US 2172066 A
Description (OCR text may contain errors)
Sept 5, 1939. B. LOGSDON ANNOUNCING SYSTEM FOR SHIPS Filed July 21, 1937 INVENTOR.
ATTORNEYS WITNESS. 1 f I Patented Sept. 5, 1939 ANNOUNCING SYSTEM FOR SHIPS Lewis B. Logsdon, New York, N. Y.
Application July 21, 1937, Serial No. 154,721
This invention relates to sound reproduction and more specifically to audio amplifier announcing systems for use on ships.
One of the main features of sides in utilizing the metal hull vey audible sounds throughout the invention reof a ship to conthe ship by mechanical vibration at all voice frequencies.
Whereas the advantages of a system of sound reproduction of the above kind may have many advantages, the system will be found most useful for emergency purposes to publicly notify the crew and passengers of a ship regardless of their whereabouts of fire drills, actual impending dangers affecting the safety of the ship at sea, and the paging of individual passengers and crew aboard the ship.
frequencies in the circuit for imparting corresponding vibratory frequencies to the ships hull, thus utilizing the ships hull as a vibratory loud speaker.
With these and other objects in view, the invention resides in the certain novel construction,
combination and arrangement sential features of which are of parts, the eshereinafter fully described in the following specification, are particularly pointed out in the appended claims, and are illustrated in the accompanying drawing in which Figure 1 is a transverse sectional view through a ships hull with my invention with.
associated there- Figure 2 is an enlarged fragmentary sectional View of one of the impact striker units.
Figure 3 is an enlarged horizontal sectional View on the line 3-3 of Figure 2.
Figure 4 is a vertical sectional view on the line 4--4 of Figure 2.
Figure 5 is a detail perspective view of the shutter valve plates in separated relation.
Figure 6 is a detail vertical sectional view of a modified form of the invention.
Referring to the drawing by reference characters, the numeral lfl'designates a metal ships hull and l I an inner wall structure such as watertight bulkheads, arranged in spaced relation to the hull. Mounted within the ship is a compressed fluid storage tank I2 which may contain air or other fiuidpressure.
A predetermined fluid pressure is maintained in the storage tank l2 by a motor driven compressor I3. Connected to the storage pressure tank I2 are fluid pressure distributing pipes I4 which extend throughout the lengthof the ships hull and to which branch pipes l'5' are suitably connected. In Figure 1 of the drawing, I have shown four of such branch pipes [5, the same'extending horizontally through the inner Wall structure [I and being arranged in pairs on opposite sides of the hull. It will be understood'that any number of branch pipes may be provided throughout the area of the hull' for individual connection with impact striker units I 6- now tobe described.
Each impact striker unit includes a rectangular casing l1 bolted or otherwise secured to the outer side of the inner wall structure II so as to be disposed within the space between the hull l0 and the inner wall structure. The outer side of the casing is'provided with converging walls !8 which meet the inner ends of an open ended cylinder 19. The casing H is provided with an air inlet opening 2|] joined by a branch pipe l5; and'which inlet opening is disposed in axial alinement with the axis of the cylinder l9. slidably mounted in the cylinder 19 is a piston head 2| from which a piston rod 22 extends in the direction of the adjacent surface of the hull Ill. The rod 22' is slidably mounted in a spider bearing 23 disposed within the cylinder, while a spring 24 surrounds the rod and is interposed between the bearing 23" and piston head 2| to normally urge the piston inwardly and hold the free end of the rod in close spaced relation to the hull II]. A stop'collar on the rod 22 limits the inward movement of the piston by its engagement with the bearing 23. The piston head 2| normally overlies bleed openings 25 provided adjacent the inner end of the cylinder l9. From the description thus far, it will be understood, that any fluid pressure force greater than the tension force of the spring 24 upon the piston head 21 from within the casing ll will cause the piston to move outwardly at which time the free end of the piston rod will impart a'striking blow to the hull l0. From the description to follow, I control the intermittent striking impacts of the piston by the human-voice frequencies to reproduce like voice frequencies using the hull as a vibratory diaphragm so that the amplified voice may be clearly-heard throughout a ship.
Fixedly mounted-within the casing l1 and extending the length and height thereof is a valve shutter plate 26 having spaced vertical air slots 21 therein; Slidably mounted along one side of the plate 26 is a shutter valve plate 28 which is provided with vertical slots 29 corresponding in number and spaced relation to the slots 21 in the plate 26. The plate 28 is provided with horizontal slots 36 through which pins 3| extending from the plate 26 pass. The length of the slots 39 predeterminably limit the range of sliding movement of the plate 28 in opposite directions. A contractile spring 32 has one of its ends fastened to the casing I7 and its other end connected to one end of the plate'28 to normally hold the slide plate at the limit of its sliding movement in one direction at which time the slots 29 are out of register with the slots 21.
One end of the plate is provided with an extending arm 32 which slides through one end wall of the casing l7 and to which the sliding core 33 of a fixedly supported horizontally disposed solenoid 34 is connected. Energization of the solenoid 34 imparts a sliding movement to the slide shutter plate 28 against the action of the spring 32 to position the slots 29 in register with the slots 2'! and by intermittently energizing the same by voice frequencies; the slide shutter plate will reciprocate and control the passage of fluid pressure from the branch fluid pressure pipe I to the cylinder I5.
Located at any suitable place upon a ship is a microphone 35 operatively connected by wires 36 to a conventional electronic audio amplifier unit shown diagrammatically at 3! and which includes a hand operated switch 38 for turning the same on and off. The amplifier unit receives its current from an electric supply circuit 38. Operatively connected to the output of the amplifier unit is an amplifier circuit 40 in which all of the solenoids 34 are arranged in parallel, thus the solenoids are responsive to the voice frequencies set up in the amplifier circuit in the same manner as electrically controlled element of a dynamic loud speaker. Thus the voice frequencies in the amplifier circuit control the actuation of the slide shutter plate 28 to admit the head of fluid pressure to intermittently act on the piston head 2! to cause the piston rod to forcibly strike the ships hull 15 to set up thereover a mechanical vibration at the voice frequencies corresponding to those entering the microphone 35. As the piston head 2! of each impact striker unit moves outwardly clear of the bleed openings 25 the air pressure acting upon the piston head is reduced causing the spring 23 to return the piston to its normal position, thus during operation of the ap paratus the piston will impart rapid intermittent taps to the ships hull to audibly reproduce throughout the ship, the voice sounds spoken into the microphone 35.
It is a known fact that the character of complex speech sound depends upon all overtones or harmonics and in this system of sound reproduction, there may be a distortion of the wave form between that entering the system and that set up by the hull of the ship, but not to the extent of complete loss of intelligibi1ity.. The pressure of air acting upon the striker piston varies as does the release of the pressure on the piston due to the actuation of the gate valve, thus the piston strikes the resilient hull and remains in contact therewith during its yielding vibratory movement at various degrees of pressure, thus making it possible to obtain overtones or harmonics necessary to intelligibly reproduce speech sound at like frequency, although the harmonics of the sound reproduced may vary from the harmonics of the speech sound entering the system.
To relieve the fluid pressure upon each impact striker unit l6 when the system is turned off at the switch 38, I provide electrically controlled shut off valves 4| in each branch pipe l5. Each valve 4| includes a normally closed valve element 42 movable to an open position by the energization of a solenoid 43, the sliding core 44 of which is connected to the valve element 42. The solenoids 43 of the shut off valves 4! are arranged in parallel within a circuit 45, the said circuit 45 being operatively connected to the current supply circuit 39 through the switch 38, so that when the switch 38 is ofi the circuit 45 is open and when the switch 38 is on the circuit 15 is closed and the solenoids 43 energized to open the valves 4| to enable the stored head of fluid pressure to enter the inlet side of the casings H.
In Figure 6 of the drawing, I have illustrated a slightly modified form of impact striker unit wherein l9 designates the cylinder communicating with the pressure outlet side of a casing I8. Slidable in the cylinder i9 is a piston head 2| having spaced longitudinal grooves 25 in the outside thereof. A piston rod 22 extends outwardly from the head 21 and is welded or otherwise secured to the ships hull 55' as at 46, The operation of the modified form of impact unit is the same as that previously described but the sound vibrations are directly imparted to the hull. The grooves 25' permit of the escape of fluid pressure but not such an amount as would efl'ect actuation of the piston when the shutter valve is in open position.
While I have shown and described what I con sider to be the most practical embodiment of my invention, 1' wish it to be understood that such changes and alterations as come within the scope of the appended claims may be resorted to if desired.
Having thus described the invention, what I claim as new and desire to secure by Letters Patent of the United States, is:
1. In combination with the metal hull of a ship, sound transmission means within the ship, and fluid pressure actuated striker means responsive to the sound frequencies entering said sound transmission means for imparting vibrations to said hull for reproduction of sound through the area thereof at like frequencies as that entering said sound transmission means.
2. In combination with the metal hull of a ship, voice transmission means within the ship, and fluid pressure actuated striker means responsive to the voice frequencies entering said sound trans mitting means for setting up vibrations of said hull at like voice frequencies to audibly reproduce sound to be heard throughout the ship.
3. In combination with the hull of a ship, an electric sound transmission circuit including an electronic amplifier, and a voice transmitter adapted to be suitably located within said ship, fluid pressure actuated striker devices for imparting vibrations to said ships hull, and means in said circuit responsive to the voice frequencies entering the same for controlling the actuation of said fluid pressure actuating devices to cause the same to act upon said hull to vibrate the same and reproduce sound throughout said hull at frequencies similar to the voice frequencies entering said voice transmitter.
4. In combination with the hull of a. ship, a voice transmission circuit having a microphone and an electronic amplifier arranged therein, and fluid pressure actuated striker means responsive to the voice frequencies passingthrough said circuit for imparting vibrations to said hull to reproduce sound of a frequency corresponding to the voice frequency entering said circuit.
5. In combination with the hull of a ship, a voice transmission circuit having a micro-phone and an electronic amplifier arranged therein, a plurality of impact striker units mounted relative to the null for intermittent striking contact therewith, fluid pressure means for actuating said impact striker units, and means responsive to the voice frequencies passing through said circuit for controlling the fluid pressure means to cause said impact striker devices to impart vibration to said hull to reproduce sound of a frequency corresponding to the voice frequency entering said circuit.
6. In combination With the metal hull of a ship, a voice transmission circuit having a microphone and an electronic amplifier arranged therein, an impact striker unit mounted relative to said hull comprising a cylinder, a striker piston slidably mounted in said cylinder, spring actuated means tending to hold said striker piston out of contact with the hull, pneumatic means connected with said cylinder for actuating the same to cause said piston to strike said hull, valve means for regulating the operation of said pneumatic means, and means in said transmission circuit responsive to the voice frequencies entering the same for imparting intermittent actuation to said valve means to intermittently actuate said striker pis ton to vibrate said hull at corresponding voice frequencies.
7. In combination with the metal hull of a ship, a voice transmission circuit having a microphone and an electronic amplifier arranged therein, an impact striker unit mounted relative to said hull comprising a cylinder, a striker piston slidably mounted in said cylinder, spring actuated means tending to hold said piston in a normally retracted position away from said hull, a pipe line,
a chamber connected to one end of said pipe line and communicating with said cylinder, means for maintaining a head of fluid pressure Within said pipe line, a slide valve arranged Within said chamber for regulating the flow of fluid pressure to said cylinder, and electro-magnetic means in said circuit responsive to the VOiCe frequencies passing through said circuit for imparting intermittent sliding movement to said slide valve, substantially as and for the purpose specified.
8. In combination with the metal hull of a ship, a. voice transmission circuit having a microphone and an electronic amplifier arranged therein, an impact striker unit mounted relative to said hull comprising a cylinder, a striker piston slidably mounted in said cylinder, spring actuated means tending to hold said piston in a normally retracted position away from said hull, a pipe line, a chamber connected to one end of said pipe line and communicating with said cylinder, means for maintaining a head of fluid pressure within said pipe line, a slide valve arranged within said chamber for regulating the flow of fluid pressure to said cylinder, and electro magnetic means in said circuit responsive to the voice frequencies passing through said circuit for imparting intermittent sliding movement to said slide valve, an electro magnetic valve arranged in said pipe line, an actuating circuit therefor, and switch means common to said amplifier circuit and to said actuat-