US2332628A - Scraper latch - Google Patents

Description

Oct. 26, 1943.

H. c. FRENCH 2,332,628

S CRAPER LAT CH Filed Nov. 17, 1941 2 Sheets-Sheet 1 INVENTOR.

x-fi s fi m H. C. FRENCH SCRAPER LATCH Oct. 26, 1943.

Filed NOV. 17, 1941 2 Sheets-Sheet 2 AT TORNEY's.

Patented Oct. 26, 1943 scaarna m'rcn Henry 0. French, Elm Grove, Wia, assignor to The Hell 00., Milwaukee, Wis., a corporation of Wisconsin Application November 17, 1941, Serial No. 419,377

2 Claims. (Cl. 37-126) provide a scraper latch, effective relative to bowl raising mechanism, which is automatically operated when the scraper bowl moves to and from certain positions.

A further general object of the invention is to provide latch mechanism for insuring retention of a scraper bowl in a desired elevated position and which takes the load oil of the scraper bowl operating mechanism or instrumentalities.

Certain forms of scrapers, particularly of the so-called dig and carry type, have articulated front and rear wheeled frames carrying bowl and gate members. Due to the articulation as between the wheeled frames, and the mounting of the bowl and gate members, when the bowl is in elevated or load carrying position the main operating mechanism must be employed and kept under power for the purpose of retaining the bowl in said elevated position, thereby imposing undesirable strain on such mechanism.

With the above in mind, a more specific object of the present invention is to provide a latch mechanism as between certain relatively movable elements of a scraper which are brought into juxtaposition when the bowl is elevated, such latch mechanism being effective to hold the bowl in elevated position and taking the strain and load oil of the means employed for raising the bowl.

The undesirable strain and load on a scraper bowl operating mechanism is also pronounced in an articulated frame scraper wherein a beam, hingedly associated with the frame structure, is releasably retained in a lowered or down-swung position when the scraper bowl iselevated, it being usual to provide with an arrangement of this type, cables for operating the bowl mechanism extended over the free end of the beam,

together with cables between a fixed frame part and the outer end of the beam. With this form of structure, the cable between the fixed frame portion and the outer end of the beam is ordinarily reeled in and held taut by a winch when the beam is in a down-swung position with the bowl raised, whereby the taut cable holding the beam in the down-swung position is under severe strain and tension and is solely responsible. for

holding the scraper bowl in elevated load confining position. The present practice is. to operate scrapers at relatively high speeds, particularly when'carrying material in the closed and elevated bowl, and a scraper constructed as last described, while travelling at a relatively high rate of speed would be severely damaged if the tautbeam cable should snap or break, thereby releasing the down-swung beam and permitting the bowl assembly to drop and contact the ground.

It is a further specific object of the present invention to overcome the last mentioned objections and difliculties by providing a cable operated, beam equipped scraper with automatically operating latch mechanism as between a fixed scraper frame part and the movable beam, whereby the latch constitutes the sole means for releasably holding the beam in a desired effective position, relieving strain and load on the beam controlling cable and permitting the scraper operating cables to be slack while the scraper is travelling and transporting material.

A further specific object of the invention is to provide a scraper latch which automatically latchingly engages a complementary element during the normal operating movement of the scraper beam to bowl raising position, and which is automatically manipulated to releasing position by an additional movement of the beam followed by the normal operating movement of the beam to bowl lowering position.

A further object of the invention is to provide a scraper latch with which a; scraper may be readily equipped with a minimum of parts and modifications.

A further object of the invention is to provide a scraper latch which is of very simple construction, is efficient and automatic in operation, is strong and durable, is inexpensive, and is well adapted for the purposes described.

With the above and other objects in view, the invention consists of the improved scraper latch and its parts and combinations as set forth in the claims, and all equivalents thereof.

In the accompanying drawings in which the same reference characters indicate the same parts in all of the views:

Fig. l is a side view, slightly in perspective, of a cable operated scraper equipped with the improved latch mechanism, attached to a tractor which furnishes the motive power for the scraper;

Fig. 2 is an enlarged central longitudinal vertical sectional view through a scraper equipped with the improved latching mechanism showing the parts in load confining and transporting beam element from the latch; and

Fig. 5 is an enlarged fragmentary detail view, with parts broken away and in section, showing the latch in operative position with a dotted line showing of the latch in a releasing position.

While the invention is herein disclosed in connection with a specific form of beam equipped, cable operated scraper, it should be understood that this is merely by way of illustration, and the invention is notto be limited thereto. ,4

Referring now more particularly to thefl rawings, the improved scraper shown therein" y way of illustration, comprises in general a sturdy front frame 8 transportable by and swingably supported upon a front wheel supported carriage 9. This front frame also has laterally separated rearwardly and downwardly extending integral side arms I0. There is also a sturdy rear frame transportable by and swingably mounted upon a rear wheel supported carriage |2 having laterally separated, forwardly extending, integral opposite 'side walls l3 disposed between the rear ends of the front frame arms l and rigidly interconnected by means of a curved rear wall |4 having upper and lower cross beams l5 and I6 respectively associated therewith, together with front cross beams I! and I8 located forwardly of the wall |4 to provide an open bottom. Alined pivot pins |9 articulably interconnect the rear ends of the front frame arms II) with the medial outer portions of the rear frame side walls l3 whereby a jack-knife action of the frame is attainable, permitting raising and lowering of the load carrying bowl structure as will hereinafter appear.

The load carrying bowl structure includes a fiat load supporting bottom plate 20 pivotally suspended at its forward end, by means of a pivot shaft 22, from the front lower cross beam I1 in close proximity to a transverse scraper or cut-- ting blade 2| which is carried by said beam H. The bottom plate 20 has its rear end engageable with lugs 23 secured to the lower rear beam l6 and is swingable upwardly along the curved rear wall I4 and said plate 20 also has a bracket 24 rigidly attached to its medial portion.

The front end of the bucket is controlled by a load confining apron or front gate'25 having integral opposite curved side arms 26 disposed between and swingably suspended from the side walls l3 of the rear frame II by means of alined pivot pins 21. Said front gate 25 has its lower cut off edge 28 cooperable with and swingable beneath the cutting edge of the blade 2| to confine material 29 within the space bounded by the walls l3 and I4 above the bottom plate 20, which is in effect the scraper bucket.

At the forward end of the mechanism there is a bowl lift beam 30 which is swingably suspended from the front frame 8 by means of a pivot shaft 3|. When the scraper frame elements articulate for raising and lowering movements ofthe bowl. I

the bowl lift beam 30 moves to and from a downswung position such as is shown in Figs. 1 and .2 of the drawings, The beam 30 has its rear end connected to the medial portion of .the upper front cross beam l8 by a set of links 32 and pivot 5 pins.

The mechanism for effecting swinging of the front gate 25 and of the bottom plate 29 comprises a single cable 31 which first raises the front gate 25 and subsequently tilts the bottom plate 20 to discharge the load. Details of the sheaves, cables and other mechanism in connection with the gate 25 and bottom plate 20 will not be described in detail as they are similar to that shown and described in my Patent No.

Re. 21,885. Suffice it to say that a pull on the cable 31 will first elevate the front gate 25 and will thereafter swing the bottom plate upwardly, while release of the pull on the cable 31 will permit gravity to first lower the bottom plate 20 20 and thereafter lower the front gate 25.

Mounted upon the forward swinging end of the bowl lift beam 30 is a set of alined sheaves 38 which are joumalled on a shaft 39. The forward upper portion of the front frame 6 carries a shaft 40 upon which is mounted another set of sheaves 4|. The cable 31 for actuating the gate 25 and bottom plate 20 passes under a floating sheave 42, coacts with one of the sheaves 38 and one of the sheaves 4|, and then extends forwardly between certain guide rollers 43 to a hoisting winch 44 located on the rear of a propelling tractor 45.

The mechanism-for permitting articulation between the front and rear frames 8 and II about the pivot shafts I9, thereby effecting raising and lowering movements of the bowl assembly, comprises a second cable 46 which extends rearwardly from the tractor winch 44, and after passing between certain of the guide rollers 43 this cable 46 passes successively about the sheaves 4| and 38 and finally has an end secured to a cable connector 41 mounted on the beam 30. With the arrangement described, when a pull is exerted on the cable 46, the beam 30 will be swung about its pivot shaft 3| from the position shown in Fig. 3 to a down-swung position similar to that'shown in Figs. 1, 2 and 5, thereby swinging the frames 8 and II relative to each other about the pivot shafts l9 and elevating the cutting blade 2|,

50 which in effect constitutes a raised position of the bucket structure. When the pull on the cable 46 is released. gravity acting upon the rear frame II and associated parts, together with the weight of the material 29, will cause the scraper blade 2| to lower more or less toward the ground. This action will also tend'to swing the front end of the bowl lift beam 30 from the position of Figs. 1 and 2 to an upwardly directed position. Such movement of the beam and consequent moveunless the bowl lift beam 30 is released and is permitted to freely move to the upwardly directed position. The cable 31, which actuates the front gate 25, engages certain of the sheaves 36 and 4|, one ofwhich'is carried by the swinging beam 30. Hence,the gate 25 will also be affected by raising and lowering the cutting blade 2| independently of its operation by the cable 31. Thissecondary movement of the gate 25 is such that the material 29 will be most effectively retained within the =bucket structure as the blade 2| is raised and lowered.

thus fargiven it is evident that when the cable 46 is reeled in by the tractor borne winch 44,

ment of the bowl structure is not permissible From the description of the scraper mechanism such reeling in of the cable will exert a downward pull on the outer end of the beam 30, causing the beam to move from an upwardly directed position to the down-swung position of Fig. 2.

This operation of reeling in the cable 46 and lowering the beam 30 materially reduces the distance between the sheaves 38 and 4| so that the cable extents connecting the sheaves 38 and 4| are materially shortened. In prior structures it was necessary, in order to retain the beam 3|! in said lowered position, to keep the winch or other power instrumentality under operation or to set the winch brake so that the cable 46 is maintained in its shortened relationship and is taut as between the winchand sheaves 4i and as between the sheaves 4| and 38. This position of the beam 30 is the beam position when the bowl mechanism is elevated, as previously described, for load transporting purposes. Present day practice is to run scrapers at a relatively high rate of speed in transporting a load. With the prior arrangement described it must be obvious that the operating mechanism and the "cable 46 was under a severe strain and load during the periods when the scraper was being hauled to I transport a load, with the bucket raised. If the winch brake should accidentally release or if the cable 46 should break or snap, the beam 30 would automatically be freed and the means for retaining the bucket and load in a raised position would be ineffective, whereupon the bucket and load would drop to or toward the ground with the result that considerable damage might be done to the scraper or associated mechanisms.

An important aspect of the present invention is the provision of simple, efiicient and automatic means for positively retaining the bucket mechanism in a position insuring elevation of the bucket, without strain on the cables, winch, or other operating means. Although the invention is susceptible of being carried out in other forms and arrangements, it is found convenient, in connection with a bowl lift beam equipped, cable operated scraper to carry out the specific improvementsin the following manner:

fixed transverse pivot shaft 52. A lower portion or the latch hook 5| has pivotally secured thereto a clevis 63 to which is aflixed one end of a rod 54, the other end of said rod being slidable relative to a spaced guide plate 65 rigidly secured on the top of the members It. About the major portion of the rod 54 there is a compressed and confined coiled spring 56. The spring and rod arrangement is such that when the latch hook 5| is moved in either direction from dead center the spring exerts a force to quickly snap it to an extreme position on either side of dead center.

Normally the latch hook 5| assumes a position as shown in Figs. 3 and 5, with the latch hook in a relatively upright position having at the top end thereof a relatively wide opening or mouth 51. An intermediate under portion of the beam 30 has a hollow or open section between the lower side wall portions of which is extended a rigid, transverse, relatively massive latch pin 58.

When the bowl assembly of the scraper is in lowered position-that is, when the bottom plate 20 is projecting downwardly for digging purposes and the front gate 25 is raised, the bowl lift beam 30, as was previously explained, assumes an upwardly directed position as depicted in Fig. 3. If it is desired to raise the bowl structure for load confining and transporting purposes, the winch 44 is of course operated to reel in the cable 31 and to likewise reel in the cable 46. This action causes the beam 30 to swing on its pivot II in a counterclockwise direction relative to the drawings and the beam carried transverse latch pin 58 will ultimately contact the outer surface or the curved nose extremity 59 or the latch hook 5|, slightly rocking the latch hook in a counterclockwise direction and permitting the latch pin to move over the extremity of the hook nose 59 and into the mouth 51 until it engages an inner surface portion 60 of the latch hook substantially below the inner curved retaining surface SI of the latch hook nose. By this time the bowl structure will have been raised to its load carrying position and thereupon the winch is operated to provide slack in the cables with the result that the beam 30 will then snap upwardly slightly, firmly engaging th latch pin 58 in the curved recess M of the nose end of the latch hook, as shown in full lines in Fig. 5 and in broken lines in Fig. 3. This constitutes the latched Position of the beam 30 and with the beam thus engaged by the latch hook 5! it is unnecessary to have the cables taut or under tension and it is further unnecessary to have the winch or winch brake in operation, thus easing strain and tension on these various parts. The securement of the beam in lowered position by the latch hook insures retention of the scraper bucket in its elevated position and the scraper may be transported at a rapid rate or speed without any danger of having the load accidentally dropped.

When it is desired to release the engaged beam 30 and thereby lower the bucket structure, the winch is first operated to draw in on the cable 46 to pull the outer end of the beam 30 down slightly, causing the latch pin 58 to ride downwardly on the inner surface of the latch hook and away from the hooking end thereof. A relatively small movement of the beam in the direction indicated will cause, through the downward pressure exerted by the latch pin 58 against a side arm of the hook 5|, a pivotal movement of the hook in a counterclockwise direction relative to the drawings so as to swing the hook beyond dead center, whereupon the spring 56 will snap it to a position at an angle relative to its original position, as shown in Fig. 4, and in dotted lines in Fig. 5. After the latch hook snaps to the latter position the cables are slackened and as before mentioned, gravity and the weight of the structure and load will cause the frame members to swing on the pivot l9 and the beam 30 will commence moving in a clockwise direction (relative to the drawings) toward its raised or upwardly directed position. During the latter movement, the latch pin 58 rides upwardly alon the inner cam surface 62 of the latch hook, ultimately striking the eccentrically curved extremity thereof and thus rocking the latch hook 5! in a clockwise direction (relative to the drawings) with the result that upon sufficient movement of the beam 30 the latch hook will be rocked over its dead center position and the spring 56 will then snap it into its upright position, as in Fig. 3, whereupon continued upward movement of the beam 30 will cause th latch pin 58 to move entirely free of the latch hook 5|, thereby effectively automatically releasing the beam and permitting lowering and opening or the bucket structure.

From the above described construction and mode of operation of the improved scraper latch it will be evident that the latch automatically operates to effect securement and release of the bow. lift beam during normal operating movements of said beam in both directions. The engagement efiected by the latch is positive and there is no dependency on cables or other mechanism for holding the parts, including the scraper bucket, in retained position, thereby insuring safe operation and travel of a loaded scraper.

Although the improved scraper latch has been described in connection with a cable operated scraper it is obvious that the latch mechanism could be incorporated between relatively movable members in a scraper or like machine which is hydraulically or otherwise controlled and operated.

The improved scraper latch mechanism is incorporated in a scraper with little modification and with a minimum of parts. It is extremely simple in construction and operation, and is well adapted for the purposes set forth.

What is claimed as the invention is:

1. In a scraper having relatively movable ele-- ments operatively associated with a movable bucket assembly, a pair of complementary latch elements carried respectively by adjacent portions of a pair of said elements and automatically engageable and disengageable solely upon movements of the bucket assembly and relative movements of said elements, one of said latch elements comprising a hook having an entrance mouth with projections and cam surfaces thereadjacent, means rockingly mounting the end of the hook opposite the mouth on one of said ad- Jacent movable elements, and spring means to snap the hook to a rocked position on either side of dead center, the other of said latch elements consisting of a pin rigidly carried by the other of said adjacent movable elements and movable into the hook through the entrance mouth thereof and engageable with said cam surfaces to rock the hook in different directions.

2. In a scraper having hingedly connected front and rear wheeled frames, the rear frame including a bowl structure, an operating cable having an end extending to and operable from a pulling vehicle, means associated with said cable and responsive to a pull thereon, for raising said bowl structure to transporting position, latching mechanism including a pivotal latch element for locking said means in a position to hold the bowl in said transporting position after the cable has been pulled, means included in said latching mechanism and operable in response to a further pull on the same cable for causing pivotal movement of said pivotal latch element to releasing position, and means included in said latching mechanism operable in response to a lowering movement of the bowl structure after its release for causing pivotal movement of said pivotal latch element back to its set position.

HENRY C. FRENCH.

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