US3286793A - Automatic reversing and metering device for central lubrication systems - Google Patents

Description

Nov. 22, 1966 H. BRICOUT 3,

AUTOMATIC REVERSING AND METERING DEVICE FOR CENTRAL LUBRICATION SYSTEMS Filed March 17, 1964 Fi g. 1 8 3 United States Patent 3,286,793 AUTOMATIC REVERSING AND METERING DE- VICE FOR CENTRAL LUBRICATION SYSTEMS Henri Bricout, Meudon, France, assignor to Societe anonyme dite: Societe dApplications des Machines Mott-ices, Issy-les-Moulineaux', Seine, France Filed Mar. 17, 1964, Ser. No. 352,476 Claims priority, application France, Mar. 19, 1963, 928,406 8 Claims. (Cl. 1847) This invention relates to automatic two-line or single line reversing and metering devices for central lubrication system s. p I

The devices of this type which are employed for controlling two-line systems constitute in reality reversing devices which assure successively the feeding of one and the other line. These reversing devices are generally relatively complex because the majority of them comprise a main slider and control pistons called pilot pistons.

Automatic reversing devices are already known which have only one slide member. These reversing devices have thus the advantage of being easier to machine and also less cumbersome because they have only one bore which is relatively short and accordingly it is necessary to grind only one slider. l

Such a reversing device is disclosed in U.S. Patent 3,027,973 filed April 3,1962. However, in certain special applications there exists the risk that the slider may lock in the center position or in one of the two end positions. In order to avoid this risk it is necessary to add to such a device appropriate safety means, for eiiample two accumulators'. These arrangementsprovide very satisfactory operation because they prevent effectively any risk of locking of the slider. But they are expensive and the operation is relatively sensitive.

Accordingly it is an object of the present invention to provide an automatic reversing and metering device ofthe type mentioned above, which is adapted to operate perfectly without any risk of locking of the single slider and without the necessity of adding any complementary safety means. v

The device according to the invention comprises a slider which is displaced in a translation movement, and provided with a collar adapted to occupy two positions.

In the first position the collar allows a communication between an upper conduit and a lower conduit,and in the second position the collar allows a communication between the lower conduit and a return conduit, and is characterized in that the slider is guided directly from the first position to the second position at least over the first portion of the travel by the pressure of the hind in the lower conduit;

The slider is guided at least over the last portion of the course from the first to the second position by the pressure of the fluid in the upper conduit.

The invention would be applied m'ost appropriately in a well-known distributor of the type having five-lines, with a closed center, constituted symmetrically relative to the line of the lower conduit, which allows the use of the distributor in a distribution system comprising two lubrication lines, or if desired, in a distribution system comprising only one lubrication line.

Under theseconditions this device operates in a twostroke cycle exactly like the reversing devices having a main slider and pilot pistons, and in view of this fact its operation can in no way be defective. However, this device has the advantage of being very inexpensive, as it comprises only one slider having two dollars.

Furthermore this device has the advantage of being applicable, without modification as an automatic discharge valve in the central lubrication systems having only one line, and which operate alternatively by pressure and 3,286,793 Patented Nov. 22, 1966 vacuum. In such systems the discharge valves are generally made in su-cha way that they require a manual operation. In fact, they comprise usual-1y a piston actuated by a spring which is compressed to a higher degree if one desires a higher pressure. The rod of this piston extends outwardly in a noticeable manner when a given pressure has been reached in the feeding-line, and this pressure pushes the spring back. Thus, this piston rod constitutes a signalling means which indicates to the operator when the rod appears that he must actuate the handle so that the lines can discharge. These valves require thus a continuous observation which constitutes a great inconvenience.

The device according to the invention may replace these valves without any modification and it allows to place automatically the single feeding line under pressure and provides subsequently its discharge.

The embodiment of the device according to the inven tion isdescribed hereafter by reference to the'accompanying drawing in which:

FIG. 1 is a longitudinal section of the device according to the invention,

FIG. 2. shows a view of a longitudinal section along line 2- 2 of'FIG. 1,

FIGS. 3, 4 and 5 are sectional views according to FIG. 1 showing the elements of the device in different positions during operation. I

The device illustrated in the drawing consists of a housing 1 in which a transverse bore is provided and whichcontains aslider spindle 4 comprising only two collars 3 and 3a. The" inlet or supply canal 5 for the lubricant under pressure leads into the bore 2 between the two displacement zones of collars 3 and 3a.

On each side of the axis of this inlet canal 5 two groups of symmetrical canals are disposed com-prising each:

A distribution or' output canal, respectively 6 and 6a, communicating with each of the two lines to be supplied,

A discharge or reservoir return canal, respectively 7 and 7a, and a branch canal, respectively 8 and 8a, connecting each of the distribution canals 6 and 6a with the corresponding end 9 or 9a of bore 2.

The location of the' openings of these dilferent canals and the disposition of the two collars 3 and 3a of the slider are such that in each of its end positions shown in FIGURES 1 and 4 the single slider of this device provid'es on the one hand a communication of the feeding canal 5 with the output canal 6 or 6a of one of the lines, and-on the other hand the connection of canal 6 or 6a of the other line with the corresponding discharge or return canal 7 or 7a leading to a lubricant reservor. Thus, in the position illustrated in FIG. 1 the canal 6 of one of the lines is connected to the feeding canal while the canal- 6a of the other line is placed in communication with the canal 7a which discharges into the reservoir.

In accordance with the essential feature of the invention the ends 9 and 9a of the bore are closed by plugs or piston members 10 and 10:: mounted slideably in the manner of pistons on these two ends of the slider. These plugs consist of an annular seal disposed around the corresponding ends 11 and 11a of the slider. According to an important feature of the invention the crosssection of each of these plugs is greater than the crossseetion of the collars 3 and 3a of the slider.

Each of these plugs is supported against a sleeve 12 or 12a engaged in a corresponding end of bore 2 and fixed to a small plate 13 or 13a disposed at the outside of housing 1. These two plates are connected by tie bars 14 mounted slideably in grooves 15 provided in housing 1. The length -'of these tie bars is greater than the length of the housing so that they provide a distance or interval between one of the plates 13 or 13a and the corresponding face of the housing when the other plate is 3 applied against the opposite face of the housing. Thus the plates 13 and 13a and their tie bars 14 constitute a movable assembly or carriage adapted to move in one and the other direction relative to the housing 1 within predetermined limits.

The ends 11 and 11a of slider 4 which slide freely in plates 13 and 13a so that the slider may move freely relative to the movable carriage. The end 11 of the slider is coupled to a curved spring susceptible of maintaining it in each of its operative end positions while allowing a displacement in relation to the excess feeding pressure to permit the reversing operations.

In the embodiment illustrated this spring consists of two curved blades 16 one end of which is hooked around a transverse pin 17 which extends between the two jaws or side plates of a head piece 18 mounted on the outer face of the plate 13 of the movable assembly. The opposite end of each of these spring blades is hooked around the end 11 of the spindle or more specifically around parallel pins 19 which are engaged in a groove 20 at this end of the slider, and thus firmly engage the latter, while the two parallel pins 19 are interconnected by braces 21.

An abutment consisting of a shaft 22 is disposed opposite the end 11 of the slider and extends between the two jaws of the head piece 18. The two braces 21 which are fixed to the endof the slider may abut against this shaft by their corresponding edge in one of the end positions of the slider (see FIGURES 1 and 2) and they may abut against the plate 13 by their opposite edge in the other end position of the slider (see FIGURE 4).

When the device is employed as automatic reversing means for feeding a two-line central lubrication system its operation is as follows: as stated above this device provides the feeding of the line or conduit which communicates with the output canal 6 when the slider is in the position illustrated in FIGURE 1, and the second line is in that case connected to discharge because canal 6a communicates with return canal 7a leading to the reservoir. In View of the fact that the surface of the slide plug is larger than the surface of collar 3 thepressure which is present at the end 9 of bore 2 in view of its connection with canal 6 by the intermediary of branch canal 8 assures that this plug is maintained'in a maximum position of displacement at the left end of the slider. However, this displacement is obviously limited by the position of plate 13a of the movable carriage against the opposite face of housing 1. The slider is thus maintained in the corresponding position by the action of spring 16.

When the different metering devices of the feeding line have been in operation the pressure in this line increases so that the pressure now exerted on collar 3 in the direction of arrow 1 becomes larger than the elastic resistance opposed by spring 16. At this moment slider 4 is diplaced in the direction of arrow under the effect of this pressure. In this regard it is to be observed that the pressure which is present at the end of 9 of the bore can no longer have any effect on the slide plug 10 and on the movable carriage because the latter is in an abutting position. I

During the course of its displacement the slider closes the opening of the output canal 6 and the opening of the return canal 7a. However, spring 16 itself assures in that case in a dependable manner the final displacement until the cross-braces 21 come to bear against plate 13 of the movable carriage.

The slider is now in a position which is sufiicient to assure the reversal of the feeding operation. In fact, the opening of the output canal 6a is opened only partly, by the dimension a and the same is true for the opening of the return canal 7. But as a whole, during the course of a first displacement, the piston has travelled a distance b and according to an important feature of the invention the dimensions and the disposition of the different elements are such that the dimension a is smaller than half the dimension b.

In this connection it will be observed that during the first portion of this displacement the movement is carried out under the effect of the pressure acting against collar 3, and against the effect of spring 16. But from the center of the displacement distance b, thus before and opening of the orifices of canals 7 and 6a. takes place, the curvature of this spring is to some extent reversed, so that it exerts henceforth a biasing action on the slider in the reversed direction, thus a positive effect in the direction 1 of the displacement. Under these conditions the last por tion of this displacement, which corresponds to the dimension a and consequently to the partial opening of the orifices of canals 7 and 6a is carried out while spring 16 exerts already a positive action on the slider. Thus, from the fact that the force accumulated to some extent by the spring during the initial portion of this displacement, the action of the latter achieves in a certain manner this displacement by partially opening the orifices of the canals 7 and 6a. It will be noted that in this position (FIG- URE 3) the collar 3a has just closed the orifice of the return canal 7a of the branch line leading to the reservoir. Due to this fact the displacement of the slider into this position will not be impeded by a backpressure in the fluid which is repulsed at the end 9a of the bore 2.

However, from this moment on the line communicating with canal 6a is supplied with lubricant while the other line is connected to discharge. This results in a certain pressure at the extremity 9a of the bore 2. In view of the fact that the surface of plug 10a is larger with respect to the surface of collar 3a this pressure causes a displacement of this plug and subsequently of the movable carriage also in thedirection of arrow f. This movement is stopped as soon as plate 13 of the movable carriage comes to rest against housing 1.

It is understood that the movable carriage takes along the slider 4 during its displacement because the extremity 11 of the latter is connected to the movable carriage by spring 16. The piston effects thus a new displacement 0 equal to the displacement of the carriage (see FIGURE 4). This movement terminates the reversing cycle of the device because thereafter the orifice of canal 6a is completely open as is the orifice of return canal 7 leading to the reservoir.

However, this second stroke of the first reversing cycle has the primary purpose of preparing to some extent the other movements of the elements for the following reversing cycle. In fact this second displacement assures the return to the right from the starting position of the slider during the first stroke of the second reversing cycle so that the displacement b of the slider during this first stroke may, as in the case of the first cycle, be greater than twice the dimension a of the opening of the orifices of the canals 7a and 6 at the end of this first stroke.

It is to be understood that the slider and the movable carriage remain in the position illustrated in FIGURE 4 during the feeding of the metering means of the branch line connected to canal 6a. When this feeding is completed and the pressure increases in this line, it produces the second reversing cycle which takes place exactly the same as the first cycle.

This pressure produces now a first displacement of the slider 4 in the opposite direction .of arrow 1 against the action of spring 16 while the movable carriage remains in place (see FIGURE 5). The slider has thus reached as in the earlier case a position which is sufiicient to assure the reversal, the orifices of canals 7a and 6 being partly open according to dimension a which is less than half the dimension of the total travel b of this first displacement. Thus as previously, the spring 16 exerts on the slider a positive motion in the direction of its displacement during the course of the first portion of this displacement so that it completes this displacement in a dependable manner.

However, from this moment on the pressure which exists at the end 9 causes the displacement of the movable carriage also in the opposite direction of arrow and consequently causes a second displacement of the slider in order to reach the position illustrated in FIGURE 1; This second displacement terminates the reversing operation but its primary role is to prepare for the firstdisplace: ment of the next reversing cycle by returning to the left side the next point of departure of the slider.

Under these conditions the device according to the invention operates thus in two strokes for each reversing cycle and its operation is carried out in a perfectly dependable manner without the necessity of providing complementary safety elements. In fact there is no risk that the slider may lock either in its center position or in one of its end positions. In this connection it may be noted that the displacement of the movable carriage which corresponds to the second stroke ofthe slider movement has in each instance as essential role the preparation to some extent for the next reversing cycle, so that a displacement of the slider in the course of the first stroke of the cycle may be carried out in a dependable manner. Furthermore during the course of the second stroke the fluid which is repulsed at the end of the bore toward which the displacement of the piston is directed after the corresp-onding return canal has closed, is to some extent absorbed by the concomitant displacement of the corresponding end plug which avoids also any risk of locking.

As already indicated above the present device has the advantage of being extremely economical, because its structure is very simple and it comprises only one bore of relatively short length and a single piston to be ground. Furthermore this device may be employed not only for providing a reversing action of a two-line central lubrieating system but also as automatic valve for a singleline system. In this case it is sufficient to close one of the output canals, for example canal 6a.

The operation is then as follows: In the end position illustrated in FIGURE 1 the device carries out the feeding of the single line connected to canal 6. When this feeding is completed and the pressure in this line increases the slider is caused to be displaced in two strokes as previously indicated in order to reach the position illustrated in FIGURE 4. In this position the single line is automatically set to discharge toward the reservoir due to its connection with the return canal 7. At this moment the displacement carried out by the slider or in some instances by the movable carriage may cause by suitable means the stopping of the operation of the pump, or control a signalling device so that it may be stopped by an operator. Subsequently, when the pump is again set to operation for example by a control device with a retarding action the pressure arrives in the canal 6a and in the extremity 9a of the bore. But as this canal is closed, this pressure causes immediately a displacement of the slider in the opposite direction.

Thus the single line previously set to discharge is again set to charge. This device may thus effectively replace the valves presently employed in single-line central lubricating systems, and in a more advantageous manner, because it operates automatically without requiring any observation.

It is clear that the device according to the invention is not limited to the one embodiment or construction which has been described above only as an example. Thus the spring 16 which consists of two curved blades which are able to maintain the slider in each of its end positions while contributing to completing each of its displacements, may be replaced by any other equivalent type of spring or spring mechanism for example a spring mechanism comprising a toggle joint arrangement. In the example illustrated the control spring of the slider has a predetermined resilient force. However, it is quite evident that it would also be possible to provide a variable force spring which would permit to modify selectively the pressure which determines the operation of the device.

What is claimed is:

1. A direction control valve for connecting a fluid pressure source alternatively with a respective fluid distribution conduit and for simultaneously connecting another of said conduits with a reservoir return line, said valve comprising: a valve body having a transverse bore which comprises an intermediate portion and opposite end portions, a distribution and a reservoir return canal for each said conduit, said canals extending into said body and opening into the'intermediate portion of said transverse bore at transversely spaced apart locations thereon, a spindle slidably mounted within said bore and including transversely spaced apart collar portions slidably mounted Within said intermediate portion, said collar portions being adapted to respectively close off or open respective ones of said canals relative to said bore, a supply canal for said fluid pressure source extending into said body and opening into said bore inter mediate portion between said distribution canals, a carriage assembly mounted on said body for limited sliding movement parallelly to" said spindle and comprising a respective end member at each opposite end of said. spindle, said end members being rigidly interconnected together, and each comprising a piston member slidably mounted in each said bore end portions, each said piston member having an inner radial surface respectively facing an opposed corresponding surface on.

said collar portions, the area of the piston radial surface being greater than that of the opposed collar portion surface, said pistons being slidable in said bore relative to said spindle, conduit means in said body respectively connecting said distribution canals with said bore end portions between said piston members and said collar portions, means connecting said carriage assembly to said spindle and permitting limited transverse sliding of said spindle relative to said assembly, said spindle and said assembly each being actuable to slide in said bore in response to a fluid pressure differential between said distribution canals, the transverse distance between said distribtuion canals and between said reservoir return canals being such that said collar portions close off the distribution canal and the reservoir return canal corresponding to different ones of said distribution conduits while simultaneously uncovering the respective other distribution and reservoir return canals.

2. The direction control valve of claim 1, wherein said reservoir return canals are respectively closed off from or open to respective ones of said bore end portions in correspondence to said return canals being covered or uncovered by said collar portions.

3. The direction control valve of claim 2, wherein said connecting means comprises transversely spaced apart abutment means on said carriage assembly, said spindle being transversely slidable relative to said assembly to an extent limited by said abutment means.

4. The direction control valve of claim 3, wherein said connecting means comprises an over-center spring device Which biases said spindle towards either of said abutment means in correspondence to said spindle being on either side of a central transverse position relative to said carriage assembly.

5. The direction controlvalve of claim 4, said spindle being slidable between first and second opposite transverse positions relative to said carriage assembly with said assembly being at either of opposite transverse positions relative to said body, with said spindle being in said first position a one of said distribution canals being open to said supply canal and the other of said distribution canals being closed oil from said supply canal and open to its corresponding reservoir return canal, with said spindle being in said second position said one canal being closed otf from said supply canal and partially open to its corresponding reservoir return canal and said other distribution canal being equally partially open to said supply canal and closed oif from its corresponding reservoir return canal, the amount of opening of said one and other canals being less than half the transverse distance between said first and second positions.

6. The direction control valve of claim 5, said spindle being further slidable together with said carriage assembly to further uncover said one and other canals.

7. A direction control valve for selecting two alternative flow and return fluid paths, said valve being of the five-way, closed center type and actuable by the difference of pressures between said paths, comprising in combination: a valve body having two canals for the alternative selected paths; a spindle having lands and disposed in said body to be actuated by the difference of pressure at said canals; a carriage mounted coaXi-ally with said spindle, and constituted by two pistons, solid in translation one with the other and disposed on either end of the spindle respectively to be actuated by the difference of pressure'at said canals; the diameter of said pistons being greater than the diameter of said lands; whereby said spindle is actuated by said carriage after the cross-over position when said spindle moves across center.

References Cited by the Examiner UNITED STATES PATENTS 2,743,738 5/1956 Johnson 251-75 X FOREIGN PATENTS 1,151,669 8/1957 France,

1,160,216 2/1958 France.

1,241,171 8/1960 France.

LAVERNE D. GEIGER, Primary Examiner.

20 H. BELL, Assistant Examiner.

Claims (1)

1. 7. A DIRECTION CONTROL VALVE FOR SELECTING TWO ALTERNATIVE FLOW AND RETURN FLUID PATHS, SAID VALVE BEING OF THE FIVE-WAY, CLOSED CENTER TYPE AND ACTUABLE BY THE DIFFERENCE OF PRESSURES BETWEEN SAID PATHS, COMPRISING IN COMBINATION: A VALVE BODY HAVING TWO CANALS FOR THE ALTERNATIVE SELECTED PATHS; A SPINDLE HAVING LANDS AND DISPOSED IN SAID BODY TO BE ACTUATED BY THE DIFFERENCE OF PRESSURE AT SAID CANALS; A CARRIAGE MOUNTED COAXIALLY WITH SAID SPINDLE, AND CONSTITUTED BY TWO PISTONS, SOLID IN TRANSLATION ONE WITH THE OTHER AND DISPOSED ON EITHER END OF THE SPINDLE RESPECTIVELY TO BE ACTUATED BY THE DIFFERENCE OF PRESSURE AT SAID CANALS; THE DIAMETER OF SAID PISTONS BEING GREATER THAN THE DIAMETER OF SAID LANDS; WHEREBY SAID SPINDLE IS ACTUATED BY SAID CARRIAGE AFTER THE CROSS-OVER POSITION WHEN SAID SPINDLE MOVES ACROSS CENTER.

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