Patent Application
20070024063
This invention relates generally to hatch covers and, more particularly, to methods and apparatus for securing a hatch cover in a locked position.
Railroad cars generally have one or more compartments for storing and transporting materials. Each compartment is generally provided with one or more openings or hatch ports. Hatch ports are provided for loading the compartment with product and are usually located at the top of the compartment. Hatch ports usually have a circular cross-sectional shape and are frequently provided with a collar extending outwardly about the periphery of the hatch port. A hatch cover is provided to close or seal the hatch port.
Known hatch covers are hinged at one side so as to pivot about a first axis, such as the horizontal axis. A latch assembly is mounted to the collar of the hatch port for securing and locking the hatch cover to the collar. With at least some known latch assemblies, a worker manually closes the hatch cover onto the collar to close the hatch port. The worker then rotates a lever of the latch assembly so that a portion of the lever extends over the hatch cover and prevents the hatch from lifting off the hatch port.
To tighten the fit between the hatch cover and the collar of the hatch port, a worker typically rotates the lever about a second axis, such as the vertical axis, before rotating the lever onto the hatch cover. In some known latch assemblies, the lever is rotated about the second axis to either tighten or loosen a screw for adjusting the distance between the lever and the hatch cover.
After adjustment of the distance between the lever and the hatch cover, the worker rotates the lever while the lever bears against the hatch cover, from an unlocked position in which the lever does not contact the hatch cover to a locked position in which the lever contacts and bears against the hatch cover. A separate tool may be required to tighten the latch assembly and center the lever before the lever is rotated into the locked position.
In one aspect, a method for securing a hatch using a latch assembly is provided. The hatch is sized to cover a hatch port extending outwardly about an opening in a vessel. The latch assembly has a cam member and a bolt member, wherein the cam member has a cam lever portion and a clevis portion, and the bolt member has a first axis extending between a first end and a second end. The first end is hingedly attached to the hatch port about a second axis that is generally perpendicular to the first axis, and the second end is in a threaded relationship with a securing member. The clevis portion is configured to be rotationally engageable with the securing member about the first axis. The method includes positioning the latch assembly relative to the hatch by rotating the latch assembly about the second axis, engaging the securing member with the clevis portion of the cam member, rotating the lever portion of the cam member about the first axis to adjust the threaded relationship between the securing member and the bolt member, and pivoting the lever portion towards the hatch until the lever arm is in a locked position for securing the hatch to the hatch port.
In another aspect, a hatch cover assembly for covering an opening in a vessel is provided, wherein a hatch port extends outwardly about the opening. The hatch cover assembly includes a hatch cover hingedly attached to the hatch port, and at least one latch assembly for fastening the hatch cover to the hatch port. The latch assembly includes a cam mount extending from the hatch port, and a first cam pin coupled to the cam mount. The first cam pin has a pin axis. A bolt member includes a first end and a second end, and the bolt member has a centerline axis extending between the first end and the second end. The centerline axis is generally perpendicular to the pin axis, and the first end is hingedly attached to the first cam pin about the pin axis. A securing member is in threaded relationship with the bolt member second end. The securing member is rotatable about the centerline axis of the bolt member. A cam member includes a cam lever portion and a clevis portion. The cam member is coupled to the bolt member by the securing member, and the cam member is configured to engage the securing member and adjust the threaded relationship of the securing member with respect to the bolt member by rotating the lever portion about the centerline axis of the bolt member.
In a further aspect, a latch assembly is provided including a cam mount having a first cam pin extending therethrough, and a cam shaft having a first end and a second end. The cam shaft has a centerline axis extending between the first end and the second end. The first end includes an opening for receiving the first cam pin and for securing the cam shaft to the cam mount, and the second end includes a threaded portion for threaded engagement with a securing member. A cam member includes a lever end, a clevis end and a cam member axis extending therebetween. The second end of the cam shaft extends substantially perpendicular through the clevis end. The clevis end has an opening including an engagement portion sized to receive the securing member and the securing member is configured to couple the cam member to the cam shaft. The engagement portion is rotationally engageable with the securing member about the centerline axis for adjusting the threaded relationship between the cam shaft and the securing member.
The car 20 includes a frame 22 having a side sill 24 mounted on conventional trucks 26, a pair of opposed side walls 28 extending upwardly from the side sill 24, a pair of opposed end walls 30 extending upwardly from the side sill 24, and a top 32 supported by the walls 28 and 30. A plurality of compartments 34 for storing particulate material being transported are defined by the side sill 24, side walls 28, end walls 30, and top 32. Additionally, in one embodiment, compartments 34 are further defined by a trapezoidal shaped bottom (not shown) for directing material to a discharge opening (not shown). In another embodiment, compartments 34 may have a conical shaped bottom or other shape that facilitates directing material contained within the compartments to a discharge opening.
Hatch assembly 10 includes a hatch cover or hatch 42 having a top surface 44, and an access port or hatch port 46 (shown in
Hatch 42 has a shape and size that is sufficient to cover hatch port 46 with which it is associated. As shown in
In the exemplary embodiment, latch assembly 40 includes a wear plate 50 that is mounted on top surface 44 of hatch 42. In one embodiment, hatch 42 and wear plate 50 have a u-shaped cutout, and wear plate 50 is made from a durable material such as, for example, stainless steel. A cam mount 52, such as a pair of brackets, extend substantially perpendicular from hatch port 46. A first cam pin 54 is rotationally mounted to cam mount 52 about a pin axis 56 that is generally horizontal and/or parallel to railroad car top 32 where latch assembly 40 is mounted.
Latch assembly 40 includes a cam shaft 62, also referred to hereinafter as a bolt member. Cam shaft 62 has a base portion 64 and a threaded portion 66. Base portion 64 includes a bore 68 that is generally aligned with cam mount 52. Base portion 64 is pivotally connected to first cam pin 54 for rotation about pin axis 56. A centerline axis 70 extends between a first end 72 and a second end 74 of cam shaft 62. In the exemplary embodiment, base portion 64 is positioned proximate first end 72, and threaded portion 66 is positioned proximate second end 74.
Latch assembly 40 includes a securing member 80, such as, for example, a nut, which is coupled in a threaded relationship with bolt member threaded portion 66. Accordingly, the position of securing member 80 along bolt member 62 is adjustable along centerline axis 70. In one embodiment, centerline axis 70 is substantially perpendicular to pin axis 56. In the exemplary embodiment, securing member 80 has a plurality of corners, such as a hex-nut, and a plurality of sidewalls extending between the corners. In the exemplary embodiment, securing member 80 restricts movement of a cam member 82 in a direction that is generally away from first cam mount 52. As such, when latch assembly 40 is positioned over wear plate 50 and top surface 44 of hatch 42, securing member 80 restricts movement of cam member 82 away from hatch 42. Additionally, as securing member 80 is adjusted along threaded member 66 relatively closer to bolt member base portion 64, cam member 82 facilitates sealing hatch cover 42 with respect to hatch collar 48. In one embodiment, a motion limiting feature (not shown) is included to restrict removal of securing member 80 from bolt member 62. For example, a stopper (not shown) is coupled to second end 74 of bolt member 62, such as, for example, by a welding process. The stopper is configured to resist removal of securing member 80 from bolt member 62 and is intended to provide a “tamper-resistant” or “tamper-evident” hatch assembly 10.
As illustrated in
In operation, second cam pin 88 facilitates hingedly or pivotally coupling clevis portion 86 of cam member 82 to bolt member 62 such that lever portion 84 of cam member 82 may be pivoted between an unlocked and a locked position (an example of which is illustrated in
In the example embodiment, clevis portion 86 also includes an opening 92 (shown in
In one embodiment, opening 92 has an engagement portion 94 configured to mate with securing member 80 for rotational movement of securing member 80 about the centerline axis 70 of bolt member 62. Specifically, engagement portion 94 interfaces with securing member 80 when cam member 82 is in the engagement position. This allows cam member 82 to adjust the threaded relationship between securing member 80 and threaded portion 66 for adjusting the distance between cam member 82 and hatch 42. For example, by adjusting the securing member 80 in a direction towards base portion 64 of bolt member 62, cam member 82 will be positioned relatively closer to hatch 42, thus increasing the biasing force of cam member 82 on hatch 42 when cam member is in the locked position. However, engagement portion 94 does not interface with securing member 80 when cam member 82 is in the neutral unlocked position, and thus, cam member 82 is moveable with respect to securing member 80 when cam member 82 is in the neutral unlocked position. For example, cam member 82 may be moved in the following directions in order to reposition cam member 82 with respect to securing member 80. Cam member 82 is movable in a rotational direction around centerline axis 70 extending through bolt member 62. Cam member 82 is movable in a rotational or pivotal direction around second cam pin 88. However, cam member 82 may be movable in other directions as well.
In the exemplary embodiment, engagement portion 94 is defined by opposed sidewalls 96 extending into opening 92. Sidewalls 96 are positioned on a bottom side of cam member 82 (i.e., the portion of cam member 82 positioned proximate hatch 42 when cam member 82 is in the locked position). When cam member 82 is in the locked position, engagement portion 94 is generally opposed to securing member 80. As a result, cam member 82 may be rotated the approximately 180 degrees or otherwise manipulated to move cam member 82 to the engagement position and thus engage securing member 80 with engagement portion 94 of cam member 82. In the exemplary embodiment, sidewalls 96 of engagement portion 94 are spaced apart a distance slightly greater than a distance between opposed sidewalls of securing member 80. As such, sidewalls 96 are configured to engage the sidewalls of securing member 80 for rotating securing member 80 upon rotation of cam member 82.
In other words, an exemplary method of use for hatch assembly 10 involves a user transferring cam member 82 from the locked position, in which securing member 80 bears against cam member 82 such that cam member 82 secures hatch 42 in a closed position, to an unlocked position. The user accomplishes this by rotating or pivoting lever portion 84 about second cam pin 88 to the neutral unlocked position. By transferring cam member 82 from the locked position to the unlocked position, the user can then rotate hatch 42 from hatch port 46 to allow access to compartments 34.
If, however, the user wishes to tighten or loosen the seal (i.e., a gasket) between hatch 42 and hatch collar 48, the user, after transferring cam member 82 from the locked position to the unlocked position, continues to rotate or otherwise manipulate cam member 82 to position cam member 82 into the engagement position. In the engagement position, engagement portion 94 of cam member 82 engages securing member 80 and cam member 82 is used to ratchet securing member 80 to either tighten or loosen securing member 80 with respect to bolt member 62. Specifically, securing member 80 may be rotated about bolt member 62 to adjust the position of securing member 80 along threaded portion 66 of bolt member 62. In operation, as securing member is moved relatively closer to base portion 64 of bolt member 62, cam member 82 is also moved relatively closer to hatch 42, thus tightening the locking force of cam member 82 on hatch 42. As securing member 80 is moved relatively away from base portion 64 of bolt member 62, cam member is also moved relatively away from hatch 42.
Moreover, to secure hatch 42 to hatch collar 48, cam member 82 is rotated about pin axis 56 until cam shaft 62 is substantially vertical and within u-shaped cutout, as shown in
Once securing member 80 is positioned on bolt member 62, cam member 82 is rotated to a position that is substantially centered with hatch 42 and pivoted about second cam pin 88 to the locked position. Adjusting the position of cam member 82 by adjusting the depth of securing member 80 with respect to bolt member 62 eliminates the need for an additional tool such as a ratchet or wrench normally carried by a user and utilized to adjust the position of cam member 82.
Once the desired position of cam member 82 and securing member 80 is achieved with respect to bolt member 62, cam member 82 is further pivoted about a bottom portion 98 of cam member 82 towards top surface 44 of hatch 42. Bottom portion 98 bears against wear plate 50 as cam member 82 is rotated from an unlocked position in which the lever portion 84 does not contact top surface 44 of hatch 42 to a locked position in which lever portion 84 is positioned along top surface 44 of hatch 42, as shown in
To open hatch 42 to gain access to hatch port 46, each latch assembly 40 must be rotated from the locked position to the unlocked position. Once each latch assembly 40 is moved to the unlocked position and rotated away from hatch 42, hatch 42 may be opened to allow access to hatch port 46.
In other words, the position of securing member 80 with respect to bolt member 62 is adjusted to tighten or loosen the seal between hatch 42 and hatch collar 48. Cam members 82 may be operated and hatch covers opened and closed without engaging securing member 80. Securing member 80 and engagement with clevis portion 86 of cam member 82 allows for gasket sealing adjustments with cam member 82 in lieu of a person having to carry a tool to the top of a railcar for such adjustment.
Secondary latch 102 functions as a safety feature when opening hatch 42. For example, secondary latch 102 secures hatch 42 to hatch port 46 when cam member 82 is rotated from the locked position to the unlocked position. In other words, when cam member 82 is rotated from the locked position to the unlocked position, secondary latch 102 prevents hatch 42 from a forced opening which may result from compartments 34 being under pressure. Only upon removal of secondary latch 102 can hatch 42 be opened. In the exemplary embodiment, secondary latch 102 includes a pivoting arm assembly 104 pivotally mounted to first cam pin 54. Pivoting arm assembly 104 is rotated about pin axis 56 between a locked and unlocked position.
In operation, to secure hatch 42 to hatch port 46, pivoting arm assembly 104 is rotated on first cam pin 54 and secured along top surface 44 of hatch 42. Once pivoting arm assembly 104 is positioned, cam member 82 can be rotated from the unlocked position to the locked position. As such, secondary latch 102 provides a safety feature for hatch 42.
In addition, as described above, the depth of securing member 80 can be adjusted using clevis portion 86 of cam member 82 to tighten or loosen the seal between hatch 42 and hatch collar 48.
The above-described latch assembly is a cost effective and efficient means to secure a hatch cover over an opening in a vessel. The latch assembly includes a recess in the cam member for rotational engagement of a securing member without a separate tool. The latch assembly also allows for centering the cam member with respect to the top surface of the hatch before rotating the cam member into a locked position. As a result, the latch assembly facilitates adjusting the cam shaft without an extra tool in a cost-effective and time-saving manner.
Exemplary embodiments of a latch assembly are described above in detail. The systems are not limited to the specific embodiments described herein, but rather, components of each assembly may be utilized independently and separately from other components described herein. Each latch assembly component can also be used in combination with other latch assembly and hatch assembly components.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
