| 1. | A method of lubricating the form tools of a die cas¬ ting machine, a mixture of a lubricant with or without a particularly intended cooling capacity as well as a propellant gas, e.g. compressed, being sprayed on the form tools subsequent to opening them up, and said mix¬ ture being fed through nozzles (40,41), mounted on ro¬ tary means (27), c h a r a c t e r i z e d in that said mixture is fed in a way which is intermittent as regards the working angle and the rotational movement of said rotary means (27) , namely solely within each lubrication area, and in that between said lubrication areas no lubricant feeding or only a reduced such fee¬ ding takes place. |
| 2. | A method according to claim 1, c h a r a c t e ¬ r i z e d in that said nozzles (40,41) are used to serve one form tool half each. |
| 3. | A device designed to carry out the method according to claim 1, which device (1) is designed to be inserted between the form tools of a die casting machine subse¬ quent to the opening up of the mold, a mixture of a lub¬ ricant with or without a particularly intended cooling capacity and a propellant gas, e.g. compressed air, be¬ ing sprayed on said form tools via nozzles (40,41) mounted on rotary means (27), c h a r a c t e r i z e d in that said device comprises predetermined feeding places (9) for said mixture, separated from each other in the rotational direction of said means (27) , which feeding places are successively connected due to the rotation of said means, which is designed as a chain wheel or the like and driven by means of a motor (31) , the hub (19) of said chain wheel or the like being provided with bores (35,36), which when said wheel ro tates successively are connected to said feeding places. |
| 4. | A device according to claim 3, c h a r a c t e ¬ r i z e d in that said device (1) comprises a yoke (2) , which is supported by cylinders, preferably hydraulicly driven and designed to displace said yoke, when a lubri¬ cation is done, and means mounted on said yoke to a po¬ sition between said form tools, and in that from the ends of said yoke two mutually parallel arms (3,4) pro¬ ject, the ends of which, which are turned away from said yoke, support between themselves a shaft (5) , which is fastened by means of cramps or the like (6) in such a way, that it is completely stationary in re¬ lation to said yoke. |
| 5. | A device according to claim 4, c h a r a c t e ¬ r i z e d in that said shaft (5) is provided with pre¬ ferably central axial ducts (7,8) , which in the central area of said shaft as regards its longitudinal direc¬ tion end in one each of said feeding places (9) , con¬ stituting branch systems, comprising a plurality ofra¬ dially outwardly directed ducts, which end freely in the periphery of said shaft. |
| 6. | A device according to claim 5, c h a r a c t e ¬ r i z e d in that said ducts (7,8) at the ends of said shaft are connected to one feeding duct (10) each for said mixture, in that each such duct leads to a sto¬ rage tank (11) for lubricant, and in that in said duct preferably is connected, e.g. adjacent said storage tank, an adjustable dosage pump (12) , on either side of said pump connection suitably nonreturn valves (13, 14) being connected in the duct, which two valves are opened up in the direction from the storage tank. |
| 7. | A device according to claim 6, c h a r a c t e ¬ r i z e in that in the flow direction downstreams of said nonreturn valves (13,14) is in the duct (10) one additional nonreturn valve (15) connected, having the same direction, downstreams of which a connection (16) from a propellant gas source (17) , e.g. a compressed air compressor, ends in the duct (10) , and in that bet¬ ween said source and said duct preferably a nonreturn valve (18) , which opens up towards said duct, is con¬ nected. |
| 8. | A device according to any of claims 47, c h a ¬ r a c t e r i z e d in that said shaft (5) is enclosed by said hub (19) , which preferably is only half as long as the shaft and is rotationally mounted roughly in the central area of the shaft, ball bearings (21) being mounted in the ends of the hub, inside which ball bea¬ rings radial seals (23) are mounted in recesses (22) having e.g. smaller diameters, and/or in that around the central area of said hub a flange (24) , preferably on all sides, is disposed having a few axial through holes (25) for receiving threaded bolts (26) , by means of which and nuts (28) said rotary means (27) is non relatively revolvingly fastened to said hub, and/or in that around the gear ring (29) of said rotary means (27) , designed as a chain wheel, a roller chain or the like (30) is applied, which is driven by said motor (31) , suitably a so called plate motor, via a chain wheel (32) driven by the motor, which is fastened on one of said arms (4) . |
| 9. | A device according to any of claims 38, c h a ¬ r a c t e r i z e d in that said hub (19) is provided with bores (35,36), which extend from its central part and extend in preferably diametrically opposite direc¬ tions somewhat obliquely outwards with an angle of pre¬ ferably about 10 , and which are connected to ducts (38,39) leading to one nozzle each (40 and 41 respec¬ tively) on one side each of said rotary means (27) in two preferably diametrically opposite directions, and/ or in that said nozzles (40,41) are provided with a threaded pin (42) , by means of which they are inserted through a hole (43) in said rotary means (27) and fas¬ tened on its opposite face by means of a nut (44) , said nozzles having a radial inlet hole (45) for the corre¬ sponding duct (38 and 39 respectively) as well as on their outlet side a preferably threaded cavity (46) , designed to receive elements, already known per se, de¬ signed to' influence/shape/direct the mixture, which is discharged from said nozzles. |
| 10. | A device according to any of claims 39, c h a ¬ r a c t e r i z e d in that in addition to said rota¬ ry nozzles (40,41) stationary nozzles (47,48) are used, which are fastened to the support elements (3,4) of the device and designed to be fed with said mixture from either the same source (11) and the same duct (10) as said rotary nozzles or via their own system. |
The present invention relates to a method of lubrica¬ ting the mold tools of a die casting machine as well as a device designed to carry out this method.
Die casting machines must be lubricated during every casting cycle. This need has until now been met bymeans of lubricating devices, which are stationary when used, a large amount of spray nozzles being used, each one of which being selected to serve a certain area of themold tools. Without an adequate lubrication an oxide forma¬ tion and coatings as well as an increased service need may occur. The service life of the tools may decrease considerably in this way. It is very difficult to pre¬ cisely adjust the adequate amount of lubricant andpro¬ pellant, e.g. compressed air, since the nozzles easily can be clogged with impurities. It is also difficult to accurately distribute the lubricant mixture to all the nozzles, and possible cloggings of one or several nozz¬ les may influence the rest of them. On the other hand it is also important to avoid feeding too much lubri¬ cant, since this may result in undesirable coatings. An additional drawback of the already known lubrication devices is that so called last runnings occur to a large extent. These last runnings end up on the shop floor and on machine parts, where they constitute an impurity and may increase the fire hazard. In spite of these draw¬ backs the already known devices are comparatively ex¬ pensive due to a complicated construction, a conside¬ rable material and component requirement as well as time-consuming assembly work. It is often difficult or impossible to adjust the lubrication to the varying mold tools, which are often used in die casting ma¬ chines, at least in an optimal manner.
DE-B-25 49 059 relates to a spraying device designed for die casting forms, which device comprises a rotary disc having a plurality of radially projecting tubes,
along which spray holes are disposed, from which a li¬ quid-air-mixture continuously is fed during the entire spraying process. Thus, this device is impaired by the drawbacks described above.
WO-79/00139 shows and describes a spray nozzle designed for die casting forms. The nozzle is provided with spe¬ cial ducts for the feeding of compressed air and a rota¬ ry wheel having oblique vanes, which wheel is designed to produce different ato ization patterns thanks to va¬ rying speeds. This nozzle is built in a rather special and complicated way but no conclusions whatsoever can be drawn from this document as to the nature and the function of those devices and the like, in which this nozzle is to be used.
SU-1 315 119 shows and describes a spray distribution head having its own displacement mechanism. The head is designed, by means of said mechanism, to be fed with either air or a lubricant and also to be dis¬ placed to a vertical or a horizontal rotation posi¬ tion. This document does not mention any particular method of lubrication of e.g. various lubrication are¬ as and also does not mention, how or even if the spray distribution head is to be displaced in addition to the lowering of the head into the form. Even this do¬ cument relates to a device having one or several of the. drawbacks of known devices mentioned in the intro¬ duction.
US-A-4 214 704 relates to i.a. a lubrication device designed for die casting machines having a liquid emit¬ ting head, which is mounted on a reciprocating dis¬ placement mechanism, which comprises roller chains and chain wheels designed to insert the device into a po¬ sition between the molds and to retract the same. No rotary lubrication nozzles or the like are used and
even in this case the drawbacks described above have not been solved.
The object of the present invention primarily is to, in the respects mentioned above, improve and develop the conventional lubrication technique and develop the state of the art in this field in various respects.
This object is attained in accordance with the present invention by using a method of the type described in the introduction mainly in such a way as is set forth in the characterizing clause of patent claim 1. Said object is also attained by means of a device mainly according to the first device claim.
Additional characterizing features and advantages of the present invention will be set forth in the follow¬ ing description, reference being made to the accompa¬ nying drawings, in which a preferred but not limiting embodiment is shown. The drawings show in detail: Fig. 1 a lubrication device according to the inven¬ tion, mainly in a diametrical sectional view; Fig. 2 a shaft forming a part of the device shown in Fig. 1 partially in an axial section;
Fig. 3 a diametrical view along line III-III in Fig. 2; Fig. 4 a hub forming a part of the device shown in Fig. 1 in a diametrical axial section;
Fig. 5 a view from the left or the right in Fig. 4; and Fig. 6 a nozzle forming a part of the device shown in Fig. 1 in a diametrical section.
The lubrication device according to the invention is in its entirety designated 1 in the drawings. This device comprises e.g. a yoke 2, which is supported by cylinders (not shown) , which e.g. are hydraulicly driven and de¬ signed to, when the lubrication is done, move the yoke, as well as means mounted on said yoke and described in
the following text, to a position between the molding tools. From the ends of yoke 2 two mutually parallel arms 3,4 project, the ends of said arms, which are turned away from the yoke, supporting in a position between said ends a shaft 5, which is fastened by means of e.g. cramps or the like 6, making the shaft stationarily attached in relation to said yoke. The shaft is provided with prefe¬ rably central axial ducts 7,8, which in the central area of the shaft with respect to its length leads to branch systems 9, one for each duct and comprising a suitable number of radially outwardly directed passages, which freely end in the periphery of the shaft. The two branch systems can be disposed close to each other but theymust not communicate with each other. Ducts 7,8 are" at the re¬ spective ends of the shaft connected to a respective fee¬ der duct 10 for a mixture of a lubricant and a propel¬ lant gas. Each duct 10 is connected to a storage tank 11 containing the lubricant, which suitably is a mold lub¬ ricant known per se. In the duct an adjustable dosage pump 12 is mounted adjacent said storage tank. On each side of the pump connection suitably nonreturn valves 13,14 are mounted in the duct, which two valves open up in the direction from the storage tank. The purpose of the nonreturn valves is to, when the lubricant fee¬ ding is done, cut off a continued feeding from the sto¬ rage tank as regards valve 13 and open up respectively for a. dosed amount of lubricant, the dosing being done by means of pump 12, which opens up alve 14 with its pressure. In the flow direction suitably an additional nonreturn valve 15, having the same direction, is moun¬ ted in duct 10, downstreams of valve 14, and downstreams of valve 15 a connection 16 from a propellant gas source 17, e.g. a compressed-air compressor, is led into duct 10. A nonreturn valve 18 suitably is mounted between said source and said duct and opens up towards the duct.
Shaft 5 is enclosed by a hub 19, the length of which
e.g. is only half of length of the shaft and which is rotatable roughly in the central area of the shaft. The rotatability is enhanced by means of ball bearings 21, which are disposed in the ends of the hub in reces¬ ses 20 and inside which radial seal rings 23, e.g. ha¬ ving a smaller diameter, are disposed in recesses 22. Around the central area of the hub, suitably somewhat displaced to one of its ends, a flange 24, preferably all around, is disposed having a few axial throughbores 25 designed to receive threaded bolts 26, by means of which and nuts 28 a chain wheel 27 is non-rotatably fas¬ tened to the hub, i.e. rotatably jointly with the hub. Around gear ring 29 of the chain wheel a roller chain or the like 30 is applied, which is driven by a motor
31, suitably a so called plate motor, via a chain wheel
32, driven by the motor. The motor suitably is fastened to arm 4 by means of fastening means 33 and e.g. socket head cap screws 34. Other driving means of arbitrary type can also be used, e.g. driving means which do not rotate the hub endlessly but only with a certain angle in the form of a reciprocating movement.
Also, the hub is provided with bores 35,36, starting out from the central portion of the hub and extending in di¬ ametrically opposite directions somewhat obliquely out¬ wards with an angle of e.g. about 10 . The ends of these bores then will end up exactly outside the chain wheel, bore 36 suitably extending through a recess 37 in flange 24 in order to end up in said position. The bores are connected to ducts 38,39, which lead to nozzles 40 and 41 respectively on each side of the chain wheel in two diametrically opposite directions. The nozzles are also turned in opposite directions in the axial direction and designed to accomodate their associated mold tool halves. It is shown in Fig. 6, that the nozzles are provided with a threaded pin 42, by means of which they areput through a hole 43 in the chain wheel and fastened to
the other side of the wheel by means of a nut 44. In a radial direction the nozzles are provided with an in¬ let hole 45 for said ducts 38,39 and in the axial di¬ rection on the other side of the pin a cavity 46, e.g. threaded, in which means can be placed, known per se and not shown, designed to influence/shape/direct the mixture, which is fed from said nozzles.
Also, on arms 3,4 stationary nozzles 47,48 can be fas¬ tened, possibly connected to storage tank 11 via duct 10 or their own duct having enclosed and mounted portions by analogy with those described above, why this is not shown in detail.
The device described above and shown in the drawings functions in the following way:
When the mold tool halves of the die casting machine are opened up, the device according to the invention will be inserted between the halves by means of said cylinders, e.g. hydraulicly driven, and motor 31 star¬ ted to rotate chain wheel 27. E.g. about 2 seconds la¬ ter propellant gas source 17 is activated or connected and simultaneously dosage pump 12 is started. The lat¬ ter feeds for e.g. about 5-10 seconds, e.g. 7.5 seconds, a predetermined and adjusted amount of oil, emulsionor the like into duct 10, in which the fed liquid is fine¬ ly divided by means of the pump gas, and the mixture obtained in this way is fed into the shaft and branch systems 9, in which all the branches are filled with the mixture. The hub then rotates and is successively connected with its bores 35,36 to the various branches, from which the mixture then will issue and continue through ducts 38,39 to nozzles 40 and 41, from which the mixture is sprayed exactly when each selected lu¬ brication area has been reached. Between these lubri¬ cation areas no or at least no substantial (reduced) feeding is done, and consequently the device functions
very economically with an extremely small wastage or none at all. In case another feeding pattern is suitable, it is possible to easily and quickly select another shaft having a suitable branch system or use several such branch systems in the shaft, which then through an axial displacement can, with the suitable branch sys¬ tem, match the bores of the hub. Subsequent to the terminated dosage pump feeding the propellant gas source will continue to feed propellant gas through the duct systems for 5-10 seconds in order to thoroughly clean off the transport paths for the mixture and avoid all last runnings. After e.g. 2 more seconds motor 31 is stopped and the device is removed from the mold tools, after which a new lubrication cycle subsequent" to a new molding cycle can be initiated. Nozzles 47,48 can actually be fed with said mixture for an optimal period of time of their own. Also, several chain wheels 27 can be mounted in the same plane and/or in differentplanes, driven by means of the same chain or the like or diffe¬ rent chains in order to obtain different lubrication patterns. The invention can be arbitrarily modified and supplemented within the scope of the inventive idea and the following patent claims.
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