GB2109741A

GB2109741A - A supporting device for the die carrier of an injection moulding machine

Info

Publication number: GB2109741A
Application number: GB08229315A
Authority: GB
Inventors: Karl Hehl
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-10-14
Filing date: 1982-10-14
Publication date: 1983-06-08
Also published as: CH661473A5; ATA365582A; JPS5872429A; FR2514290A1; AT380825B; GB2109741B; IT1152901B; IT8223683A0; FR2514290B1; NL8203955A

Abstract

Supporting assemblies (17) which support the die carrier (12) of an injection moulding machine are each vertically and laterally adjustable relative thereto by means of a respective horizontal and vertical screw 16, 15 and the assemblies are (17) each captive between the adjacent rail (26) of the machine base (25) and a bearing strut (13) of the die carrier (12). The supporting assemblies are not rigidly connected with the die carrier, and are provided with bearing assemblies (20) on both their legs for engaging the rail (26). A key pin (31) which engages in a slot (35) ensures motion of the assemblies (17) along with the die carrier (12). <IMAGE>

Description

SPECIFICATION A supporting device for the die carrier of an injection moulding machine The present invention relates to a supporting device for the die carrier of a plastics injection moulding machine which is movable along horizontal tie rods by means of a hydraulic driving device, wherein said supporting device has two vertically adjustable supporting assemblies which are supported on horizontal and vertical faces of rails of the machine base by means of displacement elements mounted in the supporting assemblies, said supporting assemblies extending into horizontal and vertical legs, being relatively vertically and laterally adjustable relative to the die carrier by means of horizontal and vertical screws and being connected to the bearings of the die carrier via engaging means in the form of key pins.

In my U.K. Patent Specification 2061 807A (and German Patent Specification 294311 8), a supporting device is disclosed wherein the supporting assemblies are rigidly connected to the die carrier. Such a connection necessitates relatively low manufacturing tolerances. If there are slight dimensional differences, tension may occur in the support system because, on the one hand, the supporting assembly is inclined to be centred on the rolling face of the rail, but, on the other hand, the supporting assembly is rigidly connected to the die carrier. This applies particularly to supporting assemblies with large supporting faces which are desirable in order to reduce the specific pressure on the surface of the rail.

Using this as a basis, the invention seeks to modify a supporting device of the abovementioned type so that, even with conventional manufacturing tolerances, supporting assemblies having supporting faces of any desirable size may be used at uniform specific pressure without tension.

According to the invention, this object is achieved in that the supporting assemblies are each captive as loose structural units between the adjacent rail and a receiver bearing of the die carrier and are exclusively centred on the faces of the rail, the engaging means (key pins) being designed for a movable connection between the supporting assemblies and the receiver bearings.

Hence, the structural pre-requisites also exist where rollers are used as the travel elements or displacement means in the supporting assembly in order to reduce the working load of the engaging means (key pin).

This particularly applies when the rollers are guided in the guide grooves by means of trunnions and are aligned in a roller cassette in a loose and displaceable manner relative to one another.

Further embodiments of the invention are claimed in the sub-claims.

The present invention will be described further, by way of example, with reference to the accompanying drawings, in which:~ Fig. 1 is an end view in partial transverse crosssection of a supporting arrangement as arranged on a corner of a movable die carrier member; Fig. 2 is a side elevation in partial longitudinal cross section of the supporting arrangement of Fig. 1; Figs. 3 and 4 are enlarged details of the supporting arrangement in views corresponding to Figs. 1 and 2, respectively, the cross-sectional view of the vertical roller track of Fig. 3 being taken along lines lIla-lIla of Fig. 4 and the cross section of the horizontal roller track being taken along line IlIb-IlIb of Fig. 4; and Fig. 5 shows a push type die closing unit as part of a plastics injection moulding machine with the supporting arrangement and a verification gauge.

An injection moulding machine is shown in Fig.

5 wherein four horizontal guide tie rods 10 are received, at one end, by a stationary mounting plate 112 of a hydraulic driving device and, at the other end, by a stationary die carrier 111. The mounting plate 112 and the die carrier 111 are mounted on a machine base 25. The piston rod 118 of a drive cylinder 1 i 3 is attached to the die carrier 12 which is supported on a pair of rails 26 by means of two vertically adjustable supporting assemblies 17. Each supporting assembly 17 extends into a horizontal leg portion 17a and a vertical leg portion 1 7b. The supporting assemblies are vertically and laterally adjustable relative to the die carrier and a receiver bearing in the form of an inclined strut 13 by means of horizontal and vertical adjustment screws 15 and 1 6.A vertical threaded screw 1 5 is in threaded engagement with each horizontal leg portion 13a of strut 13 and is secured there, in the position actually set, by a threaded counternut 15a.

Horizontal adjustment screw 16 is in engagement with each vertical leg portion 13b of strut 1 3 and is secured there, in the set position, by a threaded counternut 16a. The load of the die carrier 12 is almost exclusively transferred to the supporting assembly 17 via the vertical threaded belt 1 5. If substantially horizontal force pulses act upon the die carrier 12 and they are substantially perpendicular to the rolling direction a, the resultant pressures are transferred to the supporting assemblies 17 via the vertical threaded bolts 16. These force pulses may originate, for example, from additional means and the like which act laterally upon the die carrier 12 or upon the injection moulding die respectively.

The supporting assemblies 17 are each captive between the adjacent rail 26 and the associated strut 13 of the die carrier 12 and are exclusively centred on the rolling faces of this rail 26. In consequence, the vertical adjustment and the lateral adjustment (of the supporting assemblies 17) are possible with full, relative mobility between the supporting assemblies 17 and the bearing struts 13 without the centering operation on the rolling faces of the strips 27 of the rails 26 being adversely affected. This relative mobility between the supporting assemblies 17 and the associated bearing struts 13 is not eliminated by key pin 31 of the bearing struts 13 which cause the supporting assemblies 17 to be carried along in the rolling direction during movement of the die carrier 12.For this purpose, the key pin 31 extends with a slightly conically tapered engagement end 31 b, into a gap 35 formed in the supporting assembly 17, so that a kind of ball joint is formed. The mobility of the supporting assembly 17 in a plane which is at right angles to the direction of travel a causes the engagement end 31 b to terminate some distance from an arcuate base of the gap 35. Mobility in a direction which is perpendicular or at an angle to this plane is ensured because the engagement end 31 b merely abuts, for engagement purposes, against the flanks of the supporting assembly 17, which define the gap 35, in the region of its maximum diameter in the engagement portion.Each supporting assembly 17 and the associated bearing strut 13 have a common plane of symmetry b-b. This plane of symmetry coincides with the diagonal of the die carrier 12 and with the diagonal of rail 26 which has a square crosssection. The key pin 31 is located in the plane of symmetry b-b and is in threaded engagement with a web of the bearing strut 13, which strut extends perpendicularly to this symmetry plane and is secured by a counternut 31 a located in a recess 14 in the bearing strut 13. Adjustment of the screws 15 and 16 leads to an increased or reduced, vertical or horizontal, i.e. lateral, loading of the supporting assemblies 17.An optimum setting occurs when the supporting assemblies are so loaded in vertical and horizontal direction,s and consequently the tie rods 10 are accordingly relieved of load, that these tie rods are relieved to a large extent of both their carrying function and their guide function. In such a case, the tie rods are almost exclusively subjected to axial tension or pressure. In this manner, the guide bearings in the die carrier 12 are saved, and a more accurate guidance for the die carrier is achieved.

Substantially horizontal force pulses, which act from externally upon the die carrier or the injection moulding die, are thereby also introduced into the supporting assemblies without a substantial loading of the tie rods 10 at the time of the occurrence of such pulses. This ensures that in all operating modes of injection moulding machines the pressure of the moulding die halves is correctly positioned and this is especially significant in the manufacture of highly accurately gauged mouldings.The optimum setting is achieved by means of a concentricity or verification gauge generally termed scanning means 50 which can measure the deviation of the supported die carrier 12 from a position which is plane-parallel to the stationary die carrier 111 and is concentric with the central axis d-d. The scanning means 50 is centered in centering aperture 45, which is formed in the stationary die 111, by means of a moulded part 47 which accommodates a ball-mounted holder 48. A tapered pick-up shaft 50a is located centrally on the holder 48 and carries a dial gauge 50b. An indicator slide 50c is disposed at the front end of the housing of the dial gauge, and an indicator head 50d is displaceably mounted in the slide 50c.A pivotable measuring sensor 50e of the indicator head 50d is selectively attachable to the inner surface of the centering aperture 51 formed in the movable die carrier 12 (dotted line) or attachable to the die carrier face of the die carrier 12 for scanning purposes. In the former case, the concentric position is measured and, in the latter case, the plane-parallelism is measured. During setting, the die carrier 12 is loaded with a weight which corresponds to an average moulding die load.

Injection moulding machines are known (German Auslegeschrift No. 2 459 025) in which the plates of the injection moulding die itself are guided on the tie bars 10 and, in consequence, no die carrier exists. In such injection moulding machines, the movable moulding die half is itself supported in the manner according to the invention.

The relative mobility betweent he supporting assemblies 17 and the associated bearing struts 13 also permits the loads and force pulses from the supporting assemblies 17 to be introduced into the rails 26 via a plurality of relatively long and simultaneously loaded bearing rollers 20, and this results in the specific pressures on the surfaces of the strips 27 of the rail 26 being reduced which is highly desirable. In particular, it is possible to align the rollers 20 in grooves 21 in a loose manner, i.e. in a displaceable manner relative to one another, and, in consequence, to accommodate a relatively large number of simultaneously loaded rollers 20 in a linear portion of the grooves.The unrestricted and exclusive centering on the travel rail 26 is advantageous, in such a case, for a parallel movement of the rollers which are loosely adjacent one another and which rotate in opposite directions.

The rollers 20 of each leg portion 1 7a, 1 7b are accommodated in a roller track cassette R. The roller track cassette R is formed by an elongate track core 18 of rectangular cross-section and two track covers 19 which abut against the core 18 on either side in a form-fitting manner. The rollers 20 are guided in the grooves 21 of the cassette covers 1 9 by means of trunnions 20a. The rollers 20 are supported in the linear guide portion facing the rail 26 on the plane underneath side of the cassette core. Each roller cassette is insertable in a recess, extending in rolling direction a, of the associated leg 17a, or 1 7b respectively, of the supporting assembly 17 formed by a solid moulded part. The roller cassettes are secured in the supporting assembly 17 by means of screws 28 which extend through the cassette core via bores 30. The inside width of the bores 30 is greater than the diameter of the screw 28. The cassette covers 19 engage in a form-fitting manner in the bores 30 of the cassette core 18 by means of annular centering flanges 19b.

The cassette covers 19 are formed by deepdrawn die-cut parts made of sheet steel. At each of the two front ends of the roller cassette R, the linear portion, with the loaded rollers 20, extends, in an arcuate manner, into a parallel, linear guide portion of the groove 21 which is located a greater distance from the adjacent longitudinal edge 19d (Figure 4) than the portion at the rail end is from the adjacent longitudinal edge 19c. The rollers, which roll without pressure on the upper end of the core 18, are therefore located entirely within the roller cassette R. The supporting assembly 17 rests, therefore, on the longitudinal edges 17d.

The stamped guide passage 19a is defined in each of the linear portions by a flange 19a of the respective cassette cover 19 and is formed by stamped-in grooves in the arcuate portions.

The roller cassette R is covered on the two front ends by means of plastics panels 22. The panels 22 each rest on the rolling strip 27 of the rail 26 by means of a wiper seal 23. Conically thickened edges 22a of the plastics panels 22 engage, with tepering on three sides, in grooves in the supporting assembly. The plastics panels 22 are reinforced by ribs 22which abut against the tunnel walls of the supporting assembly 17. The roller cassette R is enclosed by a resilient endless wiper seal or strip 23 with wiper lips 23a which rest on the strip 27. The sealing strip is firmly clamped between the cassette covers 19 and the adjacent walls of the supporting assembly 17. The sealing strip 23 is also secured to an angled bracket 22d of each plastics panel 22.

Because of a simultaneous vertical and horizontal support, the supporting device is also not affected if the machine base is inaccurately mounted, i.e. the mounting deviates from an exactly horizontal installation plane. The mounting is therefore simplified, and this also applies to the assembly if the die closure unit is to be mounted on the machine base from above merely by means of a lifting apparatus, for example, in which case the vertical and horizontal screws 15 and 16 of the bearing struts 13 of the die carrier ensure automatic centering without necessitating a securing means between the die closure unit and the machine base.

Claims

1. A supporting device for the die carrier of a plastics injection moulding machine which is movable along horizontal tie rods by means of a hydraulic driving device, which supporting device has two vertically adjustable supporting assemblies which are supported on horizontal and vertical faces of rails of the machine base by means of displacement elements mounted in the supporting assemblies, said supporting assemblies having horizontal leg portions (17a) and vertical leg portions (17b), being relatively vertically and laterally adjustable relative to the die carrier (12) and being connected to the receiver bearings (13) of the die carrier via engaging means, characterised in that the supporting assemblies (17) are each captive as movable structural units between the adjacent rail (26) and a bearing (13) of the die carrier (12) and are exclusively centred on the faces of the rail (26), the engaging means (key pins 31) being adapted for a movable connection between the supporting assemblies (17) and the bearings (13).

2. A supporting device as claimed in claim 1, in which the supporting assembly (17) and the bearing (13) of the die carrier (12) have a common plane of symmetry (b-b).

3. A supporting device as claimed in claim 2, in which the plane of symmetry (b~b) coincides with the diagonal of the die carrier (12) and the diagonal of the rail (26) which has a square crosssection.

4. A supporting device as claimed in any of claims 1 to 4, in which a key pin (31) of the bearing (13) extends into a gap (35) in the supporting assembly (17).

5. A supporting device as claimed in claims 2 to 4, in which the key pin (31) is located in the plane of symmetry (b-b) and has a conically tapered engagement end (31 b).

6. A supporting device as claimed in any of claims 1 to 5, in which, in each leg portion (17a and 1 7b) of each supporting assembly (17), a plurality of rollers (20) are simultaneously capable of being loaded in a linear portion of the guide passage (21).

7. A supporting device as claimed in claim 6, in which the rollers (20) of the two leg portions (17a, 1 7b) are aligned in a roller cassette (R) in a loose and displaceable manner relative to one another, which rollers (20) are guided by means of trunnions (20a) in grooves (21).

8. A supporting device as claimed in claim 6 or 7, in which the roller cassette (R) is formed by a cassette core (18) of rectangular cross-section and two cassette covers (19) which abut against the cassette core (18) on either side in a formfitting manner.

9. A supporting device as claimed in any of claims 6 to 8, in which the roller cassette (R) is insertabie in a recess of the supporting assembly (17) and is secured in the supporting assembly (17) by means of screws (28) which extend through the cassette track core (18) via bores (30), the inside width of the bores (30) being greater than the diameter of the screws (28), and the cassette covers (19) engaging in a form-fitting manner in the bores (30) by means of annular flanges (19b).

10. A supporting device as claimed in any of claims 1 to 9, in which a scanning means (50) is provided for verifying any deviation of the movable die carrier (12) from a position which is plane-parallel to the stationary die carrier (111) and concentric with the centre axis (d-d), the scanning means (50) being centred on the stationary die carrier (111) and being rotatably mounted thereon, and a measuring sensor (50e) of said scanning means (50) abutting selectively either against an inner surface of a centering aperture (51) formed in the movable die carrier (12) or against the clamping face of the movable die carrier (12) for scanning purposes.

11. A supporting device substantially as herein described with reference to and as illustrated in the accompanying drawings.