US3190141A - Hydraulic overload safety device - Google Patents

Hydraulic overload safety device Download PDF

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Publication number
US3190141A
US3190141A US20156562A US3190141A US 3190141 A US3190141 A US 3190141A US 20156562 A US20156562 A US 20156562A US 3190141 A US3190141 A US 3190141A
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US
United States
Prior art keywords
pressure
chamber
plunger
cylinder
components
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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English (en)
Inventor
Schlatter Walter
Fischer Max
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MASSEY SCHLATTER AG
Original Assignee
MASSEY SCHLATTER AG
Priority date (The priority date 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 date listed.)
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Publication date
Application filed by MASSEY SCHLATTER AG filed Critical MASSEY SCHLATTER AG
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Publication of US3190141A publication Critical patent/US3190141A/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J13/00—Details of machines for forging, pressing, or hammering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B33/00—Safety devices not otherwise provided for; Breaker blocks; Devices for freeing jammed rolls for handling cobbles; Overload safety devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/0029—Details of, or accessories for, presses; Auxiliary measures in connection with pressing means for adjusting the space between the press slide and the press table, i.e. the shut height
    • B30B15/0035—Details of, or accessories for, presses; Auxiliary measures in connection with pressing means for adjusting the space between the press slide and the press table, i.e. the shut height using an adjustable connection between the press drive means and the press slide
    • 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
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/10—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using liquid only; using a fluid of which the nature is immaterial
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H35/00—Gearings or mechanisms with other special functional features
    • F16H35/10—Arrangements or devices for absorbing overload or preventing damage by overload
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7734—Fluid opened valve requiring reset
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/21—Elements
    • Y10T74/2142—Pitmans and connecting rods
    • Y10T74/2144—Yieldable
    • Y10T74/2148—Automatic release
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/869—Means to drive or to guide tool
    • Y10T83/8719—With transmission yieldable on overload

Definitions

  • the present invention relates to a hydraulic overload safety device comprising in combination: two relatively movable components, a hydraulic cylinder connected to one of said components, ⁇ a plunger slidable in said cylinder in the direction of the relative movement of said two components, said plunger and said movable components dening a chamber therebetween, a hydraulic fluid in operation lling the chamber bounded by the end of said plunger and said cylinder, said cylinder havingA a wall with a central aperture and said plunger having a neck portion passing with ample clearance through said aper- ⁇ ture and a valve head on said neck portion beyond said aperture normally contacting an inner or outer end face of said cylinder Wall adjacent said aperture forming a valve seat for said valve head, and an external source of hydraulic pressure in communication with said cylinder chamber, and in operation setting up a preloading pressure therein which keeps said valve head tightly on said valve seat as long as the pressure set up by theforce
  • FlG. 1 is a longitudinal section of arhydraulic safety device arranged on the carriage of a mechanical press, in the normal position;
  • This pre-loading pressure may amount e.g. to
  • the pump is of each character that it precludes back-flow of uid.
  • the spindle 5 is pulled downwardly by the plunger 3, so that the head 8 of the spindle contacts firmly and tightly the outer face 9 of the cylinder end wall 6, and accordingly no oil can emerge from the space 12 through the annular gap 14, which exists between the cylinder bottom 6 and the spindle 5, which in this region does not carry a screw thread.
  • the head 8 of the spindle is arranged within a cap 15, which is connected with the carriage 1 and the cylinder 2 to a rigid unit in a manner not illustrated in detail.
  • 'Ihe head 8 of the spindle is provided on top with an internal toothing 16, which meshes with a pinion 17, mounted on a shaft 188 which is journalled in the cap 15 and passes through the same, and which carries another pinion 19 externally of the cap 15, Vwhich may be driven in a manner not illustrated in detail'in order toturn theY spindle V5 and thereby to adjust the plunger 3 with respect to the cylinder 2.
  • the Vadjustment stroke of the plunger 3 is In the lower part of the cavity 22 of the cap 15 there is contained a small oil reserve 23, on top of which a slight air excess pressure, of for example 2 atmospheres gauge,
  • FIG. 2 is a corresponding section, but after the response of the safety device.
  • FIG. 3 is a longitudinal section of a modified safety device.
  • FIG. l the ⁇ partly illustrated carriage of a mechanical press is denoted.
  • the carriage 1 is moved up and down by means of an eccentric mechanism with respect -to a stationary tool support; these components of the press are not illustrated, since theyare well known.
  • a cylinder 2 is lxed, in the interior of which a hollow plunger 3 is slidable, which has aniinternal screw thread 4 and is screwed on an adjustmentspindle 5.
  • the spindle .5 passes through anopening 7 providedin the end wall 6 of the cylinder, and has a headr8, which normally contacts the outer face 9 of the cylinder-end wall 6.
  • the oil is supplied to the cylinder space 12 through an oil pipe 13
  • the device described operates; as follows: When during the working strokev of the carriage 1 the force arising between the tools and the Work piece to be pressed does not exceed a predetermined limit, which is proportional to the pre-loading pressure, the plunger 3 moves as a rigid unit together with the carriage 1 and the components connected therewith.
  • valve head-*of which is'loaded,-e.g., by means of a spring,.does not howeverwork so abruptly as thevalve 8, 9, sinceits valve head is subjectrto the bias ofthe spring Vforcing it towards .itsfclo'sed .position even. after the response pressurehas. been reached.
  • Other ⁇ known valves likewisedo -not operateouicklyenough ,for the ,present purpose. It is accordingly very diicultwith-the'known devices tol pass duringavery short.period.of,.e.g., /o, of
  • the duct 26 facilitatestheepasf sage of the oilfrom one chamberlto'the other, whenthe spindle iis ⁇ 'drivenby means of theV pinion 19 VV for the 1 adjustment ofthe plunger-3.
  • thev duct'2r6 has ⁇ the eiect that Yupon responseof. the .safetykdevice the pressuref drops very rapidly also inthe .interior 25 .of the plunger, andfaccordinglygalso the. friction .between thef i ⁇ plunger and "the fcylinderlwalliis reducedgimmediately
  • the ductf26 may Vnaturally beprovidedalternatively in th'espind1e5.if, ⁇ l. Y
  • Y 2a is guided; Aplung'enjwhich is slidable inthe cylinder ⁇ 2a, is provided .with V,a head 8a serving-as a valve head,
  • the cylinder Za is not j openon Vits end oppositeits wall 6a, jbutis. closed -by-a Y Y fulllower Vend -WallSwL and at its lowerend face 21a a toolk holder (not shown) for1.apress 'tool' is mounted.
  • The, ⁇ lother press tool is naturally mountedzon the stationarytool supports;towardsgwhich the carriage-1, which constitutes .i the movable,V tool support, moves during i-tsworking stroke;
  • the cylinder space. .12a is lledwitheoil, whichk is supf plied toit throughfa central :bore-34o of the ⁇ plunger. 3d.
  • the bore 34a is :fed through a pressure oil pipe-13u11from,V
  • a high pressure pump 35a for.e.g.1l000 atmospheres gauge:
  • the pump 35o is of such a characterthat it pre-VK cludes back-flow of f fluid.
  • the oil reservoir 23a is bounded by the .bushing 6a, .-a conical end Vface 37a ofthe'l cylinderY Zarand a, skirt Sprojectinggupwardly ,from-.the f same.
  • UThe, plunger I3oz has ,an ,upper .portion .Soon which is 15a and carrying another pinion'lfal externally of the capL 15a, which may be drivenfin order :to turn ⁇ the nut 39a and of the 'press tools;k I f Adjacent 1 the lower end face Qof; the4 head 4.rzy of, the
  • the plungera has-1an f i annular shoulder Sfoon which bears the V.upper end of 7 av comparatively weakY spring 4211,'.Which'abutsbelow thei fbottorn vof the cylindersA
  • the head iizLof ⁇ the plunger p has a lcylindrical'gmain por-tionASa, fthe diameter of which Y issmallerthan the inner, diameter of the'cylinder .Zalf
  • tween Ythe tools'and the -vvorrlrv pieceto bepressed doesnot exceed .a pre-determined pre-loadingpressure of e.g. 1000 atmospheres gauge prevailing in the cylinder space 12, .the cylinder 2 with the carriage 1 moves downwardly, the pressing force being transmitted to the cylinder 2a from the carriage 1 through the caplSa, the nut 39a, the plunger 3a and the pressure oil contained in the cylinder space 12a.
  • the cylinder 2a slides slightly upward with respect to the piston 3a, so .that the valve 8a, 9a opens, and oil flows from the cylinder chamber 12a, through the annular lgap 14a into the oil reservoir 23a. lConsequently the pressure drops in the cylinder chamber 112, so that the cylinder 2a moves abruptly upwardly into the position 2' indicated in chain-dotted lines, almost the whole of the oil contained .in the cylinder chamber 12a flowing extremely rapidly into the oil reservoir 23a.
  • the spring 42 abiases the cylinder 2a away from the head 8a of the plunger, so that the oil flows back through the open valve 8a, 9a into the cylinder chamber 12a, and after the closing of the valve 8a, 9a, the Vhighpressure pump ⁇ 35a restores the pre-loading pressure desired.
  • an accumulator may be provided, which may for example be constructed as a pressure multiplier;
  • the present embodiment has the advantage, that no seal has to be providedin order to prevent a leakage of the pressure 4oil from the cylinder chamberllZa.
  • the plunger has In the em-V a sliding surface guided on the inner wall surface of the cylinder, and along this sliding surface leakage of the pressure oil from the cylinder would be possible, or such a leakage has rto be preventedV by special measures, e.g. by providing piston rings, lwhich owing Ato the hi-gh oil pressure is a delicate task.
  • a further advantage of the present device is that for ⁇ the same limit of the pressing force, the cylinder 2a can be kept smaller than that of the device according to the FIGS. 1 and 2.
  • the safety device according to FIG. 3 is likewise applicable not only to presses but also to other Y machines, e.g. rolling mills.
  • FIG. 3 a modification is indicated, according toV which the oil reservoir 23a is closed on top by an Vannular cover plate 44a indicated in chain-dotted lines, which is sealed against the plunger 3a by means of a seal (not shown) ⁇ for example inserted into an annular groove, and by a further seal (likewise not shown) against the internal flange 41a.
  • a pipe 45a indicated by a .single chain-dotted line issues immediately below the cover plate 44 into the oil reservoir 23a, which includes in this case moreover a small space existing above the skirt 38a in the interior of the carriage 1.
  • the pipe 45a may be supplied from a source 46a with a fluid, for example air or oil under a comparatively low pressure, of i.e.
  • the low-.pressure oil pump feeding oil continuously into the container until the prescribed p pressure is attained therein, whereafter the pump is switched off or is made to work idly over a by-pass valve.
  • an observation glass may be provided for indicating the oil ⁇ level in the oil reservoir 23a.
  • a hydraulic overload safety device comprising in combination: two relatively movable cylinder components, a hydraulic chamber in one of said components, a plunger carried by one of said components and movable in saidr chamber in the direction of the relative movement of said two components, said chamber .being delined by said plunger and said movable components, ⁇ a hydraulic pressure uid from an external source of hydraulic pressure in operation iilling the space' in said chamber, vsaid chamber having a wall provided ⁇ with a.
  • valve head means lfor subjecting said movable cylinder components to external forces, and an external source of hydraulic pressure in communication with said chamber and in operation setting up a preloading pressure therein which keeps said-valve head tightly on said valve seat as long as the pressure set up by the external forces between said relatively movable cylinder components is below said preloading pressure, and allows said valve head Vto be lifted olf said valve.
  • seat and Yto rapidly discharge said hydraulic uid in said chamber past said neck portion when external forces generates a pressure exceeding a predetermined pressure limit of said preloading pressure.
  • one of said components has a hollow portion with an internal screw thread, and comprising a threaded plunger screwed intoVV said internal screw thread and forming said neck portion carrying said Vvalve head, said valve head contacting an outer face of said cylinder wall serving as said valve seat.
  • a device as claimed in'claim 3 comprising a cap iixedly connected to a cylinder forming said chamber outside said apertured chamber wall, said valve head being located between said cap and said chamber wall, and the space between said cap and said chamber wall containing pressure loaded hydraulic iiuid.V Y
  • a device as claimed in claim 5, comprising an external source of compressed air in communication with said space between said cap and said cylinder wall.
  • a device as claimed in claim'S comprising a toothed gearing in driving connection with said threaded plunger, and capable of adjusting the axial position of said plunger relativeV to said chamber by turning said threaded spindle in said internal screw thread of said plunger.
  • valve seat for said .valve head means forA subjecting said movablel components to externalttforces, and in externalv source of hydraulic pressure in communication with said Y chamber and in operation settinguup a preloadngpres- Y sure therein which keeps said valve Vhead tightly onsaid Y valve seat as long .as :the pressure ⁇ setup bythe external forces between said relatively movable.
  • cylinder components is below said'preloa'ding pressure,.and allowsfsaid a/alve head tobe lifted ol said rvalve seat and to rapidly ⁇ Y discharge said hydraulic uid pastsaid neel; portion when said external forces generates a pressure further compressl ing the pressureload'ed hydraulic uid until said external -V forces exceed a predetermined pressure limit.
  • said external source ofhydraulicpressure andwith theV cylinder space bounded'between saidvalvejhead andA K plunger hasA an externally screw-threadedV portion,and
  • a device as claimed inclaimV lfcomprising a duid level indicator in communication with said fluid reservoir.
  • a hydraulic overload safety device comprising inner' and outer relatively movable! cylinder components, a 'restricted walllportion formedin' one of said components, aj plunger Vadjustably mounted in the other of said .cylin- Y der components projecting througlranY aperture in said.
  • aperture in said wall portion being of a diameterslightlyf greater than ⁇ said plunger togprovide a clearance space.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Safety Valves (AREA)
  • Control Of Presses (AREA)
US20156562 1961-06-13 1962-06-11 Hydraulic overload safety device Expired - Lifetime US3190141A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH688161A CH386783A (de) 1961-06-13 1961-06-13 Hydraulische Überlast-Sicherungsvorrichtung
CH127362A CH394724A (de) 1961-06-13 1962-02-02 Hydraulische Überlast-Sicherungsvorrichtung

Publications (1)

Publication Number Publication Date
US3190141A true US3190141A (en) 1965-06-22

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US20156562 Expired - Lifetime US3190141A (en) 1961-06-13 1962-06-11 Hydraulic overload safety device

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US (1) US3190141A (de)
CH (2) CH386783A (de)
GB (1) GB944780A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3892143A (en) * 1972-08-26 1975-07-01 Krupp Gmbh Pitman adjustable in length for a press with hydraulic overload safety mechanism
US3951025A (en) * 1974-09-17 1976-04-20 Eastman Kodak Company Overload safety device
US4166415A (en) * 1978-04-21 1979-09-04 Gulf & Western Manufacturing Company Press having overload responsive slide shut height adjusting mechanism
US20040003730A1 (en) * 2002-06-28 2004-01-08 Schuler Pressen Gmbh & Co. Kg Overload safety device in a press

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112178003B (zh) * 2020-09-16 2023-07-21 马鞍山钢铁股份有限公司 平整机弯辊缸工作辊锁紧装置及其装配方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US903424A (en) * 1907-02-21 1908-11-10 Bliss Co Pressure-limiting device.
US2396815A (en) * 1942-11-05 1946-03-19 Sf Bowser & Co Inc By-pass valve mechanism
US2491279A (en) * 1947-06-25 1949-12-13 Dayton Rogers Mfg Co Safety overload pitman for power presses
US2616543A (en) * 1949-03-19 1952-11-04 Danly Mach Specialties Inc Safety assembly for power presses
US2936055A (en) * 1956-10-03 1960-05-10 Verson Allsteel Press Co Overload protected mechanical press
US2937733A (en) * 1956-10-31 1960-05-24 Danly Mach Specialties Inc Overload relief assembly for power presses
US2983176A (en) * 1956-08-21 1961-05-09 Tayco Dev Stripper construction for a perforator

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US903424A (en) * 1907-02-21 1908-11-10 Bliss Co Pressure-limiting device.
US2396815A (en) * 1942-11-05 1946-03-19 Sf Bowser & Co Inc By-pass valve mechanism
US2491279A (en) * 1947-06-25 1949-12-13 Dayton Rogers Mfg Co Safety overload pitman for power presses
US2616543A (en) * 1949-03-19 1952-11-04 Danly Mach Specialties Inc Safety assembly for power presses
US2983176A (en) * 1956-08-21 1961-05-09 Tayco Dev Stripper construction for a perforator
US2936055A (en) * 1956-10-03 1960-05-10 Verson Allsteel Press Co Overload protected mechanical press
US2937733A (en) * 1956-10-31 1960-05-24 Danly Mach Specialties Inc Overload relief assembly for power presses

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3892143A (en) * 1972-08-26 1975-07-01 Krupp Gmbh Pitman adjustable in length for a press with hydraulic overload safety mechanism
US3951025A (en) * 1974-09-17 1976-04-20 Eastman Kodak Company Overload safety device
US4166415A (en) * 1978-04-21 1979-09-04 Gulf & Western Manufacturing Company Press having overload responsive slide shut height adjusting mechanism
US20040003730A1 (en) * 2002-06-28 2004-01-08 Schuler Pressen Gmbh & Co. Kg Overload safety device in a press
US7024991B2 (en) * 2002-06-28 2006-04-11 Schuler Pressen Gmbh & Co. Kg Overload safety device in a press

Also Published As

Publication number Publication date
CH386783A (de) 1965-01-15
CH394724A (de) 1965-06-30
GB944780A (en) 1963-12-18

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