These openings 78 and 80 receive screws, bolts or other means for securing the brackets, glide plates or contacts 70 and 72 into place onto deck 60 in holes 79 and 81.Looking more specifically at FIG. 4 in conjunction with the showing of FIG. 2 it can be seen that a roller bracket 84 has been shown constituting a pair of bracket arms 86 and 88.