GB2087830A

GB2087830A - Sweet-wrapping machine with constantly rotating twist grippers

Info

Publication number: GB2087830A
Application number: GB8132612A
Authority: GB
Original assignee: Nagema VEB
Current assignee: Nagema VEB
Priority date: 1980-11-20
Filing date: 1981-10-29
Publication date: 1982-06-03
Also published as: DE3139990C2; BR8107653A; DD153866A1; IT8149733A0; IT1172079B; DE3139990A1; GB2087830B

Abstract

The invention relates to a sweet- wrapping machine having at least one twist head, which comprises a constantly rotating and axially displaceable twist gripper 2, to which an opening and closing movement can be imparted and which is mounted in a twist head housing in which there is a drive shaft 7 for the gripper 2, which shaft is provided with a drive for generating a rotating and reciprocating movement and opening and closing movement of the gripper. Rotational drive is transmitted from the shaft 7 to a gripper shaft 4 by interengaging gears 10 and 11, and reciprocable movements of the gripper shaft 4 to accommodate wrapper shortening on twisting and of a gripper jaw opening and closing rod 3 is produced through levers 15 and 16 co-acting with respective cam tracks 14a, 14b of a cam 6, which is rotatable with the shaft 7 and axially displaceable thereon by means of a tilted two part ring 8 co-axially with the drive shaft. The inner part of the ring is connected by a ball joint 8e with the cam and the outer ring part is mounted on the head housing 1 for adjustable tilting movement so that the axial displacement of the gripper shaft 4 can be varied. <IMAGE>

Description

SPECIFICATION Sweet-wrapping machine with constantly rotating twist grippers The invention relates to a sweet-wrapping machine having at least one axially adjustably arranged twist head comprising a constantly rotating twist gripper axially displaceable in a bearing sleeve, to which gripper an opening and closing movement can be applied by means of a regulating rod situated in the interior and which gripper is mounted in a twist head housing in which, parallel with the axis of the twist gripper, there is situated a drive shaft for the latter, which drive shaft is provided with a drive system for generating a rotating, reciprocating and opening and closing motion of the twist gripper.

The known devices for twisting in the opposite ends of the wrapper of tubular form in a sweetwrapping machine work according to the same principle, irrespective of the construction. After grasping the wrapper ends the twist grippers rotate about their own axis, the wrapper ends coming closer to the sweet since a shortening of the wrapper ends occurs due to the twisting. An opening and closing movement is here superimposed upon the reciprocating movement of the twist grippers. One of the known devices consists of a primary and a secondary twist head. The secondary twist head carries out a contrarily directed displacement to the twist gripper in the primary head, the length of stroke being adapted to the corresponding requirements.The transmission of the rotating movement and axial movement is carried out separately through a tube and a connecting shaft mounted therein (GFR P.S. 1,079,533).

An improved embodiment of the last-mentioned kind comprises a main shaft arranged and axially displaceably mounted in the housing of the primary twist head parallel with the connecting shaft, which main shaft is coupled with the connecting shaft, while the twist gripper on the primary twist head is driven by the main shaft and the twist gripper on the secondary twist head is driven by the connecting shaft (GDR P.S. 46,663). These two embodiments have the disadvantage that they are usable only for wrapping machines having a primary and a secondary twist head.

An embodiment of the initially stated kind is also known which is characterised in that in the housing of the twist heads a wobble plate, having an annular groove on the circumference, is mounted on an intermediate shaft. In the annular groove of the wobble plate there engages a peg of a regulating ring which is pivotably mounted in the housing and surrounds the wobble plate. The pivot axis of the regulating ring lies in the same plane with and at right angles to the axis of rotation of the intermediate shaft. In this case the regulating ring has radial forked arms lying diametrically oppositely in the vertical plane, between which there are secured on the one side the outer sleeve of the twist grippers and on the other side a drum-type cam displaceably mounted on a shaft.In the drum-type cam there runs a cam roller which is secured at the bottom on a further regulating ring mounted in the same way. At the top, symmetrically of the axis of rotation, the regulating ring has a radial lever arm against which the axially displaceable twist gripper bears (GDR P.S.

85,304).

This embodiment, just like those described above, has the disadvantage that high technical expense must be accepted due to the necessary possibilities of adjustment for the size of packed goods and adaptation to the packing medium quality. Furthermore due to the large moved masses involved, only a limited increase of output and optimation are possible.

In order to avoid these disadvantages it is finally also known to arrange in the rear region of the main shaft a second wobble plate with a cam track machined axially externally on the circumference, against which a pivot lever, mounted in the housing and connected with the regulating rod, rests by means of a roller. Even though in the case of this embodiment the enumerated improvements have been achieved, fine tolerances must be observed in manufacture, since the two wobble plates must be adjusted to be exactly axially parallel. Even slight deviations therefrom lead to inaccurate running of the twist grippers.

The purpose of the invention is to reduce the costs in the manufacture of such a device.

The problem of the invention consists in reducing the technical expense for the generation of the reciprocating regulating movement of the twist grippers.

According to the invention this is achieved in that a ring part is mounted obliquely displaceably in the twist head housing, coaxially with the drive shaft, which part consists of an outer ring and an inner ring between which a rolling bearing is arranged, and the inner ring is articulated to a cam body axially displaceably mounted on the drive shaft, which body has two cam tracks against which there lie rollers of pivot levers mounted in the housing which are in connection with the regulating rod and bearing sleeve of the twist gripper. Thus without the use of two wobble plates the necessary regulating movements can be advantageously transmitted from the main shaft, so that manufacture is simplified and less masses have to be moved. The long-term output is thus increased and the wear, vibrations and noises are reduced.This solution also brings the advantage that by means of the cam body a superimposed regulating movement can be generated. Thus it is possible to optimalise the advance of the twist grippers in accordance with the utilised packing media.

According to a further feature of the invention the inner ring of the ring part is in transmissive connection with the cam body axially displaceable on the drive shaft, preferably through a ball joint on the inner ring and a peg on the cam body. The articulated-type connection renders possible securer running of the device.

The invention is explained in an example of embodiment in the drawing, wherein:- Figure 1 shows a longitudinal section of the twist head, Figure 2 shows a section along the line A - A in Figure 1.

For wrapping the sweets (not shown) it is also possible to use two of the twist heads as illustrated in the drawing, if a wrapping twist is desired at each end. Then the twist heads are arranged oppositely in the machine. The axial distance between the two twist heads is then variable, so that sweets of different sizes may be wrapped. The twist head as illustrated in the drawing consists essentially of a housing 1, in which a twist gripper 2 with appropriate drive system is mounted. The twist gripper 2 is arranged on the free end of a regulating rod 3 which is axially displaceably mounted in a bearing sleeve 4.

The regulating rod 3 is dimensioned so that at the other end it protrudes somewhat with a stop 5 from the bearing sleeve 4.

The bearing sleeve 4 itself is mounted rotatably and axially displaceably on plain bearings 6 in the housing 1. For the drive of the twist gripper 2 there serve a drive shaft 7 and a ring part 8 arranged coaxiallytherewith. The drive shaft 7 is mounted in the housing 1 on rolling bearings 9 and has at the front a toothed wheel 10 which meshes with a corresponding toothed wheel 11 on the bearing sleeve 4 to introduce a rotating movement. The ring part 8 is mounted obliquely displaceably in the housing 1 and consists of an outer ring 8a and an inner ring 8b, between which a rolling bearing 8c is arranged. The outer ring 8a comprises two mutually opposite radial pivot journals 8dwhich are guided in a plain bearing 12 each in the housing 1.On one side ofthe inner ring 8b there is an axially outwardly protruding ball joint 8e in which there engages a journal 13 of a cam body 14 of drum form which is axially displaceably mounted on the drive shaft 7. In the cam body 14there are machinedtwo cam tracks 14a, 14b against which regulating levers 15, 16, mounted in the housing 1, rest through rollers 15a.

The regulating lever 15 engages at the other end with a roller 15b in an annular groove 17 on the bearing sleeve 4, while the regulating lever 16 bears at its free end on the stop 5 of the regulating rod 3.

Forward by the twist gripper 2 the regulating rod 3 has a toothed segment (not shown) for the opening and closing of the twist gripper 2 and is subject to the initial stress of a spring (not shown). The inclination of the adjustably mounted ring part 8 can be adjusted and made fast from the exterior by means of a twist handle 18 secured on the journal 8d.

The manner of operation of the device is described below.

The sweets arrive by way of a wrapping wheel (not shown) in between the twist grippers 2. The twist grippers 2 move in opposite directions towards the sweet. In this movement the twist grippers 2 are opened and the open ends of the wrapper are grasped. The rotation of the twist grippers 2 leads to a twisting of these ends, whereby a shortening of the wrapper occurs. The twist grippers 2 therefore carry out a forward motion, called a stroke, also during the twisting. After the twisting of the wrapper is con cluded the twist grippers 2 open and return into their initial position. These movements of the twist grippers are achieved by the drive situated in the housing 1,the manner of operation of which maybe seen in detail from the following description.

The rotating movement of the twist gripper 2 is initiated by the drive shaft 7 through the toothed wheel 10 and the toothed wheel 11 of the bearing sleeve 4.

The axially displaceable cam body 14, which is connected through the journal 13 and the ball joint 8e with the inner ring 8b of the ring part 8, rotates with the drive shaft 7. Thus the inner ring 8b, supported in the rolling bearing 8c, is also set in rotation while the outer ring 8a non-displaceably retains its inclined position. During one revolution of the cam body 14 with the drive shaft 7 the axial distance from the ring part 8 varies. According to the illustration in Figure 1, in this position there is a slight spacing, compared with when the cam body 14 has rotated further through 180 . This variation leads to a reciprocating axial movement of the cam body 14 on the drive shaft 7. This axial movement is transmitted through the regulating levers 15, 16to the bearing sleeve 4 and regulating rod 3 respectively.The course of the cam tracks 14a, 14b is here adapted to the existing conditions, so that optimum adjustability of the twist gripper 2 is possible. The actuating movement introduced by the cam track 14a through the roller 1 spa and regulating lever 15 and the roller 1 sub to the bearing sleeve 4 effects the necessary advance of the twist gripper 2 in the twisting-in of the wrapper.

The regulating rod 3 is displaced axially from the cam track 14b through the roller 15a and regulating lever 16, whereby the twist grippers 2, mounted in toothed segments (not shown), open, and on return of the regulating lever 16 close again by spring force.

These two described actuation movements can be set afresh, in dependence upon the wrapping material to be used and the size of the sweets, in the following simple manner. On a variation of the oblique position from 0 of the ring part 8 the axial regulating path of the cam body 14 on the drive shaft 7 is also increased or decreased. This adjustment can be effected outside the housing 1, by shifting of the twist handle 18 shown in Figure 2.

Claims

1. Sweet-wrapping machine having at least one axially adjustably arranged twist head which comprises a constantly rotating twist gripper displaceable axially in a bearing sleeve, to which gripper an opening and closing movement can be imparted by means of an internally situated regulating rod and which is mounted in a twist head housing in which, axially parallel with the twist gripper, there is situated a drive shaft for the latter which is provided with a drive system for generating a rotating, reciprocating and opening and closing movement of the twist gripper, characterised in that coaxially with the drive shaft (7) a ring part (8) is obliquely displaceably mounted in the twist head housing (1), which part consists of an outer ring (8a) and an inner ring (8b) between which a rolling bearing (8c) is arranged and the inner ring (8b) of which is articu lated to a cam body (14) axially displaceably mounted on the drive shaft (7), which body comprises two cam tracks (1 4a, 14b) on which there rest rollers (1 5a) of pivot levers (15, 16) mounted in the housing, which levers are connected with the regulating rod (3) and the bearing sleeve (4) respectively of the twist gripper (2).

2. Sweet-wrapping machine according to Claim 1, characterised in that the inner ring (8b) of the ring part (8) is in transmissive connection with the cam body (14), which is axially displaceable on the drive shaft (7), this connection preferably taking place through a ball joint (8e) on the inner ring (8b) and a journal (13) on the cam body (14).

3. Sweet-wrapping machine substantially as described herein with reference to the accompanying drawings.