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SPARKING PLUG SCREWING/UNSCREWING TOOL WITH HOUSING FOR A SPARE SPARKING PLUG AND EXTENSION SPANNER BUSH.

DESCRIPTION 5 Field of the invention

The present invention generally relates to a tool for engines and more precisely it relates to a sparking plug screwing/unscrewing tool with housing for a spare sparking plug and extension spanner bush. 10 Description of the prior ar

Sparking plugs must be periodically checked and changed when worn out. In fact, one of the possible causes of bad running of the engines is due either to a bad ignition normally caused by a worn-out sparking plug or to 15 the presence of dirt or oxides deposited on the electrodes from where the spark originates.

Replacement of sparking plugs is a very simple operation that can be carried out by everybody, provided a suitable tool is available. However, this operation is 20 normally carried out by a mechanic during the periodical overhauling of the engine, even though in case of bad running of the engine, the user can do it without any particular difficulties, by using the equipment tools normally provided with the engine, including a plug box 25 spanner and a spare sparking plug. This happens often to motorists, e.g. in case of failure of the ignition of a cool engine when starting.

On the contrary, in many other instances, such as in case of motorcycles, small agricultural machines e.g.

30 hedge trimmers, power mowers, chainsaws, rotavators, as well as in case of generator units, the equipment described above is not available.

For these reasons, the users of such devices usually keep a suitable tool and at least a spare sparking plug in

- 2 - order to fix the engine in case it doesn't start. Summary of the invention

It is an object of the present invention to provide a sparking plug screwing/unscrewing tool which also

5 includes a spare sparking plug so that its use is particularly easy and convenient in several different operating conditions.

It is another object of the present invention to provide a sparking plug screwing/unscrewing tool which is 0 also particularly suitable for being carried by the user together with a spare sparking plug as a single article, e.g. carried in a pocket or tied with a strip around the neck.

According to the present invention, the above 5 objects are achieved by a sparking plug screwing- unscrewing tool having an elongated handle with a ring spanner-shaped end suitable to engage with an hex nut. Its characteristic is that the handle comprises an inner housing in which at least a portion of a spare sparking 0 plug may engage and which is accessible from an open end opposite to the spanner-shaped end. Plugging means are provided for engaging with said open end thus blocking said spare sparking plug.

Preferably an extension bush having a male spanner 5 end and a female spanner end is provided, the former being suited to engage with said ring spanner-shaped end of said handle and the latter being suitable to screw/unscrew a sparking plug engaging with its hex nut. The extension bush can be made preferably in a metal for tools. 0 Advantageously, the handle's ring spanner-shaped end is made of metal for tools, the other part of the handle being made of plastics.

The plugging means comprises either the extension bush, which is introduced into the housing through the

open end beginning from said female end, or a hollow plug in which, in use, a portion of the spare sparking plug projecting from said housing engages. Externally the plugging means may comprise a sealing ring engaging, in use, with an internal portion of the housing.

The inner housing of the handle comprises preferably an annular spanner ring portion with which either the male end of the bush or the hex nut of the sparking plug engages. Further characteristics and advantages of the tool according to the present invention will become apparent in the following description of one of its possible embodiments, given as an example and not limitative, with reference to the attached drawings in which: - figure 1 is a partially exploded sectioned longitudinal view of a tool according to the invention;

- figure 2 shows the tool of figure 1 in a first operative configuration;

- figure 3 shows the tool of figure 1 in a second operative configuration;

- figure 4 shows the tool of figure 1 in a third operative configuration;

Description of the preferred em odiment

With reference to figure 1, a sparking plug screwing/unscrewing tool according to the present invention comprises an elongated handle 1 with an end 2 having a ring spanner-shaped portion 3 suitable to engage with an hex nut of a spare sparking plug. Handle 1 further comprises a inner housing 4 accessible from an open end 5 opposite to the spanner-shaped end 2 and in which at least a portion of a spare sparking plug 6 can engage.

More precisely, ring spanner-shaped end 2 comprises a metal block 3a having the ring spanner portion 3 and a bottom wall 8 with a through hole 8a coaxial to ring

- 4 - spanner portion 3. Metal block 3a is embedded in a recess 2a provided for in end 2 of handle 1, so that the latter and block 3a form together one body. Block 3a may be forced into recess 2a which may be made for example during 5 a compression moulding production of handle 1 itself. The diameter of the ring spanner portion 3, e.g. 21 mm, depends on the type of sparking plug used in the engine, normally available in several different standard sizes depending on the type of engine. In case of wear of ring 0 spanner portion 3 wears out, block 3a can be extracted from recess 2a to be changed by pulling it through two holes 7 made in end 2 by using a suitable tool.

Advantageously, handle 1 is externally grooved so that the grip is stronger when the user has to screw or 5 unscrew a sparking plug in/from the head of an engine. The external shape of the handle may have rounded corners in order to make its carrying easier, in particular if it is carried by the user, for example in a pocket or tied with a string around the neck. 0 Inside handle 1 housing 4 has been dimensionally shaped in order to contain a portion 6a of sparking plug 6, extending to the screwed portion of the latter and comprising the hex nut 6c. The remaining portion 6b of sparking plug 6, when this is present inside handle 1, 5 leans out housing 4 through open end 5. Housing 4 advantageously presents a ring spanner portion 4c with which the hex nut portion 6c of sparking plug 6 engages. Portion 6a, which is all contained in housing 4, extends coaxially to handle 1 except from end 2. This way 0 according to the invention the whole length of the tool is the minimum possible, corresponding substantially to the length of sparking plug 6 plus the length of spanner- shaped end 2.

Preferably, at least an extension bush 9 is

provided, having a male spanner end 10 and a female spanner end 11. Male spanner end 10 is suitable to engage with spanner-shaped end 2 of handle 1 whereas female spanner end is suited to screw/unscrew sparking plug 6 by engaging with its hex nut 6c. Bush 9, which can be made of either metal for tools or hardened plastics, is substantially cylindrical with axial hollow 12 and with lateral surface having a seal O-ring 13 whose external diameter is not much bigger than the internal diameter of the first portion 4a of housing 4. This way, open end 5 through which housing 4 is accessible can be stopped by bush 9 when it is partially introduced therein beginning from its female end 11. The introduction is possible as far as the end of a second portion 4b against which female spanner end 11 engages. Portion 4b has the same diameter of the external surface of bush 9, and is placed between the first portion 4a and ring spanner portion 4c. While bush 9 is engaging with second portion 4b, O-ring 13 sealingly engages with the cylindrical wall of the first portion 4a, thus preventing dampness and water from reaching sparking plug 6.

Alternatively, open end 5 can be stopped by a plug 15, suitable to house internally, in a hollow 16, portion 6b of sparking plug 6 which extends outwards from housing 4 of handle 1. Plug 15 has a collet 17 projecting from it and comprising an O-ring 18 suitable to sealingly engage with portion 4a of housing 4 of handle 1, in the same way as the above bush 9. Plug 15 is advantageously made of plastics and once it is put in the stop position, at open end 5, it forms one body together with handle 1 and prevents water and dampness from reaching spare sparking plug 6 which is housed inside.

The one body formed by handle 1, spare sparking plug 6 and either bush 9 or plug 15 can be easily handled and

carried either in a pocket or tied with a string around the neck. For this reason, handle 1 advantageously presents an eyelet 19 around which a string can be tied.

A first use configuration of the tool according to the invention is that shown in figure 2, where bush 9 by means of its male spanner end 10 engages with ring spanner portion 3 whilst the hex portion 6c of sparking plug 6 engages with its female spanner end 11. In this position portion 6a of sparking plug 6 extends through all the length of hollow 12 of bush 9 and handle 1 accomplishes the function of actuating lever, capable of forcing on bush 9 so that it screws/unscrews sparking plug 6. In this case, bush 9 acts substantially as an extension element in order to reach sparking plug 6 when it doesn't protrude completely from the head of the engine.

As shown in figure 3, in the same way handle 1 can force on sparking plug 6 even if bush 9 is not present, when the sparking plug completely protrudes from the head of the engine. In fact, hex nut portion 6c of sparking plug 6 can engage directly with ring spanner portion 3, with portion 6a passing through hole 8a of bottom wall 8 of block 3a. This configuration without extension bush 9 is less heavy and less expensive than the first, because open end 5 can be stopped by plug 15 instead of bush 9, which, being made of metal instead of plastics, is heavier than the former. This lighter configuration may be used in case of engines with easily accessible sparking plug, e.g. engines for cross, trial motorcycles and engines for small machines, such as those used in agriculture. Since, housing 4 of handle 1 comprises ring spanner portion 4c, the tool according to the invention can be used also in a third configuration, shown in figure 4. Bush 9 is partially introduced into housing 4 beginning from its male end 10, which thus engages with ring spanner

- 7 - portion 4c. O-ring 13, by pressing against portion 4a prevents bush 9 from easily disengaging from housing 4. Bush 9 is then allowed to operate coaxially to handle 1 so as to engage with hex nut 6c of sparking plug and screw/unscrew it in/from the head of an engine. In order to increase the torque on bush 9 by handle 1, an auxiliary sparking plug 6' may be used, such as the same worn-out sparking plug unscrewed from the engine or the spare sparking plug previously housed in handle 1. More precisely, sparking plug 6' is introduced through ring spanner shaped end 3 and hole 8a as if it had to be screwed somewhere, thus forming a substantially T tool together with handle 1 and bush 9. This configuration is particularly useful when the sparking plug is placed deeply in the engine and cannot be reached by bush 9 in the position of figure 2.

Notwithstanding bush 9 and plug 15 have been shown with O-rings 13 and 18 provided for externally, an equivalent seal can be obtained with housing 4 by providing an O-ring internally engaging with portion 4a of housing 4. This alternative solution would be exactly equivalent to the other one.

The tool according to the invention accomplishes the above objects, because it can be easily used in different configurations, it is less voluminous and is capable of housing at least a spare sparking plug which can be easily screwed/unscrewed without the need of further tools.