US693467A - Lifting-bridge. - Google Patents

Description

'PatentedTeb. I8, 1902.

km. WADDELL', .LIFTING BRIDGE.

(Application filed Oct. 1, 1501.)

' 3 sheets--sheet I.

(Np Model.)

THE Noams PETERS 20. mom-LING" wAsmMuToN, D. c.

Patented Feb. 18, 1902;

In. wAooELL. LIFTING BRIDGE.

(Application filed on. 1.1901.

1 3 Sheets$haai 2.

(No Model.)

n4: nonms FETERS A0 PHOYO-LITNOH WASl-HNGTON, 5. (:4

-No. 693,467. Patented Feb. 18', I902.

m. WADDELL.

LIFTING BRIDGE.

v (Application filed Oct, 1, 1901,) (N muu l.) Y 3 Shuts-Sheet 3.-

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1 "UNITED STATES PATENT OFFICEI MONTGOMERY WADDELL, OF NElV YORK, N. Y.

LlFTING-BRIDGE.

srnornrcarron forming part of Letters Patent No. 693,467, dated February 18, 19.02. I

I l Application filed October 1,1901. Serial No. 77,181 (No model.) I

T0 ctZZ whom it may concern:

Be it known that I, MONTGOMERY WAD- DELL, a subject of the King of Great Britain,

residing in the city, county, and State of New York, have invented a certain new and useful Improvement in Lifting- Bridges, of which the following is a specification.

An ideal lifting or bascule bridge should present the following conditions: The tilting section of the bridge should be balanced so as to require a minimum of effort to move in all positions of the bridge, when fully raised the whole span width should be clear for passage of vessels without waste of room on the piers, and the entire bridge and its counterweight andoperating means should preferably remain always above ground, so as to avoid pits or cuttings in the abutments or piers.

It is the main object of my present invention to provide a lifting or bascule bridge presenting all the above advantages and at the same time to so mount and guide the counterweightthat it may be made as lightas possible, thus reducing the total weight of the moving structure, and thereby reducing its inertia and its first cost.

'My invention is illustrated in the accompanying drawings, wherein- V Figure 1 is a diagram illustrating the mathematical principles involved in my device for mounting and guiding the counterweight. Fig. 2 shows a form of bridge in which the exterior directing or limiting means is rigid. Fig. 3 shows a form of bridge wherein a flexible exterior directing means is employed. Fig. 4 shows a deck-bridge of the same class; and Figs. 5 and 6 are a top View and an end view, partly in section, respectively, of the preferred novel means for applying power to open the bridge.

7 In Fig. 1 the lower chord of a bridge is indicated at 1 in a half-raised position. The counterweightis shown at 2. A guide 3 is fixed to the bridge, so as to turn with it around the center of motion, which may be a pivot, as shown at 4. This guide carries the counterweight 2, which may be mounted thereon in any desired manner so long as the precise path of the counterweight is determined by said guide.

It is one of the fundamental principles of body 2.

my invention that a guide '3Yis employed to lead the weight 2 toward'thecenter of movement 4 of the bridge when said bridge tips upward and that this motion toward the cen' ter of movement is further determined byan exterior directing means, which may be arigid arm or, as preferred by me, a flexible cable. Where a cable is used, one end is anchored,

as at 5, to a point fixed upon the shore, the

other end being fixed to the counterweight. The cable passes over a pulley 6, preferably fi xed upon the bridge itself. This is the form intended to be represented in diagram in Fig. 1. In this form of bridge the counterweight acts in a dual capacity. It forms a movablepulley counterweight, since its supportingcable passes over a pulley movable with the inshore end of the bridge. At the same time instead of descending freely in a vertical line it is supported upon a guide 3, also on the inshore end of the bridge,-and by pressure upon said guide it acts as a direct counterweight.

If we assume the center of gravity of the bridge itself independently of the counter-f weight to be at a, the weight of the bridge being represented by the line W, and if the, t

vertical line through the center of movement be be, then ac is'the lever-arm of the downward or, positive turningmomentexerted by the weight W of the bridge. Now this turning moment is opposed by the two efforts into which the gravity of the counterweight 2 may be analyzed. The indirect elfortis that which is opposed by a stress in the cable 7. The direct effort is the simple weight w of the direction of this last or direct effort. Then if the line df be a. continuation of the direction Supposethe vertical line ole to represent in length and direction the quantity and.

assumed by the cable 7 near the weight 2 and a perpendicular ef is drawn to a line dg tangent to the guideway 3 at the point occu-' pied by the weight 2 the line df will represent by its length the stress in the cable 7. By drawing a-perpendicular to theinshore direction of the cable 7 from the point 4 the lever-arm 4 is obtained, which multiplied by the stress df (called 8) gives the turning moment of said stress tending to tilt the bridge. The line 61) is the lever-arm of the direct efiort exerted bythe body 2, and the moment is found by multiplying the weight of the body 2 by the arm 61). Now in order to avoid all resistance to movement of the bridge either way directly due to its weight the following equation should be true:

. Where IV is the weight of the bridge, to is the ance the counterweight can be made quite small relatively, and even in such a case as that shown in Fig. 4:, for example, this weight may be made less than that of the bridge.

Inspection of Fig. 1 will show that as the tangent (lg to the guide approaches the ver-' tical (which it does when the bridge closes) the perpendicular cg will cut the line dffarther and farther from d, and this increase will take place faster than the decrease in the lever-arm eh of the direct effort. Thus is secured an increased indirect effort, giving an increased total negative turning moment to correspond and counterbalance the increasing positive moment of the bridge as it approaches the horizontal.

In the arrangement indicated in Fig. 3 a counterweight 1.32 times the weight of the bridge will snffice.

It is of course to be understood that while a perfect neutral balance is desirable over a large part of the total opening and closing movements circumstances will usually make it desirable to depart from this condition at certain points in the travel of the bridge. For instance, it may be desired to balance the bridge so that it has aslight closing or downward tendency near the entirely open position. This causes a gentle stop, avoiding shock as the opening bridge comes to rest and giving a ready return when the bridge is to be closed again. On the other hand, it will often be well to produce the same effect in or near the closing position, so that there is a certain tendency of the bridge to open when closed. Appropriate locking devices of any age 9. On the end of this arm is the counterweight 2, running upon a guide 3 of suitable form. As will be seen from the dotted lines in Fig.

2, the counterweight is made to run of this device are explained hereinafter;

down along the guide 3 to a position near the center of movementa of the bridge. The contrary movement occurs on closing the bridge. In, this form of bridge, as in the others, the span is clear from pier to pier and all parts of the bridge and its accessories are above the pier-head, as shown. This form of my invention may be used with advantage in deck-bridges.

Fig. 3 exhibits the very simple form to which a practical bascule-bridge is reducible when made in accordance with my invention. Here a cable 7 is used, running over the pulley 6, while the counterweight attached to the end of said cable runs in a guide 3 of very simple curved form. In the form actually shown this curve is the arc of a circle. As shown in dottedlines, when the bridge is open the counterweight is brought near to the center of movement 4:. In this figure Ihave shown a preferred means for applying power in opening the bridge. This consists in an operating-arm 10, pivoted to a fixed anchorage 1.1 and carrying at its movable extremity gearing 12, adapted to work in a rack 13, conveniently placed upon the bridge. The details Inspection of the parts of Fig. 3 shown in dotted lines will indicate the relative movements of the bridge and its operating-arm.

In Fig. 4 is shown a deck-bridge provided with a preferred form of my invention wherein a counterweight actually lighter than the bridge structure may be used. In this form two movable pulleys ('3 and 6 are used, and the weight 2 runs in a substantially straight guideway. The anchorage of the cable 7 is accomplished through the operating-arm 10, to the extremity of which it is fixed. The location of the pulley 6 is such that before the gearing 12 comes opposite the pulley the cable 7 acts to aid in tilting up of the bridge, and when said gearing advances materially beyond the pulley 6 said cable tends to retard movement of the bridge. These effects can be made to correspond, respectively, to a time before and after the center of gravity reaches a vertical through the center of movement 4:- The gearing 12 is made to turn in the rack 13 for operating the bridge by means of any appropriate motor either on the bridge or elsewhere; but I prefer to use a motorstanding upon or near the pier, as shown at 14:. The means for transmitting power from such a motor to the gearing 13 are illustrated in detail in Figs. 5 and 6. The arm 10, pivoted at 11, carries a primary gear 15, which drives the shaft 16 by any means such, for instance, as the bevel-gears 17 and 18. The gear 15 may be driven in any desired wayas, for instance, by the pinion 19 on the shaft of an electric or other motor 14. The shaft 16 turns in suitably-placed bearings 21 and extends to the outer end of the arm 10, where it carries a bevel-gear 22, meshing with a like gear 23 to drive a shaft 24:, carrying a pinion 12. This pinion meshes with the rack 13, carried This isnecessary'toallow free turning'of the wheels 29at all times. Thepinin12should- 'haveteeth deep enough to permit of move-; 5

" withoutcausingdisengagement; Itwillbe un-r 7 in any suitable manner on the bridge. I prefer to confine the pinion 12 by some such Here the c'hannel-bar carries the rack '13 on its upperv means as shown in Fig. 6:

side, while tracks 26' and 27 run along inside the bar 25 on both sides. .A frame 28 car- .ries the outer bearing of the pinion 12 and i also carries the pulleys 29, adapted to moon oneIor the other of the tracks 26 27 In Fig. 6

is shown thesmallcleara'nce' maintainedbetween one or the other track and these wheels.

mentofthe pulleys 28: from a track to track derstood that the wheels 29 will run upon o'ne or the othe'rof the tracks provided, according Y to whether a pull or a, push is exerted in the armlO. The frame or carriage 28 is.-pivoted upon the hub 30, carried bythe extremity of the arm 10,1:0 accommodate the-varying angle I between these two incident 'to movement of the bridge.

- Avar-iety of operating] means maybe em ployed with my improved;bridge and many other modificationsmay'be made in theforms herein specified without departing from the spirit of myinvention. Iam therefore not to be understood as limiting-myself to the precise details herein shown and described.

WhatI claim isv 1. In a bascule-bridge,a coun terw'eight and a guideway for the same fixed on said bridge and extending upward from near the center of movement of said bridge when the same is closed.

2. In abascule-bridge, acounterweight, a guideway for said counterweight onsaid bridge extending upward from near the center of movement of said'bridg'e when thesame is closed and means attached outside of said bridge for directing the movement of said counterweight upon said guide.

3. In a bascule-bridge, a counterweight, a

. guideway therefor on the bridge and a flexible cable anchored'ontside of the bridge for limiting the movement of'said counterweight upon said guide. I Y

4:- In a bascule-bridge, a counterweight, means fixed to said bridge for guiding said ingto support said connterweight. n r a I I 5. In abascule-bridge, .a counterweight, a guideway therefor fixed to'the bridge, aflexi counterweight, and a flexible cable-cooperatj v 55. blecableattached" tosaidcounterweightand 1 anchorcd'outside'of' the bridge and a-pull'ey counterweight, and 'a'guideway fixed-to said on the bridgexover which said cable passes. 6. In a lbascule-cbridge, a1 m0vable+pulley i .60

bridgefor'g-uidingsaid counterweight.

7 In a basculeebridge, a'fcounterweight, a

flexible cable attache'dto saidcounterweight' at onevend and anchored attheotherlendand 1 3 to thebridge making a varying angle withw f said cableduringimovementofthebridge;- I 8. In means for raising bas'cule-bridges, ah] anchorage, a connectingdevice rotatably fixed thereto for transmitting the operating a guiding means for saidcounterweight fixed strain and power -t'ransmitting .means. an

tached to the end of said'connecting device directlyj tending to makesaid end travel along'a predetermined path on said bridge. 9. In a means for raising bascule-bridges,

gear and means anchored pivotally outside of said bridge carrying said gear.

. 10. In a means for raising bascule-bridges,

a rack on the bridge, a traveling gear-wheel engaging therewith, a pivoted operating-arm carrying said gear-wheel, a motor outside of said bridge and transmitting means between said motor and gear-wheel carried by said operating-arm.

11. In a bascule-bridge, a counterweight,

va guideway therefor, two pulleys onsaid bridge and a flexible cable passing over said pulleys and attachedto said counterweight and to an anchorage outside of said bridge at its two ends respectively,

arackon' the, bridge, a traveling gear-wheel engaging therewith, a motor forturning said 12. Ina bascule-bridge,a counterweight,

a guideway therefor, two pulleys on-the bridge, a pivoted operating-arm and a flexiother end to said operating-arm..

MONTGOMERY VVADDELL. Witnesses: r

ABRAHAM GOLDSHEAR, H. S. MAOKAYE.

ble cable passing over said pulleys attached at one endto said counterweight and at the

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