in the following detailed description , certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 usc 112 , but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims . referring to fig1 and 2 , a toilet bowl 50 with a rim 19 is shown , which typically extends forwardly of the base 28 of the toilet bowl to create an overhang c . this geometry creates an inner floor region x ( shown shaded ) lying beneath the overhang and extending a short distance beyond the overhang , which is stepped on by a standing user facing the toilet ( see foot outlines a ). a seated user &# 39 ; s feet ( see outlines b ), are facing the other way and do not enter that region . this fact is relied on to establish automatic sensing of the user &# 39 ; s needs with respect to whether the toilet seat 1 ( fig3 a ) should be raised or lowered . according to the concept of the present invention , a sensor pad is located at least partially within the floor region x and caused to activate toilet seat raising , which is maintained when foot pressure in region x is detected or applied . the toilet seat 1 is automatically lowered when foot pressure is no longer detected or applied . fig3 a -- 3e illustrate one embodiment of the arrangement used to automatically raise and lower the toilet seat . the arrangement includes the counterbalancing of the toilet seat 1 with respect to its hinging axis , essentially using the hinge 52 as a fulcrum . the counterbalancing may be achieved by mounting a counterweight 8 to the rear of the toilet seat , located on the opposite side of the hinge 52 from the center of gravity of the toilet seat 1 itself . the counterweight 8 is of a heavy material , such as a rod of metal , i . e ., steel or brass , which may be molded or installed in a cavity within the toilet seat 1 . other means of counterbalancing include springs , or springs and weights , etc . the toilet seat 1 rear portion housing the counterweight 8 is angled upwardly from the rim 19 to provide a clearance when the toilet seat 1 is hinged upwardly to be raised . in addition , the hinge standard 54 as well as the pad 7 elevates the toilet seat 1 to also create clearance accommodating the rear counterweighted portion as the toilet seat 1 moves to a raised position . in the fully raised position , the toilet seat 1 is still inclined forwardly somewhat as shown , to allow imbalances about the fulcrum to occur . the toilet seat 1 may have a forward portion of hollow lightweight construction ( which may have internal ribs as described below ) to enable counterbalancing of its entire weight forward of the fulcrum by the counterweight 8 . means are provided for shifting weight supported by the toilet seat 1 with respect to the fulcrum so as to selectively create an imbalance tending to raise or lower the toilet seat . in the embodiment of fig3 a , 3b , means are provided for forcing a liquid out of a cavity 2 located within the toilet seat 1 at the forward end , activated by foot pressure acting on a sensor pad 5 in floor region x . in this embodiment , the sensor pad 5 is used as an actuator to compress air when stepped on , exerting pressure on a resilient bladder 3 and passage 4 in the seat 1 in cavity 2 via an air line 56 , causing the liquid in cavity 2 to be forced out and into a second bladder reservoir 6 in a cavity c within the counterweight 8 via line 58 . this movement of a dense liquid such as glycerine , causes a weight shift to create an imbalance about the fulcrum defined by hinge 52 , such that the seat is caused to be hinged up automatically by the weight of the counterweight 8 and transferred liquid . when the foot pressure is removed , a vacuum may develop causing the bladder 3 to contract , and liquid is drawn back into the cavity 2 gradually establishing an imbalance tending to lower the seat back onto the rim 19 . return of the liquid can be accomplished by providing gas pressure in the cavity c surrounding the bladder reservoir 6 . the flow passages are restricted to produce a reasonable rate of motion of the toilet seat in being raised and lowered to avoid seat impacts . fig3 c and 3d show variations of the arrangement using liquid movement to create the desired imbalances . in the variation of fig3 c , foot pressure on the floor sensor pad 5 causes air pressure inflation of the bladder 3 . liquid is displaced from cavity 2 into a reservoir 6 - 2 which is located externally of the seat . thus , a transfer of weight from the forward side of the fulcrum 12 is accomplished to create the desired imbalance . fig3 d shows a transfer of liquid from the foot pad 5 - 1 the cavity 6 - 3 , and back to the foot pad 5 - 1 . fig3 e shows a variation in which a reversible electric motor 13a drives a pump 82 , which transfers liquid to and from a cavity 6b in the tubular counterweight 8a and a bladder cavity 3a at the forward end of the seat 1a via line 4a . a sensor pad 5a controls energization of the motor 13a to transfer liquid to create the imbalance raising the seat , with a reverse transfer upon removal of foot pressure acting to create the lowering imbalance . fig4 a -- 4c and fig9 show an electromechanical arrangement for alternatively creating an imbalance about the seat fulcrum tending to raise or lower the toilet seat . this includes a small reversible electric motor 13 powered by a battery 14 , both mounted to the rear of the seat 1 ( fig9 ). the motor 13 drives an elongate screw shaft 11 within a tube 10 extending within the seat interior in a front to rear direction . a weighted nut 9 is engaged by the screw shaft 11 so as to travel forwardly and rearwardly with respect to the seat 1 when the motor 13 is activated for driving in either direction . this causes an imbalance tending to raise the seat 1 when the weighted nut is driven to a rearmost position ( shown in phantom ), and to lower the seat when driven to a forward position within the seat 1 . the sensor pad 15 comprises a switch housing 60 causing activation to energize the motor 13 when stepped on , initiating rotation of the screw shaft 11 in a direction moving the weighted nut 9 to the rear position with respect to the fulcrum . instead of wiring , a radio transmitter 16 can send signals to the motor control circuit 62 . when the switch is opened , the circuitry 62 causes the motor 13 to be reversed and drive the weighted nut 9 to its forward position with respect to the fulcrum . the rate of drive of the motor may be set so as to produce a controlled rate of ascent and descent of the toilet seat , avoiding impacting of the seat . fig5 a - 5e show a mechanical actuation means for shifting weight within the toilet seat 1 . fig9 shows that the tube 10 can extend well outside the seat 1 . in this embodiment , a sensor pad 64 comprises an interfit base 27 and cover 30 . a screw shaft 29 is affixed to the cover 30 extends down into a pulley 31 supported by bearing 32 in a base projecting up from the inside of the base 22 . a set of return springs 33 urge the cover 30 and base 27 to be separated . a cable 22 is wound on the pulley 31 and within a guide tube 25 and into a weight guide tube 21 arranged extending front to rear within a cavity in the toilet seat 1 . a series of weights ( such as lead balls ) are attached along the cable 22 within tube 21 . a second cable 18 extends onto a housing 17 for a wind up spring 26 anchored on pin 23 . the cable 18 tends to pull the cable 22 so as to advance the weight 9 forwardly . when foot pressure is applied , the cable 22 is wound onto the pulley 31 , shifting the weights 9 rearwardly , creating an imbalance causing the seat 1 to be raised . when foot pressure is removed , the spring 26 moves the weights 9 forwardly to create an imbalance causing the seat to be lowered . fig6 and 6a show a hinge design which facilities mounting of the toilet seat 1 to standard mounting holes 37 by a special bracket 39 . the special bracket 39 includes a pair of mounting members 34 , each having a hinge piece 40 extending upwardly . this arrangement extends hinge holes 41 acting as the fulcrum point forwardly of the standard mounting holes 37 to allow clearance for the counterweight 8 . a cover 68 is mounted to hinges 42 in conventional fashion . fig7 and 7a illustrate diagrammatically that a shifting weight 70 inside a passage 72 in the toilet seat 1 pivoted on fulcrum 12 can be moved from a forward position to one closer to or over the fulcrum 12 so as to cause varying imbalances with the counterweight 8 ; or , the weight can be shifted to a point to the rear of the fulcrum 12 and over the counterweight 8 by extending the seat 1 and passage 72 . the transfer of weight to either side of the fulcrum 12 reduces the amount of weight which needs to be shifted to create the desired imbalances . a higher clearance over the bowl rim 19 may facilitate accommodating the extra length to the rear of the fulcrum 12 . the special hinge bracket described below alleviates the need for a higher seat . an air gap 36 between the seat 1 and bowl 35 could be provided , as shown , to allow initial adjustments during installation , although this is not preferred . fig8 and 8a show that the passage 70 can be extended to the rear to increase the leverage of the weights 70 and 8 . fig1 a , 10b , and 10c show details of a construction of the toilet seat 1 which allows imbalances to be established without resorting to heavy weights , etc . fig1 a shows a hollow , molded plastic construction of a forward lightweight section 74 of a toilet seat 1a , the rear , heavier section 76 is of a solid construction to contribute to the counterweighting about the fulcrum . a network of radial and circumferential stiffening ribs 40 are molded into the interior of the hollow section 74 for adequate strength . a cover 78 ( fig1 b ) is bonded onto the open bottom of the seat , with a series of pads 80 aligned with rib intersections provided to give adequate support for the hollow section . fig1 c illustrates how the different density portions 74 , 76 and counterweight 8 assist in counterweighting about fulcrum 12 .
an arrangement and method for automatically raising and lowering a toilet seat including a sensor pad located to be stepped on only by a standing user . the toilet seat is counterbalanced , and a shifting of weight causes the seat to pivot up or down . various weight shifting arrangements are described , including an electromechanical drive , a liquid transfer system , and a mechanical drive weight positioner .