for the clevis assembly 106 which operates as a first class lever a stub shaft 112 extends obliquely from the clevis assembly 106 an operator bar 114 illustrated in fig2 includes a complementarily sized axially extending blind opening 116 the operator bar 114 may be engaged upon the stub shaft 112 to pivot the clevis assembly 106 about the fulcrum defined by a pivot pin 104 the clevis assembly 106 also defines a second pair of spaced apart aligned apertures 118 which receive a second pivot pin 120 the second pivot pin 120 passes through a complementarily sized radially disposed aperture 122 in an actuator rod 124 the actuator rod 124 includes a step and a reduced diameter region 126 having threads 128 adjacent its terminus the actuator rod 124 extends through the aperture 64 in the second transverse panel 62 and receives a compression spring 130 thereabout the compression spring 130 is axially constrained between a face of the transverse panel 62 and a wedge block 132 the wedge block 132 is generally u shaped and includes a pair of spaced apart arms 134 which each define a spaced apart obliquely oriented cam surface 136 disposed between the arms 134 is an obliquely disposed latch surface 138 the wedge block 132 is constrained to translate obliquely in the passageway 72 defined by the interior panels 68 and 70 the wedge block 132 also defines a through aperture 140 which receives the reduced diameter region 126 of the actuator rod.