TRAINING BENCH

Abstract

A conventional training bench has a problem in that there is a risk of a user being hurt due to a backrest seat inclining more than necessary against the user's intention. A training bench 10 of the present invention mainly has a leg frame 11, a back frame 12, a movable frame 13, a seat part 14, a back seat 15, an angle adjustment mechanism 16, an operation part 17, and a restriction part 18. The angle adjustment mechanism 16 controls and causes the back frame 12 to transition between a fixed state and an angle adjustment state appropriately, so as to prevent the back seat 15 from inclining too much against the user's intention during training. The training bench 10 thus offers excellent safety.

Claims

1. A training bench comprising: a leg frame; a back frame that is supported by the leg frame; a movable frame that has a first end portion turnably disposed relative to the back frame and a second end portion slidably disposed relative to the leg frame; an angle adjustment mechanism that adjusts an inclination angle of the back frame; and an operation part that operates the angle adjustment mechanism, wherein the angle adjustment mechanism forms a fixed state in which turning operation of the movable frame relative to the back frame is stopped so that the back frame is positionally fixed and an angle adjustment state in which turning operation of the movable frame relative to the back frame is permitted to make the inclination angle of the back frame adjustable.

2. The training bench according to claim 1, wherein in conjunction with a single operation of the operation part performed for transition from the fixed state to the angle adjustment state, the angle adjustment mechanism causes the back frame to transition from the angle adjustment state back to the fixed state.

3. The training bench according to claim 2, wherein the angle adjustment mechanism has an angle adjustment gear that is turnably disposed relative to the back frame, a first arm part that is disposed at the back frame and that engages with or separates from the angle adjustment gear, and a second arm part that is disposed at the back frame and that turns in conjunction with operation of the operation part to cause the first arm part to turn, the first end portion of the movable frame is fixed relative to a support shaft part to which the angle adjustment gear is fixed, in the fixed state, the first arm part is engaged with the angle adjustment gear to stop the support shaft part from performing turning operation relative to the back frame, and in the angle adjustment state, the first arm part separates from the angle adjustment gear to permit the support shaft part to perform the turning operation relative to the back frame.

4. The training bench according to claim 3, wherein the angle adjustment mechanism further has a protrusion piece part that is disposed at the first arm part and a guide groove that is formed in the second arm part and that guides the protrusion piece part to cause the first arm part to turn, the back frame transitions from the fixed state to the angle adjustment state when the protrusion piece part moves inside the guide groove, and the back frame transitions from the angle adjustment state to the fixed state when the protrusion piece part comes out of the guide groove after moving inside the guide groove.

5. The training bench according to claim 4, wherein the angle adjustment mechanism further has a movable piece part that is disposed at the second arm part and that performs extension and contraction operation when pressed by the protrusion piece part in one direction, and when the protrusion piece part presses the movable piece part in the one direction after coming out of the guide groove to cause the movable piece part to contract, the protrusion piece part returns back into the guide groove in conjunction with the turning operation of the second arm part.

6. The training bench according to claim 1, wherein a slide link part that slides relative to the leg frame is disposed at the second end portion of the movable frame, and a restriction part is disposed at the slide link part, the restriction part extending toward the back frame to restrict an inclination range of the back frame.

7. The training bench according to claim 2, wherein a slide link part that slides relative to the leg frame is disposed at the second end portion of the movable frame, and a restriction part is disposed at the slide link part, the restriction part extending toward the back frame to restrict an inclination range of the back frame.

8. The training bench according to claim 3, wherein a slide link part that slides relative to the leg frame is disposed at the second end portion of the movable frame, and a restriction part is disposed at the slide link part, the restriction part extending toward the back frame to restrict an inclination range of the back frame.

9. The training bench according to claim 4, wherein a slide link part that slides relative to the leg frame is disposed at the second end portion of the movable frame, and a restriction part is disposed at the slide link part, the restriction part extending toward the back frame to restrict an inclination range of the back frame.

10. The training bench according to claim 5, wherein a slide link part that slides relative to the leg frame is disposed at the second end portion of the movable frame, and a restriction part is disposed at the slide link part, the restriction part extending toward the back frame to restrict an inclination range of the back frame.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0024] FIGS. 1A and 1B are a perspective view and a side view, respectively, illustrating a training bench as an embodiment of the present embodiment.

[0025] FIG. 2 is a perspective view illustrating the training bench as an embodiment of the present invention.

[0026] FIGS. 3A and 3B are a perspective view and an exploded perspective view, respectively, illustrating an angle adjustment mechanism in the training bench as an embodiment of the present invention.

[0027] FIGS. 4A and 4B are each a side view illustrating the operation of the angle adjustment mechanism in the training bench as an embodiment of the present invention.

[0028] FIGS. 5A and 5B are each a side view illustrating the operation of the angle adjustment mechanism in the training bench as an embodiment of the present invention.

[0029] FIG. 6 is a side view illustrating a conventional training bench.

DESCRIPTION OF EMBODIMENTS

[0030] Hereinbelow, a training bench 10 according to an embodiment of the present invention is described in detail based on the drawings. Note that throughout the description of the present embodiment, the same members are basically denoted by the same reference numerals to avoid repetitive description. The up-down direction represents the height direction of the training bench 10, the left-right direction represents the width direction of the training bench 10, and the front-rear direction represents the depth direction of the training bench 10.

[0031] FIG. 1A is a perspective view illustrating the training bench 10 of the present embodiment. FIG. 1B is a side view illustrating the training bench 10 of the present embodiment. FIG. 2 is a perspective view illustrating a back frame 12 and an angle adjustment mechanism 16 of the training bench 10 of the present embodiment. FIG. 3A is a perspective view illustrating the angle adjustment mechanism 16 of the training bench 10 of the present embodiment. FIG. 3B is an exploded perspective view illustrating the angle adjustment mechanism 16 of the training bench 10 of the present embodiment.

[0032] As shown in FIGS. 1A and 1B, the training bench 10 mainly includes a leg frame 11, the back frame 12 supported by the leg frame 11, a movable frame 13 disposed between the leg frame 11 and the back frame 12, a seat part 14 supported by the leg frame 11, a back seat 15 supported by the back frame 12, the angle adjustment mechanism 16 disposed at the back frame 12, an operation part 17 that operates the angle adjustment mechanism 16, and a restriction part 18 that restricts the inclination range of the back frame 12. A user uses the training bench 10 when doing weight training or the like, and during use, adjusts the angle of the back seat 15 relative to the seat part 14 according to, e.g., the training menu or the part of the body to work on.

[0033] The leg frame 11 is a frame for the training bench 10 to stand on a floor surface of a training room or the like and is formed from a material with desired rigidity, such as, for example, an iron material or an aluminum material. The leg frame 11 mainly has two main pillar parts 11A, 11B and two leg parts 11C, 11D disposed at the lower ends of the main pillar parts 11B, 11A, respectively. Since their upper end portions are turnably linked, the main pillar parts 11A, 11B can be collapsed for storage when the training bench 10 is not used.

[0034] The back frame 12 is turnably linked to a link shaft part 24 of the leg frame 11 (see FIG. 2) and has the back seat 15 attached to its front surface side. During training, for example, a user does weight training while leaning on the back seat 15; thus, like the leg frame 11, the back frame 12 is formed from a material with desired rigidity.

[0035] The movable frame 13 supports the back frame 12 from below and is formed from a material with desired rigidity like the leg frame 11. An upper end portion of the movable frame 13 is fixed to a support shaft part 22 (see FIG. 2) that is turnably disposed relative to the back frame 12, so that the movable frame 13 turns relative to the back frame 12 integrally with the support shaft part 22. A lower end portion of the movable frame 13 is slidably disposed at the main pillar part 11A of the leg frame 11.

[0036] Specifically, the movable frame 13 mainly has a main pillar part 13A disposed between the leg frame 11 and the back frame 12 and a slide link part 13B that is disposed at the main pillar part 11A of the leg frame 11 and moves guided by the main pillar part 11A.

[0037] The slide link part 13B has a publicly-known roller structure (not shown) inside and moves along the main pillar part 11A when the roller structure slides on the surface of the main pillar part 11A. As described above, the upper end portion of the main pillar part 13A turns relative to the back frame 12 integrally with the support shaft part 22, and the slide link part 13B moves along the main pillar part 11A in conjunction with this turning, allowing adjustment of the inclination angle of the back frame 12. This structure allows the back frame 12 to be moved from an upright state which is substantially perpendicular to the mount surface to a substantially horizontal, recumbent state.

[0038] The restriction part 18 is a member that restricts the lower limit position of the inclination range of the back frame 12 and moves along the main pillar part 11A integrally with the slide link part 13B. The restriction part 18 is fixed to the upper surface side of the slide link part 13B and extends towards the back seat 15. The back frame 12 abuts the tip end of the restriction part 18 when the back frame 12 comes to a state of being substantially flat with respect to the seat part 14 to prevent the back frame 12 and the back seat 15 from inclining further.

[0039] Even if one of components constituting the angle adjustment mechanism 16 breaks to cause the back frame 12 to incline abruptly, the slide link part 13B does not come out of the main pillar part 11A. Even in the above state where a component in the training bench 10 is broken, the mechanical structure in which the back frame 12 abuts the tip end of the restriction part 18 prevents the back frame 12 and the back seat 15 from inclining further than the flat state, ensuring the safety for the user.

[0040] The seat part 14 mainly has a sitting seat 14A on which a user sits and support frames 14B, 14C that support the sitting seat 14A from below. As shown, a first end portion of the support frame 14B is fixed to the main pillar part 11B of the leg frame 11, and a first end portion of the support frame 14C is turnably attached to the back frame 12. The support frame 14B itself has a publicly-known extension and contraction mechanism, so that the angle and height of the seat part 14 can be adjusted.

[0041] The back seat 15 is formed mainly of a cushion part on which a user leans and is fixed to the back frame 12, so that the back seat 15 turns relative to the leg frame 11 integrally with the back frame 12. The back seat 15 is adjusted to an inclination angle desired by the user when the user operates the operation part 17 and inclines the back frame 12 via the angle adjustment mechanism 16 and the like.

[0042] The operation part 17 is an operation lever substantially in the shape of the letter U and has a pair of handle portions 17A disposed near the left and right edge portions of the back seat 15, respectively. As will be detailed later, part of the operation part 17 is fixed to a second arm part 33 (see FIG. 3A) of the angle adjustment mechanism 16 at the back side of the back seat 15. When a user performs, for example, operation of pulling the operation part 17 frontward, the second arm part 33 turns, causing a first arm part 32 and an angle adjustment gear 31 to transition from an engaged state to a separate state. Then, the angle of the back frame 12 can be adjusted.

[0043] As shown in FIG. 2, the back frame 12 mainly has two main pillar parts 12A, 12B to which the back seat 15 is fixed and two bridge parts 12C, 12D bridging the main pillar parts 12A, 12B in the width direction. Between the bridge parts 12C, 12D, three support shaft parts 21, 22, 23 supporting the angle adjustment mechanism 16 are disposed, bridging link plates 41 fixed to the main pillar parts 12A, 12B. The back frame 12 is turnably supported by the link shaft part 24 of the leg frame 11 and is adjusted to an inclination angle desired by the user by turning in the front-rear direction of the training bench 10 with the link shaft part 24 serving as a rotational pivot point.

[0044] The main pillar parts 12A, 12B are disposed near the left and right edge portions of the back seat 15 to extend in the longitudinal direction, supporting the back seat 15 from its back surface side. The bridge parts 12C, 12D are disposed near both end portions of the main pillar parts 12A, 12B in the height direction, respectively, and are fixed by welding to the main pillar parts 12A, 12B, so that desired rigidity and strength of the back frame 12 is achieved.

[0045] As shown, the support shaft parts 21, 22, 23 are disposed substantially at the center portions of the main pillar parts 12A, 12B in the height direction. The support shaft parts 21, 22, 23 are disposed to bridge the pair of link plates 41 fixed by welding to the main pillar parts 12A, 12B.

[0046] As shown also in FIG. 3B, the support shaft part 21 is bolted at its both end portions and is therefore fixed and does not turn relative to the link plates 41. The support shaft part 22 has an elongate bolt 22A and a hollow cylindrical shaft 22B, the elongate bolt 22A being fixed relative to the link plates 41. The hollow cylindrical shaft 22B is rotatably disposed between the link plates 41 with the elongate bolt 22A being inserted therein, so that the support shaft part 22 is turnable relative to the back frame 12. The support shaft part 23 has an elongate bolt 23A and a hollow cylindrical shaft 23B, the elongate bolt 23A being fixed relative to the link plates 41. The hollow cylindrical shaft 23B is rotatably disposed between the link plates 41 with the elongate bolt 23A being inserted therein, so that the support shaft part 23 is turnable relative to the back frame 12.

[0047] In this structure, the support shaft part 21 is fixed relative to the link plates 41, while the support shaft parts 22, 23 turn relative to the link plates 41 via the hollow cylindrical shafts 22B, 23B. As will be detailed later, when the angle adjustment gear 31 (see FIG. 3A) and the first arm part 32 (see FIG. 3A) are in an engaged state, the support shaft part 22 is fixed to the back frame 12 via the first arm part 32, and consequently, the movable frame 13 is also fixed relative to the back frame 12. When the angle adjustment gear 31 and the first arm part 32 are in a separate state, the support shaft part 22 turns relative to the back frame 12, and consequently the movable frame 13 also turns relative to the back frame 12. Note that the first arm part 32 is turnably supported by the support shaft part 21, the angle adjustment gear 31 is fixed to the support shaft part 22, and the second arm part 33 (see FIG. 3A) is fixed to the support shaft part 23.

[0048] The operation part 17 is fixed relative to the second arm part 33, and the pair of handle portions 17A are disposed at heights substantially one third of the main pillar parts 12A, 12B in the height direction. With this structure, when a user sitting on the seat part 14 (see FIG. 1A) and leaning on the back seat 15 stretches their both hands to the back side, they have easy access to grip and operate the pair of handle portions 17A. In this state, the user pulls the handle portions 17A of the operation part 17 frontward to bring the first arm part 32 and the angle adjustment gear 31 to a separate state and then pushes the back seat 15 rearward with their back, and as a result, the movable frame 13 moves, allowing adjustment of the inclination angle of the back frame 12.

[0049] As shown in FIGS. 3A and 3B, the angle adjustment mechanism 16 mainly has the angle adjustment gear 31 fixed to the support shaft part 22, the first arm part 32 that forms an engage state or a separate state with the angle adjustment gear 31 with the support shaft part 21 serving as a rotational pivot point, the second arm part 33 that turns together with the support shaft part 23 to control the turning operation of the first arm part 32, a first elastic part 34 that biases the first arm part 32 toward the angle adjustment gear 31, a second elastic part 35 that biases the second arm part 33 toward the first arm part 32, a spiral spring 37 disposed at the support shaft part 22, protrusion piece parts 38 fixed to the left and right side surfaces of the first arm part 32, guide grooves 39 formed in the second arm part 33, movable piece parts 40 disposed at the second arm part 33, and third elastic parts 36 (see FIG. 4A) that allow the movable piece parts 40 to move in one direction. For the convenience of illustration, the third elastic parts 36 are not shown.

[0050] The angle adjustment gear 31 is substantially fan-shaped and is formed from a material with desired rigidity, such as, for example, an iron material or an aluminum material. In the arc region of the angle adjustment gear 31, a plurality of tooth profiles 31A are formed, arranged at certain intervals. The angle adjustment gear 31 is fixed by welding to a substantially center area of the support shaft part 22. The angle adjustment gear 31 does not perform turning operation solely, but performs turning operation integrally with the support shaft part 22 relative to the back frame 12.

[0051] The first arm part 32 is formed from, for example, the same material as the angle adjustment gear 31 and is disposed such that at least part thereof faces the plurality of tooth profiles 31A in the arc region of the angle adjustment gear 31. A first end portion 32A of the first arm part 32 is pivotally and turnably supported by the support shaft part 21. A second end portion 32B of the first arm part 32 has a plurality of tooth profiles 32C formed and arranged at certain intervals in a region opposing the arc region of the angle adjustment gear 31, the tooth profiles 32C having substantially the same shapes as the tooth profiles 31A. The region of the first arm part 32 where the tooth profiles 32C are formed is arc-shaped having substantially the same radius of curvature as the region of the angle adjustment gear 31 where the tooth profiles 31A are formed.

[0052] With this structure, the tooth profiles 32C of the first arm part 32 and the tooth profiles 31A of the angle adjustment gear 31 engage with each other, and when the first arm part 32 and the angle adjustment gear 31 are in the engaged state, the support shaft part 22 is fixed relative to the back frame 12 and stops turning. As a result, the movable frame 13 fixed to the support shaft part 22 is also in a fixed state relative to the back frame 12 and supporting the back frame 12 from behind. In other words, when the first arm part 32 and the angle adjustment gear 31 are in the engaged state, the inclination angle of the back frame 12 cannot be adjusted, and the back frame 12 is in a fixed state where the back frame 12 is positionally fixed.

[0053] The pair of protrusion piece parts 38 are disposed on the respective side surfaces of the second end portion 32B of the first arm part 32. Each of the protrusion piece parts 38 is, for example, a columnar bar-shaped body made of the same material as the first arm part 32. The first elastic part 34 is, for example, a coil spring and has a first end portion fixed to the support shaft part 21 and a second end portion fixed to the first arm part 32, so that the first arm part 32 is biased by the first elastic part 34 toward the angle adjustment gear 31.

[0054] The second arm part 33 is formed from, for example, the same material as the angle adjustment gear 31 and is disposed below the angle adjustment gear 31 and the first arm part 32. A first end portion 33A of the second arm part 33 is fixed by welding to a substantially center area of the support shaft part 23. The second arm part 33 does not perform turning operation solely, but performs turning operation integrally with the support shaft part 23 relative to the back frame 12. The second arm part 33 is a box-shaped body having a hollow portion inside, and in the engaged state described above, accommodates part of the angle adjustment gear 31 and the first arm part 32 in the hollow portion and supports these members from below.

[0055] The pair of guide grooves 39 are formed at a second end portion 33B of the second arm part 33 to engage with the protrusion piece parts 38 of the first arm part 32 and guide the protrusion piece parts 38 in conjunction with the movement of the protrusion piece parts 38. As will be detailed later, the movable piece parts 40 capable of extension and contraction operation in one direction are formed on side surfaces of the second arm part 33, near the guide grooves 39. For example, the third elastic part 36 (see FIG. 4A) is disposed at each movable piece part 40. The extension and contraction operation of the third elastic part 36 will be described later using FIGS. 4A to 5B.

[0056] The second elastic part 35 is, for example, a coil spring and has a first end portion fixed to the support shaft part 21 and a second end portion fixed to the second arm part 33, so that the second arm part 33 is biased by the second elastic part 35 toward the angle adjustment gear 31 and the first arm part 32.

[0057] The spiral spring 37 is a member for biasing the back frame 12 frontward and has a first end 37A which is a spiral start point fixed to the support shaft part 22 and a second end 37B which is a spiral end point fixed to the support shaft part 21. With this structure, when the support shaft part 22 turns to cause the back frame 12 to incline rearward, the spiral spring 37 wraps around the support shaft part 22 in a direction to tighten the support shaft part 22, biasing the back frame 12 frontward.

[0058] The first arm part 32 is pivotally and turnably supported by the support shaft part 21 as described above, but is unlikely to be displaced in the left-right direction due to a structure such that the first arm part 32 is disposed inside a recessed portion 21B at a substantially center area of the support shaft part 21. Further, the second arm part 33 is fixed by welding to the support shaft part 23 and is thereby fixed in position, while the first arm part 32 turns guided inside the second arm part 33. This structure makes it difficult for the first arm part 32 to be displaced from the recessed portion 21B of the support shaft part 21.

[0059] Next, FIGS. 4A to 5B are side views illustrating how the angle adjustment mechanism 16 of the training bench 10 of the present embodiment operates, FIGS. 4A, 5A, and 5B showing the first arm part 32 and the angle adjustment gear 31 in the engaged state and FIG. 4B showing the first arm part 32 and the angle adjustment gear 31 in the separate state. Note that FIGS. 4A to 5B do not show some of the components constituting the angle adjustment mechanism 16 for the convenience of illustration.

[0060] First, FIG. 4A shows a state before a user operates the operation part 17, in which state the second arm part 33 supports the angle adjustment gear 31 and the first arm part 32 from below with the first arm part 32 and the angle adjustment gear 31 being in the engaged state. In this state, the second arm part 33 is biased by the second elastic part 35 and is in a state of being closest to the first arm part 32. As a result, the protrusion piece parts 38 of the first arm part 32 abut the bottom surfaces of the guide grooves 39 of the second arm part 33, so that the first arm part 32 is in an unturnable state. The above engaged state is supported by the first arm part 32 being pressed toward the angle adjustment gear 31. Note that the movable piece parts 40 are in a most extended state, without abutting and being pressed by the protrusion piece parts 38.

[0061] As shown, the third elastic part 36 is, for example, a coil spring and has a first end portion fixed to the movable piece part 40 and a second end portion fixed to the second arm part 33. With this structure, the movable piece parts 40 perform extension and contraction operation when pressed by the protrusion piece parts 38 in a direction to contract the third elastic parts 36 (hereinafter referred to as “one direction”). When pressed by the protrusion piece parts 38 in directions other than the one direction (hereinafter referred to as “other directions”), the movable piece parts 40 do not perform the extension and contraction operation and guide the protrusion piece parts 38 along their outer perimeters.

[0062] Next, as shown in FIG. 4B, when the user performs operation of pulling the handle portions 17A of the operation part 17 frontward as indicated by an arrow 42, the second arm part 33 turns, causing the first arm part 32 to separate from the angle adjustment gear 31. Specifically, as indicated by an arrow 43, the second arm part 33 turns integrally with the support shaft part 23 in conjunction with the movement of the operation part 17 to move in a direction away from the angle adjustment gear 31. As a result, the protrusion piece parts 38 move guided by the guide grooves 39 and the movable piece parts 40, so that the first arm part 32 turns in a direction indicated by an arrow 44. The first arm part 32 and the angle adjustment gear 31 thus transition from the engaged state to the separate state.

[0063] When the first arm part 32 and the angle adjustment gear 31 separate from each other as described above, the support shaft part 22 is now in a state of being turnable relative to the back frame 12, and the inclination angle of the back frame 12 can be adjusted when the user pushes the back seat 15 rearward with their back. In other words, the back frame 12 is in an angle adjustment state. Note that the movable piece parts 40 are not pressed by the protrusion piece parts 38 and are therefore in a most extended state.

[0064] Next, as shown in FIG. 5A, when the user continues the operation of pulling the handle portions 17A of the operation part 17 frontward as indicated by an arrow 45 from the state shown in FIG. 4B to cause the second arm part 33 to turn even further, the first arm part 32 is released from the second arm part 33 and returns to the position shown in FIG. 4A, so that the first arm part 32 and the angle adjustment gear 31 are in the engaged state. Specifically, the second arm part 33 turns further in the direction indicated by an arrow 46 in conjunction with the movement of the operation part 17, and consequently, the protrusion piece parts 38 come out of the guide grooves 39. In other words, when the amount of turning of the operation part 17 exceeds the amount of movement of the protrusion piece parts 38 inside the guide grooves 39, the protrusion piece parts 38 are released from the state of being in conjunction via the guide grooves 39. Then, as indicated by an arrow 47, the first arm part 32 is biased by the first elastic part 34 (see FIG. 3A) and returns to the state of being engaged with the angle adjustment gear 31.

[0065] As described above, when the first arm part 32 and the angle adjustment gear 31 are in engagement with each other, the support shaft part 22 is fixed to the back frame 12 and is in an unturnable state. In this engaged state, the back frame 12 does not turn even if the user pushes the back seat 15 rearward with their back, and the back frame 12 is thus in a fixed state.

[0066] In this state, as shown, the protrusion piece parts 38 out of the guide grooves 39 move to the tip end portions of the movable piece parts 40 and press the movable piece parts 40 in the one direction; thus, the movable piece parts 40 are in a slightly contracted state. Note that, as mentioned earlier, FIG. 5A shows a state where the user has pulled the handle portions 17A of the operation part 17 frontward as far as it can get, and the second arm part 33 too has turned to a position farthest from the angle adjustment gear 31.

[0067] Next, as shown in FIG. 5B, as indicated by an arrow 48 when the user performs operation of returning the handle portions 17A of the operation part 17 rearward from the state shown in FIG. 5A, the second arm part 33 turns in the direction indicated by an arrow 49, while the first arm part 32 and the angle adjustment gear 31 stay in the engaged state.

[0068] Specifically, when the second arm part 33 turns in the direction indicated by the arrow 49 in conjunction with the movement of the operation part 17, the protrusion piece parts 38 further press the movable piece parts 40 in the one direction, causing the movable piece parts 40 to contract. As a result, the protrusion piece parts 38 return back into the guide grooves 39 which have returned integrally with the second arm part 33. Note that the operation part 17 is biased in the direction indicated by an arrow 48 by an elastic part (not shown) such as a coil spring, and the handle portions 17A return to the position shown in FIG. 4A when the user releases the handle portions 17A.

[0069] After the handle portions 17A of the operation part 17 return to the pre-operation state shown in FIG. 4A, the protrusion piece parts 38 also return to the positions abutting the bottom surfaces of the guide grooves 39, and the members constituting the angle adjustment mechanism 16 return to the pre-operation state shown in FIG. 4A. As thus described, the operation from FIGS. 4A to 5B is repeated at the angle adjustment mechanism 16 when the user operates the operation part 17 once.

[0070] In the present embodiment, as described above, during a single operation of the user pulling the handle portions 17A of the operation part 17 frontward for adjustment of the angle of the back frame 12, the first arm part 32 and the angle adjustment gear 31 transition from the engaged state shown in FIG. 4A to the separate state shown in FIG. 4B and then returns to the engaged state shown in FIG. 5A.

[0071] This structure prevents the back frame 12 from inclining too much against the user's intention because the back frame 12 transitions from the angle adjustment state to the fixed state using a mechanical mechanism not dependent on the user's intention. Specifically, the angle adjustment state lasts approximately one second although it depends on the speed at which the user operates the operation part 17, and for this reason, the back frame 12 is prevented from inclining too much against the user's intention during that state. As a result, although the user usually adjusts the angle of the back seat 15 without looking at the angle adjustment mechanism 16, the user is prevented from hurting themselves unexpectedly during that operation. Thus, the training bench 10 offers excellent safety.

[0072] Further, in the training bench 10, the angle of the back seat 15 can be adjusted within substantially 90° from the substantially upright state to the substantially flat state relative to the seat part 14. The angle adjustment mechanism 16 allows angle adjustment for each span of the tooth profiles 31A, 32C, making possible fine adjustments in, for example, 16 stages or the like within the above substantially 90°. As a result, the user can easily adjust the back seat 15 to a desired angle according to the training menu, and therefore the convenience is improved.

[0073] Depending on the amount of turning of the back seat 15, the tooth profiles 31A, 32C may not mesh with each other perfectly at the transition from the non-engaged state to the engaged state. However, the tooth profiles 31A, 32C come into the engaged state immediately because the tooth profiles 31A, 32C have a short span. As a result, the amount by which the back seat 15 slides rearward against the user's intention is small, and therefore the training bench 10 offers excellent safety. Further, unlike a locking structure using a lock pin, the tooth profiles 31A, 32C always come to engage with each other. Thus, the user is freed from the subtle angle adjustment for aligning the lock pin with the lock hole, which is required by the conventional structure, and therefore, the handleability is improved.

[0074] In the present embodiment described above, the back frame 12 is prevented from inclining too much because the mechanical mechanism of the angle adjustment mechanism 16 forces the first arm part 32 and the angle adjustment gear 31 to return from the separate state to the engaged state in a single operation of pulling the operation part 17 frontward for adjustment of the angle of the back frame 12. However, the present invention is not limited to this case. For example, an operation restriction mechanism (not shown) may be disposed near the operation part 17 so that the amount of turning of the operation part 17 may be smaller than the amount of movement of the protrusion piece parts 38 inside the guide grooves 39. In this case, when the user keeps the state where the operation part 17 is pulled frontward, the first arm part 32 and the angle adjustment gear 31 stay in the separate state. Then, when the movable frame 13 turns relative to the back frame 12 with the back frame 12 staying in the angle adjustment state, the user can freely adjust the angle of the back frame 12. In other words, the training bench 10 may be provided with the operation restriction mechanism and used to switch between a mode where the first arm part 32 and the angle adjustment gear 31 are forced to return from the separate state to the engaged state and a mode where the separate state is maintained. Various other modifications can also be made without departing from the gist of the present invention.

REFERENCE SIGNS LIST

[0075] 10 training bench [0076] 11 leg frame [0077] 12 back frame [0078] 13 movable frame [0079] 14 seat part [0080] 15 back seat [0081] 16 angle adjustment mechanism [0082] 17 operation part [0083] 18 restriction part [0084] 21, 22, 23 support shaft part [0085] 31 angle adjustment gear [0086] 32 first arm part [0087] 33 second arm part [0088] 34 first elastic part [0089] 35 second elastic part [0090] 36 third elastic part [0091] 38 protrusion piece part [0092] 39 guide groove [0093] 40 movable piece part