Title of Invention

CONVEYANCE APPARATUS

Abstract

A carrier 3 that is moveably supported on the side of a conveyor 2 is provided with a rotational shaft 4 projecting laterally therefrom. A workpiece 1 is mounted on the rotational shaft 4 in an upright condition, wherein the workpiece 1 is arranged to vertically rotate 3600 in the same plane by rotating the rotational shaft 4 3600 around its axis. With this construction, the workpiece position can be continuously changed to a floor conveyor position, an overhead conveyor position and to the floor conveyor II position without transfer of the workpiece 1.

Full Text

5 THe present invention relates to a conveyance apparatus which allows a workpiece supported by a conveyor to pass through a plurality of treating processes while changing its position, and more particularly to a conveyance apparatus which is suitable for a surface treatment line such as a car body painting line in vehicle manufacture. FurtHcr, tHc present invention relates to a conveyance path connecting a ■ 10 pretreatment process and a drying process, used, for example, for painting parts of a vehicle. 2, Description of tHc Prior Art In a painting line for a vehicle, tHcre are many treating processes such as pretreatment, electrodeposition, washing, painting, and drying and a workpiece is 15 transferred among tHcse treating processes by a conveyor. WHcn painting of a comparatively large body of, for example, a four-wHcel car is required by dipping, as shown in Fig. 17A, a workpiece W which has been transferred on a floor conveyor FC located on a floor is transferred to an overHcad conveyor HC for hanging support. THc overHcad conveyor HG is enabled to move up and down in a vertical manner relative to 20 tHc pretreatment and electrodeposition line. In such a condition, tHc workpiece W is moved vertically for dipping treatment while passing above pretreatment and electrodeposition baths and tHc like and tHcn transferred again to tHc floor conveyor FC. Also, in tHc case of electrodeposition, to obtain fine painting quality, it is 25 known that tHc workpiece is rotated in an electrodeposition paint bath to change its position to a successive variety of positions (e.g. see Japanese Patent Publication No. Hci 6-104920 and Japanese Unexamined Patent Publication No. Hci 2-111481). On tHc otHcr hand, wHcn painting of a comparatively small body of a two-wHcel vehicle is required, as shown in Fig. 17B, it is possible to perform all painting 30 processes using tHc overHcad conveyor HC. Accordingly, it is not necessary to transfer tHc body in tHc middle of tHc painting line as with tHc four-wHceled vehicle. However, as far as tHc dipping treatment is concerned, tHc vertical operation is conducted in tHc same manner as shown above. In tHc following description, a workpiece position of a type in which tHc workpiece is mounted and supported on a floor conveyor is called a floor conveyor position, a workpiece position of a type in which tHc workpiece is hung and supported is called an overHcad conveyor position, and a workpiece position of a type in which tHc workpiece is substantially supported in a level plane at tHc side of tHc conveyor is called a side conveyor position. FurtHcr, rotation in a plane parallel to and perpendicular to tHc direction of travel is called vertical rotation, while rotation in a plane at right angles to tHc direction of travel is called horizontal rotation. Also, for example, in tHc manufacture of a fuel tank, body frame or tHc like as parts for a motorcycle, wHcn tHc tank or tHc frame which undergoes electrodeposition painting and tHc tank or tHc frame which does not undergo ectrodeposition painting are transferred on a common line, as shown in Fig. 23, a diverging point is provided in a line at tHc upstream side of an electrodeposition bath and a line A is used for tHc workpiece being painted, wHcreas a by-pass line B is used for tHc workpiece not being painted and tHcse lines join at tHc junction at tHc downstream side of tHc electrodeposition bath. FurtHcr, in tHc case of, for example, painting parts or tHc like of a vehicle, as shown in Fig. 27, for example, after a workpiece W conveyed by means of a carrier G along a workpiece conveyance path H has been immersed in an electrodeposition bath (not shown) at a pretreatment process A, tHc workpiece W after being removed from tHc electrodeposition bath is transferred to a drying process C to dry a paint film. At this time, in order to prevent hot air from tHc drying process C from entering tHc pretreatment process A, a hot air isolating zone B is generally provided between tHc pretreatment process A and tHc drying process C. THc hot air isolating zone B is shortened to save a space by having an equipment formed in such a construction that, a workpeice conveying path H of tHc hot air isolating zone B slants, and a workpiece conveying path H of tHc drying process C is located at a higHcr position, tHcreby making it difficult for tHc hot air from tHc drying process C to enter tHc pretreatment process A. SUMMARY OF THc INVENTION In a process wHcrein tHc workpiece position must be changed to tHc floor conveyor position and tHc overHcad conveyor position, if tHc workpiece has to be transferred from one conveyor to anotHcr wHcnever tHc workpiece position is changed, loss of time is caused. It is tHcrefore desired not to transfer the workpiece while being conveyed at least in one continuous process even though the workpiece position is changed. FurtHcr, in a method such as a dipping treatment wHcrein a conveyance line is continuously changed vertically, tHc proportion of time not suitable for dipping but required only for moving tHc workpiece in and out of a bath becomes large relative to tHc substantial dipping time of tHc workpiece. Accordingly, it is also desired to improve this loss of time. Also, in tHc case of tHc overHcad conveyor, tHcre is some possibility that tHc painting quality deteriorates wHcn dust or tHc like falling from tHc overHcad conveyor adHcres to tHc workpiece. It is tHcrefore desired to realize a conveyance method which keeps such falling substances from adHcring to tHc workpiece. It is tHcrefore a first object of tHc present invention to solve tHc above-mentioned disadvantages. Also, if tHc above-mentioned by-pass line B is installed, tHcre are disadvantages that tHc equipment construction including tHc conveyance apparatus is large in size, and tHc equipment cost is high, and conveying control becomes complicated. It is tHcrefore a second object of tHc present invention to solve tHc above-mentioned disadvantages. FurtHcrmore, tHc hot air isolating zone B having tHc slanting conveying path as mentioned above is still too long, tHcrefore, it is preferable to furtHcr shorten tHc zone B. It is tHcrefore a third object of tHc present invention to minimize tHc distance between a pretreatment process and a drying process and to reduce tHc equipment space furtHcr, in a conveyance apparatus in which difference in Hcight is provided for a workpiece conveyance path for tHc pretreatment process and a workpiece conveyance path for tHc drying process. To solve tHc above-noted disadvantages, according to tHc first invention, a conveyance apparatus has a conveyor for supporting a workpiece and is adapted to allow tHc workpiece to pass through a plurality of treating processes while changing a workpiece position, wHcrein a position control mechanism for changing tHc workpiece position is provided ao that tHc workpiece position required for each treating process can be continuously changed without transfer of tHc workpiece. According to tHc present invention, tHc workpiece is conveyed to a plurality of treating processes which require different workpiece positions while Hcing supported by tHc same conveyor and tHc position control mechanism is provided to allow tHc workpiece to be changed to tHc most suitable workpiece position for each process. Thus, it is no longer necessary to transfer tHc workpiece to anotHcr type of conveyor for each process and continuous conveyance is possible. It is tHcrefore possible to reduce tHc number of transfer processes that have been required for tHc conventional conveyance apparatus and improve tHc efficiency for conveyance of tHc workpiece among tHc plurality of processes. This position control mechanism can be arranged to eitHcr control tHc workpiece position to provide a floor conveyor position in which tHc workpiece is supported above tHc conveyor and an overHcad conveyor position in which tHc workpiece is hung and supported below tHc conveyor; or to allow tHc workpiece to be supported substantially in a level plane on tHc side of tHc conveyor to reaUze a side conveyor position; or to continuously control tHc workpiece position to provide tHc floor conveyor position, tHc overHcad conveyor position and tHc side conveyor position. THc position control mechanism can also be arranged to realize all of tHc above positions. Also, since tHc floor conveyor position and tHc overHcad conveyor position are controllable, continuous treatment can be carried out without transfer of tHc workpiece even in such a treating process as tHc dipping treatment wHcre tHc floor conveyor position and tHc overHcad position are alternately required. If tHc system is controlled to provide tHc side conveyor position, tHc workpiece can be supported substantially in a level plane laterally from tHc conveyor. It is tHcrefore effective in such a process, in particular a painting process, to prevent substances falling from tHc conveyor from adHcring to tHc workpiece. FurtHcrmore, if tHc floor conveyor position, tHc overHcad conveyor position, and tHc side conveyor position are controlled in combination, it is possible to easily realize such complicated position control wHcre tHc workpiece is required to rotate to allow each surface to face a specified direction in sequence. THc position control mechanism also makes it possible for tHc workpiece position to be changed eitHcr to provide vertical rotation within a plane parallel to tHc direction of travel of tHc conveyor or to provide horizontal rotation that rocks within a plane perpendicular to tHc direction of travel, or makes both vertical and horizontal rotation possible simultaneously. This kind of control between tHc floor conveyor position and tHc overHcad conveyor position can be realized by rotating tHc workpiece vertically. It is suitable for a continuous conveyance method that controls tHc workpiece position while continuously conveying tHc workpiece. In this case, if tHc rotational shaft projecting laterally from tHc conveyor is arranged to support tHc workpiece and rotated around its axis, tHc workpiece can be vertically rotated. Also, control between tHc floor conveyor position and tHc overHcad conveyor position and if necessary, control among tHc workpiece positions including tHc side /conveyor position can be realized by rotating tHc workpiece horizontally. In this case, control can be easily realized by rocking tHc arm member within a plane wHcre tHc horizontal rotation is made or by rotating a moveable portion provided on a part of tHc conveyor togetHcr with tHc workpiece. It is especially suitable for a tact conveyance method that intermittently conveys tHc workpiece. Moreover, tHc conveyance apparatus is characterized in that a part of tHc conveyor is arranged to serve as a moveable portion and a rotational means is provided to rotate tHc moveable portion in a plane at right angles to tHc direction of travel of tHc conveyor, wHcrein tHc rotational means rotates tHc moveable portion togetHcr with tHc carrier. According to tHc present invention, a part of tHc conveyor is provided with a moveable portion and wHcn tHc moveable portion is rotated by a rotational means, not only tHc moveable portion, but also a carrier that is supported hy tHc moveable portion rotates integrally. It is tHcrefore possible to rotate a workpiece horizontally so as to change its position freely to a floor conveyor position, an overHcad conveyor position and tHc like. Thus, it is no longer necessary to transfer tHc workpiece even wHcn tHc workpiece position must be changed for every continuous process, tHcrefore loss of time can be reduced. Accordingly, it is particularly suitable for a tact treatment wHcre conveyance is intermittently stopped at every process for a necessary treatment. In this case, tHc carrier can move like a monorail on tHc peripHcry of tHc conveyor that passes through tHc center portion of tHc carrier. Also, a carrier feeding means for moving tHc carrier on tHc conveyor in tHc direction of travel is provided parallel to tHc conveyor and tHc carrier can be provided with a flange portion which always engages tHc carrier feeding means. If tHc carrier is supported like a monorail on tHc conveyor, tHc supporting construction of tHc carrier is simplified and strengtHcned. Thus, conveyance of tHc workpiece can Hc stabilized and it is especially favorable wHcn a Hcavy workpiece must be supported. In addition, if tHc carrier is provided with a flange which engages a carrier feeding means provided parallel to tHc conveyor, tHc carrier is always maintained in tHc engaging condition with tHc carrier feeding means even if tHc carrier rotates and movement of tHc carrier is enabled. On tHc otHcr hand, in a method wHcre tHc carrier is supported on one side of tHc conveyor, since tHc workpiece can be supported laterally away from tHc conveyor, tHcreby keeping substances falling from tHc conveyor from adHcring to tHc workpiece. FurtHcr, it is possible to convey tHc carrier in tHc direction of travel while supporting it on one side of tHc conveyor. THc rotational means may be a step motor that can be situated within tHc conveyor. Also, since a part of tHc conveyor is arranged to serve as tHc moveable portion, it is possible to strengtHcn tHc moveable portion and simplify tHc construction comparatively. THc rotational means can be easily formed with a step motor and tHc like. WHcn tHc step motor is used, it can be easily housed inside a hollow portion of tHc conveyor, and tHc rotational direction and angle are controllable. In tHc second invention, a conveyance apparatus is provided for mixed workpieces in which a workpiece conveying path is provided above a treatment bath, and a workpiece to be immersed in tHc treatment bath and a workpiece not to be immersed in tHc treatment bath are adapted to be mixediy conveyed by means of a carrier which is capable of running along a travelling rail of said workpiece conveying path, characterized in that a carrier inversion mechanism is provided in at least one portion of said workpiece conveying path above said treatment bath, and said workpiece to be immersed in said treatment bath is inverted in a plane at right angles to said conveying path by said carrier inversion mechanism to allow tHc workpiece to pass said treatment bath. WHcn tHc workpiece is transferred toward tHc treatment bath, tHc workpiece which is not be immersed in tHc treatment bath is allowed to travel in a condition in which tHc travelling course of tHc workpiece passes above tHc treatment bath, wHcreas tHc workpiece which is to be immersed in tHc treatment bath is converted to a position in which tHc travelling course of tHc workpiece passes inside tHc treatment bath. THc carrier inversion mechanism is so designed that tHc transporting course of tHc workpiece is changed vertically by inverting tHc workpiece togetHcr with tHc carrier by 180" , For example, a center of an inversion axis is set to be spaced to a certain extent from tHc workpiece. Also, tHc treatment bath can be applied, for example, to a dipping bath for electrodeposition painting, a dipping bath for paint pretreatment, and otHcr dipping baths. FurtHcr, tHc carrier inversion mechanism is enabled to be inverted togetHcr with tHc travelling rail of tHc workpiece conveying path. Since tHc carrier inversion mechanism is enabled to be inverted togetHcr with tHc travelling rail of tHc workpiece conveying path, it is possible to simplify tHc inversion mechanism for tHc workpiece which is supported by tHc carrier. FurtHcrmore, tHc carrier inversion mechanism is paired to position an intermediate travelling portion between tHc upstream side and tHc downstream side of tHc workpiece conveying path above tHc treatment bath. In this manner, since a pair of carrier inversion mechanism is provided on both tHc upstream and downstream sides and tHc intermediate travelling portion is also provided tHcrebetween, it is possible to secure sufficient immersion time for tHc workpiece and satisfactory immersion treatment can be performed. Also, tHc traveling rail is formed as a double, upper and lower rail, structure. THcrefore, because tHc travelling rail has this double, upper and lower rail, structure, for example, in both cases wHcre tHc workpiece not immersed in tHc treatment hath is moved while being supported above tHc carrier, and wHcre tHc workpiece immersed in tHc treatment bath is moved while being supported below tHc carrier, it is possible to prevent interference between a conveying stand installed on tHc floor surface and tHc carrier. WHcn tHc intermediate travelling portion is provided and both tHc immersed workpiece and tHc non-immersed workpiece are caused to pass this intermediate travelling portion, for example, tHc conveying stand is positioned between tHc upper and lower rails. If tHc workpiece is supported above tHc carrier, tHc carrier is caused to move along tHc upper rail. If tHc workpiece is supported below tHc carrier, tHc carrier is caused to move along tHc lower rail. Thus, tHcre is no interference between tHc conveying stand and tHc carrier. According to tHc third invention, a conveyance apparatus is provided in which different Hcights are provided for a workpiece conveyance path for a pretreatment process and a workpiece conveying path for a drying process, a connecting workpiece conveyance path being provided at an intermediate portion of tHc two processes, characterized in that on said connecting workpiece conveyance path, a conveyance path lifter mechanism is provided to transfer a workpiece conveyance from tHc workpiece conveyance path for tHc pretreatment process toward tHc workpiece conveyance path for tHc drying process. Hcrein, a conveyance path lifter mechanism is a mechanism capable of switching and connecting a lower workpiece conveyance path and an upper workpiece conveyance path, by at least one portion of a connecting workpiece conveyance path which is permitted to move up and down vertically. In addition, wHcn tHc workpiece is transferred by means of a carrier or tHc like from tHc workpiece conveyance path for tHc pretreatment process to tHc connecting workpiece conveyance path, tHc workpiece is displaced upward at at least one portion of tHc connecting workpiece conveyance path togetHcr with tHc carrier hy means of tHc conveyance path lifter mechanism, wHcreby tHc carrier or tHc like is connected to tHc workpiece conveyance path for tHc upper drying process, and tHc workpiece is connected to tHc drying process. In this manner, if tHc workpiece is displaced and transferred vertically by tHc conveyance path lifter mechanism of tHc connecting workpiece conveying path for connection, tHc distance between tHc pretreatment process and tHc drying process can be shortened, thus saving space. Also, in a conveyance apparatus in which different Hcights are provided between a workpiece conveyance path for a pretreatment process and a workpiece conveyance path for a drying process, a connecting workpiece conveyance path is provided at an intermediate portion of tHc two processes. On tHc connecting workpiece conveyance path, a conveyance path reversing mechanism is provided to transfer a workpiece conveyed from said workpiece conveyance path for said pretreatment process toward said workpiece conveyance path for said drying process. Hcrein, a conveyance path reversing mechanism is a mechanism which is capable of switching tHc lower workpiece conveyance path and tHc upper workpiece conveyance path and connecting tHcm, by reversing at least a part of tHc connecting workpiece conveying path 180" In addition, wHcn tHc workpiece is transferred by means of a carrier from tHc workpiece conveyance path for tHc pretreatment process to tHc connecting workpiece conveyance path, tHc workpiece is reversed by 180 at at least one portion of tHc connecting workpiece conveyance path togetHcr with tHc carrier by means of tHc conveyance path reversing mechanism, wHcreby tHc carrier is „ connected to tHc workpiece conveyance path for tHc upper drying process, and tHc workpiece is conveyed to tHc drying process. in this manner, even though tHc connecting workpiece conveyance path is reversed 180° by means of tHc conveying path reversing mechanism of tHc connecting workpiece conveyance path and tHc workpiece is transferred, tHc distance between tHc pretreatment process and tHc drying process can be shortened , thus saving space. BRIEF DESCRIPTION OF THc DRAWINGS THc above and otHcr objects, features and advantages of tHc present invention will become more apparent from tHc following description wHcn taken in conjunction with tHc accompanying drawings. Fig. 1 is a process chart for a complete body painting line according to a first embodiment (Figs. 1 to 8); Fig. 2 is a side view showing a floor conveyor position; Fig. 3 is plan view tHcreof; Fig. 4 is a front view tHcreof; Fig. 5 is a cross sectional view showing basic parts of a vertical rotation mechanism; Fig. 6 is a side view tHcreof; Fig. 7 is a view showing a horizontal rotation mechanism; Fig. 8 is a view showing position control of a workpiece in electrodeposition coating; Fig. 9 is a cross sectional view of a conveyor on tHc side of a movable portion according to a second embodiment (Figs. 9 to 13); Fig. 10 is a plan view tHcreof; Fig. 11 is a cross sectional view taken along tHc line 11 - 11 of Fig. 9; Fig. 12 is view showing an operation condition of Fig. 11; Fig. 13 is a view showing position control of tHc workpiece in electrodeposition coating; Fig. 14 is a cross sectional view of tHc conveyor on tHc side of tHc moveable portion according to a third embodiment (Figs. 14 to 16); Fig. 15 shows a plan view tHcreof togetHcr with an operation; Fig. 16 is a view showing tHc moveable portion from tHc front side of tHc direction of travel F togetHcr with tHc operation tHcreof; and Fig. 17 is a process chart for a conventional painting line. Fig. 18 is a process chart for a complete body painting line according to an embodiment; Fig. 19 is a side view explaining tHc structure of tHc conveyance apparatus, (a) being a view explaining tHc case wHcre a workpiece is not immersed in an electrodeposition bath, and (b) being a view explaining tHc case wHcre tHc workpiece is immersed in tHc electrodeposition bath; Fig. 20 is a view explaining a n inverted condition of a carrier inversion mechanism viewed from tHc front; Fig. 21 is a view explaining a drive source of tHc carrier inversion mechanism; Fig, 22 is a view explaining a relationship of a carrier with a conveying stand in a case of one rail; and Fig. 23 is a view explaining a conveyance apparatus of tHc prior art. Fig. 24 is an explanatory view of a conveyance apparatus using a conveying path lifter mechanism; Fig. 25 is an explanatory view of a conveyance apparatus using a conveying path inverting mechanism viewed from its front direction; Fig. 26 is an explanatory view of a conveyance apparatus using a conveying path inverting mechanism viewed from its side direction; and Fig. 27 is a conveyance apparatus of tHc prior art. DETAILED DESCRIPTION OF THc PREFERRED EMBODIMENTS THc first preferred embodiments for performing body painting of a motorcycle will be described Hcreunder with reference to tHc accompanying drawings. Fig. I is a flow chart of a complete painting line in which each action of loading and jig attachment A, pretrcatment B, electrodeposition coating C, electro-deposition drying D, finish coating E and finish drying F is continuously conducted in sequence. Circled figures in tHc flow chart show tHc processes of Fig. 1. (THc process number in tHc description is shown by tHc corresponding parentHcsized numbers. Identical indication tHcreafter.) First, in tHc process of loading and jig attachment A, a workpiece 1 which is tHc frame body of a motorcycle has been hung and conveyed by an overHcad conveyor HC of a welding line which is a process previous to this painting line. THc workpiece 1 is tHcn mounted on a conveyor 2 in a floor conveyor position through a carrier 3 (1). Now, in tHc process of pretreatment B, tHc workpiece position is continuously changed by rotating tHc workpiece 1 upward to tHc floor conveyor position and downward to tHc overHcad conveyor position so as to perform each process of degreasing (2) (tHc overHcad conveyor position), washing and surface preparation (3) (tHc floor conveyor position), cHcmical conversion treatment (4) (tHc overHcad conveyor position), washing (5) (tHc floor conveyor position), washing (6) (tHc overHcad conveyor position), and pure water washing and draining (7) {tHc floor conveyor position). In tHc process of electrodeposition coating C, tHc workpiece position is also changed by rotating tHc workpiece 1 upward to tHc floor conveyor position and downward to tHc overHcad conveyor position so as to perform each process of tHc electrodeposition coating (8) (tHc overHcad conveyor position), washing (9) (tHc floor conveyor position), washing (10) {tHc overHcad conveyor position) and pure water washing (11) (tHc floor conveyor position). In tHc process of pretreatment drying D, tHc floor conveyor position is maintained to allow tHc workpiece 1 to pass through an electrodeposition drying furnace without changing tHc workpiece position (12). In tHc finish coating E, tHc workpiece 1 is rotated from tHc floor conveyor position to tHc overHcad conveyor position and conveyed into a finish-coating booth of a spray type (13). THc workpiece 1 in tHc finish-coating booth is tHcn rotated at right angles until it is at tHc side conveyor position (14), tHcn tHc workpiece 1 is rotated 180 to reverse it (15). THc workpiece 1 is tHcn rotated again 90" in tHc reverse direction to return it to tHc floor conveyor position in an upright position (16). Thus, by controlling tHc workpiece position with a combination of vertical rotation and horizontal rotation, it is possible to realize horizontal painting in which each surface to be painted is always kept face upward for spray painting and a satisfactory finish coating can be realized. FurtHcr, tHc workpiece 1 is always kept at a remote position laterally from tHc conveyor 2. It is tHcrefore possible to remarkably reduce tHc possibility of dust and tHc like falling from tHc conveyor 2 to adHcre to tHc workpiece 1, so that tHc coating quality in tHc finish coating can be improved. In tHc finish drying process F tHcreafter, tHc workpiece 1 is maintained in tHc floor conveyor position to allow it to pass through tHc finish drying furnace (17). Fig, 2 is a side view showing a supporting condition of tHc workpiece I in tHc floor conveyor position and Fig. 3 is a plan view tHcreof. Fig. 4 is a front view of tHc workpiece 1 seen from tHc direction of travel F. As shown in tHcse figures, tHc carrier 3 is moveably supported in tHc longitudinal direction on one side of tHc conveyor 2 and a rotational shaft 4 extending substantially in a level plane laterally from tHc carrier 3 is rotatable 360" around its axis. One end of a vertical arm 5 is connected to one end of tHc rotational shaft 4 substantially at right angles and tHc otHcr end of tHc vertical arm 5 supports a center lower portion lb of tHc workpiece 1. A front part la of tHc workpiece 1 is fixedly secured to an end of an auxiliary stay 6 bent and extending from tHc vertical arm 5. With this construction, tHc workpiece 1 is situated laterally away from tHc carrier 3 and tHc conveyor 2. THc workpiece 1 is supported in an upright position, i.e. in tHc condition in which a motorcycle is used, within a plane parallel to tHc direction of travel F and parallel to tHc direction perpendicular to tHc direction of travel F (Hcreinafter referred to as "a vertical plane"). THc workpiece 1 is arranged to be rotatable by tHc rotational shaft 4 within tHc same vertical plane. THc vertical arm 5 is moveably arranged between an upright position suhstantialfy at right angles to tHc rotational shaft 4 and a position in a level plane substantially parallel to tHc rotational shaft 4. Thus, tHc workpiece 1 is moveable within anotHcr plane (Hcreinafter referred to as "a horizontal plane") perpendicular to tHc vertical plane and substantially parallel to tHc rotational shaft 4 and a vertical line. In addition, wHcn tHc workpiece 1 is rotated substantially 90" from tHc upright condition, tHc workpiece reacHcs tHc side conveyor position substantially in a level plane (see a virtual line condition of Fig. 4). A position control mechanism is provided to control tHcse workpiece positions, wHcrein tHcre is a vertical rotation mechanism and a horizontal rotation mechanism. Fig. 5 is a cross sectional view of basic parts for explaining tHc vertical rotation mechanism and Fig. 6 is a view of tHc vertical rotation mechanism in tHc direction of tHc rotational shaft 4. in tHcse figures, tHc conveyor 2 is a guide rail of a substantially C-shaped cross section in which a pair of rollers 7 is housed, one roller above tHc otHcr. Each roller is connected to tHc otHcr by a roller shaft 8 and adapted to travel in tHc longitudinal direction of tHc conveyor 2 by a driving means (not shown) such as a cable which is housed throughout tHc length of tHc conveyor 2. Four rollers are provided in two locations before and after tHc carrier 3, above and below relative to tHc one carrier 3. THc rollers are supported on a connecting portion 10 of tHc carrier 3 projecting inside conveyor 2 through a slit 9 continuously formed in tHc longitudinal direction in tHc side of tHc conveyor 2 facing tHc carrier 3. THc carrier 3 is a box-like member with its long side extending to tHc front and rear. THc rotational shaft 4 passes through tHc central portion of tHc carrier 3 and is rotatably supported by bearings 11 at locations wHcre it crosses tHc carrier 3. THc rotational shaft 4 within tHc carrier 3 is integrally provided with a pinion 12 around tHc middle portion between tHc right and left bearings 11 which engages a rack 13 arranged at tHc lower part of tHc carrier 3. THc rack 13 is disposed parallel to tHc conveyor 2 and fixedly secured to tHc conveyor 2 and tHc like. THc rack 13 also fits into a groove 14 passing through a bottom portion of tHc carrier 3 in tHc front and rear direction. WHcn tHc carrier 3 travels in a condition wHcre tHc pinion 12 has engaged tHc rack 13, tHc pinion 12 rotates. As a result, tHc rotational shaft 4 integrally formed with tHc pinion 12 rotates and tHc vertical arm 5 integrally formed with tHc rotational shaft 4 rotates, tHcreby vertically rotating tHc workpiece 1 which is supported by tHc vertical arm 5. THc angle of rotation of tHc workpiece 1 corresponds to that of tHc pinion 12, which relates to tHc distance that tHc pinion 12 and tHc rack 13 travel upon tHcir engagement. THc rack 13 may be continuously provided over tHc length of tHc conveyor 2 or may be provided at suitable intervals for each length corresponding to a rotation angle required for each location necessary to rotate tHc rotational shaft 4. WHcn tHc rack 13 is continuously provided throughout tHc length of tHc conveyor 2, tHc workpiece 1 moves while continuously undergoing vertical rotation and tHcrefore each process is adapted to agree with tHc cycle of this vertical rotation. On tHc contrary, wHcn tHc rack 13 is intermittently provided at any optional locations, tHc workpiece 1 can be vertically rotated only in tHc necessary processes according to tHc continuing processes. If tHcre is any process in which tHc vertical rotation of tHc workpiece 1 is not required, tHc rack 13 is not required to release tHc pinion 12. However, in this case, to maintain a predetermined workpiece position, it is necessary to control tHc rotation of tHc rotational shaft 4. For example, tHc rotation can be controlled by suitable control means such as a brake 15 that is provided within tHc " carrier 3. Fig. 7 shows tHc horizontal rotation mechanism in which tHc ends of tHc rotational shaft 4 and tHc vertical arm 5 are interconnected by a shaft 16 so as to allow tHc vertical arm 5 to stand upright or be positioned in a level plane. THc end of tHc vertical arm 5 is integrally provided with a projection 17 extending tHcrefrom and tHc projecting end of tHc projection 17 is connected to an end of a control rod 18 provided substantially parallel to tHc rotational shaft 4 by a shaft 19. THc otHcr end of tHc control rod 18 is not shown Hcre, but is connected to a control member provided within tHc carrier 3, WHcn tHc control rod 18 is pusHcd by tHc control member to tHc right-hand side of tHc figure (in tHc direction of tHc arrow a), tHc vertical arm 5 is caused to stand upright (Fig. 7A) so as to allow tHc workpiece 1 to stand upright. On tHc contrary, wHcn tHc control rod 18 is pulled to tHc left-hand side of tHc figure (in tHc direction of tHc arrow b), tHc vertical arm 5 is caused to be positioned in a level plane (Fig. 7B). THc workpiece 1 is tHcn caused to realize tHc side conveyor position (see Fig. 4). THc workpiece position wHcn tHc workpiece 1 is vertically rotated into tHc electrodeposition coating C will now be explained Hcreunder. In this process, as shown on an enlarged scale in Fig. 8, tHc workpiece 1 is maintained in tHc floor conveyor position in a draining process that is tHc last process of tHc pretreatment B. WHcn tHc workpiece 1 is tHcn subject to tHc electrodeposition coating C, tHc front part of tHc workpiece 1 starts to submerge in an electrodeposition paint bath 20 while vertically rotating and tHcn completely submerge in tHc electrodeposition paint bath 20 in tHc overHcad conveyor position. Within tHc electrodeposition paint bath 20, tHc workpiece 1 continues to rotate vertically and its front part begins to emerge from tHc liquid surface. After tHc workpiece 1 has completely emerged from tHc liquid surface, it returns to its original floor conveyor position and tHc dipping process is completed. THc workpiece 1 still continues to rotate vertically and reacHcs tHc floor conveyor position, tHc overHcad conveyor position and tHc floor conveyor position in turn to complete tHc washing process. Circled numerals in tHc figure correspond to tHc process numbers of Fig. 1. WHcn tHc workpiece 1 is vertically rotated within tHc electrodeposition bath 20, it is possible to perform tHc electrodeposition coating satisfactorily and efficiently. Since at least a part of tHc workpiece 1 is dipped in almost of this process, tHc proportion of loss of time not relating to dipping but required only for moving tHc workpiece 1 into and removing it from tHc bath, relative to tHc substantial dipping time, can be reduced, tHcrefore tHc electrodeposition time can also be reduced. Also, wHcn tHc workpiece 1 is removed from tHc electrodeposition bath 20, it emerges at a constant speed, front part first. It is tHcrefore possible to allow tHc excess paint to run " off and at tHc same time to realize uniform painting. Thus, even wHcn in a single treatment, it is necessary to move tHc workpiece to tHc floor conveyor position and to tHc overHcad conveyor position, it is no longer necessary to transfer tHc carrier 3 to tHc floor conveyor or tHc overHcad conveyor each time. Since tHc workpiece positions can also be continuously changed keeping tHc conveyor 2 in a fixed state, it is possible to considerably reduce tHc time required for changing tHc workpiece positions. Next, a second embodiment in which a part of tHc conveyor 2 is moveable to allow horizontal rotation will be explained. Figs. 9 to 12 relate to tHc second embodiment, in which Fig. 9 is a side view showing a part of tHc conveyor 2 cut away and Fig. 10 is a plan view tHcreof. Fig. 11 is a cross sectional view taken along tHc line 11 - 11 of Fig. 9. Fig. 12 is tHc same view as Fig. 11 showing a rotating condition. In tHcse figures, tHc conveyor 2 is a hollow member of substantially square cross section. A position for use in a process in which tlie worltpiece is necessary to be changed from tHc floor conveyor position to tHc overHcad conveyor position and tHc like at a part of tHc conveyor 2 is a separate moveable portion 30. This moveable portion 30 has tHc same cross section as tHc front and rear of tHc conveyor 2 and is arranged to be horizontally rotatable in a plane perpendicular to tHc direction of travel F of tHc conveyor 2. Namely, tHc moveable portion 30 is positioned between tHc front and rear at tHc conveyor 2, and a step motor 31 is fixedly secured to tHc inside of one side of tHc conveyor 2. THc rotational shaft 32 of tHc step motor 31 is provided parallel to tHc center of tHc conveyor 2 and tHc moveable portion 30 and arranged to penetrate vertical walls 33 provided before and after tHc moveable portion 30. THc rotational shaft 32 engages tHc vertical walls 33 to integrally rotate with tHcm. An end of tHc rotational shaft 32 is fixedly secured to a vertical wall 34 of tHc otHcr side of tHc conveyor 2 by a nut 35. With this construction, wHcn tHc step motor 31 rotates by a predetermined amount, tHc moveable portion 30 integrally connected to tHc rotational shaft 32 integrally rotates horizontally to an angle corresponding to tHc amount of rotation of tHc step motor 31, THc bottom surface of tHc conveyor 2 is supported on a floor by support pillars 36 which are provided at fixed intervals in tHc longitudinal direction. THc moveable portion 30 is not provided with tHc support pillars 36 so as to be rotatable. THc carrier 3 has a main body portion 37 of a square hole shape which is slightly larger than tHc conveyor 2 and tHc moveable portion 30. THc main body portion 37 is formed to have similar figures with tHc conveyor 2 and tHc moveable portion 30. Since tHc conveyor 2 and tHc moveable portion 30 can pass through tHc inside of tHc main body portion 37, tHc carrier 3 is guided along tHc conveyor 2 and tHc moveable portion 30 to be moveable in tHc direction of travel like a monorail-One end of a supporting rod 38 is integrally provided on tHc upper surface of tHc main body portion 37 and tHc workpiece 1 is supported by tHc otHcr end of tHc supporting rod 38. Rollers 39 are rotatahly supported in a total of four places, front and back and right and left of each surface, and arranged to roll on each surface of tHc conveyor 2 and tHc moveable portion 30. Circular plate-shaped flanges 40 are provided at tHc front and rear ends of tHc main body portion 37. A part of each flange 40 that becomes tHc lower part wHcn in tHc floor conveyor position is formed with a cut out portion 41 to avoid interference by tHc support pillars 36 during travel. THc flange 40 always engages a substantially C-shaped engaging member 42 and tHc engaged condition is maintained even though tHc carrier 3 rotates horizontally. THc engaging member 42 is fixedly secured to a belt-shaped conveyance-driving member 43 which is arranged parallel to tHc conveyor 2. As tHc conveyance-driving member 43 moves in tHc direction of travel F, tHc engaging member 42 also moves in tHc direction of travel F on eitHcr tHc conveyor 2 or tHc moveable portion 30 irrespective of tHc horizontal rotation of tHc carrier 3. An operation of tHc present embodiment will now be described. Fig. 13 shows tHc electrodeposition coating process C in which tHc carrier 3 moves on tHc conveyor 2 in tHc floor conveyor position. Once tHc carrier 3 reacHcs tHc moveable portion 30 of tHc conveyor 2 provided above tHc electrodeposition paint bath 20, it stops moving. Next, wHcn tHc step motor 31 is rotated 180 , tHc carrier 3 also rotates horizontally 180" through tHc vertical wall 33 integrally provided with tHc rotational shaft 32. Thus, tHc workpiece 1 rotates horizontally to tHc overHcad conveyor position and tHc tike and is tHcn inserted into tHc electrodeposition paint bath 20. After tHc paint adHcres to tHc workpiece 1 in tHc dipping process, tHc workpiece 1 is rotated 180" , emerges from tHc electrodeposition paint bath 20 and returns to tHc original floor conveyor position. In this case, by setting tHc step motor 31, it is possible to eitHcr allow tHc workpiece 1 to continuously rotate horizontally or to allow it to rotate intermittently within tHc electrodeposition paint bath 20. It is tHcrefore possible to realize satisfactory electrodeposition painting by allowing tHc workpiece 1 to move within tHc electrodeposition paint bath 20. FurtHcr, since tHc conveyor 2 does not move vertically, but is linearly maintained in tHc same horizontal plane, it is possible to immediately insert tHc workpiece 1 into tHc dipping process. As a result, tHc time lost wHcn tHc dipping is not substantially performed, i.e. wHcn tHc workpiece 1 is inserted into and removed from tHc electrodeposition paint bath 20, can be remarkably reduced, and tHc total painting time can be reduced. Still furtHcr, tHc workpiece 1 can be horizontally rotated to change tHc workpiece position to tHc floor conveyor position and to tHc overHcad conveyor position, and tHc like. Accordingly, even wHcn tHc workpiece position must be changed for each subsequent process (e.g. 13 to 15), it is no longer necessary to transfer tHc workpiece 1, and loss of time can be reduced. It is particularly suitable for a tact treatment in which conveyance is temporarily stopped for each process {e.g. 13 to 15) for necessary treatment. Since a part of tHc conveyor 2 itself is arranged to serve as tHc moveable portion 4, it is possible to strengtHcn tHc moveable portion 4 and simplify tHc construction comparatively. Also, tHc rotational means can be easily provided by tHc step motor 5 and wHcn tHc step motor 5 is used, it can be easily housed in tHc hollow portion of tHc conveyor 2 wHcreby tHc rotational direction and angle tHcreof can be freely controlled. Since tHc carrier 3 is supported on tHc conveyor 2 like a monorail, tHc supporting construction for tHc carrier 3 is simplified and strengtHcned and it is possible to stabilize tHc conveyance of tHc workpiece 1. It is especially suitable wHcn a Hcavy workpiece 1 is supported. FurtHcr, tHc carrier 3 is provided with flanges 14 that engage tHc engaging member 16 of tHc carrier feeding member 17 provided parallel to tHc conveyor 2. Even if tHc carrier 3 rotates, engagement of tHc flanges 14 with tHc engaging member 16 is maintained to allow tHc carrier 3 to move. It is tHcrefore suitable for a mechanism capable of moving tHc carrier 3 irrespective of tHc rotational position of tHc carrier 3. Next, a third embodiment regarding tHc same horizontal rotation mechanism as above will be described. Fig. 14 is a side view of tHc moveable portion of tHc conveyor partially cut away and Fig. 15 is a plan view showing tHc operation tHcreof. Fig. 16 is a view showing tHc operation of tHc horizontal rotation mechanism from tHc direction of travel F and from tHc front, respectively. In tHcse figures, tHc conveyor 2 is formed in a hollow box shape and provided in one part with a moveable portion 30. THc moveable portion 30 is situated between two sides of tHc conveyor 2 and is rotated by a step motor 31 which is fixedly secured to tHc inside of one side of tHc conveyor 2. A rotational shaft 32 of tHc step motor 31 passes through a vertical wall 33 of tHc moveable portion 30 and extended to tHc otHcr side of tHc conveyor 2. One end of tHc rotational shaft 32 is fixedly secured to a vertical wall 34 provided on tHc otHcr side of tHc conveyor 2. THc moveable portion 30 rotates synchronously with tHc rotational shaft 32 wHcn tHc vertical walls 33 and tHc rotational shaft 32 are integrally rotated. THc carrier 3 is so connected as to move along each side of tHc conveyor 2 and tHc moveable portion 30. A projection 10 of tHc carrier 3 projects to tHc inside of tHc conveyor 2 and tHc moveable portion 30 through slits 9 continuously formed in each side tHcreof in tHc longitudinal direction. THc projection 10 supports rollers 11 that are provided at four-corners, back and front and upper and lower. THc carrier 3 can be moved by tHc rollers 11 which roll on tHc inside of tHc conveyor 2 and tHc moveable portion 30 and is moved in tHc direction of travel by suitable driving means not shown Hcre. As is obvious from Figs. 15 and 16, a horizontal arm 50 extends laterally from one side of tHc carrier 3, and one end of tHc arm 50 supports tHc workpiece 1 such as a motorcycle in a suitable condition (see Fig. 16A). As shown in Fig. 15 A, tHc workpiece 1 is supported on one side of tHc conveyor 2 and tHc moveable portion 30 (on tHc left side in tHc present embodiment). An operation of tHc present embodiment will now be described. WHcn tHc carrier 3 moves above tHc electrodeposition paint bath 20 of Fig. 16, it stops moving and tHc step motor 31 rotates 180 " . As a result, tHc moveable portion 30 rotates horizontally to tHc overHcad conveyor position and tHc like as shown in Fig. 16B, wHcrein tHc same dipping process as for tHc previous embodiment can Hc performed. Since tHc dipping process is tHc same as tHc previous embodiment, furtHcr description is omitted. Thus, if tHc carrier 3 is formed in a type wHcre it is supported on one side of tHc conveyor 2, tHc workpiece 1 can be supported laterally away from tHc conveyor 2. THcrefore, substances such as dust or tHc like falling from tHc conveyance 2 are prevented from adHcring to tHc workpiece 1.. Accordingly, this type of a conveyance apparatus is suitable for a painting line in which adHcsion of dirt is particularly undesirable. Fig.l is a flow chart of a complete painting line adopted tHc horizontal rotation mechanism as described in tHc embodiment 2 and 3, which corresponding to Fig. 1. THc preferred embodiments that have been applied to a painting line for a motorcycle will be described Hcreunder. In tHc painting line of Fig. 18, each process of loading and jig attachment A, pretreatment B, electrodeposition coating C, electro-deposition drying D, finish coating E and finish drying F is continuously performed in sequence. Encircled figures in tHc flow chart show tHc processes of Fig. 18. (THc number of tHc process in tHc description is shown by tHc corresponding parentHcsized figures.) In tHc process of loading and jig attachment A, a workpiece 1 which is tHc body of a motorcycle has been hung and conveyed by an overHcad conveyor HC of a welding line which is a process previous to this painting line. THc workpiece 1 is tHcn supported on a conveyor 2 through a carrier 3 in a floor conveyor position (1). Now, in tHc process of pretreatment B, tHc workpiece 1 is horizontally rotated to change its position continuously to tHc floor conveyor position and to an overHcad conveyor position, wHcrein each process of degreasing (2) (tHc overHcad conveyor position), washing and surface preparation (3) (tHc floor conveyor position), cHcmical conversion treatment (4) (tHc overHcad conveyor position), washing (5) (tHc floor conveyor position), washing (6) (tHc overHcad conveyor position), and pure water washing and draining (7) (tHc floor conveyor position) is performed. In tHc process of electrodeposition coating C, tHc workpiece 1 is likewise ." rotated horizontally to change its position continuously to tHc floor conveyor position and to tHc overHcad conveyor position, wHcrein each process of tHc electrodeposition coating (8) (tHc overHcad conveyor position), washing (9) (tHc floor conveyor position), washing (10) (tHc overHcad conveyor position) and pure water washing (11) (tHc floor conveyor position) is performed. In tHc process of pretreatment drying D, tHc workpiece 1 is passed through an electrodeposition-drying furnace while maintaining tHc floor conveyor position without changing tHc workpiece position (12). In finish coating E, tHc workpiece 1 is conveyed into a finish-coating booth of a spray type. At tHc moveable portion provided on tHc conveyor 2, if tHc workpiece 1 is moved while horizontally rotating 90" each time around a shaft of tHc conveyor 2, each process of bottom painting in tHc overHcad conveyor position (13), side painting in tHc side conveyor position (14), opposite side painting in tHc side conveyor position (15) and top painting in tHc floor conveyor position (16) is performed in sequence, wHcrein each surface not to be painted is always kept face upward for tHc best results. Next, a fourth embodiment, in which a pair of upper and lower travelling rail is provided in a similar painting line will be described below with reference to tHc accompanying drawings. Fig. 19 is a side view for explaining tHc structure of tHc present conveyance apparatus. Fig. 20 is a front view of Fig. 19 and Fig. 21 is an explanatory view of a driving source of a carrier inversion mechanism. Fig. 22 is a view explaining tHc relationship between tHc carrier and tHc conveying stand in tHc case of a single rail. THc conveyance apparatus according to tHc present invention is, for example, applied to a conveyance apparatus which is intended to handle a workpiece requiring electrodeposition painting and a workpiece not requiring tHc electrodeposition painting on a common line, in a manufacturing process for a fuel tank, a frame body or tHc like, as parts for a motorcycle. This intends to simplify tHc apparatus, to reduce tHc equipment costs, and also can eliminate tHc necessity for complicated conveying control. As shown in Fig. 19, a workpiece conveying path 102 is provided above an electrodeposition bath 101 as a treatment bath. Along this workpiece conveying path 102, both a workpiece Wl which undergoes electrodeposition painting and a workpiece W2 which does not undergo electrodeposition painting are arranged to be conveyable by means of a carrier 104. For this purpose, carrier inversion mechanisms 103a, 103b are provided in tHc workpiece conveying path 102 above tHc electrodeposition bath 101 to position an intermediate travelling portion 105 of tHc intermediate portion of tHc path between tHc upstream and downstream sides of tHc electrodeposition bath. THc position of tHc workpiece Wl which undergoes electrodeposition painting is invertedl80o , as shown in Fig. 19(b), by means of tHc inversion mechanism on tHc upstream side to pass tHc intermediate travelling portion 105. After being switcHcd to a course by which tHc workpiece Wl travels through tHc electrodeposition bath 101, tHc workpiece Wl is inverted to its original position by means of tHc carrier inversion mechanism 103b on tHc downstream side. THc workpiece W2 which does not undergo electrodeposition painting is caused to pass tHc carrier inversion mechanism 103a, 103b area without changing tHc position, as shown in Fig. 19(a), and to have a course passing above tHc electrodeposition bath 101. THc workpiece conveying path 102 is provided with travelling rails 107 mounted on both sides of a rail support 106. Rail supports 106, 106a, 106b of tHc workpiece conveying path 102 above tHc electrodeposition bath 101 are provided with at least a pair of upper and lower travelling rails 107x, 107y. THc carrier inversion mechanism 103a, 103b is arranged so that respective rail supports 106a, 106b can be inverted. As shown in Fig. 21, an inversion motor 108 is fixedly secured to tHc rail support 106 of tHc fixed side adjacent to tHc carrier inversion mechanisms 103a, 103b. A drive shaft of this inversion motor 108 is secured to tHc center of tHc rail supports 106a, 106b of each carrier inversion mechanism 103a, 103b. Each of rail supports 106a, 106b is adapted to be rotatable 180 by tHc inversion motor 108 in a plane crossing at right angles to tHc conveying path. In addition, tHc pair of travelling rails 107x, lD7y of tHc rail supports 106a. 106b which can freely invert are symmetrically positioned above and below relative to tHc center of tHc drive shaft of tHc inversion motor 108. For example, before inverting, wHcn tHc travelling rail 107x above tHc carrier inversion mechanism 103a, 103b coincides with tHc line of tHc travelling rail 107x above tHc intermediate travelling portion 105, tHc travelling rail 107x of tHc carrier inversion mechanism 103a, 103b after inverting, is adapted to coincide with a line of tHc travelling rail 107 below tHc intermediate travelling portion 105. THc carrier 104, as shown in Fig. 20, is provided with a sliding portion 104s which slidably engages tHc left and right travelling rails 107, a gate-shaped portion 104m which projects outwardly in a shape to straddle tHc rail support 106, and a workpiece holding portion 104h which is projectingly provided at tHc center of tHc gate-shaped portion 104m. THc workpieces Wl, W2 can be retained by this workpiece holding portion 104h. A conveying stand 109 of tHc rail support 106 at at least tHc intermediate travelling portion 105 of tHc workpiece conveying path 102, as shown in Fig. 20, is provided standing upright on a floor surface and is intended to support tHc intermediate portions of tHc upper and lower travelling rails 107x, 107y. THc carrier 104 and tHc conveying stand 109 are designed not to interfere with one anotHcr, wHctHcr tHc workpiece is supported by tHc upper carrier 104 or tHc lower carrier 104. Specifically, in order that tHc carrier 104 and tHc conveying stand 109 do not interfere with one anotHcr, in tHc case wHcre tHc carrier 104 and tHc workpiece Wl are inverted by means of tHc carrier inversion mechanism 103a, and in tHc case wHcre tHc carrier 104 and tHc workpiece W2 pass in tHc non-inverted state, tHc workpiece conveying path 102 at at least tHc upper portion of tHc electrodeposition bath 101 is formed with double, upper and lower, travelling rails 107x, 107y If only one rail is used, as shown in Fig. 22, in a position {Fig. 22(a)) of tHc conveying stand 109, wHcre tHc carrier 104 is placed above tHc drive shaft of tHc inversion motor 108, if tHc carrier 104 is inverted downwardly togetHcr with tHc rail support 106, tHc carrier 104 and tHc conveying stand 109 will interfere with one anotHcr. In addition, a position (Fig. 22(b)) of tHc conveying stand 109, wHcre tHc carrier 104 is placed below tHc drive shaft of tHc inversion motor 108, if tHc carrier 104 is inverted upwardly togetHcr with tHc rail support 106, tHc carrier 104 and a supporting portion 109a of tHc conveying stand 109 will interfere with one anotHcr. THcrefore, tHcre is some possibility that in tHc case of one rail, conveyance can not be performed depending on tHc positions of tHc carrier 104 and tHc workpiece. THc double, upper and lower, rail structure is tHcrefore employed in tHc present invention so that conveyance can be performed irrespective of tHcse positions. An operation of tHc above-mentioned conveyance apparatus will be described. As shown in Fig. 19, wHcn tHc workpiece retained by tHc carrier 104 is transferred from tHc left side of Fig. 19 along tHc travelling rail 107 up to tHc carrier inversion mechanism 103a on tHc upstream side, if this is tHc workpiece to Hc immersed in tHc electrodeposition bath 101 for painting, as shown in Fig. 19(b), tHc diversion motor 108 of tHc carrier inversion mechanism 103a is actuated to invert tHc rail support 106a 180" . As a result, tHc position of tHc carrier 104 and tHc workpiece Wl is also inverted 180" , and tHc workpiece is immersed in tHc electrodeposition bath 101, tHcn, tHc upper travelling rail 107x on which tHc carrier 104 has traveled up to that time contacts tHc lower travelling rail 107y of tHc intermediate travelling portion 105. WHcn tHc carrier 104 travels tHc lower travelling rail 107y of tHc intermediate traveUing portion 105 and reacHcs tHc carrier inversion mechanism 103b at tHc downstream side, this drive motor 108 is actuated to invert tHc workpiece togetHcr with tHc rail support 6a, wHcreby tHc workpiece is pulled from tHc electrodeposition bath 101 to return to its original position, tHcn conveyed downstream. Next, in case of tHc workpiece W2 which does not undergo tHc electrodeposition painting, as shown in Fig. 19(a), wHcn tHc workpiece W2 retained by tHc carrier 104 is transferred from tHc left side of tHc figure along tHc traveUing rail 107 up to tHc carrier inversion mechanism l03a on tHc upstream aide, tHc original position is maintained and tHc carrier 104 travels along tHc upper travelling rail 107x of tHc intermediate travelling portion 105 and is transferred via tHc carrier inversion mechanism 103b as is. That is, tHc workpiece W2 passes without being immersed in tHc electrode position bath 101. As outlined above, it is possible to transfer both tHc workpiece Wl which is immersed in tHc electrodeposition bath 101 and tHc workpiece W2 which is not immersed in tHc electrodeposition bath 101, and it is unnecessary to implement complicated transferring control as in a by-pass line of tHc prior art. It is also possible to avoid extending tHc conveying path. A fifth embodiment of tHc present invention will be now described with reference to tHc accompanying drawings. Fig. 24 is an explanatory view of a conveyance apparatus using a conveyance path lifter mechanism. Figs. 25 and 26 are explanatory views of a conveyance apparatus using a conveying path reversing mechanism. According to tHc conveyance apparatus of tHc present invention, in an assembly line for vehicles, pretreatment such as electrodeposition is applied to vehicle body parts and tHc conveyance apparatus is constructed to feed tHcse parts to tHc drying process, wHcrein tHc space for installing tHc equipment is minimized and investment for tHc equipment can also be reduced. THc workpiece conveyance path in tHc form of travelling rails or tHc like is provided between tHc pretreatment process such as an electrodeposition painting and tHc drying process. A series of operation from painting to drying can be continuously carried out by allowing tHc workpiece to move along tHc workpiece conveyance path. THc workpiece conveyance path for tHc drying process is installed at a higHcr level than tHc workpiece conveyance path for tHc pretreatment process to prevent hot air of, for example, about 140°C - 160oC in tHc drying process from entering tHc pretreatment process in which a normal temperature of about 25oC is to be maintained. Thus, tHc hot air which tends to remain at tHc high level is controlled not to affect tHc workpiece conveyance path for tHc pretreatment process. In addition, according to tHc present invention, in a drying equipment in which tHc Hcight of a workpiece conveyance path for a pretreatment process and tHc Hcight for a workpiece conveyance path for a drying process differ, a connecting workpiece conveyance path is provided with a conveyance path lifter mechanism or a conveyance path reversing mechanism so that tHc distance between tHc pretreatment process and tHc drying process can be shortened and tHc space for equipment, can be minimized. A construction example with tHc conveyance path lifter mechanism will be described with reference to Fig. 24. As shown in Fig. 24, in a pretreatment process A in which, for example, an electrodeposition bath or tHc like is arranged, a workpiece conveyance path Ha is provided, which allows a workpiece W transported by a carrier G to be immersed in an electrodeposition bath (not shown). THc workpiece W is supported by tHc carrier G. A workpiece conveyance path Hc for a drying process C is arranged and provided at a higHcr level than tHc workpiece conveyance path Ha for tHc pretreatment process to prevent hot air, which tends to remain at tHc higHcr level, from entering tHc pretreatment process A. A connecting workpiece conveyance path Hb which is situated between tHc drying process C and tHc pretreatment process A is provided on a rail supporting elevator X. This rail supporting elevator X is arranged to move up and down by tHc conveyance path lifter mechanism. This conveyance path lifter mechanism is provided with, for example, an elevator cylinder or tHc like (not shown) for moving up and down tHc rail supporting elevator X. At tHc downward position, tHc connecting workpiece conveyance path Hb and tHc workpiece conveyance path Ha of tHc pretreatment process A become interconnected, while at tHc upward position, tHc connecting workpiece conveyance path Hb and tHc workpiece conveyance path Hc of tHc drying process C become interconnected. In tHc conveyance apparatus described above, as shown in Fig. 24(a), wHcn tHc workpiece W which has been painted in tHc pretreatment process is transferred to tHc connecting workpiece conveyance path Hb by tHc carrier G, tHc rail supporting elevator X is caused to ascend togetHcr with tHc carrier G by means of tHc conveyance path lifter mechanism, and, as shown in Fig. 24(b), tHc connecting workpiece conveyance path Hb is connected to tHc workpiece conveyance path Hc of tHc drying process C. In addition, tHc carrier G proceeds to tHc drying process C and tHc workpiece W undergoes drying in a drying furnace or tHc like, wHcrein tHc distance between tHc pretreatment process A and tHc drying process C can be minimized. Thus, it is possible to reduce equipment costs and save space. Next, an example of a structure in tHc case wHcre a connecting workpiece conveyance path can be freely reversed by means of a conveyance path reversing mechanism is described with reference to Figs. 25 and 26. In this example, a conveyance path reversing mechanism is provided at an intermediate portion of a pretreatment process A and a drying process C. This conveyance path reversing mechanism, for example, as shown in Fig. 25, is so designed that a rail supporting and reversing body Y is freely rotated about a central axis parallel to tHc conveying direction by means of a reversing motor M or tHc like. On this rail supporting and reversing body Y are provided pairs of upper and lower workpiece conveyance paths Hu, Hd, at tHc left and right sides, respectively. In addition, wHcn this rail supporting and reversing body Y is reversed 180° in a plane at right angles to tHc conveying direction, tHc lower workpiece conveyance path Hd connected to tHc workpiece conveyance path Ha for tHc pretreatment process A side becomes connected to tHc workpiece conveyance path Hc for tHc drying process C side. Also, tHc upper workpiece conveyance path Hu connected to tHc workpiece conveyance path Hc for tHc drying process C side becomes connected to tHc workpiece conveyance path Ha of tHc pretreatment process A side. In tHc conveyance apparatus as described above, as shown in Fig. 26(a), wHcn tHc workpiece W which has been painted in tHc pretreatment process A is transferred to tHc workpiece conveyance path Hd below tHc rail supporting and reversing body Y through tHc workpiece conveyance path Ha, tHc rail supporting and reversing body Y is reversed by 180" togetHcr with tHc carrier G by tHc conveyance path reversing mechanism, and, as shown in Fig. 26(b), tHc workpiece conveyance path Hd with which tHc carrier G engages is connected to tHc workpiece conveyance path Hc for tHc drying process C. In this manner, tHc positions of tHc carrier G and tHc workpiece W are reversed by 180 In addition, tHc carrier G is transferred to tHc drying process C and tHc workpiece W is dried tHcrein. In this case, also, because tHc distance between tHc pretreatment process A and tHc drying process C can be minimized, it is possible to reduce tHc equipment costs and save tHc space. THc invention is not limited to tHc embodiments as mentioned above. Those having substantially tHc same structure as described in tHc appended claims of tHc present invention and performing tHc same operation and effect are considered to fall within tHc technical scope of tHc present invention. For example, it is to be noted that tHc workpiece position control according to tHc present invention is not limited to a car body painting line, but can be applied, for example, to otHcr surface treatment lines. FurtHcr, as far as tHc continuous workpiece position control such as for an assembly line of a car body is required, tHc present invention can also be applied to various treatments. Also, tHc treatment bath may be a dipping bath otHcr than tHc electrodeposition bath, and tHc kind of workpiece may be optionally selected. It is to be noted that tHc carrier inversion mechanism 103a, I03b may not necessarily be provided at two locations. It may be provided at only one location, wHcreby after tHc workpiece is inverted and immersed in tHc treatment bath, it may again be inverted to return to its original position and furtHcr transferred. Also, concrete structures or tHc like for driving means of tHc conveyance path lifter mechanism and for tHc conveyance path reversing mechanism may be optionally selected. WE CLAIM: 1. A conveyance apparatus having a conveyor for supporting a workpiece and adapted to allow the workpiece to pass thorough a plurality of treating processes while changing a workpiece position, wherein a position control mechanism for changing the workpiece position is provided so that the workpiece position required for each treating process can be continually changed without transfer of the workpiece, wherein the position control mechanism provides a floor conveyor position which supports the workpiece above the conveyor and an overhead conveyor position which hangs and supports the workpiece below the conveyor. 2. The conveyance apparatus according to claim 1, wherein the rotational means is a step motor that is disposed within the conveyor. 3. The conveyance apparatus according to claim 1, wherem a change in the workpiece position is a vertical rotation that is made within a plane parallel to the direction of travel of the conveyor. 4. The conveyance apparatus according to claim 1, wherein the position control mechanism is provided with a rotational shaft which projects laterally from the conveyor and the workpiece is secured to one end of the rotational shaft so as to be rotatable around its axis. 5. The conveyance apparatus according to claim 1, wherein the position control mechanism is provided with an arm member which rocks in a plane perpendicular to the direction of travel of the workpiece so as to cause horizontal rotation of the workpiece. 6. The conveyance apparatus according to claim 5, wherein the position control mechanism enables the horizontal rotation to provide a side conveyor position at which the workpiece is supported substantially in a level plane on the side of the conveyor by rocking the arm member within a horizontal plane. 7. The conveyance apparatus according to claim 1, wherein the position mechanism makes vertical rotation possible by arranging the rotational shaft projecting laterally from the conveyor to support the workpiece and rotating the shaft around its axis, and horizontal rotation possible by rocking the arm member within the horizontal plane and continuously controls the rotation of the workpiece to the floor conveyor position, the overhead conveyor position, and a side conveyor position by combining the vertical rotation and the horizontal rotation. 8. The conveyance apparatus according to claim 1, wherein the carrier is supported on one side of the conveyor and conveyed in the direction of travel. 9. The conveyance apparatus according to claim 1, wherein the carrier is arranged to move like a monorail on the periphery of the conveyor which passes through the center portion of the carrier. 10. The conveyance apparatus according to claim 1, wherein a carrier feeding means for moving the carrier on the conveyor in the direction of travel is provided parallel to the conveyor and the carrier is provided with a flange portion which always engages the carrier feeding means. 11. A conveyance apparatus having a conveyor for supporting a workpiece through a carrier and adapted to allow the workpiece to pass through a plurality of treating processes while changing a workpiece position, wherein a part of the conveyor is arranged to serve as a moveable portion and a rotational means is provided to rotate the moveable portion in a plane at right angles to the direction of travel, wherein the rotational means rotates the moveable portion together with the carrier.

Documents:

0008-mas-2001 abstract-duplicate.pdf

0008-mas-2001 abstract.pdf

0008-mas-2001 claims-duplicate.pdf

0008-mas-2001 claims.pdf

0008-mas-2001 correspondence-others.pdf

0008-mas-2001 correspondence-po.pdf

0008-mas-2001 description (complete)-duplicate.pdf

0008-mas-2001 description (complete).pdf

0008-mas-2001 drawings-duplicate.pdf

0008-mas-2001 drawings.pdf

0008-mas-2001 form-1.pdf

0008-mas-2001 form-19.pdf

0008-mas-2001 form-26.pdf

0008-mas-2001 form-3.pdf

0008-mas-2001 form-5.pdf

0008-mas-2001 petition.pdf