Movement control device

Abstract

A movement control device for damping a push latch in both opening and closing directions, comprising a base housing 12, a damper comprising a damper housing 16 and a piston 21 housed in the base hous

Description

Field of the invention The present invention relates to movement control devices, and particularly, although not exclusively, for furniture components such as drawers and doors. Background One type of movement control device is a push latch. Such devices are generally fitted to doors and drawers of furniture items. In use, an operator would push the drawer or door, hence actioning a push rod located within the push latch. The push latch thus opens the door or drawer by a small amount to allow the operator to be able to fit their fingers behind the drawer or door and complete the opening operation. Such push latches are popular because they negate the need for a handle to be included on the outer surface of the drawer / door. Damped push latches are known, such as US 5518223 Al, but it is desirable to minimize the length of a push latch to allow such to be mounted in or on cabinets / units without effecting the structural integrity of the cabinet / unit. WO 2021 / 233657 Al shows another known arrangement. An issue that has been identified to affect the functioning of damped push latches is how they behave if they are not operated in the expected way. For example, in a cabinet with two doors, once one door is open, it would be easy for the user to open the other one simply by pulling it open instead of by pushing and activating its push latch. The push latch thus remains in its "closed" state, and when the door is subsequently being closed it may hit the push latch in such a manner that it activates the latter, which proceeds to cause the door to re-open instead of staying shut. It is desirable that the push latch behaves on closing of the door in a manner that does not depend on whether the door was opened by pushing or pulling. Summary of the invention The present invention provides a push latch of reduced length with a damper housing, indexing mechanism and two springs that are preferably co-axially aligned. The present arrangement provides a movement control device for damping applications such as furniture doors, sliding doors, drawers, lifters, etc. in the opening direction, and ensures that, whether the relevant door, drawer or the like was previously opened by pushing or pulling, when it is being closed the push latch will be able to transition to and stay in a closed state, and not cause the door to rebound. More specifically, the use of two springs in different areas of the push latch, and a piston-pin arrangement in two separable parts, allow the device to work as a push latch as normal if the door was opened by pushing, and as a damper (on the closing stroke) if the door was opened by pulling. In accordance with an aspect of the present invention, there is disclosed a movement control device for damping a push latch in both opening and closing directions, the device comprising: a base housing; a damper comprising a damper housing and a piston operable to be housed in said base housing, wherein the piston is fixed to the base housing or stationary relative to the base housing when in use, and the damper housing is moveable with respect to the base housing between an open position and a closed position; a first spring and a second spring each operable to bias the damper housing towards or in the open position; and means to releasably secure the damper housing in the closed position; wherein the first spring is located in the damper housing, and the second spring is located in the base housing and outside of the damper housing. Preferably, the means to releasably secure the damper housing in the closed position comprises an engagement unit in the damper housing, wherein the engagement unit is separable from the piston and is configured to reversibly engage with the damper housing, wherein the first spring is attached to the engagement unit. Preferably, the means to releasably secure the damper housing in the closed position comprises a pin attached to the engagement unit and a track attached to the damper housing (or the other way round); in other words, said means comprises or is a pin-and-track mechanism. Preferably, when the damper housing is in the closed position the pin is engaged with the track, and when the damper housing is in the open position the pin is either engaged or not engaged with the track. Preferably, the first spring is a compression spring (a spring that can be compressed to a length that is shorter than its natural unstressed length and in that state will tend to expand due to its own restorative force) operable to act between the damper housing and the piston, and wherein the second spring is a compression spring operable to act between the damper housing and the base housing. Preferably, the piston comprises: a piston rod, and a piston head that is disposed in the damper housing and connected to the piston rod, wherein the piston rod extends out of an end of the damper housing and is fixed to the base housing. In accordance with another aspect of the present invention, there is disclosed a movement control device for damping a push latch in both opening and closing directions, the device comprising: a base housing; a damper comprising a damper housing and a piston assembly operable to be housed in said base housing, wherein the damper housing is fixed to the base housing or stationary relative to the base housing when in use, and the piston assembly is moveable with respect to the base housing between an open position and a closed position; a first spring and a second spring each operable to bias the piston assembly towards the open position; and means to releasably secure the piston assembly in the closed position; wherein the first spring is located within the damper housing, and the second spring is located in or is part of the piston assembly and located outside of the damper housing. Preferably, the means to releasably secure the piston assembly in the closed position comprises an engagement unit in the damper housing, wherein the engagement unit is separable from the piston assembly and is configured to reversibly engage with the damper housing, wherein the first spring is attached to the engagement unit. Preferably, the means to releasably secure the piston assembly in the closed position comprises a pin attached to the engagement unit and a track attached to the damper housing (or the other way round); in other words, said means comprises or is a pin-and-track mechanism. Preferably, when the piston assembly is in the closed position the pin is engaged with the track, and when the piston assembly is in the open position the pin is either engaged or not engaged with the track. Preferably, each of the first and second springs is a compression spring operable to act between the damper housing and the piston assembly. Preferably, the piston assembly comprises: a piston housing, a piston rod, and a piston head that is disposed in the damper housing and connected to the piston rod, wherein the piston rod extends out of an end of the damper housing and is fixed to the piston housing. In any of the above devices, preferably: the damper housing comprises damping fluid therein wherein the damper housing is sealed such that the damping fluid is configured to flow past the piston head but not flow outside of the damping housing into a space of the base housing or piston assembly; the base housing comprises a substantially cylindrical body, and wherein the damper housing, first spring, second spring and index mechanism are substantially co-axial within said cylindrical body; at least a portion of the indexing mechanism is located at least partially within the first spring; the damper housing comprises a first plug and said track (or pin) is affixed thereto; the pin is positioned substantially in parallel with the first spring; the damper is a linear damper; and / or the engagement unit comprises means to prevent rotation with respect to the base housing. In accordance with another aspect of the present invention, there is disclosed a movement control device for damping a push latch in both opening and closing directions, the device comprising: a damper comprising a piston assembly and a base housing, wherein the piston assembly is moveable with respect to the base housing between an open position and a closed position; a first spring and a second spring each operable to bias the piston assembly towards the open position; and means to releasably secure the piston assembly in the closed position; wherein the first spring is located within the base housing, and the second spring is located in the piston assembly, and located at least partially outside of the base housing when in the open position. In accordance with an aspect of the present invention, there is disclosed a push latch comprising any of the aforementioned devices. In order that the present invention be more readily understood specific embodiments will now be described with reference to the accompanying drawings. Description of drawings Figure 1 shows a push latch in cross-section with a damper housing in an open position with respect to a base housing. Figure 2 shows the push latch in cross-section with a damper housing in a closed position with respect to a base housing. Figure 3 shows the push latch in cross-section with a damper housing in an open position with respect to a base housing with a different configuration of components compared to Figure 1. Figure 4 shows a close-up of a piston arrangement of the push latch of Figures 1 and 2. Figure 5 shows a close-up of a plug of the damper housing of the push latch of Figures 1 and 2. Figure 6 shows an example of the push latch of Figures 1 to 3 being placed in situ in an aperture of a unit. Figure 7 shows the push latch of Figure 6, with the unit and base housing removed. Figure 8 shows an alternative base housing for the push latch. Figure 9 shows a push latch in cross-section of a second embodiment, with the push latch being in an open position. Figure 10 shows a push latch in cross-section of a third embodiment, with the push latch being in an open position. Figure 11 shows a push latch in cross-section with an alternative indexing mechanism. Figure 12 shows a close-up of a piston of the push latch illustrated in Figure 11. Figure 13 shows a cabinet with a push latch. Description of preferred embodiments The present arrangement looks to provide a push latch of reduced length compared to known arrangements. The present embodiments provide a push latch to be fitted to doors and drawers of furniture items. In use, an operator pushes the drawer or door, hence actioning the push latch. The push latch thus opens the door or drawer by a small amount to allow the operator to be able to fit their fingers behind the drawer or door and complete the opening operation. The damping action on the embodiments of the present invention works on the opening stroke of the push latch as well as during the closing stroke, in other words, when the door or drawer is being opened as well as closed, respectively. The present arrangement looks to provide a push latch that is minimized to an extent that it can be inserted into a (typically) pre-drilled hole inside a cabinet carcass, or the like. So that this is feasible, the hole cannot be too deep, as the structural integrity of the cabinet may be compromised. Typically, the diameter of the aperture would be 10mm. Broadly, the push-latch 10 is shown in Figure 6. There is a base housing 12 dimensioned to fit within a hole within a cabinet C. A dedicated fitment 14 may alternatively be used, as shown in Figure 8. Figure 7 shows a view of the push latch of Figure 6 with the base housing 12 removed. A damper housing 16 is operable to move in a reciprocal manner along the primary axis of the base housing. An adjustable end piece 218 is provided to allow for fine adjustment of the positioning of the push latch 10. The push latch, in accordance with a first embodiment, is shown in greater detail in Figures 1 to 5. Figure 1 shows a push latch in cross-section with a damper housing 16 in a first, open position with respect to a base housing 12. Figure 2 shows the push latch with the damper housing in a second, closed position with respect to the base housing. Figure 3 shows the push latch also in an open position but with the internal components configured differently from Figure 1, as explained below. Figure 1 shows the damper housing 16 that is slidably co-axially mounted within the base housing 12, in a telescopic arrangement. The damper housing 16 is sealed at a first end by plug 18, and at a second end by plug 200. The second end plug 200 may also be termed the bottom plug 200. Damping fluid is contained within the damper housing. An engagement unit or pin assembly 20 is shown in detail in Figure 4, along with a piston head assembly / portion 21. The engagement unit 20 and the piston head portion 21 are both located within the damper housing 16, but are not fixed to each other, as can be seen also in Figure 1, although in Figures 2 and 3 they are shown to abut each other (note that Figure 4 is orientated the other way around). Preferably, an O-ring 22 is provided in the piston head assembly 21. A piston rod 24 is connected to the piston head 21, and to the base housing 12 at point 26. The piston head 21 and O-ring 22 are arranged to resist the flow of damping fluid in one direction, and preferably also resist such flow in the other direction though to a lesser degree. The damper head portion 21 effectively divides the interior of the damper housing 16 into two chambers between which the fluid flows: a first part or chamber closer to the bottom end of the base housing 12 (i.e. an inner chamber in this embodiment), and a second part or chamber further away therefrom (i.e. an outer chamber). The piston head portion 21 and piston rod 24 are operable to be fixed with respect to the base housing 12. The O-ring 22 in the piston head portion 21 is not fixed but movable, for example between two flanges 23A,B of the piston head portion. The piston head portion may comprise means such as protrusions or fin(s) 33, for example in one or more of the flanges, operable to cooperate with groove(s) or recess(es) on the inner diameter of the base housing 12 to help prevent movement or rotation of the piston head 21 and piston 20 relative to the base housing. Preferably the piston rod 24 is operable to be attached to the base housing 12 at the bottom (inner) end of the latter; the attachment may be by way of a friction fit. The engagement unit 20 is not fixed with respect to the base housing or to the damper housing, and can thus be described as a floating unit, in the outer chamber of the damping housing. Plug 18 of damper housing 16 comprises an aperture through which the piston rod 24 passes. Appropriate sealing is provided to ensure that the damping fluid is retained within the damper housing 16 and does not leak into the space inside the base housing 12 outside the damper housing 16. In use, the damper housing 16 is operable to slide co-axially with the base housing 12, thus there is relative movement between the piston 20 and the damper housing 16. Accordingly, during opening and closing strokes of the push latch 10, the damping fluid is operable to be moved from one side of the piston head 20 to the other, and a damping action is provided as is known in linear dampers. One of the opening stroke or closing stroke may be subject to greater hindrance than the other; preferably; this can be determined during the design or manufacturing process depending on the purpose or context of use of the push latch. For example, as shown on the right in Figure 4, this can be implemented by the features included in the two fixed flanges 23A,B of the piston ahead assembly 21; they are axially spaced apart to allow some movement for the O-ring therebetween, and one or both of them may have an outer shape or inner structure (e.g. indentations in the circumference, or a through-hole nearer the center) that allows fluid to flow between the two chambers in a controlled manner. The O-ring 22 is preferably in sealing engagement with the bore of the damper housing 16 (such as by having a substantial same outer diameter as the bore), and may be pressed against one of the two flanges, depending on the direction of the stroke, thus sealing off or enabling alternative flow paths for the damping fluid, and implementing different levels of damping. Similar damping mechanisms are known in the art and are not described in detail here. The engagement unit 20 in the damper housing 16 is operable to slidably move along the length of the latter in the outer chamber 21. It may comprise an elongate body comprising a volume compensator 28, and mounting section 30 configured to engage with the damper housing. The engagement unit 20 comprises means, such as protrusions or fins 32, operable to cooperate with groove(s) or recess(es) on the inner diameter of the base housing 12 to prevent relative rotation of the engagement unit 20 with the damper housing 16 and base housing 12. The engagement unit 20 preferably comprises a flange 31 at the end closest to the piston head 21, and said guiding means 32 may be formed on this flange. Note that, when the damping housing is in the closed position, preferably, it is substantially entirely located in the base housing (as seen in Figure 2); alternatively, it may be partially located in the base housing and partially extending away therefrom just to a smaller extent compared to when in the open position. A first spring 38 is provided within the damper housing 16. A second spring 50 is provided inside the base housing 12 outside the damper housing 16, preferably sharing the same space with at least part of the piston rod. Both springs are configured to urge the damper housing towards the open position when it is in the closed position, the first spring 38 by acting between an interior surface of the damper housing 16 and the engagement unit 20 (preferably a flange 31 at its end) which is disposed inside the damper housing, and the second spring 50 by acting between an outer surface (end plug) of the damper housing 16 and the base housing 12. The second spring 50 may be fixed at one end to a bottom end of the base housing 12, and its other end faces the damper housing 16 but is preferably not attached thereto; alternatively, the second spring is unattached to either base housing or piston head and is thus floating. The first spring 38 is attached to the engagement unit 20 at one end, preferably at the end of the latter closest to the piston head; the other end of the first spring is preferably attached to the damper housing at or near its outside end or the outer plug 200. The push latch 10 comprises an indexing mechanism, as a means to releasably secure the damper housing to the base housing in a closed position. Preferably, the indexing mechanism comprises a latch, and a track 36. The latch is typically a cylindrical rod bent into a C shape, thus creating a C pin 34. In other words, the indexing mechanism is a pin-and-track mechanism. Preferably, the track 36 can be made integrally with the plug 200 of the damper housing 16, but may alternatively be made as a separate item. Prior patent application (EP 4153829 A) by the present applicant describes the works of a similar indexing mechanism, the contents of which are hereby incorporated by reference. The pin 34 is preferably part of the engagement unit 20 and is pivotally mounted on a mounting section 30 of the engagement unit. Restraining means 40 and 42 limit the scope of movement of the pin 34. Restraining means 40 limits the rotation in a notionally horizontal direction, whilst means 42 limited a notionally vertical direction. Such restraints ensure that the pin 34 centers to the track 36 for engagement therewith. Note that in the pin and track mechanism, rather than having the pin as part of the engagement unit and the track as part of the damper housing as described hereinafter and illustrated in Figures 1 to 3, the opposite arrangement is also possible wherein the track is part of the engagement unit and the pin is part of the damper housing, in which case the pin rather than the track is optionally affixed to the plug 200. When the damper housing 16 is urged into the base housing 12, the pin 34 will come into contact with the track 36. The configuration of the camming surfaces of the track 36 are such that the pin will follow path X (see Figure 5). The pin will come to rest at point Y, thus locking the damper housing 16 in position with respect to the piston 20, and hence the base housing 12. This is the closed position of the damper housing, as shown in Figure 2. During opening of a door, if the push latch is used as intended, pushing on the push latch 10 will cause the pin 34 to follow the path Z, and hence release the damper housing 16 from the engagement unit 20. Unhindered, the first compression spring 38 urges the damper housing into the first position (i.e. the position shown in Figure 3). Since the inner end of the first spring 38 is attached to the engagement unit 20, as the spring lengthens, the engagement unit is now urged in the inner direction until it is pressed against the (fixed) piston head 21, and the damper housing 16 is effectively pushed outward, and eventually reaches the open position shown in Figure 3, where it will stay without further intervention. Note that in this process, substantially all of the damping fluid needs to flow into the outer chamber inside the damping housing through the piston head portion 21 (as the inner chamber has been gradually reduced in volume, to substantially nothing), thus providing a damping effect on the opening stroke due to the arrangement of the piston head portion and O-ring. Starting from the configuration of Figure 3, during closing of the door, the damper housing 16 is pushed in the inward direction. At the end of this process, the track and pin come into contact and are engaged together with the result that the damping housing 16 is retained in the closed position (Figure 2) as described above. During this closing process, the first spring 38 and the second spring 50, both compression springs, are compressed, providing a certain degree of resistance to the contraction of the push latch. In addition, at least part of the damping fluid will be forced to flow through the piston head portion 21 from the outer chamber to the inner chamber of the damping housing 16 as the volume of the outer chamber reduces; this may also provide a damping effect, that is substantially less than that in the other direction described above. Note that in the whole normal closing process, from Figure 3 to Figure 2, the engagement unit 20 is in contact with the piston head 21 due to the action of the first spring 38. According to the first embodiment, in the case that a person does not push the cabinet door and push latch whilst in the closed position (Figure 2) and thus fails to activate the latch to lengthen under the action of the first spring 38 into the open position (Figure 3), but instead simply pulls open the door, the engagement unit 20 will remain secured with the damping housing 16 as there has been no way for the pin to be freed from the track. However, due to the presence of the second compression spring 50, the push latch does not remain stationary; the second spring 50 lengthens to restore its natural length, pushing the damper housing 16 towards the open position (Figure 1). This is again subject to a damping effect due to flow of damping oil across the piston head 21. As the engagement unit 20 is not formed with the piston head 21, and is still attached to the damper housing 16 via the indexing mechanism, it will move with the damper housing 16 in the opening direction. The first spring 38 is attached to the engagement unit 20 and thus remains compressed, and is effectively disabled and does not contribute to urging the damper housing 16 into the open position. The engagement unit 20 is no longer in contact with the piston head 21, as can be seen in Figure 1. Note that this is a second way for the push latch to transition from the closed position (Figure 2) to an open configuration, as illustrated in cross section in Figure 1, which differs in the arrangement of the internal components, from that open configuration illustrated in Figure 3, which results from opening the door by activating the push latch. Now, starting from the open position of Figure 1 in which the engagement unit 20 is retained with the damper housing 16, as closing progresses the damping action due to (i) the damping fluid flow from outer to inner chamber through the piston head 21 and (ii) compressing the second spring 50 will cause the door to close more slowly, with the advantage that it is less likely to culminate in activation of the index mechanism. Therefore, the latch / damping housing 16 stay in the closed configuration (Figure 2), and the door does not risk bouncing back. Note that it is not possible that the latch goes directly from the configuration of Figure 1 to that of Figure 3 or vice versa, except through Figure 2. There are several things to note regarding the restoring forces of the two compression springs to ensure proper functioning of the push latch as described above, with reference to Figure 13, which shows a cabinet C with a door having two hinges H and installed a push latch device P (of any embodiment herein described). Preferably, the first spring 38 is stronger than the second spring 50. As the first spring is responsible for urging the damper housing 16 towards the open position (from Figure 2 to Figure 3), causing the hinged door of a cabinet, for example, to open, the restoring force of the first spring 38 should be greater than any resistive force due to the hinge(s) 910 of the door that needs to be overcome (and the resistive force due to the damping mechanism). The restoring force of the second spring 50 that urges the damper housing 16 towards the open position (from Figure 2 to Figure 1) should be sufficient to overcome the resistive force due to the damping mechanism, but should be weaker than any force exerted by the hinge(s) of the door, that is to say the second spring should not excessively resist the closing of the door (from Figure 1 to Figure 2). Thus, it is preferable that the restorative force of the first spring is greater than a hinge force applicable to the door for which the push latch device is responsible, and that of the second spring is less than said hinge force. It will be appreciated that, during a working stroke of the push latch the damping fluid is urged from one side of the piston head 21 to the other. In Figure 2, at least some of the damping fluid is on the left side of the piston as viewed. In Figure 3, the damping fluid is substantially entirely on the right side of the piston. As mentioned, the passage of fluid from the left to the right of the piston head is subject to greater damping, that is from the closed position (Figure 2) to the open position (Figure 3), compared to its passage from the right to the left, that is from the open position (Figure 3) to the closed position (Figure 2). Alternatively, the relative extents of the damping effect may be the other way round, depending on the use case. Thus, if an oil is used, the spring 38, pin 34, track 36 are all lubricated, thus prolonging use. By locating the indexing mechanism at least partially within the internal diameter of the first spring 38, the length of the push latch 10 can be reduced. Accordingly, it becomes feasible to manufacture a push latch that is operable to fit within a pre-drilled hole within a furniture carcass. The pin 34 is partially maintained within the first spring at all times. Particularly, in the second position the pin is at least partially within the first spring. The pin is maintained wholly within the spring when the damper housing is in the first position if the engagement unit 20 is disengaged from the damper housing. The piston rod 24 is preferably at least in part surrounded by the second spring 50. The first spring 38, second spring 50, the track of the indexing mechanism 36 and the damper housing 16 are all preferably co-axially aligned. The pin 34 of the indexing mechanism is mounted parallel to the central axis of the springs 38, 50 and the piston rod 24. The pin 34 is mounted off-center to allow engagement with the track 36. However, the indexing mechanism is essentially co-axial with the damper housing and the springs. Accordingly, the push latch can be made smaller in length, and have a reduced width. The co-axial alignment of the above features also makes it possible to manufacture the push latch 10 to have a substantially cylindrical shape. As such, the push latch can be readily inserted into holes drilled within furniture carcasses. By placing the track 36 of the indexing mechanism inside the damper housing, the track is kept free from debris, and hence maintains working life of the push latch. Figure 9 shows a push latch device 10' in cross-section in accordance with a second embodiment in an open position (similar to Figure 3 of the first embodiment). In this embodiment it is a piston assembly 25 that moves with respect to the base housing 12' in a telescopic arrangement, with the damper housing 16' remaining stationary in use. The damping fluid / liquid / oil is contained in the damper housing. The piston assembly 25 may comprise a piston housing 27, a piston rod 24', and a piston head portion 21' that is disposed within the damper housing 16' and connected to the piston rod, wherein the piston rod extends out of an end of the damper housing and is fixed to the piston housing. The piston housing 27 is operable to slide between the base housing 12' and the damper housing 16'. As in the first embodiment, the piston head 21' in the damper housing compartmentalises the space in the latter into two chambers or parts, between which damping fluid flows, causing a damping effect on the opening and closing strokes; the piston head preferably comprises two flanges between which an O-ring is provided. An index mechanism is provided as a means to releasably secure the piston assembly 25 to the base housing 12' in a closed position. Similar to the first embodiment, the index mechanism comprises an engagement unit 20' disposed in the damper housing 16' that is slidably moveable therewithin, and it is preferably a pin-and-track mechanism. Two compression springs are provided in the device. The first spring 38 is disposed in the damper housing and connected to the engagement unit, and is configured to urge the piston assembly towards the open position; it acts between a bottom end (plug) of the damper housing (and thus the base housing) and the engagement unit 20 (preferably a flange 31 at its end). The second spring 50 is in the piston assembly (preferably fully inside the piston housing) and also configured to urge the piston assembly towards the open position; it acts between an outer surface (end plug) of the damper housing and an internal surface at the outer end of the piston assembly / housing, as can be seen in Figure 9. Note that, when the piston assembly / housing 27 is in the closed position, preferably, it is substantially entirely located in the base housing 12'; alternatively, it may be partially located in the base housing and partially extending away therefrom just to a smaller extent compared to when in the open position. Optionally, the damper housing is provided with an adjustable end piece that allows for position / length adjustments (before installation of the latch device). Similar to the first embodiment, in the pin-and-track mechanism, the pin is preferably part of the engagement unit, and the track is preferably part of / attached to the damping housing (plug); however, it is also envisaged that their positions can be swapped whereby the track is in the engagement unit and the pin is part of the damping housing (plug) in which case the pin rather than the track can be optionally attached to the damping housing. Figure 10 shows a push latch device 10” in cross-section in accordance with a third embodiment in an open position (similar to Figure 3 of the first embodiment and Figure 9 of the second embodiment). The third embodiment is similar to the second embodiment, in that there is a piston assembly 25' that moves with respect to a stationary base housing 12” in a telescopic arrangement. However, the damper housing and the base housing are formed as one piece or can be considered as one single piece; in other words, the push latch device may be described as having no separate damper housing, and the damping fluid / liquid / oil is contained in the base housing. Having noted this, for the sake of convenience, when describing the third embodiment below we continue to refer to a damper housing with the understanding that it is equivalent to the base housing, as the term "damper housing" can be taken to simply mean a container of damper fluid. In this embodiment, the piston assembly 25' may not include a full piston housing to contain the piston rod, but a piston end cap 29 which is the point of contact with the furniture door or drawer. The piston assembly may comprise the piston rod 24”, and a piston head portion 21” that is disposed within the damper housing 12” and connected to the piston rod, wherein the piston rod extends out of an end of the damper housing and is fixed to the piston end cap 29. As in the first embodiment, the piston head 21” in the damper housing compartmentalises the space in the latter into two chambers or parts, between which damping fluid flows, causing a damping effect on the opening and closing strokes; the piston head preferably comprises two flanges between which an O-ring is provided. An index mechanism is provided as a means to releasably secure the piston assembly 25' to the base housing 12” in a closed position. Similar to the first embodiment, the index mechanism comprises an engagement unit 20” disposed in the damper housing 12” that is slidably moveable therewithin, and it is preferably a pin-and-track mechanism. Two compression springs are provided in the device. The first spring 38 is disposed in the damper housing and connected to the engagement unit, and is configured to urge the piston assembly towards the open position; it acts between a bottom end (plug) of the damper housing (and thus the base housing) and the piston head portion of the piston assembly which is disposed inside the damper housing. The second spring 50 is in the piston assembly or can be considered part of the piston assembly (disposed between the piston end cap and the piston head) and is also configured to urge the piston assembly towards the open position; it acts between an outer surface (end plug) of the damper housing and the piston end cap at the outer end of the damper assembly, as can be seen in Figure 10. As in the second embodiment, the second spring substantially or at least partially extends out of the base housing when the device is in the open position. Note that, when the piston assembly is in the closed position, preferably, it is substantially entirely located in the base housing; alternatively, it may be partially located in the base housing and partially extending away therefrom just to a smaller extent compared to when in the open position. For avoidance of doubt, in all of the first, second and third embodiments, the second spring 50 does not come into contact with the damping fluid and is outside of the container (damper housing 16,16' or base housing 12”) of the damping fluid, whereas the first spring 38 comes into contact with the damping fluid as it is inside the container (damper housing 16, 16' or base housing 12”) of the damping fluid. In the third embodiment, as there is no piston housing apart from an end cap 29 in the piston assembly 25' of the push latch device, it is not necessary to have a gap or space in the base housing 12” for a tube (of a piston housing) to slide into (cf. the gap between the damper housing 12' and base housing 16' in the second embodiment). Manufacture can be simplified. However, the piston rod and the second spring are exposed. In the third embodiment, optionally, means may be provided to adjust the position or extension length of the piston rod 24” and thus that of the piston assembly 25'. For example, the engagement between piston rod and the piston head 21” may comprise a screw thread (not illustrated); by rotating the rod, the length of the rod extending from the base housing 12” when in the open position can be increased or decreased. This may also be applicable in the second embodiment as a way to adjust the position or extension of the piston assembly 25 out of the base hose housing 12'. Furthermore, in the third embodiment there is no adjustment means such as an adjustable end piece to allow for position / length adjustments between the damper housing and base housing since they are not separate, and as a result, for example, the track of the pin-and-track mechanism is configured to be affixed to an end inside the base housing. Without such an adjustment end piece, the overall length of the device can be reduced. In the pin-and-track mechanism, the pin is preferably part of the engagement unit, and the track is preferably part of / attached to the base housing, as mentioned; however, it is also envisaged that their positions can be swapped whereby the track is in the engagement unit and the pin is part of the base housing. Despite the modifications, generally, in the second and third embodiments the operation of the mechanisms for the relative movements between the damper housing / base housing and the piston assembly, and the damping effects thereof, are the same as in the first embodiment. For example, the parallel relationships between various components in the push latch are preferably the same or similar. Preferably, the two springs are substantially coaxial. Preferably, the damper housing and indexing mechanism are all substantially mounted co-axially; particularly, the springs, damper housing and track of the indexing mechanism are mounted co-axially. The pin of the indexing mechanism is mounted in parallel with the spring and the piston rod, positioned off-center thereto. Other features described in relation to the first embodiment, such as the means to limit the movement of the pin, and the means to ensure that there is minimal rotation of the respective components are equally applicable to the other embodiments. Alternative indexing mechanisms may be used. For example, a rotational mechanism similar to that disclosed in EP 2147179 may be used. This is shown in Figures 11 and 12, wherein the rotational pin 34' is guided in the track 36', 36''. It can be seen in Figure 12 that, in accordance with the "two-part" design as described above, the components that move with the engagement unit are not integrally formed with and are separable from the components that stay as part of the piston head assembly during the working strokes of the device. The damper could be a fluid damper with a piston and O-ring arrangement, as described above. Alternatively, a frictional piston and O-ring arrangement may be used. In case of a frictional piston and O-ring design, a frusto-conical shaped expander 220 is operable to urge against the O-ring produce a higher friction in the opening direction. A ring expandable in the circumferential direction could also be used. A flat-faced piston ring 222 may urge the O-ring 22 back in the closing direction, hence providing a lower friction in the closing direction. A push latch piston could also be designed as an air damper as disclosed in EP 1717396 A. The 5 contents of which are hereby incorporated by reference. It is to be understood that the embodiments described herein are for reference purposes only, and that the scope of the invention is to be determined by the appended claims. Many modifications and variations are possible within the scope and spirit of the invention.

Claims

1. A movement control device for damping a push latch in both opening and closing directions, the device comprising:a base housing;a damper comprising a damper housing and a piston operable to be housed in said base housing, wherein the piston is fixed relative to the base housing, and the damper housing is moveable with respect to the base housing between an open position and a closed position;a first spring and a second spring each operable to bias the damper housing towards the open position; andmeans to releasably secure the damper housing in the closed position;wherein the first spring is located within the damper housing, and the second spring is located within the base housing and outside of the damper housing.

2. The movement control device according to claim 1, wherein the means to releasably secure the damper housing in the closed position comprises an engagement unit in the damper housing, wherein the engagement unit is separable from the piston and is configured to engage with the damper housing, wherein the first spring is attached to the engagement unit.

3. The movement control device according to claim 2, wherein the means to releasably secure the damper housing in the closed position comprises a pin attached to the engagement unit and a track attached to the damper housing or vice versa.

4. The movement control device according to claim 3, wherein:when the damper housing is in the closed position the pin is engaged with the track, and when the damper housing is in the open position the pin is either engaged or not engaged with the track.

5. The movement control device according to claim 2, wherein the first spring is a compression spring operable to act between the damper housing and the engagement unit, and wherein the second spring is a compression spring operable to act between the damper housing and the base housing.

6. The movement control device according to any one of claims 1 to 5, wherein the piston comprises: a piston rod, and a piston head that is disposed within the damper housing and connected to the piston rod, wherein the piston rod extends out of an end of the damper housing and is fixed to the base housing.

7. A movement control device for damping a push latch in both opening and closing directions, the device comprising:a base housing;a damper comprising a piston assembly and a damper housing operable to be housed in said base housing, wherein the damper housing is stationary with respect to the base housing when in use, and the piston assembly is moveable with respect to the base housing between an open position and a closed position;a first spring and a second spring each operable to bias the piston assembly towards the open position; andmeans to releasably secure the piston assembly in the closed position;wherein the first spring is located within the damper housing, and the second spring is located in the piston assembly and outside of the damper housing.

8. The movement control device according to claim 7, wherein the means to releasably secure the piston assembly in the closed position comprises an engagement unit in the damper housing, wherein the engagement unit is separable from the piston assembly and is configured to engage with the damper housing, wherein the first spring is attached to the engagement unit.

9. The movement control device according to claim 8, wherein the means to releasably secure the piston assembly in the closed position comprises a pin attached to the engagement unit and a track attached to the damper housing or vice versa.

10. The movement control device according to claim 9, wherein:when the piston assembly is in the closed position the pin is engaged with the track, and when the piston assembly is in the open position the pin is either engaged or not engaged with the track.

11. The movement control device according to claim 8, wherein the first spring is a compression spring operable to act between the damper housing and the engagement unit, andwherein the second spring is a compression spring operable to act between the damper housing and the piston assembly.

12. The movement control device according to any one of claims 7 to 11, wherein the piston assembly comprises: a piston housing, a piston rod, and a piston head that is disposed within the damper housing and connected to the piston rod, wherein the piston rod extends out of an end of the damper housing and is fixed to the piston housing.

13. The movement control device according to any preceding claim, wherein the damper housing comprises damping fluid therein, wherein the damper housing is sealed such that the damping fluid is configured to flow past the piston head but not flow outside of the damping housing.

14. The movement control device according to any preceding claim, wherein the base housing comprises a substantially cylindrical body, and wherein the damper housing, first spring, second spring and index mechanism are substantially co-axial within said cylindrical body.

15. The movement control device according to any preceding claim, wherein at least a portion of the indexing mechanism is located at least partially within the first spring.

16. The movement control device according to any preceding claim, wherein the damper housing comprises a first plug, and said track or pin is affixed thereto.

17. The movement control device according to any preceding claim, wherein the pin is positioned substantially in parallel with the first spring.

18. The movement control device according to any preceding claim, wherein the damper is a linear damper.

19. The movement control device according to any preceding claim, wherein the engagement unit comprises means to prevent rotation with respect to the base housing.

20. A movement control device for damping a push latch in both opening and closing directions, the device comprising:a damper comprising a piston assembly and a base housing, wherein the piston assembly is moveable with respect to the base housing between an open position and a closed position;a first spring and a second spring each operable to bias the piston assembly towards the open position; and5 means to releasably secure the piston assembly in the closed position;wherein the first spring is located within the base housing, andwherein the second spring is located in the piston assembly, and at least partially outside of the base housing when the piston assembly is in the open position.21

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