Centrifugal brakes

Abstract

To provide a novel centrifugal brake that can reliably and sufficiently switch braking torque. [Solution] The tips of multiple adjustment pieces 64 are connected to each other by a connecting ring 66, or a synthetic resin sliding piece 48 disposed on the outer circumferential surface of the weight body 46 is selectively brought into contact with the inner circumferential surface 8 of the housing 4 or the inner surface of the adjustment piece 64.

Description

Technical Field

[0001] The present invention relates to a centrifugal brake, particularly a centrifugal brake capable of gradually adjusting the magnitude of the braking torque applied to a rotating body according to required operations.

Background Art

[0002] Blinds may be arranged near a window indoors for purposes such as avoiding solar radiation. The blind has a plurality of slats arranged vertically and extending horizontally. The plurality of slats are each connected vertically by a lifting cord (sometimes referred to as an operating cord). The blind further includes a winding mechanism disposed above the slat located at the uppermost end and a bottom rail (sometimes referred to as a bottom pipe or a weight bar) disposed below the slat located at the lowermost end. One end of the lifting cord is connected to the winding mechanism and the other end is connected to the bottom rail, respectively. In such a blind, by operating the winding mechanism to wind up the lifting cord, the bottom rail rises, and by operating an appropriate locking mechanism provided in the winding mechanism, the bottom rail is held at an arbitrary position where it has risen. Then, when the operation of the locking mechanism is released, the bottom rail descends. Here, since the bottom rail will fall freely when the operation of the locking mechanism is released, an appropriate braking mechanism may be incorporated in the winding mechanism to reduce its descending speed. As such a braking mechanism, a well-known centrifugal brake is often adopted.

[0003] Patent Document 1 below shows an example of a centrifugal brake. This centrifugal brake comprises a cylindrical housing having an inner circumferential surface with a circular cross-section, and a rotating body that is rotatable inside the housing around the central axis of the inner circumferential surface. The rotating body has a support shaft that extends axially at an eccentric position from the central axis, and a plurality of these support shafts are arranged at intervals in the circumferential direction. Weights are pivotally supported on the plurality of these support shafts. The plurality of weights pivotally supported on each of the plurality of these support shafts are aligned in the axial direction. Such weights consist of a metal weight body and a synthetic resin sliding piece disposed on the outer surface of the weight body, the outer surface of the sliding piece protruding outward from the outer surface of the weight body. The rotating body is further combined with an adjustment member that is locked in the circumferential direction by a locking means and rotates integrally with the rotating body. The adjustment member has an adjustment piece that extends axially at an eccentric position from the central axis, and a plurality of these adjustment pieces are arranged at intervals in the circumferential direction. The locking means allows for stepwise adjustment of the circumferential position of the adjustment member relative to the rotating body. When the rotating body rotates, the weights rotate around the central axis and are pivoted around the support shaft by centrifugal force, with some of the weights positioned axially aligned contacting the inner surface of the housing, while the remaining weights selectively contact either the inner surface of the housing or the inner surface of the adjustment piece, depending on the circumferential position of the adjustment member relative to the rotating body. At this time, the required braking torque acts on the rotating body due to friction when the weights contact and slide against the inner surface of the housing. Therefore, if the number of the remaining weights contacting the inner surface of the housing is changed, the magnitude of the braking torque is also changed. Accordingly, according to the centrifugal brake shown in Patent Document 1 below, the magnitude of the braking torque acting on the rotating body can be adjusted stepwise by changing the circumferential position of the adjustment member relative to the rotating body. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2024-93730 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In the centrifugal brake described in Patent Document 1, the adjustment piece is a rod-shaped piece extending in the axial direction, and when the weight is pressed against the inner surface of the adjustment piece by the centrifugal force, the rod-shaped adjustment piece must support the weight on its own. Therefore, if the adjustment piece is bent by the centrifugal force, it will come into contact with the inner circumferential surface of the housing, and braking torque will be generated unexpectedly, which may prevent the braking torque from being switched sufficiently and reliably.

[0006] Furthermore, in the centrifugal brake shown in Patent Document 1, the inner surface of the adjustment piece contacts the outer surface of the weight body, thereby preventing the outer surface of the sliding piece from contacting the inner circumferential surface of the housing. Since the outer surface of the sliding piece protrudes further outward than the outer surface of the weight body, even a slight shift in the contact position between the inner surface of the adjustment piece and the outer surface of the weight body due to manufacturing variations, etc., can cause the outer surface of the sliding piece to contact the inner circumferential surface of the housing body, unexpectedly generating braking torque and potentially preventing the braking torque from being switched sufficiently and reliably.

[0007] The present invention has been made in view of the above facts, and its main technical objective is to provide a novel and improved centrifugal brake that can reliably and sufficiently switch braking torque. [Means for solving the problem]

[0008] As a result of diligent research, the inventors have found that the main technical problems described above can be solved by connecting the tips of multiple adjustment pieces to each other with connecting rings, or by selectively bringing a synthetic resin sliding piece, which is disposed on the outer surface of the weight body, into contact with the inner surface of the housing or the inner surface of the adjustment piece.

[0009] That is, according to the first aspect of the present invention, as a centrifugal brake that solves the above main technical problem, the present invention comprises a cylindrical housing having an inner circumferential surface with a circular cross-section, and a rotating body that is rotatable inside the housing about the central axis of the inner circumferential surface, The rotating body has a support shaft extending axially at an eccentric position from the central axis, and a plurality of these support shafts are arranged at intervals in the circumferential direction, and weights are pivotably supported on each of the plurality of support shafts, and the plurality of weights supported on each of the plurality of support shafts are aligned in the axial direction. The rotating body is further equipped with an adjustment member that is circumferentially locked by a locking means and rotates integrally with the rotating body, the adjustment member having an adjustment piece that extends axially at an eccentric position from the central axis, and the locking means is capable of stepwise adjustment of the circumferential position of the adjustment member relative to the rotating body. In a centrifugal brake, when the rotating body rotates, the weights rotate around the central axis and pivot around the support shaft, with some of the weights positioned in alignment in the axial direction contacting the inner circumferential surface of the housing, while the remaining weights selectively contact the inner circumferential surface of the housing or the inner surface of the adjustment piece, depending on the circumferential position of the adjustment member relative to the rotating body, A centrifugal brake is provided, characterized in that a plurality of adjustment pieces are arranged at intervals in the circumferential direction, and the tips of the plurality of adjustment pieces are connected to each other by connecting rings.

[0010] Preferably, the multiple support shafts are arranged at equal angular intervals in the circumferential direction. The adjustment piece is a thin plate piece with a circular arc cross-section, and it is preferable that the outer and inner surfaces of the adjustment piece are continuous in the axial direction with the outer and inner surfaces of the connecting ring.

[0011] Furthermore, according to a second aspect of the present invention, as a centrifugal brake that solves the above-mentioned main technical problems, the present invention comprises a cylindrical housing having an inner circumferential surface with a circular cross-section, and a rotating body that is rotatable inside the housing about the central axis of the inner circumferential surface, The rotating body has a support shaft extending axially at an eccentric position from the central axis, and a plurality of these support shafts are arranged at intervals in the circumferential direction, and weights are pivotably supported on each of the plurality of support shafts, and the plurality of weights supported on each of the plurality of support shafts are aligned in the axial direction. The rotating body is further equipped with an adjustment member that is circumferentially locked by a locking means and rotates integrally with the rotating body, the adjustment member having an adjustment piece that extends axially at an eccentric position from the central axis, and the locking means is capable of stepwise adjustment of the circumferential position of the adjustment member relative to the rotating body. In a centrifugal brake in which the rotating body rotates, the weight rotates around the central axis and pivots around the support shaft, The weight consists of a weight body and a sliding piece disposed on the outer surface of the weight body, the outer surface of the sliding piece protrudes outward from the outer surface of the weight body. A centrifugal brake is provided, characterized in that, when the rotating body rotates, some of the sliding pieces of the plurality of weights positioned in alignment in the axial direction contact the inner circumferential surface of the housing, while the sliding pieces of the remaining weights selectively contact the inner circumferential surface of the housing or the inner surface of the adjusting piece, depending on the circumferential position of the adjusting member relative to the rotating body.

[0012] Preferably, the adjustment piece is a thin plate piece with a circular arc cross-section. [Effects of the Invention]

[0013] According to the first aspect of the present invention, since the tips of the multiple adjustment pieces are interconnected by a connecting ring, even if a weight comes into contact with the inner surface of an adjustment piece due to centrifugal force and pushes it radially outward, the pushed adjustment piece is supported by the connecting ring and the other adjustment pieces connected thereto, thus preventing the pushed adjustment piece from bending. This prevents the adjustment piece from unexpectedly coming into contact with the inner circumferential surface of the housing and generating braking torque, and allows for sufficiently reliable switching of the braking torque.

[0014] Furthermore, according to a second aspect of the present invention, since the outwardly protruding synthetic resin sliding piece is pre-set to selectively contact the inner surface of the adjustment piece or the inner circumferential surface of the housing, even if the contact position between the outer surface of the sliding piece and the inner surface of the adjustment piece is slightly shifted due to manufacturing variations, etc., it is prevented that the outer surface of the sliding piece will unexpectedly contact the inner circumferential surface of the housing and generate braking torque when the rotating body rotates, and the braking torque can be switched sufficiently and reliably.

[0015] It should be noted in advance that the applicant of this application filed a prior application for and has already been granted a patent in Japanese Patent Publication No. 7039761, which describes a centrifugal brake similar to the centrifugal brake relating to the first aspect of the present invention (referred to as the "first reference centrifugal brake"), and the applicant of this application filed a prior application for and has already been granted a patent in Japanese Patent Publication No. 7015363, which describes a centrifugal brake similar to the centrifugal brake relating to the second aspect of the present invention (referred to as the "second reference centrifugal brake"). The adjustment member of the first reference centrifugal brake also has a plurality of adjustment pieces, and the tips of the plurality of adjustment pieces are connected to each other by a connecting ring. In the second reference centrifugal brake as well, the outwardly protruding sliding piece made of synthetic resin is set to contact the inner surface of the adjustment piece. However, in the first and second reference centrifugal brakes, multiple weights arranged in series in the axial direction (i.e., on different levels) selectively contact the inner surface of the adjustment piece or the inner circumferential surface of the housing, whereas in the centrifugal brakes according to the first and second phases of the present invention, multiple weights arranged on the same level selectively contact the inner surface of the adjustment piece or the inner circumferential surface of the housing. This is a difference between the first and second reference centrifugal brakes and the centrifugal brakes according to the first and second phases of the present invention. When multiple weights are arranged on the same level, the axial length of the adjustment piece can be shorter than when they are arranged on different levels, making the adjustment piece less prone to bending. If the adjustment piece bends, as described above, it may unexpectedly contact the inner circumferential surface of the housing, generating braking torque, which could prevent the braking torque from being switched sufficiently and reliably. In other words, by arranging multiple weights on the same hierarchical level, the centrifugal brake according to the first aspect of the present invention and the centrifugal brake according to the second aspect of the present invention have advantageous effects compared to the first reference centrifugal brake and the second reference centrifugal brake. [Brief explanation of the drawing]

[0016] [Figure 1] A diagram showing the overall configuration of a preferred embodiment of a centrifugal brake configured according to the present invention. [Figure 2] Figure 1 shows an exploded perspective view of a centrifugal brake. [Figure 3]A view showing the housing of the centrifugal brake shown in Fig. 1 alone. [Figure 4] A view showing the rotating body of the centrifugal brake shown in Fig. 1 alone. [Figure 5] A view showing the weight of the centrifugal brake shown in Fig. 1 alone. [Figure 6] A view showing the adjusting member of the centrifugal brake shown in Fig. 1 alone. [Figure 7-1] A view for explaining the operation of the centrifugal brake shown in Fig. 1. [Figure 7-2] A view for explaining the operation of the centrifugal brake shown in Fig. 1. [Figure 7-3] A view for explaining the operation of the centrifugal brake shown in Fig. 1. [Figure 8] A view showing the overall configuration of another embodiment of the centrifugal brake configured according to the present invention. [Figure 9-1] A view for explaining the operation of the centrifugal brake shown in Fig. 8. [Figure 9-2] A view for explaining the operation of the centrifugal brake shown in Fig. 8.

Embodiments for Carrying out the Invention

[0017] Hereinafter, a more detailed description will be given with reference to the accompanying drawings showing preferred embodiments of the centrifugal brake configured according to the present invention. In the following description, "one side" and "the other side" in the axial direction are based on the state shown in the A-A cross-sectional view of Fig. 1 or the A-A cross-sectional view of Fig. 8, unless otherwise specified. In the same figure, the left side is "one side" and the right side is "the other side".

[0018] Figure 1 shows a preferred embodiment of a centrifugal brake configured according to the present invention, indicated by number 2. Figure 1(a) is a cross-sectional view AA, which is the central longitudinal section of the centrifugal brake 2, (b) is a cross-sectional view BB of the centrifugal brake 2, and (c) is a right side view of the centrifugal brake 2. Referring to Figures 1 and 2, the centrifugal brake 2 comprises a housing 4 and a rotating body 6. Referring to Figure 3, the housing 4 is a cylindrical shape molded from a relatively hard synthetic resin, extending axially through it, and has an inner circumferential surface 8 with a circular cross-section. The central axis of the inner circumferential surface 8 is indicated by the lowercase letter o. An annular support wall 10 is formed at one axial end of the inner circumferential surface 8, projecting radially inward and extending continuously in the circumferential direction. The base end of an extension piece 12, which extends linearly to one side in the axial direction beyond the axial edge of the outer circumferential surface of the housing 4, is connected to one axial end of the outer circumferential surface of the housing 4. One extension piece 12 is provided on each side in the diametrical direction. An axial locking projection 14 is formed on the outer surface of the extended end, or one axial end, of the extended piece 12. Further, a pair of ears 16 projecting radially outward are formed on both sides in the diametrical direction at one axial end of the outer circumferential surface of the housing 4, and a cylindrical positioning pin 18 projecting toward one axial side is erected on each of the pair of ears 16. The axial locking projection 14 and the positioning pin 18 are arranged alternately at 90-degree angular intervals in the circumferential direction. The axial locking projection 14 and the positioning pin 18 are used when connecting the rotating body 6 to the speed increaser X, which will be described later. A protective piece 20 extending toward the other axial side is provided on the other axial end surface of the housing 4. In the illustrated embodiment, four protective pieces 20 are arranged at equal angular intervals in the circumferential direction. The outer and inner surfaces of each protective piece 20 are continuous with the inner and outer circumferential surfaces 8 and circumferential surfaces of the housing 4, and the extended ends of the protective pieces 20 are arc-shaped. When the housing 4 is assembled with the rotating body 6, as shown in the cross-sectional view AA of Figure 1, the extended end of the protective piece 20, i.e., the axial opposite end, is located axially opposite to the extended end of the locking piece 40 of the rotating body 6, i.e., the axial opposite end, and the protective piece 20 protects the extended end of the locking piece 40.

[0019] The rotating body 6 is rotatable inside the housing 4 with respect to the central axis o of the inner circumferential surface 8 of the housing 4 as its axis of rotation. Referring to Figures 1 and 2, and also to Figure 4, the rotating body 6 is made of synthetic resin and has a cylindrical rotating main shaft 22 that extends linearly along the central axis o and penetrates axially. The rotating main shaft 22 has a circular cross-section except for one end on its axial side, and a sun gear 24 is formed on this axial end. A rotation transmission shaft of, for example, a blind winding mechanism is connected to the sun gear 24 via a suitable speed increaser X, shown by the dashed line in Figure 1. Therefore, the rotation of such a rotation transmission shaft is accelerated by the speed increaser X and transmitted to the rotating body 6. The rotating main shaft 22 also has a disc-shaped rotating side wall 26 and a rotating other side wall 28, which are spaced apart in the axial direction and both increase the outer diameter of the rotating main shaft 22. The rotating side wall 26 is positioned somewhat axially away from the sun gear 24, and the rotating other side wall 28 is positioned at the axially opposite end of the rotating main shaft 22. The outer diameter of the rotating side wall 26 is equal to the outer diameter of the rotating other side wall 28, but the axial width of the rotating side wall 26 is thicker than the axial width of the rotating other side wall 28. An annular rotating flange 30 is provided at one axial end of the outer circumferential surface of the rotating side wall 26, projecting radially outward. As shown in the AA cross-sectional view of Figure 1, the outer circumferential edge of the axially opposite side of the rotating flange 30 faces one axial side of the support wall 10 of the housing 4. Four fan-shaped cutouts 32 are formed on one axial side of the rotating side wall 26 at circumferential intervals. On the other hand, the rotating other side wall 28 has one substantially rectangular window 34 on each side in the diametrical direction that communicates axially. The rotating body 6 has a support shaft 36 that extends axially at an eccentric position from the central axis o. In the illustrated embodiment, both ends of the support shaft 36 are connected to the rotating one-sided wall 26 and the rotating other-sided wall 28; in other words, the support shaft 36 is double-supported by the rotating one-sided wall 26 and the rotating other-sided wall 28. Six such support shafts 36 are arranged at equal angular intervals in the circumferential direction. Of the six support shafts 36, two support shafts 36 located on both sides in the diametrical direction are positioned in alignment with windows 34 formed one on each side in the diametrical direction, and the outer surfaces of the base ends of these two support shafts 36 are also connected to the inner surfaces of the rotating other-sided wall 28 that define the windows 34. Such a support shaft 36 has the required cross-sectional shape.A cylindrical auxiliary wall 38 is formed on the inner peripheral edge of the axial side of the non-rotating side wall 28, extending continuously in the circumferential direction. A locking piece 40 is also formed on the axial side of the non-rotating side wall 28, extending toward the other axial direction, with the inner surface of its base end connected to the outer surface of the auxiliary wall 38. One locking piece 40 is provided on each side in the diametrical direction. A locking projection 42 is formed on the outer surface of the tip of the locking piece 40, projecting radially outward.

[0020] Each of the six support shafts 36 is pivotally supported by a weight 44, and the six weights 44 are aligned in the axial direction. As will be described later, in the illustrated embodiment, the weights 44 arranged on both sides in the diametrical direction perform the same operation, so when referring to each of the six weights 44, they are referred to by denoting a to c, for example, as shown in the BB cross-sectional view of Figure 1. Therefore, in the illustrated embodiment, there are three pairs of weights 44 spaced apart in the circumferential direction on the same plane: a pair of weights 44a and 44a, a pair of weights 44b and 44b, and a pair of weights 44c and 44c. Continuing the explanation with reference to Figures 1 and 2, and Figure 5, in the illustrated embodiment, the weight 44 consists of a metal weight body 46 and a relatively soft synthetic resin sliding piece 48. The weight body 46 has an arc shape when viewed in the axial direction and has the required axial width. A mounting groove 50 on one side and a mounting groove 52 on the other side are formed on the outer surface of the weight body 46, extending linearly in the axial direction and penetrating through it. The mounting groove 50 on one side and the mounting groove 52 on the other side each have the required cross-sectional shape. The sliding piece 48 comprises a base portion 48a that fits into the mounting groove 50 on one side, and an exposed portion 48b whose outer surface is located outward from the outer surface of the weight body 46, as shown in the BB cross-sectional view of Figure 1, etc., when the base portion 48a is fitted into the mounting groove 50 on one side. The axial width of the sliding piece 48 corresponds to the axial width of the mounting groove 50 on one side. The weight 44 is pivotably supported on the support shaft 36 by mounting the support shaft 36 of the rotating body 6 in the mounting groove 52 on the other side of the weight body 46 with the sliding piece 48 mounted on the weight body 46. Mounting the support shaft 36 of the rotating body 6 to the mounting groove 52 on the other side of the weight body 46 is carried out, for example, in the manner shown in Japanese Patent No. 7052122, which was filed and patented prior to this application by the applicant of the present application. When the weight 44 is attached to the support shaft 36, the inner surface of the weight body 46 faces the outer surface of the rotating main shaft 22 of the rotating body 6.

[0021] The rotating body 6 is further combined with an adjustment member 54 that rotates integrally with it. Referring to Figure 6 in conjunction with Figures 1 and 2, the adjustment member 54 has a disc-shaped adjustment base wall 56 that is positioned perpendicular to the axial direction. The adjustment base wall 56 is located at the other axial end on the inside of the housing 4, and one axial side of the adjustment base wall 56 faces, approaches, or abuts against the other axial side of the rotating other side wall 28 of the rotating body 6. A circular fitting hole 58 that penetrates axially is formed in the center of the adjustment base wall 56. As shown in Figure 1(c), the auxiliary wall 38 of the rotating body 6 is fitted into the fitting hole 58, preventing so-called runout between the adjustment member 54 and the rotating body 6. The inner circumferential surface of the adjustment base wall 56 has one arc-shaped recess 60 on each side in the diametrical direction, with the inner diameter locally increased. Four arc-shaped windows 62 that penetrate axially are formed at circumferential intervals on the outer peripheral edge of the adjustment base wall 56. The adjustment member 54 has an adjustment piece 64 that extends axially at an eccentric position from the central axis o. In the illustrated embodiment, the adjustment piece 64 is a thin plate with an arc-shaped cross-section that extends axially from the outer peripheral edge of one axial side surface of the adjustment base wall 56 to the other axial side, and is positioned between the outer surface of the weight 44 and the inner circumferential surface 8 of the housing 4. As can be understood by referring to the AA cross-sectional view in Figure 1, the extended end face of the adjustment piece 64, i.e., the axial end face on one side, faces the axial other side of the support wall 10 of the housing 4, and the inner surface of the extended end, i.e., the axial end face, faces the outer peripheral surface of the rotating side wall 26 of the rotating body 6. Four such adjustment pieces 64 are arranged at intervals in the circumferential direction. The four adjustment pieces 64 consist of a pair of first adjustment pieces 64a and 64a and a pair of second adjustment pieces 64b and 64b, which are arranged on both sides in the diametrical direction. The first adjustment piece 64a has a narrower circumferential width than the second adjustment piece 64b, and the first adjustment piece 64a and the second adjustment piece 64b have a required circumferential spacing. Here, in the centrifugal brake configured according to the present invention, it is important that the tips of the multiple adjustment pieces 64 are connected to each other by a connecting ring 66.

[0022] Continuing the explanation mainly with reference to Figure 6, a cylindrical bulge 68 is provided on the other axial side of the adjustment base wall 56, surrounding the outer peripheral edge of the fitting hole 58 and recess 60 and bulging out in the other axial direction. As shown in the AA cross-sectional view of Figure 1, the locking piece 40 of the rotating body 6 passes inside the bulge 68. Multiple locking recesses 70 corresponding to the number of weights 44 are formed at circumferential intervals on the other axial end face of the bulge 68. The circumferential region where the multiple locking recesses 70 are formed coincides with the circumferential region where the recess 60 is formed. A locking projection 42 provided on the rotating body 6 can be locked into each of the multiple locking recesses 70, and when the locking projection 42 is locked into the locking recess 70, the adjustment member 54 rotates together with the rotating body 6. Therefore, the locking projection 42 and the locking recesses 70 constitute the locking means. In the illustrated embodiment, since three pairs of weights 44 are arranged on the same plane at intervals in the circumferential direction, three locking recesses 70 are formed at intervals in the circumferential direction. When referring to each of the three locking recesses 70, they are sequentially designated a to c in one direction in the circumferential direction. In the illustrated embodiment, since one locking piece 40 and one locking projection 42 are provided on each side in the diametrical direction, one locking recess 70a to 70c are also formed on each side in the diametrical direction. A pair of gripping parts 72 connected to the outer circumferential surface of the bulge 68 are also provided on the other axial side of the adjustment base wall 56.

[0023] Next, the operation of the centrifugal brake 2 configured according to the present invention will be described with reference to Figures 1 and 7-1 to 7-3. In the state shown in Figure 1, the locking projection 42 formed on the locking piece 40 of the rotating body 6 is locked into the locking recess 70a formed on the bulge 68 of the adjustment member 54, and the rotating body 6 is not rotating.

[0024] Figure 7-1 shows the state in which the rotating body 6 is rotating while the locking projection 42 of the rotating body 6 is locked in the locking recess 70a of the adjustment member 54. In the same figure, (a) is a perspective view with the housing 4 omitted, (b) is a diagram corresponding to the BB cross-sectional view in Figure 1, and (c) is a diagram corresponding to the right side view in Figure 1 (the same applies to Figures 7-2 and 7-3 described later). It is preferable that the rotating body 6 rotates counterclockwise when viewed from one side to the other in the axial direction (clockwise in the BB cross-sectional view in Figure 1). When the rotating body 6 rotates, all the weights 44 and the adjustment member 54 rotate together with the rotating body 6 around the central axis o. At this time, all the weights 44 are further rotated around the support shaft 36 by the centrifugal force caused by the above rotation, and the outer surfaces of the sliding pieces 48 of each of the pair of weights 44a and 44a come into contact with the inner surfaces of each of the pair of adjustment pieces 64a and 64a, the outer surfaces of the sliding pieces 48 of each of the pair of weights 44b and 44b come into contact with the inner surfaces of each of the pair of adjustment pieces 64b and 64b, and the outer surfaces of the sliding pieces 48 of each of the pair of weights 44c and 44c come into contact with the inner circumferential surface 8 of the housing 4. Therefore, in the state shown in Figure 7-1, only the outer surfaces of the sliding pieces 48 of each of the pair of weights 44c and 44c are pressed against the inner circumferential surface 8 of the housing 4 by the above centrifugal force and slide against the inner circumferential surface 8, and a brake (braking torque) due to friction caused by the above sliding acts on the rotating body 6. In the illustrated embodiment, the housing 4 is made of a relatively hard synthetic resin, while the sliding piece 48 of the weight 44 is made of a relatively soft synthetic resin. This prevents uneven wear of only the replaceable sliding piece 48 and thus prevents wear of the inner circumferential surface of the housing 4.

[0025] To increase the magnitude of the braking torque described above beyond the state shown in Figure 7-1, the adjustment member 54 is rotated counterclockwise when viewed from the other axial side to one side relative to the rotating body 6 (and therefore in the right side view of Figure 1). Figure 7-2 shows the state in which the rotating body 6 is rotating when the locking projection 42 is locked into the locking recess 70b. As can be understood by comparing Figure 7-2 with Figure 7-1, in the state shown in Figure 7-2, in addition to the outer surfaces of the sliding pieces 48 of the pair of weights 44c and 44c, the outer surfaces of the sliding pieces 48 of the pair of weights 44a and 44a also contact and slide against the inner circumferential surface 8 of the housing 4, thus increasing the braking torque applied to the rotating body 6. The outer surfaces of the sliding pieces 48 of the pair of weights 44b and 44b continue to contact the inner surfaces of the pair of adjustment pieces 64b and 64b of the adjustment member 54 and do not contact the inner circumferential surface 8 of the housing 4. Figure 7-3 shows the state in which the rotating body 6 is rotating when the locking projection 42 is locked into the locking recess 70c, after the adjustment member 54 has been further rotated in the above direction relative to the rotating body 6. As can be understood by comparing Figure 7-3 with Figure 7-2, in the state shown in Figure 7-3, in addition to the outer surfaces of the sliding pieces 48 of the pair of weights 44c and 44c and the pair of weights 44a and 44a, the outer surfaces of the sliding pieces 48 of the pair of weights 44b and 44b also come into contact with the inner circumferential surface 8 of the housing 4 and slide against it, so the braking torque applied to the rotating body 6 is further increased.

[0026] In other words, as the rotating body 6 rotates, all the weights 44 (a pair of weights 44a and 44, 44b and 44b, and 44c and 44c) are rotated around the central axis o and pivoted around the support shaft 36, with some of the weights 44 (a pair of weights 44c and 44c) contacting the inner circumferential surface 8 of the housing 4, while the remaining weights 44 (a pair of weights 44a and 44a, and 44b and 44b) selectively contact either the inner circumferential surface 8 of the housing 4 or the inner surface of the adjustment piece 64, depending on the circumferential position of the adjustment member 54 relative to the rotating body 6.

[0027] In the centrifugal brake of the present invention, since the tips of the multiple adjustment pieces 64 are interconnected by a connecting ring 66, even if the weight 44 contacts the inner surface of the adjustment piece 64 due to centrifugal force and pushes it radially outward, the pushed adjustment piece 64 is supported by the connecting ring 66 and the other adjustment pieces 64 connected thereto, thus preventing the pushed adjustment piece 64 from bending. This prevents the adjustment piece 64 from unexpectedly contacting the inner circumferential surface 8 of the housing 4 and generating braking torque, and allows for sufficiently reliable switching of the braking torque. Furthermore, in the centrifugal brake of the present invention, the outwardly protruding synthetic resin sliding piece 48 is pre-set to selectively contact the inner surface of the adjustment piece 64 or the inner circumferential surface 8 of the housing 4. Therefore, even if the contact position between the outer surface of the sliding piece 48 and the inner surface of the adjustment piece 64 is slightly shifted due to manufacturing variations, etc., it is prevented that the outer surface of the sliding piece 48 will unexpectedly contact the inner circumferential surface 8 of the housing 4 when the rotating body 6 rotates, thereby preventing the generation of braking torque and ensuring that the braking torque can be switched sufficiently and reliably.

[0028] Figure 8 shows another embodiment of a centrifugal brake configured according to the present invention. The configuration of the centrifugal brake shown in Figure 8 is basically the same as the configuration of centrifugal brake 2 described above, but the two brakes differ in that centrifugal brake 2 can adjust the braking torque in three stages, while the centrifugal brake shown in Figure 8 can adjust the braking torque in two stages. In the following description, configurations identical to those of centrifugal brake 2 described above will be numbered 100, and detailed explanations will be omitted. Figure 8(a) is a cross-sectional view AA, which is the central longitudinal section of centrifugal brake 102, (b) is a cross-sectional view BB of centrifugal brake 102, and (c) is a right side view of centrifugal brake 102.

[0029] In the centrifugal brake 102 of this embodiment, four weights 144 are provided, consisting of a pair of weights 144a and 144a arranged on both sides in the diametrical direction, and a pair of weights 144b and 144b. Accordingly, the adjustment member 154 is provided with a pair of adjustment pieces 164a and 164a and two locking recesses, namely locking recesses 170a and 170b. In this embodiment as well, the extended ends, namely one axial end, of each of the pair of adjustment pieces 164a and 164b are connected by a connecting ring.

[0030] In the state shown in Figure 8, the locking projection 142 of the rotating body 106 is locked into the locking recess 170a of the adjustment member 154, and the rotating body 106 is not rotating. Figure 9-1 shows the state in which the rotating body 106 is rotating while the locking projection 142 of the rotating body 106 is locked into the locking recess 170a of the adjustment member 154. In the same figure, (a) corresponds to the BB cross section of Figure 8, and (b) corresponds to the right side view of Figure 8 (the same applies to Figure 9-2, which will be described later). When the rotating body 106 rotates, all the weights 144 and the adjustment member 154 rotate together with the rotating body 106 around the central axis o. At this time, all the weights 144 are further rotated around the support shaft 136 by the centrifugal force caused by the rotation, and the outer surfaces of the sliding pieces 148 of each of the pair of weights 144a and 144a come into contact with the inner surfaces of each of the pair of adjustment pieces 164a and 164a, while the outer surfaces of the sliding pieces 148 of each of the pair of weights 144b and 144b come into contact with the inner circumferential surface 108 of the housing 104. Therefore, in the state shown in Figure 9-1, only the outer surfaces of the sliding pieces 148 of each of the pair of weights 144b and 144b are pressed against the inner circumferential surface 108 of the housing 104 by the centrifugal force and slide against the inner circumferential surface 108, and a brake (braking torque) due to friction caused by the sliding acts on the rotating body 106. Figure 9-2 shows the state in which the rotating body 106 is rotating while the locking projection 142 of the rotating body 106 is locked in the locking recess 170b of the adjustment member 154. In the state shown in Figure 9-2, in addition to the outer surfaces of the sliding pieces 148 of the pair of weights 144b and 144b, the outer surfaces of the sliding pieces 148 of the pair of weights 144a and 144a also come into contact with the inner circumferential surface 108 of the housing 104 and slide against it, thus increasing the braking torque applied to the rotating body 106.

[0031] Although centrifugal brakes configured according to the present invention have been described in detail above with reference to the attached drawings, the present invention is not limited to the embodiments described above, and appropriate modifications and changes can be made without departing from the present invention. For example, in the illustrated embodiments, the braking torque can be adjusted in two and three stages, but by changing the number of weights, the braking torque can be adjusted in four or more stages. The position and circumferential width of the adjustment piece can be appropriately adjusted depending on the number and position of the weights that are arranged. [Explanation of Symbols]

[0032] 2: Centrifugal brakes 4: Housing 6: Rotating body 8: Inner surface of the housing 36: Support shaft 42: Locking protrusion (locking means) 44: Weight 46: Weight body 48: Sliding piece 54: Adjustment Member 64 (64a and 64b): Adjustment piece 66: Connecting ring 70 (70a to 70c): Locking recess (locking means)

Claims

1. It comprises a cylindrical housing having an inner circumferential surface with a circular cross-section, and a rotating body that is rotatable inside the housing about the central axis of the inner circumferential surface, The rotating body has a support shaft extending axially at an eccentric position from the central axis, and a plurality of these support shafts are arranged at intervals in the circumferential direction, and weights are pivotably supported on each of the plurality of support shafts, and the plurality of weights supported on each of the plurality of support shafts are aligned in the axial direction. The rotating body is further equipped with an adjustment member that is circumferentially locked by a locking means and rotates integrally with the rotating body, the adjustment member having an adjustment piece that extends axially at an eccentric position from the central axis, and the locking means is capable of stepwise adjustment of the circumferential position of the adjustment member relative to the rotating body. In a centrifugal brake, when the rotating body rotates, the weights rotate around the central axis and pivot around the support shaft, with some of the weights positioned in alignment in the axial direction contacting the inner circumferential surface of the housing, while the remaining weights selectively contact the inner circumferential surface of the housing or the inner surface of the adjustment piece, depending on the circumferential position of the adjustment member relative to the rotating body, A centrifugal brake characterized in that multiple adjustment pieces are arranged at intervals in the circumferential direction, and the tips of the multiple adjustment pieces are connected to each other by connecting rings.

2. The centrifugal brake according to claim 1, wherein the plurality of support shafts are arranged at equal angular intervals in the circumferential direction.

3. The centrifugal brake according to claim 1, wherein the adjustment piece is a thin plate piece with a circular arc cross-section, and the outer and inner surfaces of the adjustment piece are continuous in the axial direction with the outer and inner surfaces of the connecting ring.

4. It comprises a cylindrical housing having an inner circumferential surface with a circular cross-section, and a rotating body that is rotatable inside the housing about the central axis of the inner circumferential surface, The rotating body has a support shaft extending axially at an eccentric position from the central axis, and a plurality of these support shafts are arranged at intervals in the circumferential direction, and weights are pivotably supported on each of the plurality of support shafts, and the plurality of weights supported on each of the plurality of support shafts are aligned in the axial direction. The rotating body is further equipped with an adjustment member that is circumferentially locked by a locking means and rotates integrally with the rotating body, the adjustment member having an adjustment piece that extends axially at an eccentric position from the central axis, and the locking means is capable of stepwise adjustment of the circumferential position of the adjustment member relative to the rotating body. In a centrifugal brake in which the rotating body rotates, the weight rotates around the central axis and pivots around the support shaft, The weight consists of a weight body and a sliding piece disposed on the outer surface of the weight body, the outer surface of the sliding piece protrudes outward from the outer surface of the weight body. A centrifugal brake characterized in that, when the rotating body rotates, some of the sliding pieces of the plurality of weights positioned in alignment in the axial direction contact the inner circumferential surface of the housing, while the sliding pieces of the remaining weights selectively contact the inner circumferential surface of the housing or the inner surface of the adjusting piece, depending on the circumferential position of the adjusting member relative to the rotating body.

5. The centrifugal brake according to claim 4, wherein the adjustment piece is a thin plate piece with a circular arc cross-section.

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