GB2092978A

GB2092978A - Transport device for variable-width parallelepipedal cartons

Info

Publication number: GB2092978A
Application number: GB8116983A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-02-13
Filing date: 1981-06-03
Publication date: 1982-08-25
Also published as: DE3124626A1; FR2499949A1; IT8120778V0; DE3124626C2; FR2499949B1

Abstract

A pair of belt conveyors (6) extend along respective sides of a carton support and advancement plane (3). Means for adjusting the mutual distance of the conveyors comprise a controlled rotatable shaft (29), which extends transversally to the carton advancement path and is provided with two threaded portions (28) with opposite inclination. Said portions are engaged with respective female threads, which carry the conveyors in axial-direction resiliently yieldable manner. The resilient connection between the conveyors and the female threads makes it possible to establish a working pressure of the conveyors on the carton sides. <IMAGE>

Description

SPECIFICATION Transport device for variable-width parallelepipedal cartons The present invention relates to a transport device for variable-width parallelepipedal cartons.

There are known those packing techniques, which provide for the use of parallelepipedal cartons which, when filled with the products destined therefor, are closed and sealed, for example by applying adhesive tapes along the two longitudinal splits which are defined above and beneath the carton when the flaps are folded.

For the closing and sealing operations there are usually employed more or less automatic machines, which have the common feature of including a carton support plane, along which the cartons are advanced to pass through a suitable closing and/or sealing assembly.

For the advancement of the cartons, said machines employ in many cases a pair of belt conveyors, which are caused to engage opposite sides of the cartons.

Of course, an important requirement is that such conveyors can be moved to and from one another, so as to adjust their mutual distance to the variable width of the cartons to be handled.

In the U.S. patent No. 4,161,138 of the same Applicant the problem is solved by mounting one end of the two conveyors on sliders running on transversal guides and by fastening said sliders to opposite sections of an endless chain provided with suitable driving means, while the other end of the conveyors is in turn releasably fixed to an axially yieldable transversal guide. The distance adjustment is carried out by driving suitably the endless chain after having released momentarily the connection between the other end of the conveyors and the respective guide and before the same connection is restored in the new selected position. The yieldingness of the guide then allows the conveyors to apply a certain working pressure to the carton sides, as a consequence of the fact that the conveyors may conveniently be adjusted at a distance slightly smaller than the width of the carton.

The above described solution has the drawback of providing for a rather complicated operation, but particularly that of allowing the distance adjustment, with establishment of the due working pressure, only when the machine is empty, i.e. without any carton inserted between the two conveyors. When a carton is inserted, in fact, it is possible to cause the engagement of the conveyors with the carton sides, but it is necessary to renounce establishing that working pressure, which is necessary forthe transport of the carton and can be obtained, on the other hand, only by approaching the two conveyors to one another more than strictly required by the width of the carton.

Object of the present invention is therefore to realize a transport device of the type with belt conveyors engageable with the carton sides, in which the adjustment of the distance between the conveyors can be carried out with simple operation and with establishment of working pressure with already inserted carton too.According to the invention, such an object is attained by means of a transport device for parallelepipedal cartons, comprising a carton support and advancement plane, a pair of belt conveyors extending along respective sides of said support plane to engage corresponding sides of the cartons for the advancement of the same cartons along said support plane and means for adjusting the mutual distance of said conveyors, characterized in that said adjusting means comprise at least one controlled rotatable shaft, which extends transversally to the carton advancement path and is provided with threaded portions with opposite inclination, which are engaged with respective female threads which bear said conveyors in axial-direction resilientlyyieldable manner.

In the device according to the invention the adjustment of distance of the two belt conveyors is thus produced by a simple rotation of a transversal shaft, whose threaded portions at opposite inclination cause opposite transversal movements of the two conveyors for their approach and departure. The resiliently yieldable connection between conveyors and female threads, on the other hand, makes it possible to estabish a certain working pressure, whether the adjustment has been made with the carton being out (in which case it is operated as in the cited U.S. patent No. 4,161,138, i.e. by positioning the two conveyors at a distance slightly smaller than the width of the carton) or the adjustment has been made with the carton being inserted (in which case it is sufficient to rotate the threaded shaft little more than necessary, so as to load the springs which provide for the yieldable connection between conveyors and female threads). By a single quick operation, therefore, there is obtained the desired adjustment, with the due working pressure, with the carton being within or out of the device as desired.

The features of the present invention will be better understood by examining the following detailed description of an embodiment thereof, which is illustrated by way of non-limiting example in the accompanying drawings, in which: Figure 1 shows a top plan view of a transport device according to the invention, employed in a sealing machine for parallelepipedal cartons; Figure 2 shows said device as sectioned along line ll-ll of Figure 1, with the conveyors being illustrated in solid lines in the position of maximum departure and in dash-dot lines in the position of maximum approach; Figure 3 shows the enlarged detail of the resiliently yieldable connection between one conveyor and the respective female thread; Figure 4 shows the same detail as sectioned along line IV-IV of Figure 3.

With reference to Figure 1, a rectangular frame 1, suitably provided with support legs, rotatably carries a succession of parallel idle rollers 2, which define a support and advancement plane 3 for the cartons to be handled (in this case, to be sealed by adhesive tape).

Two lateral uprights 4 carry at adjustable height an upper sealing head not shown in the drawings, while a similar lower sealing head is destined to be housed in an intermediate space 5 of the succession of rollers 2.

For the advancement of the cartons there are provided two belt conveyors 6, which extend along the two sides of the support plane 3 so as to be able to engage from opposite parts the side walls of the cartons.

Each of said conveyors comprises an endless belt 7, which is engaged with two pulleys 8 and 9 arranged at the ends of a succession of retaining pulleys 10, all of them rotatably carried buy a plate 11 and shielded by a cover element 12 (Figure 3).

The pulleys 8 of the two conveyors, which are those arranged more downstream in the direction of advancement of the cartons (from right to left, looking at Figure 1), are fixed to respective vertical shafts 13, which are rotatably carried by underlying rectangular plates 14 made rigid by brackets 15 to respective sleeves 16 freely slidably mounted on respective guides 17 parallel to the rollers 2 (Figure 1). To said shafts 13 there are also fixed respective sprockets 19, which receive opposite rotary motions from a stationary motor 20 through a chain system 21,22 such as that illustrated in the U.S. patent 4,161,138, to which reference is made for further details in the matter.

The pulleys 9, which are, on the contrary, those arranged more upstream in the direction of advancement of the cartons, are in turn mounted in freely rotatable manner on respective shafts 23 (Figure 3), each of which is made rigid to an underlying plate 11 and to a system of two coaxial square-section box-like bodies 24 and 25 (Figures 2 to 4), which are slidingly mounted on an internally threaded squaresection block 26 and are resiliently urged by a spring 27 to the rest position of Figure 3. The threaded block 26 operates as female thread with regard to a respective one of two oppositely inclined threaded portions 28 of a shaft 29, which is rotatably carried by the frame 1 in a position parallel to the rollers 2 and is provided with a driving crank 30.

It is apparent that, by rotating suitably the shaft 29 in one sense or the other, there is caused a corresponding mutual approach or departure of the two female threads 26, and therefore, of the conveyors 6, which are supported at the other end in freely slidable manner, as already said. In very simple and rapid way, it is thus possible to have any adjustment of distance of the two conveyors between the two end positions illustrated in solid lines and in dash-dot lines in Figure 2.

The slidable engagement between the box-like bodies 24 and 25 and the blocks 26, i.e. between the conveyors 6 and the shaft 29, and the elastic reaction of the springs 27, on the other hand, make it possible to establish a working pressure, both with a carton previously inserted between the conveyors 6 (in which case the rotation of the shaft 29 is continued beyond what is strictly necessary as much as it is sufficient to load the springs 27) and with no carton inserted (in which case the two conveyors 6 are positioned at a distance slightly smaller than the width of the carton and the desired load of the springs 27 is subsequently produced by forcing the carton between the two conveyors, possibly with the aid of suitable invitation members).

Claims

1. Transport device for variable-length parallelepipedal cartons, comprising a carton support and advancement plane, a pair of belt conveyors extending along respective sides of said support plane to engage corresponding sides of the cartons for the advancement of the same cartons along said plane and means for adjusting the mutual distance of said conveyors, characterized in that said adjusting means comprise at least one controlled rotatable shaft, which extends transversally to the carton advancement path and is provided with threaded portions with opposite inclination, which are engaged with respective female threads which bear said conveyors in axial-direction resilientlyyieldable manner.

2. Transport device according to claim 1, characterized in that each of said female threads is formed by a block slidingly housed in at least one box-like body, which extends along the axis of said shaft and supports one of said conveyors, resilient means being interposed between said block and said box-like body to urge the latter towards the center of the support plane with respect to said block.