Device for locking and unlocking by means of a wrench, a plug or lid on a frame, notably of a manhole

Abstract

A device for locking and unlocking a wrench, a plug or lid on a frame, notably of a manhole. A bolt is mounted and guided in translation in a casing of the plug and is held in a locking position by a pre-stressed coil compression spring, between the bolt and a bottom wall of the casing, the bolt ( 8 ) comprising a transverse branch on which an end of the wrench may act in order to displace the bolt towards a position for unlocking the plug from the frame.

1 . A device for locking and unlocking, with a wrench, a plug on a frame, the device comprising: 
 a lock integral with the plug, wherein 
 the plug has an aperture providing access to the lock for the wrench, and  
 the wrench includes an arm with an end for maneuvering the lock, when the wrench is introduced into the aperture, from a locked position, in which a bolt of the lock is retained captive by a keeper of the frame, to an unlocked position in which the bolt is released from the keeper, the lock further including  
   a casing in which the bolt is removably mounted and guided in translation; and    a coil compression spring interposed between the bolt and a bottom wall of the casing, holding the bolt in the locked position, wherein the bolt has an end adjacent to the spring and including a branch transverse to a longitudinal direction of the bolt, extending through two guiding grooves in respective side walls of the casing, parallel to the longitudinal direction of the bolt, at least one of the guiding grooves passing through a first side wall of the casing and into which the end of the arm of the wrench may be introduced, and which may act on a corresponding end of the transverse branch of the bolt to displace the bolt translationally to a position of release from the keeper, against a return force of the spring.    
   
   
       2 . The device according to  claim 1 , wherein the first side of the casing including the guiding groove further comprises a slot perpendicular to the first wall, opening into the guiding groove so the end of the arm of the wrench can be introduced into the guiding groove.  
   
   
       3 . The device according to  claim 1 , wherein 
 the wrench comprises a handle parallel to the arm with the end, and a bar connecting the handle to the arm,    the handle, the bar, and the arm with the end are located in a common plane and    the aperture of the plug providing access to the lock is a slot extending in a plane perpendicular to the longitudinal direction of the bolt so that the arm and the end can be introduced by displacing, in its own plane, the wrench, perpendicular to the plane of the plug, and the end of the arm of the wrench may be introduced into the guiding groove of the wall of the lock casing by translating the arm parallel to the slot of the plug towards the casing and may act on the transverse branch of the bolt to displace the bolt to the position of release from the keeper by rotating the handle of the wrench in a corresponding direction around the bar.    
   
   
       4 . The device according to  claim 3 , wherein the plug comprises at least one wall extending perpendicular from and under the plug, parallel to and as an extension of the slot so that the end of the arm of the wrench can be guided towards the guide groove of the wall of the lock casing.  
   
   
       5 . The device according to  claim 4 , wherein the plug comprises two guiding walls for guiding the arm of the wrench a first of the guiding walls including, facing the lock casing, a plate diverging from a second of the guiding walls and providing limited rotation of the arm of the wrench in the direction for releasing the bolt from the keeper when the end of the arm has been introduced into the guiding groove of the wall of the casing.  
   
   
       6 . The device according to  claim 1 , wherein the end of the arm of the wrench is bent and extends parallel to the arm towards the handle and in a direction opposite the bar connecting the arm to the handle.  
   
   
       7 . The device according to  claim 6 , including a shim integral with the plug and at least one guiding wall for guiding the wrench on side of the lock casing and fitting into a substantially U-shaped portion defined by the arm of the wrench between the bar and the end of the arm, when the end of the arm is introduced into the guiding groove of the wall of the casing.  
   
   
       8 . The device according to  claim 1 , wherein the bolt comprises two flexible tabs located in a common plane with the transverse branch of the bolt, opposite the transverse branch and diverging from each other in a direction opposite the transverse branch for holding the bolt in the lock casing after latching, when mounting the bolt in the casing, the tabs being respectively located in respective windows in the side walls of the casing opposite the bottom wall and both guiding grooves of the transverse branch of the bolt, the free ends of the flexible tabs being supported, in the locking position of the plug by the return force of the spring, on edges of the windows, opposite the guiding grooves.  
   
   
       9 . The device according to  claim 1 , wherein the branch of the bolt is part of a T-shaped end of the bolt.  
   
   
       10 . The device according to  claim 1 , wherein the bolt is a plastic material, and the return spring is the same material as the bolt.  
   
   
       11 . The device according to  claim 10 , wherein the bolt and the return spring are inserted in the casing through a conjugate imprint of a front wall of the casing against the return force of the spring and are elastically in respective windows.  
   
   
       12 . The device according to  claim 10 , wherein the bolt and the return spring are inserted in the casing through an end aperture of the casing opposite a bottom wall of the casing.  
   
   
       13 . The device according to  claim 1 , wherein the lock casing and walls for guiding the arm of the wrench are integral with the plug.