This news article was originally written in Spanish. It has been automatically translated for your convenience. Reasonable efforts have been made to provide an accurate translation, however, no automated translation is perfect nor is it intended to replace a human translator. The original article in Spanish can be viewed at
Anillos para montajes en circuitos oleohidráulicos y neumáticosPmsmart Rastelli presents the AR3 closure ring
Rings for assemblies in circuit oleohidráulicos and tires
Technical Department of Rastelli Pmsmart01/02/2004
The new ring of closing AR3 Rastelli Pmsmart, in addition to the known characteristics and proven functional properties of conventional closing rings of single or double leaf, stands out by its opposite double subject, its absolute tightness, automatic closing, ease of Assembly and be interchangeable with all fittings cutting ring 24 ° DIN 2353.
The ring's AR3 closure of new creation has been studied and developed by Rastelli Pmsmart to offer users a sophisticated product. This ring, in addition to the known features and the proven functional properties of conventional closing rings of simple leaf (TN88) or double (TD88), stands out for the following characteristics:
- Double, opposite subject
- Absolute tightness
- Automatic closing
- Ease of Assembly, with the possibility of replacing the Board of elastomer
- Reduction of the force applied to the Assembly
- It is interchangeable with all fittings cutting ring 24 ° DIN 2353 (ISO 8434-1).
Guarantee of experimentation, testing and trials
AR3 closure ring (Figure 1) has been studied, designed and tested in accordance with the procedures used for the control and verification during the development of new products, according to A Flow Chart defined by the ISO 9001 certification, Rastelli Pmsmart has put in place by organizing the structure of your company.
Figure 1
Product identification scheme
The AR3 rings are fitted with a sign of identification whose key is represented in Figure 1A.
Figure A1
Double, opposite subject
With the new system of opposite double sheet gets more security to the maximum pressures, under loads extreme, shocks and blows of RAM, as well as less likely to break loose and high resistance to vibrations.
The distance between the two leaves and the Special geometry of the rear Blade (Figure 2) creates, in the phase of torque, a second section of resistant material on the tube which, in addition to the first section of resistant material, created by the previous sheetIt determines an increase of more than 40 percent of the new AR3 ring compared to the normal ring of the double blade TD88.
Figure 2
Absolute tightness
Thanks to the particular shape of the ring AR3 at its axial tip corresponding to the previous sheet is has been able to insert a Board of elastomer (Figure 3) that becomes the tapered seating of twenty-fourth body fitting and is linked to the ring through a washer which has been vulcanizada.
Figure 3
In the first phase of closure, ring AR3, pushed by the nut on the twenty-fourth cone of the fitting, leads to the separation of the Board of elastomer washer placing themselves as indicated by Figure 4.
The position of this Board that, under the pressure P of the fluid is essential and precomprimida by force (f) due to the tightening ring AR3 on the tube, ensures a perfect watertight or airtight closure (Figure 4).
Figure 4
Automatic closing limit
The automatic closing of the ring on the body of the fitting AR3 occurs when by effect of the bolts of the nut, AR3 ring slips by the twenty-fourth of the body cone fitting (Figure 5) to (c) and (d) two surfaces are in contact forming a set with the other two surfaces A and Bpreviously United in the first phase of Assembly, so that the operator must stop pushing.
Figure 5
By this system guarantees the most effective grip's AR3 ring in the tube. Only are advised to verify, after loosen the nut, which the two surfaces (c) and (d) are perfectly in touch throughout the entire circumference.
In the final stage of tightening (Figure 6), the washer, separated from the Board of elastomer, has the function to compensate for UN-concentrating possible due to the addition of the tolerances of individual components (body, tube, ring, twist), compressed until forming a whole with the body fitting and AR3 ring.
Figure 6
Ease of Assembly
With the new ring closure AR3 can eliminate those operations and maneuvers which require the editor to check the articulation of the ring into the tube by means of laborious checks such as:
- Mark the tube and the nut to verify the number of laps of it and still have the certainty of a proper closure.
- Use dinamométricas keys for the verification of the force (Nm) necessary for the closure.
To simplify the handling of the various components during Assembly, AR3 closure ring and the Board of elastomer vulcanizada on the washer are provided already trailers.
Instructions for Assembly
Recommendations included in the instructions for the installation of a ring normal Rastelli TN88-TD88 about the lubrication of the pieces, the cleaning of the bodies, the orthogonality of the heads of the tube are valid for the erection of the new ring AR3 (figures 7 and 8), the support of the tube on the level of top of the fitting, etc.
Figure 7
Successive operations of mounting and dismounting can be numerous, because if necessary it can be replaced (Figure 8) only the Board of elastomer, AR3 ring is fixed to the pipe and the washer, coupled to the ring.
Figure 8
Reduction of the force applied to the Assembly
Compared with the normal closure rings TD88 (double leaf), the AR3 need less work to arrive at the end of the closure, since the force used in the montage is significantly lower. Figure 9A presents during the time of torque depending on the laps of closure of the nut using a TD88 ring.
As you can see in this graph (line A), the moment of torsion is growing since the beginning of the closure and it is impossible for the editor clearly perceive the end of the Assembly of the same.
Figure 9A
On the contrary, the graph of the ring AR3 (figure 9B-line B), the course of the moment of torsion with arrangement of the closure of the nut laps increases more weakly on the figure 9A, until you reach one costs steep that he drew in unmistakable way the editor that work is finished (auto locking) preventing the return of more that may damage the closure.
The difference between A1 and B1 areas represents the saved work to the Assembly using the ring's AR3 closure rather than the traditional closing rings.
Figure 9B
Interchangeability
The new AR3 rings are interchangeable with the other rings of closure of single or double leaf which is used with the fittings of cone 24 ° DIN 2353 (ISO 8434-I).
Same manual pre-Assembly utensils can be used with the ring AR3 (blocks temperate type TN I 95) commonly used with normal TN88-TD88 closure rings.
Due to the absolute tightness of the AR3 ring feature, its employment is ideally suited to all the connections with Board NBR (flexible Board): absence of escape and transpiration and dry tube on the outside.
He is encouraged in particular the use of fittings of series TN 400 (TN 419-420-421-426-432) which replace to the TN 119-120-121-126-132, that they are not precerrados, but that they can be used by pressing the ring AR3 on the túbico of the fitting coupling directly during the Assembly.
Figure 9
Technical data
- Surface finish: treatment of shining chrome (white electroplating).
- Materials and maximum working temperatures acceptable "TB" (DIN 2401). Metal parts: steel, rubber parts: NBR.
- Pressure: nominal pressure PN corresponds to a coefficient of safety of PN x 4. Indicated pressure are understood as maxims of work, including the maximum values in normal working conditions and with maximum working temperatures acceptable TB (DIN 2401). For rings AR3 with rubber gaskets, please observe the provisions of the standard DIN 7716 "Rubber products". Requirements for storage, cleaning and maintenance.
