5183. Newton, H. E., [Carleton, H. G.]. March 19. Electrically-controlled fastenings; locks, key.- Relates (a) to controllers for rendering boltactuating mechanism operative or inoperative, (b) to circuit - closing devices which complete the electric circuit only when the bolt mechanism is actuated, (c) to key-operated circuit-closing devices, and (d) to protective plates for use with locks. Fig. 1 shows one arrangement of the lock. The bolt 5 is operated from inside the door by the handle 43 operating a sliding bar, and from outside by the handle 17 operating the bar 10. The bar 10, however, cannot be drawn back sufficiently far to release the bolt, unless the magnet 27 is energized so as to hold the pivoted catch 22 up. If no current is flowing round the magnet, the catch 22 falls, as soon as the bar 10 is drawn back, and engages the slot 26. To prevent the bar 22 from coming in contact with the poles of the magnet, an arm 30 is provided ; at the end of the arm a roller 31 may be mounted, to diminish friction. To prevent waste of battery power, the circuit through the magnet is not completed immediately the external circuit-closer is operated, the circuit being broken within the lock and completed only when the handle 17 is turned. For this purpose one of the wires is oonnected with the sector 34 on the handle spindle, while the wire leading to the magnet is attached to the spring 32. It will be seen that contact is established between the sector 34 and spring 32 before the toothed sector 18 commences to draw back the bar 10. In a second form of lock, the handle draws back a sliding bar to which a hook controlled by a magnet is pivoted. When a current is passed through the magnet, the hook is raised and connection established between the sliding bar and the bolt. In a third form, the slide operated by the handle is always in engage ment with the bolt, but is blocked until a pivoted catch is lifted by the magnet. Fig. 10 shows a fourth form of lock. To draw back the bolt 5, the handle is first turned so as to move the slide 90 inwards, the effect of which is to raise the pivoted catch 97 to the position shown in dotted lines. If the circuit through the magnet is complete, the catch 97 is held up, and the bolt can be drawn back by a reverse movement of the knob. If, however, no current is passing round the magnet, the catch 97 falls and blocks the bolt when the knob is turned back. With this construction it might be possible to turn the knob so as to lift the catch 97 and then force back the bolt by means of a tool inserted between the door and the jamb, the end 96 of the bolt being maintained in contact with the end of the bar 90. A notch in the top of the bolt, in which the catch 97 engages, may be arranged to prevent this, or a lever 103 may be employed, as shown. The pin 107 raises the front end of the lever into the path of the bolt, as the bar 90 is moved forward to raise the catch 97, so that the bolt cannot move until the bar 90 has been drawn back through some distance. Fig. 15 shows a key-operated circuit-closing device for use with the locks described, or with other electric locks, such as those described in Specification No. 16,734. A.D. 1898. The construction resembles that of the Yale lock, with the exception that the outer barrel 203 is not rigidly fixed. When the proper key is inserted and turned, the inner barrel 204 alone is moved, closing the lock circuit. If, however, an attempt is made with a key which does not set the pin tumblers in their proper positions, the outer barrel 203 turns with the inner one. The motion of the outer barrel breaks the circuit, which would be otherwise completed, and at the same time closes another circuit through a bell, giving an alarm. To prevent the circuit-controlling apparatus from being removed, a protective plate 230 is employed. The screws 232 are inserted in recesses in the plate, to prevent their heads from being cut off. The screws are insulated from the plate, and, if an attempt is made to withdraw them, their threaded portions, which are enlarged, come into contact with the plate, and complete an alarm circuit. The plate is insulated from the lock barrel 204 by a flanged collar 260, the flange on which is embraced between the flange 207 on the barrel and the shoulder 272 of the plate. An attempt to drill through the flange 207 will result, therefore, in the completion of the alarm circuit.