GB2291027A - A steel fabrication system and conveying arrangement - Google Patents

Abstract

A system for fabricating steel has racks (2) for storage of raw material for individual jobs. The system is particularly suitable for a large number of small jobs. Flexible conveyor out-feed systems (6) are provided for delivery of individual items to different destinations using cross-conveyor runners 9 and chain drives (10) as appropriate. A similar conveyor system is provided at the out-feed of a multi-head drill station in which individual lengths may be easily set while the previous workpiece is being drilled. Quick punching of small steel items is achieved by use of a template and a moving carriage and comprehensive shot blasting of fabricated steel is provided by use of a shot blasting machine having an upper wheel for delivery of a shot blast from a vertical direction. <IMAGE>

Description

"A Steel Fabrication System" The invention relates to a steel fabrication system and more particularly to a system for fabricating steel for the construction industry.

The steel fabrication operations which are involved in fabricating steel for the construction industry include cutting, drilling, punching, welding, sub-assembly, surface preparation and surface treatment. Various items of plant have been developed for carrying out these operations and these are particularly suitable for highvolume production of "standard" items. In this scenario, there are large batch runs through individual machines and items are subsequently welded to produce the final product. In this situation it is relatively straightforward to pre-set the machines to operate efficiently.

Examples of the prior art machines include a guillotine as described in British Patent Specification No. GB1179182, a shot blast machine described in British Patent Specification No. GB-A-2084910 and a punching machine described in British Patent Specification No. GB1192769.

There are, however, situations where the commercial requirements of a steel fabrication system are for output of a large number of small batches of fabricated steel.

This arises where there are contracts for relatively small projects from a large number of builders, and also where there is a large project in which the steel is supplied on a piece-meal basis. Because of its weight and bulk steel is a very awkward material to handle and accordingly, if the fabrication system does not operate efficiently where there is a large number of small batches, then the fabrication business may not be viable.

The invention is directed towards providing a steel fabrication system which provides a large degree of flexibility so that small jobs can be handled efficiently.

A still further object is that quality of the end products be of a very high standard.

According to the invention, there is provided a steel fabrication system comprising: a set of raw materials and storage racks for storage of all steel beams for a particular fabrication job; an overhead conveyor mounted between the storage racks and an in-feed system for a cutting machine; a cutting machine communicating with the in-feed system; an out-feed system for the cutting machine, the out-feed system comprising a pair of longitudinal conveyor sections interconnected by a cross conveyor, the cross conveyor comprising cross runners having a rail of relatively soft upper material and a drive means for moving the runners between a lower inoperative position and an upper operative position above the level of rollers of the conveyor sections, the cross conveyor further comprising a workpiece drive means;; a multi-head drill station communicating with the cutting station out-feed system; a shearing station communicating with the cutting station out-feed system; a punching and sub-assembly preparation station communicating with the cutting station out-feed system; a welding table connected by a conveyor means to a shot blast in-feed system; a shot blast machine; and racks mounted for coating of fabricated steel after shot blasting.

Ideally, the cross conveyor runner drive means comprises a pneumatic bellows.

In one embodiment the cross conveyor runner is driven by the bellows to rotate about a pivot pin at one end.

In another embodiment the workpiece drive means comprises a chain carrying a drive dog for the workpiece.

In a still further embodiment the multi-head drill station comprises a workpiece stop member at the end of an hydraulic ram, and a conveyor having a two-speed motor for initially quickly driving the workpiece and for finally moving the workpiece at a relatively slow speed to a final position against biasing ram pressure.

Preferably the cutting station out-feed system comprises a means for raising the level of the final roller mounted for feeding workpieces to the multi-head drill station for improved traction.

In another embodiment the multi-head drill station comprises a clamp having top and side clamping members.

Ideally, the system further comprises a drill station outfeed system comprising a pair of longitudinal conveyor sections and an interconnecting cross conveyor.

In another embodiment, the shearing station and the punching and sub-assembly preparation stations are combined with a common power source.

Ideally, the system further comprises a trolley having a support structure for support of large steel beams for transporting the beams between crane pick-up points.

In a further embodiment the shot blasting machine comprises an upper wheel for delivery of shot blast from a vertical direction for comprehensive shot blasting of fabricated steel items.

The invention will be more clearly understood from the following description of some preferred embodiments thereof, given by way of example only with reference to the accompanying drawings in which: Figs. 1 to 3 and 5 are schematic plan views showing the overall layout of a steel fabrication system of the invention and Fig. 4 is a diagrammatic side view showing the manner in which steel is transported between different bays housing the system; Fig. 6 is a perspective view showing a cutting station out-feed conveyor system; Fig. 7 and 8 are perspective and diagrammatic cross-sectional views showing operation of the out feed mechanism in more detail; Fig. 9 is a perspective view showing operation of a multi-head drilling station; Fig. 10 is a perspective view showing a shearing station; Fig. 11 is a front view of the shearing station;; Fig. 12 is a perspective view showing shotblasting and treatment stations forming part of the system; and Fig 13 is a perspective view showing shotblasting and treatment stations forming part of the system.

Referring to the drawings, and initially to Figs. 1 to 5 there is shown a system of the invention for steel fabrication. The system comprises a set of storage racks 1 for individual storage of steel raw material for particular jobs or contracts. A set of raw material 2 is shown in Fig. 1. An overhead crane 3 is provided for transporting items of steel to an in-feed conveyor 4 for a cutting station 5. The system also comprises a cutting station out-feed system 6. This system provides a large degree of versatility by virtue of the fact that it has two longitudinal conveying sections 6(a) and 6(c) which are interconnected by a cross conveyor system 6(b). The longitudinal section 6(c) acts as an in-feed for a multihead drilling station 12. The longitudinal section 6(a) acts as a supply for other operations such as shearing (primarily for lower-gauge steel).

In more detail, each of the conveyor sections has a set of steel rollers 7 and associated drive motors and chains.

There is also a set of cross-runners 8 within each conveyor section 6(a) and 6(c) and a set of cross-runners 9 extending between them. Three chain drives 10, are mounted between the longitudinal conveyor sections for movement of a steel workpiece 11 between the two of them.

Operation of this system is described in more detail below. From the overall perspective, an important aspect of the conveyor system 6 is that it provides versatility, particularly for small batches as separate decisions may be made regarding transporting individual items of steel, depending on the nature of the contract.

Referring now to Fig. 2, there is shown a drill station output system 15 which has longitudinal conveyor sections 15(a) and 15(c) and an interconnecting cross-conveyor 15(b). Parts similar to those described with reference to Fig. 1 are identified by the same reference numerals. The drilling multi-head drilling station 12 comprises a base 17 having a scale marked on it and a control ram 17 moving on a carriage 19 on the base 17. The drilling head of the station 12 is indicated by the numeral 16. Again, versatility is provided by the choice of individual output directions for the multi-head drilling station 12.

Operation of this station is described in more detail below.

Various work tables (not shown) are provided for stamping the workpiece with a job number after it has been drilled.

This confirms a provisional marking which is made at the cutting stage.

A multi-purpose fabrication station 25 is shown in Fig. 3 to which items of steel are transported either with or without drilling. The station 25 is particularly suitable for angle irons and for small channel-sections. An infeed conveyor 26 feeds longitudinal sections to the station 25, whereas a work bench and associated racks 27 provide small items of raw material. The station 25 comprises a shearing head 28 and a punching sub-station 30 which has a punch head 31. Movement of the workpiece under the punch head is controlled as described in more detail below according to movement of a spring-biassed guide pin 33 located within apertures in a template 32.

Steel beams which have been cut, drilled or sheared then have small items of steel tack-welded to them at the correct locations. Where necessary, a stand-alone punch machine having a deep support for the punching head is used for access to awkward places such as where there are wide flanges.

An overhead crane (not shown) is used for transporting the steel beams with the tack-welded steel pieces to the end of a bay where they are transported by a trolley 40 shown in Fig. 4 to an adjacent bay in which the direction of workflow is opposite to that of the first bay. This bay is shown in Fig. 5 in which there is an overhead crane 51 for movement of the workpieces along the length of the bay. In addition, there are three welding stations (only one of which is shown) 52 where final welding of the fabricated steel structure takes place. This welding takes place after an initial quality inspection with reference to the technical specification.

The crane 51 is arranged to transport the workpieces to the in-feed conveyor of a shot blasting station 53. This station has a fifth, overhead, wheel for direction of shot blast at the workpiece for improved effectiveness, particularly because the workpieces have already been fabricated at this stage. The racks 54 are provided adjacent an out-feed of the shot blasting station 53 for coating of the fabricated steel before delivery. The final product is indicated by the numeral 55 and there is a trailer 56 for transporting the final product away.

Referring now to Figs. 6 to 8 inclusive, the conveyor system 6 is shown in more detail. Parts similar to those described with reference to the previous drawings are identified by the same reference numerals. When the workpiece is being conveyed in the longitudinal direction, the runners 8 are at a low level, below the top level of the rollers 7. Further, the chain drive 10 is not operational. When material is to be conveyed across from one conveyor section to the other, the chain drive 10 is operated so that a dog 60 mounted on the chain pushes the beam across. However, before this happens the runners 10 are raised by a bellows 61 supplied from a pneumatic pipe 62 so that they are above the level of the rollers 7.

This movement is a pivoting movement about a pin 63 and an L-shaped stop member 64 is provided to control and movement. It has been found that this is a particularly effective and quick way to raise the level of the runners for quickly cross-transporting workpieces on an individual basis without any appreciable reduction in efficiency.

Further, the runners 10 are lined with wooden laths to ensure that the beams are not damaged. The system 6 provides for the direct conveying of cut beams directly to other areas such as work areas for tack-welding and also the shearing station 25.

Referring now to Fig 9, the multi-head drilling station is illustrated in more detail. The ram 19 has a rectangular stop member 65 which engages the end of the workpiece 11 as it is conveyed through by the conveyor section 6(c). The motors of the conveyor section 6(c) are controlled to initially drive the piece at a fast rate and then to switch over to a slower speed for final movement of the workpiece 11 against biasing pressure of the ram 18. The position shown in Fig. 9 is where the workpiece 11 is moving at a faster speed towards the static part of the ram 18. When the workpiece reaches to within approximately 20cm of the static part of the ram 18, the speed changes over to a slower speed for final movement of the stop member 65 to the fixed part of the ram 18. The ram 18 had previously been set to the correct distance by movement of the carriage 19 on the base 17.Improved traction for movement of the beam into the drilling station 12 may be provided by raising the last conveyor roller 7 of the conveyor section 6(c). When the workpiece has reached the correct location, it is clamped in position by a clamp 66 having vertical clamping members 67 and a top clamping member 68 so that it is comprehensively clamped in all directions. Efficiency is provided in particular by the fact that while drilling is taking place the carriage 19 may be moved to the correct setting for the next item.

Movement of the workpiece into and out of the drilling station 12 is facilitated to a large extent of use of slip clutches for the conveyor motors to provide automatic reduction in feed rate.

Referring now to Figs. 10 to 12 the multi-purpose fabrication station 25 is shown in more detail. The shearing head 28 comprises a pair of guides, namely a guide 70 for angles, and a guide 73 for channels. There is an out-feed conveyor 72 for the angle irons and an outfeed conveyor 74 for the channel sections. Apertures within the guides 70 and 73 provide versatility in the sizes of sections which are fed through it. A ram 71 is provided for clamping of workpieces in the guide 70 and a ram 75 for clamping of the workpieces in the guide 73.

The multi-purpose station 25 also comprises the punching sub-station 30 which has a punching head 31. An important aspect of operation of the punching head 31 is that the workpiece 84 is located precisely by movement of the biased guide pin 33 on a carriage 80 in the directions 82 and 83 according to the location of apertures in the reference template 32. This allows a very quick and precise positioning of the workpiece for punching at the punch head 31 and the final product, for example, may be the workpiece 85, also shown in Fig. 12. It has been found that by use of the sub-station 30 for fabrication there is relatively little transport and material handling involved for the tack welding operation which are carried out after shearing and drilling.Further, there is a very large degree of versatility provided in the manner in which punching is carried out and there is very quick change-over between different templates. This allows efficiency for small job runs.

The shot blasting machine 53 is shown in detail in Fig.

13. An important aspect of the machine 53 is that it comprises a two side shot blasting wheels and a fifth top wheel for very comprehensive access to all parts of the fabricated steel. This provides for comprehensive shot blasting in this situation, where the steel is prefabricated before the shot blasting operation.

Heretofore, it has been common to shot blast the steel sections before fabrication because of problems of access to awkwardly-positioned surfaces. The fact that the coatings area 54 is located next to the out-feed of the machine 53 allows a coating to be applied within two hours of shot blasting to help ensure that there is no deterioration in the steel. Coating is carried out by hand spray guns and again this provides versatility for different sized workpieces.

It will be appreciated that the invention provides a system which is extremely flexible as it allows efficient fabrication of small job lots with very quick turnaround times between jobs. These advantages are achieved by use, for example, of the storage racks for individual lots of raw material, and the particular transport mechanism which provides flexibility and efficiency in transport of the steel between the work stations. The particular manner in which the multi-head drilling may be carried out whereby there is improved traction, efficient guiding of the workpiece and effective clamping help to provide for efficiency and flexibility. This is also provided by the location and nature of the shearing and punching stations and indeed by the construction of the shot blasting machine whereby shot blasting may be carried out after fabrication of the steel.

The invention is not limited to the embodiments hereinbefore described, but may be varied in construction and detail, for example, a gas cutting station may be incorporated, which station would have the ability to cut a beam or other piece at any desired angle. Further, the saw may incorporate a measuring arm.

Claims (13)

1. A steel fabrication system comprising: a set of raw materials and storage racks for storage of all steel beams for a particular fabrication job; an overhead conveyor mounted between the storage racks and an in-feed system for a cutting machine; a cutting machine communicating with the in feed system; an out-feed system for the cutting machine, the out-feed system comprising a pair of longitudinal conveyor sections interconnected by a cross conveyor, the cross conveyor comprising cross runners having a rail of relatively soft upper material and a drive means for moving the runners between a lower inoperative position and an upper operative position above the level of rollers of the conveyor sections, the cross conveyor further comprising a workpiece drive means; a multi-head drill station communicating with the cutting station out-feed system;; a shearing station communicating with the cutting station out-feed system; a punching and sub-assembly preparation station communicating with the cutting station out-feed system; a welding table connected by a conveyor means to a shot blast in-feed system; a shot blast machine; and racks mounted for coating of fabricated steel after shot blasting.

2. A system as claimed in claim 1, wherein the cross conveyor runner drive means comprises a pneumatic bellows.

3. A system as claimed in claim 2, wherein the cross conveyor runner is driven by the bellows to rotate about a pivot pin at one end.

4. A system as claimed in any preceding claim, wherein the workpiece drive means comprises a chain carrying a drive dog for the workpiece.

5. A system as claimed in any preceding claim, wherein the multi-head drill station comprises a workpiece stop member at the end of an hydraulic ram, and a conveyor having a two-speed motor for initially quickly driving the workpiece and for finally moving the workpiece at a relatively slow speed to a final position against biasing ram pressure.

6. A system as claimed in claim 5, wherein the cutting station out-feed system comprises a means for raising the level of the final roller mounted for feeding workpieces to the multi-head drill station for improved traction.

7. A system as claimed in claims 5 or 6 wherein the multi-head drill station comprises a clamp having top and side clamping members.

8. A system as claimed in any preceding claim, further comprising a drill station out-feed system comprising a pair of longitudinal conveyor sections and an interconnecting cross conveyor.

9. A system as claimed in any preceding claim, wherein the shearing station and the punching and sub assembly preparation stations are combined with a common power source.

10. A system as claimed in any preceding claim further comprising a trolley having a support structure for support of large steel beams for transporting the beams between crane pick-up points.

11. A system as claimed in any preceding claim, wherein the shot blasting machine comprises an upper wheel for delivery of shot blast from a vertical direction for comprehensive shot blasting of fabricated steel items.

12. A system substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.

13. Steel sections whenever produced by a system as claimed in any preceding claim.