Abstract: A conveyor and methods for turning cases. The conveyor includes a pair of side-by-side belts running preferably at different speeds. The different belt speeds cause the leading edge of a package straddling both belts to move toward the slower belt. The two belts include transverse rollers that can be selectively actuated in a series of actuation zones along the conveyor to push packages conveyed atop them to the right or to the left. A controller controls the actuation of the belt rollers in each zone sequentially so that the belt rollers supporting the leading edge of the package push it towards the slower belt and the belt rollers supporting the trailing edge of the package push it towards the faster belt to accelerate the turning of the package as the belts advance.

Abstract: In a machine for feeding a partially formed carton in a conveying direction and reorienting the carton for completion, a turn-assist mechanism and related methods help to ensure that proper turning of a skewed carton is achieved in a reliable and highly efficient manner. The mechanism comprises a bed for supporting the carton, which may be skewed from a first orientation in which one of the side flaps could be folded and sealed in an upstream procedure. A conveyor includes at least one lug with a portion generally elongated in a direction transverse to the conveying and vertical directions for engaging a trailing end of the carton. This engagement helps to turn the carton to a second, squared orientation approximately 90° rotated from the first orientation so that the forming operation may be completed, such as by folding and sealing any other side flaps.

Abstract: A conveyor and methods for turning cases. The conveyor includes a pair of side-by-side belts running preferably at different speeds. The different belt speeds cause the leading edge of a package straddling both belts to move toward the slower belt. The two belts include transverse rollers that can be selectively actuated in a series of actuation zones along the conveyor to push packages conveyed atop them to the right or to the left. A controller controls the actuation of the belt rollers in each zone sequentially so that the belt rollers supporting the leading edge of the package push it towards the slower belt and the belt rollers supporting the trailing edge of the package push it towards the faster belt to accelerate the turning of the package as the belts advance.

Abstract: A device for the turning of flat articles, particularly blanks of folded boxes, includes conveying elements which define at least two conveying sections that are permeable to air and on which the articles are conveyed lying substantially flat, the conveying elements being mounted in a frame, a suction device arranged below the conveying element and to extend through the conveying section to increase the friction between the conveying elements and the articles, and a separate drive for each of the conveying elements of the respective conveying sections. The frame is mounted such that it can swivel about a pivot in the exit region of the frame relative to a machine frame.

Abstract: To orient groups of products to be packaged in a plastic film the groups (G) are wrapped in lengths of film and fed between two series of opposite conveyor belts (211, 212). Each series of belts comprises several parallel belts controlled at proportionally variable speeds to cause the group (G) to rotate through approximately 90° about an axis orthogonal to the direction of feed.

Abstract: An non-contact article rotating device is disclosed that rotates articles without impacting or contacting the article other than the bottom of the article. The device is designed to accept a stream of articles with minimum gaps between them, and rotate only those that are programmed to be rotated. The device accepts any combination of rotated and non-rotated articles and can rotate them through angles up to and through 360 degrees. One embodiment of the disclosed device uses only one single-speed drive motor and pneumatic components to operate two conveyor roller sections. While one conveyor roller section maintains a constant speed, the conveyor rollers of the second conveyor roller section are sequentially braked and unbraked to rotate an article that is positioned partially on the first conveyor roller section and partially on the second conveyor roller section. The difference in speeds between the two conveyor sections rotates the article.

Abstract: A transport and alignment system is provided for handling stacked sheet material on a support deck including first and second belts each having a portion thereof disposed parallel to the support deck. Each of the belts includes a plurality of spaced-apart fingers which engage the edges of the stacked sheet material and define a pocket therebetween. The transport and alignment system further includes a drive mechanism for independently driving the first and second belts to effect concurrent and relative motion of the fingers. Concurrent motion of the fingers transports the stacked sheet material along the support deck while relative motion of the fingers opposed edges of the stacked sheets of material. The transport and alignment system is described in the context of a stitcher and chassis module of a mailpiece inserter.

Abstract: A virtual lug loader includes a lug loader for loading workpieces in a flow direction into the spaced apart lugs on a lugged conveyor, wherein the workpieces are transversely oriented relative to the flow direction. The lug loader includes an array of pairs of endless conveyors for conveying the workpieces downstream, wherein each pair of endless conveyors in the array include first and second endless conveyors. The first and second endless conveyors are spaced laterally apart across the flow direction. Each are aligned substantially in the flow direction. The array forms a continuous upper surface in the flow direction for supporting the workpieces translating downstream in the flow direction. Each pair of endless conveyors in the array overlap adjacent pairs of endless conveyors in the array. At least one pair of endless conveyors in the array include independently actuable first and second drives independently driving their corresponding first and second endless conveyors.

Abstract: A conveyor (20) comprising at least one belt (22) defining an outer conveying surface divided into at least two laterally offset regions in which the rollers (50) in one region rotate in a first direction and the rollers (51) in a second region rotate in a second direction as the conveyor belt (22) advances in a conveying direction. The rollers (50, 51) rotate by rolling along roller-engagement surfaces (54) underlying the conveyor belt along a carryway. The rollers rotating in the first direction rotate with a velocity component in the conveying direction (32) different from the velocity component in the conveying direction of the rollers rotating in the second direction. An article positioned simultaneously atop rollers in both regions is rotated by the rotation of the rollers as the conveyor belt advances.

Abstract: Method and device for pivoting plate elements travelling on a flat conveyor, the conveyor being provided with two parallel left and right paths, respective driven at different speeds. The paths define between them a separating line on which the plate elements are rotated around an axis by application of each of the two path speeds on a left portion of the plate element and on a right portion of the plate element defined by the separating line. The method involves maintaining the barycenter of each plate element sufficiently close to the separating line to extend the effect of the rotation applied to these plate elements.

Abstract: The method relates to products such as bottles (1) whose horizontal cross section of contact is oval and which are conveyed in the longitudinal direction, in single file and spaced apart, on a conveyor (2). This method consists in: introducing said bottles one by one into a neck, at the downstream end of which are motorized rollers (5), (7), applying said rollers to the opposite faces of each bottle to be orientated, and giving the roller (5), termed the passive roller, a peripheral speed equal to the speed of conveyance of the bottles (1) and giving the other roller (7), termed the active roller, a higher peripheral speed so as to position the bottle (1) diagonally on the conveyor (2). The invention also relates to the device for carrying out the method, comprising a neck consisting of two arms (6) and (8) forming a V, at the end of which are the motorized rollers (5) and (7).

Abstract: A device for orienting tubular preforms which are fed in bulk by a supply device, including two continuous endless conveyors which are disposed side by side and which are equipped respectively with two parallel lines which are separated horizontally from one another by a distance that is greater than the largest cross-sectional dimension of the preforms. According to the invention, the preform-supply device is disposed above one end of the two conveyors. The two conveyors are moved by drive device in opposing directions in order to pivot any preforms that arrive positioned sideways across the conveyors and to drop the longitudinally-oriented preforms into the space between the two conveyors. The orienting device also includes an endless belt for collecting preforms, which extends beneath the two conveyors parallel thereto and which is used to collect and move the horizontally-laid longitudinally-aligned preforms one after the other.

Abstract: Systems and methods for article conveyance and orientation are provided. The system includes first and second conveyors, which convey articles in a conveying direction. The system also includes first and second sensors, which detect articles conveyed on the first and second conveyors, and which are coupled to a controller. The controller, based on information received from the first and second sensors, controls the first and second conveyors to orient the articles so that the articles have a size in a direction of conveyance which is greater than a size in a direction transverse to the direction of conveyance. The controller also controls the system to prevent another article from being conveyed onto the first and second conveyors when an article is being oriented.

Abstract: A device for aligning parcel goods, in particular bottle crates, boxes, trays or the like during conveyance, and having a conveyor device with a roller conveyor belt having two-part freely rotatable rollers, whereby the conveyance takes place in a plane of conveyance and the alignment takes place in an alignment area situated at least partially in the plane of transport, with a plurality of manipulation units that can be operated in a controlled manner and are situated above and/or below the roller chains in the alignment area. The manipulation units are able to alter the speed and/or the direction of rotation of the rollers for rotation of a parcel about an axis perpendicular to the plane of transport, with at least one preferably optical recognition device which detects the aligned position of the parcel and a control device which controls the process of alignment of the parcel.

Abstract: A system and method for manipulating articles includes providing a bed having at least one conveying surface. The conveying surface is adapted to move articles in a direction of conveyance from an upstream end to a downstream end of the bed. At least one sensor is provided to determine the position of any articles on the bed. Selected articles are moved in the direction of conveyance at a speed that is generally higher than articles traveling on the bed that have yet to be manipulated and the articles are selectively rotated.

Abstract: An apparatus having approximately parallel conveyors (2, 2?) for transporting and rotating an article (G) has multiple longitudinally arranged omnidirectional rollers (24), each omnidirectional roller (24) having multiple individual rollers (240) arranged about its periphery. The conveyors (2, 2?) extend in a transporting direction (T), bear against the bottom of the article (G), and rotate the article about an axis perpendicular to the article bearing plane. At least one conveyor can be driven at a speed different from the other conveyor to transport and rotate the article on the conveyor. The bearing portion of article (G) is subject to direction-dependent coefficients of friction with the transporting direction (T) having a static or sliding coefficient of friction that is higher than the rolling coefficient of friction in the direction perpendicular (S) to the transporting direction (T).

Abstract: A device for positioning separately supplied elongate meat products, comprises two driven endless aligning conveyors running with the transport paths substantially parallel to each other, which transport paths together form a support for the meat products for transporting such that, at the position where the transport paths are mutually adjacent, they are in a lower position than when at a greater mutual distance. This structure also relates to a method for positioning separately supplied elongate meat products.

Abstract: The invention relates to a device (1) for feeding cigarette packets (3) out of a packing machine, where the packets (3), being substantially in the shape of parallelepipeds, are moved forward with their large lateral faces (4) in contact with each other along a first path (P1) by a conveyor (2) that stabilises them in a defined direction (D) transversal to the large lateral faces (4). Downstream of the stabilising conveyor (2), there is a unit (33) for printing on the packets (3).

Abstract: A conveying device (1) with change of direction for conveying stock, preferably on pallets (2) or the like, along a first conveying line (3) and along a second conveying line (4) oriented in a different direction, and with a transferring system for transferring the pallets from the first to the second conveying line. The transferring system is provided in the form of a driven linear conveying track (5) for receiving the pallet(s) (2) from the first conveying line (3), for linearly advancing it/them on the linear conveying track and for transferring the pallet(s) to the second conveying line (4). The linear conveying track can swivel around an essentially vertical axis (7) between the first and the second conveying line via a driven swivel device (6). The vertical axis is located outside of the conveying track center (m) of the linear conveying track (5).

Abstract: Apparatus for the alignment of a plurality of bottles whose body is in the shape of a parallelepiped, and which are furthermore oriented in such a manner that said bottles are provided with respective axes centered on to the respective mouth, and the respective walls are inclined at either acute or obtuse angles with respect to the plane passing through said axes, in which there is provided a structure comprising two comb-like members (10, 11) and plurality of cylindrical cups (26) inserted in appropriate housings provided between said comb-like members (10, 11), wherein said cups (26) hold respective bottles (3) and are made in such a manner as to ensure that the corners of the bottles (3) are capable of being arranged in contact with the inner surface of said cups; said surface is in the shape of a plurality of plane surfaces spaced from each other by configurations in the shape of an arc of a circle having a radius (R) that is equal to the inner radius of the cups (r).

Abstract: Apparatus for reorienting containers such as bottles moving along and guided in single file along a plurality of side-by-side lanes in which the reorienting unit has a plurality of modular units each with an endless belt and operating in pairs to turn the containers a predetermined amount about a vertical axis in each of the respective lanes.

Abstract: A wood-edger for cutting away irregularities left on the edges of wood products, such as planks or boards, comprises a succession of different transferring mechanisms cooperating to regulate the flow of wood products to be processed and to properly position the same for the ultimate edging operation.

Abstract: A method for scanning a bar code printed on a tire and an equipment therefor are provided. The tire is moved in one direction, and the moving tire is sensed to stop at a predetermined position. Then, the tire stationed at the predetermined position is rotated to scan the bar code of the tire using a scanner fixed so as to scan only a part of the tire and then the tire is moved in one direction to be withdrawn from the predetermined position, thereby the bar code directly printed on the tire is accurately scanned.

Abstract: A wood-edger for cutting away irregularities left on the edges of wood products, such as planks or boards, comprises a succession of different transferring mechanisms cooperating to regulate the flow of wood products to be processed and to properly position the same for the ultimate edging operation.

Abstract: A conveyor system having an endless conveying surface, a plurality of diverters, and diverting shoes transversely movable across the conveying surface, includes a diverting track network in operational connection with a controller. The controller measures the length of each package, while the diverting track network includes a plurality of upstream diverting tracks and at least one downstream diverting track. The controller selectively actuates a diverter associated with downstream diverting track and at least one diverter along a particular upstream diverting track to engage the package proximate to its leading and trailing end.

Abstract: The invention relates in the first instance to a method for rotating an article which has an underside and lateral surfaces, more particularly for rotating a folding carton having the shape of a cuboid. The article is conveyed along a first lane (1), then rotated in order to re-align the article, and then conveyed along a second lane (2) which extends in the direction of the first lane. The rotation of the article takes place under the action of an element (30) which is in contact with a lateral surface of the article. To enable the rotation of the article to take place in a very tight space at a high conveying speed, it is proposed that the contact element (30) moves in the direction of the lanes (1, 2), being moved against the rear lateral surface of the article, based on the direction in which the article is being conveyed, and being in rolling contact therewith (roller 39).

Abstract: A device for orientating bottles in labeling, filling, capping machines and the like, comprising a turning element which is adapted to turn the bottles about an axis perpendicular to the conveyor belt until the intended position is reached, by making contact with the body of the bottles, and coordinated devices which are adapted to keep the head of the bottles in position during the orientation operation.

Abstract: Device for the alignment of tube segments, especially with several stagger-cut layers of paper at the ends, exhibiting mutually parallel first conveyor belts on which the tube segments lie with their wide sides facing the direction of travel, as well as second conveyor belts carrying stops arranged at preset intervals, wherein conveyor belts are aligned at an angle relative to the direction of travel. The first conveyor belts are aligned in the direction of travel and the second conveyor belts at an angle relative to the direction of travel. The stops on the second conveyor belt are entrainment devices designed to engage the back wide side of the tube segments, their purpose being to push an end of the tube segment on the first conveyor belt up to a sensor that operates without making contact. A signal from the sensor triggered by the end retards the second conveyor belts, which is leading first conveyor belts, in such a way that further transport will be taken over exclusively by the first conveyor belts.

Abstract: In the case of a machine installation for sterilizing, filling and closing containers it is provided that the above named devices are arranged together in a station, which is, with regard to drive, independent of the mechanism for feeding and removing the containers. A plurality of such stations can be provided, which preferably comprise a plasma sterilizing reactor.

Abstract: A belt conveyor comprises an endless conveyor belt and first and second rollers. The endless belt follows a conveyance path from the first roller to the second roller and a return path from the second roller to the first roller. The belt conveyor further comprises a plurality or parallel lines extending over the conveyor belt along the whole conveyance path and over and away from the second roller along a plane deviating from the plane of the conveyance path. The belt conveyor may be used in a food treating apparatus having a housing for conveyance of articles therethrough, and the housing may be used for treating, e.g. freezing, food products by impingement means.

Abstract: A robotic palletizing apparatus includes a conveyor and retractable product support having a support surface controllably extending beyond one end of the conveyor to support the bottom of an article beyond the conveyor end and retracting from the extended position such that the article supported thereon falls substantially flat from its otherwise supported condition.

Abstract: An apparatus and method for breaking connector elements between a rotatable shell and a base of a label affixed to an article. A first belt transports a labeled article at a first rate. A second belt holds the article in a nonrotatable position relative to the first belt. A third belt, advancing at a second rate different from the first rate, selectively contacts the rotatable shell of the label, causing the connection ties between the rotatable portion and the base portion to break, permitting the shell to rotate relative to the base portion.

Abstract: An unscrambling and aligning conveyor comprises a plurality of tapered rollers attached to a pair of side supports. The tapered rollers are driven at a single speed and tapered to a minimum diameter to define an alignment region. The tapered rollers create a lateral speed decrease toward the alignment region of the conveyor, causing separation and rotation of the articles, and thereby enabling the articles to be singulated in the alignment region. The tapered rollers are supported by the side supports such that center axis of each roller is horizontal to thereby defining a downwardly sloping article transport surface which increases movement of the articles towards the alignment region. The unscrambling and aligning conveyor is driven at a speed greater than the input conveyor located adjacently upstream thereof to provide articles with a gap therebetween so that articles moving along the unscrambling and aligning conveyor are properly singulated.

Abstract: A Method of stacking product directly from a conveyor, comprising the steps of conveying a product toward the end of a conveyor; supporting a leading edge of the produce as the leading edge exists the conveyor; releasing the leading edge and a following edge of the product with such timing as to cause the product to fall substantially flat onto a platform; and articulating the conveyor, whereby product is stacked in a pattern.

Abstract: A method of turning boards (2) comprises the steps that the boards (2) are transported on a conveyor (1) with conveyor dogs (4), with their longitudinal direction transverse to the conveyor (1). The boards (2) are accelerated relative to the conveyor (1) until the front edges (13) of the boards (2) abut against the rear edge (14) of the next dog (4). Lifting devices (16) which move synchronously with the conveyor (1) lift the front edges of the boards (2) at the same time as the boards (2) are moved towards the lifting devices (16), whereby the boards (2) are turned with their front edges facing upwards and backwards. An apparatus for turning boards comprises a first conveyor (1) with dogs (4) for transport of the boards (2), and a second conveyor (11) with an upper part (12) which, on the first conveyor (1), shunts the boards from one dog (4) to the next.

Abstract: A method for the positionally accurate feeding of sheet-like objects to a treatment process, the objects being conveyed in succession in a lying position and being aligned during the conveyance. Rotational movement of the conveyed object is carried out to correct a skew position of the front edge of the object, a lateral movement of the object is carried out transversely, in particular at right angles, to the conveying direction for lateral alignment purposes, and an accelerated or decelerated longitudinal movement in the conveying direction is carried out for longitudinal alignment of the object, all the alignment movements being carried out on the surface of an object and without any mechanical alignment action on one or more peripheral edges of the object.

Abstract: In order to inspect objects (10), particularly drinks bottles, these are transported on two conveyors (12, 14), which exhibit a mutual lateral separation and run at different speeds, so that the objects (10) rotate about their vertical axis. Within the distance separating the conveyors (12, 14) a bottom checking installation (30, 32) is provided. A rail (16) for guiding the objects (10) can be arranged, stretching in the direction of transport above the first, slower-running conveyor (12), in such a way that the objects (10) on the first conveyor (12) stand on the edge strip between the rail (16) and the edge of the first conveyor (12), and the width of this edge strip amounts to up to about ⅓ of the diameter of the objects.

Abstract: Method and apparatus for orienting a container, or plurality thereof, incident to a packaging operation by engaging the container with an elongate driven member travelling at a different speed than the container along a conveyor or assembly line. In particular, the containers may have the shape of a petaloid bottle, for beverages and the like, and the bottles are rotated into a common position to conform to requirements of the carton, carrier or other packaging material.

Abstract: A conveying device for sheet-like workpieces having low specific gravity (21), such as paper or cardboard, comprises two median conveying elements (11, 12) arranged side by side along the path of the workpieces (21), for changing the orientation of the sheets or plates about a perpendicular axis. Separate drive mechanisms with adjustable speed (18) are connected to each of the median conveying elements (11, 12). A plenum (22) provided with a fan (23) is used to apply a downward air pressure to the workpieces (21), pressing them against the median conveying elements (11, 12) in order to transmit different speeds to each of the surface parts of the workpieces (21) in contact with the respective conveying elements (11, 12).

Abstract: A laned conveyor apparatus includes an infeed roller and an outfeed roller rotatably mounted to a frame in spaced apart relation for movably supporting a flexible product-carrying belt that forms a closed loop about the rollers to define a conveying region having a length and a width. A plurality of elastic separating bands are removably positioned around the rollers and the product-carrying belt and spaced apart at intervals along the width of the conveying region to form lanes along the length of the conveying region. The separating bands contact an outer surface of the product-carrying belt to form a frictional interface with the product-carrying belt that causes the separating bands to move in coordination with movement of the product-carrying belt. A guide mechanism mounted to the frame includes multiple guide features spaced apart at intervals along the width of the conveying region for guiding the separating bands so that the lanes are accurately and precisely positioned in relation to the frame.

Abstract: In a device for aligning objects, particularly sausages (1), which are fed for instance to a packaging device (7), at least two elements (14, 15) moving opposite each other are arranged approximately parallel to each other. They leave between them a space (16, 17) through which the objects (1) can drop.

Abstract: A plate alignment station (24) for advancing a series of plates and for adjusting the orientation or alignment of the plates as they are advanced. The alignment station includes a conveyor (140) having a pair of side-by-side conveyor chains or belts (142, 144) and a pair of servo assemblies (146, 148) each coupled with one of the chains or belts. The servo assemblies can be operated to advance or retard one of the conveyor chains or belts relative to the other to adjust the orientation of plates supported on the conveyors.

Abstract: A conveyor diverting system having an endless conveying surface and diverting shoes transversely movable across the conveying surface for diverting articles having an upstream and a downstream diverting track where the upstream diverting track is oriented parallel to the downstream diverting track for a portion of its length, and converges with the downstream diverting track along its other portion. The conveyor system further includes a controller which utilizes only the downstream diverting track if the article to be diverted is less than a first predetermined length or greater than a second predetermined length. If the article to be diverted is between the first predetermined length and the second predetermined length, then both diverting tracks are utilized.

Abstract: A conveyor diverting system having an endless conveying surface and diverting shoes transversely movable across the conveying surface for diverting articles having an upstream and a downstream diverting track where the upstream diverting track is oriented parallel to the downstream diverting track for a portion of its length, and converges with the downstream diverting track along its other portion. The conveyor system further includes a controller which utilizes only the downstream diverting track if the article to be diverted is less than a first predetermined length or greater than a second predetermined length. If the article to be diverted is between the first predetermined length and the second predetermined length, then both diverting tracks are utilized.

Abstract: The articles to be turned round are advanced on conveyor means having a downstream portion which is intended to support one end of each article and is located in a generally raised position projecting over a successive conveyor portion. In the region of the downstream portion, the articles are held in an inclined position, supported at their ends. This allows a turning movement to be brought about as a result of the speed difference between the downstream end and the successive conveyor portion.

Abstract: A machine for positioning and leveling plates for electric accumulators, is operationally arranged downstream of a machine for separating lead grids (2), initially formed by a continuous strip (5), into pairs of plates (11). The machine in question is substantially provided with an upstream section (16), a central section (20) and a downstream section (17) associated respectively with first (18), second (21) and third (22) conveying devices. The first conveying device (18) removes the plates (11) from the separating machine (2) and transfers them, through a compression station (19) to level the plates (11), to the central section (20).

Abstract: The present invention pertains to an improved belt and pulley conveying apparatus for conveying bottle containers. The conveying apparatus comprises a set of belts each driven by a pair of pulleys with a lateral spacing between the belts dimensioned to receive bottle containers therebetween. The belts engage the bottle containers and convey them from an input conveyor to a diverter assembly. The apparatus includes a plurality of motor driven shafts, each shaft having a plurality of the pulleys adjustably mounted thereon. The positions of the belts are horizontally and vertically adjustable thereby allowing the conveyor to accommodate containers of various dimensions.

Abstract: An infeed conveyor for a packaging machine having a first squeezer conveyor including upper and lower belts spaced to receive workpieces in an end-to-end relationship. Upper speed-up rollers and lower speed-up rollers advance the workpieces further along the path of the first squeezer conveyor. A second conveyor being provided for receiving the workpieces from the speed-up rollers. A third conveyor being positioned above the second conveyor and operating at a lower rate of speed whereby when an upper leading edge of a workpiece engages with the third conveyor, the workpiece is rotated approximately ninety-degrees from its previous orientation. Flight bars rotate with the second conveyor at a rate faster than the second conveyor thereby bunching the workpieces into abutting groups of a predetermined size for entry into a packaging machine.

Abstract: An apparatus for rotating substantially flat articles being transported along a production line is provided. The apparatus is configured so as to rotate the articles, about an axis extending substantially perpendicular to the direction of transport of the articles, through a desired number of degrees of rotation, while permitting the articles to be transported along the production line in a substantially uninterrupted and unimpeded manner.

Abstract: To turn through 90.degree. sheets passing at a rapid rate over a roller conveyor in a horizontal plane, a device is proposed which comprises a pair of rollers entrained in rotation at different speeds and spaced apart from each other and from a longitudinal guide on the conveyor transversely with respect thereto. Each of the rollers has its rotation axis inclined with respect to the normal on this guide, by a specified angle which is greater for the roller which is closest to the guide and the rotation speed of which is the smaller. Each of the rollers has its periphery in contact with a support ball or with the lower face of a sheet during its passage, substantially in said transport plane.