US3224382A

US3224382A - Sliding gate sealing means assemblies

Info

Publication number: US3224382A
Application number: US8367A
Authority: US
Inventors: Walter L Floehr
Original assignee: UNITCAST CORP
Current assignee: UNITCAST CORP
Priority date: 1960-02-12
Filing date: 1960-02-12
Publication date: 1965-12-21
Anticipated expiration: 1982-12-21

Description

Dec. 21, 1965 w. L. FLOEHR SLIDING GATE SEALING MEANS ASSEMBLIES R 1 m m m L F m L m l I I J I l l l l I l I I I l l I II R H m J m W u mm m I I S ||||||.ll|\|.. ll

Filed Feb. 12, 1960 BY w/MM '44 ATTORNEY Dec. 21, 1965 w. L. FLOEHR SLIDING GATE SEALING MEANS ASSEMBLIES 4 Sheets-Sheet 2 Filed Feb. 12, 1960 Y W0 0 ma m L R m m w w W.

39G mm m3 W. L. FLOEHR SLIDING GATE SEALING MEANS ASSEMBLIES Dec. 21, 1965 4 Sheets-Sheet 3 Filed Feb. 12, 1960 Jw Q -6 INVENTOR WALTER L. FLOEHR 4; ATTORNEY Dec. 21, 1965 w. L. 'FLQEHR 3,224,382

SLIDING GATE SEALING MEANS ASSEMBLIES Filed Feb. 12, 1960 4 Sheets-Sheet 4 WALTER L. FLOEHR 4Q, ATTORNEY United States Patent 3,224,382 SLIDING GATE SEALING MEANS ASSEMBLIES Walter L. Floehr, Toledo, Ohio, assignor to Unitcast Corporation, Toledo, Ohio, a corporation of Ohio Filed Feb. 12, 1960, Ser. No. 8,367 17 Claims. (Cl. 105-282) This invention relates to slide gate assemblies for hoppers of railway hopper cars.

The transportation of fine bulk material in railway hopper cars requires the discharge openings of the hoppers to be sealed tightly. It therefore has been the practice to equip cars designed for handling such lading with slide gates rather than drop doors as better adapted to maintain the required tight seal. However, even with a slide gate, it is not economically feasible to provide the close fit between the gate and its slideway which would be necessary were this fit alone depended upon to provide the required tight seal on closing of the gate. Accordingly, it has been the practice in such installations to have some means for forcing the gate, when closed, into tight engagement with its seat. The prior means have been of two general types, one actuated by the closing movement of the gate as it approaches closed position and the other independently actuated after the door has been closed. Theoretically, the former has the advantage over the latter that it is potentially fool-proof, as closing of the gate automatically forces it into tight engagement with its seat. In practice, this potential advantage is difficult to realize, since, if the bulk material is a material such as cement, that has some adhesiveness, the strength of its bond between the gate and the latters seat, when added to the force holding the gate and seat in tight en.

gagement, can readily exceed the force available for opening the door. Although deficient in not sealing automatically, the type of gate which is independently sealed after being closed thus is the more practical in relieving the opening and closing mechanism of the necessity on opening of overcoming the force responsible for holding the gate in tight engagement with its seat.

The primary object of the present invention is to provide in a slide gate assembly an improved slide gate incorporating means for forcing the gate when closed into tight engagement with its seat.

Another object of the invention is to provide a slide gate which not only incorporates means for forcing it into tight engagement with its seat but requires no special construction in the frame in which it slides, thereby enabling a hopper to be fitted interchangeably with the improved and conventional slide gates.

An additional object of the invention is to provide a slide gate carrying means for forcing it into tight engagement with its seat, wherein the means are actuatable mechanically or by fluid pressure and in either case, are rugged in construction and elficient in operation.

Other objects and advantages of the invention will appear hereinafter in the detailed description, will be particularly pointed out in the appended claims and will be illustrated in the accompanying drawings in which:

FIGURE 1 is a plan view of a slide gate assembly including an embodiment of the slide gate of the present invention;

FIGURE 2 is a vertical sectional view taken along the lines 2-2 of FIGURE 1;

FIGURE 3 is a vertical sectional view taken along the lines 3-3 of FIGURE 1;

FIGURE 4 is a fragmentary vertical sectional view on an enlarged scale, taken along the lines 4-4 of FIG- URE 1;

FIGURE 5 is a plan view of a slide gate assembly including another embodiment of the slide gate of the present invention;

FIGURE 6 is a vertical sectional view taken along the lines 66 of FIGURE 5;

FIGURE 7 is a vertical sectional view taken along the lines 77 of FIGURE 5;

FIGURE 8 is a fragmentary vertical sectional view on an enlarged scale taken along the lines 88 of FIGURE 5, with the fluid tube expanded under pressure and forcing the gate into sealing engagement with its seat; and

FIGURE 9 is a view corresponding to FIGURE 8 but with the fluid pressure tube relieved of pressure and the gate released from its seat.

Referring now in detail to the drawings in which like reference characters designate like parts, the improved slide gate, designated as 1, which is a unitary or single, as opposed to a double, structure, forms part of a slide gate assembly 2, installable on a downwardly or bottom opening hopper 3 of a railway hopper car (not shown). As exemplary of applications of the invention, the slide gate assembly 2 of each of the disclosed embodiments is conventional except for its slide gate.

Typically, the illustrated slide gate assembly 2, for the downwardly opening hopper 3 to which it is designed to be applied, has a centrally apertured, downwardly tapering, substantially rectangular frame 4, the upper portion 5 of which is fixed or secured, as by welding, to the side sheets 6 of the hopper about the bottom opening 7 therein. Extending about and instanding substantially horizontally from the side walls 8 of the frame and bounding or surrounding a vertically directed central opening 9 therein, serving as the discharge opening of the hopper 3, is a flange or lip 10, the underface or surface 11 of which is substantially flat or planar. This undersurface 11 is horizontally disposed in the form of frame shown in FIGURES 5-9 and is substantially so in the form shown in FIGURES 1-4 in which the slide gate slides downwardly at a slight incline toward closed position. Also formed on the frame 4 and instanding from its side walls 8 below the discharge opening 9, is a shelf or ledge 12 which confronts and is spaced below and substantially parallel to the underface 11 of the flange 10. The flange 10 and shelf 12, together with the included intermediate portions 13 of three of the side walls 8 of the frame 4, form a substantially U-shaped groove or socket 14 in the frame which is accessible through a horizontally elongated slot 15 interrupting one of the side walls between the flange and the shelf.

The sides or side portions of the shelf 12 and the corresponding or adjoining intermediate portions 13 of the side walls 8 serve as transversely spaced horizontally extending parallel slide-, guideor trackways, each of which is projected or continued outwardly of the frame 4 by one of a pair of side rails 16, conveniently fixed or secured, as by riveting, to gussets 17 integral with and outstanding from the frame 4 at opposite sides of the slot 15. While the pair of side rails 16 may be simply a pair of angle irons connected at their inner ends to the gussets 17 and at their outer ends by a cross-brace 18 and having their horizontally directed legs 19 aligned and co-planar with the sides of the shelf 12, it is preferred to supplement each of these main of supporting irons 16 by an auxiliary or secondary iron 20 fixed to and extending intermediate the ends of the main iron and extending thereabove, with its lower leg 21 bounding the outer side and its upper leg 22 overlying and spaced above the horizontal leg 19 of the supporting iron.

As in a conventional slide gate assembly, the improved slide gate 1 of this invention is inserted in the frame 4 through the slot 15 and projects or extends through that slot and is supported on the shelf 12 and horizontal legs 19 of the side rails 16 in sliding or reciprocating between open and closed positions. Fitted or accommodated in closed position in the groove 14 below and covering or spanning the discharge opening 9, the slide gate 1 is shifted or reciprocated between open and closed positions by a suitable opening and closing mechanism 23, here having an operating shaft 24 journalled in the gussets 17 below the level of the shelf 12 and disposed at right angles to the direction of movement of the slide gate. The illustrated operating shaft 24 is designed to be turned by a capstan 25 through an intervening gear train 26 for increased mechanical advantage and to translate its rotary motion into rectilinear motion of the slide gate 1 through a pinion 27 fixed or keyed to the shaft and engaging a rack 28 formed on the underside of the slide gate. Guided or centered laterally within the frame 4 by the intermediate portions 13 of the latter bounding the sides of the shelf 12, the slide gate 1 is similarly guided outside the frame by the lower legs 21 of the auxiliary angle iron 29.

Identical in the above respects and designed in closed position to seat against the underface 11 of the flange 10 in or on the frame 4 and so seal the discharge opening 9, the slide gates 1 of the illustrated embodiments differ in the means by which they are displaced, moved or forced relative to the frame toward and into sealing engagement with the flange. In both embodiments, the displacing, moving forcing, lifting or raising means is carried by the slide gate and normally retracted so as not to interfere with sliding of the slide gate and is intended to operate only when the slide gate has been shifted to closed position in the groove 14 and the means for actuating the foreing means is both carried by the gate and independent of the frame. However, in the embodiment of FIGURES 9 the forcing means utilizes fluid pressure while in the embodiment of FIGURES 1-4 it is entirely mechanical.

The mechanical forcing means of the embodiment of FIGURES 1-4 is comprised of a pair or plurality of rods 29 each rotatably or oscillatably fitting or seating in one of a pair of downwardly facing or opening grooves, slots or channels 30 formed in and extending longitudinally of the underside 31 of the slide gate or closure member 1. Adjacent opposite sides of the slide gate, the grooves 30 overlie and each preferably is contained or confined laterally within the lateral limits of one side of the shelf 12 and the aligned horizontal leg 19 of the associated side rail 16. In the main cylindrical and contained or confined vertically within one of the grooves 30, each of the rods 29 has fixed to or formed integrally with it, radially projecting or extending earn means, which, for effective centering of the rod in its groove, preferably, are in the form of a plurality of axially or longitudinally spaced cams or cam-shaped lugs 32, one at each end and the other intermediate ends of the rod. In one position lying or contained within the vertical confines of the grooves 31 and extending or projecting into laterally aligned cut-outs or slots 33 in or interrupting the inner walls 34 of the grooves, the earns 32, on partial rotation of the rods 29 from that position, project or extend below the grooves and, by engaging and reacting against the underlying portions of the shelf 12 and the side rails 16, force, lift or cam the slide gate upwardly against its seat on the underface 11 of the flange 10.

Each of the rods has a knob or finger 35 upstanding radially from its outer end portion and projecting or extending upwardly above the slide gate 1 through an aperture 36 therein, the aperture flaring upwardly to accommodate swinging of the knob as the rod is partially rotated or oscillated between the inoperative. retracted or normal and camming, projected or extended positions. In the actuation or operation of the rods 29, each of the knobs 35 forms part of a toggle of which the other part is one of a pair of actuating bars, links or arms 36, each having a socket 37 in its outer end for receiving one of the knobs. Extending transversely of the slide gate 1 and lying or supported on an outer portion 38 thereof at all times outside the frame 4, the actuating bars 36 are pivotally connected to and extend or project from opposite sides of an actuating or operating disc or block 39 pinned or otherwise suitably mounted for rotation or pivoting about a substantially vertical axis on the outer portion 38 intermediate the latters sides. Fitted with a plurality of upstanding circumferentially spaced studs 40 to take a crowbar or like tool (not shown) and with the actuating bars 36 held against disengagement from the knobs 35 by straps 41 fixed to and surmounting the outer portion 38 of the slide gate, the actuating disc 39, on being partially rotated, will act through the toggles formed by the actuating arms and the knobs to rotate the rods 29 correspondingly and cam the slide gate into engagement with its seat 10. If it is desired that the seal between the slide gate 1 and its seat 11 be air as well as lading-tight, this is readily obtainable by applying to the upper face 42 of the slide gate a continuous rubber or like sealing gasket 43 seating in a groove 44 in that face and engageable in the sealed position of the slide gate with the seat-forming underface 11 of the flange 10 about the discharge opening 9.

In the embodiment of FIGURES 5-9 the forcing means is comprised of a fluid pressure transmitter or conductor, preferably in the form of a closed-ended rubber or like flexible tube 45 filled with oil or like suitable fluid and fitting in a passage or channel 46 formed in the slide gate 1. While the passage 46 conceivably could extend entirely around the slide gate, it is only necessary in this embodiment, as in the first, that the force be applied to the sides of the slide gate. Accordingly the preferred passage 46 is substantially U-shaped in plan with each of its pair of end or side legs 47 substantially parallel and extending longitudinally of the slide gate 1 adjacent opposite sides of the latter. Each of the legs 47 overlies one side of the shelf 12 and extends into the outer portion 38 of the slide gate wherein the legs are connected by the transversely extending intermediate or center portion or leg 48 of the passage. The passage 46 is confined or contained entirely within the slide gate except for three slots or openings, one an intermediate or middle slot opening upwardly between the extremities of the intermediate portion 48 and the others a pair of downwardly opening end slots 49, each extending from an outer end of one of the side legs 47 toward its juncture with the intermediate portion 48. As in the illustrated embodiment, each of the slots 49 and 50, is preferably of substantially rectangular cross section and elongated longitudinally of the leg of the passage onto which it opens.

The liquid-filled flexible tube 45, which preferably substantially fills and is coterminous with and of the same configuration as the passage 46, is designed to serve as a liquid conduit or connector between the intermediate slot 50 and the end slots 49 for enabling pressure applied to or impressed on the tube at the intermediate slot to be transmitted or conducted through the liquid to the end portions or legs 51 of the tube exposed at the end slots. For utilizing this capability of the encased flexible tube 45 to force or lift the slide gate 1, once it reaches closed position, into engagement with its seat 11 on the instanding flange 10 in the frame 4, there is provided for each of the end slots a pressure transmitting plate or block 52 of metal or other substantially rigid material. Slidably supported on the underlying side of the shelf 12 and the aligned horizontal leg 19 of the associated side rail 16 during movement of the slide gate 1 between open and closed positions, each of the pressure plates 52 is slidably accommodated, received or fitted in one of the downwardly opening end slots 49. The pressure plates 52 are confined or limited in lateral movement by and preferably of the same cross-section as the end slots 49 and are backed by and have their upper faces 53 in engagement with the end or side portions 51 of the flexible tube 45 exposed or open to the slots.

In normal position, as shown in FIGURE 9, the pressure plates 52 are contained in their respective slots 49 within the vertical limits of the slide gate 1 so as not to interfere with shifting of the latter. However, on application of pressure to the flexible tube 45 over its area exposed by the intermediate slot 50, the end portions 51 of the tube will expand or bulge downwardly, as shown in FIGURE 8, correspondingly projecting or forcing the pressure plates 52 downwardly from or outwardly of their respective slots and by the reactance of the blocks against the shelf 12 forcing the slide gate 1 upwardly against its seat 11.

The force by which the end portions 51 of the tube 45 are expanded and caused through the pressure plates 52 to force the slide gate 1 against its seat 11 is here derived from a shoe or wedge 54 slidably fitted, seated or accommodated in and preferably of substantially the crosssection of the intermediate slot 50. Resting or floating through its substantially flat underface 55 on the portion of the flexible tube 45 exposed or bounded by the slot 50 the shoe 54 has one or preferably a plurality of upwardly facing wedging or camming faces 56, the preferred pair of wedging faces being spaced longitudinally and situated toward opposite ends of the shoe so as to prevent longitudinal rocking of the latter under pressure. Cooperating with the shoe 54 is an actuating or wedging member 57 having a downwardly facing wedging surface 58 confronting and adapted to act on each of the wedging faces 56 on the shoe. Shiftable or reciprocable longitudinally of the shoe 54 and transversely of the frame 4 and here provided with a handle 59 suiting it for manualoperation, the wedging member 57 rides or slides in and reacts upwardly against an open-ended housing or casing 60 fixed to or surmounting the outer portion 38 of the slide gate 1. In process, the wedging or actuating member 57, depending on the direction in which it is shifted, either applies a downward force on the shoe 54 or, by relieving the shoe of that force, permits the latter to return to normal position and, correspondingly, causes the pressure plates 52 to project from or retract into the slide gate 1 While the wedging faces and surfaces 56 and 58 might be in direct contact, it is preferred, particularly if the wedging member 57 is to be actuated manually, to mini- I mize the friction between the wedging member and the shoe 54 by interposing between each wedging'surface and the confronting wedging face a ball or other antifriction means 61 riding in a raceway 62 interrupting the surface and face and sloping in correspondence therewith transversely of the frame 4. Similar to the slide gate of the first embodiment in carrying its own forcing means which acts on its sides for forcing it into sealing engagement with its seat, the slide gate of this embodiment may also be fitted with a sealing gasket 43, if it is desired to seal air-tight the hopper to which it is applied.

From the above detailed description it will be apparent that there has been provided in a slide gate assembly an improved slide gate carrying means for forcing the gate into tight engagement with a seat about a discharge opening of a hopper and thus sealing the hopper against escape of fine lading. It should be understood that the described and disclosed embodiments are merely exemplary of the invention and that all modifications are intended to be included which do not depart from either the spirit of the invention or the scope of the appended claims.

Having described my invention, I claim:

1. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, means carried by said slide gate and operative after said gate has reached closed position for displacing said gate relative to said frame toward and into sealing engagement with a seat on said frame surrounding a discharge opening of said hopper.

2. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions on transversely spaced slideways fixed to said hopper, channels in said slide gate and each opening onto one of said slideways, means carried and normally contained in said channels and pr-ojectable therefrom against said slideways after said gate has reached closed position for displacing said gate relative to said frame toward and into sealing engagement with a seat on said frame surrounding a discharge opening of said hopper.

3. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions on transversely spaced slideways fixed to said hopper, channels in said slide gate and each opening onto one of said slideways, means carried and normally contained in said channels and projectable therefrom against said slideways after said gate has reached closed position for displacing said gate relative to said frame toward and into sealing engagement with a seat on said frame surrounding a discharge opening of said hopper, and actuating means carried by said gate and independent of said frame for projecting said projectable'means from said channels.

4. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions on transversely spaced slideways fixed to said hopper, channels in said slide gate and each opening onto one of said slideways, means carried and normally contained in said channels and projectable therefrom against said slideways after said gate has reached closed position for displacing said gate relative to said frame toward and into sealing engagement with a seat on said frame surrounding a discharge opening of said hopper, means carried by said gate and independent of said frame for actuating said projectable means, and means interposed between said actuating and projectable means for transmitting force therebetween and projecting said projectable means from said channels.

5. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, camming means carried by and oscillatable in said gate and engageable with said frame after said gate has reached closed position for displacing said gate relative to said frame toward and into sealing engagement with a seat surrounding a discharge opening of said hopper, and means independent of said frame for actuating said camming means.

6. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, camming means carried by and oscillatable in said gate and engageable with said frame after said gate has reached closed position for displacing said gate relative to said frame toward and into sealing engagement with a seat surrounding a discharge opening of said hopper, and means carried by said gate and independent of said frame for oscillating said camming means.

7. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, camming means carried by and oscillatable in said gate and engageable with said frame after said gate has reached closed position for displacing said gate relative to said frame toward and into sealing engagement with a seat surrounding a discharge opening of said hopper, and toggle means carried by said gate and independent of said frame for oscillating said camming means.

8. In a slide gate assembly for a downwardly opening hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, camming means carried by and oscillatable in said gate and engageable with said frame after said gate has reached closed position for displacing said gate relative to said frame toward and into sealing engagement with a seat surrounding a discharge opening of said hopper, toggle means carried by said gate for oscillating said camming means, and means rotatably mounted on said gate for actuating said toggle means, said toggle and actuating means being independent of said frame.

9. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions on transversely spaced slideways fixed to said hopper, channels in said slide gate and each opening onto one of said slideways, rod means carried and rotatably seated in said channels, camming means fixed to said rod means and carried and normally contained in said gate, said camming means on rotation of said rod means after said gate has reached closed position being projectable from said gate into engagement with said slideways for displacing said gate relative to said frame toward and into sealing engagement with a seat surrounding a discharge opening of said hopper, and means independent of said frame for actuating said camming means.

It). In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions on transversely spaced slideways fixed to said hopper, channels in said slide gate and each opening onto one of said slideways, rod means carried and rotatably seated in said channels, camming means fixed to said rod means and carried and normally contained in said gate, said camming means on rotation of said rod means after said gate has reached closed position being projectable from said gate into engagement with said slideways for displacing said gate relative to said frame toward and into sealing engagement with a seat surrounding a discharge opening of said hopper, and means on said gate and independent of said frame and operatively connected to said rod means for rotating said rod means and thereby shifting said camming means between normal and displacing positions.

11. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, transversely spaced shelf means on said frame and underlying sides of said gate in the closed position thereof, transversely spaced channels in said gate and each opening downwardly onto one of said shelf means, a rod carried and rotatably seated in each of said channels and contained therein by said frame, camming means fixed to each of said rods and carried and normally contained in the channel thereof in said gate, said camming means on rotation of said rods after said gate has reached closed position being projectable below said gate against said shelf means for displacing said gate relative to said frame toward and into sealing engagement with a seat surrounding a discharge opening of said hopper, means fixed to and upstanding radially from each of said rods above said gate, and means rotatably mounted on said gate and independent of said frame and operatively connected to said upstanding means for rotating said rods and thereby shifting said camming means between normal and displacing positions.

12. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, transversely spaced shelf means on said frame and underlying sides of said gate in the closed position thereof, transversely spaced channels in said gate and each opening downwardly onto one of said shelf means, a rod carried and rotatably seated in each of said channels and contained therein by said frame, camming means fixed to each of said rods and carried and normally contained in the channel thereof in said gate, said camming means on rotation of said rods after said gate has reached closed position being projectable below said gate against said shelf means for displacing said gate relative to said frame toward and into sealing engagement with a seat surrounding a discharge opening of said hopper, means fixed to and upstanding radially from each of said rods above said gate, means rotatably mounted on said gate outwardly of said frame, and links pivotally connected to said rotatably mounted 8 means and each connected to one of said upstanding means for moving said camming means between normal and displacing positions on rotation of said rotatably mounted means, said rotatably mounted means and links being independent of said frame.

13. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, and fluid pressure means carried by said gate and operative after said gate has reached said closed position for displacing said gate relative to said frame toward and into sealing engagement with a seat surrounding a discharge opening of said hopper.

14. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, slots in said gate and each opening downwardly onto a portion of said frame in the closed position of said gate, a pressure plate carried in each of said slots and normally retracted thereinto, a fluid pressure conductor in said gate and backing said pressure plates, and means carried by said gate and shiftable relative thereto after said gate has reached closed position for applying pressure to said conductor and thereby projecting said pressure plates from said slots against said frame portions and displacing said gate relative to said frame toward and into sealing engagement with a seat surrounding a discharge opening of said hopper.

15. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, slots in said gate and each opening downwardly onto a portion of said frame in the closed position of said gate, a pressure plate carried in each of said slots and normally retracted thereinto, a fluid pressure conductor in said gate and backing said pressure plates, and wedging means carried by said gate and shiftable relative thereto after said gate has reached closed position for applying pressure to said conductor and thereby projecting said pressure plates from said slots against said frame portions and displacing said gate relative to said frame toward and into sealing engagement with a seat surrounding a discharge opening of said hopper.

16. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, slots in said gate and each opening downwardly onto a portion of said frame in the closed position of said gate, a pressure plate carried in each of said slots and normally retracted thereinto, a flexible fluid pressure conductor in said gate and backing said pressure plates, an upwardly opening slot in said gate outwardly of said hopper and opening onto said conductor intermediate ends thereof, a shoe in said slot and riding on said conductor, and actuating means on said frame and operative after said gate has reached closed position for applying a downward force on said shoe and through said conductor projecting said pressure plates downwardly from their slots against said frame portions and displacing said gate relative to said frame toward and into sealing engagement with a seat on said frame surrounding a discharge opening of said hopper.

17. In a slide gate assembly for a hopper, the combination of a single slide gate slidable between open and closed positions in a frame fixed to said hopper, slots in said gate and each opening downwardly onto a portion of said frame in the closed posiltion of said gate, a pressure plate carried in each of said slots and normally retracted thereinto, a flexible fluid pressure conductor in said gate and backing said pressure plates, and wedging means shiftably mounted on said gate and engaging said shoe, said wedging means being shiftable after said gate has reached closed position for wedging said shoe downwardly against said conductor and therethrough projecting said pressure plates outwardly of their slots against said frame portions and displacing said gate relative to said frame toward and into sealing engagement with a seat on said frame surrounding a discharge opening of said hopper.

References Cited by the Examiner UNITED STATES PATENTS Rettig 105 2s2 Canda 20-23 Thompson 20-23 Garbe 2s1 203 X 10 Whaley 251-203 X Hankins 105-282 Hankins 105-282 Redmond 20-69 Smith 20-69 X Dorey 105-282 Lindstrom 105-253 Beauchamp 105-253 FOREIGN PATENTS Germany.

MILTON BUCHLER, Primary Examiner. JAMES S. SHAN-K, LEO QUACKENBUSH,

Examiners.