Patent Application
20060064853
The present invention relates to metal, fiber, plastic shipping and storage drums and containers and other applications such as transformer cases, etc. in which split closing rings of various diameters are utilized to secure a lids or covers. It is more specifically concerned with improvements in the lever closing device of the split ring.
Lever closing devices are commonly used to reduce the effective diameter of a closing ring about a cylindrical container and through compression secure a cover or other related assembly on open head drums or other containers and similar enclosures. In some applications, such as shipping containers, the force resulting from actuating the closing device lever is used in conjunction with a gasket placed between the cover and container to seal the interface encircled by the closing ring. Typically the lever is secured in the closed position by a secure clip which may be separate or attached to either the closing device or closing ring. This secure clip holds the closing device lever in the closed position by affixing the lever to the closing ring or lever attachment arm of the closing device.
Generally lever closing devices are attached to the ends of the split closing ring via a series of resistance welds or rivets on the lever and pivot attachment arms. Commonly, three attachment points are used on the lever attachment arm, including the secure clip for riveted devices, while two are used on the pivot attachment arm. All resistance welds are typically made simultaneously while rivets are installed two at a time or individually.
In the prior art riveted lever closing device two rivets each are used to attach the lever and pivot attachment arms to the closing ring. An additional rivet is used to attach the secure clip to the closing ring. The spacing of the secure clip rivet point relative to those of the lever and pivot attachment arms requires excessive movement during riveting. Different rivet depth settings for the rivets used to attach the lever and pivot attachment arms and that used to attach the secure clip are also required. Further, the odd number of rivets (5) requires that the rivets either be installed in five individual operations using a single rivet machine or in three operations using a double rivet machine in conjunction with a single.
In a welding process, the number and asymmetric nature of the weld points on the lever and pivot attachment arms also complicate the welding process by causing an unequal welding-current distribution between the welding points. Relatively small variations in closing ring diameter make adjustment of the welding process problematic.
The secure clip is generally inserted through slots in the sides of the closing device lever and a loop located on the lever attachment arm to hold the lever in the closed position. The lever is weakened by and sometimes fails (bends) at these slots due to the compressive forces of closing. Each of the forgoing deficiencies highlights the need for an improved ring closure mechanism.
It is the object the present invention to improve the usefulness and reliability of the lever closing device by simplifying the attachment of the closing device to the closing ring and reducing the failure rate of the closing device lever during operation.
A further object of the invention is to reduce the overall cost of the lever device and its attachment to the closing ring.
Each of the foregoing objects and other advantages are accomplished in the invention through an improved lever attachment arm which utilizes closely spaced, symmetric attachment points and eliminates the requirement for slots through the sides of the closing device lever. In the case of riveting, the design of the lever-attachment arm minimizes rivet depth settings and operator movement by eliminating the requirement for a rivet affixing the secure clip to the closing ring. In the case of welding, symmetric closely spaced weld projections result in a more equal distribution of welding currents with less welding power input. The weld projection spacing utilized on the improved lever attachment arm has the additional advantage of simplifying the tooling required to weld the lever-closing device to the closing ring. The invention has the additional benefit of reducing the material content and forming steps required for the Secure Clip.
These and other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment of the invention.
An improved lever closure embodying the features of the present invention is depicted in the accompanying drawings which form a portion of this disclosure and wherein:
Referring to the drawings for a clearer understanding of the prior art and the invention it may be seen from
The lever closing device, depicted in
In an alternate embodiment of the present invention it has been found possible to mount secure clip 32 to the pivot arm 41 and form lateral slots 42 in the pivot arm such that the pivot arm would be latched to tab 34 in the closed position. In this embodiment The secure clip would then engage the pivot arm slot or slots 42 and slot 36 to secure the lever in the closed position. This embodiment can be seen in
It is to be understood that the forms of the invention shown is a preferred embodiment thereof and that various changes and modifications may be made therein without departing from the spirit of the invention or scope as defined in the following claims.
