US1482381A - Propulsion mechanism - Google Patents

Description

Feb. 5; 1924. 1,4823@ H. M. CAKE PROPULS ION MECHANI SM Filed July 6, 1918 5] wom/Hofe Patented Feb. 5, 1924.

f NITE!) srA'rs HORACE M. CAKE, 0F PHILADELPHIA, PEN'NSYII'ATANIA.

PBOPULSION Application led July .6, v

To all whom t may concern.

Be it known that I, HORACE M. CAKE, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Propulsion Mechanism, of which the following is a specification.

This invention relates broadly to propulsion and more specifically to mechanism for balancing and stabilizing propelling systems.

The principal object of the present invention is a mechanism for propelling torpedoes, airships, and the like, by rotary screw propellers driven in such manner as to overcome any tendency of the propeller action to cause the torpedo, airship, or the like, to rotate on the axis of the propeller.

A still further object of the present invention is a mechanism as specified wherein the invention is characterized by rotating a pair of screw propellers in opposite directions and com ensating the forces absorbed by the propel ers in such manner that each propeller at all times absorbs one-half of the drivin power.

A still urther object of the present invention isa mechanism as specified and wherein the forces to be absorbed by the propellers are delivered through compensating mechanism which transmits the energy directly to one propeller-and through reversing gearin to the other propeller, whereby the propel ers are driven in opposite directions through the compensating devices so thatfvibrations due 'to the passing of propeller blades ongpposingpropellers are not4 ytransmitted directly to`thedriving shaft but `are absorbed through'thefunctioning ofthe compensating mechanismand'by means of the framework. 'j f p More lspeciiicallylone .mechanism for carrying outpmy'invention comprises ahead,

ldirectly connected tothedriving or` povv'er shaft, and carrying compensating. gears.`

One sideof these gears'pis4 directly (':onnectedto al bevel gear on thepropeller shaft for the outer propeller, and theother-iside'"there-l of isconne'cted with1 a bevelfgez'urwhichv transmitsthrough a lcasing to reversing" gears which vdrive a tubular shaft carrying" the inner propellerpsothatthe 'entire 'sys- 'f tem comprisesa pair of voppfositely ydriveny propellers rotating on a common axis and MECHANISM.

1918. Serial No. 243,523.

receiving power through a differential compensating gearing. Other and further objects of the present invention will in part be obvious and will 1n part be pointed out hereinafter in the specification following by reference to the accompanying drawings Aforming a part thereof. y

The figure of the drawing is more or less diagrammatic and shows a portion of the construction in section in order to more clearly illustrate the relation of parts.

In the art of screw propellers it is well recognized there is a tendency of a single screw propelled ship, torpedo, aeroplane, or

the like, to rotate on the axis of the propeller shaft and oppositel to the rotation of the propeller itself. This ei'l'ect is partly due to reaction on the propeller blades, partly due to the impossibility of making theoretically true propellers for all conditions of speed, and partly due to other causes well known in the art. Attempts have vbeen made to overcome the foregoing difficulties by using twin screws rotating on independent axes; and also attempts have been made to. eliminate the foregolng diiculties by providin a pair of oppositely rotated positively riven screws revolving about a common axis. The latter mechanism is most commonly employed for propellers for torpedoes. Neither of the proposed constructions completely overcome the difficulties specified vand in both cases additional vibration is introduced. In propellers rotating in opposite directions around a common axis,"vibration is accentuated because each timethe blades on one ropeller pass into the zone of waterdisturbe 'by the blades of the other propeller, a different stress conditionis established, and where the propellers revolve vat high speedthe vibration due 'to ythis conditionl is greatly increased,V

y"and absorbs a large am'ountof tlie driving ener .y "Furthermore because of the imposn sibilityy'of ymaking theoretically correct propellerspas'to pitch,lbalance, etc., it is difi vficultfandvi-n practicfefis substantially impos- "siblefto provide af pair'of positivelyvdriven propellers vwhich will not rotate the body of a torpe. v-being driven V.through the water.

nating vibrations due to propeller designs,

io' dolaround its own, axis whenit is i To oveicometlie'diiiiciilties o f the-knownk fartaiid to provide aconstruction lfor elimiy. lll() I lsis and water or air disturbances, theinvenvtionA which will more specifically be described hereinafter, comprises broadl the arran ement of a pair of axially aligned prope 1ers of opposite pitch mounted in such manner as to receive their driving power through a differential gearing an reversing gearing so that one-half of the horsepower of the driving forces rotates one screw propeller in one direction and the other half of the driving power rotates the other screw propeller in the opposite direction. By this construction it will be noted that when any unbalanced condition exists as to one propeller the surplus force producing the unbalanced condition is transmitted immediately through the differentialgearing to the other propeller so that at all times there is true compensation between the propellers without transmitting the compensatory forces or stresses to the drivin shaft. This fact tends to relieve the driving shaft of forces which otherwisewould cause undesirable vibration. It will also be noted 4that by this construction if there is a tendency of the torque of either propeller to preponderate over the other propeller in such manner as would cause'a torpedo, or the like, to rotate on its own axis where the propeller is positively driven without reciprocal action, such preponderance is immediatel. absorbed by being distributed between t e propellers. Therefore there is no turning element or function which tends to rotate the boat, torpedo, airship, or the like, around the axis of the propeller shaft, where this invention` is used.

Referring now more particularly to the drawings the drive shaft 1 carries a transmission head 2 on which is mounted a pair of compensating gears 3. The compensatingx gears on one side engage a bevel gear 4 t at is integral with a collar 5 that is free lto rotate around the drive shaft 1. This J collar 5 carrying the bevel ear 4 is secured to a housing 6, b means o machine screws or the like. This housing terminates in a reversing bevel gear 7 which engages one side of a pair of idler gears 8 mounted to rotate on stubshafts 9 that are anchored in the stationary member 10 which is secured to a part of the frame work 11 of the torpedo, ship, or 'other construction, carrying this propelling mechanism. The compensatin gears 3 are also in engagement with a beve gear 12v which is secured to a propeller shaft 13. The idler gears 8 also engage a bevel ar 14 which is mounted on a tubular prope er shaft 15 adapted to rotate about the propeller shaft 13. The tubular propeller shaft 15 carries a propeller 16 having its blades pitched in one direction and the propeller shaft 13 carries a ropeller 17 having its blades pitched in t e opposite direction.

It is obvious from the foregoing that power from the driving shaft 1 will` be transmittedy equally to the propellers ,16 and 17 one half of the power going to each propel er. In view of this fact it is also obvious that the resistance on these propellers tends to be equal'at all times. Now since the pitch of the blades on propeller 16 is opposite toI the pitch of the blades on propeller 17, and since the propellers rotate in opposite directions it follows the driving reactions on the propellers are equal and opposite so that the system is rotatively balanced on the axis around which the ropellers revolve. Furthermore since the alancing of the otherwise unequal conditions is, accomplished by energy transference from one propeller to the other, the main driving shaft is relieved from stresses that would otherwise dissipate a portion of the driving energy. This results in a balanced cushioning action which renders the reaction-against the main driving shaft smooth and even and is a further reason for obviating shocks and vibrations as previously specified. i A

It is obvious that the specific constructions herein disclosed. ma be varied somewhat without departing rom my invention and therefore I desire that it shall be understood that the disclosure herewith is i1- lustrative and not to be taken in the limitin sense.

aving thus described my invention what I claim is:

1. In a propulsion mechanism in combination, a drivin shaft, a transmission head carried on sai driving shaft, compensating gears upon said transmission head, a face plate carrying thereon a beveled gear in engagement with the compensating gears a tubular shaft, a propeller on said tubu ar shaft, a casing secured to said face plate. reversing gearing operatively connecting said casing and said tubular shaft, a cylindrical shaft mounted within said tubular shaft, a propellercarried upon said cylindrical shaft, and a beveled. gear on the cylindrical shaft and in engagement with the compensating gears; the driving shaft, the

tubular shaft, and the cylindrical shaft, all y v being in axial alignment.

2. In a propulsion mechanism in comblnation, a driving shaft, a transmission head, compensating gears carried by said transmission head, a cylindrical shaft, al tubular. driven shaft, operative means connecting said tubular shaft with said compensating gears, said operative means includin versinggearing connecting said cylin rical shaft with said compensating gears to drive IIS said cylindrical shaft in the opposite rotay tive direction to which said tubular shaft is driven, a propeller carried upon said tubular shaft and a propeller carried upon said cy`- lindrical shaft; the driving shaft, the tubi1- lar shaft and the cylindricali driven shaft all i being in axial alinement.

3. In a propulsion mechanism in combination, a driving shaft, a transmissiony head carried by said driving shaft, compensating gears carried on the transmission head, beveled gears engaging said compensating gears on d1ametrical y opposite sides, a tubular shaft, a propeller on said tubular shaft, reversinggearlng, a cylindrical shaft mounted Within said tubular shaft, apropeller carried on said cylindrical shaft, one 'of said beveled gears being operatively connected with said tubular shaft through said reversing gearing, and the other of said beveled gears being operatively connected With said cylindrical shaft; the driving shaft,

the tubular shaft and the driven cylindrical shaft all being axially alined.

4. In a propulsion mechanism in combination, .a driving shaft, two driven shafts. screw propellers carried on said driven shafts, reversing gearing, and com ensating means operatively connecting sai driving shaft with one of said driven shafts independently of said reversing gearing and op eratively connecting said driving shaft through said reversing gearing to the other driven shaft to drive the driven shafts in opposite directions, the blades of the screw propellers being pitched in opposite directions; the drivlng shaft and both driven shafts being in axial alinement.

HORACE M.y CAKE.

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