US1816072A - Electromechanical interlock - Google Patents

Description

July 28, 1931. 1-. BRADY ELECTROMECHANICAL INTERLOCK 3 Sheets-Sheet 1 Filed Feb. 18, 1927 4% M INVENTOR ATTORNEY July 28, 1931. T. BRADY ELECTROMECHANICAL INTERLOCK Filed Feb. 18, 1927 3 Sheets-Sheet 2 1 AM INVENTOR AT'I'ORNEY BY "'u July 28, 1931. T. BRADY ELECTRQHECHANICAL INTERLOCK Filed Feb. 18, 1927 3 Sheets-Sheet 3 VI Q m 6 mm m w M m. m L a V T 5 a m M M 6 a. m F fl AM. mm? M H mu m m w M @W mm m I. v.\ m I w H w into the bracket 8 and are arranged to draw the two sides of the slot 12 toward each other, thereby securing the link 11 to the bracket 8. At its other end, the operating link 11 extends through a slot provided in a bracket 14. Screws 15 secure the link 11 to the bracket 14. The bracket 14 is pivotally connected to a second operating link 16 by means 0t a screw 17. Operating'link 16 extends into a slot provided in a yoke member 20 and is secured to this yoke member by screws '21. Yoke member 20 is pivotally mounted on a pin 22 that is carried by bracket 23 Bracket 23 is secured by screws to a'wall plate 24 which in turn is likewise secured to wall of the hatchway.

Although various arrangements of closing means may be employed for closing the door,'a suitable form of door closing and checking device, indicated as'a whole by the the numeral '28. has been illustrated for this purpose. The door closing and checking device isconnected to operating link 1.6. The details'of the door closing and checking device and the manner in which the deviceis connected to link 16 are clearly shown in'Figure 4. The yoke member 20 is formed with a downwardly extending bifurcated lug'25. A tongue formed ona nut member 26 extends within the bifurcation of the lug and is pivotally connected to this lug by a pin 27 extending through aligned apertures provided in the lug 25 and in the tongue of nutimember 26. Nut

member 26 is threadedon the piston rod of the door closing and checking device 28 and is retained on this piston rod by a lock nut 29. 7 I

The piston rod 30 has a check piston 31 secured to its bottom end for operation within the check cylinder 36. Piston 31 is formed with an aperture 32 extending therethrough from the top to the bottom 1 and at thebottom of this piston the aperture is enlarged to form a valve seat for a ball 33,. Theball 33 is retained in the enlarged portion ofthe aperture by a pin 34. The check piston 31 is rabbeted at .35. The

' lower portion of cylinder 36 is adapted to receive fluid, such as oil, and a filling open- 111g 37 1s provided in this cylinder at the desired liquid level. A threaded'plug 38 is used to close the filling opening37. The

inner surface of the check cylinder 36 is provided with longitudinal grooves that extend from the filling opening 37 to the upper limit ottravel'of the check piston 31. A cap 41'is threaded into the upper end of the check cylinder and serves as a bearing for the pistoirrod 30. A plug 42 is threaded into the lower end of the check cylinder. A gasket 43 is used to seal the connection between the plug 42 and the I check cylinder. Plug'42 has a downwardly a by-pass 44 extending from a point justabove the plug 42 to a point above the filling opening 37. A needle valve 45 is used to adjust the efliective area of the bypass The check cylinder 36 (Figures 1 and 4) has two seniiannular flanges 46 and 47 extending upwardly therefrom. These flanges are arranged to grip a cylindrical casing 48, thereby securing this casing to the check cylinder 36. Casing 48 is composed of two semicylindrical portions and 51. Bolts 49 extend through apertures provided in opposed lugs formed on the flanges 46 and 47 and when the device 28 is assembled these bolts are turned so as to draw flanges 46 and 47 toward each other, thereby binding the two portions 50 and 51 together. The

upper end of the cylindrical casing 48 is closed by an end cover 52 that is divided along a diameter and the two halves thus formed are held together and in gripping engagement with the casing 48 by bolts 53. End cover 52 is provided with a circular aperture through which a sleeve 54 extends. The upper portion. of sleeve 54 is adjustably threaded upon the piston rod 30 and is secured in position'on this rod by a lock nut 55. Nuts 56 are threaded upon the. lower end'ot sleeve 54. A spring clamp 57 rests upon a washer carried by the nuts 56 and grips the upper end of a tension spring 58. The lower end of the tension spring 58 is secured. to the check cylinder 36 by eye-bolts 60 that extend through apertures provided in the check cylinder.

An interlocking bar 64 of rectangular cross-sectiomhas its lower end pivoted upon the pin 27 that connects the yoke member 20 to the piston rod of the door closing and checking device 28. This interlocking bar is also illustrated in Figures 6 and 7 From the pin 27 the interlocking bar 64 extends upwardly through an aperture 65 of rectangular cross-section provided in a guide bracket 66. A locking pin'67 has its ends fixed in the guide bracket66 and its central portion spans the aperture 65. The locking The releasing lever 74 comprises a body portion 75 and three shoulder portions 6, 77 and 78 that extend outwardly from the body portion. When the dooris in its closed position with locking pin 67 in recess 70, the shoulder portion 76 rests against the interlocking bar 64 and forces this bar against the locking pin.

An interlocking switch 87 of any desired form is connected to the releasing lever 74 to be operated'thereby. The details of the interlocking switch chosen for illustration and the manner in which the switch is connected to the releasing lever 7 4 is shown in Figures 1, 3 and 5. The outer end of the shoulder portion 7 6 of releasing lever 74 is bifurcated and an angle member 80 is pivotally connected to this bifurcated end by means of a pin 81. The top of the angle member 80 is 'apertured and the lower end of a rod 82' extends through this aperture and issecured to the angle member by nuts 83.- The upper end ofthe rod 82 extends through an aperture provided in the head of a headed pin 84. Nuts are also used to secure this end of the rod 82 to'the pin 84. Pin 84 is carried by the bifurcated end of the operating lever 85 for switch 87. Lever 85 is pivotally mounted on a pin 86 that is carried by lugs formed on the casing of switch 87. The switch casing is secured by screws to the wall plate 24. A link 88 has one end pivotally connected to the operating lever 85 and its other end pivotally con nected to a switch bar 90. Switch bar 90 is made of insulating material and has an U-shaped contact plate 91 secured to its lower end. Contact plate 91 is arranged to bridge stationary contacts 92 and 93. Contacts 92 and 93 are included in a control circuit for the elevator motor. While contact plate 91 is in engagement with contacts 92 and 93 the elevator motor may be operated to movethe elevator car along the hatchway.

The body portion 75 of releasing lever 74 is provided with an aperture 94 that is of rectangular cross-section (see Figures 6 and 7 A bar 95 has its lower end extending into the aperture 94. A pin 89 extends through aligned apertures provided in the body portion 7 5 and in the lower end of bar 95 and pivotally connects the bar 95 to the releasing lever 74. The upper end of bar 95 is bent at right angles to the centerline of this bar and is apertured to accommodate a rod 96. Rod 96 extends through the aperture in the upper end of bar 95 and has a compression spring 97 surrounding its lower portion. Spring 97 bears at one end against the upper end of bar 95 and at its other end against a spring seat 98 supported on rod 96 by nuts threaded on the lower end of this rod. The upper end of rod 96 has a yoke member 100 threaded thereon.

Yoke member 100 is pivotally connected to a bifurcated end of a lever 101 by a pin 102. Lever 101 is fulcrumed between its ends on a pin 103 extending from a bracket 104. The other end of lever 101 is also bifurcated and is pivotally connected by a pin 106 to the lower end of a link 105. When the door is locked in its closed position the lever 101 bears against a buifer 99 that is carried by an angle member 109. Angle member 109 is secured to the bracket 104. The upper end of link 105 is pivotally connected by a pin 107 to the bifurcated end of one arm of a bell crank lever 108. The bell crank lever 108 is fulcrumed on a pin 110 extending from the bracket 104. The other arm of the bell crank lever has a forked end that carries a pin 111 upon which is rotatably mounted a roller 112. The bracket 104 is secured by screws to the wall of the hatchway.

The elevator car 117 (see Figure 3) carries a retiring cam designated as a whole by character 113. This cam comprises a cam rail 114 connected by links 115 and 116 to the car 117. Links 115 and 116 are pivotally connected to the cam rail by pins 118 and 120 and are also pivotally connectedto the car by pins 121 and 122. The upper end of the cam rail 114 is connected by a yoke 123 to a chain 124. Chain 124 passes over idler sheave 125' and is connected to the shaft 126 of a retiring cam motor 127. An abutment 128 is secured to the cam rail 114 and is arranged to coact with the upper surface of a buffer 130 to determine the extended position of the cam rail. Buffer 130 is carried by a bracket 131 that is secured to the car. An abutment 132 is also secured to the cam rail 114 and is arranged to coact with the lower surface of bufi'er 130 to determine the retired position of the cam rail.

The operation of the locking device is as follows:

Assume that an intending passenger is at the floor illustrated in'Figure 1 and that the car 117 is not in use and is positioned in the hatchway at some other floor, the hatchway door for which is closed. It is to be noted that the intending passenger is unable to open the door 1 as it is locked by the locking pin 67 acting through the interlocking bar 64 and yoke member 20 to prevent movement of operating links 16 and 11.

Upon pressing the hall button (not shown) the intending passenger causes the energization of the retiring cam motor 127 Motor 127 operates-to wind chain 124 upon shaft 126, thereby raising the cam rail 114. As the cam rail 114 is raised the links 115 and 116 cause this member to move inwardly toward the sideof the car until the abutment 132 strikes the buffer 130, thereby effecting the disengagement of the retiring cam from the roller 112 of the operating mechanism member. and rod 82 to the for the door at the floor where the: car is positioned. This results in the locking of this door, as will be explained later in connection with the starting of the car from the floor shown in Figure, 1; V

The car then moves to the intending passengers floor and comes to rest. Although the time that the retiring cam motor is deenergized would depend upon the arrangement of the control circuits, it will be assumed that this motor is deenergized as the car comes to .rest at the floor. The cam rail 114 then fallsunder the action of gravity unwinding the chain 124 from shaft 126 until the abutment 128 carried by rail 114 strikes the buffer 130, whereupon the retiring cam comes to rest. The links: 115 and 116 cause the cam rail 114 to move outwardly as it descends, thereby effecting the engagement of this cam rail with roller 112. The engagement of cam rail 114 with roller 112 causes bell crank lever 108 to turn about the'pivotal pin 110 in a counterclockwise direction as viewed in Figure 1. This motion of hell crank 108 is transmitted through link 105, lever 101, rod 96, spring 97 and bar 95 to the releasing lever 74 and causes the releasing lever to swing upwardly about its pivotal pin 73. k lever 74 starts to swing upwardly the shoulder portion 76 disengages the. interlocking bar 64. The upward movement of shoulder portion 76 is transmitted through angle operating lever of switch 87 and causes this lever to turn about its pivotal pin 86.- This movement of lever85 raises the switch bar to eitect the disengagement of contacts 92 and 93, thus opening the elevator motor control circuit in which these contacts are included. During this movement of the releasing lever 74 and the operation of switch 87, the shoulder ortion 77 of the releasin lever strikes the interlocking bar 64 and turns this bar about its pivotal pin 27 in a clockwise direction until the slot 70 of the bar 64 disengages the. locking pin 67. .The parts are so arranged, however, that the slot 70 does not fully disengage pin 67 until after switch bar 90 disengages contacts 92 and 93. During the movement of the releasing lever, its shoulder portion 78 moves from one side of the'interlocking bar to the other, passing over the beveled end 71 of the bar.

opened by the intending passenger. The links 11 and 16, not being in horizontal alignment when the door is closed, permits the'door, once unlocked, to be moved to open position. During the opening movement the operating links 11 and 16 swing upwardly about their pivots, causing the interlocking bar 64 to move upwardly between the shoulder portions 77 and 78 of releasing lever 74 on one side and shoulder portion As the releasing 76 on the other side. The piston rod 30 and sleeve 54 of the door closing and checking device 28 move upwardly along with the interlocking bar. The upward movement of piston rod 30 causes the check piston 31 to move upwardly in the check cylinder 36. This movement ofthe check piston 31 is not resisted by the liquid in the check cylinder since ball 33 moves away from its valve seat during the upward movement of the check piston and permits liquid to pass from above the piston 31 through the aperture 32 to the space below this piston. The upward movement of sleeve 54 causes the extension of tension spring 58. The positions assumed by the various parts of the locking device at the end of the opening movement are as illustrated in Figure 3.

The passenger may now enter the car and release the door. Upon the door being released, the spring 58 of the door closing and checking device causes the sleeve 54 and piston rod 30 to move inwardly ofthe casing 48, thus effecting the downward swing-v ing of operating links 11 and 16 to close the door. During this movement of these members the interlocking bar 64 moves downwardly until the recess 70 is opposite the locking pin 67. There is no engagement between the recess 70 and the locking in 67 because the shoulder portion 77 holds the interlocking bar 64 away from the pin 67. The check piston 31 moves with the piston rod 30 and toward the end of the closing movement this check piston enters the portion of the check cylinder 36 that is not grooved. As the ball 33 rests against its valve seat during this downward movement, a portion of the liquid in the check cylinder is trapped under the piston 31 and is forced to pass through the restricted by-pass 44. Thus the motion of the check piston and of the connected apparatus, including the door 1, is checked toward the end of the closing operation.

Upon pressing the car button (not shown) corresponding to the landing to which the passenger desires to be taken, the retiring cam motor 127 is energized. This motor operates to cause the chain 124 to wind upon the shaft 126, thereby raising the cam rail 114 as previously described. As the cam rail 114 is retired the weight of the releasing lever 74 and of the mechanism connect- The door 1 isnow unlocked and may be ing lever 74 to the roller 112 causes the releasing lever to swing downwardly about its pivotal pin 73. As the releasing lever commences to swing downwardly the shoulder portion 77 moves away from interlocking bar 64 and this bar, owing to its own'weight, moves toward the locking pin 67 and causes the recess 70 to engage the locking pin, thus locking the door 1. If for any reason the interlocking bar should fail to move into locking engagement with the locking pin,

then further movement of the releasing lever causes shoulder portion 76 to strike this bar and thereby force it into such looking engagement; During the latter part of its movement, the releasing lever causes the switch bar '90 to move the contact plate 91 into engagement with the contacts 92 and 93, thereby completing the elevator motor control circuit in which these contacts are included. These parts are so constructed and arranged that the plate 91 cannot bridge contacts 92 and 93 until after'the recess 70 engagespin 67 to lock the door. The elevator motor thereafter causes the car to be moved toflthe desired floor. Should the retiring cam motor be energized while the car is at a floor with the door'1 open, this motor will retire the cam, permitting the releasing lever to swing downwardly. The motion of the releasing lever is arrested, however, by the shoulder portion 78 engaging the interlocking bar at one side and shoulder portion 76 engaging the interlocking bar at the other side. When the releasing lever comes to rest the contact plate ,91 will still be above the contacts 92 and 93 and, asthe motor control circuit in which these contacts are included is not completed, the elevator motor cannot start and the car remains at rest until the door is closed and locked. I

Undervcertain conditions of operation the roller 112 and bellcrank lever 108may be swung by the retiring .cam to such an ex tent as to cause shoulder portion 78 of the releasing. lever to strike the wall plate 24. Any further movement. of the roller and bell crank lever will merely cause spring 97 to be compressed without injuring the door locking device. 7

It is to be noted that when the door is locked the interlocking bar 64 is held in firm engagement with the locking pin 67 by the weight of the releasing lever combined with that of the mechanism connecting this lever to the bell crank lever 108.

The door operating mechanism shown in Figures 8 to 11 inclusive is illustrative of mechanism suitable for hatchway doors of elevator systems of the type wherein the elevator car is provided with an operator. The operating links 165 and 166 for the door 167 are arranged in a manner similar to that described for operating links 11 and 16 above described. With the door in closed position, however, the links 165 and 166 are horizontal and in alignment. Link 165 is provided with a handle 133. The interlocking bar 129 .is pivotally connected to the yoke member 168 into which the link 166 extends and tothe piston rod for the door closure and checking device, as previously described for interlocking bar 64. The interlocking bar cooperates with the locking pin 139 ;to lock and unlock the door.

The releasing lever 135 instead of being actuated by a motor operated retiring cam is arranged to be mechanically operated by the car operator. In order to carryout this mechanical operation, a pedal 136 is positioned in the car where it will be convenient for actuation by the operators foot. Pedal 136 has a shank that extends through an aperture provided in one arm of a bell crank lever 137. Lever 137 is pivoted on a pin carried by a bracket 159. Nuts 138 are threaded on the shank oi pedal 136 and abut this arm or" the lever 137. The other arm of lever 137 is connected by an adjustable link 140 to one arm of a lever 141. other arm of lever 141 is connected by an adjustable link 142 to one end of a tension spring 143. The other end of spring 143 is connected to a pin 144 extending from the underside of the car floor 145. Lever 141 is secured to a shaft 146 by set screws. Shaft 146 extends through bearings 147 .and 148 formed on a casting 150. Casting 150 is attached by bolts 151 to an angle member 152 that is secured to the underside of the car floor 145. A lever 149 of a retiring cam is pinned on the shaft 146 and has its outer end pivotally connected to the lower portion of a cam rail 153. The upper portion of cam rail 153 is pivotally connected to a link 154 that in turn is pivotally connected to a.

plate 155 formed on the casting 150. The cam rail 153 is arranged to cooperate with a boss 156 formed on a lever 157. A square shaft 158 extends through an aperture of square cross-section provided in the hub of lever 157. Shaft 158 also extends through similar apertures formed in twolevers 160 and 161. Levers 157, 160 and 161 are retained on shaft 158by set screws. Lever 161 is pivotally supported on a pin 162 carried by a bracket 163 that is secured to the hatchway door sill. Lever 1 60 is pivotally connected to a vertically extending link 164. Link 164 is pivotallyconnected to the releasing lever 135.. v

The tension spring 143 acts through lever 141 shatt 146 and lever 149 to hold the cam rail 153 in its retired position and away from the boss except when the cam rail is held in its extended position by the action of the car 0 aerator. With the cam rail 153 in its retiree position the pedal 136 extends upwardly into the car.

hen the car is at a landing with the door closed and locked, should the operator desire to open the door he pushes the pedal 136 downwardly into the position illustrated in Figure 9. This movement of pedal 136 is transmitted by nuts 138 on the shank of this The iao

causes lever 157 together with levers 160 and 161 and shaft 158 to turn as a unit about thefpin 162. The movement 'of lever 160 causes link 164 to move upwardly, thereby effecting the upward swingingof releasing 87 and thereafter the disengagement of interlocking bar 129 and unlock the door.

The operator may now open the door by means of handle 133. Owing to the fact that links 165 are in horizontal alignment, the toggle jointbetween these links must be broken as a part of the door opening operation. This toggle joint is automatically broken by pulling on ,the handle 133. This arrangement, however, prevents the unwarranted opening of the door, as by intending passengers from the outside, even though interlocking bar 129 and locking pin 139 locking pin 139 to are disengaged, for the'force applied by such person to open the through links 165 and 166 in a straight line to wall plate 134. Thus, as there is no force tending to swing the operating links upwardly about their pivots, the toggle joint is not broken and the door can not be opened.

The operator by releasing the handle 133 permits the door closing and checking dedoor is transmitted 'vice to operate to close the door as previously described in connection with the arrangement illustrated in Figures 1 to 7 inclusive. Upon his releasing the pedal 136 the tension, spring 143 acts through the link 142 to swing lever 141 in a clockwise direction as viewed in Figure 9. This movement of lever 141 is transmitted through shaft 146 and lever 149 to the cam rail 153 and causes this rail to be retired; This movement of lever 141 is also transmitted through.

link 140 and bell crank lever 137 to the pedal 136 and causes the pedal to move upwardly to its normal position in the car. The retiring of the cam rail permits the releasing lever 135 to turn, under the action of gravity, about its pivotal pin in a direction to eflect the locking of the door. Continued movement of the releasing lever after the door is locked causes the switch 87 to close, thereby permitting operation of the elevator; Should the pedal 136 be released while the door is still open, the releasing lever 135 will fall until its shoulder portions engage the interlocking bar 129 in the 111311118X described in connection with the arrangement, illustrated in Figures 1 to 7 inclusive. Under such conditions the switch 87 cannot close and the elevator cannot be operated until after the door has been closed and locked.

It is to be understood that a retiring cam cooperate with said arrangement and operating motor, such as illustrated in Figure 3, may be employed in conjunction with the operating linkage illustrated in Figures 8 to 11 inclusive instead of the pedal arrangement shown.

' Also, it is to be understood that the electromechanical interlock may be applied to other forms of door operating mechanism, regardless of whether this mechanism is operated by the application or" manual or other power.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limitingsense. I

What is claimed is:

1. In an elevator system, a-hatchway door, linkage connected to said door for effecting the operation of the door, a stationary pin, a bar connected to said linkage and arranged to engage said pin, with the door in closed position, to hold the linkage in fixed position thus locking the door. a

2. In an elevator system, a hatchway door, door closing means, linkage connecting said door closing meansto the door, a bar connected to said linkage, a member arranged to cooperate with said'bar, and means for effecting the movement of the bar into 00- operating position with said member to lock the door in its closed position and for effecting the movement of the bar out of cooperating position with'said member to unlock'the' door. I

3. In an elevator system, a hatchway door, linkage connected to said door for effecting the operation thereof, a locking pin, an interlo-cking bar pivotally connected" to said linkage and arranged to cooperate with said pin, and a releasing lever, said releasing lever being arranged to move said nterlocking bar into engagement with saidlocking' pinto prevent the operation of said door.

, 4. In an elevator system, a hatchway door, door closing means, linkage connecting said door closing means to the door, a stationary locking pin, an interlocking barpivotally connected to said linkage and arranged to pin, and a releasing lever adapted to cooperate with said interlocking bar, said releasing lever being arranged either to cause said interlocking bar to move into engagement with the locking pin and thereby effect the locking of the door or to cause said interlocking bar to move out of engagement with the locking pin and thereby effect the unlocking of the door.

5. In an elevator system, a hatchway door, door closing means,

locking pin, an interlocking bar pivotally connected to said linkage arranged to cooperate with said pin, a releasing lever adapted to cooperate with said interlocking bar, and means for operating said releasing lever, said releasing lever, during its operation causing the interlocking bar to move out of cooperative position with the locking pin thus effecting the unlocking of the door. 6. In an elevator system, a hatchway door, linkage connected to said door for effecting the operation of the door, a stationary looking pin, an interlocking bar pivotally connected to said linkage and arranged to cooperate with said interlocking bar, a releasing lever, and means for operating said releasing lever to cause this lever to move the interlocking bar into or out of cooperative engagement with the locking pin to efiect the locking or unlocking of the door; 7. In an elevator system, a hatchway door, operating linkage for said door, an interlock switch having an operating member, a pivoted releasing lever connected to said member and having a projection formed thereon, a stationary locking pin, an interlocking bar pivotally connected to said operating linkage and disposed in the path of the projection on said releasing lever, said bar having a recess for engaging said looking pin with the door closed to lock said linkage against operation, and means for moving said releasing lever about its pivot to cause the opening of said switch, said releasing lever projection engaging said interlocking bar during the movement of the releasing lever to cause the interlocking bar recess to disengage said pin after the opening of said switch, thus unlocking said linkage to permit the opening of said door, said releasing lever, during its return movement with the door closed, causing the locking of said linkage and thereafter the closing of said switch.

8. In an elevator system, a hatchway door, operating linkage for said door, an interlock switch having an operating lever, a releasing lever having projections thereon, and connected to said operating lever, a stationary locking pin, an interlocking bar pivotally connected to said operating linkage and disposed in the path of the projections on said releasing lever, said bar being provided with a recess, one of said projections holding said interlocking bar so that the recess therein engages said locking pin with the door closed to lock said linkage against operation, and means for moving said releasing lever about its fulcrum to cause the switch operating lever to open said switch, another of said projections engaging said interlocking bar during the movement of the releasing lever to cause the interlocking bar recess to disengage said lockingv pin after the opening of said switch, thus unlocking said linkage to permit the opening of said door, said releasing lever, during its return movement, causing the interlocking bar recess to engage said locking pin to lock said linkage, provided the door is closed,

lever having projections thereon, and connected to said operating lever, a stationary locking pin, an interlocking bar pivotally connected to said operating linkage and disposed in the path of the projections on saic releasing lever, said bar being provided with a recess, one of said projections holding said interlocking bar so that the recess therein engages said locking pin with the door closed to lock said linkage against operation, and means for moving said releasing lever about its fulcrum to cause the switch operating lever to open said switch, another of said projections engaging said interlocking bar during the movement of the releasing lever to cause the interlocking bar recess to disengage said locking pin after the opening of said switch, thus unlocking said linkage to permit the opening of said door, said one and still another of said projections cngaging said interlocking bar during the return movement of the releasing lever to stop this lever, should the door be open, and thereby prevent the closing of said switch.

10. An electromechanical interlock tor hatchway doors provided with operating mechanism comprising, a switch, a stationary pin, a bar pivotally connected to the door operating mechanism, said bar having a recess and being biased to cause said recess to engage said pin and lock the door in its closed position, and a releasing lever associated with said bar and operatively connected to said switch, said releasing lever being movable to cause the operation of the switch and thereafter the disengagement of the recess from the pin to unlock the door.

11. An electromechanical interlock for hatchway doors provided with operating mechanism comprising, a switch, a stationary pin, a bar pivotally connected to the door operating mechanism, said bar having a recess and being biased to cause said recess to engage said pin and lock the door in its closed position, a pivoted releasing lever associatedwith said bar and operatively connected to said switch, said releasing lever engaging said bar in one position to maintain said recess in engagement with said pin, and means for causing pivotal movement of said releasing lever from said one position and also for causing the return of said releasing lever to said one position, said releasing lever, during its movement from said one position, causing the opening of said switch and thereafter the disengagement of the recess from the pin to unlock the door to permit the opening thereof and, during its return to said one position with the door closed, permitting the engagement of said recess and said pin to lock the door and causing the closing of said switch, said lever engaging said bar during said return movement in the event that said recess is not in engagement with said pin to insure the engagement of the recess and pin and the 100king of the door prior to the closing of said switch.

In testimony whereof, I have signed my name to this specification.

THOMAS BRADY.

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