US2398860A - Material handling apparatus - Google Patents

Description

April 23, 1946. w. RUDDOCK 2,398,860

MATERIAL HANDLING APPARATUS Filed Jan. 20, 1945 30 35 3, 45 46 INVENTOR.

5a Win/411419000006, 34 BY 40 ATTORNEY.

'hardnessorthelike.

Patented Apr. '23, 1 946 umrso STAT H MATERIALHHANDLING APPARATUS William Ruddock, sedan Pasadena, calm, as-

signer of one-half to Angeles, Calif.

Marlon P. McCaflrey,-Los

ApplicationJanpary 20, 1943, Serial No. 972,978 10 Claims. (01. 2145-140) This invention relates to material handling apparatus; More particularly it relates to'shock absorbing means for use in connection with the movable bucket -or material engaging element c mmonly-used on such apparatus. This appli-.

cation relates to an improvement of apparatus such as disclosed in an application entitledM terial' handling"apparatus,-" filed November 10, 1941-, in the name of William Ruddo'ck, and. bearing Serial No. 418,557, now Patent No. 2,362,406,

granted November 7, 1944. r

Such apparatus includes a bucket or the like vide a novel 'form of shock absorber for material attached to an arm which is adapted to bezraised.

lowered or otherwise moved so as to load or unload the bucket, or to transport the loaded" bucket. v a The capacity; of machines of this nature is to some extent restricted by the width of the bucket;

Thus, to provide suitable capacity as well as to provide machines for special purposes, for example wherein the bucket acts as a scraper, it is common to utilize a relatively wide bucket or material engaging element. This necessitates the force to the bucket at two points which are widely spaced transversely of the bucket. 1 a

A cable or cables are commonly used to transmit force to such buckets from a drum mechanism operated by a source of power on the apparatus, althoughchfiins might be used, or an It is another object oithis invention to provide means providing resilience in the connection bea tween .the. cable element and ing element.

It is another obje'ctof. this invention to prohandling equipment.

It is still another object of this i ventionto provide improved means for equalizing the-forces 7 in the cable elements of such apparatus.

It is still a'iurther object .ofv this. invention to provide shock absorbing means. and equalizing means which cooperate and form a simple, compact'ar-rangement. I

This invention possesses many other advantages, a'n'd has other objects which may be made more easily apparent from a considerationpf one embodiment of the invention. For this purpose there is shown a form inthe drawing accomprovision of means which will'apply the lifting element composed partly of rods and canes or chains.

When a pair of such cable elements are used, as for lifting a wide bucket, it is preferable to provide equalizing means which will insure equal stresses in the cable elements. This not'only avoids the difficulty of initially adjusting theparts to obtain equal tension in the cables, but'.

also compensates for variations due to operating conditions, such as unequal spooling of the cables on thewinding drum, unequal distribution of load in the bucket, etc. 1

Further, in such apparatus, whether using a pair of cable elements or not,.the'cable element as well as the entire machine is subject to severe shock and stress due tosudden stoppage of' the loadedv bucket ,as by application of thebrakes which control the drum mechanism. Severe shocks .to the machine may also resultiromthe,

bucket encounteringhard Or fixedobjectsinfthe adapted to pick up and 'carry'a load of material .suchijas earth,'gra'vel, crushed rock. or the.like.;- It will be plainthat swingingof the-arm, l2 about U material being handled, or in'loading mixtures of It is an objectfof the present vide. improved I means for absorbing such' shocks. I

invention topro H materials of different 'characteristics'fpf weight,

panying and forming part-of the present'specifi cation. This form will now be described in detail.

illustrating the general principles of the invention; but it is to be understood that thisdetalled' description is not to be take'njin'a limiting sense,

since the-scope of the invention is'best defined by theappended claims. a

Referring to the drawing:

Figure 1 is .a' side elevation of one type of material handling apparatus'with which the present invention may be. employed Figure 2*is a detail 'planof the end 'of the hoisting arm; Figure 3 is' a longitudinal section absorbing mechanism, on an enlarged scale;

; Figure 4' is a view looking upward from the bottomof Figure 3; and, j

Figure 5jis a fragmentary elevation-of a modified form of theinvention.

Referring to the drawing, there-is shown in Figure 1. a tractor shovel, which. may be of that type disclosed in my PatentNo. 2,260,539; issued October 28, 1941, "and. entitled Tractor shovel." This machine comprises a frame l0, arranged for movement over-the ground, as by being mounted on Caterpillar tracks ll, -A hoisting arm or boom I2 is pivotally supported on the frame H) as at 14 and carries a bucket or scoop; l3 at one end.

the pivot l4 serves to raise and lower bucket-l3.-

- I Inorder to control such swinging ,movement acable element 15 which cooperates with a'wln'd ing'drum mechanism-26 isprovided. TIhis mach an'ism may. include. a friction clutchor the like Y the material engag bucket and outer a of. the shock As clearly shown in Figure2, the bucket I3 and the arm structure I2 are relatively wid and in order toproperly support them, the supporting force exerted by the cable element I5 should be applied at widely spaced points as I6 and II. To do thisconveniently, the cable element I5 may have a pair of reaches I8 and I9 which are respectively operatively connected to the bucket I3 at the points I6 and II. By applying'simultaneously acting equal forces on the cables I8 and I9, the bucket I3 is lifted or controlled without distortion and without developing twisting or weaving stresses in the arm I2, frame I0, or other parts of th machine.

However, due to various factors, such as the difllculty of initially adjusting separate cables to insure equal tension in both cables, unequal distribution of the load in the bucket I3, Wear of the working parts, etc., it is desirable to provide some means for automatically ensuring that the tension in the cables I8 and I9 is equal at all times and under all load conditions. Accordingly, the cable reaches I8 and I9 are united by a lateral section 23, 2! to form a bridle for supporting the bucket and arm assembly, and sheave wheels 22 and 23 over which the cable I5 passes are'provided to form the points of attachment I5 and I1. With this arrangement, if the tension in one reach of the cable, for example I8, exceeds.

that in-the other reach I9, a slight movement of the cable toward the higher tensioned reach will 1 occur about the heaves 22 and 23, shifting the lateral portion 20, 2| of the cable slightly to the right (Fig. 2).

To accommodate movement of the bucket I3 about the pivot 21, with respect to arm I2, the sheaves 22 and 23 are attached to the bucket so as to be swingable about axes parallel to the axis oi the pivot 21. Thus, the sheaves 22 and 23 are rotatably supported on pin 5i and 52, which in turn are carried in U-shaped members 53 and 54. The members 53 and 55 respectively are mounted on pins 55 and 55 secured to the back plate 32 of the bucket by ears 51. Members 53 and 54 are joined by parallel bars form a bridge structure or frame 55.

It is also desirable to prevent shock or impact loads being imparted to the cable I5 and other 58 and 59 to parts of the mechanism by the bucket I3. Such shocks may be very severe upon the udden application of the brake means on the winding drum mechanism to check the descent of the loaded bucket, or they may result from one corner of the bucket striking hard material, such as boulder, during digging operations. Accordingly, it is desirable to provide means for introducing resilience-into the cable I5.

In the instant case, a shock absorbing means is provided wherein the resilience is provided by a compression spring so arranged that the lateral portions 20, 2I of the cable I5 have a toggle ac' tion with respectto the spring and only a small part of the tension in the cable acts on the spring.

Further, to avoid over stressing one reach I8 or I9 of the cable I5 under an impact load before the equ izin means has a chance to act, it is desirable to place the shock absorbing means symmetrically in the cable system. Accordingly, the shock absorbing means, indicated by 25, is mounted on the bridge 60 intermediate the sheaves 22 and 23.

As shown in Figure ,3, the shock absorbing means 25 includes a hollow cylindrical member 30 open at one end and provided with a base 3i at its opposite end, the base 3| being secured as by welding to the bars 58 and 59 of the bridge. 60. Slidable over the cylinder 30 is a tubular member 33, and confined between the base 3| and the head 34, is a compression spring 35, urging the member 33 outwardly ofthe cylinder. An adjustable stop 36 may be provided to maintain the parts in assembled relationship until the cable element I5 is installed.

Secured to the head 34 is a saddle member 39, having an arcuate groove 30 for accommodating the laterally extending portions 20, 2I of the cable I5.

Since the sheaves 22 and 23 and shock absorber 25 are all mounted on the bridge structure 60, they are maintained against relative movement, but can move as a. unit with respect to the bucket I3. Thus, no misalignment or cramping of the parts can occur as the bucket I3 moves with respect to arm I2, and the laterally extending portions 20, 2I of the cable element are maintained in the same plane with respect to the sheaves and shock absorber for all positions of the bucket I3.

The operation of the mechanism may now be described. As previously explained, any inequality in the tension of the reaches I8 and I9 of the cable i5 is equalized by a slight shifting of the lateral portion 20, 2| of the cable toward the reach that is most heavily loaded, this movement causing slight rotation of the sheaves 22 and 23 as well as causing the portions 20, 2I to slipon the saddle 39. Otherwise, the cable I5 does not move with respect to the frame 60, that is, it has no translatory movement with respect thereto.

From an inspection of Figure 2, and considering the ends of the cable reaches I8 and I9 as fixed, it will be plain that the force of the spring 35 tends to increase the length of the cable in the lateral portions 29, 2i and reducing the effectivelengths of the reaches I8, I9. Thus, any impact load acting either on the bucket I3 or on the cable I5 tending to increase this effective length is yieldingly opposed by the spring 35. Shocks to the mechanism are thereby avoided.

The lateral portions 23 and 2i of the cable by forming less than a straight angle with each other, have an action on the spring analogous to that of ,a toggle. That is,. a substantial change in this angle, corresponding toa considerable change in the height of the spring 35, will result from. only a slight change in the effective lengths of the cable reaches I8, I9. Consequently, a comparatively light spring at 35 will suffice to hold relatively large tension forces in the cable I5.

Under certain conditions of operation, it may be desirable to equalize the tension in the cable element and then secure the cable element in and utilize only the is secured to the saddle 3 9. Abolt GGQ is threaded through the piece and carries a plate I! adapted to engage the cable. It will be apparent that appropriate rotation of the bolt 46 will serve to force the plate 41 against the cable and clamp it against movement relative to the saddle.

the saddle 39, should the cable become slack for any reason. i

A modified form of shock absorber is shown in Figure 5. Therein, a sheave 50 is rotatably 'mounted on the end of the tubular member 33,

This means also acts, even when not clamped, to prevent the cablejumpingout of spring maintaining the cable bowed outof alignment for absorbing impact loads acting in the cable.

5, In material handling apparatus, a material engaging element andarm assembly, mounted "for movement to raise and lower said element,

means for controlling said movement including a cable element, a bridge structure movably mounted 'on said assembly and extendingtransversely and carries the lateral portions .20 and H of the cable, after the manner ofthe saddle-39. -In this arrangement, the frictional drag of the cable across the saddle, which-in some cases might be considerable, is eliminated and more perfect as 4 well as more immediate equalization of the forces in the two cable reaches 18 and I9, can be achieved.

I claim: I i 1. In -a material handling apparatus, a material engaging element and arm assembly mounted-for movement to raise and lower said element, a pair of transversely spaced sheaves mounted on said assembly, force. exerting mechanism for controlling said movement and including a cable element operatively connected to the assembly by means of said sheaves, and having a portion extending between the sheaves, and mechanism carried by said assembly between said sheaves including a compression spring acting .on that portion or the cable between the sheaves for absorbingimpact loads on the cable, the force of the spring opposing the force in the cable and acting transversely thereto. r

2. In material handling apparatus, a material engaging element, an arm on which said element is mounted for movement with respect to said arm, said arm being mounted for movement to raise and lower said element, meansfor controlling said movement comprising a cable element, a

bridge structure movably mounted on said material engaging element and extending transversely thereof, a pair of sheaves mountedon said structure at spaced points, said cable element passing J about and between' said sheaves, whereby-the forces acting on the structure at said points'are equalized, a member acting on the cable between said sheaves permitting resilient movement/bethe forces acting on said structure at said points tween the cable. and said structure, said member bein so positioned with respect to the cable that tension in the cable is opposed by said member in a direction transverse to the cable.

'3. In load handling apparatus including a cable element, a frame member, spaced meansat a fixed distance apart connecting said cable with said frame, a compression spring mounted on said frame between said spaced means, and engaging said cable element, said cable'element being adapted to be connected at one-end, to'force thereof, means movably securingsaid cable to said structure at s an of spacedpoints, said cable passing between said points whereby the forces acting on said structure at said poin'ts'are equalized, andmeans carried by said structure intermediate said points, exerting a resilient force on the cable acting transversely thereof andopposing'zthe force .in the cable, for maintainin f the cable bowed out of alignment between said points. g

6.. In material handling apparatus, a material engaging element and arm assembly, mounted for movement to raise and lower said element; means for controlling said movement, including a'cable element, a bridge structure movablymounted on said material engaging element and extending transversely thereof mean movably securing said cable to said structureat a pair of spaced points,

said cable passing betweensaid points whereby are egualized, and means carriedby said structure intermediate said points, exerting aresilient force on the cable acting transversely thereof and opposing the force in the cable,- for maintaining the cable bowed out of alignment betweenjsaid points.

7. 'Infmaterial handling apparatus, a material I engaging element and arm assembly, mounted for movement to raise and lower said element; means for controlling saidmovement, including a cable element operatively connected to said assembly at a pair of spaced ,points, said cable passing be-,

tween said points whereby the forces acting on I said assembly at said points are equalized, a pair' of elements in telescopic. relation interposed be tween'said assembly and the cable intermediate I said, points, and means resiliently urging said m'embers apart whereby'a force is exerted on the cable transversely thereof and opposing the force. in the cable for maintaining the cable bowedfout' of alignment between said p ints.

8. In material handling apparatus, a material engaging element and arm assembly mounted for movement to raise and-lower said element, a pair exerting mechanism and at the other end to a: means for maintaining the cable against substantial translatory movement with respect to the irame-during'transfer of force between the cable and the.frame,fsaid spring serving to vary the extent to which the cable is bowed out of alignment in accordance with the force'acting'on of transversely spaced sheaves mounted 0n said element, force exerting mechanism for controlling said movement and including a cable element connected to the material engaging element by;

means of said sheaves, and having a portion extending between-the sheaves, and mechanism carried by said material engagin element between said sheaves, acting on that portion of the. cable between the sheaves for absorbing impact loads on the cable, said mechanism exerting a force opposing the force in the cable and acting trans- 'versely thereto;

.9. In material handling, apparatus, a material I engaging element-and arm assembly mounted for movement to raise and lower said element, means for controlling said movement comprising a cable operatively connected to said assembly ata pair of spaced points, said cable passing between said points whereby the forces'actingon saidassemelement operatively connected to said assembly,, a compression spring for exerting a, force transversely to tension in the cable, the force 'of sa1d 4 bly. at said points are equalized. and mechanism carried by said assembly between said points, in-

cluding a compression spring acting on that portion of the cable between the points for absorbing impact loads on the cable, the force of the spring opposing the force in the cable and acting transversely thereto.

10. In material handling apparatus, a material engaging element and arm assembly mounted for movement to raise and lower said element, means for controlling said movement comprising a cable .mechanism exerting a force opposing the force in the cable and acting transversely thereto.

RUDDOCK.

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