A staple apparatus can comprise a staple head movable in a first staple direction from a head retracted position to a head extended position. The staple apparatus can further comprise an indexing apparatus comprising an index biasing member and an indexing member. The indexing member can be positioned at least partially within an indexing area and biased with the index biasing member toward a member extended position relative to the indexing area. The indexing member can define a rung travel path and can further comprise an indexing tab comprising a ramp surface positioned to taper the rung travel path in the first indexing direction. The indexing tab can further comprise a shoulder positioned past at least a portion of the ramp surface in the first indexing direction. In further embodiments, a staple chain positioning apparatus can comprise a push member movable in an extension direction.

A device for dispensing an individual plastic fastener from a supply of fastener stock includes a motor-driven head assembly adapted to receive the supply of fastener stock, sever an individual fastener from the supply and in turn eject the severed fastener. The head assembly includes a pair of needle block assemblies that retain corresponding hollow needles, each needle block assembly being shaped to define a feed channel that transitions a side rail for the fastener stock into axial alignment behind its corresponding needle. In addition, at least one needle block assembly includes a rearward shelf and a forward bowing plate. In use, the lowermost cross-links of the fastener stock fittingly align between the shelf and the bowing plate. In this manner, the lowermost cross-links are limited to distort uniformly upward within the single plane defined by the pair of feed channels, thereby optimizing feed reliability of the device.