US3477177A - Hydraulically actuated door operator - Google Patents

Description

Nov, 11, 1969 B. W. TUCKER, JR

HYDRAULICALLY ACTUATED DOOR OPERATOR 2 Sheets-Sheet 2 Filed April 18, 19s? INVENTOR BENJAMIN -WH|TEHEAD TUCKER JR BY 245%. ATTORNEY United States Patent O 3,477,177 HYDRAULICALLY ACTUATED DOOR OPERATOR Benjamin Whitehead Tucker, Jr., South Orange, N.J., as-

siguor to Otis Elevator Company, New York, N.Y., a corporation of New Jersey Filed Apr. 18, 1967, Ser. No. 631,826

Int. Cl. Ef 15/00 U.S. Cl. 49138 12 Claims ABSTRACT OF THE DISCLOSURE An operating mechanism in which a reversible pump establishes a fluid pressure differential between two conduits of an actuator which responds by moving a member in a first or a second direction depending upon the sense of the pressure differential, which sense is determined by the direction in which the pump operates.

FIELD OF THE INVENTION This invention relates generally to mechanisms for moving a member in either of two directions and particularly to a hydraulic actuator suitable for opening and closing sliding doors such as those used in elevator systems.

BACKGROUND The quality of the service rendered by a modern high speed elevator installation depends, to a greater extent than is usually realized, on the efiicacy of the operation of the doors. Typically, both the elevator car door and the hoistway door are quite heavy and are operated by a single mechanism carried by the elevator car. The doors should open very rapidly and can do so safely as there is no chance of striking a passenger while opening. However, during closing, safety demands that the doors be under control so that they can be stopped quickly, or even reversed, to avoid injuring a passenger in their path. The doors should operate quietly and reliably, and must not slam as either the fully opened or the fully closed position is reached. Such operation places severe demands upon the door operating mechanism.

In the past, elevator doors have been operated by a number of devices, one popular arrangement comprising a compressed air motor mounted on top of the car and mechanically connected to the car door. Various valving arrangements, actuated manually or automatically, have been used to control the direction and speed of the door. Dash pots or other hydraulic cushioning mechanisms have been provided to ease the stops at the fully opened and fully closed positions. While such mechanisms often operated satisfactorily, they required a supply of compressed air which was furnished either by a long flexible hose depending from the car or a tank mounted on the car. For this and other reasons, compressed air motors have largely been superseded by electric motors mechanically connected to the door through a speed reducing and motion converting mechanism. The energization of the motor is controlled continuously or in many steps according to whether the door is being opened or closed and according to whether the door is near the beginning or end of its excursion. Such variation in energization requires complex electric control equipment but even with such equipment it has usually been necessary to provide one or more hydraulic cushioning devices to ease the door to a stop as it reaches its fully opened and fully closed positions.

It is a general object of the present invention to provide an improved door operating mechanism.

Another object is to provide a reversible actuator in which the actuating and cushioning functions are performed by the same device.

Another object is to provide an operating mechanism 3,477,177 Patented Nov. 11, 1969 ICC SUMMARY Briefly stated, a preferred embodiment of a door operating mechanism incorporating the invention comprises an electric motor directly connected to a reversible pump. The pump includes first and second channels which serve asiinlet and outlet respectively, or vice versa, according to the direction in which the pump is driven. These two channels are connected to first and second conduits of a reversible hydraulic actuator of the cylinder and piston variety. These two conduits communicate with the cylinder on opposite sides of the piston so that the direction of piston travel is determined by the sense of the fluid pressure differential existing between the two conduits. The piston is connected to the door through suitable linkage. A plurality of adjustable valves between the conduits and the cylinder enable the motion of the door to be controlled separately for each direction of travel while the electric motor, after initial adjustment, need be controlled only to select Forward, Off, or Reverse operation.

DESCRIPTION OF DRAWING For a clearer understanding of the invention, reference may be made to the following detailed description and the accompanying drawing, in which:

FIGURE 1 is a view, partly schematic, of a mechanism according to the invention operatively connected to an elevator car door;

FIGURE 2 is a pictorial view of the door operating mechanism;

FIGURE 3 is a cross section view taken as indicated by the line 33 of FIGURE 2;

FIGURE 4 is a cross section view taken as indicated by the line 44 of FIGURE 2;

FIGURE 5 is a cross section view taken as indicated by the line 55 of FIGURE 2;

FIGURE 6 is a fragmentary elevation view of that side of the apparatus which is hidden from view in FIGURE 2; and

FIGURE 7 is a fragmentary cross section view taken as indicated by the line 77 of FIGURE 3.

DESCRIPTION OF PREFERRED EMBODIMENT Referring first to FIGURE 1, there is shown an elevator car 11 on the top of which is mounted a door operator 12 in accordance with the present invention. The operator 12 is connected to an arm 13 which in turn is pivotally connected to a link 14 which is similarly pivotally connected to an elevator door 15. The operator 12 rotates the arm 13 in one direction or the other to open or close the door 15.

Referring now especially to FIGURES 2 and 3, the operator 12 includes a body 21 which houses a pump and a piston-cylinder actuator and which supports, on one side, an electric motor 22. The body 21 is formed with a cylindrical bore or cylinder 23 at one end and with a similar, coaxial cylinder 24 at the other end. A piston assembly designated generally by the reference character 25 is located within the cylinders 23 and 24 and preferably comprises a pair of piston heads 26 and 27 positioned within the cylinders 23 and 24 respectively and rigidly joined together by a rod 28 so that the assembly may move back and forth as a unit, from right to left and back again as viewed in FIGURE 3.

The body 21 is also formed with first and second supply chambers 31 and 32 adjacent to the cylinders 23 and 24 respectively. Similarly, first and second exhaust chambers 33 and 34 are also formed in body 21 adjacent to the cylinders 23 and 24 respectively. The chamber 34 is not illustrated but has been assigned a reference character to facilitate subsequent description. It is similar to the cham- 3 her 33. All of these chambers may be in the form of cylindrical bores. A cap 35 is bolted to one end of the body 21 to close the cylinder 23 and the chambers 31 and 33 while a cap 36 is bolted to the other end to close the cylinder 24 and the chambers 32 and 34.

The body 21 is formed with horizontally extending bosses 41 and 42 at opposite ends, as shown. The boss 41 has four adjustable throttling valves 43, 44, 45 and 46 threadedly mounted thereon while the boss 42 has four similar valves 47, 48, 49 and 50 similarly mounted on it. The valves 43 and 44 extend into openings formed in body 21 between the chamber 33 and the cylinder 23 and are adjustable to control the flow of fluid from the cylinder 23 to the chamber 33. Similarly, the valves 45 and 46 extend into openings between the chamber 31 and the cylinder 23 and control the flow of fluid from chamber 31 to the cylinder 23. In a like manner the valves 47 and 48 control the flow of fluid from the cylinder 24 to the chamber 34 and the valves 49 and 50 control the flow of fluid from the chamber 32 to the cylinder 24. An additional opening 53 is formed between the exhaust chamber 33 and the cylinder 23 and is left clear with no throttling valve. Similarly, an additional opening 54 (not illustrated) is formed between the exhaust chamber 34 and the cylinder 24 and is also unobstructed.

The body 21 is also formed with two channels 56 and 57 either of which may be the inlet while the other is the outlet for a fluid pump 58. The pump 58 includes a rotor element 59 keyed to the shaft 61 of the electric motor 22. The pump is reversible, that is, it draws fluid from the channel 56 and urges it toward the channel 57, or vice versa, depending upon the direction of rotation of the rotor element 59, thereby generating a pressure differential between these channels the sense of which likewise depends upon the direction in which the element 59 is rotated. However, the details of the pump are not a part of the present invention. One kind of pump which has been found to be satisfactory is designated a Gerotor type 6063 and is obtainable from its manufacturer, the W. H. Nichols Company, Waltham, Mass.

The channels 56 and 57 are connected to conduits 63 and 64 respectively formed in the body 21. The conduit 63 (FIGURE 4) communicates with the supply chamber 31 through a ball check valve 65, oriented so as to permit fluid to flow from the conduit 63 to the supply chamber 31 while preventing the flow of fluid from the chamber 31 to the conduit 63. The conduit 64 (FIGURE 3) communicates with the supply chamber 32 through a ball check valve 66 similarly oriented so as to permit fluid to flow from the channel 57 through the conduit 64 and the valve 66 to the supply chamber 32 while preventing flow in the opposite direction.

The body 21 is also formed with a generally vertical passageway 67 which interconnects the conduit 63 with a space 68 formed in the body 21 adjacent to the exhaust chamber 33. The chamber 33 communicates with the space 68 through a ball check valve 69 which is positioned so as to permit the flow of fluid from the chamber 33 through the valve 69, the space 68 and the passageway 67 to the conduit 63 while preventing the flow of fluid in the opposite direction.

As might be inferred from the description up to this point, the entire operator 12 including the body 21 is symmetrical about the plane represented by the line A-B of FIGURE 3. Accordingly, the body 21 is also formed with another generally vertical passageway 71 (not shown) similar to the passageway 67, which interconnects the conduit 64 with a space 72 (not shown but similar to the space 68) adjacent to the exhaust chamber 34 (not shown). A ball check valve 73 (not shown, but similar to the valve 69) is mounted between the last mentioned space and the exhaust chamber 34 so as to prevent the flow of fluid from the conduit 64 to the chamber 34 while permitting flow in the opposite direction. As previously mentioned in connection with the unillustrated chamber 34, the assignment of reference characters to the above mentioned unillustrated passageway, space and valve facilitates reference thereto in the subsequent explanation.

As best shown in FIGURES 4, 5 and 6, the rod 28 which joins the piston heads 26 and 27 is formed with rack teeth 76 which mesh with the teeth of a gear sector 77 fastened to a shaft 78 which in turn is fastened to the arm 13. It is apparent that linear motion of the rod 28 imparts rotary motion to the gear sector 77, shaft 78 and arm 13.

Let us assume that the parts are in the positions shown in the drawing with the door closed and that all of the cylinders, chambers, conduits, passageways, spaces, channels, etc. are filled with a suitable fluid such as oil. In order to open the door, the electric motor 22 is energized so as to rotate the rotor element 59 in that direction which establishes a pressure differential between the channels 56 and 57 with such a sense that fluid tends to be drawn from the channel 56 and urged into the channel 57. As best shown in FIGURE 3, fluid flows from the channel 57, through the conduit 64 and the check valve 66 into the supply chamber 32. Fluid cannot flow at this time through the throttling valve 49 because the piston head 27 blocks its opening but fluid can and does flow through the valve 50, at a rate determined by its adjustment, into the end of the cylinder 24. As pressure increases, the piston as sembly is moved to the left, as viewed in FIGURE 3, and in so moving acts through the rack teeth 76 (FIGURE 4), the gear sector 77, the shaft 78, the arm 13 and the link 14 to open the door. As the piston head 26 (FIGURE 3) moves, it forces fluid from the cylinder 23 through the unrestricted opening 53 into the exhaust chamber 33 from whence it flows through the check valve 69, the space 68, and the passageway 67 to the conduit 63 and the channel 56 to the pump 58.

During the first stage of the door opening operation, the speed is determined primarily by the adjustment of the valve 50. When the piston assembly has moved to the left sufficiently, the piston head 27 uncovers the opening containing the valve 49 which valve can be adjusted to provide an increase in fluid flow and a consequent increase in door speed. As the door nears its fully opened position, the piston head 26 first covers the unrestricted opening 53 thereby limiting the flow of fluid to that through the valves 43 and 44. Each, of course, may be adjusted. Finally, the piston head 26 covers the opening containing the valve 44 limiting flow to that through the valve 43. This valve remains uncovered since it is positioned beyond the limit of travel of the piston head 26.

During the door opening operation, fluid flows from the cylinder 23 to the channel 56 as above described not only because it is so urged by the piston head 26 but also because the pump 58 at this time draws fluid from the channel 56. The successive covering of the opening 53 and the opening containing the valve 44 restricts the supply of fluid with a resulting tendency toward cavitation. Such a tendency is relieved, as shown in FIGURES 3 and 7, by a ball check valve 81 formed in the shell or case 82 of the pump 58 at a point where it separates the channel 56 from the surrounding space enclosed by the body 21, more specifically, the portion 83 of the body 21. This valve is oriented to allow fluid to flow as necessary from the aforesaid space to the channel 56 but not in the reverse direction. A similar valve 84 (FIGURE 3) relieves the tendency toward cavitation during door closing by allowing fluid to be drawn into the channel 57.

In order to close the door, it is only necessary to energize the electric motor 22 so as to turn the rotating element 59 in the opposite direction so as to establish a pressure differential between the channels 56 and 57 of such a sense that fluid is drawn from the channel 57 and urged into the channel 56. It is deemed unnecessary to describe the operation in detail because it is analogous to the door opening operation already described.

It is to be noted that the check valves 65, 66, 69 and 73 are oriented, or poled, so as to allow fluid to flow into the cylinders 23 and 24 only through the supply chambers 31 and 32, and not through the exhaust chambers 33 and 34. Similarly, these valves allow fluid to flow out of the cylinders 23 and 24 only to the exhaust chambers 33 and 34 and not to the supply chambers 31 and 32. This arrangement insures that the throttling valves 49, 50, 43 and 44 are effective during and only during door opening while the throttling valves 45, 46, 47 and 48 are effective during and only during door closing. In each case the supply of fluid to the cylinders is controlled by two throttling valves and the exhaust is controlled by two other throttling valves. This arrangement provides great versatility in the control of the door motion from the beginning to the end of the excursion.

From the foregoing it is apparent that a door operating mechanism in accordance with the present invention provides excellent control of the door movement. The characteristics of the opening and closing movements are selected entirely independently of each other. Each operation may be quick, yet is adequately cushioned at each limit of travel. It has been found to be unneccessary to vary the motor energization during operation. A simple three position control, forward, off and reverse, is ade quate. No auxiliary braking, either dynamic or friction, is required. No auxiliary dash pots are needed.

Although a preferred embodiment of the invention has been described in considerable detail for illustrative purposes, many modifications can be made within the spirit of the invention. It is therefore desired that the protection afforded by Letters Patent be limited only by the true scope of the appended claims.

What is claimed is:

1. An operating mechanism for moving an elevator door, comprising, reversible fluid pump means, first and second cylinder bodies axially spaced along a longitudinal axis, first and second pistons respectively disposed in said first and second cylinder bodies forming first and second variable volume enclosed cylinder spaces, said first and second cylinder spaces being respectively connected to said pump means, said first and second pistons respectively having first and second axially outer end faces, said first and second end faces respectively having areas which are substantially equal, a piston rod extending between said first and second pistons, said piston rod having opposite end portions respectively connected to said first and second pistons, mechanical means operatively interconnecting said piston rod and said elevator door, said pump means including first and second channels in which selected fluid pressures are generated for opening and closing said elevator door, said first and second cylinder bodies including first and second conduits which are connected to said first and second channels respectively, said first and second cylinder bodies respectively forming first and second passage means which respectively extend between said first and second conduits and said first and second cylinder spaces, said first and second passage means including a plurality of openings facing said first and second cylinder spaces, and said first and second pistons being adapted to coact with said openings to selectively vary the sizes of said openings for controlling the speed of travel of said elevator door.

2. An operating mechanism for moving an elevator door between open and closed positions, comprising, a reversible fluid pump, first and second cylinder bodies axially spaced along a longitudinal axis, first and second pistons respectively disposed in said first and second cylinder bodies forming first and second variable volume enclosed cylinder spaces, said first and second cylinder spaces being respectively connected to said pump, said first and second pistons respectively having first and second axially outer end faces, said first and second end faces respectively having areas which are substantially equal, a piston rod extending between said first and second pistons, said piston rod having opposite end portions respectively connected to said first and second pistons, mechanical means operatively interconnecting said piston rod and said elevator door, first and second supply chambers respectively formed in said first and second cylinder bodies, first and second exhaust chambers respectively formed in said first and second cylinder bodies, said first cylinder body being formed with a first plurality of openings extending between each of said first supply and exhaust chambers and said first cylinder space, said second cylinder body being formed with a second plurality of openings extending between each of said second supply and exhaust chambers and said second cylinder space, first and second conduits respectively connected between said first supply and exhaust chambers and said pump and between said second supply and exhaust chambers and said pump, and a plurality of check valves interposed between said conduits and said supply and exhaust chambers for preventing the flow of fluid from said conduits to said exhaust chambers and from said supply chambers to said conduits.

3. An operating mechanism for moving a member, comprising, a reversible fluid pump, first and second cylinder bodies axially spaced along a longitudinal axis, first and second pistons respectively disposed in said first and second cylinder bodies forming first and second variable volume enclosed cylinder spaces, said first and second cylinder spaces being respectively connected to said pump, said first and second pistons respectively having first and second axially outer end faces, said first and second end faces respectively having areas which are substantially equal, a piston rod extending between said first and second pistons, said piston rod having opposite end portions respectively connected to said first and second pistons, and mechanical means operatively interconnecting said piston rod and said member, in which said pump includes a rotatable element and first and second channels between which a fluid pressure differential is generated in a sense determined by the direction in which said element is rotated and in which said first and second cylinder bodies respectively include first and second conduits which are connected to said first and second channels respectively and in which said first and second cylinder bodies respectively form first and second passage means which respectively extend between said first and second conduits and said first and second cylinder spaces for moving said member in a first or second direction as determined by the sense of the pres sure differential existing between said conduits and in which said first and second passage means include a plurality of openings facing said first and second cylinder spaces and in which said first and second pistons are adapted to coact with said openings to selectively vary the sizes of said openings.

4. An operating mechanism according to claim 3 further comprising an elevator door operatively connected to said member for movement thereby between open and closed positions and in which said first and second cylinder bodies have a plurality of adjustable throttling valves positioned in said openings.

5. An operating mechanism according to claim 3 further comprising means for rotating said element of said pump selectively in either direction and in which said first and second passage means respectively include first and second supply chambers and first and second exhaust chambers and in which said plurality of openings extend between each of said first supply and exhaust chambers and said first cylinder space and extend between each of said second supply and exhaust chambers and said second cylinder space and in which said first and second passage means have a plurality of check valves interposed between said first and second conduits and said first and second supply and exhaust chambers for preventing the flow of fluid from said conduits to said exhaust chambers and from said supply chambers to said conduits.

6. An operating mechanism according to claim 5 in which said means for rotating said element is a reversible electric motor and in which said mechanical means operatively interconnecting said piston rod and said door operating member includes a shaft having gear means mounted on one end thereof and connected to said piston rod and having linkage means mounted on the opposite end thereof and connected to said door operating member.

7. A reversible actuator for moving a member selectively in either one of two opposite directions, comprising, a body, cylinder means formed in said body, piston means operatively connected to said member and positioned within said cylinder means for movement in opposite directions in response to the existence of a fluid pressure differential on opposite sides thereof, first and second supply chambers formed in said body, one adjacent to each end of said cylinder means, first and second exhaust chambers formed in said body, one adjacent to each end of said cylinder means, said body being formed with a plurality of openings extending between each of said chambers and said cylinder means, a plurality of adjustable throttling valves positioned in said openings for controlling the flow of fluid therethrough, first and second conduits for conveying fluid to and from said first supply and exhaust chambers and to and from said second supply and exhaust chambers respectively, and a plurality of check valves interposed between said conduits and said chambers for preventing the flow of fluid from said conduits to said exhaust chambers and from said supply chambers to said conduits, whereby a fluid pressure differential existing between said conduits is impressed, through said chambers, said valves and said cylinder means, on opposite sides of said piston means.

8. Apparatus according to claim 7 in which said cylinde-r means includes first and second coaxial cylinders axially displaced from each other and in which said piston means includes first and second piston heads disposed in said first and second cylinders respectively and interconnected to move in unison.

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9. Apparatus according to claim 8 in which said first supply and first exhaust chambers are formed adjacent to said first cylinder and said second supply and second exhaust chambers are formed adjacent to said second cylinder and in which said openings extend from each of said chambers to the adjacent cylinder.

10. Apparatus according to claim 8 further comprising a reversible pump including a rotatable element and first and second channels between which a fluid pressure differential is generated in a sense determined by the direction in which said element is rotated, said first and second channels being connected to said first and second conduits respectively for transmitting said fluid pressure diflerential thereto.

11. Apparatus according to claim 8 in which said piston heads are interconnected by a rigid rod formed with rack teeth which engage a rotatable gear operatively connected to said member.

12. Apparatus according to claim 11 in which an elevator door is operatively connected to said member for movement thereby between open and closed positions.

References Cited UNITED STATES PATENTS 1,047,600 12/ 1912 Williams. 2,192,175 3/1940 Ballard. 2,286,661 6/ 1942 Warner 92-136 XR 1,937,244 11/1933 Pelton 91-24 XR 1,957,697 5/1934 Conway 91-24 1,970,286 8/1934 Dunn. 2,212,998 8/1940 Crane. 2,246,461 6/ 1941 Cannon 91-27 2,388,755 11/1945 McLeod. 2,927,429 3/ 1960 Carlson.

EDGAR W. GEOGHEGAN, Primary Examiner US. Cl. X.R.

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