Anti-entrapment Device for Scissor Lifts

Abstract

The present invention provides an anti-entrapment device for an aerial lift having a basket or cage. The anti-entrapment device comprises an elongate housing; two or more sensors housed within said elongate housing and a switch activation device coupled to the elongate housing. At least one of said two or more sensors is positioned proximate an end of said elongate housing. Said switch activation device is arranged at an angle to the orientation of said sensor(s) positioned proximate the end of said elongate housing. The sensors are arranged to provide a detection zone and to detect obstacles within the detection zone. The sensors are configured to facilitate the alerting of an operator standing in a basket or cage to the presence of an obstacle that may potentially strike the operator before the strike occurs, and the switch activation device is configured to prevent further movement of the basket or cage once the switch activation device is activated.

1 . An anti-entrapment device for an aerial lift having a basket or cage, the anti-entrapment device comprising:
 an elongate housing;   two or more sensors housed within said elongate housing, at least one of said two or more sensors positioned proximate an end of said elongate housing;   a switch activation device coupled to the elongate housing, said switch activation device arranged at an angle to the orientation of said sensor(s) positioned proximate the end of said elongate housing;   wherein the sensors are arranged to provide a detection zone and to detect obstacles within the detection zone;   the sensors configured to facilitate the alerting of an operator standing in a basket or cage to the presence of an obstacle that may potentially strike the operator before the strike occurs, and   the switch activation device configured to prevent further movement of the basket or cage once the switch activation device is activated.   
     
     
         2 . The anti-entrapment device of  claim 1 , wherein the anti-entrapment device includes two sensors, each sensor located proximate an end of the elongate housing. 
     
     
         3 . The anti-entrapment device of  claim 2 , wherein the elongate housing is between 50 cm and 100 cm in length. 
     
     
         4 . The anti-entrapment device of  claim 2 , further comprising a plurality of braces configured to support the elongate housing in a position above and parallel to a top rail of a basket or cage. 
     
     
         5 . The anti-entrapment device of  claim 2  wherein the switch activation device comprises a pressure sensitive safety edge. 
     
     
         6 . The anti-entrapment device of  claim 2  further comprising an operator warning system. 
     
     
         7 . The anti-entrapment device of  claim 6  wherein the operator warning system comprises one or more warning lights mounted on the elongate housing. 
     
     
         8 . The anti-entrapment device according to  claim 2  wherein the sensors are ultrasonic sensors. 
     
     
         9 . A basket or cage for a scissor lift, said basket or cage comprising:
 an anti-entrapment device according to  claim 2 ;   controls which permit an operator standing in the basket or cage to manoeuvre it, the controls comprising:
 an emergency switch which normally allows the flow of electricity and is operable to stop electrical supply and prevent movement of the basket or cage, and 
 a function enable switch which is normally open to cut electrical supply and prevent movement of the basket or cage and which must be held closed by the operator to allow the flow of electricity and enable the operator to operate the controls; 
   an alarm which is either audible, visual or audible and visual;   a primary relay connected to the function enable switch;   a secondary relay connected to the emergency switch;   the primary and secondary relays being controlled by a programmable control module connected to the switch activation device, function enable switch and alarm;   wherein the control module is programmed to prevent movement of the basket or cage by cutting electrical supply to the function enable switch when the function enable switch is closed and the switch activation device is activated, and to activate the alarm.   
     
     
         10 . The basket or cage of  claim 9 , wherein if the electrical supply to the function enable switch cannot be cut, the control module is further programmed to prevent movement of the basket or cage and activate the alarm by operating the emergency switch to cut the electrical supply. 
     
     
         11 . The basket or cage according to  claim 10  wherein the function enable switch is a dead man's handle. 
     
     
         12 . The basket or cage according to  claim 9  wherein the alarm is located on an underside of the elongate housing of the anti-entrapment device. 
     
     
         13 . The basket or cage according to  claim 9  wherein the scissor lift has a horn and the alarm is an audible alarm which utilises the horn. 
     
     
         14 . The basket or cage according to  claim 13  wherein the horn sounds a unique sounding pattern. 
     
     
         15 . The basket or cage according to  claim 13  wherein the alarm is linked to the horn via a communications link such as an RS232 interface. 
     
     
         16 . The basket or cage according to  claim 9  wherein the alarm is visual and flashes for a period of time when the switch activation device is activated. 
     
     
         17 . The basket or cage according to  claim 9  wherein the control module is further programmed to perform a self-diagnostic test when the anti-entrapment device is first turned on, and if the anti-entrapment device fails the diagnostic test the control module is programmed to activate a fault warning system. 
     
     
         18 . The basket or cage according to  claim 9  further comprising a switch activation device reset switch connected to the control module. 
     
     
         19 . The basket or cage according to  claim 18  wherein the reset switch is located on said controls. 
     
     
         20 . The basket or cage according to  claim 9  wherein the control module is further programmed to delay activation of the cutting electrical supply to the function enable switch upon activation of the switch activation device. 
     
     
         21 . The basket or cage according to  claim 20  wherein the delay is approximately 0.4 seconds. 
     
     
         22 . The basket or cage according to  claim 9  further comprising an information link to a data collection device. 
     
     
         23 . The basket or cage according to  claim 9  wherein additional modules can be plugged into the control module. 
     
     
         24 . The basket or cage according to  claim 9  wherein the basket or cage has a scissor lift control box and the control module is housed within the scissor lift control box. 
     
     
         25 . The basket or cage according to  claim 9  comprising two or more anti-entrapments devices;
 said two or more anti-entrapment devices each comprising:
 an elongate housing;
 two or more sensors housed within said elongate housing, at least one of said two or more sensors positioned proximate an end of said elongate housing; 
 a switch activation device coupled to the elongate housing, said switch activation device arranged at an angle to the orientation of said sensor(s) positioned proximate the end of said elongate housing; 
 wherein the sensors are arranged to provide a detection zone and to detect obstacles within the detection zone; 
 the sensors configured to facilitate the alerting of an operator standing in a basket or cage to the presence of an obstacle that may potentially strike the operator before the strike occurs, and 
 the switch activation device configured to prevent further movement of the basket or cage once the switch activation device is activated; 
 wherein said anti-entrapment devices are positioned and connected in series with one another. 
 
 
 
     
     
         26 . The basket or cage according to  claim 9  wherein the or each anti-entrapment device is removably attached to the basket or cage. 
     
     
         27 . The basket or cage according to  claim 9  wherein the or each anti-entrapment device is permanently attached to the basket or cage. 
     
     
         28 . The basket or cage according to  claim 25  wherein each anti-entrapment device is located such that said elongate housing does not protrude either into or out of the basket or cage. 
     
     
         29 . The basket or cage according to  claim 9  wherein the detection zone extends approximately 210 cm above the floor of the basket or cage. 
     
     
         30 . The basket or cage according to  claim 9  wherein the sensors do not detect the position of the operator inside the basket or cage. 
     
     
         31 . The basket or cage according to  claim 24 , wherein the control box comprise a control panel having one or more warning lights mounted on the control panel. 
     
     
         32 . The basket or cage according to  claim 9 , wherein the basket or cage is a scissor lift basket or cage. 
     
     
         33 . A scissor lift comprising a basket or cage according to  claim 9 . 
     
     
         34 . A method of preventing the crushing of an operator standing in a basket or cage of an aerial lift by an obstacle striking said operator, said method comprising the steps:
 a. installing a plurality of sensors to the basket or cage to establish a detection zone,   b. installing a switch activation device proximate a control box of said aerial lift,   c. connecting the sensors and the switch activation device to a control module capable of preventing movement of the basket or cage and/or alerting the operator to the presence of an obstacle,   d. monitoring the detection zone for an obstacle entering the detection zone,   e. sending a signal from the sensors to the control module to instruct the control module to alert the operator and/or to prevent movement of the basket or cage when an obstacle is detected within the detection zone,   f. preventing movement of the basket or cage on activation of the switch activation device.   
     
     
         35 . The method of  claim 34 , wherein when the sensors detect an obstacle and activate an alarm and/or warning system, the operator can override the alarm and/or warning system by activating an override procedure. 
     
     
         36 . An anti-entrapment device for an aerial lift having a basket or cage, the anti-entrapment device comprising:
 an elongate housing, said elongate housing being between 50 cm and 100 cm in length;   two or more sensors housed within said elongate housing, at least one of said two or more sensors positioned proximate an end of said elongate housing;   a switch activation device coupled to the elongate housing, said switch activation device arranged at an angle to the orientation of said sensor(s) positioned proximate the end of said elongate housing, said switch activation device comprising a pressure sensitive safety edge; and   a plurality of braces configured to support the elongate housing in a position above and parallel to a top rail of a basket or cage.