the backing plate 40 locks against the spike plate 50 firmly fixing the spikes 70 in place when in the course of debris collection it becomes necessary to replace a damaged spike the human operator need only temporarily remove the attachment screws 23 separate the backing plate 40 from the spike plate 50 and exchange the damaged spike with a new spike the human operator would then reattach the backing plate 40 and spike plate 50 and reset the attachment screws 23 both the backing plate 40 and the spike plate 50 each have three more aligning holes one of these holes 42 and 52 respectively is disposed in the center of the respective plates this central hole allows the pusher rod 30 of the trigger system to pass from the shaft 20 through backer plate 40 and the spike plate 50 unobstructed to the ejection plate 60 the other pair of holes 41 and 51 respectively referenced above which pass through the backing plate and the spike plate facilitate the shoulder bolts 80 which are attached to the ejection plate 60 with respect to the backing plate 40 these holes 41 may be cylindrical holes or they may be slots cut into the backing plate 40 as shown in the drawings such holes 41 will be larger than the head of the shoulder bolts 80 with respect to the spike plate 50 they are a pair of holes 51 sized just larger than the shaft of the shoulder bolts.