Conveyors: power-driven – Conveyor for changing attitude of item relative to conveyed... – By actuating item-holder relative to holder-carrying conveyor
Reexamination Certificate
1998-09-10
2001-04-10
Valenza, Joseph E. (Department: 3651)
Conveyors: power-driven
Conveyor for changing attitude of item relative to conveyed...
By actuating item-holder relative to holder-carrying conveyor
C198S377020, C198S803700, C271S205000
Reexamination Certificate
active
06213280
ABSTRACT:
FIELD OF THE INVENTION
The present invention is related to a gripper for clamping flat articles for gripper conveyor systems or any material transport device that utilises a gripper to interface with the flat material, for instance for use in bindery equipment.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,740,900 is related to an apparatus for splitting a product stream. An apparatus for splitting a product stream includes a conveyor belt entering a folder to grip products. The conveying belt comprises first and second product grippers arranged thereon in an endless configuration. The first grippers are selectively rotatable around an axis during movement of the conveying belt to allow for secondary stream of products to be formed. The gripper design used here allows for rotational movement of any other gripper out of the formation of conveyed flat products.
U.S. Pat. No. 4,072,228 discloses an apparatus for evening an imprecated stream of printed products. This configuration comprises a number of revolving entrainment members which are a drag connection with one another. At the region of this conveying active path the entrainment members are guided and at the start of the path driven by a thrust drive and at the end thereof driven by a traction drive. The entrainment members engage the printed products and the thrust and traction drive cause a change in the spacing of the entrainment members and, consequently, in the spacing of the products.
U.S. Pat. No. 4,550,822 shows an apparatus for transporting flat products, especially printed products arriving in an imprecated formation. Printed products arriving in an imprecated product formation are fed to space gripper units of transport device by a belt conveyor. The conveying direction of the belt conveyor forms an acute angle with the transport direction of the transport device. The transporting rate of velocity of the belt conveyor is greater than the transporting rate of velocity of the transport device. Each gripper unit comprises a stationary clamping jaw, a pivotable clamping jaw and a plate-shaped stop. The pivotable clamping jaw is pivoted against the action of a clamping spring by a cam structure or the like. The printed products are first accelerated and than pushed into the open gripper mouth until abutting the stop in order to thereby align the printed products at the region of their leading edges. At the region of their trailing edges, the printed products remain under the conveying action of the belt conveyer and at least until the gripper units are closed.
Existing designs which use springs to provide the gripping force do not allow both, a high gripping force and a large gripper jaw travel due to size and stress constrains on the spring. In addition, current latching gripper designs are prone to turn open and are sensitive to wearing of the latch parts.
SUMMARY OF THE INVENTION
In view of the prior art discussed it is accordingly one object of the present invention, to have a compact gripper having both a high gripper force and a large gripper jaw travel.
A further object of the present invention is to prevent a gripper from unintended turning open.
A still further object of the present invention is to provide a gripper which is less sensitive to component wear.
According to the present invention, a gripper comprises
a stationary gripper member,
a gripper member being relatively movable towards said stationary gripper member,
and a pretensioned actuating member extending through the stationary and the movable gripper members, respectively,
said pretensioned actuating member having cam surface portions being contacted by contacting members causing the gripper members to close upon removal of external forces.
The present invention offers several advantages over the latching mechanisms known in the art. A latching mechanism subject to wear and tear is completely eliminated, thus the reliability of the gripper actuating mechanism is significantly enhanced. The compact design of the gripper according to the present invention allows for aligning a large number of grippers in a conveying chain along a conveying track. Since the gripper is actuated by components, the surfaces of which are sliding with respect to each other, those surfaces can be treated by hardening; moving parts such as levers subject to wear can be eliminated completely.
According to further details of the present invention the stationary gripper member comprises a rotating lever for rotating movement of the stationary gripper with respect to the conveying direction along a conveying track. Said gripper comprises a conveying support to which on both sides thereof rollers are mounted to facilitate movement of the gripper according to the present invention along a conveying track. Further, a gripper support according to the present invention comprises connecting links for a chain-like arrangement of the grippers along a conveying track.
A stationary gripper member comprises a hollow interior within which a pushing member and a supporting members are mounted. Said pushing and said supporting members are mounted for relative movement towards each other which in turn causes the relative movement of both gripper members with respect to each other. The pushing member is pretensioned by a spring means such as a package of cup springs or a single cup spring or a package of helical springs or a single helical spring, depending upon the various production requirements such as gripper forces or gripper opening forces respectively. Still further, the spring means used for pretensioning the pushing member could be constituted by a gaseous medium.
The supporting member can be mounted to the movable gripper member, whereas the pushing member is encapsulated by the stationary gripper member. Both members may comprise upper and lower actuating means, respectively. Those could be rollers or roller bodies subjected to a hardening surface treatment. Said actuating means are mounted in recesses of said pushing or supporting member respectively. Those recesses have a diameter equal to the diameter of the roller bodies, in order to secure the roller bodies respective positions and locations.
Between the actuating means mounted in both the pushing and the supporting member, respectively, and cam surface portions of the plunger means extending through the pushing member and the supporting member, contacting members are journaled. Upon movement of the plunger means in vertical direction, said contacting members force the pushing member and the supporting member in opposite directions with respect to each other. This is achieved by having the cam surface portions of the plunger means have a different angle of inclination.
The present invention further discloses a method for actuating a gripper between a closed and an opened position. Contacting members contact lower cam surface portions of an actuating means such as a plunger and roller body surfaces of roller bodies of pushing and supporting members in a closed position. Said contacting members contact upper cam surface portions of an actuating means such as a plunger and surfaces of roller bodies of pushing and supporting members in an open position.
REFERENCES:
patent: 3671035 (1972-06-01), Reist
patent: 3726389 (1973-04-01), Klein et al.
patent: 3955667 (1976-05-01), Muller et al.
patent: 4072228 (1978-02-01), Honegger et al.
patent: 4550822 (1985-11-01), Meier
patent: 4982944 (1991-01-01), Eberle
patent: 5380000 (1995-01-01), Ohno
patent: 5740900 (1998-04-01), Cote et al.
patent: 0 312 755 (1989-04-01), None
Abbadessa Stephen Edward
Curley Richard Daniel
Sharkady Matthew Thomas
Burns Doane , Swecker, Mathis LLP
Heidelberger Druckmaschinen AG
Valenza Joseph E.
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