US987384A - Rope-drive elevator. - Google Patents

Description

D. L. LINDQUIST & A. SUNDH.

ROPE DRIVE ELEVATOR. APPLIOATION FILED 1150.15, 1908.

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D. L LINDQUIST & A. SUNDH.

ROPE DRIVE ELEVATOR. APPLICATION FILED DBO.15, 19 00.

Patented Mar. 21, 1911.

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DAVID L. LINDQUIST AND AUGUST SUNDH, OF YONKERS, NEW YORK, ASSIGNGES T0 OTIS ELEVATOR COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ROPE-DRIVE ELEVATOR.

To all whom it may concern:

Be it known that we, DAVID L. LINDQUIST, a subject of the King of Sweden, and AU- eUsr S'UNDH, a citizen of the United States, residing in Yonkers, in the county of West chester and State of New York, have invented a new and useful Improvement in Rope- Drive Elevators, of which the following is a specification.

Our invention relates to improvements in traction or direct drive elevator apparatus, and has for one of its objects the provision of simple and elfective means for producing the necessary tension upon the traction driving cables.

A further object is the provision of means for distributing the tension on the driving cables u-pon opposite sides of the traction driving sheave.

Other objects will appear hereinafter, the novel combinations of elements being pointed out in the annexed claims.

In the accompanying drawings, Figure 1 represents in side elevation a rope drive or traction elevator apparatus embodying our invention in its preferred form. Fig. 2 is a similar view showing a modification. Fig. 3 is a detail view showing the plurality of cables.

Similar characters of reference denote similar parts in the figures.

Referring to F ig. 1, M designates a motor of any desired character, herein shown as an electric motor, upon whose shaft 11 is securely fastened a grooved tract-ion sheave 10 adapted to receive a plurality of endless driving cables 16. These cables lead over a grooved sheave 19 located at the upper part of the hatchway at a point above the upper limit of car travel. The sheave 19 is adapted to rotate about its pivot 20 which is carried upon one end of a pivoted beam 21. This beam 21 is pivoted at 22 upon brackets 28 which are adjustably secured to fixed beams 24. The other end of the beam 21 carries a pivot 27 upon which a sheave 26 is adapted to rotate. Holes 22 are provided in the beam 20, so that by changing the position of the brackets 23 along the beams 24, the pivot 22 of the beam 21 may be varied as desired without altering the position of the cable sheaves 19 and 26. At a suitable location 17 upon the cables 16, the cables 17 are connected, which cables lead up over a sheave 14 supported upon suitable brackets Specification of Letters Patent.

Application filed December 15, 1908.

Patented Mar. 21, 1911. Serial No. 467,707.

secured to the stationary beams 15. These cables 17 lead over the sheave 26 and are connected to a suspended counterbalance weight W. The elevator car C is suspencled by cables 18 which pass up over guide sheaves 28, 28, and are connected to the driving cables 16 at a suitable location 18 thereon. The guide sheaves 28 are supported by brackets 29, 29 which are secured to the stationary beams 24. If desired, an additional counterweight W may be provided. This weight is connected to the top of the car C by means of cables 25 which lead over stationary sheaves 32 supported by the beams 24.

The operation of the motor M may be efl ected in any desired manner, such as by means of a controller A whose operation is effected from the car by means of a hand switch 30. Electrical connections are made between the car switch 30 and the controller A, also between the motor M and the controller. The motor field terminals are designated by 12, while the armature terminals are shown at 18. The controller a is con nected by means of the conductors and to any suitable source of electrical supply. By means of the switch 30 carried by the car, the motor may be started, stopped or reversed at will, the movements of the elevator car and counterbalance weight being in accordance therewith.

Referring to the modification as shown in Fig. 2, it will be seen that the car suspension cables 18 pass up over a sheave 28 which is mounted upon the pivoted beam 21 by means of the brackets 31. The pivotal point of the sheave 28 is arranged vertically above the pivotal point 22 of the beam 21. The cables 18 are connected as before to the driving cables 16 at the point 18.

In traction or direct drive elevator apparatus it is desirable and essential that there be sufiicient tension upon the driving cables to prevent their slipping; also that this tension be equally distributed, or substantially so, upon the opposite sides of the traction driving sheave. If the tension is too great, the cables, bearings and other parts are subjected to a destructive strain and rapidly wear out. If the tension is too little, the cables will slip, especially upon starting and stopping, which not only wears out the cables rapidly, but also seriously interferes loaded car will be 3,7 50 pounds.

7 with a vertical line.

with the proper operation of the entire apparatus, rendering it almost impossible to make a proper landing with the elevator car. Furthermore, it is found in actual practice that the tension upon the driving cables, due to the combined weights of the car and counterbalance acting directly, is not always sutlicientto prevent slipping. Various ways and means have been devised to overcome this feature, such as using additional weights, but such means are open to the objection that they entail unnecessarv expense and complication, and at the same time tend to lower the etliciency of the apparatus as a whole. Our invention overcomes these and other unclxsirable features.

Referring once more to Fig. 1, it is seen that the weight of the car and whatever load may be therein act-ing directly through the cables 18, produces a corresponding tension upon the driving cables 16 at the right-hand side of the grooved traction or driving sheave 10. In a similar manner the counterweight 7 acting directly through the cables 17 produces corresponding tension upon the driving cables at the left-hand side of the sheave 10. The counterweight W not only produces a tension on the driving cables, due to its own weight acting directly, but produces an additional tension by means of the pivoted beam 21 associated therewith. The counterweight tends to depress the sheave 26, thereby rocking the beam 21 about its pivot point 22 and causing the sheave 19 to move upwardly, thereby tightening the driving cables about the traction sheave 10.

In order to determine the traction of the driving cables with the arrangement of parts as illustrated in Fig. 1, we will assume that the elevator car when empty weighs 1,250 pounds, and has a maximum load capacity of 2,500 pounds, therefore the weight of the Carrying out the usual policy in elevator practice of employing a counterweight equal in weight to that of the car and average load, the counterweight will weigh 2,500 pounds. The tension throughout the cable 17 is therefore 2,500 pounds. The pressure of this cable on the sheave 26 and the lever 21 may be considered as consisting of two components, namely, a vertical pressure of 2,500 pounds due to the lead extending downward from the sheave 26, and a pressure of 2,500 pounds in the direction of the lead extending from the sheave 26 to the sheave 14:. Let it be assumed that this last lead makes an angle of The tension on this lead may then be resolved into two components, namely, a horizontal and a vertical component. The vertical component is equal to the cosine of the angle of 60 multiplied by 2,500 pounds, or 1,250 pounds. This 1,250 pounds represents the extent to which the said vertical pressure of 2,500 pounds is counterbalanced. The downward pull upon the sheave 26 due to the counterweight is therefore equal to the difference between 2,500 pounds and 1,250 pounds, or 1,250 pounds. Assuming that the relative length of the lever arms of the beam 21, considering the pivot 22 as a fulcrum, is as one and a quarter to three, the sheave 19 will be raised upwardly with a force of 3,000 pounds, neglecting the weight of the beam 21 and connected sheaves. The tension upon the driving cables 16 on opposite sides of the sheave 19, due to the weight of the counterweight acting through the beam 21, is therefore equal to 1,500 pounds. Since the tension upon the left side of the driving cables due to the counterweight acting directly is 2,500 pounds, the total tension upon this side of the driving cables is 1,500 pounds 2,500 pounds 000 pounds. In a similar manner the tension upon the right side of the driving cables is equal to the weight of the empty car plus an upward pull of 1,500 pounds due to the counterweight, or 2,750 pounds. I With the usual conditions found in practice, a tractive or turning power may be applied at the contact surface of the drive sheave, equal to one half of the lesser tension on the leads extending from the drive sheave, before slipping will take place. In other words, the t'action may be one half of the lesser tension. The tension on the cables 16 at the right hand side being 2,750 pounds, the tension may be one half this amount or 1,375 pounds. The difference in the tension bet-ween the left and right hand cables with no load, is only 1,250 pounds. The traction required in lowering the car is therefore less than the minimum traction at which slipping will take place. Reasoning in a similar manner, if the car is loaded to its full capacity of 2,500 pounds, the total. weight on the right hand side will be 5.250 pounds, the lesser weight now being 000 pounds on the left hand side. The maximum traction required with a full load is therefore 1,250 pounds whereas a traction of 2,000 pounds might be applied before slipping would occur. If the car is loaded to half its capacity, the weight of the car with its load is equal to the counter-weight, so that the parts are balanced. It will thus be seen that with the parts proportioned as above stated, the traction will always be ample to prevent slipping and at the same time excessive strain is not placed on the cables. In many traction elevator systems the arrangement of parts is such that the ten.- sion on the cables is greatly increased by the addition of weight to the car. his increase in tension is frequently much more than t existing conditions warrant, and

merely results in excessive strain and'wear on the driving cables and other parts of the apparatus. In the example ust cited, the un balanced load to be moved will never exceed 1,250 pounds, consequently it is merely necessary to provide just sufficient tension on the cables to prevent slipping in overcoming this unbalanced load, together with the friction of the movin parts. If the pivoted beam 21 were removed and the tension upon the driving cables depended only upon the weights of the car and counterweight acting directly, the weight of both the car and counterweight would have to be greatly increased to prevent a variation in the load of 2,500 pounds without slipping of the cables.

From the foregoing it is readily seen that the pivoted beam 21 furnishes a simple and etlicient means for giving the requisite traction under all conditions of load without in any way complicating the system of roping or employing additional weights.

By varying the pivotal point of the beam 21 with respect to the sheaves 19 and 26, the mechanical advantage gained by having the counterbalance weight act through the lever arms of the beam may be widely varied with a corresponding variation in tension upon the driving cables 16. In this manner any desired traction may readily be obtained without varying the weight of the counterweight or any other part of the apparatus. The tension on the driving cables may also be regulated by varying the weight of the counterweight, a small addition in weight producing a relatively greater tension. Just what this ratio of increase will be depends upon the relative length of the lever arms of the pivoted beam.

With the arrangement of parts as shown, it is possible to exactly counterbalance the car and its average load and still be able to vary the tension on the driving cables without disturbing this balanced condition. This feature is of importance, in that a balanced elevator system represents the highest degree of efficient operation. It has been demonstrated in actual practice that our invention overcomes the bounding of an upwardly moving elevator car upon stopping the same, the tension upon the driving cables as well as the traction being momentarily increased at this time due to the momentum of the counterweight.

The foregoing applies with equal force to the arrangement shown in Fig. 2. In this case an additional weight IV is used which counterbalances a portion of the weight of the elevator car. Thus the entire weight of the car and its load is not utilized to produce a tension upon the tract-ion driving cables 16. The weight W should in every case be less than that of the car when the latter is empty, while the weight of the counterweight al may be as heavy as desired in order to secure the best results. As before pointed out, the car sheave 28 is supported upon the beam 21 and arranged vertically over the pivotal point 22 of the beam. Since this pivot point 22 is in vertical alinement with the pivot of the car sheave 28, the weight on this sheave is entirely supported by the beam and does not tend to tip the latter to vary the tension on the cables 16. While any tipping of the beam 21 would move the pivot of the car sheave 28 out of vertical alinement with the pivotal point 22 of the beam, and thus tend to vary the tension on the driving cables due to the leverage caused by the unbalanced weight of the car acting about the pivot 22 as a center, it is found in actual practice that the movement of the beam 21 about its pivot is so small that for all practical purposes it may be neglected.

This general description, together with the illustrations used in connection therewith, fully sets forth our invention, and the same may be adapted to any system of hoisting in which the car and its load are operated by means of traction driving cables. The motor may be of any suitable type, such as steam, hydraulic or electric, and may be controlled in any one of numerous ways well known in the art.

While we have shown a preferred embodiment of our invention, we desire not to be limited to the precise construction and arrangement of parts as shown and described, since .it is obvious that various changes could readily be made by those skilled in the art without departing from the spirit and scope of our invention,

What we claim as new and desire to secure by Letters Patent of the United States 1s:

1. In a traction elevator apparatus, the combination of a car, a counterbalance weight, traction driving cables, cable connections between the traction driving cables and the car and counterbalance weight, and

a pivoted beam associated with the counterbalance cable and the traction driving cables. 2. In a traction drive elevator apparatus, the combination of a motor, a driving sheave secured upon the shaft of said motor, endless driving cables associated with the driving sheave, an elevator car, a counterweight therefor, cable connections between the car, counterweight and driving cables for producing a tension in the driving cables, and further means for increasing the tension controlled by the counterweight.

8. In an elevator, the combination of a car, a counterweight, a motor, a traction sheave driven by said motor, a movable sheave, endless driving cables associated with the traction and movable sheaves, and means operated by the counterweight for raising the movable sheave in order to tighten the driving cables about the driving sheave.

4. In an elevator, the combination of a car, a counterweight, a motor driven traction sheave, a bodily movable sheave, endless driving cables including both sheaves, car suspension ables connected to the driving cables upon one side of the traction sheave, counterweight suspension cables connected to the driving cables upon the other side of the traction sheave, and an adjustably pivoted beam associated with the counterweight suspension cables and the bodily movable sheave.

In an elevator, the combination of a car, a counterweight, a motor, a traction sheave arranged for rotation by said motor, a pivoted beam, a cable sheave carried upon one end of the beam, endless driving cables associated with said cable and traction sheaves, and means for tilting the pivoted beam for the purpose of placing a tension upon the driving cables.

6. In an elevator, the combination of a car, a counterweight, suspension cables for the car and counterweight, a motor, a traction driving sheave arranged for rotation by the motor, a pivoted beam, cable sheaves carried upon opposite ends of the beam, endless driving cables associated with the traction driving sheave and one of the cable sheaves, the counterweight suspension cable leading over the other cable sheave, and means for securing the car and counterweight suspension cables to opposite leads of the endless driving cables.

7. In an elevator, a car, a counterweight, endless driving cables, cable connect-ions between the car, counterweight and endless driving cables, traction means for operating the endless driving cables, and means controlled by the counterweight for increasing the tension upon the endless driving cables, substantially as described.

8. In an elevator, the combination of a traction drive sheave, endless traction driving cables engaging said sheave, a car, a counterweight, cable connections between the endless driving cables, the car and the counterweight whereby the weights of the car and counterweight are transferred to leads of the endless driving cables extending from opposite sides of the drive sheave, and means for producing a further tension upon the endless driving cables controlled by the counterweight.

9. In a traction drive elevator apparatus, the combination of an elevator car, a counterweight, a motor, a traction sheave driven by said motor, a movable sheave, endless driving cables looped about the traction and movable sheaves, and means controlled by the counterweight for raising the movable sheave and thereby producing a substantially uniform tension throughout the endless driving cables.

10. In an elevator, the combination of a car, a counterweight, endless traction driving cables operatively connected to said car and counterweight, and means comprising a pivoted beam tor increasing the tension in the endless traction driving cables, the increased tension being controlled and etfccted by the counterweight acting through said pivoted beam.

11. In an elevator, the combination of a car, a counterweight, endless traction driving cables, a traction sheave arranged to operate said driving cables, cables connecting opposite leads of the driving cables to the car and counterweight respectively, and means controlled by the counterweight for producing a tension upon both leads of the driving cables.

12. In an elevator, the combination of a car, a counterweight, a motor driven trac tion sheave, a bodily movable tension sheave, endless cables including both sheaves, cables connecting the car and counterweight respcctively to opposite leads of the endless cables, a pivoted beam associated with the counterweight cable and the bodily movable tension sheave whereby the counterweight tends to tilt the pivoted beam and raise the bodily movable tension sheave.

13. In an elevator, the combination of a car, a counterweight, endless driving cables, cable connections between the car, counterweight and endless driving cables, traction means for operating the endless driving cables, means controlled by the counterweight for increasing the tension upon the endless driving cables, and an adjustable weight connected to the car for partially counterbalancing the same.

let. In a traction drive elevator apparatus, the combination of an endless driving cable, a car, a counterweight, cable connect-ions between the car, counterweight and driving :able, means in connection with the counterweight cable for producing a tension on the driving cable, and an additional weight for partially counterbalancing the car.

In testimony whereof, we have signed our names to this specification in the presence of two subscribing witnesses.

DAVID L. LINDQUIST. AUGUST SUNDH. lVitnesses CAMPBELL SCOTT, ROBERT J. SMITH.

Copies of this patent may be obtained for five centseach, by addressing the Commissioner of Patents, Washington, 1). C.

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