US2753006A

US2753006A - Blade wheel propeller

Info

Publication number: US2753006A
Application number: US327740A
Authority: US
Inventors: Gunther E Franz
Original assignee: Maschinenfabrik JM Voith GmbH
Current assignee: Maschinenfabrik JM Voith GmbH
Priority date: 1951-12-31
Filing date: 1952-12-24
Publication date: 1956-07-03
Anticipated expiration: 1973-07-03

Description

July 3, 1956 G. E. FRANZ 2,753,006

BLADE WHEEL PEOPE EER Filed Dec. 24, 1952 INVENT OR Giizil her E Fran;

BLADE WHEEL PROPELLER Gunther E. Franz, Heidenheim (Brenz), Germany, as-

signor to J. M. Voith G. in. b. H., Maschinenfabrik, Heidenheim (Brenz), Germany Application December 24, 1952, Serial No. 327,740

lairns priority, application Germany December 31, 1951 3 Claims. (Cl. 170-151) The present invention relates to ship propellers and, more particularly, to blade wheel propellers. As is well known, the blades of blade wheel propellers-cycloidal propellers-are during their rotation about the propeller axis controlled according to certain laws by a blade drive mechanism, mostly called kinematics. While in operation, the blades carry out an oscillating movement about their tangential position, the amplitude of which may be influenced by the speed lever or speed stick whereas the phase of said oscillating movement can be influenced by the steering wheel.

As blade drive mechanism for high speed cycloidal propellers, the socalled connecting rod kinematics have proved successful. With this construction, also called sliding link kinematics, the blades are coupled by means of a blade lever, a connecting rod, and a slide rod with annular control center which in the zero position of said blades is located centrally and which is rotatably connected with the propeller in any convenient manner. The said slide rod is guided in a slide member-cross headwhich is rotatably journalled in the propeller wheel.

In addition to the above, also a number of further kinematics have been suggested. As far as they have been built, they have at least in part proved successful as to design. However, they could not get adopted by the ship building industry over the materially simpler connecting rod kinematics. On the other hand, even with the proven connecting rod kinematics, the blade wheel propeller has not been adopted to the extent it would deserve in view of its excellent maneuverability and its simple operation. This is due primarily to the fact that is materially higher in price than the screw propeller drive.

in an effort to develop a kinematics as simple and as low in cost as possible, already two decades ago, the construction of a simple sine-kinematics has been suggested and discussed. Preliminary research tests, however, have yielded so poor a degree of efliciency of sine-kinematics that experts in this art have abstained from further tests and have dismissed the sine-kinematics as completely impractical. Also, in the meantime occasionally advanced suggestions concerning the sine-kinematics have produced no success inasmuch as these suggestions were expected merely to confirm the results of the above mentioned research tests.

More recently it was believed that an explanation of the impracticability of the sine-kinematics had been found. It had been found that with a blade wheel propeller a great angle of attack or blade angle can be selected without having to fear that a separation of the how or cavitation will occur. However, it was believed that a sinusoidal blade angle graph in the first range of the front wheel half-ascending branch of the sine curve and in, the oppositely located last range of the rear wheel hnlfdescending branch of the sine graph-wou1d automatically cause too fast a rise or drop of the approach flow angle and thus would produce cavitations and losses in efficiency. This explanation further strengthened the ICE heretofore prevailing opinion concerning the impracticability of the sine-kinematics.

It is, therefore, an object of the present invention to provide a blade wheel cycloidal propeller with sinekinematics which will overcome the above mentioned drawbacks.

It is another object of this invention so to simplify the sine-kinematics for use in connection with blade wheel cycloidal propellers that such a construction will not only be able to compete with screw propellers but will have distinct advantages over the latter in connection with certain types of ships or vessels.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings in which:

Fig. 1 diagrammatically illustrates a cross section through a propeller according to the invention.

Fig. 2 represents a top view of the blade drive linkage.

Fig. 3 is a graph concerning the blade angle in connection with the propeller according to the present invention.

General arrangement Recent tests have revealed that the heretofore prevailing opinions concerning the sine-kinematics with blade wheel cycloidal propellers represent an unjustified prejudice, and that with sine-kinematics very favorable results can be obtained provided that the blade wheel driving mechanism yields a sinusoidal blade angle graph which for all practical purposes is the same for each and every blade of the same blade wheel. The blade angle epsilon plotted over the circumferential angle phi, should therefore, yield a sine curve, and this sine curve should for each blade of one and the same blade wheel be practically the same and equal the sine of the circumferential angle phi. This condition is met by a blade wheel propeller according to the invention which is characterized in that the inner end of each coupling or connecting rod of one and the same blade wheel ends in an annular member or portion and that all of said annular members or portions are superimposed upon each other and are arranged concentrically with regard to each other and with regard to the lower end portion of the control member regardless of the control position of said control member. According to a specific embodiment of the invention the control member is designed as control stick having a lower ball shaped end. This ball shaped end forms the control center and has pivotally connected thereto the inner ends of all coupling rods which in their turn are connected to the blade levers. The arrangement is such that the respective longitudinal axis of each of said connecting rod means intersects the axis of said control means in all positions of said control means whereby substan-.

tially the same sinusoidal blade angle curve is obtained for each of said blades.

Structural arrangement Referring now to the drawings in detail and Fig. 1 thereof in particular, the arrangement shown therein comprises a hollow shaft 1 through the intervention of which the wheel 2 of the propeller is rotated. The wheel 2 is in a manner known per se carried by a part 3 which extends into the hollow shaft 1 and pertains to a stationary casing (not shown in the drawing). The

blade

4', 4 and 4 are rotatably journalled in the wheel 2. Respectively slipped over the

blade pivots

5, 5, 5 are

blade levers

6, 6, 6" having pivotally connected thereto at 100, 100" coupling or connecting

rods

7, 7a and 7b respectively. The inner end of each of said

coupling rods

7, 7a, 7b ends in an annular portion 7', 7a, and 7b,

respectively. Said annular portions are arranged concen-. trically with regard to each other and concentrically ex" tend around the ball box 9 at the lower ball-shaped end 10'1'1 of the 'cont'rofsticklfl "will be elearrrsn the drawings, the

coupling rods

7, 7a, 7b are arranged at d erent le lsl sete ab v a o her- T e ner end 75"'orthsintrmeainecou ling semis d' (1 g bushin qt a height which equals'the dis an between tie up er surface of annular portion '7' and the bottom Q 111 .113; portion'lb. It will also be noted from the"drawing'that the annular portion 7a includes, an annular section '7. separating the annular portions 7.-' and 'Z'bj. fforn" "Chothe'r'." Furthermorefthe annular portions of? the coupling rods areslidably mounted'between the, upper an I1, of the wheel 2 and an intermediate wan 12. For, purposes" or simplification or the drawing, Fig 1 shows the two "blades 4" and 471 f Fig. 2 as if theywere szcatedint e amepl eho'wsf'thetwo blades with their control system n for, speed ahead'the traveling direction inap' anigindica'tea b ihe'arrow 13; AS will be" seen rom Fig, 2,, also when the center of ball 10;: by actuatioii or stick 10 has been moved in o an eccentric position with regard to the fort the circle on which the tilting. axes b and 41" are located, the center of 11 ltlfand the center of the annular portions 7,

7a" and '7b"still remain located on one and the same line.

This may also be expressed in a different way namely e ard es of e cont ol pos tion of h control sti k rash-en eri g 7",7a arid Vb" pass through the same lih'e whichfin Fig, 2 is represented as an intersecting point or the projection of the axes 7 7a" and 7b".

3 'shov' vs th'e blade angle epsilon plotted over the H ferential angle phi and also shows the sine graph obtained thereby. This sine graph is the same for'each andall'o'f theblad es 4 4," and4'.

Tests carried outwith a propeller having a sine kinemataccording to the present invention have proved that suchia propeller is particularly advantageous when used as a 'p 'opeller with a medium or high loading factor, in other as propeller for slowly. travelling, relatively heavy rich as tug boats, floating cranes, or the like. 'purp'oses,"the blade wheel. pt peller'according e sent invention may be further simplified by reg uci g the numberjof blades as far as possible so that the, I a i bpd PlYT iP h e Wid bl de It h been found that small number of blades is particu l ly 'a drnissible for slowly running propellers whereas,

Ablfadewheel propeller according to thepre ent invention is therefio're fundamentally simpler than any. other known" desi'gnsf'The blade drive rod system for each ic m t ling rod which, is centrally pivotally connected,- toa eope'rable by the, control stick 10, The. blade '6 and the; coupling rods, 7, 7a and 7b, with, the exception of their inner annular portions" may respec: tively all be of the same design. Furthermore, a carrier device for the control center for a synchronous or isochronous, carryingalong of the, control center by means of th e wheelbodyis' superfluous according to the pre se nt.

invention, The, factor thatonlythrceblades are required for a reliable operation ofv the propeller, materially contributes toa: simplification and-a reduction in. costof the It, is, ofjcourse, understood, thatthe present invention. r ng, means, imi d e, r c larn ruc ion.

s in addition to the blade lever onl'y one controlfpivot which may in a manner known shown in the drawings but also comprises any modificatrans "wnaiameseo'pssr the appended claims.

What I claim is:

1. In a blade wheel ship propeller arrangement having a rotatable wheel with a plurality of blades respectively provided with shafts operable to oscillate said blades about the respective axes of said shafts, the combination of: a plurality or blade lever means respectively connec ed t said shafts pluralit of nect n o means. having their, outer efuds respectively. pivotally connected to said blade lever means, the'inner. ends of said connecting rod means being formed with annular portions arranged concentrically with regard to each other and superimposed upon each omen, and c n rol me ns 011- centrically surrounded by said annular portions and operable selectively to'shift the said annular portions from a position concentric to said rotatable wheel into a plurality of positions eccentric thereto and vice versa, the respective longitudinal axisof each. of said, connecting rod means intersecting the axis of said control means in all positions ot's'aid control means whereby substantially the same sinusoidal blade angle'curve is obtained for each of said bladesj In a blade, wheel ship propeller arrangement which includes a rotatable; wheel 'with oppositely located spaced central wall sections extending substantially perpendicular to the axis of rotation of said wheel, and, in which said rotatable wheel carries a plurality of blades respectively provided with shafts operable, to oscillate said blades about the respective axes of said shafts, the combination of: a plurality of. blade lever means respectively connected to said shafts, a; plurality of connecting rod means having their. outer endsv respectively pivotally connected to said blade. lever. means, the inner ends of said connecting' rod means being. formed with. annular fiat portions concentrically arranged with regard to. each other and superimposed upon, each other, said annular portions being journalled between. said; oppositely located spaced central wall sections of said wheel so as to allow oscillation 'of said annular portionsrela tive. to each. other, ball bo'imeans mounted within said. annular'fportions, and control stick' means including a. ball-shaped portion jourhalled, in said ball box means and operable selectively to shift said annular. portions from a position concentric to said rotatableiwheel into a plurality of positions efccehtrici'the reto andvic'e versa, the respective longitudinal arises eacho' fl said connecting rod means intersecting the. axis of said control. rneansfin, all positions of said control. means whereby, substantially the same sinusoidal blade angle curve is obtained for each of said blades.

3. In a bladewheel ship propeller. arrangement having a rotatable wheel withan uneven number of blades respectivelyprovided with shafts operable to oscillate said bladesabout therespective axes of said shafts, the combination of: a plurality of blade lever means correspondingjn number .to that'of said'blades andrespectively connected; to said; shafts, a plurality ofconnecting rod means, corresponding in number to that of said blades and having, theirouten ends respectively pivotally connected tosaidblade levermeans, theinnerfendsof'said connectingrod meansflbeingiformed with annular portions concentrically arranged with regard to each other and superimposedupon each, other, said. annular portions being supportedbysaid. wheel and being oscillatable relative theretoand relative to eachiotherfthat, annular portion which hasthensamernumber oft-annular. portions arranged above and, below thereof; having integral therewith a sleeve, concentrically located within said. other annular portions, and control, means concentrically surrounded bysaidannular.portions and operable selectively to shift.

all -ofsaid annular portions asaunit frornaposition concentric to said .rotatablewheel intoa plurality of positions eccentric thereto and: vice .versa, the respective longitudinal-,axisof each. ofrsaidrconnectingl rodimeans intersectng,thea iis ofssfldacontrol:rneans. in.all-.positions .oflsaid 5 control means whereby substantially the same sinusoidal 2,250,772 blade angle curve is obtained for each of said blades. 2,580,428

References Cited in the file of this patent UNITED STATES PATENTS 5 2,037,069 Ehrhart Apr. 14, 1936 1313:7117

6 Mueller et a1 July 29, 1941 Heuver Jan. 1, 1952 FOREIGN PATENTS Germany June 15, 1951 Germany Nov. 29, 1951 France Aug. 4, 1952