GB2153898A - Latch mechanism - Google Patents

Abstract

This invention is a handle (19) and wand (11) latching arrangement for use remotely from a suction cleaner having a hose connected between the handle and the cleaner body. The wand (11) can be engaged in a socket (12) in the handle (19) by means of a stud (13) on the wand in a slot (14) in the socket against an abutment (16) in combination with a latch (27) pivotally and slidably mounted at (29) in relation to the handle so that in the locked position surfaces on the latch engage both the stud (13) and the abutment (16) and release cannot be effected by pivotal movement of the latch alone. Release movement of a button (33) first causes trunnions (29) to slide rearwardly along grooves (32) until a surface (43) on the catch is spaced from a surface (42) on the abutment (16) so that further movement produced by pushing the button (33) allows the catch (34) to pivot free of the stud (13). <IMAGE>

Description

SPECIFICATION Latch mechanism This invention relates to latch mechanisms, and is particularly but not exclusively, concerned with a latch mechanism which is employed for the simple securement and release of relatively slidable parts, for example a suction cleaning tube or so-called wand, and another part of the cleaner.

It has been common practice for many years for suction cleaners to employ suction hoses and/or lengths of rigid suction tubing, known as wands, in order to enable the user to operate the suction cleaner through a separate suction nozzle positioned away from the main body of the cleaner. In some instances, this is done by so-called "conversion" of an upright suction cleaner, which normally is used for cleaning carpets via a suction nozzle in the cleaner body itself. In this instance, by use of suitable conversion mechanism, the suction flow is diverted from the main suction nozzle to a tube, hose or the like attached to the cleaner.The tube or hose carries at its end a suction cleaning tool for example, a brush, by which the cleaner can be employed either for "off-the-floor" cleaning wherein the tool is used for cleaning walls, curtains, furniture or the like, or for the cleaning of carpets in less accessible positions, for example under furniture or close to skirting boards.

Other types of cleaner, generally known as canister cleaners, do not have an integral suction nozzle and therefore all the suction cleaning operations are carried out via suction hose and/or tubes extending to suction nozzles or the like.

There have been recent developments whereby the suction hose or tube terminates in a suction nozzle within which a rotary agitator is mounted to be driven by a motor carried by the nozzle itself, and powered by a source of electricity carried to the nozzle via a cable extending either down the tube itself or attached to the tube at certain places.

With all these arrangements it is necessary for the suction hose or tube readily to be attached and detached from the body of the suction cleaner whether it be of an upright or canister nature. It is also necessary for sections of such tube or hose to be connected one to the other and in some instances for a main handle of the suction tube or hose to have connected to it further sections of tube or hose in a readily detachable manner.

These systems all demand the use of a suitable manually operated latch. An example of such a latch is shown in Fromknecht's U.S.

Specification 3245698 in which two tubular members are inter-connected by a latch member which carries a hook-shaped latch portion for engagement over a projection carried by one of the tubes. This form of latch is a simple hook which is moved into or out of engagement with the projection respectively by a camming operation for engagement, and by a pressing operation for release.

This specification is one example of many prior arrangements of this type but despite the efficiency of this type of latch over the years, particularly with those which the Applicants have embodied in many hundreds of thousands of suction cleaners, it is believed that improvements can be made, particularly to ensure a positive retention where a heavy nozzle on the end of the hose or tube is liable to application of shock either of a compressive or tensile nature along the length of the tube, so imposing a compression or tensile load on the latch. With a simple hook-latch which engages over a projection on the tube, if the tube and projection are all moulded in plastics material, there is a danger of the projection being distorted or seriously damaged by tensile loads which tend to cause the hook to cut into the projection.Equally, compressive loads along the length of the tube can tend to cause damage to the latching mechanism.

It is accordingly a principle object of the present invention to overcome or alleviate these disadvantages and to provide a form of latch mechanism of general application but particular application to suction cleaners where secure latching of the parts one to another can be achieved.

According to the present invention a latch mechanism for releasably securing relative slidable components includes co-operating stops on the respective components and a catch mounted on one component for engaging behind the stop on the other component to hold them together.

The invention can be further characterised by any one of, or any combination of any of, the following features.

The catch may be associated with a spaced engagement surface enabling the two stops to be embraced between the catch and the engagement surface. For example the engagement surface may be integral with the catch.

The space engagement surface and the surface of the stop on the other component with which it co-operates, may be inclined in such a way as to prevent release of the catch merely by pivoting of the catch; the same effect may be capable of achievement by having only one of the surfaces so inclined.

The catch may be mounted on the one component through means allowing both relative sliding and relative pivoting of the catch in relation to the component; thus after some initial sliding it may be possible to release the catch merely by pivoting of the catch.

There may be spring means--conveniently integrally moulded with the rest of the catch-for biasing the catch against sliding movement in relation to the one component, and possibly also, or alternatively, biasing the catch against pivoting release movement of the catch.

The catch can be assembled with the one component merely by being snapped into a compartment formed in the one component without requiring permanent fastening. In the assembled position the springs can conveniently be strained.

The one component is conveniently a handle of a suction cleaner or other imple ment, and then the other component may constitute a wand for leading to an operating nozzle.

When used with a suction cleaner or other electrical equipment, such a handle can be provided with switches for such purposes as operating the cleaner, and/or operating a tool coupled to the cleaner through the wand.

The invention may be carried into practice in various ways, and one embodiment will be described by way of example only, with reference to the accompanying drawings, in which: FIGURE 1 is a perspective view of the end of a wand latched into a wand handle; FIGURE 2 is an exploded view generally corresponding with FIGURE 1, showing components of the latch mechanism; FIGURES 3 and 4 are respectively a side elevation and an underneath view of a latch; and FIGURES 5-10 are sectional elevations of parts of the mechanism showing the latch respectively latched,in an intermediate position, and released, in FIGURES 5,6, and 7, with the components immediately adjacent the latch shown in similar sections to an increased scale in FIGURES 8. 9 and 10.

The positions of the section lines in FIG URES 5-10 as related to FIGURE 4 will become apparent as the description proceeds.

The wand 11 is a plastic moulding arranged to be a slide fit in a cylindrical socket 12 in the handle. The wand is moulded with a projecting radial stud 13, which can enter a slot 14 in the cylinder wall defining the socket 1 2. and between two shoulders 15 of an abutment 16 against which the stud rests and is located in a shallow arcuate recess 17. The stud 13 has a fiat face 18 facing away from the recess 17.

The handle shown generally at 19 in FIG URE 1 has three principle components namely a base 21 in which the cylinder socket 12 is moulded, an upper part 22 which is not shown in FIGURE 2. and a cover 23 which is only shown in FIGURE 1, although its front edge can be seen in FIGURES 5.6, and 7.

The base 21 is formed with a pair of laterally spaced upstanding walls 24 and a boss 25 having a threaded hole by means of which the upper part 22 can be secured to the base through a screw 26. Further bosses and screws for making a secure connection cannot be seen in the figures.

The other principle component of the handle is a latch 27 moulded from polypropylene or some other resilient plastics material with good fatigue strength.

The latch can be seen from FIGURES 3 and 4 to have a central latching portion 28 with which are moulded transverse trunnions 29 having at their outer ends elongate leaf springs 31. The trunnions 29 can slide and rock in respective grooves 32 formed one in the top of each wall 24. The latch is also formed integrally with an operating button 33 and a catch 34 for engagement against the face 18 of the stud 13.

The catch 34 has a shoulder 35 for enagement with the face 18 of the catch 13 in the latched position, and a ramp 36 leading to the shoulder so that as the wand is inserted in the socket 12 the leading edge of the stud 13 acts on the ramp 36 to deflect the catch away from the socket and allow the stud to pass underneath it after which the resilience of the material of the latch 27 ensures that the catch engages behind the stud 13 as shown in FIGURES 5 and 8.

The latch is assembled in a compartment 37 formed in the upper part 22 of the handle, as can be seen best in FIGURE 10. The button 33 protrudes through a slot 38 in the front face of the upper part and the catch is seated in a lower slot 39 below the slot 38 and being open ended at its lower edge so that the ramp 36 on the catch 34 is exposed to co-operative action with the stud 13. The leaf springs 31 are strained to rest against a wall 41 which is an integral part of the upper part 22 and forms a rear wall of the compartment 37.

In that assembly, when the upper part is fitted on the base 21 of the handle, the trunnions engage in the grooves 32 at the top of the walls 24 and that arrangement can be seen best in FIGURES 8,9 and 10 showing respectively the conditions when the wand is latched in position in the handle, when the catch is in an intermediate position , and when the catch is deflected and the wand is released.

It is convenient to explain here that in FIGURES 5.6, and 7 the section line is a median line as indicated at X-X in FIGURE 4.

In FIGURE 8. the section line is the same except at a local part around the trunnion 29 where the section is taken on the line Y-Y in FIGURE 4, so that the wall 24 can be seen in elevation and the trunnion 29 in section. In FIGURE 9. the local section is taken on the line Z-Z in FIGURE 4, so that the leaf spring 31, the trunnion 29, and the wall 24 behind them are seen in elevation. In FIGURE 10 the section line is the median line X-X as in FIGURES 5,6, and 7.

The drawings have been prepared in that way so that the action of the catch 34 can be clearly seen, both as regards movement of the trunnions 29 in their grooves 32, and as regards engagement of the catch 34 with the stud 13.

In connection with the latter point, it has to be noted that the abutment 16 formed on the base 21 has a face facing the stud 13 which is generally perpendicular to the axis of the cylindrical socket 12 but it has a rear face 42, (FIGURES 8,9 and 10) which is inclined rearwardly so that the thickness of the abutment 16 is a little greater further from the axis of the socket than where it joins the wall of the socket. The catch is formed with a co-operating face 43.

The operation of the latch will now be described.

In the latched conditions, shown at FIGURE 8, it is virtually impossible to release the wand from the socket inadvertently without pressing the button 33, because any twisting or pulling movement of the wand which might tend to produce a release force on the shoulder 35 on the catch 34 is resisted by the action of the co-operating face 43 of the catch on the rear face 42 of the abutment 16 on the base 21, and the face 43 cannot slide up the face 42 because of the rearward inclination described above. Forward movement of the latch in relation to the base is also resisted by engagement of the trunnions 29 in the front faces of the grooves 32 and the leaf springs 31 ensure that in the absence of pressure on the button 33 the trunnions 29 do bear against the front faces of the grooves.

The stud 13 and the abutment 16 are positively held snugly together between the faces 35 and 43 on the catch.

When it is desired to release the wand and the operator presses the button 33, the latch 27 cannot immediately pivot about the trunnions 29 because of the reaction of the face 42 against the face 43, and so the initial movement produced by pressing the button 33 is as shown in FIGURE 9 where the latch is in an intermediate position with the trunnions 29 sliding rearwardly along the grooves 32 and straining the springs 31. That initial movement allows the face 43 to move rearwardly clear of the face 42 on the abutment 1 6 initially by pivoting the whole of the latch about the point of contact of the catch 34 with the stud 13. Once the face 43 has moved clear of the face 42, further movement of the latch can be by pivoting about the trunnions 29.When the trunnions reach the rear of the grooves 32, as shown in FIGURE 10, the catch 34 has lifted sufficiently to allow the stud 13 to be released with the wand 11, and it is to be noted from FIGURE 10 that in that position the faces 42 and 43 are still in engagement although now the point of engagement is near the outer end of the abutment 16. When the button 33 is released the resilience of the springs 31 moves the trunnions back to the front of the groove and the latch returns to the position shown in FIGURE 8, although now the wand has been released.

On re-engagement it is not necessary to press the button because the stud 13 strikes the ramp 36 on the catch 34 and although it cannot immediately lift the catch, it can push the latch rearwardly as the trunnions 29 slide along the slots so that immediately afterwards, further movement of the stud into the socket can lift the catch as pivoting occurs about the trunnions. Once the stud has passed under the lifted catch to abut against the abutment 16, the springs 31 cause the trunnions to slide back to the other end of the grooves and allow the catch to re-engage as shown in FIGURE 8.

The mechanism is easily assembled from components which are plastics mouldings, so that once the tooling has been completed, manufacture and assembly are cheap and simple, but yet an efficient latch mechanism is provided which is reasonably proof against inadvertent release of the wand without the operation of the button 33.

FIGURE 1 shows that the handle 19 is formed with various switches, as indicated at 44, which may be used for such operations as connecting a power supply from a suction cleaner canister or body through the handle to a lead running down the wand 11 to a motor driven device in a nozzle at the end of the wand. Such a device might be a beater or a motor driven brush.

The handle itself can be connected to the body of the cleaner through any suitable connection and a long flexible pipe putting the body of the cleaner into contact with the body of the housing will enable the wand and the nozzle at the end of it to be easily used at a considerable distance from the body of the cleaner and its power supply.

The type of handle shown with the release mechanism described, and the electrical switches enables the user to clean efficiently in places that might otherwise be inaccessable using a variety of tools any of which can be very easily engaged with the handle itself, and released from it.

FIGURE 1 in conjunction with FIGURE 8 shows that in the latched position it is clearly more difficult to release the latch by lifting under the end of the catch 34 than by pushing the button 33, so that release of the latch due to inadvertent operation of the catch 34 is most unlikely.

Claims (14)

1. A latch mechanism for releasably securing relative slidable components including cooperating stops on the respective components and a catch mounted on one component for engagement behind the stop on the other component to hold them together, the catch being associated with a spaced engagement surface enabling the two stops to be embraced between the catch and the engagement surface.

2. A mechanism as claimed in Claim 1 in which one or both of the engagement surface and the surface of the stop on the other component with which it engages are inclined in a sense to prevent release of the catch merely by pivoting of the catch.

3. A mechanism as claimed in either of the preceding claims in which the spaced engagement surface is integral with the catch.

4. A mechanism as claimed in any of the preceding claims in which the catch is mounted on the one component through a connection permitting both relative sliding and relative pivoting of the catch in relation to the one component.

5. A mechanism as claimed in Claim 4 in which to release the catch the catch can be first slid in relation to the one component and can then be pivoted for release of the catch.

6. A mechanism as claimed in claim 4 or Claim 5 including spring means biasing the catch against sliding from the position in which the catch cannot pivoted in relation to the one component.

7. A mechanism as claimed in claim 6 in which the spring biases the catch against pivoting in a sense to release the catch.

8. A mechanism as claimed in Claim 6 or Claim 7 in which the spring is integral with the catch.

9. Mechanism as claimed in any of the preceding claims in which the catch is retained assembled with the one component by being snapped into a compartment in that component without being permanently secured to it.

10. A mechanism as claimed in any of the preceding claims in which one or all of the components of the catch are plastics mouldings.

11. A latch mechanism for releasably securing relative slidable components constructed and arranged substantially as herein specifically described with reference to FIGURES 210 of the accompanying drawings.

12. A mechanism as claimed in any of the preceding claims in which the one component is a handle for carryingand/or manipulating the other component.

13. A latch mechanism as claimed in Claim 12 in which the handle is a remote control handle for a suction cleaner tool for connection to a wand constituting the said other component.

14. A mechanism as claimed in Claim 13 in which the remote control handle includes controls for operating a remote suction cleaner and/or for operating a tool communicating with the handle through the wand and/or for controlling a lamp to be carried by the wand.