GB2223210A

GB2223210A - Transport means in material handling system

Info

Publication number: GB2223210A
Application number: GB8813742A
Authority: GB
Inventors: Brian Peter Gimson; Robert Anthony Philpott
Original assignee: TORVALE FISHER ENGINEERING LIM
Current assignee: TORVALE FISHER ENGINEERING LIM
Priority date: 1988-06-10
Filing date: 1988-06-10
Publication date: 1990-04-04
Anticipated expiration: 2008-06-10
Also published as: GB2223210B; GB8813742D0

Abstract

A transport means in a material handling apparatus includes a first transfer unit 17 to transfer an article from an entry station 11 to a holding station 10, a second transfer unit 23 to receive the article from the holding station 10 and to transfer the article to a first intermediate station 26. A further transfer means 28 transfers the articles to a work station e.g. by rotation about a vertical axis, and then back to the intermediate station. The article is then transferred from the intermediate station to an exit station 13. The transfer units 17 and 23 are preferably self-propelled trolleys running on rails 15a, 15b and 51. <IMAGE>

Description

Title: "Material Handling Apparatus" Description of Invention This invention relates to a material handling apparatus.

An object of the invention is to provide a new and improved material handling apparatus.

According to the present invention, we provide a material handling apparatus having a transport means to transfer an article from an entry station to a work station and to transfer the article from the work station to an exit station.

The exit station may be at a position spaced from the entry station and the exit station is preferably at a level below the level of the entry station.

The transport means may include a rotary transfer unit, preferably rotatable about a vertical axis, to transfer the article to and from the work station.

The transport means may include a first transfer unit to transfer the article from the entry station to a holding station, a second transfer unit to receive the article from the first transfer unit and to transfer the article from a first intermediate station to the work station and to transfer the article from the work station to a second intermediate station and a third transfer unit to transfer the article from the second intermediate station to the exit station.

In one more specific aspect of the invention, the holding station constitutes the first intermediate station and the first transfer unit is adapted to transfer the article from the entry station to the first intermediate station whereat the second transfer unit is adapted to receive the article.

In another, preferred, more specific aspect of the invention, the holding station is spaced from the first intermediate station and is disposed between the first intermediate station and the entry station, the first transfer unit being adapted to transfer the article from the entry station to the holding station, a fourth transfer unit being provided to transfer the article from the holding station to the first intermediate station whereat the second transfer means is adapted to receive the article.

The fourth transfer unit may be provided by the third transfer unit.

One of the transfer units may be movable translationally along a predetermined path.

One of the transfer units may be rotatable about an axis which is preferably a vertical axis.

The first transfer unit may be mounted for rectilinear translational movement from the entry station to the holding station.

The second transfer unit may be mounted for rotation about a vertical axis to move the article from the first intermediate station to the work station and from the work station to the second intermediate station.

The third transfer unit may be mounted for translational movement laterally and downwardly away from the second intermediate station towards the exit station.

The third transfer unit may be mounted for rectilinear translational movement laterally away from the second intermediate station to a position spaced therefrom, and then for downward movement and then for further translational rectilinear lateral movement to the exit station.

The third transfer unit may also be mounted for translational movement away from the exit station to a position spaced therefrom followed by upward movement, followed by lateral movement away from the first intermediate station to the holding station.

The first transfer unit may be provided with lifting means to lift an article engaging part into operative engagement with the article at the entry station and to lower the article engaging part out of operative engagement with the article at the holding station.

The third transfer unit may be provided with lifting means to lift an article engaging part into operative engagement with the article at the second intermediate station and to lower the article engaging part out of operative engagement with the article at the exit station.

Means may be provided to operate the lifting means of the third transfer unit at the holding station to move the article engaging part into operative engagement with the article thereat and to lower the article engaging part out of operative engagement with the article at the first intermediate station.

The second transfer unit may be provided with lifting means to permit the article to be lowered from a transfer position, which it occupies during transfer to the work station, to an operative position which it occupies at the work station and then to be lifted from the operative position to a position which is occupies during transfer from the work station.

The second transfer unit may include clamping means to clamp two or more parts of the article together.

The second transfer unit may comprise a cross-head having article engaging means at each end thereof, the cross-head being rotatable about the vertical axis by a drive means.

The second transfer unit may be provided with an indexing means accurately to locate the cross-head and hence the article carried thereby in an operative angular position at the work station.

The indexing means may comprise a pair of interengageable male and female formations, drive means being provided to move them into interengogement when the cross-head is in a position approximating to its operative position so that the cross-head is brought into and maintained in said operative position as a result of mechanical interengagement between the male and female ports.

A casting apparatJs may be provided at the work station, the article comprising a mould having a cavity therein and the mould cavity being disposed in metal transfer relationship with the casting machine when in operative position at the work station.

The casting machine may have means to feed metal upwardly into the mould cavity.

An embodiment of the invention will now be described in more detail, by way of example only, with reference to the accompanying drawings wherein: FIGURE I is a diagrammatic side elevation of part of a material handling apparatus embodying the invention; FIGURE 2 is a diagrammatic side elevation of part of the apparatus of Figure l; FIGURE 3 is a plan view of the part of the apparatus shown in Figure 2, and FIGURE 4 is a diagrammatic plan view to an enlarged scale of the mould at a holding station shown in Figure I illustrating the disposition of support columns for the mould.

Referring to Figure 1, a material handling apparatus 10 has an entry station 11 to which articles to be handled are fed transversely by a conventional feed conveyor 12.

In the present example, each article comprises assembled together cope and drag parts of a sand mould M for metal casting. The apparatus 10 transfers each mould M from the entry station II to a work station W (see Figure 2) where a metal pouring operation is performed to fill the mould M with molten metal. The apparatus 10 then transfers the filled mould to an exit station 13 whereat a conveyor 14 transfers the filled mould away from the apparatus.

The exit station 13 is disposed vertically below the entry station I I and the conveyor 14 may operate in the same direction as the conveyor 12 or may operate in the reverse direction and be disposed directly beneath the conveyor 12, depending upon the layout of the foundry in which the material handling equipment is used.

Extending away from the entry station 11 are a pair of spaced parallel rails 15a supported on a framework 16. Translationally mounted on the rails ISa is a first transfer unit 17 in the form of a trolley having four pairs of wheels, which run on the rails 15a. The trolley is provided with four pairs of wheels 18 arranged as shown so that when the trolley passes over the gap between the rails 15a, and further rails ISb the trolley is supported by at least one wheel adjacent each end, whilst one of the wheels is passing over the gap.

The trolley 17 is provided with a cam operated lift mechanism 19 whereby article engaging means, in the present example four columns 20, are liftable (when the trolley 17 is at the entry station 11) into engagement with a base platen P of the mould M. To locate the mould accurately relative to the trolley as the mould is lifted thereby out of engagement with the conveyor 12 two diagonally oppositely disposed columns are provided with a tapered pin 20a which are received in two corresponding holes 20b in the platen.

At least one of the pairs of wheels 18 is driven by a suitable electric motor so that the trolley 17 can be moved as shown in chain dotted line in Figure 1 from the entry station 11 to a holding station 21 having a holding structure 22 comprising four columns 22a each having a tapered pin 22b for engagement in four correspondingly disposed holes 22c in the platen, onto which the mould is lowered by the lifting means 19. The trolley 17 is then moved bock to the entry station 11 to pick up a further mould which has been fed thereto by the conveyor 12.

When the trolley 17 has moved away from the holding station 21, a further trolley 23, similar to the trolley 17, moves along the rails ISb to the right in Figure I to the holding position and the lifting mechanism 24 thereof, which is similar to the lifting mechanism 19, and has columns 25 corresponding to the columns 20, is operated to lift the mould off the holding structure 22.

The electric motor of the trolley 23 is then operated and the trolley 23 is moved to the left in Figure I until it is at a first intermediate position 26 as shown in Figure 1. The lifting means 24 is then lowered to withdraw the columns 25 from engagement with the platen of the mould and to leave the mould supported on a U-shaped in plan view support frame 27 of an article engaging means of a second transfer unit 28 as shown in Figure I. The frame 27 has four tapered pins 27a which engage in the holes 22c of the platen.

Referrring particularly to Figures 2 and 3, the second transfer unit 28 comprises a pier 30 at the upper end of which is carried a cross-head 31 rotatable about a vertical axis 32 by means of a conventional large diameter anti-friction bearing, commonly known as a "slewing ring". In the particular example described, the bearing is a cross roller bearing but may be of any other suitable kind.

The bearing is provided with an internal gear which is engaged by a pinion 33 driven through a brake and clutch mechanism 33a by an electric motor 33b.

In order to ensure that the cross-head 31 is accurately located at the work station, a mechanical indexing means 55 is provided comprising a generally frusto-conical recess 56 provided on the underside of the cross-head 31 adjacent each end thereof and a correspondingly shaped frustosonicol head 57 is provided carried on the end of a piston rod 58 of a pneumatic cylinder 59.

The electric motor 33b approximately positions the cross-head 31, movement of the cross-head 31 being arrested when limit switches 60 sense the presence of the cross-head and then the cylinder 59 is actuated to move the head 57 into the recess 56. The frusto-conical configuration ensures that the cross-head 31 is rotated as necessary if it is not correctly aligned.

If desired, a head 57 and associated cylinder 59 may be provided on opposite sides of the pier 30 to engage both sockets 56 simultaneously.

At each of its opposite ends, the cross-head 31 carries a mould engaging means comprising a head 34a and 34b. Each head, 34a, 34b, comprises a mould supporting frame 27 having upstanding tapered pins 36 similar to the pins 20 and 25 described hereinbefore for engagement in the four openings 20a in the mould M.

The frame 27 is slidably mounted on four guide rods 37 each having a head 38 at their lower ends. The frame 27 is connected to the piston rods 39 of a pair of pneumatic rams 40 carried on a sub-assembly 42 which is itself vertically slidable on a main frame 41 under the control of two further pneumatic rams 43.

At the work station W there is provided a casting apparatus (not shown) having a riser tube 45 into sealing engagement with which the underside of the mould M is moved, as hereinafter to be described.

Referring now to Figure 1, the rails 15b are carried on a lifting table 50 having a pivoted scissors linkage operated by hydraulic rams to lower the rails I Sb from the dotted line position shown in Figure 1 to the chain dotted line position where they are vertically aligned with further rails 51 which extend to the exit station 13.

In use, a mould M is supplied by the conveyor 12 to the entry station I I.

The first transfer unit 17 is then positioned beneath the mould M and the lifting means 19 operated to lift the mould M off the conveyor 12 and then the first transfer means 17 is moved to the left in Figure I to move the mould to the holding station 21, then the lifting means is operated to lower the mould onto the holding structure 22, the first transfer means 17 is then returned to the entry station ready to pick up a further mould delivered thereto by the conveyor 12.

When the first transfer means 17 has cleared the holding station, the further trolley 23, which in the present example constitutes a third and fourth transfer means, is moved into position beneath the holding structure 22 at the holding station 21 and the lifting means 24 thereof is actuated to lift the mould M off the holding structure 22 and then the trolley, which at this stage constitutes a fourth transfer means, is moved to the left in Figure I until the trolley and mould are at the first intermediate position 26. The lifting means 24 is then lowered to lower the mould M, as shown in dotted line, onto the support frame 27 of the head 34a.

The pneumatic rams 40 are then actuated to clamp the mould between the frame 27 and an abutment surface 27a on the sub-assembly 42. The subassembly 41 is already in a raised position.

The electric motor 36 is then actuated to rotate the cross beam 31 about the axis 32 through 1800 to transfer the mould in a semi-circJlor path to the work station W.

The further pneumatic rams 43 are then actuated to lower the mould M into feeding engagement with the upper end of the riser tube 45 as shown in chain dotted line in Figure 2. Metal is then fed through the riser tube 45 to fill the mould with molten metal.

When the metal has solidified sufficiently to provide a seal at the lower end of the mould, the pneumatic rams 43 are actuated to raise the mould M.

The motor 36 is then energised to rotate the cross-head 31 through a further 1800 to return the mould M to the second intermediate station 26, which in the present example is the same as the first intermediate station.

In the meantime, whilst the head 34a at one end of the cross-head 31 transfers the mould M from the first intermediate position 26 to the work station W, the cross-head 31 transfers a filled mould, held by the head 34b, at the opposite end thereof, from the work station W to the second intermediate station 26. Whilst the first mentioned mould is being filled as hereinbefore described, the following sequence of operations takes place.

The lifting means 24 of the trolley 23 is lifted to engage the filled mould and lift the mould out of engagement with the frame 27. The trolley is then transferred a short distance to the right in Figure I to a position spaced from the second position. This position is shown in chain dotted line at PI.

The pneumatic rams of the table 50 are then actuated to lower the rails 15b to the chain dotted position shown in Figure I and then the trolley motor is actuated to move the trolley to the right in Figure I to move the filled mould Ml to the exit station 13 where the lifting means 24 is lowered to lower the filled mould onto the exit conveyor 14.

During movement of the mould from the second intermediate station to the exit station, the trolley 23 constitutes a third transfer unit.

After the lifting means 24 has deposited the filled mould Ml onto the exit conveyor 14, the trolley 23 is moved to the left in Figure I back onto the rails 15b and the table 50 is again actuated to lift the rails 15b to their dotted full line position shown in Figure I.

The trolley 23 is then moved to the right to pick up a further mould, which, in the meantime, has been transferred from the entry station I I to the holding station 2 I, and transfers it to the first intermediate position 26 where it is engaged with the frame 27 of the mould carrying head 34b which has remained at the first/second intermediate station 26 whilst the above described sequence of operations for moving the already filled mould to the exit station 13 has been performed.

The motor 36 is then actuated to further rotate the cross-head 31 through 1800 and move the new empty mould to the work station 13 and the now filled first mentioned mould M to the second intermediate station 26 for transfer to the exit station as previously described.

By providing the abovedescribed separate trolleys 17 and 23, which constitute a first transfer unit and third/fourth transfer units respectively enables a fast cycle time to be attained.

In the present example, approximately five seconds are required for the second transfer means to transfer a mould from the first intermediate station to the work station, or from the work station to the second intermediate station and approximately two and a half minutes to clamp and unclamp the mould at the first and second intermediate stations respectively.

On the other hand, to fill the mould at the work station takes approximately two minutes and therefore there are two minutes available in which to transfer a filled mould from the second intermediate station to the exit station and to feed a new mould from the entry station to the first intermediate station.

Provision of two trolleys 17, 23 ensures that the necessary transfers are done in this time interval without requiring inconveniently high speeds of operation of the components.

If desired however, only a single trolley may be provided in which case the trolley would pick up a mould at the entry station 11 and feed it directly to the first intermediate station and deposit the empty mould onto the support frame 27. The trolley would then remain at this position to receive the filled mould on the other end of the cross-head 31 and then transfer the filled mould to the exit station as described hereinbefore. The now empty trolley would then be returned to the level of the rails I Sa and then moved to the right to pick up a new, empty, mould at the entry station 11 and transfer the new mould to the first intermediate station 26.

In this case, a single trolley would provide the first and third transfer units.

Although in this embodiment, the first and second intermediate positions correspond, if desired they could be annularly spaced and an appropriate number of trolleys and trackways provided.

Preferably a latch means is provided mechanically to retain the table 50 in its raised position, the latch means being disengaged when it is desired to lower the table.

Appropriate limit switches are provided to ensure that all components are arrested at the desired positions and safety interlocks are provided to ensure that no parts can move if the apparatus is not in the appropriate condition.

The features disclosed in the foregoing description, or the accompanying drawing, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method for attaining the disclosed result, may, separately or any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS:

I. A material handling apparatus having a transport means to transfer an article from an entry station to a work station and to transfer the article from the work station to an exit station.
2. An apparatus according to Claim I wherein the exit station is at a position spaced from the entry station.
3. An apparatus according to Claim 2 wherein the exit station is at a level below the level of the entry station.
4. An apparatus according to any one of the preceding claims wherein the transport means includes a rotary transfer unit.
S. An apparatus according to Claim 4 wherein the transfer unit is rotatable about a vertical axis.
6. An apparatus according to any one of the preceding claims wherein the transport means includes a first transfer unit to transfer the article from the entry station to a holding station, a second transfer unit to receive the article from the first transfer unit and to transfer the article from a first intermediate station to the work station and to transfer the article from the work station to a second intermediate station and a third transfer unit to transfer the article from the second intermediate station to the exit station.
7. An apparatus according to Claim 6 wherein the holding station constitutes the first intermediate station and the first transfer unit is adapted to transfer the article from the entry station to the first intermediate station whereat the second transfer unit is adapted to receive the article.
8. An apparatus according to Claim 6 wherein the holding station is spaced from the first intermediate station and is disposed between the first intermediate station and the entry station, the first transfer unit being adapted to transfer the article from the entry station to the holding station, a fourth transfer unit being provided to transfer the article from the holding station to the first intermediate station whereat the second transfer means is adapted to receive the article.
9. An apparatus according to Claim 8 wherein the fourth transfer unit is provided by the third transfer unit.
10. An apparatus according to any one of Claims 6 to 9 wherein one of the transfer units is movable translationally along a predetermined path.
II. An apparatus according to any one of Claims 6 to 10 wherein one of the transfer units is rotatable about an axis.
12. An apparatus according to Claim 11 wherein said axis is a vertical axis.
13. An apparatus according to any one of Claims 6 to 12 wherein the first transfer unit is mounted for rectilinear translational movement from the entry station to the holding station.
14. An apparatus according to any one of Claims 6 to 13 wherein the second transfer unit is mounted for rotation about a vertical axis to move the article from the first intermediate station to the work station and from the work station to the second intermediate station.
15. An apparatus according to any one of Claims 6 to 14 wherein the third transfer unit is mounted for translational movement laterally and downwardly away from the second intermediate station towards the exit station.
16. An apparatus according to Claim IS wherein the third transfer unit is mounted for rectilinear translational movement laterally away from the second intermediate station to a position spaced therefrom, and then for downward movement and then for further translational rectilinear lateral movement to the exit station.
17. An apparatus according to Claim 16 wherein the third transfer unit is also mounted for translational movement away from the exit station to a position spaced therefrom followed by upward movement, followed by lateral movement away from the first intermediate station to the holding station.
18. An apparatus according to any one of Claims 6 to 17 wherein the first transfer unit is provided with lifting means to lift an article engaging part into operative engagement with the article at the entry station and to lower the article engaging part out of operative engagement with the article at the holding station.
19. An apparatus according to any one of Claims 6 to 18 wherein the third transfer unit is provided with lifting means to lift an article engaging part into operative engagement with the article at the second intermediate station and to lower the article engaging part out of operative engagement with the article at the exit station.
20. An apparatus according to Claim 19 wherein means are provided to operate the lifting means of the third transfer unit at the holding station to move the article engaging part into operative engagement with the article thereat and to lower the article engaging part out of operative engagement with the article at the first intermediate station.
21. An apparatus according to any one of Claims 6 to 20 wherein the second transfer unit is provided with lifting means to permit the article to be lowered from a transfer position, which it occupies during transfer to the work station, to an operative position which it occupies at the work station and then to be lifted from the operative position to a position which is occupies during transfer from the work station.
22. An apparatus according to any one of Claims 6 to 21 wherein the second transfer unit includes clamping means to clamp two or more parts of the article together.
23. An apparatus according to any one of Claims 6 to 22 wherein the second transfer unit comprises a cross-head having article engaging means at each end thereof, the cross-head being rotatable about the vertical axis by a drive means.
24. An apparatus according to any one of Claims 6 to 23 wherein the second transfer unit is provided with an indexing means accurately to locate the cross-head and hence the article carried thereby in an operative angular position at the work station.
25. An apparatus according to Claim 24 wherein the indexing means comprises a pair of interengageable male and female formations, drive means being provided to move said formations into interengagement when the crosshead is in a position approximating to its operative position so that the crosshead is brought into and maintained in said operative position as a result of mechanical interengagement between the male and female parts.
26. An apparatus according to any one of the preceding claims wherein a casting apparatus is provided at the work station, the article comprising a mould having a cavity therein and the mould cavity being disposed in metal transfer relationship with the casting machine when in operative position at the work station.
27. An apparatus according to Claim 26 wherein the costing machine has means to feed metal upwardly into the mould cavity.
28. An apparatus substantially as hereinbefore described with reference to the accompanying drawings.
29. Any novel feature or novel combination of features disclosed herein and/or shown in the accompanying drawings.