FR2878183A3 - Measuring device for leader pins of screw of plastic extrusion die comprises ring bell with parallel surfaces and threaded openings perpendicular to the surfaces into which a micrometer is placed - Google Patents

Abstract

The opening comprises rectifying leader pin bushing (16) having threading to prevent loosening during rotation and a hole (22), guiding the axis of grinding wheel.

Description

The present invention relates to a device for measuring and locating,

  Precisely, all along the width, the setting of the opening of the throttle bar of a plastic extrusion die, and maintain in state this device during the life of the die.

  Currently, there is no simple device for accurately identifying the opening of a throttling bar of an extrusion die. Existing devices allow only a visual, non-quantifiable observation from the pin heights of the sets of throttle bar settings. If one of the studs breaks, it is no longer possible to use the system without completely dismantling the die and without rectifying all the heads of the studs. Another existing device has pins engraved on the nuts of the throttle bar adjustment sets. After a few manipulations these marks are rendered illegible by the friction of the tightening wrench and loosening of these nuts. Another device uses a computer-controlled robot that retranscribes, the rotations of the nuts of sets of throttle bar settings, in depth. This device is complex and can not be economically mounted on small dies. In the absence of quantified information on the opening of the throttle bar, it is impossible, during manufacturing changes, to identify with a setting of a previous production. To find the right setting of the choke bar, it will proceed by successive approaches by measuring the effect on the product manufactured. It follows a waste of time and waste.

  The entire device according to the invention overcomes these disadvantages. It comprises a device for rectifying the surface of the head of the stud of the throttle bar adjustment assembly, and this parallel to the reference upper face of the die on which it bears. This device is used both for surfacing the head of a bolt replacing a broken bolt, and for surfacing the bolt heads of a die not yet equipped with this invention. This device consists of a cylindrical bell-shaped ring whose rectified upper and lower faces constitute the reference surfaces. This bell ring is placed on the upper face of the die as a reference, encompassing the set of adjustment of the throttling bar. A grinding guide ring screwed in the upper part guides the axis of a grinding wheel used to grind the head of the stud parallel to the upper reference surface of the die. The surface of the head of the stud thus ground will be in contact with the key of the micrometer used in the second device. The second device, derived from the first, makes it possible to measure using a depth micrometer the height of the stud relative to the upper surface of the die as a reference, and thus quantifies the value of the opening of the bar. throttling to the right of the set of adjustment. It is then possible, conversely, to precisely preset the die, by adjusting to the right of each set screw, the relative heights of the stud heads to the values corresponding to the openings measured during the previous setting of the throttling bar. This second device consists of the same bell ring used in the first device in which the grinding guide ring screwed in the upper part has been removed. By wedging the depth micrometer on the top surface of the bell ring, the micrometer key comes into contact with the ground surface of the stud head, thereby measuring its relative height relative to the reference surface. This height, deduced from the initial relative height of the same stud measured when the throttling bar, at the right of this set of adjustment, was closed, quantifies the opening of the throttling bar.

  According to the particular embodiment: - the bell ring may have two parallel faces and an orifice perpendicular to these two surfaces in which is introduced a depth micrometer resting on the upper surface of the bell and measuring the relative height of the head of the stud.

  - The bell ring may have two parallel faces and a threaded orifice perpendicular to these two surfaces in which is screwed a grinding guide ring having a thread perpendicular to the contact surface and having a hole parallel to the thread for guiding the axis of the grinding wheel during surfacing of the head of the studs. - The orifice of the bell ring and the threaded guide ring may comprise a so-called left-hand thread preventing loosening of the grinding guide ring during the rotation (in the opposite direction) of the grinding wheel of the heads of the studs.

  the thread of the bell ring and the thread of the grinding guide ring may be fine pitch threads to ensure that the contact surface of the grinding wheel with the head of the stud will be parallel to the reference surfaces of the bell .

  The device can also be used to shape the heads of the studs of the lip adjustment screws during the life of the die. The device can also be used to measure accurately, throughout the width, the opening of the lip extrusion dies of plastics to facilitate the settings thereof.

  The accompanying drawings illustrate the invention: Figure 1 page 1/6 shows in section, a plastic extrusion die with a throttling bar and its adjusting member, and a lip with its component. setting.

  Figures 2 and 3 page 2/6 represent in two different positions the throttling bar and its adjustment set.

  With reference to these drawings, the throttling bar (1) slides in its housing (2) located on the upper part of the die (3) to form locally an opening restriction (eu?) Between the throttling bar (1) and the lower part of the die (4). This opening serves to locally regulate the flow of plastic material arriving in the channel (10) depending on the desired flow at this location. An adjusting member is constituted by a stud (5) fixed in the throttling bar (1) and having two opposing plates for locking it in rotation by means of the ring (6) provided with an orifice suitable, a nut (8) with double threads differential pitch coming to screw on the stud (5) and unscrew on the ring (7). Screws (9) block the two rings (6) and (7) in rotation. When turning the nut (8), it raises the stud (5) and thus the throttle bar (1). The opening (em) of the throttling bar (1) increases. By unscrewing the nut (8), it drops down the stud (5) and the throttle bar (8). The opening (em) of the throttling bar (1) decreases.

  The adjustment assembly described above is generally referred to as the throttle bar adjustment screw. At an opening (em) of the throttle bar (1), corresponds strictly a relative height (hm) of the head of the stud (5) of the adjusting screw Ila throttle bar (1). When the throttle bar (1) is closed, at its opening (e0) corresponds a relative height (h0) of the stud head (5) of the throttle bar adjusting screw. The opening (em) of the throttle bar (1) to the right of the adjusting screw is characterized by the value (hm - ho = em - e0). The lip of the die (25) has a similar device. Its opening (1m) serves to locally adjust the thickness of material exiting the extrusion die.

  Figures 4 page 3/6 shows, in reduced scale, in bottom view and in section, the upper part of an extrusion die.

  Figures 5 and 6 show, on a reduced scale, two of the sets of throttle bar set screws.

  With reference to these drawings, the throttling bar (1) comprises in our example, 25 "sets of adjustments" that we will call "adjusting screw" of the throttling bar. The throttling bar (1) adjusts the distribution of the flow of material flowing in the channel (10) along the width of an extrusion die. Each of the throttle bar adjustment screws may have a different setting than the other 24. Each manufacturing may require changing all of these settings. Two side plates (11) close the ends of the width of the die. The lip (25) generally comprises a similar device "sets of adjustment" called "lip adjustment screw". Each manufactured product thickness may require a different adjustment. It is therefore important to be able to identify, to be able to reproduce from one manufacture to another, the settings of all these adjustment screws.

  Figure 7 page 4/6 shows the device in the grinding phase of the head surface of a stud of a throttling bar adjusting screw. A cylindrical bell-shaped ring (15) has a rectified lower surface (20) parallel to its upper surface (19). On the latter is screwed in its center (18) a grinding guide ring (16). It is itself pierced in its center (23) to receive the axis (14) of the grinding wheel (13) used to grind the surface of the head of the stud (5) of the bar adjustment screw. constriction. The axis (14) of the grinding wheel (13) freely rotates in the grinding guide ring (16). It can be rotated by an electric drill. The lower face (20) of the bell ring (15) is placed on the top of the die (3), on the reference surface thereof, and includes the set of the adjusting screw of the bar of throttle composed of its stud (5), its nut (8) and its two rings (6 and 7). A pressure on the drill in rotation makes it possible to rectify the surface of the head of the stud (5). The initial relative height (HO) of each rectified stud head (5) can be measured when the throttle bar (1) is completely closed. After the grinding operation is completed, the grinding ring (16) and the grinding wheel (13 and 14) are removed from the bell ring (15).

  Figure 8 page 5/6 shows the device in the measurement phase of the opening of the throttle bar to the right of a set screw thereof. The bell ring (15) is placed on the top of the die (3), on the reference surface thereof, and includes the set of the adjusting screw of the throttle bar composed of its stud (5). ), its nut (8) and its two rings (6 and 7). A depth micrometer (17) is placed on the upper reference surface (19) of the cylindrical bell ring (15). Its probe is brought into contact with the ground surface of the stud head (5) and thus measures specifies its relative height (Hm). The initial relative height (HO) of each dowel head (5) is measured when the choke bar (1) is completely closed. The value of the opening (em) of the throttle bar (1) to the right of the adjusting screw is calculated by subtracting the initially measured value (HO) when the throttle bar (1) was completely closed from that measured (Hm) is: (HO - Hm).

  Figures 9, 10, 11, 12, 13, 14 and 15 page 6/6 show separately the components of the devices described above.

  Figures 9, 10 and 11 show the grinding guide ring for receiving the grinding wheel.

  Fig. 9 shows the grinding guide ring (16) for a front view. The grinding guide ring (16) will be made by turning with a fine pitch external thread (23) on the left. Its bore (22) will be adapted to the diameter of the axis (14) of the grinding wheel (14) existing commercially to leave an operating clearance of 0.2 to 0.3 mm.

  Figure 12 shows the grinding wheel of the surface of the heads of the studs of the adjustment screws of the throttle bar or the lip. It has an axis of rotation (14) attached to an electric drill and an abrasive disc (13). The grinding wheel is commercially available.

  Figure 13 shows in section the cylindrical bell (15). Figure 14 shows a top view of the same bell. As an indication, the cylindrical bell (15) will be made by turning. Its lower surface (19) and its upper surface (20) will be rectified parallel. The internal bore of the cylindrical bell (15) will be at least 8 mm greater than the outer diameters of the rings (6 and 7) of the adjusting screws. The wall will be about 7 mm thick. A fine-pitched left-hand internal thread will be made in the inner hole (18).

  Figure 15 shows the depth micrometer (17) for measuring, with an accuracy of 0.02 mm, the height of the heads of the studs of the throttle bar or lip adjustment screws. The depth micrometer (17) is a commercial 0-25 mm micrometer. The device according to the invention is particularly intended to facilitate the adjustment of the throttling bar and the lip of extrusion dies of plastics.

Claims (6)

-7-CLAIMS   1) Device for accurately measuring, throughout the width, the opening of the throttling bar (1) of extrusion dies of plastics to facilitate the adjustments thereof, characterized in that it comprises a bell ring (15) having two parallel faces (19 and 20), and an orifice (18) perpendicular to these two surfaces into which is introduced a depth micrometer (17) resting on the upper surface (19). ) of the bell (15) and measuring the relative height of the head of the stud (5).   2) Device derived from the device 1 and used to shape the stud heads (5) of the adjusting screws of the throttling bar during the life of the die, characterized in that it comprises a bell ring ( 15) having two parallel faces (19 and 20), a threaded orifice (18) perpendicular to these two surfaces and in which is screwed a grinding guide ring (16) having a perpendicular thread (23) and a hole (22). at the contact surface (21) and for guiding the axis (14) of the grinding wheel (13) during the surfacing of the heads of the studs (5).   3) Device according to any one of the preceding claims characterized in that the orifice (18) of the bell ring (15) and the grinding guide ring (16) have a thread said left preventing its loosening during rotation (in the opposite direction) of the grinding wheel (13) of the heads of the studs (5).   4) Device according to any one of the preceding claims characterized in that the thread (18) of the bell ring (15) and the thread (23) of the grinding guide ring (16) are fine pitch threads ensuring that the contact surface of the grinding wheel (13) with the head of the stud (5) will be parallel with the reference surfaces (19) and (20) of the bell (15).   5) Device according to any one of the preceding claims that it can be used to shape the heads of the studs (5) of the lip adjustment screws (25) during the life of the die.   6) Device according to any one of the preceding claims by that it can be used to measure in a relative and precise manner, throughout the width, the opening of the lip (25) extrusion dies of plastics in order to facilitate the settings of this one.