US20080122167A1

US20080122167A1 - Unknown

Info

Publication number: US20080122167A1
Application number: US11/745,659
Authority: US
Inventors: Klaus Peter Paulat
Original assignee: BDT AG
Current assignee: BDT AG
Priority date: 2006-05-08
Filing date: 2007-05-08
Publication date: 2008-05-29
Also published as: DE202006007412U1

Abstract

The invention relates to a switch (5, 105) for signaling a position of a sheet (27) of paper, film or similar flat material in a transport path (3, 103), of a handling system (1), in particular of a feed system, for sheets (27) of paper, film or similar flat material, having an actuating mechanism (9) and a sensor (11, 111). In this case, according to the invention, a first actuating mechanism (9) has a lever (31) a toothed transmission (33) and an actuating element (21, 21′), which interacts with the optosensor (11), with the lever (31) having a stop (41) at one end for the sheet (27) and having a toothed profile (43) at the other end, which acts on the toothed transmission (33), in which case the actuating element (21, 21′) can be moved by the toothed transmission (33). Additionally or alternatively, a second actuating mechanism (109) has a wheel pair and an actuating wheel (128) which interacts with the sensor (111), with the wheel pair having a contact wheel (106) and a probe wheel (108) which roll on one another and between which the sheet (27) can be held, and which furthermore can be caused to rotate, and the rotation can be transmitted to the actuating wheel (128), which interacts with the probe wheel (108).

Description

The invention relates to a switch for signaling a position of a sheet of paper, film or similar flat material in a transport path of a handling system for sheets of paper, film or of a similar flat material, having at least one actuating mechanism and a sensor. The invention also relates to a handling system for sheets of paper, film or similar flat material, having a transport path for sheets of paper, film or similar flat material.
Systems for handling flat materials in the form of a sheet, for example a sheet of paper or a film, in particular a separation system, conveying system, feed system or storage system for sheets of paper, films or similar flat materials, are designed, in some cases, for precise handling of a sheet such that the handling system knows the position of a sheet during the handling process, for example the position of a sheet in a transport path.
For this purpose, it is known for two-armed integral levers to be provided, as described by way of example in DE 697 05 012 T2, DE 697 13 242 T2 or U.S. Pat. No. 6,409,043, such that a sheet strikes one lever arm, and the other lever arm interacts with a sensor.
A switch for signaling a position of the sheet of the type mentioned initially, that is to say a transport path switch with an actuating mechanism and sensor, is known from DE 196 10 978 A1. This document describes a paper identification apparatus which has a main lever and an auxiliary lever, which is fitted to the main lever such that it can pivot and has a free end which projects into the path of a sheet transport system. The main lever comprises a weight and a light-shielding plate with a window which is offset from the optical path of a paper identification sensor, when the auxiliary lever is operating, in order to block light incidence into a light receiving element.
As the requirements for handling speed become more stringent, the need to indicate the position of a sheet quickly as well as safely and precisely at the same time is also increasing. Already known switches for signaling a position need improvement for this purpose.
A switch will be desirable which satisfies the increasingly more stringent requirements for handling speed and accuracy.
This is the purpose of the invention, whose object is to specify a switch, in particular a transport path switch, and a handling system, in which the position of a sheet, of a piece of paper, of a film or similar flat material can be signaled quickly and precisely.
With regard to the switch, the object is achieved by the invention by means of a switch of the type mentioned initially, in which, according to the invention, a first actuating mechanism has a lever, a toothed transmission and an actuating element, which interacts with the sensor, with the lever having a stop at one end for the sheet and having a toothed profile at the other end, which acts on the toothed transmission, in which case the actuating element can be moved by the toothed transmission, and/or a second actuating mechanism has a wheel pair and an actuating wheel which interacts with the sensor, with the wheel pair having a contact wheel and a probe wheel which roll on one another and between which the sheet can be held, and which furthermore can be caused to rotate, and the rotation can be transmitted to the actuating wheel, which interacts with the probe wheel.
The invention is based on the idea that the combination of an actuating mechanism and a sensor, in particular an optosensor or magnetic sensor, is particularly advantageous to the design of the switch. Against this background, the invention has identified the fact that, according to the first variant, a lever can particularly precisely register a sheet being moved against the stop, by means of a stop that is formed at one end. The deflection of the lever that this results in at the same time results in an actuating element being moved via the toothed transmission and a tooth profile that is fitted at the other end of the lever. This results in the deflection of the lever produced by the sheet being converted virtually directly and instantaneously to a movement of the actuating element. Any movement or deflection of the actuating element is registered by the optosensor without delay and with optical precision, and can particularly precisely pass on the signaling of the position of the sheet.
On the basis of this concept of the invention, it has been found that the position of a sheet can be registered quickly and reliably with high sensitivity. This is because the deflection of the lever which is moved by the sheet itself according to the first variant, or of the wheel pair according to the second variant is converted directly to a movement of the actuating element or of the actuating wheel, and is perceived precisely by the sensor. Furthermore, it has been found that the switch operates particularly reliably, even when a sheet is moving at high speed. This means that, according to the concept of the invention, the switch is also particularly highly suitable for handling large numbers of sheets which follow one another quickly, be these paper, film or some other flat material, for example for a printer, copying or scanning system. According to the concept of the invention, this is due, in particular, to the fact that the actuating mechanism can be produced to be comparatively light in weight, so that the actuating mechanism mass to be moved and thus the inertia of the overall system is low in comparison to conventional known switches. According to the invention, the mass distribution in the actuating mechanism is also advantageously designed, specifically in the form of the lever which has the stop at one end and the toothed profile at the other end, and/or of the wheel pair which interacts with the actuating wheel via the probe wheel.
In addition, the second variant of the invention offers the advantage that the wheel system of the actuating mechanism and the actuating wheel allows the rotation angle of the probe wheel to be converted in a particularly preferred manner to a length unit—thus, depending on the embodiment of the probe wheel and of the actuating wheel, resulting in a particularly precise distance measurement device which is able to indicate the distance between the start and the end of a sheet, or the distance traveled by the sheet precisely by means of the position and the movement of a sheet.
In principle, the expression transport path means any free space which is intended for transportation of a sheet.
It has been found that the switch according to the concept of the invention is particularly advantageously suitable for a sheet, in particular a sheet of paper, which has a mass of more than 40 g/m². In particular, this may be a sheet of glossy paper, as is used by way of example in the field of photography or color printing, in particular for printing with ink or substances similar to ink. The individual parts of the switch, in particular the actuating mechanism, such as the lever, actuating element, toothed transmission wheel system, actuating wheel, advantageously have a total mass in the region of less than 0.4 grams.
Advantageous developments of the invention can be found in the dependent claims and indicate in detail advantageous possible ways to implement the concept explained above for the purposes of the object, as well as further advantages.
According to one particularly preferred development of the first variant of the invention, the toothed transmission is formed by means of a single gearwheel or a plurality of gearwheels, and the actuating element can be caused to rotate by a gearwheel. The toothed transmission advantageously comprises just one gearwheel, in particular with the toothed profile engaging with the gearwheel. The mass of the entire system is in this way advantageously kept low, thus in turn allowing particularly fast, hysteresis-free and thus direct and precise signaling of the position of a sheet of flat material.
In a further preferred development of the first variant of the invention, the toothed transmission is formed by means of a preferably single toothed rack, and the actuating element can be moved by the toothed rack. In this variant, and in contrast to the above-mentioned variant, the movement of the actuating element is more translational than rotary. The toothed profile engages with the toothed rack in a corresponding manner. The advantages as mentioned above in terms of speed and reduced hysteresis are achieved in an analogous manner in this variant of the invention.
According to one particularly preferred development of the first variant, the actuating element is attached to the toothed transmission, in particular to a gearwheel according to the first variant of the invention or to a toothed rack according to the second variant of the invention, preferably by being integrally formed thereon. In other words, deflection of the toothed transmission also results in an integral movement of the actuating element which, via the interaction with the optosensor, leads to signaling. The mass and the play of the actuating mechanism are improved in terms of reaction speed and freedom from hysteresis. According to this and the above-mentioned development of the invention, this ensures that the deflection of the lever is transmitted to the sensor particularly effectively and directly.
The transmitter in the form of an optosensor expediently has a transmitter and a receiver. It has been found to be particularly advantageous for the transmitter and the receiver to be fitted opposite one another in a fork holder.
The actuating element preferably acts as an interrupter between the transmitter and the receiver of the optosensor. In other words, the optosensor can be triggered on movement of the actuating element, or on movement of the actuating element away, by means of a movement as explained above. It is particularly advantageous for the actuating element to project into an optosensor fork holder, which has been found to be particularly suitable for this purpose.
In principle, the optosensor may be formed in any desired expedient manner, for example also by means of a motion sensor. It is expedient for the optosensor to be in the form of a light barrier. It has been found that a switch according to this development particularly advantageously achieves the object mentioned above, and can at the same time be produced particularly cost-effectively in this case.
In principle, an actuating element may be provided in a wide range of different forms. An actuating element in the form of a lug, a pin or a perforated plate has been found to be particularly advantageous. For example, a lug or a pin can be moved, or can be entirely moved out of the way, by means of the movement, as explained above, of the toothed transmission between a transmitter and a receiver of the optosensor. Triggering of the optosensor in this way directly signals the position of the sheet of flat material. The distance to triggering of the optosensor can advantageously be reduced by the lug or the pin being formed with particularly small dimensions. Equally, the design should ensure that very small movements of the actuating element do not in their own right lead to triggering of the optosensor, that is to say the dimensions should also not be excessively small. This aspect can be taken into account particularly expediently by an actuating element in the form of a perforated plate. The size of a hole on the one hand influences the rate of reaction and sensitivity of the switch, but the hole should not be smaller than a specific size, since the switch would otherwise trigger the signaling in the noise area or in response to random deflections of the actuating element.
In order to further reduce the mass of the actuating mechanism, one tooth of the toothed transmission or an extension of a tooth of the toothed transmission can also form the actuating element. This has the advantage that there is no need to separately fit an actuating element to the toothed transmission, since a part of the toothed transmission itself—in the present case in the form of a tooth or of an extension of the tooth—represents the actuating element for triggering of the optosensor.
According to one development, the sensor may also be in the form of a magnetic sensor. This has been found to be particularly advantageous for the purposes of one development of the second variant of the invention. Rotation of the wheel system can preferably be converted to a magnetic rotating field, which can be detected and converted to a length unit via a magnetic sensor. By way of example, the magnetic sensor may be in the form of an induction sensor, or may be formed in some other suitable manner, for example in the form of a Hall sensor or the like for detection of a magnetic field.
For the purposes of one development of the second variant of the invention, the pressure wheel and the probe wheel can preferably be moved away from one another against an opposing force, in particular in the form of a spring force, in order to hold the sheet. The sheet can thus be held clamped between the pressure wheel and the probe wheel while being passed through between them, while the probe wheel runs on the surface of the sheet and in this way makes it possible to particularly precisely measure the distance traveled by the sheet.
A particularly precise measurement can be achieved by the actuating wheel being in the form of a clock wheel with a number of slots at equal intervals. Appropriate precise angular accuracy can be achieved depending on the distance between the slots. In particular, the slots are used for clocking an optosensor.
Alternatively or additionally, the actuating wheel may be designed to produce a magnetic rotating field, in particular for clocking a magnetic sensor, such as a Hall sensor. For this purpose, for example, the actuating wheel may be provided with an arrangement of individual magnets splitting the angle.
One fairly particularly preferred development of the second variant of the invention provides for the capability to convert the rotation angle of the probe wheel to a length unit by means of a submillimeter marking which is fitted to the probe wheel and the sensor. For example, the probe wheel may be in the form of a knurled wheel on its circumferential outer face facing the sheet. It has been found to be particularly preferable for the probe wheel to be in the form of a steel disk with laser-machined grooves on the circumferential outer face facing the sheet. The knurling or grooves not only make it possible for the probe wheel to roll on the sheet without sliding but, depending on the distance between the individual grooves or knurling markings—for example in the region of 0.2 mm or 0.1 mm—offer position accuracy for detection of a movement distance on the sheet surface down to the region of hundredths of a millimeter.
The probe wheel and the actuating wheel according to the second variant of the invention are preferably arranged such that they interact by means of at least one step-up transmission wheel.
A further development according to the second variant of the invention provides for the capability for the wheel pair, possibly together with the actuating wheel, to be tilted, in particular to be tilted relative to the transport path. This means that—even if a sheet is introduced at an angle in the rolling area of the pressure wheel and probe wheel—the entire arrangement can be adjusted freely to the introduction angle of the sheet, therefore nevertheless allowing movement distance measurement that is not corrupted by the introduction angle.
Overall, the developments mentioned above according to the second variant of the invention lead to a particularly precise distance measurement device for the purposes of a switch for signaling a position of the one, that is to say in addition to or as an alternative to a first actuating mechanism.
One particularly preferred development of the switch occupies a space which does not exceed the dimensions of 23 mm×23 mm×30 mm, and preferably does not exceed the dimensions 20 mm×20 mm×20 mm. The smaller the switch is, the less is the inert mass of the actuating mechanism to be moved, so that a reduction in the size of the switch advantageously makes it possible to improve the speed and freedom from hysteresis of the actuating mechanism.
The actuating mechanism is expediently formed substantially from a plastic material. This has been found to be particularly robust, while reducing the weight at the same time. It has been found that the plastic material also always ensures safe switching, even in a humid environment.
In order to move the actuating mechanism back after being deflected by a sheet, this mechanism preferably has a return means, in particular in the form of a spring. In the case of the first variant, a spring can preferably be fitted between the lever and a holder for the actuating mechanism. In other words, when a sheet strikes the lever stop, this is deflected against the force of the return means, and is subsequently moved back again, by this force. The stop may preferably have an element which can rotate and is arranged at the end, preferably in the form of a roll. This has the advantage that, when a sheet is passing through it, this very largely prevents any adverse effect on the upper face of the sheet. Rolling friction has been found to be better than sliding friction. According to one preferred development of the second variant, a return means, in particular a spring, is fitted between the pressure wheel and the holder, and/or between the probe wheel and the holder for the actuating mechanism.
According to the first variant, the lever arm which forms the stop preferably has two limbs. A sheet then strikes against two limbs of the lever, which are expediently arranged on both sides of a bearing, which is then uniformly loaded. This avoids tilting problems, or loosening of the bearing.
For the purposes of one particularly preferred development of the first variant, the stop projects substantially at right angles into the transport path. This has the advantage that the switch can be triggered symmetrically from both sides via a transport path running transversely with respect to the lever arm. This advantageously ensures symmetrical switching hysteresis. Furthermore, positioning at right angles to the transport path has the advantage that the lever is returned to its position independently of operation. According to the second variant, the wheel pair, in particular in the rolling area for holding the sheet, projects as right angles into the transport path.
For the purposes of a further particularly preferred development of the invention, the transport path has a constriction in the area of the stop. This results in virtually funnel-shaped guidance of the sheet in the direction of the lever stop, irrespective of the side. The risk of tilting of the sheet in the transport path is avoided, and the positioning accuracy of the switch is increased. This advantageously improves safe and precise switching even at high sheet feed rates.
A constriction is preferably formed by a rib or roller arranged in the transport path. It has been found particularly advantageous to arrange a rib on both sides of the stop, that is to say in the form of a pair of ribs. In the region of the constriction, the transport path has a height of at least 1.75 mm, so that a paper thickness of up to 1.25 mm can advantageously be handled.
The sensor, in particular the optosensor or a magnetic sensor, preferably has an electrical connection for electronic relaying of the signaling. In particular, the connection is arranged on one face and/or on one end face of a holder for the sensor. In particular, this has design advantages.
In order to achieve the object, the invention also has a handling system, in particular a separation or conveying system, for example a feed system for paper, film or similar flat material, having a transport path for paper, film or similar flat material. According to the invention, the handling system has a switch according to the concept as explained above or according to one of the developments. Furthermore, the concept of the invention has also been found to be advantageously applicable to a storage system. In particular, this relates to so-called finishers, which are used to store sheets or to handle them after printing.
While the invention has been found to be particularly useful for usage relating to handling systems, it should be understood in a general form in this context, and although the invention will be explained in detail in the following text on the basis of examples relating to a handling system in the form of a feed system for paper, film or a similar flat material, it should nevertheless be clear that the concept described here, as claimed, is likewise useful for the purpose of other applications which are not described in this document. The proposed concept has been found to be particularly advantageous for use with printers, scanners, copiers and other copying systems, in particular those systems which are increasingly being required for fast paper handling.
Exemplary embodiments of the invention will now be described in the following text with reference to the drawing. This drawing is not intended to illustrate the exemplary embodiments to scale, but in fact, when used for explanatory purposes, is in a schematic and/or slightly distorted form. With regard to supplements to the teaching that can be seen directly from the drawing, reference is made to the relevant prior art.
In this case, it should be noted that the form and details of the embodiment may be modified and changed in many ways without departing from the general idea of the invention. The features of the invention disclosed in the present description, in the drawing and in the claims may be significant developments of the invention both individually and in any desired combination. The general idea of the invention is not restricted to the exact form or the detail of the embodiment shown and described in the following text, and is not restricted to a subject matter which would be restricted in comparison to the subject matter claimed in the claims. Where dimension ranges are quoted, values lying within the stated limits are also intended to be disclosed as limit values and can be used and claimed as required.

For further understanding of the invention, one preferred embodiment of the invention will now be explained with reference to the figures in the drawing, based on the example of a bidirectional precision switch for signaling a position of a sheet of paper in a paper feed system. In the drawing:

FIG. 1 shows a perspective three-dimensional illustration of one preferred embodiment of a detail of a handling system having a bidirectional, precise transport path switch for a transport path according to the first variant of the invention;

FIG. 2 shows a side view of one preferred embodiment of a bidirectional, precise transport path switch for a transport path according to FIG. 1, before activation;

FIG. 3 shows the embodiment of a transport path switch as shown in FIGS. 1 and 2, in the state in which it has been activated on the right-hand side by a sheet being moved toward it from the right-hand side;

FIG. 4 shows the embodiment of a transport path switch as shown in FIGS. 1 and 2 in the state in which it has been activated from the left-hand side, by a sheet being moved toward it from the left-hand side;

FIG. 5 shows a perspective illustration from underneath the embodiment shown in FIG. 1, from a perspective in the transport path;

FIG. 6 shows a plan view of the embodiment shown in FIG. 1;

FIG. 7 shows a section view of one preferred embodiment of a detail of a handling system having a precise distance measurement device for a transport path according to the second variant of the invention.

FIG. 1 shows a part of a handling system 1, in the present case as part of a paper feed system for a printer with a transport path 3 and a switch 5 as explained in more detail in the following figures. For this purpose, the switch 5 has an actuating mechanism 9, which is fitted to a holder 7, and an optosensor 11 which is arranged on a further holder 13. One connection 15A may advantageously be arranged on an end face of the further holder 13 for the optosensor 11. Alternatively or additionally, a connection 15B may be arranged on one face of the holder 13 of the optosensor 11. The connections 15A, 15B are used to pass on the signals supplied from the optosensor 11, and for activation of the optosensor 11. For this purpose, one connection 15A, 15B has a line 17A provided for a transmitter 11A, a line 17B provided for a receiver 11B for the optosensor 11, and a ground line 17C.
The optosensor 11 itself is fitted to a fork holder 19, and is in the form of a light barrier with said transmitter 11A and said receiver 11B. The transmitter 11A and the receiver 11B are fitted to different limbs of the fork holder 19 and are located opposite one another. An actuating element 21, which will be explained further below, for the actuating mechanism 9 projects into the intermediate space formed in this way.
On the basis of the principle of operation of the switch 1, as explained in more detail in FIGS. 2 to 4, a sheet of paper being carried in the transport path 3 triggers the actuating mechanism 9, which leads to a movement of the actuating element 21 that is registered by the optosensor 11, and thus to signaling of the position of the sheet of paper in the transport path 3, via the connections 15A, 15B.
FIG. 2 shows a side view of the switch 5, which is mounted on a base plate 23 by means of the holder 7. The base plate is in turn arranged at a distance from a lower plate 25, but parallel to it, in a suitable manner. A transport path 3, which is designed for introduction of a sheet of paper 27, is formed between the base plate 23 and the lower plate 25. FIG. 2 and FIG. 3 illustrate the process of passing a sheet of paper 27 through from a direction 29A on the right-hand side. FIG. 4 shows the state of the switch 5 when the sheet of paper 27 is being passed through from a direction 29B on the left-hand side. The same reference symbols are used for the same features.
The actuating mechanism 9 of the switch 5 has a lever 31, a toothed transmission 33 and an actuating element 21. In the present case, the lever 31 is mounted such that it can rotate on a shaft 35 which passes through the holder 7, in the same way as that in which the single gearwheel, which forms the toothed transmission 33, is mounted such that it can rotate on a further shaft 37 passing through the holder. A flywheel mass 39, which has a semicircular shape in the present case, is firmly connected to the gearwheel 33 such that it can rotate, and its projection fitted to the circumference is in the form of the actuating element 21. In this case, the actuating element 27 projects in the manner explained with reference to FIG. 1 along the extent B into an intermediate space 20, which is shown in more detail in FIG. 6, between a transmitter 11A and a receiver 11B for the optosensor 11. The flywheel mass is designed on the basis of the movement inertia of the actuating mechanism 9.
In order to signal the position of the sheet of paper 27, the lever 31 has a stop 41 at one end for the sheet, and a toothed profile 43 at the other end, which acts on the toothed transmission 33 in the form of the gearwheel, with the toothed profile 43 engaging 34 with the gearwheel 33. In other words, the teeth 43′ of the toothed profile 43 engage in intermediate spaces between the teeth 33′ on the gearwheel 33, and vice versa.
When introduced from the direction 29A on the right-hand side as illustrated in FIG. 3, a butt edge 27A of the sheet of paper 27 moves against the stop 41 of the lever 31. In order to very largely prevent the sheet of paper 27 from being folded up by the impact force, and at the same time ensuring safe guidance of the sheet 27 in the area of the stop 41, the transport path 3 has a constriction 45 in the area of the stop 41. In the present case, the constriction 45 is formed by a rib 47 projecting from the base plate 23, and a further rib 49 projecting from the lower plate 25.
As can be seen from FIG. 5, the rib 47 is in the present case in the form of a pair of ribs, on both sides of the stop 41. The rib 49 which projects from the base plate 25 is advantageously in the form of a catch which extends transversely with respect to the transport path, preferably completely between the two ribs 47. In a modification of the present embodiment, the rib 49 may likewise be formed only in the area, preferably with respect to a rib 47, for example in the form of a pair of ribs. The constriction 45 formed in the transport path 3 ensures that the sheet 27 is fed precisely and safety to the stop 41 in the area of the stop 41, and deflects the lever 31 with the butt edge 27A in the manner shown in FIG. 2.
The lever 31 is deflected against the force of a return means 51, which is in the form of a spring. In the present case, the spring 51 is likewise deflected when the lever 31 is deflected, and is expediently designed for a shock force. The toothed profile 43, which engages 34 with the gearwheel 33, moves the gearwheel 33 in the rotation direction 53, via the deflection of the lever 31. In consequence, the actuating element 21 which is integrally formed on the flywheel mass 39 is moved out of the intermediate space between the transmitter 11A and the receiver 11B for the optosensor 11. This is designed for a switching point 55. In other words, the actuating element 21, which is used as an interrupter between the transmitter 11A and the receiver 11B for the optosensor 11, is now removed from the intermediate space, and in particular rotates beyond a line defined by the switching point 55. This triggers the optosensor 11—in the present case the light barrier 11 is closed and emits a signal via the connection 15A, 15B. This mechanical movement process leads, together with the triggering of the optosensor 11, to signaling the position of the sheet 27. In other words, as soon as the butt edge 27A strikes the stop 41 of the stop, the actuating element 21 starts to move out of the area between the transmitter 11A and the receiver 11B. As soon as the actuating element 21 has moved out completely, that is to say it has been rotated beyond the switching point 55, the optosensor 11 is triggered and signals the position of the sheet 27, as a consequence of this virtually without hysteresis and precisely. Specifically, the emission of an electrical signal from the optosensor 11 via the connection 15A, 15B is dependent on the butt edge 27A being located centrally at the same height as the position predetermined by the vertical alignment 36 of the stop 41, that is to say in a position which corresponds virtually to the narrowest point of the constriction 45.
According to a first embodiment, which is illustrated by way of example in FIGS. 1, 5 and 6, the stop 41 may be provided with a butt stop end, which is slightly rounded in the present embodiment, and passes over the surface of the sheet 27 as the sheet 27 passes through. In an alternative embodiment to this, as is shown by way of example in FIGS. 2, 3 and 4, the end of the stop 41 may be provided with a roller 36A, which is shown by dashed lines and is attached to the stop 41 such that it can rotate. This embodiment, which is shown by way of example, ensures that the end of the stop 41 in the form of the roller 36A, is guided such that it rolls over the surface of the sheet 27 as the sheet 27 passes through—very largely avoiding sliding friction. Furthermore, this may have the advantage that it avoids unnecessary grooves, caused by a sliding process, or other impressions on the surface of a sheet 27. Particularly where the sheet 27 is in the form of sensitive, for example thin, paper or glossy paper, this has been found to be advantageous since grooves or impressions can be seen particularly easily in this case.
The extent B of the actuating element 21 along the circumferential profile of the flywheel mass 39 ensures that the optosensor is not inadvertently triggered in the event of a slight movement of the gearwheel 33, which may be classified as noise. The sensitivity of the switch 5 can be further increased by reducing a width B, for example to a width B′, of the actuating element 21—that is to say an alternative actuating element 21′, although this worsens the risk of inadvertent triggering.
The adequately calculated extent B of the actuating element 21 has the advantage that the optosensor is not inadvertently activated again if the gearwheel 33 together with the flywheel mass 39 overshoots, particularly when being returned by the spring 51. The extent B of the actuating element 21 is to this extent a measure of the inertia of the mass system, which is formed substantially by the gearwheel 33, the flywheel mass 39 and the actuating element 21.
In the present case, the switch is designed to be comparatively light in weight. The dimensions of the switch 5 illustrated in perspective form in FIG. 1 lie within an area of 20 mm×20 mm×15 mm (L, W, H). The height h of the transport path 3 is at least 1.75 mm, in particular in the area of the constriction 45. The total weight of the actuating element 21 together with the flywheel mass 39 does not exceed 1.7 g. The weight of the lever is no more than 2.1 g. In this embodiment, the switch 5 is particularly suitable for signaling a position of paper whose weight is preferably more than 50 g/m².
As can be seen from FIG. 4, the movement process described with reference to FIG. 3 can also be carried out with a sheet of paper 27 inserted from the direction 29B on the left-hand side—virtually symmetrically with respect to the movement process as is shown in FIG. 3. This has the advantage that the lever 31 is deflected with virtually symmetrical hysteresis. This ensures not only that the position of the sheet 27 is signaled with little hysteresis, but also that the position is signaled with symmetrical hysteresis—that is to say irrespective of whether the sheet 27 is introduced into the transport path 3 from the direction 29B on the left-hand side or from the direction 29A on the right-hand side.
In particular, FIG. 5 shows the double-limbed embodiment of the stop 41. This prevents the sheet 27 from tilting against the stop 41 since, as is shown in FIG. 5, this is held along an imaginary line 42 from the left-hand to the right-hand limb of the stop 41.
FIG. 6 shows a view of the handling system as explained in FIG. 1, with a switch 5, with the same reference symbols being used for the same features.
FIG. 7 shows one particularly preferred embodiment of a switch 105 for signaling a position of a sheet 27, in the present case composed of paper, in a transport path 103 of a handling system 1 which is not illustrated in any more detail. In the present case and according to the second variant of the invention, the switch 105 has a second actuating mechanism 109 and a sensor 111, which in the present case is in the form of an optosensor. The actuating mechanism 109 is in the form of a pair of wheels with a pressure wheel 106 and a probe wheel 108, with the probe wheel and the pressure wheel rolling on one another in a rolling area 104. For this purpose, the pressure wheel 106 and the probe wheel 108 are each mounted on a shaft 112, which is held on a die 114 with one die 114 in each case being pressed by a spring 116 in the direction of the rolling area 104. When a sheet 27 is introduced, the pressure wheel 106 and the probe wheel 108 are thus forced apart from one another against the spring force of the spring 116 in the rolling area 104, and they respectively roll on an upper face and a lower face of the sheet 27. In order to allow the sheet 27 to be introduced particularly accurately, the transport path is formed in a similar manner to that in the case of the embodiment of the first actuating mechanism as explained above with a base plate 123 and a lower plate 125, which form a constriction 145 in the rolling area 104.
Furthermore, the entire wheel system arrangement of the switch 105 is mounted such that its axis 118 can be tilted through a certain tile angle 122. The pressure wheel 106 and the probe wheel 108 are set to the introduction angle within the range of the tilt angle 122 when a sheet 27 is introduced obliquely, thus allowing particularly precise detection of the start and of the end of the sheet 27. Furthermore, particularly precise distance measurement is achieved for the distance traveled by the sheet 27 by providing the probe wheel with knurling 124, which effectively governs the smallest step width of the probe wheel 108 on the circumferential outer face of the probe wheel 108 facing the sheet 27. In the present case, the probe wheel 108 is in the form of a laser-machined steel disk, which is provided with grooves, which form the knurling 124, at an interval of 0.2 mm. This means that the start and the end of the sheet 27 can be detected to an accuracy of 0.1 mm in the rolling area 104. Furthermore the knurling 124, which increases the friction, prevents any slip of the probe wheel 108 as it rolls on the sheet 27. Overall, the system which can be tilted in an oscillating manner about the axis 118, in conjunction with the very fine knurling 124 satisfies the precondition for distance measurement, of a precision which it has not been possible to achieve until now, with respect to the length of a sheet and the distance traveled by a sheet 27 in the rolling area 104. The distance, which corresponds to the circumferential rotation angle, is passed to the actuating wheel 128 via a step-up transmission wheel 126 which is fitted or coupled to the actuating wheel. The actuating wheel 128 is provided with a number of uniformly separated slots—46 in the present case—which—in the present case separated by about 0.2 mm and with a width of 0.1 mm—pass on a clock pulse, which corresponds to the rotation angle of the probe wheel 108 to the optosensor 111 via its sensor openings 130 during rotation of the actuating wheel 128, which clock pulses are converted by the sensor 111 to a circumferential distance traveled by the probe wheel 108 on the surface of the sheet 27, with this distance being indicated. The distance measurement accuracy achieved by the particularly accurate embodiment of the knurling 124 on the probe wheel 108 is thus converted by an appropriately matched design of the slot arrangement 120 on the actuating wheel 128 to a very precise rotation angle which can be indicated and corresponds to the distance traveled by the sheet 27.
The particularly preferred embodiment of a transport path switch 105 as shown in FIG. 7 also allows—on its own or in conjunction with the embodiment of a transport path switch as illustrated in FIG. 1 to FIG. 6—in addition to determination of the position of the sheet 27, accurate distance measurement, a precision which it has not been possible to achieve until now, for the distance traveled by the sheet 27 on the transport path 103.
In summary, a switch 5, 105 for signaling a position of a sheet 27 of paper, film or similar flat material in a transport path 3, 103 of a handling system 1, in particular of a feed system, for sheets 27 of paper, film or similar flat material, having an actuating mechanism 9 and a sensor 11, 111, is described. In this case, according to the invention, a first actuating mechanism 9 has a lever 31, a toothed transmission 33 and an actuating element 21, 21′ which interacts with the optosensor 11, with the lever 31 having a stop 41 at one end for the sheet 27 and a toothed profile 43 at the other end, which acts on the toothed transmission 33, in which case the actuating element 21, 21′ can be moved by the toothed transmission 33. Additionally or alternatively, a second actuating mechanism 109 has a pair of wheels and an actuating wheel 128 which interacts with the sensor 111, with the pair of wheels having a pressure wheel 106 and a probe wheel 108, which roll on one another, between which the sheet 27 can be held and furthermore can be caused to rotate, which rotation can be transmitted to the actuating wheel 128 which interacts with the probe wheel 108.

Claims

1. Switch (5, 105) for signaling a position of a sheet (27) of paper, film or similar flat material in a transport path (3, 103) of a handling system (1) for sheets (27) of paper, film or of a similar flat material, having at least one actuating mechanism (9) and a sensor (11, 111), characterized in that

a first actuating mechanism (9) has a lever (31), a toothed transmission (33) and an actuating element (21, 21′), which interacts with the sensor (11), with the lever (31) having a stop (41) at one end for the sheet (27) and having a toothed profile (43) at the other end, which acts on the toothed transmission (33), in which case the actuating element (21, 21′) can be moved by the toothed transmission (33), and/or a second actuating mechanism (109) has a wheel pair and an actuating wheel (128) which interacts with the sensor (111), with the wheel pair having a contact wheel (106) and a probe wheel (108) which roll on one another and between which the sheet (27) can be held, and which furthermore can be caused to rotate, and the rotation can be transmitted to the actuating wheel (128), which interacts with the probe wheel (108).

2. Switch (5) according to claim 1, characterized in that the toothed transmission (33) is formed by means of a single gearwheel, and the actuating element (21, 21′) can be caused to rotate by the gearwheel.

3. Switch (5) according to claim 1, characterized in that the toothed transmission (33) is formed by means of a single toothed rack, and the actuating element (21, 21′) can be moved by the toothed rack.

4. Switch (5) according to one of claims 1 to 3, characterized in that the toothed profile (43) engages with the toothed transmission (33).

5. Switch (5) according to one of claims 1 to 4, characterized in that the actuating element (21, 21′) is attached to the toothed transmission (33), in particular to a gearwheel or to a toothed rack of the toothed transmission (33).

6. Switch (5) according to one of claims 1 to 5, characterized in that the sensor is in the form of an optosensor (11), in particular having a transmitter (11A) and a receiver (11B) which, in particular, are fitted opposite one another in a fork holder.

7. Switch (5) according to one of claims 1 to 6, characterized in that the actuating element (21, 21′) acts as an interrupter between a transmitter (11A) and a receiver (11B) for the optosensor (11), in particular projecting into an intermediate space (20) when the optosensor (11) is in the form of a fork holder.

8. Switch (5) according to one of claims 1 to 7, characterized in that the optosensor (11) is in the form of a light barrier.

9. Switch (5) according to one of claims 1 to 8, characterized in that the actuating element (21, 21′) is in the form of a lug, a pin, a perforated plate or a tooth (33′) of the toothed transmission (33), or an extension of the tooth (33′) of the toothed transmission (33).

10. Switch (5, 105) according to one of claims 1 to 9, characterized in that the sensor (11) is in the form of a magnetic sensor.

11. Switch (105) according to one of claims 1 to 10, characterized in that the pressure wheel (106) and the probe wheel (108) can be moved away from one another against an opposing force, in particular a spring force, in order to hold the sheet (27).

12. Switch (105) according to one of claims 10 to 11, characterized in that the actuating wheel (128) is in the form of a clock wheel with a number of slots (120) at equal intervals, in particular for clocking an optosensor.

13. Switch (105) according to claims 1 to 12, characterized in that the actuating wheel (128) is designed to produce a magnetic rotating field, in particular for clocking a magnetic sensor.

14. Switch (105) according to one of claims 1 to 13, characterized in that the rotation angle of the probe wheel (108) can be converted to a length unit by means of a submillimeter marking, which is fitted to the probe wheel (108) and the sensor (111), in particular in order to signal the distance traveled by the sheet (27).

15. Switch (105) according to one of claims 1 to 14, characterized in that the probe wheel (108) is in the form of a knurled wheel, in particular a steel disk with laser-machined grooves.

16. Switch (105) according to one of claims 1 to 15, characterized in that the probe wheel (108) and the actuating wheel (128) interact by means of at least one step-up transmission wheel (126).

17. Switch (5, 105) according to one of claims 1 to 16, characterized by the space required not exceeding 23 mm×23 mm×30 mm, and preferably being 20 mm×20 mm×20 mm.

18. Switch (5, 105) according to one of claims 1 to 17, characterized in that the actuating mechanism (9) is substantially composed of a plastic material.

19. Switch (5, 105) according to one of claims 1 to 18, characterized in that the actuating mechanism (9, 109) has a return means (51, 116), in particular in the form of a spring, in particular a spring which is fitted between the lever (31) and a holder (7) for the actuating mechanism (9), or a contact wheel (106) and/or a probe wheel (108) of the wheel pair and the holder for the actuating mechanism (109).

20. Switch (5, 105) according to one of claims 1 to 19, characterized in that the stop (41) projects substantially at right angles into the transport path (3, 103), in particular in the form of a two-limbed lever arm (FIG. 5), and/or the wheel pair, in particular with the stop (41) having an element (36A) which can rotate and is arranged at the end.

21. Switch (5, 105) according to one of claims 1 to 20, characterized in that the transport path (3, 103) has a constriction (45) in the area of the stop (41), in particular the constriction which is formed by a rib (47, 49), in particular with a rib being arranged on both sides of the stop and/or wheel pair (FIG. 5).

22. Switch (5, 105) according to one of claims 1 to 21, characterized in that the transport path (3, 103) has a height of at least 1.75 mm.

23. Switch (5, 105) according to one of claims 1 to 22, characterized by a connection (15A, 15B) for electronic relaying of the signaling from the sensor (11, 111).

24. Switch (5, 105) according to one of claims 1 to 23, characterized in that a connection (15A, 15B) is arranged on one face and/or on one end face of a holder (13) for the sensor (11, 111).

25. Handling system (1), in particular a separation system, conveying system, feed system or storage system, for sheets (27) of paper, film or similar flat material, having a transport path (3, 103) for sheets (27) of paper, film or similar flat material, characterized by a switch (5, 105) according to one of claims 1 to 17.

26. Handling system (1) according to claim 25, in the form of a printer, copying or scanning system.