Support device

Abstract

The present invention provides a supporting device (10) which can rotatably support a supporting object (W) without rotating itself. The support device (10) includes: a base portion (12); a pair of support members (14) which are slidably arranged relative to the base portion (12) and are provided with arc-shaped cutout portions (28) of a circumferential surface (32) for clamping a support object (W) from both sides; a plurality of first force-applying members (16) which apply force to the pair of support members (14) in a direction of approaching each other; a bearing portion (18) which is provided with a plurality of bearings along the cutout portions (28) for clamping the support object (W) in a manner that the support object (W) can rotate; and a plurality of second force-applying members (20) which apply force to the plurality of bearing portions (18) toward the support object (W), wherein the plurality of bearing portions (18) clamp the support object (W) with a force stronger than the force applied by the plurality of first force-applying members (16) to the pair of support members (14).

Description

Technical Field

[0001] The present invention relates to a supporting device for supporting an object having a circumferential surface. Background Art

[0002] Supporting devices such as air chucks provided to support a support object are generally known. In addition, a rotary joint that rotates a support object and a supporting device supporting the support object is also known. One example is disclosed in Japanese Patent Utility Model Publication No. 05-053886. Summary of the invention

[0003] As described in the premise of Japanese Patent Utility Model Publication No. 05-053886, a general support device rotates together with the support object when the support object is rotated by a rotary joint. In such a support device, for example, in a limited space, the need to rotate only the support object without rotating the support device cannot be met.

[0004] Therefore, an object of the present invention is to provide a support device that can rotatably support a support object without rotating itself.

[0005] One embodiment of the present invention is a support device for supporting a support object having a circumferential surface, which comprises: a base portion; a pair of support members, which are slidably arranged relative to the base portion and are provided with arc-shaped cutout portions for clamping the circumferential surface from both sides; a plurality of first force-applying members, which apply force to the pair of support members in directions of approaching each other; a plurality of bearing portions, which are arranged along the respective cutout portions of the pair of support members and are used to clamp the support object in a manner that the support object can rotate around the axis of the support object; and a plurality of second force-applying members, which apply force to the plurality of bearing portions toward the support object in order to enable the plurality of bearing portions to clamp the support object, wherein the force of the plurality of first force-applying members and the force of the plurality of second force-applying members are set so that the plurality of bearing portions can clamp the support object with a force stronger than the force applied to the pair of support members by the plurality of first force-applying members.

[0006] According to the present invention, there is provided a support device that rotatably supports a support object without rotating itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a perspective view of the support device according to the embodiment.

[0008] Figure 2 It is a top view of the support device according to the embodiment.

[0009] Figure 3It is a bottom view of the support device according to the embodiment.

[0010] Figure 4 This is a perspective view showing a state in which a support object is arranged between two cutout portions.

[0011] Figure 5 yes Figure 2 VV cross-section diagram.

[0012] Figure 6 This is a first diagram for explaining how a pair of supporting members clamp a supported object.

[0013] Figure 7 This is a second diagram for explaining how a pair of supporting members clamp an object to be supported.

[0014] Figure 8 This is a first diagram for explaining how a plurality of bearings hold a supported object.

[0015] Fig. 9 This is a second diagram for explaining how a plurality of bearings hold a supported object.

[0016] Fig.10 It is a diagram for explaining the structure of the support device according to Modification 1.

[0017] Fig.11 yes Fig.10 XI-XI section view. DETAILED DESCRIPTION

[0018] The support device of the present invention will be described in detail below with reference to the drawings, with reference to preferred embodiments thereof.

[0019] [Implementation Method]

[0020] Figure 1 It is a perspective view of the support device 10 according to the embodiment. Figure 2 It is a top view of the support device 10 according to the embodiment. Figure 3 It is a bottom view of the support device 10 of the embodiment. In addition, each direction of up, down, left, right, front and back described below follows the arrows shown in each drawing.

[0021] The support device 10 of the present embodiment is for supporting an object W having a circumferential surface 32 ( Figure 4 The support device 10 includes a base portion 12, a pair of support members 14, a plurality of first force applying members 16, a plurality of bearing portions 18, a plurality of second force applying members 20, an actuator 22, and a control portion 24. These elements will be described below.

[0022] The base 12 is a plate-shaped member made of metal. The base 12 illustrated in this embodiment has long sides in the left-right direction and short sides in the front-back direction, but the base 12 is not limited to the structure having long sides and short sides.

[0023] A hole 26 is provided in the center of the base 12, which passes through the base 12 in the thickness direction (vertical direction). The hole 26 achieves the following two points: ensuring visibility of the supported object W clamped by the pair of supporting members 14 or the plurality of bearings 18 described later, and making the tool T ( Fig. 9 ) etc. can easily approach the supporting object W.

[0024] The pair of support members 14 are opposite to each other in the left-right direction and have a left support member 14A and a right support member 14B that are symmetrically configured. The pair of support members 14 are respectively substantially flat metal members that are slidably disposed relative to the base portion 12, and are provided with arc-shaped cutouts 28. The cutouts 28 are disposed on the side surface on the right side opposite to the right support member 14B in the left support member 14A, and are disposed on the side surface on the left side opposite to the left support member 14A in the right support member 14B. Thus, the two cutouts 28 are opposite to each other in the left-right direction.

[0025] A plurality of radially long holes 28s for slidably placing the bearing 18 described later are formed on the surface of the cutout portion 28. The arrangement of the plurality of long holes 28s provided on the left support member 14A and the arrangement of the plurality of long holes 28s provided on the right support member 14B are symmetrical. In addition, radially slits may be formed on the cutout portion 28 instead of the long holes 28s.

[0026] In addition, it is preferable that a concavo-convex shape 30 is formed along the up-down direction on the surface of the cutout portion 28. The reason for this will be described later.

[0027] In this embodiment, the supporting object W is a screw member having a round head. However, the supporting object W is not limited to the screw member, and may be, for example, a simple cylindrical member. In addition, the circumferential surface 32 of the supporting object W includes not only a circular end surface but also a circular cross section. The supporting object W has an axis 34 passing through the center of the circumferential surface 32.

[0028] The plurality of first force applying members 16 apply force to the pair of support members 14 in the approaching direction. The approaching direction is a direction parallel to the relative direction of the pair of support members 14, that is, a direction in which the pair of support members 14 approach each other. That is, the approaching direction refers to the right direction toward the right support member 14B for the left support member 14A, and refers to the left direction toward the left support member 14A for the right support member 14B.

[0029] In the present embodiment, the plurality of first urging members 16 are respectively compression coil springs having elasticity, but the plurality of first urging members 16 are not limited to compression coil springs as long as they are structures that urge the pair of support members 14 .

[0030] In the present embodiment, two first biasing members 16 are connected to each of the pair of support members 14. Among them, one end 16a of the first biasing member 16 connected to the left support member 14A is connected to the side of the left support member 14A opposite to the right support member 14B, and the other end 16b is connected to the base portion 12. Similarly, one end 16a of the first biasing member 16 connected to the right support member 14B is connected to the side of the right support member 14B opposite to the left support member 14A, and the other end 16b is connected to the base portion 12.

[0031] like Figure 3 As shown, the two first force applying members 16 connected to the left side support member 14A form a pair with each other in the front-rear direction relative to the left side support member 14A. As a result, the force applied to the left side support member 14A from the first force applying member 16 connected to the left side support member 14A and the force applied to the left side support member 14A from the other first force applying member 16 become equal.

[0032] Similarly, the two first force applying members 16 connected to the right side support member 14B form a pair with each other in the front-rear direction relative to the right side support member 14B. Thus, the force applied to the right side support member 14B from the first force applying member 16 connected to the right side support member 14B and the force applied to the right side support member 14B from the other first force applying member 16 become equal.

[0033] Furthermore, the two first urging members 16 connected to the left support member 14A and the two first urging members 16 connected to the right support member 14B form a pair in the left-right direction. Thus, the urging force applied to the left support member 14A and the urging force applied to the right support member 14B become equal.

[0034] Figure 4 It is a perspective view showing a state where the support object W is arranged between the two cutout portions 28 .

[0035] By contracting the plurality of first force applying members 16, as Figure 4 As shown, the pair of support members 14 can move in a separation direction opposite to the approaching direction. The contraction of the plurality of first biasing members 16 can be easily achieved by using an actuator 22 described later.

[0036] An object W having a circumferential surface 32 and an axis 34 passing through the center of the circumferential surface 32 can be disposed between the two opposed cutouts 28 . Thus, the object W is sandwiched by the two cutouts 28 from both sides of the circumferential surface 32 .

[0037] Figure 5 yes Figure 2 VV cross-section diagram.

[0038] The plurality of bearings 18 are components provided in the plurality of elongated holes 28s of the cutout portion 28. The plurality of bearings 18 are provided one by one in each of the elongated holes 28s. In addition, each of the bearings 18 has a rolling element 36 and a support element 38.

[0039] The rolling element 36 is, for example, a radial bearing and has an axis 34 ( Figure 6 ) is a component parallel to the rotation axis 39.

[0040] The support body 38 is a member that rotatably supports the rolling element 36. The support body 38 is provided above the long hole 28s and has a shorter side (in Figure 5 Therefore, the support body 38 will not fall downward through the long hole 28s. The support body 38 and the support member 14 are not fixed to each other. Thus, the support body 38 can slide relative to the support member 14.

[0041] The support body 38 has an extension portion 38a inserted through the long hole 28s and a flange portion 38b that limits the vertical movable width of the support body 38. The flange portion 38b is provided at the lower end side of the extension portion 38a, and contacts the lower surface of the support member 14 from below to limit the upward movement of the sliding support body 38.

[0042] The rolling element 36 is rotatably connected to the lower end of the extension portion 38a. In this regard, for example, when the rolling element 36 is a radial bearing, the inner ring of the radial bearing can be connected to the extension portion 38a. In this way, the outer ring of the radial bearing can be allowed to rotate, and the radial bearing can be supported by the support body 38.

[0043] In addition, the structure of the bearing portion 18 is not limited to the above. For example, the rolling element 36 may be a so-called roller (cylindrical roller, barrel roller, etc.). In this case, the roller may be rotatable by providing a bearing structure that rotatably supports the roller on the extension portion 38a, or the extension portion 38a may be fixed relative to the roller and a bearing structure that rotatably supports the extension portion 38a may be provided on the support body 38.

[0044] The plurality of second force applying members 20 are members for applying force to the plurality of bearing portions 18 toward the support object W disposed between the two cutout portions 28. The plurality of second force applying members 20 are disposed one each on the extension line of the respective long side direction of the plurality of long holes 28s disposed radially on the support member 14, and are extended and retracted along the long side direction. Thus, in coordination with the extension and retraction of the second force applying members 20, the bearing portion 18 slides along the long side direction of the long hole 28s.

[0045] The biasing force of the second biasing members 20 is set to be stronger than the force applied by the first biasing members 16 to the pair of support members 14. In the present embodiment, the second biasing members 20 are compression coil springs, but like the first biasing members 16, they are not limited to compression coil springs.

[0046] Each bearing portion 18 is connected to a second urging member 20. When the bearing portion 18 is not subjected to a compressive force by the second urging member 20 connected to the bearing portion 18, a portion of the rolling element 36 is kept exposed from the cutout portion 28 ( Figure 3 ).

[0047] The actuator 22 is provided on the base portion 12, and moves the pair of support members 14 in a direction approaching each other, thereby causing the pair of support members 14 to clamp the support object W. In the present embodiment, the actuator 22 is a pair of cylinders that are driven to apply a linear force in the left and right directions to the pair of support members 14. One cylinder in the pair is connected to the left support member 14A, and the other cylinder is connected to the right support member 14B.

[0048] The actuator 22 is not limited to a pair of air cylinders as long as it moves the pair of support members 14 toward each other. For example, the actuator 22 may be configured using a hydraulic cylinder, a ball screw mechanism, or an electric motor.

[0049] The control unit 24 switches between clamping the object W by the pair of support members 14 and clamping the object W by the plurality of bearings 18 by controlling the actuator 22. This switching will be described later. In the present embodiment, the control unit 24 is a controller of the pair of air cylinders.

[0050] In the present embodiment, the state in which the movement of the pair of support members 14 is controlled by the actuator 22 is referred to as the "on state" of the actuator 22. In addition, the state in which the movement is not controlled by the actuator 22 is referred to as the "off state" of the actuator 22. By providing the support device 10 with the control unit 24, the switching between the on state and the off state can be easily realized.

[0051] The above is an overview of the configuration of the support device 10 of the present embodiment. Next, switching between clamping of the support object W by the pair of support members 14 and clamping of the support object W by the plurality of bearings 18 in the support device 10 will be described.

[0052] First, the clamping of the support object W by the pair of support members 14 by the support device 10 of this embodiment will be described. Figure 4 The state of the actuator 22 is turned on to make the pair of support members 14 approach each other to achieve the clamping.

[0053] Figure 6 This is a first diagram for explaining the clamping of the support object W by the pair of support members 14 .

[0054] When the pair of support members 14 are moved in a direction approaching each other, first, the rolling element 36 contacts the support object W. Here, the actuator 22 moves the pair of support members 14 in the approaching direction with a force greater than the force of the plurality of second force applying members 20 of the left support member 14A and the force of the plurality of second force applying members 20 of the right support member 14B. Thus, along with the movement, a pressing force is applied from the support object W to the rolling element 36. At this time, the plurality of second force applying members 20 absorb the pressing force by contracting themselves.

[0055] Figure 7 This is a second diagram for explaining the clamping of the support object W by the pair of support members 14 .

[0056] The plurality of second biasing members 20 are contracted, and the plurality of bearings 18 slide away from the supported object W. If the pair of support members 14 are further moved in the approaching direction by the actuator 22, the plurality of bearings 18 slide away from the supported object W. Figure 7 As shown, each of the notch portions 28 of the pair of support members 14 is in contact with the support object W. The pair of support members 14 clamps the support object W by maintaining this state.

[0057] exist Figure 7 In the clamping state, the supported object W is firmly clamped from both sides of the circumferential surface 32 by the arc-shaped cutouts 28 respectively provided on the pair of supporting members 14, thereby preventing the supported object W from rotating relative to the supporting device 10. Therefore, when the supported object W is not intended to rotate, Figure 7 The clamping state is appropriate.

[0058] In this case, if the surface of the cutout portion 28 has the concavoconvex shape 30 , the concavoconvex shape functions as an anti-slip portion for the supported object W. Thus, the supported object W can be better clamped by the pair of support members 14 so as not to rotate.

[0059] Figure 8 This is a first diagram for explaining the clamping of the support object W by the plurality of bearing portions 18 .

[0060] Next, the clamping of the support object W by the plurality of bearing portions 18 will be described. This clamping can be achieved by turning the actuator 22 into an off state. That is, when the actuator 22 is turned into an off state, the pair of support members 14 are urged toward each other by the plurality of first urging members 16. As a result, first, the rolling elements 36 of the plurality of bearing portions 18 provided on the pair of support members 14 come into contact with the support object W, similarly to when the pair of support members 14 are moved by the actuator 22.

[0061] Here, as described above, the force of the plurality of second urging members 20 pushing the plurality of bearings 18 toward the support object W is stronger than the force applied by the plurality of first urging members 16 to the pair of support members 14. Therefore, when the actuator 22 is in the disconnected state, the plurality of bearings 18 will not be as Figure 7 The bearings 18 are pressed into the bearings 18 as shown in the figure, and the rolling elements 36 provided therein can clamp the object W to be supported. In this way, the object W to be supported can be clamped by the plurality of bearing portions 18.

[0062] Fig. 9 This is a second diagram for explaining how the support object W is clamped by the plurality of bearings 18 .

[0063] exist Figure 8 In the state of , when the supported object W rotates around the axis 34, the rolling element 36 also rotates around its own rotation axis. Figure 8 In the state, the supporting device 10 as a whole does not rotate, and can rotatably support the supporting object W.

[0064] Thus, for example Fig. 9 As shown, the screw member as the support object W can be rotatably supported by the support device 10 while the work of fastening to other members W' can be easily performed. At this time, if the base portion 12 is provided with a hole 26, the support object W can be easily reached from the base portion 12 side through the hole 26 using a tool T for screw fastening. Since the support device 10 does not rotate during the fastening work, the support device 10 can be easily fixed at one position, and the fastening work can be performed with good workability even in a place with limited space.

[0065] Thus, according to the present embodiment, a support device 10 is provided that can rotatably support a support object W without rotating itself. In addition, according to the configuration of the support device 10 of the present embodiment, the support object W can also be supported in a non-rotating manner. Furthermore, according to the configuration of the support device 10 of the present embodiment, the case of rotatably supporting the support object W and the case of non-rotatably supporting the support object W can be arbitrarily and flexibly utilized.

[0066] [Modifications]

[0067] The above embodiment is described as an example of the present invention. Various changes or improvements can be made to the above embodiment. In addition, it is clear from the description of the claims that the form to which such changes or improvements are added can be included in the technical scope of the present invention.

[0068] (Variant 1)

[0069] Hereinafter, the support device 10 according to the modification 1 will be described. However, description of the elements having the same names and the same reference numerals as those described in the embodiment will be appropriately omitted.

[0070] Fig.10 It is a diagram for explaining the structure of the support device 10 according to the first modification. Fig.11 yes Fig.10 XI-XI section view.

[0071] The structure of the bearing 18 is not limited to the embodiment. For example, the bearing 18 may include a housing 40, rolling elements 42, and a ball sliding portion 44. Hereinafter, for convenience, the bearing 18 of this modification is also described as a bearing 18'.

[0072] The housing portion 40 is provided to house the rolling element 42 and has an opening 46 facing the supported object W sandwiched between the pair of supporting members 14. The housing portion 40 may be a plurality of cavities provided in the pair of supporting members 14.

[0073] In the housing portion 40 , the inner surface that contacts the accommodated rolling element 42 is preferably smooth so that the rolling element 42 can appropriately roll as described below.

[0074] The rolling element 42 of this modification is spherical and has a diameter larger than the opening 46 (R 42 >R 46 ). The rolling element 42 is accommodated in the accommodation portion 40 as described above. In this modification, the rolling element 42 contains metal as its material.

[0075] The ball sliding portion 44 is a member connected to the second urging member 20 in the housing portion 40, and is a member that rollably supports the rolling element 42 and urges the rolling element 42 toward the opening 46. In this modification, the ball sliding portion 44 has a disk shape.

[0076] In addition, in the ball sliding portion 44 , it is preferable that the surface that contacts the rolling element 42 is smooth as the surface inside the housing portion 40 .

[0077] The plurality of bearings 18' can rotatably clamp the supported object W. That is, in the configuration of this modified example, the rolling element 42 is pressed toward the opening 46 by the second biasing member 20 via the ball sliding portion 44, and a portion thereof is exposed to the outside of the housing portion 40 from the opening 46. As a result, each rolling element 42 of the plurality of bearings 18' contacts the supported object W.

[0078] Here, when the actuator 22 is in the OFF state, the object W is sandwiched by the plurality of rolling elements 42 biased by the plurality of second biasing members 20 , rather than by the pair of support members 14 biased by the plurality of first biasing members 16 , for the same reason as in the embodiment.

[0079] The rolling element 42 itself can roll, and thus allows the supported object W in contact therewith to rotate. Therefore, in this modification, the supporting device 10 can also rotatably support the supported object W without rotating itself.

[0080] [Inventions from Embodiments]

[0081] The invention that can be grasped from the above-mentioned embodiment and modified examples is described below.

[0082] A support device 10 for supporting a support object W having a circumferential surface 32, comprising: a base portion 12; a pair of support members 14, which are slidably arranged relative to the base portion 12 and are provided with arc-shaped cutout portions 28 for clamping the circumferential surface 32 from both sides; a plurality of first force-applying members 16, which apply force to the pair of support members 14 in a direction of approaching each other; a plurality of bearing portions 18, which are arranged along the cutout portions 28 of each of the pair of support members 14, and are used to allow the support object W to move with the support pair The supporting object W is clamped in a manner rotating around the axis 34 of the object W; and a plurality of second force-applying members 20, which apply force to the plurality of bearing portions 18 toward the supporting object W in order to enable the plurality of bearing portions 18 to clamp the supporting object W, wherein the force applied by the plurality of first force-applying members 16 and the force applied by the plurality of second force-applying members 20 are set so that the plurality of bearing portions 18 can clamp the supporting object W with a force stronger than the force applied by the plurality of first force-applying members 16 to the pair of supporting members 14.

[0083] Thus, there is provided the support device 10 which can rotatably support the support object W without rotating itself.

[0084] The base portion 12 may be provided with a hole 26 that penetrates the base portion 12 in the thickness direction and faces the supported object W when the supported object W is clamped by the pair of supporting members 14 or the plurality of bearing portions 18. Thus, visibility of the supported object W can be ensured and the supported object W can be easily approached by a tool T or the like.

[0085] There may be further an actuator 22 provided on the base portion 12, which moves the pair of support members 14 in the approaching direction to each other, thereby causing the pair of support members 14 to clamp the support object W. Thus, by turning on the actuator 22, the support object W can be supported in a manner that does not rotate.

[0086] The control unit 24 may further be provided, and the control unit 24 switches the clamping of the support object W by the pair of support members 14 and the clamping of the support object W by the plurality of bearings 18 by controlling the actuator 22. Thus, it is possible to easily switch between a state in which the support object W is rotatably supported and a state in which the support object W is non-rotatably supported.

[0087] The surface of the cutout portion 28 of the support member 14 may be formed with a concavo-convex shape 30. Thus, since the concavo-convex shape 30 functions as an anti-slip portion, it is possible to better support the object W so that it does not rotate.

[0088] The plurality of bearings 18 may include a bearing 18 including a rolling element 36 and a support element 38, the rolling element 36 having a rotation axis 39 parallel to the axis 34 of the supported object W, the support element 38 being connected to one of the plurality of second force applying members 20 and rotatably supporting the rolling element 36. Thus, the rolling element 36 having the rotation axis 39 parallel to the axis 34 can rotatably clamp the supported object W.

[0089] Each of the plurality of bearing portions 18 may include a bearing portion 18 having a receiving portion 40, a spherical rolling element 42, and a spherical sliding portion 44, wherein the receiving portion 40 is provided with an opening 46 facing the supported object W clamped by the pair of supporting members 14, and the spherical rolling element 42 is received in the receiving portion 40 and has a diameter R larger than that of the opening 46. 42The ball sliding portion 44 is connected to one of the plurality of second urging members 20, rollably supports the rolling element 42, and urges the rolling element 42 toward the opening 46. Thus, the rolling element 42 rolling in the storage portion 40 can rotatably clamp the supported object W.

Claims

1. A support device (10) for supporting an object (W) having a circumferential surface (32), characterized in that: have: A base portion (12); a pair of supporting members (14) which are slidably arranged relative to the base portion and are provided with arc-shaped cutout portions (28) for clamping the circumferential surface from both sides; a plurality of first force applying members (16) for applying force to the pair of supporting members in a direction of approaching each other; a plurality of bearing portions (18) provided along the cutout portions of each of the pair of supporting members and used to clamp the supported object in a manner such that the supported object can rotate around the axis (34) of the supported object; as well as A plurality of second force applying members (20) for applying force to the plurality of bearing parts toward the supported object so that the plurality of bearing parts clamp the supported object. The urging forces of the plurality of first urging members and the urging forces of the plurality of second urging members are set so that the plurality of bearing portions can clamp the support object with a force stronger than a force applied by the plurality of first urging members to the pair of support members.

2. The support device according to claim 1, characterized in that The base portion is provided with a hole (26) which penetrates the base portion in the thickness direction and faces the supported object when the supported object is clamped by the pair of supporting members or the plurality of bearing portions.

3. The supporting device according to claim 1 or 2, characterized in that: An actuator (22) is also provided, the actuator (22) being arranged on the base portion and causing the pair of supporting members to clamp the supported object by moving the pair of supporting members in the approaching directions relative to each other.

4. The support device according to claim 3, characterized in that A control unit (24) is further provided, which switches between the clamping of the supported object by the pair of supporting members and the clamping of the supported object by the plurality of bearings by controlling the actuator.

5. The supporting device according to claim 1 or 2, characterized in that: A concavo-convex shape (30) is formed on the surface of the cutout portion of the support member.

6. The supporting device according to claim 1 or 2, characterized in that: The plurality of bearing parts include a bearing part having the following components: a rolling element (36) having a rotation axis (39) parallel to the axis of the supported object; and A support body (38) is connected to one of the plurality of second force applying members and rotatably supports the rolling body.

7. The supporting device according to claim 1 or 2, characterized in that: Each of the plurality of bearing parts includes a bearing part having the following components: a storage portion (40) provided with an opening (46) facing the supported object clamped by the pair of supporting members; and The spherical rolling element (42) is received in the receiving portion and has a diameter (R 42 ); as well as A ball sliding portion (44) is connected to one of the plurality of second urging members, supports the rolling element in a rollable manner, and urges the rolling element toward the opening.

Images