Getting hooked

16 December 2009


A hook that can be safely handled. The assignee is Demag Cranes & Components GmbH. Technical illustration by Nick Stenning.

It features a cover region at least partially arranged between the hook tackle and the hook to cover a portion of the hook starting at the outer contour of the hook tackle.

The cover region adjoins a lower end of the hook tackle facing the hook in the manner of a ring. The load hook is composed in familiar manner of a hook to take up the load and a hook-supporting housing known as the hook tackle, by which the hook is connected to the chain.

hook

The hook tackle is divided into two halves in the lengthwise direction of the load hook and has a barrel-shaped appearance. The two halves of the hook tackle are joined together by two screws running transversely to the lengthwise direction of the hook.

In the screwed-together condition, the flat parting planes of the halves of the hook tackle lie against each other. In the region of the flat parting planes, in the lengthwise direction of the load hook, an upper and a lower recess are provided, each of which emerges through adjacent upper and lower opening regions into the top and the bottom of the hook tackle.

The load hook is form-fitted in the lower recess and the chain, via a holding piece, in the upper recess. In keeping with the barrel shaped form of the hook tackle, this load hook has a largely planar bottom side.

Cylindrical shaft

Arranged centrally in the bottom side is the opening region for the hook, especially for its cylindrical shaft. In the lengthwise direction of the hook, the outer diameter of

the load hook narrows abruptly or in step-like manner from the hook tackle to the shaft of the hook. Accordingly, the bottom side of the hook tackle is ring shaped and the shaft of the hook extends centrally outward from the bottom side of the hook tackle.

With this ring-shaped bottom side, the load hook can easily get stuck on other, primarily projecting, pieces of loads during their handling. From this position, as the chain is further slackened, the load hook can slip off and get detached, resulting in sudden loading of the hoist and a swaying of the load. Furthermore, especially in the case of rather small load hooks, the size of the hook tackle may be inadequate for an operator to grab it safely and without it slipping off when hooking on or unhooking a load or manipulating a load.

Therefore, the underlying problem solved by the invention is to create safer load hooks that can be safely handled.

According to the invention, a load hook includes a hook fastened to a hook tackle. A secure construction that is safe to handle is achieved in that a cover region is at least partially arranged between the hook tackle and the hook, such that the hook is partly covered starting at the outer contour of the hook tackle. This configuration will create a larger grasping surface for the manual holding or pulling forces applied by a user, such as when using the hands.

The larger bearing surface prevents the user’s hand from slipping off with a concomitant uncontrolled swaying of the load hook. Thus, there is less risk of injury. Furthermore, the hand cannot slip off and get injured by the step-like transition zone, since this is covered. Neither can the load hook get easily caught or stuck.

In another embodiment, the cover region adjoins the lower end facing the hook in the manner of at least a ring segment, and it covers the hook at least partly in the region of the back side of the hook, opposite the opening of the hook.

An alternative embodiment specifies that the cover region adjoins the lower end facing the hook in the manner of a ring, and also covers the hook in the region of the back side of the hook, opposite the opening of the hook. A hook mouth securement is arranged in the opening region of the hook. Thus, the handling of the hook is safe in regard to protection of the hands.

Since the user’s ball of the thumb usually grasps the back side of the hook, it is provided that the length of the cover region increases from the hook mouth securement to the back side of the hook, in the lengthwise direction of the hook. This configuration further increases the bearing surface for the hand.

Technical illustration

The load hook (1) comprises a hook tackle (2) and a hook (3). The hook tackle here has the usual function of a connection element, in order to suspend the hook (3) from a chain or cable (not shown). A design for a chain shall be assumed. The hook tackle also has a housing function, making it possible to accommodate and enclose the ends of the hook and of the chain, facing each other.

In the present embodiment of the load hook, the hook tackle is divided in the lengthwise direction L of the load hook (1), for example, in the vertical direction for a load hook hanging freely from a chain, into a first half (2a) and a second half (2b).

The partition occurs in the middle, so that the halves 2a and 2b are basically the same size. Furthermore, the halves 2a and 2b each have generally flat parting planes (4), and when assembled together they complement each other to form a barrel-shaped or cylindrical body.

In addition, the hook tackle is provided with a contoured grasping region (2c) on the outside, comprising an outwardly bulging and adjoining annular region in the lengthwise direction (L) of the load hook (1). Thus, a basically corrugated grasping region (2c) is produced. However, the valleys of the corrugation are very inconspicuous.

The grasping region (2c) is adjoined on top by an end region (2d) which, like the grasping region (2c), comprises an outwardly bulging annular region in the lengthwise direction (L) of the load hook (1). However, the end region 2d is longer in the lengthwise direction of the load hook than one annular region of the grasping region (2c).

Also, the end region (2d) has a larger diameter than an annular region of the grasping region (2c). This configuration ensures that the user’s hand grasping the load hook can feel the end of the hook tackle (2). Thus, the user can brace himself against it with his hand.

The end (2g) of the grasping region (2c) away from the end region (2d) is adjoined at the bottom by a cover region (2e), which extends in the lengthwise direction of the load hook and has the form of a sleeve-like shell. This shell, or cover region (2e), has at its upper end (2f) the approximate outer contour of the lower end (2g) of the grasping region (2c) of the hook tackle (2).

Starting at this point, the outer contour of the cover region (2e) changes in the direction of the outer contour of the hook (3), or that of a hook mouth securement (9), which is present in the region of the hook. In the present case, the cover region (2e) tapers or contracts in the direction of the outer contour of the hook. The transition between the hook or the hook mouth securement (9) and the hook tackle (2), including the grasping region (2c), thus becomes streamlined, for example, for the most part free of step-like or abrupt transitions.

Thus, because the grasping region (2c) is lengthened in the lengthwise direction of the load hook, the user’s hand can safely grasp the load hook, even in the case of a small load hook. For example, the ball of the user’s thumb can grasp the lengthened grasping region.

About the patent

US patent number 7,607,707 was awarded to Ralf Eising, Udo Gersemsky, Uwe Lichtenvort and Thilo Walloschek (the assignee is Demag Cranes & Components GmbH, of Wetter, Germany) on October 27, 2009. Application number 11/615,084 was filed on December 22, 2006.

Disclaimer

As edited versions of the originals, this article and accompanying drawing may omit legally or technically important detail.


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