Electronic bulk feeder for small assembly components

In a feeder supplying assembly components to another machine, an electronic control device monitors a horizontal buffer zone. Pulses of compressed gas are intermittently employed to lift components upon detecting the absence of a component in a portion of such buffer zone. The grooved chute member has a shape resembling the symbol for a square root after replacing the angles with curves. The stream of flowing components can be quite fast because components are directed to fall into the downsloping gathering portion of the grooved chute at an upper, middle, and lower portions. More rapid multi-stage alignment of components is expedited by a zone underneath a deflector and a transition zone, with an alignment passageway between such zones.

BACKGROUND OF THE INVENTION
 This invention relates to improvements in the apparatus for feeding
 assembly components from a bulk supply zone into a pick-up zone in which
 component can be picked up for transfer to another machine, such as a
 robotic assembly machine. The feeder of the present invention is useful
 for many varieties of machines. Conventional feeders usually are a part of
 the assembly machine for which they are designed, and cannot ordinarily be
 used in another environment. Conventional feeders usually have been
 activated by some operation of the robotic assembly machine. Convention
 feeders have generally advanced a component from the bulk to the pick-up
 position by gravity or gravity assisted by a belt, or vibration or a
 compressed gas.
 In convention feeders, the component at the pick-up position has oftentimes
 been subjected to the pressure of a gravitationally flowing stream of
 components, thus making it more difficult for the robotic assembly machine
 to pick up the component by vacuum. Hence some feeder have included
 additional mechanisms for adequately individualizing a component for
 transfer to a pickup zone, thereby increasing the propensities for jamming
 and other malfunctions. Most feeders have been purely mechanical feeders
 lacking adequate communication systems for alerting the operator and/or
 the robotic assembly machine concerning the status of the feeding
 mechanism. Heretofore the stream of flowing components from the bottom of
 a hopper has been unsatisfactorily slow, thus limiting the practical speed
 at which the robotic assembly machine could function.
 BRIEF SUMMARY OF INVENTION
 The present invention features a horizontal buffer zone so that a plurality
 of components are normally maintained in a tubular buffer zone and
 disentangled from the pressure of the flow of the stream of components to
 such horizontal buffer zone. Compressed gas is employed in advancing a
 stream of components toward the buffer zone, but gas dissipation means are
 provided at and/or near the end of the buffer zone so that a leading
 component is merely nudged into the pickup station. In order to slow down
 the speed of a component while flowing through the buffer zone,
 appropriate venting means, such as a plurality of holes, permits more and
 more dissipation of some of the compressed gas as the component advances
 through the buffer zone toward such pickup station. The open-topped pick
 up station at the exit of the buffer zone receives a component which has
 been merely nudged out of the buffer zone. A hard stop prevents a
 component from being nudged beyond such hard stop. At least one, and
 usually a plurality of detection means, such as an optical switch,
 identify the moments when components are absent from various portions of
 the buffer zone. Signals from such detection means influence an electronic
 control means so that a pulse of compressed gas is released for advancing
 at least one component toward said buffer zone. Thus, the feeder
 consistently provides a component at the pickup station, ready for
 transfer to another machine such as a robotic assembly machine. The
 components flow from a bulk supply in a hopper to the buffer zone at a
 speed which is faster than for convention feeders.
 Certain preferred embodiments of the invention include supplemental
 improvements. The components flow gravitationally from the bulk supply in
 a hopper through a gathering zone toward a curved portion of a grooved
 chute. Said gathering zone features a downsloping portion of said grooved
 chute. Particular attention is directed to an upsloping lift portion of
 such grooved chute and to the use of compressed gas for lifting one or
 more components for flow through an upper curved portion of such grooved
 chute into the horizontal buffer zone.
 Thus the shape of the groove desirably has some resemblance to the symbol
 for a square root in which the angles are replaced by appropriate curves.
 Certain embodiments schedule components to fall into such groove at a
 plurality of zones, thereby permitting a flowing stream of components
 which is significantly faster than would be attainable if there were only
 a single zone in which, following the laws of probability, a component
 might fall gravitationally into such groove.
 In some embodiments of the invention in which a groove has a shape
 resembling a curved square root symbol, and in which the downsloping
 portion of the path of the groove is at the downwardly sloping bottom of
 hopper, a flexible deflector is positioned near about half way down the
 sloping bottom of the hopper. Such flexible deflector can be yieldingly
 deflected to permit components to flow gravitationally into a zone
 underneath such deflector. Some of the components under such deflector can
 fall into the groove at one or more of the supplemental zones. Some
 embodiments of the invention include a jet permitting the deflector to be
 vibrated by a pulse of compressed gas when the control means stimulates
 and intermittent pulse of compressed gas. The vibration of the deflector
 also tumbles the bulk components in that portion of the hopper adjacent to
 such deflector. Some embodiments of the invention provide for a transition
 zone in which the walls direct partially aligned components to fall
 gravitationally into the groove, there being a passageway between the zone
 under the deflector and the transition zone for such partial alignment of
 components. Some embodiments of the invention include one of more
 dislodging jets positioned to direct the intermittent pulses of compressed
 gas to zones in which components might bridge in such a manner as to delay
 the flow of components toward the buffer zone. Some embodiments of the
 invention provide visual or other communication to another device and/or
 the operator.

DETAILED DESCRIPTION OF THE INVENTION
 One merely illustrative example of the invention is shown in FIGS. 1-10. A
 feeder includes a horizontal buffer zone from which a component 2 can be
 nudged onto a pickup station 3. A hard stop 4 halts a component 2 from
 going beyond such pickup station 3, which is open-topped. Hence the
 robotic assembly machine has access to a component at the pickup station
 3. Because the pickup station 3 is open-topped, any residual gas pressure
 near the exit of the buffer zone is readily dissipated. The buffer one
 comprises a transparent cover 5 over a groove 6, thereby providing a
 tubular passageway for the flowing stream of components 2. Particular
 attention is directed to holes 7 permitting the dissipation of compressed
 gas as a component 2 is advanced through the buffer zone by one or more
 intermittent pulses of compressed gas. Desirably any dissipation means is
 increasingly effective as a component 2 flows through the buffer zone for
 increasingly decelerating the speed of the component 2. Ordinarily, the
 compressed gas is compressed air. The stream of components 2 is advanced
 toward the pickup station 3 by one or more intermittent pulses of
 compressed gas. Some gas pressure is dissipated through holes 7, thereby
 slowing down each component 2 so that the leading component 2 is merely
 nudged out of the tubular buffer zone onto the pickup station 3. The
 pickup zone 3 is open-topped, thus effectively dissipating any residual
 gas pressure.
 The feeder is designed so that the control of the intermittent pulses of
 compressed gas is affected by the situation is the buffer zone. Suitable
 detection means such as optical switches 8 and 9 are actuated to send
 signals to an electronic control device 10 whenever the absence of a
 component 2 is detected by such optical switches 8,9. The electronic
 control device 10 actuates a valve 11 controlling when there should be the
 intermittent pulses of compressed gas. Said valve 11 is ordinarily a
 solenoid valve for ease of electronic control of such pulses.
 In the operation of the feeder, the intermittent pulses of compressed gas
 provides an assuredly reliable but somewhat intermittent stream of
 components 2 to the buffer zone because the intermittent pulses of
 compressed gas urge a component 2 into and through a portion of the buffer
 zone, and then nudge the leading component 2 onto the pick-up station 3.
 Upon the detection of the absence of a component at the light switches 8
 and/or 9, the valve 11 is momentarily opened to send another pulse of
 compressed gas, which gets dissipated through the holes 7 in the
 transparent cover 5, and through the open-topped pick-up station 3.
 The feeder comprises a hopper 12 into which the bulk components 2 can be
 poured through window 13. At the bottom of the hopper 12 is a gathering
 zone of the open-topped groove 6 which slopes downwardly so that whenever
 a component 2 falls into the groove 6, it will flow gravitationally in the
 grove 6, along its downward slope. The gathering zone of such downward
 slope is divided into an upper zone, a middle zone, and a lower zone. In
 order to enhance the potential speed of flow of components 2 through the
 buffer zone, the feeder supplies components 2 for falling into such groove
 6 in the upper, middle, and lower zones of the gathering zone. The bulk
 components 2 in the hopper 12 are randomly oriented. The law of
 probabilities indicates that only a small fraction of the bulk components
 will happen to be so oriented as to fall directly into open groove 6 in
 the upper portion of the gathering zone. The pressure of the bulk
 components above any zone tends to stabilize their orientations. Hence
 many of the components 2 in the hopper 12 above the upper portion of the
 gathering zone will fail to align properly for falling into groove 6.
 Particular attention is directed to a flexible deflector 18 having a
 general L shape, so that when the deflector 18 is flexed, its two edges
 are flexed above the bottom of the hopper 12, permitting components 2 to
 flow gravitationally through openings 19, 20. Thus a group of components 2
 can flow into a zone 21 under the deflector 18. Such components 2 in zone
 21 under the deflector 18 differ from components in the main bulk supply
 in the hopper 12, and are not subjected to as much weight from components
 2 thereabove. Such components 2 in the zone 21 underneath the deflector 18
 have greater freedom from reorienting while flowing gravitationally. Some
 of the components 2 in such zone 21 under the deflector 18 can fall into
 the groove 6 in the middle portion of the gathering zone. Some of the
 components 2 in such zone 21 under the deflector 18 can flow
 gravitationally through an aligning passageway 22 into a transitions zone
 23 of housing insert 24. Some of the components 2 in the transsition zone
 23, having been partially aligned correctly by the aligning passageway 22
 are further aligned by surfaces such as a sloping surface 55 in the
 transition zone 23 so that they are aligned to fall into the groove 6 in
 the lower portion of the gathering zone. Thus it is feasible to apply the
 laws of probability to direct randomly oriented bulk components 2 in the
 hopper 12 into a plurality of portions of the downsloping groove 6 for a
 relatively fast-flowing stream of components 2.
 The components 2 flow gravitationally to a lower curved portion 25 of the
 grove 6, and are lifted through an upwardly sloping lifting portion 26 of
 the groove 6. An upper curved portion 27 of the groove 6 directs the flow
 of components 2 from such upwardly sloping lifting portion 26 to the rear
 of the tubular buffer zone. A gas jet 28 intermittently directs a pulse of
 compressed gas to lift either a single component 2 or a stream of
 components 2 up the sloping lift zone 26 and through the upper curved zone
 27 into and, with appropriate deceleration, through the buffer zone 1.
 Randomly oriented components 2 can bridge zones in such a manner as to
 impair the rapid flow of components toward the buffer zone. A gas jet 29
 sends a dislodging pulse of compressed gas into the transition zone 23 to
 terminate any bridging in the transition zone 23. Gas jet 30 directs a gas
 jet into the zone 21 under the deflector 18 for vibrating the deflector
 18, thereby providing gentle tumbling of the that portion of the hopper
 contents above the deflector 18 without requiring significant consumption
 of power and without excessive abrasion of the components 2 by such gently
 tumbling.
 In the operation of the feeder, bulk components 2 are poured into the
 hopper 12. Some components 2 fall into groove 6 in an upper portion of the
 gathering zone. Some components 2 flow into the zone 21 underneath the
 deflector 18 when the deflector 18 is vibrated by an intermittent pulse of
 gas from jet 30. Some of the components 2 flow from zone 21 into groove 6
 in a middle portion of gathering zone. Some of the components 2 in the
 zone 21 under the deflector 18 flow through an aligning passageway 22,
 thereby being partially aligned into transitional zone 23, where the
 surfaces urge components 2 to fall into groove 6 into the lower portion 17
 of the gathering zone 14. Such alignment techniques provided a greater
 probability that a component in the transition zone will fall into grove 6
 than the small probability that a component would fall into the same
 length of the upper portion of groove 6.
 The stream of components 2 flows gravitationally from gathering zone to the
 lower curved zone 25 of said grooved chute 6. A pulse of compressed gas is
 directed through the lifting jet jet 28 for lifting one or a stream of
 components 2 up an upwardly sloping lifting zone 26 of groove 6 and
 through an upper curved zone 27 into the rear of the horizontal buffer
 zone Gas is dissipated, desirably at an increasing rate, as one of the
 components flows through the buffer zone 1, so that the component 2 is
 nudged onto the pickup station 3 where the component is halted by a hard
 stop 4, which is optionally adjustable. After a light switch 8 or 9 has
 detected the absence of a component 2, the signal is sent to the
 electronic control device 10 which activates valve 11 to send another
 pulse of compressed gas. Such pulse of compressed gas is directed to three
 jets, including said lifting jet 28, dislodging jet 29, and deflector
 vibrating jet 30. After understanding the method, comprehending the
 hardware is easier.
 The feeder includes a housing 31, a front cover 32, and a rear cover 33.
 The feeder has appropriate means for securing the feeder to a companion
 machine such as a robotic assembly machine. A dowel pin 34 and a pin with
 a spherical head 35 and a rib 54 collaborate with a lever 36 and a spring
 37 in positioning the feeder on the machine. The hopper 12 has a loading
 window 13 and front and rear covers 38 which are transparent. The groove 6
 is in a chute-foundation 39, which has the downsloping gathering portion,
 the lower curved portion 25, the upsloping lift portion 26, the upper
 curved portion 27, and the horizontal buffer zone portion. The
 chute-foundation 38 has a general shape with some resemblance to the
 square root symbol in which the two angles are modified into curves having
 a radius of curvature permitting the flow of components 2.
 At the exit end of the feeder is an electrical connector 40 which can be
 energized by an appropriate source of 12 volt DC current. Electrical leads
 41,42 connect the optical switches 8, 9, with the electronic control
 device 10. A red LED 43 and a green LED 44 are actuated by the electronic
 control device 10 in response to signals from the optical switches 8,9, so
 that an operator can determine the status of the feeder. Compressed gas is
 supplied to the solenoid valve 11 through hose 45. A hose 46 directs
 compressed gas from solenoid valve 11 to the three hoses, 47, 48, and 49
 which supply intermittent pulses of compressed gas to jets 28, 29, 30,
 respectively. One or more of the hoses can have an adjusting valve, as
 shown by valve 50 on hose 47 for the lifting gas jet 28.
 2 component
 3 pickup station
 4 not used
 5 transparent cover
 6 groove
 7 holes in transparent cover
 8 rear optical switch
 9 forward optical switch
 10 electronic control device
 11 solenoid valve
 12 hopper
 13 window to pour bulk into hopper
 14 not used
 15 not used
 16 not used
 17 not used
 18 deflector
 19 opening under edge of 18
 20 opening under another edge of 18
 21 zone underneath deflector 18
 22 aligning passageway between 21 & 23
 23 zone within housing insert
 24 housing insert
 25 lower curved portion of 6
 26 upwardly sloping lift portion of 6
 27 upper curved portion of 6
 28 gas jet for lifting through 26 and 27
 29 gas jet for dislodging in 23
 30 gas jet for vibrating deflector 18
 31 housing for feeder
 32 front cover of housing
 33 rear cover of housing
 34 dowel pin
 35 pin with spherical head
 36 lever for mounting feeder
 37 spring for lever 36
 38 side-covers for hopper 12
 39 chute-foundation having groove 6
 40 electrical connector
 41 electrical wire from 8 to 10
 42 electrical wire from 9 to 10
 43 red LED
 44 green LED
 45 hose supplying compressed gas to valve 11
 46 hose from 11 to three hoses 47,48,49
 47 hose to 28 for lifting components through 26
 48 hose to gas jet 29 for dislodging components in 23
 49 hose to gas jet 30 for vibrating deflector 18
 50 adjusting valve 50
 51 not used
 52 not used
 53 not used
 54 rib for mounting feeder