GB2615852A

GB2615852A - Latch

Info

Publication number: GB2615852A
Application number: GB2216722.5A
Authority: GB
Inventors: Round Alex; Ellis Stephen; Thomas-Hall Nathaniel
Original assignee: Evac and Chair International Ltd
Current assignee: Evac and Chair International Ltd
Priority date: 2021-11-09
Filing date: 2022-11-09
Publication date: 2023-08-23
Also published as: GB202216722D0

Abstract

A latch comprising a first member such as a rod 610 configured to move linearly and reciprocally along a first path to drive rotation of a second member such as a disc 622a, which then drives the linear movement of a third member such as an engagement pin 624 along a second path which is non-parallel to the first path. The rod and the engagement pin may be constrained to only move along their respective paths. The disc may contain an arcuate slot 623a, wherein the engagement pin is coupled to the disc via a guide pin slidably engaging with the slot. The latch may be used in a bariatric trolley for adjusting a knee-lift mechanism and may comprise a telescopic arm in which the latch is mounted. The latch may be used to position and lock a moveable platform of the trolley in a plurality of configurations.

Description

LATCH

TECHNICAL FIELD

The present invention relates to a latch. Embodiments of the present invention relate to a latch for releasably securing part of a trolley/support apparatus for supporting a person, more particularly a trolley for transporting bariatric patients.

BACKGROUND

A trolley for transporting bariatric patients is generally required to or benefits from having a number of characteristics, including a reinforced base, a wider than conventional mattress, twin side rails for additional width, knee lift and leg raise capabilities, and an upper body torso raise capability.

In the case of a knee-lift mechanism, a number of constraints apply to a latch/release mechanism used to releasably secure the knee-lift mechanism in place. In particular, the knee-lift mechanism is required to be activated from the leg end of the trolley (by a person other than the occupant of the trolley). Moreover, the latch is required to be relatively thin to fit the space available. Still more preferably, due to packaging constraints it is preferable for the latch to have a vertical dimension of less than approximately 20mm, and to fit within a rectangular extruded profile.

Embodiments of the present invention seek to provide a latch for a trolley in which the above requirements are met, and disadvantages are avoided, or at least ameliorated.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided a latch comprising a first movable member, a second movable member and a third movable member, wherein the first member is configured to move linearly and reciprocally along a first path, the second member is configured to rotate, and the third member is configured to move linearly along a second path which is non-parallel to the first path, wherein the linear movement of the first member drives rotation of the second member, and the rotation of the second member drives the linear movement of the third member.

In this way, the latch can be controlled by pulling on the first member, and in particular by pulling it away from the second member. This pulling motion is translated into a different direction by the second member, to retract the third member inwardly towards the second member. The third member may be an engagement pin, shaped and dimensioned to engage with a hole or aperture to secure two parts of a device or assembly (such as an arm) together.

Preferably, the second path is substantially perpendicular to the first path. That is, preferably the pulling motion is translated by 900 by rotation of the second member. This makes it possible for a pulling motion (on the first member) to result in retraction of the third member inwardly of the latch.

The first member is preferably constrained to move only along the first path, and the third member is preferably constrained to move only along the second path. This improves the stability of the mechanism.

The first path and the second path are preferably each directed towards and away from the second member.

The second member may comprise a plate (or disk, these terms being considered equivalent) having an arcuate slot, wherein the third member is coupled to the second member via a (guide) pin which slidably engages with the slot. The use of slotted (rotating) plates and guide pins provides an effective method of transforming a linear input motion into a differently directed linear output motion via an intervening rotational motion.

The latch preferably comprises a body, the second member being rotatably mounted to the body.

The body may comprise a recess in an outside face thereof, the recess being complementary in shape with the second member, the second member being rotatable within the recess. This results in a more slimline mechanism, meeting packaging constraints.

The latch may comprise a sleeve within which the body is disposed, the second member being trapped in the recess by the sleeve, and the sleeve comprising an aperture through which the third member is able to emerge. In some embodiments, the sleeve is part of a telescopic arm (preferably of a trolley), and the need to encapsulate a latch within part of the arm (forming the sleeve) represents a design constraint, and the use of the sleeve to retain components of the latch obviates the need for a separate housing for the latch. However, in other embodiments the sleeve may be a standalone element forming an outer casing which retains the guide pins and the plate/disk.

The body may comprise a channel within which the third member is disposed, the third member being extendable out of the channel and retractable into the channel as it moves along the second path.

The body may comprise a linear slot formed between the inside of the channel and the recess, the pin via which the second and third members are (slidably) coupled together passing through the linear slot in the body. The combination of linear and arcuate slots and pins serves to transform the linear and rotational motions of the latch mechanism.

The latch may comprise a linkage arm which is pivotally mounted at one end to the first member and at its other end to the second member, the linkage arm being disposed within the body. The linkage arm contributes to the transformation of motion, and in particular undergoes a combination of rotational and translational motion to achieve this.

The linkage arm may comprise a first (pivot) pin which engages with the first member and a second (pivot) pin which engages with the second member, the first pin extending through a linear slot within the body to engage the first member and the second pin extending through an arcuate slot in the body to engage the second member, wherein linear movement of the first member causes the first pin to move along the linear slot and the second pin to move along the arcuate slot, wherein the movement of the second pin along the arcuate slot drives rotation of the second member. The first and second pins of the linkage arm define pivots, permitting the respective ends of the linkage arm to pivot with respect to the respective first and second members.

The body may be a two-part body and the linkage arm be disposed in a cavity formed between the two parts of the body, the shape of the cavity permitting movement of the arm as the first and second pins move within their respective slots. This conveniently retains the linkage arm in place, as well as protecting it.

A further third member may be provided, configured to move linearly along a third path which is substantially parallel to the second path, wherein the rotation of the second member drives the linear movement of the further third member along the third path in a direction which is opposite to a direction in which the third member moves along the second path in response to the same movements of the first member and/or second member. The further third member may be an engagement pin, shaped and dimensioned to engage with a hole or aperture to secure two parts of a device or assembly (such as an arm) together. The use of two opposed engagement pins results in a latch with greater stability.

The plate may have a further arcuate slot and the further third member is coupled to the second member via a (guide) pin which slidably engages with the further arcuate slot.

The further third member may be disposed in the same channel as the third member, at an opposite end thereof, the further third member being extendable out of the channel and retractable into the channel as it moves along the third path.

The second member may comprise a further plate, disposed on an opposing face of the body to the plate, the further plate having an arcuate slot, and wherein the pin via which the third member is coupled to the second member extends through the body both in a first direction to engage the arcuate slot of the plate, and a second, opposite, direction to engage the arcuate slot of the further plate.

The plate and the further plate may be connected via a (connection) pin, the pin extending through an arcuate slot in the body, the pin moving along the arcuate slot in the body as the plate and the further plate rotate together. The use of two (upper and lower) plates results in a more robust and stable mechanism, and balances the forces involved in the various motions of the parts.

The first pin of the linkage arm may extend through the body both in a first direction to engage the first member to one side of the body, and in a second, opposite, direction to engage the first member to the opposite side of the body, and/or wherein the second pin of the linkage arm extends through the body both in a first direction to engage the arcuate slot of the plate and in a second, opposite, direction to engage the arcuate slot of the further plate.

The first member may comprise a pair of arms which extend one to each side of the body, the arms each comprising an aperture to receive one end of the first pin of the linkage arm.

The body may comprise a first external channel to one side of the body and in the vicinity of the first pin of the linkage arm, for receiving one of the arms, and a second external channel to the other side of the body and in the vicinity of the first pin of the linkage arm, for receiving the other of the arms, wherein as the first member moves along the first path, the arms slide linearly within the first and second external channels.

The first member may comprise a rod.

Viewed from another, second, aspect, of the invention, there is provided a telescopic arm/extension member comprising first and second parts, the second part being slidably engaged inside the first part, and a latch according to any preceding claim, or according to the first aspect of the invention, wherein the latch is fixedly mounted inside the second part, the third member of the latch being extendable and retractable to engage with and release the first part of the arm, and the first member of the latch extending through the second part of the arm to a handle at one end thereof, the handle and the first member being movable with respect to the second part of the arm to retract the third member from engagement with the first part of the arm.

The telescopic arm preferably comprises a biasing mechanism for biasing the first member towards the second member. In use, the biasing mechanism keeps the two parts of the telescopic arm at a fixed position relative each other until the handle is manipulated by a user. When the user wishes to adjust the length of the arm, they are able to pull on the handle to overcome the bias and draw the first member away from the second member (the body of the latch).

The telescopic arm may include one or more or all the features of the first aspect of the invention.

Viewed from another, third, aspect, of the invention, there is provided a trolley/support apparatus for supporting a person comprising a movable platform and a latch according to the above, the movable platform being lockable in a plurality of different configurations using the latch, wherein the latch is releasable from each lockable position by pulling the first member away from the second member to retract the third member inwardly with respect.

The trolley preferably comprises a telescopic arm according to the above, wherein the movable platform comprises a first panel and a second panel which are hingedly (pivotally) connected together, the first panel being further hingedly (pivotally) connected to the trolley and the second panel being further hingedly (pivotally) connected to the arm, the arm being further hingedly (pivotally) connected to the trolley.

The arm is preferably adjustable to a first length at which the first and second panels are drawn into an angled configuration with respect to each other, to a second length at which the first and second panels form a shared flat surface and are substantially horizontal, and to a third length in which the first and second panels form a shared flat surface which is non-horizontal.

The third aspect of the invention may include one or more or all the features of the first and/or second aspects of the invention.

Viewed from another, fourth, aspect, of the invention, there is provided a support apparatus for supporting a person including a support member including an upper body support member and first and second leg support members, the first and second support members being movable between first, second and third configurations; wherein in the first configuration the first and second support members are at an angle to each other; wherein in the second configuration the first support member and second support member define a shared flat surface and are positioned in substantially the same plane as the upper body support member; and wherein in the third configuration the first and second support members define a shared flat surface which is non-horizontal; wherein the movable platform is lockable in each of the first, second and third configurations using the latch.

The support apparatus for supporting a person may include an extension member to which the latch is fixedly mounted.

The extension member may be movable between a first, fully retracted, position, a second, partially extended, position and a third, fully extended, position.

The first position may correspond to the first configuration.

The second position may correspond to the second configuration.

The third position may correspond to the third configuration.

The fourth aspect of the invention may include one or more or all the features of the first and/or second and/or third aspects of the invention.

Viewed from another, fifth, aspect, of the invention, there is provided a latch according to the first and/or second and/or third and/or fourth aspects of the invention wherein the latch is for use on a support apparatus for supporting a person or preferably an adjustable support apparatus/trolley for a bariatric patient.

Viewed from another, sixth, aspect, of the invention, there is provided a latch according to the first and/or second and/or third and/or fourth aspects of the invention wherein the latch is a support apparatus latch or preferably a bariatric patient adjustable support apparatus/trolley latch.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings where like parts are provided with corresponding reference numerals and in which: Figures 1A and 1B schematically illustrate a trolley for transporting bariatric patients, with Figure 1A showing the trolley as a whole and Figure 1B showing a close up of a knee lift arrangement of the trolley with an extending arm; Figures 2A to 2C schematically illustrate the trolley of Figures 1A and 1B, with the knee lift arrangement in first, second and third configurations; Figures 3A to 3C schematically illustrate an extending arm of the knee lift mechanism at three different states of extension, corresponding to the first second and third configurations of Figures 2A to 2C; Figure 4 schematically illustrates an exploded view of the extending arm of Figures 3A to 3C; Figure 5 schematically illustrates an exploded view of a latch used to secure the extending arm of Figures 3A to 3C and 4 in position; Figures 6A to 6C schematically illustrate the latch of Figure 5; and Figures 7A and 7B schematically illustrate the latch of Figures 5 and 6A and 6B in locking and unlocked states respectively.

DETAILED DESCRIPTION

Referring to Figure 1A, a support apparatus for supporting a person/adjustable support apparatus/trolley 1 for transporting bariatric patients is shown. The trolley 1 includes at least one ground engaging device for permitting movement of the trolley across a surface. In the present embodiment the trolley 1 comprises wheels 2 to permit it to be moved around. The trolley 1 includes a frame 3 for supporting a patient. The frame 3 may be comprised of a plurality of vertical and horizontal structural members. A storage member, or lower platform, 4 may be provided for storage. A support member or an upper platform 5 may be provided for forming a surface for the bariatric patient to reside, or for supporting the bariatric patient when in use.

The upper platform 5 comprises a variety/plurality of different movable surfaces for manoeuvring the patient and their body parts as required. For example, the upper platform may include an upper body support member/panel 5a which can be elevated to raise the patient's upper body and torso. The upper platform may include a pair of (first and second) leg support members/panels 5b, Sc which can be elevated in various combinations to raise the patient's legs and/or knees. The second leg panel Sc in Figures 1A and 1B is shown transparently to provide a view of the mechanism beneath, but in practice is unlikely to be transparent. An extension member, in this example an extending (telescopic) arm, 6 may be provided which is mounted (hingedly or pivotally) to the frame 3 at one end, and (again, hingedly or pivotally) to part of the second leg panel Sc at the other end. The arm 6 can be extended and retracted to elevate and configure the leg panels 5b, Sc. In Figure 1B, the arm 6 is shown transparently, revealing a latch 10 having at least one engagement member or engagement pins (only one engagement pin 625 is shown in Figure 1B, but in practice a further engagement pin is provided to the other side of the latch 10). The engagement member/engagement pins may be used to enable the arm 6 to be retained in a particular state of extension or retraction. It can be seen that the latch 10 is fully concealed within the arm 6 (except in some conditions for the engagement pins which may extend through the arm 6). The latch may be for use on a support apparatus for supporting a person or preferably an adjustable support apparatus/trolley for a bariatric patient. In particular, the latch may be a support apparatus latch or a bariatric patient adjustable support apparatus/trolley latch.

In Figures 2A to 2C, the trolley 1 is shown with a knee-lift arrangement thereof in three different configurations respectively. The knee-lift arrangement can be seen to comprise the first leg panel 5b and second leg panel Sc, which are hingedly (or pivotally) connected together The first leg panel 5b is also hingedly (pivotally) connected to the frame of the trolley 1 (or to another fixed part of the trolley, such as intermediate support member, or static panel, 11 disposed between the upper body panel 5a and the first leg panel 5b). The second leg panel 5c is hingedly (pivotally) connected to one end of the arm 6. Figure 2A shows the trolley 1 in a first configuration in which the first and second leg panels 5b, Sc are at an angle to each other, i.e., the first leg panel 5b is inclined at an angle to the second leg panel Sc, (non-linear) rather than defining a flat surface, with the hinged joint between the first and second leg panels 5b, Sc being elevated, but the hinged joints at the other ends of each of the first and second leg panels 5b, Sc being at the main surface level of the upper platform 5 of the trolley 1. In this configuration an occupant of the trolley may have their knees proximate the hinged joint between the first and second leg panels 5b, Sc, and thus in an elevated position compared with both their torso and feet. The first configuration corresponds to a first, fully retracted, position of the arm 6. In this case the combined length of the arm 6 and the length between the hinged connection of the arm 6 to the trolley 1 and the hinge (pivot) between the first leg panel 5b and the trolley 1 is less than the combined length of the first and second leg panels 5b, Sc. This forces the panels 5b, Sc to hinge (pivot) towards each other.

Figure 2B shows the trolley 1 in a second configuration in which the first and second leg panels 5b, Sc define a shared flat surface, with the hinged joint between the first and second leg panels 5b, Sc (as well as all other parts of the first and second leg panels 5b, Sc) being at the main surface level of the upper platform 5 of the trolley 1. In this configuration an occupant of the trolley may have their legs straight and horizontal. The second configuration corresponds to a second, partially extended, position of the arm 6. In this case the combined length of the arm 6 and the length between the hinged connection of the arm 6 to the trolley 1 and the hinge (pivot) between the first leg panel 5b and the trolley 1 is the same as the combined length of the first and second leg panels 5b, Sc. This results in the arm 6 being parallel with both the first and second leg panels 5b, 6c, and permits the panels 5b, Sc to rest flat on the frame of the trolley 1. In other words the first and second leg panels in the second configuration may be positioned in substantially the same plane.

The first and second leg panels may also be positioned in substantially the same plane as the upper body panel 5a.

Figure 2C shows the trolley 1 in a third configuration in which the first and second leg panels 5b, Sc define a shared flat surface which is non-horizontal, and more particularly which is tilted upwardly with increasing distance from the hinged joint between the first leg panel 5b and the trolley 1. In this configuration an occupant of the trolley may have their legs straight, and elevated. The third configuration corresponds to a third, fully extended, position of the arm 6. In this case the combined length of the arm 6 and the length between the hinged connection of the arm 6 to the trolley 1 and the hinge (pivot) between the first leg panel 5b and the trolley 1 is greater than the combined length of the first and second leg panels 5b, Sc. This draws the panels 5b, Sc apart into the flat surface, and forces the arm 6 to rotate at its hinged connection to the trolley 1 into an elevated position, lifting up the first and second leg panels 5b, Sc as a result.

In the first and second configurations the arm 6 is substantially horizontal, whereas in the third configuration the arm 6 is angled upwards (from its point of connection to the trolley 1) from the horizontal.

The arm 6 is shown in more detail in Figures 3A to 30. The arm 6 is mounted to the frame 3 via a mount 7, which defines a hinge or pivot permitting the arm 6 to rotate between a horizontal position and an inclined position. The arm 6 may include one or more parts which are slidably connectable to each other In embodiments, the arm 6 may be a telescopic arm. The arm 6 may include, or comprise, a first, outer, telescopic part 62, a second, inner, telescopic part 64, an arm mounting member/block 66 (which may be proximate the exposed end of the inner telescopic part 64), for attachment to the knee panel Sc, and a handle 68, which may be mounted to the end of the inner telescopic part 64. The inner telescopic part 64 is slideably engaged with the outer telescopic part 62 to permit the extension and retraction of the arm 6 as a whole. It will be appreciated that the inner telescopic part 64 and the outer telescopic part move linearly relative to each other. The outer telescopic part 62 comprises one or more openings or holes 63a, 63b, 63c (each to both sides of the part 62, although only the holes to one side are visible in Figures 3A to 3C), which are for engagement by the latch 10 (not visible in Figures 3A to 30, but as shown in Figure 18), and in particular by at least one engagement member/pins of the latch 10 which are retractably extendable (from the latch, and from within the inner telescopic part 64) to engage with the holes 63a, 63b, 63c of the outer telescopic part 62. When the engagement pins of the latch 10 are engaged with the holes 63a, the arm 6 is in a fully retracted state (and is locked in that state until the engagement pins are retracted from the holes 63a), when the engagement pins of the latch 10 are engaged with the holes 63b, the arm 6 is in a partially extended state (and is locked in that state until the engagement pins are retracted from the holes 63b), and when the engagement pins of the latch 10 are engaged with the holes 63c, the arm 6 is in a fully extended state (and is locked in that state until the engagement pins are retracted from the holes 63b). When the engagement pins of the latch 10 are not engaged with any holes, the arm can be extended or retracted by pulling or pushing on the handle 68.

The handle 68 is operably, or rigidly, connected, to the engagement pins of the latch 10 (via the mechanism to be described below), such that movement of the handle from a first to a second position (away from the latch 10), causes the engagement pins to move into holes 63a, 63b, 63c when in position. In other words it is necessary to pull the handle 68 to retract the engagement pins and retract or extend the arm. Similarly, the handle 68 may be pushed by hand (towards the latch 10), e.g., from the second to the first position, to extend the engagement pins. In embodiments the handle may be biased towards the first position and/or the engagement pins may be biased towards an extended position. In other words, more preferably a sprung mechanism is used (as will be described below) to bias the latch into a state in which the engagement pins are extended. In the present implementation, the spring loading of the mechanism applies to the handle 68 and a connection member/rod to which the handle 68 is attached, and not the engagement pins themselves. It would therefore be necessary to pull the handle out before any motion of the telescopic arm would be possible. This prevents accidental release of the latch and collapse of the knee-raise mechanism.

In Figure 3A, the arm 6 is shown in the fully extended state, which causes the trolley 1 to adopt the third configuration shown in Figure 20. In Figure 3B, the arm 6 is shown in the partially extended state, which causes the trolley 1 to adopt the second configuration shown in Figure 2B. In Figure 3C, the arm 6 is shown in the fully retracted state, which causes the trolley 1 to adopt the first configuration shown in Figure 2A.

In Figure 4, an exploded view of the inner portion 64 of the arm 6 is shown. The arm may include a main body (which may be a sleeve or inner box) 602, within which the latch 10 is provided, e.g., at one end thereof. A latch mounting member/end cap (slide block) 604 is fixed onto the end of the sleeve 602 at which the latch 10 is provided for mounting the latch relative to the arm. Fixation members/screws 606 extend through both the end cap 604, the sleeve 602 and then into the latch 10, thereby securing the latch 10 in place and the end cap 604 to the end of the sleeve 602. At the other end of the sleeve 602, the arm mounting block 66 is attached to an upper surface of the sleeve 602, e.g., via four screws 608. The arm mounting block 66 comprises two parts, an upper part 66a and a lower part 66b. The screws 608 extend through the sleeve 602 from a lower surface, through the upper surface and into and through the bottom part 66b, and finally into the top part 66a, thereby securing the two parts 66a, 66b of the arm mounting block 66 together, and to the sleeve 602. A frame of the leg panel Sc can be located between the parts 66a, 66b to attach the arm 6 to the leg panel 5c.

A telescopic bung 614 is provided about an end portion of the rod 610, with a smaller diameter portion of the rod 610a extending out of the telescopic bung 614, through an end plate 616, and into the handle 68. The bung prevents the rod 610a from moving more than a predetermined distance out of the sleeve 602. An internal bore of the handle 68 may have internal screw threading, which may engage with external screw threading on the end portion 610a of the rod 610.

The telescopic bung 614 is fixed within the sleeve 602 by the screws 608, which pass through it. The end plate 617 is screwed onto (both parts of) the arm mounting block 66 using screws 609.

The rod 610 extends from the latch 10 through the hollow centre of the sleeve 602. An abutment member, e.g., cotter pin 612 (or other stop), is provided through/at the rod 610 a short distance from the telescopic bung 614. A compression spring 616 is provided about the rod 610, and between the cotter pin 612 and the telescopic bung 614.

In use, when the handle 68 is not being operated the compression spring 616 acts to bias the bung 614 and the rod 610 (via the cotter pin 612) away from each other, thus biasing the rod 610 towards the latch 10. In this (spring biased) state, the engagement pins of the latch 10 are engaged with, or engagable with, (the holes 63a, 63b, 63c in) the outer telescopic part 62 and the arm 6 is not able to be extended or retracted when this engagement occurs. When a user pulls on the handle 68, the force applied overcomes the force of the compression spring 616, and permits the rod 610 to be pulled partially through the telescopic bung 614, and away from the latch 10, which causes the engagement pins of the latch 10 to withdraw out of the holes in the outer telescopic part 62, permitting sliding movement of the inner telescopic part 64 with respect to the outer telescopic part 62. It will be appreciated that the strength of the spring 616 may be such that, when engagement pins of the latch 10 are retracted from the holes in the outer telescopic part 62, that the force exerted by the spring 616 will be greater than the frictional forces acting between the outer telescopic part 62 and the inner telescopic part 64 while the inner telescopic part 64 is being slid out of the outer telescopic part 62. As a result, while the inner and outer telescopic parts are sliding with respect to each other the engagement pins of the latch 10 will be urged outwards (against the inside of the sleeve 602) until they line up with the next set of holes in the outer telescopic part. When this happens the engagement pins of the latch 10 will enter and engage with those holes, locking the inner and outer telescopic parts together at a new position (and thus fixing the length of the arm, and the positioning of the panels 5b, Sc).

At this point, the process can be repeated (the user pulls, or continues to pull on the handle 68), to once again overcome the spring bias to withdraw the engagement pins of the latch from the holes 63a, 63b, 63c in the outer telescopic part 62, to permit the inner telescopic part 64 to be further withdrawn from the outer telescopic part 62 (until the engagement pins of the latch 10 engage yet another pair of holes (of the holes 63a, 63b, 63c) in the outer telescopic part 62).

It will be appreciated that the arm 6 can in this way be extended to and between multiple different lengths, simply by pulling on the handle 68. In order to retract the arm 6, the user will need to hold the inner telescopic part (or the leg panel Sc or its frame) in place with one hand while pulling on the handle 68 with the other hand, to withdraw the engagement pins of the latch 10 from the holes 63a, 63b, 63c of the outer telescopic part 62. While the engagement pins are withdrawn, the user can then push the inner telescopic part 64 back into the outer telescopic part 62. Note that, once the engagement pins are no longer aligned with the holes 63a, 63b, 63c, the user can stop pulling on the handle 68, and optionally push in with the handle 68 if preferred. The inner telescopic part will then slide into the outer telescopic part until the engagement pins of the latch 10 reach the next pair of holes, whereupon they will engage to prevent further retraction. The process can then be repeated to retract the arm 6 further.

The above allows for convenient locking and unlocking of the arm 6 to achieve the desired configurations of the knee raise mechanism.

Referring to Figures, the latch 10 is shown in exploded view.

The latch 10 can be seen to comprise several movable members which translate a linear motion of the pull rod 610 (when pulled by a user via the handle 68) into dual outwards linear motion of the engagement pins of the latch, via rotational motion of an intermediate member. In this regard, the latch 10 can be understood as providing a first movable member (the pull rod 610 and a handle link 620 which couples the pull rod 610 to the remainder of the latch 10), a second movable member (a circular disk or plate 622a), a third movable member (one of the latch engagement pins, labelled 624), and a further third movable member (another of the latch engagement pins, labelled 625).

The first member is configured to move linearly, and reciprocally, along a first path (and is preferably constrained to move only along the first path, by the interaction of the rod 610 with the bung 614 for example), in response to the user pulling on the handle 68 (or in an alternative implementation pushing on the handle 68), or based on the action of the compression spring 616. The second member is configured to rotate, with the rotation being driven by the first member. The third member is configured to move linearly along a second path, which may be non-parallel to the first path, (and is preferably constrained to move only along the second path). The further third member is configured to move linearly along a third path, which may be substantially parallel to (and preferably axially aligned with) the second path (and also non-parallel to the first path). Rotation of the second member drives the linear movement of both the third member (along the second path), and the further third member (along the third path) in a direction which is opposite to a direction in which the third member moves along the second path. This is in response to the same movements of the first member and/or second member. In other words, movement of the first member in one direction along the first path causes the two third members to move towards each other (retracting the latch engagement pins) while movement of the first member in the opposite direction along the first path causes the two third members to move apart (extending the latch engagement pins).

In this implementation the second path and the third path are each substantially perpendicular (orthogonal) to the first path, but in some alternative implementations this may not be the case. It will be understood that the first path and the second and third paths are in the present implementation each directed towards and away from the second member (that is, the main body of the latch 10). The linear movement of the first member drives rotation of the second member, and the rotation of the second member drives the linear movement of the third member(s).

The plate 622a of the second member comprises a first (arcuate) slot 623a. The plate 622a is coupled to the engagement pin 624 of the third member via a guide formation/pin 624a which slidably engages with the slot 622a. The plate 622a also has a further (arcuate) slot 623b and the plate 622a is coupled to the engagement pin 625 of the further third member via a guide formation/pin which slidably engages with the further arcuate slot 623b.

The latch 10 comprises a body, in this case a two-part body comprising a first (upper) part 630a and the second (lower) part 630b. The plate 622a of the second member is rotatably mounted to the body. The body 630a comprises a recess 631 in an outside face thereof, which is complementary in shape with the plate 622a, such that the plate 622a can freely rotate within the recess 631. When assembled, the sleeve 602 within which the latch 10 is disposed traps the plate 622a in the recess. The sleeve 602 comprises an aperture (not shown) through which the engagement pin 624 is able to emerge (to be able to engage with the outer telescopic part).

The body comprises a channel 632 within which the engagement pin 624 and the engagement pin 625 are disposed, at opposite ends thereof. Both the engagement pins 624 and 625 are extendable out of the channel 632 and retractable into the channel 632 as the move along their respective second and third paths. The channel 632 is defined between the two parts 630a, 630b of the body, in particular in the form of two open channels (having a semi-circular cross section) which when the two parts of the body are engaged form a single closed channel having a circular cross section. The body comprises a linear slot 633 formed between the inside of the channel 630 and the recess 631, the guide pin 624a via which the plate 622a and engagement pin 624 are coupled together passing through the linear slot 633 in the body.

A linkage member/arm 634 is provided which is pivotally mounted at one end to the first member (via the handle link 620) and (also pivotally) at its other end to the plate 622a. The linkage arm 634 can be seen to be disposed within the body (that is, it is encapsulated when the latch 10 is fully assembled). In particular, since the body is a two-part body, the linkage arm can be disposed in a cavity 638 formed between the two parts of the body. The linkage arm 634 comprises a first pivot pin 634a which engages with the handle link 620 and a second pivot pin 634a which engages with the plate 622a. The first pivot pin 634a extends through a linear slot 635 within the body to engage the handle link 620 and the second pivot pin 634b extends through an arcuate slot 636 in the body to engage the plate 622a. Linear movement of the rod 610 (and thus the handle link 620) causes the first pivot pin 634a to move along the linear slot 635 and the second pivot pin 634b to move along the arcuate slot 636. The arcuate (part-circular) movement of the second pivot pin 634b along the arcuate slot 646 drives rotation of the plate 622a. It will be appreciated that the shape of the cavity 638 permits movement of the arm 634 as the first and second pivot pins 634a, 634b move within their respective slots. The pivot pins are preferably fixed parts of the linkage arm 634, with respect to which the plate 622a and handle link 620 are able to rotate/pivot. In practice this means that the linkage arm 634 rotates or pivots with respect to the handle link 620 (which is constrained such as to prevent rotation), while the linkage arm 634 and plate 622a effectively both rotate or pivot with respect to each other.

The second member comprises a further plate 622b, disposed on an opposing face of the body to the plate 622a. The further plate 622b has the same structure as the plate 622a, in particular a pair of arcuate slots (which are vertically in line with the arcuate slots of the plate 622a). The guide pins 624a and 625a via which the third member and further third member are coupled to the plate 622a extend through the body both in a first direction (upwards in the Figures) to engage the arcuate slot of the plate 622a, and a second, opposite (downwards in the Figures), direction to engage the arcuate slot of the further plate 622b. In both cases this is via the linear slots 635 defined in the channel 632. The plate 622a and the further plate 622b are connected via a connection member/pin 641, which extends through an arcuate slot 642 in the body, the pin 641 moving along the arcuate slot 642 in the body as the plate 622a and the further plate 622b rotate together. The first pin 634a of the linkage arm 634 extends through the body both in the first direction to engage the handle link 620 to one side of the body, and in a second, opposite, direction to engage the handle link 620 to the opposite side of the body. The second pin 634b of the linkage arm 634 extends through the body both in the first direction to engage the plate 622a and in a second, opposite, direction to engage the further plate 622b.

The handle link 620 of the first member comprises a pair of guide members/arms 620a, 620b which extend one to each side of the body, the arms each comprising an aperture to receive one end of the first pivot pin of the linkage arm 634.

The body comprises a first external channel 650a to one side of the body and in the vicinity of the first pin 634a of the linkage arm 634, for receiving one of the arms 620a, and a second external channel 650b to the other side of the body and in the vicinity of the first pin 634a of the linkage arm 634, for receiving the other of the arms 620. As the first member (rod 610 and handle link 620) moves along the first path, the arms 620a, 620b slide linearly within the first and second external channels 650a, 650b. This ensures that movement of the first member is constrained to the first path (and that rotation of the first member is not possible).

By way of the above-described arm and latch, a trolley comprising a (two-part) movable platform can be adjusted so that the movable platform is lockable in each of two different raised positions and a lowered position using the latch. The latch is releasable from each position by pulling the first member away from the second member to retract the third member(s) inwardly with respect to the latch to release a telescopic arm within which the latch 10 is disposed.

Referring to Figures 6A to 6C, the latch 10 is shown, in an assembled state, in a side view (Figure 6A), plan view (Figure 6B) and cross-sectional view (Figure 60). In Figure 6A, the latch 10 can be seen to have a very narrow profile, of around 16mm, meeting the stringent packaging requirements available. The length of the latch 10, including the pull rod 610, can be seen to be approximately 320mm, although it will be appreciated that longer or shorter mechanisms may be provided for differently sized applications.

In Figure 6B, the latch 10 (with the engagement pins retracted) can be seen to have a width of approximately 37mm, with the main constraint being the diameter of the disks 622a, 622b.

Figure 6C is a cross-section along the line B-B in Figure 6A. The cavity 638 and the linkage arm 634 disposed within it, can be clearly seen here, as well as the arcuate slot 636 within which the second pin 634b travels when driving rotation of the disk 622a (when itself driven by movement of the rod 610 pushing the linkage arm 634).

Referring to Figures 7A and 7B, a plan view of the latch 10 is shown for each of a latched (engagement pins extended) position (Figure 7A) and unlatched (engagement pins retracted) position (Figure 7B). In the latched position, it can be seen that the arms 620a, 620b of the handle link 620 are fully inserted in the exterior channels 650a, 650b. The first movable member is therefore at one extreme end of the first path, and at its closest point to the second member. In this state, the disks 622a are at a first rotational position (with the pin 634b being at one end of an arcuate path at a fixed radial distance from the centre of the disks 622a, 622b, and with the pin 641 being at one end of another arcuate path at a fixed radial distance from the centre of the disks 622a, 622b). The pin 634a and the pin 641 are disposed at or proximate opposite edges of the disk from each other, such that a line drawn between the two pins will intercept the centre of the disks.

As the disks 622a, 622b are rotated, the arcuate slots 623a and 623b rotate with them. The slots 623a, 623b each arc or curve between a first position on the disk and a second position on the disk, wherein the first position is closer to the centre of the disk than the second position. As a result, within a sector of the disk containing one of the arcs, the slot occupies a different radial position at each angle of arc. Since the guide pin 624a is constrained to both follow the slot 623a and the channel 632, rotation of the disk causes the engagement pin 624 (third member) to move inwards or outwardly of the channel. Similarly, since the guide pin 625a is constrained to both follow the slot 623b and the channel 632, rotation of the disk causes the engagement pin 625 (third member) to move inwards or outwardly of the channel (at the same time as the engagement pin 624). This serves to either cause the engagement pins 624, 625 to move inwardly together (retraction) or outwardly together (extension) Together, the two arcuate slots 623a and 623b define a broken S-shape (that is, two arcs facing opposite directions), centred on the centre of the disks.

Claims

CLAIMS1. A latch comprising a first movable member, a second movable member and a third movable member, wherein the first member is configured to move linearly, and preferably reciprocally, along a first path, the second member is configured to rotate, and the third member is configured to move linearly along a second path, which is preferably non-parallel to the first path, wherein the linear movement of the first member drives rotation of the second member, and the rotation of the second member drives the linear movement of the third member.
2. A latch according to claim 1, wherein the second path is substantially perpendicular to the first path.
3. A latch according to claim 1, wherein the first member is constrained to move only along the first path, and the third member is constrained to move only along the second path.
4. A latch according to claim 1 or claim 2, wherein the first path and the second path are each directed towards and away from the second member.
5. A latch according to any preceding claim, wherein the second member comprises a plate having an arcuate slot, and wherein the third member is coupled to the second member via a pin which slidably engages with the slot.
6. A latch according to any preceding claim, comprising a body, the second member being rotatably mounted to the body.
7. A latch according to claim 6, wherein the body comprises a recess in an outside face thereof, the recess being complementary in shape with the second member, the second member being rotatable within the recess.
8. A latch according to claim 7, comprising a sleeve within which the body is disposed, the second member being trapped in the recess by the sleeve, and the sleeve comprising an aperture through which the third member is able to emerge.
9. A latch according to claim 6, 7, or 8 wherein the body comprises a channel within which the third member is disposed, the third member being extendable out of the channel and retractable into the channel as it moves along the second path.
10. A latch according to claim 9 as appendant on claim 5 and claim 7 or claim 8, wherein the body comprises a linear slot formed between the inside of the channel and the recess, the pin via which the second and third members are coupled together passing through the linear slot in the body.
11. A latch according to any preceding claim, comprising a linkage arm which is pivotally mounted at one end to the first member and at its other end to the second member, the linkage arm being disposed within the body.
12. A latch according to claim 9, wherein the linkage arm comprises a first pin which engages with the first member and a second pin which engages with the second member, the first pin extending through a linear slot within the body to engage the first member and the second pin extending through an arcuate slot in the body to engage the second member, wherein linear movement of the first member causes the first pin to move along the linear slot and the second pin to move along the arcuate slot, wherein the movement of the second pin along the arcuate slot drives rotation of the second member.
13. A latch according to claim 11, wherein the body is a two-part body and the linkage arm is disposed in a cavity formed between the two parts of the body, the shape of the cavity permitting movement of the arm as the first and second pins move within their respective slots.
14. A latch according to any preceding claim, comprising a further third member configured to move linearly along a third path which is substantially parallel to the second path, wherein the rotation of the second member drives the linear movement of the further third member along the third path in a direction which is opposite to a direction in which the third member moves along the second path in response to the same movements of the first member and/or second member.
15. A latch according to claim 14 as appendant to claims, wherein the plate has a further arcuate slot and the further third member is coupled to the second member via a pin which slidably engages with the further arcuate slot.
16. A latch according to claim 14 as appendant on claim 9 wherein the further third member is disposed in the same channel as the third member, at an opposite end thereof, the further third member being extendable out of the channel and retractable into the channel as it moves along the third path.
17. A latch according to claim 5, wherein the second member comprises a further plate, disposed on an opposing face of the body to the plate, the further plate having an arcuate slot, and wherein the pin via which the third member is coupled to the second member extends through the body both in a first direction to engage the arcuate slot of the plate, and a second, opposite, direction to engage the arcuate slot of the further plate.
18. A latch according to claim 17, wherein the plate and the further plate are connected via a pin, the pin extending through an arcuate slot in the body, the pin moving along the arcuate slot in the body as the plate and the further plate rotate together.
19. A latch according to claim 17 as appendant on claim 12, wherein the first pin of the linkage arm extends through the body both in a first direction to engage the first member to one side of the body, and in a second, opposite, direction to engage the first member to the opposite side of the body, and/or wherein the second pin of the linkage arm extends through the body both in a first direction to engage the arcuate slot of the plate and in a second, opposite, direction to engage the arcuate slot of the further plate.
20. A latch according to claim 19, wherein the first member comprises a pair of arms which extend one to each side of the body, the arms each comprising an aperture to receive on end of the first pin of the linkage arm.
21. A latch according to claim 20, wherein the body comprises a first external channel to one side of the body and in the vicinity of the first pin of the linkage arm, for receiving one of the arms, and a second external channel to the other side of the body and in the vicinity of the first pin of the linkage arm, for receiving the other of the arms, wherein as the first member moves along the first path, the arms slide linearly within the first and second external channels.
22. A latch according to any preceding claim, wherein the first member comprises a rod.
23. A telescopic arm comprising first and second parts, the second part being slidably engaged inside the first part, and a latch according to any preceding claim, wherein the latch is fixedly mounted inside the second part, the third member of the latch being extendable and retractable to engage with and release the first part of the arm, and the first member of the latch extending through the second part of the arm to a handle at one end thereof, the handle and the first member being movable with respect to the second part of the arm to retract the third member from engagement with the first part of the arm.
24. A telescopic arm according to claim 23, comprising a biasing mechanism for biasing the first member towards the second member.
25. A trolley comprising a movable platform and a latch according to any one of claims 1 to 22, the movable platform being lockable in a plurality of different configurations using the latch, wherein the latch is releasable from each lockable position by pulling the first member away from the second member to retract the third member inwardly with respect to the latch.
26. A trolley according to claim 25, comprising a telescopic arm according to claim 23 or claim 24, wherein the movable platform comprises a first panel and a second panel which are hingedly connected together, the first panel being further hingedly connected to the trolley and the second panel being further hingedly connected to the arm, the arm being further hingedly connected to the trolley.
27. A trolley according to claim 26, wherein the arm is adjustable to a first length at which the first and second panels are drawn into an angled configuration with respect to each other, to a second length at which the first and second panels form a shared flat surface and are substantially horizontal, and to a third length in which the first and second panels form a shared flat surface which is non-horizontal.
28. A support apparatus for supporting a person including a support member including an upper body support member and first and second leg support members, the first and second support members being movable between first, second and third configurations; wherein in the first configuration the first and second support members are at an angle to each other; wherein in the second configuration the first support member and second support member define a shared flat surface and are positioned in substantially the same plane as the upper body support member; and wherein in the third configuration the first and second support members define a shared flat surface which is non-horizontal; wherein the movable platform is lockable in each of the first, second and third configurations using the latch.
29. A trolley according to claim 28 including an extension member to which the latch is fixedly mounted, wherein the extension member is movable between a first, fully retracted, position, a second, partially extended, position and a third, fully extended, position; wherein the first position corresponds to the first configuration; wherein the second position corresponds to the second configuration; and wherein the third position corresponds to the third configuration.
30. A latch according to any one of claims 1 to 22 wherein the latch is for use on a support apparatus for supporting a person or preferably an adjustable support apparatus/trolley for a bariatric patient.
31. A latch according to any one of claims 1 to 22 wherein the latch is a support apparatus latch or preferably a bariatric patient adjustable support apparatus/trolley latch.