US3527180A - Devices for transporting and feeding sacks and similar nonrigid containers into sewing machines for their sealing - Google Patents

Description

United States Patent [56] References Cited I UNITED STATES PATENTS [72] Inventor Renzo Giuseppe Cerioni Corso Venezia 10, Milan, Italy [21] Appl. No. 766,576

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Primary ExaminerAlfred R. Guest Atromey-Waters, Roditi, Schwartz and Nissen [54] DEVICES FOR TRANSPORTING AND FEEDING SACKS AND SIMILAR NON-RIGID CONTAINERS ABSTRACT: A device for feeding sacks and non-rigid con- :g g X S biiAiulNEs FOR THEIR SEAUNG tainers to sewing machines for the sealing of their mouths, en-

suring a suitable stretching and flattening of the mouths for [52] 0.5. the sealing. The device comprises two sets of conveyors in sequence, with swingable mounting of the initial conveyor a [51] Int.C1................ [50] FieldofSearch...........................................

spring biased to closed position, and a power drive to override the bias under control of sensing devices for the sack mouth.

DEVICES FOR TRANSPORTING AND FEEDING SACKS AND SIMILAR NONRIGID CONTAINERS INTO SEWING MACHINES FOR THEIR SEALING vantageously applied to the apparatus described in US. Pat. 1

application Ser. No. 760,878, September 19, 1969, to which reference is made for better understanding of the purposes of the present invention.

An object of the present invention is also the devices produced and operated in applying the said improvement, and whose characteristics will be specified below.

It is known that particularly in the case of sacks of large dimensions and/or of cloth or other material which is very non-rigid, those conditions of perfect stretching and flattening ofthe relative mouth which are desirable are not conserved or not completely conserved during the transfer of the said mouth by manual means or by grasping and stretching apparatus into the mechanical transporter of the sewing machine, this mechanical transporter being generally composed of a pair of opposing belts or tracks counter-rotating and presenting two parallel branches very close to each other and travelling in the same direction and with the same speed of transport as the sacks, under the action of the means driving the machine.

It can sometimes happen, and in fact happens often when working with sacks made of very non-rigid material, that during the said transfer phase, and in any case before completion of the fitting ofthe said mouth into the transporter, the mouth of the sack becomes partially slack. It is evident that if the mouth of the sack does not arrive at the sewing machine and traverse it in a perfectly stretched and straight condition. then the sealing cannot be effected to the degree of completeness and regularity desired, which obviously prejudices the state and protection of the products contained in the sack itself, which might be for example powdery or granular.

Even a small degree of slack or flabbiness prejudices in particular the sealing in those cases where it is carried out by first folding over the edge of the mouth. In these cases a regular fold is not attained and neither is the desired parallel condition offold and stitching.

Further drawbacks originating from even a slight fiabbiness in the mouth of the sacks, and which are detrimental to their closing by sewing, can be easily envisioned by experts in the field.

This having been said, the object of this invention is the provision ofimproved devices which eliminate the above mentioned and other drawbacks which present themselves during operation of apparatus ofthe type and for the uses considered.

In particular. the object of this invention is the provision of improved devices which include those means and operating under those conditions which ensure that the engagement of the mouth of the sack over the whole of its length and the transporting of the mouth into the sewing machine is effected before the operator abandons the sack, or before the withdrawal from the said mouth of the rods of the apparatus used for gripping and stretching.

In substance, the improved device consists of a transporting system which includes at least two pairs of counter-rotating belts or tracks arranged in succession along the path of travel of the mouth of the sack, between the position where the mouth, already in the stretched position, is gripped, and the position where it is fed into the sewing machine, the first pair being composed of belts or tracks which can be alternately spaced somewhat apart or brought close together so that they completely grip the said mouth. This first pair is positioned so The apparatus also includes sensing means for sensing the arrival of the mouth stretched by the rods in the space between the first pair of belts when spaced apart, and driving means which are actuated by the said sensing means and which bring about the reciprical closing together of the branches of the belts or tracks of the said first pair on to the two sides of the said mouth over its whole length, this operation being carried out while it is still gripped and taut, and the said apparatus is released later when the belts or tracks have clamped themselves around the said mouth. Finally the device includes further means which return the belts or tracks of the said first pair to the condition where they are spaced apart, in preparation for the repeat of the cycle of the arrival of another sack which comes about after the mouth of that sack engaged in the device has been totally transferred to between the belts or tracks of the next pair, the branches of which are always close together.

According to a preferred embodiment of the improved device, each belt or track of the two pairs is held taut between two driving pulleys one at each end, the first pulleys of the second pair being coaxial with the second pulleys of the first pair, and the axes of the said coaxial pulleys comprising the axes around which the belts or tracks of the first pair can be I spread by opening angularly large enough to give rise to the space necessary between the adjacent branches for the temporary positioning of the mouth stretched by the rods of the gripping and stretching apparatus. These and other more specific characteristics of the invention and the advantages resulting from them will be better understood during the course of the detailed description which follows of a preferred but not exclusive embodiment of the invention, shown in the accompanying drawing, in which only the essential operative parts of the improved device have been shown, with the omission of mechanisms, complementary and structural devices and means, which in themselves are not characteristics of the invention and can be implemented by the application of currently known techniques. In the said drawings:

FIG. 1 is a perspective view of the device immediately prior to the transfer of the sack from the mouth handling and distention device to the stitching machine conveyor;

FIG. 2 shows the device of FIG. 1 after completion of the first stage of the transfer operation:

FIG. 3 is a plan view, in a simplified and schematic constructional form of a device to perform the transfer operation automatically, as a function of the progressive feed of the sacks: and

FIG. 4 is an elevation view of the device in FIG. 3. In the setup described below, it is assumed that the device is linked to a unit for sealing the sticks, b y stitching them, and comprising an apparatus (for which a detailed description is given in the above mentioned application) having operational characteristics based on vertical and parallel rods (10 and 1]), suitable for insertion, by downward movement B, into mouth 12 of sack 13 being fed in direction A at uniform speed, ag. on a belt or track conveyor. These rods carry out their downward movement sufficiently close together to ensure that they go right into the sack mouth, i.e., with the sack open. Obviously these operations can also be performed manually.

While the sack is being fed normally in direction A, assisted by a corresponding movement on the part of the structure carrying the rods, they undergo spacing movement C so that they engage in two diametrically opposed points in the mouth of the sack 12, widening it and distending it in a plane identical to the direction of feed A. The mouth thus distended is shown at 12', and it has to be fed and inserted in that state between the operating parts of the stitching machine (schematically indicated at 15) by means of the action of the conveyor 12", while the said rods are withdrawn from the mouth and carried back to their initial position, with everything being as described in detail in the above-mentioned application, ready for the next sack being fed in direction A. When this is done manually, the rod movements are replaced by finger operations on the part of the operator. In accordance with the present improvement, the said conveyor comprises at least two pairs of conveyor belts 20 and 21 and 22 and 23, respectively, which encircle the sacks and travel at a linear speed equal to feed speed A to form two conveyor systems which operate in succession.

The bottom conveyor has belts 20 and 21 which pass around bottom return pulleys 24 and 25 and top return pulleys 26 and 27, arranged in such a way that sections 28 and 29, respectively, of the said belts move parallel and close together, and travel in the same direction at identical speeds, so as to ensure the desired transfer of the distended sack mouths under the action of stitching machine 15. The top conveyor system, viz. the one which is the first to receive the flattened mouths, comprises belts 22 and 23 which pass around bottom return pulleys which are coaxial, adjacent and rotatively connected to top pulleys 26 and 27 in the lower system and around top pulleys 30 and 31. These top and bottom pulleys in the top system are pin mounted and the pins, in turn, are mounted on rigid arms 32 and 33 (FIGS. 3 and 4) and can be rotated around axes 34 and 35 (FIG. 1) of top pulleys 26 and 27 in the bottom system and the bottom pulleys in the top system. These two arms 32 and 33, together with their belts 22 and 23 can be symmetrically moved in directions F and G (FIG. 2) and closed in directions F and G (FIG. 1) for rotation around the aforementioned axes 34 and 35 respectively, as can be seen from a close look at FIGS. 1 and 2.

Furthermore, this device is dimensioned in such a way that belts 22 and 23 of the top system form; when the arms are moved, a triangular area with the vertex pointing in the direction of sack feed A and with the hypotenuse much greater than the maximum longitudinal dimension presented by distended mouth 12' of the sacks to be closed. Under the operation of suitable feeler, slave and control devices, the above mentioned parts are controlled in such a way that the transfer from the sack handling and distention device, which comprises rods and 11 to the stitching machine conveyor is carried out in three successive stages which follow each other at minimum time intervals, viz. mouth 12 distended between rods 10 and 11 arrives fully in the area defined by forked belts 22 and 23 (FIG. 1): the arms carrying top return pulleys 30 and 31 rotate towards each other, indirection F and G', grasping mouth 12 between the adjacent sections of belts 22 and 23 (FIG. 2):

and rods 10 and I] withdraw in an upward direction, as shown by E, from the mouth of the sack, when the sack has been engaged between the belts of the top conveyor system and, therefore, there is no longer any possibility of flabbiness or slack occurring in the mouth of the sack.

Obviously all the phase transfer times follow consecutively without sack feed A being interrupted, since rods 10 and 11 follow this movement (as described in the above mentioned patent applications) and belts and 23 of the conveyor rotate continuously at the linear velocity corresponding to that of the said feed A.

Thus, starting from the position in FIG. 2, and with previous withdrawal E of rods 10 and 11, the flattened sack mouths 12 continue their infeed and travel without interruption continuity of from the top conveyor system to the bottom one (in other words between belts 20 and 21) and then into the stitching machine 15. Once the travel of the bottom conveyor system has been completed, arms 32 and 33 of the top conveyor system are again moved in directions F and G, and return to the condition illustrated in FIG. 1, so that the cycle can be repeated for the next sack and so on.

It is obvious that, starting from the moment when rods 10 and 11 have fully distended each mouth 12 in FIG. 1 the said mouths are constantly engaged and locked in their direct distended condition by rods 10 and 11, by belts 22 and 23 and finally by belts 20 and 21 without it being possible for any flabbiness slack to occur or for any alteration to be made to the aforementioned distended and flat conditions of the mouths.

The device described above is automatically controlled. generally in such a way as not to influence its operation by different sack mouth sizes (obviously compatible with the handling and distention possibilities of rods 10 and ll of the apparatus described in the above mentioned application) by devices which follow up the detection action carried out by special sensing devices. In particular, the device can be provided with an initial feeler operating in the transverse plane marked X which indicates that the front edge of distended mouth 12' has arrived close to the bottom of the area between the spread arms of the top conveyor system, or in other words, that the whole mouth is ready to be engaged by the said system, while a second feeler, operating in the transverse plane marked Y will indicate that the bottom edge of the same mouth has entered the intake of the bottom conveyor system, i.e. that the top conveyor system, with opened arms, no longer engages the mouth of the sack in question. The condition signalled by the first feeler determines the closure movement (F' and G) of the arms around the mouth which is still stretched between rods 10 and 11, and the condition detected by the second feeler determines the movement of the said arms, to prepare the system to receive the next sack mouth and so on.

FIGS. 3 and 4 schematically show apparatus for the operation and control of the moving parts in the improved device, or in the top conveyor system. The arms 32 and 33 in the said top system are angularly integral with levers 42 and connected to link rods 44 and 45 which, in turn, are joined at pivot 46 on longitudinally movable part 47 which is stressed in one direction by a spring 48 and its end, opposite pivot 46 has a hook 49 which can be engaged by claw 50. Claw 50 moves up and down on pin 51 and is stressed by spring 52, in the direction in which it is hooked and held by part 47, pulling against spring 48, in the position as indicated in FIG. 3, in which arms 32 and 33 are spread apart. Claw 50 can be disengaged from hook 49, for example, by energizing solenoid 53 (FIG. 3), by closing switch 54.

Part 47 can, furthermore, be carried back to the hooked position in FIG. 3 by means of suitable mechanical means which includes, for example, pinion 55 which meshes with rack 56 which is on part 47 and is operated, for example, through a pair of gears 57 and 58 (FIG. 4) by shaft 59 via electromagnetic clutch 60 which has a switch 61 in its excitation circuit.

The feeler operating in plane (X) has sensing device 54a controlling switch 54, while the feeler in plane (Y) has a similar sensing device 61a to control switch 61. Obviously other means can be employed, e.g. photoelectric cells or resistors for detecting the arrival or the passage of the sack mouths either in or outside certain given positions, and to initiate the necessary operations.

In FIG. 3, when the front end of distended sack mouth 12' trips feeler 54a (shown in its displaced position) the consequent closing of switch 54 energizes solenoid 53 which causes part 47 to unhook and allows spring 48 to close the top conveyor system arms around mouth 12'.

When sensing device 61a is no longer affected by the sack, which has passed beyond plane (Y), switch 61 (FIG. 4) is closed to engage clutch 60 which temporarily with claw 50, and, thus, again causing the arms of the top conveyor system to open. Obviously limit switches or other means are provided to de-energize electromagnetic clutch 60 once the movement is over, and the various circuits are also provided with suitable self-excitation devices to ensure that the operation of electromagnetic clutch 60 through sensing device 61a only takes place once the mouth 12 is in contact with the said sensing device and at the very moment when the said sensing device loses contact with the mouth as it fully moves away.

It is, furthermore, obvious that the various means and technical/constructional solutions, described above, are purely only a number of possibilities, and that they can be amply modified and even replaced by other equivalent ones, without in any way deviating from the scope ofthis invention.

I claim:

1. Apparatus for feeding distended open mouths of sacks to a sewing machine, said apparatus comprising first and second conveyor means positioned sequentially from said sewing machine to feed the sacks thereto, said second conveyor means including swingably mounted elements which can open to receive the sacks and close to engage and feed the sacks to the first conveyor means for subsequent feed to the sewing machine, spring means acting on said second conveyor means to urge the swingably mounted elements to open position, sensing means positioned adjacent said second conveyor means to detect the presence therein of a sack, and power means connected to said sensing means for being operated thereby and coupled to said second conveyor means to close the same against the opposition ofithe spring means when the sensing means detects a sack within the second conveyor means.

2. Apparatus as claimed in claim 1 wherein said first and second conveyor means include respective pairs of belts having straight branches opposed to one another to feed sacks therebetween.

3. Apparatus as claimed in claim 1 wherein said swingably mounted elements in the open position define a triangular space with a vertex facing in the direction of feed of the sacks and having a length in the direction of feed which exceeds the length of the mouth of'the sack.

4. Apparatus as claimed in claim 2 wherein said first and second conveyor means comprise respective upstream and downstream pulleys on which the belts travel, the upstream pulleys of the second conveyor means being coaxial with the downstream pulleys of the first conveyor means, said swingably mounted elements being pivotal about the common axes of said coaxial pulleys.

5. Apparatus as claimed in claim 1 wherein said sensing means comprises a first sensing device in the path of the mouths of the sacks for detecting entry of a sack into the second conveyor means and a second sensing device for detecting exit of a sack from the second conveyor means.

6. Apparatus as claimed in claim 5 wherein said power means comprises a locking device to hold the swingably mounted elements in closed position, said locking device being coupled to said second sensing device for being deactivated when the sack has passed from the second conveyor means to permit the swingably mounted elements to open under the action of the spring means, and a drive means coupled to the first sensing device to close said swingably mounted elements when the sack enters the second conveyor means.

7. Apparatus as claimed in claim 6 wherein said drive means comprises an electromagnetically actuated clutch controlled by said first sensing device.

8. Apparatus as claimed in claim 7 wherein said locking device comprises an electromagnetically operated locking member controlled by said second sensing device.

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