Emery Needle Cushion on Sewing Machine

A convenient emery pad and needle cushion may be made by inclosing the powder in a long sack, about 1 in. in diameter, and sewing it in place around the arm of the machine. It will thus be close at hand and needles and pins may be stuck in the cushion, free from rust, and will not be in the way.

A Compensated Aerial Cableway
by Edward R. Smith

The possibilities for practical use as well as novelty for play and experimental purposes make the compensated aerial cableway, shown in the illustrations, not only interesting but also worthy of study. The arrangement assembled in its simplest form with two towers, in the [page plate], shows how the weight of the car is compensated, so that a fairly level course on the track cable is provided. The various positions of the load and cables, showing the application of the compensating principle, are indicated in [Figs. 1 to 5], and a multiple system is shown in [Fig. 6]. The details of the constructional parts are also shown. The car may be driven by wind power, as shown in [Fig. 7], or by a motor, as in [Fig. 8], in addition to the simple application of hand power suggested in the page plate. Devices for automatically reversing the course of the cars both for the sail rigging and with the use of electrical power, are shown in Figs. 7 and 8. By their use it is unnecessary to have an operator at each end of the cableway. The constructional features were worked out first by experiments on models in a shop, and then applied to a large rigging spanning over 100 ft. between the A-frames. The sketch in the page plate was made from photographs of this construction. Application of the compensating principle to carrying and transportation problems affords opportunity for interesting engineering, in spanning streams, caƱons, or gulleys.

In most types of cableways a considerable sag is allowed in the cable supporting the car in addition to that caused by its own weight. Even in systems of practically constant cable tension, in which the wire is stretched by enormous weights, the loaded car causes a sag in the track cable, and ascends and descends an incline when approaching and leaving a tower. The aim in the compensated cableway is to overcome this sag as much as possible, and to offer a minimum of resistance to the car in its course.

The simple form of compensated cableway shown in the [page plate] is made by setting up two A-frames, with wire braces supporting them, and mounting the track and traction cables upon them. A light, flexible compensating cable extends from one tower to the other and is fitted to grooved pulley wheels at the tops of the towers, as shown in the detail at the right. The ends of the cable are fixed to wire hooks, from which the track cable is suspended. The latter is anchored at the ends of the wire braces supporting the A-frames. In order to understand the operation of the system it is desirable that the course of a load be traced in its various stages, as indicated in the diagrams, Figs. 1 to 5. For diagrammatic purposes the load is shown passing from the west slope to the east. As the load passes under the first A-frame, as in Fig. 2, the track cable is drawn down at that point; the corresponding end of the compensating cable is also drawn down, raising the opposite end of the track cable, and taking out most of the sag in the center portion of the track cable. As the load passes to the center position, as shown in Fig. 3, the track cable resumes a more nearly horizontal position. When the second A-frame is reached the load draws the corresponding end of the compensating cable down with the track cable, Fig. 4, and the latter assumes its normal position as the load reaches the end of the course. It is evident from the diagrams that the course of the load is more nearly level than it would be if the sagging of the track cable were not counteracted.

For use with a multiple-frame system, the cables are arranged in units between supports, as shown in Fig. 6. The compensating action is similar, the tendency being to level the entire course of the load. The weight of the car and load only is compensated, and since the weight of the cable will cause a sag, the course cannot be level, but may approach this condition.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6

This Interesting Model Cableway was Built by a Boy for Play and Experimental Purposes: The Principle by Which the Weight of the Car is Compensated in Single and Multiple Systems is Indicated in the Diagrams Above. Cars Propelled by Sail Rigging or by a Small Battery Motor may Also be Used

A model of the compensated cableway, as shown in the [page plate], or on a smaller scale, may be made by a boy of fair mechanical skill. For experimental purposes the detail may, of course, be refined to a high grade of workmanship, if desired. The size and dimensions of the parts need not be proportioned precisely as shown, but may depend more or less upon the materials available. The track cable should be made of galvanized-iron wire, the compensating cable of fishline, and the towers of 1-in. stuff, the width of the pieces making up the A-frames being increased in proportion to the height. Grooved pulley wheels, set in housings fixed to the top of the A-frames, carry the compensating cable. These may be made of wood, built up in three sections, to provide a flange on each side of the cable groove. The A-frames should be joined strongly at the top, and braced to anchors, sunk into the ground as shown. The hooks from which the track cable is suspended are made of heavy wire, bent so as not to interfere with the H-frame hanger supporting the car, and looped around the cable.

Various types of hangers may be devised to house the two pulley wheels which ride on the track cable. A simple H-frame hanger is shown in the detail sketch in the [page plate]. The grooved pulley wheels are set on bolts, and a heavy wire is bent and set through the center block as a support for the car. For experimental purposes, or even for play, when it is not desired to make a more elaborate car, a wooden block or other object of sufficient weight may be used as a load. An interesting feature of the work, especially for a boy, is to devise a realistic coach model, as suggested in the sketch. A wooden block forms the base, and the roof and platforms are made of sheet metal. The windows and doors are painted on the metal. The inventive boy may, of course, build a car with a hollow metal or wooden body, and weight it properly to provide the necessary load.

The motive power is provided by means of a cord, or traction cable, carried around two large grooved pulleys, mounted in supports fixed to the landing stages at each end of the cableway. They are made of wood, a suitable groove being cut around the edge with a saw, and smoothed with a small round file, or sandpaper wrapped over a round rod. The traction pulley is turned by means of a crank, set on the bolt which is used as an axle. The traction cable must be drawn sufficiently taut to provide the necessary pressure on the grooved pulleys, or it will slip. Rosin applied to the pulleys and the cable will tend to prevent this.

Fig. 7

The Car is Propelled by the Wind Action on a Sail Controlled Like the Main Sheet of a Sailboat in Tacking. The Trigger Device Releases the Sail, Reversing the Course of the Car

If the frames and other fittings have been properly set up, the cableway will support a sail car, shown in [Fig. 7], or a two-cell electric car, driven by a small motor, as shown in [Fig. 8]. The sailing-car arrangement is often feasible, since a stiff breeze is common in gorges, caƱons, narrow valleys, or even in ravines where such a cableway might be set up. The hanger is an H-frame having the grooved pulleys bolted in it, and further reinforced by small blocks at the ends. A braced frame, supporting a deck on which a mast is set, is suspended from the hanger by four curved wires, as shown in the side view, Fig. 7. A sail with boom and gaff is supported by the mast. It is arranged to be shifted around the mast, which is accomplished automatically at the end of a run, or ā€œtack,ā€ by means of the trigger device shown in the top view. The sail is controlled in relation to the wind much as is the main sheet of a sailboat. The car can be operated in this manner only at right angles to the direction of the wind, or nearly so. For play purposes, a boy stationed at each end of the cableway can shift the sail, but the trigger device shown makes this unnecessary. A rubber band is attached to the boom, as indicated in the top view, and a cord and wire are arranged to engage a trigger. A stop for the trigger is fixed to the A-frame so that it is sprung when the car reaches the end of the run. The rubber band reverses the sail, the car having been set on the cable originally so that the forward end is in proper relation to the wind.

Fig. 8

The Electric Car Is Self-Contained and may be Reversed Automatically, if the Motor Is of the Reversible Type, by Contact of the Lever with the Stop Fixed to the A-Frame

The electric car is especially interesting in that it provides self-contained motive power by means of a battery of dry cells, and a motor belted to the hanger, as shown in [Fig. 8]. The hanger is of the H-frame type with heavy blocks between the sidepieces to provide for the small grooved driving pulley set on the axle of one of the larger pulleys. A wooden deck, supported by four heavy wires set into the center block of the hanger, carries the motor, and the dry cells are fixed under it. The motor is of the small reversible battery type, and should be provided with a reversing lever. This will make it possible to reverse the car when it reaches the end of its course. The motor and cells should be disposed so as to balance, tests being made for this purpose before setting them in place finally. A cord or small leather belt connects the drive pulley of the motor with the proper pulley on the hanger. These pulleys should be in line, and that on the hanger should be five times the diameter of the one on the motor shaft. The power is shut off at the end of the course by a shut-off switch which strikes a stop crank attached to the A-frame. When the reversing lever and stop are used, the stop crank is unnecessary. A nonreversing motor can be made to drive the car in a reverse direction by removing the belt from the motor pulley and replacing it to make a figure-eight twist.

Ā¶When babbitt metal is heated some of the tin and antimony in it is burned out, making it unsuited for use in machinery bearings, and similar purposes, after several heatings. The oxidation of the metal is indicated by the formation of a scum on the surface.

A Miniature Fighting
Tank
That Hurdles Trenches
By EDWARD R. SMITH

Among the engines of war in action on land, probably none has created greater interest than the now famous ā€œfighting tank,ā€ which, according to reports, pours out missiles of destruction on the enemy from armored turrets, and crawls over trenches, shell craters, and similar obstructions, like a fabled giant creature of prehistoric ages. The tank described in this article, while not as deadly as those on the battle fields of Europe, performs remarkable feats of hurdling trenches, and crawling over obstructions, large in proportion to its size. The model, as shown in the [heading sketches], is full-armored, and has a striking resemblance to these war monsters. The turret is mounted with a magazine gun, which fires 20 projectiles automatically, as the tank makes its way over the rough ground. The motive power for the tractor bands is furnished by linked rubber bands, stretched by a winding drum and ratchet device, on the rear axle, as shown in [Fig. 1]. When the ratchet is released, the rear axle drives the fluted wheels on it, and they in turn drive the tractor bands, as shown in the side elevation, [Fig. 6]. The wire-wrapped flywheel conserves the initial power of the rubber-band motor, and makes its action more nearly uniform.

The tank will run upward of 10 ft. on the rubber-motor power, depending on the size and number of the bands used. The gun is fired by a spring hammer, actuated by a rubber band. The trigger device is shown in [Fig. 1]. The pulley A is belted, with cord, to the front axle. Four pins on its inner side successively engage the wire trigger, drawing it out of the gun breech B, and permitting another shell to drop into place. As the pulley revolves, the trigger is released, firing the projectile. This process goes on until the motor runs down, or the supply of shells is exhausted.

The tank is guided by the pilot wheel, shown in [Fig. 1]. The sheet-metal armor, with its turret, is fitted over the mechanism, and can be removed quickly. It bears on angles bent up, as detailed in [Fig. 2], to fit on the ends of the wooden center crosspiece of the main frame, and is held by removable pins at the ends of this frame. While the rubber motor is easy to make and install, the range of the tank can be increased by using a strong spring motor, the construction otherwise being similar.

The construction is best begun by making the wooden frame which supports the armor. The perspective sketch, [Fig. 1], used in connection with the working and detailed drawings, will aid in making the latter clear. Make the frame C, as detailed in [Figs. 5 and 6], Ā³ā„ā‚ˆ by 1Ā³ā„ā‚„ by 11 in. long, with an opening cut in the center, 1 in. wide, 1 in. from the rear, and 1Ā¹ā„ā‚„ in. from the front end. Make the crosspiece D Ā³ā„ā‚ˆ by 1Ā³ā„ā‚„ by 5ā·ā„ā‚ˆ in. long; the gun support E, as detailed in [Fig. 4], Ā³ā„ā‚ˆ by 1āµā„ā‚ā‚† by 6Ā¹ā„ā‚„ in. long. Shape the support E as shown. Fasten the frame C and the crosspiece D with screws, setting the piece D 5Ā³ā„ā‚„ in. from the front, and its left end 3 in. from the side of the frame, as shown in Fig. 5. This is important, as the fitting of the other parts depends on the position of these wooden supports.

Fig. 3Fig. 4
Fig. 1
Fig. 2

Perspective Sketch, Showing the Arrangement of the Parts, with the Armor and the Tractor Bands Removed, and Details of the Gun Mechanism and the Armor

The drive-wheel axles are carried in sheet-metal hangers, F, shown in [Figs. 1] and [5], and detailed in [Fig. 6]. These hangers also carry bearing wheels, G, Fig. 1, which are held between the hanger F and a metal angle, as detailed at G, Fig. 6. These wheels are cut on a broomstick, and mounted on nail axles. The metal for the hangers F is drilled as shown, and bent double at the ends to make a strong bearing for the drive-wheel axles. The upper portion is bent at a right angle and fits over the top surface at the end of the crosspiece D, and is fastened to it with small screws or nails. Cut the stock for the hangers 2 by 6Ā³ā„ā‚ˆ in. long.

Next make the sheet-metal support H, [Fig. 1], for the flywheel, the rim of which is wrapped with wire to give it added weight. Cut the stock, as detailed in [Fig. 6], 1Ā³ā„ā‚„ by 4Ā³ā„ā‚ā‚† in. long, and notch it to form the spring arrangement, which holds the flywheel so that the belt will be tight. The other sheet-metal support may then be made also. Cut the stock for the front support J, for the rubber motor, 4Ā¹ā„ā‚ˆ by 3Ā³ā„ā‚„ in. long, and shape it as shown in the detail, Fig. 6. Make the support K from a piece of sheet metal, in general shape similar to that used for support H, the dimensions being made as required, and no spring arrangement being provided. Drill these metal fittings, as indicated, for the points of fastening, and mark the places for the holes in which shafts or axles run very carefully.

The driving mechanism can then be made, as shown in [Fig. 1], and detailed in [Figs. 5 and 6]. The driving shafts and their parts, as well as the pulleys, can be turned in a lathe, or made from spools, round rods, etc. Make the front axle L, and wheels, joined solidly, 5Ā³ā„ā‚„ in. over all, the grooved wheels being Ā³ā„ā‚„ in. thick, and 1ā·ā„ā‚ā‚† in. in diameter. Wires are used as bearings for shafts for the driving axles. If the rear axle is turned in a lathe, it is cut down to the shape indicated, thinner at the middle, to provide a place for the cord connected to the rubber motor. The grooved pulley and the fluted drive wheel at the winding-key end, shown in Fig. 5, are then cut loose; the drive wheel on the other end is cut loose, forming three sections, mounted on the wire axle, one end of which is the winding key. Ratchet wheels, M, are fitted between the ends of the center section and the adjoining pieces, the ratchet wheels being nailed to the center section and soldered to the wire axle. Pawls, U, are fitted to the inside of the two end sections, as indicated in Fig. 1 and in Fig. 5. When the rubber motor is wound up on the drum, the tractor bands are gripped until it is desired to start the tank on its trip. Then the power is communicated from the drum, or center section of the axle, to the drive wheels by means of the ratchet wheels, acting on the pawls.

Mount the hangers F on the center crosspiece D, fitting the axles of the drive wheels into place. Make the weighted flywheel, and mount it on its shaft, as shown, lining it up with the pulley on the rear drive shaft. Fit the supports J and K into place, setting spools for the rubber-motor cord in place, on wire axles. Arrange the belt from the flywheel to the drive shaft, and connect the rubber bands for the rubber motor as shown. Fasten one end in the hook of support J, and pass the winding cord through the spools, and fix it to the drive shaft. The device can then be operated with the fluted drive wheels, bearing on strips of wood for tracks.

The tractor bands N are fitted over the drive wheels, as shown in [Fig. 6]. They are built up of canvas strips, on which wooden shoes are glued and sewed, as detailed in [Fig. 5]. The stitches which reinforce the gluing are taken in the order indicated by the numerals. The pilot wheel is 2 in. in diameter, and sharpened at its circumference. Make a metal shell, O, for it, as detailed in Fig. 6. Solder the shell to the double wire, which supports the wheel and gives it a spring tension to take obstructions nicely. The wire is fastened to the crosspiece D, as shown in Fig. 5.

The gun and its mechanism can be made handily before the support E is fixed into place at the front of the crosspiece D. Shape the magazine P from sheet metal, making it 2āµā„ā‚ˆ in. high, as detailed in [Fig. 4]. Make the gun Q from a piece of sheet metal, as detailed, cutting the metal to the exact dimensions indicated. Mount the magazine and the gun, and arrange the wire hammer R, and the rubber band that holds it. Fit the pulley A into place on its axle, supported by a small block of wood. Belt it to the front drive-wheel axle, as shown in [Fig. 5], after the gun support is fastened into place with screws. Make the projectiles of wood, as shown, and the fighting tank is ready to be tested before putting on the armor.

The armor is made of one deck piece, S, [Fig. 3], into which the covered turret is set, and two side pieces T, as detailed in [Fig. 2]. Make one left and one right sidepiece, allowing for the flanges all around, to be bent over and used for riveting or soldering the armor together. The bottom extension on the sidepieces is bent double to form an angle, on which the armor is supported, where it rests on the top of the hangers F. The turret is fitted to the deck by cutting notches along its lower edge, the resulting strips being alternately turned in and out along the point of joining, as shown in Fig. 3. When the armor is completed, it is fitted over the main frame, the gun projecting from the turret. Small pins hold the ends of the armor solid against the ends of the main frame C, so that the armor can be lifted off readily. The various parts of the fighting tank can be painted as desired, care being taken not to injure the points of bearing, on the axles and pulleys, which should be oiled. Silver bronze is a good finish for the exterior of the armor, which may be decorated with a coat of arms.

Fig. 5
Fig. 6

Plan and Side Elevation of the Interior Mechanism, with the Armor Removed, and Details of the Metal Fittings, the Ratchets, and the Tractor Bands