WO2011072325A1

WO2011072325A1 - Length adjustment mechanism for a pole

Info

Publication number: WO2011072325A1
Application number: PCT/AU2010/001680
Authority: WO
Inventors: Andrew Crawford; Mathew Trainor; Kenji Eu
Original assignee: Tricycle Developments Pty Ltd
Priority date: 2009-12-14
Filing date: 2010-12-13
Publication date: 2011-06-23

Abstract

A mechanism including a ramp member (3) with first and second tapered walls (13, 14); first and second plurality of balls (4, 18) arranged to frictionally engage between outer tube (1) and ramp member (3) in an engaged position. A release mechanism having a release member (10) located between the first and second plurality of balls; a control collar (16) connected to the release member. Movement of the control collar in a first direction causes the release member to contact the first balls and moves the balls into a first disengaged position, allowing movement of the inner tube in said first direction, but not in a second direction opposite the first direction; movement of the control collar in the second direction similarly allows movement of the inner tube in the second direction, but not in the first direction.

Description

Length adjustment mechanism for a pole

Field of the invention

The present invention relates to a length adjustment mechanism for telescoping poles. The invention finds particular application for telescoping poles for use in the intravenous administration of fluids.

Background of the invention

Telescoping intravenous poles, or IV poles, are commonly used in hospitals for holding a container of IV fluid suspended above a patient. Such poles usually include an inner tube or rod which is longitudinally movable relative to an outer tube and which may be extended to the required height and then locked in place.

The prior art IV poles have a range of locking mechanisms which allow the heights to be adjusted to the desired height and then locked into position. The issue encountered with these poles is that adjustment requires the user to hold the upper part of the IV pole while releasing the locking mechanism with the other hand. This process requires the use of two hands which is inconvenient and sometimes unsafe for the user. It may require the IV bag to be placed on a nearby surface, which could result in contamination. There is a need for a locking mechanism that the user can unlock, adjust the height of the IV pole and lock with the use of only one hand.

Some prior art IV poles address this problem, but the mechanism in these poles fully releases the pole to move in both directions when unlocked. If the pole is in use and heavily loaded then this release can cause the pole to rapidly slide down and hit the user from above.

The intention of this invention is to create a height adjustment mechanism for an IV pole which is operable with only one hand.

Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in Australia or any other jurisdiction or that this prior art could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art. Summary of the invention

According to a first aspect of the present invention there is provided a mechanism for a length adjustable pole having an outer tube and an inner tuber slidable within the outer tube, the mechanism including:

a locking mechanism connected to an end of the inner tube and eatable within the outer tube, having:

a ramp member comprising a central portion with first and second tapered walls extending therefrom concentrically to a central axis of the outer and inner tubes;

first and second plurality of balls arranged in an array around the first and second walls to frictionally engage between the inner surface of the outer tube and the tapered walls of the ramp member in an engaged position;

a release mechanism, having: a release member located concentrically to the ramp member between the first and second plurality of balls;

a control member accessible from the outside of the inner tube and connected to the release member;

wherein movement of the control member in a first direction with respect to the ramp member causes the release member to contact the first plurality of balls and moves the balls into a first disengaged position reducing the first balls frictional engagement with the first tapered wall and/or the wall of the outer tube, allowing movement of the inner tube in said first direction, but not in a second direction opposite the first direction; and

wherein movement of the control member in said second direction with respect to the ramp member causes the release member to contact the second plurality of balls and moves the balls into a second disengaged position reducing the second balls frictional engagement with the second tapered wall and/or the wall of the outer tube, allowing movement of the inner tube in said second direction, but not in said first direction.

According to a second aspect of the present invention there is provided a length adjustable pole, including: an outer tube and an inner tuber slidable within the outer tube; an adjustment mechanism including: a locking mechanism connected to an end of the inner tube and locatable within the outer tube, having:

Advantageously, where the pole is oriented vertically, the first direction is upwards and the second direction is downwards. Preferably the first and second pluralities of balls are rings of abutting balls around the interior of the outer tube. The balls are preferably held within retainers that do not impede on the frictional engagement of the balls.

A first spring is preferably provided to hold the first plurality of balls in a downward engagement. A second spring is preferably provided to hold the second plurality of balls in an upward engagement, preventing movement of the tubes without movement of the release mechanism. Respective retainer members preferably hold the springs in a compression condition.

The control member may be spaced from the release member by a translation member. The control member therefore may be positioned around the outside of the inner member at a height convenient for the user.

The ramp member preferably includes a slot through its central axis for receiving an end of the translation member. This allows a direct connection between the translation member and the release member.

The ramp member is preferably rigidly connected to the inner tuber, preferably by a connection nut at the lower end of the inner tube.

The angle of the tapered walls is preferably in the range of 8-20 degrees.

Advantageously, the release mechanism includes a control member guide having a slot extending in the axial direction of the inner tube. Preferably the control member guide is rigidly attached to the inner tube. The inner tube may have a corresponding slot aligned with the slot of the control member guide. In this embodiment the control member has a pin connection to the translation member through the aligned slots, such that the control member can move with respect to the control member guide along the slots.

In a preferred embodiment, the pole of the present invention is vertically oriented for use as an IV pole and includes a lower tube which may be mounted in stationary relationship to a support member such as may be provided on a hospital bed or wheeled base. An upper tube having means for supporting an IV container is located concentrically to the lower tube and may be adjusted longitudinally relative to the lower tube. The locking mechanism is included to allow a user to control this adjustment and prevent unintentional adjustment. According to an embodiment of the invention, the ramp member is attached to the lower end of the upper tube. The ramp member features a first tapered wall orientated concentrically to the central axis of the upper rod or tube. This tapered wall contacts a first plurality of balls arranged in an array around the ramp member. This plurality of balls also contacts the lower support tube wall such that it is contacted by balls from a multitude of directions around the central axis of the lower tube. Given this configuration as the upper rod or tube is adjusted longitudinally relative to the lower tube the balls move in contact with the tapered wall of the ramp member. The angle and diameter of the tapered wall on the ramp member are such that as the upper rod or tube is adjusted longitudinally relative to the lower tube in one direction friction holds the balls in contact with the wall of the lower tube resisting the adjustment in this direction called the first locking direction. The angle and diameter of the tapered wall on the ramp member are also such that as the upper rod or tube is adjusted longitudinally relative to the lower tube in the opposing direction the balls reduce contact with the wall of the lower tube allowing the upper rod or tube to be adjusted in this direction, called the first free direction.

In this embodiment the ramp member also features a second tapered wall which is also orientated concentrically to the central axis of the upper rod or tube. This second tapered wall contacts a second plurality of balls arranged in an array around the ramp member. This second plurality of balls also contacts the lower tube wall such that it is contacted by balls from a multitude of directions around the central axis of the lower tube. Given this configuration as the upper rod or tube is adjusted longitudinally relative to the lower tube the second plurality balls move in contact with the second tapered wall of the ramp member. The angle and diameter of the second tapered wall on the ramp member are such that as the upper rod or tube is adjusted longitudinally relative to the lower tube in one direction friction holds the second plurality of balls in contact with the wall of the lower tube resisting the adjustment in this direction, called the second locking direction. The angle and diameter of the second tapered wall on the ramp member are also such that as the upper rod or tube is adjusted longitudinally relative to the lower tube in the opposing direction the second plurality of balls reduce contact with the wall of the lower tube allowing the upper rod or tube to be adjusted in this direction, called the second free direction. The angle of the second tapered wall on the ramp member is such that the second locking direction is in the opposite direction to the first locking direction.

When this assembly is orientated with the central axis vertically, as is common in its application, one plurality of balls will be inclined to fall under gravity losing contact with the ramp member. To prevent this, the first plurality of balls are preferably held in contact with the ramp member and the lower tube using a spring member supported by a retaining member. For reliability the second plurality of balls may also be held in contact with the ramp member and the lower tube by a second spring member supported by a second retaining member.

This configuration ensures that the ramp member and the connected upper rod or tube is resisted from adjusting longitudinally relative to the lower tube in one direction by the friction of one plurality of balls contacting the ramp member and the lower tube and in the other direction by the friction of the second plurality of balls contacting the ramp member and lower tube.

To allow the upper rod or tube and ramp member assembly to be adjusted longitudinally relative to the lower tube the release mechanism also includes a release member. The release member is positioned concentrically to the ramp member and lower tube and is positioned between the first plurality of balls and the second plurality of balls. The release member has dimensions such that when it is adjusted longitudinally relative to the ramp member in one direction it will come into contact with the first plurality of balls and adjust the position of these balls such that they reduce contact with the wall of the lower tube or ramp member allowing the upper rod or tube and ramp member assembly to be adjusted in this direction. The release member also has dimensions such that when it is adjusted longitudinally relative to the ramp member in the opposing direction it will come into contact with the second plurality of balls and adjust the position of these balls such that they reduce contact with the wall of the lower tube or ramp member allowing the upper rod or tube and ramp member assembly to be adjusted in this opposing direction.

To allow adjustment of the release member it is preferably connected to a translation member. This connection may be via a rigid or pivoting connection and may require a release connection member. Preferably the translation member is of a dimension to allow the control member to be position some distance away from the locking mechanism.

The control member is preferably positioned on or around the inner tube. The control member is connected to the inner tube such that it is free to be adjusted longitudinally in relation to the inner tube. The control member is also connected to the translation member with a connection that may be rigid or a pivoting connection and may require a control connection member. This connection is such that when the control member is adjusted longitudinally in relation to the inner tube then the translation member is also proportionally adjusted. The effect of the translation member and its connections is that adjustment of the control member effects proportional adjustment of the release member.

An optional feature of this invention is to include a spring member or counter-weight member attached between the ramp member or upper tube and the lower support tube. The dimensions of the spring member or counter-weight member are such that it does not interfere with the adjustment of the upper rod or tube except to provide force upwards. The dimension of said spring or counter-weight member may be such that it provides force across the range of adjustment of the upper rod or tube.

Brief description of the drawings

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG.1 - is an side view of the length adjustable pole of the present invention with the lower portion thereof shown in partial cross section;

FIG.2 - is a cross sectional view of the locking mechanism; and

FIG.3 - is a cross sectional view of the release mechanism.

Detailed description of the embodiments

In this preferred embodiment of the invention the outer or lower tube (1 ) and the inner or upper tube (2) are constructed from stainless steel but could also be steel, aluminium or plastic tubes or rods. These tubes are different sizes with the lower tube (1) being larger than the upper tube (2) such that the upper tube can adjust longitudinally inside the lower tube (2) by sliding within it (best shown in Figure 1 ). In this embodiment the upper tube (2) also has a bent metal hook portion (25) at its upper end, which serves to hold securely a single or plurality of intravenous fluids containers (not shown). This bent metal hook portion (25) is also stainless steel in the embodiment to allow for easy fabrication to the tube, but could also be steel, aluminium or plastic and attached by different means such as snap fit, interference fit or fastener.

The locking mechanism (30) in this embodiment comprises a ramp member (3), an upper ring of balls (4), an upper ball retainer (5), an upper spring (6), an upper spring retainer (7), a lower ring of balls (18) , a lower ball retainer (19), a lower spring (20), a lower spring retainer (21), a release member or collar (8), a release pin (9), a translation member (10), a connection nut (11), a bottom stopper (12) (Figure 2), a control member guide (15), a control member (16) and a control pin (17) (Figure 3).

In this embodiment of the invention the ramp member (3) is a turned steel component but could also be constructed from stainless steel, aluminium or plastic. The ramp member (3) includes a first tapered outer face (13) which is of larger diameter at its lower end and which contacts the first ring of balls (4) and a second tapered outer face (14) below the first which tapers such that it is of larger diameter at its upper end and which contacts the second ring of balls (18). In this embodiment the angle of the tapered faces (13, 14) of the ramp member (3) is between 8-20 degrees and causes the balls to have sufficient friction to maintain contact with ramp member (3) and the lower support tube (1) to resist adjustment of the upper tube (2). In this embodiment these two tapered faces (13, 14) are concentric to the central axis of the ramp member (3) and are at a distance that when the first and second ball rings (5 & 18) are in contact with the lower support tube (10) allow the release collar (8) to be located between the rings of balls. In this embodiment the first and second rings of balls consist of more than two equally sized steel balls, but could also be stainless steel, plastic or rubber and of differing sizes within each ring or differing sizes between the rings. For ease of assembly and consistency of function each ring of balls is retained within a ball retainer (5, 19), this retainer is constructed of low friction plastic but could also be constructed from steel, stainless steel or plastic. To prevent the second ring of balls from falling out of contact with the second tapered wall under gravity a lower spring (20) provides upward force on the balls and to improve the consistency of performance of the first ring of balls (4) an upper spring (6) provides downwards force on the balls. The upper and lower springs (6, 20) are positioned concentrically to the axis of the ramp member (3) and are held in a compressed position by the upper spring retainer (7) and lower spring retainer (21) respectively and are constructed from spring steel as compression springs 5 but could also be stainless steel as a compression spring or plastic or elastomer as a compression ring.

In this embodiment the ramp member (3) also has a vertically orientated slot (32) which passes horizontally through the member (3) and a concentric hole (34) vertically through the member (3). The vertical hole (34) allows the release member (10) to pass into the 10 ramp member (3) and be connected to the release pin (9). The release pin (9) is connected to the release collar (8) on two sides and passes through the slot in the ramp member within which it is connected with a pivoting connection to the translation member (10).

This pin connection is such that when the translation member (10) is adjusted I S longitudinally in relation to the ramp member (3) the release collar (8) is adjusted equally in relationship to the ramp member (3). It is a critical feature of this embodiment that the dimensional height of the release collar (8) is such that when it is adjusted longitudinally in relation to the ramp member in one direction that it comes into contact with, and dislodges the first ring of balls from contact with the first tapered outer face 0 (13) of the ramp member before the release pin reaches the end of the slot (32) in the ramp member (3) and that when it is adjusted longitudinally in relation to the ramp member in the opposing direction that it comes into contact with, and dislodges the second ring of balls from contact with the second tapered outer face (14) of the ramp member before the release pin reaches the other end of the slot in the ramp member 5 (3). In this embodiment the release collar, release member and release pin are constructed from steel but could also be constructed from stainless steel, aluminium or plastic.

In this embodiment the ramp member is attached to a connection nut (11) which is rigidly attached to the lower end of the upper tube (2). In an alternative embodiment the 0 ramp member is attached directly to the upper tube (2) or attached to the connection nut (11 ) which is attached to the upper tube (2). When constructed as described this embodiment of the invention allows:

the ramp member (3) to be prevented from adjustment in either direction longitudinally by friction from contact of the first (4) and second rings of balls (18) with both the lower tube (1) and the ramp member (3) when the translation member (10) is adjusted to its central position;

the ramp member (3) to be adjusted in an upward direction but not a downward direction longitudinally by friction from contact of the second ring of balls (18) with both the lower tube (1) and the ramp member (3) and the release of contact on the ramp member (1) of the first ring of balls by the release collar (8) when the translation member (10) is adjusted to its upper position;

the ramp member (3) to be adjusted in an downward direction but not a upwards direction longitudinally by friction from contact of the first rings of balls (4) with both the lower tube (1 )and the ramp member (3) and the release of contact on the ramp member (3) of the second ring of balls (18) by the release collar (8) when the translation member (10) is adjusted to its lower position.

In this embodiment the user is given control of the locking mechanism with a control mechanism (36) which consists of a control member guide (15) which features a vertically aligned slot (38) in its outer wall on two sides and an upper lip (40) and a lower lip (42) and is attached rigidly to the upper tube (2). The upper tube (2) has a vertically aligned slot (42) cut horizontally through both walls of the tube and the control member guide is aligned such that the slots in its outer wall and the slots of the upper tube are aligned. The control member (16) is positioned concentrically around the control member guide (15) and dimensioned such that it can be adjusted longitudinally in relation to the control member guide (15) and the upper tube (2) within the vertical limits of the upper lip (40) and lower lip (42) of the control member guide (15). The control member (16) is connected via the control pin (17) through the aligned slots (38, 44) in the upper tube (2) and control member guide (15) to the translation member (10) such that when the control member (16) is adjusted longitudinally the locking mechanism (30) is adjusted equally. The combined function of the control mechanism (36) and the locking mechanism (30) in this embodiment is such that:

as the control member (16) is adjusted longitudinally upwards, by the user, the release collar (8) is adjusted proportionately upwards. Thus releasing the first ring of balls(4) from contact with the first tapered wall (13) of the ramp member (3) and thereby allowing the upper tube (2) to be adjusted freely upwards longitudinally in relation to the lower tube (1). While leaving the second ring of balls (18) in contact with the second tapered wall (14) of the ramp member(3) and the lower tube (1 ). This prevents downward adjustment of the upper tube (2) in relation to the lower tube (1 ).

as the control member (16) is adjusted longitudinally downwards, by the user, the release collar (8) is adjusted proportionately downwards. Thus releasing the second ring of balls (18) from contact with the second tapered wall (14) of the ramp member (3) and thereby allowing the upper tube (2) to be adjusted freely downwards longitudinally in relation to the lower tube (1). While leaving the first ring of balls (4) in contact with the first tapered wall (13) of the ramp member (3) and the lower tube (1). This prevents upwards adjustment of the upper tube (2) in relation to the lower tube (1 ),

as the control member(16) is not adjusted, longitudinally the upper (6) and lower springs (20) to return the release collar (8) to a central position in which the first ring of balls (4) is in contact with the first tapered wall (13) of the ramp member(3) and the lower tube (1 ) and the second set of balls (18) is in contact with the second tapered wall (14) of the ramp member (3) and the lower tube (1) and as such the upper tube (2) is prevented from adjusting in relation to the lower tube in either direction.

In this respect it is the preferred embodiment of the invention that the user adjusts the control towards the direction that the mechanism allows the IV pole to be adjusted. Alternative embodiments would allow the user to adjust the control in the opposing, a perpendicular or and obtuse angle to the allowed adjustment direction of the IV pole.

This embodiment can also feature a bottom stop (12) which reduces the range of adjustment for the ramp member and upper tube and thereby provides the benefit of preventing the control member guide (15) from contacting the lower tube cap (26). This prevents damage to the control mechanism and the jamming of the users fingers. An optional feature is the inclusion of a load spring member attached between the ramp member or upper tube and the lower support tube. This spring applies a force between the lower support tube and the upper tube in the opposite direction to gravity acting on the upper tube and in this embodiment the load spring applies a force of a proportion of the sum of the weight of the upper tube, the locking and control mechanisms and two containers of intravenous fluids. In the preferred embodiment this proportion is 80%, but in alternative embodiments this proportion may be different. In this embodiment the spring is of such dimension and construction that it has a low (less than 20%) variation in the force it applies between the upper tube and the lower support tube as the upper tube is adjusted through its range of adjustment longitudinally in relation to the lower tube. In the preferred embodiment the load spring is a compression gas spring, but in an alternative embodiment the load spring is a compression spring or a tension spring constructed from steel or stainless steel or elastomer or rubber compound.

The effect of the inclusion of this optional feature in the preferred embodiment is to reduce the force the user needs apply to adjust the height of the IV pole when it is heavily loaded with fluid containers.

An alternative embodiment (not shown) of the control mechanism consists of the control member, the upper tube, the release member and the control pin. The upper tube of this alternative embodiment has a vertically aligned slot cut horizontally through both walls of the tube. In this alternative embodiment the control member is positioned concentrically around upper tube. The control member is connected via the control pin through the aligned slots in the upper tube to the release member such that when the control member is adjusted longitudinally the release member is adjusted equally. In this alternative embodiment the dimension of the vertical slot in the wall of the upper tube is such that the control pin may be adjusted vertically without excess friction on the slot walls and allowed a greater range of longitudinal adjustment than that allowed to the release collar in the locking mechanism.

In an alternative embodiment of this invention the lower support tube is of smaller diameter than the upper tube, or the locking mechanism and control mechanisms are attached to the lower member rather than to the upper member and the first and second rings of balls contact the wall of the upper tube rather than the wall of the lower support tube. The illustrations, photographs and drawings, if any, form part of the disclosure of this specification as does the description, illustrations, photographs and drawings of any associated provisional or parent specification or of any priority document, if any, all of which are imported hereinto as part of the record hereof.

Finally it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements or parts without departing from the spirit and ambit of the invention.

Claims

1. A mechanism for a length adjustable pole having an outer tube and an inner tuber slidable within the outer tube, the mechanism including: a locking mechanism connected to an end of the inner tube and beatable within the outer tube, having:

a ramp member comprising a central portion with first and second tapered walls extending therefrom concentrically to a central axis of the outer and inner tubes; first and second plurality of balls arranged in an array around the first and second walls to frictionally engage between the inner surface of the outer tube and the tapered walls of the ramp member in an engaged position;

wherein movement of the control member in a first direction with respect to the ramp member causes the release member to contact the first plurality of balls and moves the balls into a first disengaged position reducing the first balls factional engagement with the first tapered wall and/or the wall of the outer tube, allowing movement of the inner tube in said first direction, but not in a second direction opposite the first direction; and

2. A mechanism according to claim 1 , wherein, when the pole is oriented vertically, the first direction is upwards and the second direction is downwards.

3. A mechanism according to claim 1 or 2, wherein the first and second pluralities of balls are rings of abutting balls around the interior of the outer tube.

4. A mechanism according to claim 3, wherein the balls are held within retainers that do not impede on the frictional engagement of the balls.

5. A mechanism according to any one of the preceding claims, wherein a first spring is provided to hold one of the pluralities of balls in a respective upward or downward engagement.

6. A mechanism according to claim 5, wherein a second spring is provided to hold the second plurality of balls in a respective upward or downward engagement

7. A mechanism according to claim 5 or 6, wherein the spring(s) prevent movement of the tubes without movement of the release mechanism.

8. A mechanism according to claim 5, 6 or 7, wherein respective retainer members hold the springs in a compression condition.

9. A mechanism according to any one of the preceding claims, wherein the control member is spaced from the release member by a translation member.

10. A mechanism according to claim 9, wherein the control member is positioned around the outside of the inner member at a height convenient for the user.

11. A mechanism according to claim 9 or 10, wherein the ramp member includes a slot through its central axis for receiving an end of the translation member..

12. A mechanism according to claim 11 , wherein there is a direct connection between the translation member and the release member.

13. A mechanism according to any one of the preceding claims, wherein the ramp member is rigidly connected to the inner tuber.

14. A mechanism according to any one of the preceding claims, wherein the angle of the tapered walls is in the range of 8-20 degrees.

15. A mechanism according to any one of the preceding claims, wherein the release mechanism includes a control member guide having a slot extending in the axial direction of the inner tube.

16. A mechanism according to claim 15, wherein the control member guide is rigidly attached to the inner tube.

17. A mechanism according to claim 16, wherein the inner tube has a corresponding slot aligned with the slot of the control member guide.

18. A mechanism according to claim 17, wherein the control member has a pin connection to the translation member through the aligned slots, such that the control member can move with respect to the control member guide along the slots.

19. A length adjustable pole, including: an outer tube and an inner tuber slidable within the outer tube; a mechanism according to any one of claims 1 to 18.