US3272232A - Distribution block for hydraulic valve - Google Patents

Description

Sept. 13, 1966 R. LAUMO NT DISTRIBUTION BLOCK FOR HYDRAULIC VALVE Filed NOV. 12, 1963 2 Sheets-Sheet 1 INVENTOR LAUMONT Aeevs.

ROGER Sept. 13, 1966 R. LAUMONT D'IIS'I'RIHU'IION BLOCK FOR HYDRAULIC VALVE 2 Sheets-$heet 2 Filed Nov. 12, 1963 INVENTOR ROGER LAUM NT v 3,272,232 DISTRIBUTION BLOCK FOR HYDRAULIC VALVE Roger Laumont, Nogent-sur-Marne, France, assignor to Hydro-Meca, Paris, France, a company of France Filed Nov. 12, 1963, Ser. No. 323,006 Claims priority, application France, Nov. 16, 1962, 915,665, Patent No. 1,347,205 9 Claims. (Cl. 137-59612) This invention relates to an improved distributor block, or casing, for housing a hydraulic valve, or the like. As is well known, hydraulic valve appliances necessarily comprises mobile parts which are subjected, together with the fixed parts supporting them, to pressure differences which are often considerable. This means that the moving parts and their guides in the fixed parts must be made with great accuracy, usually by machining, to prevent leaks between the high and low pressure fluid circuits. The slightest distortion to which all, or part, of the fixed elements may be subjected leads to various disadvantages including seizures of the moving parts, deterioration of said parts, defective working, and even serious accidents when the parts that seize have a safety function.

Moreover, it is also known that it is most desirable to standardize manufacture of hydraulic appliances to facilitate their production and eventual repair and also to enable their modification, or adaptation, to new conditions of use. This is particularly true for multiple slide-valve units which are universally used.

Considering the conditions briefly described above, it is customary to make the distribution block unit of a hydraulic valve in the form of a casing in which passage channels pass the hydraulic liquid under control of a slide-valve. These casings are most t'requently cast from cast iron and the channels traverse them from side to side to avoid technical casting problems. In assembling a distribution block, several of these casings are piled one on top of another, their opposite faces, into which the circulation channels emerge, being suitably machined. Then the two end casings are provided with covers and tierods traversing all the casings and connecting them together and which by tightening exert, a seal-tightness between all the casings.

Although its seems simple, this conventional construction has a considerable number of disadvantages. The bearings of each casing in which the valves slide as Well as the slide-valves themselves, are very carefully machined. In mass production, the slide-valves and casings are paired together according to closeness of fit by actual measurements. When the various casings are closed and tied together, the mutual tightening to which they are subjected has the eflect of setting up distortions which, nearly always, are greater than acceptable machining tolerances between the slide-valves and their guiding bearings. defective, and it frequently occurs that machining corrections have to be made after several casings have been piled and secured together.

These disadvantages, reoccur every time the valve is disassembled for repair and reassembled, resulting in relatively high costs of such units.

To overcome these disadvantages, distribution units have been made in which one assembly casing is cast in one piece, i.e., that a single casing is cast so as to enable the positioning therein of as many as ten slide-valves.

This one piece foundry casting is diflicult to make for several reasons. All the passage ducts must be cast inside a completely closed part except for the opening necessary for inserting and positioning the slide-valves, the

It follows that the operation of the valves is often United States Patent ice various check valves and other accessories assembled in the distribution block.

It is also extremely difl'lcult to properly clean the complexly shaped circulation channels inside the casting, for the usual cleaning means, such as shotting or sanding, cannot be used as they result in traces of foundry sand adhering to the walls which are then carried along by the hydraulic fluid, thus causing damage to the slide-valves and other moving parts.

Furthermore, the machining of the bearings for the slide-valves is a diflicult operation because accessibility to the inside of cast part is awkward.

The present invention obviates the disadvantages mentioned above and enables the using either of well-known casting processes, when the parts must be made of cast iron, or casting under pressure for increased rigidity with lighter metals.

According to the invention, the carrier casings for hydraulic equipment, more particularly for carrier casings containing sliding elements of great precision, as well as all other moving elements in which seal-tightness between the moving and fixed parts is a result of machining accuracy, is made by casting a part in which at least two partitions are provided extending longitudinally on either side of each moving element, said two partitions being connected by cross bars which are also connected, together with said partitions, both to the bottom of the casing and to a perforated plate, or flange, formed on top of said casing so as to produce a honeycombed structure in which the moving element is placed, all the hydraulic circuits being confined by the honeycombs and emerging in the perforations of the perforated plate. This structure is then covered by a cover whose mechanical resistance characteristics, at least with regard to bending and twisting, are appreciably less than the comparable characteristics of the casing, said cover being itself perforated to form a support for the accessories and a linking element for the ducts which must be connected to the hydraulic appliance.

Various other characteristics of the invention will become apparent from the detailed description which follows.

An embodiment of the invention is shown by way of non-restrictive example, in the attached drawings.

FIG. 1 is a plan view from above of a distributor unit according to the invention in which the cover plate is omitted.

FIG. 2 is a section taken along the line IIII of FIG. 1 with the cover plate added.

FIG. 3 is apartial section taken along the line III-III of FIG. 1.

According to the invention, for producing hydraulic appliances which must comprise sliding elements and which must have very close machining tolerances and/ or elements in which as complete a seal-tightness must exist between the coplanar contact parts and surfaces, a casing is made for containing the sliding elements with close manufacturing tolerances by casting in a single piece and so as to confine, at least in the vicinity of said high precision mobile elements, components such as guards, small bars and ribs forming a structure of great rigidity surrounding and supporting said sliding elements.

In other words, the structure of the one-piece casings according to the invention is a honeycombed structure in which all its channels, ducts, slots or openings, through which the fluid must circulate to be brought into relation with the high precision sliding elements or to reach the chambers, cavities, housing or other enclosures in which these elements move, emerge on a one plane face of said casing. This face has a flat surface for engagement by a cover also preferably made by casting. The cover is als machined so that all the ducts, pipings and connections that must be connected to the hydraulic mechanism, need only be secured to this cover. Preferably said cover possesses rigidity characteristics appreciably less than those of the casing so that the various stresses likely to be transmitted by mechanical support means for the hydraulic device are applied to the cover to distort only the cover, without being transmitted to the casing itself which receive only the pressure stresses transmitted by the circulation of the pressure fluid.

In that which follows, the invention is described with more particularity and with reference to a multiple slidevalve unit.

In the example illustrated is shown a peripheric frame 1 having an integral bottom 2 to define a casing. In a device of this type, the high precision elements are slidevalves 3, 3a etc., which can be of any number and also one or more check valves 31 of piston shape which must be able to slide easily in the bearings 4 provided for this purpose, without leaks occurring. Therefore the machining, both of the guiding bearings and slide-valves, must be carried out with an accuracy in the order of microns, and it is obvious that any distortion of the casing would tend to render this machining accuracy useless if it results in a seizure of the sliding elements, or in unacceptable wear, suflicient to start leakage of pressure fluid between the various compartments and channels of different pressure. a

To prevent such distortions in the case, partitions 5 are formed on either side of the bores provided for housing the sliding elements 3, and extend the entire height of the casing. These partitions are joined together and formed integral i.e. in one piece with the bottom 2 and the partial top flange 6 extending over said bores.

This top flange has openings or slots, such as 7, for introducing mechanical components that must be placed inside the casing for cooperating with the sliding elements 3, such as springs 8 and bearing cupolas 9. Transfer channels such as 10 are also formed to pass through flange 6 and to emerge at the top part surface of said flange in a space confined between the vertical partitions 5.

FIG. 3 shows that the partitions 5 also confine openings 11, 11a intended to effect communication between the various compartments which must be connected inside the distribution block, these openings or slots being made in said partitions between the lower surface of the top flange 6 and the upper surface of the bottom 2. These passages lighten the partitions, without appreciably reducing their mechanical strength.

The described construction further utilizes crossbars such as 12 extending between the partitions and the frame and integral therewith but positioned so as not to close the various slots and transfer channels. The crossbars ensure the transversal rigidity of the casing.

According to another characteristic of the invention, the walls that border the transfer channels and the various slots opening in the top flange 6, are vertical Walls or have only a slight casting clearance, and these channels and slots thus extend in depth to the surface of the bottom 2, as is clearly visible in FIG. 2, where the bottom of the slots and channels is denoted by 13. FIGURE 3 shows the arrangement of the crossbars 12 Which start from the bottom 2 and extend upwardly to the top flange 6, to define with the partitions S and the flange 6, a honeycomb structure, of which all the honeycomb openings emerge on the upper surface of said flange 6.

Owing to the very special design described above, the great mechanical rigidity of the casing resulting therefrom is obvious, and this particular structure enables an easy production of said casing by known casting processes, seeing that all the slots and channels emerge on the same face.

The casting processes that can be used are sand or chill processes and casings can also be produced by casting under pressure, which, for numerous applications, makes it possible to make the casing not of cast iron, but of various light alloys, while retaining mechanical strength qualities that are distinctly greater than those of other constructions.

Another advantage arising out of the described casing, is that the casing can be very easily cleaned, especially when it is made by sand casting because then simple, known techniques, such as shotting may be used and the casing not having ducts of complex shape does not obstruct or impede circulation of the cleaning projectiles.

Other advantages of the described construction include ease of machining since the openings through flange 6 permit access for lathe tools to machine the bearings 4, the bore for containing the slide-valves 3 as well as grooves for housing circlips or other stop elements 14 and seal ring 15 (FIG. 2).

When the casing is made by casting various light alloys under pressure, it is also possible to make the slide-valve, or slide-valves, or other similar components 3 of the same material, or a material having comparable expansion characteristics. When the casing is made of light metal, the slide-valves 3 and check valves 31 can also be made of light metal, whose surface is then treated so as to possess a great surface hardening, which can be easily effected by hard chroming, for example.

The described casing is closed by a cover 16, shown in FIG. 2. This cover is a plate that can be thick, but whose walls have dimensions, thickness and shape such that its mechanical resistance to bending and twisting is very appreciably less than that of the casing.

For example, the cover 16 can be flat, although relatively thick, so that when engaged against the upper surface of flange 6 a good and tight fit to the casing can be ensured by screws (not shown) which traverse the cover and are screwed into tappings 17 in the casing. Then if distortion occurs, it will only affect the cover which has no guiding function for the high precision sliding elements. I

The cover is provided with the necessary channels 18 to afford communication between the transfer channels, or ports, 10 of the casing and to link these channels, or ports, with the external ducts communicating with other appliances of a hydraulic installation. It has been found advantageous to support accessory elements of a hydraulic installation, for example, over-pressure check valves, which are components which must be easily taken down, inside the cover, and this is shown in FIG. 2 where the over-pressure check valves 19 are formed by cartridges 20 positioned in bores 21 provided in the cover. This cartridge arrangement of the check valves allows continued satisfactory operation despite eventual distortion of the cover.

Other necessary components can, of course, also be fitted in the cover which, moreover, is provided with lugs 22 or, other suitable portions enabling the securement of the distributor block unit which is thus supported by the relatively distortable cover rather than the casing to insulate the casing from mechanical stresses which may be imposed by the support device.

Considering operation of the structure according to the invention as represented in the drawings, channels 18 and 18a of cover 16 are connected to the member to be actuated for instance a double acting jack, a motor, etc. High pressure is supplied in channels a, b, a b from supplying high pressure chamber HP and safety valve 31 known per se. Channels C and chambers 7 are respec tively connected to openings 11, 11a themselves connected to a low pressure liquid tank not shown.

Sliding elements 3, 3a, etc. are provided with included non-return valve d and d and a set of over pressure checkvalve 19 is provided in the cover 16 in relation with each set of channels 18, 18a.

The sliding elements 3, 3a, etc., are normally held in neutral position by spring 8 whereby high pressure is transmitted by channels a, b and channel e to the successive channels a b corresponding to sliding element 3a, etc.

Upon actuation of sliding element 3 to the left, for instance, channel b is caused to communicate through nonreturn valve d with channel 18a, which is thus supplied with high pressure. Simultaneously, channel 18 is caused to communicate through non-return valve d with channel C and thus with the low pressure tank by the intermediary of opening 11a. In case of over pressure in channel 180, check-valve 19 is opened to discharge into chamber 7 and to opening 11a. Upon actuation of element 3 to the right, the reverse occurs and channel 18 is supplied with high pressure. Simultaneously channel 18a is caused to communicate with the low pressure tank. The presence of too high a pressure in channel HP FIG. 3 opens check valve 3, and bleeds part of the pressure fluid to cavity 11a and the low pressure tank.

An additional advantage of the described construction is that the same flexibility of utilization is obtained as with known constructions particularly where it is necessary to connect the casings of several distribution blocks together and eifect communication of the high and low pressure circuits of the casings of successive distribution blocks with each other. This can be obtained in two ways according to the invention.

Certain of the ducts 18 formed in the cover can be provided with plugs for which it is possible to substitute ferrules for connecting two successive distribution blocks. Moreover, it is also possible, as shown in FIG. 1, without reducing the rigidity of the casing, to provide in the parts referred to by 1a, 1b, ports 23 which are normally closed by plugs, but which are intended to receive connecting ferrules 24, of which one is shown in broken lines, and whose middle part at least is so formed that these ferrules can bend to a certain extent, so that they are capable of absorbing distortions without the risk that the stresses set up by these distortions are able to reflect in the casing itself.

In order to eliminate all risk of leakage, even when the cover has suffered some distortions, cavities 25 are formed on its lower face which engages the upper face of the flange of the casing. Cavities 25 house flexible washers 26, which are compressed by the pressure of securement means 17 lessening the pressure necessary to be applied to the cover against the top of the flange 6 of the casing.

The invention is not restricted to the form of embodiment shown and described in detail, for various modifications can be applied to it without going outside of its scope. For example, what is denoted in the foregoing as the cover may form the underneath of the distribution block.

I claim:

1. A distribution block for a hydraulic control valve, of the type enclosing high precision sliding elements movable in chambers and defining interconnecting channels, passages, ducts and the like, which require liquid tight sealing between all moving and all fixed parts, comprising a casing formed of walls of cast metal in box-like shape and open at one side, at least two parallel, spaced partitions crossing said casing between a pair of opposite sides for housing between them a movable element, a flange on said partitions having perforations and partially closing said open side, said two partitions being connected by cross-bars which are also connected to the closed side of the casing and to said flange, said casing partitions, flange and cross bars being integrally formed in one piece, said partitions and cross bars having slots therethrough so as to form with said casing a honeycombed structure for receiving said movable elements and pressure fluid channels defining hydraulic circuits emerging in the open side of the casing through said perforations of the flange, and a support cover closing said casing and perforations of said flange, said cover being less mechanical resistant to bending and twisting than the casing and having openings for connecting pressure fluid ducts for the channels of the casing.

2. A distribution block for a valve according to claim 1 wherein the perforations in said flange are of a shape and dimensions corresponding to the honeycomb structure inside the casing so that the walls ofthe honeycomb are substantially vertical to facilitate casting of the casing as well as its subsequent cleaning.

3. A distribution block for a valve according to claim 1 wherein said cover includes cavities for enclosing accessory devices for controlling flow of pressure fluid.

4. A distribution block for a valve according to claim 1 wherein said casing comprises a bottom wall bordered by a peripheral upright wall, two of the sides of said upright wall being connected by said partitions for housing a slide valve to be guided in bearings confined by said cross bars, the spaces separating said crossbars defining transfer channels and passage ports for hydraulic pressure fluid and opening at the top of said casing, said cover having ducts therein corresponding to the various fluid transfer channels in said casing, said cover being fixed by screws to the casing, and seal-tight washers inserted between said cover and the perforated flange forming the top of the casing.

5. A distribution block for a valve according to claim 4, wherein said cover confines channels for putting certain of the honeycomb chambers of the easing into communication.

6. A distribution block for a valve according to claim 4, wherein said cover comprises fixing lugs for supporting the cover and easing as a unit.

7. A distribution block for a valve according to claim 4 wherein at least one honeycomb chamber confined between said partitions of the casing forms bearings for supporting an over-pressure check-valve placed parallel to said chamber between partitions for housing a slide valve.

8. A distribution block for a valve according to claim 4, wherein ducts are provided in the cover for connecting the high and low pressure fluid circuits to a second and similar casing of another valve.

9. A distribution block for a valve according to claim 4 wherein the casing has, in two of its external sides, thicker parts in which ports are provided normally closed by plugs and intended to receive distortable connections for connecting two successive distribution blocks together.

References Cited by the Examiner UNITED STATES PATENTS 2,651,324 9/1953 Hodgson et al. 137596.12 2,981,989 5/1961 Hatch 22200 3,010,167 11/1961 Kozinski 22-200 3,151,630 10/1964 Tennis 137-5962 3,152,610 10/1964 McAlfee 137-5962,

M. CARY NELSON, Primary Examiner.

MARCUS U. LYONS, MARTIN P. SCHWADRON,

Examiners.

Claims (1)

1. A DISTRIBUTION BLOCK FOR A HYDRAULIC CONTROL VALVE, OF THE TYPE ENCLOSING HIGH PRECISION SLIDING ELEMENTS MOVABLE IN CHAMBERS AND DEFINING INTERCONNECTING CANNELS, PASSAGES, DUCTS AND THE LIKE, WHICH REQUIRE LIQUID TIGHT SEALING BETWEEN ALL MOVING AND ALL FIXED PARTS, COMPRISING A CASING FORMED OF WALLS OF CAST METAL IN BOX-LIKE SHAPE AND OPEN AT ONE SIDE, AT LEAST TWO PARALLEL, SPACED PARTITIONS CROSSING SAID CASING BETWEEN A PAIR OF OPPOSITE SIDES FOR HOUSING BETWEEEN THEM A MOVABLE ELEMENT, A FLANGE ON SAID PARTITIONS HAVING PERFORATIONS AND PARTIALLY CLOSING SAID OPEN SIDE, SAID TWO PARTITIONS BEING CONNECTED BY CROSS-BARS WHICH ARE ALSO CONNECTED TO THE CLOSED SIDE OF THE CASING AND TO SAID FLANGE, SAID CASING PARTITIONS, FLANGE AND CROSS BARS BEING INTEGRALLY FORMED IN ONE PIECE, SAID PARTITIONS AND CROSS BARS HAVING SLOTS THERETHROUGH SO AS TO FORM WITH SAID CASING A HONEYCOMBED STRUCTURE FOR RECEIVING SAID MOVABLE ELEMENTS AND PRESSURE FLUID CHANNELS DEFINING HYDRAULIC CIRCUITS EMERGING IN THE OPEN SIDE OF THE CASING THROUGH SAID PERFORATIONS OF THE FLANGE, AND A SUPPORT COVER CLOSING SAID CASING AND PERFORATIONS OF SAID FLANGE, SAID COVER BEING LESS MECHANICAL RESISTANT TO BENDING AND TWISTING THAN THE CASING AND HAVING OPENINGS FOR CONNECTING PRESSURE FLUID DUCTS FOR THE CHANNELS OF THE CASING.

Images