US2553810A - Fluid control device - Google Patents

Description

May 22, 1951 M. CARLSON FLUID CONTROL DEVICE Filed Dec. 9, 1948 45 63 INVENTOR.

m I i tin Carlson mar ' control be fully automatic.

Patented May 22, 1951 FLUID CONTROL DEVICE Martin Carlson, Brookfield, 111;, assignor to- George W. Houlsby, Jr.; Chicago, Ill.

Application December 9, 1948 Serial No. 64,383

- 4 Claims.

My invention relates to control systems. It relates more in particular to a fluid control combination utilizable in installations of a type in which a piston or the like should have a relatively rapid initial movement and a retarded final movement.

In fluid control devices, of which the Door Check Mechanism disclosed in my copending application Serial No. 20,515, filed April 12, 1948, is illustrative, it is desirable that the movement of the hydraulic piston be relatively rapid during the first part of its movement and relatively retarded during the final portion of its movement. It is also desirable that the necessary Another example of a system in which the same general type of control is desirable is a hydraulic lifting jack in which fluid is pumped into a cylinder to move a piston during the lifting operation and released from the cylinder during the lowering operation. In the use of such jacks, it is the practice to control the hydraulic fluid by hand; but such control is frequently entirely unsatisfactory. I am aware that means for the automatic control of fluid flow in such devices has been suggested, but in general it has involved the control of the area of an orifice and it is well known that such control is accomplished only with great difliculty and frequently the results are unsuccessful. I

The principal object of m invention is the provision of an improved control of the character identified. Still another object is the provision of a fluid control device which may be associated with any working piston of the type usually in hydraulic systems.

The drawings show one specific embodiment of my invention in which Fig. 1 is a fragmentary sectional view of a piston through a portion of a cylinder and piston showing the piston in an expanded position;

Fig. 2 is a similar view showing the piston advanced substantially its maximum distance within the cylinder;

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 1 looking in the direction of the arrows;

Fig. 4 is a fragmentary enlarged sectional view taken through a portion of the valve comprising my invention; and

Fig. 5 is a sectional view showing a modified structure in which adjustment of the point of complete cut-off of one outlet port is possible.

In Figs. 1 to5, inclusive, I have shown the invention in relatively simple form associated with a Cylinder I0 and IJiStbn ll reciprocable' therein. The Cylinder head is provided with a fluid intake l2 and a pair of outlet passageways v I3 and I4. Passageways [3' and [4' are con--* from the passageways l3 and reservoir.

the'passageways l3 and M and are adjustable nec'ted at 16 and a discharge passageway I! is provided from the said cross passageway l'6'. This is illustrative of a simple arrangement, but obviously the fluid discharge could be directly Hi to a single Tapered plugs I8 and 19 project into to control the cross-sectional area between the passageways l3 and 14 and the cross passage -way It, respectively. Thus, by controlling the positions of the plugs l8 and IS, the effective area of the two discharge controlled.

It will be recalled that my invention may be employed in a hydraulic system in which fluid is drawn into the cylinder l0 by the action of the piston, or in which the piston H may be raised against a load by forcing hydraulic fluid into the cylinder beneath the piston. It is without significance so far as my invention is concerned, therefore, whether the inlet I2 is connected to a pump system for receiving fluid under pressure or to a static sump system in which fluid is merely made available for delivery on the suction stroke of the piston. In any case,

the inlet passageway is provided with a seat 21 the ball 22 is held against its seat and ejection of fluid through the inlet passageway is prevented. The fluid is, therefore, forced to pass only through the outlet passageways 'I3 and [4* and hence its flow may be controlled.

Disposed centrally of the passageway I4 I provide a valve pin 24 having' a tapered end 26 and shoulder 21 adapted to fit snugly against a seat 28 formed at the upper edge of passageway l4. The pin 24 is carried by a guide 29 which is threaded in a bottom opening 3| in the piston, and has a head 32 engaged by a compression spring 33. The compression spring 33 holds the valve pin 24 at the bottommost position when the piston is in elevated position, but

can be compressed as indicated in Fig. 2 when shoulder 21 engages the seat 28. Preferably the valve pin 24 is supported axially of the piston I I so that even though the piston may be rotated slightly, the tapered portionifi willalways be in alignment with the passageway l4.

passageways may be The operation of the device is as follows. When the piston is in elevated position and the cylinder below the piston is filled with fluid either by suction or under pressure, as in a hydraulic jack or like device, the valve pin 24 is at its lowermost position as shown in Fig. 1. When the piston moves downwardly under load, hydraulic fluid will pass through both passageways !3 and I4 in total amount determined by the cross-sectional area of such passageways, or, when adjustable means 18 and 19 are employed, by the position to which such means has been adjusted. As the piston moves downwardly, the passageway 14 is first gradually restricted through the entrance of the tapered portion 26, and of course this tapered portion can be shaped in any desired manner to provide as much of a gradual restricting of the fiow as desired. When the valve pin has been seated entirely with the shoulder 21 on the seat 28, however, passage of fluid through the passageway I4 is substantially completely arrested. At this time, however, the piston is still permitted to descend because the spring 33 may be compressed, but the flow of fluid from the cylinder will be greatly decreased because it is passing only through the passageway l3. In this manner, by properly designing the parts, almost any type of control and deceleration which could possibly be required may be provided for. It will be understood also that by providing more than one valve pin 24, operating at different times in a cycle, deceleration can be further expanded as desired.

. In the modified form shown in Fig. 5, the cylinder 36 has a piston 31 reciprocable therein, and is provided with an inlet passageway 38 and outlet passageways 39 and il generaly similar to those provided in the first described embodiment. The outlet passageway 4i, however, is disposed in an adjustably positioned plug 42 and has radial ports 43 communicating with annular recess 44 which is generally in alignment with passageway 46. Passageway 46 connects with passageway 41 in which a tapered plug 48 isadjustable. A similar tapered plug 49 is disposed in the outlet passageway 38 so that by the adjustment of the tapered plugs 48 and 49 the effect of cross-sectional area of the two outlet passageways can be varied. A cross passageway interconnects the outlet passageway 39 and the passageway 41, and a discharge passageway 52, corresponding generally to the discharge passageway I! previously described, leads from the cross passageway 5|.

The piston 31 carries a tapered valve pin 53 which is reciprocable in guide 54 and has a head 56 engaged by spring 51. The pin 53 has a tapered end 58 which extends into the outlet passageway 4i and a shoulder 59 adapted to fit against a seat 6| to substantially completely close the passageway 4|.

The device, as shown in Fig. 5, functions substantially the same as the previously described device except that the position at which the tapered end of the pin begins to close the passageway 4| and the position at which this passageway is substantially completely closed off is made adjustable by turning the plug 42. Suitable means is utilized to prevent leakage of fluid past the plug 42 and I have found that a small ring 62 of neoprene or other synthetic rubber or like material resistant to attack by oils and greases may be used. All that is necessary is to provide an annular groove on the exterior of the plug and engagev the ring 62 therein, the parts 4' being so arranged that there is some slight compression of the ring 62 when assembly has been completed. In functioning as an inlet, the passageway 38 may be suitably provided with a ball check 63 and usual means referred to hereinabove for bringing hydraulic fluid into the cylinder and receiving discharge therefrom may, of course, be used.

I have described my invention in simple form and in detail for the guidance of those skilled in the art; it is understood that the invention is defined by the scope of the claims.

What I claim as new and desire to protect by Letters Patent of the United States is:

1. A hydraulic check mechanism comprising means forming a cylinder with an end wall, a piston fitted to said cylinder, said end wall having an opening therethrough forming an inlet to said cylinder, means forming a one Way check valve in said opening to prevent outward flow therethrough, said end wall having a second opening therein coaxial with said cylinder with the inner end of said opening forming a valve seat, said piston having a cavity formed in the end thereof in alignment with said valve seat, a valve pin disposed partially within said cavity with the end projecting therefrom, said end being tapered to a point and having an abrupt annular shoulder at the large end of said taper, said large end being smaller than said valve seat and said shoulder being large enough to close said second opening at said seat, means for retaining said pin in said cavity while permitting limited axial movement thereof, resilient means aid cavity for urging said pin to its outward limit, athird opening in said end wall, said second and third openings being connected by a transverse passage Within said end wall, an outlet passage leading from said connected second and third openings, adjustable valve means fitted to the outer end of said second passage and adjustable to control the flow rate between said second passage and said transverse passage and similar adjustable valve means fitted to the outer end of said third passage and adjustable to control the flow rate between said third passage and said transverse passage.

2. A hydraulic check mechanism comprising means forming a cylinder with an end wall, a piston fitted to said cylinder, said end wall having an opening therethrough forming an inlet to said cylinder, means forming a one way check valve in said opening to prevent outward flow therethrough, said end wall having a second opening therein coaxial with said cylinder, a valve seat forming member threaded into said second opening with said seat facing inward, said piston having a cavity formed in the end thereof in alignment with said valve seat, a valve pin disposed partially within said cavity with the end projecting therefrom, said end being gradually tapered to a point and having an abrupt annular shoulder at the large end of said taper, said large end being smaller than said valve seat and said shoulder being large enough to close said second opening at said seat, means for retaining said pin in said cavity while permitting limited axial movement thereof, resilient means in said cavity for urging said pin to its outward limit, a third opening in said end wall, said second and third openings being connected by a transverse passage within said end wall, an outlet passage leading from said connected second and third openings,

ladjustable valve means fitted to the outer end of said second passage and adjustable to control the flow rate between said second passage and said transverse passage and similar adjustable valve means fitted to the outer end of said third passage and adjustable to control the flow rate between said third passage and said transverse passage.

3. A hydraulic check mechanism comprising means forming a cylinder with an end wall, a piston fitted to said cylinder, said end wall having an opening therethrough forming an inlet to said cylinder, means forming a one way check valve in said opening to prevent outward flow therethrough, said end wall having a second opening therein coaxial with said cylinder, a valve seat forming member threaded into said second opening with said seat facing inward, said piston having a cavity formed in the end thereof in alignment with said valve seat, a valve pin disposed partially within said cavity with the end projecting therefrom, said end being gradually tapered to a point and having an abrupt annular shoulder at the large end of said taper, said large end being smaller than said valve seat and said shoulder being large enough to close said second opening at said seat, means for retaining said pin in said cavity while permitting limited axial movement thereof, resilient means in said cavity for urging said pin to its outward limit, an outlet passage leading from said second opening, adjustable valve means to control the flow rate through said second opening, and means accessible from outside said cylinder for rotating said seat forming member to determine the position of said piston at which said valve pin enters said seat forming member.

4. In a hydraulic check device, means forming a dash pot cylinder and piston combination, said combination having an inlet opening of suflicient size to permit substantially uninhibited inflow of hydraulic fluid into said cylinder when said combination is expanded, said inlet having a check valve to prevent outflow therethrough, means forming an outflow passage leading from said cylinder, said passage having an adjustable valve therein to limit the rate of fluid flow therethrough to cause slow but uniform rate collapsing of said combination near the collapsed end of its stroke, a second outflow passage, valve means for adjusting the flow rate through said second passage so as to permit rapid but controlled collapsing movement of said combination when said combination is near the expanded end of its stroke, a gradually tapered valve pin adapted to approach, enter and finally seal said second passage as said combination collapses so as to give a slow transition in the collapsing rate from said rapid to said slow but uniform rate, said valve pin having a gradually tapered end portion with an abrupt annular seating surface at the inner end thereof, saidtapered portion being smaller at all diameters than said second passage and said seating surface being larger than said second passage, and resilient mounting means for said valve pin to permit continued collapsing movement of said combination after said annular surface is seated in said second passage.

MARTIN CARLSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,891,312 Knecht Dec. 20, 1932 2,163,440 Tomkins June 30, 1939 FOREIGN PATENTS Number Country Date 361,122 Great Britain Nov. 19, 1931 478,566 Germany July 5, 1929

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