A worm-wheel gland is one that has an oblong flange similar to that in Fig. 991, and it has also a pair of screw-studs, similar in shape to the studs of other glands; the stem also of the gland is straight, and it is forced upon the packing in the packing-box in the usual manner. But the means adopted for applying the power to the screw-studs, differs from the ordinary hexagonal nuts and spanner, instead of which a couple of worm-wheels and a spindle are employed.

Worm-wheel glands are indicated by Fig. 1004. By referring to this sketch it will be seen that the screw-studs are fixed to the flange of the packing-box, in about the same manner as the studs of other glands; and that the upper ends of the studs pass through holes in the flange of the gland, the same as if hexagon nuts were to be placed thereon. But in the places usually occupied by such nuts, are placed a pair of worm-wheels having screwed holes in the bosses. These wheels may be termed a species of broad screw-nuts having worm-teeth on their rims instead of six planes. Both the wheels are rotated at one time by means of a worm-pinion or worm, engaged with the teeth of each wheel, both of these pinions being rotated at once because both are fastened on one spindle. The spindle is denoted by S, and has a square part at each end which fits the hole of a socket tee-spanner, such being used to effect the rotation.

By thus screwing down both the wheels at once, both ends of the gland-flange are forced down an equal distance with one rotation by the spanner; consequently the studs are not liable to be bent and broken, nor the flange bent or broken, which is liable to occur when only one end of a gland is operated upon at one time. The action of these glands is therefore the same as that of glands having six-sided flanges, or having notched flanges, similar to Figs. 984, 992, 993, and 995. But worm-wheel glands are more complicated by reason of the greater number of parts. It is therefore advisable to avoid using them whenever notched glands can be employed.

Those glands which have oil-cups connected to the flanges, and intended for vertical inverted engines, are represented by Fig. 1005. Such oil-cups are either cast solid with the flanges, or are cast separately and attached with small screws. The cup may have a lid and be connected with one side of the flange, as seen in the Figure, or it may be attached at one end, according to convenience. Oil-cups of this sort are supplied with oil by means of pipes of proper length, and having funnels at the ends, to allow oil to be given at any time, although the gland may be quite Viaccessible to the engineer.

Fig. 1006 represents one of the author's arrangements for inverted engines, which is available whenever the space around the packing-box will admit the free use of a spanner. By this mode two headed bolts are employed instead of two studs, the heads being beneath in contact with the gland-flange, and the nuts above situate on the flange of the packing-box. Through the nuts being thus located, their rotation with a spanner is much easier than if they were beneath in the places occupied by the bolt-heads.