US2514083A - Signaling switch construction - Google Patents

Description

July 4, 1950 c. MILLER 2,514,083

STGNALTNC swITCH CONSTRUCTION Filed April 22, 1947 asheets-sheet 1 Mlm/M T ORNEY July 4, 1950 c. MILLER 2,514,083

STCNALING SWITCH CONSTRUCTION Filed April z2, 1947 2 Sheets-Sheet 2 INVENTOR ATT RNEY Patented July 4, 195() SIGNALING SW1-TCH CONSTRUCTION Christian Miller, Norwalk, Conn., assigner to Edwards & Company, Inc., Norwalk, Conn., a corporation of New York Application April 22, 1947, Serial No. 743,100

11 Claims.

This invention relates to hospital signalling switch construction, more particularly to a switch construction of the kind to be operated by a bed patient to actuate signals for the call of an attendant or the like.

One of the objects of this invention is to provide a practical and dependable signalling switch construction for the use of bed patients, and one that will reliably and eflicientl-y overcome the various and many structional, functionall and',

other disadvantages of heretofore known signalling switches made available to hospitals and the like for the use of bed patients. Another object is to provide a switch of the above mentioned character which may be dependably secured and held in place, as by attachment to the bed clothes, and thereby also reliably maintained in a position for the intended and desired actuation by the patient. Another object is to provide a switch constructionof the above mentioned character by which it will be possible to avoid the inconvenience and damage caused by the use, in present-day equipment, of safety pins in the endeavor to fasten a switch to the bed clothes, and to provide a construction which may be secured in position in such co-acting relationship of the various parts that ease and convenience of manual actuation by the patient are reliably achieved and maintained.

tients signalling switch that will be self-locking,

to insure the maintenance of the signals once the' patient'has actuated it, and in which convenient and fool-proof unlocking control means, for actuation by the answering attendant, are provided. Another object is to provide a switch construction of the just-mentioned character with unlocking means so constructed and so functioning as not to be confusing to the patient, and moreover to be substantially inoperable by, though accessible to, the patient.

Another object is to provide a hospital signalling switch of the above mentioned character that will be strong, durable and compact, yet well adapted for connection to, and to handle, multiconductor cables or cords. Another object is to provide a switch construction of the above mentioned character that will be economical manufacture, capable of ready assembly, and capable also of ease and facility of installation. Another object is in general to provide a hospital signalling switch of improved and more advantageous structure and operation, and other objects will be in part obvious or in part :pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicatedin the following claims.

In the accompanying drawing in which is shown a preferred embodiment of my invention:

Figure 1 is a top plan View of the complete hospital signalling switch;

Figure 2 is an end elevation as seen from the right in Figure 1;

Figure 3 is a vertical sectional view as seen along the line 3 3 of Figure 1, certain external parts being shown in elevation;

Figure 4 is a bottom elevation as seen with the bottom wall and certain related parts removed, y

being substantially a horizontal sectional view as seen along the line 4 4 of Figure 2;

Figure 5 is a horizontal sectional view as seen along the line 5 5 of Figure 2, being also and substantially a sectional View as seen along the line 5 5 of Figure 6;

Figure 6 is a vertical sectional view as seen along the line 6 6 of Figure 1;

Figure '7 is an elevation of a frame part or mounting element;

Figure 8 is an isometric view of a combination frame part; and

Figure 9 is an elevation or plan view of two locking elements.

Similar reference characters refer to similar parts throughout the several views of the drawing.

Referring first to Figures l, 2 and 3, I preferably provide a casing structure that is of substantial width and length and of relatively low height so that, when resting on the bed clothes or upper part of a bed or hospital patients equipment, it will have preferably a flatness of shape or form, thus making it less obtrusive in appearance and also contributing to its stability against being tipped over, and as is later pointed out I preferably make provision to give the complete switch structure a Very low center of gravity, thus to better insure maintenance of its upright position throughout the varying conditions of practical use. The casing structure comprises preferably a casing I0 having a top wall I I, opposed end walls I2 and I3 and opposed side walls I4 and I5, all preferably merging together in suitable curvatures somewhat as indicated in the drawing, with the end wall I3 preferably of smaller width and height than the opposite end wall I2. These curvatures are preferably such that they do not present any plane or at surface of 'any substantial area in order thereby not to suggest or present any face or wall which might be treated as a bottom wall by which to rest the device on a supporting surface. The side and end walls however terminate in an end peripheral edge IB which falls preferably substantially in a,plane, and co-acting therewith is a bottom plate generally indicated by the reference character I 'I and which is shaped to be received withinand secured to the casing I so as to present an under-face that is substantially in the plane of the edge I6.

Preferably the side and end walls are internally shaped to provide a substantially continuous lnternal ledge or shoulder I8 against which the bottom plate I'I rests and is secured by any suitable means such as screws 20 which are threaded into suitable enlargements or abutments 2| integrally formed with the shoulder I8, and illustratively three in number, as shown in Figure 4.

' The casing I0 is preferably made of any suitable moldable material or so-called plastic such as Bakelite or the like, and the conguration shown in the drawing and above described is one that lends itself readily to molding out of such materials. Moreover it is provided with a relatively large hole 22 (Figures 1 and 6) in the top wall II, illustratively square in shape, and with two relatively small and preferably round holes 24 and 25 in the side walls I4 and I5 respectively, being positioned near the junction with the top wall Il and preferably so that they and the top hole 22 are substantially aligned transversely of the structure. In molding the casing IIJ, I also shape and provide it with relatively thick shoulders or abutments that project from the internal face of the top wall I I, as indicated at 26, 21 and 28 (see Figures 4 and 5) which provide suitable plane surfaces which preferably fall in the plane of and are spaced only slightly downwardly from the top wall II, as viewed in Figure 3, thereby to provide rests or supports against which the arms 30, 3| and 32 of a frame plate 33 .respectively engage, to be detachably secured in place as by screws 34 which pass through suitable holes in these arms and are threaded into the shoulders or abutments ofthe casing wall II, being preferably threaded directly into the plastic, although they may be threaded into suitable threaded metal inserts molded into these abutments in any usual or known form and manner. Frame plate 33 has assembled to it a switching structure as is later described, thus to form a sub-assembly which, as a unit, may be inserted through the bottom open end of the casing IIl and secured in place as by the screws 34 above mentioned. To this switch structure any suitable number of insulated cable conductors are to be connected and the cable I preferably run into the interior of the casing ID through one of the walls of the latter, preferably the small end wall I3 in which is formed, during molding, a cut-out 35 (Figures 2 and 4), the cable being simply laid into the cut-out 35 which opens into the lower casing edge I6 and which is thereafter closed olf at its otherwise open end by the bottom plate structure I1 (Figure 2) which is secured in place by screws 20 (Figure 4) that are threaded into the molded abutments 2 I.

, The frame plate 33 is in the form of a heavy sheet metal stamping, having an outline and shapeas is better shown in Figure 7. Between the arms 3l and 32 the plate 33 is shaped to provide two spaced long extensions 332 and 33b and 4 to either side of the arm 30 are provided two similar, and similarly spaced, extensions 3?c and 33f, each extension being suitably shaped to provide a shoulder `S spaced inwardly from its extreme end, thus also leaving narrower end portions E which are later to serve as securing ears or lugs. The points from which these extensions extend from the plate 33 are preferably located equidistantly onva circle, and the plate 33 has, at its center, a round hole 3l whose axis is at the center of that circle, the metal of the plate 33 about the hole 31 being drawn downwardly as at 33g (Figure 6) to form a cylindrical bearing for slidably guiding a switch element 33 which is carried by and preferably integrally formed, as a single metal element, as of brass, with a stem 40 which, above the switch element 38, has a cylindrical part 4I that is dimensioned neatly to slide in the bearing 33g. The upper end of the stem 4I! has secured to it a button 42 preferably of non-conductive material Y and dimensioned and shaped to be loosely received in the hole 22 of the casing top wall II. The button 42 is thus substantially square in plan (Figure 1), may be made of any suitable plastic, and maybe secured to the stem 40 in any suitable way, preferably by providing the latter with a shouldered or lesser-diameter threaded end portion 4I]a which is threaded into a threaded hole in the button 42.

The extensions 33a, 33h, 33C and 33f, shown in development in Figure 7, are however bent at right angles to the plate 33 in directions away from the observer viewing Figure 7, and as is r better shown in Figures 5 and 6, thus bringing their four shoulders S into a plane parallel to the plate 33 and spaced downwardly therefrom,

to receive a member 43 (Figures 6 and 4) which;

is generally circular and is provided with four holes 43a, 43h, 43c and 43f through which these extensions are respectively received up to the shoulders S, whence the narrower end portions or ears E of the extensions are bent over to clamp the part 43 securely between the shoulders S and the bent-over ears E. As seen in Figure 6, the

part 43 is thus secured in depending relation,r

but rigidly, to the frame plate 33. If desired, arms 33c and 33f canbe spaced somewhat more widely apart than 33a and 33b to insure that assembly will be made in the correct way.

The part 43 is made of any suitable nonmetallic material, preferably a molded and cured resin or other plastic. It has a central hole 44 in which is slidably received the lower end of the stem 40 about which is a helical spring45whiclf1` Let it be assumed that the switch structure is' to control more than one electrical circuit, usually and illustratively in hospital bedside signalling systems, being ve in number; in the latter case I prefer to provide the switch structure with six conductor-connecting elements to which the six conductors of the cable may be electrically and mechanically connected, one of them being a conductor that is the common conductor ofall ve circuits. These connector elements, convenientlyin theform of screws 46 (Figure 4) are preferably exposed on the under face of the part 43, preferably equiangularly spaced about the circular area ofl that face, which is also preferably recessed asi at 41 one recess for each binding screw, to retain thev wire.

Each binding screw is threaded into a headed or shouldered metal bushing 48 (Figure 6) which is secured inany suitable wayl in a hole in the part. 43, there being one hole opening into each recess 41 for that purpose, andthe upper shouldered end of the bushing 48 serves to clamp in position the horizontal shank D of aspring sheet metal contact element which is` bent into a V- shape, as is indicated in Figure 6, to provide a springy and yieldable and vertically elongated contact5| that ispositioned inthe path of downward movementxof the bridging or switching ele.- ment` 38 above described. The shank part 50 is provided with a suitable hole through which the bushing 48 passes and the bushing is preferably knurled or roughed up on its external surface to make strong interlocking engagement with the material of the part 43 into the hole in which the bushing may be press-fitted.

As is better shown in Figure 6, the part 43 can be of relatively substantial thickness, and above the hole 44, and co-axially with the latter, it has a recess 52 for accommodating the spring 45 which is about the lower portion of the stem 4D, and grouped in a circle about its axis, the part 43 is provided with a series of recesses or wells 53, one for each of the six V-shaped contact elements 5|, each well 53 being of the same width as the sheet metal of the contact element 5| so that it cannot partake of rotary displacement about the axis of the bushing 48 which extends through the hole in the shank 50. Thereby also the contact elements 5| which project upwardly beyond the upper face of the part 43 are grouped in a circle about the axis of the switch stem 40 and are neatly positioned in the path of downward movement of the switch member 38. lf the spring contact arms 5| are all of the same length in their upward projection beyond the face of part 43, downward movement (Figure 6) of the stern 40, when the button 42 is depressed, brings the switch member 38 into wiping and self-cleaning engagement with all of the elements 5| and all of the circuits are closed,` the switch element 38 camming the members 5| radially outwardly against their spring action. If desired, however, and as later described, one or more of the contact elements 5|, other than that to which the "common is connected, may be of shorter length than the others so that they are not engaged and their circuits are not closed excepting when the stem 40 and its switch element 38 are given a slight additional depression. For purposes of illustration I have shown in Figure 6 one such other contact element, indicated at 5|`a other than the commonj which is shorter than the rest of the elements 5|.

I next provide for locking the stem 40 in depressed position against the spring 45, and preferably for locking it at a point in its downward movement that falls short of its maximum intended depression. Such locking means I preferably arrange to co-act with the enlarged stem part 4| and it preferably comprises two locking elements 55 and 56 shown in plan in Figure 9. These are constructed so that they may be easily formed by stamping out of sheet metal and they comprise somewhat elongated Shanks 55 and 561i` whichareat their-ends bent at right angles as at 5,5b and.. Elib (Figure 9, and see also Figure 6). Each has a widened rectangular` part 55c and 5Ec which at one edge orside are out out as at 55f and56f, at leastone. edge of the cutout, as at 55g and 56, being of a radius about equal to they radius of curvature of cylindrical stem enlargement 4|, and eachk being of preferably less than 180 in arcuate extent. The mouth of each of these cut-outs is equal to or greater than the diameter of the stem part 4l.

These two locking members 55, 58 rest upon the face of the frame plate 33, with the portions 55c and 58C overlying each other, their respective large areas insuring ample bearing surfaces for relative sliding movement therebetween, as well as between them and the upper face of the frame plate 33 and the under face of an auxiliary frame part generally indicate-d by the reference character 51 and better shown in perspective in Figure 8.

The frame part 5,'1 is a sheet metal stamping and has a central portion 5la from which depend side pieces 51h and 51C which are spaced apart by a distance equal to the equal widths of the overlying portions 55C and 56,c of the locking members 55` andy 56, and they are of a height which is a little greater than the thickness of these overlying parts.

The frame part 51 has also opposite end portions 5'lf and 5lg which have opposed and depending side parts which arer parallel to the side parts 51h and 5lc and spaced from each other by about the width of the Shanks 55e and 55a of the locking members. The latter, in their Shanks, have cut-out and bent downwardly, lugs 55h and 56h which are of a length to pass through trans versely elongated slots 33h and 33k (Figure 7) in the frame plate 33, when the two locking members are, in assembly, rested upon the frame plate 33 with the parts 55c and 56c interlocking withV each other. As shown in Fig-ure 8, the auxiliary frame part is provided with a suitable number of lugs L, preferably one for each side piece, and the frame plate 33 is provided with correspondingly dimensioned and spaced holes H into which the lugs, L are entered as the frame part 51 is brought over the superimposed locking members 55 and 56, whence the lugs L may be expanded or headed over on the under side or the Lframe plate 33 to complete the assembly of thesev two parts.

The overlying locking members 55 and 55 are thus neatly housed and guided for relative transverse movement to an extent permitted by the lengths of the slots 33h and 33k through which the lugs 55h and 56h of the two locking members project below the inner face of the frame plate 33. There these lugs are engaged by the two arms 58a and 58h of a helical spring 58 through which extends a headed stud or pin 65 (Figure '7) from the under side of the plate 33 to hold the spring assembled to it.

These spring arms, acting upon these lugs, yieldably hold the two locking devices in their position of maximum displacement away from each other, positions which bring the arcuate edges 55g and 55g closest to each other, thus to restrict the closed hole which the overlying parts 55c and 56L form in their overlying relation, the one closing off the side mouth of the other, and if -the upper portion of stem 4U (Figure 6) is n the path of this relative movement between the locking parts, the edges 55g and 56g can engage that stem 40, and upward movement of the stem,

of the longer contact elements 5|, one of Which is the common but is not in engagement with the shortest one or more of the remaining contact elements, such as the element 5|a. Accordingly all of the signal circuits excepting that to which the shortest contact or contacts (part 5|a, illustratively) is connected, are energized and their corresponding signals actuated. A subsequent additional manual depression of the button 42 bringsthe switch element 38 into contact with the element 5|a for as long a time as this additional depression is maintained, and the signal of tha circuit is correspondingly actuated.

If the two locking members 55 and 56 are both moved inwardly toward the axis of the stern 48 and against the action of the spring 60, the arcuate edges 55g and 56g are moved away from each other and as soon as they form a hole large enough for the stem enlargement 4| to enter it, the spring 45 urges the stem upwardly, the enlargement 4| enters that enlarged hole, and subsequent action of the spring arms 58*iL and 58b is ineffective to move the locking elements toward each other, for such movement is now blocked by the presence of the enlargement 4| in the paths of movement of the arcuate edges 55g and 56g. 'Ihe annular bearing flange 33g (Figure 6) serves as a stop by which the upward movement of the stem is limited when the laterally projecting switch element 38 engages the ange 33g. At the center of the frame part 51 is a hole 5lk thro-ugh which the upper part of the stem 40 passes co-axally, and preferably the hole can be large enough to accommodate stem enlargement 4| in its upward movement into its uppermost position, for in that way it is possible to make certain that the stem enlargement 4| bridges the gap or space between the plate 33 and the plate portion 5'|a to form an effective stop against which the spring arms 58a and 58D press the edge portions 55g and 56g of the locking elements and more particularly to form an effective stop against relative movement of the locking elements toward each other should manual pressure be applied to the bent end .portions 551 and 56h. 'I'he stem enlargement 4|, when in this uppermost position, thus blocks the locking elements against relative inward movement, the edges 55k and 56k (Figure 9) bearing against diametrically opposite portions of th stem enlargement 4|. f

The build-up frame and switch structure carried by it may thus be made up and assembled as a sub-unit or sub-assembly and is ready to be assembled to the casing I D. Before inserting it into casing I8, two flanged or shouldered buttons 6| and 62'(see Figure 6) are` inserted, from the inside, into the round holes 24 and 25 respectively that are positioned in the casing side Walls I4 and l5 at such respective points that, when the frame arms 30, 3| and 32 (Figures 4 and 5) rest against the shoulders 26, 21 and 28 respectively and the screws 34 arel putin place, the inner anged or headed ends of the buttons 6| and 62 are respectively juxtaposed to the bent ends 56b and 55b of the locking members 56 and 55, andthe button 42 is projected into thehole 22 in the casing top Wall f Thep'arts are so. proportioned that, with the' locking members 55j and=56 held in outermost positionyia position. which they occupy when the stem enlargementy 4|- is in uppermost position as` above described, ther-spacing between the bent ends 55h and; 55b from the respective casing side walls is materially greater than the axiallength of the heads or flanges of the buttons but not greaterthan the Vaxial length ofthe button Shanks, and hence the latter cannot fall out ofV place. As indicated in the drawing, the buttons are relatively small and inconspicuous compared tothe large and upwardly projecting top buttonA 42. Accordingly the patient, to whom the signalling switch structure is' allocated, actuates the button 42 inthe top wall of the casing by depress-- ing it against the action of spring 45.

When-the button 4271s depressed sufficiently to bring the upper shoulder end of the stem part 4| below the upper face of the frame plate 33 (Figure 6) ,the switching element 38 engages all of the longer contacts 5| and both locking elements 55 and 5G aresnapped outwardly away from each other under the action of the'spring arms 58a and' 58h as abovedescribed, locking the switch member 38 in the above described position of contact with the longercontacts 5|. The bent ends 561 and 55b of the locking parts move outwardly (Figure 6)v by respective distances just about equall to the difference in the radii of theparts 4| and 40, the arcuate edge portions 55g and 56g of the locking'mernbers engaging the upper stem part 40 to limit the outward movement of the locking parts. The latter movements, by the engagement-of the bent parts 55b and 56b with the buttons |52 and 6|, project the latter outwardly and laterally of the casing side walls |4 and |5, the spacing between the bent ends from the respective casing side walls being just about sui'licient to accommodate the heads or anges of the buttons which are thereafter held in projected position-s through the action of the spring arms 58a and 58b upon the two locking parts.

The signal circuits closed by the now locked engagement of-switch member 38 with the longer contacts 5| remain actuated or energized, but should the' patient desire to actuate, usually repeatedly, an additional signalling device, usually audible such as a buzzer, the patient need only depress the button 42 to the additional extent above described, thus closing an additional signalling circuit atthe shorter contactspring 5|a (Figure 6). Such additional actuation cannot and 'does' not affect the locking action above described-sol that cessation, of such additional orsupplernental actuation'of the button42 does' not interfere with the continued maintenance of the closure of theother signalling circuits at the longer contact springs 5|. When the attendant respondsv to the call,v the small side buttons 6| and82 stand projected laterally from the side walls 'of the casing and the attendant presses both of them inwardly to cause the locking parts to release the stern part 4| which, under the ac` tion of spring 45, moves upwardly with its related parts, interrupting all of the circuits and now projecting the top button 42 upwardly beyond the casing; the bent ends 55b andab of the locking members move inwardly asabove described, making ineiectual any possible manipulation-of either or both of the buttons 6| and 52 so that thereafter, should the patient again call,v the only part available for effective signalling actuationv is the button 42.4

The bottom plate Il (Figures 2, 3 and 6) is preferablylof composite construction, and preferably comprises a sheet 65 of a dense or heavy metal such as lead or leadalloy,'being of 'sufficient thickness and expanse and hence of weight relative to the remaining parts of the assembled construction as to very materially lower the center of gravity, 'as viewed in Figures 3 an'd and bringit into orasnearasp-ossible to a horizontal plane in or adjacent the lower end of thecasing l0, and preferably also it is Vso distributed that the center of gravity falls in or close tothe vertical axis of the button 42. The structure is thus given a great inherent stability against tipping over, thus to vcoac't to Ymaintain it upright when its bottom face rests upon an irregular or slanting portion Aof the bed, bed clothes or other parts. Preferably the'under face of the lead plate 55 has secured to it, as by an adhesive, a sheet 66 of friction'material such Aas relatively soft rubber, Apreferably rubber 'presenting an external irregular or roughened surface somewhat like sponge rubber, thus giving it good resistance to sliding out of desired location, particularly when it is positioned upon a part that slants or inclines.

It has been found in past practice that it is frequently desirable to secure the signalling switch construction to the bed clothes and heretofore resort has been had to the use of ,pins and safety vpins by which the flexible cable or cord extending from the switch structure is pinned to the sheets, blankets or the like. Such practices have been found to cause considerable damage to lthe sheeting, but according to my invention the above described features of low center of gravity, coupled with relatively large iiat expanseoi .bottom surface of Vthe structure, and also the nonslip feature of such under surface, can in large measure serve to avoid the need of using such damage-causing devices as safety pins. However circumstances of usemay arise where a positive fastening of the signalling device is desired and in such case I may provide in the bottom plate structure I1 a gripping device by which a suitable fold of the sheeting, blanket or the like may be dependably and detachably engaged, and thatfdevice I preferably arrange to be accommodated within or under that portion of the casing that narrows-down both in height and width, such as the right-hand portion in Figures l and 3 which terminates in the end wall i3 where the iiexible cable enters through the cutout or slot 35 (Figures l, 2 `and 3). As is-better shown-in Figure 3, I may thus utilize certain of Athe internal space to the right of the switching mechanism, more particularly to the rightofthe solid dielectric member 43.

The vgripping device preferably comprises a somewhat elongated plate part 6l which inclines downwardly from an internal upper point Aclosely adjacent Ythe part 43 to a point at the inside face ofthe end wall I3 andclosely adjacent the bottom edge thereof, and in cross-section it is preferably Ushapcd, having tapered side walls 68 and 69 (Figures 3 and a) which `are suitably apertured to support a pin 'll by which a clamping lever '12,preferablyof sheet metal, ispivoted, the yclamping 'lever having suitable side flanges or ears 'i3 and la through which the pin lllextends. A spring 'l5 extends about the 'pin 1I and has its end arms extending respectively against the plate part 61 and against the lever part 12 to vstrongly bias :the lever 1.2 in counterclockwise direction as viewed `in Figure V3. At its right-:hand end the lever 12 issuitablysshaped,

as by appropriately shaping the iianges 13 and 14, to provide suitable teeth ll which, by the spring 15, are pressed upwardly (Figure 3) against the lowermost portion of the inclined platepart y'l which, in any suitable manner, as by appropriately stamping or shaping the sheet metal, may be provided with companion teeth 18 (Figure Y3) to coact with the teeth il.

InA normal position and with no material or other part interposed between the companion gripping jaws or their teeth, the spring 'l5 holds the parts in about the position shown in Figure 3 in which the at plate-like portion of the lever l2 falls in a plane parallel to the plane of the bottom edge of the casing l0 or in the general horizontal plane of the bottom plate Il, thus to present and maintain a substantial closure of what is in eiiect a tapered upwardly extending recess projecting into the interior of the casing I0. The bottom plate structure thus presents no such irregularities or projecting parts as would catch on the bed clothes or the like or as would mar a finished furniture surface if the device were rested thereon, or as might cause injury to the ngers or hands in handling the device, and this is of advantage where the device is used asabove described, namely, without having to place reliance upon the gripping or clamping device.

However, it will be noted that the handle portion vof vthe lever 12, namely, that portion to the left of the pin H in Figure 3, remains juxtaposed to and spaced from that portion of the inclined plate part E1 that is of greatest projection inwardly into the interior space of the casing lo, and hence when it is desired to bring the clamping device'into action, a suitable nger pressure is applied to the lever 72, in an upward direction in Figure 3, and the lever 'i2 responds only when that pressure is `applied to the left of the pin 1I,thus making the device simple and foolproof to manipulate. When lever l2 is so depressed to swing it in clockwise direction, its right-handend with the teeth 'Il is projected well below 'the plane ofthe bottom edge of the casing I0 and below the bottom edge of the narrow end wall I3 which thus coacts to guide a suitable fold of the Vmaterial such as a sheet or a blanket, into the'opened gripping device which may then be released to let the strong spring 'l5 clamp and grip the material 4between the companion grip* ping jaws or teeth l1 and 18, the gripping action being aided by the distortion of the fold of material into a substantially U-shaped cross-section as the jaw endl of the lever 12 presses it upwardly in Figure 3 into the shallow end of the tapered recess, the r'lever structure 1,2, or its jaw end, .being preferably made of appropriately lesser width thanthe spacing between the parallel side wall parts 68 and .59 to permit this action to take place, particularly with respect to thinner cloth material such as sheeting. When thus clamped to the bedclothes or the like, the above described low center of gravity of the complete switching structure contributes to the stability of the device against being easily turned over and thus coacts to lessen the strain and burden to which the clamping device itself may be subjected in having to hold the switch structure in position against the varying conditions inherent in the use'of` the device.

The various wall parts that form the recess of varying depth in which the clamping lever 'l2 functions may .be easily formed, as by stamping, in the sheet'metal of which the bottom plate I? maybe formed or constructed, and if it is desired to utilize a sheetmetal such as sheet iron, the wall parts may be so drawn or stamped out of such material to form also a plate 16 (Figures 3 and 6) whose periphery is shaped suitably to rest against the ledge I6 (Figure 4) that extends peripherally in the bottom edges of the side walls, and to the under side of such a bottom plate element 16, the plate part 65 of lead or other dense and heavy metal, may adjoin or be secured in any suitable manner, to form a unitary bottom plate structure, with the friction material 66 in turn secured to the under-face of the lead plate part 65, thus to make up the bottom plate I1 of which the just described features of construction and assembly are illustrative. Where the bottom plate I1 is built up in this manner, the lead plate part 65 and the friction material 66 are cut away throughout the area of the tapered depression or recess outlined by the side wall parts 68 and 69 (Figure 4) and the end wall 'I0 adjoining them at one end.

It will thus be seen that there has been provided in this invention a signalling switch construction in which the several objects above set forth, together with many thoroughly practical advantages, are successfully achieved. The construction is compact, neat in appearance, and of fool-proof construction and action. It can be easily assembled and can be installed with convenience and facility. In this latter connection it might be noted that, as is better seen in Figure 3, the downwardly and outwardly inclined wall 61,'at its lower-most end, closes oi the slot 35 to coact with the iwalls of the latter in neatly holding in place that portion of the flexible and usually rubber covered cable that enters the closed casing, and desirably the parts are-so proportioned that a suitable clamping action on the cable or on a rubber bushing surrounding it can take place, and for that purpose appropriate portions of the end wall I3 may be molded, throughout the upper arcuate regions of the slot 35, t provide a relatively large expanse of arcuate or curved surface 35a (Figure 3) against which the cable can be clamped or pressed by the portion 61 of the bottom plate, the two screws 20 (Figure 4), one on each side of the resultant,

clamping structure, insuring secure and strong clamping action of these parts. Moreover the inclined wall portion 61 forms a guide and a rest for the inner end of the cable and its sheath,

from which the individual insulated conductorsillustratively six in number, may be fanned out for individual connection to and .by the binding screws 46 (Figure 4), some of them passing conveniently to the left of wall 68 and the dielectric switch base 43 and Vothers passing to the right `of I Wall 6B and the base'y 43, as they pass on vtheir way to the more remote and laterally distributed binding screws of which some are to the left of the vertical axis in Figure 4 and others are tothe right. These conductors are easily so fanned'out and so connected with the bottom plate l1 removed, the cable simply resting against the arcuate Walls of the slot 35, and when the bottom plate Il is put in place and secured by the screws 20, the anchorage or clamping of the cable as above described is completed, and any disturbset forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. A hospital-bed type of switch comprising a casing having opposed side walls with apertures therein and having a top wall with an aperture, a spring-biased manually-depressible actuator projectible externally of the casing and by way of said aperture, manual actuators slidably carried by said opposed side walls and in said apertures, switching mechanism within said casing and operable in one direction in response to depression of said actuator and having locking means operating in response to such depression to hold said switching mechanism in operated position, said locking means having two operating members to effect release thereof and positioned in respective juxtaposition to said manual actuators in the opposed side walls of said casing for actuation thereby from the exterior of said casing.

2. A switch as claimed in claim 1 in which said manual actuators are in the form of headed elements inserted into said apertures from the inside of said casing whereby said two operating members hold them against inward movement out of their respective apertures.

3. A switch as claimed in claim l in which said two operating members are provided with means operating in response to depression of said actuator toproject them outwardly away from each other and thereby eiect outward movement of said manual operators on opposed sides of the casing to position them for manual actuation when release of said locking means is to be eiected.

4. A switch construction comprising a casing open at its bottom and having an apertured top wall and opposed apertured side walls, a frame insertable into said casing and having a portion substantially parallel to the top wall and provided with transverse slideways having therein two coacting locking means for sliding toward or away from each other, said locking means having manual actuators respectively exposed through the apertures in said opposed side walls, said frame carrying switching mechanism having an operator movable crosswise of the paths of sliding movement of said two locking means to be lock- ,ingly engaged by the latter upon movement in one direction, said operator having a manual actuator exposed through an aperture in said top wall for manual actuation to move said operator in said one direction to actuate said switch mechanism and to be engaged in locking relation by said two locking means to hold the switch mechanism in actuated condition.

5. A switch as claimed in claim 4 in which said switching mechanism comprises a carrier insulatingly supporting a plurality of switch contacts grouped about the axis of said operator and providing a sliding bearing for the latter, said operator having conductive means movable in response thereto to engage said switch contacts.

6. A switch as claimed in claim 4 in which said switching mechanism comprises a carrier insulatingly supporting a plurality of switch contacts grouped about the axis of said operator and providing a sliding bearing for the latter, said operator having conductive means movable in response thereto to engage said switch contacts, one of said switch contacts being of diiferent length than the rest and thereby requiring an additional movement of said operatorl beyond the locking position to eifect engagement therewith.

v7. A switch construction comprising a casing structure having therein a sub-assembly comprising a frame carrying switching mechanism having an operator movable to actuate said switching mechanism in one direction andl locking means movable transversely of the path of movement of said operator and to lock the latter in response to movement thereof in said one direction, said locking means comprising two substantially hook-shaped locking members engaging said operator from opposite sides thereof and having means biasing them into engagement therewith, said operator having a stepped portion into which said hook-shaped locking members enter, said locking members terminating adjacent opposed side wall portions of the casing, and two actuators carried by the latter for operating said locking members in opposite directions from the exterior of the casing.

8. A switch construction comprising a casing structure having therein a sub-assembly comprising a frame carrying switching mechanism having an operator movable to actuate said switching mechanism in one direction and locking means movable transversely of the path of movement of said operator and to lock the latter in response to movement thereof in said one direction, said locking means comprising two substantially hook-shaped locking members engaging said operator from opposite sides thereof and having means biasing them into engagement therewith, said operator having a stepped portion into which said hook-shaped locking members enter, said locking members terminating adjacent opposed side wall portions of the casing, said opposed side wall portions having externally operable actuators to which said locking members are respectively interrelated upon assembly of said sub-assembly to said casing to effect operation thereof from the exterior of the casing.

9. A hospital-bed type of signalling switch comprising a casing structure with a bottom and being of substantial width and length and of relatively low height and thereby having a high factor of stability, said casing structure having a top wall with an aperture from which is projectable an actuator that is manually depressible in a direction toward the bottom, thereby to lessen disturbance, by actuation, of the stability factor of the device, said casing containing switching mechanism operable in one direction in response to depression of said actuator with locking means operating in response to such operation to hold said switching mechanism in operated position, said locking means comprising a plurality of locking members all of which effect locking or holding action upon said switching mechanism, said casing having laterally projecting therefrom a plurality of inwardly movable release actuators, one for each locking member, whereby release of said switch mechanism from operated position can be effected only by inward pressing of all of said release actuators.

l0. A hospital-bed type of signalling switch comprising a casing of substantial width and length and of relatively low height and thereby having a high factor of stability and having switching mechanism therein with manual actuator exposed from a wall of said casing and movable for signalling actuation of said switching mechanism in a direction having little disturbing effect upon the factor of stability, with locking means responsive to said signalling actuation for holding said mechanism in actuated condition, and a plurality of manual actuators movably carried by said casing for controlling unlocking actuation of said locking means whereby all of said plurality of actuators must be actuated to effect release of the switching mechanism from signalling position.

11. A hospital switch as claimed in claim 10 provided with means responsive to actuation of the switching mechanism in signalling direction for positively moving said plurality of manual actuators to respective positions of projection. from said casing yand thereby condition them for manual actuation in lock-releasing direction.

CHRISTIAN MILLER.

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

UNITED STATES PATENTS Number Name Date 780,860 Brusseau Jan. 24, 1905 333,317 Geisenhoener Oct. 16, 1906

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