Plastic sanitary pump

A plastic sanitary pump comprises a cylinder, an elastic disc attached to the bottom of the cylinder, a piston and piston rod, a cap covered on the top of the cylinder and a handle connected with the upper end of the piston rod. All the parts are made of plastic material; therefore, the present invention is light weight and will not rust. It can be operated easily and has excellent effect in releasing the blockage in drain pipe of toilet.

BACKGROUND OF THE INVENTION 
This invention concerns a plastic sanitary pump, particularly a PVC made 
embodiment which has a simple structure and can be operated easily to 
clean and release the blockage in a drain pipe by means of sucking and 
pressing. 
The conventional device only presses the blockage in a drain pipe, but it 
has no the function of suction, so the blockage is often pressed together, 
making the condition worse. A new toilet blockage releasing device has 
been invented (Chinese Pat. Appn. No. 6424220), but it has a complicated 
structure which has a lot of parts and a high cost. Moreover, most of its 
parts are made of metal which rust easily, so its life is short.

DETAILED DESCRIPTION OF THE INVENTION 
This invention relates to a plastic sanitary pump which is made of PVC 
plastics or other suitable plastic material by means of extrusion. Owing 
to the present invention, the pump has a simple structure which can be 
produced easily and cheaply. Further, the present invention has 
effectively functions for releasing a blockage in a drain pipe. Referring 
to the FIGS. 1-3, the present invention comprises the following essential 
parts: (1) a cylinder, (2) a handle, (3) a piston rod (4) a piston, (5) a 
elastic disc or flexible sealing cup (6) a cap. All of the parts are made 
of PVC plastics or suitable plastic material. The piston (4a) and elastic 
disc (5) are elastic. The piston rod (3) is a plastic tube. As shown in 
FIG. 4, the piston (4) is fixed on washer plug (401) first, then the 
washer (402) is set on the piston (4). Adhesives may be used between the 
contact surfaces of these parts to stick them together. After that, the 
washer plug (401) is inserted into one end of the piston rod (3), then the 
joint position is heated to make the end of the piston rod (3) fasten on 
the washer plug (401). The next step is to insert the upper end of the rod 
(3) into the cap (6), then fix the handle (2) on the upper end with 
adhesives and rivet (201). Next, insert the embodiment of piston (4), 
washer plug (401), washer (402), piston rod (3), cap (6) and handle (2), 
into the cylinder (1) downwardly and adhere the plastic disc (5) on the 
lower end of the cylinder (1). Finally, fix the cap (6) on the upper end 
of the cylinder (1) with adhesives, with the handle (2) remaining above 
the cap (6). Thus, the present invention is finished. 
In the above-mentioned structure, the cap (6) is like a bowl which has one 
or more air outlets on its border. The cap and the upper end of the 
cylinder can also be screw-coupled together instead of using adhesives (as 
shown in FIG. 8), and they can be separated for easy cleaning. There is a 
disc (202) under the handle (as shown in FIG. 8), which prevents the 
unfavourable water or air from reaching a user's hand while operating the 
present invention. The elastic disc (5) on the lower end of the cylinder 
(1) has a shape of a disc or bowl, which includes an inner rim (501) 
adjacent to its border on the bottom. The border and the inner rim (501) 
enhance the effect of the air-tight fit during operation. Of course, the 
inner rim can be increased if necessary. As shown in FIG. 6, the piston 
(101) can be made with hard plastics (102) and covered by elastic plastic 
(103), the central plug can be inserted into the piston rod (3) and they 
may be fixed together with adhesives and rivet (104). Alternatively, the 
piston (105) may have the structure shown in FIG. 7, which includes a 
round metal plate (106) in it. The central plug can also be inserted into 
the piston rod (3) and fix them together with adhesives and pin (104) or 
screw-coupling. The FIGS. 9, 10 and 11 show the other structures of the 
lower end of the cylinder (1) and the plastic disc (5). One or more 
flanges on the lower end of the cylinder (1) may be combined with the 
corresponding grooves on the top opening of the elastic disc (5). 
Therefore, the plastic disc (5) may be fixed on or taken off from the end 
of the cylinder (1) easily. When the present invention is used to treat a 
drain pipe having a smaller diameter, the elastic disc (5) having a 
smaller opening on its bottom, as shown in FIG. 9, can be used instead of 
wider one. When operating the present invention, the handle (2) should be 
pressed to the end, then the elastic disc (5) is put on the opening (701) 
of drain pipe (702). The cylinder (1) is held with one hand, and the 
handle (2) is pulled up and pressed down with the other hand. The piston 
(4) moves up and down with the handle (2). Therefore, the blockage (8) in 
the toilet or drain pipe (702) will be sucked and released rapidly. If the 
blockage (8) is not released completely, the present invention may be 
moved away and the above-mentioned process repeated again. The present 
invention can be operated contrary, that is to pull the handle (2) to the 
end, then put the elastic disc (5) on the opening of drain pipe (702). 
When said handle is pressed downward, the piston (4) moves down, which 
presses and releases the blockage (8) in the toilet or drain pipe (702). 
According to our tests, any blockage in a toilet or drain pipe can be 
released and cleaned within five seconds. All the parts of the present 
invention are made of plastic material and the whole embodiment weight is 
only 0.7 kg. Therefore, the present invention is really a sanitary tool of 
easy operation, practicality and high efficiency.