Platform truck apparatus, workpiece transfer method, and workpiece conveyor equipment

A method of transporting a workpiece by a cart configured to move along a closed transportation path,

• wherein the cart is moved by a drive source positioned outside the cart;
• the transportation path includes:
• a first low speed movement path;
• a first high speed movement path extending from the first low speed movement path and being configured to move the cart at high speed in comparison with the first low speed movement path;
• a second low speed movement path extending from the first high speed movement path and being configured to move the cart at low speed in comparison with the first high speed movement path;
• and
• a second high speed movement path extending from the second low speed movement path to the first low speed movement path and being configured to move the cart at high speed in comparison with the second low speed movement path,
• a first workpiece transfer apparatus extends to the first high speed movement path and is configured to transfer the workpiece from outside of the transportation path to the cart;
• and
• a second workpiece transfer apparatus extends to the second high speed movement path and is configured to transfer the workpiece on the cart to the outside of the transportation path,
• the method comprising the steps of:
• in the first low speed movement path, arranging a plurality of the carts in series to contact one another, and placing parts to be attached to the workpiece, on the cart;
• in the first high speed movement path, allowing one of the carts to travel at high speed, and stop at one intermediate position, for loading the workpiece on the cart by the first workpiece transfer apparatus;
• in the second low speed movement path, arranging a plurality of the carts in series to contact one another, and attaching the parts to the workpiece;
• and
• in the second high speed movement path, allowing one of the carts to travel at high speed, and stop at one intermediate position, for moving the workpiece on the cart to the outside of the transportation path, by the second workpiece transfer apparatus.

A workpiece transportation apparatus for transporting a workpiece by a cart, comprising;

• a drive source provided outside the cart and configured to move the cart;
• a transportation path including:
• a first low speed movement path configured to allow the cart to move at low speed to perform operation of placing parts to be attached to the workpiece, on the cart;
• a first high speed movement path extending from the first low speed movement path and being configured to allow the cart to move at high speed in comparison with the first low speed movement path;
• a second low speed movement path extending from the first high speed movement path and keeping movement of the cart at low speed in comparison with the first high speed movement path to perform operation of attaching the parts to the workpiece;
• and
• a second high speed movement path extending from the second low speed movement path to the first low speed movement path and being configured to allow the cart to move at high speed in comparison with the second low speed movement path;
• and
• a control unit configured to control the drive source to:
• in the first low speed movement path and the second low speed movement path, arrange a plurality of the carts in series to contact one another;
• in the first high speed movement path, allow one of the carts to travel at high speed, and stop at one intermediate position;
• and
• in the second high speed movement path, allow one of the carts to travel at high speed, and stop at one intermediate position.