US3500963A - Control system for elevators and the like - Google Patents

Description

March 17, 1970 A. J. BEUTLER 3,500,953

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United States Patent O 3,500,963 CONTROL SYSTEM FOR ELEVATORS AND THE LIKE Arthur J. Beutler, Greendale, Wis., assignor to Stair `Chair Corporation, Cleveland, Ohio, a corporation of Wisf cousin Filed June 11, 1968, Ser. No. 736,112 Int. Cl. B66b 9/ 06, 1]/04; H02k 17/02 U.S. Cl. 187-12 8 Claims ABSTRACT F THE DISCLOSURE A control system for an elevator mountable on a pair of rails and having a chair or platform on which a passenger may sit or stand. The control system permits both the passenger on the elevator and an operator located at the head or foot of the stairs to regular the up and down `movement of the chair. The control system may also be utilized to limit the travel of the chair along the rails.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to control systems for elevators.

Description of the prior art The control system of the present invention iinds particular utility in elevators commonly employed on stairways to aid the physically handicapped, semi-invalid, and elderly in ascending and descending stairs. Such elevators are mounted on one or more rails atlixed to the stairs or adjacent walls. The elevator includes a chair or platform, on which the passenger may sit or stand, having the appropriate supporting frame with rollers or sliding members engaging the rails.

The elevator is moved upwardly along the rails by a drive means which may, for example, wind a cable connected to the elevator onto a drum by means of an electric motor. The elevator is moved downwardly along the rails by unwinding the cable oif the drum, allowing the elevator to descend by gravity.

Such elevators must include a control system by which the passenger may control the up and down movement of the elevator. It is also desirable to provide a control means at both the head and foot of the stairs to permit one not on the elevator to control its movement. For eX- ample, a control means may be provided at the head of the stairs to move the elevator upwardly along the rails to the head of the stairs so that the operator may board the elevator. Similar means may be provided at the bottom of the stairs to return the elevator to the foot of the stairs.

It may also be desirable to incorporate, in the control system, travel limiting means for automatically de-energizing the drive means when the elevator reaches the top or the bottom ends of the rails so as to prevent excessive stress or slackness in the cable.

In the past, numerous problems have arisen in the provision of a satisfactory control system for such elevators. In the main, these problems have arisen because of the need to provide electrical power from a power source, such as a wall socket, to the movable element of the elevator, such as the chair, so as to permit the passenger to control the operation of the elevator. In some cases, spring tensioned reels have been employed to pay out and retract a power cord providing electrical power to the chair, as the chair descends and ascends the rails. See, for example, U.S. Patents 2,619,195; 2,619,196; and

3,500,963 Patented Mar. 17, 1970 ICC 2,719,607, all to Scott. In other cases, extendable coil cords have been employed for the same purpose.

However, such power cords inevitably become kinked, tending to cause the conductors in the cords to break and to cause a failure of the control system. The constant ilexing of the conductors, as the cords are wound on the reel or extended therefrom, hastens the breakage of the conductors even in the absence of kinking. There is also the ever present danger that the cord will be caught under the chair or between the chair and the rails and ripped apart by the motion of the chair. The reliability and trouble free operation of the elevator, which form important considerations in a device designed for use by the handicapped, semi-invalided, and elderly, is substantially lessened by the possibilities of conductor breakage.

To avoid the use of a power cord to the elevator, conductors affixed to the rails and connected to a power supply have been utilized. Collectors are mounted on the elevator to receive the power from the conductors. See, for example, U.S. Patents 2,824,623 and 2,923,379 to Nord and Stelzer, respectively. However, to overcome the shock hazard inherent in unshielded conductors containing volts or more, guards are required around the conductors. The guarded conductors tend to accumulate the dust present on the stairway rapidly because of their semi-enclosed construction. This has interferred with the operation of the collectors. Large particles of dirt and other objetos tend to jam the conductor-collector structure, causing loss of control over the operation of the elevator, and rendering the operation of such control systems no more reliable than those employing power cords.

SUMMARY OF THE INVENTION It is, therefore, the object of the present invention to provide an improved control system for elevators, which control system eliminates both the need for power cords and the need for shielded conductors, thereby providing a safe, reliable control system. The control system provides regulation over the up and down movement of the elevator by a passenger thereon, as well as by an operator not on the elevator. The control may also provide regulation over the limits of travel of the elevator.

The control system is energized from a power supply having a pair of terminals providing alternating current power. The control system includes means connecting one terminal of the power supply to one of the rails on which the elevator is mounted and means providing a pair of current paths, from the other terminal of the power supply. Preferably, the aforesaid means comprises a stepdown transformer which reduces the voltage of the power supply to a nonhazardous level. One of the aforesaid pair of current paths includes a iirst poled diode connected in series with a iirst control element which places the drive means for the elevator in a condition to move the elevator upward along the rails when energized. The other of the pair of paths includes a second poled diode, oppositely poled from the first diode, and a second control element placing the drive means in Aa second condition to move the chair downwardly along the rails when energized. Both of the current paths are connected to the other of the rails.

A collector means is mounted on the elevator to engage each of the rails. The collector means is interconnected by a series connected first switch and a diode poled to complement the first poled diode. The collector means is also interconnected by a series connected second 'switch and a diode poled to complement the second poled diode.

By closing the iirst switch, the passenger completes a circuit which energizes the lirst control element from the power supply to cause the drive means to move the elevator upwardly along the rails. By closing the second switch, the passenger completes a circuit which energizes the second control element from the power supply to cause the drive means to move the elevator downwardly along the rails.

The rails may also be interconnected adjacent thelr upper ends by a series connected switch and a diode poled to complement the irst poled diode. This switch, when closed, also completes a circuit which energizes the rst control element and permits an operator not on the elevator to move the elevator to the head of the stairs. The rails may be further interconnected adjacent their lower ends by a switch operable to energize the second control element and a diode poled to complement the second poled diode. This switch permits an operator at the foot of the stairs to move the elevator downwardly along the rails.

Travel limit control may be obtained by providing insulated rail portions extending beyond the ends of the rails and two pairs of collectors in the collector means on the elevator. The pairs of collectors are spaced apart in the direction of travel of the elevator so that one pair of collectors engages the insulated portion extending beyond the upper ends of the rails when the elevator is in the upper travel limit position and the other pair of collectors engages the insulated portion extending beyond the lower ends of the rails when the elevator is in the lower travel limit position. One pair of collectors is interconnected by the series connected rst switch and diode. The other pair of collectors is interconnected by the second series connected switch and diode.

When the elevator is in the upper travel limit position, the one pair of collectors engages an insulated portion and prevents further movement of the elevator in the upper direction, and when the elevator is in the lower travel limit position, the other pair of collectors engages an insulated portion and prevents further movement of the elevator in the downward direction.

BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is a perspective view of an elevator with which the control system of the present invention may be employed:

FIGURE A2 is a schematic diagram of the control system of the present invention; and

FIGURE 3 is a partial schematic diagram of a modifcation of the control system of FIGURE 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGURE 1 shows a stairway elevator 8 with which the control system of the present invention may be employed. Elevator 8 includes chair 10 affixed to frame 12 for movement along spaced, parallel rails 14 and 16 up and down stairs 18.

Rails 14 and 16 may be mounted on stairs 18 by anchoring straps 20. The length of rails 14 and 16 may be such that the ends of the rails are coterminous with the desired limits of travel of chair 10 up and down stairs 18. The rails are formed of electrically conductive material as, for example, a metallic material such as steel or c'opper, and are electrically isolated or insulated from each other. For purposes of structural strength and rigidity, rails 14 and 16 may be braced at either end by lateral lbraces 22 and 24 extending between the rails and having short rails portions 22a and 24a mating with rails 14 and 16. To maintain the electrical isolation between rails 14 and 16, insulating washers or plugs 26, formed of plastic, rubber, or other nonconductive material, may be inserted between the rails 14 and 16 and rail portions 22a and 24a if braces 22 and 24 are formed of electrically conductive material as shown in FIGURE l. In the alternative, braces 22 and 24 may be formed of electrically nonconductive material, as shown in FIGURE 2 by the numerals 221 and 241. The position of insulating Washers 26, or the length of rail portions 22a and 24a,

' 4 determines the limits of travel of elevator 8 along rails 14 and 16, as hereinafter described.

Frame 12 includes a pair of vertically disposed rightangle frame members 28 and 30 having horizontal portions extending inwardly towards stairs 18 and vertical portions extending downwardly towards stairs 18. The seat of chair 10 is mounted on the horizontal portions of frame members 28 and 30 and the ends thereo-f fastened to transverse member 31 which spans rails 14 and 16. The lower ends of the vertical portions of frame members 28 and 30 are fastened to transverse member 32 which likewise spans rails 14 and 16. The transverse members may be joined by longitudinal member 34 containing a footrest 36 for the passenger in chair 10. The ends of the I transverse members contain roller supports 38, each of Elevator 8 is moved along rails 14 and 16 lby cables 48 and 50 fastened to transverse member 31 of frame 12. The cables are reeved through pulleys 52 and 54 and wound on drum 56 mounted at the head of the stairs. Drum 56 may be rotated through an appropriate gear box by electric motor 58 energized with the alternating current power usually present in a house or dwelling from wall socket 59 or other power source. Motor 58 may be a split phase motor, the direction of rotation of which is reversed by reversing the energization of the starting winding. The elevator is moved upwardly along rails 14 and 16 by winding cables 48 and 50 onto drum 56. The elevator is moved downwardly along the rails by rotating motor 58 in the opposite direction so as to unwind cables 48 and 50 off drum 56 and permit elevator 8 to descend along rails 14 and 16 by gravity.

Control system 60 for elevator 8 may be energized from the same power source 59 as motor 58. In the preferred embodiment of the control system, a stepdown transformer 62 having a primary winding 64 connected to power source 59 is included in control system 60 to reduce the voltage of the power source to a lower voltage to lessen or eliminate the hazard of electrical shock in control system 60.

One end or terminal of secondary winding 66 of transformer 62 is connected to rail 14 by means of conductor 67. The other end or terminal of secondary winding 66 is connected to a pair of conductors 68 and 69 forming a pair of current paths. Interposed in conductor 68 is a poled diode 70 and a relay coil 72. Diode 70 may be poled so as to conduct current during the positive half cycles of the alternating current voltage in transformer secondary winding 66. Relay coil 72 operates relay contacts 721 which, when closed, connect the main and starting windings (not shown) of motor 58 to the alternating current power source so as to cause the motor to wind cables 48 and 50 onto drum 56 and raise elevator 8 upwardly along the rails. Relay coil 72 may hereinafter be termed the up relay coil. Interposed in conductor 69 is a poled diode 74, the polarity of which is opposite to the polarity of diode 70, and a relay coil 76.

Diode 74 is poled to conduct current during the negative half cycles of the alternating current voltage in transformer secondary winding 66. The contacts 76-1 of relay coil 76, when closed, connect the main and starting windf ings of motor 58 to the alternating current power source so as to cause motor 58 to unwind cables 48 and S0 off drum 56 and lower elevator 8 downwardly along the rails. Relay coil 76 may hereinafter be termed the down relay coil. To prevent simultaneous operation of both relay coils 72 and 76, and possible faulty operation of control 60, normally closed interlocking relay contacts 72-2, operated by relay coil 72, are connected in series with diode 74 and relay coil 76 and normally closed interlocking relay contacts 76-2 are connected in series with diode 70 and relay coil 72. The ends of both conductors 68 and 69 are connected to rail 16 to complete the current paths.

Stepdown transformer 62 may reduce the power supply voltage so that approximately 6 to 30 volts appear in transformer secondary winding 66.

An electrical collector means is mounted on. elevator 8 to contact rails 14 and 16 and receive electrical current therefrom as the elevator moves along the rails.4 The collector means may be mounted on roller supports 38. In lthe preferred embodiment of control system .60, the collector means includes 2 pairs of collectors spaced apart in the direction of travel of elevator 8. One pair of collectors 78 may be mounted on the roller supports 38 connected to transverse member 31 so as to precede the movement of elevator 8 in the upward direction. Collectors 78 may hereinafter be termed the up collectors. The other pair of collectors 80 is mounted on roller supports 38 connected to transverse member 32 so as to precede the movement of the elevator in the downward direction. Collectors 80 may hereinafter be ltermed down collectors. 4

Up collectors 78 are interconnected by a series connected normally open switch 81 and diode 82. Diode 82 is poled to complement diode 70; that is, diode 82 conducts current during the positive half cycle of the alternating current voltagel in secondary winding 66. Down collectors 80 are interconnected by a series connected normally open switch 84 and diode 86. Diode 86 is poled to complement diode 74; that is, diode 86 conducts current during the negative half cycles of the alternating current voltage existing in secondary winding 66. Switches 81 and 84 are mounted on control panel 46.

To move elevator 8 in the upward direction along rails 14 and 16, switch-81 is closed. The current generated by the positive half cycles of the alternating current voltage in secondary winding 66 of transformer 62 ows from the secondary winding 66 through conductor 68, diode 70, relay coil 72, rail 16, one of collectors 78, closed switch 81, diode 82, the other of colletcors 78, rail 14, and conductor 67, back to secondary winding 66. The current through relay coil 72 closes relay contacts 72-1 to connect motor 58 to the alternating current power source. Motor 58 winds cables 48 and 50 onto drum 56 to move elevator 8 up rails 14 and 16. Y

Relay coil 76 is not energized because of open switch 84 and because diodes 74 and 86 block the above described current ow in conductorv 69 containing relay coil 76. y

To move elevator 8 in the downward direction along rails 14 and 16, switch 84 is closed. The current generated during the negative half cycles of the alternating current voltage in secondary winding 66 of transformer 62 iiows from the secondary winding through conductor 67, rail 14, one of collectors 80, diode 86, switch 84, the other of collectors 80, rail 16, conductor 69, relay coil 76, diode 74, and back to secondary winding 66. The current through relay coil 76 closes relay contacts 76-1 to connect motor 58 to the alternating current power source in a manner to cause motor 58 to unwind cables 48 and 50 off of drum 56 to permit elevator 8 to descend along rails 14 and 16. Up relay coil 72 is not energized because of open switch 81 and because diodes 70 and 82 block current flow in conductor 68 and relay coil 72.

From the foregoing, it will be appreciated that the control system of the present invention forms a simple, convenient, and highly efficient means of permitting the passenger in an elevator to control the operation of the elevator without requiring retractable or coiled power cords or shielded rail conductors and the like.

Situations may arise in which the empty elevator 8 is at the bottom of the stairs and the passenger is at the top of the stairs, or vice versa. To move elevator 8 upwardly along rails 14 and 16, under such conditions, rails 14 and 16 are interconnected by a series connected diode 92 and normally open switch 94 at the upper end of the rails. The

switch and diode may be mounted in any convenient means such as wall mounted receptacle 96. Diode 92 is poled in the same current direction as diode 82 so as to complement diode 70 in conductor 68.

To move elevator 8 upwardly along the rails, switch 94 is closed. This allows the current generated during the positive halfb cycles of the alternating current voltage in transformer secondary winding 66 to flow through conductor 68, diode 70, relay coil 72, rail 16, diode 92, switch 94, rail 14 and conductor 67 back to secondary winding 66. The current through relay coil 72 energizes the relay coil and operates relay contacts 72-1 to cause motor 58 to wind cables 48 and 50 onto drum 56 to raise the elevator.

In a similar manner, a series connected diode 96 and switch 98, interconnecting rails 14 and 16, and located at the bottom of the stairs or elsewhere, may be used to move elevator 8 downwardly along the rails. Diode 96 is poled to complement diode 74.

The travel limiting features of control system 60 are provided in the following manner. Assume switch 84 is closed and elevator 8 is descending along rails 14 and 16, as described above. As the elevator descends, it will reach a position in which collectors will encounter washers 26 and the electrically insulated or nonenergized rail portions 22a of brace 22. This encounter will break the circuit between collectors 80, even though switch 84 is closed, and will de-energize relay coil 76, opening relay contacts 76-1 and preventing further movement of elevator 8 in the downward direction.

As collectors 78 remain in contact with rails 14 and 16, the elevator may be moved in the upward direction by closing switch 81.

The same travel limiting action occurs at the upper end of rails 14 and 16. That is, when elevator 8 is in the upper limit of travel, collectors 78 encounter washers 26 and nonenergized rail portions 24a and prevent further movement of elevator 8 in the upward direction even though switch 81 is closed. The elevator may, however, be moved in the downward direction by closing switch 84.

As shown in FIGURE 3, one collector of each pair may be interconnected by conductor 88. A switch is connected to conductor 88 and to switches 81 and 84. Switches 81 and 84 may be combined into a single poledouble throw switch for selecting the desired direction of travel while switch 90 may be a push-to-operate switch to energize motor 58 and move elevator 8 in the desired direction of travel as selected by switch 81 or 84.

It will be appreciated that if the travel limiting features of control 60 are not required, one or the other of the pairs of collectors may be eliminated and a single pair of collectors interconnected by switch 81 and diode 82 and switch 84 and diode 86 utilized.

It is appreciated that variations and modications may be made to the present invention and that the control system may be utilized on apparatus other than the elevator disclosed herein. For these reasons, the expositions herein have been by way of exemplary description only and it is desired to cover all such variations, modifications and utilizations -as come within the true scope and spirit of the invention.

What is claimed is:

1. A control system for an elevator or the like supported by a pair of electrically conductive, spaced rails, said rails being insulated from each other, said elevator being movable along said rails by a drive means coupled thereto, said drive means operable to a iirst condition for moving said vehicle in one direction along the rails and operable to a second condition for moving said vehicle in the other direction along the rails, said control system being energizable from a power supply having -a pair of terminals providing alternating current power and comprising:

means connecting one terminal of said power supply to one of said rails, means providing a pair of current paths from the other terminal of said power supply, one of said current paths having a first poled diode connected in series with a first control element for placing said drive means in said first condition when energized, the other of said current paths having a second poled diode, oppositely poled from said rst diode, and a second control element for placing said drive means in said second condition when energized, both of said current paths being connected to the other of said rails; and

collector means mounted on said vehicle and engaging each of Said rails, said collector means being interconnected by a series connected first switch operable to energize said first control element and a diode poled to complement said first poled diode, said collector means also being interconnected by -a series connected second switch operable to energize said second control element and a diode poled to complement said second poled diode.

2. The control system of claim 1 wherein said rails have insulated portions extending beyond each end thereof, said elevator being movable by said drive means from a first position wherein said elevator is located at one end of said rails to a second position wherein said elevator is located at the other end of said rails and wherein the collector means of said control system in* cludes two pairs of collectors mounted on said elevator, one collector of each pair engaging each of said rails, said pairs of collectors being spaced apart in the direction of travel of said elevator so that at least one collector of one pair of collectors engages the insulated portion extending beyond the said one end of said rails when said elevator is in said first position and at least one collector of the other pair of collectors engages the insulated portion extending beyond said other end of said rails when said elevator is in said second position, said one pair of collector means being interconnected by said series connected rst switch and diode, said other pair of collectors being interconnected by said second series connected switch and diode, whereby when said elevator is in said rst position said one pair of collectors engages an insulated portion and prevents further movement of said elevator in the direction of said first position and when said elevator is in said second position said other pair of collectors engages an insulated portion and prevents further movement of said elevator in the direction of said second position.

3. The control system of claim 1 wherein said control system includes a stepdown transformer having the primary winding connected to the terminals of said power supply and a secondary winding, one end of said secondary winding being connected to one of said rails, the other end of said secondary winding providing said pair of current paths.

4. The control system of claim 2 wherein said control system includes a stepdown transformer having a primary winding connected to the terminals of said power supply and a secondary winding, one end of said secondary winding being connected to one of said rails, the other end of said secondary windings providing said pair of current paths.

5. The control system of claim 1 wherein said rails are interconnected by a series connected switch, operable to energize one of said first and second control elements, and a diode poled to complement said poled diode connected in series with said one of said first and second control elements.

6. The control system of claim 5 wherein said rails are further interconnected by a series connected switch, operable to energize the other of said first and second control elements, and a diode poled to complement said poled diode connected in series with the said other of said first and second control elements.

7. The control system of claim 2 wherein one collector of each pair is interconnected and wherein a third switch is interposed in series with both of said first and second switches and said interconnected collectors so as to energize the one or the other of said control elements as selected by the operation of one of said first or second switches.

8. The control system of claim 1 wherein said first and second control elements comprise relays having the coils thereof interposed in said pair of paths and the contacts thereof operatively associated with said drive means.

References Cited UNITED STATES PATENTS 2,824,623 2/1958 Nord 187--12 2,012,634 12/1961 Stelzer 187-12 HARVEY C. HORNSBY, Primary Examiner U.S. C1. X.R.

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