Patent Application
20210086252
The present invention relates to a belt drive unit for a molding machine of bored fins, in particular for heat exchangers, with controlled adaptability to bores of different diameters.
Molding machines for bored fins for heat exchangers are known particularly from US 2012/216664 A1, in which a metal belt is moved forward into the machine, where there is a boring unit which provides for making bores in pre-established areas of the metal belt, previously drawn, to obtain bored collars intended for the passage of the heat exchanger tubes. At the exit of the molding machine, a cutting unit is provided, which carries out transverse cutting operations of the belt to divide the belt itself into single bored fins.
To allow the sequential execution of the various drawing, molding and cutting operations, and possibly others, the metal belt is moved forward stepwise with forward movement pauses corresponding to the positioning of predetermined areas of the belt first inside the drawing unit, then inside the boring unit and finally at the cutting unit.
The forward movement of the belt is carried out by a drive unit with alternating forward and backward movement, which is provided between the boring unit and the cutting unit with the task of dragging the bored belt forwards, positioning it appropriately and then leaving it in the position reached, which is suitable for cutting it by means of a cutter, finally returning to a suitable position for the next driving operation.
For this purpose, the drive unit usually comprises a fixed front part and a movable rear part driven longitudinally with a forward and backward movement to and from the fixed front part. Both parts of the drive unit include support plates on the upper surfaces thereof for vertical teeth with movable oblique top which protrude upwards under elastic thrust and are suitable for being inserted into corresponding bored collars of the belt downstream of a boring unit. The teeth of the movable rear part drive the belt forward during the forward movement of said movable rear part to then lower it below the plane of the belt and leave it in the position reached during the next backward movement of the same movable rear part, while the teeth of the fixed front part keep the belt in the position reached, which is suitable for the next cutting operation, during the step of moving backward the movable rear part.
This mode of operating the drive unit is fully satisfactory as long as the diameter of the bored collars of the fins remains constant. The problem arises when the same machine is used for molding belts and consequent fins with bored collars of larger diameter. In this case, the same teeth for moving forward and positioning the belt are obviously not usable in combination with larger collars. It is then necessary to modify the drive unit so as to allow it to use plates with teeth of correspondingly increased diameter. This currently requires the intervention of specialized operators who perform the partial or total removal and replacement of the plates with teeth. A similar intervention is necessary for the transition from a belt with bored collars of larger diameter to a belt with bored collars of a smaller diameter, which are obviously not able to receive teeth intended for larger bored collars.
Faced with this problem, it was the object of the present invention to facilitate, speed up and associate with a simple command the passage of the machine from molding fins with smaller diameter bores to molding fins with larger diameter bores, and vice versa, while avoiding complex replacement or movement maneuvers to be performed directly on the drive unit.
According to the present invention, this object is achieved by providing the upper surfaces of each of the two movable and fixed parts of the drive unit with at least a further support plate for movable vertical teeth with oblique top of larger diameter, which is liftable and lowerable by a control panel compared to that with smaller diameter teeth to replace the teeth thereof with those previously used for moving forward and positioning the belt.
Thereby, the operating passage from obtaining fins with small diameter bores to obtaining fins with larger diameter bores, or vice versa, can occur by producing with a simple command the lifting or lowering, respectively, of the plates with teeth of greater diameter above or below the operating plane of the plates with small diameter teeth, respectively. The intervention of toolmakers is not necessary, because an external command given by the operator responsible for controlling the machine is sufficient.
The features and advantages of the present invention will become apparent from the following detailed description of a possible embodiment thereof, shown by way of non-limiting example in the accompanying drawings, in which:
With reference to
The molding machine includes, at the exit thereof, a drive unit 4 for the belt 3 and a cutting unit 5 which, by means of a cutter 6, divides the belt 3 into a plurality of single bored fins intended for the formation of heat exchangers or other.
The drive unit 4, which forms the object of the present invention, can be of various shapes and sizes but essentially comprises a fixed base 8, in turn fixed to the general base 9 of the molding machine, and an openable cover 10, as shown in
Exemplary forms of the base 8 of the drive unit 4 are shown in
As shown in
In a completely similar manner, the upper surface of the movable rear part 13 includes plates 31 and 32 side by side with respect to the forward direction of the belt 3, which support respective cylindrical vertical teeth 35 and 36 with oblique tops 37 and 38, identical to the teeth 20 and 21 of the fixed front part 12, which teeth 35 and 36 are slidably housed in respective cylindrical vertical bores 33 and 34 of the support plates 31 and 32. The teeth 35 are pushed upwards by respective reactant springs 39 inside cavities 40 of the movable rear part 13, while the teeth 36 are pushed upwards by reactant springs 41 inside cavities 42 of an intermediate plate 43 integral with the upper plate 17 and movable upwards therewith, against the action of a retaining spring 44, by introducing fluid into an underlying compartment 45.
The teeth 20 and 21 also pass through respective circular bores 46 and 47 of the upper flat plate 11, while the teeth 35 and 36 are housed in a longitudinally sliding manner inside elongated slots 48 which extend in the longitudinal direction defined by the forward direction F of the belt 3.
Longitudinal channels 49 are provided in the lower surface of the cover 10 to accommodate and delimit the vertical lifting of the teeth 21, 22, 35, 36 during the driving and positioning operation.
Finally, a remote control system is associated with the drive unit 4, the main diagram of which is shown in
The structure described above gives rise to the following operating method of the drive unit 4 and more generally of the molding machine which comprises it.
A metal belt 3 exits the boring unit 2 provided with bored collars 52 which are arranged according to the positioning diagram of the teeth 21, 22, 35, 36 of the drive unit 4 and have a diameter which can be varied between two predetermined values (referred to here as “smaller diameter” and “greater diameter”) by conveniently acting, in a known manner, on the boring unit 2 and possibly on the drawing unit which precedes it. As the aforesaid diameter varies, it is necessary to act on the drive unit 4 in a corresponding manner The control system in
If the belt 3 has been bored with smaller diameter bores, the smaller teeth 35 of the movable rear part 13 of the drive unit carry out the dragging of the belt, which are inserted into the bored collars 52 of the belt when in a backward position as in
During this operation, carried out repeatedly to move forward the belt 3 step by step and bring subsequent portions of the belt itself to the cutting unit for the subdivision into single bored fins, the operator of the machine kept the control panel 50 in condition such as to remove the operating fluid from the compartments 30 and 45 and allow the springs 29 and 44 in
If the machine is switched so as to bore the belt with larger diameter bores, the operator can easily switch the drive unit 4 accordingly, by acting on the control panel 50 so as to command the control unit 51 to introduce pressurized fluid into the compartments 30 and 45 to bring the intermediate plates 28 and 43 into the lifted position and therewith the teeth 22 and 36 of greater diameter, which can thus be inserted into the bores of the belt to cause the repeated forward movement of the belt step by step in the same manner as already described for the case of smaller diameter bores.
In a similar manner, by unloading the pressurized fluid from the compartments 30 and 45 by a command given by the operator to the control panel 50, it is possible to return the drive unit to the operating condition for the belt with smaller diameter bores.
The operator only has to act conveniently on the control panel 50 without carrying out operations of assembling or disassembling parts of the
| Number | Date | Country | Kind |
|---|---|---|---|
| 102019000016766 | Sep 2019 | IT | national |
