Pumps – Expansible chamber type – Including valve assembly – disassembly – or inspection...
Reexamination Certificate
1999-01-13
2001-10-23
Freay, Charles G. (Department: 3746)
Pumps
Expansible chamber type
Including valve assembly, disassembly, or inspection...
C417S516000, C417S900000
Reexamination Certificate
active
06305916
ABSTRACT:
BACKGROUND
This invention relates to concrete pumps, and, more particularly, to a concrete pump with a pivotable S-valve and hopper assembly.
Concrete pumps are well known in the construction industry and are used for pumping concrete or other pumpable construction materials. Concrete pumps are described, for example, in U.S. Pat. Nos. 3,612,730, 3,897,180, and 4,241,641.
Most concrete pumps which are currently being manufactured include two concrete pumping cylinders and an S-shaped tube valve for alternately connecting the outlet end of each pumping cylinder to the discharge conduit of the concrete pump. The S-tube valve is pivotally mounted in a concrete hopper. As the piston in one of the pumping cylinders moves toward the hopper to pump concrete through the S-tube valve to the discharge conduit, the piston in the other pumping cylinder retracts away from the hopper to draw concrete into the cylinder.
A major problem with the S-tube valve is clean-up. Material builds up and hardens in the bottom or inlet end of the tube, and the hardened material is difficult to remove because of the curved shape of the tube. The problem is particularly acute with small diameter S-tubes.
The curved tube also makes it difficult to service the outlet end of the pumping cylinders. The pumping pistons carry seals which must be changed from time to time.
SUMMARY OF THE INVENTION
The invention pivotally mounts the hopper and S-tube valve assembly on the frame or chassis of the concrete pump so that the hopper and valve can swing away from the outlet ends of the pumping cylinders. The inlet end of the S-tube valve is thereby exposed for easy cleaning. The outlet ends of the pumping cylinders are also exposed to permit the piston seals to be changed. When the S-tube valve and hopper assembly is pivoted to its closed position against the outlet ends of the cylinders, the assembly is quickly and easily locked in place by two bolts. O-rings which surround the cylinders sealingly engage the hopper to prevent the concrete from leaking.
REFERENCES:
patent: 3146721 (1964-09-01), Schwing
patent: 3612730 (1971-10-01), Reinert
patent: 3639086 (1972-02-01), Robbins
patent: 3650641 (1972-03-01), Reinert
patent: 3741078 (1973-06-01), Johnson
patent: 3778193 (1973-12-01), Reinert
patent: 3811802 (1974-05-01), Semple
patent: 3897180 (1975-07-01), Reinert
patent: 4019839 (1977-04-01), Schwing
patent: 4198193 (1980-04-01), Westerlund et al.
patent: 4241641 (1980-12-01), Reinert
patent: 4437817 (1984-03-01), Metzelder
patent: 4502851 (1985-03-01), Calvin et al.
patent: 4533300 (1985-08-01), Westerlund et al.
patent: 4563135 (1986-01-01), Riker
patent: 5061158 (1991-10-01), Egli
Grainger, General Catalog #308; Addison, 1130 Fullerton Ave, 60101; p. 1747, Dec. 1991.*
Schwing Catalog pages published before 1998?.
Reinert Concrete Pumps Catalog published before 1998?.
Reinert Concrete Pumps Parts Drawing for S-Tube Valve Assembly for Model 530 published before 1998?.
Freay Charles G.
Reinert Gerald
Solak Timothy P.
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