Step-on type tone scale play device

A step-on type tone scale play device has a flexible mat within which is arranged a plurality of flexible switch elements in accordance with a tone scale and is adapted to produce corresponding music sounds when marks configured on the surface of a mat to indicate the position of each switch element are stepped on. The device is very easy to keep and carry, and convenient to display or perform as compared to the conventional device, as the mat is light and capable of folding or rolling into a compact form.

BACKGROUND OF THE INVENTION 
The present invention relates to music play devices suitable for auditory 
training of children, and more specifically to improvements in a step-on 
type tone scale play device. 
Conventionally, a step-on type tone scale play device such as shown in FIG. 
1, exists for children, wherein step plates 2c - 2c' are arranged in 
accordance with a tone scale and are provided on a somewhat wide, high and 
rigid platform 1, and by stepping on plates 2c - 2c', corresponding music 
sounds are produced from a speaker 3. 
However, the device of FIG. 1 is not widely used because of its bulky and 
heavy platform. It is inconvenient to keep or carry, and has the 
disadvantages of being difficult to display or demonstrate for sale. It 
also has a high production cost. 
SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide a practical 
step-on type tone scale play device, in which, such disadvantages as set 
forth above are removed. 
The above object may be readily attained in a device comprising a flexible 
mat of a given width, within which is arranged a plurality of switch 
elements in accordance with a tone scale, each having a pair of oppositely 
disposed flexible conductive sheets with a flexible and resilient 
insulating cushion interposed therebetween, the insulating cushion has a 
plurality of holes, each receiving a conductive member, to form contact 
points between the conductive sheets. The flexible mat has marks on the 
surface thereof to indicate positions of said switch elements, and each of 
said switch elements are connected to control an electronic circuit and is 
adapted to close the contact points and produce a musical sound by 
stepping on a corresponding mark on said mat. 
Thus the entire part to be stepped on by foot is composed of flexible 
material, so that, even when many people walk on the mat their weight is 
supported by the floor and the mat itself is not damaged. 
Further, the device is easy to keep or carry, as the mat is light and 
capable of folding or rolling into a compact form. It can be also 
manufactured economically. 
In one embodiment of the present invention, at least one of the flexible 
conductive sheets is provided with a plurality of projections which are 
received within the holes of the flexible insulating cushion to form 
contact points. 
In another embodiment, the flexible conductive sheets are made flat and a 
piece of electric conductor is received within each of the holes of said 
flexible insulating cushion and forms a contact point. In this case, the 
mat can be fabricated more easily. 
These and other objects and advantages of the present invention will be 
apparent from the following description, the accompanying drawings and the 
appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, a step-on type tone scale play device shown 
in FIG. 2 comprises a mat 4 covered with flexible sheets such as canvas. 
On the surface thereof are figured marks 5c - 5c' indicating musical tones 
in accordance with a tone scale. Switch elements are arranged within the 
mat under each mark, and each of them is connected to an electronic 
circuit within a main box 7 by a multicore cable 6. In FIG. 2, 8 is a 
speaker, 9 is a power switch, 10 is a volume controller and 11 is the 
power cord. 
When children, for instance, step on each mark 5c - 5c', a corresponding 
music sound is produced from the speaker 8, and by stepping on the 
different marks one after another, a melody can be played. Thus an 
excellent play device for children is obtained, as the auditory sense is 
cultured naturally by the device, accompanied by some suitable physical 
exercises. 
In FIG. 3, 12 and 12' are flexible core materials of the mat 4, such as 
felt, and 13 and 13' are the cover sheets. 
14g and 14'g are a pair of flexible conductive sheets of the switch element 
arranged in the mat, each having projections on the opposed surface 
thereof, as best shown in FIG. 4. The conductive sheets 14g and 14'g are 
overlapped, with a spongy insulating cushion 15g interposed therebetween, 
whereby the projections of both sheets 14g and 14'g are received in 
corresponding holes provided in cushion 15g. 
Electro-conductive rubber may be used for the conductive sheets 14g and 
14'g, and sponge rubber, foamed polyurethane or similar flexible and 
resilient material may be used preferably for the insulating cushion 15g. 
The insulating cushion 15g should be thicker than the height of the 
projections in order to form contact gaps between the projection. 
Provision of more than several projections may be required for 
reliability. Preferably, the conductive sheets 14g, 14'g and insulating 
cushion 15g are fixed in place such as by the use of adhesive or glue. 
When the sheet 14g is stepped on, the cushion 15g is compressed and the 
opposite projections of sheets 14g and 14'g contact within the holes of 
the cushion and form the switching contact 14g which is located between 
switches 14c and 14c' of FIG. 5. The switching contacts 14g can control 
the electronic circuit in the main box 7, since the sheets 14g and 14'g 
are connected thereto by means of the multicore cable 16, ends of which 
are shown and designated 6g and 6'g respectively. 
FIG. 5 shows an example of an electric diagram of the present invention, in 
which an oscillating circuit 16 oscillates at several hundred KHz, and 
signals of one octave of music sounds corresponding to C major C.sub.4 - 
C.sub.5 are obtained by a frequency dividing circuit 17, and each of the 
signals is introduced to gate circuits 18c - 18c'. Each gate circuit 18 is 
connected to a corresponding switch element 14'c/14c - 14'c'/14c' under 
marks 5c - 5c' in FIG. 2, respectively, so as to pass the signal only when 
the corresponding switch is closed. Passed signals are introduced to a 
mixing circuit 19, and its output is amplified suitably by amplifier 20 
and volume controller 10 and produces sounds from the speaker 8. 
FIG. 6 shows another example of the mat in which the cushion 15 and core 
material 12, which is shown in FIG. 3, are made in one piece, and 
projections are provided only on the upper conductive sheets 14c - 14c', 
each received within holes provided correspondingly in the cushion 15. 
Further, the lower conductive sheets are made in one flat sheet 14' 
extending all over the mat. In this case, the thickness of the cushion 15 
should be also thicker than the height of the projections to form contact 
gaps within the holes. 
FIG. 7 shows another example of an electric diagram, illustrating the 
wiring to be used with the mat shown in FIG. 6, as well as the use of half 
tone changing switches 21c - 21c'. 
It will be understood that only melodies without sharp or flat signs in the 
staff, such as of C major or A minor can be played with the circuit shown 
in FIG. 5, but according to the circuit shown in FIG. 7, all melodies may 
be played, although the number of outputs of the dividing circuit 17 may 
increase due to including half tones. 
FIG. 8 shows a further example of an electric diagram in which 22c - 22c' 
indicate separate audio-frequency oscillating circuits, each of which is 
controlled by the corresponding switch element and which performs in a 
manner similar to the other examples. 
Mat 4 may be further provided with half tone indications as shown in FIG. 9 
like the black keys of a piano, each having a switch element thereunder. 
In this case, all melodies may be played without need of half tone 
changing switches, such as shown in FIG. 7. 
Indication of musical tone may be made not only by a letter, but also by a 
picture, which will be more familiar to the children. For instance, a 
picture of a doughnut may be used for "Do", and so on. Although only one 
octave of the tones is shown in the drawing, it may be required to 
increase this by one or more tones. 
FIG. 10 and FIG. 11 show another embodiment of the present invention in 
which the upper conductive sheets 14c - 14c' are made flat, and a 
conductive ball 23 is received within each corresponding hole provided in 
the insulating cushion 15. 
The diameter of the balls 23 should be smaller than the thickness of the 
cushion 15 to form contact gaps between the ball and the conductive 
sheets. Inexpensive material, such as electro-conductive rubber, metal, 
plated plastics, etc., may be used for the ball 23. 
The conductive sheets 14' and 14 c - 14c' should be fixed in place, such as 
by the use of adhesive or glue to seal the balls within the holes and to 
prevent the balls from coming out of the holes, and also to prevent the 
sheets moving from the place where the musical tone indication is 
configured on the surface of the mat. 
By stepping on a switch element, the conductive sheets 14c - 14c' and 14' 
communicate with each other through the conductive balls 23, and perform 
similarly as in the other examples. FIG. 12 shows other examples of 
electric conductor elements which may be used instead of balls. 
Though not shown in the drawing, quilting may be suitably applied on the 
cover sheets 13 and 13'. 
It will be seen from the above description that the device of the present 
invention is very easy to handle and can be manufactured economically. The 
mat is light and capable of being folded or rolled into a compact form. 
And, as the mat is covered with cover sheets, malfunction of the switch 
elements by the accumulation of dust may be prevented. 
By using the mat shown in FIGS. 10 and 11, the device may be manufactured 
more easily and economically, as a continuous long sheet can be used for 
the mat, and such precise alignment of the projections and holes as 
required for the embodiment shown in FIGS. 3, 4 and 6 is not required.