Hold-down assembly

摘要

A hold-down assembly for retaining a portable electronic unit within an avionics equipment mounting tray includes a shaft, a locking collar, and an actuator knob. The shaft is coupled to pivot with the mounting tray. The locking collar slides along the shaft to engage the portable electronic unit. The actuator knob includes a knob body, a ratchet plate having detent holes within the knob body, a ball bearing, and a compression spring within the knob body. As the actuator knob is rotated to move along the shaft, the knob body and the ball bearing rotate with respect to the ratchet plate, and the ball bearing is forced against a spring bias of the compression spring as the ball bearing travels between adjacent detent holes.

主权项

1. A method of retaining a portable electronic unit within an avionics equipment mounting tray that has a hold-down assembly including a shaft coupled to the avionics equipment mounting tray and a locking collar slidably disposed on the shaft to hold the electronic unit in the tray, the method further comprising:
sliding the locking collar along the shaft to interact with a part of the portable electronic unit; rotating a threaded rotatable actuator knob that is threadably engaged on threads of the shaft to advance the actuator knob along the shaft and into engagement with the locking collar to secure the collar and apply a locking force on the portable electronic unit; simultaneously with rotating the actuator knob, sliding a non-rotatable ratchet plate along the shaft together with the rotatable actuator knob and rotating and ratcheting the rotatable actuator knob with respect to the non-rotatable ratchet plate to secure the rotation of the actuator knob relative to the non-rotatable ratchet plate and hinder undesired rotation of the actuator knob and for holding the electronic unit in place.