WO2018025285A2 - Equipment for metal dowel checking - Google Patents

Abstract

The metal dowels applied with resin paste are used for the installation of machined parts and components in the manufacturing. Their characteristic allows to make fixing more simple and quick, if compared with the mechanical dowel. They need a careful installation due to the drilling hole diameter and they need the hole cleaning before applying the paste for fixing. Sometime, especially in the external sites, it may happen that some operations aren't performed according to the rules given by companies producing the metal dowel. Following of this analysis I have created this new type of equipment because the operator could have the necessity to verify the resistance of the metal dowel after the installation. On this basis, I have drawn this equipment to create a compact equipment that can be used in external sites. The equipment allows to apply a variable extracting force according to the external diameter of the threaded rod of the metal dowel or to the diameter of the internal threaded hole in the dowel. To obtain a variable strain force for the different dowel diameters a system is used with hydraulic control unit to vary the force easily. The working principle of the equipment is based on a shaft with adapter that is screwed on/in metal dowel on which the test of solicitation is performed; that can be the dowel at threaded rod or the dowel with internal threaded hole. This shaft must exert a force of traction on the metal dowel putting in pressure the internal chamber placed on the upper base of the piston. Pistons are equipped with the legs to make the reaction on the same surface where the dowel is applied. To make the external or internal screwing on the metal dowel it is necessary to divide the pull shaft into two parts: the first part is leaned on the fifth wheel and the second part is rotating, that can made at shape of turbine or at rotation flange bearing the toothed wheel. Both bring the adapter for screwing on the metal dowel. When the test of traction is needed, the second part that is rotating, is moved together with at the first part of the shaft.

Description

EQUIPMENT FOR METAL DOWEL CHECKING.

The present invention refers to an equipment for metal dowel checking.

The invention stems from the field of dowels with synthetic resin. The metal dowels are resistant to checks in laboratory, but they require during the installation the application of some rules technical. This project is based on the necessity to create a compact equipment, that can be used in the external sites of the firms to check the dowel after the installation.

The equipment is based on the principle of applying a variable vertical force to the final part of the metal dowel. This force must be equal to the maximum force acceptable for the checked type of dowel.

To obtain a variable force of stress of the dowel, it's necessary to use a hydraulic system that exerts a different value of forces in traction in relation to the diameter of dowel.

The invention, as claimed in claim 1, will be better described by some preferred embodiments thereof, provided as a non-limiting example, with reference to the enclosed drawings, in which:

Figure 1 shows the equipment of the invention in prospective view.

The below part of central body (ref. 6) is bolted to a ring with double threading (ref. 38) that brings a body (ref. 40) having an internal turbine by means of bearing, under it there is the adaptor (ref. 43) to be screwed to the metal dowel (ref. 60). In the figure a potential obstacle is placed between the equipment and the dowel (ref. 70).

Four prolongations (ref. 10), that everyone is placed on the side of the piston brought a leg (ref. 12), each exerts the force by means of the foots of support (ref. 24), It involves the spherical articulation (ref. 22) or on the iron block to allow an alignment of the equipment to the axis of action of the dowel.

The entrance of the oil (ref. 26 fig. 2) by means of two hydraulic pipe connections to keep in pressure the upper loading chamber of the piston to perform the positioning and the testing of pull of the dowel. The entrance of hydraulic oil (ref. 41) by means of the connection pipe at low pressure, is needed to recirculate the oil inside the turbine for screwing/unscrewing on the metal dowel. The oil pressure in both the two circuits is managed with the buttons placed on the central body (ref. 28 and 29).

The button of emergency stop (ref. 1) is placed over the equipment to allow the discharge of both circuits in case of necessity.

The position transducers (ref. 67) fixes on the support (ref. 68) detect the position of the leg (ref.10). Figure 2 it can be seen the upper view of the equipment with some references indicated in figure n°l.

In this view are visible the buttons (ref. 28) to perform the descent and ascent of the legs for positioning and the buttons (ref. 29) to perform the screwing and unscrewing of the adaptor on the dowel. The buttons are protected with lateral protections (ref. 63) by the movement of the legs (ref. 10).

This device is designed for two working situations. Firstly, it must be screwed/unscrewed to the metal dowel for a number of threads equal to the height of the tall nut and later there it must exert the pulling force equal to the maximum admissible load of the dowel.

Figure 3 shows the section view of the components that compose the equipment for testing the dowel with the following references."

The screwing on the dowel (ref. 60) of the adaptor (ref. 43) is performed with the entrance in one of the hydraulic connections (ref. 41) is unloaded of the switch (ref. 29) to create the recirculate of the oil inside the turbine (ref. 19), the other hydraulic connection (ref. 41) it's sent in unloading. The screwing is made until the proximity switch (ref. 21) detects the head of the metal dowel (ref. 60). The proximity switch is placed in a steel support (ref. 20). The resistance at the pressure of the surface of the turbine (ref. 19) is assured by means of two gaskets, one it's placed on the upper part (ref. 39), the other on the lower part (ref. 42). The blocking (ref 15) metal ring is placed on the bearing (ref. 16) to allow the independent rotation of the turbine from the central shaft (ref. 4). The bearing (ref. 17) centres the turbine body (ref. 19) at external body (ref. 40) that is attached at the body (ref. 6) by means of the ring with two threads (ref. 38).

The traction test is made with the entrance of the oil in the hydraulic connection (ref. 26) and a second connection is available (ref. 2 fig. 2) to have abetter distribution of the pressure on the surface of the cylinder or to apply a vent valve.

The oil is put in pressure in the upper chamber, that it's composed by the upper cover (ref. 5), the lateral surface (ref. 6), and the piston (ref. 30) to bring in position the legs composed with reference 10, 12, 22 or 56, 24, 25 at an intermediate position detect by mean of position transducers (ref. 67) (about 14 mm from end stroke) to allow the adjustable of the foot against the wall of countercheck. After it's putting in pressure on the lid (ref. 5) that is screwed on the central shaft (ref. 4). The pressure generates a traction force on the central shaft (ref. 4) that is leaded on the spacer (ref. 37) made of composite material type PCMW 426601.5. By means of threaded metal rings (ref. 36 e 35) the force is transmitted to the (continue description figure n°3) internal ring of bearing (ref. 17), the traction force is exerted by means of turbine (ref. 19) that puts the adaptor (ref. 43 or 44) in traction placed on the dowel (ref. 60 or 61) that can be a grub screw or threaded bush (see figure n° 12, 15). To avoid the unscrewing during the repetitive cycle, the threaded rings (ref. 36, 35) from the body of the turbine (ref. 19) the assembly is assured with two metal plugs (ref. 65 fig. 3 and 10) positioned on the lateral surface, placed when the assembly is made.

The connection of the legs (ref. 10) is made with the insertion inside of the seats of the piston (ref. 30) and it's kept in position with a metal plug (ref. 9). The initial part of the grub screw (ref. 12) is placed inside of the support (ref. 10) and at the end of the grub screw (ref. 12) is placed the spherical articulation (ref. 22 or the iron block ref. 56) with the function to unload the force on the foot of support (ref. 24). The polymer extent (ref. 25) is applied on the load foot a metal plug and screws.

The piston brings the legs (ref. 10) flowing inside the central body (ref. 6). A spacer in polymer reinforced (ref. 11) is interposed between the connection of the legs (ref. 10) and the piston (ref. 30). It has the function to prevent to the friction of the iron surface of the central body (ref. 6) with the connection (ref. 10) of the iron leg.

In case of necessity it's possible to activate the emergency stop button (ref. 1) placed on the upper lid (ref. 3) of the central shaft (ref. 4). The button of emergency stops every working procedure discharging all hydraulic circuits.

The piston (ref. 30) is centred on the external body (ref. 6) to slide with the driving seals of the piston (ref. 7) and the pressure of the piston is assured with the keeping gaskets (ref. 27). The piston (ref. 30) is guided on the shaft (ref. 4) by mean of the driving gaskets (ref. 8) and the pressure is kept with the gasket of seal (ref. 31). The gasket seal on the rod (ref. 32), it is needed to remove the impurity from the rod before the passage of the hydraulic gaskets seal (ref. 8, 31).

A spiral spring (ref. 14) in round wire serves to be placed in the high position of the legs at the end of the procedure with the decreasing of the pressure in the space over the piston. The spring is centred on the shaft (ref. 4) by means of a polymer spacer (ref. 13) kept in position with a metal plug.

If the switch of proximity XT1 M12 (ref. 34) is activated, it detects the subsiding of the metal dowel after having put in pressure the upper chamber of the cylinder during the stress test. The operation of the device.

The device has a system for screwing with turbine (fig. 3 ref. 19), it's joined with strain shaft (fig. 3 ref. 4) that works at low pressure and brings the adaptor for dowel (fig. 3 ref. 43, fig. 13, 14, 16, 17). It has a screw hole of diameter equal to metal dowel to test. The adaptor of dowel (fig. 3 ref. 43, fig. 13, 14, 16, 17) is screwed on a grub screw dowel fixed with resin anchor (fig. 3 ref. 60) for a height equal to the tall nut.

The turbine (fig. 3 ref. 19) is driven on the external diameter with a bearing (fig. 3 ref. 17) that reacts on the external shape for restraint (fig. 3 ref. 40), the pressure in the turbine is ensured by two radial seals for shaft Angst-Pfister for rotation body with shape AS named A+P RWDR, material NBR AP 70.12 cod. 10211010 placed over the turbine having diameter 110mm (fig. 3 ref. 39) and a seal (fig. 3 ref. 42) with shape AS named A+P RWDR material NBR AP 70.12 cod. 10204235 placed under the turbine body and acting on the central shaft.

The device for automatic screwing has the straight vanes of the turbine (fig. 3 ref. 19) for the necessity of having the reversible motion. Screwing is possible manually means of a monkey wrench on the machining created over the threads of the adaptor dowel (fig. 3 ref. 43, fig. 13, 14, 16, 17).

After putting the check device on the dowel (fig. 3 ref. 60), the operator pushes the button placed on the external body of the check device (fig. 2 ref. 29) to send in pressure the circuit of the turbine (fig. 3 ref. 19) screwing on the metal dowel until the switch proximity (fig. 3 ref. 21) notes the head of the dowel.

If the control unit detects a pressure increase in the circuit of the turbine, a valve intervenes to stop the introduction of the oil because dust can be present on the threads or the adaptor can be screwed in an incorrect way. During the screwing of the central shaft on the metal dowel (fig. 3 ref. 60), the legs are kept in raised position by means of a helicoidally spring (fig. 3 ref. 14) of diameter of 4 mm and external diameter of 54 mm. The mechanical characteristic of the spring is shown in figure n° 4.

Figure 4 shows the helicoidally spring identified with ref. 14 in fig. n°3. It can exert a variable force to raise the legs from 0 to PI = 355 N and it has the following technical datum:

The device performs the screwing on the dowel (fig. 3 ref. 60) with the turbine (fig. 3 ref. 19) connected to the adapter (fig. 3 ref. 43), it is stopped when the head of the metal dowel arrives at the end of the cap and it's activated the switch proximity of diameter 12 mm type XT1 12 SI PAL2 (fig. 3 ref. 21) placed on the shaft of stress (fig. 3 ref. 4). The central unit at the end of the procedure of screwing, prepares itself to put the oil on the upper space on the piston composed by elements ref. n° 5, 6, 30 of fig. 3.

In the equipment with the manual screwing is obtained acting on the lever (fig. 8, 9, 10 ref. 55) that puts in rotation the toothed wheels (fig. 8, 9, 10 ref. 53 and 52) and the operator must give a manual consensus to pressurize the second circuit.

The central shaft (fig. 3 ref. 4) performs the force of stress. It's centred on the turbine by means of SKF bearing 61808 2RS1 (fig. 3 ref. 16) and it has a series of spacers with threaded ring to place the shaft in correct position (fig. 3 ref. 15, 36, 35) they allow the shaft for the positioning and the rotation by means of a spacer in composite material type SKF PCMW 426601.5 E (fig. 3 ref. 37) and the inferior part of the shaft leans on fifth wheel SKF 51207 (fig. 3 ref. 18). To avoid the unscrewing during the repetitive cycle, the threaded rings (fig. 3 ref. 36, 35) from the body of the turbine (fig. 3 ref. 19) the assembly is assured with two metal plugs (fig. 3 ref. 65 and 10) positioned on the lateral surface, placed when the assembly is made.

The choice of the entity of the stress is made to act on the selector placed on the central unit, it varies the different pressure according to the diameter of the grub screw of the dowel (fig. 3 ref. 60).

The operator pushes the button (fig. 2 ref. 28) and gives the signal to make entrance of the oil in cylinder camera (composed with elements ref. 4, 5, 6, 30 fig. 3) put in low pressure. The loading foots of the device are advanced (fig. 3 ref. 10, 12, 22, 24, 25) until they lean at the wall or until the position transducers (fig. 3 ref. 67) detect a course of 14 mm (13 mm from the end of the buttonhole). Every loading foot with its threaded rod is adjustable bring it on leaning on the wall. The proximity switch XSl 18 B3 NAL2 (fig. 6 ref. 33), detects the position of the supports of the legs that it isn't under the value of 8 mm by the end of the buttonhole of the path of movement because if s the minimum value of course permissible before making the stress test.

If the proximity switch is activated, it signals the necessity to adjust the height of the load foot (ref. 24) or with the positioning of the extension in polymer under the foots of support (ref. 25). In case the proximity switches XT1 12 SI PAL2 (fig. 3 ref. 34) or XSl 18 B3 NAL2 (fig. 6 ref. 33) are activated, it's necessary to proceed with the elongation of the grub screws (fig. 3 ref. 12) acted on the bolts (fig. 3 ref. 57) placed before and after the legs (fig. 3 ref. 12) of support to stop the grub screw and replace the device.

The legs (fig. 3 ref. 12) are made with rods threads, the bolts are placed on it to allow the positioning of the rods threads along the axle of action. At end of the rods threads are placed the load foots (fig. 3 ref 24) by means of spherical articulation (fig. 3 ref. 22) to allow the better alignment of the device at the axle of the metal dowel also if it isn't perfectly perpendicular to the surface of the wall where it's leaning or with the iron blocks (fig. 3 ref. 56) placed with pin (fig.1 ref. 23) that allow a minor possibility of alignment at the axle of the dowel.

During the translation of the piston (fig. 3 ref. 30) the pressure maintaining on the lateral surface is assured by means of gaskets. They are:

♦ On the external side of the cylinder (fig. 3 ref. 30):

^● To maintain the pressure a gasket Piston Seal GRP cod. 11.6510.0250 in PTFE loaded (fig. 3 ref. 27) is placed.

^● The driving and the containment of the cylinder is made with gasket type GT code 11.6591.0030 of mat. PTFE CG.429-01 (fig. 3 ref 7).

♦ On the internal side of the cylinder are placed the gaskets that act on the centre shaft (fig. 3 ref. 4):

• To maintain the pressure is placed the gasket RPS cod. 11.6560.0525 (fig. 3 ref. 31).

• On diameter of 36 mm to drive the cylinder on the stem, there's a gasket type GT code 11.6591.0030 of mat. PTFE CG.429-01 (fig. 3 ref. 8).

• To perform the clean of the stem there is the gasket type BWA cod. 11.6574.0240 (fig. 3 ref. 32).

When the legs (fig. 3 ref 10, 12, 22, 23, 24) are leaned on the wall and without that support has activated the proximity switch diameter 12 mm (fig. 3 ref. 34) placed at the end of their path, the hydraulic central unit prepares itself to active the oil pump at high pressure if the position of the legs is between 14 mm by end course detects by the position transducers (fig. 3 ref. 67) and 8 mm detects by the position transducers and/or proximity switch (fig. 6 ref. 33).

For safety reason, it is necessary to give a manual consent pressing a button or two button to have both the hands pawned to avoid the tensioning with objects or the hand pinched between the surface under the foots and the area of thrust. The equipment is screwed on the dowel and it remains in position without the support of the worker. If it's necessary the support by the worker it must be activate a control on the central unit for second worker, that keep the buttons pulls on the switches (fig. 2 ref. 28 and 29). They are disable by the function of rotation and movement of the legs in the central unit, to have the safety that the worker doesn't have the hands in dangerous position.

At this point the device is placed and it' s ready to make the check. It sends oil to pressurize the upper chamber of the piston through the entrances (fig. 2 ref. 26) placed over the lid (fig. 2 ref. 5) of the cylinder, the pressure inside the chamber of the cylinder varies in base of the dimension of the metal dowel.

The stress check is made by maintaining the pressure for a short time (some second) and if the metal dowel resists all system must be stationary. In the eventuality, the dowel gives way the device goes forward of 8 mm minimum and it will go to end of the buttonhole course and it actives the switch of proximity XT1 12 SI PAL2 (fig. 6 ref. 34) and it signs at the central unit that the test of check the dowel has failed or with the detection of a course of 27 mm by means of the transducer position (fig. 5 ref. 67).

The working pressure "p" [MPa] of the device in the cylinder chamber is variable to have different "F_request" [N] forces and it's regulated in relation of the diameter "d" [mm] of the metal dowel.

The thrust area for exercitation of the force of the stress is obtained from the geometry of the

If the metal dowel hasn't the resistance of the force of stress, it remains inside of the seat for several millimetres and it keeps the device from the danger to fall down.

The connection of the machine with flexible pipe allows to reduce the weight of the device.

The foots of load have an important aspect, because they give the possibility to align the device to the axle of dowel, the surface of load is dimensioned for specific load of 5 N/mm².

In this study two different types of "foots" are made, in the final version of the equipment all attacks of foot will be identical.

The first type, shown in figure n° 5, has a spherical articulation SHCB 16 of SKF (fig. 5 ref. 22) that allows the alignment along two axles with an inclination of ±10 degrees compared to the theoretic perpendicular plan of the wall. Other type, see fig. 6 and 7, allows alignment along one axle while the second axle is fixed. If it's considered the possibility of rotation of the equipment and the width of the foot of lean combined with the possibility of elongation of every foot in independent way this solution can be considering acceptable.

Further, under every foot can be inserts the extension in polymer reinforced (nylon 6/10) (see figure 5, 6, 7 ref. 25). The aim is to give the possibility to check a dowel with a notable height out of the plane of the wall or to allow a configuration on measure of the application. Indeed, the Polymer reinforced is easily machinable in site on the polymer surface of support the foot, in case an obstacle is installed between the dowel and the device, it's only important to consider the reduction of the surface of lean with the consequent increase of the specific load.

Figure 5 it can be seen the section view of the equipment to check the metal dowel with legs composed by spherical articulation SIKB 16 SKF (ref. 22).

The extremity of the leg (ref. 10) is holed to allow the passage of the threaded rod to high resistance (ref. 12) that brings the load by means of the spherical articulation SIKB 16 (ref 22) screwed on it. The bolts (ref. 57) placed over and under the extremity of the leg have the function to adjust the position of the height of the legs.

In the centre of the eye of the spherical articulation is placed the pivot (ref. 23) locked with seeger ring (fig. 8 ref. 47) to prevent the unthreading but in this section the reference n°47 isn't seen. The joining of the load foot (ref. 24) to the spherical articulation (ref. 22). At the base of the support foot are fixed the extension leads in polymer reinforced (ref. 25) by means of a screw of fixing (ref. 48). The metal plug (ref. 49) is fitted in the centre of the extension in polymer reinforced (ref. 25) for centring in the middle of the load foot (ref. 24). The locked system foresees a metal plug (ref. 49) to take the possible transversal forces. The reference n°45 shows the device against the rotation applied on the body of the turbine (fig. 3 ref. 19), it serves to prevent the unscrewing of the adaptor (ref. 43 or 44). Against the rotation is locked with three screws (ref. 46), one screw is screwed on the body of the turbine and two screws make the countercheck on the hexagon part of the adaptor for dowel (ref. 43 or 44).

Figure 6 shows the lateral view of the equipment to check the metal dowel with legs composed by fixed support (ref. 56) screwed on threaded rod (ref. 12), it foresees the bushes on the pin (ref. 23).

In the figure can be seen some references of the figure n°5 with the exclusion of the reference n°22 replaced with the position n°56 that indicates the support of the legs. Figure 7 shows the view in section of the equipment to check the dowel with legs fixed on the support (ref. 56) screwed on threaded rod (ref. 12) that foresees the application of the bushes (ref. 58) on the pivot (ref. 23).

It's possible to see some references of the figure n°5. The reference n°22 fig. 5 is replaced with the reference n°56 that it shows the fixed support. The metal plug (ref. 49) is embedded in the extension in Polymer reinforced (ref. 25) and it's centred in the middle of the load foot (ref. 24).

This equipment is built in steel because some components work at high pressure, but some components are exposed to low solicitation that can be produce in special mechanical plastic. This combination of materials allows to arrive to a weight of about 16 Kg.

The device described in the previous pages can be realised with manual screwing and unscrewing to allow a simplification of the hydraulic central unit and the equipment.

The equipment with manual screwing (fig. 8) is different only for the first part regarding at the screwing or unscrewing on the metal dowel because this system replaces the hydraulic screwing but it's equal for the part of checking of the dowel and the description will be omitted because it is described in the previous pages.

This device uses a system of manual screwing or unscrewing by means of the toothed wheel and the pinion.

The toothed wheel is joined to the shaft of stress (fig.10 ref. 4) by mean of a rotate flange (fig. 10 ref. 51), on it is screwed the adaptor for dowel (fig. 10 ref. 43). The adaptor has a threaded hole of dimension equal to the diameter of the metal dowel by verified, it is screwed on the dowel (fig. 10 ref. 60) for a height equal at the tall bolt.

The rotation flange (fig. 10 ref. 51) is driven on the external diameter with a spherical bearing (fig. 10 ref. 17) that reacts on the external body of containment (fig. 8 and 10 ref. 59).

The device for manual screwing is composed by a toothed wheel at straight teeth (fig. 10 ref. 52) that receives the rotation motion from the pinion (fig. 10 ref. 53). The screwing is possible with the rotation of the lever (fig. 10 ref. 55) that is brought by bearing placed in the support (fig. 10 ref. 54). Further, in case an inconvenience occurs is possible to screw in manual way using a monkey wrench on the hexagon machining created on the rotation flange (fig.10 ref. 43, shown in fig. 13 or ref. 44 fig. 20 shown in fig. 16).

During the screwing on the adaptor of the dowel (fig. 10 ref. 60), the legs are kept in upper position through the helicoidally spring (fig. 10 ref. 14) when there is no pressure in the upper chamber of the piston. The manual screwing on the threaded of the metal dowel (fig. 10 ref. 60) is stopping when the threads arrive at the end of the adaptor (fig. 10 ref.43) with the signal from the switch proximity of 12mm XT1 12 SI PAL2 (fig. 10 ref. 21). The hydraulic unit prepares the pump at high pressure for introduction of the oil in the upper chamber composed by ref. n° 5, 6, 30 of fig.10. The following passages of the description are equal for the equipment with hydraulic screwing. The system is supervised by position transducer (fig. 9 ref. 67) to make the first course of adjustable the height of the loading foots with the stop of the lowering of it at 13 mm by end of buttonhole and the proximity switch XS1 M18 (fig. 9 ref. 33) (sensing distance 8 mm) for detecting the reaching of the maximum lower position of the legs, if it's activated before the test is need the repositioning of the legs with the lowering of the threaded rod (fig. 9 ref. 12) or with the inserting of the extension in polymer reinforced is needed. The equipment is ready to make the test. It sends the oil in pressure to the upper chamber through the hydraulic attack (fig. 10 ref. 26) placed on the lid of the cylinder (fig. 10 ref. 5), the pressure inside of the chamber is variable based on the dimension of the dowel.

The check of stress is made by maintaining the pressure for a short time (some seconds) and if the metal dowel resists the all system must be stationary. In the eventuality that the dowel gives way, the device goes forward of 8 mm minimum and it will go to end of the buttonhole course and it will active the switch of proximity XTl 12 SI PAL2 (fig. 8 ref. 34) and it signs at the central unit that the test of checks the dowel has failed.

The working pressure exerted in the chamber inside of the cylinder allow to perform a solicitation of stress "T" that is regulated by varying the value of pressure on the hydraulic control unit.

If the test fails the dowel stays inside its side for a length of several millimetres and it keeps the machine of the test from the fall down.

The connection of this type of equipment of test is realized with less numbers of flexible pipes in comparison to the equipment with hydraulic screwing.

Figure 8 shows the frontal view of the equipment with manual screwing.

The central body (ref. 6) brings the support (ref. 54) of the lever (ref. 55) complete of bearings. At the extremity of the lever is placed a pinion (ref. 53) that receives the rotation motion from the lever (ref. 55) and meshes with the toothed wheel (ref. 52) placed on the axle of the central shaft. The toothed wheel is fixed at the rotation flange (ref. 51) placed with the bearing and on it is screwed the adaptor of the dowel (ref. 43) on which the test is performed and where it's possible to find an obstacle (ref. 70). (continue description figure n°8) The hydraulic attack (ref. 26) serve to send the pressurised oil to the upper chamber of the piston and for performing the test on the metal dowel. The legs of positioning are composed by four prolongations (ref. 10) inserted in the holes of the piston and everyone have a threaded rod (ref. 12) adjustable with bolts and at the end is placed the spherical articulation (ref. 22 or the block in iron (ref. 56) bring the foot of load (ref. 24) that downloads the pull force.

Figure 9 shows the frontal-inferior view of the equipment with manual screwing with some references of figure n°8.

In figure with ref. 22 indicate the first type of the two-different typology of the four load foots to exercise the reaction force of the pull. It's complete of the spherical articulation (ref. 22) and the pin (ref. 23) is placed inside of it and it supports the load foot of support, this system allows an alignment of the equipment at the axle of the dowel.

In figure with ref. 56 indicate the second of the two-different typology of the four load foots for exercising the reaction force of the pull. It is completed of the support screwed on the threaded rod.

The metal dowel (ref. 60) is hidden of the encumbrance (ref. 70).

The button of emergency stopping (ref. 1) sends both hydraulic circuits in discharge.

The button (ref. 28) serves to get on and off the legs before of the test of pull. An unscrewing device of the adaptor (ref. 43) is fixed on the rotating flange (ref. 51) and it is load-bearing of the toothed wheel (ref. 52). When the circuit at high pressure is active the button (ref. 28) is disabled by its function, if in the unit control is activated the presence of the second worker, the buttons (ref. 28 and 62) have a safety function to avoid that the man has the hands in dangerous position.

Figure 10 shows the view of the equipment to check the metal dowel with manual screwing. His functioning for the test of pull is equal to the device shown in figure n°3 whence are removed the components for the hydraulic screwing (fig. 3 ref. 39, 40, 41, 42) and the ref. 19 is replaced with ref. 51 that indicates the rotation body centred on the external body (ref. 59) by means of bearing (ref. 17) for the rotation of the adaptor (ref. 43 or 44), it takes the rotation force by the toothed wheel (ref. 52).

Figures are added with respect to the figure n°3. The lever (ref. 55) brings in rotation the toothed wheel (ref. 53) that meshes with the pinion (ref. 52) fixed to the rotation flange (ref. 51) by means of screws and metal plugs. The rotation flange supports the adapter (ref. 43) of the metal dowel. The hydraulic central unit has a function of management of the operations and storage the data. This equipment is studied for two different types of metal dowels and before using the equipment is important to select the type of dowel on which the check is performed. The two types of dowels that can be checked are:

♦ Metal dowel with threaded rod is positioned in the hole made in cement structure fixed with phial in resin (see figure n°12).

♦ Metal dowel with internal threaded rod, where inside of it is placed the screw to take the load (see figure n°15). In this verify is excepted the proximity switch XT1 12 SI PAL 2 (fig. 10 and fig. 3 ref.21) placed inside the adaptor bearing body because in this case is impossible to check the screwing of the adaptor in the dowel. The checking of the screwing of the adaptor is possible only with visual inspection.

On the body of the equipment are applied the buttons for the management of the functions in low pressure:

♦ A button allows the descent of the foots (fig. 2 ref. 28).

♦ A button allows the ascent of the foots (fig. 2 ref. 28) and when it's disabled by its function, it has the function of safety to avoid that the second worker has the hand in dangerous area.

♦ A button allows the clockwise rotation of the turbine (fig. 2 ref. 29).

♦ A button allows the counter clockwise rotation of the turbine (fig. 2 ref. 29) and when it's disabled by its function, it has the function of safety to avoid that the second worker has the hand in dangerous area. In the equipment whit manual screwing the function of safety, it's made by mean of the button (fig. 8 ref. 62).

Further a button of emergency switch (fig. 2 ref. 1) is placed over the equipment. In this position, it is possible to activate it with the hands or with the bust of the worker because during the work the position of the equipment is between the arms of the worker.

A console placed on the hydraulic control unit allow the management of the equipment with the follow functions:

♦ A button allows the descent of the load foots by sending the oil in low pressure in the upper chamber of the piston.

♦ A button allows the ascent of the load foots putting in discharge the upper chamber of the piston.

♦ The buttons of commanding of the force in the circuit at high pressure to make the test of pull because it isn't possible to give this command by the body machine for safety reason. ♦ The button for activing the presence of second worker that it uses the buttons (fig. 2 ref. 28 and 29 or fig. 9 ref. 28 and 62) place on the equipment when for safety reason are disabled by their functions because high pressure circuit is active.

Figure 11 shows the hydraulic diagram of the control unit

In the hydraulic diagram of the equipment to manual screwing is omitted the part of diagram (indicate whit stretch line and point and annotation "BB") for force-feed about the screwing and unscrewing.

Annotation "A": Micro switch XS1 M12 fitted on the pulling shaft. It closes when the metal dowel with rod threaded is screwed into the female adapter. It's disabled leaving the valve in open position for the unscrewing and for the test with adapter for dowel at internal threaded hole. (fig. 3 and 10 ref. 21)

Annotation "B": Turbine for screwing (fig. 3 and 20 ref. 19)

Annotation "C": Micro switch XSl M18 (fig. 6, 7 ref. 33), when is closed the central unit stops the legs lowering.

Annotation "Dl": Pressure switch detects the value of the pressure in the chamber equipment. If it's over 0,7 atm, it allows the activate the high pressure in circuit of pulling test by means of the electro valve "H" and it prevents to activate the unscrewing circuit (annotation "BB") because the legs are in leaning on the wall by means of the electro valve "P". If the pressure value is equal at 0 atm on pressure switch "Dl" by means of the electro valve "F' allows to activate the screwing circuit (annotation "BB") and it disables the circuit at high pressure.

Annotation "D2": Pressure switch detects if there's an increasing of the pressure in screwing circuit makes a comparison with the value set up at the electro valve "T". If the value detects is upper at the maximum value admissible by means of the electro valve "P" and/or the command " J2" disables the rotation because can problem on threads.

Annotation "E": Pressure gauge on the pressure in the chamber equipment- Annotation "F": Cylinder for pulling test (fig. 3 and 10 ref. 30)

Annotation "G": Electro valve controlled by proximity switch XSl M12 fitted on the cylinder body. (fig. 3, 8 ref. 34). It discharges the oil in pressure if the metal dowel doesn't resist at the pull strain test.

Annotation "H": Valve activates by the Pressure switch indicated in the scheme with note "Dl". If in the cylinder "F" there's a pressure major of 0,7 atm, it means the loading foot are leaning on the wall without to active the proximity switch annotation "C" or with a position (continue description figure n°l 1 annotation "H") of the legs at course of 19 mm (8 mm by finish course) detects by position transducer (fig.l ref. 67).

Annotation 'Τ': Pressure regulating valve for equipment legs lowering. It works with two different value of the pressure. One value of the pressure is 0,76 atm and the second value of the pressure is 0,42 atm. Theoretical flow: 1 1/min.

Annotation "J": This electro valve is activated if the micro switch (fig. 3 and 10 ref. 21) is closed. Or the unit control must activate it to allow the passage of pressurised oil in pressure if the micro switch (annotation "A") is disabled for test on metal dowel at internal rod. It's also used to stop the lowering of the foots when the position transducer (fig.1 ref. 67) detects the value of 14 mm of course to allow at the worker to adjustable the position of the loading foot leaning on the wall and it's activing when the worker pushes for the second time the button (fig. 2 ref. 28) for lowering the foots.

Annotation "J2": Both the electro valves insert to bring and go out the pressurised oil by the group turbine must close the supply of the pressurised oil if the pressure switch "D2" detect a value upper at the maximum value admissible and when the operation of screwing is finished.

Annotation "K": Valve of regulation the flow of the discharge oil.

Annotation "L": Switch for lowering the legs (fig. 2, 3, 10 ref. 28) and when it's disabled by its function, it has the function of safety to avoid that the second worker has the hand in dangerous area.

Annotation "M": Switch for climbing the legs (fig. 2, 3, 10 ref. 28).

Annotation "N": Switch for screwing (fig. 2, 3 ref. 29).

Annotation "O": Switch for unscrewing (fig. 2, 3 ref. 29) and when it's disabled by its function, it has the function of safety to avoid that the second worker has the hand in dangerous area.

Annotation "P": Valve closes if there's a pressure in the pressure switch (indicate with annotation "Dl").

Annotation "Q": Switch for oil supply in high pressure to make the pulling test. For safety, the second work man, that it holds the equipment in case the equipment is placed in vertical position with head under (invert position) or in horizontal position, he must keep pushing the buttons "L" and "O" that are disabled by hydraulic unit control because it is activated the high-pressure circuit This precaution serves to be secure that the man worker doesn't have the hands in dangerous position.

Annotation "R": Hydraulic compressor unit. (continue description figure n°ll)

Annotation "SI": Flow regulating valve in the turbine. Theoretical flow: 5,4 1/min

Annotation "S2": Flow regulating valve in the cylinder for lowering the loading foot with theoretical flow: 1 1/min

Annotation "T": Automatic pressure regulating valve. It supplies the pressure inside the turbine for screwing and unscrewing

♦ The values of maximum pressure for screwing and unscrewing on the dowel at rod threaded are indicated in table n° 5 in reference to the diameter.

♦ The values of maximum pressure for screwing and unscrewing on the dowel at internal threaded rod are indicated in table n° 15 in reference to the diameter.

Annotation "U": Emergency valve fitted on the equipment (Fig. 2, 3, 10 ref. 1).

Annotation "X": This electro valve is activated by the pressure switch "annotation Dl" for stopping the discharge of the oil at the value of 0,8 atm to avoid the raising of the legs during the discharge of the circuit at high-pressure.

Annotation "V": Fluid reservoir with the maximum pressure value of 120 atm.

Annotation "W": Switch discharges the oil in pressure after the pulling test, it's activated in automatic way because the dowel on which is made the test must resist at the pulling stress for a prefixed time, before of the pressure discharge. When pressure switch "Dl" reaches the value present in the regulating valve (± 2%) annotation "Z" a timer is activated which prevents the button from being operated (electro valve annotation "X") not before the prefixed time.

Annotation 'Ύ': Electro valve allows the discharge the oil with the button on the body equipment when there's a lower pressure at value of 0,8 atm detects by the pressure switch "Dl". It must be activing by hydraulic control unit after pull strain test to high pressure. Annotation "Z": Automatic pressure regulating valve. It supplies the correct value of the pressure inside the pulling cylinder

♦ The values of maximum pressures for pulling test on the metal dowel at rod threaded: "class 5.8 are indicated in table n° 8 in relation with the diameter.

•class A4-70 are indicated in table n° 9 in relation with the diameter.

♦ The values of maximum pressure for pulling test on the metal dowel at internal threaded rod:

•class 8.8 are indicated in table n° 18 in relation with the diameter,

•class 8.8-A4 are indicated in table n° 19 in relation with the diameter. Tests on metal dowels at threaded rod illustrate in:

Figure 12 shows the metal dowels with threaded rods applied with paste in resin.

Figure 13 shows the adaptor for metal dowels with threaded rods.

Figure 14 shows the section view of the adaptor for metal dowels with threaded rods.

To make the check on the metal dowels at threaded rod (fig. 12) the control unit must start the test with the request of setting the type of dowel and the diameters of it. The metal dowel can be at threaded rod or at rod internally threaded with rim.

The operator acts on the button place on the equipment body for management of the screwing. The control unit gives a variable pressure for every diameter of dowel, if every switch proximity is open.

If the switch proximity XTI 12S1 PAL2 placed inside the adaptor (fig. 3 and fig. 10 ref. 21) is closed, it's possible there are some problem because if there isn't a dowel screwed it must be opened.

If the switches proximity XTI 12S1 PAL2 (fig. 6 or fig. 8 ref. 34) XS118B3NAL2 (fig. 6 or fig. 8 ref. 33) placed out are closed, the loading foot can prevent the screwing.

The procedure of screwing is made sending pressurised oil to an entry of the turbine (fig. 11 annotation "B") and with the second connection of the oil in discharge. With this system, it's possible to create a circulation of pressurised oil without increasing the pressure. This procedure finish when the adaptor is screwed on the thread of the dowel, and it is got to the bottom of the adaptor activing the proximity switch XTI 12S1 PAL2 (fig. 3 and 10 ref. 21, fig. 11 annotation "A").

If it's detected (fig.11 annotation "D2") a raising of the pressure in this circuit, the worker must verify that the adapter (in figure n°13 e 14 it's possible to see the different typology) has been screwed for a necessary number of threads because an increasing of the pressure can be due to impurities on the threads. It could happen if it wasn't made a correct cleaning of the threads before the beginning of the procedure. To reduce the frictional between the threads, it is important lubricate them before the screwing the adaptor on the dowel.

The pressure of oil for screwing has been calculated to exert the screwing on base of the number of threads in taken of the metal dowel at threaded rod (fig. 12), that must be equal to the number of threads of the high nut ΌΝΙ 5587 EN 24034. In the following table are written the height of the nuts, that are divided into the threading step obtaining the numbers of working threads:

Calculating the development of the surface in contact in the thread for every screw. The height of contact for every screw is given from the normative (fig. 18) and it has this value:

♦ H1 - (5/8)*H where H is the total height of the threads and it's equal at:

♦ H = 0, 86603 *step of screw

and HI has the value of Hl= 0,54127* step of threads.

The surface of threads is inclined of 30° because the corner of thread has the value of 60°. The development of the threads is: Development

The thread has a circular annular development with a mean radius equal to the value of

we can get the total

surfaces of sliding, that they are summarized in this table:

In the calculation of the sliding frictional force between the surfaces in iron is used this value:

♦ Friction between steel and Dry steel has the "μ" value of 0,2→ 0,3

♦ Friction between steel and lubricate steel has the "μ" value of 0,15 ·

Considering that:

Force necessary movement = Force of pressing * μ

Force necessary movement— Superface of sliding * pressure * μ

Force necessary movement = (Superface of sliding * u.) * pressure

In the following calculations will be put the value of 1 N/mm² and at the end of chapter will be analysed the meaning of this value.

From which we have:

Moment necessary at movement— (Force necessary at movement * Medium radius) In the following table are reported the force values and the request moment for screwing. It is lower of the tightening torque that requests the deformation of the pieces to avoid the unscrewing.

♦ The calculated moment is constant and it is equal at the moment supplied from the blading of the turbine (fig. 3 ref. 19) that it has dimension's geometries of external diameter of 110 mm, internal diameter of 42 mm and height of blading of 31 mm.

Whence we have calculated the medium radius of action of the thrust oil on surface:

The request moment is calculated with division of the medium radius of the turbine that it's value of 38 mm. This operation gives me the value the force exercised on the blading (fig. 3 ref. 19).

To obtain the necessary force for the different threads and it's divided for the surface of every blading (fig. 3 ref. 19). They are obtained the different values of pressure for every diameter of thread.

Those calculations have generated the follow table to every diameter of the thread (fig.12):

The maximum working pressure for screwing is 0.5 bar for screwing the metal dowel to rod M24, M20, Ml 6 and for other threads are advisable a pressure value with sliding frictional equal to no more than twice the pressure needed with sliding coefficient equal at μ = 0,3 because it means a coefficient of μ = 0,6. That means that during the screwing the threads can be seizure. This table reassumes those calculations:

In this section is analysed the value of "p" (working pressure) equal at 1 N/mm² and in both the formulas the function (cos 30° ) serves for obtain the vertical force exerted in perpendicular way at the surface.

It's multiplied for the surface of the thread at the start of the screwing, it's equal to:

The following calculations consider the minimum working pressure in the turbine (fig. 3 ref. 19) with frictional coefficient between the threads equal to μ=0,3. It's a theoretical situation where the difference of pressure between the calculated nominal value and that it's written in the maximum value can be used for increasing the push force or for increasing the frictional coefficient. We calculate the value of p= working pressure =1 N/mm² for the different admissible forces of the different diameters of the threads.

The calculation of the flow in litres to minute of the hydraulic central unit necessary are obtain with the analysis of the volume between the blading multiplied the number of rotation the turbine (fig. 3 ref. 19) necessary for screwing the adaptor (fig. 3 ref. 43) on the metal dowel. In medium are necessary 10 rotations for screwing the threads of the adaptor (fig. 3 ref. 43) on dowel. This operation is delicate, especially for the threads with step equal 1 mm in this study has been privileged a slow rotation at the value of 20 rotations for minute.

♦ The size of the geometries of the turbine (fig. 3 ref. 19) have the external diameter of 110 mm, the internal diameter of 42 mm and the height of blading of 31 mm.

Obtaining an average area between the blading equal to 867 mm² it's multiplication for the height of 31mm obtaining a volume of:

♦ Area between the blading * height = 867 mm² * 31 mm =26877 mm³

The turbine is divided into 8 spaces among the blading and it performs 20 rotation to minute, it's possible to obtain the necessary flow for minute:

♦ Volume between the blading * n° space among blading * n° rotation to minute = • 26877 *8 *20 = 4300320 mm³.

Considering a yield η = 0,8, it's possible to obtain the flow request at the hydraulic control unit for screwing: * Theoretic flow / η = 4300320 / 0.8 = 5375400 mm³/minute = 5,4 I/minute

When the hydraulic central unit receives the signal the contact proximity switch XT 1 12S1 PAL2 (fig. 3 ref. 21 and fig. 11 annotation "A") is closed and it gives the signal to close the first circuit by means of the hydraulic valve. It is maintained closed to avoid the unscrewing from the metal dowel.

The operator activates the buttons (fig. 2 ref. 28) over the body of the equipment and it sends a low pressure inside the second circuit to put a low pressure in the chamber of the upper cylinder. The pressure must have the power to win the spring force (fig. 3 ref. 14), variable between 0 to 355N, plus the force to allow the descent of the group of load foot.

The pressure exercises are of two value regulated by mean the electro-valve (fig. 11 annotation "I"), the first value is less high than the second because in the first time between the position transducers (ref. 67 fig.l) is made a lowering of the loading foot (fig.l ref. 24) of 13 mm to obtain this course the helicoidally spring (fig. 3 ref. 14) is less compression (the length is 46 mm) with a request of 262 N. At this value is added a value of 100 N to win the frictional force. In this case, the pushing area is obtained from the geometry of the system by mean of the

When is applied this pressure value there is a first lowering the loading foot until the position transducers (ref. 67 fig. 1) detects a course made of 13 mm to allow at the worker to adjustable the loading foots leaning on the wall by mean of the nuts (fig. 3 and 10 ref. 57) and when the worker pushes for the second time the button (fig. 2 ref. 28) it's increasing the pressure at the second value. The pressure is calculated of positioning the loading foot in lower position because it must be capable of compress the spring until at the value of 27 mm. At this value is added a valu

to win the frictional force:

The foots go down and they load on the wall where is place a metal dowel to check. The load- bearing foot (fig. 10 ref. 33) can't activate the switch proximity switch of 18 mm diameter XS118B3NAL2 (fig. 6 ref. 33) and in case it's activated it's request a new adjustable of the position of the loading foot because the remaining free course of 8 mm must be kept to perform the pull's test. Or it's detected a rise of the pressure in the upper chamber by hydraulic control unit when the foots (fig. 3 and 10 ref. 24 and 25) are leaning on the wall.

The foots of the equipment must be leaning on the wall because otherwise the pressure transducer (annotation "Dl" in the hydraulic scheme of fig. 11) doesn't give the consensus to put the high pressure in the circuit. In case the loading foots (fig. 3 and 10 ref. 24 and 25) aren't in contact, it's necessary to proceed with their repositioning.

Positioning the loading foot, the equipment is ready for the pull check, if it isn't activated the micro XT1 12S1 PAL2 (fig. 6 and 8 ref. 34) placed at the end of path of the cylinder.

The stroke upper to the position of 8 mm by the end of the path of the load-bearing foots is needed serve for the repeatability of the tests because with an identical assembly of the dowel, it's possible to do the test again without adjusting the position of loading foots. Also during screwing, without the high positioning, it's possible that there foots leaning (fig. 3 and 10 ref. 24 and 25) on the wall prevent the adaptor (fig. 3, 10, 19 ref. 43) of screwing on dowel.

The operator puts the equipment on metal dowel, it can leave of the equipment and it can activate the buttons of the console of the hydraulic central unit, everyone with a different hand, and it can start the pull test the dowel. If the equipment is in a particular position is necessary a second work man because he holds the equipment in case is placed in vertical position with head under (invert position) or in horizontal position, he must keep pushing the buttons annotation "L" fig. 11 (fig. 2 ref. 28) and annotation "O" fig. 11 (fig. 2 ref. 29) that are disabled by hydraulic unit control because the high-pressure circuit is activated. This precaution serves to prevent harmful injuries to the worker' hands, option that can disable by the unit control if the equipment works in normal position. The test starts by pulling and maintaining for a few seconds the dowel in pull by means of the high pressure exercised inside the chamber of piston of the equipment. If the dowel remains in position whit out movement when the high pressure is taken out of the circuit, the central unit signals the correct execution of the test.

The table shows how to calculate the working pressure to make the test on metal dowel:

The values shown in the previous table are the maximum pull values to which is the dowel submitted. In some applications, the metal dowel can be installed for a value of solicitation less than maximum of solicitation offered by the product. It's good to foresee a possibility of inserting a value of solicitation that can be submitted to the dowel by which automatically is calculated the value of the working pressure of the equipment. The value of solicitation request must be always inferior to the value at the maximum value the metal dowel can support.

Instead, in case the dowel doesn't resist at the solicitation the dowel advances with a reposition of the equipment at 8 mm of distance and the support of the loading foot activates the proximity switch of diameter 12mm XT1 12S1 PAL2 (fig. 7 and 8 ref. 34) that shows the failed test of the dowel.

The central unit storages the following items of the data on an e-prom and/or can print a report for every tested dowel:

Test n°: -> Progressive Number of the test, is given in automatic way by the central unit. Type of metal dowel: -> It's selected by a manual selector on the hydraulic control unit, in this case is the dowel a threaded rod or but might be a rod with hole internal threaded.

Metal dowel test: -> diameter of the external threads of the metal dowel or the diameter of the internal threads hole at the dowel (fig.l2 and 15). It's the object of the test and it is given at start of the procedure.

Type of control on the screwing: -> It can be automatic with the proximity (fig. 3 and 10 ref. 21) or to be visualized with inspection of the worker (this function serves in case of anomaly or damage at the dowel to have the sequence and types of the operations made by the worker). Value of the solicitation of the test at the metal dowel: -> It's given by the elaboration of the previous date or it's obtained by the pressure exercised during the test.

Result of the test: -> If it hasn't been activated the proximity switch of diameter 12mm (fig. 3 and fig. 8 ref. 34) the result of the test is positive, if the proximity switch has been activated of diameter 12 mm, or the result is negative because the metal dowel hasn't resisted at the stress test.

At the end of the test it's possible to mark the dowel with a seal so that to ensure the check performance.

At the end of the test is better to discharge away the high pressure from the upper chamber maintaining the minimum value to guarantee the support of the loading foots because otherwise the helicoidally spring (fig. 3 and fig. 10 ref. 14) might raise the loading foots. In this way, it is possible to reduce the overloaded at flex of the threaded rod or of the threaded adaptor to avoid the falls at the equipment in case the metal dowel doesn't have resisted at the test and it can support the weight of the equipment. When the pressure is lowering at the minimum value of 0,8 aim the buttons (fig. 2 ref. 28 and 29 or fig. 9 ref.28) are reactivated.

The worker, that supports the equipment, might take off the pressure in the upper chamber acts on the button (fig. 2 ref. 28 and fig. 9 ref. 28) to allow the raising of the loading foots by mean of the helicoidally spring (fig. 3 and 10 ref.14).

The operator with the action of the buttons (fig. 2 ref. 29) on the body machine might start the procedure of unscrewing doing entrance the pressurised oil in the turbine in the connection that was the connection of discharge during the screwing. While the connection that during the screwing was for the oil entrance in pressure during the unscrewing is sent in discharge. The unscrewing is made without increasing the pressure if there isn't problem of friction on the threaded and it is finished when all threaded are unscrewed and the equipment can be extracted. In the equipment, the manual unscrewing is obtained acting on the lever (fig. 9 ref. 55) that puts in rotation the toothed wheels (fig. 9 ref. 53 and 52). For checking the dowel at rod with internal threaded hole to fixe with glue in resin, it's needed to take away the object placed in front because the hole made on the object is smaller than diameter of the dowel (fig. 15), with the consequence that the force of the traction applied by the device can be divided up on others dowel or react with the object placed in front of dowel. In this situation, the hydraulic unit control must supply a clamping force inferior to the couple of tightening. The adapter is screwed in the dowel and it's necessary that the operator will check visually the screwing complete of the adapter (fig. 16). He will give a consensus before making the check of traction.

Figure 15 shows the view of the different types of metal dowels at rod with internal threaded hole, they are applied with glue in resin.

Figure 16 shows the view of the different types of adapters for metal dowels at rod with internal threaded hole.

Figure 17 shows the view in section of the different types of adapters for metal dowels at rod with internal threaded hole.

The hydraulic control unit can demand at the operator the external diameter of the dowel in exam and by this data the central unit obtains the internal diameter threaded hole that is the diameter of the screw inserted or ask directly the diameter of the screw screwing in the hole threaded.

The operator manages the screwing acting on the buttons placed on the body (fig. 2 ref. 29 and fig. 19) of the equipment to check the metal dowel . The control unit checks that the two switches proximity aren't closed (fig. 19 ref. 33 and 34) and the position transducer in a position between 0 and 5 mm of course (or 27 and 22 by end of the buttonhole on the central body (fig. 19 ref. 6). If the check is positive, the unit control gives a variable pressure in referring to the screw diameter of the adapter (fig. 16) screwed in the dowel in exam.

The switch proximity XT1 12S1 PAL2 (fig. 20 ref. 21) place of inside the adapter is excluded. If one of the both the switches proximity XT1 12S1 PAL2 (fig. 19 ref. 34) or XS118B3NAL2 (fig. 19 ref. 33) is closed, it's possible that the loading foots (fig. 19 ref. 24) are leaning. They can prevent the screwing.

The operator activates the buttons (fig. 19 ref. 29) of the equipment and it starts the procedure of screwing with the entrance of the pressurised oil in the turbine and it puts in unload the second connection. It generates a circulation of pressurised oil without significant elevation of the value of the pressure. This procedure is finished when the adapter (fig. 19 ref. 44) is leaning on the border of the dowel. When the adapter (fig. 19 ref. 44) leans on the metal dowel it creates a raising of the pressure inside the blading of the turbine until at the maximum value admitted in relation to the screw adapter diameter placed inside the dowel, (with maximum value of 0,5 bar ~ atm for rod with internal threaded hole M 20, Ml 6 detect by annotation "D2" fig. 11). The metal dowel at rod with internal threaded hole (fig. 15) is checked at value of the resistance force of traction of the screw. The adaptor is screwed for a length of upper at those

M_aximum requested for screwing, this value allows a better distribution of the strain on threads. The operator must check the adapter (figures n° 16 and 17); if it is being screwed for numbers of threads necessary because it's possible an increase of the pressure of screwing due to the settle of dust on the threads because it hadn't been cleaned before starting the procedure.

Figure 18 shows the schema of the geometry of the threads, the value of this geometry is the base of the calculation of the method to obtain the value of Hl= (5/8) * H where H = 0,86603 *step of screw. "H" is the total height of the threads.

The oil pressure exercises during the screwing and it's based on the number of threads in taken in the rod with internal threaded hole, it corresponds at the maximum numbers that can be screwed in the threads of the dowel to avoid damages during the test. In the following table are reported the data of height and number of threads in taking:

The value of development of the surfaces in contact of the threads of every screw, is obtained by the normative with reference figure n°18 and its description where HI has the value of:

The surface has the thread inclined of 30° because the thread has at angle of 60° and the development length of a thread "Development

The thread has a development to form of circular crown with medium radius equal at the value of total surface of sliding:

That it's reassumed in this table:

in iron:

Force necessary oimoviment = Surface of frictional * pressure * μ

Force necessary oimoviment— (Surface of frictional * μ) * pressure

If the pressure value equal to 1 N/mm², the meaning of this value is analysed afterwards.

We have that:

Force necessary of moviment = (Surface of frictional * u) * 1

♦ In the equation is put μ = 0.3 from which we have:

The moment necessary for moving = (Force necessary moving * Medium Radius) In the following table are reported the value of the force and the requested moment to screw that will be inferior the lightening torque because it requests a little deformation of the components.

Those values are synthesized in the following table:

The rotational moment is constant during the screwing and it will supply by the geometry of the blading (fig. 20 ref. 19) that they have this value:

External diameter of 110 mm, Internal diameter of 42 mm and Height of blading of 31 mm From this geometry, it's possible to calculate the medium radius of action for give the push with the oil on the blading of the turbine (fig. 20 ref. 19):

The value of the requested moment for the screwing is calculated with the medium radius of the turbine equal at 38 mm. The force that must be exercised on the blading (fig. 20 ref. 19) is:

The force obtains is needed for screwing all threads and it is divided for the surface of every blading, in this way the different pressures of work for the different diameters of threaded are calculated.

All these data are collected in this table for the several diameters of thread:

The working pressure for screwing with maximum value of the pressure to 0.5 bar for M20

M16, while for every other diameter of dowel is advisable at a pressure no more than twice that calculated with frictional coefficient equal to μ = 0.3 because it means a value of μ = 0.6 that it's like bring in rotation the seized threads. These values are summaries in this table:

previous formulas. In the both follows formula the function (cos 30° ) serves for obtain the vertical force from the force perpendicular at the surface of sliding. When it's multiplied for the surface of one thread gives the vertical value admissible at start of the screwing.

If it's multiplied for all threads surface in taking, it gives the maximum vertical value

The following calculations consider the working pressure in the turbine with a frictional coefficient between the threads equal to μ=0,3. This situation is theoretical and the difference of pressure between the calculated rated value and the supplied serves to compensate or to increase the force of pushing or the coefficient of frictional. In the follows table are written the values of maximum vertical force admissible for given for

every value of the diameter of threads.

The calculating of the flow per minute supplied by the hydraulic control unit is obtained by the analysis of the volume between the blading of the turbine (fig. 20 ref. 19) and the number of rotations per minute.

The adapter to screw the threads must make, in medium, between 10 and 20 rotations. It's a delicate operation in particular for the threads whit step of 0,5 and 0,75. For this reason, during the design is being forecast a slow rotation at the value of 20 rotations per minute.

Knowing the geometry of the turbine (fig. 3 ref. 19), the average area between the blading of turbine is 867 mm² that it's multiply for a height of 31mm obtaining the value of:

Area between the blading * height = 867 mm² * 31 mm =26877 mm³

The turbine is divided in 8 space and it must perform 20 rotation for minute. With this information is possible to obtain the flow need to minute:

Volume between blading of turbine * n° spaces * n° rotations to minute =26877 * 8 * 20 = 4300320 mm³.

With the application of a coefficient of efficiency of η = 0,8

It's possible obtain the flow requested at the hydraulic control unit for screwing:

The hydraulic control unit close the circuit of screwing at the reaching the maximum effort to the screwing by means of the hydraulic valves. The signal closes both the connection of entrance and of exit of the circuit, to avoid the unscrewing.

Figure 19 shows the operation of the device (ref. 44) to check the rod with internal threaded hole. In the figure is possible to see some references of the figure n°l with the replacement of the reference n°43 with the other adapter for dowel ref. 44 (fig. 16 and fig. 17). The switch proximity places to internal the shaft of pull is disabled (fig. 20 ref. 21).

Comparing with the figure n°l there are additions of the ref n°45 that is the device of against the unscrewing of the adapter (ref. 44) placed on turbine body (fig. 20 ref. 19) or on the rotate flange (fig. 10 ref. 51).

Figure 20 shows the functioning of the equipment to check the metal dowel with internal threaded hole. In figure, it's possible to note some references of figure n°3 with the substitution of the adapter of the dowel at threads rod (fig. 3 ref. 43) with the adapter for internal threaded hole (ref. 44). The proximity switch (ref. 21) placed inside the pull shaft must be disabled on the unit control. The reference n°61 indicates the metal dowel at internal threaded hole.

The operator activates the buttons (fig. 2 ref. 28) over the body of the equipment and it sends a low pressure inside the second circuit to put a low pressure in the chamber of the upper chamber (composed by the ref. 5, 6, 30 of the fig. 3 or 10) of the piston (ref. 30). The pressure must have the power to win the spring force (fig. 3 ref. 14), variable between 0 to 355N, plus the force to catch up the fiictional force to allow the descent of the group of load foot.

The pressure exercises are of two value regulated by mean the electro-valve (fig. 11 annotation "I"), the first value is less high than the second because in the first time by means of the position transducers (fig. 1 ref. 67) is made a lowering of the loading foot (fig. l ref. 24) of 13 mm, to obtain this course the helicoidal spring (fig. 3 ref. 14) is less compression (the length is 46 mm) with a request of 262 N. At this value is added a value of 100 N to win the frictional force. In this case, the pushing area (calculated in previous) is 8399,25mm² and

When is applied the first pressure value to allow at the worker to adjustable the loading foot (fig. 19 ref. 24) leaning on the wall acting on the bolts (fig. 19 ref. 57). When the worker press for the second time the button (ref. 28), there is an elevation of the pressure at the second value of the pressure with a positioning the loading foot in lower position. It must be capable of compress the spring until at the value of 27 mm. At this value is added a value of

300 N to win the frictional force and the area of push is 8399,25 mm² . The value can be:

The foots go down until they are leaned on the wall where is placed the metal dowel to be checked. The foots of the equipment can't actuate the proximity switch diameter 18 mm XS118B3NAL2 (fig. 19 ref. 33) because it is needed to reserve a stroke of 8 mm to make the test of pulling and it's necessary repositioning of the height leaning the foots (fig. 19 ref. 12, 24). In case is detected an increasing of the pressure in the chamber over the piston by means of the pressure transducer (the pressure switch (annotation "Dl") fig. 11), it is due at the load foots in leaned otherwise doesn't allow to put in the circuit the high pressure.

Positioning the foots of loading (fig. 3 or 10 ref. 12, 24), the equipment is ready for the pull test, if hasn't been activate the switch proximity XT1 12S1 PAL2 (fig. 19 ref. 34) collocated at the end of the path the cylinder (fig. 3 and 10 ref. 30). In the equipment, the manual screwing is obtained acting on the lever (fig. 9 and 10 ref. 55) that puts in rotation the toothed wheels (fig. 9 and 10 ref. 53 and 52) and the operator must give a manual consensus to pressurize the second circuit.

The first path upper at the 8 mm of the inferior limit of the course serves for the repeatability of the test because with an identical metal dowel in dimension and in assembly is possible to do again the test without regulating the load foots. Further, during the screwing, if there isn't this lifting, is possible that the foots leaning on the wall, can prevent at the adapter to screw on the dowel.

The procedure continues by giving a consensus of put in pressure the second circuit.

The operator at this time can move away from equipment of test the dowel, he can act on the control unit that it's placed near the equipment. If the equipment is in horizontal position or vertical with head under, is necessary the support of the second worker and must be active a function on unit control. For safety reason, the second worker must act on two buttons everyone with a different hand (fig. 2 ref. 28 and 29 or fig. 9 ref. 18 and 62) that are disabled by unit control by their normal function and the first worker can start the test pull of the dowel. The test consists in keeping in pressure the upper chamber of the cylinder for a determined time.

through testing the different metal dowel normally available in commerce in relation to the diameter of the threads of the screw. However, in the different application the dowel, can be placed for minor values of effort the comparison to the maximum value admissible to the products. Must be expected a function to insert the value of axial solicitation to whom the dowel can be tested. By this value is possible to obtain the working pressure, it's important to verify that the value is always inferior to the maximum value admissible of the screw inserted in the metal dowel.

If the dowel remains in position, the equipment of stress doesn't make any movement and after a pre-established time it removes the high pressure in the circuit. It sends a signal of correct performance of the test.

Instead, in case the dowel doesn't resist at the solicitation, the dowel advances with a reposition of the equipment to 8 mm of distance and the loading foot actives the proximity switch of diameter 12mm XT1 12S1 PAL2 (fig. 19 ref. 34) that signs the failure of the test of resistance of the metal dowel.

The central unit stores the following information on an e-prom and/or can print a report with these items:

Test n°: -> Progressive Number of the test, it's given in automatic way from the central unit. Type of metal dowel: -> It's selected by a manual selector on central unit, in this case is the dowel at rod with internal threaded (fig. 15) but it might a dowel at threaded rod (fig. 12). Metal dowel test: -> diameter of the dowel or the diameter of bolt screwed in the dowel with internal threads (at choose of the user).

Type of control of the screwing: -> In this case it's made the visual inspection by worker (this function serves in case of anomaly or damage at the dowel to have the sequence and types of the operations of the worker).

Value of the solicitation of the test at metal dowel: -> It's given by date storage in the hydraulic unit control or it's obtained by the knowledge of the pressure exerted on the cylinder (fig.3 and 10 ref. 30) during the test.

Result of the test: -> If it isn't being activated the proximity switch of diameter 12 mm (fig. 6, 8, 19 ref. 34) the result of the test is positive, if the proximity switch of diameter 12 mm (fig. 6, 8, 19 ref. 34) is being activated the result is negative because the dowel hasn't resisted at the stress test.

At end of the test it's possible to mark near the dowel with a seal so to guarantee the happened performance.

At the end of the test is taken away the high pressure inside the upper chamber maintaining the minimum value to guarantee the support of the loading foots because otherwise the helicoidally spring (fig. 3 and 10 ref. 14) would lift the loading foots. In this way is possible to reduce the overloaded at flex of the threads of the adaptor (fig. 16). It serves to avoid that the equipment falls down in case that the metal dowel gives away and the equipment isn't supported. When the high-pressure circuit is disabled the buttons (fig. 2 ref. 28 and 29) are activated and the worker can operate with them.

When the equipment is supported by worker it's possible to discharge the pressure from the upper chamber to allow the raising the loading foots by mean of the helicoidally spring (fig. 3 and 10 ref. 14). The operator with the action of the buttons on the body machine can start with the procedure of unscrewing (fig. 19 ref. 29). It's done by entering the pressurised oil in the turbine in the connection that was the connection of discharge during the screwing. While the connection that during the screwing was the entrance of the pressurised oil during the unscrewing is sent in discharge. The unscrewing is made without increasing the pressure if there isn't problem of friction on the threads and it is finished when all threads are unscrewed and the equipment can be extracted. In the equipment, the manual unscrewing is obtained acting on the lever (fig. 9 and 10 ref. 55) that puts in rotation the toothed wheels (fig. 9 and 10 ref. 53 and 52).

Figure 21 shows the equipment with adapter to check the metal dowel at threaded rod (ref. 60) placed with the axe inclined. In figure, it's possible to see the important of to have the loading foots orientable. In particular, it's possible to see that the configuration with spherical join (ref. 22) allows a better alignment if the dowel is inclined on two axes because the attachment of the foot (ref. 24) with iron block (ref.56) to allow to compensate an only one inclination the second inclination it's possible correct it only with the rotation the equipment on the dowel. The application of the extension in reinforce polymer (ref.25) allows to have a better adjustable of the length of the foots.

REFERENCES:

Reference n° 1: Emergency button puts in unloading the two high pressure circuits.

Reference n° 2: Setting the second oil entrance into the upper chamber of the cylinder or for apply the vent valve.

Reference n° 3: Upper closure is bolted on the central shaft (ref. 4) with an OR gasket of kept at the pressure.

Reference n° 4: Central shaft that takes the force for the checking test from the upper closure (ref. 5) and the force is transmitted at the turbine body (ref. 19) on whom is screwed the adaptor (ref. 43 or 44). The central shaft is leaning on the turbine body by means of the fifth wheel (ref. 18).

Reference n° 5: Upper closure of the chamber of the cylinder where is the piston (ref. 30), it is screwed on the external body (ref.6) with an OR gasket of kept at the pressure. The pressure exerts on upper closure is (ref. 5) is used to put in stress the central shaft (ref. 4) to make the traction of the metal dowel (ref. 60 or 61) by means of the adaptor (ref. 43 or 44).

Reference n° 6: External body inside of it slides and it's centred the piston (ref. 30), the kept is assured by the gasket (ref. 7 and 27).

Reference n° 7: External gasket of driving piston (ref. 30) acts on the internal surface of the external body (ref. 6).

Reference n° 8: Internal gasket of driving piston (ref. 30) on the central shaft (ref. 4).

Reference n° 9: Metal plug for locking of the leg group to avoid the rotation of the support (ref. 10).

Reference n° 10: Support of the threaded rod brings loading foot, it's inserted inside in hole done in the piston (ref. 30) and it's kept in position with the metal plug (ref. 9).

Reference n° 11 : Guide in polymer reinforced placed on the end of the shaft of support of the leg (ref. 10) to avoid that the support (ref. 10) is scraped against of the buttonhole of the body cylindrical (ref. 6).

Reference n° 12: Threaded rod to allow the adjustable of the loading foot (ref. 24 and 23) in function of the height of the metal dowel (ref. 60 and 61) on whom is made the test of stress. Reference n° 13: The guide in polymer allows the centring of the spring (ref. 14). It's kept in position on the central shaft (ref.4) with a metal plug.

Reference n° 14: Helicoidally spring (technical data in fig. 4) in round wire to perform the placing in high position of the legs when in the upper chamber of the cylinder there isn't the pressure. Reference n° 15: Metal ring for upper blocking of the bearing (ref. 16).

Reference n° 16: Bearing allows the centring the turbine (ref. 19) on the shaft (ref. 4).

Reference n° 17: Bearing of centring and support of the turbine (ref. 19) at the external body (ref. 40 or 59).

Reference n° 18: Fifth wheel allows the support of the central shaft and the transmission of the tractor force and the rotation of the turbine (ref. 19).

Reference n° 19: Turbine for rotation of the adaptor (ref. 43 or 44). It is centred on the external body (ref. 38) by mean of bearing (ref. 17).

Reference n° 20: Support in tube for bringing of the switch proximity (ref. 21).

Reference n° 21: Switch proximity of type XTl 12S1 PAL2 allows to verify the complete screwing of the metal dowel (ref 60) inside the adapter (ref. 43). It's excepted to allow the unscrewing and the test for checking the dowel with internal hole threaded (ref. 61).

Reference n° 22: Spherical articulation, it brings the pin (ref. 23) bearing the loading foot (ref. 24). The spherical articulation (ref. 22) allows the alignment the axle of the equipment to the axle of dowel to have an axial stress.

Reference n° 23: Pivot load-bearing of the support foot, it's inserted inside the spherical articulation (ref. 22) or of the support of the foot orientable to an only axis (ref. 56).

Reference n° 24: The load-bearing foot is brought by the spherical articulation (ref. 22) or by the block of support (ref. 56) by mean of a pivot (ref. 23).

Reference n° 25: Extension in polymer reinforced with high coefficient of frictional to avoid the slipping of the load-bearing foot to allow to make the test on metal dowel in particular position or with encumbrance. It's blocked at the foot (ref. 24) by mean of screws and metal plug.

Reference n° 26: Entrance oil inside the upper chamber of the cylinder placed on upper closure (ref. 5).

Reference n° 27: Gasket of kept of the piston (ref. 30) on the cylinder body (ref.6) at the pressure exercised inside of the upper chamber composed by the components ref. 5, 6, 30.

Reference n° 28: The button is actuated to make the go up and down at low pressure the piston (ref. 30) activating the hydraulic unit central or when it's disabled by hydraulic unit control, it has the function of safety to avoid accidents at second worker.

Reference n° 29: The button is actuated to make the rotation at low pressure of the turbine (ref. 19) for screwing and unscrewing activating the hydraulic unit central or when it's disabled by hydraulic unit control, it has the function of safety to avoid accidents at second worker. Reference n° 30: The piston has the function to make to go down the legs composed (ref. 10, 11, 12, 22 or 56, 23, 24) to unload the force of stress of the test on the metal dowel.

Reference n° 31 : Gasket of kept of the pressure exerted inside the upper chamber of the piston on the shaft (ref. 4).

Reference n° 32: Gasket for cleaning the central shaft (ref. 4), it serves to assure the removal of the impurity on the central shaft to prevent the usury of the gaskets (ref. 8, 31).

Reference n° 33: Proximity switch type XS1 Ml 8 is placed on the body (ref. 6) and it detects the support of the leg (ref. 10). It serves to check the correct position of the leg before the test of verify.

Reference n° 34: Proximity switch type XT1 M12 is places on the body (ref.6) and it detects, after it has put in pressure the chamber of cylinder, if there is the subsiding of the metal dowel. Reference n° 35: Metal ring is screwed on the other metal ring (ref. 36) and it allows to bring in place the bearing (ref. 17) and it' s centred on the j oining body (ref. 40) that allows the rotation of the turbine (ref. 19).

Reference n° 36: Metal ring brings the bearing (ref. 16) and it's screwed on the metal ring (ref. 35) for kept in position the body turbine (ref. 19).

Reference n° 37: Spacer in composed material of type PCMW 426601.5 allows to lean the turbine group (ref. 17, 19, 35, 36) on the shaft of pull (ref. 4) allowing an axial pull and with reducing of the friction that it can be generated during the rotation of the turbine. The force of compression of the spacer (ref. 37) is made with rotation of the shaft (ref. 4) after is placed the lid (ref. 5) and before place the metal plug for joining the shaft at the lid.

Reference n° 38: Body in metal of union, it's joined the base (ref. 40) where it centres the bearing (ref. 17) at body (ref. 6) in which is placed at its inside the piston (ref. 30).

Reference n° 39: Gasket of creeping of the rotation body, it has the function to keep the exercised pressure on the surfaces of the blading of the turbine (ref. 19).

Reference n° 40: Inferior base to centre the turbine (ref. 19) by mean of the spherical bearing

(ref. 17), it brings the special gaskets for rotation body (ref. 39 and 42).

Reference n° 41: Hydraulic connection for circulation of the oil inside the turbine for making the rotation. By an entrance is made the ingress the pressurised oil and by the other connection is made the unloaded of the oil.

Reference n° 42: Gasket of creeping of the rotation body, it has the function of keeping in pressure of the pressure exercised inside in the turbine (ref. 19).

Reference n° 43 : Adapter for metal dowel with rod threaded showed in figures n° 13, 14. It has the configuration of threaded rod for screwing on body turbine by a side and has the configuration of pivot with threaded hole for screwing on dowel inside of it, there is the hole for a passage of the proximity switch (ref. 21) to check the correct position of the dowel (ref. 60). On the external surface, there's a machining at hexagon socket key.

Reference n° 44: Adapter for metal dowel with internal threaded hole showed in figure n° 16, 17. It has the configured extremity with a threaded rod for the screwing in the dowel (ref. 61) to make the test. With this adapter, the proximity switch (ref. 21) is disabled. On the external surface, there's a machining at hexagon socket key.

Reference n° 45: Plate to prevent the unscrewing of the adapter of the dowel (ref. 43 or 44), it is fixed with one screw on the turbine body (ref. 19) or on the rotation flange (ref. 51) bring the wheel toothed (ref. 52) and two screws are placed of reaction against the hexagon of the adapter (ref. 43 or 44).

Reference n° 46: Screws for fixing the plate (ref. 45) to prevent the unscrewing of the adapter (ref. 43 or 44).

Reference n° 47: Seeger to stop the pin (ref. 23) brings the load-bearing foot (ref. 24).

Reference n° 48: The screws for anchoring of the elongation in polymer (ref. 25) at the load- bearing foot (ref. 24).

Reference n° 49: Metal plug for centring the elongation in polymer (ref. 25) on the bearing foot (ref. 24).

Reference n° 50: Bolts to prevent the unscrewing of the spherical articulation (ref. 22) or of the support (ref. 56) to allow the orientation along an only axle.

Reference n° 51 : Rotation flange of support of the toothed wheel (ref. 52) for manual screwing, it brings two types of adapters (ref. 43 or 44) for metal dowel at threads rod (ref. 60) and dowel a rod with internal threaded hole (ref. 61).

Reference n° 52: Wheel toothed to perform the manual screwing of the adapter on the dowel (ref. 43 or 44), it's fixed at the rotation flange (ref. 51).

Reference n° 53: Pinion of transmission of the rotation force from the lever (ref. 55) at the toothed wheel (ref. 52).

Reference n° 54: Support of the lever to make the manual screwing complete of bearings, it brings of the switch (ref. 62).

Reference n° 55 : Lever to make the manual screwing, it's supported with bearings in the support (ref. 54) and at his extremity is placed a pinion (ref. 53).

Reference n° 56: Block in iron brings the support of the load-bearing foot (ref. 24) to allow the orientation along an only axle. Reference n° 57: Bolts for adjustable in height of the loading foot (ref. 24) to allow the scrolling the threaded rod (ref. 12) in the support (ref. 10).

Reference n° 58: Bushing to allow the rotation of the load-bearing foot (ref. 24) is placed by mean of pin (ref. 23) in the iron block of support the foot (ref. 56).

Reference n° 59: External ring in iron to bring the bearing (ref. 17), it's screwed on the body in metal of joining (ref. 38).

Reference n° 60: Metal dowel at threaded rod (fig. 12) on which is made the test of stress. Reference n° 61 : Metal dowel at rod with internal threaded hole (fig. 15) on which is made the test of stress.

Reference n° 62: Button placed on the support (ref. 54) to check the present one hand worker during the pulling test in the equipment with manual screwing/unscrewing.

Reference n° 63: Group of protections of the movement of the leg to avoid contacts with the hand of the worker. The length of every protection is different for every side of the support of the threaded rod (ref. 12) bringing the loading foot to allow the operation on the bolts (ref. 57) to adjustable the position of threaded rod.

Reference n° 64: Protection placed on the support (ref. 10) of the threaded rod (ref.12) to avoid pinching of fingers between the guide in polymer (ref. 11) or the support of the threaded rod (ref. 10) and the external body (ref. 6).

Reference n° 65: Metal plug of join the metal rings (ref. 35 and 36).

Reference n° 66: Protection placed on the support of the threaded rod equal function of ref. 64, it has an extension of the iron sheet for bringing the shaft of the device (ref.67) for checking the course of the piston (ref. 30).

Reference n° 67: Position transducers, it's a linear displacement transmitters based on potentiometric technology.

Reference n° 68: Support of the position transducers.

Reference n° 70: Possible obstacle is positioned near or sustained by the metal dowel.

Claims

CLAIMS.

1 ) Equipment for extracting metal dowels, adapted to exert an extraction force which is variable according to the installed dowel, this force verifying of resistance to traction of a dowel at stress values computed for an installation within the maximum allowable stress for the dowel, said equipment consist:

♦ A central body (Fig. 1; 6 - Fig. 3; 6);

♦ A turbine assembly (Fig. 3; 40 - Fig. 3; 19 - rotary body Fig. 10; 51) which is used for screwing said equipment on/in a metal dowel (Fig. 1; 60 - Fig: 3; 60 - Fig. 20; 61);

♦ An adapter (Fig. 1; 43 - Fig. 3; 43 - Fig. 10; 43 - Fig. 20; 44) which is screwed on the turbine (Fig. 3; 19) or rotary body (Fig. 10; 51) that they create an assembly composing with central shaft (Fig. 3; 4 and Fig. 10; 4);

♦ Four extensions (Fig. 1; 10 - Fig. 3; 10 - Fig. 10; 10) which, placed in the holes of the piston, are completed with four legs (Fig. 1; 12 - Fig. 3; 12 - Fig. 10; 12), exert an abutment for the pulling force through their bearing feet (Fig. 1; 24 - Fig. 3; 24 - Fig. 10; 25 - Fig. 20; 24), which exert a pulling force, completed with ball joint (Fig. 5; 22 - Fig. 3; 22 ) or the block in iron (Fig. 6; 56 or fig. 10; 56) to allow aligning the equipment to the operating axis of the metal dowel (Fig. 1; 60 - Fig. 3; 60 - Fig. 10; 60 - Fig. 20; 61);

♦ Two connections (Fig. 2; 2, 26 - Fig. 10; 2, 26) of an oil- dynamic circuit, which are used to pressurize an upper chamber of the piston to perform positioning and pull test;

♦ Connections (Fig. 1; 41 - Fig. 2; 41) of low pressure oil-dynamic pipes, which are used to perform an oil recirculation inside the turbine (Fig. 3; 19) which performs a screwing on the metal dowel (Fig. 1; 60 - Fig. 3; 60 - Fig. 20; 61);

♦ A position transducers (Fig. 1; 67 - Fig. 3; 67 - Fig. 9; 67) to check the position of the cylinder. It has the function to allow the first lowering to adjustable of the position of the loading foot and control the position of the leg (Fig. 3; 10 - Fig. 10; 10 - Fig. 20; 10) before the test with comparison between the micro switch XS1 M18 (Fig. 6; 33 - Fig. 10; 33) and the result of the pulling test with the comparison with the micro switch XTl M12 (Fig. 3; 34 - Fig. 6; 34).

♦ A micro-switch XTl M12 (Fig. 3; 34 - Fig. 6; 34) which detects when the legs have reached their limit path in case, during the test, the metal dowel (Fig. 1; 60 - Fig.3; 60 - Fig. 10; 60 - Fig. 20; 61) does not resist to the stressing force, this micro-switch (Fig. 3; 34 - Fig. 6; 34) detects whether, after having pressurized the cylinder chamber, with the following pull of it, what it been the result on the dowel (Fig. 1; 60 - Fig. 3; 60 - Fig. 10; 60 - Fig. 20; 61) with comparison of the position transducer (Fig. 1; 67 - Fig. 3; 67 - Fig. 9; 67 - Fig. 19; 67) .

♦ A micro-switch XSl M18 (Fig. 6; 33 - Fig. 9; 33 - Fig. 19; 33), which detects when the lowest position of the legs has been reached, and, if said micro-switch (Fig. 6; 33 - Fig. 9; 33 - Fig. 19; 33) is activated before the test, said legs (Fig. 3; 10) must be re-positioned, inserting a polymer reinforced extension (Fig. 1; 25) or lowering a threaded bar (Fig. 1; 12) which composes the legs (Fig. 3; 12 - Fig. 10; 12 - Fig.20; 12), said micro-switch (Fig. 6; 33 - Fig. 9; 33 - Fig. 19; 33) being used to verify that the legs are in a correct position before the check test, and whether the leg fastening drops to a value lower than 8mm, which is the field of reading of the micro-switch (Fig. 6; 33 - Fig. 9; 33 - Fig. 19; 33 ), it is activated and signals the need of adjusting the bearing feet height; and with comparison of the position transducer (Fig. 1; 67 - Fig.3; 67 - Fig. 9; 67 - Fig. 19; 67) .

♦ Adaptor metal dowels (Fig. 1; 43 - Fig. 3; 43 - Fig. 10; 43 - Fig. 20; 44) adapted to assume several configurations depending on the dowel (Fig. 1; 60 - Fig. 3; 60 - Fig. 20; 61) on which the test must be performed.

2 ) Equipment according to claim 1, it is composed of:

♦ A rotation-preventing device (Fig. 6; 45 - Fig. 6; 46) applied on the turbine body (Fig. 3; 19 - Fig. 6; 19 - rotary body Fig. 9; 51), which is used to prevent the adapter (Fig. 3; 43 - Fig. 9; 43 - Fig. 20; 44) from being unscrewed:

♦ A central shaft (Fig. 3; 4 - Fig. 10; 4 - Fig. 20; 4) which is used to take the force for the pull test from an upper closure (Fig. 3; 5 - Fig. 10; 5) and transmit it to the turbine body (Fig. 3; 19 - Fig. 20; 19, or on the rotary body Fig. 10, 51) on which an adapter (Fig. 3; 43 - Fig. 10; 43 - Fig. 20; 44) is screwed, the shaft (Fig. 3; 4 - Fig. 10; 4 - Fig. 20; 4) placed onto the turbine body (Fig. 3; 19 - Fig. 10; 51 - Fig. 20; 19) through a fifth wheel (Fig. 3; 18 - Fig. 10; 18 - Fig. 20; 18);

♦ The upper closure (Fig. 3; 5 - Fig. 10; 5) of the cylinder chamber where the piston (Fig. 3; 30 - Fig.10; 30), is after having placed the legs (Fig. 3; 10), composed of positions (Fig. 3; 10, 12, 22 or 56, 24, 25, 50, 57 - Fig. 10; 10, 12, 22 or 56, 24, 25, 50, 57 - Fig. 20; 10, 12, 22 or 56, 24,) against the abutment wall, exerts a pressure on the surface of a cover (Fig. 3; 5 - Fig.10; 5), which, being screwed on the central shaft (Fig. 3; 4 - Fig. 10; 4) through the adapter (Fig. 3; 43 - Fig. 10; 43 - Fig. 20; 44 - Fig. 13 - Fig. 16), performs the stress pull for the metal dowel (Fig. 3; 60 - Fig. 10; 60 - Fig. 20; 61); ♦ An external body (Fig. 3; 6 - Fig. 10; 6) on which the piston (Fig. 3; 30 - Fig. 10; 30) performs cantering and sliding;

♦ A metal plug (Fig. 3; 9 - Fig. 10; 9) to lock the rotation of a leg attachment (Fig. 3; 10 - Fig.10; 10);

♦ The leg attachment (Fig. 3; 10 - Fig.10; 10) to the piston (Fig. 3; 30 - Fig. 10; 30), said legs being inserted inside a cylindrical seat of the piston (Fig. 3; 30 - Fig. 10; 30) and kept in position by the metal plug (Fig. 3; 9 - Fig. 10; 9);

♦ A threaded bar (Fig. 3; 12 - Fig. 10; 12) which allows adjusting the bearing feet (Fig. 3; 24, 25 - Fig. 10; 24, 25) depending on the height at which the pull test for the metal dowel (Fig. 1; 60 - Fig. 3; 60 - Fig. 20; 61) must be performed;

♦ A polymer guide (Fig. 3; 13 - Fig. 10; 13), which is used to centre a spring (Fig. 3; 14 - Fig. 10; 14), said guide (Fig. 3; 13 - Fig. 10; 13) being kept in position by the metal plug placed on the central shaft (Fig. 3;4 - Fig. 10;4);

♦ The spring (Fig. 3; 14 - Fig. 10; 14), preferably made of a round wire, which is used for repositioning the legs in high position, when there is no pressure inside the upper chamber;

♦ A bearing (Fig. 3; 16 - Fig. 10; 16), which is used to centre the rotation of the central shaft (Fig. 3; 4 - Fig. 10; 4 - Fig. 20; 4) to the external turbine body (Fig. 3; 19 - Fig. 20; 19 or on the rotary body, Fig. 10; 51);

♦ A bearing (Fig. 3; 17 - Fig. 10; 17 - Fig. 20; 17) to centre and supporting the rotation of the turbine (Fig. 3; 19 - Fig. 20; 19 or on the rotary body, Fig. 10; 51);

♦ A fifth wheel (Fig. 3; 18 - Fig. 10; 18), which is used as an abutment for the rotation of the central shaft (Fig. 3;4 - Fig. 10;4 - Fig. 20;4) and for the transmission of the pulling force; and

♦ The turbine (Fig. 3; 19 - Fig. 20; 19 or on the rotary body, Fig. 10; 51) to rotate the adapter (Fig. 3; 43 - Fig. 10; 43 - Fig. 20; 44).

3 ) Equipment according to claim 1, it's composed of: - a micro-switch XS1 M12 (Fig. 3; 21 - Fig. 10; 21), which is used to verify the complete screwing of the metal dowel (Fig. 12 - Fig. 1; 60 - Fig. 3; 60 - Fig. 10; 60) inside the adapter (Fig. 3; 43 - Fig. 10, 43 - Fig.13) and is excluded for unscrewing and for the test on dowels (Fig. 15 - Fig. 20; 61) with threaded bush adapter (Fig. 16);

♦ A ball joint (Fig. 3; 22 - Fig. 10; 22 - Fig. 20; 22) completed with pin for fastening inside a bearing foot (Fig. 3; 24 - Fig. 10; 24 - Fig. 20; 24), said ball joint (Fig. 3; 22 - Fig. 10; 22 - Fig. 20; 22) allows to align the equipment to the axis of the central dowel, performing a completely axial pull;

♦ In alternative, the bearing foot (Fig. 3; 24 - Fig. 10; 24 - Fig. 20; 24) blocked onto the iron block (Fig. 3;56 - Fig. 10;56 -Fig. 20;56) through a pin (Fig. 6; 23 - Fig. 7; 23);

♦ A polymer reinforced extension (Fig. 3; 25 - Fig. 10; 25) of the bearing foot, which allows performing the metal dowel test (Fig. 1; 60 - Fig. 3; 60 - Fig. 10; 60) also in particular positions or with encumbrances (Fig. 3; 70; Fig. 10; 70)

♦ An oil inlet (Fig. 3; 26 - Fig. 10; 26) from inside the upper cylinder chamber;

♦ A piston (Fig. 3; 30 - Fig. 10; 30) adapted to descend the legs (Fig. 3; 10, 12, 22 or 56, 24, 25, 50, 57 - Fig. 10; 10, 12, 22 or 56, 24, 25, 50, 57 - Fig. 20; 12, 22 or 56, 24);

♦ The oil-dynamic connections (Fig. 2; 41 - Fig. 20; 41) for oil circulation inside the turbine body, wherein, to perform a rotation from an inlet, pressurized oil is entered, while on the other connection it is immediately discharged; in this way, the rotational speed is proportional to the oil flow speed, and consequently to flow-rate.

4 ) Equipment according to claim 1, characterized in that it further comprises:

♦ A first emergency push-button (Fig. 1; 1 - Fig. 3; 1 - Fig. 10; 1) which, if actuated, immediately discharges the whole circuit;

♦ Push-buttons (Fig. 2; 28 - Fig. 10; 28) for lifting and lowering the legs (Fig. 1; 10) for the pull test after screwing the equipment with the adapter (Fig. 3; 43 - Fig. 20; 44 - Fig. 13 - Fig. 16) on the metal dowel (Fig. 1; 60 - Fig. 3; 60 - Fig. 20; 61 - Fig. 12 - Fig.15); and

♦ A second push-button (Fig. 1; 29 Fig. 2; 29) for screwing/unscrewing the adapter (Fig. 1; 43 - Fig. 3; 43 - Fig. 10, 43) on the dowel (Fig. 1; 60 - Fig. 3; 60 - Fig. 20; 61), said second push-button (Fig. 1; 29) can optionally be replaced by a manual screwing system (Fig. 9), where a lever (Fig. 9; 55), placed through bearings on a support (Fig. 9; 54), engages through the pinion (Fig. 9; 53) which rotates the toothed wheel (Fig. 9; 52) fastened on the rotary body (Fig. 10; 51) on which the adapter is screwed (Fig. 3; 43 - Fig. 10; 43 or Fig. 20; 44).

♦ For safety, when the circuit at high pressure is activated the push-buttons (Fig. 2;28 Fig. 2; 29) are disabled of their function and they are used, if it's present a second worker to keep the equipment, to detect the position of the hand to avoid he has put them in dangerous positions. In the equipment at manual screwing it's placed on the support (Fig. 9; 54) the push-button (Fig. 9; 62), it is used to detect the hands of the second worker to avoid he has the hands in dangerous position because it isn't installed the button (Fig. 1; 29).