US3720802A

US3720802A - Switch actuation with lever action

Info

Publication number: US3720802A
Application number: US00260426A
Authority: US
Inventors: H Fischer
Original assignee: Schaltbau GmbH
Current assignee: Schaltbau GmbH
Priority date: 1971-06-08
Filing date: 1972-06-07
Publication date: 1973-03-13
Anticipated expiration: 1990-03-13
Also published as: GB1347596A; FR2140394A1; DE2128322A1; FR2140394B3

Abstract

In a combination of a switch and an operating plunger and of an actuator lever for the plunger, wherein the lever is constructed from a springy strip with a U-shaped recess in one end; the resulting legs of the U are bent back and clamped in-between holder elements on the switch casing from any of four different directions. The other end of the strip is provided for engaging an external actuator for deflection of the strip as a whole with the point of bending of the legs serving as fulcrum. The legs together have width smaller than the width of the strip on the other side of the switch plunger.

Description

United States Patent Fischer l SWITCH ACTUATION WITH LEVER ACTION [75] inventor: Hubert Fischer, Munich, Germany.

[73] Assignee: Schaltbau Gesellschaft mit beschranker Haftung, Munich, Germany [22] Filed: June 7, 1972 [21] Appl. No.: 260,426

[30] Foreign Application Priority Date June 8, 1971 Germany ..P 21 28322.7

[52] U.S. Cl ..200/172 A, 200/153 T [51] Int. Cl. ..H0lh 3/04 [58] Field of Search ..200/172 A, 153 T [56] References Cited UNITED STATES PATENTS 2,454,341 11/1948 Repka ..-.200/172 A X 1March 13, 1973 Wiley ..200/172 A Primary Examiner-H. 0. Jones Attorney-Ralf H. Siegemund [57] ABSTRACT 1n a combination of a switch and an operating plunger and of an actuator lever for the plunger, wherein the lever is constructed from a springy strip with a U- shaped recess in one end; the resulting legs of the U are bent back and clamped in-between holder elements on the switch casing from any of four different directions. The other end of the strip is provided for engaging an external actuator for deflection of the strip as a whole with the point of bending of the legs serving as fulcrum. The legs together have width smaller than the width of the strip on the other side of the switch plunger.

4 Claims, 6 Drawing Figures SWITCH ACTUATION WITH LEVER ACTION BACKGROUND OF THE INVENTION The present invention relates to improvements in switch actuator construction, and more particularly, the invention relates to construction of a lever for transmitting a switch actuation desplacement and force to a reciprocating plunger which operates an electrical switch directly or indirectly (i.e. via other transmission elements); the actuation force and displacement is externally applied. For example, the switch to be actuated may be a limit switch to be responsive to particular position of an object which provides force and displacement for operating the switch.

Actuators for such push button or plunger operated switches include usually lever elements, and various configurations are known here for different purposes and operating conditions. As stated, such switches are frequently used as limit switches which respond to particular positions of displaceable parts in an apparatus, machine or the like. These switches are usually operated by rather stiff levers having a fulcrum point somewhere on the switch box or casing. Some of the known switches have lever actuators which have a springy portion between lever mount and the point of engagement with the plunger or push button. such levers are usually simpler to make as compared with levers that pivot on an axis. Some of these known actuators are connectable in various positions to the switch box so that the actuator lever can be mounted in correspondence to the direction of external actuation. In some cases provision must be made for the lever to continue its displacement over some length after switch action has already taken place. This requirement complicates matters as it necessitates providing of resilient intermediate members such as spring biased intermediate plungers, to be mounted on the lever for slidable displacement etc.

DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a lever type actuator for such a push button or plunger operated switch which is readily placeable as to its relative position, particularly as far as adaptation of the switch to the location of the external actuator is concerned. Moreover, the lever should permit over-shoot-- ing of operational displacement in a manner which does not require special adaptation. The switch itself should not require specific features for adaptation to specific external operating conditions such as configuration of parts and objects operating the switch and providing displacement and force for this purpose. Rather, various external operating conditions should be accommodated through simple constructural variations of the lever, however, without modification of its basic operational principles.

In accordance with the preferred embodiment of the invention, it is suggested to construct the actuator lever from springy strip having a U-shaped slot on one end which extends sufficiently deep into the strip so that (a) the bottom of the U is (or can be placed) rather close to the point of engagement with the plunger or button of the switch to be actuated; (b) portions of the leg of the U are bent back and engage laterally resiliently holders on the switch casing such as protruding bolts, noses or the like. The other end of the strip is provided to offer its surface or a portion thereof in suitably adapted configuration to the externally applied force for switch actuation.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed that the invention, the objects and features of the invention and further objects, features and advantages 7 thereof will be better understood from the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of disassembled components for practicing the preferred embodiment of the invention;

FIG. 2 illustrates, also in perspective view, the components of FIG. 1, but in assembled configuration; and

FIGS. 3 through 6 are edge views of various configurations for the switch actuating lever usable within the configuration of FIGS. 1 and 2.

DESCRIPTION OF THE DRAWINGS Proceeding now to the detailed description of the drawings, FIGS. 1 and 2 illustrate the switch actuator mechanism in different states of assembly. A switch box or casing 1 has a relatively large surface carrying a cover plate 2 which in turn has a central opening. A plunger 3 projects through the opening of plate 2. The switch proper is contained in casing 1, and plunger 3 provides for immediate switching action in the box. The particular relevant features pertain to the operation and actuation of plunger or button 3.

Four bolts 4 are threaded into plate 2, so that their heads do not engage plate 2 and portions of the shanks project above the top surface of the plate. The actuating lever 5 of interest consists essentially of a strip of elastic, springy material (e.g. steel). One free end 12 of this strip is provided for exposure to an external element, part or object which provides switching actuating force and displacement (arrow A), so that the actuator lever 5 may transmit that force to the plunger 3.

The other end of actuator lever 5 has a U-shaped recess 6 with a bottom 7 which is located close to the point of engagement of actuator strip 5 and plunger 3 when the actuator is mounted to the switch (FIG. 2). The two legs 8 of the U are bent back by about As actuator 5 is inserted, the bent back portions of legs are squeezed together in the plane of the U so that these leg portions can be shifted under the heads of bolts 4. Indentations 9 in legs 8 receive the bolt shanks directly underneath the heads in resilient abutment.

It can be seen that the utilization of bolts 4 for the stated purpose is just a matter of convenience. The plate 2 could have legs with cut grooves. Other protruding parts and noses integral with the plate could be provided for purposes of providing for the same retaining function of lever 5 on plate 2 through resilient engagement with legs 8.

It should be noted that the bolts 4 are provided as corner points of a square; plate 2 may also be squareshaped which is incidental. However, it is important that the aperture in plate 2 and the location of plunger 3 is located in the center of the square as defined by bolts 4. Thus, the actuator lever 5 can be shifted into position from four directions as indicated by the arrows B in FIG. 1.

The construction illustrated in FIGS. 1 and 2 can be modified within the scope of this invention. For example, bolts 4 could be provided on another side of box 3, e.g., on side 10. The legs 8 need to be bent only by 90 for this case.

Another modification is depicted in FIG. 3, showing the free lever arm of the actuator element to be enlarged (12'), thereby extending the lever arm as effective for receiving the externally applied force which can be smaller accordingly.

As shown in FIG. 4, the actuator arm proper may carry an element 14 for mounting a pully, cam roll 15 or the like, in case the external actuator undergoes motion that has components not only in transverse orientation to the actuator but also of longitudinal orientation.

As shown in FIG. 5, the free end of the actuator lever may have a crimped portion 16 which is beneficial in case the external force is applied through a broader surface.

The construction shown in FIG. 6 has also the actuator arm bent back (17) which is beneficial in case the external force acts in line or in approximate alignment with plunger or button 3 as indicated by the extended center line for plunger 3.

It can readily be seen that the modifications of FIGS. 3 to 6 can be combined in that, for example, the long arm of FIG. 3 or the bent back arm of FIG. 6 is crimped as per FIG. 5 or provided with a cam roll as per FIG. 4.

Turning now to some specific features which the various examples have in common, it is pointed out that for similar thickness of the strip 5, the width of the springy portions can be suitably proportioned so that upon actuation of lever arm 12 only the relatively narrow portions 11 of legs 8 are resiliently deformed. In other words, deformation is to occur only, or only to any substantial degree, in that part of actuator strip 5 that extends between the mounting points of legs 8 at the rearmost two bolts 4 and the point of engagement of strip 5 with button 3. The lever arm (12) portion as extending between the point or region of engagement with plunger 3 and the free end of the actuator strip is to be sufficiently broad, so that this portion acts like a stiff lever.

If the lever strip has the same width at both sides of the point of engagement with plunger 3, then the free arm end could bend more strongly, possibly with plunger 3 establishing a secondary fulcrum. That, in turn, would extend the displacement path for the external actuation prior to achieving switching action; thus, the resilient reaction of the different strip portions would be introduced as parameter in the determination of the length of that displacement path. Such a parameter is undesirable as inherent variations of resilient reaction of the strip between button 3 and its free end varies the displacement path length under similar external operation conditions. If, however, the free arm reacts essentially as a stiff lever, the displacement path length is rendered independent from resilient reactivity of the stringy strip.

The bent portion 18 in FIG. 6 is to be wider than the width of arms 8 at 11 taken together, so that there is little resilient flexing at 18.

The considerations concerning the width of strip 5 in different portions are not invalidated b; the somewhat tapered end of arm 12 (FIGS. 1 and The fulcrum point near bends 11, is the location of principle resilient reaction; the region of strip 5 immediately in front of (toward arm 12) the point of engagement with plunger 3 is most susceptible to the setting up of another fulcrum point and resilient bending. However, it is the width of that portion or strip which is to be larger than the width of the two arms 8 together and here particularly of portions 11, so that actual resilient flexing occurs only in the latter not in the former.

Thus, the invention provides indeed for rather uniform displacement path length for switch actuation even if the individual elements have wide tolerances.

The invention is not limited to the embodiments described above but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be included.

I claim:

1. In a combination a switch and casing, an operating plunger and an actuator lever for the plunger, the improvement comprising:

the lever constructed from a springy strip having first and second ends; a U-shaped recess. in the strip at the first end, resulting legs of the U shaped recess being bent back, each having two oppositely oriented edges;

holder elements on the switch casing disposed for engaging the bent-back legs at the oppositely oriented edges upon resilient deformation of the bent back legs in the plane of the strip and in opposing directions therein, corresponding to the mutual edge orientation, clampingly receiving the bent back legs so that the plunger may engage the strip near the bottom of the U shaped recess;

the second end of the strip provided for receiving an external actuator for deflection of the second end with component of displacement transverse to the plane of the strip, the width of the strip on the side of the second end adjacent the point of engagement with the plunger being wider than the sum total of the width of the bent back legs.

2. In a combination as in claim 1, there being an additional projecting element mounted on the second end of the strip.

3. In the combination as in claim 1, the strip being crimped near the second end.

4. In the combination as in claim 1, the strip being bent back to provide for a surface portion for application of switch actuating forces in alignment with the plunger.

Claims

1. In a combination a switch and casing, an operating plunger and an actuator lever for the plunger, the improvement comprising: the lever constructed from a springy strip having first and second ends; a U-shaped recess in the strip at the first end, resulting legs of the U shaped recess being bent back, each having two oppositely oriented edges; holder elements on the switch casing disposed for engaging the bent-back legs at the oppositely oriented edges upon resilient deformation of the bent back legs in the plane of the strip and in opposing directions therein, corresponding to the mutual edge orientation, clampingly receiving the bent back legs so that the plunger may engage the strip near the bottom of the U shaped recess; the second end of the strip provided for receiving an external actuator for deflection of the second end with component of displacement transverse to the plane of the strip, the width of the strip on the side of the second end adjacent the point of engagement with the plunger being wider than the sum total of the width of the bent back legs.