Gravity-operated feeder systems that require no drive mechanisms can be built inexpensively. This section outlines the principles and features of these feeder systems.

[Table 1] Features of gravity-operated feeder systems (chute type systems)

1. Descriptions

(1) Drop type

The distance (L) from storage hopper to workpiece holding carrier and the time (t) required for workpiece feeding can be determined using the following formula (See Fig. 1a):

The orientation of the workpiece can be kept unchanged while dropping using the characteristics of the shape of each workpiece and the position of the center of gravity.

(2) Sliding type

The feeding speed can be controlled using two design parameters: angle (θ) and friction coefficient (μ) of the slide chute (See Fig. 1b):

The friction coefficient (μ) is adjustable to some degree using the contact area of the transferred workpiece with the sliding surface. Therefore, the sliding speed can be controlled via the chute sliding surface, which may consist of, e.g., punched plates. The time t required for feeding can be determined using the following formula:

If equipped with a vibrational parts feeder, a sliding type feeder system is capable of aligned feeding of workpieces with complicated shapes. This section assumes the use of simplistic jigs, such as auxiliary jigs, for use in one-piece flow production lines.