GB2149447A - Latching mechanism for pivotal flap - Google Patents

Abstract

The latching mechanism, particularly for a vehicle fuel tank cover flap (which may incorporate a cap for the filler pipe itself), is electrically actuated, a catch formation (17) of the pivoted flap (15) being engaged by a spring loaded plunger (32) to retain it at the closed position, the plunger being withdrawn to free the flap when a solenoid (31) is energised through a circuit operated by a switch (26) which is actuated by inward pressure on the flap moving it beyond the closed position. The mechanism may be connected to a central door locking system of the vehicle so that the flap can only be released when the doors are unlocked. <IMAGE>

Description

SPECIFICATION Latching mechanism for pivotal flap This invention relates to a latching mechanism for holding a pivotally mounted flap in a retained position and has for its objectthe provision of an electrically operated latching mechanism suitableforthe petrol flap orcoverofthefueltankofa motorvehicle.

According to the present invention there is provided a latching mechanism for holding a pivotally mounted flap in a retained position, comprising an electrical actuator, an engagement element movable by the actuator and positioned for engagement with a member mounted on, or a part of, the flap, and switch means so arranged that, when it is required to release the flap, pressure applied to the flap is effective to operate the switch means to cause the actuator to move the engagement element into a position in which the flap member is released.

Operation ofthe actuator is preferably controlled by a control circuitforming part ofthe vehicle locking unlocking control system with the arrangement such that release of the flap member can only be effected when the lockinglunlocking control system is in its unlock mode.

In one embodiment of the invention, the switch means is arranged so asto be operated bytheflap when the latter is moved back to the position in which it is to be retained, such operation of the switch means being effective to cause or allow the engagement element to move into the flap retaining position. In this case, after release of the flap, the electrical actuator may be maintained energised until the flap is moved back to the position in which it is to be retained whereupon the actuator may be de-energised to allow the engagement elementto return to its flap-retaining position by spring-loading.

In a second embodiment, the engagement element may be in the form of an automatically-operating spring-biassed detentwhich allows flap movement into its retained position but has to be retracted by means of the electrical actuator to permitflap release, the arrangment preferably being such that only alternate operations of the switch means are effective to operate the electrical actuator. In this way, it is unnecessaryto maintain the electrical actuatorener gised for any appreciable length of time because relatching oftheflap is achieved mechanically and inadvertent operation ofthe switch means during closure of the flap does not affect the intended functioning ofthe mechanism because the electrical actuator is only energised on alternate operations of the switch means by the flap.

The flap mayfit over a filler cap which is mounted on the neck of the vehicle filler pipe. Alternatively the flap may itselffunction as the cap and include sealing means which seal againstthetop ofthe neckofthe filler pipe to effect sealed closure thereof.

In that forum in which the flap fits over a filler cap, the flap preferably carries a striker which is positioned so that, when the flap is pressed or closed, the striker engages a spring loaded plungerto actuate the switch means. In this construction the actuator may be in the form of a solenoid, the plunger of which is positioned for movement into blocking relationship with the striker.

In thatform in which the flap itselffunctions as the filler cap, the flap preferably includes a wall formed with a generally key-hole shaped slot which is arranged to cooperate with the plunger of a solenoid, said plunger being formed with a portion of reduced diameterwhich can pass through the neck ofthe key-holeslotwhereasthe main bodyofthe plunger is retained within the circular portion ofthe key-hole slot.

Preferably the arrangement is such that the engagement element when operative blocks the path of travel of said member in the flap opening direction but allows limited flap movement in the opposite direction whereby switch operation can be effected and any side load acting on said engagement element is relieved and allows retraction ofthe engagement element to be achieved with a relatively small energising current.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure lisa sectional view illustrating one form of petrol flap latch in detail; Figure 2 is an enlarged view of part of the flap latch shown in Fig. 1; Figure 3 illustrates diagrammatically anotherform of petrol flap latch; and Figure 4 is a front view of the flap latch shown in Figure 3.

The petrol flap latch shown in Figures 1 and 2 ofthe drawings comprises a main body 10 formed as a plastics moulding which is mounted on the rearwing 11 of a vehicle by fixing bolts (not shown) and a flap 15 which is pivoted to the wing 11 at pivot 16 and may be spring-loaded to its open position. A fuel-resistant seal 13 is located between the moulded body 10 and the wing 11.The main body 10 carries location pegs 14 in orderto approximately position it relative to the aperture in wing 11 during installation. The main body loins provided with an opening 1 Oa forfitment to the petrol filler pipe ofthe vehicle.

A striker 17 is attached to the flap and comprises a threaded shaft portion 18which is received in a threaded socket in the flap 15 and is loated in its desired position of adjustment by means of locknuts 19. Aseal 50 is attached to the striker 17 for sealing engagementwith annular shoulder 52 when the flap is closed. The main body 10 isfinally locked into its correct positional setting when the striker nose portion 20 has been centralised in the bore 33 of the solenoid housing 29.

The shaped head formation 20 of the striker 17 atthe end of its travel i.e. during the final stages of the The drawing(s) originally filed was (were) informal and the print here produced is taken from a later filed formal copy.

The claims were filed later than the filing date within the period prescribed by Rule 25(1) of the Patents Rules 1982.

closing movement ofthe flap 15, engages with the head of plunger 21.The plunger 21 passes through a bearing aperture in a portion 22 ofthe moulded plastic solenoid housing 29. The plunger21 is acted upon buy a helical compression spring 23 which acts between the portion 22 ofthe moulded housing 29 and the underside ofthe plunger 21.

Upward travel ofthe plunger 21 is limited by means of a lock washer 25 which is mounted on the plunger 21 and is positioned to engagethe underside of portion 22. The lower end portion ofthe plunger21 engages a switch 26 mounted on a printed circuit board 27. The circuit board 27 is fulcrummed at 24 and is supported at the opposite end by a spring-loaded bush 28 so thatthe circuit board can tiltto a limited degree aboutthefulcrum 24when engaged by the plunger 21.

The housing 29 accommodates a solenoid 31 and the printed circuit board 27 carries electronic components (not shown) controlling operation ofthe solenoid 31 and hence the petrol flap latch mechanism.

The solenoid 31 has a plunger32 which is springloaded towards its projecting position in which it projects through an opening in a wall ofthe bore 33 of the housing 29 for engagement with the head formation 20 such that, when the flap is closed and the striker 17 and solenoid plunger 32 are in the positions indicated in Figures 1 and 2, the plunger 32 lies in the path of movement of the head formation 20 ofthe striker 17 and the flap 15 is retained in its closed position.

A step 34 projects upwardly within the solenoid housing 29to provide an end location forthe solenoid 31 so that when the housing is fitted within the main body moulding 10 effective location of solenoid 31 is achieved. An overide slide 36 isjournalled in the top of the solenoid housing 29 and is so disposed that a projecting lug 37 impinges on circlip 38 when the slide is moved horizontally rearwards by means offinger grip 35. The slide 36 is accessible from within the boot of the vehicle so that, in the event of failure of the solenoid oranyotherfailure ofthe petrol flap latch mechanism, the petrol flap can be released by moving the slide 36to withdraw the solenoid plunger 32 manually against the action ofthe solenoid spring 39.

Asealing strip 40 guards against petrol vapour entering the boot area of the vehicle and also provides sufficientfriction to retain the slide 36 and hence the solenoid plunger 32 withdrawn whilst installation in the vehicle is proceeding.

The petrol flap latch mechanism is preferably connected to the vehicle door locking/unlocking control system so that, when the doors ofthe vehicle are locked, energisation of the solenoid 31 cannot be effected whereas, when the doors,of the vehicle are unlocked, energisation ofthe solenoid 31 can be effected to permit opening of the petrol flap. Thus, when the vehicle doors are locked and manual pressure is applied to the portion of the flap 15 adjacentthe striker 17, the switch 26 is actuated but no signal is applied to the solenoid 31. When the vehicle doors are unlocked, the control circuitry on the printed circuit board receives an "unlock" signal andresponds to said signal to permit opening of the petrol flap 15.Thus, when theflap 15 is pressed manuallyto actuate the switch 26, the solenoid 31 is energised for a predetermined time and the plunger 32 is withdrawn from engagementwith the headformation 20 ofthe striker 17. The flap I Swill then move underthe action of its spring loading into its open position.

In one form ofthe embodiment of Figures 1 and 2, after a predetermined time interval, the control circuit operatesto reducethe powersupplied to the solenoid such that it isjust sufficient to hold the solenoid plungerwithdrawnfrom engagementwith the head formation 20 of the striker 17. Atthe same time the control circuit records a change from a 'latched' mode to an 'unlatched' mode.

When the petrol flap 15 is subsequently closed i.e.

afterthe fuel tank has been refilled, movement ofthe striker 17 beyond its closed position effects displacement ofthe plunger 21 against action ofthe spring 23 and thus operates switch 26. Because, however, the control circuit is now in its unlatched mode, operation ofthe switch 26 does notserveto energise the solenoid 31, instead it causes the control circuitto release the solenoid by turning off the holding current.

Atthe sametime it records a changefrom an unlatched mode to a latched mode. Thus for as long as the door locking mechanism is in its 'unlocked' condition only alternate operations of the switch 26 causethe solenoid to become energised.

In the version described above, the solenoid plunger32 is held retracted pending return oftheflapto its closed position. However, the solenoid plunger is arranged to act as a mechanical spring-loaded detent for the purposes of relatching the flap when for example there is a loss of electrical power and if the solenoid malfunctions.Thus, the head 20 is provided with a shaped surface 54to provide a camming action with the end of the solenoid plunger32 so that during pivoting oftheflap 15 back to its closed position, the surface 54 engages the plunger 32 (which, at this time will be held extended bythe spring 39 ifthe solenoid is not operational for any reason) and causes the plunger32to retract until the head 20 clearsthe path of movement ofthe latter whereupon the plunger 32 returns to its extended position in which it engages the shoulder 56 ofthe head 20.

In a modification,the solenoid 31 is used only for flap release and the mechanical detent action of the plunger 32 is relied uponforrelatchingtheflap, thereby obviating the need to supplythe solenoid with reduced level current two hold the plunger retracted. In such a modification, provision is madeto distinguish between operations of switch 26 corresponding to opening or closing ofthe flap. Thus, a bistable electronic latch (not shown) may be associated with the switch 26 such that a first switch operation (corresponding to flap opening) causes the bistable to change from a first state in which solenoid energisation is not effected to a second state which leads to solenoid energisation fora short interval oftime and such that a second switch operation (corresponding to flap closure) causes the bistable to revert two its first stateto prevent solenoid energisation in response to the second switch operation. in this way, itwill be seen that the solenoid can only be energised in response to alternate operations ofthe switch 26.

In most cases, closure of the flap 15 will be accompanied by operation of the switch 26 since the userwilltendto displace the flap beyond its latched position. However, if the flap is closed gently, there may be insufficient overtravel to cause operation of the switch 26 with the consequence that the bistable will remain in its second state. To accommodate this possibility, the vehicle unlocking/locking control system may be arranged to automatically reset the bistableto its first state after each unlocking or locking operation so as to place the flap latching mechanism in readinessfornormal opening. Neverthelessthere may be occasions when no locking/unlocking operation takes place between closure of the flap and a subsequent need to reopen it.In these circumstances, nexttime flap opening is required the userwill need to press the flap twice, once to cause the bistable to revert two its first state and the second time to cause it to change backto its second state to cause solenoid operation. In practice, this is not seen to be a drawback becausethenormal user reaction istotryagain if something does not work first time.

Referring nextto the scheme shown in Figures 3 and 4, this includes a combined petrol flap and cap 61 which is pivotally mounted at 62 on an extension pipe 63 forconnection to the fuel filler pipe, the extension pipe 63 including a mounting for a double-coil solenoid 64 having a plunger65which includes a central portion 66 of reduced diameter and enlarged diameter sections 67. The arrangment is such that, when one ofthe coils 64 is energised, the plunger 65 is moved into a position in which the reduced diameter portion is centrally disposed (see Figure 4) whereas, when the other coil ofthe solenoid is energised, the plunger 65 is displaced to move the reduced diameter 66 portion away from the central position.

The cap 61 includes a cover portion 68 which fits overthe end ofthe extension pipe 63 and carries a sealing member 69 which seals againstthe end face of the pipe 63 when the cap is in its closed position. The cap also includes a wall 70formed with a key-hole shaped slot 72 which is positioned so that, when the cap is in its closed position, the main opening 72a of the slot 72 lines up with the plunger 65.

When the reduced diameter part 66 ofthe plunger 65 is located in its central position, it can pass through the neck ofthe keyhole slot 72 and the cap can be moved into its open position. When, however, the reduced diameter part 66 of the plunger65 is not central and afull diameter section 67 of the plunger 65 is within the keyhole slot 72, the plunger 65 cannot then pass through the neck72b of the slot and the cap is held in its closed position. A switch 74for controlling operation of the solenoid is positioned for engagement by a nose portion 76 ofthewall 70 and functions, in conjunction with a control circuit, in like mannerto the switch 26 of the embodiments described with reference to Figures 1 and 2. It will be noted that the main opening 72a of the slot 72 is oversize (or elongated) relativetothe sections 67 ofthe plunger 65 so asto provide forthe necessary overtravel to allow operation ofthe switch 74 and also relieve side loading on the plunger.

The relief of side loading also applies to the construction shown in Figures 1 and 2 in that the application of manual pressure to the flap relieves the load on the plunger32,wherebythe power required to move the plunger 32 is minimised and consequently a very small solenoid can be employed. The importance of this is that it produces not only a cost saving but also a weight saving.

Claims (18)

1. Latching mechanism for releasably holding a pivotally mounted flap against movement in an opening direction from a closed position comprising an electrically operated actuator, an engagement element movable bytheactuatorand positioned in use for engagement with a catch formation of the flap when at the closed position, and switch means operable by movement of the flap in a non-opening direction past the closed position to cause the actuator to movetheengagementelementfrom a catch engaging position to a disengagement position at which the catch formation is released to free theflap for movement in the opening direction.

2. Mechanism as in Claim 1 wherein the switch means is also operable by closing movement ofthe flap past the closed position so operating the actuator in use for movement of the engagement element from the disengaged position to the catch engaging position.

3. Mechanism as in Claim 2 wherein the actuator is operated bythe switch means in use to retain the engagement element at the disengaged position until the flap is returned to the closed position.

4. Mechanism as in Claim 3 including an electrical control circuit connecting the switch means and the actuator, said circuit operating to reduce the energising powersupplied tothe actuatorto a lower level just sufficientto retain the engagement element at the disengaged position a predetermined time after energisation was initiated to move it from the catch engaging position.

5. Mechanism as in Claim 3 or4wherein the engagement element is resiliently urged to the catch engaging position.

6. Mechanism as in Claim 5 wherein the engagement element operates independently of the actuator to allowthe flap to move to the closed position and engage the catch formation at that position.

7. Mechanism as in Claim 6wherein only alternative operations of the switch means are effective to operate the actuator.

8. Mechanism as in any preceding claim including resiliently loaded means disposed for abutment by the catch formation in use on said movement of the flap past the closed position, said means actuating the switch means.

9. Mechanism as in any preceding claim including an overriding element selectively operable manually for movement ofthe engagement elementfrom the catch engaging position.

10. Mechanism as in any preceding claim wherein the engagement element is a plunger having a reduced diameter portion, and the actuator is a solenoid arranged for axial movement of the plunger between a catch engaging position at which a key-hole shaped slot of the catch formation is retained by said plunger and a disengaged position at which the reduced diameter portion is aligned with said slot so thattheflap is free for opening movement.

11. Mechanism as in Claim 10 wherein the plunger is shaped to allow clearance within the slot so that side loading thereon is relived when the flap is moved past the closed position to operate the switch means.

12. Latching mechanism substantially as hereinbefore described with reference to and as shown in Figures 1 and 2, or Figures 3 and 4 of the accompanying drawings.

13. Avehiclefueltankfillerassemblyincluding a pivotally mounted flap and a latching mechanism as in any preceding claim.

14. AnassemblyasinClaim 13whereintheflap functions as a cap forthefuel tank filler pipe and includes sealing means seating againstthe filler pipe rim to effect closure thereof when the flap is at the closed position.

15. An assembly as in Claim 130rl4whereinthe catch formation of the flap is shaped to provide a surface having a camming action for mechanical displacement of the engagement element when the flap is moved to the closed position.

16. Avehicle including a latching mechanism or fuel tankfillerassembly as in any preceding claim.

17. A vehicle as in Claim 16 having a door locking/unlocking control system with which a control circuit of the latching mechanism is connected wherebywhen said system is in a locking mode the switch means will not operate the actuator.

18. Avehicle as in Claim 16or17 so far as dependent on Claim 9 wherein the overriding element is accessible from within a boot of the vehicle.