Conveyors: power-driven – Conveyor section – Unit load conveying surface means moved about an endless or...
Patent
1991-07-08
1993-01-12
Olszewski, Robert P.
Conveyors: power-driven
Conveyor section
Unit load conveying surface means moved about an endless or...
1984701, 271204, B65G 4786
Patent
active
051782626
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to clamping tongs for chain conveyors.
An apparatus of such character is known, for example, from Swiss Pat. No. 644,816. In this apparatus, retention of the movable clamping jaw in its closed position is effected by means of a pawl coupling. To this end, a ratchet wheel is non-rotatably connected with the movable clamping jaw. A spring-biased pawl, which is pivotable in the housing, engages the ratchet wheel in the locking position. The drawback of this apparatus is its complex design and also the fact that it is necessary to actuate two different levers in order to open and close the clamping tongs. A corresponding apparatus according to published European patent application No. 241,631, wherein a coil spring lock is provided in lieu of the pawl coupling, is not less complex regarding its design and its operation.
OBJECT OF THE INVENTION
An object of the present invention is to provide clamping tongs which can be used in chain conveyors of the aforementioned type and wherein locking of the movable clamping jaw in its closed position, as well as its opening, are effected by a simple mechanism without additional springs, actuating levers and other complex parts.
SUMMARY OF THE INVENTION
In accordance with the invention, this object is accomplished with the characteristic features of the patent claim 1.
The novel clamping tongs exhibit the advantage that, after having moved beyond the dead-center point of pivoting of the lever, the closing force of the springy force transmitting element which connects the lever with the movable clamping jaw locks the lever in that end position which corresponds to closed position of the movable clamping jaw. For such purpose, the dead-center mechanism for the lever requires only a small number of simple elements, for example, a discrete shaft for the lever as well as a toggle joint or a locking cam in combination with the lever.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 a plan view of a first embodiment of the novel clamping tongs with a toggle joint, the clamping tongs being shown in the closed position;
FIG. 2 a side elevational view, partly in section, of the clamping tongs of FIG. 1 but in their closed position;
FIG. 3 a side elevational view, partly in section, of the clamping tongs of FIG. 1 in their closed position according to FIG. 1;
FIG. 4 a plan view, partly in section, of a second embodiment of the novel clamping tongs with a locking cam, the clamping tongs being shown in their closed position;
FIG. 5 a side elevational view of the clamping tongs of FIG. 4 but in their open position according to FIG. 4; and
FIG. 6 a side elevational view of the clamping tongs of FIG. 4 in their closed position according to FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
As shown in FIGS. 1 to 3, the illustrated clamping tongs comprise a substantially rectangular box-shaped housing 1 which is open at its upper side and consists of a plastic material. The external active elements of the clamping tongs are constituted by a clamping jaw 4 which is secured to the bottom 2 of the housing by screws 3, a pivotably movable clamping haw 5, and an actuating lever or actuator 6. The plate-like clamping jaws 4 and 5 are shown broken away in FIG. 1 for the sake of clarity. The screws 3 can simultaneously serve to secure the clamping tongs to a non-illustrated chain conveyor. In order to be actuatable by an external part, the lever 6 is provided with a roller 7.
The lever 6 is pivotably mounted on a shaft 8 which is disposed in the housing 1, namely in a corner recess 9 of the housing 1 (FIG. 1). The lever 6 has two arms and that arm 10 which is located opposite the roller 7 is provided with an extension 11 which abuts the inner side of the bottom 2 in the closed position of the clamping tongs (FIG. 3) to thus limit the pivotal movement of the lever 6 about the shaft 8 in one direction of pivotal movement and forms part of a motion transmitting unit. Furthermore, the arm 10 of the lever is provided with a nose 12 which has a bor
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Eugster Albert
Merkli Peter
Oppliger Jean-Claude
Bidwell James R.
Grapha-Holding AG
Kontler Peter K.
Olszewski Robert P.
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