US2996021A

US2996021A - Railway cars for transporting freight carriers

Info

Publication number: US2996021A
Application number: US789596A
Authority: US
Inventors: Clejan Deodat
Original assignee: General American Transportation Corp
Current assignee: General American Transportation Corp
Priority date: 1959-01-28
Filing date: 1959-01-28
Publication date: 1961-08-15
Anticipated expiration: 1978-08-15

Description

D. CLEJ AN Aug. 15, 1961 RAILWAY CARS FOR TRANSPORTING FREIGHT CARRIERS Filed Jan. 28, 1959 4 Sheets--SheeI l IN VEN TOR. Deoda Ole/'an Aus 15, 1961 D. CLEJAN 2,996,021

RAILWAY CARS FOR TRANSPORTING FREIGHT CARRIERS Filed Jan. 28, 1959' 4 Sheets-Sheet. 2

IN VEN TOR.

w10@ Am/s.

D. CLEJAN Aug. 15, 1961 RAILWAY CARS FOR TRANSPORTING FREIGHT CARRIERS Filed Jan. 28 1959 4 Sheets-Sheet 3 JNVENTOR Deoda Cle/'an Anya D. CLEJAN Aug. 15, 1961 RAILWAY CARS FOR TRANSPORTING FREIGHT CARRIERS Filed Jan. 28, 1959 4 Sheets-Sheet 4 INVENTOR.

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BY Deoa Clejan @114W @aal (147W, j l j 070e, lm/5.

2,996,021 RAILWAY CARS FOR TRANSPORTING FREIGHT CARRIERS p Deodat Clejan, Chicago, lll., a'ssignor to General Amencan Transportation Corporation, Chicago, Ill., a corporation of New York. Filed Jam 2,8, 1959, Ser. No. 789,596

1 Claim. (Cl. 10S- 368) 'Ille present invention relates to a transportation system comprising a railway car and a removable freight carrier therefor, and more particularly to a latchable clamp assembly for such railway car releasably to anchor the freight carrier thereto.

A transportation system of this general type including a clamp assembly for the railway car thereof is disclosed in the copending application of Deodat Clejan, Serial No. 593,848, filed June 26, 1956, now Patent lNo. 2,944,492 dated July 12, 19760; and the present application constitutes an improvement with respect to the prior application noted.

In this prior application, the disclosed railway car is of skeleton form and has a longitudinally extending, hollow center sill supported at each end thereof by respective wheel-equipped trucks that ride along the rails of a main railroad track. Provided along the top of this hollow center Vsill is a pair of spaced-apart rails that define an auxiliary track adapted to support a plurality of rollers thereon Iwith which such freight carrier is equipped and to thereby 'support the freight carrier. The freight carrier is rolled longitudinally along the auxiliary track to load the freight carrier onto and unload the same from the railway car; and the hold-down or clamping arrangement is required to secure or anchor ,the freight carrier to the railway car during movement of the latter. The clamping arrangement disclosed in the prior application is operative -between the center sill of the railway car and under-structure of the freight carrier, and includes cushioning mechanism which permits limited longitudinal movements of the freight carrier relative to the railway car while resiliently resisting such movements. Since the freight carrier and its lading are quite heavy and move with respect to the railway car especially during starting and braking thereof, and since the substantial inertial forces resulting therefrom are imposed on the clamp assembly and cushioning mechanism thereof, a positive latching device effective to prevent inadvertent release of the clamp assembly is advantageously included as a component of the railway car; and the provision of such a latching device is one of the objects of this invention.

Another object of the invention is in the provision of a latching device selectively operable between an active latched position and an inactive unlatched position, when the clamp assembly is in engagement with a freight carrier to anchor the same to the railway car, and effective in its active position to prevent release of the clamp assembly, but ineffective in its inactive position to prevent release of the clamp assembly.

Still another object is in the provision of a latching device that is normally maintained by the forces of gravity acting thereon in a position such that it is conditioned to automatically latch the clamp assembly in the hold-down position thereof so as to prevent accidental release of the clamp assembly after movement thereof into engagement with a freight carrier to anchor the same to the railway car.

Yet a further object is that of providing in a railway car equipped with a center sill having an auxiliary track to receive and support a roller-equipped freight carrier thereon and having also laterally spaced shafts respectively connected thereto by cushioning equipment that nited States Patent `2,996,021 Patented Aug. 15, 1961 affords limited longitudinal movements of the shafts and also affords rotational movements of the shafts to selectively move clamping members carried thereby into positions of engagement and disengagement with the freight carrier, as positions respectively corresponding to such positions are enforced on the shafts by the angular position of a rotatable transverse shaft operatively connected therewith: a latching device including a gravity controlled lever equipped with a visual signal at an end thereof which is automatically retracted into an inconspicuous position by movement of the latching device into its inactive position in response to disengagement of the clamp members from the freight carrier by angular movement of the rotatable shaft in one direction about the axis thereof, and which is automatically extended into a conspicuous position by movement of the latching device into its active position in response to engagement of the clamp members with the freight carrier by angular movement of the rotatable shaft in the opposite direction about the axis thereof; and in which the lever, when the latching device is in the active position thereof, may be positively engaged by a latch dog carried by the rotatable shaft to constrain angular movement thereof in a direction which would effect disengagement of the clamping members from the freight carrier.

Additional objects and advantages of the invention will become apparent as the specification develops.

An embodiment of the invention is illustrated in the accompanying drawings, in which- FIGURE 1 is a broken side view in elevation of a railway car embodying the invention and which has a plurality of freight carriers mounted thereon, a portion of the center sill of the railway car being broken away to reveal a structural detail thereof;

FIGURE 2 is an enlarged, broken vertical sectional view taken along the line 2--2 of FIGURE 1;

FIGURE 3 is an enlarged, broken top plan View of the railway car shown in FIGURES l and 2, and in which portions of the center sill are broken away to illustrate more clearly certain features of the clamp assembly;

FIGURE 4 is an enlarged, broken longitudinal sectional yiew taken along the line 4 4 of FIGURE 3;

FIGURE 5 is a transverse sectional view taken along the line 5-5 of FIGURE 3, and shows the clamp assembly in the release or retracted position thereof;

FIGURE 6 is a transverse sectional view generally similar to that of FIGURE 5, but taken along the line 6-6 of FIGURE 3 and showing the clamp assembly in the carrier-engaging position thereof;

FIGURE 7 is `a broken longitudinal sectional View taken along the line 7-7 of FIGURE 3;

FIGURE 8A is an enlarged, fragmentary View of the right-hand portion of FIGURE 5 illustrating details of the latching device with greater clarity and the inactive position thereof;

FIGURE 8B is an enlarged, fragmentary view corresponding essentially with the right-hand portion of FIGURE 6, and illustrating in detail the latching device in the active position thereof; and

FIGURE 9 is a still further enlarged, broken vertical sectional view taken -along the line 9 9 of FIGURE 8B.

As stated hereinbefore, a detailed description of the transportation system illustrated in FIGURE 1, and of the clamp assembly which is utilized to anchor the freight carrier to the center sill of a railway car, is set forth in my copending application, Serial No. 593,848, identified hereinbefore, `and reference may be made thereto for a complete consideration of the system and clamp assembly, However, for purposes of convenience, the system in its entirety will be described briefly herein together with a somewhat more extensive discussion of the clamp as- Ysembly because of its intimate relation to the latching having wheels 14 that ride along the rails 15 of a main n railroad track. The two freight carriers illustrated in 'position upon the railway car 10 are each denoted with the numeral 16 since they are identical, and are shown in an exemplary form thereof as a road vehicle; and specifically, a semi-trailer having the usual running gear 17 at the rear end thereof providing tire-equipped wheels 18, having also a king pin 19 at the forward end thereof Yadapted to interlockingly engage the fifth wheel of a tractor, and having additionally an intermediate landing gear 20 adjacent its forward end portion.

Considering the railway car and freight carrier in greater detail, with particular reference to FIGURE 2, lit will be seen that the longitudinally extending, hollow center sill 11 comprises a pair of parallel, longitudinally spaced I-

beams

21 and 22 rigidly secured at longitudinally spaced intervals therealong to transoms in the form of transversely extending I-beams 23. The upper or top .ange of the respective longitudinal I-

beams

21 and 22 vprovide

rails

25 and 26 that define-an auxiliary track adapted to support each of the freight carriers 16 thereon. To effect such support, each freight carrier is equipped with anged rollers 27 arranged in pairs, each .pair being mounted for rotation on a dolly casting or mounting structure 28 rigidly secured to the running gear of the freight carrier. It will be evident that rollers 27 are -required for each of the

rails

25 and 26, and therefore at least one dolly is provided on each side of the freight carrier. In the specic embodiment shown, each freight carrier 16 is a two-axle semi-trailer, and each axle at the respective ends thereof is equipped with a dolly, making a total of four such dolles. Each pair of rollers 127 is located inside of the circle defined by the circumfferential surface of the tire-equipped trailer wheel asso- `ciated therewith so that the lrollers do not interfere with movement of the freight carrier along a highway.

VNecessarily, means must be provided to secure the freight carriers to the railway car so as to prevent displacement of the freight carriers therefrom. However,

-railway cars are repeatedly subjected to rapidly changing forces directed along the longitudinal axis thereof which Yresult from accelerations and decelerations, and since such forces are often large and are in the nature of irnpact forces, it is undesirable to have the same imparted VVnally extending shafts 31 is effected by a transverse shaft directly to a freight'carn'er for in many cases such direct application of the forces thereto and, consequently, Vthe lading therein would be completely ruinous to the latter. Therefore, the latch assembly employed to anchor the freight carrier to the car is `of such character that it permits limited longitudinal movement of the freight carrier will be used to identify the components of each except that the numerals will be primed when applied -to the unit associated with the beam 21. Each unit hasY an outer casing 29 riveted or otherwise rigidly secured to the Aweb of the center sill beam associated therewith, and mounted within the casing is a shock absorber 30 Vsecured at one end to a longitudinally extending shaft 31 which is supported both for rotation about" itsown axis and for longitudinal sliding movements by a bearing 32 provided at an end of the vcasing 29. Each of the longitudinally extending shafts 31 is equipped with a holddown hook or clamp 33 constrained on the shaft so as to both rotate and move Ylongitudinally therewith. Such mounting can be accomplished by split collar and tightening bolt arrangements orby any other suitable means. Rotation of the Ylongitudinally extending, laterally VAspaced shafts 31` is effective to move the respective hold-down hooks 33 ybetween a,retractedreleaseposition, wherein they are disposed belowthe upper edge of the auxiliary track defined by the rails -25 and 26 (as shown in lFIG- URE 5), and an extended clamping position as illus- ,trated in FIGURE 6, wherein the end portions of the A spective dolles 28 which comprise a part of Ithe understructure, of each of the freight carriers 16. The openings 34 are elongated in the longitudinal direction, as

'shown in FIGURE 4, Yto'permit the insertion of the hooks thereinto without the necessity of precisely locating the freight carrier longitudinally along the railway car and 'center sill thereof.

It Iwill be evident that the individual shafts 31 must be rotated in opposite directions relative to each other to yswingV the hooks 33 int-o their respective clamp and `release positions. Thus, in FIGURES 5 and 6, the shaft 31 shown in the left-hand portion of these figures must be rotated in a counterclockwise direction at the same time that the shaft 31 in the right-hand section ofthese gures is rotated in a clockwise direction, to swing the respective clamps 31' and 31 from the retracted position of FIGURE 5 to the clamping position of FIG- URE 6, and vice versa. Rotation of the 4longitudior operating screw 35 having oppositely threaded end `portions 36 and 37 individually associated with the re- -

spective gimbais

38 and 38 which in turn are connected 40' to the

respective shafts

31 and 31 hy bifurcated

lever arms

39 and 39 made rigid with the shaft therefor by

split collar arrangements

40 and 40 drawn tightly thereon by nut-equipped bolts 41- and 41', as Vis shown most `clearly -in FIGURE 7. As a consequence of this mounting, the respective lever arms 39 must rotate and also move longitudinally with the respective shafts 31; and ',necessarily then, the'screw 35 must be free to move in longitudinal directions with respect to thecenter sill and,

-las has been stated, must be rotatable relative thereto. Further, for reasons to Abe described subsequently, the

operating screw 35 must also be free to move in vertical directions withV respect to the center sill.

The operating screw 35 is lequipped at each end thereof A.with an enlarged head, denoted 42 and 42 for differentiation therebetween, and such heads define stops that limit outward movement of the respective gimbals 38. The operating screw 35 is also equipped with a tubular spacer 43 located in the centralrportion thereof which defines a ,stop that limits inward travel of the respective gimbals 38. The operating screw at each end thereof (see FIG- URES 8A and 8B) has a socket 44 adapted to seat the end of a crank (not shown) therein which is used to rotate the operating screw to swing the hooks 33 between @the hold-down and release positions thereof. To accommodate such crank, the webs of the center sill beams 21 and 22 are each provided with an opening 45 therethrough which affords -access to the respective sockets 44.

It will be noted (FIGURE l) that the openings 45 are elongated in the vertical direction which is required to permit the crank to be inserted into the sockets 44 irrespetiveA of the vertical position of the operating screw 35. The gimbals are operative to permit Vcompound pivotal movements of the respective lever arms 39 and 39'- horizontal and vertical axes taken through the operating screw 35. To permit such movements, each of the gimbals comprises a trunnion block or nut 46 (see FIGURE 7) threadedly mounted on the end portion associated therewith of the operating screw 35, and the nut is equipped with vertically extending, axially aligned pivot pins 47 and 48 that are pivotally received by the top and bottom sections of a trunnion yoke 49 that extends perimetrically about the nut 46 in one plane thereof. Therefore, the pivotal vaxis of the trunnion yoke about the nut 46 is oriented in the vertical direction and extends substantially through the center of the operating screw. The -trunnion yoke in turn is equipped with a pair of axially aligned pivot pins 50 and 51 that are pivotally received by the respective legs or sections of the bifurcated lever arm 39 arranged therewith. The axis defined by the pivot pins 50 and 51 extends substantially through the center of the operating screw 35, and is oriented longitudinally with respect to the center sill v11.

With this construction, rotation of the -operating screw in a direction which enforces movement of the hooks 33 .into the hold-down position thereof causes the respective gimbals 38 to move inwardly along the Voperating screw and toward abutment 'with the spacer 43, as shown in FIGURE 6. This movement of the gimbals causes the lower end portion of the respective lever arms 39 to` swing inwardly and upwardly whereby the longitudinally extending shafts 31 are rotated. However, such movement of the lever arms 39 tends to shorten the distance between the longitudinally extending shafts 31 and the operating screw 35; and as a consequence thereof, the operating screw is elevated from the lower position thereof shown in FIGURE and into the upper position illustrated in FIGURE 6. Rotation of the operating screw in the opposite direction to retract the hooks 33 returns the operating screw to its initial lower position.

As stated hereinbefore, it is desired to provide a latch- Ving dev-ice automatically operative to latch .the clamp assembly in the position illustrated in FIGURE 6, wherein the hold-down hooks 33 thereof are in engagement with the cooperating understructure of a freight carrier to anchor the same to the railway car. Also, it is desired to provide visual signal means responsive to the latching device to indicate to the appropriate personnel that the clamp assembly is connected with a freight carrier, and that the latching device is in its active position. The latching device and signal means are illustrated most 'clearly in FIGURES 8A, 8B and 9, and in describing these features in detail, reference will be made to these figures.

At least one of the gimbals in each clamp assembly (the gimbal 38 in the drawings) has a support rod 52 welded or otherwise rigidly secured thereto, and this support rod extends along the operating screw 35 in spaced, parallel relation therewith. Pivotally mounted on the support rod 52 adjacent the inner end thereof is a latch member or ratchet lever 53. The latch member 53 has an opening therein through which the support rod 52 extends, and the axial position of the latch member along the support rod is determined -by cotter pins 54 and 55 which extend through apertures therefor provided in the support rod, and which are separated from the respective sides of the latch member by

washers

56 and 57. It will be apparent that other appropriate locating arrangements may be employed to secure the latch member on the support rod in a manner that permits free rotation of the latch member about the longitudinal axis of the support rod, while constraining the latch member against substantial axial movement along the rod.

The length of the support rod 52, and more particularly the axial position of the latch member 53 therealong, is determined so that the latch member is disposed at substantially the center of the spacer 43 when the gimbal 38 is in abutment therewith. The reason for this dimension-al relationship in the specific structural embodiment of the invention considered herein is that the spacer 43 is 6 equipped at substantially the center thereof with a latch dog 58 adapted to interlockingly engage a latch recess 59 provided by the latch member 53; Iand -because of the central location of the latch dog, the latch member 53 must be disposed at the center of the spacer 43 in order to align with the latch dog and latch recess 59 thereof when the gimbal is in substantial abutment with the spacer, which position of the gimbal corresponds to the position of the hold-down hooks 33 when -in clamping engagement with a freight carrier. 'I'he latch dog 58 has an edge portion thereof spaced slightly from the circumferential surface of the spacer 43, and such edge portion defines a tongue insertable into the latch recess 59 when the foregoing alignment is established.

By referring again to FIGURE 9, it will be noted that the latch member 53 has substantially all of its m-ass disposed :to the left `of the pivotal -axis therefor dened by the support rod 52, and therefore the latch member is gravity or weight biased in a counter-clockwise direction as viewed in this Iligure. As a consequence, the latch 59 of the latch member 53 tends to :ride on the circumferential surface of the Spacer 43 unless the latch member is manually rotated in a clockwise direction, and is thereafter held in such position so as to space the latch 59 outwardly from the surface of the spacer. In order to limit pivotal movement of the latch member 53 in either direction about the support rod 52, stop means are provided in the form of a keeper pin 60 'rigidly secured at one end thereof to the support rod, and which has a free end portion that extends axially along the support rod in spaced relation therewith.

The keeper pin 60 extends through an enlarged opening 61 provided therefor in the latch mem'ber 53; and since the `diameter of the opening 61 is much larger than the diameter of the keeper pin 60, a limited range of movement is aiforded for the latch member. However, the keeper pin 60 limits movement of the latch member 53 in the counter-clockwise direction (FIGURE 9) to a Vlocation such that the latch-equipped end thereof just clears the circumferential surface of thel spacer 43, whereby movement of the latch member axially along the operating screw 35 toward the spacer 43, from right to left as `seen in FIGURES 8A and 8B, when the operating screw is rotated in a direction to move the gimbal 38 inwardly, is not impeded or restrained by Iabutment of the latch member with the end of the spacer. If desired, the spacer 43 may have -a slight taper or frusta-conical configuration at the end thereof traversed by the latch member 53 so that such end will operate to cam the recessed end of the latch member outwardly and onto the circumferential surface of the spacer and thereby compensate for any inaccuracies in the location or diameter of the keeper pin 60 or in the location or diameter of the opening 61 in the latch member. The limits of rotation of the latch member 53 in the oppositedirection--- that is, in a clockwise direction as seen in FIGUREA 9 rare not so critical, but should be such that the center of gravity of the latch member is always disposed to the left of thesupport -rod 52, whereby the weight of the latch member will always bias the s-ame into an active position wherein the latch recess 59 thereof will be properly oriented for engagement with the latch dog 58.

Rotation of the operating screw 35 to move the holddown hooks 33 into clamping engagement with a freight carrier 16 is in a clockwise direction as the screw is viewed in FIGURE 9, whereby during such rotation, the latch dog 58 moves freely under -the latch ymember 53 and simply cams the latch-equipped end 59 thereof outwardly each time the latch dog engages that end. Follow-ing such rotation to position the hold-down lhooks 33 in clamping engagement with the freight carrier v1.6, the operating screw 35 is rotated slightly in a counter-clockwise direction to insert the latch dog 58 into the latch recess 59, with the result that further rotation of the operation screw Ain thecounter-clockwise direction is positively preventedy bythe interlock thusly established between the latch member Iand latch dog. Y I

VIn order to release the latch member 53 preparatory to retracting the hold-down hooks 33, the operating screw 35 must be rotated slightly in a clockwise direction, as seen in FIGURE 9, to Withdrawthe latch dog 58 from the latch recess 59. Thereafter, the latch member 53.can be manually pivoted about the support rod 52 into the position shown by broken lines in FIGURE 9, to space the latch recess 59 from the circumferential surface of the spacer 43 by a distance sufficient to permit the operating screw 35 to be rotatedin ya counter-clockwise direction without the latch dog 58 engaging the latch 59. As soon as the gimbal 38 and latch member 53 have been moved axially along the operating 'screw 35 a distance ysuicient to space the latch member from the latch dog 58, Vthe latch member can be released and will not interfere with further rotation of the operating screw. Preferably, the ends of the Ilatch dog 58 are tapered slightly and merge smoothly into the surface of the spacer 43 so that the latch member 53 can ride freely thereover when moving toward the center of the spacer.

As previously noted, the operating screw 35 shifts vertically with respect to the center sill when the holddown hooks 33 and 33 are moved between the retracted, release position and extended, clamping position thereof.

.This movement of the operating screw is evident by a comparison of FIGURES and 6 or FIGURES 8A and 8B, and occurs because the lever arms 39 and 39' describe arcuate paths in moving about the respective axes of the

longitudinal shafts

31 and 31 when the hold-down hooks vare moved between the clamp and release positions thereof 'and because the operating screw is carried by these lever arms. Specifically, the operating screw is in a lower posi- Vtion when the hold-down hooks are retracted, yand is in v-tions thereof. VAs a result, the upper end portion of the latch member 53 is raised to a position above the auxiliary track delined by the

rails

25 and 26 when the operating screw-35 is in its elevated position, which corresponds to the clamping position of the hold-down hooks 33 and 33 and which corresponds also to the active position of the latching device, as is evident in FIGURES 6 and 8B. On .the other-hand, the upper end portion of the ylatch member'53 is retracted below the auxiliary track when the operating screw is in its lowered position corresponding Yto the release position of the hold-down hooks 33 and 33', and corresponding also to the inactive position of the 4latching device. the lactive position of the latching device and clamping Thus, `a visual signal indicative of both position of the hold-down hooks and responsive thereto, is provided by marking the upper end portion of the latch member 53 with readily visible indicia, as shown at 62 in FIGURE 8B. Such indicia may be, for example, red or yellow paint applied to the end portion of the latching member. Thus, such visual signal is operative in response to the position of the latching'device for the signal is `moved into a conspicuous position above the auxiliary track when the latching device is in the active position thereof, and is retracted into an inconspicuous position below the auxiliary track when the latching device is in its inactive position.

Thus, in the transportation system described which includes a railway car and removable freight carrier therefor and aclamp assembly for selectively anchoring the. freight carrier to the railway car, a latching device has been provided whichis operative to selectively latch the clamp kassembly in engagement with the freightrcar- Vrier and thereby prevent inadvertent release of the clamp assembly. Further, visual signal means are incorporated 8 into the system, and are responsive to the position of the latching device and clamp assembly soas to provide signals respectively indicative of theactive and inactive positions of the latching device and therefore of the clamp and release positions of the clamp assemblywhich, respectively, correspond to the active and inactive positions of the latching device. Y Y v While in the foregoing specification an embodiment of the invention has been set forth in considerable detail for purposes of making a complete disclosure thereof, it will be `apparent to those skilled in the art that numerous changes may be made in those details without departing from the spirit and principles of the invention.

What is claimed is:

A railway comprising a longitudinally extending hollow center sil-l, a pair of trucks supporting the opposite ends of said center sill and each carrying main track wheels, said center sill being substantially narrower than said trucks so that the opposite sides thereof are disposed well inwardly with respect to said main track wheels, a pair of longitudinally extending and laterally spaced-apart rails respectively located adjacent to the opposite sides of said center sill along the top thereof and constituting an auxiliary track adapted to engage and to supportrthereon cooperating rollers carried by a freight carrier removably associated with said railway oar so as to accommodate mounting of said freight carrier upon said center sill, a pair of longitudinally extending and laterally spaced-apart shafts supported by said center sill for both rotational and longitudinal sliding movements with respect thereto, a pair of attachments respectively carried iby said shafts for rotation therewith between active and inactive positions, said attachments in their active positions being disposed yabove the top of said center sill for engagement and connection with the opposite undersides of such freight carrierrmounted upon said center sill and said -attachments in their inactive posi- -tions being disposed below the top of said center sill for disengagement and disconnection from the opposite undersides of such freight carrier mounted upon said center sill, a pair of actuating mechanisms respectively carried by said shafts for longitudinal movements therewith, a transversely extending operating screw rotatably supported jointly by said actuating mechanisms and independently of said center sill, rotation of said operating screw in one direction effecting first related axial movements therealong of said actuating mechanisms and rotation of said operating screw in the other direction efecting second related axial movements therealong of said actuating mechanisms, said lirst related movements of said actuating mechanisms simultaneously rotating said shafts in lirst related directions so as to rot-ate said attachments into their active positions and said Second related movements of said actuating mechanisms simultaneously rotating said shafts in second related direction so as to rotate said attachments into their inactive positions, latching mechanism including first and second latch parts respectively carried by one of said actuating mechanisms and by said operating screw, whereby said first latch part is movable axially along said operating screw and said second latch part has a lixed axial location along said operating screw, said lirst latch part being moved into cooperating relation -with said second latch part in response to said first related movements' of said actuating mechanisms to rotate said attachments into their active positions and said rst latch part being moved out of cooperating relation with said second latch part in response to said second related movements of said actuating mechanisms to rotate said attachments into their inactive positions, said latching mechanism also including means for selectively engaging and disengaging said latch parts only when said rst latch part is in cooperating relation with ysaid second latch part, and two-way cushioning mechanism connecting said shafts and said center sill, so as to resist Iand to cushion longitudinal sliding movements of said shafts and thus fore-and-aft rolling movements /of References Cited in the file of this patent UNITED STATES PATENTS Brennan Nov. 10, 1908 10 Bellingrath Sept. 12, 1911 Stecker Ian. 1, 19118 Raney Jan. 21, 1919 Campbell Jan. 3, 1933 Earll Jan. 2, 1934 Turner May 8, 1951 Luke June 17, 1958 Patent Nm7 9969021 I corrected below.

UNITED STATES PATENT. OFFICE b ACERTIFIGATE 0F CORRECT-1oNl August l5Q 1961 in bhe above numbered patlt s hereby certified that error appears ters Patent should read as etat4 requiring correction and that the said Let Column 85 line l5'v after "railway" insert car signed and sealed this 3rd day of April 1962;.

- (SEAL) Attest:

ERNEST W. swIDER DAVID L LADD Ausgang offir Y Commissioner .of Patents