GB2059924A - Feeding sheets - Google Patents

Abstract

An apparatus for transferring sheet-like objects includes a magazine for a stack of objects supported above a reciprocable table incorporating object attraction and repulsion means which are operable on movement of the table away from under the magazine to attract an object thereto such that it is removed from under the stack past a restrictor means ensuring only the lowermost object is removed to a take- off position from whence it is removed when the repulsion means are actuated said means being mounted in operation during the return movement of the table. Preferably the attraction and repulsion means are pneumatic, but they may be electromagnetic or electrostatic. <IMAGE>

Description

SPECIFICATION Apparatus for transferring sheet-like objects The present invention concerns apparatus for transferring sheet-like objects, for example paper sheets from one location, for example a stack of said sheets to another location, one sheet at a time.

The present invention has many applications but one particularly suitable application is in the decoration of glass or ceramic ware with decalcomanias (decals). Normally these decals include a design layer supported on a substrate which usually comprises a paper layer, an intermediate layer being formed between the design and paper layers to permit the separation of the design layer from the paper layer immediately prior to use. The intermediate layer may be a water soluble layer or a layer which melts when a relatively high temperature is applied thereto, or a pressure sensitive layer decals of these types being referred to as "water release", "heat release" or "pressure release" respectively.

In the automated decoration of ware it is desirable to provide a supply of decals which are automatically fed one at a time to the ware to be decorated and it will be realised that the position of the decal on the ware is critical. Thus it is essential that the means for transferring the decals from the supply is positionally precise. In the past it has been found that providing a roll of paper with decals supported thereon has been most successful but this arrangement has numerous disadvantges, for example it is expensive to produce and results in relatively complex transfer mechanism in the automated decorating machine.

It is an object of the present invention to obviate or mitigate these disadvantages.

According to the present invention there is provided an apparatus for transferring sheet-like objects, including a magazine with guide means adapted to receive and support a stack of sheet-like objects, a transfer table at one end of said magazine, means for moving said table laterally of the magazine, object attraction and repulsion means incorporated in the table and take-off means for removing objects from the table.

Preferably the magazine is arranged above the table such that the stack therein is fed towards the table by gravity. The means for moving the table may include a reciprocable piston and cylinder device and the object attraction and repulsion means incorporated in the table may comprise a plurality of perforations selectively connectable to a source of under atmospheric pressure air and a source of above atmospheric pressure air.

The guide means of the magazine preferably comprise stop means for limiting the movement of the bottom sheet-like object of the stack in a direction opposite to that from which it is removed from the stack by the transfer table.

Arranged at the side of the magazine opposite from said guide means may be located a restrictor positioned above the top surface of the table at such a distance that it permits only one object to pass thereunder at a time. Conveniently the restrictor is a threaded member supported by mounting means above the table for movement towards or away from the table.

The take-off means conveniently comprises a pad movable relative to the table and provided with object attraction means which are conveniently a series of perforations selectively connectable to a source of under atmospheric pressure air.

One embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 shows an elevation of a transfer apparatus; Figure 2 shows a view of the apparatus from above; Figure 3 shows a sectional elevation on the line Y-Y of Figure 1 and Figure 4 shows, in plan, a take off means.

A transfer apparatus comprises a framework 10 supporting two spaced parallel guide bars 12 which in turn, by means of bushes 14, slidably support a transfer table 16. The transfer table is of hollow construction and comprises a flat top plate having a plurality of perforations formed therethrough.

Means, (not shown) are provided for selectively connecting the interior of the table with a vacuum source or a compressed air source and this connection incorporates valve means operable to supply compressed air to the interior of the table when it is moving from right to left (in Figure 2 of the drawings) and a vacuum when it is moved from left to right. A pneumatic piston and cylinder device 18 is connected between the framework 10 and the table 16 and actuation of the piston and cylinder device 18 results in movement of the table 16 along the bars 12.

A magazine 20 for decals having a card-like substrate is supported on the framework 10 above the table 16, its lower end facing the upper surface of the table. The magazine has a fixed back face 22 the lower edge of which is spaced as closely as possible to the upper surface of the table 16, for a reason to be described below. Further, it is preferable that the side faces 24 of the magazine are also fixed and spaced as closely as possible to the upper surface of the table 16. The front face 26 of the magazine is spaced above the upper surface of the table by an amount greater than the thickness of a decal and a restrictor device 28 is arranged in front of the face 26.

In the embodiment illustrated the restrictor comprises a bar 30 arranged transversely of the table and having adjustable mounting means 32 at each side thereof arranged to support the bar 30 on the framework 10. The adjusting means 32 permit the bar 30 to be positioned above the top surface of the table 16 at a height which is greater than the thickness of one decal but less than the thickness of two. Thus the restrictor will permit only one decal to pass below the bar 30 on top of the table 16.

A take-off means, as illustrated in Figure 4, operates in conjunction with the apparatus illustrated in Figures 1 to 3 and is arranged ta be movable from a first position over the table 16 when the table occupies an extreme position of movement to the right of the bars 12 to another position spaced from said first position. The take-off means has a flat bottom surface 40 provided with a plurality of perforations 42 (only some of which are illustrated) and means are provided to connect said perforations to a vacuum. An arrangement which is of a relatively standard construction and consequently will not be described in detail here supports the take off means and is capable of oscillating movement from a position above the table to a position above a support device for holding ware to be decorated.

Advantageously two take-off means are provided at each end of an arm whereby as one is picking up a decal the other may be depositing the design layer thereof on the ware.

In operation a stack of decals is loaded into the magazine and the piston and cylinder device is actuated to move the table 16 from the position shown in Figure 1 to the position shown at the other, right hand end of the bars 12. During this movement the valve means on the connection to the interior of the table 16 is in a position which connects said interior to a vacuum. Consequently as the table moves to the right the lowermost decal of the stack in the magazine is attracted thereto and moves towards the right with the table, the restrictor 28 ensuring that if the next decal from the stack is pulled away from the stack with the lowermost decal it is prevented from moving past the restrictor by its bar 30.Thus only one decal moves on the table 16 towards the right hand end of the apparatus and at the right hand limit of movement of the table the take-off means illustrated in Figure 4 swings over the table and has a vacuum applied to the perforations therein. When the table 16 reaches the said limit of its travel the valve means in the connection to the interior of the table cuts off the connection to the vacuum and replaces it with a connection to the compressed air source. This assists in the repulsion of the decal from the upper surface of the table on to the lower surface of the take-off means where it is held by the vacuum applied to the holes 42. The take-off means can then transfer the precisely posi tioned decal thereon to a further component of the automatic decorating apparatus.

When the decal has been removed from the upper surface of the table the piston and cylinder device 18 reverses and causes the table 16to move towards its left hand limit of movement. During this time compressed air continues to be supplied to the interior of the table thus as it passes under the stack of decals in the magazine they are forced away from the table but the lowermost decal of the pile tends to move to the left with the table and this movement continues until it abuts the fixed rear face 22 of the magazine, rearwards movement ofthe table 16 continuing after this instance.Thus the lowermost decal is precisely positioned by the rearface 22 and by the side faces 24 of the magazine so that when the table begins its movement to the right the lower most decal of the stack is positioned thereon in precisely the same position as the lowermost decal which had been previously transferred.

Various modifications can be made without de parting from the scope of the invention. For example alternative restrictor means may be employed. It has been found that a preferable form of restrictor means comprises a bar rigidly mounted to the framework, spanning the side members thereof and supporting at its centre a single threaded rod which is adjustable such that its lower end can be precisely positioned relative to the upper surface of the table.

Alternative means can be employed for causing the reciprocation of the table, and the table can be provided with alternative object attraction and repulsion means: depending on the objects to be transferred these may be electromagnetic or electrostatic. It will be realised further that various forms of take-off means other then that described with reference to Figure 4 may be provided. Positioning of the decal on thetable may assisted by forming shoulders on the upper surface of the table. In a further modification the reciprocating table could be replaced by a turntable.

The apparatus can be adapted such that different magazines 20 for accommodating decals of different sizes, for example, widths may be employed. In such a modification laterally adjustable clamp means for the magazine may be supported on the framework above the table.

If the take-off means in itself is not adjustable relative to the table it is important to provide for modification of the apparatus so that at the end of the movement of the table from left to right the centre of the decal thereon is precisely aligned with the centre of the take-off means which, in turn, is precisely aligned with the centre of the ware to be decorated. As a result stop means are provided at the right hand end of the framework to limit the rightwards travel of the table such that at the end of this travel the centre of the decal thereon is aligned with the centre of the take-off means.

When the decal is of the heat release type the take-off means may incorporate heating means so that as the decal is transferred from the table to the ware its intermediate layer is softened whereby when the take-off means presses the decal thereon on the ware the design layer adheres to the ware and the substrate is carried off on the take-off means, to be released therefrom before the take-off means is repositioned above the table. Release of the substrate may be assisted by supplying compressed air to the perforations of the take-off means at the appropriate time.

Claims (16)

1. Apparatus for transferring sheet-like objects, including a magazine with guide means adapted to receive and support a stack of shee-like objects, a transfer table at one end of said magazine, means for moving said table laterally of the magazine, object attraction and repulsion means incorporated in the table and take-off means for removing objects from the table.

2. Apparatus as claimed in claim 1 in which the magazine is arranged above the tale such that the stack therein is fed towards the table by gravity.

3. Apparatus as claimed in claim 1 or claim 2, in which the means for moving the table includes a reciprocable piston and cylinder device.

4. Apparatus as claimed in claim 1,2 or 3, in which the object attraction and repulsion means incorporated in the table comprises a plurality of perforations selectively connectable to a source of under atmospheric pressure air and a source of above atmospheric pressure air.

5. Apparatus as claimed in any one of the preceding claims, in which the table is so dimensioned that it covers the end of the magazine irrespective of its position relative thereto.

6. Apparatus as claimed in any one of the preceding claims in which the guide means of the magazine comprise stop means for limiting the movement of the bottom sheet-like object of the track in a direction opposite to that from which it is removed from the stack by the transfer table.

7. Apparatus as claimed in claim 6 in which a restrictor positioned above the top surface of the table at such a distance that it permits only one object to pass thereunder at a time is located at the side of the magazine opposite from said guide means.

8. Apparatus as claimed in claim 7 in which the restrictor is a threaded member supported by mounting means above the table for movement towards or away from the table.

9. Apparatus as claimed in any one of the preceding claims, in which the take-off means comprises a pad movable relative to the table and provided with object attraction means.

10. Apparatus as claimed in claim 9 in which the object attraction means of the take-off means is a series of perforations selectively connectable to a source of under atmospheric pressure air.

11. Apparatus as claimed in any one of the preceding claims in which means is provided for limiting the extent of movement of the table whereby the centre of the object to be transferred is aligned with the centre of the take-off means.

12. Apparatus as claimed in any one of the preceding claims in which means for supporting the magazine are adjustable for accommodating objects of different dimensions.

13. Apparatus as claimed in any one of the preceding claims in which the take-off means is mounted on a pivotable arm.

14. Apparatus as claimed in claim 13, in which an additional take-off means is supported at the other end of said arm such that one object may be deposited by one take-off means while the other is picking up another object.

15. Apparatus for transferring sheet-like objects substantially as hereinbefore described with reference to the accompanying drawings.

16. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.