GB2071623A

GB2071623A - Loosening and separating sheets from pile

Info

Publication number: GB2071623A
Application number: GB8104817A
Authority: GB
Original assignee: Compagnie Industrielle Radioelectrique SA
Current assignee: Compagnie Industrielle Radioelectrique SA
Priority date: 1980-02-22
Filing date: 1981-02-16
Publication date: 1981-09-23
Also published as: DE3105607A1; FR2476616B1; FR2476616A1; IT8120853V0; IT8119891A0; CH634011A5; GB2071623B; IT1135565B; ES8205703A1; ES499648A0; JPS56155130A

Abstract

Upper sheets of paper are fed to a linear conveyor entrainment arrangement (14-18) by a rotating suction drum (12, 13) from a magazine (2) having a rising base (5) lifting the pile of sheets (1). A vertical strip (4) for retaining lower sheets is arranged alongside the stack and has an upper curved knife-edge (4a). Just below the knife-edge (4a) the strip has a compressed air orifice supplied by pipe 45. This jet loosens and separates the upper sheets making them easier to pick up by the suction drum. The base (5) rises as counterweight (10) descends into liquid (41). <IMAGE>

Description

SPECIFICATION Installation for the introduction of stacked sheets of paper one by one into an entrainment device The present invention relates to an installation for introducing stacked sheets of paper one by one into a linear entrainment device, the installation being of the type which comprises a magazine to receive a stack of sheets the magazine having a base which rises progressively as the sheets depart, a device for removing sheets from stack, said device comprising constituted by a perforated drum which rotates about a suction chamber at a circumferential speed substantially equal to the speed of the linear entrainment device, and suction chamber being connected to a source of reduced pressure through a valve opened intermittently at the introduction rate of the sheets to the entrainment device.

An installation of this type is known from German Patent Application 26 00 773. In this installation, relatively sophisticated means are provided for controlling the electromagnetic valve of the suction chamber such that there is always a certain distance between the sheets introduced in succession into the linear entrainment device.

However it happens that incidents may occur owing to certain sheets sticking to each other, which are thus entrained simultaneously by the perforated drum.

The present invention intends to obviate or at least mitigate this drawback.

According to the invention an installation of the aforesaid type further comprises a separator for the sheets comprising a rounded knife-edge located approximately one to two centimetres after the suction region of the perforated drum, and said separator being provided with a blower orifice sending a jet of air about a horizontal axis in the direction of and at the height of the upper sheets in the stack.

The separator makes it possible to ensure the separation of even very thin sheets of paper in a reliable manner. Furthermore, it is thus possible to achieve relatively high introduction speeds.

In order to make it possible to achieve such speeds, the suction chamber preferably comprises a fixed hollow shaft supporting the rotary perforated drum.

The apparatus according to the invention is particularly intended for the introduction of new bank notes into a checking device, but it can be used for conveying any printed or unprinted sheets of paper.

The accompanying drawings illustrate one embodiment of the invention by way of example.

Fig. 1 is a view of an installation formed according to the invention, in elevation and partial section; Fig. 2 shows the separator as seen along arrow A; Fig. 3 is a view of the separator in detail and partial section; and Fig. 4 is a sectional view on line IV--IV of Fig. 1 of the device for removing sheets from the stack.

Sheets 1 to be engaged are stacked in a vertical magazine 2 of which a rear wall 3, a front wall 4 which also acts as a separator, as well as a base 5 have been shown. This base 5 is integral with a support 8 mounted to slide vertically on an upright 9 and connected to a metal counterweight 10 by a cord passing over a pulley 40. The counterweight is slightly heavier than the base 5 laden with a complete stack of sheets. When the stack is thick it is also relatively compressible so that pressure may be exerted by the counterweight. In order to take into account the reduction in weight of the stack of sheets due to the removal of sheets, the counterweight may advantageously be immersed progressively, as it descends, in a liquid 41, the Archimede's thrust progressively reducing the traction force on the base 5.

Engagement and introduction apparatus 11 is constituted essentially by a perforated drum 12 set in rotation in the direction of arrow F1 about a fixed suction head 1 3 constituting the end of a hollow shaft 25 (Fig. 4). The engagement and introduction apparatus 11 imparts an acceleration to the sheet in order to propel the latter into a linear entrainment device 14, at the same speed as this linear entrainment device. Under the circumstances, the latter is constituted by an endless belt 15 moving in a linear manner on free rollers such as 1 6 and 1 7 projecting slightly beyond the surface of the table 18.

The head 13 is connected via the hollow shaft 25 to a spurce of vacuum by way of an electromagnetic valve 19 controlled by a pulse generator 20 producing a square wave amplified by an amplifier21.The intermittent interruption of the suction makes it possible to ensure engagement of the sheets one after the other with a predetermined space therebetween. The pulse generator 20, of adjustable frequency, makes it possible to ensure an optimum introduction rate.

The suction time can also be adjusted easily by the width of the square pulses. It is also possible to synchronize the generator 20 and the entrainment device 14.

In order to prevent two sheets from being entrained simultaneously, by sticking together, a separator is provided, constituted by the upper end 4a of the wall 4, in the form of a rounded knife-edge (Fig. 2), located approximately one to two centimetres (for example approximately 15 mm) to the right of the suction aperture and approximately 1 mm from the perforated drum.

The rounded edge takes into account a certain curvature of the sheets. This knife-edge 4 also comprises a blower orifice 42 connected by a channel 43 and a connection 44 to a pipe 45 connected to a source of compressed air. The jet of air, directed substantially about a horizontal axis in the direction of the sheets 1, separates the ends of the sheets located below the device 11 one from the other.

Located at the inlet of the entrainment device 14 are a flat connecting surface 23 and an inclined deflector 24 retaining the front edge of the sheet in the case where the latter would have a tendency to bend.

The engagement and introduction apparatus 11 is shown in detail and in section in Fig. 4. The suction head 13 is formed at the end of the stationary hollow shaft 25 fixed to a frame 26 by means of a nut 27. The perforated drum 12 is made in one piece with a tubular shaft 28 rotating about the stationary shaft 25 through the intermediary of needle bearings 29 and 30. The tubular shaft is driven by a belt 39 or by a pinion.

The left-hand end of the tubular shaft 28 is closed off by an annular member 31 rotating on the end 32 of the shaft 25 through the intermediary of ball bearings 33.

The suction head 13 comprises a cavity 34 connected to the interior 35 of the stationary shaft 25 and opening out in a longitudinal slot 36 on the lower cylindrical side of the head 13, as visible in Fig. 1. For machining reasons, the cavity 34 is closed off at the top by a plate 37 of synthetic material. The other end of the hollow shaft 25 is connected to a connecting member 38 for connecting it to the electromagnetic valve 19. In the example in question, the wall drum 12 is in the form of a very thin screen having a thickness less than 0.5 mm (for example a thickness of 0.3 mm) comprising at least 200 holes per cm2 (for example 323 holes of a diameter of 0.4 mm per cm2). This screen rotates about the suction head 13 at a distance of 0.02 mm from the latter. The apparatus is connected via the electromagnetic valve 19, to a vacuum pump having an output of 40 m3/hour.The noise produced by the suction through the screen is an ultra-sound noise inaudible to the human ear. The strong air current through the holes of the screen is sufficient to entrain the sheet located at a distance of several millimetres and to press the latter against the screen constituting the drum 12. The tubular shaft 28 is driven continuously either by a belt or by a pinion.

The dimensions given above have naturally been given solely by way of example. These dimensions being able to vary to a certain extent without the result obtained being jeopardized.

The engagement and introduction apparatus may also have numerous variations. For example, the stationary shaft could be fixed by its two ends in a frame and the perforated cylindrical drum could be constituted by a thicker part driven directly by one or two belts and mounted by its ends on two ball bearings. In order to increase the suction effect, slightly countersunk holes may be provided on the perforated surface.

Claims

1. An installation for the introduction of stacked sheets of paper one by one into a linear entrainment device, said installation comprising a magazine to receive a stack of sheets, the magazine having a base which base rises progressively as the sheets depart, a device for removing sheets from the stack, said device comprising a perforated drum which rotates about a suction chamber at a circumferential speed substantially equal to the speed of the linear entrainment device, said suction chamber being connected to a source of reduced pressure via a valve opened intermittently at the introduction rate of the sheets to the entrainment device, a separator for the sheets comprising a rounded knife-edge located at approximately one to two centimetres after the suction region of the perforated drum, and said separator being provided with a blower orifice sending a jet of air about a horizontal axis, in the direction of and at the height of the upper sheets in the stack.

2. An installation as claimed in claim 1, in which the suction chamber comprises a stationary hollow shaft supporting the rotary perforated drum.

3. An installation as claimed in claim 2, in which the perforated drum has a wall thickness less than 0.5 mm, in said wall there are at least 200 holes per cm2, and the distance between the perforated drum and the hollow shaft is less than 0.05 mm.

4. An installation for the introduction of stacked sheets of paper one by one into a linear entrainment device, substantially as hereinbefore described with reference to the accompanying drawings.