Fluid Operated Tool

Technical Field

The present invention relates to fluid-operated tools for tightening and loosening threaded connectors, includi an inner threaded part such as for example a stud and an outer threaded part such as for example a nut screwed on the stud.

Background Art Fluid-operated tools of the above mentioned general type are known in the art. In particular, tools are know in which one element pulls the stud so as to elongate it, and another element of the tool thereafter turns the nut as to retain the achieved elongation. Therefore, the mechanisms for coordination of the application of the pulling force to the stud and of the turning force to the nut are quite complicated. It has also been found that a substantial power of the fluid drive is consumed in order to achieve a desired elongation of the stud. It is believed to be clear that it would be advisable to design tool which has a lower power consumption.

Disclosure of the Invention

Accordingly, it is an object of the present invention to provide a fluid operated tool for tightening and loosening threaded connectors, which avoids the dis¬ advantages of the prior art.

More particularly it is also an object of the present invention to provide a fluid operated tool for tightening and loosening threaded connectors in which the respective coordination of the elongation of the stud and turning of the nut is performed in a simple manner.

It is also an object of the present invention to provide a fluid operated tool for tightening and loosenin of threaded connectors which provides a desired elongatio of a stud with a lower power consumption than existing tools.

In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a fluid operated tool for for elongating a stud which has an axis and an end extending out over the nut, the tool has stud pulling means adapted to engage the end of the stud so as to pull the stud, nut turning means adapted to engage the nut so as to turn the nut, first fluid-operated means acting on the stud pulling means so that the stud pulling means pull the end of the stud to elongate the stud, seco fluid-operated means acting on the nut turning means so that the nut turning means turns the nut, the first fluid operated means and the second fluid-operated means communicating with a fluid source so that a pressure flui supplied by the fluid source to the first fluid-operated means and the second fluid-operated means elongates the stud and turns the nut.

When the tool is designed in accordance with the present invention, the coordination between the elongatio of the stud and the turning of the nut is obtained in a simple manner. The fluid pressure of the fluid source ca be applied to the stud pulling means and to the nut turni means simultaneously so as to simultaneously turn the nut and elongate the stud. On the other hand the fluid pressure can be retained by controlling means so that the stud pulling means does not elongate the stud while the n turning means turn the nut.

In accordance with another feature of the present invention, the stud pulling means includes an engaging element arranged to engage the end of the stud and having an axis, the first fluid-operated means being formed as

fluid-operated cylinder-piston means including a pluralit of cylinders arranged on top of one another along the axi and having cylinder chambers, and a plurality of pistons axially movable in the cylinder chambers. When the tool is designed in accordance with these features, the pistons simultaneously apply a pulling forc to the same engaging element which pulls the stud, and a higher pulling force is generated with a predetermined power consumption from the fluid source. Vice versa, the same force which is applied for pulling the stud is produced with a lower power consumption of the fluid source.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantage thereof, will be best understood from the following description of specific embodiments when read in connecti with the accompanying drawings.

Brief Description of the Drawings

FIG. 1 is a view showing a section of a fluid-operate tool for elongating a stud and turning a nut, in accordan with the present invention; FIG. 2 is a plan view, partially sectioned, of the fluid operated tool in accordance with the present invention;

FIG. 3 is a view showing a further embodiment of a drive for the inventive fluid-operated tool; FIG. 4 is a view illustrating indicating means of the inventive fluid-operated tool, in accordance with the invention;

FIG. 5 is a view of a further embodiment of the inventive fluid-operated tool;

FIG. 6 substantially corresponds to the view of FIG. but showing a support element for the multi-tool arrangement of FIG. 6, only without the tools.

Best Mode for Carrying Out the Invention The fluid operated tool in accordance with the presen invention is used for tightening and loosening a threaded connector which, for example, includes a stud identified with reference numeral 1 and a nut which is screwed on th stud and identified with reference numeral 2. A first engaging element 3 engages the stud 1 via interengaging threads 4 and is displaceable in an axial direction of th threaded connector so as to pull the stud and elongate th latter. A second engaging element 5 is engageable with t nut 2 via interengaging hexagonal opening in the element and hexagonal outer surface of the nut 2 and is turnable about the axis of the threaded connector so as to turn th nut.

Means is provided for displacing the first engaging element 3 in the axial direction of the threaded connecto This means includes a plurality of cylinders 7 which form working chambers and a plurality of pistons 8 each dis¬ placeable in a respective one of said working chambers. passage 9 communicates with a fluid source and has a plurality of outlet openings, each opening into a respective one of the working chambers. The pistons 8 ab against one another and the upper piston 8 abuts against cap 10 which is connected with the engaging element 3 through interengaging threads 11. When a lower portion o the engaging element 3 is screwed on the stud 4 and a working fluid is supplied from the fluid source into the chambers 7, the pistons are displaced in the chambers in abutment against one another and displace the engaging element 3 upwardly in the drawings so as to pull the uppe end of the stud 1 upwardly and therefore to elongate the stud. Due to the provision of the plurality of pistons,

with the same power of the fluid source a pulling force developed by the pistons and applied to the engaging element 3 is significantly higher than when a single membe with a single piston is provided. As can be seen from the drawings, the pistons 8 are circular and surround the engaging element 3. Since they have radially inner portions abutting against one another which can be formed as portions extending in the axial direction as shown in the drawings, the area between the pistons 8 and the engaging element 3 is sufficiently sealed, and no additional sealing means is needed to prevent penetration of the fluid into this area. The cylinders 7 also abut against one another, for example by their radially outer projections which extend in an axial direction. Therefore, no sealing means is needed in the radially outer region to prevent leaks of the fluid. The pistons and the cylinders are formed as easily mountable and demountable blocks, so that the cylinder-piston arrangement is formed as a modular arrangement. Dependin on the desired stud elongation, the availability of space and fluid pressure, more or less cylinder-piston blocks a working chambers can be provided to obtain the desired st elongation in a particular tool. Also, as shown in broke lines in FIG. 1, the engaging element 3 can be composed o two axial portions which are connectable with one another for example by threads.

Means for turning the nut 2 includes two drive plates 12, a ratchet 13 located between the drive plates and engaging with the engaging element 5 through a plurality splines 14, and a pawl 15 with two engaging formations 16 and 17 engageable in the teeth of the ratchet 13. The pa 15 is turnably mounted on the plates 12, for example, by pin 18. The means for turning the nut further include a working chamber 19 and two pistons 20 displaceable in the working chamber 19 in opposite directions. When the working fluid is supplied in the upper part of the chambe

19 it displaces the upper piston 20 downwardly in FIG. 2 and the piston turns the drive plates in one direction. the fluid is supplied to the lower portion of the working chamber 19 the lower piston 20 is displaced upwardly in FIG. 2 and turns the drive plates in the opposite direction. When the driving plates 12 are turned, the pa 15 is also turned, a respective formation 16 or 17 of the pawl 15 engages in the teeth of the ratchet 13 and turns in the respective direction, and as a result the engaging element 5 is turned and turns the nut 2. Depending on whether a tightening or a loosening of the nut is require the direction of turning of the drive plates 12 and there of the engaging element 5 is selected. In order to switc the directions of turning, a switching element is provide It includes a spring biased pin 21 arranged in a handle 2 which accommodates a spring 22'. In order to switch the direction of turning, an operator turns the handle 22 in clockwise or counterclockwise direction so that the pin 2 engages in a small recess of the pawl 15 at one side of t axis 18 or engages another small recess of the pawl 15 at the opposite side of the axis 18. Depending on these engagements, either the engaging formation 16 or the engaging formation 17 engage in the teeth of the ratchet 13. Upon supplying the fluid to the respective upper or lower piston 20, the drive plates 12 and thereby the ratchet 13 can be turned in one direction or in another opposite direction, so as to turn the engaging element 5 a respective direction and as a result to turn the nut 2 the respective direction. The pawl 15, in addition to the above mentioned small recesses on the opposite sides of the axis 18 also has a central recess or a so-called neutral recess in which the pin 21 can engage as well.

The tool is further provided with a valve which is identified as a whole with reference numeral 23. The val 23 actuated by an operator can establish communication

through the chamber 19 to the passage 9, or interrupt suc communication.

The fluid operated tool in accordance with the presen invention operates in the following manner: First the handle 22 is turned to a neutral position, in other words a position in which the pin 21 engages in the central recess on the rear side of the pawl 15. Then fluid is supplied for example in the upper part of the chamber 19, flows through the chamber 19 and then flows into the passage 9 when the valve 23 is open. From the passage 9 the fluid flows into the chambers 7, displaces the pistons 8 upwardly and thereby displaces the engaging element 3 with the member 10 also upwardly. As a result, the upper part of the portion of the stud 1 is pulled upwardly and the stud 1 is elongated. Then, if it is necessary to tighten the threaded connector, the switchin pin 22 is turned so that the pin 21 engages in the respective recess of the pawl 15, the valve 23 is closed, and the fluid supplied into the chamber 19 turns the plat 12 together with the pawl 15, so that the pawl 15 turns t ratchet 13, and through the latter also turns the engagin element 5. As a result, the nut 2 is turned and tightene It is to be understood that for loosening the nut, the switching pin 22 is turned in the opposite direction to engage the other small recess from the rear side of the pawl 15, so that the pawl 15 engages with another engagin formation in the ratchet 13. During turning of the plat 12 the ratchet 13 is turned in an opposite direction to thereby turn the engaging element 5 in an opposite direction, so as to loosen the nut 2.

It is to be understood that the operations for elongating the stud are performed when the valve 23 is open. When however the valve 23 is closed, fluid is not supplied into the passage 9 and into the chambers of the cylinder-piston unit for the stud elongation, but it applies the pressure only in the cylinder-piston unit for

turning the nut. Thus, the stud elongation is retained while the nut is turned.

As can be seen from the drawings, the cylinder-piston unit cooperating with the engaging element 3 and elongati the stud and the cylinder-piston units cooperating with t engaging element 5 for turning the nut are arranged perpendicular to one another. Instead of the cylinder- piston unit for turning the nut shown in the drawings, it is also possible to use a hydraulic motor 24 shown in FIG 3. In this case the output shaft of the hydraulic motor is connected with a worm rack 25 which engages with a wor gear 26. The worm gear is in turn engaged with the engaging element 5 for turning the nut 2. When the hydraulic motor 24 is actuated, the worm rack 25 reciprocates and turns the worm gear 26 with ratcheting s as to turn the nut.

The degree of turning of the nut 12 can be indicated an indicating mechanism which includes a dial gear 24 engaging with the gear 28 which is connected with the engaging element 5 and turnable together with the latter, and a dial pointer 29 associated with the dial gear. The dial gear 27 is provided with a scale, so that during turning of the dial gear 27 resulting from the turning of the engaging element 5 and the nut 2, the dial pointer 29 points to a respective graduation of the scale, to indica the degree of turning of the nut.

The degree of elongation of the stud can be determine in several ways. As shown in FIG. 4, a standard indicato 30 can be arranged on a housing 31 of the tool and provi with a feeler 32 which abuts against an upper surface of the cap 10. Since the cap 10 is connected with the engaging element 3 which in turn engages the end of the stud, the elongation of the stud is measured by the indicator 30 through the displacement of the engaging element 3 during the elongation process.

As can be seen in the central area of FIG. 4 with a cutout, a scale 32' can be provided so that the operator can read the elongation of the stud on the scale. It is also possible to form the engaging element 3 hollow, as shown in FIG. 1 and then to provide an outer sensor which senses the displacement of the elongated element 3 throug the central hole.

In accordance with an advantageous embodiment of the invention, fluid-operated tool can be provided with a plurality of stud elongating means and nut turning means, or in other words with a plurality of units each having t above described stud elongating means and nut turning means. The units are identified in FIG. 6 with reference numeral 33. They are mounted on a circular support 34 an spaced from one another preferably by identical distances. Conduit means 35 connect all units 3 to a fluid source. The tools shown in FIG. 6 can be simultaneously applied o all studs/nuts which are provided on a flange and are to elongated and tightened. Thus, simultaneously it is possible to elongate all the studs and tighten all the nu on such a flange, and the like, by supplying fluid from t fluid source to all units 33.

As can be seen from FIG. 7 in which the tools are removed from the ring 34 the fluid can be supplied throug one of the tools and then distributed over the ring 34 through passages 36 which are drilled in the ring.

When the tool is designed in accordance with the present invention, it provides for many advantages.

By turning the nut down with hydraulic means, there i no stud relaxation once the lifting pressure is taken off the tool. This eliminates the need to tension the stud over and above the required load make up for the relaxation.

The staggering modular system of the drive permits th use of regular industrial hydraulic pressure which in tur assures that there are no seal failures.

The overall radius of the tool can be kept to a minim which permits on most applications to tension all studs simultaneously instead of every second one, or every seco one on one side of the flange and every other one on the other side of the flange.

Turning the nut with hydraulic means gives the operat more torque which also permits loosening of a corroded nu after the stud is pulled up by the tensioner and the nut unloaded. Turning the nut with hydraulic means also allows the operator to tighten the nut prior to tensioning the stud as to pull the flange together, then elongate the stud an keep the elongation on while turning the nut again down onto the flange. Turning the nut with hydraulic means also eliminates faying and surface embedment of the nut onto the flange, since the nut can be turned down onto the flange so that there is no gap between the nut face and the flange face and so that the engaged bolt and nut threads are loaded u before the pulling force is taken off the tensioner.

As the tensioner sits with its housing on the flange surface, measuring by means of dial-indicators is relatively easy since the housing height relates to the flange and the difference between the engaging element height before and after tensioning shows the accomplished elongation.

Finally, another advantage is that the cylinder chambers can be staggered on top of one another without having to seal the area where they meet. Thus, the portions can be added without worrying about leakage. Sure, in this case the engagement means have to be lengthened but that is a minor expense considering that another piece can just be screwed on the top where the puller nut is screwed on since the pistons do not have to be sealed with the engaging element either.

While the invention has been illustrated and describe as embodied in a fluid operated tool, it is not intended be limited to the details shown, since various modifi¬ cations and structural changes may be made without departing in any way from the spirit of the present invention.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.