US2826271A - Control mechanism for elevators - Google Patents

Description

Mar h 11, 1958 AQE. PRINCE CONTROL MECHANISM FOR ELEVATORS Filed Nov. 14, 1956 427/401? ENNIS PB/NCE INVENTOR W ATTORNEY United States Patent CONTROL MECHANISM FOR ELEVATORS Arthur Ennis Prince, Boonton Township, Morris County, N. L, assignor to Qtis Elevator Company, New York, N. Y., a corporation of New Jersey Application November 14, 1956, Serial No. 622,028

7 Claims. (Cl. 187-29) The invention relates to control mechanism for elevators and especially to control mechanism which is actuated in accordance with movement of the elevator car in the hoistway.

It is common practice in elevator installations to provide control mechanism which is driven by car movement and is positioned outside the hoistway, usually in the penthouse. Such mechanism is usually termed a selector or a floor controller. There are many functions of an elevator system which are controlled by such mechanism, among which are the picking up of calls that are registered, controlling the slowin down and stopping of the car, the lighting of hall lanterns, bringing the car to an exact landing level, control of the opening of the doors, and others. Selector machines have been provided in which the mechanism for controlling the leveling of the car at the floors at which stops are being made comprises a plurality of rotating cams, one for each floor, and switching mechanism which is actuated in accordance with car movement along a path parallel with the axis of rotation of the cams and which is brought into cooperative relationship with the cam for the floor at which the stop is being made to efiect the leveling operation. Elevator systems are growing more and more complex, and this has necessitated the adding of mechanisms to the selector, among which is mechanism to be actuated by the rotating cams for floors at which stops are being made. This is fast reaching a point of saturation and it has become a problem as to how to effect all the required control operations without the redesign of the selector.

It is an object of the invention to provide additional switching mechanism for actuation by the rotating cams.

In carrying out the invention according to the preferred arrangement, a member is provided which is actuated in accordance with the car movement along a path parallel to the axis of rotation of the cams and which carries a permanent magnet. Segments of magnetizable material are carried by the rotatable cams in position to come opposite the permanent magnet as the car reaches the respective floors for which the cams are provided to cause attraction of the magnet toward the cam. Circuit controlling mechanism is provided for actuation by the attraction of the magnet which causes the lever to pivot and may be utilized, for example, as a door zone switch, i. e., a switch for establishing a zone within which the doors may be opened as the car is being brought to a stop at a landing. Mechanism is also provided for preventing operation of the switch upon attraction of the permanent magnet by the magnetizable segments as the car passes floors at which stops are not being made.

Features and advantages will be seen from the above, taken in conjunction with the following description, claims and accompanying drawings.

In the drawings:

Figure l is a simplified schematic representation of an elevator installation including control mechanism actuated in accordance with car movement and embodying the invention;

Patented Mar. 11, 1958 Figure 2 is a plan view in fragmental detail of a permanent magnet switch embodied in the control mechanism of Figure 1 with the switch in position for cooperation with a magnetizable segment rotatable by car movement, but with the switch contacts held in unactuated condition;

Figure 3 is a view similar to Figure 2, but showing the switch contacts actuated; and

Figure 4 is a sectional view taken along the line 4-4 of Figure 2.

Referring to Figure 1, the hoisting rope 10 passes over the hoisting sheave 11 and connects the car 12 to the counterweight 13. The motor 14 drives the sheave 11, thus effecting the raising and lowering of the car and counterweight. Control mechanism drivenin accordance with car movement is illustrated schematically as a simpli fied form of selector machine driven preferably by means of a steel tape 15 attached to the car and counterweight and having teeth formed thereon for engaging teeth on the selector driving wheel 16.

The selector machine comprises a frame formed by a base plate 17 and a top plate 18 supported from the base plate by standards 20, one of which for convenience is illustrated as a guide bar 19. The driving wheel 16 is secured to the outer end of a shaft 21 rotatably supported on the base plate 17. A vertical screw 22 is driven by shaft 21 through the intermediary of bevel gears 23. The vertical screw 22 drives crosshead 24, which is guided in its vertical movement by guide bar 19.

The crosshead 24 carries brushes, indicated by a single brush 26, which cooperate with stationary-contacts to pick up calls, thereby selecting the floors at which stops are to be made. The stationary-contacts are indicated by a plurality of contacts 27, one for each floor, mounted on floor bars 28 attached to standards 20.

Switching mechanism operable in association with other parts of the control mechanism to bring the car to exact landing levels has been schematically arranged on the selector machine. Rotatable cam shaft 32 extends between base plate 17 and top plate 18. Leveling earns 33, one for each floor, are mounted in spaced relation along shaft 32 in accordance with the distances between their respective floors. A gear 34, driven by a gear 35 secured to vertical screw 22, effects rotative movement of the cam shaft 32. Two leveling switches, one for up leveling and one for down leveling are carried by the crosshead 24. Each switch comprises, three pivotally mounted contact levers 36, 37 and 38, each biased by a spring 39 towards the leveling cams 33. Lever 36 carries a contact 47 for engaging contact 48 carried by the crosshead. Lever 37 carries a contact 50 for engaging a contact 49 mounted on lever 36. Lever 38 carries a contact 51 for engaging a contact 52, also carried by lever 36. The pair of contacts 47 and 48 serve as interlock contacts; the pair of contacts 49 and 50 serve as up or down leveling direction contacts; and the pair of contacts 51 and 52 serve as fast speed leveling contacts.- Stops 40 are provided for levers 37 and 38; Lever 36 carries a follower 41 which cooperates with the leveling cams 33 to effect the actuation of the contacts. Leveling magnets 42 carried by the crosshead 24 are energized during movement of the car to attract armatures 43 thereby pivoting levers 36 to maintain followers 41 retracted. During slowdown, the leveling magnets 42 are de-energized to release the followers 41 for cooperation with the cam 33 for the floor at which the stop is being made to effect actuation of the contacts to bring the car to an exact landing level.

The above preferred arrangement of the switching mechanism is shown in the patent to E. L. Dunn et al., Number 2,074,578, granted March 23, 1937, to which ice reference may be made for details of construction. Improvements in control have been made which involve additional contacts actuated by the leveling cams with the resin: that it is very difficult to find room for additional contacts for actuation by the leveling cams. To provide ad oiial switching mechanism actua'table by the cams, ates-rang to the preferred arrangement, a plate 53 in the form of 'a segment of magnetizable material is formed or mounted on each leveling cam 33 at the periphery thereof. A permanent magnet switch 54 is carried by the crosshead 24 in position to pass close to magnetizable plates 53 as the crosshead moves along its path.

Details of permanent magnet switch 54 are shown in Figures 2, 3 and 4. Lever 55 is pivotally mounted on pin 56 extending between two sides of bracket '57, which projects from plate 58 secured to crosshead 24. A contact 59 is mounted on one 'arm of lever 55 to be moved thereby into position to engage a stationary contact 61. The stationary contact is formed by a pair of brackets 64 which are spaced "slightly apart and are secured to an insulatingblock 65 mounted on plate 58. The movable contact 59 is in the form of a leaf contact spring 60 having a pair of contact tips for engaging and bridging the contact brackets '64. A binding post 66 is provided on each bracket for connecting controls in the system. Lever '55 is biased by spring 63 extending from plate 58 to the other arm of lever 55, to maintain the movable contact 59 disengaged from the stationary contact 61. A stop 62 in the form of a projection from lever 55 limits the movement of lever 55 by its spring 63.

A permanent magnet 67 is mounted on lever 55 in position to be in close proximity to magnetizable plate 53 on the camperiphery when the car makes a stop at the floor for which the cam is provided. The permanent'magnet has north and south pole pieces 68 and 69 and is positioned in an elongated slot 70 formed in the lever. The permanent magnet is secured to the lever by 'a screw 71, a spring 72 being arranged between the permanent magnet and the lever. The airgap between the permanent magnet 67 and the plate 53 is adjustable by screw 71 against the pressure of spring 72. Lever 55 is adapted to be moved about its pivot against the force of its biasing spring to close contacts 59 and 61 by the magnetic attraction of the permanent magnet 67 to the magnetizable plate53. In the preferred arrangement the plate 53 is in the form of a segment of magnetizable material of constant radius and of predetermined arc length to establish a zone in which the permanent magnet 67 is attracted to the plate 53.

Extension -75 of one of the followers 41 engages an adjustable screw 76 on lever 55 when the lever is attracted 'to prevent movement c-f the lever about its pivot to actuate the contacts except when the followers are released forcooperation'with'a'leveling cam 33.

In operation, as the elevator car travels in the hoistway, steel tape rotates the driving wheel 16 which, through the intermediary of shaft 21, bevel gears 23 and vertical screw 22, drives the c'rosshead 24 in a vertical p'ath parallel to the longitudinal axis of the cam shaft 32. At the same time, the cam shaft 32 is rotated by gears 34 arid '35, thereby rotating leveling cams 33 about a common axis at a-speed proportional to car movement.

A call to stop the car at a floor is picked up by the engagementof brush 26 with a stationary contact 27 for afloor for which "the .callis registered as the crosshead is driven along its vertical path. This selects the floor at which the stop is to be made. As the car approaches the selected floor, the leveling magnets 42 are de-energized releasing followers 41 for cooperation with the leveling-cam 33 for that floor to bring the car to an exact landing level as disclosed in the aforementioned Dunn et a1. patent.

Permanent magnet 67 mounted-on lever 55 is attracted by magnetizable plate 53 along the periphery of each leveling cam 33 as the crosshead 24 moves in its vertical path. Extension 75 of the follower 41 prevents actuation of contact 59 to engage contact 61 as the permanent magnet 67 is attracted to the magnetizable plates 53, while the followers 41 are in retracted position. As the car approaches a selected floor, followers 41 are released, in turn releasing lever 55. Thus, as the car arrives at a certain distance from the floor, permanent magnet 67 is attracted to the magnetizable plate 53, thereby closing contacts 61 and 59. Permanent magnet 67 is prevented from engaging the magnetizable plate 53, since the movement of lever 55 is limited by contact brackets 64.

Incident to the car leaving the floor, the crosshead 24 moves along its path, the followers 41 are retracted and the lever 55 pivots under the force of its biasing spring 63. as the permanent magnet 67 and magnetizable plate 53 move apart, causing contacts 61 and 59 to open. As the followers 41 retract, extension 75 insures that the lever 55 pivots into position to disengage contact 59 from contact 61.

Although the control mechanism as described and illustrated can be utilized without leveling mechanism, but as independent control apparatus operable in accordance with car movement, the invention makes possible the in clusion of additional switching mechanism operable by the rotating cams, notwithstanding that all the available space in the leveling switching mechanism has already been utilized.

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

What is claimed is:

1. Control mechanism for an elevator system in which 'actuatingmechanism is provided for moving the elevator car, said control mechanism comprising a first member, at least a portion of which is of magnetizable material, means for rotating said first member at a speed proportional to the speed of said car, a crcsshead, means for moving said crosshead along a path parallel to the axis of rotation of said first member in accordance with car movement, a second member mounted on said crosshead for movement toward said first member, a permanent magnet mounted on said second member in a position of magnetic attractive relationship with said portion of magnetizable material on said first member as said .crosshead reaches a certain point in its movement, said second mem her being movable by said attraction as said point is reached, and switching means actuatable by said movement of said second member as said attraction takes place.

2. Control mechanism for an elevator system in which the elevator car serves a plurality of floors and in which means are provided for selecting the floors at which stops are to be made, said control mechanism comprising a plurality of spaced magnetizable plates, one for each of said floors, means for rotating said magnetizable plates about a common axis in accordance with car movement, means including a member which duplicates the movemerit of said car along an axis parallel to said common axis at a reduced speed, a permanent magnet mounted on said member and adapted to be attracted by each of said magnetizable plates as said permanent magnet comes into close proximity to that plate, and switching means actuatable by said attraction of said permanent magnet by a magnetizable plate for a floor selected as one at which a stop is to be made.

3. Control mechanism for an elevator system in which the elevator car serves a plurality of floors, said control mechanism comprising a plurality of magnetizable plates, one for each of said floors, means for rotating said plates about a common axis in accordance with car movement, a crosshead actuatable in accordance with movement of said car alonga'path parallel to said .common axis adjacent said plates, a lever pivotally mounted on said crosshead for movement with said crosshead as a unit, a contact on one end of said lever, a second contact carried by said crosshead for cooperation with said first named contact, and a permanent magnet mounted on said lever in position to come into close proximity with each of said magnetizable plates and adapted to be attracted thereby causing said lever to pivot and to actuate said contacts.

4. Control mechanism for an elevator system in which the elevator car serves a plurality of floors, said control mechanism comprising a plurality of magnetizable plates, one for each of said floors, means for rotating said plates about a common axis in accordance with the speed and direction of travel of said car, a crosshead actuatable in accordance with movement of said car along a path parallel to said common axis, a lever pivotally mounted on said crosshead for movement with said crosshead as a unit, a pair of cooperating contacts, one mounted on said crosshead, the other attached to said lever for movement therewith, a permanent magnet attached to said lever and adapted to pass close to each of said magnetizable plates as said crosshead is actuated along said parallel path, whereby said lever is moved about its pivot from an unattracted position toward said plates by the attraction of said permanent magnet to said plates to actuate said contacts, means operable to select a floor at which said car is to stop, and means for preventing said movement of said lever towards said plates at floors which have not been selected for stops to be made.

5. Control mechanism for an elevator system in which the elevator car serves a plurality of floors, said control mechanism having a crosshead actuatable in accordance with movement of said car, means actuated by said crosshead for selecting the floors at which stops are to be made, a plurality of leveling cams, one for each of said floors, rotatable at an angular velocity which is a function of car movement, and mechanism carried by said crosshead and rendered effective by selection of a floor at which a stop is to be made to cooperate with said leveling cam for that floor to control the operation of the car to bring it to a level with that floor, and being characterized in that there are provided a lever pivotally attached to said crosshead, a permanent magnet mounted on said pivoted lever, a plate of magnetizable material at the periphery of each of said leveling cams, switching mechanism actuated by pivotal movement of said lever as said permanent magnet passes said magentizable material and is attracted thereto, and restraining means controlled by said leveling mechanism for preventing operation of said switching mechanism at floors at which stops are not to be made.

6. Control mechanism for an elevator system in which the elevator car serves a plurality of floors, said control mechanism having a vertically movable crosshead which duplicates the vertical movement of said car at a speed proportional to the car speed, means actuated by said crosshead for selecting the floors at which stops are to be made, a plurality of leveling cams, one for each of said floors, rotatable in accordance with car movement, a pair of followers carried by said crosshead and adapted to be released for cooperation with the leveling cam for the floor selected for a stop to be made and a plurality of switches mounted on said crosshead and adapted to be mechanically actuated by the coaction of said leveling cam with said followers to level the car with such floor, and being characterized in that there are provided a lever pivotally mounted on said crosshead, a door zone switch having a contact on said lever in position to engage a contact on said crosshead, a spring biasing said lever to hold said contacts open, a permanent magnet mounted on said lever, a magnetizable segment of constant radius and predetermined arc length on each leveling cam at the periphery thereof in position to complete a magnetic circuit with said permanent magnet, whereby said permanent magnet is attracted to said magnetizable segment, thereby moving said lever on its pivot to close said door zone contacts whenever the vertical path of travel of said permanent magnet on the crosshead traverses the arcuate path of travel of said segment, and an extension of one of said followers to be engaged by said lever to cause said lever to pivot and close said contacts only when said followers are released for cooperation with the leveling cam at a selected floor stop.

7. Control mechanism for an elevator system in which the elevator car serves a plurality of floors, said control mechanism having a crosshead actuatable in accordance with movement of said car, means actuated by said crosshead for selecting the doors at which stops are to be made, a plurality of spaced floor cams, one for each of said floors, rotatable in accordance with car movement, and leveling mechanism including a pair of followers carred by said crosshead and rendered effective by selection of a floor at which a stop is to be made to cooperate with the leveling cam for that fioor to control the operation of the car to bring it to a level with that floor, and being characterized in that there are provided a lever pivotally mounted on said crosshead, a door zone switch having a contact on said lever adapted to engage a cor responding contact on said crosshead as said lever pivots, a spring biasing said lever to hold said contacts open, an extension arm of one of said followers to be engaged by said lever to prevent actuation of said contacts except when said leveling mechanism is rendered effective at a selected floor stop, a permanent magnet mounted on said lever, and a magnetizable plate on each cam along the periphery thereof and having an arc length predetermined to establish the door zone to pivot said lever by attraction of said permanent magnet, thereby closing said door zone contacts whenever said permanent magnet traverses the predetermined arc length of said magnetizable plate at a selected floor stop.

No references cited.

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