BACKGROUND OF THE INVENTION
Railroad hopper cars carrying bulk particulate material, such as grain, plastic pellets or powered or granular products, are typically unloaded by applying a vacuum conveying line to an outlet gate positioned at the bottom of each car compartment. The primary airflow for the vacuum conveying line is obtained from the exterior of the railroad car. That it, the exhaust air for unloading is not drawn from the car compartment through the particulate matter but is drawn from outside the railroad car. Accordingly, the top of the car compartment must be vented to compensate for the particulate material drawn out the bottom of the compartment. Failure to vent the top of the compartment will reduce the efficiency of the vacuum unloading process and may even risk damage to the car structure. Manufacturers have responded to this problem by providing hatch covers that have filtered vents, however, for some types of materials, for example, materials used or intended for use as pharmaceuticals, such particulate materials must be protected against all types of contaminants even those which could pass through a screen or filter. In such situations, a solid hatch cover is required. A shipper of such sensitive materials who receives a hopper car having a vented hatch cover must either reject the car or replace the vented hatch cover with an unvented hatch cover. Likewise, a shipper who receives a hopper car with an unvented hatch cover and wishes to use a vacuum conveying line for unloading must replace the unvented hatch cover with a vented hatch cover.
The hatch cover of this invention permits easy replacement of a vented hatch cover with an unvented hatch cover or vice versa simply by changing only one component part of the hatch cover. This component which may be called a frame or a hatch opening closure member is held in position by a retaining ring which is attached to the underside of the hatch cover. In applicants' invention, one embodiment of the frame has a center portion in the form of a screen. This embodiment of the frame can be replaced with another embodiment of the frame which has a center portion in the form of an imperforate closure member, and vice versa. Removal and replacement is accomplished simply by opening the hatch cover, removing the existing frame from the retaining ring on the underside of the hatch cover and press fitting a new frame into the retaining ring. There are no fasteners to be removed and reinstalled.
SUMMARY OF THE INVENTION
The present invention permits the use of a single hatch cover for both vented and unvented service on a covered hopper railroad car simply by changing only one component of the hatch cover assembly, namely the frame which is made in two embodiments, one with a screen and the other with an imperforate closure portion.
The frame may either have a center screen for vented operations or an imperforate closure portion for unvented operations. The frame may easily be replaced because there are no fasteners to be removed and reinstalled when the frame is removed and replaced. The frame which has either a center screen or a center imperforate portion includes an integrally formed gasket as its outer periphery. The gasket is press fitted into a retaining ring attached to the underside of the hatch cover. The other side of the gasket engages and seals the coaming of the hatch opening which leads into a storage compartment of a railroad hopper car. When engaging the coaming, the frame is held in place over the compartment opening by the weight of the hatch cover and the latching force acting against the hatch cover. When the hatch cover is opened, the frame and its gasket move away from the coaming with the hatch cover.
In order to accommodate itself to all of the different climatic conditions to which a railroad covered hopper car is exposed and without losing its sealing effectiveness, the frame is made of a flexible material, either natural or synthetic, which allow it to retain its flexibility and resiliency under variable weather conditions. The material from which the frame is made is selected to have a coefficient of expansion much greater than the coefficient of expansion of the material used to make the hatch cover and to which the frame is attached and held by a press fit.
To facilitate opening and closing of the hatch cover to change the frame or to load cargo into the compartment, a self adjusting hand operated latch is provided. When the latch is in its latched or locked position, it applies constant pressure to the hatch cover to maintain the gasket in a sealed condition against the hatch coaming regardless of the particular design of the hatch coaming which varies by manufacturer. The hand operated latch also eliminates the need for a hold down arm for the hatch cover.
The design of the hand operated latch of this invention with its resilient flexible attachment to the coaming instead of a fixed pivotal mounting permits its installation on hatch coamings of various manufacturers. Its resilient flexible attachment to the coaming and its slide-on, slide-off pivot attachment to the hatch cover adjusts for hatch covers and hatch cover mounting hardware of various sizes. The mounting of the latch provides an over-center locking arrangement for the latch mechanism which along with its flexibility and resiliency holds the hatch cover securely in its closed position in spite of wide temperature variations and operating conditions experienced by a covered hopper car during its travels.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is illustrated more or less diagrammatically in the following drawings wherein:
FIG. 1 is a top plan view of the hatch cover assembly of this invention with some parts broken away and others shown in cross-section for clarity of illustration;
FIG. 2 is a side elevational view of the hatch cover of FIG. 1 with some parts broken away and other parts shown in cross section for clarity of illustration;
FIG. 3 is bottom plan view of the hatch cover of FIG. 1;
FIG. 4 is a top plan view of the annular ring of the hatch cover;
FIG. 5 is a top plan view of the hatch opening filter of this invention;
FIG. 6 is a top plan view of the hatch opening closure member of this invention;
FIG. 7 is a bottom plan view of the annular ring of FIG. 4;
FIG. 7
a is an enlarged partial cross-sectional view taken along line 7a-7a of FIG. 7;
FIG. 8 is a bottom plan view of the hatch opening closure member of FIG. 5;
FIG. 8
a is an enlarged partial cross-sectional view taken along line 8a-8a of FIG. 8 but turned upside down;
FIG. 9 is an enlarged, partial, side elevational view of the hatch cover latch mechanism shown in its open position and disengaged from the hatch cover latching pins;
FIG. 10 is an enlarged front, perspective view of the latch mechanism showing the latch disengaged from the hatch cover latching pins and in a position to allow opening of the hatch cover; and
FIG. 11 is an enlarged, partial view of the hatch cover in its closed position with some parts shown in cross-section
DISCLOSURE OF THE PREFERRED EMBODIMENTS
FIG. 1 of the drawings shows a hatch cover 11 of this invention which can be used to close or uncover an opening 13 which is surrounded by a coaming 15 of a hopper compartment such as the type found on railroad hopper cars. As is conventional, an annular lip 17 is formed on the top of the coaming. While the coaming shown in the drawings has a turned over flange or annular lip 17, not all coamings include such an annular lip. The hatch cover of this invention may be used with convention coamings of all shapes and types. Also shown in FIG. 1 are brackets 19 which attach to the hatch cover 11 and receive a pivot pin 21. As shown in FIG. 2, additional brackets 23 attached to the coaming 15 also engage and support the pivot pin 21. Brackets 25 which are most clearly shown in FIG. 2 also attach to the coaming 15 and support a spring anchor pin 27 which can be best seen in FIGS. 9 and 10 of the drawings.
As is most clearly shown in FIGS. 1, 2, and 3 of the drawings, the hatch cover 11, which is injection molded of a suitable plastic such ABS, includes a top surface 31 having a peripheral skirt 33 depending from the top surface entirely around the periphery thereof. While injection molding using ABS is the preferred manner of manufacturing the hatch cover, it should be understood and appreciated that other materials and methods of forming the hatch cover may be used. As is shown in FIG. 3 of the drawings, radial ribs 35 are formed on the underside 37 of the hatch cover. These radial ribs merge into a center circular rib 39 also formed integrally with the underside 37 of the hatch cover. The open spaces located between the ribs 39 and the underside 37 of the hatch cover act as air flow channels between the peripheral skirt and the hopper opening 13. Additionally, a segmented annular groove 41 is formed on and integrally with the underside of the hatch cover between the radial ribs with the groove being shallower than the ribs. Bosses 43 are located in each radial rib 35 outwardly of the annular groove 41 and these bosses extend into the ribs. Holes 45 are formed in the bosses 43 to receive fasteners which will be described later. Pairs of brackets 47 are formed on and integrally with the hatch cover to receive and support latching pins 49.
An annular ring 51 formed of a suitable plastic such as ABS is shown in top plan view in FIG. 4 and in bottom plan view in FIG. 7 of the drawings. As is shown most clearly in FIG. 7a of the drawings, the ring 51 is form with outer and inner annular walls 52a and 52b defining a channel 52c. Located in the channel 52c are outer and inner ribs 52d and 52e. The outer wall 52a and adjacent rib 52d form a narrow socket 52f between them. The inner annular wall 52b and its adjacent inner rib 52e form a narrow socket 52g. Upstanding on the annular ring are pins 53 (FIG. 4) formed in a circle adjacent the inner perimeter of the annular ring. These pins fit in the annular groove 41 formed on the underside 37 of the hatch cover top member 31 as shown in FIG. 2 of the drawings. The upstanding pins are spaced apart from one another so as not to obstruct air flow through the open spaces between the ribs 35 but will block foreign objects such as leaves, twigs, etc. from reaching the hopper opening 13. Spaced openings 55 are formed in the ring outwardly of the pins 53 and fasteners 59 extend through these openings as shown in FIG. 11 of the drawings to fasten the annular ring 51 to the radial ribs 35 formed on the underside 37 of the hatch cover top member.
An annular frame 61, which is formed of a thermoplastic elastomer such as that sold under the trademark Elastocom 2860 X, is shown in top plan view in FIG. 5 and in bottom plan view in FIG. 8 and FIG. 8a of the drawings. The frame 61 which functions to seal the hopper opening 13 may be formed of other resilient, flexible materials, in addition to the thermoplastic elastomer heretofore described, such as natural rubber, synthetic rubber and flexible PVC as examples. The frame is formed with an outwardly opening channel 65, shown in FIGS. 2, 8, 8a and 11 of the drawings, defined by upstanding annular outer and inner walls or ribs 65a and 65b. The annular walls or ribs are dimensioned to fit tightly into the annular sockets 52f and 52g of the annular ring 51 as shown in FIGS. 2 and 11 of the drawings. The outer and inner walls or ribs 65a and 65b may be tapered and provided with rounded or chamfered distal ends for ease of press fitting into sockets 52f and 52g. Also formed inside of the annular frame 61 are diametrically extending runners 67 also formed of the same thermoplastic elastomer. The runners function during the injection molding of the frame 61 to flow the molten plastic from a center sprue to the outer gasket portion of the frame. Screens formed in the shape of quadrants 69 of the same material are located in the frame 61 between the diametrically extending runners. The frame 61 with quadrants 69 of screening are used for hatch covers that are vented. If it is desired to provide hatch opening with an imperforate or completely closed cover, a solid closure frame 71 shown in FIG. 6 of the drawings is used to replace the vented annular frame 61. The solid closure frame 71 is formed of the same thermoplastic material as the frame 61, but it is made with an imperforate center portion 73 replacing the screen quadrants 69.
A latch mechanism 75 shown in FIGS. 1, 2, 9, and 10 of the drawings is used to latch the hatch cover 11 in a closed position and to allow the hatch cover to be opened for loading of particulate material into a storage compartment and for replacement of the vented frame 61 or the solid frame 71, as the case may be. The latch mechanism 75 includes a latch handle 77. The latch handle is preferably made of a stamped and formed sheet of stainless steel. The latch handle may also be made of a suitable plastic or other materials such as aluminum, galvanized steel, die cast zinc, etc. The latch handle 77 has an elongated planar portion 79 with notches 81 formed intermediate the ends of the elongated planar portion, as shown most clearly in FIG. 10 of the drawings. The notches 81 define the boundary between the wider outer portion 83 and the narrower inner portion 85 of the planar portion 79 of the handle. The notches also facilitate the bending of upright members 87 on opposite sides of the inner portion 85. Outwardly opening slots 89 are formed in the ends of the uprights 87 to fit over and engage the latching pins 49 supported on the brackets 47 of the hatch cover 11. An anchor pin 91 extends between the uprights 87 and is located between the slots 89 and the wider outer portion 83 of the handle. A resilient or flexible tensioning member, in this example, a compressibly loaded helical spring 97 connects to the spring anchor pin 27 on the brackets 25 and to the anchor pin 91 on the latch mechanism 75. Such a flexible tensioning connector permits the latch handle 77 to be both installed on and moved from engagement with the latching pins 49 on the brackets 47 of the hatch cover 11. As can be seen in FIG. 1 of the drawings, an elongated depression 101 is formed in the top surface of the hatch cover to provide access to the latch handle 77 to lift it when it is in the closed position as shown in FIG. 2 of the drawings. In lieu of a depression to provide access to the latch handle 77 for unlocking the handle, parallel ribs, which are not shown, may be provided. Although it is preferred to use a compressibly loaded helical spring as the resilient or flexible tensioning member 97, it should be understood and appreciated that other materials may be used as the resilient or flexible tensioning member such as a rubber cord or strap, a PVC cord or strap or other devices such as a tension spring or even a device commonly called a bungee cord.
When it is necessary to open the hatch cover 11 from its closed position which is shown in FIG. 2 of the drawings to its fully open position, a worker reaches into the elongated depression 101 on the top surface 31 of the hatch cover as shown in FIG. 1 of the drawings to engage and lift the hatch handle 77. The worker then rotates the hatch handle 77 about the latching pins 49 on the hatch cover brackets 47 to the fully opened position of the latch handle shown in FIGS. 9 and 10 of the drawings. It is then possible for the worker to lift the hatch cover to its fully opened position while the handle 77 is maintained away from the hatch cover and supported on the spring anchor pin 27 by the compressibly loaded tensioning spring 97. In the positions of the latch handle shown on FIGS. 9 and 10 of the drawings, the slots 89 of the upright 87 of the latch handle are in a position in which they are out of engagement with the latching pins 49 of the latch cover brackets 47 so the latch handle does not interfere with the opening movement of the latch cover. When the latch handle is in its unlatched position as shown in FIGS. 9 and 10 of the drawing the hatch cover may be returned to its closed position. To lock the hatch cover 11, the slots 89 on the latch handle 77 are engaged with the latching pins 49 and the handle is rotated about the latching pins 49 until it engages the top surface 31 of the hatch cover 11 as shown in FIG. 2 to return the latch handle and the latch cover to their locked and closed positions. The tensioned connection of the latch handle 77 to the anchor pin 27 on the coaming brackets 25 and the slide-on, slide-off engagement of the open slots 89 of the latch handle 77 with the latching pins 49 of the hatch cover brackets 47 not only provides an over center locking movement for the latch handle but also provides a self adjusting locking connection between the latch handle 77 and the hatch cover 11. The provision of a tensioning connection between the hatch handle 77 and the anchor pin 27 instead of the conventional fixed pivotal connection between the latch handle and the anchor pin allows the latch handle, when in its locked position, to adjust not only for various sized hatch cover mounting arrangements of different hopper car manufacturers but also accommodates expansion and contraction of the hatch cover and its component parts, particularly the frame 61 and its gasket portion under the varying temperature conditions to which a hopper car is exposed under operating conditions.
Patent Application
20090158959
