Abstract:
A poppet seat for air regulating devices, such as underwater diving equipment, includes a metal or plastic substrate around and through which synthetic or rubber seat material is molded. In its preferred form, this seat material surrounds the sides of the substrate and fills holes therein as well as an annular v-groove formed in the periphery of the substrate to further enhance the mechanical bond between the substrate and seat material.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     If Any: None. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the art of poppet seats and more particularly to poppet seats useful in air regulating devices. In its most preferred embodiment, the present invention relates to an improved poppet seat in which synthetic or natural rubber seat material is molded around and through an annular carrier. The invention also relates to a method for making a poppet seat of this type. 
     2. Description of the Prior Art 
     In the field of air regulating devices, such as those used in underwater diving equipment (more commonly known as scuba equipment) breathable air is provided to the diver from a pressurized air source, e.g. a compressed air cylinder, a surface supply hose, etc. 
     In most equipment a primary regulator is employed to reduce the air pressure available to the diver from the pressurized source, such as a pressurized air tank, and a demand regulator functions to supply air in accordance with the diver&#39;s breathing pattern. In current demand regulators, poppet seats have been commonly manufactured by providing a carrier base made out of plastic or metal material and having a groove about its center. Pliable seat material has been added to the groove and has been held in place by friction and/or by adhesive bonding. In one prior art device, such seats were exposed to pressures in the range of 120-150 pounds/in 2  and made spring loaded contact with a coned orifice member to provide a complete seat of the pressure. Such poppet seats are subjected to widely varying environmental conditions and cyclic use since each time a breath is taken, a spring is relieved thereby allowing movement of the coned orifice member toward and away from the seal and permitting the bypass of breathable air to the scuba diver. 
     Such poppets have proved to be highly effective over extended periods of time, but several design aspects of the current system make it possible for small leakage to occur. For example, the coned orifice can become damaged or the seating surface itself may be contaminated or deformed. These occurrences are especially likely in situations where the regulator is not maintained properly, e.g. if it is not reused as recommended by most manufacturers. Leakage could also occur if the seat material becomes delaminated from the substrate carrier base, as could happen for example if the adhesive or frictional forces became weakened. If any of these occurrences would take place while the diver was below water, normal emergency procedures, such as the use of a back-up regulator, would be employed to allow a divers safe return to the surface. Repair of this regulator would then be required. 
     While the first two problems mentioned above may be readily cured by proper maintenance, the later problem is less easy to observe, as it can occur over time. An improvement in design would be desirable to make sure the air supply is not bypassed due to inappropriate separation of the seat material from the carrier component. 
     SUMMARY OF THE INVENTION 
     The present invention features a seat for use in air regulating devices, such as second stage regulators in diving equipment, in which pliable material is applied through holes in the carrier to provide a mechanical securing of the seat material to its substrate. In accordance with another feature, the present invention employs such mechanical attachment in combination with chemical bonding to increase, even further, the adherence of the seat material to its substrate. 
     More specifically, the present invention features a technique for encapsulating a substrate base and anchoring seat material therethrough by means of through-hole molding using holes which are geometrically reversed when compared to the direction from which delamination forces would be most likely to occur. 
     Yet another feature of the present invention is to provide an encapsulated substrate, wherein the encapsulating seat material forms a seating member that also flows into a v-groove surrounding the periphery of the substrate to enhance attachment thereto. In still another modification of the later feature, the v-groove intersects a plurality of through holes to further enhance the security of the seat and substrate. 
     The invention also features a method for manufacturing a valve seat of the type including an annular base and an elastomeric seating material affixed to the base. The method includes the steps of forming an annular groove in the base and securing the seating material to the base such that the seating material contacts at least a portion of the groove generally in opposing relation with respect to an upper surface of the base. 
     How these and other features of the present invention are accomplished will be described in the following detailed description of the preferred embodiment, taken in conjunction with the drawings. Generally, however, they are accomplished by using a synthetic or natural rubber seat material and molding it with a substrate which is preferably of annular form. In the most preferred embodiment, the substrate includes a v-groove around its periphery and a plurality of holes so that the molding material passes through the holes and around the v-groove, most preferably encapsulating the entire periphery of the carrier. In the most preferred embodiment, the holes of the substrate are geometrically reversed to increase the seats ability to withstand any delamination forces. Other ways in which the objects of the invention are accomplished will become apparent from the following detailed description after it is read and understood by those knowledgeable in the art. Such other ways are also deemed to fall within the scope of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a bottom plan view of the poppet seat forming the most preferred embodiment of the present invention; 
     FIG. 2 is a side elevation showing the seat material lip extending from the upper surface of the seat; and 
     FIG. 3 is a cross section taken along the line  3 — 3  of FIG. 1 showing the location of the molding material and the reversed drilled holes and v-groove around the perimeter of the substrate. 
     In the various FIGURES like reference numerals are used to indicated like components. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Before proceeding to the detailed description of the preferred embodiment, several general comments should be made about the applicability and the scope of the present invention. First, with regard to the materials to be employed, the carrier or substrate material is most commonly prepared from a metal such as brass or stainless steel, although plastics could also be employed. As to the seat material itself, synthetic or natural rubber materials are preferred, the most typical being silicone rubber which has been used heretofore in preparing such seats for air control devices. A preferred seat material in the present invention is silicon rubber, such as Silastic LCS 755 silicon rubber, manufactured by Dow Corning. 
     As to the use of the seat described in this section of the specification, it could be employed in a number of devices other than that mentioned in the background section hereof. For example, the article shown in the drawings could be used in a wide variety of air or other fluid control devices wherein it is desired to have structural rigidity and mechanical adherence of a pliable seat material to a substrate. This should be kept in mind as the balance of the specification is read, even though demand regulator poppet seats are mentioned and shown. One familiar with air control devices could readily adapt the teachings of the present invention to other seat design, taking into account such factors as diameter, thickness, applicable durometer, environmental conditions and the like. Furthermore, one could refer to the instruction manuals, engineering bulletins and maintenance guides for such regulators as the Scubapro Models D400, D350, D300 and AIRI to learn more about such poppet seats and their interaction with other control device components. Copies of Scubapro Engineering Bulletin Nos. 237 and 238 are submitted with this specification for that purpose. 
     Proceeding next to a brief description of the prior art, prior art molded seats have been made using annular brass inserts or substrates, much like a washer, having a central through opening and an annular groove in one surface thereof. Rubber was added by a molding process to the groove to provide a seat for the coned orifice mentioned above. 
     In the present invention, molded rubber in a groove is replaced by rubber which is molded with the insert so that it, in the most preferred embodiment, surrounds the sides and fills various through holes to be described in detail hereafter. A molded seat  10  according to the present invention is show in bottom view in FIG.  1 . The molding material  11  encases the periphery  12  of a substrate  14 , and the rubber passes through holes  17 - 20  as shown at  22 - 25 . The central opening of the substrate is shown at  27 . 
     A side view of the molded seat is shown in FIG. 2 when a lip  30  is shown extending from the upper surface  32 . The configuration of the lip will become more apparent as the explanation continues with a description of FIG.  3 . 
     FIG. 3 is a sectional view showing that the substrate in the most preferred embodiment, includes a v-groove  33  surrounding its periphery, while a recess  35  extends around its upper surface. FIG. 3 also illustrates that through holes  17 - 20  are provided, as shown particularly at the bottom of this FIGURE. For hole  19 , reverse drilling has occurred so that the hole has a smallest diameter  36  near its upper surface  32  and a larger diameter portion  38  near the bottom surface. 
     From this description and from FIG. 3 it is evident that the holes  17 - 20  intersect the bottom of the v-grooves  33  so that rubber may flow from the holes  17 - 20  into the v-groove  33  or vice versa. Note that while the rubber does not extend beyond the bottom surface  40  of the brass substrate  14 , it does flow into portion  38  of the holes  17 - 20  to resist any delamination forces which may exist. 
     In addition to the mechanical forces used to hold the molded seat material to the substrate, chemical bonding aids may also be employed. In the most preferred embodiment of the invention, chemical bonding is provided by using a bonding agent, and preferably methanol based agents, such as Chemlock Adhesive No. Y1540, available from Lord Chemical Products. 
     While the preferred embodiment shows two different techniques for increasing the mechanical bonding of the seat material to the insert, each of the techniques, the through holes  17 - 20  and the v-groove  33 , could be employed separately to enhance performance when compared to the prior art devices described above. Optimum results would be obtained by using both, together with a chemical bonding agent. 
     While the present invention has been described and illustrated in connection with a single preferred embodiment, it is not to be limited thereby but is to be limited solely by the claims which follow.