US3771084A - Magnetic retrieval device - Google Patents

Magnetic retrieval device Download PDF

Info

Publication number
US3771084A
US3771084A US3771084DA US3771084A US 3771084 A US3771084 A US 3771084A US 3771084D A US3771084D A US 3771084DA US 3771084 A US3771084 A US 3771084A
Authority
US
United States
Prior art keywords
outer sleeve
sleeve
inner
outer
finger
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
Inventor
R Thon
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.)
Xerox Corp
Original Assignee
Xerox Corp
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 Xerox Corp filed Critical Xerox Corp
Priority to US28387272A priority Critical
Application granted granted Critical
Publication of US3771084A publication Critical patent/US3771084A/en
Anticipated expiration legal-status Critical
Application status is Expired - Lifetime legal-status Critical

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C1/00Magnetic separation
    • B03C1/02Magnetic separation acting directly on the substance being separated
    • B03C1/28Magnetic plugs and dipsticks
    • B03C1/284Magnetic plugs and dipsticks with associated cleaning means, e.g. retractable non-magnetic sleeve
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03GELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00Apparatus for electrographic processes using a charge pattern
    • G03G15/06Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0822Arrangements for preparing, mixing, supplying or dispensing developer

Abstract

A magnetic retrieval device including an outer sleeve of cylindrical configuration and an inner sleeve of cylindrical configuration, the inner sleeve being slidably mounted within the outer sleeve. The outer sleeve includes a first finger support mounted thereon and a slot contained therein and mounted just forward of the first finger support. A second finger support is mounted to the inner sleeve and is slidably adjustable within the slot of the outer sleeve. The inner sleeve includes a magnet mounted in the forward portion thereof, the inner sleeve and outer sleeve having relative movement by manipulation of the finger supports for placing the magnet between a first position attracting particles to the front face of the outer sleeve and a second position sufficiently distant from the front face such that the magnetic field of the magnet no longer attracts particles thereto. The outer sleeve may include a spoiler for preventing movement of particles along the sleeve upon movement of the inner sleeve.

Description

United States Patent [191 Thon Nov. 6, 1973 MAGNETIC RETRIEVAL DEVICE [75] Inventor: Robert H. Thou, Palmyra, N.Y

[73] Assignee: Xerox Corporation, Rochester, NY.

[22] Filed: Aug. 25, 1972 21 1 Appl. No.: 283,872

[52] US. Cl. 335/285, 294/65.5

Primary Examiner-George Harris Att0rney-Wil1iam Kaufman et al.

[5 7] ABSTRACT A magnetic retrieval device including an outer sleeve of cylindrical configuration and an inner sleeve of cylindrical configuration, the inner sleeve being slidably mounted within the outer sleeve. The outer sleeve in cludes a first finger support mounted thereon and a slot contained therein and mounted just forward of the first finger support. A second finger support is mounted to the inner sleeve and is slidably adjustable within the slot of the outer sleeve. The inner sleeve includes a magnet mounted in the forward portion thereof, the inner sleeve and outer sleeve having relative movement by manipulation of the finger supports for placing the magnet between a first position attracting particles to the front face of the outer sleeve and a second position sufficiently distant from the front face such that the magnetic field of the magnet no longer attracts particles thereto. The outer sleeve may include a spoiler for preventing movement of particles along the sleeve upon movement of the inner sleeve.

10 Claims, 3 Drawing Figures J2 1a Z2 MAGNETIC RETRIEVAL DEVICE This invention relates to magnetic retrieval devices and more particularly to a compact and highly manipulatable magnetic retrieval device for lifting particulate material.

There is, and always has been, a general need for a retrieval device capable of lifting magnetically attractable objects, devices or materials. In the art of electrostatographic imaging for example, the development system of the electrostatographic process can employ magnetic particulate material known as developer. In conventional form, development processes employ cascade distribution of developer over a surface area to be developed. Cascade distribution results in the spreading of particulate material, often in areas other than the developed surface, from which areas the material isdesirably retrievable. Prior art devices for retrievingsuch developer material employ brushes for cleaning the material out of the areas in which it has become disposed, or vacuum cleaning devices for removing the material. However, very often the material falls within crevices or small areas within the machine where a brush or vacuum device is unable to reach. In addition, brushes and vacuum devices result in permanent disposal of the developer material thus retrieved, thereby providing inefficiency and waste in operation.

Magnetic devices are desirably employed for retrieving metallic particles, and mechanical devices have been devised for grasping, lifting, etc. Such devices have, however, usually employed cumbersome mechanical contrivances such as plungers, and other similar forms of mechanical configurations. Plunger devices such as are typical in the prior art are inconvenient to manipulate with one hand, and most conventionally require two hands, and the high degree of manipulatability of a magnetic retrieval device such as is desired in accordance with the present invention cannot be realized by a retrieval device which requires two magnetic retrieval device including an outer sleeve. and

an inner sleeve slidably mounted within the outer sleeve. The outer sleeve includes a first finger support mounted thereon, while the inner sleeve includes a sec-. ond finger support mounted thereon. The inner and outer sleeves have relative motion as a result of the manipulation of said finger supports. A- magnetic device is mounted within the inner sleeve, the inner sleeve and the magnetic device being slidably movable within the outer sleeve between a first position causing an attraction of magnetically attractable materials to the outer sleeve and a second position reducing said attraction.

The foregoing objects and brief description as well as further features and advantages of the present invention will become more apparent from the following more detailed description and appended drawings wherein:

numeral 10, and as shown includes an outer sleeve 12- which is preferably cylindrical, and inner sleeve 14 which is also preferably cylindrical. It is understood, however, that other sleeve shapes can be easily employed. The outer sleeve 12 and inner'sleeve 14 are concentric, inner sleeve 14 being of slightly lesser diameter than the outer sleeve 12 and being adapted to ride along the common axis therein. The outer sleeve 12 includes a first finger support portion 16 whereas the inner sleeve 14 includes a second finger support portion 18. Mounted at one end of the inner sleeve 14 is a magnet 20. The magnet 20 may be any suitable type of magnetic device, such as a barium ferrite, or other types of high density ceramic permanent magnetic materials. The outer sleeve 12 also includes a molded spoiler 22 mounted close to the front fact 24 of the outer sleeve 12. The retriever 10 may be formed of any suitable nonmagnetic material such as any suitable thermoplastic or thermosetting moldable material. The finger supports 16 and 18 are each formed of a closed loop, as a complete encirclement such that pressure may be applied by insertion of fingers within the loops, along any interior face of the loop so as to manipulate sleeves 14 and 12 in the desired manner to facilitate the manipulation of the retriever as needed. The use of two fingers makes the device-l0 highly manipulatable for retrieval. An aperture in the form of a groove or slot 26 is provided in the outer sleeve 12 in a position whereby the finger support 18 may be slidably positioned along with the inner sleeve 14 within the interior of the outer sleeve 12.

In operation, when the retriever 10 is desired to be used, thefinger supports 16 and 18 are each spread apart so as to occupy a position such that the magnet 20 is positioned close to the front face 24 of the outer sleeve 12. The retriever is then placed in proximity with the magnetic material desired to be retrieved, such as the magnetic developer material employed in electrostatographic imaging, and the magnetic material will adhere to the front face 24 as a result of the magnetic attraction caused by the flux emananting from the magnet 20.

Upon retrieving the magnetic material as desired, the retriever 10 may be removed from the location wherein the magnetic material was retrieved and placed in an area wherein the magnetic material will be redeposited. Upon reaching the area where the magnetic material is to be deposited, the finger supports 16 and 18 are manipulated such that the inner sleeve 14 'is moved from the position wherein the magnet is close to the front face 24 to the second position wherein the inner sleeve 14 is moved closer to the rear face 28 of the outer sleeve 12. In this case, the magnet 20 now moves up the .sleeve 12 axially from the front face 24, thereby reducing the magnetic attraction at the front face 24, and causing the particles adhering to the front face 24 to fall therefrom. The spoiler 22, which is in the form of a lip or edge surrounding the outer perimeter of the outer sleeve 12 and which may be molded as part of the manufacture thereof or physically attached thereto as by gluing or like adhesive, but in either event integral therewith, acts to prevent magnetic particles from following the magnetic material up the outer side of the sleeve 12. When the magnet is moved to its rearward position, magnetic particles which travel along that portion of the outer sleeve 12 reach the spoiler 22 and are retained, thereby being prevented from moving further up the sleeve, until the magnetic attraction of the magnet 20 is such that the force is insufficient to hold the particles in position. At this point, the particles fall from the outer sleeve 12 into the area where it is desired to place the magnetic material. In this manner, magnetic material may be removed from one location and placed in another desired location. As stated hereinabove, this is particularly advantageous in an electrostatographic imaging device.

Because of the small size and extreme manipulatability provided by the use of corresponding finger holder 16 and 18, the device may be used to retrieve magnetic particles from difficult locations.

Referring to FIG. 2, a cross-sectional side view is illustrated of the device shown in FIG. 1, with the exception that a compression spring has been added. In the embodiment shown in FIG. 2, wherein like reference numerals refer to like components with reference to FIG. 1, a compression spring 30 has been added which corresponds to raised portions 32, formed on the interior of the back portion 28 of the outer sleeve 12, and 34 formed on the facing portion of the interior sleeve 14. The spring is compressed and places an expansion force maintaining the magnet in its first position abutting theinterior of the face portion 24 of the outer sleeve 12. Since the spring force provides a return force, it is only necessary that the finger grips illustrated in FIG. 2 as 36 and 38 are formed in semicircular portions. It would be obvious of course to form finger grips 36 and 38 as linear extensions from the outer and inner sleeves respectively since the only requirement in this embodiment is-that sufficient means he provided to place compressional force between the finger grips 36 and 38 in order to overcome the expansion force of the spring 30 which-is maintaining the magnet 20 against the inner portion of the face 24 of the outer sleeve 12.

Referring to FIG. 3, an alternative embodiment is illustrated wherein instead of a linear molded portion employed as the spoiler 22, a tampered section 40 is provided for reducing the attractive force of the magnetic field and preventing the particles from riding up the outside of the outer sleeve wall.

It would be apparent that the retrieval device of the present invention may be employed to retrieve other magnetically attractable materials as well as the particulate materials discussed in conjunction with the foregoing preferred embodiment. For example, large solid objects may be employed as retrieved objects in accordance with the strength of the magnet 20 and the width of the face 24.

Other variations and changes will be obviously apparent to those skilled in the art. It will be understood that the device shown in the embodiments'herein are done so for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from the scope and the spirit of the invention.

What is claimed is:

l. A magnetic retrieval apparatus comprising an outer sleeve, an inner sleeve enclosed by and slidably mounted within said outer sleeve, a first finger support mounted to said outer sleeve, a second finger support mounted to said inner sleeve, said second finger support extendable through said outer sleeve and aligned with said first finger support, said outer and inner sleeves having relative motion by manipulation of said finger supports, and magnetic means mounted within said inner sleeve, said inner sleeve and said magnetic means slidably moveable within said outer sleeve between a first position causing attraction of magnetically attractable materials to said outer sleeve and a second position reducing said attraction.

2. The apparatus of claim 1 wherein said outer sleeve includes a spoiler integral with said outer sleeve, said spoiler operative to inhibit the motion of magnetically attractable materials in accordance with the motion of said magnetic means between said first and said second position.

3. The apparatus of claim 1 wherein said first and second finger supports are formed as complete encirclements.

4. The apparatus of claim 1 further including a compression spring mounted between said inner and outer sleeves, said compression spring biasing said inner sleeve in said first position.

5. The apparatus of claim 4 wherein said finger supports are each formed by extension means derived from said inner and outer sleeves respectively, said finger supports adapted to have compressional force placed thereon for moving said inner sleeve against the compressional force of said spring.

6. A magnetic retrieval apparatus comprising an outer sleeve, said outer sleeve including a face portion, and a body portion, the body portion including a slot therein, an inner sleeve slidably mounted within said outer sleeve, a first finger support mounted to said outer sleeve, a second finger support mounted to said inner sleeve, said second finger support emerging through said outer sleeve through said slot, said inner sleeve axially movable within said outer sleeve by movement of said second finger support in said slot,

' said outer and inner sleeves having relative motion by manipulation of said finger supports, said inner sleeve and said magnetic means slidably movable within said outer sleeve between a first position causing attraction of magnetically attractable materials to said outer sleeve face portion and a second position reducing said attraction.

7. The apparatus of claim 6 wherein said outer sleeve includes a spoiler integral with said outer sleeve, said spoiler operative to inhibit the motion of magnetically attractable materials in accordance with the motion of said magnetic means between said first and said second position.

8. The apparatus of claim 6 wherein said first and second finger supports are formed as complete encirclements.

9. The apparatus of claim 6 further including a compression spring mounted between said inner and outer sleeves, said compression spring biasing said inner sleeve in said first position.

10. The apparatus of claim 9 wherein said finger supports are each formed by extension means derived from said inner and outer sleeves respectively, said finger supports adapted to have compressional force placed thereon for moving said inner sleeve against the expansion force of said spring.

Claims (10)

1. A magnetic retrieval apparatus comprising an outer sleeve, an inner sleeve enclosed by and slidably mounted within said outer sleeve, a first finger support mounted to said outer sleeve, a second finger support mounted to said inner sleeve, said second finger support extendable through said outer sleeve and aligned with said first finger support, said outer and inner sleeves having relative motion by manipulation of said finger supports, and magnetic means mounted within said inner sleeve, said inner sleeve and said magnetic means slidably moveable within said outer sleeve between a first position causing attraction of magnetically attractable materials to said outer sleeve and a second position reducing said attraction.
2. The apparatus of claim 1 wherein said outer sleeve includes a spoiler integral with said outer sleeve, said spoiler operative to inhibit the motion of magnetically attractable materials in accordance with the motion of said magnetic means between said first and said second position.
3. The apparatus of claim 1 wherein said first and second finger supports are formed as complete encirclements.
4. The apparatus of claim 1 further including a compression spring mounted between said inner and outer sleeves, said compression spring biasing said inner sleeve in said first position.
5. The apparatus of claim 4 wherein said finger supports are each formed by extension means derived from said inner and outer sleeves respectively, said finger supports adapted to have compressional force placed thereon for moving said inner sleeve against the compressional force of said spring.
6. A magnetic retrieval apparatus comprising an outer sleeve, said outer sleeve including a face portion, and a body portion, the body portion including a slot therein, an inner sleeve slidably mounted within said outer sleeve, a first finger support mounted to said outer sleeve, a second finger support mounted to said inner sleeve, said second finger support emerging through said outer sleeve through said slot, said inner sleeve axially movable within said outer sleeve by movement of said second finger support in said slot, said outer and inner sleeves having relative motion by manipulation of said finger supports, said inner sleeve and said magnetic means slidably movable within said outer sleeve between a first position causing attraction of magnetically attractable materials to said outer sleeve face portion and a second position reducing said attraction.
7. The apparatus of claim 6 wherein said outer sleeve includes a spoiler integral with said outer sleeve, said spoiler operative to inhibit the motion of magnetically attractable materials in accordance with the motion of said magnetic means between said first and said second position.
8. The apparatus of claim 6 wherein said first and second finger supports are formed as complete encirclements.
9. The apparatus of claim 6 further including a compression spring mounted between said inner and outer sleeves, said compression spring biasing said inner sleeve in said first position.
10. The apparatus of claim 9 wherein said finger supports are each formed by extension means derived from said inner and outer sleeves respectively, said finger supports adapted to have compressional force placed thereon for moving said inner sleeve against the expansion force of said spring.
US3771084D 1972-08-25 1972-08-25 Magnetic retrieval device Expired - Lifetime US3771084A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US28387272A true 1972-08-25 1972-08-25

Publications (1)

Publication Number Publication Date
US3771084A true US3771084A (en) 1973-11-06

Family

ID=23087930

Family Applications (1)

Application Number Title Priority Date Filing Date
US3771084D Expired - Lifetime US3771084A (en) 1972-08-25 1972-08-25 Magnetic retrieval device

Country Status (2)

Country Link
US (1) US3771084A (en)
NL (1) NL7311528A (en)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4620739A (en) * 1984-12-17 1986-11-04 William Coralline Bingo chip bell
US4813729A (en) * 1988-02-10 1989-03-21 Speckhart Frank H Magnetic retrieval tool
GB2232299A (en) * 1989-04-07 1990-12-05 Yoshitaka Aoyama Magnetic lifting apparatus
US5169193A (en) * 1991-12-09 1992-12-08 Stelmach John J Magnetic pickup tool
US5265887A (en) * 1991-12-09 1993-11-30 Stelmach John J Magnetic pickup tool
US5992911A (en) * 1998-01-20 1999-11-30 Honda Giken Kogyo Kabushiki Kaisha Magnet positioning apparatus for positioning a magnet into a subsurface region
US6533638B1 (en) * 2000-09-06 2003-03-18 Webb Nelson System and method for engaging a finger board
US6540577B1 (en) * 2000-09-11 2003-04-01 Webb Nelson Finger board assembly and amusement system
DE19951703C2 (en) * 1999-10-27 2003-07-31 Andreas Bellmann Switchable permanent magnet with moving magnetic piston
US20070132256A1 (en) * 2005-12-09 2007-06-14 Parris Earl H Magnetic tool cleaner
US20080083291A1 (en) * 2006-10-06 2008-04-10 Promega Corporation Apparatus and method for separating magnetic particles from a solution
US20080168811A1 (en) * 2007-01-11 2008-07-17 Invue Security Products Inc. Magnetic key for use with a security device
US20120230806A1 (en) * 2011-03-09 2012-09-13 Donald Rumpel Hearing aid battery handler
US20150020381A1 (en) * 2012-03-08 2015-01-22 Fourth Dimension Designs, Ltd. Magnetic Installation and Retrieval Tool for Fluid Lift Plungers
EP2727651A3 (en) * 2012-11-05 2017-04-26 Hamilton Sundstrand Corporation System and method for clearing chips from a magnetic chip collector

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2733949A (en) * 1956-02-07 russell
US2932538A (en) * 1959-04-07 1960-04-12 George Ronald Roux Magnetic retriever
US2970002A (en) * 1959-01-20 1961-01-31 Laviano Samuel Magnetic pickup
US2976075A (en) * 1959-07-17 1961-03-21 Monarch Tool & Machinery Co Magnetic pick-up device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2733949A (en) * 1956-02-07 russell
US2970002A (en) * 1959-01-20 1961-01-31 Laviano Samuel Magnetic pickup
US2932538A (en) * 1959-04-07 1960-04-12 George Ronald Roux Magnetic retriever
US2976075A (en) * 1959-07-17 1961-03-21 Monarch Tool & Machinery Co Magnetic pick-up device

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4620739A (en) * 1984-12-17 1986-11-04 William Coralline Bingo chip bell
US4813729A (en) * 1988-02-10 1989-03-21 Speckhart Frank H Magnetic retrieval tool
GB2232299A (en) * 1989-04-07 1990-12-05 Yoshitaka Aoyama Magnetic lifting apparatus
GB2232299B (en) * 1989-04-07 1993-11-03 Yoshitaka Aoyama Apparatus fir feeding apertured parts
US5169193A (en) * 1991-12-09 1992-12-08 Stelmach John J Magnetic pickup tool
US5265887A (en) * 1991-12-09 1993-11-30 Stelmach John J Magnetic pickup tool
US5992911A (en) * 1998-01-20 1999-11-30 Honda Giken Kogyo Kabushiki Kaisha Magnet positioning apparatus for positioning a magnet into a subsurface region
US6145902A (en) * 1998-01-20 2000-11-14 Honda Giken Kogyo Kabushiki Kaisha Magnet positioning apparatus for positioning a magnet into a subsurface region
DE19951703C2 (en) * 1999-10-27 2003-07-31 Andreas Bellmann Switchable permanent magnet with moving magnetic piston
US6533638B1 (en) * 2000-09-06 2003-03-18 Webb Nelson System and method for engaging a finger board
US6540577B1 (en) * 2000-09-11 2003-04-01 Webb Nelson Finger board assembly and amusement system
US20070132256A1 (en) * 2005-12-09 2007-06-14 Parris Earl H Magnetic tool cleaner
US7815234B2 (en) * 2005-12-09 2010-10-19 Parris Earl H Magnetic tool cleaner
US20100326468A1 (en) * 2005-12-09 2010-12-30 Parris Earl H Magnetic tool cleaner
US20080083291A1 (en) * 2006-10-06 2008-04-10 Promega Corporation Apparatus and method for separating magnetic particles from a solution
US20090272694A1 (en) * 2006-10-06 2009-11-05 Promega Corporation Apparatus and method for separation magnetic particles from a solution
US20080168811A1 (en) * 2007-01-11 2008-07-17 Invue Security Products Inc. Magnetic key for use with a security device
US20120230806A1 (en) * 2011-03-09 2012-09-13 Donald Rumpel Hearing aid battery handler
US20150020381A1 (en) * 2012-03-08 2015-01-22 Fourth Dimension Designs, Ltd. Magnetic Installation and Retrieval Tool for Fluid Lift Plungers
US9308608B2 (en) * 2012-03-08 2016-04-12 Fourth Dimension Designs, Ltd. Magnetic installation and retrieval tool for fluid lift plungers
EP2727651A3 (en) * 2012-11-05 2017-04-26 Hamilton Sundstrand Corporation System and method for clearing chips from a magnetic chip collector

Also Published As

Publication number Publication date
NL7311528A (en) 1973-11-26

Similar Documents

Publication Publication Date Title
US4117431A (en) Magnetic proximity device
GB954370A (en) Permanent magnet lifting device
US2417762A (en) Tool for magnetic lifting
CA1336612C (en) Magnetic lock closure device
GB1418222A (en) Magnetic actuator mechanism
GB1472845A (en) Magnetic actuator mechanism and electric pushbutton switch incorporating same
EP0879700A3 (en) Information processing apparatus
US3701557A (en) Adjustable magnetic door stop
DE2917232A1 (en) Permanent magnet indicator for piston in cylinder - has piston coated on sliding surfaces with permanent magnetic plastics material
EP1167109A3 (en) Selecting and switching apparatus
GB1412510A (en) Pushbutton mechanism
PT98798A (en) Device of actuation on the valve of discharge of an autoclism
US5404595A (en) Device for raising a toilet seat
US5265887A (en) Magnetic pickup tool
US2976075A (en) Magnetic pick-up device
US4274847A (en) Vacuum cleaner dust bag
EP0620573A3 (en) Flux spreading thin film magnetic devices.
DE69530960D1 (en) An electroconductive film forming material, a method of forming an electroconductive film using the same, and a method of manufacturing an electron emitting device, electron source and image forming apparatus
US4419644A (en) Switchable permanent magnetic holding device
JPH03173532A (en) Magnetic resonance imaging device
JPH0356736A (en) Dust shield for damper
US3693033A (en) Key operated pulse generating device
EP0232727B1 (en) Magnetic eraser dust collector
GB2020555A (en) Magnetic device for a lumbar belt
US5169193A (en) Magnetic pickup tool