Valve bag feeding method and machine for powder material packaging apparatus

To place the bags on a filling spout, the bags are hurled one at a time w the valve flange through a shaping tube, which is distanced from the spout as to allow the filled bag to be removed from the spout without displacing the tube. The bag is hurled at high speed by at least one continuously moving belt engaging the bag body along the entire length of the tube, as to be placed on the spout substantially when the valve flange leaves the tube. This latter is formed of two symmetric parts, the distance between which is adjustable by means of double screws having two ends threaded in opposite directions and engaging corresponding holes of the two parts of the tube.

BACKGROUND OF THE INVENTION 
This invention relates to the apparatus for automatic packaging of powder 
material, as cement, flour, grain, fertilizer, insecticide, and the like. 
More particularly, the invention relates to a valve bag feeding method and 
machine for such packaging apparatus, wherein the bags are picked up one 
at a time from a magazine to be placed on a filling spout of a packaging 
apparatus. 
Normally said materials are packaged in bags of paper or other material, 
which are provided on a pair of end edges with two flanges as bellows, 
wich are folded on one face of the bag. One of the flanges is provided 
with a valve, which closes automatically due to the pressure of the 
packaged material. 
In a known bag feeding machine of the above type, the bag to be fed is 
picked up by grippers engaging the valve flange. The grippers rock the 
picked bag and carry it toward the spout upon causing the flange to cross 
a funnel for opening the valve. This machine has a disadvantage in that, 
the grippers are carried by a shaft which must rotate and translate 
through reciprocating movements, which require long dead times and produce 
a rather low speed movement of the bag. Furthermore, the funnel is located 
close to the spout, whereby after having guided the bag, the funnel must 
be removed to allow the bag to be filled. 
The main object of the invention is to provide a bag feeding machine, which 
assures the introduction of the bag on the spout, without interfering with 
the filling operation. 
SUMMARY OF THE INVENTION 
According to this object, the bag feeding machine according to the 
invention comprises a shaping tube having a variable section and a 
substantially horizontal axis, said tube being adapted to be crossed by 
the valve flange of the bag and being provided with an axial notch 
directed downwards for the passage of the bag body, and is characterized 
in that said tube is distanced from said spout as to allow the bag to be 
filled and removed from the spout without displacing the tube, means being 
provided for hurling the bag at high speed so as to cause the valve flange 
to cross the tube for opening the valve and to assure its placing on the 
spout substantially when said valve flange leaves the tube.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to FIG. 1, the numeral 11 generically indicates a rotatable 
structure of an apparatus for packaging powder materials, particularly 
cement. The structure 11 is provided with a plurality of spouts 12, 
adapted to connected one at a time with a cement supplying station, 
generically indicated by the numeral 13. To this end, the structure 11 is 
rocked step by step around a vertical shaft 10 to bring the spouts 12 
sequentially on the station 13. Each spout 12 (FIG. 3) terminates with an 
opening directed downwards for the exit of the cement. 
The cement is automatically packaged from the spout 12 into a bag 14, 
indicated by broken lines in FIG. 3. The bags 14 are provided on two end 
edges with two flanges 16 and 17 as bellows, normally folded on one face 
of the bag 14. The lower flange 16 is closed, while the upper flange 17 is 
provided with a valve 18, which must be opened to place the bag 14 on the 
spout 12. Since the cement is sent to the spout 12 under pressure produced 
by compressed air, when the bag 14 is removed from the spout 12, the 
pressure of the cement automatically closes the valve 18. 
The spouts 12 are mounted on the structure 11 so as to be rocked downwards 
after having filled a bag 14, to allow the filled bag 14 to be 
automatically taken off from the spout 12. The structure 11 is surrounded 
by a shell 19 (FIG. 1) having an aperture 20 on the station 13 to allow 
the bags 14 to be placed on the spout 12. 
The bags 14 are feed to the packaging apparatus by a bag feeding machine, 
generically indicated by the numeral 21, which includes a magazine 22 
containing a pile of bags 14, a bag picking and transfering device 23 and 
a bag introducing device 24 providing also for opening the valve 18. 
BAG PICKING AND TRANSFERRING DEVICE 
The bag feeding maching 21 comprises a stationary frame formed of a pair of 
parallel flanks 25 connected by a plurality of transverse bars 26 (FIG. 
2). The mazagine 22 is secured to the flanks 25 by means of a pair of 
plates 27 and is formed by a metallic parallelepiped frame 28, including a 
bottom plate 29 supporting the bags 14. The plate 29 is slightly arcuate 
to take into account the thickners of the folded flanges 16 and is 
slightly inclined rightwards in FIG. 2. The bags 14 are loaded into the 
magazine 22 with the flanges 16 and 17 directed downwards and the flange 
17 having the valve 18 at left. The plate 29 is provided with an aperture 
31 and a portion 32 bent with respect to the plate 29 to cause the flange 
16 of the bottom bag 14 to rock, as indicated in FIG. 2. 
The device 23 comprises a pair of chains 33, each one engaging three 
toothed pulleys 34, 35 and 36. The corresponding pulleys of the two chains 
are secured to three shaft 37, 38 and 39 (FIG. 3) rotatable on the flanks 
25 of the machine. The shaft 39 is connected through a clutch 41 to an 
electric motor 42 adapted to rotate the chains 33 (FIG. 2) clockwise. 
Two grippers 43 for picking up the bags 14 are mounted equidistant on the 
two chains 33, whereby at each cycle of the chains 33 two bags 14 can be 
picked up from the magazine 22. Each gripper 43 is fulcrumed on a pivot 47 
carried by a member 18 secured to a link of the two chains 33. Each 
gripper 43 is held closed by spring means not shown. It is also provided 
with a roller 59 adapted to cooperate with the profile of two stationary 
plates 60 and 62 (FIG. 3) located between the two chains 33 and adapted to 
rock the gripper 43 on the pivot 47 (FIG. 2) against the urge of another 
spring not shown. Another roller 68 of each gripper 43 is adapted to 
cooperate with the profile of two other stationary cam plates 69 and 70 
for opening the gripper 43 against the spring urge. 
Located in correspondence with the two ends of the aperture 31 are two 
wedges 74 (FIGS. 1 and 2). Each wedge 74 is secured to a fluid actuated 
piston 75 operable in cylinder 76 in turn secured to a flange of a 
O-shaped bar 77 of the magazine 22. The piston 75 and a pair of pins 78 
also secured to the wedge 74 can slide in corresponding holes of the other 
flange of the bar 77. The cylinder 76 is adapted to be operated in 
synchronism with the movement of each gripper 43, in a known manner. 
Each gripper 43 is associated with a group of three bars 83 (FIG. 2), each 
one secured to two corresponding links of the two chains 33. Each gripper 
43 is also associated with a wedge 84 secured to other two links of the 
chains 33. The wedge 84 is directed in a direction opposite to the 
movement of the chains 33. When the wedge 84 and the associated gripper 43 
lie in a rectilinear portion of the chains 33, the sharp edge of the wedge 
84 is distanced from the end of the associated gripper 43 less than the 
distance between the flanges 16 and 17 of the bag 14. The gripper 43, the 
bars 83 and the wedge 84 are so distanced from the chains 33 that when the 
bag 14 is partly in the horizontal zone of the chain path and partly in 
the vertical zone, the flange 17 engages the wedge 84 and is rocked 
thereby with respect to the bag 14. 
Three pressure rollers 90 of elastic material, for example rubber are 
mounted on vertical slots of the flanks 25 of the machine frame. Each 
roller 90 is normally held downwards by springs not shown. Two bent 
members 92 (FIG. 1 and 3) are fulcrumed on two pivots 94 secured to the 
flanks 25 adjacent the two pulleys 35 of the two chains 33. Secured to 
each member 92 is an arm 96 (FIG. 1) normally urged by a spring 97 (FIG. 
3) to contact a stationary stop member 98. The arm 96 is adapted to be 
engaged by a chain portion 99 (FIG. 1) laterally connected to each chain 
33. A stationary bar 100 parallel to the pivots 94 is located in 
correspondence with the members 92 to form a guide for the flange 17 of 
the bags 14. 
Upon switching on the motor 42 (FIG. 3), this latter rotates the pulleys 
36, thus continuously moving the two chains 33 (FIG. 3) clockwise, 
together with the grippers 43. Taking into consideration the lower gripper 
43, when it arrives at a predetermined position a bag picking up cycle is 
started. Firstly the two cylinders 76 (FIG. 1) are operated to move the 
pistons 75 rightwards together with the two wedges 74. These latter engage 
the flange 16 (FIG. 2) of the lower bag 14, which is thus further rocked. 
Simultaneously, the roller 68 of the gripper 43 engages the cam plate 69, 
which causes the opening of the gripper 43. When the wedges 74 reach the 
end of their rightward stroke, the roller 68 leaves the plate 69, whereby 
the gripper 43 is suddenly closed and engages the flange 16 of the bag 14. 
Now the cylinders 76 are operated in opposite direction, whereby the 
wedges 74 are restored leftwards. 
Thereafter, the roller 59 of the gripper 43 engages the cam portion 67 of 
the plate 62, which rocks the gripper 43 clockwise on the pivot 47, thus 
extracting the flange 16 of the bag 14 from the magazine 22 and assuming 
the horizontal position of the upper gripper 43 in FIG. 2. Now the 
transport of the extracted bag 14 is effected, while the bars 83 and the 
wedge 84 prevent the bag 14 from contacting the chains 33. In turn the 
rollers 90 prevent the bag 14 from flutering. Before the gripper 43 
reaches the vertical portion of its path, the two lateral chain portions 
99 (FIG. 1) engage the arms 96, thus rocking the members 92 as to bring 
them out of the path of the bags 14. Thereafter, the roller 59 (FIG. 2) of 
the gripper 43 engages the cam plate 62, whereby the gripper 43 is rocked 
to the vertical position and inserts the bag 14 between the bar 100 and 
the members 92 (FIG. 1). Since the radius of the path of the bag 14 is 
greater than that of the chains 33 (FIG. 2), the bag 14 brings now its 
flange 17 to engage the wedge 84, whereby the flange 17 is rocked with 
respect to the bag 14. 
The lateral chain portions 99 (FIG. 1) release now the arms 96, whereby the 
members 92 are brought to a stop positon for the flange 17. Thereafter, 
the roller 59 (FIG. 2) leaves the plate 62, thus causing the gripper 43 to 
rock counterclockwise on the pivot 47, while the roller 68 engages the cam 
plate 70, which causes the gripper 43 to open. The flange 17 of bag 14 is 
now arrested by the bar 100 and the members 92. Finally, the roller 68 
leaves the cam plate 70, whereby the gripper 43 closes again after having 
disengaged the flange 16. While this gripper 43 leaves the plate 70, the 
other gripper 43 is ready to extract the next following bag 14, whereby 
the transport cycles are effected sequentially. 
BAG INTRODUCING DEVICE 
According to a first embodiment of the invention, the bag introducing 
device 24 is supported by a plate 104 and a C-shaped bar 105, both secured 
to one of the flanks 25 of the machine. Secured to the bar 105 are two 
transverse members 106 (FIG. 3) having a reverse T-shaped section and 
mounting a shaping tube 107 for the flange 17 of the bag 14, which is 
adapted to open the valve 18 of the bag 14. Particularly, the shaping tube 
107 is formed of two parts 108 (FIG. 4) mutually symnmetric in respect to 
a vertical plane. The two parts 108 terminate downwards with two bent 
edges 109 defining an axial notch 111 for the passage of the body of the 
bag 14. Secured to each transverse member 106 (FIG. 3) is a bracket 110, 
on which the two parts 108 can be individually secured at an adjustable 
mutual distance between certain limits, in order to adequate the tube 107 
to the width of the flange 17 of the bag 14. In fact the width of the 
flange 17 may vary between certain limits according to the sizes of the 
bags 14, which follow specific standards and may also vary according to 
the material to be filled in. 
The shaping tube 107 is distanced from the spout 12 as to allow the bag 14 
inserted on the spout 12 to be filled and removed from the spout 12 
without displacing the tube 107. Since, as it has been mentioned 
hereinabove, the spout 12 is rocked downwards when the bag 14 is full, to 
allow the removel of the filled bag the distance between the left end of 
the tube 107 and the structure 11 must be at least slightly greater than 
the width of the bag 14. This latter requires to be hurled from the tube 
107 to the spout 12 for being inserted therein. 
For moving the flange 17 of the bag 14 through the shaping tube 107, the 
bag 14 is hurled at high speed by continuously moving means engaging the 
bag 14 below the notch 111 of the tube 107. Said moving means include a 
driving belt 112 (FIG. 1) wound on a driving pulley 113 and a set of idle 
pulleys 114 and 115. The pulley 113 is secured to a shaft 116 of an 
electric motor 117 (FIG. 2) secured to the plate 104. The pulleys 114 are 
rotatable on corresponding shafts 118 secured to the plate 104, whereas 
the pulleys 115 are rotatable on corresponding shafts 119 (FIG. 4) each 
one secured to a fork 120. This latter is provided with a prismatic 
projection 121, which is slidable into a horizontal guide 122 provided on 
a support member 123 secured to the plate 104. A compression spring 124 
urges the fork 120 rightwards in FIG. 4, to tension the belt 112 and to 
urge same toward the bag 14. 
The path of the belt 112 (FIG. 1) includes a rectilinear portion comprised 
between one of the pulleys 114 and one of the pulleys 115 and having a 
length substantially equal to the length of the shaping tube 107. This 
rectilinear portion is vertically aligned with the notch 111 (FIG. 4) of 
the tube 107 and cooperates with a driven belt 126 (FIG. 1) wounded on a 
set of idle pulleys 128 rotatable on vertical shafts 127. These latter are 
mounted on a plate 129 having a pair of lugs 125 secured to the transverse 
members 106 by means of a pair of vertical bars 130. The two end pulleys 
128 (FIG. 1) are mounted on the plate 129 by means of forks similar to the 
forks 120 (FIG. 4) above described for the pulleys 115, in order to 
tension the belt 126. 
The shaping tube 107 is provided with a cross section variable along its 
axis, which is defined by the series of baricenters of the various cross 
sections. This axis is indicated by dot and dashes in FIG. 3 and by the 
numeral reference 131. Particularly, the shaping tube 107 includes a first 
portion 132 substantially in form of a funnel and having a cross section 
oblong in the horizontal direction. This portion starts with a section 133 
(FIG. 4) of substantially rectangular shape, with rounded angles and with 
a width much greater than the width of the flange 17 of the bag 14. The 
portion 132 terminates with a section 131 having the upper edge slightly 
rounded and a width slightly narrower than the width of the flange 17. 
Therefore under the urge of the belts 112 and 126 on the bag 14, the 
flange reaching the section 134 is compelled to be slightly curved, 
whereby the two wings of the flange 17 are bent downwards. 
The portion 133 of the shaping tube 107 is followed by a portion 136 (FIG. 
3) having a constant cross section and followed in turn by another portion 
137 having again a variable section. The portion 137 starts with the 
section 134 (FIG. 4) and terminates with a section 138 substantially 
oblong in the vertical direction. However, the perimetric length of the 
cross section of the portion 137 remains substantially constant from the 
section 134 to the section 138. 
The shaping tube 107 is crossed through its entire length by the bar 100 
and by a second bar 139 (FIG. 1) parallel to the bar 100 and aligned to 
the corner of the members 92 in the position stopping the flange 17. 
Secured to the member 92, adjacent the tube 107, is a pin 140, which is 
provided to reduce to a minimum the discontinuity of the guide of the 
flange 17 from the members 92 to the bar 139. 
The zone of the tube 107 adjacent the notch 111, and particularly, the 
rectilinear corner 141 formed by each bent edge 109 on the corresponding 
part 108 of the tube 107, is located at a constant distance from the 
corresponding bar 100, and 139 respectively. Therefore, the axis 131 (FIG. 
3) of the portion 137 of the tube 107 is slightly inclined upwards with 
respect to the bars 100 and 139. When the flange 17 of the bag 14 is 
hurled to cross the portion 137 of the tube 107, the wings of the flange 
17 bent downwards in the portion 136 (FIG. 4) are compelled to raise. 
Since the bag 14 is gripped between the belts 112 and 126, the same wings 
are urged to remain in contact with the bars 100 and 139, whereby the 
valve 18 is automatically opened with a high reliability, as indicated in 
FIG. 4 by the dot and dash lines adjacent the section 138. 
The bag introducing device 24 (FIG. 1) comprises also a continuously 
rotating roller 143, which is adapted to cooperate with the bar 100 for 
advancing the bag 14, arrested by the bar 100 and the member 92, toward 
the shaping tube 107. The roller 143 is secured to a shaft 144 of an 
electric motor 146. This latter is secured to one end of an oscillating 
arm 147 (FIG. 3) fulcrumed on a stationary shaft 148 and connected by 
means of a rod 149 to a fluid actuated piston 151 operable in cylinder 152 
secured to one flank 25 of the machine frame. The cylinder 152 can be 
actuated as to move the piston 151 either in one direction for rocking the 
arm 147 counterclockwise, or in the opposite direction for restoring the 
arm 147 clockwise. 
After a predetermined delay with respect to the operation of the cylinders 
76 (FIG. 1), the cylinder 152 is actuated as to move the piston 151 (FIG. 
3) rightwards. The arm 147 is thus rocked counterclockwise and brings the 
rotating roller 143 to engage the flange 17 of the bag 14 contacting the 
bar 100. The roller 143 under the action of the motor 146 (FIG. 1) moves 
the bag 14, guided by the bars 100 and 139, toward the belts 112 and 126. 
The belt 112 moved by the motor 117 (FIG. 3) and cooperating with the belt 
126 hurls now the bag 14 at high speed leftwards, thus compelling the 
flange 17 to cross the shaping tube 107. This latter causes the valve 18 
to be opened, while the bag 14 is urged by the belts 112 and 126 to leave 
the tube 107, till the flange 17 is inserted on the spout 112 of the 
packaging apparatus, as indicated in FIG. 3. Thereafter, the cylinder 152 
is actuated so as to restore the arm 147 to the position of FIG. 3, 
whereby the bag introducing device 24 completes its cycle. 
According to another embodiment of the invention, the bag introducing 
device 24 includes a stationary frame 160 (FIG. 5) mounting a pair of bar 
161 located at the entrance of the shaping tube 107 for guiding and 
supporting the bag 14. The shaping tube 107 is mounted on a pair of 
L-shaped supports 164 and 166 secured to the frame 160. 
The distance between the two symmetric parts 108 (FIG. 9) of the tube 107 
can be easily adjusted to adequate it to the width of the flange 17. To 
this end each part 108, near its two ends, is provided with two shoulders 
167 and 168 (FIG. 5) each one provided with a vertical threaded hole 169 
(FIG. 7). A screw 170 is screwed in the hole 169 of each shoulder 167 and 
168 and crosses a corresponding oblong slot 171 (FIG. 6) of the 
corresponding support 164, 166. 
Each screw 170 is secured upwards to a manipulative lever 172 bodily 
rotatable with a washer 173 (FIGS. 7 and 9). A gasket 174 is located 
between each support 164, 166 and each washer 173. Another gasket 176 is 
located between the support 164, 166 and the relevant shoulder 167, 168. 
Upon rocking each lever 172 in one direction, the relevant shoulder 167, 
168 is immediately and rigidly locked on the corresponding support 164, 
166. By rocking the lever 172 in the opposite direction, the shoulder 167, 
168 is unlocked on the support 164, 166. 
Each shoulder of each pair 167, 168 (FIGS. 8 and 9) is also provided with a 
horizontal threaded hole 177, and 178 respectively. The two holes of each 
pair 177 and 178 are threaded in opposite directions and are engaged by a 
double screw 179 having two portions threaded also in opposite directions. 
Each screw 179 is rotatable into a cylindrical hole of a rib 181 of the 
corresponding support 164, 166 and is secured to a corresponding 
manipulative knob 182. 
Assuming that the two parts 108 are correctly secured at a predetermined 
distance, to alter the distance between the two parts 108 (FIG. 6) of the 
tube 107, the four levers 172 are rocked as to unlock them from the 
supports 164 and 166. Then the two knobs 182 (FIGS. 8 and 9) are rotated 
in the same direction and simultaneously. The two screws 179 thus cause 
the pair of shoulders 167 and 168 to move in opposite directions either 
for increasing or for decreasing their distance, whereby the distance 
between the two parts 108 is altered, while these letter remain always 
equally distanced with respect to their plane of symmetry. Therefore, this 
plane of symmetry, and consequently also the axis 131 (FIG. 5) of the tube 
107, remains always centered with repect to the spout 12 (FIG. 1). Of 
course, in the case the two parts 108 are initially incorrectly secured on 
the supports 164 and 166 (FIG. 6), for instance because they are 
converging or diverging, the two knobs 182 must be rotated individually. 
In any case after having adjusted the distance between the parts 108, they 
are again locked on the supports 164, 166 by accordingly rocking the 
levers 172. 
Secured to the machine frame 160 is a bracket 184 (FIG. 6) including an 
upper plate 187 adjustably mounted on a pair of supports 188 and 189 of 
the machine frame 160, and a lower plate 190 (FIG. 9) secured to the upper 
plate 187 by means of a set of transverse plates 191. The bracket 184 
carries continuously moving means, generically indicated by 186 (FIG. 6), 
for hurling the bag 14 toward the spout 12. The moving means 186 comprise 
a set of pivots 192 (FIG. 6) secured to the plates 187 and 190. Each pivot 
192 rotatably mounts, by means of a rolling bearing, a corresponding 
toothed pulley 193 (FIG. 9) cooperating with a driving toothed belt 194. 
The plate 187 is provided with a notch 196 (FIGS. 8 and 9) for adjustably 
mounting a plate 197, by means of a pair of screws 199 screwed on a pair 
of brackets 198. The external screw 199 engages also a ring 200 integral 
with another screw engaging a transverse bracket 210, whereby by screwing 
on this latter screw the corresponding bolt, the position of the plate 197 
can be adjusted. 
Secured to the plate 197 is the stator of an electric motor 201 having a 
shaft 202 secured to the hub of a toothed driving pulley 203 also engaged 
by the belt 194. By adjusting the position of the plate 197 on the notch 
196, the tension of the driving belt 194 can be accordingly adjusted. The 
adjustable mounting of the plate 187 on the supports 188 and 189, allows 
the adjusting of the position of the belt 194 with respect to the symmetry 
plane of the shaping tube 107, according to the thickness of the bag 14. 
The machine is also provided with a second bracket 184' (FIG. 6), 
substantially symmetric to the bracket 184, whereby the corresponding 
parts of the bracket 184' are indicated with the primed numeral references 
of the parts of bracket 184. Therefore, the bracket 184' carries a second 
set of toothed pulleys 193', a second electric motor 201', the shaft 202' 
of which (FIG. 7) is secured to a driving pulley 203', and a belt 194' 
engaging the pulleys 193' and 203', whereby the path of the belt 194' is 
symmetric to that of the belt 194. It is thus evident that both belts 194 
and 194' drive the bag 14 into the shaping tube 107. 
Contrary to the bracket 184, the plate 187' of the bracket 184' is provided 
with a bushing 204 (FIG. 9) rotatably mounted on a pivot 206 secured to a 
support 207 (FIG. 6) integral with the machine frame 106. Particularly, 
the pivot 206 comprises a threaded portion screwed into a hole of the 
support 207 and a head 208 (FIG. 9) for retaining the plate 187'. 
Furthermore, the plate 187' is provided with at least a slot 209 (FIG. 8) 
adapted to slide on a corresponding pin 211 provided with a head, which is 
directed downwards and is secured on a shoulder 211 (FIG. 9) provided on 
the frame 160. 
Finally, adjustably secured to the plate 187' is a plate 214 integral with 
a L-shaped member 215 (FIG. 8). This latter is provided with a hole 216 
adapted to engage an indexing pin 217 (FIG. 9) secured to another shoulder 
218 of the frame 160. The member 215 carries a pair of stop screws 219 
located one upwards and the other downwards with respect to the hole 216. 
The screws 219 are adapted to stop against the shoulder 218. The screws 
219 allow the adjustment of the position of the belt 194' with respect to 
the plane of symmetry of the shaping tube 107. 
A support 221 (FIG. 8) secured to the frame 160 mounts a toggle locking 
device known per se, which comprises a manually operable lever 222, a 
locking lever 223 and a rod 224 connecting the levers 222 and 223. In the 
position of FIG. 8, the rod 224 is behind the dead point and, through a 
lug 225, holds the lever 223 locked against the member 215, whereby it is 
impossible to unlock the bracket 184' without manually operating the lever 
222. 
Finally, secured to each of the two plates 187 and 187' are two blocks 226, 
to which two stems 228 are secured. The stems 228 extend through two 
corresponding large holes 229 (FIG. 9) provided on the corresponding part 
108 of the tube 107. The two stems 228 are also secured to a substantially 
horizontal corresponding bar 231 for supporting the flange 17 of the bag 
14. The bars 231 comprise each one an arquate portion 232 (FIG. 8) and are 
adapted to facilitate the opening of the valve 18, in a manner similar to 
the one described for the bars 100 and 139 of FIGS. 1-4. 
In the case it is necessary to enter the space between the belts 194, 194' 
(FIG. 8), for example for replacing one of the belts, the lever 222 is 
manually rocked clockwise, thus removing the lever 223 from the member 
215. Thereafter the bracket 184' is manually rocked around the pivot 206 
(FIG. 6) between the limits allowed by the slot 209 (FIG. 8). Even if the 
part 108 of the tube 107 corresponding to the bracket 184' remains 
stationary, the holes 229 (FIG. 9) are enough large to allow the 
displacement of the stems 228 together with the bracket 184'. 
The operator can now enter the space between the pulleys 193, 203 and 193', 
203' and remove downwards the belt 194 or 194' to be replaced. After 
having replaced the belt, the bracket 184' is returned to engage the hole 
216 on the indexing pin 217 and is locked in this position by returning 
the lever 222 to the position of FIG. 8. Obviously, the displacement of 
the bracket 184' may be used for other operations of maintenance or for 
unlocking accidental situations, for example for removing a bag 14 
incorrectly entangled into the tube 107. 
It should be evident that many modifications, improvements and additions of 
parts may be made to the described bag feeding machine, without departing 
from the scope of the invention. For example, the described feeding 
machine 21 may be used for a packaging apparatus having one or more spouts 
in fixed positions. If only one spout 12 is provided, the feeding machine 
21 will be located in a fixed position, with the shaping tube 107 aligned 
with the spout 12. On the contrary, if the packaging apparatus is provided 
with more than one spouts 12, the feeding machine 21 may be mounted on a 
carriage, which can be moved according to a predetermined program or cycle 
to bring sequentially the shaping tube 107 in front of the various spouts.