US3410131A

US3410131A - Test fixture for hydraulic cushion device

Info

Publication number: US3410131A
Application number: US611154A
Authority: US
Inventors: Thomas L Roesel
Original assignee: Pullman Inc
Current assignee: Pullman Standard Inc; Pullman Inc
Priority date: 1967-01-23
Filing date: 1967-01-23
Publication date: 1968-11-12
Anticipated expiration: 1985-11-12

Description

Nov. 12, 1968 T. 1.. ROESEL TEST FIXTURE FOR HYDRAULIC CUSHION DEVICE 4 Sheets-Sheet 1 g V mm wm S 1 *5 S 8 mm mm E E m 2w f 4 mm 1 x m 1 r/ T L LL; m mm milLrllFlw K f alli- Filed Jan. 23, 1967 INVENTOR I THOMAS L. ROESEL ayfw x? W) ATT'Y Nov. 12, 1968 T. ROESEL TEST FIXTURE FOR HYDRAUL IC CUSHION DEVICE 4 Sheets-Sheet 2 INVENTOR vw mw mm mm Filed Jan. 23, 1967 THOMAS L. ROESEL ATT'Y.

T. L. ROESEL TEST FIXTURE FOR HYDRAULIC CUSHION DEVICE Nov. 12, 1968 Filed Jan. 2s, 1967 4 Sheets-Sheet IN VENTOR THOMAS L. ROESEL ATT'Y.

Nov. 12, 1968 T. 1.. ROESEL TEST FIXTURE FOR HYDRAULIC CUSHION DEVICE 4 Sheets-Sheet 4 Filed Jan. 23, 1967 INVENTOR THOMAS L. ROESEL ATT'Y.

United States Patent 3,410,131 TEST FIXTURE FOR HYDRAULIC CUSHION DEVICE Thomas L. Roesel, Lansing, Ill., assignor to Pullman Incorporated, Chicago, Ill., a corporation of Delaware Filed Jan. 23, 1967, Ser. No. 611,154 3 Claims. (Cl. 73-11) ABSTRACT OF THE DISCLOSURE A text fixture for testing operation of an extendable and contractable hydraulic cushioning unit of the type disclosed in US. Patent 3,003,436 which is used in cushion underframe railway vehicles to minimize lading damage. The test fixture includes means for moving the cushion unit against a stop from an extended to a contracted position and for releasing the stop so that a return spring of the cushion device is operative to return the device to the extended position.

Summary of the invention The cushion device or unit of the type to be tested by the test fixture of the present invention includes a hydraulic fluid filled cylinder in which there is mounted for reciprocation fluid displacement means in the form of a piston assembly. The cushion unit is adapted to be disposed for inter-action between the underframe and sliding sil'l of a cushion underframe railway vehicle. Upon impact to the couplers carried by the sliding sill, the cushion unit travels from an extended position to a contracted position during which travel a portion of the impact of energy is absorbed or dissipated to provide lading protection to the lading carried on the railway vehicle. After the impact has been dissipated a return spring disposed between the piston assembly and the hydraulic fluid filled assembly is operative to return the components of the unit to the extended position.

The cushion test fixture of the present invention is arranged to receive the cushion unit in its extended position. Means are provided for contracting the cushion unit components from their extended to a contracted position to simulate to some extent the condition occurring in the railway car in which it is adapted to be installed. To check the functioning of the cushion unit under its severest conditions there is provided a means on the test fixture for contracting the cushion and thereafter releasing the cushion components from the latter position. The means for releasing the cushion are required to be constructed and arranged to achieve a rapid release so that the spring of the cushion unit is operative to return the components to the original extended position as rapidly as possible. Under these conditions of test there is simulated as closely as possible the condition occurring when the sliding sill is bound within the stationary sill and thereby holding the cushion unit in contracted position until the binding cause is overcome and the return spring is operative to rapidly return the components to the original extended position. During such rapid return severe stresses are imposed on the various components of the cushioning device and at the same time extreme hydraulic flow conditions occur within the hydraulic unit which also may create a problem area in connection with a flexible boot reservoir associated with the cushion unit.

Description of the invention In the drawings:

FIG. 1 is a fragmentary top plan view of the test fixture embodying the principles of the present invention with some of the parts broken away to show underlying details of structure and the position.

3,410,131 Patented Nov. 12, 1968 FIG. 2 is a side elevational view of the cushion test taken generally along the lines 22 of FIG. 1.

FIG. 3 is a fragmentary top plan view of the cushion test fixture with the cover removed and showing the cushion unit disposed therein with the components thereof positioned after the fixture stop has been released.

FIG. 4 is a cross sectional view taken generally along the lines 4-4 of FIG. 1.

FIG. 5 is a cross sectional view taken generally along the lines 5-5 of FIG. 1.

FIG. 6 is a perspective view partially in section shoW- ing the cushioning device adapted to be tested in the text fixture illustrated in FIGS. 1 to 5 and showing the components of the cushioning device in their extended position, and

FIG. 7 is a view similar to FIG. 6 but showing the components of the cushioning device in the contracted position.

Referring now to the drawings, in particular FIGS. 6 and 7 there is shown the cushioning device or unit C adapted to be tested in the test fixture 10 illustrated in FIGS. 1 to 5. The cushioning device is of the type as heretofore mentioned which is used in cushion underframe railway vehicles for minimizing the lading damage carried on the railway vehicle. The cushioning device comprises generally a hydraulic filled cylinder 11 in which there is reciprocally disposed for relative travel a piston head assembly 12 which is operative to displace fluid from one side of a piston head 13 to the other side thereof. Connecting a piston rod 14 to an intermediate cylinder head 16 mounted in the cylinder 11 is a flexible boot 17 which receives the hydraulic fluid displaced by the piston rod during movement of the piston head assembly 12 from the extended contracted position as shown in FIGS. 6 and 7 respectively. The flow of the hydraulic fluid is metered from one side of the piston head 13 to the other by means of a metering pin 18 which extends through an orifice 19 provided in the piston head 13 and into the bore 21 of the hollow piston rod 14.

During relative movement of the piston head assembly 12 and the cylinder 11, fluid is displaced from a chamber 23 to a chamber 24 by way of the metered orifice 19 to impart a substantially constant force travel characteristics to the cushion unit C. Movement of the cylinder 11 and piston assembly 12 continues until the device reaches its fully contracted position as shown in FIG. 7. After the impact causing the relative movement has been dissipated a spring 26 disposed between a base plate 27 fixed to the cylinder 11 and a base plate 28 fixed to the end of the piston rod 22 is operative to return the unit C back to its neutral or extended position. During the contraction the hydraulic fluid is also introduced into the flexible boot 17 by way of an opening 29 provided in the intermediate cylinder head 16 through which the piston rod 22 extends.

During the travel of the cushioning device C from its extended to its contracted position the hydraulic fluid displaced by the piston rod is introduced into the flexible boot 17 causing the latter to expand. When the cushioning unit returns to its fully extended position the expanded boot 17 forces the fluid to return into the cylinder chambers 24 and 25. However when the return of the cushioning unit is rapid as occurs when a sliding sill is binding to hold the cushioning unit C in its contracted position within the underframe of a railway vehicle and an impact occurs to release the binding condition, the return spring and the force of the impact causes a rapid return. Under these conditions the fluid flow may be such that the boot tends to bulge outwardly under the force of the hydraulic fluid and under some circumstances it may cause the boot to rupture in the event an impact is applied in the opposite direction before the unit C returns to its neutral or extended position.

7 Referring now to FIGS. 1 to 5 illustrating the test flxture the latter comprises generally a base 31 formed by suitable channels and the like. Supported on the base 31 are a pair of transversely spaced channels 32 having upper and

lower flanges

33 and 34, respectively, extending outwardly from side webs 36. Fixed across the bottom flanges 34 is a bottom plate 37 which defines with the side webs 36 an elongated trough 38. Fixed to each of the ends of the trough 37 are channels 39. Spaced inwardly from one end of the fixture 10 is a plate 41 to which there is fixed a clevis 42 to which there is pivotally connected one end of a two way hydraulic piston unit 44, including a cylinder 46 within which there is reciprocably mounted a piston head 47 having connected thereto piston rod 48 extending through the other end of the cylinder 46. The outer end of the piston rod 48 is pivotally connected to a clevis bracket 49 fixed to a base plate retainer means 51 into which one of the base plates 27 of the cushioning device C is adapted to be inserted.

I The base plate retainer means includes a back plate 52 extending transversely of the trough 38 and side plates 53 having inwardly disposed flanges 54 forming a cradle into which the base plate 27 is inserted. The side plates are formed with grooves which receive guide bars 57 fixed to the side webs 36 for guiding the base plate retaining means of lengthwise movement. Lengthwise actuation of the base plate retainer is achieved by actuation of the two way hydraulic cylinder unit 44 by means of a hydraulic motor (not shown).

Spaced inwardly from the end of the plate is a stop arrangement 57 for restraining opposite cushioning device stop plate 28 against a lengthwise movement within the trough 38. The stop arrangement 57 as shown, includes a pair of transversely spaced drum members 5858 each including opposite cylindrical faces 59 and. opposite chord surfaces 61. Each of the drum like members has extending from the upper and lower bases 62 and 63 thereof

shafts

64 and 65 of which the upper shaft 64 is journal d in a top cover plate 66 extending between the upper flanges 33 of the side channels 32. The lower shaft 65 extends through an opening 67 in a bottom plate 68 which is similarly fixed to the lower flanges 34 of the side channels 32. To reinforce the upper and lower plates 66 and 68 there may be provided side plate reinforcing means 69 as shown in particular in FIG. 1.

Connected to the lower ends of each of the shafts 65 are toggle arms 71 of a toggle linkage 72 which is employed to rotate the barrel stop members 58 as more fully to be explained hereinafter. The toggle arms 71 at one end are each connected to the respective shaft by way of a bolt 73 so that upon turning movement of the toggle arm the barrel stop members 58 are each rotated.

Connected to the other end of each of the toggle arms 71 by means of pivot studs 75 are toggle levers 7474 which are connected at their opposite ends to a common pivot stud 76 carried by a clevis bracket 77 fixed to one end of a piston rod 78 of a two-way hydraulic piston unit 79, which is also connected to a suitable source of hydraulic fluid under pressure.

Spaced lengthwise from the barrel stop members 58 is a second stop plate 81 against which the cushion unit base plate 28 abuts when the barrel stop members are turned from a position in which the cylindrical faces 59 lie in the path of movement of the cushion base plate 27 to a position wherein the chord surfaces 61 lie parallel to the plate 28 permitting the latter to move lengthwise. The second stop plate 81 comprises essentially a plate 82 intermediate the sides of which there is fixed a longitudinally extending plate 83 which abuts against and is flxed to another plate 84. On the outer face of the Plate 82 there may be aflixed a rubber cushioning assembly 85 comprising a pair of rubber pads 86 between which there is sandwiched a metallic separating plate 87. The rubber cushioning assembly 85 serves to prevent metal to metal impact. Under some circumstances it may be desirable 3,410,131 I is to further cushion the shock of impact which results when the base plate 28 of the cushion device'Ciabuts against the second stop plate 85. To this end there is provided a spring cage assembly 86 comprising a pair of helical springs 87 which are carried in a housing 88. The housing 88 is disposed between the. plate 84 and plate 90'. Limiting movement of the spring cage assembly 86 are stop pins 89 which ride within elongate slots 91: In this connection it is to be noted that the stopplate assembly 81 is movable lengthwise of the trough'38'on guide strips 92, so that upon impact thereto the plate 84 engages the housing 86 to move the latter againsttheforce of the springs 87. Such compression is limited by the length of the slots 91.

Covering the section into which the cushioning device C is adapted to be inserted is a hinged cover plate 93 to the upper side of which there is fastened lengthwise spaced hinge arms 94 which extend beyond the side channels 32. Hingedly connecting each of the arms 94 tonne of the side channels 32. is a pivot pin 96 which is carried by a pair of outwardly projecting arms 97 fixed to the side web 36. At the other end the arms 94 are, provided with slots 98 which receive locking pins 99 pivotally-carried by a pair of upstanding arms 101 affixed to the opposite side channel 32.

In use, the cushion device is inserted into the trough 38 with one of the base plates 27 disposed within the lengthwise movable base plate retaining means 51 connected to the two way hydraulic cylinder unit 44'. The opposite base plate 28 abuts against the cylindrical faces' 59 of the barrel stop members 57. Thereafter the cylinder unit 44 is actuated so that the piston rod 48 connected'to the plate retainer means 51 moves outwardly, thereby to contract the cushion device against the force of the return spring 26 to the position as shown in FIG. 3. When the cushion device C has been completely contracted to the position shown in FIG. 3 the hydraulic fluid is displaced as described heretofore in connection with the general descrip tion of the hydraulic cushion unit C.

Thereafter, to test the cushioning device C in a manner similar to the conditions which occur in operation in 'a cushion underframe railway vehicle, the toggle linkage 72 is actuated by way of the cylinder unit 79 so as to move the barrel stop members 57 out of the path of movement of the cushion base plate 23, whereupon the cushioning unit return spring 26 is effected to move the piston head assembly 12 and the cylinder 11 outwardly relative to each other until the base plate 28 abuts against the cushion pads 86 of the stop plate 82. It is to be noted that when the circular stop faces 59 are in contact with the base plate 28 to function as a stop surface that there is merely linear contact therewith. Thus, the force of the contracted spring 26 is transmitted radially to the center or pivot connection of the barrel stop 57. Under this condition no forces are imposed on the toggle linkage. No radial force is axially transmitted outwardly through-the toggle arms 71 to the pivot studs to cause further angular outward movement of the levers 74 about the common pivot stud 76. In this manner the barrels do not tend to rotate and receive the full force exerted by the cushioning unit C and thereby prevent inadvertent release of the latter from the contracted position.

To release the cushion unit C from the contracted position it is to be noted that the barrels are rotated so that the two-way cylinder is operated so that the toggle linkage 71 assumes the position shown in'FIG. 3,*in which position the barrel stops 57 are turned sothat the sector faces lie substantially parallel to the sides of the channel permitting a free and uninterrupted release of the cushioning unit to the extended position toward the second stop plate 81. p I

After the above described test procedure has been completed the cushion unit C is inspected to determine whether the components have functioned properly oihave failed. i

I claim:

1. A test fixture for testing a hydraulic cushioning unit device including a fluid filled cylinder, a fluid displacement means mounted for relative reciprocation Within said cylinder for displacing said hydraulic fluid therein to dissipate impact energy during contraction from an extended position, a flexible boot reservoir communicating with said cylinder for receiving a portion of said hydraulic fluid displaced during relative reciprocation, a first base plate fixed to said fluid displacement means, a second base plate fixed to said cylinder in spaced lengthwise relationship to said first base plate and spring means disposed between said first and second base plates for returning said cushioning unit from a contracted to extended position, said test fixture comprising a trough-like support, base plate retainer means mounted for lengthwise movement in said support and adapted to receive one of said first or second cushioning unit base plates, a first stop means mounted on said trough-like support spaced lengthwise from said base plate retainer and adapted to engage the other of said cushion unit first and second base plates, said stop means comprising a pair of transversely spaced barrel members mounted for turning movement about a vertical axis and each having a pair of opposed cylindrical surfaces and a pair of opposed planar sector surfaces, means for turning said barrel members to a position in which one of said cylindrical surfaces is adapted to be engaged by the edges of said other of said base plates and to a position in which said sector surfaces lie in a plane clear of said base plate, means for moving said base plate retainer means toward said first stop means so as to contract said cushioning unit, a second stop means spaced from said barrel members extending transversely across said trough structure and adapted to be engaged by said other base plate when said barrel members are rotated to position in which said sector surfaces lie in a plane clear thereof and said cushioning unit spring means is 0perative to extend said cushioning unit.

2. The invention as defined in claim 1 wherein said means for turning said barrel members includes .a toggle linkage, and power means for actuating said toggle linkage.

3. The invention as defined in claim 2 wherein said toggle linkage includes toggle arms which radially receive the force exerted by the contacted cushioning device when said cylindrical surfaces are engaged by said other of said base plates.

References (Iited UNITED STATES PATENTS 7/1938 De Port 7311 X 9/1964 Posse et al. 73-11