US 3263712 A
Description (OCR text may contain errors)
E. M. LAU
Aug. 2, 1966 BAG ACTUATED SWITCH MECHANISM FOR BAG FILLING MACHINE 5 Sheets-Sheet 1 Filed June 10, 1963 Au 2, 1966 E. M. LAU 3,
BAG ACTUATED SWITCH MECHANISM FOR BAG FILLING MACHINE Filed June 10, 1963 3 SheetsSheet 2 r 0 j i -4--- 4 P157 v i T L g i .53
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Erwin j flau Aug. 2, 1966 M E. M. LAU
BAG ACTUATED SWITCH MECHANISM FOR BAG FILLING MACHINE Filed June 10, 1963 5 Sheets-Sheet 5 i F r f K a United States Patent Office 3,263,712 Patented August 2, 1966 Erwin M. Lau, Bolton, 11]., assignor to Black Products Co., Chicago, ., a corporation of Illinois Filed June 10, 1963, Ser. No. 286,761 7 Claims. (Cl. 141-68) This invention relates to an improved starting arrangement for a bag filling machine of the automatic cut off type.
A bag filling machine of the automatic cut off type includes a scale mechanism which, by means of an operating circuit, operates to discontinue the feeding operation when the material which is being fed through the spout into the bag reaches a predetermined weight. The invention is applicable to bag filling machines having various types of feeding mechanism, but is illustrated herein as applied to a machine of the fluidizing type as shown in my prior Patent No. 2,963,994, granted May 17, 1960.
The object of my invention is to provide a machine in which the placing of the bag on the spout automatically starts the filling cycle.
The problem encountered in such an arrangement is that when removing the bag from the spout, any inadvertent movement of the spout, which at this time is in balance, will again close the scale actuated operating circuit to feed material through the spout as the bag is being removed.
The present invention provides a bag actuated switch and overcomes the above difficulty by associating the switch with the bag clamp of the machine and with a starting relay so that the operation of the bag clamp pursuant to the closing of the bag actuated switch will restore the switch to its open circuit condition and will cause it to remain in such condition even after the release of the bag clamp. Thus, the bag actuated switch can be connected to the starting relay of the operating circuit and serve as the start switch for the operating circuit, functioning in the same manner as the start button of the starting relay, and the bag actuated start switch may be substituted for the start button or connected in parallel therewith.
Another object is to provide improved switch actuating mechanism which includes a shoe which is engaged and displaced by the edge of the bag wall as the bag is slipped on to the spout, but in which the cooperation of the shoe, the bag wall, and the spout does not prevent reverse movement of the shoe while the bag is still in place.
Other objects, features and advantages will become apparent as the description proceeds.
With reference now to the drawings in which like reference numerals represent like parts:
FIG. 1 is a view of a portion of the bag filling machine embodying my invention;
FIG. 2 is a side elevation on a larger scale of a preferred embodiment of my invention;
FIG. 3 is a vertical section taken along line 3-3 of a FIG 2 showing the bag clamp;
FIG. 4 is a vertical section taken along line 44 of FIG. 2 showing the bag actuated start switch and associated mechanism;
FIG. 5 is a plan view taken along line 55 of FIG. 2;
FIG. 6 is a wiring diagram illustrating the operation;
FIG. 7 is a fragmentary side elevation similar to FIG. 2 but showing a modification;
FIGS. 8 and 9 are views similar to FIG. 2, but showing the rock arm assembly in changed positions, and also showing a modified form of the stop for the switch plung- FIG. 10 shows a modified bag clamp yoke.
is mounted in the stop 40 for adjustment purposes.
FIG. 1 shows a bag filling machine which includes a supporting framework 10, a fluidizing chamber 11 having an outlet at its lower end which communicates with the bag filling spout 13 by means of a flexible tube 12. The bag filling machine also includes scale mechanism 14 and suitable spout supporting mechanism 15 provides a connection between the spout 13 and the scale mechanism 14.
The feeding operation is discontinued by an air operated pinch valve 16 which cooperates with the flexible tube 12.
In operation, a valve bag 17 is placed on the spout; when the cycle of operation is started, the material within the fiuidizing chamber 11 is fluidized and will flow in a horizontal direction through the spout 13 and into the bag 17. When the weight of the bag and contents reaches a predetermined amount, such as pounds, the scale mechanism 14 is tripped, and the air operated pinch valve 16 engages the flexible tube 12 to cut ofii the flow of materlal through the spout 13 in order to terminate the bag filling operation.
A bag clamp 18 is provided to maintain the bag in position on the spout, and the arrangement is such that the bag clamp is automatically released at the end of the filling cycle to permit removal of the bag from the spout.
As shown in FIG. 2, the spout supporting mechanism 15 includes a vertical plate 20 which carries a bracket 21. The bag clamp 18 comprises an air cylinder 22 having a piston 23, the air cylinder being mounted in bracket 21. A shaft 24 is journaled in the bracket arms and a clamp arm 25 is secured to the shaft 24. A yoke 26 is mounted on the outer end of the clamp arm 25 and includes rubber gripping pads 27 which are located above the spout.13 and normally spaced therefrom. However, when the air cylinder 22 is operated, the piston 23 is extended and bears against the clamp arm 25 by means of a roller 28, and urges the yoke 26 downwardly into engagement with a bag which has been placed over the spout. A spring 29 extending between a spring bracket 44 and the mounting bracket 21 urges the clamp arm 25 upwardly.
The bag actuated start switch mechanism includes a rock .arm assembly 30 which is pivotally mounted on the bracket 21 by a pivot pin 31. A microswitch 32 is supported in the upper end of the assembly 30, and is provided with the usual switch plunger 33 which projects horizontally and toward the air cylinder 22. The rock arm assembly 30 comprises a pair of arms 34 which extend downwardly below the pivot pin 31 and which carry at their lower ends a pair of shoes 35 which are shaped, as shown in FIG. 5, to correspond with the surface configuration of the spout 13 at that particular point. In the embodiment shown, the spout 13 may have a tapered portion 36 which provides a tight engagement with the opening or valve of the bag, and as shown in FIG. 5, the arms 34 are slightly twisted so that the surface of each shoe 35 will be more or less parallel to the taper of the spout. The front edge of each slice may be flared as at 37 to facilitate the insertion. of the bag wall into the clearance 38 between the shoe and the spout, thus rocking the cradle assembly 30 in the counterclockwise direction, as viewed in FIG. 2.
As shown in FIG. 2, an abutment or stop 40 is mounted on bracket 21 in front of the plunger 33. A set screw 41 Thus when the rock arm assembly 30 is tilted, the plunger 33 will be depressed to close the microswitch 32. This causes operation of the bag clamp, the piston 23 moving downwardly and depressing the clamp arm 25.
The downward movement of the clamp arm 25 is utilized to restore the rock arm assembly 30 to its initial position. As shown in FIG. 2, a striker arm 42 is secured to each end of the shaft 24 and rotates therewith. When the clamp arm 25 moves downwardly, the striker arms 42 engage the arms 34 of the rock arm assembly 30 to restore the latter to its normal position, thus again opening the microswitch 32. A crosspiece 45 limits the position of the assembly 30 in the clockwise direction.
An alternative construction is shown in FIG. 7 in which the start switch 32' is mounted on the bracket 21, and the rock arm assembly includes a cross arm 43 which engages the plunger 33 through a suitable set screw 41.
The circuit illustrating the operation is diagrammatically shown in FIG. 6. Here the reference numerals 50 and 51 illustrate the leads to a source of power, the lead 51 being shown as grounded for purposes of clarity. Connected across leads 50 and 51 is a solenoid valve 52 which controls the air supply to the air cylinder 22 and a solenoid valve 53 which controls the air supply to the pinch valve 16. Various other control mechanisms, not shown, may be connected across the leads 50 and 51 in a similar manner.
A microswitch 54 and a starting relay 55 are interposed between the solenoid valves 52 and 53 and the source of power. The microswitch 54 is so arranged that when the scale beam is tripped, the operating circuit is opened, closing the pinch valve 16 and releasing the bag clamp 18, thus terminating the bag filling cycle. The microswitch 54 may be a normally closed switch which is positioned for engagement by the beam 56 of the scale mechanism 15 as it moves into its tripped position. However, it will be understood that the arrangement may be reversed with a biased open microswitch located beneath the beam 56.
The starting relay 55 includes a manual start button 57 connected across the contacts of a holding relay 58 so that the operating circuit may be maintained during the filling cycle. The bag actuated microswitch 32 is connected in parallel with the start button 57 so that the cycle may be initiated by the placing of the bag upon the spout. If preferred, the manual start button 57 may be eliminated. Thus, the microswitch 32 is the start switch of the operating circuit 50-51.
A modified arrangement is shown in FIGS. 8 and 9 in which the stop 40, instead of being fixed, is in the form of a retractable stop 40, this constituting the upper end of the spring bracket 44. FIGS. 8 and 9 also illustrate the cooperation between the bag edge 46 and the shoes 35, together with the relationship of these parts to the positions of the rock arm assembly 30 and the striker arm 42.
When the opening or valve of the bag 17 is placed over the spout 13 and slid rearwardly, the edge 46 will slide under the shoes 35, but there will be frictional engagement between the edge 46 and the shoes which causes the shoes to be displaced rearwardly, thus rocking the rock arm assembly 30 in the counterclockwise direction. However, operation of the bag clamp 18 will cause the striker arm 42 to engage the edges of the arms 34, thus rocking the rock arm assembly 30 in the clockwise direction. Due to the'fact that there is a clearance 38 between the shoes 35 and the spout portion 36, the bag edge 46 being located in this clearance, there is nothing to prevent the shoes 35 from sliding over the bag as they move forwardly from the FIG. 8 position into the FIG. 9 position.
The gripping pads 27' may be adjustably mounted on the yoke 26, as shown in FIG. 10, so that a precise relation may be maintained between the striker arms 42 and the arms 34, thus assuring that the bag 17 is firmly gripped while at the same time the rock arm assembly 30 is displaced into its normal switch unoperated position in which it rests against crosspiece 45. The weight distribution of the rock arm assembly 30 with respect to the pivot pin 31 is such that it is gravity biased into this normal position, although a spring may be employed if desired.
The adjustable pad mounting, as shown in FIG. 10, includes a threaded shank 47 for each pad 27 which takes into a threaded opening in the yoke 26', and a jam nut 48 may be provided to lock the pads 27' in their adjusted position. This arrangement also permits the bag actuated start switch mechanism and the bag clamp 18 to be prefabricated as a standard unit and installed on various types of bag filling machines, even though the diameter of the spout 13 may vary from one machine to the other, since the angular relationship of the parts, as shown in FIGS. 8 and 9, and the location of the various centers, need not be varied if the pads 27 are adjustably mounted.
To summarize the operation which has been described in detail in connection with the description of the various parts and subassemblies, as soon as the bag 17 is placed on the spout 13, the rock arm assembly 30 will be rocked into the FIG. 8 position, in which the plunger 33 engages either the fixed stop 40, or the retractable stop 40, and is depressed. This establishes the operating circuit 50-51, thus energizing the holding relay 58, operating the solenoid valve 52 to supply air to the bag clamp 18, and operating the solenoid valve 53 to open the pinch valve 16 or otherwise to energize the feeding mechanism.
Operation of the bag clamp 18 rocks the striker arm 42 into the FIG. 9 position, thus restoring the rock arm assembly 30 to its normal position, and opening the start circuit through the microswitch 32, the operating circuit being maintained at this time and subsequently by the holding relay 58.
When the desired amount of material has been fed into the bag 17, the beam 56 trips, thus opening the microswitch 54 to terminate the filling cycle and to release the bag clamp 18. At this time the bag 17 may be removed from the spout 13, and any incidental movement of the spout, which at this time is in balance and which movement consequently would again close the microswitch 54, will not result in a closing of the operating circuit for the reason that the rock arm assembly 30 is in its normal, switch open position, and the holding relay 58 is deenergized. The operation in this respect is the same irrespective of whether the stop 40 is fixed, as shown in FIG. 2, or retractable, as shown in FIGS. 8 and 9.
Although only preferred embodiments of the present invention have been described herein, it will be understood that various modifications and changes may be made in the constructions shown without departing from the scope of the invention as pointed out in the appended claims.
1. A bag filling machine comprising a chamber, a bag filling spout communicating with said chamber and adapted to project into a bag to be filled, feeding means for causing material in said chamber to flow through said spout and into said bag, bag weight responsive means for rendering said feeding means inoperative when a predetermined amount of material has been fed into said bag, a bag clamp cooperating with said spout for clamping a bag in position on said spout, an operating circuit for controlling the operation of said feeding means and said bag clamp, said operating circuit including a starting relay for closing said circuit and a switch operated by said bag weight responsive means for opening said circuit, said starting relay including a start switch, switch closing means operable by the placing of a bag on said spout for closing said start switch and for causing operation of said bag clamp and said feeding means, and means for opening said start switch immediately after closing same.
2. A bag filling machine as claimed in claim 1 in which said switch closing means comprises a rock arm assembly located above said spout and having shoes spaced from the surface of said spout, a bracket for supporting said bag clamp, and pivot means connecting said rock arm assembly to said bracket whereby displacement of said shoes by the movement of a bag as it is being placed on said spout will operate said start switch.
3. A bag filling machine as claimed in claim 2 which includes a stop member located adjacent the upper end of said rock arm assembly, said start switch being mounted on the upper end of said rock arm assembly and including a plunger located adjacent said stop member whereby rocking movement of said rock arm assembly will operate said switch.
4. A bag filling machine as claimed in claim 2 in which said start switch is mounted on said bracket adjacent the upper end of said rock arm assembly, said start switch having a plunger extending toward said rock arm assembly, and said rock arm assembly including a member located adjacent said plunger whereby the same is depressed by rocking movement of said rock arm assembly.
5. A bag filling machine as claimed in claim 1 which includes a bracket for supporting said bag clamp and in which said switch closing means includes a rock arm assembly pivotally mounted on said bracket and movable between a normal position and a switch operated position, said bag clamp including a clamp arm pivotally mounted on said bracket, and said means for opening said start switch including a striker arm connected to said clamp arm and movable therewith and engaging said rock arm assembly for restoring same to said normal position when said bag clamp is operated.
6. A bag filling machine is claimed in claim 5 in which said clamp arm is mounted above said spout and includes a yoke overlying said spout, a pair of gripping pads carried by said yoke, and adjustable means for mounting said gripping pads on said yoke whereby the movement of said clamp arm can be regulated to correspond with the desired throw of said striker arm.
7. A bag filling machine comprising a supply chamber, a spout communicating with said supply chamber and adapted to project into a bag to be filled, feeding means for causing material in said chamber to flow through said spout and into said bag, bag weight responsive means for rendering said feeding means inoperative when a predetermined amount of material has been fed into said bag, an operating circuit for controlling the operation of said feeding means, said operating circuit including a starting relay for closing said circuit and a switch operated by said bag weight responsive means for opening said circuit, said starting relay including a start switch, and switch closing means operable by the placing of a bag on said spout for closing said start switch and for causing operation of said feeding means, said switch closing means comprising a pair of shoes disposed on opposite sides of said spout and movable between a switch open position and a switch closed position, means mounting said shoes for rearward displacement into switch closed position, said shoes each being spaced from the surface of said spout by a distance sutficient to accommodate the thickness of a bag wall between the shoe and the spout but sufficiently close thereto as to be engaged by said bag incident to the placing of said bag on said spout and displaced rearwardly to actuate said start switch, and means for restoring said shoes to said switch open position immediately after rearward displacement of same, the spaced relationship between said spout and said shoes permitting forward sliding movement of said shoes over said bag incident to said restoring of said shoes to said switch open position.
References Cited by the Examiner UNITED STATES PATENTS 2,052,996 9/1936 Witte 141-361 X 2,697,543 12/1954 Sawyer et al 141-166 X 2,770,439 11/1956 Stafford et al. 141-315 X 3,073,401 1/ 1963- Zenke.
LAVERNE D. GEIGER, Primary Examiner. E. EARLS, Assistant Examiner.