System and machine for strapping articles

Abstract

A system for feeding articles into a processing machine via a feeding railway, the system further comprising: a supply railway intersecting the feeding railway at a crossroads; a supply stand at the end of the supply railway and a crossroads stand at the crossroads, the stands being adapted to receive a pallet with an article in a position bridging the railways; a supply carriage adapted to pass freely under a pallet received in any of the stands, to take it from the stand and to move it to another stand; and a feeding carriage adapted to pass freely under a pallet received in the crossroads stand, to take it from the stand and feed it into the processing machine.

Description

FIELD OF THE INVENTION

This invention relates to means for strapping articles, in particular to automated transport systems for feeding articles into a strapping machine.

BACKGROUND OF THE INVENTION

Packaging of glass sheets is a labor-consuming job. Typically, stacks of glass sheets are transported by forklift trucks from the production line to a packaging area where they are manually encased in wooden cases or frames. The cases are then manually strapped in tensioned strap loops by means of hand-held devices providing controlled tension and bonding of the straps. The process is time-consuming, the positioning and the tensioning of the straps are not always accurate and uniform.

Automated strapping machines are used in other areas of mass-production such as building blocks, bricks, slabs or tiles. Such machines, for example SIGNODE® vertical or horizontal strapping machines, automatically feed the strap from a wheel along a closed frame to form a loop, then position a stack of blocks in the frame, tension the strap loop about the stack, bond the ends of the loop and cut the bonded loop off the wheel. Strapping of the above products does not require particular accuracy of strap positioning or tensioning.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, there is provided a system for feeding articles into a processing machine, such as stacks of glass sheets, into a strapping machine. The articles have length, width and height, and each article is supported on a pallet along the length. The processing machine is adapted to receive the articles moving along a first axis in an orientation where the length is parallel to the first axis. The system comprises:

a) a supply railway transverse to the first axis;

b) a feeding railway along the first axis;

c) a crossroads at the intersection of the supply and the feeding railways allowing through passage along both railways;

d) a first supply stand built at a first end of the supply railway and adapted to receive the pallet in a position bridging the supply railway, with the article in said orientation;

e) a crossroads stand built at the crossroads and adapted to receive the pallet in a position bridging both the supply railway and the feeding railway, with the article in said orientation;

f) a supply carriage adapted to run along the supply railway, to pass freely under the pallet received in the supply stand or in the crossroads stand, to take the pallet from the supply stand, to carry it and to leave it on the crossroads stand;

g) a feeding carriage adapted to run along the feeding railway, to pass freely under the pallet received in the crossroads stand, to take the pallet from said crossroads stand and to feed it into the processing machine for processing the article supported on the pallet;

The system includes an automated control system to control movements of the carriages.

Each of the carriages has a moveable platform which, in lowered position, allows the carriage to pass under the pallet received in any of the stands. By moving to a raised position, the platform allows lifting the pallet from any of the stands and carrying it past any of the stands. By moving to the lowered position, the platform can leave the pallet on any of the stands.

The supply railway may be extended beyond the crossroads and a second supply stand may be built at the second end of the supply railway. At least one additional supply stand may be built between the crossroads and either or both the first and the second supply stands, such that additional pallets may be simultaneously positioned on these additional supply stands by means of the supply carriage.

The feeding railway may be extended to an operative area of the processing machine and preferably to an unloading area beyond the processing machine. The feeding carriage may be adapted to carry the pallet with the article thereon to the operative area and to preferably to the unloading area.

The articles may have a length considerably greater than their width or their height, in particular flat boxes with width considerably less than the height. However, the feeding system may work also with articles having width greater than the height.

The articles are preferably supported in the pallet with their height essentially vertical. The article may be a stack of sheets, such as glass sheets.

The stack of sheets may be encased in wooden or another case.

Among the advantages of the feeding system of the present invention are:

saving space owing to the unique transverse disposition of the two railways;

accurate positioning of the pallets/articles on the carriages and in the processing machine;

creating a stock of articles on the additional supply stands for flexible synchronization of the supply rate of articles with the processing rate of the processing machine;

effective use of only two carriages for moving, stocking and feeding pallets with articles;

automation of the feeding process;

the arrangement is simple, modular and allows adding more components by simply extending the railway or building more crossroads.

In accordance with another aspect of the present invention, there is provided a strapping machine for strapping articles by placing a strap about an article, tensioning and bonding the strap in a closed loop lying substantially in one strapping plane. The article has a first and a second transverse axes and dimensions in the strapping plane. The machine comprises a first carriage carrying a strapping head, adapted to move along the first axis and to transport operatively the strapping head from an initial position remote from the surface of the article to a first contact position with the surface, so that the strap can be tensioned about articles with varying first dimension.

The machine further comprises a second carriage movable along the second axis and adapted to support the strap and to transport it from an initial position remote from the surface of the article to a second contact position with the surface, so that the strap can be tensioned operatively about articles with varying both first and second dimensions.

The machine may further comprise a third carriage movable in the strapping plane and adapted to transport a portion of the strap from an initial position remote from the surface of the article to a third contact position with the surface, thereby ensuring more precise positioning of the strap on the article.

Preferably, the first axis is approximately horizontal and the second axis is approximately vertical.

The machine as a whole may be adapted for limited motion along an axis perpendicular to the strapping plane, for example, by a pneumatic cylinder. Thus, two or more adjacent straps can be placed on the article in one transport cycle by simply displacing the machine along the length of the article.

The strapping machine of the present invention provides for rapid and reliable strapping of articles along a contour with two variable dimensions (width and height) without any adjustment. The positioning of the contour along the third dimension (length) of the article may be provided by the motion of the transport carriage, so in fact the strapping machine is capable of operatively strapping any sequence of articles with all three dimensions varying from article to article. Moreover, a single article with varying contours of strapping along its length may be strapped as well, for example a stepped shape or tapered shape.

The strapping machine also provides for more accurate positioning of the straps on the article—about 5 mm tolerance or better. Thus, the following risks can be avoided or minimized:

jamming of the strap in the strapping head and damage to the article or machine;

tearing of straps while transporting a box to the warehouse and damaging the box, especially breaking of a strapped wooden frame with glass sheets.

Furthermore, the outer appearance of the accurately strapped articles is more aesthetic and commercially appealing.

The usage of the feeding system of the present invention with the strapping machine of the present invention is especially advantageous. The feeding carriage provides accurate positioning of the article, about 5 mm, so that the article can be strapped directly on the carriage, without further adjustment with respect to the strapping machine. This is important for sensitive, fragile and slippery objects such as glass sheets.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic layout of the feeding system of the present invention;

FIG. 2 is a side view of a feeding carriage used in the feeding system of FIG. 1;

FIG. 3 is a sectional view of the feeding carriage of FIG. 2 and a crossroads stand;

FIG. 4 is a schematic elevation view of the strapping machine of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

With reference to FIG. 1, the feeding system 10 of the present invention comprises a supply railway 12 and a feeding railway 14 intersecting at a crossroads 16, a supply carriage 18, a feeding carriage 20, a supply (loading) stand 22 and a crossroads stand 24. Optionally, the system may have an unloading stand 26 and a plurality of additional supply stands 32a, 32b, . . . 32n and 34, etc. A computerized control system (not shown) including positional sensors, velocity sensors, load sensors, etc. controls the operation of the carriages 18 and 20.

The feeding system 10 is used for inserting (feeding) and positioning stacks of glass sheets 40 supported on pallets 42 in a strapping machine 44. The stacks are typically flat, e.g. their width is considerably less than their length and height (the length and the width are seen in the plan view of FIG. 1). The stacks are encased in wooden cases or frames embracing their width.

The strapping machine 44 requires feeding along the axis Y in FIG. 1 and performs strapping along a contour lying in a plane perpendicular to the axis Y. Consequently, the feeding railway 14 extends along the axis Y. The supply railway 12 is perpendicular to the feeding railway 14. The crossroads 16 provides free passage of the carriages 18 and 20 along their respective railways 12 and 14.

With reference also to FIG. 3, the crossroads stand 24 comprises four pillars 50. Each pillar has a landing pad 52 with guides 54 designed and disposed for receiving the pallet 42 in a position where the pallet bridges both railways 12 and 14. The pillars 50 allow both carriages 18 and 20 to pass therebetween.

The supply stand 22 comprises four pillars 60 with landing pads and guides similar to those in the crossroads stand. However, the pillars 60 are designed to position the pallet 42 bridging only the supply railway 12, and to allow passage of the supply carriage 18.

The additional stands 32 and 34 have similar design to the supply stand 22. The unloading stand 26 is similar to stands 22 or 32 but allows passage of the feeding carriage 20.

The feeding carriage 20 comprises a chassis 70, wheels 72 and 73, electric drives 74, a lifting platform 76, a cable 78 in articulated shield, a controller 80, position and speed sensors (not shown). The chassis 70 has two lifting jacks 81 for raising the platform 76 that are powered synchronously by a motor 86 via gears and transmission shaft 88. The platform is also supported in four linear bearings 82. The platform 76 has guiding cones 84 adapted to enter corresponding recesses 85 in the pallets 42 for alignment of the latter.

The lifting platform 76 and the chassis 70 are designed such that when the platform is in lowered position, the feeding carriage 20 can freely pass under the pallet 42 resting in one of the stands 24 or 26. In a raised position, the platform 76 lifts the pallet 42 clear above the landing pads 52 and their guides 54 so that the carriage 20 can carry the pallet 42 through the same stands.

The supply carriage 18 has a lifting platform 96 and other elements similar to those of the feeding carriage 20 except that their dimensions may differ in accordance with the gauge of the railway 12 and the size of the stacks 40. Consequently, the construction of the carriage 18 and its lifting platform enables free passage of the carriage under the pallet 42 resting on the stands 22, 24, 32 and 34 and free transport of the pallet 42 above the landing pads of the same stands.

The feeding system 10 operates in the following way. An external transport means such as forklift truck 90 brings a pallet 42 with a stack of glass sheets 40 from the production line and leaves it on the supply stand 22 over the supply railway 12. Guides 54 provide for an accurate positioning of the pallet on the landing pads 52. The supply carriage 18 comes along the same railway with its platform 96 lowered and stops under the pallet 42. The platform 96 is then raised and the pallet 42 is lifted off the landing pads 52. The supply carriage 18 carries the pallet 42 to the crossroads stand 24, stops therein and lowers the platform 96 leaving the pallet 42 on the landing pads 52. Then the supply carriage 18 runs back to the supply stand 22 for another pallet.

The feeding carriage 20 comes along the feeding railway 14 with its platform 76 lowered and stops under the pallet 42 in the crossroads stand 24. The platform 76 is then raised and the pallet 42 is lifted off the landing pads 52. The feeding carriage 20 carries the pallet 42 to the strapping machine 44 and positions the pallet 42 with the stack 40 in a predetermined position or positions for strapping. After the strapping is done, the carriage 20 travels further down the railway 14 to the unloading stand 26, stops therein and lowers the platform 76 leaving the pallet 42 on the landing pads. Then the feeding carriage 20 runs back to the crossroads stand 24 for another pallet 42 which, in the meantime, had been fetched by the supply carriage 18.

The strapped stack 40′ with its pallet 42 is collected by a forklift truck 90′ from the unloading stand 26.

If, for some reason, the stacks 40 are coming from the production line with greater rate than the strapping machine can handle, the additional stands 32 may be used for accumulating stock in the following way. The supply carriage 18 takes a pallet 42 from the loading stand 22 but the control system finds that the crossroads stand 24 is still busy. The carriage 18 is directed to leave the pallet 42 on the additional stand 32n (the nearest to the crossroads stand 24). The next pallet 42 is then left on the stand 32n-1, etc. When the crossroads stand 24 is freed, the carriage 18 can take the pallet from the stand 32n and put it on the stand 24, and so on.

The additional stand (or stands) 34 may be also used for accumulating stock while the crossroads stand 24 is still free. Another option is to use the stand 34 for performing a technological operation such as assembling a frame or case over the stack of glass sheets 40.

Alternatively, the railway 12 may be equipped with a second loading stand at the side of the additional stand 34, and possibly with a second supply carriage 18. In such case, pallets 42 may be fed to the strapping machine 44 with doubled rate. Furthermore, another feeding railway with another crossroads stand and another strapping machine may be added.

It will be appreciated that the inventive feeding system allows construction of various configurations appropriate to the needs of the production process. Moreover, each such configuration even once built, is rather flexible and can cover wide range of packaging dimensions and production rates. The system also can be easily reconfigured by adding or removing modules such as stands, carriages, feeding railways and strapping or other packaging machines. The system can be used for feeding other processing machines such as washing, painting, coating, shrink-wrap, bottling, filling machines, etc.

With reference to FIG. 4, there is shown a schematic elevation view of the strapping machine 44 of the present invention. The stack 40 to be strapped is shown on the feeding carriage 20 with all its parts numerated as above.

The strapping machine 44 comprises a vertical portal frame 102, a vertical carriage 104, a lateral carriage 106, a bayonet assembly 108, a strap feeder 110 and a control desk (not shown).

The portal frame 102 is disposed over the feeding railway 14 in a plane perpendicular thereto. The frame 102 is supported on wheels 111 rolling along guides 112 parallel to the feeding railway 14. Pneumatic drives 113 provide limited reciprocating displacement of the frame 102 along the guides. The frame 102 further has chutes 114, 116 for conducting packaging strap 120.

The vertical carriage 104 has a drive 122 with transmission located in the frame 102, sensors for detection the height of the stack 40 and chutes 124, 126 for conducting the strap 120. The vertical carriage 104 is adapted to travel vertically along the portal frame 102 and to bring the strap 120 into contact position with the surface of the stack 40.

The lateral carriage 106 also has a drive (not shown), a strapping head 134 and sensors for detection the width of the stack 40. The lateral carriage 106 is adapted to move along a slightly inclined axis X₁ and to transport the strapping head 134 to a contact position with the lateral surface of the stack 40.

The bayonet assembly 108 comprises a bayonet 140 and a drive (not shown) for pulling the strap 120 across the portal opening. In extended position, the end of the bayonet with the end of the strap is received in the chute 116 of the frame. In retracted position of the bayonet 140, the feeding carriage 20 is free to travel along the railway 14 in or out of the strapping machine 44.

The strapping head 134 comprises a tensioning device 144 and a bonding device 148.

Optionally, a third carriage (a second bayonet assembly) 152 may be positioned opposite to the lateral carriage 106, at the other side of the stack 40. This bayonet is adapted to transport a portion of the strap (a loop) 154 into a third contact position with the stack 40 and is similarly equipped with sensors for detecting the opposing surface of the stack 40.

The strapping machine 44 operates in the following way. Initially, the vertical carriage 104 is in uppermost position, the lateral carriage 106 and the bayonet assemblies 108 and 152 are withdrawn so that the portal frame 102 is not obstructed. The feeding carriage 20, carrying a pallet 42 with a stack 40, enters the portal frame 102 along the feeding railway 14 and stops in a predetermined position with respect to the portal 102. The bayonet 140 moves into the receiving chute 116 and the vertical carriage 104 moves down until its sensor detects the stack upper face so as to bring the strap in contact with the upper stack surface. At this time, the strapping head feeds the strap 120 through the bayonet 140 across the portal 102 into the receiving chute 116 and pushes it further through the chutes 114, 126, 124 back to the strapping head 134. There the strap end is caught, and then the strapping head 134 slides slowly until it touches the surface of the stack 40. The system automatically detects the width of the stack by means of a mechanical flap and a sensor. Simultaneously, the second bayonet 152 (if installed) pulls a loop 154 of the strap towards the surface of the stack 40. During the motions of the carriages, the tensioning device 144 takes up the slack of the strap 120 back to the strap feeder 110.

When the strapping head 134 establishes contact with the stack 40, the tensioning device 144 further pulls the strap 120 stronger so as to pull it out of the chutes and tightens the loop about the stack 40 with predetermined tension. Finally, the bonding device 148 bonds the strap loop and cuts the loop off the strap end. The vertical carriage 104, the lateral carriage 106 and the bayonets 140 and 152 return to their initial positions.

If more than one strap loop has to be tightened on the stack 40, the pneumatic drive 113 is operated to displace the portal frame 102 a small fixed distance and another strapping cycle is performed as described above.

The feeding carriage 20 then may move to another position for strapping or may carry away the strapped stack.

It will be appreciated that the strapping machine 44 allows quality strapping of stacks or boxes with three variable dimensions without interruption for readjustment. For example, in a glass production factory, such machine straps stacks of glass sheets in variety of sizes, from 450×1000 mm to 2800×3800 mm, where the width of the stack (thickness) may vary between 120 and 900 mm.

Although a description of specific embodiments has been presented, it is contemplated that various changes could be made without deviating from the scope of the present invention. For example, the strapping machine may be modified for strapping in a horizontal plane, the strapping head may be carried by the vertical carriage instead of the lateral, drives may be hydraulic or electric, etc.

Claims

1. A system for feeding an article supported on a pallet into a processing machine along a first axis, the system comprising:

a) a supply railway transverse to said first axis;

b) a feeding railway along said first axis;

c) a crossroads at the intersection of said supply and said feeding railways allowing through passage along both railways;

d) a first supply stand built at a first end of said supply railway and adapted to receive said pallet in a position bridging said supply railway;

e) a crossroads stand built at said crossroads and adapted to receive said pallet in a position bridging both said supply railway and said feeding railway;

f) a supply carriage adapted to run along said supply railway, to pass freely under said pallet when received on said supply stand or on said crossroads stand, to take said pallet from said supply stand, to carry it and to leave it on said crossroads stand;

g) a feeding carriage adapted to run along said feeding railway, to pass freely under said pallet when received on said crossroads stand, to take said pallet from said crossroads stand and to feed it into said processing machine.

2. The system of claim 1, wherein each of said carriages has a platform moveable between a lowered position allowing said carriage to pass under said pallet received in any of the stands, and a raised position allowing said carriage to lift and carry said pallet past any of the stands.

3. The system of claim 1, wherein said supply railway is extended beyond said crossroads and a second supply stand is built at the second end of said supply railway.

4. The system according to claim 1, wherein at least one additional supply stand is built between said crossroads and said first supply stand, such that a pallet with said article may be positioned on said at least one additional supply stand by means of said supply carriage.

5. The system of claim 1, wherein said feeding railway passes via an operating area of said processing machine and/or is extended beyond said operating area to an unloading area.

6. The system of claim 5, wherein said feeding carriage is adapted to carry said pallet with said article to said operating area or to said unloading area.

7. The system of claim 1, wherein said length is considerably greater than the width or the height of said article.

8. The system of claim 7, wherein said article's width is considerably less than said height.

9. The system of claim 8, wherein said article is a stack of sheets.

10. The system of claim 9, wherein said sheets are glass sheets.

11. The system of claim 10, wherein said stack of sheets is encased in a case.

12. The system of claim 11, wherein said case is wooden.

13. The system of claim 1, wherein said processing machine is a strapping machine for packaging said articles.

14. The system of claim 13, wherein said strapping machine is adapted to place a strap about said article, to tension and bond said strap in a closed loop lying in a strapping plane transverse to said first axis, said machine comprising a first carriage adapted to move along the article's width and to transport a portion of said strap from an initial position remote from the surface of said article to a first contact position with said surface, said machine further comprising a second carriage adapted to move along the article's height and to transport a portion of said strap from an initial position remote from the surface of said article to a second contact position with said surface, one of the two carriages carrying a tensioning head, so that said strap can be tensioned operatively about articles with varying both width and height.

15. The system of claim 14, wherein said article is a stack of glass sheets.

16. The system of claim 14, wherein said strapping machine is adapted to strap said article without removing it from said feeding carriage.

17. A strapping machine for strapping articles by placing a strap about an article, tensioning and bonding said strap in a closed loop lying substantially in one strapping plane, said article having a first and a second transverse axes and dimensions in said strapping plane, said machine comprising a first carriage carrying a strapping head, adapted to move along said first axis and to transport operatively said strapping head from an initial position remote from the surface of said article to a first contact position with said surface, so that said strap can be tensioned about articles with varying first dimension,

wherein

said machine further comprises a second carriage movable along said second axis and adapted to support and to transport a portion of said strap from an initial position remote from the surface of said article to a second contact position with said surface, so that said strap can be tensioned operatively about articles with varying both first and second dimensions.

18. The strapping machine of claim 17, wherein said first axis is approximately horizontal and said second axis is approximately vertical.

19. The strapping machine of claim 17, wherein said first carriage has a means for automatic detection of the distance between said initial position of the strapping head and said contact position.

20. The strapping machine of claim 17, further comprising a third carriage movable in said strapping plane and adapted to transport a portion of said strap from an initial position remote from the surface of said article to a third contact position with said surface.

21. The strapping machine of claim 17, further comprising driving means for operatively displacing said machine along an axis perpendicular to the strapping plane, relative to said article.

22. The strapping machine of claim 21, wherein said driving means include a hydraulic or pneumatic cylinder.