EP0214246A1 - Seat for water tap - Google Patents

Abstract

In order to renew the seat of a domestic water tap, the valve actuation mechanism is removed, and the opening of the seat veil is reamed. An apparatus is then inserted into the valve, and an alignment device (30) is screwed into the valve body. In the alignment device (30) is arranged a withdrawal rod (25) at the bottom of which is attached a mandrel (20), a ferrule (40) being retained between the rod (25) and the mandrel (20). While the ferrule (40) is retained in the reamed opening, with its edge (41) resting on the canvas, the nut (50) is rotated, forcing the rod (25) and the mandrel (20) to withdraw upwards. The ferrule (40) is then firmly fixed in the opening and forms the new seat.

Description

SEAT FOR WATER TAP

THIS INVENTION relates to water faucets or taps and more particularly to the replacement of the seating of such a tap as hereinafter will be defined.

The conventional water faucet or tap is a fluid control valve of the type having a housing, usually cast metal but sometimes of moulded, high-impact rigid plastic, including inlet and outlet chambers separated by a web having an aperture through which water is able to flow. This flow between the two chambers is controllable by a closure member which is bodily movable to and from the aperture; the member is operated by a threaded spindle which extends through a co-acting threaded bore in the housing and is screwed down, by manipulation of a handle, so as to force the closure member, against the flow of water passing through the web aperture, onto a seating constituted by the annular peripheral region of the web immediately surrounding the aperture. Hereinafter such a fluid control valve will be referred to simply as "a tap of the kind defined".

A tap of the kind defined is subject to deterioration, pitting, etc. in the vicinity of the seating. Such deterioration mars the smooth upper surface of the web, abrading the washer on the closure member and impairing the effectiveness of the seating. These taps invariably leak and have to be either replaced or repaired. This invention is particularly applicable where access to the taps is limited, for example, when the leaking tap is embedded in a wall.

It has been proposed to effect a repair to such tap by fitting it with a new seating. The suggestion for doing this involves reaming out the aperture and tapping it to enable an externally flanged, threaded insert to be screwed into it; the flange extends radially away from one end of the insert to provide a new seating surface against which the closure member can seat.

However, it has been found to be difficult, in practice, to provide a new seating as described above as the web is often too brittle or too deeply pitted to withstand tapping a thread. Moreover, the aperture is very often not coaxially aligned with respect to the threaded bore in the housing, which makes it very difficult - if not impossible - to tap the aperture correctly. Because of these difficulties it is customary to discard such a damaged tap of the kind defined and replace it with a new one. It is therefore an object of the present invention to overcome the above and other disadvantages.

According to the present invention therefore there is provided a method of replacing a seating in a tap of the kind defined comprising the steps of:-

reaming out the web aperture of a said tap in coaxial alignment with the axis of rotation of the threaded spindle thereof by using an inserter to align the cutter;

inserting into said reamed-out aperture a cylindrical ferrule having, at one end thereof, an external annular flange and, at the other end thereof, an internal peripheral bead, said external flange being adapted to rest upon said web so as to constitute the said replacement seating, the said other end of the ferrule extending beyond the other side of said web;

passing through the interior of said ferrule a bead expander, said expander having an outside diameter less than that of the bore of said ferrule but greater than that of said internal peripheral bead: the arrangement being such that withdrawal of said bead expander through said ferrule bore causes the beaded other end of said ferrule to be deformed into intimate engagement with the rim of said aperture to thus lock said ferrule to said web.

In a second aspect of the present invention, there is provided a cylindrical ferrule fabricated from a material capable of being cold-drawn, resistant to deterioration by water, and capable of providing a seating in a tap of the kind defined, said ferrule having, at one end thereof, an external annular flange and, at the other end thereof, an internal peripheral bead; the outwardly-facing surface of said annular flange being capable of providing the said replacement seating, and said peripheral bead being capable of being deformed and expanded radially, by a cold-drawing technique, to thus enlarge the external diameter of the associated end of said ferrule while expanding the internal diameter of said bead to substantially the same as that of the bore of the remainder of said ferrule.

In a third aspect, the present invention provides apparatus for expanding a cylindrical ferrule for the replacement of a seating in a tap of the kind defined, said apparatus comprising an inserter member having, intermediate its ends, an externally threaded portion enabling it to be screwed into a co-operating, internally threaded socket in the housing of a said tap, one end of said inserter member being adapted to urge an external annular flange of said cylindrical ferrule into contact with the web of said tap as said inserter member is screwed into said socket; a withdrawing rod non-rotably slidable within said inserter member, one end of said withdrawing rod being provided with an internally threaded bore therein and the other end being formed as a threaded shank; a nut screwable onto said threaded shank to move said withdrawing rod axially through said inserter member; and a bead expander having, at one end thereof, a threaded spigot screwable into the bore of said withdrawing rod, a cylindrical intermediate portion adapted for insertion through said ferrule and, at the other end thereof, a frusto-conical portion the free end of which has a diameter greater than the internal diameter of an internal peripheral bead of said ferrule while being of substantially the same diameter as the bore of the remainder of said ferrule.

The preferred material for the cylindrical ferrule is stainless steel, ideally SAE 30:302 or 30:303F, and the most advantageous cross-section for the internal peripheral bead is that of the shape of a rounded tooth defined by a cylindrical surface extending between a radial surface constituting an end-face of the ferrule and a shoulder surface disposed at an angle of about 120 degrees to the interior wall of the bore of the ferrule.

In order that the reader may gain a better understanding of the present invention, hereinafter will be described a preferred embodiment thereof, by way of example only and with reference to the accompanying drawings in which:-

FIGURE 1 is a vertical cross-section through a water tap of the kind defined;

FIGURES 2A, 2B AND 2C are, respectively, a side elevation and end views of a bead expander according to the present invention;

FIGURES 3A, 3B and 3C are, respectively, a vertical half-section and end views of a withdrawing rod;

FIGURES 4A, 4B and 4C, are respectively, a vertical half-section and end views of an inserter member; FIGURES 5A, 5B and 5C are, respectively, a vertical half-section and end view of a cylindrical ferrule comprising the cylindrical ferrule;

FIGURES 6A, 6B and 6C are, respectively, a vertical half-section and end view of a nut;

FIGURE 7 shows, in section, an apparatus formed by the assembly of the parts shown in Figures 2A, B, C to 6A, B, C;

FIGURE 8 shows how the cylindrical ferrule is expanded by the bead expander; and

FIGURE 9 is an elevation corresponding to Figure 7, shown full size.

It is to be appreciated that a tap of the type illustrated in Figure 1 is designed for mounting externally to a substrate and that for economic reasons, it would be replaced in toto if seat deterioration caused it to leak. The present invention is particularly applicable to taps having a construction adapted to be substantially imbedded in, for example, a tiled wall, where replacement is very difficult. However the principle of operation is the same and will be described with reference to Figure 1.

Figure 1 shows a water tap 1 having a brass housing composed of a body 2 and a cap 3 both formed as brass castings which are screwed together at 4. The body 2 has a water inlet chamber 5 separated by a web 6 from a water outlet chamber 7 leading to a spout 8. It also provides a threaded socket 32. The web 6 is formed with an aperture 9 through which water passes between the two chambers when a closure member 10, associated with the aperture 9, is in its open position. The closure member 10 is of piston shape and is provided on its undersurface with a resilient sealing ring or washer 11 which engages a seat 12 formed as an annular machined surface on the web 6 surrounding the aperture 9.

The closure member 10 has a stem 13 which locates at its upper end in a recess 14 formed in the underside of a spindle 15 which has a threaded section 16 threadably engaging a threaded bore in the cap 3 of he housing. The upper end of the spindle 15 carries a handle 17 and is concentrically arranged with respect to the socket 32.

Over a period of time the web becomes brittle and the seat 12 becomes pitted. The sealing ring 11 is then unable to close the tap properly and it leaks in consequence. The loss of water and water pressure in the mains produced by such leakage is considerable and it is necessary to replace such leaky taps if they cannot be repaired.

Figures 2A to C show a bead expander 20, fabricated from hardened steel, having an intermediate cylindrical portion 22 disposed between an externally threaded spigot 24 and a frusto-conical, bead expanding portion 23 provided with a socket 21 for an allan key.

Figures 3A to 3C show a withdrawing rod, generally referenced 25, having an end portion 26 provided with an internally threaded bore 28 adapted to receive the spigot 24 of bead expander 20; withdrawing rod 25 has a hexagonal intermediate portion 26A.

The apparatus also includes an inserter member 30, as shown in Figures 4A to 4C, having an externally threaded portion 31 able to be screwed into the threaded socket 32 in the housing of tap 1 after the cap 3 has been unscrewed from the body 2 (see Figure 1) . Inserter member 30 has an end configured so as to constitute a hexagonal nut 33 and the other end terminating in a flat end-face 34. A bore 35 extends axially through inserter member 30 and is dimensioned so as to accept intermediate portion 26A of withdrawing rod 25 in a sliding fit. A nut 50 - to be seen in Figures 6A to 6C is screwable onto the threaded shank 27 of the withdrawing rod 25.

Figures 5A to 5C show a cylindrical ferrule 40 for the provision of a replacement seating for a tap of the kind defined. Ferrule 40 has an external annular flange 41, the outwardly-facing surface of which is capable of providing the said replacement seating, referenced 42. Surface 42 is preferably provided with an annular shoulder 42A to assist sealing. The other end of cylindrical ferrule 40 has an internal peripheral bead 44 having a cross-section of the shape of a rounded tooth defined by a cylindrical surface 46 extending between a radial surface 49 constituting an end-face of the ferrule 40 and a shoulder surface 47 disposed at an angle of about 120 degrees to the interior wall 48 of the ferrule.

The apparatus is assembled as shown in Figures 7 and 9. Cylindrical ferrule 40 is firstly slipped over bead expander 20 so that the internal peripheral bead 44 concentrically engages the frusto-conical portion 23. The stem 24 of the expander is screwed into the threaded bore 28 of the withdrawing rod 25 which is then inserted into inserter member 30 so as to bring the surface of flange 41 against end-face 34 of the inserter member. The inserter member is then screwed into the threaded socket in the tap housing after reaming out the web aperture in coaxial alignment with the spindle 15, so that the ferrule 40 is pushed into the aperture until its flange 41 is pressed against the marginal region of the surrounding web. The nut 50 is then tightened progressively so as to draw the expander through the ferrule and subsequently to expand the peripheral bead into intimate, locking engagement with that part of the web opposite to the seating region, as will be seen in Figure 7.

A sealant, such as an RTV silicon rubber, is then smeared over the outer surfaces of the cylindrical ferrule 40, before the inserter member 30 is screwed into the socket 32. Grooves, either axial or annular, assist the flow of sealant and also the keying of ferrule 40 in the web aperture. When the bead 44 is fully expanded and the replacement seating locked in position, the inserter member 30 is unscrewed from the socket 32 and the spindle 15, together with its closure member 10, 11 and the cap 3 replaced the tap is now ready for re-use.

While the above-described method and apparatus is intended principally for the replacement of seatings in taps of the kind defined, the same can be applied to new taps, being eminently suitable for mass production. Further, mass production techniques would employ other means of withdrawing the expander other than by screwing; preferably through the use of appropriate hydraulic equipment.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-

1. A method of replacing a seating in a tap of the kind defined, comprising the steps of:-

rearning out the web aperture of a said tap in coaxial alignment with the axis of rotation of the threaded spindle thereof by using an inserter to align the cutter;

inserting into said reamed-out aperture a cylindrical ferrule having, at one end thereof, an external annular flange and, at the other end thereof, an internal peripheral bead, said external flange being adapted to rest upon said web so as to constitute the said replacement seating, the said other end of said ferrule extending beyond the other side of said web;

passing through the interior of said ferrule a bead expander, said bead expander having an outside diameter less than that of the bore of said ferrule but greater than that of said internal peripheral bead:

the arrangement being such that withdrawal of said bead expander through said ferrule bore causes the bead-bearing other end of said ferrule to be deformed into intimate engagement with the rim of said aperture to thus lock said ferrule to said web.

2. The method as claimed in Claim 1, wherein, before insertion into said reamed-out web aperture, the outer surfaces of said cylindrical ferrule are coated with a sealant.

3. A cylindrical ferrule fabricated from a material able to be cold-drawn, resistant to deterioration by water, and capable of providing a replacement seating in a tap of the kind defined, said ferrule having, at one end thereof, an external annular flange, and at the other end thereof, an internal peripheral bead; the outwardly-facing surface of said annular flange being capable of providing the said replacement seating, and said peripheral bead being able to be expanded radially, by a cold-drawing technique, to thus enlarge the external diameter of the associated end of said ferrule while expanding the internal diameter of said bead to substantially the same as that of the bore of the remainder of said ferrule.

4. A cylindrical ferrule as claimed in Claim 3, fabricated from stainless steel.

5. The cylindrical ferrule as claimed in Claim 3 or Claim 4, wherein said internal peripheral bead has a cross-section of the shape of a rounded tooth defined by a cylindrical surface extending between a radial surface constituting an end-face of said ferrule, and a shoulder surface disposed at an angle of substantially 120 degrees to the interior wall of the bore of said ferrule.

6. Apparatus for expanding a cylindrical ferrule for the replacement of a seating in a tap of the kind defined, said apparatus comprising an inserter member having, intermediate its ends, an externally threaded portion enabling it to be screwed into a co-operating, internally threaded socket in the housing of a said tap, one end of said inserter member being adapted to urge an external annular flange of said cylindrical ferrule into contact with the web of said tap as said inserter member is screwed into said socket; a withdrawing rod non-rotably slidable within said inserter member, one end of said withdrawing rod being provided with an internally threaded bore therein and the other end being formed as a threaded shank; a nut screwable onto said threaded shank to move said withdrawing rod axially through said inserter member; and a bead expander having, at one end thereof, a threaded spigot screwable into the bore of said withdrawing rod, a cylindrical intermediate portion adapted for insertion through said ferrule and, at the other end thereof, a frusto-conical portion the free end of which has a diameter greater than the internal diameter of an internal peripheral bead of said ferrule while being of substantially the same diameter as the bore of the remainder of said ferrule.

7. The apparatus as claimed in Claim 6, wherein said inserter member has an internal bore of non-circular cross-section and wherein said withdrawing rod has, intermediate its ends, a portion of cross-section adapted to co-operate with the bore of said inserter member.

8. A method of replacing a seating in a tap substantially as described and with re^'ference to the accompanying drawings.

9. A cylindrical ferrule substantially as described and with reference to the accompanying drawings.

10. Apparatus for expanding a ferrule for the replacement of a seating in a tap substantially as described and with reference to the accompanying drawings.