Patent Application
20060104331
The invention relates to an apparatus for measurement, monitoring and/or regulation of a temperature in particular the temperature of the mold wall of an injection mold, by means of at least one measurement element which pulls through a sensor body in a corresponding hole at least as far as its outer walls.
The measurement, monitoring and regulation of a temperature is important and necessary in many manufacturing areas. The monitoring of the temperature of an injection mold, as is described, for example, in DE 101 14 228 A1, is mentioned merely by way of example. The entire injection process is controlled by means of appropriate thermal measurement elements which determine the mold wall temperature. For this reason, these thermal measurement elements are extremely important.
In known thermal measurement elements, the corresponding supply line is located loosely in a sensor body, with the measurement elements projecting out of the end surface of the sensor body, where they are fixed by means of a weld droplet or the like. This results in the end surface being irregular by virtue of the layer of the weld bulge between the medium to be measured and the measurement element, which leads to considerable sensor inaccuracies.
Furthermore, a thick mounting sleeve is provided on the equalizing line, and forms the transition from a metal tube between the mounting sleeve and the sensor body to a flexible cable. This mounting sleeve is also used as strain relief for the measurement elements in the sensor body. However, it has the disadvantage that a space must be left free for it in the injection mold, and this represents a weak point in the mold.
The present invention is based on the object of providing an apparatus and a method for production of this apparatus, by which means these disadvantages are avoided. The measurement elements should be securely fixed without the accuracy being adversely affected. Furthermore, the apparatus should be kept as thin as possible in order to weaken the injection mold as little as possible (cable duct).
In order to achieve this object, the measurement element is firmly clamped in the sensor body and/or in a crimping sleeve in front of the sensor body.
This ensures that the measurement elements remain in their desired position without having to be fixed by spot welds. The crimping provides strain relief for the measurement elements. There is no need for a thick mounting sleeve, so that the entire equalizing line can be kept thinner.
The idea of the invention covers the measurement elements being fixed by crimping in the sensor body and/or in corresponding holes. The crimping process is then carried out as close as possible to the tip of the sensor body, so that the measurement elements cannot escape from their desired usage position.
In some cases, it is even sufficient for only the equalizing line to be fixed in the crimping sleeve. However, the measurement elements could then still move back in the holes in the sensor body if, for example, pressure were exerted from the end surface. In one preferred exemplary embodiment, both the sensor body and the crimping sleeve are therefore crimped.
Should it be possible to insert the measurement elements into the holes in the sensor body such that their end surfaces are located exactly on the same plane as the end surface of the sensor body, then it would be sufficient for them just to be inserted into the holes, and for the crimping process then to be carried out. However, in order to achieve exact positioning of the end surfaces of the measurement elements on the same plane as the end surface of the sensor body, it has been found to be advantageous to allow the measurement elements to project slightly beyond the end surface of the sensor body, and to fix them there by a weld or solder droplet. The crimping process can now be carried out, after which the weld or solder droplet is ground off together with the ends of the measurement elements, thus ensuring that the end surfaces of the measurement elements are finally located on the same plane as the end surface of the sensor body. However, in this case, it is not absolutely essential to fix the measurement elements. Separate protection is therefore also desirable to ensure that the measurement element projects out of the hole, possibly being covered with a weld of solder droplet, and being ground off.
In one preferred exemplary embodiment, the equalizing line has external insulation composed of glass silk/Kapton. This external insulation insulates the equalizing line from the hot injection mold.
In addition, the invention provides for an extraction thread to be adjacent to the crimping sleeve, so that the sensor body can easily be pulled up, for example, from a hole in the injection mold by means of an appropriate tool.
Further advantages, features and details of the invention will become evident from the following description of preferred exemplary embodiments and from the drawing, in which:
An apparatus R according to the invention for measurement of the temperature, for example of the mold wall of an injection mold, has, as can be seen in
The sensor body 1 is adjacent to a crimping sleeve 7, onto which an extraction piece 8 with an extraction thread 9 is plugged. The crimping sleeve 7 and the extraction piece 8 surround an equalizing line 10, with another insulating sleeve 11 being provided between the equalizing line 10 and the crimping sleeve 7.
The two measurement elements 4 and 5 project out of the equalizing line 10 and engage in the longitudinal holes 2 and 3.
At the other end, the equalizing line 10 ends in a sleeve 12, where it branches into the connecting lines 13 and 14.
The method of production of the apparatus according to the invention will be described in more detail in the following text with reference, inter alia, to
The extraction piece 8, the crimping sleeve 7 and the sensor body 1 are pushed onto the free end of the equalizing line 10, beyond the sleeve 12. In the process, care must be taken to ensure that the measurement elements 4 and 5 find their longitudinal holes 2 and 3. In this case, as shown in
A defined spot weld 15 is now applied, with wide tolerances, to the end surface 6. After this, this spot weld 15 is ground off or the weld bulge is ground off to the level of the planar end surface 6.
In contrast,
In one preferred exemplary embodiment, the crimping sleeve 7 is also crimped, resulting in the equalizing line 10, or its front area, being fixed in the crimping sleeve 7. This is also used for strain relief for the equalizing line 10. The crimping sleeve 7 is, of course, not crimped until the crimping sleeve 7 has been plugged onto the sensor body 1.
The extraction piece 8 can be connected to the crimping sleeve 7 even in advance, for example by welding or adhesive bonding, although a threaded connection could also be provided. An appropriate tool can be screwed onto the extraction thread 9 of the extraction piece 8 in order to pull the crimping sleeve 7 and the sensor body 1 out of the usage position in the mold wall of an injection mold.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP03/14092 | 12/11/2003 | WO | 9/2/2005 |
