Patent Publication Number: US-9414724-B2

Title: Damped hinge assemblies

Description:
This invention relates to damped hinge assemblies and more particularly, though not exclusively, to damped hinge assemblies for mounting elements such as lids, seats and doors. 
     The invention provides a damped hinge assembly for mounting a first member for pivotal movement relative to a second member about an axis of rotation. The assembly comprises a linear damper, means mounting the damper with its longitudinal axis parallel to the hinge axis, and camrning means for converting pivotal movement of the first member in at least one direction of rotation into linear displacement of the damper to cause the damper to produce a damped resistive force to counter said pivotal movement of the first member. The longitudinal axis of the damper is arranged to be coincident with the hinge axis. 
    
    
     
       By way of example, embodiments of the invention will now be described with reference to the accompanying drawings, in which: 
         FIG. 1  shows a first form of a damped hinge assembly according to the invention (shown partly cut-away to reveal detail), 
         FIG. 2  is a detail view of the drive mechanism of the assembly of  FIG. 1 , 
         FIG. 3  is an exploded view of the  FIG. 2  detail, 
         FIG. 4  shows a second form of a damped hinge assembly according to the invention (shown partly cut-away to reveal detail), 
         FIGS. 5 and 6  show in partly cut-away detail the damping unit of the assembly of  FIG. 4 , and 
         FIG. 7  shows in partly cut-away detail an alternative form of a damping unit for the assembly of  FIG. 4 . 
     
    
    
     The damped hinge assembly seen in  FIG. 1  is for use on a lavatory seat  11 . The lavatory seat  11  comprises a lid member  12  and a seat member  13 , both of which are pivotally mounted onto the lavatory  14  by a hinge mounted on a block  22  (shown partly cut away in the drawings). The block  22  is anchored to the lavatory  14  by the usual spaced apart threaded fasteners  16 . The arrangement enables both the lid and seat members  12 ,  13  to be pivotable between a lower, generally horizontal position resting on the lavatory  14  and a raised position, generally slightly beyond vertical and resting against a cistern or wall or the like. 
     The assembly is arranged to provide a damped resistive force to counter the pivotal movement of both the lid and seat members  12 ,  13  as they move under gravity from their raised position to their lowered position. This is intended to avoid possible damage that could otherwise occur if the lid and/or seat members were accidentally allowed to fall freely onto the lavatory. 
     The assembly comprises a damper  17 , which is conveniently located in the space between the hinge block mounting threaded fasteners  16 . The damper  17  here is a linear damper of the piston and cylinder variety, with a piston (not shown) connected to a piston rod  18  and acting within a cylinder  19  on a damping medium (not shown) such as silicone (see  FIG. 3 ). The damper  17  incorporates a spring (not shown) arranged to bias the piston rod  18  towards its extended position. The damper  17  is designed here to provide the damped resistive force to the lid and/or seat members  12 ,  13  in response to its axial compression. However, the damper  17  provides no damped resistance upon its axial extension. 
     As will be seen in the drawings, the damper  17  is mounted on the block  22  and arranged with its longitudinal axis coincident with the pivotal axis  20  of the assembly. The damper  17  is captured in this position between two spaced apart end caps  21   a ,  21   b . Each end cap  21   a ,  21   b  is generally cylindrical and has an axially extending rib  23   a ,  23   b  which engages in a groove  24  in the block  22 . The groove  24  extends parallel to the pivotal axis  20  of the assembly. The arrangement means that the two end caps  21   a ,  21   b  are both capable of linear movement parallel to the pivotal axis  20  of the assembly (both towards and away from each other), but are prevented from rotating relative to the block  22 . Thus, movement of the end caps  21   a ,  21   b  towards each other will cause axial compression of the damper  17 , whilst movement of the end caps  21   a ,  21   b  away from each other will allow axial extension of the damper, under the influence of its spring. 
     As will be seen in the drawings, the lid and seat members  12 ,  13  each have a respective driving element  30   a ,  30   b  associated therewith. Each driving element  30   a ,  30   b  is rotatably mounted on the assembly by a spindle  31   a ,  31   b  journalled in a bore in the block  22 . The axis of rotation of the spindles  31   a ,  31   b  is coincident with the pivotal axis  20  of the assembly. Each driving element  30   a ,  30   b  is arranged to be keyed to its respective lid/seat member  12 ,  13  to rotate therewith. In the case of the lid member  12 , for example, it can be seen in the drawings how the spindle  31   a  of its respective driving element  30   a  is provided with flats  37   a  and fits in a flatted hole  36  in the hinge part of the lid member. The arrangement means that whenever the lid member  12  is pivoted, the spindle  31   a  and hence its associateda driving element  30   a  will likewise be driven to rotate. In a similar manner, the spindle  31   b  is provided with flats  37   b  and fits in a flatted hole in the hinge part of the seat member  13 , so that whenever the seat member is pivoted, the spindle  31   b  and hence its associated driving element  30   b  will likewise be driven to rotate. 
     Each driving element  30   a ,  30   b  has circumferentially extending ramped surfaces  34   a ,  34   b  on its axially inwardly facing end. For balance, the ramped surfaces are provided on their elements as diametrically opposed pairs, as can be seen in the case of the driving element  30   b  for the seat member in  FIG. 3 . Each of these ramped surfaces  34   a ,  34   b  is engaged by a respective nib  35   a ,  35   b  on the end caps  21   a ,  21   b  (again provided as diametrically opposed pairs). The nibs  35   a ,  35   b  will be biassed into engagement with their respective ramped surfaces  34   a ,  34   b  by the action of the spring in the damper  17 . It will be understood that this arrangement means that when either of the driving elements  30   a ,  30   b  rotates, its ramped surface  34   a ,  34   b  will act on the respective nib  35   a ,  35   b  to cause longitudinal displacement of its respective end cap  21   a ,  21   b . The ramped surfaces  34   a ,  34   b  and nibs  35   a ,  35   b  thus act in the manner of a cam and cam follower, translating rotational movement into linear movement. The rotational movement of the lid and/or seat members  12 ,  13  is thus translated by this motion converting mechanism into linear displacement (extension or compression) of the damper  17 . 
     In  FIG. 2 , for example, the assembly is seen in its condition when the lid member is in its raised position, whilst the seat member is in its lower position. The driving element  30   b  associated with the seat member has been rotated in the direction of arrow A as the seat member has been lowered. This has driven its associated end cap  21   b  in the direction of arrow B by the caroming action of the ramped surface  34   b  on the nib  35   b . Movement of the end cap  21   b  in this manner has caused compression of the damper  17 , thereby imparting a damped resistive force to the lowering movement of the seat member. 
     It will be understood that the manner of engagement of the nibs  35   a ,  35   b  on their respective ramped surfaces  34   a ,  34   b  needs to be capable of sliding contact. This can be achieved by conveniently making the components of the assembly of moulded plastics material. It will also be understood that the nibs  35   a ,  35   b  engage their respective ramped surfaces  34   a ,  34   b  over a discrete and relatively small contact area. This allows the possibility for the profile of the ramped surfaces  34   a ,  34   b  to be configured in an almost infinite variety of different ways in order to suit different requirements. 
     Here, the ramped surfaces  34   a ,  34   b  on the driving elements  30   a ,  30   b  are configured such that pivotal movement of the lid and/or seat members  12 ,  13  in their lowering direction will cause linear movement of the end caps  21   a ,  21   b  in a direction towards each other. The effect of this will be to cause axial compression of the damper  17 . Axial compression of the damper  17  will in turn create a resistive damping force which is transmitted back through the drive mechanism to the lid and/or seat members  12 ,  13  and hence attenuate their closing movement. 
     It will be noted that the damper  17  will be actuated to provide a damped resistive force to the closing movement of the lid or seat members  12 ,  13  moving singly, as well as to the closing movement of the two members moving together. 
     The effect of the force of gravity acting on the lid and seat members  12 ,  13  will not be constant throughout their pivotal movement. In fact, the force will increase progressively as the lid/seat members  12 ,  13  pivot from their initial generally upright position towards their lower, generally horizontal position. Ideally, the assembly will be tailored to accommodate this variable force. This can be achieved in the assembly here by suitably configuring the profile of the ramped surfaces  34   a ,  34   b  on the driving elements  30   a ,  30   b . The amount of resistive damping force that the damper  17  generates is basically proportional to the rate of its axial compression: a higher rate of compression produces a larger damped resistive force and vice versa. If the ramped surfaces  34   a ,  34   b  on the driving elements  30   a ,  30   b  follow a plain helical pattern, this will produce a constant amount of linear displacement of the end caps  21   a ,  21   b  per degree of rotation of the driving elements, i.e. a constant rate of axial compression of the damper  17 . If the ramped surfaces  34   a ,  34   b  are instead configured to have an increasingly steep profile beyond helical, then this will cause an increasingly rapid rate of axial compression of the damper  17  per degree of rotation of the driving elements  30   a ,  30   b . The damped resistive force from the assembly can thus be matched to the variable load from the lid/seat members. 
     The profiling of the ramped surfaces  34   a ,  34   b  can also be configured to determine the precise range of rotational movement of the lid and seat members  12 ,  13  during which the damper is to provide damped resistance. For example, it might typically be preferred for there to be no damping force during the first  20   o  of the initial rotational movement of the lid and seat members from their upright position towards their lower position. In that case, each ramped surface  34   a ,  34   b  would be configured with an initial section of its profile lying normal to the pivotal axis  20 . 
     The assembly will normally be designed not to impart any damping force to oppose the opening movement of the seat and lid members upwardly from their lower position. For this purpose, the damper may incorporate a valve mechanism in its piston. 
     It is not essential for the damper to incorporate a spring: an alternative mechanism could be provided for urging the damper towards its extended position. In one example, the free end of the piston rod could be attached to the surface against which it is arranged to act. 
     In the assembly described above, although the damper is conveniently located within it, there is nevertheless enough room to fit in a unit with a sizeable damping capacity. If necessary, however, the damper could be augmented by one or more additional dampers mounted in parallel. 
     In a modified arrangement, the assembly could be designed to accommodate two separate dampers aligned along the pivotal axis. In that case, the dampers could be arranged to react against a common fixed point in the assembly, for example in the form of a central wall within the block. Each of the dampers would then separately serve a respective one of the seat and lid members. An advantage of this arrangement would be that the members will be able to experience the same level of damping force regardless of whether they are lowered separately or together. In the arrangement with just a single damper, the effect of the damping force will be less if the seat and lid members are lowered together than if they are lowered individually. 
       FIG. 4  shows a second form of damped hinge assembly, again for use on a lavatory seat  11  comprising a lid member  12  and a seat member  13 , both of which are pivotally mounted onto a lavatory  14 . In this case, the pivotal mounting of the lid and seat members  12 ,  13  comprises a pair of separate mounting units  50   a ,  50   b . The mounting units  50   a ,  50   b  are anchored to the lavatory  14  by threaded fasteners  16  located in the usual spaced apart mounting holes. 
     The mounting units  50   a ,  50   b  are essentially identical, and each comprises a block  51   a ,  51   b  (shown partly cut away) which is effectively fixed to the lavatory  14 . In each block  51   a ,  51   b , there is mounted a hinge damper unit  52 . As will be explained in more detail, the pair of hinge damper units  52  together provide a dual function: firstly, they provide a pivotal mounting for the lid and seat elements  12 ,  13 , and, secondly, they provide a resistive damping force to their closing movement. 
     The construction of each hinge damper unit  52  is seen in more detail in  FIGS. 5 and 6  and consists of a housing  53 , a damper  54  and a drive cap  55 . At one end the housing  53  has an externally splined section  56  by which it can be mounted to the block  51   a ,  51   b : this holds the housing non-rotatably fixed to the block. At its other end the housing  53  has a plain cylindrical surface  57 : this acts as a spindle for the pivotal mounting of one of the lid and seat elements  12 ,  13 . 
     The housing  53  is closed off at one end by an end wall  58 . At the other end of the housing  53 , the drive cap  55  is mounted. The drive cap  55  is mounted to be rotatable relative to the housing  53 , but is flanged (as at  59 ) to be retained axially in position relative to the housing. On its external surface, the drive cap  55  is provided with splines  60 . The drive cap  55  acts as a pivotal mounting for the other of the lid and seat elements  12 ,  13 . The splines  60  on the drive cap  55  ensure that the connection between the two is non-rotatable, ie when the lid or seat element to which it is connected is pivoted, it will cause a corresponding rotational movement of the drive cap  55 . On its interior, the drive cap  55  is provided with a pair of diametrically opposed keyways  61 . 
     The damper  54  here is again of the linear piston and cylinder variety, with a piston (not shown) connected to a piston rod  62  and acting within a cylinder  63  on a damping medium such as silicone, and with a spring (not shown) biassing the piston rod towards its extended position. The free end of the piston rod  62  is arranged to abut against the end wall  58  of the housing  53 . The spring is again not essential here, and the piston rod  62  could be attached to the end wall  58  of the housing  53 . 
     The cylinder  63  has a specially shaped external profile. At its end opposite its piston rod  62 , it has a pair of diametrically opposed keys  64 . The keys  64  are designed to engage the keyways  61  of the drive cap  55 . This ensures that the cylinder  63  and drive cap  55  will rotate together, whilst allowing relative axial movement between the two. 
     The cylinder  63  also comprises a pair of diametrically opposed ribs  65 , each extending around its outer surface. Each rib  65  is shaped with a camming profile that is designed to engage with a respective one of a pair of diametrically opposed lugs  66  provided on the interior of the housing  53 . The ribs  65  and their respective lugs  66  cooperate together in the manner of a cam and cam follower and act to convert rotational movement of the drive cap  55  into axial displacement of the cylinder  63 . With the piston rod  62  abutting against the end wall  58  of the housing  53 , axial displacement of the cylinder  63  will cause extension or contraction of the damper  54 . 
     Preferably, the damper  54  will be designed to produce a damped restrictive force on contraction, but no resistance on extension (it may incorporate a valve in its piston for this purpose). Thus the assembly can be set up to provide a damped resistive force to the pivotal closing movement of the lid/seat element, without resistance to its opening movement. 
     The assembly is arranged so that the hinge damper unit in one of the blocks will provide damping for one of the lid and seat elements, whilst the hinge damper unit in the other block will provide damping for the other element. It will be noted that this conveniently does not require the hinge damper unit to be separately handed: the same device can be used in each case. 
     As with the form of assembly previously described, this form of assembly can be designed to produce a tailored damped resistive force. In particular, the nature of the rib/lug engagement between the cylinder  63  and housing  53  is designed to allow for the possibility of varying the camming profile. With a strictly helical camming profile, for example, this would produce a constant amount of axial displacement of the cylinder  63  per degree of rotation of the drive cap  55 . If the camming profile is designed to increase progressively from the helical, then this would produce an increasing amount of axial displacement per degree of rotation. Also, the starting point of the camming profile could be adjusted in order to delay the onset of the axial displacement until after a certain amount of rotation. Other variations of the camming profile are of course possible to allow a wide range of different solutions tailored to suit different applications. 
     The motion converting mechanism described above could be embodied in a number of different ways. For example, rather than using the form of external ribs extending out from the surface of the cylinder  63 , the camming profile could instead be provided in the form of grooves or cut-aways formed in the surface of the cylinder. An example of this alternative form is seen in  FIG. 7 . Here, a pair of diametrically opposed rebates  70  is formed in the outer surface of the cylinder  63 . The housing  53  here is formed with a pair of diametrically opposed lugs  71  which extend into its interior and engage complementarily with respective rebates. By carefully profiling the shape of the rebates  70 , the arrangement can be designed to produce the desired amount of movement conversion to produce damped resistance tailored to suit movement of the lid/seat elements. 
     It will be understood that the various cam and cam follower formations described above which act as the movement converting mechanisms could equally well be provided the other way round on their respective components. For example, the profiled rebates of the  FIG. 7  example could be provided on the housing, rather than on the cylinder, with the lugs in that case being provided on the cylinder, rather than on the housing. 
     It will be appreciated that the assemblies described above are suitable for use in other applications, including for example in vertical alignment for hanging doors. In that case, the assemblies could be used in the manner of a rising butt hinge and provide damping to the movement of the door as it falls and closes under the force of gravity. Alternatively, the assemblies could be used in the manner of a normal swinging hinge and provide a damped resistive force to the closing movement of the door.