Press input device

Abstract

This pressing input device is an input device the reaction force characteristic of which when a single metallic inverted dome is pushed downward is a first reaction force characteristic that reaction force increases monotonously from an initial position to a maximum position, decreases monotonously from the maximum position to a minimum position, and increases monotonously from the minimum position, the reaction force characteristic of which when a single elastic member is pushed downward is a second reaction force characteristic that reaction force increases monotonously from the initial position, and the reaction force characteristic of which when an operation member is displaced downward is a synthesized reaction force characteristic obtained by synthesizing the first reaction force characteristic and the second reaction force characteristic, wherein a plate-shaped intermediate member having a larger area than the elastic member when viewed from above is provided between the metallic inverted dome and the elastic member, and the elastic member comprises a metallic plate spring member having a peripheral portion that is in contact with the plate-shaped intermediate member and a central portion that is away from the plate-shaped intermediate member.

Description

Technical Field

[0001] The present invention relates to a pressing input device.

Background Art

[0002] In Patent Document 1 below, in a push-on switch configured to reversibly operate a reversibly operating movable contact by a push button, a pressing elastic body is provided at the center of the lower surface of the push button, and the reversibly operating movable contact is pressed through the pressing elastic body to reversibly operate it. Thus, prior to the reversible operation of the reversibly operating movable contact, the pressing elastic body is deformed (shrunk) by a predetermined amount, and a technique for increasing the operating stroke by this amount is disclosed.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique of Patent Document 1, since the stroke amount (S5 - S4) of the push button during the reversible operation of the reversibly operating movable contact is equal to the stroke amount (S2 - S1) during the reversible operation of a single reversibly operating movable contact, it is difficult to further shorten the stroke amount of the push button during the reversible operation of the reversibly operating movable contact. Therefore, a crisp operation feeling cannot be presented to the operator.

Means for Solving the Problems

[0005] A pressing input device according to one embodiment comprises a housing having a first housing section, a central fixed contact provided at the bottom of the first housing section, a base, a metal inversion dome installed above the base, an elastic member installed above the metal inversion dome, and an operating member installed above the elastic member and supported so as to be displaceable downward. The reaction force characteristics when a single metal inversion dome is pushed downward are that the reaction force increases monotonically from the initial position to the maximum position, decreases monotonically from the maximum position to the minimum position, and increases monotonically thereafter. The input device has a first reaction force characteristic, the reaction force characteristic when a single elastic member is pushed downward is a second reaction force characteristic in which the reaction force monotonically increases from the initial position, and the reaction force characteristic when the operating member is displaced downward is a combined reaction force characteristic which is a combination of the first and second reaction force characteristics. A plate-shaped intermediate member, which has a larger area than the elastic member when viewed from above, is provided between a metal inversion dome and an elastic member, and the elastic member consists of a metal plate spring member whose peripheral portion abuts against the plate-shaped intermediate member and whose central portion is separated from the plate-shaped intermediate member. [Effects of the Invention]

[0006] According to one embodiment of the press input device, a crisp and responsive operating feel can be presented to the operator. [Brief explanation of the drawing]

[0007] [Figure 1] External perspective view of a push input device according to one embodiment. [Figure 2] Exploded perspective view of a press input device according to one embodiment. [Figure 3] Cross-sectional view of a press input device according to one embodiment. [Figure 4] A diagram illustrating the operation of a push-button input device according to one embodiment. [Figure 5] This figure shows the reaction force characteristics of a pressing input device according to one embodiment. [Modes for carrying out the invention]

[0008] An embodiment will be described below with reference to the drawings. For convenience, in the following description, the Z-axis direction in the drawings will be considered as the vertical direction, the Y-axis direction as the left-right direction, and the X-axis direction as the front-back direction. However, the positive Z-axis direction will be considered upward, the positive Y-axis direction as the rightward direction, and the positive X-axis direction as the forward direction.

[0009] (Overview of the press input device 100) Figure 1 is an external perspective view of a press input device 100 according to one embodiment. As shown in Figure 1, the press input device 100 has a generally thin rectangular parallelepiped shape in the vertical direction (Z-axis direction), and is roughly square in top view.

[0010] As shown in Figure 1, the pressing input device 100 has a housing 110 whose upper surface 110A is covered by a frame 120. The housing 110 houses a stem 130 and the like. An operating part 131 is provided in the center of the stem 130, which protrudes upward (in the positive Z-axis direction).

[0011] The operating portion 131 of the stem 130 penetrates a circular opening 120A formed in the frame 120 and protrudes upward (in the positive Z-axis direction) above the frame 120. As a result, the press input device 100 can be pressed downward (in the negative Z-axis direction) by the operating portion 131 of the stem 130, and this pressing operation can switch the device from the switch-off state to the switch-on state.

[0012] (Configuration of the pressing input device 100) Figure 2 is an exploded perspective view of a press input device 100 according to one embodiment. Figure 3 is a cross-sectional view of the press input device 100 according to one embodiment. As shown in Figures 2 and 3, the press input device 100 comprises, in order from the bottom (negative Z-axis side) in the figures, a housing 110, a metal inverted dome 140, a plate-shaped intermediate member 150, an elastic member 160, a stem 130, and a frame 120.

[0013] The housing 110 is an example of a "base." The housing 110 is a container-like member having a thin rectangular parallelepiped shape in the vertical direction (Z-axis direction). When viewed from above, the housing 110 has a roughly square shape. The housing 110 has a recess 110B that is recessed downwards from the top surface 110A. Inside the recess 110B, in order from the bottom (negative Z-axis side), a metal inverted dome 140, a plate-shaped intermediate member 150, an elastic member 160, and a stem 130 are housed. For example, the housing 110 is formed by insert molding using a relatively hard insulating material (e.g., hard resin).

[0014] Each of the left and right sides of the housing 110 has a claw portion 111 that protrudes outward. When the frame 120 is attached to the upper surface 110A of the housing 110, the claw portion 111 is fitted into the opening 120Ba of the hook 120B of the frame 120, and by engaging with the hook 120B, the frame 120 can be fixed to the housing 110.

[0015] The bottom portion 110Ba within the recess 110B of the housing 110 is provided with a central fixed contact 112 and four peripheral fixed contacts 113. The central fixed contact 112 is located in the center of the bottom portion 110Ba. The four peripheral fixed contacts 113 are located at the four corners of the bottom portion 110Ba. Both the central fixed contact 112 and the peripheral fixed contacts 113 are formed using a conductive material (for example, a metal material).

[0016] The metal inverted dome 140 is a thin, plate-like metal member positioned on the bottom 110Ba within the recess 110B of the housing 110. The metal inverted dome 140 has a dome shape that is convex upward (in the positive Z-axis direction) with a apex 140A in the center. In addition, the metal inverted dome 140 has a roughly square shape when viewed from above.

[0017] At each of the four corners on the outer peripheral edge of the metal reversing dome 140, legs 141 protruding outward in the radial direction are provided. The metal reversing dome 140 is disposed on the bottom 110Ba of the recess 110B of the housing 110, so that each of the four legs 141 contacts each of the four peripheral fixed contacts 113 provided on the bottom 110Ba of the recess 110B of the housing 110.

[0018] The metal reversing dome 140 is a so-called "reversing spring". When a pressing operation is performed on the operation portion 131 of the stem 130, the top portion 140A is pressed downward by the plate-shaped intermediate member 150, and when a predetermined operating load is exceeded, the top portion 140A suddenly elastically deforms (reversing operation) into a concave shape. As a result, the metal reversing dome 140 contacts the central fixed contact 112 at the back side of the top portion 140A and is electrically connected to the central fixed contact 112. As a result, the metal reversing dome 140 can conduct the central fixed contact 112 and the peripheral fixed contact 113 to each other through the metal reversing dome 140. When the pressing operation by the operation portion 131 of the stem 130 is released, the metal reversing dome 140 returns to its original convex shape by elastic force.

[0019] <( The metal reversing dome 140 may have a circular shape in a top view, or may not have the legs 141.

[0020] The plate-shaped intermediate member 150 is a flat plate-shaped member disposed between the metal reversing dome 140 and the elastic member 160. The plate-shaped intermediate member 150 has a substantially square shape with a larger area than the elastic member 160 in a top view. The plate-shaped intermediate member 150 is a so-called rigid body and is formed by using a relatively hard material (for example, a resin material, a metal material, etc.). <00\00094>

[0021] As shown in FIG. 3, the plate-shaped intermediate member 150 has a pressing portion 151 provided to protrude downward at the central portion of the bottom surface. The pressing portion 151 is a portion that presses the top portion 140A of the metal reversing dome 140 when a pressing operation is performed on the operation portion 131 of the stem 130.

[0022] Furthermore, the upper surface of the plate-shaped intermediate member 150 is a flat surface 150A on which the elastic member 160 is installed.

[0023] The elastic member 160 is a thin, plate-like metal member installed on the flat surface 150A of the plate-shaped intermediate member 150. The elastic member 160 has a dome shape that is convex upward (in the positive Z-axis direction) with a apex 160A in the center. In addition, the elastic member 160 has a roughly square shape when viewed from above.

[0024] Each of the four corners on the outer edge of the elastic member 160 is provided with a leg portion 161 that protrudes radially outward. The elastic member 160 is a "metal leaf spring member" such that when it is placed on the flat surface 150A of the plate-shaped intermediate member 150, each of the four legs 161 (an example of the "peripheral portion") abuts against the flat surface 150A of the plate-shaped intermediate member 150, and the top portion 160A (an example of the "center portion") is separated from the flat surface 150A of the plate-shaped intermediate member 150.

[0025] When the elastic member 160 is pressed by the operating part 131 of the stem 130, its top portion 160A is pressed downward by the pressing part 133 of the stem 130, causing it to elastically deform and gradually be crushed while applying an operating load to the stem 130. When the back side of the top portion 160A of the elastic member 160 comes into contact with the flat surface 150A of the plate-shaped intermediate member 150, the elastic member 160 becomes horizontal (i.e., completely crushed). At this time, the operating load applied by the elastic member 160 to the stem 130 is at its maximum. When the pressing operation by the operating part 131 of the stem 130 is released, the elastic member 160 returns to its original convex shape due to its elastic force.

[0026] The elastic member 160 may have a circular shape when viewed from above, and may not have legs 161.

[0027] The stem 130 is an example of an "operating member" and is pressed downward by the operator. For example, the stem 130 is formed using a relatively hard insulating material (e.g., hard resin). The stem 130 has an operating part 131, a support part 132, and a pressing part 133.

[0028] The operating section 131 is located in the center of the stem 130, has a cylindrical shape that protrudes upward from the support section 132, and is the part that is pressed by the operator.

[0029] The support portion 132 is a flat plate-shaped part provided around the operating portion 131. The support portion 132 is provided integrally with the operating portion 131 and supports the operating portion 131. The support portion 132 has a roughly square shape when viewed from above.

[0030] The pressing portion 133 is provided protruding downward from the center of the bottom surface of the stem 130. The pressing portion 133 is the part that presses the top portion 160A of the elastic member 160 when a pressing operation is performed by the operating portion 131 of the stem 130.

[0031] The stem 130 is positioned between the frame 120 and the elastic member 160, with the operating portion 131 passing through the opening 120A of the frame 120 and the pressing portion 133 in contact with the top portion 160A of the elastic member 160.

[0032] The frame 120 is a flat, metal member. The frame 120 is fixedly attached to the upper surface 110A of the housing 110, thereby closing the upper opening of the recess 110B of the housing 110 while the components (metal inverted dome 140, plate-shaped intermediate member 150, elastic member 160, and stem 130) are housed within the recess 110B of the housing 110.

[0033] For example, the frame 120 is formed by processing a metal plate using a method such as press working. In a top view, a circular opening 120A is formed in the center of the frame 120 to allow the operating portion 131 of the stem 130 to protrude upward. In addition, a pair of hooks 120B hanging downward are provided on each of the left and right sides of the outer edge of the frame 120. The hooks 120B have an opening 120Ba into which a claw portion 111 provided on the side of the housing 110 is fitted. In this way, the hooks 120B can fix the frame 120 to the housing 110.

[0034] (Operation of the press input device 100) Figure 4 is a diagram illustrating the operation of a press input device 100 according to one embodiment.

[0035] In one embodiment of the press input device 100, as shown in Figure 4(a), when no pressing operation is performed by the operating part 131 of the stem 130, the elastic member 160 and the metal inverted dome 140 are in an initial state of being convex upward. Therefore, the metal inverted dome 140 is in contact with the peripheral fixed contact 113 but not with the central fixed contact 112. In other words, the peripheral fixed contact 113 and the central fixed contact 112 are not electrically connected to each other. For this reason, when no pressing operation is performed by the operating part 131 of the stem 130, the press input device 100 in one embodiment is in an off state.

[0036] In one embodiment of the pressing input device 100, as shown in Figure 4(b), when a pressing operation is performed by the operating part 131 of the stem 130, the pressing part 133 of the stem 130 pushes down the top 160A of the elastic member 160. As a result, the elastic member 160 elastically deforms, and the elastic member 160 pushes down the plate-shaped intermediate member 150. Furthermore, the pressing part 151 of the plate-shaped intermediate member 150 pushes down the top 140A of the metal inverted dome 140, causing the elastic member 160 to elastically deform.

[0037] Furthermore, in one embodiment of the press input device 100, as shown in Figure 4(c), when the operating load of the press operation by the operating part 131 of the stem 130 exceeds a predetermined threshold (i.e., when the stroke amount of the stem 130 exceeds the top stroke amount), the elastic member 160 is completely compressed, and the top portion 140A of the metal inverted dome 140 elastically deforms into a concave shape (inverting operation). As a result, the stroke amount of the stem 130 becomes the bottom stroke amount, and the metal inverted dome 140 is electrically connected to the central fixed contact 112 by the back side of the top portion 140A coming into contact with the central fixed contact 112.

[0038] As a result, in one embodiment, the press input device 100 switches on when the central fixed contact 112 and the peripheral fixed contact 113 become electrically connected to each other via the metal inverting dome 140. At this time, the press input device 100 in one embodiment can provide a click sensation in response to the pressing operation by the pressing part 133 of the stem 130 by the inverting operation of the metal inverting dome 140. Therefore, the press input device 100 in one embodiment can allow the operator to tactilely understand that it has switched on.

[0039] In one embodiment of the press input device 100, when the pressing operation by the pressing portion 133 of the stem 130 is released, the elastic member 160 returns to its original convex shape due to its own elastic force, and the metal inverted dome 140 also returns to its original convex shape due to its own elastic force. As a result, the press input device 100 according to one embodiment returns to the switch-off state.

[0040] (Reaction force characteristics of the pressing input device 100) Figure 5 shows the reaction force characteristics of a pressing input device 100 according to one embodiment. Figure 5(a) shows an example of the reaction force characteristics when a single elastic member 160 is pressed downward. Figure 5(b) shows an example of the reaction force characteristics when a single metal inverted dome 140 is pressed downward. Figure 5(c) shows an example of the reaction force characteristics when the reaction force characteristics of the single elastic member 160 and the reaction force characteristics of the single metal inverted dome 140 are combined. In each graph shown in Figure 5, the vertical axis represents the reaction force [N], and the horizontal axis represents the stroke amount [mm] of the pressing operation.

[0041] As shown in Figure 5(b), when a single metal inverted dome 140 is pushed downward, the reaction force characteristics are as follows: the reaction force increases monotonically from the initial position to the maximum position N1, decreases monotonically from the maximum position N1 to the minimum position N2, and then increases monotonically thereafter. This is a first reaction force characteristic.

[0042] Furthermore, as shown in Figure 5(a), the reaction force characteristics when a single elastic member 160 is pushed downward are second reaction force characteristics in which the reaction force increases monotonically from the initial position to the maximum position N1. However, in the second reaction force characteristics, the reaction force of the single elastic member 160 increases more steeply than the reaction force of the single metal inverted dome 140.

[0043] Furthermore, in one embodiment of the pressing input device 100, an elastic member 160 is provided above the metal inversion dome 140 via a plate-shaped intermediate member 150, and since the elastic member 160 is made of a "metal plate spring member", when the stem 130 is displaced downward (i.e., when a pressing operation is performed by the operating part 131 of the stem 130), the reaction force characteristics are a composite reaction force characteristic, as shown in Figure 5(c), which is a combination of the first reaction force characteristic shown in Figure 5(b) and the second reaction force characteristic shown in Figure 5(a).

[0044] As shown in Figure 5(c), the above resultant reaction force characteristics show a gradual increase in reaction force from the initial position to the maximum position N1, and a steep decrease in reaction force from the maximum position N1 to the minimum position N2. In other words, the above combined reaction force characteristics have a short stroke amount from the maximum position N1 to the minimum position N2 (i.e., the stroke amount of the stem 130 during the reversal operation of the metal inverting dome 140).

[0045] For example, as shown in Figure 5(b), the top stroke amount in the first reaction force characteristic is denoted as S2', and the bottom stroke amount in the first reaction force characteristic is denoted as S1'.

[0046] Furthermore, as shown in Figure 5(a), the top stroke amount in the second reaction force characteristic described above is denoted as S2, and the bottom stroke amount in the first reaction force characteristic described above is denoted as S1.

[0047] In this case, as shown in Figure 5(c), the top stroke amount of the stem 130 in the above combined reaction force characteristics is (S2 + S2'), and the bottom stroke amount in the above combined reaction force characteristics is (S1 + S1').

[0048] As a result, the pressing input device 100 according to one embodiment can make the stroke amount from the maximum position N1 to the minimum position N2 in the combined reaction force characteristics ((S1+S1')-(S2+S2')) shorter than the stroke amount from the maximum position N1 to the minimum position N2 in the single metal inversion dome 140 (S1'-S2'), as shown in Figure 5(c). Therefore, it is possible to shorten the stroke amount of the stem 130 during the inversion operation of the metal inversion dome 140. For example, in the example shown in Figure 5(c), the stroke amount of the stem 130 during the inversion operation of the metal inversion dome 140 is reduced to approximately 0.03 mm.

[0049] As a result, the pressing input device 100 according to one embodiment can rapidly reduce the drop in reaction force from the maximum position N1 to the minimum position N2 in the above-mentioned combined reaction force characteristics, as shown in Figure 5(c), and thus can provide the operator with a crisp and responsive feel.

[0050] Furthermore, in the pressing input device 100 according to one embodiment, the elastic member 160 hardly bends in the overstroke region (the region from the minimum position N2 onwards) in the above-mentioned combined reaction force characteristics, so even in the overstroke region, it is possible to shorten the stroke amount of the stem 130.

[0051] In particular, as shown in Figure 5(c), the pressing input device 100 according to one embodiment can make the decrease in reaction force per unit displacement from the maximum position N1 to the minimum position N2 in the composite reaction force characteristics greater than the decrease in reaction force per unit displacement from the maximum position N1 to the minimum position N2 in the first reaction force characteristics.

[0052] As a result, the pressing input device 100 according to one embodiment can rapidly reduce the drop in reaction force from the maximum position N1 to the minimum position N2 in the above-mentioned combined reaction force characteristics, thereby providing the operator with a crisp and responsive feel.

[0053] Furthermore, in the pressing input device 100 according to one embodiment, the second reaction force characteristic of the single elastic member 160 is such that after the reaction force becomes equal to the reaction force at the maximum position N1 of the single metal inverted dome 140, the increase in the amount of reaction force per unit displacement rises sharply. This is because, after the reaction force of the second reaction force characteristic becomes equal to the reaction force at the maximum position N1 of the single metal inverted dome 140, the elastic member 160 is completely compressed and does not bend any further.

[0054] As a result, the pressing input device 100 according to one embodiment can achieve both a shorter stroke length for the stem 130 and a lower profile for the entire pressing input device 100.

[0055] Furthermore, in the pressing input device 100 according to one embodiment, the vertical dimension (Z-axis direction) of the elastic member 160 is smaller than the vertical dimension (Z-axis direction) of the metal inversion dome 140.

[0056] As a result, the pressing input device 100 according to one embodiment can achieve further reduction in the overall height of the pressing input device 100.

[0057] Furthermore, in the pressing input device 100 according to one embodiment, the plate-shaped intermediate member 150 has a flat surface 150A on which the elastic member 160 is installed.

[0058] As a result, the pressing input device 100 according to one embodiment can achieve further reduction in the overall height of the pressing input device 100.

[0059] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to these embodiments, and various modifications or changes are possible within the scope of the gist of the present invention as described in the claims.

[0060] This international application claims priority based on Japanese Patent Application No. 2022-154570, filed on 28 September 2022, and the entire contents of said application are incorporated herein by reference. [Explanation of Symbols]

[0061] 100 Press input device 110 Housing (Base) 110A top 110B recess 110Ba bottom 111 Nail area 112 Central fixed contact 113 Peripheral fixed contacts 120 frames 120A opening 120B Hook 120Ba opening 130 Stem (operating component) 131 Operation section 132 Support part 133 Pressing part 140 Metal inverted dome 140A top 141 Legs 150 Plate-shaped intermediate member 150A flat surface 151 Pressing part 160 Elastic component (metal leaf spring component) 160A Top (Center) 161 Legs (peripheral area)

Claims

1. Base and, A metal inverting dome is installed above the aforementioned base, An elastic member installed above the aforementioned metal inversion dome, The system comprises an operating member installed above the elastic member and supported so as to be displaceable downward, The reaction force characteristics when the single metal inverted dome is pushed downward are as follows: the reaction force increases monotonically from the initial position to the maximum position, decreases monotonically from the maximum position to the minimum position, and then increases monotonically thereafter; this is the first reaction force characteristic. The reaction force characteristics when the elastic member is pushed downward are second reaction force characteristics in which the reaction force increases monotonically from the initial position. An input device in which the reaction force characteristics when the operating member is displaced downward are combined reaction force characteristics obtained by combining the first reaction force characteristics and the second reaction force characteristics, Between the metal inverting dome and the elastic member, a plate-shaped intermediate member is provided with a larger surface area than the elastic member when viewed from above. The elastic member is a metal plate spring member whose peripheral portion abuts against the plate-shaped intermediate member and whose central portion is separated from the plate-shaped intermediate member. The decrease in reaction force per unit displacement from the maximum position to the minimum position in the combined reaction force characteristic is greater than the decrease in reaction force per unit displacement from the maximum position to the minimum position in the first reaction force characteristic. A pressure input device characterized by the following features.

2. A base and, A metal inverting dome is installed above the aforementioned base, An elastic member installed above the aforementioned metal inversion dome, The system comprises an operating member installed above the elastic member and supported so as to be displaceable downward, The reaction force characteristics when the single metal inverted dome is pushed downward are as follows: the reaction force increases monotonically from the initial position to the maximum position, decreases monotonically from the maximum position to the minimum position, and then increases monotonically thereafter; this is the first reaction force characteristic. The reaction force characteristics when the elastic member is pushed downward are second reaction force characteristics in which the reaction force increases monotonically from the initial position. An input device in which the reaction force characteristics when the operating member is displaced downward are combined reaction force characteristics obtained by combining the first reaction force characteristics and the second reaction force characteristics, Between the metal inverting dome and the elastic member, a plate-shaped intermediate member is provided with a larger surface area than the elastic member when viewed from above. The elastic member is a metal plate spring member whose peripheral portion abuts against the plate-shaped intermediate member and whose central portion is separated from the plate-shaped intermediate member. The second reaction force characteristic of the individual metal leaf spring member is characterized in that, after the reaction force becomes equal to the reaction force at the maximum position of the individual metal inverted dome, the amount of increase in the reaction force per unit displacement rises sharply.

3. A base and, A metal inverting dome is installed above the aforementioned base, An elastic member installed above the aforementioned metal inversion dome, The system comprises an operating member installed above the elastic member and supported so as to be displaceable downward, The reaction force characteristics when the single metal inverted dome is pushed downward are as follows: the reaction force increases monotonically from the initial position to the maximum position, decreases monotonically from the maximum position to the minimum position, and then increases monotonically thereafter; this is the first reaction force characteristic. The reaction force characteristics when the elastic member is pushed downward are second reaction force characteristics in which the reaction force increases monotonically from the initial position. An input device in which the reaction force characteristics when the operating member is displaced downward are combined reaction force characteristics obtained by combining the first reaction force characteristics and the second reaction force characteristics, Between the metal inverting dome and the elastic member, a plate-shaped intermediate member is provided with a larger surface area than the elastic member when viewed from above. The elastic member is a metal plate spring member whose peripheral portion abuts against the plate-shaped intermediate member and whose central portion is separated from the plate-shaped intermediate member. A pressing input device characterized in that the vertical dimension of the metal leaf spring member is smaller than the vertical dimension of the metal inverting dome.

4. The pressing input device according to any one of claims 1 to 3, characterized in that the plate-shaped intermediate member has a flat surface on which the metal plate spring member is installed.

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