US2690877A - Fastening for railway rails - Google Patents

Description

s 5? 194 I J, R, SNYDER 2,690,877 FASTENING FOR RAILWAY RAILS Filed Sept. 3, 1948 2 Sheets-Sheet l J. R. SNYDER FASTENING FOR RAILWAY RAILS Filed Sept. 3, 1948 2 Sheets-Sheet 2 Arrogfm'ys Patented Oct. 5, 1954 FASTENING FOR RAHLWAY RAILS `lacob Rush Snyder, Cleveland, @hic Application September 3, 1948, Serial No. 47,654

(Ci. 23S-349) 7 Claims.

This invention relates to fastenings for railway rails and, more particularly, to rail fastenings of the kind which includes a spike driven into a wood tie and a substantially rigid clamp which is subjected to spring pressure for yieldingly holding the rail against a tie plate.

An object of the present invention is to provide an improved rail fastening of this kind in which the spike has increased holding power in the tie by reason of the fact that the portion of the tie surrounding a preformed bore into which the spike is driven is chemically treated and hardcned and thereby rendered resistant to shearing, crushing, iraying or rotting and also by reason of the fact that the treating material i;

establishes an adhesive bond between the spike and wood tie.

Another object of this invention is to provide such an improved rail fastening which includes yieldahie holding means engaging a rail flange,

or a rail iange and a tie plate, and in which the spike of the fastening has the above-mentioned increased holding power in the treated spike hole of the tie.

Another object is to provide an improved rail fastening of the character mentioned in which the spike is a so-called out spike having a plain stem as distinguished from a screw spike having a threaded stem.

Still another object is to provide an improved rail fastening of the character referred to in which a coil spring surrounding the spike serves the dual purpose of applying a desired load to the rigid clamp and acting as a gauge or stop for limiting the extent to which the Spike is driven into the tie.

A further object of this invention is to provide an improved rail fastening of the character mentioned in which the treating chemical is pressurized into the wood during the driving of the spike and the rigid clamp has an inclined spring f seat thereon adapted to cooperate with the spring so as to enable the spring to act as a gauge for the spike without preventing a desired yielding and rocking of the clamp to permit a limited amount of movement of the rail relative to the tie plate.

Yet another object of the invention is to provide an improved rail fastening of the character mentioned above and in which the chemical material is a water-insolvent cold-setting glue, preferably a potentially thermo-setting resin material such as a synthetic resin of the aldehyde type or a mixture of an aldehyde resin and a vinyl resin and which resin material is rendered actually thermo-setting by the addition of a lil catalytic material or hardener thereto such as formaldehyde.

Other objects and advantages of the invention will be apparent in the drawing and in the following detailed description.

This application is related to copending applications Serial No. 29,132, filed May 25, 1948. and Serial No. 47,653, led September 3, 1948, in which metal-to-wood fastenings embodying a wocd-hardening glue are disclosed and claimed.

in the accompanying sheetsof drawings,

Fig. 1 is a partial plan view showing a rail fastening embodying the present invention;

Fig. 2 is a vertical transverse section taken through the rail and tie plate at a point adjacent the clamp, as indicated by section line 2-2 of Fig. l, and showing the clamp in side elevation;

Fig. 3 is a vertical section taken through the fastening in a direction transversely of the rail, as indicated by section line 3 3 of Fig. 1;

Fig. /i is a sectional plan view taken through the fastening substantially on the irregular section line fl-ii of Fig. 3;

Fig. 5 is a perspective view of the rigid clamp in detached relation;

Fig. 6 is a transverse sectional detail taken on line 6--6 of Fig. 3;

Fig. 7 is a partial plan view similar to Fig. 1 but showing a modified form of the improved rail fastening;

Fig. 8 is a partial vertical section taken through the modined fastening in a direction transversely of the rail, as indicated by section line 8-3 of ig. '7; and

Fig. 9 is a perspective view showing the rigid clamp of the modified fastening in detached relation.

In the form of the improved rail fastening illustrated in Figs. l to 5, inclusive, thedrawings show a wood tie i@ having a tie plate Il supported thereon. A conventional railway rail l2 has its base flange i3 resting on the tie plate. The improved fastening also includes a fastening member in the form of a spike ill driven into the tie and a substantially rigid clamp i5 against which a coil spring IEE is compressed and which clamp applies pressure to the tie plate i l and the rail flange I3.

vThe tie It is a wood member such as a conventional tie which has been sawed or otherwise prepared from oak, pine or other suitable kind of wood timber. The tie may have its cuter surface creosoted, as is conventional practice in present day railroad construction. The tie I@ is provided with a preformed bore I'i which extends thereinto for an appropriate distance in a direction transversely of the grain of the wood. For a reason to be further` explained hereinafter and as shown in Fig. 6, the diameter of the bore II is smaller than the minimum transverse dimension of the stem of the spike I4. For example, when the spike has a 5A; inch square stem the bore would be 1/2 inch or 5%[6 inch in diameter.

The tie plate II is a conventional metal tie plate having an opening I8 therein for the stern of the spike I4-andwhich plate is supported on the tie I with the opening in overlying relation to the preformed bore I'I. The tie plate II is provided with an upstanding shoulder I9 extending thereacross and adapted to1be engaged by an edge of the base ange I3 for gauging or positioning the rail. The opening I8 extends through the tie plate at a point adjacent the base flange I3 and, in this instance, extends through the rail-gauging shoulder I9. The tie plate II may also be provided with one or more other openings 20` which extend therethrough at a point spaced outwardly from the shoulder I9.

The clamp `I is a substantially rigid L-shaped one-piece metal member extending in arched relation over the rail-gauging shoulder I9 of the tie plate II. The clamp is disposed so that the stem of the L-shape forms an arm 2I which extends inwardly toward the rail I2 in overhanging relation to the base flange I3. The arm 2l is'provided `at its inner endwith an end bearing portion 22 Awhich engages `the top of the base ange I3. The base of the L`shapeis disposed in upright'relation and forms the outer end 23 of the clamp. The upright outer end 23 is provided at its lower edge with a transverse seat or shoulder 24 which rests on the tie plate at a point just outwardly of the'opening I8. At an intermediate point thereof the clamp I5 is provided with an opening 25 through which the spike I4 extends `and which overlies the vopening I8 of the tie'plate. The clamp is provided with a substantially flat top bearing surface 26 which surrounds the opening 25 and forms' a seat for the lower end 'of the spring I6.

The spike I4 is here shown as being a cut spike having a h'ead I4'a and a stem I4b which isdriven into the bore Il of the tie through the opening I8 of the tie plate and the opening 25 of the clamp. The .stem I4b' is va plain or unthreaded stem, as distinguished from the threaded stem of a screw spike, and is preferably of a substantially square cross-sectional shape. As is common in railway spikes of this character, the inner end of the stem is provided with a substantially chisel-shaped'point I4c. The head I4a has a flat surface on the underside thereof forming a seat 21 for the upper end of the spring IB. At the junction of 'the head I4a with the square stem I4b the spike vis preferably provided with an enlargement or shoulder 28 of a substantially circular cross-section which telescopes into the upper end of the spring I6.

The spring I6 is a coil spring of suitable characteristics which is disposed around the stem of the spike I4 and is compressed against the bearing surface 2B of the clamp I5 by the head of the spike. The springapplies pressure to .the clamp which, in turn, transmits the pressure to the tie plate II and the flange I3 of the rail I2. The pressure applied to the tie plate by the outer end bearing portion 24 of the clamp holds the tie plate firmly against the tie I0. The pressure applied to the rail fiange I3 by the inner end bearing portion'22 of theclamp yieldinglyholds the rail against the tie plate. Duringthe passage of trains over the track the rail I2 is subject to some lifting or springing away from the tie plate II which is permitted by a rocking of the clamp on its outer end bearing portion 24 as a fulcrum. During this rocking of the clamp the arm portion 2| rises and falls relative to the tie plate as permitted by the flexing of the spring I6.

Reverting to the top bearing surface 26 of the clamp I5, it is pointed out that this surface is inclined relative to the axis of the spike I4 and slopes downwardly and inwardly toward the rail flange I3. As shown in the drawings, the upright outer end portion 2 3 of the clamp forms the high side of the inclined bearing surface and the arm portion 2i of the clamp forms the low side of the inclined bearing surface. In addition to the function of applying pressure to the clamp I5, the spring I6 also serves as a gauge or stop for limiting the extent to which the spike I4 is driven into the tie I0 and the ability of the spring to dothis is made Apossible -by the inclination of the bearing surface 26 of the clamp.

In assembling the improved fastening the spike I4- is driven into the bore I'I of the tie I0 for a distance to cause the convolutions at the outer side of the spring I6, that is the side remote from the rail I2, to be compressed to a substantially'solid'condition. Because of the inclined relation ofthe bearing surface -26 the convolutions at the opposite or'the inner side of the spring will remain spaced apart, as shown in the drawings. When the convolutions at the outer side of the-spring ,have been thus compressed to a vsubstantially solid condition this portion of the spring will actas a stop for preventing the spike from being driven further into the tie and the extent to whichthe 'spring has been compressed orloaded will then be such as to apply the desired pressure lto the clamp I5. The compressionof the convolutions to a substantially solid statev at the outer-side lof the spring during the installation of the fastening is usually only a temporary condition because as soon as `a few trains have-'passedover the track the tie plate will settle somewhat into the tie and the looseness thus produced will `betaken up by the spring and will result in av desired slight separation between the convolutions at the outer side of the spring;

In the improved fastening as above described, theenlargement or vshoulder 28 of the spike I4 extends into .the upper 'end yof the spring I6 and servesas al holding and positioning means which tends to maintainthe spring with its convolutions in vertical alignment and also acts through the spring in maintaining the clamp I5 in proper position. Theinner end of the clamp I5 is preferably provided With an upstanding transverse flange orshoulder 30 which is engaged by the outside of the lower lend of the spring I6 so that shifting of the clamp inadirection away from the rail will -be resisted by the spring. The opening25'of clamp I5 is preferably rectangular so as to cooperate with the square stem of the spike in preventing rotation of the clamp about the spike and the opening is of such size that its sides will engage vthe spike Yand limit the lateral shifting-of the clamp'in a'direction longitudinally of the rail. The'engagement ofthe spring with the shoulder 30"'enables lthe spring to hold the clamp in such positionthat the inner end of the clamp opening 25will notlscrapeH against the spike during .the above-'explained rocking of the clamp on the endportion124. In the arrangement just described the rectangular opening of the clamp and the square opening I8 of the tie plate enable the square stem Mb of the spike i4 to hold the clamp in proper position and prevent turning thereof.

The head Mia of the spike Hl is preferably of a size such that the underside 21 thereof will project laterally beyond the spring I6 and will present a fiat surface or shoulder adapted to be engaged by a spike pulling machine when it is desirable to use a power device of this kind for pulling the spike out of the tie. To permit the use of a hand operated spike pulling tool of the claw type, the outer end bearing portion 24 of the clamp I5 is provided with notches or recesses 3l at opposite sides thereof which permit the claws of the tool to engage under the outer end of the clamp.

In the form of the invention illustrated in Figs. 7 to 9, inclusive, a rail fastening is shown which is similar to the fastening illustrated in Figs. l to 5, inclusive, but in which the tie plate il is provided with an opening 32 having an extension recess or keyway 33 formed in the side thereof remote from the rail I2 and the clamp lili is provided with a depending lug or key 35 as an integral extension of the outer end bearing portion 2d and which lug engages in such extension recess or keyway. Since the depending lug 35, when engaged in the recess 33, will effectively prevent outward shifting of the clamp 3e, the upstanding transverse flange 30 has been omitted. In other respects the fastening of Figs. '7 to 9, inclusive is the same as the fastening illustrated in Figs. 1 to 5, inclusive, and described above and the same reference characters have been applied to corresponding parts.

In accordance with an important feature of the present invention, the spike I4 has increased holding power in the wood tie l0 and as the result of which a rail fastening of the type embodying a substantially rigid clamp and a coil spring for applying pressure thereto becomes much more practical and satisfactory for use on railway track. This increased yholding power also makes possible the above described use of socalled cut spikes having a plain or unthreaded stem in place of the more expensive screw spikes or hook bolts which have been required heretofore. In obtaining this increased holding power for the spike the portion of the Wood tie i0 immediately surrounding the bore I6 is treated with a chemical material indicated at 36 in the drawings and is thereby hardened and reinforced and rendered resistant to crushing, fraying, shearing and rotting. The material 36 also establishes an adhesive bond between the stem of the metal spike it and the wood of the tie.

The chemical material used in treating the portion of the tie surrounding the bore i6 can be any material suitable for this purpose which will produce the results explained above. This chemical material is preferably a cold-setting water-insoluble glue which is initially plastic or fiuid in character and can be readily introduced into the bore i6 and trapped therein for pressurization into the Wood during the driving of the spike lll. As this treating material any one of various synthetic resins can be used, for example a resin of the aldehyde or phenol aldehyde class such as phenol formaldehyde, urea formaldehyde, melamine formaldehyde or resorcinol formaldehyde.

The treating materials just mentioned are potentially thermo-setting in character and are rendered actually thermo-setting by the mixing of a hardener or so-called catalyst therewith, such as formaldehyde, andf the mixture formed by the resin and the hardener constitutes the treating material which is indicated at 36 in the above described rail fastenings. The hardener can be in either a powdered or liquid 'form and is added to the resin in suitable amounts, such as 5 per cent to 50 per cent by weight of the hardener to per cent to 50 per cent by weight of the resin, but the amount of the hardener to be used can be varied and will depend upon various factors including the specific resin employed and the setting characteristics desired for the treating material. Ordinarily, an amount of the hardener is employed which will produce setting of the resin in a period of from one to four hours at a normal temperature, that is to sai, a temperature ranging from 65 degrees to Si) degrees Fahrenheit.

It is important that the treating material 36 establish an adhesive bond between the wood tie and the spike as mentioned above. It is also important to prevent the treating material 35 from assuming a brittle state in which cracking or Grazing might occur in such material when it has become set. Both of these characteristics are obtained for the treating material 36 by incorporating a plasticizing agent, such as a suitable thermo-plastic material, in the aldeliyde resin prior to the mixing of the catalyst or hardener therewith. As this plasticizing agent a vinyl resin can be used such as vinyl acetate or vinyl butyral. The preferred plasticizing agent can be designated as a partially hydrolized polyvinyl acetate. The amount of the plasticizer to be used can be varied depending upon the particular aldehyde resin employed and the setting characteristics desired for the material. When the above mentioned polyvinyl acetate is used as the plasticizer 2' per cent to 20 per cent by weight is added to the resin. The treating material or glue 35 then comprises by weight approximately 93 per cent to 30 per cent of the aldehyde resin. Approximately 2 per cent to 20 per cent of the vinyl resin and approximately 5 per cent to 50 per cent of formaldehyde as a hardener.

It has been established by tests that when conventional cut spikes of the type commonly used in railroad track construction, such as a cut spike having a 5/8 inch square by 51/2 inch long stem, are driven into creosoted new woo-:l ties, such as red oak ties having preformed ,-95 inch diameter by 6 inch long bores therein for the spikes, an average force of approximately 3,0139 pounds will be required to pull the individual spikes out of the ties. As illustrative of the increased holding power of the spike itl in the tie it by reason of the use of the treating material 36 with which the portion of the tie surrounding the bore it is impregnated, it is explained that when Such a treating material was used in actual tests and consisted of approximately 95 per cent to 50 per cent by Weight of resorcinol formaldehyde resin and approximately 5 per cent to 50 per cent by weight of formaldehyde as a catalyst or hardener and was pressurized into the wood during the driving of the spikes and had become set, an average force of 5,000 pounds was required to pull the spikes out of the ties. When the treating material comprised approximately 84 per cent by weight of resorcinol formaldehyde resin, approximately 4 per cent by weight of vinyl resin and approximately 12 per cent by weight of formaldehyde as acatalystor hardener, an average :force o f 5,000 pounds to 6,000 pounds was needed to .pull the spikes out of theV ties. When theltreating ma,- terial comprised approximately `75 per cent by weight of resorcinol formaldehyde resin, approximately 14 per cent by weight of vinyl resin and approximately 11 per cent by weight of formaldehyde as a catalyst or hardener, an average force of from 7,500 pounds to 9,000 pounds was needed to p ull the spikes out of the ties.

It should be explained further that when the portion of the tie surrounding the bore has been reinforced byA chemical treatment, as explained above, and the treating material has become set the wood will be materially` hardened and greatly strengthened and will also be rendered substantially non-,absorbent and highly resistant to rotting.

The increased hardness of the portion of the tie surrounding the spike I4 will cause the spike to be firmly held `against lateral shifting during a prolonged period of service and loosening of the spike in the tie will thus be effectively prevented. In addition to this ability of the reinforced tie portion tormly hold the spike against lateral shifting and to resist crushing, shearing and rotting of the Wood fibers, the adhesive bond established by the treating material between the spike and the wood particularly when the vinyl resin is incorporated in the material results in.

the spike being also strongly held against axial movement out of the tie. It should also be explained that in forming this improved rail fastening the treating material or glue is preferably placed in thevbore I 6 in a bulk state although it can, if desired, be contained in a frangible capsule, and is forced into the surrounding portion of the wood tie during the driving of the spike. When the spike is initially started into the bore It some of the treating material 35 will flow upwardly around the spike, as indicated at 3l, and will form a protective coating and seal at this point which will prevent brine, or the like, dripping from railway cars from corroding the spike at this point.

From the foregoing description and the accompanying drawings it will now be readily understood that this invention provides an improved rail fastening, of the 4type embodying a substantially rigid clamp subjected to spring pressure, and which is simple in construction and very durable and reliable in service and requires the use of only relatively few parts adapted to be economically manufactured and installed. It will now also be understood that the increased holding power and durability, derived from the use of the chemical material with which thetie portion surrounding the bore is impregnated, permits the use of a cut spike having a plain or unthreaded stem in place of the more expensive screw spike or hook bolt which has heretofore been required in rail fastenings of this type. Additionally, it will be seen that the improved fastening provided by this invention will contribute greatly to thev longer life of the -wood tie beca-use the tie plate will always be firmly held against the tie andvpounding of the tie plate which has heretofore resulted in cuttingv and fraying of the tie will be substantially prevented.

Although the improved rail fastening provided by this invention has been illustrated and described herein to a detailed extent it will be understood, of course,v that the invention-is vnot to b'e regarded as beinglirnitepd.correspondingly in scope but includes. all changes and modifications coming within the terms of the claims hereof.

Having thus describedmy invention, I claim: l. In a rail fastening, a wood tie having a preformed bore therein, a tie plate on said tie and having an opening therein overlying said bore, a rail` having a base ange resting on said tie plate, a clamp comprising a substantially rigid one-piece metal body having one portion bearing onk said tie plate and another portion engaging the top of said base flange, said clamp also having an opening therein between said portions and a spring seat Vsurrounding said opening, a spike having a plain stem driven` into said bore through the openings of said tie plate and clamp and a head spaced above said spring seat, said stem having a tight-tting engagement in said bore such that portions of said stem are in direct contact with the portion of said tie immediately surrounding said bore, acoil spring disposed around said stem and compressed against said seat by said head, and a quantity of initially fluid but settable synthetic resin glue in saidy bore and distributed through the wood of ysuch surrounding portion of said tie and which inits set condition hardens the wood of said surrounding portion for increased holding engagement of said stem therewith and also forms an, adhesive bond directly between said stem and tie internally of the latter.

2. In a rail fastening of the character described, a wood tie having a preformed bore therein, a tie plate on said tie and having an opening overlying said bore, a rail having a base flange resting on said tie plate, a substantially rigid `clamp having one portion bearing on said tie plate and another portion engaging the top of said base. flange, said clamp also having an opening therein between said portions and a spring seat surrounding said opening, a spike having a stem driven into said bore through the openings of said clamp and tie plate and also having a head spaced above said spring seat, said stem having a tight-tting engagement in said bore such that portions of said stem are in direct contact with the wood of the side wall of said bore, and a coil spring surrounding said stern and `compressed against said spring seat by said-head, the portion of said tie immediately surrounding said bore being impregnated with an initially uid water-insoluble cold-setting synthetic resin glue which in its set condition imparts increased hardness and durability to such tie. portion and said stem having increased hold-ing power in said impregnated tie portion by reason of said increased hardness of said tie portion.

3. Ina rail fastening of the character described, a wood tie having a preformed bore therein, a tie plate on said tie and having an opening overlying said bore, a rail having a base flange resting on said tie plate, a substantially rigid clamp having one portion bearing on said tieplate and another portion engaging the top of said base flange, said clamp also having an opening therein between said portions and a spring-seat surrounding said opening, a spike having a stern ldriven into said bore through the openings of said clamp and tie plate and also Yhaving ahead spaced above said spring seat,

saidstem having a tight-fitting engagement in said bore such that portions of said stem are in direct contact with the wood of the side wall of said bore, and a coil ,spring surrounding said stem and-compressed against said spring seat by said head, the portion of said tie immediately surrounding said bore being impregnated with an initially fluid thermo-setting resin which in its set condition imparts increased hardness and durability to such tie portion and said stem having increased holding power in said tie by reason of the increased hardness of said tie portion, said thermo-setting resin also forming an adhesive bond directly between said stem and said tie internally of the latter.

4. In a rail fastening of the character described, a wood tie having a preformed bore therein, a tie plate on said tie and having an opening overlying said bore, a rail having a base nange resting on said tie plate, a substantially rigid clamp having one portion bearing on said tie plate and another portion engaging the top of said base iiange, said clamp also having an opening therein between said portions and a spring seat surrounding said opening, a spike having a stem driven into said bore through the openings of said clamp and tie plate and also having a head spaced above said spring seat, said stem having a tight-fitting engagement in said bore such that portions of said stem are in direct contact with the wood of the side wall of said bore, and a coil spring surrounding said stern and compressed against said spring seat by said head, the portion of said tie surrounding said bore being impregnated with a thermosetting resin which in its set condition imparts increased hardness and durability to such tie portion and said plain stem having increased holding power in said tie by reason of the increased hardness of said tie portion, said resin being initially contained in said bore in a iiuid condition and the bore being of a smaller diameter than the minimum transverse dimension of said stern such that during the driving of said spike said resin will be trapped and pressurized thereby in said bore and forced into said surrounding tie portion, said resin in its set condition also forming an adhesive bond directly between said stem and said tie internally of the latter.

5. In a rail fastening of the character described, a wood tie having a preformed bore therein, a tie plate on said tie and having an opening overlying said bore, a rail having a base ange resting on said tie plate, a substantially rigid clamp having one portion bearing on said tie plate and another portion engaging the top of said base flange, said clamp also having an opening therein between said portions and a spring seat surrounding said opening, a spike having a stem driven into said bore through the openings of said clamp and tie plate and also having a head spaced above said spring seat, said stem having a tight-iitting engagement in said bore such that portions of said stern are in direct contact with the wood of the side wall of said bore, and a coil spring surrounding said stem and compressed against said spring seat by said head, the portion of said tie surrounding said bore being impregnated with an initially fluid but settable thermo-setting resin which in its set condition imparts increased hardness and durability to such tie portion and said stem having increased holding power in said impregnated tie portion, said thermo-setting resin comprising a mixture of synthetic resin of the aldehyde class and a vinyl resin and said mixture being rendered thermo-setting by the addition of formaldehyde thereto as a hardener.

6. In a rail fastening, a wood tie having a preformed bore therein, a rail supported by said tie and having a base iiange, holding means of the yieldable type engaging said base ange for yieldably holding said rail relative to said tie including a fastener having a stem driven into said bore, said stem having a tight-fitting engagement in said bore such that portions of said stem are in direct contact with the wood of the side wall of said bore, the portion of said tie surrounding said bore being impregnated with an initially iiuid but settable wood-hardening and preservative material which in its set condition hardens the impregnated portion of said tie and forms an adhesive bond between said stem and tie such that said fastener has increased holding power in said impregnated tie portion.

7. In a rail fastening, a wood tie having a preformed bore therein, a tie plate on said tie and having an opening overlying said bore, a rail having a base flange resting on said tie plate, holding means of the yieldable type having one portion engaging said base flange for yieldably holding said rail relative to said tie plate and another portion engaging said tie plate for yieldably holding said tie plate relative to said tie and said holding means including a spike having a plain stem driven into said bore through said opening of the tie plate, said stem having a tight-fitting engagement in said bore such that portions of said stem are in direct,

contact with the portion of said tie immediately surrounding said bore, such surrounding portion of the tie being impregnated with an initially fluid but settable water-insoluble cold-setting synthetic resin glue which in its set condition hardens the wood of said surrounding portion and also forms an adhesive bond between said stem and wood tie.

References Cited in the i'ile of this patent UNITED STATES PATENTS Number Name Date 406,566 Dudley July 9, 1889 1,839,725 Armstrong Jan. 5, 1932 1,886,265 Andreianov Nov. 1, 1932 2,054,352 Willard Sept. 15, 1936 2,114,784 Maisch Apr. 19, 1938 2,132,572 Maney Oct. 11, 1938 2,161,259 Lindsay June 6, 1939 2,162,604 Clow June 13, 1939 2,175,453 Barcy Oct. 10, 1939 2,355,986 MacLean, Jr. et al. Aug. 15, 1944 2,357,498 Boyce et al. Sept. 5, 1944 2,376,200 Smidth May 15, 1945 2,387,009 Clarkson Oct. 16, 1945 2,389,464 Snyder Nov. 20, 1945 2,394,373 Gibbs Feb. 5, 1946 2,439,220 Rothfuchs Apr. 6, 1948 2,451,414 Snyder Oct. 12, 1948 FOREIGN PATENTS Number Country Date 500,109 Great Britain Jan. 30, 1939

Images