Abstract: A coupler for interconnecting a damper blade shaft having a keyed end with an actuator is provided whereby movement of the actuator is imparted to the damper blade shaft via the coupler. The coupler comprises a socket adapted to receive the keyed end of the damper blade shaft in at least two angular positions and a connector adapted to receive a portion of the actuator. The damper blade shaft can thereby be indexed to any one of the at least two positions relative to the actuator without additional fasteners when the keyed end of the damper blade shaft is received in the socket.

Abstract: A retainer bracket for an electric heating assembly is provided with a pair of parallel and opposing side beams having longitudinal axes and at least one planar transverse support formed integral with the pair of side beams and extending between the pair of side beams. The transverse support preferably has a plurality of openings with longitudinal axes and the transverse support is disposed so that the axes of the openings are parallel to the longitudinal axes of the side beams. The plurality of openings are thereby each adapted to receive and retain an insulator without a separate fastener. A method of making the heating coil retainer bracket from a single web of material is also contemplated.

Abstract: An open coil electric heater comprising a rigid support frame composed of a pair of longitudinally extending, laterally spaced members, with cross members between and secured to the longitudinal members. The cross members carry ceramic insulator members which are detachably connected to the cross members. Each insulator member has an end formed with a slot at an acute angle to the side walls of the insulator member to pass a portion of a convolution of an electrical wire coil. Hook-like projections form a transverse indentation at the base of the slot to detachably hold the portion of the wire om the insulator member. The portion of the wire is secured to the insulator members in an expeditious manner and without the use of tools by twisting the wire portion so that the wire portion is aligned sufficiently with the slot to enable the coil to freely pass into said slot.

Abstract: A sensor in an air conditioning duct produces a differential pressure signal which varies as a function of the volumetric flow rate of air through the duct. The sensor includes an array of angularly spaced and radially extending arms disposed around and across the duct and each having upstream and downstream sensing tubes formed with ports spaced along their upstream and downstream sides, respectively. Pressure signals are transmitted to the tubes by way of the ports and are averaged by high and low pressure averaging chambers located at the center of the sensor and communicating with the upstream and downstream sensing tubes, respectively. The output signals from the averaging chambers constitute a differential pressure signal which is highly representative of the volumetric flow rate of the air even though the air flows through the duct in an asymmetrical pattern.

Abstract: A volume air flow controller having a butterfly damper mounted within an air duct and movable between open and closed positions employs a baffle, located upstream from the damper, as an air flow impedance to change the flow conditions upstream from the damper so as to reduce the normal damper closing torque resulting from aerodynamic forces produced by air flow past the damper.