Improved drying machine, in particular for drying washing

Abstract

 A drying machine (10), in particular for drying washing, comprises a substantially horizontal drum (12), for containing the material to be dried.
The drum (12) rests on a plurality of rolls (13) with axes parallel to the axis of the drum (12). At least one of the rolls (13) is made to rotate by an electric motor (17), so as to cause the drum (12) to rotate.
A plurality of upper rolls (26) keeps the drum (12) in position on the supporting rolls (13).

Description

[0001] This invention refers to a rotary drum drying machine, in particular for drying washing.

[0002] In machines made according to the known technique, the drum containing the material to be dried is supported by a pivot protruding coaxially from the rear wall and supported cantilevered by a bearing fitted on the supporting structure of the machine.

[0003] An electric motor causes the drum to rotate, generally by means of a belt which winds peripherally around a large pulley secured coaxially to the drum, thus also creating a suitable reduction ratio between the motor and the drum.

[0004] As is easily imaginable, the pivot and the respective bearing are subjected to considerable stress, especially in the case of heavy loads to be dried.

[0005] The structure of the drum and the coupling between the latter and the pivot must be made of sturdy material, which increases the cost and the weight of the drum, resulting in a consequent increase in stress on the pivot. In order to prevent the drive belt from slipping, which is possible due to the considerable difference between its winding angle around the drum pulley and that of the motor, it is necessary to provide a tightening pulley which is difficult to adjust due also to the variability of the loads in the drum, in view of the two opposing requirements of increasing the tightness in order to transmit the torque required for moving relatively large loads of washing, and at the same time of limiting the tightness and consequent stress on the pivot supporting the drum, which is added to the stress due to the loads, and also of avoiding excessive friction when the load is small.

[0006] The general scope of this invention is to obviate the aforementioned problems as well as others that will be evident further on, by solving the problems related to the pivot support of the drum and to the transmission of motion of the latter.

[0007] This scope is achieved according to the invention by providing a drying machine, in particular for drying washing, of the type comprising a substantially horizontal drum containing the material to be dried, which is made to rotate by an electric motor, characterized by the fact that the drum is supported in the machine by resting on a plurality of rolls with axes parallel to the axis of the drum, at least one of which is made to rotate by the motor through motion transmission means.

[0008] The innovatory principles of this invention and its advantages with respect to the known technique will be more clearly evident from the following description of possible exemplificative embodiments applying such principles, with reference to the accompanying drawings, in which:

- figure 1 shows a schematic front elevation view of a drying machine made according to this invention;

- figure 2 shows a schematic side elevation view of the machine of figure 1;

- figure 3 shows a schematic front elevation view of a second drying machine made according to this invention;

- figure 4 shows a schematic side elevation view of the machine of figure 3;

- figure 5 shows a schematic partial cross-sectional view of a first detail of a drying machine made according to the invention;

- figure 6 shows a schematic partial cross-sectional view of a second detail of a drying machine made according to the invention.

[0009] With reference to the figures, a first embodiment of a drying machine, in particular for drying washing, generically indicated by reference 10 in figure 1, comprises according to the invention an external structure 11 containing a rotary drum 12 for holding the material to be dried which is placed in it through a window 19. The drum 12 is supported by simply resting on rolls 13 which rotate on supports 18 secured to the structure 11, disposed in pairs along two generatrices of the drum in a symmetrical position with respect to a vertical plane crossing the axis of rotation of the drum itself.

[0010] A pair of rolls 13 is keyed onto a common spindle 14 carrying a pulley 15 connected, by means of a belt drive 16, to an electric motor 17.

[0011] In addition to the elements described, the drying machine obviously comprises a set of devices of known technique, such as heating elements, moisture condensers, timers, thermostats, etc., which are easily imaginable by any expert technician and will therefore be neither further described nor shown, since they do not form part of this invention.

[0012] When the electric motor is turned on, the drum 12 is made to rotate due to the friction between the latter and the pair of driven rolls 13.

[0013] Figures 3 and 4 show a second possible embodiment, according to the invention, of a drying machine, in particular for drying washing, generically indicated by reference 110 and comprising within a structure 111 a rotary drum 112, containing the material to be dried which is placed in it through a window 119. The drum 112 is supported by simply resting posteriorly on idle rolls 113 (only one of which is shown in figure 4 since the other is identical and symmetrically disposed with respect to the drum 112) and anteriorly on rolls 114 driven by means of a belt 116 connected between a pulley 120 integral with one of the rolls 114 and an electric motor 117, and a second belt 121 disposed between the two rolls 114.

[0014] The rolls 113 and the rolls 114 are rotatingly mounted on supports 118.

[0015] The belt 121 is in contact with the outer edge of the drum disposed between the rolls 114, thereby permitting a satisfactory transfer of torque by friction.

[0016] Thus, when the motor 117 is turned on, the drum 112 is made to rotate in order to carry out the drying operations.

[0017] Both in the first and in the second embodiment, drum guide means are provided in order to keep the drums correctly positioned on their respective supporting rolls.

[0018] Said means can be advantageously incorporated in the supporting rolls.

[0019] For example, as shown in figure 5, the drum 12 (or 112) may comprise, along the seam between the peripheral wall 20 and the bases 21, a raised rib 22 (which may advantageously be the rib formed by the folding and seaming operation to join the base to the peripheral wall) which rests in a complementary groove 23 on the outer edge of the rolls 13 (or 113) supporting the drum, thus enabling the drum to maintain its correct axial position on the rolls.

[0020] A second example of guide means using the supporting rolls is shown in figure 6. In this case the axial guide for rotation of the drum is provided by trapezoidal grooves 24 made circumferentially on the surface of the drum 12 (or 112) to receive the complementally shaped outer edge of the rolls 13 (or 113).

[0021] Wheels 26, 126, placed in position around the drum, may also be provided to counteract, together with the supporting rolls, any sideways movements of the rotating drum and thus prevent possible shifting of the drum inside the structure of the machine, especially during the initial phases of rotation.

[0022] It is clearly evident that, in a machine made according to the invention, the supporting and moving parts are subjected to much less stress than in machines of known technique. The weight of the drum together with its contents is evenly distributed over the bearing rolls (which in the drawings are four in number but which can obviously be greater in number) and the drum itself can be made with a less sturdy structure, making the machine lighter and cheaper to produce.

[0023] Moreover, when the load in the drum is increased, the increase in weight increases the adherence of the driving rolls, or of the roll and belt assembly in the case of figure 3, which consequently always remains sufficient for rotation of the drum without slipping.

[0024] The drive belt between the motor and the pulley also has a constantly high degree of adherence without the need for special devices, since there is very little or no difference between its winding angles.

[0025] Lastly, the drying machine is quick and inexpensive to assemble due to the fact that the drum only has to be rested on the guiding and driving rolls.

[0026] The foregoing descriptions of embodiments applying the innovatory principles of this invention are obviously given merely by way of example and should not therefore be understood as a limitation to the sphere of the invention claimed herein.

[0027] For example, in the embodiment of figure 3, transmission of the movement between the drive shaft and the rolls 114 can be obtained with a single belt in place of the belts 116 and 121.

[0028] Moreover, the aperture for loading the drum can also be made on top instead of in the front as shown in the drawings, as is easily imaginable by any expert technician.

[0029] Lastly, although only some of the supporting rolls of the embodiments shown are motor-driven it is obviously possible for all the supporting rolls to be motor-driven with transmissions similar to those described.

Claims

1. Drying machine, in particular for drying washing, of the type comprising a substantially horizontal drum containing the material to be dried, which is made to rotate by an electric motor, characterized by the fact that the drum is supported in the machine by resting on a plurality of rolls with axes parallel to the axis of the drum, at least one of which is made to rotate by the motor through motion transmission means.

2. Drying machine as claimed in Claim 1, characterized by the fact that the drive means comprise a belt drive between the shaft of the motor and a spindle supporting rolls axially aligned and resting on a generatrix of the drum.

3. Drying machine as claimed in Claim 1, characterized by the fact that the drive means comprise a first belt connecting two of the plurality of rolls, disposed on two different generatrices of the drum, at least one of said two rolls being kinematically connected to the electric motor.

4. Drying machine as claimed in Claim 3, characterized by the fact that the connection between at least one roll and the electric motor is obtained by a second belt disposed between a pulley keyed onto the spindle of the roll and a pulley keyed onto the shaft of the motor.

5. Drying machine as claimed in Claim 3, characterized by the fact that the connection between at least one roll and the electric motor is obtained by an extension of said first belt which embraces a pulley keyed onto the shaft of the motor.

6. Drying machine as claimed in Claim 3, characterized by the fact that the first belt is at least partially in contact with the outer edge of the drum between the two rolls in order to transmit rotating torque to the drum.

7. Drying machine as claimed in Claim 1, characterized by the fact of comprising means for keeping the drum in position on said set of rolls.

8. Drying machine as claimed in Claim 7, characterized by the fact that the means for keeping the drum in position comprise a circumferential rib around the outer edge of the drum which slides within a complementary groove around the outer edge of the rolls.

9. Drying machine as claimed in Claim 7, characterized by the fact that the means for keeping the drum in position comprise circumferential grooves on the outer wall of the drum to receive the complementally shaped outer edge of the rolls.

10. Drying machine as claimed in Claim 9, characterized by the fact that the circumferential grooves have a substantially trapezoidal cross-section.

Drawing