A BOLT AND BASE UNIT ASSEMBLY AND A VALVE COMPRISING SUCH AN ASSEMBLY

FIELD OF THE INVENTION

The present invention relates to a bolt and base unit assembly comprising a bolt and a base unit, the bolt and the base unit being adapted to be assembled by means of mating threads formed on the bolt and the base unit, respectively. More particularly, the present invention relates to such an assembly in which it is possible to unthread the mating threads without risking that the bolt and the base part become separated. Furthermore, the present invention relates to a valve comprising an assembly as defined above.

BACKGROUND OF THE INVENTION

When a bolt is used for assembling parts of a device, e.g. a valve housing and a cover for the valve housing, it is desirable to be able to release the assembly in order to provide maintenance for the device. However, when the bolt is released there is a risk that the bolt is dropped by the service personnel performing the maintenance. This results in two major drawbacks. The bolt may be missing when the device is to be reassembled after completion of the maintenance, thereby making it difficult or even impossible to reassemble the device, and the bolt may be dropped onto parts of the device which may break when being hit by the bolt. It is therefore desirable to be able to release the bolt while preventing that the bolt is dropped.

SUMMARY OF THE INVENTION

It is, thus, an object of the invention to provide a bolt and base unit assembly comprising a bolt and a base unit, in which the bolt is allowed to be loosened from the base unit without risking that the bolt is dropped.

It is a further object of the invention to provide a valve in which maintenance of the valve is possible while it is ensured that the valve can be assembled when the maintenance has been completed.

According to a first aspect of the invention the above and other objects are fulfilled by providing a bolt and base unit assembly comprising:

- a bolt having a threaded portion and a bolt head adapted to engage with a driving tool for driving the threaded portion of the bolt into engagement with a mating thread, the bolt head comprising a first abutment portion, and

- a base unit defining a recess comprising a threaded portion, said recess being adapted to receive a bolt in such a manner that the threaded portion of the bolt and the threaded portion of the base unit engage, the base unit comprising a second abutment portion,

wherein the first abutment portion and the second abutment portion are adapted to cooperate in deforming the second abutment portion when the bolt is received in the recess of the base unit, said deformation being sufficient to prevent the bolt from leaving the recess.

In the present context the term 'bolt' should be interpreted to mean an item comprising a threaded portion adapted to threadedly engage a mating thread, and a bolt head comprising one or more drive surfaces adapted to engage with a driving tool in such a manner that operating the driving tool when it engages the drive surface(s) will cause rotation of the bolt, thereby causing the threads to engage. The bolt is preferably of the kind which is suitable for attaching two items to each other.

The base unit matches the bolt in the sense that the threaded portion formed in the recess of the base unit is shaped and sized in such a manner that the threaded portion of the bolt fits therein. Accordingly, the

bolt and the base unit can be attached to each other via the threaded portions, thereby forming the bolt and base unit assembly.

The first abutment portion and the second abutment portion are adapted to cooperate in deforming the second abutment portion when the bolt is received in the recess of the base unit. The deformation is sufficient to prevent the bolt from leaving the recess. Accordingly, when the bolt is initially introduced into the base unit, the second abutment portion will automatically be deformed. Thereby the bolt is prevented from leaving the recess. Furthermore, it may still be possible to unthread the threaded portions, thereby disassembling two parts which are held together by means of the bolt. Thus, once the bolt has been introduced in the recess of the base unit, it can no longer be separated from the base unit. Thereby it is not possible that the bolt is dropped or lost, even if the threads are loosened. This is very advantageous.

The deformation may be caused due to a specific design of the first abutment portion and/or of the second abutment portion. Thus, the deformation may be the result of a specific design of the first/second abutment portion abutting a second/first abutment portion of a 'normal' design. Alternatively, the first abutment portion as well as the second abutment portion may be designed in a specific manner, and the deformation of the second abutment portion may occur as a result of abutment of two specifically designed abutment portions. Such specific design may include specific shapes, sizes, protrusions, material properties, etc., as long as it is ensured that the second abutment portion will deform sufficiently to prevent the bolt from leaving the recess once it has been inserted therein.

The base unit may comprise a base part and a flange part, the flange part being detachably mounted to the base part by means of the bolt, the second abutment portion being formed on the flange part. According to this embodiment, the base unit comprises two detachable parts, i.e. the

base part and the flange part. Preferably, these two detachable parts are held together by means of the bolt. Since the second abutment portion is formed on the flange part, the bolt is prevented from becoming detached from the flange part once it has been inserted therein, as described above. However, it may still be possible to detach the flange part from the base part, e.g. by releasing the threaded connection between the threads of the bolt and the recess. In a preferred embodiment, the base part may be or form part of a housing, e.g. a valve housing, and the flange part may be or form part of a covering part, e.g. a valve cover. In this case, it will be possible to gain access to the interior of the housing, e.g. in order to perform maintenance, without risking that the bolt is lost or dropped while the base part and the flange part are detached. Thereby it is ensured that the parts can be reassembled, and it is prevented that the bolt is dropped onto something which may break.

The threaded part of the recess may be formed in a part of the recess being arranged in the base part. According to this embodiment the bolt may be screwed into the base part while pressing the flange part against the base part, thereby holding the two parts together.

The recess may comprise a non-threaded portion formed in the flange part, said non-threaded portion being sufficiently large to accommodate the threaded portion of the bolt. This embodiment preferably functions in the following manner. When the bolt has been inserted into the threaded portion of the recess of the base unit as described above and the deformation of the second abutment portion is occurring, thereby preventing the bolt from leaving the recess, the bolt preferably holds the base part and the flange part together. If it is desired to detach the flange part from the base part, e.g. in order to perform maintenance, the connection between the threaded portion of the bolt and the threaded portion of the recess in the base part is released. As the threaded portion of the bolt thereby leaves the threaded portion of the recess, it will be received in the non-threaded portion of the recess in the flange part. Since

the non-threaded portion of the recess is sufficiently large to accommodate the threaded portion of the bolt, it is possible to completely disconnect the threaded portions. Accordingly, it is ensured that the base part and the flange part can be detached from each other.

The non-threaded portion of the recess may be arranged between the threaded portion of the recess and the second abutment portion. According to this embodiment, the threaded portion of the bolt can be accommodated in a part of the recess which is arranged in the flange part, and between the threaded portion of the recess and the deformed second abutment portion.

The first abutment portion may be provided with an annular part arranged to push against and deform an edge portion of the second abutment portion, thereby causing the deformation of the second abutment portion. According to this embodiment, the deformation of the second abutment portion occurs as a result of a specific design of the first abutment portion. Thus, the first abutment portion is, in this case, provided with a part which will press against the edge portion of the second abutment portion, thereby deforming it. The deformation preferably causes at least part of the edge portion to bend inwards, thereby narrowing the opening through which the bolt was initially introduced. Thereby the bolt is prevented from leaving the recess.

As an alternative, the second abutment portion may be provided with a protruding part, and the first abutment portion may be arranged to push against and deform the protruding part, thereby causing the deformation of the second abutment portion. According to this embodiment, the deformation of the second abutment portion occurs as a result of a specific design of the second abutment portion. The second abutment portion is, in this case, provided with a part which is deformed when being pressed against the first abutment portion. The deformation preferably causes at least part of the protruding part of the second abutment portion to bend

inwards, thereby narrowing the opening through which the bolt was initially introduced. Thereby the bolt is prevented from leaving the recess.

As another alternative, the deformation of the second abutment portion may occur as a result of a specific design of the first abutment portion as well as a specific design of the second abutment portion, e.g. a combination of the embodiments described above.

The bolt may comprise a non-threaded portion arranged adjacent to the threaded portion, e.g. between the threaded portion of the bolt and the bolt head. Preferably, the deformation of the second abutment portion is such that the non-threaded portion of the bolt is allowed to pass the deformation, while the threaded portion of the bolt is prevented from passing the deformation. Thus, the bolt will be movable relatively to the base unit, in particular relatively to the base part, e.g. in order to release the connection between the threads, but it will not be possible to completely remove the bolt from the base unit. In particular, it will not be possible to detach the bolt from the flange part.

The non-threaded portion of the bolt may have a length which is equal to or longer than the length of the threaded portion of the bolt. Thereby it is ensured that the threaded portion of the bolt can be accommodated in a part of the recess which accommodates the non-threaded portion of the bolt when the threaded portions of the bolt and the recess are threadedly engaged. Thereby it is possible to completely disengage the threads.

The bolt is preferably of standard size, e.g. having a diameter at the part of the threaded portion arranged furthest away from the bolt head which is between 4 mm and 8 mm. As mentioned above, the non-threaded portion of the bolt preferably has a diameter which is slightly smaller than the diameter of the threaded portion. The threaded portion of the recess matches the threaded portion of the bolt in order to allow the threaded portions to threadedly engage as described above. The diameter of the

non-threaded portion of the recess is slightly larger than the diameter of the threaded portion of the recess in order to allow the threaded portion of the bolt to pass there through in order to reach the threaded portion of the recess.

The deformation of the second abutment portion may result in beading of the second abutment portion. Alternatively, the deformation of the second abutment portion may be of any other suitable kind, as long as it prevents the bolt from leaving the recess.

According to a second aspect of the invention the above and other objects are fulfilled by providing a valve comprising a bolt and base unit assembly according to the first aspect of the invention.

It should be noted that a skilled person would readily recognise that any feature described in combination with the first aspect of the invention could also be combined with the second aspect of the invention, and vice versa.

The valve is preferably made from a metal or an alloy, such a brass, steel or stainless steel. However, other suitable metals or alloys could be used.

It is an advantage to use a bolt and base unit assembly according to the first aspect of the invention in a valve, since it is thereby possible to perform maintenance on the valve without risking that the bolt is lost or dropped during the maintenance. This has been described in detail above.

The base unit of the bolt and base unit assembly may comprise a base part being or forming part of a valve housing and a flange part being or forming part of a cover. According to this embodiment, the cover is preferably attached to the valve housing be means of the bolt, and the bolt is prevented from leaving the cover due to the deformation of the second abutment portion. Accordingly, the valve housing and the cover may be separated, thereby providing access to the interior of the valve housing,

e.g. for performing maintenance, without risking that the bolt is lost or dropped. The valve may comprise several assemblies, e.g. in the form of several bolts used for attaching one cover to one valve housing.

The cover preferably has a surface area which is larger than or equal to 30 mm by 30 mm, such as 65 mm by 65 mm, or 100 mm by 100 mm. The valve housing preferably has a surface with an area which matches the surface area of the cover.

The valve may be a magnetic valve, such as a solenoid valve. Alternatively, it may be any other suitable kind of valve.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in further detail with reference to the accompanying drawings in which

Figs. 1a-1c illustrate a bolt and base unit assembly according to a first embodiment of the invention, and

Figs. 2a-2c illustrate a bolt and base unit assembly according to a second embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Figs. 1a-1c illustrate a bolt and base unit assembly 1 according to a first embodiment of the invention. The assembly 1 comprises a bolt 2 and a base unit 3. The bolt 2 comprises a bolt head 4, a non-threaded portion 5a, and a threaded portion 5b arranged opposite the bolt head 4. The base unit 3 comprises a base part 6 and a flange part 7, the flange part 7 being adapted to be detachably mounted to the base part 6. This will be described in further detail below. The base unit 3 defines a recess 8 having a non-threaded region 8a and a threaded region 8b. The threaded region 8b is formed in the base part 6 and the non-threaded region 8a is

formed in the flange part 7. The bolt head 4 is provided with an annular part 9.

The function of the assembly 1 of Figs. 1a-1c will be described in the following. Fig. 1a shows the assembly 1 in a detached state prior to assembling the bolt 2 and the base unit 3. Thus, the bolt 2 is shown in a position above the base unit 3. When it is desired to assemble the assembly 1 , the bolt 2 is inserted into the recess 8, and the threaded portion 5b of the bolt 2 threadedly engages the threaded portion 8b of the recess 8 until the bolt head 4 abuts an abutment region 10 of the flange part 7. This is illustrated in Fig. 1 b.

When the bolt head 4 is moved into abutment with the abutment region 10 as shown in Fig. 1 b, the annular part 9 presses against the abutment region 10, thereby deforming it by bending part of it inwards, i.e. beading part of the abutment region 10. This is clearly illustrated in Fig. 1b. The deformation is sufficiently significant to prevent the threaded portion 5b of the bolt 2 from passing the deformation, and thereby it is no longer possible to detach the bolt 2 from the flange part 7. However, the non- threaded portion 8a of the recess 8 is sufficiently large to accommodate the threaded portion 5b of the bolt 2, and it is therefore possible to release the threaded engagement between the threaded portions 5b, 8b completely, thereby detaching the flange part 7 from the base part 6. This situation is illustrated in Fig. 1c.

Accordingly, it is possible to detach the base part 6 and the flange part 7, e.g. in order to perform maintenance, without risking dropping or loosing the bolt 2. This is very advantageous.

Figs. 2a-2c illustrate a bolt and base unit assembly 1 according to a second embodiment of the invention. The embodiment of Figs. 2a-2c is similar to the embodiment of Figs. 1a-1c, and the function of the bolt and base unit 1 will therefore not be described in detail here.

Similarly to Fig. 1a, Fig. 2a shows the assembly 1 in a detached state prior to assembling the bolt 2 and the base unit 3. The flange part 7 is provided with a protruding part 11. When the bolt 2 is inserted into the recess 8 and the threaded portions 5b, 8b are caused to engage, an abutment region 12 of the bolt 2 will eventually abut the flange part 7. This will cause the protruding part 11 to deform by bending inwards, i.e. beading the protruding part 11. This is illustrated in Fig. 2b.

The deformation of the protruding part 11 is sufficiently significant to prevent the threaded portion 5b of the bolt 2 from passing the deformation. However, the non-threaded portion 8a of the recess 8 is sufficiently large to accommodate the threaded portion 5b of the bolt 2 as illustrated in Fig. 2c. Accordingly, the advantages described above with reference to Figs. 1a-1c are also obtained in this case.