US3892143A - Pitman adjustable in length for a press with hydraulic overload safety mechanism - Google Patents

Pitman adjustable in length for a press with hydraulic overload safety mechanism Download PDF

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Publication number
US3892143A
US3892143A US392022A US39202273A US3892143A US 3892143 A US3892143 A US 3892143A US 392022 A US392022 A US 392022A US 39202273 A US39202273 A US 39202273A US 3892143 A US3892143 A US 3892143A
Authority
US
United States
Prior art keywords
pitman
pressure
press
pressure chamber
sleeve
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
Application number
US392022A
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English (en)
Inventor
Heinz Kleister
Walter Sommer
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.)
Fried Krupp AG
Original Assignee
Fried Krupp 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.)
Filing date
Publication date
Application filed by Fried Krupp AG filed Critical Fried Krupp AG
Application granted granted Critical
Publication of US3892143A publication Critical patent/US3892143A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • 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
    • 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
    • Y10T74/2147—Fluid cushion
    • 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

Definitions

  • Shoemaker Attorney, Agent, or Firm-Walter Becker 5 7 ABSTRACT A hydraulic overload safety device with a pitman adjustable in length for a press, in which the liquid pressure assuring the press against overload at the same time tightens the screw connection between two threadedly interengaged sections of the pitman and normally keeps them firmly secured to each other during normal operation of the press while this connection is automatically disengaged in response to the pitman encountering an overload.
  • the present invention relates to a pitman adjustable in length for a press or similar machine tool with the hydraulic overload safety mechanism.
  • Presses have to meet the requirement that the smallest distance between the ram and the press table must be adjustable so as to adapt the same to the dimensions of the respective tool and workpiece.
  • presses Inasmuch as pressing tools are relatively expensive, presses have to meet further requirement, namely that they comprise a safety mechanism which will safeguard the tool against damage or destruction in case of an overload.
  • An overload may occur, for instance, with cap or lid punch presses when a ronde or disc is introduced into the tool before the last punched cap or lid has left the range of the too].
  • Such overload safety mechanism also protects the machine frame and driving elements against undesired stresses.
  • the adjustability as to the length of the pitman is customarily realized by making the pitman of two parts which are interconnected by means of an axial screw thread. By turning one part relative to the other part, the effective length of the pitman can be changed.
  • breakers and breaker discs For protection against overload, several solutions are known, such as breakers and breaker discs, flywheel circuits, circuit including springing of the frame, difference in current of the drive motor, electronic sensing of the coasting parts, as well as hydraulic overload mechanisms of various types, according to which the pressing force is conveyed by means ofa piston moving against the liquid pressure or by means of an opening valve.
  • the pitman adjustable as to length and the hydraulic overload safety mechanism according to the present invention are characterized primarily in that the hydraulic overload safety mechanism is arranged in the pitman in such a way that the liquid pressure which brings about the overload protection simultaneously tightens the screw connection which serves for the adjustment as to length of the pitman and effects such tightening during the operation of the press and thereby secures the screw connection in the two-part pitman by a frictional engagement.
  • the pitman is composed of a plurality of parts two of which are axially displaceable relative to each other and move toward each other when the adjustable liquid pressure is exceeded in a pressure chamber which is located in one of the two parts while the liquid pressure and together therewith the force conveyed to the tool is being reduced.
  • the liquid pressure through the intervention of parts located in the pitman housing and movable relative thereto, tightens the screw thread which serves for longitudinally adjusting the pitman, the screw thread establishing in interengagement of the parts of the pitman which are rotatable relative to each other, so that this screw thread will be frictionally secured.
  • the liquid pressure is generated by pump which is adapted to be controlled respect to its pressure. In this way the permissible maximum force can be set in conformity with the requirements of the respective tool and material.
  • the drawing illustrates a vertical section through a pitman with the pertaining control elements.
  • the introduction of power is effected by the eccentric 1 of the crank-shaft through the pitman onto the ram 9.
  • the pitman is composed primarily of two groups of parts which are axially displaceable partially against each other.
  • One group comprises the pitman housing 2 which has a central bore 2a that opens in downward direction and is provided at one end with a screw thread 2b.
  • This group furthermore comprises a sleeve 4 which is slidable in the central bore 20 and is provided with a high pressure seal 3.
  • Sleeve 4 rests on a pressure spindle 5 which is longitudinally adjustably connected through the screw thread 2b with the connecting rod housing 2.
  • the other group comprises a sealing member 6 and a connecting rod 7 which is firmly connected to the sealing member 6.
  • the connecting rod 7 extends through a bore 50 in the pressure spindle 5.
  • the pressure controllable pump delivers liquid from a reservoir 11 into the pressure chamber 8 of the pitman housing 2. This liquid presses the sealing member 6 onto the sleeves 4 and thus brings about the rigidity of the pitman over its entire set length. On other hand, the liquid acts through the sealing member 6 and the sleeve 4 onto the pressure spindle 5 and thereby clamps the screw connection against the housing 2 of the pitman.
  • the mechanical force exerted by the ram through the connecting rod 7 and the sealing member 6 onto the liquid in the pressure chamber 8 is thus greater than the force which results from the liquid pressure multiplied by the cross section of the sealing member 6 so that the latter moves relative to the pitman housing 2 and is lifted off from the sleeve 4.
  • the hydraulic overload safety mechanism has a high response precision with a response point which is variable in a continuous manner in a definite range, the
  • a hydraulic overload safety device comprising a pitman adjustable in length for presses and similar machine tools, which includes: pitman housing means having a central blind bore opening in one direction and having its open end on the inside thereof provided with threads, sleeve means reciprocable in said bore, threaded spindle means threadedly engaging said threaded open end of said pitman housing means, and supporting said sleeve means, sealing means resting on said sleeve means, a connecting rod having one of its ends connected to said sealing means and being reciprocably guided by and in said sleeve means and in said threaded spindle means, the other end of said connecting rod being connectable to a ram, said sealing means together with the adjacent portion of said sleeve means and said pitman housing means defining a pressure chamber, pump means having a suction side, liquid storage means communicating with said suction side, said pump means also having a pressure side for communication with said pressure chamber to deliver liquid under pressure thereto and establish a pressure
  • a pitman according to claim 1 which includes means associated with said overload safety device and operable automatically in response to said overload safety device becoming effective to stop said press and in response to said overload safety device being in ineffective position to again place said press into operative position.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Press Drives And Press Lines (AREA)
  • Control Of Presses (AREA)
US392022A 1972-08-26 1973-08-27 Pitman adjustable in length for a press with hydraulic overload safety mechanism Expired - Lifetime US3892143A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2242067A DE2242067C3 (de) 1972-08-26 1972-08-26 Längenverstellbarer Pleuel für eine Presse mit hydraulischer Überlastsicherung

Publications (1)

Publication Number Publication Date
US3892143A true US3892143A (en) 1975-07-01

Family

ID=5854644

Family Applications (1)

Application Number Title Priority Date Filing Date
US392022A Expired - Lifetime US3892143A (en) 1972-08-26 1973-08-27 Pitman adjustable in length for a press with hydraulic overload safety mechanism

Country Status (5)

Country Link
US (1) US3892143A (de)
JP (1) JPS5633200B2 (de)
DE (1) DE2242067C3 (de)
GB (1) GB1426798A (de)
IT (1) IT993768B (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4096798A (en) * 1977-03-14 1978-06-27 Gulf & Western Manufacturing Company Press slide adjusting and overload protection assembly
US4166415A (en) * 1978-04-21 1979-09-04 Gulf & Western Manufacturing Company Press having overload responsive slide shut height adjusting mechanism
US4823687A (en) * 1986-12-04 1989-04-25 Kabushiki Kaisha Kosmek And Amada Company, Limited Die-height adjusting device of mechanical press
US4996743A (en) * 1990-01-29 1991-03-05 Formax, Inc. Mold plate drive linkage
US5345861A (en) * 1993-04-20 1994-09-13 The Minater Machine Company Press adjustment screw mechanism
US5349902A (en) * 1993-04-20 1994-09-27 The Minster Machine Company Press shutheight adjustment mechanism
US5682813A (en) * 1996-03-27 1997-11-04 The Minster Machine Company Press shutheight control through hydraulic pressure
AU693848B2 (en) * 1994-01-25 1998-07-09 Abb Ab Driving device for a bending unit
US20040003730A1 (en) * 2002-06-28 2004-01-08 Schuler Pressen Gmbh & Co. Kg Overload safety device in a press
CN104441756A (zh) * 2014-12-15 2015-03-25 济南二机床集团有限公司 一种压力机滑块连接器的调节螺杆套与导柱连接结构

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4026207A (en) * 1976-01-09 1977-05-31 The Continental Group, Inc. Pre-loaded ram-tool holder energy absorbing mechanism
US4235576A (en) * 1977-10-03 1980-11-25 Delta Materials Research Limited Presses
AT365494B (de) * 1980-05-05 1982-01-25 Gfm Fertigungstechnik Schnellaufende schmiedemaschine
US4677908A (en) * 1985-12-11 1987-07-07 Aida Engineering, Ltd. Slide adjusting device for a press
DE102007006539B4 (de) 2007-02-09 2013-02-21 Airbus Operations Gmbh Überlastsicherungsvorrichtung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2491279A (en) * 1947-06-25 1949-12-13 Dayton Rogers Mfg Co Safety overload pitman for power presses
US3190141A (en) * 1961-06-13 1965-06-22 Massey Schlatter A G Hydraulic overload safety device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1047626B (de) * 1953-07-18 1958-12-24 Schuler L Ag Presse mit Abschersicherung
DE1208580B (de) * 1961-06-13 1966-01-05 Massey Schlatter A G Hydraulische UEberlastsicherung

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2491279A (en) * 1947-06-25 1949-12-13 Dayton Rogers Mfg Co Safety overload pitman for power presses
US3190141A (en) * 1961-06-13 1965-06-22 Massey Schlatter A G Hydraulic overload safety device

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4096798A (en) * 1977-03-14 1978-06-27 Gulf & Western Manufacturing Company Press slide adjusting and overload protection assembly
DE2810595A1 (de) * 1977-03-14 1978-09-21 Gulf & Western Mfg Co Justier- und ueberlastungsschutz-vorrichtung fuer eine presse
US4166415A (en) * 1978-04-21 1979-09-04 Gulf & Western Manufacturing Company Press having overload responsive slide shut height adjusting mechanism
US4823687A (en) * 1986-12-04 1989-04-25 Kabushiki Kaisha Kosmek And Amada Company, Limited Die-height adjusting device of mechanical press
US4996743A (en) * 1990-01-29 1991-03-05 Formax, Inc. Mold plate drive linkage
US5345861A (en) * 1993-04-20 1994-09-13 The Minater Machine Company Press adjustment screw mechanism
US5349902A (en) * 1993-04-20 1994-09-27 The Minster Machine Company Press shutheight adjustment mechanism
AU693848B2 (en) * 1994-01-25 1998-07-09 Abb Ab Driving device for a bending unit
US5682813A (en) * 1996-03-27 1997-11-04 The Minster Machine Company Press shutheight control through hydraulic pressure
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
CN104441756A (zh) * 2014-12-15 2015-03-25 济南二机床集团有限公司 一种压力机滑块连接器的调节螺杆套与导柱连接结构

Also Published As

Publication number Publication date
DE2242067B2 (de) 1981-04-09
JPS4959367A (de) 1974-06-08
JPS5633200B2 (de) 1981-08-01
DE2242067C3 (de) 1981-11-19
DE2242067A1 (de) 1974-03-07
IT993768B (it) 1975-09-30
GB1426798A (en) 1976-03-03

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