US2835348A - Retarder device - Google Patents

Description

May 20, 1953 c. B. sADTLER 2,835,348 RETARDER' DEVICE Filed Jan. 10, 1957 4 sheets-sheet 1 INVENTOR. CHESTER B. SADTLER BY r ,7 F ig. 2

WMRM

May 20 1958 c. BSADTLER 2,835,348

RETARDER DEVICE Filed Jan. 10, 1957 I5 4 Sheets-Sheet 2 Fig. 5

INVENTOR. CHESTER B. SADTLER May 20, 1958 c. B. sADTLl-:R 2,835,348

RETARDER DEVICE Filed Jan. 10, 1957 INVENTUR. CHESTER B. SADTLER mt TTUR/VE V5.5/

4 Sheets-Sheet 3 May 20, 1958 c. B. sADTLER RETARDER DEVICE 4 Sheets-Shea Filed Jan. 1o, 1957 United States Patent O (Granted under 'llitie 35, Uu S. Code (1952), sec. 2556) The invention described herein may be manufactured and used by or for the Government of the United States of Amerlca for governmental purposes without the payment of any royalties thereon or therefor.

The present mvention relates to a retarder device and Vmore particularly to a retarder device employing an arrangement whereby the bending strength of replaceable metallic members is utilized for resisting relative movement of components of the device.

This application is a continuation-in-part of a co-pending U. S. application of Chester B. Sadtler, Serial No. 357,650, tiled May 26, 1953, now Patent 2,788,090.

The present invention is especially adapted for use in launching missiles wherein booster motors are employed to impart initial acceleration to the missiles. In such cases, it is desirable to provide a means for preventing the booster motor from applying large shock loads to the missile, and accordingly, a retarder device is provided whereby the accelerating force of the booster motor is gradually applied to the missile. One portion of the retarder device is secured to a member which is suitably fixed to the ground or other supporting structurc, and another portion of the device is connected to the booster motor. When the booster motor is tired, it will cause that portion of the retarder device which is secured thereto to release from the other components of the device and allow the booster and missile to proceed unimpeded in flight. As the retarder device releases, a restraining force is applied to the booster motor which prevents excessive initial acceleration thereof and consequently large shock loads are not applied to the missile.

ln the aforementioned co-pending application, the retarder device utilizes V-shaped llexure bars made of deformable material, each leg of the bars being bent under tension beyond its elastic limit during the retarding action by means of a gear and rack pull-out assembly. It has been found that some features of the prior construction presents disadvantages which are overcome by the present invention. For example, the V-shaped exure bars can be replaced by a pair of straight tlexure bars facilitating manufacture and assembly with a saving of cost and time. ln addition, the relatively complex gear and rack pull-out assembly can be replaced by two cooperating bearing surfaces which also eliminates the need of means for maintaining the proper mating of the teeth heretofore found necessary. The retarder device can be constructed so that the ilexure bars can be deformed under compression, instead of only tension as previously disclosed, eliminating means for anchoring the bars in their supports.

An object of the present invention is the provision of a new and novel retarder device which reduces the friction between components thereof to a minimum.

Another object is to provide a retarder device wherein the restraining force which it will provide may be accurately predetermined.

A further object of the invention is to provide a retarder device which will release at a desired position.

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A still further object of the invention is the provision of a retarder device which is simple and inexpensive in construction, yet is sturdy aai reliable in operation.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. 1 shows a front elevation view of a preferred embodiment of a retarder device at an initial position prior to the start of the retarding action;

Fig. 2 is a side view of Fig. l;

Fig. 3 is a perspective View of one of the hinge plate components of the device;

Fig. 4 is a similar View of the retarder device of Fig. 1 at the end of the retarding action;

Fig. 5 is a partial enlarged sectional view of the bearing surfaces taken along line V--V` of Fig. 2;

Fig. 6 is a front elevation view of a modified retarder device at the start of the retarding action;

Fig. 7 is a longitudinal section of Fig. 6 at the end of the retarding action;

Fig. 8 is a graph showing load vs. displacement curves for each of the various illustrated modications of the retarder device;

Fig. 9 is a front elevation of another modified retarder device at the start of the retarding action; and

Fig. lt) is a similar view of the retarder device in Fig. 9 at the end of the retarding action.

Referring now to the drawing wherein like reference numerals designate like or corresponding parts throughout the several views, there is shown in Figs. l*5 a retarder device S comprising a support member 10 adapted to be fixed by threads 11 to a ground support, not shown. Member itl supports at least one pair of tlexure bars 14 and, as in the co-pending application, these ilexure bars may be formed of an annealed, low carbon steel, brass or other lsimilar moderately ductile material capable of bending to provide the desired retarding action.

As viewed in Figs. 1 and 2, retarder device 8 has lateral symmetry about a vertical axis 13, and two pairs of ilexure bars 14 and 14 are preferably employed, one pair of bars being on each side of axis 13 as shown in Fig. 2.

Hereinafter in the specification the description will be limited to one pair of ilexure bars 141 and their associated components as shown in Fig. l, and this description will apply equally to the lateral and identical pair of ilexure bars 14 and their components being identified by the same number with the addition of a prime.

It will be noted that each pair of ilexure bars conslsts of two individual straight bars as compared to the V- shaped conguration in the aforementioned patentapplication. The ends of flexure bars 14 are detachably A` anchored in fixed support 10 by a keyway joint consisting of a slot 12 in which is formed oppositely disposed anges 1S each capable of engaging a complementary slot 16 on the corresponding sides of the flexure bars. The sides of slot 12 are slightly canted with respect to axis 13 so that the opposite ends of the llexure bars are supported in a diverging and spaced relation being maintained therein by a removable wedge 17. Instead of utilizing a separate removable Wedge 17, the wedge can be incorporated as an integral portion of one or both of the flexure bars.

The opposite ends of flexure bars 14 are detachably supported in a pair of movable support members Z5 by a keyway joint similarly provided in the opposite ends, one support member for each fiexure bar. Support members 25 are swung apart to bend the tlexure bars and provide the retarding action by a pull-out bolt 46 forming a part of the missile or the like being retarded until released by a mechanism presently to be described.

Each movable support 25 is provided with an integral diverging extension 27 terminating in an inwardly directed flange 30, the extension of each pair of movable supports forming an inverted V. The degree ot divergence of extensions 27 will depend 'on factors latertobe described. A hinge plate 32, shown in detail in Fig. 3, hasanY enlarged base portion supported on and extending between the iianges of corresponding movable supports 25, 25' of each pair, and, accordingly, one pairlof hinge'platesSZ are utilized for'thetwo pair of liexure'bars. The hinge plates are hinged'toiianges 30 by straps 36 supported'in opposing slots `37 `machined in the respective members. Straps y36arefpreferably made of a similar ductileirnaterialasllexure bars 14and -provide a flexible andfrictionless hinge, and, yas the flexure bars, arereplaceable after each retarding action. VVThe two hinge plates 32'. also form an' -inverted V substantially parallel to movable support extensions 27. An end offeach plate 32 opposite the hingedend isformed with a pair of lspaced rolleriportions 3S and 38, having a combined width reduced sutln ciently to be interposed in the space between the two pairs of iiexure barsfl'4' and 14', as shown in Fig. 2. Thetroller portionson one hingeplate are adapted to engage fthe corresponding roller portions on the other hinge plate throughout'the retardingfaction. vBetween each pair of roller portions the hinge plate is recessed and provided with la roundeb'earing surface 4b which, as a manufacturing 'expedienlmaycomprise portion-of a pin 41inserted through drilled apertures in the roller portions andthe recessedend'of the hingeplate. The longitudinalaxis of pins 40 are oifsetwithrespect to the longitudinal axes it their respective'rrollerportions to provide `anl eccentric relation therebetween. Each pin istmade of a suitably hardened material to'prevent excessive wear.

`A free Vend ofpull-out bolt 46`extends between the roller portions' of; both hinge plates `and is provided with an yenlarged-head portion 42 lhaving tapered 'camV surfaces 44 adapted to-engage pins 41 and bel restrained thereby. lt has been 'found thata tapered cam surface of 30 degrees with la plane normal to axis -13fwillprov-ide a satisfactory camming 'action with pin 41. Since a plane passing through hinge 36 andthe yinitial point of contact of the bearingsurfaces isxpferpendicular to cam surface 44, this plane also forms -a`f30 degree angle with axis 13. The extent of lateral movementof pins 41 by :tapered cam` surfacesfare shown -inFigs'S and 4; 'the initial and innermost positionl of 'the' pins 'at thestart ofthe 'retarding" action being shown in Figs. l and 5, and the outermost position of the pins' at lthe end fof the' 'retarding action,l the release point'ofvpull-o'ut bolt' 46,' being shown in' Fig. 4.k Roller portions 38e'nable` bearing -pins 41 to be spread apart by rolling on'the tapered'cam-surfaces44minimizing friction therebetween. 'Hinge p1ates32V are in'a position substantially normal toaxis 13 at the point -ofseparation shown in Fig. 4,-atwhich'tiniepins-M have'been spread apart the widthV of pull-outl bolt'46=re'leasingy the-'latter from the retarding device.

For'any given size-ilexure bar, the amount of initial resistance offered bythe retarder -device Ywill depend on angle` D, beingthe angle vof intersectionl of a planepassing through exible hinge'st'rap 36 andthe center of flex'ureY of each bar andlavvv plane passing lthrough strap 36 and lthe initial pointof contactbetween pinA 41-`1ar1d cam-surface" 44. For example,decreasing angleK D will increase the 4initial resistance of they r'etarder'devicey to theV-missileor other object being retarded.

rThe free 'end ot pull-out bolt 't6 Vmay be`of a'flength sufcient to extend freely'vinto a corresponding Krecess` 50 in yoke and yoke sleeve 51 so as to guide'the m'ovement of the pull-out bolt alongaxis'13 during Ythelretarding action, and, their abutment Vmaybe utilizedt-o' initially position bearing surfacesf4tl and44. VThe free endiof =the pull-out bolt l46 may be rectangular in cross section to prevent rotationduring 4longitudinal I displacement.

Operation ot" retarder device 8 isa apparent V `from`l Figs.

'l and 4. When the missile is tired tension is applied to bolt 464 which advances along axis 13 in the direction of the arrow (Fig. 4) applying a force on pins 41 and to their respective hinge plates 32. The initial perpendicular relationship between the hinge plates and the respective cam surfaces enables the device to absorb the maximum load at the start of the retarding action. A horizontal component of the force is transmitted to the tiexure bars through hinge plates 32, bending the bars under tension which supplies `the retarding action. As the pull-out bolt 46 is withdrawn, bearing surfaces 40 of pins 41 are advanced outwardly along cam surface 44 by the swinging action of'hinge plates 32 about their roller portions 38. The reaction of the flexurebars to thebending force maintains roller portions 38 in contact.

When the pull-out bolt 46 has advanced to a portion Where the point of contact of rollers 33. are substantially in a plane passing through hinge straps 36, pins 41 have advanced on cam surtaces'44 to aposition where the distance therebetween is approximately the same as ythe widthof'head'portion-42, .at which point pull-out bolt 46 is released 'ending the retardirng` action.

The retarder device can be readily restored to an operative condition by replacing iiexure bars 14 and hinge straps 36. As pull-out bolt 46 remains with the objectbeing retarded, this invention enables bolt 46 to be simple and light weight, vwhich are important considerations in missile applications.

lInthe modification of Figs. 1-5, -tlexure bars 14 are bent under superimposed tension during the rctarding action necessitating a keywaymeans or thelike for anchoring the ends of the tiexure bars in their respective supports. In Figs. 6 and 7 the componentsof the rei tarder device "58 for the .most part are the same as in sides of the frame being open .at 63 to permit lateral movement of `the parts. Oneend of each exure bar 64A is `seated in a corresponding recess 62 formed in the opposite end of the frame, the other end of each bar being received in similar recess 62 formed in movable supports 65. A hinge plate 66, which can be identical lin configuration as hinge plate'32 (Fig. 3), is hinged to each rotatable support 65 through flexible hinge straps68.

A pull-outbolt extends freely through opening 71 in fixed support 60 and terminates in a head portion 72 having tapered cam surfaces.74 on each side thereof for engaging respective bearing pins 76 mounted in hinge plates 66 and roller portions'78. As before, the longitudinal axes of hinge plates 66 are perpendicular vto their respective cam surfaces74 at the initial position. If desired, head portion 72 can be extended and support 60 provided with a suitable sleeve to.guide the free end ofthe pull-outbolt throughout the Vretarding action, as

in-the prior modification. Itwill. be noted that because of the arrangements of thecomponents, pull-out bolt 70 is of necessity longer than bolt 46 in the prior modication. The operation otv the embodiment of Figs. 6 and 7is substantially the same as previously described in the device of Figs. 1-5 with the exception thatfexure bars 64 are arranged to be-bent under compression, rather than tension,'throughout the retarding action; the;flexure bars being maintained in their respective supports by the compressive forces acting on'their ends.

Fig. 8 is aigraph showing the relationshipbetween load in pounds on the several retarder devices-of vthis invention plotted as ythe ordinate, and: displacement `of each respecasses-is tive pull-out bolt in inches as the abscissa. Curve A represents the load-displacement relationship for the retarder devices of Figs. 1 5, '.vhile curve B is the same relationship for the modification shown in Figs. 6 and 7. Both curves A and B have a similar and pronounced curvature indicating that the respective retarder `devices produce .a non-uniform retarding action. t However, in some installations, such as in guided missiles, a non-uniform retarding action may be undesirable in producing a shock on delicate components and changing sensitive adjustments. A retarder device S8 of Figs. 9 and i0 will satisfy such requirements byproducing a unifo-rm load-displacement curve as shown by curve C in Fig. 8.

As in the prior two retarder modifications, the various -components are substantially the same differing principally in arrangement of components. The arrangement of the device of Figs. 9 and 10 is similar to the retarder of Figs. 1-5, and in both of these modifications the exure bars are bent under tension. However, the device in Figs. 9 and 10 produces a uniform displacement of the pull-out bolt throughout the retarding action shown by curve C in Fig. 8, whereas, the retarder of Figs. lproduces a non-uniform displacement as shown by curve A.

Retarder device 88 comprises a fixed support 90 having a central attaching bolt 9i and a pair of longitudinal slots 92 one on each side thereof capable of supporting a pair of spaced iiexure bars 94. As in the prior modifications, shown in Fig. 2, a second pair of laterally arranged slots and iiexure bars can be provided in this device and need not be illustrated. Flexure bars 94 are detachably anchored in their respective slots by means of a slidable locking pin 95 engageable with corresponding semi-circular grooves in the fixed support and bars, being similar to the keyway construction of the device of Figs. 1 5. The other end of each iiexure bar is similarly secured by a locking pin 95 to a movable support 96.

Each flexure bar f4- is supported along a substantial portion against a shoulder 97 of the fixed support, one corner 97a of the shoulder being curved to form a bearing surface for the bars during the bending action. Each pair of flexure bars are suiiiciently spaced apart to house therebetween a pair of hinge plates 98 similar in design to the hinge plates 32 and 66 of the previous modifications. One end of the hinge piates 93 are connected to their respective movable supports 96 through flexure straps 100, and the other ends of the plates are provided with roller portions MP2 in mutual engagement. Pull-out bolt MP4 extends between roller portions 102 and is provided with a head portion 106 having opposite cam surfaces 108 adapted to engage bearing pins 110 extending between the roller portions of their respective hinge plates. It is believed that the uniform displacement of pull-out bolt 104 obtainable with the retarder device of Figs. 9 and 10 is achieved by a relationship between the components providing somewhat equal distances between points X, Y, and Z forming substantially an equilateral triangle. Point X is the iiexure point of hinge straps 100; point Y is the point of maximum bending of iiexure bars 94; and point Z is the point of contact between bearing pins 110 and cam surfaces 102. As in the prior modifications, a plane passing through hinge point X and the bearing point Z should initially be perpendicular to cam surface 108 and if the cam surface is a 30 degree slope, this plane will be 30 degrees from the longitudinal axis of pull-out bolt 104. It has been noted that although the retarder device of Figs. 9 and l0 provides a uniform displacement, as compared to the non-uniform displacement of the other two modifications, the iiexure bars 94 must be made somewhat larger than iexure bars 14 and 64 of the first two modifications to provide the same retarding force.

The retarder devices of this invention enable a preselected and predetermined restraining force to be applied to an object to be retarded. The invention devices are rug-ged, simple, and inexpensive in construction and operation. The devices are particularly suitable for missile applications, because that portion of the retarder device remaining on the missile is of minimum size and weight. The retarder components can be arranged to bend the iiexure bars under tension or compression forces depending on the particular configuration and requirements of any particular application.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the yappended claims the invention may be practiced otherwise than as specifically described.

I claim:

l. A retarder device which comprises a support member, means for iixedly securing said support member, an elongated deformable force-resisting member having one end mounted to said support member, a movable support member attached to the other end -of said deformable member, ra force-transmitting member hinged at one end to said movable support, a load member adapted to be secured to the object to be retarded, said force-transmitting member and the load. member having disengageable cooperating bearing surfaces for swinging said forcetransmitting member laterally against the movable support, means for guiding the movement of the load member, said deformable member and force-transmitting member being so disposed as to form an angle greater than zero degrees and less than degrees between the intersection ot' a plane passing through said hinge and the point of maximum bending of the deformable member and a second plane passing through the hinge and the point of contact of said bearing surfaces, the force-transmitting member and the load member at the start of the retarding action being so disposed as to form an acute angle lbetween the intersection of a plane containing the direction of force through the load member and said second plane, said load member being withdrawn from the device during the retarding action to increase said acute angle by flexing said deformable member until the bearing surfaces disengage to release the load member.

2. A retarder device which comprises a support member, means for fixedly securing said support member, a pair of spaced elongated deformable force-resisting members each having one end mounted in said support members, a pair of movable support members attached to the other end of said deformable members, a pair of forcetransmitting members hinged to said movable supports, said force-transmitting members having roller portions formed at the opposite ends adapted to roll with respect to each other, a load member adapted to be secured to the object to be retarded, said load member and force-transmitting members having disengageable cooperating bearing surfaces for swinging said force-transmitting members about their responsive roller portions, each deforma-ble member and corresponding force-transmitting member being so disposed as to form an Iangle greater than zero degrees and less than 180 degrees between the intersection of a plane passing through said hinge and the point of maximum bending of the respective deformable member and a second plane passing through the hinge and the point of contact of said corresponding bearing surfaces, each. force-transmitting member and the load member at the start of the retarding action being so disposed as to form an acute angle between the intersection of a plane containing tbe direction of force through the load member and said second plane, said load member being withdrawn from the device during the retarding action to increase each acute angle by liexing the deformable members until the respective bearing surfaces disengage to release the load member.

3. The retarder device of claim 2 wherein the angle greater than zero degrees is an acute angle, whereby said deformable members are under tension at the start of the retarding action.

4. The retarder device of claim 2 wherein the angle portions, the frespectivenol-ler,portionsofeach force-transmitting member adapted to be in rolling engagement throughout the retarding action, :said load rrrernlser` freely passing through the space formed between the encased roller portions.

7. A retarder device .which ,comprises a support member,V means for -xedly Securing said 4support member, a pair of spaced 'elongated deformable force-resisting members each having one end mounted .to said support member, a pair of movable `Support members attacheduto the other rend of said `deformable members, a `pair offorce transmitting plates hinged to said movable supports, said hinges being made of' deformable material, said forcetransrnitting plates having `roller portions formed at `the opposite ends and adapted to be `in rolling engagement throughout `theretarding action, a load lmember adapted to be lsecured `at one end to lthe object to be retarded and having7 an opposite end positioned between said roller portions, said force-.transmitting lmembers `and the load member having cooperative bearing surfaces for swinging said force-.transmitting members about their roller portions, said bearing surfaces ycomprising a curved surface and a ilat tapered surface, the longitudinal axes ofsaid force-transmitting plates being normal to the tapered bearing .surfaces at vthe `initial vpoint of contact between said bearing surfaces, each `deformable member and corresponding force-,transmitting member l.being so disposed as to form an angle greater than Zero degrees and less than 180 degrees between the intersection of a plane passing through said hinge and .the point of maximum bending .of the respective deformable member and a second plane passing through the hinge and the point of contactof said corresponding .bearingfsurfacesD ,each forcetransmitting member and the load member at the start of the retarding, action being so disposed ,as to form an acute angle between the intersection of a plane kcontaining the direction of force throughl the load member and said Second plane, said `lead member being withdrawn from` the device during ,the retarding action to increaseveach acute angle by flexing the deformable `members until the respective bearing surfaces disengage to release theload member.

8. A retarder device which comprises a support rnern ber., means for xedly securing said support member., a pair of spaced .elongated deformable force-resisting members having one end mounted to said support member, a pair of movable support members mounted tothe other end of said deformable members, a pair lof swingable force-transmitting members hinged to said movable supports, said hinges being made` of a deformable material, said force-transmitting members havingy roller.` portions formed at the opposite ends in rollingV engagement throughout the movement of the force-transmitting-members, said force-transmitting members having -cur'ved bearing surfaces arranged in spaced relation, aloadi-me'rnber adapted to be secured at one end to the object to be retarded and `having at the other end tapered-bearing surfaces positioned between and cooperating witbhfsaid curved surfaces, each `deformable member and corresponding force-transmitting member being so disposed .as to form an angle greater than zero degrees and lessthan 180 degrees between .the intersection of ya plane `passing through said hinge and the point of maximumbending of the respective deformable member and a second piane passing through the vrhinge and the point of contactfof said corresponding bearing surfaces, :each force-'transmitting member and the load member at `the start ofthe retarding action being so disposed as to form an acute ar1gle-between the intersection of a plane containinghtihe direction of force through the load member Yand said second plane, said load member being withdrawnvfrom n the device during the retarding action to increase each acute angle by flexing the deformable members until the respective bearing surfaces disengage to release the load member, said force-transmitting members being swingable about the roller portions as the load member is withdrawn from the device until the curved bearing surfacesnhave been spread Vapart a distance equal to the width lof` the tapered bearing surfaces at which time the load member is released. i

.References Cited in the tile of this patent kUNITED vS"l`Al`-ES PATENTS 1,530,000 Kauffman Mar.v 17, 1925

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