Animal husbandry – Waste toilet or related device – Walled receptacle; e.g. – litter box – etc. – containing...
Reexamination Certificate
2002-02-05
2003-05-13
Poon, Peter M. (Department: 3643)
Animal husbandry
Waste toilet or related device
Walled receptacle; e.g., litter box, etc., containing...
C119S163000, C119S161000
Reexamination Certificate
active
06561131
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a pet toilet for collecting and disposing of animal waste products. More particularly, the invention relates to a pet toilet for dealing with pet waste after the pet has used a litter chamber.
2. Description of Related Art
Given the natural behavior of house cats when it comes to their elimination habits, cat owners have continuously sought a device which cats would use which would at the same time require little cleaning, be of low cost, and be environmentally sound. The prior art solutions began with plain tubs holding shredded newspaper, sand or sawdust. This created a soggy mess which needed to be emptied often. Although they were low cost and relatively easy to clean, these devices presented odor and sanitation problems for both the cat and its owner. From that low-tech beginning, the art has gone through several major evolutions.
First, there were generations of litters. Aromatic saw dust, wood chips such as cedar or pine, and pelletized paper with scent added all have been marketed throughout the years. These litters turn out not to be much different than what one could make at home on their own. The chief action of these litters is to absorb liquid, and, to an insignificant degree, odor.
Pelletized clay litters came next. These litters afforded somewhat better liquid and odor absorption, allowing them to be used for a slightly longer time period before the entire contents of the litter needed to be changed. Due to the longer time period between changing the litter, however, the odor actually was worse due to the rapid conversion of cat urine into ammonia.
A major advancement came with the advent of litters which “clump” in the presence of urine due to the addition of bismuth or other materials in the litter. These litters had the advantage of containing an animal's liquid waste in a compact package for its selective removal from the bulk of the uncontaminated litter. One merely has to rake out the litter box periodically with the use of a small slotted shovel, removing waste and the source of odor. Disadvantages with these types of litters include cost and the fact that these litters are heavy to transport. These type of litters represent only a small gain in time until they are fouled to the point of needing to replace the entire pan. Most significantly, after disposable diapers, these types of litters are the second most damaging pollutants affecting landfills today. Despite these negatives, these clumping litters have gained wide acceptance due to their odor control abilities.
This has fostered the design of several systems of automatic and semiautomatic screening types of litter box systems which afford an attention-free screening out of waste, both urine and solid. While this represents an apparent advantage to the user by saving the time consumed by scooping, the advantage is actually minor. Nothing is gained in terms of cost of the litter, carrying the litter, or the amount of litter ending up in landfills. It seems clear as well that any time saved in not having to manually screen the box is offset when it comes to periodic cleaning of the entire device. This is no doubt necessary and difficult given the need to completely empty the device and clean it using solvents, water and brushes.
Most recently, litter boxes have been designed which use some type of permanent litter, employing mechanical action, or mechanical action and water, to clean the litter after it has been soiled. One such mechanical device is described in U.S. Pat. No. 4,854,267. This device places non-absorbent granular litter on a screen which is over a container meant to contain the liquid waste after it drains through the granular litter. Solid waste remains in the granular litter for the cat to bury. When the cat owner desires to clean this device, a hand-operated lever activates a system of levers, which flip the litter container into a vertical position. This action sifts out the solid waste, projecting it into a container, and propels the collected liquid waste into the same container for disposal. The drawbacks of the device are extreme. The propensity for odor generation is greatly enhanced due to the fact that the liquid waste has no contact with any absorptive material, as well as it coming into contact with the solid waste, giving it a further opportunity to disperse. Since there is no provision for cleaning the granular litter incorporated into the device, regular maintenance of the device is impractical.
Another device is disclosed in U.S. Pat. No. 4,593,645. This device utilizes a non-absorbent granular litter, placing it in a two-chambered tub separated by a flap valve. When the time arrives for cleaning out the accumulated liquid and solid waste, no automatic action is employed. The owner uses a spray hose to agitate the litter and break the solid waste free from the litter. At the same time, the litter holding tub is filled with water, thereby floating the solid waste. After accomplishing this, the operator then opens a flap valve of a design to allow the accumulated water, liquid and floating solid waste to be carried out into the second chamber quickly, to carry out all the floating solid waste. While this design is simple enough to be inexpensive, the litter is not cleaned effectively enough to assure no odor build up. It is also apparent that the litter remains quite wet, a strong deterrent to a cat's continued use.
Another cat box employing mechanical action and a water bath to float solid waste off of a nonporous litter is described in U.S. Pat. No. 5,791,288. In this device, a special litter is manufactured which is the only litter that can be used with the device. This litter is composed of soft iron pellets with a plastic hull or hollow iron pellets. The desired effect of using these pellets is that they will float in water. Since they are a magnetic material, however, they will respond to electromagnetic force by being pulled downward when in a water bath. These electromagnets are movable as well. The operation of this box is such that, when cleaning is desired, water fills the tub containing these pellets. The electromagnets are put into motion so as to break up solid waste as well as free the solid waste from its attachment to any of the pellets. After a predetermined time for this cycle, more water is added to the tub. This creates a condition whereby solid waste is floated up to a drain-off tube where the waste particles can be drained off with water. The effectiveness of this portion of the device's operation is enhanced by the ability of the electromagnets to pull the pellets down and alternately to free them to rise in the water. By repeating this action, it is expected that complete cleaning of the pellets and the box will be accomplished. After draining off the remainder of the water, the electromagnets can be further activated to agitate the pellets to quicken their drying.
While the simplicity of design of the '288 litter box leads to low cost construction and assured reliability, it seems that there will be high costs involved with several aspects of its manufacture and its continued use. The pellets, being of special design, will be costly as well as difficult to manufacture. Their weight to buoyancy ratio, as well as their degree of response to the applied electromagnetic force needs to be precise. The method of cleaning requires a large amount of water for proper operation. A large amount of copper is needed to develop the required electromagnetic force. A large amount of electrical power is consumed during use.
The Litter Maids® self-cleaning cat litter box, manufactured by Applica Consumer Products, Inc, of Miami Lakes, Fla., uses conventional clumping cat litter. When a photocell arrangement detects the presence of a cat in the litter box, a timer is started, and ten minutes later a rake travels the length of the box, raking the clumped litter into a storage container. This product is only a small improvement over the conventional litter box, with all
Brown & Michaels PC
Olszewski Joan M.
Poon Peter M.
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