CS207312B2 - Product from the cast plastic material,method and device for executing the same - Google Patents

Abstract

1319512 Strip fastenings SOC POUR LA RECHERCHE ET LE DEVELOPPEMENT TECHNOLOGIQUE SA 6 May 1970 [14 May 1969] 1034/73 Divided out of 1319511 Heading E2S [Also in Division Dl] A hooked piled fabric suitable for use in strip fasteners, consists of an extruded bace layer 20 of plastics material such as nylon from one surface of which project hooked pile-like elements 21. In the embodiment shown in the figure the elements are in rows, the hooks in adjacent rows facing in opposite directions. The hooks may be of rounded cross-section or may be triangular in crosssection as shown in Fig. 13, the latter configuration facilitating easy release of the elements from their forming moulds. (For Figures see next page)

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a cast plastic article for use as a first divisible switch member, the second member comprising a base and a plurality of hairy hooks projecting from the base, the article comprising a base band of plastic and a plurality of complementary hooks releasably attachable with the hooks of the first member and collectively protruding from the base. The invention also relates to a method for producing a cast plastic article as mentioned above, in which a plurality of casting cavities are formed, these casting cavities are displaced along a closed path, and a plastic material is injected into the casting cavities. The invention further relates to an apparatus for carrying out the method mentioned above, comprising a set of casting plates arranged in a closed path, each having a portion of at least one casting cavity, further comprising an injection mechanism for discharging plastic material into the casting plates and a casting plate drive assembly.

U.S. Pat. No. 3,196,490 to the inventor Erba discloses an apparatus for the injection molding technique for producing hook-like projections on a base web, which may be formed either as a carcass of a plastic-bonded fabric or as a plain web of plastic material formed concurrently with the crochet vý2 stupky. The apparatus comprises a set of shaping plates conveyed on a closed path, preferably circular, wherein the active surfaces of the shaping plates are provided with cavities for forming hook-like protrusions and these active surfaces lie in a bundle of planes passing through the axis of rotation of the set of shaping plates. In the working zone, the forming plates are pressed against each other by a mechanical device consisting of two sets of gears and a chain wheel chain system, in the remaining part of the closed track the forming plates are carried separately from each other, i.e. with gaps between adjacent forming plates, in the work zone.

The known apparatus described above has a very complex structure since periodic compression and subsequent separation of the molding plates requires a very complex mechanism, which is expensive in itself and requires high maintenance costs. Measures shall be taken to prevent any impurities from entering the adjacent surfaces of the forming plates in the working zone.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-described disadvantages of the prior art and to provide an improved cast plastic product, an improved manufacturing method and an improved apparatus for carrying out this method having a simple mechanical structure and thus inexpensive in terms of purchase and maintenance costs. had increased reliability in operation.

SUMMARY OF THE INVENTION The object of the present invention is to provide a cast plastic article, wherein the complementary hooks have a shank and a laterally directed hook portion protruding from the shank for anchoring the hooks of the first member, the hook portion having a first flat surface disposed in the first plane perpendicular to the base and is disposed all along one side of the first plane, and a second flat surface disposed in a second plane diverted from and intersecting the first plane, the second flat surface being disposed at an end portion of the hook portion of each hook.

According to a preferred embodiment of the invention, the hook portion of the hook has a curved shape.

According to a further preferred embodiment of the invention, the shank of each hook has at least two straight sides, each of which adjoins in the hook part of the hook a section of a collapsible, deployable straight line surface.

According to a further advantageous embodiment of the invention, the hooks are arranged in straight lines in a first direction and their hook parts are arranged in planes perpendicular to this first direction, wherein the hook parts of two rows of hooks of each pair of straight hook lines are arranged in a facing position.

The invention further provides a process for the manufacture of a cast plastic article as defined above, characterized in that the plastic material is fed by two separate feeders. channels from two separate pumps for filling the cavities by high pressure extrusion and the support belt is formed by low pressure extrusion, and the hooks and support belt are joined while the plastic material cools on the casting surface.

The invention further provides a device for carrying out the method as defined above, characterized in that the casting plates are arranged in at least three groups of forming plates, provided on their two parallel surfaces with hollow grooves and alternating planar intermediate plates in planes perpendicular to the axis of the main shaft of the device wherein the casting plate groups are arranged with their narrow lower surfaces on the base surface of the carrier wheel groove fixed to the main shaft of the device, the base of the groove having a regular polygon shape, the shaping plates being fixed to the carrier wheel by a fastening pin tightly seated in the circular holes of the shaping plates the insert plates are provided with circular holes formed with play around the fastening pins of the forming plates, each insert plate having a pair of rectangular holes in which a plurality of With the shaft protruding with the clearance of the circular slots in the forming plates, the adjusting shafts are supported at both ends in adjusting plates arranged adjacent to the support wheel and provided with traction rollers on their hips adjacent to the main shaft arranged in contact with cams mounted on the machine frame .

According to a preferred embodiment of the invention, each adjusting plate has a hydraulic cylinder mounted in a rectangular section attached to a guide pin inserted in the support wheel, the piston rod of the hydraulic cylinder being fixed in the radially outer part of the adjusting plate.

According to a further preferred embodiment of the invention, adjacent portions of the radially outer edges of the forming plates and the insert plates of each pair are rounded to form a cylindrical casting surface.

According to a further preferred embodiment of the invention adjacent to the groups of forming plates and liner plates, a tank for molten plastic material is arranged in a fixed position.

According to another preferred embodiment of the invention, the tank has a first outlet for the first type of plastic material and a second outlet for the second type of plastic material.

According to a further preferred embodiment of the invention, the tank has a discharge nozzle provided with a cylindrical surface portion forming a gap with respect to the casting surface formed by the groups of forming plates and liner plates and adjacent to the second outlet.

According to a further preferred embodiment of the invention, one side wall of the carrier wheel groove is provided with a peripheral recess at its upper edge.

According to a further preferred embodiment of the invention, a cross member is disposed adjacent to the discharge nozzle, provided with a pulley at its ends arranged in contact with the surface of the support wheel, the cross member being in abutment with the cylindrical spring supported on nuts screwed on a rod fastened in the frame.

A new and higher technical effect of the above-defined measures according to the invention is that, due to the new geometric shape of the hooks on the cast plastic product, these hooks are easily pulled out of the mold cavities of the molding plates of the device according to the invention and there is no danger that the hooks from the casting cavities could break. This allows a higher rate of production of the continuous cast product. At the same time, a very simple design of the device, its high reliability in operation and elimination of disturbances by impurities in the casting cavities are achieved.

An exemplary embodiment of the invention is shown in the accompanying drawings, in which Fig. 1 is a side view of the device according to the invention, with some components omitted for clarity; Fig. 2 is an enlarged cross-section of the casting wheel along line 2-2 of Fig. Fig. 3 is a longitudinal cross-sectional view of the casting wheel taken along line 3--3 of Fig. 2, Fig. 4 is an enlarged cross-sectional view of the casting wheel portion and extruder head; Fig. 6 is a sectional view similar to Fig. 5 showing another shape of the extruder die; Fig. 7 is an enlarged partial cross-section along line 7-7 of Fig. 2 with intermediate pieces in the outer position; Fig. 8 is another partial cross-section along Fig. 7 is a cross-sectional view taken along line 9-9 of Fig. 8 showing portions of several intermediate pieces and casting plates; Fig. 10 is an enlarged partial cross-sectional view taken along line 10-10 of Fig. 2 prior to separation; Fig. 11 is a cross-sectional view taken along line 11-11 of Fig. 2 showing the hooks partially released from the casting plate cavities; Fig. 12 is a perspective view of a cast plastic product according to the invention; Fig. 13 is a perspective view of a modified hook shape and an adjacent portion of the base to which it is attached, and Figs. 14 and 15 are two views of a modified hook.

FIG. 12 shows a short section of a base in the form of a continuous cast plastic belt 20 produced by the apparatus of the invention. A plurality of hair-like protrusions in the form of hooks 21 protrude from one surface of the strip 20, which are made in one piece with the strip 20 and protrude therefrom to a height of 1.5875 mm.

An apparatus for manufacturing this cast plastic product is shown in FIG. other images. According to FIG. 3, the device according to the invention has a main shaft 22 which projects to the right of the roller bearing 23, the outer ring of which is engaged in the lid 24 on the main frame 25. The main shaft 22 is further supported in a second bearing (not shown) in the main frame 25. with which the drive mechanism (not shown) for driving the main shaft 22 at the desired speed is associated.

A casting wheel 26 is mounted on an overlapping portion of the main shaft 22 projecting from the antifriction bearing 23 to the right. The support element of the various components of the casting wheel 26 is the supporting wheel. 27 (FIGS. 2 and 3), which, for example, is non-detachably connected to the main shaft 22 by welding. In the center of the thickness, the support wheel 27 has an annular groove 28 for receiving several groups of molding plates 29 and liner plates 30. One group of forming plates 29 with the insert plates 30 arranged alternately therebetween is shown in the upper part of Fig. 3 and another similar group is in the lower part of Fig. 3. There are eight groups A to H of the forming wheels around the circumference of the casting wheel 26. These groups are approximately in terminal contact with the annular groove 28, wherein the arcuate surfaces of the forming plates 29 and the insert plates 30 form a cam surface that aligns with the cylindrical surfaces 39 of the support wheel 27 on each side of the annular groove 28.

The side walls of the annular groove 28 laterally form groups A to H of the forming plates and liner plates 30. The depth of the annular groove 23 is such that it allows the insert plates 30 of each group A to H to move radially relative to adjacent forming plates 29, as described below. The mold plates 29 of each of these groups A to H are matched in their circumferential position by a fastening pin 31 that fits flush with the holes 32 in the mold plates 29 (FIGS. 2 and 3). As can be seen from FIG. 2, the lower surface of the annular groove 28 is octagonal and the groups A to H of the forming plates 29 are located radially away from respective planar base surfaces 32 of the annular groove 28.

The molding plates 29 of each of the groups A to H have on their opposite sides hook-like grooves 33 (FIG. 7) which are in the form of hooks 21 shown in FIG. 12.

Group A molding plates 29. and the liner plates 30 (FIG. 2) move slowly counterclockwise to an operating position toward the discharge nozzle 35 of the extruder for a suitable meltable plastic mass. This plastic flows under pressure through the discharge nozzle 35 to the first outlet 37 and the second outlet 33 (Fig. 4) The liner plates 30 (Fig. 7) are in their outer position so that their arcuate surfaces adjoin around the perimeter of the casting wheel 28 and also adjoin the arcuate surfaces of the forming plates 29 and the cylindrical surfaces 39 of the support wheel 27 on opposite sides of the annular groove 28 (FIG. 3).

In order to prevent the formation of burrs, i.e. thin pieces of plastic projecting from the surfaces of the cast hooks 21, the molding plates 29 and the insert plates 30 are prevented from moving apart. One way to prevent this movement is to create a radial gap 4D on the right side of group B (Fig. 7) with a depth greater than the depth of the hook grooves 33. As each group A to H moves towards the opening of the first outlet 37, plastic enters into the circumferential recess 48 and apply lateral pressure to prevent the forming plates 29 and the group insert plates 30 from being spaced apart. This pressure ceases after the plastic has cured. In a modified embodiment of the dispensing nozzle 41 (FIG. 6), an additional plastic channel 42 is provided upstream of the first outlet 37 and in line with the recess recess 40 (FIG. 7).

Two outlets 37, 33 achieve considerable flexibility. The first outlet 37 will inject plastic under high pressure through the pump 371, while the second outlet 38 will inject plastic at the lower pressure to form the web 44.

It is possible to use single outlets for supplying the molten mass to the hook grooves as well as to form the strip 44, however using two outlets 37, 38 and separate pumps

371, 331 for each outlet 37, 38 has the above advantages.

It is important that the dispensing nozzle 35 of the extruder is in the correct radial position with respect to the casting wheel 28, that is to the cylindrical surface 39 of the support wheel 27. To this end, it is supported across the extruder roller 46 near the dispensing nozzle 35. a rigid cross member 45 for axially controlling the extruder roll 46 is welded to the cylinder 46 or otherwise releasably attached to a flange 47 having a central bore through which the cylinder 46 passes. Four screws 48 are rotatably mounted in the bore holes of the flange 47 and screwed into threaded holes in the cross-member 45 for the desired limited adjustment movement.

At each end of the crossbeam 45, the rollers 49 are rotatably mounted in brackets 50 mounted on the left side of the crossbeam 45. The rollers 49 rest on the cylindrical surface of the support wheel 27. To discharge the discharge nozzle 35 of the extruder to the casting wheel 26 two rods 51 and 511 are provided in the extruder (FIG. 3). The rod 51 is screwed at its left end into a hole in the lid 24 of the main frame 25 of the device according to the invention. The rod 511 is screwed into the disc 241, which is supported by the second roller bearing 242 at the shoulder end of the main shaft 22. The disc 241 is held in a fixed position by fasteners (not shown).

The bars 51 and 511 pass freely through holes in the crossbeam 45 on each side of the extruder, and at the right end of each bar are compression cylindrical springs 52 and a pair of adjustment nuts 53. These cylindrical springs 52 keep the rollers 49 in contact with the cylindrical surface 39 When the rollers 49 are in such contact, the discharge spout 35 is at a proper distance from the casting wheel 26.

In certain circumstances, it is desirable to move the dispensing nozzle 35 from its operating position. This is accomplished by a slide 54 that moves along the rail 55 and is connected to the crossbeam by arm 56. The slide 54 engages a motion screw 57 to rotate the motor 58.

With this arrangement, the discharge nozzle 35 can be quickly moved away from the casting wheel 28 and can also be quickly moved back to the casting wheel 26. The pulleys 49 ensure that the surface of the discharge nozzle 35 is positioned correctly relative to the surface of the casting wheel 26.

With respect to the radial movement of the insert plates 30 and the positioning of the insert plates 30 and the forming plates 29 in groups A to H, although the fixing pins 31 fit in the holes in the forming plates 29, the insert plates 30 have holes 59 around the fixing pins 31 which are larger. diameter than the fastening pins 31 so that the insert plates 30 allow radial movement. As explained above, the forming plates 29 are mounted in a stationary position, with arcuate edges flush with the cylindrical surface 39 of the support wheel 27.

The insert plates 30 of groups A to H are movable radially outwards and inwards by means of a pair of adjusting plates 60 and 61 (FIGS. 2 and 3) having a triangular shape with rounded corners (FIGS. 1 and 2). The adjustment plates 60 and 61 are slidably mounted on opposite sidewalls of the support wheel 27.

An inner shaft 62 is attached to the inner narrow ends of each pair of adjusting plates 60 and 61, the outer ends of which are provided with follower rollers 63 and 64 which are in contact with the inner cam surfaces 65 and 66, respectively (FIG. 3). The inner cam surface 65 is formed in a stationary cam.

The inner shaft 62 extends through the opening 67 in the support wheel 27, the opening 67 being large enough to allow the necessary radial movement of the inner shaft 62 to move the liner. On the inner shaft 62 there is a bush 68 whose front faces keep the adjusting plates 60 and 61 at a correct distance from each other with respect to their sliding on the side walls of the support wheel 27.

At their outer ends, the adjusting plates 60 and 61 are connected by two adjusting shafts 69 (FIG. 9) which are spaced from one another at a distance corresponding to the arc length of the forming plates 29 and insert plates 30 of groups A to H. Thus, the insert plates 30 are held in a fixed position relative to the setting plates 60 and 61, and when in their outer position, the arch surfaces of the insert plates 30 are exactly aligned with the arch surfaces of the forming plates 29.

Each of the adjusting plates 60 and 61 of each pair has a hydraulic cylinder 71 disposed in a rectangular slot 72. The inner end of each hydraulic cylinder 71 is open to supply hydraulic fluid and is tightly connected to the supply line 73 (FIG. 3). On the piston rod 74 of the hydraulic cylinder 71, the thread is screwed into a hole in the outer part of the adjusting plate 60, 61.

The pair of adjusting plates 60 and 61 for shifting the insert plates 30 may be held in their outer radial position by any conventional means. To this end, the hydraulic cylinders 71 exert a hydraulic pressure which is generated by the liquid in the accumulator 75 mounted on the circular plate 76 (FIG. 1), attached in any conventional manner to the right side of the disc 241. The fluid from the accumulator 75 is supplied via line 73 to all hydraulic cylinders 71 of the eight groups A to H by the pipes 77 and 78 shown in FIG. 1. A pressure gauge 79 and a filling fitting 80 are connected to the pipes 77, 78.

The outer contours of the two inner cam surfaces 65 and 66 are the same and one of them is shown in Fig. 2. The task of the hydraulic cylinders 71 is to move the adjusting plates 60 and 61 of each group A to H before and during passage of the forming plates 29 and liner plates 30 around the discharge nozzle 35 of the extruder. The liner plates 30 are maintained in their outer position by the hydraulic pressure exerted in the hydraulic cylinders 71 for a sufficient time after extrusion and casting to allow the cure of the belt 20 and the hooks 21. The inner cam surfaces 65 and 66 therefore have semicircular sections 79 and 80 connected by two sliding surfaces 81 and diametrically opposed (FIG. 2).

The adjustment plates 60 and 61 for shifting the insert plates 30 are guided by the ends of the insert plates 30 mounted thereon as they move radially inwards and outwards. In Fig. 2, opposing edges 82 of the insert plates 30 are seen in group B. These edges 82 are parallel to each other and with a radius extending through the axis of the fixing pin 31. The edges 82 are in contact with corresponding edges 83 (FIG. 9) of adjacent forming plates 29. For FIG. to allow radial movement of the adjusting shafts 69 of the insert plates 36 of each group A to H, large holes 84 are formed in the forming plates 29.

The continuous web 44 with the cast hooks 21 on it is directed outwardly around the guide rod 85 (FIGS. 1 and 2) and wound on a spool (not shown) or stored otherwise.

During operation, different parts of the device according to the invention must be kept at a certain temperature and for this purpose the device according to the invention is surrounded by a sheet metal cover 86. Next to the guide rod 85 there is a pivot door 87 for product exit. The temperature inside the sheet metal casing 86 'is maintained by a controlled temperature air flow through the four inlets 88 (FIG. 2). Air flows out through the annular opening 89 (FIG. 3) around the circumference of the round member 24.

The hook grooves 33 form the hooks 21,

Claims (13)

P R E D Μ E T 1. A cast plastic article for use as a first member of a divisible switch, the second member comprising a base and a plurality of hairy hooks projecting from the base, the article comprising a plastic band forming the base and a plurality of complementary hooks releasably connectable to the hooks of the first member; extending from the base, characterized in that the complementary hooks (90) have a shaft (91) and a laterally directed hook portion (93) protruding from the shaft (91) for anchoring the hooks (90) of the first member, the hook portion (93) having a first a flat surface (92) disposed in a first plane (921) perpendicular to the base (20) and is disposed on one side of the first plane (921) and a second flat surface (94) disposed in the second half (941) inclined from the first plane 921) and this intersecting, in which they have rounded surfaces. 13, 14 and 15 show altered shapes in which the loop of the hook 21 has a tapered surface 94 at its end. This inclined surface 94 acts as a cam when the hook 21 is pulled out of the hook groove 33. When the hook 21 connecting the fabric 44 (FIG. 2) extends radially outwardly, the fabric 44 being pulled by the surface of the casting wheel 26, this cam causes the hook 21, the hollow cavity 33 ejects into the gap formed by the displacement of the adjacent insert plate 3D, thereby releasing the loop of the hook 21 from the hollow cavity 33. In Figures 13, 14 and 15, the shaft 90 has two straight sides 91 of equal dimensions and a slightly larger third side 92. The shaft 98 has a larger cross section near the belt 20 than at the end of the hook 21, thereby facilitating the filling of the hook groove 33. The third side 92 is in the same plane as the hook portion 93 (FIG. 15). The hook portion 93 is further inclined to the axis of the shaft 90 at a smaller angle than the hooks 21 in the hook grooves 33 (FIG. 8). It will be appreciated that, by the method and apparatus of the present invention, it is possible to produce articles of different shapes other than the hooks 21 shown in FIGS. 13-15. For example, it is possible to continuously produce a plurality of articles which are attached to a common belt subjects. It will further be appreciated that the invention is suitable for the manufacture of various shapes of cast projections formed as pile and associated with a backing web. Such protrusions may, for example, consist of loops forming one part of the joining structure and hooks, or may be hook elements shaped differently than shown above. Accordingly, it is evident that the described embodiment serves only as an example of an embodiment of the invention. BACKGROUND OF THE INVENTION wherein a second planar surface (94) is disposed on an end portion of the hook portion (93) of each hook (90). 2. The article of claim 1, wherein the hook portion (93) of the hook (90) has a curved shape. Product according to claim 2, characterized in that the shaft (91) of each hook (90) has at least two straight sides (91, 92), each of which adjoins in the hook part (93) of the hook (90) a section of the collapsible straight lines. Product according to claim 3, characterized in that the hooks (90) are arranged in straight lines in the first direction and their hook parts (93) are arranged in planes perpendicular to this first direction, wherein the hook parts (93) are each two the rows of hooks (90) of each pair of straight rows of hooks (90) are arranged in a facing position. 5. A method according to any one of Claims 1 to 4, wherein a plurality of casting cavities are formed, said casting cavities are displaced along a closed path, and a plastic material is injected into the casting cavities, characterized in that the plastic material is fed. two separate feed channels from two separate pumps for filling the cavities by extrusion at high pressure, and the support belt is formed by extrusion at low pressure - and the hooks and support belt are joined while the plastic material cools on the casting surface. 6. Apparatus for carrying out the method of item 5, comprising a set of casting plates arranged in a closed path, each having a portion of at least one casting cavity, further comprising an injection mechanism for discharging plastic material into the casting plates and a casting plate drive assembly; in that the casting plates are arranged in at least three groups (A-H) of the forming plates (29) provided on their two parallel surfaces with hook-like grooves (33) and alternating with planar intermediate plates (30), in planes perpendicular to the axis of the main a shaft (22) of the apparatus, wherein the casting plate groups (A-H) are arranged with their narrow lower surfaces on a base surface (32) of a groove (28) of a support wheel (27) attached to the apparatus main shaft (22); The grooves (28) have the shape of a regular polygon, the forming plates (29) are fixed to the support wheel (27) with a pin (31) tightly received in the circular holes (132) of the forming plates (29), the insert plates (30) are provided with circular holes formed with play around the fixing pin (31) of the forming plates (29), each insert plate (30) has a pair of rectangular holes (70) in which are set up adjusting shafts (69) projecting with clearance through circular cutouts (82) in the mold plates - (29); plates (60, 61) arranged adjacent to the support wheel (27) and provided at their ends adjacent to the main shaft (22) with tracking rollers (63, 64) arranged in contact with the cams (24, 241) mounted on the frame ( 86) equipment. Device according to claim 6, characterized in that each adjusting plate (60, 61) has a hydraulic cylinder (71) mounted in a rectangular slot (72), attached to a guide pin (731) inserted in the support wheel (27), wherein the piston rod (74) of the hydraulic cylinder (71) is mounted in the radially outer portion of the adjusting plate (60, 61). Device according to claim 7, characterized in that adjacent portions of the radially outer edges of the forming plates (29) and the insert plates (30) of each pair are rounded to form a cylindrical casting surface (391). Device according to claim 6, characterized in that a tank (36) for molten plastic material is arranged in a fixed position adjacent to the groups (A-H) of the forming plates (29) and the insert plates (30). 10. The apparatus of claim 9, wherein the tank (36) has a first outlet (37) for a first type of plastic material and a second outlet (38) for a second type of plastic material. Apparatus according to Claims 6 to 10, characterized in that the tank (36) has a discharge spout (35), - provided with a cylindrical surface portion (43) forming a gap with respect to the casting surface (391) formed by groups (A-H) plates (29) and liner plates (30), and adjacent the second outlet (38). Device according to claim 6, characterized in that one side wall of the groove (28) of the support wheel (27) is provided at its upper edge with a peripheral recess (40). Apparatus according to one of Claims 6 to 12, characterized in that a cross-member (45) is provided adjacent to the discharge spout (35) and provided at its ends with a roller (49) arranged in contact with the support wheel surface (39). wherein the cross-member (45) is in pressure contact with a cylindrical spring (52) supported by nuts (53) screwed on a rod (51) mounted in the frame (24) of the device.