|
(11) | EP 0 726 436 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 158(3) EPC |
|
|
|
|
|||||||||||||||||||
| (54) | FEEDING SYSTEM FOR VERTICAL OVENS FOR DRYING TOPS OF CANS |
| (57) The system relates to a chain drive device (3) for displacing the supports of the
tops (1) during the drying operation, said supports consisting of buckets (2) having
longitudinal flanges coupled to the side drive chains (3) and used to support flat
tops or double bottom tops, the disclosed supply system offering the possibility to
bring closer or move away said chains in order to provide for the adaptability of
the device to the various sizes of the tops (1) which are conveyed. |
OBJECT OF THE INVENTION
[0001] In the field of machines used to varnish lids for tins is presented this invention which object consists on introducing a number of modifications into the mechanism of the ovens used to dry the lids, so that it may be possible to adapt the feeding tower, which carries the lids inside the oven, to fit their various sizes and shapes, thus achieving a greater degree of oven operation versatility.
[0002] For this to be feasible there are also scoops capable of adopting different configurations adaptable to the lids, whether they are plain or double bottomed, so as to be able to hold and carry them during the drying stage.
BACKGROUND OF THE INVENTION
[0003] At facilities used to heat up coated metal parts are well known some drying ovens made up of heating elements used to dry parts that are carried through them internally by using a conveyance mechanism made up of a rotating frame incorporating part housing plates, being further fitted with controlling devices to regulate its temperature and heating time, as well as with a device to actuate the rotating frame and an internal drying oven lifting mechanism.
[0004] Other drying ovens incorporate a conveyor belt within them used to carry the metal parts during the drying operation.
[0005] These systems present the problem that a portion of the surface of the parts being dried are in contact with the belt, carrier plates, etc., which prevents the uniform drying of said parts.
[0006] Also well known are the ovens that incorporate carrying spindles located opposite each other, fitted with channels into which fit the lids that move upward towards the upper area through the action of the rotating movement of said spindles. The lids are then transferred onto two lowering spindles, which similarly cause the lids to slide downwards towards the outlet opening.
[0007] This system suffers the problem of the obstructions that take place at the upper area when the lids move from the rising spindles to the lowering spindles, as well as the problems arising from the friction of the lids during their movement. It is also worth mentioning the vibrations caused during the operation of the device and the added difficulties posed by its having a continuous supply system.
[0008] Confronted with this circumstance, a solution is hereby advanced consisting on attaching fixed scoops, with a reduced contact surface, to a rotating device, so that the lids of the tins are held over the scoops, thus enabling a more uniform drying of said lids. Notwithstanding this, this rotating device is placed so that the distance between the scoops remains constant, enabling only the drying of lids of tins of the same size.
[0009] Are also known from the same patent holder the invention patents 921930 and 921985 that represent machines to varnish lids for tins with circular, oval, etc. shapes, in which the oven is located at the outlet of said varnishing machines, so that the lids may be dried as a continuation of the varnishing process.
DESCRIPTION OF THE INVENTION
[0010] This invention tries to solve the aforementioned problems through the adoption of a number of modifications in respect of the currently existing systems, thus allowing drying the lids of tins of various sizes and shapes, with a controlled drying time that enables the production of parts with a better finish.
[0011] The invention herein proposed consists on an oven which object is to dry the lids of the tins, after they are subjected to a varnishing or liquid rubber coating operation, basically consisting of a mechanism used to regulate the width of a feeding tower in which the lids are conveyed. Said lids remain fixed, without sliding, upon supports movable through the action of dragging chains to which they are attached, thus avoiding with this mechanism the frictions and vibrations normally generated in these devices.
[0012] It is thus possible to introduce large and small lids, of different shapes, whether square, circular or oval, thus guaranteeing a greater use of the oven as a consequence of its ease of adaptation.
[0013] The distance between the end points of the feeding tower in which are located the chains used to drag the scoops supporting the lids is regulated through the displacement of pinions on which said chains engage.
[0014] The pinions are fitted with an internal opening in which a number of stub ends are arranged, joined to the spindle that controls the distance between the pinions, through the setting of blocking clamps in the appropriate position as per the size of the lids to be dried.
[0015] Also included is the possibility of conveying into the oven lids of different configuration, whether those lids are plain or double bottomed.
[0016] In the case of plain lids, they are transported on three channelled scoops defined by four ribs that are the ones that hold the lids, having inside two of their channels holes for the passage of bolts that are used to attach the scoops to the conveyance chain. Supports with only one channel are used for the conveyance of double bottomed lids, that similarly present two holes arranged upon the ribs or projections between which is the internal channel inside which the lid is introduced.
[0017] The end chains engage onto upper and lower pinions, thus establishing the movement of each chain as per a closed cycle, determining a joint displacement of each one of the scoops associated to the chains as per the selected cycle. The lids that are introduced through the oven inlet are sequentially placed onto the corresponding scoops, one by one, being then displaced in the upward moving vertical direction until the section where the upper engagement pinion is located is reached, around which they then effect a rotating movement and later descend vertically until they reach the level of the outgoing conveyor belt, being duly deposited on the belt which then carries them outside the oven.
[0018] The lids are uniformly dried during the conveyance of each one of them across the vertical oven, maintaining the same drying intensity throughout their trip.
[0019] In order to ease the entry of the lids into the scoops, their exit towards the conveyor belt and to control the drying time, there is an adjustable transmission mechanism that determines the step by step movement of the chain so that it is duly synchronized with the oven feeding mechanism, which allows the entry into and exit from the feeding tower lid by lid. In this way it is possible to avoid the jamming problems that result from a continuous operation.
[0020] The adoption of the lid feeding system proposed by this invention allows the achievement of greater operating speed and of a number of improvements as regards the elimination of the friction and vibration normally found in other drying ovens.
DESCRIPTION OF THE DRAWINGS
[0021] In order to complement the description being effected and so as to aid a better and easier understanding of the characteristics of the invention, this patent specification includes, as an integral part thereof, a set of drawings where the following has been duly represented for purely illustrative but not limitative purposes:
Figure 1.- Represents a view of the drying oven showing the internal lay out of the feeding tower and the various transmission element.
Figure 2.- Represents a frontal view of the lids arranged upon the three channel scoops.
Figure 3.- Represents a side view of the three channel scoops arranged upon the chain.
Figure 4.- Represents an elevation view of the scoops on one channel.
PREFERRED EXECUTION OF THE INVENTION
[0022] On examining the above referred figures it may be observed that the drying ovens for varnished lids of tins is made up of a feeding tower inside which are conveyed the lids of the tins (1) arranged upon scoops (2) attached to the drag chains (3) that engage onto upper (4) and lower (5) pinions, being said pinions located across each other and capable of being displaced to spindles (6) and (7) respectively arranged inside said pinions, to which they are coupled in the position that determines the distance coinciding with the length of the lids (1) that are to be dried.
[0023] Depending upon the size of the lids (1) the upper pinions (4) are displaced outward or inward as a function of the rotation imposed onto the spindle (6), until the pinions (4) are fixed to the spindle (6) in the desired position by way of a clamp blocking system. The distance between the upper (6) pinions shall coincide with the distance between the lower (5) pinions.
[0024] The metal scoops (2) that convey the lids (1) come in two possible configurations, one of them with four longitudinal lips defining three internal channels inside which plain lids are placed, and an alternative one (2') that consists of a scoop with a sole channel adaptable so as to support double bottomed lids.
[0025] Each one of the scoops (2, 2') is fitted with holes for the passage of bolts to attach the scoops to the conveyor chain (3).
[0026] At the oven inlet and outlet are arranged conveyor belts synchronized with the movement of the chains (3), which move through the action of a step by step transmission mechanism that eases the loading and unloading of each one of the lids (1) as and when required.
[0027] It is not considered necessary to extend this description any further to enable any expert on the art to understand the scope of the invention and the advantages derived therefrom.
1. Feeding system for vertical ovens to dry lids of tins of the type fitted with drying
means for newly varnished lids, being further furnished with loading and unloading
means as well as with a feeding tower made up of two chains that are used to drag
the lid supporting parts, essentially characterized in that the dragging chains are
engaged onto upper and lower pinions, having inside both the upper and lower pinions
a rotating spindle that determines a greater or smaller separation between pinions
and which has clamps to attach the pinion to the spindle.
2. Feeding system for vertical ovens to dry lids of tins as claimed in the preceeding
claim, characterized in that the lid supporting parts, joined to the chain by conventional
joining means, consist of scoops fitted with lengthwise ribs between which lid holding
channels are defined.
3. Feeding system for vertical ovens to dry lids of tins as claimed in the preceeding
claims, characterized in that the flat lids are supported by three channelled scoops
whereas the double bottom lids are supported by scoops fitted with a single channel.
4. Feeding system for vertical ovens to dry lids of tins.
Amended claims under Art. 19.1 PCT
1. Feeding system for vertical ovens to dry lids of tins of the type fitted with drying
means for newly varnished lids, being further furnished with the loading and unloading
means as well as with a feeding tower made up of two chains that are used to drag
the lid supporting parts, engaged onto upper and lower pinions, essentially characterized
by having inside both the upper and lower pinions a rotating spindle that determines
a greater or smaller separation between pinions and which has clamps to attach the
pinion to the spindle.