US3030880A

US3030880A - Hydraulic press brake and hydraulic system therefor

Info

Publication number: US3030880A
Application number: US68471A
Authority: US
Inventors: Stanley E Keagle
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-11-10
Filing date: 1960-11-10
Publication date: 1962-04-24
Anticipated expiration: 1979-04-24

Description

April 24, 1962 s. E. KEAGLE 3,030,880 g HYDRAULIC PREss BRAKE AND HYDRAULIC SYSTEM THEREFOR I Filed Nov. 10, 1960 3 Sheets-Sheet 1 INVENTOR. STANLEY E. K54

FIG. 5

April 24, 1962 s. KEAGLE 3,030,880

HYDRAULIC PRESS BRAKE AND HYDRAULIC SYSTEM THEREFOR Filed Nov. 10, 1960 3 Sheets-Sheet 2 FIG. 5

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United States Patent 3,030,880 HYDRAULIC PRESS BRAKE AND HYDRAULIC SYEiTEM THEREFOR Stanley E. Keagle, 2626 Nassau St, Sarasota, Fla. Filed Nov. 10, 1960, Ser. No. 68,471 14 Claims. (Cl. 100-269) This invention has relation to hydraulic press brakes and more particularly to the type of press brake that travels a portion of the work stroke unloaded or under relatively light loads and then must exert a relatively greater force to accomplish a desired operation.

Present hydraulic presses use a single stage cylinder for power. In order to have enough force for heavy jobs at a safe working pressure the piston of the power cylinder must be relatively large. The filling of the cylinder then tages a considerable amount of time. This slows the production of the press and limits its output and usefu1- ness.

A hydraulic press made according to the present invention incorporates a hydraulic power cylinder of relatively small size that will rapidly advance a press platen to the Work and when the force on the work exceeds a predetermined value an auxiliary hydraulic system becomes operative to make the force upon the work a multiplication of the force exerted by the hydraulic power cylinder.

In the form of the invention as shown, this force multiplication is obtained through utilization of a two-section platen that is resiliently held together when the platen is under no load. As disclosed, the piston rod for the main power cylinder is slidably fitted through the upper platen section and engages a cylindrical opening that has been bored into the lower section. The piston rod end surface acts as a separate piston when it moves within the cylindrical opening in the second section. This cylindrical opening is connected in parallel with a plurality of auxiliary cylinders bored into the lower section of the platen. The upper section of the platen has an equal number of auxiliary pistons fixedly attached thereto and extending into the respective cylinders in the lower section. The cylinder in the second section for the power cylinder piston rod and the connecting passages to the auxiliary cylinders contain hydraulic fluid and form a closed hydraulic system. When a predetermined force or pressure has been reached in this closed system the upper section of the platen is locked with respect to the press frame. The power piston rod continues to move within the cylindrical opening in the lower section of the platen, a hydraulic pressure continues to be built up within said cylindrical opening and an equal pressure will result in each of the auxiliary cylinders. This causes the lower section of the platen to move with respect to the upper section against the action of the resilient means that urges the sections together. The total force exerted by the lower section will be proportional to the number of auxiliary cylinders and their respective cross sectional area in relation to the cross sectional area of the power piston rod acting in its cylindrical opening in the lower section. The force exerted by the lower section of the platen is applied directly to the work. When the power cylinder is retracted the upper section of the platen is released and the two sections are again resiliently urged together and will move as a unit.

Utilization of auxiliary cylinders and pistons in the two-section platen will allow any desired multiplication of force on the work. The movement of the lower section of the platen with respect to the upper section will be proportionally less than the movement of the power piston rod and this will be dependent on the number of the auxiliary cylinders in the lower section and their respective sizes.

It is an object of the present invention to present a device that will automatically provide a multiplication of force exerted by a hydraulic press after the work has been contacted.

In the drawings:

FIG. 1 is a front elevational view of a hydraulic press made according to the present invention with parts broken away to show a hydraulic pump and control valve;

FIG. 2 is a top plan View of the device of FIG. 1;

FIG. 3 is a view taken as on line 3-3 in FIG. 2 with parts in section and parts broken away;

FIG. 4 is a sectional view taken as on line 44 in FIG. 2; and

FIG. 5 is a sectional view taken as on line 55 in FIG. 4.

Referring to the drawings and the numerals of reference thereon, a hydraulic press 19 includes a frame 11 that has two outer

longitudinal members

12, 12 and two inner

longitudinal members

18, 18. Each outer member and its respective adjacent inner member are fixedly joined together adjacent first ends thereof with end members 13, 13. A cylinder support 14 fixedly joins the two inner members adjacent said first ends. An anvil 15 is fixedly positioned against integral upright portions 16 of the longitudinal members at a second end of said longi-' tudinal members.

A hydraulic power cylinder 17 is fixedly positioned against cylinder support 14 and extends toward anvil 15 between

inner members

18, 18. A piston rod 26 is attached to an internal power piston 28 and extends to engage a platen 21 that is slidable on the longitudinal frame members and extends therebetween. Platen 21 consists of a first section 22 and a second section 23 that are re-' siliently urged together by a plurality of springs 24 acting on bolts 25 that in turn are slidable in first section 22 and fixedly attached to said second section 23.

First section 22 of the platen has two fixedly attached

guide shafts

26, 26 that extend substantially parallel to the longitudinal frame members and are slidably mounted through

guide blocks

27, 27 each of which is supported by the longitudinal frame members and is fixedly retained thereto by

notches

29, 29.

Guide blocks

27, 27 are braced back to end members 13, 13 with

struts

30, 30.

A first brake block 31, and a second brake block 32 are pivotally attached to each of guide blocks 27 with a pin 38 and are positioned to engage each of the guide shafts 26. Each of the second brake blocks 32 has a cylinder 33 bored into it and a pressure tight piston 34 fitted within said cylinder. A rod 35 is fixedly attached to the brake piston and extends slidably through first brake block 31. A nut 36 is threadably fitted onto rod 35 and engages first brake block 31 and moves the blocks toward each other where the piston is acted upon by hydraulic pressure. An oil passage 37 is located in each of second brake blocks 32 and opens into cylinder 33 between piston 34 and the interior end of the cylinder.

Piston rod 20 is slidably fitted through first section 22 of the platen 21 and extends to slidably engage a master cylinder 40 in the second platen section 23. A lower surface 19 of rod 20 acts as a master piston within said master cylinder. A plurality of slave pistons 41 are fixedly attached to the first platen section 22 and each extends to slidably engage an aligning slave cylinder 42 located in second section 23. A pressure tight element 43 seals each of the slave cylinders 42 and master cylinder 40 with respect to their respective pistons. A port 44 connects all of the slave cylinders 42 and master cylinder 46 in parallel and provides passageway for hydraulic oil to flow between said cylinders. A pair of

pressure lines

45, 45 are connected to port 44- and one of said lines is connected to passageway 37 in each of the

second brake blocks

32, 32. With the two sections of the platen contiguous, the pistons 41 extend substantially to the bottom of their respective cylinders and the piston rod 20 is posi- 3 tioned with the end surface 19 thereof adjacent the outer end of master cylinder 40. Port 44, the pressure lines 45, 45 master cylinder 40, slave cylinders 42 and

brake cylinders

33, 33 in each of the brake blocks 32 are filled with hydraulic oil. This system becomes an independent closed circuit hydraulic system.

A cross arm 46 is fixedly attached to piston rod 20 and has two bolts 4-7, 47 slidably mounted therein. Bolts 47, 47 are fixedly attached to first section 22 of the platen. When the piston rod is retracted, cross arm 46 engages the head portions 50 of the bolts and thereby moves the platen to a retracted position.

The frame 11 and associated parts are supported by a cabinet 51 or other suitable structure. Hydraulic fluid under pressure is supplied to the power cylinder 17 by a hydraulic pump 52 that is driven by an electric motor 53. A control valve 54- is employed to divert flow from the pump selectively through a first oil line 55 or a second oil line 56, each of which are open to the interior cylinder 17 on opposite sides of the internal piston. A relief valve 57 is connected in one of the oil lines to prevent excessive pressure buildup in the line.

Any tendency of the second section of the platen to cock or bind with respect to the first section is counteracted by pinion gears 58, 58 drivably mounted on a transverse torsion shaft 59 that is rotatably mounted on brackets 60, 6t; which in turn are fixedly attached to the second section 23 of the platen with bolts 61, 61. A rack 62 is fixedly attached to each of the outer longitudinal members 12 and each rack extends inwardly therefrom to drivably engage one of pinion gears 58. Thus, if one of the ends of the second section of the platen tends to cock when loaded, the unequal movement of the ends is restrained by the rack and pinion acting through the torsion shaft 59 and brackets 60. The pinion gears will not twist with respect to each other but must rotate together. When the second section of the platen tends to cock one of the brackets 60 will tend to move more than the other. This in turn tends to rotate one of the pinion gears 58 more than the other. The rotational movement of the pinion gear is transmitted by shaft 59 to the other pinion gear, thereby equalizing the movement of both ends of the second section of the platen or alternatively equalizing the load exerted at the ends of the second section if additional movement is not possible. A slot 63 is provided in each of the inner longitudinal members 18 for the torsion shaft 59 so that it may move longitudinally.

Operation When the press is to be used, as for example to make permanent a fold in the signatures of a book 64, the motor 53 is started and the hydraulic pumpv 52 is thereby activated. The book 64 may be placed on the anvil 15 and the power cylinder 17 activated by moving the hydraulic control lever to position to divert flow through line 55 to the interior of said cylinder. The first and second sections of the platen will be contiguous to form a single unit under the action of springs 24 acting through bolts 25. The brake blocks 31 and 32 will be released from both guide

shafts

26, 26 and the guide shafts may move freely in guide blocks 27, 27. The power piston 28 and the piston rod 20 will be extended by the hydraulic pressure in cylinder 17 and will move the platen toward the anvil by the pressure on the end surface 19 of the piston rod 20 bearing on the column of hydraulic oil in master cylinder 40. The spring 24 holding the two platen sections together will be adjusted to counteract the pressure necessary to move the platen under no load, thereby insuring that the section will move as a unit. When the platen contacts the work piece, the pressure within master cylinder 40 will rise and the resulting pressure in cylinder 33 in each of the second brake blocks 32, 32 will cause the first and second brake blocks to move together and lock each of the guide shafts from further sliding movement. As the piston rod continues to slide within master cylinder 4t) the hydraulic oil within the cylinder will be forced through port 44 to the slave cylinders 42 and the pressure in the slave cylinders 42 will be equal to the pressure in master cylinder at This pressure acting on the slave pistons 41 will force the second section of the platen to move against the work and away from the first section of the platen. This action is best illustrated in FIG. 2. The total force exerted on the work is determined by the number of slave cylinders and the area of said slave cylinders in re lation to the area of end surface 19 of piston rod 20 and master cylinder 40. As illustrated, with four slave cylinders each with a cross sectional area equal to the cross sectional area of master cylinder the total force exerted on the work by the second section of the platen will be four times the force exerted by piston rod 20, minus the force necessary to overcome the force from springs 24. Conversely, the movement of the second section of the platen with respect to the first section thereof will be one-fourth of the movement of piston rod 20 within master cylinder 40.

When oil is diverted from the pump through line 56 to power cylinder 17 the power piston rod is retracted,

' the pressure in master cylinder 40 is thereby relieved and the brake blocks holding the

guide shafts

26, 26 will be released. The springs 24 will resiliently urge the two sections of the platen into contacting relationship. As piston rod 20 retracts, cross arm 46 will contact bolt heads and the bolts 47 will in turn move the platen away from the work as the piston rod continues to be retracted The power cylinder 17 may be of a size to permit rapid filling until the work is contacted, thereby making the unloaded stroke of the platen fast. When the work is contacted the lower section of the platen will automatically move in relation to the first section with a force multiplication thereby insuring sufficient power to accomplish most press brake jobs. The stroke will then also be proportionately slower to make control of the platen easier. The return stroke also will be rapid because of the relatively small size of cylinder 17.

While the device as disclosed is shown operating in a horizontal position a vertical press brake may utilize the same type of platen. Also a V-die or other metal forming equipment may be inserted into the press brake and equally excellent results will be obtained. The rapid return and unloaded strokes of the piston rod greatly increase the eificiency and total output of the press brake. The total force that may be exerted by the brake will still be large enough to accomplish most heavy jobs.

What is claimed is:

1. A hydraulic press brake including a main frame, a work anvil mounted with respect to said frame, a hydraulic power cylinder mounted with respect to said frame, a power piston slidably mounted in said power cylinder, a source of fluid under pressure, a conduit open to said source of fluid under pressure and to the interior of said power cylinder, control means in said conduit for selectively diverting said fluid under pressure to said power cylinder, a first platen section slidably mounted with respect to said frame, a second platen section slidably mounted with respect to said first platen section, bias means urging said platen sections together, a piston rod link operably associated with said power piston, a master hydraulic unit comprising 'two master hydraulic components, namely a master cylinder and a master piston operably associated with said master cylinder, with one of said master hydraulic components being operably associated with said second platen section and the other of said master hydraulic components being operably associated with said piston rod link, at least one slave hydraulic unit comprising two slave hydraulic components, namely a slave cylinder and a slave piston operably associated with said slave cylinder, with one of said slave hydraulic components operably associated with said first platen section and the other slave hydraulic component operably associated with said second platen section, there being a passageway open to the interior of said master hydraulic unit and the interior of said slave hydraulic unit, the interior of said master hydraulic unit, the interior of said slave hydraulic unit and said passageway constituting a closed hydraulic system, and means for immobilizing with respect to said frame the platen section located farthest away from said anvil responsive to increase of pressure in said closed hydraulic system.

2. A hydraulic press brake including a main frame, a work anvil mounted with respect to said frame, a hydraulic power cylinder mounted with respect to said frame, a power piston slidably mounted in said power cylinder, a piston rod link operably associated with said power piston, a source of fluid under pressure, a conduit open to said source of fluid under pressure and to the interior of said power cylinder, control means in said conduit for selectively diverting said fluid under pressure to said power cylinder, a first platen section slidably mounted with respect to said frame, a second platen section slidably mounted wtih respect to said first platen section, bias means urging said platen sections together, a master hydraulic unit comprising two master hydraulic components namely a master cylinder and a master piston operably associated with said master cylinder, one of said master hydraulic components being fixedly attached with respect to said one of said platen sections and the other master hydraulic component being operably associated with said piston rod link, at least one slave cylinder mounted With respect to said second platen section, a slave piston operably engaging said first platen section and operably associated with said slave cylinder, there being a passageway open to the interior of said master hydraulic unit and the interior of said slave cylinder, the interior of said master hydraulic unit, the interior of said slave cylinder and said passageway constituting a closed hydraulic system, and means for immobilizing with respect to said frame the platen section located farthest away from said anvil responsive to increase of pressure in said closed hydraulic system.

3. A hydraulic press brake including a main frame, a work anvil mounted with respect to said frame, a hydraulic power cylinder mounted with respect to said frame, a power piston slidably mounted in said cylinder, a piston rod fixedly attached to said power piston, a source of fluid under pressure, a conduit open to said pressure source and to the interior of said power cylinder, control means in said conduit for selectively diverting said fluid under pressure to said power cylinder, a first platen section slidably mounted with respect to said frame, a second platen section slidably mounted with respect to said first platen section, bias means urging said platen sections together, a master cylinder fixedly mounted with respect to one of said platen sections, a master piston operably associated with said master cylinder, means operably connecting said power piston rod and said master piston, at least one slave cylinder fixedly attached with respect to said second platen section, a slave piston operably engaging said first platen section and operably associated with said slave cylinder, there being a passageway open to the interior of said master cylinder and the interior of said slave cylinder, the interior of said master cylinder, said passageway and the interior of said slave cylinder constituting a closed hydraulic system, and means for immobilizing with respect to said frame the platen section located farthest away from said anvil responsive to increase of pressure in said closed hydraulic system.

4. The combination as specified in claim 3 wherein said means for immobilizing said platen section includes brake means fixedly attached with respect to said frame and associated With said platen section, said brake means being operable to hold said section immobile responsive to increase of pressure in said closed hydraulic system.

5. The combination as specified in claim 4 wherein said master cylinder is fixedly mounted with respect to said second platen section and wherein said brake means is associated with said first platen section.

6. The combination as specified in claim 5 and means to prevent a first end of said second platen section from traveling a different distance with respect to said first platen section than a second end of said second platen section.

7. A hydraulic press brake including a main frame, a work anvil mounted with respect to said frame, a hydraulic power cylinder mounted with respect to said frame, a power piston slidably mounted in said cylinder, a power piston rod fixedly attached to said power piston, a source of fluid under pressure, a conduit open to said pressure source and to the interior of said power cylinder, control means in said conduit for selectively diverting said fluid under pressure to the interior of said power cylinder and thereby moving said piston and attached rod toward said anvil, a first platen section slidably mounted with respect to said frame, a second platen section slidably mounted with respect to said first platen section, bias means resiliently urging said platen sections together, a master cylinder located in said second section, a master piston operably engaging said master cylinder, said power piston rod being slidably mounted with respect to said first platen section and operably associated with said master piston, a plurality of slave cylinders fixedly attached with respect to one of said platen sections, a plurality of slave pistons fixedly attached with respect to the platen section not associated with said slave cylinders, each of said slave pistons being operably associated with one of said slave cylinders, therebeing a passageway open to the interior of said master cylinder and the interior of each of said slave cylinders, brake means fixedly attached with respect to said frame and operably associated with said first platen section, a brake cylinder operably associated with said brake means, and a passageway open to the interior of said master cylinder and the interior of said brake cylinder, the interior of said master cylinder,

said passageways, the interior of each of said slave cylin ders and the interior of said brake cylinder constituting a closed hydraulic system, with said brake cylinder positioned to actuate said brake means to hold said first platen section immobile when the pressure within said closed hydraulic system exceeds a predetermined level.

8. The combination as specified in claim 7 and means to prevent a first end of said second platen section from traveling a different distance than a second end of said second platen section with respect to said first platen section.

9. The combination as specified in claim 8 wherein said means to prevent said ends of said second platen section from traveling different distances with respect to said first platen section includes a shaft rotatably mounted with respect to said second platen section, a pinion gear drivingly mounted adjacent each end of said shaft, and a rack fixedly attached with respect to said frame adjacent each end of said shaft and drivingly engaging one of said pinion gears.

10. A hydraulic press brake including a main frame, a Work anvil mounted with respect to said frame, a hydraulic power cylinder mounted with respect to said frame, a power piston slidably mounted in said cylinder, a power piston rod fixedly attached to said power piston, a source of fluid under pressure, a conduit open to said pressure source and to the interior of said power cylinder, control means in said conduit for selectively diverting said fluid under pressure to said cylinder and thereby moving said piston and attached rod toward said anvil, a first platen section slidably mounted with respect to said frame, at least one guide block fixedly attached with respect to said frame, at least one guide rod fixedly attached to said spanner;

first platen section and slidably mounted through said guide block, a second platen section siidably mounted with respect to said first platen section, bias means res'liently urging said second platen section into contacting relationship with said first platen section, a master cylinder located in said second platen section, said power piston rod being slidably mounted through said first platen section with the lower portion of said power piston rod constituted as a master piston operably engaging said master cylinder, a plurality of slave cylinders located in said second platen section, a plurality of slave pistons fixedly attached with respect to said first platen section and each operably associated with one of said slave cylinders, brake means mounted on said guide block and operably engaging said guide rod, a brake actuating cylinder operably associated with said brake means, and therebeing a passageway connecting the interior of said master cylinder, the interior of each of said slave cylinders, and the interior of said brake cylinder in parallel, said passageway and said parallel connected cylinders thereby forming a closed hydraulic circuit, with said brake mean engaging said guide rods and holding said first section of said platen immobile when the pressure within said closed hydraulic system exceeds a predetermined level.

11. The combination as specified in claim 10 wherein said bias means includes a plurality of coil s rings positioned to urge the platen sections together.

12. The combination as specified in claim 10 wherein said brake means includes a pair of brake blocks pivotally attached with respect to said guide block and with respect to each other and substantially encircling said guide rod, said brake cylinder being fixedly attached with respect to a first of said brake blocks and having an internal piston with attached piston rod positioned to operably engage a second of said brake blocks and to move said blocks together to lock said guide rod when the pressure within said closed hydraulic system exceeds a predetermined level.

13. A hydraulic press brake including a main frame, a work anvil mounted with respect to said frame, a power hydraulic unit comprising two power hydraulic components, namely a power hydraulic cylinder and a power piston slidably mounted in said power cylinder, a first of said power hydraulic components being mounted with respect to said frame, a piston rod link operable associated with a second of said hydraulic components, a source of fluid under pressure, a conduit open to said source of fluid under pressure and to the interior of said power cylinder, control means in said conduit for selectively diverting said fluid under pressure to said power cylinder, a first platen section slidably mounted with respect to said frame, a second platen section slidably mounted with respect to said first platen section, bias means urging said platen sections together, a master hydraulic unit comprising two master hydraulic components, namely a master cylinder and a master piston operably associated with said master cylinder, with one of said master hydraulic components being operably associated with said second platen section and the other of said master hydraulic components being operably associated with said piston rod link, at least one slave hydraulic unit comprising two slave hydraulic components, namely a slave cylinder and a slave piston operably associated with said slave cylinder, with one of said slave hydraulic components operably associated with said first platen section and the other slave hydraulic component operably associated with said second platen section, therebeing a passageway open to the interior of said master hydraulic unit and the interior of said slave hydraulic unit, the interior of said master hydraulic unit, the interior of said slave hydraulic unit and said passageway constituting a closed hydraulic system, and means for immobilizing with respect to said frame the platen section located farthest away from said anvil responsive to increase of pressure in said closed hydraulic system.

14. A press brake including a main frame, a work anvil mounted with respect to said frame, a first platen section slidably mounted with respect to said frame, a second platen section slidably mounted with respect to said first platen section, bias means urging said platen sections together, power thrust means mounted with respect to said frame, a piston rod link operably associated with said power thrust means, a master hydraulic unit comprising two master hydraulic components, namely a master cylinder and a master piston operably associated with said master cylinder, one of said master hydraulic components being operably associated with said second platen section and the other of said master hydraulic components being associated with said piston rod link, at least one slave hydraulic unit comprising two slave hydraulic components, namely a slave cylinder and a slave piston operably associated with said cylinder, with one of said slave hydraulic components operably associated with said first platen section and the other slave hydraulic component operably associated with said second platen section, t-herebeing a passageway open to the interior of said master hydraulic unit and the interior of said slave hydraulic unit, the interior of said master hydraulic unit, the interior of said slave hydraulic unit and said passageway constituting a closed hydraulic system, and means for immobilizing with respect to said frame the platen section located farthest away from said anvil responsive to increase of pressure in said closed hydraulic system.

References Cited in the file of this patent UNITED STATES PATENTS 2,302,953 Popock Nov. 24, 1942 2,603,176 Sebring et a1. July 15, 1952 2,855,628 Lassman Oct. 14, 1958