Shed locating devices associated with dobbies and other weaving systems

The present invention relates to improvements in shed locating devices associated with dobbies and other weaving systems. A device is provided to enable the dobby shaft to remain coupled to the loom shaft whilst being connected to an auxiliary motor and gear reducer for providing low-speed drive of the loom and the dobby for use when working on the weaving system. The same motor and gear reducer are also used during shed locating operations. The mechanisms for shifting between the normal operation of the loom and dobby, the shed locating operation, and the low speed drive of the loom and dobby are electrically controlled.

The present invention relates to dobbies and other weaving systems and more 
particularly to the devices associated with the machines of this type with 
a view to automatically locating the shed. 
In order to obtain perfect synchronism between the lifting of the heddle 
frames and the reciprocating displacement of the weft-passing member, the 
dobbies or other like mechanisms for forming the shed are known to be 
directly driven by a weaving loom itself. However, after the occurrence of 
a rupture of a weft yarn or to other weaving defect, it may be necessary 
to disconnect the dobby from the loom momentarily and to drive it in 
forward motion or in reverse motion at low speed, for one or more 
revolutions, so as to find synchronism again and allow the loom to operate 
correctly again. These momentary disconnection and slow drive operations 
are generally carried out automatically by a mechanism known as a "shed 
locating device". 
Various arrangements have, in practice, been proposed for the devices of 
this type. In the majority of cases, the connection between the shaft 
driven by the loom and the shaft of the dobby is ensured by a dog 
mechanism which enables the two said shafts to be disconnected and makes 
it possible to engage the dobby shaft with the driven shaft of a gear 
reducer driven by an auxiliary electric motor. 
The present invention relates to shed locating devices in which the dog 
mechanism is of the type such as described in Applicants' French Patent 
Application No. 78 16964 filed on May 31, 1978 which corresponds with U.S. 
Pat. No. 4,244,399. It will be seen that, in such a device, the dog 
mechanism comprises a sliding member angularly coupled to the shaft of the 
dobby and laterally provided with two opposite series of dog teeth adapted 
as a result of axial sliding of said member under the control of a rocking 
fork controlled by a cam driven in rotation by the auxiliary motor, to 
cooperate selectively with one or the other of two adjacent toothed 
plates. One of these plates rotates with the shaft of the weaving loom, 
the other with the driven shaft of the reducer associated with the 
afore-mentioned auxiliary motor. Therefore, as a function of the axial 
position of the sliding member, the shaft of the dobby is driven either by 
the loom, or by said auxiliary motor. Of course, electrical and mechanical 
means are advantageously provided during drive of the dobby by the 
auxiliary motor to stop automatically after every revolution of the shaft 
of the dobby during shed locating, so that such location is effected 
revolution by revolution in one or the other of the two directions of 
rotation of said shaft. 
It has recently been noticed that, due to the presence of an electric motor 
with reducer, these shed locating devices might advantageously be used for 
driving, not just the dobby alone after disconnection of the shaft thereof 
from the shaft of the loom: but also, after actuating appropriate control 
means, the motor and reducer can be used to slowly drive the assembly 
formed by the dobby or other mechanism and the loom itself. This general 
drive, obviously at very slow speed, proves particularly useful for 
checking the working of the assembly and/or of each of the two elements 
constituting it, or with a view to precisely adjusting one or the other of 
said elements. 
It is therefore an object of the improvements according to the present 
invention to provide the shed locating devices of the particular type 
mentioned hereinabove, with an arrangement adapted to allow the slow 
drive, when desired, of the dobby and of the loom by the motor of said 
reducer device. 
To this end, the invention consists first of providing means for achieving 
angular connection between the sliding member of the dog mechanism and the 
wheel of the reducer mechanism driven by the auxiliary motor. This 
connection is achieved by a coupling adapted to be controlled 
independently of the sliding member itself so that the latter, whilst 
remaining in the axial position in which it effects connection between the 
shaft of the loom and the shaft of the dobby, remains connected to be 
driven by the auxiliary motor through the said coupling. Furthermore, the 
device is simultaneously provided with means serving to disable the action 
of the fork and prevent it from shifting the sliding dog member despite 
the working the the auxiliary motor, so that the low-speed drive of the 
loom and the dobby is not interrupted by movement attemped to be imparted 
to said fork by the cam connected to the auxiliary motor. 
According to a preferred embodiment of the invention, the coupling 
mechanism and the disabling means are both electrically controlled so that 
they can be displaced with the aid of appropriate circuits against 
suitably arranged elastic return means.

Referring now to the drawings, the whole of the device shown in FIG. 1 is 
mounted between two vertical side frame elements 1 assembled transversly 
with respect to each other by the shaft and pin of the reducer mechanism 
of said device. This reducer mechanism comprises a bevel pinion 2 fixed on 
the driven shaft 3 of an electric motor shown schematically at 4. The 
pinion 2 meshes with a toothed wheel 5 of which the hub is provided with a 
toothing 5a which meshes with a second wheel 6. This latter is fixed on a 
shaft 7 which bears at its opposite end a pinion 8 in mesh with a third 
wheel 9. It will be readily appreciated that a considerable gearing down 
is thus obtained of the movement furnished by motor 4. 
A fixed pin 10 supports the wheels 5 and 9 and is notched to allow the 
articulated assembly of the upper end of a rocking lever 11 which is 
subjected to the action of a spring 12 so as to maintain an idle roller 
13, borne by said lever, in contact with a cam 14 mounted on the lateral 
wall of the third wheel 9 of the reducer mechanism mentioned above. As 
shown more particularly in FIG. 2 (in which reference 15 denotes the upper 
pivot pin of lever 11), the lower end of this lever is coupled to the 
upper part of a fork 16 provided with two lateral bosses or pivots 16a 
which serve to provide articulated assembly thereof on two fixed frame end 
walls 17 which laterally close the space defined by the side frame 
elements 1. 
Coupling of lever 11 and of fork 16 is effected with the aid of a 
horizontal pin or gudgeon 18 slidably introduced into holes disposed in 
alignment in the upper part of said fork and in the thinned lower end of 
the said lever. This pin 18 is urged by a spring 19 which tends to engage 
it in the afore-mentioned aligned holes. The gudgeon 18 is supported by 
the moveable core of an electromagnet 20 borne by the fork 16. Under these 
conditions, it will be readily appreciated that, when the electromagnet 20 
is energized, the pin 18 retracts so that the fork 16 is then disconnected 
from lever 11, which may thus rock independently of said fork about its 
axis 15 whilst said fork remains independently articulated upon its bosses 
or pivots 16a. 
It should be observed that, opposite the upper part of the fork 16, which 
is intended for axially controlling the sliding member of a dog mechanism 
described hereinafter, there is provided a push button switch 21 (FIG. 1) 
fixed against one of the side elements 1 and suitably connected to the 
electrical supply circuit of the motor 4, as will be seen hereinafter, 
FIG. 7. This push button switch 21 is disposed so that its mobile member 
is controlled for closure of said circuit when the fork 16, then connected 
to lever 11, rocks under the effect imparted to the latter by the action 
of the cam 14 on the roller 13. 
The dog mechanism controlled by the fork 16 is borne by a sleeve 22 which 
is axially and angularly fixed, as will be seen hereinafter, with a shaft 
23 which passes therethrough and which provides drive for the dobby. On 
the outer wall of the sleeve 22 is keyed a sliding ring member 24 which is 
thus driven in rotation with said sleeve 22 whilst being free to slide 
axially thereon. Such axial slide motion is controlled by said fork 16, of 
which each of the two arms 16b (FIG. 2) is provided with a pad 25 engaged 
in a groove 24a in ring member 24. 
Inside the ring 24 is housed a spring 26 which, abutting against an annular 
stop 27 of the sleeve 22, tends to push said ring member towards the left 
in FIG. 1. The left-hand end of said ring member 24 flares out and bears a 
series of teeth 24b longitudinally oriented so as to engage under the 
effect of the spring 26 with the corresponding teeth of a lateral dog 
plate 28a fast with a tubular shaft 28. This shaft 28 rotates freely about 
the shaft 23 (so-called "dobby shaft") and its end which projects beyond 
corresponding side element 1 bears a pulley 29 which a belt or chain 30 
connects to the weaving loom, so that this shaft 28 can be referred to as 
"loom shaft". 
It will be readily appreciated that, when the teeth 24b are in mesh with 
the dog plate 28a, the shafts 23 and 28 are thus rendered angularly 
coupled with each other. In manner known per se, the teeth 24b of ring 
member 24 and those of dog plate 28a are arranged so that, once 
disconnected from one another, one of the two shafts 23 and 28 is obliged 
to make a complete revolution with respect to the other before said teeth 
can again engage with one another (so-called drive "revolution by 
revolution"). 
As shown in detail in FIG. 3, to the rear of the ring 24, the sleeve 22 
slidably supports a bush 31 which is keyed thereto and which presents an 
annular shoulder 31a, which forms support on the one hand for an elastic 
washer 32 of conical type, on the other hand for a bearing 33. The latter 
is introduced into the axial opening of a toothed wheel 34 whose toothing 
meshes with the third toothed wheel 9 of the reducer mechanism. It should 
be observed that a ring 35 and a side element 36, connected to each other 
by screws such as 37, oblige the toothed wheel 34 to move axially with the 
bearing 33 and the bush 31. 
The ring 35 which rotates with the wheel 34 is provided with spacer 
elements 35a oriented axially and arranged in the manner of a comb to 
retain a first series of sliding friction discs 38, spaced apart from one 
another to allow insertion of and interleaved second series of sliding 
friction discs 39, the assembly of the whole being similar to that of a 
coupling device incorporating multiple discs. The discs 39 are keyed on 
the sleeve 22 and are traversed by springs 40 which abut against the 
bearing 33 and against a second ring 41 keyed on the sleeve 22. 
The toothed wheel 34 and the coupling device 38-39 are mounted in an 
opening made in one of the side elements 1, which opening receives a small 
dish-shaped cap 42 fixed in place with the aid of screws such as 43. In 
this cap 42 is housed a coil 44, arranged so that its supply of current 
ensures attraction of a plate 45 against springs 46. Between this plate 45 
and the ring 41 mentioned above is interposed a stop supporting ball 
bearings 47, slidably borne by the sleeve 22. 
It is on the axially slotted end of sleeve 22 which is disposed beyond the 
cap 42 that the clamp 48 is mounted (FIG. 1). This clamp compresses the 
slotted sleeve 22 against the shaft 23 to achieve angular and axial 
connection of said sleeve 22 and of the dobby shaft 23 on which it is 
mounted. 
Before examining FIGS. 4 to 6 which show the working of the above-described 
device, the electrical diagram thereof, as illustrated in FIG. 7, should 
be analysed. 
As shown, the coil 44 controlled through a switch 50 is connected across 
the general supply 49. This supply 49 terminates in a switch 51 adapted 
selectively to connected with said supply 49 one or the other of two 
circuits 52 and 53, which are connected to each other at a motor reversing 
switch 54 which controls motor 4 in one or the other of the two directions 
of rotation. 
Between switches 51 and 54, the circuit 52 (which, as will be seen 
hereinafter corresponds to shed locating) is interrupted by the push 
button switch 21 associated with fork 16, it being noted that this push 
button switch 21 may be short-circuited by a second manually actuated push 
button 55. Between switches 51 and 54, the circuit 53, corresponding to 
general low-speed drive, supplies across it the electromagnet 20 
associated with the retractable gudgeon 18 which ensures coupling of lever 
11 and fork 16. The use of a separate contact 51a of switch 51 avoids any 
interference between the two circuits 52 and 53 downstream of the 
electromagnet 20. 
Having explained this, reference will now be made to FIGS. 4, 5 and 6 
wherein heavy lines show the parts which are in use and light lines show 
unused parts. FIG. 4 schematically illustrates the transmission of 
movement during normal working of the loom-dobby assembly. The spring 26 
ensures meshing of teeth 24b and of plate 28b so that the movement of 
rotation of shaft 28 driven by the loom is transmitted by ring 24 to 
sleeve 22 and to the dobby shaft 23 which is driven in synchronism. The 
main switch 51 is in the neutral position shown in FIG. 7 so that the 
motor 4 receives no current. Moreover, the operator will have taken care 
to manoeuvre for closure of switch 50, so that the coil 44 is energized 
and attracts the plate 45 against the action of spring 46. The discs 38 
and 39 are therefore not gripped against one another with the result that 
they do not transmit the movement to the assembly formed by the motor 4 
and its reducer. 
When, after the weaving loom has stopped, the operator wishes to locate the 
shed revolution by revolution, he moves the main switch 51 so as to supply 
circuit 52, switch 50 being maintained in closed position. After having 
selected using the reversing switch 54 the desired direction of drive 
(forward motion or reverse motion), he presses push button 55 so as to 
supply motor 4 momentarily, this supply being maintained through push 
button switch 21 once push button 55 has been released. 
In fact, as illustrated in FIG. 5, the rotation of the shaft 3 of motor 4 
has immediately caused rocking of lever 11 under the effect of the 
rotating cam 14. The pin 18 being located in coupling position, the mobile 
member of the push button switch 21 has been pushed because of the rocking 
of the fork 16. This latter has consequently caused sliding of the ring 
24, and the axial displacement thereof towards the right against the 
spring 26 achieves disengagement of teeth 24b and of plate 28a. Shafts 28 
and 23 are therefore disconnected. 
In response to its electrical supply, the coil 44 continues to attract the 
plate 45 against the action of springs 46. However, on the other side of 
the plate by virtue of its displacement under the effect of the fork 16, 
the ring 24 has axially rightwardly pushed the sliding assembly formed by 
the washer 32, the bush 31, the bearing 33, the toothed wheel 34 (which is 
now being driven by wheel 9). Therefore the ring 35 is moved rightwardly 
and engages the discs 38 against discs 39. The rotation of shaft 3 of 
motor 4 is transmitted, with an appropriate reduction, to the dobby shaft 
23 through the coupling device 38-39. This transmission is effected one 
revolution at a time since circuit 52 is opened by cam 14 releasing the 
push button switch 21 as soon as the teeth 24b have moved angularly 
through 360.degree., but a fresh rotation may be obtained by again 
depressing the push button 55 again. 
When, for an adjustment or check, it is desired to use the shed locating 
device to ensure low-speed drive of the assembly formed by the loom and 
the dobby, the main switch 51 is actuated so as to supply the circuit 53 
of FIG. 7. The switch 50 is opened whilst the motor reverser switch 54 has 
been used to select the desired direction of drive, as in the case of FIG. 
5 corresponding to shed locating. 
As illustrated in FIG. 6, the supply of motor 4 through circuit 53 has 
rendered the electromagnet 20 live, so that the pin 18 has retracted and 
fork 16 is disconnected from lever 11. Under these conditions, the angular 
displacement of lever 11 under the effect of cam 14 no longer has any 
influence on the fork 16. Therefore, the spring 26 and the washer 32 to 
push the ring 24 leftwardly which then effects meshing of teeth 24b and 
plate 28a, so that the shafts 23 and 28 are again angularly connected to 
each other through the sleeve 22. 
Furthermore, the springs 46 have pushed axially towards the left the plate 
45 (released by the coil 44 which is no longer supplied), the stop 47 and 
the ring 41, so that the discs 38 and 39 are engaged and gripped against 
one another. The movement of rotation of shaft 3 of motor 4 is 
consequently transmitted through the reducer to the two shafts 23 and 28 
which are driven at low speed. This drive is not limited revolution by 
revolution since the push button 21 is disabled. Therefore the drive only 
stops when the operator opens the main switch 51. It will be noted that as 
soon as the device has been returned to the position corresponding to shed 
locating FIG. 5, the lever 11 will be returned to the position for which 
the pin 18, urged by its return spring 19, is in alignment with respect to 
the hole in said lever and will consequently achieve coupling of said 
lever and of fork 16 again. 
It is interesting to note that, in the event of accidental cut-off of the 
supply 49, the shed locating device according to the invention guarantees 
automatic, instantaneous blocking of the dobby. In fact, if the mechanism 
is in position of FIG. 4 corresponding to the drive of the dobby by the 
loom in normal operation, cut-off of the supply of coil 44 enables the 
springs 46 to grip the discs 38 and 39, so that the two shafts 23 and 28, 
which remain connected to each other by mesh of teeth 24a and plate 28a, 
are immobilized by the reducer mechanism (most often of the irreversible 
type) and/or by a brake 56, operating automatically by lack of current, 
advantageously associated with motor 4. 
If the mechanism is in the position of FIG. 6 (drive of the loom-dobby 
assembly at low speed), the situation is identical since the two shafts 23 
and 28, which are connected to each other, are also at the moment of 
cut-off of current angularly connected to the irreversible reducer and/or 
to the motor 4 equipped with its brake 56. 
Finally, if the mechanism is in the position illustrated in FIG. 5 (shed 
locating), the dobby shaft 23 is immobilized angularly by the reducer 
mechanism and/or the brake 56, any possible rotation of the loom shaft 28, 
which is not retained, being without practical importance at that moment. 
This automatic immobilization of the dobby in the event of breakdown in the 
general electrical supply is very useful since it radically opposes any 
untimely movement of the members of the dobby under the effect of the 
weight of the heddle frames associated therewith. 
It will be further understood that the electrical control members 50, 51, 
55 and 54 are advantageously grouped together on a common console. It goes 
without saying that the switch 50 is preferably arranged to be 
automatically actuated for closure when the main switch is taken to the 
position for which it supplies the circuit 52. 
It must, moreover, be understood that the foregoing description has been 
given only by way of example and that it in no way limits the domain of 
the invention; replacement of the details of execution by any other 
equivalents would not depart from the scope thereof. In particular, the 
coil 44 may be replaced by a jack or other pneumatically or hydraulically 
actuated thrust mechanism whose control circuit depends on an electrical 
member similar to switch 50. A coupling mechanism different from the one 
incorporating multiple discs 38-39 which has been illustrated hereinabove, 
may also be envisaged.