[0001] Bathtub, provided with modularly arranged strengthening areas, in order to produce
a selfsustaining structure with so thin walls that the outside of the tub repeats
the inside thereof, allowing to pile-up, for storing and shipping, a plurality of
tubs.
[0002] Present invention pertains to bathtubs and in particular bathtubs manufactured from
plastic materials.
[0003] Today there is the use of manufacturing plastic material bathtubs for reasons of
low cost and easy working. The process used to be followed is that of vacuum thermoshaping
through which a plastic material sheet, for example from methyl metacrylate, usually
well stiff at ambient temperature as well as at the usual temperature of hot water
in a bathtub, is heated to the softening point and laid down against a hollow mold
by applying a vacuum at suitable points.
[0004] This process produces tub shells having excellent shape and finishing needing few,
if any, further working for having their ultimate appearance and the full utilizability.
[0005] The only serious problem with these so obtained shells is their intrinsic brittleness
or weakness, due to wall thinness, preventing their direct use in installations, as
said shells could easily open or crack even under relatively mild strains. A largerly
used remedy against this problems consists in exterally coating said shells by means
of glass fabric layers soaked by hardenable resins, such as polyesters, producing
a sustaining structure provided with substantial mechanical strenght in order to however
prevent damages to said shell, specifically the ones connected with the use of a bathtub.
[0006] This external coating with glass fabric layers soaked by hardenable resin has however,
further to give the external wall of the tub a poor aesthetic appearance, the serious
problem of raising the wall thickness thereof to the point to allow just a partial
entry of the external part of a tub in the internal part of another tub so that in
storing and shipping people are compelled to take into account an encumbrance similar
to a parallelepiped enclosing the same, with poor space use problems heavily affecting
said storage and shipping costs.
[0007] To avoid this excessive encumbrance problem should be devised bathtub shells with
such a selfsustaining structure to prevent substantial distortions thereof under usual
strains due to use or piling-up, but altogether so thin to allow piling-up with entry
of any shell in each other leading to both storage and shipping space substantial
economies. To allow a tub manufacture comprising a simple completely selfsustaining
shell characteried by having inserted a rib structure, consisting of a modular grid,
having the duty, of uniformely distribute in said shell the strains due to the load
of water and, possibly, or a person lying in said tub, said strains loading, by means
of said ribs or ridges, mainly supports under the bottom of said tub.
[0008] According to a first embodiment, said modular structure comprises a radial rib assembly
depending from a shell edge and joining in a point on the bottom thereof, said ribs
starting from points distributed on said shell edge in order to form a rectangular
grid with substantially uniform members having the duty of distributing the most uniformly
the possible said strains.
[0009] In particular, said ribs converging on the bottom are connected each other by curved
surfaces, either hollow or convex with respect to the shell inside, giving the shell
an appearance as of a sea shell and a particularly high strength.
[0010] Preferably, the curved surfaces connecting said ribs are arranged symmetrically
around a longitudinal axis of said shell with a hollow first major surface, symmetrically
divided by said longitudinal axis, going from the upper edge at the head side to the
convergence point of the ribs on the bottom of the shell, flanked by two hollow curved
surfaces in turn adjacent third hollow surfaces continuining in fourth surfaces, which
can be either hollow or convex, in turn continuing in fifth hollow surfaces adjacent
a last hollow surface symmetrically divided by said shell longitudinal axis at the
foot side of the tub.
[0011] More preferably said first hollow major surface is so shaped to form an anatomic
back.
[0012] Still more preferably, said two second hollow surfaces, adjacent said first hollow
surface, form niches delimited at half height by bottom planes forming two arms.
[0013] Further preferably, said fourth curved convex surfaces end as lowered with respect
to the tub edge forming two support planes symmetrically arranged with respect to
the longitudinal axis of the tub itself.
[0014] According to a second embodiment, said modular shell structure is formed by an assembly
of protruding and re-entring areas connected by ribs similar to the ribs sustaining
a boat planking, which are formed by connecting surfaces between said protruding
areas and said re-entring areas, said ribs being arranged in two substantially perpendicular
groups each other intersecting in order to form a rectangular grid having substantially
uniform members and having the duty of distributing the most uniformely the possible
said strains.
[0015] Particularly the areas protruding to inside said shell form as two substantially
perpendicular bands of which a first major band is parallel and symmetric with respect
to a longitudinal axis of said shell and a second minor band is substantially perpendicular
with respect to said first major band intersecting it at a place substantially near
the foot side of said shell.
[0016] More preferably, said first major band is shaped at the head side of said shell in
order to form an anatomic back.
[0017] Still preferably, two re-entring areas adjacent said major band at head side are
provided with two niches delimited at half height by bottom planes forming two arms.
[0018] Further preferably, said second protruding minor band ends against the edge of the
tub with two lowered areas forming two support planes symmetrically arranged with
respect to the longitudinal axis of the shell itself.
[0019] The features and the advantages of the present invention will be made more apparent
by the following detailed description of its embodiments, not given in limiting sense
provided with the enclosed drawings, wherein:
figure 1 is a diagrammatical perspective view of a selfsustaining tub shell structure
according to a first embodiment of present invention;
figure 2 is a diagrammatical perspective view of selfsustaining tub shell structure
according to a second embodiment of present invention;
figure 3 is a perspective view of an installed bathtub formed by a selfsustaining
shell of the first embodiment;
figure 4 is a perspective view of an installed bathtub formed by a selfsustaining
shell of the second embodiment.
[0020] Considering the first embodiment and particularly figure 1, it is seen that the first
tub 10 embodiment, having selfsustaining walls according to the present invention,
consists of a shell 12, formed for example by vacuum themoshaping of a thermoplastic
material sheet, comprising an edge 14 according to a substantially rectangular frame
from which depends a hull 16 forming the part of the tub intended to contain the water.
From the edge 14 along the internal walls of the tub depend ribs or ridges 18a-l which,
starting from points 20a-l on the edge of the hull 16, descend to a connection area
22 usually strengthened for housing accesories such as the tub drain. The points
20a-l are arranged in order to lay on a grid having rectangular substantially regular
loops formed by intersecting straight lines 24a-e which provides a substantially
uniform distribution of the strains on the hull 16 due to the presence of water and/or
of the body of a person in the tub 10. Of course, said tub 10 abuts in a usual way
with its bottom and edge 14 on a structure 26, such as a brick wall structure tiled
or panelled, and also on the floor of the room in which the bathtub is installed.
[0021] Considering now the second embodiment of this tub and particularly figure 2 in this
case a selfsustaining wall tub 30 according to the present invention consists of
a shell 32 also formed by vacuum thermoshaping from a thermoplastic material sheet,
comprising an edge 34 according to a rectangular fram frome which a hull 36, forming
the part of the tub intedend to contain water, descends.
[0022] The internal walls of the hull 36 have two inside protruding areas of which a first
major area or band 38 is arranged parallel and symmetric with respect to a longitudinal
axis 39 of the tub itself and a minor area or band 40 is sustantially perpendicular
with respect to the major area 38 crossing the same near the foot side of the tub.
The two band areas 38 and 40 delimit adjacent lowered areas 42a-f, of which two areas
42b and 42e have intermediate depth and four areas 42a, 42c, 42d, and 42f are the
deepest, forming among them rib connections 44a-l having a strengthening duty similar
to that of the ribs of a boat hull. The rib connections 44a-l are in line with straight
lines 45a-e crossing each other to form a grid having rectangular uniform loops providing
a substantially uniform distribution of the strains applied to the hull 36 by the
presence of water and/or the body of a person in the bathtub itself.
[0023] Of course, said tub 30, showing on the external wall of its hull 36 re-entring band
areas 46 and 48 respectively corresponding to band areas 38 and 40 inside protruding,
abuts in a usual way with its bottom and the edge 34 against a structure 50, such
as a brick structure, tilable or panelable for aesthetic purposes, as well as on the
floor of the room in which the bathtub is installed.
[0024] From the review of figures 1 and 2 it appears that in both the tub embodiments the
external walls of the respective shells 12 and 32 repeat substantilly on the contrary
the internal walls, in the sense that to protruding members in the internal walls
correspond re-entring members in the external walls and viceversa. This fact allows
to superimpose and entry one into the other the shells 12 or 32 of similar kind which
can be each other piled-up without damages with the simple interposition on thin antiscratch
material sheets in order to use at most the room in stores and shipping means. For
example, these shells 12 and 32 lend themselves very well to storage in compact packages
and to shipping in standard modular containers allowing their maximum filling.
[0025] Referring now to figure 3 it is seen an installed bathtub having ribbed shell embodied
according to figure 1 example.
[0026] In a corner of a bathroom between two tiled vertical walls 60 and 62 and also a tiled
floor 64, is installed a bathtub manufactured according to the tub 10, having the
ribbed shell 12 of figure 1.
[0027] Said tub, surrounded and supported by a brick structure, defined by the tiled walls
66 and 68, comprises a rectangular frame edge 74 from which descends a ribbed shell
76 provided with ribs protruding to the inside indicating the limits among hollow
surfaces such as the surfaces 78a-h, or between hollow and convex surfaces, such as
the surfaces 80a and 80b terminating a little below the rectangular edge 74 for defining
two article support planes 82a and 82b.
[0028] Further, the hollow surfaces 78b and 78h are formed as deep niches housing, at half
height, support planes having duty of arms 84 and 85 and the hollow surface 78a is
so shaped to form an anatomic back affording particular comfort to the bathtub.
[0029] Referring at last to figure 4, it is seen an installed bathtub having a ribbed shell
according to the embodiment of figure 2.
[0030] In a corner of a bathroom between two vertical tiled walls 60 and 62 and an also
tiled floor 64 is installed a bathtub manufactured according to the tub 30, having
ribbed shell 32 of figure 2. Said tub, surrounded and supported by a brick structure
defined by the tiled walls 66 and 68, comprises a rectangular frame edge 94 from which
descends a ribbed shell 96 provided with a first major raised band area 98 arranged
according to the length of the tub, and with a second minor raised band area 100 substantially
perpendicular with respect to the major band area 98, said band area 100 terminating
with two planes 102a and 102b a little below the frame 94 operating as article supporting
planes.
[0031] At the head side of the tub the raised band 98 is surrounded by two lowered niches
104a and 104b, terminating at half height with two planes 106a, and 106b, operating
as arms.
[0032] Similarly at the foot side there are two lowered areas 108a and 108b delimited by
the two raised bands 96 and 100. On the bottom of the tub the lowered areas prosecute
delimited by the raised bands 98 and 100 for assuring the presence of strenghtening
ribs in the whole tub. The major raised band 98 is shaped at the head side to form
an anatomic back 110 affording particular comfort to the tub.
[0033] A further thickness step 112 at half height supplies a supplementar or izontal rib
further cooperating to strengthen the shell 96.
[0034] What has been hereabove stated depictes two embodiments of the invention, given in
not limiting sense, and it will appear to those skilled in the art fully equivalent
changements, alterations and substitutions, to be considered here covered.
1. Bathtub, having self sustaining walls, formed by a single shell, characterized
by having provided a strengthening rib or ridge structure consisting of a modular
grid, having the duty of uniformely distribute in said shell the strains due to the
load of water, and possibly of a person lying in said tub, said strains loading, by
means of said ribs or ridges, mainly supports under the bottom of said tub.
2. Bathtub, according to claim 1, characterized in that said shell (12) modular structure
comprises a radial rib assembly (18a-l) depending from a shell edge (14) and joining
in a point (22) on the bottom thereof, said ribs (18a-l) starting from points (20a-l)
distributed on said shell edge (14) in order to form a rectangular grid with substantially
uniform members having the duty of distributing the most uniformly the possible said
strains.
3. Bathtub, according to claim 2, characterized in that said ribs (18a-l) converging
on the bottom are each other connected by curved surfaces, either hollow or convex,
giving the shell (12) an appearance as of a sea shell and a particularly high strength.
4. Bathtub, according to claim 3, characterized in that the curved surfaces connecting
said ribs (18a-l) are arranged symmetrically around a longitudinal axis of said shell
(12) with a hollow first surface (78a), symmetrically divided by said longitudinal
axis, going from the upper edge (14) at the head side of the tub to the convergence
point (22) of the ribs (18a-l) on the bottom of the shell (12), flanked by two hollow
curved surfaces (78b, 78h) in turn adjacent third hollow surfaces (78c,78g), continuing
in fourth surfaces (80a, 80b), which can be either hollow or convex, in turn continuining
in fifth hollow surfaces (78d, 78f) adjacent a last hollow surface (78e) symmetrically
divided by said shell (12) longitudinal axis at the foot side of the tub.
5. Bathtub , according to claim 4, characterized in that said first hollow major surface
(78a) is shaped to form an anatomic back (86).
6. Bathtub, according to claim 4, characterized in that said second hollow surfaces
(78b, 78h) adjacent said first hollow surface (78a) form niches delimited at half
height by bottom planes forming two arms (84,85).
7. Bathtub, according to claim 4, characterized in that said fourth surfaces (80a,
80b), if convex end as lowered with respect to the edge (14), of the tub forming two
support planes (82a, 82b) symmetrically arranged with respect to the longitudinal
axis of the shell (12).
8. Bathtub, according to claim 1, characterized in that said modular shell (32) structure
is formed by an assembly of protruding areas (38, 40) and re-entring areas (42a-f)
connected by ribs (44a-l), similar to the ribs substaining a boat planking, which
are formed by connecting surfaces between said protruding areas (38, 40) and said
re-entring areas (42a-f), said ribs (44a-l) being arranged in two substantially perpendicular
groups each other intersecting in order to form a rectangular grid having substantially
uniform members and having the duty of distributing the most uniformely the possible
said strains.
9. Bathtub, according to claim 8, characterized in that the areas (38, 40) protruding
to inside said shell (12), form as two substantially perpendicular bands of which
a first major band (38) is parallel and symmetric with respect to a longitudinal
axis (39) of said shell and a second minor band (40) is substantially perpendicular
with respect said first major band (38), intersecting it at a place substantially
near the foot side of said shell (12).
10. Bathtub, according to claim 9, characterized in that said first major band (38,
98) is shaped at the head side of said shell (32) in order to form an anatomic back
(110).
11. Bathtub, according to claim 9, characterized in that two re-entring or lowered
areas (42a-f) adjacent said major band (38, 98) at the head side are provided with
two niches (104a, 104b) delimited at half height by bottom planes forming two arms
(106a, 106b).
12. Bathtub, according to claim 9 characterized in that said second protruding minor
band (40, 100) ends against the edge (34, 94) of the tub with two lower areas (102a,
102b) forming two support planes symmetrically arranged with respect the longitudinal
axis of the shell (12) itself.