Spectacles frame holder

A frame holder has two jaws (1, 2) mounted so as to be slidable relative to each other in order to be movable toward or away from each other. A clamping mechanism (5) is provided for maintaining the frame (6) between the jaws in a reference plane. At least one jaw (1, 2) is provided with at least one sensor (14) which is adapted to produce a signal indicating the arrival of the jaw in a position of activation of the clamping mechanism (5) when the two jaws move toward each other. The frame holder can be used in an apparatus for analyzing rims of spectacles frames.

BACKGROUND OF THE INVENTION 
The present invention relates to a spectacles frame holder of the type 
comprising two jaws, at least one of which is slidably mounted so that the 
jaws are relatively movable toward or away from each other, and holding 
means for holding the frame between the jaws in a reference plane. 
The routing or shaping of the contour of optical glass or lenses to the 
shape of a spectacles frame requires that the shape of the frame be 
precisely entered in a computer memory. This operation is carried out by 
using an apparatus which is capable of following and analyzing the frame 
rims. 
To ensure precise contact, it is essential to correctly hold the frame in a 
stationary position during the analysis of the frame. For this purpose, a 
frame holder of the aforementioned type has been used. The holding means 
may be formed by frame-clamping clamps which are movable in a direction 
perpendicular to a reference plane, or by V-shaped centering elements 
fixed to the jaws. 
As the two jaws approach each other, the operator, in some cases, must hold 
the frame manually until it is taken hold of by the holding means. In more 
sophisticated equipment, such as that described in FR-A-2 720 524, 
retractable support rods for the frame rims are provided to facilitate the 
operation and possibly render it automatic. 
In any case, it is necessary to apply the frame against one of the jaws to 
guarantee that it is "straightened", i.e. not in an oblique position in 
the reference plane during the analyzing operation, and to avoid deforming 
the frame by the clamping thereof between the two jaws, even when the 
frame is easily deformable in its plane, as is the case with many frame 
models which have very thin metal rims. 
The known frame holders do not meet this latter condition in a reliable 
manner, and thus an object of the present invention is to satisfy this 
need. 
SUMMARY OF THE INVENTION 
The present invention therefore provides a spectacles frame holder of the 
aforementioned type, which includes at least one jaw provided with at 
least one sensor adapted to deliver a signal when the jaw reaches a 
position for activating the holding device as the two jaws move toward 
each other.

DETAILED DESCRIPTION OF THE INVENTION 
FIGS. 1 and 2 illustrate a spectacles frame holder comprising two jaws 1, 2 
which are arranged so as to be generally parallel to each other. The jaws 
1, 2 are capable of moving toward and away from each other by sliding 
along two parallel and horizontal guide rods 3 when driven by a reversible 
electric motor M. 
The frame holder further comprises two horizontal support rods 4 which are 
parallel to the rods 3. The support rods 4 are located between the rods 3 
and are laterally retractable while being maintained parallel to one 
another in accordance with the teaching of the aforementioned document 
FR-A-2 720 524. Each jaw includes a holding clamp 5 provided in the 
vicinity of an end of each rod 4 in an active position. The holding clamp 
5 may be of any suitable known type whose two jaws are vertically movable. 
In the active position, the rods 4 are adapted to support a spectacles 
frame 6 which comprises two rims 7 interconnected by a bridge 8. The jaw 1 
is adjacent to the bridge 8 and is termed an upper jaw, and the other jaw 
2 is a lower jaw. 
Lower jaw 2 is provided with a nose member 9, which is located 
substantially in a reference plane P, defined by the rods 4 in the active 
position, and midway between the rods. The nose member 9 projects toward 
the jaw 1 and has a shape which converges in the direction toward the jaw 
1. The nose member 9 is fixed to a horizontal pin 10 which is parallel to 
the rods 3 and 4 and is slidably guided in a bore 11 formed in the jaw 2. 
A weak spring 12 is disposed in a counter-bore 13 formed in the jaw 2 and 
surrounds the pin 10. The spring 12 biases the nose member 9 to the 
position illustrated in FIG. 1 which shows the nose member in a fully 
projected position relative to the jaw 2. 
Further, a position sensor 14 is located in the vicinity of the "lower" end 
of each rod 4 in the active position. The sensor 14 essentially comprises 
a vertical plate 15 which is fixed to a horizontal contact pin 16 disposed 
parallel to the rods 3 and 4 and guided in the jaw 2. A spring 17, which 
is slightly weaker than the spring 12, surrounds the pin 16 and biasing 
the plate 15 to the illustrated position in which it slightly projects 
from the jaw 2. The rear end of the pin 16 is in an opposing or facing 
relation to an electric switch 18 that is connected by wiring 19 to an 
electronic control unit 20. 
The operation of the spectacles frame holder will now be described. 
Initially (see FIGS. 1 and 2), the jaws 1 and 2 are sufficiently spread 
apart to allow the frame 6 to be placed on the rods 4. In the active 
position, the frame does not contact the nose member 9 and is completely 
outside of the four clamps 5. Also, each rod 4 is approximately in 
alignment with the middle of the associated rim 7. 
By actuating a manual switch 21, the jaws 1, 2 are driven towards each 
other in the direction of arrows F in FIGS. 1 and 2. 
In the course of the movement of the jaws, the nose member 9 initially 
comes into contact with the rims 7, and then urges the frame toward the 
jaw 1 until the bridge 8, or the two rims, depending on the frame model, 
comes into contact with the jaw 1 (FIGS. 3 and 4). 
The frame is then straightened, and as the jaws continue to move toward 
each other, the spring 12 is compressed and this produces practically no 
deformation of the frame, and then the rims 7 come into contact with the 
respective plates 15. Then, just before the jaw 2 comes into contact with 
the rims 7, the depression of the two sensors causes the pins 16 to come 
into contact with the switches 18. The resulting electric signal causes 
the control unit 20 to stop the motor M (FIGS. 5 and 6). 
In this way, it is ensured that the frame 6 is both straightened and 
non-deformed. The unit 20 then actuates the four clamps 5 which close and 
firmly hold the frame in position for the analysis thereof (FIG. 7). 
In a variation of the above-described embodiment, in order to guarantee the 
complete absence of deformation of the frame by the jaws, it may be 
arranged that the signals produced by the depression of the sensors 14 
cause, through the unit 20 and the motor M, a slight separation of the 
jaws until the signal ceases to be delivered by the sensors. 
In another variation, the clamps 5 may be actuated manually after the jaws 
have stopped moving. 
The variation illustrated in FIGS. 8 to 10 (in which the electric parts 
have been omitted) differs from the preceding embodiment only by the 
replacement of the clamps 5 by four V-shaped members 105 which are 
arranged in the same manner in a facing relation to one another in pairs. 
Two V-shaped members are fixed to the jaw 1 and the other two are fixed to 
the jaw 2. 
The position sensors 14 are disposed at the inner ends of the V-shaped 
members. The position members 14 are so arranged that contacts between pin 
16 and electric switch 18 are established when the plates 15 reach these 
inner ends. 
It will be understood that the two jaws will cease to move toward each 
other in this case when the rims 7 of the frame, after having been 
slightly raised by the V-shaped members, are just in contact with the 
inner ends of the two lower V-shaped members (FIG. 10). 
As a variation, the displacement of the jaws may be controlled manually, 
for example by a screw-and-nut system as described in the aforementioned 
document FR-A-2 720 524. The sensors 14 then deliver an optical and/or 
sound warning signal which informs the operator of the correct relative 
position of the two jaws.