US2145547A - Hydraulic control mechanism - Google Patents

Description

Jan. 3l, 1939. H. W. LANDENBERGER M5547 HYDRAULIC CONTROL MECHANISM Filed March 26, 1935 2 SheetS--Sheeii l AUXILIAR), FUN P .n-l-A llllllulnlllllllgmn Jan. 31, 1939. H. w. LANDENBERGER 2,145,547

HYDHAULI C CONTROL MECHANI SM Filed March 26, 1935 2 sheets-sht 2 Patented Jan. 31, 1939 UNITED STATES HYDRAULIC CONTROL MECHANISM Henry W. Landenberger,Philadelphia, Pa., as-

signer to American Engineering Company,

Philadelphia, Pa., a vania corporation `oir' Pennsyl- ApplicatonMarch 26, 1935, Serial o. 13,095

d Claims.

This invention relates to control mechanisms for pumps, and more particularly Ato control mechanisms of the hydraulic type.

l One object of the present invention is to pro- .vide a generally improved control mechanism for pumps which is entirely hydraulic in form.

Another object is'to provide a control mechanism for pumps employed in the operation of hydraulic presses and like machines, which funclO tions to maintain the pump on stroke until a predetermined pressure is exceeded whereupon the pump is automatically adjusted to neutral position.

A further object is to provide a control mechal5 nism for pumps employed for operating presses and like machines, which functions in such a manner that when the' press platen completes I its cycle of operation 'the pump will be adjusted to neutral stroke position and retained in this position at a relatively low pressure.

Other and further obj ects will become apparent as the description of the invention progresses.

Of the drawings: Fig. 1 is a diagrammaticview partly in section showing the control mechanism comprising the present invention.

Fig. 2 is a side elevational view partly in section of the pump and some of the control elements associated therewith.

Fig. 3 is a side elevational view of the pum and control elements shown in Fig. 2.

Referring to the drawings, the numeral l desig-` nates generally a pump, mounted upon a supply or makeup tank 2. Pump l may be of the general type shown and described in the United States Patent to Hele-Shaw No. 1,077,979, which in the present instance is so constructed as to deliver iluid under pressure to pipe 3 and suction to pipe d. Pipe 3 is operatively connected to a port ii o provided in the lower side of a control valve 6. Control valve 6 comprisesa reciprocable valve element i having a pair of spaced valve heads and l adapted for adjustment by a lever l@ to selectively establish communication between pipe Li5 3 anda pair of pipes il and l2. Pipe il, together with a branch pipe i3, delivers fluid to a pair of lpullback motors lll and l5 of a hydraulic press i5. Pipev l2, on the other hand, communicates with the upper end of a -cylinder ll having a piston ld operating therein which has secured theretd a`. connecting rod lil operatively connected to amovable platen 2B of the hydraulic press i6. 'lheconnecting rods 2| and 22 connected to vpistons and 2d' of pullback motors M and l5 respectively are also operatively connected to platen 20, as shown in Fig. 1. It therefore is seen that when lever lll is in the full line position shown in Fig. 1, fluid from pump IV will discharge through pipes i l and I 3 and thereby cause platen 20 to move toward its upper position. On the other hand, when lever I0 is moved to the dotted line position iiuid will enter cylinder l'l and thereby cause the platen to move downwardly towar the work.

Valve 6 has also provided therein a passage 25 which communicates with the opposite ends of the chamber in which the valve member 'l operates. Passage 25 also communicates with a pipe 2B to which the suction pipe ll leading from pump l is connected. A check valve 2 is secured to the extreme right hand end (Fig. 1) of pipe 26, and a second pipe 26' connects said valve with makeup tank 2. Check valve 2l prevents the .iluid returning to pump l through pipes'26 and l .from flowing to the makeup tank 2 but permits makeup fluid to be drawn into the system' in a well known manner. The drive shaft 28 of pump l is connected to the armature shaft 29 of an electric motor or any other suitable driving mechanism (not shown) by a coupler 30.

The pressure required to operate certain of the control elements associated with pump l is derived from a small auxiliary pump 3|, which, as shown in Fig. 1, is connected to the drive shaft 28 by a chain and sprocket mechanism 32. Pump 3l discharges uid under pressure through, a pipe33 which is connected to a. branch pipe 3d. The pressure developed by pump 3l is controlled by an adjustable relief valve l0 provided in a bypass pipe 7H which connects pipe 33 with makeup tank 2. One end of pipe 34 is connected to a fluid motor 35 mounted at the right hand side of pump l while the other end of said pipe is con- Y nected to a port 36 of a valve 3l, mounted n ear the upper end'of press iii in any suitable manner.

Referring more particularly to Figs. 2 and 3, it

will be seen that pipe 34 is so `connected to motor 35 that iiuid is delivered to the left hand side of the piston 38 thereof.

right hand side of casing 39 of pump l in any suitable manner, such as by rods tl). y

Motor 35 is secured to the A Al-"iston 38 has -secured thereto a rod M which justing elements 45 of the pump in a well known manner.

'I'he right hand end of motor 35 has secured thereto one end of a second pipe 46, the other end of which is connected to a second port 41 of valve 31. Valve 31 has provided therein a reciprocable valve member 48 having a pair of valve heads 49 and 50. A spring 5| mounted in a'casing 52 at the upper end of valve 31 extends between the upper end of said casing and 'a ldisc 53 secured to the upper end of a rod 54, the lower end of said rod abutting the upper end of valve member 48. The lower end of valve member 48 has secured thereto a rod or stem 55 extending through an aperture provided in the lower end of valve casing 31 and is adapted to be engaged by platen 20 when the latter approaches the limit of its upward movement. Fig. 1 shows the arrangement of the parts when the platen 28 is out of engagement with rod 55, at which time it will be observed thatspring 5| has urged. valve member 48 downwardly so that valve heads 49v and 58 prevent communication between pipes 34 and- 46. Valve 31 has also provided therein a substantially vertical passage 12 whichv connects the upper and lower ends of the valve chamber and communicates with ',a'port 13. A pipe 14 secured -to and extending between port 13 and makeup tank 2 connects valve 31 to exhaust. When the parts are in this position, the uid discharging i'rom pump 3| is trapped between these valve heads and asa result fluid pressure isdelivered.k only to the left hand side of piston 38. However, when platen 20 moves upwardly valve member 48 will also be moved upwardly, thereby establishing communication between pipes 34 and 46 and as a result fluid discharging from pump 3| will enter motor 35 through pipes 34 and 46,

thereby subjecting both ends of the piston 38 to fluidppressure. Inasmuch as the effective area of the righ't hand end of piston 38 is greater than that ,of the left hand endthereof, due to the connection thereto of the connecting rod 4|, pis- -stroke position. During movement of piston 38 in this manner the fluid in the chamber at the right hand side thereof will now flow through pipe 46, valve 31, port 13, pipe 14, and thence into makeup tank 2.

Pump I has also secured to the left hand side thereof, such as by bolts 51, or any other suitable securingmeans, a second fluid motor 58. This motor also comprises a cylinder 59 having a piston 60 operating therein. The right hand end of cylinder 60 communicates with a substantially vertical passage 6| extending upwardly from the lower end of the casing and to which one end of a pipe 62 is connected. The other end of pipe 621s connected to the pressure pipe 3 leading from pump It therefore is seen that motor 58 israt all times connected to the pressure delivered` by pump I. Piston 68 extends through a gland 63 provided at the left hand end of motor 58 and abuts against the right hand side of a cross-l head 64. Crosshead 84 has secured to the opposite ends thereof a pair of guide rods 65, the inner ends of which pass through suitable bearings provided in the left hand side of pump casing 39, and are also secured to the sliding blocks 45, as shown more particularly in Fig. 1. Secured to the opposite ends of a flange 66 of motor 58 are a pair of threaded rods 61. apertures provided in Crosshead 64 and have a pair of adjusting nuts 68 secured to the left hand ends thereof. By this construction, it is seen, the extent of movement to the left of the sliding blocks or stroke adjusting elements 45 may be varied to best suit the conditions of operation.

From the foregoing description, the operation of my improved control mechanism is thought to be obvious. However, in Vorder to correlate the various elements thereof, a brief rsum of the operation of the device as a whole will now be given.

Let us assume that the platen 28 is in its uppermost position and that it is desired to begina new cycle of operation. The operator rst grasps lever I and moves the same to the dotted line position shown in Fig. 1. The fluid trapped in pullback motors I4 and I5 will noI flow through pipes |3 and passage 25, pipe 26, and pipe 4 to pump I, and platen 20 will gravitate out of engagement with valve stem 55. When this occurs spring will urge valve member 48 to the position shown in Fig. 1.. Fluid discharged from pump 3| will now actua-te piston 38 and the stroke adjusting means 45 of pump I to on-stroke position and as a result fluid under pressure from pump I will be delivered to cylinder I1, thereby actuating platen 20 toward the work. As the platen engages the work, the pressure in the system gradually increases and when this pressure exceeds the value determined by the relative sizes of the left hand side of piston 38 operated upon by pump 3|, and piston 68 operated upon by the pressure in the system as developed by pump I, the sliding blocks or stroke adjustingL elements 45 of pump I will move to the left toward neutral or leakage stroke position. The iluid at the left hand side of piston 38 will now flow through pipes 34, 33 and 1I, relief valve 10, and thence into makeup tank 2. The required predetermined pressure may thus be maintained upon the work as long as desired.

When it is desired to remove the material from the press after a pressing-operation, the opera- These rods pass through tor simply moves the lever I0 to the full line position shown in Fig. 1. This causes a reduction of the pressure in the system and the fluid from pump 3| will now actuate piston 38 to the right to place pump onstroke. Fluid from pump I will nowenter pipes I I and I3, causing platen 20 to be moved upwardly by the operation of pullback motors |4l and |5. The fluid in cylinder |1 will now be forced back through pipe .|2, passage 25 of valve 6, and thence to pump |`through pipes 26 and 4 respectively. As the platen 20 approaches its upper limit of travel it engages valve stem 55, thereby moving valve member 48 upwardly and establishing communication between pipes 34 and 46, and as a result fluid pressure from pump 3| will be delivered to both ends of piston 38. Due to the fac-t that the right hand end of piston 38 has a ugreater effective area than the left Vhand end thereof, and also due to the operation of motor 58, as well as the natural tendency of the pump to assume a neutral position, the sliding blocks or stroke adjusting elements 45 will move. to the left toward neutral position. The platen 20 of the press I6 will now be held in its uppermost be the case in the event these 'areas were unequal.

It thereforeis seen that a simple and' highly eilicient control mechanism has been provided. After each cycle of operation the platen is held in its uppermost position at a relatively low pressure, and consequently a great saving in the power necessary to operate the pump is effected.

While the embodiment herein shown is admirably adapted to -fulfill the objects primarily stated, it is to be understood that the invention is not to be limited to this embodiment, since it may be embodied in other forms, all coming within the scope of the claims which follow.

What is claimed is:

1. In a device of the class described, the combination o; a variable discharge pump, stroke adjusting -felements for said pump, means for actuating-.said stroke adjusting elements to different positions of adjustment, said means comprising a cylinder having a piston operating therein, a rod operatively connecting said piston to said stroke adjusting elements, an auxiliary pump constantly connected to the connecting rod end of said cylinder, an adjustable control valve, iiuid conducting means connecting said auxiliary pump to said valve, fluid conducting means connecting said valve to the head end of said cylinder, means for so adjusting said valve that fluid from said auxiliary pump flows to the head end of said cylinder, whereby the said piston operating therein actuates said stroke adjusting elements toward neutral position, means for disabling said last mentioned means, and means for adjusting said valve to a second position of adjustment to disconnect said auxiliary pump from the head end of saidv cylinder and to connect the latter' to exhaust, whereby the pressure from said auxiliary pump acting on the connecting rod end of said piston eects actuation of said stroke adjusting elements'in the reverse direction to increase the discharge of said variable discharge pump.

2. In a device of the class described, the combination' with a fluid motor, of a variable stroke pump for actuating said motor, stroke adjusting elements for said pump; means for actuating said stroke adjusting elements to diierent positions of adjustment, 'said means comprising a cylinder having a piston operating therein, a rod connecting said piston to said stroke adjusting elements, an auxiliary pump constantly connected to the connecting rod end of said cylinder, an adjustable control valve, iuid conducting means connecting said auxiliary pump to said valve, uid conducting means connecting said valve to the head end oi said cylinder, means actuated by said motor when approaching its normal position for so adjusting said valve that iiuid from said auxiliary pump flows to the head of said cylinder whereby the said piston operating therein actuates said stroke adjusting elements toward' neutral position, means for actuating said iluid motor in the reverse direction, whereby the said means actuated thereby is moved out of operative relation with said valve, means for adjusting said valve to a second position oi adjustment to disconnect said auxiliary pump from the head end of said cylinder 'and to connect the latter to exhaust, whereby the pressure from said auxiliary pump acting on the connectingrod end of said piston effects actuation of said stroke adjusting elements in the reverse direction to increase the discharge of said variable discharge pump.

3. In a device of the class described, the combination with a fluid motor, of a variable stroke pump for actuating said fluid motor, a reversing valve for controlling the operation of said fluid motor, stroke adjusting elements for said pump, means for actuating said stroke adjusting elements to diierent positions of`adjustment, said means comprising a servo motor operatively connected to said stroke adjusting elements, said servo motor having a piston operating therein,

the opposite ends of said piston being of unequal areas, an auxiliary pump constantly subjecting the end of said piston of smaller area to pressure, an adjustable control valve, fluid conducting means connecting said auxiliary pump to said valve, fluid conducting means connecting said valve to the end of the cylinder adjacent the larger end of said piston, abutment means actuated by said iiuid motor adapted to so adjust said valve when said fluid motor approaches its normal position of adjustment, that iiuid from said auxiliary pump flows to the end of said piston of larger area, whereby the latter actuates said stroke adjusting elements toward neutral position, said abutment member moving out of 4engagement with said control valve upon movement of said uid motor in the reverse direction, means functioning to adjust said valve to a second position of adjustment to disconnect said auxiliary pump from the end of said piston of larger area and to connect the latter to exhaust, wheres by the uid pressure in said auxiliary pump acting on the end of said piston oi smaller area eifects actuation of said stroke adjusting elements in the reverse direction to increase the discharge of said variable discharge pump.

4. In a device of the class described, the combination vwith an hydraulic press, having a movable platen, of a variable stroke pump for actuating said platen, stroke adjusting elements for said pump, means for actuating said stroke adjustton operating therein, a rod operatively connect-4 ing one end of said pistonto said stroke adjusting elements, an auxiliary pump constantly connected to the connecting rod end of said cylinder, an adjustable control valve, fluid conducting means connecting said auxiliary pump to said valve, fluid conducting means connecting said valve to the head end of said cylinder, means actuated by said platen when approaching its normal position for so adjusting said valve that iiuid from said auxiliary pump flows to the head end of said cylinder whereby the saidV piston operating therein actuates said stroke 'adjusting elements toward neutral position, means for actuating said platen in the reverse direction whereby the latter is moved out of engagement with said valve, means for adjusting said valve to a second position of adjustment to disconnect said auxiliary pump from the head end of said cylinder and to connect the latter to exhaust,` whereby the pressure from said auxiliary pump acting on the connecting rod end of said piston eiects actuation of said stroke adjusting elements in the reverse direction to increase the discharge of said variable discharge pump.

MNRY W. LANDENBERGER.

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