Expansible chamber devices – Cylinder detail
Reexamination Certificate
1998-07-14
2001-03-06
Lopez, F. Daniel (Department: 3745)
Expansible chamber devices
Cylinder detail
Reexamination Certificate
active
06196112
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a screwable pressure actuated operating cylinder with closure elements for closing the cylinder tube, which can be employed to produce translational movement of mechanisms in the field of fluidic energy transmission utilizing flowing media (liquids, gases) as pressure media, where this operating cylinder is particular suitable for high pressure aggressive media.
2. Prior Art
Screwable pressure medium actuated operating cylinders in accordance with German patent DE OS 19 215 43 are known, in particular hydraulic differential or plunger pistons, whose cylinder tube, capable of accepting one piston, is provided with closure elements provided at the lower or head end. These closure elements are screwed up over the outer thread of the cylinder tube, and closed securely against leaks via a ring seal located on the inner thread.
Furthermore, screwable operating cylinders are known in accordance with patent EP 060 17 36 A 1, where the thread carrying the closure elements is arranged in the inner shell of the cylinder tube and where sealing is achieved via sealing elements. At the same time, screwable operating cylinders having cylinder tube inner-, or cylinder tube-outer threads are known, in which sealing is achieved by means of an elastomer seal, which is located in the ring face of the cylinder tube or, also, as described in German patent DE 35 17 137 A 1, as a face seal of the guide closure element.
All known screwable operating cylinders always achieve cylinder tube sealing by the insertion of elastomer sealing elements.
In these embodiments the frequency of faults developing in the high pressure range as well as the complicated and therefore expensive metal-cutting required in manufacture.
Pressure medium-actuated linear motors in threaded embodiments necessitate highly developed manufacturing technology and are therefore expensive to manufacture. Nevertheless, they can only be used to a limited extent, especially in the aggressive high pressure range. If the components of the operating cylinder are coated, in order to make them resistant against aggressive media, additional costs arise for the manufacture of the joining elements, which also remain prone to frequent faults due to the effect of high pressure substances.
Known technical solutions require highly skilled personnel for manufacture of the individual components of the operating cylinder, so that the manufacturing costs for known technical solutions are high.
SUMMARY OF THE INVENTION
The proposed solution is distinguished from the above-described prior art operating cylinder, in that it does not exhibit the aforesaid disadvantages.
It is the object of the invention to develop a screwable pressure-medium actuated operating cylinder, which operates with reliable sealing performance in the high pressure range, even with aggressive media, which can be produced economically and which, using mainly non-machining manufacturing technology, is simple to manufacture, and has advantages resulting therefrom.
These objects are attained according to the invention by a fluid pressure actuator comprising a cylinder tube capable of accepting at least one piston and a closure element provided on a first end of the cylinder tube. Respective sealing chamfers are provided on the closure element and on the first end of the cylinder tube, which each have a slope between 6 degrees and 12 degrees. Respective screw threads are provided on the closure element and the first end of the cylinder tube, near the corresponding sealing chamfers. Portions of the closure element and the first end of the cylinder tube including the sealing chamfers are made of a material having a modulus of elasticity in a range between 60*10
3
N/mm
2
and 250*10
3
N/mm
2
plus or minus 10%, and an elastic limit in a range between 200 and 1050 N/mm
2
, over a temperature range of 0° C. and 200° C., so that, when the closure element is fixed to the first end of the cylinder tube by respective screw threads on the closure element and the first end of the cylinder tube, the sealing chamfers of the closure element and the first end of the cylinder tube are pressed on each other and thus interact to prevent leakage of fluid between the closure element and the first end of the cylinder tube.
Advantageous additional features are claimed in the appended dependent claims.
In particularly preferred embodiments the sealing chamfers and the screws threads are preferably both formed by a non-cutting operation and the sealing chamfers have a surface roughness that does not exceed 0.4 microns.
The advantages of the invention include the following: the operating cylinder functions in a trouble-free manner in the high pressure region, its manufacture is simpler and expensive machining is not required.
Furthermore, the operating cylinder is capable of operation in aggressive media, where the need of coating the operating cylinder does not arise, due to the resistance achievable, in the case of suitable material selection. As a result of forming the operating cylinder as a screw-press connecting component, expensive welding connections are avoided, and replacement of worn individual components can be carried out without difficulties. Higher surface pressure on the sealing surfaces is achieved as a result of the non-machining manufacture of the sealing surfaces. Manufacture and assembly of the components is simple, and can be carried out by inexperienced personnel, who are not specifically trained.
REFERENCES:
patent: 2345871 (1944-04-01), Hallberg
patent: 2981575 (1961-04-01), Leman
patent: 3867824 (1975-02-01), Takagi et al.
patent: 5372529 (1994-12-01), Binversie et al.
patent: 5415079 (1995-05-01), Ching
patent: OS 19 215 43 (1965-05-01), None
patent: 35 17 137 A1 (1986-11-01), None
patent: 0 601 736 A1 (1994-06-01), None
patent: 35861 (1981-04-01), None
Beer et al, Mechanics of Materials, McGraw-Hill, 1981, front cover, p. 585.
Buemach Engineering International B.V.
Lopez F. Daniel
Striker Michael J.
LandOfFree
Screw-on pressure medium-actuated working cylinder with... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Screw-on pressure medium-actuated working cylinder with..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Screw-on pressure medium-actuated working cylinder with... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2451319