US2593302A - Weft yarn ensnaring apparatus for automatic looms - Google Patents

Description

April 15, 1952 L. L. HAWKINS 2,593,302

WEFT YARN ENSNARING APPARATUS FOR AUTOMATIC LOOMS Filed. Jan. 2, 1951 s Sheets-Sheet 1 [501mm L. #0 w/r/n/s,

INVENTOR ATTORNEYS.

April 15, 1952 L. L. HAWKINS WEFT YARN ENSNARING APPARATUS FOR'AUTOMATIC LOOMS Filed Jan. 2, 1951 3 Sheets-Sheet 2 4 I 5; w .a

-rIO

LEONA/f0 L. l/nwmvs,

INVENTOR.

BY 5% W/ ATTORNEYS.

April 15, 1952 L. L. HAWKINS WEFT YARN ENSNARING APPARATUS FOR AUTOMATIC LOOMS Filed Jan. 2, 1951 3 Sheets-Sheet 3 150m e0 L llqwmvs,

INVENTOR.

BY {,AMW

ATTORNEYS.

Patented Apr. 15, 195 2 UNITED STATES PATENT OFFICE WEFT YARN ENSNARING APPARATUS FOR AUTOMATIC LOOMS Leonard L. Hawkins, Greenviile, S. C.

Application January 2, 1951, Serial No. 203,942

7 Claims. 1

This invention relates to automatic filling replenishing looms and more especially to a weft yarn ensnaring apparatus therefor which operates in conjunction with the bobbin transfer mechanism thereof.

It is well known to those familiar with the art that most automatic filling replenishing-looms are provided with automatic thread clamping and cutting means for operating upon the filling yarns adjacent a boxed shuttle at the time of transfer, the type of clamping and cutting apparatus being generally known as a Stafford thread-cutter. Such looms are also usually provided with a temple thread-cutter which is disposed immediately adjacent the selvage of the fabric being woven and which is provided with a hook-shaped yarn ensnaring cutter which is adapted to cut the portions of the yarn which extend from the filling replenishing apparatus to the selvage of the fabric being woven after about two picks have been woven following a bobbin transfer operation.

However, it often happens that this particular type of a thread-cutter is disposed above the horizontal plane of the lay and unless the yarn extending from the Stafford thread-cutter to the selvage of the fabric is held relatively taut, this yarn may not be engaged by the temple thread-cutter. Also, the yarn may be pulled back into the shed formed by the harnesses causing a defect in the woven fabric commonly referred to as jerked-in filling.

It is therefore the primary object of this invention to provide an automatically operable yarn ensnaring apparatus which comprises a spring loaded movable arm provided with an upwardly projecting hook portion on the free end thereof adjacent the lay and which is released automatically in the course of a bobbin transfer operation to permit the same to rest upon the lay upon a beat-up stroke thereof. This will result in the filling extending across and resting atop the hook of the yarn ensnaring apparatus and, with further forward movementof the lay, means are provided on the arm of the yarn ensnaring apparatus which is engageable by the lay for moving the arm forwardly and upwardly to thus cause the yarn ensnared thereby to be directed to the temple thread-cutter. The bobbin transfer mechanism is provided with means for again engaging the arm of the yarn ensnaring apparatus to prevent the same from returning with the lay upon a subsequent backward stroke thereof and thus insuring that the yarn ensnaring apparaus will not interfere with 2 normal operation of the shuttle as it is thrown across the lay.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds when taken in connection with the accompanying drawings, in which- Figure 1 is a fragmentary top plan view showing the front right-hand corner of a loom and a portion of the automatic bobbin transfer apparatus associated therewith and also showing the improved yarn ensnaring or catching ap paratus in association therewith;

Figure 2 is an elevation of the improved yarn ensnaring apparatus with parts of the loom being shown associated therewith in cross-section and being taken looking substantially along the line 2-2 in Figure 1, the lay being shown in a rearward position;

Figure 3 is an enlarged view similar to Figure 2 but showing the lay in a beat-up position;

Figure 4 is an enlarged fragmentary elevation looking at the front of the loom and being taken substantially along the line 4-4 in Fig-i ure 1;

Figure 5 is a fragmentary elevation, looking along the line 55 in Figure 1, showing a portion of the temple thread-cutter;

Figure 6 is an isometric view of the improved yarn, ensnaring apparatus removed from the loom for purposes of clarity and looking substantially in the direction of the arrow, 6 in Figure l.

Referring more specifically to the drawings, the numeral I0 broadly designates the frame of the loom and which includes a right-hand side frame member II to the front end of which one end of a breast beam I2 is suitably secured. This breast beam supports one end of a cloth take-up roll 14 which has conventional means, not shown. associated therewith for taking up and maintaining tension in a woven fabric F. This fabric F is formed from warp yarns W a few of which are shown in Figure l, and also being formed from weft or filling yarns which are fed from a bobbin 20 in a shuttle 2]. The shuttle 21 is adapted to be moved along a race plate 22 on the upper surface of a lay 23 by means of a picker 24 mounted on the upper end of a picker stick 25, only a portion of which is shown in Figure 1. The shuttle 2| is shown in Figure 1 disposed in a shuttle box broadly designated at 26.

The lay 23 is supported in the usual manner on a pair of spaced swords 21, only one of which is shown in Figures 1, 2 and 3, which is driven by the usual devices including a pitman rod or connector which is pivotally connected to the swords 21 as at 3!. port opposed ends of a reed cap 32 and a suitable reed 33 is mounted between the reed cap 32 and the lay 23 for beating the weft or filling yarns into the fell of the cloth.

It will also be observed, in Figures 1 and 4,

. that the right-hand end of the breast beam l2 has the foot of a magazine or battery broadly designated at 36 suitably secured thereto as by screws 31. This magazine 36 may be of a type substantially as shown in the patent to Stafford No. 1,568,481. Also shown in said patent is a thread clamping and cutting apparatus, a portion of which is shown in Figure 1 of the present drawings and which is indicated at 41.

This clamping and cutting device is adapted to clamp and cut a strand of filling yarn S-'l which is the final strand thrown acros the lay 23 immediately preceding the replacing of an exhausted bobbin in the shuttle 2!. The magazine 35 usuallysupports a plurality of bobbins, as is well known to those familiar with the art, and the yarn extends therefrom to 'a yarn holder 4i and, upon transfer of a bobbin and as the shuttle 2| is subsequently thrown from right to left across the lay 23, a strand of yarn S-Z extends from the yarn holder M to the selvage of the fabric being 'wove'n as is clearly shown in Figure 1. The bobbin is transferred from the magazine by the usual transfer arm 42 (Figure 1) and associated parts not shown. 7

Now, the "breast beam I2" also supports a coni'ng portion 46 thereon through which the fabric F passes upon beat-up strokes of the lay 23. This temple may be of any desired construction and is provided with a down-turned hook thread-cutter 41 which is automatically operable upon each beat-up stroke of the lay to cause the same to recede into the temple per se to thus sever either orboth of the strands of filling yarn S-l and 8-2, provided that they have been directed thereto i'na proper manner. This temple threadcutter may be of a type substantially as shown in the patent to Stimpson,. No. 1,552,016 of September l, 1925, although it is to be understood that there are many other types of thread-cutters with which the present apparatus may be associated.

As is clearly shown in said Patent No. 1,568,481,

the automatic transfer mechanism, including the threadecutter 40 and the bobbin transfer arm 42, is rendered operable by means of a shipper or transfer shaft which is mounted in suitable bearing blocks 5|, each of' which is suitably secured to the front surface of the breast beam [2, asby a screw 52, there being only one of these bearing blocks shown in Figures 1 and 4. I The parts heretofore described are the usual parts of an automatic filling replenishing loom and it is with these parts that the present. invention is particularly adapted to be associated.

The improved thread catcher or yarn ensnaring. apparatus comprises a base which may be. of cast construction but is shown as bein ofbuilt-up construction in the drawings, and to the upper surface of which a guide block 56 having a vertically extending'slot 51 therein is suitably secured, as by a screw 66 It will be noted in Figure 4 that the breast beam I2 is off-set, as

V at 6|, thus providing a space in which a nut 62 threadably mounted on'the lower end of a screw 7 6 may be disposed. The base 55 is provided with The swords 21 also sup- 7 ventional temple, broadly designated at 45, which extends forwardly and has an inwardly project- ,a forwardly and rearwardly extending slot Bl which is penetrated by the screw 63, this screw 63 serving as a stop member for the front end of a forwardly and rearwardly extending yarn ensnaring arm broadly designated at $5.

This yarn ensnaring arm includes a forwardly and rearwardly extending shank portion 66 which has a laterally extending latch'engaging projec- 7 tion 6? on the front end thereof, the purpose of which will be later described. The shank portion 6d of the yarn ensnaring arm 55 extends rearwardly and is then bent downwardly and rearwardly to form a downwardly and rearwardly extending angularly disposed portion 10 and then extends rearwardly, as at H, in the same vertical plane as the shank portion 56. The rear end of the portion H is provided with an upwardly and forwardly extending hook portion 12 which is adapted to ensnare either or both of the lengths of weft yarns Sl or 8-2 in a manner to be later described.

A suitable spring anchor 14" is suitably secured, as by welding, to the upper surface of the shank portion 56 of the arm 65' adjacent the laterally projecting portion 6?, by any suitable meanssuch' as welding. This spring anchor'hi has the front end of a tension spring 15 connected thereto which extends rearwardly and has its other end connected to a spring anchor portion 16 projecting from the upper surface of the guide block 56.

The shank portion 65 of the arm 65 is mounted for vertical and horizontal sliding. movement in the slot 5'! of the guide block 55. When the yarn ensnaring arm 65 is in an inoperative position substantially as shown in Figures 3 and 6, it is held in engagement with the screw 53, serving as a stop member, by means of a leaf spring latch member 11 which engages a laterally projecting portion 6? of the arm 65' and extends forwardly and is suitably secured, as by a screw 80, to the upper end of a latch support arm 8|; The spring latch 11 has a downwardly projecting protuberance 181onits free end which rides over the laterally extending portion 61 to hold the member 65 in the position shown in Figures 1, 3 and 6.

The. latch support arm 8| extends downwardly (Figures 2, 3 and 4') and is adjustably'secured, as by a set screw 82,,to the transfer shaft 55 heretofore described.

In order to insure that the leaf. spring latch member i! may engage the laterallyextending projection 611 of the arm 65 so as to hold the arm '65 against the screw 63, an adjustment screw 83 threadably penetrates the upper portion of the arm 81 in Figure 3 and is heldin adjusted position bya lock: nut 84. The head of this adjustthe breast beam l2 when the'leaf spring latch member 11 is in engagement with. the laterally extending projection 61 of the arm 65.

To further assist in guiding the yarn ensnaring arm 55; the front end of the shank portion 66 of the yarniensn'aring arm 65 has a downwardly'pro jecting portion 8% thereon which slidably penetrates the slot 6 and the lower end of which is bent-towards the observer in Figure 3, as at 1, so as to insure that the front end of the yarn ensnaring arm 55 will remain in close proximity to the upper surface of the base 55 with forward andrearward movement thereof. i In a bobbin transfer operation inorder to con' di'tion the various parts of the bobbin transfer mechanism of the loom, the transfer shaft50 is caused to rotate a partial revolution ina' clockwise direction substantially from the position shown in Figure 3 to substantially the position shown in Figure 2. This results in the leaf spring latch member 11 being biased as it is also moved forwardly so as to release the projection 61 of the arm 65, thus permitting the arm 65 to move rear- -wardly under tension of the tension spring 15.

At the same time that the arm 65 moves rearwardly, there is provided on the shank portion 66 of the arm 65 an outwardly projecting guide portion 90 which enters the slot 51 in the guide block 56 thus insuring that the hook portion ll of the arm 65 will remain in a lowered position since any tendency to move the hook portion H upwardly would cause the upper surface of the guide portion 90 to engage the upper wall of the slot 51 in the guide block 56.

It will be observed in Figures 2 and 3 that the shank portion 66 of the yarn ensnaring arm 65 has a pair of downwardly extending angularly disposed cam projections 01' extensions 92 and 93 thereon. The cam projection 92 extends downwardly and forwardly at a slight angle relative to the vertical from a point adjacent the angul arly disposed portion of the arm 65 and the cam extension 93 extends from a point on the shank portion 66 of the arm 65 substantially forwardly of the point from which the cam extension 92 projects and this portion 92 then extends rearwardly and downwardly at an angle and is connected intermediate the ends of the portion 92.

Now, this yarn ensnaring arm 65 is adapted to be moved forwardly and upwardly at the hook end thereof upon a beat-up stroke of the lay 23 subsequent to the arm 65 having been released from the leaf spring latch member 11 in the manner heretofore described. The lay 23 may engage the cam extension 92 if so desired. However, it is preferable to provide a hunter 95 which is suitably secured to the front surface of the lay 23, by a screw 96, and the upper end of which extends forwardly to provide a relatively narrow edge, as at 91, for engaging the portion 92 of the arm 65.

Rearward movement of the yarn ensnaring arm 65 is restricted since the projection 86- at the front end thereof will engage the rear wall of the slot 64 in the base 55. Thus, upon a backward stroke of the lay 23, it will move substantially away from the hook end 12 of the arm 65 and, in the course of the subsequent beat-up stroke of the lay 23, the shuttle 21 will have ample time in which to move past the hook portion 12 of the arm 65, as it is being thrown into the shuttle box with respect to the selvage of the fabric F, as

26, to prevent the shuttle 2| from engaging the i hook portion 12 of the arm 65. With further forward movement of the lay 23, the edge 91 of the hunter 95 will engage the cam extension arm 92 integral with the yarn ensnaring arm 65 and will thus cause the yarn ensnaring arm 65 to move forwardly.

As the yarn ensnaring arm moves forwardly, the cam portion 93 thereon engages the rear edge of the base and this causes the hook portion 12 at the rear end of the arm to move upwardly as it is moved rearwardly.

Upon a bobbin transfer operation taking place, in which a new bobbin is transferred to the shuttle 2|, the filling end S-l left by the old bobbin will be gripped by the thread-cutting and clamping device 40 causing the same to extend at an angle with respect to the selvage of the fabric F as shown in Figure 1. Likewise, the filling end 8-2 from the new bobbin transferred to the shuttle 2| will extend from the yarn holder M at an angle shown in Figure 1.

Now. the arm BI is not moved forwardly to the position shown in Figure 3, from the position shown in Figure 2, until the shuttle t2l is again returned to the shuttle box 26 following a bobbin transfer operation and, consequently, the yarn ensnaring arm 65 will again move from substan-. tially the position shown in Figure 3 to substan-. tially the position shown in Figure 2 and will again be moved to the position shown in Figure 3 upon the next forward or beat-up stroke of the lay. It is thus seen that both of the yarn or fill ing ends S-l and 3-2 will be ensnared by the hook portion 12 of the arm 65 and will be caused to move forwardly and upwardly to thus be directed to the hook 41 of the temple thread-cutter in the temple .45. Thus, the yarn filling ends S-l and 8-2 will subsequently be severed by the temple thread-cutter 4! immediately adjacent the selvage of the fabric F and, upon subsequent movement of the shuttle 2| from right to left across the lay, the possibility of the yarn filling ends 8-1 and S-2 being thrown into the shed formed and beat-up into the fell of the cloth is eliminated.

It is thus seen that I have provided an im-- proved filling yarn ensnaring device which is automatically operable upon a bobbin transfer operation taking place and the hook portion of which will, due to its upward and forward movement, cause the yarns ensnared thereby to be directed to the hooked temple thread-cutter 41 in an upward direction thus insuring that the yarn will be properly engaged by the temple thread-cutter and thus be severed thereby.

In the drawings and specification, there has been set forth a preferred embodiment of the invention and although specific terms are employed, they are used in a generic and descriptive sense only, and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. In a loom having a frame, a lay, a transfer mechanism, a hooked member mounted on the frame and being slidable in the direction of travel of the lay, tension means normally urging the hooked member rearwardly in the loom, latch means for preventing such rearward movement, cam means on the hooked member engageable by a loom part for elevating the hooked member and means automatically operable upon the transfer mechanism being activated for moving the latch means to unlatching position.

2. In an automatic filling replenishing loom having a bobbin transfer mechanism and also having an oscillatable lay and also having a temple thread cutter, an improved apparatus for ensnaring the filling ends which extend between the selvage of the fabric woven on said loom and the bobbin being expelled and the bobbin being installed by the bobbin transfer mechanism and for directing the filling ends to the temple thread-cutter comprising a forwardly and rearwardly movable yarn ensnaring arm carried by the loom, means normally holding said arm in an inoperative position, means automatically operable upon a bobbin transfer operation taking place for moving said arm into operative position to where the same will extend across the lay in the course of a beat-up stroke thereof, said arm having an'jupwardly extending hook on the free end thereof adjacent the lay, means on said arm engageable by the lay as it continues in a beat-up stroke for moving said arm with the lay and means on the arm adapted to engage the loom for moving the free end of said arm upwardly with'said continued beat-up movement of the laywhereby the filling ends resulting from abobbin transfer operation will be ensnared by V the hook on the free end of the arm and directed upwardly to be introduced to the temple threadcutter: and to besevered thereby.

3; In a loom having an automatic filling replenishing mechanism and also having an oscillatable lay for weaving fabric and also having a templethread-cutter and also having a frame, an improved apparatus for ensnaring the'filli-ng ends which result at transfer in a loom and for directing said filling ends to the temple threadcutter comprising a forwardly and rearwardly extending yarn ensnaring arm having an upwardly facing hook on the free or rear end thereof adjacent the lay, means fixed on the frame of the loom -for supporting the forwardly and rearwardly extending arm for sliding movement therein, spring means normally urging the arm in a horizontal direction towards the lay of the loom, means restricting movement of said arm towards the lay so the spring means will normally urge the hook thereon to occupy aposition substantially midway of a beat-up stroke of the lay, means responsive to a beat-up stroke of the lay for moving the hook on the end of said arm in the direction of movement of the lay and to cause the same to move upwardly simultaneously, means engaging said arm to normally hold the same in a forward position away from the lay, means automatically operable upon a transfer operation for releasing said arm to permit said spring means to move said arm so as to assume a position where the filling ends will lie across said arm in the course of a beat-up stroke of the lay and will be ensnared thereby and with continued movement of the lay in a beat-up stroke, the hook on the arm will move with the lay while also moving upwardly to thus direct the filling end ensnared by the hook portion thereof to the temple thread-cutter to be severed thereby.

4. In an automatic loom having a breast beam and also having an oscillatable lay and also having an automatic bobbin transfer mechanism, an improved apparatus for ensnaring the filling ends which occur as'a result of a bobbin transfer operation comprising a base secured to the breast beam, an arm mounted for forward and rearward movement in the base, said arm having an upwardly facing hook portion on the free or rear end thereof and being disposed in substantially the horizontal plane of the upper surface of the lay, spring means normally urging the arm rearwardly' towards the lay, stop means restricting movement of said arm to where the hook portion thereof will be disposed substantially midway of a beat-up stroke of the lay, a downwardly extending cam portion on said arm, means on the lay adapted to engage said cam portion to impart forward movement to the arm inthe course of a beat-up stroke of the lay, a second cam means on said arm disposed forwardly of and adapted to engage. the adjacent edge of the base of the'apparatus to cause the arm to move upwardly in the course of its forward movement as imparted thereto'by the lay, means associated with the automatic filling replenishing mechanism for engaging said arm and holding the arm in a forward position upon a backward stroke of the lay, and means automatically operable uponthe occurrence-of a bobbin transfer operation for releasing said arm to permit the spring means: associated therewith to again move the arm rearwardly to operative position whereby, uponthe occurrence of a bobbin transferoper-ation, the filling ends resulting therefrom will be ensnared by the hook portion of the forwardly and rearwardly extending arm, and carried forwardly and upwardly thereby and thus be directed to the: temple'thread-cutter to be. severed thereby.

5.- In an automatic filling replenishing loom having a bobbin transfer mechanism and also having an oscillatable lay and also having a. breast beam at the front of the loom and also having a. thread-cutting temple supported on the breast beam adjacent the sel'vag e of' the fabric being woven, an improved apparatus for ensnaring the filling ends which occur between the selvage of the fabric and the bobbin transfer mechanism for directing said filling ends to the thread-cutting templev comprising a base secured to the breast beam and having a longitudinally extendingv vertically disposed. slot therein, a forwardly and rearwardly movable yarn ensnaring'arm supported on the base and being providedwith a downwardly projecting portion at the front end thereof mounted for longitudinal sliding movement in said slot in the base, said downwardly projecting portion; having means on the lower end thereof: to hold' the front end of the arm in engagement with the upper surface of said base, a. latch engaging. projection integral with; the front end of said arm, latch means carried by the loom normally engaging said latch engaging projection on the arm, means controlling the latch means responsive to a bobbin transfer operation for releasing the arm from said latch means, spring means urging the arm rearwardly towards the lay upon the arm being released from the latch means, a hook projection on the free rear end of said arm and being disposed immediately above the lay as the lay moves'in a beat-up stroke and at a point substantially midway of a beat-up stroke of the lay, means on said arm engageable by the lay as it continues inabeatup stroke for moving said arm with the lay and means on said arm adapted to engage said base for moving said arm in an upward arc with said continued movement of the lay whereby said filling ends will be ensnared by the hook on the rear end of the arm and are directed upwardly to beintroduced to the thread-cutting temple to be severed thereby.

6. Inan automatic filling replenishing loom having a bobbin transfer mechanism and also having an oscillatable lay and also having a breast beam at the front of the loom and also having a thread-cutting temple supported on the breast beam adjacent the salvage of the fabric being woven, an improvedapparatus for ensnaring the filling ends'which occur between the selvage of the fabric and. the bobbin transfer mechanism for directing said filling ends to the thread-cutting temple comprising a base secured to'the breast beam and havlng'a longitudinally extending vertically disposed slot therein, a forwardly and rearwardly movable yarn ensnaring arm supported on the base and being provided with a downwardly projecting portion at the front end thereof mounted for longitudinal sliding movement in said slot in the base. said downwardly projecting portion having means on; the lower end thereof to hold the front end of the arm in engagement with the upper surface of said base, a latch engaging projection integral with the front end of said arm, latch means carried by the loom normally engaging said latch engaging projection on the arm, means controlling the latch means responsiveftfoa bobbin transfer operation for releasing the; arm from said latch means, spring means urging the arm rearwardly towards the lay uponthe arm being released from the latch means, a hook projection on the free rear end of said arm and being disposed immediately above the? lay as the lay moves in a beat-up stroke and at a point substantially midway of a beat-up stroke of the lay, means on said arm engageable by the lay as it continues in a beatup stroke for moving said arm with the lay and means on said arm adapted to engage said base for moving said arm in an upward arc with said continued movement of the lay whereby said filling ends will be ensnared by the hook on the rear end of the arm and are directed upwardly to be introduced to the thread-cutting temple to be severed thereby, and said means controlling the latch means for releasing the arm from the latch means upon a bobbin transfer operation also being operable to again move the latchmeans into position for engaging the latch engaging projection of said arm as the arm is again moved forwardly with a beat-up stroke ofthe lay.

7. In 'an automatic filling replenishing loom having abobbin transfer mechanism and also having an' oscillatable lay and also having a breast beam at the front of the loom and also having a thread-cutting temple supported on the breastbeam adjacent the selvage of the fabric being woven, an improved apparatus for ensnaring the filling ends which occur between the selvage of the fabric and the bobbin transfer mechanism for directing said filling ends to the thread-cutting temple comprising a base secured to the breast beam and having a longitudinally extending vertically disposed slot therein, a forwardly and rearwardly movable yarn ensnaring arm supported on the base and being provided with a downwardly projecting portion at the front end thereof mounted for longitudinal sliding movement in said slot in the base, said downwardly projecting portion having means on the lower end thereof to hold the front end, of the arm in engagement with the upper surface of said base, a latch engaging projection integral with the front end of said arm, latch means carried by the loom normally engaging said latch engaging projection on the arm, means controlling the latch means responsive to a bobbin transfer operation for releasing the arm from said latch means, spring means urging the arm rearwardly towards the lay upon the arm being released from the latch means, a hook projection on the free. rear end of said arm and being disposed immediately above the lay as the lay moves in a beat-up stroke and at a point substantially midway of a beat-up stroke of the lay, means on said arm engageable by the lay as it continues in a beatup stroke for moving said arm with the lay and means on said arm adapted to engage said base for moving said arm in an upward arc with said continued movement of the lay whereby said filling ends will be ensnared by the hook on the rear end of the arm and are directed upwardly to be introduced to the thread-cutting temple to be severed thereby, said base having an enlarged portion at the rear end thereof provided with a vertically extending slot therein through which the medial portion of said arm extends,

the last-named slot being closed at its upper end, and an upwardly projecting guide portion on said arm so arranged as to be disposed within said upwardly extending slot when the arm is released from said-latch means whereby said guide portion will engage the upper wall of said vertically extending slot when the arm is in a rearward position toflprevent said arm from being raised inadvertently in advance of the means on said arm engaging the base for moving said arm in an upward arc.

LEONARD L. HAWKINS,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,147,904 Stimpson July 27, 1915 1,261,620 Rhoades Apr. 2, 1918 1,340,207 Barrell May 18, 1920 2,182,103 Wiget Dec. 5, 1939 FOREIGN PATENTS Number Country Date 22,176 Great Britain of 1908 27,295 Great Britain of 1903

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