US2317563A - Hydraulic brake - Google Patents

Description

April 27, 1943. w. R, TUCKER 2,317,563

HYDRAULIC BRAKE Filed May 25", 1940v s Sheets-Sheet 1 lzvvewm WAPPE/V P. 72/02? M I ii/Mid Armenia-Ya Ap 27, 1943. w. R. TUCKER HYDRAULIC BRAKE Filed May 25, 1940 3 Sheets-Sheet 2 e Mm W m Mr m F T m W m m m 5 n N-\/ U m? 9v L April 27, 1943. w. 'R. TUCKER 2,317,563

HYDRAULIC BRAKE Filed May 25, 1940 3 Sheets-Sheet 3 Wyn r02? meg 3v e wax 2 H 67 7 LL. A TTGFNEYJ Patented Apr. 27, 1943 UNITED STATES PATENT OFFICE Hydraulic Development Corp. Inc., Wilmingt Del., a corporation oi Delaware Application May 23, 1940, Serial No. 336,792

4 Claims. (01. 100-41) This invention relates to presses, and in particular to presses having a plurality of spaced pressing plungers connected with one and the same platen. Such machines, which are particularly useful for forming long extended parts, such as airplane wings, and which include the so-called press brakes, shear brakes and bending brakes, have heretofore been operated mesive in manufacture.

Accordingly, it is an object of the present invention to provide a machine which will overcome the above identified drawbacks.

It is a further object of the invention to provide a multi-plunger press of the above identifled character, in which synchronous movement of the spaced plungers connected with the ends of the pressing ,platen, bending beam or shear is assured by hydraulic means.

Another object of the invention is to provide a machine, as set forth in the preceding paragraph, in which the fluid expelled by the pressing plungers during the working stroke thereof, is controlled so that the quantity of fluid escaping from each working cylinder is the same.

A still further object is to provide a press for forming a long extended workpiece, which comprises a plurality of spaced cylinder piston assemblies having throttling means associated therewith for throttling the exhaust of said cylinder piston assemblies, so as to insure synchronous movement of the parts of said cylinder piston assemblies.

A still further object of the invention consists in the provision of a press of the above identiiied type in which the pressing members are automatically slowed down at the end of the movement thereof, and with further hydraulic means .for slowing down the movement of said plungers at the end of their retraction stroke.

These and other objects and advantages of the invention will appear more clearly from the following speciflcation in connection with the accompanying drawings, in which: 1 1

Figure 1 illustrates the assembly of a press according to the present invention.

Figure'2 shows, on a somewhat larger scale, the left portion of the machine illustrated in Figure 1.

Figures 3 and 4 are further embodiments of a cushioning device used in connection with the present invention.

Figure 5 diagrammatically illustrates a hydraulic circuit for a press according to the invention. 1

General arrangement In general, the press, according to the invention, comprises a plurality of spaced hydraulically operable plungers connected with a press platen, beam or shear, said plungers beingassociated with throttling means adapted automatically to provide for an equal discharge to exhaust by all pressing plungers. More specifically, when one pressing plunger connected with one end of the pressing platen, bending beam or shear, tends to run ahead of another pressing plunger connected with the opposite end of the pressing platen, bending beam or shear, the said throttling means control the fluid expelled by the respective pressing plunger so as to brake the latter, thereby maintaining synchronous movement of all plungers.

Structural arrangement Referring to the drawings in detail, I designates the press bed connected with the press head 2 by means of strain rods 3 and nuts 4. Conncted with the press head by screws 5,01 by any other convenient means, is a cylinder head 8. Similarly, a cylinder head 1 is connected by screws 8 with the press bed I. Reciprocably mounted in the cylinder heads 6 and I arepis- I pistons and the ram II and beyond the pistons.

The ends of the rod l3 extend slidably through extremely close fitting guides l4 and I5 formed in the ends of the cylinders 6 and I respectively,

and also extend into the cavities I8 and I1 I pressure fluid into the pressure cavities I8 and formed in the cylinders 3 and I respectively, in a manner which 'will presently appear. 7

The plates I2 are formed with an annular abutting ortion 28, which is adapted to abut the inner faces 22 and 23 of the ends of the cylinders 6 and 7 respectively. The plates I2 are each further provided with an annularrecess within which is received a floating ring 26. The floating ring 24 is held in place by the plate I2, and is allowed to move radially to prevent bending of the valve rod I3 due to any misalignment thereof with thering 24 and the guides I4 and IS. The rings 24 slidably engage the surfaces of the rod I3 with an extremely close clearance, whereby the escape or pressure fluid from the ring along the valve rod I 3 is prevented. This construction is extremely reliable and compact and allows the valve rodto shift readily without having the seal destroyed. It will be understood that the rings 23 likewise engage the surfaces of the plates I2,

and of the pistons 3 and II slidably, but with extremely close clearance.

The valve rod' I3 has axial holes 25 and 23 respectively, drilled from its ends, and the ends oi. the valve rod II are machined with slots 21 and 23 respectively connecting with the holes 2! and 28. On the upper end of the rod I3, toward the inward end oi. the hole 23, are four radial connecting holes, these connecting holes 23 being relatively large in diameter and adapted to freely connect the hole 25 with the chamber I3 in the cylinder 8. The lower end of the rod I3 is simi- -larly provided with identical holes 30.

7 located outwardly from these holes 28 and are a series of longitudinally spaced connecting holes 3| and 32 respectively, being progressively more closely spaced, and progressively smaller in diameter as one proceeds outwardly from the holes 23 and 30. These holes 3| and 32 are preterably disposed in a single row on only one side of the rod I 3 instead of extending into four directions as do the holes 29 and 30; and these holes 3| and 32 likewise communicate with the holes 25 and 2B.

The ends of the rod I3 are adapted to abut against threaded plugs 33 and 34, which are threadedly mounted in the ends of the cylinders 3 and 1 respectively. These plugs 33 and 3| are covered by removable end caps 35 and 3B respectively, which serve to prevent unauthorized.

changes in the posltlon oi the threaded plugs, and also serve to prevent oil leakage around the threads oi the plugs.

Communicating with the chambers I8 and II are passageways 31 and 38 respectively, which are adapted to act as either inlet or discharge conduits depending upon in which direction the ram or plunger I l is being moved.

The plugs 33 and 34 are so adjusted that when the rod I3 abuts against one of them, theslot 21 or 23 in the other end of the rod I3 is adapted to freely interconnect the passageways 31 or 33, and the chamber It or II with the pressure cavities is or :0, this being accomplished by hava ing slots 21 and 23 of such a length that the slots extend into the interior of the chamber I9 or 20.

This is indicated at the upper end oi Figure 2,

wherein the slot 21 has a considerable portion 5 disposed within the chamber I3, and hence is adapted to allow free entry oi! the pressure fluid from the passageway 31 into the chamber I3, where it may act upon the piston 3 to move the same away from the fluid inlet.

When the rod I3 abuts either of the plugs 33 or 34, its slot 21 or 28 'is in non-communication relationship with the pressure cavities I9 or 20, as is indicated in the lower portion of Figure 2, whereby, when the pressure fluid is first admitted; its first action is to move the rod I 3 axially into engagement with the other plug 33 or 34. This action also serves to press the slot 21 or 28 in communication with the chamber I9 or 20, thereby allowing the pressure fluid to act upon the 20 piston 9 or III.

As will be seen from Figure 2, the ram or plunger II is provided with collars 39 and 40 engaging correspondingly shaped recesses in a member 4] threaded into the platen or beam 42.

5 The beam or platen 42 is provided with bushings l3 slidably engaging the strain rods 3 for guiding the platen or beam 42. In this way, movement of the pistons 3 and It will cause a corresponding movement oi the platen or beam 42.

Packing material 44 and 45, compressed by glands l6 and I1, prevents'leakage iron th cylinders 6 and I.

While according to the embodiments of Figure 2, the ram or plunger II is brought to a stand- 35 still by engagement of its plates I2 with the adjacent surfaces 22 and 23 respectively, in other words in a mechanical manner, according to Figures 3 and 4, hydraulic stop means are provided.

The parts of Figures 3 and 4, which are similar 40 to those described iniconnection with Figure 2, are designated with the'same reference numerals, however, with the additional character a and b,

respectively.

The cylinder Ia of Figure 3 comprises a cylinder chamber 43 in which the piston la is reciprocably mounted. A conduit 43 communicates with the upper portion of the cylinder chamber 48, whereas the lower portion oi the cylinder chamber 48 communicates through a conduit III with a tonnage control valve 5|. The tonnage control valve II comprises pressure responsive means, which at the attainment oi a predetermined pressure in the chamber 48, below the piston Illa, causes a change in an electric circuit comprising means for reversing the direction 01' delivery of the pressure pump, thereby initiating the retraction stroke of the ram or plunger Ila.

The tonnage control valve BI does not form a part 01 the invention, and for a more detailed description thereof, reference may be had to patent application, Serial No. 214,772 to Walter Ernst, flled J1me 20, 1938.

A cylinder Ia, comprising a boss 52 with cavities 53 which communicate with a conduit 38a extending into the cavities 33, has a valve-rod I3a, which is adapted to engage an adjusting screw 34a. The longitudinal bore in the lower end of the valve rod I3a communicates with a lateral bore 83a adapted to allow passageof fluid from pipe 33:: into cylinder Ia-when the valve rod l3a is in its upper position. Leakage along the ad- 'iusting screw 34a is prevented by packing material 5| compressed by a gland SI and a tighteningnut l6. j

The holes 32a in the rod Ila are so arranged a conduit 04.

that they are completely covered up before the piston Ia can engage the lower surface of the cylinder chamber 40. In this way, there will always be a fluid cushion .between the lower portion, of the cylinder. chamber 40 and the adjacent surface of the piston I0a. The embodiment of Figure 4 is very'similar tothat of Figure 3, but differs in that the tonnage control valve 5|, together with, the conduit 0, is replaced by the mechanism shown on the right hand of cylinder 11), illustrated in Figure 4. Ac-

cording to this mechanism,-the adjusting screw 34a is replaced by a plunger 51 connected by means of a bracket 58 with a limit switch 09. The limit switch 59 has a lever 60, supporting a roller SI adapted to be engaged by any convenient means, for instance, the actuating member 02 adapted to be operated by the beam or platen 42 in cooperation with the movement of the pressing plungers II. The plunger 51 may be adjusted relative to the cylinder 1b, and the limit switch 59 may be adjusted relative to the actuating member 62, by lifting or lowering the bracket 58. To this end, the bracket 58 has connected therewith a nut 63 engaged by an adjusting screw 04 having a handle 65 and being rotatable, but not axially slidable in a fixed bearing ,06. Rotation of the screw 04 in one or the other direction willlift or lower the bracket 58, thereby determinin the point where the end of the valve rod I3b will engage the adjacent front face of the plunger 01. Referring now to Figure 5, it will be noticed that the passageway 31 of the cylinder 0 is con-- nected by means of a conduit 51 with thepassageway 31 of the cylinder 60. Similarly, the passageway 38 of the cylinder 1 is connected by means of a conduit 88 with the passageway 30a of the cylinder 10. The lower portion of the cylinder chamber I9, below the piston 9, is connected by means of a conduit 09 with the lower portion of the cylinder chamber I90, below the piston 90.

The upper portion of the cylinder chamber 20. above the piston I0, communicates through a conduit 10 with the upper portion of the cylinder chamber 200, above the piston I0c.

Branching off the conduit 51 is a conduit 1I leading to a shuttle valve 12 with a cylinder chamber 13 and a shiftable member 15, a branch conduit 15 connecting the lower portion of the valve chambers 13 with the conduit 68. upper and lower portion of the valve chamber 13 may communicate with a fluid tank 16 through conduits 11 and 18. -A conduit 10 leads from the fluid tank 16 to the suction side of a pump 80, the .pressure side of which communicates through a conduit 8| with the middle portion of the valve cylinder chamber 13. s

As will be seen from Figure 5, the position of the valve member 14 will determine whether Pressure fluid from the pump 00 is passed into the The asmsca into the conduit 00. I The interior of the choke valve 00 communicates through a conduit 00 with an automatic feed control valve, generally designated 0|. This feed control valve, which in itself, does not form a part of the invention, and

which is more fully explained in Patent 2,146,537 to Farnham, comprises a cylinder 82 with spaced cylinder chambers 83, 04, and 88. Mounted in the cylinder chamber 08 of the valve II is a spring 01, engaging with its lower end the bottom of the chamber 90, while the upper end of the spring 01 engages the lower portion of a plunger 08 passing through the chambers 95 and 94, and normally extending into the chamber 93.

The plunger has a longitudinal transverse bore 08 with a tapered upper portion I00. The longitudinal bore 90 is adapted to effect communication between the chambers 94 and 98. The chamcates with the conduit 58 between the said check valves. The valve SI furthermore comprises, at

the lower portion of the chamber 96, a breather opening I".

symmetrically to the choke valve 85 and the feed control valve 0|, are provided a choke con-- trol valve I00 and a feed control valve I01. The construction of the choke control valve I08 and feed control valve- I01, fully corresponds to that conduit II or the conduit 15. A third line 02 I leads from the fluid tank 10 through'a pressure relief valve 83 to the conduit II. The conduit 0| also communicates with ,the conduit." through of the choke control valve 05 and the feed control 'valve II, so that a further description of the valves I00 and I01 is superfluous. Similarly to the choke valve 83, the choke valve I06 communicates through a conduit 8811 with the conduit. 15 and through a conduit !0a with the passage Illa and I020 of the feed control valve I01, which latter communicates through a conduit I03a with the conduit 80.

Operation stroke, and that it is now desired to perform a retraction stroke, the valve member 14 is shifted so that the conduit 15 communicates with the conduit 0i, while communication between the conduit Hand 11 is established. Pressure fluid will then be delivered by the pump through the conduit ll and the conduit 15, and will flow through the check valve I04 and the conduit 08. Into the passageway 38 where it will act upon the slot 20 of .the valve rod I3.

' The pressure acting upon the slot 20 will lift the valve rod I! to'such an extent that it abuts the nut 30. After this movement has been effected, the slot 20 will communicate with the lower part of the chamber 20, so that the fluid Dres'suredelivered by the pump 00 through the conduit '00 'will act upon the lower area of the piston II. Since the'lower area of thepiston II is larger than the upper area of the piston 10, the latter will be moved upwardly, although the upper area of thepiston I0 communicates through the conduit 1| and the conduits 84 and 0| with the pressure side of the pump ll.

pump 80, thereby aiding the retraction stroke.

o! the piston I0. This results in a speeded up retraction stroke of the ram II.

It is, of course, understood that a part oi the fluid delivered by the pump 80 will pass through the check valve I05, and the conduit "a into the passageway 38a, where it will actuate the piston We in the same manner as described in connection with the piston I0.

During the upward movement of the ram II, the piston 9 connected with the ram II, will likewise be moved upwardly. During this operation, the space below the piston 9 will be fllled by fluid from the fluid tank 16, due to the suction effect caused in the conduit I and 69. The fluid expelled by the piston 9 enters the passageways 29 and ports 3| and passes through the bore 25 and the slot 21 into the passageway 31. From here it flows through the conduit 8! and II through the valve I2 and the conduits I1 and 13 into the fluid tank I6.

Similarly, fluid passes through the conduits I08 and 69 into the space below the piston 30 while fluid expelled by the piston 9c passes through the holes 290,- bores lie and slot 21c into the passageway 310. From here it escapes through the conduit 51, 1|, valve I2 and conduit TI and I8 into the fluid 'tank I0. Since during this retraction stroke of the rams I I, He no load acts upon the said rams, the latter will move substantially synchronically.

When the pistons 9 and 9c approach the last portion of their upward stroke, they gradually cover up the ports 3|, thereby restricting the escape of fluid from the upper portion of the cylinder chambers I9, I90, and gradually slowing down the movement of the rams II, Me. When the last port 3i is covered up, no fluid can escape any more from the cylinder chambers I9, I30, and the rams II, He come to a halt. In this position, the pistons 9, 9c engage the upper abutment surfaces 22, 22c 01 the cylinders 6, 30. Ex-

cess fluid now delivered by the pump 30 will be discharged through the fluid pressure relief valve 83 into the fluid tank I8.

If it is now desired to perform a working stroke, the valve member '14 is shifted into the position shown in Figure 5. As will be clear from the said figure, pressure fluid is now delivered by the pump 80 through the conduits 8|, "II and 31 into the passage 31, and 31c where it acts upon the slots 21 and 21c 01 the valve rods I3, I30. The valve rods I3, 13c are moved downwardly by the pressure acting upon the said slots 21, 21c until the valve rods I 3, I30 engage the plugs 34, 34 As soon as this position is reached, the pressure fluid in the passageways 31 and 310 poses through the slots 21, 21c intothe upper portion of the chambers I9, I90 where it acts upon the pistons 9 and 9c to move the same downwardly. The fluid pressure below the pistons 0, 9c escapes through the conduits 69, I00 into .the fluid tank I6.

The pistons I0 and I 00 connected with the pistons 9, 90 by means of the rams II, I lc likewise move downwardly, and the space above the pistons I0 and Me is filled by pressurefluid delivered-by the pump 80 and flowing through the conduits 8 I, 84 and I0. In other words, the pressure fluid entering the upper portion of the chamhere 20 and 200 directly aids the pressure fluid acting upon the upper surface of the pistons 9, 9c. The fluid expelled by the pistons I0, I00 during the downward movement of the said pistons passes through the holes 30, 30c and the ports 32, 32c into the bores 26, 260. From here it escapes through the slots 28, 280 into the passageways 30, 380. From there the fluid passes through the conduits 00, I03 and 00a, I034 into the chambers 05 and 35a of the feed control valves 0|, I 01 respectively. The valves I04 and Ill bar communication between the conduits 30, and 33a, and the conduit IS. The fluid in the chamber 05 of the valve 3i now passes through the slot 33 into the chamber 04 and from there through the conduit 90 into the choke valve 35. From here the fluid passes through the choke valve port 31 into the conduits 33 and .15 through the valve I2 and the conduit I0 into the fluid tank I3.

According to the adjustment or the screw 30, a greater or smaller quantity of fluid will be allowed to pass through the port 01. Similarly, the fluid in the chamber 050 passes through the slot 9011, the chamber a, the conduits 33, the choke valve I03 and the conduits 304:, II, the valve "and conduit II into the fluid tank Il.

Supposing now, that the workpiece is so located, with respect to the platen or beam connected with the rams II, He that the workpiece re-acts only against the ram II c, or with a substantially greater force against the ram Iic than ainst the ram II. In this instance, the ram I I tends to run ahead of the ram I lc which, it it were possible, would result in a cocking oi the platen. However, according to the present invention, this is prevented in the following manner. As soon as the ram II and thereby the piston I0 tends to run ahead ofv the ram lie, the pressure in the conduit 30 and. I03 tends to increase. This pressure is conveyed through the passage I02 upon the plunger 00 and moves the latter against the thrust of the spring 01 downwardly, to a certain extent. This causes a reduction of the orifice, effecting communication between the slot 90 and the chamber 0|, and thereby restricts the quantity of fluid which may pass from the conduit I03 into the conduit ll,

so that only the same quantity of fluid as hetore may pass through the valve opening 81. In other words, the fluid escaping from the choke valves 85 and I 08 is equalized, so that synchronous; i movement of the rams Ii and lie is assure As soon as the pistons I0 and Ne approach the end of their downward stroke, they will gradually cover up the holes 30, 30c and bores 32. 32c. thereby gradually slowing down the movement of the rams II, He, and finally bringing the said rams to a halt when all holes and ports 30, 30c,

32, 320 are covered up. In this position, the,

pistons I0 and I0c engage the lower abutting surfaces 23 and 230 of the lower'portlons oi the cylinders I, Ic. Any excess fluid delivered by the pump is then conveyed through the pressure relief valve 83 into the tank I6.

While, according to the structure of Figure 5, throttling means are provided only in the exhaust conduits 00, 08a, it is, of course, possible to provide similar throttling devices in the conduit 01. However, since'as previously mentioned no substantial load acts upon the rams II, He during the upward movement, there is no danger of a cocking of the platen so that generally, no throttling devices are required in the conduits 01.

Although the operation with regard'to Figure 5 has been described so that the pistons 3, 0c and III, I 00 engage at the end of their strokes, either the abutments 22, 22c of the cylinders 0, 80, or the abutments 23, 230 of the cylinders I. la, it is self-understood that by adjusting the plugs 33, 33c and 34, 340, the movements of the embodiment of Figure 3 may be employed. Ac-- cording to this embodiment, the attainment of a predetermined pressure in the lower space of the chamber 48, below the piston Illa, will actuate the tonnage control valve 5|, thereby automatically shifting the valve 14 and causing the reverse movement of the platen.

It is also understood that the shifting movement of the valve member 14 may be eiiected automatically in any other desired manner, for instance, by actuation of the platen, when the latter has reached a predetermined point.

With respect to the last mentioned embodiment where the platen, or a member connected with-the platen actuates means such as a limit switch for reversing the movement of the platen, it may be desired to enable a simultaneous adjustment of the valve rod, i. e. the degree of the slow-down movement of the respective pistons and the time when the limit switch is actuated. Such an adjustment is made possible by the device shown in Figure 4. To this end, the handwheel 65 and the screw 64 connected therewith has merely to be rotated, whereby the bracket, 58 carrying the abutments 51, and the valve rod Rb, and the limit switch 59 to be operated by the member 62, will be lifted or lowered in accordance with the direction in which the handwheel 65 is rotated. A lifting of the abutment 51 will cause an earlier stop of the'piston Illb, while the lifting of the limit switch 59 will enable an earlier actuation thereoi by the member 62 connected with the platen. A lowering of the bracket 58 will, of course, have the opposite effect.

It will be understood that I desire to comprehend within my invention such modifications as ling means comprising metering ports and passageways associated with said motor means and adapted to cooperate with said motor means to stop the latter,- switch means operable by said platen or beam at a predetermined point, and adjusting means adapted simultaneously to adjust the controlling means and said switch means for determining the end of the working stroke or said platen or beam and the initiation of its retraction stroke.

2. In combination in a press, spaced hydraulic .HIOtOIS, a platen or beam interconnecting said motors and adapted to be reciprocated thereby, a fluid source for supplying pressure fluid to said motors to actuate the same, hydraulic means adapted to maintain synchronous movement of said motors, a plurality of valve rods hav metering ports and passageways therein, hydraulic means associated with said valve rods for hydraulically stopping said motors, switch means operabl by said platen or beam for reversing the direction of said motors, and means adapted simultaneously to adjust said valve rods and switch means for varying the point at which the platen or beam is stopped and its movement reversed.

3. In combination in a press, hydraulic motor means, a press platen reciprocable by said motor means, means operable in response to a predetermined travel of said motor means for slowing down said platen near the end of its workinfl stroke, control means for varying said slow down operation, reversing means for initiating the reversal oi. said platen, and adjusting means common to both said control means and said reversing means for adjusting the same.

4. In combination in a press, hydraulic motor means, a platen or beam reciprocable by said motor means, reciprocable means operable to reduce the speed of said platen in response to the travel of the latter over a predetermined distance,

may come within the scope of the claims of the motor means and reclprocable thereby, controlcontrol means associated with said reciprocable 1 means for varying said predetermined distance, reversing means for reversing the travel or said platen, and an adjusting member operable to eilect both an adjustment or said control means and of said reversing means.

WARREN aurucxna.

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