Technical Field.

The object of the present invention is a system as well as tools for the screwing and unscrewing of threaded elements, in particular for the assembly and dismantling of the wheels of vehicles onto or off the hub of a wheel, without any effort on the part of the operator, who participates only in the activation phase and during the checking of the operation.

Background Art. The problem of being able to replace easily and rapidly the wheel of, for example a car, is becoming more and more serious. The tools used today mostly need a lot of strength, especially if the operation is carried out manually, thus making the assembly and dismantling difficult and timewasting.

It is well-known that when you try to screw or unscrew a nut, a bolt or any other threaded element, it is necessary to provide a resisting torque, while if the tool, has its own motor, the torque that must be provided by the operator can mostly be limited to a resisting type, in the sense that in this case the operator has the task of keeping the tool

constantly engaged on the threaded element that must be unscrewed or tightened.

Often in either case the problem is that the maneuver may fail, especially if the situation is not evaluated correctly and one tries to unscrew a nut or a bolt that is too tight, because the toll becomes disengaged from the head of the threaded element.

Generally, and especially in the case described above, if the forcing action along the external perimeter of the head of the threaded element is not homogeneous, the head will be damaged and with the passing of time the problem of disengagement between the spanner and the head of the threaded element during screwing and unscrewing becomes worse.

The obiect and important characteristics of the invention.

One of the aims of the present invention is, in the first place, that of reducing or eliminating the necessity for an active participation of the operator, so that his part in the operation will be limited to activating and controlling the screwing and tightening operation. Another aim of the present invention is to propose a tool that is structurally simple, small in size and cheap to make. Another aim of the present invention is that of making a tool capable of working perpendicularly to the axis of the threaded element, engaging it safely and precisely in order to avoid non-homogeneous forcing actions along the

external perimeter of the head of the threaded element and possible damage or disengagement of the same. Another aim of the present invention is to reduce the effort needed for the operation of dismantling and assembling wheels from the hubs of vehicles and to make the operation safer and more controllable. These aims are reached through a system which includes a tool formed by a normal mechanism with an electric or an automatic pneumatic motor with a rotating axis to screw or unscrew threaded elements by using a spanner placed on the end of and provided with a further spanner, placed on and bound to the shell of the tool and which presents, in the first example of this invention, male longitudinally profiled male grooves, designed to be inserted into holes opportunely profiled with longitudinal female grooves, coaxial to the hexagonal headed pins that are to be tightened. The utensil is then fitted into each opportunely profiled hole, in a light alloy rim designed to hold the tyres of an automobile wheel so that the spanner placed on the end of the utensil matches the pin that is to be activated and the spanner with the male grooves engages the female grooves of the hole. It is therefore understood that the operator, due to the binding effect of the external shell of the utensil, which is guaranteed by the matching of the utensil shell/hole, need make no effort during screwing or unscrewing, because the torque is given by the utensil motor and the resisting torque is conferred by the aforesaid binding action of the

utensil shell/ profiled hole, coaxial to the pin which is to be secured. In this way the whole operation of screwing and unscrewing becomes faster and safer. When it is not possible to profile the holes in order to bind the spanner placed on the shell of the utensil, special accessories to create the binding action, which is the object of this invention, can be used.

Description of the drawings and mode for carrying out the invention.

Further characteristics and advantages of the present invention will appear more evident in the detailed description which follows, of some favoured but not exclusive forms of realisation, illustrated in a purely indicative, but not limiting qualification, in the attached drawings in which :

Fig.l) shows a schematic lateral view of the tool in accordance with the present invention.

Fig.2) shows a schematic drawing of an automobile wheel modified to use the present invention.

Fig.3) shows the mechanical component made up of the rim of an automobile wheel with holes profiled and coaxial to the pins that are to be secured.

Fig.4) shows a tubular accessory with indentations around the circumference of one end, to be assembled on the other end of the tool.

Fig.5) shows the self-blocking washer.

Fig.6) shows the tubular accessory assembled on the tool and ready to operate on a nut.

Fig.7) shows an accessory for use with the tool when the use of multiple profiled holes is not foreseen. Fig.8) shows another plate-shaped accessory, with double holes specifically profiled.

(1) indicates a portable utensil, activated by a switch (2), which has an electric or pneumatic motor with a rotating axis for screwing or unscrewing threaded elements by using a spanner placed on the end of (3 ) and which is also provided with a further spanner which, in the case of Fig.l, presents profiled longitudinal grooves (4), and which is coaxial with and onto the shell of the utensil (1). In a more general sense, the aforesaid mechanical connection, which permits the binding of the shell of the utensil ( 1 ) can be obtained, in other examples of the present invention, by using tabs, pins, profiled holes, radial grooves, internal box- spanners, with electromagnetic or other types of bonds. (5) indicates the mechanical component with specifically profiled holes (6) which have longitudinal female grooves, coaxial to the hexagonal headed pins, (7) to be secured. This mechanical component is a light alloy rim designed to hold the tyres (8) of an automobile wheel. The utensil ( 1 ) is fitted in the hole so that the spanner placed on the end of (3) matches the pin (7) that is to be activated, and the spanner with the male grooves (4) engages the female grooves of the hole (6). The binding effect of the external

shell of the utensil ( 1 ) is thus guaranteed by the spanner (4)/hole (6) match.

(9) indicates an accessory device, capable of matching, at one extreme (10), by using a simple joint, the spanner (4) placed on the external shell of the utensil ( 1 ) and provided at the other extreme with indentations (11). (12) indicates an indented washer which is designed to fit the indentations of the accessory (9), the washer ( 12) is placed between the component to be secured (wheel or other mechanical component) and the nut or bolt ; the indentations on the extremity (11 ) form a radial join with the washer ( 12) which binds because of the friction generated between the pin and the component to be secured or with the pin taken from the central hole in the lower face or on the external circumference. This application is particularly indicated when there is only one threaded element to activate and there is not enough thickness or it is not convenient to make profiled holes as in (6). When there are several nuts or bolts to works on and particularly when, on the rims of the automobile wheels there are no binding holes (6) it is possible to arrange a specific device on which profiled holes are made (6) with which it is possible to obtain generic mechanical connections with tabs, pins, profiled holes, longitudinally and/or radial grooves, internal box spanners etc. The component (13) obtained in this way, fits directly onto the draw bolts (7) and/or between the pins and the component to be

tightened. While working, the utensil (1 ) is fitted in each hole (6) and the transmission of the moment from the mechanical component to the utensil ( 1 ) is guaranteed by the spanner (4)/hole (6) match. ( 14) indicates a further accessory for the utensil ( 1 ) to be assembled on the spanner (4). The accessory consists of an elongated rectangular plate, on the extreme of which there is a hole, profiled with grooves and trapezoidal teeth, ( 15) or with a box spanner, designed to insert into and to bind onto the spanner (4) while on the other extreme of the aforesaid plate, a slotted hole has been made ( 16) through which a box spanner may run ( 17). With this accessory ( 14) the utensil (1) is capable of binding itself onto the heads of the pins on which it is working (two or more pins), without any effort on the part of the operator.