US1739175A - Power shovel - Google Patents

Description

1929. H. L.. MITCHELL ET AL Dec. l0,

POWER SHOVEL Filed April 16. 1926 2 Sheets-Sheet A TTORNEY` H. 1 MITCHELL ET A1. 1,739,175

POWER sHovEL Dec. l0, 1929.

2 Sheets-Sheet 2 Filed April 16. 1926 @ma I l TTORNEYJ` Patente-d Dec. 10, 1929` HOLGER L. ANI) ROLE` LJ'UNGKULL, OF MILWAUKEE, WISCONSIN, ASSIGN- -ORS T0 EVARNISCHFEGR CORPORATION,

RATION OF WISCONSIN Application filed April 16,

This invention relates to improvements in power shovels, and more particularly to those of the internal combustion engine operated type wherein the shipper shaft is chain driven from what is termed the digging shaft77 mounted near the forward end of the revolvin platform or turntable of the machine.

iiiiculty has been encountered in raising and lowering the boom on these machines, due to the fact that it interferes with the tene sion ofthe driving chain previously mentioned, the pivotal axisof the boom being below and in advance of the axis of the digging shaft so that the distance between/'the v latter and the shipper shaft varies with adjustment of the boom. r

One object of the invention, therefore, is -to provide compensating means in conjunction with the boom and chain for automatically regulating the tension of the'latter throughout various adjustments of the boom.

Another object resideslin the provision of improved brace rods for the boom including the provision of means for absorbing the shocks incident to the side swipes or thrusts encountered by the dipper stick. d

. Other objects and advantages will. become apparent from the following description taken in connection with the accompanying drawings wherein one form of the invention is illustrated.

Figure 1 is a slide elevational view of the front and of a power shovel, showing the improved tension means applied thereto; v

Fig. 2 is an enlarged plan View of Fig. 1, some of the parts being removed;

Fig. `3 is a side elevation of Fig. 2;

Fig. 4 is an enlarged section on` line 4 4 of Fig. 1;

Fig. 5 is an enlarged section on line 5-5 of Fig. 3;

Fig. 6 is a section on line 6-6 of Fig. 5; and

Fig. 7 is a bottom plan vieW'of one of the parts in Fig. 5. n

Referring more particularly to the drawings and first to Figs. 1, 2 and 3 thereof, a clipper stick 1 provided at its outer Vend with av shovel 2 of any suitable construction 1s mounted upon a boom 3, the latter being pivotally attached to the forward end of the re-f OF MILWAUKEE, WISCONSIN, A CORPO- POW'ER. SHIOVEILV 1926. Serial No. 102,397.

volving platform or turntable 22. The socalled crowding vaction or back and forth movement is imparted to the dipper stick by mechanism of well-known construction which comprises,V in general, the sprocket wheel 5 mounted on the digging shaft 4, the sprocket wheel 6 fixed upon the shipper shaft 7 and connected to sprocket wheel 5 by means of a sprocket chain 8, and suitable pinions (not shown) which are fixed on shipper shaft 7 and engage racks 9 on the gnderside of the dipper stick.

As previously explained and from the arrangement of parts just described, it will be apparent that uponpivotal adjustment of the boom 3 the distance between the shipper shaft and the digging shaft will be varied. Thus, it will be apparentthat the drive or sprocket chain if passed directly between sprocket wheels 5 and 6 would be extremely taut when the boom was in its lowermost position of adjustment, while any adjustment from such point upwardly would result in slackin the chain. To provide against this diiculty the present invention, as above pointed out, contemplates the provision of means vfor automatically regulating or controlling the tension of the cha-in upon adjustment of the boom, this means being so constructed and arranged as to maintain the chain tension at substantially a constant value. To this end, the invention contemplates, in the form thereof illustrated in the drawings, the provision of triangularlyshaped members 10 and 11 arranged on either side of boom 3 and pivotally connectedthereto by means of a pin 12 extending through the -f boom and the forward ends of these members.

A sprocket wheel 13\is arranged betweenmembers 10 and 11 and is held in operative or assembled relation with lrespect thereto b means of a pin'14 passingloosely throng this sprocket wheel and having its ends `mounted in members 10 and 11 and held base 19 and upwardly extending spaced arms 2() and 21, is secured to the revolvable frame or platform 22'of the machine by means of bolts 23, arms 2O and 21 embracing members 10 and 11 and being connected thereto .by means of bolts 24 and 25 or the like provided `with heads 26 and 27 arranged for sliding movement in slots'or grooves 28 formed in members 10 and 11.

The operation of the improved tensioning or equalizing device is as follows: Upon elevation of boom 3, for example, through an angle of about 30 .degrees from the full-line p0- sition `thereof shown in Fig. 3, the heads 26 and 27 vof bolts 24 and 25, respectively, will coact with the grooves 28 in me bers 10 and 11 to cause pivotal movement of the latter in a counter-clockwise direction with respect t the boom about pin 12 'as a center, vso that sprocket wheels 13 and 16 and chain 8 trained thereabout assume the dotted line position shown, the contour and position of the slots or grooves 28 bein such as to cause just the right amount of plvotal movement of meinbers 10 and 11 with respect-'to the boom to take up on the chain an amount equal to the play or looseness which would otherwise result upon this elevation or adj ustment of the boom due to the fact that the arcuate path of shipper shaft 7 about the pivot pin 3a connecting the lower end of the boom to frame 22 is eccentric to and below the axis of rotation of digging shaft- 4.' The contour and position of the grooves or slots 28 is such that upon lowering of the boom bolt heads 264 and y27,

which are relatively fixed, act to cause pivotal movement ofmembers 1() and 11 in a clockwise direction with respect to boom 3 about pin 12 as a center, whereby more of the crowdling chain is made available to compensate for the increase in the distance between the respective and digging shaft 4.

For the purpose of providing for wear Ain chain 8, members and 11 may beprovided proved means have beenl provided to autoi matically take upfon the crowding chain 8 upon raising of the boom insuch manner that the tensionin the chain is substantially constant, the improved tensioning or equalizing means acting in the reverse manner upon 'lowering of the boom.

The boom 3 is provided at each side thereof with brace rods 32 connected to the boom at their up er ends by means of a bolt 33 and threade at their lowerJends to receive nuts 34, rods 32 being provided with the usual axes of rotation `of shipper shaft 7 turnbuckles, as shown. A hollo'w cylindriaal member 35 is fitted over the lower end of each rod and provided with spaced apertured lugs 36 which receive a bolt 37 whereby member 35 is pivotally connected to the front end of frame 22, bolt 37 passing through a suitable lug 38 withwhich the frame may be provided.` A spring 39 is arranged upon each rod 32 and is compressed between nut 34 and a cap 40 loosely fitting the rod and closing the open end of member 35. The cap 40 is provided with inwardly extending, diametrically arranged fianges 41 spaced laterally from the cap body and adapted to lit between similarly .outwardly extending ianges 42 with which member 35 is provided at its open end.v

the arrangement being such that when cap 40 v is fitted upon member 35 and given a quarter turn, the cap will be locked in posit-ion, as more clearly shown in Fig.- 5. y Member 35 and cap 40 may be provided with apertured lugs 43 and 44, respectively, the lugs beine' arranged to register when the cap is in locking position and'receiving a bolt 45 for holding the cap in this position. By means of the construction just described, springs 39 provide a cushion to relieve the boom, dipper stick, the shipper shaft and the various other parts/from the sudden shock which would otherwise occur due to side swiping with the dipper, or laccidental engagement with an obstruction, lthe springs being of equal tension vand acting normally to hold the'boomin alignment'with the longit-udinal center line of the revolving platform.

The brace rods 32 and the cushion means orl springs 39 associated therewith have been shown applied to the boom of a power shovel, but of course they may be used with equal effect for bracing the booms or like members of hoisting mechanism of other types.

While a definite embodiment of the inven-j tion has been shown and described, it will be understood, of course, that various changes may be made in the size, shape and arrangement f the parts without departing from the spirit of the invention or the scope of the claims. v

The invention claimed is:

1. In a machineof the characterl described, the combination with a supporting frame, a driving shaft rotatably mounted on said frame, a boom connected to said frame for pivot-al movement about an axis eccentric to the axis of rotation of said shafta shaft carried by said boom, and a flexible driving element connectin said-shafts and traveling in a plane at rig t angles `to the axes of the` shafts, of means associated .with said element and in its plane of travel and coactingrtherewith for automatically compensatii'igl for changes in the relative positions of' said shafts upon said movement -of the boom whereby the tension in said element is maintained substantially constant through the en# ico..

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izov I tire range of movement of the boom with -respect to the frame. 'y

2. In a machine of the character described, the combination with a supporting frame, a

driving shaft rotatably mounted on said frame, a boom connected to said frame for pivotal movement about an axis eccentric to the axis of rotation of said shaft, a shaft carried by said boom, and a flexible driving element connecting said shafts, of means associated withsaid element and coacting therewith to compensate for changes in the relative positions of said shafts upon said move ment of the boom whereby the tension 1ny said element is maintained substantially constant throughout the range of operation of the boom, said means includin a member pivotally connected to said boon and a second member relatively fixed wit respect to said frame` one of said members being pro- A vided with'a groove, the'other of said members being adapted and arranged `to traverse said groove whereby said first' member. is

caused to change its angular relation with re-v engaging said element, a member supporting said means for pivotal movement about an axis relatively fixed with respect to sai d boom, and a second member fixed relatively with respect to said frame and coacting with said first-named member to cause said movement of said means upon pivotal movement of said boom whereby said means acts tomaintain the tension of said element substantially constant throughout the range of movement of the boom.

4. Ina machine of the character described, the combination with a supporting frame, a driving shaft rotatably mounted onsaid frame, a boom connected to said frame for pivotal movement about an axis eccentric to the axis of rotation 'of said shaft, a shaft carried by said boom, and an endless drive chain connecting said shafts, ofa pair of members arranged on opposite sides of said boom and connected to the latter for pivotal `movement with respect thereto about an axis relatively fixed with respect to the same, said members being provided with grooves, a pair of sprocket wheels arranged between said members and rotatably supported thereby, said wheels engaging the respective runs of said chain, and elements fixed relatively *ith re- Y spect to said frame and adapted and arranged to traverse said grooves whereby said members are caused to change their angular rela.-

tion with respect to said boom in such wise as to cause said sprocket wheels tro maintain the tension of said chain substantially constant for all positions ofthe boom throughout the range of movement thereof.

5. In a power shovel, the combination with a supporting frame, a boom pivotally connected to said frame, a shaft carried by said boom, a driving shaft rotatably mounted on said frame, and an endless chain connecting said shafts, chain take-up means comprising a member pivotally connected to said boom, and a second member fixed relatively with respect to said frame and engaging said first member to cause pivotal movement thereof with vrespect to said boom upon angular adjustment of thelatter with respect to said frame. said first member engaging said chain.

6. The combination with the boom and crowding chain of a power shovel, of means associatedtherewith for automatically regulating the tension of said chain upon adjustment of the boom, said means including a member pivoted to the boom and engaging said chain, and means for guiding said member in its movement incident to adjustment of the boom. i f

7. The combination with .the boom and crowding chain of a power shovel, of means associated therewith for automatically regulating/the tension of said chain upon adjustment f the boom, said `means including a vmember pivoted to the boom and engaging Said chain, and means for supporting and guiding the free end of said member to confine and control the movements thereof occasioned by adjustment of the boom. Y

8. The combination with the boom and crowding chain of a power shovel, of means associated therewith for automatically regulating the tension of said chain upon adjustment of the boom, said means including a member pivoted to the boom and engaging said chain. j

9. lhe combination with the boom and crowding` chain, of a power shovel, of means associated therewith for automatically reguf lating the tension of said chain upon adjustment of the boom, said means including a member pivoted to the boom andengaging downwardly upon both runs of said chain.

l0. rlhe combination with the boom and crowding chain of a power shovel, of means associated therewith for automatically regulating the tension of said chain upon adjustment of the boom, said means including arms pivoted to opposite sides of said boom and extending rearwardly therefrom on both sides of said chain, a plurality of pins extending between said arms, and sprocket wheels mounted on said pins and engaging both runs of said chain.

11. The combination with the boom and crowding chain of a power shovel, of means associated therewith for automatically regujlating the tension of said chain upon adjustment of the boom, saidmeans including arms pivoted to opposite sides of said boom, a plurality of pins extending between said arms, sprocket .wheels mounted on said pins and engaging both runs of said chain, and means engaging one of said arms for controlling the movements of said sprocket wheels upon adjustment of the boom.

12. The combination with the boom and crowding chain of a power shovel, of means associated therewith for automatically regudescribed, the combination of a supporting frame, a boom pivotally mounted on/the frame, a driving element on the frame, a driven element on vthe boom, the arrangement being such that the distance between the elements is varied by pivotal movement of the boom, a fiexible connector associated with the driving element and the driven element, an equalizing device adapted for movement with respect to the boom and the framefor varying the path of travel of the flexible connector and means for positively actuating said equalizing device to com# pensate for the varying distance between the driving and driven elements upon pivotal movement of the boo-m so as to maintain the length of the path of travel of the flexible connector constant.

14. In an excavating machine of the class described, the combination ,of a supporting frame, a boom, a pivot for securing one end ofthe boom to the frame, a driving shaft and a sprocket wheel on the frame, a driven shaft and sprocket wheel onthe boom, the arrangement being such that the distance between shafts is varied by pivotal movement of the boom, a sprocket chain connecting the sprocket wheel on the boom to the sprocket wheel on the frame, the path of travel of said chain being in a single plane and means in said plane actuated by the boom for prethe path of travel of said boom about its pivot` and means actuated by said boom for preventing slack occurring in said flexible connector when the distance between the shafts is variedby movement of the boom about its pivot.

16. In an excavating machine of the class described having a frame and a boom pivoted thereto, two shafts adapted to rotate about parallel axes, one shaft beingimounted on the frame andthe other on the boom, a flexible connector for conveying torque from one shaft to the other and adapted to travel in such a way that it remains in a given plane, the arrangement being such that the distance between the axes of the shafts is varied by pivotal movement of the boom, equalizing means for maintaining the length of the path of travel of'a point on the connector constant and means for automatically and positively actuating. said ,equalizing means to compensate for the variations in the distance between the'axes of the shafts caused by pivotal movement of the boom over its entire range of movement.

17. In an excavating machine of the class described having a frame and a boom pivoted thereto,l two shafts adapted to rotate about parallel axes, one shaft bein mounted on the frame and the other on the oom, a sprocket chain for conveying torque from a sprocket wheel on one shaft to a sprocket wheel on the other, the arrangement being suchthat the distance between the axes of the shafts is varied by pivotal movement of the boom and equalizing means for preventing slack in the chain when the boom is moved about its pivy ot, said equalizing means consisting of a carrier actuated by the boom, means for constrainingthe movement of the carrier to a definitepredeterminedpathJJ and guides carried by the carrier for engaging both runs "of the chain.

` In witness whereof we hereto aiiix our sig natures.

HGLGER L. MITCHELL. ROLF LJUNGKULL.

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venting slack in the chain when the boom is rotated about its pivot.

15. In an excavatingmachine of the classl described, a frame, a boom'pivoted to the frame, a shaft on ,the boom, a shaft on the frame, a continuous flexible connector associated with said shafts for conveying torque4 from vone to the other, the path of travel of' said iiexible connector being in the plane of

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