WO1988008762A1

WO1988008762A1 - A process for the production of hard surface control members for faucets

Info

Publication number: WO1988008762A1
Application number: PCT/US1988/001487
Authority: WO
Inventors: Alfons Knapp
Original assignee: Masco Corporation Of Indiana
Priority date: 1987-05-12
Filing date: 1988-05-06
Publication date: 1988-11-17
Also published as: DK729288D0; IT1210727B; FI890128A; DK729288A; GB8829103D0; FI96827B; FI890128A0; IT8767407A0; ES2010542A6; GB2211444B; EP0314757A4; DK167478B1; GB2211444A; DE3890357C2; JPH01503769A; EP0314757A1; FI96827C

Abstract

A process for the production of hard surfaced control members for faucets, in which the body of the control member is made of aluminum or its alloy. The working surface of the control member is submitted to anodic oxidation in such a way that a layer of aluminum oxide is generated. This layer of aluminum oxide is then subjected to lapping until it has a finish which is adequate for its function as a seal. Finally, this layer of aluminum oxide is impregnated with a substance which is adapted to fill most of the pores. From this process, which is economical and technologically easy to carry out, results a control member for faucets that has a body essentially made of aluminum or its alloy. Further, the working surface is made of a layer of aluminum oxide, that strongly adheres to the metal body, which is worked until it has a smooth finish. The pores of this porous structure are then occluded by an impregnating substance. This member can have liberally chosen forms that show superior functional characteristics.

Description

A PROCESS FOR THE PRODUCTION OF HARD

SURFACE CONTROL MEMBERS FOR FAUCETS

Background of the Invention

I. Field of the Invention

The present invention relates to the production of hard surfaced control members for faucets.

II- Description of the Prior Art

For a long time, pairs of small plates or disks of hard material have been used as control members in fau¬ cets, whether simple faucets or mixer faucets. These pairs of small plates of hard material include a fixed small plate* that allows one or more openings for the flow of liquid, and a movable small plate which moves when it comes into contact with the fixed small plate. This move¬ ment is achieved by means of maneuverable actions. The movable small plate has apertures and/or a properly out¬ lined perimeter so that shifting it exposes, partially closes, or totally closes one or more of the openings of the fixed small plate thereby controlling the flow of the liquid through the faucet. Until now, the small plates have been in the form of masses of hard, so-called ceramic material, including oxides, silicates or carbides of vari¬ ous elements, that can be formed into the required config¬ urations through sinterization of the corresponding pow¬ der, and then subjected to lapping on their work surfaces. These work surfaces can also be subjected to particular treatments. For example, the work surfaces can be covered with material of even greater hardness, through physical deposition or chemical deposition by vapor. Further, the work surfaces, which are porous, can be impregnated with a lubricating substance.

However, the small plates which are produced in the above noted ways are not satisfactory in some points of Z view. In particular, their production through sinterization from ceramic powder allows a notable per¬ centage of waste and puts grave limitations on the forma¬ tions which are economically obtainable — practically so limited that only planar small plates of a simple form can be made. The fact that the ceramic material used to form the seal and the resistance to attrition of the work sur¬ faces makes up the entire mass of the small plates, makes the small plates, themselves, not very resistant to break¬ age and contributes to the fact that not many formations are obtainable. The low resistance to breakage is partic¬ ularly felt when the small plates are produced with porous materials, in order to reduce the area of contact between the cooperating small plates, and thereby reducing the friction between them. In particular, the fact that the hard surfaced control members for faucets can only be re¬ alized in the form of small plates that are planar must be considered an unacceptable limitation. Further, from the functional point of view, some control members have cylin¬ drical, conical or spherical work surfaces, for example, some taps which turn and slide axially, or some hemispher¬ ical distribution members, which would be desirable in many cases.

Summary of the Present Invention

The purpose of the present invention is that of cre¬ ating a new process, which is technologically and economi¬ cally convenient, for the production of hard surfaced con¬ trol members for faucets and to create a new kind of seal -member which-.is exempt from the disadvantages of the past known small plates made of hard material. It is also de¬ sirable to be able to choose the form of these control members liberally without being tied to a planar configu¬ ration.

This goal is reached, according to the present inven¬ tion, by means of a process in which: - the body of the control member for faucets is manu¬ factured, essentially in the required form, of aluminum or its alloy;

- the work surface of the manufactured body is then submitted to anodic oxidation under such conditions that an adequately thick layer of aluminum oxide is generated?

- the layer of aluminum oxide is subjected to lapping until it has an adequate finish to function as a seal;

- and finally the layer of aluminum oxide is impreg¬ nated with a substance that is adapted to substantially fill the pores thereof.

It should be noted that the order of the last two op¬ erations can be interchanged.

Detailed Description of a Preferred Embodiment of the Present Invention As a result of the process described herein, a con¬ trol member for faucets is made which has a body formed essentially of aluminum or its alloy, and a working sur¬ face which is made from a thin layer of aluminum oxide that strongly adheres to the metal body. The surface is worked on until it has a high level of finishing; further, this surface has a porous structure and its pores are oc¬ cluded by an impregnating substance.

The fact that the body of the control member is made of aluminum or its alloy permits the easy and economical manufacture of any desired form with ordinary means of metallurgic and mechanical processing, and assures that the control member has a great mechanical resistance against damage and breakage. The layer of aluminum oxide made through anodic oxidation adheres, as noted, very strongly to the metal body and does not present a problem of separation. The aluminum oxide produced in this way has an increased hardness, which is able to reach that of a corundum, and is particularly adapted to form a hard work surface on the control member. Further, the aluminum oxide produced in this way has an essentially porous structure, with pores extending prevalently in a perpendicular direction to the surface, and it is there¬ fore adapted to offer an area of contact that is reduced in the cooperation with another control member. Finally, the impregnating substance with which the layer of alumi¬ num oxide is impregnated assures an adequate seal of the small plates, despite the presence of a highly porous structure, and prevents the formation of calcareous depos¬ its in the pores.

There are diverse metallurgic processes which can be used in order to make the body of the small plates. Some that can be cited are: shearing, pressing, coining that start with a slab to produce members in the form of a small plate, as well as pressure casting, precision cast¬ ing, particularly adapted to manufacture members which have more complex forms. Also, for the attainment of hol¬ low control members like jaws, sheaths or liners, the pro¬ cesses of boring, broaching and calibrating through plas¬ tic deformation can be used. In the application of the present invention, these diverse processes are facilitated by the excellent workability of the aluminum or its alloy. Any of these processes can be conveniently chosen depend¬ ing on the desired configuration of the control member and the extent of the foreseen production in order to assure both the attainment of the best technical results as well as a low cost of production. In the cases in which the chosen formation process does not assure the attainment of a work surface which is sufficiently precise, smooth and regular, before proceeding with the operation of anodic oxidation, this surface, on the metallic body produced, can be mechanically worked until a proper grade of finish¬ ing is achieved.

As material for formation of the body, aluminum — pure or an alloy of aluminum with copper, silicon, magne¬ sium, manganese, titanium or other metals — can be used, the choice being dependent upon the process of production adopted and also by any corrosion resistance requirements. The anodic oxidation of the work surface can be done through electrolytic treatment in an acid or alkaline bath with one of the numerous processes known to achieve such a goal. For example, a bath of sulfuric acid at a concen¬ tration of 15%, or a bath of organic acids with added salts of titanium, thorium, zirconium, with an electric current of an intensity to produce a potential difference of between 12 and 22 volts. Having the goal to obtain a protective layer on the aluminum, the common treatment usually is to interrupt the anodic treatment upon obtain¬ ing a layer of aluminum oxide which is a few one hun- dredths of a millimeter thick. In the foreseen applica¬ tion of the invention, a layer of aluminum oxide of this limited thickness is utilizable only if the initial work surface of the metallic body is sufficiently precise, smooth and regular so that the lapping process can be lim¬ ited to the removal of a very thin layer of the aluminum oxide coating. If instead the initial metallic body is not sufficiently finished, the anodic treatment must be prolonged until a thicker layer of aluminum oxide is formed; for example, until it reaches a few tenths of a millimeter. This allows subsequent processing through lapping, with the removal of a relatively thick layer of aluminum oxide.

As noted, the technique of anodic oxidation offers the necessary means to regulate the thickness of the alu¬ minum oxide produced and to regulate the porosity — whether one wants to regulate the absolute dimensions of these pores or to regulate the percentage of surface occu¬ pied by the pores themselves — through a proper selection of the composition of the bath, its temperature, the in¬ tensity of the electric current and the duration of the treatment. Therefore, the proper coating that is consid¬ ered most desirable for the layer of aluminum oxide can be obtained by regulating the known parameters of treatment so that the best results can be obtained. The operation of lapping does not differ from that which is used on the small plates of ceramic material, when the control members have the form of small plates with planar surfaces. It takes on an analogous character to the process used on crystal lenses when the work sur¬ faces have cylindrical, conical or spherically convex forms. It is also similar to the process used on hydrau¬ lic cylinders or on internal combustion engines when the work surfaces have a concave form. There are no particu¬ lar problems posed by the processing of aluminum oxide produced through anodic oxidation. However, such process¬ ing could be done according to procedures which are, in temselves, well known techniques. As already mentioned, the operation of lapping can be limited to the removal of a very thin layer of aluminum oxide, in the cases in which the work surface, after the operation of anodic oxidation, is already notably precise, smooth and regular. Such op¬ erations must be done more deeply when there are correc¬ tions that must be made for defects in the parts or in the planarity or when there is an excessive unevenness of the resulting surface from the anodic oxidation.

The impregnation with an impregnating substance to fill the pore spaces which naturally exist in the struc¬ ture of the aluminum oxide coating, can be accomplished by using one of the various processes of impregnation which are well known. These processes immerse the parts that are to be impregnated in a bath of the impregnating sub¬ stance — ^'■ reduced to a sufficiently fluid state, if neces¬ sary, through heating, dissolving or diluting, under a vacuum or under sufficiently elevated pressure — to as¬ sure the penetration of the impregnating substance into the pores of the layer of aluminum oxide. The impregnat¬ ing substance can also be applied, through chemical reac¬ tion or physical deposition, directly into the pores of the layer of aluminum oxide. This way of processing is particularly advantageous when one wants to use a solid substance as the impregnating material. Regarding the choice of the impregnating substance, it must be said that an extensive choice exists because it is not required that this substance have a particular characteristic. Its function of occupying the pores of the layer of aluminum oxide is essential, on one hand, to assure the hydraulic seal of the control member which could be compromised by porosity that is too extensive, and above all to prevent calcareous deposits on the inside of the pores as a result of the water that is running through the faucet. In fact, it must be considered that the progressive increase of the friction coefficient by the control members in faucets principally depends on the formation, in their pores, of calcar deposits that, in time, will cause an unevenness of the work surface. Above all, to efficiently prevent the formation of deposits like these, it .is necessary that the impregnating substance oc¬ cupies most of the pores, is firmly anchored in the pore and not being able to escape from them with time. On the other hand, the impregnating substance must not be one that causes an increase in the friction coefficient. Nat¬ urally, it is not bad if the impregnating substance has some lubricating properties but it is not specifically re¬ quired because such properties are not utilized in that this substance must go into the pores and remain there without being able to go between the cooperating surfaces of the control members to reduce the friction coefficient. Finally, the impregnating substance must be physically and chemically resistant to contact with water including the hot water that can run from the faucet. Having in mind that the foregoing requirements must be met, it can be un¬ derstood that the impregnating substance can be chosen from a wide variety of materials. Thus, one can choose synthetic resins belonging practically to all the known groups, waxes, hydrocarbons, halogenated hydrocarbons, silicons; and also, liquid, semi-liquid or solid substanc¬ es; for example, graphite, molybdenum sulfide, amorphous or crystalline silicon. In the cases in which the presence of the impregnat¬ ing substance acts favorably or at least does not disturb the operation of lapping; or in the cases in which this last operation is conducted in such a way that the lapping operation is not disturbed by the presence of the impreg¬ nating substance, the operation of impregnation can also be done after the anodic oxidation treatment and before the lapping operation, or vice versa. In the case in which the impregnating substance is solid and is produced directly in the pores through a chemical reaction or a physical deposition, it becomes particularly convenient to proceed first with the operation of impregnation and then with the operation of lapping. In this way, the lapping gives rise to an essentially uninterrupted surface that is, in part, made from aluminum oxide, and in part from the impregnating substance that fills the pores of the aluminum oxide.

As a result of the application of the concepts of the present invention, the advantages of the use of hard sur¬ faced control members can be extended. Besides being used in faucets as control members of the small plates, they can also be used in faucets as other types of control mem¬ bers. For example, they can be used as control members of taps which turn or slide or have the ability to make both such movements, cooperating with sheaths, liners or jaws. Further, they can be used as distribution members in the form of spherical caps cooperating with a spherically con¬ cave site. In every case the process can be applied, de¬ pending on the circumstances, to both of the cooperating control members, or to only one of them. In other words, a control member, having all the characteristics of the invention, can cooperate with another control member which also has all the characteristics of the invention, or it can cooperate with another control member of a traditional structure, or one which has only one part of the charac¬ teristics of the present invention, like a member having a body of aluminum or its alloy and a work surface that is anodically oxidized and lapped, but not impregnated with an impregnating substance.

In the case of control members of various form for small plates, the application of the invention gives the control members mechanical resistance against breakage, excellent sealing characteristics, great fluency and dura¬ bility for long use. The freedom of shaping the control members provides a favorable effect on the planning of the entire faucets.

The invention not only concerns the stated process of production, but also the control members, having a charac¬ teristic structure, that result from the described process in addition to the faucets that use control members which have all or some of the stated characteristics.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limita¬ tions should be understood therefrom as some modifications will be obvious to those skilled in the art without de¬ parting from the appended claims.

I claim:

Claims

1. A process for the manufacture of hard surfaced fluid control members for faucets comprising the steps of: forming the main body of said control member for fau¬ cets of an aluminum-based metal; coating said main body through anodic oxidation with a layer of aluminum oxide; lapping said layer of aluminum oxide to form a fin¬ ished surface adapted to function as a seal; and impregnating the pores of said aluminum oxide layer with a filler material.

2. The process as defined in claim 1 wherein said main body is formed by a metallurgical process selected from the group consisting of shearing, pressing, coining, casting, boring, broaching and calibrating through plastic deformation.

3. The process as defined in claim 1 wherein said coating through anodic oxidation is conducted through electrolytic treatment in a bath having a determined acid¬ ity while regulating the composition of the bath, the tem¬ perature of the bath, the electric current passing through the bath and the duration of the electrolytic treatment to form said layer of aluminum oxide.

4. The process as defined in claim 3 wherein said lapping operation removes a portion of said layer of alu¬ minum oxide in accordance with the level of precision, planarity and roughness of said aluminum oxide layer re¬ sulting from the anodic oxidation.

5. The process as defined in claim 4 wherein said impregnation operation is conducted through immersing said control member in an impregnating fluid.

6. The process as defined in claim 4 wherein said impregnation operation is conducted through physical depo¬ sition of an impregnating substance directly into the pores of said aluminum oxide layer.

7. The process as defined in claim 4 wherein said impregnation operation is conducted through chemical depo¬ sition of an impregnating substance directly into the pores of said aluminum oxide layer.

8. The process as defined in claim 1 wherein said main body is lapped to form a finished surface prior to coating said main body through anodic oxidation.

9. A process for the manufacture of hard surfaced fluid control members for faucets comprising the steps of: forming the main body of said control member for fau¬ cets of an aluminum-based metal; coating said main body through anodic oxidation with a layer of aluminum oxide; impregnating the pores of said aluminum oxide layer with a filler material; and lapping said layer of aluminum oxide to form a fin¬ ished surface adapted to function as a seal.

10. The process as defined in claim 9 wherein said main body is formed by a metallurgical process selected from the group consisting of shearing, pressing, coining, casting, boring, broaching and calibrating through plastic deformation.

11. The process as defined in claim 9 wherein said coating through anodic oxidation is conducted through electrolytic treatment in a bath having a determined acid¬ ity while regulating the composition of the bath, the tem¬ perature of the bath, the electric current passing through the bath and the duration of the electrolytic treatment to form said layer of aluminum oxide.

12. The process as defined in claim 11 wherein said lapping operation removes a portion of said layer of alu¬ minum oxide in accordance with the level of precision, planarity and roughness of said aluminum oxide layer re¬ sulting from the anodic oxidation.

13. The process as defined in claim 12 wherein said impregnation operation is conducted through immersing said control member in an impregnating fluid.

.

14. The process as defined in claim 12 wherein said impregnation generation is conducted through physical dep¬ osition of an impregnating substance directly into the pores of said aluminum oxide layer.

15. The process as defined in claim 12 wherein said impregnation operation is conducted through chemical depo¬ sition of an impregnating substance directly into the pores of said aluminum oxide layer.

16. A control member for use in faucets to control the flow of fluid in the faucet, said control member com¬ prising: a main body formed of an aluminum-based metal; a coating layer of aluminum oxide applied to said main body, said aluminum oxide layer having a smooth fin¬ ish and a plurality of pores; and an impregnating substance impregnated within said pores of said aluminum oxide layer.

17. The control member as defined in claim 16 where¬ in said aluminum oxide layer is applied to said main body through anodic oxidation.

18. The control member as defined in claim 17 where¬ in said impregnating substance is selected from the group consisting of a synthetic resin, graphite, molybdenum sulfide and silicon.