Patent GB-824857-A (GB)
Title: Apparatus for feeding loose bulk material
IPC: A24C5/39
Filed: 1956-05-30
Abstract: 824,857. Cigarette-making machines. PROCTOR & SCHWARTZ Inc. May 30, 1956 [June 7, 1955], No. 16714/56. Class 130. [Also in Group XXX] Tobacco is fed to a plurality of supply hoppers 32-36, each supplying a cigarette-making machine by a series of overlapping endless belt conveyers 38-42 having their rear ends overlying respective hoppers 32-36, each conveyer being driven independently by a reversible electric motor, the various motors being controlled by an electric circuit which causes each conveyer in turn to deposit an increment of tobacco in the respective hopper so that the increments of tobacco are fed in predetermined timed sequence to the hoppers in repeated cycles until a desired supply has accumulated in at least one of the hoppers, whereafter the feeding is interrupted to the hoppers wherein the desired supply has accumulated while continuing the incremental sequential feeding to the remaining hoppers. The system of conveyers, which includes master feed conveyers 30 and 31, operates in two phases, alternate cycles being phase 1 while the remainder are phase 2. Fig. 2 shows phase 1 in operation in which each conveyer in turn is given two movements, being first driven in reverse whilst at the same time the preceding conveyers and master feed conveyers are driven forwardly and then being driven forwardly together with the preceding conveyers. At the end of this cycle, Fig. 6, all the hoppers have received one increment of material (assuming they were originally empty) whilst each conveyer is loaded with a second increment of material. All the conveyers are now stopped and phase 2, Fig. 8, commences. In phase 2 the master feed conveyers 30 and 31 remain stationary throughout whilst each of the conveyers 32-36 is driven in turn in reverse to deposit its load into the respective hopper. The two phases are then repeated in the next two cycles, and so on until at least one of the hoppers, e.g. hopper 33, Fig. 15, is full whereupon a high-level switch 43 is closed. When this occurs all the conveyers are stopped during the period when the respective conveyer 39 should be moving rearwardly irrespective of whether phase 1 or phase 2 is in operation, so that feeding to the full hopper is skipped during that cycle. Fig. 15 shows also hopper 35 to be full in which case its high-level switch 44 is also closed and feed to this hopper is also skipped during that cycle. The feed to the full hoppers is skipped during as many cycles as the highlevel switches of three hoppers remain closed. In the case of a high-level switch being closed during a phase 2 cycle and re-opened during a phase 1 cycle two increments of material will be fed to that hopper during the phase 1 cycle since the associated conveyer already carries a load of material. This is said not to affect the balance of the system. The electric control circuit, Fig. 25, comprises a main switch 102 which when operated energizes relay UV to energize switches 104, 117 and 124. To start the system switch 104 is first closed to supply power to a photo-cell 115 and associated amplifying circuit via a transformer 114 and to illuminate a lamp PL whose circuit is completed via contacts 107 of a relay controlled by the photo-cell. The photo-cell is acted on by a beam from a lamp 112 also illuminated by closing switch 104. When the photo-cell circuit has warmed up contacts 107 open to extinguish lamp PL indicating that switch 117 can be depressed to start the main feed by energizing main feed relay MF via safe-run switch 103, contacts of a relay SR energized by closure of switch 104 and contacts 121 which were closed when contacts 107 opened. The light beam from lamp 112 is positioned across the delivery end of conveyer 31 and when broken by the arrival of tobacco causes contacts 121 to open to stop the feed. This photo-electric control is no longer necessary so switches 104 and 117 are now opened and switch 124 is closed to commence automatic operation. A further photo-cell may also be provided, however, for actuation during automatic operation to cut-off all the conveyers if the tobacco should reach the delivery end of the last conveyer 42. In automatic operation control is effected by a series of cams TC-1 to TC-5, PC-1 to PC-5, FMC, SOC and FS mounted on a common shaft 128 driven by a motor 127 energized by the switch 124. The main feed is operated during phase 1 by cam FMC closing contacts 150 to energize relay MF. The circuit to relay MF is completed through contacts of a relay MR which, when energized through closure of contacts 182, 183 by cam SOC at the end of each phase, stops all the conveyers, since its contacts are also in circuit with relays CF-1 to CF-5 controlling forward movements of the conveyers 38-42, respectively, and with relays CR-1 to CR-5 controlling rearward movements of these conveyers. In normal operation the relays CR-1 to CR-5 are operated sequentially over each of two 15 degree arcs of their respective cams TC-1 to TC-5 through closure of the lower pair of contacts of each of the sets of contacts 135, 145, 146, 147 and 148 controlled by these cams. This causes the associated conveyers to move sequentially rearwardly once in each of the two phases. Between the two 15 degree arcs mentioned above on one side of each cam is a raised portion which causes closure of the upper pair of contacts of the sets of contacts 135, 145, 146, 147 and 148 to operate the relays CF-1 to CF-5 sequentially to provide the forward movement of the conveyers 38-42 during phase 1 only. During phase 2 forward movement of conveyers 38-42 is prevented by cam FS opening contacts 157 in the circuit of a relay FS whose contacts are thereby opened to break the circuit to all of the forward speed relays CF-1 to CF-5. In order to prevent feed to a hopper which is full relays REL SUB-1 to REL SUB-5 are provided having. contacts in the circuits of relays CR-1 to CR-5 respectively and controlled by high-level switches HL-LS1 to HL-LS5 in the respective hoppers 32-36 so that if any of these switches are closed the corresponding conveyer is prevented from moving rearwardly. Manually-operated switches SW-1F to SW-5F are provided in parallel with the high-level switches for use where a machine is to be shut down. In a modified construction, Fig. 26, two series of overlapping conveyers 306, 307 are provided to supply two rows of machines and are adapted to be fed alternately with tobacco from a master feed conveyer 300 by alternate operation of transverse feeder conveyers 302, 303, the arrangement being such that one of the series of conveyers is receiving tobacco from the master feed conveyer 300 during operation of phase 1 while the other series of conveyers is operating in phase 2. The master feed conveyer 300 may he driven through a variable speed drive controlled by accumulated data signalled by the operation of the highlevel switches and/or further low-level switches in the hoppers.