A crop cutting device for an agricultural harvester comprising: a crop guiding surface , a plurality of substantially parallel knives mounted below the crop guiding surface and aligned with respective slots in the crop guiding surface , the knives being movable between a retracted inoperative position below the crop guiding surface and an extended operative position wherein at least a portion of a cutting edge of the knives projects above the crop guiding surface , and an actuating mechanism for moving the knives between the retracted inoperative position and the extended operative position, the actuating mechanism comprising a plurality of movable operating members , associated with respective ones of the plurality of knives and movable from a first position in which the knives are in the retracted inoperative position, to a second position in which the knives are in the extended operative position, a support frame configured to hold the operating members in a sliding relation to the support frame , and an actuator coupled to the support frame for moving the support frame between an employed position and a retracted position, the employed position being closer to the knives than the retracted position, characterized by a knife insert assistant that is coupled to the support frame and configured for blocking a sliding movement of the operating members relative to the support frame during a movement of the support frame from the retracted position to the employed position. a crop guiding surface , a plurality of substantially parallel knives mounted below the crop guiding surface and aligned with respective slots in the crop guiding surface , the knives being movable between a retracted inoperative position below the crop guiding surface and an extended operative position wherein at least a portion of a cutting edge of the knives projects above the crop guiding surface , and an actuating mechanism for moving the knives between the retracted inoperative position and the extended operative position, the actuating mechanism comprising a plurality of movable operating members , associated with respective ones of the plurality of knives and movable from a first position in which the knives are in the retracted inoperative position, to a second position in which the knives are in the extended operative position, a support frame configured to hold the operating members in a sliding relation to the support frame , and an actuator coupled to the support frame for moving the support frame between an employed position and a retracted position, the employed position being closer to the knives than the retracted position, a plurality of movable operating members , associated with respective ones of the plurality of knives and movable from a first position in which the knives are in the retracted inoperative position, to a second position in which the knives are in the extended operative position, a support frame configured to hold the operating members in a sliding relation to the support frame , and an actuator coupled to the support frame for moving the support frame between an employed position and a retracted position, the employed position being closer to the knives than the retracted position, <EOS>