WO2012048708A1

WO2012048708A1 - Lubrication device

Info

Publication number: WO2012048708A1
Application number: PCT/DK2010/050271
Authority: WO
Inventors: Carsten Lauridsen
Original assignee: Ringkøbing Maskinværksted A/S
Priority date: 2010-10-15
Filing date: 2010-10-15
Publication date: 2012-04-19

Abstract

A lubrication device is disclosed, comprising a first lubricant distributor comprising a thread lubricator arranged with a plurality of nozzles to inject a lubricant individually into a plurality of grooves of a first thread of a workpiece, which is placed in the lubrication device for being lubricated, thus applying the lubricant to one or more surfaces in each groove of the thread, and a pump for dosing the lubricant reaching the first lubricant distributor. The device may further comprise means for rotating the workpiece around the rotational axis of the thread and/or a second lubricant distributor, which may be a nozzle arranged to apply a lubricant to a surface of the workpiece, such as the underside of a bolt head, or it may comprise a thread lubricator like the one of the first lubricant distributor to apply lubricant individually to one or more surfaces in each groove of a thread.

Description

LUBRICATION DEVICE

Field of the invention The present invention relates to a device for lubricating threads. Background of the invention

It order to prevent seizing of the thread when mounting a bolt or another workpiece, it is advisable to lubricate at least a part of the thread in order to reduce the friction between the external and internal threads, which are to be fitted together. This is especially the case for stretch bolts, in relation to which the thread friction must be reduced significantly due to the large stress loads applied to the threads while stretching the bolt during mounting it.

Historically, such lubrication has been performed by hand using some kind of brush to apply the lubricant, normally some kind of grease or lubricating paste, to the relevant parts of the thread. Other solutions, such as the ones disclosed in US patent No. US 5,743,359 (Parnell) and international patent application No. WO 2005/08857 (Bolt Wax OY), include dipping a bolt into or dragging a bolt through a resilient absorbent material, which has been at least partly saturated with the lubricant. One common problem of such methods is that the amount of lubricant applied to the thread is very difficult to control, often resulting in excessive use of lubricant, the excess lubricant ending up in many different places, where it is absolutely not needed or wanted. Another problem is that the application of lubricant is not uniform and that it is difficult to make sure that all parts of the thread that need lubrication have, in fact, been covered with an appropriate amount of lubricant.

Japanese patent No. JP 2000288446 (Tomita Kazuyuki et al.) discloses a device for applying lubricant uniformly to the thread part of a bolt by supplying lubricant to the bolt and letting one or more brushes rotate a number of times around the bolt while being in contact with the thread, thus spreading the supplied lubricant over the parts of the thread covered by the brushes. Although this solution increases the uniformity of the application of lubricant, there is still a certain uncertainty related to the distribution associated with the use of brushes, and it is not possible to avoid the lubricant from being spread over all surfaces of the thread covered by the brushes, although lubrication may only be needed on some of the surfaces.

It is an object of the present invention to provide a lubrication device without the above-mentioned disadvantages of the solutions known in the art, being able to apply a uniformly distributed and well-defined amount of lubricant only to the surfaces of the thread on which lubrication is needed.

Brief description of the invention The present invention relates to a lubrication device comprising a first lubricant distributor comprising a thread lubricator arranged with a plurality of nozzles to inject a lubricant individually into a plurality of grooves of a first thread of a workpiece, which is placed in the lubrication device for being lubricated, thus applying the lubricant to one or more surfaces in each groove of the thread, and a pump for dosing the lubricant reaching the first lubricant distributor.

By applying lubricant individually into each groove of the thread, a very accurate and uniform distribution of the lubricant can be obtained. If it is desired, it is possible to apply lubricant only to some of the thread surfaces, such as the ones carrying the large stress loads of a stretch bolt, leaving the remaining thread surfaces free of lubricant.

In an embodiment of the invention, the device further comprises means for rotating the workpiece around the rotational axis of the first thread. It has proved to be advantageous to keep the lubricant distributor in a fixed position and rotate the workpiece to be lubricated. However, nothing prevents other solutions, which include moving the lubricant distributor and keeping the workpiece in a fixed position.

In an embodiment of the invention, the device further comprises a second lubricant distributor.

As some workpieces need lubrication in more than one place, it is advantageous to equip the lubrication device with more than a single lubricant distributor.

In an embodiment of the invention, the second lubricant distributor comprises a nozzle arranged to apply a lubricant to a surface of the workpiece, such as the underside of a bolt head.

Some workpieces need to be lubricated on a specific surface, such as the underside of the bolt head of stretch bolts, for instance because this surface must be able to carry large stress loads. Therefore, when working with such types of workpieces, it is advantageous if the lubrication device can be equipped with a lubrication distributor suitable for lubricating such surfaces.

In an embodiment of the invention, the second lubricant distributor comprises a thread lubricator arranged with a plurality of nozzles to inject a lubricant individually into a plurality of grooves of a second thread of the workpiece, thus applying the lubricant to one or more surfaces in each groove of the thread.

Some workpieces, such as stud bolts, have more than one thread that needs lubrication. Therefore, when working with such types of workpieces, it is

advantageous if the lubrication device can be equipped with more than one lubrication distributor suitable for lubricating threads. In an embodiment of the invention, the device further comprises a distributor block for distributing the lubricant from the pump between the first lubricant distributor and the second lubricant distributor. If more than one lubricant distributor is used, the use of a distributor block is a simple and advantageous way to control the distribution of lubricant to each of the lubricant distributors.

In an embodiment of the invention, the distributor block is adjustable for obtaining different distributions of lubricant between the first lubricant distributor and the second lubricant distributor.

Depending on the type of workpiece being lubricated, different distributions of lubricant to the different lubricant distributors may be required. A simple way to make such adjustments possible is to make the distributor block adjustable.

In an embodiment of the invention, at least one lubrication distributor is elastically suspended or spring-loaded. Making the lubrication distributors elastically suspended or spring-loaded helps making it possible to assure that the nozzles of the lubricant distributor(s) are correctly positioned and pressed against the workpiece at a constant and controlled pressure during lubrication. In an embodiment of the invention, at least one thread lubricator is constructed from a number of plates with different through-holes, stacked on top of each other and fixed tightly together.

Using a number of plates stacked and fixed together is a relatively simple and reliable way of obtaining very accurately constructed thread lubricators, which are necessary, especially for lubricating threads uniformly and correct. In an embodiment of the invention, the means for rotating the workpiece comprises a handle for manual rotation of the workpiece. Using a handle and manual rotation makes the lubrication device simpler and cheaper, since no electronics or motors are needed.

In an embodiment of the invention, the means for rotating the workpiece is driven by a motor and arranged to rotate the workpiece automatically at the initiation of a lubrication process, for instance when a button is pressed.

Using a motor-driven rotation makes the operation of the lubrication device easier and more reproducible. In an embodiment of the invention, the means for rotating the workpiece is arranged to rotate the workpiece for a single full rotation.

Since each of the grooves of the thread is lubricated individually, the whole thread has been lubricated, when the workpiece has been rotated by one full rotation (or alternatively when a thread lubricator has been moved for one full rotation in relation to the workpiece). Therefore, it is advantageous if the lubrication process finishes automatically after one rotation.

In an embodiment of the invention, the pump is driven by the means for rotating the workpiece simultaneously with the rotation of the workpiece.

Driving the pump together with the rotation of the workpiece makes sure that the amount of lubricant delivered by the pump to the lubricant distributor(s) is adjusted to the rotational speed, so that the amount of lubricant applied to the workpiece is correct. In an embodiment of the invention, the pump is a gear pump that can be geared in different ways for obtaining different doses of lubricant reaching the lubricant distributor(s) during operation of the lubrication device. It is advantageous if the pump can be geared so that the amount of lubricant delivered to the lubricant distributor(s) during a full rotation of the workpiece can be adjusted depending on the type of workpiece being lubricated.

In an embodiment of the invention, the device further comprises means for pressurising a lubricant source for forcing lubricant from the lubricant source to the pump, for instance by means of pressurised air.

In order to make sure that the pump is always supplied with lubricant, it is advantageous to make sure that the lubricant source is pressurised.

Figures

A few exemplary embodiments of the invention will be described in the following with reference to the figures, of which fig. la illustrates a perspective view of a lubrication device according to an embodiment of the invention, fig. lb illustrates a perspective view of the same embodiment of the invention as shown in fig. la, only seen from another point of view, illustrates a perspective view of a lubrication device according to another embodiment of the invention, fig. 2b illustrates schematically the same embodiment of the invention as shown in fig. 2a, as seen from above, fig. 3a illustrates a perspective view of a lubrication device according to yet another embodiment of the invention, fig. 3b illustrates a perspective view of the same embodiment of the invention as shown in fig. 3a, only seen from another point of view, and figs. 4a-4d illustrate schematically the main parts of a thread lubricator being a part of a lubricant distributor according to different embodiments of the invention.

Detailed description of the invention

Figs, la and lb illustrate perspective views of a lubrication device 1 according to an embodiment of the invention, as seen from two different points of view. This particular embodiment is adapted for lubrication of bolts 2 with a single thread 3, typically at one end of the bolt 2, and a bolt head 4 at the other end.

The bolt 2 is secured in its position in the lubrication device 1 by a number of wheels 5, 6 of which some are rotating wheels 5 for rotating the bolt 2, and some are rotatable securing wheels 6, whose main purpose is to secure the bolt 2 in the right position. At least some of the securing wheels 6 are mounted on a tilting arm 7, which can be tilted away from its working position, thus opening the assembly of rotating wheels 5 and securing wheels 6 for placing of the bolt 2 to be lubricated into the lubrication device 1 and for removing the bolt 2 from the lubrication device 1 again after the lubrication. Furthermore, the lubrication device 1 is equipped with a guide pin 22, which is used for controlling the longitudinal position of the bolt 2 to be lubricated, when placing the bolt 2 in the lubrication device 1.

The bolt 2 is rotated by means of a handle 8, which is connected to an axle 9 onto which at least some of the rotating wheels 5 are mounted. Rotation of the handle 8 also drives a pump 10, which is connected to the handle axle 9 by means of a belt drive 11. This pump 10 delivers the lubricant used for the lubrication of the bolt 2.

Due to the connection between the pump 10 and the handle 8 it is assured that the rate at which the pump 10 delivers the lubricant always matches the speed at which the bolt 2 is rotated, thus making the resulting amount of lubricant applied to the thread 3 independent of the rotational speed of the handle 8. The pump 10, which is typically a gear pump but could also be a pump of another type, can be geared in different ways to adjust the dosing of lubricant applied, depending on the type and size of the bolt 2 to be lubricated.

In other embodiments of the invention (not shown), the bolt 2 to be lubricated may be rotated by other means than rotating wheels 5, such as by means of a bracket gripping the head 4 of the bolt 3.

The illustrated lubricant source is a cartridge 12 filled with a lubricant in the form of a suitable lubrication paste or grease. The cartridge 12 is pressurised by means of pressurised air (not shown), for instance to a pressure of about 4 bar, in order to force the lubricant from the cartridge 12 through a pump conduit 13 towards the pump 10.

When the pump 10 is activated, lubricant is forced form the pump 10 through a distributor block conduit 14 towards a distributor block 15, from which the lubricant continues its motion towards the two lubricant distributors through two distributor conduits 16, respectively. This distributor block 15 is made adjustable in order to assure that the distribution of lubricant between the two lubricant distributors can be set correctly, depending on the type of bolt 2 to be lubricated.

The first lubricant distributor comprises a slider 17 holding a thread lubricator (not shown in this figure), which is arranged with a plurality of nozzles to inject the lubricant individually into a plurality of grooves of the thread 3 of the bolt 2, thus applying the lubricant to one or more surfaces in each groove of the thread 3. For a description of main parts of some embodiments of the thread lubricator, please refer to the descriptions relating to figs. 4a-4d here below. The thread lubricator is elastically suspended from the slider 17 in order to assure that it is correctly positioned in relation to the grooves of the thread 3 to be lubricated. Furthermore, the slider 17 is mounted on two sliding guides 18 for being adjustable in the longitudinal direction of the bolt 2, also during rotation of the bolt 2, in which the grooves of the thread 3, as seen from the thread lubricator, will move in the longitudinal direction of the bolt 2. This allows for adjusting the position of the thread lubricator depending on the length of the bolt 2 to be lubricated. The sliding guides 18 are mounted on the tilting arm 7 in order to avoid interference with the thread 3, when the bolt 2 to be lubricated is placed in the lubrication device 1.

The other lubricant distributor is a bolt head lubricator 19 comprising a nozzle arranged to apply lubricant to the underside of the bolt head 4. The bolt head lubricator 19 is spring-loaded in order to keep it in a position pressed firmly against the underside of the bolt head 4 at a constant pressure.

The bolt 2 is lubricated by placing it in the lubrication device 1 , making sure that the thread lubricator, which is held by the slider 17, and the bolt head lubricator 19 are properly positioned and in contact with the bolt thread 3 and bolt head 4,

respectively, and turning the handle 8 for one single rotation. During one rotation of the handle 8 and, thus, of the bolt 2, the full thread 3 and the full underside of the bolt head 4 will pass by the lubricant distributors. If the pump 10 and the distributor block 15 are both correctly adjusted and the lubricant distributors correctly positioned and in contact with the bolt thread 3 and the bolt head 4, respectively, a perfect and uniform lubrication of the relevant surfaces of the bolt 2 has been achieved. In other embodiments of the invention (not shown), the pump 10 and the rotation of the bolt 2 may be motor-driven and electronically controlled, for instance in a way so that one revolution of the bolt 2 is performed when a button is pressed. Fig. 2a and fig. 2b illustrate a perspective view and a schematic view as seen from above of a lubrication device 20 according to another embodiment of the invention. In this case, the lubrication device 20 is adapted for lubrication of a stud bolt 21 having a thread 3 in each end.

Basically, this embodiment is very similar to the one shown in figs, la and lb with the only exception that the bolt head lubricator has been replaced by a second thread lubricator held by a slider 17 mounted on a pair of sliding guides 18, just like the first thread lubricator. This means that the lubrication device 20 in the shown embodiment is able to lubricate the two threads 3 of the stud bolt 21 simultaneously.

Figs. 3a and 3b illustrate perspective views of a lubrication device 23 according to yet another embodiment of the invention, as seen from two different points of view. This particular embodiment is adapted for lubrication of the internal thread (not shown) of a nut 24.

Most of the parts of the lubrication device 23 shown in figs. 3a and 3b are similar to the parts of the two previously described embodiments 1 , 20 of the invention.

However, some elements are different due to the fact that it is an internal thread of a nut 24 that has to be lubricated rather than one or two external threads 3 of a bolt 2, 21.

The nut 24 is held by a nut holder 25, which is mounted on the same axle 9 as the handle 8 and is rotated by means of the handle 8. The shown embodiment of the lubrication device 23 comprises only a single lubricant distributor in the form of a nut thread lubricator. Like the thread lubricators of the previously described embodiments of the invention, the thread lubricator is mounted on a slider 17 on a pair of sliding guides 18 mounted on a tilting arm 7 and allowing the thread lubricator to move in a direction parallel to the axle 9. The main difference from the previously described embodiments of the invention is that the thread lubricator for lubricating the internal thread of the nut 24 is placed at the end of a lubricator conduit 26 extending into the nut 24.

Before lubrication, the nut 24 is placed in the nut holder 25, the tilting arm 7 is placed in a first position causing the thread lubricator to be placed near the rotational axis of the axle 9, and the slider 17 is moved towards the handle 8, causing the thread lubricator to enter the centre of the nut 24 without colliding with the thread. Finally, the tilting arm 7 is moved to a second position, in which the thread lubricator is in proper contact with the thread to be lubricated, and the lubrication can take place by turning the handle 8 for one full rotation. After the lubrication, the tilting arm 7 is moved back to its first position, the slider 17 is moved in the direction away from the handle 8, and the nut 24 can be removed from the nut holder 25.

Fig. 4a illustrates a top section plate 27 that can also be used as bottom section plate of a thread lubricator according to some embodiments of the invention. The top section plate is made from a very rigid material, such as for instance stainless steel. The dimensions of the top section plate 27 depend on the size of the thread 3 to be lubricated. In a typical application, the thickness may be 3 mm and the length of the top section plate 27 may be around 55 mm.

The rectangular top section plate 27 is equipped with a number of triangular "teeth" 28 along one of its long sides, these teeth 28 being dimensioned to fit exactly into the grooves of the thread 3 to be lubricated. The three through-holes 29 placed centrally and at each end of the plate 27 are used for mounting the thread lubricator to the lubrication device 1, 20, 23, while the remaining two through-holes 30 are used for feeding lubricant into the thread lubricator. When the plate 27 is used as bottom section plate, the lubricant feeding holes 30 are not used. Fig. 4b illustrates a lubricant chamber plate 31 to be placed just beneath the top section plate 27 in the thread lubricator. The lubricant chamber plate 31 , which may typically be made from the same material as the top section plate 27 in a thickness of about 0.5 mm, comprises teeth 28 along one long side and mounting holes 29 corresponding to the teeth 28 and mounting holes 29 of the top section plate 27. Furthermore, the lubricant chamber plate 31 comprises a lubricant chamber 32, which receives the lubricant through the two lubricant feeding holes 30 of the top section plate 27 and distributes it uniformly over the full length of the thread lubricator due to over-pressure created by the pump 10 in the distributor conduit 16 conducting the lubricant to the thread lubricator.

The nozzle plate 33, which is to be placed between the lubricant chamber plate 31 and the bottom section plate of the thread lubricator comprises teeth 28 and mounting holes 29 similar to the ones of the lubricant chamber plate 31. Furthermore, it comprises a number of lubricant nozzles in the form of slits 34 extending from the teethed side of the nozzle plate 33 far enough across the plate 33 to be in contact with the lubricant chamber 32 in the lubricant chamber plate 31 positioned just above the nozzle plate 33. The lubricant in the lubricant chamber 32 will be forced to leave the thread lubricator through these slits 34 between the teethed sides of the lubricant chamber plate 31 and the bottom section plate, respectively. Thus, the slits 34 will function as nozzles opening onto each of the two surfaces of each groove of the thread 3 to be lubricated. If only one of the surfaces in each groove of the thread 3 is to lubricated, another nozzle plate 33 with only one slit 34 per groove of the thread 3, as illustrated in fig. 4d, can be used instead.

The invention has been exemplified above with reference to specific examples of embodiments of the invention. However, it should be understood that the invention is not limited to the particular examples described above, but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims.

List of reference numbers

1. Lubrication device for bolt with single thread

2. Bolt with single thread

3. Bolt thread

4. Bolt head

5. Rotating wheel

6. Securing wheel

7. Tilting arm

8. Handle

9. Axle for rotation of workpiece

10. Pump

11. Belt drive

12. Lubricant cartridge

13. Pump conduit

14. Distributor block conduit

15. Distributor block

16. Distributor conduit

17. Slider for thread lubricator

18. Sliding guide

19. Bolt head lubricator

20. Lubrication device for stud bolt

21. Stud bolt

22. Guide pin

23. Lubrication device for threaded nut

24. Nut with internal thread

25. Nut holder

26. Lubricator conduit

27. Top/bottom section plate for thread lubricator

28. Triangular teeth

29. Through-hole for mounting of thread lubricator 30. Through-hole for feeding lubricant into thread lubricator

31. Lubricant chamber plate for thread lubricator

32. Lubricant chamber

33. Nozzle plate for thread lubricator

34. Slit (nozzle) in thread lubricator

Claims

1. A lubrication device (1) comprising a first lubricant distributor comprising a thread lubricator (27-34) arranged with a plurality of nozzles to inject a lubricant individually into a plurality of grooves of a first thread (3) of a workpiece (2, 21, 24), which is placed in the lubrication device for being lubricated, thus applying the lubricant to one or more surfaces in each groove of the thread, and a pump (10) for dosing the lubricant reaching the first lubricant distributor.

2. A lubrication device according to claim 1, further comprising means (5, 8, 9;

25) for rotating the workpiece around the rotational axis of the first thread.

3. A lubrication device according to claim 1 or 2, further comprising a second lubricant distributor (19).

4. A lubrication device according to claim 3, wherein the second lubricant

distributor comprises a nozzle arranged to apply a lubricant to a surface of the workpiece, such as the underside of a bolt head (4).

5. A lubrication device according to claim 3, wherein the second lubricant

distributor comprises a thread lubricator arranged with a plurality of nozzles to inject a lubricant individually into a plurality of grooves of a second thread (3) of the workpiece (21), thus applying the lubricant to one or more surfaces in each groove of the thread.

6. A lubrication device according to any of claims 3-5, further comprising a distributor block (15) for distributing the lubricant from the pump between the first lubricant distributor and the second lubricant distributor.

7. A lubrication device according to claim 6, wherein the distributor block is adjustable for obtaining different distributions of lubricant between the first lubricant distributor and the second lubricant distributor.

8. A lubrication device according to any of the preceding claim, wherein at least one lubrication distributor is elastically suspended or spring-loaded.

9. A lubrication device according to any of the preceding claim, wherein at least one thread lubricator is constructed from a number of plates (27, 31, 33) with different through-holes (29, 30, 32), stacked on top of each other and fixed tightly together.

10. A lubrication device according to any of claims 2-9, wherein the means for rotating the workpiece comprises a handle (8) for manual rotation of the workpiece.

11. A lubrication device according to any of claims 2-9, wherein the means for rotating the workpiece is driven by a motor and arranged to rotate the workpiece automatically at the initiation of a lubrication process, for instance when a button is pressed.

12. A lubrication device according to claim 11 , wherein the means for rotating the workpiece is arranged to rotate the workpiece for a single full rotation.

13. A lubrication device according to any of claims 2-12, wherein the pump is driven by the means for rotating the workpiece simultaneously with the rotation of the workpiece. A lubrication device according to any of the preceding claims, wherein the pump is a gear pump (10) that can be geared in different ways for obtaining different doses of lubricant reaching the lubricant distributor(s) during operation of the lubrication device.

A lubrication device according to any of the preceding claims, further comprising means for pressurising a lubricant source (12) for forcing lubricant from the lubricant source to the pump, for instance by means of pressurised air.