Gamewell Fire Alarm Tel. Co. v. Municipal Signal Co.

52 F. 471, 1892 U.S. App. LEXIS 1925
CourtU.S. Circuit Court for the District of Massachusetts
DecidedAugust 10, 1892
DocketNo. 2,543
StatusPublished

This text of 52 F. 471 (Gamewell Fire Alarm Tel. Co. v. Municipal Signal Co.) is published on Counsel Stack Legal Research, covering U.S. Circuit Court for the District of Massachusetts primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Gamewell Fire Alarm Tel. Co. v. Municipal Signal Co., 52 F. 471, 1892 U.S. App. LEXIS 1925 (circtdma 1892).

Opinion

Colt, Circuit Judge.

This bill in equity alleges the infringement of letters patent No. 164,425, dated June 15, 1875, issued to Stephen Chester. The invention relates to an improved form of signal box for the transmission of fire-alarm or other electro-telegraphic signals. The mechanism is somewhat complicated. It is only necessary in this case to particularly examine that part of the contrivance covered by the third claim. The Chester signal box has within the case an interior box which is described as containing a combination of gear-work capable of causing any electrical circuit closing and breaking devices to move with uniform speed, when the weight or spring necessary to produce motion shall be attached thereto and shall be wound up. The patentee further says:

“It has been customary to use clock-springs inclosed within this circular box, C, for impelling the said machinery, which, in very cold weather, are liable to fracture, or to inequality of motive force when subjected to greatly varying degrees of temperature; hence, in many parts of the country, demands have been made to have weights substituted to drive the machinery, which operate outside the box, 0. The objection to this latter mode of propulsion has been that the method of winding up the machinery has been such that the weight would be raised with a sudden, impulsive motion, frequently [472]*472catching in the upper corner of the box, or.its attachment to the arm, D2, would be broken. This difficulty would be obviated if the method of winding were such that the weight would be raised with a steady and uniform motion.”

The third claim has reference to the winding apparatus. A bell-crank lever is fixed upon the end of a shaft, and by revolving actuates the transmitting machine. One arm of this lever is attached to a weight, and the other arm is made in the form of a cogged sector or wheel, the teeth of which engage with a pinion. This pinion is so held upon a shaft that it can slide thereon in a longitudinal direction, and revolve loosely upon it. To the end of the shaft is fixed a disk, and the pinion is normally pressed towards the disk by a spiral spring surrounding the shaft. The shaft is also pressed outward by a spiral spring within its standard, which standard is fixed to the side of the box. The shaft is prevented from being thrown out from its bearing by a screw which normally rests in a longitudinal groove upon the surface of the shaft. In this position the shaft cannot be rotated, but the groove permits the shaft to be pressed backward against the force of the spring behind it until the screw is opposite a transverse groove surrounding the shaft, and when in this position the shaft can be rotated. Upon the cessation of pressure upon the spring the shaft will return to its normal position. On opposite sides of the door of the box are two plates, and held between them is a ratchet wheel which is engaged by a pawl, and so permitted to revolve only in one.direction. The keyhole is cut through the plates, ratchet wheel, disk upon the end of the shaft, and into the pinion. The key is so shaped that when pressed in the proper distance it will revolve, and will turn with it the ratchet wheel, disk, and pinion, and thus permit the shaft to rotate. When the key is thus rotated the pinion winds up the transmitting mechanism, and the ratchet wheel prevents the key being rotated in the reverse direction, or withdrawn from the box, before the full rotation of the pinion and the winding up of the motor. The results accomplished by this form of apparatus are stated by the patentee, as follows:

“It is equally evident that, if the proper key be introduced and turned in the only direction permitted by the ratchet wheel, H, it will cause the weight, S, to be raised, or an equivalent effect be produced if a spring be used. Also, it is evident that the key must make an entire revolution before the pin, e, can escape from the transverse groove, d, into the longitudinal groove, c, of the shaft, 3?. When, however, this revolution has been performed, precisely as one would lock or unlock a lock, if no severe pressure be made upon the key at that moment it will be thrown out by the recovery of the spring under the shaft, 3?, and so soon as the points of the key escape from the slot or keyhole of the pinion, the latter, being entirely free, will be caused to revolve in the opposite direction .by the descent of the weight, S, and consequent movement of arm, D1, and the key cannot re-engage in the said slot or keyhole until the revolution of the pinion has again brought the keyholes opposite to each other. * * * When the key has once been turned and thrown out, as above described, it is impossible to reintroduce it, or in any way interfere with the evolutions of the interior machinery, until it has completed the functions assigned to it.”

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Bluebook (online)
52 F. 471, 1892 U.S. App. LEXIS 1925, Counsel Stack Legal Research, https://law.counselstack.com/opinion/gamewell-fire-alarm-tel-co-v-municipal-signal-co-circtdma-1892.