FR2489283A1 - MAGNET FOR LIFTING LOADS - Google Patents

Abstract

A. LOAD LIFTING MAGNET WITH SEVERAL MAGNETIC COILS 6, 7, 8, ARRANGED BELOW A MAGNETIC CYLINDER 1 BETWEEN EXTERNAL POLES 2, COAXIALLY AROUND A VERTICAL CENTRAL POLE 3, 4, 5 AND SURFACES OF BASE OF DIFFERENT SIZE. B. CHARACTERIZED IN THAT THE LARGER DIAMETER MAGNETIC COIL 8 IS ARRANGED ABOVE THE SMALLER DIAMETER 6 MAGNETIC COIL. C. MAGNET APPLICABLE TO LIFTING AND TRANSPORTING LOADS.

Description

The invention relates to a load lifting magnet with a plurality of

  magnetic coils having a different base surface, disposed below a magnet yoke between outer faces, coaxially around a vertical central pole. A loading magnet of this kind following the

  DE 474 244 discloses a plurality of magnetic coils con-

  centric in a plane, including the winding direction and polarity

  are identical. The base plate and the pin rings separating the coils from each other consist of

  in a cast material. In these magnets

  the iron base plate encloses part of the lines of force over a short length, and suspends their effect, in particular

  for the outermost coil, towards the outside.

  The magnetic flux is directly short-circuited by

  In this area, no force or only a reduced force is applied to the object to be carried.

  It is also for a lifting magnet

  charging device according to DE 240 450 having a large DC-excited main coil and an internal auxiliary coil energized with alternating current. The lines of force do not reach, at the edge of the load to be lifted,

  only a shallow depth of penetration. This lifting magnet

  also has the disadvantage that, in

  its use of direct current and alternating current

  tif, it is necessary to provide two cables of supply to the magnet. The above mentioned load lifting magnets have a circular base surface and are therefore not suitable for lifting loads in the corners of rooms, containers or wagons. DE 240 450 also mentions a load lifting magnet with a rectangular base surface, which presents the same

  disadvantages than those spaced above.

  The object of the present invention is to provide a load-lifting magnet in which is obtained a

  great penetration depth over the entire base area.

  For this purpose, the magnet is characterized in that the larger magnetic coil is disposed above

  the smallest magnetic coil.

  Each magnetic coil is adapted with its central pole to produce an even distribution of

  the induction on the whole of the magnet. Thanks to the great

  Between the outer pole and the central leptle, the dispersion in the coil dengtre is reduced and the depth of penetration of the magnetic field into an object to be lifted is increased. Free space below the largest coil

  magnet and near the smaller coil

  cooling of magnetic coils by circulation

natural air.

  According to another embodiment of the invention

  three magnetic coils of different size,

  partially overlap, are arranged one above the other.

  The load-lifting magnet preferably forms a rectangle on the opposite longitudinal sides of which the outer faces of the magnet are arranged. The front plates of the load lifting magnet may furthermore be provided with ventilation holes which have, on their side

  inside, oblique coverings open upward.

  This load-lifting magnet has a uniform distribution of induction throughout its length, and it allows load taking even in the corners of containers or the like. The magnetic circuit is closed exclusively by the product to be transported. In the case of load-bearing magnets according to the invention, provided with several magnetic coils placed in different planes, with decreasing coil widths in the direction of the polar mass, a decrease of the induction in the direction of the polar mass is prevented. front faces of the magnet. The highest resistance to dispersion

  from reel to reel that we get, also increases the pro-

  melter penetrating the magnetic field to the frontier faces

  of the magnet which are not exceeded by the coils.

  The ventilation orifices do not influence the magnetic flux adversely and give the possibility of a natural circulation of the air, so that the heating of the load-bearing magnet is reduced or that, for the same

  warm up, the power can still be increased.

  The following description refers to an example

  embodiment with reference to the accompanying drawings in the

  which: - Figure 1 is an elevational view through the

  bottom of a charge carrying magnet according to the invention.

  FIG. 2 is a sectional view through II-II

of Figure 1.

  FIG. 3 is a sectional view through III-III

of Figure 1.

  The magnetic yoke covers the entire base surface of the load-bearing magnet. It is present on these longest sides, two outer faces 2, and, at

  front ends, front plates 9 with four ori-

  ventilation units 11 each provided with an integral covering

  oblique 12. Below the magnetic yoke 1 are

  arranged, between the outer faces 2, three magnetic coils

  6, 7, 8 of a different size around the central

  third, fourth and fifth, so that the superimposed

partially overlap.

  The magnetic flux is directed, from the outer edges 2, through the body to be lifted, which, in

  this case, is a round object indicated by lines in

  points in Figure 2, towards the lower center pole 5. Since this is, in the case shown, a long object, a second load lifting magnet, among several attached to a cross, is indicated by a dot-dash line at a distance from the first magnet shown in detail

  The magnetic coils 6, 7 and 8 are protected

  downwards against damage by a plate

of manganese steel 10.

-489283

R E V E N D I C A T I 0 N S

  1) Charging lifting magnet with several

  two magnetic coils (6, 7, 8) arranged below one

  magnetic yoke (1) between outer faces (2), coaxially

  a vertical central pole (3, 4, 5) and base surfaces of different sizes, characterized in that the larger-diameter magnetic coil (8) is arranged

  above the magnetic coil (6) of smaller diameter.

  2) Magnet according to claim 1, characterized

  in that it comprises three magnetic coils (6, 7, 8)

  superimposed of different size.

  3) Magnet according to one of claims 1

  or 2, characterized in that the magnetic coils (6, 7, 8)

overlap in part.

  4) Magnet according to any one of the

  1 to 3, characterized in that it has, seen in plan, a rectangular shape, on the longest sides of

  which are arranged the outer p81es (2).

   Magnet according to Claim 4, characterized in that on the front sides of the magnet, front plates are arranged between the outer faces (9).

  provided with ventilation openings (11).

  6) Magnet according to claim 5, characterized

  in that the ventilation holes (11) are provided on

  the inner face of the front plates (9) with coverings

oblique elements (12).

-ssh l