EP0003350A1

EP0003350A1 - Latch mechanism

Info

Publication number: EP0003350A1
Application number: EP79100194A
Authority: EP
Inventors: Pierre Jean-Marie Rey
Original assignee: Eaton SAM
Current assignee: BorgWarner Transmission Systems Monaco SAM
Priority date: 1978-01-23
Filing date: 1979-01-23
Publication date: 1979-08-08
Also published as: AU4349079A; GB1600691A; ES477058A1

Abstract

A latch mechanism comprising a first member which is adapted to engage with a second, resiliently displaceable member (22, 24), characterized in that the engaging portions of the members being so formed that a force applied to the members in a direction tending to engage them can cause resilient displacement of the second member (22, 24) to permit engagement of the latch mechanism, first, manual means (34) for disengaging said members (18, 22, 24), and additional means (44,46,48) for moving one of the members relative to the other when they are in engagement, so as to disengage the members, whereby the members are disengageable both by using said first means (34) or by operation of said moving means (44, 46, 48).

Description

This invention relates to latch mechanisms which are suitable for many different applications but in particular for latching the lid of a dispenser for washing material, such as soap powder or liquid, in a washing machine such as a clothes washing machine or a dish washing machine.
Such dispensers are filled with washing material such as soap powder and then the lid of the dispenser is closed. It is most desirable for this closure to be done simply by manually pressing the lid into its closed position and for the latch to retain it there. At the desired time during the cycle of operation of the machine, the lid of the dispenser is automatically opened by means of a solenoid which releases the latch mechanism under the control of a programmed control device in the machine. It is possible that an operator may accidentally close the lid of the dispenser without having put washing material such as soap powder into it. It is then desirable that the operator should be able to open the dispenser lid manually.
The present invention provides a latch mechanism particularly suited for application to such dispensers, which can be manually closed and which has two different modes of opening, one of which is well suited to being automatically carried out for example by means of an electromagnetic actuator, but which could alternatively be carried out manually, and the other of which is easily done manually so that, for example, the latch when applied to a dispenser can be readily re-opened manually by the operator to introduce washing material such as soap powder, which the operator had previously forgotten to introduce.
From a broad aspect, the invention provides a latch mechanism comprising a first member which is adapted to engage with a second, resiliently displaceable member, the engaging portions of the members being so formed that a force applied to the members in a direction tending to engage them can cause resilient displacement of the second member to permit engagement of the latch, first, manual, means for disengaging said members, and additional means for moving one of the members relative to the other when they are in engagement, so as to disengage the members, whereby the members are disengageable both by using said first means or by operation of said moving means.
Preferably said one member is rotatable to disengage it from the other member, this form of movement being well adapted for.automatic operation by an actuator, or for manual operation.
When said one member is rotatable, then preferably it includes at least one shoulder which engages with the other member when the one member is in one angular position but not when the one member is rotated to another angular position.
When the means for moving the one member comprises an electromagnetic actuator, operation of which rotates said one member, then preferably biassing means is provided for biassing said one member into a position for engagement with the other member, the electromagnetic actuator when actuated operating against said biassing means to move said one member into a disengaging position. In this way, when the actuator is in its normal unener- gised condition, the rotatable member will always be biassed into a position where the latch can be engaged simply by manually forcing the two members of the latch into engagement with each other.
The invention involves further advantageous features and these will become apparent from the description of various embodiments which follows.
In order that the invention may be more clearly understood embodiments will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:-

Figure 1 shows a washing material dispenser for a washing machine, embodying the present invention;
Figures2 and 3 show the head of a rotatable latching member of the Figure 1 embodiment, when in the engaged and disengaged positions, respectively;
Figures 4 and 5 show an alternative form of head for the rotatable latching member; again in the engaged and disengaged positions respectively;
Figure 6 shows in detail an alternative arrangement for manually opening a latching mechanism;
Figure ? shows a further alternative arrangement for the same purpose;
Figure 8 shows part of a lid which may be employed in the Figure 1 embodiment and includes various surface details and a modified latching arrangement; and
Figure 9 shows a cross-section on the line IX-IX of Figure 8.

Referring to Figure 1, there is shown a washing material dispenser for a washing machine, which includes a container portion 2 (shown partly cut away for clarity, but with the remainder of the container portion indicated approximately in broken lines) and a lid. 4 which in the position shown closes the open side of the container portion 2. The container portion 2 is fixedly mounted to a part of the washing machine, for example by being riveted by rivets such as 6 to a part 8 of the washing machine. The lid 4 is hinged to the washing machine on one side by means of a hinge pin 10 which passes through a lug 12 integral with the lid and through a lug 14 on another fixed part 16 of the washing machine. A similar hinging arrangement is also provided at the other side of the lid, but this is not shown in detail, only the corresponding lug 14' being visible in Figure 1.
In Figure 1, the dispenser is shown with the lid facing downwards, but this is done cnly to clearly illustrate its detail. In practice, the dispenser would commonly be fitted in a quite different position, for example in a dish washing machine it would normally be fitted into the door of the machine so that when the machine door was opened downwardly, the lid of the dispenser would face vertically upwards, enabling easy introduction of powder into the container 2. When the machine door was closed into its vertical closed position then the lid of the closed dispenser would also lie in a vertical position.
In Figure 1 the lid 4 is shown held in its closed position by a latch mechanism which comprises a first member in the form of a shaft 18 rotatably mounted in a mounting 20 fixed to the body portion 2, and a second member which is resiliently displaceable and comprises the two arms 22 of an elongated U-shaped wire spring 24 which is'secured to the lid 4 by being inserted through pairs of holes in mounting lugs 26 fixed to the inner surface of the lid 4. The shaft 18 has a head 28 which has notches 30 on opposite sides thereof. Only one notch 30 can be seen in Figure 1 but both are shown in detail in Figure 2, where it can be seen also that the spring arms 22 are engaged in these notches thereby holding the lid in the closed position. The most important parts of the notches for the purpose of this retention of the lid are the shoulders formed by the lower walls of the notches (as viewed in Figure 2), which lower walls are indicated at 32.
From the latched closed position the lid 4 can be opened manually by pulling downwardly (as viewed in Figurel) on the lid 4, for instance using a handle indicated at 34, so that the shoulders 32 which have a sloping configuration can push apart the spring arms 22 until these arms have ridden over the shoulders in the direction of the arrow A in Figure 2 at which time the lid is freed for opening in the direction of arrow B in Figure 1. Opening is initially assisted by the spring arms 22 pressing inwardly on the tapering part of the head 28 and then also by a spring 36 which is mounted on the hinge pin 10 and has one end contacting a pin 38 fixed to a fixed part 40 of the machine and the other end pressing on the lid 4 and biassing the lid in the opening direction, so as to normally hold the lid 4 open when it is not latched.
From the open position, the lid can be manually closed simply by pressing it back into the closed position so that the spring arms 22 ride over and are spread apart by the rounded and tapered leading end. of the head 18 until the spring arms 22 snap in behind the shoulders formed by walls 32 :of the notches 30. The sloping shape of these walls also ensures that the inward forces applied to them by the spring arms 22 have a tendency to draw the lid 4 tightly into its fully closed position.
As already referred to, at a point during the cycle of the machine it is desired to open the lid 4 automatically in response to an electrical signal. The electrical signal is applied to the terminals 42 of a solenoid 44 which may for example be fixed to the container portion 2 or might be fixed to another part of the washing machine. In response, the solenoid draws in its actuator rod 46 in the direction of the arrow C. The end of the rod 46 is engaged with the end of an arm 48 fixed on the rotatable latching shaft 18, and consequently operation of the solenoid rotates the shaft 18 clockwise against the bias of a spring 50 which encircles the top end of the shaft 18 and has its ends retained, one against the arm 48 and the other against the retaining pin 52 fixed on the container portion 2.
As shaft 18 rotates the spring arms 22 become; spread apart because the diameter of the head 28 is less measured between the troughs of the notches 30 than it is measured in the perpendicular direction, until eventually the position shown in Figure 3 is reached where the spring arms are clear of the notches. At this time the forces of the spring arms 22 on the tapering sides of the head 28, and also the force exerted by the spring 36, cause the lid 4 to move to its open position so that any powder in the container portion 2 can be released.
When the solenoid 44 is de-energised the spring 50 rotates the shaft 18 anti-clockwise back to its original position and the actuating rod 46 of the solenoid is extended.
From this open position, the lid 4 can then be closed by manually pushing it back to the closed position until the latch re-engages as already described with reference to Figure 2.
Although solenoid operation has been described, it should be appreciated that it would be possible, for example, for the upper end of shaft 18 to project through the front of the door of a dish washing machine and to carry an external handle, so that release of the latch and opening of the lid 4 could be effected from outside the machine at any desired time by turning the handle and hence turning the shaft 18 to cause the latch to release in the manner already described. Many other modes of operation are possible, including direct mechanical operation of shaft 18 from the timer of the machine.
Figures 4 and 5 show an alternative form for the head of the rotatable shaft 18. The view of Figure 5 is taken at right angles to the view in Figure 4, so that it will be appreciated that the head 28 is flat on two sides 54 but is tapered on its other two sides 56. Above the sides 56 there are formed two opposed notches 58 corresponding with the notches 30 and having shoulders 60 corresponding with the shoulders 32. With this construction, the effective diameter of the head does not increase as it is turned to release the latch and consequently the spring arms 22 do not have to be forced apart when turning it, so that the torque required to turn the shaft 18 is reduced, enabling the use of a lighter duty solenoid 44. At, or even before, the position shown in Figure 5 where the shaft 18 has been rotated tnrough a right angle, the arms 22 become completely free from the notches 58 and from the remaining portion of the head, so that the lid 4 is free to be opened by the spring 36.
In Figure 6 there is shown a shaft 18 of modified form having a head 28 which is rounded at its leading end, has flat sides and has shoulders 62 which are substantially at right angles to its axis. It will be appreciated that the form of the head 28 enables the head to spread the arms 22 of the spring 24 when the lid is closed, thus enabling easy manual closure of the lid, and the flat sides of the head 28 enables the latch to be released by rotation of the shaft 18 as before. However, the perpendicular shoulders 62 prevent the latch from being released by manually pulling on the lid.
To enable manual opening of the lid, a push-button generally indicated at 64 is provided. The lid itself is 'not shewn in Figure 6, for the purpose of clarity, but it would lie in a plane between the head 28 of shaft 18 and the upper portion 66 of the push-button, so that the two arms 68 of the push-button will extend through apertures in the lid. The push-button 64 is retained in that position by four lateral projections 70 engaging under the arms 22 of spring 24. The push-button 64 is provided with angled camming surfaces 72 such that when the button is depressed these surfaces force apart the arms 22 of spring 24, thus enabling the spread spring to pass over the head 28 so that the door can be opened.
Figure ? shows an alternative arrangement in which the shaft 18 has a similar head 28 and shoulders 62 to those shown in Figure 6 but manual disengagement is achieved by rotating a central pivoted member 74 so that a pair of lugs 76 projecting from member 74 push spring arms 22 away from each other, thus again releasing the head 28 from behind the spring arms. The member 74 may be pivotally mounted on the outside of the lid with the lugs 76 extending through suitably shaped holes in the lid so as to reach the spring 24 beneath the lid. Alternatively, member 74 may be mounted inside the lid and a suitable control shaft for turning it may extend out through an aperture in the lid.
Figure 8 shows a plan view of that part of the lid 4 which is nearest the viewer, as seen in Figure 1, and with some additional features. On its internal surface the lid is provided with a peripheral flange 78 and two more inwardly located ribs 80 and 82 between which is seated a resilient (for example, rubber) seal 83. It will be appreciated that the seal 83 is located so as to co-operate with the edges of the walls 84 of the container portion 2 of the dispenser, and the seal 83 will, of course, extend all the way round this container portion so as to provide a seal between the contents of the container portion and the interior of the washing machine.
The spring 24 is located between rib 82 and rib (flange)78 and is retained by bridge portions 86 and 88 which extend between these two ribs, an abutment 190 also being provided to prevent endwise movement of the spring 24. A pair of projections 90 extend towards each other from ribs 78 and 82 to contact the arms of spring 22 near their free ends.
In Figure 9 this construction is shown cooperating with a shaft 18 having a head 28 of the type shown in Figures 6 and 7. It will be appreciated, on viewing Figure 8, that when the lid is being closed the head 28 will spread the spring arm 22 apart and the arms will bow about fulcrums formed by the projections 90 at the left end and about the fulcrum formed by the joining of the two arms at the right end. For this form of flexing, the length of the spring arms will effectively be X as indicated in Figure 8. Because this dimension is relatively long, the spring arms provide a relatively low spring rate for closure of the lid and hence it can be closed with relatively little manual force.
From Figure 9 it can be seen that when the lid 4 is closed the spring 24 is bowed in a direction perpendicular to that in which it was bowed by forcing the head 28 between its arms upon closure. This is caused by the pressure exerted on the lid 4 by the seal 83 which is to some extent compressed when the lid is in its closed position. The fulcrums for this mode of bowing are the inner edges of the two bridges 86, which are separated by a distance Y substantially less than distance X. Consequently, the effective spring rate of spring 24 is now greater and it is capable of maintaining a greater compressive force on the seal 83 than if the fulcrums were spaced further apart. This helps to keep the seal 83 compressed firmly against the edges of the wall 84 of the container portion 2 even when the seal may have taken on some permanent deformation.
The bridges 88 are for the purpose of liriting the extent to which the spring 2^J+ can be bowed by the pressure applied to it by the seal 83, so that the spring cannot be permanently deformed.
To form the ribs and bridges shown on the lid in Figures 8 and 9, it is preferably moulded from a suitable plastics material.
The novel and inventive features referred to herein and in the following claims, are each considered to constitute inventions in themselves, and not only when in combination with the other features referred to.

Claims

1. A latch mechanism comprising a first member which is adapted to engage with a second, resiliently displaceable member (22, 24), characterized in that the engaging portions of the members being so formed that a force applied to the members in a direction tending to engage them can cause resilient displacement of the second member to permit engagement of tne latch mechanism, first, manual means for disengaging said members, and additional means for moving one of the members relative to the other when they are in engagement, so as to disengage the members, whereby the members are disengageable both by using said first means or by operation of said moving means.

2. A latch mechanism as claimed in claim 1, wherein said annual means moves the other of the said members relative to said one member, when they are in engagement, so as to disengage the members, and/or wherein the first member (18) includes at least one shoulder (32, 60, 62) and the second member is an elongated spring element (22, 24) behind which said shoulder engages, the shoulder being formed so as to prevent it being disengaged from the spring element by a force opposite to that which causes engagement thereof.

3. A latch mechanism as claimed in claim 1 and/or 2, characterized in that the first member has a head (28) with a said shoulder on each of two diametrically opposed sides thereof, and the shoulders engage with respective spaced-apart spring elements, and/or wherein the two spaced-apart spring elements are tne two arms of an elongated U-shaped spring (24), and/or wherein said first manual means comprises a push-button (64) provided witn one or more cam surfaces which, when the button is pushed, resiliently displace the elongated spring element or elements from engagement with the soulder or shoulders, or wherein said first, manual means is a pivoted control (74) carrying one or more elements which, wnen the control is rotated about its pivot, displace the elongated spring element or elements from engagement with said shoulder or shoulders.

4. A latch mechanism as claimed in any one of claims 1 to 3, wherein the or each elongated spring element (22, 24) is arranged to have a lesser effective spring rate when resiliently displaced during engagement of the latch than it has when force is applied to it by said shoulder in a direction tending to disengage the latch.

5. A latch mechanism as claimed in one or more of claims 1 to 4, wherein each elongated spring element bows resiliently between two spaced-apart fulcrums in response to said first member causing resilient displacement thereof upon engagement of the latch, and bows in a substantially perpendicular direction and between two more closely spaced fulcrums, in response to a force tending to disengage the first member from said spring element, and/or wherein the engaging portions of the members are so formed that a force applied to tne members in a direction tending to disengage them can cause resilient displacement of the second member to permit their disengagement and the first, manual means comprises a finger-engageable portion for enabling manual application of said disengagement force to the members, and/or wherein said one member includes a shoulder, the other member is an elongated spring element over which said shoulder engages when the latch is engaged, and the shoulder is sloped so as to enable it to ride over said spring element when a force is applied to said members in a direction tending to disengage them, and/or wherein said one member has a head with a said shoulder on each of two diametrically opposed sides thereof.

6. A latch mechanism as claimed in one or more of claims 1 to 5, characterized in that each shoulder is formed by one wall of a respective notch, the notches being in opposite sides of said head and the head having a lesser diameter when measured from the trough of one notch to the trougn of the other than when measured across in a direction passing in between the two notches, or wherein each shoulder is formed by one wall of a respective notch, the notches being in opposite sides of said head, the head having a greater diameter when measured from the trough of one notch to the trough of the other than when measured across in a direction passing in between the two notches.

7. A latch mechanism as claimed in any of claims 1 to 6, wherein said other member is the resiliently displaceable member and comprises two spaced-apart spring elements (22, 22) between which the head (28) can be forced to resiliently spread said spring elements until they snap in behind said shoulders, and wherein, preferably, the two spaced-apart spring elements are the two arms of an elongated U-shaped spring.

8. A latch mechanism as claimed in any one of the preceding claims, characterized in that said additional moving means is operable to rotate said one member to disengage it from the other member, wherein preferably said additional said moving means - which preferably comprises an electromagnetic actuator - is adapted to rotate said one member, and the shoulder or shoulders on said one member are arranged to be engageable with the other member when said one member is in one angular position but not when said one member is rotated to another angular position, and wherein, preferably, biassing means are provided for biassing said one member into a position for engagement with the other member.

9. A washing material dispenser for a washing machine, comprising a container portion and an openable lid portion, and a latch mechanism as claimed in any preceding claim for latching the lid portion closed.

10. A latch mechanism, in particular as set forth in one or more of the preceding claims, characterized by a first member (18) biased by means of a spring (50) and actuable by means of a solenoid (44), said first member being provided with notches (30) for cooperating with two arms (22) forming a second member so as to provide a latching function in one position of said first member and a releasing function in a second position of said first member (18).