GB2167724A - Apparatus for separating off incomplete stacks of long-keeping cakes, biscuits and the like - Google Patents

Abstract

In a wrapping machine in which stacks of long-keeping cakes, biscuits and particularly rusks and crackers, are fed by a chain conveyor 1 having transverse webs 1c situated across a surface 1a, to reduce the cost of operating staff on such wrapping machines, any incomplete stacks are mechanically detected and automatically separated off before they are transferred to the wrapping machine. The surface 1a has on one side a fixed abutment strip, and on the opposite side individual spring elements 3 which press the stacks against the abutment strip and, downstream of a vibrator plate 5, a spring loaded height sensor 6 and on the same side as the spring elements 3, a spring loaded length sensor 7, these sensors being followed by a raisable and lowerable bottom plate 8a, 8b in surface 1a, the bottom plate 8a, 8b being switchably connected to the height and length sensors through an electromechanical drive, e.g. electromagnet 12 and cam operated levers 9a, 9b, 9d and 10a. <IMAGE>

Description

SPECIFICATION Apparatus for separating off incomplete stacks of long-keeping cakes, biscuits and the like The invention relates to an apparatus for the mechanical scanning and subsequent separating off of incomplete stacks of articles such as long-keeping cakes, biscuits and the like, in particular crackers and rusks, which can be fed to a wrapping machine by means of a chain conveyor having transverse webs located across a conveyor belt.

It is already generally known when wrapping groups of long-keeping cakes, biscuits and the like, to have incomplete stacks removed by the operating staff or to top up these stacks in order to avoid having packages which are incorrectly filled. This manual operation is very expensive since operating staff are at all times compelled to watch the wrapping process. Also known is an arrangement for producing collective packages comprising a folding passage of variable width. Upstream of the folding apparatus is a scanning device which establishes the transverse dimensions of the material to be packed. This scanning device is kinematically linked to the transversely movable parts which laterally bound the folding passage and which serve to fold the packaging film.These parts are automatically moved into a position in which the width of the folding passage corresponds to the transverse dimension of the goods to be packaged (German Utility Model 73 27 517). This arrangement has the drawback that regardless of their size, the stacks. pass through the wrapping machine and thus differing collective packages are produced.

These collective packages can only be passed on to customers by subsequently making a price adjustment according to contents. nor is this known scanning device suitable for ascertaining the stack length of crackers, rusks and the like which, particularly in the case of incomplete stacks, come to rest untidily and obliquely in the chain conveyor and cannot be directly straightened by virtue of their rough surface.

The purpose of the invention is to reduce the cost of operating personnel used on such wrapping machines.

The problem on which the invention is based resides in mechanically detecting incomplete stacks of crackers or rusks which ar fed on a chain conveyor to a wrapping machine and separating them off automatically prior to their transfer to the wrapping machine. According to the invention, this is achieved in that the conveyor belt has on one side, bounded by a fixed abutment strip, and on the opposite side serially disposed at brief intervals, individual spring elements which press the stacks against the abutment strip and which have downstream of a vibrator plate a spring loaded height sensor mounted above the conveyor belt and a spring loaded length sensor on the same side as the spring elements, followed by a raisable and lowerable bottom plate in the conveyor belt which is switchably connected to the height and length sensors through an electromechanical drive.Advantageously, this apparatus makes it possible accurately to detect the actual quantity of individual pieces delivered. The in some cases untidily and obliquely positioned rusks or crackers in the chain conveyor are straightened up with the assistance of the vibrator plate and are transferred in a tidy arrangement to the height and length sensors.

When incomplete stacks are found, these are easily separated off downwards through a chute still before they reach the transfer station. According to a further feature of the invention, the bottom plate consists of two flap parts mounted in opposition and transversely of the conveyor belt and which can be controlled by an electro-magnet through a common lever mechanism. This embodiment can be advantageously and with minimal cost incorporated into the driving mechanism of the wrapping machine.

An embodiment of the invention is explained in greater detail hereinafter with reference to the accompanying drawings, in which: Figure 1 is a side view; Figure 2 is a plan view.

The apparatus described hereinafter for the mechanical sensing and subsequent separation off of incomplete stacks of rusks or crackers is a component part of a chain conveyor 1 which consists of a conveyor belt 1a and an endless chain 1b with transverse webs 1c. This chain conveyor 1 feeds a wrapping machine of which Figure 1 only shows the pusher-in E, the wrapping material grippers Z and afterwards the intake folders F. On the chain conveyor 1, the stacks of crackers or rusks lie transversely and are processed by the wrapping machine described while still in this transverse position. The drawing only shows the rear part of the chain conveyor 1 which embodies the solution according to the invention. In this chain conveyor 1, the stacks of rusks and crackers S are delivered by a grouping apparatus, not shown.The rear part of the chain conveyor 1 is bounded on one side by a fixed abutment strip 2. On the opposite side are firstly, and situated at brief intervals, individual spring elements 3 which press the stacks S against the abutment strip 2, and which are then, in continuation and to the end of the chain conveyor 1, constructed as a springing pressure-applying strip 3a. At the start of the apparatus, above the chain conveyor 1, there is mounted a depressor 4. Within the conveyor belt la, this is then followed by a vibrator plate 5. Behind this vibrator plate 5 there is above the conveyor belt 1a a spring loaded height sensor 6 with an initiator 6a. Disposed on the side of the spring elements 3, roughly on the same level as the height sensor 6, there is also a spring loaded length sensor 7 with an initiator 7a.In the conveyor belt la, a raisable and lowerable bottom plate 8 follows the height sensor 6 and/or length sensor 7. This bottom plate 8 consists of two flap parts 8a, 8b mounted in opposition to each other and transversely to the conveyor belt 1a. These two pivotally mounted flap parts 8a, 8b are articulated on a common lever mechanism 9. This lever mechanism is constructed from positioning levers 9a, a pull rod 9b and a pivot lever 9d mounted on a pivot spindle 9c. The bottom plate 8 or flap parts 8a, 8b are switchably connected to an electromechanical drive through the described lever mechanism 9. The electro-mechanical drive consists of a cam drive 10 and an electro-magnet 12 which actuates a ratchet mechanism 11. The lever mechanism 9 is connected to the cam drive 10 through a cam lever 10a which rolls on a cam 10e through a cam wheel 10b.The free end of the cam lever 10a rests on the ratchet 11 which is switchably connected to the electromagnet 12. This device is completed by a delivery chute 13 underneath the conveyor belt 1 for carrying away the incomplete stacks of rusks and crackers S.

The following paragraph explains how the apparatus works.

The stacks S of rusks and crackers located in the chain conveyor 1 slide on the conveyor belt la by abutment with the transverse webs 1c of the continuously driven chain 1b until these are picked up by the pusher-in E and pushed off in between the folding plates F. In the rear part of the chain conveyor 1, initially rusks or crackers which are sticking up in disorderly fashion are pressed downwards as they pass under the depressor 4 so that the stack is aligned from above. With onwards movement of the chain conveyor 1, these stacks arrive on the vibrator plate 5. Even during the next working stroke, the stacks S of rusks or crackers are disposed in the region of the vibrator plate 5 and by the action of the vibrator plate 5, obliquely positioned individual rusks or crackers become better aligned.The rusk or crackers have such a rough surface that without any assistance from the vibrator plate 5 it would not be possible for the spring elements 3 along to obtain an aligned position, particularly in the incomplete stacks. Once they have passed over the vibrator plate 5, the stacks are sufficiently tidy that they can be mechanically and reliably scanned by the following height and length sensors 6, 7. Where complete stacks are present, the height and length sensors 6, 7 do not energise the initiators 6a, 7a so that the ratchet 11 which can be actuated by the electromagnet 12 remains in the position shown in Figure 1. This means that the bottom flap 8 remains closed and at the next working stroke the stack will be positioned in front of the pusher-in E and will later pass into the wrapping machine.

If an incomplete stack passes into the range of the height and length sensor 6, 7, its position becomes changed so that the processes described hereinafter are triggered. For example, if only one cracker or rusk is missing from the stack, then only the length sensor 7 responds, whereas if the rusks or crackers are excessive in height, then the height sensor 6 is actuated. The mode of operation of the height and length sensor 6, 7 is logically the same, both alter their position and energise the associated initiators 6a, 7a which are connected to the electromagnet 12. The electromagnet 12 pulls back the ratchet 11 so that, at the next working stroke, the action of the revolving cam 10c causes the cam lever 10a to move downwards which leads to an adjustment of the lever mechanism 9 through the position lever 9a of which the two flap parts 8a, 8b are swung downwards. The incomplete or excessive stack which is resting on the conveyor belt 1a falls through in a downwards direction and is carried away by the delivery chute. At the next working stroke, the cam lever 10a is again moved into its upper position by the revolving cam 10c and the ratchet re-engages. In this way, only those stacks which meet quality requirements are subjected to the wrapping process so avoiding the wrapping machine producing incorrectly wrapped packages.

Claims (4)

1. An apparatus for the mechanical sensing and subsequent separation off of incomplete stacks of long-keeping cakes and biscuits, particularly rusks and crackers, which can be fed to a wrapping machine by a chain conveyor having transverse webs located across a conveyor belt, characterised in that the conveyor belt (1 a) is defined on one side by a fixed abutment strip (2) and has on the opposite side, disposed at brief intervals one after another, individual spring elements (3) which press the stacks (S) against the abutment strip (2) and has after a vibrator plate (5) a spring loaded height sensor (6) mounted above the conveyor belt (1a) and on the side of the spring elements (3) a spring loaded length sensor (7), sensors (6, 7) being followed by a raisable and lowerable bottom plate (8) in the conveyor belt (1) and switchably connected to the height and length sensors (6, 7) through an electromechanical drive.

2. An apparatus according to Claim 1, characterised in that the bottom plate (8) consists of two flap parts (8a, 8b) mounted in opposition to each other and transversely to the conveyor belt (lea).

3. An apparatus according to Claim 1 and 2, characterised in that the two flap parts (8a, 8b) can be controlled by an electromagnet (12) through a common lever mechanism (9).

4. An apparatus for the mechanical sensing and subsequent separation off of incomplete stacks of long-keeping cakes and biscuits as claimed in claim 1, substantially as described herein with reference to and as illustrated by the accompanying drawings.