US2868375A - Packaging machine - Google Patents

Description

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PACKAGING MACHINE a bened a'e os/f/veosurcd race 0761 c/oses @zmdwaa PAQKAGING MACH-ENE Thomas P. Howard, Milton, Mass, assi nor to Pneumatic Scale Corporation, Limited, Quincy, Mass, 2: corporation of Massachusetts Application December 9, 1954, Serial No. 474,170

8 (Ilaims. (Cl. 209--121) This invention relates to a packaging machine and more particularly to a weighing machine.

In its broader aspects the invention has for an object to provide a weighing machine having a plurality of continuouslymoving weighing units for forming successive accurately weighed loads and wherein provision is made for first forming a plurality of measured bulk loads and delivering the same to the load. receiving members of successive weighing units and for thereafter delivering a drip stream to the continuously moving weighing units to complete the weighed loads.

The invention has for a further object to provide a novel and improved packaging machine provided with a plurality of continuously moving weighing units ar ranged to deliver successive weighed loads into successive containers moved along therewith and wherein a plurality of measured bulk loads are first formed bycontiuuously moving measuring chambers and delivered to the weighing units and, thereafter a drip stream is delivered to the weighing. units whereby to form successive accurately weighed loads in a rapid and efficient manner.

With these general objects in view and such others as may hereinafter appear, the invention consists in the packaging machine and in the various structures, arrangements and combinations of parts hereinafter described and particularly defined in the claims at the end of this specification.

In the drawings illustrating the preferred'embodiment of the invention:

Fig. 1 is a side elevation of the present paclcagin machine;

Fig. 2 is a plan view of the upper portion of the machine;

Fig. 3 is a cross sectional plan view, as seen fromthe line 33 of Fig. 1;

Figs. 4, and 6 are cross sectional plan views taken on the lines 44, 5-5 and 6-6 respectively of Fig. 1;

Fig. 7 is a plan view detail of shutter opening mechanism and control means for preventing opening of the shutter in the event no container is present, and also illustrating an overweight detecting switch;

Fig. 8 is a similar view showing the parts in a difierent position of operation;

Fig. 9 is a side elevation, partly in cross section, of one of the weighing units embodied in the present machine; I I

Fig. 10 is a plan view partly in cross section of the same;

Fig. 11 is a detail plan view of the shutter latching mechanism showing the shutter in its open or latched position and also illustrating pneumatically operated control mechanism for unlatching the shutter;

Fig. 12 is a similar view showing the shutter in its closed or unlatched position;

' Fig. 13 is a' plan view detail of auxiliary means for unlatching the shutter. to assure closing of the shutter at the start of a new cycle of operation;

Fig. 14 is a perspective view of an underweight detecting switch;

Fig. 15 is a cross sectional view of pneumatically operated control mechanism associated with the weighing units; h

Fig. 16 is a cross sectional view of a portion of the machine including the central rotating shaft and illustrating the vacuum supply lines through the shaft to the several weighing units;

Fig. 17 is a plan view detail of a container engaging switch for detecting the absence of a container in the line;

Fig. 18 is a side elevation of the weighing receptacle and associated mechanism for opening the same;

Fig. 19 is a similarview showing the parts in a dif ferent position of operation;

Fig. 20 is a wiring diagram of a v. circuit which includes signal lamps for indicating an underweight and an overweight container.

Fig. 21 is a wiring diagram of a 220 v. circuit which of Fig. 26 of control mechanism responsive to detection of an underweight container for actuating the containerrejecting mechanism; 7

Fig. 26 is a front elevation of the control mechanism shown in Fig. 25

Fig. 27 is a side elevation in cross section as seen from the line 2727 of Fig. 26;

Fig. 28 is a front elevation of the drives to the control mechanism as seen from the line 28-28 of Fig. 25; and Fig. 29 is a timing chart indicating the sequence of operations in forming, weighing and delivering successive loads into their respective containers.

In. general the, present invention contemplates a novel packaging machine and more particularly a weighing machine having a plurality of continuously moving weighing units for forming successive accurately weighed loads and wherein provision is made for firstforming a plurality of measured bulk loads and delivering the same to the load receiving members of successive weighing units and for thereafter delivering a drip stream to the continuously moving weighing unitsto complete the weighed loads. y The invention is herein illustrated as embodied in a rotary machine of the general type shown and described in the United States patent to Stanley R. Howard, No. 2,678,185, issued May 11, 1954, wherein a plurality of measured loads are formed and delivered into successive containers during the continuous operation of the machine, and in accordance with the present invention a weighing unit is associated with each measuring chamber to receive a measured primary or 'bulk load therefrom, the final or drip load being thereafter delivered directly into the weighing units to complete the weighed loads which are subsequently released into the containers.

In the illustrated embodiment of the invention a generally circular non-rotating feed hopper may and preferably will be divided to provide a bulk load delivery portion 12 and a drip load delivery portion 14 for cooperation with rotary measuring chambers 16 and weighing units 18. In general in the operation of the machine the bulk loads formed in successive measuring chambers are formed and delivered into thereceptacles 26 of corre sponding weighing units 18 during a portion of one cycle or rotation of the rotary units, and the drip loads'in the form of a continuously flowing uniform stream of material are delivered through the open measuring chambers and directly into the weighing receptacles during another portion of said one cycle of rotation. During the succeeding cycle of operation the weighing receptacles are opened to discharge their Weighed loads through guide funnels 21 and into successive containers 22, and simultaneously therewith the measured bulk loads for the succeeding we ghed loads are being formed to be delivered into the weighing receptacles after they have discharged their previously weighed loads and have been again closed. Thus, in operation after the initial cycle of operation to form the first weighed loads, successive weighed loads are discharged into successive containers 22 during the continuous operation of the machine. The weighing units 18 may and preferably will include cantilever spring weighing beams cooperating with pneumatic pressure responsive control units capable of rapid and accurate weighing performance during the continuous movement of the weighmg units.

In general provision is made in the preferred embodiment of the invention for detecting an overweight load and for actuating a-signal to apprise the operator of this condition to be corrected. Provision is also made for detecting an underweight load, and rejecting mechanism responsive to the detector is arranged to subsequently reject a containerwhich-ha's received such underweight load. Provision is also made for detecting the absence of a container 22 in the line. of containers being conveyed into operative relation to their respective weighing units, and control means responsive to suchdetection is arranged to prevent releaseof material to the corresponding weighing unit when no container is presentto-receive theloadh Referring now to Figs. 1 and 3, it will be observed hopper 11B is defined by partition members, 24, 26, 28 and may be supplied with material by gravity through a supply pipe 30. The drip feeding portion 14 of the hopperis defined by partition members 32, 34 and may be provided with material by one or more vibratory feeders 36, 35 arranged to receive the material by gravity through a supply pipe 46 and branch pipes 42, 44 respectively. The vibratory feeders 36, 38 may be of the type capable of feeding a substantially uniform stream of material at a constant rate of speed, and as herein shown, may comprise horizontally extended troughs supported by thin metal straps 46, and each trough is arranged to be vibrated by a vibratory motor 43 secured to a bracket which in turn is attached to a tie piece 52 supported on the upper end of a vertical post 54 extended from the machine frame. The upper stationary structure also includes brackets 56 supported on similar upright posts 58 and which support an upper annular plate 641, a bracket 62 being connected between the plate 61 and the bracket 50. A bracket is also mounted on the upper plate 60. As illustrated in Fig. 20, the vibratory motor 48 may be included in a circuit 49 which may include the variable transformer 53.

As herein shown, the measuring chambers 16 are car-. ried by a rotary member or disk 64 and may comprise telescopically adjustable chambers equally spaced in a circle and mounted to revolve beneath the hopper 1th, the rotary member forming the bottom of the hopper. The upper usual rheostats 51 and portion of each telescopically adjustable chamber 16 may comprise a flanged tube 66 depending from the rotary disk 64, and the latter may be provided with a plurality of rollers 68 arranged to ride on and be supported by a vertically adjustable supporting ring 70. The lower portion of each measuring chamber 16 may comprise a corresponding tube '72 telescopically fitted about the upper tube 66 and supported in a rotary disk 74 secured to a continuously rotated central shaft 76, the telescoping connection imparting rotary movement to the upper portions of the chambers 66 during the operation of the machine.

The containers 22 may be delivered to the machine along a conveyer 78 by an upstanding flexible metal belt 86 having a series of spaced blocks 82 attached thereto between which the cartons are engaged. The belt Ed is arranged to cooperate with a driving pulley 84 fast on the central shaft '7 6 and is arranged to register successive containers in alignment with their respective weighing units. The central shaft 76 may be driven througha worm gear drive 86 connected to a shaft 88 which in turn may be connected to a drive shaft 90 through a second worm gear drive Q2. The drive shaft 90 may be driven by an electric motor 94 belted to a pulley 96 fast on the shaft 9%. The motor 94 may be included in a circuit as shown in the wiring diagram, see Fig. 21. In the operation of the machine the containers may be delivered along the conveyer 78 from a supply thereof, and successive containers are arranged to come into alignment with successive weighing units at the point of tangency with the semicircular path through which the containers are guided in the machine, the containers remaining in alignment with their respective weighing units through 180 and ing ring 70. The screws 101 may be connected to rotate rotation ofthe screws in one direction will effect elevation ofthe upper portion 66 of the measuring chambers to increase the volume, and rotation of the screws in the opposite direction will effect a decrease in the volume. As shown in Figs. 1 and 2, the shaft 109, provided with the bevel gear 107, may be provided with a sprocket 111 forming a part of a chain and sprocket connection 113 to a hand wheel 115 for effecting manual adjustment of the chambers. Thus it will be seen that in operation the supporting ring 70 may be manually raised and lowered, and the upper chambers 66 supported thereby through the rollerconnections 68 are adjusted vertically to vary the volume. It will also be observed that the hopper 10 is supported from the ring 70 by radially extended studs 117 provided with hubs 119 adjustably clamped to upright rods 121 secured to the supporting ring 76, as shown in Fig. 3, so that during adjustment of the chambers 16 the hopper 10 will be moved along in operative relation thereto.

As herein illustrated, each measuring chamber 16 is provided with a bottom closure valve or shutter 1G4, and in the operation of the machine successive measuring chambers 16 are filled .as they pass under the filling or bulk loading portion 12 of the hopper at which time the bottoms of the hoppers are closed by the shutters 104, the latter being thereafter opened to deposit the bulk loads into successive weighing receptacles 20. As shown in Fig. 11, each shutter 104 may be carried by one arm 106 of a two-armed lever pivotally mounted on a stud 168 fast in assass n the rotary dish 74. Each shutter is arranged to be urged into a closed position against a stop 110 by a spring 112 connected to the second arm 114 of the two-armed lever, and each shutter is also provided with a latch 116 arranged to cooperate with a latch member 118 to hold the shutter in an open position. in operation successive shutters 104 are arranged to be opened and latched in their open position at a predetermined point in the cycle of rotation by a cam piece 12% arranged to cooperate with a roller 122 carried by the second arm 114 of each two-armed lever. As shown in'Fig. 7, the cam piece 12+ is pivotally supported in a bracket 124 secured to a tie piece 126, the cam piece being urged to rock in a clockwise direction by a spring 125 connected to an arm 127 extended from the cam piece. During the normal operation of the machine successive rollers 122 in engagement with the cam piece 124? are arranged to urge the pivotally mounted cam piece 126) against a pivotal stop member 128 which forms a part of a control mechanism to prevent opening of a particular shutter when a container is absent in the line, as will be described. Thus, during the normal operation of the machine, successive shutters 104 will be rocked into an open position by the cam piece 121 as the rollers engage therewith to deposit the measured loads into successive weighing receptacles 2t and the shutters will be held in an open position by the latch member 118 during the passage of the chambers through the drip feeding and weighing portion or" the cycle of rotation. The latch member 118 is clamped to a stud 131D carried by a plate 132 extended from each weighing unit 18 and forms a part of the control mechanism arranged to effect release of the shutter to a closed position when a predetermined weight is reached.

Referring now to Figs. 9 and illustrating one of the weighing units 13 disposed beneath each measuring chamber 16, it will be observed that each weighing receptacle 20 is attached to and forms a part of the free end of a cantilever spring beam 134 herein shown as comprising two upper and two lower relatively stifi? cantilever leaf springs 136, 138 of equal length, the leaf springs being connected at their inner ends to a rigid fixed member 140 attached to and extended from an upstanding frame member 142 mounted on a base member attached to an octagonal supporting member 146 keyed to and rotatable with the central shaft 76. The other ends of the leaf springs 136, 138 may be secured to a second rigid member 148 to which the weighing receptacle 2%) is attached by angle straps 1511. The two rigid members 1461, 148

7 together with the leaf springs 136, 138 constitute a four bar linkage so that when a load is placed within the weighing receptacle, the weight thereof results in imparting to the receptacle a straight line motion in a vertical direction so that every particle in the weighing receptacle moves with the same displacement, direction and velocity and so that any particle produces the same spring deflection no matter where it is located in the receptacle. The weighing beam 134 is also provided with a coil spring 152 arranged to exert a counterforce upon the spring beam, the spring 152 being connected at its upper end to a bolt 154 adjustably secured by nuts 1% in a bracket 158 attached to the fixed member 146), as shown in Fig. 9. The lower end of the coil spring 152 may be connected to a rod 160 fast in an arm 162 extending from and integral with the rigid member 148 of the spring beam 134. The rod 161 may extend below the arm 162 and may be provided with a piston 163 operating in oil contained in a dash pot 164 attached to the underside of a bracket 166 mounted on the base member 144. The cantiiever spring beam 134 may be adjustably limited in its upward vertical movement by an upper stop plate 168 carried by an upstanding pin 170 attached to the bracket 166, the plate being engageable with a pin extended from the arm 162, and is limited in its downward movement by'a lower stop screw 172 secured to the base 166 and engageable with the undersurface of the extended portion 162. In practice the coil spring152 serves to counteract the weight of the weighing receptacle 20 and associated parts which are mounted upon the outer ends of the leaf springs, the coil spring 152 being of such strength as to support nearly all of the weight of the measured load being check weighed without deflection of the leaf springs so that the deflection of the leaf springs may be proportionate to the deviation in weight above a predetermined minimum weight limit. For example, a load weight of 15 ounces may be used, and weights above 15 ounces will deflect the leaf springs proportionately to the excess above 15 ounces. A second coil spring 174, adapted for fine adjustment of the weighing unit, is connected at its upper end to an arm 176 extended from the upper end of a rod 1'78 supported in the arm 162, the lower end of the spring 174 being connected to a threaded spring stud 18th cooperating with a bevel gear nut 182 supported in a clearance opening in the base 166. The bevel gear nut 182 is arranged to mesh with a second bevel gear 184 which is arranged to be rotated by a handle 186 to efiect manual adjustment of the coil spring 174 to increase or decrease the tension thereof. The threaded stud may be provided with a key 138 slidable in the base opening to prevent rotation of the stud 180, and a spring pressed ball and socket connection, indicated at 190, may be provided to hold the parts in their adjusted position.

In the illustrated embodiment of the invention provision is made for measuring the deflection of the spring beam 134 when depressed by the load being weighed to indicate the weight of the load. In practice the stiff cantilever springs 136, 138 are selected so that the weighing beam has a relatively small deflection value, and sensitive pneumatically operated control means, indicated generally at 192, is arranged to cooperate with the present spring beam for indicating or measuring the relatively small deflection of the spring beam when depressed by the load being weighed. The pneumatically operated unit 192 is constructed so that a large pressure change occurs upon deflection of the spring beam through a minute distance, and in general the deflection of the spring beam is arranged to increase the pressure in the pneumatically operated unit by an amount proportionate to the deflection.

As shown in Fig. 15, the pneumatically operated measuring unit 192 includes a block 194 having a vertical passageway 196 connected to a regulated source of air under pressure by a pipe 198 and passageway 200, the upper end of the vertical passageway communicating with a horizontal chamber 202 through restricted throat portion 204 arranged to offer a substantial resistance to the flow of air therethrough. The chamber 202, which may be designated as the primary air chamber, in turn communicates with a vertical conduit 206 formed in a jet member 2118 attached to the block 194, the member 208 having a small discharge orifice 210 arranged to cooperate with a valve member 212 carried by the weighing element to be movable therewith. Normally, the valve member 212 is spaced slightly from the orifice 21b, and the construction of the pneumatically operated unit is such that a large pressure change occurs upon minute movement of the valve member 212 toward the orifice 2111 when the weighing element is deflected through a correspondingly minute distance. A second horizontal chamber 214, arranged at right angles to the chamber 206, is connected to an expansible bellows 216 supported in a chamber 218 formed in a laterally extended hollow member 22%, attached to the block 194. The bellows 216 has a substantial area and is urged outwardly by the air pressure in the primary air chamber. A suitable resilient sealing ring 222 is provided in a recessed portion of the member 220 for engagement with the adjacent face of the block to provide a tight seal. The bellows 216 is arranged to cooperate with a piston rod 224 supported for horizontal reciprocation in the member 220 and having an enlarged head portion 226 engageable with the outer face or end of the asses bellows. The rod 224 may be provided with a depending arm 228 fast thereon, the arm extendingthrough upper and lower slots 2% formed in the hollow member 229 for limiting the movement of the rod 224. A spring 232 coiled about the rod 224 and interposed between the arm 228 and an adjustable bearing member 234 supported in the outer end of the hollow member 22%) is arranged to normally urge the rod 224% to the right, movement to the left being effected by an increase in pressure in the chamber 218 to inflate or expand the bellows 216 when the valve member 212 is moved toward the discharge orifice 21%.

As herein illustrated, the lower end of the arm 228 extends through the member 22% and is provided with a valve 236 for cooperation with the orifice 238 of a sec n'l jet member 2-4-4) forming a part of and communicati with a secondary air chamber 242. The air chamber 242 communicates through the chamber 24- with a chamber 246 in a hollow member 243 attached to the upper portion of the weighing unit 18, as seen in Fig. ll. The hollow member 2 8 is provided with a spring pressed rod or plunger 249 for actuating the latch tripping mechanism, indicated generally at 250 in Fig. 11. The lower horizontal chamber 242 communicates with the lower end of the vertical passageway 196 through a restricted throat portion 252, and the chamber 242 communicates with the through passageway sss arranged at right angles to the chamber 24-2, one end of the passageway 24-4 communicating with the orifice 238 in the jet member 244?, and the other end of the passageway 24 5 being connected by a pipe 254 to the chamber 246 of the member 248 and in which the piston 256 of the rod 249 is received. A spring 257 coiled about the rod 24? and interposed between the piston head 256 and a bearing member 258 supported in the hollow member 248 is arranged to normally urge the rod and piston downwardly, and when the jet orifice 238 is closed, as illustrated, the pressure in the chamber 246 is SlllfiClCHl; to retain the piston and rod in its upwardly extended position, as shown.

In operation the valve member 212 carried by the weighing element may be adjusted to normally provide a small space between the valve member 212 and the orifice Zllll when the weighing element is in its elevated position, and upon minute deflection of the weighing element under the influence of the load, the valve 212 is moved toward the discharge orifice 216 a minute amount, thereby effecting a substantial pressure rise in the chamber 214 tending to expand the bellows 216 against the pressure of the coil spring 232. When the pressure in the primary air chamber, acting on the bellows, overcomes the spring the secondary valve 236 is thus moved to the left, viewing Fig. 15, to expose the opening 238 in the jet 2 th, thus reducing the pressure in the chamber 246 and permitting the spring 257 to move the piston rod 249 downwardly to trip the material feed control latch and terminate the feeding of material into the weighing receptacle 29 when a predetermined weight is reached.

As illustrated in Fig. 16, the weighing units 13 are supported on the individual base members 144 secured to the rotary supporting member 146, and the inlet pipe 193 of each pneumatically operated unit 192 is connected to a chamber 2th formed in a hollow member 2&3 sccured to and rotatable with the central shaft 76. The

chamber Ztll is arranged to communicate with horizontal passageways 2% and a central vertical passageway 2'37 formed in the continuously rotated central shaft '76. The upper end of the shaft '76 is supported in the bracket 55 and is provided with a reduced end portion extended into a hollow member 2% secured to and rotatable with the shaft 76. The upper end of the central passageway 24W opens into a chamber formed in the hollow member 269, the chamber being in airtight engagement with a central opening formed in a stationary bearing member 211 mounted within the hollow portion of acap member 213 secured to the upper frame structure. A sealing ring 215 carried in a grooved portion formed in the cap member 213 is arranged in airtight relation with the periphery of the bearing member 211, and a passageway 217 formed in the upper end of the cap member 213 is connected by a supply pipe 219 to the source of air, thereby enabling the pneumatically operated units 192 to be supplied with air during the continuous rotation of the weighing units 18 with the shaft '76. As shown in Fig. 16, the bearing member 211 is movable vertically in the cap member 213 relative to the sealing ring 215 and is retained in airtight engagement with the upper surface of the rotating hollow member 209 by compression springs 221 interposed between the underside of the cap member 213 and the top of the bearing member 211.

Refs now to Figs. 11 and 12 illustrating the latch tripping mechanism 25b for terminating the feed of the material when a predetermined weight is reached, it will be observed that the piston rod 249, forming a part of the pneumatically operated pressure responsive control means 192, is arranged to cooperate with the outer end of a latch releasing arm 26b pivotally mounted on the stud 13b and which is adapted to release the shutter 104 to cut off the drip stream passing through the measuring chambers 16 when the predetermined weight is reached. The arm 26%} is maintained in engagement with the end of the rod 249 by a spring 262 and is also provided with an adjustable stop screw 26d engageable with an arm 266 clamped to the latch stud 13s to which the latch member 1155 is clamped. A spring 268 connected to the arm 266 is arranged to maintain the same in engagement with the stop screw 264 carried by the arm 260. In the normal operation of the machine when the pressure in the member 24% is decreased, as described, to permit the rod 24? to move inwardly, the latch member 118 is rocked in a counterclockwise direction to release the shutter arm res and cut off the feed through the chamber 16, as illustrated in Fig. 12.

In the event that insufiicient material has been introduced into the weighing receptacle 20 to reach a predetermined weight during the weighing period in the cycle of operation, auxiliary means is provided for mechanically closing the shutters as the weighing units approach the end of the weighing period in order to assure closing of the chambers at the start of a new cycle of operation when the weighing receptacles are opened to discharge their weighed loads into the containers. As illustrated in Pig. 4 and in detail in Fig. 13, this may be accomplished by a second arm 2'70 clamped to the stud E38 and which is arranged to engage a roller 272 carried by a bracket 2'74 attached to a tie piece 276. In operation when the arm Z'Ftl engages the roller 272 the latch member will be rocked in a counterclockwise direction to effect release of the shutter 184 independently of the pneumatic control unit 192. As will be hereinafter described, provision is made for detecting such underweight load and for subsequently rejecting a container into which such load has been discharged.

From the description thus far and by reference to the timing chart shown in Fig. 29, it will be seen that in the operation of the machine the measuring chambers 16 are closed at the beginning of a cycle of operation and are filled as they pass under the bulk loading area of the hopper ltl whereupon the chambers may be opened to deposit the measured leads into the receptacles 2b of successive weighing units 18. Thereafter, the measuring chambers remain open as they pass under the drip feeding area of the hopper it and when a predetermined weight is reached the pneumatic control unit 192 effects closing of the shutter to cut off the drip stream.

Referring now to 16, it will be observed that each weighing receptacle 26 is provided with a bottom closure gate 28% pivotally mounted at 232 and normally maintained in its closed position by a spring 284. Provision is made for opening the gate 280 of each receptacle at the beginning of a cycle of rotation to eifect discharge of the weighed load into a container 22, and as herein shown, each gate is provided with a cylindrical extension 286 at its inner end arranged to be engaged by a vertically reciprocable rod 288 slidingly supported in a U- shaped bracket 290 carried by each weighing unit. The rod 288 is arranged to be reciprocated by a stationary cam 292 which surrounds the central rotary shaft 76 and is supported in a fixed position by a bracket 294 secured to a fixed portion of the machine. As herein shown, the lower end of the rod 283 is connected to one armof a bell crank 296 pivotally mounted on a stud 298 carried by a bracket 300 secured to the underside of the bracket 146. The other arm of the bell crank is provided with a roller 302 cooperating with the cam 292, and a' spring 304 serves to hold the roller against its cam. The rod 288' is normally urged downwardly as shown in Fig. 18 by a coil spring 306 interposed between a collar 3% fixed on the rod 288, and a loose collar 31% arranged to cooperate with the underside of the upper leg of the U-shaped bracket 2 90. The earn 292 is arranged to effect elevation of the rod 288 at the beginning of a cycle of operation to open the gate 280, as shown in Fig. 19. Simultaneously with the gate opening operation, provision is made for locking the weighing beam 134. As herein shown, an intermediate shouldered portion of the loosely mounted collar 310 is normally maintained out of engagement with the underside of the upper leg 312 of the U-shaped bracket by a spring 314 interposed between the underside of the leg and a flange formed on the collar 310. As shown in Fig. 18, at this time the upper end of the collar 310 is also maintained out of engagement with the head of a stop screw 316 adjustably carried by the angle strap 150. In operation upon initial elevation of the rod' 288, the spring 306 is arranged to overcome the spring 314 so as to move the collar 310 to present the intermediate shoulder in engagement with the underside of the leg 312 at which time the upper end of the collar 310 engages the stop screw 316 to maintain the weighing beam in a locked position. Thereafter, the rod 288 will slide through the collar 310 to engage the cylindrical extension 286 and effect opening of the gate 230.

Thus in the operation of the machine it will be seen that at the start of a cycle of operation the bulk loads for the succeeding weighed loads are being formed in the chambers 16 while the gates 286 of the weighing receptacles are open to discharge the instant weighed loads into the containers, and the gates remain open for a predetermined portion of the cycle whereupon the gates are closed in readiness to receive the bulk loads being formed. It is preferred to maintain the weighing beams 134 in their locked position when the bulk loads are discharged into the closed weighing receptacles, the cam 292 being designed to maintain the rod 288 in an intermediate position, as shown in Figs. 9 and 16, wherein the weighing beam 134 is locked and the gate 280 is closed. As indicated in Fig. 29, immediately after the bulk loads are deposited into the weighing receptacles 20, the weighing beam 134 may be unlocked by the cam 292 to perform the weighing operation, the weighing beam being again locked at the start of a new cycle of operation and the receptacle gates opened to discharge the loads into the containers as described.

The description thus far relates to the normal operation of the machine, and as herein shown, provision is made for detecting the absence of a container in the line being conveyed into the machine and for preventing introduction of material into the weighing receptacle 20 which would normally discharge its load into such container. As illustrated in Fig. 6 and in detail in Fig. 17, a detector arm 320 pivotally mounted at 322 is arranged in the path of the incoming containers on the conveyer 78 and is urged in a counterclockwise direction against the sides of the containers by a spring 324. The

engaging face of the arm 320 is of sufficient length to straddle the space from the trailing edge of one container to the leading edge of an adjacent container when a continuous supply of containers is advanced so that normally the arm will remain in the full line position shown in Fig. 17. However, in the event a container is absent the arm 320 will be rocked by the spring 324 to the dotted line position to actuate a switch 326 in a circuit 328, see Fig. 21, which also includes a solenoid 330 arranged to trip the pivotal stop member 128 and release the pivotally mounted cam piece 120, as shown in Fig. 8. The solenoid 330 is connected to an arm 332 fast on a stud 334- on which the stop member 128 is mounted, and the stop member is urged into latching relation to the cam piece by a spring 336. Thus in operation, when the solenoid 330 is energized the stop 12% will be rocked in a counterclockwise direction to release the cam piece 120 which will be rocked outwardly by engagement of a cam roll 122 therewith. The cam piece 120 is subsequently rocked inwardly or in a clockwise direction to permit latching engagement with the stop member 128 by the spring 125. As a result of releasing the cam piece 120, as described, the shutter 104 above the receptacle 2% associated therewith will remain closed during-the remainder of the cycle of operation so that when the receptacle is opened at the start of a new cycle of operation in alignment with the space normally occupied 'by the absent container, no material will be discharged therefrom. As shown in Fig. 6, the detector arm 320 is spaced a distance of five containers preceding the point of tangency of the container with the rotary portion of the machine which corresponds to the number of stations between the cam piece 121) and said point of tangency so that the empty receptacle will register with the space normally occupied by the absent container. The previously filled chamber 16 may then again pass through the bulk feeding portion of the cycle and resume normal operation.

Referring now to Figs. 7 and 29, in the event that the weighing beam 134 is stripped immediately after the weighing beam is unlocked so as to effect closing of the shutter 1% before the measuring chamber 16 enters the drip feeding area, such action indicates an overweight load, and provision is made for detecting such condition. As herein shown, a detecting finger 340 pivotally mounted at 342 is arranged to be engaged by the roller 122 of a shutter 104 when the latter is closed at such time, as indicated in dotted lines in Fig. 7. Normally, when the shutter 104 remains open the roller 122 will pass the detecting finger without engaging the same. The detecting finger 34-0 is urged inwardly by a spring 344 and is provided with an arm 346 arranged to actuate a switch 342-3 when the detecting finger is rocked outwardly by the roller 122. As shown in Fig. 20, the switch 348 forms part of a circuit 350 which includes a signal lamp 352 to apprise the operator of such abnormal condition so that he may eifect manual adjustment of the chambers to reducethe volume, as described.

Provision is made in the preferred embodiment of the invention for detecting an underweight load deposited in a receptacle 20 and for subsequently rejecting the container into which such underweight load has been discharged. As hereinbefore described, in the normal operation of the machine the shutter 104 remains open, as shown in Fig. 11, until a predetermined weight is reached in the receptacle 2t whereupon the shutter 1114 is automatically released to cut off the feed of the material into the receptacle, as shown in Fig. 12. It will be observed that the shutter 1114 is provided with an extension 35 1 arranged to engage one end of a spring pressed pin 356 slidingly mounted in a bracket 358 movable with and supported on top of each weighing unit 18. The outer end of the pin 356 is provided with a roller 360 arranged to engage and close an underweight detecting switch 362 when the roller is maintained in an

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