plug moves to the right end 85 of the link which receives rounded bearing surface 88 of the shaft moves the shaft to the right which places end 28 into the open end 72 of the housing limiting movement of the shaft this assures clearance between housing 68 and member 34 a hollow cylindrical link 84 is present within housing 68 between the shaft 80 and spring means 82 this link 84 is seen to be closed at the end 86 thereof which is toward the spring means 82 and is open at its other end 85 at such open end 85 the link 84 receives the rearward portion of second shaft 80 in the showing of fig5 the shaft 80 is seen to be positioned in its first or retracted position within the link 84 it is noted that in this position the rearward end of shaft 80 which is formed into a rounded bearing like surface 88 is received at the recessed bottom 90 of link 84 further to be noted is that a cross piece 92 passes transversely through shaft 80 and defines projecting pins 94 and 96 i e which project laterally at the opposed sides of shaft 80 to be noted is that the interior of cylindrical link 84 has its wall 87 undercut at points rearward of 96 so that it will be clear that in the configuration shown in fig5 the shaft 80 is free to rotate while for clarity and full understanding the friction number 40.