DESCRIPTION The present invention refers to a portable operating device for loosening and tightening threaded connecting means such as screws, nuts and the like. The invention has been developed with particular regard, but not limitatively, to the hexagonal head screws or nuts used for fixing the wheels of motor vehicles to the respective axles or for fixing the pipe flanges of pipelines, for example oil pipelines or methane pipelines.

An aim of the present invention is to provide a device of the type mentioned above which can easily be transported and operated even without the aid of external power sources (electric, pneumatic, hydraulic power, etc.). Another aim of the invention is that of facilitating the loosening of threaded means which are jammed, for example because of debris, dirt, rust, paint and the like. A further aim of the invention is that of providing a device which is simple and economical to produce, has a high reliability over time, has a low weight and overall size, and which does not require any particular maintenance.

In order to achieve the aims mentioned above, the subject of the invention is a portable operating device of the type indicated in the preamble of the description, characterized in that it comprises a support structure to which are connected at least two arms, of which a first arm is a support arm and a second rotating arm is operatively connected to control means,

actuating means being mounted on the support structure to drive in rotation the control means, bracing means being mounted on the support arm in order to brace the operating device, in use, wrench means being mounted on the operating arm to engage a threaded connecting means, the wrench means being controlled selectively in rotation on actuation of the actuating means in order to loosen and/or tighten the threaded connecting means.

An advantage of the invention is that no bearing point on the ground is required for its use, with the result that it can easily be used even where there is muddy, slippery, sandy and generally yielding or crumbly terrain. In the particular case where the invention is used for operating the screws for clamping a wheel of a vehicle to the respective axle, it is possible to arrange the device in such a way that it bears on one of the screws and levers on the latter in order to loosen another screw. This characteristic is of particular advantage in as far as it makes it possible to loosen or tighten the clamping screws even with the wheel raised, without it being necessary to block it to prevent the possibility of rotation.

In one preferred embodiment, the portable operating device of the present invention comprises a hydraulic jack mounted on a platform pivotally hinged on the support structure. The adoption of the hydraulic jack allows a user to apply without any effort a predetermined torque to the screw to be tightened or loosened, without any risk of applying excessive torque which might damage the threads of the screw.

Further characteristics and advantages will be revealed by the description which follows of a preferred embodiment, with reference to the appended drawings, provided purely by way of

non-limiting example, wherein: Figure 1 is a perspective view of a portable device according to the present invention, Figure 2 is a diagrammatic, partially sectional view of a detail of the device in Figure 1, Figures 3, 4 and 5 are diagrammatic front views of some variants of the operating device in Figure 1, and Figures 6 and 7 are perspective views of a further variant of the operating device, shown in the loosening and tightening configurations, respectively.

Referring now to Figure 1, a portable operating device 10 can be used for loosening or tightening the screws 11 which connect a wheel R to a corresponding axle of a vehicle, for example a motor-lorry. In particular, in Figure 1 the device 10 is illustrated in the position suitable for tightening the screw lla. The device comprises a support bar 12 from which extends a cylindrical idle arm 13 and a cylindrical operating arm 14. On the ends of the arms 13, 14 are mounted, preferably fitted in, two wrenches 15, 16 for hexagonal nuts which can be substituted also by other tightening means of generally known type, such as screw-drivers or wrenches for hexagon socket screws. The two cylindrical arms 13, 14 each preferably consist of an inner cylindrical core 17 (visible in detail in Figure 2) fixed, for example by welding, to the support bar 12. Onto the cylindrical cores 17 of the arms 13, 14 are slipped two respective tubular sleeves 18a, 18b movable in rotation with respect to the cores 17. The sleeves 18a, 18b are locked axially on the cores 17 by known means, for example pins 19, the ends of which engage in peripheral grooves 20 provided on each of the cylindrical cores

17 (see Figure 2).

On the operating arm 14, between the tubular sleeve 18b and the wrench 16 there is inserted a ratchet gear 21 of known type which allows the free rotation of the wrench 16 with respect to the sleeve 18b in only one of the two directions of rotation. The ratchet 21 has two symmetrical ends, each of which comprises an inner shaft 21a with a shaped through bore 21b (square, hexagonal, etc.) to receive, fitted in, a shank 16a of the wrench 16. Concentrically with the inner shaft 21a, each end of the ratchet 21 comprises an outer shaft 21c the outer sleeve of which is shaped, and has, for example, a square or hexagonal cross section, for mounting, fitted in, on the inside of the corresponding shaped end of the sleeve 18b of the operating arm 14. It is therefore possible to reverse the direction of engagement of the ratchet 21 on the operating arm 14 so as to allow the free rotation of the wrench 16 with respect to the sleeve 18b alternately in one or the other direction of rotation.

In proximity to the support bar 12, there is fixed to the sleeve 18b of the operating arm 14 an operating lever 22 onto the end of which there is hinged a preferably cup-shaped body or linkage 23 capable of receiving a push rod 24 of a hydraulic jack 25 of generally known type with manual control 26. The hydraulic jack 25 is mounted on a platform 27 hinged on the support bar 28 and oscillating round an axis parallel to the axes of the arms 13, 14. The jack 25 is provided with a discharge valve 29 and with a selectively insertable load limiter (not illustrated).

The operating lever 22, the cup-shaped body 23 and the platform 27 are able to be tilted about their own articulation axes in the direction of the arrows U1, U2 and U3 in Figure 1 in such a manner that the operating device 10 can assume a mirror-image configuration to that illustrated, suitable for the use of the device for loosening the threaded means lla.

Naturally, in such a case provision should also be made for reversing the direction in which the ratchet 21 is fitted in.

When using the operating device 10, the wrenches 15 and 16 of the cylindrical arms 13 and 14, spaced from each other by a predetermined distance, are placed on two hexagonal nuts or screw heads 11, lla spaced from each other by the same distance equal to that between the axes of the arms 13, 14. The idle arm 13 has the function of support for the whole device 10 which, in order to tighten the screw Ila, is arranged as illustrated in Figure 1. By means of the manual actuator 26 of the hydraulic jack 25 there is brought about an extension of the rod 24 and the consequent rotation in a clockwise direction of the lever 22 which entrains in integral rotation the sleeve 18b, the ratchet 21 and the wrench 16, tightening the screw lla. Once the maximum extension of the rod 24 has been reached, the discharge valve 29 of the hydraulic jack opens and the lever 22 is brought back manually into the initial position, rotating it in an anticlockwise direction and causing the rod 24 to move back into the body of the jack 25. Such rotation of the lever 22 entrains with it the sleeve 18b, but does not cause any rotation of the wrench 16 owing to the idle movement of the ratchet 21. The operations described above can therefore be repeated for the required number of times, and for each of the screws 11, in

order to obtain the required degree of tightening of the wheel R. During tightening, the load limiter of the hydraulic jack is inserted in order to ensure that the limits of tightening of the screws 11, lla are observed, avoiding the risk of breakage of the latter.

To loosen the threaded means 11, lla, the procedure is analogous to that described above, with the sole difference that the operating device 10 must be tilted as indicated by the arrows U1, U2 and U3 in Figure 1, in such a manner that the actuation of the hydraulic jack 25 causes rotation in an anticlockwise direction of the lever 22. As already stated, the ratchet 21 must also be fitted in the reverse direction inside the shaped end of the cylindrical bar 14 in order to obtain the desired effect. In the case where the operating device 10 is used for loosening threaded means which are particularly tight or jammed, it is possible to disengage the load limiter of the jack 25 so as to allow the latter to exert the maximum power and therefore transmit all the available torque to the wrench 16.

In relation to the operating device described above, many variants may be adopted. For example, if an external power source is available, the hydraulic jack 25 can be substituted by a pneumatic jack or by a linear actuator with electric motor. A particularly simplified variant, that can be used when the tightening and loosening torques are not high, is illustrated in Figure 3 and comprises a threaded connecting rod 30 articulated on the end of the lever 22a. Onto the connecting rod 30 is screwed a reaction plate 31 which bears on the support bar 12.

Preferably, the wall of the reaction plate 31 which bears on the bar 12 has a curved profile to ensure secure bearing

independently of the position assumed by the threaded bar 30 in the course of the operations of tightening or loosening the screws or nuts.

Other possible variants of the operating device in Figure 1 relate to the ratchet 21 which could also be of a reversible type, known to experts in the field, and which can be reversed by means of a mechanical control, for example with a lever or push button. As an alternative to, or in addition to the load limiter on the hydraulic jack, there can be provided a generally known limiting device, for example of the mechanical type with spring, coupled to or integral with the ratchet 21.

In the simpler version of the operating device 10, the distance between the bars 13, 14 is fixed and corresponds, for example, to the standard measurement between two screws, adjacent or not, for fixing the wheels of a vehicle to the respective axle, as illustrated by way of example in Figure 1.

However, it is possible to arrange a device with two or more idle arms 13, 13a (Figure 4) in order to adapt to two or more predetermined distances between the screw which acts as the support and reference of the device and that screw which is to be loosened or tightened. As illustrated in Figure 5, finally, it is also possible to produce a variant in which the idle arm 13 is fixed to a carriage 32 slidably mounted on the support bar 12, so as to be able to adjust the distance between the arms 13, 14 as required.

In a further variant of the operating device 10, shown in detail in Figures 6 and 7, the lever 22a is selectively detachable from the arm 14 so that it can be reversed and mounted alternatively in the loosening (Figure 6) or tightening

(Figure 7) configuration of the operating device. Preferably, the lever 22a is axially fixed onto the arm 14 by means of a wing nut 40 which allows fast reversal of the lever 22a. In these figures it is also shown a variant of the support structure of the operating device 10, wherein the two tubular sleeves 18a, 18b are connected by a plurality of transverse reinforcing bars 41.

The fact that, on the ends of the arms 13, 14, means are provided for housing, fitted in, the wrenches 15 and 16 ensures remarkable versatility of the operating device of the present invention. Apart from the interchangeability, already mentioned, of the measurement and of the type of wrenches that can be used, it is also possible to mount on the idle arm 13 a reference device of a different type, for example a vice or a clamp, in such a manner as to be able to use the operating device even in the event that a reference nut or screw 11 distinct from that to be tightened or loosened lla is not available.

Naturally, the principle of the invention remaining the same, the forms of embodiment and details of construction may be varied widely with respect to those described and illustrated, without thereby departing from the scope of the present invention.