Abstract:
Conveyor apparatus comprises an endless conveyor operative to convey workpieces past a number of processing stations. The workpieces are conveyed in seats of the conveyor, each of the seats being designated to receive a workpiece which is at a predetermined stage in the process. Means are provided to sense the presence of filled and empty seats and to control workpiece removal and depositing means associated with the processing stations so that workpieces are only removed from, and deposited in, the appropriate designated seats.

Description:
This is a continuation of application Ser. No. 851,754 filed Nov. 15, 1977, now abandoned. 
    
    
     BACKGROUND ON THE INVENTION 
     1. Field of the Invention 
     The present invention relates to conveyors. 
     2. Description of the Prior Art 
     There has been proposed conveyor apparatus for workpieces which are to undergo processing operations along the path of the apparatus, for example workpieces in the form of rotors of electrical machines which are to undergo winding and welding operations. 
     Such apparatus comprises an endless flexible member having a plurality of seats for the workpieces and a plurality of processing stations (such as winding and welding stations) along an active upper path of said conveyor. 
     An object of the invention is to provide an improved apparatus of this type. 
     SUMMARY OF THE INVENTION 
     According to the present invention, there is provided conveyor apparatus comprising means defining an active conveyor path passing adjacent a plurality of processing stations, means defining an endless conveyor movable along said path, said conveyor having means defining seats for workpieces to be conveyed along said path, means operative to feed workpieces to predetermined seats of the conveyor, means associated with the processing stations for removing workpieces from the seats for processing at the corresponding stations and to deposit the processed workpieces into the seats, said seats consisting of a plurality of groups of seats, in each said group of seats individual seats being designated to receive only workpieces which are at a predetermined stage in the process, detecting means for detecting the instantaneous condition of the conveyor and the locations of filled and empty seats in predetermined positions of the seats along the path, said detecting means controlling the operation of the workpiece removal and depositing means whereby the workpiece removal and depositing means only remove workpieces from, and deposit workpieces into, the designated seats, and means enabling any incompletely processed workpieces to be returned to the beginning of the active conveyor path. 
     Further according to the present invention, there is provided conveyor apparatus comprising means defining an endless conveyor path passing adjacent a plurality of processing stations means defining an endless conveyor movable along said path, said conveyor having means defining seats for workpieces to be conveyed along said path, means operative to feed workpieces to predetermined seats of the conveyor, means associated with the processing stations for removing workpieces from the seats for processing at the corresponding stations and to deposit the processed workpieces into the seats, said seats consisting of a plurality of groups of seats, in each said group of seats individual seats being designated to receive only workpieces which are at a predetermined stage in the process, and means sensing the prescence of filled and empty seats in specific positions of the conveyor, said sensing means controlling the workpiece removal and depositing means, whereby the workpiece removal and depositing means only remove workpieces from, and deposit workpieces into, the appropriate designated seats. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
     FIG. 1 is a side elevation of conveyor apparatus according to a first embodiment of the invention; 
     FIG. 2 is an enlarged view showing sensing means of the conveyor apparatus; 
     FIG. 3 is a view of the sensing means along line III--III of FIG. 2; 
     FIG. 4 is a fragmentary transverse section through the conveyor apparatus; 
     FIG. 5 shows schematically the conveyor apparatus and an associated working station; 
     FIG. 6 shows a modified form of conveyor for the apparatus of FIGS. 1 to 5; 
     FIGS. 7 and 8 are a schematic plan view and side elevation of another embodiment of conveyor apparatus in accordance with the invention; 
     FIGS. 9 and 10 are cross-sections, to an enlarged scale, showing an endless flexible conveyor and a carriage of the apparatus shown in FIGS. 7 and 8; and 
     FIGS. 11 and 12 are respectively, a vertical section and a section taken along line XII--XII of FIG. 11 showing a driving and control system of the apparatus as shown in FIGS. 7 and 8. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The conveyor apparatus shown in FIGS. 1 to 5 comprises a main frame 1 having guide means 3 (see FIG. 4) for an endless conveyor comprising two conveyor chains 5. The two chains 5 are driven in unison, the chains 5 being parallel and being suitably connected to each other. The chains are driven by means of a motor 6 which effects stepwise movement of the conveyor or continuous movement, with controls to stop and start the conveyor depending upon the condition of control means as will be described hereinafter. The conveyor chains 5 carry saddle shaped, i.e. V-shaped, seats 7, the seats 7 of the two chains being aligned to receive workpieces 9. These workpieces may be electric motor rotors which are to be subjected to various operations along the path of the conveyor, including winding of insulated wires and welding of the ends thereof to the commutators. The workpieces are fed to the conveyor by feed means 10. 
     Two successive winding stations 12 and 14 include winding machines of conventional type having means for picking-up the workpieces 9 from the seats 7 and for depositing the workpieces into the seats 7 after the winding operation. References 16 and 18 denote two successive welding stations including conventional welding machines also provided with pick-up and depositing means for the workpieces. Discharge means 20 are provided at the end of the conveyor to pick-up workpieces for delivery to further processing stations or for delivery to further conveyors. 
     The conveyor has means for retaining certain workpieces which are to be moved along the lower run of the conveyor in a direction f 2  opposite to the advance direction f 1  of the upper run for reasons which will be explained hereinafter. These means may be constituted by profiles 22 extending along the whole of the lower run, from the discharge means 20 to the feed means 10. 
     When the apparatus is being used for the manufacture of electric motor rotors (as described) the following are present on the conveyor--workpieces in an unwound state, wound workpieces still to be welded, and wound and welded workpieces. For this purpose, the conveyor has groups of three seats 7, in each of which the respective seats are designated to receive, respectively, the unwound workpieces, the wound and unwelded workpieces, and the wound and welded workpieces. In particular, in a group of three successive seats, one seat designated O is intended to receive an unwound workpiece, a second seat I is intended to receive a wound and unwelded workpiece, and a third seat II is intended to receive a wound and welded workpiece. Successive groups of said seats follow each other along the conveyor, whose seats are therefore arranged in groups of three, designated O, I, and II. In order to designate the different seats, suitable marks may be provided on the same seats so that they can be recognized by sensor means, such as microswitches or the like, or selection means may be provided which are linked to the transmission means of the chain conveyor. In this latter case, as shown in FIGS. 2 and 3, on a shaft 24 which carries driving sprockets of the transmission means, there is provided a group of three cams 26, 28, 30 which are associated with three microswitches 32, 34 and 36. The cams 26, 28, 30 and the seats on the chain are positionally synchronized so that the position of the seats O, I, II of the successive groups is determined and set for the whole path by the position of the shaft 24, and thus of the cams, in any standstill position of the conveyor. At each of the stations 12, 14, 16 and 18 sensing means are provided to detect the presence or absence of a workpiece on a given seat positioned with respect to the corresponding group. Such sensing means may be microswitches 38, 40, 42, and 44, which detect the presence of a workpiece or the empty seat in the desired position at which the picking-up or the depositing of the workpiece must be accomplished in the respective group. 
     The unwound and unwelded workpieces from the feed means 10, are deposited in the seats which are designated O. The workpieces on the seats designated O can be picked-up for the winding operation at either of the stations 12 and 14, at which their presence is detected by the sensing means 38 and 40. At the stations 12 and 14 the then wound but unwelded workpieces are deposited into empty seats designated I which are also detected by the sensing means 38 and 40. At the stations 16 and 18, the sensing means 42 and 44 detect the presence of the workpieces in the seats designated I so that these workpieces are picked up for the welding operation; the then wound and unwelded workpieces are deposited into empty ones of the seats designated II and which are presented before the depositing position in the stations 16 and 18. 
     The selection among the O, I, and II seats and among occupied and empty seats is determined by the operative cooperation between the sensing means 32, 34, 36 and the sensing means 38, 40, 42, and 44, respectively. 
     Feeding and unloading of the conveyor can be controlled in response to means detecting the presence of empty seats O to operate the feed means 10, and means detecting the presence of occupied seats II to operate the discharge means 20. 
     The feed means 10 can accumulate workpieces ready for winding and welding so as to act as a storage unit between the conveyor and means upstream of the conveyor for the production or feeding of the workpieces. It may occur that certain workpieces are not wound, or welded at the stations 12, 14 or 16, 18, and these workpieces may be recycled along the lower run of the conveyor so that these workpieces can be presented again to the stations 12, 14 and 16, 18 until these workpieces are finished and deposited in the seats II and finally discharged. If more than a certain number of workpieces are accumulated at the feed means 10, there can be a stop in the production or of the feeding of further workpieces to the feed means 10. 
     FIG. 5 shows schematically the station 14 having a turret 14A movable around a vertical axis and carrying a double collet 14B which can be horizontally moved. In a pick-up and/or depositing zone associated with the station 14 there is a lift 50 responsive to the controls already described and operative to lift a workpiece from the seat 7 to present it to a collet 14B (and/or to present a workpiece to the seat 7 after receiving the workpiece from one of the collets 14B). 
     In a modified arrangement as shown in FIG. 6, instead of providing the guides 22, the seats (designated 70) are shaped with a saddle 72 to support the workpiece 9 along the upper run TA and with a reversed saddle 74 to support the workpiece along the lower run TR, the workpiece sliding from the saddle 72 to the saddle 74 along a curved portion C1 of the conveyor path by sliding along a portion 76 of the seat. In order to retain the workpieces when moving along the other curved portion C2 of the conveyor path, electromagnetic means 78 can be provided, possibly energized by the passage of the seats of the groups O and I. The workpieces 9 are deposited and picked up along paths shown by the double arrow f10. 
     In the embodiment illustrated in FIGS. 7 to 12, 101 denotes an elongate casing (see FIG. 8) in which are arranged two opposed guides 103, 105 extending in a closed loop to form an annular track having two parallel rectilinear portions which are joined at the ends by curved portions 107. Along the opposite faces of the guides 103 and 105 are located rollers 109 mounted in stationary positions to form tracks for workpiece conveying members 110 which form carriages. The carriages 110 are arranged in an endless loop and may be entrained by an endless chain 112 (or other flexible endless members), the chain being suitably guided along a path located between the guides 103, 105 and the tracks formed by the rollers 109. 
     Means such as those indicated at 114, 116, 118, 120, 122, 124, and intended to effect the same operation or different operations on the workpieces, are provided along a rectilinear portion A of the annular track. The above described arrangement of these means is similar to that of the working stations in the previous embodiment. The means 118, 120, 122 may operate in parallel to effect the same operation in a slower manner than those operated, for instance, by the means 114, 116, 124. The means 118, 120, 122 may each be associated with two mechanical grippers or hands 126 for transferring the workpieces to and from the conveyor portion A by angular movement in a horizontal plane. A similar mechanical gripper is associated with each of the other means 114, 116, 124. 
     A carriage 110 can be engaged by the mechanical grippers and transferred together with the workpiece P transported thereby and which still has to undergo an operation. The workpiece P may for instance, be a stator or an annular rotor of an electric motor, on which a winding is to be applied or another preliminary or complementary or subsequent operation is to be carried out. In the case of an annular workpiece P, the workpiece is located in an annular recess of the carriage 110 (see FIGS. 9 and 10), and the carriage has jaws 130 articulated at 132 to the carriage 110 and biased by springs 134 in such a direction as to engage the workpiece P. The jaws 130 can be opened by means of suitable pushers (not shown) which act in the direction of the arrows f 4  of FIG. 10 and which pass through suitable recesses in the carriage 110 to act on arms 134A of the jaws; the pushers will be arranged to act in correspondence of loading and unloading positions of the manual or automatic type. Unloading may also be provided from the final processing means 124, when the arrangement is such that at least at this station the carriage 110 is carried from the conveyor to the processing means together with the workpiece P for the final working. 
     The several carriages 110 are engaged by the chain 112 by appropriate projections 143 so that a respective carriage is engaged between pairs of adjacent projections in such a manner that each carriage 110 may be seized by a mechanical gripper, such as 126. 
     The chain 112 is driven by a gear wheel 146 located at one of the curved portions of the track and actuated by a pinion 148 meshing with a pinion of a drive unit 150 (see FIG. 11). Appropriately shaped cams 154 are provided on a shaft 152 of the members 146, 148 and are positioned in order to cooperate each with an appropriate feeler 156 of means 158, which may be a switch or the like, to determine the control for the loading, unloading and the intermediate removals, following the same criteria already discussed in connection with the previous embodiment. The positions of the seats defined by the projections 143 of the chain 112 are always controlled by the cams 154, with each seat designated for a specific function.