Source: http://www.google.fr/patents/US5244608?hl=fr
Timestamp: 2013-05-22 10:19:20
Document Index: 46654043

Matched Legal Cases: ['arts 2', 'art 2', 'art 4', 'art 4', 'art 4', 'art 4', 'art 2', 'arts 2', 'art 2', 'arts 2', 'arts 2']

Brevet US5244608 - Method and a system for manufacturing shaped objects of wood dust - Google�BrevetsRecherche Images Maps Play YouTube Actualit�s Gmail Drive Plus » Recherche avanc�e dans les brevets | Historique Web | Connexion Recherche avanc�e dans les brevets BrevetsA moulding process and system for producing small wooden objects such as, for example, pipe heads or furniture handles from a moulding material formed of an aqueous suspension of wood dust. The moulding material is injection moulded into injection mould parts in which electrodes are placed for subjecting...http://www.google.fr/patents/US5244608?utm_source=gb-gplus-shareBrevet US5244608 - Method and a system for manufacturing shaped objects of wood dust Num�ro de publicationUS5244608 AType de publicationOctroi Num�ro de demande07/778,210 Date de publication14 sept. 1993 Date de d�p�t15 juin 1990 Date de priorit�15 juin 1989Autre r�f�rence de publicationEP0477254A1EP0477254B1WO1990015704A1 InventeursUlrik F. Andersen Cessionnaire d'origineMix-Wood Aps Classification aux �tats-Unis264/449425/437425/174.80E264/328.18264/328.2425/812425/DIG.460425/547264/37.29264/478264/DIG.490264/335264/328.16 Classification internationaleA24F1/00D21J3/00B29C45/00B29C43/02B29C43/52B29K103/00B27N5/02B27N5/00A24F1/32B29C45/73B29C35/12 Classification coop�rativeB29C45/73B29C35/12B27N5/02D21J3/00B29K2511/14B29C45/0013A24F1/32 Classification europ�enneD21J 3/00B29C 35/12B29C 45/00EA24F 1/32B27N 5/02B29C 45/73R�f�rencesCitations de brevets (8) R�f�renc� par (9)Liens externesUSPTO Cession USPTO EspacenetMethod and a system for manufacturing shaped objects of wood dustUS 5244608 A R�sum� A moulding process and system for producing small wooden objects such as, for example, pipe heads or furniture handles from a moulding material formed of an aqueous suspension of wood dust. The moulding material is injection moulded into injection mould parts in which electrodes are placed for subjecting moulding cavities to a HF-heating field such that both a rapid curing of a heat setting glue agent in the aqueous wood dust mass and a rapid driving out of a major part of the water is realized. The moulding cavities include exhaust or release channels for steam resulting from the evaporation of the water of the moulding material and an arrangement is provided for maintaining the mould parts together in spite of the high steam pressure developed in the mould cavities.
I claim: 1. A method of manufacturing moulded bodies of a moulding material containing wood dust, a heat activated glue agent and water the method comprising the steps of injection moulding the moulding material into a mould cavity provided in opposed mould parts fashioned of a hard, heat resistant and dielectric material, subjecting the moulded body to an HF heating field between a metallic plate electrode located in the respective tool mould parts spaced behind a bottom portion of the mould cavity so as to promote a curing of the glue agent and promoting an expulsion of the water from the moulded body by evaporation of the water, venting steam resulting from the evaporation through at least one channel connecting the mould cavity with the environment, and, at least initially holding the mould parts together with a pressure sufficient to resist a pressure of steam created by rapid heating of the moulded body.
DETAILED DESCRIPTION Referring now to the drawings wherein like reference numerals are used throughout the various views to designate like parts and, more particularly, to FIG. 1, according to this figure, a pair of mould parts 2, 5 are provided, with the mould parts being adapted to be arranged just as the mould parts in an ordinary conventional injection moulding machine for plastic, that is, with a fixed mould part 2 and a movable mould part 4, and with the movable mould part 4 being carried on or by rearwardly projecting metallic rods 6, connected to a mechanism for pushing forward and retracting the mould part 4 to and from a position in which the mould part 4 is pressed firmly against the mould part 2. Cooperating moulding cavities 8 are provided in interfacing front sides of both mould parts 2, 4 and, at a rear side of the mould part 2, a central inlet opening 6 is provided for receiving an injector head 12 on a supply pipe 14. The supply pipe 14 is provided in a conventional manner with a feed worm conveyor (not shown) for conveying the moulding material from a supply container (not shown) to the opening 10. The supply pipe 14 and the injector head 12 are displaceable in an axial direction such that the supply pipe 14 and the injector head 12 can be moved between a projecting position in engagement with the opening 10 and a retracted position spaced therefrom.
For effecting a moulding operation, the mould parts 2, 4 are pressed firmly together, and the worm pipe 14,12 is moved into engagement with the opening 10, whereafter, the worm conveyor in the supply pipe 14 is actuated to supply a suitable amount of moulding material into the joined mould. The injection pressure may be, for example, but 900 kp/cm.sup.2, while the pipe nozzle 12 may engage the opening 10 with a pressure of some 5 tons. The closing pressure between the mould parts 2, 4 has to be considerably higher, e.g. some 200 tons for a moulding volume of 300-400 cm.sup.3.
Thereafter, the HF generator is actuated for effecting a powerful heating of the moist moulding material in the moulding cavities, such that the water is driven out by a strong evaporation, for example, out through the outwardly open opening 10 and passages 22. The required heating time may depend of the thickness or volume of the moulding. In the example shown, the moulding is a body for the making of eight furniture handles as shown in FIG. 5, and the total volume of this body may, for example be 325 cm.sup.3. A suitable heating time will be 15-20 seconds. While the heating time period is sufficient, it is also possible to make use of a still stronger HF field for driving out the water still more rapidly, but the stability of the moulding system would be jeopardized, as a very high inner steam pressure is created. Preferably, the heating should not be driven beyond some 95 between 75 should be adjusted accordingly. By its injection into the mould, the moulding material should not give rise to any considerable development of frictional heat, since hereby a hardening of the glue agent may be initiated already prior to the mould being filled. This could speak for a rather high percentage of water, e.g. 20%, but as already mentioned, an alternative is the use of a very small amount of a gliding agent, for example, an amount of 0.1-2.0% of the dry glue material.
After the HF heating the mould parts are separated, whereby the entire, hardened moulding body will remain seated in one of the mould parts. The moulding, as indicated in FIG. 4, is ejected from the mould body by compressed air that is introduced through the channels 26 and the valves 28, these being check valves in order to counteract an intrusion of moulding material into the channels. Upon ejection of the moulding body from the mould part, the moulding body is cut along the dotted lines S in FIG. 4, whereby a total of 4 are formed. The handle these members 40 may be provided with a drilled hole 42, (FIG. 5) in their respective end faces. By cutting, the handle members 40 will appear with overall unbroken moulding surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for the purposes of illustration only, one embodiment in accordance with the present invention, and wherein:
FIELD OF THE INVENTION The present invention relates to a method of manufacturing moulded bodies based on wood dust, for example, smoking pipe heads.
BACKGROUND OF THE INVENTION FR-547,636 proposes manufacturing pipe heads by a moulding process by which preferred pipe wood, for example bruyere, can be used in dust form in the moulding mixture holding various binding and curing agents.
SUMMARY OF THE INVENTION The aim underlying the present invention essentially resides in providing a method by which it is possible to produce moulded bodies such as pipe heads having a very high content of wood dust and being economically producible with a brief processing time of, for example, thirty seconds, as compared with, for example, FR-547,636 requiring a curing time of some sixty hours.
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