US2804296A

US2804296A - Elevator door operator

Info

Publication number: US2804296A
Application number: US510173A
Authority: US
Inventors: Arthur E Raque
Original assignee: WATSON ELEVATOR Co Inc
Current assignee: WATSON ELEVATOR Co Inc; WATSON ELEVATOR COMPANY Inc
Priority date: 1955-05-23
Filing date: 1955-05-23
Publication date: 1957-08-27
Anticipated expiration: 1974-08-27

Description

Aug. 27, 19 57 A. E. RAQUE ELEVATOR- DOOR OPERATOR e Shee tsSheet 1 Filed May 25, 1955.

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4271/02 5 PQQUE HTTOR/VEY ELEVATOR DOOR OPERATOR Arthur E. Raqu, Demarest, N. J., assignor to Watson Elevator Company, Inc., New York, N. Y., a corporation of New York Application May 23, 1955, Serial No. 510,173

14 Claims. ((Zl. 268-51) My invention relates to an elevator door operator and more particularly to an improved elevator door operator for controlling the opening and closing movements of an elevator door whereby the door will approach its limit positions at comparatively slow speeds.

It is desirable in all elevator cabs, and especially desirable in the case of cabs for automatic elevators, that the last portion of the closing movement of the elevator door be accomplished at a relatively slower speed than that of the initial portion of the door closing movement. This prevents slamming of the elevator door and reduces the possibility of injury to persons using the elevator or damage to the door or the door operator parts. It is, moreover, desirable that the last part of the opening movement of the door be accomplished at a relatively slower speed than is the initial movement of the door in opening. This prevents jarring of'the door at the open limit position. In most of the elevators of the prior art, the power to the elevator door drive is shut oif at a point just short of the open limit position, and the door is permitted to coast to a stop, with the result that the door and the door operator parts are jarred to a stop. In my Patent No. 2,572,196, dated October 23, 1951, I have disclosed an elevator door operating mechanism which provides a relatively slower speed for the final portion of the movement of the door to its open limit position and for the final portion of the movement of the door to its closed limit position. I have now invented an elevator door operator which represents an improvement on the construction disclosed in the said patent. My improved elevator door provides a smooth and silent transmission of power from the prime mover to the door. It employs no gears for speed change and includes no chain drive which becomes noisy when it wears after extended use. My operator has a belt and pulley drive and speed change system which is quiet in operation and will remain so for years of constant use. My improved door operator provides the same torque at both high and low speeds. This torque is sufficient to operate both the elevator car doors and the hoistway doors. My improved elevator door operator is provided with a belt nited States Patent drive in which a large portion of the drive belt is in contact with the belt drive pulleys whereby frictional contact is made over almost the entire length of the drive belt to reduce slippage. The magnitude of the force exerted can easily be adjusted by changing belt tension. Myimproved system is flexible in use in that the same assembly may be used for a wide range of door travels. The only adjustments which are necessary in various installations are the provision of longer tracks and the adjustment of the settings of the limit switches of the assembly. Since the door moving force depends on friction, the same force will be applied throughout the entire door travel. My door operator is quieter in operation than the door opening mechanisms of the prior art. 7

One object of my invention is to provide an improved elevator door operator for driving an elevator door at a relatively slower speed during the respective terminal portions of its movements than during corresponding initial portions of its movements, both on opening and closing of the door.

A further object of my invention is to provide an improved elevator door operator which delivers a torque sufficient to operate both the elevator car doors and the elevator shaft doors.

Another object of my invention is to provide an improved elevator door operator having a belt'drive in which a large portion of the length of the drive belt is in contact with the drive pulleys.

A still further object of my invention is to provide an elevator door operator which is flexible in application so that the same assembly may be used for a wide range of amplitudes of door motion with few and minor adjustments.

Other and further objects of my invention will appear from the following description.

In general my invention contemplates the provision of an elevator door operator including a high-speed drive and a low-speed drive, both of which may be driven from a common prime mover. Any convenient mechanism may be employed for operating the elevator door from the respective drives. For example, I may employ a drum and cable arrangement which is driven in one direction to open the elevator door and is driven in a reverse direction to close the door. I provide means by which the cable drum drive means may be connected either to the door operator high-speed drive or the door 3 I operator low-speed drive. When the elevator car carrying the doors and opener arrives at a floor, a main control relay is actuated to energize the driving prime mover in a direction to open the elevator door. The driving of the prime mover in this direction urges the connecting means to engage the cable drum drive means with the high-speed drive. I provide automatic control means operable by the cable drum for urging the connecting means to connect the slow-speed drive with the cable drum when the elevator door approaches the fully open position. When the door arrives at its opening limit position,'a limit switch interrupts the elevator drive motor circuit to stop the motor. After a predetermined time, operation of a relay reverses the circuit of the opener drive motor to drive the cable drum in a direction to close the doors. This rotation of the cable drum actuates the connecting means to connect the fast drive with the cable drum. As the door approaches the fully closed position, a limit switch breaks the prime mover circuit and the car is ready to move up or down in its shaft.

In the accompanying drawings which form part of the instant specification and which are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

Figure 1 is a fragmentary front elevation of an elevator car equipped with my improved door operator, showing the arrangement of the operator with relation to the car door.

Figure 2 is a fragmentary front elevation of my improved elevator door operator drawn on an enlarged scale.

Figure 3 is a fragmentary top plan of my improved elevator door operator drawn on an enlarged scale and taken along the line 3-3 of Figure 2.

Figure 4 is a sectional view of my improved elevator door operator drawn onan enlarged scale and taken along the line 44 of Figure 1.

Figure 5 is a sectional view of my improved elevator door operator drawn on a greatly enlarged scale and taken along the line 55 of Figure 3.

Figure 6 is a fragmentary view, drawn on a greatly enlarged scale, of the operating arm latch means of my improved elevator door operator.

Figure 7 is a fragmentary perspective view of my improved elevator door operator drawn on an enlarged scale.

More particularly referring now to Figures 1 and 4 of the drawings, the elevator cab, indicated generally by the reference character 10, with whichrny improved ele vator door operator is associated, supports a structural member, indicated generally by the reference character 12, by any convenient means adjacent its top front. 'The' member 12 includes a pair of end brackets 14'and '16 which support a top angle iron 18' and a bottom angle iron 20. The lower angle iron 20 supports a

pairof guide rails

22 and 24. The

guide rails

22 and 24 are held to the depending flange of the angle iron 20 by means of bolts 26 and are maintained in spaced relationship by

spacers

28 and 30 carried on the shanks. of. the bolts 26. doors which I shall term respectively a fast door 32 and a slow door 34. The fast door 32 is supported from the guide rail 22 by means of a pair of hanger assemblies, indicated generally, respectively, by the

ref erence characters

36 and 38. Each of the

assemblies

36 and 38 includes a housing 40 in which a roller 42 is pivotally mounted on a shaft 44. The arrangement is such that the roller 42 of each of the hanger assemblies movably rests on the rail 22. Each of the housings 40 is secured to the door 32 by means of a pair of threaded studs 46 extending into the lower flange of the housing and secured therein by nuts 48. bracket 50 by means of nuts 54. Bracket 50 may be attached to the top of the elevator door by any convenient means, such as bolts 52. The

respective assemblies

36 and 38 maybe secured to each other by a structural member 56 extending between the housings 40 and secured thereto by means such as machine screws 58. It will be appreciated that the

hanger assemblies

36 and 38 provide a means by which the fast door 32 is suspended from rail 22 for movement therealong.

In order to support the slow door, I provide a pair of hanger assemblies, indicated generally, respectively, by the

reference characters

60 and 62.

Hanger assemblies

60 and 62 are in all respects similar to the

assemblies

36 and 38 and like parts of these assemblies have been indicated by the same reference characters as were used for the same parts in the assemblies 36 and- 3'8. The studs 46 of the

assemblies

60 and 62 secure the respective hanger assemblies directly to the top of the slow door through

brackets

64 and 66. The respective slow

door hanger assemblies

60 and 62 are connected by a plate 68 fixed to the assemblies by means of screws 70. As can be seen by reference to Figure 1, the plate .68 extends to the right beyond the assembly 36 associated with the fast door 32.

Referring now to Figures 1, 4 and 5, a drive drum, indicated generally by the reference character 72, is retained on a shaft 74 by"means of a washer 76 held to the shaft 74 by a bolt 78 threaded into a recess 80 in the shaft end. A key 82 provides a means by which the shaft 74 is coupled with the drum 72 for rotation therewith. Shaft 74 is rotatably supported in a bearing 84 retained in a recess in one arm 86 of a U-shaped bracket, indicated generally by the reference character 88, by means of a retaining ring 90 secured to the arm 86 by machine screws 92. The bracket 88 is fastened by bolts 94 to the horizontal flange of the angle iron 18 of the structural member 12. Bracket 88 includes a second arm 96. Drum 72 is arranged, when driven, to drive the door opener cable 98 which is passed around the grooved portion 100 of the drum 72. The portion of cable 98 extending to the left from drum 72, as viewed in Figure 1, passes around a first idler pulley 102 rotatably mounted on a pin 104 carried by a U-shaped idler bracket 106 fixed to the bracket 14 by means of a bolt-108. After passing aroundsheave 102, cable 98 passes around a pul- The elevator door assembly includes two.

Studs 46 are secured to a ley 110 pivotally mounted on a shaft 112 fixed by any convenient means to the fast door pulley support plate 56. From pulley 110 cable 98 passes around a pulley 114 pivotally carried by a shaft 116 supported on the slow door pulley support plate 68. Cable 98 then extends around a second pulley 118 rotatably mounted on a pin 120 carried by the portion of plate 68 which extends ,to the right of slow door hanger assembly 62 as viewed in Figure 1. After passing around the pulley 118, cable 98 is secured bya fitting 122 to the bracket 14.

The portion of cable 98 extending to the right from drum 72, as viewed in Figure 1,.passes around an idler sheave 124 rotatably mounted on a pin 126 carried by a U-shaped sheave support bracket 128 secured to bracket 16 by a bolt 130. After passing around sheave 124 this portion of cable 98 travels around a pulley 132 rotatably mounted on a pin 134 carried by supporting plate 56. From the pulley 132 cable 98 passes to a fitting 136 by means of which the cable is secured to the bracket 16.

When drum 72 is driven'in one direction or the other, cable 98 will be driven to open or to close the elevator doors. Advantageously, the pulley arrangement just described provides such mechanical advantage that the fast door 32 is driven at twice the speed at which the slow dooris driven. It is to be understood that the arrangethe direction of rotation of drum 72 is reversed,.the

t doors close.

I provide both a fast and a slow drive for the drum 72.

As can be seen by referenceto Figure 4, drive pulley sup- 'bolts 144. The upper end of bracket 140 supports a motor platform 146 by means of bolts 148. Platform 146 carries a drive motor 150 having a shaft 152 to which a pulley- 154 is fixed for rotation therewith.

As can be seen by referenceto Figures 1, 2, 4 and 7, pulley,154 drives a belt 156 which drives a sheave 158. Sheave 158 is fixed on an extended hub portion of a slow speed pulley 174 which is rotatably mounted by a bushing 162 or the like on a shaft .160 which is fixedly supported inbracket 140. It will be appreciated that when sheave 158 is driven, the slow speed pulley 174 alsois driven, though with a lower peripheral speed. Belt 156 also drives a second pulley 164 rotatably supported by a bushing 168, or theh'ke, on a shaft 166 carried by bracket 140. Drum 72 includes a sheave 170 adapted to be driven by a belt 172. Belt 172 may alternately be engaged, by means 'to be described hereinafter, with the slow speed pulley 174- or with a high speed pulley 176. Pulley 176 is formed integrally with the pulley 164 and is likewise rotatably supported on shaft 166 by bushing 168. When the 'belt 172 is engaged with the pulley 176, drum 72 is driven at a high speed. When thezbelt 172 is engaged with the pulley 174 on shaft 160, the belt will be driven at a low speed. The speed ratio between pulleys 174 and'176 is determined by the relative diameters of the respective sheave 158 and pulley 164. Since both these pulleys are driven by the same belt 156, the

linear speed atthe periphery of each of the sheave 158 and pulley 164 will be the same. However, since sheave 158 has a diameter which is much larger than-the diameter of pulley 164, pulley 174 will bedriven at a correspondingly slower speed than will the pulley 176.

Referring now to Figures "1, 2 and 7, in order to engage the belt 172 with either the slow pulley 174 or the fast pulley 176, I.provide a beltshifting arm 178 fixed on a shaft 180 rotatably mounted in a bushing 1.82 carrie y bracket 140. Arm 178 rotatably carries a pulley'184 on one end thereof by means of a pin 186. It will readily be appreciated that when arm 178 is in the up position as viewed in Figure 7, pulley 184 urges belt 172 to a position where it is engaged with the fast drive pulley 176. The limit of this up position is determined by a stop 188 secured to the bracket 140 in a position to engage the end of arm 178 remote from pulley 184. The down position of pulley 184 is determined by a second stop 190 fixed by any convenient means to the bracket 140. When pulley 184 occupies its down position, indicated in broken lines in Figure 2, belt 172 engages the slow drive pulley 174. It will readily be understood that when belt 172 is engaged with pulley 176, it does not engage pulley 174. Similarly, when belt 172 engages pulley 174, it is disengaged from pulley 176. Owing to the inherent elasticity of belt 172, arm 178 has a toggle action in moving between its fast and slow drive positions which tends to resist a shifting of the arm 178.

When the elevator cab arrives at a floor, a switch (not shown since it is known to the art) on the main motor control is operated to energize motor 150 to drive shaft 152 in a direction to open the doors. In order to open the doors shaft 152, and thereby shaft 74, are rotated in a counterclockwise direction as viewed in Figures 1 and 2 and in a clockwise direction as viewed in Figure 7. Since belt 156 provides a driving engagement between pulley 154 and the

pulleys

158 and 164, these pulleys will be driven in the same direction as shaft 152. At the time the elevator c-ab arrives at a floor pulley 184 is in the down or slow drive position as viewed in Figure 7 wherein the belt 172 engages pulley 174. The belt shifter pulley has been left in this position at the end of the preceding operation, as will be explained hereinafter. When shaft 152 drives belt 156 in a direction to open the doors, belt 172 is driven by virtue of its engagement with pulley 174 in a direction to urge the belt shifting pulley 184 from the down or slow drive position to the up or fast drive position at which the belt 172 engages pulley 176. When belt 172 thus engages pulley 176, the cable 98 is driven in a direction to open

doors

32 and 34 with the door 32 traveling at a speed which is greater than that at which door 34 travels. This faster rate of travel of door 32 is, as has been explained hereinabove, the result of the mechanical advantage provided by the door opening pulley system.

Referring now to Figures 6 and 7, my operator includes a latch 192 frictionally carried by a second extended portion of the hub of pulley 174 on the other side of pulley 174 than that on which sheave 158 is mounted. As will be explained in detail hereinafter, during a portion of the closing movement of the door, latch 192 engages a pin 194 to retain pulley 184 in the up or fast drive position against the belt action. It is desirable, however, that this latch be held out of engagement with the pin 194 when pulley 184 is the up or fast drive position during the opening of the doors. This is accomplished by virtue of the frictional engagement of the latch with the hub of the slow pulley 174. As this hub rotates in a clockwise direction as viewed in Figure 7 during the opening of the doors it carries the latch along with it. In order to limit the movement of the latch in either direction as pulley 174 rotates, I fixedly mount a disk 196 carrying a stop pin 198 on the shaft 160. As latch 192 is carried along with the hub of pulley 174 in a clockwise direction, a tangential extension 200 on latch 192 engages pin 198 to arrest the movement of the latch. When latch 192 is so arrested, the hub of pulley 174 slips with respect to the latch.

As can be seen by reference to Figure l, a bracket 282 secured to plate 56 by screws 204 carries a cam roller 266 by means of a pin 208. When the doors are in closed position, roller 206 engages the operating arm 210 of a switch 212 carried by angle iron 18. When so eng-aged, operating arm 210 closes the switch through a button 214. As the doors begin to open roller 206 releases the arm 210 so that it may be actuated by a spring 216 to permit the switch 212 to open. This switch 212 is a safety switch which breaks the normal elevator car operating circuit.

It is desirable that the elevator door drive be shifted to a slow drive position in accordance with my invention as the door approaches its fully open position in order that the door not be slammed open and possibly damaged. In order to accomplish this, I provide means for urging arm 178 against the action of the drive belt 172 to a position at which belt 172 engages the slow drive pulley 174 and disengages the fast pulley 176. Referring now more particularly to Figure 5, the shaft 74 which is rotatably supported in arm 86 of bracket 83 by bearing 84 has a friction disk 218 fixed thereon for rotation therewith by means of a pin 220. Rotatably mounted on a bushing 222 on shaft 74 adjacent the friction disk 218 is an idler member 224. A second friction disk 226 is mounted on shaft 74 for rotation therewith and axial movement therealong by means of a spline or key 228. It will readily be appreciated that if disk 226 is urged toward disk 218, the idler 224 will be clamped between the two friction disks so as to be driven with the shaft 74. Also carried on shaft 74, by means of key 228 is a screw or worm member, indicated generally by the reference character 230. The end of this member adjacent the disk 226 is formed with a head 232 having a number of recesses 234 in its face adjacent disk 226. Springs 236 are disposed within the recesses 234 to bear against recess portions 238 which are formed on the disk 226. It will readily be appreciated that if worm 238 moves to the right as viewed in Figure 5, springs 236 exert a clamping pressure against idler 224 to clamp that member to disk 218 so that it will rotate with shaft 74. The head 232 of the worm 230 is connected with disk 226 by means of bolts 248 disposed in countersunk bores 242 in head 232 and screwed into holes 244 in disk 226. Nuts 246 hold the bolts in position with relation to disk 226. As worm 230 moves to the left as viewed in Figure 5, disk 226 is carried away from member 224 by the connection between head 232 and disk 226 provided by bolts 240. As worm 230 moves to the right as viewed in Figure 5, springs 236 urge disk 226 into engagement with member 224 to clamp the member between disk 226 and disk 218. The countersunk bores 242 in head 232 permit relative movement between head 232 and disk 226 in the clamping direction to ensure high clamping pressure. An internally threaded cylindrical member 248 is retained in an opening 258 provided in the arm 96 of bracket 88 by means of retainers 252 secured to arm 96 by bolts 254. The arrangement is such that the end of worm 230 remote from head 232 threadably engages the internal threads of the bore member 248. It will readily be appreciated that as shaft 74 turns, worm 230 also turns. By virtue of the engagement of the threads of worm 230 with the internal threads of the member 248, worm 230 will be moved in one direction or the other along the shaft 74 depending upon the direction of rotation of shaft 74. The direction of rotation of shaft 74 during the opening of the doors is-such that worm 230 moves from the left in Figure 5 towards the right. The arrangement is such that when the doors approach their fully open position, worm 238 has traveled to a position at which springs 236 clamp the member 224 between

disks

226 and 218. When this occurs, member 224 is clamped to rotate with shaft 74 in a clockwise direction as viewed in Figure 7.

As can be seen by reference to Figures 2, 3, 5 and 7, the member 224 carries a depending lug 256 to which a fitting 258 is pivotally connected by a pin 260. A connecting rod 262 is threaded at one end in fitting 258 and at the other end is pivotally connected to a crank 264 by means of a fitting 266 and a pin 268. The end of crank 264 remote from pin 268 is fixed on shaft for rotation therewith. Referring now to Figure 7, when '7 shaft 74 is driven in a clockwise direction during' the opening; of the door, the clamped member 224 is also driven in a clockwise direction to push connecting rod 262 to the left as viewed in the figure and to rotate crank 264 and shaft 180 in a counterclockwise direction. Since arm 178' is fixed on shaft 180 for rotation therewith, the rotation of shaft 180 under this action of member 224 rotates arm 178 until pulley 184 engages belt 172 with the slow speed pulley 174 and disengages it from the fast drive pulley 176. This is the broken-line position shown in Figure 2. As can beyseen by reference to Figures 3 and 7, in order to interrupt the circuit of the operator drive motor 150 when the elevator door has arrived at the fully open position, I provide an opening limit switch 270 which may conveniently be carried by a bracket 272 supported on the iron 18. A threaded rod 274, supported between

arms

86 and 96 of bracket 88 and secured thereto by nuts 276, pivotally supports the actuating member 278 associated with switch 270. A split collar 280 clamped to the head 232 of worm 230 adjacent disk 226 by means of a nut 282 carries cam roller 284 on a pin 286. The arrangement is such that when the doors have arrived at their fully open position, worm 230 has moved to a position at which roller 284 engages the actuator 278 to operate mercury switch 270 to interrupt the elevator door opening drive circuit.

Inthe event my door operator is employed on an automatic elevator, a time delay relay (not shown) reverses the circuit of motor 150 after a predetermined time interval to drive cable 98 in a direction to close the doors. When belt 156 is driven'in a direction to close the doors, itdrives the slow drive pulley 174 in a counterclockwise direction as viewed in Figure 7; that is, a clockwise direction as viewed in Figures 1 and 2. The pulley 176, the pulley 184, and the shaft 74 all will be driven in the same direction as pulley 174; When the pulleys are so driven, the action of belt 172 tends to pull arm 178 down to the slow drive position, as viewed in the figures. Since the arm has been left in this position at the end of the door opening, the belt action tends to retain the arm in this position. It will be remembered, how ever, that the member 224 was left clamped between

friction disks

226 and 218 at the end of the door opening operation. Consequently, when the direction of drive is reversed to close the doors, member 224 moves arm 178 against the action of the belt 172 to a position where belt 172 engages the fast drive pulley 176. I provide means for preventing the movement of arm 178 to the slow drive position when member 224 is unclamped as worm 230 moves to the left as the doors close. Latch 192 which was frictionally held by the hub of pulley 174 out of engagement with pin 194 during the opening of the doors is frictionally urged in the opposite direction by the hub of pulley 174 when the motor reverses so that it engages pin 194 to hold arm 178 in the fast drive position against the action of the belt 172. This movement of the latch 192 is limited by the engagement of pin 198 with a second tangential extension 288 formed on the latch. From the foregoing explanation it will be seen that the initial movement of the doors in closing is under the influence of the fast drive. As has been explained hereinabove, it is desirable that the terminal portion of the movement of the doors be under the action of the slow drive.

I provide means for releasing the latch 192 as the doors approach the fully closed position to permit belt 172 to move roller 184 to the slow drive position where the belt 172 is engaged withpulley 174 and disengaged from pulley 176. As can be seen by reference to Figures 3, 6 and 7, I mount a crank 290 on a shaft 292 for rotation therewith. Shaft 292 is rotatably supported in a bushing carried in bracket 140. Crank 290 carries a pin 294 in a position to engage the extension 288 of latch 192. As can be seen by reference to Figure 7, if shaft 292 is rotated in a counterclockwise direction, pin 294 engages extension 288 to move latch 192 on the hub of pulley 1714in'a directiontorelease pin 194 and permit the belt action to bring pulley 184 to the slow drive position where belt" 172- engages the slow drive pulley 174. In order toaecornplish thismovement of shaft 292 l mount a crank 296 on shaft 292 for rotation therewith. Aconnecting rod 298-is pivotally connected by a pin 300 at one end to crank 296'. 'The other end of rod 29 8 is connected by a pin 302 to a crank 304. Crank 304 is carried by: a sleeve 306 for rotation therewith. Sleeve 306, in turn, is rotatably mounted on a rod or stationary shaft 308 extending between the

sides

86 and 96 of the bracket 88. Nuts 310 retain rod 308 in the

sides

86 and 96 of the bracket 88. It will readily be appreciated that when sleeve 306 is turned in a counterclockwise direction as viewed in Figure 7, shaft 292 also will be turned in a counterclockwise direction. I provide an operating means for turning sleeve 306 in a counterclockwise direction at the proper point in the closing movement of the doors .to connect the door drive with the slow drive pulley.

This mechanism includes a second crank 312 mounted on sleeve 306 for rotation therewith. An actuating lever 314 is connected at one end to crank 312 by a pin 316. The other end of lever 314 is pivotally carried by a rod 318 fixed between the

sides

86 and 96 of bracket 88 by nuts 320. An adjustable fitting 322 may be employed to position lever 314 along the shaft 313. Also, to permit this movement, the crank 312 may be provided with a hub portion by means of which it is adjustably mounted on sleeve 306. A set screw 324 may be employed properly to position crank 312.

Referring now to Figures 3, and 7, in order to actuate the lever 314 to operate crank 312 at the proper point in the closing movement of the doors, I provide a cam roller 326 pivotally carried on a pin 328 in a split collar 330 clamped on the worm 230 by means of a bolt 332. It will be remembered that as the doors close worm 230 travels to the left, as viewedv in Figure 5. When the worm travels a predetermined distance, ,cam roller 326 engages a bearing portion 334 carried by lever 314. When this occurs lever 314 is moved downwardly as viewed in Figure 7 to pivot in a counterclockwise direction about shaft 318. This action operates crank 312. to pivot sleeve 306 in a counterclockwise direction. about the shaft 303. As a result of this movement of the sleeve, connecting rod 298 is moved generally to the right: as viewed in Figure 7 to pivot shaft 292 in a counterclockwise direction. As the action of lever 314 I adjustably mount an eccentric step 336 on a shaft 338 fixed between the

sides

86 and 96 of bracket 88 by nuts 340'. It will readily be appreciated that the throw of crank 312 may readily be adjusted by changing the angular position of stop 336 on shaft 338.

I have also provided a means for returning lever 314 and the associated assembly to its initial position after it has been engaged and actuated by cam roller 326. A crank 342 fixed on shaft 292 for rotation therewith is engaged by a spring 344 disposed on a stud or rod 346 fixed in shaft 160. It will readily be appreciated that the action of the spring 344 urges crank 342 and shaft 292 me clockwise direction as viewed in Figure 7 to pull rod 298 to the left as viewed in the figure and to rotate sleeve 306 in a directionto return lever 314 to the up position by the action of crank 312. The support bracket carries a pin 348 which is positioned to be engaged by crank 290 to limit the return movement of the crank.

A limitswitch 350 carried by brackets 352 is provided forinterruptingnthe circuit to motor when the elevator doors arrive at their fully closed position. Associated with the switch 350 is an actuating member 354 pivotally carried by rod 274. In order to actuate member 354 I provide a cam roller 356 pivotally carried by a pin 358 on a split collar 360 clamped on the head 232 of worm 230 by a bolt 362. As the doors arrive at their fully closed position and worm 230 and head 232 move to the left, roller 356 engages member 354 to actuate switch 350 to interrupt the motor drive circuit. When this occurs the doors are fully closed and the elevator is ready to move to the next floor. It will be understood that as the doors move to the fully closed position the safety switch 212 is closed so that the main motor drive circuit is in a condition to be energized.

In operation, when the elevator car arrives at a floor, the master control circuit, which is known to the art, operates to energize the door drive motor 150. The energization of motor 150 to open the doors drives shaft 152 and

pulleys

158, 164, 174, 176 and 184 in a counterclockwise direction as viewed in Figures 1 and 2 and in a clockwise direction as viewed in Figure 7. This action results in a travel of worm 230 to the right as viewed in Figure 5. As has been explained hereinabove, on the antecedent closing of the doors the pulley 184 has been left in the down position at which belt 172 engages the slow drive pulley 174 and worm 230 is in its extreme lefthand position as viewed in Figure 5. However, the direction of drive of belt 172 upon energization of drive motor 150 to open the elevator doors is such that the belt action pulls pulley 184 to the up position at which belt 172 engages the fast drive pulley 176. It is to be understood that the relative disposition of the parts of the assembly is such that arm 178 acts as a toggle arm. The inherent elasticity of belt 172 permits this action and tends to maintain the arm 178 in a beyond dead center position. As belt 172 urges the pulley 184 in one direction or the other, the momentum of the system carries the pulley past dead center with respect to shaft 180 so that it travels past dead center to the position opposite to that from which it has been moved. Accordingly, on opening of the doors the action of belt 172 urges pulley 184 from the down position as viewed in Figure 7 in which it has been left, to the up drive position at which the belt 172 engages the fast drive pulley 176. When this occurs, both

doors

32 and 34 move in an opening direction under the action of the fast drive. Door 32, however, moves faster than does door 34 by virtue of the mechanical advantage provided by the door pulley drive system. When the doors approach the fully open position, worm 239 has traveled a sufiicient distance to the right as viewed in Figure so that friction member 226 clamps the idler member 224 against friction disk 218. By virtue of this action, member 224 is engaged with shaft 74 and is rotated in a direction to push rod 262 to the left as viewed in Figure 7. This action lowers arm 178 to engage belt 172 with the slow drive pulley 174. The

doors

32 and 34 are driven at a slow speed until cam roller 284 engages member 278 to interrupt the door opening drive circuit of motor 150. It will be remembered that when pulley 184 is moved to the fast drive position during the initial portion of the opening movement of the doors, latch 192 is frictionally held out of engagement with pin 194 by pulley 174, on the hub of which latch 192 is mounted.

After a time delay relay (not shown) operates in a known manner, the direction of drive of motor 150 is reversed to close the doors. When motor 150 is so energized, shaft 152 and

pulleys

158, 164, 174, 176 and 184 rotate in a clockwise direction, as viewed in Figures 1 and 2, and in a counterclockwise direction, as viewed in Figure 7. It will be remembered that at the end of the opening movement of the doors, drive pulley 184 was left in the slow drive position at which belt 172 engaged pulley 174, member 224 was left clamped to shaft 74, and worm 230 was in its extreme right-hand position as viewed in Figure 5. As motor is energized to close the doors, member 224 is driven in a direction to move pulley 184 against the action of belt 172 to a position at which the belt 172 engages the fast drive pulley 176. Since the direction of rotation of pulley 174 is also reversed, latch 192 is moved to a position to engage pin 194 to hold pulley 184 in the fast drive position to which it has been moved. As Worm 230 moves to the left as viewed in Figure 5, as the doors close, cam roller 356 engages lever 314 to pivot sleeve 306 in a direction to move rod 298 to the right as viewed in Figure 7. This action rotates crank 290 in a direction to move latch 192 out of engagement with pin 194. The belt action then moves pulley 184 to the slow drive position at which belt 172 engages pulley 174. This occurs as the doors approach the fully closed position. A short time thereafter, cam roller 356 engages member 354 to actuate switch 350 to interrupt the door closing circuit of motor 150. This occurs when the doors arrive at their fully closed position. As the doors close, cam roller 206 closes safety switch 212 so that the elevator cab drive motor circuit may be energized to drive the cab to the next floor.

It will be seen that I have accomplished the objects of my invention. I have provided an improved elevator door operator having a slow speed terminal portion for both the opening and closing movements of the elevator doors. My operator delivers suflicient torque to operate both the cab doors and wall doors if necessary. Slippage in my system is distributed over almost the entire length of the drive belt. My operator is extremely flexible in that the same assembly may be used for a Wide range of door travels with only minor adjustments. My operator is not limited to sliding door type elevators but may be used on elevators having other kinds of doors. My operator is quieter than operators of the prior art.

' It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention. It is therefore to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, what I claim is:

1. A door operator including in combination a door, means mounting said door for movement between an open position and a closed position, first drive means for driving said door at a given speed, second drive means for driving said door at a speed which is less than said given speed, means for connecting said door alternately with said first drive means and said second drive means, and control means for actuating said connecting means to couple said connecting means with said first drive means during the initial portion of movement of said door toward each of said open position and said closed position and for actuating said connecting means to couple said connecting means with said second drive means during the terminal portion of movement of said door toward each of said open position and said closed position.

2. A door operator as in claim 1 including a common prime mover and means operated by said prime mover for driving said first and said second drive means.

3. A door operator as in claim 1 in which said connecting means includes a belt, means driven by said belt for moving said door, a pulley in engagement with said belt, and means mounting said pulley for movement alternately to engage said belt with the first drive means and to engage said belt with the second drive means.

4. A door operator including in combination a door, a belt, means driven by said belt for moving said door to an open position and to a closed position, first drive means for driving said belt at a given speed, second drive means for driving said belt at a speed less than said given speechbelt shifting means for connecting said belt I1 alternately with said first drive meansand with said second drive means, and control means for actuating said belt shifting means to engage said belt with said first drive means during the initial portion ofmovement of said door and for actuating said belt shifting means to engage said belt with said second drive means during the terminal portion of movement of-said door to either said open or closed positions.

5. A door operator as in claim 4'in which said first and second drive means move in one direction to move said door to the open position and in the opposite direction to move said door to said closed position, the direction of movement of said drive means when said dooris moving to said open position being such that said belt urges said belt shifting means to engage said belt with said first drive means, said control means including means for urging ,said belt shifting means to engage said belt with said second drive means as said door approaches the open position.

6. A door operator as in claim 4 in which said first and second drive means move in one direction to move said door to the open position and in the opposite direction to move said door to the closed position, the direction of movement of said drive means when said door is moving to said closed position being such that said belt urges the belt shifting means to engage said belt with said second drive means, said control means including means for moving said belt shifting means against the action of said belt to engage said belt with said first drive means at the beginning of the movement of said door to a closed position, means for retaining said belt shifting means against the action of said belt in a position where said belt engages said first drive means, and means for releasing said retaining means as said door approaches said closed position.

7. A door operator including in combination a door, means mounting said door for movement between an open position and a closed position, a drive belt, means operated by said drive belt for moving said door, a first drive pulley for driving said belt to move said door at a given speed, a second drive pulley for driving said belt to move said door at a speed which is less than said given speed, a belt shifting pulley engaged with said belt, means mounting said belt shifting pulley to engage said belt alternately with said first drive pulley and with said second drive pulley, and control means for moving said belt shifting pulley to a position where said belt engages said first drive means during the initial portion of the movement of said door and for moving said belt shifting pulley to a position where said belt engages said second drive pulley as said door approaches either of its open or closed positions.

8. A door operator as in claim 7 in which the direction of movement of said drive means when said door moves toward an open position is such that said belt shifting pulley is urged to a position where said belt engages said first drive pulley, said belt shifting pulley mounting means including a shaft, an arm carried by said shaft for rotation therewith, said control means including a clutch having a driving member and a driven member normally disengaged at the beginning of the movement of said door toward the open position, means responsive to the movement of said means connecting said belt to said door for engaging said driven and said driving members as said door approaches its open position to drive said driven member, a linkage connecting said driven member to said belt shifting pulley mounting shaft, the direction of drive of said driven member when engaged during the movement of said door to an open position being such as will move said belt shifting pulley against the action of said belt'to a position where said belt engages said second drive pulley. V g

9. A door operator as in claim 7 in which the direction of movement of said drive means when said door moves toward said closed position is such that said belt urges said belt shifting pulley to a position where said belt engages said second drive pulley, said belt shifting pulley mounting means including a shaft, an arm carried by said shaft for rotation therewith, said control means including a clutch having a driven member and a driving member carried by said means connecting said belt with said door, said driven and said driving members being normally engaged at the beginning of the movement of said door toward said closed position, means responsive to the movement of said means connecting said belt with said door for disengaging said clutch, a linkage connecting said driven member with said shaft, the direction of movement of said connectingmeans being such that said driven member urges said shaft ina direction to move said belt shifting pulley to a position where said belt engages said first drive pulley before the disengage-i ment of said clutch, means for retaining said belt shifting pulley support arm in a position where said belt engages said first drive pulley after said clutch is disengaged, and

means, actuated by said means responsive to the movement of said means connecting said belt with said door for disengaging said retaining means as said door apprime mover for said first drive pulley and said second drive pulley, first means responsive to the movement of said means connecting said belt with said door for deenergizing said prime moverwhen said door arrives at an open limit position and second means responsive to the movement of said means connecting said belt to said door for de-energizing said prime mover when said door arrives at a closed position.

ll. A door operator including in combination a door, means for mounting said ,door for movement between limit positions, a prime mover, first means driven by said prime moverat a given speed, second means driven by said prime mover at a speed which is less than said given speed, door drive means adapted to be coupled alternately with said first driven means or said second driven means, means connecting said door means to said door to move said door toward a limit position, means for coupling said door drive means alternately with said first driven means or said second driven means, and means for actuating said coupling means to couple said door drive means with said first driven means during the initial portion of the movement of said door toward each one of said limit positions and to couple said door drive means with said second driven means during the terminal portion of the movement of said door toward each of said limit positions.

12. A door operator including in combination a door,

, means for mounting said door for movement between open and closed positions, an endless belt, means driven by said endless belt for moving said door toward one of said positions, a first drive sheave for said endless belt, first drive means for driving said first sheave at a given peripheral speed, a second drive sheave for said endless belt, second drive means for driving said second sheave at a peripheral speed which is less than said given angular speed, a control pulley for said endless belt, means mounting said control pulley for movement alternately to a position where said endless belt engages said first drive sheave or to a position where said endless belt engages said second drive sheave and control means for actuating said mounting means to position said belt toengage said firstsheave during the initial portion of movement of said door toward one of said open or closed positions and to actuate said mounting means to position said belt to engage said second drive sheave during the terminal portion of movement of said door toward the other of said positions. V

13. A door operator as in claim 12 in which said mounting means-includes an arm, a shaft, means mounting said arm on said shaft for movement therewith, the direction of movement of said belt as said door moves to the open position beingsuch that said'control pulley is urged to sheave, said control means including a clutch responsive to said means driven by said endless belt for moving said shaft to move said pulley against the action of said belt to a position where the belt engages the second drive sheave.

14. A door operator as in claim 12 in which said mounting means includes an arm, a shaft, means mounting said arm on said shaft for rotation therewith, the direction of movement of said belt as said door moves toward the closed position being such that said control pulley is urged to a position to engage said second drive sheave, a clutch responsive to the movement of the means driven by the endless belt to urge said control pulley to position said belt to engage said first drive sheave at the start of movement of said door toward the closed position, latch means for retaining said arm in a position where said control pulley engages said belt with 1 1 said first drive sheave, and means responsive to said means driven by the prime mover for releasing said latch means at a predetermined point in the movement of said door toward the closed position.

References Cited in the file of this patent UNITED STATES PATENTS 676,833 Bitner June 18, 1901 2,432,293 Di Giovanni Dec. 9, 1947 2,458,402 Myers Ian. 4, 1949 2,526,503 Raque Oct. 17, 1950 2,572,196 Raque Oct. 23, 1951 2,598,709 Morris June 3, 1952 2,673,316 Doeg et al Mar. 23, 1954 2,700,542 Geyer Jan. 25, 1955 2,715,662 Andrews Aug. 16, 1955