HUE025061T2 - Method and device for heating workpieces - Google Patents

Description

Method and device for heating workpieces P$0if The in vention relates to a method for treating workpieces^, in which the workpieces are heated in several horizontal furnace levels in a furnace* whereby the foroace levels are arranged vertically one above the other and each furnace level is at a certain height. Here, each furnace level is configured to hold at least one workpiece, and, after the workpieces have been heated, they are removed from the furnace levels in a defined order. f0ÖÖ2| The invention also relates to a device or furnace for carrying out this method. |ÖÖÖS| Among the most important objectives of the vehicle industry nowadays and in the nature are reducing fuel consumption, lowering the €Ch emissions and improving occupant safety,. A widely used way to reduce fuel consumption and thus to lower the €(¾ emissions is, for example, to reduce the weight of the vehicle, However, in order to attain an improvement in the occupant safety at the same time, the structural steels used for car bodies have to be stronger while weighing less. |8ÖÖ4j Consequently, there is a growing interest in car body structural steels that have a favorable ratio of strength to weight. This is normally achieved by the proeess of so-called hot- working or hot-forming. Here, a sheet metal pari is heated to approximately StHFC to 1000°C fM7TTfo 1812®f] andsubsequentiy shaped and quenched in a cooled fool. As a result, the strength of the pari increases by up to a factor of three, Thanks to the combination of heat treatment, shaping and concurrent controlled cooling, hot-working allows the cosstmcticri of lightweight and vet stiff car body parts. Ρ§§§! In lie pasi, various furnace concepts lave léén developed for lie leal treatment ofear body structural steels. In particular, the principle of the ecnrinuous furnace las found widespread use for hoi-working. With Ibis type of furnace, the car body structural steels that are ίο he heated are transported 1 hrough the fhrOaee oh workpiece carriers by conveying means. Such conveying means can include rollers, chains or belts» yriierehy the conveying Means cab he provided on several levels In the furnace. P0$$1 Continuous farnaces, however, usually entail the drawback that they take up a great deal, of space because of their lengthwise extension. lleMlbre, in order to achieve space savings, as an alternative, it is also possible to use furnaces having several furnace levels atran^pivhQrizonta|j|r one above the other, which are also called rack furnaces. The individual furnace levels can be provided with drawer elements that arc puled out of the furnace horizontally In order to load and remove workpieces. Preferably, a loading and removal: device Whose height can he adjusted Is used to load and remove workpieces from the individual furnace levels that are arranged one above the other. P®®7} A certain amount of time is needed lor the subsequent transport of the healed workpieces from such a rack furnace to the site of the subsequent shaping. During this time, the workpieces cool off as they are mo ved: throat the ambient air. Due to the height dil&euces: of the individ ual furnace levels of the rack furuaee, the times for the iMnsport of the Individual workpieces differ*. Those different times translate into different. temperature losses for the workpieces.

These difierent temperature losses. In turn, can lead to differences In the quality of the car body parts that are to be manufactured. fUiÖSJ U.S. Pat, No. 6,22? J48 Bi discloses a method for the treatment of workpieces in which Me workpieces are heated in several horizontal furnace levels in a furnace. The furnace levels are arranged vertically one above the other, vitoreby each furnace level stáTa ^vmlii%hL'Bach.^ata©&:level is configured to hold one workpiece, After the heating process, the workpieces are removed from the furnace levels in a defined order. For iris purpose, the furnace levels are moved vertically stepwise;, SO: that the appertaining heights of fire individual furnace levels change. In this process, the furnace levels are moved: vertically stepwise in such a way that the height of the specific furnace level from which a workpiece is removed corresponds to a feed defined removal height, and the spéciik furnace level remains at the removal height for a certain period of time. However, depending on the geometry of the workpieces, the removal is difficult, as a result of which different periods of time can he needed for the gripping procedure.

German patent speeificafion DE 10 2006 020781 B3 discloses a furnace that is used for heating steel slugs and that lias several furnace levels arranged horizontally one above the other, whereby each furnace level is provided to hold at least one steel slug and whereby means are provided In each furnace level to move die steel slugs duhng tfk heating procedure. 1’ÖÖlÖf German Preliminary Published Application DE 199 48 606 A! discloses: a method for tempering components, for example, semicondiptor circuits,: printed circuit boards and the like, in which the components are conveyed; on carriers through an entrance sit into a tempering housing provided with tempering members and then through an exit slit that is opposite tram the entrance slit, 'fire carriers are accommodated in the housing: by a magazine that is equipped, with adjacent holders and that, after tie fel holder has been loaded, is Moved stepwise in a direction out of a starting position into consecutive holding positions in which the Individual holders of the magazine are loaded one alter the other. Once all of the holders have been loaded, the filled magazine is moved hack out of the end position thus reached in the opposite direction in a last return movement back into its starting position In which a carrier is led through the entrance slit and, once the magazine has been filled, the tempered carrier in the magazine that was ülted first is removed through the exit slit and, with the consecutive loading of the individual holders of the magazine, the individual tempered carriers can he removed consecutively. |0ii|| Before this backdrop, an objective of the invention is to put forward a method by means of which workpieces, especially car body parts, can be heated up so that they can be: snhseqneniy teWwoifei, without this resulting In excessive fluctuations in the quality of die finished car body parts.

[0912! Here, by means of the method, the time needed for the transfer of the heated workpieces from the furnace to the sire of the subsequent shaping should be kept as constant as possible and the space requirement tor the furnace used tor heating the workpieces should also beminimixed. |99Ui Another oipeeive of the invention Is to put forward a device for carrying out such a method. |0#Mf This objective is achieved by a method having the features of the independent claim L Advantageous refinements of the method. enstm fenn the subordinate claims 2 to 7. The objective is also: achieved by a device: according to claim 0. Advantageous embodiments of this device ensue ifom the subordinate claims 9 to 14. |09ISj The invention comprises a method for treating workpieces, in which the worl^ieces tlM are to be treated are heated M a immm m several horizontal fhroaee levels pj.... Εβ) that are arranged vertically one above the other. Bach furnace level (Ej... ET!) is at a certain height (hi.,. fa«), and can hold at least one workpiece that is to be heated. Alter the beating process, the workpieces are removed front tire furnace levels (Es... £*} in a defined order. The furnace levels pi... E«) am moved stepwise vertically ferpurposes of removing the heated workpieces, so that each of the heights (h·... 1¾} of the individual furnace levels pr... Ε») changes, lie stepwise vcrieal movement takes place in such a way that the height (hi ,., h«) of each indi vidual fun-ace level (Hj.. . 1¾ from which at least one heated workpiece is removed corresponds to a. fixed defined removal height 'hi and thai» in ibis process^ saei: individual furnace level (¾ ,,, :¾ is at. tie removal height h* for a time $mfaé t > Ö. fSTOS] The position of the furnace levels (E;. 1½) relative to the femace is feed; and the furnace is moved stepwise vertically by^ m|oshneiit means to allow the removal of the heated workpieces from the furnace levels (1¾... E0, One oMhodinteut of the method uses a lifting system as the adjustment means, whereas anofeer enfeodinmnt uses a pulling system. PS1?| In a refinement of the method, the heated workpieces are removed Éom fee fesace levels (E* ... Ε») at the removal height h* by means of a transfer device, in this process, the removal takes place in such a way feat fee transfer device picks up the workpieces at: the defined removal height hK and it transports them away, at least partially hortáofealy. For example, fee workpieces arc transported away horizontally at the defeed renmval height hx. Ρ§ΐ!8| In a refinement of the method, after the removal of a heated workpiece fern one of fee furnace levels (1¾ ... if.), a new workpiece feat is to he treated is placed into the same furnace lev el (1¾ ... iy, In another embodiment of fee method, the weekpieces arc placed into drawer elements that are arranged on the individual imnace levels. In this process;, a drawer element is polled out horizontally at fee removal height hx, a workpiece is removed, and then the drawer element is pushed hack again, pÖl9 j The invention also comprises a device for treating workpieces, comprising á furnace having several horizontal furnace levels (E;... E„) that are arranged vertically one above the other and in which workpieces can be heated. Each furnace level (E?... E{i) is at a height (h*... h„) and Is configured to hold and to allow the removal of at least one workpiece. The device has adjustment means to move the tornácé levels (E>,,, Bti) stepwise vertically, and they are configured in such a: way feat they can change the individual heights ,,, hJ5) pitin individual furnace levels (1¾ ... En). In this process, the adjustment means can move the female levels pe ^ MS stepwise vertically Is such a way that the height (h> ,,, ^}of eackindra level (¾.,, 1:½} corresponds to a .fixed defined removal height (hx) and each individual iivmace level (£ ... Er.) can be held at the removal height (hx) tor a time period t > it. |ÖÖ2§| Here, the position of the furnace levels (Ej .... Ea) is fixed relative to the furnace and the ad.jusirae.nt means are configured ίο. such a way that they can move the furnace stepwise verfieally, One embodiment comprises a lilting system as the adjustment means, whereas another embodiment uses a pulling system, |002f j Preferably; the device according to the invention comprises a transfer device for removing heated workpieces from the furnace levels p*,,E*,) cl the removal height hx. This transfer device is also configured to load the furnace levels with the workpieces that are to he heated. Here;, the transfer device has Mtem to pick up the workpieces at the defined removal height 1½ and to transport them away, at least partially horizontally. For example, the transfer device can have means to transport vmrkpfeees away horizontally at the defined remove height hx. |9#22| In a refinement of the device, aier the removal of a heated workpiece from one of Éiefernaee levels (Ej... Eg), the transfer device can place a new workpiece that is to be heated into the same furnace level (Es „. E»). In another embodiment of the device, the furnace levels (E,<.,, £,,) comprise drawer dements that am provided to hold workpieces and that can be moved horizontally at the removal freight hx. |0E23| The described method and the device for treating workpieces have Été advantage that workpieces can. he furnace that takes up less space and, after they have been heated, they can always be removed at the same height from the furnace. For this purpose, the fersaee has several femace levels (Ej... E„) whose height (h,.. . h„) can he systetnMieaiy changed and can therefore be adapted to a fixed defined removal height hx. The appertaining height (h; ... h<,)of the irmace levels (Ej 1¾) is changed iumh case,.it corresponds to the removal height hx, so that workpieces from the furnace levels eaa always he removed am! pmfeably also loaded at the removal height hv The stepwise vertical movement of the furnace levels (Hi... iy required tor this paposé is made possible through the use of adjustment means. f 0§$4§ Thus, the invention diverges írom continuous .furnaces in which the workpieces are moved one after the other through a furnace in order to be heated. It also diverges Som height-adjustable removal devices that are used in rack Amacesto workpieces.

Pi|i| An advantage of the invention as compared to conventional methods for preventing ioctuations in quality during the production of car body parts lies in the fact that tire transfer time of the workpieces horn the furnace to the site of the farther shaping remains constant. Although a continuous furnace also offers this ftossifeiity, it has a considerable lengthwise extension and thus takes up a great deal of space. |0i26| The reason for this is the design of a continuous furnace. With this fhrnace principle, the workpieces that arc to be heated pe transported horizontally on a furnace level through the furnace one after the other on workpiece carriers by means of conveyors, in addition to other parameters, the heating duration as well as the number of parts to he 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 that have to he heated, the greater the lengthwise extension of the continuous furnace. Ρ02Ί| This considerable lengthwise extension of the continuous furnace could he compensated for through the use of a rack furnace. Since the individual furnace levels are situated vertically one above the other with this furnace principle, each workpiece that Is to fee heated is at a different height that has to be accessed so that a removal, device can remove the heated workpieces. Due to the different heights of the furnace levels, each furnace level involves a different transfer distance from the furnace to the she of the further shaping. However, the longer the transfer distance, fee longer it takes for fee heated workpiece to reach the she of the further shaping and the greater the temperature loss of fee heated woriegieee. Lmggíempsrature losses can lead to large Suefearioss In the rpaltv of the ear body parts, even resul ting in failure of the parts. fW28J The Mv^feou advantageorrfy solves this problem in that the height of the furnace levels is adjusted to a fixed delink removal height h*. For purposes of removing the heated workpiece, each furnace level is moved into this removal height h<, and held there for a time period t > 0, so that the transfer distance from the fernace to fee she of the further shaping is the same for each removed workpiece. This translates into a similar temperature loss for each removed workpiece, feepslwms^^ fluctuations in the quality of fee car body parts. p029 j The above-mentioned and of her advmkages, special features and practical refinements of the invention arc illustrated on the basis of the embodiments, which will he described: below wife reference to the figures. P$3§j The figures show the following;

Figure i a schematic view^ of a height-adjustable furnace having several furnace levels lor heating workpieces;

Figure 2 a schematic view of a hall-screw ac tuator;

Figure 3a a schematic flow diagram showing the sequence during the loading of a furnace;

Figure 3b a schematic Sow diagram showing the sequence during fee repeated: loading and removal of workpieces;

Figure 3c m schematic flow diagram showing the sequence during the ending of the healing of workpieces;

Figure 4 a schematic view of various components of a system for the hot- vajricing of workpieces; and

Figure § a schematic view of a system for the hot-working of workpieces with two furnaces. |(ÍBI J Figure 1 sho ws a schematic example of a height-adjustable furnace 101 for heating workpieces, typically having a housing with an opening for loading and removing the wpritpieces that are to he heated. The furnace also comprises any deshed number a of horizontal furnace levels (Ej... B»} on which at least one wofkpieee he heated. The furnace levels (Ej ,,, 1¾} are separated fern each other and are arranged veriieally one above the other, 1¼ example shown in Figure 1 has seven furnace levels, f$0321 Bach of the furnace levels (E;.....E,,) comprises at least one holder to support the workpieces during the heating process. The design of the holders is variable and depends:, among other things, for instance, on the shape of the workpieces dial are to he heated. During the heating process, the workpieces are in the holders and, after the heating process, they are removed from them again. These holders are. for example, drawers 102 that can be pulled out and pushed in with a horizontal movement |#3. l.n Figure 1, the example of a pulled-ou t drawer 104 is shown, in which there is a. workpiece 105. For the heating process, the drawer is loaded with a workpiece IDS, pushed In so étó the workpiece 1Ö5 can he heated, and then pulled out again. |0033} Since the workpieces are not heated horizontally next to each other but rather vertically one abo ve the other, such a furnace principle can minimize the size of the footprint of the furnace 101, This leads to a reduction of the space reflated by the Srnaee 101, Moreover, this furnace principle can minimize the size of tie surface of the furnace 101, which in turn, lowers the energy consumption by reducing the surface losses. PIM| The furnace 101 also has a lilipg system with, which the furnace levels (E'; ,., EjS) can he moved in an up-and-down movement. In tlie height-adjustable furnace 101 shown by way of an example in Figure ! , the iflmg system is; installed on the outside of the bottom of tire furnace 301, so that the movement of the furnace levels (Ej... Er;) translate into a movement of the entire femace 101. litis has the special advantage that the tilling system is not exposed to the high temperatures T of up to I000°C |1832 °F] that prevail in the furnace and consequently, said lifting system does not have to he able to withstand these temperatures. Another advantage is that the housing of the furnace 10.1 only has to surround the furnace levels ¢1¾ -.-1¾. along with all of the accessories that are needed to heat the workpieces 105. As a result, it is not necessary to heat tap any additional volume inside the furnace 101, and this, among other things, leads; to an optimizMion of the energy demand of the furnace 101.

Pi3S| The lifting system is,: for example, an adjustment means 106 that can change Été height of the furnace .101 by making averftea! mc^eni^nl 107. In Figure 2 J: a hall-screw actuator is shown as an example of an adjustment mepsp 106. Ball-screw actuators are screw-type actuators for converting a rotatory movement 201 into a OansMory movement: 202. Á component of the ball-screw actuator ts a ball-screw spindle 203 that is driven: by a motor 204 and that executes the rotatory movement 201. The hail-screw spindle 203 consists of a hail-screw rod 205 in the form of a cylindrical round bar on which a ball screw 206 has been placed. A spindle nut 207 that executes the uansiatory movement 202 Is no.n-rofaiahly mounted on the ball-screw7 spindle 203. Bails 208 follow a bap orbit 200 so that they can circulate inside the spindle nut 207. 1#§36J Very large forces can: be applied by means of a hall-screw actuator. This is especially advantageous in view of the great weight of the furnace 101 that has fo be .moved when the height 'is adjusted. Morpvefi thanks to the high mechanical efficiency of > 90% of a bail-screw actuator, its use is particularly advantageous for the requisite cycle times between foe loading and the removal of the workpieces, said times being in the range of about 10 seconds . Additional advantages of a ball-screw actuator are especially its lew wear and tear as well as the resultant long service life of the actuator, the high degree of postioning and repeatability precision as well as the high movement, speeds that can be achieved. P§37| In one embodiment, the spindle: nut 20? is driven, by foe motor 204 and thus moved relative to the feail-serew spindíe 203. As a result, the spindle nut 20? executes a. rotatory movement 201, whereas the non-rotafably mounted hall-screw spindle 203 executes a iranslat.ory .movement 202. In pother embodiment, instead of the ball-serew actuaiOA a roller-screw actuator is used in which rollers are used instead of the halls 208. However, other sd|ustment means 10b can also be used, |§038] As an alternative, any other suitable devices can be used as the traction devices. Another embodiment of the invention uses, for example, a set of pulleys or chain-type hoists with lift chains. Cost savings can be achieved, particularly in places that already have installations for traction devices. In order to reduce foe actuator power needed and thus the energy requirement of traction devices, it is possible to use, for instance, counterweights. ft03#f in pother embodiment, rigid chain actuators can be used to adjust foe height of the furnace 101. Rigid chain actuators are special chains which, in contrast to the known puling chains, stiffen in the pushing direction, but which can still be delected over sprockets. The pushing capability Is achieved by specially shaped: chain links that engage with, each other with a positive fit. and that are supported with very little play. Hte geometry of the link plates prevents the chain from buckling when subjected to the pressure load exerted by the weight of the furnace 101. Consequently, rigid chain actuators time don as rigid telescoping actuator rods, similar to a conventional linear actuator. Ifoweyer, they are extremely flexible when it. comes to their being stored. The chains cp be deflected to where there is space, and they can he wound op in order to save space. Rigid ©hah* actuators are especially advantageous when It comes to implemeBhng onÍíopnJerh“&amp;ee mo^rteSsof fhe Éen^e levels (E*,.,, 1¾} during the height adjustment, to holding an absolute position for the removal of the workpieces 105, as well as to attaining a compact storage capability lor the rigid Chain actuators, |0O40] The Sow diagram of a process for heating workpieces Is a helyit* adj ustable furnace is shown in Figures 3a to 3c by way of an example. Figure 3a shows the steps during the Icadiiig of the fcnaee op to aproeess point 1, Before the beginning ofthe process, the furnace 101. is heated to a defined temperature T which, for hot-working, is usually 8(I0°C to 1000°C [I472°F to 1832ÖF], Once the defined tempemfnm T has been reached, a lifting system changes the height of the furnace 101 until the height h· of the fiancee level Ej corresponds to a fixed defined:Iheight h* at which the furnace lesel Ip then remains for a time period t '> 0, P04I1 ín this eotdexf the height h refers to the distance between an object point and a reference line or reference snriaee. The distance between the object point and the reference line is preferably ascertained by a direct tneasummenf of the distance, which can be done using a ruler. Here, for example, the bottom surface on which the furnace stands can serve as the reference line so that the height h* corresponds to a certain distance from the bottom, The variable heights of the furnace levels are adapted to this height hx by a vertical movement of the furnace. |ÍÖ42f After the height of the furnace 10.1 has been adjusted, the drawer 102 of the furnace level Es is pulled out, loaded with a workpiece 105 that is to be heated, and subsequently pushed back in. The height of the furnace lif is changed by the lifting system once again so that then the height 1¾ of the furnace level 1¾ corresponds to lie height hs at which the furnace level 1¾ then remains ibr a lime period! > 0. Aierihe height a<§usm^ 101 has been completed, the drawer 102 of the furnace level la is puled out, loaded with a workpiece 105 that is to be heated, and the» pushed back ha. This process is mpeated stepwise until the drawers 102 of ail of the furnace levels (E; ,.. Ε») have been loaded in that the furnace levels are each moved to the defined height hs. pöiSl The workpieces 105 placed into the height-adjustable furnace 101 in this manner are heated in the furnace over a defined holding dine to a defined temperature T that Is, for example, 860°C to 980°€ [1580°F to 1 ?96°F] for some cm· body structural steels. Once the workpiece that is to he removed first has reached the required MU|^ramre, the process point 1 shown in Figure la has been reached. $90441 Once the heating; of the workpieces 105 at the process poin t 1 has been completed, as shown in Figure 3h, this is followed by a another change in fhe height of the furnace 101 by means of the lifting system until the height hs of the furnace level Bj once again eorresponds to the height fp at which the furnace level fn then remains again for a tine period t > 0. lie drawer 102 of the furnace level Fa is pulled out and the heated workpiece 105 is removed from it. lithe entire process is not yet complete, then the drawer 1.(0 is once again loaded with a workpiece 105 that is to be heated and subsequently pushed back In, The height of the furnace 101 Is changed again so that then the height 1¾ of the furnace level 1¾ corresponds to the height hx at which the furnace level 1¾ then once again remains for a time period t > Ö. The drawer 1#1 of the furnace level 1¾ is pulled out. the heated workpiece 105 is removed from it, the drawer 102 is loaded with a workpiece 105 that is to he heated, and subsequently,, the drawer is pushed back m. Tils poeedlipe *s5;rpp#e<i until the drawers 102 of all of the furnace levels ¢1¼ ... E,,) have once again been loaded with workpíeees 105 that are to he heated and that are stisselpeotly heated for the defined holding tinte to the defined temperature T, 10§45| The process of repeatedly heating workpieces 105 in a height-adjustable furnace 101 is ended when the process point 2 shown in Figure 3b has been reached and when, after the removal procedure has been completed, no further workpieces 105 are placed kte the furnace levels IE, i.n order to he heated. Then, Imiuslance, the furnace 101 can be cooled oil The steps during the last removal of heated workpieces from: the indiv^^ are shown, in Figure 3c. 10®46| In one refinement during the process for heating workpieces 105, the possibility exists to load workpieces 105 into and/or to remove workpieces 105 irorn the furnace levels (E: .. . En) in any desired order or even in a varying order. Ms has the advantage that dlderent workpieces 105.. for example, workpieces 105 having diilment thicknesses, ears. he treated fer different holding times in the furnace within one process, which is achieved by controlling the furnace appropriately. |ÖÖ47f Moreover, in one embodiment, it is also possible to load ail of the furnace levels (B?... E;;) with workpieces 105, to remove the workpieces from the furnace levels 0¾ ... E,;) after they have been heated, and only then - alter ail of the workpieces have been removed from the furnace levels (E.:... E*) ~ to once again load the: furnace levels (Ej ... E;i). In another embodiment, not ail of the fhrn&amp;ce levels (¾... E«f are nsed to heat workpieces 1115, Ms Is especially advantageous if only a lew parts are to be heated. Moreover, especially in ease of malfunctions, it. is possible to remove workpieces from the fhmaee levels (Ei... ER), even it the furnace levels (Ej... E«) are not at the height hx. These different embodiments can be implemented in a freely programmable control unit of the entire arrangement. P1948J The workpieces 105 that are to he heated are especially shaped sheet-metal parts made of car body steefrtral steels used lor lot-worked car body parts used ih antomodve construedon, powover, dlSfrrently shaped or nnsbaped workpieces made of other materials can also be heated, pd49| In one embodiment, it is possible to produce workpieces IDS having some different properties that are especially advantageous Eir the above-mentioned oar body parts used In automotive construction. For this purpose, a drawer 102 is pulled out some time before the actual removal of the workpiece 1 OS so that the workpiece 105 partially cools off to a temperature below of the austenite or hardening temperature so that, during the subsequent hot-working, it is not very hard martensite, bot rather a periííe-íerrite structure that is formed in the already-cooled portion, This structure has mnei higher elongation rates and is less fracture-prone in case of a vehicle col lision, pÖSi| Irt the example schematically shown in Figure 4, the heíght-adjustabic furnace 101 is a component of a system for the hoi-working of 'workpieces, After the heating process, a workpiece 105 is removed from the pulled-out drawer 104 of a furnace level S? of the :fnmaee .101 at a height h·:::: hs. The removal is carried out, for example, hv means of a Éansfor device 401 that is equipped with at least one gripper 402 for picking up and laying down wmlqúeees. By way of art example, Figure 4 shows a transfer device 402 with four grippers. After the heated workpiece 1SS has been remo ved, the transfer device 402 executes a movement 403 leading' from the furnace 101 to a pressing tool 404 and transfers the workpiece to the pressing tool 404, |ÖÖ5I] The hot-working process can he carried out using methods and pressing tools that are generally known to the person skilled in the art. The transfer device: 402 lays down the workpiece 105 in the pressing tool 404, and the transfer device 402 subsequently returns from the pressing tool 404 to the furnace 101. f88521 A refinement provides that the: transfer device 401 is configured not only to load a furnace level but also to remove a. workpiece 105 from a furnace level and to further transport it to a pressing; tool 404. For this purpose, on the way from the pressing tool 404 to the famtee 101, the transfer device 401 picks up a workpiece that is to be heated, transports ft to the foruace 101, and places it into one of the furnace levels. P$$31 The height of the pressing tool 404 relative to the floor where it stands is, for example, likewise set by the height kx, which is a fixed defined: height and not variable. The height h; of the furnace level 1¾ is adapted to fee height h* of the pressing tool 404 in order to remove a heated workpiece 105 from the furnace level E· as well as in order to load the furnace level E; with a workpiece 105 that; is to he heated. The height hx of the pressing tool 404 is thus the decisive height for loading workpieces into and removing Workpieces ffom the furnace levels (¾ ... ETj), This has fee advantage that the time period t that transpires between the removal of a heated vmrlpeees 105 írom a furnace level E$ and their placement:

In the pressing tool 404 is similar and as short as possible for all furnace levels (Ih ... Bn). The resultant temperature loss is thus likewise similar, which in turn, leads to a mimiuixation of fluetuations in the quality of the car body parts. f ÖÖ54) By way of an example. Figure 5 shows fee arrangement of two furnaces 101 and 10Γ as well as a pressing tool 404. In fels example, fee ihrndee 101 and a comparable furnace 10 Γ are across írom each other in such a way that, when the appertaining drawers 102 are pulled oat, they each move into the axis of the pressing tool 404. lUtping the process, in this arrangement a workpiece 105 is removed írom the pulkd*out drawer 104 of the foraaee Ι0Γ and transferred to fee pressing loot 404.11¾ puieduafe drawer 104 of the furnace 101 ’ is subsequently loaded once again and pushed hack in. Then the drawer 102 of the furnace 101 can be pulled out in order for the heated workpiece 105 to be removed and, after fee heated workpiece has been removed and then transferred to the pressing tool 404, the drawer 102 can: be loaded once again and pushed back in. The process of alternately pulling out fee drawers 102 of fee furnaces 101 and Ml F ean he repeated as often as desired. pfeSSJ With this arrangement: of the two furnaces 101 and 101 it is achieved that, with the same number of ;toaee levels in fee furnaces 101 and 10Γ, fee cycle time of the process is cut in half and the yield of heated workpieces 105 is doubled. If the available installation space for the furnaces is of a limited height, it is also possible to cot In half fee heights of the two furnaces 101 and 10Γ while maintaining the same cycle time, as a result of which fee yield of workpieces 105 from fee process is kept constant.

Claims (10)

EMERGENCY AND EQUIPMENT FOR REINFORCING WORKING PARTS Claims A method for treating workpieces, wherein the workpieces are heated in a furnace at a plurality of horizontal chambers (Ei ... Eh) or furnace planes, the furnace levels (E? ... EK) being arranged vertically above each other and each furnace color (No. .. E «) is located at an altitude (ht.. H.); and where each furnace plane (Ex... is designed to receive at least one workpiece # or receive it, and the workpieces are taken from the furnace stacks (Ei ... £ a} in a specific order after heating, characterized by being heated) To remove the workpieces, the chest struts (E · ;. ... En) are moved vertically in steps, so that the individual kiln levels (Ei ... E (·.} at each height (... 1¾} vary, the oven levels have been changed (Ej. ... Ε ») are moved vertically vertically so that the height of the respective kiln level (E? ....%) (eu ,,, b») * of which at least one workpiece is lost corresponds to a predetermined height of hx and the relevant furnace level pi., EC) is located for a period of time! ah * take-off height, mimeled: the position of the furnace levels (Ej______E «) relative to the furnace is fixed, and the furnace is moved vertically step by step with the help of adjusting structures to remove the pond heated workpieces from the furnace levels (Ej ... En). The method according to claim 1, wherein the biasing means are a lifting system or a chisel system. The method according to claim 1 or 2, wherein the workpieces are provided by means of a transfer device or transfer device located at the take-off height hx. let's get out of the oven level! (E ·. Er.). The method according to claim 3, wherein the displacement device picks up the workpieces at a predetermined jh * height and at least partially moves them horizontally. δ. The method of claim 4, wherein the relocation device comprises workpieces with predetermined h>; when picked up at elevation it is picked up and transported horizontally at a predetermined height of hx. 6. A method according to any one of claims t-i, wherein one of the furnace fryers is! (¾ ... Er () after a half-heated workpiece is removed, a workpiece to be heated to the same keruene level is delivered (No. E4). 7. An ejector according to any of the claims, wherein the workpieces are placed in drawer elements for heating on furnace levels (Ei ... En), and a drawer element at the hx elevation height is horizontally ejected and a workpiece is removed from the spigot and the fixture is subsequently removed. go back again. 8. An apparatus for treating workpieces, said apparatus having a plurality of horizontal furnace levels (Ei Ea | furnace, which can heat up the furnace levels at the oven level, while the furnace levels (Ei ... £ *) are vertically superimposed on each of these furnace levels. Eh) is located vertically at a height (ha ha), each level of furnace (Ei ... Εκ) is designed to pick up and remove at least one workpiece, characterized in that the apparatus has chest levels. Steps to move vertically step by step, these stand structures are designed to change the respective heights (hi .., 1¾} of each chimney level (Ei ... Er), and the oven levels (Es E «) can be changed step by step. move vertically so that the height of the respective kiln level (Et ... E «) (out ,, .. 1½) is a predetermined takeoff! (hx) corresponds to the current and given furnace level; (Ei ... Ha) for a period t> O a. Hx can be maintained at take-off height, while the position of the take-off levels (Ei ... Ε ») is fixed relative to the furnace, and the adjusting means are configured to move the furnace step by step vertically. The arrangement of claim 8, wherein the adjusting means are provided as a lifting system or a tensioning system. Apparatus according to claim 8 or 9, wherein the apparatus has a relay # structure or a transfer device which is adapted to remove the workpieces from the chimney scales (Ei ... or from the chenees) at the take-off height h *. Apparatus according to any one of claims 10 to 10, wherein the releaser is configured to take workpieces at at least a predetermined take-off height and at least partially extend horizontally. is designed to pick up workpieces at predetermined height h, and transport horizontally at predetermined exit height hx 18. The apparatus of any one of claims 8 to 12, wherein the transfer device is configured to heat one a workpiece can be supplied with a new workpiece for the workpiece from a furnace level (Ei ...) and for the furnaceSk. Apparatus according to any one of claims 14 to 13, wherein at the chene level (Hi Eh) ninetypiece halves are suitable for stitching of the drawer elements # with which a drawer element can be lost at the hx take-off height.