GB2507738A

GB2507738A - Telescopic arm and device for supporting a load

Info

Publication number: GB2507738A
Application number: GB201220035A
Authority: GB
Inventors: Alex Lau; Andrew Wills
Original assignee: Colebrook Bosson Saunders Products Ltd
Current assignee: Colebrook Bosson Saunders Products Ltd
Priority date: 2012-11-07
Filing date: 2012-11-07
Publication date: 2014-05-14
Also published as: GB201220035D0; WO2014072719A1

Abstract

A telescopic arm 10 for supporting a load, such as a monitor, defines a longitudinal axis x and comprises: a first arm portion 11; and a second arm portion 12, wherein the telescopic arm 10 is arranged to contract and/or extend along the longitudinal axis x by one of the arm portions moving linearly relative to the other arm portion, and wherein the first and second arm portions 11,12 are engaged one with the other such that linear motion of the first arm portion 11 relative to the second arm portion 12 causes rotation of the second arm portion 12 about the longitudinal axis relative to the first arm portion 11, and such that rotation of first arm portion 11 about the longitudinal axis relative to the second arm portion 12 causes linear motion of the second arm portion 12 relative to the first arm portion 11, and wherein the telescopic arm 10 further comprises a resilient bias arranged to resist rotation of the first arm portion 11 about the longitudinal axis relative to the second arm portion 12.

Description

TELESCOPIC ARM AND DEVICE FOR SUPPORTING A LOAD

Field of the Invention

The present invention relates to a telescopic arm, and in particular to a telescopic arm for supporting a load such as a monitor. The present invention also relates to a device for supporting a load such as a monitor. In particular, the device may be an arm configured such that, when pivoting, the arm allows a monitor attached to one end of the arm to maintain its orientation with respect to the other end of the arm.

Background to the Invention

Monitor arms come in a variety of shapes and sizes, depending on their intended function. One type of known monitor arm is a telescopic monitor arm comprising a pair of tubular members, one of which may telescope in and out of the other. Such monitor arms generally comprise a gas spring formed from a piston and cylinder arrangement that is arranged to support a monitor attached to one end of the arm through the use of compressed air.

If a gas spring malfunctions, however, one arm component can rapidly telescope into the other as pressure within the cylinder is lost. This can cause the monitor to fall rapidly, which may cause damage to it.

Another disadvantage with monitor arms using gas springs is that the cylinder within the arm is effectively sealed, such that cabling and wires for providing power to the monitor need to be routed or fed along a path exterior to the arm. This is inconvenient, as not only does it detract from the overall appearance of the arm, but can also be hazard for tripping, etc. There is therefore a need in the art to provide an improved telescopic arm that does not rely on a gas spring, and thereby seeks to address the above deficiencies.

Another type of monitor arm is one that may be attached at one end to a surface or anchoring platform (such as a wall or desk), and which may rotate or pivot about the attachment point. As the arm pivots in a vertical plane, it is desirable to maintain a monitor attached at the other end of the arm at a constant orientation. This has the advantage of allowing a user to dispense with the need to readjust the orientation of the monitor every time the arm is pivoted, US 2006/0226327 Al discloses such a device, wherein the orientation of a flat panel display with respect to the base of the arm remains unchanged during pivoting of the arm.

The present invention therefore also seeks to provide alternative means for implementing a device that may allow a load's orientation to be maintained throughout pivoting of the arm.

Summary of the Invention

In a first aspect of the present invention, there is provided a telescopic arm for supporting a load. The arm defines a longitudinal axis and comprises a first arm portion and a second arm portion. The telescopic arm is arranged to contract and/or extend along the longitudinal axis by one of the arm portions moving linearly relative to the other arm portion. The first and second arm portions are engaged one with the other such that linear motion of the first arm portion relative to the second arm portion causes rotation of the second arm portion about the longitudinal axis relative to the first arm portion, and such that rotation of first arm portion about the longitudinal axis relative to the second arm portion causes linear motion of the second arm portion relative to the first arm portion. The telescopic arm further comprises a resilient bias arranged to resist rotation of the first arm portion about the longitudinal axis relative to the second arm portion.

One of the two arm portions may be arranged to translate between a minimum and a maximum position, thereby defining retracted and extended positions or states of the telescopic arm, which may define the full stroke length of the arm. The arm thus has both a fully contracted state (e.g. when one arm portion is substantially fully within the other arm portion), and may then telescope outwards to a fully extended state. The arm is preferably designed to support a load of approximately 15 kg, though greater loads may be supported if desired.

The resilient bias may be disposed at least partially within each of the first and second arm portions.

Whilst the arm is preferably used to support monitors (especially computer monitors), flat-panel displays and the like, the arm may be used to support other loads, and in some embodiments may act as a table leg, for example.

The telescopic arm according to the invention advantageously dispenses with the need for gas springs as used in traditional monitor arms. This allows for cabling to be routed or fed through the interior of the arm, e.g. through the first and second arm portions. Furthermore, the arm of the present invention may dispense with the need for an articulated mid-joint as found in conventional monitor arms. Such mid-joints can be awkward to manipulate (especially when the arm is fully extended). By removing the mid-joint, the arm of the present invention is easier to use and more user-friendly.

The arm is effectively arranged such that a portion of the kinetic energy due to linear motion of the first arm portion relative to the second arm portion is translated into rotational kinetic energy of the first arm portion relative to the second arm portion. The resilient bias acts to resist this conversion of linear kinetic energy into the rotational kinetic energy. The resilient bias may dampen linear/rotational motion of one arm portion relative to the other.

Furthermore, the resilient bias may advantageously exert a relatively constant restoring or resistive force irrespective of the arm's extension. In other words, the arm may be configured such that the restoring force of the resilient bias opposing contraction/extension of the arm is relatively constant between the minimum and maximum extension states of the arm. This may allow a load supported by the arm to not be displaced along the longitudinal axis, irrespective of the arm's extension. Furthermore, the resistive force exerted by the bias may assist a user in moving the arm from a contracted state to an extended state, thereby providing relatively easy vertical movement of one arm portion relative to the other.

The resilient bias may comprise a torsion spring. A resilience of the resilient bias may be preset so as to prevent contraction of the telescopic arm when a predetermined load is applied to the telescopic arm along the longitudinal axis. Thus, the resilience of the resilient bias (e.g. the torsional stiffness or spring constant of the torsion spring) may be selected so that the arm may counterbalance a variety of different loads. Advantageously, the resilience of the resilient bias may be adjusted, and in particular may be adjusted during operation of the arm. For instance, the telescopic arm may comprise a ratchet-type device that actively increases or decreases the spring constant of the torsion spring so that monitors of different weights may be supported by the arm. For example, when a relatively lightweight (e.g. about 1 kg) monitor is attached to the arm, it may be preferable to set the resilience of the bias accordingly (which will also depend on the friction in the mechanism). If the resilience is set too high, a user wishing to vary the extension of the arm would have to apply a greater than normal force in order to overcome the resistance exerted by the bias. This could damage the arm by wearing out the spiral track, as explained below. The arm may also naturally telescope out to its fullest extension under the spring tension.

If, on the other hand, the resilience is set too low, or if the load applied to the arm is too great, then the load supported by the arm may overcome the resistance of the bias and may cause one arm portion to telescope into the other arm portion, and the load would not be supported.

At least a portion of the first arm portion may comprise a spiral track disposed along the longitudinal axis. The second arm portion may be arranged to engage with the spiral track when moving along the longitudinal axis relative to the first arm portion.

The spiral track provides an efficient means for allowing simultaneous rotation and linear movement of the first arm portion relative to the second arm portion. The first arm portion may be configured to engage with both the resilient bias and the spiral track. Thus, as the first arm portion moves linearly relative to the second arm portion, reciprocal rotation is induced as the first arm portion follows the spiral track. Through its engagement with the resilient bias, rotation of the arm is also resisted or opposed when the first arm portion is moved linearly relative to the second arm portion. This resistance to rotation allows for an efficient means of supporting a load.

As the first arm portion rotates and moves linearly relative to the second arm portion, the restoring force exerted by the spring on the first arm portion may increase slightly. Thus, it is advantageous to select the pitch of the spiral track such that, as the first arm portion rotates relative to the second arm portion, the first arm portion carries out a small number of rotations relative to the number of windings of the torsion spring. This allows the change in force to be rendered largely negligible, by selecting an appropriate pitch of the spiral track.

Alternatively, or in addition to the pitch of the track being varied as explained above, the number of windings of the torsion spring may also be adjusted. This may allow the change in force exerted by the spring on the first arm portion to be minimal with respect to the length of the arm's stroke. This may in turn provide for a near constant force to be exerted by the torsion spring when resisting movement of the first arm portion. Thus, a load of a predetermined weight may be supported by the arm irrespective of the arm's extension.

A pitch of the spiral track, relative to the longitudinal axis, may vary along the longitudinal axis. This may be done to compensate the change in restoring force exerted by the spring over the whole length of the arm's extension. Varying the pitch of the spiral track may vary the frictional force between the first arm portion and the second arm portion. This may be useful if the arm has been designed such that a not insignificant change in restoring force is exerted by the spring throughout the entire stroke of the arm. If this is the case, it may be advantageous to vary the pitch of the track along the longitudinal axis of the arm, thereby adjusting the frictional force between the first and second arm portions accordingly, and effectively counterbalancing the change in restoring force.

An end of the resilient bias may be positionally fixed in relation to one of the arm portions. This may be achieved through any suitable means, such as by creating a small aperture in one of the arm portions into which one end of resilient bias may be inserted. By positionally fixing one end of the bias relative to one of the arm portions, the resilient bias may act to dampen the stroke of the first arm portion relative to the second arm portion.

The engagement of the first arm portion with the second arm portion may be arranged to generate a friction force on the first and second arm portions that resists movement of the first arm portion along the longitudinal axis relative to the second arm portion.

A minimum of friction is advantageous so as to accommodate slight variations in the weight of the load applied to the arm. In particular, the friction force may counterbalance a restoring force exerted by the resilient bias on the first and second arm portions so as to prevent movement of the first arm portion along the longitudinal axis relative to the second arm portion when a load below a predetermined threshold is applied in the longitudinal direction. The resilient bias, according to Hooke's law, for small displacements from its equilibrium, exerts a restoring force proportional to its displacement from equilibrium. Thus, Ihe grealer the load applied to Ihe arm, Ihe grealer Ihe resistance exerted by the resilient bias, and the greater the friction force between the first and second arm portions.

For example, whilst the resilience of the bias may be set to support a 2 kg monitor, the friction between the first and second arm portions may be such that a weight of 1.9 -2.1 kg may be supported by the arm. Thus, slight variations in the weight of the load will not cause the arm to contract (e.g. if a piece of office stationary were affixed to the monitor, the monitor would remain supported by the arm). Monitor cables are a typical example of loads that are not properly considered during the load setting, and therefore often require a range on all load settings.

A magnitude of the friction force may be at least partially determined by a pilch of Ihe spiral track and/or a resilience of the resilient bias. As explained above, the magnitude of the friction force may be tailored by adjusting the resilience of the bias and/or the pitch of the spiral track. For instance, by decreasing the pitch of the track, a greater resilience is required to overcome the friction force between the first and second arm portions.

Whilst the telescopic arm has been described as having two arm portions, it is to be understood that more than two arm portions may be used. Each arm portion would thus be configured to telescope relative to the other arm portions.

In particular, the telescopic arm may further comprise a third arm portion.

The telescopic arm may be further arranged to contract and/or extend along the longitudinal axis by one of the first, second or third arm portions moving linearly relative to the other arm portions. The second and third arm portions may be engaged one with the other such that linear motion of the second arm portion relative to the third arm portion causes rotation of the third arm portion about the longitudinal axis relative to the second arm portion, and such that rotation of the second arm portion about the longitudinal axis relative to the third arm portion causes linear motion of the third arm portion relative to the second arm portion.

Furthermore, the resilient bias may be further arranged to resist rotation of at least one of the first, second and third arm portions about the longitudinal axis.

Advantageously, this embodiment of the invention allows for greater extension of the arm per unit rotation of the arm portions. Thus, as the first arm portion rotates relative to the longitudinal axis, it induces relative linear motion in both the second and third arm portions.

At least a portion of the first arm portion may comprise a spiral track disposed along the longitudinal axis. The second and third arm portions may be each arranged to engage with the spiral track when moving along the longitudinal axis relative to the first arm portion. The spiral track may comprise first and second track portions, each track portion running in a different rotational direction to the other track portion. Alternatively, at least a respective portion of each of the second and third arm portions may comprise a spiral track disposed along the longitudinal axis. The first arm portion may be arranged to engage with each of the spiral tracks disposed on the second and third arm portions when moving along the longitudinal axis relative to the second and third arm portions.

Thus, a spiral track can be disposed on only a single arm portion, with the other two arm portions both engaging with the track. This advantageously simplifies the manufacture of the arm.

The first arm portion may be arranged to house the resilient bias. This offers a measure of protection to the resilient bias. Furthermore, the resilient bias may be further arranged to translate or otherwise move with the first arm portion when the first arm portion moves along the longitudinal axis relative to the second arm portion.

The first arm portion may comprise an inner arm portion and an outer arm portion. The inner and outer arm portions may be rotatable relative to each other about the longitudinal axis. Each end of the resilient bias may coupled a respective one of the inner arm portion and the outer arm portion. The inner arm portion may be received within the outer arm portion with the resilient bias housed therein, effectively forming a cartridge or housing for the resilient bias.

During linear translation of the first arm portion relative to the second and third arm portions, the inner arm portion may be arranged to simultaneously rotate relative to the outer arm portion, for example by following tracks in the second and third arm portions. At the same time, the outer arm portion may be prevented from rotating with the inner arm portion, and instead may translate linearly relative to the second and third arm portion, for example by following vertical slots, grooves or channels formed in the second and third arm portions. If each end of the resilient bias / torsion spring is coupled or fixed to a respective one of the inner and outer arm portions, the spring's tension may increase, thereby resisting rotation of the first arm portion relative to the second and third arm portions. The tensioning of the spring/bias as the arm contracts/expands provides an effective means for supporting a load applied to the arm.

At least one of the arms portions may comprise rollers for guiding the at least one of the arm portions along at least one of the spiral tracks. The rollers may take any form suitable to facilitate the guiding of the arm portions along a spiral track, and may take the form of ball bearings or wheels. In another embodiment, the rollers may comprise teeth that mesh with corresponding teeth on the spiral track, similar to a rack and pinion arrangement.

Whilst the telescopic arm has been described with the first arm portion moving relative to the second arm portion, a person skilled in the art will recognise that it is the relative motion of one arm portion with respect to the other that is important. Thus, where the invention is described with the first arm portion moving (either linearly or rotationally about the longitudinal axis) relative to the second arm portion (or indeed any other arm portion), it is to be understood that the invention may be equivalently described with the second arm portion moving relative to the first arm portion.

It should furthermore be noted that any feature described above may be used with any particular aspect or embodiment of the invention.

According to the second aspect of the present invention, there is provided a device for supporting a load. The device comprises an arm having first and second ends, and defines a longitudinal axis. The device further comprises first and second support members, and first and second worm drives coupling each end of the arm to a respective support member. The arm is arranged to pivot at the first end and relative to the first support member such that the first worm drive operates to cause the arm to rotate about the longitudinal axis, thereby operating the second worm drive to cause the arm to pivot at the second end and relative to the second support member.

The arm may comprise a rod or internal shaft disposed within an outer housing. Each support member may comprise a worm arranged to engage with a worm gear (e.g. by meshing with the teeth of the worm gear), thereby forming a respective one of the worm drives. The worm may be fixed to the support member. Each end of the arm may comprise a worm gear arranged to engage with a worm, thereby forming a respective one of the worm drives. Each worm gear may be disposed around a periphery of the arm, and may be fixed to the arm.

The gear ratio of each of the worm drives may be arranged such that, when the arm pivots at the first end and relative to the first support member, an orientation of the second support member relative to the first support member is maintained.

According to the second aspect of the present invention, there is provided a further device for supporting a load. The device comprises first and second support members. The device further comprises an arm defining a longitudinal axis. The arm is arranged to pivot relative to each of the first and second support members about a respective pivot axis. The arm further comprises one or more first coupling members coupling the first support member to the arm, and one or more second coupling members coupling the second support member to the arm.

Each coupling member comprises a longitudinal portion disposed substantially parallel to the longitudinal axis, and an orthogonal portion disposed substantially parallel to the pivot axes. Each longitudinal portion is further rotatable about the longitudinal axis, and each orthogonal portion is spaced from its respective pivot axis. The arm is arranged such that, when pivoting about the first pivot axis and relative to the first support member, the first coupling member cooperates with the first support member and the arm to cause the arm to rotate about the longitudinal axis, thereby causing the arm to cooperate with the second coupling member so as to cause the arm to pivot about the second pivot axis and relative to the second support member.

In a preferred embodiment, a pair of coupling members is used to couple each support member to the arm. For a given pair of longitudinal portions, each longitudinal portion of the pair may be received within the arm on opposite sides of the longitudinal axis. Similarly, for a given pair of orthogonal portions, each orthogonal portion of the pair may be disposed on opposite sides of a respective pivot axis.

Each longitudinal portion may be constrained in cross-section relative to the arm. In other words, the distance separating any point along a longitudinal portion may remain constant relative to the longitudinal axis of the arm. Similarly, each orthogonal portion may be axially constrained relative to its respective pivot axis (e.g. every point along the orthogonal portion may be at a constant distance from the pivot axis).

The device may be arranged such that, when the arm pivots at the first end and relative to the first support member, an orientation of the second support member relative to the first support member is maintained.

Each orthogonal portion may be arranged to translate relative to its respective support member and parallel to its respective pivot axis during pivoting of the arm. Similarly, each longitudinal portion may be arranged to translate relative to the arm and parallel to the longitudinal axis during pivoting of the arm.

According to the second aspect of the invention, there is provided a further device for supporting a load. The device comprises an arm having first and second ends, and a rod, the arm defining a longitudinal axis. The device further comprises first and second support members coupled to the first and second ends of the arm, and first and second driving members engaged with the rod, each driving member being coupled to a respective support member at a pivoting point located off the longitudinal axis. The arm is arranged to pivot about the first end and relative to the first support member such that the first driving member pivots relative to the first support member about the first pivoting point so that the engagement of the first driving member with the rod causes the rod to rotate about the longitudinal axis, thereby causing the second driving member to pivot relative to the second support member about the second pivoting point, such that the arm pivots at the second end and relative to the second support member.

Thus, as the arm pivots relative to the first support member, the engagement of the rod with the first driving member, and the coupling of the first driving member to the first support member, may cause the arm rod to rotate about its longitudinal axis. This rotation of the rod then causes the second driving member to pivot relative to the second support member about the second pivoting point, allowing the arm to pivot at the second end and relative to the second support member.

The arm may further comprise a restraining mechanism arranged such that the rod is constrained longitudinally within the arm. The restraining mechanism may take the form of a collar disposed at an end of the rod and through which fixing means connect to the collar to the first support member, allowing the arm to pivot relative thereto.

In one embodiment, the rod is threaded, and each driving member comprises an internal thread arranged around the threaded rod. The pitch of the threaded portions on the driving members and the rod itself may be arranged to vary the rate of pivoting of the rod relative to the first and second support members.

The arm may be further arranged such that, when the first driving member pivots relative to the first support member, the first driving member is drawn along the longitudinal axis and translates relative to the threaded rod. When the threaded rod rotates about the longitudinal axis, the second driving member may be drawn along the longitudinal axis and translate relative to the threaded rod.

Each driving member may comprise a driving portion in engagement with the threaded rod, and a link member coupling each driving portion to its respective support member at its respective pivoting point. The link members may be of fixed length, and may assist in causing the driving portions to move along the threaded rod as the arm pivots relative to the first/second support members.

In another embodiment, the driving member may comprise a pair of driving portions linked together with linking members disposed between the driving portions. This driving member may be arranged such that rotation of one driving portion may cause translation of the other driving portion relative thereto. One driving portion may be pivotally connected to a support member, whilst the other driving portion may be coupled to an end of the rod.

The first and second support members may be coupled to the first and second ends of the arm at points located on the longitudinal axis.

According to the second aspect of the invention, there is provided a further device for supporting a load. The device comprises an arm having first and second ends, and first and second support members coupled to the first and second ends at first and second pivoting points. The arm is arranged to pivot about each of the first and second pivoting points and relative to each of the first and second support members. Each of the first and second support members comprises an attachment point spaced from its respective pivoting point. The device further comprises a linking member connecting the first and second support members via the first and second attachment points. The linking member imparts movement of the first support member pivoting relative to the arm to the second support member, thereby causing the second support member to pivot relative to the arm The device may be arranged such that, when the arm pivots about the first and second pivoting points, the linking member restrains the pivoting of the first and second support members relative to the arm so as to maintain a constant distance between the first and second attachment points. In other embodiments, the rate of pivoting of the second support member relative to the arm may be different to the rate of pivoting of the first support member relative to the arm, such that distance between the first and second attachment points varies.

The linking member may be a Bowden cable (e.g. comprising an inner cable disposed within an outer sheath), as typically used for example in bicycle brake systems. The Bowden cable may be used to transmit a pull/push force along its length. Thus, when the arm pivots relative to the first support member, the extension/contraction of the inner cable at one end of the linking member may be translated into corresponding contraction/extension of the cable at the other end of the linking member. This may allow the orientation of the second support member relative to the first support member to remain constant.

The arm may further comprise a pair of guide points for guiding the linking member. The guide points may take the form of loop or anchoring points, able to guide the linking member therethrough. The device may further comprise a sheath arranged about the linking member, and the sheath may be attached between the pair of guide points. In some embodiments, the distance between one of the attachment points and a guide point may increase during pivoting of the arm, and a distance between the other attachment point and another guide point may correspondingly decrease.

The linking member may be one of: a cable, a string, a cord, and a wire.

Other types of linking members may be used and fall within the scope of the invention.

According to the second aspect of the invention, there is provided a further device for supporting a load. The device comprises an arm having first and second ends. The arm defines a longitudinal axis, and each of the first and second ends comprises a bearing surface or edge. The arm also comprises first and second support members, each support member being constrained in engagement with a respective bearing surface or edge of the arm. The arm is arranged to pivot at the first end and relative to the first support member such that the first support member cooperates with the first bearing surface or edge to cause the arm to rotate about the longitudinal axis, thereby causing the second bearing surface or edge to cooperate with the second support member to cause the arm to pivot at the second end and relative to the second support member.

Each bearing edge of the arm may be formed by sectioning each end of the arm at a non-normal angle to the longitudinal axis. Thus, the second aspect of the invention also provides an arm having first and second ends, and defining a longitudinal axis, with each of the first and second ends being sectioned at a non-normal angle to the longitudinal axis. The device further comprises first and second support members constrained in engagement with the first and second ends. The arm is arranged to pivot at the first end and relative to the first support member such that the first sectioned end cooperates with the first support member to cause the arm to rotate about the longitudinal axis, thereby causing the second sectioned end to cooperate with the second support member to cause the arm to pivot at the second end and relative to the second support member.

Each end of the arm may be sectioned at an angle of 45° relative to the longitudinal axis.

The device may be arranged such that, when the arm pivots at the first end and relative to the first support member, an orientation of the first support member relative to the second support member is maintained.

According to the second aspect of the invention, there is also provided a further device for supporting a load. The device comprises an arm having first and second ends, and defining a longitudinal axis, each of the first and second ends comprising a bearing surface. The arm further comprises first and second support members, each support member comprising a male member constrained in engagement with a respective bearing surface of the arm. The arm is arranged to pivot at the first end and relative to the first support member such that the first male member cooperates with the first bearing surface to cause the arm to rotate about the longitudinal axis, thereby causing the second bearing surface to cooperate with the second male member to cause the arm to pivot at the second end and relative to the second support member.

Each end of the arm may further comprise an additional bearing surface such that each end of the arm comprises a pair of bearing surfaces spaced one from the other, thereby forming at each end of the arm a female portion for receiving therein a respective male member.

Each male portion may be cylindrical, and each pair of spaced bearing surfaces may form an opening having a size equal to the diameter of the respective male member received within the female portion.

Each female portion may comprise a slot extending through the arm.

Each male portion may comprise a rod extending through a respective female portion of the arm. Each male portion may be fixed relative to its respective support member. Each male member may extend at a non-normal angle relative to the longitudinal axis, and in particular each male member may extend at an angle of 45° relative to the longitudinal axis.

In each of the above-described embodiments, the first support member may be arranged to attach the device to a fixed platform, such as a desk or a wall. The second support member may be arranged to receive a load to be supported by the device. The load is typically a monitor such as a flat-panel display or tablet computer, but alternatively may be a laptop computer or other display means whose position may be readily adjusted by a user. Furthermore, each device may be arranged such that, when the arm pivots at the first end of the arm and relative to the first support member, an orientation of the first support member relative to the second member may be maintained. Furthermore, the arms of the above load-supporting devices may be telescopic.

A person skilled in the art will understand that, whilst the pivoting action of the arm has largely been described relative to the first support member, the arm may equally well be described as pivoting relative to the second support member.

Thus, a person skilled in the recognise that it is the motion of one support member relative to the other that is important, and that each of the above-described devices may be configured such that pivoting of the arm relative to the second support member may cause corresponding pivoting of the arm relative to the first support member.

It should be noted that any feature described above may be used with any particular aspect or embodiment of the invention.

It should furthermore be noted that the first aspect of the invention may be combined with the second aspect of the invention, so as to create a device having a telescopic arm that may be used to support a load. The load's orientation at one end of the arm relative to the other end of the arm may be maintained throughout pivoting or rotation of the arm in a vertical plane.

Brief Description of the Drawings

Several embodiments of the present invention will now be described by way of example and with reference to the following drawings, in which: Figure 1 is a perspective view of the constituent components of a telescopic arm according to a first embodiment of the first aspect of the present invention; Figure 2A is a perspective view of the telescopic arm of Figure 1, shown assembled in its contracted state; Figure 2B is a perspective view of the telescopic arm of Figure 2A, shown in an extended state; Figure 3 is a perspective view of the constituent components of a telescopic arm according to a second embodiment of the first aspect of the present invention; Figure 4A is a perspective view of the telescopic arm of Figure 3, shown assembled in its contracted state; Figure 4B is a perspective view of the telescopic arm of Figure 4A, shown in an extended state; Figure 5 is a perspective view of the constituent components of a telescopic arm according to a third embodiment of the first aspect of the present invention; Figure 6A is a perspective view of the telescopic arm of Figure 5, shown assembled in its contracted state; Figure 6B is a perspective view of the telescopic arm of Figure 6A, shown in an extended state; Figure 7 is a perspective view of the constituent components of a telescopic arm according to a fourth embodiment of the first aspect of the present invention; Figure 8A is a perspective view of the telescopic arm of Figure 7, shown assembled in its contracted state; Figure 8B is a perspective view of the telescopic arm of Figure 8A, shown in an extended state; Figure 9 is a perspective view of the constituent components of a telescopic arm according to a first embodiment of the first aspect of the present invention; Figure 1OA is a perspective view of the telescopic arm of Figure 9, shown assembled in its contracted state; Figure lOB is a perspective view of the telescopic arm of Figure bA, shown in an extended state; Figure 11 is a perspective view of a device for supporting a load, according to the second aspect of the present invention; Figure 12 is a perspective view of a device for supporting a load, according to a first embodiment of the second aspect of the present invention; Figure 13 is a perspective view of the worm drive of the device of Figure 12; Figure 14 is a perspective view of a device for supporting a load, according to a second embodiment of the second aspect of the present invention; Figure 15 is a magnified view of the first support member, first coupling members and arm of the device of Figure 14; Figures 1 6A -1 6C are perspective views of a device for supporting a load, according to a third embodiment of the second aspect of the present invention; Figure 17 is a perspective view of one end of the device of Figures 1 6A - 16C, showing the interrelated movement of the arm relative to the first support member, the driving portion and the inner column; Figure 18 is a perspective view of the device of Figures 16A -17, illustrating an alternative embodiment of the driving member; Figures 1 9A -190 are perspective views of a device for supporting a load, according to a fifth embodiment of the second aspect of the present invention; Figure 20A is a perspective view of the constituent components of a device for supporting a load, according to a sixth embodiment of the second aspect of the present invention; Figure 20B is a perspective view of the device of Figure 20A, shown assembled; Figure 21 is a perspective view of the device of Figures 20A and 20B, shown with the arm in different pivotal states relative to the first support member; Figures 22A -220 are perspective views of a device for supporting a load, according to a seventh embodiment of the second aspect of the present invention; and Figure 23 is a top-down view of the device of Figures 22A -22G.

Detailed Description of Preferred Embodiments

Whilst various embodiments of the present invention are described below, the invention is not limited to these embodiments and variations of these embodiments may well fall within the scope of the invention which is to be limited only by the appended claims.

According to a first embodiment of the first aspect of the invention, there is provided a telescopic arm as shown in Figure 1. In particular, Figure 1 illustrates the constituent components of telescopic arm 10.

Telescopic arm 10 comprises a pair of arm portions, referred to herein as inner column 11 and outer column 12, and a resilient bias in the form of torsion spring 13, and defines a longitudinal axis X. Inner and outer columns 11 and 12 are hollow cylinders, and inner column 11 is arranged to telescope in and out of outer column 12, by moving relative to outer column 12 along axis X. Outer column 12 comprises spiral track 14, consisting of a plurality of grooves 15 running along the interior surface of outer column 12. Whilst inner column 11 is seen to have a diameter less than that of outer column 12, it is to be understood that, in other embodiments, outer column 12 could telescope in and out of inner column 11, with a spiral track disposed along the outer surface of outer column 12, for example.

Inner column 11 comprises ball bearing rollers 16 on its exterior surface.

Rollers 16 are arranged to sit within grooves 15 of spiral track 14. Inner column 11 also comprises vertical, linear track 17, running from the topmost end of inner column 11 to approximately halfway down the length of inner column 11.

Torsion spring 13 is substantially of equal height as inner and outer columns 11 and 12. Torsion spring 13 also comprises ball bearing roller 19 arranged to be received within vertical track 17.

Figure 2A shows telescopic arm 10 in its fully contracted state. Torsion spring 13 is housed and sits within inner and outer columns 11 and 12. One end (end 18) of torsion spring 13 is inserted into a corresponding slot in outer column 12, thereby fixing torsion spring 13 to outer column 12. The other end of torsion spring 13 (best seen in Figure 2B) comprises roller 19 (much like ball bearing rollers 16) engaged with vertical track 17 of inner column 11.

In its extended state, as seen in Figure 2B, a load may be supported at the topmost end of inner column 11, and exerts a downwards force on arm 10 in the longitudinal direction X. Inner column 11 is free to move downwards along vertical track 17. When moving vertically downwards along longitudinal direction X, inner column 11 is also constrained to follow spiral track 14, by rotating about longitudinal axis X. The resilience (e.g. torsional stiffness) of torsion spring 13 is set to resist a predetermined load applied to arm 10 in longitudinal direction X. Thus, provided the load is below this threshold, inner column 11 will not translate relative to outer column 12.

Should a user wish to lower inner column 11 with respect to outer column 12, they may apply a force to arm 10 along longitudinal direction X. This will cause the effective load to increase and thus will cause the resistance of torsion spring 13 to be overcome. Inner column 11 will thus rotate by being guided along spiral track 14. As inner column 11 rotates relative to outer column 12, it also translates relative to outer column 12, decreasing the extension of arm 10.

Now referring back to Figure 2A, inner column 11 has been fully pushed into outer column 12. Whilst the resistance afforded by torsion spring 13 -20 -increases as inner column 11 is moved within outer column 12, this increase is marginal and is not enough to overcome the frictional engagement between inner column 11 and outer column 12. As can be seen from Figures 2A and 2B, the number of windings contained in spring 13 is much greater than the number of revolutions performed by inner column 11 as it translates from the extended position to its contracted position.

To summarise, in this embodiment, outer column 12 comprises spiral track 14. Inner column 11 tensions spring 13 as it moves down within outer column 12.

Inner column 11 rotates in spiral track 14 which in turn rotates torsion spring 13 that has one end 18 fixed in outer column 12 and another end 19 fixed in inner column 11. The act of rotating spring 13 increases the spring force acting against rotation of inner column 11. In equilibrium, the component of load on the end of inner column 11 should equal the component of the spring force attempting to unwind the tensioned spring. Under motion, this spring force should assist the motion to provide easy vertical movement.

Figure 3 shows a second embodiment of the inventive telescopic arm, and in particular shows the constituent components of arm 20. In this embodiment, arm 20 is similar to arm 10 apart for the addition of upper column 22b. Lower column 22a comprises track 24a whose windings run clockwise about longitudinal axis X and within an interior surface of lower column 22a. Upper column 22b comprises spiral track 24b disposed along an interior surface of upper column 22b. Spiral track 24b runs from the topmost edge of upper column 22b to approximately halfway down upper column 22b. The rotational direction of spiral track 24b about longitudinal axis X is anticlockwise when viewed vertically down axis X. Ball bearing rollers 26a and 26b, disposed at the lower and upper ends of inner column 21, are configured to be received in grooves 25a and 25b of tracks 24a and 24b of lower and upper columns 22a and 22b.

As seen in Figures 4A and 4B, arm 20 is depicted in both its contracted and its extended state, respectively. Starting from the contracted state shown in Figure 4A, upper column 22b may be translated vertically relative to inner column 21 and lower column 22a (e.g. by a user pulling upwards on upper column 22b).

-21 -Rotational motion is induced in inner column 21 as inner column 21 is guided along spiral track 24a of lower column 22a and spiral track 24b of upper column 22b. The lower end of torsion spring 23 is fixed into a receiving aperture disposed at the bottom of lower column 22a, whilst the upper end of torsion spring 23 is allowed to translate along vertical track 27 of inner column 21.

Because of the resilience of torsion spring 23, arm 20 may be configured to maintain its expanded state (Figure 4B) if, for example, the user were to cease pulling upwards on upper column 22b. Torsion spring 23 is engaged with inner column 21 via roller 26b being received in vertical track 27. Thus, torsion spring 23 resists rotation of inner column 21 relative to lower and upper columns 22a and 22b. Therefore, for a given torsional stiffness of torsion spring 23, a predetermined load may be supported by arm 20.

Whilst this embodiment has been described such that arm 20 is converted from its contracted to its extended state, a person skilled in the art will understand that a load may be applied to arm 20 whilst in its extended state, such that arm may telescope back into its contracted state. A person skilled in the art will furthermore appreciate that it is equally possible for both lower and upper columns 22a and 22b to rotate relative to inner column 21 as arm 20 contracts/expands. Effectively, inner column 21 would then remain stationary relative to upper and lower columns 22a and 22b as they translate linearly along axis X. In the embodiment of Figures 4A and 4B, twice as much extension of arm is achieved per unit of rotation of inner column 21. This is due to the rotation of inner column 21 inducing translation of both lower column 22a and upper column 22b. In this embodiment (as well as those discussed below), during extension of arm 20, there is a constant overlap between upper column 22b, inner column 21 and lower column 22a. This improves the strength and stability of the arm.

To summarise, in this embodiment, both upper and lower columns 22a and 22b comprise spiral paths 24a and 24b disposed along them. These columns overlap but generally do not rotate relative to one other. They are joined by an intermediary runner column (e.g. inner column 21) that comprises bearings -22 - 26a and 26b on both ends so that it may run through upper and outer columns 22a and 22b at an equal rate. Torsion spring 23 has one end fixed into lower spiral column 22a and the other end fixed to the intermediary spiral column 21.

As with the previous embodiment, as the upper column 22b moves vertically, the inner intermediary column 21 rotates in the spiral tracks 24a and 24b causing spring 23 to rotate and thereby increase its spring force. However, as the intermediary column rotates, it moves at an equal rate in both spiral tracks 24a and 24b. This results in half the rotation of the spring producing twice as much vertical movement. The overlapping nature of the columns provides a more solid mechanism that is less likely to separate or topple.

Figure 5 shows the components of an arm according to a third embodiment of the present invention. Arm 30 comprises guide member 31', lower column 32a, inner column 31, upper column 32b, spring holder 33', torsion spring 33 and bearing face 38.

Spring holder 33' is inserted into the interior of torsion spring 33, with an end of spring 33 being received in slot 33'a at the base of spring holder 33'.

Thus, one end of spring 33 is positionally fixed relative to spring holder 33.

Spring holder 33', with spring 33 contained therein, is then inserted into inner column 31. The other end of spring 33 is fixed to inner column 31. Bearing face 38, which has an annular form, may then be positioned so as to firmly house spring holder 33' and spring 33 within inner column 31.

Inner column 31 comprises lower track portion 34a and upper track portion 34b. Each track portion winds about an outer surface of inner column 31, and in a direction opposite to the other track portion. In the present embodiment, lower track portion 34a winds clockwise whilst upper track portion 34b winds anticlockwise, relative to longitudinal axis X. Guide member 31' comprises vertical grooves 37 arranged to guide spring holder 33' vertically along longitudinal axis X. Lower column 32a comprises a pair of vertical slots 27 that are arranged to receive bearings or rollers 36b attached to upper column 32b.

Lower and upper columns 32a and 32b each have respective ball bearing rollers 36a and 36b disposed on their interior surfaces. Lower column 32a is fit -23 -over inner column 31 such that rollers 36a are received within lower track portion 34a of inner column 31. Upper column 32b is then fit over lower column 32a such that its rollers 36b are received within the grooves of upper track portion 34b.

In previous embodiments, the telescopic arm was described in use as converting from its contracted to an extended state. In the present embodiment, the arm in use is described as converting from an extended state to its contracted state. In Figure 6B, there is shown arm 30 in an extended state. Arm 30 may contract to the position shown in Figure 6A by a user exerting a force on arm 30 in its longitudinal direction X. For example, a user my press down on upper column 32b in direction X. Because of the spiral nature of track portions 34a and 34b, the downwards force exerted by upper column 32b on inner column 31 will drive inner column 31 to rotate. Inner column 31 is arranged to rotate relative to spring holder 33'. Therefore, as inner column 31 rotates, spring 33 resists rotation of inner column 31. Rotation of inner column 31 in turn drives inner column 31 (with spring holder 33' and spring 33 affixed thereto) to translate downwards. Spring holder 33', inner column 31 and bearing face 38 may move as one vertically downwards, via grooves 37 of guide member 31'. Thus, arm 30 may telescope into its contracted state as shown in Figure 6A. Note that rollers 36b of upper column 32b may be received in slots 37 of lower column 32a as lower column 32a telescopes within upper column 32b.

As in the previously described embodiments, the resilience of spring 33 ensures that, unless the load applied to arm 30 exceeds a predetermined threshold, rotation of inner column 31 is opposed to the extent that arm 30 will remain fixed in its extended state. For example, the resistance exerted by spring 33 against rotation of inner column 31 may be such that the weight of upper column alone is not sufficient to cause lower column 32a to telescope within upper column 32b such that arm 30 collapses into its fully contracted state.

Clearly, a variety of loads of different weights may be supported by arm 30 as a result (as indeed with the arms of other embodiments described herein). Spring 33 may be pre-tensioned to accommodate these different loads.

-24 -In summary, in this embodiment, the spiral tracks have been moved from the outer columns to feature on the intermediary column, whilst the bearing features are now incorporated into the outer columns. A central guide track has been included on which the intermediary column runs. The intermediary column is composed of three parts, and the spring holder and spring are fixed so that they only run vertically along the guide track. The bearing face of the intermediary spiral column is also attached to the free end of the spring and may rotate as the outer columns drive it, increasing the spring force on the spring.

This embodiment is easier to manufacture then the previously-described embodiment.

Figures 7 -8B illustrate yet a further embodiment of the present invention.

There is shown annular bearing face 48, lower column 42a, spring holder 43, inner column 41 and upper column 42b. Lower and upper columns 42a and 42b are similar to lower and upper columns 32a and 32b of the previous embodiment, except for the addition of vertical channels 47 running along a portion of the length of each column. Tubular spring holder 43 is configured to be inserted within a torsion spring (not shown). The torsion spring is the same as described in the previous embodiments. One end of the spring is fixed to annular base 43' of spring holder 43, whilst the other end of the spring is fixed to the annular base 41' of inner column 41. Spring holder 43 is received within hollow interior of inner column 41. Bearing face 48 is then positioned over the topmost end of inner column 41. Annular base 41' has a greater diameter than annular base 43'. Ball bearing rollers 46 are disposed on annular base 43' at the lower end of spring holder 43, as well as on the periphery of bearing face 48. Likewise, ball bearing rollers 49 are disposed at lower end of inner column 41 and on annular base 41'.

Lower column 42a is fit over spring holder 43 and inner column 41 such that rollers 49 of inner column 41 are received in the spiral grooves of track 44a (which in the present embodiment run counter-clockwise when looking upwards along lower column 42a). Rollers 46 of spring holder 43 are received in vertical channels 47 of lower column 42a. Upper column 42b is then fit over lower column 42a such that rollers 49 of inner column 41 are received in the spiral -25 -grooves of track 44b (which in the present embodiment run clockwise when looking upwards along upper column 42b). Bearing face 48 is then placed adjacent to annular base 41' such that rollers 46 of bearing face 48 are received in vertical channels 47 of upper column 42b.

The operation of arm 40 is similar to that which has been described in connection with the embodiments of Figure 1 -6B. In Figure SB, arm 40 is shown in an extended state. By applying a load to arm 40 in direction X, spiral track 44b engages with rollers 49 of annular base 41'. Upper column 42b is constrained to move linearly along direction X by the engagement between vertical grooves 47 and rollers 46 on bearing face 48. Rollers 46 key on the internal surface of lower column 42a to allow vertical movement of spring holder 43 without any rotation about the longitudinal axis. Because of the engagement between rollers 49 and base 41', inner column 41 is driven to rotate with respect to upper column 42b. As inner column 41 rotates, it translates linearly downwards, following track portion 44a. Rollers 46 guide base 43' of spring holder 43 down vertical channels 47 of lower column 42a. Spring holder 43 is arranged to rotate independently of inner column 41, and as a result the spring within spring holder 43 is tensioned as arm 40 contracts. Thus, as in previous embodiments, the torsion spring within holder 43 is arranged to resist rotation of inner column 41, because of its engagement with vertical channels 47 disposed on lower column 42a and its engagement with inner column 41. Rollers 46 ensure smooth movement within vertical channels 47. This provides the counterbalance to the load applied to arm 40 in direction X. When lower column 42a is telescoped fully within upper column 42b, arm 40 is in its contracted state, as shown in Figure 8A.

Another embodiment is shown in Figures 9 -1DB. In this embodiment, the vertical channels that accommodate the extension and contraction of the arm are found on inner column 51 and upper column 52b. Figures 1OA and lOB illustrate arm 50 in its contracted and extended states, respectively. A torsion spring (not shown) is disposed about spring holder 53 which is placed within inner column 51. One end of the spring is fixed to inner column 51, whilst the other end of the -26 -spring is fixed into lower bearing surface 53' (forming part of spring holder 53).

Rollers 59 on lower column 52a are arranged to engage with vertical channels 57 of inner column 51 and upper column 52b. Thus, inner column 51 and upper column 52b are constrained to translate linearly as arm 50 contracts (or extends).

Rollers 56 on upper bearing surface 58 are engaged with upper track portion 54b, whilst rollers 56 on lower bearing surface 53' are engaged with lower track portion 54a.

The operation of arm 50 is very similar to that of arm 40. Starting from an extended position (Figure lOB), a load is applied to upper column 52b in the direction of longitudinal axis X. Inner column 51 translates vertically downwards.

At the same time, upper column 52b drives upper bearing surface 58 and lower bearing surface 53' (part of spring holder 53) to rotate, by means of the engagement between rollers 56 and upper and lower track portions 54a and 54b.

Vertical channels 57 on inner column 51 and upper column 52b accommodate rollers 59 on lower column 52a, as inner column 51 rotates and translates linearly relative to lower and upper columns 52a and 52b.

Because one end of the torsion spring is fixed to lower bearing surface 53' whilst the other is fixed to inner column 51, the spring is again operable to oppose rotation (and likewise translation) of inner column 51 relative to columns 52a and 52b. This allows arm 50 to support a predetermined load.

In summary, in the above embodiment, there are two columns comprising spiral tracks: upper column 52b and lower column 52a. Upper column 52b overlaps on the outside of the assembly (for stability) and comprises guide channels 57 to ensure that upper column 52b only runs vertically relative to lower column 52a. An intermediary spring power cartridge 51 is disposed between upper and lower columns 52b and 52a to power the mechanism. Spring cartridge 51 has two bearing features: lower bearing surface 53' (that runs in the smaller diameter of lower column 52a) and upper bearing surface 58 (that runs in the larger diameter of upper column 52b). The torsion spring is fixed into both lower bearing face 53' and upper bearing face 58 of spring cartridge 51. These two bearing faces can rotate independently of each other but about the same axis.

The spiral tracks 54a and 54b are designed so that vertical movement of upper -27 -column 52b produces rotation of the lower and upper bearing surfaces 53' and 58, thereby allowing twice the amount of vertical movement for half the torque (or tension) applied to the spring.

A person skilled in the art will appreciate that the inventive concept described herein may be extended to any number of arm portion configured to allow for reciprocal rotation and translation of individual arm portions. For example, it could be possible to provide an arm having five arm portions, with each of two of the arm portions (with spiral tracks) retaining a torsion spring within their hollow interiors, and the other three arm portions configured to translate linearly as the two spring-holding arm portions rotate.

Furthermore, in each of the embodiments of Figures 5 -6B, 7 -8B and 9 -1 OB, the inner column has been described as rotating with respect to the upper and lower columns. However, as a person skilled in the art would understand, what is important is the relative movement between the arm portions. In other embodiments, it could be possible to provide an arm configured such that, when the arm contracts or extends, the inner column translates linearly along the longitudinal axis of the arm whilst the upper and lower columns are driven to rotate relative to the inner column.

Many combinations, modifications, or alterations to the features of the above embodiments will be readily apparent to the skilled person and are intended to form part of the invention. Furthermore, a person skilled in the art will recognise that any of the features described as specifically relating to one embodiment may be used in any other embodiment, by making the appropriate changes.

The second aspect of the invention seeks to provide a device (incorporating an arm) that supports a load and that may be arranged such that, when pivoting in a vertical plane about one end of the arm, the device causes the load to maintain a constant orientation with respect to the other end of the arm.

Such movement is shown in Figure 11, which shows device 100 comprising first and second support members, 110 and 120, telescoping arm 130 -28 -having inner column 140 that telescopes in and out of outer column 150. A monitor 160 is affixed to support member 120 coupled to inner column 140.

Support member 110 is coupled to outer column 150. As arm 130 rotates in a vertical plane, an orientation of monitor 160 is maintained relative to support member 110. An arc-shaped adjustment member 170 is used to adjust the orientation of monitor 160 relative to support member 110. A person skilled in the art will appreciate that other means of adjusting the monitor's orientation may be employed. As illustrated by the dashed lines, as arm 130 rotates or pivots in the vertical plane, the orientation of support member 110 relative to support member 120 is maintained constant (and, vice versa, the orientation of support member relative to support member 110 is maintained constant).

A first embodiment of this second aspect of the present invention is illustrated in Figures 12 and 13.

Device 200 comprises arm 210, and first and second support members 220 and 230. Arm 210 may be telescopic, and in the present embodiment is formed of inner shaft or column 212 disposed within outer columns or housings 214 and 216.

Arm 210 is arranged to pivot relative to first and second support members 220 and 230. Each support member is therefore pivotally joined to the ends of arm 210.

As shown in greater detail in Figure 13, each end of arm 210 is arranged to form a worm drive between inner column 212 and support members 220 and 230. Worm drive 240 comprises worm 242 engaged with worm gear 244 disposed around the periphery of inner column 212, at an end thereof.

Thus, as arm 210 rotates in the direction indicated by arrow 250, the teeth of worm 242, engaged with corresponding teeth on worm gear 244, will cause inner column 212 to rotate about its longitudinal axis. Therefore, when arm 210 rotates as indicated by arrow 250, inner column 212 will rotate as indicated by arrow 260.

A similar worm drive is disposed at the monitor-receiving end of device 200, such that, as arm 210 pivots in the direction of arrow 250, support member -29 - 230 rotates relative to arm 210, as indicated by arrow 270. The gear ratio between worm 242 and worm gear 244 may be arranged such that the orientation of support member 230 remains constant relative to support member 220 when arm 210 pivots relative to support member 220.

The housing provided by outer columns 214 and 216 allows a user to grasp arm 210 and pivot it relative to support member 220 without interfering with the internal rotation of inner column 212.

To summarise, as the angular relationship between the arm and the horizontal plane changes, a worm drive at the base of the arm causes a linking member (e.g. inner column 212) to rotate. An opposing worm gear is positioned at the head to translate the change in angle between the base of the arm and horizontal plane to the head. This preserves the angular orientation of the screen attached to the head.

A second embodiment of the second aspect of the present invention is illustrated in Figures 14 and 15. Device 300 comprises arm 310, and first and second support members 320 and 330. Arm 310 may be telescopic, and in the present embodiment is formed of inner shaft or column 312 disposed within outer housings 314 and 316.

Arm 310 is arranged to pivot relative to first and second support members 320 and 330. Each support member is therefore pivotally joined to the ends of arm 310.

Figure 15 is a magnified view of an end of arm 310 coupled to first support member 320. One or more coupling members couple first support member 320 to inner column 312. The coupling members each comprise a longitudinal portion 340 and an orthogonal portion 345. Longitudinal portion 340 is partially received within inner column 312 and is arranged to translate relative thereto, along longitudinal axis X that is defined by arm 310 as a whole. Longitudinal portion 340 is furthermore spaced from the longitudinal axis X. Orthogonal portion 345 is joined to longitudinal portion 340 at a substantially right angle. Orthogonal portion 345 is coupled to first support member 320 and may translate relative thereto in a direction parallel to pivot axis Y defined by the pivoting of arm 310 -30 -relative to first support member 320. Orthogonal portion 345 is furthermore spaced from pivot axis Y. Outer housing 316 of arm 310 is coupled to first support member 320 and is arranged to pivot about pivot axis Y, thereby allowing arm 310 as a whole to pivot about pivot axis Y relative to first support member 320.

When arm 310 pivots about pivot axis Y and relative to first support member 320 (see arrow 350), because of the off-axis spacing of orthogonal portion 345 relative to pivot axis Y, longitudinal portion 340 is constrained to rotate about longitudinal axis X. This is permitted due to orthogonal portion 345 translating back and forth parallel to pivot axis Y, during pivoting of arm 310 as a whole. As a result of the coupling of longiludinal porllon 34010 inner column 312, the rotation of longitudinal portion 340 about longitudinal axis X causes inner column 312 to rotate about its longitudinal axis X (see arrow 360).

Returning to Figure 14, at the monitor-receiving arm of 310, a similar arrangement of coupling members is found, coupling arm 310 to second support member 330. Through the same mechanism as described above, rotation of inner column 312 about its longitudinal axis X causes second support member 330 to be pivoted relative to arm 310. Therefore, pivoting of arm 310 about pivot axis Y and relative to first support member 310 causes corresponding pivoting of second support member 330 about pivot axis Y', relative to arm 310.

To summarise, there are two sets of linking members at both the head and pivot end of the arm. The linking members are disposed into an internal shaft or rod thai is free In rolale aboul us longitudinal axis. The linking members at Ihe head and pivot end are not joined together, but each have a longitudinal portion free to translate in and out of a hole disposed in the internal shaft and that is in-line with the longitudinal axis. At the other end of the arm, the linking members are fixed into the monitor-receiving head (e.g. second support member), and are allowed to move in-line with the pivot axis of the arm at the head-end. As the angular relationship between the arm and the horizontal plane changes, the linking members force the internal shaft to rotate (whilst doing so, the linking members will slide along the horizontal plane and into / out of the internal shaft).

The rotation of the support member is mirrored from the pivot end to the head -31 -end ensuring that the orientation of any item fixed to the head end-is preserved through the movement of the arm.

Figures 16A -16C illustrate a third embodiment of the second aspect of the present invention.

Device 400 is formed of similar components as those of devices 200 and 300. Device 400 additionally includes driving members 440 disposed at each end of arm 410 and coupled to support members 420 and 430.

Each driving member 440 comprises a link member 442 coupling the driver member 440 to its respective support member, 420, 430. Inner column 412 comprises a threaded groove 414 disposed along its outer surface in the longitudinal direction of arm 410, and is arranged to engage with driving portions 444 of driving members 440.

Figure 17 illustrates the movement of arm 410 relative to support member 420, driving member 444, and inner column 412. As arm 410 pivots relative to support member 420 (arrow 450), link member 442 forces driving portion 444 of drive member 440 to translate (arrow 460) along the longitudinal axis of arm 410.

Through the threaded engagement of driving portion 444 with grooved thread 414 of inner column 412, inner column 412 is caused to rotate about longitudinal axis, as indicated by arrow 470.

Similar motion is achieved at the other end of arm 410. As inner column 412 rotates about longitudinal axis, the threaded engagements of inner shaft 412 with driving portion 444 causes driving portion 444 to translate along the longitudinal axis of arm 410. Link member 442 is therefore driven forwards and, through its coupling to support member 430, causes support member 430 to pivot relative to arm 410 (vice versa, arm 410 is caused to pivot relative to support member 430).

As can be seen in Figure 16A -160, a constant orientation of support member 430 relative to support member 420 is achieved through the pivoting action of arm 410 as it pivots relative to support member 420.

To summarise, at both the pivot and head end of the arm there is a link attached to a driving mechanism. Between both the pivot and head end there is -32 -a tube with helical grooves cut into it. Each of the driving mechanisms runs in a set of helical grooves disposed at each end of the tube. As the arm rotates about the horizontal axis, the driving mechanism at the pivot end of the arm is caused to move in the grooves. This in turn causes the tube to rotate along its longitudinal axis and, the grooves being mirrored at the head end, the driving mechanism at the head end is forced along its grooves, as the arm pivots. This causes the head link to move and preserve the angle of whatever is attached to the head end throughout the movement of the arm.

In a fourth embodiment of this second aspect of the invention, an alternative driving mechanism is shown. This embodiment is very similar to the one described above. However, the driving mechanism is not drawn along the grooves cut into the tube. Rather, each driving member 540 comprises a pair of concentric rings 542 joined together by three links 544. Rotation of one ring 542 relative to another ring 542 causes the rings to move apart.

The rings 542 couple rod 512 to support members 520 and 530. Thus, as arm 510 pivots relative to first support member 520, the rings of a first driving member 540 disposed at the pivot end of arm 510 are caused to move apart and rotate relative to one another. This in turn causes rod 512 to rotate. The rotation of rod 512 causes a corresponding ring pair of a second driving member 540 at the head end of arm 510 to simultaneously rotate and move apart. Thus, in much the same way as described in relation to the previous embodiment, the angular orientation of second support member 530 relative to first support member 520 is preserved.

Figures 19A -19C show a fifth embodiment of a device for supporting a load. Device 600 comprises arm 610, and first and second support members 620 and 630. Each support member comprises a cable connection point, 620a and 630a, and arm 610 comprises at each of its ends a further cable connection point, 620b and 630b. Arm 610 is arranged to pivot, about pivot point P1, relative to first support member 620, and is furthermore arranged to pivot, about pivot point P2, relative to second support member 630. A cable 635 runs from -33 -connection point 620a to connection point 630a, passing by connection points 620b and 630b. A sheath 640 is disposed around cable 635 and is connected to connections points 620b and 630b. This produces a Bowden cable -type arrangement.

In use, starting for example from Figure 1 9A, arm 610 may pivot relative to support member 620 (as shown in figure 19A) to the position shown in Figure 19C. As arm 610 pivots relative to first support member 620, the distance separating connection point 620a from connection point 620b decreases. This is compensated by the distance separating connection point 630b from connection point 630a increasing. As shown in Figure 19B, cable 635 restrains support member 630 from pivoting freely about pivot point P2. This ensures that the orientation of support member 630 relative to support member 620 is maintained throughout the pivoting action of arm 610. As seen in Figure 19C, arm 610 has pivoted to a nearly fully upright position, and the distance separating connection point 620a from connection point 620b has nearly reached a minimum, whilst the distance separating connection point 630b from connection point 630a has correspondingly increased. Thus, orientation support member 630 has been maintained by cable 635 throughout the pivoting action of arm 610. Sheath 640 allows for the transmission of pull/push forces along cable 635, from one end of arm 610 to the other. This ensures that pivoting the change in angular relationship between arm 610 and first support member 620 is fully reciprocated at the other end of arm 610, between arm 610 and second support member 630.

As seen from Figures 19A -19C, arm 610 may be extendable such that the length of arm 610 may vary, in which case sufficient slack should be provided for cable 635 and 640 such that the Bowden cable may accommodate a wide range of arm extensions.

Figures 20A, 20B and 21 show another embodiment of a device for supporting a load. Again, as in the previously described embodiments, the device allows the load at one end of the arm to maintain a predetermined orientation relative to the other end of the arm as the arm rotates within a vertical plane. Device 700 comprises arm 710 formed of inner shaft 720 disposed within -34 -outer shaft 730. Outer shaft 730 is arranged to rotate about a longitudinal axis defined by arm 710. Each end of inner shaft 720 is coupled to a respective support member, 740, 750, such that arm 710 may pivot relative to each of support members 740 and 750. Each end of outer shaft 730 is sectioned at a non-normal angle to the longitudinal axis of arm 710, thereby forming bevelled edges at each end of outer shaft 730. In the present embodiment, the ends of outer shaft 730 are sectioned at 45° relative to the longitudinal axis. The support members 740 and 750 are pivotally coupled to the ends of inner shaft 720 such that bevelled ends 732 and 734 of outer shaft 730 are constrained to engage with support members 740 and 750.

In use, as best shown in Figure 21, arm 710 is arranged 10 pivol about support member 740. In doing so, bevelled end 732 of outer shaft 730, constrained in engagement with support member 750, cooperates with support member 750 to cause outer shaft 730 to rotate about longitudinal axis. Rotation of outer shaft 730 causes bevelled end 734 of outer shaft 730 to cooperate with support member 750 to which it is constrained in engagement. This then causes arm 710 to pivot or rotate relative to support member 750. As can be clearly seen in Figure 21, the orientation of support member 740 is kept constant relative to support member 750 throughout the entire pivoting action of arm 710.

In summary, both the pivot and head ends of the arm are separated by a pair of linking members: a inner member providing a pivot point for both the pivot and head end of the arm, and an outer member positioned on the outside of the inner member and having a 45° cul at each end Ihereof. The ouler member is constrained to rotate around the longitudinal axis of the central member with the ends both bearing on the pivots at the head and pivot end of the arm. As the second member rotates, the effect of the angled cuts is to change the angle between the pivots at the head and pivot end equally.

Figures 22A -22C and 23 show a further embodiment of a device for supporting a load.

Device 800 comprises arm 810 and a pair of support members, 820 and 830. Arm 810 is formed of shaft 812 housed within an outer casing 814. Each -35 -end of shaft 812 comprises a respective female portion 812a and 812b forming an aperture or slot within shaft 812. Each support member 820 and 830 comprises a respective male member 822 and 832, disposed to form a non-normal angle relative the longitudinal axis of arm 810. As best seen in Figure 23, each male portion 822 and 832 is received within a respective female portion 812a and 812b at an angle thereto. In the present embodiment, each male member 822 and 832 is angled at 45° relative to the longitudinal axis.

In use, arm 810 may pivot relative to support member 820. When pivoting, male member 822, angled relative to the longitudinal axis of arm 810, cooperates with female member 812a to cause arm 810 to rotate about longitudinal axis.

This in turn causes the female member 812b to cooperate with male member 832, thereby causing support member 830 to pivot relative to arm 810. Thus, as arm 810 rotates or pivots in a vertical plane, support member 830 (used to support, for example, a monitor) maintains a constant orientation relative to support member 820.

To summarise, the head and pivot joints are separated by a central linking member. The linking member has a slot cut into it at either end. On outer support member also runs between the head and pivot end and is located on a principal axle at both the head and pivot end allowing the arm to pivot up and down. Another axle is fitted at both the pivot and head end and is positioned at 452 to the principal axle. The slots on the linking member bear onto this axle. As the arm is lowered, changing the angular relationship between the arm and the horizontal plane, the 452 axle causes the linking member to rotate. This rotation is translated by the 452 axle at the head end which in turn causes the angle of the head to change. These relationships ensure that the change in angular relationship at the pivot joint is mirrored at the head end to.

Many combinations, modifications, or alterations to the features of the above embodiments will be readily apparent to the skilled person and are intended to form part of the invention. Furthermore, a person skilled in the art will recognise that any of the features described as specifically relating to one -36 -embodiment may be used in any other embodiment, by making the appropriate changes.

Claims

-37 -CLAIMS1. A telescopic arm for supporting a load, the arm defining a longitudinal axis and comprising: a first arm portion; and a second arm portion, wherein the telescopic arm is arranged to contract and/or extend along the longitudinal axis by one of the arm portions moving linearly relative to the other arm portion, and wherein the first and second arm portions are engaged one with the other such that linear motion of the first arm portion relative to the second arm portion causes rotation of the second arm portion about the longitudinal axis relative to the first arm portion, and such that rotation of first arm portion about the longitudinal axis relative to the second arm portion causes linear motion of the second arm portion relative to the first arm portion, and wherein the telescopic arm further comprises a resilient bias arranged to resist rotation of the first arm portion about the longitudinal axis relative to the second arm portion.
2. The telescopic arm of claim 1, wherein the resilient bias comprises a torsion spring.
3. The telescopic arm of claim 1 or 2, wherein a resilience of the resilient bias is preset so as to prevent contraction of the telescopic arm when a predetermined load is applied to the telescopic arm along the longitudinal axis.
4. The telescopic arm of any preceding claim, wherein at least a portion of the first arm portion comprises a spiral track disposed along the longitudinal axis, and wherein the second arm portion is arranged to engage with the spiral track when moving along the longitudinal axis relative to the first arm portion.
5. The telescopic arm of claim 4, wherein a pitch of the spiral track, relative to the longitudinal axis, varies along the longitudinal axis.

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6. The telescopic arm of any preceding claim, wherein an end of the resilient bias is positionally fixed in relation to one of the arm portions.
7. The telescopic arm of any preceding claim, wherein the engagement of the first arm portion with the second arm portion is arranged to generate a friction force on the first and second arm portions that resists movement of the first arm portion along the longitudinal axis relative to the second arm portion.
8. The telescopic arm of claim 7, wherein the friction force counterbalances a force exerted by the resilient bias on the first and second arm portions so as to prevent movement of the first arm portion along the longitudinal axis relative to the second arm portion when a load below a predetermined threshold is applied to the telescopic arm in the longitudinal direction.
9. The telescopic arm of claim 8 when dependent on claim 4 or 5, wherein a magnitude of the friction force is at least partially determined by a pitch of the spiral track and/or a resilience of the resilient bias.
10. The telescopic arm of any preceding claim, further comprising a third arm portion, wherein the telescopic arm is further arranged to contract and/or extend along the longitudinal axis by one of the first, second or third arm portions moving linearly relative to the other arm portions, and wherein the second and third arm portions are engaged one with the other such that linear motion of the second arm portion relative to the third arm portion causes rotation of the third arm portion about the longitudinal axis relative to the second arm portion, and such that rotation of the second arm portion about the longitudinal axis relative to the third arm portion causes linear motion of the third arm portion relative to the second arm portion.
11. The telescopic arm of claim 10, wherein the resilient bias is further arranged to resist rotation of at least one of the first, second and third arm portions about the longitudinal axis.

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12. The telescopic arm of claim 10 or 11, wherein at least a portion of the first arm portion comprises a spiral track disposed along the longitudinal axis, and wherein the second and third arm portions are each arranged to engage with the spiral track when moving along the longitudinal axis relative to the first arm portion.
13. The telescopic arm of claim 12, wherein the spiral track comprises first and second track portions, each track portion running in a different rotational direction to the other track portion.
14. The telescopic arm of claim 10 or 11, wherein at least a respective portion of each of the second and third arm portions comprises a spiral track disposed along the longitudinal axis, and wherein the first arm portion is arranged to engage with each of the spiral tracks disposed on the second and third arm portions when moving along the longitudinal axis relative to the second and third arm portions.
15. The telescopic arm of any preceding claim, wherein the first arm portion is arranged to house the resilient bias.
16. The telescopic arm of any preceding claim, wherein the resilient bias is further arranged to move with the first arm portion when the first arm portion moves along the longitudinal axis relative to the second arm portion.
17. The telescopic arm of any of claims 10-16, wherein the first arm portion comprises an inner arm portion and an outer arm portion, the inner and outer arm portions being rotatable relative to each other about the longitudinal axis.
18. The telescopic arm of claim 17, wherein one end of the resilient bias is coupled to the inner arm portion, and wherein the other end of the resilient bias is coupled to the outer arm portion.

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19. The telescopic arm of any preceding claim, wherein the resilient bias is disposed at least partially within each of the first and second arm portions.
20. The telescopic arm of any of claims 4, 5 and 12-14, wherein at least one of the arms portions comprises rollers for guiding the at least one of the arm portions along at least one of the spiral tracks.
21. A device for supporting a load, comprising: an arm having first and second ends, and defining a longitudinal axis, each of the first and second ends comprising a bearing surface or edge; and first and second support members, each support member being constrained in engagement with a respective bearing surface or edge of the arm, wherein the arm is arranged to pivot at the first end and relative to the first support member such that the first support member cooperates with the first bearing surface or edge to cause the arm to rotate about the longitudinal axis, thereby causing the second bearing surface or edge to cooperate with the second support member to cause the arm to pivot at the second end and relative to the second support member.
22. The device of claim 21, wherein each of the first and second ends is sectioned at a non-normal angle to the longitudinal axis, and wherein the arm is further arranged to pivot at the first end and relative to the first support member such that the first sectioned end cooperates with the first support member to cause the arm to rotate about the longitudinal axis, thereby causing the second sectioned end to cooperate with the second support member to cause the arm to pivot at the second end and relative to the second support member.
23. The device of claim 22, wherein each end of the arm is sectioned at an angle of 45° relative to the longitudinal axis. -41 -
24. The device of any of claims 21 -23, wherein the first support member is arranged to attach the device to a fixed platform.
25. The device of any of claims 21 -24, wherein the second support member is arranged to receive a load to be supported by the device.
26. The device of any of claims 21 -25, wherein the device is arranged such that, when the arm pivots at the first end and relative to the first support member, an orientation of the first support member relative to the second support member is maintained.
27. The device of claim 21, wherein each support member comprises a male member constrained in engagement with a respective bearing surface of the arm, wherein the arm is arranged to pivot at the first end and relative to the first support member such that the first male member cooperates with the first bearing surface to cause the arm to rotate about the longitudinal axis, thereby causing the second bearing surface to cooperate with the second male member to cause the arm to pivot at the second end and relative to the second support member.
28. The device of claim 27, wherein each end of the arm further comprises an additional bearing surface such that each end of the arm comprises a pair of bearing surfaces spaced one from the other, thereby forming at each end of the arm a female portion for receiving therein a respective male member.
29. The device of claim 28, wherein each male member is cylindrical, and wherein each pair of spaced bearing surfaces forms an opening having a size equal to the diameter of the respective male member received within the female portion.
30. The device of claim 28 or 29, wherein each female portion comprises a slot extending through the arm.

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31. The device of any of claims 28 -30, wherein each male member comprises a rod extending through a respective female portion of the arm.
32. The device of any of claims 27 -31, wherein each male member is fixed relative to its respective support member.
33. The device of any of claims 27 -32, wherein each male member extends at a non-normal angle relative to the longitudinal axis.
34. The device of claim 33, wherein each male member extends at an angle of 45° relative to the longitudinal axis.
35. The device of any of claims 27 -34, wherein the first support member is arranged to attach the device to a fixed platform.
36. The device of any of claims 27 -35, wherein the second support member is arranged to receive a load to be supported by the device.
37. The device of any of claims 27 -36, wherein the device is arranged such that, when the arm pivots at the first end and relative to the first support member, an orientation of the first support member relative to the second support member is maintained.
38. A device for supporting a load, comprising: an arm having first and second ends; first and second support members coupled to the first and second ends at first and second pivoting points, the arm being arranged to pivot about each of the first and second pivoting points and relative to each of the first and second support members, wherein each of the first and second support members comprises an attachment point spaced from its respective pivoting point; and a linking member connecting the first and second support members via the first and second attachment points, such that the linking member imparts -43 -movement of the first support member pivoting relative to the arm to the second support member causing the second support member to pivot relative to the arm.
39. The device of claim 38, wherein the device further comprises a sheath arranged about the linking member.
40. The device of claim 39, wherein the linking member is a Bowden cable.
41. The device of any of claims 38 -40, further comprising a pair of guide points for guiding the linking member therethrough.
42. The device of claim 41 when dependent on claim 39 or 40, wherein the sheath is attached between the pair of guide points.
43. The device of any of claims 38 -42, wherein the linking member is one of: a cable, a string, a cord, and a wire.
44. The device of any of claims 38 -43, wherein the first support member is arranged to attach the device to a fixed platform.
45. The device of any of claims 38 -44, wherein the second support member is arranged to receive a load to be supported by the device.
46. The device of any of claims 38 -45, wherein the device is arranged such that, when the arm pivots at the first end and relative to the first support member, an orientation of the first support member relative to the second support member is maintained.
47. A device for supporting a load, comprising: an arm having first and second ends, and a rod, the arm defining a longitudinal axis; -44 -first and second support members coupled to the first and second ends of the arm; and first and second driving members engaged with the rod, each driving member being coupled to a respective support member at a pivoting point located off the longitudinal axis, wherein the arm is arranged to pivot about the first end and relative to the first support member such that the first driving member pivots relative to the first support member about the first pivoting point so that the engagement of the first driving member with the rod causes the rod to rotate about the longitudinal axis, thereby causing the second driving member to pivot relative to the second support member about the second pivoting point, such that the arm pivots at the second end and relative to the second support member.
48. The device of claim 47, wherein the arm further comprises a restraining mechanism arranged such that the rod is constrained longitudinally within the arm.
49. The device of claim 47 or 48, wherein the rod is threaded, and wherein each driving member comprises an internal thread arranged around the threaded rod.
50. The device of claim 49, wherein the arm is further arranged such that, when the first driving member pivots relative to the first support member, the first driving member is drawn along the longitudinal axis and translates relative to the threaded rod, and wherein, when the threaded rod rotates about the longitudinal axis, the second driving member is drawn along the longitudinal axis and translates relative to the threaded rod.
51. The device of claim 49 or 50, wherein each driving member comprises a driving portion in engagement with the threaded rod, and a link member coupling each driving portion to its respective support member at its respective pivoting point.

-45 -
52. The device of any of claims 47 -51, wherein the first and second support members are coupled to the first and second ends of the arm at points located on the longitudinal axis.
53. The device of any of claims 47 -52, wherein the device is arranged such that, when the arm pivots at the first end and relative to the first support member, an orientation of the second support member relative to the first support member is maintained.
54. The device of any of claims 47 -53, wherein the first support member is arranged to attach the device to a fixed platform.
55. The device of any of claims 47 -54, wherein the second support member is arranged to receive a load to be supported by the device.
56. A device for supporting a load, comprising: first and second support members; an arm defining a longitudinal axis and being arranged to pivot relative to each of the first and second support members about a respective pivot axis; one or more first coupling members coupling the first support member to the arm; and one or more second coupling members coupling the second support member to the arm, wherein: each coupling member comprises a longitudinal portion disposed substantially parallel to the longitudinal axis, and an orthogonal portion disposed substantially parallel to the pivot axes, each longitudinal portion being rotatable about the longitudinal axis, and each orthogonal portion being spaced from its respective pivot axis; and the arm is arranged such that, when pivoting about the first pivot axis and relative to the first support member, the first coupling member cooperates with the first support member and the arm to cause the arm to rotate about the -46 -longitudinal axis, thereby causing the arm to cooperate with the second coupling member so as to cause the arm to pivot about the second pivot axis and relative to the second support member.
57. The device of claim 56, wherein the device is arranged such that, when the arm pivots at the first end and relative to the first support member, an orientation of the second support member relative to the first support member is maintained.
58. The device of claim 56 or 57, wherein the first support member is arranged to attach the device to a fixed platform.
59. The device of any of claims 56 -58, wherein the second support member is arranged to receive a load to be supported by the device.
60. The device of any of claims 56 -59, wherein each orthogonal portion is arranged to translate relative to its respective support member and parallel to its respective pivot axis during pivoting of the arm.
61. The device of any of claims 56 -60, wherein each longitudinal portion is arranged to translate relative to the arm and parallel to the longitudinal axis during pivoting of the arm.
62. The device of any of claims 56 -61, wherein the device comprises a pair of first and a pair of second coupling members, wherein each pair of longitudinal portions of the first and second coupling member is disposed within the arm on opposite sides of the longitudinal axis
63. A device for supporting a load, comprising: an arm having first and second ends, and defining a longitudinal axis; first and second support members; and -47 -first and second worm drives coupling each end of the arm to a respective support member, wherein the arm is arranged to pivot at the first end and relative to the first support member such that the first worm drive operates to cause the arm to rotate about the longitudinal axis, thereby operating the second worm drive to cause the arm to pivot at the second end and relative to the second support member.
64. The device of claim 63, wherein each support member comprises a worm arranged to engage with a worm gear, thereby forming a respective one of the worm drives.
65. The device of claim 63 or 64, wherein each end of the arm comprises a worm gear arranged to engage with a worm, thereby forming a respective one of the worm drives.
66. The device of claim 64 or 65, wherein each worm gear is disposed around a periphery of the arm.
67. The device of any of claims 63 -66, wherein the first support member is arranged to attach the device to a fixed platform.
68. The device of any of claims 63 -67, wherein the second support member is arranged to receive a load to be supported by the device.
69. The device of any of claims 63 -68, wherein the gear ratio of each of the worm drives is arranged such that, when the arm pivots at the first end and relative to the first support member, an orientation of the second support member relative to the first support member is maintained.