Patents Assigned to Mit AB
-
Patent number: 5549380Abstract: A mixing device for mixing at least two substances, preferably a liquid monomer and a pulverulent polymer, for manufacturing bone cement. The two substances (16, 17) are mixed in a mixing space (9) in a mixing container (1), preferably in partial vacuum. The substances are provided separated from each other in a container (1, 18, respectively) for each substance. A mixing device (6) is provided in the mixing space (9) for mixing the two substances (16,17) therein. An opener (26), defined preferably by the mixing device (6), is provided for establishing at least one connection (27) between the separately provided substances (16, 17) and for bringing the substances in contact with each other for mixing. During opening of the connection (27) between the substances (16, 17) in the mixing space (9), the vacuum sucks one of the substances (16), preferably the liquid monomer, through the connection (27) to the other substance (17), preferably the pulverulent polymer.Type: GrantFiled: March 3, 1995Date of Patent: August 27, 1996Assignee: MIT ABInventors: Lars .ANG. A. Lidgren, Hans J. Bauer
-
Patent number: 5501520Abstract: A mixing device for producing reduced porosity bone cement. The device having a movable member (6), preferably a movable piston, which is adapted to press out or discharge bone cement (2) from the mixing device (1). The piston is fixedly mounted in the mixing device. The piston maintains its position when bone cement (2) is mixed in a mixing space in the mixing device. The mixing device is under a vacuum during mixing. After mixing, the piston is released such that it can be drawn into the mixing device (1) toward a discharge opening (13) by a vacuum prevailing in the mixing device (1). The moving piston is used for collecting clumps of bone cement (2) in the mixing device (1) adjacent to the discharge opening (13). By collecting the clumps of bone cement by the moving piston (6) under a vacuum, the porosity of the bone cement (2) is reduced.Type: GrantFiled: April 26, 1994Date of Patent: March 26, 1996Assignee: MIT ABInventors: Lars A. Lidgren, Lars G. Dahl
-
Patent number: 5328262Abstract: A method for producing bone cement by mixing components forming part thereof, whereby mixing occurs in vacuum in a mixing device (1) and whereby ready-mixed bone cement (2) is collected in the mixing device (1) before it is ejected or discharged therefrom. For reducing the volume of porosity of the pores formed in the bone cement (2) during collection, the bone cement (2) is collected in vacuum to provide vacuum in those pores in the bone cement (2) which are formed during collection, whereby the volume of porosity in the bone cement (2) is reduced when the bone cement is subjected to atmospheric pressure after collection.Type: GrantFiled: February 3, 1993Date of Patent: July 12, 1994Assignee: Mit ABInventors: Lars A. A. Lidgren, Lars G. Dahl
-
Patent number: 5087261Abstract: A saw-blade for sawing living human bone during surgical operations, the saw-blade (1) presenting on at least one side (10) at least two saw portions (8, 9) and said saw-blade (1) having at least one inner space (14) through which coolant (18) is adapted to flow for cooling the saw-blade (1) during sawing. For efficient direct cooling of the saw portions (8, 9) and continuous cleaning thereof during sawing, the space (14) extends up to the two saw portion (8, 9) and is open between them in order, on one hand, to conduct coolant (18) to the saw portions (8, 9) for cooling them, and, on the other hand, to cause coolant (18) to emerge between the saw portions (8, 9) for carrying off bone residues or other saw residues in a direction away from the saw portions (8, 9).Type: GrantFiled: September 20, 1990Date of Patent: February 11, 1992Assignee: MIT ABInventors: Leif E. S. H. Ryd, Anders O. Bertilsson-Lindstrand, Soren Toksvik-Larsen
-
Patent number: 4758096Abstract: This invention relates to an apparatus for mixing bone cement in vacuum, in which mixing takes place in a container (11) from which ready-mixed bone cement (4) is adapted to be ejected by means of a piston (2) in the mixing container (1) for supplying the bone cement (4) to a hollow in the bone wherein a prosthesis is to be fixed by means of the bone cement (4), and the mixing container (1) is connectable to a vacuum device which is adapted to generate vacuum in the mixing container (1) during mixing.With a view to providing an apparatus of simple and compact design, which permits efficient retention of the mixing container during mixing, the vacuum device comprises a vacuum container (9) in which the mixing container (1) is adapted to be disposed in such a way that the mixing container spaces (3, 6) on both sides (5, 7) of the piston (2) communicate with the interior (10) of the vacuum container (9) whereby the same vacuum is obtained on both sides of the piston (2).Type: GrantFiled: December 8, 1986Date of Patent: July 19, 1988Assignee: Mit ABInventor: Kjell Gunnarsson
-
Patent number: 4721390Abstract: The present invention relates to a method for producing bone cement for fixing protheses, whereby the bone cement is manufactured by mixing various substances with each other to provide a setting mass which in set condition is adapted to fix prostheses at surrounding bone tissue. In order to prevent large amounts of air from being stirring into the mixture, mixing of said various substances occurs under vacuum. The invention also relates to a device for carrying out the method for producing bone cement for fixing prostheses, whereby the bone cement is manufactured by mixing various substances with each other to provide a setting mass which in set condition is adapted to fix protheses at surrounding bone tissue, and whereby the mixture is applied to the bone tissue by means of a feed device (20) from which the mixture (19) may be pressed out.Type: GrantFiled: October 17, 1985Date of Patent: January 26, 1988Assignee: Mit ABInventor: Lars A. A. Lidgren