ES280055A1 - Improvements in or relating to combination locks - Google Patents

Abstract

A combination lock comprises a rotatable selector knob (not shown) and a push button (not shown) for use in combination to operate the combination mechanism of the lock, the selector knob being mounted on a hollow spindle 33 and the push button being disposed within the knob coaxially with the spindle and co-operating with a rod 7 which is axially slidable within the spindle. The lock described is a modification of that disclosed in Specification 869,533 which has a plurality of concentric locking discs which are selected in turn by the rotatable knob each disc being rotated in turn to a release position by a selected number of depressions of the push button, the push button in the prior disclosure being at one side of the knob instead of concentric with it. In the present construction the spindle 33 selectively moves seven selector claws into engagement with racks there being one rack for each selector claw and locking disc these elements are not shown and are constructed as in the prior Specification. The push button reciprocates a plate 15, Fig. 5, on which the claws are mounted so that the selected rack is moved vertically one step for each depression of the push button to rotate its locking disc. The movement of the plate 15 is accomplished by a bevelled end face 8 of the rod 7 which engages an aperture in a plate 131 secured on the slidable plate 15. Rotation of the spindle 33 is controlled by means of a ratchet wheel 36, Fig. 6, which is engaged by a spring-loaded slidable member 64. The ratchet wheel 36 has six ratchet teeth and a non-ratchet tooth so that the selector knob can be rotated only in one direction from position 1 to position 6, one position for each rack, claw and locking disc, but can be rotated in either direction between positions 6 and 7 this facility allows a bolt 133, Fig. 8, which is controlled by the locking discs to be moved both from the locking to the unlocking position and from the unlocking to the locking position without affecting the locking disc. The movement of the bolt 133 is effected by means of a disc 130 fitted to the spindle 33 and which has a tooth 131. The tooth engages in a recess in an arm 136 which is pivoted to the bolt 133 and hence reverse rotation of the knob from the seventh to the sixth position withdraws the bolt 133. Also mounted on the spindle 33 is a rocking member 139 and this has a slot 144 which is engaged by a pin 145 on the arm 136 it also has a slot 143 which is engaged by a stop peg 62 which is carried by a bar which when the locking discs are in the unlocking positions drops into aligned notches in the discs. The stop peg 62 also extends through an L-shaped slot 142 in the bolt 133 and prevents movement of the bolt when the locking discs are not in the unlocking positions. The arm 136 carries a pin 146 which engages in a groove 147 in the lock casing to control the movement of the arm 136. To allow a door to which the lock is fitted to be open from inside a room without disturbing the locking discs a knob 150, Fig. 2, is carried by the lock casing and this has a pin 154 which engages a slot in a spring-loaded pivoted member 156 attached to the casing a pin 159 is attached to the member 156 and is arranged parallel with the bolt and rotation of the knob 150 causes the pin to engage a slidable member 166, Fig. 7, in the keeper and to move it against the pressure of the spring until it clears the bolt 133. This releases the bolt to enable the door to be opened. To allow the door to be locked by slamming, the bolt is provided with a projection 169 with an inclined surface.