KR100835773B1 - Needle punching machine equipped with a penetration measuring device - Google Patents

Abstract

The present invention relates to a device for needleworking a fabric structure consisting of a plurality of overlapping layers (12), which is a vertically movable needlework table (10) and a predetermined sharp needle (18) placed vertically on the needlework table. And a driving means for transmitting a vertical reciprocating motion forming the lowest point of the needle puncture to the needle head, further comprising an upper surface of the fabric structure at the lowest point of the needle puncture. Measuring means 36 are provided for measuring the position of the measuring means, which are preferably located in the middle plane of the needle head perpendicular to the advancing direction of the fabric structure.

Description

Needle punching machine equipped with a penetration measuring device             

FIELD OF THE INVENTION The present invention relates to the manufacture of needlework fabric structures used in the manufacture of protective parts used at high temperatures, structural parts of rocket engines, or indeed high performance brake discs for aviation or ground transport.

Brake discs must withstand braking, which causes very large shear forces, which is noticeable in aircraft due to the large stresses applied to the brake discs.

In order to withstand these shear forces, which cause the effect of cracking into thin pieces, the disk must be made to minimize structural non-uniformity. Non-uniform discs have localized areas with different stress characteristics, which significantly increases the risk of rupture.

Conventionally, a brake disc consists of a reinforcement fabric structure consisting of a plurality of layered layers which are needled together by a set of sharp needles penetrating in the Z direction, ie across the layers. After being cut to the appropriate size, the fabric structure is carbonized, then densified using the matrix forming material, and finally subjected to selective heat treatment. The layers overlap the support. The downward movement step is generally performed on the support when overlapping layers are formed, and the needle work is carried out on several layers. The mechanical properties of the final product thus obtained depend very much on the actual needle working density used in the reinforcement fabric structure. Here, the term "actual needle working density" is a function of the number of needles per cubic centimeter (cm ³ ) understood as the fundamental volume of the fabric structure, and therefore the needle working density per unit area, the range of perforation in the Z direction, and the downward movement stage. The size and operating characteristics of the needle.

Although some needle work methods provide good results, in particular by acting on the size of the downward movement step, today's needle work methods are difficult to achieve the perfect uniformity required. In US Pat. No. 4,790,052 it was proposed that the distance between the needle and the layer support be increased for each layer overlaid by the same distance as the thickness of the needled layer. In addition, European Patent No. 0,736, 115 attempts to obtain a constant thickness for several overlapping layers by adopting a moving step for layer supports having a decreasing size in accordance with a predetermined relationship.

The drawback of these methods is that although the size of the downward movement step for the layer support is generally calculated in advance based on the theory, in particular according to the number of layers forming the fabric structure, the actual depth of drilling of the needle is not taken into account. Unfortunately, this variable must be known to ensure the uniform needle density required to obtain the final fabric structure with good uniformity. In addition, the thicker the fabric structure, the greater the room for error in knowing the depth of drilling.

EP 0,695,823 attempted to better know the depth of puncture of the needle by means of a feeler roller which measures the position of the upper surface of the fabric structure between the needle operations and is positioned out of the working area of the needle.

However, this method was unsatisfactory because the fabric structure was compressed under the action of the needlework force and could not be detected by measurements made. This method, which does not take into account the deformation of the fabric structure, does not accurately know the actual depth of drilling of the needle.

Accordingly, the present invention enables to measure the actual puncture depth of the needle in the fabric structure for needle work in a manner that takes into account the deformation of the structure while working with the various layers constituting the fabric structure, the needle to solve the above defects The purpose is to provide a working device and a method associated with it.

This object is achieved by a needleworking device of a fabric structure consisting of a plurality of layered layers, the device comprising a needlework table with a vertically movable needlework table, and a predetermined sharp needle placed vertically on the needlework table; And a driving means for driving the needle head to transmit the vertical reciprocating motion to form the lowest point of the needle perforation on the fabric structure, the position of the upper surface of the fabric structure being positioned at the lowest point of the needle perforation. Characterized in that it further comprises a measuring means.

Thus, by placing the measuring means on the needle plate, it is possible to consider the range in which the fabric structure is compressed under the influence of the needle working force, thereby accurately measuring the actual drilling depth of the needle.

Preferably, the measuring means is located in the middle plane of the needle head perpendicular to the advancing direction of the fabric structure.

In a preferred embodiment, the measuring means for measuring the position of the upper surface of the fabric structure is provided with an optical assembly for carrying out the measurement without contact. Preferably, it has a laser emitter and receiver of the beam type.

In another embodiment, the measuring means may be provided with a mechanical filler for contact measurement.

Preferably, a sensitive or optical sensor is provided to measure the lowest point of the needle puncture, and to control the vertical movement of the needle work table according to the position of the upper surface of the fabric structure measured at the lowest point of the needle puncture by the measuring means. Processor means is provided.

The present invention also provides a method of using the aforementioned needlework apparatus for making a fabric structure, and relates to a fabric structure obtained by the method, wherein the position of the top surface of the fabric structure is preferably the entire length of the fabric structure. Measured by simultaneous measurements performed in real time over.

The features and advantages of the present invention will become more apparent with reference to the following description and attached drawings, which are given in a non-limiting manner.

1 is a schematic diagram of an apparatus according to a first embodiment of the present invention for needle working a fabric structure.

2 is a schematic diagram of an apparatus according to a second embodiment of the present invention for needle working a fabric structure.

3 is a side view of the device shown in FIG. 2 with its right side at the maximum position of the needle puncture;

Two embodiments of a device for needle flat fabric structures are shown in FIGS. 1 and 2. Naturally, the present invention is not limited to making flat structures, but the sheet or fabric is twisted in an annular and spiral shape to form a flat overlapped sound or wound on a mandrel to form a superimposed sound, and the fiber sheet is wound around the structure. The invention can also be applied to making.

Typically the apparatus is provided with a needlework table 10 for supporting a layer 12 or sheet having a width and a length, which is supplied one after the other so as to overlap in successive layers, depending on the final structure to be made. do. The table lies underneath the needle head 14 with a predetermined sharp needle 18 mounted to the needle plate 16, which head is reciprocated vertically by one or more crank assemblies driven by one or more motors. You can exercise. A stripper 22 fixed to the frame 24 of the needlework device is mounted on the needlework table to prevent the fabric structure from being pulled up when the needle is raised. Of course, both the table and the stripper are formed by passing through respective holes 26 and 28 for the needle to pass through. The table moves vertically, for example, under the drive of a drive device 30 consisting of a worm screw driven by a motor. Two sets of drive rollers 32,34 (also known as inlet presses and outlet presses) placed upstream and downstream of the needle working device serve to transport the fabric structure horizontally towards the needle head.

The present invention includes measuring means 36 positioned on the needle head 14 to measure the position of the top surface of the fabric structure, thereby measuring the actual depth of drilling of the needle of the fabric structure at the lowest point of the needle perforation. Since the stroke of the needle is constant with respect to the frame to which it is connected and the needle work table is located at a known distance to the frame, the depth through which the needle penetrates the fabric structure is the material present between the needle work table and the measured top surface. It is easy to see that it follows the thickness of.

To this end, the measuring means 36 are fixed to the frame 24 and the needle plate 16 and the stripper 22 have holes 38 and 40 respectively to allow the measuring means to interact with the upper surface of the fabric structure. This is pierced.

In the illustrated embodiment, this interaction can occur without contact (as the position of the top surface of the fabric structure is measured remotely) or in contact (by lowering the mechanical filler to the top surface of the fabric structure).

1 shows a preferred embodiment of the invention in which the non-contact measuring means consist of an optical measuring assembly such as a laser emitter and receiver 42. The emitter sends a laser beam through the needle plate and the stripper toward the top surface of the fabric structure, and the beam is reflected back to the receiver. The distance between the spinner and the needlework table can be known from previous measurements, so that the distance between the spinner and the top surface of the fabric structure can be measured by analyzing the reciprocating path of the laser beam, which is a function of the fabric structure supported by the needlework table. It is enough to get the thickness exactly. In addition, in order to avoid difficulties due to the prominent flaws of the fabric structure, the laser assembly is preferably a wide beam type (since this type of laser performs the integration effect by measuring over the full width of the beam). Of course, it is possible to use an optical measuring assembly operating in infrared, but is not necessarily limited to infrared.

FIG. 2 shows another embodiment, ie consisting of a mechanical filler in which the measuring means is formed by an inner piston 44 fixed to the frame 24, the outer sleeve 46 being slidably mounted, This sleeve has a somewhat rounded end that is in direct contact with the fabric structure (after passing through the needle plate and stripper). The sliding of the sleeve is preferably driven to be controlled by injecting a fluid, such as compressed air, into the piston from the control module 48 fixed to the frame 24. The pressure of the fluid is adjusted according to the nature (hardness or reaction, etc.) of the fabric structure to be needled, so that the sleeve does not bounce back from the fabric structure. The sleeve also has, at its upper end, a reflective collar 50 which interacts with an optical measurement assembly, such as a laser (or infrared) emitter fixed to the frame and receiver 52. The radiator guides the beam at the collar in the sleeve and reflects it to the receiver. When the tip of the filler is in contact with the needle work table, the distance between the spinner and the receiver can be known from previous measurements, thus measuring the distance between the spinner and the receiver when the tip is in contact with the top surface of the fabric structure. By analyzing the reciprocating path) is sufficient in this case to accurately determine the thickness of the fabric structure conveyed by the needle work table.

In all the embodiments described above, the measuring means 36 is preferably located in the mid plane of the needle head 14 (although, of course, it may be considerably deviating therefrom) perpendicular to the direction in which the fabric structure is advanced. If the fabric structure is in the form of two adjacent plates advancing parallel to each other under the needle head, the measuring means can be doubled. In the structure as shown in Fig. 3, the needle head may have two independent needle plates positioned side by side, with the measuring means being generally located in the center of each needle plate. For the sake of understanding, FIG. 3 shows the device according to the embodiment in two distinct positions, one of which positions (left part of FIG. 3) corresponds to the resting position on which the needle head is raised. And the other (right part) corresponds to the position of the needle head at the lowest point of the needle puncture.

The lowest point of the needle puncture is measured in real time by a sensor 54, for example an sensitized or optical type, which is fixed to the frame and, for example, a special cam of the crank assembly 20 which controls the vertical reciprocation of the needle head. Interact with features 56. The cam portion 56 preferably acts to measure a period of time (not just one, but an instantaneous instant measurement) during the downstroke of the needle head close to the lower point, whereby the measuring means 36 is operated to A measurement can be obtained from which the processor means 58 connected to both the sensor 54 and the measurement means 36 can measure a first average value for the thickness of the layers being needled. These measurements are repeated over and over after the horizontal advancement phase of the fabric structure, and a series of values obtained at the end of a given path act to measure the actual mean depth of drilling of the needle, and on the basis of which it is connected to the processor means 58 The driving device 30 for driving the needle work table can automatically move the needle work table vertically to receive the passage of the next fabric structure. The size of the downward movement stage of the table is measured by the needle to the measured depth. Controlled to penetrate the structure.

Thus, the needle working method implemented in the apparatus according to the present invention can be summarized as follows: first, the second layer is superimposed on the first layer on the needle working table, and the two layers thus superimposed on the needle under the predetermined conditions. Joined together by sharp needles in the head. Thereafter, the needle work table is moved relative to the needle head in a downward movement step of the size measured according to the position of the upper surface of the two overlapping layers measured at the lowest point of the needle puncturing by suitable measuring means. Finally, the third layer is overlaid on the two preceding layers, which are joined to the two preceding layers under the same predetermined conditions. These steps are repeated for the next layers until the fabric structure is formed to the desired thickness.

The method implemented with the above-described needle work device consists of first placing one or two overlapping layers on the needle work table 10, which are driven by the driving rollers 32, 34 to the entire length of the fabric structure. They are joined together by working with the needle plate 16 while being moved horizontally across. Thereafter, the table is lowered in the movement of the measured size so that the second layers can overlap and are then needled into the other two layers and so on until the desired thickness is obtained.

In the present invention, the downward movement step of the measured size is not a fixed size or is not in a predetermined descent relationship and precedes the fabric structure measured at the lowest point of the needle perforation so as to obtain a desired actual needle working density for the fabric structure. Determined from the actual depth of puncture of the needle in the layers, the density may be constant or vary through the thickness of the fabric structure. Thus, the position of the top surface of the fabric structure is measured in the middle of the needle to determine the size of the downward movement stage of the needle work table, allowing the needle to penetrate the fabric structure to a determined depth.

Claims (10)

A needle head 14 having a vertically movable needle work table 10, a plurality of sharp needles 18 placed vertically on the needle work table, and a vertical reciprocating motion forming the lowest point of needle puncture in the fabric structure. In the device for needle working the fabric structure consisting of a plurality of overlapping layers (12) with drive means for driving the needle head for delivery, And a measuring means (36) positioned on the needle head to measure the position of the upper surface of the fabric structure at the lowest point of the needle puncture. The needle working apparatus as claimed in claim 1, wherein the measuring means is located at an intermediate plane of the needle head perpendicular to the advancing direction of the fabric structure. The needle working apparatus according to claim 1 or 2, wherein the measuring means for measuring the position of the upper surface of the fabric structure is provided with an optical measuring assembly for performing the measurement without contact. The needle working apparatus according to claim 1 or 2, wherein the optical measuring assembly is composed of a laser radiator and a receiver (42). 5. The needle working apparatus according to claim 4, wherein the laser radiator and the receiver are of a wide beam type. The needle working apparatus according to claim 1 or 2, wherein the measuring means for measuring the position of the upper surface of the fabric structure includes mechanical fillers (44 to 52) for contact and measurement. The needle working device according to claim 1 or 2, further comprising an inductive or optical sensor (54) for measuring the lowest point of needle puncture. 8. The apparatus according to claim 7, further comprising a processor means (58) for controlling the vertical movement of said needle work table in accordance with the position of the upper surface of the fabric structure measured by said measuring means at the lowest point of needle puncture. Needle working equipment. Superimposing a second layer on the first layer placed on the needle work table 10; Using the sharp needles 18 of the needle head 14 to join the two overlapping layers together under predetermined conditions; The needle operation table is moved relative to the needle head in a downward movement step of a size determined according to the position of the upper surfaces of the two overlapping layers, wherein the position of the upper surface is measured at the lowest point of the needle puncturing of the needle head; Superimposing a new third layer over the preceding two layers; Bonding the third layer to the two preceding layers under predetermined conditions; Continually repeating the above steps for a new layer, the movement being determined according to the position of the top surface of the fabric structure being measured and formed at the lowest point of the needle perforation; How to form a structure. 10. The method of claim 9, wherein the position of the top surface of the fabric structure is measured by averaging given instantaneous measurements in real time over the entire length of the fabric structure.

Images