Cassette and handling system

An embodiment of the invention provides a cassette comprising a top plate, a base plate, a plurality of posts arranged between the top plate and the base plate and defining an operation space, a securing device comprising a stop mechanism and a clamping mechanism and arranged along with one post. The stop mechanism comprises a stop projection provided on an outer side of the one of posts, a stop bar parallel to the one post and slidable disposed through the stop projection, and a stop block disposed on a side of the stop bar. A lower end of the stop bar extends beyond a plane of the base plate when the stop block is bearing against an upper surface of the stop projection. The clamping mechanism comprises a first connection part with a rotation shaft in a middle portion of the first connection part being fixed to the one post and with one end connected with the stop bar in a transmission way, and a securing portion, which connects with the other end of the first connection part and is driven by the first connection part to move horizontally with respect to the one post when an up-and-down movement of the stop bar leads to rotation of the first connection part.

BACKGROUND

The present invention relates to a cassette and a handling system having the same.

Recently, liquid crystal displays (LCDs), especially thin film transistor liquid crystal displays (TFT-LCDs), as a kind of flat panel displays, are increasingly becoming popular. In a LCD, a color filter substrate and an array substrate which are assembled together are essential parts for manufacturing a LCD. Both of the substrates are made by using a thin glass plate as a base. During manufacturing a LCD, unprocessed glass plates, processed glass plates, or assembled panels are always needed to be carried to somewhere. Especially, during manufacturing an array substrate (thin film transistor substrate), there are a number of processes, which each involve some apparatuses of different functions, for example, a processing apparatus for processing the plates and carrying apparatus for loading and/or unloading the plates, and so on.

In a conventional method, a cassette is often used as an apparatus for storing and carrying glass plates. Such a cassette100is shown inFIG. 1, which comprises a top plate101and a base plate102with posts103arranged between the top plate101and the base plate102. The posts103are arranged on three sides of the plates101and102so as to define a space for operation, leaving one side open for handling glass plates200. Support beams104are arranged on the inner side of the posts103facing the inside of the cassette100and supporting the glass plate200thereon, and the support beams104may be a single beam connected between two opposite posts103or a short bar projected from the side of each post103, respectively, as long as they can support the glass plate200thereon. In operation, the cassette100usually cooperates with a handling desk300. The handling desk300comprises a base platform301for placing the cassette100and a recess for picking up and/or placing of the cassette100with an apparatus such as a forklift. The handling desk300is usually fixed to the ground beside the processing apparatus. After the cassette100is carried and placed on the handling desk300, the glass plates200housed in the cassette100can be picked up and placed on the processing apparatus for further processing.

The cassette may be typically provided with a plurality of support beams at different levels, so that glass plates can be placed on the support beams at different levels and carried between various processing apparatuses simultaneously. That is, the glass plates housed in a same cassette can be carried and processed together until they become finished products after various steps, thus improving productivity. Therefore, during processing, storing and carrying, the several glass plates in the same cassette can be regarded as a whole.

However, during transporting or carrying, vibrations and unexpected shakes give rise to a degree of position offset for the glass plates. The position offset may accumulate among the processions so that the glass plates may go beyond the bounds of processing, bringing about mismachining tolerance. The cassette of the above design is designed only for the purpose of loading and unloading glass plates and can not adjust the position of the glass plates even if there is position offsets of the glass plates. In order to cope with the problem, a position adjustment device is provided for the glass plates in the processing apparatus and brings a limited position adjustment for the glass plates before processing. Generally, such position adjustment device is incorporated into a carrying robot, a carrying apparatus, or the processing apparatus as an additional apparatus such as a pusher or a clamper, intending to keep the position offsets of the glass plates within the bounds of processing.

In order to clearly show the position offsets of the glass plates during transporting, experiments have bee made. Table 1 shows a set of experiment data, which denotes the measured values of the position offset of the glass plates during three long distance transportations of the cassette.

In Table 1, entries A, B, C and D represent the measured values of the distance between the edge of the glass plates200and the edge of the cassette100at LA, LB, LC, and LD, respectively, as shown inFIG. 2, and the numbers following A, B, C and D represent the times of transportation, respectively; the sequence numbers in the column correspond to the glass plates in the cassette, and the less the number, the lower the corresponding glass plate is positioned in the cassette.

The above table records the accumulated position offsets at the four measuring sites for each of the twenty glass plates carried in the cassette. The unit of the position offset in the table is millimeter (mm). The table shows that the glass plates tend to shift to the outside of the cassette, and the glass plates at different levels have different position offsets. Furthermore, the table shows a phenomenon that some glass plate may experience a relative bigger “jump” after a certain transportation, which makes the glass plate shift outside of the position adjustment capability of the processing apparatus and accordingly may result in an industrial accident.

Thus, it needed to reduce the position offsets during the transportation of the glass plates, especially, in manufacturing a LCD.

SUMMARY

An embodiment of the invention provides a cassette comprising a top plate, a base plate, a plurality of posts arranged between the top plate and the base plate and defining an operation space, a securing device comprising a stop mechanism and a clamping mechanism and arranged along with one post. The stop mechanism comprises a stop projection provided on an outer side of the one of posts, a stop bar parallel to the one post and slidable disposed through the stop projection, and a stop block disposed on a side of the stop bar. A lower end of the stop bar extends beyond a plane of the base plate when the stop block is bearing against an upper surface of the stop projection. The clamping mechanism comprises a first connection part with a rotation shaft in a middle portion of the first connection part being fixed to the one post and with one end connected with the stop bar in a transmission way, and a securing portion, which connects with the other end of the first connection part and is driven by the first connection part to move horizontally with respect to the one post when an up-and-down movement of the stop bar leads to rotation of the first connection part.

Another embodiment of the invention provides a handling system comprising a cassette and a handling desk for supporting the cassette thereon. The cassette comprises a top plate, a base plate, a plurality of posts arranged between the top plate and the base plate and defining an operation space, and a securing device comprising a stop mechanism and a clamping mechanism and arranged along with one post. The stop mechanism comprises a stop projection provided on an outer side of the one of posts, a stop bar parallel to the one post and slidable disposed through the stop projection, a stop block disposed on a side of the stop bar. A lower end of the stop bar extends beyond a plane of the base plate when the stop block is bearing against an upper surface of the stop projection. The clamping mechanism comprises a first connection part with a rotation shaft in a middle portion of the first connection part being fixed to the one post and with one end connected with the stop bar in a transmission way, and a securing portion, which connects with the other end of the first connection part and is driven by the first connection part to move horizontally with respect to the one post when an up-and-down movement of the stop bar leads to rotation of the first connection part.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment of Cassette

FIG. 3is an illustrative view of a structure of a first embodiment of a cassette according to the present invention. The cassette100comprises a top plate1001and a base plate102with a plurality of posts103arranged between the top plate101and the base plate102. The posts103are arranged on three sides of the plates101and102so as to define a space for operation, leaving one side open for handling a glass plate200. A plurality of support beams104are arranged on the inner side of the posts103facing the inside of the cassette100and supporting the glass plate200thereon, and the support beams104may be a single beam connected between two opposite posts103or a short bar projected from the side of each post103, respectively, as long as they can support the glass plate200thereon. The cassette100is further provided with two securing devices110, which are arranged along with respective posts103on two opposite sides of the cassette100.

Each securing device110is provided along with one post103and comprises a stop mechanism and a clamping mechanism as shown in detail inFIG. 4. Specifically, the stop mechanism comprises a stop projection111provided on an outer side of the post103and having a vertical through hole, a stop bar112parallel to the post103and slidable disposed in the vertical through hole so that the stop bar112can move up and down with respect to the stop projection111(that is, the post103) in the through hole, and a stop block113disposed on a side of the stop bar112and over the through hole. The size of the stop bar matches that of the through hole, and the stop block113extends beyond the size of the through hole and can be pressed against the upper surface of the stop projection111so as to limit the downward movement of the stop bar112but not limit upward movement of the stop bar112. Therefore, the lower end of the stop bar112can extend beyond the plane of the base plate when the stop block113is pressed against the upper surface of the stop projection111, and the lower end of the stop bar112extending beyond the plane of the base plate can act as a sensing probe. The clamping mechanism comprises a first link lever114, a second link lever115, and a securing portion. The first link lever114, that is, a first connection part, has a rotation shaft in a middle portion thereof that is fixed to a side of the post103. An end of the first link lever114facing the outside of cassette is connected with the stop bar112in a transmission way, and in this embodiment, the end of the first link lever114is connected with the stop bar112via the second link lever115, namely a second connection part. The lower end of the second link lever115is hinged with the stop bar112with a first hinge121, and the middle portion of the second link lever115is hinged with the outer end of first link lever114with a second hinge122so that the first and second link levers114,115are able to rotate with respect to each other. The securing portion116is hinged with the other end of the first link lever114facing the inside of the cassette100with a third hinge123. The first link lever114drives the securing portion116to move horizontally with respect to the post103, and the up-and-down movement of the stop bar112in turn leads to rotation of the first link lever114. The hinge connections between the above parts have shafts parallel with each other, and thus the parts can rotate in a same plane.

In operation, the securing device of the embodiment can perform two actions, i.e., a releasing action and a clamping action, which are introduced below, respectively.

The releasing action can be realized in the following case. The cassette100is placed on a plane such as a handling desk or the ground, and at that time, the lower end of the stop bar112is located on a same plane as the base plate102, so that the stop block113does not bear against the upper surface of the stop projection111; at the same time, the upward movement of the stop bar112leads to an upward movement of the first hinge121between the second link lever115and the stop bar112, the second link lever115then brings the second hinge between the first and second link lever114,115to move upward and thus to rotate. Since the rotation shaft in the middle portion of the first link lever114are immovable, the upward movement of one end of the first link lever114causes rotation of the first link lever114about the shaft and the other end thereof goes downward with respect to the post103. The securing portion116moves horizontally with respect to the post103, that is, approaches the post103, due to the drop of the inner end of the first link lever114. After such position adjustment of each securing device110, the distance between the two securing device that are facing each other increases, in other words, the cassette100is in a releasing state and is ready for housing glass plates200therein.

After glass plates200is placed into the cassette100, and when the cassette100is carried by an apparatus such as a forklift and thus is lift from the plane, the clamping action begins to work. After the cassette is lift up, the stop bar112drops by gravity since the lower end of the stop bar112is free, and the stop bar112drops until the stop block113bears against the upper surface of the stop projection111. Also, when the stop bar112drops, the second link lever115, first link lever114, and the securing portion116act in a way opposite to that in the releasing action when the stop bar112goes up, and therefore, the securing portion116moves horizontally away from the post103, the distance between the two securing device facing each other decreases, in other words, the cassette100shifts to a clamping state, clamping the glass plate200therein.

The lower end of the stop bar112bears against a platform when the cassette100is paced on the platform after the cassette100is carried to a predetermined position, and at this time, the cassette100performs the release action again so as to release the glass plates200therein for picking up.

In the embodiment, positions of the hinges between the parts are not limited to an end or middle portion as those mentioned above but may be anywhere as long as the hinges enable the elements to rotate in a same plane. The position relationship between stop mechanism and clamping mechanism has no influence on their functions.

The cassette of present embodiment can clamp and fix the glass plates in place with simple structure and thus prevent position offsets of the glass plates with the securing device during transportation. Furthermore, the securing device can automatically release the glass plates for loading and unloading when the cassette is placed on the platform. Thus, this embodiment prevents the position offset of the glass plate with simple structure, low cost for reconstruction, and automatic operation of releasing and clamping actions of high reliability.

Second Embodiment of Cassette

FIG. 5is an illustrative view of a structure of a securing device in a second embodiment of the cassette according to the present invention. The second embodiment is modified based on the first embodiment. A first spring positioning pillar118is disposed on a side of the post103; a second spring positioning pillar119is disposed on a side of the stop bar112above the first spring positioning pillar118; a spring117is also provided with two ends thereof being attached to the first spring positioning pillar118and the second spring positioning pillar119, respectively.

In the first embodiment, the stop bar drops by gravity. However, in the transportation, the shock of the glass plates applies a force on the securing portion which may in turn pulls the stop bar up when the force is transmitted to the stop bar. The spring117of the present embodiment which is incorporated in on the basis of the first embodiment can resist the force and thus ensure the stop bar in a lowest position to clamp the glass plates in place during transportation.

The connection of the spring117between the post103and the stop bar112in the second embodiment is not limitative, which may be any form as long as only it enables the spring to pull down the stop bar112until the stop block113bears against the upper surface of the stop projection111.

Third Embodiment of Cassette

FIG. 6is an illustrative view of a structure of a securing device in a third embodiment of the cassette according to the present invention. The third embodiment differs from the first embodiment in that there are several clamping mechanisms provided between the post103and a corresponding stop bar102, the securing portions116of which is integral (the same one) and thus forms a integrated securing post, and a first elastic pad120, which may be sponge or rubber, for preventing wear to the glass plates200caused by direct contact of the securing portion116and for reducing compact due to the shock of the glass plates200, is provided and connected to the inner side of the securing portion116facing the inside of the cassette100.

In the embodiment, the securing portion is an integrated securing post, which can clamp the glass plates in the cassette in place at the same time. Alternatively, the securing portions of the securing device may be independent to each other, each for holding one corresponding glass plate. If the glass plates in the cassette are of different sizes, it is also possible to set the lengths of the portions of the first link levers between the securing portions and the posts to different sizes respectively to fit with the sizes of different glass plate.

The securing device of the cassette according to preset invention may be provided along with the posts at only one side of the cassette and cooperate with the posts at another side (opposite side) of the cassette to actively clamp the glass plates form one direction. Alternatively, the securing devices can be provided along with the posts at the opposite sides of the cassette and clamp the glass plates form both the opposite directions. One securing device may be provided along with one post at one side of the cassette; alternatively, more than one securing device may be provided along with more than one respective post. Further more than one securing device may be provided along with one post. The position and the amount of the securing device as necessary. The securing device may be made of a metal or a plastic material, as long as it can meet the strength required to clamp the glass plates.

In the embodiment of the cassette according to the present invention, the connection between the first link lever and the stop bar is not limited to the form as shown inFIG. 4, and there may be various alternatives. For example, the shaft of the first link lever may be parallel to the post, in which case the rotation of the first link lever can still move the securing portion close to or away form the post, while the first link lever and the stop bar are arranged in such a way that the up and down movement of the stop bar can be transformed into the rotation of the first conductive level. For example, the up and down movement can be transformed into the rotation of the rotation shaft of the first link lever via a threaded spindle, thus realizing the horizontal movement of the securing portion with respect to the post.

First Embodiment of Handling System

FIG. 7is an illustrative view of a structure of a first embodiment of a handling system according to the present invention. The handling system comprises a handling desk300and a cassette100that may be one of the exemplary cassettes mentioned above. The handling system, also referred to as a cassette indexer, comprises a base platform301for supporting the cassette thereon. The cassette100comprises a top plate101and a base plate102with a plurality of posts103arranged between the top plate101and the base plate102and defining a space for operation. The cassette100is also provided with at least one securing device, which comprises a stop mechanism and a clamping mechanism. Specifically, the stop mechanism comprises a stop projection111provided on a side of the post103facing outside, a stop bar112parallel to the post103and slidable disposed in a through hole of the stop projection111, and a stop block113disposed on a side of the stop bar112. The lower end of the stop bar112extends beyond the plane of the base plate when the stop block113is bearing against the upper surface of the stop projection111. The clamping mechanism comprises a first link lever114, a second link lever5, and a securing portion. The first link lever114has a rotation shaft in a middle portion thereof that is fixed to a side of the post103. An end of the first link lever114facing the outside of cassette is connected with the stop bar112in a transmission way, and the end of the first link lever114is connected with the stop bar112via the second link lever115, namely a second connection part. The lower end of the second link lever115is hinged with the stop bar112with a first hinge, and the middle portion of the second link lever is hinged with the outer end of first link lever114with a second hinge so that the first and second link levers114,115are able to rotate with respect to each other. The securing portion116is hinged with the other end of the first link lever114facing the inside of the cassette100with a third hinge. The first link lever114drives the securing portion116to move horizontally with respect to the post103, and the up-and-down movement of the stop bar112in turn leads to rotation of the first link lever114.

The cassette in the present embodiment of the handling system can act as above described along with the first embodiment of the cassette, and the handling system can comprise a handling desk with a base platform for supporting the cassette thereon and cooperating with the cassette.

The handling system of present embodiment can clamp and fix the glass plates in place with simple structure and thus prevent position offsets of the glass plates with the securing device of the cassette during transportation. Furthermore, the securing device can automatically release the glass plates for loading and unloading when the cassette is placed on the platform. Thus, this embodiment prevents the position offset of the glass plate with simple structure, low cost for reconstruction, and automatic operation of releasing and clamping actions of high reliability.

The cassette of the handling system according this embodiment may be any one embodiments of the cassette described above. Specifically, the securing device of the cassette comprises the first connection part with one end connected to the stop bar via a second connection part, which hinges to the stop bar and the first connection part, respectively, and the other end that hinges with the securing portion, and the rotation shaft and the shafts of all the hinges are parallel to each other.

Further, a spring may connect the post and the stop bar, which can pull down the stop bar until the stop block bears against the upper surface of the stop projection. There may be more than one clamping mechanism connected to each post103and a corresponding stop bar102, the securing portions of which is integral and thus forms an integrated securing post. Lengths of the first link levers connected between the securing portions and the posts may be in different sizes as necessary. The amount of the securing device can be determined as necessary. At least one securing device may be connected to at least one post on two opposite sides of the cassette. Furthermore, a first elastic pad may be further provided and connected to the inner side of the securing portion facing the inside of the cassette. The securing device may be made in metal or plastic materials.

Second Embodiment of Handling System

FIG. 8is an illustrative view of a structure of a second embodiment of the handling system according to the present invention. The handling desk300of the handling system comprises a base platform301, four positioning levers302vertically arranged on the base platform301at four corners for defining a region for placing the cassette on the base platform301. That is, the cassette100(details of which is not shown inFIG. 8) is placed among the four positioning levers302. At least one pair of rotational arms303are provided on each of the positioning levers302. Each rotational arm is an arcuate lever, and each pair of rotational arms are oppositely arranged and can cooperate with each other to close and open when rotating about the positioning lever302in a same horizontal plane. In such a way, ends of each pair of the rotational arms303cooperate with each other to clamp the glass plates200placed in the cassette100.FIG. 9is an illustrative view of a state of the second embodiment of the handling system according to the present invention with the rotational arm in a closed state. A second elastic pad304that is made in sponge or rubber for preventing wear to the glass plates200is provided on the end of each rotational arm303. Further, each pair of rotational arms303are further coupled to a control means (not shown) for controlling the aspects of rotation of the rotational arms303, including torque, velocity and/or angle of the rotational arms303.

The operation of the embodiment of the handling system is described below. The cassette100carrying the glass plates200are moved away from the handling desk300, the stop bar112drops until the stop block113bears against the upper surface of the stop projection111so that the lower end of the stop bar112extends beyond a plane of the lower surface of the cassette, and the securing device110moves due to the drop of the stop bar302to clamp the glass plates200in the cassette100. The control means is driven to rotate the rotation arms303to an open position as shown inFIG. 10, in which the rotation arms303are opened to receive the cassette100in the region defined by the positioning levers302, and then the cassette100is placed on the base platform in the region with the vertical edges each being positioned adjacent to the respective positioning lever302. At that time, the lower end of the stop bar112moves upward until flushing with the plane of the base plate of the cassette100, and the upward movement of the stop bar112leads to the movement of the securing portion116of the securing device110so as to release the glass plates200. As shown in theFIG. 9, the rotational arms303are rotated to a close position for clamping the glass plates200under the control of the control means. When a glass plate is needed, the rotational arms303are driven to the open position for unloading of the glass plate.

In the embodiment, there are four positioning levers, but there may be two positioning levers arranged in positions adjacent to two opposite vertical edges respectively, that is, at two corners diagonally. The rotational arms on the two positioning lever can rotates and clamp the glass plates therebetween so as to adjust the position of the glass plates.

The handling system of the embodiment can prevent the position offset of the glass plates actively during transportation with the securing device of the cassette, and can further adjust the position of the glass plates through the rotational arms on the handling desk. The position of the glass plates depends on the rotational position of the rotational arms, whose rotational angle and velocity and rotation procedure of the rotational arms may be controlled by the control means such as a PLC or an industrial computer. The positioning levers of the handling desk may be provided with a pair of the rotational arms for each glass plate, so that four corners of the glass plate can be clamped by the rotational arms. Shape and amount of the rotational arms may be determined as necessary as long as the rotational arms can cooperate with each other so as to clamp and rotate the glass plates. The handling desk of the handling system in the present embodiment has a relative big adjustment range, thus industrial accidents due to the limited adjustment of the position adjustment means in the processing can be avoided. Also, this further eliminates the risk of industrial accidents due to the position offset of the glass plates and increases working efficiency and product quality.