Hydraulic system on an injection molding machine
CA 2043151 A1 · Owner: Hehl, Karl · Inventors: Hehl, Karl
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The hydraulic system comprises a 4/4-way valve, which is adapted to control the velocity of the mold-closing operation and the fluid pressure during said mold-closing movement and to assume three consecutive control positions, in each of which fluid pressure is applied to a stationary piston of an advance-retract cylinder from a first cylinder chamber, which is nearer to the mold. One of said control positions is a differential control position, in which pressure fluid displaced from the second cylinder chamber of said advance-retract cylinder, which second chamber is remote from the mold, is supplied to a pressure conduit through a branch passage, which includes a non-return valve. The …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed May 23, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 23, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 23, 2013.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.