Dean Receiver

Of such decided novelty as to be almost revolutionary in character is the receiver recently put on the market by the Dean Electric Company and shown in Fig. 55. This receiver is of the direct-current type and employs but a single cylindrical bobbin of wire. The core of this bobbin and the return path for the magnetic lines of force set up in it are composed of soft iron punch ings of substantially E shape. These punch ings are laid together so as to form a laminated soft-iron field, the limbs of which are about square in cro -section. The coil is wound on the center portion of this E as a core, the core being, as stated, approximately square in cro -section. The general form of magnetic circuit in this instrument is therefore similar to that of the Automatic Electric Company's receiver, shown in Figs. 52 and 53, but the core is laminated instead of being solid as in that instrument. IMG:384091999325875926_fig055_t.gif.png:Illustration_ Fig. 55. Dean Steel Shell Receiver Fig. 55. Dean Steel Shell Receiver View full size illustration. The most unusual feature of this Dean receiver is that the use of hard rubber or composition does not enter into the formation of the shell, but instead a shell composed entirely of steel stampings has been substituted therefor. The main portion of this shell is the barrel 1 . Great skill has evidently been exercised in the forming of this by the cold-drawn proce , it presenting neither seams nor welds. The ear piece 2 is also formed of steel of about the same gauge as the barrel 1 . Instead of screw-threading the steel parts, so that they would directly engage each other, the ingenious device has been employed of swaging a bra ring 3 in the barrel portion and a similar bra ring 4 in the ear cap portion, these two being slotted and keyed, as shown at 8 , so as to prevent their turning in their respective seats. The ring 3 is provided with an external screw thread and the ring 4 with an internal screw thread, so that the receiver cap is screwed on to the barrel in the same way as in the ordinary rubber shell. By the employment of these bra screw-threaded rings, the rusting together of the parts so that they could not be separated when required—a difficulty heretofore encountered in steel construction of similar parts—has been remedied. IMG:384091999325875926_fig056_t.gif.png:Illustration_ Fig. 56. Working Parts of Dean Receiver Fig. 56. Working Parts of Dean Receiver View full size illustration. The entire working parts of this receiver are contained within the cup 5 , the edge of which is flanged outwardly to afford a seat for the diaphragm. The diaphragm is locked in place on the shell by a screw-threaded ring 6 , as is clearly indicated. A ring 7 of insulating material is seated within the enlarged portion of the barrel 1 , and against this the flange of the cup 5 rests and is held in place by the cap 2 when it is screwed home. The working parts of this receiver partially disa embled are shown in Fig. 56, which gives a clear idea of some of the features not clearly illustrated in Fig. 55. It cannot be denied that one of the principal items of maintenance of subscribers' station equipment has been due to the breakage of receiver shells. The users frequently allow their receiver to fall and strike heavily against the wall or floor, thus not only subjecting the cords to great strain, but sometimes cracking or entirely breaking the receiver shell. The innovation thus proposed by the Dean Company of making the entire receiver shell of steel is of great interest. The shell, as will be seen, is entirely insulated from the circuit of the receiver so that no contact exists by which a user could receive a shock. The shell is enameled inside and out with a heavy black insulating enamel baked on, and said to be of great durability. How this enamel will wear remains to be seen. The insulation of the interior portions of the receiver is further guarded by providing a lining of fiber within the shell at all points where it seems po ible that a cro could occur between some of the working parts and the metal of the shell. This type of receiver has not been on the market long enough to draw definite conclusions, based on experience in use, as to what its permanent performance will be. Thus far in this chapter only those receivers which are commonly called hand receivers have been discu ed. These are the receivers that are ordinarily employed by the general public. IMG:384091999325875926_fig057_t.gif.png:Illustration_ Fig. 57. Operator Fig. 57. Operator's Receiver View full size illustration.