Buckle for retarded automatic unlocking of safety belts and harnesses of parachuting equipment and of vehicles

Abstract

Buckle for retarded automatic unlocking of safety belts and harnesses of parachuting equipment or of vehicles, which comprises a frame slideably mounted in a casing and a shaft in the frame for supporting a swinging bolt adapted to imprison the shackle of a strap, or release either instantaneously under the direct action of a manual control means or with a delay under the action of an automatic control means connected to the bolt and actuated by springs compressed by the shackle when the shackle is introduced inside the casing. The automatic control means is itself locked by means adapted to be slowly withdrawn, by means of a brake, under the action of a traction force exerted by the shackle on the bolt providing the sliding movement of the frame against the action of a return spring bringing back the frame to its initial position as soon as the traction force of the shackle on the strap substantially diminishes or ceases.

I claim: 
     
       1. A buckle for retarded automatic unlocking the shackle of safety belts and harnesses, said buckle comprising: a casing for receiving the shackle;   a frame means slideably mounted with respect to said casing and including a frame means return spring connected to said casing for biasing said frame means to an initial position;   a shaft mounted through said frame means;   a bolt rotatably mounted on said shaft for releasably engaging and locking the shackle;   an automatic unlocking control rotatably mounted on said shaft and engaging said bolt for disengaging said bolt from the shackle for unlocking the shackle from said bolt;   an auxiliary locking means including a movable meand supported by said frame means and releasably engaging and locking said automatic unlocking control so as to block rotation of said control to prevent unlocking the shackle from said bolt;   at least one drive spring, connected to said movable means, compressed by the shackle when the shackle is inserted into said casing and biasing said movable means for movement out of engagement with said automatic unlocking control for unlocking said automatic unlocking control   said auxiliary locking means further including a movable latch means withdrawably abutting said movable means for securing said movable means against the biasing of said drive spring and a brake means connected to said movable means for retarding rapid acceleration of said movable means under the urging of said drive spring when said movable latch means is withdrawn from abutting said movable means;   whereby said automatic unlocking control is slowly unlocked under the action of a traction force exerted by the shackle on said bolt, which traction force is sufficient to slideably move said frame means against the bias of said frame means return spring, said frame means return spring returning said frame means to its initial position as soon as the traction force of the shackle on said bolt substantially diminishes.   
     
     
       2. A buckle according to claim 1 wherein said automatic unlocking control comprises: a lever arm having one end rotatably mounted on said shaft; and   a lever arm return spring connected to said lever arm for biasing said lever arm into engagement with said bolt for disengaging said bolt from the shackle;   and wherein said movable means of said auxiliary locking means includes:   a further shaft rotatably supported by said frame means;   a locking arm integrally connected to said further shaft for engaging the other end of said lever arm for locking said lever arm against the bias of said lever arm return spring;   a pendulum means integrally connected to said further shaft and having a plurality of extremities, a first extremity of said plurality of extremities being connected to said brake means and a second extremity of said plurality of extremities being connected to said drive spring, whereby said drive spring biases said pendulum for rotation of said further shaft for disengagement of said locking cam from the other end of said lever arm and said brake means retards the rapid acceleration of the rotation;   a stop member integrally connected to said further shaft for preventing the rotation of said further shaft when said movable latch means is abutting said stop member;   and in addition wherein said movable latch means includes a pin withdrawably abutting said stop member for securing said stop member, and preventing rotation of said further shaft; said pin being withdrawn from securing said stop member, thereby permitting rotation of said further shaft and unlocking of said lever arm, when the traction force exerted by the shackle on said bolt is sufficient to slideably move said frame means against the bias of said frame return spring.   
     
     
       3. A buckle according to claim 2 wherein said movable latch means further includes a platen transversely displaceably mounted in said frame means, said pin being mounted on said platen adjacent said stop member; and wherein said casing includes a further stop member retractably fixed thereto adjacent said platen;   said platen including an oblique slope which cooperates with said further stop member when said frame means slides in said casing to transversely displace said platen in said frame means thereby withdrawing said pin from abutting said stop member;   said further stop member being retracted for eliminating the automatic unlocking of the shackle from the bolt.   
     
     
       4. A buckle according to claim 3 further including a platen return spring for biasing said platen to an initial position. 
     
     
       5. A buckle according to claim 2 wherein said movable means of said auxiliary locking means further includes an anti-return cam integrally connected to said further shaft; and wherein said buckle further comprises:   a lamella spring having one end fixed to said frame means and the other end retractably abutting against said anti-return cam for preventing rotation of said further shaft and return of said cam into its lever arm engagement position when said lever arm is unlocked from said cam; and a manual resetting plunger which acts on said lever arm to rotate said lever arm against the bias of said lever arm return spring;   said lever arm including a pawl which abuts against said lamella spring, when said lever arm is acted on by said manual resetting plunger, to retract said lamella spring from abutting against said anti-return cam to allow said locking cam to return to its lever arm engagement position and lock said lever arm.   
     
     
       6. A buckle according to claim 5 wherein said frame means has an additional stop member and said pendulum means has a third extremity; said buckle further comprising a resetting spring connecting said third extremity to said additional stop member, said resetting spring being compressed by said pendulum, means when said further shaft rotates during the unlocking of said automatic unlocking control, said compressed resetting spring causing the return of said locking cam to its lever arm engagement position to re-engage and relock said lever arm when said pawl of said lever arm retracts said lamella spring from abutting against said anti-return cam.   
     
     
       7. A buckle as claimed in claim 2 further comprising: a cover for said buckle;   a viewing aperture formed in said cover; and   a resetting indicator element integrally connected to one of said plurality of extremities of said pendulum means and located opposite said viewing aperture and provided with an indicator which when in correspondence with said viewing aperture indicates that said auxiliary locking means has locked said automatic unlocking control.   
     
     
       8. A buckle according to claim 2 wherein said stop member is displaceable on said further shaft for adjusting the sensitivity of said auxiliary locking means. 
     
     
       9. A buckle according to claim 1 wherein said movable means of said auxiliary locking means includes a pendulum having a first extremity; and wherein the brake means is a mercury micropump comprising:   a cylinder including a return channel;   a nozzle formed in said return channel;   a needle screw positioned in said nozzle for adjusting the opening thereof; and   a piston slideable in said cylinder and connected to said first extremity of said pendulum for slowly forcing fluid in said cylinder through said nozzle and said return channel back into said cylinder behind said piston.   
     
     
       10. A buckle according to claim 1 wherein said bolt includes a release heel; said buckle further comprising a manual control means for instantaneously releasing the shackle from said bolt, said manual control means comprising:   a slide movably mounted in said casing and having one end extending out of said casing to afford manual operation and the other end abutting against said release heel of said bolt for rotating said bolt around said shaft so as to disengage said bolt from the shackle for unlocking the shackle from said bolt, said drive spring instantaneously ejecting the unlocked shackle from said casing; and   a slide return spring biased against said slide to return said slide to an initial position.   
     
     
       11. A buckle according to claim 1 wherein said frame means additionally includes a stirrup located outside said casing and mounted on said shaft, and wherein said frame means return spring is compressed between said casing and the cross-piece of said stirrup when the traction force is exerted by the shackle on said bolt. 
     
     
       12. A buckle according to claim 11 wherein said casing includes two lateral walls, each having an oblong aperture therein and wherein said shaft passes through said apertures and is displaceable in said aperture in the longitudinal direction of said buckle. 
     
     
       13. A buckle according to claim 1 wherein said automatic unlocking control includes a bolt recall spring which biases said bolt in a shackle locking position. 
     
     
       14. A buckle according to claim 1 wherein said casing includes a groove, and wherein said bolt includes an auxiliary locking heel which engages said groove under the action of the traction force exerted by the shackle on said bolt. 
     
     
       15. A buckle according to claim 1 wherein shackle includes a pivot for engaging a triangle plate when said buckle is to be used to lock the shackle of a parachute harness, said pivot permitting said triangle plate and said shackle to be disengaged so that a strap of said parachute harness connected to said triangle can be separated from a strap of said parachute harness connected to said shackle. 
     
     
       16. A buckle according to said claim 1 wherein the sensitivity of the automatic unlocking control is determined by the biasing force of the frame means return spring.