US2495902A - Dumb-waiter door and cam operator - Google Patents

Description

3" 195 3 1 L. Mc U DUMBWAITER DOOR AND CAM OPERATOR gwwm 3 Sheets-Sheet 1 Filed June 26, 1948 IIIIIIIIIIIIIIIIIIII.

INVENTOR. ARTHUR L. MCI \EA UL,

ATTO F/VFXS Jan. 31, 1950 MGKEAGUE 2,495,902

DUMBWAITER DOOR AND CAM OPERATOR Filed June 26, 1948 v 3 Sheets-Sheet 2 INVENTOR. ARTHUR LMCKEAGUL A T f/VEYS Jan, 31, 39% A. L. M KEAGUE DUMBWAITER DOOR AND CAM OPERATOR 5'SheetsSheet 5 Filed June 26, 1948 x?) J l INVENTOR. ARTHUR LMCKEA GU11 BY L Patented Jan. 31, 1950 DUMB-WAITER DOOR AND CAM OPERATOR Arthur L. McKeague, Staten Island, N. Y., as-

signor to Syncro Machine Company, Perth Amboy, N, J a corporation of New Jersey Application June 26, 1948, Serial No. 35,505

13 Claims.

The present invention relates to means for operating the doors of a dumbwaiter, and particularly to a means for operating: the doors which utilizes a torque motor and which causes opening movement of the doors without shock.

More particularly still, the invention relates to such dumbwaiter door operating units which may also operate the retiring cam in timed relationship with the door opening and closing movements, this retiring cam controlling the unlatching of the shaft doors in the usual manner.

More particularly still, the invention relates to a mechanism to effect the combined functions of operating a dumbwaiter door and a retiring cam which mechanism is effective to initiate door and retiring cam operation simultaneously and to complete the door opening movement after the unlatching of the shaft doors by the retiring cam.

Additionally, the present invention provides an overrunning clutch and a spring to assure that the doors in their movement will not rebound and cause strain in the unit.

It is an object of my invention to provide a dumbwaiter door operatorv having means for automatically opening and closing the doors and being provided with means for assuring that the door movements will be without impact, said operator including a torque motor.

It is another object of the invention to provide such a unit which likewise controls the operation of the usual retiring cam.

It is another object of the invention to provide a door operating unit in which the movement of the retiring cam is of a standard amount and the movement of the door operating mechanism is adjustable to adapt the unit to dumbwaiters having different heights and resulting diiferently dimensioned doors.

It is a further object of the invention to provide a door and retiring cam operating unit in assuring that the shaft doorways are unlatched;

at the time when the car doors reach their fully open position. In closing the withdrawal of the retiring cam is initiated when the car doors are nearly closed and thus the shaft doors are latched slightly, before the car doors reach their fully,

closed position.

It is a still further objectof the invention to provide such a unit which is readily mounted up on the dumbwaiter and readily connected for operation ofthe doors and the retiring cam.

- dumbwaiter frame.

Other objects and features of the invention will become apparent when the following description is considered in connection with the annexed drawings, in which:

Figure 1 is a front elevation of a dumbwaiter having the door and retiring cam operator of my invention mounted thereon and connected for use;

Figure 2 is an enlarged fragmentary sectional view of the door and cam operator of Figure 1, the section being taken on the plane of the line 22 of that figure;

Figure 3 is a developed cross-sectional view of the device of Figure 1;

Figure 4 is a fragmentary view of the unit of my invention, with the housing partly broken away, showing particularly the construction of the rebound eliminating means; and

Figure 5 is a fragmentary view showing the mode of attaching the door operating chain to a bracket which is in turn fixed to the door.

The dumbwaiter is generally indicated at In in Figure 1. On top of the dumbwaiter structure there is mounted the door and cam operator of the present invention, being generally designated H. The dumbwaiter doors are of the center operating type, vertically movable, and are here shown at 12 and i3. The upper door I2 is connected bymeans of a bracket [4 to the center portion of a turnbuckle I5, which is in turn connected at its ends to the ends of a chain Hi. The chain I 6 is in effect an endless chain, due to the connection of its ends by means of the turnbuckle l5, and is driven by the sprocket wheel I! in a manner to be hereinafter described.

This chain also passes over the idler sprocket l8 which is suitably mounted in an upper frame member 2!] of the dumbwaiter structure. Sheaves may be substituted for the idler sprocket l8 as well as for the similar idler sprockets 23 and 25 hereinafter described.

The retiring cam 2| is suspended from a chain 22, which chain, in the usual manner, passes over a sprocket Wheel 23 rotatably mounted on the The chain 22 cooperates with the operating mechanism in a manner which will be hereinafter described. As has been indicated above, the retiring cam operates to unlatch the shaft or hatchway door at which the dumbwaiter has been stopped. The details of this operation need not be here described since they are Well known in the art.

The lower door l3-is connected to the upper door [2 and operates therewith, although in,the opposite direction. This operation is brought designated 28. The shaft 26 is driven by means of a torque motor 30, i. e. a motor which can be stalled across the line for varying amounts Such motors are known in the art and.

of time. are rated in foot pounds of torque and in the percentage of time that they canbe stalled'with' power connected. Thus a duty motor can be stalled with power on for six minutes out of every hour. would preferably be one of 50% rated duty. The torque motor 36 drives shaft 26 through the medium of a pair of sprocket wheels, one being mounted on the motor shaft and one on shaft 26, the latter being designated 3I, and a chain 32 passing over these sprocket wheels.

Fixed to the shaft 26 for rotation therewith is a. pinion 33 which cooperates with a gear 34 rotatably mounted on shaft 35, the latter shaft being likewise supported in bearings in the front and rear plates 21. Gear 34 is free to'rotate upon shaft 35 and has connected with it the outer member 36 of an overrunning clutch, the inner member 31 of which is keyed to shaft 35, this overrunning clutch being of a common form and consisting of a toothed drum having rollers in the tooth spaces, as is well known in the art. Likewise keyed to shaft 35 is a pinion 38 which meshes with a gear 40 keyed to shaft 4I, this shaft being likewise supported in bearings in the front and rear plates 21.

Fixed to shaft M for rotation therewith is a sprocket wheel I1, previously described (see Figures 1 and 2) which operates the doors I2 and I3. In a particular embodiment the sprocket dimensions are such that the doors travel ten inches for each rotation of sprocket wheel I1 and the motor speed and gear ratios are such that the doors move at a rate of approximately eight inches per second.

In order to provide that the hatch doors be unlocked during the final opening movement of the dumbwaiter doors I2 and I3, a time delay mechanism in the form of an escapement washer is provided.

This escapement washer comprises a disc or plate 42 rotatably mounted on shaft 4| and carrying a pin 43 extending laterally thereof adjacent its periphery.

Adjacent washer 42 and to its right, as seen in Figure 3, is a sleeve 44 which carries sheaves 45 and 46. Sleeve 44 is mounted in a bearing in plate 21 and shaft M is in turn rotatably supported in the sleeve. Mounted radially in the hub 41 of gear 40 is a pin 48 which pin in its rotation will strike pin 43. Extending radially from sleeve 44 is a pin 56 which lies in the path of rotation of the pin 43.

Thus as shaft 4I turns washer 42 will remain fixed for a predetermined fraction of a turn after which it will be forced to rotate with the shaft. Similarly after washer 42 starts to rotate a predetermined fraction of a turn will be traversed before pin 43 strikes pin 56;thereafter the sleeve 44 will rotate with the shaft.

The motor used in this instance 4 Sheave 46 operates the retiring cam the connection therebetween being by means of chain 22 which is fastened to the sheave by means of pin 53 in a manner clearly indicated in Figure 3.

In like manner, a chain 52 is fastened to sheave 45 by a pin 5|. The opposite end of chain 52 is suitably fastened to a rod 54 guided in a U shaped bracket 55 and upper portion of housing 28. Rod 54 is provided with a washer 56 which limits its upward movement and a compression spring51 extends between bracket 55 and nut 58 on the threaded end of the rod. Thus during movement of sleeve 44, the spring 51 is compressedservingas a clamping device to check the last few inches of door travel and to eliminate strain and rebound in the unit. This spring also serves to initiate the opening movement of the doors when power is removed from the motor 30.

The details of the connection of chain I6 to the door are shown in Figure 5. Reference to this figure will show that the angle bracket I4 is connected to a turnbuckle I5 at a predetermined position thereon by means of the nuts 60 and washers 6I. Each end of chain I6 is provided with an offset collar 62 into which one end of the turnbuckle extends being held in adjusted position by means of nuts 63.

As will be apparent from the foregoing description, circuits of'known type are provided so that when the dumbwaiter arrives at a predetermined fioor the power to the torque motor is shut off. Thereupon the doors starting opening due to the energy stored in spring 51 (Figure 1) acting'through pin 52 andcausing sheave 45 (Figure 4) to rotate in a direction to open the doors. The rotation of sheave 45 (Figure 3) causes sleeve44 and sheave 46 to also revolve. The rotation of sheave 46 causes chain 22 (Figure 1) to unwind and the retiring cam to thus be advanced due to the action of a spring incorporated'in-the retiring cam as well as by gravity in the usual manner.

As sheave45 rotates the-pin 56 bears against pin 43'inmember 42 which in turn bears against pin 48 in thehub 41 of gear 40. Since gear 46 is keyed to the shaft II, the sprocket wheel I1 is also caused to rotate and this motion is transmitted through chain I6: to the upper door causing it to move in an opening direction. The completionv of opening movement of the doors is brought about due tothezfact that the lower door is heavier than the upper one. Thus the shaft. 4|: continues to revolve after sleeve 44 has been stopped resultingin separation of the pins 48 and 43 from driving connection with the pin 50. The door movement continues until the upper door is stopped by the rubber bumpers 65 on the door guides 64..

A11 rotation of shaft 4I (Figure 3) and of gear 40 is, of course, transmitted through pinion 38 to the overrunning clutchv 3631 and through it to gear 34, pinion 33 and sprocket 3I to the torque motor 30 (Figure 1) causing the motor to rotate in a reverse direction. When the upper door is stopped as described. all rotating parts back to the clutch member 31 also stop. However, the use of the overrunning clutch permits the motor armature and sprocket 3 I, pinion 33, gear 34 and member 36 of the overrunning clutch to continue to revolve and thus prevents sudden dissipation of the kinetic energy stored in the rotor of motor 30. In this way the overrunning clutch prevents the energy of the motor armatur or rotor from being trans mitted to the doors and thus prevents excessive impact of the upper door against stops 65 (Figure 1).

Due to the use of a torque motor operated as described, the dumbwaiter doors are opened and the hatohway doors unlatched upon a power.

failure and thus access to the shaft and dumbwaiter permitted.

When the dumbwaiter is called to another floor, the torque motor is energized. After considerable movement of the motor and the doors the rotation of gear 40 brings the pin 48 into contact with pin 43 of member 42 and thereafter contirmcd rotation brings pin 43 into contact with pin 59 whereupon rotation of sleeve 44 commences. Thus the retiring cam is retracted during the last portion of the closing movement of the doors and likewise during this last portion of closing movement the spring 5'! is compressed.

While I have described a preferred embodiment of my invention, it will be understood that modifications thereof may be utilized within the scope and spirit of my invention. Consequently, I wish to be limited not by the foregoing description but, on the contrary, solely by the claims granted to me.

What is claimed is:

1.. An operator for the car doors and retiring cam of a dumbwaiter comprising, in combination, a torque motor, a gear reduction unit driven by said torque motor, an output shaft driven by said reduction unit, said output shaft being operatively connected to the car doors, an escapement washer driven by said output shaft, and means driven by said escapement washer for operating said retiring cam, whereby said retiring cam advances during the initial movement of said car doors to open position and retreats during the final movement of the doors to closed position.

2. An operator for the car doors and retiring cam of a dumbwaiter as claimed in claim 1, characterized in that the position of said escapement washer is adjustable to determine the proportion of the total movement of said output shaft which shall be effective on said retiring cam.

3. An operator for the car doors and retiring cam of a dumbwaiter as claimed in claim 1, characterized in that said gear reduction unit comprises an over-running clutch thereby permitting said torque motor to run free when the doors reach their final position preventing damage to said u.

4. An operator for the car doors and retiring cam of a dumbwaiter comprising, in combination, a torque motor, a gear reduction unit driven by said torque motor, an output shaft driven by said reduction unit, said output shaft being operatively connected to the car doors, an escapement washer driven by said output shaft, means driven by said escapement washer for operating said retiring cam, whereby said retiring cam operates during the final movement of said car doors to closed position, a second escapement washer driven by said output shaft, spring cushioning means, and means driven by said second escapement washer for tensioning said spring cushioning means to thereby damp the final closing movement of the car doors and said torque motor.

5. An operator for the car doors and retiring cam of a dumbwaiter according to claim 4, charaoterized in that said gear reduction unit oomprises an over-running clutch, whereby said torque motor may run free of said output shaft during the final door opening and retiring cam movement.

6. An operator for the car doors and retiring cam of a dumbwaiter according to claim i, char- 5 acterized in that said torque motor, gear reduction unit and spring cushioning means are mounted on the dumbwaiter. 7. An operator for the car doors and retiring cam of a dumbwaiter according to claim 4, characterized in that said second escapement washer drives a sheave freely rotatable upon said output shaft, said sheave being connected to said retiring cam by-a chain, and said second escapement washer also drivesa second sheave adjustably 15 freely connected to said first sheave, said second 7 sheave being connected to said spring cushioning means by a chain.

8. An operator for the car doors of a dumbwaiter comprising, in combination, a torque motor, a shaft driven by said motor and driving the car doors, an escapement washer driven by said shaft in the direction of door closing movement, spring cushioning means, and means driven by said escapement washer for tensioning said spring means to damp the final closing movement of the car doors and the torque motor, said tensioning of said spring means also providing an initial impulse toward open position of the car doors when said torque motor is deenergized.

9. An operator for the car doors of a dumbwaiter comprising, in combination, a torque mtor, a gear reduction unit driven by said torque motor, an output shaft, driven by said reduction unit, said output shaft being operatively con nected to the car doors, an escapement washer driven by said shaft in the direction of door closing movement, spring cushioning means and means driven by said escapement washer for tensioning said spring means to damp the final closing movement of the car doors and the torque motor, said tensioning of said spring means also providing an initial impulse toward open position of the car doors when said torque motor is deenergized.

10. An operator for the unbalanced vertically movable car doors of a dumbwaiter comprising, in combination, a torque motor, a shaft driven by said motor and driving the car doors, an escapement washer driven by said shaft in the direction 50 of door closing movement, spring cushioning means, means driven by said escapement washer for tensioning said spring means to damp the final closing movement of th car doors and the torque motor, said tensioning of said spring 55 means also providing an initial impulse toward open position of the car doors when said torque motor is deenergized, the unbalanced door weight driving the doors to open position, and an overrunning clutch operatively connected between 50 said shaft and said torque motor, said clutch serving to disconnect said motor from said shaft upon the car doors reaching their fully open position, whereby the inertia of said motor is not applied to said doors and impact of the doors is eliminated.

11. An operator for the car doors of a dumbwaiter comprising in combination, a torque motor,

a shaft driven by said motor and driving the car doors, an escapement washer driven by said shaft 70 in the direction of door closing movement, a

sheave driven by said escapement washer, a chain fixed to said sheave and adapted to be wound thereon, a piston connected to said sheave and a spring coiled about said piston, said spring being 75 tensioned by movement of said piston during final closing movement of the car doors to damp the final closing movement of the car doors and the torque motor, said tensioningof said spring means also providing an initial impulse toward open position of the cardoors when said torque motor is deenergized.

12. An operator for the car doors of, a dumbwaiter comprising, in combination, a torque motor, a gear reduction unit driven by said torque motor, an output shaft driven by said reduction unit said output shaft being operatively connected to the car doors, an escapement washer driven by said shaft in the direction of door closing movement, a sheave driven by said escapement washer, a chain fixed to, said sheave and adapted to be wound thereon, a piston connected to said sheave and a spring coiledv about said piston, said spring being tensionedby movement of said piston during final closing movement of the car doors to damp the final closing movement of the car doors and the torque motor, said tensioning of said spring means also providing an initial impulse toward open position of the car doors when said torque motor is deenergized.

13. An operator for the unbalanced vertically movable car doors of a dumbwaiter comprising, in combination, a torque motor, a shaft driven by said motor and driving the car doors,,an escapement washer driven by said shaft in the direction of door closing movement, a sheave driven by said escapement washer, a chain fixed to said sheave and adapted to be wound thereon, a pistonconnected' to said sheave and a spring coiled about said piston, said Spring being tensioned by movement of said piston during final closing movement of the car doors to damp the final closing movementof the car doors and the torque motor, said tensioning of said spring means also providing an initial impulse toward open position of the car doors when said torque motor is deenergized, the unbalanced door weight driving the doors to open position, and an overrunning clutch operatively connected between said shaft and said torque motor, said clutch serving to disconnect said motor from said shaft upon the car doors reaching their fully open position, whereby the inertia of said motor'is not applied to said doors and-impact of. the doors is eliminated.

ARTHUR L. McKEAGUE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,906,677 Waldman May 2, 1933 2,175,906 McCormick Oct. 10, 1939 2,458,402 Myers Jan. 4, 1949

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