US2009851A - Fluid control mechanism - Google Patents

Description

July 30, 1935. H. w. LINK FLUID CONTROL MECHANISM Filed Oct. 28, 1933 2 Sheets-Sheet 1 Flay-Z 23 5 H H 7 I! I 77 /0 y! a 80 7.2

znvenzor July 30, 1935. w, LINK I 2,009,851

FLUID CONTROL' MECHANISM Filed Oct. 28, 1955 2 Sheets-Sheet 2 &

mp m 1 my W M J5 50 Znven 507* Harry W Link A Zforvzc y Patented July 30, 1935 UNITED STATES PATENT orl-"lcsig mesne assignments, to American Engineering Company, Philadelphia, Pa., a corporation of Pennsylvania Application October 28, 1933, Serial No. 695,602

9 Claims. (Cl. 103-38) This invention relates to fluid control mechanisms, and more particularly to fluid control mechanisms for pumps of the variable stroke reversible discharge type.

One object of the present invention is to provide a control mechanism including power means for adjusting the stroke of a pump of the stated character in either direction, and retaining the pump in adjusted position until the pressure delivered thereby exceeds a predetermined value, at which time automatic means functions to render said power means ineffective thereby permitting'the pump to assume a neutral position.

Another object is to provide a control mechanism for pumps of the stated character involving a fluid motor for adjusting and holding the pump on stroke, and automatic means associated with said motor and connected to the pres sure delivered by said pump which functions when the pressure exceeds a predetermined value to bypass the fluid of said motor thereby rendering the motor ineffective.

A more specific object is to provide a control mechanism of the stated character for fluid systems including a fluid motor and a pump for operating the same, and having manual means associated with the pump for placing thesame on stroke in either direction, and a followup mechanism for adjusting the pump to neutral when the motor has been operated a predetermined amount, and automatic bypass means associated with said motor for rendering the latter ineffective, when the. pressure in the system exceeds a predetermined value.

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

Of the drawings:

Fig. lis a plan View of a pump and motor unit showing the control mechanism for the v tie valve constituting one of the elements of the control mechanism.

Referring to the drawings, numeral l indicates generally a. pump and motor unit. comprising a variable stroke reversible discharge pump 2,

. driven by an electric motor :3. Pump 2 is of the general type shown and described in the United States Patent No. 1,077,979 to which reference may be had for a full disclosure'thereof. w

In the present instance the pump 2 is ema ployed for actuating an hydraulic press 4 including a cylinder 5 havinga ram 6 operating therein. The ram 6 is operatively associated with a mold 1 into which the material to be formed is placed. Fluid from pump 2111s conveyed to cyl-" inder 5 through pipes 8 and 9, respectively, the former of whichcommunicates with the upper end of cylinder 5 while the latter communicates with the lower end of said cylinder. Thus, when pump 2 is so adjusted as to discharge fluid under pressure through pipe 8, ram 6 -is forced down-' wardly and the fluid in the annular chamber between piston 6 and cylinder 5 is returned tothe' pump through pipe 9. It also follows that when the discharge of pump 2 is reversed fluid under pressure will enter the cylinder 5 of the hydraulic press 4 through the pipe 9 and suction will be applied at the upper end causing the fluid to return to the pump through pipe 8, and the fluid acting against the enlarged portion. ll) of end thereof which acts as a stop for the ram 6.: when thelatter has been moved to its upper limiting position.

The control mechanism comprising the present: invention is designated generally 'by the numeraland 3, a lever I8 is pivoted atone end to a bracket' l9 extending laterally from pump l6; Lever IB'is guided for movement between the upper edgetill of framework H anda cover plate, 2], and its movement ineither direction is limited by apair of stops 22 and 23 mounted in the flanges 25 and- 25 respectively, .of framework; I1. I A rod 26 is pivoted .to lever l8 intermediate the ends of the latter, and extends through a pairof-guideblocks The free end of rod 26 is pivoted to a link;29 intermediate:

27 and 28 securedto framework-l1.

the ends of the latter as shown in Fig. 1. Loosely mounted on rod 26, and abutting the inner face of guide block 21, is a spring seat 39. A similar spring seat 3| is also loosely mounted on rod 26 and which abuts against the inner face of guide block 28, and a coil spring 32 extends between these spring seats. Enlarged portions 33 and 34 extend through guide blocks 21 and 28 and the inner ends thereof abut against spring seats 3|] and 3| respectively. Thus spring 32 is compressed when lever |8 is swung in either direction. Spring 32 is provided for the purpose of centering lever I8, as will appear more fully hereinafter. The lower end of link 29 is pivoted to one end of a link 35, the other end of which is pivoted to the stroke adjusting mechanism 36 of pump I6. The upper end of link 29 is pivoted to one end of a link 31, the other end of which is pivoted to a crosshead 38 of motor |4. Motor l4, as shown more particularly in Fig. 5, comprises a main body portion 39 having a series of cylindrical bores 40, 4| and 42 provided therein for receiving pistons 43, 44 and 45 respectively, the cross sectional area of piston 44 being sub stantially equal to the combined cross sectional areas of pistons 43 and 45. Pistons 43 and 45 engage a crosshead 46, while piston 44 engages a crosshead 38, as shown in Fig. 5. Crossheads 38 and 46 are connected by a pair of tie rods 41 and 3 48 guided for reciprocation in cylinder body 39.

Cylinders 40 and 42 are connected by means of a passage 49 provided in casing 39 as shown in Figs. 4-and 5. Cylinder 42 is connected to pump l6 by means of a pipe 50, while cylinder 4| is likewise connected to pump |6 through a pipe connection It therefore is seen that when pump l6 has been adjusted so as to deliver pressure through pipe 50, fluid under pressure will enter cylinders 42 and 40, thereby actuating pistons 45 and 43 to the left (Fig. 5), causing crossheads 38 and 46 to move to the left, and likewise that when pump |6 has'been so adjusted as to deliver fluid pressure through pipe 5| piston 44 will be operated to the right, thereby causing crossheads 38 a and 46 to also move to the right.

Referring to Figs. 1 and 3, a substantially vertical lever 52 is pivotally connected at the upper end thereof "to a pairof links 53 which links in turn are pivotally connected to crosshead 46. The'lower end of lever 52 is pivoted to a bracket 54 secured to the casing of pump 2. One end of a link 55 is'pivoted to lever 52 intermediate the ends of the latter, the other end of which being pivotally connected to the stroke adjusting mechanism 56 of pump 2. It therefore-is seen that when pressure is applied to motor |4 through the pipe connection 50, pump 2 will be placed on stroke in 'one direction, and when fluid pressure is applied to the motor through pipe connection 5| pump 2 will be placed on stroke in the opposite direction.

Referring more particularly to Figs. 3 and 4, a second motor'51 is secured upon cylinder body 39 of motor l4 in any suitable manner. Also mounted upon cylinder body 39 and secured to motor 4 by tie rods 62 and 63 is a bypass valve housing 58, as shown in Fig. 4. Fluid motor 51 comprises a cylinder 59 having a piston 68 oper-- ating therein,'one end of which extends through a gland 6| provided at the inner end of said cylinder. As shown in Fig. 4, the valve stem 64 of a bypass valve 65 is secured at one end to piston 69. A crosshead 66 is slidably mounted on valve stem 64 and the upper and lower ends thereof are provided with apertures through which tie rods 62 and 63 respectively, extend. Crosshead 66 forms an abutment for one end of a coil spring 61 encircling valve stem 64, the other end of which abuts against a collar 68, which in turn abuts against the projecting end of piston 60, as shown in Fig. 4. Valve housing 58 is provided with a pair of chambers 69 and which are separated by a partition 1| having an opening therein through which the reduced portion 12 of valve stem 64 extends. The right hand side of partition (Fig. 4) is formed with a seat for the inner end of valve 65. Fluid motor 51 is connected to the pressure developed by pump 2 through the medium of a pipe connection 73 leading from a shuttle valve 14. Shuttle valve 14 is provided with a pair of fittings l5 and T6 to which are secured a pair of pipe connections l1 and 18 respectively. The inner ends of fittings and 16 are provided with seats for the plunger 14' of valve 14. The other ends of pipes 11 and T8 are connected to fittings l9 and 80' which communicate respectively with pipes 8 and 9 leading from pump 2. It therefore is seen that when pump 2 is delivering fluid pressure through pipe 8 the plunger 14 of shuttle valve 14 will be movedto the right (Fig. 6), thereby permitting fluid to flow through pipe 11, pipe 13, and

into the cylinder 59 of fluid motor 51. It is also seen that when pump '2 is adjusted so as to deliver fluid pressure through pipe 9, the plunger 14 of shuttle valve 14 willbe actuated to the left (Fig. 6), thereby permitting fluid to flow through pipe 18, pipe 13 and into cylinder 59 of motor 51.

Referring more particularly to Figs. 1, 3 and 4, pipes 50 and 5| are respectively connected to chambers 69 and 10 of valve housing 58 by a pair of pipes 19 and B0. Owing to the fact that the end portion 8| of valve 65, and the annular shoulder formed by the reduced portion 12 of valve stem 64 are equal in area, the pressure communicatedto chamber 69 through pipe 19 has no effect upon the valve 65. As stated hereinbefore, fluid motor 51 is connected to the pressure delivered by pump 2 at all times, and consequently when this pressure exceeds the tension of spring 6'! piston 60, and consequently valve 65, will be moved to the right, thereby unseating the latter and permitting the fluid to bypass through chambers 69 and 10, and inasmuch as chambers 69 and 10 are connected, respectively, to cylinders 40, 42 and 4| through pipes 19, 80 and 5|), 5|, the pressures in said cylinders will now be equalized. When this occurs pump 2 will adjust itself to neutral position and no further pumping action occurs. In pumps of this type it is well known that a certain force is required to maintain the same on stroke and that due to the centrifugal force of its rotating cylinder body it will assume a neutral position when this force is removed. Thus when pump 2 assumes a neutral position lever |8 will also assume a normal position intermediate stops 22 or 23 by virtue of the centering spring 30.

(Fig- 1). By this actionoflever1l8:link 29 will fulcrum about its-pivotal connection with: link 31 thereby causing link 35." and the, stroke adjusting mechanism 36 of'pump. I6 to move-tothe-right. When t thisy'occurs pump l6 -will,deliver"fluid pressure through: pipe 50" causing iafluid to enter cylinders 42 and 400i motor :14. thereby causing pistons-45 and 43 operating therein'to move to the left (Fig. By this action crossheadsi38 and =46 will also move to the left (Figs. 3 and 5) and to the right (Fig. -I), causing lever '52, and consequently the stroke adjusting mechanismjfi of pump 2, to move to the left. nPump 2. is now so .adjusted as to apply pressure to pipe 8 and suction to pipe 9, thus piston 6v of the hydraulic press 4 will move downwardly against .the material to be .formed in the mold 1. Upon movement of crossheads 38 and 46, .inthis manner, link 31 Will'also move to the right=(Fig. 1) and through its connection with link 29 which now fulcrums about its pivotal connection with rod 26 causes the link v35 and stroke adjusting mechanism '86 of pump l6 to move to the left, thereby adjusting the pump l6 toneutral position. Pistons-43 and 45, and-consequently the stroke adjusting mechanism 580i pump 2 will beheld in adjusted position due to the pressure in cylinders 40 and 42. Accordingly, fluid underpressure will continue to be delivered through pipe 8 and into the upper end of cylinder 5 of press 4, causing the piston 6 therein to continue its downward travel. When the piston 6' engages the material to be formed in the mold 1 considerable resistance is encountered and consequently the pressure developed by-pump 2 will gradually increase. The

spring 6'! associated with fluid motor 51 is adjusted to correspond with the maximum'pressure-required to compress the material in the mold 1. Consequently, when the pressure exceeds this predetermined value piston 60 of motor 5! will-moveto the right (Fig. 4) thereby unseating valve 65. When this occurs fluid from cylinders48 and 42 will bypassto-cylinder 41 throughpipe-SO, pipe'l9ychambers 69 and 10, pipe 88, and' pipe 51, thereby equaliaing the pressures acting on pistons 40,42 and 4!. Thus the pressure in cylinders 40 and'42 which holds the crossheads 38 and 45 and the stroke adjusting mechanism'56 of pump 2 in position is reduced and the pump is tion. This movement is communicated to rod'26- through links 31 and 29, causing lever! to move to normal position. Lever I8 will assume a position midway between stops 22 and'23 by virtue of the centering spring 32. This-movement of lever l8 to normal position indicates to the operator of the machine thatthe pressing operation on the material formed in mold 1 is completed. He thenagain grasps lever l8 and swings it to-the left. When this occurs the stroke adjusting mechanism 36 of pump l6 will be moved to the left causing the pump IE to be placed on stroke in the opposite direction. Pump l6 will now deliver fluid pressure to pipe 5| causing piston 44 or" motor I4, and consequently crossheads 38 and 45 to move to the right (Figs. 3 and 5). When this occurs lever 52, and consequently the stroke adjusting mechanism 56 of pump 2 will be moved heads 318 :and -48to theIright'pump-JIS :willbe actuated to neutral position through 1ink.31.a.nd linkZS, the. latter of which nowiulcrums-labout its pivotal connection withrod 26 thereby causing the stroke adjusting; mechanism 36 of pump i ito move to theright: (Fig. 1): to-normalin effective position. 'Pump 2 will be retained on stroke owing to the pressure in cylinder4l until piston 6 of the hydraulic press 4 engages the boss l2 at the upper. end thereof. .When this occurs thepressure developed by pump 2wil1 ropidly increase until it exceeds the tension of spring. 6'|.- Inasmuch as pump 2 is delivering pressure through pipe 9,'this pressure is communicated to the cylinder 59 of motor 51 through pipe 18, shuttle valve 14, and pipe 13, and when the pressure exceeds the tension of spring 61 valve 65 will be moved to the right causing fluid to bypass from cylinder 4| to cylinders! and 42 through-pipe, pipe '80,'chambers 10, and 69, pipe l9, and pipe 58, thus releasing the-pressure in cylinder 4| and permitting the pump to return to neutral position. Pistons 44 and-43, 45," and crossheads 38 and 46 of motor l4 will also return to neutral, and through the movement of link connections 3'! and 29,-rod 26 will cause lever 48 to move to neutral position where it will againbe centered by spring .32.

. By this construction it is seenthat pump 2 may-.be'placed on stroke'in either direction any amount between no stroke and full stroke posi tion, depending upon the extent of movement of lever "l8. After the lever! 8 is adjusted in'the manner just described, a power-mechanismflfunctions toplace the pump 2 on stroke where it is retained 'by'thepower mechanism-until the pres-' sure delivered thereby exceeds a predetermined value, when the pump is permittedto assume its normal inefiective position. "I'hus the-operation of the deviceis out of the control ofthe operator once the lever H! has been adjusted. This construction is highly desirable,- especially in connection with devices for forming materials in molds where the materials are formed bysubjecting them to predetermined pressures. --While the embodiment herein described is admirably adapted to fulfill the-objects primarily stated; it is to be understood that it isnot in-- tended to limit the invention to the embodiment herein shown since itmay be embodied in other forms, all coming within the scope of the claims which follow. 7

What is claimed is: 1; Ina device of the class describedthe combination with variablestroke' reversible -dis charge pump, of power means for adjusting the stroke'of said pump and retaining it-in adjusted dering the latter inefiective when the-pressuredelivered by said pump exceeds a predetermined value.

I 2. In a device of the class described, the -combination with a variable stroke reversible discharge pump, of means for adjusting the stroke of said pump, said means comprising a. fluid said pilot pump ineffective when the motor is operated in either direction, and automatic bypass means associated with said motor for rendering the latter ineffective when the pressure delivered by the pump first named exceeds a predetermined value.

3. In a device of the class described, the com bination with a variable stroke reversible discharge pump, of means for controlling the stroke and direction of discharge ofsaid pump, said means including a fluid motor having a plurality of pistons operating therein, a variable stroke reversible discharge pilot pump for actuating said fluid motor, manual means for conditioning said pilot pump for operation, and followup means for rendering said pilot pump ineffective when said motor has been operated a predetermined amount, and automatic bypass means for rendering said motor ineffective when the pressure'in said pump first named exceeds a predetermined value.

4. In a device of the class described, the combination with a variable stroke reversible discharge pump, of control means for placing said a pump on stroke in either direction, said control means comprising a fluid motor, a pilot pump for actuating said motor, and manual means for conditioning said pilot pump for operation, bypass means for rendering said motor inoperative when the pressure in said pump first named exceeds a predetermined value, said bypass means comprising a valve, a fluid motor for operating said valve, means connecting said last mentioned fluid motor to the pressure delivered by said pump, said connecting means including a shuttle valve whereby the pressure delivered by said pump in either direction is effective to actuate said bypass valve.

5. In a device of the class described, the combination with a variable stroke reversible discharge pump, of a control means iorregulating the stroke and direction of discharge of said pump, said control means comprising a fluid motor having a plurality of pistons operating therein, a pair of interconnected crossheads operatively associated with said motor, some of said pistons being adapted to engage one of said crossheads, and another of said pistons being adapted to engage the other of said crossheads, a pilot pump for actuating the pistons of said motor, manual means for controlling the operation of said pilot pump and followup means operatively connecting one of said crossheads to said pilot pump, whereby when the pistons of said motor have been operated a predetermined distance determined by said manual means said followup mechanism will operate to render said pilot pump inefiective.

6. In a device of the class described, the combination with a variable stroke reversible discharge pump, of control means for regulating the stroke and direction of discharge of said p ump, said control means comprising a fluid motor having a plurality of pistons operating therein, a pair of crossheads operatively associated with said motor, some of said pistons being adapted to en gage one of said crossheads, and another of said pistons being adapted to engage the other of said crossheads, a pilot pump for. operating said fluid motor, means for conditioning said pilot pump for operation, means for connecting one of said crossheads with the stroke and discharge regulating device of said first mentioned pump, and followup mechanism connecting the other of said crossheads with the stroke adjusting mechanism of said pilot pump whereby, when the pilot pump actuates the pistons of said motor a predetermined amount to place the first mentioned pump on stroke said followup mechanism will render ineffective said pilot pump.

7. In a device of the class described, the combination with a variable stroke reversible discharge pump, of stroke and direction of discharge regulating mechanism for said pump, fluid power means for actuating said mechanism in either direction, said fluid means comprising a motor having a plurality of pistonsoperating therein, a pair of crossheads operatively associated with said motor, a pilot pump for actuating the pistons of said motor, some of the pistons of said motor being adapted to engage one of said crossheads, and another of said pistons being adapted to engage the other of said crossheads, manual means for conditioning said pilot pump for operation, means connecting the stroke and direction of discharge mechanism of said first mentioned pump with one of said crossheads, followup mechanism for connecting the other of said crossheads with the stroke adjusting mechanism of said pilot pump, whereby when said fiuid motor has operated the stroke adjusting mechanism of said first mentioned pump a predetermined distance said pilot pump will be rendered inoperative, and automatic means associated with said motor for releasing the pressure therein when the pressure delivered by said first mentioned pump exceeds a predetermined value.

8. In a device of the class described, the combination with a variable stroke reversible discharge pump, of power means for adjusting the stroke of saidpump and retaining it in adjusted position, means for conditioning said power means for operation, automatic by-pass means associated with said power means for rendering the latter ineffective when the pressure delivered by said pump exceeds a predetermined value, and adjustable means controlling the operation of said bypass means.

9. In a device of the class described, the com bination with a variable stroke, reversible dis charge pump, of means for adjusting the stroke of said pump, said means comprising a fluid motor, a pilot pump for operating said motor, and manual means for adjusting the stroke of said pilot pump, followup means associated with said pilot pump and said motor for rendering said pilot pump ineffective when the motor is operated a predetermined distance in either direction, automatic bypass means associated with said motor for rendering the latter ineffective when 'the pressure delivered by the pump first named exceeds a predetermined value, and adjustable means associated with said bypass means for conditioning the same for operation at difierent predetermined pressures.

HARRY W. LINK.

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