pressure device

Abstract

Pressure device for pressing adhesive labels against a substrate (14), comprising a pin slide plate (10) with several pressure pins (18) arranged parallel to each other in a row along an edge of the pin slide plate and which can be pushed back axially into the pin slide plate against a spring force, and comprising a control device (40) for controlling a pressure movement of the pin slide plate (10), characterized in that at least one of the pressure pins (18) has a touch sensor (42) which is configured to supply a touch signal to the control device (40).

Description

[0001] The invention relates to a pressure device for pressing adhesive labels against a substrate, comprising a pin slide plate with a plurality of pressure pins which are arranged parallel to one another in a row along an edge of the pin slide plate and can be pressed back axially into the pin slide plate against a spring force, and comprising a control device for controlling a pressure movement of the pin slide plate.

[0002] Pressure devices of this type are used, for example, in labeling machines to press the adhesive labels against packaging containers or other substrates. Typically, several pin-push plates are arranged parallel to each other in the spaces between the conveyor belts on which the adhesive labels are transported. When the adhesive labels are correctly positioned relative to the substrate, the pin-push plates jointly perform a stroke perpendicular to the transport plane of the adhesive labels, pressing the labels against the substrates. The spring-loaded pressure pins ensure an even distribution of the pressure force across the surface of the labels, even with uneven substrate surfaces.

[0003] Typically, the pin slide plates are pneumatically driven for the stroke movement. By throttling the pneumatic lines, a specific stroke speed of the pin slide plates is set, and the stroke is controlled by the length of the time interval between the start of the forward stroke and the switchover to the reverse stroke. The spring-loaded pressure pins allow a certain tolerance in the stroke adjustment.

[0004] In general, correctly adjusting the stroke travel is often difficult, as the stroke speed is subject to numerous interfering influences. Precise adjustment of the stroke travel is particularly important for pressure-sensitive substrates, as the contact force would exceed the permissible limits if the maximum spring travel of the pressure pins were exceeded.

[0005] The object of the invention is therefore to provide a pressure device in which the stroke of the pin slide plate can be precisely controlled.

[0006] This object is achieved according to the invention in that at least one of the pressure pins has a touch sensor which is designed to supply a touch signal to the control device.

[0007] In the device according to the invention, the reversal of the stroke direction of the pin slide plate can be triggered directly by the signal of the touch sensor, so that fluctuations in the stroke speed have no influence on the stroke path.

[0008] Advantageous embodiments of the invention are specified in the subclaims.

[0009] If at least two of the pressure pins have a touch sensor, correct control of the stroke is possible even if the surface of the substrates is not exactly parallel to the edge of the pin slider plate.

[0010] In an advantageous embodiment, all pressure pins of all pin-sliding plates have a touch sensor. By logically ANDing the touch signals, it is possible to ensure that the stroke direction is only reversed when all pressure pins touch the substrate.

[0011] The touch sensors can be designed in such a way that they only provide a touch signal when the pressure pin is compressed by a certain distance and thus exerts a predetermined minimum pressure force on the label and on the substrate.

[0012] In one embodiment, the compression movement of the pressure pins relative to the pin slide plate is used to provide the energy needed to generate the touch signal, for example, inductively or piezoelectrically. In this case, no electrical wires are required to supply power to the touch sensors.

[0013] The touch sensors of one or more pin slide plates can be connected to a transponder that wirelessly transmits the AND-linked touch signal to the control device.

[0014] The following is a detailed description of an embodiment using the drawings. They show: Fig. 1 a view of a pin slide plate and an associated pneumatic drive of a pressure device according to the invention; and Fig. 2 a section through a pressure pin and a part of the pin slide plate that receives it.

[0015] In Fig. 1 shows one of several pin slide plates 10, which can be driven to perform a lifting movement by a common pneumatic drive 12 and serve to press adhesive labels (not shown) against one or more substrates 14. The substrates 14 can be, for example, packaging containers produced by deep-drawing a film 16. By intermittently transporting the film 16, the substrates 14 can be brought into a position in which they can be labeled with the aid of the pressure device formed by the pin slide plates 10 and the drive 12. For feeding the adhesive labels, several synchronously drivable transport belts are provided, which run parallel to the pin slide plates in the spaces between the individual pin slide plates. For reasons of clarity, these transport belts are not shown here.

[0016] Each pin slide plate 10 has, along its edge facing the substrates 14, a row of pressure pins 18 which project parallel to one another from the edge of the pin slide plate and are guided in the pin slide plate for axial movement. As will be explained later with reference to Fig. As will be explained in more detail in Figure 2, each pressure pin 18 is elastically biased upwards, i.e., toward the substrates 14. Furthermore, each pressure pin has two stop pins 20, which are guided in guide slots 22 in the walls of the pin slide plates 10.

[0017] Fig. 1 shows the pressure device in a state in which the pin slide plate 10 is extended against the substrates 14, so that the pressure pins 18, which contact the substrate 14, spring back slightly and thus exert a certain pressure force on the label and the substrate due to the elastic preload.

[0018] The drive 12 has a pneumatic cylinder 24, which is fixedly mounted on a bracket 26. A piston rod 28 of the pneumatic cylinder carries a plate carrier 30 at its free end, on which the individual pin slide plates 10 are mounted parallel to one another.

[0019] The pneumatic cylinder 24 is a double-acting pneumatic cylinder whose piston (not shown) separates two pressure chambers, each connected via a valve 32 or 34 to a pressure line 36 and a vent line 38. The valves 32, 34 are electronically controlled by a control device 40.

[0020] When the labels and substrates 14 have reached their transfer position, the control device 40 activates the lower valve 34, so that pressure is introduced into the lower pressure chamber of the pneumatic cylinder via the pressure line 36 and the piston rod 28 extends. When the pin slide plates 10 have been raised far enough that all pressure pins 18 lying within the footprint of the substrate 14 have been pressed in by a certain spring travel, the valves 32, 34 are switched so that the lower pressure chamber is vented and the upper pressure chamber is pressurized, so that the stroke direction of the piston rod 28 is reversed and the pin slide plates 10 execute a downward stroke until the lower end position is reached again.

[0021] As with reference to Fig. 2, each pressure pin 18 is assigned a touch sensor 42. All touch sensors 42 of a pin slide plate are connected in series by a line 44. A transponder 46 is arranged on each pin slide plate 10 and can be connected to the line 44 in various longitudinal positions via reversible connecting lines 48. If all touch sensors 42 located between the connection points of the two connecting lines 48 deliver a touch signal, the section of the line 44 connecting these touch sensors is electrically conductive, so that a current generated by the transponder 46 can flow in a circuit formed by the connecting lines 48 and the relevant section of the line 44.

[0022] The transponder 46 receives its operating power from another transponder 50, which is integrated into the control device 40. As soon as a current flows in the connecting lines 48, the transponder 46 sends a signal to the transponder 50. As soon as the transponders 46 of all pin-push plates 10 send such a signal to the transponder 50, this causes the control device 40 to switch from an upward stroke to a downward stroke, so that the stroke movement of the pin-push plates is reversed. In this way, it can be ensured that the stroke of the pin-push plates 10 is limited to a value at which all pressure pins 18 that can touch the substrate 14 are sufficiently compressed, while at the same time ensuring that the compression travel of the pressure pins 18 is not exceeded, thus limiting the pressure force to a permissible value.

[0023] In a modified embodiment, only one of the pin slide plates 10 of the pressure device needs to have the transponder 46, which can then be connected via connecting lines 48 to the lines 44 of all the pin slide plates.

[0024] If the dimensions and / or the stop positions of the substrates 14 change, the connecting lines 48 are reconnected so that the circuit only contains the touch sensors 42 of those pressure pins that are to come into contact with the substrate 14.

[0025] In Fig.2 shows one of the pressure pins 18 and the corresponding part of the pin slide plate 10 enlarged and shown in section. A guide pin 54 is attached to an intermediate wall 52 of the pin slide plate and extends centrally through a channel 56 formed in the pin slide plate. The lower part of the pressure pin 18 is received in the channel 56, while the upper part protrudes from the pin slide plate through an opening 58. The guide pin 54 is surrounded by a spring 60 that holds the pressure pin 18 in its upper end position. When the pressure pin is pressed deeper into the channel 56, the guide pin 54 enters a guide channel 62 formed in the pressure pin, and the spring 60 is compressed. A permanent magnet 64 is received in the lower end of the pressure pin 18 and surrounds the guide channel 62.In the channel 56 of the pin slide plate 10, a coil 66 is arranged in a certain longitudinal section, which surrounds the guide pin 54 at a distance and forms a channel into which the pressure pin 18 and thus also the permanent magnet 64 can be immersed.

[0026] The touch sensor 42 is formed by the permanent magnet 64, the coil 66 and a transistor 68 in the line 44. The base and emitter of the transistor 68 are connected to the opposite ends of the coil 66.

[0027] When the pressure pin 18 is pressed into the channel 56 so far that the spring 60 generates a sufficient pressure force, the permanent magnet 64 enters the coil 66, and a voltage is induced in the coil 66, which makes the transistor 68 conductive so that a current generated by the transponder 46 can flow through the relevant section of the line 44.

Claims

[1] Pressure device for pressing adhesive labels against a substrate (14), with a pin slide plate (10) with a plurality of pressure pins (18) which are arranged parallel to one another in a row along an edge of the pin slide plate and can be pressed back axially into the pin slide plate against a spring force, and with a control device (40) for controlling a pressure movement of the pin slide plate (10), characterized by that at least one of the pressure pins (18) has a touch sensor (42) which is designed to supply a touch signal to the control device (40). [2] Pressure device according to claim 1, wherein at least two of the pressure pins (18) have a touch sensor (42). [3] Pressure device according to claim 2, wherein all pressure pins (18) have a touch sensor (42). [4] Pressure device according to claim 3, wherein the touch sensors (42) are connected in series by a line (44) such that a current can flow in the line (44) only when all touch sensors (42) deliver the touch signal. [5] Pressure device according to claim 4 with interchangeable connecting lines (48) through which a user-selectable section of the line (44) can be connected to a power source and an AND-linked touch signal is transmitted to the control device (40) when a current flows in the section of the line (44). [6] Pressure device according to claim 5, wherein the power source is a transponder (46). [7] Pressure device according to one of the preceding claims, with a transponder (46) for wireless transmission of the touch signal to the control device (40). [8] Pressure device according to one of the preceding claims, wherein the movement of the pressure pin (18) relative to the pin slide plate (10) drives an energy generator which supplies the operating energy for the touch sensor (42). [9] Pressure device according to one of the preceding claims, in which a pneumatic drive (12) is provided to control the pressure movement of one or more pin slide plates and in which the control device (40) is arranged to switch the drive (12) from forward stroke to reverse stroke as soon as the touch signal of the touch sensor (42) or of all touch sensors from a selected group of touch sensors is present.

Images