GB2032334A - Installation for producing composite castings - Google Patents

Abstract

Installation for producing composite castings 67 e.g. squirrel cage rotors for electric motors by casting round prefabricated inserts 7 in the casting mould 4, 5 of a pressure casting or injection moulding machine 1. Ancillary devices for feeding the inserts e.g. stacks of laminations 7 to the mould and removing the composite castings 67 from the mould, spraying the moulds with a release agent and stripping the composite castings 67 from the sprue system are provided. In order to increase the productivity of the casting installation, an ancillary device disposed between a feeder-discharge device 24 to 30 and a station for the prefabrication of the inserts 7 located outside the installation, has an automatic separating-transfer station 13, 16, in conveying relationship 10, 12, with the insert prefabrication station. The feeder- discharge device 24 to 30 is further equipped with multiple gripper tongs 24, 26 each for loading and unloading the inserts 7 and composite castings 67 respectively. The multiple gripper tongs are pivoted together into position between the open casting mould sections 4, 5 and removed from there in synchronism with the mould sprayer device 6. <IMAGE>

Description

SPECIFICATION Installation for producing composite castings The present invention relates to an installation for producing composite castings by casting round prefabricated inserts in the mould of a pressure casting or injection moulding machine (e.g. also suitable for the production of conventional castings without inserts) which has ancillary devices associated with it, e.g. for feeding of the inserts and discharge of the composite castings, mould spraying, separation of the composite castings from theirsprue systems and from any auxiliary handling elements.

Such an apparatus is known in which two automatic sliders enter between the mould sections consecutively. One slider places in the mould prefabricated stacks or packs or bundles of stampings for two electric motor rotors at a time. The other slider, in a separate movement phase, discharges the fully cast rotors from the mould. After the discharge of the fully cast rotors and before the insertion of fresh packs of stampings, the mould cavities are wetted with a release agent by an automatic mould spraying device. Consequently with this apparatus, a double period for the to and fro movement of the sliders is required during a casting cycle, these being further separated by the period necessary for the mould spraying. These lost periods therefore affect the productivity of the installation adversely.

A discharge mechanism is also known which has a gripping tongs arranged on a discharger arm which is moved in a polar orbit between the open mould sections. With this mechanism the mould can not only be discharged but also loaded with inserts.

However, here again the machine is subject to the lost periods previously mentioned.

In the production of motors with squirrel cage winding it is known from US-PS 2 248461 and 2795 021 to construct a mould part so that it can slide piston-fashion into the other mould part in order to compensate for height differences of the packs of stampings resulting from production tolerances of the individual stampings. In these known apparatus no venting channels for the evacuation of the mould cavity are provided. The inability for venting the mould cavity occasionally causes gas inclusions in the composite castings.

The present invention has the aim to improve an installation such as initially mentioned in such a way that its productivity is increased and such thaws the casting quality can be improved.

Accordingly, in one of its aspects the invention provides an installation for the production of composite castings incorporating prefabricated inserts, comprising a pressure casting or injection moulding machine which is also suitable for the production of castings devoid of inserts, a feeder-discharge device for feeding inserts to the mould of the machine and for discharge of composite castings from the mould, a mould spray device, a stripper device for stripping the composite castings from their sprue systems and from auxiliary handling elements if present, a separating-transfer station to receive and separate the inserts and for the transfer thereof, the feederdischarge device including a multiple gripper tongs for loading inserts and a multiple gripper tongs for unloading of composite castings into and from the mould respectively, the multiple gripper tongs when both positioned between the open mould sections being vertically lowerable alternately in synchronism with the mould spray device for the latter to spray one of the mould sections.

According to another aspect the invention provides an installation for the production of composite castings incorporating pre-fabricated inserts, comprising a pressure casting or injection moulding machine, loading multiple gripper tongs to co-act in an operative position with a mould section of a multiple mould of the machine to load it with a multiplicity of inserts, unloading multiple gripper tongs to co-act in an operative position with the other mould section of the mould to unload composite castings from it, the multiple gripper tongs being able to occupy respective idle positions offset from their respective operative positions, a mould spray device, and control means for controlling the movement and operation of the multiple gripper tongs and the mould spray device such that both multiple gripper tongs can together be in position between the opened mould sections and that when in such position each multiple gripper tongs can in turn occupy its respective idle position whilst the mould spray device sprays the mould section with which that multiple gripper tongs can co-act and whilst the other multiple gripper tongs is in its operative position in which it can co-act with the other mould section.

According to a further aspect the invention provides a method of producing composite castings incorporating prefabricated inserts which includes the steps of transferring a multiplicity of inserts to a loading multiple gripper tongs; moving the loading tongs and an unloading multiple gripper tongs into position between the opened mould sections of a multiple mould of a pressure casting or injection moulding machine; whilst (a) the unloading tongs is in an inoperative position relative to a first mould section to unload composite castings from it and (b) the loading tongs is in an operative position relative to the other mould section offset from its operative position: spraying that other mould section with release agent; moving the unloading tongs to an inoperative position offset from its operative position, and moving the loading tongs from its inoperative position to its operative position relative to that other mould section to load inserts into it; spraying the first mould section whilst the unloading tongs is in its inoperative position and the loading tongs is in its operative position; moving both multiple gripper tongs out of position from between the mould sections; discharging composite castings from the unloading tongs; and stripping the composite castings from their sprue systems.

An embodiment of the invention for the production of rotor windings for small electric motors (and a modification thereof) will now be described by way of example with reference to the accompanying drawings, wherein: Figure 1 shows a perspective view of a pressure casting installation (from which some components are omitted) including a pressure casting machine and associated ancillary devices; Figure 2 depicts the loading and the unloading tongs of the feeder - discharging device in perspective view; Figure 3 is a side elevation of the loading and unloading tongs according to Figure 2; Figure 4 shows an elevation of the loading and unloading tongs and of the spraying device as seen in the direction of the arrow IV in Figure 1; Figure 5 is a vertical sectional view through the stripping device taken on the plane V-V of Figure 6;; Figure 6 is a vertical sectional view taken on the plane VI-VI of Figure 5; Figure 7 shows an elevation of the movable mould section of the pressure casting machine as seen in the direction of the arrow VII in Figure 1; Figure 8 is a section taken along the plane VIII-VIII of Figure 7; Figure 9 shows in plan a second embodiment of the separating-transfer station with part thereof seen in section along the plane IX-IX of Figure 10; Figure 10 shows an elevation corresponding to Figure 9, and Figure ii shows a similar elevation to Figure 10 on a reduced scale.

Figure 1 shows a pressure metal casting machine 1 with a multiple mould forthe production of squirrel cage rotors for electric motors. Means for feeding the inserts 78 to be incorporated in the squirrel cage rotors by casting are associated with the pressure casting machine. The pressure casting machine 1 has a fixed platen 2 and a movable platen 3, each of which carries one of the two mould halves or sections 4 and 5 of the casting mould. When the mould is open the mould surfaces are wetted with a release agent by means of a mould spraying device 6. The inserts to be cast into the squirrel cage rotors are stacks or packs or bundles of laminations or stampings threaded axially on mandrels which constitute handling elements 8. The casting-in of the bundles of stampings 7 is effected in known manner.

A supply means for the bundles of stampings 7 is constituted by a buffer station 9 in the form of a vibrating bin 11 to which the bundles of stampings 7 are fed along a conveying path 10. The bin 11 has a spiral section 12 and executes a circular vibrating movment so that consecutive bundles of stampings 7 stored therein travel up on the spiral section 12 to a separating device 13 at the end ofthe spiral section 12. The separating device 13 has two pneumatic cylinder and piston units 14which engage alternate liy with their free piston rod ends into the spiral section 12 and thereby interrupt the feed of the bundles of stampings 7 in the manner of lock gates.

The leading bundle of stampings 7 in each case is thereby separated from the following one and is transferred onto a conveyor belt 15 of a transfer device 16. The separating device 13 permits four bundles of stampings 7 at a time to arrive on the conveyor belt 15. When four bundles of stampings 7 are on the conveyor belt 15, the latter is "full" and the separating device 13 blocks the feed of further stamping bundles 7. The leading stamping bundle 7 is moved by the conveyor belt 15 against a stop surface 17, with which it remains in contact whilst the conveyor belt 15 travels onwards. Three pneumatic cylinder and piston units 18 are arranged along the conveyor belt 15, the piston rods of which in one end position reach across the conveyor belt 15 and in the other end position are retracted out of the region of the conveyor belt 15.As soon as the leading stamping bundle 7 is in contact with the stop surface 17, the next cylinder and piston unit 18 slides its piston rod across the conveyor belt 15, so that it serves as a stop for the next stamping bundle 7. As soon as the next stamping bundle 7 is in contact with the first piston rod, the second cylinder and piston unit 18 slides its piston rod across the conveyor belt 15 until the third stamping bundle is in contact with it. Then the third cylinder and piston unit slides its piston rod across the conveyor belt 15 as a stop.

When all the stamping bundles 7 present on the conveyor belt 15 are in contact with the associated piston rod or the stop surface 17, they are uniformly spaced from each other. They are kept in linear alignment by lateral guideways 19. The conveyor belt 15 is mounted in bearings 20 fast with the lateral guideways 19. The lateral guideways 19 in turn are connected fast with each other by way of the end wall constituting the stop surface 17 and are pivotable together with the conveyor belt 15 between two end positions about an axis 21 in a bearing block 22.

A cylinder and piston unit 23 is provided in the bearing block 22 as a pivotal drive. The lateral guideways 19 with the conveyor belt 15 are pivotable out of the end position shown in the drawing to a vertical position.

The feeder device includes a loading tongs 24 which is mounted on a pivoting mechanism 25. The loading tongs 24 is pivotable by the pivoting mechanism 25 between its end position shown in Figure 1 on the one hand and a vertical end position on the other hand. In the first end position the loading tongs 24 is positioned between the two mould sections 4 and 5. In the second end position it is located opposite the conveyor belt 15 pivoted into its own vertical end position.

In order to charge the mould section 4 with the stamping bundles 7, the loading tongs 24 is pivoted by means of the pivoting mechanism 25 out of the first end position outwards into the second vertical end position. The lateral guideways 19 with the conveyor belt 15 are then pivoted into the vertical end position, whilst the mandrels 8 of the stamping bundles 7 lying on the conveyor belt 15 protrude between the clamping jaws of the loading tongs 24.

The loading tongs 24 is then closed and the lateral guideways 19 with the conveyor belt 15 are pivoted back into the horizontal position. Then the loading tongs 24 is lowered by the pivoting mechanism 25 into the first end position between the open mould sections 4 and 5, from which the stamping bundles 7 are inserted into the mould section 4 in the manner described below.

After the stamping bundles 7 have been cast-in, the mould is opened again, i.e., the mould sections 4 and 5 are separated into the position shown in Figure 1. The finished cast rotors 67 with their sprue system 90 then remain adhering in the movable mould section 5. In orderto discharge them, the discharge device includes an unloading tongs 26 which is movable simultaneously with the loading tongs 24 and which in its first end position shown in Figure 1 is located opposite the rotors 67. The unloading tongs 26 removes the finished rotors 67 from the mould section 5 in the manner described below and is pivoted by means of the pivoting mechanism 25 into the second vertical end position.

In this second end position the discharging tongs 26 is pivotable, about an axis 27 provided on the pivoting mechanism 25, into the horizontal position in which it transfers the rotors 67 to a stripping station 28 described in detail below. In this station the sprue system 90 still firmly attached to the rotors 67 is trimmed off.

The mode of operation of the two tongs 24 and 26 is described in detail below with reference to Figure 2. The pivoting mechanism 25 is a known construction which has for years been distributed commercially by the applicant company under the trademark "Pickmat". The two tongs 24 and 26 are mounted on the head of a pivot arm which is pivotable between the mould sections 4,5 by means of the pivoting mechanism 25.

A cylinder and piston unit 30 is mounted in the pivoting mechanism 25 as pivotal drive for the head of the pivot arm. When the piston rod of the cylinder and piston unit 30 is extended, the head of the pivot arm pivots out of the position shown in Figures 1 and 2 through 90 about the axis 27 and is pivoted back when the piston rod is retracted. The head of the pivot arm has two parallel guide tracks 31 and 32 of undercut or dovetail-shape cross-section, in each of which a U-shaped carriage 33 or 34 is mounted for sliding movement in a direction transverse to the longitudinal extension of the pivot arm 29. The carriage 33 is mounted in the associated guide track 31 slidably by means of a cylinder and piston unit 35, and the carriage 34 in the associated guide track 32 slidably by means of a cylinder and piston unit 36.

Guide rods 37 and 38, which are oriented transverseliy to the guide tracks 31 and 32 are fixed to the arms of the carriages 33 and 34 respectively. A bearing block 39 or 40 is mounted slidably on each of the guide rods 37 and 38, whilst a drive 41 or 42 for the sliding movement is provided on each bearing block 39,40. The loading tongs 24 is fixed to the bearing block 39 and the unloading tongs 26 to the bearing block 40. The tongs 24 and 26 can thus be slid to and fro between two end positions in each of two directions at right angles to each other, namely the direction of the guide tracks 31 and 32 and the direction of the guide rods 37 and 38.

The tongs 24 and 26 are only illustrated schematically in Figures 1 and 2. Their construction is shown in detail in Figure 3. Since both tongs 24 and 26 are of identical construction, only the loading tongs 24 is described in Figure 3. The loading tongs 24 has two clamping jaws 43 and 44, each of which has four recesses 45 or 46 to accommodate a mandrel 8. The mutually facing recesses 45 and 46 grip around the mandrel 8 of a stamping bundle 7. The two clamping jaws 43 and 44 are mounted slidably towards and away from each other on a bolt 47, whilst helical springs 48' and 48' mounted near the ends of the clamp jaws 43 and 44 urge them apart. The bolt 47 is secured to a support profile 48 which in turn is fixed to a cylinder housing 49. Each of the clamping jaws 43 and 44 has external wedge surfaces 50 which co-operate with wedges 51 for opening and closing the loading tongs.The clamping jaws 43, 44 are disposed in a frame 52 likewise secured to the support profile 48, upon which a U-shaped fork 53 is mounted for longitudinal sliding. The wedges 51 are secured to the fork 53 by means of straps 54. To the bridge 55 of the fork 53 there is fixed the free end of a piston rod 56 which is secured to a double acting piston 57 mounted in the cylinder housing 49. The piston 57 can be loaded by pressure medium on both sides through connections 58 in order to slide the fork 53 to and fro on the frame 52. When the piston 57 is moved to the left in the cylinder housing 49, the wedge elements 51 urge the clamping jaws 43 and 44 towards each other against the action of the springs 48' and 49', so that the mandrels 8 located between them are clamped.In order to release the mandrels 8 the piston 57 is slid to the right, whereby the wedge elements 51 relieve the wedge surfaces 50 and the springs 48' and 49' act to separate the clamping jaws 43 and 44.

For handling stamping bundles 7 without any mandrels 8, but which have an axial bore, the tongs 24 and 26 may be provided with transversely projecting beak-like projections instead of the recesses 45 and 46. In other respects the tongs can then be of identical construction. Only the piston 57 requires to be loaded with the pressure medium in the opposite sense in order to grip and release the stamping bundles 7.

As Figure 4 shows, the mould spraying device 6 includes a bracket 59 secured to the movable mould section 5, to which the cylinder of a cylinder and piston unit 60 is attached. Its piston rod 61 is horizontally slidable to and fro in the direction of the double arrow shown and carries at its free end a cylinder and piston unit 62. The piston rod 63 of this cylinder and piston unit 62, which is movable vertically up and down (in the direction of the double arrow shown), carries at its lower end a beam 64 on which four nozzles 65 or 66 for spraying a release agent are fixed facing each of the four mould cavities in the mould sections 4 and 5 respectively. The release agent is fed under pressure from a release agent tank to the nozzles 65 and 66 through hoses not shown.

Before the tongs 24 and 26 are pivoted by the pivoting mechanism 25 into the first end position between the mould sections 4 and 5, the piston rod 61 is retracted and the piston rod 63 is raised, so that the mould spraying device 6 is located outside the pivoting range of the tongs 24 and 26. At the commencement of the pivotal movement of the tongs 24 and 26 the loading tongs 24 has accepted from the belt 15 four stamping bundles 7, the mandrels 8 of which are clamped between the clamping jaws 43,44. In the first end position the unloading tongs 26 is slid upwards in the guideways 32 by the cylinder and piston unit 36 into the one end position in which it is opposite the finished cast rotors 67. Meanwhile the loading tongs 24 remains in the lower end position shown in Figure 4 and thus leaves the space clear for the spraying of the mould cavities in the first mould section 4.Then the unloading tongs 26 is moved by the drive 42, with open clamping jaws 43,44, along the guide rods 38 towards the rotors 67 until the free ends of the mandrels 8 are located between the clamping jaws 43, 44. Simultaneously the piston rod 61 is extended and the piston rod 63 is lowered so that the mould spraying device 6 occupies the service position shown in Figure4. When the mould spraying device 6 has reached this service position, the fixed mould section 4 is sprayed with the release agent through the nozzles 65.

Then the unloading tongs 26 is moved along the guide rods 38, towards the right in Figure 4, into the other end position remote from the movable mould section 5, whereby, aided by the ejectors to be described below, it removes the rotors 67 together with the sprue system from the movable mould section 5. The unloading tongs 26 then slides downwards along the guide track 32 into the other end position, in which it lies outside the range of action of the nozzles 66 (cp. Figure 4). The movable mould section 5 is now sprayed with the release agent through the nozzles 66.

After the fixed mould section 4 has been wetted i.e., after the supply of release agent to the nozzles 65 has been switched off, the loading tongs 24 is moved along the guide track 31 into the upper end position and then to the right (in Figure 4) in order to slide the stamping bundles 7 with the mandrels 8 into the fixed mould section 4. When the stamping bundles 7 are located in the mould section 4, the clamping jaws 43,44 of the loading tongs are opened and the latter is moved along the guide rods 37 to the left (Figure 4). After the wetting of the movable mould section 5 by the nozzles 66, the piston rods 61 and 63 are retracted and moved upwards respectively and the mould spraying device 6 is thus removed out of the pivotal range of the tongs 24 and 26.When the pivotal range of the tongs 24 and 26 is clear, they are pivoted back into the vertical end position by means of the pivoting mechanism 25. When this end position has been reached and the conveyor belt 15 with four following stamping bundles 7 likewise occupies its vertical position, the loading tongs 24 with open clamping jaws 43,44 is slid outwards on the guide rods 37 so that the ends of the mandrels 8 of these four following stamping bundles 7 come to lie between the clamping jaws 43,44. The clamping jaws 43,44 are then closed and the loading tongs 24 is slid inwards on the guide rods 37, whilst it carries the four stamping bundles 7 from the conveyor belt 15.

Next, by an actuation of the cylinder and piston unit 30, the head of the pivot arm is rotated through 90 about the axis 27. This causes the rotors 67 retained by the unloading tongs 26 to pass into the working region of the stripper device 28. Simultaneously or previously, the unloading tongs 26 is moved outwards along the guide rods 38. At the end of this sliding movement the clamping jaws 43,44 of the unloading tongs 26 are opened and the rotors 67 are transferred to the stripper device 28. Then, by a fresh actuation of the cylinder and piston unit 30, the head of the pivot arm with the tongs 24 and 26 is pivoted back through 90".

In the meantime the mould sections 4 and 5 have been closed for the next casting operation and reopened. The tongs 24 and 26 can now be pivoted between the mould sections 4 and 5 once more for the purpose of charging and emptying the casting mould in the manner described.

Figures 5 and 6 show the stripper device 28 in detail. It has a main frame 68 constituted by a rectangular frame 69 to which a table board 70 is secured. The table board 70 carries a guide track 71, in which a carriage 72 is mounted which can be driven back and forth by a cylinder and piston unit 73. Four bores 74, the diameter of which corresponds to the outside diameter of the rotors 67, are provided in the longitudinal central axis of the carriage 72. Also secured to the carriage 72 are two centering sleeves 75 which serve to align the carriage 72 with the tools located above it. A bracket 76, to the upper end of which a chute 78 is articulated at 77, is further attached to the carriage 72. The chute 78 is further braced upon the rollers 79 of a rocker 80 which is mounted pivotably on a support 81 fast with the table board 70.

Figure 5 shows the carriage 72 in its inner first end position, in which the piston rod 82 of the cylinder and piston unit 73 is retracted. When the piston rod 82 is extended, it displaces the carriage 72 to the left (Figure 5) until its leading end is approximately flush with the end of the guide track 71. In this outer second end position the carriage 72 is ready for the reception of the finished cast rotors 67, which are transferred to it by the unloading tongs 26. During the extension of the carriage 72, the chute 78 is entrained through the rollers 79, so that it is located at approximately horizontally above the table board 70 (indicated by chain-dotted lines in Figure 5) when the carriage 72 occupies the outer end position.

Four columns 83 are fixed to the table board 70 and carry a yoke plate 84 which is secured to them at their upper ends. A cylinder and piston unit 85, the piston rod 86 of which is slidable up and down vertically, is secured to the yoke plate 84. The piston rod 86 carries at its lower end a support plate 87 which is guided for up and down sliding movement on the columns 83. Secured to the support plate 87 are four tool holder frames or sockets 88, the vertical axis of which is aligned coaxiallywith the bores 74 when the carriage 72 occupies the inner end position shown in Figure 5. Annular punching tools 89, which serve to remove the sprue system 90 from the rotors 67, are inserted into the tool sockets 88. The support plate 87, each tool socket 88 and each punching tool 89 is pierced by a coaxial bore 91, having an associated ejector rod 92 secured to the yoke plate 84 in axial alignment for each punching tool 89.

As Figure 5 shows, each tool socket 88 has at its upper end an annular groove concentric around the bore 91, into which a ring 93 of resilient plastics is inserted. The latter serves for engagement with an annular groove 94 on the mandrel 8 gripped in the rotor 67.

Also secured to the support plate 87 are two centering pins 102 which co-operate with the centering sleeves 75 so that, when the centering pins 102 engage into the centering sleeves 75, the bores 74, the bores 91 and the ejector rods 92 are each axially aligned with a pin 98 insertible from below into the bores 74forthe rotors 67.

Four columns 95, which together retain a support plate 96, are secured to the underside of the table board 70. A pin carrier 97, which has four pins 98 secured to it and projecting vertically upwards, is guided for up and down sliding movement on the columns 95. Also secured to the support plate 96 is a cylinder and piston unit 99, the free piston rod end of which is connected to the pin carrier 97. The pin carrier 97 is moved up and down by the extension and retraction of the piston rod 100. The pins 98 are aligned axially with the bores 91 in the upper support plate 87 and guided in corresponding bores 101 of the table board 70.

In order to accept four rotors 67, the cylinder and piston unit 73 slides the carriage 72 outwards into the second end position, where it remains until the discharging tongs 26 has inserted four rotors 67 into the bores 74. Due to the sprue system 90, the rotors 67 cannot be lowered completely into the bores 74.

In order that the rotors 67 nevertheless remain axially aligned with reference to the bores 74, the carriage 72 has a resilient support 103 which supports the sprue system 90 and maintains the longitudinal axis of the mandrels 8 in the rotors 67 vertically aligned.

After transfer of the rotors 67 to the carriage 72, the piston rod 82 of the cylinder and piston unit 73 is retracted. When the carriage 72 has again reached the inner end position, the cylinder and piston unit 85 is actuated and the support plate 87 with the punching tools 89 is lowered until the latter strike the carriage 72 (Figure 5 right-hand half). Then, first the rotors 67 are lowered completely into the bores 74, whilst the support 103 moves downwards under the pressure of the punching tools 89 until the sprue system 90 rests upon the carriage 72. During the remainder of the downward movement of the punching tools 89 which now follows, the sprue system 90 becomes separated from the rotors 67, whereupon the recoil of the resilient support 103 throws the sprue system 80 into a chute 104 provided on the table 68.In this chute the sprue system 90 slides into a collecting bin (not shown).

Whilst the support plate 87 remains in the lower limit position, the cylinder and piston unit 99 is actuated and the pin carrier 97 with the pins 98 is moved upwards. Because the punching tools 89 urge the rotors 67 downwards, the pins 98 are able to push the mandrels 8, gripped by interference fit, upwards into the bores 90 until they engage with their annular groove 94 in the resilient plastics rings 93. Then, by an appropriate actuation of the cylinder and piston unit 99, the pins 98 are lowered back into the position shown in Figure 5. Next, by a corresponding loading of the cylinder and piston unit 85, the support plate 87 together with the mandrels 8 is raised a short distance (indicated by chain-dotted lines on the right-hand side in Figure 5).As soon as the support plate 87 has reached the intermediate position, the cylinder and piston unit 73 slides the carriage 72 to the left (in Figure 5) into the outer end position. The trimmed rotors 67 stripped of sprues then slide on two rails 105 of the guide track 71 into a chute 106 where the rails 105 terminate, and fall out of the bores 74 onto the chute 106. On the latter they slide into a collecting bin (not shown). The carriage 72 therefore reaches its outer end position in the empty state, i.e. the bores 74 are free again ready to accept fresh rotors 67. During this sliding movement of the carriage 72 into the outer end position, the chute 78 is drawn beneath the punching tools 89.

The support plate 87 is now moved out of the intermediate position into the upper end position in which it is in contact against the yoke plate 84.

During that further upward movement of the support plate 87 the ejector rods 92 penetrate once more into the bores 91 and push the mandrels 8 out of the engagement connection 93, 94, so that they fall out of the bores 91 onto the chute 78. When the carriage 72 has once more been charged with rotors 67, it is moved back with the chute 78 into the inner end position by the cylinder and piston unit 73. The outer end of the chute 78 then descends and the mandrels 8 lying thereon slide into a collecting bin (not shown). As soon as the carriage has reached the first end position shown in Figure 5 the work cycle described is repeated.

Figures 7 and 8 show the moveable mould section 5 of the pressure casting machine 1, which is constructed as a quadruple mould. It has four mould cavity sections 107, into each of which a stamping bundle 7 with a mandrel 8 is inserted. The sprue system 90 is indicated by chain-dotted lines in Figure 7. Since all four mould cavity sections 107 are of identical construction, only one of them is described below. A mould cavity section 107 of the movable mould section 5 further has an annular recess 108 for the production of one short-circuit ring of the sqirrel cage winding on the rotor 67. A corresponding recess 109, for the other short-circuit ring in each case, is provided in the fixed mould section 4, as illustrated in Figure 8.

In a plate 110 of the movable mould section 5 a mould end piece 112 (provided with the recess 108 for the short-circuit ring) is inserted for axial sliding movement in a bore 111. The mould end piece 112, at its end remote from the recess 108, has a wedge surface 113 which abuts against the surface 114 of a counter-wedge 115. The counterwedge 115 is slidable up and down in an intermediate space 116 between the plate 110 and a further plate 117 (the plates 110 and 117 being fast with each other), and is connected to the piston rod 118ofa cylinder and piston unit 119. The height differences which occur in the stamping bundles 7 can be compensated by the co-operation of the counterwedge 115 with the wedge surface 113 of the movable mould end piece 112. The essential here is that such a compensating device 113 to 116, 118, 119 is associated with each mould cavity 107,108,109 so that the height differences of the four stamping bundles 7 can be compensated individually. The further plate 117 forms a cavity 120 which is closed at the back by a plate 121 secured to it. Secured to the plate 121 is a guide member 122 upon which a support plate 123 is guided for reciprocating sliding movement in the direction of the double arrow shown. The movement of the plate 123 is controlled by a cylinder and piston unit, not shown, to the piston rod 124 of which it is connected. The support plate 123 accommodates a total of twenty-four ejector pins 125, six of which are arranged in each mould end piece 112.The ejector pins 125 arranged in a mould end piece 112 are passed through by means of corresponding bores 126 and 127 in the second plate 117, in the mould end piece 112 itself and in the counterwedge 115. In the end position of the support-plate 123 shown in Figure 8, the free ends of the ejector pins 125 extend as far as the recesses 108 for the short-circuit rings.

For the removal of the rotors 67 from the open mould sections 4 and 5, the support plate 123 is slid to the right (Figure 8). This causes the ejector pins 125 to press upon the adjacent one short-circuit ring produced in the recess 108 and push the finished cast rotor 67 out of the mould cavity section 107.

Each of the four mould cavities 107-108- 109 is vented through its movable mould section 112. For this purpose a pin 129 is mounted for axial sliding movement in the plate 110 and is made fast at one end with the movable moult end piece 112 and at its other end with a stop plate 130. The stop plate 130 is in mechanical contact with a connecting part 131 which is mounted slidably bt its tee-shaped head 132 in an undercut or dove-tailed guideway 133.The dovetailed guideway 133 is arranged in a bracket 134 fixed to the movable mould sectionS. The connecting part 131 constitutes on the one hand a cylindrical guide channel 135 for a locking bolt 136 mounted for axial sliding movement therein and on the other hand, with the stop plate 130, a parallel, laterally closed vent channel 137 which issues at the top into a catch chamber 138 open to atmosphere. In the end position of the locking bolt 136 shown in Figure 8, in the latter engages by its lower end into a bore 139 and closes the latter. The bore 139 connects the recess 108 for the one short-circuit ring to the vent channel 137. The locking bolt 136 terminates at the top in a tee-shaped head 140, by which it is mounted slidably in an undercut or dovetail groove 141 in a piston rod 142.The piston rod 142 is secured to a double-acting piston 143 in a cylinder 144.

The venting operates as follows. When the mould sections 4 and 5 are closed for the injection of the casting metal, the piston 143 is loaded with pressure medium on its underside so that it moves into the upper end position and extracts the locking bolt 136 from the bore 139. By this means the entire mould cavity 107 - 108 - 109 is connected to the venting channel 137. Whilst the casting metal is being injected into the mould cavity 107 - 108 - 109 the air displaced by the casting metal escapes through the bore 139 and the venting channel 137 to atmosphere. Just before the casting metal filling the mould cavity reaches the bore 139, the piston 143 is loaded with pressure medium on its upper side and the locking bolt 136 is moved downwards until it closes the bore 139 against emergence of the casting metal.

Each time the mould sections 4 and 5 close, the movable mould end piece 112 adapts itself to the height of the stamping bundle 7 due to the pressure exerted by the counterwedge 115. During this axial displacement of the movable mould end piece 112, the latter displaces the locking bolt 136 inserted in the bore 139, and also by means of the stop plate 130 the entire connecting part 131 together with the guide track 135 for the pin 136, since these components are able to follow the movement with the assistance of the associated dovetail guideways 140, 141 and 132,133.

Figures 9 to 11 show a second embodiment of the separating-transfer station 172, which is constructed as a unit, and an allocating device 173, which replaces the buffer station 9, the separating device 13 and the transfer device 16 according to Figure 1.

In the separating-transfer station 172 the stamping bundles 7 roll on a track 145 with lateral guideways 146 and 146' against a stop 147. The lateral guideway 146' terminates before the stop 147 at a distance which is at least equal to four times the diameter of a stamping bundle 7. Between the end of the lateral guideway 146' and the stop 147, a cantilevered guide surface 147 laterally adjoins the track 145. On the side of the track 145 opposite the guide surface 148, a ram 149 acting towards the stamping bundles 7 is mounted in a stationary bearing 150. The ram 149 has a support plate 151 which is fixed to two guide rods 152 which are mounted for axial sliding movement in the bearing 150. Also fixed to the stationary bearing 150 is a cylinder and piston unit 153, the free piston end of which engages the support plate 151.

The support plate 151 further has four ejectors 154 equally spaced from each other and axially aligned with the four leading stamping bundles 7. The ejectors 154 have a stepped bore 155 in which an axially slidable pin 156 is mounted. The pin 156 is surrounded buy a helical spring 157 which maintains it in the position shown in Figure 9.

The allocating device 173 is arranged on the side of the track 145 opposite the ram 149. It has a magazine 158 which is articulated pivotablyto an axis 159. Two guide rods 160 are secured longitudinally parallel in the magazine 158. Four frame sections 161 are mounted for sliding movement on each of the guide rods 160. Each facing pair of frame sections 161 constitutes a frame 162, between the facing concave surfaces of which the stamping bundles 7 can be slid. Neighbouring frame sections 161 are attached together by screws 163 which simultaneously serve as distance elements. The screws 163 are mounted for axial sliding movement by their cylindrical shank and the screw head in a stepped bore 164, and are firmly screwed by their screw threaded tip in the neighbouring frame section 161. Consequently the frames 162 can be slid towards each other into physical contact, whilst the screws 163 come to stand with their head in proximity of the open end of the stepped bore 164.

The frame sections 161 of the frame 162 remote from the pivot axis 159 are secured to a plate 165 which is acted upon by a piston rod 166 of a cylinder and piston unit 167 fixed to the magazine 158. There is further articulated to the magazine 158 at 168 a piston rod 169 which pivots the magazine 158 between the two end positions shown in Figure 10.

In the lower end position shown in Figure 10 the piston rod 166 of the pressure cylinder 167 actuating the frames is extended so that the frames 162 are in mutual contact and are aligned axially with reference to the four leading stamping bundles 7 on the track 145. In this end position of the magazine 158, the cylinder and piston unit 153 is actuated so that the ram 149 pushes the four leading stamping bundles 7 into the frames 162. During this sliding operation the mandrels 8 impinge by one end into the bores 155 of the ejectors 154 and the pins 156 are pushed back with compression of the helical springs 157. As soon as the stamping bundles 7 are located in the frames 162, the cylinder and piston unit 153 retracts the ram 149.The helical springs 157 which then expand prevent withdrawal of the inserted bundles 7 even if a mandrel 8 should tend to stick in one of the bores 155 due to insufficient play. Then the piston rod 169 is extended and the magazine 158 is pivoted into the upper end position shown in Figure 10. Simultaneously, the piston rod 166 is retracted, whereby the frames 162 are drawn apart. In the upper limit position of the magazine 158, when the frames 162 have been drawn apart, they are located axially opposite the tongs frames of the loading tongs 24 constituted by the recesses 45 and 46.

On the side of the magazine 158 remote from the loading tongs 24, a stationary plate 170 with a wedge surface 171 is arranged in the sliding path of the mandrels 8 overhanging the magazine. Just before the magazine 158 reaches the vertical end position, the corresponding ends of the mandrels 8 reach the wedge surface 171, whereby the stamping bundles 7 are slid slightly out of the frames 162 towards the loading tongs 24. The loading tongs 24 can then in turn grasp the mandrels by a transverse movement and draw the stamping bundles 7 completely out of the frames 162. Then the loading tongs 24 is pivoted between the mould sections 4 and 5, as was described with reference to Figure 1.

Claims (26)

1. Installation for the production of composite castings incorporating prefabricated inserts, com prising a pressure casting or injection moulding machine which is also suitable for the production of castings devoid of inserts, a feeder-discharge device for feeding inserts to the mould of the machine and for discharge of composite castings from the mould, a mould spray device, a stripper device for stripping the composite castings from their sprue systems and from auxiliary handling elements if present, a separ ating-transfer station to receive and separate the inserts and for the transfer thereof, the feeder discharge device including a multiple gripper tongs for loading inserts and a multiple gripper tongs for unloading of composite castings into and from the mould respectively, the multiple grippertongswhen both positioned between the open mould sections being vertically lowerable alternately in synchron ism with the mould spray device for the latter to spray one of the mould sections.

2. Installation forthe production of composite castings incorporating prefabricated inserts, comprising a pressure casting or injection moulding machine, loading multiple gripper tongs to co-act in an operative position with a mould section of a multiple mould ofthe machine to load it with a multiplicity of inserts, unloading multiple gripper tongs to co-act in an operative position with the other mould section of the mould to unload composite castings from it, the multiple gripper tongs being able to occupy respective idle positions offset from their respective'operative positions, a mould spray device, and control means for controlling the movement and operation of the multiple gripper tongs and the mould spray device such that both multiple gripper tongs can together be in a position between the opened mould sections and that when in such position each multiple gripper tongs can occupy its respective idle position whilst the mould spray device sprays the mould section with which that multiple gripper tongs can co-act and whilst the other multiple gripper tongs is in its operative position in which it can co-act with the other mould section.

3. Installation according to claim 2 wherein the control means is adapted to provide for movement of the multiple gripper tongs and spray device in synchronism.

4. Installation according to claim 2 or 3 wherein the pressure casting or injection moulding machine is also suitable for the production of conventional castings devoid of inserts.

5. Installation according to any of claims 2 to 4 wherein the multiple gripper tongs form part of a feeder-discharge device, and further comprising a separating-transfer station for separation of the inserts and the transfer thereof to the multiple gripper tongs for loading into the mould.

6. Installation according to any of claims 2 to 5 further comprising a stripper device for stripping the composite castings from their sprue system.

7. Installation according to claim 6 wherein the stripper device is adapted also to remove from the castings any auxiliary handling elements for the inserts.

8. Instal-lation according to claim 1 or claim 5 wherein the separating-transfer station comprises a separating device and a separate transfer device.

9. Installation according to any of claims 1,5 or 8 wherein the separating-transfer station is preceded by a buffer station connected by a conveyor device to a station for the prefabrication of the inserts.

10. Installation according to any of claims 1,5,8 or 9 wherein. the separating-transfer station includes a separating device having two cylinder and piston assemblies of which the piston rods are arranged to engage alternately in a movement path of the inserts on their way to the separating-transfer station and which form lock gates for the movement of the inserts.

11. Installation according to any of claims 1, 5 or 8 to 10 wherein the separating-transfer station includes a'transfer device having a belt conveyor and a number of compartments which corresponds to the number of composite castings to be produced simultaneously, the length of the compartments being delimited by stops so that the spacing of the inserts corresponds to the arrangement of the mould cavities, the stops being movable into the movement path of the inserts, the transfer device being pivotable by means of a drive between a horizontal position in which itis in operative connection with a separating device of the separating-transfer station and a vertical transfer position.

12. Installation according to claim 9 whether alone or in combination with claim 10 or claim 11, wherein the buffer station has a vibrating conveyor of spiral-shaped construction.

13. Installation according to any of claims 1 or 5 to 7 wherein the singling-transfer station is constructed as a unit comprising a movement path for prefabricated inserts with a stop limiting the movement of the latter, a magazine pivotable between a horizontal charging position and a vertical transfer position by means of a first cylinder and piston assembly and having extendable frames for as many inserts as can be received simultaneously in the mould, a corresponding number of second cylinder and piston assemblies having ejectorsfortransferring the inserts into the magazine, the ejectors including members for determining the axial position of the inserts, a third cylinder and piston assembly for ensuring that in the vertical transfer position of the magazine the frames are extended by a distance corresponding to that between the mould cavities, equal-length connecting screws of the individual frames ofthe magazine being used as distancing stops for them, and a fixed wedge surface in the region of the transfer position to feed the inserts towards the loading multiple grippertongs of the feeder-discharge device.

14. Installation according to any preceding claim having loading multiple gripper tongs and unloading multiple gripper tongs forming part of a feeder discharge device of which a pivoting mechanism, constructed as a parallelogram linkage, is movable between horizontal and vertical positions, and in its vertical position the head of an associated pivot arm together with any castings gripped by unloading tongs mounted thereon is hingeable laterally through 909 in order to discharge the castings and means are provided in the head of the pivot arm for a grippertongs displacement simultaneously with and in the same direction as ejector pin movement in the movable mould section, the head of the pivot arm additionally having guide tracks extending vertically when the pivot arm is in its pivoted position between the mould sections, each guide track being for a U-shaped carriage with associated displacement drive, each carrying a similargrippertongsfor simultaneous loading of a plurality ofinserts into the mould or for simultaneous discharging of a plurality of composite castings from the mould in the same pivoted-in position of the pivot arm and each carriage also carrying means for the multiple gripper tongs displacement in the same direction as the ejection movement.

15. Installation according to claim 14 wherein each of the two gripper tongs is constituted by two similar clamp jaws carried in a frame fixed to a support profile, the clamp jaws being guided at each of their two ends on a bolt mounted in the frame, the ends being held spaced apart by springs, the facing surfaces of the clamp jaws having a plurality of recesses, the backs of the clamp jaws having stepped wedge surfaces, each of the gripper tongs including a U-shaped actuating fork guided for longitudinal sliding movement externally on the frame, the actuating fork being operatively associated with a drive and connected by connecting straps to a plurality of wedges co-operating with the wedge surfaces of the clamp jaws.

16. Installation according to claim 15 wherein lateral projections are provided on the recesses of the clamp jaws for engagement in bores of the inserts.

17. Installation according to any of claims 1,6 or 7, whether alone or in combination with any claim appendant thereto, wherein the stripper device has a main frame with a guideway arranged thereon oriented parallel to the longitudinal direction of the pressure casting or injection moulding machine, the guideway being for a carriage which is displaceable by a drive between a loading position located in the discharge region of the unloading tongs of the feeder-discharge device and a work position in the interior of the stripper device, the carriage having bores arranged correspondingly to the configuration ofthe mould cavities in the mould to accommodate the composite castings, the carriage also having a resilient support to support the still unseparated sprues, the stripper device having columns anchored to the main frame which carry a number of punching tools corresponding to the number of composite castings to be processed, the punching tools being fixed in suitable holding frames shaped similarly to the contours of the composite castings and raisable and lowerable by means of a drive system arranged above the work position of the carriage and coaxially alignable to its bores by means of centering elements, the stripper device also having a first chute for the composite castings separated from their sprues and in the region of the resilient support a second chute for the punched-off sprues, the two chutes being connected to the guideway intermediate the loading position and the work position of the carriage.

18. Installation according to claim 17 wherein each of the punching tools has a central bore which extends through the associated holder frame and through a plate of the drive system of the punching tool that accommodates the frames, the said central bore being located coaxially with the relevant bore of the carriage and having in the peripheral region of the holderframes and of the plate carrying the same a maintaining device for auxiliary handling elements to be separated from the composite castings, the stripper device further having a power-actuated raising and lowering device arranged at the underside of the main frame for transferring the auxiliary handling elements out of the composite castings into the central bores of the punching tools, the raising and lowering device being provided with a corresponding number of ejectors slidable from beneath into said central bores, a further ejector for each punching tool being provided on a yoke plate supporting the drive system, said further ejectors being slidable from above into the relevant central bore when the punching tools are raised after each punching operation, the stripper device further having a tiltable third chute articulated to the carriage by way of a bracket and guided by rollers on a rocker four removing the auxiliary handling elements, the third chute being movable between an accepting position horizontally below the punching tools which it occupies whilst the carriage is in its loading position and an inclined transfer position which it occupies whilst the carriage is in its work position.

19. Installation according to any preceding claim wherein the pressure casting or injection moulding machine has a multiple mould with a symmetrical sprue system and with devices operable independently of the mould closing device which are associated with each mould cavity for individual compensation of height differences of the prefabricated inserts, each mould cavity on the end face of the movable mould section having a mould endpiece which delimits the mould cavity and which is displaceable at right angles to the mould division plane for height compensation, each mould end piece having a vertically extending venting device movable with it through the same stroke, the venting device including a vent channel which on the one hand can be connected and disconnected with a venting bore by a driven shut-off bolt guided in a parallel guide bore, the venting bore coming from the respectively associated mould cavity, and which on the other hand is in constant communication with atmosphere by way of a catch chamber.

20. Installation according to claim 19 wherein a head part of the shut-off bolt and a head part of the housing of the venting device are of tee-shaped construction and each guided in an undercut of which one is provided on the piston rod of a pressure piston of an actuating cylinder and piston assembly for the shut-off bolt, and the other in a bracket, and the actuating cylinder and the bracket are fast with the movable mould section.

21. Installation according to any preceding claim wherein the mould of the pressure casting or injection moulding machine, the loading and unloading tongs of the feeder-discharge device and any separating-transfer station and the stripping device are constructed for the simultaneous production of four composite castings.

22. Method of producing composite castings incorporating prefabricated inserts which include the steps of transferring a multiplicity of inserts to a loading multiple gripper tongs; moving the loading tongs and an unloading multiple gripper tongs into position between the opened mould sections of a multiple mould of a pressure casting or injection moulding machine; whilst (a) the unloading tongs is in an operative position relative to a first mould section to unload composite castings from it and (b) the loading tongs is in an inoperative position relative to the other mould section offset from its operative position: spraying that other mould section with release agent; moving the unloading tongs to an inoperative position offset from its operative position, and moving the loading tongs from its inoperative position to its operative position relative to that other mould section to load inserts into it; spraying the first mould section whilst the unloading tongs is in its inoperative position and the loading tongs is in its operative position; moving both multiple gripper tongs out of position from between the mould sections; discharging composite castings from the unloading tongs; and stripping the composite castings from their sprue systems.

23. Installation for the production of composite castings incorporating prefabricated inserts, substantially as shown in and hereinbefore described with reference to Figures 1 to 8 or Figures 8 to 11 of the accompanying drawings.

24. Method of producing composite castings incorporating prefabricated inserts, substantially as herein before described with reference to the accompanying drawings.

25. Installation for the production of composite castings (67) by casting round prefabricated inserts (7) in the mould (4, 5) of a pressure casting or injection moulding machine (1) which can also be usedforthe production of conventional castings without inserts, with which ancillary devices are associated for feeding of the inserts (7) and discharge of the composite castings (67), for mould spraying and for separating the composite castings (67) from their sprue systems (90) and from auxiliary handling elements (8), characterised in that between the feeder-discharge device (24 to 30) and a station for prefabrication of the inserts (7) located exteriorly of the installation there is provided an independently automatic separating-transfer station (13,16,172) in conveying connection (10, 12, 145) with the insert prefabrication station and that the feeder-discharge device (24 to 30) has respective multiple gripper tongs (24,26) for loading of the inserts (7) and for unloading of the composite castings (67) which in their common pivoted-in position between the open mould sections (4, 5) can be alternately lowered vertically in synchronism with a mould spraying device (6) each time the latter is to spray one of the mould sections (4, 5).

26. Composite castings incorporating prefabricated inserts, whenever produced by an installation or by a method claimed in any preceding claim.