Apparatus for stacking and unstacking rectangular articles such as for instance griddles, proofing pans, crates, baking pans and the like

Abstract: An apparatus for stacking and unstacking substantially rectangular articles (P), such as for instance crates or baking pans for bread, the apparatus comprising at least one guide (2a,2b) extending in the longitudinal direction of an article storage area (1), a lifting trolley (3) mobile over the guide (2a,2b) and a lifting arm (4a,4b) connected with the lifting trolley (3), which lifting arm (4a,4b) carries a lifting machine (5) extending in the width direction of the article storage area (1) and movable upward and downward above the article storage area (1) by means of the lifting arm (4a,4b), at least two guides (2a,2b) being provided, each guide (2a,2b) comprising a lifting trolley (3a,3b) with a lifting arm (4a,4b) hingedly connected with the lifting trolley (3a,3b) and referred to as swivelling arm (4a,4b), the arrangement being such that the swivelling arms (4a,4b) can each be swivelled in a vertical plane, the swivelling arms (4a,4b) being connected, at the end (12) remote from the lifting trolley (3a,3b), with the lifting machine (5,14).

Description: The invention relates to an apparatus according to the precharacterizing portion of claim 1. Such an apparatus is known from FR-A-2 652 069. The movement of the lifting trolleys along the longitudinal guides is provided by a single motor, which, via a single shaft extending between the lifting trolleys, drives two pinions which each cooperate with a rack on the respective longitudinal guides. Furhter, the lifting trolleys are connected via a frame crossbar which moves along the longitudinal guides together with the trolleys. The longitudinal guides extend at a level above the maximum stack height. The length of the swivelling arms is substantially comparable with the maximum stack height. The apparatus of the known type could for instance be used in industrial bread bakeries for manipulating baking or proofing pans that have to be temporarily stored in an article storage area and later placed elsewhere, such as for instance on a conveyor track system leading to a follow-on system such as for instance a baking oven. In a construction that is known from practice, the apparatus comprises a double guide rail construction arranged above the article storage area. The known apparatus comprises a single lifting trolley carrying a vertically arranged lifting arm that is movable upward and downward in vertical direction. At the end facing downward, the lifting arm carries a lifting machine. The lifting machine should be capable of being moved from the bottom to the desired maximum stack height. This means that the lifting arm has a length at least corresponding to the desired height of the stacks. As a consequence, when the lifting machine is at the maximum stack height, the upper end of the lifting arm is located at a height that is at least twice the maximum stack height. Hence, a substantial drawback of this apparatus is that the height of the hall wherein the apparatus is located should be at least twice the desired maximum height of the stacks. Another drawback of the known apparatus is that the length of the lifting machine is limited because the lifting machine is only supported by one single lifting arm. As a result, the maximum width of the article storage area is limited. As a matter of fact, this last drawback also applies to another apparatus known from practice, comprising a double guide rail, the separate rails of which extend in a vertical plane one above the other in horizontal direction and the double guide rail being arranged next to the article storage area. The lifting machine is connected, at one end thereof, with a lifting trolley mobile over the double guide rail. As the lifting machine is supported at one end only, the entire apparatus should be of a particularly heavy design in order to guarantee some stability. Such a heavy construction is particularly costly. The object of the invention is to provide an apparatus without the above-described drawbacks of the known apparatuses. Another object of the invention is to provide an apparatus that can readily be assembled and maintained. To that end, the apparatus of the type mentioned in the opening paragraph is characterized by the characterizing features of claim 1. Because the lifting machine is connected at the ends thereof with the swivelling arms that are hingedly connected with the lifting trolleys, the lifting machine is supported in a stable manner. Further, the lifting machine can be moved to the maximum stack height without parts of the apparatus extending far above the lifting machine. Consequently, almost the entire height of the hall or space wherein the apparatus is located can be used for forming a stack. Still another advantage of the apparatus according to the invention is that the guide will be located approximately at half the stack height. In general, this means that the guide will be located approximately at eye level, which considerably simplifies the installation and maintenance of the apparatus compared with the known apparatus wherein the guide is disposed above the -maximum stack height. Moreover, the swivelling arms are capable of pivoting through the highest point, so that the lifting machine moves between the two swivelling arms. This offers the advantage that the article storage area, i.e. the area wherein stacks can be formed, is slightly longer than, or can have at least the same length as, the guides. Further, a maximum stack height is reached with a minimum swivelling arm length, because the swivelling arms can assume the vertical position. For keeping the lifting trolleys always in a corresponding position on the guide associated with the relevant lifting trolley, the invention comprises in a preferred embodiment the features of claim 2 It is further noted that in accordance with a further elaboration of the invention, the lifting machine can be constructed in different manners. For instance, the lifting machine may comprise a single gripper that is movably connected with the lifting machine such that the gripper can be moved along the lifting machine in the width direction of the article storage area. With a lifting machine of such design, the articles can be moved in the width direction of the article storage area. In an alternative embodiment, the lifting machine can comprise at least one series of grippers by means of which a row of articles having the width of the article storage area can be picked up. By means of a lifting machine of such design, an entire row of articles having the width of the article storage area can be picked up efficiently in one lifting movement and for instance placed on a conveyor track system leading to a baking oven. Moreover, the lifting machine can comprise two or more series of grippers which may or may not be of different types, one series of grippers being movable into a pick-up position at a time through, for instance, rotation about a horizontal axis. A lifting machine of such design permits for instance articles of different types to be picked up. When the series of grippers are of the same type, the series of grippers can successively be brought into the pick-up position and pick up a series of articles, after which, subsequently, two or more rows of articles are simultaneously lifted in one single lifting movement through the swivelling operation of the swivelling arms. Thus, an apparatus of a greater processing capacity is obtained. The grippers can be constructed on the basis of different principles known per se. For instance, the gripper or series of grippers can be provided with clamping means designed for mechanical engagement with the articles to be stacked. Further, the gripper or series of grippers can be provided with pneumatic means, such as vacuum cups, for picking up the articles to be stacked and unstacked. Optionally, the grippers can be provided with electromagnetic means for picking up the articles to be stacked and unstacked. Such pneumatic and electromagnetic means have the advantage that they are more universally applicable than the mechanical means whose construction is usually adjusted to the type of article that is to be picked up by the means. On the other hand, mechanical means have the advantage that relatively heavy articles can be picked up thereby, because in that case, the operation is not based on suction force or magnetic force, but typically on the blended shapes of the mechanical means and the article to be picked up To explain the invention, an exemplary embodiment of the apparatus will be described hereinafter with reference to the accompanying drawings. In these drawings: Fig. 1 is a perspective view of an exemplary embodiment of the apparatus; Fig. 2 is a perspective view of a detail of the exemplary embodiment shown in Fig. 1; Fig. 3 is a top plan view of the exemplary embodiment shown in Fig. 1; and Fig. 4 is a side elevation of the exemplary embodiment shown in Fig. 1. The exemplary embodiment shown in perspective view in Fig. 1, in top plan view in Fig. 3 and in side elevation in Fig. 4 shows the article storage area 1 wherein the articles to be stacked, such as for instance crates, baking pans, proofing pans P or the like, are to be disposed. The stacks of articles P are arranged in rows P 1 ,...P i ,...P n , which rows P i extend in the width direction of the article storage area 1. A row P i consists of a number of juxtaposed stacks S 1 ,...S i ,...S n of articles P. The articles P are fed by one of the conveyor tracks 15, 16, temporarily stored in the article storage area 1 by means of the apparatus according to the invention and subsequently, by means of the apparatus, placed on one of the conveyor tracks 15, 16 again. The apparatus can be used in an industrial bakery for handling for instance baking pans, with the conveyor tracks 15, 16 feeding articles from or conveying them to for instance a baking oven or a proofing box or a baking pan washing station. A first conveyor track 15 can for instance feed the articles P, while the second conveyor track 16 for instance discharges the articles P again. In some cases only one conveyor belt may be sufficient, handling both the feed and discharge of the articles P. It is clear that the apparatus is also suitable for moving articles P within the article storage area 1. Disposed on two sides of the article storage area 1 is a guide 2a, 2b. Over each guide 2a, 2b, a lifting trolley 3a, 3b is mobile, which lifting trolleys 3a, 3b are each provided with a swivelling arm 4a, 4b hingedly connected with the lifting trolleys 3a, 3b. At the ends of the lifting arms 4a, 4b remote from the lifting trolleys 3a, 3b, the ends of a lifting machine 5 are mounted, which lifting machine is adapted to pick up one article or a series of articles P such as for instance baking pans. The lifting trolleys 3a, 3b comprise guide wheels 6, at least one of which can be driven via an electromotor 7a, 7b. It is clear that the drive of the lifting trolley 3a, 3b can also take place via a pinion and rack or with a drive belt. The swivelling motion of the swivelling arms 4a, 4b is obtained by means of electromotors 8a and 8b respectively. It is obvious that the apparatus comprises a drive unit which controls the electromotors 7, 8 such that the swivelling arms 4a, 4b are always in the same mutual angular position and the lifting trolleys 3a, 3b are always in a corresponding position on the guide 2a, 2b associated with the relevant lifting trolley 3a, 3b. Figs 1, 3 and 4 further clearly show cable channels 9a, 9b and cable guide means 10a, 10b containing the feed cables and control cables for the electromotors 7, 8. The guides 2a, 2b are located approximately at the level of half the stack height and are supported by for instance vertical support legs 11. It is clear that the guides can also be connected with a wall of the hall or suspended from the ceiling. A significant advantage of the apparatus according to the invention is that the construction can be rather light due to its stable structure. A further advantage is that the entire height of the hall or space wherein the apparatus is located can be utilized for stacking articles. Fig. 2 shows a detail of the exemplary embodiment shown in Fig. 1. The reference numerals of Fig. 2 that correspond to the reference numerals of Fig. 1 designate similar parts. In Fig. 2 it is clearly visible that the lifting machine 5 is hingedly connected with the swivelling arms 4a, 4b via shaft 12. In the exemplary embodiment shown, the lifting machine 5 is held in the pick-up position under the influence of gravity. However, it is apparent that when the lifting machine 5 comprises several series of grippers for picking up different types of articles P or for simultaneously picking up several series of articles P, the lifting machine 5 should be held in a desired position by means of elements present for that purpose, such as for instance a steering rod (not shown) or a separate electromotor (not shown) which determines the position of the shaft 12. Hence, the lifting machine 5 is arranged so as to be rotatable about shaft 12, enabling the desired gripper to be brought into and maintained in the desired position through rotation of the lifting machine 5 about the shaft 12. The swivelling arms 4 are each connected with the lifting trolley 3 via a shaft 13. The position of the shaft 13 is determined by the electromotors 8. The lifting machine 5 comprises a gripper or a series of grippers. In the case of a single gripper, adapted to pick up a single article, it is particularly favorable when this gripper is connected with the lifting machine 5 so as to be movable in the longitudinal direction of the lifting machine 5. The movement can for instance be effected by an electromotor controlled via the control. In this manner, it is possible to move articles P in the width direction of the article storage area 1. In the case of a series of grippers, it is possible to pick up a series of articles having the width of the series of grippers in one pick-up movement, which width will generally correspond to the width of the lifting machine 5 and hence to the width of the article storage area 1. The gripper or series of grippers are not shown in detail, because they may be of a type that is known per se. The grippers can function on the basis of mechanical (gripping fingers, gripping sections), pneumatic (vacuum cups) or electromagnetic (electromagnets) techniques. In Fig. 2, the lifting machine 5 comprises a series of grippers functioning on the basis of mechanical techniques, i.e. fingers 14 capable of engaging with the articles to be picked up.

Claims: An apparatus for stacking and unstacking substantially rectangular articles (P) such as for instance griddles, proofing pans, crates and baking pans for bread, the apparatus comprising at least two guides (2a, 2b) extending in a longitudinal direction of an article storage area (1) and disposed on two sides of the article storage area (1), each guide comprising a lifting trolley (3a, 3b) mobile over the respective guides (2a, 2b), each lifting trolley comprising a swivelling arm (4a, 4b) being hingedly connected with the respective lifting trolleys (3a, 3b), said swivelling arms (4a, 4b) each being connected, at the end remote from the lifting trolley (3a, 3b), with an end of a lifting machine (5) extending in the width direction of the article storage area (1), the arrangement being such that the swivelling arms (4a, 4b) can each be swivelled in a vertical plane such that the lifting machine (5) is movable upward and downward above the article storage area (1), characterized by two motors (8a, 8b) providing the swivelling motion of the respective swivelling arms (4a, 4b), and by a drive unit controlling the motors (8a, 8b) such that the swivelling arms are always in the same mutual angular position and that the swivelling arms can assume a vertical position thereby obtaining a maximum stack height with a minimum swivelling arm lenght. Apparatus according to claim 1, characterized in that the lifting trolleys (3a, 3b) comprise guide wheels (6), at least one of which can be driven via an electromotor (7a, 7b), the said drive unit controlling the electromotors (7a, 7b) of the lifting trolleys (3a, 3b) such that the lifting trolleys (3a, 3b) are always in a corresponding position on the guide (2a, 2b) associated with the relevant lifting trolley (3a, 3b). An apparatus according to claim 1 or 2, characterized in that the lifting machine (5) comprises a single gripper movably connected with the lifting machine (5) such that the gripper can be moved along the lifting machine (5) in the width direction of the article storage area (1). An apparatus according to claim 1 or 2, characterized in that the lifting machine (5) comprises at least one series of grippers by means of which a row of articles having the width of the article storage area (1) can be picked up. An apparatus according to claim 3 or 4, characterized in that the lifting machine (5) comprises two or more series of grippers which may or may not be of different types, one series of grippers being movable into a pick-up position at a time. An apparatus according to any one of claims 3-5, characterized in that the gripper or series of grippers comprises clamping means (14) designed for mechanical engagement with the articles (P) to be stacked and unstacked. An apparatus according to any one of claims 3-5, characterized in that the gripper or series of grippers comprises pneumatic means, such as vacuum cups, for picking up the articles to the stacked and unstacked. An apparatus according to any one of claims 3-5, characterized in that the grippers comprise electromagnetic means for picking up the articles to be stacked and unstacked.

Inventors: HIJDEN AUGUSTINUS CORNELUS V, VAN DER HIJDEN, AUGUSTINUS CORNELIS ANTONIUS
Applicants: CAPELLEVEEN BV GEB, GEBR. VAN CAPELLEVEEN B.V.
Application year: 1995
Main classification: B65G61
IPC codes: B65G61, B65G47, B65G57, B65G59