Patent GB-1155087-A (GB)
Title: Improvements in or relating to Releasable Fastening Devices
Inventor: PICKARD PAUL ROBERT
IPC: E05B65/32
Filed: 1965-11-26
Abstract: 1,155,087. Latch fastenings. WILMOT-BREEDEN Ltd. 21 Nov., 1966 [26 Nov., 1965], No. 50274/65. Heading E2A. A vehicle door fastening of the type which in use releases the door from outside by means of an external push button 10 and which includes locking means cooperative to turn a .stem 14 of the push button to a locking position in which the push button is inoperative to release the door has a positive stop 20 which blocks normally operative i.e. releasing movement of the push button when the stem is in the locking position, the stop being yieldable in the event of the application of excessive force to the push button in an attempt to over-ride the locking and the arrangement being such that in the locking position the stem does not operate to release the device even if the stop yields to allow push button movement. In the construction shown the arrangement is such that when the stop has yielded the device remains fully operative with the push button providing a free-wheeling action in the locking condition of the device. The device shown uses a rotary latch member 4 which is mounted on a shaft 8 which projects through a back plate 2, the opposite end of the shaft 8 carrying a ratchet wheel 7 which is engaged by a pawl lever 6. The stem 14 of the push button 10 has a step 18 which is engageable with a projecting stud 15 of a contactor lever 5 when the push button is depressed to move the contactor lever; the contactor lever is engageable with the pawl 6 and on the depression of the push button releases it from the ratchet wheel 7 so that the latch member 4 is freely rotatable. The stem 14 of the push button is of plate-like form and is fitted into the body of a springtumbler lock 16 which is mounted in the body of the push button 10; the lock body can be turned by the appropriate key to rotate the stem 14 between a normal operative position and a locking position; in the locking position the stem 14 is out of alignment with the contactor stud 15 and a step 19 of the stem is aligned with the positive stop 20 which as shown is a tab bent up from the back plate 2, thus the stop 20 blocks movement of the push button should an attempt be made to depress the latter but if for example a hammer blow is applied to the push button 10 the stop 20 will yield before any other part of the device is damaged but since the stem 14 is not in alignment with the contactor stud 15; the hammer blow is ineffective to release the latch member, the stud merely free-wheel ing. The push button stem has a tongue section 17 which engages a slot 22 in one side limb 23 of a stirrup shape locking lever 24, pivotally mounted through the other side limb 25 on a flange 26 on the back plate 2; this lever 24 forms part of an internal locking means which includes a door sill control member 27 which is attached to the cranked projecting end of the limb 25. Operation of the internal locking means from inside the door acts through the locking lever 24 to turn the pushbutton stem 14 to the locking position. The latch member 4 is engageable with a toothed lower limb 28 of a U shaped keeper block 29; the keeper block 29 is fixed to a vehicle body panel 30 adjacent the shut face of a door and a guide block 31 mounted on the shut face enters between the limbs of the Keeper; the upper limb houses a spring loaded wedge 32 which provides vertical restraint for the door when closed. The contactor lever 5 is also displaceable by a remote control lever (not shown) to allow release of the latch member from inside the door. The stem 14 is either made of sheet metal or can be a die casting.