US2426971A

US2426971A - Loom and hydraulic check therefor

Info

Publication number: US2426971A
Application number: US508086A
Authority: US
Inventors: Otto A Kottemann
Original assignee: WILLIAM D DODENHOFF
Current assignee: WILLIAM D DODENHOFF
Priority date: 1943-10-27
Filing date: 1943-10-27
Publication date: 1947-09-02
Anticipated expiration: 1964-09-02

Description

Sept. 2, 1947. 0.1 KOTTEMANN 2,426,971

LOOM AND HYDRAULIC CHECK THEREFOR Filed Oct. 27, 1943 5 Sheets-Sheet 1 I l 0 Y a; X I lvwsmog Sept. 2, 1947. v 0. A. KOTTEMANN 2,426,971

LOOM AND HYDRAULIC CHECK THEREFOR Filed cm. 27. 1943 5 Sheets-Shet2 I 68 69 126127 30 I 5% I INVENTOIL may Se t. 2, 194?. o. A. KOTTEMANN LOOM AND HYDRAULIC Ji-IECK THEREFOR Filed Oct. 27, 1943 a 5 Sheets-Sheet 3 0. A. KOTTEMANN LOOM AND HYDRAULIC CHECK THEREFOR Sept; 2, 1947.

Filed Oct. 27, 1945 s Sheets-Sheet 5 UNI STATES PATEN OFFICE r 2,426,971 1 LOOM AND HYDRAULIC CHECK 'rncacron Otto A. Kottemann, (K'leenville, S. 0., assignor to William D. Dodo off, Greenville, S. 0.

Application October 2'1, 1943, Serial No. 508,086 1s Claims. (01. 139-161) This invention relates to a device for reducing straps. In attempting to assist the check straps, the velocity of a body moving horizontally at a looms are provided with rather powerful binder high rate of sp d. long a prescribed path, and springs in the shuttle box to laterally frictionally f r ng h y to a dead s p precisely retard the shuttle; the tension on these springs at a predetermined point along said path, without 5 is much greater than what is needed merely for rebound. a snug holding of the shuttle. But these springs More specifically, the present invention relates absorb power on the thrower projection of the to a device for checking the oscillatory motion of shuttle, and prematurely retard the shuttle a the picker stick at each side of the lay of a loom, enters the shuttle box, causing a loss in speed of to cause the picker sticks at the opposite sides rethe loom. They ave not cause t heck straps spectively of the loom to alternately effect rapid to operate satisfactorily.

deceleration and dead stopping of the loom shut- It is therefore an object of the invention to protle at each end of the path orthe shuttle, at avide improved means to obviate the difficulties predetermined point in the shuttle path, accumentioned. It is another object to provide an imrately and without rebounding from the stopping proved check capable of satisfactorily functioning point, whereby the filling yarn laid in the open without the use of the binder spring and utilizing warp shed in the loom by the shuttle will be only a light spring for snugly positioning the maintained uniformly under predetermined tenshuttle.

sion at all times, thus avoiding the formation of Because check straps are mounted on one side,

marks in the fabric being woven and which are a twisting tendency is imparted to the picker stick primarily formed normally by the shuttle rewhich results in excessive strains and eventual bounding from its stopping position in its path at misalinement of parts.

' the end of its travel which causes slack to develop It is therefore another object of the invention in the filling ya1'n to provide improved means such that the impact In the case of looms employing automatic bobof the picker stick is squarely received and abbin replenishing apparatus, for replacing empty sorbed. bobbins in the shuttle with full bobbins of the EL After the picker stick has projected or thrown ing yarn, the devic of the present invention, in the shuttle, it is desirable to properly cushion it stopping the shuttle dead at a predetermined and to quickly bring it to rest for return by spring point in the shuttle path at one end of the loom, action to shuttle receiving position. This will afavoids the possibility of fa'lure of the bobbin refeet the speed of the loom and the shock and viplenishing mechanism. A typical loom operates bration therein. The check straps and other at 180 picks per minute, in other words, there are leather cushioning devices have not been satis- 180 throws of the shuttle per minute, The travel factory.

for each throw may be about '70 inches. If it be It is therefore another object of the invention considered that the shuttle is at rest in a shuttle to provide an improved check that is double actbox approximately three-fourths of the time, it ing in that it will precisely and with split second will be perceived at the actual mean velocit of timing arrest apicker stick both on its inward or the shuttle is about 4200 feet per minute. Travelpower stroke and on its outward travel under the ing at high speed, the shuttle must be brought to 40 power of the shuttle, whereby the efficiency and complete rest within a distance of 3 or 4 inches. life of the loom are substantially increased, and This distance cannot be increased without loss in frequency recurring shutdowns for realinement the speed of the loom. The extremely high deand adjustment of parts of the loom avoided.

celeration involved has posed a problem which has Another object, of the invention is the provision not been solved heretofore. of improved means whereby thechecking action It has been proposed to use pneumatic check may be adjusted while the loom is in operation.

a devices, but these are unsatisfactory. Today the Another object of the invention is to furnish dinary h k strap is universally in. use, alimproved structure for a different precise checkthough the complaints in regard thereto are wideing of the inward and outward movements of the spread. Loom deterioration due to shock and vipicker St ckbration is rapid, and the slightest damage in the Another object of the invention is to provide a cloth is a basis for rejection especially under device having improved means such that a great- United States government specifications. Looms er range of checking action for the outward as are operated at speeds below those for which they compared with the, inward throw can be adjustwere built, and the blame is placed on the check ably obtained. 7

' 3 4 Another object or the invention is to furnish moved showing the linkage arbitrarily extended improved means adjustable for diil'erent ranges to disclose certain details thereof. of movement 01 the picker sticks of diiferent Figure 6 is a bottom plan view of an adjusting v looms, for checking the picker sticks at the oppomeans of the device in detached position, showing site ends of their travel. a diilerent adjustment for a lesser checking range Another object oi? the invention is the provion the inward than on the outward movement sion of improved means for adjusting the checkof the picker stick.

mg action according t th varying sizes and gure 7 is a sectional view taken on the line weights of the shuttles oi difierent looms. i! of Figure 8 with certain parts removed and Another object of the invention is to provide with the device in an arbitrary central position improved checking means which shall not retard fOr clarity in the drawings.

the picker stick on itspower stroke while it is Figure 8 is a sectional view taken, e r l on actively engaged in projecting the shuttle. line 88 of Figure 7. ,Another object of the invention is to construct Figure 9 is a sectional view taken on line 9 a device for checking a picker stick at both ends of Figure 7.

of its travel, with improvedmeans for a lost mo- Figure 10 is a sectional view taken on line ilitiori engagement to reduce travel and wear of up of Fi ure 4, with parts omitted crating parts, increase compactness, and avoid Figure 11 is a view of the left end of Figur 10 imposing an added load or weight on the picker sure 12 a full 8129 view of a check valve stick while it is projecting the shuttle. device shown in Figures 7 and 10, looking at the Another object of the invention is to provide inner end e an improved highly compact unit, capable of e- Figure 13 is a view of the inside face of an spending to a substantial angular movement of a d l re P u f r the cylinder of the hydrauthe picker stick and hence adapted to be positioned relatively high up on the stick to avoid Figure is a full Size m n y sectional deflection of the latter. View particularly of the bleeder valve of the hy- Another object of the invention is to furnish a afllie device as set forth capable of being positioned in res 15 and 16 are similar views showing the loom so that adjoining 100 can be placed .30 Figs. 1 to inclusive, constitute a series of virtuallyin Contact wit each other, diagrams illustrating the actions of the pistons Another object of the invention is to construct and other associated Parts of the device throughan improved check which can be placed reversiout one emplete Cycle of wns thereof.

bly atithe right or left of a 100m The advantages of the invention as here out- Another object is to provide an improved circuare best realized When l of its features latory system for an hydraulic check and instrumentalities are combined in one an Another oblect is to utilize hydraulic action for the same structufei but, useful devices y e cushioning engagement at the ends of a lost moproduced less n the l tion throw. t W111 be obv ous to those skilled in the art Another object is to obtain liquid rotation of a 40 to which F invention eppertains. th the same piston for even wear. 1 l

Another object is to cushion a picker stick by strucuonsaccompanying d a in thereconjoint action of a bleeder valve and a piston is submltted mere1y s w ng the pre- C1osure ferred exemplification of the invention.

other Objects and advantages of the invention Generally described, the invention is indicated will become apparent as the specification in aloom wherein the picker stick is checked by Ceeds causing it to actuate a positive pressure hydrau- With the aforesaid objects in View, the invem lic brake that drives a liquid through an orifice,

tion consists in the novel combinations and arthe chfeckmg bringing the picker Stick to rest at rangements of parts hereinafter described in a precise point the Orifiee may remain drawing, wherein like parts are designated by ree of rebwnd the Sheet 8 P nt at the same reference characters throughout the Whlch the picker stck comes to Test easily Severa] Views Justed by varying the flow area ofthe orifice, but In t drawing: once this adjustment has been made, no devia- Figure 1 1s a fragmentar View in front eieva, tion in the position of rest will occur, except for tion with parts in section, drawn approximately causes residing in the condition of wear of the to one quarter scale, showing a loom embodying 100m itself- More Specifically, the r t on of the the invention, with dlflerent positions of the picknovel checking device to the P r Stick s eer stick indicated in g dash lines lieved to be such that the liquid pressure is in- Figure 2 i a top plan i t part removed dicated by a. curve whose slope is substantially and in section, drawn t n. half scale and constant from maximum to zero pressure, the showing a device according to the invention with fame! Occurring when Checking begins, nd the the picker tick b ht t t t t end of its latter occurring when the picker stick comes to utward th w, rest. This curve may vary somewhat as will apgure 3 is a similar view but showing the depear hereinafter, but it difiers radically from vice with the picker stick brought to rest at the curves for Springs and Pneumatic ces eend of its inward throw. cause a liquid is substantially incompressible,

Figure 4 is a View in elevation with parts re and because the energy of the h le is c n moved showing a position of the device intermesinned in fluid friction in the Sald Orifice T1118 m of those f F gures 2 and 3 and th th device may be double acting to check the picker picker stick angularly moved with the lay of the stick at b01111 end P 1 1 of its P h f tr vel- 1oom To prevent the device from otherwise impeding Figure 5 is a view in elevation with parts rethe picker stick, a lost motion engagement is prorided between the picker stick and the device, such engagement being adjustable for varying iengths of travel for different looms. The double acting lost motion feature is of value in restormg the device to its initial position, even if the picker stick is checked at only one end of its path of travel. The speed of operation of the loom can be increased and the binder spring omitted.

Referring in detail to the drawings, 20 denotes a device embodying the invention and comprising means for hurling and/or receiving a projectilelike element and for rapidly absorbing the momentum involved, without rebound of the element. The device 20 is best exemplified in a loom having a. base 2|, having a frame 2m, in which is mounted for oscillation a conventional rocker shaft 22, said rocker shaft having the lower end of a loom sword 23 fixedly secured thereon. This loom sword extends upwardly and is adapted to support a lay 24, which in turn supports a shuttle box 25.

Rocker shaft 22 also has fixedly secured thereto a base member 26, upon which a picker stick shoe 21 is adapted to rock back and forth. The shoe 21 supports an upwardly extending picker stick 28, which passes through a slot 29 in the lay 24. The upper projecting end of the picker stick 28 is disposed within the shuttle box 25, and has a picker 30 secured thereon, said picker being adapted to receive and expel a conventional loom shuttle 3| during the normal operation of the loom.

In order for the picker stick 28 to be moved in clockwise manner about the shoe 21, when the shuttle is to be expelled from the shuttle box, it is necessary to provide some suitable means such as a conventional lug strap 32. One end of this lug strap encircles the intermediate portion of the picker stick and is held in position by means of a notched hold-up strap 33. The other end of this lug strap is connected as at 34 to a lever 35, said lever being pivoted at 36 to the loom frame 2la. A conventional means, not shown, is employed for oscillating the lever 35 back and forth about pivot 36 to thereby impart the necessary sudden thrust upon the picker stick and cause the shuttle 3| to be powerfully expelled from the shuttle box 25.

Disposed beneath the base member 26 is a torsion spring I31 acting on a strap I38 to cause counterclockwise movement of the picker stick to the position shown in full lines in Fig. 1.

When the 100m is in operation, the members 23 to 30 inclusive are adapted to rock back and forth toward and away from'the observer in Fig. l, about-the rocker shaft 22 as an axis. At the same time, the picker stick 28 and its picker 30 oscillate back and forth in a plane disposed substantially at right angles to the plane of oscillation of the members 23 to 30. In each loom there is an opposite-hand structure to that shown in Fig. 1 disposed at the opposite end of the loom, to thus cause reciprocation of the shuttle between the ends of the loom.

- The conventional traverse of the picker stick is indicated in dot dash lines, 28a denoting the outer, and 2% the inner position. Normally, the picker stick receives the impact of the shuttle on the picker 30 at some intermediate position to which the picker stick is moved by the spring i-31 in readiness to receive the impact of the shuttle. According to the present invention, and speaking in more or less general terms this intermediate or neutral position N is predetermined to that shown in full lines, being closer to the position 280. than heretofore. Accordingly, the checking movement at the picker 30 is about 3 inches, as indicated at A. A checking action also occurs on the inward power stroke of the shuttle beginning at the position indicated at 28c; hence the checking movement is indicated at B. The checking movements at A and B may be equal, but I have discovered that a higher speed is obtainable with satisfactory results by making the checking movement at B about half that at A; at the same time the checking movement at A has been substantially reduced for the same reasons. Preceding each of the checking paths A and B, there is a section of the path along which the picker stick is preferably free of the hydraulic check both on the outward and inward strokes of the stick. On the outward stroke this free section includes thesection B plus a section C, which lies intermediate the checking sections Aand B, and onthe inward stroke the free section includes the section C plus the checking section A, as will be apparent hereinafter. Accordingly, the full power and maximum velocityof the system is available with the picker stick traveling the path A to position 28a to bring the shuttle to rest without rebound. Although the picker stick receives the impact of the shuttle at position N, its power stroke may be from the position 28a. and when the picker stick reaches the position 28c, or slightly before, the shuttle has left the picker stick, and checking of the picker stick occurs along path B to avoid vibration and shock in the loom and to bring it rapidly to rest, for quick return to position N. A full detailed description of one complete cycle of operation of the picker stick, etc., will be given hereinafter.

Referring now to the checking device, 31'denotes a hydraulic unit embodying the invention. A hydraulic means is employed because it affords a pressure curve that is directly proportional to the diminishing momentum of the mass that is to be checked, which curve is believed to be substantially a straight line. This is in direct contrast with the haphazard action of a check strap, and with the operation of pneumatic devices wherein the fluid pressure first increases while the momentum decreases, after which the 'fiuid pressure must gradually taper off on a long path if it is not to cause rebound of the shuttle or a premature or incorrect projection of the shuttle by varying the position at which the impact is imparted tothe shuttle by the picker stick. Such gradual tapering off of pneumatic pressure is not feasible because it would require a longer loom and would result in a loss of speed in loom operation. On the other hand, a sharp cut off is impractical for the reasons stated, and because the results would be erratic, and automatic bobbin changing which requires precise positioning of the shuttle in its outer position of rest could not be obtained. These difficulties are avoided by hydraulically checking the momentum of the rapidly moving mass that includes the shuttle and at least part of the weight of the picker stick. When the latter attains the outer position of rest at 23a, the liquid pressure is zero and the hydraulic device 31 is relieved substantially of all stresses. Yet the precise position for 28a may be adjusted with nicety, as by adjusting a restrictive liquid outlet which may be only about of an inch in diameter with the total liquid displaced for the checking at A measuring only about two to ten teaspoonfuls. And all this is effected despite the substantial mass of a shuttle that may be 15 inches in length or longer and, in

. 7 g which the deceleration for bringing the shuttle to rest at its high speed may be terrific, as herein-before indicated.

The hydraulic unit 31 may include a casing 38 comprising a pair of identical casing sections 39 having arcuate flanges 40 extending into straight flanges 41, as shown in Fig. 8. Interrupting the flanges are a pair of identical

alined hubs

42, 48, each of which is split along the plane of the flanges. Engageable with the

hubs

42, 43 are the

respective fittings

44, 45, the threads of which may have a slight taper for powerfully drawing or clamping the casing sections together so that a fluid tight engagement is obtained between the sections by placing a cement on the meeting faces of the flanges 40, 4|. Alining pins (not shown) may be used between the casing sections to facilitate the engagement mentioned. Bolts 46 passing through holes 41 in the straight flanges may be used to clamp the casing 38 to a standard 48 fixedly connected to or forming a part of the loom frame, or directly connected to the building floor, in such a manner to avoid vibrations. Bolts or screws may also be provided for clamping together the flanges 46.

Formed in the casing sections are the alined cylinders 49,.secured to their respective casings by radial webs 50, see Figs. 7 to 11, thus forming passages 52 between these cylinders and the walls of the casing 38. Each cylinder terminates in spaced relation to the outer ends of the easing, and these cylinders are also spaced from each other. A double acting one-piece piston means 53 may comprise identical

hollow pistons

54, 55 between which is formed an annular recess providing a central connecting neck 55a. For reciprocating the piston means there is provided a shaft 56 and a stub shaft 51 interchangeably journaled in the

hubs

42, 43. Integrally formed on this shaft is a crank portion 58 having a central cut out at 59, see Fig. 8, sumcient to clear the piston means upon oscillation of the crank portion. Slidingly engaged in the recess of the piston means at opposite sides of the neck 5511 are the drivers 60, see Fig. '1, and as these are desirably flat to snugly fit the said recess, they are journaled by means of stub shafts 5| in the arms of the crank portion 58, so that the axes of the stub shafts lie in a plane with the axis of the piston means. To allow for clearance for the crank portion, the cylinders 49 are spaced apart sufliciently and the casing sections 39 are formed with tapered oifsets 62, as clearly shown in Fig. 9, to conform to the oscillation of the crank portion. These offsets may be continued at B3 to afford clearance for-the

shafts

56, 51. To receive the shaft 56, the cap 44 is formed with a central opening. At its upper end portion, the shaft 56 is provided with an undercut threaded portion 64 and with flats at 65, non rotatably receiving a hub 66 of an actuator member 61 that serves to oscillate the shaft. This member is retained by a perforated threaded washer 68 and a nut 69 both engaged with the threaded part 64 of the shaft.

Closing the outer ends of the cylinders 49 are the removable identical check valve units 10, see Figs. 7, l0 and 12. Each unit comprises a circular casing 1| having a lip 12 for centering it in its cylinder 49 and having an annular flange 13 bearing against the outer end of the cylinder in precision contact therewith to afford a liquid tight seal. Each unit is clamped tightly in such sealing engagement by a plug 14, see Fig. 13-, having an interrupted circular flange 15 on its inner face to abut the unit 10, without interfering with the operation of the check valve unit. The latter may have an inlet opening 15 normally closed by a ball valve 11 actuated by an expansion coil spring 18 housed within the casing 11. That portion of said casing 1| which projects into the cylinder 49 is perforated or foraminous as at 19, and is sumciently small in diameter to be received within the open end of the confronting piston, as shown at the-left in Fig. 7. Sufiicient clearance is provided between the easing ll and the side wall of said piston for a free flow of liquid therebetween. inlet 16 of the check valve through the interrupted flange 15 with the passages 52 that lie between the casing 38 and its cylinders 49. Upon retraction of a piston, the check valve is opened by suction to admit liquid into its cylinder.

At 80 are restrictive by-pass or bleeder outlets for the difierent cylinders 49, shown in Figs. 7, 9, 10, 11 and 14. These outlets may be identical in size for reversibility of the device 31 for interchangeable use at either end of the loom. In a loom of the size and speed hereinbefore mentioned, each of these outlets may be about of an inch in diameter, and being reduced to about of opacity by needle valves hereinafter described, assuming that the liquid employed is a good quality of lubricating oil, such as is adapted to properly lubricate the moving parts in the casing 38, at the speed at which they operate. Incidentally, it may be mentioned that bearings such as those for the driver stub shafts 6| of the crank mechanism are perforated to assure proper lubrication. It may now be mentioned that copper or brass plugs 19a may carry permanent magnets 19b communicating with the liquid for abstracting minute particles of metal therefrom. Preferably the outlets 80 are placed at an acute angle to the horizontal, but this is merely a matter of convenience. These outlets 80 are shown in dot dash lines in Fig. 7. It may be desirable, however, that these outlets be positioned below the top portions of the cylinders so as not to be affected by any air that might be present. Later, it will be clear that the casing 38 may be so filled with liquid as to obviate the presence of air.

Formed in the webs 50 are short passages 8| which communicate the outlets 80 through the interrupted flange 15 of adjacent plugs 14 with the passages 52 that lie between the webs 50, 5|. It is desirable to provide for adjustment of the outlet openings 80 and hence

devices

82, 83 are employed. The device 82 is clearly shown in Fig. 14 and it is used to adjust the liquid resistance to absorb the momentum of the shuttle along the path A. The device 83 may be a simple plug having a tapered pin or valve 84 alined with its outlet opening 80 for adjusting the liquid resistance and cushioning action for the picker stick at the end of its inward stroke along the path l3. The device 82 may be adjusted as the condition of the loom requires. Device 83 need be iven only one initial adjustment. The adjustments of both devices may take care of numerous conditions including the viscosity of the oil, the weight and speed of the shuttle or picker stick, the range of checking action for these elements at A and B, and various other factors. These

devices

82, 83 are interchangeable on the casing 38 according as the device 31 is used at one or an opposite end of the loom.

5 More particularly described, the device 82 com- 38 to directly communicate prises a housing member 85 having a central bore which is constricted at 88 and threaded at 81, this bore leading into a chamber 88 that is externally threaded at 89. At its inner end, the housing member 85 is provided with an undercut threaded portion 98 whereby the housing member can be screwed into an opening in the casing with the adjacent passage 8'I. A needle valve 9| alined withv the cooperating valve opening 88 is mounted on a stem 92 that snugly slidingly closes the bore 88.

At 93 the'stem is enlarged and engaged with the threaded bore 81, and at its outer end the stem has a turning head such as a pinion 94 in the chamber 88. For remote control, a flexible shaft '95 shown in Fig. 1, may be connected to the housing at the thread 89, in engagement with the head 94, this shaft leading to a head 98 which may be mounted on a stationary frame portion 91. For turning the flexible shaft, a removable key 98 may be provided for 83 is secured in the identical manner of the device 82 and both operate in the same manner.

In order to permit a desired amount of free travel of the piston means 53, with its

pistons

54, 55, before the

bleeder devices

82, 83 become effective, it is necessary to afford openings for the rapid flow of liquid in the cylinders 49 until the capacity of the cylinders has been reduced to a predetermined volume. Such openings may be provided in the pistons themselves, subject to cut off by the cylinders when the pistons have penetrated the respective cylinders to a predetermined degree. In the instant case, these openings are shaped so that the said flow of the liquid may cause rotation of the pistons by repeated reciprocations thereof, whereby wear on the pistons in the cylinder and at their region of en- 10 the instant of initial movement of the piston means due. to the yielding action of the springs as the valves open. In the device I82, the spring must be sufliclently powerful to sustain the maxithe head 96. The device 7 mum liquid pressure on the valve, whereas in the device I 81 that maximum pressure is exerted on the positive abutmentor set screw I I2. Hence the range of opening movement of the valve I84 may be greater than that of the valve I89 to afford more yield during maximum'shock. On the other hand, If it be assumed that the spring; H8 is weaker than that at I85, the valve- I84 will tend to close more rapidly and afford an increased follow-up cushioning action as com--' pared with the valve I89, and hence bring the picker stick .more rapidly to rest as the momentum of the shuttle is reduced. In connection with these observations, it is to be noted that each opening 88 may be constructed like the socalled perfect orifice so that the coefficient of friction in-such opening may be constant; although the friction at the edges of these openings is not severe because the true area of discharge is determined by the needlevalve.

In each of the bleeder devices, the openings 88 may be about of an inch in diameter, and in each case the capacity thereof is reduced to about one third by the needle valves. This applie to the open positions of the valves I84 and I89. For the device 83 the reduction in area may be much less.

gagement with the crank shaft is equalized and rendered uniform. More particularly, these openings are shown in Fig. '7 at 99, I88, the piston 54 having a plurality of diametrically opposed elongated slot openings 99 sloped to conform to a right hand thread, and the openings I88 in the piston 55 being sloped to conform to a left hand thread. It will now be seen that an advance of the piston 58 into its cylinder creates a clockwise torque and an advance of piston 55 into its cylinder causes a torque in the same direction, so that there is a relatively constant tendency for rotation of the piston means 53.

Modifications of the device 82 are shown in Figs. 15 and 16. g In the former the device I82 comprises a casing I83 for a needle valve I84 which is like that at 9| except that it is normally urged to closing position by an expansion coil spring I85 which is adjustably tensioned by a head I88 like that at 94 but having threaded engagement with the casing I83.

The device I81 comprises a casing I88 having a needle valve I89 actuated to normally closed position by an expansion coil spring II8 whose tension is adjustable by a head III like that at I88. Carried by said head is an axial set screw I I2 which is snugly threadedly secured to the head for movement therewith. The relation between the headand the set screw may be adjusted so that the set screw may afford a positive step for opening movement of the valve I89.

The devices I82 and I81 by closing the ports 88, prevent any creeping flow of liquid such as may be caused by mere frictional forces in the mechanism hereinafter described which engages the piston means with the picker stick. Moreover, there is a small increase in cushioning action at The mechanism whereby the rocker shaft 58 is engaged with the picker stick 28, as in Figs. 1 to 6 inclusive, will now be described. Rigidly secured to the picker stick as by shackle bolts H3, is a plate I I4 having an ear I I5 rigidly carrying a stud or stub shaft II8 to which is afiixed the ball-like portion III of a ball and socket joint II8 which may have a capacity for rather limited universal movement. Rigidly connected to the ball and socket joint, or the casing thereof, is a pin II9 on which there may be secured a hub I28 forming an end of an L shaped lever I2I. The latter may include an arm I22 adapted to be alongside of the picker stick, and an arm I23 extending back of an edge of the picker stick, at which it carries a hinge structure I24 affordingpivotal action about axes that are at right angles to each other indicated by the bolts or screws I25, I28, and serving to connect a bent or curved lever I'2I to the lever I2I. The opposite end of the lever I2I is freely journaled at I28 on the hub of the actuator plate 81, as shown in Fig. 8. This plate, which is more particularly shown in Fig. 6, is a sector of a circle and is provided on its underside with arcuate members I29 carrying individual teeth I38. For angular adjustment of the stops, the members I29 have arcuate slots 7 I3I through which-extend bolts I32 for clamping to be reversed for use at either end of the loom.

Such reversal is accomplished by disengaging the lever I21 from the shaft and turning the linkage upside down so that the top lug I33 at the I left of a loom becomes the bottom lug I33 at the right of the loom, and vice versa, the casing and sector 81 being always in the upright position shown.

It will be noted that the lever I21 closely overrides the sector 61, and that the levers I2I and I21 lie in the same horizontal plane as clearly shown in Fig. 5. Hence the path of the teeth I30 and of the lug I33 is clear. The extreme positions of the sector 81 are shown in Figs. 2 and 3, the former corresponding to the picker stick position at 28a and the latter corresponding to the picker stick position at 28b. Between these positions, there is a path of lost motion corresponding approximately in length to that at C in Fig. 1, in which the lug 133 is out of contact with both teeth I30.- More specifically, in Fig. 2, the lug I33 engages the left tooth I30 and turns the sector and hence the piston crank shaft 56 only along a path corresponding to that at A in which the momentum of the shuttle is reduced to zero. In Fig. 3 the lug I33 engages the right tooth I30 and turns the sector 51 clockwise, moving the piston means rightward only for a distance corresponding to the path B in which the picker stick is brought to rest after expelling the shuttle. Hence the following adjustments are possible:

1. By changing the angular distance between the teeth I30, the degree of lost motion between the lever I21 and actuator 61 is changed to adapt the device to looms of different sizes.

2. By varying the position of the left tooth I 30, the position N may be changed thereby changing the length of the path A.

3. By varying the position of the right tooth I30, the position 280 may be changed, thereby changing the length of the path B.

It is noteworthy that the entire device 31 lies within the area of the loom, so that there are no projecting parts to interfere with a closely adjacent loom. For this reason, the ball and socket joint has been brought to the right side of the picker stick, this joint permitting the picker stick to oscillate with the lay 24 in a plane at right angles to the drawing in Fig. 1, and as indicated in Fig. 4, this motion occurring intermediate of the end portions of the travel of the picker stick.

The resistance afforded to' the picker stick upon impact with the shuttle is taken up by the hinge I24 which lies in the plane of the picker stick in Fig. 2 to avoid any tendency to twisting of the picker stick such as occurs with check straps that are mounted at one side thereof and hence have greater yield at the opposite side. The pivotal motion about the axi at I25 allows for any small variations in the elevation of the picker stick as it rocks about the shoe 21. In Fig. 6, the teeth I30 are positioned somewhat difierently than in Fig. 2, and more particularly the right hand tooth of Fig. 2 is shown moved further rightward, in the inverted view of Fig. 6, to thus cause the checking travel B to be less or about one half that at A. The elevation of the linkage I22, I 21 i preferably such that it lies somewhat above the midpoint of the picker stick to avoid deflection and rebound at the lower end of the picker stick. a

The shuttle box 25, although generally or schematically illustrated, 'may be considered to represent such a box modified by omission of the shuttle retarding frictional binder spring which is a metallic strip extending along a substantial portion of the length of the shuttle boxat the rear side thereof in Fig. 1. At the front side of the shuttle box there may be retained the relatively small light strip spring which actuates a movable wall or part of the shuttle box to take up for Wear in the shuttle box and cause'the' shuttle to be snugly held. It is estimated that the binder spring may absorb possibly as much as one half of the momentum of the shuttle,

whereas the action of the second spring mentioned is relatively insignificant in this regard.

Referring to Figs. 17 to 23, inclusive, and taking the outer full dead stop position 28a of the picker stick as a starting point for describing one complete cycle of operations of the hydraulic checking device 31, it will be noted in Fig. 17, that the lug I33 of the lever I21 is in engagement with the inside surface of the left hand tooth I30 of the actuator sector 51, and that the piston structure 54-55 i in a position with the outer end of the piston 54 lying substantially in line with the bleeding port in the cylinder 4-9.

When the picker stick 28 is operated to throw the shuttle 3i across the loom, from left to right as seen in Fig, 1, the picker stick 28 will move freely through the initial power stroke of said stick and carry with it the lever I21, from position #1 through a corresponding segmental portion of the stroke of said lever, which, as seen in Fig. 17, is designated as Power stroke, stick free, until the lug I33 on the lever I21 strikes the inside surface of the right hand tooth I30 of the actuator sector 51, whereupon the actuator sector 61 will begin to be rotated clockwise by the lever I21.

In that part of the travel of the lever I21 designated in Fig. 17 as Stick checking, it will be noted that the stick checking zone of operation of the lever I21 i subdivided into three parts; namely, Initial," Advanced, and Final.

At position #2, where the lever I21 picks up the actuator 60, the angular ports I00 are fully open. However, as the piston structure 53 moves to the right, Fig, 17, into position #3, Fig. 18, initial retardation of the lever I 21, and consequently the stick 28, takes place by reason of the displacement of the liquid fluid contained in the apparatus, from the inside of the hollow piston 55 to the outside thereof, through the ports I00 in said piston.

As the piston 55 moves to the right from position #3, Fig. 18, to position #4, Fig. 19, the ports I00, in the hollow piston 55, are gradually closed by passing the inner edge 49a of the right hand cylinder 49, said edge functioning as a valve or cut-off which gradually reduces the area of the ports I 00 in the hollow piston 55. As the area of the ports I00 is gradually reduced, the escape of the fluid from the interior of the hollow piston 55 is accordingly reduced and results in a corresponding increase in the resistance to the move ment of the piston 55 in theright hand cylinder 49. As the resistance to the movement of the piston 55 in the right hand cylinder 49 increases, a corresponding increase in the resistance to clockwise rotation of the lever I21 ensues, and this is reflected in the resistance to clockwise rocking of the picker stick 28. The movement of the lever I21 from #4, Fig. 19, i noted in Fig. 17.

Final checking of the picker stick 28 occurs as said lever moves from position #4, Fig. 19, into position #5, Fig. 20, as the escape of fluid from the inside of the hollow piston 55 is through the bleeding port 80 in the right hand cylinder 40, solely. The rate of escape of fluid through the right hand bleeder port 80 i minutely controlled by the needle valve 84 operating in conjunction therewith. Consequently, the stick 20 may be brought to a dead stop at any desired place within therefore termed Advance as position.#3, Fig. 18, to position right hand cylinder 49 through the controlled port 89 therein.

From the foregoing it will be clear that during the power stroke of the stick 28 through A plus the greater portion of C, as shown in Fig. 1, the

stick 28 will be free of any retarding effect by.

the hydraulic checking device 31. In that portion of C approaching and adjacent B, preliminary checking of the stick 28 will take place; and during that portion of the stroke designated as B, final checking of the stick will take .place.

In Figs. 21, 22 and 23, the return stroke of the lever I21 in accordance with the return stroke of the stick 28 is shown. From position #5, previously noted, the stick 28 will swing in a counterclockwise direction to position N, Fig. 1, under the influence of the torsion spring I31 and the strap I38. The position N corresponds substantially with position #1 of the lever I21. From position #5, Fig. 21, to position #6, the stick 28 travels free of any retarding effect set up by the hydraulic device 31, as the lug I33 of the lever I21 travels from the right hand tooth |30 of the actuator 61 until said lug engages the left hand tooth I30 thereof.

At position #6, the lever I21 begins to turn the actuator 81 in a counterclockwise direction and initially moves the piston structure 53 to the left from position #6 to position #7 as shown in Fig. 21. During this initial movement of the actuator 61 and piston structure 53, the fluid within the hollow piston 54 escapes rather rapidly through the wide open ports 99 therein until the leading upper left hand corners of the angular ports 99 arrives at the cut-off edge 49b of the left hand cylinder 49, as shown in Fig. 22, nevertheless such displacement of the fluid through the ports 99 does apply a minor retarding effect to the movement of the lever I21 and consequently to the stick 28.

During the travel of the shuttle 3| fromthe right side of the loom to the left side thereof, under impetus of the picker stick located at the right side of the loom, the forwardly moving front end of the shuttle 3| will engage the picker 30 On the picker stick 28, at such time as the picker stick is approximately at position N, Fig. 1, while the lever I21 is being moved from position #6 to position #1, Fig. 21, by the outwardly moving picker stick 28, whereupon Initial retardation of the lever I21 and stick 28 will be inaugurated.

As the lever I21 reaches position #7, Fig. 21, the advance corners of the angular ports 99 in the piston 54 .will have arrived at the cut-off edge 49b of the left hand cylinder 49, as shown in Fig. 22.

As the movement of the piston structure 53 continues to the left, and the angular ports 99 pass under the cut-off edge 4491), the escape of fluid through the ports 99 is gradually reduced and the resistance to the leftward movement of the piston 54 and lever I21 are correspondingly gradually increased until the trailing corners IIII of the ports 99 pass the cut-off edge 4%, and cut off all escape of fluid through said ports. Thus the lever I21, and the stick 28, passes through the Advanced stage of checking.

When the trailing corner IIlI of the ports 99 pass under the cut-off vedge 4%, the escape of left hand cylinder 49, under control of the needle valve 9| associated therewith.

Thus the lever I21 passes into the "Final checking stage (Figs. 21 and 23) as the stick 28 passes into the checking stage A (Fig. 1). By manipulating the needle valve 9| associated with the bleeding port 80 of the left hand cylinder 49, the stick 28 may thus be brought to a dead stop at any point desired in the checking segment A, and the lever I21 consequently checked and stopped dead at any point between position #8 and position #1 in Fig. 21.

As the liquid fluid in the hydraulic device 31 is preferably of an incompressible nature, there will be no rebound of the stick from its dead stopping point. Thus, no rebound of the shuttle 3| will take place as it is at such time gripped sufficiently by the laterally acting light spring in the shuttle box to overcome any tendency of the shuttle to rebound from the picker carried by the stick 28.

It will be understood that, as the piston struc-' I ture 53 moves to the right and the piston 55 befluid from the interior of the left hand cylinder comes effective to check the stick 28 in its movement in the same direction, after having started the shuttle 3| on its way across the loom toward the right side thereof, the interior of the piston 54 is refilling with fluid being drawn through the check valve opening 16, and vice versa, so that each cylinder 49 and its associated

piston

54 or 55 as the case may be will be ready for immediate operation when the stick 28, lever I21 and piston structure 53 change direction of movement. So precise is this hydraulic control that the picker stick is accurately and unfailingly stopped at positions 28a and 28b. Actual tests have shown its sensitivity. By placing indicators on the shuttle and shuttle box and manipulating the key 98 while the loom was in operation, it was possible to observe the shift in the position 28a. of the picker stick. Such results were obtained with the bleeder valve of Fig. 14. Figs.

15 and 16 are considered to possess the advantages of a normally complete closure to avoid even the most minute movement except under substantial power. Fig. 15 is believed to possess the advantage in that the graphic slope of the resistance increases as the momentum is expended; after a substantial part of the momentum has been absorbed, the danger of rebound of the shuttle is less, and hence the resistance may be proportionally increased, thus diminishing the checking path A and permitting the speed of the loom to be increased. Fig. 16 is like Fig. 14 in affording a predetermined positive bleeding position. It is believed that the full spring control of Fig. 15 has a further advantage over the positive adjustment of Figs. 14 and 16 in that a slight variation in the day by day condition of the loom may be less critical in its effect on the checking along path A so that adjustment of the bleeder valve may occur less frequently or might be wholly obviated; in other words the device of Fig. 15 will have the proper flexibility within the narrow limit permitted by the loom to afford continued satisfactory operation with little or no adjustment. A surprising factor in this invention is that it was possible to omit the binder spring, whereby the speed of the loom directly increased, because more power became available and a source of friction was eliminated. The heat generated in the liquid has been found to be so small, as the temperature need not bemore than between 100 and degree F., that it may be disregarded, as the heat is readily dissipated by picker stick is free of the piston means.

unit cushions againste rcessive impact of the lug I33 of the lever I21 on the teeth I30 of the sector 61. Such cushioning is especially assisted by the spring closed bleeder valves. These teeth may be individually and collectively adjusted to vary the paths A, B and C for difierent looms. Due to the lost motion engagement in which the piston means is at rest, such adjustment is facilitated, and wear on the piston is diminished, because the travel of the piston i greatly reduced. The device may also be made much smaller. Furthermore, there is no impediment to the power thrust of the shuttle on the picker stick because during such motion along paths A and C, the Durin the movement of the picker stick by the shuttle, the resistance of the hydraulic unit is imparted by the linkage I22, I21 substantially squarely in the plane of the picker stick so that there is no twisting action on the latter. By the provision of angular openings 99 and I Win the pistons ro- .tation iscaused for even distribution of wear. A

complete liquid circulatory system is provided for each piston through outlet 80, passage 8|, past 7 the interrupted flange 15 of the end plug 14, thence through passages 52 to the openings 99, I into the cylinders 49, and also from within the area of the interrupted flange 15 through the check valve unit into the cylinders 49. The hydraulic unit 31 is reversible for use at either end of the loom by interchanging the

bleeder devices

82, 33 and by disconnecting the lever I21 from the rocker shaft 56 to position it in upside down relation to the cylinder 38- and the sector 61. Both casing sections 39 are identical and so are the pistons, check valve units, plugs, and even the crank shaft is reversible so that the shaft 56 may be received in either of the

identical split hubs

42, 43. I

It will thus be seen that a device has been provided which avoids the erratic action of a check strap, which is subject to rapid wear with consequent increase in its haphazard action. It is also seen that the device avoids the resilient action of proposed old pneumatic devices which afford entirely too little resistance when it is most required and afiord greater resistance when less is needed, and which store power to prematurely advance the picker stick instead of afiording a condition of zero energy as the shuttle comes to rest. It may be added that pneumatic devices cannot afford the accurate positioning of the picker'stick herein attained. While it is submitted that pneumatic action is not feasible and has not proved practical, it may be pointed out that certain features of the invention, such as the lost motion action, may be practised with pneumatic devices. Although the device herein disclosed is double acting, it is to be understood that the most important feature of the invention resides in checking the momentum of the shuttle along path A, with or without checking of the picker stick as along path B.

It will be understood that the shuttle loses velocity in traveling across the lay of the loom so that the velocity at which the picker stick receives the shuttle may be substantially less than that at 16 0f the shuttle to thus include the energy of both. Because the picker stick lies in an upright plane along the shuttle path, the meandistance of which plane from the vertical axis of the crank shaft of the hydraulic brake is relatively constant, the movement of the piston means is directly proportional to that of the picker stick. In fact, along paths A and B, the picker stick moves almost wholly in a vertical plane. The leverage at the linkage is shown to be approxilnately 4, and this should. be doubled by the leverage of the picker stick. Hence the brake pressure is obviously very high. The bleeders should be of such size that the brake pressure will not become so high as to cause rebound. In any event, the liquid pressure becomes zero instantly with the termination of the checking action along paths A and B. The high pressures involved may also be obtained with rotary positive pressure hydraulic brakes, and the lost motion action furnished by interrupted gears or racks, but that structure does not lend itself to the simplicity and compactness obtained with a. reciprocating hydraulic unit a herein disclosed.

I claim:

1. A device including a projectile-like element, means including a member movable to and fro along a predetermined path, said member serving to receive the impact of the element to be thus moved thereby to one end of said path from which position said member is capable of a power qstroke for inaugurating movement of and prowhich it is projected. More particularly, the

jecting said element freely therefrom at a predetermined velocity, means for causing the power stroke of said-member; energy absorbing means for absorbing the momentum of the member including the momentum imparted thereto by said element to quickly bring both to a condition of rest at the said end of said path, said energy absorbing means comprising a liquid filled positive pressure brake adapted to trap said liquid and having a restricted outlet for controlling flow of the liquid therefrom, said brake being actuated by said member so that a principal part of the said momentum is expended in forcing the liquid through said outlet, the pressure on the liquid being reduced substantially to zero instantaneously with the reduction to zero of said momentum by the energy absorbing means, and means rendering said brake incapable of impeding the movement of said member during that portion of the power stroke thereof preceding the projection of said element therefrom, and the said outlet affording such resistance to the liquid that the brake constitutes substantially the sole agency for causing the member and element to stop at said end of said path, without rebound, so that the member is in the position necessary for said movement inaugurating and projecting of the element at said predetermined velocity.

2. A device according to claim 1 wherein said brake is double acting and serves to co-act with the member to absorb the momentum thereof at the other end of said path after the element has been projected by the member, and lost motion means interengaging the member and the brake to cause the brake to exert pressure on the liquid solely when the member approaches the ends of its path.

3. A loom including a shuttle, means including a picker stick movable along a path to receive the impact of the shuttle at a point intermediate of the ends of the tie to an outer end of said path from which position the picker stick is capable of moving toward path to be moved by the shut the inner end of the path in course or inaugurating movement or and projecting the shuttle freely therefrom at a predetermined velocity, means for absorbing the energy of the picker stick including the energy imparted thereto by the absorbing means to bring the picker stick and shuttle to rest at the outer end of said path, the

pressure on the liquid being reduced substantially to zero when the said condition of rest is attained, and said orifice being of such size that the brake causes the picker stick and shuttle to stop without rebound at a predetermined point at the outer end of said path, and means rendering said brake incapable of impeding the movement of said picker stick during said movement inaugurating and shuttle projecting of said picker stick.

4. An automatic bobbin loading loom including a shuttle, a picker stick therefor, means for causing a power stroke of the picker stick after the latter has received the shuttle and has been moved by the shuttle to the outer end of its stroke, means for absorbing the momentum of the picker stick including that applied thereto by the shuttle, comprising a liquid filled positive pressure brake for absorbing the principal part of said momentum to bring the picker stick and shuttle to rest, the brake having a flow control outlet orifice such that said brak constitutes substantially the sole means for determining the precise point of rest at said outer end\of the fiow control outlet orifice stroke, with the orifice causing the liquid to offer a hydraulic resistance of relatively constant slope in bringing the picker stick and shuttle to rest without rebound, whereby the shuttle is capable of automatic bobbin loading and of being projected by the picker stick with a predetermined impulse caused by the first mentioned means, and actuating means for said brake being so related to the picker stick that the latter is free of liquid resistance during the movement inaugurating and shuttle projecting portions of its power stroke.

5. A loom according to claim 3 wherein said brake is also coordinated with the picker stick to cushion the latter as it approaches the inner end of its path after having projected the shuttle, and lost motion means acting between the brake and the picker stick such that the picker stick returns to its intermediate position and moves on the movement inaugurating and shuttle projecting portions of its power stroke free of resistance of the liquid in the brake.-

6. A loom according to claim 4 wherein said brake is double acting to also absorb the energy of the picker stick after projecting the shuttle, and lost motion means interengaging the brake and the picker stick so that the brake affords liquid resistance only when the picker stick approaches the ends of its path.

7. A loom having a shuttle, a for, a positive pressure brake having bleeder means for checking the motion of the picker stick as it approaches the ends of its path and being free of the picker stick along its to-andfro intermediate travel, means for actuating the brake in synchronization with the said brake being double acting, and said means picker stick therepicker stick,-

18 including lost motion means comprising spaced elements at least one of which is adjustable to vary its position, said elements co-acting with the picker stick for actuation thereof as the picker stick approaches the respective ends of its path.

8. A loom having a. shuttle, a picker stick therefor, actuator means for causing a power stroke of the picker stick and for causing a return movement of the same to shuttle receiving position, and energy absorbing means independent of the actuator means for absorbing the momentum of the received shuttle, and of both ends of the path of the latter, including a liquid filled, double acting positive pressure brake having different bleeder means for checking the picker stick at difierent ends ofits path, a piston means driven by the picker stick and having pistons for the respective bleeder means, individual cylinders for the pistons, check valves for the individual cylinders, a reservoir between the cylinders communicating with the bleeder means and with the check valves, the reservoir having direct communicating means with the cylinders cut off by advance strokes of the respective pistons, a crank shaft in the reservoir engaged with the piston means, and lost motion means engaging the crank shaft with the picker stick to cause movement or the piston means only when the picker stick approaches the ends of its paths.

9. A loom according to claim 8 wherein the bleeder meansfor the different cylinders afiord openings of different sizes, the bleeder means for checking the inward movement of the picker stick after projection of the shuttle cooperating with the said communicating means for its cylinder to cause checking of said inward movement of the picker stick. I

10. A loom according to claim 8 wherein the said communicating means including angular openings differently sloped in the different pistons, the latter being hollow, whereby advance movements of the pistons cause the. liquid to tend to rotate the piston means for even wear there- 11. A loom according to claim 8 wherein the lost motion means includes reversible means detachable from the crank shaft whereby the double acting brake can be interchangeably associated with a picker stick at either end of the loom.

12. A loom according to claim 8 wherein the lost motion means includes an oscillatory member and an teeth between which said member oscillates, the limits of lost motion being determined by engagement of the oscillatory and the action of the bleeder means serving to cushion the engagement of the oscillatory member with said teeth.

13. A loom having a shuttle, a picker stick therefor, a liquid filled positive pressure brake havin bleeder means and being actuated by the picker stick to check the same at a predetermined point, as determined by the bleeder means, without rebound of the shuttle,.means for circulation of the liquid so cooperating with the brake that the picker stick is free of brake resistance during an initial predetermined portion of its power stroke, means constantly connecting and acting between the picker stick and the brake to effect delayed return of the latter to initial position after completion of the power stroke of the picker stick, and independent means for means to determine the precise point at which the said checking movement.

the picker stick at element having adiustably spaced member with said teeth,

adjusting the bleeder '14. A loom having a shuttle, a picker stick therefor, a liquid filled double acting positive pressure brake for checking the picker stick as the latter approaches the outer and inner ends of its path of travel, means constantly connecting said,

picker stick to said brake and including means rendering said brake ineil'ective' during predetermined initial portions of each of said paths, the brake having bleeder means for the difi'erent checking actions, the brake having difierent portions for forcing liquid through respective bleeder means so cooperating with the latter as to aflord different checking forces for the picker stick at the diilerent ends or its path of travel, and check valve means associated with said diflerent portions.

15. A loom having a shuttle, a picker stick therefor, a liquid filled, positive pressure brake actuable by the picker stick, the brake having a bleeder means whereby the momentum of the shuttle is absorbed, and a spring Dressed valve for the bleeder means. v

16. A loom comprising a reciprocable shuttle, an oscillatory picker stick adapted to be engaged and moved in one direction by said shuttle and to drive said shuttle in the opposite direction inclined to said axis, whereby said displacement will be gradually reduced during axial movement of said piston in one or said directions relative to said cylinder.

17. A loom comprising a reciprocable shuttle,

the movement of said stick 1 filled cylinder, an inner pressure brake for an oscillatory picker stick adapted to be engaged V and moved in one direction by said shuttle and thereafter drive said shuttle in the opposite dithe axis of said inner cylinder,

a device for checking in at least one oi said directions, said device comprising an outer liquidcylinder fixed in said outer cylinder, a piston axially operable in said inner cylinder, a hquid port in said piston having a valving 'suriaoe disposed at an incline to a valving surface one end of said inner cylinder subat right angles to said axis and cooperating with the first said valvins surface to reduce the area of said port and consequently the rate at said displacement during relative axial movement of said piston relative to said inner cylinder.

18. A loom having a shuttle, a picker stick therefor, a liquid filled double acting positive checking the picker stick as the latter approaches the outer and inner ends oi its path of trav means constantly connecting said picker stick to said brake, means rendering said brake substantially ineffective during predetermined initial portions of each of said paths, the brake diiiei'ent checking actions, the brake having different portions for forcing liquid through respective by-pass means socooperating with the latter as to aflord difierent checking forces for the picker stick at the diiferent ends of its path or travel, and check valve means associated with one 01' said different portions.

'O'ITO A. K 'I'IEMANN.

REFERENCES CITED The following references are of record in the motion across said loom,

formed at stantially file of this patent:

UNITED s'm'ms PATENTS Number Name Date 677,562 00mins July 2, 1901 1,765,314 Stuart June 17, 1930 2,354,340 Utter July 25, 1944 1,260,405 Krussell Mar. 26, 1918 2,160,339 Moessinser having by-pass means for the p