Linear motion devices that may include a band configured to be helically interlinked into a tube, where the band includes a plurality of protrusions and a plurality of recesses that engage the plurality of protrusions to link the band with itself. The linear motion devices also include a sliding guide configured to link and unlink the band, where the sliding guide includes an outer layer, an inner layer, and a ramp between the outer and inner layers having a helical incline to support a bottom portion of the band. The linear motion devices include a driving mechanism that is in contact with the band, the driving mechanism configured to move the band through the sliding guide up the helical incline to link the band, thereby extending the tube, and to move the band through the sliding guide down the helical incline to unlink the band, thereby retracting the tube.

The invention provides an extendible member (10) which is configurable between a coiled form (11) and an extended form (12). The extendible member (10) comprises: a primary member (14) comprising a sheet of material resiliently biased in a slit tube form, wherein the slit tube can be opened out at the slit to assume an open form in which it has a flattened cross section; at least one resilient secondary member (15) having first and second connections to the primary member (14) at respective different circumferential positions on the primary member (14), wherein in the extended form, the primary member (14) is in its slit tube form and the resiliency of the secondary member (15) causes at least part of the secondary member (15) to displace towards the slit in the primary member (14) to provide torsional and axial stiffness to the primary member (14), and wherein in the coiled form (11), the primary member (14) is in its open form and the secondary member (15) conforms to the flattened cross section of the primary member (149) so that primary and secondary member can be co-coiled. Corresponding methods are also provided.

The invention provides an extendible member (10) which is configurable between a coiled form (11) and an extended form (12). The extendible member (10) comprises: a primary member (14) comprising a sheet of material resiliently biased in a slit tube form, wherein the slit tube can be opened out at the slit to assume an open form in which it has a flattened cross section; at least one resilient secondary member (15) having first and second connections to the primary member (14) at respective different circumferential positions on the primary member (14), wherein in the extended form, the primary member (14) is in its slit tube form and the resiliency of the secondary member (15) causes at least part of the secondary member (15) to displace towards the slit in the primary member (14) to provide torsional and axial stiffness to the primary member (14), and wherein in the coiled form (11), the primary member (14) is in its open form and the secondary member (15) conforms to the flattened cross section of the primary member (149) so that primary and secondary member can be co-coiled. Corresponding methods are also provided.

The spiral advance/retreat actuation device includes a first strip material, a second strip material, an inner guide member as a strip material guide unit, an outer cylindrical wall, and a strip material storage container. The strip material storage container includes a first storage chamber that spirally stores a first strip material that has transitioned from a cylindrical configuration state to a separated state, and a second storage chamber that spirally stores a second strip material that has transitioned from a cylindrical configuration state to a separated state. The inner bottom surface of the first storage chamber and the inner bottom surface of the second storage chamber are sloped so as to descend as they move away from the axis.

The invention provides an extendible member which is configurable between a coiled form and an extended form. The extendible member comprises: a primary member comprising a sheet of material resiliently biased in a slit tube form, wherein the slit tube can be opened out at the slit to assume an open form in which it has a flattened cross section; at least one resilient secondary member having first and second connections to the primary member at respective different circumferential positions on the primary member, wherein in the extended form, the primary member is in its slit tube form and the resiliency of the secondary member causes at least part of the secondary member to displace towards the slit in the primary member to provide torsional and axial stiffness to the primary member, and wherein in the coiled form, the primary member is in its open form and the secondary member conforms to the flattened cross section of the primary member so that primary and secondary member can be co-coiled. Corresponding methods are also provided.

Linear motion devices that may include a band configured to be helically interlinked into a tube, where the band includes a plurality of protrusions and a plurality of recesses that engage the plurality of protrusions to link the band with itself. The linear motion devices also include a sliding guide configured to link and unlink the band, where the sliding guide includes an outer layer, an inner layer, and a ramp between the outer and inner layers having a helical incline to support a bottom portion of the band. The linear motion devices include a driving mechanism that is in contact with the band, the driving mechanism configured to move the band through the sliding guide up the helical incline to link the band, thereby extending the tube, and to move the band through the sliding guide down the helical incline to unlink the band, thereby retracting the tube.