Patent Description:
Solenoid valve systems for controlling flow of hydraulic or pneumatic fluid have been used in automated manufacturing equipment, production lines and numerous industrial applications. A plurality of solenoid valve housings, often referred to as manifold valve housings, manifold valve bodies, valve housings or valve bodies, typically are mounted on a manifold having a plurality of passages for supplying fluid to the valves and providing passages to various outlet ports of each valve. Each solenoid of each valve housing typically is connected to an electronic system that controls operation of the several solenoids and valves. A typical manifold may contain many valve housings. The parts in a typical valve housing include gaskets, sleeves, mounting bolts and fasteners for attachment to other valve housings.

In the past, multiple valve housings were often mounted on a single manifold housing. Such arrangement is known from, e.g., document <CIT>. As shown in <FIG> and <FIG> of this document, each valve housing, when viewed in plan view, has through holes at diametrically opposite corners to accommodate a fastener for attachment to the manifold housing below. The main disadvantage of the single manifold housing was that it limited the number of valve housings that can be assembled together, i.e. there was no adaptability to make the manifold longer to house more valve housings.

As a consequence, modular manifolds were developed. This modular manifold includes manifold modules mounted adjacent one another. The number of manifold modules used was adjustable up to a desired number. Each manifold module has a valve housing mounted thereon with the appropriate fasteners and seals.

The valve element used in these solenoid valve housings is typically a valve spool. Valve spools for pneumatic valves typically function as an air bearing. The valve spool made from hardened 440C stainless steel is slidably received in the valve hole of the sleeve. The valve spool is finished to slidably fit within a valve hole and to slide virtually frictionless by floating on a thin air cushion as it reciprocates within the valve hole. The precise fit of the valve spool in the valve holes provides for a valve with an acceptably low leakage rate. The air cushion also provides for a long lasting, durable, and fast acting valve.

The valve housing is commonly made from aluminum. Aluminum is often used because it can be easily cast. Hardened 440C stainless is less amenable for casting and would require expensive machining. As a consequence of the harder metal of the valve spool, the valve housing up to now has not been able to directly receive the valve spool therein, but needs an intermediate member, often referred to as a sleeve. If the valve spool is received directly in the valve hole of the valve body, galling takes place which degrades the function of the valve. Furthermore, any contaminates within the valve housing can scratch the wall surface of the valve hole upon sliding of the valve spool within the valve hole which also degrades the function of the valve.

The sleeve prevents or reduces galling and scratching. The sleeve is made of hardened 440C stainless steel and is fitted into the valve hole with elastomer seals separating the different galleries. The sleeve needs to be properly positioned for appropriate alignment of the respective ports of the sleeve and the valve housing to assure that the valve spool properly works. The sleeve has gaskets, O-rings or other seals seated on its exterior wall properly positioned to assure that the different ports in the valve housing are selectively sealed from one another about the perimeter of the sleeve so that the valve properly functions. The hardened 440C stainless steel prevents galling and scratching between the sleeve and valve spool.

The valve housing and the sleeve both need to have a certain wall thickness to maintain structural integrity. This requirement for structural integrity adds width to each valve housing. This added width is more noticeable, i.e. accentuated for smaller more compact valve housings.

Other parts, namely fasteners, for example nuts and bolts are commonly used to assembly the individual valve housings together. Separate adapters in the form of fittings are also mounted onto each housing to be connected to various input and output lines. Fasteners are also needed to mount the valve housing onto the manifold module. The fasteners, sleeve, and seals between the valve spool, sleeve, valve housings, and manifold modules, however add complexity and cost in machining and assembly to the finished valve unit.

Document <CIT> discloses a hydraulic control block including a plurality of valve segments lying on top of one another and detachably connected to one another. A control piston arranged in each valve segment is configured to control inflow of hydraulic oil from a pressure source to a load or discharge of hydraulic oil from a tank. Each control piston is hydraulically operable by at least one pilot valve and each pilot valve is electromagnetically operable. A housing sealed off from surroundings is fixed on each valve segment, and one or several pilot valves assigned to each relevant valve segment are mounted in the housing, wherein the pilot valves assigned to each valve segment are attached directly to the valve segments. A tank line is formed in the valve segments and leads to the tank for the hydraulic oil in which a preload pressure corresponding to the relevant ambient pressure prevails. A channel formed in the respective valve segment leads from the tank line to the interior of the assigned housing so that the pressure of the tank also prevails in the interior of the housing.

Further, document <CIT> discloses a valve arrangement comprising valve units in a row that form a series of valves, within which the valve units are combined to form a package. The free end face of the first and last valve unit of the valve row is fitted with a disc-shaped end module. Valve row penetrating tie rods are anchored in the end modules, which hold the end modules and valve row firmly together to form a package. <FIG> of this document shows openings which pass through a respective valve unit in the direction of arrangement and through which the tie rods not shown pass. According to this prior art, each valve unit has a main body, which forms the housing of a main valve. In the main body there is a receiving chamber, running parallel to the longitudinal axis, which receives a valve slide that is designed as a piston. A supply channel opens into the receiving chamber, through which fluid pressure medium, in particular compressed air, is supplied. In addition, two discharge channels open into the receiving chamber, through which used pressure medium is discharged and, in the case of compressed air, vented.

Finally, another modular valve arrangement, comprising individual valves which can be joined together via fastening elements in the form of a dovetail guide, is known from document <CIT>, wherein in the joined state of the valve arrangement there is at least one pressure medium line running through the entire valve arrangement.

What is needed is a monolithic, i.e. integrally formed combination manifold and valve housing with a reduced number of parts needed for it to be operational and connectable to other combination manifold and valve housings. For example, what is needed is a valve spool assembly that directly slidably mounts a valve spool without the intermediate sleeve or seal members. What is also needed is a monolithic module or modular unit that includes both a manifold section and a valve section. The monolithic housing slidably mounts a valve spool and provides internal passages to internal cross passages that extend laterally across the manifold section. What is also needed is a combination manifold and valve housing that is able to be simply mounted to an adjacent manifold and valve housing preferably without the need for separate fasteners. What is also desirable is a combination manifold and valve housing preferably made of hardened 440C stainless steel that slidably receives a valve spool. What is also desired is a combination manifold and valve housing that is made by additive manufacturing to provide integrally formed inlet and outlet fittings and made from 440C stainless steel. What is also desired is a valve housing made by additive manufacturing with a hardened 440C stainless steel section about an internal hole that slidably mounts a valve spool.

The above objects are solved by the features specified in claim <NUM>. Advantageous and appropriate developments of the invention form the subject matter of claims <NUM> to <NUM>.

According to the present invention, a valve manifold bank formed by a plurality of housings is provided, each housing comprising: a first lateral side having a set of ribs that are angled from each other along a vertical axis, wherein the term vertical relates to the directional orientation between a top wall and a bottom wall of housings; and a second lateral side having a set of grooves that are angled from each other along said vertical axis and interlockable with the set of ribs on an adjacent housing; each of the ribs having distal edges facing away from each other and extending at an included angle to form a wedge; and each of the grooves having distal edges facing toward each other and forming a wedge shaped cavity therebetween; wherein the wedge is slidably engageable with a wedge shaped cavity of the adjacent housing until the ribs lock within the grooves to frictionally lock the housings together to form the valve manifold bank.

In one preferred embodiment, a raised lateral surface of each of the housings is formed between two spaced ribs and canted to form a wedge; the wedge having its greatest thickness in proximity to or at one of the bottom and top walls of each of the housings and tapered to the other of the bottom and top walls of each of the housings; wherein a recessed lateral surface of each of the housings is formed between two facing grooves and canted to form a wedged shaped cavity; the wedge shaped cavity having its greatest depth at one of the bottom and top walls of each of the housings and being tapered toward the other of the bottom and top walls of each of the housings; and wherein the raised lateral surface of each of the housings is slideably engageable to a recessed lateral surface of the adjacent housing, and is able to compress a sealing gasket positioned about a fluid passage interposed between the respective recessed and raised lateral surfaces of the housings.

Preferably, each of the ribs is canted inward toward each other at an included angle of less than <NUM>° to form a self locking taper; and each of the grooves is canted toward each other at a same respective angle of less than <NUM>° to form a self locking taper.

In one preferred embodiment, each of the housings is a combination modular housing having a valve section and a manifold section integrally formed for the valve manifold bank, the combination modular housing comprising: at least one fluid passage extending from the first lateral side to the second lateral side to be alignable with at least one fluid passage of an adjacent combination modular housing; the valve section having a cavity sized to receive a valve therein.

In this embodiment, preferably, the cavity in the valve section is a hole therein for slidably mounting a valve spool directly therein with no sleeves or seals interposed therebetween.

Finally, preferably, the combination modular housing is made from 440C stainless steel.

Reference now is made to the accompanying drawings in which:.

Referring now to <FIG>, a manifold bank <NUM> includes a series of monolithic combination modular units, each referred to as a housing <NUM>, connected to each other in facing engagement. Each housing <NUM> includes an integrally formed lower manifold section <NUM>, and an upper valve section <NUM>. The housing <NUM> is made by additive manufacturing to integrally form the manifold section <NUM> with the valve section <NUM>, i.e. the housing is monolithic. A solenoid pilot valve <NUM> is mounted thereon for actuating a valve spool <NUM> slidably movable in the valve section <NUM>. The housing <NUM> and valve spool <NUM> are made from a hardened stainless steel, for example hardened 440C stainless steel. The valve section <NUM> illustrated in <FIG> represents a miniature valve e.g. less than a <NUM> in width valve housing. Connecting grooves <NUM> and ribs <NUM> are on respective lateral side walls <NUM> and <NUM> to connect adjacent housings <NUM>.

As more clearly shown in <FIG> and <FIG>, the valve section <NUM> has a valve hole <NUM> therein that slidably receives the valve spool <NUM>. The valve hole <NUM>, defined by its wall <NUM>, is circular in cross section as shown in <FIG> and is generally cylindrical in shape as illustrated in <FIG>. As shown in <FIG>, and <FIG>, three lateral passages <NUM>, <NUM> and <NUM> in the manifold section extend laterally through each housing <NUM> from one lateral side wall <NUM> to the other lateral side wall <NUM> to form passages through the manifold bank <NUM> as a whole.

There are three internal paths <NUM>, <NUM> and <NUM> in fluid communication at axially spaced points along the valve hole <NUM> and intersect the valve hole <NUM> substantially transversely. The internal paths <NUM>, <NUM>, and <NUM> are in fluid communication with the three lateral passages <NUM>, <NUM> and <NUM> and intersect them transversely. The valve hole <NUM> is also substantially transverse to the lateral passages <NUM>, <NUM>, and <NUM>. Two external ports <NUM> and <NUM> extend upwardly from the valve hole <NUM> and are each fitted with a tube connector or fitting <NUM> at top wall <NUM>. The fitting <NUM> may also be integrally formed with the housing <NUM>.

The valve spool <NUM>, as illustrated, is biased in one direction by a coil spring <NUM> and is movable in the opposing direction as a function of fluid pressure applied to the opposing end of the valve spool. The spring <NUM> may be replaced with a dual action solenoid valve. The fluid pressure is controlled by the solenoid valve <NUM> mounted at an associated end of the valve section <NUM>.

The valve spool <NUM> has three lands <NUM>, <NUM>, and <NUM>, with land <NUM> interposed between lands <NUM> and <NUM>. In one position of the valve spool, port <NUM> is in communication with port <NUM> while port <NUM> is in communication with exhaust port <NUM>. In another position of the valve spool, port <NUM> is in communication with path <NUM> while port <NUM> is in communication with exhaust path <NUM>. The illustrated port arrangement is only one example of numerous possible port and land arrangements for the valve depending on the application.

The lands <NUM>, <NUM> and <NUM> of valve spool <NUM> are sized both to slide freely within valve hole <NUM> and also to control fluid flow between paths <NUM>, <NUM>, and <NUM> and appropriate inlet port <NUM> to appropriate exit ports <NUM> and <NUM>. The size of the valve spool provides an acceptably low leakage rate between the lands and the wall <NUM> of the valve hole <NUM>. The lands are directly opposed and adjacent to the wall <NUM> without any intervening sleeve or gasket. To provide for the appropriate air bearing function between the valve spool <NUM> and housing, the valve spool <NUM> is lapped until it is of proper size and the valve hole <NUM> is also finished to the appropriate manufacturing tolerances.

In operation, the valve spool <NUM> slides between its two positions to selectively communicate valve ports <NUM> and <NUM> with inlet path <NUM> and exhaust paths <NUM> and <NUM>. As best shown in <FIG>, the thinnest section of wall section <NUM> of the valve section <NUM> is along a horizontal mid-line. By eliminating any intermediate sleeve, the housing <NUM> can be thinner compared to valve housings for sleeved valve spools of comparable flow ratings while still providing the same structural integrity at wall section <NUM>.

By having both the valve section <NUM> (at least layer <NUM> thereof) and the valve spool <NUM> made from hardened 440C stainless steel, the valve spool can slidably mount directly in a valve hole of the valve section <NUM> without the need of an intermediary element, e.g., a sleeve. The hardened stainless steel is resistant to both galling and scratches from impurities to maintain a durable valve. While the above illustrated valve spool can be less than <NUM> in width, the sleeveless valve spool is not confined to a specific size.

Another alternate embodiment of a sleeveless valve spool is shown in <FIG> which illustrate a separate valve housing assembly <NUM> with valve section <NUM>, valve hole <NUM> and valve spool <NUM>. Comparable parts are shown with the same numerals as the previously described embodiment. The paths <NUM>, <NUM> and <NUM> are now external ports and extend downwardly to the bottom wall <NUM> of the valve section <NUM> to be conventionally mounted to a separate modular manifold module (not shown) or other fittings.

The four-way two position valves are shown as examples. Other types of valve spools other than two position four-way valves are also possible for many different applications. While a spring loaded return valve is shown, a direct solenoid or a dual solenoid pilot actuated valve assembly may be provided where an actuator solenoid <NUM> or solenoid pilot is positioned at each end of the valve section <NUM>. As with the first embodiment, this valve section <NUM> may be formed by additive manufacturing with the valve hole <NUM> being finished to proper specifications.

The housing <NUM> and valve section <NUM> are made from 440C stainless steel and preferably need to be painted or undergo a passivation process to remove the free iron. A chromium oxide layer can be a preferred coating. This coating provides for durability and integrity of the surface of the valve section <NUM>.

Referring now to <FIG>, additional fasteners may also be eliminated by use of integrally formed connectors, e.g. a wedge and fastenerless self locking connection between the plurality of housings <NUM>. The connectors include grooves <NUM> and complementarily shaped ribs <NUM> that connect two adjacent housings <NUM> together. Each groove <NUM> on front lateral side wall <NUM> faces the other and is tapered from the bottom wall <NUM> to the top wall <NUM>. As shown in the drawings, the bottom wall <NUM> and the top wall <NUM>, as labeled, are shown in the respective top and bottom position but the housing <NUM> can be positioned in any orientation when installed as the application dictates. The term "vertical" relates to the directional orientation between the top wall <NUM> and bottom wall <NUM> and is not dictated by orientation to the earth. Each groove <NUM> and rib <NUM> has its respective surfaces from an approximately <NUM>° angle as shown in <FIG> for the preferred embodiment. Other angles are possible as long as they provide a suitable engagement between the ribs and grooves as described below.

A recessed surface <NUM> is formed between the two facing grooves <NUM>. The recessed surface <NUM> has a slight recess cant for example, <NUM>° from the remainder of the wall <NUM>. The extending lateral passages <NUM>, <NUM> and <NUM> are positioned near the bottom wall <NUM> at the deeper section of recessed surface <NUM>. Complementarily shaped ribs <NUM> extend from lateral wall <NUM> and are tapered from the bottom wall <NUM> to the top wall <NUM>. A complementary canted male surface section <NUM>, i.e. raised surface of lateral wall <NUM> is formed between the two spaced ribs <NUM>. The lateral passages <NUM>, <NUM> and <NUM> extend through the bottom thicker section of canted male surface section <NUM>. The cant of the recessed surface <NUM> and the male surface section <NUM> are complementary and can vary depending on the application. For example, if thicker gaskets <NUM> are used, the cant may be greater to provide greater clearance as needed. On the other hand, if flow rates require a larger diameter valve hole <NUM>, then a lesser cant is desired to provide more usable housing width for providing sufficient structural integrity at wall section <NUM>.

As shown in <FIG>, a gasket receiving area <NUM> surrounds the lateral passages <NUM>, <NUM> and <NUM>. The gasket <NUM> is made from commercially available elastomeric material that is suitable for sealing the lateral passages <NUM>, <NUM> and <NUM> from each other and the ambient exterior and seals between the recessed surface <NUM> and raised surface <NUM> of an adjacent housing.

The grooves <NUM> and complementary ribs <NUM> are also tilted inward toward each other from the bottom wall <NUM> to the top wall <NUM>. The degree of tilt is slight enough to form a self locking connection when wedged together as described below. For example, the tilt of each groove <NUM> and rib <NUM> forms an included angle of less than <NUM>° between the two opposing grooves <NUM> and the two opposite ribs <NUM>. This included angle is measured along the canted planes of surfaces <NUM> and <NUM> as shown by line <NUM> illustrated in <FIG> and not along the vertical line <NUM>, i.e. not along the plane of <FIG> and <FIG>. It has been found that with an included angle of less than <NUM>°, the grooves <NUM> and ribs <NUM> can self lock by friction when their surfaces are wedged together.

As shown in <FIG>, assembly of the modular housings <NUM> to form the manifold bank is simplified without the use of fasteners. One housing <NUM> as shown in <FIG> is shown in the partially installed position and is moved downwardly with respect to the other housings <NUM>. The other two housings <NUM> are shown in a fully installed position. In this partially installed position, it becomes clear that the partially installed housing <NUM> has its canted recessed wedge surface <NUM> spaced from the canted raised surface <NUM> of an adjacent housing <NUM> to provide clearance to pass by the gasket <NUM> seated in gasket seating area <NUM>. As the housing <NUM> is moved downwardly, the recessed surface area <NUM> moves toward the raised canted surface <NUM> until it abuts and compresses against the gaskets <NUM> between the two adjacent housings as shown for the other two fully installed housings <NUM> to provide a seal. Simultaneously, the ribs <NUM> and grooves <NUM> engage each other along their entire surface and are wedged together to provide a self locking tight joint that requires a substantial force to become loosened.

It should be noted that the taper can extend from the top wall <NUM> to the bottom wall <NUM> as shown in <FIG> if lesser clearance is needed for the gasket <NUM> about gasket area <NUM>.

It should be understood that the canted raised wedge surface <NUM>, canted recessed surface <NUM>, ribs <NUM>, and grooves <NUM> have further applications than only to a combination housing <NUM>. It can be applied to separate valve section <NUM> as a separate independent housing <NUM> like the one illustrated in <FIG> or can apply to separate manifold bodies. The interlocking connectors can also apply to mounting solenoid pilot valve spring housings and other individual valve related components.

Another embodiment is shown in <FIG>. In this embodiment, each housing <NUM> can be independently removed and installed without disturbing the remaining bank of housings <NUM>. The grooves <NUM> and complementarily shaped ribs <NUM> connect two adjacent housings <NUM> together. Each groove <NUM> on front lateral side wall <NUM> faces the other and vertically extends from the bottom wall <NUM> to the top wall <NUM>. Each rib <NUM> extends from lateral wall <NUM> and similarly vertically extends from the bottom wall <NUM> to the top wall <NUM>.

A vertically oriented recessed surface <NUM> is formed between the two facing grooves <NUM>. The complementarily shaped ribs <NUM> extend from lateral wall <NUM>. A raised male section <NUM> of lateral wall <NUM> is formed between the two spaced ribs <NUM>. The raised male section <NUM> is also vertically oriented. The bottom and top edges of the raised wall section <NUM> have an inviting angle section <NUM> that can be canted backwards at a gentle angle, i.e. less than <NUM>°. A gentle inclination of <NUM>°-<NUM>° is foreseen to work. Similar inviting angle sections <NUM> surround port exits <NUM>, <NUM> and <NUM> on the male raised section <NUM>. These inviting angle sections <NUM> and <NUM> assist in promoting the male section <NUM> to slide over the gasket <NUM> so as to not shear the gasket <NUM>.

Each housing <NUM> has two holes <NUM> that laterally pass therethrough to receive a respective alignment pin <NUM>. When fully installed the ribs <NUM> and grooves <NUM> prevent the housings <NUM> from transversely moving relative to each other and the alignment pins <NUM> prevent the housings <NUM> from vertically moving with respect to each other as more clearly shown in <FIG>.

As shown in <FIG>, assembly of the housings <NUM> to form the manifold bank is simplified without the use of threaded fasteners. One housing <NUM> is shown in the partially installed position. The housing <NUM> is moved upwardly or downwardly with respect to the other housings <NUM>. The other housings <NUM> are shown in a fully installed position. In this partially installed position, it becomes clear that the partially installed housing <NUM> is merely slid downwardly. The elastomeric gasket <NUM> slidingly and sealingly abuts against the raised section <NUM>. Once in the vertically correct position, an alignment pin <NUM> is inserted in each of the holes <NUM>. The housing <NUM> also has the ability to slide upwardly to the installed position from below.

If a housing <NUM> needs to be replaced, the alignment pins <NUM> are merely withdrawn, the manifold housing <NUM> is pulled up as shown in <FIG>, removed, and replaced with another. The alignment pins <NUM> are then reinserted. In this fashion, a single manifold housing <NUM> can be replaced at any position along the manifold bank without disturbing the remaining housings in the bank.

Many advantages result from the housing <NUM> being produced by additive manufacturing. The term additive manufacturing, as used herein, is a general industry term defined by ASTM F2792 and refers to all types of processes that build up a component by depositing material as opposed to prior conventional production techniques of removing material. Other synonymous terms, for example, additive fabrication, additive processes, additive techniques, additive layer manufacturing, layer manufacturing, rapid prototyping and freedom fabrication are also commonly used. The additive manufacturing may include, but not limited to 3D printing, stereolithography, selective laser sintering, sintered metal forming, fused deposition modeling and solid ground curing.

Additive manufacturing provides for the integral formation of a combination manifold section and valve section. This integral formation of a combination manifold section and valve section reduces the number of separate ports dramatically. It eliminates the need for fasteners and seals for mounting when a conventional valve housing is mounted to a separate manifold housing. Furthermore, additive manufacturing of the manifold housing can expeditiously form all of the manifold exhaust passages <NUM> and <NUM>, supply passage <NUM>, internal paths <NUM>, <NUM> and <NUM> and ports <NUM> and <NUM>, valve hole <NUM>, as well as solenoid air supply passage <NUM> which leads from supply passage to a connector port <NUM> for the solenoid pilot valve <NUM> without the use of drilling or boring. Particularly noted are the paths <NUM>, <NUM> and <NUM>. Which paths, as shown in the figures, are internal and are not economically feasible to drill or otherwise, machine out of the monolithic housing. As such, a monolithic housing was not economically feasible to manufacture with these internal paths with the conventional manufacturing methods. The additive manufacturing also eliminates the need for plugs in access ports that were previously needed to machine the internal paths.

The additive manufacturing also makes a blended metal assembly achievable. For example, 440C stainless steel material can be provided about the valve hole as illustrated by section or layer <NUM> and the integrally formed remainder of the valve housing and manifold section of the housing <NUM> can be made from less expensive and/or softer material, e.g. <NUM> surgical steel or low carbon steel. Alternatively, the remainder may be a harder material, e.g. tungsten. Additive manufacturing eliminates the need for separate slip-in fittings, barbs, and jets because they can all be integrally formed by additive manufacturing as illustrated with fitting <NUM> formed about ports <NUM> and <NUM> shown in <FIG> while still being cost effective. The paths <NUM>, <NUM> and <NUM> may also have integrally formed fittings.

Additive manufacturing expeditiously can reduce expense and weight by forming supporting webs and ribs with hollow cavities where metal is not required. Thus, less material is used compared to the use of solid bar stock as a starting material.

In this fashion, a monolithic manifold housing made by additive manufacturing has a manifold section and valve housing that is sleeveless and can be mounted to other housings without fasteners. A manifold bank having a plurality of these housings connected together can be simply assembled with a significant reduction in parts.

Claim 1:
A valve manifold bank (<NUM>) formed by a plurality of housings (<NUM>), each housing (<NUM>) comprising:
a first lateral side (<NUM>) having a set of ribs (<NUM>) that are angled from each other along a vertical axis, wherein the term vertical relates to the directional orientation between a top wall (<NUM>) and a bottom wall (<NUM>) of each of said housings (<NUM>); and
a second lateral side (<NUM>) having a set of grooves (<NUM>) that are angled from each other along said vertical axis and interlockable with said set of ribs (<NUM>) on an adjacent housing (<NUM>);
each of said ribs (<NUM>) having distal edges facing away from each other and extending at an included angle to form a wedge; and
each of said grooves (<NUM>) having distal edges facing toward each other and forming a wedge shaped cavity therebetween;
wherein said wedge is slidably engageable with a wedge shaped cavity of said adjacent housing (<NUM>) until said ribs (<NUM>) lock within said grooves (<NUM>) to frictionally lock said housings (<NUM>) together to form said valve manifold bank (<NUM>).