Locking device for excavating tooth
US 3126654 A
Description (OCR text may contain errors)
March 31, 1964 P. EYOLFsoN ETAI. 3,126,654
LOCKING DEVICE FOR EXOAVATING TOOTH Filed July 18. 1961 2 Sheets-Sheet 1 March 31, 1954 P. EYoLFsoN ETAL 3,125,654
LOCKING DEVICE FOR ExOAvATING TOOTH Filed July 18. 1961 2 Sheets-Sheet 2 United States Patent O "ce 3,126,654 LCKING DEVICE FOR EXCAVATING TTH Paul Eyolfson and Nerval T. Grubb, Portland, Greg., and
.Iohn I. Meece, Denver, Colo., assignors to Esco Corporation, Portland, Greg., a corporation of Oregon Filed .Iuly 18, 1961, Ser. No. 124,852 9 Claims. (Cl. .S7- 142) This invention relates to a locking device for an excavating tooth which has utility in a wide variety of earthhandling implements, viz., drag line buckets, dippers, trenchers, etc.
This application is a continuation-in-part of application Serial Number 723,057, filed March 21, 1958, now abandoned.
Excavating teeth, for the most part, are provided as two pieces-an adapter for mounting on the excavating implement or machine, and a Wedge-shaped point removably mounted on a projecting nose portion of the adapter. The point can thus-be replaced from time to time for sharpening, or Where the character of the excavation requires a different contour of cutting edge. Because of this, a wide variety of locking pins or keys have been employed in the past to releasably lock the point on the adapter nose.
Two conflicting attributes must characterize the locking device. First, the locking device must be capable of withstanding the forces tending to disengage the point from the adapter. The importance of this is manifest should the relatively hard point become accidentally detached during a digging operation, the relatively softer adapter could be rapidly destroyed or distorted, making necessary extensive and expensive repairs to a valuable implement. Second, the locking means must be readily disengageable itself so as to facilitate the interchange of points.
These two attributes have been only imperfectly realized in the past, reconciliation or compromise having been necessary. The engineers utilizing excavating machines were forced to choose from a variety of different key locks. If the chances of accidental loss of the point were great, a radically deformed pin might be used which made the point replacement a ditlicult and time-consuming operation. If, on the other hand, the risk of point loss seemed small, a readily removable pin would be used. However, the actual practice never seemed to iit into either category-earth or rock which seemingly dictated the choice of one or the other of the locking mechanisms might suddently change radiaclly in character so as to vitiate the effectiveness of the originally-chosen locking means.
A principal object of this invention is to provide a locking structure for an excavating tooth that avoids the shortcomings and drawbacks outlined above-particularly in that it provides maximum locking power against point disengagement forces while being readily removable so as to permit point detachment from the associated adapter.
Another object is to provide a novel locking device for an excavating tooth wherein the locking device is characterized by increased locking power when the composite tooth is under stress tending to dislodge the point from the nose-increased over and above the locking power obtained while the composite tooth assembly is at rest.
Still another object is to provide an improved locking device for the point and adapter elements of an excavating tooth wherein the locking device is characterized by a uniquely corrugated-type surface that serves as a stressbearing or receiving surface to facilitate the dispersal of forces tending to upset the desired assembly and remove the point from the adapter.
3,126,654 Patented Mar. 3l., 1964 Yet another object is to provide a novel tooth assembly wherein a point, adapter, key and locking member all cooperate in a unique fashion to provide exceptional resistance to forces tending to separate the various tooth components but which, at the same time, is readily amenable to disasssembly when required. Other objects and advantages may be seen in the details of construction and operation set down in this specification.
The invention will be explained in conjunction with the accompanying drawing, in which:
FIG. l is a perspective view, partially broken away, of an excavating tooth incorporating features of the invention;
FIG. 2 is a top plan View, also partially broken away, of the composite tooth of FIG. l;
FIG. 3 is an enlarged scale sectional view of the locking portion of the structure of FIG. 1 and as would be viewed along the sight line 3-3 as applied to FIG. 1;
FIG. 4 is an enlarged sectional view, in fragmentary form, as would be viewed along the line 4 4 of FIG. 3;
FIG. 5 is a sectional View, taken along the line 5 5 of FIG. 4;
FIG. 6 is a fragmentary sectional view of a modified form of the invention, corresponding to the showing of FIG. 4;
FIG. 7 is an enlarged sectional view corresponding to the showing in FIG. 5;
FIG. 8 is an elevational view of the plug portion of the key lock;
FIG. 9 is an end elevational view of the plug of FIG. 8;
FIG. 10 is an elevational view of the key portion of the lock; and
FIG. 11 is an end elevational view of the key of FIG. 10.
In the illustration given, and with particular reference to FIG. l, the symbol A designates generally an adapter provided as part of the composite tooth generally designated 10. The symbol B designates generally the point portion, While the symbol C designates a wear cap. The numeral 11 designates a locking pin or key, while the numeral 12 designates a key lock member.
The adapter A is equipped with a rearwardly-extending shank 13 suitably slotted as at 14 for attachment to the lip or other portion of an excavating device (not shown). The forward portion of the adapter A terminates in a Y nose 15, which is essentially wedge-shaped, being dened in part by wedge surfaces 16 (the upper one of which only is designated in FIG. 1). In the illustration given, the nose 15 terminates in a generally box-shaped apex 17, which is described in greater detail in the co-owned, co-
v pending application of Paul V. Larsen, et al., Serial No.
50,655, tiled August 19, 1960. Reference to that case may be had for additional details of construction not set forth herein.
Further characterizing the interconnected nose 15 and point B, the surfaces 16 of the nose 15 and the confronting surfaces 18 of the socket generally designated 19 of the point B, may have a conical shape of the character described in detail in U.S. Patent No. 2,919,506.
The point B is seen to be essentially symmetrical about a midplane passing through the tip 20 of the point B and thus the point B is reversible to equalize wear on the upper nand lower sides thereof. Wear on the upper portion of the adapter A is minimized through the provision of the Wear cap C, which is equipped with a tongue 21 slidably received within a groove 22 provided in the upper surface of the adapter A, all of which can be seen in greater detail by reference to the coowned, copending application of George W. Hill, Serial No. 52,176, filed August 26,
Reference to FIG. 4 illustrates the locking structure employed for securing the adapter A and point B together.
For the purpose of installing the key 11, the point B is equipped with upper and lower key-receiving, aligned openings 23. The adapter A is equipped with a vertically-extending opening 24 which is enlarged in the direction of the tip as at 24a (see FIG. 2) to provide a chamber for the receipt of the lock member 12. It will be seen that the recess 24 is thus longitudinally enlarged relative to the openings 23 and in the direction of the tip 20. The enlarged opening 24 (including the portion 24a) extends between the surfaces 16, as also can be appreciated from FIG. 4.
The lock member 12 is preferably constructed of molded rubber and has mounted therein a plurality of metal inserts 25. Comparison of FIGS. 4 and 5 reveals that the inserts are essentially hollow cylinders and are positioned, i.e., embedded, within the body of the rubber lock member 12 in such a fashion as to project partway from the otherwise essentially planar surface 12a which confronts the key 11.
The key 11 is seen to be equipped with a corrugated surface 11a made up of projections 26 and recesses 27 corresponding to the contour developed by the inserts 25 and the remaining planar surface 12a of the lock 12. It will be noted, particularly from a consideration of FIGS. 1 and 4, that the key 11 is symmetrical about a transverse plane, i.e., the plane of symmetry of the point B, which facilitates the insertion of the key 11 from either the upper or lower openings 23.
In the operation of the tooth 10, the adapter A is initially installed on a dragline bucket, dipper, etc. by virtue of a suitable locking key in the slot 14. Alternatively, the adapter itself may be welded to the lip of an excavating implement. Thereafter, the lock 12 is mounted within the chamber 24a of the adapter nose 15. Because of the resiliency of the rubber lock 12, it can maintain this position notwithstanding the absence of a bottom support-by virtue of a temporary press lit with the shoulders 24b of the slot or opening 24 (see FIG. 4). The point B is installed on the adapter nose as by moving the point B along the plane of symmetry and to a position wherein the point openings 23 are aligned with the nose opening 24. Thereafter, the key 11 can be installed through either of the point openings, as desired, and this compresses the lock 12 to relieve the bearing against shoulders 24h.
In an excavating operation, as where a force F is applied downwardly on the tip of the point B, the pressure or stress is translated through the top of the pin through the top corrugation 26a (see FIGS. 1 and 3). This in turn transfers force through the rubber lock 12 to all the other corrugations so that a relatively uniform pressure is maintained all along the mating surfaces. Thus, all inserts and/or corrugations are doing their full share of the work. When a reverse force is applied, the mechaanism works in the same manner, starting with the bottom corrugation. It appears important that the stresses be transmitted through the corrugating surfaces which act as primary bearing areas, insuring positive locking without displacement of the key 11. Opposed to this, the prior art locking mechanisms did not function until some force acted to eject the locking pin, and only then if manufacturing tolerances were carefully maintained. In the instant case, all that is required is to have the key 11 under pressure to provide a positive engagement of the various corrugations.
In the specific illustration given, the diameter of the cylindrical inserts 25 is of the order of 7/16, with the projection of the inserts 25 being about g" forwardly of the surface 12a. The amount of the projection may vary somewhat, going as high as 9/16", but preferably the projection should lie within the range of 20-45% of the insert diameter, and optimum performance is achieved when about 35% of the diameter of the insert 25 is bonded within the body of the lock 12thus avoiding stripping of the inserts 25 from the lock 12 when the key 11 is driven into place. The rubber lock 12 is advantageous in that it allows independent movement of each steel insert 25, resulting in a hydraulic action of the rubber under stress. This action forces each insert to assume a perfect mating position with the corrugations in the key 11, irrespective of imperfections in manufacture, thus assuring full depth contact in each key corrugation. Although the inserts 25 are shown in FIG. 4 to be fully embedded within the lock 12, the rubber facing is actually only a few thousandths of an inch thick over each insert, and usually strips off the first time the key 11 is inserted. Thus, it will be appreciated that the lock 12 is essentially steel faced, and a modification of the invention showing this feature is seen in FIG. 6. In FIG. 6, the locking key is designated by the numeral 111, while a steel facing plate is designated by the numeral 125. The plate and the key 111 are equipped with mating corrugations, and the plate 125 is urged into place by virtue of a resilient block 112 interposed between the plate 125 and the nose 115. The one-piece steel corrugated faced plate 12S has the same hydraulic rubber action as far as maintaining equalized pressure along the entire length of the mating surfaces, as does the embodiment of the invention seen in FIG. 4.
The number of corrugations employed in the cooperating lock mechanism and key depends to a certain extent upon the size. It has been found advantageous to use as few as two inserts 25 in smaller plugs or locks 12, and as many as ve or six in the larger plugs, corresponding to the larger excavating teeth.
In the illustration given, the plug or lock 12 or 112, as the case may be, is placed forwardly of the key, i.e., in the direction of the tip 20, and thereby eliminates metal-to-metal contact between the key and the nose, forcing the resilient block 12 or 112 to act in resisting negative thrust which may develop and tend to unseat the point B from the nose 15. The block 12, in resisting negative thrust, applies greater pressure on the corrugations and/or inserts and thereby increases the locking pressure. From this, it can be seen that all Working forces on the point tending to dislodge the point from the adapter act to increase the locking power of the key and plug over and above the locking power obtained while the assembly is at rest, and the multiple corrugations distribute this locking power uniformly over the entire bearing surface.
As best seen in FIG. 4, the key 11 is slightly recessed as at 11b, which results in the development of lug portions 11c adjacent the top and bottom ends of the key 11 and which bear against the Walls of the point openings 23-thereby achieving the avoidance of metal-to-metal contact between the key and the nose. Also the key is forwardly tapered as at 11d to avoid any engagement with the shoulders 24b.
While in the foregoing specification a detailed description of the invention has been given for the purpose of explanation thereof, many variations in the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.
1. In combination, a generally wedge-shaped point having a socket with aligned key-receiving openings communicating with said socket, an adapter equipped with a wedge-shaped nose adapted to have said point mounted thereon with said nose in said socket, a key-receiving opening in said nose aligned with the point openings, said nose opening being enlarged relative to said point openings and in a direction longitudinally of said nose to provide a lock chamber positioned forwardly of a key mounted in said point and nose opening, an elongated rigid key removably mounted in said point and nose openings and having a surface confronting said chamber, an elongated resilient lock in said chamber equipped with a surface engaging said key surface, said lock surface being equipped with longitudinally spaced-apart projections, each of said projections including a rigid insert, said key surface being contoured to mate with said lock surface, said chamber being equipped with inwardly-extending shoulders to provide a temporary press lit with said lock during assembly of said point on said adapter.
2. The structure of claim 1 in which said key is equipped with side surfaces tapering toward said confronting surface, whereby said key is insertable free of engagement with said shoulders.
3. In combination, a generally wedge-shaped point having a socket with aligned key-receiving openings cornmunicating with said socket, each of said openings being adapted to receive a locking key, an adapter equipped with a wedge-shaped nose adapted to have said point mounted thereon with said nose in said socket, a keyreceiving opening in said nose aligned with the point openings, said nose opening being enlarged relative to said point openings and in a direction longitudinally of said nose to provide a lock chamber positioned forwardly of a key mounted in said point and nose openings, an elongated key removably mounted in said point and nose opening and having a surface confronting said charnber, an elongated lock in said chamber equipped with a surface engaging said key surface, said lock surface being equipped with longitudinally spaced-apart projections, said key surface being contoured to mate with said lock surface, said lock chamber being accessible from either end prior to the installation of said point on said adapter with said point closing the ends of said chamber when said point is installed on said adapter, and means on said adapter for supporting said lock prior to installation of said point on said adapter.
4. In combination with a base nose and socket-equipped, wedge-shaped point releasably engaging said nose, said point and nose being provided with aligned key-receiving openings, said point having a digging edge and said aligned openings extending generally transversely to the point midplane passing through said edge,
an elongated key extending through said openings and provided with forward and rear surfaces, one of which is a corrugated surface providing at least two identical transversely-extending, successive projections and recesses,
said corrugated surface being located in the portion of said key positioned within said nose opening,
a key lock member within said nose opening and provided with a corrugated surface mating with the corrugated surface of said key, said member corrugated surface comprising a plurality of identical projections, each projection being equipped with a rigid insert,
said key being free of projections and recesses in the end portions thereof positioned in said point openlngs,
the common tangent to the key projections being parallel to the central longitudinal portion of the other of said key surfaces, whereby said key is insertable and removable through either of said point openings. f
5. The structure of claim 4 in which said key is equipped with end surfaces angularly related to each other to conform to the wedge shape of said point.
6. In combination with a nose-equipped adapter and a socket-equipped, wedge-shaped point providing a forward tip, said nose and socket being generally wedgeshaped, with the nose being removably positioned in said socket, said point and nose being equipped with aligned openings providing a vertically-extending, keyreceiving passage, said point openings communicating with said socket, said nose opening being enlarged relative to said point openings in the direction of the tip of said wedge-shaped socket,
an elongated key extending through said openings and provided with forward and rear surfaces, with the forward surface being a corrugated surface providing at least two transversely-extending, identical successive projections and recesses, said corrugated surface being located in the portion of said key positioned within said nose opening, and a resilient key lock member within said nose opening and provided with a corrugated surface mating with the corrugated surface of said key, said member corrugated surface comprising a plurality of identical projections, each projection being equipped with a rigid insert,
the common tangent to the key projections being parallel to the central longitudinal rear surface of the key, whereby the key is insertable and removable through either of said point openings.
7. The structure of claim 6 in which said key is symmetrical about the tooth midplane passing through said tip.
8. For an excavating tooth having a coacting nose and point, with the point being releasably mounted on said nose, aligned openings in said point and nose for the receipt of a key to releasably lock the point and nose together, an improved locking key, comprising:
an elongated rigid body having longitudinally-extending front and rear surfaces, with said front surface having a corrugated portion providing at least two parallel projections and recesses, said projections and recesses being arranged transversely of the key length, said corrugated portion being positioned centrally of the length of the key and terminating short of the ends thereof, the common tangent to the projections being parallel with the central portion of the rear surface, the end surfaces of said key being rearwardly divergent, said key being transversely constricted throughout its length adjacent said forward surface.
9. For an excavating tooth having a coacting nose and point, with aligned openings in the nose and point and a locking key extending through said aligned openings, an improved key lock for mounting in said nose opening and for engagement with said key, comprising:
an elongated, block-like body constructed of resilient material and having front and rear surfaces, said rear surface being adapted to engage said key, said rear surface comprising alternating coplanar surfaces and transversely-extending, rigid projections, each of said projections being partially defined by a metal cylinder embedded in said body, about 25- 40% of each of said metal cylinders projecting from the plane of the planar surfaces, the end surfaces of said body being forwardly convergent.
References Cited in the file of this patent UNITED STATES PATENTS 212,497 Perry Feb. 18, 1879 692,274 Gumaer Feb. 4, 1902 1,385,743 Ellert July 26, 1921 2,238,463 Dubilier Apr. 15, 1941 2,427,651 Baer Sept. 23, 1947 2,772,492 Murtaugh Dec. 4, 1956 2,846,790 Davis et al. Aug. 12, 1958 2,899,242 Bombardier Aug. 11, 1959 2,921,819 Rifkin Ian. 19, 1960 2,949,687 Peklay et al Aug. 23, 1960 2,982,035 Stephenson May 2, 1961 2,990,634 Eyolfson July 4, 1961 FOREIGN PATENTS 23,019 Great Britain 1907 213,291 Australia Feb. 25, 1958