Plastic and nonmetallic article shaping or treating: processes – With measuring – testing – or inspecting – Positioning of a mold part to form a cavity or controlling...
Patent
1997-06-25
1999-12-07
Heitbrink, Jill L.
Plastic and nonmetallic article shaping or treating: processes
With measuring, testing, or inspecting
Positioning of a mold part to form a cavity or controlling...
73766, 2643281, 425145, 425149, 425170, B29C 4576
Patent
active
059977809
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method of adjusting a zero point of a pressure detector of an injection molding machine and an apparatus for carrying out the method.
DESCRIPTION OF THE RELATED ART
An injection molding machine, in which a pressure applied to a movable member is detected by a pressure detector provided corresponding to the movable member, is known. For example, a machine, in which an injection holding pressure or a back pressure in metering is sampled by a pressure detector installed on the base of screw, is well known. The most commonly used pressure detector is a load cell, that is a pressure detector comprising an elastic member and a strain gauge positioned on a power transmitting path between a movable member and a drive source of the movable member.
Since the strain gauge is designed to measure a deformation of metallic wire caused by pressure by changing the deformation into an electric resistance, a pressure applied to the movable member can be detected by directly affixing the strain gauge to the functionally necessary elastic member positioned on a power transmitting path between the movable member and the drive source or the movable member itself and the like. However, when the rigidity of such an elastic member is extremely high and therefore the deformation due to pressure is not sufficiently large, it is sometimes difficult to detect the pressure with high accuracy. Because of this problem, a member which is more elastically deformable, called a strain-sensitive member, is usually disposed on the power transmitting path, and a strain gauge is affixed to this member in order to constitute a pressure detector.
In general, the strain-sensitive member or the load cell body means the aforesaid member which is easily elastically deformable. Needless to say, the strain gauge itself is also a kind of strain-sensitive member.
As an example of the pressure detector using the load cell, a general construction of the pressure detector which is adapted to detect pressure applied to a screw shaft will be described briefly with reference to FIG. 1, which shows a cross section of a principal portion of an injection mechanism.
In FIG. 1, reference numeral 1 denotes a front plate of an injection unit. Fixed to the front plate 1 are two or four tie rods 2 provided between the front plate 1 and a rear plate (not shown) positioned on the right side in the figure. A screw pusher plate 3 is slidably installed to the tie rod 2 through bushings etc.
A screw sleeve 4, which is rotatably installed to the screw pusher plate 3 through two angular bearings, is rotated by a metering motor (not shown), which is fixed to the screw pusher plate 3 side, through a toothed pulley 5 fixed to the sleeve 4 and a timing belt (not shown) etc. set around the pulley 5.
An injection cylinder 6 fixed to the front surface of the front plate 1 incorporates a screw 7 for metering and injection, and the base of the screw 7 is fixed to the screw sleeve 4. The screw is rotated for metering and kneading in response to the rotation of the screw sleeve 4.
Further, a ball screw 8, which is used as a screw for motion, is attached to the rear plate, not shown, stationarily in the axial direction but rotatably around the axis. The ball screw 8 can be rotated by an injection motor fixed on the rear plate side through a timing belt and the like. The front end portion of the ball screw 8 protruding from the rear plate toward the front plate 1 is screwed into a ball nut 9 (also called a socket) stationarily installed on the back surface of the screw pusher plate 3. As the ball screw 8 rotates, the screw pusher plate 3 and all the members attached to the plate 3 as a whole move back and forth with respect to the front plate 1, and the screw 7 fixed to the screw sleeve 4 moves back and forth in the injection cylinder 6.
A load cell 10, which constitutes a pressure detector for detecting an injection holding pressure or a back pressure acting on the screw 7, is disposed at the base of the screw 7, more particular
REFERENCES:
patent: 4547859 (1985-10-01), Wiggins
patent: 5206034 (1993-04-01), Yamazaki
patent: 5213726 (1993-05-01), Ramsey et al.
patent: 5553481 (1996-09-01), Arai
patent: 5567367 (1996-10-01), Ito et al.
Ichihara Toshiaki
Ito Susumu
Kamiguchi Masao
Neko Noriaki
Yamanaka Katsuyuki
Fanuc Ltd
Heitbrink Jill L.
LandOfFree
Zero point adjusting method for pressure detector of an injectio does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Zero point adjusting method for pressure detector of an injectio, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Zero point adjusting method for pressure detector of an injectio will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-820196