US1905252A - Railway car truck springs - Google Patents

Description

April 25, 1933. T' SYMlNGTON 1,905,252

RAILWAY CAR TRUCK SPRINGS Filed July 6, 1931 5 Sheets-Sheet l la; l j 3/ 30 42 a# l /9 4Z April 25, T* H 5YM|NGTON RAILWAY GAR TRUCK -S PRINGS Filed July 6, 1931 5 Sheets-Sheet 2 ATT NEY .Laad y Tousavds gf Penya/* RAILWAY CAR TRUCK SPRINGS Filed July 6, 1931 3 sheet-sheet 3 v gwomtoc Patented Apr. 25, l933 UNITED STATES PATENT OFFICE THOMAS H. SYMINGTON, OF BALTIMORE, MARYLAND, ASSIGNOB TO T. H.'SYMINGTON & SON, INC., F BALTIMORE, MARYLAND, A CORPORATION 0F MARYLAND ,A RAILWAY CAR TRUCK SPRINGS VApplication led July 6, 1931. Serial No.- 549,050.

The invention relates to railway car springs and has special reference to that type Alocated within the window openings of the side'frames for the purpose of yieldably supporting the bolster and of course the load thereon.

The 'principal object of the invention, generally stated, is to provide a spring assembly, arrangement or. combination of such character that either light, intermediate or heavy loads will be adequately supported and vibratory or jiggling tendencies checked.

It is well known that whenever a truck bolster is supported upon springs of an standard type there is alwaysa certain tenv ency of the springs to rvibrate vertically or jiggle. Vhen this movement builds up, the ciiect on the car and its lading is injurious.

extent when the natural period of vibration of the springs coincides or is synchronized with the frequency of the jolts or impulses caused by passage of the car wheels over the rail joints. This synchronization occurs at certain substantially definite critical car speeds depending upon the specificvcharacteristics ofthe particular springs used. In certain types of springs the critical speed may be several miles lper hour more or less than with other types. This jiggle .is of course affected and checked to a certain ex'- tent when the train speed is greater or less than the critical speed hummm-fortunately, in the case of long or solid trains the rate 0f acceleration or deceleration is not rapid land the result is that the destructive jiggle may continue for a considerable length of time, t possibly while the train is travelling'several 40 miles.- L Y Y I have discovered by exhaustive tests that by employing a spring nest embodying units of different natural periods of vibration and adapted to become successively energized,

that is to say wherein certain units support the load throughout a definite deflection with other units coming into play when the deflection exceeds a certain amount, a snubbing action can be produced which will bring about a change in the period of vibration ofthe The vertical jiggle develops to its maximum combination and Ithereby eiectually check or break up the objectionable jiggle.

It is with the above facts in view that I have devised the present inventionwhich has for an important object the provision ofa springnest which, considered as a. whole, is initially snubbed or maintained under a certain degree of compression, the snubbingy means bein rof a somewhatyieldable characterto cus ion excessivelysevere shocks.

Another important object of the invention is to provide a snubbed spring nest embodying units which do not come intoy play until the load exceeds a certain amount or until Vthe light load supporting springs are deiie'ctedI beyonda certain predetermined travel,l all' of the springs of course cooperatingto support heavy loads. J

Afurther object is to 4provide* a truck springassembly in which-,all of the' units 7o are of the helical type and conforming in at f/ least most respects to'standard practice as a regards pitch, `free height, size of stock, etc'.

f Another and more specific object isto provide a spring assembly including certain units which are positively held to the truck bolster by securing means passin through a portion of the latter, this means ein movable with respect to the side frame an being, moreover',` cushionedagainst excessively severefstrain.

` Still another Objectis to provide a spring arrangement in which use may be made of a side frame and bolster of the ordinary construction, the only change required bein rthe provision of holes in the seat portion o the side frame and in the bolster for the rece vtion of the'bolts which hold certain -of e spring units snubbed or under initial compression. f i" 1 vAn additional object is to provide'ar spring assembly which will be simple and inexpensive to mak,`easy to install, positive action, efficient and durable in service/,andi general improvement in the art.

To the attainment :of the foregoing and other' objects and advanta es, the invention" preferabl consists in the etails of construction and t e-arrangement and combination of parts to be hereinafter more fully described 100 and claimed, and illustrated in the accompanying drawings in which:

Figure 1 is a fragmentary elevation of a truck side frame having a bolster supported therein by my spring assembly, the bolster being in section and the. spring assembly 'being a section taken on the line 1 1 of Figure 4, A

Figure 2 is a vertical section taken on the line 2-2 of Figure 1, 1

Figure 3 is a view similar to Figure 2 showing a modification of the snub bolt cushioning means, l

Figure 4 is a plan view of the nest,

Figure 5 is `an edge elevation of one of the spring caps, I

Figure 6 is a detail section taken on the line 6 6 of Figure 4 andshowing only the cap in section,

Figure 7 is a diagram showing the working curves for spring nests of diierentcapac ities.

Referring more particularly to the drawings, I have shown a portion of a side frame including the usual compression members 10 and tension members 11 connected by the spaced parallel column guides 12 which define a window opening 13 through which extends the bolster 14 supported by my novel spring lassembly which is indicated asa whole by the numeral 15` and which is engaged between the underside of the bolster and the; spring seat 16vat the bottom of thewindow' opening.

In carrying out my invention I form the assembly 15 as a plurality of units or pairs of units designated as a whole by the numerals 17 and 18 -mounted between similar caps 19 centrally apertured as at 210 for the reception of a suitable tie boltnot shown, which may be used, initially, for the purpose of holding the nest assembled during handling'prior to installation in a. truck. The reason'why this tie bolt is not illustrated is because the assembly isshown in situ,`th e tie bolt being necessarily removed.

Each assembly or unit 17 comprises outer and inner coils 21 and 22, respectively, which may normally be of standard heightand uniform pitch. In actual practice the outer coil 21 may be the same .as a` standard Class Gr inner coil though there is not necessarily any restriction in this respect. The innermost coil 22 is made of smaller stock and in some instances may be omitted if desired, depending upon the capacity of the car beneath which the assembly is to be used. The two unitsl'', which are similar, are intended to be snubbed down or held under a. certain predetermined initial compression by means 0f bolts 2,3 which extend axially through the coils 22, through openings 24 in the spring caps, and through openings25 and 26 in the bottom of the bolster and the spring seat 16, respectively. The top of the bolster is shown as provided with openings 27 facilitating insertion of these. snub bolts. Beneath the spring seat 16 the bolts carry nuts 28 by means of which the degree of the snubbing action may be varied and made to accord with whatA is found in practice to be most desirable under the circumstances. As there is considerable strain on these bolts upon recoil, that is to say upward movement of the bolster Vafter deflection has occurred, I find it desirable to cushion them. In Figure 2 I have consequently illustrated rubber pads 29 located between the bottom Wall of the bolster and washers 30 which are located immediately under the. bolt heads 31. Of course there is no particular limitation as to the use ofl rubber pads as other means might be provided such for instanceas the s rings 32 showny in Figure( 3, these springs eing in' itially compressed to their maximum extent as clearly indicated.

To prevent turning movement of the bolts, to prevent them from having any looseness or jiggling and to insure that they will move with the bolster and slidethrough the openings 26 in the spring seat, I preferably providev retaining elements 33 in the nature of clips secured, for instance by rivets 34, to the top of the bottom wall of the bolster and extending along the facesof the boltl heads 31, Y

these clips being initially yin the position shown by dot and dash lines in Fi re 2 and being bent over as shown by full lines in the same figure to overlie the tops of the bolt heads as at 35. i

If the inner springs 22 are used, as illustrated in the drawings, the engagement of the bolts throughv them and the location of these springs within the outer springs 21 will operate to maintain all of the springs in their 'proper positions as the c annot become laterally ydisplaced in `any ever, in case the inner springs 22 are not used it becomes necessary to provide some other centering means. This is readily accomplished by pressing down diagonally opposite cornersof the caps 19 to form tangs 36 and stamping out ofthe caps other tangs 37, the tangs 36 and 37 being in embracing relation to the4 endmost coils of the outer springs 21. i Y C Eachunit 18 comprises an outer coil 38 of standard free height, for instance eight inches and whichimaybe actuallv a standard irection. How- Class G outer spring formed of stock suitv not become energized until the unts17'and the springs38 have been compressed lto a considerabledegree. y l i l In theuse of a spring nest, constructed 'as disclosed for fifty-five tonj'cars, it willbe seen that the entire nest isfundefr anV initial compression amounting in travelto yg'inch,

with an equivalent load'capacity of '10,000

pounds. This is always the initial starting point on the curve disclosed in Figure 7. rom this point, the curve rises in a distance of land 1/8 inches to a point where the short coils 39 of the units'lS come into action. The added capacitythus pickedup causes the line to rise more abruptly toa'total capacity of substantially 80,000 pounds. In other words, the spring units 17 and the outer springs 38 of theunits 18 support all ordinary loads and have a travel of 1 and 1/2 inches whereas the short springsfg have a travel ofi@ of an inch. When the Vcar is riding along on all ofV the springs with the exception of the short Springs, if there develops any jiggling tendency the springs 21, 22 and 38 will become deflected beyond a travel of 1 and 1/2 inches whereupon the bolster will strike against the V followers 40 and compress 'the springs 39 which, havinga different natural period of vibration and added to the capacity, will immediately snub or check the vibration and prevent the dangerous jiggle. f Referring still furtherto the graph, it will be observed that five' different car loads `have i been laid` out. The lightcar is underv lthe 10,000 poundsinitial load and may of course be expected toV ride rather roughlyv but this is immaterial as there isno lading to be protected. However, if the force. is built up in magnitude to about`20,000 pounds they will break through the snub andl retard anyfurther jiggling. When the next load is reached,

.which isabout onequarter capacity,vthe

spring may vibrate downwardly' and upwardly one-fourth inch each way, On the up vibration the springs will be abruptly snubbedby the bolts 23. For Vthe next load, approximately one-half it willbe noted that the car may vibrate downwardly andup- Wardly approximately one-half "inch `each way `before the upward snub is reached. If the upward snub fails to `check the vibration, it will be checked when it reaches the break in the spring line. At about threefourths load, the springs will have to be closed substantially 1% inchesk before 4being Y checked by the pick-up in capacity causedbv the breakin the dine. If this were to .fail and the spring were to oscillate through this point it would again be checked by the up ward jump on the boltsf`23. The same `is true for the full load limit of the car, but in so far as these masses aregradually increasing vit is advisableto decrease ythe distance.`

through which these masses travelbefore they strike' some means for checking synchronous 'vibrationjof the springs. If a line were projected beyondthe 42,400 pound load in the graph it Will befobserved 'that the angle subtended between this line and the iinal closure curve will be'about 22. This will correspond to abouty an eight 'or' ten;

mile change' in critical speed. It is this change in critical lspeed which? should and will break up harmonics and the greater this angle is thegreate'r is the possibilityof `acc'omplishin the desired result.

'Itwill o coursebe Vnecessary to make some modification of the spring assembly to take care of cars -r ofl diii'erent capacities so that the performance will 'be 'in' accordance with the graph, Figure 7, and'this caribe readily done by' changing the size ofthe stock `from which the various springs 'are formed. vFor a forty ton car thecoils 38ma be of 1 'andi/1 v inch stock'whereas Vfor'the fi ty-five ton and seventy ton land 1/2` inch stock`will be more suitable in order that'adequate protection may be had against excessive loads. In forty ton equipment the springs 22 -may be omitted if desired but it is preferable that they'be in place for the fifty-five ,ton carl and cer- `t`ainly present for ythe seventy. tonv equipment. In yforty vton cars` the 'springs are initially held underless than 10,000 pounds compression :whereas for seventy ton cars the pressure is initially greater. However,

'the disclosure fis fmerely Yintended to. be illustrative of the basic scheme."

From" the foregoing description and a study of the drawings it will be'apparent that -I have provided' a very simply constructed spring nestor assembly which'may be used to replace the ordinary designs .and which may be mounted' in identically Y the same manner, the only difference being thefpro'vision of the holes inthe bolster and the spring seat'for the accommodation ofthe' snub boltsr Such holes may befbored inalready existing equipment without any great amount ofv labor so that the cost of in'stallationwill be but slight. Adequate provision has lbeen made'for cush ioning the strains upon the snub bolts so that ythey will not V'be liable to breakage: The

working curve of the spring will be'eifectually brokeny 4as 'clearly indicatedA on the graph so vthat the development of any vertical jiggle to a dangerous extent will ybe" prevented. It

is thought that the construction, operation andv advantages should Vbe 'readily apparent -ios to'one skilled in the'art-without `further ex-l planation.

While I have shown D y and describedfthe preferred embodimentsfof the invention, `ity should be understood thatl the disclosure is merely an exemplification of the principles involved as the `right lis reserved to make all suchchanges in the details of construction as will widen thelieldyof utility and increase the. adaptability of the device provided such changes constitute no departure from the spirit of the invention or the scopeof the claims hereunto appended.

Having `thus described the invention, I c1aim:- .l ff

1. A car truck including a side frame having a window opening, a bolster extending into the opening, and aspring assembly within the opening vfor supporting the bolster, said assembly including a-pluralityof units certain of which are operable in sequence with respect tothe others, and means yconnecting thev side frame and the bolster for maintaining the first operating ones of the units under initial compression.

2. A car truck including a sidelframe having awindow opening, a bolster extending into the opening, and a spring assembly Within the opening for supporting the bolster, said assembly comprising arplurality of units certain of which are yadapted to become energized subsequently-to the others, and means connected with the side frame for maintaining the others of the units under initial compression. c 1 Y 3. A car truck including a side frame having a window opening,- a bolster extending into the opening, a spring assembly within the opening for supporting thel bolster, said assembly comprising a group of units .bearing againsty the underside of the bolster and a group spaced below the bolster, and means connected with the side frameA for maintaining the first named group of units under initial compression.

4. c A car truck including aside frame havinga window opening, a bolster extending into the opening, and a spring assembly Within the opening lfor supporting lthe bolster, said assemblycomprising a plurality of coil springs of A. R. A. standard height bearing against the underside of the bolster and other springs of less height, and means connected with the bolster for maintaining the first named springs under initial compression.

5. A cartruck includinga side frame harving a-window opening, a bolster extending intothe opening, an a .spring assembly within the opening for supporting the bolster, said assembly comprising a plurality of coil springsl certainl of which are of standard height and `the others of less height, and means connected with the bolster and the side frame f for vmaintaining the standard height springs under Vinitial compression. c

6. A car truck including a side frame having a window opening, a bolster extending into the opening, and a spring assembly within the opening for supporting the bolster,

said assembly comprising a group of coil springs of standard height enclosing other springs, and a group of separate springs of less unrestricted height, means connecting the bolster and the side frame for maintaining the first named group under predetermined initial compression, and'niea'ns for cushioning said connecting means.

7. car truck including aside frame having a Window opening, a bolstereXt-ending into the opening, and a spring assembly within the openingi'or supporting the bolster, said assembly ,comprising a pluralityl of coil springs, means connecting the bolster and the side frame for maintaining certain of the coils unjderl predetermined initial compression.an d means `for cushioning said connecting means located within the bolster.`

8. A car truck'including a side frame having a window opening, a bolster extending into the opening, anda l'spring assembly withinthe opening for supporting the bolster, said assembly 'comprising 'a plurality of coil springs of standard free height and a group of less free height', means connecting the bolster and the side frame for maintaining the first named springs under predetermined initial compression, and means for cushioning said connecting means located within the bolster and operating upon recoil of the assembly to relieve the strain on said connecting means.

9. A car truck including a side frame having a Window opening, a bolster 'extending into the opening, and a spring assembly Withinthe openingfor supporting the bolster, said assembly comprising a plurality of coil springs, means vconnecting the bolster and the side frame for applyinginitial compres'- sive force upon .certain of the springs', and

means for restraining'said connecting means against movement with respect'to the bolster.

`10. A car'truck including a side frame having a window opening, bolsterexten'ding into the opening, and a spring assembly Wit-hin the opening for supporting the bolster, said assembly comprising a plurality of coil springs, and means connected with the bolster and slidably connected with the side frame for maintaining certain 'of the springs under initialcompression.

y11. A ca r truck including aside frame having a fwindow opening, a bolster extending into the opening, and a spring assembly within the opening for supportlng the bolster, said assembly comprising a'plurality of units of standard height and a plurality of shorter units. and bolt means connecting the bolster and the side frame for maintainingthe rfirst units under initial compressionwhile unaffecting the shorter units.

12. A car truck including a side frame -having a Window opening, a bolster extending into the opening,'and aspring vassembly Within the opening for supportingy the boliso ster, said assembly comprising a plurality of units of standard height and others of less height, 'bolt means connecting the bolster and the side frame for maintaining the first named units under initial compression with the nuits of less height unconlined, and

cushioning means reacting against the bolt means and the bolster.

1:3. A car 'truck including a side'frame ha ving a window opening, a bolster extending into the opening. and a spring assembly Within the opening for supporting the bolster, said assembly comprising a plurality of units, bolt means connecting the bolster and the side frame for maintaining certain of the units under initial compression, and cushioning means reacting against the bolt means and the bolster and located Within the latter.

14. A car truck including a side frame having a Window opening, a bolster extending into the opening. and a spring assembly within the opening for supporting the bolster, said assembly comprising a. plurality of coils springs, bolt members connecting the bolster and the side Jframe and movable with respect to the latter, said bolt members maintaining certain of the coil springs under initial compression, and means for cushioning said bolt members.

15. A car truck including a side frame having a Window opening, a bolster extending into the opening. and a spring assembly within the opening for supporting the bolster. said assembly comprising a plurality of coil springs, bolt members connecting the bolster and the side frame and movable With respect to the latter, said bolt members maintaining certain of the coil springs under initial compression, means for cushioning said bolt members, and means for preventing rotation of the bolt members.

16. A car truck including a side frame having a. Window opening, a bolster extending into the opening, and a. spring assembly Within the opening for supporting the blster, said assembly comprising a plurality of coil springs, bolt members connecting the bolster and the side frame and movable with respect to the latter, said bolt members maintaining certain of the coil springs under initial compression, means for cushioning said bolt members, and means carried by the bolster and located therewithin for preventing rotation of the bolt members.

17. A car truck including a side frame having a window opening, a bolster extending into the opening, and a spring assembly Within the opening for supporting the bolster, said assembly comprising a pluralityof coil springs, bolt members connecting the bolster and side frame and passing through the assembly for maintaining certain of the coil springs under preliminary compression, means within the bolster reacting against said bolt members for cushioning the same on recoil, and means within the bolster for preventing rotation of the bolt members.

18. A car truck including a side frame having a. Window, a bolster extending into THOMAS H. SYMINGTON.

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