US3915273A - Electromechanical safety lock - Google Patents

Electromechanical safety lock Download PDF

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Publication number
US3915273A
US3915273A US477998A US47799874A US3915273A US 3915273 A US3915273 A US 3915273A US 477998 A US477998 A US 477998A US 47799874 A US47799874 A US 47799874A US 3915273 A US3915273 A US 3915273A
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US
United States
Prior art keywords
bolt
locking rod
locking
sleeve
safety lock
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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
US477998A
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English (en)
Inventor
Bernhard Loschengruber
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.)
Condux Werk Herbert A Merges KG
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Condux Werk Herbert A Merges KG
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Filing date
Publication date
Application filed by Condux Werk Herbert A Merges KG filed Critical Condux Werk Herbert A Merges KG
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Publication of US3915273A publication Critical patent/US3915273A/en
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Expired - Lifetime legal-status Critical Current

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    • 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
    • F16P—SAFETY DEVICES IN GENERAL; SAFETY DEVICES FOR PRESSES
    • F16P3/00—Safety devices acting in conjunction with the control or operation of a machine; Control arrangements requiring the simultaneous use of two or more parts of the body
    • F16P3/08—Safety devices acting in conjunction with the control or operation of a machine; Control arrangements requiring the simultaneous use of two or more parts of the body in connection with the locking of doors, covers, guards, or like members giving access to moving machine parts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H27/00—Switches operated by a removable member, e.g. key, plug or plate; Switches operated by setting members according to a single predetermined combination out of several possible settings
    • H01H27/002—Switches operated by a removable member, e.g. key, plug or plate; Switches operated by setting members according to a single predetermined combination out of several possible settings wherein one single insertion movement of a key comprises an unlocking stroke and a switch actuating stroke, e.g. security switch for safety guards
    • H01H27/007—Switches operated by a removable member, e.g. key, plug or plate; Switches operated by setting members according to a single predetermined combination out of several possible settings wherein one single insertion movement of a key comprises an unlocking stroke and a switch actuating stroke, e.g. security switch for safety guards the switch being lockable by remote control, e.g. by electromagnet

Definitions

  • the safety lock for a housing accommodating a machine.
  • the safety lock has a locking bolt affixed to an openable housing door, a locking rod for blocking the bolt to lock the door and a mechanism which is actuatable by the locking bolt and which permits the machine (or its drive motor) to be energized only when the locking rod blocks the locking bolt.
  • the safety lock further has an electromagnet which, when energized, withdraws the locking rod from the locking bolt.
  • the safety lock further has a device which permits energization of the electromagnet only when the machine is at a standstill.
  • This invention relates to an electromechanical safety lock for a machine housing or a door to gain access to a machine which has moving (for example, rotating) components.
  • the safety lock is of the type which permits an opening of the door or housing component only after the drive motor of the machine has been switched off and the rotating components of the machine have come to a standstill.
  • Electromechanical safety locks of the above type are generally known and are disclosed, for example, in German Published Patent Applications (Auslegeschrift) Nos. 1,507,489 and 1,590,008. It is a common characteristic of both types of safety locks that a key is needed for their operation.
  • a handwheel-shaped housing portion which may be screwed on a threaded stub of the machine housing and, when so mounted, a locking can be effected by means of a cylinder lock which is provided with a key-operated catch.
  • the key In the locked position, the key may be withdrawn and the handwheel may rotate idly on the housing.
  • a force-transmitting connection must be established with the aid of the key between the cylinder lock and the handwheel to permit the latter to be wound off the threaded stub.
  • the door or housing portion to be opened is freed in this position; the key cannot be removed since the catch of the cylinder lock is in its work position.
  • the same key is used for operating a switch lock for turning on or off the drive motor of the machine. Since, when the handwheel is removed, the catch is in its operative position, the key cannot be used and thus the drive motor cannot be turned on. The key may be removed from the switch lock only when the latter is brought into its off position.
  • the thread pitch on the stub is so designed that the time needed for winding off the handwheel is always greater than the idling run of the rotating machine components.
  • the safety lock described in the German Published Pat. application No.. 1,590,008 relates to a safety switch for the starting and stopping of a machine drive motor wherein the key for opening the housing may be removed only after release by a timing (delay) mechanism.
  • the timing mechanism is wound up by turning on the motor switch and starts to run only after the motor switch is brought into its off position.
  • the safety lock has a locking bolt affixed to an openable housing door, a locking rod for blocking the bolt to lock the door and a mechanism which is actuatable by the locking bolt and which permits the machine (or its drive motor) to be energized only when the locking rod blocks the locking bolt.
  • the safety lock further has an electromagnet which, when energized, withdraws the locking rod from the locking bolt.
  • the safety lock further has a device which permits energization of the electromagnet only when the machine is at a standstill.
  • the particular advantage of the electromagnetic safety lock according to the invention resides in the fact that it may be mounted with simple means on the machine housing; the motor switch needs no modification. Also, since the electromagnetic safety lock according to the invention requires rio keys, the problem of lost keys or the use of unauthorized keys does not occur. Furthermore, a circumvention of the electromechanical safety lock is not possible since the latter is disposed in a closed casing.
  • FIG. 1 is a schematic view of a preferred embodiment of the invention in a machine open position.
  • FIG. 2 is a schematic view of the same embodiment in a machine locked position.
  • a housing door l-ID of a housing l-I accommodating a machine 18 (having rotary components) there is affixed a" locking bolt 1.
  • a bolt sleeve 2 which has an opening 2a and which is closed at its rear at 2b.
  • the bolt sleeve 2 and the locking bolt 1 have I coinciding longitudinal axes so that upon opening and closing of the housing door, the locking bolt 1 can slide into and out of the bolt sleeve 2.
  • the locking bolt 1 has a particular configuration, namely, it has a tapered free end la and, adjacent thereto, a notch-like detent 14.
  • a locking rod 3 having a terminus 3b which projects into the bolt sleeve 2 transversely to the bolt sleeve axis and which is adapted to be lockingly received by the notch 14 of the locking bolt 1.
  • the locking rod 3 is guided by a stationarily supported plate 16 which also serves as a spring seat for one end of a compression spring 3 a. The other end of the spring 3a engages a shoulder of the locking rod 3.
  • the tapered end portion 1a lifts the locking rod 3.
  • the notch 14 is disposed vertically below the free end 3b of the locking rod 3. The latter, biased downwardly by the compressed spring 3a, snaps into the notch 14, so that the locking process occurs in an impactlike manner.
  • a follower pin 4 which projects into the bolt sleeve 2 transversely to the bolt sleeve axis. Viewed from the bolt sleeve opening 2a, the follower pin is thus located behind the locking rod 3.
  • the follower pin 4 carries a compression spring 4a, one end of which is supported by a collar 17 of the follower pin 4.
  • the tapered portion la of the bolt 1 causes the follower pin 4 to be lifted.
  • the follower pin 4 rides on the upper edge of the locking bolt 1 as shown in FIG. 2. With the follower pin 4 the coil spring 4a is also lifted.
  • a blocking member such as a locking lever 12 is pivotally held at 8 and if formed of legs 12a and 12b.
  • the leg 12a may be swung into and out of a blocking position with respect to the leg 11b of the switch lever 11.
  • the leg 12b of the locking lever 12 is articulated to the locking rod 3, so that the movement of the latter causes a pivotal motion of the locking lever 12.
  • a circuit (not shown) is closed or opened for rendering the drive motor 19 energizable or non-energizable.
  • the switch pin 15 of the switch is spring-biased into the off position and is maintained there in the absence of a counter force exerted through the switch lever 11 by the stronger force of the spring 4a.
  • the drive motor 19 of the machine 18 can thus be turned on (energized) by actuating for example, manually a drive motor switch 20.
  • the drive motor 19 is turned off (de-energized) by the drive motor switch 20, the drive motor l9-emits a signal which is applied to a timing relay 21.
  • the timing relay 21 Upon termination of the delay period of the relay 21, the latter closes its contacts, which occurrence sets an electromagnet 5 into an energizable state.
  • the electromagnet 5 When the electromagnet 5 is in such an energizable state, it may be energized (that is, connected to a current source) or deenergized by a switch 22 which may be manually operated.
  • the electromagnet 5 is energized by actuating the switch 22, it attracts an armature 6.
  • an armature lever 13, connecting the armature 6 with the locking rod 3 executes a counterclockwise pivotal motion about its pivot 7 and thus the force exerted by the electromagnet 5 is transmitted by the armature lever 13 to the locking rod 3.
  • the latter overcoming the force of the spring 3a, is lifted to such an extent that its lower terminus 3b clears the notch 14 so that the locking bolt 1 may now be withdrawn from the locking sleeve 2 for the purpose of opening the machine housing.
  • the delay period of the relay 21 is adjustable and is expediently selected such that it is longer than the period of idling machine rotation as the drive motor of the machine is de-energized. It is thus apparent'that the timing relay may be set for different idling periods and thus is adapted for use in different types of machines.
  • the entire electromagnetic safety lock has small spatial requirements and is disposed in a casing (not shown) which has a relatively rigid rear wall (also not shown) for receiving, fixedly or pivotally, the abovedescribed components of the lock.
  • the bolt sleeve 2, too, is affixed to this casing wall.
  • the locking rod 3 projects with its free end 3b into the bolt sleeve 2 to a greater extent than the follower pin 4 when the machine housing H is open (see FIG. 1) and since the follower pin 4 is disposed closely behind the locking rod 3 as viewed from the opening 2a, it is impossible to exert, by means of a screw driver or similar tool, a pressure on the follower pin 4 for the purpose of actuating the switch 10 without first lifting the locking rod 3. Should this occur, however, the locking lever 12 would rotate clockwise and thus, with its leg 12a, would block the leg 11b of the switching lever 1 1.
  • the electromechanical safety lock can be operated only by means of the locking bolt 1.
  • the latter is affixed to an openable part (the door HD) of the machine housing H so that a manipulation of the electromechanical safety lock which would lead to an energization of the drive motor in an open position of the ma chine housing is not possible.
  • An electromechanical safety lock for a housing door of a housing accommodating a machine that includes a drive motor comprising in combination:
  • a bolt sleeve affixed to said housing and having means defining a sleeve opening at one end of the bolt sleeve;
  • a locking rod having a free terminus projecting transversely into said sleeve, said locking rod having a first position in which said free terminus has an advanced position in said bolt sleeve, saidlocking rod having a second position in which said free terminus has, a withdrawn position in said bolt sleeve;
  • first switch means for setting said drive motor into an energizable state and into a non-energizable state
  • first coupling means for connecting said follower pin to said first switch means for setting said drive motor into said non-energizable state when said follower pin is moved into its said first position and for setting said drive motor into said energizable state when said follower pin is moved into its said second position;
  • a locking bolt affixed to said housing door for movement therewith, said locking bolt being oriented for introduction into and withdrawal from said bolt sleeve through said sleeve opening, said locking bolt including means for moving said locking rod and said follower pin from their respective first position into their respective second position as said locking bolt moves inwardly within said bolt sleeve, said locking bolt further including detent means for receiving said free terminus of said locking rod when said locking bolt is in a fully introduced position in said bolt sleeve for blocking said locking bolt in said bolt sleeve; said locking rod moving into its said first position when said free terminus is received by said detent means;
  • j. means responsive to the operational condition of said machine for setting said electromagnet into the energizable state only when said machine is at a standstill.
  • said means responsive to the operational condition of said machine includes an adjustable timing relay connected to the drive motor for receiving a signal from the drive motor upon deenergization of the latter; said timing relay being connected at least indirectly to said electromagnet for setting the electromagnet into said energizable state after a dealy period running from the moment of de-energization of the drive motor.
  • said first coupling means includes a lever operatively connected to said first switch means for opening or closing said first switch means and a spring constituting the sole connection between said follower pin and said lever.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Computer Security & Cryptography (AREA)
  • Auxiliary Devices For Machine Tools (AREA)
  • Lock And Its Accessories (AREA)
  • Power-Operated Mechanisms For Wings (AREA)
US477998A 1973-06-13 1974-06-10 Electromechanical safety lock Expired - Lifetime US3915273A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2329964A DE2329964C3 (de) 1973-06-13 1973-06-13 Elektromechanische Sicherheitsverriegelung seinrichtung

Publications (1)

Publication Number Publication Date
US3915273A true US3915273A (en) 1975-10-28

Family

ID=5883812

Family Applications (1)

Application Number Title Priority Date Filing Date
US477998A Expired - Lifetime US3915273A (en) 1973-06-13 1974-06-10 Electromechanical safety lock

Country Status (6)

Country Link
US (1) US3915273A (enrdf_load_stackoverflow)
AT (1) AT338366B (enrdf_load_stackoverflow)
CH (1) CH577141A5 (enrdf_load_stackoverflow)
DE (1) DE2329964C3 (enrdf_load_stackoverflow)
FR (1) FR2233558B3 (enrdf_load_stackoverflow)
GB (1) GB1478028A (enrdf_load_stackoverflow)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012063A (en) * 1975-11-26 1977-03-15 Ametek, Inc. Interlock latch assembly for centrifugals
US4379481A (en) * 1977-12-27 1983-04-12 North American Philips Corporation X-Ray apparatus and closure mechanism therefor
US5131515A (en) * 1991-04-19 1992-07-21 Westlake Farms, Inc. Safety apparatus closure lock controlling access to rotational member
USRE34396E (en) * 1984-08-16 1993-10-05 Helmut Letzel Safety interlock switching device for protecting equipment
WO1995023269A1 (en) * 1994-02-25 1995-08-31 Trimec Securities Pty. Limited Electromagnetic lock
US5605429A (en) * 1993-06-30 1997-02-25 Eastman Kodak Company Door safety system for storage phosphor cassette autoloader
AU676629B2 (en) * 1994-02-25 1997-03-13 Assa Abloy Australia Pty Limited Improvements in electromechanical locks
US6560495B1 (en) * 1998-06-29 2003-05-06 Shin Caterpillar Mitsubishi Ltd. Method and device for locking work machine
US20080078658A1 (en) * 2006-09-29 2008-04-03 Eja Limited Safety switch
EP1906421A3 (en) * 2006-09-29 2009-01-07 Eja Limited Safety Switch
CN101911235A (zh) * 2008-01-29 2010-12-08 西门子公司 用于强制打开触头元件且具有保持关闭功能的安全开关以及将具有锁定功能的安全开关的触头元件强制打开的方法
US20110185778A1 (en) * 2010-02-04 2011-08-04 Satoshi Miyamoto Machine tool
US20120222945A1 (en) * 2011-03-02 2012-09-06 Siemens Aktiengesellschaft Electrical Switch
CN103640046A (zh) * 2013-12-17 2014-03-19 上海贞元实业有限公司 锁刀电路及锁刀装置
CN103971997A (zh) * 2013-02-01 2014-08-06 通用电气公司 用于断路器的电力操作器及其方法

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1513823A (en) * 1975-03-12 1978-06-14 Unimax Switch Ltd Safety device for guarded machinery
NL182609C (nl) * 1977-02-10 1988-04-05 Philips Nv Videoplatenspeler.
DE3242525A1 (de) * 1982-11-18 1984-05-24 Rheinmetall GmbH, 4000 Düsseldorf Sicherheitstuerverriegelung
EP0171453B1 (de) * 1984-08-16 1989-01-11 Letzel, Helmut Vorrichtung zur Sicherheitsverriegelung bei Schutzeinrichtungen zum Verhindern des Eingriffs in gefahrbringende Räume
DE3444325A1 (de) * 1984-12-05 1986-06-12 Rheinmetall GmbH, 4000 Düsseldorf Verriegelungs- und sicherheitsvorrichtung und verfahren zu ihrem betrieb
FR2646074A1 (fr) * 1989-04-24 1990-10-26 Ronic Ind Dispositif de securite electrique commande par couvercle de cuve dans un appareil de preparation culinaire
DE4015797A1 (de) * 1989-05-17 1990-12-06 Letzel Helmut Vorrichtung zur sicherheitsverriegelung bei schutzeinrichtungen

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1837244A (en) * 1925-12-07 1931-12-22 Thomas S Watson Safety control for extractor covers and the like
US2738072A (en) * 1952-09-04 1956-03-13 Gen Electric Time controlled cover lock for clothes washers and the like
US3161273A (en) * 1963-05-07 1964-12-15 Krantz Aachen H Electronic monitor device for centrifuges
US3734290A (en) * 1971-10-20 1973-05-22 Maytag Co Latch mechanism
US3762552A (en) * 1971-10-20 1973-10-02 Maytag Co Motion sensing latch system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1837244A (en) * 1925-12-07 1931-12-22 Thomas S Watson Safety control for extractor covers and the like
US2738072A (en) * 1952-09-04 1956-03-13 Gen Electric Time controlled cover lock for clothes washers and the like
US3161273A (en) * 1963-05-07 1964-12-15 Krantz Aachen H Electronic monitor device for centrifuges
US3734290A (en) * 1971-10-20 1973-05-22 Maytag Co Latch mechanism
US3762552A (en) * 1971-10-20 1973-10-02 Maytag Co Motion sensing latch system

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012063A (en) * 1975-11-26 1977-03-15 Ametek, Inc. Interlock latch assembly for centrifugals
US4379481A (en) * 1977-12-27 1983-04-12 North American Philips Corporation X-Ray apparatus and closure mechanism therefor
USRE34396E (en) * 1984-08-16 1993-10-05 Helmut Letzel Safety interlock switching device for protecting equipment
US5131515A (en) * 1991-04-19 1992-07-21 Westlake Farms, Inc. Safety apparatus closure lock controlling access to rotational member
US5605429A (en) * 1993-06-30 1997-02-25 Eastman Kodak Company Door safety system for storage phosphor cassette autoloader
GB2293204A (en) * 1994-02-25 1996-03-20 Trimec Securities Pty Ltd Electromagnetic lock
AU676629B2 (en) * 1994-02-25 1997-03-13 Assa Abloy Australia Pty Limited Improvements in electromechanical locks
GB2293204B (en) * 1994-02-25 1997-07-09 Trimec Securities Pty Ltd Electromagnetic lock
WO1995023269A1 (en) * 1994-02-25 1995-08-31 Trimec Securities Pty. Limited Electromagnetic lock
US6560495B1 (en) * 1998-06-29 2003-05-06 Shin Caterpillar Mitsubishi Ltd. Method and device for locking work machine
US7928330B2 (en) 2006-09-29 2011-04-19 Rockwell Automation Limited Safety switch
US20080078658A1 (en) * 2006-09-29 2008-04-03 Eja Limited Safety switch
EP1906421A3 (en) * 2006-09-29 2009-01-07 Eja Limited Safety Switch
CN101911235A (zh) * 2008-01-29 2010-12-08 西门子公司 用于强制打开触头元件且具有保持关闭功能的安全开关以及将具有锁定功能的安全开关的触头元件强制打开的方法
US20100307899A1 (en) * 2008-01-29 2010-12-09 Werner Puri Safety switch having a hold-closed function for positive opening of contact elements; and method for positive opening of contact elements of a safety switch with a locking function
US8969746B2 (en) 2008-01-29 2015-03-03 Siemens Aktiengesellschaft Safety switch having a hold-closed function for positive opening of contact elements; and method for positive opening of contact elements of a safety switch with a locking function
CN101911235B (zh) * 2008-01-29 2015-04-01 西门子公司 用于强制打开触头元件且具有保持关闭功能的安全开关以及将具有锁定功能的安全开关的触头元件强制打开的方法
US20110185778A1 (en) * 2010-02-04 2011-08-04 Satoshi Miyamoto Machine tool
US9041258B2 (en) * 2010-02-04 2015-05-26 Dmg Mori Seiki Co., Ltd. Machine tool
US20120222945A1 (en) * 2011-03-02 2012-09-06 Siemens Aktiengesellschaft Electrical Switch
US8610522B2 (en) * 2011-03-02 2013-12-17 Siemens Aktiengesellschaft Electrical switch
CN103971997A (zh) * 2013-02-01 2014-08-06 通用电气公司 用于断路器的电力操作器及其方法
US20140218139A1 (en) * 2013-02-01 2014-08-07 General Electric Company Electrical operator for circuit breaker and method thereof
US9184014B2 (en) * 2013-02-01 2015-11-10 General Electric Company Electrical operator for circuit breaker and method thereof
CN103971997B (zh) * 2013-02-01 2018-03-30 通用电气公司 用于断路器的电力操作器及其方法
CN103640046A (zh) * 2013-12-17 2014-03-19 上海贞元实业有限公司 锁刀电路及锁刀装置

Also Published As

Publication number Publication date
DE2329964A1 (de) 1975-01-09
DE2329964C3 (de) 1975-12-11
ATA360374A (de) 1976-12-15
DE2329964B2 (de) 1975-05-07
FR2233558B3 (enrdf_load_stackoverflow) 1977-04-08
GB1478028A (en) 1977-06-29
CH577141A5 (enrdf_load_stackoverflow) 1976-06-30
AT338366B (de) 1977-08-25
FR2233558A1 (enrdf_load_stackoverflow) 1975-01-10

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