The present invention relates to apparatus for loading/unloading workpieces from a work station and, in particular, to apparatus for loading and unloading disc-like workpieces from a carrier and having associated endless drive mechanisms for controlling horizontal and vertical workpiece movement.
Loading and unloading disc-like workpieces from a work station has heretofore generally been accomplished via apparatus which supports the discs at one or more times on their flat surfaces as the discs are conveyed to or from the work station. Intermediate apparatus, in turn, manipulates the discs so as to rotate the discs to a desired orientation relative to the work station.
Depending upon the ultimate use for the discs and the type of materials used in the manufacture of the discs, such manipulations may damage the discs so as to make them unusable. In particular, during the manufacture of magnetic discs for computer memory applications and which eventually may contain data on one or more surfaces thereof, it is particularly important to minimize any contact with the ultimate data containing surfaces. It is therefore desirable to grasp the discs in a fashion where the upper and lower surfaces do not contact other than the intended work stations during the work process.
The present apparatus contemplates such a mechanism in that it grasps an interior edge and vertically loads/unloads the discs from a rack containing a plurality of the discs and horizontally conveys the discs to a work station where an appropriate operation is performed, such as buffing. It is to be recognized that while the present apparatus will be described hereinafter with respect to the loading and unloading of discs and relative to a buffing station, it may be suitably adapted for loading/unloading other workpieces and conveying the same to and from other work stations via associated transfer mechanisms.
Generally, the present apparatus is horizontally actuable via a notched endless belt and an associated driven gear and idler gear. The belt coacts with mating gears coupled to a vertically actuable tower assembly containing a workpiece holder. The horizontal position of the workpiece holder is controlled by means of a magnetic transducer which detects and counts various index markings. The vertical position, on the other hand, is controlled by means of a pair of driven sprockets, a pair of associated idler sprockets and a pair of endless chains coupled therebetween. A workpiece holding assembly is, in turn, coupled to the chains via an axle that is permanently affixed to each of the chains and which passes through a laterally floating bearing, whereby the workpiece holder moves up and down as the endless chains rotate about the sprockets.
In an alternative embodiment, a driven lead screw, along with a coacting position encoder and controller, is used to control horizontal work holder movement. In yet another embodiment, a pivoting roller arm coacts with the workpiece holder, between a pair of limit switches to control vertical work holder movement. A vibration dampened drive coupling isolates the roller arm from the drive motor.
The apparatus finds particular advantage in that it independently operates in the horizontal and vertical directions as it removes and replaces unfinished/finished discs from the disc holder. Rotary motion may also be independently applied by means of a rotary spindle coupled to the workpiece holder.
The above objects, advantages and distinctions of the present apparatus as well as various others will, however, become more apparent upon reference to the following description thereof with respect to the appended drawings.