Plug for a sink drain

Details Plug for a sink drain Plug for a sink drain

2001-12-07

2002-12-10

Phillips, Charles E. (Department: 3751)

Baths, closets, sinks, and spittoons

Strainer, stopper, plug or closure

Closure

C004S668000

Reexamination Certificate

active

06490739

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plug for a sink drain, and more particularly a drain for a sink drain that is easily manufactured.
2. Description of Related Art
Sinks for various purposes need a plug to keep the water therein until the washing process is completed whereafter the water can be easily drained away by releasing engagement between the sink and the plug. One problem of plugs is that they can be lost or even stolen from a public washroom, and this renders the sink almost useless as no water can be kept in the sink. To overcome such a problem, plugs with a sprung-loaded rod securely extended into a drain pipe of the sink are used, but it is still found that shortcomings exist in the secured plug. For example,
FIGS. 4 and 5
show a prior art plug for a sink drain comprising a hollow body, a connector (
50
), a cap (
60
), and a hollow knob (
70
). The body has a top ingress and a bottom egress. A brace extends across the egress and a screw hole is defined in the brace. The cap (
60
) has tube portion (
62
) and a flanged portion (
64
) extending from a top of the tube (
62
). A bore (
622
) is defined down the tube (
62
), a counter bore (
642
) is defined in the flanged portion (
64
) and a mouth (
644
) is defined at a bottom of the bore (
622
). The counter bore (
642
) has a screw thread (
644
) leading to the bore (
622
). The knob (
70
) has a bottom opening (
72
) leading to a recess (
74
), and a male thread (
76
) formed around a bottom of the knob (
70
) whereby the knob (
70
) can be threadedly engaged with the screw thread (
644
) of the cap (
60
). The connector (
50
) includes a rod (
52
) with a large head (
54
) formed at the top and a screw (
56
) formed at the bottom. The large head (
54
) is sized to be enter the recess (
74
) of the knob (
70
) and the screw (
56
) mates with the screw hole of the body. A cutout (
58
) is formed on a side of the rod (
50
) and includes a partition (
582
) defining two platforms (
584
), and a slit (
586
) defined along a side edge of the platforms (
584
). A spring (
53
) shaped substantially as an inverted T has a top end (
532
) mounted on a top of the partition (
582
), two sides extending down the partition, and two hooks (
534
) moveably received in the slit (
586
) and diametrically protruding from the connector (
50
). A distance across the hooks (
534
) when the spring (
53
) is in a released status is smaller than the diameter of the mouth but greater than the diameter of the bore (
622
). In assembly, the rod (
50
) is inserted in the cap (
60
) via the counter bore (
642
) such that the screw (
56
) protrudes from the mouth (
644
) of the cap (
60
), whereafter the male thread (
76
) of the knob (
70
) is mated with the female thread (
644
) of the counter bore (
642
) of the cap (
60
). Then, the combined connector (
50
), cap (
60
) and knob (
70
) are entered into the hollow body such that the screw (
56
) of the connector (
50
) mates with the screw hole of the brace of the body which is secured to a sink drain. By pulling the knob (
70
) upward, the cap (
60
) is accordingly lifted away from the body until the large head (
54
)of the connector (
50
) abuts a wall defining a bottom of the counter bore (
642
) of the cap (
60
), whereby a gap is defined between the flange (
64
) of the cap (
60
) and the body to allow water to flow into the sink drain. The hooks (
534
) of the spring (
53
) abut a shoulder between the bore (
622
) and mouth (
644
) of the cap (
60
) such that the cap (
60
) can remain in this opened position without need for a user to stand there until all the water has drained away. In a reversal of that process, the knob (
70
) is pushed downward until the flange (
64
) of the cap (
60
) covers the ingress of the body and the hooks (
534
) of the spring (
53
) urge against a wall defining the bore (
622
) of the cap (
60
) whereby the cap (
60
) is held in place to ensure retention of the water in the sink. It is to be noted that one or more gaskets are commonly used but not mentioned here. However, although the prior art plug is very effective in function it is found that the manufacture of the connector is particularly troublesome and expensive. That is, the casting of the connector to include the partition and the slit is too difficult to be commercially viable. The slit must be a very exact size and shape to allow the spring to be received and retained satisfactorily therein, but it is found that inevitable fluctuations in casting result in difficulties for assemblers to fit the spring to the connector. Thus, time is lost in assembly of the prior art plug, as well as excessive costs being incurred through reject quality connectors having to be scrapped. Furthermore, if the spring should become dislodged from the connector it will be flushed down the drain and a complete new plug mechanism will need to be bought and fitted. Even if the dislodged spring still hangs on the connector, refitting the spring is beyond the skill of the lay person and again a new plug mechanism will need to be purchased. Thus, there is a need for a plug for a sink drain with a connector that is effective yet inexpensive and convenient to manufacture and maintain.
Therefore, it is an objective of the invention to provide a plug for sink drain to mitigate and/or obviate the aforementioned problem.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a plug for a sink drain wherein a connector thereof is manufactured easily and at low cost.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.


REFERENCES:
patent: 4720877 (1988-01-01), Watts
patent: 4926507 (1990-05-01), Craig et al.
patent: 5832545 (1998-11-01), Pan
patent: 5881397 (1999-03-01), Hobbs

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