792,386. Door latches. GENERAL MOTORS CORPORATION. Jan. 5, 1956 [Jan. 19, 1955; Jan. 19, 1955; Feb. 17, 1955], No. 426/56. Class 44 A door latching system for an automobile-body having on each side a pair of doors 2, 3, Fig. 1, hinged at their far edges and unseparated by a body pillar, comprisesan electrically operable latch 11 for latching together the adjacent edges of the doors and a latch 16, 17 for latching. each door to the body. As shown in Fig. 2 the latch 11 is mounted on the front door 2 and engages a striker 13 on the rear door 3. The latch 11 comprises a frame 30 upon which a bolt 12 is slidably mounted in a hollow casing 12a. Solenoids 14 and 15 are carried on the frame 30 and an arm 26 of solenoid 15 unlatches the bolt when the arm rotates through an arc in a clockwise direction as shown and an arm 25 of the solenoid 14 moves the bolt to its latching position when the arm rotates in a counterclockwise direction. The solenoids 14 and 15 are controlled by six single pole, single throw switches in the front door and four single pole, single throw switches in the rear door. The switches are arranged in pairs, each pair having a common actuator. In the front door adjacent the latch 11 there is a pair of switches a, k, Fig. 1. The switch a is closed when the door is closed and the switch k is open. A push button 5 is mounted on the outside of the door and a handle 6 is mounted on the inside of the door and both of these are connected to an actuator 21. When the actuator is rotated by depression of the push button or rotation of the inside handle 6 it opens the switch a and closes the switch k. The closing of the switch k connects the vehicle battery to the solenoid 15 and the bolt is moved to its unlatching position. Opening the door causes a sill switch d in the door to open and a sill switch g also in the door to close. The sill switch d prevents the solenoid 14 being energized while the door is open and 'the sill switch g completes a holding circuit for the solenoid 15 so that it remains energized until the bolt is fully unlatched when the bolt opens a limit switch f to break the circuit and closes a limit switch e to prepare the latching circuit. Release of the push button or inside handle returns the switches a and k to their original condition and when the front door 2 is slammed shut, assuming the rear door 3 to be shut, sill switches d and g are also returned to their original condition and since the limit switch e has been closed by the retraction of the bolt a circuit is provided to energize the solenoid 14 which moves the bolt back to its latching position. When the bolt reaches its latching position an actuator 23 opens the limit switch e and closes the limit switch f. To open the rear door 3 a push button 8 is provided on the outside of the door and a rotatable handle 9 is provided on the inside of the door. When the push button is depressed or the handle turned they rotate an actuator 24, Fig. 3, which opens a switch b and closes a switch j. The closing of the switch j energizes the solenoid 15 to unlatch the bolt and when the rear door is pulled open it opens a sill switch c to prevent the solenoid 14 being energized while the door is open and closes a sill switch h which maintains the solenoid 15 energized even though the push button or inner handle are released to return switches b and j to their original condition. The circuit through the solenoid 15 is maintained until the limit switches e and f are changed over as previously described. When the rear door is slammed shut with the front door closed, sill switch h is opened and sill switch c is closed, the switch c completing a circuit through the solenoid 14 to move the bolt 12 to its latching position. The provision of the sill switches ensure that the bolt cannot be moved to latching position -so long as either door is open. To enable the front door 2 to be opened, in the event'of a power failure, mechanical means are provided for moving the bolt to its unlatching position. This comprises a bell crank 31, Fig. 5 which is pivoted on the jamb face of the frame 30 and which has an upwardly extending arm terminating in a tab 34 which is positioned so that when the push button 5 is depresed the bell crank is rotated. The tab 34 overlies an arm 36 of a pivotally mounted release lever, another arm 38 (see Fig. 2) of which engages a shoulder 39 on the bolt. A second arm of the bell crank is connected to a lever 42 which carries the switch actuator 21 and the lever 42 is connected by a rod 7 to the inside handle 6. Hence movement of either the inside handle or the push button causes the arm 38 of the release lever to move the bolt to unlatching position. No provision is made on the rear door for mechanically unlatching the bolt in the event of power failure. The sill latch 16 on the front door is unlatched when the latch 11 is unlatched by means of a rod 18 which is connected to. the lever 42 carrying the switch actuator 21. The sill latch 16 comprises a frame 80, Fig. 7, which is mounted on the door and this carries a pivoted bolt 81 and a pivoted detent 82. The bolt is bifurcated and engages a striker 87 on the sill 4 of the vehicle. The latch bolt is urged to its unlatching position by a spring 83 and a spring 84 urges the detent towards engagement with latching teeth 85 and 86 on the bolt. When the latch 11 is released the rod 18 pulls the detent from engagement with the bolt 81 and its spring then moves it to its unlatching position. When the door is closed the engagement of the bolt with the striker 87 causes the movement of the bolt to latching position, the detent engaging the bolt under the influence of its spring. The sill latch 17 is identical and the keeper 87 is common to both latches. The sill latch 17 is unlatches by a rod 20, Fig. 3, which is connected to an arm 74 of a pivoted lever 70. The lever 70, Fig. 2, has another arm 72 connected by a rod 10 to the inside handle 9 and a third arm which is connected by a slot 69 to an arm 68 of a bell crank 63. The bell crank 63 is pivoted on the striker frame 64 and has an upwardly extending arm 66 having a tab 67 which is engaged by the push button 8 on the rear door. The actuator 24 for the switches b and j is carried by the arm 74 on the lever 70 so that depression of the push button 8 or rotation of the handle 9 unlatches both the latch 11 and the latch 17. The bolt 12 of the latch 11 is held in either its latched or unlatched positions by an over-centre spring 51 which is connected to the bolt through a pivoted lever 48. In a modification the solenoids 14 and 15 are replaced by a reversible motor which actuates the bolt 12 through a screw jack. The control circuit for the motor uses the same switches as for the solenoid control circuit described above, the motor being caused to rotate in one direction for unlatching and in the opposite direction for latching. The latch 11, Fig. 10, comprises a bolt 12 which is slidably mounted upon a frame 30 and at its end remove from its latching end the bolt has an integral downwardly extending ear 31 which is pivotally connected to a link 33 by a stud 32 which extends through an elongated slot 38 in the frame. The stud 32 forms a mounting means for a helical bolt retracting spring 34 the -inner end of which is anchored to the head of the stud 32 and the outer end of which is anchored to the link 33. The other end of the link 33 carries a rivet 36 which extends through an arcuate slot 37 in the frame 30. The arcuate slot extends downwardly and rearwardly and swinging movement of the link 33 along the slot 37 causes rearward movement of the rear end of the link 33 in the slot 38 and consequent movement of the bolt from latched to unlatched position. The link 33 is shifted between the latched and unlatched position by a drive link 40 which is pivoted to the frame and to an extension of the screw jack. The link 40 has a projection 43 which engages a lug 44 on a link 45 which is pivoted co-axially with the link 40 on the frame. The link 45 is also connected to the link 33 by the rivet 36 and when the link 40 is moved in a counterclockwise direction by extending movement of the screw jack the projection 43 engages the lug 44 and drives links 45 and 33 so that the bolt 12 moves to its unlatched position. The two links 40 and 45 are provided to enable the bolt to be retracted mechanically in the event of power failure. To permit mechanical operation without simultaneous operation of the screw jack there is a triggering pawl 47 pivoted on the link 40. The pawl has a stop tab 49 which when the bolt 12 is in latched position is in engagement with a stop 50 bent from the frame 30. Another stop 51, Fig. 1, on the frame is engaged by the tab 49 when the link 40 moves in counterclockwise direction during the unlatching of the bolt. When the screw jack is extended to swing the link 40 in the counterclockwise direction the tab 49 on the pawl 47 abuts the stop 51 as the unlatching limit position is approached and swings the pawl 47 in a clockwise direction bringing a notched shoulder 52 of the pawl into abutment with a surface 53 of the lug 44. Upon clockwise movement of the link 40 the pawl 47 connects link 40 to the link 45 through the lug 44 and as the links 40, 45 approach the latched position the tab 49 abuts stop 50 and rotates the pawl counterclockwise to move the notch 52 out of engagement with lug 44 so that the bolt 12 can be manually retracted without moving the screw jack. An over-centre spring 54 holds the pawl 47 in either of its two positions. The bolt 12 is held in its latching position by a detent 100 which is pivotally mounted on the frame and which has a blocking portion 102 engaging a notch in the bolt. A spring 103 biases the detent in counterclockwise direction. The detent has an arm 104 extending dnderneath the bolt in the path of movement of a lug 105 projecting from the dr