DE2345311A1 - Die core shift mechanism - for a double parison extrusion head - Google Patents

Abstract

Double parison extrusion die head, for use in a vertical wheel type blow moulding machine having circumferentially arranged moulds with fixed inner mould members and radially movable outer mould members guided to pass over and around the die head and then moved to cooperate with the fixed mould member and clamp about the extruded parison, has movable core members in each extrusion die which are simultaneously moved by a crank arrangement from a rotationally movable member the drive to which is provided at a point equally spaced between the points of attachment of the cranks. Pref. the drive is coupled to the movable member by a keyed shaft passing concentrically through the movable member from one end.

Description

DR. BERG DIPL.-ING. STAPF DIPL.-ING. SCHWABE DR. DR. SANDMAIR

PATENT LAWYERS

8 MÜNCHEN 86, POSTFACH 86 02 45 tO4üJ I |

Lawyer file Zk 358 September 7, 1973

Monsanto Company St. Louis, Missouri / ÜSA

Twin injection head in twin hollow body blow molding machines.

The invention relates to twin spray heads and an actuating mechanism for the actuation of the spray mandrels of identical outlet openings for hose shapes, controlled by an individual programming device, d. i _o the hose section emerging from an injection head, which is introduced into a blow mold and there is inflated to form a hollow body. The invention relates

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15-71-L310 509812/0543

Φ (08t1) 98 82 72 8 Munich 80, MauerkircherstraBe 45 Banks: Bayerische Vereinsbank Munich 453100

<089> 98 70 43 Telegrams: BERGSTAPFPATENT Munich Hypo-Bank Munich 389 2623

3310 TELEX: 05 24 560 BERG d Postscheck Munich 653 43 -808

specially designed for a twin spray head for a vertical wheel B la sraas chine, which characteristically radially displaceable Mold halves for receiving hose preforms having at a loading station.

Wheel blow molding machines for the production of z _o B ₀ plastic bottles with large volumes are known. They have a number of molding units which are arranged distributed around a circumferential hub and which extend from the hub as "spokes" of a wheel. This type of machine, such as is essentially known from US Pat. No. 2,784,452, issued March 12, 1957, operates in such a way that each of the radially arranged molding units continuously on a circular path forwards past an extrusion head into a loading position where the mold halves are closed around a tube molding which is extruded through the die head, up to. a blowing station, where the now enclosed tubular molding is inflated into the shape of the cavity of the closed mold. The molds are then moved to an ejection station where the mold halves are opened and the molded body is ejected. The radially separated mold halves are then moved forward j until they re-enter the loading station ^

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The mold units each have a locking mold half, which is fixed in the vicinity of the rotating hub, and a radially movable mold half, which for an inward movement to close and an outward movement to open the mold under the control of cam rollers is mounted, which are connected to the movable mold half and on a locking cam guide to run.

At the loading station, an extrusion head for tubular moldings is supported at the end of a connection channel to the extruder, which is located near the wheel Mold cavity parts is arranged when the mold halves are moved together during loading. The mold halves of a typical machine are closed when the mold in question is in a position which corresponds to the position of the small hand of a clock, when it is 3 o'clock ^ -clock position ¹ ). In the 1 o'clock position of the mold, the mold halves are most radially apart. When changing from the fully open to the closed position

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a cam control mechanism moves the outer mold half radially inward, so that a tube molding in the completely closed form directly under the die head nozzle is included. The "arc of movement of the inner stationary mold halves" is such that these at walk past the side walls of the spray head facing them without making contact. “The spray head is in proportion close to the surrounding inner mold halves when they are between the 1 o'clock position and 3 o'clock graduation. The outer mold halves are as they move inward through the cam mechanism guided so that they are on the head and the outer side walls of the fixed spray head pass without contact, before the mold halves are completely closed.

It can be seen that the full extent to which the outer mold half has moved radially away from the inner mold half must be, in this type of blow molding machine essentially by the cross-sectional shape of the die head block and in particular determined by the required roughness which is occupied by the actuating elements for the spray mandrels at the upper end of the spray head block will. It is known that such actuating elements are used to change the wall thickness of a tube molding

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along its axial length for the best material distribution in a finished blown product, the injection mandrels cause a change in the wall thickness by adjusting the size of the annular gap and the characteristic dimensions of the exit gap for the tube molding programmed raising and lowering of a mandrel front part at the exit gap.

In the case of a wheel blow molding machine with only one hose extrusion head are actuators of different types for raising and lowering the single spray mandrel used on the head of a spray head without \ a Face value is required for the head space. Fenn, however, is the single hose extrusion head of a wheel blow molding machine is exchanged for a twin spray head and each mold half is provided with a twin cavity, Known actuators for twin spray mandrels are impractical. One of the main drawbacks such actuators consists of an undesirably large head space required, as above Are defined.

In contrast, the invention provides a common actuation mechanism for twin injection mandrels.

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which requires little head space and is controlled by a single programming device, so that the two injection mandrels of a twin pair of exit slits for tubular molded articles are uniformly controlled will. This means that existing single injection head blow molding machines can be converted, as is the design a new orientation for the simultaneous twin blowing of hollow bodies.

In particular, the invention provides a single tilt shaft assembly in conjunction with the actuation of the spaced-apart spray mandrels of a twin spray head, as well as an arrangement through which equal tilting moments are applied to each spray mandrel, with the torque for tilting the tilting shaft via a crank arm at the extreme outer end of the shaft using a single program device is applied outside of the turning path of the wheel.

According to the invention is on a twin spray head with Spray mandrels, which extend upwards beyond the upper spray head wall, one horizontally arranged Hollow shaft section is provided which is rotatable on the spray head to the side of the spray mandrels and on an axis

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is mounted parallel to a vertical plane, the runs through the axes of the spray mandrels. On the hollow shaft are opposite the protruding spray mandrel ends Fixed operating lever arms which engage in these ends so that they by rotation of the hollow shaft a Cause axial movement of the spray mandrels in a vertical direction. Inside the hollow shaft and in the middle between an inner end portion of a drive shaft section is attached to the lever arms and the injection mandrel axles. the The drive shaft extends outward from the hollow shaft to the supported end of the spray head and is mounted in a bearing block on the spray head, beyond the bearings and at the end of the drive shaft a crank arm is attached. The crank arm can be swiveled hinged to a reciprocating control plunger, the movement of which is controlled by a suitable programming control device is controlled.

A drive shaft attached to the inside Rotary movement is in turn transmitted to the hollow shaft at its area arranged centrally between the spray mandrels. The actuating lever arms engaging in each of the spray mandrels are from this central fastening point in the equally spaced so that the for lifting

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and lowering the spray mandrels respectively transmitted forces are the same size and have the same uniform changes result in the wall thickness of the tube blanks extruded at the same time.

In summary, the invention creates one of the actuating forces for uniform actuation of the injection mandrels of a twin injection head of a vertical wheel blow molding machine equalizing mechanism, creating an even change in the wall thickness of a pair is achieved by hose preforms, which at the same time be extruded from the spray head. A single programmer controls the actuation of the actuation mechanism. Spray mandrels extending upward from the twin spray head are passed through Actuated rocker arm, which is attached to a rotatably mounted hollow shaft section of a composite shaft are, which have a drive shaft fastened therein on a centrally arranged at the same distance from the spray mandrel axes Attachment portion is attached. The drive shaft extends from one end of the hollow shaft. A crank arm on the outer end of the drive shaft is pivotably linked to a control plunger, which can be moved in a controlled manner by the single programming device

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is. The composite hollow shaft arrangement causes equal movements of the spray mandrels and requires a minimum of head space for a twin spray head, which means retrofitting an existing single-tube blow molding machine is relieved on a twin spray head.

The special features and advantages of the invention emerge from the following, which go into detail Description of a preferred embodiment, which can be seen from the drawing. In the drawing shows:

Fig. 1 is a partial view of a vertical wheel hollow body blow molding machine at the loading station, where illustrates the closing process of the separable molds with respect to a stationary spray head is,

Figure 2 is a plan view of a twin die head block with the same tilting moments according to the invention transmitting drive shaft arrangement, which is mounted on the spray head and is shown partially in section,

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Fig. 3 is a vertical section along line 3-3 in Fig. 2 through one of the spray chambers for the Edition of the Sctilauchf ormlinge, and the

Fig. 4

and 5 partial views showing the one-piece attachment the driven hollow shaft and the drive shaft of the shaft assembly show.

In Fig. 1 a section is shown in which the loading station a typical wheel blow molding machine schematic, is shown. In this section of the machine the molding units, which respectively are supported on the "spokes" of the vertically arranged, clockwise rotating wheel, by conventional Mechanisms operated by which the Fortnhälften in a position of maximum radial distance be held before they are rotated past a stationary spray head, and closed while moving the extrusion head, the outer mold half is continuously brought inward into a position in which it is located close to the inner fixed mold half, with an extruded hose molding between the mold halves is recorded. As soon as the mold is loaded, the mold halves are used for subsequent blow surgery.

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functions and the like immediately clamped together, as can be seen.

In Fig. 1, the hub 10 of the wheel on a "shown horizontal rotary shaft 12 _β The hub 10 carries a circular plate 14 on which the" spokes "are supported radially of the wheel. Each" spoke ", which denotes in its entirety with 16 is attached in a suitable manner to the circular plate 14 and has, substantially as shown,
a radially oriented support plate 18 with an inner end 20 and an outer end 22, which is outside
the circular plate 14 is arranged. A pair of parallel guide rods 2k are fastened between the ends 20 and 22 and are used to guide a movable outer mold half 2.6 for its radial movement in and out
serve an open and closed position with respect to an inner mold half 28 secured near the hub. A holding block 25 for the outer mold half, to which the outer mold half 26 is fastened in the usual manner, is slidably attached to the parallel guide rods 24. The holding block 25 is located on
inner end of a radially movable assembly which extends outwardly from the block and which served to effect the movements for opening and closing the mold. A return roller 30 for opening the mold is on

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an outer actuating block 32 and cooperates with a fixed cam guide which has a return cam Jk for opening the mold. Inwardly at a distance from the actuating block 32, an inner actuating block 36 connected to it by side webs 35 is arranged, which carries a form-closing roller 38 which cooperates with a fixed closing curve kO . Conventional spacers are attached between the block 36 and the block 25 for setting the correct positions of the outer mold half 26.

As can be seen, the outer return roller 30 engages the fixed return curve 3 ^ to control the opening movement of the mold half 26. The inner closing roller 38 engages the fixed closing curve ko for the inward closing movement of the mold half 26. In the one o'clock position of the wheel spoke in FIG. 1, the mold halves are separated from one another by a maximum distance. In the two o'clock position, the outer mold half 26 has moved inwards towards the closed position due to the engagement of the closing roller Jk on the closing curve ko . In the three o'clock position, the mold halves are closed, and they are loaded with a tube molding in the fully formed mold cavity.

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The wheel hollow body blow molding machine and its operation, such as In brief, it is known and as described above, for example, in US Pat. No. 2,784,452, machines of this general type have been widely used with a single spray head which is in the same relative position was attached, as by the outline of the spray head 42 indicated. The spray head is usually at its upper end, its head with a spray mandrel actuation mechanism equipped, which is controlled by programming devices such that predetermined Changes in the thickness of the extruded tube can be obtained. The spray mandrel is for a vertical one Movement arranged in the spray head and with a mandrel front part at its lower end for setting the flow characteristics at the outlet gap and to the Provided formation of a predetermined hose wall shape by raising and lowering the mandrel front part. That The upper end of the spray mandrel extends from the head wall of the spray head, with the upper end of the spray mandrel an actuating device is operatively connected.

Furthermore, if the relative positions of the outer mold half 26 are in the one o'clock position and the two o'clock position

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can be seen, that the outer Mold half 26 must be moved on an arcuate path, which contactless on the head and passes the lateral outer wall of the stationary spray head. ¥ ¥ if the required head space for one Die head block is small, a cleaner actuation of the outer mold half for a closing movement is made possible. Single spray heads and the mechanisms for actuating one There are few or no single spikes Problematic with regard to the head space, however, if the exit gap for a twin spray head is necessary one behind the other, as shown in Fig. 1, and when both spray mandrels are precise must be actuated at the same time, so that identical twin hose preforms are generated, the conversion of a single extrusion head machine to a twin tube molding production with a minimum of changes to the requirement for an identical and precise actuation of both spray mandrels by one mechanism to effect, which does not require a greater headroom than the one intended for the single spray heads. A device that solves this task and is designed according to the invention, as shown by FIGS. 2 to 5 will now be described.

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The mechanism is shown in plan view in FIG. 2 and is fastened to the upper wall of an extrusion head 42 which extrudes two hose preforms. The drive end of the assembly is shown above in FIG. It can be seen that the structure at this drive end lies outside the rotational path of the Foriri halves of the wheel spokes, as described in connection with FIG Connection piece to an extruder supported, as shown at 44 in Figo 2 schematically. The supply channel of the spray head 42 is a single channel 46 (Fig, 3) · The channel 46 opens into two separated communication channels for feeding of the two nozzle chambers 50, each of which or a ₀ are shown one.

As also shown schematically in FIG. 2, an upwardly angled support arm 52 is provided which lies outside the rotational path of the wheel parts and which extends to the side of the connecting channel arrangement to which it is fixed. A program-controlled drive $ h , which represents the power source for the actuating mechanism, is supported at the outer end of this support arm. The output rod 5 ^ of the drive 54 is arranged horizontally, as shown in FIG. As a source of strength for the

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Actuating mechanism may be a suitable known one Control apparatus can be used, which can move the drive rod back and forth. The in Fig. 2 and 3 is particularly suitable for the output of a single! programming device, which operates in accordance with the apparatus covered by U.S. Patent 3,538,548 dated November 10, 1970. The drive rod 56 is pivotable on hers as shown Outer end at the fork-shaped end 58 of a connecting or crank arm 60 hinged to a drive shaft. The crank arm forms the drive end of the invention Unit as described below.

The twin spray head 42 itself and its parts which form the annular nozzle cavity like the nozzle chamber Form 50 (Fig. 3) is here representative of such a Spray head shown, which has as a characteristic feature vertical spray mandrels 62, the are brought out of his head. It should be noted that the injection mandrels 62 additionally with a Central bore from its head to its lower end can be provided, as is for the supply of air is known under pressure to prevent collapse of the extruded tube blank. A hollow

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mandrel 6h typically supports the injection mandrel 62 for a vertical movement, on the xuiterem end of which a mandrel front part 66 is fitted, which is arranged centrally in the outlet 68. The mandrel front part 66 is raised and lowered relative to the outlet opening 68, whereby the wall thickness of the Sch.lau.chformlings can be changed, as is known. The mouthpiece 70 in which the outlet opening 68 is formed and the fastening means for holding it in place on the underside of the block, as well as the fastening parts of the assembly, indicated in its entirety by the reference numeral 72, to the head of the block, through which the spray mandrel extends do not form an essential part of the invention and are therefore not described further.

From Fig. 2, the relative position of the spray mandrels 62 and 62 * at a distance from one another can be clearly seen, the front part of the mandrel of the spray mandrel 62 ¹ being arranged behind the spray mandrel, viewed in the direction of the drive end of the block. A movable mold half 26 and a stationary mold half 28 are shown spaced apart on opposite sides of the injection mandrels. A twin mold cavity is in the mold half 26 with the

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Reference number 27 is designated. The mold halves are under the spray mandrels 62 and 62 * to feed the Form brought together.

A driven portion of the assembly is rotatably mounted on the top wall of the spray head 42 " The driven section is designed as a hollow shaft 80. The hollow shaft 80 is rotatable through a Mitte1 bearing 82 and stored by repository 84. Every camp is attached as shown in a bearing block, which is bolted to the top wall of the spray head. It it should be noted that the axial center of each injection mandrel is centered between the center bearing 82 and the adjacent repository 84 is arranged. The hollow shaft is in Axialri chining between the end bearings z, B, through a shoulder 86 is held which is formed from an end portion of the hollow shaft with a reduced diameter and abuts against the flanged sleeve of the bearing 84. This is how the hollow shaft is held in place and stored on a horizontal axis that is next to and parallel to a vertical plane is arranged, which runs through the axis lines of the spray mandrels 62 and 62 * and in which these Axis lines lie.

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A drive section, such as the drive shaft 90 of the assembled shaft assembly, is secured within the hollow shaft 80. The drive shaft 90 is fixed to a central section of the hollow shaft 80. This central section is essentially enclosed by the supporting center bearing 32. The hollow shaft 80 also has a reduced inner diameter along its central fastening section, as a result of which a shoulder 91 (FIG. 5) is formed. Thus, the drive shaft 90, which extends axially into the hollow shaft and has an outer diameter for attachment thereto, which slidably fits into the central portion reduced in the inner diameter, is spaced from the inner surface of the hollow shaft wall. The drive shaft 90 extends beyond the end bearing 84 to the outside and runs over an extension 92 of the upper ¥ and. of the spray head block and is mounted in a roller bearing 94 of a bearing block 96 on the extension 92. The bearing 94 supports the drive shaft 90 coaxially with the hollow shaft 80. The crank arm 60, which is pivotally connected to the drive rod 56 as indicated above, is. with the drive shaft 90 outside the bearing_94. firmly connected.

4 and 5 is a preferred method for fixed anchoring of the outer end of the drive shaft 90

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shown in the central fastening portion of the hollow shaft. A plurality of longitudinally extending slots 98 arranged at a distance on the circumference are cut through the circumferential wall of the hollow shaft. When the end portion of the drive shaft 90 is inserted in the correct position, it is welded to the hollow shaft via the slots, with the welding material 99 filling the slots and integrally joining the parts together uniformly and straight. As can be seen from Fig. 2, the axial welding slots of the hollow shaft are held in the middle opposite the spray mandrels 62 and 62 *.

On each side of the center bearing 32 are pairs of spaced apart arranged lever arms are provided as rocker arms 100. The rocker arms are z. B, by welding to the Hollow shaft attached and each rocker arm pair extends laterally one of the spray mandrels, so that it is with their Outer edges around the spray mandrel like a fork. Between the ends of the rocker arms are facing slide shoes 102 for rotation about axially aligned Pins 104 fixed in the rocker arm ends are rotatably mounted, the common horizontal axis of the pins normal to the vertical Axes of the injection mandrels 62 and 62 * extends and the

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Axes that essentially intersects the latter. The sliding blocks 102 have a rectangular shape as shown and are seated in guide grooves 106 formed from horizontal grooves which are cut into the opposite surfaces of a lifting block 108 which is attached to the protruding shafts of the spray mandrels. The lifting blocks are anchored with the associated spray mandrel in the correct position Z ₀ B »by sitting on a shoulder of the spray mandrel and clamping by means of a nut 110 which is screwed against the top of the lifting block 108.

It can be seen from the description of the embodiment of the device shown in the drawing that the head space of a twin spray head block required for the actuation mechanism that controls the spray mandrels can be kept to a minimum, and is comparable to that headspace, which in a similarly equipped single spray head is required. Identical twin Sctilauchformlinge can thus in wheel blow molding machines which is originally designed for the production of a single claw mold, without the basic design of the machine because of an enlarged required head space would have to be changed. The low 'profile of the compound Shaft arrangement as described makes this possible. the

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Forces applied to each of the spray mandrels to raise and lower them are ^{made equal by a "central 11} mounting of the drive shaft 90 in the driven hollow shaft 80. The same amount of movement is applied to the axial centers of the spray mandrels 62 and 62 'by deflection, although the original amount of movement for the actuating force is applied at only one end of the assembled shaft arrangement In this way, a precisely identical vertical movement is achieved for each of the injection mandrels, so that a consequent identity of the hose preforms produced at the same time results.

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Claims (6)

Patent claims: 1.J twin spray head with a pair of spaced apart, vertically movable spray mandrels which protrude from the upper surface of the spray head animal and to change the wall thickness of hose fittings are actuated, which are extruded from the extrusion head, characterized by the on the injection mandrels acting on each other aligning mechanism for actuating the spray mandrels, the mechanism being a shaft assembly composed of several parts with an output member, which is on the top of the spray head is mounted for rotational movement about a "horizontal axis normal to the Injection mandrel axes and laterally close to and parallel to a vertical plane which connecting the axis lines of the spray mandrels to one another and containing them, and with a drive member which has one end fixed to a central fastening area of the output member is connected at equal distances to each of the Spritzdornacnsen, wherein the drive member is attached - 2h - 509812/05 A3 its other end away from the output link extends outward and is mounted for rotational movement about the axis of the drive member, wherein the the other end of the drive member can be actuated for a limited rotary movement of the output member, wherein the output member has tilting elements which extend from it at the same distance from the mitt.igen Attachment area extend and their outer ends with the upper ends of the spray mandrels for their concurrent raising and lowering depending on the tilting movement communicated to the output member are connected. 2. twin spray head and actuating mechanism according to claim 1, characterized in that the output member a hollow shaft section and the drive member is a drive shaft section which extends into the Hollow shaft portion extends and integrally connected to this along the central fastening area is. 3. twin spray head and actuating mechanism according to claim 2, characterized in that the rocker arm elements are formed from lever arms which are attached to the hollow shaft section and whose outer 509812/0543 - 25 - ends have hinged connecting means, those for-the simultaneous raising and lowering the spray mandrels engage on this, wherein the actuating means for actuating the drive member is formed from a crank arm, which extending radially from the outer end of the drive member. 4. Twin spray head and actuation mechanism according to Claim 3 »characterized in that the hollow shaft section in a central bearing, which essentially encloses the central fastening area, and is mounted in end bearings, the outer end of the drive shaft axially on the hollow shaft section aligned in an inwardly arranged in the radial crank arm bearing is rotatably mounted. 5 «twin spray head and actuating mechanism according to claim k , characterized in that the rocker arm elements engaging the spray mandrels each have a pair of lever arms which are attached to the hollow shaft section at a distance from one another and each pair of which faces one another at the outer ends of the lever arms hinged - 26 - 509812/0543 Stranding sliding shoes is with the spray mandrels on their opposite sides with horizontal extending guide grooves are provided in which the sliding blocks slide and engage for identical vertical movements of the spray mandrels when the Lever arms pivoted from the hollow shaft section will, 6. Twin spray head and actuation mechanism according to Claim 1, characterized by the combination with a vertical wheel hollow body blow molding machine for successive blow molding of hollow products with circumferential fasteners for supporting a plurality of radially arranged, circumferential mold units, each mold unit has an inner mold half and a radially movable outer mold half, the spray head stationary its outer end is supported and with its inner end up to the vicinity of the surrounding fastening devices extends, and wherein adjustment means are provided, which are so associated with the mold units are connected that the mold halves are separated radially and an outer mold half on one predetermined circumferential path outside the top and 509812/0543 - 27 - the outer wall of the spray head it, then, in a position in which it is located close to the fixed mold half for loading the mold "and then is guided into a position in which the mold is closed under the extrusion head. 5098 1 2 / 05A3 Blank page