Patent Grant
11440168
The present invention relates to the field of backup wrenches.
A non-limiting application of the present invention provides a backup wrench arrangement for limiting the rotation of one or multiple fastener elements, for example to facilitate the checking, tightening and/or loosening of arrangements of nuts and bolts on bolted joints such as those found on pressure boundary bolted joints.
When tightening, loosening and/or checking the tightening torque on a bolted joint, it is known to use a backup wrench as disclosed for example in U.S. Pat. No. 1,431,832. The backup wrench is placed on a nut or a bolt head on a first side of the bolted joint and the lever portion of the backup wrench rests against the head of another bolt to prevent rotation of the wrench and therefore the nut or bolt head on which it is placed. An operator can then apply a tightening torque to the opposite end of the bolt on the second side of the bolted joint, the tightening torque being partially reacted by the backup wrench without needing an additional operator on the first side of the bolted joint. There are however a number of issues with such labour saving devices such as rotation in one direction only is resisted, unless the backup wrench rotates until the lever portion contacts the head of another adjacent bolt.
U.S. Pat. No. 5,954,466 shows a similar tool for use on flanged bolted joints, in which the tool clips around a feature adjacent to the nut or bolt head on which the backup wrench is positioned, so if the tool is suited to a specific arrangement of nut or bolt head size and relative flange outer surface, the backup wrench can resist rotation in both possible directions, i.e. loosening or tightening, without adjustment. However another disadvantage of such backup wrenches is that once a large torque has been applied to the fastener and has generated a reaction torque at the backup wrench, the lever portion of the backup wrench becomes jammed onto the torque reacting adjacent bolt or flange edge making it difficult or impossible and unsafe for the operator to overcome the frictional force of the lever portion and remove the backup wrench from the nut or bolt head. A threaded push bolt is optionally provided in the backup wrench of U.S. Pat. No. 5,954,466 to enable the backup wrench to be drawn off the nut or bolt head in these situations.
United Kingdom patent number GB2478955 discloses a backup wrench having a hexagonal socket including a threaded locking screw which can be tightened against one corner of a nut or bolt head over which the backup wrench is placed. This provides two advantages, firstly to enable any residual reaction torque in the backup wrench due to tightening of the bolt to be released after use by releasing the locking screw and secondly to lock the backup wrench onto the nut or bolt head to prevent it from falling off. Both of these advantages improve practicality and safety in use.
However another disadvantage of the above mentioned backup wrenches is their fixed hexagonal or polygonal socket size.
International patent application publication number WO2011/100256 discloses a backup wrench having an irregular hexagonal socket incorporating a threaded locking screw that in addition to locking the wrench to the nut or bolt and allowing it to be released after the fastener is torqued up, also allows for a range of sizes of hexagonal nuts or bolt heads to be operatively engaged and even ranges of other polygonal shaped nuts or bolt heads to be engaged through the use of alternate socket forms all incorporating the locking screw.
All of the above backup wrenches are for use on a single fastener, yet are typically used for the installation and maintenance of pressure boundary bolted joints incorporating multiple bolts, so either many such tools need to be installed on one side of the joint to enable the nuts or bolt heads on the opposite side of the joint to be adjusted in quick succession, or the one tool must be moved from bolt to bolt making the process extremely laborious and inefficient.
U.S. Pat. No. 5,429,465 discloses a plate incorporating multiple hexagonal sockets in a fixed spatial relationship to enable all the bolts of a single pressure boundary bolted joint to be adjusted in quick succession. However this tool is limited to use with a specific nut or fastener size, number and circumferential spacing.
Chinese patent number 102554869 discloses an open ended hexagonal socket backup wrench unit part, multiple such unit parts being attached together in a manner similar to links in a chain to enable all of the nuts or bolt heads in a circumferential arrangement to be engaged, where the number of unit parts or links is changed to suit the number of nuts or bolt heads on the joint. However while varying the number of unit parts or links allows a variable number of nuts or bolt heads to be engaged in circular arrangements in a range of diameters, the spacing between each nut or bolt head is fixed by the dimensions of the backup wrench unit parts.
It would therefore be desirable to provide a backup wrench spanner and/or a backup wrench arrangement that overcomes one or more of the disadvantages of the aforementioned arrangements.
Throughout this specification, the term backup wrench or backup wrench arrangement is used when referring to a tool used to provide grip and provide a reaction torque on a rotary fastener such as a bolt or nut. The term spanner or socket is used when referring to a fastener engaging means being the portion of the backup wrench or backup wrench arrangement that engages with the rotary fastener. For example, a spanner typically engages with at least two faces of a hexagonal nut or bolt head, whereas a socket typically engages with the six faces of a hexagonal nut or bolt head.
According to a first aspect of the invention there is provided a backup wrench arrangement including at least a first fastener engaging means including at least a first engagement surface and a second engagement surface for respectively engaging in use with at least two faces of a first nut or bolt head of a first fastener; wherein the first fastener engaging means allows rotation of the first nut or bolt head above a threshold of a reaction torque, by motion of the first fastener engaging means determined by a magnitude of the reaction torque and a force-deflection characteristic of a biasing arrangement acting directly or indirectly on the first fastener engaging means.
Another aspect of the present invention provides a backup wrench arrangement including at least a first fastener engaging means including at least a first engagement surface and a second engagement surface for respectively engaging in use with a respective face of a first nut or bolt head of a first fastener; wherein the first fastener engaging means allows rotation of the first nut or bolt head of the first fastener relative to the backup wrench arrangement when the first nut or bolt head is subjected to a reaction torque above a threshold reaction torque; the rotation of the first nut or bolt head being allowed by motion of the first fastener engaging means determined by a magnitude of the reaction torque and a force-deflection characteristic of a biasing arrangement acting directly or indirectly on the first fastener engaging means.
Force-deflection characteristic encompasses one or more of stiffness, load deflection, flex, resilience and may include an offset due to preload of the biasing arrangement.
The allowed rotation may be a continuous rotation while or whenever the reaction torque is greater than the threshold reaction torque. The continuous rotation may provide a continuous rotation torque release function where, if continued tightening torque is applied to the fastener, the nut can rotate. A load in the biasing arrangement may be selectively reducible or releasable to enable the backup wrench arrangement to be removed. For example, after the at least a first fastener has been tightened, the backup wrench may become jammed until at least a portion of the reaction torque or any residual reaction torque is released.
The threshold reaction torque may be between 5 and 50 percent or preferably between 10 and 30 percent of a target tightening torque to be applied to the first fastener. For example, the threshold reaction torque may be adjustable to a set point that is between 5 and 50 percent or preferably between 10 and 30 percent of the desired tightening torque.
The motion of the first fastener engaging means may be substantially radial (such as with respect to the fastener or nut or bolt head or relative to an array of fasteners e.g. a ring arrangement of fasteners), the biasing arrangement providing a biasing force to bias the first and second engagement surfaces of the first fastener engaging means onto the respective faces of the first nut or bolt head of the first fastener.
The biasing arrangement may include a flexible tension element, the biasing arrangement acting directly or indirectly on at least a second nut or bolt head to bias the first and second engagement surfaces of the first fastener engaging means towards the respective faces of the first nut or bolt head. For example, the biasing arrangement may act on the second nut or bolt head and on a third nut or bolt head. The second and third nuts or bolt heads may be either side of the first nut or bolt head towards which the first fastener engaging means is biased. Alternatively or additionally, the backup wrench arrangement may further include at least a second fastener engaging means, the at least a second fastener engaging means including a guide for partially locating the flexible tension element, each respective fastener engaging means being engaged with a respective nut or bolt head in use. The backup wrench arrangement may further include a tensioning arrangement for applying a tension to the flexible tension element in use. For example, the tensioning arrangement can be separate from the first fastener engaging means or incorporated into the first fastener engaging means.
The backup wrench arrangement may include a lever portion having a first loop portion at a first end, the first loop portion being arranged to pass around a portion of the first nut or bolt head in use; the first fastener engaging means being slidably located relative to the lever portion; the biasing arrangement acting between the lever portion and the first fastener engaging means; in use, the lever portion contacting a second nut to prevent rotation of the lever portion. The biasing arrangement may act directly or indirectly between the lever portion and the first fastener engaging means.
The biasing arrangement may include a resilient device, a load on the resilient device being adjustable to adjust the biasing force and thereby vary the reaction torque on the first nut or bolt head at which the first fastener engaging means deflects the resilient device and permits rotation of the first nut or bolt head. The resilient device may be or include, for example, a spring, such as a coil spring or torsion spring. The load on the resilient device may be adjustable using a bias force adjuster such as a preload screw.
The backup wrench arrangement may include a lever portion and may further include a second fastener engaging means, the lever portion having a second loop portion at a second end arranged to pass around a portion of a second nut in use; the second fastener engaging means being slidably located relative to the lever portion; the biasing arrangement acting between the lever portion and the second fastener engaging means. In use, the lever portion may contact another nut to prevent rotation of the lever portion. The biasing arrangement may act directly or indirectly between the lever portion and the second fastener engaging means. The biasing arrangement may have a single biasing arrangement acting on both the first and second fastener engaging means, or preferably the biasing arrangement may comprise separate first and second biasing arrangements.
At least one of the first and second engagement surface may include at least one ridge or groove. Preferably the at least one ridge or groove may be oriented in a direction substantially parallel with a primary axis of the first nut.
The backup wrench arrangement may further include a quick-release arrangement (such as a mechanism or device) for reducing and restoring the biasing force. Typically the quick release arrangement may be a lever mechanism providing an over-centre action to maintain the restored biasing force or restored biasing arrangement adjustment until the lever mechanism is operated to reduce or release the biasing force or adjustment.
The backup wrench arrangement may further include a lever portion, the motion of the first fastener engaging means being substantially a rotation relative to the lever portion, such relative rotation being inhibited by and/or requiring deflection of the biasing arrangement. For example, the first fastener engaging means may move primarily in a rotation about a primary axis of the first fastener. The biasing arrangement may include at least one resilient member. The first fastener engaging means may include or may be provided by a socket portion.
The lever portion may include a substantially circular hole into which the socket portion protrudes or is housed. The backup wrench may further include a detent mechanism including the resilient member, the detent mechanism acting between the lever portion and the socket portion to prevent said relative motion until the threshold reaction torque on the first nut is exceeded. Alternatively, the backup wrench may further include a ratchet mechanism including a pawl pivotally mounted to the lever portion, teeth on the socket portion and including the resilient member acting between the pawl and the lever portion, such that when in use the threshold reaction torque on the first nut is exceeded, one of the teeth on the socket provides a force generating a moment on the pawl that exceeds a moment applied to the pawl by the resilient member. The pawl may rotate and permit a limited rotation of the socket portion relative to the lever portion.
Alternatively, the lever portion may be attached to the socket portion by a pivot, the resilient member being connected directly or indirectly between the socket portion and the lever portion such that the relative rotation between the socket portion and the lever portion generates a deflection of the resilient member, the lever portion and resilient member being arranged such that when a reaction torque on the first nut generates a limit moment on the lever portion reacted by the second nut, the limit moment deflects the resilient member to permit sufficient relative rotation of the lever portion and the socket portion such that the lever portion passes between the first nut and the second nut.
The first nut or bolt head may be a first nut and the first fastener may further include a second nut or bolt head, a tightening torque being applied to the first fastener at the second nut or bolt head during use.
The first nut or bolt head may be a first bolt head, the fastener including a second nut, a tightening torque being applied to the first fastener at the second nut during use.
Another aspect of the present invention provides a spanner for a backup wrench arrangement, the spanner comprising: at least a first and a second engagement surface for engaging in use with two faces of a nut or bolt head or any other polygonal nut-like member, and a channel to receive a portion of a flexible tension element.
The spanner may further include a retaining arrangement to enable the spanner, in use, to be retained in proximity to a nut or bolt head with which the spanner is engaged. The retaining arrangement may be or include at least one magnet or magnetic portion. For example, at least one of the engagement surfaces may include a (or a respective) magnet forming the at least one magnetic portion to enable the spanner to be magnetically attracted or attached in use to a nut or bolt head that is formed from a material that is attracted to magnets. Additionally or alternatively, a magnet may be located elsewhere in the spanner such as in a face of the spanner that is substantially perpendicular to the first and second engagement surfaces to attract the spanner to a ferromagnetic material that is being clamped by a bolt to which the nut or bolt head is attached in use, such as for example a flange of a pressure joint.
Alternatively or additionally, the retaining arrangement may include a tie attachable to a first side of the spanner and attachable to a second side of the spanner such that an active length of the tie is adjustable to enable nuts or bolt heads of differing sizes to be retained. Alternatively, or additionally the retaining arrangement may include at least one spring clip and/or a resilient boot or socket. Alternatively, or additionally the retaining arrangement may include an adjustable or otherwise moveable jaw (including a spring-loaded jaw) to enable nuts or bolt heads of differing sizes to be accommodated.
The first and second engagement surfaces may be inner surfaces, having for example a 60 degree included angle, for engaging a first and a third face respectively of a hexagonal nut or bolt head. The spanner may further include a tensioning surface forming a base of the channel, the tensioning surface having for example an external angle of substantially 60 degrees to a plane extended from the first engagement surface and an external angle of substantially 60 degrees to a plane extended from the second engagement surface.
Alternatively, the first and second engagement surfaces may be inner surfaces, having for example a 120 degree included angle, for engaging a first and a second face respectively of a hexagonal nut or bolt head. The spanner may further include a tensioning surface forming a base of the channel, the tensioning surface having for example an external angle of substantially 30 degrees to a plane extended from the first engagement surface and an external angle of substantially 30 degrees to a plane extended from the second engagement surface.
The first and second engagement surfaces of the spanner may be symmetrical about a spanner centre plane. In that case, the channel may either have a flat base portion that is perpendicular to the spanner centre plane, or alternatively, have a curved base portion wherein a tangent to the curved base portion at a point where the spanner centre plane intersects the curved base portion is perpendicular to the spanner centre plane.
The spanner may be a terminating spanner further including a tensioning arrangement for applying a tension to the flexible tension element in use. The tensioning arrangement may include a ratchet pawl, a lever and/or a screw.
The spanner may further include a leash point. This can be any feature that enables a leash to be attached for safety, such as for example a hole, a loop or a hook.
Another aspect of the present invention provides a backup wrench arrangement comprising at least one spanner and a said flexible tension element. The spanner may comprise at least a first and a second engagement surface for engaging in use with two faces of a nut or bolt head or any other polygonal nut-like member, and a channel to receive a portion of the flexible tension element.
One of the at least one spanner may be a terminating spanner, the terminating spanner further including a tensioning arrangement for applying a tension to the flexible tension element in use. The magnitude of tension applied to the flexible tension element may be controlled to limit a reaction torque able to be reacted by the at least one spanner. The channel in the terminating spanner may guide the flexible tension element either to a termination point or to the tensioning arrangement. The at least one spanner may include the terminating spanner and may further include at least one intermediate spanner. The channel in the intermediate spanner or each intermediate spanner may guide the local alignment of flexible tension element relative to the respective intermediate spanner.
Alternatively, the spanner or one of the spanners may include a spanner centre plane, the first and second engagement surfaces of said spanner being symmetrical about the spanner centre plane. Said spanner further including a base portion of the channel of said spanner, the base portion being substantially perpendicular to the spanner centre plane in the region where the spanner centre plane intersects the base portion.
The backup wrench arrangement may include a tensioning arrangement for applying a tension to the flexible tension element in use. For example, the or all of the spanners may be similar (i.e. none includes a tensioning element) and the tensioning element may be provided separately, or as part of the flexible tension element. For example, the flexible tension element may include a ratchet strap, such as a webbing strap including at one end a ratchet-type tensioning arrangement into which the other end of the webbing strap is passed, then tightened, in use.
The backup wrench arrangement may be adjustable to the number of fasteners on a joint, such that the at least one spanner is a number of spanners equal to the number of fasteners. Alternatively, the at least one spanner may be multiple spanners, such that the flexible tension element can be in the channel of each of the multiple spanners, each of said spanners being engaged with a fastener on a joint, the spacing between the spanners being variable to accommodate for example different pitch circle diameter and/or pitch spacing of the fasteners. The one tool thereby accommodating a range of fastener arrangements for example, whilst being straightforward to position and operate, providing significant time savings in set up in addition to the time saved by the use of a multiple backup wrench tool for checking, tightening or releasing the fasteners in a joint.
Another aspect of the present invention provides a fastener backup method comprising the steps of: placing at least one spanner of a backup wrench arrangement on a respective nut or bolt head of an arrangement of fasteners; disposing a flexible tension element in a respective channel of the or each said spanner around the arrangement of fasteners; and applying a tension to the flexible tension element.
The spanner may comprise at least a first and a second engagement surface for engaging in use with two faces of a nut or bolt head or any other polygonal nut-like member, and a channel to receive a portion of the flexible tension element.
The step of placing at least one spanner of a backup wrench on a respective nut or bolt head of an arrangement of fasteners may include the step of attaching the or each spanner to the respective nut or bolt head, for example to retain the spanner in proximity to the respective nut or bolt head. The step of attaching the or each spanner to the respective nut or bolt head may include engaging at least one respective magnetic portion of the spanner with the nut, bolt head or an adjacent surface. Alternatively or additionally, the step of attaching the or each spanner to the respective nut or bolt head may include engaging a respective tie from a respective spanner around the respective nut or bolt head and back to the spanner.
The step of applying a tension to the flexible tension element may include applying a known or measured tension to the flexible tension element. The known tension may be a predetermined maximum tension, limited using a known means. The measured tension may be measured continuously and monitored, or measured as an optional repeated step. The benefit of applying a known or measured tension to the flexible tension element can be, for example, to permit the, or one of the spanners to displace (for example radially with respect to a ring of fasteners) when a reaction torque transmitted through a bolt to the nut or bolt head within said spanner exceeds a predetermined torque to enable said nut or bolt head to rotate. This helps to limit the maximum torque applied to the bolts during tightening and can be used to ensure that bolts are not overtightened or indicate that a bolt is seized, thus improving the safety and stability of the bolted joint. It can also limit the maximum load in the flexible tension element. The spanner may displace at least radially with respect to a ring of fasteners when the predetermined torque, which may be a threshold reaction torque, is exceeded. The reaction torque may be a portion of the torque transmitted through a bolt to the nut or nut head, the remainder being for example friction between the nut or bolt head and its engaging surface, being the surface it is pulled up against.
The arrangement of fasteners may be a ring of bolts clamping a pressure boundary bolted joint or a flanged connection such as for example a pressure pipe joint.
Another aspect of the present invention provides a backup wrench arrangement including: a spanner for a backup wrench arrangement, the spanner including at least a first and a second engagement surface for respectively engaging in use with at least two faces of a first nut or bolt head or any other polygonal nut-like member having at least four faces; and a biasing arrangement acting, in use, to provide a biasing force on the spanner to urge or bias the first and second engagement surfaces of the spanner towards a respective face of the first nut, the biasing arrangement deflecting to permit at least radial motion of the spanner relative to the first nut when a reaction torque on the first nut generates a force on the spanner that is greater than the biasing force.
Therefore, when the biasing force is overcome, the first nut can rotate, i.e. when the reaction torque is greater than a pre-set amount (or threshold) determined by the biasing arrangement.
The biasing arrangement may include a resilient member or a tensioning device or both.
The biasing arrangement may include a flexible tension element, the biasing arrangement acting directly or indirectly on at least a second nut or bolt head to bias the first and second engagement surfaces of the spanner towards the respective faces of the first nut. The biasing arrangement may act on the second nut or bolt head and on a third nut or bolt head (i.e. in addition to acting on the spanner). Alternatively, the spanner may be a first spanner and the backup wrench arrangement may further include at least a second spanner, the at least a second spanner including a channel for partially locating the flexible tension element, each respective said spanner being engaged with a respective nut or bolt head in use. Alternatively or additionally, the backup wrench arrangement may further include a tensioning arrangement for applying a tension to the flexible tension element in use. The tensioning arrangement can be separate from the first spanner or incorporated into the first spanner.
Alternatively, the backup wrench arrangement may include a lever portion having a first loop portion at a first end, the first loop portion being arranged to pass around a portion of the first nut in use, the spanner being slidably located relative to the lever portion, the biasing arrangement acting (directly or indirectly) between the lever portion and the spanner, in use the lever portion contacting a second nut to prevent rotation of the lever portion. The biasing arrangement may include a resilient member (such as for example a coil spring), a load on the resilient member being adjustable (using for example a bias force adjuster such as a preload screw) to adjust the biasing force and thereby vary the reaction torque on the first nut at which the spanner deflects the resilient member and permits rotation of the first nut.
The spanner may be a first spanner and the backup wrench arrangement may further include a second spanner, the lever portion having a second loop portion at a second end arranged to pass around a portion of a second nut in use, the second spanner being slidably located relative to the lever portion, the biasing arrangement acting (directly or indirectly) between the lever portion and the second spanner.
At least one of the first and/or second engagement surfaces may include at least one ridge or groove (for example, a groove oriented in a direction substantially parallel with a primary axis of the first nut). Alternatively, at least one of the first and/or second engagement surfaces may include at least a knurled region or other form of increased surface roughness.
Another aspect of the present invention provides a backup wrench arrangement comprising a socket portion, a lever portion and a resilient member: the socket portion being attached to the lever portion such that relative rotation is permitted, such relative rotation being inhibited by and/or requiring deflection of the resilient member; in use, the socket portion engaging with a first nut or bolt head and the lever portion engaging with a second nut or bolt head.
The first nut or bolt head may be of a first fastener and the second nut or bolt head may be of a second fastener.
The backup wrench arrangement may resist or react a tightening torque up to a limit determined at least in part by the spring deflection.
The lever portion may include a substantially circular hole into which the socket portion protrudes or is housed, the backup wrench further including a detent mechanism including the resilient member, the detent mechanism acting between the lever portion and the socket portion to prevent said relative motion until a threshold reaction torque on the first nut is exceeded.
Alternatively, the lever portion may include a substantially circular hole into which the socket portion protrudes or is housed, the backup wrench further including a ratchet mechanism including a pawl pivotally mounted to the lever portion, teeth on the socket portion and including the resilient member acting between the pawl and the lever portion, such that when in use a threshold reaction torque on the first nut is exceeded, one of the teeth on the socket provides a force generating a moment on the pawl that exceeds a moment applied to the pawl by the resilient member. In this arrangement, when the moment of the pawl generated by the teeth exceeds the moment applied to the pawl by the resilient member, the pawl rotates and permits a limited rotation of the socket portion relative to the lever portion.
Alternatively, the lever portion may be attached to the socket portion by a pivot, the resilient member being connected directly or indirectly between the socket portion and the lever portion such that the relative rotation between the socket portion and the lever portion generates a deflection of the resilient member, the lever portion and resilient member being arranged such that when a reaction torque on the first nut generates a limit moment on the lever portion reacted by the second nut, the limit moment deflects the resilient member to permit sufficient relative rotation of the lever portion and the socket portion such that the lever portion passes between the first nut and the second nut.
It will be convenient to further describe the invention by reference to the accompanying drawings which illustrate preferred aspects of the invention. Other embodiments of the invention are possible and consequently particularity of the accompanying drawings is not to be understood as superseding the generality of the preceding description of the invention.
In the drawings:
Referring initially to
The terminating spanner 8 is shown in more detail in
Using a torque wrench or measuring the tension in the chain 7 or other flexible tension element can be used to permit any of the spanners to displace (for example at least radially with respect to the ring of fasteners 8) when a torque transmitted through a bolt to the nut or bolt head within the spanner generates a reaction torque that exceeds a predetermined reaction torque (or threshold reaction torque) to enable said nut or bolt head to rotate. This can help prevent a bolt being over-tightened. It can also help indicate that a bolt is failing to tighten correctly due to being seized or galling. For example with a stud bolt, if the nuts on both the tightening side and on the spanner side are seized or galling, applying a torque puts the bolt into torsion but does not change the axial load on the bolt. So setting a known or predetermined tension in the chain 7 can allow the fastener to rotate relative to the spanner in either the over-tightening or the failure to tighten case, improving the quality assurance of the bolted joint through improving the safety and stability of the joint. Allowing the spanner to move relative to the fastener when a predetermined load is exceeded can also limit the load in the chain, further improving safety.
Typically, the reaction torque applied by the backup wrench or spanner to the nut with which it is engaged, is within 5 to 50 percent of the tightening torque applied on the tightening side of the fastener. More usually, the reaction torque is within 10 to 30 percent of the tightening torque. Much of the remaining 70 to 90 percent of the tightening torque is reacted by friction between the nut and the engaging surface that the nut is pulled up against. The exact reaction torque required is dependent on many factors, so being able to set the tension in the chain 7 effectively provides an adjustable set point, the chain tension being set to permit nut rotation at the desired reaction torque, which could for example be at 22 percent of the desired tightening torque. In that example, below 22 percent of the desired tightening torque, the spanner provides a reaction torque which reacts the torque from the nut with which it is engaged. But above that pre-set or threshold reaction torque of 22 percent of the desired tightening torque, the chain 7 of the backup wrench arrangement allows the spanner 8 to deflect sufficiently for the nut 5 to rotate relative to the spanner, indicating a problem. The problem can be that the nut 5 is seized onto the bolt 4 of the fastener 3 as mentioned above, or it can be another problem such that the desired tightening torque has been exceeded or that tightening of the fastener has proceeded after the desired bolt tension has been reached. The backup wrench arrangement can therefore also help prevent overtightening of fasteners.
The other spanners 6 consist primarily of the two engaging surfaces 11, 12 and the channel 30 in which the chain 7 sits, in use, as shown in
The two engaging surfaces 11, 12 of the spanner 6 in
A further variation on the base spanner part 6 is shown in
In the terminating spanner 8 in
In
Also shown in
The resilient types of retaining arrangement, i.e. the straps or ties 66 of
While the inside of the loop 151 can be a curved surface contacting only the points of the fastener or nut 5, it can be preferable to provide flat surfaces such as the first and second engagement surfaces 152, 153 shown, to engage the flat surfaces of the nut 5, as this requires a radial displacement of the lever portion 150 in addition to the radial displacement of the spanner 6 in the opposite direction, providing greater spring displacement.
While the backup wrench arrangement 1 of
While
The backup wrench arrangement in
Although the backup wrench arrangements of
So
Each of the arrangements in
In order to provide the continuous rotation torque release function of the other Figures, the lever portion 171 and the main body including the socket portion 170 need to be made small enough to clear a pipe to which the bolted flange is connected whilst still engaging with the second nut 142. While this may be possible in some applications it is not possible in all applications, limiting the applicability of this particular embodiment shown in
In
Although hexagonal nuts and bolt heads are shown in the above examples, the fastener nuts or bolt heads can be other shapes, such as square, or any other polygonal nut or bolt head. For hexagonal nuts and bolt heads, the spanner 6 can have the two engaging surfaces 11 and 12 adjacent as in
Any of the engaging surfaces such as 12 in
The backup wrench arrangement is shown on circular arrangements of bolts in
The flexible tension element can be a strap or wire rope for example in place of the chain 7. None of the spanners need to include a tensioning arrangement, since the tensioning arrangement can be provided either separately, or as part of the flexible tension element. For example, a ratchet strap can be used, in which case the flexible tension element can be a webbing strap and the tensioning arrangement is fixed to one end of the strap and in use has the other end of the strap passed into the tensioning arrangement and tightened.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017902718 | Jul 2017 | AU | national |
This application is a continuation of International Application Number PCT/AU2018/050715 filed Jul. 11, 2018, which claims priority to Australian Application No. 2017902718, filed Jul. 11, 2017, both of which are incorporated herein by reference in their entireties.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3342090 | Martin | Sep 1967 | A |
| 3535959 | Riza | Oct 1970 | A |
| 5337638 | Coss et al. | Aug 1994 | A |
| 6374706 | Newman | Apr 2002 | B1 |
| 6427558 | DeLand | Aug 2002 | B1 |
| 6955105 | Chen | Oct 2005 | B2 |
| 7895920 | Abunameh | Mar 2011 | B2 |
| 8925424 | Jacobs | Jan 2015 | B1 |
| 20130180364 | Galat | Jul 2013 | A1 |
| Number | Date | Country |
|---|---|---|
| 2239867 | Nov 1996 | CN |
| 102554869 | Jul 2012 | CN |
| 102008023657 | Nov 2009 | DE |
| WO 2007144691 | Dec 2007 | WO |
| WO 2019010531 | Jan 2019 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20200206883 A1 | Jul 2020 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/AU2018/050715 | Jul 2018 | US |
| Child | 16740094 | US |
