Abstract:
A device for collecting excrements of pet animals, more particularly a so-called litter box for cats, of the type which at least consists of a receptacle ( 2 ) in which a filling material ( 3 ) can be provided, a carrying element ( 4 ) which can be moved through the receptacle ( 2 ) in order to remove waste substances ( 5-6 ) from the filling material, and wherein the device ( 1 ) is equipped with a removal unit ( 29 ) which cooperates with the carrying element ( 4 ) and removes waste substances ( 6 ) from the carrying element ( 4 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a device for collecting excrements of pet animals, more particularly a so-called litter box for cats, as well as to an auxiliary element which can be applied therewith. 
     2. Related Art 
     It is known that such devices substantially consist of a receptacle in which a filling material can be provided. It is also known that hereby a filling material, such as grains of an absorbing material, for example, based on bentonite, can be applied which, when coming into contact with a liquid, such as the urine of the animal, clumps to a larger substance. 
     In such a receptacle, waste substances are found, on one hand, in the form of solid or semi-solid excrements and, on the other hand, in the form of substances which, as aforementioned, have been formed as a consequence of the fact that a certain quantity of the filling material has come into contact with the liquid excrements, more particularly, the urine, of the animal. 
     It is known that such devices can be equipped with a carrying element which can be moved through the receptacle in order to automatically remove the aforementioned waste substances from the filling material. An example of such a device is commercialized, amongst others, by the Windmere company, and is traded under the trade name of LitterMaid. Hereby, the carrying element consists of a comb which is moved through the filling material like a rake. This comb has teeth which are situated at mutual distances which are larger than the diameter of the grains, in such a manner that the comb can move freely through the grains, whereas larger waste substances are carried off with the comb to an extremity of the receptacle, where a receiving container is situated. 
     The present invention aims at an improved device for collecting the excrements of pet animals, more particularly an improved device of the aforementioned automatic type. 
     SUMMARY OF THE INVENTION 
     To this aim, the invention relates to a device for collecting the excrements of pet animals, more particularly a so-called litter box for cats, of the type which at least consists of a receptacle in which a filling material can be provided, and a carrying element which can be moved through the receptacle in order to remove waste from the filling material, with the characteristic that the invention is equipped with removal means which can cooperate with the carrying element and remove waste substances from the carrying element. 
     By equipping the device according to the invention with such removal means, it is obtained that waste substances which possibly adhere to the carrying element and do not drop thereof by themselves, for example, because they stick to the carrying element or, in the case of a carrying element in the form of a comb, are stuck between the teeth thereof, are removed explicitely. Hereby, it is excluded that the waste substances, during the backward movement of the carrying element, end up in the receptacle again or permanently, remain at the carrying element and have to be removed manually. 
     Preferably, the removal means are designed as loosening means, more particularly, in the form of a scraper, with which waste substances which have adhered to the carrying element are removed from this carrying element. 
     In the case that the carrying element consists of a comb which is movable through the receptacle, the removal means preferably consist of elements which can be moved in the interspaces between the teeth of the comb and thereby push loose the waste and other substances situated in between them, more particularly, adhered to and/or stuck in between them. In the most preferred form of embodiment, these elements in their turn are also formed by the teeth of a comb. 
     In the most preferred form of embodiment, the aforementioned elements are rotatable, whereby they are rotated during their activation through the interspaces between the teeth of the carrying element. This is preferably performed in such a manner that they, during the pushing off, pass alongside the teeth of the carrying element in such a manner that they perform a movement towards the free extremities of the teeth as well as from the back to the front. As a consequence of this movement, substances stuck in between the teeth of the carrying element are pushed off therefrom in an optimum manner. 
     In the most preferred form of embodiment, the device comprises automatic operation means for activating the removal means at least each time when the carrying element is active. As a result thereof, it is guaranteed after each cleaning cycle that no substances remain at the carrying element. 
     Preferably, the carrying element as well as the removal means, more particularly the loosening comb, will be mounted on one and the same movable carriage. In such a case, it is also preferred that the removal means, more particularly loosening means, are situated such that they are activated directly or indirectly by the movement of the carriage, in such a manner that no separate drives, such as a special drive motor or similar, will have to be provided. 
     In a practical form of embodiment, use is made of an operation element which, when the carriage has come into a certain position, cooperates with a stop-forming part, whereby the removal means, more particularly the aforementioned loosening comb, are activated by the contact of the operation element with the stop-forming part. 
     Furthermore, the device, as known, preferably shall be equipped with a receiving container for the removed waste substances. In such a case, the removal means preferably are provided with operation means which are designed in such a manner that the removal means are activated at that moment when the carrying element is situated at the height of the receiving container. Hereby, it is obtained that not only the waste substances pushed off freely by the carrying element ahead thereof end up in the receiving container but also the waste substances which are loosened from the carrying element by the removal means. 
     According to a particular form of embodiment, the removal means are situated at the height of one of the extremities of the device and are installed in such a manner that they cooperate with the carrying element when this latter reaches the extremity concerned. The loosening movement then is obtained by the mutual movement between the moving carrying element and the removal means situated fixedly at one extremity of the receptacle. 
     Besides, the device preferably also comprises operation means which allow that the removal means, more particularly loosening means, at least can be controlled manually. In the case of a non-automatically operating device, the carrying element then can easily be freed of substances adhered thereto by operating the removal means manually now and then. In the case of a device which does work automatically, such manual operation means allow for an additional manual control of the removal means, if desired. 
     The invention also relates to an auxiliary element which can be mounted on an existing device for collecting excrements of pet animals, in order to transform it into a device according to the present invention. To this aim, this auxiliary element consists of a loosening element which can cooperate with the carrying element of such device and which is provided with mounting means, such as fixation flanges for installing it on the existing device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     With the intention of better showing the characteristics of the invention, hereafter, as examples without any limitative character, several preferred forms of embodiment are described, with reference to the accompanying drawings, wherein: 
     FIG. 1 in perspective represents a view according to the invention; 
     FIG. 2 represents a cross-section according to line II—II in FIG. 1, for another position; 
     FIGS. 3 and 4 at a larger scale represent the portion indicated by F 3  in FIG. 2, for another two different positions; 
     FIG. 5 at a larger scale represents a view according to arrow F 5  in FIG. 1; 
     FIGS. 6 and 7 schematically represent a portion of a variant, for two different positions; 
     FIG. 8 represents a portion of another variant of the invention; 
     FIG. 9 represents a cross-section according to line IX—IX in FIG.  8 . 
    
    
     DETAILED DESCRIPTION 
     As represented in the FIGS. 1 to  4 , the device  1  consists of a receptacle  2  in which a filling material  3  is provided, and a carrying element  4  which can be moved through the receptacle  2  in order to remove waste substances  5 - 6  therefrom. 
     The carrying element  4  substantially consists of a comb  7 , extending over the width of the receptacle  2 , with downward-directed teeth  8  and is fixed at a carriage or sledge  9  which can move to and fro alongside guidings  10  in the side walls  11  of the receptacle  2 . 
     The guidings  10  have such a form that the comb  7  can move from a rest position A to a lowered position, whereby the comb  7  is drawn through the filling material  3  like a rake and subsequently is brought upward up to over the edge  12  of the receptacle  2 , from the position C to the position D, respectively. 
     The drive of the carriage  9  is performed by means of a motor and gear wheels  14  driven thereby which engage in toothings  15  at the height of the guidings  10 . The motor  13  is actuated by means of a control and supply unit  16  which is supplied by means of a battery  17  or a connection to the mains which is not represented. The electric coupling between the motor  13  and the control and supply unit  16  is performed, for example, by means of a cable  18  winding up automatically. 
     The motor  13  can be switched on automatically or manually. For the automatic switching-on, use is made of an optical sensor  19  which is coupled to the unit  16 , in such a manner that the carriage  9  is moved to and fro automatically each time when a certain period of time has passed after the presence of an animal in the device has been detected. Limit stop switches  20  and  21  thereby control the end of the forward, backward respectively, movement of the carriage  9 . 
     At the extremity  22  of the receptacle  2 , a receiving container  23  is situated which is closed off by means of a cover lid  24 . By means of a clamping coupling  25 , the cover lid  24  is fixed at a swivellable element  26  which is provided with operation arms  27  with guiding edges  28  cooperating with the carriage  9 , in such a manner that the element  26  and the cover lid  24  fixed thereon can be swivelled open by the approaching carriage  9 . 
     The particularity of the present invention consists in that the device  1  is equipped with removal means  29  which can cooperate with the carrying element  4 . 
     In the represented example, these removal means  29  consist of a second comb  30  with teeth  31  which can be moved between the teeth  8  of the first comb  7 . To this aim, in the represented example the comb  30  is fixed at the carriage  9  and can be rotated around the indicated rotation axis  32 . 
     The teeth  31  are bent. The convex sides  33  work as pushing-off side. 
     The removal means, in other words, the comb  30 , are provided with an operation element in the form of a lever arm  34  which can cooperate with a stop-forming part  35 , which in this case is formed by the underside of the aforementioned cover lid  24  and/or element  26 . 
     The removal means, or in this case, thus, the comb  30 , are also provided with reversing means forcing the comb  30  towards the rest position, which means in the represented example consist of one or more torsion springs  36  provided at the height of the rotation axis  32 . 
     At the element  26 , elastic means  37  in the form of springs are provided which force the element  26  downward until the closed position of the cover lid  24  is obtained. 
     The working of the device  1 , and more particularly of the carrying element  4  and the removal means  29  applied according to the invention, can be deduced from the FIGS. 2 to  4 . 
     In rest position, the carrying element  4  is situated in position A of FIG.  2 . After the animal concerned has used the device  1 , which is detected by the optical sensor  19 , the unit  16  provides for that the carriage  9  comes into motion. Hereby, this carriage  9  moves through the receptacle  2 , whereby the teeth  8  of the comb  7  are pushed through the filling material  3 , as indicated by position B in FIG.  2 . Larger parts of waste substance  5  are pushed away in front of the teeth  8 , but it may happen that smaller parts of waste substance  6  become stuck between the teeth  8 . 
     During the further movement, the carriage  9  comes into contact with the edges  28  of the arms  27 , as a result of which the element  26  together with the cover lid  24  fixed thereon is swivelled open. 
     When the carriage  9  has come into the position C of FIG. 3, the waste substance  5  is dropped over the edge  12  into the receiving container  23 . 
     During the further movement of the carriage  9 , the lever  34  comes into contact with the underside of the cover lid  24 , as a result of which this lever  34  is pushed in against the force of the springs  36 , with the consequence that the comb  30 , as indicated by arrow R in FIG. 4, is rotated and stuck parts of waste substance  6  are pushed off from in between the teeth  8  by means of the teeth  31 , as a result of which also these parts of waste substance  6  end up in the receiving container  23 . 
     By means of the placement of the combs  7  and  30  represented in the figures, it is obtained that the teeth  31  during their rotation pass alongside the teeth  8  in such a manner that they perform a movement towards the free extremities of the teeth  8 , as well as from the rear to the front, as a result of which an efficient loosening movement is realized. 
     Because the teeth  31  push with their convex side against the part of waste substance  6 , the contact surface generally is small and the risk is small that this part of waste substance  6  in its turn adheres to the teeth  31 . 
     The springs  37  provide for that a sufficiently large reversing force is exerted upon the element  26  and the cover lid  24  fixed thereon, in order to obtain that the lever  34  is swivelled. 
     The limit stop switch  20  provides for the reversion of the movement of the carriage  9 . 
     During the backward movement of the carriage  9 , the comb  30 , under the influence of the force exerted by the springs  36 , is swivelled back into its initial position and the cover lid  24  swivels back downward, as a result of which the spreading of odor from the receiving container  23  is prevented. 
     Finally, the carriage  9  is stopped again in the rest position A by means of the limit stop switch  21 . 
     In order to empty the receiving container  23 , it can be taken off with closed cover lid  24  in a known manner, by pushing off this cover lid  24  at the height of the clamping coupling  25  from the element  26 , swivelling the element  26  completely upward and lifting the closed receiving container  23  out of the device  1 . 
     It is noted that the comb  30  can be fixed by means of hinges which are attached fixedly at the carriage  9 , with which it is meant that these hinges are attached at the carriage  9  in such a manner that they cannot be dismounted in a simple manner. Preferably, however, as represented in the figures, use is made of an easily dismountable comb  30  which, by means of hinges  38 , is coupled to fixation flanges  39  wich can easily be attached on the carriage  9  by means of screws  40 , or in any other manner, for example, by means of a snap-on connection. 
     Such dismountable construction allows to remove the comb  30  in a simple manner, for example, in order to clean the device  1 , and more particularly the combs  7  and  30 . This dismountable construction also allows to commercialize the comb  30  as a separate accessory which can be mounted on the existing or new devices, if desired. 
     It is clear that different variants are possible. So, for example, do the removal means not necessarily have to be mounted on the carriage  9 . FIGS. 6 and 7, for example, represent a variant wherein the comb  30  is fixed at the underside of the element  26  or another constructional part of the extremity  22  of the device  1 . During the approach of the comb  7 , the teeth  31  engage between the teeth  8 , according to the position from FIG.  6 . During the further movement of the comb  7 , this latter pushes against the comb  30  or a stop  41  cooperating therewith, with as a result that the teeth  31  perform a push-off movement between the teeth  8 , analogous to the movement which is represented in FIG.  4 . 
     Although it is preferred that the removal means, or, thus, the comb  30 , are activated at the moment when the carrying element  4  is situated above the receiving container  23 , this is no strict necessity. 
     In FIGS. 8 and 9, a variant is represented whereby the removal means  29  are attached at that extremity  42  of the receptacle  2  which is situated opposite to the extremity  22 . Hereby, the removal means  29  consist of a series of protrusions  43  on the wall of the receptacle  2  which are situated such that they penetrate between the teeth  8  of the carrying element  4 , at the moment when this latter moves back into the rest position A, this such as indicated in FIG.  9 . Thereby, stuck waste substances  6  are pushed loose but, however, remain in or upon the filling material  3  until a subsequent cleaning cycle is performed by the carrying element  4 . The risk of the waste substances  6  of getting stuck again between the teeth  8 , then, is small. 
     It is noted that the removal means not necessarily have to consist of the teeth of a comb but also other elements can be applied which can penetrate between the teeth  8  of the carrying element  4 . Depending on the construction, it is also so that other removal means than elements penetrating between the teeth  8  can be applied, such as, for example, one or more doctor blades extending over the width which are moved up and down along the front side, rear side respectively, of the teeth  8 . 
     The carrying element  4  also does not necessarily have to be an element which is placed on a carriage  9 . 
     Instead of the aforementioned elastic means  37 , use may also be made of means forming a fixed stop for the element  26 , in such a manner that in FIG. 3, the end position of this element is determined unambiguously. In a practical form of embodiment, this can be realized by replacing the springs  37  by a connection with a fixed maximum length, such as a rope, chain or similar. Use may also be made of a fixed stop which forms part of the side wall  11  of the receptacle or similar which limits the rotation of the element  26  or of the arms  27 . 
     The present invention is in no way limited to the forms of embodiment described as an example and represented in the figures, however, such device and auxiliary element can be realized according to various variants without leaving the scope of the invention.