the pump 112 occurs. 
     Referring now to FIG. 8, the power base 112 is shown with the top 22 in the open position. A paint can PC rests on the receiving surface 126 of the lower portion 18 and may be easily removed therefrom while the top 22 is up. The intake tube 30 is provided at a location in the top 22 such that it is out of the paint in the paint can PC when the top 22 is in the open position, yet does not encounter the edge of the paint can PC during lifting and lowering of the top 22 and still reaches near the bottom of the can PC for pumping virtually all the paint therefrom. 
     The full length of the lift handle/rest 44 pivots when the top 22 is moved about the hinge 90 so that the applicator handle 14 can remain resting in the lift handle/rest 44 during movement of the top 22, such as for changing of paint cans PC. The user&#39;s hand would generally hold the applicator handle 14 in the rest 44 as the top 22 is being lifted, although the trigger 56 of the applicator handle 14 resting in the opening 48 of the rest 44 as well as the flange 50 engaging the constricted portion 88 of the handle 14 at least help retain the handle 14 in the rest 44. The lock 92 is shown in FIG. 8 in the unlock position with the arcuate engaging portion 98 turned to release the depending tang 100 of the top 22. 
     Thus, there has been shown and described a powered paint applicator unit for receiving a standard size paint can PC for drawing paint therefrom through the intake tube 30 by the suction generated by the pump 112. The motor 114 which drives the pump 112 is turned on and off by the knob 120, which also is rotated to regulate the pressure of the paint at which the pump 112 is shut-off. 
     The top 22 of the unit is pivotable upwardly for easy insertion of a full paint can PC in the present unit 10 and for subsequent removal of the paint can PC. When the top 22 is in the closed position, a lock 92 securely holds the top 22 against the paint can PC to prevent spillage and to enable the paint applicator unit 10 and paint can PC to be lifted by the lift handle 44. The lift handle 44 also functions as a rest for the applicator handle 14, the applicator handle 14 preferably including a pinch type flow control valve as disclosed herein. 
     Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventor to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of his contribution to the art.