Abstract: In a seatback pivotable joint, a pin, having an annular groove formed around the axis thereof, is secured to a stationary member of a vehicle body. A bracket having an opening therein is secured to the seatback. The pin passes through the opening of the bracket so that the annular groove of the pin is located behind the opening with respect to the stationary member. A catcher is provided for engaging the annular groove of the pin and for retaining the catcher in a predetermined position. A device for moving the catcher is supported by the bracket and moves the catcher from its inoperative position to the predetermined operative position thereby retaining the bracket relative to the pin.