tarière à coquilles

CONT: La tarière à coquilles [...], dont le diamètre peut varier de 8"" à 10"" [...], comporte deux coquilles en tôle cintrée, l'une attachée rigidement à la tige de la tarière, l'autre fixée à la précédente par des charnières. Après quelques rotations, le cylindre se remplit. Un deuxième modèle [...], à deux tôles fixes, est utilisé en terrains sableux. Pour les trous de grand diamètre, la tarière est manœuvrée à l'aide d'un léger chevalement [...]

CONT: ... the pod auger, consisted of two concave metal plates which were attached to each other by a hinge. When the two plates were closed they formed a pod-shaped cavity which was open at its lower end. The top end of one of the concave metal plates was attached to the end of a rigid rod, while the second plate (attached to the other plate only by its hinge) was left free in order that it could be opened. In operation the rod would be plunged into a hole and forced downward until the pod had filled with soil, then it would be lifted, and such soil and debris as were trapped within the pod was cleared by opening the door of the pod.