US2546487A - Draft rigging - Google Patents

Description

March 27, 1951 D. wlLLlsoN ET AL DRAFT RIGGING 3 Sheets-Shree?l l Filed Dec. 6, 1947 March 27, 1951 D. wlLLlsoN ET A1.

DRAFT RIGGING Patented Mar. 27, 1951 DRAFT RIGGING Donald Willison, Shaker Heights, and Hubert L.

Spence, East Cleveland, Ohio, assignors to National Malleable and Steel Castings Company, Cleveland, Ohio, a corporation of Ohio Applieetien December e, 1947, serie1N0.790,212

17 Claims. l

This invention relates to draft rigging for railway cars and more particularly to a combination yoke and shock absorbing mechanism.

Our invention provides various improvements over the inventions disclosed in the copending applications of Donald Willison, Serial No. '705,- 556, led October 25, 1946, and Serial No. 712,749, filed November 29, 1946.

An object of our invention is to provide a simple, efficient and lightweight combination yoke and cushioning mechanism.

Another object of our invention is to provide a combination yoke and friction shock obsorbing mechanism with provision for adjustment of the initial compression of the springs of the mechanism.

Another object is to provide a separable yoke member which is readily assembled or disassembled from its associated friction mechanism.

A further object is to provide a novel combination yoke and shock absorbing mechanism in which soft initial action occurs in both buff and draft.

Other objects and advantages of our invention will appear from the following description ofthe invention taken in conjunction with the drawings in which:

Fig. 1 is an elevational View partly in longitudinal vertical section of anl embodiment of the invention.

Fig. 2 is a transverse vertical sectional view taken along line 2-2 of Fig. 1.

Fig, 3 is a plan View partly in longitudinal horizontal section of the mechanism shown in Fig. 1.

Fig. 4 is a plan View partly in longitudinal horizontal section of a modification of the invention.

Fig. 5 is an elevational view partly in longitudinal vertical section of the mechanism shown in Fig. 4.

Fig. 6 is a plan view partly in longitudinal horizontal section of another modification of the invention.

Referring to the embodiment shown in Figs. 1 to 3 the yoke I0 of the mechanism comprises a forward or main member II. Member II Ycomprises a housing portion I2 which has a pair of spaced arms I3 and I 4 extending forwardly therefrom and adapted for operative connection to a car coupler. Arms I3 and I l are provided with aligned longitudinal openings I5 for receiving a vertical pin or key I6 which connects the yoke with the coupler shank I 8. The forward portions of openings I5 are flared rearwardly to permit key I6 to pivot about the forward end surfaces 20 thereof and thus allow horizontal angling of the coupler.

Slot 22 in coupler shank I8 is of such size as to receive key I6 with only a slight clearance therebetween so that the key moves with the shank in both draft and buff. In draft the coupler pulling force is transmitted to the yoke by the engagement of key I6 with surfaces of openings I5 in the yoke arms. In buff the yoke is stationary, and as the coupler moves rear-v wardly, key I 6 is carried rearwardly therewith in openings I5 which are of suiiicient length that, after the mechanism has traveled itsl full extent in buff, the key will not engage the rearward ends 2| of the openings. In this manner bufiing shocks on the key are avoided,

End surface 24 of the shank is curved and buiing surface 26 on front follower 28 is correspondingly curved to enable horizontal angling of the coupler in buil. Key I6 is held in place bya retainer 28 and bolt 30 which extends through lugs 32 on the underside of arm I4 of the yoke, A tie portion 33 extends across opening I5 on upper arm I3 and precludes key I6 from creeping or bouncing upwardly.

Within housing I2 are friction shoes 35 which slidably engage `the inner surface thereof. The inner surface of housing I2 comprises three pairs of angularly disposed plane surfaces 36 and each friction shoe 35 is provided with a pair of angularly disposed plane surfaces 31 for slidable engagement with one of the pairs of surfaces 36.

Shoes 35 are urged into engagement with the housing by means of wedge 38'which is interposed between the shoes and follower 28. Each shoe at its forward end is provided with a wedge face 40 which engages a complementary face 4I on wedge 38. The action of wedge Y38 in the operation of the mechanism is to urge the shoes out'- wardly with increasing force as relative lungi--4 tudinal movement occurs between shoes 35 vand housing. I2 against the. resistance of main springs d3 and 44. Surfaces 36 preferably taper inwardly in a rearward direction so as to vincrease the amount of friction vgenerated by the mechanism and to' effect quick release betweensurfaces 36 and 3l upon release of the draft or bufling force to permit the parts to return to normal position.

Each shoe has a rearwardly extending annular portion 46 the end of which engages a front spring seatmember 48. Member 48 comprises a forward circular portion 50 which engages an.-j nular portions 46 of the shoes, and a rearward circular portion 52 which engages spings t3y and 44. Portions 15I! and 52 are joined by tie members 54.v Forward portionv 56 has an opening 56 for receiving auxiliary spring 58 which extent'ls t 3 into member 48 and engages portion 52 thereof on the side opposite from springs 43 and 44. An annular flange 59 on portion 50 serves to maintain member 48 centered. The forward end of spring 58 engages a seat member 68 the cylindrical forward end 82 of which engages the front wall 64 of wedge 38. Wall 64 is recessed to receive end 62 of the seat and thus serves to maintain it in centered position. It will be observed th'at a substantial clearance exists between seat 80 andr shoes 35. Thus auxiliary spring 58 reacts between wedge 38 and seat member 48. The function of the auxiliary spring will be explained in a succeeding part of this description. Springs 43 and 44 are held in place by means of a pair of spaced spring tie bolts I secured to housing I2 and an adjustable rear spring seat I2 mounted on the bolts. The forward ends of bolts I0 are preferably provided with recesses 'I3 in heads I4 thereof for receiving a pair of spaced lugs I6 on the top and bottom of housing I2. It will be seen that lugs 'I6 not only secured the bolts against rearward movement relative to housing I2 but prevent axial rotation of the bolts. It will also be observed that suflicient clearance is provided rearwardly of heads 14, as at 18, to permit forward movement of bolts 'IIJ so as to withdraw lugs I6 from recesses I3 and thus permit removal of the bolts during disassembly of the mechanism.

Spring seat 12 which provides the rear abutment for springs 43 and 44 comprises a spring engaging portion 80 which has openings 8l for receiving bolts A'I0 and is reinforced by parallel ribs 82. bolts I8 by means of nuts 83 which are screwed onto the threaded ends 84 thereof. Thus the position of seat 12 relative to bolts 'i0 may be varied so as to obtain the desired amount of initial compression of main springs 43 and 44 and also to obtain the desired amount of relative compression between the main springs and the auxiliary spring 58. Nuts 83 normally are held against rotation by ribs 82. Seat 'I2 is provided with a boss 85 for positioning the rearward end of springs 43 and 44 while a similar boss 86 on front spring seat 52 positions the forward end of the springs.

Draft pocket 90 (shown in dot-dash) has front and rear stops 9I and 92 respectively. Follower 28 normally engages front stops 9| while lateral fianges 93 on housing I2 normally engage rear stops 92.

l In neutral position of the mechanism as shown in Figs. 1 and 3, follower 28 engages stops 95 on yoke II which are positioned so as to space the follower approximately the proper amount from flanges 93 to facilitate insertion of the mechanism into the draft pocket. Follower 28 also has a projection 96 extending into Yopening 91 in the forward end of wedge 38 to tie the two parts together.

The function of auxiliary spring 58, which reacts between wedge 38 and front spring seat member 48, is to decrease the friction developed between shoes 35 and housing I2 particularly during the initial movement of the car coupler in bul or in draft and thereby obtain softer cushioning action. To obtain substantially free spring jaction at the start of movement, spring 58 is preferably so constructed and arranged as to be placed under approximately the initial compression applied to springs 43 and 44. Thus if the initial compression of spring 58 is equal to the combined compression of springs 45 and 44, wedge Seat 'I2 is adjustable longitudinally of 4 38 will not urge shoes 35 into engagement with housing I2 while the mechanism is in neutral or inactive position. Therefore, whenevera force in buff or draft is applied to the mechanism by the coupler the initial movement thereof will be resisted substantially by springs 43 and 44 only. However, as the force applied to the unit increases, the compression of springs 43 and 44 increases while the compression of the auxiliary spring remains substantially the same, the increase in compression of springs 43 and 44 causing wedge 38 to urge shoes 35 into frictional contact with housing I2. Thus soft initial cushioning action is provided for light shocks while the combination of friction and the resistance of springs 43 and 44 is provided for cushioning intermediate and heavy shocks. The taper of surfaces 36 causes shoes 35 to move rearwardly relative to housing I2 a slightly greater amount than wedge 38 during actuation of the unit in buff or draft, thereby increasing the friction generated between the shoes and housing and also causing spring 58 to expand slightly from neutral position. The slight expansion of spring 58, while not appreciable, tends to increase the friction generated between the shoes and housing.

If desired, the initial compression applied to spring 58 may be greater than that of the main springs so that still softer initial cushioned action will result. However, in order to prevent any looseness of shoes 35 in housing I2, it is desirable that the initial compression of the main springs be adjusted so that it is slightly greater than that of the auxiliary spring.

The operation of the mechanism is as follows:

Assuming first that a force in buff is applied to the coupler, end surface 24 of coupler shank I8 engages bung surface 26 on front follower 28. The yoke remains stationary with anges 93 of housing I2 in engagement with rear stops 92 as the coupler urges follower 28 rearwardly toward front surface 98 of the housing. This movement is resisted initially substantially by springs 43 and 44 due to the action of spring 58 as previously described. However, as the effect of spring 58 is overcome by the increasing force applied by the coupler, wedge 38 urges shoes 35 against housing I2 as the parts move rearwardly. The friction generated between the shoes and housing increases rapidly upon further movement of the coupler rearwardly. Movement of the coupler is thus opposed by the friction generated and by the resistance of springs 43 and 44 until the end of travel of the mechanism when follower 28 engages front surface 98 of housing I2.

The parts of the mechanism are so arranged that with follower 28 in engagement with housing I2 a substantial amount of free travel of springs 43 and 44 remains.v Since these springs can never be compressed solid the maximum force applied to bolts 'IIJ willnever exceed the compression of the springs and therefore this portion of the mechanism including lugs 'I8 maybe of comparatively light construction.

When a draft or pulling force is applied to the coupler, yoke IIJ is pulled forwardly' by key I6 while follower 28 remains stationary in engagement with front stop lugs 9|. During this operation housing I2 moves forwardly relative to shoes 35 and wedge 38, otherwise the action of the mechanism is the same as when a force in bui is applied thereto. The initial movement is resisted substantially by the free spring action vof springs 43 and 44 while the succeeding moveand housing I2 and by springs 43 and 44. As in buff engagement occurs between follower 28 and surface 88 of the housing at the end of the travel in draft, and the springs are never compressed solid. @Throughout the operation of the mechanism in buff or draft springs 43 and 44 exert a rearward force on spring seat 'I2 so that bolts I0 are always under tension and lugs 'I6 remain interlocked with heads I4 of the bolts. Since springs 43 and 44 are placed under a predetermined amount of initial compression when the mechanism is assembled there never is any danger of the bolts ever becoming disconnected from housing I2.

To assemble the mechanism the yoke l0 is preferably placed in a vertical position with the for- Vward ends of yoke arms 3 and I4 resting on a work bench or other convenient support. Next VAfollower 28, wedge 38, shoes 35, seat 6.0, spring 58,

seat 48, and springs 43 and 44 are applied in the order named. Thenl bolts 'I0 are interlocked with lugs `|6 and a wedge 39 (shown in dot dash) is temporarily inserted between the end of the head of each bolt and the end of housing I2 tc maintain the bolts in this position. Seat 'I2 is next applied to the ends of the bolts and a force applied thereto by means of a press or similar device to "compress springs 43 and 44 an amount sufficient to permit nuts 83 to be screwed to the position which will give the desired initial compression of the main springs. Thereafter, the force exerted on seat 12 is released and with the seat in engagement with nuts 83, springs 43 and 44 will be yunder the desired initial compression in relation to auxiliary spring 58. As previously noted parallel flanges 82 on seat 'I2 preclude turning of nuts 83 after the mechanism is assembled. It will be noted that while no provision is made for varying the initial compression applied to spring 58, the adjustment of seat 12 longitudinally of 4vbolts 10 provides sufcient control of the compression applied to springs 43 and 44 so that any desired ratio of the precompression of the main springs to that of the auxiliary spring may be obtained. Thus seat 12 may be adjusted so that the compression of the main springs is greater' or vless than that of spring 58.

Disassembly of the mechanismfis accomplished by applying the preceding steps of assembly in reverse order.

In the modification shown in Figs. 4 and 5 the friction housing |02 is separable from the yoke main portion |04. This construction permits replacement of the friction housing in the event of wear without discarding the yoke main .portion |04; In other respects the friction generating 'portion of the mechanism is similar to that of the previous embodiment.

Yoke portion |04 comprises horizontal top and Abottom arms |06 and |08, respectively, which are adapted for operative connection to a car coupler lin a manner similar to arms I3 and I4 of the pre- -vious embodiment. The yoke arms are formed with transversely extending recesses ||0 for receiving housing |02 and anchoring it thereto.

Extending rearwardly from the end of the hous- "ing portion |I8 across the ends thereof. A' pair '0f spaced lugs 6 formed on the upper and lower arms of the yoke are interlocked with spring retaining bolts 'I0' in the same manner as in the previous embodiment. Rear spring seat 'I2' is adjustable by means of nuts 83. Associated with the yoke and housing are follower 28', Wedge 38', friction shoes 35', front spring 'seat member 48', and springs 43 and 44', all of these parts'being similar to the corresponding parts of the previous embodiment. Guide lugs |20 extending into openings I I6 are provided on follower 28' to prevent lateral displacement of the yoke in service. The auxiliary spring 58 has not been applied'to the present embodiment but may be added, if desired, to provide softer initial cushioning action.

' Assembly of the mechanism is the same as for `the previous embodiment with the exception that after follower 28 has been applied housing |02 is applied by sliding it in a transverse direction between arms I06 and |08 with flanges I|2 interlocking with lugs II4. Thereafter wedge 38', shoes 35', seat member 48 and springs 43 and y44' are applied. Final assembly is completed as before by applying the desired amount of compression to springs 43 and 44', and adjusting nuts 83 to the proper position.

In the modification shown in Fig. 6 the friction housing |30 is integral with the yoke similar to housing I2 of the embodiment illustrated in Figs. l t0 3. Also friction shoes |32 and wedge |34 are similar to the corresponding parts of the first embodiment. Lugs or straps |36, t0 which retaining bolts |38 are attached, are U -shaped and extend rearwardly from the top and bottom of housing |30. Transverse portion |40 of each strap has an opening |42 for receiving one of the retaining bolts |38. It will be observed that bolts |38 are reversed from the position of the bolts shown in the preceding embodiments, in that the threaded ends of the bolts are adjacent the friction housing. In this manner the bolts are merely inserted through openings |42 and nuts |44 screwed thereon by turning the bolts. A feature Vof this construction is that a standard bolt and nut may be used to adjustably connect rear spring seat |46 to the friction housing. As in the previous embodiments seat |46 is provided with spaced parallel anges |48 which prevent rotation of the bolts relative to the seat. Strap |30 is so formed that portion |40 is spaced rearwardly of the end of housing |33 to allow for suflicient adjustability of the bolts in a longitudinal direction, thereby providing means for varying the initial compression applied to spring means |50 (shown in dot-dash). Also the longitudinal portions |52 of the straps are so spaced as to limit the rotation of nuts |44 relative thereto.

It will be noted that front spring seat member |54 is located within housing |30 and comprises a flat plate portion which is interposed between shoes |32 and spring means |50. Also, shoes |32 are shorter than those of the previous embodiments so that the spring means extends'into the friction housing and thereby permits a substantial reduction in the rearward extent of the mechanism, making this construction particularly suited for application to existing cars in which a limited amount of space is available for the mechanism. The inner surface of housing |30 is preferably flared at its rearward end as at |56 so that during return of the mechanism following a force in buff, front spring seat 54 will be guided back into the housing in the event it is displaced laterally from its central position. :v c

" Assembly of the mechanism is similar to that of the first embodiment. After front follower |58, wedge |34, shoes |32, spring seat |54, spring means |56 and seat |46 are applied in the order named, a compressive force is applied to seat |46 in any suitable manner. Bolts |38 are then applied and adjusted to the position which will give-.the desired amount of initial compression to the spring means after the release of the compressive force.

The terms and expressions which we have employed are used as terms of description and not of limitation, and we have no intention, in the use of such terms and expression, of excluding any equivalents of the features shown and described orV portions thereof, but recognize that various modications are possible within the scope of the invention claimed.

What we claim is:

1. A combination yoke and friction shock absorbing mechanism comprising a housing member having forwardly extending arms adapted for operative connection to a car coupler, friction shoes within said housing adapted for longitudinal slidable engagement with the inner surface thereof, a wedge member for actuating said shoes, spring' means for opposing movement of said shoes relative to said housing member, a rear spring seat for said spring means, and tie members for securing said seat to said housing, said ltie members being adjustable to kdraw said seat forwardly during assembly of said mechanism to place said spring means under predetermined initial compression.

2. In a draft rigging for railway cars a yoke member having a friction housing, said housing including an inner friction surface and having lateral extensions for engagement with buing means on the car, a follower member within said yoke for engagement with pulling means on the car, friction shoes engaging said inner surface of said housing and being slidable relative thereto in a longitudinal direction, a wedge member interposed between said shoes and said follower and being adapted to urge said shoes against said surface of said housing, spring means for opposing relative longitudinal movement between 4said shoes and housing, a spring seat for the rear end of said spring means, and tie members for securing said seat to said yoke member, said tie members being adjustable to draw said seat forwardly toward said housing during assembly of the mechanism to place said spring means under predetermined initial compression.

3. In a draft rigging for railway cars, a yoke member adapted for operative connection to a car coupler, said yoke having a friction housing, said housing having lateral extensions adapted for engagement with buiiing stops on the car, a follower member within said yoke adapted to engage p-ulling stops on the oar, friction shoes adapted for longitudinal slidable engagement with the inner surface of said housing, a wedge member interposed between said shoes and said follower for wedging said shoes against said surface, spring means for opposing relative longitudinal movement between said shoes and housing, stop lugs extending rearwardly from the end of said yoke, bolt members extending rearwardly from said yoke, the forward ends of said bolt members engaging said lugs to prevent rearward movement thereof relative to said yoke, and a spring seat member mounted on said bolt members, said member forwardly toward sadyoke during asanism a yoke member comprising a forward portion having a housing for carrying part of said mechanism and a rearwardly extending spring carrying portion, said rearward portion comprising spaced bolts and a longitudinally adjustable spring seat member at the rearward ends of said bolts, and lugs extending rearwardly from said housing, the forward ends of said bolts being enlarged and having recesses therein for receiving said lugs to interlock said forward and rearward yoke portions.

5. In a combination yoke and cushioning mechanism, a yoke member having a friction housing, friction shoes slidably engaging said housing in a direction lengthwise thereof, wedge means for urging said shoes into engagement with said housing, spring means for opposing relative longitudinal movement between said shoes and `housing, and means for carrying said spring means comprising a pair of spaced retaining bolts and a spring seat member at the rearward ends of said bolts adjustable relative thereto in a lengthwise direction, and lugs extending rearwardly from Vsaid housing, the forward ends of said bolts containing recesses for receiving said lugs to interlock said bolts and housing. K

6. A yoke for an associated friction mechanism comprising a friction housing, a pair of arms extending forwardly from said housing and adapted for connection to a car coupler, spaced bolts extending rearwardly from said housing, a spring seat member mounted on said bolts and being adjustable longitudinally thereof, nut means on said bolts for securing said member thereon, and lugs extending rearwardly from said housing and interlocking with said boltsto secure the latter to said housing. n

7. A yoke for an associated friction mechanism, said yoke comprising a friction housing, said housing having attachment lugs extending rearwardly therefrom, said lugs having lateral .extensions spaced rearwardly of said housing, bolt members secured to said lugs and extending rearwardly, said bolt members having portions received between said lateral extensions and the end of said housing, and a spring seat member longitudinally adjustably mounted on said bolt members.

8. In a combination yoke and shock absorbing mechanism, a yoke member having a friction housing, shoes slidably engaging the inner surface of said housing in a direction lengthwise thereof, wedge means for wedging said shoes against said surface of said housing, spring means carried by said yoke for opposing sliding move- 'ment of said shoes relative to said housing,said spring means being under predetermined initial compression, a spring seat member interposed between said spring-means and said shoes, and

-other spring means reacting between said seat member and said wedge means, said last named spring means being under predetermined initial compression for opposing the expansive force of said first named spring means.

9. In combination with a yoke having a friction housingand a spring carrying portion detachably secured to said housing, friction shoes within said housing and in longitudinal slidable engagement with the inner surface thereof, spring means in said yoke spring carrying portionfor opposing relative sliding movement betweensaid shoes and housing, a spring seat member interposed between said shoes and said spring means, said springV means being under predetermined initial compression, a wedge member for urging said shoes rearwardly against the resistance of said spring means, and other spring means within said housing and reacting between said spring seat member and said wedge member, said last named spring means being under predetermined initial compression for opposing the expansive force of said rst named spring means.

10. In combination with a yoke having a friction housing and a rearwardly extending spring carrying portion, spring means in said spring carrying portion, a spring seat memberengaging the forward end of said spring means, said spring seat having an apertured forwardly extending portion, friction shoes in longitudinal slidable engagement with said housing and engaging said forwardly extending portion of said seat member, a Wedge member for urging said shoes into engagement with said housing against the resistance of said spring means, another spring seat within said housing and engaging said wedge member, and other spring means extending into said apertured portion of said rst named spring seat and reacting between said first named seat and said last named seat, said last named spring means being under predetermined initial compression.

11. In a combination yoke and shock absorbing mechanism, a yoke having a friction housing, friction shoes in longitudinal slidable engagement with said housing, a wedge member for actuating said shoes, spring means for opposing movement of said shoes relative to said housing, a rear spring seat for said spring means, a front spring seat for said spring means, adjustable tie members for carrying said rear spring seat, said tie members being adapted to draw said seat forwardly during assembly of said mechanism to place said spring means under predetermined initial compression, and other spring means reacting between said wedge member and said front spring seat, said last named spring means being under predetermined initial compression.

12. In a combination yoke and shock absorbing mechanism a yoke having a friction housing, abutment means in the forward end of said yoke, a follower member engaging said abutment means, friction shoes Within said housing and being slidable relative thereto in a longitudinal direction, a. wedge member for actuating said shoes interposed between said shoes and said follower member, a front spring seat member engaging the rear end of said shoes, spring means engaging said front spring seat member and opposing relative movement between said shoes and housing, a rear spring seat member, adjustable tie members connecting said rear spring seat vmember to said housing, said tie members being shoes in longitudinal slidable engagement with said housing member, spring means for opposing movement of said shoes relative to said housing member, adjustable spring carrying means connected to said arms, said means comprising tie members connected to and extending rearwardly from said arms, a spring seat member mounted on said tie members, and threaded members on said tie members for drawing said seat member toward the end of said arms.

14. In a combination yoke and friction shock absorbing mechanism a yoke having a pair of spaced arms adapted for operative connection to a car coupler, a housing member connected to said arms and being separable therefrom, friction shoes in longitudinal slidable engagement with said housing member, spring means for opposing relative movement between said shoes and hous- 'ing member, said yoke having an adjustable spring carrying portion comprising a pair of spaced bolt and nut members, and a spring seat member mounted on said bolt members.

15. In a combination yoke and cushioning mechanism, a yoke member, a housing member carried by said yoke member, said housing member being interlocked with said yoke member for movement therewith in a longitudinal direction, said yoke member having rearwardly extending lugs, a spring seat member, and tie members longitudinally adjustably connecting said seat member to said yoke member, said tie members being connected to said lugs and extending rearwardly therefrom. f

16. In a combination yoke and cushioning mechanism, a yoke member comprising afriction housing and forwardly extending arms for operative connection to a car coupler, spring means carried by said yoke, said housing having rearwardly extending straps, each strap having a bolt receiving opening, a spring seat member for engaging the rear end of said spring means, bolts for connecting said seat member to said straps, said bolts extending through said openings, and nut means on said bolts adjacent said straps for longitudinally adjustably securing said bolts to said straps.

17. A yoke for an associated friction mechanism including spring means, said yoke comprising a friction housing, a pair of arms extending forwardly from said housing and adapted for connection to a car coupler, a pair of spaced bolts extending rearwardly from said housing for carrying said spring means, a spring seat member carried by said bolts and being positioned adjacent the head ends thereof, strap means extending rearwardly from the end of said housing, the threaded ends of said bolts being received by said strap means, and nut means on the threaded ends of said bolts for longitudinally adjustably securing said bolts to said strap means.

DONALD WILLISON. HUBERT L. SPENCE.

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

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