Handling: hand and hoist-line implements – Grapple – Slideable jaws
Reexamination Certificate
1999-03-22
2001-05-22
Cherry, Johnny D. (Department: 3652)
Handling: hand and hoist-line implements
Grapple
Slideable jaws
C294S902000, C414S751100
Reexamination Certificate
active
06234550
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates, in general, to an apparatus for retrieving and depositing a load, e.g. from a rack or onto a rack, and more particularly to a load pick-up apparatus of a type having a grabbing device with grippers moveably guided in parallel elongated guides for travel in a horizontal plane into an operative position in which the grippers are positioned on both sides next to confronting side walls of the load, and urged into engagement with the confronting side walls.
German Pat. No. DE 196 13 707 describes an apparatus which includes lance-like grippers for retrieving and depositing load units, whereby the grippers can be moved in a horizontal plane for disposition on both sides next to the side walls of the load unit. The grippers are guided in elongated guides and pivoted in synchronism in opposite direction into a clamped engagement with the side walls of the load unit. After effecting the clamped engagement with the load unit, the load can be retrieved by retracting the grippers to thereby remove the load unit form the storage area. A depositing of the load unit for storage is effected in analogous fashion.
A drawback of this conventional grabbing device is the relative small contact area of the grippers so that the grippers may cause damage to the load, in particular when cardboard boxes are involved. Moreover, the effective contact pressure applied by the grippers must be sufficiently great to ensure a safe removal and storage even when the load unit is charged.
SUMMARY OF THE INVENTION
It is thus an object of the present invention to provide an improved apparatus for picking up and depositing a load, obviating the afore-stated drawbacks.
In particular, it is an object of the present invention to provide an improved load pick-up and depositing apparatus which operates at relatively small contact pressure while still assuring a secure retrieval and placement of the load, without damage to the container.
These objects, and others which will become apparent hereinafter, are attained in accordance with the present invention by providing a pair of elongated guides in parallel disposition, and a grabbing device with at least two grippers which are movably guided in the guides for travel in an operating direction from a ready position to an operative position in which the grippers are disposed on both sides of the load substantially parallel to the sides of the load, with each gripper having at least one plate-shaped gripping area, with the gripping areas of both grippers opposing one another in parallel relationship and in substantial parallel relationship with respect to the side walls of the load unit, and whereby the elongated guides are movable in synchronism toward one another to thereby force the grippers into engagement against the sides of the load unit.
The grabbing device according to the present invention has grippers which are forced in parallel alignment against the load and thus can be designed with a sufficiently large gripping area that enables to keep the contact pressure relatively small while still assuring good gripping behavior of the grippers. Moreover, as the synchronized movement of the grippers is realized via the elongated guides the load unit can be securely grabbed, even when the load unit is misaligned to a certain extent.
Suitably, the gripping area of the grippers may have a roughened surface to realize a better force fit. The gripping action can be further enhanced, in particular when soft containers are involved, by providing the gripping area of the grippers with serrated vertical indentations.
According to another feature of the present invention, each gripper has two plate-shaped vertical bearing surfaces which extend perpendicular to the gripping area in the direction of the opposite gripper and face away from one another. Thus, the load unit rests against the confronting one of the bearing surfaces, to thereby ensure, in particular during placement for storage, a secure shifting of the load unit into a proper position.
According to still another feature of the present invention, each gripper has at least one further gripping area, with the bearing surfaces of each gripper defining in the operating direction a leading bearing surface, whereby one of the gripping areas is positioned in the operating direction ahead of the leading bearing surface. In this manner, two racks in confronting parallel disposition can be loaded and unloaded, without requiring any complex maneuvers, as it is only necessary to reverse the operating direction, i.e. the leading bearing surface in one operating direction becomes the trailing bearing surface in the other operating direction, and vice versa. This configuration ensures that in either operating direction, a bearing surface engages the load unit being maneuvered.
It is also possible to provide two gripping areas ahead of and behind the bearing surfaces to better conform the pick-up apparatus to different packagings, such as plastic containers or cardboard boxes. Suitably, the two gripping areas are arranged in succession when viewed in the operating direction to thereby ensure a trouble-free operation during loading for storage and retrieval. In order to realize a safe grabbing of plastic containers as well as cardboard boxes, one of the two gripping areas has serrated vertical indentations and the other gripping area has a roughened surface. Suitably, the serrated gripping area has a thickness which is smaller than the thickness of the roughened gripping area. In this manner, different strength properties of the load units are taken into account.
According to another feature of the present invention, the gripping area of each gripper may have arranged thereon at least one arbor-like projection which extends perpendicular to the gripping area toward the opposing gripper, to thereby realize a secure grabbing even when cardboard boxes are handled. Suitably, the arbor has a length which is greater than the thickness of the roughened and serrated gripping areas.
According to yet another feature of the present invention, a synchronized motion of the elongated guides can be realized via an interconnecting spindle which is driven by a motor and has opposite ends which are rotatably supported in the elongated guides. Suitably, the drive for the spindle is operatively connected to one spindle end, while the other spindle end is received in a spindle nut which is securely fixed in the associated elongated guide. The drive may be a servomotor for cost-saving purposes. The contact pressure of the grippers upon the load unit may be restricted to a maximum value by automatically stopping operation of the servomotor when a predetermined motor current value is exceeded.
A synchronized movement of the elongated guides can be realized in a simple manner by providing a double lever which is rotatably supported in a frame at a central location with respect to the elongated guides and hingedly connects the elongated guides to one another.
REFERENCES:
patent: 2740540 (1956-04-01), Lindsey
patent: 2921701 (1960-01-01), Ireland
patent: 4284381 (1981-08-01), Minato
patent: 4305692 (1981-12-01), Brauer
patent: 4735452 (1988-04-01), Nemoto
patent: 5271706 (1993-12-01), Helbach et al.
patent: 5449262 (1995-09-01), Anderson et al.
patent: 5588688 (1996-12-01), Jacobsen et al.
patent: 33 24 349 C1 (1984-11-01), None
patent: 91 01 201 U (1992-02-01), None
patent: 44 25 127 A1 (1996-01-01), None
patent: 196 13 707 A1 (1997-10-01), None
patent: 0 733 563 (1996-09-01), None
patent: 2 246 119 (1992-01-01), None
Schatz Uwe
Stoltenhoff Karl-Wilhelm
von Schneidemesser Christian
Cherry Johnny D.
Feiereisen Henry M.
Mannesmann AG
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