This invention relates to a shower hose, intended to be mounted between a tap valve affixed with respect to a wall and a loose shower head, said hose being made in plastic tube material and being coiled into spiral shape, the stiffness and elasticity of the tube material being chosen such that the hose, while maintaining its spiral shape as a whole, is extensible according to the spiral axis and will subsequently return again into its original condition. Most of the known shower hoses can be distinguished into three types. Most simple and cheap is a hose made in soft plastic material, generally PVC. With the second type the tube wall of plastics material is made around a spiral shaped metal reinforcement. With the third type the tube wall is constructed of a spiralized metal profile, usually called a Z-profile, having bent edges which are alternating- ly directed outwardly and inwardly, and which are inter- engaging. Sealing is assured by a continuous plastics layer at the inside and/or the outside of this metal core. Although the lastmentioned type is the most solid of the three, in practice it only has a life of a few years. After this time period the same phenomena will occur as are observed with hoses of the first and second types : tears in circumferential direction will occur as a result of kinking- loads, usually close to the connection nipples with the tap valve and the shower head.

DE-A-3 434 735, upon which the heading of claim 1 is readable, quoted above in the first paragraph, discloses a further development in so far as it deviates from the idea of maintaining an overall cylindrical shape of the hose and instead proposes to coil the cylindrical tube into a spiral shape, which spiral has an overall or outer diameter which is so small that the coiled tube, in its retracted state, can be housed in a cylindrical element. In case of the hose for a shower head such housing is the hollow interior of

the handle of the shower head. The cited patent application discloses other embodiments of this basic idea where the spiral tube is used as an interconnection between a tap valve armature and an outlet spray in a kitchen sink. With this and similar embodiments the coiled tube is housed in some special cylindrical space which constutes part of the armature or of the sink, so that only during actual use a spraying head or a similar piece presenting an outlet aperture can be moved a certain distance from the armature and after use, by virtue of the resiliency of the coiled tube, the tube will return into its housing. In view of these considerations the spiral outer diameter with this prior art idea is 2 cm or less.

The.shower hose acording to the present invention is characterized in that with an external tube diameter (d) of about 10 mm, the external spiral diameter (D) has a value between 4 and 12 cm.

This is an idea which is entirely different from the principles discussed in the abovecited DE-A-3 434 735 in so far as it does not seek to hide the spiral hose. To the contrary, the spiral outer diameter is made so big that it is virtually impossible, in any structure which would meet esthetical design requirements, to house it in some enclosure. This spiral hose is always visible, particularly also in the position in which it is not in use. It is con¬ templated that, when the shower head, when not in use, is hung onto the hook which has the function to support it, the spiral shape will constitute a decorative element in the bathroom. Additional advantages over the prior art spiral hose are the fact that the spiral, at the larger diameter pro¬ posed according to the invention, can be more easily manufactured. Also, because there are no size limitations anymore, the inner and outer diameters of the tube material proper are not under any limitations imposed by limitations on the housing which the prior art armature or shower head

presented; in other words: it can easily carry a greater flow rate of water.

Preferbly the external spiral diameter (D) has a value between 6 and 8 cm. For all practical purposes, particularly in view of th esthetical considerations given above, it deserves prefe¬ rence that the spiral, in its undeformed condition, has a length between 30 and 50 cm.

The cited German patent application contemplated the use of metal covered externally or internally with plastic material, and also plastic material alone. The present invention has a clear preference for plastic material alone Particularly as a result of the larger diameters which the invention proposes, the loads, especially the kinking loads are less severe, so that there is no reason anymore to use metal reinforcements.

As regards the materials, the invention has two clear preferences. One preferred material is thermoplastic poly- urethane. Another preference is a polyamide, particularly Nylon 11 or Nylon 12.

It is pointed out that spiral tube material is known also outside the field of sanitary installations. It is (se US-A-3 021 871) used in the art of pneumatics, as a connec¬ tion between the engine part and a trailer in vans, in the high pressure air system for the breaks. It is also used to couple parts of hydraulic systems.

The invention will be explained with reference to the accompanying drawing of an embodiment.

The single figure shows in elevation a tap valve and a shower head, interconnected by a coiled hose according to the invention.

Against a wall 1 a mixing tap 2 has been mounted, provided in known manner with cap nuts such as 3 and rosettes such as 4 on the supply lines for hot and cold water, respectively.

At the front there are turning knobs such as 5 for the water as well as a change-over knob 6 for changing over the

flow of water between the discharge opening 7 at the bottom of the tap and the shower connection 8 provided at the top thereof.

The showerhead 9 is, also in known manner, supported by a bracket 10 which, by means of a sliding piece 11 provided with a fixation knob 12, is slidable over rod 13 which has fixation heads 14, 15 for fixation against the wall.

Between tap valve 2 and shower head 3 there is the shower hose according to the invention, generally indicated by 16. This hose comprises a tube, made in plastics material which, as a whole, has been coiled into spiral shape.

Starting from an external tube diameter d of about 10 mm - which, with a wall thickness of between 0.5 - 2 mm, preferably between 1 and 1.5 mm, leaves an internal tube diameter which is appropriate for practical use - the external spiral diameter D is at most 20 x d. In the embo¬ diment represented the actual diameter d is exactly 10 mm and D about 7 cm.

There has been represented a slightly extended condi- tion of the spiral hose 16. Starting from the fact that usually the lower fixation point 15 of slide rod 13 is chosen about 50 cm above tap 2, the length of rod 13 being mostly between 75 cm and 1 m, dimensions fit for practical use are obtained when spiral 16, in its undeformed condi- tion, presents a length between 30 and 50 cm, in which con¬ dition the individual coils of the spiral will touch or almost touch each other. A practical embodiment has a length of spiral - when the individual coils of the spiral touch, and excluding the end parts 18, 19 yet to be described - of 35 cm.

The stiffness and resiliency of the tube material are selected so that the hose is extensible according to its axis 17, while maintaining its spiral shape, up to at least double its original length, whilst, after removing the extending force by displacing shower head 9 relative to tap valve 2, it will return again to its original condition. As an appropriate material for the spiral tube the

invention prefers a thermoplastic polyurethane (TPU). Also polyamides might be. used, with Nylon 11 and 12 being quite appropriate. These materials combine a great strength with an appropriate stiffness and resiliency. It is also being said that these materials "have a memory", at least under normally occurring variations in room temperature, to return to their original shape.

The two end parts 18, 19 of the hose do not continue i the shape of the spiral but are shaped such that at least they extend parallel to the spiral axis 17, but preferably extend substantially according to this axis. Thus moments are prevented which otherwise, when extending the spiral relative to its rest condition, might occur relative to the fixation points, particularly relative to the cap nuts. Both on top and below the hose is preferably according to the invention provided with a nipple 20 and 21, respectively, of a commercially available type, which presents two special features. Firstly it includes internally a quick action coupling, by means of which it clamps itself as soon as a tube is inserted into it. Secondly this internal coupling is realized as a cap nut which, therefore, is able to rotate freely, with the clamped hose, relative to the nipple's cap nut portion 20' which is tighted completely onto the exter¬ nal thread provided on the connection stump of the shower head and the tap valve, respectively (including a provision for watertightness, as a matter of course).

The hose according to the invention is generally fit to be used with all tap valves having the connection 8 for the shower hose on top of the fittings. In case of a combined bath and shower tap, as shown, the knob such as 6 for changing the water flow over between the discharge opening 7 for the bath and the discharge opening 8 for the shower, will be situated at the front. Also tap valves exist in which the lastmentioned knob is situated on top, the connection such as 8 for the shower hose being provided on the lower side of the fittings. For this type of tap valve the hose according to the invention is less appropriate. The

considerable deformation of the spiral when, in order to hang the shower head such as 9 in the regular manner, the hose must make a very short bend from below around one of the sides of the tap valve upwardly, and be borne by the material without any problem, particularly when any of the above entioned materials is used, but this course of the spiral will generally be experienced as less pretty and in conflict with esthetic considerations which may have been decisive for the user in choosing a spiral shower hose.