US3516207A

US3516207A - Belt grinding and polishing machine

Info

Publication number: US3516207A
Application number: US658277A
Authority: US
Inventors: Stephen Bader
Original assignee: BADER STEPHEN AND CO Inc
Current assignee: BADER STEPHEN AND CO Inc
Priority date: 1967-08-03
Filing date: 1967-08-03
Publication date: 1970-06-23
Anticipated expiration: 1987-06-23
Also published as: FR1577596A; DE1752906A1

Description

June 23, 1970 s. BADER 3,516,207

BELT GRINDING AND POLISHING MACHINE Filed Aug. 5, 1967 .4 Sheets-Sheet 1 IN VENTOR. 675 /45? 5,905

June 23, 1970 s. BA'DER 3,516,207

BELT GRINDING AND POLISHING MACHINE Filed Aug. 5, 1967 .4 Sheets-Sheet 2 IN VEN TOR. 67'EP/9E/V 8/9051? wwqz m w Filed Aug. 5, 1967 s. BADER 3,516,207

BELT GRINDING AND POLISHING MACHINE .4 Sheets-Sheet 3 "MT! I BY wwwm gw IIN\I/ENTOR.

June 23, 1970 SnBADER BELT GRINDING AND POLISHING MACHINE .4 SheetsSheet 4 Filed Aug. 5, 1967 INVENTOR. 675F195 5 905? BY 4.4 1; MW W flT/OP/VEXS United States Patent 3,516,207 BELT GRINDING AND POLISHING MACHINE Stephen Bader, Valley Falls, N.Y., assignor to Bader, Stephen & Co. Inc., Valley Falls, N.Y., a corporation of New York Continuation-impart of application Ser. No. 375,747, June 17, 1964. This application Aug. 3, 1967, Ser. No. 658,277

Int. Cl. 1324b 21/00 US. Cl. 51-135 17 Claims ABSTRACT OF THE DISCLOSURE A belt sander having an inner and an outer portion and a second mounting member pivotally connected to the inner portion, rollers mounted on each portion for carrying an endless belt; and a tracer wheel mounted on the outer portion for engaging the surface of a workpiece for adjusting and controlling the depth of grinding.

This application is a continuation-in-part application of my copending application Ser. No. 375,747, filed June 17, 1964, now Pat. No. 3,335,528.

The invention relates to grinding and polishing machines and more particularly to a machine of the type employing an endless belt.

Heretofore, difiiculties have been experienced in grinding weld seams and surfaces on the inside of large tanks or the outside of missiles due to uneven grinding or gouging. It is necessary that such surfaces not only be ground evenly but also the amount of surface material removed or the depth of grinding must be accurately maintained throughout a large surface area. Actually, if excess material is removed, in many instances the entire work-piece may be rendered unfit for use. Accordingly, it is an object of the present invention to overcome the difficulties encountered with the prior art.

My invention contemplates a construction wherein a belt sander of the foregoing class is provided with a mounting member having an inner portion and an outer portion. A second mounting member is pivotally connected to the inner portion. Rollers are mounted on each of the portions as well as the second mounting member, and an endless belt is supported against the outer surfaces of the rollers with means being provided for tensioning the belt. A tracer wheel is mounted adjacent the roller on the outer portion for engaging the surface of a workpiece and means are provided for adjusting this wheel in order to adjust the depth of grinding on the surface of the workpiece.

As a feature of my invention, I use a bifurcated hublike portion at the outer end of the outer portion of the mounting member for mounting the contact roller on the side thereof and for mounting the tracer support between the forks for vertical movement. I provide means for positioning the tracer wheel so that the depth of penetration of the contact wheel into the surface of the Work-piece can be readily adjusted, as desired. Such means include a set screw threadably mounted on the hub-like portion and penetrating therethrough to engage the top surface of the tracer support member.

As another feature of my invention, I provide supporting wheels mounted on an axle which, in turn, is mounted on the inner portion of the mounting member for trans- 3,516,207 Patented June 23, 1970 ICC verse movement with respect to the longitudinal axis of the belt sander. This allows the entire weight of the belt sander to be carried by the surface of the Work-piece and thereby reduces the physical effort required by the operator.

Another feature of this invention resides in the provision of a new and improved belt sander of the class described having a mounting member including an inner portion and an outer portion, and wherein said outer portion has a pair of prongs extending from the outer end and a contact roller mounted on and supported between the prongs. The diameter of the contact roller is substantially greater than the distance between the prongs. This serves to allow the belt sander to reach inside surfaces while rigidly supporting the contact wheel.

In another form of my invention I provide a belt sander having a contoured contact wheel for engaging the inside surface and other hard to reach surfaces of a work-piece.

As a further feature of the present invention, the belt sander is provided with a plate-like resilient shield member which may be fixedly connected to the inner portion by means of a first pin and a spaced second pin mounted on the inner portion of the mounting member. The shield member extends from the second member to the first pin, and substantially around same in a clamp-like manner, and then to the second pin. Still further, the shield member has a reduced cross-sectional area on the ends approaching the fixed connection for varying the resiliency depending upon the degree of rotational movement of the second member. The reduced cross-sectional portion may take the form of a tapered tongue or a bifurcated fork having a V-shaped gap therebetween. This serves to render the shield member more flexible and also to provide less tensioning of the belt when smaller belt Widths are employed. It also provides varying tensions for belts having different stretch characteristics.

The invention, according to another form thereof, resides in the provision of a belt sander having means for mounting it on the tool-post of a lathe. This adds versatility to the belt sander, thereby allowing the same machine to meet a number of different operational functions.

A further feature of the invention is the provision of a belt sander which is of simple and practical construction, which is relatively inexpensive to manufacture, and which is otherwise well suited for its intended purpose.

There has thus been outlined rather broadly the more important features of the invention in order that the detained description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated.

There are, of course, additional features of the invention that will be described hereinafter which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception on which this disclosure is based may readily be utilized as the basis for the designing of other structures for carrying out the several purposes of the invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope of the invention.

Several embodiments of the invention have been chosen for purposes of illustration and description and are shown in the accompanying drawings, forming a part of the specification, wherein:

FIG. 1 is a side elevation showing the belt grinding 3 and polishing machine constructed in accordance with the concepts of this invention;

FIG. 2 is an end elevation of the belt grinding and polishing machine of FIG. 1;

FIG. 3 is an enlarged fragmentary perspective view of the outer portion of the support member and including the contact wheel as well as the tracer wheel;

FIG. 4 is a plan view of the machine of FIG. 1;

FIG. 5 is an enlarged perspective view of the outer portion of the support member according to one form of the invention;

FIG. 6 is an enlarged perspective view of theouter portion of the support member according to another form of the invention;

FIG. 7 is an enlarged fragmentary view of a portion ofthe resilent plate-like shield member showing the end having a reduced cross-section area;

FIG. 8 is an enlarged fragmentary view similar to FIG. 7 but showing another form of my invention;

FIG. 9 is a perspective view of the belt sander of my invention mounted in combination with a lathe; and

FIG. 10 is another perspective View of the belt sander of FIG. 9.

In the embodiment of the invention illustrated in FIGS. 1-4, the belt sander includes a mounting member 10 having an outer portion 12 and an inner portion 14, the outer portion 12 being swivelly connected to and supported by the inner portion as by means of pivot pm 16. An adjusting screw 18, having a finger actuated rotating knob 20, engages the outer portion 12 as at 22 and threadedly engages the inner portion as at 24 for purposes of aligning the outer portion 12 with respect to the inner portion 14.

Still referring to FIGS. 1-4, the outer portion 12 has a hub-like portion 26 at the outer end thereof. A work engaging or contact roller 28 is rotatably mounted on a hub-like portion, as at 30. It will be appreciated that the outside surface of the contact roller 28 is adapted to support an endless abrasive belt 32 against the counterforce of an engaging workpiece.

As best seen in FIGS. 1-4, the inner portion 14 of the mounting member 10 is provided with extensible mounting members 34 and 36, member 34 being substantially a hollow square form as viewed in cross section and member 36 being of substantially the same configuration, but of smaller size to slidably engage the inside of member 34 in a telescopic manner. Member 34 is provided with an elongated slot 38 (FIG. 1) and an adjusting screw 40 serves to secure the members 34 and 36 in their selected relative positions.

A hand grip 42 is mounted on the inner portion 14 as at 44, FIGS. 1 and 4, for purposes of allowing the operator to readily grasp the machine during normal operation.

As best seen in FIGS. 2 and 4, the inner portion 14 is provided with an air motor 46 mounted on the side thereof, as at 48. The air motor 46 is provided with an air hose connection 50 of standard construction well-known in the trade. A drive shaft 52, FIG. 1, extends from an air motor 46 and a drive roller 54 is keyed thereto, as at 56. The endless belt 42 is supported and driven by the outside surface of the drive roller 54.

The inner portion 14 is further provided with an annular groove 58 (FIG. 4) which extends from a first location 60 (FIG. 1) to a second location 62 (FIG. 1) and is further disposed between the drive roller and the air motor. A second mounting member or mounting plate 64 is concentrically mounted on shaft 52 within the annular groove 58. The mounting plate 64 is provided with raised portions 66 and 68 (FIG. 1) which limit the amount of rotational travel of the mounting plate 64. Consequently, when the mounting plate is rotated in a counterclockwise direction, as viewed in FIG. 1, the raised portion 68 strikes the base of the annular groove 4 68 at location 68. When the mounting plate 64 is rotated in a clockwise direction, as viewed in FIG. 1, the raised portion 66 of the mounting plate 64 engages the base of the annular groove 58 at location 60, and thereby limits the amount of clockwise rotational travel of the mounting plate 64.

Still referring to FIG. 1, roller 70 is rotatably mounted on shaft 72 which is mounted on mounting plate 64, and the endless belt 32 is adapted to engage the outside surface thereof.

A pair of pins 74 and 76 (FIG. 1) are fixedly connected to the hand grip 42 of the inner portion 14, and a pin 78 is fixedly connected towards the outer portion of the mounting plate 64. A resilient safety guide member 80 is anchored at its inner end by being partially passed around pin 74 and frictionally engaging pin 76. The outer end of the guide member 80 is adapted to frictionally engage pin 78, as shown in FIG. 1. As seen in FIGS. 1 and 2, the resilient safety guide member 80 is disposed between the hand grip and the moving belt 32, and hence acts as an effective guard for protecting the operator. It is particularly noted that in the event that the belt '32 should break, the loose end portions thereof would not slap around and hit the operators hand while gripping the hand grip 42.

Further, it will be appreciated that the resilient safety guide 80 exerts a force against pin 78 tending to rotate the mounting plate 64 in a counterclockwise direction as viewed in FIG. 1, and thereby increases the linear distance between the roller 70 and the roller 28, and consequently increases the tension force on the belt 32,

proportionately. Further, in one form of my invention, as

best seen in FIG. 7, the shield member 80 has a reduced cross-sectional area 82 on the end adjacent ends 74 and 76 for varying the degree of resiliency depending upon the degree of rotational movement of the second member. In the form as shown in FIG. 7, the reduced crosssectional area 82 is in the shape of a tapered tongue, and in the form as shown in FIG. 8, the reduced cross-sectional area is in the shape of a bifurcated fork 84 having a V-shaped gap 86 therebetween.

In operation, a belt member 32 is loosely positioned about the

rollers

28, 54 and 70 and a rough adjustment of the linear distance between the rollers is obtained by adjusting the length of the mounting member 10 by means of the adjusting screw 40. Final tensioning of the belt 32 is achieved by means of the resilient safety guard 80 which, as pointed out hereinbefore, tends to rotate the mounting plate 64. It is noted that the tension thus obtained in the belt 32 is substantially a function of the resiliency of the safety guard 80 rather than the arbitrary discretion of the operator, and hence less skill is required by the operator. Further, it will be appreciated that tension is maintained on the belt 32 even though the diameter of the contact roller 28 is constantly changing during operation of the machine because of variance in the counter-force of engaging work-piece. In the event that the inner portion 14 is not in proper alignment with the outer portion 12 of the mounting member 10, the belt 32 will tend to slip off the rollers. Proper alignment is readily obtained by means of the adjusting screw 18.

As best seen in FIG. 3, the outer portion 12 has a bifurcated hub-like portion 88 at the outer end ther of. The contact roller 28 is mounted for rotation on the side of the hub-like portion. A tracer support member 90 is pivotally mounted for vertical motion between the forks 92 of the hub-like portion 88, as at 94. A tracer wheel 96 is rotatably mounted between forks 98 of the tracer suport member 90, as at 100. It will be appreciated that the tracer wheel 96 is mounted adjacent the contact roller 28 for engaging the surface of a workpiece. Means are provided for adjusting the position of the tracer wheel for adjusting the relative position of the contact roller with respect to the surface of the workpiece. This is done by means of a set screw 102 threadedly mounted on the hub-like portion 88 of the outer portion 12 for engaging the surface of the support member 90, as at 104. As best seen in FIG. 1, the contact roller 28 may be adjusted to grind the surface of the workpiece 106 as shown by the solid lines, or by manipulating the set screw 102 the contact roller 28 may be adjusted to grind the work surface 108 as shown by the broken lines in FIG. 1.

In this manner, the surfaces may be ground evenly and the amount of surface material removed or the depth of grinding can be accurately controlled.

As shown in FIGS. 1, 2 and 4, a pair of wheels 110 are rotatably mounted on the axle 112 which, in turn, is mounted on bracket 114. The mounting bracket 114 is a clamp-like member and is carried by the inner portion 14, and preferably is mounted on the air motor 46. As best seen in FIG. 1, the wheels 110 engage the surface of the work-piece 106 so that, in combination with the tracer wheel 96, the entire weight of the belt grinder is carried by the Work-piece, and hence reduces the physical effort required by the operator. The mounting bracket 114, FIG. 1, is arcuately adjustable so that the contact angle of the contact wheel 28 with respect to the surface 106 of the work-piece may be adjusted, as desired. In FIG. 1, the solid lines indicate one position of the wheels 110 wherein they engage the surface 106 of the work-piece, and the broken lines indicate a second position of the wheel wherein they engage the surface 108 of the work-piece. This is accomplished by releasing connection 116, arcuately rotating the mounting bracket 114 in a counterclockwise direction as viewed in FIG. 1, and thence resecuring-the connection 116.- As best seen in FIG. 1, the axle 112 may be adjusted in a direction transverse to the main longitudinal axis of the belt grind ing machine. That is, set screw 118 may be released to allow the axle 112 to slide withrespect to the bracket 114 until it is in its desired position. Then the set screw is tightened to lock the axle in its new position. This ad justment allows the machine to be used to grind surfaces adjacent walls or other obstacles.

, Referring to FIG. 5, the belt grinding and polishing machine may be provided with a contact roller 120 which is side mounted on an outerportion 121 and which is of very small diameter for penetrating hard to reach surfaces of certain workpieces.

.As best seen in FIG. 6, a contact wheel 122 is mounted between a pair of forked prongs 124 at the end of an outer portion 126..1t is particularly noted that the diameter of the wheel 122 is greater than-the distance between the forked prongs. This serves to allow the belt grinding machine to reach within acute angles on the surfaces work-pieces, or to reach inside small pipes. The forklike structure serves to provide structural support for heavy duty operation when the contact roller or wheel will run true and accurately.

Referring to the embodiment of the invention shown in FIG. 9, the belt sander further comprisesv a bracket 128 which is attached to the outer portion 12, the bracket 128 being mountable on the toolpost,130 of a lathe, indicated generally at 132. It will be appreciated that when the belt sander is mounted on the lathe 132 in the manner shown in FIG. 9, the endless belt 32 adjacent the wheel 128 engages the work-piece 134. This is for point contact grinding for rapid stock removal and size grinding.

In the embodiment of the invention shown in FIG. 10, the belt sander further comprises a bracket 136 which is connected to the air motor 46, and which is mounted on the toolpost 138, as at 140 of a lathe, indicated generally at 142. In the embodiment of FIG. 10, the portion of the endless belt 32 which is disposed between the roller 28 and the roller 54 engages the work-piece 144. That is, the polishing is done on the slack of the belt, immediately behind the contact wheel.

Although certain particular embodiments of the invention are herein disclosed for purposes of explanation, further modification and variations thereof, after study of this specification, will be apparent to those skilled in the art to which this invention pertains. Reference accordingly should be had to the appended claims in determining the scope of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. A belt sander of the class described for grinding or polishing the surface of a work-piece, the combination comprising a mounting member having an inner portion and an outer portion, a drive roller mounted on and carried by said inner portion, a second mounting member pivotally connected to said inner portion, a roller mounted on and supported by said second mounting member, a contact roller mounted on and supported by said outer portion, the outer surfaces of said rollers being adapted to support an endless belt thereagainst, means to cause tensioning of said belt, a tracer wheel mounted adjacent said contact roller for engaging said surface of the workpiece, said tracer wheel being mounted on a tracer support member and said tracer support member being pivotally mounted on said outer portion for vertical movement, means for adjusting the position of said tracer wheel for adjusting the relative position of said contact roller with respect to the surface of the work-piece.

2. A belt sander according to claim 1, wherein said tracer support member has a forked end and said tracer wheel is mounted therebetween.

3. A belt sander according to claim 1, wherein said means for adjusting the position of said tracer wheel comprises a screw member which threadedly engages said outer portion, and contacts said tracer support member for vertically positioning same.

4. A belt sander of a class described for grinding or polishing the surface of a work-piece, the combination comprising a mounting member having an inner portion and an outer portion, a drive roller mounted on and carried by said inner portion, a second mounting member pivotally connected to said inner portion, a roller mounted on and supported by said second mounting member, a contact roller mounted on and supported by said outer portion, the outer surfaces of said rollers being adapted to support an endless belt thereagainst, means to cause tensioning of said belt, a tracer wheel mounted adjacent said contact roller for engaging said surface of the workpiece, means for adjusting the position of said tracer wheel for adjusting the relative position of said contact roller with respect to the surface of the work-piece, said outer portion having a bifurcated hub-like portion at the outer end thereof, said contact roller being mounted on the side of said hub-like portion; and said tracer wheel being mounted on a tracer support member and said tracer support member being pivotally mounted between the forks of said hub-like portion for vertical movement; and said means for adjusting the position of said tracer wheel comprising a set screw threadedly mounted on said hub-like portion for engaging the surface of said support member for vertically positioning same.

5. A belt sander ofa class described for grinding or polishing the surface of a work-piece, the combination comprising a mounting member having an inner portion and an outer portion, a drive roller mountedon and carried by said inner portion, a second mounting member pivotally connected to said inner portion, a roller mounted on and supported by said second mounting member, a contact roller mounted on and supported by said outer portion, the outer surfaces of said rollers being adapted to support an endless belt thereagainst, means to cause tensioning of said belt, atracer Wheel mounted adjacent said contact roller for engaging said surface of the workpiece, means for adjusting the position of said tracer wheel for adjusting the relative position of said contact roller with respect to the surface of the work-piece, and wheel 7 means for supporting said belt sander with respect to said surface of a Work-piece when said belt sander is in its operative position.

6. A belt sander of a class described for grinding or polishing the surface of a Work-piece, the combination comprising a mounting member having an inner portion and an outer portion, a drive roller mounted on and carried by said inner portion, a second mounting member pivotally connected to said inner portion, a roller mounted on and supported by said second mounting member, a contact roller mounted on and supported by said outer portion, the outer surfaces of said rollers being adapted to support an endless belt thereagainst, means to cause tensioning of said belt, a tracer Wheel mounted adjacent said contact roller for engaging said surface of the work-piece, means for adjusting the position of said tracer wheel for adjusting the relative position of said contact roller with respect to the surface of the workpiece, and a pair of supporting wheels mounted adjacent said drive Wheel which in combination with said tracer wheel support said belt sander when in its operative position.

7. A belt sander according to claim 6, wherein said supporting wheels are mounted on an axle, said axle being mounted on said inner portion for transverse movement with respect to the longitudinal axis of said belt sander.

8. A belt sander according to claim 6, wherein said supporting wheels are mounted on an axle, said axle being mounted on said inner portion for arcuate movement substantially about the center line of said drive roller.

9. A belt sander of a class described for grinding or polishing the surface of a work-piece, the combination comprising a mounting member having an inner portion and an outer portion, a drive roller mounted on and carried by said inner portion, a second mounting member pivotally connected to said inner portion, a roller mounted on and supported by said second mounting member, a contact roller mounted on and supported by said outer portion, the outer surfaces of said rollers being adapted to support an endless belt thereagainst, means to cause tensioning of said belt, a tracer wheel mounted adjacent said contact roller for engaging said surface of the work-piece, means for adjusting the position of said tracer wheel for adjusting the relative position of said contact roller with respect to the surface of the work-piece, said outer member having a hub-like portion at the outer end thereof, said contact roller being mounted on the side of said hub-like portion, a tracer support member pivotally mounted on said hub-like portion for vertical movement, a tracer wheel rotatably mounted on said tracer wheel support member; said support wheels being mounted on an axle, said axle being mounted on said inner portion for transverse movement with respect to the longitudinal axis of the sander; said means for adjusting the position of said tracer wheel including a set screw mounted on said hub-like portion for engaging said support member for vertically positioning same.

10. A belt sander of the class described, the combination comprising a mounting member having an inner portion and outer portion, a drive roller mounted on and carried by said inner portion, a second mounting member pivotally connected to said inner portion, a roller mounted on and supported by said second mounting member, a contact roller mounted on said outer portion; the peripheral surface of said contact roller being contoured for engaging the inside surface of work-piece, the outer surfaces of said rollers being adapted to support an endless belt thereagainst, and a plate-like resilient shield member fixedly at one end to said inner portion and adapted to engage said second mounting member at the other end thereof to urge rotational movement of the second mounting member, said shield member being disposed between the second member and an operator when in normal operating position.

11. A belt sander of the class described for grinding or polishing the surface of a work-piece, the combination comprising a mounting member having an inner portion and an outer portion a drive roller mounted on and carried by said inner portion, a second mounting member pivotally connected to said inner portion, a roller mounted on and supported by the second mounting member, a contact roller mounted on said outer portion, the outer surfaces of said roller being adapted to support an endless belt thereagainst, a plate-like resilient shield member, means for fixedly connecting one end of said shield member to said inner portion, said shield member being adapted to engage said second mounting member at the other end thereof to urge rotational movement of the second mounting member, said shield member being disposed between the second member and an operator when in normal operating position, said shield member having a reducing cross-sectional area approaching said fixed connection for varying the resiliency force depending upon the degree of rotational movement of said second member.

12. A belt sander according to claim 11, wherein said means for fixedly connecting one end of said shield member to said inner portion comprises a first pin mounted on said inner portion and a space second pin mounted on said inner portion, said shield member extending from said second member to said first pin and substantially around said first pin and then to said second pin, said shield member engaging said first pin in a clamp-like manner.

13. A belt sander according to claim 11 wherein said reducing cross-sectional area of said shield member is tapered tongue shaped.

'14. A belt stander according to claim 11, wherein said reduced cross-sectional area of said shield member is a bifurcated fork having a V-shaped gap therebetween.

15. A belt sander of the class described for grinding or polishing the surface of a work-piece, the combination comprising a mounting member having an inner portion and an outer portion, a drive roller mounted on and carried by said inner portion, a second mounting member pivotally connected to said inner portion, a rotor mounted on and supported by said second mounting member, a contact roller mounted on said outer portion, the outer surfaces of said rollers being adapted to support an endless belt thereagainst, a plate-like resilient shield member fixedly connected at one end to said inner portion and adapted to engage said second mounting member at the other end thereof to urge rotational movement of the second mounting member, and means mounting said mounting member on a toolpost of a lathe with the portion of the endless belt disposed adjacent the contact roller engaging a work-piece for rapid stock removal.

16. A belt sander of the class described for grinding or polishing the surface of a work-piece, the combination comprising a mounting member having an inner portion and an outer portion, a drive roller mounted on and carried by said inner portion, a second mounting member pivotally connected to said inner portion, a rotor mounted and supported by said second mounting member, a contact roller mounted on said outer portion, the outer surfaces of said roller being adapted to support an endless belt thereagainst, a plate-like resilient shield member fixedly connected at one end to said inner portion and adapted to engage said second mounting member at the other end thereof to urge rotational movement of the second mounting member and means mounting said mounting member on a toolpost of a lathe with the portion of the endless belt disposed between the drive roller and the contact roller engaging a work-piece for polishing.

17. A belt sander according to claim 15, wherein said means mounting said member on the toolpost of a lathe comprises a bracket mounted on said inner portion, said bracket being removably attachable to the toolpost of the lathe.

References Cited UNITED STATES PATENTS 10 1,841,411 1/1932 Kux 51-143 3,212,218 10/1965 Sams et a1. 51174 FOREIGN PATENTS 584,162 10/1958 Italy.

OTHELL M. SIMPSON, Primary Examiner US. Cl. X.R. 51-148