GB2065720A - Article holder for use in galvanising process - Google Patents

Abstract

A holder for articles to be galvanised has apertures, for allowing access of molten metal to the articles, in a removeable gate 18 in the holder wall. The holder is adapted for free suspension from a support member or handle 14. Articles are placed in the holder through an opening in the top and are removed from the holder through the bottom by lowering the floor 13 of the holder to create a space between the walls and the floor. The floor 13 slopes outwardly so that the articles scatter as they leave the holder. <IMAGE>

Description

SPECIFICATION Article holder for use in a galvanising process The present invention relates to zinc galvanising and is particularly concerned with improvements in and relating to the process of zinc galvanising in which articles to be galvanised are dipped into the zinc bath in a freely suspended perforated holder or basket, and then spun above the bath in the holder to remove excess zinc from the articles. Such a process is described in British Patent Specifications Nos 1,343,019 and 1,343,120, to which reference should be made for details.

Using the apparatus described in these prior specifications, the articles are quenched while still in the holder by lowering the holder into the quenching bath. Our experience has shown that articles quenched in a confined space still have a tendency to stick together. In an attempt to solve this problem recent apparatus has included a dumper device for holding the basket whilst the spinner motor is detached, after which the dumper mechanism inverts the basket to empty the contents into a quench tank. The disadvantages of this method are, firstly the delay which occurs in placing the basket in the dumper device and detaching the spinner motor can be long enough for the contents of the basket to coagulate.

Secondly the dumper device has to be designed to accept various sizes of baskets. If a variety of baskets sizes is being used on a production run, unacceptable delays can occur whilst adjustments to the mechanism are made.

According to the present invention there is provided a holder for holding articles to be galvanised and having apertures for allowing access of molten zinc to the articles, the holder being adapted for free suspension from a support member, wherein the holder has a closeable opening through which articles can be discharged from the holder without inverting the holder.

The apertures would also allow access to the contents of the holder, in use, of the other fluids used in the galvanising process, such as pickling acid, fluxing solutions and hot air (for drying).

These same apertures permit the free zinc to escape from the basket during the spinning process after basket has been immersed in the zinc bath.

Advantageously the closeable opening extends throughout the entire circumference of the holder.

In one embodiment the floor of the holder slopes outwardly and downwardly and the walls of the holder separate from the floor to form the opening.

Preferably the apertures are formed in a gate which is secured over a window in the wall of the holder, the gate being replaceable. As many windows and gates may be provided as necessary.

The body of the holder may have cross sections of various forms, one version uses a square form, whilst another uses a circular form, but any other regular polygonal shape could be used. Which ever cross section is adopted, all the holders advantageously have walls converging from the bottom giving a tapered form which assists in clearing the contents of the holder during discharge through the open bottom. Contents fall clear from the sloping walls and thus friction is considerably reduced.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which, Figure 1 is a vertical section of a holder according to the present invention, Figure 2 is a section on A-A of Figure 1, Figure 3 is a view from B-B of the bottom part of the central support, Figure 4 is an enlarged plan view of the floor release handle, and Figure 5 is an elevation of the mechanism of Figure 4.

A holder in accordance with the present invention comprises front and rear walls 11 and two side walls 12 which four walls converge from the bottom to form a basket together with a pyramid shaped floor 1 3. The basket has a solid cylindrical carrying handle 14, the top of which has welded to it a plate 1 5 shaped to form a slot 1 6 for engaging a hook by means of which the basket is carried, suspended and spun. The handle 14 is attached to the basket at each end by means of two U-shaped fasteners 1 7 which are welded to the handle around the outside of the handle, and welded to the basket sides. Each wall of the basket has apertures for the access of zinc.These apertures are provided in a gate 1 8 which is bolted at 1 9 to the respective wall 11 or 12 across a rectangular window 20 in the wall. The gate 1 8 comprises two sets of beams 21, 22, each set having its beams parallel to and spaced from one another. The two sets are arranged perpendicular to one another. The size of aperture required will depend on the size of the article which is to be galvanised in the basket. A typical aperture is X inch square. The advantages of this arrangement over the more common perforations are many. A shorter time is required for producing the apertures. Also the gate can readily be replaced if the apertures become clogged with zinc, or if a gate with difference apertures is needed.

The floor of the basket is not connected to the walls 11, 12, but can be lowered to create an opening through which articles can be discharged from the basket. The pyramid floor is freely supported on a square stop plate 23 which itself sits on a square plate 24. The plate 24 is welded to a central bar 25 and supported in position by four triangular ribs 26. The central bar 25 passes through the stop plate 23, through the floor 1 3 at the vertex of the pyramid, through the height of the basket, and has a handle bar 27 at the top by means of which the floor is raised and lowered to open and close the opening.

Two angled support members 28 are arranged centrally in the basket above the level of the floor 13 and around the bar 25. The top of the support members defines a closed position for the handle 27 in which the floor of the basket is closed and fits inside the walls 11, 12. The support members are supported in position by two plates 29, each welded between a respective support member 28 and its adjacent side wall 12. At the top thereof, each support member 28 has one side cut away on an angle as shown in Figure 5, to provide a secure closure position for the handle bar. To open the basket, the handle bar 27 is rotated clockwise through 900. As the handle rides up the slope on the top of the members 28, the floor first moves slightly upwardly, and then the handle 27 can slide down the basket in guides 30 formed by and between the support members 28.As the handle moves downwardly the bar 25 and the plate 24 move downwardly. The stop plate 23 and floor 13 continue to rest on the plate 24, falling with it. The motion is arrested by two angles steps 31 welded to the support members 28 at the bottom thereof and positioned respectively one at the bottom of each of the two guides 30 (see Figure 3). A nut 32 at the top of the handle 27 enables a fine adjustment of the height of the bar 25 to be made before the basket is used. Once the correct height has been determined, the nut is welded in position to fix the height. The central bar 25 is arranged to be long enough so that placing the holder on a flat surface causes the bar to lift slightly off the latching mechanism to permit easier latching or unlatching.While the latching mechanism illustrated utilizes two inclined faces to prevent accidental opening of the iatch, it will be apparent that other methods, such as a bayonet latch or similar method could be employed to obtain the same result.

In use the baskets are loaded with articles to be galvanised through the top, with the floor 13 in the position shown in Figure 1. A hook suspended from the drive of an air motor is passed through the basket slot 16, and the basket and air motor are carried along the process line and raised and lowered by suitable mechanisms. The basket is first dipped in hydrochloric acid to pickle the articles. It is then transferred, using the above mentioned suitable mechanisms, to a drying station. After drying, the basket is dipped into molten zinc until the zinc alloying process with the articles is complete. At any stage in the process, either in or out of the baths, the basket may be spun at speeds varying from 100 to 750 rpm, by the air motor.

The basket is removed from the zinc bath and transferred to a station above the water of a quenching bath. At this point the handle 27 is rotated through 900 and releases the floor 1 3 of the basket. Articles in the basket are discharged through the opening so created at high speed owing to the slope of the pyramid shaped floor.

Because the opening extends around the entire circumference of the basket, the articles are dispersed in all directions and separate while the zinc is still soft, and the zinc only sets on contact with the water. Because of the dispersion articles are less likely than before to be in contact with one another when the zinc hardens and therefore there is an improvement in the success of the process.

A second embodiment, not illustrated, can be used in exactly the same way. This basket is circular in section, and the floor is conical rather than pyramid shaped. In this arrangement the plate 23 has been dispensed with, the floor being supported directly by the plate 24, which is circular. Guides are provided at the edge of the floor to guide the floor into the walls of the basket when the opening is to be closed.

Claims (8)

1. A holder for holding articles to be galvanised and having apertures for allowing access of molten metal to the articles, the holder being adapted for free suspension from a support member, wherein the holder has a closeable opening through which articles can be discharged from the holder without inverting the holder.

2. A holder according to claim 1 wherein the closeable opening extends throughout the circumference of the holder.

3. A holder according to claim 1 or 2 wherein the floor of the holder slopes outwardly and downwardly and the walls of the holder separate from the floor to form the opening.

4. A holder according to any of the preceding claims wherein the side walls converge from the bottom towards the top giving a tapered form.

5. A holder according to any of the preceding claims wherein the apertures are provided in at least one gate, which gate or gates are each removably mounted across a respective gap in the walls and/or floor of the holder.

6. A holder according to claim 3 wherein the floor is raised and lowered by the operation of a handle, fixing means being provided to secure the handle in the closed position of the floor.

7. A holder according to claim 6 including a stop forming the lower position of the handle, in which the floor is open.

8. A holder for holding articles to be galvanised substantially as herein described with reference to the accompanying drawings.