US 6,254,371 B1Granted

Press system for urethane parts

AssigneeKonal Engineering and Equipment Inc.

InventorsDouglas J. McNally, Keith Wallace

Life of this patent

Estimating the term…

Loading patent…

Abstract

The mold press includes a drive arrangement for controlling press movement and closure force. The drive arrangement includes a pair of generally identical drive units connected between upper and lower press plates adjacent opposite longitudinal ends of the press. The drive units in a preferred embodiment each employ a ball-screw drive arrangement. The screw shaft extends vertically between the top and bottom press plates. The screw shaft engages a ball nut mounted on one press plate, typically the bottom press plate which is disposed for movement toward and away from the top press plate. A first high speed drive arrangement employing a first electric motor is coupled to the screw shafts for effecting high speed opening and closing of the bottom press plate. A second low-speed driving arrangement including a second electric motor is drivingly connected to the ball-nut assemblies for permitting low-speed but high-torque driving of the nut units for final closing of the press and application of the desired press force. Each drive unit has the screw shaft resiliently supported for limited axial displacement relative to the upper press plate so that, when the second drive system is activated to effect final closure of the mold, one or the other of the screw shafts can be axially displaced a small amount if necessary so as to permit full closure between the opposed upper and lower mold parts even though irregularities may cause one longitudinal end of the mold parts to contact and close prior to the other longitudinal end.

A rim press for permitting molding of an element between first and second mold parts which when closed cooperate to define a mold cavity therebetween, said press comprising:

a frame;
first and second platen arrangements supported on said frame and respectively defining thereon a first press surface on which said first mold part is mounted and a second press surface disposed in opposed relation with said first press surface and on which said second mold part is mounted;
a drive arrangement drivingly interconnected to said first platen arrangement for controlling movement thereof between open and closed positions of said mold parts, said drive arrangement including a pair of drive shaft units drivingly connected to said first platen arrangement and disposed at opposite ends thereof, each said drive shaft unit including an elongate screw shaft extending between and rotatably supported relative to said first and second platen arrangements and which is rotatably engaged with a nut member which surrounds said screw shaft and is mounted on said first platen arrangement for movement therewith in response to relative rotation between said nut member and said screw shaft;
and
a brake arrangement associated with one end of each said screw shaft, each said brake arrangement including a first friction brake, a second friction brake cooperating between said frame and said screw shaft, and a resilient biasing structure disposed between said first and second friction brakes and exerting a spring force on said screw shaft to urge same axially in a direction of closing movement of said first platen arrangement, said first friction brake automatically engaging and holding said screw shaft nonrotatable in response to an axial load imposed on said screw shaft during final closure of the mold parts causing said screw shaft to displace axially in a direction opposite to said closing direction and in opposition to said spring force, and said second friction brake automatically engaging and holding said screw shaft nonrotatable in response to axial displacement of said screw shaft in said closing direction as effected by said resilient biasing structure during initial cracking of the mold parts.

2 more elements

Facts

Application

09/041,068Filed 12 Mar 1998 · continuation in part

Priority

21 Aug 1997

Granted

3 Jul 2001

Term ends

Not estimatedThe source records don’t support an estimate.

Classification7 codes

B29C 33/36
Movable, e.g. to or from the moulding station: continuously movable in one direction, e.g. in a closed circuit
B29C 33/22
Opening, closing or clamping: by rectilinear movement
B29C 45/0441
Using movable moulds or mould halves: involving a rotational movement
B29C 2045/0483
Using movable moulds or mould halves: pivotally mounted mould halves

Abstract

Claims11