Abstract: An electrified fire fighting vehicle includes a battery pack, an electromagnetic device, an engine, and a controller. The controller is configured to monitor a state-of-charge of the battery pack, operate the electromagnetic device using stored energy in the battery pack to provide a performance condition including (i) accelerating the electrified fire fighting vehicle to a driving speed of at least 50 miles-per-hour in an acceleration time and (ii) maintaining or exceeding the driving speed for a period of time, and start and operate the engine in response to a start condition to facilitate reserving sufficient stored energy in the battery pack such that the state-of-charge is maintained above a minimum state-of-charge threshold that is sufficient to facilitate the performance condition. The acceleration time is 30 second or less. An aggregate of the acceleration time and the period of time is at least 3 minutes.

Abstract: A quick disconnect mechanism for a detachable stair system for vehicles. The apparatus includes mounting brackets for installation at either side of a doorway in a recreational vehicle such as motorhome, camping trailer, or camper on a pickup truck. Fixed plates in the form of open jaw brackets are provided at each side of a sill cover plate, to enable operation of a pivotable detachable stair portion. The open jaw of the fixed plates are pivotable about pivot studs located in the mounting brackets. The fixed plates further include an arcuate channel defined radially outward from the pivots studs. The arcuate slot is sized and shaped for engagement with a pivot lock also located on the mounting brackets. The pivot locks extend inward for sliding operation with the arcuate slot, but not so far inward as to interfere with the pivoting motion of the sill cover plate.

Abstract: A quick disconnect mechanism for a detachable stair system for vehicles. The apparatus includes mounting brackets for installation at either side of a doorway in a recreational vehicle such as motorhome, camping trailer, or camper on a pickup truck. Fixed plates in the form of open jaw brackets are provided at each side of a sill cover plate, to enable operation of a pivotable detachable stair portion. The open jaw of the fixed plates are pivotable about pivot studs located in the mounting brackets. The fixed plates further include an arcuate channel defined radially outward from the pivots studs. The arcuate slot is sized and shaped for engagement with a pivot lock also located on the mounting brackets. The pivot locks extend inward for sliding operation with the arcuate slot, but not so far inward as to interfere with the pivoting motion of the sill cover plate.

Abstract: A retractable stair assembly for vehicles. In an embodiment, the retractable stair assembly may be detachable. Mounting brackets may be provided at opposing sides of a floor plate, and a one-piece mounting bracket assembly provided for installation at the threshold of a door in a recreational vehicle. Pivot plates are provided for pivotal movement of a retractable stair assembly about pivot studs provided on the mounting brackets. Pivot plates may be in the form of open jaw brackets provided at each side of a sill cover plate, to enable removal of the retractable stair assembly. A sill cover plate is provided that is shaped and sized to fit over the threshold and sill in a recreational vehicle doorway, yet allow closure of the door. In an embodiment a bottom stair is independently deployable, so the stair may be used, or not used, as may be appropriate at a given location.

Abstract: A quick disconnect mechanism for a detachable stair system for vehicles. The apparatus includes mounting brackets for installation at either side of a doorway in a recreational vehicle such as motorhome, camping trailer, or camper on a pickup truck. Fixed plates in the form of open jaw brackets are provided at each side of a sill cover plate, to enable operation of a pivotable detachable stair portion. The open jaw of the fixed plates are pivotable about pivot studs located in the mounting brackets. The fixed plates further include an arcuate channel defined radially outward from the pivots studs. The arcuate slot is sized and shaped for engagement with a pivot lock also located on the mounting brackets. The pivot locks extend inward for sliding operation with the arcuate slot, but not so far inward as to interfere with the pivoting motion of the sill cover plate.

Abstract: An audio preamplifier includes a first stage including a first triode of a first vacuum tube in a common cathode configuration configured to perform a first gain function favoring one of low frequencies and mid-range frequencies in response to user input; a second stage including a second triode of the first vacuum tube in a common cathode configuration configured to perform a second gain function favoring one of low frequencies and mid-range frequencies in response to user input; a third stage including a first triode of a second vacuum tube in a common cathode configuration configured to perform a tone-shaping function favoring one of low frequencies and mid-range frequencies in response to user input; and a fourth stage including a second triode of the second vacuum tube in a follower configuration configured to perform a tone stack function in response to user input.

Abstract: A retractable stair assembly for vehicles. In an embodiment, the retractable stair assembly may be detachable. Mounting brackets may be provided at opposing sides of a floor plate, and a one-piece mounting bracket assembly provided for installation at the threshold of a door in a recreational vehicle. Pivot plates are provided for pivotal movement of a retractable stair assembly about pivot studs provided on the mounting brackets. Pivot plates may be in the form of open jaw brackets provided at each side of a sill cover plate, to enable removal of the retractable stair assembly. A sill cover plate is provided that is shaped and sized to fit over the threshold and sill in a recreational vehicle doorway, yet allow closure of the door. In an embodiment a bottom stair is independently deployable, so the stair may be used, or not used, as may be appropriate at a given location.

Abstract: A quick disconnect mechanism for a detachable stair system for vehicles. The apparatus includes mounting brackets for installation at either side of a doorway in a recreational vehicle such as motorhome, camping trailer, or camper on a pickup truck. Fixed plates in the form of open jaw brackets are provided at each side of a sill cover plate, to enable operation of a pivotable detachable stair portion. The open jaw of the fixed plates are pivotable about pivot studs located in the mounting brackets. The fixed plates further include an arcuate channel defined radially outward from the pivots studs. The arcuate slot is sized and shaped for engagement with a pivot lock also located on the mounting brackets. The pivot locks extend inward for sliding operation with the arcuate slot, but not so far inward as to interfere with the pivoting motion of the sill cover plate.

Abstract: An audio preamplifier includes a first stage including a first triode of a first vacuum tube in a common cathode configuration configured to perform a first gain function favoring one of low frequencies and mid-range frequencies in response to user input; a second stage including a second triode of the first vacuum tube in a common cathode configuration configured to perform a second gain function favoring one of low frequencies and mid-range frequencies in response to user input; a third stage including a first triode of a second vacuum tube in a common cathode configuration configured to perform a tone-shaping function favoring one of low frequencies and mid-range frequencies in response to user input; and a fourth stage including a second triode of the second vacuum tube in a follower configuration configured to perform a tone stack function in response to user input.

Abstract: A retractable stair system for vehicles. The apparatus includes stairs which are retractable into a frame, or extendable to provide a set of stairs with relatively uniform height therebetween. Indexing plates with locking notches and companion latches with latch tongues to fit in the notches enable adjustment of the height of a top step S1 in a set of steps in an extensible-retractable stairs assembly. Extensible legs are provided which are individually vertically adjustable to provide secure engagement with an uneven substrate such as rocky ground or a sloping surface. Foot pads are pivotally attached to the extensible legs. The combination of vertical adjustability, the selection of a desired number of stairs, and individual top stair height adjustability, make the unit adaptable for use in a variety of vehicles.

Abstract: Load stabilizing inserts for a motor vehicle. The inserts include a base plate, a top plate spaced apart from and angularly pivotable with respect to the base plate, and one or more contact plates. The insert is sized and shaped for insertion between an overload spring and a spring pack in a motor vehicle such as a pickup truck. Four load stabilizing inserts may be installed to provide stable operation of the pickup truck when loaded at or near the maximum design gross operating weight of the vehicle. During those periods when the truck is not loaded, such as when a truck camper is not installed, the load stabilizing inserts may be angularly adjusted and secured in an open, non-working position, to provide a relatively soft ride during such position.

Abstract: Load stabilizing inserts for a motor vehicle. The inserts include a base plate, a top plate spaced apart from and angularly pivotable with respect to the base plate, and one or more contact plates. The insert is sized and shaped for insertion between an overload spring and a spring pack in a motor vehicle such as a pickup truck. Four load stabilizing inserts may be installed to provide stable operation of the pickup truck when loaded at or near the maximum design gross operating weight of the vehicle. During those periods when the truck is not loaded, such as when a truck camper is not installed, the load stabilizing inserts may be angularly adjusted and secured in an open, non-working position, to provide a relatively soft ride during such position.

Abstract: A camper tie-down. The tie down is provided for mounting a load such as a camper to pre-existing mounting structure on a motor vehicle frame, such as a hitch or frame portion. The tie-down includes a retractable base portion, an adjustable tension member, and a shock absorbing cushioning member. The tie-down minimizes or eliminates drilling, cutting, welding or other custom mounting structure for installation on most vehicles. One embodiment includes bullet shaped extension plates for extending the attachment point of arms forward or rearward, as appropriate depending on whether the attachment is to be made at the front or at the rear of the vehicle.

Abstract: A camper tie-down. The tie down is provided for mounting a load such as a camper to pre-existing mounting structure on a motor vehicle frame, such as a hitch or frame portion. The tie-down includes a retractable base portion, an adjustable tension member, and a shock absorbing cushioning member. The tie-down minimizes or eliminates drilling, cutting, welding or other custom mounting structure for installation on most vehicles. One embodiment includes bullet shaped extension plates for extending the attachment point of arms forward or rearward, as appropriate depending on whether the attachment is to be made at the front or at the rear of the vehicle.

Abstract: A retractable camper tie-down. The tie down is provided for mounting a load such as a camper to pre-existing mounting structure on a motor vehicle frame. The tie-down includes a retractable base portion, an adjustable tension member, and a shock absorbing cushioning member. The tie-down requires no drilling, cutting, welding or other custom mounting structure for installation on most vehicles.