US3481171A - Multiple overload press protection device and adjustable press tonnage device - Google Patents
Multiple overload press protection device and adjustable press tonnage device Download PDFInfo
- Publication number
- US3481171A US3481171A US646345A US3481171DA US3481171A US 3481171 A US3481171 A US 3481171A US 646345 A US646345 A US 646345A US 3481171D A US3481171D A US 3481171DA US 3481171 A US3481171 A US 3481171A
- Authority
- US
- United States
- Prior art keywords
- press
- pressure
- overload
- fluid
- switch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B30—PRESSES
- B30B—PRESSES IN GENERAL
- B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
- B30B15/28—Arrangements for preventing distortion of, or damage to, presses or parts thereof
- B30B15/281—Arrangements for preventing distortion of, or damage to, presses or parts thereof overload limiting devices
- B30B15/284—Arrangements for preventing distortion of, or damage to, presses or parts thereof overload limiting devices releasing fluid from a fluid chamber subjected to overload pressure
Definitions
- This invention relates to power presses and more particularly to an overload protection device for such presses.
- overload devices which are designed to discontinue operation of the press when an overload condition occurs.
- these prior art devices have been incorporated either in the slide assembly of the press, the press tie rods or in the bed of the press.
- These overload systems are usually of a hydraulic nature with the compression of hydraulic fluid above a certain predetermined level signalling the presence of an overload condition and a relief valve is then actuated to vent the hydraulic fluid while, simultaneously, the drive system of the press is deactivated.
- I is an object of this invention to provide an improved press protection system.
- the primary object of this invention is to provide a multiple overload press protection device.
- a further object of this invention is the provision of an overload sensing system which may be employed to sense the presence of an overload at any point in the press stroke without limiting the utilization of the full rated tonnage of the press.
- Another object of the invention is to provide an overload sensing system which is effective to sense the pressure of an overloaded condition at a plurality of points in the press stroke.
- a further object of the invention is to provide a system which may be used to adjust the maximum tonnage developed by the press and may also be used to provide an overload protection for the press during various stages of the press stroke.
- the other hydraulic pressure sensitive switches are set at various pressure levels which correspond to the particular press tonnage desirably developed at various stages of the press stroke. These latter switches are actuated by cams in the press cam limit switch with each pressure switch being controlled by a separate cam so that each switch is operative only during a predetermined portion of the press cycle. When a particular switch is operable, and if an overload condition is present, the switch actuates the solenoid valves to vent the system and discontinue operation of the press. Any number of pressure switches may be employed thereby providing accurate control over the stresses imposed on the press throughout its operating cycle.
- FIGURE 1 is a diagrammatic view of the various components of the hydraulic system comprising the present invention.
- FIGURE 2 is a schematic diagram of a representative electrical circuit useable with the hydraulic system of the instant invention.
- FIGURE 1 there are illustrated a pair of substantially conventional slide mechanisms for a power press, indicated generally by the reference numeral 10. These slide mechanisms are adapted to be employed in a press of a conventional construction as will be understood by those having ordinary skill in this art.
- Each slide includes a lower portion 11 adapted to support a die member and a slide adjustment assembly which includes cylinder member 12.
- the cylinder includes a central opening 13 with a cylindrical intermediate member 14 connected, as by bolts, to the cylinder 12.
- a sleeve 15 is secured by bolts to the member 14.
- a pitman or connecting rod 16 is secured by a wrist pin 17 to a connection wrist 18.
- connection wrist has a Sliding fit with the sleeve 15 and includes a threaded extension 19 which is threaded in engagement with a nut 20.
- the nut 20 is driven by a worm gear 21 which in turn is rotated by a screw 22 carried in the cylindrical member 14. It will be appreciated that as the screw 22 is rotated, the nut 20 is also rotated causing the connection wrist 18 to be displaced along the length of the sleeve 15.
- This mechanism which is essentially conventional in construction, normally comprises the slide and slide adjustment mechanism found in many presses.
- the connecting rod 16 is adapted to be actuated by a crank shaft 25 (the interconnection not being shown) in a manner well known in the art.
- the crank shaft 25 is driven by an appropriate source of power which is connected through a clutch arrangement to the crank shaft.
- a piston 26 Incorporated in the cylindrical recess 13 in the slide adjustment assembly is a piston 26.
- the piston is reduced in diameter at its upper portion 27 to fit within the cylindrical member 14.
- a central recess 28 in the piston accommodates the extension 19 of the connection wrist 18.
- the piston is so dimensioned that when the upper portion 27 of the piston is in engagement with the nut 20, the lower surface 29 of the piston is spaced from the bottom wall 30 of the recess 13, thereby defining a fluid chamber 34 between the piston 26 and the member 12.
- Appropriate seals 31 may be carried by the piston 26 as well as the cylindrical member 14.
- the member 12 further includes entrance and exit ports 32, 33 are in communication with the fluid chamber 34 with the ports being adapted to be connected to fluid lines as will be more fully hereinafter described.
- the above described mechanism thus defines a fluid chamber in which hydraulic fluid may be subjected to pressure as the press is operated. It will be appreciated that the pressure created on the hydraulic fluid may be used as a means for sensing an overload condition.
- the fluid chamber 34 in which the fluid is placed has been described in connection with a slide mechanism, it is to be understood that the present invention is not restricted to a slide mechanism and may be incorporated in any portion of the press that is subjected to loading throughout the cycle of operation of the press.
- a source of hydraulic fluid, indicated at 50, is available for the system.
- This fluid is passed through a filter 51 and supplied under pressure to the system by a pump 52.
- the pump may be either air or electric operated.
- the fluid is supplied through a line 53 with a gauge 54 indicating the pressure level.
- the fluid passes through a check valve 55 and into the fluid chamber 34.
- two cylinders are supplied with fluid by the same system but it will be appreciated that either more or less than that number of cylinders may be employed.
- a fluid line 57 is connected to the outlet port 33 and this line is connected to a relief valve 58.
- a similar relief valve 59 is connected to a fluid line which is in fluid communication with the fluid chamber in the other of the slide mechanisms.
- Both relief valves 58 and 59 are preset to vent fluid in lines 57 and 60 only above a predetermined level of pressure. This pressure ordinarily is somewhere near the maximum tonnage for which the press is rated plus a certain percent of overload.
- a vent line 61 is common to both valves 58, 59 with a solenoid valve 62 and a further solenoid valve 63 in fluid communication with the line 61.
- the solenoid valve 62 is normally closed and is opened only when the solenoid 64 is energized.
- the valve 63 is normally closed when the solenoid 66 is energized and opened when solenoid is energized.
- the valves 62 and 63 may operate in the reverse manner and be normally open with energization of the solenoids holding the valves closed.
- the arrangement here illustrated is only by way of example and the relationship between the normally open or normally closed position and energization of the solenoids may be varied depending on the electrical circuit used as well as other factors.
- the relief valves 58, 59 are of a conventional balanced piston construction such as a Vickers valve and it is believed that a detailed description of their working mechanism is unnecessary. Although, two such relief valves have been illustrated, it is to be understood that a different number of relief valves may be employed and the number which may be used with any particular system is not limited.
- One such pressure switch 70 is used as a preload pressure switch with another pressure switch 71 serving as a full overload tonnage pressure switch.
- pressure switches 72, 73, 74 all of which are in fluid communication with line 53.
- the pressure switches 72, 73, 74 are set for various pressures which correspond to the maximum press tonnage suitable for a particular portion of the press stroke.
- Each of the pressure switches is controlled by a separate cam 75, 76, 77 which are a part of the press cam limit switch mechanism.
- cams may control the switches in various ways, such as shown in FIGURE 2.
- These cams rotate on a one-to-one ratio with the press crank shaft 25 so that the cams are precisely timed to the operation of the press.
- the cams are such that they may be adjusted on the cam shaft 78 in the event that the timing is to be adjusted.
- the cams control the operation of the pressure switches 72, 73, 74, so that each switch is operative only during a predetermined portion of the press cycle.
- FIGURE 2 is a schematic diagram of an electrical circuit which may be used with a system such as that hereinabove described. Only one pressure switch 72 is shown in this circuit in addition to the full overload pressure switch 71 but it will be appreciated that a similar circuit arrangement would be employed for the pressure switches 73, 74.
- the circuit shown in FIGURE 2 illustrates the condition of the components when the press is stopped and the slide is at the top of its stroke.
- a pair of relays are illustrated with the first relay having a coil CRl-C in line 1, normally closed contacts CR1-1 in line 5 and normally open contacts CR1-2 in line 10.
- the other relay has a coil CR2-C in line 4 with normally open contacts CR2-1 in line 1, CR2-2 in line 3 and CR23 in line 6.
- the second relay further includes normally closed contacts CR2-4 in line 7 and CR2-5 in line 11.
- a preload light L1 is in line 2 and an overload light L2 is in line 5.
- a cam limit switch CLS-l is in line 3 and a second cam limit switch CLS-2 is in line 4.
- the circuit further includes a manual selector switch and a manual stop button as is conventional.
- the cam limit switch CLS-1 is controlled by a cam on the cam shaft which may be adjusted to operate to close the switch when the slide is a predetermined distance up from the bottom of the stroke through 270. With the switch CLS-l closed, the pressure switch 72 is rendered inefiective and the presence of an overload in the system is sensed only by the pressure switch 71.
- the pressure switch 71 is actuated, the light L2 signals the presence of the overload, the relay coils CRl-C and CR2-C are de-energized and the various relay contacts are returned to their original position stopping the press.
- the pressure switch 72 is actuated with the limit switch CLS-l open.
- the press with the overload system hereinabove described operates in the following manner.
- the pump 52 is operated and fluid is drawn from the tank and introduced through line 53 to the fluid chambers 34 in the slide mechanisms 10.
- the preload switch 70 is set to be actuated after a predetermined fluid pressure build up has occurred. When this pressure level has been achieved the switch 70 is closed energizing coil CRl-C and closing contact CR1-2 thereby actuating the clutch and brake circuit. Also coil CR2-C is energized which results in the energization of solenoid 66 and the deenergization of solenoids 64 and so that the valves 62 and 63 are closed. Operation of the press may then commence.
- the cams controlling the pressure switches 72, 73, 74 are operative to actuate each of the cams sequentially at the appropriate predetermined portion of the stroke.
- the pressure switch will sense the overload condition and the switch will be opened. The opening of the switch will de-energize coil CR2-C causing contact CR2-4 to be closed and the solenoids 64, 65 to be energized. The energization of the solenoids 64,
- valve 65 opens valves 62, '63 and thence line 61 to reduce the hydraulic pressure in the line to close to zero.
- an unbalanced condition exists between line 61 and lines 57 and 60 causing the relief valves 58, 59 to become unbalanced.
- the relief valves open to relieve the pressure in the overloaded cylinders.
- the pressure switch opens, de-energizing coil CRl-C which opens contact CR1-2 and the press is stopped.
- the hydraulic pressure switch 71 will be opened and the hydraulic and electric circuits will be operated in the above described manner to vent the hydraulic fluid from the overloaded cylinders and the press will be stopped.
- the full tonnage pressure switch 71 is not con- 75 trolled by any cam since its function is to operate solely at a predetermined point in the stroke, that is, at or near the bottom.
- the invention is not limited to any particular type of valve or any particular number of valves in the hydraulic system.
- the invention requires merely a hydraulic system in which means are available to vent the system when an overload condition at any predetermined point in the cycle is signaled and the particular method of achieving the venting of the system may vary widely.
- the press tonnage can be adjusted up to the maximum rated tonnage of the press.
- a press protection system for sensing the presence of an overload condition in a press, said press including force applying means, first and second members defining a fluid chamber therebetween and means subjecting said first and second members to loading over a predetermined cycle by said force applying means, the system comprismg:
- venting means in the fluid system operative to vent the system when actuated
- control means operatively connected to said sensing means to render said sensing means operative only during a predetermined portion of the cycle of said force applying means.
- said pressure sensing means comprises a pressure actuated switch
- venting means including solenoid actuated valve means
- said relief valve means being interposed in the system between said fluid chamber and said solenoid valve means;
- said additional sensing means being independent of said control means and operative to actuate said venting means whenever the pressure in the system exceeds a predetermined level.
- venting means including solenoid actuated valve means
- venting means further includes relief valve means in the fluid system bydraulically isolating said solenoid valve means from said fluid chamber.
- venting means includes a plurality of valves
- said additional sensing means being operative to actuate at least one of said valves when the pressure in said system reaches a predetermined level.
- said pressure sensing means comprises a plurality of pressure actuated switches
- each of said switches being operable at a diflYerent level of pressure and only during a predetermined portion of the cycle of said force applying means.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Control Of Presses (AREA)
Description
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US64634567A | 1967-06-15 | 1967-06-15 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3481171A true US3481171A (en) | 1969-12-02 |
Family
ID=24592690
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US646345A Expired - Lifetime US3481171A (en) | 1967-06-15 | 1967-06-15 | Multiple overload press protection device and adjustable press tonnage device |
Country Status (3)
Country | Link |
---|---|
US (1) | US3481171A (en) |
FR (1) | FR1570183A (en) |
GB (1) | GB1172954A (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3583201A (en) * | 1969-01-29 | 1971-06-08 | Gulf & Western Products Co | Hydraulic overload bolster |
US3817080A (en) * | 1971-04-07 | 1974-06-18 | B Zupan | Safety-bolster |
US3825811A (en) * | 1973-02-26 | 1974-07-23 | Aluminum Co Of America | System and method for monitoring a press load |
US3955396A (en) * | 1974-10-11 | 1976-05-11 | Gulf & Western Manufacturing Company | Press overload protection system |
US4030336A (en) * | 1976-07-09 | 1977-06-21 | Anatoly Sergeevich Grigorenko | Hydraulic protection device for presses |
US5125332A (en) * | 1991-01-09 | 1992-06-30 | Brothers Industries, Inc. | Non-destructive overload apparatus for a mechanical press |
US5638748A (en) * | 1996-01-25 | 1997-06-17 | The Minster Machine Company | Hydraulic overload proportional valving system for a mechanical press |
US20030046970A1 (en) * | 2000-09-23 | 2003-03-13 | Juergen Fahrenbach | Press for transforming work pieces |
CN100560245C (en) * | 2008-08-13 | 2009-11-18 | 中国第一重型机械股份公司 | Water press large-pressure instant load-missing control method |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2358269A (en) * | 1939-12-05 | 1944-09-12 | Wemhoner Wilhelm | Machine tool and the like |
US2382046A (en) * | 1942-02-23 | 1945-08-14 | Hydraulic Dev Corp Inc | Hydraulic press |
US2382041A (en) * | 1941-03-01 | 1945-08-14 | Hydraulic Dev Corp Inc | Turret press |
US2569034A (en) * | 1948-05-20 | 1951-09-25 | Champlain Company Inc | Hydraulic impression gear for printing presses |
-
1967
- 1967-06-15 US US646345A patent/US3481171A/en not_active Expired - Lifetime
-
1968
- 1968-06-11 GB GB27647/68A patent/GB1172954A/en not_active Expired
- 1968-06-14 FR FR1570183D patent/FR1570183A/fr not_active Expired
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2358269A (en) * | 1939-12-05 | 1944-09-12 | Wemhoner Wilhelm | Machine tool and the like |
US2382041A (en) * | 1941-03-01 | 1945-08-14 | Hydraulic Dev Corp Inc | Turret press |
US2382046A (en) * | 1942-02-23 | 1945-08-14 | Hydraulic Dev Corp Inc | Hydraulic press |
US2569034A (en) * | 1948-05-20 | 1951-09-25 | Champlain Company Inc | Hydraulic impression gear for printing presses |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3583201A (en) * | 1969-01-29 | 1971-06-08 | Gulf & Western Products Co | Hydraulic overload bolster |
US3817080A (en) * | 1971-04-07 | 1974-06-18 | B Zupan | Safety-bolster |
US3825811A (en) * | 1973-02-26 | 1974-07-23 | Aluminum Co Of America | System and method for monitoring a press load |
US3955396A (en) * | 1974-10-11 | 1976-05-11 | Gulf & Western Manufacturing Company | Press overload protection system |
US4030336A (en) * | 1976-07-09 | 1977-06-21 | Anatoly Sergeevich Grigorenko | Hydraulic protection device for presses |
US5125332A (en) * | 1991-01-09 | 1992-06-30 | Brothers Industries, Inc. | Non-destructive overload apparatus for a mechanical press |
US5638748A (en) * | 1996-01-25 | 1997-06-17 | The Minster Machine Company | Hydraulic overload proportional valving system for a mechanical press |
US6662617B2 (en) * | 2000-09-12 | 2003-12-16 | Schuler Pressen Gmbh & Co. Kg | Press for transforming work pieces |
US20030046970A1 (en) * | 2000-09-23 | 2003-03-13 | Juergen Fahrenbach | Press for transforming work pieces |
CN100560245C (en) * | 2008-08-13 | 2009-11-18 | 中国第一重型机械股份公司 | Water press large-pressure instant load-missing control method |
Also Published As
Publication number | Publication date |
---|---|
GB1172954A (en) | 1969-12-03 |
FR1570183A (en) | 1969-06-06 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: E.W. BLISS COMPANY, INC.,, DELAWARE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:GULF & WESTERN INDUSTRIAL PRODUCTS COMPANY A CORP OF DE;REEL/FRAME:004204/0264 Effective date: 19831110 Owner name: E.W. BLISS COMPANY, INC., DE. A CORP OF DE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:GULF & WESTERN INDUSTRIAL PRODUCTS COMPANY A CORP OF DE;REEL/FRAME:004204/0264 Effective date: 19831110 |
|
AS | Assignment |
Owner name: BARCLAYS AMERICAN/BUSINESS CREDIT, INC., CONNECTIC Free format text: SECURITY INTEREST;ASSIGNOR:E.W. BLISS COMPANY;REEL/FRAME:005880/0330 Effective date: 19880915 |
|
AS | Assignment |
Owner name: SHAWMUT CAPITAL CORPORATION, CONNECTICUT Free format text: SALE/TRANSFER OF SECURITY INTEREST TO A NEW SECURED PARTY;ASSIGNOR:BARCLAYS BUSINESS CREDIT, INC.;REEL/FRAME:007644/0215 Effective date: 19950130 |