GB2187250A - Lever arm for locking mechanism - Google Patents

Abstract

The lever is intended for locking mechanisms, in particular, for manually operable toggle locking mechanisms, wherein the levers, viz. the clamping and actuating arms, are formed of two mirror-inverted identical flaps (1,4) and the said flaps, at the ends (1', 4') in abutting relationship, are rigidly interconnected. To avoid that the flaps are - as in the past - welded together thereby precluding an interruption of the flow of manufacture of levers of this type, the lever is of a configuration such that, in at least one flap (1,4), in the area of its abutting parts (1', 4'), at least one punch hole (2) is provided to be engaged by a stationary engaging element stationarily located on the respectively other flap (4,1). <IMAGE>

Description

SPECIFICATION Lever arm for locking mechanism The present invention is concerned with a lever arm for locking mechanisms, in particular, hand-operated toggle locking mechanisms, wherein the levers, viz. locking and actuating arms, are each formed of two identical mirrorinverted flaps and the said flaps, at the ends in abutting relationship, are rigidly interconnected.

Locking mechanisms, in particular, hand-operated toggle locking mechanisms of the afore-described type, are known in the art, wherein the locking and actuating arms are of identical mirror-inverted configuration and, in joined condition, form the levers for the locking mechanism, which, pivotally and hingedly combined, are disposed in an apparatus housing equally made up of suitably deformed and cut-to-size punching elments. The connection between the two flaps, hitherto, has been by spot welding seriously affecting and interrupting the flow of manufacture as the parts, after welding, will first have to cool down to be subsequently galvanized in welded-together condition. This will be necessary for reasons of corrosion resistance and for hiding the colour changes caused by spot welding.As mechanisms of this type and individual parts thereof, respectively, are being manufactured in large piece numbers, the connecting method hitherto employed involving a cooling need, serious hampers the manufacturing process.

It is the object of the present invention to overcome this disadvantage, i.e. improve the lever of the aforedescribed type concerning the connection of the two flaps thereof thereby eliminating special cooling.

This problem is solved by a lever of the afore-mentioned type, in the practice of the invention, in that disposed at least in one flap, in the area of the abutting portions thereof, is a punch hole to be engaged by a stationary engaging element stationarily disposed on the respectively other flap. According to advantageous and practical forms of embodiment, the engaging element on the other flap is in the form of a recess pressed into the punch of the other flap, with the recess, advantageously, being provided with a peripheral knurling. As this form of embodiment is the easiest one to realize, it is the preferred one.

According to another form of embodiment which, however, involves slightly enhanced efforts, in each of the two flaps, at least one punch in registry with the other is provided while a connecting pin the length of which corresponds to the twofold wall length of a flap, is forced into both holes. Also, in that embodiment, the connecting pin, preferably, is provided with a knurling.

Apart from the required provision of a connecting pin with the second alternative, both solutions substantially reduce the efforts involved with the manufacture and assembly of levers of this type as processing can be directly continued after joining of the two flaps.

As the flaps forming the levers are anyway punched and press-moulded in corresponding tools it is easy to incorporate the said formation of the required holes and press mouldings along with peripheral knurlings into the punching and moulding operations. Even if separate manufacturing processes were required this would be acceptable as they would still involve a substantially more favorable relationship as compared with conventional methods of manufacturing levers of this type. Rigidly connecting two sheet metal parts in purely mechanical manner and providing a suitably punched or stamped deformation on both parts may, admittedly, be known. However, it is amazing that, hitherto, such a purely mechanical connection for levers of this type has never been taken into consideration and that spot welding has rather always been used instead.A reason for this may have been that levers of this type are located in the housing in ciose relationship in a manner to be just pivotable about their joints. Another reason for not employing purely mechanical stamping connections may have been that, normally, they result at least on one side in projections protruding from the corresponding surface of the item and must, if possible, be removed again to permit a correspondingly close location of so connected parts, as mentioned, between guiding elements. It is thus of importance to the suggested new solutions that punched holes be provided and, in the former instance, the knurled recess of the one flap only engage the hole of the other flap rather than protrude from the other side of the hole.

The same applies to the peripherally knurled connecting pin the maximum length of which corresponds to the twofold strength of a flap.

As the levers and the flaps forming the levers, respectively, in the hinged zones are anyway guided with respect to one another, actually, it would be sufficient to provide a point of connection externally of the hinged zone to lock the two flaps against twisting. In that respect it would, optionally, be adequate either to drive the recessed stamps not provided with knurlings sufficiently deeply into the hole of the neighboring flap, or, if holes are provided in each of the flaps, to drive a corresponding un-knurled locking pin tube thereinto. However, the knurled configuration of the recesses and connecting pins, respectively, is the preferred one as this type of connection has proved to be most resistant, at the same time establishing a reliably rigid connection disconnectable only by force.An equivalent. purely mechanical connecting effect could also be provided by abandoning the configuration of the flaps consistently-mirror-invertedly-identical in all areas and providing the one flap in the punching blank with small foldable extensions for which corresponding recesses would have to be provided on the other flap to fold thereinto the extensions in form-locking manner. Despite a comparable connecting effect, this would, however-as is readily apparent-result in enhanced manufacturing efforts as the preferred mirror-invertedly identical configuration of the flaps would have to be abandoned.

The lever according to the invention will now be described in greater detail with reference to the graphical illustration of examples of embodiment.

In the drawings, Fig. 1 schematically shows a side view of an actuating lever for a locking mechanism of the type under consideration, shown only by way of example in Fig. 8; Figs. 2+3 are plan views of the flaps respectively of mirror-inverted identical configuration and forming the lever according to Fig.

1; Fig. 4 is a plan view of the two flaps according to Figs. 2 and 3 in joined-together condition; Figs. 5+6 are plan views of the flaps to be joined to form a clamping arm according to Fig. 7; Fig. 7 is a side view of the force arm comprising the flaps according to Figs. 5,6; Fig. 8 is a side view of a toggle lock mechanism of the type under consideration, and Fig. 9 is a perspective view of two flaps interconnected otherwise.

As disclosed by Fig. 8, locking mechanisms of this type comprise a so-called clamping arm 7 and an actuating arm 6 pivotally interconnected by an intermediate element 8 and, in turn, arranged to swivel on housing 9 of the locking mechanism including joints 10,11.

Especially for locking mechanisms that are manually operable, the clamping arm 7 and the actuating arm 6 according to Figs. 2,3 and 5 6 are formed of easily punched and pressmoulded flaps which are of mirror-inverted identical configuration and are joined together to be hinged to the housing in engaging or externally straddling relationship, as shown in Fig. 4 (which also applies to the flaps according to Figs. 5,6). As the articulated attachment to the housing precludes a non-pivoting connection from being established between the flaps, they will have to maintain a rigid connection with respect to one another which, as mentioned earlier, hitherto has been performed by manufacture-delaying welding processes.When maintaining the mirror-inverted identical configuration of flaps 1,4 according to Figs. 2,3 and 5,6, flap 1 is provided with one or two fully punched-through holes 2, whereas the respectively other flap 4, in the area in registry therewith, is provided with a recess 3 the outer periphery of which, advantageously, is of a knurled configuration. This is simply achievable in that the flap concerned is stamped against a matrix comprising a correspondingly knurled depression and, in diameter, being so dimensioned that the outer diameter of recess 3 is slightly larger than the diameter of the hole 2. When joining together the flaps 1,4 as shown in Fig. 4, all recesses 3 are impressed, by press force, into the passage holes 2, which involves a corresponding deformation of the knurling tips and partial cutting thereof into the respective hole wall.

This will safely fix the flaps with respect to one another and enable them to be hinged on housing 9 to the appertaining joint 10 or 11.

As shown in Fig. 4, the non-pivoting connection between the two flaps 1,4 can also be achieved in that passage holes 2 are punched into both flaps in registry with one another and that a circumferentially knurled connecting pin 5 is driven into the said holes. In the construction as shown in Fig. 8, it is of importance to the clamping arm that no protruding parts of recesses 3 and the connecting pins 5, respectively, are formed as the clamping arm with the part engaging the housing 9 must be able to unimpedely move therein.

This will also be of importance to the actuating lever 6 inasmuch as handles of this type, in the majority of cases, will be coated with a plastic handle sleeve; protruding parts, if any, would thus preclude such sleeve from being smoothly pushed on. If other or additional articulated members are added to such locking mechanisms, that, equally are simply formed of double flaps, the same connecting principle will, of course, be applicable to the rigid connection thereof.

In the form of embodiment according to Fig.

9, flaps 1,4, basically, are also of a mirrorinverted identical configuration, with the exception of a minor difference to the effect that flaps 1,4pin the peripheral area are provided with a groove 12 and, on the opposite side, with a small flag 13 so that the flag 13 of each flap 1,4 can be folded into the groove 12 of the respectively other flap and firmly pressed into the groove.

Claims (10)

1. A lever arm for locking mechanisms, in particular, for hand-operated toggle locking mechanisms, wherein the levers, viz. locking and actuating arms, are each formed of two mirror-inverted identical flaps, and the said flaps, at the ends in abutting relationship, are rigidly interconnected, characterized in that provided in at least one flap (1,4) in the area of abutting parts (1', 4') is at least one punch hole (2) engaged by a stationary engaging element stationarily located on the respectively other flap (4,1).

2. A lever arm according to claim 1, characterized in that the engaging element on the flap (1,4) is in the form of a recess (3) pressed into the hole (2) of the other flap.

3. A lever according to claim 2, characterized in that the recess (3), at the outer periphery,is provided with a knurling.

4. A lever according to claim 1, characterized in that provided in each of the two flaps (1, 4) is at least one punch hole (2) in registry with the other hole, and pressed into the two holes (2) is a connecting pin (5) the maximum length of which corresponds to the double strength of a flap (1,4).

5. A lever arm according to claim 4, characterized in that the connecting pin (5), on the external periphery thereof, is provided with a knurling.

6. A lever arm according to claim 1, characterized in that the punch hole of the one flap (1) is in the form of a groove (12) located marginally of the flap, while the engaging element of the other flap (4) is in the form of a flag (13) folded and pressed into the groove (12).

7. A lever arm according to claim 6, characterized in that provided in each flap (1,4), at respectively opposite edges,arexat least one groove (12) each and one flag (13) each.

8. A lever arm substantially as hereinbefore described with reference to Figs. 1 to 4 and 8 of the accompanying drawings.

9. A lever arm substantially as hereinbefore described with reference to Figs. 5 to 7 of the accompanying drawings.

10. A lever arm substantially as hereinbefore described with reference to Fig. 9 of the accompanying drawings.