Method And Apparatus For Feeding Fasteners To A Processing Device

Abstract

A method and apparatus for feeding fasteners with at least two parallel boundary surfaces to a processing device includes lining up the fasteners in the same orientation by a feeder. The fasteners move through a conveying duct to a loading device arranged on a processing device. Individual conveying steps are separated from one another in time. At each conveying step a column of multiple fasteners in the same orientation, with their parallel boundary surfaces resting on one another, is conveyed by the feeder to the loading device by introducing air into the conveying duct. The loading device has, adjoining a magazine output end, a loading duct extending perpendicular to a magazine longitudinal axis, terminating in a processing device working duct. The loading duct has a conveying mechanism which conveys individual fasteners emerging from the magazine into the working duct one at a time.

1 . An apparatus for feeding fasteners having at least two parallel boundary surfaces to a processing device, comprising: 
 a feeder operable to place a plurality of fasteners in a consistent orientation;    a conveying duct connected to the feeder;    a magazine connected to the conveying duct operable to receive the fasteners from the conveying duct;    a throttling port located at a magazine end of the conveying duct; and    a column defining a portion of the fasteners formed for transport through the conveying duct, with proximate ones of the boundary surfaces of the individual fasteners resting one against the other, a back end of the column being subjected to compressed fluid introduced into the conveying duct defining a propulsive force operable to drive the column through the conveying duct to the magazine, and a compressive force acting on a front end of the column generated by resistance from a volume of fluid in front of the column in the conveying duct being forced through the throttling port, a combination of the propulsive force and the compressive force acting to press the fasteners in the column against one another to prevent the fasteners from assuming an orientation that would impede their sliding through the conveying duct.    
   
   
       2 . The apparatus of  claim 1 , further comprising a loading device operable to receive the fasteners and position the fasteners for installation.  
   
   
       3 . The apparatus of  claim 2 , further comprising a loading duct of the loading device adjoining an output end of the magazine, the loading duct extending perpendicular to a longitudinal axis of the magazine and terminating in a working duct of the processing device.  
   
   
       4 . The apparatus of  claim 3 , further comprising a conveying mechanism of the loading duct operable to convey individual ones of the fasteners emerging from the magazine into the working duct of the processing device one at a time.  
   
   
       5 . The apparatus of  claim 4 , further comprising a piston operable to drive the conveying mechanism.  
   
   
       6 . The apparatus of  claim 4 , further comprising: 
 a working duct elastically expadable to receive individual ones of the fasteners from the conveying mechanism; and    a die oriented perpendicular to the loading duct and adapted to force the individual ones of the fasteners through the working duct into a workpiece.    
   
   
       7 . The apparatus of  claim 6 , further comprising a detent pawl operably biased by a biasing member to contact and temporarily hold individual ones of the fasteners for contact by the die.  
   
   
       8 . The apparatus of  claim 1 , wherein individual ones of the plurality of fasteners each have an unfavorable aspect ratio defining a diameter greater than an axial thickness.  
   
   
       9 . An apparatus for feeding fasteners having at least two parallel boundary surfaces to a processing device, comprising: 
 a feeder operable to place the fasteners in a consistent orientation;    a conveying duct connecting the feeder to a loading device arranged on a processing device;    a magazine associated with the loading device accommodating a column of multiple fasteners delivered through the conveying duct in the same orientation, the fasteners having parallel boundary surfaces abutting one another;    a loading duct of the loading device adjoining an output end of the magazine, the loading duct extending perpendicular to a longitudinal axis of the magazine and terminating in a working duct of the processing device; and    a conveying mechanism of the loading duct operable to convey individual ones of the fasteners emerging from the magazine into the working duct of the processing device one at a time.    
   
   
       10 . The apparatus of  claim 9 , wherein the loading device includes a loading slide movable back and forth in the loading duct with the aid of a pneumatically driven piston.  
   
   
       11 . The apparatus of  claim 10 , comprising: 
 a loading slide path of motion extending over only a portion of a length of the loading duct; and    a pneumatic conveying mechanism activated by movement of the loading slide operable to convey the fasteners on a section of the loading duct not traversed by the loading slide.    
   
   
       12 . The apparatus of  claim 10 , comprising: 
 a pneumatic working cylinder having a double-acting piston and a piston rod connected to the loading slide; and    a passage in communication with a working chamber of the pneumatic working cylinder, the piston rod and the loading slide traversed lengthwise by the passage when the loading slide is in a position advanced toward the working duct.    
   
   
       13 . The apparatus of  claim 12 , further comprising a valve needle arranged in the working cylinder operable to control the pneumatic conveying mechanism, wherein in a first position of the piston, the valve needle is projected into the piston end of the passage, thus closing it, and wherein in a second position of the piston, the valve needle is withdrawn from the passage, causing the passage to be connected to the working chamber.  
   
   
       14 . The apparatus of  claim 13 , further comprising a sensor operable to detect when the quantity of fasteners in the magazine falls below a minimum level, the sensor further operable to trigger a control process operable to convey a next column of fasteners to the magazine.  
   
   
       15 . The apparatus of  claim 13 , further comprising a counter operable to detect when the quantity of fasteners in the magazine falls below a minimum level, the sensor further operable to trigger a control process operable to convey a next column of fasteners to the magazine.  
   
   
       16 . The apparatus of  claim 13 , further comprising: 
 each of the fasteners having a head section including a truncated cone shape; and    a top edge of the loading duct extending outward at an angle on opposite sides of the loading duct operable to match the truncated cone shape of the head section of the fasteners.    
   
   
       17 . A method for feeding fasteners with at least two parallel boundary surfaces to a processing device, the method comprising: 
 placing the fasteners in readiness, lined up in a same orientation by a feeder;    connecting a conveying duct between the feeder to a loading device arranged on the processing device;    moving the fasteners in individual conveying steps which are separated from one another in time through the conveying duct;    grouping the fasteners during individual ones of the individual conveying steps as a column of multiple fasteners in the same orientation with the parallel boundary surfaces resting on one another using pressurized air introduced behind the column in the conveying duct; and    maintaining the individual fasteners of the column in contact with each other by introducing a fluid backpressure at a forward end of the column.    
   
   
       18 . The method according to  claim 17 , comprising feeding the column of fasteners to the loading device into a magazine of the loading device.  
   
   
       19 . The method according to  claim 18 , comprising: 
 individually removing the fasteners from the magazine by the loading device; and    feeding the fasteners to the processing device as a function of a processing cycle.    
   
   
       20 . The method according to  claim 19 , comprising conveying the fasteners through the conveying duct to the magazine of the loading device as a function of one of the processing cycle and a fill level in the magazine.  
   
   
       21 . The method according to  claim 18 , comprising accomplishing the conveyance of the individual fasteners from the magazine to the processing device partially mechanically and partially pneumatically.  
   
   
       22 . The method according to  claim 17 , comprising adjusting a quantity of fasteners per column to adapt to an operating speed of the processing device.  
   
   
       23 . The method according to  claim 17 , comprising adjusting a quantity of fasteners per a time interval between individual column conveying cycles to adapt to an operating speed of the processing device.