US3004499A - Railway car coupler clamping apparatus - Google Patents

Description

Oct. 17, 1961 Filed May 15, 1959 5 Sheets-Sheet 1 .ZIg Z uzc a2 E: t: 46 47 23 z i 4/ 46 .59 mi 1/ 42- m T 43 I //VI/EN7'0A 5.

LEE H. STRAIGHT LYLE AHAMSEN AM M Oct. 17, 1961 H. STRAIGHT ETAL 3,004,499

RAILWAY CAR COUPLER CLAMPING APPARATUS Filed May 15, 1959 5 Sheets-Sheet 2 W e/woes. LEE H. STPA/GHT m5 4. H/l/YSE/V BY Lou 6 v Arrows fr;

Oct. 17, 1961 H. STRAIGHT ETAL 3,004,499

RAILWAY CAR COUPLER CLAMPING APPARATUS 5 Sheets-Sheet 3 Filed May 15, 1959 H6 N VN ET M 4 E f Oct. 17, 1961 H. STRAIGHT ETAL 3,004,499

RAILWAY CAR COUPLER CLAMPING APPARATUS Filed May 15, 1959 5 Sheets-Sheet 5 3,004,499. RAILW Y AR COUPLER MP APP RAI S Lee'I-I; Straight, Adel, and Lyle A. Hansen, Des Moines, Iowa, asslgnors to Straight Engineering Company, Adel, Iowa, a corporation of Iowa Filed May 15, 1959, Ser. No. 813,390 8 Claims. (Cl. 104-449) This invention relates to that type of apparatus adapted to unload a railway freight car carrying readily flowable bulk materials, and more particularly to means clampable on; each coupler at; the end of the car for locking the car in place during the unloading operation.

To accomplish the unloading operation, the apparatus employs a movable cradle for supporting the car to be emptied, which after removal of the grain door mounted in the side of the car, is; tilted transversely and then rocked longitudinally in a sequential manner to cause all of the material to flow out; of the doorway and into a floor pit or hopper.

Before the car is tilted, it is centered longitudinally of the cradle by meansof movable clamp supports adapted to hold and lock the couplers of the car against longitudinal and transverse movement. Itis, therefore, an object of this invention to provide an improved clamp support adapted to. be applied to. the coupler at each end of the car for lock ng the car against both longitudinal and transverse movement relative to the cradle apparatus.

It has been found in actual practice that the tracks for supporting the car on the cradle can be tilted transversely to an inclination of substantially fifteen degrees to the horizontal while still maintaining the center of gravity of the car and its load in a vertical plane between the car supporting rails to prevent the car from being over-balanced by gravity. It; has also been found, that by providing as part, of each. clamp support ameans for applying a pressure on the top of the coupler, that the transverse inclination of the car may be increased to per mit a more efiective unloading while yet retaining the car on its tracks while so inclined.

The difliculty encountered, however, by the type of clamp; supports employing a hold down pressure is the. possibility of applying a downward pressure greater than the safe-breaking load of the coupler. such as this where the safety factor must, be high, such possibility must be eliminated. To do so is one Gi ie objects ofthis; invention. Reasons for the above-mom tioned difficulty are, the known factors that couplers in cars of dilferent makes are, known to vary height, and that the height of a coupler will change or vary according to, the car load. Thus, the effectiveness of an ap.-. plication of a predetermined or any amount of downward pressure on a given coupler is initially burdened with these several variables.

Another object, therefore, of this invention is to pro- In operations-- United States Patent vide an improved clamp support of the type, and for the purposed' described, which is automatically adjustable to receive a car coupler, and wherein a hold-down pressure or support is continually available by the clamp support for the coupler, but which pressure is not applied or I utilized unless necessary.

A further problem in this operation is that of an operator, having immediate knowledge of whether or not the clamping assembly hasreceived and is holding the car coupler, prior to the tilting operation for unloading the car. Another object of this invention, therefore, is the provision of a clamping assembly that indicates im-. mediately at a location. remote from the coupler whether or not receipt of the car coupler by the clamping assembly is, proper at the time of the initial engagement therebetween.

Patented Oct. 17, 1961 ice Yet a further object of this invention is to provide aelevation a clamping assembly of this invention in changed positions therein;

.FIG. 2 is an enlarged, fragmentary plan view of the frame, and wheels of the clamping assembly, with certain parts broken away and others shown in section for the purpose of clarity;

FIG. 3 is an enlarged, rear end elevational view of the clamping, assembly, with some parts broken away and with others shown in fragmentary sectional form for the purpose of clarity;

FIG. 4: is a vertical. sectional view taken at 4-4 in FIG. 3, and showing some parts of the freight car in section and others in side elevation;

FIG. 5 is a fragmentary, perspective detail view of a safety mechanism for the clamping assembly;

FIG. 6. is an enlarged, fragmentary perspective view of the front of the upper part of the clamping assembly, with certain parts broken away'for the purpose of clarity;

FIG. 7' is an enlarged, fragmentary, perspective detail view of the rear of the block of the clamping assembly, with certain parts broken away to more clearly show its construction;

RIG. 8 is a cross-sectional view taken along the line 8-8 in FIG. 7, and illustrating one manner in which the clamping assembly block is operated by the car coupler, with certain parts broken away for the purpose of clarity;

FIG. 9 is an enlarged, perspective view of the structure of KFIIG. 6 in an exploded manner; and

FIG. 10 is a schematic of the electrical circuit for the limit switch.

Referring now tothe drawings, one end of a freight carunloader 20 of the tiltable type is illustrated in FIG. 1 in a lowered, level position in a pit 21 provided therefor, and with a freight car 22 positioned on the unloader'Zll. One'embodiment of'the clamping assembly of this invention is illustrated generally at 23 in FIGJI and is dis-- closed i i solid lines in a near-operative positive relative to the car 22, and in dotted lines in an inoperative position in a; pit 24 provided therefor so that the car 22 can be rolled onto and ed of the unloader 20.

The utilization and operation of an unloader of the tiltable type is well known, reference being had to. US. Patent No. 2,786,586, issued March 26, 1957, to A. G. Hague and 'H. R. Straight, entitled Car Dumping Apparatus. Briefly, the operation is as follows: Assuming the clamping assembly 23 has been moved down an inclined track 26 into the pit 24 by a pair of longitudinally movable arms 27 attached thereto (FIG. 2), the freight car 2 2 to be dumped is rolled olf a stationary track 28 onto the track 29 of the unloader 20. A motor driven sprocket andchain unit (not shown) but of the type disclosed in United States Patent No. 2,834,486 is cohnected to each clamping assembly 23 by the arms or links 27, which are movable horizontally in reversed directions in; response to the operation of such unit. With the car 22 centered approximately on the unloader the operation of the sprocket and chain unit provides for the clamping assemblies 2?; at the ends of the unloader, being pulled toward each other through the arms 27, to positions on the track 26 and into engagement with a corresponding conventional coupler 21 at each end of the car 22.

When the operator is certain that both clamping assemblies 23, or clamps 23 for convenient terminology, are properly engaged with the couplers 31, the entire unloader 20 is tilted transversely and then rocked longitudinally, with the sequence being'repeated until the grain, or whatever granular material the car is carrying, is unloaded.

The present invention pertains particularly to the clamp 23 for holding the car coupler 31 against longitudinal and vertically upward movement, whereby the car 22'is held stationary relative to the unloader 20 during the tilting operation. Generally, the clamp 23 (FIG. 4) comprises a frame 32, a head unit 33, a switch actuating unit 34, a stabilizing unit 36, and a safety unit 37.

The frame 3'2 (FIG. 4) has a lower portion 39 which is enclosed, except fora rear access plate 40, is mounted in an offset manner on a pair of axle housings 41 and 42, for axles having rotatable wheels .43 (FIGS. 2 and 3) at their outer ends. Of note, the arms 27 are pivotally mounted on the front axle housing 41.; .The upper portion 44 (FIGS. 3 and 4), of the frame 32 includes a pair of upstanding, transversely spaced side walls 46 connected at their upper ends by a top member 47 and at their lower ends by a horizontally disposed plate 48 (FIG. 6) which separates the upper portion 44 from the lower portion 38 of the frame 32. The front of the upper portion 44 is open whereas the rear is closed by an access plate 45 (FIG. 4).

An H-shaped plate49 (FIG. 9) is secured in an.upstanding manner between the side walls 46 and on top of the separating plate 48, and is provided with a boxshaped member 51 secured to its rear end and extended rearwardly for securement to a rear portion 50 (FIG. 4) of the frame 32. A pair of right angular members 52 (FIG. 2) are secured in a transversely spaced upstanding manner to the back side of the plate 49 (FIG. 9) Below theseparatingplate 48, a pair of transversely extended supporting straps 53 (FIG. 4) are secured between the side walls 46, and a collar member 54 is secured to the underside of the plate 48 directly underneath a longitudinally extended slot 55 (FIGS. 6 and 9) formed therein.

The head unit 33, best illustrated in FIGS. 6 and 9, is the actual structure of the clamp 23 provided for/the purpose of receiving the knuckle part 56 (FIG. -4) of the coupler 31 in the'manner of a socket receiving a ball. Theunit'33 includes a pair of transversely spaced, upstanding side.elements 58 secured in a parallel manner at their lower ends by a flat upstanding member 59 and having four openings 60 formed therein through which cap screws 61 are inserted for threaded engagement in registrable openings 62 formed in the H-shaped plate 49 (FIG. 9). A solid head member 63 (FIG. 9) is secured to and extended between the side elements 58 and at a spaced distance above the upper edge 64 of the flat member59, so that a slot 66 is formed, the head member 63 being provided with a face 67 curved in a manner complementary-to the face of the coupler knuckle 56 so as to receive it in such a way as to prevent lateral movement thereof. 7 To provide-for the horizontal insertion of a switch actuating plate 68 (FIGS. 6 and 9) through the slot 66, a pair of angle members 69 are secured, as by bolts 71 to'the side elements 58 and spaced belowthe member 63.

side elements 58, it may be seen that the actuating plate- 68 is thereby limited in its horizontal sliding movement rearwardly through the slot'66. The plate 68 is normally biased forward through theslot 66 by means of a pair of elongated, spring steel straps 79 (FIG. .3) each of which is secured at its lower end to the fiat member 59 and which contacts a rear shoulder 80 9) of the plate 69. w

A micro-switch 81 (FIGS. 3, 4 and 10) of a conventional type is secured to the rear or back side of the fiat member 59 between the springs 79, and is positioned so that its exposed actuating roller 82 is engageable by the finger 78 ofthe actuating plate 68. Thus, theplate 68 under the bias of the springs 79 is normally held spaced from the micro-switch roller 82; -howe"er, upon the plate being pushed rearwardly or toward the side elements 58, the finger 78 thereof is adapted to engage the roller 82 and actuate the switch 81 for a purpose described hereinafter.

The stabilizing unit 36 comprises a variable block group 86 (FIGS. 4 and 8) and a compression spring group 87 (FIG. 4), both of which are interconnected by an elongated rod 88. The block group-86, best illustrated in FIGS. 6, 7 and 8, includes a substantially square housing 89 having a pair of transversely spaced side members 91' and 92, a top wall member'93 and a bottom wall member 94, and with apassage through the housing r from the front to the rear thereof.

The top wall 93 overhangs the remainder of the housing 89. A pivot pin 97 (FIG. 7) is extended transversely through the housing 89 for supporting a large hanger and the plate 99 is contiguous with the plate 102.

Both plates 99 and 102 are biased forwardly until their respective arms 103 and 104 contact the inner face 106 of the top wall 93 (FIG. 8), by a pair of leaf springs 107 and 108. Each spring is secured at its one upper end to the top-of the wall member 93 and at its other lower end to a respective hanger. By this arrangement, the lower plate 99 can beswung rearward-1y without affecting the'upper plate 102; however, should the upper plate 102 be pushed rearwardly, its hanger 101 will necessarily strike the spring 107 of the larger hanger 98 whereby both plates ,are forced rearwardly.

- tom wall 94 (FIG. 8), is inserted through a hole 113 The arrangement is such that the horizontal leg 72 of each angle member 69 is even with the upper edge 64 of the 'slot '66, thereby serving as horizontally disposed shelf on which the actuating plate 68 is slidable. To prevent transverse movement of the plate 68, a pairof blocks 73 are mounted on bolts 74 provided therefor on each horizontal leg 72 of each member 69 (FIG. 9), the blocks serving as side guides for the plate 68. p

The actuating plate 68 (FIG. 9), Part of the switch actuating unit 34, is T-shaped, having a pair of laterally extended arms 76, an elongated slot 77 formed in the main. portion thereof, and provided with a finger 78 (see FIG, 4) extended rearwardly therefrom.- As the arms 76 have a width whereby they are adapted to strike the (FIG. 9) provided thereforin the head member 63 through the elongated slot 77 in the switch actuating plate 68 through the slot 55 in the separating plate 48, and final- 1y through the collar 54 (FIG. 4) from which it depends for attachment with a supporting plate 114 within the lower portion 38 of the frame 32. Another collar 116, similar to the collar 54, is mounted on the supporting plate 114, whereby a coilspring 117 is mountable about the collars 54 and 116 and inserted between the separating plate 48 of the frame and the supporting plate 114 of the stabilizing unit 36 (FIG. 3). A plurality, four in number, of bars 118 are securedbetween the plates 48 and 114 for confining the spring 117. i

Referring'now to FIGS. 4 and 5, the safety unit 37 includes -a free swingingloclc arm 121 pivotally mounted at its top to a pin "122 in turn rotatably mounted ina bearing housing 123. The housing 123 is integral with spotted a plate,.12,4, secured, as. by cap, screws 126,. to a side ofin an upstanding, longitudinally spaced manner on an;

elongated bar 132 secured to a floorpiece 13 3 of the unloader 20 and running lengthwise underneath the clamp 23 in an offset manner best shown in FIG; 4. \A strap 134 of spring steel is secured to the end 1270f the arm and is biased; slightly away fromthe. fiat'surface 136 to which it is adjacent, for a purpose hereinafter described.

The operation of the improvedzcarclamp 23 of this, invention is as follows. Assuming that' the box can 22 (FIG. 1) is on the track 290i the unloaderlt), the horizontal movement of the arms 2 7 toward the center of the unloader results in the carclamp 23 being pulled up from its dotted line normal position in the pit 24 (FIG.

1) to afull-line elevated position on its own track 25.

where the head 63 is substantially level with the car coupler 31 which includes the pivoted knuckle 56. As the clamp 23 continues to be advanced, the knuckle 56 is initially engaged by the head 63 (FIG. 4), and then forced inwardly against shock absorbing means (not shown) of the freight car until a firm complementary engagement is had between the head 63: and theknuckle 56. For reasons of clarity, the illustrations in FIGS. 4. and 8 show the engaged (dotted lines) and disengaged (full lines) positions of. the coupler knuckle 56 as though it moves relative to a sta'tionary clamp 23. As just described, in actual operation the opposite is true with the clamp 23 moving toward and away from the coupler 31.

In line with the advancement of the clamp 23 into engagement with the coupler knuckle 56, the oifset nature of the frame unit 32 and the other associated units mounted on the wheels 43 provides for the head 63 (FIG. 4) of each clamp pivotally moving the respective coupler 31 which it contacts in a transverse or lateral manner within itssupporting pocket or housing. This forces the coupler drawbar 143 up against one side of its housing so as to take the slack out of the car coupling arrangement and also out of the car axle bearings to prevent any transverse movement of the car during the tilting operation. This provision formsno part of the invention.

It should here benoted that thedimensional design of the clamp 23 is such that the height of the bottom 100(FIG. 8) of the top wall 93. is sufficient to provide a vertical space below it to accommodate a coupler at, the highest allowed manufacturing limit, and additionally that the location of the switch actuating plate 68 relative to, the head, member 63 assures its being contacted by theknuckle. 56, providing the knuckle 56 and the head face 67 are properly mated. The movement of the switch actuating plate 68 against the roller 82 actuates and closes theswitch 81 (FIG. This action permitsv current to flow through a lamp 83 remote from the clamp 23 thereby indicating a proper engagement of the car coupler 31 by the clamp head 63.

As such proper engagement is indicative that the top wall 93 (FIGS. 4 and 8) of the coupler stabilizing unit 36 has. moved in over the top 105 of the knuckle 56, itis alsoindicative that the knuckle has contacted one or both the. sandwich plates 99 and 102 whereby to automatically provide for the closest spacing between the top 105 (FIG. 8') of the knuckle 56 and the bottom of a stationary element of the block group 86 maintainedv directly above it, whether that element be the top wall 93 or one of the plates 99 or 102, whereby to prevent transverse movement of the car 22 during the tilting operation by positive stabilization of the coupler 31. Putting it another way, the, height of the coupler itself automatical- 1y determines the vertical proximity of the knuckle 56 with: the adjustable block group 86. for obtaining the closest fit therebetween. This, fit, however, is without an initial. downward hold down pressure.

Referring to FIG. 4, the knuckle 56, while forcing ack, the. plate 78 t engage, th sw t h o e 2, has

imultaneous y e gage and. forced back the o r plat 99 of the large hanger '98 and thus placed itself c ose y and directly below the upper plate '102. And as seen, in FIG. 8, should the coupler 31 be riding onthe high side, it can contact and force backthe upper plate 102, and therefore the lower plate 99, thus placing itself closely beneath. the-top wall 93., Although only two plates,

99 and 102 are disclosed, it may readily be seen that by varying the vertical thickness of these plates, one or more additional plates could be incorporated into the block group 86 thus making the variable space between the, top 105 of. the coupler, and the bottom of a plate. member of the block group 86 evenmore small.

By this arrangement of the block group 86 (FIG. 8),

the object of stabilizing the, coupler 31 by minimizing the space between it and a particular element of the hold down block group 86 is accomplished. Concurrent with this accomplishment, as there is always at least the minimal space mentioned. above, upon the initial engagement of the coupler 31 with the head 63 the dual nature !of the variable block group 86 also accomplishes the elimination of an initial hold-down pressure on the top of the coupler 31.

As mentioned hereinbefore, the coupler has a safe breaking load, and one important factor in determining that load is a drawbar support 141 (FIG. 4), which with another bar forms the transverse supporting base of a hanger unit 142 (FIG. 1) which is attached to the end. of the box car 22 and through which the coupler drawbar 143 extends. Assuming the box car 22 is loaded and the coupler 31 is high due to its manufacture, it is known that as the car is unloaded its body to which the coupler is connected tends to raise off its wheels due to the load on the car truck spring being relieved. It has been found that when car clamps are used which apply an initial downward force on the car coupler, in resisting the additional force of the car coupler during the unloading, such compounded strain on the coupler by the car tends to bend and even break the drawbar support 141.

Referring to FIG. 8, it can be observed that when the block group 86 of the clamp 23 has engaged the coupler knuckle 56 (shown in dotted lines), and when the knuckle. has been driven inwardly of the car against a shock absorbing unit (not shown) provided therefor, by forcing back both plates 99 and 102, the top 105 of the knuckle is spaced slightly from the bottom 100 of the top wall 93. The amount of this space is sulficiently small that should the car 22 tend to shift slightly in a transverse manner while in an inclined position, the knuckle 56 would contact the top piece 93 and be held thereby, thus steadying the car 22 before the sudden shift could be harmful. Upon the contact of the coupler knuckle 56 with the top wall, whether by a sudden shift of the car 22 due to an unusually high wind velocity or due to a gradual raising of the knuckle while the car is being unloaded, this upward force is resiliently restrained by the top wall 93 transmitting the force through the rod 88 (FIG. 4) and the supporting plate 114 to the coil spring 117. This arrangement provides sufficient resistance to retain cars loaded to the maximum weight on the cradle tracks 29.

Assuming the car 22 has been centered and lockedby the clamps 23 (only one showing) and is in a tilted position of, for example, fifteen degrees off the horizontal, the safety unit 37 becomes operative. As the car 22 and the clamp 23 are always tilted one way, or in a clockwise direction as viewing FIG. 3, the free swinging lock arm 121 will swing toward and between, in a longitudinal ly aligned manner, a pair of the teeth 131. The latter are mounted in a prearranged spacing to provide for box cars of different lengths and makes, so that, with the complementary diagonal cuts on the lower end 127 of the arm 121 and on the teeth 131, movement of the end 127 in alignment between a pair of teeth is ensured.

Thus, should the unloader mechanism holding via the arms 27 the clamp 23 fail, the clamp and the car 22 will be, held substantially in place by the arm end 127 contacting'the adjacent tooth 131 to its rear, or to the left as viewed in FIG. 4. The purpose for the spring steel strap 134 (FIG. is to maintain a resilient structure between the face 136 of the arm 1'21 and the adjacent face of atooth' 131 whereby to prevent a bind therebetween, which if allowed to exist could prevent the arm 121 from freely'swinging back to its normal position (FIG. 3) when the car and clamp are righted from their inclined positions. This type of bind has occurred in actual unloading, where without the strap 134, the face 136 was closely adjacent a tooth 131 when the clamping was com-' pleted, and was then moved into engagement therewith due to a slight lengthening of the car 22 as it was being unloaded.'

, Although a preferred embodiment has been disclosed herein, it is to be remembered that various modifications and alterations can be made without departing from the scope of the invention as defined in the appended claims.

We claim:

1. A coupler clamping assembly for a railway box car unloaderrnounted to tilt transversely of itself and adapted to support a box car having a conventional box car coupler at each end thereof, said assembly including a frame mounted on said unloader for movement toward and away from a coupler, a coupler engaging head member mounted on said frame, and means yieldably mounted on said frame and including a plurality of pivotally mounted plates arranged in a horizontally disposed, vertically stacked manner whereby one or more of said plates are engageable by said coupler when engaging said head member and are pivotally moved thereby, with one or more remaining plates extended above said coupler.

2. A coupler clamping assembly for a railway box car unloader mounted to tilt transversely of itself and adapted to support a box car having a conventional box car coupler at each end thereof, said assembly including a frame mounted on said unloader for movement toward and away from a coupler, a coupler engaging headmember mounted on said frame, adjustable means for stabilizing said coupler yieldably mounted against upward movement to said frame and adapted to extend over and above said coupler when engaging said head member, actuating means mounted on said frame and movable by and with said coupler, and other means responsive to said actuating means for remotely indicating the engagement of said coupler with said head member.

7 r 3. A coupler clamping assembly for a railway box car unloader mounted to tilt transversely of itself and adapted to support a box car having a conventional box car coupler at each end thereof, said assembly including a frame mounted on said unloader for movement toward and away from a coupler, a head member mounted on said frame and adapted to engage said coupler, coupler stabilizing means including a block unit overhanging said head member, means attached to said frame and yieldably. maintaining said block unit a predetermined distance above said head member whereby said block unit is adapted to overhang said coupler when said coupler is engaged, and a plurality of plate elements movably connected to said block unit and arranged in a sandwich manner thereunder, each of said plate elements being movable out from under said block unit upon contact by said coupler.

. 4. A coupler clamping assembly for a railway box car unloader mounted to tilt transversely of itself and adapted to support a box car having a conventional box car coupler at each end thereof, said assembly including a frame mounted on said unloader for movement toward and away from a coupler, a coupler engaging head member mounted on said frame, stabilizing means mounted on 8 ber, and including further plural means having parts attached to said block unit and mounted directly underneath whereby to also overhang saidhead member and being engageable by said coupler, one or more ofsaid parts of said pluralmeans being movable away from a position overhanging the head member, upon contact by said coupler, whereby the remaining one or more parts remain in the position overhanging said head member.

5. A coupler clamping assembly for a railway box car unloader mounted to tilt transversely of itself and adapted to support a box car having a conventional box car coupler at each end thereof, said assembly including a frame mounted on said unloader for movement toward and away from a coupler, a coupler engaging head member mounted on said frame and having a surface facing said car coupler, with said surface being complementary to the coupler face, coupler stabilizing means including a plurality of elements resiliently mounted to said frame for vertical movement as a unit, said elements being arranged one on top of another and spaced above said head member in an overhanging manner, each of said elements movably mounted to another element thereabove and being movable upon contact with said coupler out of said overhangingposition.

6. A coupler clamping assembly for a railway box car unloader mounted to tilt transversely of itself and adapted to support a box car having a conventional box car coupler at each end thereof, said assembly including a frame mounted on said unloader for movement toward and away from a coupler, a head member mounted on said frame and adapted to engage the coupler in a complementary manner, a block unit, a rod connected at one end to said block unit and-at the other end to a plate, stop means secured to said frame, means inserted between said frame and said plate wherebyto bias said block unit downwardly toward engagementwith said stop means, saidblock unit including a top wall secured above said head member and which is adapted to extend over said coupler when engaged with said head member, and a plurality of plate elements arranged in a vertically stacked, sandwich position, each of which'is pivotally mounted to said block unit for being swung from the sandwich-like position relative to each other and directly below said top Wall to a position'out from under said top Wall on engagement by said coupler, whereby a plate element remaining below said top wall after engagement of said coupler with said head member remains positioned above said coupler.

7. A coupler clamping assembly for a railway box car unloader mounted to tilt transversely of itself and adapted to support a box car having a conventional box car coupler at each end thereof, said assembly including a frame mounted on said unloader for movement toward and away from a coupler, a coupler engaging head member mounted on said frame, means resiliently mounted to said frame and biased against movement upwardly therefrom, a plurality of horizontally disposed, flat elements each pivotally mounted to said means and arranged in a vertically stacked manner, at least one of said flat elements adapted to move over the top of said coupler when the coupler engages said head member so as to be engageable by said coupler on upward movement thereof, an actuating plate reciprocally mounted in said frame below said head member spaced distance above so as to overhang said head memand biased toward the coupler so as to be engageable by said coupler when engaging said head member, and a switch operable by said actuating plate when engaged by said coupler whereby to energize a remotely placed indicating means in a circuit provided therefor.

8. A ccuplerclamping assembly for a railway box car unloader mounted to tilt transversely of itself and adapted to support a box car having a conventional box car coupler at each end thereof, said assembly including a frame mounted on said unloader for movement toward and away from a coupler, acoupler engagyieldably mounted on said frame above said head member including a top member and a plurality of movably mounted plate members arranged below said top member in a horizontally disposed, vertically stacked relatiOn whereby one or more of said plates are engageable by said coupler, when engaging said head member, and moved thereby so that a movable plate or said top memher is extended above said coupler.

References Cited in the file of this patent UNITED STATES PATENTS Ottenstein July 26, 1932 Turner et a1. Dec. 22, 1936 Voigt Sept. 4, 1951 Bonanno Dec. 6, 1955 Hague Nov. 26, 1957 Straight et a1 May 13, 1958

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