Grooved Joint

Grooved Joint, - This is formed by means of a groove, as, for instance, when piles or cylinders for submerging are cast with vertical lateral indented grooves, into which plates of timber or iron are slid to form a temporary or permanent barrier to the passage of water.

Grouped Riveted Joint

Grouped Riveted Joint occurs when two or more layers of main plates are used in one thickness, as in

Fig. 86, with the view of collecting as many joints as possible under one pair of cover plates. Each butt joint must be so arranged as to lie as far as practicable from the others, and to be at the same time well within the cover plates.

Hinge Joint

Hinge Joint is made when the connected parts are fastened with a pin or bolt constituting an axis, and allowing play or motion to ensue within definite limits around it. Out of many forms may be mentioned that which occurs when hinged shoes consisting of steel, cast iron, or gun-metal bearing plates, with an interposed pin, are fixed over the points of support to enable girders to ride and transmit their resultant pressure centrally down columns or equably over expansion or bearing rollers, as in Fig. 70. In the case of arched ribs, the bed plates of the hinged joints are built vertically into the abutments, as shown in Fig. 87, the hinge forming a provision against small longitudinal changes.

Hook Joint

From numerous applications of the hook in jointing may be selected that occurring in fireproof floors when interties are secured by bending their ends into the form of a hook so as to pass up by the side of the web, and then over the top of the girder so as to give it lateral strength, whilst other cross bars are hooked on to these at right angles to them so as to form a network of rodding to receive concrete or plaster.

Hook Joint 86

Fig. 85.

Hook Joint 87

Fig. 86.

Hook Joint 88

Fig. 87.

Horizontal Joint

This necessarily occurs at, and is identical with, a level joint in cisterns, bridge piers, and other cast iron structures.

India-rubber Joint

India-rubber Joint is made by inserting rings of vulcanised india-rubber in pipe sockets to render them water-tight. The plan does not appear to be popular for large pipes, but in the case of low-pressure water pipes for heating conservatories, etc, a short tube or long cylindrical ring of this material is stretched over the spigot, which is then pushed into the faucet, and if thick enough to well fill the cavity, will make a perfectly tight joint as soon as the water circulates. Joints, however, of this nature must not be made too near the heating. apparatus, pure caoutchouc fusing at about 360° Fahr. Flat rubber rings make a good joint also between flanges.