Modular Hydraulic System

Abstract

A modular hydraulic system is provided. Each of the components of the system is contained in a generally rectangular housing unit formed of a plurality of opposed pairs of walls including end walls, front and rear walls, and top and bottom walls. At least one passageway extends into each unit between the component and at least one of the walls of that unit. One of the walls of each opposed pair is adapted to be coupled to the other wall of the corresponding pair of another unit of the system with the walls in surface-to-surface contact and the passageways terminating on the abutting walls in aligned registry. The units are coupled to one another by means of a plurality of fasteners with each fastener passing partially through each of the housings to be coupled.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a multicomponent modular hydraulic system utilizing housing units for the various components which may readily be coupled to other similar units. The components may be in the form of directional valves, output controls, manifold and return lines, etc., so that by suitably connecting units having the necessary components a wide variety of functions may be obtained with the system.

The principle object of the present invention is to provide a hydraulic system wherein the various components of the system are each individually contained in housing units which may readily be connected to other similar units bearing other components in such a manner that the coupling of the housings to one another also serves to operatively connect the components.

A further object is to provide such a system which is capable of withstanding relatively high pressures and wherein the units are readily interchangeable and replaceable.

In the foregoing and following description the term "hydraulic" is meant to relate to all types of fluid systems including those systems utilizing water, air, oil, or other liquids or gases.

SUMMARY OF THE INVENTION

The above and other beneficial objects and advantages are obtained in accordance with the present invention by providing a hydraulic system comprising a plurality of components, which may be in the form of tank and return lines, directional valves, reducing valves, etc., each of the components being contained within a housing unit. The units are each generally rectangular in shape and formed of a plurality of opposed pairs of walls including end walls, front and rear walls, and top and bottom walls. At least one passageway extends into the interior of each unit in communication with the component contained therein and terminates on at least one of the walls. At least one of the opposed pairs of walls includes a first wall having surfaces adapted to engage in surface-to-surface contact, the second wall of the corresponding pair of another unit and a second wall adapted to similarly engage the first wall of the corresponding pair of another unit. Fastening means are provided for coupling the units to one another with the corresponding passageways terminating on abutting surfaces in aligned registry. The fastening means extend only partially through each of the units being coupled.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is an exploded perspective view illustrating the modular hydraulic system in accordance with the present invention, this view shows the front, top and one side of the units along with several associated units shown in phantom;

FIG. 2 is a view similar to that of FIG. 1 showing the rear, bottom and other side of the units;

FIG. 3 is a perspective view illustrating a plurality of such units in vertical array design to provide a particular hydraulic control function;

FIG. 4 is a sectional view taken along reference lines 4--4 of FIG. 3 in the direction indicated by the arrows;

FIG. 5 is a schematic representation of a typical hydraulic circuit utilizing conventional USASI symbols;

FIGS. 6 is a fragmentary front elevational view of the circuit of FIG. 5 constructed utilizing the modular units of the present invention;

FIG. 7 is a fragmentary plan view illustrating alternate means for coupling the component units to one another which is particularly well adapted to withstand relatively high pressures;

FIG. 8 is a perspective view of a fastener comprising a portion of the alternate means;

FIG. 9 is a plan view of the fastener of FIG. 8; and

FIG. 10 is a fragmentary side-elevational-sectional view taken along reference lines 10--10 of FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is illustrated in the accompanying drawings wherein similar components bear the same reference numerals throughout the several views. Reference is first made briefly to FIG. 5 wherein a typical hydraulic control system 10 is schematically illustrated. The system 10 is adapted to drive the actuators or outputs 12 along a common manifold. These outputs may consist of motors, cylinders, rotary actuators, etc.

In accordance with the present invention, such a system may easily be constructed by interconnecting a plurality of modular units, each such unit containing one of the elements called for in the schematic drawing. Thus, for example, in order to actuate motor 12a the various components contained within the subsystem 14 defined by the broken line border are required. This subsystem includes return and feed lines 16 and 18 which provide the actuating fluid to the subsystem from a pump 17 and supply reservoir 19 and returns the same; a reducing valve 20; a directional valve 22 and flow control valves 24. Together these components drive motor 12a in a desired manner. It should be realized that further along the manifold formed of the feed and return lines other subsystems formed of other components of various types are used to simultaneously drive and actuate their associated outputs.

Referring now briefly to FIG. 6, the circuit of FIG. 5 is shown formed of the modular units of the present invention. Thus, the feed and return lines, 18 and 16, are both contained in the manifold unit 28, the reducing valve 20 is contained in unit 30, the directional valve 22 is contained in unit 32 and the flow control valves are contained in unit 34. The output motor 12a, (not shown in FIG. 6), is connected to cylinder ports in the manifold block through suitable tubing in a manner to be described forthwith.

The manifold unit 28 has both its ends mounted to other similar units each having its feed and return lines in aligned registry. The ends 36 and 38 of the manifold are sealed and connected to the fluid pump and reservoir not shown. The manifold units are mounted on a platform 40 and, as shown in FIGS. 3 and 4, shock mountings 42 such as rubber pads may be provided between the manifold units 18 and the platform 40 if desired.

Reference is now made to FIGS. 1 through 4 wherein the details of the modular hydraulic system units of the present invention are shown. In FIGS. 1 and 2, the details of a manifold unit 28 and a typical component unit such as the flow control valve unit 34 are illustrated. The manifold unit 28 is generally rectangular in shape and includes front and rear walls 44 and 46, end walls 48 and 50, and top and bottom walls 52 and 54. The bottom wall 54 includes two axially aligned threaded holes 56 to enable the unit to be bolted to base 40. Two horizontal passageways or channels 58 and 60, extend completely through the manifold unit from end wall to end wall and terminate on each of the end walls. These passageways, when suitably connected, define the feed and return lines 18 and 16 of the system. It is to be noted that each of the terminals on end wall 50 are defined by a recessed channel 62 counterbored into the end wall and extending completely around the passageway terminals. The terminals on the other end wall, 48, are substantially flush with the end wall. The recesses 62 serve as seats for an "O" or other suitable gasket so that when the flush wall 48a of an identical manifold 28a is brought against the recessed wall an effective seal may be formed. Similarly, the flush wall 48 would serve to seal the recessed wall 50b, of an identical manifold 28b.

There are four vertical passageways, 64, 66, 68 and 70, extending partially through the manifold unit from the top surface 52. The vertical passageways terminate at openings on the surface which are substantially flush with the top surface. Two of the vertical passageways, 64 and 66, each communicate with one of the horizontal passageways 58 and 60 and are connected to the center of their respective passageways. The remaining passageways extend downwardly into the manifold unit and are connected to horizontal passageways which terminate in cylinder ports 65 and 67 on the unit rear. The motor 12a or other actuator is connected to ports 65 and 67.

In drilling the various passageways through the unit, it is sometimes necessary to drill a guide bore such as passageway 72, which terminates on wall 50 in recess 74. This passageway may be sealed with a conventional plug, which must be recessed below the surface of wall 50, or by means of an "O" ring inserted within recess 74, between wall 50 of the present unit and wall 48a of an adjacent unit. The latter method, however, does tend to produce additional forces tending to separate the adjacent units, and hence, is not suggested for high pressure systems.

As shown, recessed chambers 76 and 78 extend inwardly from the front and rear surfaces, respectively. Recess 76 is generally rectangular and is spaced inwardly of the top, bottom and end walls. Recesses 78 extend to the top and bottom walls, are spaced inwardly from the end walls, and are separated by a center divider 80. The front recess 76 provides a convenient compartment for receiving the electrical connections to be associated with the hydraulic system and in this connection openings 82 and 84 are provided in the end walls to permit passage of the electrical leads. Openings 82 and 84 are extended to front wall 44, thus enabling the electrical leads to be set into the unit without requiring snaking from unit to unit.

Recesses 76 and 78 also serve the important function of providing access to rear portions 86 and 88 of end walls 50 and 48, respectively. This permits several manifolds to be fastened to one another in end-to-end fashion without requiring that the fastener extend entirely through the unit.

It is undesirable to have the fastener extend entirely through the housing since this limits the pressure to which the manifold can be subjected since the maximum pressure is a function of the amount of elongation of the fasteners (leakage between adjacent units will occur when the fastener stretches enough to destroy the seal between the adjacent units), which in turn is a function of the initial length of the fastener. Thus, the manifold units 28 of the present invention are provided with four holes 90 drilled through end wall 48 into chambers 76 and 78 and four threaded holes 92 extending through end wall 50 into chambers 76 and 78. The holes 90 and 92 are in aligned registry so that threaded fasteners such as socket head bolt 94, may be positioned in chambers 76 and 78 and passed through openings 90 to engage the threaded openings 92b of another similar manifold 28b. Similarly fasteners can be positioned through openings 90a of an identical manifold 28a, to engage the threaded openings 92 thereby enabling the units to be connected. In this manner, the bolts 94 need only be sufficiently long to pass through the end wall openings 90 to engage the threaded openings of the manifolds to be joined. Four threaded holes 96 are also provided extending downwardly from top surface 52 and disposed about the vertical openings 64, 66, 68 and 70. A removable front plate 97 may be provided to protect the electrical connections in chamber 76, and in this regard aligned holes 99 and 101 are provided on the plate and unit to facilitate fastening. An opening 98 in plate 97 permits external electrical leads to be interconnected with the leads in the chamber as required.

A typical component unit 34, in accordance with the present invention, is also shown in FIGS. 1 and 2. Component unit 34 is also generally rectangular in shape and includes front and rear walls 98 and 100, end walls 102 and 104, and top and bottom walls 106 and 108. The component unit contains therein any hydraulic component, as, for example, the flow control valve, and the vertical passageways extending therethrough (to be described forthwith) bring the component in operative contact with the hydraulic fluid of the manifold and other associated components. Four passageways, 110, 112, 114 and 116 extend vertically through the unit in aligned registry with vertical passageways 64, 66, 68, and 70, respectively, of the manifold unit. Recessed channels 118 extend about the bottom terminals of the passageways while the top terminals are substantially flush with top surface 106. Recessed channels 118 serve to seat "O" rings or similar gaskets so that an effective seal may be drawn between the vertical passageways of unit 34 and those of the manifold unit 28 or between unit 34 and another similar unit such as 30. As shown in FIG. 3, a flow control valve such as 113 may be connected to the vertical passageways by suitable horizontal passageways 115 for additional control. The flow control valve 113 is suitably bolted to the exterior of unit 113. It should be noted that valve 113 provides the function for which this particular block was designed to accomplish.

The four passageways 110, 112, 114 and 116 include tank and return passageways 110 and 112 and two intracomponent connecting passageways. If required, further passageways may also be provided to divert all or part of the hydraulic fluid flow for some additional function. These additional passageways could be connected to the tank, return, or intracomponent passageways and then terminate on the surface of the unit for receiving the additional function component (such as 113). Since it is essential to the present invention that the various vertical and horizontal passageways of the units be in aligned registry with similar passageways of other units, cross drilled holes 120 are utilized to divert the passageway around other passageways to develop the desired function. These holes are later plugged to ensure against leakage if they are not used to connect to some outside component as previously described.

As in the horizontal coupling of the manifold units and for the same reason, it is desirable to vertically couple the various units to one another with the shortest possible fasteners. To this end vertical holes 122 are provided disposed about passageways 110, 112, 114 and 116 and aligned with the threaded openings. Unique socket head cap screws are utilized to effect the vertical coupling. As shown in FIG. 1, each of the bolts 124 includes a threaded portion 126 extending downwardly from an enlarged cap 128. A socket 130 extends downwardly from the top surface 132 of the bolt and a threaded recess 134 is disposed below the socket. The threaded portion 126 is designed to engage the threaded recess of another similar bolt.

Referring now to FIG. 4, it is noted that each hole 122 is provided with an enlarged top portion 136 designed to accommodate the cap 128 of bolt 124. In operation, a first unit, for example 34, is placed over the manifold unit 28 with its vertical passageways 110, 112, 114 and 116 aligned with passageways 64, 66, 68 and 70 and suitably sealed with "O" rings 138. Bolts 124 are then passed through openings 122 of unit 34 to engage the threaded holes 96 of unit 28. Another unit, for example 30, is then positioned above unit 34 with its passageways aligned with those of unit 30 and sealed with "O" rings. Bolts 124 are then passed through the openings 122 of unit 32 to engage the threaded portion of the heads of the bolts fastening unit 30 to the manifold. In a similar manner additional component units could be vertically added.

The method described above for coupling adjacent units has been found to operate satisfactorily under very high pressures which are sufficient for most uses. In the event that the system is to be operated in the ultra high pressure range, an alternate method of coupling adjacent units is disclosed in FIGS. 7 through 10. In accordance with this alternate coupling arrangement aligned channels 140 are drilled extending transverse to the units to be coupled as, for example, manifold units 28 and 28a. A short rod or pin 142, the diameter of which is substantially equal to that of channel 140 and the total length of which is equal to that of the combined depths of channels 140 and 140a is then inserted in both holes 140 and 140a. A hole 144 extends into each unit perpendicular to the pin receiving channel 140 and positioned proximal the end of channel 140. The portion 150 of hole 144 above the pin channel is threaded to accommodate a making thread on the top portion of the associated screw 148. As noted in FIGS. 8 and 9, pin 142 is provided with a slot 146 which tapers inwardly from the top surface. The length of slot 146 is substantially equal to the combined distance of channels 140 and 140a measured to screw holes 144 and 144a. Socket head tapered shoulder screws 148 are used to secure the pin in position and in this connection it is to be noted that the portion 150 of hole 144 above the pin channel 140 is counterbored sufficiently to accommodate the head 152 of screw 148. As noted before, this portion of hole 144 is also threaded. The shoulder 154 of screw 148 is tapered at substantially the same angle as slot 146.

In operation, the units are secured to one another in accordance with this alternate procedure by passing pin 142 through channels 140 and 140a of the units to be fastened with the top of tapered slot 142 aligned with the counterbored portion 150 of holes 144 and 144a and the bottom of the slot aligned with the bottom portion. Bolts 148 and 148a are then passed through the slot to engage threaded portion 150 and 150a respectively so that as the bolts are tightened the units are drawn toward one another.

Thus, in accordance with the above, a modular hydraulic system is provided wherein the various components are each contained in readily interconnected modules. The present invention thus facilitates the construction of a hydraulic system to perform any desired function and also permits, with relative ease, the replacement of any particular component to modify the system or to replace faulty or worn out parts.

Claims

Having thus described my invention, what is claimed is:

1. A hydraulic system adapted to be essentially free of outside piping and comprising a plurality of modular units adapted to be modulated horizontally and vertically having associated therewith hydraulic control component parts, each said unit is substantially rectangular having opposed end wall surfaces, top and bottom wall surfaces and front and rear surfaces, at least one passageway extending through each of said units communicating with the associated component part and terminating on at least one surface of the unit, a pair of opposed surfaces of each said unit wherein each surface of said opposed pair is adapted to be coupled to the opposite surface of the corresponding pair of opposed surfaces of another unit with adjacent units in surface-to-surface contact and the passageways terminating on abutting surfaces of adjacent units in aligned registry, said modular units including at least a first manifold unit and a second manifold unit, said manifold units being horizontally disposed and coupled to one another in end-to-end relationship, each of said manifold units having a first passageway extending between the unit end walls, a second passageway extending between the unit end walls, a center portion of each passageway, a third passageway connected to said first passageway center portion and terminating on the top wall surface of said manifold, and a fourth passageway connected to said second passageway center portion and terminating on said top surface, and means for coupling adjacent units to one another including screw means extending partially through each of the adjacent units, said screw means including a one piece cap screw, said screw including a head end, an integral enlarged cap portion extending downwardly from said head end, a threaded portion extending integrally downwardly from said cap, a socket recess extending into said cap from said head end, and a threaded bore disposed within said cap below said socket, the threads of said bore being adapted to engage the threaded portion of another similar screw whereby tightening of said first screw will cause tightening to be imparted to said similar screw.

2. The invention in accordance with claim 1 further comprising electrical servicing means coupled to each of said manifold units.

3. The invention in accordance with claim 1 wherein said system further comprises a unit containing a direction control valve coupled to at least one of said manifold units, said direction control unit including two passageways extending from the bottom surface of the unit into the unit interior in operative contact with the inlet of the direction control valve, said two passageways being in aligned registry with the third and fourth manifold passageways, two additional passageways in operative contact with the outlet of the direction control valve terminating on the top surface of said direction control unit, and a service unit mounted above said directional control valve unit, said service unit having vertical passageways in aligned registry with said direction control unit terminals, said service unit passageways communicating with a service device within said service unit; wherein one of said direction control unit top and bottom surfaces includes gasket receiving means and is adapted to be sealed by the opposite surface of another unit.

4. The invention in accordance with claim 1 further comprising gasket receiving means disposed upon one surface of each said opposed pairs, gasket means positioned within the aforementioned receiving means, and wherein the other surface of each said opposed pair is adapted to cooperate with said gasket means to form a seal between adjacent units.

5. The invention in accordance with claim 4 wherein said gasket receiving means of each said one surface comprises a recessed channel disposed about the terminal of each of the passageways terminating on that surface and said gasket means comprises an "O" ring seated within each said recess.

6. A hydraulic system adapted to be essentially free of outside piping and comprising a plurality of modular units adapted to be modulated horizontally and vertically having associated therewith hydraulic control component parts, each said unit is substantially rectangular having opposed end wall surfaces, top and bottom wall surfaces and front and rear surfaces, at least one passageway extending through each of said units communicating with the associated component part and terminating on at least one surface of the unit, a pair of opposed surfaces of each said unit wherein each surface of said opposed pair is adapted to be coupled to the opposite surface of the corresponding pair of opposed surfaces of another unit with adjacent units in surface-to-surface contact and the passageways terminating on abutting surfaces of adjacent units in aligned registry, said modular units including at least a first manifold unit and a second manifold unit, said manifold units being horizontally disposed and coupled to one another in end-to-end relationship, each of said manifold units having a first passageway extending between the unit end walls, a second passageway extending between the unit end walls, a center portion of each passageway, a third passageway connected to said first passageway center portion and terminating on the top wall surface of said manifold, and a fourth passageway connected to said second passageway center portion and terminating on said top surface, and means for coupling adjacent units to one another including screw means extending partially through each of the adjacent units, said system further comprising a unit containing a direction control valve coupled to at least one of said manifold units, said direction control unit including two passageways extending from the bottom surface of the unit into the unit interior in operative contact with the inlet of the direction control valve, said two passageways being in aligned registry with the third and fourth manifold passageways, two additional passageways in operative contact with the outlet of the direction control valve terminating on the top surface of said direction control unit, and a service unit mounted above said directional control valve unit, said service unit having vertical passageways in aligned registry with said direction control unit terminals, said service unit passageways communicating with a service device within said service unit, wherein one of said direction control unit top and bottom surfaces includes gasket receiving means and is adapted to be sealed by the opposite surface of another unit, said directional valve unit and said service unit including a plurality of bores passing therethrough from said unit top to bottom surfaces, the bores of said directional valve unit and service unit being in aligned registry; a counterbored portion of each said bore extending downwardly from said unit top surfaces, an equal plurality of threaded bores extending downwardly from said manifold unit top surface in aligned registry with said directional valve unit and said service unit bores, and said coupling means includes a cap bolt extending downwardly through each said service unit bores and each said directional valve unit bores, each said bolt having an enlarged cap portion adapted to seat on top of said counterbored portion and a threaded portion adapted to extend beyond said unit bottom surface whereby the bolts extending through said service unit extend beyond the bottom surface of said service unit to extend into each directional control valve unit and the bolts extending through said directional control valve unit extend directional valve unit bottom, surface to engage said manifold unit threaded bore, said cap screws each include a head end, an enlarged cap portion extending downwardly from said head end, a threaded portion extending downwardly from said cap, a socket recess extending into said cap from said head end, and a threaded bore disposed within said cap below said socket, the threads of said bore being adapted to engage the threaded portion of another similar screw.

7. The invention in accordance with claim 6 wherein said cap screw includes a head end, an enlarged cap portion extending downwardly from said head end, a threaded portion extending downwardly from said cap, a socket recess extending into said cap from said head end, and a threaded bore disposed within said cap below said socket, the threads of said bore being adapted to engage the threaded portion of another similar screw.

8. A hydraulic system adapted to be essentially free of outside piping and comprising a plurality of modular units adapted to be modulated horizontally and vertically having associated therewith hydraulic control component parts, each said unit is substantially rectangular having opposed end wall surfaces, top and bottom wall surfaces and front and rear surfaces, at least one passageway extending through each of said units communicating with the associated component part and terminating on at least one surface of the unit, a pair of opposed surfaces of each said unit wherein each surface of said opposed pair is adapted to be coupled to the opposite surface of the corresponding pair of opposed surfaces of another unit with adjacent units in surface-to-surface contact and the passageways terminating on abutting surfaces of adjacent units in aligned registry, said modular units including at least a first manifold unit and a second manifold unit, said manifold units being horizontally disposed and coupled to one another in end-to-end relationship, each of said manifold units having a first passageway extending between the unit end walls, a second passageway extending between the unit end walls, a center portion of each passageway, a third passageway connected to said first passageway center portion and terminating on the top wall surface of said manifold, and a fourth passageway connected to said second passageway center portion and terminating on said top surface, and means for coupling adjacent units to one another including screw means extending partially through each of the adjacent units, each of said manifold units further including a cavity extending inwardly from said manifold unit front surface and a cavity extending inwardly from said unit rear surface, said cavities each being spaced from said end walls whereby to define rear surfaces for said end walls and to provide access to said end wall rear surfaces, said coupling means include screw means, a tapped bore extending through one end wall to said end wall rear adapted to engage said screw means and an opening in the other end wall to the rear surface of said other end wall adapted to allow said screw means to pass through to engage the tapped bore of the other end wall of another similar unit, said end wall openings and tapped bores being in aligned registry.

9. A hydraulic system adapted to be essentially free of outside piping and comprising a plurality of modular units adapted to be modulated horizontally and vertically having associated therewith hydraulic control component parts, each said unit is substantially rectangular having opposed end wall surfaces, top and bottom wall surfaces and front and rear surfaces, at least one passageway extending through each of said units communicating with the associated component part and terminating on at least one surface of the unit, a pair of opposed surfaces of each said unit wherein each surface of said opposed pair is adapted to be coupled to the opposite surface of the corresponding pair of opposed surfaces of another unit with adjacent units in surface-to-surface contact and the passageways terminating on abutting surfaces of adjacent units in aligned registry, said modular units including at least a first manifold unit and a second manifold unit, said manifold units being horizontally disposed and coupled to one another in end-to-end relationship, each of said manifold units having a first passageway extending between the unit end walls, a second passageway extending between the unit end walls, a center portion of each passageway, a third passageway connected to said first passageway center portion and terminating on the top wall surface of said manifold, and a fourth passageway connected to said second passageway center portion and terminating on said top surface, and means for coupling adjacent units to one another including screw means extending partially through each of the adjacent units, said coupling means comprising a bore extending inwardly from the coupling surface of each unit to be coupled transverse to said surface, an elongated pin having a first portion adapted to extend into the bore of a first unit to be coupled and a second portion adapted to extend into a similar bore on another unit, a tapered longitudinal slot on said pin extending between said first and second portions, a screw hole disposed within each said unit transverse to said unit bore and terminating on a surface perpendicular to said bore, said screw hole comprising, a threaded portion extending between said bore and said perpendicular surface and a portion disposed on the other side of said bore extending into the unit interior from said bore, and, a threaded fastener having a tapered shoulder portion, the taper of which corresponds to the taper of said slot and a threaded portion adapted to engage the threaded portion of said screw hole wherein the total length of said slot corresponds to the combined distance from said surface to said screw hole of said first unit and the corresponding distance of said other unit.

10. A modular unit adapted to be modulated horizontally and vertically and for a hydraulic control system adapted to be essentially free of outside piping, interior portions of said unit adapted to have an associated hydraulic control component part, interior surfaces defining at least one passageway connected with said component and adapted to transmit hydraulic fluid to said component, said passageway terminates on at least one exterior surface of said unit; means for coupling said modular unit to another unit in a horizontal direction and means for coupling said modular unit to another unit in a vertical direction, said means comprising at least one pair of opposed surfaces of said unit, each surface of said pair being adapted to be coupled to the opposite surface of the corresponding pair of another unit; and coupling means includes screw means extending partially through said unit and adapted to extend partially through said adjacent unit, said screw means including a one piece cap screw, said screw including a head end, an integral enlarged cap portion extending downwardly from said head end, a threaded portion extending integrally downwardly from said cap, a socket recess extending into said cap from said head end, and a threaded bore disposed within said cap below said socket, the threads of said bore being adapted to engage the threaded portion of another similar screw whereby tightening of said first screw will cause tightening to be imparted to said similar screw.

11. The invention in accordance with claim 10 further comprising electrical service means coupled to said unit.

12. The invention in accordance with claim 10 wherein said unit is substantially rectangular having opposed end wall surfaces, top and bottom wall surfaces and front and rear wall surfaces.

13. The invention in accordance with claim 10 wherein said unit comprises a manifold unit having a first passageway extending between the unit end walls, a second passageway extending between the unit end walls, a center portion of each passageway, a third passageway connected to said first passageway outer portion and terminating on the top wall surface of said manifold, and a fourth passageway connected to said second passageway center portion and terminating on said top surface.

14. The invention in accordance with claim 10 further comprising gasket receiving means disposed upon one surface of said opposed pair of surfaces wherein the other surface of said pair is adapted to cooperate with the gasket receiving means of another similar unit to form a seal between said unit and said other unit.

15. The invention in accordance with claim 14 wherein said gasket receiving means of each said one surface comprises a recessed channel disposed about the terminal of each of the passageways terminating on that surface and said gasket means comprises an "O" ring seated within each said recess.

16. A modular unit adapted to be modulated horizontally and vertically and for a hydraulic control system adapted to be essentially free of outside piping, interior portions of said unit adapted to have an associated hydraulic control component part, interior surfaces defining at least one passageway connected with said component and adapted to transmit hydraulic fluid to said component, said passageway terminates on at least one exterior surface of said unit; means for coupling said modular unit to another unit in a horizontal direction and means for coupling said modular unit to another unit in a vertical direction, said means comprising at least one pair of opposed surfaces of said unit, each surface of said pair being adapted to be coupled to the opposite surface of the corresponding pair of another unit; and coupling means includes screw means extending partially through said unit and adapted to extend partially through said adjacent unit, said unit comprising a manifold unit having a first passageway extending between the unit end walls, a second passageway extending between the unit end walls, a center portion of each passageway, a third passageway connected to said first passageway outer portion and terminating on the top wall surface of said manifold, and a fourth passageway connected to said second passageway center portion and terminating on said top surface.

17. An improved one piece cap screw adapted to extend partially into adjacent modular units of a hydraulic control system to cooperate in coupling the adjacent units to one another, said screw including a head end, an integral enlarged cap portion extending downwardly from said head end, a threaded portion extending integrally downwardly from said cap, a socket recess extending into said cap from said head end, and a threaded bore disposed within said cap below said socket, the threads of said bore being adapted to engage the threaded portion of another similar screw whereby tightening of said first screw will cause tightening to be imparted to said similar screw.