FR2464192A1 - Velocity compensator assembly in horizontal article conveyor system - has several gripping members positioned by carrier bars and includes control arms - Google Patents

Abstract

The article packing or unpacking appts. includes two correlated driven conveyors one for articles and one for moving cases through a fixed course having a horizontal section and with both conveyors having fixed orbits. The article conveyor is in a vertical plane above the one conveyor horizontal section. Article grippers are positioned by carrier bars engaged with the article conveyor, which grippers depend from the carrier bars in a lower reach of such article conveyor. A pair of control arms are individually secured to each carrier bar at different ends to engage guides as the article conveyor is moved downwardly towards an inflection area so that the article grippers are presented on vertical axes as they are moved into, along with, and lifted from cases moving through the horizontal section of the case conveyor fixed course.

Description

 It is well known that the non-alcoholic beverage and beer industry, as well as other industries, process a very large number of bottles or other containers every day and that the processing machinery used for this purpose and constructed and currently marketed must operate quickly and safely and reliably to completely fill crates with items to be packaged in these crates, and to remove all items from the crates to be unloaded. The machine must also be able to be easily adjusted for handling crates of different dimensions. Continuous efforts have been made to increase the working speed of machines for crating and removing articles and bottles from crates, as well as the reliability and efficiency of such machines. US Patent No. 3,951,285 discloses a machine designed to automatically lift containers, in particular bottles, moving crates, and then to deposit them on another conveyor placed at a distance. This machine has several automatic clamps very close together, moving along a closed circuit that passes over one or more moving boxes to be emptied.

This machine causes the clamps to follow a fixed circuit including a path down to a lower point or inflection at which the clamps take the articles before changing direction while climbing. It is stated in the aforementioned patent that the speed of the driving chains of the clamps on a circuit inscribed in a vertical plane must be slightly greater than the speed of the conveyor controlling the movement of the full boxes in the machine, so that these chains have a horizontal component of speed equal to the speed of displacement of the-carrier carrying crates.

 This prior machine uses a plurality of fingers or clamping members, constituting the clamps, and maintained substantially in fixed longitudinal positions within the control mechanism. No device makes it possible to place the members of the clamps in positions corresponding to those of the articles in a box to be loaded or unloaded.

 The invention relates to a device for gripping or gripping articles intended for a machine for removing bottles from their crates, and to similar machines in which the article gripping devices are arranged in groups corresponding to the articles to be put in place. in place in a crate or withdrawing from a crate, so that it is possible to obtain a precise alignment and a precise gripping action of the articles, and also so that the gripping devices move on a determined circuit and to a corresponding velocity, in the inflection zone, to the speed of the movement of the articles placed in the full crates.

 The invention also relates to the mounting of gripping or gripping devices on support bars arranged transversely in the machine and to which the gripping devices are suspended at a fixed angle, so that the orientation of these devices with respect to the vertical can be adjusted by means of support bars coupled to controlled conveyors.

 The invention also relates to two control arms engaged with each support bar of gripping devices in an article processing machine.

Each support bar, which is pivotable, is controlled to place the article pickup device, carried by this bar, on a vertical axis during movement of the bar to the point or area of inflection and also during the passage. of this bar at this point or in this zone, as well as beyond it. The two control arms determine the positions of the support bars and the devices for gripping articles carried by these bars when these devices pass through the deposition and / or release points of the article X, or in certain parts of the apparatus, while possibly allowing a global action of control of the bars and the positioning of the latter on the remaining part of the closed circuit followed by these bars1 as a function of the drive conveyors. The arms use mechanical members which require minimal maintenance and which allow to effectively control the position of the gripping devices in a machine intended to put items in the crate and empty crates of their articles. Pentograph mechanisms, control chain mechanisms and guide rolls of support bars, placed on common axes, are also positioned, as are the support bars mounted on axes located radially inwardly of the circuit. of the conveyor, in order to facilitate the adjustment of the speed of movement of the gripping devices on the support bars in the zone or the point of inflection of the machine.

 The invention is also intended to improve the reliability, speed and efficiency of a machine for putting items in the box and removing items from a box.

The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting example and on which
Figure 1 is a schematic elevation of a machine according to the invention for removing items from a box
FIG. 2 is a diagrammatic elevation of the machine of FIG. 1, showing a device for gripping articles held on vertical axes in certain parts of the closed circuit followed by this device
Fig. 3a is a partial schematic elevation showing support bars, article grippers and a control mechanism moving toward the inflection and article gripping zone of the article transport circuit.
FIG. 3b is a partial elevation, similar to that of FIG. 3a, showing the same elements moving away from the inflection zone
FIG. 4 is an enlarged partial cross-section of a support bar and an article gripper, as well as their associated assembly and control devices, forming part of the machine according to the invention; ; and
FIG. 5 is a perspective view, with a partial vertical section, of a detail of the machine comprising in particular an article gripper, a support bar and associated mounting elements, as well as a pantograph mechanism; .

 The corresponding elements have the same numerical references in the different figures.

 An embodiment of the invention is a box unpacking machine comprising a frame, a controlled conveyor for moving the full boxes on a fixed stroke comprising a horizontal section, and a controlled article carrier moving on a fixed circuit, in a vertical plane, above the horizontal section of the crate conveyor, article gripping devices and support bars of these devices, connected to and moved by the article carrier, the taking off normally from the support bars with which they form a fixed angle. The improvement of the machine according to the invention is constituted by the presence of two control arms associated with each of the support bars, separately fixed at different ends of the bars from which they depart in planes perpendicular to the longitudinal axis of these bars . The article carrier follows a path down to the horizontal section of the crate conveyor stroke forming an acute angle with it and then rising from an inflection zone located inside the machine. so that the ascending section forms an acute angle with the horizontal. This inflection zone is located in the engagement zone of the devices for gripping a support bar with an article placed in a crate carried by the conveyor. The frame carries guide members which come into contact with one of them. control arms as the associated support bar descends to and passes through the inflection zone and contacts the other control arm when the same support bar rises from the inflection zone so that the article grippers can be held in vertical positions as they move toward the inflection zone and move away from them to facilitate engagement with the articles and removal of the articles from their crates transport.

 In the article packaging or unpacking machine according to the invention, the crate advance control device is advantageously of the type described in US Patent Application No. 879,129, filed on February 21, 1978. The bottle-setting devices used in the machine according to the invention may be of a conventional type, but it is, however, preferred to use the devices described in United States Patent Application No. 845-460.

The machine according to the invention comprises support bar assemblies and grippers described and shown in United States Patent Application No. 879,128, filed February 21, 1978. The closed circuit conveyor, forming the part of the machine carrying articles, is described in detail, as well as its operation, in United States Patent Application No. 879,130, filed February 21, 1978, and relating to an adjustable device for loading and unloading crates.

 The figures show a machine 10 for unpacking articles whose main elements will be described in detail. This unpacking machine crates or articles comprises a conventional frame 12 and a controlled conveyor 14 for moving crates 16 on a fixed path comprising a strand or horizontal section 18 which passes on the frame. The conveyor 14 the frame 12 and the section 18 are shown schematically in Figure 1.

The entire machine and frame is schematically countered in Figures 1 and 2 and it comprises a fixed support for mounting the various elements of the machine in positions allowing them to cooperate with each other. These elements include a second driven conveyor or article carrier positioned above the horizontal section 18 of the crate conveyor, as shown in FIG. 1. The article carrier positions and controls a plurality of article gripping devices 22 which are carried and positioned by support bars 24 (Figure 4) arranged transversely to the machine and, more particularly, to the closed circuit followed by the conveyor 20 and the vertical plane defined by the latter.

 The article conveyor 20 is intended to take suitable articles, for example bottles 26> from the crates 16 and lift them from the latter to a second section of the conveyor circuit near which a horizontal conveyor 28 is placed to receive the items. The conveyor-20 and the associated mechanism are adapted to deposit the articles 26 on the receiving conveyor 28 so that the latter conveys said articles to other stations in which any desired processing is performed.

 The devices 22 for taking articles occupy adjustable positions so that it is possible to adapt the machine to work on boxes 16 of different sizes and types. Groups of article-catching devices, intended to engage with the crates, are placed at suitably spaced points along the conveyor 20.

 Figures 4 and 5 show control arms 30 and 32 and other details of the apparatus associated with the support bars 24. These control arms 30 and 32 are attached to each support bar 24, on shafts 25 at opposite ends of the bar, so that the arm 30 makes an obtuse angle in a first direction with the longitudinal axis of the bar. 24 and that the arm 32 makes an obtuse angle, in the opposite direction, with the same axis of the bar, at the end of the latter opposite to that carrying the arm O. n addition, the control arms are normally contained in planes they define and which are perpendicular to the longitudinal axes of the support bars. A roller or guide member 34 journals on each control arm. The bars 24 normally have a substantially planar inner or upper surface 36 and upper end sections or fingers 38 of the article gripping devices protrude through these bars. The article gripping devices 24 are resiliently mounted on the support bars and the fingers 38 can be lowered to the bars to control the opening and closing movements of jaws 39 forming part grippers to the part. The support bars 24 are positioned inside the unpacking machine by means of elements such as those described in the above-mentioned United States Patent Application No. 879,130 and comprising consoles 40 which go down the bars and which pivot on the ends of the latter, and two members or guide rollers 42 which are journalled on the consol-es 40 and which are fins to bear against wings 44 and 46 These wings are suitably fixed to the frame 12 to determine the fixed circuit on which the support bars 24 are moved by the article conveyor 20. This carrier 20 comprises two 20a and 20b described in more detail in the above-mentioned United States patent application N 879 130, and a second type of console 41 bears against the bars 24, between the ends of a group of these bars intended to engage with a crate, to carry them and to follow the circuit of the carrier 20.

 To carry out the required forced control of the support bars 24 and the gripping devices 22 that they carry, the rollers 34 of the control arms 30 and 32 bear, as shown in FIG. 4, against two cam tracks or paths 4 and The tracks or cam tracks are arranged at a variable spacing from the axis of the control conveyor circuit 20 passing the articles through the box unpacking machine as will be described hereinafter.

 FIG. 4 shows the circuit followed by the article conveyor 20, while FIG. 2 shows the two guide tracks 48 and 50 on the right descending segment aa of the conveyor, when approaching a point or an inflection zone situated at the lowest part of the conveyor circuit 20 and in which the action of removing or depositing the articles is carried out according to whether the machine carries out a collection of articles or articles removed from the articles. FIG. 2 shows that the path 50 is longer than the path 48 so that the roller 34 of the control arm comes into contact with the first path 50 and is placed between the paths 48 and 50 to effectively control the the angle formed by the control arm with the vertical when the support bar 24, to which it is connected, goes down to the inflection zone. The cam paths gradually pivot the arm 30 backwards so that the support bar rotates slightly on its longitudinal axis as the conveyors 20a and 20b move it towards the inflection zone.

This results in a change in the position of the gripping devices 22 so that they are desirably maintained on vertical axes as the support bars 24 move towards the inflection zone of the machine and pass into this zone. It should be noted that these bars move from inclined positions, taken upstream of the inflection zone, to horizontal positions in this inflection zone.

 Another important feature of the guiding and controlling device of the machine according to the invention is the presence of two other tracks or cam or guide tracks 52 and 54 mounted on the frame, along the rising section of the circuit of the machine. carrier 20, beyond the inflection zone. At this time, the conveyor 20 rises along a rectilinear path forming an acute angle with the horizontal. The opposite control arm 32 of each support bar is engaged with these plates or tracks 52 and 54 of the cam.

 Figures 2, 3a and 3b show how the arms 30, shown schematically as being on the lateral side remote from the machine 10 of the invention, form a certain angle facing downstream or towards the rear of the closed circuit followed by the conveyor 20, while the control arms 32, shown on the near side of the machine, form with the vertical angles oriented substantially upstream of the circuit followed by the conveyor 20. The frame and the associated elements are not shown in FIG. 2 so that the latter mainly represents the position and guiding control elements. The distance between the cam tracks 52 and 54 and the axis of the conveyor circuit 20 varies as for the tracks 48 and 50 of FIG. cam, so that the angle formed by the control arms 30 and 32 and the vertical and, therefore, the position in which the control rods 24 pivot vary slightly on the asc section. carrier to maintain on vertical axes the devices 22 for gripping items, hanging or running down the bars. When the support bars are raised by the conveyor 20 passing over a toothed wheel 56, the conveyor 20 executes a movement passing it, by a progressive curve, from a substantially straight ascending section to a substantially horizontal section 58 situated above and in the immediate vicinity of the article delivery conveyor 28. The feed speed of the gripping jaws and their gripping devices is such that the gripping devices 22 move horizontally at the same speed as the conveyor 28. so that items are deposited gently on the latter to be processed.

 It is desirable to hold the grippers 22 in relatively fixed or determined positions as they are moved over the idle portion of the conveyor circuit 20. Therefore, a suitable control rail or other cam member 60 is to the frame 12 so as to come into contact with the flat surfaces of the support bars 24 and to maintain the latter in a fixed position relative to the conveyor 20 as they travel through the upper section of the circuit of this conveyor, the bars being then released so as to be able to pivot separately and in a determined manner in order to position itself when the conveyor attacks its downward stroke after having passed over a toothed wheel 62.

 The conveyor 20 is controlled and / or adjusted by means of elements described in more detail in the aforementioned U.S. Patent Application No. 879,130.

 The jaws of the article grippers are open when the fingers 3a descend, but the elastic return of the gripping devices 22 normally causes the jaws of the grippers and / or the fingers 39 to engage with an article or restraint-of an article.

 To control actions of gripping and release of an article, suitable flat cams of known design are used in the machine 10 according to the invention and fixed to the frame 12. A typical flat cam 64 of control, shown on FIG. 1, is intended to come into contact with the upper ends of the fingers 38 when the support bars 24 descend towards the inflection zone by following the conveyor circuit so as to bear against this cam which is placed above and to immediate proximity of the inflection zone of the machine.

As a result, when the grip jaws move to the grip positions in the inflection zone, they open, but the flat cam 64 terminates at this point and allows the jaws 39 to be closed again. by a spring to a gripping position of an article. By traversing the rectilinear ascending section, the carrier 20 then raises the articles of the associated boxes 16, as well as the axes, held vertically, gripping devices.

 A flat cam (not shown) identical to the flat cam 4 is mounted near the toothed wheel 56 to contact the fingers 36 of the article grippers to move the jaws to the open or release position. articles while the gripping devices 22 and their support bars arrive on the gear wheel and deposit the articles on the conveyor 26. The cam tracks 44 and 46 are obviously designed to establish the desired and closed circuit for the conveyor 20.

 It is obvious that the machine according to the invention makes a forced and precise control of the positioning of the devices 22 for gripping articles associated with the support bars 24, since the latter are displaced so as to traverse the zone or point of inflection of the machine while the gripping devices have been lowered into the boxes to take the items contained therein to then lift the crates when the carrier 14 advances them below the closed circuit followed by the conveyor 20 The articles are removed from the crates smoothly and easily, since the gripping devices 22 remain vertically oriented as they approach the inflection point and move away from it.

 In order for the support bars to be constantly and continuously controlled, the machine comprises the control arms and the wings 48 and 50 which firmly determine the exact position in which the support bars 24 are turned as they descend towards the inflection, located at the lowest point of the circuit followed by the carrier, and when they cross this zone. However, the control arm disengages from these flat control cams immediately after the opposite control arm 32 (FIG. 3a) has been brought into contact with one of the flat cams 52 and 54, and in general both.

Therefore, in this position X, the control bar 24a is held so as to be unable to pivot on its axes 25 so that the gripping devices remain aligned vertically after being moved upstream of the conveyor circuit, following a curve, holding the gripping devices in vertical position resulting from the change of the angle formed by the control arm with the vertical.A present that the support bar 24a of the gripping device begins to rise in the machine, it is maintained by its opposite control arm 32 and by its rolling, by means of the rollers, on the paths 52 and 54 of cama, in a desired position with respect to the longitudinal axes of the support bars and / or with respect to a line vertically passing through the longitudinal axes of the support bars, this position pivoting gradually, so that the devices 22 for gripping articles are maintained on vertical support axes for co mmander efficiently the setting and the laying of the articles by the machine.

 No cam track is in contact with the control arms 30 and 32 along the remaining portion of the circuit followed by the conveyor 20, from a point near the conveyor 28, and the arms can therefore move freely and without opposition within the machine, since the flat cam or the guide member 60 controls the actions and positions of the support bars with respect to the conveyor circuit 20.

 Figures 3a and 3b schematically show the main position control elements forming part of the machine, and show the progressive changes of the relative positions of the control arms 30 and 32 on the support bars 24. It is obvious, in practice, that the bars 24 are connected to the conveyor in groups spaced apart from each other along the circuit followed by this carrier. The bars 24 have a roughly rectangular vertical section and the grippers can move on their vertical axes relative to the support or mounting bars, but they can not rotate around the axis of the bars, so that fixed assemblies constituted by the control arms, the bars 24 and the gripping devices 22 are presented to the boxes 16 to take the articles.

As described in detail in the aforementioned U.S. Patent Application 879 28, the article gripping devices 22 can be moved laterally with respect to the support bars 24 and, therefore, when these bars pass sprockets 56, conventional and suitable guiding grooves or other elements similar to those described in the US Pat.
United States of America No. 3,951,285 engages with the fingers 3a and controls the position of the devices 22 for gripping the support bars laterally. The gripping devices can be very close to each other laterally after passing over the pinion 56, then they can again be positioned laterally on the support bars in correlation with the transverse rows of articles formed in the boxes 16 to be treated.

 The machine according to the invention forcibly controls the positions in suspension of the devices 22 for gripping articles, downwardly from the support bars 24, while the carrier travels the section a-a. The de-tapers 22 are moved progressively over m, n and o angles of decreasing amplitude to the vertical, and then they are placed on a vertical axis.

 It should be noted that since the centers of the movements of the support bars 24 are internal to the closed circuit followed by the article conveyor 20 and the associated positioning elements, the gripping devices 22 move slightly closer to each other. when the conveyor 20 for driving and driving the articles descends to the zone or point of inflection of the machine and crosses it while turning. However, the pitch "x" of the gripping devices remains substantially constant, which facilitates the introduction of these devices in the associated boxes and taking bottles or items they contain. It also appears that the speed of the chain conveyors is constant and that the speed of the support bars 24 is less than that of the conveyor 20 in the inflection zone. However, the support bars have in the inflection zone a horizontal speed approximately equal to that of the transporter 18 crates.

 It should be noted that any suitable angular relationship can be established between the straight downward inclined section of the conveyor 20 and the horizontal.

In all cases, the relative speeds of the crate conveyor 14 and article conveyor 20 must be set relative to each other so that the horizontal movement of the support bars 24 and the gripper 22 The articles, as they pass through the bending zone of the machine, are substantially or almost exactly the same as those of the crates entrained in the machine by the conveyor 14.

 All the support bars 24 are controlled by the conveyor, even if they are not fixed directly to the latter, because a pantograph mechanism P forms sets of several support bars 24 comprising mounting members and drive, as shown in Figures 4 and 5, this mechanism being also placed at the other end of the bars. It should be noted that the brackets 40 are placed at each end of a pantograph mechanism and attached to the conveyor members 20a or 20b, as shown in FIG. 4.

 It follows from the preceding description that the machine according to the invention provides a firm and efficient mechanical control for holding the devices 22 for gripping articles and fingers or jaws for gripping articles in vertical positions inside the machine. the machine.

This result is obtained by the cooperation of the support bars 24, the control arms 30 and 32, the brackets 40 and 41 and the rollers 42, and by the positions of the conveyor 20 and the longitudinal axes of the rollers 42 with respect to the normal plane. The pantograph mechanism P is used to connect a plurality of support bars to form a group of bars for association with a box.

As a result, the article feeder fingers are assembled into e1x 3 '~. in groups corresponding to the groups of articles contained in the boxes R treat. It should be noted that the progressive positions taken by a control arm are shown schematically in FIGS. 3 and 3b and that the set of paths 40 and 50 is on a lateral side of the machine different from that of the set of paths 52 and 54, as shown schematically in FIG.

 The machine mechanically and firmly controls the positions of the grippers to improve the removal of crate items. It allows to meet the requested criteria in a fast and automatic way.

 It goes without saying that many modifications can be made to the machine described and shown without departing from the scope of the invention.

Claims (12)

EVIDENCE A packaging and unpacking machine for articles, comprising a frame, a driven wagon for moving crates on a fixed stroke comprising a horizontal section, and a driven conveyor which follows a fixed circuit, contained in a vertical plane, at above the horizontal section, the machine also comprising article gripping devices and support bars of these devices, connected to the fixed circuit conveyor and moving with said conveyor, the downward gripping devices bars with which they form a fixed angle in a lower strand of the conveyor circuit, the machine being characterized in that it comprises two control arms associated with each support bar and fixed at the opposite ends of this bar from which they leave in planes perpendicular to the axis of the bar and in different directions at obtuse angles equal to the longitudinal axis al of the bar, the conveyor leads to a fixed circuit following a path that descends to the horizontal section forming an acute angle with it, then which rises from a zone of inflection, also forming an acute angle with the section horizontal, the inflection zone corresponding to the engagement zone of a gripping device with an article in a box placed on the conveyor intended to move the crates, the frame carrying a guiding device intended to come into contact with one control arms when the associated support bar descends to the inflection zone, the guiding device contacting the other control arm when the associated bar rises from the inflection zone, so that the gripping device can be held vertically as it moves toward and away from the inflection zone.  2. Machine according to claim 1, characterized in that it comprises a control mechanism of the crate conveyor at a fixed speed, a control mechanism of the article carrier at a speed greater than that of the crate transporter, the bars the carrier being positioned internally to the article carrier circuit and the latter being adapted to move a support bar and the associated gripping device at a horizontal speed, in the inflection zone, substantially equal to that of the crate conveyor.  3. Archine for emptying crates, comprising a frame, a driven conveyor for moving full crates on a fixed stroke comprising a horizontal section, and a driven conveyor, in a fixed circuit contained in a vertical plane and located above the horizontal section of the crate conveyor, the machine also comprising article gripping devices and support bars of these devices, connected to and moving with the fixed circuit conveyor, gripping devices support bars by forming with them a fixed angle, the machine being characterized in that it comprises two control arms separately attached to the opposite ends of each support bar and starting from the latter in planes perpendicular to the longitudinal axis of the bar, the fixed circuit conveyor following a stroke down to the horizontal section with which it forms an angle the inflection zone being the zone in which a gripping device engages with an article placed in a box resting on the conveyor of boxes, the frame carrying a guiding device intended to come into contact with one of the control arms when the associated support bar descends towards the inflection zone and passes into the latter, this guiding device coming into contact with the another control arm when the associated support bar rises from the inflection zone, so that the corresponding gripping device can be maintained in a vertical position by moving towards the inflection zone and away from it.  4. Machine according to claim 3, characterized in that the control arms leave the support bars in different directions and forming obtuse angles with the axis of these bars, the arms being oriented towards the inside of the circuit of the carrier and the angle formed by each arm with the horizontal varying as the support bar descends to the inflection zone.  5. Machine according to claim 4, characterized in that the control arms hold the article gripping devices on vertical axes by pivoting the support bars, the latter being controlled by the arms which perform a curved motion determined by the guide device which bears against the inner ends of said control arms.  6. Machine according to claim 3, characterized in that it comprises a mechanism for driving the crate transporter at a fixed speed and a mechanism driving the other carrier at a speed greater than that of the first mentioned carrier, said other carrier along a curved path in the inflection zone, the support bars being connected to this other conveyor so as to be placed radially inwardly of the curved path and thus to advance at the rate at which the crate conveyor passes close of the inflection zone.  7. Machine according to claim 3, characterized in that a bracket is articulated on each end of the support bars, two rollers journalling on this console, on a portion of the fixed circuit of the carrier located radially outwardly relative to at the position of the support bars, guide wings, mounted on the frame, intended to come into contact with the rollers and to define the circuit followed by the support bars.  8. Machine according to claim 7, characterized in that it comprises a chain control mechanism forming part of the conveyor 4 ixe circuit, the rollers being mounted on axes aligned with certain parts of this control mechanism.  9. Tachine according to claim 3, characterized in that it comprises guide cams mounted on the frame and intended to come into contact with the support bars on part of their circuit, and hold them in a fixed position relative to to the fixed circuit carrier, the control arms contacting the guide device along the remaining portion of the conveyor circuit.  10. Machine according to claim 3, characterized in that the guide device mounted on the frame comprises two descending flat cams and two ascending flat cams, the control arms carrying rollers intended to come into contact with the cams to adjust the cams. positions of the support bars which are rotatably mounted on their longitudinal axes.  1. A machine for removing articles from a crate, comprising a frame, a driven conveyor for moving full crates on a fixed path comprising a horizontal section, and a second driven conveyor which -suits a fixed circuit, in a plane vertical, above the horizontal section, the article gripping devices and support bars for these devices, connected to and movable with the second conveyor, the support bars being pivotable on their longitudinal axes, the machine being characterized in that it comprises two control arms separately attached to the opposite ends of each support bar, the second conveyor following a path which descends towards the horizontal section with which it forms an acute angle, then which rises from a zone of inflection, also forming an acute angle, this inflection zone being the zone in which a gripping device engages with an article contained in a the crate placed on the first conveyor cited, the gripping devices down the support bars with which they form a fixed angle when the second conveyor down, a guide device mounted on the frame being intended to enter in contact with one of the control arms when the associated support bar descends to and enters the inflection zone, the guiding device coming into contact with the other control arm when the associated support bar pupil of the inflection zone, the guiding device modifying the angle formed by a control arm with the vertical so as to rotate the support bars on their longitudinal axes to control the devices for taking articles when the latter move closer and away from the inflection zone.  12. Machine according to claim 11, characterized in that it comprises a mechanism for advancing the first conveyor at a fixed speed, a mechanism for advancing the second conveyor on a closed circuit, at a speed greater than that of the first conveyor, the control rods being placed radially inside the fixed circuit of the second conveyor so as to be displaced downstream at a speed equal to that of the first conveyor at the inflection zone.  13. Machine according to claim 12, characterized in that each pair of control arm, the support bar to which these arms are fixed and the gripping device carried by this bar form a rigid assembly with respect to the rotational movement of the bar on its longitudinal axis, this movement being due to the spacing between the flat cams and the circuit of the second conveyor.  14. Machine according to claim 11, characterized in that the guide device mounted on the frame comprises two descending flat cams and two ascending cams, spaced longitudinally descending cams, and rollers mounted on the control arms and in contact with the flat cams to determine the positions of the support bars which are rotatably mounted on their longitudinal axes.