Screw conveyor having linked latch closure

A conveyor includes a container and a cover. A plurality of upper latches each include an upper hook. A plurality of lower latches each include a lower hook. A plurality of brackets are fixedly attached to the container and are disposed along the container, where each bracket is configured to pivotally support each lower latch at a pivot point. A rigid linkage member couples the body portion of each lower latch. Urging in a first direction at any point along linkage member causes each lower hook to simultaneously disengage from the upper hook to unlock the cover. The pivot point is arranged such that the weight of the body portion and the linkage member cause the lower hooks to be urged against the upper hooks to lock the cover to the container, in the absence of a force applied to the linkage member in the first direction.

BACKGROUND

1. Technical Field

The present disclosure relates generally to a latching mechanism used in coverings for screw conveyor systems.

Screw conveyor systems are often used in the food processing industry to move food products, such as meat products, along an enclosed pathway from either an initial loading point or a first food processing machine, to a destination point or a second food processing machine. The screw conveyor system includes a box or container, having a cover, and a screw or auger located toward the bottom of the container and arranged along the length of the container. Food product entering the input end of the container is transported along the length of the container as the screw rotates, and exits the output end of the container. The cover prevents the food product from being forced out of the container, and also facilitates sanitary handling of the food product and compliance with industrial safety regulations.

Food processing personnel must often open the cover of the container to perform various operations, such as inspecting the conveying process, verifying proper operation and movement of the food product, adding ingredients, and periodically cleaning the device. Screw conveyor covers can be held closed in many different ways. Known covers are typically not sufficiently stiff to remain tightly closed along their entire length with only a single latch. Accordingly, some known conveyors use a plurality of latches disposed along the length of the cover. In such systems, each latch must be disengaged separately to open the cover. Frequently, one or more of these latches can be difficult to access because there may be external objects that impede easy and convenient access to the latches, thus more time and effort is needed to perform the basic operation of opening the cover. Other known latches require a moderate amount of force to release, such as “cam-over” latches or “vise-grip” type latches.

SUMMARY

In one embodiment, multiple latches are disposed along the length of the cover as part of a single integrated structure that facilitates opening the cover from any convenient location along its length, without having to manually disengage each latch separately. The plurality of latches, in one embodiment, are designed with a hook type interface that locks the cover to the opening of the container. In one specific embodiment, the center of gravity of the linked latches is offset so as to retain the latches in a “down” or locked position, which permits the cover to remain locked when no external force is applied to the mechanism. The latches are also easily engaged by simply closing the cover. The latches have a hook type interface that locks the hooks together when the cover is closed.

In another embodiment, a screw-type conveyor includes one or more containers, each having an open portion and a cover configured to cover the open portion. A plurality of upper latches are disposed in a spaced relation along a length of the cover, where each upper latch has an upper hook. Similarly, a plurality of lower latches are disposed in a spaced relation along a length of the container, where each lower latch has a lower hook, a body portion, and a pivot point disposed between the lower hook and the body portion. A plurality of brackets are fixedly attached to the container and are disposed in a spaced relation along the length of the container, where each bracket is configured to pivotally support the corresponding lower latch at the pivot point. A rigid linkage member couples the body portion of each lower latch. Urging in a first direction at any point along linkage member causes each lower hook to simultaneously disengage from the upper hook so as to unlock the cover from the container. Conversely, the pivot point is arranged such that a weight of the body portion and the linkage member cause the lower hook to be urged against the upper hook and engage the upper hook to lock the cover to the container, in the absence of a force applied to the linkage member in the first direction.

DETAILED DESCRIPTION

Referring toFIGS. 1 and 2,FIG. 1illustrates a single container segment100of a screw-type conveyor110, whileFIG. 2illustrates screw-type conveyor110inclined at an operational angle. The conveyor110may operate from the horizontal position to a near vertical position. Typically, the conveyor110may be about 3 feet to 20 feet in length, and a maximum length of each separate container segment100may be about 9 feet. Multiple container segments may be concatenated. However, any suitable segment length may be used, and the length of the entire conveyer110may be greater than 20 feet depending upon the application.

Referring now toFIGS. 3 and 4,FIG. 3shows a container segment100of the screw conveyor110with a cover116shown in an open position.FIG. 4shows the container segment100of the screw conveyor110with the cover116in a closed position. Each container segment100includes a container120or other suitable enclosure, and the corresponding cover116. As more clearly shown inFIG. 3, the container120has a bottom portion302and a trough306formed in a bottom portion302of the container120. A transport screw310or auger may be disposed in the trough306of the container120, which may extend along a length of the container120. Rotational power to the transport screw310is provided by a motor (not shown). In operation, food product, such as meat for example, may be loaded at an input end320of the container. Food product deposited at the input end320of the container is transported along the length of the container120as the screw310rotates, and exits an output end326of the container120. The cover116prevents the food product from being inadvertently forced out of the container120, and also facilitates sanitary handling of the food product and compliance with industrial safety regulations.

FIGS. 5 and 6show a latching mechanism500in greater detail. Portions of the latching mechanism500may be disposed on both a side wall506of the container120and the cover116of the container120to facilitate locking the cover116to the container120and unlocking the cover116from the container120. The latching mechanism500may include a plurality of upper latches512disposed in a spaced relation along a length of the cover116, where each upper latch512may have an upper hook516. For purposes of clarity, only three of the upper latches512are shown in the figures, but any suitable number of such latches maybe used for each container segment100, depending on the length of the container. Generally, the longer the container120, the more latches512are needed to adequately secure the cover116. Similarly, a plurality of lower latches520may be disposed in a spaced relation along the length of the container120, where each lower latch520may have a lower hook526, a body portion528, and a pivot point530disposed between the lower hook526and the body portion528. The number of upper latches512are preferably equal to the number of lower latches520for a one-to-one correspondence.

Further, a plurality of brackets536may be fixedly attached to the container120and may be disposed in a spaced relation along the length of the container120. Such spacing between the brackets536may be equal or unequal depending on positional, functional, and aesthetic considerations. The brackets536may be fixed to the container120by known methods, such as by welds, screws, nuts and bolts, rivets, or other suitable fasteners. Preferably, each bracket536may pivotally support a corresponding lower latch520a pivot point530. A handle544affixed to the cover permits the cover116to be manually lifted when the latching mechanism500is disengaged.

A rigid linkage member546or rod may fixedly couple the body portion528of each lower latch520and may extend from lower latch to lower latch and across all lower latches520. As may be clearly understood viewing the arrangement ofFIG. 5, urging the linkage member546in a first direction, such as in an upward direction at any point along the length of linkage member546, as shown by the upwardly directed arrow550, will cause the lower hooks526to simultaneously rotate about the pivot point530and simultaneously disengage from the upper hooks516so as to unlock the cover116from the container120and permit manual (or spring-loaded assist) raising of the cover116.

Each lower latch520may pivot about the pivot point530and may be supported by the bracket536. The lower latches520may be attached to the corresponding bracket536with a suitable fastener556received though an aperture in the lower latch520and bracket536, such as by a nut and bolt, or any suitable fastener that permits the lower latch520to rotate freely relative to the bracket536. Further, the pivot point530is arranged such that the weight of the body portion528and the linkage member546cause the lower hooks526to be urged against the upper hooks516and engage the upper hooks to lock the cover116to the container120in the absence of a force applied to the linkage member546in the first direction550. Essentially, the configuration of the metal components are weighted in a specific direction relative the pivot point530so that the latching mechanism500tends to rotate clockwise into the locking position absent an external force applied to the latching mechanism500.

As shown inFIGS. 5-6, a downwardly directed arrow560shows the affect of gravity on the position of the lower latches520due to the weight distribution of the lower latches520and the linkage member546, in conjunction with the center of gravity of the lower latches520.

FIGS. 5-7illustrates a stop or projection702disposed on a portion of the bracket536, formed, in one embodiment, as a bent portion of the bracket536extending out of a plane of the bracket536, and configured to contact a portion of the body portion528. The stop702prevents further rotation of the lower latches520about the pivot point530when rotating toward the closed and locked portion. For purposes of cost and ease of manufacturing, the stop702may be integrally formed with the bracket526, but alternatively may be a separate component affixed to the bracket536.

As shown inFIG. 8, the upper hook516includes an engagement surface802disposed at a predetermined angle. Similarly, the lower hook526includes a corresponding engagement surface804disposed at substantially the same angle. The angle shown relative to horizontal is preferably about 20 degrees but may range from about 15 degrees about 25 degrees.

Note that in some embodiments, the latch mechanism500does not exert any positive pressure on the cover116, assuming no food product inside the container120is pushing against the cover. Accordingly, the cover116does not need to seal tightly or be hermetically sealed because most of the food products being conveyed is usually fairly large in size and cannot escape a small gap between the cover116and the container120. In other words, the chamber formed by the container120is not “pressurized” in any way. In one specific example, if the angle of 20 degrees shown inFIG. 8between the hook engagement surfaces802,804is maintained, then a gap of about 5/64 inch (0.075) will exist between the cover116in the surface edge of the container where the cover meets the container. This gap is provided so that the hooks515,526of the latch will clear each other during rotation.

Of course, when passively operated, there will be no gap between the cover116and the top edge of the container120, and the cover will rest positively against the container. However, internal forces within the container120caused occasionally by food product bumping against the inside of the cover could tend to momentarily bump the cover116away from the container120by a small distance mentioned above until the engaged upper hooks516prevent further upward movement of the cover116, essentially “locking” the cover in place. The hook engagement surfaces802,804may be formed at any suitable angle depending upon the acceptable small gap that would necessarily exist between the cover116and the container120.

FIG. 9illustrates the position of the upper latches512and the lower latches520when the cover116is desired to be opened. An upward force is applied to the linkage member546by pulling up on the linkage member. This causes the lower latches520to pivot in a counterclockwise direction, thus disengaging the lower hooks526from the upper hooks516. The cover116may then be lifted by the separate handle540located at a convenient place on the cover116. With the cover116open, the linkage member546may be released, and under the force of gravity, the lower latches520will rotate in a clockwise direction until the body528of the lower latches520contact the stop702disposed on the bracket536. Such upward force may be applied by a hand of a person to the linkage member546in preparation for lifting the cover116away from the container120. The upward force may be applied anywhere along the linkage member546. Of course, an operator may lift up on the linkage member546using two hands spaced apart, but such extra effort is not needed, and the latching mechanism500will release regardless of where the upward force is applied along the linkage member.

FIGS. 10A-10F, illustrate the position of the components when the cover116is lowered from the open position to the closed position.FIG. 10Ashows the cover116in an open position. Consequently, the lower latches520, under their own weight, are fully rotated in a clockwise direction with the body portions528resting against the stop702of the brackets536. InFIG. 10B, the cover116is lowered and an upper or first strike surface1004of the upper hook516makes initial contact with a lower or second strike surface1008of the lower hook526. Due to the angle of contact, the upper hook516forces the lower hook526to move away thus causing the lower latches520to pivot in the counterclockwise direction (as viewed in the figures). InFIG. 10C, further rotation of the lower latch520occurs and the cover116is lowered as the first strike surface1004slides further along the second strike surface1008. As shown inFIG. 10D, tips1012of the upper hook516and the lower hook526are in contact. InFIG. 10E, the tips1012of the hooks have passed each other, and the lower latch520is now able to begin clockwise rotation.FIG. 10Fshows that the lower latch520has rotated fully in the clockwise rotation and is in the locked position.

Note that the components forming the upper latches512and lower latches520may be juxtaposed in position so that the upper latches512, which are fixed in nature, are disposed on container, while the lower latches520with its pivoting action are disposed on the cover116, and still retain the principles and features discussed herein.

For example, in such an alternate embodiment the fixed or non-moveable plurality of latches512may be affixed to the side of the container, while the pivoting latches520ganged together by the linkage member546may be disposed on the cover116. In such a configuration, the linkage546member may function to rotate the latch out of engagement with its counterpart and also may provide a handle with which to lift the cover upwardly.

Although movement of the linkage member546referred to as movement in the first direction may appear to be an upward direction as shown in the drawings, however, in other embodiments, such first direction may be a downward movement depending on whether the linkage member546is placed forward of the pivot point530or backward of the pivot point along a body portion of the latch.