Abstract: A knuckle arm is connected to a machine body and a top cover of a machine, and includes a mounting seat, a connecting seat, a sliding seat, and a resilient member. The mounting seat includes a mounting block disposed fixedly on the machine body, and a pivot block extending integrally from the mounting block and having a cam edge. The connecting seat is connected pivotally to the pivot block of the mounting seat, and is attached to the top cover. The sliding seat is disposed slidably within the connecting seat, and has an integral projection. The resilient member is disposed between the mounting seat and the sliding seat, and biases the sliding seat to move toward the mounting seat so as to keep the projection of the sliding seat in contact with the cam edge of the mounting seat.

Abstract: A knuckle arm is connected to a machine body and a top cover of a machine, and includes a mounting seat, a connecting seat, a sliding seat, and a resilient member. The mounting seat includes a mounting block disposed fixedly on the machine body, and a pivot block extending integrally from the mounting block and having a cam edge. The connecting seat is connected pivotally to the pivot block of the mounting seat, and is attached to the top cover. The sliding seat is disposed slidably within the connecting seat, and has an integral projection. The resilient member is disposed between the mounting seat and the sliding seat, and biases the sliding seat to move toward the mounting seat so as to keep the projection of the sliding seat in contact with the cam edge of the mounting seat.