US2559715A - Compression-connecting terminal member - Google Patents

Description

July 10, 1951 E. L. EARLE EIAL 2,559,715

COMPRESSION-CONNECTING TERMINAL MEMBERS Filed Dec. 20, 1948 2 Sheets- Sheet 1 INVENTORS EDWIN L. EARLE RICHARD P. ARTHUR JOHN LBELLAMY ATTORNEY July 10, 1951 E. L. EARLE ETAL COMPRESSION-CONNECTING TERMINAL MEMBERS 2 Sheets-Sheet 2 Filed Dec. 20, 1948 Fla. 6

INSULATION EEEQH EIEIEEQ EI FIG. IOA

INSULATION 6 3 M m 7 b w 3 2 H I B I i m z i 4 9 m D a 2 I n 6m l o B 0 0 P 0 0 FIG. I I

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INVENTORS= EDWIN L. EARLE RICHARD P. ARTHUR JOHN I. BELLAMY ATTORNEY Patented .Iuly 10, 1951 COMPRESSION-CONNECTIN G TERMINAL MEMBER Edwin L. Earle and Richard P. Arthur, Chicago, and John I. Bellamy, Wheaton, 111., assignors to Kellogg Switchboard and Supply Company, Chicago, 111., a corporation of Illinois Application December 20, 1948, Serial No. 66,172

8 Claims.

This invention relates to compression-connecting terminal members. Its general object is to provide improved compression-connecting terminal apparatus for detachably connecting a number of conductors to terminal points.

A specific object is to provide compressionconnecting terminal apparatus for detachably interconnecting a number of electrical conductors.

- A further specific object is to provide compression-connecting terminal apparatus for detachably connecting a number of wires to common bare wire multiples to effect electrical connection therebetween.

The invention is of great utility, particularly where employed with automatic telephone switchboards of automatic telephone systems to connect conductors terminating on the frame structure with conductors leading to equipment. mounted in drawer-like arrangements within the frame.

'Two embodiments are disclosed which differ principally in the application of apparatus and the structural modifications therefor.

' Features of the invention include the following:

1. The connecting terminal members are of individual' spring form which insures adequate contact pressure when they are compressed in final assembly.

2. A rubbing engagement occurs between re- 3 spective opposed terminal contact portions when the spring terminal members are being compressed into clamped assembly, which provides assembled contacts free of dirt and obstruction.

3. The individual spring terminal members are provided with a relatively short offset portion at one end which suffices to retain the member in position along its terminal retaining strip and which permits its ready removal and replacement.

4. Fanning-strip holes are provided in each terminal-retaining strip to relieve terminal strain and to retain entering conductors in a position which prevents their acute bending and breakage.

Of the drawings, Figs. 1 to 10 show the construction of one embodiment of the improved compression-connecting terminal apparatus employed to interconnect electrical conductors, and Figs. 11 to 14, show certain of the structure of Figs. 1 to 10 modified for employment with bus bars.

Figs. 1 and 2 show respectively a plan and a front side view of the terminal connecting assembly.

Figs. 3 to show respectively a right end view taken along lines 3-3 of Fig. 1, and cross-sec- 2 tional views taken along lines 4-4 and 5-5 of Fig. 1.

Figs. 6 to 8, and 10, and their associated auxiliary views, show certain of the parts included within the terminal assembly.

' Fig. 9 shows a cross-sectional view taken along lines 9-9 of Fig. 8. 1 a

Fig. 11 shows a top view of the assembly modified according to the principles of the second embodiment.

Figs. 12 and 13 are respectively, cross-sectional views taken along lines [2-H and 13-43 of Fig. 11.

Figs. 14 and 14A show respectively a side and an end View of the terminal assembly retaining clip.

- Detail-ed description In the first embodiment shown in Figs. 1 150.10, angle bar A serves as a supporting and lower clamping member for the detachable compression-connecting terminal apparatus mounted thereon.

Referring now to Figs. 1 to 5, there the terminal apparatus is shown to include opposed upper and lower terminal- retaining strips 3 and 4, and the associated terminal members I5 thereof, similar upper and lower insulating and spacing members 2, and lower frame insulating member 5, all suitably clamped together between upper channel bar! and lower angle bar A by studs 6 passing through provided openings in the parts and threaded into angle bar A.

The parts of the compression-connecting terminal apparatus shown in Figs. 1 to 5, will now be described with particular reference to Figs. 6 to 10.

The upper channel bar-l extends across the assembly and is a relatively thick and rigid member which provides uniform clamping pressure throughout its length to parts clamped therebetween and bar A. Similar openings 1 of the illustrated keyhole shape are provided in the web of bar I at the ends thereof, and at intermediate points between the ends, through which clamping studs 8 pass to retain the parts uniformly compressed in clamped assembly. -The keyhole shaped openings 1 are larger at one end than the heads of studs 6 and are smaller than such heads at the other end. The shape of openings 1 permits bar I to be assembled with the other parts loosely in place, with the heads of studs 6 passing through the enlarged portion of the openings 1 in bar I. The stud heads serve to retain the bar in place when it is moved longitudinallya controlled distance to bring the smaller portion of the openings 1 thereunder. This assembling arrangement is advantageous in facilitating assembly and in permitting a final inspection of the parts for alignment, etc., before studs 6 are finally tightened.

The clamping studs 6 are similar and are best illustrated in Fig. 4, where they are shown to be capped at one end by an enlarged slotted head portion and threaded at the other end for engagement with tapped openings in angle bar .A. The upper body portion of the studs tapers to a neck portion of lesser diameter to facilitate the aforesaid movement of :bar I, which brings the small portion of openings 1 under the heads of the studs and into engagement with such neck portion.

Figs. 1 to show similar upper and lower spacing and insulating members 2 (Fig. 7) lying flush with the outer surface .of their respective terminal- retaining strips 3 and 4 at a central portion thereof between offset terminal portions I33 and d1 of terminal members P5 of the .strips.

Eachsu'ch member 2 is relatively narrow .permitting it to lie flush against the noted central mention of its respective terminal strip .(3 or i) whereupon the pressure of the associated clamp bar 01 A) is exerted through such member against the .centralportion of such terminal strip which is most desirable in view of the compressi-lcle terminal contact portions extending t-transversely of such central portion on the other side of such terminal strip. The restricted width :of each such :member 2 permits the terminal portions 1;! of the compressed terminal members 15 of the associated terminal strip to pass freely to the outside thereof and the thickness of such member 2 is suflicient to keep such ter minal portions .ll' well out of contact with the associated rclamp bar when terminal members is": are compressed thereby.

when the compression-connecting terminal apparatus is employed, as illustrated in Figs. 1 to .5, "to interconnect a number of external conductors 0, two similar subassemblies of terminalmetaining strips :3 and 4 and their respective associated iindividual spring terminal members iii, are clamped in overlapping relationship, with theiupper strip 3 in the position shown in Fig. 8 and the lower strip 4 rotated 180 about its lonzgitndinalaxis. The assembled position of strips and 4 zb-rings :the intermediate compressible contact portions .20 of the individual spring terminal-members 1:5 thereof into opposed spring- .engag ing relationship to thereby connect related conductors .C (see Fig. 3) terminating on the respective upper and lower terminal ends l6 which, as shown best in Fig. 1, extend from opposite sides of the assembly.

The :similar upper and lower terminal- retaining strips 3 and 4 are relatively wide and. thick sheet-like strips of suitable insulating material which :serve to retain individual spring terminal :members, generally designated as l5, transversely thereof in a row in the manner shown for one such terminal member in Fig. 9.

.Asshown in Fig. 8, generally rectangular openings 1:3 and I4 extend in opposed rows adjacent to opposite edges of strip 3 for receiving respective terminal members 15. Openings M are dimensioned to permit the respective offset conductor attachment portions 1'6 of terminal members 15 to pass therethrough during assembly and to receive angularly offsetting portions 19 there of, Openings B are dimensioned to permit the passage of respective offset portions IT during the assembly or removal of the terminal members and to permit the angular offsetting portions 18 thereof to freely pass therethrough when the associated terminal members [5 are compressed into final clamped assembly to thereby permit the desired spring action thereof.

Fig. 8 shows the relative position of openings [3 :and M with respect to the opposite edges of strip 3, and the small circular openings l2 located outwardly from and to one side of such openings I l. Openings 42, as shown in Figs. 1 and 3, provide .-a fanning strip arrangement for external conductors passing therethrough and connected to the adjacent attachment ends it of terminal members [5. Openings [2 function to relieve the strain between terminal attachment ends 16 and the conductors attached thereto and to prevent acute bends of such conductors ordinarily resulting in their breakage.

illhestud-receiving openings 8 and 9 in strips 3 :and 4 are slightly on center to stagger such strips in final assembly to thereby bring openings l2 outwardly from the overlapping terminal retaining strip to permit access of the associated conductors thereto. See Fi 3.

The similar individual spring terminal members 15 are punched and formed from suitable spring-sheet stock to the form illustrated in Fig. 9. Each terminal member 15 has a curved intermediate contact portion 28 and offsetting portions 1-8 'and [9 extending therefrom terminating respecfirmly in a short offset portion IT and a relatively long conductor attachment portion l6. Each offsetting portion 19 is short to limit the move- =ment of the associated assembled conductor attachment portion IE and each portion I8 is relatively long .to permit substantial movement of the associated end of the terminal member.

Terminal members 15 are assembled with their retaining strip 3 or 4 by first inserting offset conductor attachment portions 16 through respective strip openings id to the illustrated position of engagement with one side of the strip and by :then inserting offset portions I! through respective openings l3 which may be readily accomplished because of the resiliency of members 1'5. Offset portions [6 and i1 normally engaging one side of the strip cooperate with respective contact portions 20 engaging the other side of the strip to retain members l5 in position.

The individual spring terminals l5 may be assembled with retaining strips 3 or 4 by a stapling process or by forming the terminals in connected strip form in desired groups for strip handling, with the connecting portions subsequently severed after assembly with the retaining strip to provide individual terminal members.

Fig. 9 shows an individual spring terminal member 15 before it is compressed in final assembly, and Figs. 3 to 5 show two opposed ter- 'minal members '15 compressed in final assembly. it will be observed that certain of each contact portion 20 lies flush with the "contact surface of its retaining strip (3 or 4) to prevent movement of the adjacent terminal portion IE (the conductor attachment end) which lies flush with the opposite strip surface. The remainder of the curved contact portion 2% "is offset from the flush portion thereof and consequently from the :contaof surface of the strip to permit movement to such contact surface during the compression of the terminal member. Such movement is .permitted by the extending portion it freely passing through its opening i3 and by the narrowness of the associated spacing member 2, which provides an unobstructed path to offset portion I1 passing to the outside thereof. The movement of the compressed terminal is effected against its spring tension which insures uniform and adequate spring contact pressure throughout a clamped'assembly of compressed individual spring terminal members.

The conductor attachment offset portions iii are formed as illustrated and are relatively long to extend beyond the associated strip to serve as anattachment point for external conductors.

The offset portion ll of each member [5 is sufiiciently short to enable it to pass through openings..l3 with the opposite offset portion It in placeto permit terminal member removal and replacement, and in assembly do not extend laterally beyond the edge of their retaining strip.

The individual spring terminal members l5 are arranged in separated groups of ten along retaining strips 3 or 4 to permit the passage of the intermediate clamping studs 6, with the openings in the strips lying to either end of such terminal groups being designated by the numeral- H and not used in the structure of the arrangement permits frame wires to be brought out to accessible locations Where they are readily soldered to terminal portions iii of the respective terminal members [5 and in many instances the detachable arrangement permits bench wiring. After. the conductors to be connected are attached'to the respective terminal members (5 of .strips3and 4, the strips and other parts of the assembly are quickly and easily assembled.

In assembling the apparatus, clamping studs ,6 are first loosely threaded into angle bar A to approximately the same distance whereupon the parts of the assembly are assembled in overlying relationship on the upper surface of the bar with studs 6 passing through openings 8 and 9 in the parts. Openings 8 and 9 have a vertical dimension corresponding to the body portion of studs 6 to limit vertical movement of assembled parts 2 to 5. A similar dimension is provided longitudinally for openings 8, one of which is located at one end of each of such parts, to limit longitudinal movement thereof. Openings '9 are elongated longitudinally to permit ease of assembly. Parts 2 to 5 are assembled with the openings 8 thereof at the same end of the assembly to provide for correct alignment of the parts.

The parts of the assembly are assembled in the following order.

The frame insulating member 5 is first assembled directly upon the upper Surface of lower 4 and 3, with associated terminal members I5 in :place, are next assembled in that order, with strip 4 reversed with respect to strip 3 to bring "the contact sides of the strips adjacent to each other, and to provide that the contact portions 6 of the respective terminal members l5 thereof are in opposed engaging relationship.

An insulating and spacing member 2 is next assembled, whereupon upper channel bar I is assembled thereupon, with the heads of studs 6 passingthrough the enlarged portions of openings I therein. Channel I is then moved longitudinally to bring the'smaller portion of openings I under the stud heads and into engaging relationship with the neck portion of studs 6. The heads of studs 6 hold bar I and the underlying parts loosely in place to permit the previously noted visual inspection of the parts for alignment before studs 6 are finally tightened. The tightening of studs 6 completes the assembly with the opposed individual spring terminal members i5 compressed into spring-contacting engagement to effectively connect respective conductors attached thereto.

Second embodiment Referring now particularly to Figs. 11 to 14, the

second embodiment of the improved compression-connectin terminal apparatus will be described.

In general principle and structure, the second embodiment of the apparatus is similar to the first.

The principal difference between the structure of the first and second embodiments is that in the first embodiment two strips of opposed individual spring terminal members are compressed to detachably connect respective conductors terminating thereat, and in the second embodiment only one of such strips is employed with the individual spring terminal members thereof compressed into engaging relationship with intermediate portions of uniformly spaced bus bar multiples for effective detachable electrical connection therewith.

The modified compression-connecting terminal apparatus serves a highly useful function in detachably connecting various electrical units, relays, counters, etc., commonly mounted in overlying rows within switchboard frame structure, to bus bar multiples which are common to respective electrical units of the several rows.

The utility of the detachable connecting terminal apparatus lies in the fact that the electrical units of a row may be bench wired to respective individual terminal members of the apparatus which is readily clamped into efiective detachable electrical connection with the common bus bars.

The detachable feature of the apparatus is desirable in view of the compactness of modern switchboards in that it permits ready electrical connection in limited spaces and relatively inaccessible locations.

Fig. 11 shows a top view of an end portion of the modified compression-connecting terminal apparatus employed with bus bars B. Figs. 12 and 13 show in cross section an intermediate portion of a bus bar B clamped between a compressed individual spring terminal member l5 and the two underlying insulating members 2 to retain the bar in position and to establish effective detachable electrical connection between the bar and the terminal member.

In actual use a, series of relatively rigid frame channels D of the illustrated form extend horizontally across a frame structure at desired vertical locations to serve as lower clamping memhere for respective similar units of compressionconnecting terminal apparatus clamped thereto. For convenience only a portion of one unit of .sembly pass through such openings.

:such terminal apparatus .and a portion of its studs 3%; correspond to the locations of 'thestudreceiving openings '7, 8, 9 in the parts :of the terminal apparatus (Figs. ii to 8) and in final as- Studs 36 are threaded at the free end to receive the hexagonal retaining nuts 3i.

A fiat shelf-like bracket :38 of suitable insulating material issecured'by rivets 39 (Figs. .11 and 12) to the under surface of the lower leg of each channel bar D. Each member 38 extends across its associated bar D andserves to retain vertical spring terminal members I which are respectively compressed against the bus bars in final assembly. Two insulating members 2 are assembled between each channel bar D and .bus

.bars B to maintain the bars sufficiently out of contact with bars D.

The terminal-retaining strip 3 and associated individual spring terminal members 15, upper insulating member 2, and channel bar I are similar to the corresponding parts of the first embodiment and are assembled in that order and are retained in subassembly by similar retaining clips 4!.

Clips '4! are of the illustrated form (Figs. 14 and 14A) and in the noted subassembly snugly encompass channel bar i with the leg portions G2 passing through notches it of the underlying upper insulating member 2 (see Fig. 7) and through rectangular openings H in terminalretaining strip 5 (see Fig. 8) where they are :crimped on the under side of strip 3 to retain the parts in subassembly. Retaining-clips are employed at the ends of the subassembly and at intermediatepoints thereof between each group of ten individual spring terminal members 15. A circular opening is provided in the upper intermediate portion of each clip M to permit the passage of the upper portion of clamping studs 36 and the narrowed-portion of hexagonal retaining nuts 3? (Fig. 12).

The various electrical units oi a row are bench wired to the terminal portions 16 of the respective individual. spring terminal members 1'5 of a subassembly of compression-connecting terminal apparatus. The row of electrical units may then be secured in final position and readily connected to respective bus wires B by means of the compression-connecting terminal apparatus wired respectively to such units.

The wired subassexnbly cf compression-connecting terminal apparatus is readily placed in pcsitionon chanpel D with thecla-mpingstuds 33 passing through the previously described openings ('i, 8, and Q) of the parts. Hexagon retaining nuts Bl are loosely threaded on studs 55. At this point contact portions 2c of the individual spring terminal members 1 5 loosely engage respective bus bars B a visual inspection is made for alignment. The hexagon nuts 3i are finally tightened :and the individual spring termirrral members is are compressed against their respective bus bars Bas in the manner previously 8 described. The final :clampi-ng action .retains the bus bars B in position and establishes eiTective electrical connections between the :bus bars and the respective individual spring terminal members 4.5 and the electrical'units respectively wired thereto.

We claim:

1. An electrical device for detachably-connecting conductors to terminal points, said device comprising a sheet-like strip of insulating material andsimilar conducting spring members disposed transversely of the strip and comprising a .row extending along the strip, the said strip having pairs ofopenings therethrough for receiving said conducting members respectively, said openings comprising two rows extending along the strip respectively adjacent to opposite edges thereof, each said conducting member having a contact portion lying on one side of the strip and extending between the two openings of its pair, each said conducting member being retained 'in assembled position by outwardly extending offset portions lying in engaging relationship with the other side of the strip, the offset portions of any member being connected with the contactportion thereof by angularly disposed portions positioned within the respective openings of the assigned pair, one opening of each (said pair being relatively wide transversely of ithefstrip, the length of the associated oiiset portionof any conducting member being less than the said width, enabling any conducting member to be sprung for iinsertion therein and withdrawal therefrom while the other end of such member is in assembled relationship with the strip.

' 2. An electrical device for detachably connecting conductors to terminal points, said device comprising asheet-like strip of insulating material and similar conducting members disposed transversely of the strip and comprising a row extending along the strip, the said strip having pairs of openings therethrough for receivingsaid conducting members respectively, said'openings comprising two rows extending along the :strip respectively adjacent to opposite edges thereof at different distances from their respective edges, thereby providing both a short and wide margin at the edges of said strip, each said conducting member having a contact portion lying on one side of the strip and extending between the two openings of its pair, each said conducting mem her being retained in assembled position by outwardly extending offset portions lying in engaging'relationship with the other side of the strip, the onset portions of any member being connected with'the contact portion thereof by angularly disposed portions positioned within the .re- 'spective openings of the assigned ,pair, one such ofiset portion extending sufilciently beyond the wide margin edge of said strip to serve as an attachment point for an external conductor, the other offset portion terminating within the short margin of the strip.

3. An electrical device for detachably connecting conductors to terminal points, said device comprising :a sheet-like strip of insulating material and similar conducting members disposed transversely of the strip and comprising 'a .row extending along the strip, the said striphaving pairs of openings therethrcugh for receiving said conducting members respectively, said openings pomp-risin :two rows extending :along the strip respectively adjacent to opposite "edges thereof at different distances from their respective edges, thereby providing both :a short and wide margin at the edges of said strip, each said conducting member having a contact portion lying on one side of the strip and extending between the two openings of its pair, each said conducting member being retained in assembled position by outwardly extending offset portions lying in engaging relationship with the other side of the strip, the ofiset portions of any member being connected withthe contact portion thereof by angularly disposed portions positioned within the respective openings of the assigned pair, one such offset portion extending sufficiently beyond the wide margin edge of said strip to serve as :1. connecting point for an external conductor, said strip having a third row of openings therethrough 1ocated within said wide margin for receiving external conductors connected to said points.

4. An electrical device for detachably connecting conductors to terminal points, said device comprising a sheet-like strip of insulating material and similar conducting spring members disposed transversely of the strip and comprising a row extending along the strip, the said strip having pairs of openings therethrough for receiving said conducting members respectively, said openings comprising two rows extending along the strip respectively adjacent to opposite edges thereof, each said conducting member having a contact portion lying on one side of the strip and extending between the two openings of its pair, each said conducting member being retained in assembled position by outwardly extending offset portions lying in engaging relationship with the other side of the strip, the offset portions of any member being cormected with the contact portion thereof by angularly disposed portions positioned within the respective openings of the assigned pair, one said connecting portion of any conducting member being relatively short to limit movement of the associated end of the conducting member longitudinally of the opening, the other said connecting portion being relatively long to permit substantial movement of the associated end of the conducting member longitudinally of the opening, the said contact portion of any conducting member being formed to present a convex surface to the strip, and to an extent which normally maintains each of its said oifset portions substantially in contact with the associated side of the strip.

5. An electrical device for detachably connecting conductors to terminal points, said device comprising a sheet-like strip of insulating material and similar conducting spring members disposed transversely of the strip and comprising a row extending along the strip, the said strip having pairs of openings therethrough for receiving said conducting members respectively, said openings comprising two rows extending along the strip respectively adjacent to opposite edges thereof, each said conducting member having a contact portion lying on one side of the strip and extending between the two openings of its pair, each said conducting member being retained in assembled position by outwardly extending offset portions lying in engaging relationship with the other side of the strip, the offset portions of any member being connected with the contact portion thereof by angularly disposed portions posi tioned within the respective openings of the assigned pair, one said connecting portion of any conducting member being relatively short to limit movement of the associated end of the conducting member longitudinally of the opening, the other said connecting portion being relatively long to permit substantial movement of the associated end of the conducting member longitudinally of the opening, each conducting member having a form such that the part of the contact portion to which the longer of said angularly disposed portions is connected is held away from contact with said one side of said strip, whereby force must be applied against said contact portion to hex it to a position in which it lies fiat against said strip.

6. In combination, a group of first conducting members, a rigid support bar, means including a first overlying insulating strip interposed between the bar and said first conducting members for supporting them in overlying relationship to the bar and strip, said first conducting members extending transversely of the bar and strip and forming a row extending longitudinally thereof, a secondinsulating strip overlying the said bar, the first strip, and the first conducting members, second conducting members individually woven into the second insulating strip in overlying relationship to the first conducting members respectively, each said second conducting member having an intermediate contact portion lying on the under surface of the strip in engaging relationship with its underlying first conductor member, the end portions of each second conducting member lying in engaging relationship with the upper surface of the said second insulating strip, one said end portion of each second conducting member being adapted to terminate an external conductor, a comparatively narrow third insulating strip overlying the second insulating strip in contact therewith between the said end portions of the second conducting members, a rigid clamp strip overlying said third insulating strip, and means, including clamp rods passing through all said insulating strips and operatively engaging said support and clamp bars; for clamping the assembly together with sufficient force to maintain the said contact portions of the second conducting members in contact with their respective underlying first conducting members.

'7. In combination, a group of first conducting members, a rigidsupport bar, means including a first overlying insulating'strip interposed between the bar and said first conducting members for supporting them in overlying relationship to the bar and strip, said first conducting members extending transversely of the bar and strip and forming a row extending longitudinally thereof, a second insulating strip overlying the said bar, the first strip, and said first conducting members, second conducting members individually woven into the second insulating strip in overlying relationship to the first conducting members respectively, each said second conducting member having an intermediate contact portion lying on the under surface of the strip in engaging relationship with its underlying first conducting member, the end portions of each second conducting member lying in engaging relationship with the upper surface of the said second insulating strip, one said end portion of each second conducting member being adapted to terminate an external conductor, each said second conducting member being of spring material and being so formed that a large part of its contact portion lies substantially out of engagement with the adjacent surface of the associated insulating strip, requiring the application of substantial force to flex it to a position in which it lies fiat against its last said strip; a comparatively narrow third insulating strip overlying the second in- 11 sulating strip in contact therewith between the said end portions of the second conducting members, a rigid clamp strip overlying said third insulating strip, and means, including clamp rods passing through all said insulating strips and operatively engaging said support and clamp bars, for clamping the assembly together with sufiicient force to maintain the said contact portions of the second conducting members substantially flat against their said strip, to apply efiective spring contact force against their respective underlying first conducting members.

8. A combination as set forth in claim 7, wherein the said first insulating strip and said first conducting members are similar to the said second strip and associated conducting members.

EDWIN L. EARLE. RICHARD P. ARTHUR. JOHN I. BELLAMY.

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

UNITED STATES PATENTS Number Name Date 1,027,337 Holmes May 21, 1912 1,514,618 Ide Nov. 1, 1924 1,828,276 Beers Oct. 20, 1931 2,074,958 Chirelstein Mar. 23, 1937 2,279,824 Keefe Apr. 14, 1942 2,284,462 Williams May 26, 1942 2,433,358 Garberding Dec. 30, 1947

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