Self-locking snap-hook

A snap-hook having the general shape of a closed ring, the ring defining an opening in a plane, the snap-hook transmitting a tractive load between a first traction element and a second traction element passing through the opening of the ring, the snap-hook comprising:

• a body in the form of a rod curved between a first pivot end and a second free coupling end;
• a closure finger, whose first end is pivoted on the first pivot end of the body, in a pivoting zone, by a transverse pin, and whose second end comes opposite the second free coupling end of the body in a coupling zone;
• wherein the finger may be pivoted about its pivot pin between an open position, in which its second end is spaced away from the second free coupling end of the body towards the inside of the ring, and a closed position in which its second end is in contact with the second free coupling end of the body so as to form a closed ring;
• wherein the second end of the finger and the second free coupling end of the body comprises interlocking shapes fitting one into the other so that, in the closed position, the interlocking shapes prevent the finger from pivoting outwards of the ring and prevent the second respective ends of the finger and of the body from moving relatively axially away from each other;
• wherein the snap-hook comprises load guidance means so that the tractive load transmitted by the first traction element is applied on an intermediate zone of the body whereas the tractive load transmitted by the second traction element is applied to an intermediate zone of the finger, the tractive force between the first traction element and the second traction element thus taking place in a favored traction direction passing through the plane of the ring between the pivoting zone and the coupling zone of the finger and the body, so that application of the tractive load tends to bring the body and the finger back into their respective closed positions;
• wherein the snap-hook has the general shape of a ring elongate in a favored traction direction passing through two opposite ends, said opposite ends forming first and second tractive force application ends;
• wherein the body comprises said first tractive force application end;
• wherein the closure finger comprises said second tractive force application end, so that, during application of a tractive force between a first traction element and a second traction element, the snap-hook tends naturally to be oriented so that its largest dimension is substantially parallel to the direction of the tractive force, the first traction element being hooked on to the body and the second traction element being hooked on to the finger;
• wherein the snap-hook comprises unlockable locking means for selectively immobilizing the finger on the body in the closed position of the snap-hook, and then preventing the finger from pivoting towards its open position;
• wherein the snap-hook comprises a return spring urging the finger in rotation on the body towards its open position, so that, in the absence of a load, unlocking of the locking means causes automatic opening of the snap-hook.

A snap-hook having the general shape of a closed ring, the ring defining an opening in a plane, the snap-hook transmitting a tractive load between a first traction element and a second traction element passing through the opening of the ring, the snap-hook comprising:

• a body in the form of a rod curved between a first pivot end and a second free coupling end;
• a closure finger, whose first end is pivoted on the first pivot end of the body, in a pivoting zone, by a transverse pin, and whose second end comes opposite the second free coupling end of the body in a coupling zone;
• wherein the finger may be pivoted about its pivot pin between an open position, in which its second end is spaced away from the second free coupling end of the body towards the inside of the ring, and a closed position in which its second end is in contact with the second free coupling end of the body so as to form a closed ring;
• wherein the second end of the finger and the second free coupling end of the body comprise interlocking shapes fitting one into the other so that, in the closed position, the interlocking shapes prevent the finger from pivoting outwards of the ring and prevent the second respective ends of the finger and of the body from moving relatively axially away from each other;
• wherein the snap-hook comprises load guidance means so that the tractive load transmitted by the first traction element is applied on an intermediate zone of the body whereas the tractive load transmitted by the second traction element is applied to an intermediate zone of the finger, the tractive force between the first traction element and the second traction element thus taking place in a favored traction direction passing through the plane of the ring between the pivoting zone and the coupling zone of the finger and the body, so that application of the tractive load tends to bring the body and the finger back into their respective closed positions;
• wherein the snap-hook has the general shape of a ring elongate in a favored traction direction passing through two opposite ends, said opposite ends forming first and second tractive force application ends;
• wherein the body comprises said first tractive force application end;
• wherein the closure finger comprises said second tractive force application end, so that, during application of a tractive force between a first traction element and a second traction element, the snap-hook tends naturally to be oriented so that its largest dimension is substantially parallel to the direction of the tractive force, the first traction element being hooked on to the body and the second traction element being hooked on to the finger;
• wherein the snap-hook comprises unlockable locking means for selectively immobilizing the finger on the body in the closed position of the snap-hook, and then preventing the finger from pivoting towards its open position;
• wherein the finger comprises, at its pivot end, an axial housing open in the pivoting zone, the housing having a bottom, the housing being shaped so as to contain a return spring;
• wherein the return spring is a helical compression spring extended by an axial tongue;
• wherein the body comprises, on its pivot end, a first catch and a second catch offset with respect to each other;
• wherein the return spring bears axially in the bottom of the axial housing, whereas the tongue bears axially in one of the catches;
• wherein the first catch is positioned so that the return spring and the tongue tend to return the finger permanently to its open position;
• wherein the second catch is positioned so that the return spring and the tongue tend to return the finger now towards its closed position, now towards it open position, on each side of an intermediate zero return torque position.