US2336256A - Propeller spinner - Google Patents

Description

Dec. 7, 1943. H. e. JUNGER PROPELLER SPINNER Filed Jan.- 1 1942 4 Sheets-Sheet l INVENTOR. f/zwev G. JUNGEIQ ATTORNEY Dec. 7, 1943. H. G. JUNGER PROPELLER SPINNER File d Jan. 1, 1942 4 Shets-Sheet 2 INVENTOR. G. (/UNGE/E HEMP Y BY Mm 5F A TTORNEY Dec. 7, 1943. H. e. JUNGER PROP ELLER SPINNER Filed Jan. 1 1942 4 Sheets-Sheet 3 INVENTOR.

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2.; 6 no 55 7 O I wd a a .9 F m m 2 A TTORNEY Dec. 7, 1943.

H. G. JUNG ER PROPELLER SPINNER Filed Jan. 1 1942 4 Sheets-Sheet 4 INVENTOR. ///v/? l/U/VGEE. Ila/m5. (Illa/ ATTORNEY Patented Dec. 7, 1943 PROPELLER SPINNER 1 Henry G. Junger, Dumont, N. J., assignor to Air Associates Incorporated, Bendix, N. J.,

poration of New York Application January 1, 1942, Serial No. 425,254

3 Claims.

The present invention relates to a spinner for an aircraft propeller. In spinners of the type here under consideration, it is imperative that the entire outer surface is evenly curved and that no projections or other interruptions of its smooth skin disturb the uniform flow of the air current along the surface in flight. For this reason, the means for securing the spinner of conventional type to a propeller hub are arranged in its interior with the effect that these means are accessible only from the rear of the propeller.- In consequence thereof, particularly in constant speed-full feathering propellers which require frequent inspection of the control mechanism arranged in front of the hub, it is a cumbersome and time wasting job to remove and to restore the spinner for that purpose because of the limited space in the rear of the propeller and of the necessity of removing other parts, such as the motor cowl, in order to provide access to the parts inclosed by the front portion of the spinner.

The invention contemplates the provision of a spinner whose front part at least can be removed from or attached to the propeller hub from the front side without sacrificing the smoothness of the surface or any other required quality of an efiicient spinner. The invention further aims to provide a spinner of the mentioned type whose central front portion is free from impeding interior structure so as to be useful to encase an extraneous propeller control mechanism or other device. The invention consists of a spinner comprising a bipartite shell, the rear part of which can be slipped over and secured to the hub from the rear; whereas the front part can be secured to or removed from the other part by working from the front side. The invention further comprises the provision of a trap door mechanism for openings in the front removable shell through which tools may beapplied to the means connecting the two parts to each other. The invention also comprises a removable partition or bulkhead stifiening the front end of the rear shell and holding it concentric with the propeller hub center line.

Further details and objects of the invention will be apparent from the description given hereinafter and the accompanying drawings illustrating an embodiment thereof by way of invention.

In the drawings:

Fig. 1 is a longitudinal section of a spinner according to my invention;

Fig. 2 is a rear elevation thereof, parts of the shellsbeing broken away; 3 is a sectional view of a portion of the spinner showing the connection of the bulkhead to the rear shell on a larger scale;

Fig. 4 is a similar view of the connection of the two shell parts and of a trap door;

Fig. 5 is a top plan View of the trap door of Fig. 4;

Fig. 6 is a section along line 66 of Fig. 5;

Fig. 7 shows a modification of the parts illustrated in Fig. 4, and

Fig. 8 shows a cross-section along lines 8+8 in Fig.7.

Referring now to the figures, It indicates a propeller hub to which a spinner according to my inventionmay be applied, and II denotes a diagrammatically illustrated controlling mechanism for the blade adjustment, which mechanism is attached to the front of the hub Ill. A rear flange I2 and a front flange I3 are integral parts of the propeller hub. The spinner comprises a front shell I4 and a rear shell I5 of sheet metal, e. g. an aluminum alloy, so shaped as to form the front portion of a substantially streamlined body whose rear portion may be constituted by an adjacent part (not shown) of an airplane to which the spinner may be applied. Means are provided to stiffen this shell and to attach it to the propeller hub II] when slipped over the latter from the rear. For this purpose, the shell I5 has a bottom IS with a peripheral flange IS fitting into the shell I5 and secured thereto by means which do not cause a projection on the outer surface, e. g. by spot-welding or flush-riveting. Bottom I6 has a central opening I1 and a number of bolt holes I8 in registry with corresponding holes in flange I2 for the attachment of the bottom I6 thereto by means of the bolts and nuts I9. The front end of the shell I5 is vcircumferentially set 01f or restricted at 20 and bent inward so as to iorm a In order to permit shell I5 to be slipped over the hub I0, recesses 40 are provided, as many as there are propeller blades 4|, i. c. three in the illustrated embodiment. The recesses extend from the front end of the shell and are so shaped that the blades 4| can pass therethrough as far as required for theattachment of bottom I6 to flange I2. A stiffener 42 of angular cross-section is securedall along the rim of each recess on the inside of the shell by means indicated at 43. The front ends 44 of the stiffener are bent off parallel vto the flange 2| and secured thereto in combination with other parts as will be explained hereinafter. The portion of each recess 40 not occupied by the pertaining blade when the spinner is attached to the hub can be closed by a lid 45 with nuts 25. The ring 22 has a cylindrical. rim" 26 whose outer surface constitutes the seat for slidable engagement of the bulkhead 2'! which will be described hereinafter. However, it will be clear that ring 22 is a unit separate from hub I!) only for reasons of manufacture and that for the purpose of the present invention the cylindrical face provided by the ring portion 26 may be a face of the hub proper. The bulkhead 2'! of the illustrated embodiment comprisesa sheet metal body having a main portion 28 of conical shape, a plane outer flange 29, a cylindrical inner end 30, and a lining 31 of' an elastic material, such as synthetic rubber, secured to the inner surface of the cylindrical end 30 by any suitable means such as rivets 31'. The dimensions are so selected that the bulkhead can be shifted in axial direction from the front side of the hub on the cylindrical portion 26 of mounting ring-'22 whereby the elastic lining will be somewhat compressed. In. assembled position flange 29 of the bulkhead is in front of and slightly spaced from the flangeZl of shell If) as clearly shown in Fig. 1. Instead of being secured tothe bulkhead the lining 31 may be fastened to the outer surface of the ring 122. However, the illustrated arrangement is preferred because it is easier in production to make the mounting ring fit the hub and the bulkhead than to make the bulkhead fit the mounting ring.

The rear end of the front shell I4 is provided with'an internal flange 3! of L-shaped cross-section whose outer substantially conical portion .32 fitting the shell curvature is secured to the inside of the front shell I4 by suitable means such asspot-welding or flush-riveting (not shown); whereas the substantially plane portion 33 in the assembled spinner is located in frontv Of and slightly spaced from the bulkhead flange 29. The rear end of front shell M with the portion 32 of flangefil fits over the restricted end at 22 of the rear shell -I 5, and the parts are so shaped that the outer surface of the rear shell is the uninterrupted continuation of the outer surface of the front shell [4 except for the insignificant gap 3-4 which may occur where thetwo parts meet. The front end of the shell M may be provided with a central hole 35 closed by a removable cap 36 which is shown as made of rubber but may be made of any suitable material. It will be noticed that the bulkhead :2"! intermediate the two shells is funnel shaped rather than plane. This has been done in order to give this part greater stiffness and also to make the front shell shorter, i. :e. to make both shells more similar to each other in length than it would be possible with a plane bulkhead. The connection of the bulkhead to the rear shell 15 and of the'front shell to the rear shell in the illustrated embodiment is accomplished in the following manner. It has been stated hereinbefore that the end flanges l of the stiffeners 42 are secured tov the rear side of thesheill flange 2'! thereby six local reinforcements of the flange 2| are produced. These reinforced portions are utilized to anchor a stud aesaese bolt in each of them as is clearly shown in Fig. 3.. Each bolt has a flange head 5| and is passed from the rear side through a hole 52 in the reinforced portion. The head 5| is secured to that portion by rivets 53 or other suitable means. The rear portion of the shaft of the stud bolt is provided with longitudinal edges 54 forced into the wall of the hole 52 thereby contributing to the resistance of the bolt against undesired turning. The front end of the bolt is threaded at 55 so as to receive thereon a nut 56 bearing on the front end of a flanged tubular steel piece or ferrule 51 whose other end is flared into the rear face of a steel ring or washer 58 which is assembled on the rear side of 29, and the piece .51 is passed through a corresponding hole in flange 29 against whose front face piece 51 bears with its flange. A hole 60 is also provided in flange '33 in registry with the holes 52 and 59 and of sufficient size to permit the nut 56 to pass therethrough with ample clearance. In the illustrated embodiment six such bolts 59 are providedin accordance with the number of reinforcing ends of the stiffeners 42. However, it will be clear that no immediate connection need exist between thestiifeners and the bolt, and that-any other suitable number of bolts may be used because it is necessary only to anchor the bolts to the flange 2 4' and to secure thereto the bulkhead 21 when applied to the. bolts from the front end of the shell [5. 7

In a similar manner .a second set of anchor stud bolts 6! shown in Fig. 4 is used to secure the flange 33 of the front shell to the bulkhead flange 29 and the rear shell flange. 2|. .Each stud bolt 6| has a head 62 secured to the rear side of flange ,2l'. A ferrule 63 is provided whose flange safeguards thedesired spacing of. flange 2.9 from 2|; whereas another ferrule 64 of a shape similar to that of..the afore-mentioned ferrule 51 fittingly engages a hole 6 5 in flange 33. The pieces 63 andfi l abut against each other and a gasket ring or washer 66 is provided between flanges 29 and 33. Now it will be clear that nuts 61 on bolts 6| which are passed through the ferrules 63 and 64 will hold the front shell securely attached to the bulkhead and the rear shell !5. In theillustrated embodiment the set of bolts 6| is so arranged that circumferentially one bolt 6| follows two bolts 5!]. However, it will be. understood that other arrangements may be used in an equally satisfying manner. It is even possible to use only bolts GI and connections of the type illustrated in Fig. 4 because it is only necessary according to the spirit of the invention to secure the parts in consideration to each other from the front side of the propeller to which the spinner is applied.

In order to make the nuts 61 of the set of bolts 6.! accessible from the front of the propeller hub I provide trap doors in shell [4, one in front of each of the bolts so that a tool such asa wrench may be applied through the door opening for removing or fastening the nuts. Each trap door device '5 comprises a reinforcing plate 1| secured to the inner surface of shell I4 and having an opening 72 in registry with an opening of like size and shape in the shell proper. The opening is elongated according to the inclination of the portion of the shell curvature with respect to the axis of-the pertaining bolt 6| so that a tool 13 indicated by dash lines in Fig. 4 may be passed through the opening and stuck on the nut 61. The front end of plate H is formed as the stationary part 15 of a hinge. The trap door proper consists of a plate 16 with the movable hinge part 11 and upturned rims 18 and 19 on both longitudinal sides. A pivot rod 80 is passed through hinge parts 15 and 11. A filler 8| of the size of the opening 12 is riveted at 82 to the bottom of the trap door so that the surface of the spinner is uninterrupted when the trap doors are closed. It will be clear that a trap door of the type disclosed will always be closed owing to the centrifugal force when the spinner is rotating, and that it can be opened by pressure.

exerted from the outside against the filler 8|. In order to ensure closing of the trap door even if the spinner is standing still a spring 83 is wound about the pivot rod 80 at 84 and bears with a loop portion 85 against the top of the plate 16. The ends 86 and 81 of the spring 83 are held by a retainer 88 which is secured to the inside of the shell I4. Detent means are provided to hold the trap door open against the restraint of spring 83 while a tool such as 13 is applied to the pertaining nut 61. For this purpose, a portion of plate H is bent inwardly and upwardly inclined so as to form a tab-like projection 96, and a leaf A extension 93 is formed substantially triangular as best seen in Fig. 4 so that when the trap door is lifted rim 94 will come to rest on top of the end 95 of leaf spring 9| whereby the trap door is prevented from being shut. By reaching with a finger through the opening 12 one is able to push back the spring 9| whereupon the trap door will be shut by spring 83.

It will be seen that the minimum size of the trap door opening is so defined that its projection upon a plane perpendicular to the axis of the coordinate bolt is at least equal to the crosssection of the tool applied to the nut 61. In consequence thereof, it may happen in certain spinners where the curvature of the shell in an axial plane is very shallow that trap doors of very considerable size and tools of excessive length are required if the axes of the bolts 6| are parallel to the spinner axis. This difliculty can be overcome by a structure according to the modification shown in Figs. '7 and 8. In this structure the axis I ofbolt |6I is inclined and it will be clear that such inclination of axis ||l|| diverging as to its forward directed portion from the spinner axis (not shown) brings the trap door mechanism-only part of which is shown in the figure-closer to the connected flanges and simultaneously permits a trap door of smaller size than would be necessary if the axis I99 were parallel to the spinner axis. However, it will be likewise clear that the inclination of the bolt axis also calls for an inclination of the flange I 2| of the rear shell I I5, of flange I29 of bulkhead I21, and of flange I33 of the front shell I| which, consequently, are portions of co-axial cones having their apices on the spinner axis. This conical shape, however, prevents the use of bolts of the type 6! of Figs. 3 and 4. Therefore, in the modified structure, the headed bolts ISI are inserted from the front with their respective axes normal to the conical flange faces, and anchor nuts I61 which may be of conventional type and for this reason do not require further explanation are secured to the rear side of flange |2| by means of rivets I68. Furthermore, the faces of the anchor nut I61, of the ferrules I63 and lfid'and of the washer I66 which are in engagement with the surfaces of the flanges 2| I29 and I33 are curved according to their conical shape. Accordingly, the bolt connection of the bulkhead and the flange of the rear shell illustrated in Fig. 3 would have to be modified, as it will be understood without additional description in view of the foregoing.

The spinner according to the invention is assembled in the following manner: First, the shell I5 is slipped from the rear over the propeller hub with the blades 4| engaging in the recesses 39 and the bottom I6 is fixed to the hub flange I2 by means of bolts I9, the nuts of which can be reached from the front through the wide opening left by flange 2 I. When this is done, the remaining job of assembling the spinner can be accomplished by working from the front of the hub. The covers are inserted between the flanges 41 of the recess stiffeners 42 and secured by means of the screws 43. Then, the mounting ring 22 is bolted to flange I3. Now, the bulkhead 21 with washer 58 and ferrules. 59 and 63 in proper position can be inserted by shifting ring 31 on the cylindrical portion of 26 and by introducing the bolts 59 and 6| into the said ferrules. The tightening of nuts 56 completes the assembling of the rear shell I5. In order to assemble the front shell I4, the ferrules 64 and washers 66 are applied to the holes 65 of flange 33, and the shell I4 is then .put on the restricted portion at 2|! of shell I5 whereby the nuts 56 enter the holes and the threaded portions of the bolts 6| pass through the ferrules 64. Thereafter, the nuts 61 can be applied to bolts 6| and tightened with the aid of a tool introduced into the interior of the shell through the openings 12, When, finally, the trap doors 16 are closed by releasing the detent springs 9| the spinner assembly is completed. Hence, in order to remove and to restore the front shell I4 when inspection of the control mechanism II is required it is only necessary to turn the nuts 61 off and on by reaching through the trap door openings 12. No other part, especially no part in the rear of the propeller hub, need be manipulated for that purpose. Even the interior of the rear shell I5 is accessible from the front side after the removal of the bulkhead 21.

In the case of the modification according to Fig. 7 the sequence of operations is similar to that hereinbefore described with the difference only that bolts |6| are screwed into anchor nuts where in the first described case loose nuts are applied to anchored bolts.

It will be apparent to those skilled in the art that many alterations and modifications of the structure described and illustrated by way of example are possible within the spirit of my invention which shall be limited, therefore, only by the scope of the appended claims.

I claim:

1. A propeller spinner comprising a front shell and a rear shell, said rear shell including an interior bottom with a central opening for attachment to the rear of a propeller hub, and including also a set-off front end with an interior front flange, the rear end of said front shell overlapping said set-off front end of said rear shell, another flange interiorly of said front shell and connected therewith, a bulkhead with a cylindrical center portion for sliding engagement with said hub, a first set of screws securing said bulkhead to said front flange, a second set of screws securing said other flange to both said front flange and said bulkhead, and trap door provided openings in said frontshell forward of and in registry with the screws of said second set respectively.

2. A propeller spinner comprising a front shell and a rear shell, said shells fitting together so as to form a continuously curved surface, said rear shell including a bottom attachable to the rear of a, propeller hub, a first flange interiorly of the front end of said rear shell and a bulkhead having a second flange facing said first flange, said front shell including a third flange interiorly of its rear end and facingsaid second flange, said three flanges being shaped as zones of cones arranged inside each other and having their apiceson the spinner axis in front of the cone bases respectively, anchor nuts secured to the rear sides of said first flange, headed screw bolts penetrating said flanges and being screwed into said anchor nuts respectively from the front, the

bolt axes being directed substantially normal to the flange surfaces, and trap doors in said front shell to make the bolt heads accessible from the front side.

3. A propeller spinner comprising a front shell and a rear shell, said shells fitting together so as to form a continuously curved surface, means in connection with said rear shell to secure it to a propeller hub, a plurality of releasable means interiorly of said shells to secure said shells to each other, a trap door coordinate to each one of said releasable means in said front shell so as to make said releasable means accessible, a spring-provided hinge for each trap door, said hinge being attached to the inside of said front shell, and a detent to hold said door open against the restrain of said spring, said detent being accessible through the opening in the front shell to remove it from catching position;

HENRY G. JUNGER.

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