EP2204460B1 - Method and device for heating workpieces - Google Patents

Description

The invention relates to a method for treating workpieces, in which the workpieces are heated in a furnace in a plurality of horizontal furnace levels, wherein the furnace levels are arranged vertically one above the other and each furnace level is in each case at a certain height. In this case, each furnace level is designed to accommodate at least one workpiece, and the workpieces are removed after heating in a defined order from the oven levels.

The invention further relates to a device or a furnace for carrying out this method.

The important goals of the automotive industry today and in the future include the reduction of fuel consumption, the reduction of CO ₂ emissions and the increase in occupant safety. A common means of reducing fuel consumption and thus reducing CO ₂ emissions is, for example, the reduction of vehicle weight. However, at the same time to achieve an increase in occupant safety, the body panels used must have higher strength at a lower weight.

There is therefore a growing interest in body steels with a favorable strength to weight ratio. This is usually achieved by the process of so-called press-hardening or also form-hardening. In this case, a sheet metal part is heated to about 800 ° C to 1004 ° C and then deformed in a cooled tool and quenched. The strength of the component thereby increases up to about three times. Press hardening makes construction easier and still rigid body components through the combination of heat treatment, shaping and simultaneous controlled cooling.

For the heat treatment of body steels different furnace concepts have been developed in the past. In particular, the principle of the continuous furnace has found widespread use in press hardening. In this furnace principle to be heated body steels are transported on workpiece carriers via conveyors through the oven. As a conveyor rollers, chains or belts are used, with conveyors can be provided in several oven levels.

However, continuous ovens usually have the disadvantage that they have a large amount of space due to their length expansion. In order to save space, it is therefore also possible alternatively to use ovens with a plurality of oven levels arranged one above the other horizontally, which are also referred to as stack ovens. The individual oven levels can be provided with drawer elements which are pulled horizontally out of the oven for loading and unloading of workpieces. The loading and the removal of workpieces from the individual stacked oven levels is preferably carried out via a height-traversable loading and unloading device.

For the subsequent transport of the heated workpieces of such a multi-deck oven for subsequent shaping a certain time is required. During this time, a cooling of the workpieces, while they are moved by the ambient air. Due to the differences in height of the individual oven levels of the bunk oven, the times for the transport of the individual workpieces differ. These different times result in different high temperature losses for the workpieces. These different temperature losses in turn can lead to differences in the quality of the body parts to be manufactured.

The US patent US Pat. No. 6,227,848 B1 discloses a method of treating workpieces having the workpieces in a furnace in a plurality of horizontal Oven levels are heated. The oven levels are vertically stacked, with each oven level at a height. Each furnace level is designed to receive a workpiece. The workpieces are removed after heating in a defined order from the oven levels. For this, the oven levels are moved stepwise vertically, so that the respective heights of the individual oven levels change. The oven levels are moved vertically in a stepwise manner so that the height of the respective oven level, from which a workpiece is removed, corresponds to a fixed removal height and the respective oven level is at the removal level for a certain period of time. However, the removal is difficult depending on the geometry of the workpieces, whereby different periods of time can be required when gripping.

The German patent DE 10 2006 020781 B3 discloses a furnace for heating steel blanks having a plurality of horizontally stacked furnace planes, each furnace plane being provided for receiving at least one steel blank, and means being provided in each furnace plane for moving the steel blanks during heating.

The German patent application DE 199 48 606 A1 discloses a method for tempering components, e.g. As semiconductor circuits, printed circuit boards and the like, in which the components are conveyed on carriers through an entrance slot in a tempering provided with Temperierorganen and discharged through an entrance slot opposite the exit slot. The carriers are received in the housing by a magazine which is provided with adjacently arranged holders and, after loading the first holder, is successively shifted in a direction from a starting position to successive receiving positions in which the individual holders of the magazine are successively fed. After loading all the holder is then the magazine so filled from the final position reached in the opposite direction in fast return to its original position moved back in the conveying a carrier through the entrance slot and filled magazine the conveying out of the first tempered in the magazine carrier through the exit slot and with the successive loading of the individual holders of the magazine, the successive conveying out of the individual tempered carrier takes place.

An object of the invention is therefore to provide a method by means of which workpieces, in particular body steels, can be heated to They then press-harden, without there being any major fluctuations in the quality of the finished body components.

The method should both keep the time of the transfer of the heated workpieces from the oven to the subsequent shape for each workpiece as constant as possible, as well as minimize the space required for the oven for heating the workpieces.

An object of the invention is also to provide an apparatus for carrying out such a method.

This object is achieved by a method having the features of independent claim 1. Advantageous developments of the method will become apparent from the dependent claims 2 to 7. The object is further achieved by a device according to claim 8. Advantageous embodiments of this device will become apparent from the subclaims 9 to 14.

The invention comprises a method for treating workpieces, in which the workpieces to be treated are heated in a furnace in a plurality of horizontal furnace planes (E ₁ ... E _n ), which are arranged vertically one above the other. Each furnace level (E ₁ ... E _n ) is in each case at a certain height (h ₁ ... h _n ) and can accommodate at least one workpiece to be heated. After heating, the workpieces are removed from the oven levels (E ₁ ... E _n ) in a defined sequence. For the removal of the heated workpieces, the oven levels (E ₁ ... E _n ) are moved stepwise vertically, thereby changing the respective heights (h ₁ ... h _n ) of the individual oven levels (E ₁ ... E _n ). The stepwise vertical movement takes place in such a way that the height (h ₁ ... H _n ) of the respective furnace plane (E ₁ ... E _n ), from which at least one heated workpiece is removed, corresponds to a defined removal height h _x and the respective furnace level (E ₁ ... E _n ) is at the extraction height h _x for a time t> 0.

In this case, the position of the oven levels (E ₁ ... E _n ) is fixed in relation to the furnace, and the furnace is heated for the removal Workpieces from the oven levels (E ₁ ... E _n ) are moved stepwise vertically by adjusting means. One embodiment of the method uses a lifting system as adjusting means, while another embodiment uses a pulling system.

The heated workpieces are removed in a development of the method by means of a transfer device on the removal height h _x from the respective furnace levels (E ₁ ... E _n ). The removal takes place in such a way that the transfer _device picks up the workpieces at the defined removal height h _x and at least partially removes them horizontally. For example, the workpieces are removed horizontally at the defined removal height h _x .

In a further development of the method, after the removal of a heated workpiece from one of the oven levels (E ₁ ... E _n ), a new workpiece to be treated is introduced into the same oven level (E ₁ ... E _n ). In a further embodiment of the method, the workpieces are introduced into drawer elements which are arranged on the individual oven levels. In this case, a drawer element on the removal height h _x horizontally moved out, removed a workpiece and then moved back the drawer element.

The invention further comprises a device for treating workpieces, comprising a furnace with a plurality of horizontal furnace levels (E ₁ ... E _n ), which are arranged vertically one above the other and in which workpieces are heated. Each furnace level (E ₁ ... E _n ) is located at a height (h ₁ ... h _n ) and is designed to receive and remove at least one workpiece. The device has adjusting means for stepwise vertical movement of the oven levels (E ₁ ... E _n ), which are designed such that they correspond to the respective heights (h ₁ ... H _n ) of the individual oven levels (E _{1 n} ) can change. The adjusting means can move the oven levels (E ₁ ... E _n ) in a stepwise vertical manner so that the Height (h ₁ ... h _n ) of a respective furnace level (E ₁ ... E _n ) corresponds to a fixed extraction height (h _x ) and that the respective furnace level (E ₁ ... E _n ) for a period t> 0 can be held at the removal height h _x .

In this case, the position of the oven levels (E ₁ ... E _n ) is fixed with respect to the oven, and the adjusting means are designed so that they can move the oven stepwise vertically. One embodiment comprises a lifting system as adjusting means, while another embodiment comprises a pulling system.

The device according to the invention preferably comprises a transfer device for removing heated workpieces from the oven levels (E ₁ ... E _n ) at the removal height h _x . This transfer device is also designed to charge the oven levels with workpieces to be heated. In this case, the transfer device has means to take the heated workpieces at the defined removal height h _x and remove them at least partially horizontally. For example, the transfer device may have means for transporting workpieces horizontally at the defined removal height h _x .

In a further development of the device, after the removal of a heated workpiece from one of the oven levels (E ₁ ... E _n ), the transfer device can introduce a new workpiece to be heated into the same oven level (E ₁ ... E _n ). In a further embodiment of the device, the oven levels (E ₁ ... E _n ) comprise drawer elements which are provided for receiving workpieces and can be moved horizontally on the removal height h _x .

The described method and the device for treating workpieces have the advantage that workpieces can be heated in a furnace with a reduced space requirement and can always be removed from the oven after heating at the same height. For this purpose, the oven comprises several oven levels (E ₁ ... E _n ), the targeted be changed in height (h ₁ ... h _n ) and so can be adapted to a fixed extraction height h _x . The respective height (h ₁ ... H _n ) of the oven levels (E ₁ ... E _n ) is thereby changed such that it corresponds in each case to the removal height h _x , so that workpieces from the oven levels are always removed at the removal height h _x and preferably also be charged. The required stepwise vertical movement of the oven levels (E ₁ ... E _n ) is made possible by the use of adjusting means.

The invention thus turns away from continuous furnaces in which the workpieces are moved successively through an oven for heating. It also turns away from height-adjustable removal devices, which are used in floor ovens for removing the heated workpieces use.

An advantage of the invention over conventional methods for preventing variations in quality in the manufacture of body components is always the same time for the transfer of workpieces from the oven for further shaping. Although a continuous furnace also offers this possibility, however, it has a corresponding length extension and an associated high space requirement.

The reason for this is the construction of a continuous furnace. In this furnace principle, the workpieces to be heated are transported in succession on workpiece carriers via conveyors horizontally on a furnace level through the oven. In addition to other parameters, both the heating time and the number of parts to be heated determine the required length of the continuous furnace. The longer it takes for the workpieces to reach the required heating temperature and the more workpieces to be heated, the greater the length expansion of the continuous furnace.

This large length extension of the continuous furnace would be compensated by the use of a stack oven. Since in this furnace principle, the individual furnace levels are vertically above each other, each workpiece is located for heating in a different height, which for removing the heated workpieces of a Removal device must be approached. From the different heights of the oven levels, a different transfer path from the oven to further shaping results for each oven level. However, the longer the transfer path, the longer it takes for the heated workpiece to reach the further shape and the greater the temperature loss of the heated workpiece. Large temperature losses can lead to large variations in the quality of the body parts to a failure of the parts.

The invention solves this problem advantageously by a height adjustment of the oven levels to a fixed extraction height h _x . Each furnace level is moved to this removal height h _x for removal of the heated workpiece and held there for a time t> 0 so that the transfer path from the furnace to further shaping is the same for each removed workpiece. This results in a comparable Temperaturvsrlust for each removed workpiece, which has reduced fluctuations in the quality of the body components result.

The above and other advantages, features and expedient developments of the invention will become apparent from the embodiments, which are described below with reference to the figures.

Fig. 1

eine schematische Darstellung eines höhenverstellbaren Ofens mit mehreren Ofenebenen zum Erwärmen von Werkstücken;

Fig. 2

eine schematische Darstellung eines Kugelgewindetriebes;

Fig. 3a

ein schematisches Ablaufdiagramm, welches den Ablauf bei der Bestückung eines Ofens wiedergibt;

Fig. 3b

ein schematisches Ablaufdiagramm, welches den Ablauf bei der wiederholten Bestückung und Entnahme von Werkstücken wiedergibt;

Fig. 3c

ein schematisches Ablaufdiagramm, weiches den Ablauf bei Beendigung der Erwärmung von Werkstücken wiedergibt;

Fig. 4

eine schematische Darstellung verschiedener Bestandteile einer Anlage zum Presshärten von Werkstücken; und

Fig. 5

eine schematische Darstellung einer Anlage zum Presshärten von Werkstücken mit zwei Öfen.

From the figures shows:

Fig. 1

a schematic representation of a height-adjustable oven with multiple furnace levels for heating workpieces;

Fig. 2

a schematic representation of a ball screw drive;

Fig. 3a

a schematic flow diagram representing the sequence in the equipping of a furnace;

Fig. 3b

a schematic flow diagram, which shows the sequence in the repeated assembly and removal of workpieces;

Fig. 3c

a schematic flow chart, which shows the process at the completion of the heating of workpieces;

Fig. 4

a schematic representation of various components of a plant for press hardening of workpieces; and

Fig. 5

a schematic representation of a plant for press hardening workpieces with two ovens.

In Fig. 1 schematically shows the example of a height-adjustable furnace 101 for heating workpieces, which typically includes a housing with an opening for the assembly and removal of the workpieces to be heated. The oven also comprises any number n of horizontal oven levels (E ₁ ... E _n ), on each of which at least one workpiece can be heated. The oven levels (E ₁ ... E _n ) are separated from each other and lie vertically one above the other. This in Fig. 1 Example shown shows seven oven levels.

Each of the oven levels (E ₁ ... E _n ) contains at least one receptacle for storage of the workpieces during heating. The design of the images is variable and depends, inter alia, for example, on the shape of the workpieces to be heated. The workpieces are in the receptacles during heating and are removed again after heating. The recordings are, for example, drawers 102, which can be extended and retracted via a horizontal movement 103. In Fig. 1 For example, the example of an extended drawer 104 is shown in which a workpiece 105 is located. For heating, the drawer is equipped with a workpiece 105, retracted for heating the workpiece 105 and then extended again.

Since the workpieces are not heated horizontally next to one another but vertically above one another, the size of the base surface of the furnace 101 can be minimized with such an oven principle. This leads to a reduction in the space required for the furnace 101. Furthermore, with this furnace principle, the size the surface of the furnace 101 are minimized, which in turn leads to a reduction of energy consumption by reduced surface losses.

The furnace 101 further comprises a lifting system with which the oven levels (E ₁ .. E _n ) can be moved by an up and down movement. At the in Fig. 1 By way of example, the height-adjustable oven 101 is shown as having the lifting system mounted on the bottom outside of the oven 101 so that the movement of the oven levels (E ₁ ... E _n ) is realized by movement of the entire oven 101. This has the particular advantage that the lifting system is not exposed to the prevailing in the furnace high temperatures T of up to 1000 ° C and thus need not have required for these temperatures temperature resistance. Another advantage is that the housing of the furnace 101 only needs to enclose the oven levels (E ₁ ... E _n ) with all the necessary accessories for heating workpieces 105. As a result, it is not necessary to heat additional volume within the furnace 101, which among other things leads to an optimization of the energy requirement of the furnace 101.

The lifting system is, for example, adjusting means 106, which can influence the height of the furnace 101 via a vertical movement 107. In Fig. 2 is shown as an example of an adjustment 106, a ball screw. Ball screws are helical gears for converting a rotational movement 201 into a translational movement 202. One component of the ball screw is a ball screw 203, which is driven by a motor 204 and carries out the rotational movement 201. The ball screw 203 consists of a ball screw rod 205 in the form of a cylindrical round rod on which a ball screw 206 is applied. On the ball screw 203 is a non-rotatably mounted spindle nut 207, which performs the translatory movement 202. Balls 208 pass through a recirculating ball 209 for ball return within the spindle nut 207.

By means of a ball screw very large forces can be applied. This is particularly advantageous in view of the high weight of the furnace 101, which must be moved at a height adjustment. In addition, the use of a ball screw because of its high mechanical efficiency of> 90% is particularly advantageous for the required cycle times from the assembly to the removal of the workpieces, which are in the range of about 10 seconds. Further advantages of the Kugeigewindetriebes are in particular in a low wear and associated high durability of the transmission, in a high positioning and repeatability and in high speeds, which can be implemented.

In one embodiment, the spindle nut 207 is driven by a motor 204 and thus moved with respect to the ball screw shaft 203. In this way, the spindle nut 207 carries out the rotary movement 201, while the non-rotatably mounted ball screw 203 controls the translational movement 202. In another embodiment, instead of the ball screw, a roller screw drive is used in which rollers are used instead of the balls 208, but they are also other adjustment 106 can be used.

Alternatively, any other suitable devices can be used as traction means. Another embodiment of the invention used for height adjustment of the furnace 101, for example, pulleys or chain hoists with lifting chains. In particular at locations with existing installations for traction means can result in corresponding cost savings. To reduce the drive power and thus the energy demand in traction means counterweights can be used, for example.

In another embodiment, push chains for height adjustment of the furnace 101 are used. Thrust chains are special chains, which stiffen in contrast to the known tension chains in the thrust direction, but over Sprockets remain deflectable. The ability to push is made possible by specially shaped chain links, which interlock positively and support each other with little play. Due to the geometry of the link plates buckling under pressure load by the weight of the furnace 101 is prevented. Push chains thus work like a conventional linear drive as a rigid telescopic drive rods. But they are extremely flexible when it comes to storage. The chains can be redirected to where there is room, and they can be wound up to save space. Advantages of push chains are in particular the implementation of uniform smooth movements of the oven levels (E ₁ ... E _n ) in the height adjustment, holding an absolute position for removal of the workpieces 105 and a compact storage possibility of the push chains.

The schematic sequence of a process for heating workpieces in a height-adjustable furnace show the FIGS. 3a-3c an example. There are Fig. 3a the steps in the assembly of the furnace up to a process point 1 again. Before starting the process, the furnace 101 is heated to a defined temperature T, which is usually 800 ° C to 1000 ° C during press hardening. After reaching the defined temperature T, a lifting system changes the height of the furnace 101 until the height h _{1 of} the furnace level E ₁ corresponds to a defined height h _x in which the furnace plane E ₁ then remains for a time t> 0.

A height h designates the distance of an object point from a reference line or reference surface. The distance between object point and reference line is preferably determined by the direct comparison of the distance to be determined with a scale. In this case, for example, serve as a reference line, the bottom surface on which the furnace is placed, so that the height h _x corresponds to a certain distance from the ground. The variable heights of the oven levels are adjusted to this height h _x by a vertical movement of the oven.

After the height adjustment of the furnace 101, the drawer 102 of the furnace level E _{1 is} extended, equipped with a workpiece to be heated 105 and then retracted again. It follows a renewed change in the amount of Furnace 101 by the lifting system, so that then the height h _{2 of} the furnace level E ₂ corresponds to the height h _x , in which then the furnace level E ₂ for a period t> 0 remains. After completion of height adjustment of the furnace 101, the drawer 102 of the furnace level E _{2 is} extended, equipped with a workpiece to be heated 105 and then retracted again. This process is repeated stepwise until the drawers 102 of all oven levels (E ₁ ... E _n ) are equipped by the oven levels are each moved to the defined height h _x .

The thus introduced into the height-adjustable furnace 101 workpieces 105 are heated in the oven within a defined residence time to a defined temperature T, which is exemplified for some body steels 860-980 ° C. If at least the first workpiece to be removed has reached the required temperature, the in Fig. 3a reached process point 1 reached.

If the heating of the workpieces 105 at process point 1 is completed, follows as in Fig. 3b reproduced, a repeated change in the height of the furnace 101 by the lifting system until the height h _{1 of} the furnace level E ₁ again corresponds to the height h _x , in which the furnace level E ₁ then again for a period t> 0 remains. The drawer 102 of the oven level E ₁ is extended and the heated workpiece 105 removed therefrom. If the entire process has not yet ended, the drawer 102 is again equipped with a workpiece to be heated 105 and then retracted again. There follows a further change in the height of the furnace 101, so that thereafter the height h _{2 of} the furnace level E ₂ corresponds to the height h _x , in which then the furnace level E ₂ remains for a time t> 0. The drawer 102 of the oven level E ₂ is extended, the heated workpiece 105 removed therefrom, the drawer 102 equipped with a workpiece to be heated 105 and then retracted again. This process is repeated stepwise until the drawers 102 of all oven level (E ₁ ... E _n ) are again equipped with workpieces 105 to be heated, which are then heated to the defined temperature T within the defined residence time.

The process of repetitively heating workpieces 105 in a height adjustable furnace 101 is terminated when the in Fig. 3b illustrated Process point 2 is reached and after a successful removal no further workpieces 105 are introduced for heating in the oven levels E _n . Thereafter, the furnace 101 may be cooled, for example. The steps in the last removal of heated workpieces from the individual oven levels are in Fig. 3c shown.

Within the process for heating workpieces 105, it is possible in a further development to equip the oven levels (E ₁ ... E _n ) with workpieces 105 in any desired and also varying order and / or to remove workpieces 105. This has the advantage that different workpieces 105, for example, workpieces 105 with different thickness, can be treated with different residence times in the furnace within a process, which is realized by a corresponding control of the furnace.

In one embodiment, it is also possible to equip all furnace levels (E ₁ ... E _n ) with workpieces 105, remove the workpieces after heating from the furnace levels (E ₁ to E _n ) and only when all workpieces the oven levels (E ₁ to E _n ) were removed, the oven levels (E ₁ to E _n ) to re-stocking. In another embodiment, not all oven levels (E ₁ to E _n ) are used to heat workpieces 105. This is particularly advantageous if only a few parts to be heated. Furthermore, it is possible to remove workpieces from the oven levels (E ₁ to E _n ) even in the event of incidents, even if the oven levels (E ₁ to E _n ) are not at the height h _x . These different embodiments can be realized in a control of the entire arrangement, which is freely programmable.

The workpieces 105 to be heated are, in particular, sheet metal parts made of body steel for press-hardened body components in automobile construction. However, other or non-formed workpieces of other materials may also be heated.

One embodiment provides for producing workpieces 105 with partially different properties, in particular for the aforementioned body components in the automotive industry are beneficial. For this purpose, a drawer 102 is partially moved out some time before the actual removal of the workpiece 105, so that the workpiece 105 partially cooled to a temperature below the austenite or hardening temperature and a subsequent press hardening in the already cooled part no very hard martensite, but a perlite Forms ferrite structure. This structure has significantly higher strain rates and is less susceptible to breakage in the event of a vehicle crash.

In the in Fig. 4 schematically illustrated example, the height-adjustable oven 101 is part of a system for press-hardening of workpieces. A workpiece 105 is removed after heating from the extended drawer 104 of a furnace level E _{1 of} the furnace 101 at a height h _i = h _x . The removal takes place for example by a transfer device 401, which is equipped with at least one gripper 402 for receiving and storing workpieces. Fig. 4 shows by way of example a transfer device 402 with four grippers. After removal of the heated workpiece 105, the transfer device 402 performs a movement 403 from the furnace 101 to a pressing tool 404 and transfers the workpiece to the pressing tool 404.

The pressing process can be carried out by methods and pressing tools that are well known to those skilled in the art. In the pressing tool 404, the workpiece 105 is deposited by the transfer device 402, and the transfer device 402 then returns from the pressing tool 404 to the furnace 101.

A development provides that the transfer device 401 is designed both for removing a workpiece 105 from a furnace level and for further transport to a pressing tool 404 and for loading a furnace level. To this end, the transfer device 401 picks up a workpiece to be heated on the way from the pressing tool 404 to the furnace 101, transports it to the furnace 101 and deposits it in one of the oven levels.

The height of the pressing tool 404, based on the floor of its location, for example, also represented by the height h _x , which is firmly defined and unchangeable. Both for the removal of a heated workpiece 105 from a furnace level E _I and for equipping a furnace level E _I with a workpiece 105 to be heated, the height h _{i of} the furnace level E _{I is} adapted to the height h _{x of} the pressing tool 404. The height h _{x of} the pressing tool 404 is thus the determining height for the removal and loading of the oven levels (E ₁ ... E _n ). This has the advantage that the time duration t from the removal of a heated workpiece 105 from a furnace level E _i to the placement in the pressing tool 404 for all oven levels (E ₁ ... E _n ) is comparable and as low as possible. The resulting temperature loss is thus also comparable, which in turn leads to a minimization of fluctuations in the quality of the body components.

Fig. 5 shows by way of example the arrangement of two ovens 101 and 101 'and a pressing tool 404. The furnace 101 and a comparable furnace 101' face each other in this example so that the associated drawers 102 each move in the axis of the pressing tool 404 during extension. During the process, in this arrangement, a workpiece 105 after heating is removed from the extended drawer 104 of the oven 101 'and transferred to the die 404. The extended drawer 104 of the oven 101 'is then refitted and retracted. Thereafter, the drawer 102 of the furnace 101 can be extended to remove the heated workpiece 105 and re-equipped after the removal and transfer of the heated workpiece to the pressing tool 404 and retracted again. The process of the mutual extension of the drawers 102 of the ovens 101 and 101 'is repeatable as often as desired.

With this arrangement of the two furnaces 101 and 101 'it is achieved that with the same number of furnace levels in the furnaces 101 and 101' the cycle time of the process is halved and the output on heated workpieces 105 is doubled. If the proposed installation space for the ovens has limited height ratios, it is also possible, the height of the two stoves 101 and To halve 101 'at a constant cycle time and so keep the output of workpieces 105 from the process constant.

101

Höhenverstellbarer Ofen

102

Schublade

103

Horizontale Bewegung

104

Ausgefahrene Schublade

105

Werkstück

106

Verstellmittel

107

Vertikale Bewegung

201

Rotatorische Bewegung

202

Translatorische Bewegung

203

Kugelgewindespindel

204

Motor

205

Kugelgewindestange

206

Kugelgewinde

207

Spindelmutter

208

Kugel

209

Kugelumlauf

401

Transfervorrichtung

402

Greifer

403

Horizontale Bewegung

404

Preßwerkzeug

LIST OF REFERENCE NUMBERS

101

Height adjustable oven

102

drawer

103

Horizontal movement

104

Extended drawer

105

workpiece

106

adjustment

107

Vertical movement

201

Rotatory movement

202

Translational movement

203

Ball screw

204

engine

205

Ball screw rod

206

ball screw

207

spindle nut

208

Bullet

209

recirculating ball

401

transfer device

402

grab

403

Horizontal movement

404

press tool

Claims (14)

1. A method for treating workpieces, in which the workpieces are heated in a furnace in several horizontal furnace levels (E₁ ... E_n), whereby the furnace levels (E₁ ... E_n) are arranged vertically one above the other and each furnace level (E₁ ... E_n) is at a height (h₁ ... h_n), and whereby each furnace level (E₁ ... E_n) is configured to hold at least one workpiece, and, after the workpieces have been heated, they are removed from the furnace levels (E₁ ... E_n) in a defined order,
   characterized in that
   the furnace levels (E₁ ... E_n) are moved stepwise vertically for purposes of removing the heated workpieces, so that each of the heights (h₁ ... h_n) of the individual furnace levels (E₁ ... E_n) changes, whereby the furnace levels (E₁ ... E_n) are moved stepwise vertically in such a way that the height (h₁ ... h_n) of each individual furnace level (E₁ ... E_n) from which at least one workpiece is removed corresponds to a fixed defined removal height h_x, and each individual furnace level (E₁ ... E_n) is at the removal height h_x for a time period t > 0, whereby the position of the furnace levels (E₁ ... E_n) relative to the furnace is fixed and the furnace is moved stepwise vertically by adjustment means to allow the removal of the heated workpieces from the furnace levels (E₁ ... E_n).
2. The method according to claim 1, wherein a lifting system or a pulling system is used as the adjustment means.
3. The method according to one of claims 1 to 2, wherein the workpieces are removed from the furnace levels (E₁ ... E_n) at the removal height h_x by means of a transfer device.
4. The method according to claim 3, wherein the transfer device picks up the workpieces at the defined removal height h_x during the removal and it transports them away, at least partially horizontally.
5. The method according to claim 4, wherein the transfer device picks up the workpieces at the defined removal height h_x during the removal and transports them away horizontally at the defined removal height h_x.
6. The method according to one of claims 1 to 5, wherein, after the removal of a heated workpiece from one of the furnace levels (E₁ ... E_n), a new workpiece that is to be heated is placed into the same furnace level (E₁ ... E_n).
7. The method according to one of claims 1 to 6, wherein, in order for the workpieces to be heated in the furnace levels (E₁ ... E_n), they are placed into drawer elements, and a drawer element is pulled out horizontally at the removal height h_x and a workpiece is removed from the drawer element, and then the drawer element is pushed back again.
8. A device for treating workpieces, comprising a furnace having several horizontal furnace levels (E₁ ... E_n) in which workpieces can be heated, whereby the furnace levels (E₁ ... E_n) are arranged vertically one above the other and each furnace level (E₁ ... E_n) is at a height (h₁ ... h_n), and whereby each furnace level (E₁ ... E_n) is configured to hold and to allow the removal of at least one workpiece,
   characterized in that
   the device has adjustment means to move the furnace levels (E₁ ... E_n) stepwise vertically, whereby these adjustment means are configured in such a way that they can change the individual heights (h₁ ... h_n) of the individual furnace levels (E₁ ... E_n), and they can move the furnace levels (E₁ ... E_n) stepwise vertically in such a way that the height (h₁ ... h_n) of each individual furnace level (E₁ ... E_n) corresponds to a fixed defined removal height (h_x) and each individual furnace level (E₁ ... E_n) can be held at the removal height (h_x) for a time period t > 0, whereby the position of the furnace levels (E₁ ... E_n) is fixed relative to the furnace and the adjustment means are configured in such a way that they can move the furnace stepwise vertically.
9. The device according to claim 8, wherein the adjustment means are configured as a lifting system or a pulling system.
10. The device according to one of claims 8 to 9, comprising a transfer device that is configured to remove the workpieces from the furnace levels (E₁ ... E_n) at the removal height h_x.
11. The device according to one of claims 8 to 10, wherein the transfer device is configured in such a way as to pick up the workpieces at the defined removal height h_x and to transport them away, at least partially horizontally.
12. The device according to claim 11, wherein the transfer device is configured in such a way as to pick up the workpieces at the defined removal height h_x and to transport them away horizontally at the defined removal height h_x.
13. The device according to one of claims 8 to 12, wherein the transfer device is configured in such a way that, after the removal of a heated workpiece from one of the furnace levels (E₁ ... E_n), it can place a new workpiece that is to be heated into the same furnace level (E₁ ... E_n).
14. The device according to one of claims 8 to 13, wherein drawer elements to hold workpieces are provided in the furnace levels (E₁ ... E_n), whereby a drawer element can be moved horizontally at the removal height h_x.

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