Toilet Bowl

The present invention relates to a toilet bowl, to the body of which the pins of the hinges connecting a toilet seat and a toilet lid are formed as spring pins, which are tightly fitted in pin insertion holes and give desired rotational friction to the seat and the lid.

In a conventional toilet bowl, since solid pins are used for the hinges supporting the toilet seat and the toilet lid, the friction on the sliding contact portions between each solid pin and the pin insertion holes formed in the toilet seat and the toilet lid is likely to decrease. For that reason, the lid often unexpectedly closes due to its own weight causing an impact, when the lid, for instance, slips down out of the hand at the time of opening the lid. This impact closing of the lid may result in not only making an unpleasant noise but also damaging the toilet bowl. Such a tendency is greatly promoted as the sliding contact portions mentioned above wear, and such wearing is likely to occur, for the lid is generally opened or closed so often.

When a spring pin is used for a pivot, as mentioned in Japanese Patent 56-8607, the friction acting in the sliding contact poritions is automatically compensated for by the force of the pin which acts to expand the spring pin itself in the radial direciton, so that the lid is prevented from closing due to its own weight.

However, it has recently turned out that when a spring pin rotates excessively in the pin insertion hole or, when an abnormal axial force acts on the spring pin, the spring pin is forced to vibrate in the hole and slip forward in the axial direction of the spring pin and even unexpectedly drop out of the hole.

An object of the present invention is to provide a toilet bowl whose spring pin is effectively kept from dropping out of the pin insertion holes.

Another object of the present invention is to provide a toilet bowl in which adequate frictional resistance to the rotation is always applied to the hinge of the toilet seat and lid lest the seat and lid should unexpectedly close due to their own weight and causing an impact.

A further object of the present invention is to provide a toilet bowl in which the hinge devices do not begin to rattle or the pivots of hinges do not drop off even if the sliding contact portions wear due to the frequent use of the toilet bowl.

These objects and others are attained with a toilet bowl comprising a toilet bowl body; both a toilet seat and a toilet lid which are provided on the toilet bowl body; a pair of stationary members fixed at spaced apart positions on the toilet bowl body; a pair of pivotal supporting parts integral with the toilet seat and inserted between the stationary members; a pivotal supporting part integral with the toilet lid and inserted between the former pivotal supporting parts; a pair of three-element receiving insertion holes provided in each stationary member and the pivotal supporting parts of the seat and lid near each stationary member, respectively; and a pair of spring pins coaxially inserted into the three-element receiving insertion holes, respectively, whereby the seat and lid are hinged on the toilet bowl, characterized in that a wedge is tightly fitted in at least one end of each spring pin so that the end of the spring pin is fixed in the pin insertion hole.

Various other objects, advantages and features of the present invention will become readily apparent from the following detailed description, reference being made to the accompanying drawing in which:

FIG. 1 is an perspective view of a toilet bowl according to the present invention;

FIG. 2 is an axial sectional view of the hinge portion of a toilet seat and lid in a first embodiment according to the present invention;

FIGS. 3A, 3B and 3C are enlarged detail views illustrating the main steps of the assembly of the first embodiment;

FIG. 4 is an axial sectional view of the hinge portion of a toilet seat and lid in a second embodiment according to the present invention;

FIG. 5 is a detail view illustrating the main step of a process for integrally molding a stationary member and its pin insertion hole with a bushing end spring pin by injecting molten synthetic resin;

FIGS. 6A, 6B and 6C illustrate the main steps of the assembly of the second embodiment;

FIG. 7 is a partially-cutaway perspective view of a metal bushing;

FIGS. 8A, 8B and 8C show the shapes and dimensions of the main parts of a toilet hinge according to the present invention.

A toilet bowl in a first embodiment according to the present invention is hereinafter described referring to FIGS. 1, 2, 3A, 3B and 3C. As shown in FIG. 1, a pair of members 2 are fixed at appropriate points on the top of the toilet bowl body 1 by conventional fixing means. A pair of pivotal supporting parts 4 integrally formed on a toilet seat 3 and another pivotal supporitng part 6 integrally formed on a toilet lid 5 are located between the stationary members 2. These pivotal supporting parts 4, 6 form respectively the parts of hinges for the toilet seat 3 and the toilet lid 5, the pivots of which are formed by spring pins 7 formed as elongated thin walled cylindrical sleeve of uniform cross section and wall thickness .

As shown in FIG. 2, each stationary member 2 is provided with a pin insertion blind hole 10, and the pivotal supporting parts 4, 6 are provided with pin insertion throughgoing holes 11, 12. Cylindrical metal bushings 14, 15, and 16 made of stainless steel or the like are fixed in the pin insertion holes 10, 11 and 12 by force fitting, bonding or the like. Spring pins 7 are inserted into the metal bushings 14, 15 and 16 so that the pins extend through the bushings and are compressed in the radial direction against the bushings by the spring force. Therefore, the spring pins 7 are biased by their spring force into elastic contact with the inner surfaces of the metal bushings 14, 15 and 16. Each spring pin 7 shown in FIG. 2 has a wave-shaped slit 7a shown in FIGS. 3A, 3B and 3C.

A truncated-cone-shaped wedge 9 made of metal less harder than each spring pin 7 is tightly fitted into its end 7b at the stationary member 2, as shown in FIG. 2. Since the hardness of the spring pin 7 is designated as Hv 446 to 560 by the JIS B-2808, the wedge 9 is preferably made of mild steel of Hv 160 to 170 in hardness when the spring pin is made of spring steel. When the spring pin is made of stainless steel (JIS SUS420 J2), the wedge 9 is preferably made of the material prescribed by the JIS SUS304, whose hardness lies within Hv 160 to 170, processed by solid solution treatment. One end 7b of the spring pin 7 is expanded in the radial direction by the tight fitting of the wedge 9 so that the outer surface of the end 7b is very tightly fitted into the inner surface of the pin insertion hole 10. At that time, the wedge 9 is tightly fitted in up to its entirely cylindrical skirt 9a provided at one end, so that the wedge is fixed. Alternately, the wedge 9 may be tightly fitted in the other end of the spring pin 7 at the end by pivotal supporting part 6, or a pair of wedges 9 may be tightly fitted in both ends of the spring pin 7.

Since the pin insertion hole 10 is a blind hole, the wedge 9 can be tightly fitted instantaneously in one end 7b of the spring pin 7 when the end 7b is inserted into the metal bushing 14 inside of the pin insertion hole. To carry out such a process, the wedge 9 is first fitted half in the end 7b of the spring pin 7, as shown in FIG. 3A. The end 7b is then inserted into the pin insertion hole 10, so that the wedge 9 is brought into contact with the bottom 10a of the hole, as shown in FIG. 3B. The end 7b is thereafter inserted more deeply in the hole 10, so that the wedge 9 is fully and tightly fitted in the end 7b by the forced downward displacement of pin 7, as shown in FIG. 3C. This tight fitting can be very simply effected by hitting the other end of the spring pin 7 with a hammer 17.

The toilet bowl in a second embodiment according to the present invention is hereinafter described referring to FIGS. 4, 5 and 6. In this embodiment, a cylindrical closed end metal bushing 20 is provided instead of the open ended cylindrical metal bushing 14 in the first embodiment. To fix the metal bushing 20 in a stationary member 2, the bushing is first fitted tightly on one end of a spring pin 7 by a method mentioned below and is then stationary in the fixed member 2 by integral fuse-molding. In this case, the metal bushing 20 is held in a mold 23 comprising upper and a lower portions 21 and 22 and molten synthetic resin is poured into the mold through a sprue 24 so tht the stationary member 2 is formed and bonded to the metal bushing, as shown in FIG. 5. Since the metal bushing 20 has a closed end 20b, there is an advantage in that the molten resin does not enter into the bushing.

The spring pin 7 is fixed in the metal bushing 20 by utilizing the fact that the metal bushing is closed ended, as shown in FIGS. 6A, 6B and 6C. In this case, the wedge 9 is first fitted half in one end 7b of the spring pin 7, as shown in FIG. 6A. the end 7b is then inserted into the closed-bottomed metal bushing 20 so that the wedge 9 is brought into contact with the bottom 20b of the bushing, as shown in FIG. 6B. The end 7b is thereafter inserted more deeply in the metal bushing 20 so that the wedge 9 is fully and tightly fitted in the end 7b by the reaction, as shown in FIG. 6C. This tight fitting can be very simply effected by hitting the other end of the spring pin 7 with a hammer 17.

In the second embodiment, since the closed-bottomed metal bushing 20 is used as mentioned above, the quantity of the expansion of the bushing is very small although the wedge 9 is tightly fitted in the spring pin. In other words, the contact pressure between the outer surface 7b, of the spring 7 and the inner surface 20a of the metal bushing 20 is so high that the closed-bottomed bushing is firmly fixed on the end 7b of the spring pin, as shown in FIGS. 6. Therefore, it only the metal bushing 20 that is thereafter fixed in the stationary member 2, the spring pin 7 never dropping out of the pin insertion hole 10. The fixing of the metal bushing 20 in the stationary member 2 can be highly intensified if the outer surface of the metal bushing is provided with protrusions and recesses by knurling or the like as shown in FIG. 7. The metal bushing 20 fixed on the spring pin 7 may be secured in the pin insertion hole 10 by heating the bushing with a high-frequency heater to cause meltbonding. Otherwise, the metal bushing 20 may be secured in the pin insertion hole 10 bonding with an adhesive or by the like. If the stationary member 2 is made of metal, the metal bushing 20 may preferably be fixed therein by shrink fitting. The above-mentioned methods of fixing the metal bushing 20 in the pin insertion hole 10 can also be adopted not only to secure other metal bushings 15, 16 in other pin insertion holes 11, 12 but also to secure the metal bushing 14 in the first embodiment.

The results of experiments on a combination of a spring pin 7' and a bottomed metal bushing 20', both made of stainless steel, which have shapes and dimensions (a=7.07 mm, b=50 mm, c=15 mm, d=9 mm, e=7.00 to 7.01 mm) as shown in FIGS. 8A, 8B and 8C are hereinafter described. When the wedge 9 is tightly fitted in one end of the spring pin 7', the outside diameter of the end of the pin becomes 7.15 to 7.17 (mm). Therefore, the interference for tightly fitting the wedge 9 in the bottomed bushing 20' is 0.15 to 0.17 (mm). The torque required to break down the stationary member 2 made of ABS resin and fusebonded by integral moding on the closed-bottomed bushing 20' tightly fitted with one end of the spring pin 7' has been measured as 120 kg-cm. This proves that the stationary member fitted with the bushing endures practical use.

In the toilet bowl according to the present inventon, the spring pin, at least one end of which is fixed, is always elastically in tight pressure contact with the inner surface of the metal bushings. For that reason, adequate frictional force acts between the spring pin and the metal bushings to avoid such inconveniences such as the toilet seat and/or lid coupled to the metal bushings impulsively closing due to the weight of the seat and/or lid as soon as the hand opening or closing the seat and/or lid is separated therefrom.

Since the weight of the toilet seat 3 is 800 g or less and the its length is about 440 mm, the moment of gravitational rotation of the seat is not more than 0.8.times.44=35.2 kg-cm. The spring constant of the spring pin can be determined on the basis of the value of the moment. Because the value of the moment is low, the spring pin can be easily provided with an adequate spring constant which is necessary to obtain adequate frictional force.