US2406601A - Cushion mounting - Google Patents

Description

Aug. 27, 1946. G. w. FYLER 2,406,601

' CUSHION MOUNTING Filed April 21, 1943 Sheets-Sheet 1 Fig.1.-

' fv/ma m' I His Attorney.

Aug. 27, '1946.

Pig. 5.

a; k\\\\\ i 71/1/11 1//////////////////// G. w. FYLER CUSHION MOUNTING Filed April '21, 1945 2 Sheets-Sheet 2 H II" Inventor: George W. Fylev,

His Attorney.

Patented Aug; 27 1946 'oGeorge' W. Fyler; Stratford; 'assignor to General Electric Company, a corporation of New York Application Apriri, 1943; S'riai 'Noa 4831915 1 I My invention relates to cushion mountings for sensitive apparatus subjected .to severe shocks and vibrations and it has for its object to previde an improved cushion mounting having a large amount of flexibility along three mutually erpendicular axes.

Another object of my invention is to prance an improved cushion mounting for apparatus,

subjected to exciting vibrations having ag'iven frequency range, in which the resonant fre quency. of the mounting and supportedapp'aratus is maintained considerablylower' than the frequency of the excitirig vibrationsby causing the static deflectingfor'ce or the mass or the apparatus to set up shear stresses in a resilient supporting member.

A further object of myinventiorl to'proi idean improved cushion mounting in which the r sili'ent members thereof are subjectedtc shear ing stresses in all planes throughout a primary; range of deflection and to compressional stresses throughout a secondary range of deflection.

The features of my invention-Which I believe to be novel are set forth with partieularity in the" appended claims. My inventionitself, how-- ever, both as to its organization and method of operation, together with further objects and advantages thereof, may bestbe understood by ref-- ereiice to the following-description taken in connecti'on with the accompanying drawings.

Inthe drawings; Fig. 1 represents a-cushion" mounting according to my invention; Fi'g 2 is a modification'of the mounting shown in 1-;

Fig. '3 is a portion of a side elevationalview of a modificationof the mounting of Fig. 2'; Fig 4 is a sectional elevation view along the-line 4 d of Fig. 3; Fig. 5 is a sectional View" alongtheline 55 of Fig. 4; Fig. 6 is a sectional elevation View of the mounting of Fig. 3 along the lines li -6; and Fig. 7 is a sectional view of the mounting' along the lines l 'l of Fig. 6.

Referring to Fig. l, I have shown a member Ill which is supported by a fixed supporting means H. The member It maycomprise any sensitive apparatus, such as a'radio equipment; and the supporting means" H'may be subjected to undesirable vibrations and sudden impulse shocks. In order to prevent these vibrations frombeing imparted to the" member ID a1 pair of transverse resilient members [2 and I3 are interposed between the member Ill and the sup porting means I I. The resilient members I2 and l3 may comprise circular rubber blocks or pads. The rubber member i2 is; securedin any wen known manner, as by bonding during-vulcaniza- 8' Claims; (01. Meats) A thin, to a, nietal'stiid l4,'the' lower portion er which is in threaded engagement with cooperat ih'g'th'reaidsin the supporting block H. A lack nut i5 is provided rigidly to secure the stud I4 3 to'Sdpporting/block II; The outer edgesof the circular washer i2 are similarly bonded by vulcanization toth'e inner surface of a cylindrical metal member I6; A second: cylindrical metal member H is attached to the apparatus It by means of screws IBand is spaced from the upper V irfac zof metal cylinder I6 by means of a rubcer tiocksla; Block l3; similar'to ritbber member" 12', is b'ond'edto the upper surface of cylinder l6 and the inner surface of cylinder 7.

It iswell-known that when a mass is supported by aresilientmember, the mass causes a certain deflection in." the resilient mounting and the amount of this deflection can be used to calcu- "he resenan't frequency of the system. For mass tlie relationship is substantially and as the ma'gnitu'de' of the initial de fie ti on'inreases, tiie'reson'ant frequency 'of the system decreases. It is also known that the am plitu'de of vibration-fer such a system is greatest when tile f equency or an exciting vibration is the resonant ire system. For e 2: citing vibratien eta y greater than the resonant frequency or the s stem, the amplitude of ililoratiort 0f the 'SZS Ste'ln drops and may ome considerably smaller than that er the eii-tihg vibration; H

From tnerore cmg t is seen that; order to protect system agamst vibrati ns over a eq eiicy range-, it"is" desirable to have the it frequency er the system considerably law-er than the lowest-"frequency of; that range so" tnat tne ampiitdde o vibration or the system eta-11s lowest" freq 'ricy is -riot greater than that of the xtiting so I and is considerably less than the higher frequencies the range.

In order that} the resonant frequency of the system (shown: in Fig?- l)' may be kept below a i ind um"value the resilient: tubers or the st c moimtine" elocated iii transverse planes so tirtfcr'ws any directioniniti ally he; resuint members.

- I ave-meal iste,- wan-e member [3 is; subjected to Shearing stresses by hers 2 and" l sprovics shear v c'tioiis; since a force in any directiofimayte rescived intc components in vertical and horizontal planes.- Sincethe' stiffness of arutbe'rmount shear is approximately only one-fifth as great as the stiffness in compression, it is apparent that a mount constructed in accordance with Fig. 1 produces a large initial deflection and the resonant frequency of the system is kept to a low value.

When the mount of Fig. 1 is subjected to a force in a given direction, for instance, a force F acting to the right in Fig. 1, the rubber block 53 is subjected to shearing stresses over a given range. When a predetermined longitudinal deflection of block I3 is obtained, the inner surface of the vertical wall of member I! contacts the outer surface of the vertical wall of cylinder IE to compress the rubber member 12. Thus, when the shear range of block I3 is exceeded, the unit changes over to a gradual compression, or snubbing, action. Similarly, for a force acting downward on member l0, rubber block I2 is initially subjected to shearing stresses until the bottom edge of cylinder l6 contacts the upper surface of supportin member Thereafter, the rubber block I3 is subjected to compression stresses untihultimately, the lower edge of cylinder l'l contacts the upper surface of member Such a cushion mounting provides a flnal limit to the deflection without any discontinuities in the cushioning action to affect adversely the member Hi. In a practical system, when a cushion mounting of the type shown below the member id in Fig. l is also used above the member l9, this member, which may comprise sensitive control apparatus, is protected by two units working oppositely to cushion the apparatus against shocks and vibrations from all directions.

In Fig. 2 there is shown a modification of the cushion mounting in which two channel shaped members 25 and 26 are transversely disposed. The supported member 25 may be bolted to an object to be supported and supporting channel 26 may be bolted to a fixed support. Rubber blocks 2'! and 28 are secured to the opposite sides of channel 25 and rubber blocks 29 and 38, to the opposite sides of channel member 26. The top and bottom faces of these rubber blocks are inclined at an angle to the horizontal so that the blocksfli and 28 support channel 25 in an elevated position. Rigid members, such as angles 3| and 32, are secured to the outside faces of rubber blocks 2'! and 28 and are bolted to the rigid angle members 33 and 34 secured to the. outside faces of rubber blocks 29 and 30. In this manner the angles 3|34 form a unitary structure which acts as a substantially rigid member interposed between the resilient members 2'! and 23 and the members 29 and 30. Accordingly, forces acting on the structure of Fig. 2 in the direction of F cause, initially, shearing stresses in the members 21 and 28 and produce a longitudinal deflection of these members. In order to limit the longitudinal deflection of members 21 and 23 to a predetermined amount, aswell as to provide means to change from shearing stresses in the members 27 and 28 to compressional stresses in members 29 and 34, the protective straps 3E and 3'! are secured, as by welding, to the angles 3| and 32. Similarly, to limit to a predetermined value the deflection of resilient members 29 and 3|], due to forces acting along the direction of the axis of channel 26, protective straps 38 and 39 are secured to angles 33 and 34.

After a predetermined longitudinal deflection of members 29 and 34, the channel 26 contacts strap 38 or 39 to initiate compressional stresses in resilient member 21 or 28. Q

In the cushion mounting shown in Fig. 3, a

channel member 40 of considerable length is supported by a plurality of shorter channel members 4|, 42, 43 disposed at right angles to member 48. Details of the cushion mounting used with the channel members 43-43 are pointed out in the following description of Figs. 4-7. In the several Figs. 3-? corresponding parts have been indicated by corresponding reference numerals.

Referring to Fig. 4, I have shown the cushion mounting for supporting body member 45 on a fixed support 46. A metal block is provided within the elongated channel 44) and contains suitably shaped recesses 56 to receive the heads of bolts 51 used for securing the channel 4!} and the block55 to the supported member 45. A metal pad 651s interposed between the upper surface of channel 40 and the bottom of the supported member 45 for purposes pointed out later. In the manner described in connection with the cushion mounting of Fig. 2, channel 40 has attached to it a pair of resilient members 59 and 64 and a pair of angle members 6| and 62 are attached to the opposite faces of these resilient members.

The elongated channel 4|, as seen in Fig. 5, similarly contains a metal block 41 having recesses 48 for the reception of the heads of bolts '49 provided to secure rigidly the channel 4| and the block 41 to the support 48. Also, channel 4| is mounted on a metal pad 54, whose function is pointed out later. Similar to the structure shown in Fig. 4, the portion of the cushion mount shown in Fig. 5 is provided with resilient members 58, 5| and angle members 52, 53.

A metal plate 63 of substantially the same length as channel 40 is interposed between the opposing faces of angles 52, 53, and angles 6|, 62

and is held rigidlyin this position by fastening bolts 64 extending between the supporting angles 6|, 62 attached to channel 40 and angles 52, 53 attached to channels 4 |-43.

In order to provide means to cushion the channel 4| and the metal block 41 from the metal plate 63, a rubber pad 61 is placed under the plate 63 and extends along this plate directly above the channel 4|. Similarly, as may be seen in Figs. 4 and 6, in order to prevent the channel 40 and the block 55 from striking against the plate 63, a rubber pad 66 is placed upon the plate 63 and extends along this plate directly beneath the channel 49. The rubber pads 66 and 61 may be attached to the plate 63 by any suitable means, such as the locating projections 68 formed integrally with pads 86 and 61 and extending Within cooperating holes provided for that purpose in the plate 63. g

In order to provide means to limit vertical deflection of the cushion mounting of Fig. 3, as well as to provide means responsiveto predetermined longitudinal deflections of one set of resilient members to produce lateral deflections of the transverse set of resilient members, T-headed bolts ll and it, best seen in Figs. 6 and'l, extend respectively between the supported member 45 and plate 63 and between support 46 and plate 653. The belt m passes loosely through hole 16 in block 4'l and is in threaded engagement with support 46, being securely fastened thereto by means of nut 12. It passe through rectangular supported member 45, being securely fastened thereto by means of nut '14. The head of bolt ll likewise passes through a rectangular slot in plate 63 and pad 65 to project between the channels 43 and 42. After being passed through the openings 53 and 75 in plate-63, the T-headed bolts 18 and H are turned so that the longer axes of the heads of these bolts aretransverse to the longer sides of the rectangularopening f3 and 75. I

When the cushion mounting illustrated in Figs. 3-7 is subjected to a force, for example, to the left in Fig. 3 along the axis of channel 43, the resilient members 55-3 and fill are first subjected to shear stresses. After the force has produced deflection of apredetermined amount of members 59 and 6d, the neckcf bolt H engages the end of slot E5 in plate 63 If the force is sufficient to produce further deflection, the bolt 'il, acting through the plate 63 and angle 53, compresses the resilient members 5!. Ultimately the side of slot 75 of plate $5 strikes the neck of bolt Id to prevent further movement of the mounting.

I a similar manner, force transverse to the axi of channel dd produce, in sequence, shearing stresses in rubber members 50 and 5!, contact of bolt is with the end of slot 13, compression stresses in resilient member 69, and finally contact cf bolt '1! with the side of opening 15. It is apparent, also, that forces acting downwardly in a vertical plane, such as the force F" inrFig. 3, initially produce shearing stresses in members 59, L l and 59, 69. After a predetermined deflection of these members, metal blocks El and 55 compress rubber pads 67 and 66. Metal pads 54 and 65 function to prevent angles 52, 53 from contacting support 45 and angles BI, 62 from con.- tacting supported member 15 until pads b6 and 5'1 are fully compressed. Vertical movement downwardly ceases when the vertical legs of angles 52, 53, 6!, and 82 contact the horizontal surfaces of members 65 and 46. Vertical deflections upwardly set up shear stresses in members 5i}, 5!, 59, and 6?! until further upward movement is prevented by the heads of bolts Ill and H contacting metal plate tit.v

It is thus seen that my invention provides a cushion mounting in which, by proper selection of the mass of the elements of the mounting and the use of resilient elements in shear, the resonant frequency of the mounting is adjusted to a value lower than that of the lowest frequency in the range of vibrations to which the mounting is subjected. The cushion mounting further provides means for initially absorbing all deflecting forces by the setting up of shear stresses in certain of the resilient elements and, after initial deflection of these elements, by causing other resilient elements to be compressed. In this manner any secondary shocks to the system which would occur through sharp discontinuity of the,

resisting force are avoided.

While I have shown a particular embodiment of my invention, it will of course be understood that I do not wish to be limited thereto since various modifications maybe made, and I contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A cushion mounting for a member supported by means subject to undesirable vibrations comprising, a pair of transvers resilient members interposed between said member and said supporting means, said resilient members being mounted to set up shearing stresses opposing forces applied thereto along three mutually perpendicular axes, and means responsive to'predetermined longitudinal deflections of one of said resilient members to produce lateral deflections of the other of said resilient members, said last means comprising a rigid structure attached to both of said resilient members, said rigid structure being arranged to contact said supported member after said predetermined deflections and to compress said other resilient member between said rigid structure and said supporting means.

2. A cushion mounting for a member supported bymeans subject to undesirable vibrations comprising, a pair of transverse resilient members interposed between said member and said supporting means, mean to'limit vertical deflections ofeach of said resilient members comprising a rigid structure attached to both of said resilient members and arranged to contact both said supported member an'd'said supporting means after predetermined vertical deflections of said resilient members, and means attached to said structure to produce lateral deflections of one of said resi-lient members after a predetermined longitudinal deflection of the other of said resilient members.

3. A cushion mounting for a member supported by means subject to undesirable vibrations comprising, a pair of transvers resilient members interposed between said member and said supporting means, and means responsive to predetermined longitudinal deflections of either of said resilient members to produce lateral deflections of the other of said'resilient members, said last means comprising a rigid structure attached to both of said resilient members, said structure being arranged to contact said supported member after said predetermined deflections to compress said other resilient member between said rigid structure and said supporting means.

l. In a cushion mounting for a supported member, the combination of a first resilient means attached to said member, saidmean extending in a direction parallel with said member and being subjected to shear stresses by forces acting on said member in said direction, a second resilient means mechanically connected to said first means and extending in a second direction transverse to said first direction, said second means being subjected to shear stresses by forces acting on said member in said transverse direction, and limiting means attached to each of said resilient means whereby when the deflection of one of said resilient means due to said shear stresses equals a predetermined value the other of said resilient means is subjected to compressional stresses, both of said resilient means being subjected to shear stresses by forces acting on said member in a direction transverse to said first and second directions.

5. A cushion mounting for a member supported by means subject to undesirable vibrations comprising, a pair of transversely disposed channel shaped members, one of said channel members being fastened to said supported member and the other of said channel members being fastened to said supporting means, resilient means attached along the sides of each of said channel members, substantially rigid connecting means interposed between said resilient means, and means responsive to a predetermined longitudinal deflection of either of said resilient means to produce a lateral deflection of the other of said resilient means.

6. In support, the combination of a pair of transversely disposed channel shaped members, a substantially rigid member positioned between said channel shaped members, resilient means attached along the sides of each of said channel members and connected to said substantially rigid member, said resilient means being mounted to set up shearing stresses opposing forces applied to said channel members along three mutually perpendicular axes, means responsive to a predetermined longitudinal deflection of either of said channel members to produce a lateral deflection of the other of said channel members, aid last means including means to limit the motion of said channel members along each of said axes.

'7. A cushion mounting for a member supported by means subject to undesirable vibration comprising a pair of transverse resilient members interposed between said member and said supporting means, a substantially rigid connecting means interposed between said resilient members, said resilient members being mounted to set up shearing stresses opposing forces applied to said supported member along three mutually perpendicular axes, and means responsive to a predetermined longitudinal deflection of one of said resilient members for producing compression of the other of said resilient members, said last means comprising rigid overlapping members positioned on opposite sides of said one resilient means for directly contacting said supported member after said predetermined deflection.

8. In a support, the combination of a pair of transversely disposed channel shaped members, resilient means attached along the sides of each of said channel members, substantially rigid connecting means interposed between and connected to said resilient means, said resilient means being mounted to set up shearing stresses opposing forces applied to said channel members along three mutually perpendicular axes, said connecting means including rigid members parallel with and partially co-extensive with said channel members, the points of connection of said resilient means to said connecting means being greater than the distance between said channel members and said connecting means whereby the setting up of substantial tension stresses in said resilient means is prevented.

GEORGE w. FYLER.

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