GB2212330A - Demagnetising apparatus - Google Patents

Description

11 2212330 "Improvements in and relating to apparatus for demagnetising"

The invention relates to apparatus for demagnet-ising objects, especially annular components.

For the purpose of demagnetising components, for example ball bearings, gear rings, piston rings, tube springs and workpieces, demagnetising coils are arranged in a frame around a demagnetising zone, which coils produce in the demagnetising zone an alternating field through which the components that are to be demagnetised are passed. In accordance with German Patent Application DE-OS 36 25 621 the demagnetising coils can be fed with phase-displaced alternating currents in order to produce a rotary field. The demagnetising zone can be surrounded by a plurality of M demagnetising coils or in a rectangular shape in the form of a ring. The rotation frequency of the rotary field can be produced by means of a controllable generator by means of an adjustable wobble frequency.

The components that are are to be passed through the demagnetising zone should be arranged as nearly co-axially as possible with the axis in the conveying direction that passes through the centre point of the demagnetising zone, in order for the demagnetisation to be as uniform as possible. Since the components that are to be demagnetised can be of various dimensions or diameters, in conventional demagnetising devices time- c i consuming alignment of the components is required each time.

It is possible to construct a demagnetising apparatus according to the invention in which components having different dimensions or diameters can in simple manner be conveyed through the centre of the demagnetising zone.

The invention provides demagnetising apparatus having demagnetising coils, arranged around a demagnetising zone, which are fed by a demagnetising generator to produce a rotary field, and parallel guide members that extend through the demagnetising zone symmetrically with respect to a central axis extending through a centre point of the demagnetising zone and are adjustable centrically in the same sense.

Annular or rod-like components, especially, can be pushed between the guide members, the radial distance.from the guide members to the centre point then being set according to the radius of the components. It is thus possible to convey even ready-packed ball bearings, gear rings, piston rings, tube springs, and the like through the demagnetising chamber co-axially therewith.

The components may be conveyed one after the other n a row by means of a forward feed, which may be in the form of a chain feed or a lifting cylinder. The elements of the feed that enter the demagnetising zone, and the guide members, are then preferably 1 1 made from non-magnetic material, for example, special steel, in order not to disturb the demagnetising f ield.

The guide members are preferably in the form of special steel tubes which rest in contact with the exteriors of the components, the components being located between the guide members. By way of a handwheel or an adjusting member driven by a motor, all the guide members together can be be moved away from and towards the centre point of the demagnetising zone. The handwheel or other adjusting member may then act, by way of shafts and gears arranged outside the demagnetising zone, on connecting rods, aligned radially towards the central axis, to which the guide members are secured. The connecting rods are preferably actuated by means of threaded rods that are rotatable by way of bevel gears and by way of drive shafts connected to the bevel gears. Instead of a mechanical coupling by way of gearwheels, however, it would also be possible to use linear motors which are coupled mechanically and/or electrically in such a manner that the requisite concentric adjustment of the guide members in the same sense is still possible.

For demagnetising components that are not circular, but have a nonsymmetrical outer shape, it is also possible for the guide members to be made adjustable to suit the asymmetric shape of the components.

It is especially advantageous so to design the guide members on the feed side that the lower guide members project beyond the ends of the upper guide members, as a result of which the components that are to be demagnetised can be placed on the lower guide members from above without difficulty.

one form of demagnetising apparatus constructed in accordance with the invention will now be described by way of example only with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of an apparatus for demgnetising components; Figure 2 is a schematic end elevation view of an adjusting device of the apparatus shown in Figure 1.

Referring to the drawings, and initially to Figure 1, one form of demagnetising apparatus according to the invention comprises a frame 1, a demagnetising frame 2, guide members indicated generally by the reference numeral 3, and a conveyor device 4. Arranged in the demagnetising frame are magnetic coils 5 to 8 which are fed by a rotary- field generator (not shown) to produce a rotary field. Surrounded by the magnetic coils 5 to 8 is a demagnetising zone 9 through which four tubes 10 to 13 of non-magnetic special steel, serving as the guide members 3, extend parallel to one another. The special steel tubes 10 to 13 are adjustable in the same sense concentrically with respect to the central axis 15 by a handwheel 14 by way of an adjusting device 16.

1 tr 1 4 1 1 The conveyor device 4 has a non-magnetic carrier member 17 which can be moved through the demagnetising zone 9 in the conveying direction, the direction of the arrow b, by a chain drive 18. The conveyor device 4 may be driven by a controllable direct-current motor (not shown) or the like.

The special steel tubes 10 to 13 are so arranged in the feed region, indicated generally by the reference number 19, that the lower tubes 12 and 13 project beyond the ends of the upper tubes 10 and 11 and form a support. Annular components or the like placed on the lower tubes 12 and 13 can in that way be pushed easily between all the tubes 10 to 13. During a uniform conveying operation, the carrier member 17 pushes the components that are to be demagnetised through the demagnetising zone 9, the components being demagnetised by virtue of the rotary field existing in the demagnetising zone. Depending on the diameter of the components, the handwheel 14 can be used to adjust the distances between the special steel tubes 10 to 13 to the particular dimensions of the components.

Referring now to Figure 2, in one form of adjusting device 16 the handwheel 14 acts by way of first and second bevel gears 20 and 21 on relatively large plate gears or bevel gears 22 and 23, respectively, disposed at two corners of the demagnetising frame 2. For that purpose the bevel gears 20 and 21 are connected rigidly to one another and to the handwheel 14 by a first drive shaft 24.

Two further relatively large plate gears or bevel gears 31 and 32 are located at the other two corners of the demagnetising frame 2. The large gear 31 is driven -by a further drive shaft 25 on which are mounted a bevel gear 27 in mesh with the large gear 22 and a bevel gear 28 in mesh with the large gear 31. The large gear 32 is similarly driven from the large-gear 23 through a bevel gear 29, a further drive shaft 26, and a bevel gear 30.

A bevel gear 34 secured to a threaded rod 33 engages the large gear 22. The thread 35 of the threaded rod 33 engages an internal thread in a connecting rod 36 to which the special steel tube 10 is secured.

The tubes 11 to 13 are similarly secured to connecting rods 37 to 39, respectively, with internal threads engaged by threaded rods to which are secured bevel gears that engage the large gears 23, 32, and 31, -20 respectively. If the handwheel 14 is turned, the large gear 22 and thus also the bevel gear 34 turn, with the result that the threaded rod 33 moves the connecting rod 36, together with the special steel tube 10, in the direction of the arrow c away from or towards the centre point M through which the central axis 15 extends. Movement of the remaining special steel tubes 11 to 13 in the same sense is effected by way of the corresponding gearwheels, threaded rods and connecting 1 c 1 1 f 11 1 rods.

The connecting rods 36 to 39 are guided and secured against rotation in linear guide members. Such a linear guide member 40 for the connecting rod 37 is 5 shown, by way of example, in Figure 2.

An adjusting device similar to that shown in Figure 2 but having more or fewer than four guide tubes may be used. Instead or in _addition, the adjusting mechanism may be of a design different from that shown 10 in Figure 2.

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Claims (11)

What we claim is:-

1 Demagnetising apparatus having demagnetising coils, arranged around a demagnetising zone, which are fed by a demagnetising generator to produce a rotary f-ield, and parallel guide members that extend through the demagnetising zone symmetrically with respect to a central axis extending through a centre point of the demagnetising zone, and are adjustable centrically in the same sense.

2. Apparatus as claimed in claim 1, wherein the guide members are non-magnetic steel tubes that are arranged in use to rest externally on objects to be demagnetised which objects are located between the guide members.

3. Apparatus as claimed in claim 1 or claim 2, wherein the guide members are arranged to be adjusted together symmetrically by a handwheel or similar adjusting member, or by means of linear motors.

4. Apparatus as claimed in claim 3, wherein the adjusting member acts through drive shafts and gear connecting rods, arranged outside the demagnetising zone that are arranged to move the guide members towards and away from the central axis.

5. Apparatus as claimed in claim 4, wherein the drive shafts actuated by the adjusting member act by way of bevel gears on threaded rods on the threads of which sit the connecting rods connected to the guide members.

1.

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6. Apparatus as claimed in any one of claims 1 to 5, wherein the guide members extend generally horizontally and lower ones of the guide members on which in use objects to be demagnetised rest, project at a feed side of the apparatus relative to upper ones of the guide members.

7. Apparatus as claimed in any one of claims 1 to 6, wherein there are four said guide members.

8. Apparatus as claimed in any one of claims 1 to 7, comprising a conveyor device that in use serves to advance objects that are to be demagnetised along the guide members.

9. Apparatus as claimed in claim 8, wherein the conveyor device has a uniformly driven conveyor chain having a non-magnetisable carrier member that in use engages objects to advance them along the guide members.

10. Apparatus for demagnetising components. especially annular components, having demagnetising coils, arranged around a demagnetising zone, which are fed by a demagnetising generator to produce a rotary field, wherein parallel guide members that are arranged symmetrically with respect to the central axis extending through the centre point of the demagnetising zone and are adjustable centrally in the same sense extend' through the demagnetising zone in the conveying direction.

11. Demagnetising apparatus substantially as here- 1 inbefore described with reference to, and as shown in, Figure 1 or Figures 1 and 2 of the accompanying drawings.

il, Published 1989 atThePatentOfnce, State House, 86171 High Holbornloondon WClR4T?. Further copies maybe obtaJnedfrom The Patentofnee. Sales Branch, St Mary Cray, Orpington, Kent BR5 MLD. Printed by Multiplex techniques ltd, St Mai7 Cray, Kent, Con. 1/87