A system determines the frequency of grid signals corresponding to an electrical grid in real time. The system includes a transient detector that monitors a grid signal from a voltage meter or a current meter connected to the electrical grid. The system produces, in real time and at a sampling rate, a deviation signal indicative of a periodicity of the monitored grid signal. The system determines, over one or more cycles of the monitored grid signal, a measurement signal corresponding to the deviation signal. The system determines a frequency signal that corresponds a frequency estimation of the monitored signal by applying a frequency estimation when values of the measurement signal are less than a deviation threshold and maintaining the frequency signal at a constant value when values of the measured signal equal or exceeds the deviation threshold.

A protective shield is provided for use with headwear having a brim and wearable by a user. The protective shield includes an elongate suspension strap portion and a pair of attachment tabs engageable with the headwear and positioned such that the elongate suspension strap portion extends between the pair of attachment tabs. A protective portion is connected to the suspension strap portion and is configured to extend over the user's eyes, nose, and mouth when the protective shield is attached to the headwear. The suspension strap portion and the protective portion collectively define a slot sized to receive the brim of the headwear to facilitate engagement between the protective shield and the headwear.

A protective shield is provided for use with headwear having a brim and wearable by a user. The protective shield includes an elongate suspension strap portion and a pair of attachment tabs engageable with the headwear and positioned such that the elongate suspension strap portion extends between the pair of attachment tabs. A protective portion is connected to the suspension strap portion and is configured to extend over the user's eyes, nose, and mouth when the protective shield is attached to the headwear. The suspension strap portion and the protective portion collectively define a slot sized to receive the brim of the headwear to facilitate engagement between the protective shield and the headwear.

Sensor assisted head mounted displays for welding are disclosed. Disclosed example head mounted devices include an optical sensor, an augmented reality controller, a graphics processing unit, and a semi-transparent display. The optical sensor collects an image of a weld environment. The augmented reality controller determines a simulated object to be presented in a field of view, a position in the field of view, and a perspective of the simulated object in the field of view. The graphics processing unit renders the simulated object based on the perspective to represent the simulated object being present in the field of view and in the weld environment. The display presents the rendered simulated object within the field of view based on the position. At least a portion of the weld environment is observable through the display and the lens when the display is presenting the rendered simulated object.

A visor carrier assembly for a safety helmet, comprising: a visor; and an attachment device for attaching the visor to a safety helmet for use, the attachment device including a double-pivot mechanism attachable to each side of a safety helmet and configured to enable the visor to be selectively pivoted relative to said safety helmet, in use, between at least first, second and third visor positions, each double-pivot mechanism comprising an elongate arm, said elongate arm being coupled, by a first pivotal coupling at one end thereof, to a respective side region of the visor and coupled, by a second pivotal coupling at a longitudinally opposing second end thereof, to a fixed point, in use, at a respective side of said safety helmet, each pivotal coupling comprising a coupling member and a coupling region, each coupling member comprising a fixed elongate pin having rounded portions at each end, each coupling region comprising an aperture defining, along its inner edge, a first notch or aperture within which one of the rounded portions of a respective coupling member is received to define a fixed pivot point, and an arcuate guide wall with which the opposite rounded portion of said respective coupling member engages and having a plurality of ridges defining grooves or notches for receiving said opposite rounded portion as a respective pivotal coupling is pivoted about said fixed pivot point, each said groove or notch defining a respective said visor position, a visor carrier assembly for a safety helmet.

A system including a head-mounted device having a face shield; a respirator coupled to or embodied in the head mounted device; a light having a light intensity; a light detector, and a computing device communicatively coupled to the at least one light detector that receive from the light detector data indicting a type and intensity of light, and determine that the light matches a particular type of light and whether it exceeds a threshold, and on the basis of this determination, modifies the intensity of the light.

A protective helmet adapted to receive and protect a head of a wearer comprises: an outer shell shaped to protect the head of the wearer, with the outer shell defining a bottom opening and an internal cavity for receiving the head of the wearer; a headband and a suspension positioned within the internal cavity of the outer shell; and a visor rotatable between a retracted position within the outer shell to an extended position in front of a face of the wearer, wherein the visor simultaneously rotates about a first pivot axis and a second pivot axis as it moves between the retracted position and the extended position. The visor can also be readily removed from the protective helmet and easily replaced should it become damaged.

A protective helmet comprising a head mountable shell (10) and a transparent visor (24), the head mountable shell defining a rear portion and an opposing front portion (12) when oriented for use, the front portion being recessed, the helmet further comprising a cover portion (16) mountable over the recessed front portion so as to define a cavity, the transparent visor being pivotally mounted across the recessed front portion by means of a pair of pivot mechanisms (28), the pivot mechanisms being located at opposing sides of the recessed front portion and substantially wholly within the cavity, and configured to enable the transparent visor to be pivoted from a first position substantially within the cavity to a second, operable position generally perpendicular to a user's eyeline.

A protective helmet comprising a head mountable shell (10) and a transparent visor (24), the head mountable shell defining a rear portion and an opposing front portion (12) when oriented for use, the front portion being recessed, the helmet further comprising a cover portion (16) mountable over the recessed front portion so as to define a cavity, the transparent visor being pivotally mounted across the recessed front portion by means of a pair of pivot mechanisms (28), the pivot mechanisms being located at opposing sides of the recessed front portion and substantially wholly within the cavity, and configured to enable the transparent visor to be pivoted from a first position substantially within the cavity to a second, operable position generally perpendicular to a user's eyeline.

There is provided a visor assembly, preferably for the motorcycle helmet, comprising a shield-visor having a surface, an overlay-visor adapted to be releasably attached to the shield-visor, the overlay-visor comprising a viewing area, a spacer with a tackified distal surface gasket, releasably adhering the overlay-visor to the surface of the shield-visor.