Old Type
Figs. 254 and 255 show the construction of the old type Philadelphia Diamond Grid. Battery. Figs. 254 and 256 show the diamond shaped grid from which the battery derives its name. It is claimed that this construction gives a very strong grid, holding the active materials firmly in place, and giving a large amount of contact surface between the grid and the active material.
Figs. 254 and 255 show the old type battery, and give the details of the cover, terminal posts, vent plug, and so on. The post seal is made tight by pouring the compound into the cover well so that it flows in around all of the petticoats on the post.
This construction increases the distance that the acid must travel along the post, in order to cause a leak, about two and one-half times the vertical distance on a smooth post. The hard rubber washer which fits around the post acts as a lock to prevent the post from turning. This applies especially to the two terminal posts to which the cables are attached. The washer is intended to prevent any strain in the cable from turning the post and breaking the seal between the post and the compound.
New Development in the Philadelphia Battery
Rubber Lockt Seal Covers. During the last few years there has been a marked tendency in the battery industry to do away with the use of sealing compound for making a joint between the cell cover and the terminal posts and to substitute a mechanical seal of some kind at this joint. The Philadelphia Storage Battery Co. has developed the "Rubber Lockt". cover seal, the construction of which is shown in detail in Figs. 256 and 257. On the cell posts there is a. flange which supports the cover, and above this there is a recessed portion into which is slipped a soft rubber sleeve or bushing. This portion of the post is made with a ridge extending around the post and with the rubber sleeve forming a high point over which a corresponding locking edge in the terminal hole of the cover is snapped. This construction makes a joint which is flexible and at the same time acid tight. Vibration tends to push the cover down on the supporting flanges, as the post diameter is smaller below the locking edge. The design is simple, both from the assembly and the repair standpoint, as no tools are required for either operation. In the assembly operation the groups are lined up so that the post centers are correct and, after wetting the soft rubber sleeves, the cover is snapped in place with a quick downward push. See Fig. 258. In removing the covers, catch under each end with the fingers and pull upward, at the same time pressing with the thumbs on the top of the posts. See Fig. 259.