Device and method for loosening a sticking connection

The present invention relates to a device and method for loosening a sticking 5 connection. More in particular, the invention relates to a device and method for loosening and removing atomisers from the cylinder head of an engine.

In non-prepublished International Patent Application PCT/NL2005/000629, filed on 31 August 2005 and meanwhile published on 9 March 2006 under No. WO 2006/025736, a method and device were disclosed for loosening a sticking connection in

10 an engine block, in particular a glow plug. The device comprises a mechanism for generating axial vibrations, preferably pneumatically, hydraulically or electrically, as well as means of transmitting these vibrations on the sticking connection, and the device comprises also means to exert a couple on the connection to be loosened, which couple preferably can be read-off or is pre-adjustable. According to this method the connection to

15 be loosened is subjected to axial vibrations and at the same time a couple is exerted in order to loosen it. A particular embodiment of the principle of this method and device is illustrated in Figures 8 and 9 of said patent application, which have now been incorporated in somewhat adapted form in the present patent application as Figures 1 and 2, respectively.

20 With reference to these figures a device is now shown for generating axial vibrations in combination with an adapter, which is suitable for vibrating loose and removing an atomiser 25, which is inserted in a cylinder head 32.

The atomiser 25 having a spray nozzle 35 is inserted into a combustion chamber. The nozzle 35 extends through a hole 34 and is in principle sized such that no

25 combustion gas flows through the small play between the nozzle 35 and the hole 34. Usually, it still happens by the nature of the combustion process and as a result combustion gases flow into the small gap 33 between the cylinder head 32 and the atomiser 35. These combustion gases cool down and are deposited as materials fixing the atomiser 25 in the cylinder head 32 such that pulling out often becomes problematic.

30 The atomiser 25 is provided at the upper end with a thread 41 , on which a tension spindle 28 with a centre line 36 can be screwed. In the inside of the tubular outer wall of the atomiser 25 various parts are mounted, so that the thickness of its wall is limited and the atomiser can break down upon applying a too strong force on the tension spindle 28. It is then no longer possible to pull out the atomiser 25 from the cylinder head

35 32 in a normal way.

In order to be able to pull out the atomiser as yet, a vibration is applied on the tension spindle 29 in accordance with the previous patent application using a vibration rod 14 with a centre line 37, wherein the direction of the vibration is angled with the centre line 36 of the tension spindle 28, thereby causing vibrations both in the longitudinal and transverse direction. In particular, the vibration in transverse direction is very effective on the small gap 33. The vibration rod 14 is designed with a slant end, usually with an angle of 45° with respect to the centre line 37 of the vibration rod 14, which preferably is directly engaged to the atomiser 25 or the tension spindle 28. The tension spindle 28 as depicted here is derived from a conventional type and comprises a casing 26, a bearing 30, a support 31 and a nut 29 which is screwed on a thread 38 of the tension spindle 28. The tension spindle 28 comprises key planes 39 for screwing on the atomiser 25. The casing 26 is supported on the cylinder head 32 through a bush 40.

This type of tension spindle is known to a person skilled in the art (see, e.g., DE 20 2994 009 755 U1) and will therefore not be described herein in further detail. A guide bush 27 is mounted in the casing 26 to guide the slant vibration rod

14, thereby enabling the vibration rod 14 to exert vibrations on the atomiser 25 via the tension spindle 28. It will be clear to a skilled person that the atomiser 25 will undergo vibrations in various directions, in view of the angle between the centre line 26 of the atomiser and the centre line 37 of the vibration rod 14. Since the atomiser 25 is not screwed, it can be loosened and removed by axial force, for example by turning the nut 29.

Although the embodiment of this method and device described in the above- mentioned, non-prepublished international patent application is very suitable for loosening and removing atomisers from a cylinder block of an engine, extensive further research resulted in an improvement of the device, with which atomisers can be loosened and taken out by vibration even more effectively and with still a lower chance on breaking down.

It has now surprisingly been found that this improvement can be reached by designing the device in accordance with claim 1. By applying the spring means a tension force is exerted on the elongated object which is more or less independent from the displacement of said elongated object, even after the elongated object underwent a very small displacement with respect to the holder.

By pulling the elongated object and at the same time applying slant vibrations of the elongated object, as described above with reference to Figure 1 and Figure 2, the gap between the elongated object and the holder will experience continuous changes in its size resulting in a disrupture of the pollutants which are present between the two parts. This structure will be disrupted in particular where it is under tension. If a local connection

between the holder and the elongated object is disrupted by the high tension and vibration, a subsequent local connection will experience high tension by the spring force applied and will also disrupt. Accordingly, the elongated object will undergo continuously very small displacements, but will at last be freed from the holder. The present invention is based on the finding that the elongated object is to be pulled out by applying vibrations both in longitudinal and transverse direction while exerting continuous tension force.

An embodiment of the device is in accordance with claim 2. By employing a holder with Belleville washers as spring means it will now be possible to adapt the spring means to the occurring conditions in a simple way.

An embodiment of the device is in accordance with claim 3. This prevents the coupling rod from shooting away under the influence of the spring means.

The invention relates also to a method as defined in claim 4. By using this method a sticking object will be pulled out from a hole in a rapid way. An embodiment of said method is in accordance with claim 5. This will further accelerate the pulling out of the object.

The working duration is not particularly critical and normally takes from one minute to several minutes, depending on the degree of corrosion and/or carbon depositing and the frequency of the axial vibration mechanism. Preferably, prior to and/or during vibration penetrating oil or an equivalent is applied to the gap 33. In a preferred embodiment of the device, the impact/vibration frequency can be adjusted. A suitable setting has, for example, a frequency in the range of around 3000-8000 vibrations/minute, preferably around 4000-6000 vibrations/minute, and most preferably around 5000 vibrations/minute. The invention will now be illustrated further by the following embodiment which however does not limit the invention in any respect, and with reference to the accompanying drawings, in which:

Figure 1 is a schematic perspective view of an axial vibration device, as disclosed in PCT/NL2005/00629, with an adapter suitable for loosening and removing atomisers by vibration;

Figure 2 is a schematic cross-section of the device and adapter according to Fig. 1 ; and

Figure 3 is a schematic cross-section of part of the device according to Figure 2 under the addition of spring means according to the invention. Figure 3 differs from Figure 2 in that the tension spindle 28 is now equipped with a package of Belleville washers with accessories, which will be discussed below in more detail.

It should be noted that for the sake of clarity in the various figures the same reference numbers are used as far as possible for the same or equivalent components.

Figures 1 and 2 have been extensively described above, so that no further explanation will be given here. For further details, reference is made to PCT/NL2005/ 000629, which is incorporated herein by reference.

Figure 3 shows the vibration device corresponding to the vibration device of Figure 2, as previously discussed. The tension spindle 28 is made longer, so that the nut 29, which also in this case is screwed on the thread 38 at the end of the tension spindle, will rest on a spring assembly 47. The spring assembly 47 rests on the support plate 31 via a sleeve 46, in a similar way as in the embodiment of Figure 2 by the nut 29.

The spring assembly 47 comprises a casing 45, in which a plurality of Belleville washers 44 is mounted, six washers in the embodiment illustrated. The casing 45 is designed with a cylindrical inner wall, the inner diameter being such that the Belleville washers 44 can move freely, also in loaded condition, and the Belleville washers 44 are restraint within the casing 45 by two spring rings 42. In the embodiment shown always three Belleville washers 44 are positioned opposite each other; by using a smaller amount of Belleville washers 44 and/or grouping them in a different way with respect to each other, the spring assembly can be given another degree of rigidity, thereby enabling the device to be adapted to a specific situation. In order to prevent that the tension spindle 28 may shoot away under the influence of the power present in the spring assembly 47, a retainer washer 45 may be applied around the tension spindle 28. The retainer washer 45 is located between the Belleville washers 44 and is therefore retained, so that the tension spindle is limited in its free movement. It will be understood by a person skilled in the art that modifications and adaptations to the device described in the present patent application can be made without deviating from the essence of the invention. Such modifications and adaptations, some of which are set out above, are therefore included in this invention. For example, the retainer washer 45 may also be mounted under the bearing. Also, there is no need that the spring assembly would rest on the support plate through a sleeve 46, but it may form an integral part with the support plate. The guide bush 27 may also be omitted; the frame may adopt the guiding features. The Belleville washers may be placed on the bearing by means of a ball plate. The springs will transmit the force with a certain frequency of vibration. A person skilled in the art may easily establish experimentally an optimal combination of appropriate Belleville washers in order to obtain the greatest efficiency for loosening the atomiser by

vibration. Advantageously, a suitable liquid such as an oil, for example a penetrating oil, is added in order to improve and/or to accelerate said loosening process.