DE102016005623A1 - Apparatus for holding and transporting hollow body preforms during stretch blow molding - Google Patents

Abstract

The invention relates to a device (1) for holding and transporting hollow body preforms (4) during stretch blow molding, with a base body (2) and a holding element (3) mounted on the base body (2), which project into an opening (7) of the hollow body Preform (4) is insertable, wherein the holding element (3) in the radial direction by clamping in the opening (7) of the hollow body preform (4) can be fixed. In order to provide a device (1) of the aforementioned type, which is the case of simple handling for different hollow body preforms (4), it is proposed according to the invention that the holding element (3) has at least two clamping jaws (10), which between a the opening (7) of the hollow body preform (4) releasing and a the opening (7) of the hollow body preform (4) clamping position are radially adjustable.

Description

The invention relates to a device for holding and transporting hollow body preforms during stretch blow molding, with a base body and a holding element mounted on the base body, which can be inserted into an opening of the hollow body preform, the retaining element being clamped in the radial direction in the opening of the hollow body preform. Can be fixed preform.

In practice, for example, in the production of plastic bottles, for example made of PET (polyethylene terephthalate), it is known to produce them from hollow body preforms which are supplied in a stretch blow molding machine to various processing stations, such as a heating device and a blowing device.

The hollow body preforms look like small bottles and have an externally threaded opening which, in stretch blow molding, serves to introduce the gas required to inflate the preheated preform and to fill and empty the bottle in the finished bottle. A major differentiator of various hollow preforms is the diameter of the externally threaded aperture and the axial length of the external thread extending along the aperture.

The transport of the hollow body preforms within the stretch blow molding machine takes place in such a way that a holding element is introduced into the opening of the hollow body preforms whose outer diameter is adapted to the inner diameter of the opening of the hollow body preforms.

In the simplest case, the transport device for the hollow body preforms consists of a movable along a conveyor base body having a holding element as a vertically upwardly facing mandrel whose outer diameter is slightly smaller than the inner diameter of the opening of the transported hollow body preform. This transport device, on which the hollow body preform projects with the opening facing down, is designed only for vertical transport with the opening facing downwards.

From the DE 10 2008 023 701 A1 a device for blow molding containers is known in which the holding element has at least two clamping elements designed as balls, which are spring-loaded radially outwards. By this configuration, the hollow preform is gripped in the opening, so that a transport of the hollow body preform in a horizontal position and in "overhead" position, ie with upward-facing opening, is possible.

A further handling device for preforms is known from DE 20 2012 004 015 A1 known. In this known device, the holding element on several struts, which are resilient in the radial direction. Also in this embodiment, the hollow body preform is gripped in the opening, so that a transport of the hollow body preform in a horizontal position and in "overhead" position, ie with upward-facing opening, is possible.

However, all known transport devices described above have the disadvantage that they are each designed only for the holding and transport of hollow body preforms with a predetermined inner diameter of the opening and / or a predetermined thread length of the external thread.

When changing to a hollow preform with a different inner diameter of the opening or another thread length of the external thread, it is necessary to convert all transport devices of the stretch blow molding machine on the new hollow preform.

In addition to the costly changeover time during which the stretch blow molder is not ready for use, the provision of different sets of transport devices is associated with a high cost.

Based on this, the invention has for its object to provide a device for holding and transporting hollow body preforms during stretch blow molding, which is usable with ease of handling for various hollow body preforms.

The solution to this problem is inventively characterized in that at least two jaws, which are radially adjustable between a the opening of the hollow body preform releasing and the opening of the hollow body preform clamped holding position.

Due to the inventive design of the holding element as a radially adjustable clamping elements, which are releasable between the opening of the hollow body preform and the opening of the hollow body preform clamped position adjustable, it is possible for the first time, a transport device in such a way that they without the change of components for different inner diameter of the openings of hollow body preforms and / or thread lengths is usable.

According to a practical embodiment of the invention, it is proposed that the at least two clamping jaws are radially adjustable via a spreading element. This configuration with a spreading element acting on all clamping jaws is particularly simple in terms of structure and handling.

For actuating the jaws on the expansion element is proposed according to the invention that at each jaw on the side facing the expansion element, a conical contact surface is formed, which is in operative connection with a counter-cone formed on the expansion element. The mutual approach of the mutual conical surfaces causes a displacement of the jaws in the radial direction.

As an alternative to the formation of mutual conical surfaces, it is also possible to form the expansion element as an eccentric disc, which adjusts the clamping jaws in the radial direction during rotation.

With a preferred embodiment of the invention, it is proposed that the expansion element can be actuated via a control rod mounted axially movably in the base body. This purely mechanical actuation of the expansion element and thus also of the clamping jaws constitutes a cost-effective and low-maintenance embodiment of the actuating mechanism.

According to an alternative embodiment of the invention, the spreader or directly the jaws are pneumatically or hydraulically actuated.

Furthermore, it is proposed with the invention that the at least two jaws are biased by spring elements in the opening of the hollow body preform releasing position and that the spreader is biased by a spring element in the direction of the jaws. By this configuration it is ensured that on the one hand during retraction of the expansion element, the jaws are compressed for insertion into the opening of a hollow body preform in its initial position with the smallest radial diameter and on the other hand when advancing the expansion element on the jaws to this safe and stable in the clamping Position can be held in the opening of the respective hollow body preform.

According to a preferred embodiment of the invention, it is proposed that the holding element has four jaws each offset by 90 °, which are adjustable via a common arrow-shaped spreading element, wherein the conical outer sides of the arrow-shaped spreading element form the counter-cone for the conical contact surfaces of the clamping jaws are formed on the base body in the ends of the jaws.

By using four jaws which press against the inner wall of the opening of the hollow body preform, a solid and secure against rotation of the hollow body preform is ensured on the support member.

For actuating the control rod driving the expansion element, the control rod is coupled according to the invention with one end to the expansion element and at the other free end of the control rod a driving element is arranged, via which the control rod can be pulled out of the base body in the axial direction. According to the invention, the entrainment element is operatively connected to a control cam arranged on a transport path such that the control cam presses the entraining element and thus also the control rod in the axial direction away from the main body when the entrainment element starts up against the control cam.

This combination of the driving element mounted on the control rod with the control cam arranged on the transport path ensures that the control rod is pulled out of the base body precisely when the clamping jaws move together, when the retaining element is arranged above the opening of a newly received hollow body preform.

After passing over the control cam, the control rod is released again and pushes the jaws over the expansion element radially outward into the opening of the hollow body preform clamping position.

Finally, it is proposed with the invention that the spring element, via which the expansion element is biased in the direction of the jaws, the control rod coaxially surrounding the base body. This arrangement of the spring element allows a particularly compact design.

Further features and advantages of the invention will become apparent from the accompanying drawings, in which an embodiment of a device according to the invention for Holding and transporting hollow body preforms during stretch blow molding is shown by way of example only, without limiting the invention to this embodiment. In the drawings shows:

1 an exploded perspective view of a device according to the invention for holding and transporting hollow body preforms during stretch blow molding;

2 a longitudinal section through the device according to 1 in the assembled state;

3 a side view of a hollow body molding;

4 an enlarged view of the detail IV according to 2 representing the jaws in the contracted end position;

5 a view according to 4 but presenting the jaws in the pushed apart end position;

6 an uncut plan view of the illustration according to 4 and

7 an uncut plan view of the illustration according to 5 ,

The in the pictures 1 and 2 illustrated holding and transport device 1 consists essentially of a basic body 2 and a retaining element at a free end 3 for receiving a hollow body preform 4 ( 3 ) is arranged.

At the holding element 3 opposite end are on the main body 2 Mounting elements, such as a mounting plate 5 , arranged over which the holding and transporting device 1 can be fixed to a transport system, not shown, a stretch blow molding machine.

The holding and transport device 1 used in the production of plastic bottles, for example made of PET (polyethylene terephthalate), to PET hollow preforms 4 various processing stations a stretch blow molding machine, such as a heater and a blower to supply.

As an alternative to PET, plastic bottles are also produced, for example, from PP (polypropylene) or PS (polystyrene). The handling of the hollow body preforms described below 4 but in any case, regardless of the type of plastic material used.

How out 3 see, see the hollow body preforms 4 like small bottles and have one with an external thread 6 provided opening 7 during stretch blow molding for introducing the to inflate the preheated hollow body preform 4 required gas and in the finished bottle for filling and emptying the bottle is used.

A major differentiator of various hollow preforms 4 is the diameter of the external thread 6 provided opening 7 as well as the axial length of itself along the opening 7 extending external thread 6 ,

To the hollow body preform 4 in the heater to be able to heat evenly, which is imperative for a uniform inflation to the bottle end shape, the hollow body preform 4 exactly in the middle and at the right height on the holding element 3 be arranged. About one on the main body 2 arranged sprocket 8th is the hollow preform 4 in the heating device of the stretch blow molding machine about its longitudinal axis 9 rotatable, allowing a full and uniform heating of the hollow body preform 4 is guaranteed.

In the illustrated embodiment, the holding element 3 of four each offset by 90 ° to each other arranged jaws 10 between one the opening 7 of the hollow body preform 4 releasing position ( 4 and 6 ) and one the opening 7 of the hollow body preform 4 clamped holding position ( 5 and 7 ) are radially adjustable.

As from the pictures 1 . 6 and 7 Obviously, the jaws are 10 radially displaceable in one with grooves 11 provided guide block 12 stored so that the jaws 10 along the grooves 11 are movable.

The radial adjustment of the jaws 10 between the opening 7 of the hollow body preform 4 releasing position and the opening 7 of the hollow body preform 4 Clamping holding position via a common expansion element 13 , including on each jaw 10 at the spreader 13 facing side a conical contact surface 14 is formed, with one on the spreader 13 trained counter cone 15 is in active connection.

The conical outer sides of the arrow-shaped spreading element 13 form the counter-cone 15 for the conical contact surfaces 14 the jaws 10 attached to the body 2 mounted ends of the jaws 10 are formed.

The actuation of the expansion element 13 and thus also the jaws 1 takes place via an axially movable in Grundköper 2 stored control rod 16 that has one end with the spreader 13 is coupled and at the other free end of a driving element 17 is arranged, over which the control rod 16 in the axial direction of the main body 2 is removable.

As further from the pictures 4 and 5 Obviously, the jaws are 10 via spring elements 18 in the opening 7 of the hollow body preform 4 biased releasing position and is the expansion element 13 via a spring element 19 towards the jaws 10 too biased.

A constructed as described above holding and transporting device 1 for hollow body preforms 4 in stretch blow molding works as follows:
To the hollow body preforms 4 Within a stretch blow molding machine to supply different processing station, such as a heater and a blower, the stretch blow molding along the transport path a plurality of successively arranged holding and transport device 1 for transporting the hollow body preforms 4 on.

The loading of the holding and transport devices 1 with the hollow body preforms 4 takes place such that the traveling along the transport path holding and transport devices 1 via another transport system, the hollow body preforms 4 be fed until the holding and transport devices 1 the hollow body preforms 4 take over at a defined transfer point for further transport within the stretch blow molding machine.

At the transfer point a control cam is arranged on the transport route, which with the entrainment element 17 the holding and transport device 1 enters into operative connection. When moving the holding and transport device 1 along the transport path that runs on the holding element 3 far end of the control rod 16 arranged entrainment element 17 on the control cam, that the control cam, the driving element 17 engages underneath and the entrainment element 17 together with the control rod fixed thereto in the axial direction vertically upwards away from the main body 2 the holding and transport device 1 draws.

This movement of the control rod 16 causes that on the entrainment element 17 opposite end of the control rod 16 at the tax bar 16 fixed spreading element 13 against the force of the coaxial on the control rod 16 arranged spring element 19 away from the jaws 10 of the holding element 3 is pulled.

Since now the spreader 13 no more about the molded counter cone 15 with the spring force of the spring element 19 against the cone-shaped contact surfaces 14 the jaws 10 of the holding element 3 presses, the jaws are 10 through the spring elements 18 along the grooves 11 of the guide block 12 pressed inwards until abut each other. This end position of the jaws 10 defined with the outer diameter of the compressed jaws 10 plus a minimum allowance at the same time the smallest to be absorbed inside diameter of the opening 7 a male hollow preform to be picked up 4 ,

The transfer point on the transport route is set up so that the holding and transport device 1 after lifting the driving element 17 through the control cam with the compressed jaws 10 ahead in the opening 7 a hollow body preform 4 is introduced.

In the further process of the holding and transport device 1 along the transport route enters the entrainment element 17 again disengaged from the control cam, causing the control rod 16 by the force of the coaxial on the control rod 16 arranged spring element 19 in the axial direction again in the direction of the main body 2 to be pulled down.

This movement of the control rod 16 now causes that on the driving element 17 opposite end of the control rod 16 at the tax bar 16 fixed spreading element 13 by the force of the coaxial on the control rod 16 arranged spring element 19 on the jaws 10 of the holding element 3 is pressed too.

The spring force of the expansion element 13 in the direction of the jaws 10 of the holding element 3 pressing spring element 19 is sized so that it is greater than the spring force of the spring elements 18 through which the jaws 10 to be compressed inside.

Since now the spreader 13 over the molded counter cone 15 with the spring force of the spring element 19 against the cone-shaped contact surfaces 14 the jaws 10 of the holding element 3 presses, the jaws are 10 against the spring force of the spring elements 18 along the grooves 11 of the guide block 12 pressed outwards until this against the inner edge of the opening 7 the associated hollow body preform 4 start and grip it.

In this position is the hollow body preform 4 firmly and accurately positioned on the holding and transport device 1 arranged so that the hollow body preform 4 the other processing stations of the stretch blow molding machine can be supplied.

The removal of the hollow body preform 4 or the finished bottle from the holding and transport device 1 done either by simple vertical peeling or again by contraction of the jaws 10 on the operation of the control rod 16 stored entrainment element 17 , as before to the transfer point in the assembly of the holding and transport device 1 with the hollow body preforms 4 has been described.

Such designed holding and transport device 1 for hollow body preforms 4 When stretch blow molding is characterized by the fact that this easy handling for different hollow body preforms 4 is usable.

Due to the design of the retaining element 3 radially adjustable clamping jaws 10 between one the opening 7 of the hollow body preform 4 releasing and one opening 7 of the hollow body preform 4 Clamping holding position are adjustable, it is possible for the first time, a holding and transport device 1 so that they without the change of components for different inner diameter of the openings 7 of hollow body preforms 4 and / or thread lengths is usable.

LIST OF REFERENCE NUMBERS

1

Holding and transport device

2

body

3

retaining element

4

Hollow preform

5

mounting plate

6

external thread

7

opening

8th

sprocket

9

longitudinal axis

10

jaw

11

groove

12

guide block

13

spreader

14

conical contact surface

15

counter-cone

16

control rod

17

driving element

18

spring element

19

spring element

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008023701 A1 [0006]
• DE 202012004015 A1 [0007]

Claims (10)

Device for holding and transporting hollow body preforms ( 4 ) in stretch blow molding, with a base body ( 2 ) and one on the main body ( 2 ) mounted retaining element ( 3 ) placed in an opening ( 7 ) of the hollow body preform ( 4 ) is insertable, wherein the retaining element ( 3 ) in the radial direction in the opening ( 7 ) of the hollow body preform ( 4 ), characterized in that the retaining element ( 3 ) at least two jaws ( 10 ), which between one the opening ( 7 ) of the hollow body preform ( 4 ) and one opening ( 7 ) of the hollow body preform ( 4 ) Clamping holding position are radially adjustable. Device according to claim 1, characterized in that the at least two clamping jaws ( 10 ) via a spreading element ( 13 ) are radially adjustable. Device according to claim 2, characterized in that on each jaw ( 10 ) at the spreading element ( 13 ) facing side a conical contact surface ( 14 ) is formed, which with one on the expansion element ( 13 ) formed countercone ( 15 ) is in operative connection. Device according to claim 3, characterized in that the spreading element ( 13 ) via an axially movable in the basic body ( 2 ) mounted control rod ( 16 ) is operable. Device according to one of claims 1 to 4, characterized in that the at least two clamping jaws ( 10 ) via spring elements ( 18 ) into which the opening ( 7 ) of the hollow body preform ( 4 ) releasing position are biased. Apparatus according to claim 5, characterized in that the expansion element ( 13 ) via a spring element ( 19 ) in the direction of the jaws ( 10 ) is too biased. Device according to one of claims 3 to 6, characterized in that the retaining element ( 3 ) four each offset by 90 ° to each other arranged jaws ( 10 ), which via a common arrow-shaped expansion element ( 13 ) are adjustable, wherein the conical outer sides of the arrow-shaped expansion element ( 13 ) the counter cone ( 15 ) for the conical bearing surfaces ( 14 ) of the jaws ( 10 ), which correspond to those in the main body ( 2 ) mounted ends of the jaws ( 10 ) are formed. Device according to one of claims 4 to 7, characterized in that the control rod ( 16 ) with one end with the expansion element ( 13 ) and at the other free end of the control rod ( 16 ) a driving element ( 17 ) is arranged, via which the control rod ( 16 ) in the axial direction from the main body ( 2 ) is removable. Apparatus according to claim 8, characterized in that the entrainment element ( 17 ) is in operative connection with a control cam arranged on a transport path in such a way that the control cam is in operative connection when the carrier element ( 17 ) against the control cam the driving element ( 17 ) and thus also the control rod ( 16 ) in the axial direction away from the main body ( 2 ) presses. Device according to one of claims 6 to 9, characterized in that the spring element ( 19 ) over which the expansion element ( 13 ) in the direction of the jaws ( 10 ) is too biased, the control rod ( 16 ) coaxially surrounding in the body ( 2 ) is arranged.

Images