US741786A - Trolley-stand. - Google Patents

Description

'No. 74l,786. BATBNTED-OGT.20;"1903.

J. J. GOODRIGH, & J. H. MQPHERS'ON.

TROLLEY STAND.

APPLIQATIONIILED NOV. 20, 1902.

I .2 SHEETS-SHEET 1.

.110 MODEL.

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NITED lPatented. October 20, 1905.

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JOHN J. GOODRIGH, OF METHUEN, AND JAMES H. MCPHERSON, OF HAVER- HILL, MASSACHUSETTS, ASSIGNORS or ONE-THIRD To WILLIAM R. PED- RICK, OF LAWRENCE, MASSACHUSETTS.

TROLL EY-STAN D.

SPECIFICATION forming part of Letters Patent No. 741,786, dated October 20, 1903-. Application filed November 20, 1902. Serial No. 132,110. (No model.)

This invention relates to certain improvements in that class of trolley-pole stands in which the pole is'mounted so that it may swing horizontally and vertically and in which springs are provided for forcing the 1 wheel borne thereby against the wire.

So far as we are aware in trolley-pole stands now in general use the tension on the spring which acts to force the trolley-wheel against the wire is increased as the pole is drawn down, and thus increased force is transmitted to the trolleywheel, which is consequently-pressed against the wire with much greater force when the wire is hung low or close to the car than it is when the wire is at the normal distance above the car.

The increased force with which the trolleywheel is pressed against the wire when the wire is hung close to the top of the car, as in passing under bridges or in subways, greatly increases the normal wear upon the wire, wheel, and wheel-bearing.

Trolley-stands in general use are so constructed also that the means for lifting the pole extend fora considerable distance in front of the aXis of the support upon which the pole is pivoted, so that their inertia is so great, particularly by reason of the distance to which they extend {from the center about which they swing, that the ready swinging of the trolley-pole as it follows the wire is at first retarded thereby, and then the acquired momentum tends to throw the trolley-wheel from the wireas its movement is arrested.

The principal objects of our invention are 5 to provide a form of trolley-pole stand in which a constant tension is placed upon the pole whatever its vertical position and in which the parts which act to lift the pole are arranged closely adjacent the axis about which the pole-support swings. We accom- 5o plish these objects in the manner hereinafter described and as illustrated in the accompanying drawings, in which- Figure 1 is a side elevation of a trolleypole stand made according to our invention. Fig. 2 is a plan View, partly in section, on the line a: on, Fig. 1. Fig. 3 is a longitudi nal cross-section on the line 31y of Fig. 4. Fig. at is a cross-section on the line 2 2, Fig.

1, with the water-shield partly broken away. Fig. 5 is a plan view with certain other parts also broken away. Fig. 6 is a diagrammatical view.

The base a of the stand, which is secured to the top of the'car, is provided with an annular ball-race a in the upper side thereof, in which a series of balls I) are arranged. Said base is also provided with an outwardlyprojecting portion a having a horizontal upper surface. The pole-support c is prefer- 7c ably of inverted-cup-shaped form, as shown in Fig. 3, and has an annular ball-race c in its lower side, which is the complement of the ball-race o', in which balls I) are also located. Said support is also provided with a circumferential flange c having an annular ball-race c on its upper side of greater diameter than the ball-races a c and in which the balls 01 are also located. An annular plate e is arranged above flange c and is provided with an annular ball-race e in its lower side, which is the complement of the ball-race c of the support 0.

A series of capscrewsf pass freely through the plate e and are threaded into the upper side of the projecting portion a of the base a, and a series of set-screws g are threaded in the plate 6, and their lower ends bear against the upper horizontal surface of the projecting portion (1 as indicated in Fig. 3. 0 By this means the plate a may be rigidly held in any position within certain limits and may be so adjusted as to prevent all looseness of the bearing between the plate and support, thereby holding the support rigidly in its 5 vertical position, yet permitting its free rotation. It will be apparent that to tighten this bearing it is simply necessary to unscrew the set-screws g and take up on the cap-screws f, and to loosen it the cap-screws must be loosened and the set-screws screwed down.

A water-shield h is secured by screws 7; to an annular seat formed on the upper side of the support 0, a packing-washer is preferably being interposed between the shield and the support, so that access of water to the hearing is effectively prevented.

The support 0 is provided with two upwardly-projecting ears 0 0 to which the trolley-pole lever Z is pivoted by means of bolts m, which are secured in saidears and pass through the arms Z at one end of the lever. The opposite end of said lever is provided with a socket in which the trolley-pole p is secured by suitable means, said pole bearing the usual trolley-wheel at its end.

A horizontal rod or spring-holder it passes through a central aperture 0 formed in the body of the support 0 midway between the ears 0 0 said rod 17. being rigidly secured to the support in the normal plane of movement of the pole by a pin 0, which passes through the support and rod.

An adjustable stop-nut q is threaded on the front end of the rod 02, and a spring 7' is interposed between said nut and a sliding collar or yoke 5, located on the rod '12 between the support 0 and said nut. A second sliding yoke s is arranged on the rod n at the opposite side of the support 0 and is free to slide thereon, said yokes s s being rigidly connected by a pair of rods 25 25, which pass through aperture 0 in the support, said rods having shoulders against which the adjacent sides of said yokes bear and clamping-nuts at their opposite sides. A second spring r is arranged on the rod it between the yoke s and a yoke u, also slidably mounted on said rod, and the arms Z of the lever Z are connected to said yoke by a pair of rigid rods or links 0 0), which are pivoted at one end to the arms Z by means of pivot-bolts m, the opposite ends of said links being screwthreaded and passing through apertures in the yoke u. Nuts '0 v are screwed on said threaded ends and arranged in front and in the rear of the yoke a, respectively. The apertures in the yokeu are made large enough to permit a certain swinging movement of the links therein, each nut '0 on the rear side of the yoke being provided with a spherical or rounded face, and the bearing-surfaces therefor on the yoke are correspondingly shaped, providing, in effect, a pivotal connection between the yoke and each link, the centers of which are in the center of the apertures in the yoke and in the center of the spherical or rounded seats of the nuts on the yoke. As the springs r r are confined between nut q and yoke u and the rigidly connected yokes s s are interposed between said springs and are free to slide on rod 7%, the result is that said springs act as a single spring in forcing the trolley-wheel upward.

A buffer-spring r is interposed between the yoke u and a stop-nut g at the rear end of the rod 72.

In Fig. 1 the parts are illustrated in their normal position with the trolley-wheel running in contact with a trolley-wire hung'at the usual height. The usual distance between the trolley-wire and the top of the car is about seven feet; but in subways and under bridges the wire is often hung within nearly a foot of the car. In some places the wire must be hung more than seven feet above the top of the car, so that the trolleywheel may have to be pressed against the wire within a vertical distance of six or seven feet. In this normal position the center of the pivots m, which connect the links with the lever, are preferably on a level with the horizontal center line of rod a. As the force which acts to draw the pole down acts vertically and the force of the springs rr acts on the lever-arms Z in a direction parallel or coincident with a straight line between the pivotal points at each end of links 12 o, it follows that the effective length of the short arm Z of lever] is equal to the length of a perpendicular line from the fulcrum of the leverZ or the center of pivots m to the longitudinal center line of links 4) o, whatever the position of the latter, while the effective length of the long arm of the lover or pole end is equal to the length of a perpendicular line from said fulcrum to the vertical line through the axis of the trolley-wheel Whatever the position of the wheel. As the trolley-wheel is forced down the effective length of the short arm of the lever is decreased, while that of the long arm is increased, with the result that the mechanical advantage of the trolley-wheel over the springs r r is rapidly increased as it is lowered. The springs are compressed, and therefore their tension is also rapidly increased, as the wheel is moved down; but by correct adjustment of the parts, as now to be explained, we succeed in cansing the increased tension of the springs to be exactly overcome by the increased mechanical advantage of the trolley-wheel as'it is drawn down, with the result that the wheel is always pressed against the wire with the same force whatever its position within the ordinary limits ofmovement of the pole above referred to.

. In designing and constructinga device with which the above results may be secured the arms of the lever are first made of such relative'lengths that when a spring of desired strength is employed the wheel will be forced against the wire with substantially the force required. In practice the distance which the horizontallyrunning trolley wire is hung above the pivot of the lever varies within approximately certain normal limits, and these limits are ordinarily such that the pole is required to swing through an arc the approximate limits of which are from about five degrees to sixty-five degrees above the horizontal. The pivotal point between the IIO I links and yoke moves in a path which is substantially horizontal. In order that the efiective length of the short arm of the lever may grow shorter in direct proportion to the increased tension on the spring as it compressesit, it is essential that the pivotal points between the links and short arm and that between the link and yoke shall always be located on opposite sides of the line which indicates the position of the short arm when it is perpendicular to the linkthat is, the limits of the path of movement of the pivotal point between the link and short arm in which the short arm will have an equalizing effect on the varying tension of the spring as it is compressed are the positions where the short arm and link are perpendicular and where they are coincident or dead. The are between these limits we may term for convenience the arc of equalization. It follows, therefore, that in order to secure the desired results the angular relation of the short and long arm and the relative length of the short arm and location of the path of movement of the pivotal point between the link and yoke must be such that the line of the short arm is always within this arc of equalization, while the long arm or pole is between its normal vertical limits.

Owing to the variation in tension of diiferent springs, we have found it to be impractical to make the arrangement above described perform its intended function without ad' justment.

Having designed the above-described device with all possible accuracy, the manner in which we adjust it'so that we may accomplish the above-described result and the reasons why such adjustments will accomplish this result may be best understood by reference to the diagrammatical view shown in Fig. 6. In this figure, 1 indicates the fulcrum of lever Z, and 2 the horizontal line or plane in which the pivotal points between the links 2; o andthe yoke it move as the lever swings on its fulcrum. 3 and 4 respectively indicate the position of the pivotal points between the u when these parts are in the normal position,

links U o and the lever-arm l and the yoke (shown in Figs. 1 and 3,) with these points sume the position of line 6, connecting the' "points 3 and 4:, then the effective lengthof the lever-arm Z in this position will be equal to the length of the perpendicular line 7 from fulcrum 1 to line 6. If in moving the lever to the second position just described, thereby lowering the trolley-wheel, it is found that the upward pressure at the wheel or the force with which it is pressed against the wire is Assuming, for example, that the stop-nuts v -q are screwed back on the rod n or toward the support 0 for a certain distance and the nuts '0 are screwed back on the links v 'u an equal distance away from the support, so that arm of the lever will be measured by the length of the perpendicular line 9 from the fulcrum 1 to the line 10, connecting the point 8 and the point 3'. By swinging the points of intersection of the perpendicular line 7 with the line 6 and line 9 with line 10 through arcs having the fulcrum 1 as the center, so that said arcs intersect the same radius, it will be seen that the effective length of the. short arm of the lever has been decreased for this position at 3, so that the mechanical advantage of the trolley-wheel over the springs is, in effect, increased, with the result that the wheel is forced against the wire with less force than when the pivotal point of the links and yoke was atet. By readj ustin g the parts so that the pivotal point between the links and yoke is moved to the point 11 at the other side of point 4:, for example, the effective length of the short arm ofthe lever will be increased instead of diminished. By this means it will be seen that we are enabled to vary the effective length of the short armof the same lever within necessary limits by a simple adjustment without varying the tension of the springs, so that .when the trolley-wheel is moved either up or down to its normal limits from an intermediate position the upward pressure on the trolley-wheel will not be varied to an appreciable extent, and the wear on the wire, trolleywheel, and wheel-bearing will be uniform whatever the height of the wire.

The force with which the wheel is pressed against the wire may be increased without varying the relative adjustment above described by screwing the nut q rearwardly on the rod and nuts 11 forwardly on the links the nuts 7 0 on the links will engage the front IIO for an equal distance and may be diminished 'of, as has been customary, so that the inertia of these parts in our device is less effective in retarding the free swinging movement of the pole on the car than it is in the prior construction.

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent, is

1. A trolley-pole stand having a support, a lever pivoted on said support, atroll'ey-wheel on the long arm of said lever, means comprising a spring for pressing said wheel upward against a horizontally running wire hung at varying distances above the stand, and for equalizing the varying tension of said spring to produce a substantially uniform upward pressure of the Wheel against the wire as it is moved between its normal vertical limits, comprising a yoke actuated by said spring, means for guiding said yoke horizontally, a link pivotally connected to said yoke, and to the short arm of said lever, the angular relation of the arms of the lever and the relative position of the path of the pivotal connection between the link and yoke being such that the pivotal point between said link and short arm is constantly within its arc of equalization While the trolley-wheel is within its normal vertical limits, and means for varying the length of said link without varying the tension on said spring, substantially as described.

2. A trolley-pole stand having a support, a

lever pivoted on said support, a trolley-wheelon the long arm of said lever, means comprising a spring for pressing said wheel upward against a horizontallyrunning wire hung at varying distances above the stand, and for equalizing the varying tension of said spring to produce a substantially uniform upward pressure of the wheel against the wire as it is moved between its normal vertical limits, comprising a horizontally-disposed spring-holder encircled by said spring and mounted on said support, an. adjustable stop mass on said holder for one end of said spring, a yoke slidably mounted on said holder and engaged by the opposite end of said spring, a link pivotally connected to the short arm of said lever and to said yoke, means for varying the length of said link, said parts being so arranged that the pivotal point between said link and short arm is constantly located at opposite sides of the right-angular position of the short arm with relation to the link in all positions of the wheel within said normal vertical limits, substantially as described.

3. A trolley-pole stand comprising a support, a pole-carrying lever fulcrumed there- ,in, spring-holders arranged in alinement on opposite sides of said support, springs mounted thereon, a sliding connection between the adjacent ends of said springs, a stop for the opposite end of one of said springs, and a connection between said lever and the opposite end of the other spring permitting said springs to act to lift the pole, substantially as described.

4. A trolley-pole stand comprising a support, a pole-carrying lever fulcrurned therein, spring-holders arranged in alinement on opposite sides of said support, springs mounted thereon, a yoke slidably mounted on each holder between the adjacent ends of said springs, a rigid connection between said yokes, a stop for the opposite end of one spring, a connection between the opposite end of the other spring and the pole permitting the springs to act to lift the pole, substantially as described.

5. A trolley-pole stand comprising a support, a pole-carrying lever fulcrumed therein, spring-holders arranged in alinement on opposite sides of said support, springs mounted thereon, a yoke slidably mounted on each holder between the adjacent ends of said springs, a pair of rigid rods firmly secured to each of said yokes, astop for the opposite end of one spring, a connection between the opposite end of the other spring and the pole permittingthe springs to act to lift the pole, substantially as described.

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

JOHN J. GOODRIOl-I. JAMES H. MOPHERSON.

Witnesses: I

LoUIs H. HARRIMAN, H. B. DAVIS.

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