Automatic compression-distraction apparatus

Claim 2

A surgical orthopedic apparatus, comprising: support members; pillars serving to connect the support members; pins passing through bone and attached to said support members; a drive designed to adjust the relative position of said support members, said drive including: a housing secured on said pillars; a lead screw mounted in a pillar and connected by its one end to said support member; a ratchet wheel mounted in said housing and interacting with said lead screw; a pawl connected with teeth of said ratchet wheel; a load-bearing element coupled by its one end to said pawl while its other end is rigidly attached to said housing; said load-bearing element being essentially a tie-rod manufactured from an alloy possessing plastic memory; a resilient member fashioned as a spring with its one end attached to said housing and the other end interacting with said load-bearing element; an adjusting member arranged in said housing, connected by its one end to said tie-rod and designed for setting the force of tensioning said tie-rod.

Claim 3

An apparatus as claimed in claim 1, wherein said resilient member is manufactured from an alloy possessing plastic memory and featuring the temperature of inverse martensite transformation of about 100°-150° C. below that of the material of the load-bearing element.

Claim 4

An apparatus as claimed in claim 1, wherein said tie-rod is fashioned as a thin-walled tube while the electric heater is positioned thereinside.

Claim 5

An apparatus as claimed in claim 1, wherein said tie-rod is fashioned as a wire.

Claim 6

A surgical orthopedic apparatus, comprising: support members; pillars serving to connect said support members; pins passing through bone and attached to said support members; at least one pin passing through a fragment chipped off the bone and attached to a lead screw designed to adjust the position of the said pin; a drive designed to adjust the relative position of said pin and said bone fragment, attached to said support member and including: a housing mounted on at least one said support member; a ratchet wheel mounted in said housing and interacting with said lead screw; a pawl connected with teeth of said ratchet wheel; a load-bearing element coupled by its one end to said pawl and by its other end to said housing, said load-bearing element being essentially a tie-rod manufactured from an alloy possessing plastic memory; a resilient member fashioned as a spring with its one end attached to said housing and the other end interacting with said load-bearing element; an electric heater mounted in said housing and interacting with said load-bearing element; an adjusting member arranged in said housing, connected by its one end to said tie-rod and designed for setting the force of tensioning said tie-rod.

Claim 7

A surgical orthopedic apparatus, comprising: support members; pillars serving to connect said support members; pins passing through bone and attached to said support members; at least one pin passing through a fragment chipped off the bone and attached to a lead screw designed to adjust the position of the said pin; a drive designed to adjust the relative position of said pin and said bone fragment, attached to said support member and including: a housing mounted on at least one said support member; a ratchet wheel mounted in said housing and interacting with said lead screw; a pawl connected with teeth of said ratchet wheel; a load-bearing element coupled by its one end to said pawl and by its other end to said housing, said load-bearing element being essentially a tie-rod manufactured from an alloy possessing plastic memory; a resilient member fashioned as a spring with its one end attached to said housing and the other end interacting with said load-bearing element; an electric heater mounted in said housing and interacting with said load-bearing element; an adjusting member arranged in said housing, connected by its one end to said tie-rod and designed for setting the force of tensioning said tie-rod.

Claim 8

An apparatus as claimed in claim 5, wherein said pawl is fashioned as a resilient clamp whose end is rigidly attached to said tie-rod while the middle portion of said clamp interacts with teeth of said ratchet wheel.

Claim 9

An apparatus as claimed in claim 5, wherein said tie-rod is coupled by its one end to said pawl by means of a lever having a bigger arm and a smaller arm, the smaller arm of said layer being connected to said tie-rod.

Claim 10

An apparatus as claimed in claim 5, wherein said lever and said tie-rod are positioned in a plane normal to the plane of said ratchet wheel.

Claim 11

A surgical orthopedic apparatus, comprising: support members; at least one lead screw designed to adjust the relative position of said support members; pins passing through bone and attached to said support members; a drive designed to adjust the relative position of the support members and attached to one of the latter, said drive including: a housing mounted on at least one of said support members; a ratchet wheel mounted in said housing and interacting with said lead screw; a pawl connected with teeth of said ratchet wheel; a load-bearing element coupled by its one end to said pawl and by its other end to said housing, said load-bearing element being essentially a tie-rod manufactured from an alloy possessing plastic memory; a resilient member fashioned as a spring comopressed within said housing between one of end walls thereof and said pawl, with said tie-rod being positioned inside said spring coaxially therewith; an electric heater mounted in said housing and interacting with said tie-rod; an adjusting member arranged in said housing and designed for setting the force of tensioning said tie-rod and said spring.

Claim 12

A surgical orthopedic apparatus, comprising: support members; at least one lead screw designed to adjust the relative position of said support members; pins passing through bone and attached to said support members; a drive designed to adjust the relative position of the support members and attached to one of the latter, said drive including: a housing mounted on at least one of said support members; a ratchet wheel mounted in said housing and interacting with said lead screw; a pawl connected with teeth of said ratchet wheel; a load-bearing element coupled by its one end to said pawl and by its other end to said housing, said load-bearing element being essentially a tie-rod manufactured from an alloy possessing plastic memory; a resilient member fashioned as a spring comopressed within said housing between one of end walls thereof and said pawl, with said tie-rod being positioned inside said spring coaxially therewith; an electric heater mounted in said housing and interacting with said tie-rod; an adjusting member arranged in said housing and designed for setting the force of tensioning said tie-rod and said spring.

Claim 13

An apparatus as claimed in claim 9, wherein said lead screw is provided with a longitudinal flat and with a lock screw mounted immovably relative to said housing.