DE1952573A1 - Measuring device for the deviation of a workpiece elongated in the feed direction from the feed path - Google Patents

Description

DAVY PLASTICS MACHINERY LIMITED, Poole , Dorset (England)

Measuring device for the deviation of a workpiece elongated in the feed direction from the feed path

The invention relates to a measuring device for the deviation a bendable workpiece elongated in the feed direction from the feed path.

In many cases it is desirable that an elongated, bendable workpiece be prescribed in the feed direction Feed path follows. Due to forces acting on the workpiece, in particular gravity, however, the workpiece tends to deviate from the feed path. It is therefore the task of the inventor application to create a measuring device for the deviation of the workpiece from the feed path.

The solution to this problem according to the invention provides an electromagnetic one mounted on one side of the feed path Radiation source in front of, furthermore at least two, on the opposite side of the source

009817 / U77

BAO ORIGINAL

The feed path perpendicular to the feed direction and parallel to the direction of the possible deviation are arranged next to each other radiation receivers which emit electrical signals representing the intensity of the incident radiation, as well as a comparison device which compares the signals and, if there is a difference from a setpoint value, a device representing the deviation of the workpiece from the feed path Emits control signal. The size of the deviation from the feed path is thus represented by an electrical control signal _p which can be used to bring the workpiece back to the desired feed path.

Accordingly, the device according to the invention furthermore comprise a device which receives the control signal and as a function of this control signal causes the workpiece to return essentially to the desired feed path.

If the feed path is horizontal, the workpiece tends to sag. Then at least one is the Radiation receiver positioned below the level defined by the feed path, and the aforementioned device, which receives the control signal, controls the Tensioning the workpiece to reduce the sag,

The electromagnetic radiation source is preferably a light source and the radiation receivers consist then from photocells. In certain applications, on the other hand, it may be desirable to use electromagnetic radiation to use from the infrared frequency band, and the receivers are then designed to be accordingly sensitive to infrared.

0098 17 / U77 BAD ORIGINAL

The invention is described below using an exemplary embodiment with reference to the accompanying drawing.
Show it:

Fig. 1 is a side view of a device according to the invention, in which the Workpiece, a extruded rubber or plastic strand, is wound up;

FIG. 2 shows a section II-II from FIG. 1; FIG. and

Fig. 3 is a section II-II according to FIG. 1 for the case that the bendable workpiece sags in relation to its position shown in FIG.

As shown in FIGS. 1 and 2, a bendable, elongated workpiece 1 of extruded plastic material leaves the discharge opening of an extruder 2 and passes through a tube 3 of usually rectangular cross-section through which steam is passed for further treatment of the workpiece. After leaving the tube, the workpiece 1 runs over a roller 4 and is wound onto a spool 5. It is desirable that the workpiece runs substantially horizontally along the 4 central axis of the tube 3; the axis defined by the extruder outlet opening and the run-off surface of the roller 4 is horizontal. Windows 6 and 7 are provided on opposite sides of the pipe. A light source is arranged near the window 6 outside the tube, so that the line coming from the source illuminates the workpiece 1. The window is attached at the same height as the workpiece 1. On the opposite side of the workpiece, two photocells 9 and 10 are attached one above the other to the outside of the window 7 in a position in which they are of

0098 17/1477

the light source 8 are evenly illuminated. the electrical signals emitted by the photocells, which represent the incident light intensity, receives a comparison device 11, in which the signals are compared and one of them resulting control signal is output. The output signal of the comparison device is fed to an amplifier 12 and, after amplification, is used to adjust the tension in the elongated workpiece. When the workpiece is in a Fig. 1 and 2 is the position shown, it is symmetrical to the photocells 9 and 10, so that the electrical output of each of the two cells is essentially is the same and the output from the comparison device 11 is essentially zero. When the tension is in the bendable workpiece has slackened so far that it is under the desired feed path through the steam pipe 3 drops (Fig. 3), then falls on the photocell 9 more and less light on the photocell 10, so that their electrical output signals change accordingly. A control signal released, which is amplified and used to increase the tension in the workpiece 1; the magnification the tension can be done e.g. by the speed of rotation of the coil 5 and thereby returned the workpiece to its central position in the tube will.

Since the signal from the comparison device 11 is a difference signal it does not matter whether one or both of the windows 6 and 7 is partially precipitated Water vapor are darkened as it is very likely that the falling on each photocell

0098.17 / U77

This reduces the light intensity by the same amount will*

In the embodiment shown, the radiation receivers are 9 and 10 positioned so that they are equally far above and below a plane that goes through the light source and the feed path are defined. Of course, the radiation receivers could also be unequal Distances from this level must be attached * As long as the signals from the radiation receiver for the Case are in a known relationship with each other when the workpiece is along the prescribed feed path running, the comparison device 11 can be set up so that it emits an output signal, when the workpiece deviates from the feed path, thereby changing the known relationship between the signals will.

9-g 1 7 / U 7 7

Claims (5)

Claims = = Z = = X 3Κ 2 Ij device for the deviation of an elongated in the feed direction, bendable workpiece from the feed path, characterized by a mounted on one side of the feed path electromagnetic radiation source (8), at least two, on the side opposite the source side of the feed path perpendicular to the feed direction and parallel to the direction of aöglichen Deviation radiation receivers (9, 10) arranged next to one another, which emit electrical signals representing the intensity of the incident radiation, as well as by a comparison device (11) which compares the signals and, if there is a difference from a nominal value, the deviation of the workpiece (1) from the Outputs control signal representing feed. 2. Apparatus according to claim 1, characterized by an adjusting device which receives the control signal and, as a function thereof, the return of the workpiece caused the feed path, 3. Device according to claim 1 or 2, characterized in that that with a horizontal feed path at least one of the radiation receivers is below the The level defined by the feed path lies in that the adjusting device controls the tension in the workpiece. 0Q9817 / U77 4. Device according to one of the preceding claims, characterized in that the radiation source is a light source and the radiation receiver is photocells are. 5. Device according to one of claims 1 to 3 »thereby characterized in that the radiation source emits infrared radiation and the radiation receiver is sensitive to infrared are. f. Device according to one of the preceding claims, characterized in that two radiation receivers provided and symmetrical to one by the radiation source and the plane defined by the feed path are positioned. ?. Device according to one of the preceding claims, characterized in that the feed path extends in the Länp> ■ direction d'zrch a pipe, in the wall windows permeable to electromagnetic radiation are used. Π Q 9 9 ι 1 / -% l ^ vf BAO ORIGINAL Blank page