Device for the injection of bone cement, comprising an overpressure locking system
Inventors
Bonnin, Freddy • Leonard, Alain
Assignees
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Publication Number
US-8876834-B2
Publication Date
2014-11-04
Expiration Date
Abstract
The invention relates to a device for the injection of a bone cement. The invention comprises a container provided with one end including an outlet and a second end that receives a piston. The piston is moved by means of an injection screw that projects from the container body and engages with gripping means comprising injection screw rotation means that can self-lock depending on the pressure exerted inside the container body, said rotation means comprising a handle which is provided with a passage that receives the injection screw and which is hinged thereto by means of a pair of male/female disks. One disk is known as the drive disk and moves integrally with the rotation movements of the handle, while the other disk is known as the driven disk, said drive disk coming into contact with the driven disk in response to a compressive force exerted on the distal part of the injection screw.
Core Innovation
The disclosed invention is a device for the injection of bone cement that includes a reservoir container receiving bone cement, with a first end comprising an outlet aperture for the injection of cement and a second end receiving a piston capable of performing longitudinal translational movements inside the body of the container. The piston is set in motion via an injection screw projecting from the body of the reservoir and engaging gripping means designed to be placed integrally in contact with the container. The injection screw projects from the container and is part of a rotatably driving system that controls piston movement.
The invention provides rotatably driving means for the injection screw that are capable of self-locking depending on the pressure inside the container body. A handle having a passage receives the injection screw and is articulated therewith via a pair of male/female disks, comprising a driving disk integral with the rotational movements of the handle and performing translational movements on the longitudinal axis of the passage, and a driven disk integral with the rotational movements of the injection screw.
The driving disk comes into contact with the driven disk under the effect of a compressive force exerted on the distal part of the injection screw, so that the coupling between the handle and the injection screw is maintained when the compressive force allows contact. When the internal pressure reaches a threshold associated with the self-locking behavior, the engagement is functionally prevented such that the injection handle rotates idly while the piston/injection screw is prevented from advancing, thereby avoiding overpressure and rupture and uncontrolled cement flow.
Claims Coverage
The document provides one independent claim with main inventive features that define a bone-cement injection device with a pressure-dependent self-locking rotational drive. Dependent claims refine the disk-compression coupling, adjust spring compression distance, specify gripping means with complementary screw threads, and add return-spring and locking/unlocking structures.
Pressure-dependent self-locking rotational drive for the injection screw
Means for rotatably driving the injection screw capable of self-locking depending on the pressure inside the container body.
Handle articulated with male/female disks for transmission of rotation
A handle having a passage receiving the injection screw and articulated therewith via a pair of male/female disks, where one disk is a driving disk integral with the rotational movements of the handle and performs translational movements on the longitudinal axis of the passage, and the other is a driven disk integral with the rotational movements of the injection screw.
Compressively actuated contact between driving disk and driven disk
The driving disk comes into contact with the driven disk under the effect of a compressive force exerted on the distal part of the injection screw.
Compression-spring driven disk contact
Two disks are brought into contact using a compression spring anchored at the distal part of an injection screw and contacting the driving disk directly or indirectly.
Clamping means for adjustable compression distance of the spring
The distal portion of an injection screw includes clamping means to adjust the compression distance of a spring.
Gripping means with complementary screw thread
Gripping means include a screw thread complementary to the screw thread on the injection screw.
Return spring coupling between driving part and gripping means
The driving part is connected to a return spring that contacts the gripping means.
Locking/unlocking ring and pin arrangement with return spring
Gripping means include a locking/unlocking ring and a pin that compresses a return spring.
Across the independent claim and its dependents, the core claim set centers on a handle-driven rotational mechanism using male/female driving and driven disks whose coupling is established by compressive force and is self-locking depending on internal container pressure, with refinements adding spring-compression coupling, adjustability, complementary screw-thread gripping means, and return-spring/locking structures.
Stated Advantages
Avoiding overpressure and rupture.
Preventing uncontrolled cement flow by preventing piston/injection screw advancement when self-locking engagement is functionally prevented.
Documented Applications
Not explicitly described in patent.
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