EP0711211B1

EP0711211B1 - Punching method for production of tubular pieces

Info

Publication number: EP0711211B1
Application number: EP94923047A
Authority: EP
Inventors: Bruno Candusso
Original assignee: Strato Srl
Current assignee: Strato Srl
Priority date: 1993-07-28
Filing date: 1994-07-21
Publication date: 1997-09-24
Anticipated expiration: 2014-07-21
Also published as: ITTS930004A0; EP0711211A1; DE69405874T2; ES2109006T3; ITTS930004A1; WO1995003900A1; DE69405874D1; ATE158523T1; AU7274994A; IT1265973B1

Abstract

The process is suitable for application in the sector of window and door frames, and in particular is relevant to the production of metal or plastic grills to fix onto windows, doors or items of fixtures and furnishings. It consists basically of two phases: cutting of the pieces of tubing to be used in the grill (3), single punching of the ends of each tubular element (1.1) to be used to form the junction (2) of the grill (3) itself. In this way, it is possible to avoid milling of the piece ends. In view of the punching, the working takes less time than processes employed today. It is also of advantage that the punching can be applied in the production in the tubing elements (1.2) of the openings (9) that have to take the joining bars (12) or arms of other types of internal junction.

Description

Technical Field

The present process is suitable for use in the sector of door and window frames, and in particular the area related to the production of metallic or plastic grills fitted to them.

Background Art

Metallic or plastic grills positioned between two glass sheets are in increasing use today in the sector of door and window frames. Their purpose is almost exclusively aesthetic, as opposed to former times when they were employed in the construction of stained glass windows (using lead) or for protection against theft.
Aluminium and light alloys are generally preferred today, though they are unable to guarantee complete protection against the break-in of intruders.
However, the lightness of these materials allows grills of modest weight to be constructed, which therefore do not weigh down the frames. The same also holds true for grills made in PVC or other plastic materials.
They may be fixed onto windows or doors, even where there is no glass compartment. The grills can additionally be used in all sectors of fixtures and fittings: furniture, mirrors, surfaces of room dividers, etc.
The grills are made up of tubular elements, put together into a solid construction through construction through internal and external forked connections at the junctions. These junctions are made up of arms at all possible angles, but the preferred forms are the right-angled cross, "X", "T", "L", "Y", and curved.
In this way, square, triangular, circular, and other geometrical shapes of varying degree of regularity can be built up, although without doubt the right-angled variety is most common.
More recently, union of the separate parts of the junctions has been carried out using a metal or plastic bar inserted across through openings made in one of the pieces, its free ends inserted into two other pieces, so that it also functions as a support for the structure.
A particular type of joint is described in DE-U-8900359, in which the pieces are joined by a linking element inside them; this element is widened by means of a screw.
The tubular elements employed have various profiles, though the form preferred by the market is a somewhat compressed hexagonal shape; this form is easier for introduction between the two glass sheets and in any case ensures minimum bulkiness on the windows and doors or fixtures and fitting. For this reason, bar or rod elements are sometimes used in grills, with very modest cross-section.
One of the main problems associated with the grills is that many pieces of the tubular elements (or rods or bars) are needed in the construction.
The manufacture of these elements is today rather costly because in order to provide for their perfect matching at the junctions, the elements themselves have first to be cut orthogonally and then a subsequent milling of the ends is applied until the various tube profiles meet perfectly together without leaving ugly gaps. Where the elements are joined using internal bars, it is essential to put in a series of holes (later milled), to allow insertion of the bars themselves.
Each of these operations in itself may be fairly low in cost, but they are repeated such a high number of times that production of the grill itself is a very expensive process. Just to give an example, it is sufficient to consider a simple grill made up of three vertical and three horizontal elements, comprising fifteen pieces, needing fifteen orthogonal cuts, eighteen milling operations of the ends to be inserted, nine holes for inserting the bars used in the junctions, and the same number of millings of these holes.
As far as technical skills today go, there is no alternative way of producing profiled tubular elements for the joints needed for making up plastic or metallic grills for doors and windows. In other sectors systems of metallic tube punching are known; examples of these production methods may be seen in USA Patent No. 3074302 and Canadian Patent No. 1179249. The above-mentioned USA Patent describes the preparation of an angle joint of a tubular quadrilateral member. The tube to be sheared is mounted in the recessed end of the female die with its end overlying the above end, limiting the part of the tube that protudes on the end. The male die is mounted inside the said tube and above said opening; one of the horizontal walls of the tube is punched from the inside so as to form a slot having axially extending sides substantially normal to the horizontal walls. This tube is played in a second recessed female die a second male die is selected and passed through the slotted portion of the tube towards the opposite portion of said tube.
The Canadian Patent describes a punching system for the production of tubular members used in scaffolding. The shearing apparatus cuts recesses at one end of the tubular member, acting from the interior towards the exterior. Said apparatus is constructed and fitted in such a way that the second support allows a pivotable displacement relative to the tubular member and the second die member is carried by said second support and effects a sheer on the tubular element upon bodily displacement of the second support in predetermined radially outward directions.

Disclosure of Invention

The purpose of this invention is to make available a process able to allow manufacture of pieces of tubular elements profiled in a suitable way for the construction of grills at a very modest cost, using simple methodologies and low operating costs.
Another aim is to allow production of pieces perfectly profiled for insertion into the junctions, more quickly than using current methods.
A final aim of this process is to work a number of pieces together.
These and other goals are brought together in the processing through punching of the tubular elements, as described herein, process that includes the cutting of the profiled pieces and their subsequent punching, such an to allow in a few simple operations the production of tubular pieces already profiled for inserting into the junction; a second punching then allows production in unbroken pieces of the necessary openings for inserting the bars or other pieces that form the junction.
This procedure of working can be applied in the production of pieces with a junction that is either orthogonal (cross, "T", "L", etc.) or angled at various degrees ("X", "Y", curved, etc.).
The advantage is thus gained of avoiding the operation of milling the piece ends.

Brief Description of Drawings

Further features and advantages of the working method can be seen better from a description of one of the preferred though not exclusive forms of carrying out the production of the piece, seen in the attached diagrams that give just one illustrative idea, where:

figure 1 shows a grill inserted within a glass compartment;
figure 2 gives greater detail of the axonometry of a junction where the tubular pieces are pulled out and the internal bar within the junction can be seen;
figure 3 shows in axonometry the junction from the previous figure, where the components have been brought together in a cross junction (at right angles);
figure 4 shows a front elevation of the pieces being worked in the punching process and of three tubular pieces;
figures 5, 6 and 7 also show sections of the punching press, along planes A-A, B-B and C-C of figure 4, together with the separated parts of the different punchings; the dotted linen indicate the movement of the various punches.

Mode for Carrying Out the Invention

To form a junction 2 of a grill 3 with cross-fitting (figures 1, 2 and 3) it is necessary to have two pieces of tubular elements 1.1 and one unbroken tubular element 1.2. The pieces of tubular elements 1.1 will make up the horizontal pieces of junction 2, while unbroken element 1.2 will be placed in a vertical position (for the mounting).
The procedure presented in the present invention includes, for the production of the two pieces of tubular elements 1.1. and the unbroken tubular element 1.2 necessary for each junction 2, the following sequence of four operations: a) orthogonal cutting of the pieces of tubular elements 1.1 and the unbroken tubular element 1.2, b) partial punching of the ends of the piece elements 1.1, c) full punching of these ends, d) lateral punching of the remaining unbroken tubular element 1.2.
In more detail, all tubular elements 1 are first cut orthogonal, to the required lengths, and then inserted into a pneumatic punching press.
This executes a punching of the ends that are to fit into the junction of each tubular element 1.1, removing the corner 4 from the worked piece, as seen in figure 5. This is done using punch 5 that begins its movement from the interior of element 1.1 being worked is obtained.
The third phase always occurs within the punching press; in the and of each tubular element 1.1 that was given a partial profiling during the previous operation, a second punching takes place, this time complete and acting on the whole profile, using punch 6.
This latter works orthogonally penetrating piece elements 1.1 through the opening left open by the removal of the first corner 4, removes a second corner 7 from tubular piece elements 1.1 and files down the whole of the inside of the end of this latter, removing two shavings 8 from the lateral works of tubular piece element 1.1.
This latter operation then allows production of tubular piece elements 1.1 with and outline perfectly profiled and ready for fitting straight into the junctions with tubular element 1.2 at junction 2 of grill 3.
The fourth and final phase always occurs within the same punching press. The unbroken tubular element 1.2 that is to constitute one of the mounting pieces of the grill undergoes a punching operation for creating slots 9 designed to allow the insertion of joining bar 12; said punching is performed by a punch 10 that works across through the two parallel walls of unbroken tubular element 1.2 itself, removing two surface pieces 11, of similar shape to the punch and of sufficient dimension to allow the passage of joining bar 12.
The last three phases are worked simultaneously, though on two tubular piece elements 1.1 and on one continuous tubular alement. 1.2.
The two tubular piece elements 1.1 and unbroken element 1.2 are then taken out from the punching press. A new tubular piece element 1.1 is positioned on the first matrix for removal of a first corner 4, a tubular piece element 1.1 already partly profiled is transferred to the second matrix for the punching of its whole profile and the removal of a second corner 7; a new unbroken tubular element 1.2 is placed on the third matrix, and so on.
All that remains at this point is to mount the grill 3. This is done by feeding bar 12 orthogonally through slots 9 of the unbroken tubular profile 1.2, such that its ends remain free; tubular piece elements 1.1 are then fitted onto these ends so forming the crossed junction 2.
In the example given above, a simple grill with three vertical and three horizontal components, made up of a total of fifteen elements, requires a total of fifteen orthogonal cuts, eighteen partial punching: of the ends of the pieces of tubular element 1.1, eighteen total punchings of the end of said pieces and nine for making the slots 9 on the unbroken tubular elements 1.2 for insertion of the bars 12 that are used to form the junction, giving a total of forty five punchings.
The total number of mechanical operations carried out is therefore greater than that in a traditional system but the speed is considerably higher for two reasons: higher speed of punching compared with milling and the simultaneous working of three different types of punching, that produce in a single operation one finished tubular piece element 1.1 and one finished unbroken tubular element 1.2.
The process of working, carried out in this way, can be modified or varied in many ways, all in line with the intentions of the original invention. In addition, all aspects may be replaced by others that are technically equivalent.
Of these variations, the most important points is that the profiling itself of the tubular piece elements 1.1 that make up the horizontal pieces of junction 2 can be accomplished in one single punching.

Claims

Method of producing tubular elements by punching, for the purpose of constructing metallic or plastic grills for insertion into compartments between glass sheets and in windows and doors and fixtures and fitting in general, where tubular piece elements (1.1) are joined to unbroken tubular elements (1.2), used for mounting, through internal or external junctions bar-type (12), cross-form, "X", "Y", curved, etc. and in which, use is made, where these joints are internal, of slots (9) in the unbroken tubular elements (1.2) and the ends of the piece elements (1.1) into which the junction bar-typs are inserted, that features a sequence of phases as follows:
- cutting of the tubular piece elements (1.1) and of unbroken tubular element (1.2) to be used in the grill (3), to required length;

- initial punching of the ends of one tubular piece element (1.1) with removal of a first corner (4) of any dimension using a first punch (5);

- a second punching of the ends of the same tubular piece element (1.1) with removal of a second corner (7) opposite the first corner of the same end and finishing of the whole internal profile, obtained by the passage of the relevant second punch (6) through the opening left by the removal of the first corner (4) at the first punching;

- punching of the two parallel side walls of unbroken tubular element (1.2) in order to obtain, through removal of surface pieces (11) in a single operation, slots (9) for housing the junction bar-typs (12); the initial and second punching may be replaced by a single punching of the ends of each tubular piece element (1.1) to be used in the fixing of junction (2) of the grill (3).
Punching method for production of tubular elements, in accordance with claim 1, characterised by the fact that the punching operation may be carried out with punches (5 and 6) of any shape and cutting plane, provided that they allow the required cutting of the corners (4 and 7) and that the punching press used can be actioned with any type of force: pneumatic, mechanical, manual, etc.
Punching method for production of tubular elements, in accordance with claims 1 and 2, characterised by the fact that the various types of punching on a number of tubular piece elements (1.1) and unbroken tubular elements (1.2) may also be carried out simultaneously in the same punching press.
Punching method for production of tubular elements, in accordance with claim 1, with the feature that it can be applied to grills made up of rods or bars.