ELECTRIC THERMAL HAIRSTYLING APPLIANCE
TECHNICAL FIELD The present invention relates to an electric thermal hairstyling appliance.
BACKGROUND ART
Electric appliances or so-called "hairstyling plates" are known, which are normally used by hairdressers to straighten, wave or otherwise heat treat hair.
In addition to professional use, domestic use of such appliances is becoming more and more widespread.
As is known, electric appliances of this sort are substantially in the form of a gripper having a handle and two arms, each fitted with a hot plate. After turning on the appliance, the user waits a few minutes for the plates to reach the required temperature, which may be regulated by a thermostat. At this point, the user simply selects a lock of hair, grips it between the heated plates, exerts pull on it to style it as required, and so on for each successive lock.
Each appliance may be equipped with a set of different pairs of plates for different functions.
For example, curly or wiry hair is normally straightened using a pair of smooth-surfaced plates; whereas waving is performed using a pair of plates, each having an undulated profile mating with a matching profile on the other plate, and the hair is gripped and waved, lock by lock, between the two electrically heated profiles . One of the drawbacks of currently used appliances lies in the interchangeable hot plates each being inserted inside a dovetail support housing an electric resistor for heating the plate and, therefore, the lock of hair gripped between the two arms of the gripper. The top surface of the dovetail support is normally provided with two lock balls subjected to the action of respective elastic means, and which engage respective cavities in the bottom surface of the hot plate, once the hot plate is positioned correctly on the support. The two lock balls, however, create a gap between the hot plate and relative support, thus preventing perfect contact between the bottom surface of the hot plate and the top surface of the support housing the electric resistor. That is, between the top surface of the dovetail support and the bottom surface of the hot plate, a gap is formed containing air which, as is known, has a much lower conduction coefficient than direct metal-metal contact.
As a result of the air gap, the hot plate takes much longer to heat to the required operating temperature, thus increasing the heat-up time of the appliance, which is an important factor, particularly when used professionally.
Moreover, very often, the hot plate has no handle, so that the user must wait for the hot plate to cool before removing it from the dovetail support and replacing it with another. DISCLOSURE OF INVENTION
It is an object of the present invention to provide an electric thermal hairstyling appliance designed to eliminate the aforementioned drawbacks .
According to the present invention, there is provided an electric thermal hairstyling appliance as claimed in Claim 1.
• BRIEF DESCRIPTION OF THE DRAWINGS
A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:
Figure 1 shows an assembly drawing of the electric thermal hairstyling appliance according to the present invention;
Figure 2 shows an exploded view of the Figure 1 appliance;
Figure 3 shows a top plan view of a smooth hot plate employed on the Figure 1, 2 appliance;
Figure 4 shows a bottom plan view of the Figure 3
hot plate.
BEST MODE FOR CARRYING OUT THE INVENTION
Number 10 in Figure 1 indicates as a whole an electric thermal hairstyling appliance in accordance with the present invention.
Appliance 10 comprises two main bodies 11, 12, which are substantially identical, except for a switch 13 and a number of LED's (not shown) on main body 11 only. The LED ' s may be used to indicate the hot plates have reached the required temperature, or to indicate any malfunctioning of appliance 10.
For the sake of simplicity, only main body 11 will be described in detail .
As shown in Figure 1, the two main bodies 11, 12 are hinged to each other by a pin 14, so that appliance 10 is substantially in the form of a gripper.
Pin 14 divides main body 11 into a handle portion 11a and a box-shaped heating member lib.
Handle portion 11a substantially houses electric wires 15 for supplying electric current to a plate 16 which acts as an electric heating resistor.
As shown in more detail in Figure 2, box-shaped heating member lib comprises an outer shell 17 preferably, though not necessarily, made of plastic material of poor electrical and thermal conductivity, and housing plate 16, and a spring 18 whose ends rest respectively on an inner surface 17a of shell 17 and on a bottom surface 16a of plate 16, for the reasons explained
in detail later on.
Plate 16 comprises a central portion 19; two walls 20, 21 perpendicular to central portion 19; and two wings 22, 23 integral with respective walls 20, 21. Central portion 19 has a top surface 19a.
Each wing 22, 23 has a recess 22a (not shown), 23a for receiving, when assembled, a respective pin 24 (not shown), 25 formed in one piece with shell 17. Pins 24, 25 act as locators for plate 16, and each have a screw 24a, 25a which screws inside a respective seat 24b (not shown) , 25b formed in respective pin 24, 25, so as to fix plate 16 to shell 17, while at the same time elastically compressing coil spring 18.
As shown in more detail in Figures 2-4, a heating plate 26 comprises a first portion 26a made of good heat- conducting metal material, such as an aluminium alloy; and a second portion 26b made of good heat-insulating plastic material .
First portion 26a has two pins 27a, 27b (Figures 3, 4) which, at assembly, are inserted by the user inside respective seats 28a, 28b formed in a wall 17b of shell 17.
As shown in Figure 2, a wall 17c, opposite wall 17b, of shell 17 has a tab 17d which, being formed in one piece with the rest of shell 17, is also made of plastic material .
Between walls 17b and 17c of shell 17, there are provided a support 29 and a catch 30, which, together
with wall 17c, defines a channel 31 which deforms slightly when a member 32 (Figures 3 and 4) is inserted inside it .
In other words, to fix plate 26 to shell 17 to form box-shaped heating member lib, the user simply inserts pins 27a, 27b inside corresponding seats 28a, 28b in wall 17b of shell 17, then rotates plate 26 about pins 27a, 27b to click member 32 on second portion 26b inside channel 31 and so lock plate 26 to shell 17. In the course of the above operation, the deformation of catch 30 when clicking member 32 inside channel 31 obviously plays an important part.
Once plate 26 is positioned, the top surface 19a of central portion 19 rests directly against a surface 26a' of portion 26a of plate 26, thus preventing, with the aid of spring 18, the formation, between plate 16 and plate 26, of undesired air gaps capable of drastically reducing the thermal conduction coefficient and so increasing the heat-up time of plate 26. • Conversely, i.e. to remove plate 26 from shell 17 , the user pushes down tab 17d with one finger, and, with another, pushes up second portion 26b of plate 26 to extract member 32 from channel 31.
Shell 17 is then ready to receive another, possibly different, plate 26 to form another box-shaped heating member lib, normally for performing a different hairstyling function.
First portion 26a,. made for example of aluminium
alloy, and second portion 26b, made of plastic material, may be connected as shown in Figure 4.
That is, on surface 26a', opposite a work surface 26a", two projections 33a, 33b are formed along the two long sides of portion 26a.
Portion 26b is fixed to projections 33a, 33b by means of two screws 34a, 34b.
So that each screw 34a, 34b can be screwed easily to respective projection 33a, 33b, each projection 33a, 33b has a respective longitudinal slot 33a' , 33b' .
The advantages of appliance 10 according to the present invention can be summed up as follows :
- heating plate 26 is easy to change, by being fastened to the supporting structure of box-shaped heating member lib using a completely different system from those currently employed; that is, unlike conventional systems normally featuring a dovetail support, the present invention employs a click-on fastening system; - plate 26 comprises a first portion 26a made of good heat-conducting metal material, such as aluminium alloy; and a second portion 26b made of poor heat- conducting plastic material, and which, being the only part gripped between the user's fingers, protects the user against burns;
- there are no elastic forces detaching plate 26 from plate 16 and so forming an undesired air gap,- on the contrary, the elastic force exerted by spring 18 on
central portion 19 keeps top surface 19a of central portion 19 resting directly against surface 26a' of first portion 26a, thus preventing the formation, between plate 16 and plate 26, of undesired air gaps capable of drastically reducing the thermal conduction coefficient and so increasing the heat-up time of plate 26.