JPH0377610B2 - - Google Patents

Description

Claim 1: A mechanical operating mechanism for an optical key switch that switches the switch by opening and closing a path of light emitted from a light source, comprising: a fixed member having a fixed side optical path; and a moving side light. a movable plunger having a passage and slidably held by the fixed member, the moving side optical passage and the fixed side optical passage being aligned during the movement of the movable plunger, disposed between the fixed member and the movable plunger, a first free end and a second free end;
a torsion spring having an intermediate portion including a coil portion; a torsion spring support point provided on one of the fixed member or the movable plunger for supporting the torsion spring coil portion; and spaced apart from each other; first and second contact points provided on the other of the fixed member or the movable plunger so as to contact the first and second free ends, respectively, and as the movable plunger slides. , the torsion spring support point is provided in a positional relationship such that it moves relatively from one side to the other side of a line connecting the first and second contact points, whereby the torsion spring supports the As the movable plunger slides, the first and second free ends change from a shape forming an inferior angle to a shape forming a dominant angle, and the distance between the first and second contact points is , the torsion spring is selected to be always smaller than the spacing between the first and second free ends, regardless of changes in the shape of the torsion spring, and the torsion spring resists the operating force for moving the movable plunger. The restoring force of the movable plunger reaches a maximum value during the movement of the movable plunger, and the moving side optical path and the fixed side optical path are connected at a position of the movable plunger where the restoring force of the torsion spring approaches the maximum value. are arranged so that
Mechanical operating mechanism.

2. The machine according to claim 1, wherein the torsion spring support point is provided on a rod-shaped member that attracts the coil portion, and the coil portion is unwound as the movable plunger slides. operation mechanism.

3. According to claim 1, the torsion spring support point is provided on a rod-shaped member that attracts the coil portion, and the coil portion is wound more tightly as the movable plunger slides. mechanical operating mechanism.

1 Field of the Invention The present invention relates to an operating mechanism for and as used in keyswitches used, for example, in reconfigurable keyboards. More particularly, this invention relates to a key switch for a reconfigurable photo-optical keyboard having a novel operating mechanism using torsion springs.

2 Description of prior art Keyboard switches of prior art generally include:
A coil spring is used, one end of which (generally the lower end of the spring) is secured to the base support member, while the other end is secured to the movable member of the key switch. The construction requires top and bottom attachments, as well as some means of retaining the key axle from falling out of the bottom of the base structure assembly. Usually this structure is the bottom or baseboard of the keyboard. This type of key and key and keyboard configuration replacement, reconfiguration, or servicing requires special tools and is time consuming and inefficient. Also, the prior art keyswitches are generally relatively complex in construction and require relatively many operations to manufacture and insert into the keyboard, often requiring significant manual labor.

Other keyboard systems of the prior art result in very undesirable abrasion.

Magnetic type keyswitches tend to provide operators with large variations in force and effectiveness from key to key. This lack of evenly increasing tactile sensation is highly undesirable since the operator is unable to detect that the key switch has actually been closed.

SUMMARY OF THE INVENTION A mechanical operating mechanism according to the invention is for an optical key switch that switches by opening and closing a path of light emitted from a light source. The mechanical operating mechanism includes a fixed member, a movable plunger, a torsion spring, a torsion spring support point, and first and second contact points. The fixed member has a fixed side optical path. The movable plunger has a moving optical path and is slidably held by the fixed member. The movable optical path and the fixed optical path are aligned during the movement of the movable plastic gear. A torsion spring is disposed between the stationary member and the movable plunger and has a first free end, a second free end, and an intermediate portion including a coil portion. A torsion spring support point is provided on one of the fixed member or the movable plunger for supporting the coil portion of the torsion spring. The first and second contact points are spaced apart from each other and are provided on the other of the fixed member or the movable plunger to contact the first and second free ends, respectively. As the movable plunger slides, the torsion spring support point is provided in a positional relationship such that it moves relatively from one side to the other side of a line connecting the first and second contact points. Thereby, the torsion spring changes from a shape in which the first and second free ends form an inferior angle to a shape in which the first and second free ends form a dominant angle as the movable plunger slides. Here, the inferior angle refers to an angle larger than 0 degrees and smaller than 180 degrees. A dominant angle is an angle greater than 180 degrees and less than 360 degrees. The spacing between the first and second contact points is chosen to be always smaller than the spacing between the first and second free ends, regardless of changes in the shape of the torsion spring. The restoring force of the torsion spring that resists the operating force that moves the movable plunger reaches its maximum value during the movement of the movable plunger. The movable optical path and the stationary optical path are aligned at a position of the movable plunger where the restoring force of the torsion spring is close to a maximum value.

FIG. 12 is a graph showing the relationship between restoring force and displacement of a torsion spring. As shown in FIG. 12, it is known that the restoring force of a torsion spring varies within elastic limits with respect to shape changes, or displacements, of the first and second free ends of the torsion spring.
It is disclosed in No. 4112284. That is, the restoring force of the torsion spring rapidly decreases after reaching a maximum value. In the present invention, this torsion spring phenomenon is utilized in the switch operating mechanism by setting the operating point of the switch slightly beyond its maximum value. This phenomenon is seen as a phenomenon of torsion spring retention and is called the snap-through effect or the fall-through effect.

In the mechanical operating mechanism of the present invention, the coil portion of the torsion spring is supported by a torsion spring support point provided on either the fixed member or the movable plunger. Also, the first and second torsion springs
The free ends of are in contact with first and second contact points provided on the other of the fixed member or the movable plunger. Torsion spring support points, first and second
The positional relationship of the three contact points changes relatively as the movable plunger slides. As a result, the shape of the torsion spring changes, and the restoring force of the torsion spring also changes. The restoring force of the torsion spring, which acts as a repulsive force against the operating force that moves the movable plunger, reaches a maximum value during the movement of the movable plunger. That is, during the switching operation of the switch, the resistance force against the operating force applied to the movable plunger increases and then decreases. Thereby, the person operating the movable plunger can obtain a tactile sensation that the resistance force of the movable plunger is reduced during the switching operation of the switch. Therefore, by appropriately setting the switching point of the switch during the movement of the movable plunger at the point where the restoring force of the torsion spring begins to decrease, it is possible to detect by tactile sensation that the switching operation has been performed. It becomes possible.

Further, according to the present invention, the switching operation of the switch is an operation of opening and closing the path of light emitted from the light source. Therefore, in the optical key switch of the present invention, the fixed member is provided with a fixed side optical path, and the movable plastic gear slidably held by the fixed member is provided with a moving side optical path. These moving side optical path and fixed side optical path are
The movable plunger is aligned during movement. Therefore, by aligning the movable side optical path and the fixed side optical path at the position of the movable plunger where the restoring force of the torsion spring is close to its maximum value, the opening/closing operation of the optical path becomes tactile. Detected by the senses.

That is, since the switching operation of the optical key switch, which is the object of the present invention, is based on the opening and closing operation of a light path inside the switch, it is difficult for the operator to recognize that the operation has been performed reliably. In order to ensure that the opening/closing operation of the light path is recognized, a torsion spring is utilized in the present invention. The restoring force of the torsion spring that resists the operating force that moves the movable plunger reaches a maximum value and then decreases. The light path is thus aligned at the point where it begins to decrease. Thereby, the alignment of the movable side optical path and the fixed side optical path, which is difficult for the operator to recognize, can be recognized by the operator's tactile sensation that the resistance force against the operating force of the movable plunger is reduced. As a result, the operator can accurately detect through his/her tactile sense that the opening/closing operation of the light path has been reliably performed.

Furthermore, in the present invention, the resistance force of the movable plunger against the operating force, that is, the restoring force of the torsion spring that rebounds against the operating force that moves the movable plunger, is determined by the shape change of the torsion spring. This twisting shape change is determined by the relative movement of the positional relationship between the support point and the first and second contact points. In the invention, the spacing between the first and second contact points is chosen such that it is always smaller than the spacing between the first and second free ends, regardless of changes in the shape of the torsion spring. That is, the first and second free ends always extend beyond the first and second contact points, and the contact points remain substantially fixed. Therefore, 3 of the torsion spring
Relative reciprocating movement of the positional relationship of points can be performed easily and with good reproducibility.

As a result, the shape of the torsion spring changes with the movement of the movable gear with good reproducibility. This allows the restoring force to change with good reproducibility in response to changes in the shape of the torsion spring. Therefore,
The relationship between key operating force and displacement of the movable plunger can be accurately determined.

Further, according to the present invention, the shape of the torsion spring changes from a shape in which the first and second free ends form an inferior angle to a shape in which the first and second free ends form a dominant angle. Therefore, it is possible to appropriately set the stroke of the movable plunger depending on the large angle range from the recessive angle to the dominant angle. At the same time, the key switch can be assembled when the angle formed by the first and second free ends is an inferior angle. In other words, the key switch can be assembled simply by applying a light force to the torsion spring as a preliminary load, which facilitates assembly. This effect can also be obtained when the key switch is disassembled.

Accordingly, an important object of this invention is to provide a removable key switch operating mechanism that has an extremely low profile without requiring low actuator support.

Another important object of this invention is to provide a key switch mechanism in which the tactile sensation is repeatable from key to key and remains constant and uniform over the wear life of the device. .

A further object of the invention is to provide a key switch actuator in which by varying the position of the actuator support member, i.e. the pivot point of the torsion spring, different force characteristics are produced in the same actuator means, i.e. the torsion spring. It is to provide the means.

Additional objects and advantages of this invention are that due to the shape of the torsion spring as opposed to the normal coil spring shape,
The spring lends itself very easily to automation of the key switch assembly, which is not the case with coil springs, which tend to become entangled with each other.

Another important object and feature of the invention is that the torsion spring is secured to the key axis within its key opening by the configuration of the end of the spring against the side wall of the support structure, particularly during the return stroke when the external force is removed. This means that there is a tendency to give self-centered decisions.

Other objects, features and advantages of the invention will be apparent from the following description, when considered with reference to the accompanying drawings, which illustrate by way of example, and not by way of limitation, the principles of the invention and a preferred mode of applying those principles. This will become clear in the following explanation.

[Brief explanation of drawings]

1, 4 and 5 are front cross-sectional views of the key operating mechanism of the present invention as incorporated into a photo-optical keyboard assembly.

FIG. 2 is a schematic diagram of one type of torsion spring used in the present invention.

Figure 2a shows the second part of the spring used in this invention.
The format is shown below.

FIG. 3 is a cross-sectional view of a portion of the structure of FIGS. 1, 4, and 5 in a preloaded or pretensioned state relative to the free state of FIG. FIG.

FIG. 6 is a force diagram of key operating force versus key stroke of the operating mechanism of the present invention.

FIG. 7 is a graph comparing various force load and travel combinations of various types of key operating mechanisms, with the operating mechanism of the present invention depicted in the central curve of the graph.

FIG. 8 is an isometric view of one type of operating mechanism as functionally incorporated in a keyswitch device.

FIG. 8a is a to-scale side view of one type of operating mechanism used in a keyswitch.

FIG. 9 is an isometric view similar to the view of FIG. 8, but differs therefrom in that the structural support forming the key axis has been modified in physical configuration.

Figure 9a is a top view of a portion of the keyboard, illustrating the orientation means to prevent key axes from shifting upon insertion into the keyboard;

10 and 11 are schematic illustrations of the basic functional operating mechanism embodying the invention, showing two different structural configurations for the torsion springs used therein.

FIG. 12 is a graph showing the relationship between the restoring force and displacement of the torsion spring used in the mechanical operating mechanism of the present invention.

BRIEF INVENTION OF PREFERRED EMBODIMENTS Referring to the drawings, the invention is illustrated in the periphery of a keyboard in which a plurality of vertically reciprocally movable keys are arranged in a matrix of rows and columns (in the figure one It is noted, however, that the operating mechanisms described therein and as such are useful in a wide variety of structural permutations and applications quite different from the keyboard itself.

Conventional practice in keyboard switch technology generally employs coil springs in the push type, where the spring is comprised of two opposed members, one fixed and the other movable relative to it. It was installed between. The force (actuation force) is varied during manufacture to adjust the preset pressure parameters or "feel". Usually, the pressing force is applied to the operating member,
For example, it increases with the degree or amount of press or stroke of a push button, key, etc. Attempts to create so-called "tactile sensations" have been relatively unsuccessful because, in standard keyswitches, it is difficult for the operator to determine by feel alone when the keyswitch contacts are closed. It was something.

The operating mechanism of the present invention, on the other hand, introduces and uses a torsion spring in a novel mechanism in which the operating force varies over a wide range of motion as the key switch actuator goes through its travel. In this way, the torsion spring can create a resisting force that first increases and then decreases such that its stroke effectively provides a "tactile sensation." Tactile sensation in this configuration is defined as a weakening or sudden decrease in the opposing force of pressure that creates or leads to a sensory sensation that decays from the initial pressure felt by the operator.
In this regard, it is also noted that the torsion spring may itself be wound or coiled to provide a varying spring force. Conversely, the attachment pivot point may be placed against the end of the torsion spring to effectively vary the required external operating force.

As best seen in the isometric view of FIG. 8 of the drawings, the operating mechanism 10 of the present invention includes a support member 1
2, the support member 12 of which has a top flat member 14 with a protruding edge 15 serving as a stop for the aperture or associated keyboard aperture described in more detail hereinafter, and having an external appearance. It may be substantially rectangular in form and may also be provided with vertically oriented free upright projections 16 and a solid bottom portion 18. Member 12
Opposite left and right vertical sidewall sections 20 and 2
2 smoothly terminates in a right rear vertical edge portion 24 which is chamfered as shown in the figures for purposes hereinafter described.

The member 10 shown in FIG. 8 is provided with a large central cutout 26. The member 10 shown in FIG. Projecting outwardly from the rear solid wall 28 into the cutout portion 26 and integrally provided is a post, stud or pivot member 30. Member 30 serves as a rotational mounting support or pivot for a pre-wound and pre-stressed torsion spring 37, as shown in FIGS. 2 and 3. In one structural configuration, spring 3
Coil No. 2 is wound counterclockwise as shown in Figure 2a. The direction of this initial coiling of spring 32 allows the spring to be used in a winding or unwinding direction as shown in FIGS. 8 and 9 for purposes described hereinafter.

Pivot 30 is located midway between the ends of support 12, and its location, as will be described, is used to vary the operation of the keys and the tactile sensation provided thereby. Spring member 32 is rotatably attached to member 30 in an arcuate manner. Both left and right ends 34 and 36 of torsion spring 32, respectively.
extends outwardly from its center and extends outwardly from the center of the drawing.
It is initially positioned at oppositely located left and right edges, 38 and 40, inside the support member 12 as best shown in the figures. As mentioned above, in its rest state, i.e. before being attached to the pivot 30, the spring is angled at its ends at approximately 90° so that the spring deflects sequentially through an arc of less than 360°.

As shown in the lower part of FIG.
As best shown in FIGS. 4 and 5, the support 12 includes a vertically extending cut 4.
2 is formed. This cut 42 extends from the bottom portion 18 to the lower portion of the central notch 26 and extends into the body of the member 12 substantially to the right to the center thereof to separate the lower portion of the member 12 into two identical halves 12a and 12a. Divided into 12b. These two halves are allowed to bend very slightly toward each other for purposes that will be explained later.
Discrete horizontal grooves 44, which are slightly oblate in configuration as shown in FIG. 8, extend across the front surface of member 12. The individual oblate apertures or apertures 46 extend completely through the body of the member 12 from front to back to form a groove extending therethrough.

The lower edge of each member 12a and 12b includes a chamfered edge 48 angled downwardly from a shelf or lip 50 extending from the front to the rear of the members 12a and 12b on its two sides. is provided. As shown in many of the drawings of FIGS. 1, 4 and 5, a shelf or lip 50
The member 12 may be fully inserted by being pushed into a substantially rectangular groove opening 52 (FIG. 4 and 5) provides a retention means for the member 12. In this case, the member 12 may be regarded as a key shaft. As shown, the key shaft has a series of substantially oblong cylindrical openings 44 extending therethrough.
and 46. These openings 44 and 46
is provided to irradiate or block light from a light source (not shown) to a detector (not shown) provided on the keyboard structure 54 itself. Thereby, keyboard structure 54 and member 12 are arranged for functional operation with a photo-optical keyboard.

FIG. 9 shows a modification of the structure shown and described in FIG. 8, and whose operating mechanism is substantially similar to that of FIG. 8, but in which the torsion spring is
8th when it is used in a key shaft mechanism
Whereas the torsion spring shown is "unwound", it is wound in the opposite direction so that the spring is "wound" in use. The support member or structure 56 of FIG. 9 includes a central vertical left and right structural wall or rib member 58 extending from side to side and orthogonally disposed front-to-back wall members or ribs 60. A rectangular member having a rectangular shape. The front portion of the rib 60 is cut out at the bottom as shown at 62;
An integrally forwardly extending pivot mounting support member 64 is provided for mounting a torsion spring 66 thereon. Both extending left and right ends 68 and 70, respectively, of spring 66 rest against edges 72 and 74 of member 56. Similar to member 12,
A plurality of horizontally extending oblate cylindrical grooves 76
is formed on member 56. A front-to-back oblate opening 78 is provided in the member of FIG. Part 1
A central vertical notch or slot 80, similar to the cutout portion 42 of 2, extends from the front surface of the member 56 to the central portion, and the member 56 is inserted into the receiving keyboard groove opening 52 of the keyboard with which it is operatively associated. Accordingly, this allows the capped lower portions 56a and 56b to be slightly compressed.

The lower portion of member 56 is beveled, as shown at 82, and shelves 84 are provided on either side of the lower portion of member 56, such that when it is located within an operatively associated keyboard, member 56 Acts as a retaining lip or stop for the "upward" movement of the Member 56 is provided with an upwardly projecting post 86 similar to member 16 of FIG. This vertically protruding member 86 allows
An alphanumeric display member, such as a key top (not shown), can be attached to this shaft portion. In order to reduce or avoid the possibility of mistakes in installing the correct key top on its associated key axle, a set of orientation grooves are provided on the 88
9, and one or more outwardly projecting tongues or steps 90 are provided on member 86, shown in FIG.
The manufacture of such equipment allows operators to
Alphabet numeric keys can be assembled onto a key shaft without fear of erroneously pointing the desired key in the wrong direction. The rear vertical edge on the right side corresponds to the angled corner 9 of each opening 52 in the keyboard 54.
It is chamfered as shown at 92 to engage 4. The flat top or lower edge portion 91 of member 56 provides a "downward" stop for key shaft 56 as it moves within member 54.

For purposes of this invention, it will be assumed that the operating mechanism of this invention is incorporated into an operating keyboard as shown in partial cross-sectional side views in FIGS. 1, 4, and 5 of the drawings. The torsion spring
After being pre-mounted on the pivot, with the end extending across the edge portion as shown in FIG. 3 of the drawings, the key pivot is then inserted into the lower body into the opening provided in the keyboard. It can be inserted into the main body of the keyboard by pressing on the section, so that its bifurcated end section can be inserted into the body of the keyboard so that the rim or ledge at the bottom of each key snap on the lower edge of the keyboard allows its spring to bent slightly towards each other until bent slightly into the position shown. For practical purposes, this position may be considered the preloaded position of the spring relative to the keyboard. As a key is pressed by an operator's finger, the movement of the key causes the spring to wrap around the pivot and the end of the spring to the exposed edge at the top of the opening in the keyboard into which the key is inserted. In a certain state, there is tension as shown in Figure 4. In the final position illustrated in FIG. 5, the destination position is reached in a downward movement within the keyboard. At the same time, the spring is bent to its upper limit. This performs the function of blocking and/or passing light at that point as it passes through the opening in the key structure, in accordance with the optical system contained within this structure.

Referring to the graph of FIG. 7, the operating mechanism of the present invention, represented by the line labeled P, has various stages in which the torsion spring is operable to produce the appropriate sensation of tactile sensation by the operator. Illustrate. Position 1 can be shown to be at the dotted line 90, to the left of the vertical solid line, where the spring is in its free state, (Fig. 2), and the position is approximately at the midpoint of the dotted line. , where the spring is mounted on a pivot. The third position is approximately at the beginning of the solid portion of curve P, where the spring is pre-attached to the keyboard or housing. As is obvious, by pressing the key in succession,
The force increases slightly and reaches a maximum at the top of curve P. After this, even though the operating force increases, the switch operates at a point Q slightly beyond the top dead center,
Closed or opened as the case may be. Then, the repulsive force begins to rapidly decrease until the operator begins to feel that the switch has been changed through the tactile sensation of a decrease in the repulsive force against the key operation force. Finally, at position V at the intersection of the second right dotted vertical line and the solid line, the switch is completely closed and its operation is complete. Thus, with the operating mechanism according to the invention, the switch is activated at a point slightly beyond its top dead center after the torsion spring has reached its maximum restoring force. After that, the recovery force of the torsion spring decreases rapidly. This relationship between compressive force and displacement is generally referred to as snap-through buckling. According to the operating mechanism of the present invention that takes advantage of this phenomenon, by selecting the operating point of the switch at the point where the spring recovery force begins to decrease, the operator feels the tactile sensation of a decrease in resistance force, and the operating point of the switch is adjusted. Can be detected.

As stated above, the basic concept involved in this invention is that the relative movement between a torque spring, a pivot for mounting the torque spring, the spring mounting means and the end of the spring is and means for movably mounting the ends of the spring so that both the amount and amount of force applied as well as the amount and extent of the resulting resistance force change and vary when .

Wide applications of this technology and structural combination are readily available to designers.

1. All mechanical devices that require a decreasing operating force relative to the stroke of the operating member that produces the operating force.

2. A keyboard switch as described above and in the claims.

3 Safety switches of various types.

4 Push button switch.

5 Control switches for external parts of equipment such as hazardous machinery and data processing equipment.

6. Various types of safety devices requiring electrical switch contact.

Referring to Figures 10a-10f and 11a-11f, the mechanism in this essential element, as best shown in the figures, employs the following.

1 a support member or shaft; 2 a torque spring having a coiled central portion and two oppositely disposed ends extending outwardly therefrom; (may be wound “CW” or counterclockwise “CCW”), and (3) abutting the end of a spring to provide relative movement between that end of the spring and its axis, and placed in such a way that relative movement between its axis and its abutting means changes the applied force required and changes the resulting force resisting that change. means.

As a basic assembly, the invention comprises a base 94 that acts as a support structure for a reciprocating and vertically movable shaft or plunger-like member 96, as shown in FIGS. 10a-10f.
Shown schematically in the figure. Member 94 includes two parallel separate upright protrusions or tongues 98 having non-interfering upper end portions that are rounded as shown for convenience. The shaft 96 is provided with a vertically dependent projection or tongue 100 . Its lowest end supports a horizontally forwardly extending stud 102 which acts as a mounting pivot for a torsion spring 104. The coiled central portion of the torsion spring 104 is attached to the pivot stud 102 and is allowed to rotate freely thereabout up to a predetermined limit of the spring 104. 94
The means for retaining member 96 against is not shown, but may be accomplished by any of several well-known techniques.

10 each of the right and left free ends of the spring 104
6 and 108 abut the uppermost rounded portion of the respective vertical tongue portion 98. Member 96 is freely movable vertically up and down and reciprocatingly in a telescopic manner between upper sidewalls 110 of member 94, as described with reference to FIG. For explanation, the 10th
Assume that the spring 102 in figure a is in an untensioned or unloaded state. This position is the negative point on the curve in Figure 6.
Corresponds to 15° position. As member 96 begins its downward movement relative to member 94, the stress in its spring begins to increase as in FIG. 10b, which is approximately negative in the curve of FIG.
Corresponds to the position at 7° position. Further downward movement of member 96 brings the spring force to the position of FIG. 10c, which corresponds to approximately 0° of the curve of FIG. 6.
FIG. 10d approximately corresponds to the 5° position of the curve in FIG. Figure 10e corresponds to approximately the 21° position of the curve in Figure 6, and Figure 10f corresponds to the approximately 21° position of the curve in Figure 6.
Figure 2 schematically shows the device in the so-called bottom or lowest position corresponding to the 75° position. In addition, the fifth
The figure corresponds to a position between FIGS. 10e and 10f. Of course, each of these positions can be selectively defined, and such positions and forces can be applied to abutment members 106 and 10 relative to the pivot.
8 can be selectively changed by changing the position of both pivots relative to member 96.

In addition, the straight line located on the lower side in Fig. 6 is
It follows the straight line located on the upper side. That is, the change in key operating force between 25° and 55° is not shown. Also, when the value of the angle attached to the straight line is 0°, the first and second torsion springs
The angle formed by the free end of the angle changes from a recessive angle to a dominant angle. The position corresponding to 75° in FIG. 6 corresponds to position V in FIG. The position slightly later than 25° in FIG. 6 (not shown in FIG. 6) corresponds to Q in FIG.

11a-11f are substantially similar to those of FIGS. 10-10f, the difference being that the pivot stud 112
4 is located on the fixing member 110 forming a mounting pivot. The left and right spring ends 116 and 118 abut rightward and leftward projecting tongues 120 and 122, respectively, which are integral with the moving member 124. Chapter 11a
As shown in Figures 11f, substantially the same force is applied to the set of curves in Figure 6, but the torsion spring 114 has its ends 116 and 118 expanded in opposite directions. Not done.