Abstract: An orthopaedic surgical instrument includes a patella trial and drill guide that may be used to both perform a surgical trial of the patellofemoral joint and guide the surgeon in drilling a number of anchor holes in the patella of the patient.

Abstract: A symmetrical open-end wrench having rear side corners adjacent open ends of the throat of the wrench and opposing jaws defining an opening for receiving a fastener, the jaws having parallel planar section, and continuously diverging surfaces with fastener-engaging irregularities merging with the respective rear side corners in a smooth transition.

Abstract: An asymmetrical wrench and fastener system comprising radially extending splines having opposing surfaces whose inner ends are inclined by different amounts with respect to a radius intersecting the respective inner ends to alter the torque between the tightening and loosening directions. This configuration makes it either easier or harder to loosen the fastener than it was to tighten it, depending on the amount the opposing surfaces of the splines are inclined.

Abstract: A symmetrical open-end wrench having rear side corners adjacent open ends of the throat of the wrench and opposing jaws defining an opening for receiving a fastener, the jaws having parallel planar section, and continuously diverging surfaces with fastener-engaging irregularities merging with the respective rear side corners in a smooth transition.

Abstract: Open-end symmetrical wrenches retain fasteners fully seated in the jaws of the wrench. The jaws have fastener-engaging surfaces with substantially planar and parallel sections that extend past the front side corners of the fastener when it is fully seated in the wrench and serrated diverging sections extending outwardly and rearwardly from these planar sections. The serrated diverging section may be arcuate or a slightly inclined. Both types of diverging section are designed to reduce slipping and are connected to rear corners of the fastener-engaging cavity that are designed and positioned to avoid contact with the rear side corners of the fastener. Arcuate rear side corners of the wrench cavity avoid contact with the rear side corners of the fastener and avoid stress concentration points. The throat that connects the corners has two gentle curves or flat surfaces leading to a central arc. This modified “U” design provides more metal in the throat of the wrench, which stiffens the jaws.

Abstract: An asymmetrical wrench and fastener system comprising radially extending splines having opposing surfaces whose inner ends are inclined by different amounts with respect to a radius intersecting the respective inner ends to alter the torque between the tightening and loosening directions. This configuration makes it either easier or harder to loosen the fastener than it was to tighten it, depending on the amount the opposing surfaces of the splines are inclined.

Abstract: Open-end symmetrical wrenches retain fasteners fully seated in the jaws of the wrench. The jaws have fastener-engaging surfaces with substantially planar and parallel sections that extend past the front side corners of the fastener when it is fully seated in the wrench and serrated diverging sections extending outwardly and rearwardly from these planar sections. The serrated diverging section may be arcuate or a slightly inclined. Both types of diverging section are designed to reduce slipping and are connected to rear corners of the fastener-engaging cavity that are designed and positioned to avoid contact with the rear side corners of the fastener. Arcuate rear side corners of the wrench cavity avoid contact with the rear side corners of the fastener and avoid stress concentration points. The throat that connects the corners has two gentle curves or flat surfaces leading to a central arc. This modified “U” design provides more metal in the throat of the wrench, which stiffens the jaws.

Abstract: An asymmetrical wrench and fastener system comprising radially extending splines having opposing surfaces whose inner ends are inclined by different amounts with respect to a radius intersecting the respective inner ends to alter the torque between the tightening and loosening directions. This configuration makes it either easier or harder to loosen the fastener than it was to tighten it, depending on the amount the opposing surfaces of the splines are inclined.

Abstract: A high torque wrenching system having a wrench with asymmetrical torque transmission capability. The wrench includes a plurality of protuberances and a plurality of recesses around a central axis. The fastener also includes a plurality of protuberances and recesses around the central axis for mating with the wrench. The protuberances and recesses form a saw tooth shape. Each tooth or protuberance is formed by a first wrenching surface for loosening the fastener and a second wrenching surface for tightening the fastener. The wrenching surface carrying the loosening load is at a much smaller angle with respect to a radial vector extending from the wrench's central axis than the wrenching surface carrying the tightening load. The result is that the loosening torque vector will have a much greater moment arm.

Abstract: A high torque wrenching system is provided having a wrench with asymmetrical torque transmission capability. The wrench includes a plurality of protuberances and a plurality of recesses around a central axis. The fastener also includes a plurality of protuberances and recesses around the central axis for mating with the wrench. The protuberances and recesses form a saw tooth shape. Each tooth or protuberance is formed by a first wrenching surface for loosening the fastener and a second wrenching surface for tightening the fastener. The wrenching surface carrying the loosening load will be at a much smaller angle, with respect to a radial vector extending from the wrench's central axis, than the wrenching surface carrying the tightening load. The result is that the loosening torque vector will have a much greater moment arm.

Abstract: Disclosed is an asymmetrical fastening system comprising (1) a fastener having asymmetrical loosening surfaces and tightening surfaces formed in a single fastening periphery, and (2) a wrench comprising asymmetrical loosening surfaces and tightening surfaces formed in a single fastening periphery, that engage, respectively, the loosening surfaces and tightening surfaces of the fastener. When the wrench engages the fastener and force is applied to the wrench the torque to failure of the system in the loosening direction is greater than the torque to failure in the tightening direction.

Abstract: An asymmetrical wrench and fastener system comprising radially extending splines having opposing surfaces whose inner ends are inclined by different amounts with respect to a radius intersecting the respective inner ends to alter the torque between the tightening and loosening directions. This configuration makes it either easier or harder to loosen the fastener than it was to tighten it, depending on the amount the opposing surfaces of the splines are inclined.

Abstract: Open wrenches retain fasteners fully seated in the jaws of the wrench. The jaws have fastener-engaging surfaces with substantially planar and parallel sections that extend past the front side corners of the fastener when it is fully seated in the wrench, and serrated diverging sections extending outwardly and rearwardly from these planar sections. The serrated diverging section may be arcuate or a slightly inclined. Both types of diverging section are designed to reduce slipping, and are connected to rear corners of the fastener-engaging cavity that are designed and positioned to avoid contact with the rear side corners of the fastener. Arcuate rear side corners of the wrench cavity avoid contact with the rear side corners of the fastener, and avoids stress concentration points. The throat that connects the corners has two gentle curves or flat surfaces leading to a central arc. This modified “U” design provide more metal in the throat of the wrench, which stiffens the jaws.

Abstract: A double-ended flex-handle wrench having a pivotable tool head at each end thereof, the tool head having a locking-type retaining device for locking a gripping member to the tool head.

Abstract: A wrench for turning a fastener nut having a central axis and an even-numbered plurality of flat bounding surfaces parallel to the fastener access wherein diametrically opposite pairs of surfaces are parallel to each other and the bounding surfaces intersect in adjacent pairs to form fastener corners. The wrench includes a fastener nut socket defined by a central socket axis. The socket includes a plurality of uniformly spaced peripherally and radially disposed sides and a plurality of uniformly spaced fastener corner clearance recesses disposed between sides. Each side includes a planar surface and a pair of complimentary surfaces, wherein a complimentary surface diverges outwardly from each end of the planar surface at an angle of approximately three degrees (3.degree.). The planar surface has a length approximately equal to 0.35 times (.times.) the minor diameter of the fastener nut to be driven.

Abstract: A wrench for turning a fastener nut having a central axis and an even-numbered plurality of flat bounding surfaces parallel to the central axis with diametrically opposite pairs being parallel to each other. The wrench includes a fastener nut engaging socket defined about a central socket axis by a plurality of uniformly spaced peripherally and radially disposed protuberances and plurality of uniformly spaced corner recesses disposed between the protuberances. Each protuberance includes outwardly diverging angularly related straight engaging surfaces for registry with the flat surfaces on the fastener nut. Each recess is comprised of a first arcuate surface tangential to a circle about the central axis of the socket and transitional surfaces converging from the adjacent protuberances toward the first arcuate surface.

Abstract: A wrench for turning a fastener nut having a central axis and an even-numbered plurality of flat bounding surfaces parallel to the central axis with diametrically opposite pairs being parallel to each other. The wrench includes a fastener nut engaging socket defined about a central socket axis by a plurality of uniformly spaced peripherally and radially disposed protuberances and plurality of uniformly spaced corner recesses disposed between the protuberances. Each protuberance includes side-by-side angularly related straight engaging surfaces at substantially 142.degree. outside obtuse angles to each other for registry with the flat surfaces on the fastener nut and complementary side surfaces outwardly diverging from said engagement surfaces. Each recess is comprised of a first arcuate surface tangential to a circle about the central axis of the socket and transitional surfaces converging from the side surfaces of adjacent protuberances toward the first arcuate surface.