US3378131A

US3378131A - Drying devices

Info

Publication number: US3378131A
Application number: US613358A
Authority: US
Inventors: Weber Erich
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-02-04
Filing date: 1967-02-01
Publication date: 1968-04-16
Anticipated expiration: 1985-04-16
Also published as: DE1629137C3; GB1115148A; FR1599673A; DE1629137A1; NL6701737A; AT296349B; DE1629137B2; BE693703A; CH458402A

Description

April 16, 1968 E. WEBER 3,378,131

DRYING DEVICES Filed Feb. 1, 1967 r 5 Sheets-Sheet 1 Fig.1

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E I 4' 0 1L We 5 k April 16, 1968 E. WEBER 3,378,131

DRY ING DEVICES April 16, 1968 E. WEBER 3,378,131

DRYING DEVICES Filed Feb. 1, 1967 5 sheetsrsheet Inventor: EFLCZL W'eber vffi w 5 1 44 2 fi Arm,

United States Patent 0 "ice 3,378,131 DRYING DEVICES Erich Weber, Biutenstrasse It), 13 Munich, Germany Filed Feb. 1, 1967, Ser. No. 613,358 Claims priority, application (olzrmany, Feb. 4, 1966,

W 4 7 Claims. (Cl. 198-434) ABSTRACT OF THE DISCLOSURE The invention relates to devices for drying fiat printed sheets such as sheets of paper, cardboard, synthetic resin, millboard, sheet metal, or wood. When sheets of such materials are still wet after leaving the printing machine, for example, a screen printing machine, it is a known practice to lay the sheets with their printed side upwards on a conveyor belt and only to invert the sheets or stack them when the printing ink or lacquer is completely dry, such a drying process requiring a considerable time and therefore requiring the use of a long conveyor belt.

Drying devices in the form of horizontally running conveyor belts have the disadvantage of requiring a large amount of floor space and vertically travelling ones have been proposed in order to reduce the amount of floor space needed, though their height is of course limited by the height of the building in which they are used. One such previously proposed drying device in the form of a vertically running conveyor uses endless sprocket chains running over upper and lower sprocket wheels and provided with carriers for the printed sheets. The conveyor chains first move the sheet carriers upwards, then turn them over and move them down again. A disadvantage is that the turning over causes the sheets to rest on their printed surfaces on the descending carriers so that if smearing is to be avoided the sheets must be dry before they are turned over and the descending limb of the conveyor with its carriers does not serve for drying. Although attempts have been made to avoid the turning over of the sheets at the top end of the conveyor, such conveyors are complicated in construction, expensive and not entirely reliable in use.

One object of the present invention is to provide a sheet drying device having at least one chain conveyor which has ascending and descending limbs with carriers for sheets to be dried, in which the transfer of sheets from the top of the ascending group of carriers to the top of the descending group of carriers is achieved in a simple manner without the sheets being inverted. A further object of the invention is to provide a sheet drying device which takes up little space and has a large drying capacity.

Yet a further object of the invention is to provide drying devices which can be easily connected together in tandem so that sheets are automatically transferred from one drying device to the following one for further drying.

A still further object of the invention is to provide a drying device or drying installation which is suitable for use with automatically operating printing machnery.

The present invention consists in a device for drying printed sheets, comprising a link-type sprocket conveyor chain having ascending and descending limbs, chain guide 3,378,131 Patented Apr. 16, 1968 means at the top and bottom of the limbs, a frame carrying the guide means, means for driving the chain conveyor, sheet carriers attached to links of the sprocket chain 50 as to project at an agle from the limbs of the chain, means for laying sheets on the carriers near the bottom of the chain, means for removing sheets from the carriers of the descending limb of the conveyor chain, the carriers sloping in such a manner that adjacent to the top of the conveyor chain sheets tend to slide obliquely downwards from a carrier in a delivery position near the top of the ascending chain limb across on to a carrier in a receiving position near the top of the descending chain limb, the carriers in. the receiving and delivery positions being approximately coplanar, the drying device further comprising a transfer conveyor for promoting movement of sheets from a carrier in the delivery position to a carrier in the receiving position, and means for causing the spacings between, on the one hand, a carrier in the delivery position and a carriage higher up, and, on the other hand, a carrier in the receiving position and a carrier higher up, to be wider than the spacings between carriers in the ascending and descending limbs of the conveyor chain, the wider spacings providing gaps through which sheets can pass on the transfer conveyor from a carrier in the delivery POSltlOl'l to a carrier in the receiving position.

It will be seen that with a machine or device as defined in the last preceding paragraph there is no inversion of the sheets on transfer from the top of the ascending conveyor limb to the top of the descending one, so that drying need not be completed in the ascending limb.

The limbs of the conveyor chain can conveniently be inclined to the vertical.

In accordance with a further feature of the invention, the drying device can comprise two horizontally spaced sprocket wheels at the top of the conveyor chain limbs for causing the conveyor chain to extend in a straight line between these sprockets.

The transfer conveyor can be in the form of a conveyor belt.

In a preferred embodiment of the invention the drying device comprises two such sprocket chains, approximately horizontal bars extending between the chains and forming parts of the carriers, and spacer parts which carry the bars on the conveyor chain links, the spacer parts holding the bars some distance from the links. The device can be so designed that the spacer parts are replaceable by spacer parts of a different size.

In accordance with a further feature of the invention, a part of the descending limb of the conveyor chain extending from the sheet removing means to the bottom of ihe sprocket chain is set at an angle to the ascending chain irnb.

The invention also consists in an installation comprising two or more drying devices in accordance with the invention, both inclined at the same angle to the vertical, means being provided for transferring sheets from the descending chain limb of one device to the ascending conveyor chain limb of the other device.

The invention is now described with reference to the attached drawings.

FIG. 1 shows a drying device in accordance with the invention from the side.

FIG. 2 shows two drying devices of the construction shown in FIG. 1 arranged to form an installation in which sheets are dried first on one drier and then on the second one.

FIG. 3 is a partial section, on a large scale, of the top part of the drying device shown in FIG. 1.

As shown more particularly in FIGS. 1 and 3, the dry ing device comprises a sprocket chain conveyor frame 1 which is inclined to the vertical and is mounted on a base 2 with which it is additionally connected by a stay or frame 3. On each side of the frame 1, I provide a linktype sprocket conveyor chain 4, and each of the two such chains runs at its top end over two horizontally spaced sprocket wheels so that the top part of each conveyor chain extends in an approximately straight line between the sprocket wheels 5. At the bottom of the drying device the conveyor chains pass over further sprocket wheels which are not specially shown in the drawings. The sprocket wheels constitute chain guide means.

Each sprocket chain comprises an ascending limb running on the left-hand side of the frame 1 in the upward direction A, while on the other, right-hand side it forms a descending limb running in the downward direction R. The links of the chain have sheet carriers 6 fixed to them for carrying printed sheets 7 to be dried. In order to mount the carriers 6 on the chain links, the chain link halves 8 have bent-over portions 9 perpendicular to the planes of the sprocket chains and carrying spacer parts 10 with bolts 11 which fix horizontal bars 13 in the form of tubes with flattened ends to the spacer parts 10. Each bar 13 is connected at its ends to the spacer 10 on the two conveyor chains. Reference numeral 14 indicates nuts on bolts 11, the latter extending through the spacer parts 10. The bars 13, which form parts of the carriers 6, are therefore arranged like the rungs of a ladder having the same pitch or spacing on the ascending limb of the conveyor chains as the links of the chain, though, if required,

carriers

6, 13 could be arranged on only every other or every third conveyor chain link instead of on every one.

The carriers 6 can for example be in the form of round metal rod or wire welded or otherwise fixed to the bars 13. Each bar 13 carries several such rods, for example 6, arranged at equal distances along the length of the bar in the manner of prongs. The ends of the rods remote from the bars 13 are not connected together.

Owing to the use of the spacer parts 10, which can. be replaced by others of different lengths, the centre to centre spacing of the bars 13 is greater than the chain link pitch in those parts where the chain is curved. In the straight part of the conveyor chain between the sprocket wheels 5, there is a spacing s between bars 13 in accordance with the link pitch of the chain and the diameter of the bars 13. At the top of the ascending limb of the conveyor chain Where a carrier 6 moves from the sheet delivery position (6, to be described below) to the position in which it is approximately vertical (see FIG. 1), there is a considerable widening of the bar spacing to a value S. Similarly there is a wider spacing between the bar of the carrier in the receiving position marked 6 and the preceding higher up carrier. The provision of these wider spacings S enables a printed sheet 7 to slide off the carrier in the delivery position 6', as indicated by arrow T, on to the carrier in the receiving position 6" at the top of the descending limb of the conveyor chain, without there being any danger of the top surface, which carries the wet printed image, being smeared or streaked by bars 13 at the very top of the drying device. The carriers in the delivery position 6' and the receiving position 6" are approximately coplanar. In order to make the frame 1 more rigid, it is provided with at least one transverse strut 15 (see FIG. 3) on which an angle piece 16 is welded, the latter having bolts 17 carrying a plate 18. The two flat pieces or plates 18, one being provided on each side of the device, carry bearings for the shafts 19 of rollers 20 which carry a belt 21 forming a transfer conveyor, moving in the direction of the arrow. The transfer conveyor promotes the movement of a sheet 7 in the oblique downward direction T from a carrier 6' to 'a carrier in the receiving position 6".

In order to prevent the inclined sheets 7, which are moving upwards in the direction A and downwards in the direction R, from sliding oil? the carriers 6, abutments 22 (see FIGS 1 and 2) are provided for the descending sheets, while similar abutments, not specially shown, are

provided for the ascending sheets. The abutments 22 are held in place by a bracket 23.

At the top of the conveyor chains, however, the abutments for preventing the ascending sheets 7 from sliding downwards to the right off the carriers 6 are discontinued, so that a sheet can slide from the carrier in the delivery position 6' in the direction of the arrow T on to the carrier in the receiving position 6" until it is halted by the abutments 22. This sliding movement of the sheet is initiated by the slope of the carrier in the delivery position 6. The sheet then crosses the gap between the carrier in the delivery position and transfer conveyor which transports on to the carrier in the receiving position 6" on which the sheet slides until it comes to rest against the abutments 22.

In operation, printed sheets are delivered in the direction of the arrow E (see FIG. 1) and are deposited on the series of bars 24 extending between the rods of the carriers 6. The bars 24 are fixed in position and are carried by brackets 25. The rods of a carrier 6 moving upwards then pass between the bars 24 and lift the printed sheet resting on them upwards in the direction A, the sheet being prevented from sliding off the carrier by the abutments (not shown) previously referred to. At the top of these abutments, the sheet can then slide downwards to the right from the carrier in the delivery position 6' on to the transfer conveyor which promotes its sliding movement on to the carrier in the receiving position 6". From this position the printed sheet to be dried is moved downwards in the direction R and is taken up by a sheet removing means in the form of a conveyor belt 26 acting in the direction P.

The conveyor chains 4 are driven by drive means in the form of an electric motor 27 which is switched on and off automatically so as to operate the chains 4, with which it is connected by chain 28, in steps. A further electric motor 29 drives the transfer conveyor by means of a belt or the like 30. An electric motor 31 is provided for driving the sheet removing belt 26, via a transmission 32.

At the position at which the sheets 7 are removed from the carriers 6, the latter are caused to fan out to make a larger gap owing to the fact that the part of the descending limb of the conveyor chains extending from the position at which sheets are removed by belt 26 to the bottom of the conveyors makes an angle with ascending limbs of the conveyor chains, as is indicated by reference numeral 4'. This facilitates the operation of the belt 26.

In the installation shown in FIG. 2, two substantially similar drying devices of the construction shown in FIG. 1, are arranged in tandem and both are inclined at the same angle to the vertical. Means including the belt 26 serve to transfer the sheets 7 from the descending limb of the conveyor chain of the left-hand drying device in the direction of the arrow P on to the receiving bars 24 of the second drying device of the installation, so that the sheets are manipulated by the second drying device in exactly the same manner as by the first device. The sheet removing means (belt 26) of the second, right-hand, drying device deposits on a suitable stand or the like. Owing to the inclination of the two devices to the vertical, the installation shown in FIG. 2 requires less floor space than two separate drying devices. The devices can be arranged so that they can be easily disconnected for use separately. If required more than two drying devices can be connected together in a train for drying sheets.

Various modifications can be made in the device described within the scope of the following claims.

What I claim is:

1. A device for drying printed sheets, comprisingat least one link-type sprocket conveyor chain having ascending and descending limbs, chain guide means at the top and bottom of the limbs, a'frame carrying the guide means, means for driving the chain conveyor, sheet carriers attached to links of the sprocket chain so as to project at an angle from the limbs of the chain, means for laying sheets on the carriers near the bottom of the chain, means for removing sheets from the carriers of the descending limb of the conveyor chain, the carriers sloping in such a manner that adjacent to the top of the conveyor chain sheets tend to slide downwards from a carrier in a delivery position near the top of the ascending chain limb across on to a carrier in a receiving position near the top of the descending chain limb, the carriers in the receiving and delivery positions being approximately coplanar, the drying device further comprising a transfer conveyor positioned adjacent to top of the ascending and descending chain limbs for promoting movement of sheets from a carrier in the delivery position to a carrier in the receiving position, and means for causing the spacings between, on the one hand, a carrier in the delivery position and a carrier higher up, and, on the other hand, a carrier in the receiving position and a carrier higher up, to be wider than the spacings between carriers in the ascending and descending limbs of the conveyor chain, the wider spacings providing gaps through which sheets can pass on the transfer conveyor from a carrier in the delivery position to a carrier in the receiving position.

2. A device according to claim 1 in which the limbs of the conveyor chain are inclined to the vertical.

3. A device according to claim 1 further comprising two horizontally spaced sprocket wheels at the top of the conveyor chain limbs for causing the conveyor chain to extend between them in a straight line.

4. A device according to claim 1 in which the transfer conveyor is a conveyor belt.

5. A device according to claim 1 comprising two such sprocket chains, approximately horizontal bars extending between the sprocket chains and forming parts of the carriers, and spacer parts which carry the bars on the conveyor links, the spacer parts holding the bars some distance from the links.

6. A device according to claim 5 in which the spacer parts are replaceable by spacer parts of different sizes.

7. A device according to claim 1 in which a part of the descending limb of the sprocket conveyor chain extending from the sheet removing means to the bottom of the sprocket conveyor chain is set at an angle to the ascending limb of the sprocket chain.

References Cited UNITED STATES PATENTS 370,969 10/1887 Rheutan 198-134 1,853,478 4/1932 Vincent 198-134 RICHARD E. AEGERTER, Primary Examiner.