Universal joint, connecting rod device, and pedal device for musical instruments

Abstract

A universal joint includes a pair of yokes connected to two rotating members, a cross connected to the pair of yokes so as to be rotatable, and a bearing provided at a connection portion of the pair of yokes and the cross to support the cross so as to be rotatable. The cross is configured to be arranged in a space formed by inner surfaces of the pair of yokes and to fix an outer ring of the bearing to the cross.

Description

Technical Field

[0001] This disclosure relates to universal joints, connecting rod devices, and pedal devices for musical instruments. Background Technology

[0002] A method for playing a bass drum using left and right pedal devices operated by both feet is known. For example, by operating a pedal device with the left foot, the rotation axis of another pedal device located away from the first pedal device rotates. Furthermore, a beater fixed to the rotation axis of the other pedal device rotates, thereby striking the bass drum. The left and right pedal devices are used with their rotation axes connected to each other via a connecting rod. In this case, the positions of the left and right pedal devices often vary depending on the user's body shape or preference. Therefore, to flexibly correspond to the positions of the left and right pedal devices, a universal joint is used that allows for an angular connection between the connecting rod and the rotation axis.

[0003] The universal joint includes: a pair of forks connected to two rotating components respectively; a cross fork rotatably connected to the two forks; and multiple bearings for connecting the two forks and the cross fork. The cross fork is rotatably connected to the two forks about two orthogonal axes via the bearings. The universal joint is configured to change the connection angle between the connecting rod and the rotating shaft, and to transmit rotation about those axes between the connecting rod and the rotating shaft.

[0004] As a universal joint suitable for use with drum pedals, etc., a universal joint with the following structure is proposed, for example. Universal joints disclosed in U.S. Patent No. 7,633,000, U.S. Patent No. 8,556,735, and U.S. Patent No. 6,878,068 have a pair of forks, an annular cross fork disposed on the outside of the two forks, and four bearings. Universal joints disclosed in U.S. Patent No. 8,110,731 or U.S. Patent No. 7,641,560 have a pair of forks, a block-shaped cross fork disposed on the inside of the two forks, and four bearings.

[0005] The cross fork in U.S. Patent No. 7,633,000 is a single component. The cross fork in U.S. Patent No. 8,556,735 is constructed by assembling two separate parts. Both documents have four radially penetrating holes formed at equal intervals in the cross fork. Bearings and shafts are respectively disposed in the four holes of the cross fork. The shaft is pressed into both the inner wheel of the bearing and the hole at the tip of the fork. The outer wheel of the bearing is fixed to the hole in the cross fork. The cross fork in U.S. Patent No. 6,878,068 consists of a cross fork body and four cover members assembled to the cross fork body. The cross fork in this document also has four radially penetrating holes formed at equal intervals. Bearings and protrusions at the tip of the fork are respectively disposed in the four holes of the cross fork. The inner wheel of the bearing is fixed to the protrusion at the tip of the fork. The outer wheel of the bearing is fixed to the hole in the cross fork.

[0006] The cross fork in U.S. Patent No. 8,110,731 has holes for mounting bearings on each of its four sides that connect to the fork. The fork has threaded holes corresponding to the holes in the cross fork. The inner wheel of the bearing is fixed to the tip of a threaded pin that engages with the threaded hole in the fork. The outer wheel of the bearing is fixed to the hole in the cross fork. The cross fork in U.S. Patent No. 7,641,560 also has threaded holes on each of its four sides that connect to the fork. The fork has threaded holes corresponding to the threaded holes in the cross fork. The inner wheel of the bearing is fixed to the side of the cross fork by screws and annular washers. The outer wheel of the bearing is fixed to the threaded hole in the fork. Summary of the Invention

[0007] The cross forks in U.S. Patent Nos. 7633000, 8556735, and 6878068 are all annular bodies with an outer diameter larger than the segmented forks. This means that because these cross forks are larger in size and weight, the torque generated when rotational force is transmitted between the two segments is tends to be greater. Therefore, in the dual-pedal system with the universal joints described in U.S. Patent Nos. 7633000, 8556735, and 6878068, when playing the bass drum, the feel of pressing the pedal with the left foot, or the return motion of the pressed left pedal, is prone to differ from the feel of operating the pedal with the right foot. Consequently, when playing the bass drum using the left and right pedal devices, a sense of dissonance is produced, resulting in an unpleasant operating experience. Furthermore, in the cross forks described in U.S. Patent No. 7,633,000 and U.S. Patent No. 8,556,735, the four holes formed in a single component or two separate parts for fixing the bearing are subject to strict requirements for positional and dimensional accuracy. This is because when fixing the bearing using all four holes simultaneously, if even one hole has a larger diameter or is misaligned, the bearing positioned within the hole cannot be securely fixed. Additionally, in the cross fork described in U.S. Patent No. 6,878,068, the structure is complex due to the large number of components constituting the cross fork.

[0008] In the universal joint described in U.S. Patent No. 8,110,731, when the threaded pin is tightened, axial loads are easily applied to the inner wheel of the bearing. Therefore, depending on the tightening of the threaded pin, the bearing may lock. In the universal joint described in U.S. Patent No. 7,641,560, the inner and outer wheels of the bearing are intentionally clamped to eliminate wobble. However, depending on the tightness of the screws or the dimensional accuracy of the components, the bearing may still lock due to axial loads. Furthermore, in the universal joint described in U.S. Patent No. 7,641,560, because the outer wheel of the bearing is fixed to the fork, the torque is more likely to increase compared to the universal joint described in U.S. Patent No. 8,110,731, where the outer wheel of the bearing is fixed to the cross fork.

[0009] The problem that the invention aims to solve

[0010] The purpose of this disclosure is to provide universal joints, connecting rod devices, and musical instrument pedal devices that can reduce torque and ease manufacturing burden.

[0011] Solution for solving the problem

[0012] According to one aspect of this disclosure, a universal joint is provided. The universal joint includes: a pair of forks connected to two rotating members respectively; a cross fork rotatably connected to the pair of forks; and a bearing disposed at the connection between the pair of forks and the cross fork, supporting the cross fork for rotation. The cross fork is configured to be disposed within a space formed by the inner surfaces of the pair of forks and to fix the outer wheel of the bearing to the cross fork.

[0013] According to other embodiments of this disclosure, a universal joint is provided. The universal joint includes: a pair of forks connected to two rotating members respectively, each fork having an insertion hole for inserting the rotating members; and a cross fork rotatably connected to the pair of forks. At least one of the pair of forks includes: a retaining member for securing the rotating member to the insertion hole; and a pressing member disposed in the insertion hole, which, by being pressed by the retaining member, presses and secures the rotating member to the wall surface of the insertion hole. The pressing member is configured to contact the surface of the rotating member.

[0014] According to another aspect of this disclosure, a connecting rod device is provided. The connecting rod device is configured to connect a first device generating a first rotation and a second device generating a second rotation, and to transmit the first rotation to the second device. The connecting rod device includes: a universal joint connected to at least one of the first device and the second device; and a connecting rod connected to the first device and the second device via the universal joint. The universal joint includes: a pair of forks connected to two rotating members respectively; a cross fork rotatably connected to the pair of forks; and a bearing disposed at the connection between the pair of forks and the cross fork, supporting the cross fork for rotation. The cross fork is configured to be disposed in a space formed by the inner surfaces of the pair of forks, and to fix the outer wheel of the bearing to the cross fork.

[0015] According to another aspect of this disclosure, a pedal device for a musical instrument is provided. The pedal device comprises a plurality of pedals for use in a configuration where the rotational axes of each pedal are connected to each other via a universal joint. The universal joint comprises: a pair of forks connected to two rotating members respectively; a cross fork rotatably connected to the pair of forks; and a bearing disposed at the connection between the pair of forks and the cross fork, supporting the cross fork for rotation. The cross fork is configured to be disposed within a space formed by the inner surfaces of the pair of forks, and to fix the outer wheel of the bearing to the cross fork. Attached Figure Description

[0016] Figure 1 This is a perspective view of a double pedal, which embodies the pedal device for musical instruments disclosed herein.

[0017] Figure 2 It is set in Figure 1 A perspective view of a double-pedal connecting rod device with a universal joint of the present disclosure.

[0018] Figure 3 yes Figure 1 A 3D view of a universal joint.

[0019] Figure 4 yes Figure 1 An exploded perspective view of the universal joint.

[0020] Figure 5 yes Figure 1 A three-dimensional view of the first fork of the universal joint.

[0021] Figure 6 Viewed from the axis of rotation Figure 1 Front view of the universal joint.

[0022] Figure 7This shows the state in which the rotating shaft is tilted about its axis. Figure 1 Front view of the universal joint.

[0023] Figure 8 This illustrates the state in which the tilt of the rotating shaft about its axis is corrected by pressing it down with the pressing member. Figure 1 Front view of the universal joint.

[0024] Figure 9 It is along Figure 6 A sectional view along line 9-9.

[0025] Figure 10 It is along Figure 6 A sectional view along line 10-10. Detailed Implementation

[0026] The following is for reference Figures 1-10 An embodiment that embodies the universal joints 30 and 40, the connecting rod device 22, and the double pedal 20 as a pedal device for musical instruments will be described.

[0027] like Figure 1 As shown, the dual-pedal 20 includes a pair of pedal devices 21L and 21R operated by the left and right feet, and a connecting rod device 22 connecting the pedal devices 21L and 21R. The left pedal device 21L, serving as the first device, includes a left pedal 23L and a rotation shaft 24L, which rotates when the left pedal 23L is pressed. The right pedal device 21R, serving as the second device, includes a right pedal 23R, a first rotation shaft 24R1, which rotates when the right pedal 23R is pressed, and a second rotation shaft 24R2, which is a rotation member. The second rotation shaft 24R2 is connected to the rotation shaft 24L of the left pedal device 21L via the connecting rod device 22. The dual-pedal 20 is used with the rotation shaft 24L of the left pedal device 21L and the second rotation shaft 24R2 of the right pedal device 21R connected.

[0028] The first and second rotation axes 24R1 and 24R2 are respectively equipped with percussion devices 26 and 27 for striking the bass drum BD. In the dual pedal 20, when the right pedal 23R is operated with the right foot, the percussion device 26 rotates together with the first rotation axis 24R1 of the right pedal device 21R, and the bass drum BD is struck by the percussion device 26. On the other hand, when the left pedal 23L is operated with the left foot, the rotation axis 24L of the left pedal device 21L rotates, and this rotation is transmitted to the second rotation axis 24R2 of the right pedal device 21R via the connecting rod device 22. Furthermore, through the rotation of the second rotation axis 24R2, the percussion device 27 rotates together with the second rotation axis 24R2, and the bass drum BD is struck by the percussion device 27. That is to say, the connecting rod device 22 is used to transmit the rotation of the rotation axis 24L caused by stepping on the left pedal 23L to the second rotation axis 24R2 of the right pedal device 21R.

[0029] like Figure 1 and Figure 2 As shown, the connecting rod device 22 includes a left universal joint 30 and a right universal joint 40. The left universal joint 30 is connected to the rotation shaft 24L of the left pedal device 21L. The right universal joint 40 is connected to the second rotation shaft 24R2 of the right pedal device 21R. Furthermore, the connecting rod device 22 includes a rod assembly 50, which serves as a rotating member connecting the left and right universal joints 30 and 40. The rod assembly 50 is constructed by assembling multiple connecting rods and is configured to allow adjustment of the overall length of the rod assembly 50.

[0030] The rod assembly 50 includes a first connecting rod 51, which serves as a rotating member connected to the universal joint 30 on the left, and a second connecting rod 52, which serves as a rotating member connected to the universal joint 40 on the right. The second connecting rod 52 has an upper surface 52a that is wider than the other surfaces, and its cross-section is hexagonal. The first connecting rod 51 is cylindrical and configured to accommodate the second connecting rod 52. The second connecting rod 52 is slidably disposed within the first connecting rod 51 in the axial direction of the first connecting rod 51.

[0031] Additionally, the rod assembly 50 includes an adjuster 54 for adjusting the overall length of the rod assembly 50. The adjuster 54 has a bolt 55 for securing the second connecting rod 52 within the first connecting rod 51. The adjuster 54 is configured to press a pressure plate 57 against the upper surface 52a of the second connecting rod 52 by tightening the bolt 55. In other words, by operating the bolt 55, the position of the second connecting rod 52 relative to the first connecting rod 51 is changed to adjust the overall length of the rod assembly 50, or the adjusted length is fixed.

[0032] Additionally, the rod assembly 50 includes a memory lock 58, which is used to pre-store the overall length of the rod assembly 50. For example, sometimes the state during transport when the second connecting rod 52 is pulled out from the first connecting rod 51 is set to the state when the second connecting rod 52 is inserted into the first connecting rod 51. In this case, by pre-assembling the memory lock 58 onto the second connecting rod 52, the rod assembly 50 can be easily restored to its original length before transport.

[0033] The memory lock 58 is a cylindrical shape with a flat upper surface and is fitted to the second connecting rod 52. A bolt 56 is threaded onto the upper surface of the memory lock 58. The memory lock 58 is configured such that the tip of the bolt 56 is directly pressed against the upper surface 52a by tightening the bolt 56. In other words, by operating the bolt 56, the position of the memory lock 58 relative to the second connecting rod 52 can be changed, or the position of the memory lock 58 can be fixed.

[0034] Next, refer to Figures 3-8 The structure of universal joints 30 and 40 will be described. Detailed descriptions of the parts in the left universal joint 30 that are identical to those in the right universal joint 40 are omitted.

[0035] like Figure 3 and Figure 4 As shown, the universal joint 40 includes a first fork 41 connected to the second rotation shaft 24R2 of the right-side pedal assembly 21R, and a second fork 42 connected to the second connecting rod 52 of the rod assembly 50. The first fork 41 rotates together with the second rotation shaft 24R2, and the second fork 42 rotates together with the second connecting rod 52. Additionally, the universal joint 40 includes a cross fork 43 rotatably connected to the first and second forks 41 and 42, and four bearings for connecting the first and second forks 41 and 42 and the cross fork 43. A pair of first bearings 44 are located at the connection between the first fork 41 and the cross fork 43, and a pair of second bearings 45 are located at the connection between the second fork 42 and the cross fork 43. The pair of first bearings 44 share an axis C1, and support the cross fork 43 at two points along the axis C1 for rotatability. Similarly, a pair of second bearings 45 share an axis C2, and the cross 43 is supported at two points on the axis C2 so that it can rotate.

[0036] The cross fork 43 is rotatably connected to the first and second forks 41 and 42 respectively via four bearings about two orthogonal axes C1 and C2. By connecting the cross fork 43 to the first and second forks 41 and 42 as described above, the universal joint 40 is configured to change the connection angle between the second connecting rod 52 and the second rotating shaft 24R2. Furthermore, the universal joint 40 is configured to transmit rotation about those axes between the second connecting rod 52 and the second rotating shaft 24R2.

[0037] Next, the structure of the first and second forks 41 and 42 will be described in detail. Detailed descriptions of the parts in the second fork 42 that are identical to those in the first fork 41 will be omitted.

[0038] like Figures 4-6 As shown, the first fork 41 includes a cylindrical fork body 41a connected to the second rotating shaft 24R2, and a pair of upper and lower arms 41b respectively fitted with the first bearing 44. An insertion hole 41c with a generally T-shaped cross-section is formed in the fork body 41a. The upper half of the insertion hole 41c has a rectangular cross-section. The lower half of the insertion hole 41c has a generally semi-circular cross-section.

[0039] A pressing member 46 with a roughly U-shaped cross-section and a flat, quadrangular prism-shaped positioning member 47 are housed in the upper part of the insertion hole 41c. The pressing member 46 consists of a bottom wall 46a and a pair of side walls 46b extending upward from both sides of the bottom wall 46a. A pressing portion 46d with a flat surface 46c protrudes from the outer surface of the bottom wall 46a. The pressing member 46 is positioned in the insertion hole 41c with the pressing portion 46d facing downward.

[0040] The positioning member 47 is disposed in the space between the two side walls 46b of the pressing member 46. A threaded hole 47a is formed in the center of the positioning member 47. A through hole 41d for a bolt 60, serving as a fixing member, is formed in the upper center of the fork body 41a. The bolt 60 is inserted into the through hole 41d and screwed into the threaded hole 47a of the positioning member 47. In this state, the tip of the bolt 60 abuts against the inner surface of the bottom wall 46a of the pressing member 46.

[0041] The second rotating shaft 24R2 has a flat upper surface 28 with a generally circular cross-section. The upper surface 28 of the second rotating shaft 24R2 is formed to correspond to the pressing portion 46d of the pressing member 46 housed in the insertion hole 41c of the fork body 41a. Therefore, by tightening the bolt 60, the bottom wall 46a of the pressing member 46 is pressed by the top end of the bolt 60, thereby pressing the upper surface 28 of the second rotating shaft 24R2 by the pressing portion 46d of the pressing member 46. Thus, the second rotating shaft 24R2 is fixed to the fork body 41a of the first fork 41 by pressing against the wall surface 41e of the insertion hole 41c.

[0042] In this configuration, the pressing member 46 presses against the second rotation axis 24R2 from above, with its flat surface 46c in contact with the upper surface 28. Specifically, the flat surface 46c of the pressing member 46 is the contact surface that contacts the second rotation axis 24R2, and has a first width W1. The pressing member 46 has rounded corner portions 46e at both ends of the flat surface 46c in the width direction. Furthermore, the upper surface 28 of the second rotation axis 24R2 is the contact surface that contacts the pressing member 46, and has a second width W2 that is larger than the first width W1. It should be noted that the first and second widths W1 and W2 are dimensions in directions orthogonal to the axes C3 and C4 of the bolt 60 and the second rotation axis 24R2, respectively, when the pressing member 46 is in contact with the second rotation axis 24R2.

[0043] like Figure 4 , Figure 5 , Figure 9 , Figure 10 As shown, arm 41b extends from the upper and lower parts of the first fork 41 on the side opposite to the opening of the insertion hole 41c of the fork body 41a. A fixing hole 41f is formed near the top of arm 41b, which is used to fix the first bearing 44 together with the annular bushing 49. The inner wheel 44a of the first bearing 44 and the bushing 49 are fixed in a state where they are sandwiched between the head of the fixing pin 48 and arm 41b by pressing the top of the fixing pin 48 into the fixing hole 41f. In this state, the fixing pin 48 fixes the inner wheel 44a of the first bearing 44 to the inner surface of arm 41b from the axial direction of the first bearing 44. The same method is used in the second fork 42, where the inner wheel 45a of the second bearing 45 and the bushing 49 are fixed in a state where they are sandwiched between the head of the fixing pin 48 and arm 42b. It should be noted that in this embodiment, the first bearing 44 and the second bearing 45 are ball bearings with multiple balls 44c and 45c arranged between the inner wheels 44a and 45a and the outer wheels 44b and 45b, respectively.

[0044] Next, the structure of the cross 43 will be explained in detail.

[0045] like Figure 3 and Figure 4As shown, the cross fork 43 is composed of multiple parts and is formed into a roughly hexahedral shape. The cross fork 43 is divided into a cross fork body 61 and a first cover 62 by first dividing surfaces 61a and 62a, and into a cross fork body 61 and a second cover 63 by second dividing surfaces 61b and 63a. The cross fork 43 is configured such that the outer wheels 44b and 45b of the four bearings 44 and 45 can be fixed to the cross fork 43 by assembling the cross fork body 61 and the first and second covers 62 and 63. The cross fork body 61 and the first and second covers 62 and 63 are assembled using bolts 70 as fixing members. In addition, the cross fork 43 is formed to be sized to fit within the space S formed by the inner surfaces of the first and second fork sections 41 and 42.

[0046] like Figure 4 , Figure 9 , Figure 10 As shown, the cross fork body 61 has a shape from which the portions of the generally hexahedral cross fork 43 to be assembled with the first and second covers 62, 63 and the four bearings 44, 45 are removed. Therefore, with the direction in which the first and second covers 62, 63 are assembled into the cross fork body 61 as a reference, the cross fork body 61 is U-shaped in side view and annular in front view.

[0047] A first receiving portion 61d1, which is a recess, is provided on the first dividing surface 61a of the cross fork body 61. A pair of outer wheels 44b of the first bearing 44 are arranged in the first receiving portion 61d1. The first receiving portion 61d1 is formed in the cross fork 43 as a part corresponding to the first cover 62 and the first bearing 44. The two inner end faces of the first receiving portion 61d1 are formed as arcs that partially conform to the outer peripheral surface of the outer wheels 44b of the first bearing 44.

[0048] A second receiving portion 61d2, which is a recess, is provided on the second dividing surface 61b of the cross fork body 61. A pair of outer wheels 45b of the second bearing 45 are arranged in the second receiving portion 61d2. The second receiving portion 61d2 is formed in the cross fork 43 as a part corresponding to the second cover 63 and the second bearing 45. The two inner end faces of the second receiving portion 61d2 are formed as arcs that partially conform to the outer peripheral surface of the outer wheels 45b of the second bearing 45.

[0049] A first through hole 62b through which a bolt 70 is inserted is formed in the center of the first cover 62, and a second through hole 62c having a larger diameter than the first through hole 62b. The second through hole 62c communicates with the first through hole 62b. A concave first abutment portion 62d is provided on the first dividing surface 62a of the first cover 62, and the outer wheels 44b of a pair of first bearings 44 abut against the first abutment portion 62d. The first abutment portion 62d is formed in an arc shape that partially conforms to the outer peripheral surface of the outer wheels 44b of the first bearings 44.

[0050] A threaded hole 63c is provided in the center of the second cover 63, and the tip of the bolt 70 is screwed into the threaded hole 63c. A concave second abutment portion 63d is provided on the second dividing surface 63a of the second cover 63, and the outer wheels 45b of a pair of second bearings 45 abut against the second abutment portion 63d. The second abutment portion 63d is formed in an arc shape that partially matches the outer peripheral surface of the outer wheels 45b of the second bearings 45. The second cover 63 is the same as the first cover 62, except that it has the threaded hole 63c instead of the first and second through holes 62b and 62c.

[0051] The cross fork body 61 and the first and second covers 62 and 63 are assembled on a straight line L1 orthogonal to the axis C1 of the first bearing 44 and the axis C2 of the second bearing 45. The first and second covers 62 and 63 are assembled to the cross fork body 61 in a position opposite to the cross fork body 61. Furthermore, the second cover 63 is assembled to the cross fork body 61 with an orientation 90 degrees different from the first cover 62. The cross fork body 61 and the first and second covers 62 and 63 are assembled from a direction orthogonal to axes C1 and C2 using bolts 70. The bolts 70 are configured to fix the first and second covers 62 and 63 to the cross fork body 61, and the axis C5 of the bolts 70 is aligned with the straight line L1.

[0052] Next, the function of the universal joints 30 and 40 mentioned above will be explained. First, refer to... Figure 4 , Figure 9 , Figure 10 The function of the assembly method for universal joints 30 and 40 is explained.

[0053] like Figure 4 , Figure 9 , Figure 10 As shown, on the inner surface of the first fork 41, the inner wheel 44a of the first bearing 44 is fixed from the axial direction of the first bearing 44 using a retaining pin 48 to assemble the first bearing 44. Similarly, on the inner surface of the second fork 42, the inner wheel 45a of the second bearing 45 is fixed from the axial direction of the second bearing 45 using a retaining pin 48 to assemble the second bearing 45.

[0054] Next, the first fork section 41, equipped with the first bearing 44, and the second fork section 42, equipped with the second bearing 45, are assembled to the cross fork body 61. First, the first bearing 44 of the first fork section 41 is inserted into the first storage portion 61d1 of the cross fork body 61. Then, the first cover 62 is inserted into the first storage portion 61d1 to cover the pair of first bearings 44 disposed within the first storage portion 61d1. Similarly, the second bearing 45 of the second fork section 42 is inserted into the second storage portion 61d2 of the cross fork body 61. Then, the second cover 63 is inserted into the second storage portion 61d2 to cover the pair of second bearings 45 disposed within the second storage portion 61d2.

[0055] Next, bolts 70 are used to secure the first and second covers 62 and 63 to the cross fork body 61. At this time, the bolts 70 tighten the head 70a in the threaded hole 63c of the second cover 63 until it abuts against the stepped portion 62e at the boundary between the first through hole 62b and the second through hole 62c. By securing the first and second covers 62 and 63 to the cross fork body 61 via the bolts 70, the outer wheel 44b of the first bearing 44 is clamped between the first cover 62 and the cross fork body 61. Thus, a pair of outer wheels 44b of the first bearing 44 are fixed on the first dividing surface 61a of the cross fork body 61 and the first dividing surface 62a of the first cover 62. Similarly, the outer wheel 45b of the second bearing 45 is clamped between the second cover 63 and the cross fork body 61. Thus, a pair of outer wheels 45b of the second bearing 45 are fixed on the second dividing surface 61b of the cross fork body 61 and the second dividing surface 63a of the second cover 63. In this way, the outer wheels 44b and 45b of the first and second bearings 44 and 45 are fixed to the cross fork 43, and the cross fork 43 is connected to the first and second fork sections 41 and 42 via the first and second bearings 44 and 45.

[0056] In this case, the direction in which the bolt 70 is tightened is orthogonal to the direction in which the retaining pin 48 is pressed in, i.e., the axes C1 and C2 of the first and second bearings 44 and 45. At this time, the load when the first and second covers 62 and 63 are assembled to the cross fork body 61 by the bolt 70 acts in a direction orthogonal to the axes C1 and C2 of the first and second bearings 44 and 45. Therefore, at the connection between the first and second fork sections 41 and 42 and the cross fork 43, the load caused by the tightening of the bolt 70 is unlikely to act in the same direction as the axes C1 and C2 of the first and second bearings 44 and 45. Therefore, when assembling the universal joints 30 and 40, the inner wheels 44a and 45a and the outer wheels 44b and 45b of the first and second bearings 44 and 45 are not easily locked together by the tightening of the bolt 70.

[0057] Furthermore, the cross fork 43 constituting the universal joints 30 and 40 is shaped to fit within the space S formed by the inner surfaces of the first and second forks 41 and 42. In other words, the cross fork 43 is shaped to fit within a space smaller than the outer dimensions of the first and second forks 41 and 42. Therefore, in the universal joints 30 and 40, the torque force generated when the rotational force is transmitted between the first and second forks 41 and 42 is reduced. Consequently, when playing the bass drum BD using the double pedals 20 with the universal joints 30 and 40, the following effect is achieved: the operating feel when pressing the left pedal 23L with the left foot, or when the pressed left pedal 23L returns to its original position, is less likely to deviate from the operating feel when operating the right pedal 23R with the right foot. Therefore, when playing the bass drum BD using the left and right pedal devices 21L and 21R, the sense of dissonance disappears, resulting in a good operating feel.

[0058] Next, refer to Figure 6 , Figure 7 , Figure 8 The function of the second rotating shaft 24R2 of the pedal device 21R connected to the universal joint 40 will be explained.

[0059] Figure 6 The diagram shows the state before the bolt 60 is tightened, where the second rotating shaft 24R2 is not tilted about the axis (C4). In this state, the flat surface 46c of the pressing member 46 and the upper surface 28 of the second rotating shaft 24R2 are approximately parallel. Therefore, by tightening the bolt 60, the flat surface 46c of the pressing member 46 and the upper surface 28 of the second rotating shaft 24R2 easily come into surface contact. Furthermore, as... Figure 8 As shown, the pressing member 46 presses down on the second rotating shaft 24R2 from above, thereby pressing the second rotating shaft 24R2 against the wall surface 41e of the insertion hole 41c. Figure 7 The diagram shows the state in which the second rotating shaft 24R2 is tilted about axis (C4) before the bolt 60 is tightened. In this state, the flat surface 46c of the pressing member 46 and the upper surface 28 of the second rotating shaft 24R2 are not parallel.

[0060] In this embodiment, the second width W2 of the upper surface 28 of the second rotating shaft 24R2 is greater than the first width W1 of the flat surface 46c of the pressing member 46. Furthermore, rounded corner portions 46e are provided at both ends of the flat surface 46c in the width direction. Therefore, when from... Figure 7 When bolt 60 is tightened as shown, the upper surface 28 of the second rotating shaft 24R2 is pressed against one corner 46e of the flat surface 46c. Consequently, the second rotating shaft 24R2 rotates about the axis (C4) towards... Figure 7 Rotate in the direction of the arrow shown until the flat surface 46c of the pressing member 46 and the upper surface 28 of the second rotation axis 24R2 come into contact. As a result, even from a state where the flat surface 46c of the pressing member 46 and the upper surface 28 of the second rotation axis 24R2 are not parallel, it can smoothly rotate towards... Figure 8 The state transition is shown in the case of the pressing member 46 and the second rotating shaft 24R2 in contact. That is, even if the second rotating shaft 24R2 is tilted about the axis (C4), the tilt of the second rotating shaft 24R2 about the axis (C4) can be corrected by pressing the second rotating shaft 24R2 with the pressing member 46.

[0061] Therefore, the following effects can be obtained according to this embodiment.

[0062] (1) The cross fork 43 is configured to fit within the space S formed by the inner surfaces of the first and second forks 41 and 42. In other words, the cross fork 43 is configured to fit within a space smaller than the outer dimensions of the first and second forks 41 and 42. Therefore, in the universal joints 30 and 40, the torque force generated when the rotational force is transmitted between the first and second forks 41 and 42 can be reduced.

[0063] (2) By assembling multiple components in directions orthogonal to the axes C1 and C2 of the first and second bearings 44 and 45, the outer wheels 44b and 45b of the first and second bearings 44 and 45 are fixed to the cross fork 43. At this time, the load caused by the assembly of the components acts in a direction orthogonal to the axes C1 and C2 of the first and second bearings 44 and 45. Therefore, at the connection between the first and second forks 41 and 42 and the cross fork 43, the aforementioned load is unlikely to act in the same direction as the axes C1 and C2 of the first and second bearings 44 and 45. Therefore, it becomes easier to assemble the universal joints 30 and 40 without locking the first and second bearings 44 and 45, which reduces the manufacturing burden.

[0064] (3) A concave first receiving portion 61d1 is provided on the first dividing surface 61a of the cross fork body 61, where an outer wheel 44b of the first bearing 44 is disposed. Additionally, a concave second receiving portion 61d2 is provided on the second dividing surface 61b of the cross fork body 61, where an outer wheel 45b of the second bearing 45 is disposed. According to this structure, the first and second bearings 44 and 45 can be disposed inside the cross fork 43 to assemble the universal joints 30 and 40. As a result, the shape near the connection between the first and second fork sections 41 and 42 and the cross fork 43 in the universal joints 30 and 40 becomes more compact, thus further reducing the torque force.

[0065] (4) The cross fork 43 is constructed by assembling the cross fork body 61 and the first and second covers 62 and 63. According to this structure, first and second bearings 44 and 45 are arranged in the first and second receiving portions 61d1 and 61d2 of the cross fork body 61. Furthermore, the first and second covers 62 and 63 are assembled to the cross fork body 61 in such a way that they cover the first and second bearings 44 and 45 within the first and second receiving portions 61d1 and 61d2. In this case, multiple components can be assembled to manufacture the cross fork 43, and the outer wheels 44b and 45b of the first and second bearings 44 and 45 can be fixed to the cross fork 43. Therefore, the workability of assembling the universal joints 30 and 40 is improved, and the manufacturing burden can be further reduced.

[0066] (5) A pair of first bearings 44 sharing a common axis C1 are fixed at two points on axis C1 via the first dividing surfaces 61a and 62a of the cross fork 43. Additionally, a pair of second bearings 45 sharing a common axis C2 are fixed at two points on axis C2 via the second dividing surfaces 61b and 63a of the cross fork 43. According to this structure, compared to the existing structure where four holes for fixing bearings are formed in the components constituting the cross fork 43, the number of bearings 44 that need to be aligned with the cross fork 43 is halved. Therefore, even if the dimensional accuracy of the components is lower than that of the existing cross fork structure described above, it becomes easier to press-fit and fix the outer wheel 44b of the bearing 44 to the cross fork 43. Thus, the manufacturing burden can be further reduced.

[0067] (6) The first cover 62 is inserted into the first storage section 61d1 to cover a pair of first bearings 44 disposed within the first storage section 61d1. Similarly, the second cover 63 is inserted into the second storage section 61d2 to cover a pair of second bearings 45 disposed within the second storage section 61d2. According to this structure, the first cover 62 for fixing the pair of first bearings 44 to the cross fork 43 is configured as a single component. Similarly, the second cover 63 for fixing the pair of second bearings 45 to the cross fork 43 is configured as a single component. Thus, compared with the structure in which each pair of bearings is fixed with a separate cover, the number of components is reduced and the structure is simplified. Therefore, the workability when assembling the universal joints 30 and 40 is further improved.

[0068] (7) The cross fork body 61, the first and second covers 62 and 63 are assembled on a straight line L1 orthogonal to the axis C1 of the first bearing 44 and the axis C2 of the second bearing 45. According to this structure, the center of gravity of the cross fork 43 can be set near the center of the space S formed by the inner surfaces of the first and second fork sections 41 and 42. Therefore, in the universal joints 30 and 40, because the center of gravity is set near the center of the universal joints 30 and 40, the torque force is further reduced.

[0069] (8) The first and second covers 62 and 63 are assembled to the cross fork body 61 in a position opposite to the cross fork body 61. This makes it easier to bring the center of gravity of the cross fork 43 closer to the center of the space S formed by the inner surfaces of the first and second forks 41 and 42.

[0070] (9) Bolt 70 is configured to fix the first and second covers 62, 63 to the cross fork body 61 and to align the axis C5 of bolt 70 with the straight line L1. According to this configuration, because bolt 70, the cross fork body 61, and covers 62, 63 are aligned on the same straight line, the center of gravity of the cross fork 43 can be brought closer to the center of the space S formed by the inner surfaces of the first and second fork sections 41, 42. Therefore, in the universal joints 30, 40, the center of gravity can be brought closer to the center of the universal joints 30, 40, thus further reducing the torque force.

[0071] (10) On the inner surface of the first fork 41, the inner wheel 44a of the first bearing 44 is fixed from the axial direction of the first bearing 44 using a retaining pin 48. Similarly, on the inner surface of the second fork 42, the inner wheel 45a of the second bearing 45 is also fixed from the axial direction of the second bearing 45 using a retaining pin 48. According to this structure, the direction in which the inner wheels 44a and 45a of the first and second bearings 44 and 45 are fixed on the inner surfaces of the first and second forks 41 and 42 is orthogonal to the direction in which the outer wheels 44b and 45b of the first and second bearings 44 and 45 are fixed on the cross fork 43. That is, the structure becomes such that when assembling the universal joints 30 and 40, it is difficult to apply a load in the same direction to the inner wheels 44a and 45a and the outer wheels 44b and 45b of the first and second bearings 44 and 45. Therefore, the inner wheels 44a, 45a and the outer wheels 44b, 45b of the first and second bearings 44, 45 do not become tight, making it easier to assemble the universal joints 30, 40 and further reducing the manufacturing burden.

[0072] (11) There is a method in which the top end of a fastener such as a screw or bolt is directly pressed against the rotating member to fix the rotating member to the wall surface of the insertion hole of the fork. In contrast, in this disclosure, the pressing member 46 is pressed from above by the bolt 60 to the second rotating shaft 24R2 in a state where the flat surface 46c is in contact with the upper surface 28. In this case, the force based on the axial direction of the bolt 60 can be transmitted to the second rotating shaft 24R2 in a state where the pressing member 46 pressed by the bolt 60 is in contact with the surface of the second rotating shaft 24R2. As a result, the second rotating shaft 24R2 can be press-fitted and fixed to the wall surface 41e of the insertion hole 41c. In this case, compared with the above-described conventional fixing method, the force based on the axial direction of the fastener can be transmitted to the rotating member over a wider area. As a result, the second rotating shaft 24R2 can be reliably fixed to the insertion hole 41c of the first fork 41.

[0073] (12) The upper surface 28 of the second rotating shaft 24R2 is a contact surface that contacts the surface of the pressing member 46, and has a second width W2 that is larger than the first width W1 of the flat surface 46c. According to this structure, when the pressing member 46 is pressed against the second rotating shaft 24R2 by a force based on the axial direction of the bolt 60, the corners 46e at both ends of the flat surface 46c in the width direction can press against the upper surface 28 of the second rotating shaft 24R2. Thus, even if the second rotating shaft 24R2 is tilted about the axis C4, it can smoothly transition to a state where the pressing member 46 and the surface of the second rotating shaft 24R2 are in contact. That is, even if the second rotating shaft 24R2 is tilted about the axis (C4), the tilt of the second rotating shaft 24R2 about the axis (C4) can be corrected by pressing the second rotating shaft 24R2 with the pressing member 46. Therefore, the workability is improved when the second rotating shaft 24R2 is fixed to the insertion hole 41c of the first fork 41 using bolt 60.

[0074] Furthermore, the pressing member 46 has rounded corner portions 46e at both ends of the flat surface 46c in the width direction. Due to this structure, the rounded corner portions 46e of the pressing member 46 facilitate contact between the corner portions 46e and the second rotating shaft 24R2. In other words, the corner portions 46e of the pressing member 46 are less likely to hook onto the upper surface 28 of the second rotating shaft 24R2. Therefore, pressing of the pressing member 46 onto the second rotating shaft 24R2 can be performed smoothly. Consequently, the transition to a state of surface contact between the pressing member 46 and the second rotating shaft 24R2 becomes easier.

[0075] The above-described embodiments can also be modified as follows.

[0076] In this embodiment, a pair of first bearings 44 are supported at two points on the axis C1 of the first bearings 44 by the cross fork 43, and a pair of second bearings 45 are supported at two points on the axis C2 of the second bearings 45 by the cross fork 43. Alternatively, for example, two bearings, one on each of the two orthogonal axes C1 and C2, can be fixed to the cross fork 43. That is, two bearings that do not have a common axis can also be fixed to the cross fork 43 to assemble the universal joints 30 and 40.

[0077] • In this embodiment, the cross fork 43 is approximately hexahedral in shape, but as long as it is a shape that can rotate within the space S formed by the inner surfaces of the first and second forks 41 and 42, it can also be any three-dimensional shape such as a sphere or a polyhedron.

[0078] In this embodiment, the first cover 62 can also be divided into two cover pieces, and the two cover pieces can be assembled onto the cross fork body 61 in such a way that each cover piece covers a pair of first bearings 44 disposed in the first storage portion 61d1. The second cover 63 can also be divided into two cover pieces and assembled onto the cross fork body 61 in the same way.

[0079] In this embodiment, bolts 70 are used to fix the first and second covers 62 and 63 to the cross fork body 61, but retaining pins can also be used. In this case, simply insert the retaining pin through the first insertion hole 62b and the second insertion hole 62c, and then press the tip of the retaining pin into the retaining hole of the second cover 63. Alternatively, magnets, adhesives, tapes, etc., can be used to fix the first and second covers 62 and 63 to the cross fork body 61 instead of bolts 70, retaining pins, or other fixing components.

[0080] In this embodiment, a retaining pin 48 is used to fix the inner wheels 44a and 45a of the first and second bearings 44 and 45 to the inner surfaces of the first and second forks 41 and 42, but bolts can also be used. In this case, the first and second bearings 44 and 45 can be fixed to the inner surfaces of the first and second forks 41 and 42 simply by forming threaded holes in the inner surfaces of the first and second forks 41 and 42 and tightening the bolts into the threaded holes.

[0081] • In this embodiment, the pressing part 46d may be omitted from the pressing member 46. In this case, since the bottom wall 46a of the pressing member 46 is in contact with the upper surface 28 of the second rotation axis 24R2, it is sufficient to form the bottom wall 46a as flat.

[0082] In this embodiment, the first bearing 44 and the second bearing 45 may be any rolling bearing, such as a roller bearing, which has rolling elements other than balls arranged between the inner and outer wheels.

[0083] In this embodiment, the corner 46e of the pressing member 46 may be formed in a rounded shape or in a C-shaped shape with an obtuse angle.

[0084] • In this embodiment, the musical instrument pedal device is specifically embodied as a double pedal 20 having a pair of pedal devices 21L and 21R operated by the left and right feet, but it can also be embodied as a drum system for playing a remote bass drum.

Claims

1. A universal joint comprising: a pair of yokes connected to two rotary members, respectively; a cross connected rotatably to the pair of yokes; and a bearing provided at a connection portion of the pair of yokes and the cross and supporting the cross so as to be rotatable, wherein the cross is configured to be arranged in a space formed by inner surfaces of the pair of yokes, wherein the cross is provided with a division surface that divides the cross into a plurality of members, wherein the plurality of members comprise: a cross body in which a housing portion in which the bearing is arranged is provided; and a cover that is assembled to the cross body in a manner of covering the bearing in the housing portion, and wherein the cross is configured to fix an outer race of the bearing to the division surface by sandwiching the outer race of the bearing with the cover and the cross body.

2. The universal joint according to claim 1, wherein the cross is configured by assembling the plurality of members from a direction orthogonal to an axis of the bearing.

3. The universal joint according to claim 1, wherein the bearing is one of a pair of bearings, and the cross is configured to fix outer races of the pair of bearings to the division surface.

4. The universal joint according to claim 1, wherein the bearing includes a pair of bearings, the pair of bearings share an axis, and are fixed to the division surface at two places on the axis.

5. The universal joint according to claim 4, wherein the pair of yokes are configured by a first yoke and a second yoke, the bearing is configured by a pair of first bearings provided at a connection portion of the first yoke and the cross, and a pair of second bearings provided at a connection portion of the second yoke and the cross, and the cover is configured to fix the pair of first bearings or the pair of second bearings to the cross.

6. The universal joint according to any one of claims 1 to 5, wherein the cross body and the cover are assembled in a state of being arranged on a straight line orthogonal to an axis of the bearing.

7. The universal joint according to claim 6, wherein the cover is assembled to the cross body at a position opposite to the cross body.

8. The universal joint according to claim 6, further comprising a fixing member that fixes the cover to the cross body and has an axis, wherein the fixing member is arranged in a manner of making the axis of the fixing member coincide with a straight line orthogonal to the axis of the bearing.

9. The universal joint according to any one of claims 1 to 5, wherein an inner race of the bearing is fixed to inner surfaces of the pair of yokes from a direction of an axis of the bearing. At least one of the pair of yokes comprises: a fixing member that fixes the rotary member to an insertion hole; and a pressing member that is provided to the insertion hole and is pressed by the fixing member to press-bond the rotary member to a wall surface of the insertion hole, wherein the pressing member is configured to be in surface contact with the rotary member.

11. The universal joint according to claim 10, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 10. The universal joint of any one of claims 1-5, wherein, ​ ​ ​ ​ ​ The pressing member has a contact surface that is in surface contact with the rotating member and has a first width, The rotating member has a contact surface that is in surface contact with the pressing member and has a second width that is greater than the first width.

12. The universal joint according to claim 11, wherein The pressing member has a rounded corner at each of both ends in the width direction of the contact surface.

13. A joint rod device configured to link a first device that generates a first rotation and a second device that generates a second rotation and to transmit the first rotation to the second device, The joint rod device includes: a universal joint connected to at least one of the first device and the second device; and a joint rod linked to the first device and the second device via the universal joint, The universal joint includes: a pair of yokes connected to two rotating members, respectively; a cross connected rotatably to the pair of yokes; and a bearing provided at a connection portion of the pair of yokes and the cross and supporting the cross so as to be rotatable, The cross is configured to be arranged in a space formed by inner surfaces of the pair of yokes, The cross is provided with a division surface that divides the cross into a plurality of components, the plurality of components including: a cross body provided with a housing portion in which the bearing is arranged; and a cover assembled to the cross body in a manner of covering the bearing in the housing portion, The cross is configured to fix an outer ring of the bearing to the division surface by the cover and the cross body sandwiching the outer ring of the bearing.

14. A musical instrument pedal device including a plurality of pedal devices used in a state in which rotating shafts of the respective pedal devices are linked to each other via a universal joint, in the musical instrument pedal device, The universal joint includes: a pair of yokes connected to two rotating members, respectively; a cross connected rotatably to the pair of yokes; and a bearing provided at a connection portion of the pair of yokes and the cross and supporting the cross so as to be rotatable, The cross is configured to be arranged in a space formed by inner surfaces of the pair of yokes, The cross is provided with a division surface that divides the cross into a plurality of components, the plurality of components including: a cross body provided with a housing portion in which the bearing is arranged; and a cover assembled to the cross body in a manner of covering the bearing in the housing portion, The cross is configured to fix an outer ring of the bearing to the division surface by the cover and the cross body sandwiching the outer ring of the bearing.

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