FR2507583A1 - Detector for conveyor belt speed control - has pivoting arm with contact foot which rotates shaft to activate detector elements through toothed wheel - Google Patents

Abstract

The items (1) are fed by a conveyor belt into a channel forming a descending path to a second downstream conveyor (3). At a section of channel with a constant slope, the height from the base (6) of the channel to the top (7) of the items is measured by a detector (16). This comprises an arm (21) to which a part (19) is attached to contact the items. The arm pivots about a transverse pivot axis (23) in side plates (15) and is attached to a toothed segmented element (25) whose teeth engage a toothed wheel (27) on a second axis. A longitudinal bar (29) fixed to the wheel has a sensor (17,18) at each end (31,32) to provide signals for a speed control circuit. This controls the speed of the feed conveyor to maintain a predetermined height measurement. The arrangement is partic. intended for conveying biscuits.

Description

 The present invention relates to a process for automatic regulation of the transfer in line of substantially identical parallelepiped products, such as cookies, between an upstream debtor device supplying the products on edge with constant compaction and an adjustable speed and a downstream receiver device taking them up with a constant step. The invention also covers a device for implementing the above method.

 The term “substantially identical parallelepiped products” means generally thin solid products having substantially identical geometrical dimensions, that is to say each comprising two parallel faces, separated by a thickness which may vary slightly from one product to the next, and having in cross section of identical shapes, for example rectangular, trapezoidal or circular, corresponding to a constant height for each shape of product The processed products can be rigid, for example cans, or fragile, for example cookies.

 In the field of file transfer at a high rate of such products, it is known that it is necessary to ensure a perfectly regular supply of the downstream receiver device, so that the products are presented to the latter in the position and rhythm. It is indeed obvious that a lack of products corresponds to an insufficient compaction allowing them to take a bad position preventing any correct recovery, while a jam corresponds to an exaggerated compaction also causing the immediate deterioration of a series of products in in the case of fragile products or part of the recovery device in the case of rigid products.

 The present invention aims to remedy these drawbacks by providing a method and a device making it possible to automatically regulate the transfer of products to the downstream receiving device, so that the supply thereof is free of gaps and jams.

 According to the invention, in the process of automatic regulation of the transfer in line of substantially identical parallelelipipedic products between an upstream debtor device supplying the products on edge with constant compaction and an adjustable speed and a downstream receiver device taking them up with a constant step , the products from the upstream device are slid into a gutter along a downward path towards the downstream device, whereby said products tilt by gravity, the height between the bottom of the gutter and the upper edge of the products, representing their inclination, at a portion with a constant slope of said gutter, and a signal representative of the excess or default deviation from a set height is formed, that the is applied to the adjustment of the speed of the upstream debtor apparatus, thereby correcting said inclination.

 In the device according to the invention for the implementation of the above method, the gutter has an upstream end disposed opposite the downstream end of a belt feed conveyor forming the upstream debtor device and an end downstream associated with a recovery conveyor forming the downstream receiving device, and two longitudinal flanges are mounted on either side of the constantly sloping part of the gutter and include a means of setting and adjusting the set height and a detector of the excess or default deviation of the upper edges of several consecutive products with respect to the set height, associated with corresponding excess and fault signal generators which are respectively connected to the speed control circuit a motor with adjustable speed driving the feed conveyor.

 In an embodiment reduced to its fundamental elements, the detector is constituted by optical sensors mounted on the flanges, respectively above, below and optionally at the set height, which form the signal generators, l 'all the sensors being adjustable in height relative to the gutter.

Preferably, however, the detector is constituted by a feeler comprising a shoe arranged longitudinally flat above the gutter and articulated by its center on the end of an inclined arm mounted on a first pivot axis transverse to the flanges and rendered secured to one end of a toothed sector, the other end of which is engaged with a toothed wheel. which is mounted on a second pivot axis transverse to the flanges and on which is fixed by its center a longitudinal bar whose two ends cooperate respectively with two optical or magnetic sensors which are mounted on a support associated with the flanges in an adjustable manner and form the signal generators, the arm being adjustable in inclination relative to the toothed sector.

 The signal generators are connected to the variable speed motor via a time delay element and are also connected to a constant speed booster motor with two directions of rotation, the adjustable speed motor shaft and that of the booster motor being respectively connected to the two inputs of a differential pulley whose output is connected to a drive member of the supply conveyor. According to a possible variant, the signal generators are connected to a production circuit of a constant voltage and are also connected, via a timing element, to a circuit for producing pulses of voltage successively increasing by positive or negative values, said circuits being connected to the speed control circuit of the adjustable speed drive motor of the feed conveyor.

 In the case where the device according to the invention is intended for the simultaneous regulation of several rows of products each delivered by a separate feed conveyor, a detector, a differential pulley and a booster motor are associated with each conveyor power supply, a single motor with adjustable speed being connected to all the differential pulleys and being connected to all the detectors via a timing element and an electronic calculation unit.

Other characteristics and advantages of the present invention will emerge more clearly from the description which follows, given with reference to the appended drawings in which
Figure 1 shows a schematic side view with partial cutaway of a preferred embodiment of a feeler device illustrating the method according to the invention
Figure-R-2 shows an exploded schematic perspective view of the device shown in Figure 1
Figures 3, 4 and 5 show schematic side views of the device visible in Figures 1 and 2, respectively corresponding to excess power, correct and insufficient; and
FIG. 6 represents a block diagram of a possible embodiment of the speed adjustment of the upstream conveyor.

 In these drawings, the same references designate the same elements.

 Referring to Figures 1 to 6, the process of automatic regulation of the transfer in line of products 1, which are parallelepiped and substantially identical, as indicated above, is of the type in which the products are supplied on edge with constant packing and a speed adjustable by an upstream debtor device, such as a belt feed conveyor 2, and are taken up with a constant pitch by a downstream receiving apparatus designated as a whole by 3. According to the invention, the products 1 from the upstream device 2 are slid into a gutter 4 along a downward path towards the downstream device 3, whereby said products tilt by gravity. At a portion 5 with a constant slope of the gutter 4, the height h is then measured between the bottom 6 of the gutter and the upper edge 7 of the products 1, this height representing the inclination of said products, and the a signal representative of the excess deviation e (FIG. 3) or by default d (FIG. 5) relative to a set height c (FIG. 4) is formed, which is applied to the adjustment of the speed of the upstream debtor device 2 for correcting said tilt, as will be explained in more detail below.

 In the device for implementing the method according to the invention, the gutter 4 has an upstream end 8, optionally provided with a connection plate 9 and disposed opposite the active strand of the downstream end 10 of the conveyor supply 2 forming the upstream debiting device, and a downstream end 11 which is associated with a recovery conveyor forming the downstream receiving device 3. In general, the gutter 4 has in cross section the shape of a U whose the dimensions obviously depend on the products to be transferred. In the case where the products 1 are cookies, the gutter 4 is preferably constituted by stainless steel, its bottom 6 being able to be formed by two parallel rods 12 and its side walls by two flat sections 13.

 The products 1 are continuously pushed along the gutter 4 by the following products which are brought with constant compaction by the feed conveyor 2. Under these conditions, the slope of the gutter 4 is produced so that the friction of the lower edge of the products 1 against the bottom 6 of the gutter causes the latter to take an inclined position under the effect of their own weight.

 According to an essential feature of the device according to the invention, two longitudinal flanges 14 and 15 are mounted on either side of the portion with a constant slope 5 of the gutter 4 and include a means of establishing and adjusting the height of setpoint c and a detector 16 of the deviation by excess e or by default d of the upper edges 7 of several consecutive products 1 relative to the setpoint height c. The detector 16 is associated with generators 17, 18 of corresponding excess and fault signals, which are respectively applied to the speed control circuit of a motor with adjustable speed driving the power conveyor 2.

 According to a simplified embodiment, which is given only by way of example, the detector 16 is constituted by optical sensors known per se and not shown in detail, which are mounted on the flanges 14 and 15, respectively above, below and possibly at the setpoint height c. In this embodiment, the optical sensors form the aforementioned signal generators 17 and 18. In addition, all of these sensors are adjustable in height relative to the gutter 4, thus constituting the means for establishing and adjusting the target height c.

 According to a preferred embodiment, the detector 16 is constituted by a feeler comprising a shoe 19 disposed longitudinally flat above the gutter 4 and articulated by its center 20 on the end of an inclined longitudinal arm 21 which is pivotable and optionally provided with an adjustable counterweight 22. The arm 21 is mounted on a first pivot axis 23 transverse to the flanges 14 and 15 and is made integral with one end 24 of a toothed sector 25 whose other end 26 is engaged with a toothed wheel 27 which is mounted on a second pivot axis 28 transverse to the flanges 14 and 15. A longitudinal bar 29 is fixed by its middle 30 on the toothed wheel 27 and its two ends 31 and 32 cooperate respectively with two sensors which are mounted on a support 33 associated with the flanges 14 and 15 and form the aforementioned signal generators 17 and 18.

 Preferably, all the moving parts of the probe are made of a light metal and the two pivot axes 23 and 28 are mounted on pivots 34 fixed in the flanges 14 and 15 and provided in known manner with adjustment screws 35. end 24 of the toothed sector 25 can be fixed on the first pivot axis 23, for example by means of a pin 36, while the arm 21 can be wedged on this axis by means of a simple pressure screw 37, such that the arm 21 is adjustable in inclination relative to the toothed sector 25, thus constituting the aforementioned means for establishing and adjusting the set height c, the flanges 14 and 15 can also be adjustable in height.

 For example, the two sensors forming the signal generators 17 and 18 can be optical sensors, in which case the two ends of the bar 29 are simple shutters intended to intercept the two light beams in a known manner. The two sensors or signal generators 17 and 18 can also be magnetic sensors, the bar 29 then consisting of soft iron. In both cases, the bar 29 cooperates with the sensors without any material contact, which makes it possible to lighten the entire moving equipment of the probe. Furthermore, the support 33 of the sensors or signal generators 17 and 18 is preferably pivotally mounted on the same axis 28 as the bar 29, thus making it possible to adjust the height of said sensors differently by means of a screw 38.

 When using the device according to the invention as described above, a set inclination is established for the products 1 sliding at the level of the constant slope portion 5 of the gutter 4, as a function of the settlement and the speed of the products supplied by the feed conveyor 2 forming the upstream debtor apparatus, the weight and the coefficient of friction of the products on the bottom 6 of said portion at constant slope and the flow of products taken up by the downstream receiver apparatus 3 The set height c is established (FIG. 4) by measuring the height h between the bottom 6 of the gutter 4 and the upper edge 7 of the products 1 for the set tilt and by positioning the arm 21 on the axis. 23 while the bar 29 is kept in the correct position relative to the signal generators 17 and 18.

 Under these conditions and with reference to FIG. 3, when the products 1 pass at the level of the detector 16 with an insufficient inclination and their height presents a deviation by excess e from the set height c, the lifting of the shoe 19 rotates the toothed sector 25 and, consequently, the toothed wheel 27 causes the bar 29 to cooperate with the generator 17 which provides a signal representative of said excess deviation to the speed control circuit of the motor with adjustable drive speed of the feed conveyor 2, so as to reduce the speed of the latter until the shoe 19 returns to a position for which the bar 29 no longer cooperates with the signal generator 17. Conversely, with reference to the figure 5, when the products 1 pass at the level of the detector 16 with an excessive inclination and their height exhibits a default deviation d with respect to the set height c, the lowering of the pad 19 makes the sector turn r toothed 25 and, therefore, the toothed wheel 27 causes the bar 29 to cooperate with the generator 18 which provides a signal representative of said default deviation when adjusting the speed of the feed conveyor 2, so as to increase the speed of the last.

 It should however be noted that the excess or default deviation signals may not be applied directly to the speed control circuit of an adjustable speed motor driving the supply conveyor 2, in particular in order to avoid that an accidental or short-term fault does not modify the speed of the said transporter. For this purpose, it suffices to interpose a time delay element between the signal generators 17, 18 and the speed control circuit of the drive motor.

 Furthermore, according to another possible embodiment and with reference to FIG. 6, the signal generators 17 and 18 are connected, via a timer element 39, to the speed control circuit of a adjustable speed motor 40 and are also connected to a booster motor 41 at constant speed and two directions of rotation. The shaft 42 of the variable speed motor 40 and the shaft 43 of the booster motor 41 are respectively connected to the two inputs of a differential pulley 44 whose output 45 is connected to a member 46 for driving the conveyor supply 2. Under these conditions, any excess or default deviation signal is applied to the booster motor 41 and immediately modifies the speed of the supply conveyor 2 while energizing the timing element 39. In the case of 'an accidental tilt defect, the shoe 19 quickly returns to its position corresponding to the set height c and interrupts the operation of the booster motor 41 while returning the timing element 39 to its rest position. On the other hand, in the case where the tilt defect is prolonged despite the speed change due to the auxiliary motor 41, the delay element 39 in turn transmits a signal to the control circuit of the main motor 40, the speed gradually increases or decreases, thus varying the speed of the feed conveyor 2 until the shoe 19 returns to the set position for which it stops the booster motor 41 and returns the timing element to its position rest, thus interrupting any variation in the speed of the main motor 40. It should be noted that stopping the auxiliary motor 41 results in a modification of the speed of the feed conveyor 2 which takes place in the opposite direction compared to the previous request. Consequently, the change in speed made by the booster motor 41 must be relatively small and is generally chosen so as to be slightly less than a range or zone of set heights, within the limits of which the displacements of the shoe 19. do not cause the generation of signals by generators 17 and 18.

 However, the embodiment described above is particularly desirable in the case where the device according to the invention is intended for the simultaneous regulation of several rows of products each delivered by a separate feed conveyor. Indeed, a detector 16, a differential pulley 44 and a booster motor 41 are then associated with each feed conveyor 2, while a single motor with adjustable speed 40 is connected to all the differential pulleys 44 and is connected to all the detectors 16 by means of a timer element 39 and an electronic calculation unit (not shown). It is obvious that the target speed of the single main motor 40 can thus be modified by a predetermined majority of excess or fault signals.

 In the embodiments described above, the main motor 40 and the booster motor or motors 41 can be alternating current or direct current motors. However, it is also possible to use only a main direct current motor and booster motor or differential pulley. For example, the signal generators 17 and 18 can be connected to a circuit (not shown) for producing a constant voltage and can also be connected, via a timer element such as element 39, to a circuit (not shown) for producing pulses of voltage successively increasing by positive or negative values, said circuits being connected to the speed control circuit of the motor with adjustable speed driving the power conveyor.

 Furthermore, by referring again to FIG. 1, it should be pointed out that, in the case where the recovery conveyor forming the downstream receiving device 3 is intended to take the products 1 flat, it may be constituted by a conveyor 47 of the chain type with cleats. In this case, the gutter 4 can be extended by a chute 48 rounded downwards, provided with an upper guide 49 and connected to a well 50 opening above the conveyor 47.

 It is understood that the present invention has only been described and shown for explanatory purposes, but is in no way limitative and that any useful modification may be made to it, in particular in the field of technical equivalences, without going beyond its ambit.

Claims (8)

 1. Method for automatic regulation of the transfer in line of substantially identical parallelepiped products between an upstream debtor device supplying the products on edge with constant settlement and an adjustable speed and a downstream receiver device taking them up with a constant pitch, characterized by the fact that the products from the upstream device are slid into a gutter along a downward path towards the downstream device, whereby said products tilt by gravity, the height is measured between the bottom of the gutter and the 'upper edge of the products, representing their inclination, at a part with a constant slope of said gutter, and a signal representative of the excess or default deviation from a set height is formed, that l 'is applied to the speed setting of the upstream debtor app-areil, thus correcting said inclination and, therefore, the power of the receiving device ava  2. Device for implementing the method according to claim 1, characterized in that the gutter has an upstream end disposed opposite the downstream end of a belt feed conveyor forming the upstream debtor device and a downstream end associated with a return conveyor forming the downstream receiving device, and that two longitudinal flanges are mounted on either side of the constant-slope part of the gutter and include a means of establishing and adjusting the target height and a detector of the excess or default deviation of the upper edges of several consecutive products with respect to the target height, associated with corresponding excess and fault signal generators which are respectively connected to the circuit for controlling the speed of a motor with adjustable speed driving the power conveyor  3. Device according to claim 2, characterized in that the detector is constituted by optical sensors mounted on the flanges, respectively above, below t possibly at the level of the set height, and forming the generators of signals, all the sensors being adjustable in height relative to the gutter.  4. Device according to claim 2, characterized in that the detector is constituted by a feeler comprising a shoe arranged longitudinally flat above the gutter and articulated by its middle on the end of an inclined arm mounted on a first pivot axis transverse to the flanges and secured to one end of a toothed sector the other end of which is engaged with a toothed wheel which is mounted on a second pivot axis transverse to the flanges and to which is fixed by its middle a longitudinal bar, the two ends of which cooperate respectively with two optical or magnetic sensors which are mounted on a support associated with the flanges in an adjustable manner and form the signal generators, the arm being adjustable in inclination relative to the toothed sector.  5. Device according to any one of claims 2 to 4, characterized in that the signal generators are connected to the speed-adjustable motor via a timing element and are also connected to a booster motor at constant speed and with two directions of rotation, the motor shaft with adjustable speed and that of the booster motor being respectively connected to the two inputs of a differential pulley whose output is connected to a drive member of the conveyor d 'food.  6. Device according to any one of claims 2 to 4, characterized in that the signal generators are connected to a circuit for producing a constant voltage and are also connected, by means of a timer element , to a circuit for producing pulses of voltage successively increasing by positive or negative values, said circuits being connected to the speed control circuit of the motor with adjustable speed driving the power conveyor.  7. Device according to claim 5, intended for the simultaneous regulation of several rows of products each delivered by a separate feed conveyor, characterized in that a detector, a differential pulley and a booster motor are associated with each feed conveyor, a single motor with adjustable speed being connected to all the differential pulleys and being connected to all the detectors by means of a timing element and an electronic calculation unit.  8. Device according to any one of claims 2 to 7, characterized in that the downstream conveyor is intended to take up the products flat and is preferably of the chain type with cleats, the gutter being extended by a trough rounded towards the bottom and connected to a well opening above said recovery conveyor.