EP0123173B1

EP0123173B1 - Assembly line, particularly suited for the production of leather and similar goods

Info

Publication number: EP0123173B1
Application number: EP19840103645
Authority: EP
Inventors: Giuseppe Anzani
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-04-22
Filing date: 1984-04-03
Publication date: 1988-03-23
Also published as: IT8320771A0; EP0123173A2; DE3469989D1; ES8504260A1; KR840008268A; FR2544680A1; IT1161177B; EP0123173A3; PT78460B; MX159355A; FR2544680B1; ES531780A0; KR880002428B1; PT78460A

Description

The present invention refers to an assembly line particularly suited for the production of leather and similar goods.
More in particular, the present invention refers to an assembly line, particularly suited for the production of leather, imitation-leather, hide, fabric, felt, plastics and similar goods, such as footwear, slippers, etc. which allows all the production phases to be completed without unloading and re-loading the product.
Many types of assembly line are known for leather, imitation-leather, fabrics, plastic and similar goods, on which moving trolleys equipped with one or more shelves are anchored by fixed, or releasable coupling devices.
The various components of the goods to be produced are placed on the said shelves at the beginning of the cycle, and are progressively assembled in the successive working stations, aligned along the assembly line.
As an example and in order to further help with the understanding of the present invention, specific reference will be made to the production of footwear, in which assembly lines are presently widely used.
In the specific case the footwear components are placed on the said shelves, such as for example uppers, moulds, inner soles, soles, heels and so on, which are progressively assembled in the successive working stations, aligned along the assembly line.
In correspondence to each of the said stations the operator assigned takes the components that have to be used from the said shelves, mounts them on the portion of the preformed footwear which arrives from the previous station and at the end of the operation, re-loads the footwear obtained onto the same shelves. The trolley that supports the said shelves is then moved to the successive station for another working phase.
A transporter trolley travelling on rails and suitable for transporting footwear in manufacturing plant through a multiplicity of working operations is known from FR-A-1,004,423.
The disclosed transporter trolley comprises a vertical yoke type support frame, vertically oscillating and provided with cross-pieces sustaining the support brackets for the footwear to be treated. Heating means or driers are arranged in sequence along the working line and the footwear are passed through them, mounted on the same transporter trolley. US-A-3,120,666 discloses an assembly line for the production of shoes comprising a movable conveyor line, a plurality of racks on said conveyor line at spaced intervals and heating means positioned beneath and in vertical spaced relation to said conveyor line to heat shoes positioned upon each rack as it moves past the heating means. The heating means comprise a tunnel-like chamber to admit the rack, so that the rack is straddled by the heating means.
The above known assembly lines make it possible to overcome considerable problems regarding the rationalisation of the working stages and of the working environments, the productivity of the systems, the quality of the finished product and production economy, however they are not completely satisfactory, since they do not allow all the treatments foreseen by the process to be performed. Hence, for example, the known assembly lines do not permit the treatments to which the footwear is subjected to be performed at the start of_kthe working phases and after the uppers, the toes, the sides and the heels have been mounted'on moulds and before the phases which include the application of the soles, the heels and so on.
The treatments include humidifications, heating by hot air, seasoning with stretching under vacuum and evacuation of vapours and radiation using infra-red ray heaters, at present these treatments are performed outside the assembly line.
To perform these treatments the footwear is unloaded from the assembly line trolleys and placed inside special ovens, or particularly equipped rooms.
At the end of the treatments, the same footwear is removed from the ovens, or taken out of the said rooms and re-placed on the conveyor belt trolleys.
It is obvious that even if the ovens, or the equipped rooms are normally positioned adjacent to the assembly lines, these loading and unloading operations are lengthy and costly.
A multiple containers device may also be used for the stretching and seasoning phases of leather goods and in particular of footwear.
The said containers, which enter and leave the ovens sequentially, transported by a continuous chain make it possible to substantially reduce the hold-up time of the assembly line trolleys in the treatments station.
However the loading and unloading problem of leather and similar goods from the assembly line remains, these having to be performed manually by an assigned operator.
The object of the present invention is that of providing an assembly line which makes it possible to overcome the above mentioned drawbacks. According to the present invention, an assembly line that makes it possible to perform all the process phases to produce leather, imitation-leather, fabric, plastic and similar goods, without needing to perform any unloading and re-loading operation, comprises a plurality of transporter trolleys travelling on rails for transporting the goods in manufacturing plant through a multiplicity of working operations, and fitted with automatic coupling and release devices, and ovens for humidification, heating, seasoning, stretching under vacuum, evacuation of vapours and radiation, wherein the ovens are arranged beneath the assembly line and in sequential series with the working stations and each transporter trolley is fitted with a vertical support frame, hanging and yoke type and it is straddled by ovens, the characterising parts of which are that:

- each oven is made up to two sliding half-shells which are arranged on opposite sides of the assembly line and are moved away and towards the support frame;
- the doors of the half-shells have a peripheric profile equal to that of the support frames, and
- the two side surfaces of the support frame are parallel to one another and parallel to the surfaces of the oven doors, the seal between the surfaces of the oven doors and the said side surfaces of the frame being ensured by gaskets applied to the sides and to the surfaces of the doors.

Each support frame may be fitted with cross-pieces sustaining the footwear support brackets, or of other supporting means.
The conveyor trolleys may be fitted with one, or more shelves, or vertical trays.
To better understand the functional and structural characteristics of the assembly line, subject of the present invention, a detailed description will be provided here with reference to the figures of the attached drawings which represent several exemplificative, but non-limitative preferred embodiments and in which:

Figure 1 is a perspective view of a particular embodiment of footwear trolleys mounted on the rails of an assembly line;
Figure 2 is a side view of the trolley of Figure 1, partially sectioned, aligned with an oven to treat the footwear, arranged straddling the hanging frame;
Figure 3 represents the schematic and plan view, of a partial assembly line, subject of the present invention fitted with trolleys with a yoke type frame, on which the product treatment stations are aligned and Figures 4, 5 and 6 represent the schematic views of other types of embodiment of conveyor trolleys fitted with a hanging yoke type frame.

With reference to the figures, the assembly line, subject of the present invention includes a large number of conveyor trolleys 1 and ovens 33 and 34 to perform the humidification, heating, seasoning, stretching treatments, etc. foreseen by the production process.
Each conveyor trolley 1 has a supporting structure 2 to which the front shelves, or supporting trays 3 and 4 of a known type are fixed.
The upper 5 and lower 6 wheels, which run along the rails 7 of the assembly line are applied on the structure 2.
The various drawing, release and coupling devices of the trolleys are not illustrated and described here since they are of a known type and do not concern the present invention.
The trays 3 and 4, fixed to the structure 2, may have a single support surface 8, or may be divided into compartments 9 via separators 10.
The upper ends 13 of the uprights 23 are pivoted to the side edges 12 of the upper tray 3 and to a yoke type support frame 14.
Whereas, pins 16 are fixed in correspondence to the side edges 15 of the lower tray 4 inserted in the transversal slits 17 made on the said ends 13.
Therefore, the frame 14 may rotate about its upper fulcrums 18 and oscillate for an amplitude permitted by the length of the slits 17.
Figures 1 and 2 represent trolleys 1 specifically equipped for the production of footwear 21.
Cross-pieces 19 are fixed in the central part of the frame 14 sustaining the support brackets 20 for the footwear 21. The ovens 33 and 34 for the humidifying, the heating by hot air, the seasoning, the stretching, the evacuation of the vapours and the radiation treatments using infra-red ray heaters consist of two sliding half- shells 26 and 27 to enable them to be moved towards and away from one another.
The parallelogram made by the cross-pieces 22 and by the uprights 23 making up the external structure of the vertical hanging support frame 14, forms a peripheric seal ledge for the doors 24 and 25 of the two half- shells 26 and 27.
To achieve the said ledges the above mentioned parallelogram is made using profiles having at least the two side surfaces 28 and 29 in parallel with one another and parallel to the surfaces 31 and 32 of the doors 24 and 25.
As can be noted from Figure 2, the half- shells 26 and 27, forming the ovens, are mounted beneath the assembly line and are arranged on opposite sides of the assembly line.
The vertical hanging frame 14 is straddled by the ovens so that its external structure, formed by the cross-pieces 22 and by the up-rights 23 are perfectly aligned with the doors 24 and 25.
Again with particular reference to the use of the assembly line, subject of the present invention, for the production of footwear, at the beginning of the working phases the uppers are preferably subjected to an initial humidifying, softening and possible radiation treatment using infra-red ray heaters to revive the toe piece, to facilitate the successive assembly phases on the moulds. To do this, the uppers and the relative moulds are positioned on the brackets 20 of the hanging frame 14, at the beginning of the working cycle, while the other components of the footwear are pre-arranged in an orderly way on the trays 3 and 4.
A humidification oven is pre-arranged aligned with the successive working station consisting of two half- shells 26 and 27 fitted with doors 24 and 25 which when moved close together form a seal along the parallel side surfaces 28 and 29 of the frame 14. The half- shells 26 and 27 are moved towards one another by means of hydraulic, or pneumatic pistons of a known type (not illustrated in the figure) when the structure of the handing frame 14 is perfectly aligned with the doors 24 and 25, until the surfaces 31 and 32 of the doors come into contact with those 28 and 29 of the frame 14.
During the translation, the half- shells 26 and 27 travel on transversal guides 30 moved by the hydraulic, or pneumatic cylinders.
At this point the oven closes entrapping the hanging frame 14 containing the uppers 21 to be treated.
The oven seal is ensured by means of rubber gaskets 35, or other suitable material, applied to the edges and over the surfaces 31 and 32 of the doors 24 and 25.
During the oven treatments of the uppers 21, the other parts of the footwear which must be assembled in the successive working phases, as for example, reinforcements, inner-soles, soles, heels and similar parts, normally remain in the trays 3 and 4 which hence remain outside and above the ovens.
At the end of the treatment the half- shells 26 and 27 retract to their open position freeing the frame 14 from the grip of the doors 24 and 25.
At this point the entire trolley 1 may be transferred to the successive working station.
In the station downstream of the one corresponding to the above mentioned treatment the operator finds all the uppers and the relative moulds 21 still inserted in the brackets 20 of the frame 14 and all the parts to be assembled on the upper trays 3 and 4.
Continuation of the operations occurs in this way without any loss of time.
The trolley 1 advances and passes the successive stations where the parts of the footwear are progressively assembled until complete assembly is achieved in the station up-stream of the one where the ovens for the successive heat treatments are installed.
At the end of the assembly operation of the footwear the operator, instead of loading the footwear into ovens outside the assembly line, or of placing them on one of the trays 3 and 4 for transfer to the successive station, pre-arranges them inside the brackets 20.
The trolleys 1 loaded in this way with the footwear to be treated placed inside the brackets 20 and the remainder of the parts still to be assembled distributed in an orderly way on the trays 3 and 4, pass on to the successive station where the ovens 33 and 34 are located.
On reaching this station the frames 14 are once again aligned with the doors 24 and 25 of another oven.
For the sake of clarity a schematic plan view is illustrated in Figure 3 detailing a section of the assembly line during this phase.
Two ovens 33 and 34 placed next to one another during the working phase, i.e. closed, are illustrated on the said sections of the assembly line.
Two trolleys 1 are arranged in correspondence to each oven. This arrangement and construction of the ovens makes it possible to half the execution times of the treatment.
The two separate ovens 33 and 34 are pre-arranged to perform the humidification and the hot air heating and the seasoning, the stretching under vacuum and radiation using infra-red ray heater treatments respectively. These ovens are not described in detail since they form a part of the technical note.
The automatic introduction of the footwear to be treated inside the said ovens, the seal forming closure of the doors 24 and 25 are entirely similar to those already described for the humidification treatment.
The carding and adhesive spreading phases are performed in the footwear production cycle in succession to the above mentioned treatments.
The rest phase then follows, presently requiring approximately twenty minutes, during which the solvents in the adhesives are completely evacuated, before re-activating the said adhesives and carrying out the application phases of the soles, the heels and of the other possible components. The time required for the said rest phase, represents another forced hold-up point of the assembly line process and results in forced speed limits or the engagement of a long section of the assembly line. According to the present invention, this period of time may be significantly decreased by the use of trolleys 1 with a vertical hanging frame 14 and of another opposite half- shell type oven 26 and 27, positioned downstream of the above mentioned adhesive spreading phase. The footwear 21 with adhesive covered bases and the corresponding soles, also spread with adhesive are placed on the brackets 20 of the support 14 and transferred inside an oven entirely similar to the one described previously.
This oven is equipped with heating means and means of forced suction under vacuum which permit a rapid and total evacuation of the solvents present in the adhesives, significantly reducing the time necessary for this phase. In particular conditions and with the use of several types of adhesives heating of the environment to avacuate the solvents makes it possible to re-activate the adhesive, necessary to make the relative parts adhere to one another in the phase successive to the exit from the oven.
Whereas, in other conditions and however thanks to the structure of the handing support 14, re-activation of the adhesives is performed outside the above mentioned evacuation oven, but however in sequence on the assembly line without having to unload and re-load the parts spread with adhesive into external ovens, as is the case at present. The heat sources, as for example halogen lamps, necessary to reactivate the adhesives spread over the bottoms, or over the soles, may be conveniently positioned inside the oven close to the surfaces of the soles and/or of the footwear bottoms thanks to the free surrounding space permitted by the structure of the frames 14.
One arrangement example of the heat sources 40 inside an oven to reactivate the adhesives is represented in Figure 4. In the solution illustrated and described, with particular reference to Figures 1 and 2, the hanging frame 14 has a fulcrum at the side edges 12 of the upper tray 3 and is pre-arranged to permit its guided oscillation and limited by the pins 16, bound on the side edges 15 of the lower tray 4 and inserted in the slits 17.
It is to be understood that the said solution is preferred in order to guarantee secure matching and a perfect seal between the parallel surfaces 28 and 29 of the hanging frame 14 and those 31 and 32 of the doors 24 and 25 when the half- shells 26 and 27 are moved together.
However, the possibility that the frame 14 may be bound vertically beneath the trays 3 and 4, in another way, independently from them is not excluded.
For example, by means of brackets directly bound to the supporting structure 2, as represented in Figure 4. Furthermore, the trolley 1 fitted with a vertical yoke type frame 14, may be equipped with only one, or more than two trays of the type 3 and 4 in its upper part depending on the working requirements, or may be without, as represented in Figures 5 and 6.
The structure described and illustrated above has proved to be the most rational and the most economic, in particular for application to footwear assembly lines.
In addition, its structure is such as to permit embodiment, even in pre-existing trolleys.
Other embodiment froms of trolleys with a yoke type frame 14 are represented in Figures 4, 5 and 6 applicable to other types of drawing chains, or for other types of use.
In particular, inside the frame 14, instead of the brackets, 20 different over-lying trays 41 may be applied (see Figures 5 and 6).
Another solution may include only the cross-pieces 19 or however other support means which however are contained within the profile of the frame 14.
Another possible embodiment, particularly suitable for the treatment .of many pieces, may foresee the frame support 14 with more than one drawing trolley; the fundamental concept remaining that the profile of the hanging frame must always form the ledge for the closing doors of the half- shells 26 and 27 making up the said ovens.
The hanging yoke type frame 14, though being preferably made up of a peripheric profile having a parallelogram shape to exploit the space enclosed by it in the best and most rational way, may be realised in accordance with any other shape, for example, circular, elliptic, trapezoidal, and so on. In any case, it is essential that its side surfaces 28 and 29 are substantially parallel and have a peripheric profile equal to that of the doors 24 and 25 of the half- shells 26 and 27 of each oven.
While the present invention has been illustrated and described in several of its preferred embodiments it is obvious to experts of the field that various changes to the form and to particulars may be made without by so doing leaving its protective context.

Claims

1. Assembly line, particularly suited for the production of leather and similar goods, comprising a plurality of transporter trolleys (1) travelling on rails (7) for transporting the goods in manufacturing plant through a multiplicity of working operations, and fitted with automatic coupling and release devices, and oven (33, 34) for humidification, heating, seasoning, stretching under vacuum, evacuation of vapours and radiation, wherein the ovens are arranged beneath the assembly line and in sequential series with the working stations and each transporter trolley is fitted with a vertical support frame (14), hanging and yoke type and it is straddled by ovens, characterized in that each oven (33, 34) is made up of two sliding half-shells (26, 27) which are arranged on opposite sides of the assembly line and are moved away and towards the support frame (14), the doors (24, 25) of the half-shells (26, 27) have a peripheric profile equal to that of the support frames (14), and the two side surfaces (28, 29) of the support frame (14) are parallel to one another and parallel to the surfaces (31, 32) of the oven doors (24, 25); the seal between the surfaces of the oven doors and the said side surfaces of the frame being ensured by gaskets (35) applied to the sides and to the surfaces (31, 32) of the doors (24, 25).

2. Assembly. line according to claim 1, wherein the two half-shells (26, 27) of each oven (33, 34) travel on transverse guides (30) by means of hydraulic, or pneumatic cylinders.

3. Assembly line according to claim 1 or 2, wherein each transporter trolley (1) is fitted with two supporting shelves or trays (3, 4) and the support frame (14) is fulcred or hinged to the edges of the upper tray (3) and is equipped with a transverse slit (17), in which a pin (16) is inserted fixed to the edges of the lower tray (4).

4. Assembly line according to claim 1 or 2, wherein the vertical support frame (14) is fulcred or hinged to brackets bound to the load bearing structure (2) of the trolley.

5. Assembly line according to any one of the previous claims, wherein the vertical support frame (14) is fitted with cross-pieces (19) sustaining the brackets (20) or the support hooks of the footwear (21) or of overlying trays (41).

6. Assembly line according to claim 3, wherein the trays (3, 4) are fitted with separators (10).

7. Assembly line according to any one of the preceding claims, wherein the oven (33, 34) is provided with heating means and means of forced suction under vacuum for the evacuation of the solvents of the adhesives.

8. Assembly line according to any one of the previous claims from 1 to 6, wherein a separate oven (33,34) arranged in sequence is provided for the reactivation of the adhesive, said oven being provided with heating means (40) close to the surfaces of the soles or of the footwear bottoms.