US 3159418 A
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Description (OCR text may contain errors)
' Dec. 1, 1964 J. J. HANSEN ELECTROMAGNETIC ANDVACUUMLIFTER Filed Feb. 20, 1963 I ENTOR. Jonas (JEA/JE/V i /WEN United States Patent 3,159,418 ELECTROMAGNETIC AND VACUUM LIFTER Jrgen Jensen Hansen, Fredensvej 39, Charlottenlund, Denmark Filed Feb. 20, 1963, Ser. No. 259,908 Claims priority, applicatgr/iggenmark, Mar. 1, 1962,
3 Claims. (Cl. 294-64) The present invention relates to a lifting unit for lifting magnetizable as well as non-magnetizable materials.
It is known to use an electromagnet for the lifting of magnetizable material and to use a suction cup for the lifting of non-magnetizable materials. But if such materials are to be lifted alternately, it requires a comparatively long time and much labor to change the unit from one form of lifting means to the other.
The object of the present invention is to provide a1ifting unitin which an electromagnet is combined with an annular suction cap, the latter being arranged closely around the electromagnet and mounted thereon for axial sliding movement, so that it may be displaced backward of the electromagnet when the latter is to be used, or displaced in front of the electromagnet, when the suction cup is to be used.
Another object of the invention is to arrange the combined electromagnet and suction cup in such a manner that the intermittent axial displacement of the suction cup may be accomplished by pneumatic means. Such a fluid pressure actuation may be accomplished by providing an annular chamber between the opposed sliding faces of the electromagnet and the suction cup, by providing a passage or passages in the unit in communication with the chamber and to which may be supplied alternately pressure or vacuum for the displacement of the suction cup on the electromagnet, and by providing between the suction cup and the electromagnet suitable annular seals to confine the positive and negative pressures, and also to exclude foreign matter from the sliding faces of the two relatively movable parts of the unit.
In a lifting unit of the kind referred to, the machine to be used for alternatingly producing vacuum and pneumatic pressure for the operation of the suction cup in picking up and releasing a non-magnetizable article, may also be used to cause the slidable displacement of the suction cup on the electromagnet. This use of a vacuum or pneumatic pressure is advantageous and it permits either the magnet or the suction cup to be quickly brought into operative position.
The accompanying drawing shows a central vertical sectional view through a lifting unit embodying the invention.
An electromagnet 1 having a magnet coil 2 is by means of a suspension member 3 suspended in a hoisting apparatus having the lifting members 4, 5 and 6. The magnet hangs on a ball surface 3a on the suspension member 3 which latter is disposed in a central opening 7 in the magnet 1. The opening 7 has a diameter so much larger than the diameter of the suspension member 3 that the magnet can freely adjust itself somewhat obliquely in all directions relative to the suspension member 3, so that the bottom face or carrying surface of the magnet is able to adjust itself parallel to the article to be lifted. The suction cup which surrounds the magnet 1 has a resilient annular portion 8, of India rubber or a similar yielding material. The annularly shaped portion Sis clamped in between an annular portion 9 and an annular portion 10 slidably arranged on the magnet 1. The vacuum chamber not the suction cup communicates through a filter 12, a passage 13 and a movable pipe 14 with a vaccum pump 3,159,418 Patented Dec. 1, 1964 "ice and pressure pump not shown. Between the annular portion 10 and the magnet 1 is formed an annular chamber 15 the smallest height of which is limited by means of a stop pin or stud 16. The chamber 15 communicates through passages 17 and 18 and a flexible pipe 19 with said vacuum and pressure pump by means of suitable changeover valves of known kind. When a vacuum is established in the chamber 15, the suction cup consisting of parts 8, 9, 10 is kept in the position shown in full line, the operative position of the suction cup.
When pneumatic pressure is established in the chamber 15, the suction cup is moved up and held in the position shown in dotted lines so that the magnet may be used for lifting. Between the outer cylindrical surface of the upright body of the electromagnet 1 and the inner face of the rigid body portion 10 of the suction cup, are tightly fitting sealing rings 24 to effectively seal the chamber 15 from the space outside of the same and prevent the loss of either positive or negative pressures in that chamber. In order to protect the sliding surfaces of the electromagnet and the suction cup, from grit or other foreign matter, there is provided at the lower portion of the unit an annular flexible elastic sealing member 21 clamped between the lower portions of the electromagnet and the body 10, and at the upper portion of the unit there is an annular flexible sealing member 22 clamped between the upper portions of the electromagnet and the part 10. In order to protect the suction cup against damaging blows when the unit is in use, a protective annular shield 23 may be carried by the top of the electromagnet and disposed around the suction cup in spaced relation thereto.
It will be noted that the opposed slidably engaged faces of the electromagnet and suction cup have a stepped formation to provide the chamber 15 so that opposed portions of the two relatively movable parts of the unit will be relatively moved by either positive or negative pressures in the chamber, and thus the suction cup will be moved upwardly when pneumatic pressure is created in the chamber 15 and be moved downwardly into engagement with the stop 16 when a vacuum is created in the chamber.
I declare that what I claim is:
1. In a lifting unit for lifting either magnetizable material or non-magnetizable material, the combination of an upright electromagnet having a bottom face to engage magnetizable' material, an annular suction cup having a rigid body surrounding said electromagnet, said body of the cup having a resilient lower end to engage non-magnetizable material, means mounting the body of said suction cup on said electromagnet for axial sliding movement to dispose said lower end of the suction cup either above or below the plane of the bottom face of the electromagnet, and means for the intermittent displacement of the suction cup on the electromagnet for alternately using the electromagnet or the suction cup, said means forthe displacement of said suction cup being fluid pressure-operated and includes an annular chamber between opposed portions of said suction cup body and said electromagnet body, a fluid passage in said electromagnet and in communication with said chamber, and means to supply a positive or a negative fluid pressure to said passage to cause the intermittent displacement of the suction cup on the electromagnet.
2. A lifting unit according to claim 1 in which said suction cup and said electromagnet have opposed slidable bearing surfaces both above and below the said opposed portions which form said annular chamber, together with tightly fitting sealing rings between said opposed bearing surfaces of the suction cup and the electromagnet.
3. A lifting unit according to claim 2 in which said 3 4 body of the suction cup is of less height than said body References Cited by the Examiner of the electromagnet, together with means for excluding UNITED STATES PATENTS fore1gn matter from the shdably engaged bearing faces of the suction cup and the electromagnet, the last mentioned 1181112 5/16 chaflebols X means comprising an upper flexible annular member be- 5 1,298,559 8/26 Cohen 29465'5 X tween the upper portions of the suction'cup and the elec- 4/31 Hayes 294' 64 tromagnet and a-lowerflexible annular member between the lower portions of the suction cup and the electro- JOHN BURNS Pnmary Examiner magnet. JOHN P. WILDMAN, Examiner.