GB2234488A

GB2234488A - Sheet lifting device

Info

Publication number: GB2234488A
Application number: GB9009496A
Authority: GB
Inventors: Manfred Schneider
Original assignee: RINO WERKE MASCHINENBAU GmbH
Current assignee: RINO WERKE MASCHINENBAU GmbH
Priority date: 1989-08-01
Filing date: 1990-04-27
Publication date: 1991-02-06
Also published as: GB9009496D0; DE3925393A1

Abstract

A device (1) for lifting a stacked shoot of paper (3), e.g. to be inserted into the mould of a concrete slab production machine, by means of two or more suction nozzles (13, 13', 14, 14') mounted on a carrying arm (11). The suction nozzles (13, 13') of the one side are rigidly mounted on the carrier arm (11) and the suction nozzles (14, 14') of the other side are connected to the carrying arm so as to be displaceable towards them. Furthermore, driver elements (19, 20) are associated with the displaceable suction nozzles (14, 14'); these may be rollers of rubber or plastics, which together with the effect of a hinge (18) cause the sheet (3) to rise slightly in the middle, breaking suction between sheet (3) and the one below it, so that only one sheet is delivered. <IMAGE>

Description

4 SHEET LIFTING DEVICE

DESCRIPTION

The invention relates to a device for lifting sheets of flexible material individually from a stack thereof. The device is particularly suited for use in inserting sheets of paper into the mould of a machine for the manufacture of paving or exposed aggregate concrete slabs, kerb stones or the like.

In the manufacture of concrete stone products, such as paving slabs, exposed aggregate concrete slabs, kerb stones and the like# according to the type of article to be manufactured and to the type of production machine, so-called delaying papers or filter-papers are used. These usually correspond to the outer measurement of the concrete workpiece to be manufactured, and are lifted individually from a stack of paper sheets with a device of the kind mentioned above and are deposited in the mould of the production machine. These insertion devices operate with vaccuum suction nozzles for i - 2 lifting and holding the sheets of paper,, which are reversed on couter-air above the mould box for the quickest possible discharge.

The suction of exposed aggregate concrete delaying paper can in this case be effected with almost no problems, since one side of the sheet of paper is coated with paraffin or silicon so its air permeability is thereby reduced. Filter paper, however, is intentionally very porous, so suction with known devices can be consequently problematic. often, two or even more sheets of paper are lifted which results in interruptions in production or wasted production time.

It is an object of the invention to provide an improved device of the kind mentioned which will ensure that only one sheet is lifted at a time, so that faulty operation is substantially avoided. It is' also an object of the invention to keep structural investment as low as possible. but at the same time ensure a high level of operational safety over a long period.

According to the invention there is provided a device which has suction means on one side thereof which are mounted rigidly on a carrying arm, and suction means on the other side which are connected to the carrying arm so as to be displaceable in the direction of the rigidly mounted suction means one or more driver elements which act on the sheet of material to be lifted being associated with the adjustable suction means.

Preferably, the displaceable suction means are nozzles and the driver elements associated therewith are mounted together on a plate, which is connected to the carrying arm via a hinge or is displaceable in the direction of the rigidly mounted suction means which are also nozzles by means of a servo-mechanism, e.g. in the form of a cylinder, which is provided with a piston acting on the plate and which is supported on the carrying arm.

In one embodiment, the elements are pulleys mounted rigidly on the plate and consist of rubber, plastics or another material with a high friction coefficient.

- 4 It is further proposed to hold the rigidly mounted suction nozzles in a plate which is connected in a fixed manner to the carrying frame via an intermediate member.

If a device is formed according to the invention for use with a stack of filter papers in which the suction nozzles of one side are rigid and the suction nozzles of the other side are displaceable, and the latter are associated with driver elements, it is ensured that even in the processing of the filter papers, the device lifts only one sheet at a time. When the suction nozzles are rested on the paper stack, by the contact pressure or by means of a servo-mechanism, the dis placeably held suction nozzles of one side are moved towards the rigidly mounted suction nozzles, so that the uppermost sheet of the paper stack is slightly pushed-inwards on one side and is thus bowed upwards. As a result, an air cushion is formed under the paper or the edges of the suction nozzles of one or both sides are lifted up in the regions thereof which face each other, and the sheet underneath is therefore not lifted up as well when the device is raised. This arrangement ensures that only one sheet of paper is -!3 gripped at a time by the device and inserted into the mould of the production machine. operational faults are thereby reliably avoided -and, since only a few components are needed to permit this, only minimal manufacturing and investment costs are necessary to improve the function of such devices. Furthermore, existing apparatus can be updated without problems. The device according to the invention therefore operates extremely reliably with a high level of operational safety.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:Figure 1 is a side view of a device of the invention before lifting a sheet of paper, Figure 2 shows the device of Figure 1 during lifting of a sheet of paper and; Figure 3 is a plan view of the device of Figure 1.

1 The device 1 shown in Figures 1-3 is for lifting a sheet of paper 3 from a stack of paper 2, in order to insert the sheet of paper 3 into the mould of a production machine for making concrete products (not shown). To this end, preferably reversible suction nozzles 13, 131 and 14, 141, by means of which the sheet of paper 3 is held under suction during transport of the device 1,, are mounted in a row,- in each case, on a carrying arm 11, whose height is adjustable by means of a ram 12.

In order that only one sheet is lifted from the stack 2 of paper at a time. even when air-permable filter paper is being processed the suction nozzles 13 and 131 are mounted rigidly on the carrying frame 11 and the suction nozzles 14, 141 are held displaceably, on the other hand, in the direction of the suction nozzles 13.13'. To this end a hinge 18 is provided, via which a plate 16, into which the suction nozzles 14, 141 are inserted, it pivotably connected to the carrying arm 11. Furthermore,, two driver elements 19 and 20 are rigidly mounted on the plate 16 in the form of pulleys made of plastics, rubber, or another material with a high friction coefficient. The rigid mounting of the 4 suction nozzles 13 and 13' is effected by means of a plate 15, into which they are inserted and which is connected in a fixed manner to the carrying frame 11 via an intermediate member 18.

if a force is exerted via the carrying frame 11 on the suction nozzles 14, 1C, which like the suction nozzles 13, 131 are connected to a compressed air source (not shown) and by means of which the sheet of paper 3 is lifted by suction, the suction nozzles 14, 141 are pushed slightly towards the centre of the stack of paper 2, as shown in Figure 2. The rigidly mounted suction nozzles 13, 131 thus form an abutment, so that the sheet of paper 3 is more or less arched. Thus an air cushion is formed under the sheet of paper 3 and the ecges of the suction nozzles 13, 131 14, 141 are slightly lifted in the region facing the arch, the suction effected penetrating the sheet of paper 3 is thereby interrupted and the sheets of paper lying underneath remain on the stack of paper 2. In each working process, the device 1 therefore only lifts the uppermost sheet of paper in each case from the stack of paper 2.

- -8 - 1

Claims

1. A device for lifting a stacked flexible sheet comprising suction means for holding the sheet which are mounted opposite one another on a carrying arm and are connected to a low pressure source, the suction means on one side of the device being rigidly mounted on the carrying arm and the suction means on the other side being connected to the carrying arm so as to be displaceable in the direction of the rigidly mounted suction means, and one or more driver elements associated with the displaceable suction means and operable to act on the sheet to be lifted.

2.. A device according to claim 1, wherein the displaceable suction means are nozzles and the driver elements associated therewith are mounted together on a plate which is connected to the carrying arm via a hinge or is displaceable in the direction of the rigidly mounted suction means by a servo-mechanism, e.g. in the form of a cylinder supported on the carrying arm with a piston acting on the plate.

4 - 9

3. A device according to claim 1 or 2,, wherein the driver elements are rigidly mounted on the plate and consist of pulleys made of rubber. plastics or another material with a high friction coefficient.

4. A device according to any one of claims 1 to 3, wherein the rigidly mounted suction means are held in a plate which is connected in a fixed manner to the carrying frame via an intermediate er.

5. A device for lifting a stacked sheet of paper substantially as herein described with reference to the accompanying drawings.