High-pressure cleaning apparatus with a wobble plate piston pump

• US 5,038,673 A
• Filed: 07/24/1989
• Issued: 08/13/1991
• Est. Priority Date: 01/28/1987
• Status: Expired due to Fees

• Current Assignee: Alfred Kaercher GmbH & Company KG
• Original Assignee: Alfred Kaercher GmbH & Company KG
• Inventors: Schulze, Werner
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): Verdier, Christopher M.
• Application Number:
  US07/391,501
• Time in Patent Office: 750 Days
• Field of Search: 92/71, 92/73, 92/255, 92/172, 92/248, 92/260, 92/241, 92/254, 91/499, 91/500, 91/502, 91/504, 91/505
• US Class Current: 92/71
• CPC Class Codes: F04B 1/124 Pistons
• CPC Class Codes: F04B 1/126 Piston shoe retaining means
• CPC Class Codes: F05C 2201/0478 Bronze (Cu/Sn alloy)

Abstract

In order to produce a high-pressure cleaning apparatus with a wobble plate piston pump which is of less expensive and more wear-resistant design, it is proposed that the piston be made of ceramic and carry a metallic contact element in the region where it contacts the wobble plate.

Claims

1. A wobble plate piston pump comprising:

a wobble plate;

a plurality of unitary ceramic pistons, each having an end extending from a pump chamber and contacting the wobble plate via a metallic contact element in the form of a cap that fits over said end;

wherein said piston includes a circumferential groove for use in mounting the cap to said end with a holding element that engages said groove; and

a clamping ring for maintaining the engagement of said holding element with said groove.

2. A pump in accordance with claim 1 wherein said cap includes a central spacer element that is supported on a front face of said end to space the cap away from said front face.

3. A pump in accordance with claim 1 wherein said cap is secured against rotation by positive engagement with said piston.

4. A pump in accordance with claim 1 wherein said holding element is integral with said cap.

5. A pump in accordance with claim 1 wherein said holding element includes at least one slot in a wall portion thereof for facilitating the pulling of said wall portion into said groove under a clamping force exerted by said clamping ring.

6. A pump in accordance with claim 1 wherein said clamping ring is a shrunk-on metal ring.

7. A pump in accordance with claim 1 wherein said holding element has a detent projection for snapping into said groove when pushed onto said piston end.

8. A pump in accordance with claim 1 wherein said holding element is shrunk onto said piston end for engagement with said groove.

9. A pump in accordance with claim 1 further comprising a spring for pressing said piston against the wobble plate, wherein said holding element includes a support for said spring.

10. A pump in accordance with claim 9 wherein said support has a detent projection for snapping into said groove when pushed onto said piston end.

11. A pump in accordance with claim 10 wherein said holding element and support are of one-piece design.

12. A pump in accordance with claim 9 wherein said holding element and support are of one-piece design.

13. A wobble plate piston pump comprising:

a wobble plate;

a plurality of unitary ceramic pistons, each having an end extending from a pump chamber and contacting the wobble plate via a metallic contact element in the form of a cap that fits over said end;

wherein said piston includes a circumferential groove for use in mounting the cap to said end with a holding element that engages said groove; and

a spring for pressing said piston against the wobble plate, wherein said cap further comprises a radially protruding flange facing away from a front face of said end to support said spring.

14. A pump in accordance with claim 13 wherein said holding element is integral with said cap.

15. A wobble plate piston pump comprising:

a wobble plate;

a plurality of unitary ceramic pistons, each having an end extending from a pump chamber and contacting the wobble plate via a metallic contact element in the form of a cap that fits over said end; and

a reinforcement inlay embedded in said ceramic piston;

wherein said reinforcement inlay comprises steel filaments extending parallel to one another.

16. A wobble plate piston pump comprising:

a wobble plate;

a plurality of unitary ceramic pistons, each having an end extending from a pump chamber and contacting the wobble plate via a metallic contact element in the form of a cap that fits over said end; and

a reinforcement inlay embedded in said ceramic piston;

wherein said reinforcement inlay comprises glass fibers extending parallel to one another.

17. A wobble plate piston pump comprising:

a wobble plate;

a plurality of unitary ceramic pistons, each having an end extending from a pump chamber and contacting the wobble plate via a metallic contact element;

wherein said metallic contact element is a disc having at least one projection extending into a complementary recess in a front face of said piston end.

18. A pump in accordance with claim 17 wherein said disc is secured against rotation by positive engagement with said piston.

19. A pump in accordance with claim 17 wherein said disc includes a central shaft for penetrating a central blind hole in said piston end.