GB2037194A - Tools for use in exchanging bearing bushes in mountings - Google Patents

Abstract

Bearing bushes in mountings are exchanged by cutting away an annular lip of a first bush (2), to remove it, by a device comprising an annular cutter (17), a guide spindle (3) insertable through the bearing bush (2) and carrying the cutter (17) towards one end. The guide spindle (3) has a collar (4) on that end supporting an axially lockable bush (6) carrying a stop sleeve (22) for limiting the cut of the cutter (17) and having a shoulder (12) arranged to retain the cutter (17). An axially lockable support (27, 29) is threaded onto the guide spindle (3) towards its other end and axially adjusted by nuts (38, 39). A replacement bush (130) is inserted in the mounting and retained by peening its ends by a hand device having a casing block (110) with exchangeable inserts (120) carrying press dies (117) and counter elements (118) of the same size and a hydraulic actuating cylinder acting on the press die (117) through a two armed lever (116). <IMAGE>

Description

SPECIFICATION Atool for use in exchanging bearing bushes in mountings The invention relates to a tool for use in exchanging bearing bushes in mountings, more particularly in mounting members of aircraft. Such a tool, in one form may comprise a device for peening on new bearing bushes and in a second form may comprise a device for cutting away annular lips of peened in bearing bushes. The cut-away device therefore has a cutter carried by a guide spindle which may be inserted through the bearing bush and which also carries a stop element, an axially lockable support being screwable on to the other end of the guide spindle. The peening device is in turn provided with a press die which may be operated by an hydraulic actuating element which presses annular lips provided on the bearing bushes against the annular bevels provided at the ends of the receiving bores in the mountings.

Bearings of ball-and-socket joints are frequently locked in bores by having peened over annular lips provided on their end faces. The annular lips are thus pressed or peened against annular bevels provided at the ends of the receiving bores by appropriate tools, e.g. presses. Therefore it is necessary to cut away the peened over annular lips of these bearing bushes whenever they have to be exchanged.

However this is not always easy, particularly not if bearing bushes on aircraft mountings have to be exchanged.

In the past it has always been conventional to dismantle the mountings too and to cut out the peened over annular lips of the bearing bushes with the aid of a special cutting in a workshop. Forcing or pulling the relevant bearing bush out was then possible with the aid of a known pulling device.

Recently, however, there has been an increasing demand for bearing bushes which can be exchanged in aircraft mountings insitu. However, this requires a special tool for peening over the annular lips, which can be used even in inaccessible places. A known tool which is provided for the purpose of cutting off rivet like annular extensions of bearing bushes comprises a guide spindle which may be inserted through a bearing bush and a support sleeve resting against the mounting, in which a stop sleeve having a cutter may be screwed on to the guide spindle inserted through the bore.As already mentioned, this tool which has been provided for cutting off rivet like annular extensions, has the disadvantage that the force transmission for the rotary movement produced by manual displacement and necessary for cutting is effected via prestressed threaded nuts which ensure that the cutter is entrained. However if this measure is implemented there is relatively high wear on the threaded elements and thus these elements have to be replaced quite frequently.

In order to peen over the annular lips of new bearings bushes in mounting members, these lips are usually pressed against the annular bevels provided at the ends of the receiving bores with the aid of stamps of large presses. Peening bearing bushes in receiving bores is therefore always possible when the respective receiving members permit manipulation by means of a press. While this is of course quite easy in newly manufactured items it is difficult to exchange defective bearing bushes because the receiving members also have to be dismantled in order to do this.

In aircraft it is frequently necessary for safety reasons to exchange bearing bushes and thus also to dismantle the respective mountings. This dismantling is caused not by the need to remove the defective bearing bush and to put in a new bearing bush but rather by the peening operation. As mentioned previously, bearing bushes are peened over with the aid of presses because the force required for this is of the order of magnitude of some thousands of daN (decaNewtons). Although it is basically possible to dismantle defective bearing bushes and install new bearing bushes on installed mountings, the previously known techniques require dismantling of the mountings which is both expensive and time-consuming in order to peen over the newlyinserted bearing bush.

The invention seeks to provide a cut-away device and a peening device, for use in exchanging bearings in the receiving bores of mounting members such as those of the type stated at the outset, which devices enable the exchange of bearing bushes and, peening of them insitu on installed mountings.

According to a first aspect of the invention, there is provided a tool for use in exchanging bearing bushes in mountings comprising a device for cutting away the annular lips of peened over bearing bushes having a cutter, a guide spindle insetable through the bearing bush and carrying towards one end the cutter and a stop element for limiting the cut of the cutter and towards the other end an axially lockable support threaded on wherein the guide spindle has a collar on its cutter end supporting an axially lockable bush carrying the stop element and having a shoulder arranged to entrain the cutter.

Preferably the collar is provided with a recess for accommodation of a thrust bearing at the end of the guide spindle. The guide spindle of the cut-away device may have a collar at its end opposite the threaded bore, the collar having a shoulder constructed as a follower, for the cutter which may be placed on to the shoulder and axially locked and the collar may support an axially locked bush having an outer thread for the stop sleeve which has been screwed on and which may be adjusted thereby and with an annular recess for receiving a thrust bearing arranged on the end of the spindle.

The measure just mentioned does not apply load to the threaded elements by entrainment of the cutter during cut-away of an annular lip, so that the threaded elements only have to take up the force required for axial positioning of the individual elements. Thus entrainment of the cutter by means of a follower disc may take place with projections arranged on both sides and offset, in each case, by 90 , these projections engaging in corresponding recesses in the shoulder or the cutter. Thus a snap ring may be used to lock the exchangeable cutter on the guide spindle axially.

It is also advantageous if a threaded bush guided in the base of the support sleeve is provided for screwing on to the threaded part of the guide spindle, whereby a bearing collar provided on the threaded bush is inserted into a recess on the rear side of the base of the sleeve, which recess contains a needle bearing, and is axially locked. The threaded bush may be provided with a nut extension so that it may lock the support sleeve on the guide spindle with the aid of a lock nut.

According to a second aspect of the invention, there is provided a tool for use in exchanging bearing bushes in mountings comprising a device for peening the bearing bushes having a press die which is hydraulically operated for pressing annular lips on the bearing bush against annular bevels at bores for receiving the bearings wherein the device is constructed as a portable hand tool and comprises a casing block with exchangeable inserts for press dies and counter elements of the same size, the casing block having an actuating cylinder whose piston acts on the press die via a two armed lever.

The peening device provided in accordance with the invention may be capable of producing a force of up to 20,000 daN, and this is sufficient to peen over bearing bushes up to certain sizes. Thus the exchangeable inserts may comprise a U-shaped profiled block, the crosspiece of which has a projection on both sides, in each case, which engages into corresponding recesses of the casing block, the limb of the profiled block being provided with bores designed to receive the press die and the mating counter element. This measure provides the opportunity of matching the device to a bearing which is to be exchanged according to the requirements present in each case. The crosspieces of the U-shaped profiled blocks thus contain a threaded borehole into which a fixing screw may be screwed, this fixing screw projecting from the casing block.

Furthermore, it is advantageous if the piston of the actuating cylinder arranged in the casing block acts on the two-armed lever via an adjustable screw provided in the power arm for the purpose of adjusting the stroke and if the load arm of the two-armed lever mounted on the casing block is half the length of the power arm in order to achieve the desired operating force. As a result, on the one hand it is possible to achieve positive connection between the pressure stamp and the piston of the actuating cylinder through the two armed lever and the other hand to create the required free space for exchanging the inserts andlor pressure stamp and counter elements by screwing the adjustable screw into the two-armed lever.

The invention will now be described in greater detail, by way of example, with reference to the drawings, in which: Fig. 1 shows a section through a cutting-away device in accordance with the invention, Fig. 2 shows a front view of a peening over device in accordance with the invention; Fig. 3 shows a side view of the device according to Fig. 2, and Fig. 4 shows a portion of the peening over device according to Fig. 2 for a second operation.

Fig. 1 shows, in section, a device for cutting away a peened over annular lip, the said device being shown in use. The annular lip is in this case a part of a bearing bush 2 which is seated in a receiving bore of a mounting 1 and is to be exchanged. The device comprises a guide spindle 3 inserted through the bearing bush 2, which spindle has a collar4 and a flange 5 at one end. A bush 6 provided with an outer thread slides on the collar 4, the bush 6 having an extended portion 7 with an annular recess 8 on its side pointing towards the end ofthe guide spindle 3.

A bearing race 9 is inserted into this annular recess, which bearing race 9 forms a thrust bearing together with balls 10 and the flange 5. The bush 6 placed on to the collar4 of the guide spindle 3 is locked in known manner with respectto axial displacement with the aid of a spring ring 11 inserted into a groove.

Two opposite recesses 13 are provided in the shoulder 12 of the collar 4, into which two correspondingly positioned projections 15 of a follower disc 14 engage, this follower disc being pushed on to the guide spindle 3. On its other side the follower disc 14 has two further projections 16, offset with respect to projections 15 by 90 , and locking into corresponding recesses 18 of a cutter 17 which slides on the guide spindle 3. One sleeve-shaped cutter 17 is locked on the guide spindle 3 with the aid of a snap ring 20 with respect to axial displacements and engages with its cutting teeth 19 into an annular groove of the bearing bush 2 formed by its annular lips.The cutting angle of the cutting teeth 19 is 45" towards the outside and 30 towards the inside, this being in each case; related to the longitudinal axis of the guide spindle 3. A stop sleeve 22 is screwed on to the outer thread of the bush 6 and locked in position by means of a lock nut 23. This stop sleeve 22 has a plastics ring 24 on its end resting against the mounting 1 for the purpose of avoiding damage to the mounting 1.

On the other side of the mounting 1, a support sleeve 27 having a threaded bush 29 provided in the base of the sleeve is screwed over the guide spindle 3 which has a threaded shaft 26 at this end. Thus the support sleeve 27 is provided, at its ends abutting the mounting 1, with a plastics ring 30 in similar manner to the ring 24, in order to avoid damage to the mounting 1. The threaded bush 29 has a guide tube 32 which engages into a corresponding axial bore in the base 28 of the sleeve and is fixed therein by means of a spring ring 33 in known manner. At the rear side of the base 28 of the sleeve a recess 34 is provided in which is inserted a needle bearing 35 retained by means of a bearing collar 36 provided on the threaded bush 29. A spring ring 37 thus secures the elements inserted into the recess 34. The threaded bush 29 is provided with a nut like exten- sion 38 for the purpose of adjusting the device while the device may be locked in the adjusted position by a lock nut 39.

Cutting away of a peened over annular lip takes place in the following manner: in the first instance the guide spindle is positioned through the bearing bush until the cutter rests against the annular lip of the bearing bush. Then from the other side, the sup port sleeve having the threaded bush 29 is screwed on to the threaded shaft until the support sleeve 27 rests with its plastics ring 30 against the mounting 1.

By slightly tightening the threaded bush, a corresponding thrust is applied to the cutting teeth 19 of the cutter 17. After locking this adjustment with the aid of the lock nut 39, the guide spindle 3 may be rotated, for example with the aid of a screw wrench which may be applied to the hexagonal head 40 of the flange 5. Further thrust is achieved by releasing the lock nut 39, tightening the nut like extension 38 and re-tightening the lock nut 39. Cutting of the annular lip takes place until the stop sleeve 22 rests with its plastics ring 24 against the mounting 1 for the purpose of limiting the thrust. The stop sleeve 22 is preferably so adjusted on the bush 6 with the aid of the lock nut 23 that the annular lips are almost cut away; but in any case only to such an extent that the cutting teeth 19 do not engage the mountings.The small amount of residual material of the annular lips may be deformed easily when pressing out the bearing bush without restricting this process. The construction of the cutting device makes it possible to exchange the cutters for the purpose of regrinding andlorforcutting bearing bushes of a different size.

However it is necessary to reset the stop sleeve on the bush 6 in order to prevent engagement of the cutting teeth with the respective mounting when cutting away the annular lip. The thrust bearings on both sides of the device reduce the resultant friction so that the force to be applied during the cutting process depends to a large extent on the thrust which has been set.

The nut like extension and the lock nut may be provided with corresponding levers or may have wings in order to set or adjust the thrust easily and rapidly.

The peening over device comprises a casing block 110 to which a hydraulic adjusting cylinder 111 is fixed by means of a fixing clip 112 and corresponding screws 113. The piston 114 of the hydraulic adjusting cylinder 111 abuts an adjustable screw 115 on the power arm of a two-armed lever 116, the load arm of which lever, which is half as long as the power arm, pressing against a press die 117. The two-armed lever 116 is mounted in known manner in the casing block 110. By use of the two-armed lever, the device may be kept small since the lever, because of its ratio, results in doubling of the force produced by the hydraulic adjusting element. Press die 117 is inserted into a corresponding bore of a U-shaped profile block 120 i.e. in one limb of this profiled block.A counter element is inserted into a corresponding bore in the second limb of the U-shaped profiled block, which counter element is in alignment with the press die. The profiled block 120 has a projecting projection 121 on both sides of its crosspiece, these projections 121 engaging in corresponding bores 119 in the casing block. As a result, an appropriate support for peening over is provided.

Moreover, a threaded bore is provided in the crosspiece of the U-shaped profiled block 120 into which a fixing screw 122, provided on the casing block 110, may be screwed for fixing purposes.

The U-shaped profiled blocks 120, which may be exchanged for the purpose of matching them to different bearings, contain a centering pin 125. This centering pin 125 is inserted into a corresponding bore in the counter element 118 through a bore 126 of the profiled block 120 and engages into the bore of the bearing 130 which is to be peened over. As may be seen from Fig. 2, the bearing bush 130 is peened over in an aperture 131 of mounting 132 which is installed in an aircraft. The bearing bush 130 is therefore provided with annular lips 133 at both end faces while, in each case, one annular lip is peened over in one operation.

Fig. 2 shows the first operation in which the lefthand annular lip is peened over by the press die 117.

The press die 117 is selected in accordance with the size of the bearing 130 and is provided with a conical end face. The counter element 118 has a set back flat end face which thus can abut both the bearing 130 and the aperture 131 of the mounting 132. Hydraulic fluid is supplied to the hydraulic actuating cylinder 111 for peening over the annular lips and is in fact supplied via a pressure line 140 having a quickacting coupling 141. The hydraulic fluid may be taken from a supply system; however it is also poss ibleto produce the system pressureforthe hydraulic actuating element using a hand pump. In the latter case it is possible to calibrate the pressure-indicating device ofthe hydraulic hand pump not in pressure but rather in power and in fact in the power of the force arising during peening.It is advisable to allow the hydraulic pressure and thus the force produced on the respective annular lip to act for a certain period of time, preferably 15 to 20 sec, in order to achieve a reliable peening action.

After carrying out peening over of one annular lip in a first operation it is necessary to exchange the counter element 118 in order to peen over the annular lip at the other side of the bearing. Fig. 4 shows a portion of the device in which the counter element 118 is replaced by a counter element 134. This counter element 134 has a construction similar to the press die 117 whereby safe abutment of this counter element for peening the second annular lip is possible. The press die 117 remains the same as in the first operation. The process of peening is carried out in the same way as in the first operation.

As already mentioned, it is possible to exchange the U-shaped profiled blocks 120, in the form of inserts, for peening over bearings of different size.

The fixing screw 122 is released for this purpose and the insert may be removed. In the case of this type of exchange, it is necessary to release the adjusting screw 115 on the two-armed lever in order to achieve the required free space for this operation. However, it is necessary to screw the adjusting screw in completely in order to exchange the press die and the counter element for carrying out different operations in orderto be able to remove these components from the fitted bore of the U-shaped profiled blocks.

The adjusting screw 115 also makes it possible to achieve positive connection between the piston of the actuating cylinder and the press die through the two-armed lever without any play between them.

The quick-acting coupling 141 on the pressure line 140 makes it possible to separate or connect the pressure line easily and in this way facilitates sensible operation. In the actuating cylinder, a resetting spring (not shown) is provided which ensures return of the piston in each case after an operation has taken place.

Both the resetting spring and the quick-acting coupling which are provided with sealing elements prevent air from penetrating into the adjusting cylinder and therefore ensure a perfect mode of operation. The above described device is distinguished by the fact that it facilitates peening of bearing bushes in inaccessible mountings.

Claims (18)

1. Atool for use in exchanging bearing bushes in mountings comprising a device for cutting away the annular lips of peened over bearing bushes having a cutter, a guide spindle insertable through the bearing bush and carrying towards one end the cutter and a stop element for limiting the cut of the cutter towards the other end and an axially lockable support threaded on wherein the guide spindle has a collar on its cutter end supporting an axially lockable bush carrying the stop element and having a shoulder arranged to entrain the cutter.

2. A tool according to claim 1, wherein the collar is provided with a recess for accommodation of a thrust bearing at the end of the guide spindle.

3. A tool according to claim 1 or 2, wherein entrainment of the cutter device takes place via a cross-shaped driving disc having projections which are arranged on both sides and in each case offset by 90 , which projections engage into corresponding recesses of the shoulder of the collar or of the cutter.

4. Atool according to claim 1,2 or 3 wherein the cutter is locked with respect to axial displacement by means of a snap ring which is located in a groove in the guide spindle.

5. A tool according to any one of claims 1 to 4, wherein the cutting teeth of the cutter which is in the form of a sleeve have a cutting angle of 45" for the outer cutting blade and 30 for the inner cutting blade with respect in each case, to the axis of rotation.

6. A tool according to any one of claims 1 to 5, wherein the support comprises a sleeve with a threaded bush guided within the base of the sleeve, which bush being designed to be screwed on to the threaded end of the guide spindle; and wherein a bearing collar is provided on the threaded bush and is inserted and axially locked in a recess on the rear side of the base of the sleeve, this recess containing a needle bearing.

7. Atool according to claim 6, wherein the threaded bush has a nut like extension and a lock nut which may be screwed against the nut extension is provided for the purpose of locking the support sleeve on the guide spindle.

8. Atool for use in exchanging bearing bushes in mountings comprising a device for peening the bearing bushes having a press die which is hydraulically operated for pressing annular lips on the bearing bush against annular bevels at bores for receiving the bearings wherein the device is constructed as a portable hand tool and comprises a casing block with exchangeable inserts for press dies and counter elements of the same size, the casing block having an actuating cylinder whose piston acts on the press die via a two armed lever.

9. A tool according to claim 8, wherein the exchangeable inserts comprise a U-shaped profile block, the crosspiece of which has a projection on both sides which engages into corresponding reces sesofthecasing block and the limbs of which are provided with corresponding bores for receiving the press die and the counter element.

10. A tool according to claim 9, wherein the crosspiece of the U-shaped profiled block has a threaded borehole into which a fixing screw may be screwed, the fixing screw projecting out of the casing block.

11. Atool according to claim 9 or 10 wherein the piston of the actuating cylinder arranged in the casing block acts on the two-armed lever via an adjustable screw provided for the purpose of adjusting the stroke of the power arm of the lever, and the load arm of the two-armed lever is half the length of the power arm so as to achieve the desired operating force for the press die.

12. Atool according to any one of claims 9 to 11, wherein the counter element inserted into the bore of the U-shaped profiled block has a bore with a longitudinally displaceable centring pin which may be used for the purpose of aligning the peening device.

13. Atool according to any one of claims 9 to 12, wherein two counter elements are provided exchangeably for first and second operations are differently constructed at their end faces, the end face of the counter elementforthe first opseration having a setback flat shape abutting the end face of the bearing bush and the mounting and the end face of the counter element for the second operation has a conical shape abutting the peened over annular lip.

14. Atool according to any one of claims 9 to 13, wherein the actuating cylinder in the casing block contains a resetting spring for the piston.

15. Atool according to any one of claims 9 to 14, wherein the actuating cylinder is supplied with hdraulic fluid via a pressure line which contains a quick-acting coupling arranged directly at the casing block having sealing elements for carrying out rapid separation and/orconnection.

16. Atool for use in exchanging bearing bushes in mountings substantially as described herein with reference to Figure 1 of the drawings.

17. Atool for use in exchanging bearing bushes in mountings substantially as described herein with reference to Figures 2 to 4 of the drawings.

18. Atool for use in exchanging bearing bushes in mountings comprising a tool according to any one of claims 1 to 7 and 16 combined with a tool according to any one of claims 8 to 15 and 17.