Automatic seat lifting device for water closets

A toilet seat is provided with a device for lifting it automatically whenever the toilet cover is lifted, and for leaving both seat and cover in place on the bowl after the cover has been lowered. For this purpose the seat is fastened to the bowl by two long screw-threaded bolts which extend below the rear ledge of the bowl and whereof one bolt is longitudinally perforated for insertion of a flexible cable. A tubular guide is adjustably and concentrically screwed onto the bolt end and contains a helical spring. The cable extends through the spring and its lower end is connected to the bottom end of the spring by a plug which can move inside the tubular guide, while its upper end is wound around the hub of the toilet seat. The spring is tensioned by adjusting the position of the tubular guide along the screw-threaded bolt, so as to exert a force on the plug and through the cable on the hub of the seat of a magnitude sufficient to raise the seat alone, but not both the seat and the toilet cover.

BACKGROUND OF THE INVENTION 
The invention relates to water closets, more especially to a device for 
automatic lifting a toilet seat off the bowl of a water closet after use, 
and for keeping it on the bowl, while the toilet cover is closed and 
lowered onto the seat. 
In public lavatories or restrooms, but also in lavatories in airports, 
concert halls, restaurants, hotels, assembly halls, and other public 
places, the toilet seats are frequently soiled and made unsuitable for 
subsequent users by people urinating into the bowl without lifting the 
seat. It also happens that the seat is covered with faeces after use, by 
toilet paper which was intended to be dropped into the bowl, but 
accidentally hits the seat. With primitive people it also happens that 
they step onto the seat proper while using the toilet, which not only 
soils but often damages it. In addition, automatic lifting the seat off 
ther bowl would be beneficial in houses with many children, especially 
boys. 
Therefore, it has long been found necessary to provide a device which will 
automatically lift the toilet seat off the bowl rim as soom as the 
previous user has got up until it is lowered by the next user for sitting 
on it. The known devices mostly consist of a spriral spring wound about 
the axle of the seat, which is tensioned when the seat is on the bowl and 
uncoils, thereby forcing the seat up into more or less vertical position. 
The spring should be just strong enough to lift the seat off the bowl 
while the cover is lifted, but not so strong that it will lift it when it 
is covered by the lowered toilet cover. 
These devices have two inherent drawbacks: 1. they are not adjustable after 
their first fitting in the water closet installation, and in all cases 
where the spring force decreases, they will stop operating. 2. Since the 
spring is to be strong enough to lift the seat from its horizontal 
position, while the lifting moment is the greatest, it accelerates the 
seat and throws it up rather vehemently, causing it to bang against the 
cover and to make unpleasant noise. It is true that the spring force 
decreases while it somewhat uncoils, but it is the inertia of the mass 
which continues driving the seat about its axle, assisted by the spring 
force. 
For these reasons it is the object of the present invention to provide a 
seat-lifting device of the above kind which is fully adjustable from the 
beginning to adapt its lifting force to any weight of both the seat and 
the cover, and which is subsequently adjustable for compensating for 
changes in the spring force, increased friction in the bearings or other 
causes. 
The invention has as its other object to make the device adjustable by any 
housewife or other unskilled person without the use of special tools. 
It is another object to prevent acceleration of the seat movement about its 
axle and thereby preventing its loud banging against the toilet cover. 
It is a still another object to provide a device having a clean and smooth 
surface lending itself to ready cleaning and wiping. 
And it is a final object to provide such device at low cost so as to enable 
any public lavatory and even every household to install a seat-lifting 
device to every water closet in the place. 
SUMMARY OF THE INVENTION 
A toilet seat is generally pivotally movable about horizontal axles which 
are fastened to the rear of the toilet bowl by vertical bolts extending 
through holes in a ledge extending from the bowl to the rear and held in 
position by nuts tightened against the underside of the ledge. The seat 
includes, for this purpose, two hubs at its rear end which are rotatably 
mounted on these axles. In most cases the seat is covered by an oval cover 
which is likewise pivotally mounted on the same axles. With a view not to 
carrying out extensive modifications to the bowl and the seat, the present 
device is designed to utilize the existing fastening means as far as 
possible: the device, therefore, consists essentially of a pliable cord, 
fastened at its one end to, and wound around, the hub of the seat and 
extending through a bore in the vertical bolt underneath the ledge of the 
bowl, where its bottom end is fastened to a bobbin freely movable in a 
tubular guide. The guide has an open bottom end and a solid top which is 
perforated by internal screw thread corresponding to the screw thread of 
the vertical bolt, serving to fasten the guide to the bolt in variable 
longitudinal alignment. A helical spring is positioned inside the tubular 
guide between the solid top and the bobbin in compressed, pretensioned 
state, the tension being defined by a moment that will be sufficient to 
raise the seat off the bowl, whenever the cover is open, while it will be 
insufficient to raise the seat together with the cover. Adjustment of the 
spring tension is carried out by rotating the tubular guide so as to raise 
or to lower it along the vertical bolt, thereby changing the length of the 
compressed spring. Although one device fastened to one side of the seat 
may be sufficient to lift the seat off the bowl, two devices, one on each 
side of the seat, may be provided, thereby permitting the use of weaker 
springs. 
In order to prevent sudden jerking of the seat into open position, the 
bobbin is preferably shaped to form a piston adapted to be moved up and 
down in the smooth, cylindrical bore of the tubular guide, which is closed 
at its bottom end to form a closed cylinder, except for a small orifice in 
its bottom. The downward movement of the piston will create a light 
overpressure in the bottom space of the cylinder-tubular guide and thereby 
slow down the motion of the spring and prevent jerking up of the seat. In 
addition, the piston may be provided with a central bore effecting 
communication between the upper and lower cylinder space which is normally 
closed by a valve which opens and permits air to flow through the bore and 
thereby equalize the pressure, whenever the seat is too vehemently pushed 
down, with a view to preventing damage to the mechanism. 
With the object of facilitating insertion of the cord, the vertical bolt 
and the plug are preferably slotted lengthwise to the width of the cord, 
permitting its sideways introduction through these slots. 
In a simplified embodiment of the invention the tubular guide may be 
omitted altogether and replaced by a nut-shaped spring-support movable 
along the screwthread of the vertical bolt, whereby the helical spring is 
tensioned between this support and the plug at the end of the cord.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring now to FIG. 1 of the drawings, a toilet bowl I contains a 
horizontal ledge 10 at its upper rear end which is perforated by (usually) 
two vertical holes 11. A toilet seat II and a cover III are shown to be 
positioned on the upper surface of the bowl, the cover on top of the seat. 
The seat includes a cylindrical hub 21 on each side, each being pivotally 
fastened to a horizontal axle 22, which is held by a bracket 23, while the 
latter is provided with a horizontal groove 24. The bottom of the groove 
is open towards the ledge surface in the form of a slot 25, serving to 
connect the bracket--on each side of the toilet--to the ledge 10 of the 
bowl. This connection is made by means of a hammerhead-bolt 2 which 
engages the channel by means of its head and is tightened onto the ledge 
by means of a nut 3 on its underside. As can be seen from the drawing, the 
bolt 2 is slotted lengthwise (43) for the purpose of facilitating 
insertion of a cord or cable 4 into its center. Two clamps 40 and 41 are 
fastened to the ends of the cord or cable, the upper clamp 40 serving to 
attach the cable to the seat II, which surrounds the hub 21 about an angle 
of about 200.degree., while the second clamp 41 engages the bottom end of 
a bore in a plug or bobbin 5 which is slotted, similar to the bolt 2, by a 
slot 50. The plug or bobbin 5 is movable in the smooth bore 60 of a 
tubular guide 6, the latter including a solid top 61 and an open bottom 
end. The top is axially perforated by a screw-threaded bore 62 permitting 
its being rotated and shifted along the bolt 2 in upward or downward 
direction. A helical spring 8 is positioned inside the guide between its 
solid top and the plug or bobbin 5 in compressed state, urging the plug 
and the attached cord or cable 4 in downward direction, as indicated by 
arrow F. 
The spring 8 is compressed to a tension so as to exert the exact moment on 
the hub 21 and the seat which will lift the seat alone off the bowl, but 
not together with the cover. This tensioning is carried out by rotating 
the guide about the bolt thread in upward or downward direction, upward 
movement lengthening the spring and reducing the tension, and vice versa. 
In this way the seat will always be in raised state as long as the cover 
is up, and will stay closed together with the cover, after this has been 
lowered. Of course, it may be possible to provide the seat-lifting device 
to a water closet provided with a seat without a cover, and in this case 
the calibration need not be as exact as in the first case. 
The embodiment of a seat-lifting device illustrated in FIG. 2 is in most of 
its parts identical with that shown in FIG. 1, and identical components 
are designated by identical numerals in both drawings. The main difference 
between the two embodiments is the addition of a motion-damping mechanism 
intended to prevent the seat from jerking up and from striking the cover 
too hard and noisily. The introduction of this damping mechanism requires 
some changes to the shape of the tubular guide and the bobbin, as follows: 
The tubular guide 16 serves as a cylinder for the bobbin which acts as a 
piston in the cylinder by the addition of an O-ring 106. The piston is 
upwardly extended to form a bar-shaped spring-guide 116 the upper end of 
which is attached to the end of the cord 4 by means of a loop. The tubular 
guide or cylinder 16 is closed at its upper end by a plug 14 which is 
provided with axial internal screw-thread corresponding to that of the 
bolt 2 and permitting up and down movement of the guide cylinder along the 
bolt. It bottom end is likewise closed except for a small hole or orifice 
17. The spring 8 is positioned in the space between the plug 14 and the 
piston 15 urging the latter in downward direction and tensioning the cord 
4. As soon as the cover III is lifted or a person gets up from the seat, 
the spring 8 expands and pushes the piston 15 and the cord 4 downward, 
thus rotating the hub 21 about its axle 22 and lifting the seat off the 
bowl I. However, in contradistinction to the action of the device of FIG. 
1, there exists a slowing-down of the movement owing to the braking effect 
of the piston inside the guide cylinder which creates a light overpressure 
in the lower cylinder space 9, since air escapes the space through the 
bore 17 at a slowe rate only, thereby slowing dowm the motion of the 
piston and of the seat itself. 
However, there is provided a safety device in the piston serving to prevent 
damage to the mechanism by sudden lowering of the seat from its raised 
position, which would create a slight vacuum in the lower cylinder space 
9. This device includes a small central bore 18 in the bottom portion of 
the piston which connects the upper cylinder space with the lower cylinder 
space and is normally closed by a valve disc 19 urged onto it by a weak 
spring 20. Now, when the seat is pressed down and the piston is pulled up 
inside the cylinder 16, the vacuum in the space 9 pulls the valve disc 19 
off its seat against the force of the spring 20, permitting air to flow 
from the upper into the lower space, thus obviating any resistance to the 
piston motion. The hole 17 in the bottom of the guide cylinder permits 
atmospheric air to enter the space and to equalize any pressure 
differences. 
As mentioned in the introduction, another embodiment may be designed 
wherein the tubular guide is omitted altogether and the spring is placed 
into the space between a screw-threaded plug similar to that designated 14 
in FIG. 2 and a bobbin 5 like that shown in FIG. 1. Adjustment of the 
spring tension is carried out by rotating the plug 14 on and along the 
bolt 2, with the same effect as that attained by the device illustrated in 
FIG. 1. The only drawback of this embodiment would be the exposure of the 
spring to dirt and a less smooth exterior of the entire device. 
It will be understood that the devices shown in the drawings represent only 
two examples of the possible embodiments of the invention, and that 
various alterations and modifications may be carried out to it by a person 
skilled in the art, within the scope of the appended claims.