Patent US4168557A successfully refreshed from Google Patents.
US4168557A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pool cleaners
Assignee: Wira Ltd
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Filing: 1977-12-02
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Granted: 1979-09-25
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Expires: 1997-12-02
Abstract
Abstract An electrically driven endless track vehicle draws water through a filter compartment and expels the water normal to the surface on which the vehicle runs. An unbalanced float and random timing of a reversing switch causes the vehicle to traverse a pool floor randomly.
Inventors
- 👤 Wilhelm Rasch, deceased
- 👤 heiress Gertrud Rasch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:32
CPC Classifications
E; E04; E04H; E04H4/00; E04H4/14; E04H4/16; E04H4/1654
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
141 words
A pool cleaner comprising: a body; four wheels on the body mounted on two shafts; endless tracks joining pairs of wheels from opposed shafts; an electrically driven motor for driving the wheels to propel the body along the floor of a pool; a filter chamber in the interior of the body; an inlet to the chamber on the base of the body; an electrically driven pump for drawing water through the chamber; a pump outlet from the body for expelling water in a direction normal to the base of the body; and a float pivoted to the body to extend above the body when the body is submerged in water for tending to keep the body upright in water and the float being unbalanced about the body to cause the body to move down in water at angle to the vertical.
Claim 2
Dependent Claim
141 words
A pool cleaner comprising: a body; four wheels on the body mounted on two shafts; endless tracks joining pairs of wheels from opposed shafts; an electrically driven motor for driving the wheels to propel the body along the floor of a pool; a filter chamber in the interior of the body; an inlet to the chamber on the base of the body; an electrically driven pump for drawing water through the chamber; a pump outlet from the body for expelling water in a direction normal to the base of the body; and a float pivoted to the body to extend above the body when the body is submerged in water for tending to keep the body upright in water and the float being unbalanced about the body to cause the body to move down in water at angle to the vertical.
Claim 3
Dependent Claim
23 words
The cleaner claimed in claim 1 in which the shafts are enclosed by drums each carrying a brush extending between the endless tracks.
Claim 4
Dependent Claim
23 words
The cleaner claimed in claim 2 in which the inlet is closed by a pivoted flap biased to prevent flow from the chamber.
Claim 5
Dependent Claim
23 words
The cleaner claimed in claim 3 in which the filter chamber comprises a screen wall attached to a detachable base to the body.
Claim 6
Dependent Claim
14 words
The cleaner claimed in claim 4 including a filter bag lining the screen wall.
Claim 7
Dependent Claim
23 words
The cleaner claimed in claim 5 in which the bag is lined with a layer of felted material spray painted on each side.
Claim 8
Dependent Claim
15 words
The cleaner claimed in claim 6 in which the pump is an axial flow pump.
Claim 9
Dependent Claim
45 words
The cleaner claimed in claim 7 including a sealed off hollow in the body housing the electrical components and a filter chamber to either side of the hollow and a space above the hollow and the filter chambers from which the axial pump draws water.
Claim 10
Dependent Claim
19 words
The cleaner claimed in claim 8 including a bleed hole from the space to the discharge of the pump.
Claim 11
Dependent Claim
38 words
The pool cleaner claimed in claim 1 in which the motor is reversible and including a reversing switch for the motor and a random signal generator for generating switching impulses to operate the reversing switch at random intervals.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-09-24 | 1983-03-26 | 1983-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-09-24 | 1987-03-26 | 1987-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-09-24 | 1991-03-26 | 1991-09-25 | $7700.00 | Window Closed / Lapsed |