EP0121009B1

EP0121009B1 - Hanger for parts to be coated

Info

Publication number: EP0121009B1
Application number: EP83301780A
Authority: EP
Inventors: Günter Kistner; Peter Zawiepucha
Original assignee: Deere and Co
Current assignee: Deere and Co
Priority date: 1983-03-30
Filing date: 1983-03-30
Publication date: 1986-06-04
Also published as: EP0121009A1; DE3363900D1; DE121009T1; ZA842355B; ES278486U; ES278486Y

Description

This invention relates to a hanger for parts to be coated under electrical influence, comprising an upwardly inclined prong which projects from a support member and tapers from its root to its distal end. In practice a plurality of prongs preferably project from the same support member.
Such hangers have been used in electro-painting baths. A part to be painted and which has an aperture, is slid over a prong, which is chrome plated for improved electrical contact with the part. The prongs are commonly round in transverse cross-section. However, the contact achieved with this apparatus has not always been sufficient to achieve reliable, high-quality painting.
Moreover, a part hung on a prong, especially a light, mass-produced part, can be dislodged from its prong by the fluid forces acting on the part as the hanger is immersed. For this reason it has been the practice to wire the parts on to the prongs, which is a tedious operation.
It is known from FR 1 333 180 to bend prongs of tapered form out of a stamped, sheet metal support member. Such a structure is inevitably flimsy and does not provide positive engagement with the holes in the parts to be coated which can swing about on the prongs during painting and make the electrical contact unreliable.
It is an object of the present invention to overcome these problems.
The present invention is characterised in that the prong is of triangular transverse cross-section and has sharp, longitudinally extending corners. When a part is placed on a prong the area of contact between the prong and the part is small, but the electrical contact is good. Moreover, the part is securely retained on the hanger and the unpainted area of the part is small.
The invention will now be further described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 shows the hanger with a part to be painted attached to it;
Fig. 2 is a part view along the arrow C of Fig. 1; and
Fig. 3a is a transverse cross-section of a prong along the line A-B in Fig. 1, and Figs. 3b and 3c are transverse cross-sections of other embodiments of prong.

The metal hanger 2 of Fig. 1 comprises a central, box-section spine 4. The spine acts as a support member for prongs 6, a row of which projects from each of the four sides of the spine. The hanger 2 is shown in its orientation for dipping into a colour bath, with its spine 4 vertical, and the prongs 6 constituting a generally upwardly facing array.
Each prong 6 is a sharp-cornered, triangular pyramid. The transverse cross-section of a prong is shown as an equilateral triangle in Fig. 3a.
Parts to be painted, which have an aperture 10, are slid over the prongs to positions such as that of the metal plate 8 in Fig. 1. As is shown by Fig. 2, the prong 6 contacts the inner wall of the aperture 10 of the plate 8 to be painted at the three sharp corners 12 of the prong. The plate may be firmly secured on the prong and a good electrical contact is then provided between the plate and the hanger 2. The hanger 2 is then lowered into the_' colour bath. The painted plate has only three tiny areas left unpainted, at the inner wall of the aperture 10.
Any part may be painted provided it has an aperture which is within the range of sizes of circumcircles defined by the tapering corners of the prongs.
The prongs 6 should be of harder material than the parts to be painted, at least at the corners 12 of the prong. This condition may be achieved in many known ways, for example, using a hanger constructed of a hard metal, surface hardening the hanger or by using a metal which shows considerable work hardening.
In the above example the prongs 6 are shown with sharp ends 14. It may be preferred, for safety reasons, to round off the ends.
It will be appreciated that the invention is not limited to the use of the prongs described. Figs. 3b and 3c show alternative prongs in transverse cross-section, and depict an isosceles triangle and a spherical triangle with concave sides, respectively.

Claims

1. A hanger (2) for parts (8) to be coated under electrical influence, comprising an upwardly inclined prong (6) which projects from a support member (4) and tapers from its root to its distal end, characterised in that the prong is of triangular transverse cross-section, and has sharp, longitudinally extending corners (12).

2. A hanger according to claim 1, characterised in that the faces of the prongs are concave in transverse cross-section.