US3218136A

US3218136A - Steel stake

Info

Publication number: US3218136A
Application number: US818876A
Authority: US
Inventors: Eric E Hogan; Robert S Malloch
Original assignee: HOGAN Co
Current assignee: HOGAN Co
Priority date: 1959-06-08
Filing date: 1959-06-08
Publication date: 1965-11-16
Anticipated expiration: 1982-11-16

Description

E. E. HOGAN ETAL STEEL STAK'E 4 Sheets-Sheet 1 Filed June 8, 1959 JNVENTORS l2/c E, Hoe/ew BY Roser Mmmm NQ MQ @n WKN NNN N ||\|lv N Ti" M.. w

free/V526 Nov. 16, 1965 E. E. HOGAN ETAL 3,218,136

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rroe/VEY- Nov. 16, 1965 E. E1 HOGAN ETAL Filed June 8, 1959 STEEL STARE 4 Sheets-Sheet 5 j ,74j j 4% W60 105 5f l0-9 Mqzzocf/ /QrroE/VEY.

STEEL STARE Filed June 8. 1959 4 Sheets-Sheet 4 155 loa 9.

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United States Patent C) 3,218,136 STEEL STAKE Eric E. Hogan and Robert S. Maloch, Riverside, Calif.,

assignors, by mesne assignments, to The Hogan Company, Riverside, Calif., a general partnership Filed June 8, 1959, Ser. No. 818,876 3 Claims. '(Cl. 29-193) This invention relates to steel stakes which are widely employed in setting up molds for casting concrete roads, curbs, Walks, foundations and the like.

It is a principal object of the invention to provide a superior stake for these purposes and a method and apparatus for economically producing such stakes.

While the preferred embodiment of the stake of the invention herein disclosed is round in cross section, it is to be understood that the principles of the invention are equally applicable to steel stakes made of any steel rod having a cross section formed by a regular polygon, the latter term being here used as including a square and a circle.

Prior to this invention, the points on most of the steel stakes of this class which were commercially produced, were formed either by a lathe operation or they were forged in a blacksmith shop. The points thus made varied in pitch. The high angle shorter points were less liable to being dulled or broken when driven into hardpan or shale but on the other hand offered much greater resistance to being driven, than the longer, sharper points.

Itis an object of the present invention to provide a steel stake having a point which is highly resistant to damage when driven into hard and gravelly earth but which may be driven with much less effort than the stakes previously provided for use in this kind of soil.

Another object is to provide such a stake which will have a notably higher resistance to wear than prior stakes employed in this service.

A further object is to provide a method and apparatus for producing a stake having the superior characteristics noted at a substantially lower cost than that of steel stakes formerly in common use.

The manner of accomplishing the foregoing objects as well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings in which FIG. 1 is a diagrammatic enlarged elevational view of the tapered and pointed section of a preferred embodiment of the stake of the present invention.

FIG. 2 is a diagrammatic illustration drawn approximately to scale of one of the steps in the method of manufacturing said stake.

FIG. 3 is a view similar to FIG. 2 and illustrates the terminal step in said method.

FIG. 4 is a plan View drawn approximately to scale of a preferred embodiment of the apparatus of the invention.

FIG. 5 is a front elevational view of FIG. 4.

FIG. 6 is a fragmentary rear elevational view of FIG. 4.

FIG. 7 is a fragmentary front elevational view of FIG. 4 illustrating the parts of the apparatus disclosed just following the tripping of the operation latch which sets od a cycle of operation of the apparatus.

FIG. 8 is a fragmentary plan view of FIG. 7 showing the rod gripping chucks being positioned and actuated to grip a rod at the beginning of a rod stretching operation.

3,218,136 Patented Nov. 16, 1965 Frice FIG. 9 is a view similar to FIG. S and shows the chucks of the apparatus as they are being separated with the jaws gripping the bar and the latter being stretched so as to separate this in the formation of a pair of pointed stakes.

FIG. l0 is a fragmentary diagrammatic sectional view taken on the line 10-10 of FIG. 9.

Referring specifically to the drawings and particularly to FIGS. 1, 2 and 3, a preferred embodiment 15 of the stake of the invention is shown in FIG. l which comprises a steel rod 16 having a tapered end section 17, the latter having a number of special properties which are invested therein by the method by which this is formed on said rod, and which will be pointed out hereinafter in connection with a description of the method of manufacturing stake 15.

The rod 16 is preferably formed of hot-rolled round rod of approximate 3A inch diameter. This rod may be of any regular polygonal cross section, however, and may even be square in cross section. The most economical rod to use in the manufacture of stakes 15, however, is the hot-rolled round rod, with a carbon content of ordinary mild steel or about 1020. A specially tough and durable stake 15, however, may be manufactured by ernploying a hot-rolled round steel rod with a carbon content of 1042.

The stake 15 of the invention is manufactured by a stretch forging operation which results in the tapered end section 17 of the stake 15 being shaped as shown in FIG. l. The base end of section 17 where it joins with rod 16 has the same diameter D as said rod and said section terminates at its outer end in a pointed tip portion 18 having a sharp point 19, the axial length and maximum diameter of said tip portion both being approximately 1/2 inch. The included angle of the surfaces of tip portion 18 adjacent the point 19 is preferably about 70.

Starting with this steep angular taper at the point 19 of the stake 15, sub-sections of the tapered section 17 disposed at progressively greater distances from the point 19 have angles of taper which progressively decrease from to 0. The angle of the tapered section 17 at the maximum diameter of the pointed tip portion 18 is preferably approximately 20. The rate of decrease of taper angle in the pointed tip portion 18 is thus seen to much greater than the rate of decrease per given unit of axial distance of the balance of the tapered section 17. In all portions of tapered section 17 however the rate of change of the angle of taper is harmonious. There are no sudden breaks in the angle of taper.

The harmonious merging of the relatively rapid change in the angle'of taper in the pointed tip portion 18 and the relatively slow rate of change of the angle of taper in the balance of the tapered section 17 and the harmonious merging of each axially selected sub-section of the tapered section 17 from axially adjacent sub-sections greatly facilitates the smooth penetration of the stake 15 into very hard and gravelly types of soil. The method by which the stake 15 is produced also results in the grain of the metal adjacent the surface of the tapered section 17 and to a substantial depth beneath said surface, converging on the point 19 harmoniously with the external surface of said tapered section so as to give lsaid tapered section exceptional resistance to abrasion. This resistance of course may be heightened by quenching and special heat treating operations.

.ae-raise The method of the present invention by which the stake is manufactured may be briefly described as embracing the steps of heating a section of particular length of a rod to a bright cherry red, gripping sections of said rod just beyond opposite ends of the heated section by a pair of chucks, and then rapidly separating said chucks along an axis in alignment with said rod, the speed of separation of said chucks preferably being at a maximum at the start of said separation and then rapidly decelerating just before the attenuation thus produced in the heated section of the rod comes to a conclusion with a separation of the rod in the formation of pointed ends on the separated portions as shown in FIG. 3.

The initial step of the method above briefly described involves providing such a rod of the desired crosssectional shape and diameter and which is preferably mild steel with a diameter of 3/4 inch and a length which is about 1% inches less than the combined length of the two stakes 15 to be formed from said rod.

Referring now to FIGS. 4 to 10 inclusive, the apparatus of the invention is there shown as preferably embodied in a rod pointing machine 30. This machine includes a heavy rail plate 31 which is about 3A inch thick, 6 inches deep and 3 feet long, and is supported at one end by a pair of

angle posts

32 and 33 secured to said plate by bolts 34, and at its other end by a pair of

angle legs

35 and 36 which are secured to said plate by a bolt 37.

Spacers

38 and 39 are disposed between the

legs

35 and 36 and plate 31 for a purpose to be made clear hereinafter. The

posts

32 and 33 extend straight downwardly from their attachment to the plate 31 and are welded to one end of a brace 40 which angles upwardly to where its opposite end is welded to the plate 31. The

legs

35 and 36 angle outwardly from their points of attachment with the plate 31 so that these legs combine with posts 32 to give a substantially triangular base of support to the machine 30. Welded on the rear face of the brace 40 is a main operating lever stop 41.

Welded at one end of an upper portion of angle post 33 and supported at its opposite end on the upper end of leg 36 by bolt 37 is a horizontal angle member 42. Mounted on member 42 adjacent post 33 by a plate 43 andbolts 44 is a hydraulic valve 45 having

pipes

46 and 47 connecting this respectively to a high pressure hydraulic pump (not shown) and to a liquid reservoir (not shown). The valve also connects with a hose through which liquid received through pipe 46 is discharged when valve 45 is actuated. This valve has an operating arm 49 the lower end of which is pivoted on the valve body and which connects pivotally with a valve plunger 50 which is normally spring urged inwardly yto neutral position by a spring (not shown) located on the interior of valve 45. When pulled outwardly by the swinging of arm 49 from the neutral position in which this is shown in FIG. 6 to the position in which it is shown in FIG. 7, the plunger 50 actuates valve 45 to close the port to line 47 and thus direct liquid, entering valve 45 from pipe 46, outward through hose 48.

Welded to the lower edge of plate 31 is a small bar 51 which extends forwardly and has a bearing 52 formed thereon to extend upwardly in front of said plate.

Welded onto the angle member 42 and extending upwardly therefrom is a valve operating rod guide 53. Welded to plate 31 at corresponding positions on opposite sides thereof are angle brackets 54 which rigidly support air cylinders 55 in horizontal positions parallel with said plate. These air cylinders are connected by pipes to an air hose 61 which leads to a compressed air reservoir (not shown).

Supported on rail plate 31 are a pair of rod chucks 62 and 63, the rst of which is stationary and the second of which is slidable on the plate 31.

Chuck 62 includes a heavy base plate 64 having lugs welded lthereon which extend downwardly therefrom lt on opposite sides of rail plate 31 and are united with said plate by a bolt 66.

The plate 64 has a rectangular notch 67 formed therein on the side facing the chuck 63 for a purpose which will be made clear hereinafter. Plate 64 also has holes for receiving bolts 63 to secure a front chuck jaw 69 to the base plate 64. law 69 is provided with parallel oblique slots 70 for receiving the bolts 6? whereby said jaw may be adjusted relative to plate 64 to accommodate rods of diiterent diameters in the machine 30.

The chuck 62 also includes a shiftable rear jaw 75 which is pivotally mounted on the front end of a lever '76, the latter being pivotally mounted by a bolt 77 on the base plate 64. The lever 76 is guided by a plate 78 which is secured to base plate 64 by bolts 79, suitable spacers 80 being disposed between the

plates

78 and 64. Mounted on the guide plate 78 is an adjustable stop screw 01. A horizontally apertured vertical lug 82 is provided on the rearwardly extending end of lever 76.

The shiftable jaw 75 has a plate 83 which overlies the front end of lever 76 and is pivotally secured thereto by a cap screw 84. The front end of lever 76 has a cylindrical face 35 which is concentric with screw S4 and tits a cylindrical recess 86 provided in the rear face of the jaw 75 so as to permit free rotation between jaw 7S and lever 76 while very high pressures are being transmitted by said jaw to said lever. law '75 is also provided with a pair of aligned tubular guides 90 and a serrated front face 91.

Shiftable chuck 63 includes a lbase plate 92 of the same size as base plate 64 excepting it does not have a notch similar to notch 67 in base plate 64. Welded to plate 92 and extending downwardly therefrom are guide plates '93 and 94 which have wear elements 95 welded to their right hand edges. Lower portions of

plates

93 and 94 extend below the lower edge of rail plate 31 and a spacer bar 96 is disposed between said lower portions of said plates and secured thereto by bolts `97.

Welded to the front face of guide plate 93 just above the level of bearing 52 is a cam latch lug 98. Welded on outer faces of both of the

guide plates

93 and 94 are brackets 99 on which are mounted plungers y100 which` are aligned with and slidably disposed in air cylinders 55 so as to make an air-tight fit therein. Pivotally mounted in bearing 52 is a rod` 105 having a collar 106, which rests against bearing 52, a control arm 107 bent upwardly from the left end of said rod and a latch arm 103 bent upwardly from the right end of said rod. A spring 109, coiled about said rod with one end connected to bearing 52 and the opposite end -to said rod, applies a constant torque to said rod swinging the control arm 107 against the front cylinder 55 and positioning the latch arm 108 in erect position in alignment with the cam latch lug 98.

Welded horizontally to the rear edge of base plate 92 are

sleeves

110 and 111, the latter being at a slightly higher level than sleeve 110, sleeve 110 being aligned with an aperture provided in valve operating rod guide 53. Sleeve 111 receives a bolt 112 an extending end of which is shaped to provide a latch release cam v113;

The base plate 92 has a pair of vertical holes for receiving bolts 114 for securing a front jaw 115 to plate 92. Parallel obliquely disposed slots 120 are provided in front jaw for receiving bolts 114 to permit the adjustment of this jaw relative to plate 92 for the same reasons that front jaw 69 is adjustably mounted on plate 64 of chuck 62.

Chuck 63 is also provided with a shiftable jaw 121 which -is a duplicate of jaw 75 and is pivotally mounted on the front end of a lever 122, the latter being secured to base plate 92 by a fulcrum bolt i123. The lever 122 is guided by a guide plate 124 which is spaced from plate 92 by spacers `125 and secured to said plate by bolts 126. The shiftable jaw 121 has aligned tubular guides 127 and a rod 130 is slidably received by these guides and the guides 90 ion shiftable jaw 75 to retain these jaws with a serrated j-aw face 128 on jaw 121 in substantial alignment with the corresponding jaw face 91 of jaw 75. The rear end of lever 122 is provided with a vertical apertured lug -129 which is aligned with the corresponding lug 82 on lever 76.

Extending through

apertured lugs

82 and 129 is a rod 135 which is threaded at opposite ends to receive nuts 136, this rod also carrying spacer sleeves 137 and coil springs 138 between said apertured lugs. A certain amount of play is left in the spacing of the nuts 136 at opposite ends of rod 135 so that when the

chucks

62 and 63 are loca-ted close together as shown in FIG. 8 the springs 138 expand to swing the

shiftable chuck jaws

75 and 121 inwardly into bar engaging positions, whereas, when the

chucks

62 and 63 are swung apart as shown in FIG. 4, the

lugs

82 and 129 are engaged by nuts 136 to swing the

levers

76 and 122 to withdraw the

chucks

75 and 121 from bar gripping relation with front jaws 69 and 1:15.

Slidale horizontally in the apertured valve operating rod guide 53 and sleeve 110 is a hydraulic valve operating rod l139 having a collar 140 fixed on one end portion of said rod and a forked yoke 141 provided at the opposite end of said rod which yoke receives the hydraulic valve operating arm 49 which is trapped in said yoke by a bolt 142 passing through said yoke. Also mounted on rod `139 is a collar 143 on which a hook latch 144 is pivotally mounted, the latter latch being yieldably held downwardly by a spring 145 connecting this with the rod guide 53, so that latch 144 normally rests against the rod 139 as shown in IFIG. 6.

Welded on the right hand end of rail plate 31 is a rod 150 having an adjustable collar 151 provided thereon on which is secured an end stop 152 for use in locating a rod in the machine 30.

Referring now to FIG. 10, there is a hole 153 provided in the rail plate 31 for receiving a bearing sleeve 154. Washers -155 are provided at opposite ends of said sleeve, and a spacer sleeve 156 is disposed between angle member 42 and the nearest of washers 155, this member being apertured to receive a bolt 157 which extends through the washers 155, the sleeve 154 and the spacer 156 so that when said bolt is tightened it forms a unit-ary assembly of the elements through which it extends. Disposed between the washers 155 and the rail plate 31 and suitably apertured to receive the sleeve 154 is a pair of bars 158. These bars have rounded upper ends 159 which extend into the rectangular recess 67 provided in chuck base plate 64 (see FIG. 7). The bars 158 straddle the diagonal brace 40 and the lower ends of these bars are welded together to form a main operating lever 160, An arm `165, on which is provided a counterbalance weight 166, is xed to the lower end of lever 160.

Disposed approximately parallel with the diagonal brace 40 and having a lug 167 extending between and pivotally mounted yby a pin 168 on the lower portions of angle posts 32 and 33 is a hydraulic cylinder 169 having a piston (not shown) connec-ting to a piston rod 170 which extends between the bars 158 of lever 160 and is pivotally mounted thereon by a pin 171. The hydraulic hose leading from the valve 46 connects with a lower end of hydraulic cylinder 169.

Operation The machine 30, comprising the apparatus of the invention, was designed specifically for carrying out the method of the invention which has been briefly described above. To do this, the two

chucks

62 and 63 are arranged so that they may be brought together as shown in FIG. 8 with a rod 25 extending through these chucks with the rod symmetrically disposed with respect to the plane separating the chucks and with the adjacent ends of the serrated faces 91 and 128 of

chuck jaws

75 and 121 separated approximately 4% inches as shown in FIG. 2.

6 The rod 25 before thus being inserted in the machine 30 has had a central section 175 thereof, about 4% inches in length, heated to a cherry red heat so that when the rod is inserted in the machine 30, the end portions of this heated section lie approximately in the same planes as the adjacent ends of the chuck jaws and 121.

The machine 30 then provides a means for separating the

chucks

62 and 63 with the rod 25 tightly gripped therein between the jaw 69 and jaw 75 (in the chuck 62) and the jaws 115 and 121 (in the chuck 63). This separation of the

chucks

62 and 63 is accomplished by movement of the chuck 63 in alignment with the rod 25 through the position in which this chuck is shown in FIG. 9 and which results in a stretching of the heated section 175 of the rod 25 to an extent which separates this rod to form two stakes 15 on each of which a tapered section is formed as shown in FIGS. l, 3 and 9. The operation of the machine 30 in this manner is accomplished as follows:

FIGS. 4 and 5 show the machine 30 at rest with the parts thereof in the positions to which they return at the conclusion of each operating cycle, and in which they remain until the machine is actuated to cause a new cycle to start.

When the parts of the machine are so positioned, the machine is rendered ready to operate by connecting the hose 61 with a reservoir of compressed air (not shown) so that the plungers of the cylinders 55 are constantly urged in a rightward direction by the air pressure in these cylinders, this tending to shift the chuck 63 in a rightward direction from the position in which this is shown in FIG. 5 to the position in which it is shown in FIGS 7 and 8. The hydraulic pump (not shown) which is connected to pipe 46 is also started to supply a relatively high volume of liquid under substantial pressure to the valve 45. With the machine at rest as shown in FIGS. 4 and 5 and with the valve operating arm 49 extending vertically upward as shown in FIGS. 4, 5 and 6, valve 45 is neutrally positioned allowing said liquid to freely return through pipe 47 to the liquid reservoir. At this time the chuck 63 is held in its retracted position shown in FIGS. 4 and 5 by engagement of the latch arm 108 with the cam latch lug 98 provided on said chuck. As previously noted, the constant torque applied to the rod by the coil spring 109 urges the arm 108 toward the chuck plate 93 thus retaining it in position behind the lug 98 until rod 105 is positively rotated by pulling outwardly on control arm 107.

The length of the stakes 15 which may be manufactured in the machine 30 varies, of course, and before starting to operate the machine in the manufacture of stakes, the rod end stop 152 is adjusted on the rod 150 and the collar 151 set on said rod with the stop positioned to centralize the rod 25 in the machine 30 when one end of this rod is placed against the stop 152.

A rod heating furnace is of course required in the commercial performance of the method of the invention but as this furnace may be any standard rod heating furnace with the fire opening adjusted to heat sections of the rods 25 as above described with these sections symmetrically located at midpoints in said rods, rio particular form of furnace is shown in the drawings. It is customary practice, however, to employ such a furnace with the bricks, confining the fire, spaced approximately 4% inches apart and with the rods 25 resting across the top of the bricks so that midsections of said rods approximately 4% inches long are exposed to the fire of the furnace. This opening of the furnace is preferably about a foot or more in length and a sutlicient number of rods 25 are rolled along the top of the brick to cover this opening with said rods. Each rod taken from the furnace to be inserted in the machine 30 is Withdrawn from one end of the tire opening above mentioned so that the cold rods are always added to the layer of rods overlying the furnace opening from the other end thereof. Each datalen rod thus withdrawn from the furnace has the midsection thereof heated to the desired temperature which is a bright cherry red and is the hottest of the rods overlying the furnace opening.

Having set up the furnace for continuously heating rods as above described and the hottest rod having been removed from one end of the furnace and inserted in the machine 3i) with the parts thereof at rest as shown in FIGS. 4 and 5 and with one end of this rod V25 engaging the rod stop 152, the operator merely pulls the control arm 107 outward from its engagement with the front air cylinder 55, thereby rotating the latch arm ldd out from in front or" the cam latch lug 9d. With the release of the shiftable chuck 63 from the restraint of the latch arm 16S, the compressed air in cylinders 55 rapidly shifts the chuck 63 from its open position shown in FlGS. 4 and 5 to its closed position shown in FlGS. 7 and 8.

As previously pointed out, the nuts 13o on opposite ends of rod 135 operate, whenever the chuck 63 is in open position as shown in FG. 4 to swing the arms 76 and ZZ about their

tulcrum bolts

77 and 123 to withdraw shiftable chucks 75 and ltll from gripping relation with a rod disposed between these jaws and jaws 69 and M5. With the

chuck jaws

75 and 121 thus in opened position, noV diiiiculty is experienced in inserting a bar 25 into the machine 30 or in withdrawing the stakes 15 from the machine 30 after said bar has been formed into such stakes. When the chuck 63 is shifted in the manner above described inwardly against the main operating lever intl and in closely juxtaposed relation with the chuck 62, as shown in FIG. 8, the springs 3138 are brought into operative relation with the levers 76 and i252 so as to shift the jaws and lZ into snug gripping relation with the bar 25.

The inwardk shifting of chuck 63 above described also brings the sleeve into engagement with the collar M0 on the hydraulic valve operating rod 139 so as to swing valve operating arm i9 from its upright position shown in FIG. 6 to its inclined position shown in FIG. 7. This closes the passage in said valve permitting liquid to dow from pipe 46 to pipe 47 and directs the liquid delivered under high pressure from the pipe 46 to said Valve through the hose d into the lower end of cylinder R69. This causes a rapid extension of the piston rod i7@ of said cylinder' from the full line position ot the piston rod to the broken line position thereof shown in FG. 5. The main operating lever lo@ of the machine is thus swung quickly from upright position to the broken line position in which this lever is shown in FlG. 5. in this movement of lever i60 the upper rounded end portions 159 of the bars E58 comprising said lever are brought to bear against the wear plates 95 provided on chuck 63 so as to very rapidly shift said chuck away from chuck 62 and return chuck 63 to its full open position, in which movement the cam latch lug 9S engages the latch arm lltiS, swings this outwardly so that the lug 9d moves lettward past the arm 19S and permits the latter to be spring urged inwardly behind said lug.

The valve operatingarm 49 is held in its inclined position shown in PIG. 7 during the action just described of the operating lever on shiftable chuck 63 by the riding ofy hook latch 3.4.4 over valve operating rod guide 53 when the rod 139, is shifted by engagement of sleeve il@ with collar ,1443 upon the closing movement of the chuck 63. The hook latch 144 thus holds onto the guide 53 and prevents the valve arm 419 changing position until the operating lever lle@ has been swung away from its full line position shown in FiG. 5 to its broken line position shown therein. During the culminating portion of the opening travel of the chuck 63 the latch release cam M3 provided on said chuck is brought into engagement with the hook latch 144 so as to litt this out of engagement with the rod guide 53, whereupon, the spring provided in the valve 45 acts upon the valve operating arm d@ to restore this to vertical position which reconnects pipe 47 with pipe 46 and hose d8 so that the weight of the counterbalance led is suiiicient to expel the liquid from the cylinder Eloi? along the hose 4S and outwardly through valve into reservoir line 47.

it is thus seen that with the return of the valve 45 to neutral condition and the trapping of the lug 98 behind the arm tu@ so as to hold the chuck 63 in expanded relation relative to chuck 62, the parts of the machine 36 are repositioned as these are shown in FiGS. 4 and 5 and a full cycle of operation of the machine 3G has been com pleted. As the jaws 75 and il21 of the chucks 62 and d3 are now swung outwardly as shown in FIG. 4 into non-gripping relation with the stakes l5 into which thek rod 25 has just been separated, these stakes are now readily lifted from the machine 39 and stacked.

While hot stretching of rod has been previously utilized in the manufacture of bullets, and hot stretching of fine wire employed for pointing electric vacuum tube iilaments, stakes made by the present invention embody features not anticipated by these prior operations, and these features have won unqualied preference for this product in the road and building construction industry.

First among these features is the fact that the point is protected from damage by its relative bluntness, whereas this bluntness is coniinedto a tip portion having a penetration frontal area which is less than one-half the penetration frontal area of the cross section of the body of the stake. Thus penetration by the tip portion is much easier to accomplish than is the case with ordinary stakes of the same degree of bluntness but which force into the soil the full penetration frontal area of the stakea relatively short distance after initial penetration of the point.

Another advantage found in stake l5 is the harmonious convex profile which smoothly merges each axially consecutive section of the tapered section thereof into immediately contiguous sections.

The alignment of the grain of the metal parallel with the surface throughout the section 17 thereof and to a substantial depth renders stakes l5 almost indestructible in comparison with stakes having points which are lathe formed or hammered out in a blacksmith shop.

Finally the stakes l5 can be and are being manufactured by the method of this invention at a small fraction of the cost of the stakes previously in general use in this tield.

We claim:

A steel stake provided to be driven downwardly into hard ground to aid in erecting concrete molds thereon, said stake comprising a steel rod of suitable length for this purpose and of a diameter D, said stake terminating at its lower end in a sharply pointed tip portion, the axial length and the upper and maximum diameter of which are each approximately 2/ 3D, said stake having a gradually tapering portion, about 4D in axial length located immediately above said tip portion, the upper and maximum diameter ot said tapering portion being l) and its lower and minimum diameter being the same as the upper and maximum diameter of said tip portion.

2. A steel stake as recited in claim l wherein the pointed extremity of said tip portion has an included proiile angle of approximately 70, and in which the profile angle of said tip portion gradually decreases above said pointed extremity so that said tip portion harmoniously merges with the aforesaid gradually tapering portion of said stake as shown and described.

3. A steel stake as recited in claim l wherein the form of said stake recited is derived from a hot stretching operation, and the grain ot the metal in the interior of said tip portion and said tapering portion thereby converges symmetrically with the axis of said stake and with the external surfaces of said stake portions to meet at the point ot said stake.

(References on iollowing page References Cited by the Examiner UNITED STATES PATENTS Thomas 256-34 Davis 256-34 Murphy 29-185 Baird 256-34 Lloyd 256-34 Stevens 225--101 Hart 29-5'52 Mansfield 29-4185 Denning 256-34 Menking 29-197 Nuerburg 29-193 Atkinson 119-121 Willett 225--101 Rendleman 29--193 Anderson 29-552 FOREIGN PATENTS Great Britain.

10 DAVID L. RECK, Primary Examiner.

WHILTMORE A. WILTZ, HYLAND BIZOT,

Examiners.

Claims

1. A STEEL STAKE PROVIDED TO BE DRIVEN DOWNWARDLY INTO HARD GROUND TO AID IN ERECTING CONCRETE MOLDS THEREON, SAID STAKE COMPRISING A STEEL ROD OF SUITABLE LENGTH FOR THIS PURPOSE AND OF A DIAMETER D, SAID STAKE TERMINATING AT ITS LOWER END IN A SHARPLY POINTED TIP PORTION, THE AXIAL LENGTH AND THE UPPER AND MAXIMUM DIAMETER OF WHICH ARE EACH APPROXIMATELY 2/3D, SAID STAKE HAVING A GRADUALLY TAPERING PORTION, ABOUT 4D IN AXIAL LENGTH LOCATED IMMEDIATELY ABOVE SAID TIP PORTION, THE UPPER AND MAXIMUM DIAMETER OF SAID TAPERING PORTION BEING D AND ITS LOWER AND MINIMUM DIAMETER BEING THE SAME AS THE UPPER AND MAXIMUM DIAMETER OF SAID TIP PORTION.