US1254772A - Bascule-bridge. - Google Patents

Description

T. E. BROWN, la.

BASCULE BRIDGE.

APPLICATION FILED mum. 19x1.

Patentfl Jan. 29; 1918.

4 SHEETS-SHEET 1.

I w 5 nvawl'oz T. E. BROWN, In.

BASCULE BRIDGE. I APPLICATION FILED IAN-31,1911.

Patentw Jan. 29, 1918.

4' swans-smear 2.-

T. E. BROWN, 1R. BASCULE BRIDGE.

APPLICATION FILED JAN. 31- 19H.

Patented Jan. 29, 1918.

4 SHEETS-SHEET 3.

4 SHEETS-SHEET 4;

Patented Jan. 29, 1918.

T, E. BROWN, 1;. BASCU LE BRIDGE.

APPLICATION FILED JAN. 31. 1917- lltl till

THOMAS ELLIS BROWN, The, Oh MOBRISTUWN, NEW JERSEY.

JBCULJE-BRIJDGE.

Specification of. Letters Fateut.

Patented Jan. $9, Tm,

Application filed January 31, 1917. Serial No. 145,578.

To all whom it may concern:

Be it known that l, TnoMAs Farms BROWN, Jr, a citizen of the United States, and a resident of Morristown, in the county of Morris and State of New Jersey, have invented certain new and useful Improve- --ments in Bascule-Bridges, of which the following is a specification.

This invention relates to improvements in bascule bridges.

The simplest form of bascule bridge is the ordinary heel counterbalanced trunnion type and this form is usually adopted when the height of the bridge above the water is suficient to admit of its use. In many situations, the height is insufficient for the heel of the bridge and counter-balance to clear the water or tops of the piers, and then the span must be made longer in proportion to the width of the Waterway and a. water tight pit must be provided into which the heel of the bridge and counterbalance may descend. The expense of construction in such cases becomes very great, and therefore the more complicated .and unsightly types,

with towers and counterweights above the roadway, are usually resorted to.

Cases frequently occur where the height above water is not suflicient for a simple heel balanced bridge of ordinary type-without watertight pits, and yet where the use of unsightly towers and counterweights would be very objectionable, and also in ordinary heel counterbalanced trunnion bridges it is necessary to so dispose the counterbalance that the center of gravity of the entire moving mass will coincide with the center of the trunnions or pivots, and this usually requires the placing of a considerable portion of the counterbalance above the bridge deck, to the detriment of the appearance of the structure; and it is the object of my invention to produce a heel --balanced trunnion bridge, suitable for such cases, in which coincidence of the center of grayity and the pivot is unnecessary and therefore no counterbalance 'need be placed.

above the deck of the bridge and by which the use of water tight pits or unsightly towers'is entirely avoided.

To accomplish this, I prefer to partially balance the bridge by heel counterbalance,

using as much' heel counterbalance as the height above water will conveniently permit,

and complete the balance of the) moving span by means of a counterweightlsups ported on a beam pivotally connected at one end to the .heel' or rearwardly projecting end of the bridge, and supported at its other end by a roller or truck which rolls forward and backward on a suitable track as the bridge opens and closes. This construction is especially useful when concrete is used for counterbalance, which is now the general practice, as, on account of its great bulk, concrete counterbalance is very clumsy, and unsightly when placed above the bridge floor.

Referring to the drawings which accompany the specification to aid the description:-

Figure '1 is a side view of cording to my construction.

Figs. 2 and 3 are diagrams explanatory of the principles of my invention.

Figs. 4 and 5 show details of special cases.

Fig. 6 shows my invention applied to a bridge of therolling type.

Fig. shows my invention applied to. a truss bridge with trunnions above the roadway, and V Fig.- 8 shows my invention applied to a search light tower.

Similar letters of reference refer to similar parts in all the figures.

Referring to Fig. 1, B is a bascule bridge P the pivot or trunnion about which it rotates, A, A A are piers and D a portion of the fixed structure supporting said a bridge acpivot P. Other parts of the fixed structure v the bridge, and rotating with the W is a counterweight supported on a beam 0 which is pivotally connected to the,

heel or rearwardly projecting end of the bridge at a suitable point ll. 1

The inner or rearward end of said beam C, which may be considered as an extension to said counterweight, is supported on the axle E of a roller K, said roller K being free to move forward and backward on a track T as the bridge B opens and closes.

The center of gravity G of said weight W, including.the weight of said-beam C,

thearrangement is such that the weight W or heavy mate- 7 is preferably located on the line TE, and

balances the bridge B, together with the 'heelcounterbalance H, in all its positions,-

as is hereinafter explained in connection with Fig. 2.

The point 0. g. is the position of the center of gravity of the combined weights of the bridge B and heel/counterbalance H. Said center of gravity may be brought by choice of the amount of the counterbalance H to as near to the pivot P as is convenient, and hereinafter we will for brevity use the i0 term bridge as referring to the total mass, including the counterbalance H, rotating about the pivot P. G is the center of gravity or center of mass of the counterweight W, which we will refer to hereinafter as the center G to avoid confusion with the center of gravity 0. g. of the bridge.

F and F are respectively fixed and movableportions of the roadway or bridge floor and Z is the break in. the floorbetween them, which, as well as the heel counterbalance H,"are preferably so located as to clear the top of pier A, when the bridge is in a vertical position.

It will be understood that the description refers to one side of the bridge only and that the parts described will in general be duplicated on the other side of the bridge,

but the ,heel counterbalance H and the counterweight W may extend clear across the bridge if desired. I

The bridge may be operated in any suitable manner, butI prefer to use a gear segment S secured to the bridge and meshing with a pinion U-on shaft V, supported on a 85 fixed part of the structure; said shaft V may be rotated by any suitable gearing and power.

When said pinion U is rotated in the direction the reverse of the hands of a clock, the river end of bridge B rises and the heel end descends, the beam C and weight W also descend, and the roller K travels horizontally along the track T, and when the pinion U is rotated in the opposite direction the bridge B, descends and the weight W rises.

The track T may be supported in any suitable manner, as by the masonry of pier A as shown in Fig. 1 or by structural members, or-

BO may be hung from or supported on the girders above.

Now referring more especially to Figs. 2 and 3, having determined the position of the center of gravity 0. g. of the bridge (including the heel counterbalance H) and the total.

"weight corresponding to said center of gravity,I place the pivot I preferably on the line fi om 6.9. through thepivot P and at a convenient distance, R from said piv'ot P. I

. then locate the counterweight Win a convenient position making-fits weight in a suitable ratio N to'the total weight of the bridge B including the heel fcounterbalance H. -I then draw a line through the pivotI and thecenter of gravityGof the weight description of Fig. 3',"and it should be noted ity c. g. of the bridge divided by the ratio I have discovered that when'the point I is placed in line with the center of gravity of the bridge, 0. g. and the pivot P, there is 30 a point 0 on the line IG or on'said line prolonged, which will move in a horizontal path when the weight W moves in the said proportion; and therefore any mechanism which will constrain said point 0 to move in a horizontal path during the opening and closing of the bridge will cause said weight W to move in said proportion, and balance thebridge in all its positions.

If we make R=the radius from pivot P to 0. g. R -the radius from pivot P to I. N=the ratio of the weight W to the a weight of the bridge B (including the heel counterbalance H). X=the distance from pivot I to the center G of the weight W, and Lzthe length along the line IG from pivot I to the required point 0, then the relationship between these quantities is given by the equation 'terial element of the structure. Ihis will be more clearly understood, from the following that the law expressed"by the hereinbefore given formula, i s entirely independent of the form or type of mechanism used to control the motion of the counterweight W.

The motion of the counterweight W rela tively to the horizontally moving theoretical point 0, is a motion of pure rotation. I therefore define said point 0 as the theoretical axis of rotation of the counterweight or more briefly the theoretical axis, to dis- 180 taaerra tinguish it from the material axle E with whlch it may or may not coincide.

The construction as described for Fig.1 with the center E of roller K coinciding with said point 0, and with the .track '1 horizontal, is the simplest way of constraihing the point U to move in a horizontal line and is the construction which I prefer Whenever practicable; but cases may arise, (see Fig. 3) where on account of interferences of fixed portions of the structureor other reasons it is desirable to lace the roller K at some other point than t e point 0.

lln such cases, as in Fig. 3 Where the bank Q of the stream or canal prevents the roller K being placed at point O, we may place said roller K at some other point, as for instance E, or even at a considerable distance from O, as point K, as may be most sfiitable to the particular design. In such cases the track can no longer beperfectly horizontal but must be inclined or curved in order to constrain the point 0 to move in a straight horizontal line. I

We can readily describe the path of'the center E of the roller K for any position of said center E relatively to line I-'G after having determined L by the formulae ll prefer to do this by locating various positions of the theoretical point 0 along its horizontal path by describing arcs of length L from the corresponding positions ll, i

2' 2', etc., of point l for various movements of the bridge, see Fig. 3, and then by draw- P ing intersecting arcs from these points '0,

0, 0 0*, etc., and the corresponding points ll, 11, i i of radii equal to the distances 0. E and l[. E respectively, locate the corresponding positions, E, 6 0 a 6 etc., of the axle E of the wheel K, a line passing through the points thus found will be the path of E. y

By a similar constructionwe may find the path of the roller for any position as for instance K of which the path is 78 10 It, etc. It will be noted that the shape of the path is quite different for difl'erent positions of the roller K relatively to point 01 Thus for position E it is concave upward, while for position K" it is convex upward.

in the diagrams, Figs. 2 and 3, the beam C connecting the roller K to the weight W is omitted for .clearness. It will be noted that in the cases shown in Fig. 3 the point U will not lie on the actual structure but will be a theoretical point in space.

VVhere for any reason a part of the fixed structure as floor beam ill, (see Fig. 5) may interfere with the direct connection of beam C to pivot l or necessitate an awkward construction, we may. but only when the track 'l perfectly is horizontal, connect the end of beam C to pivot l by means of a vertical hanger M, for as long as the roller K travels Also it may be applied t0 a rolling bridge as shown in Fig. 6. In such cases,

till

The distribution of counterbalance between the heel of the bridge and the counter- Weight W depends on the conditions of each particular case, and in some cases it may be desirable to place all of the counterbalance in the weight W, but it will be understood that, after the length L from pivot l to pointO has been established for a given ratio N, that ratio cannot be changed without varying correspondingly the other factors R, R and K in the above equation.

My invention is not limited to cases where the counterbalancing devices are placed below the floor ofthe bridge, though especially valuable in such cases, for the weight W,

beam 0 and roller K may be placed above said deck and the invention applied to a through truss bridge as shown in Fig. 7. ba'scule I prefer to make the weight W sutliciently heavy to completely balance the bridge, without the use of heel counterbalance.

lit should be noted that the axle E of beam C can be fixed in position and the pivot P of the bridge be supported on rollers and said pivot P and entire bridge move forward and backward instead of the axle E, and the conditions of the equation will still be fulfilled, but ll prefer the arrangement shown in Fig. 1 with the pivot lit will often be found convenient to place the track and rollers K on the girders of the approach span as shown in Fig. t using a long link M to support the end of the beam C. In such cases I prefer to use a truck with two or more rollers K instead of a single roller, and if, as may be the ease in small bridges, only an approximate balance is required we may dispense with the toilets K and track '1 and hang the end of the beam C by a long link M pivoted on the approach girders at a suitable point Y.

If the length of the link M -is great so that the are of its swing is very flat the balancewill be quite accurate, but an approximate balance sufficiently closefor small bridges may be obtained with a link of reasonable length as in.;Fig. at;

it will be understood that in small bridges or bridges where the load at axle E is not great, a simple sliding shoe may be used instead of a roller or truck;

While my invention is especially intended for bascule bridges it may be used with other structures of a similar nature as for instance a movable Searchlight tower as shown in Fig. 8.

ll do not confine myself to the precise mechanism described and shown. but consider that any mechanism which will constrain a theoretical point 0 as defined herein connected by a pivot to said span, a roller to travel in a horizontal linejis within the scope of my invention.

Now having described my improvementsI claim as my invention,

1. In a bascule bridge, a. counterweight, a. beam supporting said counterweight and connected by a pivot to the rearwardly extended end of said bridge, a roller supporting said beam and a-substantially horizontal track supporting said roller;

2. In a bascule bridge, a counterweight, a beam supporting said counterweight and connected by a pivot to said bridge and having itsrearward endsupported by a track adapted to guide said endof said beam in a substantially horizontal path during the opening and closing of thebridge.

3. In a bridge the combination of a movable span, a counterweight, a beam supporting said counterweight and having one end supporting the other end of'said beam and a substantially horizontal track supporting said roller. I

4. In a bridge the combination of a movable span,"a counterweight, a beam supporting said counterweight and having one end directly connected by a pivot to the rearwardly projecting end of said span, a roller supportlng the other end of said beam track supporting said roller.

5. In abridge the combination of a movable'span, a counterweight, a beam supporting said counterweight and having one end connected by a pivot to said span, a roller supporting the other end of said beam and a track supporting said roller and adapted to cause the theoretical axis as described-to move in a horizontal line during the opening and closing of the span.

6. In a bridge the combination of a movable span, acounterweight, a beam supporting said counterweight. and having one end to said span, a ,track supporting the other end of said beam and adapted to cause the theoretical axis as described to move in a horizontal line during the opening and closing of the span.

7. In a bascule bridge, a counterweighh a beam supporting said counterweight and pivotally connected to the rearwardly extended end of said bridge and means adapted to guide the projecting end of said beam in a substantially horizontal path so that the center of gravity of said counterweight will have a vertical movement proportionalto I the vertical movement of the center of gravity of saidbri'dge.

8. In a bascule bridge, a counterweight pivotally connected to said bridge at a point opposite the center of gravity of said bridge relatively to the pivot of said bridge, a rearward extension from said counterweight and a substantially horizontal track adapted to support and guide said extension.

anda' 9. In a bascule bridge, a counterweight, a beam supporting said counterweight and pivotally connected tosaid bridge at a point opposite the center of gravit of said bridge relatively to the pivot 0 said bridge, a

wroller supportingsaid beam and a track said bridge and the pivot of said bridge, an

axle supporting said beam and means adapted to cause said axle to travel in a substantially horizontal line during the opening and closing of said brid e.

11.. In a bascule bridge, a counterweight connected by a pivotto the rearwardly extended end of said bridge, an extension from said counterweight, a roller supporting said extension, a substantially horizontal track supporting said'roller, and said roller being at a constant distance from said pivot such that the vertical movement of said counterweight is always proportional to the vertical movement of the center of gravity of said bridge.

12. In a bascule bridge, a counterweight,

a beam supporting said counterweight andpivotally connected at one end to said bridge, and means adapted to constrain the other end of said beam to move in a path such that a point on the line passing through said pivot and the center of gravity of said counterweight and distant from said pivot as described will move in a horizontal line when the bridge opens and closes.

13. Iii 'a'bascule bridge a counterweight connected by a pivot to said bridge and means adapted to control the movement of said counterweight so that a point on the line-passingthrough said pivot and the center of gravityof said'counterweight and at a distance from said pivot as described will move in a horizontal line when the bridge opens and closes.

14. In a bascule bridge, a counterweight connected by a pivot to said bridge and 'means adapted to control the movement of said counterweight so that a point .on the line passing through said pivot and the center of gravity of said counterweight, said point situated at a distance from said pivot equal to the ratio of the weight or said counterweight to the weight of the bridge multiplied by the distance from said pivot to the center of gravity of said counterweight and divided by said ratio minus the ratio of the radius of the path of the center of gravity of said bridge to the radius of the path of said pivot, will move. in a horizontal line.

15. In a bascule bridge, a pivoted span, a counterweight, an axle for said counterthrou h said span on the line center of gravity of sand span'and the axis mama/a weight, a pivot connectin weight to said span on t e line passing the center at, gravity of. said span and t epivot of said Spain-and means to permit said axle to moveiorward' and. backward as said span is raised and lowered.

16. In a bascule-bridge, a movable span, a counterweight, a beam supporting said-- counterweight and connected l0 by'a plvot to said span on the line passing through the center of gravity of said span and.v the axis of said span, and means to enable said axle to move forward and backward'as said span is opened and closed. I

17. In .a bascule bridge, a counterweight, a beam counterweight and connected by a p1vot to passing through the a movable span,

said co'unteran axle supporting said beam supporting said of said span, an axle supporting said beam,

a roller and track supporting said axle and.

adapted to permit said axle to move forward and backward and lowered. v 5

18.'i;=][n a bascule bridge, a movable span, a counterweight mounted upon an axle, and connected by a pivot to said span on the line passing through the center of gravity of said span and the axis of said span, and means to allow said axle to I and forward in a substantially horizontal line when said bridge is opened, and closed. Signed at New York city, in the county of New York, and State of New York, this 29th day of January, A. D. 1917.

I THOMASELLIS BROWN, JR. Witnesses: WILLIAM PAmnsoN,

WALT R N. a

travel backward as said span is raised I xii:

Images