GB2222973A - Drive apparatus for a nut and threaded member - Google Patents

Abstract

The apparatus comprises a socket 6 receiving a nut 3 and an end portion of a threaded member 2 onto which the nut 3 is screwed, the socket comprising two co-axial parts 7, 8, each having an internal profile corresponding to the external profile of nut, and being relatively rotatable between first and second positions about their common axis 9 over a prescribed arc, the first position driving the threaded member 2 with the two parts 7, 8 in a misaligned condition in which the inner part 7 is partly closed-off by the outer part 8 whereby the nut is captivated within the inner part, and the second position being a nut running position in which the two parts are aligned, and in which the nut is no longer captivated but is free upon rotation of the apparatus to run along the threaded member 2 to effect tensioning thereof. <IMAGE>

Description

DRIVE APPARATUS FOR A NUT AND THREADED MEMBER This invention relates to a drive apparatus for use in driving a nut and also a threaded member, such as a roof bolt into a mine roof for strata control purposes, or a stud into a component such as the engine block of an internal combustion engine for retaining the cylinder head.

In roof bolting operations using a portable, handoperated and extensible drilling leg which is hydraulically or pneumatically powered, the leg is seated at one end on a mine floor and at the other end is provided with a drive head serving - after receiving a drill rod and drilling a bolt hole to the desired depth - to receive and rotate, and simultaneously axially advance, a steel roof bolt into the hole, with a frangible container(s) of curable resin within the hole ruptured by an inner end of the bolt, and with an outer end of the bolt projecting slightly from the hole and being externally threaded to receive a nut, with a washer interposed between the nut to bear against the mine roof.

Ideally, the bolt should be pr e-te n si o ne d by the nut for optimum effectiveness against the propogation of fissures and hence roof instability but principally due to the torque limits deliberately in-built for safety purposes into portable drilling legs, it is not usually possible to apply sufficient torque to the nut to induce any effective tension in the bolt.

As an alternative, special arrangements, such as deformed threads, nuts with synthetic inserts etc., have been adopted on a limited scale but these arrangements introduce other disadvantages.

The drive apparatus in accordance with the invention enables a roof bolt with a standard thread and a standard nut to be not only driven into the hole but also tensioned.

Likewise, with engine blocks, the standard technique, after drilling and tapping a stud-receiving hole is to screw in the stud, then to fit the cylinder head over the studs and then to screw the clamping nuts or to projecting, threaded ends of the studs.

The drive apparatus of the invention enables the studs and nuts to be applied in a single operation after location of the cylinder head on the block, and tightened.

It will be appreciated that the driving apparatus of the invention is equally effective in any analogous application where it is required to secure a second component to a first component by the use of a bolt(s) or stud(s) anchored by some means at one end in the first location or component and having its other end threaded and adapted to pass through an aligned hole in the second component to receive a clamping/tensioning nut.

According to the present invention, there is provided a drive apparatus for a nut and a threaded member on which the nut is screwed, the apparatus having at one end a drive member adapted, in use, to be drivably connected to a powered drive device to convey torque to the apparatus and having a socket extending axially inwardly from the other, terminal end, and adapted to receive a nut and an end portion of the threaded member onto which end portion the nut is screwed, the socket comprising two co-axial parts, one being an axially inner part remote from the terminal end and the other being an axially outer part adjacent the terminal end, with a socket base located inwardly of the inner part which is of axial length such that the nut is receivable wholly within the inner part, and each part having an internal profile corresponding to the external profile of a nut to be driven by the apparatus, the two parts being mutually rotatable between first and second positions, about their common axis and over a prescribed arc upon exceeding a predetermined release setting of a release mechanism between the two parts, the first position, being a driving position for the threaded member, when the nut is engageable in the inner part only, with the two parts in a misaliged condition in which the internal profile of the inner part is partly closed-off by the unaligned outer part whereby the nut is captivated within the inner part of the socket, and the second position being a nut running position in which the two parts are in an aligned condition, in which the nut is no longer captivated but is free upon rotation of the apparatus to run along the threaded member to effect clamping and/or tensioning of the threaded member.

Mutual rotation of the two parts to change between the aligned and non-aligned conditions and hence to change the driving mode may be effected manually and/or automatically.

Basically, at the start of operations, the two parts are rotated e.g. manually, to their aligned condition so that a nut, already screwed onto the end portion of a threaded member, may be passed into the socket, to be located wholly within the inner part and hence to be clear of the outer part, so that mutual rotation may then be effected, e.g. manually, to change to the non-aligned mode, whereby the outer part blocks the extraction of the nut from the socket, and consequently the nut is captivated. The drive device is then activated for simultaneous linear advance and rotation not only of the apparatus but of the threaded member to advance the latter the desired axial distance, the end of the threaded member almost immediately striking the socket base so that the threaded member jams in the socket to allow torque to be applied frictionally to the threaded member.When driving of the threaded member has been completed mutual rotation between the two parts is again effected, e.g. automatically, to align the two parts, with continued application of at least rotational drive power effecting nut running and hence clamping and/or tensioning of the threaded member.

The drive member is of a form and profile to suit the powered drive device with which it is to be associated, in use. Thus, if the powered drive device w-ere to be an internally hexagonal socket or chuck, then the drive member would be a spindle of hexagonal section. Conversely, the powered drive device could constitute the male driving member and the drive member a female driving recess.

It will be appreciated that if the nut is hexagonal, this will be the internal profile of the inner and outer parts. In this case the extent of inner to outer part rotation would conveniently be 300. For square nuts, mutual rotation over an arc of 450 is of course required.

The release mechanism may in principle be any standard engineering release mechanism e.g. a spring loaded ball/ball catch adapted to engage a suitable aperture. In detail, three spring loaded ball catches, 1200 apart may be employed.

Although the release mechanism may be actuable rotationally, e.g. upon a torque setting being exceeded, in an alternative arrangement the release mechanism is actuable axially, e.g.

upon the terminal end striking, directly or indirectly, an abutment such as a mine roof.

Automatic release of the release mechanism may be readily provided by suitable setting of the release mechanism, e.g. with a rotationally actuable release mechanism operating at approximately 25 lbf torque.

The inner and outer parts are preferably mutually engageable, by the outer part having a circular section recess to receive the inner part as a rotational fit. The arc of rotation is conveniently provided by machining at least one slot of appropriate arcuate length, e.g. 350, in one part to be slidably engaged by a radially extending pin of the other member, with the apparatus being in one drive mode when the pin(s) is at one end of the slot(s), and in the other drive mode when the pin(s) is at the other end of the slot(s).

The inner part may be formed integrally with both the socket base and the drive member, with the outer part being generally sleeve-like surrounding the inner part, and providing at least a portion of the terminal end. The outer part is preferably provided with two diametral slots, so that a radially extending pin, of length corresponding to the external diameter of the outer part, may be passed through one of the slots and pressed into a diametrically extending through hole of the inner part, so that opposite ends of the pin are located in opposite slots and the pin also serves to retain together the inner and outer parts. Loss of the pin may be prevented by an axially extending screw passing through a threaded hole in the socket base to engage the pin.

In a first embodiment, a rotationally actuable release mechanism may be employed, comprising at least one blind radial bore in the inner part housing a compression spring operable on a ball projecting partially from the blind bore into an aligned aperture of the outer part. Penetration of the ball, and hence the torque release setting, may be controlled by an adjustable screw provided in a tapped radial hole in the outer part, with one end of the screw engageable with the opposite side of the ball to that engaged by its compression spring. Muliple numbers of such a release mechanism, e.g. at 1800 or 1200 locations, may be provided if required.

In a second embodiment, an axially actuable release mechanism may be employed, with a sleeve of the mechanism surrounding the outer part and being axially slidable, within limits, with respect to the outer part, the sleeve having an internal, circumferential groove, while the outer part may be provided with two, axially spaced sets of ball receiving apertures for a first set of ball catches and a second set of spring-loaded ball catches, with the geometry being such that upon a certain axial loading on the sleeve, the spring loading is overcome or released, to change the drive mode of the apparatus.

Clearly, the axial length of the outer socket part should be such that, in the aligned, nut-running mode as the nut is progressing axially out of the axially stationary socket upon rotation of the latter, sufficient tension is applicable to the bolt before the nut exits the socket.

However, despite the length of the outer socket part, it may not be possible to attain sufficient tension for instance in the application of roof bolts where poor roof conditions are encountered and accordingly, in accordance with a second embodiment the apparatus is extensible, within limits, so that in the nut running mode, the outer part (which is rotating the nut) follows the nut axially along the threaded member and is axially displaceable with respect to the inner part. In detail, the inner part may be hollow and slidably receives a drive spindle e.g. of hexagonal section, one end of which provides the socket base and the other end of which conveniently projects from the apparatus and constitutes the drive member, with the drive spindle being axially movable into the inner part against the action of a coil compression spring.The drive spindle is preferably provided, intermediate its ends, with three longitudinally extending slots located 1200 apart, which slots at their outer ends remote from the socket base run into a circumferential recess, the slots being slidably engaged by the ends of three radially extending pins, also located 1200 apart, secured in tapped holes in the outer part and passing through arcuate slots e.g.

extending over an arc of 350, in side walls of the inner part.

In detail, the drive spindle is initially in its retracted position, and the two parts are aligned to permit insertion into the socket of a nut already screwed onto the end of its associated threaded member, after which rotation is effected, e.g. manually, to effect misalignment of the two parts to captivate the nut, and the drive spindle is pushed into the inner part, against the action of the compression spring. Power is then applied to the spindle to advance the bolt into the bolt hole.When the spindle reaches its maximum advanced position the three pins leave the circumferential recess, enter their respective longitudinal slots and progressively move to the opposite ends of their respective arcuate slots, thereby aligning the two parts and changing the apparatus to the nut running mode, with the drive continued and the inner and outer body parts, whilst still rotating, moving axially along the hexagonal drive spindle under the influence of the coil compression spring, at a rate matching the axial progress of the nut along the threaded member, until the desired torque has been applied to the nut.

The desired torque may be set automatically by suitable adjustment, or limitation, of the torque available from the powered drive device.

Automatic mode switching may be effected by the terminal end striking an abutment surface thereby momentarily halting its rotation and/or applying an axial loading on the apparatus for either a rotational release mechanism or an axial release mechanism. For mining applications, the mine roof may constitute the abutment surface and the terminal end may be provided with projecting teeth or other means whereby upon striking the mine roof which constitute the abutment surface, (and for apparatus having a rotational release mechanism) rotation of the outer body part is halted while the continued application of torque from the drilling leg rotates the pins through 350 to change to the nut running mode. For other applications such as with a cylinder head, a knurled outer face may provide sufficient friction.

Instead of relying upon the terminal face contacting an abutment surface, a catch system may be provided to effect automatically mutual rotation of the two parts and hence the changeover between the two driving modes.

It may be that, in certain circumstances, the available driving torque in the nut running mode and the thread angle are such that nut running is resisted in which case it is preferred to provide a chamfer on one part, e.g. on the lower edges of the hexagon faces of the outer part if the nut is hexagonal.

The invention will now be further described, by way of examples, with reference to the accompanying drawings, in which: Figure 1 is an axial sectional view through a first embodiment of apparatus in accordance with the invention, in a nut-captivated position; Figure 2 corresponds to Figure 1 but shows the apparatus in its non-captivated position; Figures 3 and 4 are respectively a side elevation and a plan view of the inner part of the appartus of Figures 1 and 2; Figures 5, 6 and 7 are respectively a top plan, a side elevation, and an underneath plan of the outer part of the appartus of Figures 1 and 2; Figures 8 and 9 correspond respectively to Figures 1 and 2 but show a second embodiment; Figures l and 11 are respectively a side elevation and a plan view of the inner part of the second embodiment;; Figures 12 and 13 are respectively an axial sectional view and a plan view of the outer part of the second embodiment; Figures 14 and 15 are respectively an axial sectional view and a plan view of the sleeve of the second embodiment; and Figures 16 to 18 show a third and telescopic embodiment of apparatus in three different operational positions.

In all three embodiments, like components are accorded like reference numerals.

In the drawings, a drive apparatus 1 is intended to drive firstly a threaded member 2, e.g. into a bore hole in a rock formation, and secondly, a nut 3 screwed to the threaded member 2.

The apparatus 1 is provided at one end with a drive member 4 in the form of a hexagonal sectional spigot adapted to be received in a suitable chuck etc., of a powered drive device, such as a mine roof bolting machine capable of imparting both rotary and linear motion to the apparatus l, the other, terminal end 5 of which has a socket 6 extending axially inwardly therefrom, the socket 6 being adapted to receive the nut 3 and an end portion of the threaded member 2 onto which the nut 3 is screwed.

The socket 6 comprises an inner part 7 remote from the terminal end 5, and a co-axial outer part 8 adjacent the terminal end 5, the axis being indicated at 9. The inner part 7 has a socket base 18 and is of such axial length that the nut 3 is receivable wholly within the inner part 7. As the nut 3 has an industry-standard hexagonal periphery, the inner and outer part 7 and 8 each have a complementary internal hexagonal profile comprising flats 11 and corners 12.

The outer part 8 has a circular section recess 13 to receive the inner part 7 as a rotational fit, and is provided with two diametrically opposite slots 14 subtending an angle of 300.

The inner part 7 is provided with diametrically extending through hole 15 intersected by an axial tapped hole 16 in the socket base 18. A pin 17 of length approximating to the external diameter of the outer part 8 is passed into the hole 15, with ends of the pin located in the slots 14. The pin 17 serves firstly to prevent axial separation of the inner and outer parts 7 and 8, and is itself prevented from loss by a screw 18 screwed into the tapped hole 16 and engaging the pin 17 either frictionally or positively by passing into a neck 19 (see Figures 8 and 9) of the pin 17. The latter serves secondly as a sliding guide along the slots 14, with the pin presence at opposite ends of the slotb defining the positions of the inner and outer parts 7 and 8 about the axis 9 in the first position (Figures 1 and 8) and the second position (Figures 2 and 9).

A release mechanism 2 between the inner and outer parts 7 and 8 comprises a ball catch constituted by a blind radial bore 21 in the inner part 7, in which bore is located a compression spring 22 urging a ball 23 from the bore and into engagement with a cut-like aperture 24 in the outer part 8.

The latter is also provided with a tapped hole 25 containing an adjustment screw 26, one end of which engages the opposite side of the ball 23 from that engaged by the spring 22, to vary the torque at which the ball catch will release, to permit mutual rotation of the two parts 7 and 8 to the second position, in which the flats 11 of both the inner and outer parts 7 and 8 are aligned, whereby the nut 3 is no longer captivated.

Thus, in the first position - being the driving position for the threaded member 2 - the parts 7 and 8 are misaligned so that a previously inserted nut 3 is captivated within the inner part, by the outer part being manually rotated through 350 so that the flats 11 of the outer part bridge the corners 12 of the inner part.Changeover to the second position can either be manual, after halting the powered drive device, or automatic by the terminal end 5 striking the rock face adjacent a bore hole-in which the threaded member 2 is to be fastened, or striking a cylinder head, and being momentary halted, the sharp increase torque overcoming the resistance to rotation provided by the ball catch(es), to permit mutual rotation through 350 to align the flats 11 of the inner and outer parts 7 and 8, so that with continued rotation of the appartus 1, the nut 3 is now free to move along the threaded member 2, eventually exiting from the outer part 8.

Whereas the first embodiment embodies a rotationally actuable release mechanism, the second embodiment shown in Figures 8 to 16, incorporates an axially actuable release mechanism, again of the ball catch form. It will be seen from Figures 8 to 11, that the outer part 8 is surrounded by a sleeve 27 having an internal, circumferential groove 28, and above this groove a circumferential surface 29. A knurled gripping surface 3 is provided externally of the sleeve 27.

The outer part 8 is modified by the inclusion of two axially spaced sets of ball receiving apertures, being a first set of three blind radial holes 31 located 1200 apart to receive spring-loaded balls to co-operate with the groove 28, and a second set of two apertures 32 located 1800 apart to receive balls which are not spring-loaded to co-operate with two concave indentations 33 in the outer periphery of the inner part 7 located at 1800 spaced locations. Furthermore, the outer part 8 is provided with diametrically opposite, axially extending slots 34 to each to receive a retaining pin attached to the outer part 8, whereby the sleeve 27 is slidably captivated to the apparatus 1.

With this embodiment, with the flats 11 of the inner and outer parts 7 and 8 aligned, and with the spring-loaded balls engaging the surface 29, a nut 3 and the end of the threaded member 2 onto which the nut is screwed is inserted into the apparatus, and specifically the nut 3 is located wholly within the hexagonal profile of the inner part 7. The two parts are then mutually rotated, by hand, through 350, so that the nut 2 becomes captivated by the flats 11 of the outer part 8 bridging the corners 12 of the inner part 7 and the two balls engage the indentations 33.The sleeve 27 is then axially advanced so that the pins are located at the bottoms of the axial slots 34, and the surface 29 moves beyond the spring-loaded balls until the groove 28 is presented to the spring-loaded balls, their engagement of the groove 28 thus latching the parts 7 and 8 in their non-aligned position until the terminal end of the apparatus, which end in this embodiment is constituted by the terminal end of the sleeve 27, strikes the rock face adjacent a bore hole, or a cylinder head, such that the axial loading on the sleeve 27 overcomes the latching effect of the spring catches, to displace the sleeve 27 to retract the spring-loaded balls from the groove 28 and to bring them back into engagement with the surface 29 so that, when'the sleeve 27 is fully displaced, the pins engage the upper ends of the slots 34, so that upon continued rotation of the apparatus, the pin 17 may be rotated to the other end of the slots 14, to bring about alignment of the flats 11 of the inner and outer parts 7, 8, thereby attaining the second, nut-running position.

In the third embodiment, the part 7 is hollow and slidably receives a drive spindle 35 of hexagonal section One end of the drive spindle 35 provides the socket base 10, while the other end projects from the apparatus 1 and provides the drive member 4. The drive spindle 35 is axially movable into the inner part 7 against the action of a coil compression spring 36. Externally, the drive spindle 35 is provided, intermediate its ends, with three longitudinal slots 38 located 1200 apart which, at their outer ends remote from the socket base 18, run into a circumferential groove 39. Each slot 38 is slidably engaged by an end of a pin 4 secured in a tapped hole 41 in the outer part 8 and having a lock nut 42, and passing through an arcuate slot 43, subtending 350, in the inner part.

In use, the telescopic effect is achieved by the pins 4 progressively moving up their respective slots 38, under the influence of the coil compression spring 36. Also indicated in Figures 16 and 18 is a bore hole 44 at the inner end of which is a frangible resin bag 45, while the threaded member 2 is also provided with a washer 46 on which the nut 3 is adapted to bear to tension the member 2.

Finally, as indicated in various drawings of the three embodiments, a chamfer 43 is preferably provided on the lower edges of the hexagon faces or flats 11.

Claims (25)

1. A drive apparatus for a nut and a threaded member on which the nut is screwed, the apparatus having at one end a drive member adapted, in use, to be dr iv ably connected to a powered drive device to convey torque to the apparatus and having a socket extending axially inwardly from the other, terminal end, and adapted to receive a nut and an end portion of the threaded member onto which end portion the nut is screwed, the socket comprising two co-axial parts, one being an axially inner part remote from the terminal end and the other being an axially outer part adjacent the terminal end, with a socket base located inwardly of the inner part which is of axial length such that the nut is receivable wholly within the inner part, and each part having an internal profile corresponding to the external profile of a nut to be driven by the apparatus, the two parts being mutually rotatable between first and second positions, about their common axis and over a prescribed arc upon exceeding a predetermined release setting of a release mechanism between the two parts, the first position, being a driving position for the threaded member, when the nut is engageable in the inner part only, with the two parts in a misaliged condition in which the internal profile of the inner part is partly closed-off by the unaligned outer part whereby the nut is captivated within the inner part of the socket, and the second position being a nut running position in which the two parts are in an aligned condition, in which the nut is no longer captivated but is free upon rotation of the apparatus to run along the threaded member to effect clamping and/or tensioning of the threaded member.

2. An apparatus as claimed in Claim 1, wherein the drive member is a spindle or spigot of hexagonal section.

3. An apparatus as claimed in Claim 1 and Claim 2, wherein the internal profile of the inner and outer parts is hexagonal.

4. An apparatus as claimed in any preceding Claim, wherein the release mechanism comprises a spring-loaded ball/ball catch adapted to engage a suitable aperture.

5. An apparatus as claimed in Claim 4, wherein three spring-loaded ball catches are employed, located 128o apart.

6. An apparatus as claimed in any preceding Claim, wherein the release mechanism is actuable rotationally.

7. An apparatus as claimed in any one of Claims 1 to 5, wherein the release mechanism is actuable axially.

8. An apparatus as claimed in any preceding Claim, wherein the inner and outer parts are mutually engageable by the outer part having a circular section recess to receive the inner part as a rotational fit.

9. An apparatus as claimed in Claim 8, wherein an arc of rotation is provided by machining at least one slot of appropriate arcuate length in one part to be slidably engaged by a radially extending pin of the other part.

1. An apparatus as claimed in Claim 8 or Claim 9, wherein the inner part is formed integrally with both the socket base and the drive member.

11. An apparatus as claimed in any one of Claims 8 to 1, wherein the outer part is generally sleeve like, surrounding the inner part and providing at least a portion of the terminal end.

12. An apparatus as claimed in Claim 11, wherein the outer part is provided with two diametral slots, so that a radially extending pin, of length corresponding to the external diameter of the outer part passed through one of the slots and into a diametrically extending through hole of the inner part, with opposite ends of the pins located in opposite slots, serves to retain together the inner and outer parts.

13. An apparatus as claimed in Claim 12, wherein a axially extending screw, passing through a threaded hole in the socket base, engages the pin.

14. An apparatus as claimed in any preceding Claim, wherein a rotationally actuable release mechanism is employed.

15. An apparatus as claimed in Claim 14, wherein the release mechanism comprises at least one blind radial bore in the inner part housing a compression spring operable on a ball projecting partially from the blind bore into an aligned aperture or recess of the outer part.

16. An apparatus as claimed in Claim 15, wherein penetration of the ball is controlled by an adjustable screw provided in a tapped radial hole in the outer part.

17. An apparatus as claimed in any one of Claims 1 to 13, comprising an axially actuable release mechanism.

18. An apparatus as claimed in Claim 17, wherein the release mechanism comprises a sleeve surrounding the outer part and being axially slideable, within limits, with respect to the outer part, the sleeve having an internal, circumferential groove, while the outer part is provided with two, axially spaced sets of ball receiving apertures for a first set of ball catches and a second set of spring-loaded ball catches, with the geometry being such, that upon a certain axial loading of the sleeve, the spring loading is overcome or released, to change the drive mode of the appartus.

19. An apparatus as claimed in any preceding Claim, of an extensible or telescopic kind.

2. An apparatus as claimed in Claim 19, wherein the inner part is hollow and slidably receives a drive spindle, one end of which provides the socket base and the other end of which constitutes the drive member, the drive spindle being axially movable into the inner part against the action of a coil compression spring.

21. An apparatus as claimed in Claim 2, comprising drive means between the drive spindle and the inner part in the form of three longitudinal slots, spaced 1200 apart, which slots at their ends remote from the socket base run into a circumferential recess, and each slot being slidably engaged by the end of a radially extending pin secured in a tapped hole in the outer part and passing through an arcuate slot in the inner part.

22. An apparatus as claimed in any preceding Claim, wherein the internal profile of one part is provided with a chamfer.

23. An drive apparatus substantially as hereinbefore described with reference to Figures 1 to 7 of the accompanying drawings.

24. A drive apparatus substantially as hereinbefore described with reference to Figures 8 to 15 of the accompanying draw ings.

25. A drive apparatus substantially as hereinbefore described with reference to Figures 16 to 18 of the accompanying drawings.