Material or article handling – Vertically swinging load support
Reexamination Certificate
1998-07-23
2001-01-09
Morse, Gregory A. (Department: 3652)
Material or article handling
Vertically swinging load support
C414S749400, C414S223020, C029S740000, C198S339100
Reexamination Certificate
active
06171049
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method for the cycled receiving, placing and depositing of a preferably flat subject on an operating station, in particular on a chip loading automatic machine. With this for example chips must be removed from a wafer or a magazine arranged in the receiving plane and with a high precision and with great speed deposited on an underlay lying in the dispensing plane in a cycled manner.
The receiving plane and the dispensing plane may at the same time be arranged parallel and possibly may also lie in the same plane. The placing path should however be as small as possible and the masses to be accelerated should likewise be small. By way of the company document Alphasem AG, CH-8572, Berg, Switzerland a method and a device of a comparable type has become known in which the receiving plane and the dispensing plane are arranged at right angles to one another. A pivoting arm with a single receiving head carries out a 90° pivoting movement and with this transports chips from a rigidly clamped wafer to underlays which are led past in a cycled manner. The cycle speed may be increased with this arrangement compared to other transfer units.
A disadvantage of all known methods and devices however lies in the fact that the subjects over the whole placing path are always grasped on the same side and with this do not change their relative position to the transfer unit. At the same time a position change during transport or even a turning of the flat subject about 180° is not possible. In certain areas of application, in particular in electronics it would however be desirable to deposit the subject with the upper side face down.
SUMMARY OF THE INVENTION
It is therefore the object of the invention to provide a method of the previously mentioned type with whose help on covering the placing path, selectively a relative position change of the subject is possible. In particular on a chip loading automatic machine the dies removed from a wafer should be able to be deposited with the active side face down (flip-ship). According to the invention this object is achieved with a method as described hereafter.
The subdividing of the placing path into two different placing cycles permits the subject at the intermediate station arranged in the region of the placing path to change its position, in particularly to turn completely. Since the gripping means grips the subject essentially laterally the upper side and the lower side of the subject remain free in order to grasp it. By way of the simultaneous transport of a subject from the receiving plane to the intermediate station and from the intermediate station to the dispensing plane no time is lost in spite of the two-cycle advance.
For a certain operating method the subject is gripped on the upper side at the receiving plane and transported to the intermediate station. At the intermediate station it is flipped over and gripped on a lower side in order to be deposited with the upper side on the dispensing plane. Of course it is however also conceivable to grip the subject again on the upper side and with this to leave it in the same position, or where appropriate by turning about any spacial axis to bring it only into a somewhat different angular position which is more advantageous for the further transport and/or for the depositing on the dispensing plane. Advantageously the subject independently of its relative position at the intermediate station, in its relative position with respect to the dispensing plane, is displaced forwards between a receiving position in which the subject is clamped and a dispensing position in which the subject is dispensed. By way of this the course of movement can be simplified and the intermediate station does not have to be arranged exactly at half the path of the placing path.
Preferably the subject at the intermediate station is held by way of a pneumatically activatable clamping device with which flexible tubing sections for clamping are inflated and for releasing are contracted. In this manner without danger of damage also very thin components may be exactly held. Annoying gripping jaws or likewise do not occur so that the whole surface of the subject remains free on both sides. According to the nature of the subject it is of course also possible to hold this at the intermediate station by way of clamping jaws. These clamping jaws may grasp the subject in various ways and they may be motorically driven or also activated with other means, such as e.g. electromagnetically, by heat expansion, etc.
The invention also relates to a device for the cycled receiving, placing and depositing of a flat subject, as described herafter. In contrast to the known devices the transfer unit is equipped with two operating heads, specifically each with a receiving head and with a depositing head. The receiving head has the purpose of transporting the subject from the receiving plane to the intermediate station and the depositing head fetches the subject from here and transports it to the dispensing plane, wherein the subject at the intermediate station may be selectively changed in its lateral position. This separation into two operating heads has additionally also the advantage that the heads only have to cover very small distances.
The intermediate station is rotatably and/or pivotably mounted about any spacial axis such that the subject on an upper side can be gripped with the receiving head and clamped into the gripping means and that on a lower side it can be gripped with the depositing head and removed by the gripping means. With this the intermediate station is preferably rotatably mounted on a pivoting lever about a rotational axis. The pivoting lever axis at the same time is connected to the rotational axis by a gear in a manner such that on pivoting the pivoting lever the rotational axis selectively stands still or rotates. By way of these relatively simple mechanics the intermediate station in the course of a pivoting movement of the pivoting lever may be moved in a manner such that the pivoting movement is compensated and the subject still assumes the same relative position even at the end of the pivoting movement. If on the other hand the rotational position is fixed, the clamped subject co-pivots and in this manner changes its relative position.
Alternatively to the geared connection of the pivoting lever to the rotational axis the intermediate station may of course also be moved via a separate drive, for example via an electric motor arranged directly at the intermediate station or via a pneumatic drive.
The gripping means on the intermediate station advantageously comprise at least one flexible contact surface which can be inflated under pressure for grasping the subject and which can be contracted under a vacuum for releasing the subject. The gripping means may at the same time comprise two support profiles arranged at a distance wherein the flexible contact surfaces are formed by tubing sections which are slid over the support profiles. Alternatively one side of the gripping means may be formed as a rigid abutment in order to achieve a defined positioning. There further results a particularly useful arrangement when the support profiles on one side are fastened onto a holder, when the tubing sections are in operating connection with a cavity in the holder and when the holder is rotatable about a rotational axis which is formed as a hollow axis and via which the cavity may be connected to a pressure source or a vacuum source.
In order to keep the transport path as small as possible the receiving plane and the dispensing plane are inclined at an angle of preferably 90° to one another. With this the transfer unit is formed as a pivoting arm on which in the same pivoting plane, the receiving head and the dispensing head are angularly displaced to one another. Such an arrangement of the planes however would not be possible in all cases of application. It is therefore conceivable without further ado for the receiving plane and the dispensing plane to run parallel to one another,
Forster Martin
Wirz Gustav
Alphasem AG
Morse Gregory A.
Shoemaker and Mattare Ltd.
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