Method and apparatus for changing spacers

A method and apparatus for the, preferably automated, changing of spacers in a plant having at least one applicator head for applying spacers to panel-shaped workpieces, in particular glass panes. Spacers from at least two sources are fed to the applicator head in an offset manner with respect to one another. A first spacer from a first source is separated. The resulting end of the first spacer and a start of the second spacer, which comes from a second source, are moved into a mutually assigned position by a changing device. Then, the end of the first spacer is connected to the start of the second spacer. A resulting connection of the first spacer with the second spacer runs through the plant until the connection has passed the applicator head. Thereafter, the second spacer is separated in a region between the connection and the applicator head.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to a method for changing spacers in a unit with at least one applicator head for application of spacers to sheet-shaped workpieces, especially panes of glass.

The invention furthermore relates to an apparatus for changing spacers in a unit with at least one applicator head for application of spacers to sheet-shaped workpieces, especially panes of glass.

Description of the Related Art

Spacers that are applied to sheet-shaped workpieces are used in particular in the production of insulating glass. In this case, the workpieces are panes of glass.

In addition to spacers that consist of metal sections, plastic spacers are also known that are flexible and that are applied to panes of glass using applicator devices.

If the formats of the sheet-shaped workpieces, for example the type of insulating glass, change, the problem arises that it becomes necessary to change from one type of spacer to another type. Here, a change is generally defined as the change between spacers of a different type and/or from different sources. Here, it can be, for example, spacers of the same type but with different width, spacers of the same thickness of different type or else completely identical spacers that are withdrawn from different (supply) spools, for example if the spacer from one (supply) spool is coming to the end.

In doing so, it should be avoided that spacers from different sources are applied to the same workpiece, since even for identical spacers, the junction (connection) between the spacers constitutes a potential leakage site; this is disadvantageous in, for example, insulating glass.

In the past, a change of spacers required many steps to be carried out by hand, for example the removal of the existing spacer and the “threading” of the new spacer into the unit. This is mainly very personnel-intensive and time-consuming.

BRIEF SUMMARY OF THE INVENTION

The object of the invention is to devise a method and an apparatus for changing spacers that allow changing of spacers that is efficient in terms of time and money.

The object is achieved according to the invention with a method.

The invention is also implemented with a device.

Preferred and advantageous configurations of the method and of the apparatus according to the invention are the subject matter of the dependent claims.

One advantage of the invention is that the changing of spacers can take place partially or completely automatically.

Spacers from at least two different sources are supplied to the applicator head staggered in time to one another. In this case, the different sources can be both different (supply) spools, for example in one climate-controlled cabinet, and also in several climate-controlled cabinets, or the like. The climate-controlled cabinets are used to maintain conditions that are especially favorable for spacers. Their operation and their structure are known from the state of the art.

For changing spacers, first of all the first or “old” spacer that is currently located in the unit or in the applicator head and that is removed from a first source is severed near the first source. In doing so, one end of the first spacer is formed. The latter can preferably be held by a holder that is intended for this purpose. A start of a second or “new” spacer is located in the vicinity of the end of the first spacer. The start of the second spacer can likewise be held by a holder that is intended for this purpose. The start of the second spacer and the end of the first spacer are then caused to approach one another, for example by the holders approaching one another, preferably until the start and end at least touch. Then, a connection is established between the end of the spacers and the start of the spacers. This can take place preferably by cementing, pressing, clamping or similar methods.

If the first spacer continues to be conveyed, the resulting connection between the first and the second spacer passes through the unit until the connection has passed the applicator head. The first (old) spacer therefore continues to move through the unit and in doing so entrains the second (new) spacer via the connection through the unit. This thus eliminates time-consuming threading of the second (new) spacer.

After the connection between the first and the second spacer has passed the applicator head, the second spacer is severed in a region between the connection and the applicator head. Subsequently, the second (new) spacer is in the applicator head, and the region of the connection has been removed from the production and application process.

Especially preferably, the first spacer is severed after a first removal unit that removes the first spacer of the first source. The removal unit comprises devices that are necessary for the removal of a spacer from the source. The removal unit can withdraw the spacer from, for example, a (supply) spool and prepare it for further use by, for example, a protective film being removed from the spacer. The removal unit can also contain still further elements that are known from the state of the art.

In another preferred embodiment of the method, the second spacer is severed after the connection between the first and second spacers has emerged from the applicator head on the delivery side. Thus, the applicator head after severing is again ready to apply the second (new) spacer to a workpiece. Especially preferably, when the second spacer is severed, the distance between the connection and the applicator head is kept as small as possible. Thus, less scrap is formed.

According to one quite especially preferred embodiment of the method of the invention, when different spacers are to be applied to two successive workpieces, the required length of the first spacer that is to be applied is computed based on the dimensions of the first workpiece (more than only one workpiece can also be taken into account) and the first spacer is severed on or after the computed end and is connected to the second spacer. This avoids an uneconomically large amount of the first spacer from passing through the unit only in order to draw the second spacer through the unit. Thus, changing the spacers is undertaken with regard to the future. Thus, only one short piece of first and second spacers at a time arises upstream and downstream from the connection, which spacers cannot be used.

Therefore, in the invention, it is possible to carry out the changing of spacers at any time. The time is, however, preferably chosen such that scrap (and thus residues to be disposed of) is formed to the smallest degree possible.

Within the scope of the invention, the use of spacers that consist of plastic and are flexible and into which a desiccant is embedded is considered.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The unit that is shown schematically inFIG. 1, aside from the details described below, can be designed as is known from the state of the art.

FIG. 1shows a unit for applying spacers with an apparatus according to the invention. A first spacer1and a second spacer2are held in readiness on (supply) spools3and4in a climate-controlled cabinet5.

The climate-controlled cabinet5is made as is known from the state of the art and maintains ambient conditions that are favorable for the further processing of the spacers1and2, such as, for example, temperature and/or atmospheric humidity. The apparatus according to the invention can have several climate-controlled cabinets.

The spacers1and2travel from the climate-controlled cabinet5into a removal device6. The removal device6that is connected downstream from the climate-controlled cabinet5can contain, among others, an arrangement for suction of protective films off spacers1and2that generally consist of elastic plastic, a sag control for uniform removal of the spacers1and2, and devices for removing and conveying the spacers1and2in each case (not shown).

In addition to the indicated elements, the removal device6has removal-clamping devices7and8with which the spacers1and2can be held in a defined position. Aside from the aforementioned changes, the removal device6can be made as is known from the state of the art.

In the illustrated embodiment, spacers1and2are removed via the same removal device6. Embodiments with more than one removal device6are likewise considered within the scope of the invention.

On the delivery side of the removal device6, there is a separating means9, with which the spacers1and2can be severed. The illustrated embodiment shows the first spacer1in severed form. The end13of the first spacer1that is assigned to an applicator head12is held in a changing-clamping device10. The other end of the first spacer1, which end is located in the removal device6, is held by the first removal-clamping device7.

The end13of the first spacer1can be moved with the changing-clamping device10to a start14of the second spacer2, which is held by the removal-clamping device8, as is indicated by an arrow15. After the end13(as indicated by the broken line) has been brought into the vicinity of the start14, the start14and end13are connected to one another using an apparatus16to form a connection11. The apparatus16for joining can join the start14and the end13to one another, for example by cementing, pressing and/or clamping.

By way of example,FIG. 2shows one embodiment of the connection11between the first spacer1and the second spacer2by means of a clamp17.

After the connection11has been established, the spacers1and2pass in succession through a feed18that supplies the spacers1and2to the applicator head12.

In the illustrated embodiment, the feed18has a dancer roll19. Such an embodiment is advantageous even if during the changing and joining of spacers1and2, the application of spacers is not to be interrupted. While the removal is interrupted for the changing from spacer1to spacer2, in the continued application a length of the spacer1and2that is stored by way of the dancer roll19in the feed18is used up. Embodiments in which there are no dancer rolls19or the like, such as, for example, another sag control, are likewise conceivable. Thus, for example, the application can be interrupted during the changing from spacer1to spacer2.

The spacers1and2travel from the feed18in succession into the applicator head12. The latter applies the spacers1or2to the workpiece22,23, for example a pane of glass that is conveyed via a conveyor apparatus24into the applicator unit and again out of the latter. After application, another separating means20separates the applied spacer1or2from the spacer1or2that is still located in the applicator head12. This separation takes place preferably immediately after the applicator head12.

Altogether, the manner of operation according to the invention in an exemplary process sequence (FIG. 3) can be summarized as follows:

Using an applicator head12, a flexible spacer1or2(also called “spacer”) is applied to a workpiece22,23, such as, for example, a pane of glass, which is located in an applicator unit, along the edge of the workpiece22,23(offset to the inside relative to the edge).

In each case, the one of the spacers1and2that is already located at the exit end of the applicator head12is severed for completion of an application of the spacer1or2to a workpiece22,23so that a new, free end of the spacer1or2is ready for the application.

The inventive changing from the first spacer1to the second spacer2takes place as in the steps 1 to 10 that are indicated below.

While these steps are being executed, the application process can be interrupted. It is also possible, however, to store in the unit enough spacers1and2for the time that is necessary for changing, for example by way of a dancer roll19, and only to interrupt the removal of spacers1and2from a storage unit, for example a supply spool3,4.

This can take place in any phase of spacer application. The instant at which the changing from the first spacer1to the second spacer2is carried out is preferably chosen using future-oriented production planning such that as little scrap (spacer residue) as possible forms. The instant of changing is preferably chosen such that the spacer1or2that is located at this instant in the spacer feed18between the applicator head12and removal device6is used as completely as possible, and therefore can be applied to a workpiece22,23in order to minimize the amount of scrap that forms. The spacer feed18between the applicator head12and the removal device6picks up a spacer strand of a length that corresponds to, for example, the circumference of a workpiece or a few workpieces, such as panes of glass.

Generally, the length of the spacer1or2that is located in the spacer feed18does not correspond to an integral multiple of the circumference of the workpiece22,23, for example panes of glass, plus the length of a comparatively short piece of scrap, so that the changing takes place in most cases at an instant at which the application of spacers1and2to a workpiece22,23takes place and not at an instant at which the application of the spacers1and2to a workpiece22,23is already completed and the application of spacers1and2to a workpiece to be processed subsequently has not yet been started. If a dancer roll19stores an additional length of spacer1or2in the unit or the feed18, the latter is also included in computations for optimization of the length.

Changing from a first spacer1to a second spacer2can take place in the following steps:

Step 1: In the removal device6, spacers1and2are prepared by their being held in a defined position by removal-clamping devices7and8.

Step 2: The first spacer1that is in use at the start of changing (old spacer) is separated on the exit side end of the removal device6by the separating means9, for example separating shears provided on the changing unit, being actuated. The changing-clamping device10retains the feed-side end13of the first spacer1, which end is formed after severing.

Step 3: The free ends13and14of the spacers1and2that are to be joined to one another are caused to approach one another by the changing-clamping device10with the end13of the first spacer1being moved toward the second removal-clamping device8, which holds the start14of the second spacer2.

Step 4: The end13of the first spacer1and the start14of the second spacer2are pressed onto one another, and using a joining device16, for example using a clamp17, they are joined to one another and thus the connection11is produced.

Step 6: Using a drive that is provided in, for example, the applicator head12, the first spacer1is moved forward and in doing so entrains the second spacer2that is now joined to it.

Step 7: The separating process in the first spacer1that ends the application of the first spacer1to the workpiece22,23(the old spacer1is applied to the latter) is undertaken such that the separation site, relative to the feed direction of the spacers1and2, is upstream from the joining site11.

Step 8: The connection11between the first (old) spacer1and second (new) spacer2is conveyed by the applicator head12.

Step 9: Relative to the feed direction of the spacers1and2, downstream from the connection11on the exit end of the applicator head12, a separating cut is made so that a new, free start of the second (new) spacer2is ready for application to a workpiece22,23, for example a pane of glass, for example when insulating glass is being produced.

Step 10: The piece of scrap that bears the connection11, therefore the piece that contains the old and new spacers1and2between the separating cut after step 7 and the separating cut after step 9, is ejected.

In summary, one embodiment of the invention can be described as follows:

In a method and a device for preferably automated changing of spacers1,2in a unit with at least one applicator head12for application of spacers1,2to sheet-shaped workpieces22,23, especially panes of glass, spacers1,2from at least two sources are supplied to the applicator head12, staggered in time to one another. A first spacer1from a first source is severed. The resulting end13of the first spacer1and a start14of the second spacer2that comes from a second source are moved with a changing apparatus into a position assigned to one another. Then, the end13of the first spacer1is joined to the start14of the second spacer2. A resulting connection11of the first spacer1to the second spacer2runs through the unit until the connection11has passed the applicator head12. After the connection11has passed the applicator head12, the second spacer2is severed in a region between the connection11and the applicator head12.