The joint occupies the minimum of space and is of very pleasing appearance.

The fibrous rings of the joint are held in place by annular shoulders or projections cast on the inner side of the spherical enlargement, as shown in Figs. 536, 537 and 538, the projections extending inward far enough to nearly touch the outer surface of the spigot. The upper surfaces are bevelled so as to guide the spigot centrally when it is inserted into the cup.

In order to provide properly for the longitudinal movement of the pipes under the influence of changes of temperature or shrinkage and settlement of the building the spigot is first lowered into the bell end of the pipe below until it touches the shoulder at the connection of the cylindrical enlargement with the main pipe. The pipe is then lifted a short distance corresponding with the amount of play room desired. To enable this play room to be easily attained in setting the pipes, and to regulate its amount with exactitude, and absolutely independent of the skill or scientific attainment of the journeyman plumber, the mechanism shown in the cuts has been devised. The stack is supported by hangers surrounding the pipes just below the external shoulders of the cylindrical enlargements below the cups. The hangers are placed in contact with shoulders when the spigot end of the pipe has been brought in contact with the inner shoulder of the cupped end. The upper pipe is then raised from the shoulder until the free space below the spigot has attained the exact size required for the best results, by driving a wedge of iron between the bell shoulder and the hanger, the thickness of the wedge being the gauge of the proper space required. The pliable compound is forced in after the proper adjustment has been made, and the joint is completed.

Figs. 540 to 547 show the construction of the Securitas ball and socket joint designed to provide for rotary movement.

The joint has the same exterior form and the same pliable compound for packing as the straight pipe joint, but one-half of the spherical space between the bell and socket is filled with a fine Portland cement and sand concrete cast upon the spigot to form the ball of rotation, a sheet metal disc separating this hard from the soft packing.

In this joint the mouth or opening of the cup is a little larger than the exterior diameter of the spigot end, so as to receive the same, and also leave room for considerable lateral play when the inner pipe is rotated around the centre of the cup as an axis.

In order to enable the Portland cement to take as perfect a spherical form as possible without going to the expense of machine turned work the interior surface of the cup is coated with asphaltum at the factory in the usual manner, and it is provided, also at the factory, with a further coating of paraffin by dipping. These two coatings produce a very smooth inner surface thick enough to fill up all the rough irregularities of the casting with a comparatively soft material, so that when the concrete sphere is cast therein and has hardened a perfect ball and socket joint is formed with the paraffin for a lubricator, which is capable of rotation without injury to either part. The force required to rotate this joint is small compared with those which are brought to bear upon the pipe system by the expansion and contraction of the. iron or by the shrinkage or settlement of the building. The softness of the paraffin lining permits the pipes to rotate under a comparatively small leverage of pipe length. To permit of the sheet metal disc being inserted in the cup it is cut across so that it can be bent into the form of a spiral and easily inserted into the cup around the spigot as a corkscrew would be inserted. The disc is inserted at the pipe factory before the pipe is coated with asphaltum. The coating then covers not only all parts of the pipe but also the disc on both sides, and serves to bind the disc securely to the inner side of the cup and hold it firmly in position while the spigot end is being introduced through the hole in the disc, besides making a tight partition between the two kinds of cement when they are forced into the joint.

The Securitas Flexible Joint 578

Fig. 540.

The Securitas Flexible Joint 579

Fig. 541.

Flexible gaskets are used in this joint in the same way as in the plain pipe Securitas joint to retain the packing compound. The gaskets are made slightly larger than the spigot end, in order that the latter may be easily introduced into them. When the pliable compound is forced into the joint the gaskets are pressed firmly in place around the end of the spigot, as shown. One gasket is placed just above the end of the spigot, and another higher up, so as to bear against and make tight with the sheet metal ring, as shown in Figs. 540 and 542.

The Securitas Flexible Joint 580

Fig. 542.

The Securitas Flexible Joint 581

Fig. 543.

The Portland cement is first inserted either in a rather thick or stiff state through the opening around the bell or in a thinner or fluid state through a special threaded opening shown in Fig. 544. The pliable compound is afterwards inserted in the manner already described after the Portland cement has set, the small threaded plug inserted, and the joint is complete.

The larger the pipe the smaller, comparatively, the amount of cements required. Thus in a street main, shown in Fig. 548, the joint takes up relatively a much smaller amount of room than in a small plumbers' pipe, shown in Fig. 540.

For calking large street mains the pressure may be economically and very quickly applied by steam pressure, a portable boiler and steam pump being moved from joint to joint, the boiler providing the energy both for pumping and locomotion, the only hard labor necessary consisting of opening and closing a valve after connecting the hose with the joint, and then capping up the supply nozzle.

The Securitas Flexible Joint 582

Fig. 548.

The Securitas Flexible Joint 583

Fig. 544.

Figs. 541 to 547, inclusive, show a method of the writer's for obtaining bends in piping of considerable angle without employing special fittings and without producing uneven interior surfaces or pockets: Two small bevelled rings are placed in the joint under the spigot, under the spigot end. When it is desired to set the two pipes in straight alignment, so that the axis of one shall be a continuation of that of the other in the same direction, one of the small rings is placed upon the other in such a position that their two inclined edges shall exactly offset each other; or, in other words, that the widest side of one ring shall come over the narrowest side of the other, making the arrangement shown in Fig. 542. When, on the other hand, it is desired that the two pipes shall be set at the greatest possible angle with each other, the relative arrangement of the two small rings is exactly the reverse, the two wide sides coming over each other. An intermediate arrangement of the rings will produce an angle in the pipe alignment intermediate between the two.

The Securitas Flexible Joint 584

Fig. 545.

The Securitas Flexible Joint 585

Fig. 546.

Fig 547.

Fig 547.

In order to facilitate the setting of the pipes in the exact angle desired without protractors or guesswork, figures are cast on one of the rings, Fig. 546, which denote the exact number of degrees the upper pipe will slope beyond the straight line when the small arrow cast on the other ring, Fig. 545, is placed over that particular figure. Thus, if the arrow is placed over the sign O, the axis of the two pipes will form no angle with each other, and the pipes will be known to be in exact alignment. If the arrow is placed over the figure 5, the pipes will incline with each other at an angle of exactly 5 degrees, and the pitch thus attained may easily be carried up as high as 10 or 15 degrees, producing, in the case of large street mains, a considerable degree of convenience and economy. The degrees between 0° and 50 and between 50 and 10° and between 10° and 150

The Securitas Flexible Joint 587

Fig. 548.

may be designated by simple notches in smaller pipes, and the small rings have cup and spigot edges not only to insure accurate setting but also to permit of the use of small gaskets to serve as barriers for the escape of the hard and soft cements when forced in to make up the joint.

If the Portland cement is to be applied in a liquid state it is necessary that the annular opening of the cup around the spigot pipe should be temporarily closed in order to prevent the escape of the cement. Figs. 541 and 544 show a form of mechanism we have designed to effect this easily and quickly.

The small sleeve, shown in Fig. 541, around the spigot end has for its object to permit of both a longitudinal and a rotary play in the same joint, a complication, however, which in practice might never be required. Small perforations in this sleeve permit the elastic filling compound to fill the space between the sleeve and the pipe.

Thus we have obtained the flexible joint long needed for safety, convenience, and economy. It permits of the safe use of "Standard" in place of "Extra heavy" thickness in pipes, as explained in the note on Pages 694 and 695. The very great saving in the weight of the pipe and in the making up of the joints reduces the cost of this system of piping to less than half that of the ordinary barbarous and unreliable bell and spigot joint now in vogue.