US2160718A - Detector bar - Google Patents

Description

C. D. BROWN DETECTOR BAR May 3o, 1939.

Filed Nov. 9, 1938 a :nimm

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Patented May 30, 1939 UNITED STATES PATENT OFFICE Draper Corporation, poration of Maine Hopedale, Mass., a cor- Application November 9, 1938, Serial No. 239,665

3 Claims.

The present invention pertains to electric Warp stop motions for looms and more particularly relates to the detector bars of such stop motions.

Electric warp stop motions of the type to which my invention applies commonly include a plurality of parallel detector bars which extend widthwise of the loom across the warp sheet and which are located within slots or openings in drop wires. Each of such detector bars comprises a pair of contact bars o-ne of which has a channel in its upper edge and the other of which is fixed in said channel but provided with an upper Contact edge located above the top edge of the channelled contact bar. The two contact bars are insulated from each other and form the terminals of an electric circuit which is normally open but which is adapted to be closed by any one of the drop wires. The drop wires are supported by the warp threads and normally contact only the channelled contact bar. When any warp thread breaks, its corresponding drop wire falls into engagement with aforesaid upper contact edge, thereby closing the electric circuit.

Prior to the present invention, the detector bar slots in drop wires for use with electric warp stop motions were provided with an inclined edge, usually at the top of the slot, for causing a drop wire to move laterally as it falls. This lateral movement of the dropwire is found to be necessary to insure good electrical contact between the drop wire and both of the contact bars. In drop wires for use with mechanical warp stop motions, the aforesaid slots usually have straight sides and symmetrically rounded tops. It is desirable that electric warp stop motions be capable of operating with drop wires wherein the detector bar slots have rounded tops. This is because such drop wires are cheaper to manufacture and easier to finish properly, because of the expense and inconvenience of buying and using two .different types of drop wires in mills where both types of Warp stop motion are used, and for other reasons which need not be enumerated herein.

It is accordingly a principal object of the present invention to provide a detector bar for electric warp stop motions which detector bar shall comprise a channelled contact bar and a second contact bar xed in and insulated from the channelled bar, as aforesaid, but which second contact bar shall have a horizontal upper contact edge which is offset toward one side of the detector bar, whereby such detector bar may be used with drop wires of the aforesaid type wherein the detector bar slots have rounded tops.

The foregoing and other objects of the invention are accomplished in the construction illustrated on the accompanying drawing, of which:

Fig. 1 is a view in cross-section ofv an electric warp stop motion including the preferred embodiment of my improved detector bars;

Fig. 2 is a detail View, in cross-section, and to a larger scale, showing a drop wire and one of said preferred detector bars; and

Fig. 3 is a view similar to Fig. 2 but showing a modied form of my improved detector bar.

The warp stop motion shown on the drawing includes suitable supporting brackets, such as end bracket I, adapted to be fixed to a loom frame, not shown. One such end bracket is provided at each side of the loom, the brackets supporting the warp support members 2 and 3 which extend widthwise of the loom. Additional members Il, i extending between the brackets may be provided, for further supporting the warp sheet and for separating the various rows or banks of drop wires. The particular end bracket I shown is of two-piece construction, the lower piece being xed and the upper piece 5 being supported on vertically adjustable studs 6. The upper piece 5 is provided with slots or the like for receiving the ends of the detector bars hereinafter described, and a cap 'I is secured to the piece 5 by nuts 8 on the studs 6, to thereby hold the detector bars in said slots.

The warp stop motion as thus far described in detail is not of the present invention and may be of any suitable usual construction, my invention pertaining to the detector bars indicated generally at 9, 9 on Fig. l. The particular stop motion shown is of so-called four-bank construction in that it has four parallel detector bars for receiving four rows of drop wires I. Each of the drop wires is a sheet metal device having an opening II for receiving a warp thread W (see Fig. 2) and a slot I2 for receiving one of the detector bars. The drop wires operate in the usual manner in that each drop wire is normally supported by a warp thread but falls and engages the detector bar in a manner to complete an electrical circuit when a warp thread breaks. The drop wires Il! are of a type heretofore used only in mechanical Warp stop motions, the tops I3 of slots I2 being symmetrically rounded.

Each detector bar is of novel construction and consists of a contact bar I4 and a contact bar I5, which contact bars are insulated from each other. The contact bar I4 consists of side walls I6 and I 'l and a bottom portion I3 forming a channel which is open at its top. In other words, the

bar I4 extends horizontally across the loom and has a channel in its upper edge. This bar may be constructed in any suitable manner, but in the embodiment shown on Figs. 1 and 2 of the drawing the walls I 6 and Il are flat strips of metal which are spaced by and welded to a separate metal strip which constitutes the bottom portion I8. In this embodiment, the walls I6 and I'I are of rectangular cross-section and are positioned in vertical planes, whereby both the side faces of the detector bar and the sides of the channel are substantially vertical.

The contact bar I consists of a relatively thin strip of metal which is fixed in and extends generally horizontally along the aforesaid channel in contact bar I4. The contact bar I5 may be xed in said channel in any suitable manner, but is insulated from the contact bar I4 as by insulating material I9. The bar I5 is bent along a longitudinal line, to provide a lower portion (i. e., the portion in said channel) which is positioned in a vertical plane, and a top contact edge 2G which is off-set to one side of the vertical axis of the detector bar. As shown more clearly on Fig. 2, the top edge 20, which extends horizontally across the loom, is located above and vertically over the top of wa'll I6. As thus located, the edge 2G is appreciably nearer to the vertical plane containing one side face of the detector bar than to the corresponding plane containing the other side face thereof. The edge 20 is, however, located between said planes in order to prevent its engaging the side of the slots I?. in the drop wires.

The aforesaid off-setting of the contact edge 2S results in the eflicient cooperation of the detector bar with drop wires having rounded tops I3. More specifically, it will be seen that if the edge 20 were centrally located with respect to the side faces of the detector bar, a fallen drop wire would balance on such edge and would not make good electrical contact with the contact bar I4. However, being thus off-set, the edge 20 will first engage a falling drop wire at some point such as point 2I (Fig. 2) on the round I3, whereupon the top of the drop wire will move laterally toward the right on Fig. 2 until the wire contacts the wall I1.

A modified construction is shown on Fig. 3 of the drawing, this construction including, however, the same drop wire I0 having slot I2 and rounded top I3 shown in Figs. 1 and 2. In this construction, the detector bar includes a Contact bar having side walls 22 and 23 and a bottom portion 24. The side walls 22 and 23 are formed from strips of metal which are of triangular cross-section and which are so related that the side faces of the Contact bar as a whole are vertical but the sides of the channel in such bar are parallel and inclined to the vertical. Y

The embodiment of Fig. 3 further includes a contact bar 25 which is fixed in the channel in the above-described contact bar and which consists simply of a thin, flat strip of metal. The contact bar 25 is fixed in a plane which is parallel to the side Walls of said channel, and is insulated by insulating material 26. As thus constructed, while the contact bar 25 is at, the upper horizontal edge 21 thereof is off-set to substantially the same relative position as contact edge 20 in the embodiment previously described. It will be seen that the detector bar shown on Fig. 3 will operate in the same manner as the detector bar 9. Neither of the embodiments of detector bar is limited to use with the particular drop wires shown.

Having fully disclosed the preferred embodiment of A'my invention, I claim:

l. An electric warp stop motion detector bar comprising a pair of horizontal contact bars, one of said contact bars having side walls and a bottom portion forming a channel which is open at its top, the side faces of said contact bar being substantially vertical, and the other of said contact bars consisting of a relatively thin strip of metal fixed in said channel and insulated froml the rst said contact bar, said other contact bar having a horizontal upper edge located above and vertically over one of said side Walls but between the planes of said side faces.

2. An electric warp stop motion detector bar comprising a pair of horizontal contact bars, one of said contact bars having side walls and a bottom portion forming a channel which is open at its top, the side faces of both of said side walls being substantially vertical, and the other of said contact bars consisting of a relatively thin i strip of metal bent to provide a lower portion positioned within said channel parallel to said side walls and an upper edge portion located above and vertically over the top of one of said side walls, said other contact bar being insulated from the first said contact bar.

3. An electric warp stop motion detector bar comprising a pair of horizontal contact bars having insulating material therebetween, one of said contact bars havingside walls and a bottcm portion forming a channel which is open at its top, the sides of said channel being parallel and vertically inclined, and the other of said contact bars consisting of a flat strip of metal iixed in said channel in a plane parallel to said inclined sides, said strip having a horizontal top edge located vertically over the top of one of said side walls.

' CARL D. BROWN.

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