X-Y direction input device

An X-Y direction input device used, for example, in a graphic display apparatus includes some members enclosed in a casing and requiring electrical connection to each other. The casing is divided into upper and lower cases one of which has some chamber defining walls or ribs and the other has associated projections or pins, so as to accept the members previously connected physically, electrically to each other in the respective chambers and suppressingly support them in the chambers by the projections or pins.

cl FIELD OF THE INVENTION 
This invention relates to an X-Y direction input device the most suitable 
application of which is expected in a graphic display apparatus. 
BACKGROUND OF THE INVENTION 
A graphic display apparatus basically comprises a display screen, display 
controller, data channels and some input devices. 
There are a lot of types of input devices one of which is an X-Y direction 
input device called "MAUSU" (tradename) configured to detect the moving 
direction and distance of a casing on a sheet. 
The X-Y direction input device basically comprises a rotatably supported 
ball made of steel, for example, a first follower roller contacting and 
rotated by the ball, a second follower roller contacting and rotated by 
the ball and having an axis perpendicular to the axis of the first 
follower roller, first and second rotation detectors each including rotary 
electrical members such as a variable resistor and encoder to separately 
detect rotations of the first and second follower rollers, and a casing 
which receives and envelopes the ball, first and second follower rollers, 
first and second rotation detectors and other related members. 
The casing has an aperture which opens at the bottom thereof to allow the 
ball to slightly project downward. When the casing is moved, rotating the 
ball along the sheet, the first and second follower rollers are rotated in 
predetermined different (X- and Y-) directions respectively. The amounts 
of rotation in the X- and Y-directions of the first and second follower 
rollers are detected by the first and second rotation detectors 
separately, as corresponding voltages or digital signals, and the signals 
are entered in the display apparatus. 
The first and second rollers must be rotated in the casing, maintaining a 
perpendicular relationship between their axes. In the prior art 
arrangement, the rectangular relationship of the first and second follower 
rollers are established by previously fixing the follower rollers and 
first and second rotary electrical members in position of a frame and 
thereafter securing the frame to the casing by bolts. 
Such an X-Y direction input device usually includes push switches to 
instruct deletion or dislocation of patterns displayed on the screen or to 
effect various signal processing for other switching and control 
operations. The push switch is fixed to a predetermined position of the 
casing by soldering it on a relatively hard switch board made of phenolic 
resin, for example, and thereafter securing the switch board to the casing 
by bolts. After the frame and switch board are secured to the casing, lead 
wires are soldered to lead terminals of the first and second rotary 
electrical members and terminals of the switch board to establish 
electrical connection therebetween. 
Summarizing the prior art, assemblage of the X-Y direction input device is 
significantly complicated due to the bolt fixture of the frame and switch 
board to the casing and also due to subsequent soldering in a narrow space 
inside the casing for electrical connection. 
OBJECT OF THE INVENTION 
It is therefore an object of the invention to provide an X-Y direction 
input device significantly facilitating its assemblage. 
SUMMARY OF THE INVENTION 
According to the most basic feature of the invention, a casing is provided 
with a plurality of position defining members in predetermined positions 
to closely accept first and second rotary electrical members, switch 
board, and first and second follower rollers connected to the rotary 
electrical members after physically, electrically conjoining first and 
second rotary electrical members and the switch board by a flexible 
printed circuit board. 
In a more specific feature of the invention, the casing may comprise an 
upper case and a lower case one of which has the position defining members 
and the other has a plurality of projections or pins, so that bearings of 
the first and second follower rollers and holders forming outer shells of 
the first and second rotary electrical members are closely accepted in 
chambers defined by the position defining members and are compressingly 
supported by the projections or pins. 
In another specific feature of the invention, there is provided a 
frictional force applying means which includes a compression roller 
rotatably contacting the ball, a roller support member rotatably 
supporting both ends of the axle of the compression roller, a fixture 
member rotatably supporting the roller support member by pivots located at 
one end of the support member remote from the axle of the compression 
roller, and a spring biasing the other end of the roller support member 
toward the ball. 
In a further specific feature of the invention, each rotation detector 
comprises a code plate having pattern areas and secured to and 
simultaneously rotated by the follower roller, sliders slidably 
contactable with the pattern areas of the code plate and a holder 
supporting respective ends of the sliders at a position remote from the 
code plate.

DETAILED DESCRIPTION 
The invention is hereinbelow described in detail, referring to a preferred 
embodiment illustrated in the drawings. 
FIG. 1 is a perspective of the entire system of a graphic display apparatus 
including an X-Y direction input device according to the invention. 
A table 1 supports thereon a display apparatus 2 including a screen, 
controller, data channels and others; an input device 3 having function 
keys; and an input device 4 according to the invention. The input device 4 
is moved on a sheet 5 specifically provided on the table 1, so as to move, 
for example, a cursor 7 to a desired position on a screen 6 of the display 
apparatus 2. 
FIG. 2 is an exploded perspective view of various members of the input 
device 4, and FIGS. 3 through 5 show major members of the input device 4, 
in which FIG. 3 is a bottom view of an upper case of a casing, FIG. 4 is a 
plan view of a lower case of the casing, and FIG. 5 is a plan view of a 
detection arrangement. 
A casing 8 which defines the outer margin of the input device 4 comprises a 
lower case 9 and an upper case 10 both made of ABS resin or others and 
united together by bolts (not shown). 
The lower case 9 is provided with a large aperture 11 in a rear (lefthand 
in FIG. 4), central portion thereof, and a circumferential wall 12 
standing and encircling the aperture 11. Around the aperture 11 and the 
circumferential wall 12 are provided two bearing chambers 13 and 14 and 
two holder chambers 15 and 16 slightly larger than the bearing chambers 
13, 14. These chambers define positions of follower rollers and rotation 
detectors which will be described later. One bearing chamber 13 and one 
holder chamber 15 form one associated arrangement and the other bearing 
chamber 14 and holder chamber 16 form the other associated arrangement. 
These two arrangements are located so that their center lines make a right 
angle. 
The circumferential wall 12 has a housing 17 integrally formed therewith 
and defining a chamber 17a for receiving a frictional force applying means 
which will be described later. The housing 17 has a pair of cutouts 17b at 
upper ends of opposed vertical walls thereof. 
The lower case 9 has a pair of resilient vertical projections 18 close to 
the holder chamber 15 and housing 17, and three vertical support 
projections 19 near the resilient projections 18. The resilient 
projections 18 guide insertion of a switch board (described later) into a 
position of the lower case 9, whereas the support projections 19 hold the 
inserted switch board in position. The lower case has bolt holes 20, 21, 
22 and 23 at two front positions and two rear positions. 
The upper case 10 has a dimension suitable for single-hand operation, and 
its bulging upper wall has a pair of engage holes 24 formed at a front 
position thereof. As shown in FIG. 3, a plurality of welding pins 25 
extend downward from the inner surface of the upper wall of the upper case 
10, and secure end portions of a pair of linked switch levers 26 to the 
upper case 10. This fixture is established by first engaging small holes 
of the switch levers 26 with the welding pins 25 and subsequently welding 
and cooling the end portions of the welding pins 25. Thus operational ends 
of the switch levers 26 are rotatable about the opposite fixed ends 
thereof to an extent allowed by their resiliency. The operational ends of 
the switch levers 26 slightly project through the engage holes 24 when the 
other ends are fixed to the upper case 10. 
The inner surface of the upper wall of the upper case 10 has screw holes 
27, 28, 29 and 30 at positions corresponding to the screw holes 20, 21, 22 
and 23 of the lower case 9, an annular rib 31 corresponding to the 
aperture 11, a push projection 32 corresponding to the housing 17, 
cylindrical projections 33 corresponding to the resilient projections 18, 
and a pair of push ribs 34 near the cylindrical projections 33. The inner 
surface of the upper wall of the upper case 10 has an L-shaped compression 
wall 35 one extension of which is aligned with the center line made by the 
bearing chamber 13 and the holder chamber 15 and the other extension of 
which is aligned with the center line made by the other bearing chamber 14 
and holder chamber 16. 
The chamber defined by the upper and lower cases 9 and 10 receives major 
parts of a detector arrangement shown in FIG. 5. Referring to FIG. 5, a 
switch board 36 made of a relatively hard insulative material such as 
phenolic resin has two positioning holes 36a corresponding to the 
resilient projections 18 of the lower case 9, and two push switches 37 and 
a connector 38 soldered thereon. The push switches 37 and connector 38 are 
electrically connected by a pattern wiring (not shown) formed on the rear 
surface of the switch board 36. 
The push switches 37 are used as a power switch of the input device 4 
itself and also as a signal processing switch to delete or dislocate part 
of a pattern just above the cursor 7 on the display apparatus 2 or to 
effect other switching or control operations. The display apparatus 2 and 
the input device 4 are connected by a code 39 and a plug 40 as shown in 
FIG. 1. 
A flexible firm plate 43 having a desired pattern wiring is soldered to the 
switch board 36 and the rotation detectors, i.e., the first and second 
encoders 41 and 42. First and second follower rollers 44 and 45 are 
conjoined to the first and second encoders 41 and 42, respectively. 
Therefore, the first and second follower rollers 44, 45, first and second 
encoders 41, 42 and switch board 36 supporting the push switches 37, 
connector 38 and others are physically and electrically connected by the 
flexible film plate 43 before they are mounted in the casing. 
FIGS. 6 and 7 illustrate the internal structure of the first encoder 41, in 
which FIG. 6 is an exploded perspective view, and FIG. 7 is a 
cross-sectional view of the assembled encoder. 
Referring to these drawings, the first encoder 41 includes a holder 46 
forming the outer shell of the encoder; three sliders 47a, 47b and 47c; a 
code plate 48 having a common pattern 48a in the center, an inner 
circumferential pattern 48b and an outer circumferential pattern 48c; a 
cylindrical spacer 49; and a stopper nut 50. 
The holder 46 has a planar portion 51 having one surface with a 
circumferential wall 52 and the other surface with a cylindrical bearing 
portion 53. The bearing portion 53 is formed with a projection 53a and a 
positioning projection 53b at upper and lower positions. The bearing 
portion 53 is located in a central position of the circumferential wall 52 
and defines a bearing hole 54. The planar portion 51 has a plurality of 
welding pins 51a in an area radially outward of the circumferential wall 
52 to secure ends of the sliders 47a, 47b and 47c to the planar portion 
51. Each slider 47 with one end secured by the welding pin 51a extends 
into the interior of the circumferential wall 52 through one or more 
cutouts partly breaking the circumferential wall 52. 
The first follower roller 44 has at one end thereof an engagement shaft 
portion 44b slightly smaller in diameter than the major part thereof, and 
an insertion shaft portion 44a smaller in diameter than the engagement 
shaft portion 44b. These shaft portions are inserted into the bearing hole 
54 so that the insertion shaft portion 44b enter in the circumferential 
wall 52. The insertion shaft portion 44b in the circumferential wall is 
provided with the spacer 49 and engages the code plate 48. When the 
stopper nut 50 is applied to the distal end of the insertion shaft portion 
44b, the code plate 38 is immovably secured to the first follower roller 
44. At that time, since the step defined by the different diameters of the 
major portion and the engagement portion 44a of the first follower roller 
44 abuts the peripheral edge of the bearing hole 54, whereas the inner end 
of the spacer 49 abuts a step in the bearing hole 54, the first follower 
roller 44 is axially immoved with respect to the first encoder 41. Also, 
the code plate 48 is maintained apart from the planar portion 51 by the 
spacer 49. 
When the first follower roller 44 and code plate 48 are united together 
with the holder 46 as described above, resilient contacts are established 
between first slider 47a and the common pattern 48a, between the second 
slider 47b and the inner circumferential pattern 48b, and between the 
third slider 47c and the outer circumferential pattern 48c. 
Above-described location of the fixed ends of the sliders 47a, 47b and 47c 
remote from the code plate 48 provides a long span from the fixed ends to 
the resilient contact points with the code plate 48, and provides a 
reliable sliding torque. 
The second encoder 42 has the same structure as the above-described 
structure of the first encoder 41. Repeatedly, the second encoder 42 has a 
holder 55 (FIGS. 2 and 5) forming the outer shell of the encoder; three 
sliders supported by the holder 55; and a code plate fixed to one end of a 
second follower roller 45 and contacting the sliders. The holder 55 has a 
bearing portion 56 projecting from one side thereof. The bearing portion 
56 has a projection 56a in an upper position and a positioning projection 
(not shown) in a lower position. 
The frictional force applying means which was referred to above is 
hereinbelow described, referring to FIGS. 8 and 9. 
As shown in FIG. 8, the frictional force applying means comprises a 
compression roller 57 made of a plastic resin, a roller support member 58 
supporting the compression roller 57, the housing 17 supporting the roller 
support member 58, and the coil spring 59. 
The roller support member 58 molded from a plastic resin has a pair of 
pivots 58a at upper portion of side walls, a spring support projection 58b 
(FIG. 9) at a lower position on the back surface, and a bearing portion 
58c provided in a central position between the pivots 58a and the spring 
support projection 58b and opening to the front face. A shaft 60 passes 
through the compression roller 57, and the bearing portion 58c receives 
both ends of the shaft 60 forcibly inserted therein to support the 
compression roller 57 rotatably about the shaft 60 with respect to the 
roller support member 58. 
The roller support member 58 which includes the compression roller 57 
inside and carries the coil spring 59 on the spring support projection 58b 
is inserted in the chamber 17a of the housing 17, with the pivots 58a 
entering in the cutout 17b of the housing 17 and with the coil spring 59 
contracted between the roller support member 58 and the inner wall of the 
housing 17. Due to the revival force of the coil spring 59, the roller 
support member 58 is energized clockwise about the pivots 58a, and the 
compression roller 57 supported by the roller support member 58 slightly 
projects from the housing 17 toward the aperture 11 so that the roller 
support member 58 contacts the inner wall of the housing 17 to prevent the 
roller support member 58 and compression roller 57 from inadvertently 
disengaging from the housing. 
Referring to FIGS. 10 through 12, how to assemble the input device 4 
arranged as described above is hereinbelow explained. FIG. 10 is a plan 
view of the input device 4 in which the upper case 10 is removed, FIG. 11 
is a cross-sectional view taken along the length direction of the casing 
8, and FIG. 12 is a cross-sectional view taken along the width direction 
of the casing 8. 
As shown in FIGS. 10 and 4, metal bearings 61 and 62 are applied and 
secured to the cutout 13a, 14a of the bearing chambers 13, 14 formed on 
the lower case 9. Subsequently, the preliminarily united arrangement of 
first follower roller 44, first encoder 41, second follower roller 45, 
second encoder 42 and switch board 36 (FIG. 5) is put on the lower case 9 
so that respective ends of the first and second rollers 44, 45 engage the 
metal bearings 61, 62, and the first and second encoders 41, 42 engage the 
holder acceptors 15, 16 through the guide of the positioning projections 
53b (the positioning pin of the second encoder 42 is not shown). 
Accordingly, the first and second follower rollers 44 and 45 are located 
in position of the lower case 9 so that their axes make a right angle. 
The switch board 36 is fixed in position of the lower case 9 by engagement 
between two positioning holes 36a and the resilient projections 18 of the 
lower case 9, and also supported on three support pins 19. Since the 
resilient projections 18 have axially elongated grooves 18 to form 
bifurcated ends, they never fail to engage the positioning holes 36a 
regardless of possible changes in diameter of the hole or projection due 
to drilling errors or heat deformation. 
As described, since the first and second follower rollers 44, 45, first and 
second encoders 41 and switch board 36 are mounted on the lower case 9 
after they are united together by the flexible film plate 43, they never 
come to pieces during assemblage and can be readily assembled without 
requiring post-assemblage, complicated welding. 
Subsequently, the roller support member 58 which already includes the 
compression roller 57 in position and carries the coil spring 59 on the 
spring support projection 58b is inserted in the interior 17a of the 
housing 17, with the pivots 58a engaging the cutout 17b at the upper end 
of the housing 17. The latter assemblage may precede the former of the 
first and second follower rollers 44, 45 and others. 
After the major parts of the detector arrangement are mounted in position 
of the lower case 9, as shown in FIGS. 11 and 12, the upper case 10 is put 
on the lower case 9, and they are united together by bolts (not shown) 
applied to the bolt holes 20, 21, 22 and 23 of lower case 9 and the bolt 
holes 27, 28, 29 and 30 of the upper case 10. 
When the unitary structure of the casing is established, the metal bearings 
61, 62, projections 53a, 56a of the first and second encoders 41, 42 and 
the upper walls of the holders 46, 56 are compressed by the urging wall 35 
of the upper case 10, and the first and second follower rollers 44, 45 and 
first and second encoders 41, 42 are closely sandwiched by the upper and 
lower cases 9, 10. Similarly, the lower end of the vertically extending 
push projection 32 of the upper case 10 contacts the upper surface of the 
roller support member 58 and prevents same from dropping out of the 
housing 17. Further, lower ends of the cylindrical projection 33 and 
compression rib 34 mounted on the resilient projection 18 contacts the 
upper surface of the switch board 36 so as to closely sandwich the switch 
board 36 between them and three support pins 19 vertically extending from 
the lower case 9. 
As described before, two push switches 37 are soldered to the upper surface 
of the switch board 36, whereas respective ends of two switch levers 26 
are secured to the upper wall of the upper case 10, with the operational 
portions 26a vertically extending from the lower surfaces of the switch 
levers 26. The lower surfaces of the operational portions 26a are opposed 
to the upper surfaces of the push switches 37 when the upper and lower 
cases 9, 10 are united together, so that when an operator compresses the 
switch lever 26 projecting from the upper wall of the upper case 10, the 
operational portion 26a contacts associated one of the push switches 37 to 
establish a desired switching operation. 
After the upper and lower cases 9 and 10 are conjoined, the ball 63 made of 
steel is inserted in the interior of the casing 8 through the aperture 11 
of the lower case 9. Thereafter, a cover member 64 having an aperture 64a 
is fixed along the circumference of the aperture 11 of the lower case 9 to 
rotatably hold the ball 63 in the casing 8 except small part thereof 
exposed outside, by cooperation of the circumferential rib 31 of the upper 
case 10 and a circumferential supporter 64b of the cover member 64 (FIG. 
9). 
Referring to FIG. 13, how to detect rotations in the aforegoing embodiment 
is hereinbelow explained. 
The ball 63 closely contacts the first and second follower rollers 44, 45 
due to compression from the compression roller 57. The axial direction of 
the first follower roller 44 is perpendicular to the axial direction of 
the second follower roller 45, and they contact the ball 63 from 
perpendicular directions. The compression roller 57 is located on a line 
connecting the intersection Q of the axes of the first and second follower 
rollers 44, 45 and the center 0 of the ball 63, and applies the force from 
the coil spring 59 to the ball 63 to urge same against the first and 
second follower rollers 44, 45 by an equal force. Since the roller support 
member 58 rotatably supporting the compression roller 57 is supported by 
the housing 17 pivotably about the pivots 58a, rotation of the ball 63 
never invites a positional deviation of the axle 60 of the compression 
roller 57 and pivots 58a, and the ball 58 always receives a well-balanced 
force from the compression roller 57. 
To respective ends of the first and second follower rollers 44, 45 are 
connected the first and second encoders 41, 42 which detect rotation 
amounts of the first and second follower rollers. In this way, rotation of 
the ball 63 is detected, separating it in X- and Y-directional components. 
Summarizing the invention, the first and second rotary electrical members 
conjoined to the first and second follower rollers and the switch board 
carrying the push switches are preliminarily connected electrically and 
mechanically into a single unit by the flexible printed board before they 
are mounted in the casing configured to define specific positions of the 
these members. Therefore, the single unit never falls to pieces while it 
is mounted in the casing, and soldering connection of the printed board to 
the rotary electrical members and switch board can be effected in a free 
space outside the casing before it is entered in same. 
The invention has succeeded in omission of specific frames used in the 
prior art device to envelope in-casing members and omission of bolts used 
to fix the frames to the casing, by employing the arrangement wherein the 
bearings supporting the first and second follower rollers and the holders 
forming outer shells of the first and second rotary electrical members are 
accepted in positions specifically defined by the positioning means of the 
upper or lower case and are closely sandwiched between both cases when the 
cases are conjoined. 
The frictional force applying means used in the invention device comprises 
the compression roller rotatably compressing the ball, roller support 
member rotatably supporting both ends of the axle of the compression 
roller, the fixture member rotatably supporting the roller support member 
at one end thereof remote from the axle of the compression roller, and a 
spring provided at the other end remote from the shaft to bias the roller 
support member toward the ball. This arrangement significantly reduces the 
possibility that the shaft of the compression roller and the pivots of the 
roller support member deviate during rotation of the ball, and never fails 
to compress the ball to the first and second follower rollers by an even 
force. This provides a significantly accurate detection in the X-Y 
direction input device. 
Each rotation detector comprises a code plate having some pattern areas and 
secured to and concurrently rotated by the follower roller, sliders 
slidably contactable with the pattern areas of the code plate, and a 
holder supporting respective ends of the sliders, locating the junctions 
of the sliders with respect to the holder at a position remote from the 
code plate. Therefore, the span of each slider from the secured point up 
to the contactable point may be elongated as desired to reduce the sliding 
torque.