US 5,310,356 AGranted

Transmission device used between two relatively rotatable components

AssigneeFurukawa Electric Co., Ltd.

InventorsKen Obata, Seiichi Ueno, Masahiro Hasegawa

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Abstract

A transmission device is equipped with a flat cable (11) which has a winding direction reversal section (11a) at the middle, and three dummy cables (21A through 21C) which are wrapped over the flat cable, the winding direction reversal sections (11a and 21a through 21c) of the flat cable and dummy cables being arranged in the circumferential direction at approximately equal intervals. The winding direction reversal sections which produce elastic reaction forces are distributed in the circumferential direction at approximately equal intervals, and hence the slack of the flat cable is suppressed when an inner case or an outer case performs reciprocal rotation, thus securely preventing troubles caused by the slack in the flat cable, whereby the possible case revolution number can be increased with a shorter flat cable, and the operation stability of the transmission device can be improved.

Claims19

Dependent claims

A transmission device comprising:

an inner case and an outer case which are rotatable relative to each other, and which are coupled together to define a space therebetween for receiving a transmission medium which is spirally wound and housed in said space defined by said inner case and said outer case;
a plurality of flexible cables provided in said space defined by said inner case and said outer case;
said plurality of flexible cables including at least one spirally wound transmission cable serving as said spirally wound transmission medium;
each of said plurality of flexible cables having inner and outer ends fixed to said inner case and to said outer case, respectively;
each of said plurality of flexible cables having inner and outer end sections, said inner and outer end sections normally extending in opposite directions from each other circumferentially around said inner and outer case, so that a direction reversal section at which cable movement reverses is formed in said space defined by said inner and outer cases;
said direction reversal sections of said plurality of flexible cables being spaced at mutually equal angular intervals circumferentially around the whole circumferential extent of said inner and outer cases;
and
each of said direction reversal sections generating an elastic reaction force for pressing the inner end section of at least one counterpart of said plurality of flexible cables, and also generating an elastic reaction force for pressing the outer end section of at least one counterpart of said plurality of flexible cables.

5 more elements

A transmission device comprising:

an inner case and an outer case which are rotatable relative to each other, and which are coupled together to define a space therebetween for receiving a transmission medium which is spirally wound and housed in said space defined by said inner case and said outer case;
a plurality of flexible cables provided in said space defined by said inner case and said outer case;
said plurality of flexible cables including at least one spirally wound transmission cable serving as said spirally wound transmission medium;
each of said plurality of flexible cables having inner and outer ends fixed to said inner case and to said outer case, respectively;
each of said plurality of flexible cables having inner and outer end sections, said inner and outer end sections normally extending in opposite directions from each other circumferentially around said inner and outer cases, so that a direction reversal section at which cable movement reverses is formed in said space defined by said inner and outer cases;
said direction reversal sections of said plurality of flexible cables being spaced at mutually equal angular intervals circumferentially around the whole circumferential extent of said inner and outer cases;
and wherein:
said inner case has a drum section;
said outer case has a cylindrical section which is provided coaxially with the drum section of said inner case;
and
said plurality of flexible cables are arranged so that their respective inner end sections are wrapped around the drum section of said inner case so as to overlap one another, and so that their outer end sections extend circumferentially along an inner surface of said cylindrical section of said outer case so as to overlap one another, as said inner and outer cases rotate relative to each other;
said drum section of said inner case has a plurality of inner slits therein, through which said inner ends of said plurality of flexible cables are passed;
and
said cylindrical section of said outer case has a plurality of outer slits therein, through which said outer ends of said plurality of flexible cables are passed.

11 more elements

A transmission device comprising:

an inner case and an outer case which are rotatable relative to each other, and which are coupled together to define a space therebetween for receiving a transmission medium which is spirally wound and housed in said space defined by said inner case and said outer case;
a plurality of flexible cables provided in said space defined by said inner case and said outer case;
said plurality of flexible cables including at least one spirally wound transmission cable serving as said spirally wound transmission medium;
each of said plurality of flexible cables having inner and outer ends fixed to said inner case and to said outer case, respectively;
each of said plurality of flexible cables having inner and outer end sections, said inner and outer end sections normally extending in opposite directions from each other circumferentially around said inner and outer cases, so that a direction reversal section at which cable movement reverses is formed in said space defined by said inner and outer cases;
said direction reversal sections of said plurality of flexible cables being spaced at intervals circumferentially around said inner and outer cases;
and wherein:
said inner case has a drum section;
said outer case has a cylindrical section which is provided coaxially with the drum section of said inner case;
and
said plurality of flexible cables are arranged so that their respective inner end sections are wrapped around the drum section of said inner case so as to overlap one another, and so that their outer end sections extend circumferentially along an inner surface of said cylindrical section of said outer case so as to overlap one another, as said inner and outer cases rotate relative to each other;
said drum section of said inner case has a plurality of inner slits therein, through which said inner ends of said plurality of flexible cables are passed;
and
said cylindrical section of said outer case has a plurality of outer slits therein, through which said outer ends of said plurality of flexible cables are passed;
and
wherein grooves for receiving bent parts of the cables are formed in the vicinity of those areas where said slits are formed in said inner case drum section and said outer case cylindrical section, said bent parts being formed at said inner ends or said outer ends of said cables when said inner and outer cases begin further relative rotation from their ultimate relative rotation position, or from their neutral relative rotation position.

13 more elements

Dependencies are inferred from the claim text.