Vibrating conveyor with distribution channel switching system

A vibrating conveyor having a circular or helical conveying conduit driven with a vibrating motion by way of an electromagnet having alternating voltage. The conveying conduit emerges, at its end, into an overflow chute constructed in the form of a channel switching system. An overflow channel oscillates with a reciprocating motion about a pivoting shaft. Mechanical and electrical control devices are provided, so that the overflow channel can be brought into variable oscillating positions. The overflow channel includes a U-shaped section, pressing radially on a sliding surface, forming a circular zone and fixed on a pivoting shaft mounted on the sliding surface. This section is driven by a reciprocating motion in the peripheral direction of the circular zone about the pivoting shaft. Through the pivoting shaft, this section is rigidly connected to a guide rail open downwardly, arranged beneath the sliding surface and extending parallel thereto. In this guide rail is housed a cam, which is set on a control disk, arranged parallel to the sliding surface, such that when the control disk is driven in rotation by an electric motor, the cam causes the guide rail to oscillate with a reciprocating motion and, thus, the overflow channel above the sliding surface.

This invention relates to a vibration conveyor as used in a variety of
 embodiments for conveying small parts. Vibration conveyors of this type
 work on the principle that a spiral or circular-shaped track is made to
 vibrate, with the movement essentially comprising a horizontal and a
 vertical component. The material to be conveyed may be small parts made of
 highly varied materials, which have to be e.g. sorted, inspected, cleaned
 and filled into drums as part of a production process. Sorting pots driven
 in this manner cause the small parts inside to move around the edge of the
 sorting pot, with only those small particles that find themselves in a
 certain position being able to negotiate a corresponding sorting passage,
 whilst the others fall back into the sorting pot. Another special version
 of a vibration conveyor serves to simultaneously smooth and remove dust
 from pharmaceutical products such as tablets or pills. Vibrations
 conveyors of this type are fitted with a drive unit consisting of an
 electromagnet to which alternating voltage is applied. On top of the
 electromagnet there is a vibration plate, to which the parts of the
 vibration conveyor that are to be made to vibrate are securely attached.
 On the opposite side of the electromagnet there is a suspended
 complementary vibration plate, on which the electromagnet is vertically
 adjustably attached, with the vibration plate and the complementary
 vibration plate being elastically connected to each other. This elastic
 connection can consist, for example, of leaf spring sets disposed at an
 oblique angle to the winding axis of the electromagnet so that when the
 vibration plate is made to vibrate, it receives both a vertical and
 horizontal vibration component. The base construction is connected to the
 vibrating part solely by means of the vibration nodes of the leaf spring
 sets, and so the base construction remains stationary in operation and is
 not exposed to any vibration.
 Such prior art vibration conveyors have a dispensing chute through which
 the conveyed parts fall into a drum. In practice, the drum is placed under
 the dispensing chute on a weighing device and filled up until the target
 weight is achieved, or the drum is filled up to a visual level indicator
 mark. The vibration conveyor is then switched off, or the dispensing chute
 is blocked until a new, empty drum can be positioned. Sometimes, several
 drums are arranged next to each other and a swivelling funnel device into
 which the small parts fall as they leave the dispensing chute is moved by
 hand from one drum to the next as each drum fills up with the vibration
 conveyor in operation all the time. After filling a number of drums, e.g.
 enough to load on a pallet, the vibration conveyor has to be switched off,
 the pallet with the full drums has to be removed, and another pallet with
 empty drums repositioned under the dispensing chute. With the increasing
 automation of the process of transferring small parts to containers it
 would be preferable to organize the filling up of individual drums without
 any manual intervention.
 Hence it is the task of this invention to provide a vibration conveyor with
 a device for automatically filling up several containers.
 This task is solved by a vibration conveyor with a spiral or
 circular-shaped conveyor channel which can be made to vibrate by means of
 an electromagnet under alternating voltage and whose end opens out into a
 dispensing chute, it being characterized in that the dispensing chute is
 contrived as a distribution gate which comprises a dispensing channel that
 can be moved to and fro around a pivot axis by an electric motor, with
 mechanical and electrical control means for guiding the dispensing channel
 to different positions in line with a control program.
 An advantageous embodiment of this vibration conveyor with distribution
 gate is illustrated in the drawings; it will be described below with
 reference to these drawings, and the function of the individual parts will
 be explained and commented on.

FIG. 1 shows the vibration conveyor 1, which has here an upwardly disposed
 spiral-shaped conveyor channel 2, which is encased by a cylindrical
 perspex jacket. Underneath the perspex jacket is the drive unit 3 with the
 vibration plates connected via leaf spring sets and the electromagnet
 disposed between these vibration plates on the lower vibration plate, to
 which alternating voltage is applied to make the two vibration plates
 vibrate with horizontal and vertical components. Conveyor channel 2 is
 secured on top of the upper vibration plate. The housing of the drive unit
 3 and the perspex jacket of the conveyor tower remain vibration-free
 because they are only connected to the vibration plates and the
 electromagnet via the vibration nodes of the leaf spring sets. The small
 parts enter vibration conveyor 1 via the feed pipe 4. They slide through
 the inlet chute 5 into the conveyor channel 2, on which they move upwards
 as it oscillates and. vibrates. If said small parts are e.g. tablets, they
 are simultaneously smoothed and the resultant dust is sucked away, via a
 central extraction system, through a perforated pipe around which runs
 conveyor channel 2. During the conveying process the small parts move
 through a height equal to the vertical elevation between the inlet chute 5
 and the inlet edge of the dispensing chute 6. From this point they are to
 be automatically targeted in pre-programmed volumes into waiting drums 9.
 For this purpose dispensing chute 6 is contrived as a distribution gate.
 In the example illustrated, the small parts can be guided through four
 separate outlets 7 into any one of the filler hoses 8 which guide the
 small parts into a waiting drum 9. This process of distributing specific
 volumes of small parts into different drums 9 is performed automatically
 by the distribution gate 6 which can be programmed and operated by an
 electric motor.
 FIG. 2 shows this distribution gate 6 on its own. It has a circular
 segment-shaped smooth surface 10, preferably made from a chromium steel
 sheet, which terminates here on both sides in an edge 11 that is bent
 vertically upwards. Attached to the front end there is an edge 12 with
 several outlet holes 13, to each of which is attached a sleeve 14 for
 connecting a filler hose. Edge 12 overlaps smooth surface 10 downwards,
 and the outlet holes 13 are arranged so that smooth surface 10 finishes up
 at about the same height as their horizontal diameter. As can be seen in
 FIG. 1, the overall distribution gate 6 is attached to vibration conveyor
 1 in a downwardly inclined position. Lying on top of smooth surface 10
 there is a dispensing channel 15 in the form of a U-profile made of
 chromium steel or plastic. At the top, it is pivotably attached to the
 chromium steel sheet forming smooth surface 10 via an axis 16 that is
 rigidly connected with it. This allows dispensing channel 15 to be pivoted
 around axis 16 so that its lower end can be moved in front of any of
 outlet holes 13 as required. Hence the small parts that slide down from
 the top through dispensing channel 15 travel through the selected outlet
 hole 13 into the connected filler hose 8, as shown in FIG. 1.
 FIG. 3 shows an example of an embodiment for the drive and control
 mechanism for operating the distribution gate. This Figure shows the
 elements of the distribution gate below smooth surface 10, which is only
 indicated here by a dashed line. Dispensing channel 15, which is only
 partly drawn in here, lies on top of this smooth surface 10. This
 dispensing channel 15 is pivotably attached to smooth surface 10 via
 co-rotating axis 16. Running parallel to dispensing channel 15 underneath
 smooth surface 10, there is a guide rail 17, which is also rigidly secured
 to axis 16 so that its pivoting movement around axis 16 is conveyed via
 the latter to dispensing channel 15. This guide rail 17 consists of a
 U-profile made from chromium steel or plastic which is integrated such
 that it is open facing downwards. Lying underneath guide rail 17, a
 control disk 18 is rotatably mounted around an axis 19, with this axis 19
 being mounted in an assembling sheet 20 that lies underneath control disk
 18 and runs parallel to smooth surface 10. Axis 19 is driven by an
 electric motor which is attached to the underneath of assembling sheet 20
 and is not visible here. At its periphery, control disk 18 has a cam 21
 which fits inside the inside width of the U-profile that forms guide rail
 17. When control disk 18 rotates, cam 21 circles round the central axis 19
 of control disk 18, carrying guide rail 17 along with it, which in turn
 carries dispensing channel 15 along with it via pivot axis 16. To stop
 dispensing channel 15 precisely in front of whichever outlet hole 13 is
 required, several recesses 22 are contrived around the periphery of
 control disk 18. A contact rocker 23 is pivotably mounted on assembling
 sheet 20 in the plane of control disk 18 by means of axis 24. At its front
 end, the contact rocker 23 has a roller 25 which rolls along the
 peripheral surface 26 of control disk 18 when the latter rotates. A spring
 27 ensures that the front end of contact rocker 23 with the roller 25 is
 kept pressed against the peripheral surface 26 of control disk 18. The
 roller 25 on the contact rocker 23 falls into each recess 22 it reaches as
 control disk 18 rotates. The resultant pivoting movement of contact rocker
 23 causes its rear part 28 to pivot outwards. This in turn closes an
 electric contact 29 on switch 30. The sequence of the contacts that take
 place as control disk 18 rotates corresponds to the individual positions
 of dispensing channel 15. Using an associated memory-programmable electric
 control device (SPS) a program can be set to define e.g. how long a
 certain position should be maintained, to which outlet hole 13 dispensing
 channel 15 should then be pivoted by rotating control disk 18 with the
 electric motor, how long it should remain there, and which outlet hole 13
 it should be directed to afterwards etc. The program can e.g. be
 configured to serve the four outlet holes 13 shown in FIG. 1
 consecutively, and to have dispensing channel 15 remain for a set time at
 each outlet hole 13, or until an external signal supplies the impulse to
 pivot dispensing channel 15 into its next position. An external signal of
 this type can come e.g. from a weighing device on which the drum being
 filled is positioned, which sends an impulse to the SPS of the
 distribution gate once a certain target weight has been achieved. The
 signal could also be supplied from an optical detector which measures the
 fill-level of the individual drums. This allows one to program a
 distribution cycle for continuously filling one drum, after which an
 immediate start is made on filling the next awaiting drum so that the
 positioning and removal of the drums can take place automatically on a
 conveyor belt, or the full drums can simply be replaced with empty ones by
 an operator. The SPS can be programmed to e.g. switch off the vibration
 conveyor when the signals from the weighing device or the optical detector
 indicate that every drum is full.