A device. The device includes a shaft having a longitudinal axis, a first end, and a second end. The device also includes a connector attached to the first end of the shaft. The device also includes a rod connected to the shaft. The rod comprises a third end and a fourth end. The third end is connected to the second end of the shaft. The rod is about parallel to the longitudinal axis. The device also includes a spring surrounding the rod. The spring is compressible or extendable along the longitudinal axis. The device also includes a stop connected to the rod at a position distal to the spring. The stop resists longitudinal compression or extension of the spring.

Methods and apparatus to wirelessly interlock doors are disclosed. A door system includes a user interface to receive interlock configuration data input from a user, the interlock configuration data to define an interlock condition to be satisfied before a first door is to undergo an operation, the interlock condition associated with a current state of a second door. The door system includes a first wireless transceiver to receive a signal from a second wireless transceiver associated with a second door. The method includes a door operation controller to at least one of (1) implement the operation of the first door in response to a request when the current state of the second door satisfies the interlock condition, (2) ignore the request, or (3) not execute the operation of the first door in response to the request when the current state of the second door does not satisfy the interlock condition.

A door braking system includes: a shaft; a brake pad configured to be mounted to the shaft; a plate for mounting on the shaft adjacent to the brake pad; a spring for urging the plate to the brake pad, the spring configured to be mounted on the shaft; a nut dimensioned and sized to be mounted on the shaft for adjusting an amount of force the spring urges the plate against the brake pad. A method of applying variable amount of braking force to a door includes: attaching a brake pad and brake plate to a shaft; configuring a spring to urge the brake plate against the brake pad; mounting an adjustment piece to the shaft; and configuring the adjustment piece to move axially on the shaft as the shaft rotates to thereby vary a force the spring urges against the brake plate.

In one aspect of the present disclosure, a movable barrier operator system is provided that includes a motor configured to turn a drum to pay out a cable from the drum and permit a door connected to the cable to move from an open position toward a closed position. The system includes a memory configured to store an expected variable of the door, and a sensor configured to detect movement of the door. The system further includes a processor circuit operatively coupled to the motor, the memory, and the sensor. The processor circuit is configured to: use the sensor to estimate an actual variable of the door; determine whether the actual variable is acceptable based at least in part on the expected variable and the processor circuit causing the motor to turn the drum; and change operation of the movable barrier upon the actual variable of the movable barrier being unacceptable.

In one aspect, a method is provided for controlling access to a facility including a movable barrier and a plurality of loading docks. The method includes receiving, from a user device associated with a vehicle, a check-in communication that includes a check-in identifier. The method includes receiving a verification communication that verifies a presence of the vehicle relative to a sensor associated with the movable barrier. The method further includes causing a movable barrier operator associated with the movable barrier to move the movable barrier between closed and open positions in response to the check-in identifier indicating authorization to access the facility and in response to receiving the verification communication. Further, the method includes selecting a particular loading dock from the plurality of loading docks and communicating a loading dock identification representative of the particular loading dock to the user device to direct the vehicle to the particular loading dock.

In one aspect of the present disclosure, a movable barrier operator system is provided that includes a motor configured to turn a drum to pay out a cable from the drum and permit a door connected to the cable to move from an open position toward a closed position. The system includes a memory configured to store an expected variable of the door, and a sensor configured to detect movement of the door. The system further includes a processor circuit operatively coupled to the motor, the memory, and the sensor. The processor circuit is configured to: use the sensor to estimate an actual variable of the door; determine whether the actual variable is acceptable based at least in part on the expected variable and the processor circuit causing the motor to turn the drum; and change operation of the movable barrier upon the actual variable of the movable barrier being unacceptable.

In example implementations, a method is provided. The method includes determining, by a processor, that a vehicle is approaching a door of a building based on a velocity vector of the vehicle, calculating, by the processor, a time of arrival of the vehicle at the door based on the velocity vector of the vehicle and a distance of the vehicle from the door, and controlling, by the processor, the door to begin opening at a time based on the time of arrival and an amount of time for the door to open such that the door is opened when the vehicle arrives at the door.

A cap for mounting on a hinge is described. The cap includes: a body defining a first attaching portion for attaching the body to a hinge at a first location; a second attaching portion defined by the body for attaching the body to the hinge at a second location; and a channel defined by the body wherein the body is configured to secure a rod to the hinge by trapping the rod in the channel between the body and the hinge and the channel is located between the first and second attaching portions.

A ratcheted Pipe and Strap Operating Drive System (PSODS) is disclosed which efficiently and accurately positions a blocker, or door mechanism, over an opening which is of similar profile and dimensions as the door mechanism. In the preferred embodiment, PSODS is used to vary the position of a poultry house ventilation blocker or door mechanism from a tightly-closed position against the opening, or when required, within a certain range of door mechanism open positions, as dictated by weather conditions or internal air quality. At least two ratcheted reels are co-axially connected to the exterior of a tubular pipe drive. Each reel is connected, at its core, to the first end of a strap, with the second end of the strap being connected to the door mechanism. Upon axial rotation of the pipe drive in either direction, the reels simultaneously rotate, straps move correspondingly so as to position the entire door mechanism within a desired range relative to the opening.

Light grid for protecting the door edge of a motor-driven door against collision with an object, having a transmitter strip and a receiver strip with transmitter elements and receiver elements, for detecting an object in the plane of the door panels by interruption of the reception of individual receiver elements. An evaluation device distinguishes between normal and safety cases based on the detection of a status for the door, identifies the safety case if the number of uninterrupted receiving elements between door edge and object falls below a critical number, and identifies the normal case if the safety case is not identified. A communication device outputs a signal for the status. The evaluation device determines a distance value corresponding to the number of uninterrupted receiver elements below the door edge up to the first interrupted element, and the communication device varies the frequency as a function of the distance value.