Hot dip galvanising is a process particularly suited to applying a protective metal coating on small articles, such as bolts, nuts, nails and screws. In this process, the articles to be galvanised are dipped in a series of chemical treatment material baths as well as at least one bath of molten zinc or other suitable metal for coating the article.

The dipping process can be carried out by hand, but as well as being potentially dangerous to the worker, hand dipping is time consuming and generally inefficient. o Apparatus has been developed to facilitate the process. One such apparatus, as disclosed in Australian patent 542552, includes a barrel in which the articles are held for dipping and subsequent spinning about a horizontal axis to remove any excess treatment liquid from the articles. Even with this apparatus, however, the process is labour intensive and generally inefficient.

An improved holding and transporting apparatus is disclosed in Australian patent 594844 which includes a basket-like receptacle for holding the articles during dipping and subsequent spinning about a vertical axis to remove excess

treatment liquid. This apparatus incorporates an industrial robot which, together with the receptacle mounting arrangement, reduces labour involvement and generally improves dipping efficiency.

A disadvantage of dip treating collection of articles loosely contained in a receptacle is that the treatment liquid sometimes causes ^' the articles to stick together. In addition, spinning of the articles to remove excess liquid from them can cause the articles to collect at the receptacle walls where they may remain "stuck" even when spinning ceases. This may be particularly so in the case of hot dip galvanising small articles, where the zinc coating applied to the articles tends to adhere the articles together and to the receptacle walls. In consequence, removal of the articles from the receptacle may be hampered, and even then the articles may require separation from one another.

It is an object of the present invention to provide an apparatus for holding and transporting articles during their treatment, applicable to hot dip galvanising articles, and which alleviates the foregoing difficulties and disadvantages. With that object in mind, the present invention provides an apparatus for holding and transporting a plurality of discrete, loose articles during dip treatment of those articles in a bath of treatment liquid, including: a receptacle for loosely containing articles during dip treatment, the receptacle having openings therein for free flow of treatment liquid into the receptacle when placed into the liquid and out of the receptacle when removed from the liquid; support means connected to the receptacle for moving the receptacle into and out of the treatment liquid; and,

SUBSTITUTE SHE

vibration means operable to vibrate the receptacle following dipping so as to retain the articles in a loose condition.

Preferably, the vibration means is connected to the support means and operable to vibrate the support means. The support means preferably includes an elongate support shaft connected to the receptacle. Moreover, the vibration means is operable to rapidly longitudinally oscillate the support shaft and thereby vibrate the receptacle.

Preferably, the support shaft is arranged in an upright orientation, and the vibration means includes an actuator device operable to cause alternative lifting and lowering of the support shaft to vibrate the receptacle. The actuator device may be operable to alternatively apply lifting forces to the support shaft to lift the support shaft, and then release the support shaft to allow the shaft to fall under the influence of gravity. With this arrangement, the vibration means preferably includes a damping mechanism to resiliently arrest fall of the support shaft. That mechanism may also apply a return force to the shaft to cause an at least partial lifting. The damping mechanism may include at least one resilient damping member, such as a damping spring.

Preferably, the support shaft is rotatable about a longitudinal axis to spin the receptacle. Moreover, drive means is preferably provided for rotating the shaft about its longitudinal axis.

Preferably, the support shaft is longitudinally movable for moving the receptacle into and out of the bath of treatment liquid. To that end, the support means may further include a guide sleeve in which the support shaft is rotatably mounted, the guide sleeve being longutidinally slidable for

SUBSTITUTE

longitudinal movement of the support shaft.

The following description refers to a preferred embodiment of the apparatus of the present invention. To facilitate an understanding of the invention, reference is made in the description to the accompanying drawings illustrating a preferred embodiment of the apparatus. It is to be understood that the invention is not limited to the embodiment as hereinafter described and as illustrated.

In the drawings: Fig. 1 is a side view of the apparatus according to a preferred embodiment of the present invention; and,

Fig. 2 is an enlarged side view of part of the apparatus of Fig. 1 showing in detail the vibration means of the apparatus.

Referring to the drawings there is generally illustrated apparatus 1 for holding and transporting discrete articles, such as nails, (not shown) while they undergo surface treatment in one or more baths B of the treatment liquid. Although only one bath B is shown it should be appreciated that two or more baths B may be arranged to receive the articles in succession during a treatment process. Typically, those baths B will be positioned in a side-by-side arrangement adjacent apparatus 1, as will become more apparent hereinafter.

Apparatus 1 includes receptacle 2 in which the article are loosely contained. Receptace 2 includes basket 3 preferably made from perforated sheet or mesh material, such as metal, having openings therein for free flow of treatment liquid into and out of basket 3. Basket 3 has an access opening (not shown) at the top thereof for loading and unloading basket 3 with articles. Conveniently basket 3 is of

SUBSTITUTESHE

circular cross-section.

Apparatus 1 also includes support means 4 through which receptacle 2 is transported. Support means 4 is broadly constructed and arranged to position basket 3 in and retrieve receptacle 2 from baths B.

Support means 4 includes elongate support shaft 5 orientated at least substantially vertically and being rotatable about longitudinal axis X. Shaft 5 has opposite upper end 6, and lower end 7, and at lower end 7 there is provided coupling means (not shown) through which receptacle 2 is connected to shaft 5 for rotation therewith about axis 6.

Shaft 5 is carried by support arm 8 included within support means 4. /In particular, support arm 8 has one free end 9 at which shaft 5 is mounted, with other end 10 of arm 8 being pivotally mounted for swinging, about upright pivot axis Y, in a horizontal plane to effect arcuate movement of support shaft 5 and thus lateral shifting of receptacle 2. With this arrangement a plurality of baths B are usually positioned along an arcuate line equidistant from pivot axis Y so as to enable shifting of receptacle 2 to each bath B.

Support arm 8 is mounted on base structure 11 included in apparatus 1 to elevate arm 8 so that, in use, the horizontal plane in which arm 8 can move is above the top of baths B. The elevation is preferably sufficient to allow a clearance between baths B and receptacle 2 when raised to permit receptacle shifting toward and away therefrom. A motor (not shown) may be housed within base structure 11 and connected directly or indirectly to support arm 8 for pivoting same. Support shaft 5 is also longitudinally movable along

SUBSTITUTESH

axis X in order to raise and lower receptacle 2 relative to bath B. The drawing shows receptacle 2 in a raised position (full line) and a lowered position (chain dot line) . For that purpose support means 4 includes guide sleeve 12 having mounting bracket 13 fixed thereto and slidably mounted in guide block 14 at lower end 9, and rotatably housing support shaft 5. In this way, shaft 5 can be rotated about axis X relative to sleeve 12 in order to rotate receptacle 2, and guide sleeve 12 together with shaft 5 can be longitudinally moved up and down so as to raise and lower receptacle 2.

To effect rotation of shaft 5, apparatus 1 includes drive means 15 located adjacent upper end 6 of shaft 5. Drive means 15 -includes drive motor 16 mounted on bracket 13 for longitudinal movement with guide sleeve 12 and drivingly coupled directly (not shown) or indirectly (as shown) to shaft 5. Coupling of motor 16 and shaft 5 may be by way of drive transmission 17, such as pulleys 18 fixed on motor output shaft 19 and upper end 6 of support shaft 5 and one or more belts 20 interconnecting those pulleys 18. Motor 15 is typically an electrically driven motor. Other motor and transmission arrangements are envisaged as will be appreciated by those skilled in this art.

Longitudinal movement of guide sleeve 12 and support shaft 5 is controlled by actuating member 21. Actuating member 21 preferably incldes piston and cylinder actuator 22 mounted parallel to axis X and connected to sleeve 12. Cylinder 23 of actuator 22 is rigidly mounted at or adjacent one end 9 of support arm 8 while piston rod 24 projects downwardly therefrom and is connected to sleeve 12 through bracket 25. In this way, extension and retraction of piston

TUTES

rod 24, during actuator operation, acts to vertically move sleeve 12 and shaft 5 and thus lower and raise receptacle 2, respectively. Actuator 22 may be hydraulically or pneumatically operated.

To fully automate apparatus operation, an industrial robot may be incorporated into the apparatus, the arm of the robot providing support arm 8. The operating sequence of apparatus 1 may be controlled by the logic circuits of that robot. Control panel 26 may be provided on base structure 11 for controlling operation of motor 16 and actuator 22, as well as movement of support arm 8.

In using apparatus 1, so far described, for hot dip galvanizing articles, a series of baths B (one only shown) containing the prerequisite chemical treatment liquids and metal coating liquids are placed in the correct sequential order of dipping along an arcuate line extending about apparatus base structure 11. The radius of the arcuate line is approximately the distance from pivot axis Y of support arm 8 to longitudinal axis X of support shaft 5. With receptacle 2 containing articles to be galvanized it is raised with support shaft 5 and guide sleeve 12 by operation of actuator 22, and support arm 8 is swung about pivot axis Y to bring receptacle 2 over baths B stopping above each bath B in sequence. At each bath B, receptacle 2 is lowered into bath B for article treatment with the contained liquid. Thereafter, receptacle 2 is raised from the liquid and, while remaining over that bath B, rapidly rotated to remove any excess liquid from the articles and return the liquid to the bath. In this way, apparatus 1 operates to transport the articles through baths B while they are retained

in receptacle 2.

Under the influence of the centrifugal forces during rapid rotation of receptacle 2, the articles may tend to collect at the outer wall of receptacle 2. Sometimes, those articles may remain attached to the wall even when rotation ceases. That is often due to the nature of the article treatment, where coatings may temporarily "stick" the articles together and to the wall of receptacle 2. Because the articles do not remain in a loose condition their removal from

10 receptacle 2 can be difficult.

To alleviate this difficulty, apparatus 1 provides for the vibration of receptacle 2 in order to shake loose any articles collected at the wall of receptacle 2. That vibration may also assist in separating any articles that may have "stuck" together. Thus, the vibration of receptacle 2 ensures that the articles remain loose.

Receptacle 2 is vibrated by rapidly oscillating support shaft 5 to which the receptacle is connected. That oscillation is linear and along shaft 5, so that shaft 5 is

20 rapidly moved back and forth along its longitudinal axis X. This movement is in addition to the shaft movement for moving receptacle 2 into and out of the bath B of treatment liquid.

Support shaft 5 is mounted in guide sleeve 12 for oscillatory movement relative thereto, and also mounted so as to be supported for its rotational movement. To that end, support means 4 includes bearing means 27 mounting support shaft 5 in guide sleeve 12 for its rotational and limited axial movement.

Bearing means 27 is of any suitable construction well

30 known to those skilled in the relevant art. In this

SUBSTITUTESHE

embodiment, bearing means 27 includes one (as shown) or more (not shown) bearing members 28. Bearing members 28 is an axial thrust bearing member positioned to support the load of shaft 5 and receptacle 2, yet permit shaft 5 to move upwardly during shaft oscillation.

Apparatus 1 further includes vibration means 29 to repidly vibrate support shafft 5. Vibration means 29 includes actuator device 30 operable to produce an oscillatory output that is applied to support shaft 5.

Actuator device 30 is of any construction suitable for imparting the necessary forces to support shaft 5 causing rapid vibration thereof.

In this embodiment, actuator device 30 is electrically powered. Device 30 includes electromagnetic device 31, slectively energisable and de-energisable, or recycled, to cause alternate lifting and lowering movements of support shaft 5. In that regard, electromagnetic device 31 is mounted adjacent upper end 6 of support shaft 5, energisation of device 31 lifting shaft 5 and de-energisation allowing shaft 5 to fall under the influence of gravity. In this embodiment, device 31 includes slave plate 32 attached to upper end 6 of shaft 5 and electromagnetically energisable core 33 spaced therefrom, energisation of core 33 magnetically attracting slave plate 32 to core 33, and de-energisation releasing plate 32 therefrom.

Actuator device 30 may, in alternative embodiment (not shown), include a rotary electric motor having an output shaft connected to a drive translation mechanism imparting the vibration generating forces to shaft 5. The translation mechanism in different embodiments includes a cam and follower

mechanism, a crank mechanism or other mechanical mechanism to alternatively lift shaft 5, and lower shaft 5 or allow the shaft to fall.

In another embodiment (not shown) , actuator device 30 is hydraulically or pneumatically fluid powered. That device 30 may include a piston and cylinder or other linear actuator reciprocally movable to cause the alternative lifting and lowering of shaft 5. In that regard, one of the piston or cylinder can be fixed and the other one reciprocally movable under pressure of hydraulic or pneumatic working fluid, that movement being applied to shaft 5. To that end, the movable piston or cylinder may be connected to or impact against shaft 5 causing it to alternatively lift, and lower or fall.

Where, as part of the vibratory oscillations, support shaft 5 is caused to fall under gravity influence then that fall is damped in this embodiment. That damping is arranged to reduce the potential damage to apparatus 1 caused by the falling shaft 5. In addition, the damping may be arranged to facilitate subsequent oscillations of shaft 5. To that end, the damping is resilient so that shaft 5 and receptacle 2 have some tendency to at least partially return move or rebound under reaction or return forces applied directly or indirectly to support shaft 5 during damping.

Damping is provided by samping mechanism 34, which includes at least one resilient damping member 35 arranged to act directly or indirectly on support shaft 5. In this embodiment, each damping member 35 is a damping spring (not shown) or rubber bumper (not shown) . A plurality of such members 35 are provided. in this embodiment, damping members 35 act indirectly on

SUBSTITUTE SHEE

support shaft 5 through bearing member 28 axially supporting support shaft 5 in guide sleeve 12. in that regard, bearing member 28 is mounted on damping members 35, through intermediate support plate 36, with damping members 35 in turn being fixed to guide sleeve 12 through mounting brackets 13. Damping mechanism 34 includes support plate 36 having aperture 37 threrein through which shaft 5 freely extends, plate 36 being carried by damping members 35, and bearing member 28 for axially supporting support shaft 5 in turn being carried by support plate 36.

In using apparatus 1 incorporating vibration means 29, when receptacle 2 has been rotated to remove excess treatment liquid from the articles, vibration means is operated in order to oscillate support shaft 5 and thus vibrate receptacle 2. The number of oscillations and the distance over which shaft 5 is oscillated may vary depending on the application of apparatus 1. In some applications a single oscillation may be sufficient to dislodge the articles from the receptacle wall and separate those articles from one another. In other applications several oscillations may be appropriate. In any event, those oscillations are expected to occur for only a short time period, i.e. for a matter of seconds.

Operation of vibration means 29 may be included into the automatic apparatus operation so that it occurs automatically as part of the operating sequence of the apparatus Alternatively, or in addition, that operation may be manually conducted.

It is to be understood that various modifications and/or alterations may be made to the apparatus without departing from the ambit of the present invention as defined in the claims appended hereto. T EE