Engagement chain type device for forward and backward movement operation

1. An interlocking chain type forward and backward actuating device comprising a pair of interlocking chains, a drive sprocket, and a chain guide, wherein

the interlocking chains are each composed by coupling, in the chain longitudinal direction, a plurality of pairs of hook-shaped inner tooth plates facing each other in the chain width direction and a plurality of pairs of hook-shaped outer tooth plates arranged on the outer sides of the hook-shaped inner tooth plates in the chain width direction by pairs of front and rear connecting pins,

the interlocking chains are integrally made rigid to form a rigid chain part in a state where the interlocking chains are interlocked with each other and arranged to face each other,

the interlocking chains are disengaged from each other to bifurcate,

the drive sprocket engages with a first one of the pair of interlocking chains from the side face of the rigid chain part to freely advance and retreat the pair of interlocking chains, and

the chain guide has chain guide grooves that interlock a second one of the interlocking chains with the first interlocking chain to drive the second interlocking chain so as to follow the first interlocking chain,

wherein a pair of planar chain support faces sandwiching and supporting the rigid chain part from both sides of the rigid chain part is provided,

the planar chain support faces constitute parts of the guide groove faces of the chain guide grooves in a state where the planar chain support faces are continuous to a pair of curved guide faces, which respectively guide chain disengaged portions of the interlocking chains disengaged from each other,

the planer chain support faces are arranged to face an interlocked portion between the interlocking chains forming the rigid chain part,

the connecting pins of the first interlocking chain include a first connecting pin, which is located on an imaginary boundary plane dividing the planar chain support face and the curved guide face,

the connecting pins of the second interlocking chain include a second connecting pin, which faces the first connecting pin along the imaginary boundary plane,

the distance between the first connecting pin and the second connecting pin is defined as a pin-to-pin distance on the imaginary boundary plane,

the connecting pins of the rigid chain part include a pair of connecting pins that face each other in parallel to the imaginary boundary plane dividing the planar chain support face and the curved guide face, the distance between the pair of connecting pins is defined as a pin-to-pin distance in a rigid state, and

the pin-to-pin distance on the imaginary boundary plane is equal to the pin-to-pin distance in a rigid state.

2. The interlocking chain type forward and backward actuating device according to claim 1 , wherein the planar chain support face extends from the imaginary boundary plane for a distance equal to or longer than a pin-to-pin distance between the pair of front and rear connecting pins.

3. The interlocking chain type forward and backward actuating device according to claim 1 , wherein

a drive sprocket housing groove is formed in the chain guide,

the drive sprocket housing groove has an opening opened toward the side face of the rigid chain part and houses the drive sprocket,

the opening has two opening ends, one of which is defined as an imaginary boundary plane side opening end formed on the side closer to the imaginary boundary plane, and

the terminal end of the planar chain support face overlaps with the imaginary boundary plane side opening end.

4. The interlocking chain type forward and backward actuating device according to claim 1 , wherein the pair of hook-shaped inner tooth plates are spaced from each other in the chain width direction,

a positioning chain guide portion is provided in a fork region of the pair of interlocking chains, and

the positioning chain guide portion includes

a mountain-shaped chain guide portion that guides the chain disengaged portions along flared facing guide faces facing the curved guide faces, and

a straight chain support portion that extends from the imaginary boundary plane to a hollow region of the rigid chain part, wherein the straight chain support portion supports the rigid chain part by planar chain support side faces, which face the planar chain support faces.

5. The interlocking chain type forward and backward actuating device according to claim 4 , wherein the planar chain support side face extends from the imaginary boundary plane toward the opening for a distance equal to or longer than the pin-to-pin distance between the pair of front and rear connecting pins.

6. The interlocking chain type forward and backward actuating device according to claim 1 wherein

the interlocking chains are composed of a plurality of rows by coupling pairs of the hook-shaped inner tooth plates and pairs of the hook-shaped outer tooth plates in the chain width direction,

the rows include a supported row that comes into contact with the planar chain support face and an engagement row different from the supported row, and

the drive sprocket engages with the engagement row.

7. The interlocking chain type forward and backward actuating device according to claim 1 , wherein the connecting pins are guided by the chain guide grooves while projecting to the outside from plate faces of the hook-shaped outer tooth plates.