It is known that in making shoes the shoe bottom is submitted to the action of a carding machine for eliminating the step formed on bending of the vamp edges onto the shoe bottom and for improving setting of the next vamp cementing operation.
For speeding up the different operations, automatic carding machines have been conceived on which an operator sequentially mounts the shoes to be processed. Following a predetermined program, a machine moves a head of a roughening tool along the shoe edge. When the operation has been completed, the operator takes the shoe away from the machine and mounts it again on a next automatic machine provided with a cement-applying head which also moves along the shoe bottom according to a predetermined program.
It is well apparent that the processing involves down time as a result of the continuous operations for mounting and removing shoes from the machines. In addition, the cementing head hardly follows the roughened track formed by the carding machine in an accurate and exact manner due to the unavoidable inexactitutes occurring when the shoe is mounted to the supports of the two machines.
The general object of the present invention is to obviate the above drawbacks by providing an automatic machine capable of carrying out both roughening and cementing operations, while at the same time optimizing the processing time by the simultaneous working of two shoes.
In view of the above object, in accordance with the invention as defined in claim 1, a carding-cementing machine for shoes has been conceived which comprises a pair of supports each supporting a shoe to be worked, a first and a second working head being disposed above said supports, the first working head comprising a carding tool and the second head comprising a cement-delivering tool, said supports and working heads being mutually movable so that the carding tool can travel over a predetermined path on the bottom of a shoe disposed on the first support while the cementing tool can cover a predetermined path on the bottom of a second shoe disposed on the second support, the mutual positions between the supports and the working heads being interchangeable with respect to each other so that the carding tool may be also capable of travelling over a predetermined path on the bottom of a shoe disposed on the second support, while the cementing tool can follow a predetermined path on the bottom of another shoe disposed on the first support.
For better explaining the innovatory principles of the present invention and the advantages it offers as compared to the known art, a possible embodiment of the invention putting said principles into practice will be given hereinafter by way of non-limiting example with the aid of the accompanying drawings, in which:
Referring to the drawings, as clearly shown in Fig. 1, a machine in accordance with the invention and generally denoted by 10 comprises a supporting frame 11 bearing two carriages 12, 13, each designed to receive a corresponding last or shoe to be made 14, 15 having its bottom turned upwardly.
As better shown in Fig. 2 and explained in the following, carriages 12, 13 are movable transversely of the machine extension along horizontal guide rails 16, 17. One working or carding head 18 and a second working or cementing head are present above the carriages 12, 13. The first working head 18 is movable horizontally in a direction longitudinal to the machine along guide rails 19 supported by a carriage 20 which in turn is vertically movable along guides 21 fastened to the frame 11. For example, movement of the head 18 can take place by a lead-screw unit 22 operated by an electric motor 23, whereas the vertical movement of carriage 20 can take place by means of a second lead-screw unit 24 operated by an electric motor 25.
The second working head 26 is on the contrary movable vertically along a vertical guide 27, in turn supported by a carriage 28 horizontally movable along guide rails 29 supported by the frame 11 and parallel to the guide rails 19.
For example, movement of the head 26 can take place by means of a lead-screw unit 30 operated by an electric motor 31, whereas the horizontal movement of carriage 28 can take place by means of a second lead-screw unit 32 operated by an electric motor 33.
As can be viewed from Fig. 2, the guides by which the frame supports said heads are offset with respect to each other in a horizontal direction transversely of the machine, so that mutual interferences of the heads are avoided while said heads are moving. Carriages 12, 13 supporting the shoe are power driven to be movable along the respective guide rails 16, 17 between a receded position and an advanced position which are located to the farthest right and left ends respectively, as viewed looking Fig. 2. Means for actuating carriages 12, 13, not shown for the sake of simplicity, can consist of power driven screw-lead units, as described above with reference to the working head.
It is obvious that, by moving the support carriages 12, 13, shoes can be alternately brought to intersect the vertical planes parallel to each other in which the first or second head moves.
The support carriages 12, 13 are identical with each other and comprise a base 34, 35 slidable on respective guide rails 16, 17. Each base 34, 35 carries a fixed rear support and a movable front support for the shoe. Also located on the base is a central reclining support.
Since carriages 12, 13 are identical with each other, only one carriage 12 will be described for the sake of simplicity, referring particularly to Fig. 2. As shown in said figure, the rear supporting portion 38 comprises two grippers 39 for laterally tightening the shoe heel area.
The central support portion comprises a post 36 adjustable in height, on top of which the shoe last carrying the shoe is fitted, said post being pivotally mounted at the rear part thereof according to an axis 41 enabling it to be tilted forward by means of an actuator 42, thereby moving from the upright position drawn in solid line in the figure to the inclined position drawn in chain line.
The front support portion 43 comprises a slide 44 horizontally movable along guide rails 45 parallel to the shoe extension.
The slide movement can be obtained by power driven screw-lead units not shown in the drawing for the sake of clarity.
Grippers 40 are disposed on the slide 44 for laterally tightening the toe portion of the shoe, and also provided is a locking device 46 for the shoe toe. The device 46 comprises an actuator 47 designed to move it vertically.
For loading a shoe on the support the slide 44 moves forward to the position in chain line and the central support is tilted forward for facilitating fitting (this is particularly useful in case of boots). After the shoe has been positioned on the central support 36, the latter goes back to the upright position, the slide 44 moves back towards the shoe and grippers 39 and 40 are tightened. The locking device 46 rises and entraps the shoe toe, which is therefore perfectly fixed.
The toe locking device ensures the exact positioning of the shoe relative to the working heads.
The head 18 comprises a rotating carding brush 54 movable along the periphery of the shoe bottom. Said carding head 18, being the object of an Italian patent application No.MI91A000950 in the name of the same Applicant, will not be described in detail but only enough to enable comprehension of the present invention
In particular, the head 18 comprises a slide 48 for movement along the guide rails 19. Fastened to the slide 48 is a sleeve 49 for rotation of an arm 50 about a vertical axis 51 by means of actuators 52. The arm 50 carries a second arm 53 supporting the power driven carding rotating brush 54. The arm 53 is movable in the brush plane to enable said brush to rest on the shoe bottom while exerting a predetermined pressure. The arm 53 may also be rotated by an actuating means 55 to enable tilting of the brush plane about a tangency line of the brush to the shoe, so that the brush can be kept tangent to the shoe bottom while the tool is being moved.
The axis 51 substantially passes through the contact point of the brush with the shoe bottom so that upon operation of actuators 52, the brush plane rotates through 180° about this contact point. By virtue of this, the brush, while rotating always in the same direction, has a rotatory movement at the tangency point with the shoe bottom which is always directed towards the inside of said bottom over the whole travel of the head along the shoe perimeter.
The cementing machine 26 comprises on the contrary a nozzle 56 dispensing cement in a controlled manner. Such a nozzle 56 is surrounded by a spreading brush 57 rotatably moved about the nozzle axis by a motor 58 so that cement can be uniformly distributed.
The nozzle is supported by a kinematic mechanism for its controlled tilting according to planes transverse and longitudinal to the shoe, so that the nozzle can be maintained always perpendicular to the shoe bottom while it is moving for carrying out the cementing operation.
In particular, the cementing head 26 comprises a slide 59 slidable along a vertical guide 27. Supported by the slide 59 is a first arched guide 60 extending in a plane transverse to the machine. Slidable on the arched guide 60 is a carriage 61 moved by an actuator 62 and supporting a second arched guide 63 extending in a plane longitudinal to the machine. Slidable on said second arched guide 63 is a carriage 64 driven by an actuator 65 and supporting the delivery nozzle 56.
As a person skilled in the art can easily understand, the bending centres of the arched guides are adapted to identify a rotation centre coinciding with the nozzle delivery end. In this manner, by moving the carriages on said guides, the nozzle tilts while at the same time keeping its outlet end fixed.
All actuators and mechanisms of the above machine are connected to a control device 66 substantially of known type and therefore not shown in detail as it can be easily envisaged by a person skilled in the art. For example, such a control device may be embodied by an electronic microprocessor circuit suitably programmed, as will be apparent from the following description concerning operation.
Supposing to start, in use, by loading a shoe onto the right-hand carriage 12. Once the shoe has been locked on the carriage, the carding and roughening head begins moving, carrying out lifting, lowering and left and right traverse movements, whereas the carriage 12 moves to and fro so that the brush 54 travels over a predetermined path along the shoe bottom. This path can be contained in an appropriate memory of the device 66 where it has been stored during a previous instruction step of the machine.
In particular, the brush will travel over one shoe edge and will then rotate through 180° so as to follow the opposite shoe edge. Upon the brush passing close to the shoe toe, the device 47 will retract the locking device 46, in order to let the brush freely pass, said locking device being immediately afterwards positioned in place again.
When work is over, the carding head will park in a position at which it does not interfere with the shoe and the work heads change of place relative to each other sliding along the respective horizontal guide rails.
By its own movement and the corresponding movement of carriage 12, the cement-delivering nozzle can therefore travel over its path along the shoe bottom as established, while keeping its outlet opening always tangent thereto.
While the cementing tool follows its travel path previously inputted to the control device 66, another shoe can be mounted on the left-hand carriage 13. The carding device can therefore take the predetermined path on this new shoe while the cementing operation is being completed on the first shoe.
Once the cementing operation of the first shoe has been completed, the operator can unload the shoe last from the machine. When the carding tool has finished working on the second shoe, the tools will change of place relative to each other again, so that the cementing tool will be able to cement the second shoe. In the meantime the operator will be able to load the machine with a third shoe and so forth. It will be recognized that the working process can go on uninterruptedly, without those pause periods which are typical in traditional machines for loading and unloading operations. In addition, carding and cementing operations are carried out on a shoe without moving it from the support and therefore in a very precise manner.
At this point it is apparent that the intended purposes are achieved by providing a machine of high precision and speed.
Obviously the above description of an embodiment applying the innovatory principles of the invention is for purposes of illustration only and is not limitative of the invention as defined by the appended claims. For example, the actuators may be embodied either by electric, or pneumatic or hydraulic elements. In addition, the carding head may also be a traditional head provided with two rotating brushes, disposed on either side of the shoe to be processed.