Airless spray pump

Abstract

An airless spray pump is provided with a single-acting piston pump which allows the use of a low-cost yoke drive. Motor and pump shaft are offset for most efficient force utilization.

1. A spray pump powered by a rotary motor having a pinion thereon and comprising:
 a housing; 
 a single-acting piston pump having a pump rod and connected to said housing; 
 a drive gear assembly comprising a gear rotatable about a gear centerline, and an eccentric located on said gear; 
 a bearing located about said eccentric; and 
 a yoke reciprocatingly located in said housing and about said bearing;
 wherein said gear centerline, motor and pinion are offset from the a centerline of said pump to reduce the thrust loads on the yoke and offset and reduce the pump forces. 
 
 
     
     
       2. The spray pump of  claim 1  wherein the teeth on said gear are formed with about a 5° helical angle and about a 25° pressure angle. 
     
     
       3. The spray pump of  claim 1  wherein said motor and pinion are offset from the centerline of said pump to reduce the thrust loads on the yoke and offset and reduce the pump forces is driven by said motor and engages teeth of said gear to rotate said gear and said eccentric about the gear centerline. 
     
     
       4. An airless spray pump having an inlet tube and an inlet filter screen, the improvement comprising said inlet tube being provided with a female threaded end and said inlet filter screen assembly being provided with a male threaded end threaded engagement with female end, said ends having the same size and thread as a common garden hose such that a user need merely remove said screen assembly and attach a garden hose to said inlet tube to flush out the assembly. 
     
     
       5. The spray pump of claim 1, wherein the single-acting piston pump pumps on a downward stroke of the pump rod and loads on an upward stroke of the pump rod. 
     
     
       6. The spray pump of claim 5, wherein the pump rod is aligned with the centerline of the pump. 
     
     
       7. The spray pump of claim 6, wherein the pump rod, yoke, and bearing are located in a common plane. 
     
     
       8. The spray pump of claim 1, wherein the eccentric is integral with a front of the gear assembly. 
     
     
       9. The spray pump of claim 1 and further comprising a motor mounted to a rear portion of the housing. 
     
     
       10. The spray pump of claim 9, wherein the pinion is driven by the motor. 
     
     
       11. A spray pump comprising:
 a rotary motor;   a pinion driven by the rotary motor;   a housing;   a single-acting piston pump having a pump rod and connected to said housing wherein the single-acting piston pump pumps on a downward stroke of the pump rod and loads on an upward stroke of the pump rod, and wherein the pump rod is aligned with a centerline of the piston pump;   a drive gear assembly comprising a gear driven by the pinion about a gear centerline, and an eccentric located on said gear;   a bearing located about said eccentric; and   a yoke reciprocatingly located in said housing and about said bearing so that rotation of the gear and the eccentric produce reciprocal motion of the yoke;
 wherein said gear centerline, motor and pinion are offset from the centerline of said pump to reduce the thrust loads on the yoke and offset and reduce the pump forces. 
   
     
     
       12. The spray pump of claim 11, wherein the pump rod, yoke, and bearing are located in a common plane. 
     
     
       13. The spray pump of claim 11, wherein the pump rod, yoke, eccentric, and bearing are located in a common plane. 
     
     
       14. The spray pump of claim 11, wherein the eccentric is integral with a front of the gear assembly. 
     
     
       15. The spray pump of claim 11 wherein the motor is mounted to a rear portion of the housing. 
     
     
       16. The spray pump of claim 11, wherein the pinion includes teeth that engate teeth on an outer circumferential surface of the gear. 
     
     
       17. The spray pump of claim 11, wherein said teeth on said gear and said pinion are formed with about a 5° helical angle and about a 25° pressure angle.