US2069858A

US2069858A - Mandrel for spinning metal

Info

Publication number: US2069858A
Application number: US718573A
Authority: US
Inventors: Squires John
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-07-05
Filing date: 1934-04-02
Publication date: 1937-02-09
Anticipated expiration: 1954-02-09

Description

Feb; 9, 1,937. J, sQUlREs I Y 4 v l2,069,858

MAHDREL Fon sf'NNING METAL original Filed Jll-Ly 5, 1953 Zaza.

M? mym;

Ammin/'5l f Patented Feb." 9, 1937 UNITED4 STATES PATENT oFF-ICE Original *application July 5,

1933, serial No.

679,133. Divided and this application April 2,

' 1934, Serial No. 718,573

(Cl. ID3- 52) 7 Claims.

.This invention relates to apparatus for spinmng metal and has particular relation to closing the open end of a tubular blank for airplane propeller blades, and is a division of my application 6 for Letters Patent of the United States for Improvementsv in propeller blade and method and apparatus for producing same, led July 5, 1933, Serial No. 679,133. Objects' of the invention include the provision 10 of an improved apparatus for closing the end of a tubular object byv a spinning operation; the provision of an improved mandrel for use internally of aA tube during' the operation of closing an end of the tube by a spinning operation; the provision of an improved type of mandrel for use internally of a tube the end of which is'to be closed by a spinning operation while the tube is in heated condition, and so constructed as to minimize the transfer of heat away from the end of the tube to be closed during the spinning operation; the provision of a. mandrell adapted to internally support the end of a propeller blade' blank during a spinning operation thereon to close such end; the provision oa mandrel adapted for insertion within theend of a hollow propeller blade blank during a spinning operation to close such end while such end is in a heated condition and so constructed and'arranged as to minimize the transfer of heat'from such end -to the mandrel; the provision of a mandrel for internal use within the end of avhollow propeller blade blank during the operation of spinning the end of the blank closed, the mandrel being formed with a portion to control the internal shape of the spun end portion of the blank and another-. portion for centering the mandrel in the blank y and reinforcing the blank internally against the application of pressure -from the outside; and the provision of a mandrel for a spinningvoperation comprising a main body portion corresponding in size, shape and contour to the interior walls of a portion of a tube to be received thereon, and an additional portion so constructed and formed that it has a relatively limited additional contact with the interior walls of the tube.

The above being among the objects of th present invention, the same consists in certain novel features of construction and combinations of parts to be hereinafter described with reference. to the accompanyingv drawing, and then claimed, having the above and other objects in view.

In the accompanying drawing which illustrates a suitable embodiment of the presentv invention 'tioned side elevational viewl of a blank for an air- 'plane propeller blade.

and in which like numerals refer to like parts l throughout the several different views,

, Figure 1 is a' partially broken, partially sec- Fig. 2 is a vertical sectional View taken transversely through the axis of the blank shown in Fig. 1 as on the line 2-2 of Fig. 1.'.

Fig. 3 -is an enlarged fragmentary sectional view of the small end of the blank shown in Fig. 1 10 and illustrating in part the apparatus employed for closing the small end of the blank and before such apparatus has acted upon such small end.

Fig. 4 is a view similar to Fig. 3 but illustrati ing in greater detail the apparatus employed in 15 the closing of the small end of the blank and i1- lustrating the small end of th blank after 'one of the initial closing operations thereon.

Fig. 5 is a view similar to Fig. 3 and illustrating the small end of the blank after a further 20 closing operation thereon.

Fig. 6 is a view similar to Fig. 5 and showing the small end of the blank after it has been completely closed.

Inone method of forming airplane propeller 25 blades as brought out in detail in the above referred to application of which the present application is a division, a cylindrical metal tube is acted upon to provide an outwardly projecting annular ang'e at one end and an inwardly ta- 30 peredend or nose at the opposite end. The tube is then subjected to suitable machining and/or other operations to predetermine its internal and external size, shape and contour and preferably to reduce the Wall thickness thereof from the 35 flanged end toward the small or nose end thereof without changing the cross-sectional shape of the blank. The smaller tapered end of the blank is then closed, and the blank is then placed between suitable dies and suitably acted upon to change 40 its cross-sectional shape to that desired in the nished product. The present invention dealsk solely with the closing of the small end of such' a blank. v

Referring now to Figs. 1 and 2, a blank such 45 as that above described is illustrated in a condition where its interior and exterior surfaces have been formed to predetermined size, shape and contour and as comprising a main body portion H2 having at one end thereof a shank por- 50 tion |04 and ilange |06 and the opposite end thereof being gradually tapered as at |34 to form a small end or nose without completely closing suchend. The radially extending outwardly projecting annular flange |06 in the particular ex-7 55 ample shown is provided for the purpose of per-V mitting the ultimate blade to be secured to a hub structure. The shank portion |00 varies from a maximum thickness adjacent the-nange |00 to a minimum thickness at its opposite end where -it merges into the main body portion |I2 in a smooth curve and acts to provide added rigidity and strength to this portion of the blade.

The wall thickness'of the main body portion Ii preferably decreases in'thlckness from its point of connection with its'shank portion i to the nose or small end thereof and this) feature is shown in the drawing. It will be understood that the entire blank is circular in cross section from end .to end as indicated in Fig. 2 and that the small end of the, blank is not completely closed initially, in order to permit greater ease in the machining, for instance, of both lthe interior and exterior surfaces of the blank. I

After the blank hasreached the stage of completion indicated in Figs.-1 and 2 and as described, the'next operation is to close the nose` or small end |34 of'the blank H2 and this is preferably accomplished by the use of a spinning operation such as is indicated in Figs. 3 to 6, in-

clusive. a a

In connection with the closing of the small end of the blank, it has been found desirable, although not necessary inall cases,.and particularly where the tip is relatively small, to increase the wall thickness of the blank at the extreme closed end portion thereof and also, although not necessary in all cases, to.provide a projecting nipple about -the point of closure for the reason that during pressing of the blank to blade shape a considerable amount of bending and stretching of the metal in the extreme endportion occurs, and ess a suitable amount of metal is provided at s` point, particularly where the small end of the blank is not relatively small, a crack isliable to develop in the finished article. l

In carrying out this spinning operation ithe blank l|2 is placed upon a mandrel indicated at 200 in Figs. 3 to 6, inclusive. This mandrel 200 does not necessarily need to contact with the interior walls of the blank H2 over the full length of the blank but in any case must have an end portion 202 which accurately nts and is properly centered in the inner end portion of the nose i of the blank. The extreme end of the portion 202 is rounded as at 200 into exact conformance with that desired for the interior surface of the end of the ilnished blank. Preferably, the end sur- 'contact with the mandrel.

center located as at 206. After the mandrel 20| has been thus formed it is preferable to cut it down or relieve it in diameter toward the tip. 'I'his relief, whichv is indicated at 202a, may begin a little over an inch'back from the 'tip and need not be very deep, as little as 5 thousandths of an inch having been found satisfactory. The purpose of this cut is to keep a material area of the end of the blank from actual and thermal It has been found that when the end of the blank is in complete contact with the corresponding portion of the mandrel it is diillcult to keep the end of the blank hot enough to be conveniently and properly worked. lBy cutting out the mandrel as shown the blank is kept from contact therewith except at such locations as arenecessary to the proper forming of the interior shape of the end of the blank during the closing operation and for the 'proper support of the end of the blank without -distortiomas will later be brought out, and the heat is not so readilyloonductea away from the portion of the blank which is to be spun.

The mandrel 200 with the blank II2 thereon is then mounted in a suitable lathe lor other turning machine which may include, as indicated in Pig. 4.a bed 203 upon which is longitudinally movable a main slide 2I0 upon which is a compound slide 2|2. The nose end of the blank may be suitably supported as by a steady rest 2M, care being taken in adjusting it to allow for anyv I subsequent expansion of the blank which may occur due to heatingthe tip thereof for the spinning operation. The steady rest 2 I0 is preferably v*located in alignment with that portion of the end202 lof the mandrel which has not been cut out so that undue pressure of the steady rest on the exterior of the blank will not distort the blank. A stop 2li, as indicated in Fig.'4, is preferably provided for engagement with the slide 2i! so as to limit movement yof the carriage 2li f and consequently the pivotal axis 2 I l of the compound slide 2i2 to the left asvviewed in the ngure. The stop 2i0 is preferably adjusted and fixed so that the pivotal center 2|. of the compound carriage 2 I2, and consequently the spinning tool 220 carried thereby, may be limited in its approach 'toward the center 200 of the end surface 204 of the mandrel by a distance indicated .in Fig. 3 at 222 equal to the added wall thickness desired for the extreme tip portion of the blank H2. i In operation, and referring now to Fig. 4, the mandrel 200 and yblank |I2 are rotated inthe lathe and llame from a torch such as '224 is played upon the end portion of the blank |I2 to l bring it to `a suitable condition of plasticity as," for instance that indicated by a bright red coloring ofl the metal at the nose or tip. 'Ihe carriage 2li is moved to the right until the pivotal Y axis 2|! ofthe cross slide SI2 is spaced a distance s uch as 220 outwardly from its predetermined final -position as determined by the stop 2 I0, and the spinning tool 220 is then brought toa position such that when it is swung about the axis 2|. it will engage only the extreme endportion of the no |34 of the blank H2. lAs soon as the heat from the ilame of the torch 220 has brought the extreme end portion of the blankv to a sumcient condition' of plasticity,V as above described,

the compound carriage 2I2 and the tool 220 carried thereby is swung about the axis 2I0, preterably in a counter-clockwise direction as viewed `in Fig. 4, and thetool 220 thus coming in con tact with the extreme end portion of the nose or tip causes it to be spun in as indicated in Fig. 4. The main'slide 2li is then moved a short distance to the left, asviewed in the flgures,'until the distance 220-in Fig. 4 has been reduced, for instance, to a distance indicated at 228m Fig. 5 at which time the tool 220 is again `swung around lthepivotalaxis2I0tospin theextreme tip of the blade furtherinwardly as indicated in Fig. 5.

This movement of the main slide 2ll"carrying with it thespinning tool 220 is repeated as many times as is desirable or n, taking care that each'pass of the tool 22| is an "easy" pass l lsoastoinsureasmoothilowofthemetaloi'the possible. An excess-of metal is provided in the end of the blank so that the tip wall may be .somewhat thicker than the immediately adjoinduring these operations and may keep such end at such temperature that when the end isiinally closed, as indicated in Fig. 6, the metal of the tip may weld itself together at the line or point of closure.

The thickened end portion surmountedF by the nipple, 230 reinforces the end of the blank so that it may not break open under the stressesl produced when the blank is deformed into the blade form in the pressing dies employed in subsequent operations. Upon completion ojthe closing operations on the end of the blank the newly closed end portion of the blank is preferably polished and buied so as to bring it to the same condition of nish as the main body portion of the blank.

Formal changes may be made in the specific embodiment of the invention described without departing from the spirit and substance of the broad invention, the scope of which is commensurate with the appended claims.

I claim:

1. A mandrel for supporting a tube to be heated and spun closed at its end comprising a base portion snugly fitting the interior of the tube, a

body portion slightly smaller than the interior of the surrounding portion of the tube and adaptedv to be spaced therefrom throughout the spinning' operation to reduce transfer of heat between the tube and the mandrel; and an end of thesize and shape desired in the interior of the tip of the closed tube.

2. A mandrel foruse internally of a tube during a closing operation upon a heated end thereof comprising a member adapted to t internally of said tube adjacent said end thereof, an end of said meniber being shaped to control the internal shape of said end when closed, and said member being radially relieved axially between its ends to provide spaced zones of contact with the interior walls of said tube.

3. A mandrel for use internally of a tube during a closing operation upon a heated end thereof comprising a member so constructed and arranged' as to provide axially spaced contact zones for the interior walls of said tube and an intermediate portion relieved against contact with the tube during the closing operation to reduce transfer of heat between the tube andthe mandrel, one ofsaid zones adapted to control the interior shape of said end during said closing operation.

4. A mandrel for use internally of a tube during a closing operation upon a heated end thereof comprising a, member having a portion adapted to contact the interior walls of said tube to locate it therein, another portion spaced therefrom providing a form for the internal surfaces of said end when closed thereon, and a'portion intermediate the two rst mentioned portions adapted to provide a relief between the tube and the mandrel during the spinning operation.

5. *A mandrel for use internally of the tapered end of a tube during a closing operation on the end thereof comprising a portion externally conforming in size, shape and contour to the interior surfaces of a portion of said end and an axially spaced portion adapted for initial contact withv a limited length only of the interior walls of said end of said tube, the last mentioned portion being shaped to provide a form for said end during the closing operation thereon, and said member being radially relieved between said portions.`

6. A mandrel including a pair of axially spaced portions one of which approximates a frustrum v of a cone and the other of which is provided with