US3866482A

US3866482A - Drive system for reed roller of weaving machine

Info

Publication number: US3866482A
Application number: US380064A
Authority: US
Inventors: Walther Filter
Original assignee: Voestalpine AG
Current assignee: Voestalpine AG
Priority date: 1972-08-08
Filing date: 1973-07-17
Publication date: 1975-02-18
Anticipated expiration: 1992-02-18
Also published as: FR2195717B1; SU480220A3; FR2195717A1; CA975250A; BE802970A; DD105267A5; JPS5035468A; AT316448B; DE2337050A1; GB1397037A; CS163707B2; CH555429A

Abstract

The drive system for intermittently rotating a reed roller incorporated in a flat weaving machine comprises a unidirectionally rotatable mounted reed shaft which is corotationally connected to said reed roller. A torsion bar is coaxial with said reed shaft and has first and second ends and at said first end is corotationally connected to one end of said reed shaft. A one-way coupling operatively connects actuating means to said second end of said torsion bar. Said actuating means are operable to rotate said second end of said torsion bar in a predetermined sense by means of said one-way coupling. A ratchet wheel is corotationally connected to said reed shaft. A locking pawl is movable into and out of locking engagement with said ratchet wheel. Holding-down means serve to hold said locking pawl in locking engagement with said ratchet wheel to hold said reed shaft against rotation during said rotation of said second end of said torsion bar in said predetermined sense by said actuating means.

Description

1 51 Feb. 18, 1975 United States Patent [191 Filter [54l DRIVE SYSTEM FOR REED ROLLER OF 3,300,697 1/1967 Woodford....v.v.n..v...........i,... 74/128 WEAVING MACHINE 3 705 606 12/1972 139/188 FOREIGN PATENTS OR APPLICATIONS [75] Inventor: Walther Filter, Langenhagen,

Germany 173] Assignees: Vereinigte Osterreichisehe v Eisemund Stahlwerke A|pine Primary ExammerVl/esley Sv Ratliff. Jr. Montan Akfiengesenschaft, Vienna, Attorney, Agent, or Firm-Kurt Kelman Austria; Establissement Wanderfield & C0., Schaan. Liechtenstein July 17, 1973 Appl. No.: 380,064

[57] ABSTRACT The drive system for intermittently rotating a reed rol- [22] Filed:

ler incorporated in a flat weaving machine comprises a unidirectionally rotatable mounted reed shaft which is corotationally connected to said reed roller. A torsion [30} Foreign Application Priority Data bar is coaxial with said reed shaft and has first and second ends and at said first end is corotationally connected to one end of said reed shaft. A one-way coupling operatively connects actuating means to said Aug. 8. 1972 Austria 6849/72 second end of said torsion bar. Said actuating means [51] Int 0 1324.33; are operable to rotate said second end of said torsion bar in a predetermined sense by means of said oneway coupling. A ratchet wheel is corotationally connected to said reed shaft. A locking pawl is movable into and out of locking engagement with said ratchet wheel. Holding-down means serve to hold said locking 5 2H 9 ,3 71 9., ,7 5 U7 6 2 .18 M2 1 m2 4 2 9 MS 9 m7 mm 2 1 .w F 8 5 pawl in locking engagement with said ratchet wheel to hold said reed shaft against rotation during said rota- 139/188 R tion of said second end of said torsion bar in said pre- 1 451 4? determined sense by said actuating means.

139/145 8 Claims, 4 Drawing Figures Pusateri Mattox 11/1957 Pfarrwaller 3/1964 Wohlgemuth et al.

F/JENTED FEB 1 8 1975 SHEET 1 OF 4 SHEET a 4 82 PATENTED FEB I 81975 2 h E EEL EQEEE m a n m \\\\\S DRIVE SYSTEM FOR REED ROLLER OF WEAVING MACHINE This invention relates to a drive system for intermittently rotating a reed roller of a flat weaving machine, in which the reed consists ofa multiplicity of thin discs, which are aligned on a common shaft and are provided with dogs.

In machines comprising such reed, the filling thread which has been inserted into the shed is engaged by the dogs of the several reed discs and, as the reed shaft is rotated, the filling thread is beaten up against the fell of the cloth. So far, the intermittent rotation has been imparted to the reed shaft by means of a crank mechanism or maltese crosses; this has the disadvantage that the rotation is not fast enough and does not result in a sufficiently strong impact of the filling thread and the drive dogs on the fell of the cloth. A hard impact is particularly advantageous when it is desired to provide a large number of filling threads per inch in heavy woven fabrics. In connection with pickers it is known (Austrian Pat. No. 183,034, Printed German Application No. 1,535,686) to connect the picking arm to a torsion spring so that the picking force is exerted as a result of the unwinding of the torsion spring which is adapted to be wound by a coaxial tube. As a result, the picking arm drives the shuttle through the shed. These mechanisms serve to drive bodies continuously along a straight line rather than to drive intermittently rotating bodies.

It is an object of the invention to provide a drive system which serves to impart an intermittent rotation to a reed shaft and which ensures a fast working movement and a strong impact of the filling thread whereas the system has a relatively small space requirement and a simple structure. Besides, the system is designed to make possible a change of the impact force exerted by the filling thread even while the weaving machine is in operation.

This object is accomplished according to the invention with a reed shaft which is corotationally connected to one end ofa coaxial torsion bar, the other end of said torsion bar is adapted to be rotated by a hydraulic actuator or the like by means of a one-way coupling, and a ratchet wheel is mounted on the reed shaft and is releasably engaged by a locking pawl to hold the reed shaft in position during the rotation of the other end of the torsion bar. When the reed shaft is held in position by the ratchet wheel and the ratchet pawl, the torsion bar is twisted and wound up, as it were, by means of the hydraulic actuator. When the locking pawl is then disengaged at the desired time, the spring force of the torsion bar is suddenly released to impart to the reed shaft a fast rotation resulting in a strong impact of the filling thread on the fell of the cloth. Whereas all known means for driving reed shafts comprise means for positively controlling the rotation of the reed shaft so that the angular positions after each beating-up are predetermined, the torsion bar in the system according to the invention exerts on the reed shaft a torque which does not ensure a predetermined end position of the reed shaft because the reed roller is braked by the fell of the cloth. This results in the strong impact of the filling thread. After the impact, the locking pawl reengages the ratchet wheel and the cycle can be repeated. The direct transmission of force and the coaxial arrangement of the torsion bar result in a relatively simple and compact, space-saving structure. Because the torsion bar can be wound up at any desired time between two reed movements, this winding can be performed when the machine does not require energy for other purposes so that the distribution ofthe energy requirement of the entire weaving machine can be improved so as to avoid shock loads. This will be the case particularly if, eg, the heddles are also hydraulically actuated because a smaller pressure accumulator for the hydraulic pressure fluid will be sufficient.

To enable a setting of the force with which the filling thread impinges, the angle of twist of the torsion bar may be changed. This may be accomplished, cg, by a change of the hydraulic pressure in the cylinder of the hydraulic actuator. In that the torsion bar will be twisted through such an angle that an equilibrium is obtained between the moment of resistance of the torsion and the piston force. The impact force of the filling thread can be adjusted in a particularly simple manner in accordance with the invention if the abutment for supporting the hydraulic actuator or the like on the machine frame is adjustable approximately in the direction of the axis of the cylinder. In such an arrangement, the angle of twist of the torsion bar as it is wound up is not changed but the torsion bar is always wound up to the same extent as a result of a constant hydraulic pressure. When the abutment for the piston drive has been adjusted in the direction of the cylinder axis, the effective stroke of the hydraulic actuator will be changed so that, upon a disengagement of the locking pawl from the ratchet wheel, the actuator can act on the torsion bar in the sense in which the latter rotates so that the force for driving the reed shaft is increased. The stroke through which the piston can move when the ratchet wheel has been released can be adjusted by a screw and will determine the impact force of the filling thread. Because the screw can be actuated at any time, even when the weaving machine is in operation, the appearance of the woven fabric can be changed in a desirable manner even during the operation of the weaving machine.

As a result ofthe hard impact of the filling thread, the dogs may rebound as they impinge on the fell and in that case no longer force the filling thread against the fell of the cloth. To avoid such rebound, the invention teaches to provide a reverse locking pawl which prevents a rotation of the ratchet wheel opposite to the sense in which a rotation is prevented by the locking pawl.

Particularly desirable means for disengaging the locking pawl from the ratchet wheel against the force of a h0lding-d0wn spring comprise 21 preferably hydraulically displaceable cam bar and at least one tappet which rests on the cam bar.

The ratchet wheel consists of two parts which have interengaging serrations between which a rubber part is disposed so that the ratchet wheel absorbs shock like a metal-clad rubber block. As a result, noise is damped and heavy vibrations in the machine are avoided. For the same reason, the locking pawl has in a known manner a shock-absorbing insert which protrudes over the engaging surface of the pawl. In a known arrangement (German Pat. No. 288,043) a locking pawl bears on a pivot pin by means of a rubber member but the metal pawl strikes on the metal ratchet wheel so that pawl fractures cannot be avoided.

In one embodiment of the invention, the ratchet wheel, the locking pawl and the reverse locking pawl are accommodated in the bearing housing for the reed shaft. This arrangement results in a further reduction of the overall length and in an improved protection from dust and damping of noise. Besides, the relatively highly loaded ratchet wheel is then disposed close to the shaft bearings so that the shaft is relieved.

Finally, in accordance with one feature of the invention, the one-way coupling is rotatably mounted on the end portion of the reed shaft and in a manner known per se is coupled by a tube to that end of the torsion bar which is remote from the reed shaft. In this way, the structure is further simplified because the otherwise existing need for special means for hearing the one-way coupling is eliminated.

An embodiment of the invention is shown diagrammatically and by way of example in the accompanying drawings, in which FIG. 1 is an axial sectional view taken through the reed shaft and showing a drive system according to the invention for intermittently rotating a reed roller,

FIG. 2 is a sectional view taken on line II-II of FIG. 1 through the one-way coupling,

FIG. 3 is a sectional view taken on line IIIIII of FIG. 1 through the ratchet wheel, which is corotationally connected to the reed shaft, and

FIG. 4 is a view taken on line IVI\ in FIG. 3 and showing the means for driving the locking pawl cooperating with the ratchet wheel.

An intermittently unidirectionally rotating reed roller l comprises a multiplicity olthin reed discs 2 which are aligned on a common reed shaft 3 and provided with dogs which engage the filling thread that has been inserted into the shed and beat up the thread against the fell of the cloth.

The means for intermittently unidirectionally driving the reed shaft 3 comprise a ratchet wheel 4 which is corotationally connected to the reed shaft and is locked against rotation in a direction opposite to that of rotation by a locking pawl 5. A torsion bar 6 is coaxial with the reed shaft 3 and has one end corotationally connected thereto while its other end is freely rotatably mounted by a stub shaft 7. That end of the torsion bar 6 which is mounted in the stub shaft 7 is corotationally connected to a tube 8 which by a rigid coupling 9 is corotationally connected to a ratchet wheel 10 of a oneway coupling which consists of the ratchet wheel 10 and a pawl 11. The pawl 11 is spring-urged against the ratchet wheel 10 and pivoted to a radial arm 12 which is freely rotatable about the reed shaft 3 and to which a piston rod 13 of a hydraulic actuator 14 is pivotally connected. The hydraulic actuator is mounted in an abutment 16 for rotation about a pivot 15, and the abutment 16 is adjustable by means ofa screw 17 along a guide 18 which is associated with the machine frame and which extends approximately parallel to the axis of the hydraulic actuator 14. It will be understood that the hydraulic actuator could be replaced by other suitable drive means, such as pneumatic actuators or the like.

If the actuator 14 is actuated so that the pawl 11 drives the ratchet wheel 10, the torsion bar 6 will be wound up by the tube 8 because the torsion bar is freely rotatably mounted at one end by means of the stub shaft 7 and at its other end is corotationally connected to the reed shaft 3 which is locked by the ratchet wheel 4 and the locking pawl 5. When the actuator 14 has performed its stroke, the locking pawl 5 can be disengaged. The torsion bar 6 is now held at its end opposite to the reed shaft 3 by the actuator 14 and the one-

way coupling

10, 11 and can untwist to rotate the reed As is shown in FIGS. 3 and 4, the locking pawl 5 is disengaged by two tappets 20 which are operated by a cam bar 19 and which, in response to a suitable displacement of the cam bar 19, lift the locking pawl 5 against the force of a spring 21, the initial stress of which is adjustable by means of an adjusting screw 22. The cam bar 19 is designed so that the locking pawl 5, when lifted by the tappets 20, can return to its locking position under the action of the spring 21 so as to lock the ratchet wheel 4 exactly in the position determined by the ratchet teeth 23. To avoid a rebound of the reed shaft after a strong impact of the filling thread, a reverse locking pawl 24 is provided, which prevents a reverse rotation of the ratchet wheel 4 and consists of a leaf spring which snaps in behind a stop face of the ratchet teeth. To reduce the shock which is due to the high acceleration of the reed shaft, the ratchet wheel 4 comprises two

parts

26 and 27, which have interengaging serrations, between which a member 25 having rubberlike elasticity is disposed. Besides, the locking pawl 5 has a shock-absorbing insert 28, which protrudes f m tbss a itt sw w The cam bar 19 is supported on two bearing rollers 29 and is driven by a hydraulic actuator 30 which is actuated in synchronism with the angular movements of the reed shaft. A particularly simple structure will be obtained if the ratchet wheel 4, the locking pawl Sand the reverse locking pawl 24 are accommodated in the bearing housing 31 for the reed shaft 3.

The angle of twist ofthe torsion bar 6 can be changed to vary the impact force of the filling thread. For this purpose, the hydraulic pressure in the actuator 14 may be varied. If the pressure of the hydraulic pressure fluid is increased, the torsion bar 6 will be more highly stressed so that the reed shaft 3 will be rotated by a stronger force when the locking pawl 5 has been disengaged. On the other hand, the impact force of the filling thread may be changed even when the hydraulic pressure fluid is always admitted under the same pressure. For this purpose, the abutment 16 for the actuator 14 is displaceable in the direction of the cylinder axis by the screw 17. Because the hydraulic fluid is always ad mitted under the same pressure, the torsion bar is always twisted to the same extent so that the same stroke of the piston is required to wind up the torsion bar. A gap remains between the abutment and the piston when the torsion bar has been wound up and, when the torsion bar unwinds, the hydraulic pressure in the cylinder acts on the piston to move the same through said gap so that an additional driving force is exerted on the reed shaft 3. The extent of this gap which exists at the time when the system for driving the reed shaft is released can be adjusted by means of the screw 17 so that the additional force exerted by the piston on the reed shaft and with it the impact force can be adjusted. This adjustment of the impact force exerted by the filling thread can be performed even during the operation of the machine and enables a desirable control of the appearance of the woven fabric even during the operation of the machine.

What is claimed is: l. A drive system for intermittently rotating a reed roller incorporated in a flat weaving machine, which system comprises l. a unidirectionally rotatably mounted reed shaft acutating means to the second end of said torsion rotationally connected to the reed roller, the reed bar for the unidirectional rotation thereof, roller including a multiplicity of reed discs proa. the actuating means holding the second torsion vided with dogs, bar end in the rotated position, 2. a torsion bar coaxial with the reed shaft and having 7. a ratchet wheel corotationally connected to the first and second ends, 10 reed shaft, a. the first end of the torsion bar being corotation- 8. a locking pawl movable into and out oflocking enally connected to one end of the reed shaft, gagement with the ratchet wheel, and 3. actuating means connected to the second end of 9. means for holding the locking pawl in locking enthe torsion bar and operable to rotate the second gagement with the ratchet wheel to hold the reed end of the torsion bar in the direction of rotation shaft against rotation during the rotation of the secof the reed shaft, ond end of said torsion bar by the actuating means 4. a one-way coupling operatively connecting the acand thus to twist the torsion bar, and for moving tuating means to the second end of said torsion bar the pawl out of locking position with the ratchet for the unidirectional rotation thereof, 7 wheel to permit the twisted torsion bar to rotate the a. the actuating means holding the second torsion reed shaft unidirectionally. 7

bar end in the rotated Position, 5. A drive system as set forth in claim 4, in which a ratchet Wheel corotatlonally Connected to the said abutment is slidably guidedin said frame approxreed Shaft imately in the direction of the axis of said cylinder, 6. a locking pawl movable into and out of locking enand gagement with the ratchet wheel, and

7. means for holding the locking pawl in locking engagement with the ratchet wheel to hold the reed shaft against rotation during the rotation of the second end of said torsion bar by the actuating means and thus to twist the torsion bar, and for moving the pawl out of locking position with the ratchet wheel to permit the twisted torsion bar to rotate the reed shaft unidirectionally.

4. actuating means connected to the second end of the torsion bar and operable to rotate the second end of the torsion bar in the direction of rotation of the reed shaft,

5. an abutment which supports the actuating means on the frame,

a. the actuating means including a cylinder and a piston movable therein and connected to the sec- I ond end of the torsion bar, and

a screw is provided which is operable to move said abutment in said direction. 6. A drive system for intermittently rotating a reed roller incorporated in a flat weaving machine, which system comprises 1. a unidirectionally rotatably mounted reed shaft corotationally connected to the reed roller, the reed roller including a multiplicity of reed discs provided with dogs,

A drive system as Set forth claim l.comprising 2. a torsion bar coaxial with the reed shaft and having a reverse locking pawl movable into locking engage first and second ends [2611i \fv th hthedratcl'iet wf i Prevent a rotanon a. the first end of the torsion bar being corotationt ereo t e lrecuon O m ally connected to one end of the reed shaft,

A dnve System as Set fQrth m clzilm P Whlch the 3. actuating means connected to the second end of means for 9 the,locklng pawl m engage' 40 the torsion bar and operable to rotate the second mem Compnses 'flctmg on the lockmg pawl end of the torsion bar in the direction of rotation and further comprising lifting means operable to move of the reed Shaft the locking pawl out of engagement with. h ratchet 4. a one-way coupling operatively connecting the acwheel the force of the Spring the llftmg means tuating means to the second end of said torsion bar including a displaceable cam bar and at least one tapfor the unidirectional rotation thereof pet resting on the cam bar and connected to the locking u the actuating means holding the Second torsion pawl bar end in the rotated position,

Adm/e fl" m romtlng re ed 5. a ratchet wheel coi'otatiomilly connected to the roller incorporated in a flat weaving machine, which w reed Shah system f n i i a. the ratchet wheel comprising two parts having l.a unidirectionally rotatably mounted reed shatt co imemngaging serrations and a rubber pan rotationally connected to the reed roller, the reed posed between [he serrations fi "l multlphclty reed dlscs 6. a'locking pawl movable into and out oflocking en- V'ded dogs 55, gagement with the ratchet wheel, and 2. a torsion bar coaxial with the reed shaft and having 7' means for holding the locking pawl in locking first d ends I gagement with the ratchet wheel to hold the reed [he and of f" bemg comtdnon shaft against rotation during the rotation ofthe sec- Y Connected to one mid of the reed Shaft ond end of said torsion bar by the actuating means a frame 0 and thus to twist the torsion bar, and for moving the pawl out of locking position with the ratchet wheel to permit the twisted torsion bar to rotate the reed shaft unidirectionally.

7. A drive system for intermittently rotating a reed roller incorporated in a flat weaving machine, which system comprises 1. a unidirectionally rotatably mounted reed shaft corotationally connected to the reed roller, the reed roller including a multiplicity of reed discs provided with dogs,

2. a torsion bar coaxial with the reed shaft and having first and second ends,

a. the first end of the torsion bar being corotationally connected to one end of the reed shaft,

3. actuating means connected to the second end of the torsion bar and operable to rotate the second end of the torsion bar in the direction of rotation of the reed shaft,

4. a oneway coupling operatively connecting the actuating means to the second end of said torsion bar for the unidirectional rotation thereof,

a. the actuating means holding the second torsion bar end in the rotated position,

5. a ratchet wheel corotationally connected to the reed shaft,

6. a locking pawl movable into and out of locking engagement with the ratchet wheel,

a. the locking pawl having an engaging surface for contacting the ratchet wheel in locking engagement therewith, and

b. the locking pawl comprising a shock-absorbing insert protruding from the engaging surface, and

8. A drive system for intermittently rotating a reed roller incorporated in a flat weaving machine, which system comprises l. a unidirectionally rotatably mounted reed shaft corotationally connected to the reed roller, the reed roller including a multiplicity of reed discs provided with dogs,

2. a torsion bar coaxial with the reed shaft and having first and second ends,

3. actuating means connected to the second end of the torsion bar and operable to rotate the second end of the torsion bar and operable to rotate the second end of the torsion bar in the direction of rotation of the reed shaft,

a. the one-way coupling being rotatably mounted on the reed shaft at the one end thereof,

5. a tube corotationally connecting the one side of the oneway coupling to the second end of the torsion bar,

6. a ratchet wheel corotationally connected to the reed shaft,

7. a locking pawl movable into and out of locking engagement with the ratchet wheel, and

8. means for holding the locking pawl in locking engagement with the ratchet wheel to hold the reed shaft against rotation during the rotation of the second end of said torsion bar by the actuating means and thus to twist the torsion bar, and for moving the pawl out of locking position with the ratchet wheel to permit the twisted torsion bar to rotate the reed shaft unidirectionally.

Claims

1. A drive system for intermittently rotating a reed roller incorporated in a flat weaving machine, which system comprises 1. a unidirectionally rotatably mounted reed shaft corotationally connected to the reed roller, the reed roller including a multiplicity of reed discs provided with dogs, 2. a torsion bar coaxial with the reed shaft and having first and second ends, a. the first end of the torsion bar being corotationally connected to one end of the reed shaft, 3. actuating means connected to the second end of the torsion bar and operable to rotate the second end of the torsion bar in the direction of rotation of the reed shaft, 4. a one-way coupling operatively connecting the actuating means to the second end of said torsion bar for the unidirectional rotation thereof, a. the actuating means holding the second torsion bar end in the rotated position, 5. a ratchet wheel corotationally connected to the reed shaft, 6. a locking pawl movable into and out of locking engagement with the ratchet wheel, and 7. means for holding the locking pawl in locking engagement with the ratchet wheel to hold the reed shaft against rotation during the rotation of the second end of said torsion bar by the actuating means and thus to twist the torsion bar, and for moving the pawl out of locking position with the ratchet wheel to permit the twisted torsion bar to rotate the reed shaft unidirectionally.

2. a torsion bar coaxial with the reed shaft and having first and second ends, a. the first end of the torsion bar being corotationally connected to one end of the reed shaft,

2. A drive system as set forth in claim 1, comprising a reverse locking pawl movable into locking engagement with the ratchet wheel to prevent a rotation thereof in the direction of rotation.

3. a frame,

3. A drive system as set forth in claim 1, in which the means for holding the locking pawl in locking engagement comprises a spring acting on the locking pawl, and further comprising lifting means operable to move the locking pawl out of engagement with the ratchet wheel against the force of the spring, the lifting means including a displaceable cam bar and at least one tappet resting on the cam bar and connected to the locking pawl.

4. a one-way coupling operatively connecting the actuating means to the second end of said torsion bar for the unidirectional rotation thereof, a. the actuating means holding the second torsion bar end in the rotated position,

4. a one-way coupling operatively connecting the actuating means to the second end of said torsion bar for the unidirectional rotation thereof, a. the one-way coupling being rotatably mounted on the reed shaft at the one end thereof,

4. A drive system for intermittently rotating a reed roller incorporated in a flat weaving machine, which system comprises

5. an abutment which supports the actuating means on the frame, a. the actuating means including a cylinder and a piston movable therein and connected to the second end of the torsion bar, and b. the abutment being adjustable relative to the frame approximately in the direction of the axis of the cylinder,

5. a ratchet wheel corotationally connected to the reed shaft, a. the ratchet wheel comprising two parts having interengaging serrations and a rubber part disposed between the serrations,

5. A drive system as set forth in claim 4, in which said abutment is slidably guided in said frame approximately in the direction of the axis of said cylinder, and a screw is provided which is operable to move said abutment in said direction.

5. a ratchet wheel corotationally connected to the reed shaft,

6. a locking pawl movable into and out of locking engagement with the ratchet wheel, and

6. a ratchet wheel corotationally connected to the reed shaft,

6. a locking pawl movable into and out of locking engagement with the ratchet wheel, a. the locking pawl having an engaging surface for contacting the ratchet wheel in locking engagement therewith, and b. the locking pawl comprising a shock-absorbing insert protruding from the engaging surface, and

6. A drive system for intermittently rotating a reed roller incorporated in a flat weaving machine, which system comprises

6. a one-way coupling operatively connecting the acutating means to the second end of said torsion bar for the unidirectional rotation thereof, a. the actuating means holding the second torsion bar end in the rotated position,

7. a ratchet wheel corotationally connected to the reed shaft,

7. A drive system for intermittently rotating a reed roller incorporated in a flat weaving machine, which system comprises

8. A drive system for intermittently rotating a reed roller incorporated in a flat weaving machine, which system comprises

8. a locking pawl movable into and out of locking engagement with the ratchet wheel, and

9. means for holding the locking pawl in locking engagement with the ratchet wheel to hold the reed shaft against rotation during the rotation of the second end of said torsion bar by the actuating means and thus to twist the torsion bar, and for moving the pawl out of locking position with the ratchet wheel to permit the twisted torsion bar to rotate the reed shaft unidirectionally.