Abstract: A golf club head has a body defining a ball striking face. The body further has a first leg extending away from the ball striking face and a second leg extending away from the ball striking face wherein a void is defined between the first leg and the second leg. The body further defines a crown that extends over the void.

Abstract: Golf performance and equipment characteristics may be determined by analyzing the impact between a golf ball and an impacting surface. In some examples, the impacting surface may be a golf club face. The impact between the golf ball and the surface may be measured based on sound and/or motion sensors (e.g., gyroscopes, accelerometers, etc.). Based on motion and/or sound data, various equipment-related information including golf ball compression, club head speed and impact location may be derived. Such information and/or other types of data may be conveyed to a user to help improve performance, aid in selecting golf equipment and/or to insure quality of golfing products.

Abstract: A ball striking device, such as a golf club head, has a face with a striking surface configured for striking a ball, and a channel extending across a portion of the sole. The channel extends across a portion of the sole in a heel to toe direction, wherein the channel is recessed from adjacent surfaces of the sole and has a depth of recession from the adjacent surfaces of the sole, wherein the channel comprises a center portion extending across a center of the sole, a heel portion extending from a heel end of the center portion toward the heel, and a toe portion extending from a toe end of the center portion toward the toe, wherein the width of the center portion of the channel is substantially constant, and the width of the channel at the heel and toe portions increases from the heel end of the center portion toward the heel and from the toe end of the center portion toward the toe.

Abstract: A ball striking device, such as a golf club head, has a face with a striking surface configured for striking a ball, a channel extending across a portion of the sole, wherein the channel is recessed from adjacent surfaces of the sole, and/or a void defined on the sole of the body, wherein the channel has width defined in a front to rear direction and a depth of recession from the adjacent surfaces of the sole at a vertical plane passing through the face center, wherein a ratio of the width to the depth is about 0.8:1 to 1.2:1.

Abstract: A ball striking device, such as a golf club head, has a face with a striking surface configured for striking a ball, a channel extending across a portion of the sole, wherein the channel is recessed from adjacent surfaces of the sole, a void defined on the sole of the body, at least one external rib located in the void and extending downward from the void, and/or at least one internal rib is connected to an internal portion of a golf club head body and extending into an internal cavity, and wherein the golf club head has a first natural frequency greater than 3000 Hz.

Abstract: A ball striking device, such as a golf club head, has a face with a striking surface configured for striking a ball, a channel extending across a portion of the sole, wherein the channel is recessed from adjacent surfaces of the sole and/or a void defined on the sole of the body. The channel has width defined in a front to rear direction and a depth of recession from the adjacent surfaces of the sole at a vertical plane passing through the face center, wherein a ratio of the width to the depth is approximately 3.5:1 to 4.5:1.

Abstract: A ball striking device, such as a golf club head, has a face with a striking surface configured for striking a ball, a body connected to the face and extending rearwardly from the face, the body having a crown, a sole, a heel, and a toe, a void defined on the sole of the body, and at least one external rib is positioned within the void. A ratio of cross-sectional area moment of inertia Ix-x with and without the at least one external rib is greater than a ratio of cross-sectional area moment of inertia Iz-z with and without the at least one external rib when measured at a location defined by a distance from a forward most edge of the golf club head measuring 60 percent of a breadth dimension.

Abstract: A ball striking device, such as a golf club head, has a face with a striking surface configured for striking a ball and a channel extending across a portion of the sole. The channel may be recessed from the sole and have a depth, wherein the channel comprises a center portion extending across a center of the sole, a heel portion extending from a heel end of the center portion toward the heel, and a toe portion extending from a toe end of the center portion toward the toe. The channel may have a width defined between a front edge and a rear edge, and a cross-sectional shape, wherein the cross-sectional shape of the center portion of the channel is substantially semi-circular, and wherein the cross-sectional shape of the channel is different at the heel and toe portions than at the center portion.

Abstract: A ball striking device, such as a golf club head, has a face with a striking surface configured for striking a ball, a channel extending across a portion of the sole, wherein the channel is recessed from adjacent surfaces of the sole, a void defined on the sole of the body, and/or at least one external rib connected to the cover and extending downward from the cover. The at least one external rib may include a first external rib and a second external rib wherein each external rib is connected to the cover and extends downward from the cover, such that the external ribs are positioned within the void.

Abstract: A ball striking device, such as a golf club head, has a face with a striking surface configured for striking a ball and a channel extending across a portion of the sole. The channel may be recessed from adjacent surfaces of the sole and have a depth of recession from the adjacent surfaces of the sole, wherein the channel comprises a center portion extending across a center of the sole, a heel portion extending from a heel end of the center portion toward the heel, and a toe portion extending from a toe end of the center portion toward the toe, wherein the width and the depth of the center portion of the channel are substantially constant, and wherein the depth of the channel is greater at the heel and toe portions than at the center portion.

Abstract: A ball striking device, such as a golf club head, has a face with a striking surface configured for striking a ball and an elongated channel extending across a portion of the sole in a heel to toe direction. The channel is recessed from adjacent surfaces of the sole. The channel may have a width defined in a front to rear direction and a depth of recession from the adjacent surfaces of the sole, wherein the channel comprises a center portion extending across a center of the sole, a heel portion extending from a heel end of the center portion toward the heel, and a toe portion extending from a toe end of the center portion toward the toe. The channel may have a wall thickness that is greater in the center portion of the channel than in at least one of the heel and toe portions.

Abstract: A ball striking device has a head with a body member having a face having a striking surface configured for striking a ball, a crown portion and a sole portion connected to the face and extending rearward from the face, where the body member has a void extending inwardly from a rear periphery of the body member, and a rear member connected to the body member and received within the void, such that the rear member forms portions of a crown and a sole of the head. A connection member connects the rear member to the body member to form a joint between the rear member and the body member. A resilient member separates the rear member from the body member, and the resilient member engages the rear member and the body member within the void and is configured to transfer momentum between the rear member and the body member.

Abstract: A golf club head has a body defining a ball striking face. The body further has a first leg extending away from the ball striking face and a second leg extending away from the ball striking face wherein a void is defined between the first leg and the second leg. The body further defines a cover that extends over the void. The golf club head may further have support structures and adjustable weight members.

Abstract: A ball striking device, such as a golf club head, has a face with a striking surface configured for striking a ball; a channel extending across a portion of the sole, wherein the channel is recessed from adjacent surfaces of the sole; a void defined on the sole of the body and a cover defining a top of the void; and a first external rib and a second external rib wherein each external rib is connected to the cover and extends downward from the cover, such that the external ribs are positioned within the void. The channel has a width and a depth, wherein the channel comprises a center portion, a heel portion, and a toe portion, and wherein at least one or both of the width and the depth of the channel is greater at the heel portion and the toe portion than at the center portion.

Abstract: A golf club head has a body defining a ball striking face. The body further has a first leg extending away from the ball striking face and a second leg extending away from the ball striking face wherein a void is defined between the first leg and the second leg. The body further defines a crown that extends over the void.

Abstract: A golf club head has a body defining a ball striking face. The body further has a first leg extending away from the ball striking face and a second leg extending away from the ball striking face wherein a void is defined between the first leg and the second leg. The body further defines a crown that extends over the void.

Abstract: Methods and systems are provided for head mounted display (HMD) implementations. One example implementation, a HMD includes a circuit for communicating with a computing system that processes multimedia content for display in the HMD. Further included is a front unit of the HMD that has a screen for displaying multimedia content, and the front unit has a set of LEDs. The HMD includes an accelerometer and gyroscope disposed in the front unit of the HMD. A rear section of the HMD is provided having a set of LEDs. A headband connecting the front unit to the rear section is included, such that adjustment of the headband changes a separation distance between at least one of the set of LEDs of the front unit and at least one of the set of LEDs of the rear section. Wherein calibration of the separation distance is performed from time to time to produce and estimated separation distance for tracking of the HMD during use.

Abstract: A ball striking device, such as a golf club head, includes a face having a ball striking surface configured for striking a ball and a body connected to the face and extending rearwardly from the face. The body has an impact-influencing structure in the form of a channel positioned on at least one surface of the body. A majority of a force generated by impact with a ball is absorbed by the impact-influencing structure, and a majority of a response force generated by the head upon impact with the ball is generated by the impact-influencing structure. The face may have increased stiffness as compared to existing faces, and may include a stiffening structure to create the increased stiffness, such as a porous or cellular stiffening structure.

Abstract: A flexible mounting base to hold a sensor at an infusion site, the sensor being a removable in vivo sensor for monitoring analyte concentration level in a patient, such as blood glucose (BG) level. The mounting base comprises a flexible adhesive that anchors the flexible sensor set at an infusion site to provide stability for the sensor set in a convenient and comfortable manner. Placement of the mounting base onto the patient's skin causes the insertion needle to pierce the skin for transcutaneous placement of the cannula with the sensor therein. The insertion needle can then be withdrawn to leave the cannula and sensor at the selected insertion position, with the distal segment of the sensor being exposed to patient extracellular fluid via apertures formed in the cannula.

Abstract: Golf club heads include an iron type golf club head body having a rear surface (e.g., a perimeter weighting member) that defines a first weight receiving portion, and a weight member is mounted in the first weight receiving portion. The club head body further defines a second weight receiving portion independent of the first weight receiving portion, and a second weight member is removably engaged with the golf club head body at this second weight receiving portion. The weight members may be interchangeably mounted in the two weight receiving portions to thereby allow selective placement of the center of gravity characteristics of the club head body. Golf clubs including these club heads and methods of making such golf club and golf club heads also are described.