TECHNICAL FIELD

[0001] THIS INVENTION relates to a collapsible speed bump assembly and in particular but not limited to a collapsible speed bump assembly for use as an active part of a passive speed bump,

BACKGROUND

[0002] Speeds bumps used to slow traffic are inconvenient to drivers who are already driving slowly.

[0003] Efforts have been made to devise speed bumps that retract or collapse when a vehicle approaches at a lower than a threshold speed or rolls over at a speed lower than a

predetermined maximum. If the vehicle is going too fast the speed bump does not retract.

[0004] In one device an up road sensor is used to effectiveiy time the vehicle from the sensor to the bump. The speed bump is disabled at a set time after the vehicle passes the sensor, if the vehicle arrives too soon the speed bump is still enabled and does not collapse. This device is not self contained and require power to operate.

[0005] Another device uses a piston with a bleed valve and as long as the vehicle speed is below the bleed rate the bump will collapse otherwise it will still provide a bump. This device is self contained and passive but has not been readily adopted.

[0006] The applicant requested an international Type Search under Article 15/5 of the PCT on Australian National Application 2013901284.That search referred to patents specifications US2Q05/G063779 (Yang); US 4,974,991 (Mandavi) and US 2002/0001505 (Bond). [0007] According to US 2005/0063779 (Yang), Yang utilises separation of a pair of magnets if a vehicle strikes the speed bump with such "impulse" that the magnetic force is suddenly overcome by the mechanical force of a wheel striking the speed bump and transmitted down to the magnets through a system of gears. Impulse as a physical quantity relies on a high velocit over a short duration of time to separate the magnets. In addition Yang employs a releasabie means that normally blocks the speed bum collapsing and as long as the magnets remain engaged this reseaSabfe means is moved out of the way to release the speed bump so that it can collapse. There is no time delay related to the wheel engaging the speed bump and the release of the releasabie means since there is effectively a constant coupling between them, Yang effectively operates on the basis of anticipation that the speed will be below the threshold.

[0008] US 4,974,991 (Mandavi) utilises a quite different approach employing "inertia" (but not for a time delay purpose) , being an inherent property of matter to resist motion, by using a pendulum having a toothed block which swings into blocking position if wheel speed is too high. Otherwise the pendulum just swings away and the speed bump collapses.

[0009] In Yang it is the impulse overcoming the magnetic force that is key. Yang is either on or off not unlike a switch. The inertia of the parts involved could be quite low and it all depends on the magnets and the magnetic force involved rather than inherent inertia. Unlike Yang there is no releasabie means, but similar to Yang the speed bump is in a normally released position so there is nothing that has to be released. Rather the engagement of the toothed block is something avoided by the low speed rather than there being a positive release action.

[0010] US 2002/000 505 (Bond) is similar to Yang except springs are used instead of magnets. The many embodiments use calibrated springs where the springs are analogous to the magnets of Yang in so far as the spring force is overcome by the wheel impulse in an overspeed situation and the speed bump remains locked. Similar to Yang and Mandavi, the speed bump is in a normally released condition so there is no releasabie means rather there is a catch that is avoided if the wheel is travelling below the calibration value of the springs.

[0011] interestingly the International Type Search Report was accompanied by a "Written Opinion" which sought to combine Yang with Bond or Mandavi but did not provide any reasoned argument as to how integers ouid be selected and which would be omitted in such mechanically different arrangements and how they could be combined to give rise to the present invention, it is noted that each of Yang, Bond and Mandavt describes a combination where the operation of the speed bump is dependent on the particular mechanisms employed. Each is a combination requiring ail features for operation, in the case of a combination patent the invention will lie in the selection of integers, a process which will necessarily involve rejection of other possible integers. The prior existence of publications revealing those integers, as separate items, and other possible integers does not of itself make an alleged invention obvious. It is the selection of the integers out of, perhaps many possibilities, which must be shown to be obvious.

[0012] It is an object of the present invention to provide an alternative to the prior art, it being appreciated that the above prior art discussion is not an admission as to the "common general knowledge" but is a discussion of "public knowledge".

SUMMARY OF THE INVENTION

[0013] In one broad aspect there is provided a collapsible speed bump assembly having a speed bump that is normally held in a raised position by releasable means that releases the speed bump to collapse if a vehicle is travelling slow enough over the speed bump but the speed bump remains raised if the vehicle is going too fast, the assembly having an inbuilt delay mechanism arising from inherent inertia between a vehicle wheel striking the speed bump and the releasable means releasing the speed bump. If the inherent delay is exceeded then the speed bump will be automatically released by the release means. In a prefered form there is provided a speed bump assembly including a housing adapted to be inserted into a surface where a collapsible speed bump is desirable, a collapsible speed bump held in the housing and being adapted to collapse as an under speed vehicle passes over the speed bump, the speed bump being biased to a normally raised position and there being releasable means comprising retractable blocking means being adapted to block collapse of the speed bump as an overspeed vehicle passes over the speed bump. Preferably, the collapsible speed bump assembly has an effective inertial load used to lag operation of the collapsible speed bump to a predetermined time after engagement by a vehicle wheel. In a further embodiment the inertial load is provided by a siidabie load. [0014] in a preferred form there is provided a collapsible speed bump assembly employing a retractable speed bump member, the speed bump member having a downwardiy projecting flange with a leading edge, the leading edge being adapted upon downward movement of the speed bump member to strike or just miss a top surface of a shiftab!e and retractable bar or stop block, the hit or miss depending upon whether or not the block has had enough time to retract by reason of a vehicle wheel striking the speed bump and providing the motive force for retraction of the block. Preferably, in the event the leading edge engages the block before it retracts then the weight of the vehicle will ensure it does not retract and the speed bump will operate in its raised position, in the event the vehicle is going slow enough the block will have time to retract and the leading edge will pass by the block and the speed bump will collapse. Preferably, the block is spring biased to an extended position. The spring bias may be adjustable. In one embodiment a lever arm operates as a speed bump follower and inturn has a return spring to return the speed bump to its raised position. Typically, where a retractabl block is employed a guide and guideway connects the block to the speed bump assembly via a rotatable link to change rotation of the speed bump to linear movement of the block.

[0015] "Underspeed" and "overspeecT refers to vehicle speed being above or below the a threshold speed setting up to which the speed bump will collapse.

[0016] In another application of the invention a passive speed bump has collapsible sections so the passive speed bump will have two gaps and these gaps will be fitted with collapsible speed bump assemblies according to the present invention which are made conspicuous. As a vehicle approaches the driver may choose to direct the vehicle slowly over the collapsible sections and benefit from the ride by avoiding a bump. Of course if the driver travels too fast the bump will not be avoided.

[0017] The housing may be any suitable rigid support that is sufficiently robust for insertion into a roadway. Typically, the housing is wide enough that it may be used in tandem with another adjacent housing to cater for various wheel spacing and tyre widths for various vehicles. It may be much wider and could be in some cases the full road width although this would be more expensive. [0018] Typically, vehicles approach from upstream so preferably, the housing has an upstream entry end, a downstream exit end, an intermediate collapsible bump seat section and an outer frame around the seat section.

[0019] The collapsible speed bump preferably comprises a pair of hinged together plates pivotally coupled to the housing so that the plates may flatten onto the seat section. Preferably, the pivotal coupling to the housing is at or adjacent the entry end.

[0020] The retractable blocking means preferably blocks movement of the collapsible speed bump and typically includes a collapsible speed bump movement arrester means projecting into the seat section in a raised position to prevent the collapsible speed bump from flattening. This means that in this embodiment there is some limited movement of the collapsible speed bump but that movement is arrested, in the sense of being checked or stopped if the conditions for collapse are not present.

[0021] The arrester means may comprise a pin, plate or other blocking means that blocks any part of the collapsible speed bump from properly occupying its flattened seated position. The degree of arrest may vary from almost 100% to other levels depending upon design

requirements. In one preferred form the collapsible speed bump is able to move slightly before it engages the arrester means. If the arrester means has not already retracted then its engagement by the collapsible speed bum prevents retraction. Thus, the vehicle provides the generative force for keeping the speed bump raised. Thus, the time it takes the speed bump to engage the arrester means sets the vehicle speed limit. Preferably, the arrester means is located in the seat section downstream of the collapsible speed bump, in one example the arrester means comprises projecting fingers spaced across the housing downstream of a leading edge of the collapsible speed bump. The upstream surface of the fingers runs parallel to the leading edge. So that there is controlled engagement of the fingers and the leading edge the leading edge movement is typically is constrained by a guide traveling in a guideway.

[0022] The retractable blocking means may be controlled in any way but preferably further includes a mechanical retraction mechanism, typically located under the housing and includes various levers and springs and more preferably uses as its generative force the load of the passing vehicle for its operation. Thus it is preferred that the collapsible speed bump has a lever arm extending downward. The arrester means preferably has a lever arm extending

downwards, the lever arms having springs biasing the respective bump and arrester to raised positions.

[0023] In applications where the collapsible speed bump is exposed to weather it is preferred that it be located in a protective cover. More preferably, the protective cover is a flexible bladder surrounding the whole assembly.

[0024] In another preferred form the motion of the coliapstbie speed bump may be damped by a suitable damper which might be an air spring or piston with a high bleed rate so that the collapse is more controlled and more regulated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] in order that the present invention may be more readily understood and put into practical effect reference will now be made to the accompanying drawings which illustrate preferred embodiments of the invention and wherein:-

Figure 1 is a drawing of a passive speed bump with two collapsible speed bump assemblies set at a wheel spacing;

Figure 2 is a is a top view of a typical speed bump assembly ;

Figure 3 is an underside view ;

Figure 4 is a slide view;

Figure 5 is a drawing showing the underside of a typical housing;

Figure 8 is a drawing showing the housing from the top;

Figure 7 is a drawing showing typical plates used for the collapsible speed bump;

Figure 8 is a drawing showing a typical arrester means and its lever arm;

Figures 9 and 10 are drawings showing downstream and upstream aspects of a typical speed bump assembly;

Figures 11 and 12 are diagrams illustrating how the speed bump of the drawings Figures 1-10 operates;

Figure 13 and 14 are additional optional features that may be applied to the speed bump assembly;

Figure 15 is a schematic drawing serving to illustrate another embodiment also using a time delay inherent in the system due to inertia arises from shifting a load; and

Figures 16 and 17 are a side view and a top view respectively of an embodiment similar to Figure 15 employing a shiftable load to delay collapse of the ramp.

METHOD OF PERFORMANCE

[0028] Referring to the drawings and initially to Figure 1 there is illustrated a roadway area 0 having a speed bump 11 extending across the roadway. The speed bump 10 has passive sections 12, 13 and 14 and collapsible sections 15 and 16. The collapsible sections are made conspicuous by the markings applied to the passive sections and the patterned surface of the collapsible sections. Each of the collapsible sections comprises a collapsible speed bump assembly according to the present invention,

[0027] Referring to Figure 2-10 a collapsible speed bum assembly 17 is shown and comprising a housing 8, a collapsible speed bump 19 hinged to the housing at an upstream end 20 at hinge 21 and in Figure 2 is shown in a raised position. The speed bump 19 comprises an upstream plate 22 and a downstream plate 23 hinged together at hinge 24. The plates 22 and 23 move in a downstream direction as a vehicle wheel strikes plate 22. The housing 18 has a seat section 25 to accommodate the plates, the seat section extends from the hinge 21 downstream to the inner edge 26 of the cross frame member 27 so it is shaped to match the flattened plates 22 and 23 which fit into it. The plate 23 has a leading edge 28 that moves downstream as a vehicle wheel strikes plate 22 but blocking the leading edge are three projections 29, 30 and 31 which project through corresponding holes 32, 33 and 34 in the housing 18 and serve to arrest this movement when the leading edge strikes them. Only by retraction of the projections 29, 30 and 31 will the speed bump collapse.

[0028] Referring to Figures 3 and 4, in Figure 3 the assembly of Figure 2 has effectively been turned upside down and arranged so that the speed bump is flattened, whereas in Figure 4 the speed bump is raised. It will be appreciated that the speed bump 19 is normally biased to the raised position so Figures 3 and 4 serve to illustrate the relative position of the parts in the collapsed and raised positions respectively.

[0029] The housing 18 includes welded together angle sections 35, 36, 37 and 38 a cross member 39 of angle and an arrester aperture plate 40. An arrester plate 41 has a iever arm 42 and pivots on an axle 43 extending between axle mounts 44 and 45. The plate 22 has a lever arm 46. Springs 47 and 48 extend between the arrester Iever arm 42 and a fixed mount 49 and the iever arm 46 respectively,

[0030] As can bee seen in Figure 4 the lever arms 42 and 46 are substantially parallei whereas in Figure 3 lever arm 42 has hardly moved while Iever arm 46 is almost vertical. This is because in Figure 3 a stop 50 has prevented the edge 51 of plate 41 from moving further.

[0031] Referring now to Figures 11 and 12 the operation of the assembly will be described.

Figure 11 illustrates operation in an underspeed situation where the speed bump collapses and completely flattens while Figure 12 illustrates operation in an overspeed situation.

[0032] in Figure 11 the vehicle wheel 52 engages plate 22 such that the leading edge 28 begins to move in the downstream direction as shown by the arrow 53. As the iever arm 46 begins to move the inertia in the system creates a delay between the movement of Iever arm 46 and movement of iever arm 42 and the retraction of the projections 29, 30, 31. The arrester plate hits stop 50 and the plates 22 and 23 flatten as the wheel 52 passes over.

[0033] in Figure 12 the inertial delay is too long and the projections 29, 30, 31 have been "caught" by the leading edge and the spring 48 is only designed to be able to overcome the return spring 47 so it simply extends marginally in accordance with the movement of the leading edge.

[0034] Figures 13 and 14 illustrate option additions in Figure 3 the leading edge 28 has a guide rod 54 which travels in a guideway comprising a channel or track 55 on opposite frame members 36 and 38. [0035] in the case of outdoor operation the assembly may be contained in a bladder or other flexible weatherproof enclosure 56 with an expansion space at 57 as shown in phantom so that the bladder may expand into this space as the bump flattens.

[0036] Referring now to Figure 15 there is illustrated in schematic a collapsible speed bump assembl 58 having a housing 59, a speed bump 60 and a retractable blocking means 61 comprising a weight 62 adapted to slide within the housing. The weight is mounted on springs 63 and 64 and will slide to the right in response to a vehicle wheel engaging the speed bump 60 due to lever arm 65 being attached to spring 64. Depending upon the inertia of the weight there will be a delay moving the weight out of the way of the leading edge 66 of the ramp and the slower the vehicle is moving then the edge 66 wilt clear the weigh as it moves out of the way and the speed bump will be released to collapse, if the speed is too high the block 61 will not allow the speed bump to flatten onto the seat 67. A ramp re-erection spring is shown at 68 and after a vehicle has passed below the desired speed the springs will restore the arrangement to the equilibrium position illustrated in Figure 15.

[0037] Referring now to Figures 16 and 17 there is illustrated a further embodiment, being a collapsible speed bump assembly 69 employing a retractable speed bump member 70, the speed bump member having a downwardly projecting flange 71 with a leading edge 72, the leading edge being adapted upon downward movement of the speed bump member to strike or just miss a top surface 73 of shiftable and retractable bar or stop block 74, the hit or miss depending upon whether or not the block 74 has had enough time to retract by reason of a vehicle wheel striking the speed bump 70 and providing the motive force for retraction of the block, in the event the leading edge engages the block before it retracts then the weight of the vehicle will ensure it does not retract and the speed bump will operate i its raised position causing an irritating bump, in the event the vehicle is going slow enough the block will have time to retract and the leading edge will pass by the block and the speed bump will collapse.

[0038] As illustrated in the previous embodiments, while the means by which the inertia! delay is set up mechanically, the particular mechanical arrangement is not part of the broadest form of the present invention, rather it is the inertial delay occasioned by the setup. That is the delay from vehicle wheel contact to the collapse of the speed bump, arising from inherent inertia in the speed bump assembly when the vehicle speed is below the predetermined level giving rise to release of the speed bump so that it can collapse.

[0039] in the present mechanism the speed assembl is fashioned primarily from steel components but may be made for any suitable material as would be sufficiently robust for the purpose. It will be seen from Figure 17 that there a similar components set bilaterally across the assembly so where these components are mirrored the same numerals have been used for clarity.

[0040] The assembly has an outer box like housing 75 having two shafts 76 and 77 extending across the housing betwee side wall plates 78 and 79. The speed bump 70 includes as a wheel plate 80 adapted to move between the raised position shown and a collapsed position. Shaft 78 is a speed bump hinge shaft supporting for pivot the speed bump wheel plate 80 and a wheel plate stop plate 81 which are rigid together to move in concert about the shaft 76. As shown in Figure 16 when the speed bump is in the raised position the stop plate 81 is abutting a wheel plate return stop 82 which is welded to base piate 83. The plate 81 has spaced tabs 84 which carry return rods 85 connected to the block 74. The rods 85 travel inside return rod guide tubes 86. Thus when a wheel contacts the wheel plate 80 the tendency of the arrangement is to pull the block 74 in the direction of arrow 87 out of the way of the edge 72.

[0041] The second shaft 77 is a cam lever shaft and this has rigid cam levers 88 arranged as wheel plate followers with ends 89 in contact with underside 90 of plate 80. The cam lever shaft is journaled in bearings at 91 , 92, 93 and 94 and extends below the shaft with at least one lever 88 having a crank arm 95 connected to stop block 74 adjustment spring 96. A spring adjuster nut 97 is used to adjust the spring to regulate to spring tension that is transmitted through the cam lever 88, piate 80, stop plate 81 and rods 85 to the sto block 74 to fine tune the inertia! delay. The block 74 is suitably mounted to slide and has a stops 98.

[0042] In operation a travelling wheel of a vehicle engages the raised plate 80 and causes the wheel force to be applied progressively to the wheel plate, as the wheel plate is loaded it will start to pivot, the spring 96 will resist this while at the same time the stop block will have its inertia resist it being slided out of the way, this inertial time delay means that the stop block will remain in place if the wheel force is applied too fast and the stop block wiil be engaged by the edge 72 and the speed bump will not collapse. If the wheel force is applied slow enough the stop block will retract and the speed bump will collapse. After the wheel has passed spring 96 will return all parts to the operative speed bum raised position of Figure 16.

[0043] Whilst the above has been given by way of illustrative example many variations and modsficattons will be apparent to those skflled in the art without departing from the broad ambit and scope of the invention as set out in the appended claims.