US2259659A - Trenching machine - Google Patents

Description

Oct. 21, 1941. v. s. PENOTE ET AL TRENCHING MACHINE Oct. 21, 1941. v. s PENOTE ET AL 2,259,659 TRENCHING MACHINE Filed Oct. 1:5, 19:59 4 Sheets-Sheet 2 Mmx Oct. 21, 1941. v. s. PENOTE IQET'AL TRENCHING MACHINE Filed OQt. 13, 1939 4 Sheets-Sheet 3 NNN MNN 3w RN mww RN Oct. 21, 1941.

V. S. PENQTE ET AL TRENCHING: MACHINE Filed Oct. 13, 1959 4 Sheets-Sheet 4 1 H mm $5M 3.3m PA W7 Z N4. w 4

i atented Oct. 21, 1941 2,259,659 I TRENCHING MACHINE Vincent S. Penote, Cleveland, and Albert R."

Askue, Mentor, Ohio, assignors to The Cleveland Trencher Company, Cleveland, Ohio, a

corporation of Ohio Application October 13, 1939, serial No. 299,306 19 Claims. (01. 37-97) This invention relates to an excavating or trench digging machine, and more particularly to an improved trench digging machine; which will be so constructed and arranged that the machine may be operated with a minimum number of controls, and in an economical manner. This, therefore, is one of the objects of the present invention.

A further object of the present invention is to provide a trench digging machine of the rotary digging wheel type with an improved digging wheel supporting and driving mechanism, which will simplify the construction and operation of the machine.

Another object of this invention is to provide a trenching machine, with an improved driving mechanism for supplying and controlling the power applied to the machine progressing mechanism, the digging unit and the conveyor which ejects the dug material from the machine.

A further object of this invention is the provision of a trench digging machine having an improved power transmission mechanism which mechanism will be compact, rugged and so arranged as to be conveniently operated at various digging and running speeds.

Another object of this invention is to provide an improved trenching machine which will be of exceptionally light weight and especially adapted for the digging of comparatively narrow trenches under restricted space conditions, and which machine will be economical to construct and operate.

Other objects and features of this invention will become more apparent from the following description, reference being had to the accompanying drawings in which we have shown a preferred embodiment of the invention. The essential features of the invention will be summarized in the claims.

In the drawings, Fig. l is a side elevation of a trench digging machine constructed in accord with the present invention; Fig. 2 is a rear elevation of the machine illustrated in Fig. 1; Fig. 3 is a fragmentary transverse sectional view of the trench digging machine, the plane of the section being indicated by the lines 3-3 on Fig. 1; Fig. 4 is a sectional detail of a portion of the digging wheel supporting mechanism, the plane of the section being indicated by the lines 4-4 on Fig, l Fig. 5 is a substantially horizontal sectional view illustrating the propelling mechanism, the plane of the section being indicated by the line 5-5 on Fig. 1; Fig. 6 is a side elevation of the gear box Ill for the propelling mechanism, and Fig. '7 is a plan view or the gear box shown in Fig. 6.

Referring now to the drawings, and particularly to Fig. 1, the trench digging machine with which the present invention is concerned, comprises in general a main frame I!) supported by a pair of transverse frame members II, the ends of which are secured to tractor belt supports l2. The supports I2 are each provided with a wheel [4 and a sprocket'wheel I5; about which an endless tractor belt chain i6 is looped in the usual manner. 7 Suitable rollers or wheels I8 are mounted on the supports l2 and coact with the belt intermediate the wheels and sprocket to distribute the load of the machine along the entire lower stretch of the tractor belt.-

- Mounted inthe extreme forward end of the machine frame 10 and disposed forwardly of the tractor belts is a motor such as, for instance, a gasoline engine ll, of the automotive type. At the rearward end of the machine there is an inclined guideway 20. As shown in the drawings,

the lower end of this guideway is mounted on the rearward end of the frame l0, and extends upwardly and forwardly to a point which, as shown, is substantially above the center of the tractor belts. Suitable bracing, such as the struts 2| and 22 are provided to insure rigidity of the structure. This guideway supports, as will be hereinafter more fully described, a rearwardly extending supplemental frame 25 which carries the digging unit 26.

The digging unit supporting frame 25 comprises a pair of substantially longitudinally extending, spaced frame members which are secured together at their opposite ends, as for instance, by cross-frame members 21. At its forward end the supplemental frame 25 is pivotally connected, by suitable pivot pins 30, to a carriage 3|, which is slidably mounted for movement in the guideways 20, which as shown, comprise a pair of inwardly facing channels 32. The carriage 3| is provided adjacent its upper and lower ends with rollers 33, arranged to engage trackways 34 secured to the flanges of the channels 32, as shown in Fig. 3. Preferably, the carriage comprises two pairs of channel members 35 secured together at their upper and lower ends by cross-members 36, and provided with front and rear plates 31, thus forming an enclosed box-like structure.

,The supplemental frame, together with the digging unit carried thereby is raised and lowered in the guideway 20 to regulate the depth of cut to be made'by the digging unit as well as to raise such unit to facilitate the transportation of the machine from place to place. As illustrated in Fig. 1 of the drawings, the supplemental frame 25 is pivotally connected to the lower end of the carriage 3|.

The rearward end of the digging unit supporting frame is supported by a pair of cables 42. As shown in Fig.- 1, a shaft 45 is mounted at the upper end of the carriage and has, at its opposite ends, sheaves 4| which extend outwardly beyond the guideway channels 32. The cables 42 each have one end thereof secured to a respective guideway channel 32, as indicated at 43, and then pass upwardly around respective sheaves 4| to respective sheaves 44, which are pivotally attachedat 45 to bracket formations 46 at the rearward end of the supplemental frame 25, and on opposite ides thereof. From the sheaves 44 each cable 42 passes forwardly as at 41 and is secured to the upper portion of the carriage to which the inner end of the digging wheel frame is pivoted.

The raising and lowering of the supplemental frame 25, together with the digging unit or wheel 26, is accomplished by a single operating means. As shown in Fig. 4, a hydraulic cylinder 50 is secured to the frame l and extends upward between the guideway channels 32., Suitable conduits lead from this cylinder to a hydraulic pump 53 which is driven by the motor I! in any suitable manner. A valve mechanism controlled by a lever 52 is interposed in the conduit 5| and controls the flow of fluid to and from the cylinder 55.

The cylinder 50 is provided with a piston (not shown) but the plunger 54 of which extends upwardly through the cylinder and is secured as indicated at 55 to the upper end of the carriage 3 I.

The operation of the hydraulic lift mechanism thus will move the supplemental frame and digging wheel 26 from the full line position shown in Fig. 1 to the dotted line position therein indicated, or vice versa. It is to be noted that the rearmost end 25a. of the digging wheel supporting frame 25, during the lowering movement will move at a greater rate of speed than the forward or pivot end, thus when the wheel reaches substantially the position shown in dotted lines, the frame 25 will be substantially horizontal. Indeed, the arrangement is such that for all practical purposes the wheel will be supported level, the frame 25 will be substantially horizontal during most digging depths, to facilitate the use of a belt conveyor carried by the frame to eject the material removed from the trench by the wheel. This present construction is a decided advantage over constructions used in the past, which have used operating mechanism requiring numerous controls. When the digging imit is raised to the position illustrated in full lines, in Fig. l, the inclination of the guideways cause the digging unit to be moved bodily forwardly (to the left in Fig. l) thus moving the center of gravity also forwardly, at the same time the reeving of the cables 42 raises the rear or right hand end of the digging unit faster than the pivoted end thereof, thus swinging the digging unit upwardly about its pivots 3B and reducing the lift required to raise the digging unit to the full line position. At the same time, this swinging movement of the digging unit moves the balance of the machine still further forward, thereby facilitating the transportation of the machine from one place to another under its own motive power and at a comparatively high rate of speed.

The simplification of the positioning mechanism for the digging unit reduces not only the number of controls to a minimum, as for instance, to one control lever as shown in the drawings, but also reduces the number of parts required, thus reducing the weight and size of the machine to a minimum thereby facilitating the use of the machine in close quarters, and as, for instance, between the curb and sidewalk in cities without causing damage to sidewalks and the like which are not constructed to support great weights.

The digging wheel comprises a pair of rotatably mounted metal rings 60. As shown in Figs. 1 and 3, these rings are maintained in spaced relation to each other by a plurality of digging buckets 6|. These buckets may comprise U-shaped metal plates, the ends of the U engaging the periphery of the rings 60, and may be secured in position by bars 62, which are indicated in the drawings as being welded to the sides of the buckets and as being secured to the sidewall of the rings by suitable bolts 63. For a more complete description of the digging bucket construction, reference may be had to Patent No. 1,927,323, issued to Vincent S. Penote, September 19, 1933.

The digging wheel is mounted between the two channel members 26 of the supplemental frame 25 as indicated in Figs. 1, 2 and 3. As there shown, the supporting frame 25 adjacent its rearmost or right hand end is provided with a transverse shaft 64, carrying a pair of flanged members or wheels 65 which engage the inner periphery of the rings 60 of the digging wheel. At the forward end of the supporting frame 25, a shaft I02 supports a flanged member 61 which similarly engages the inner periphery of the wheel. The wheel is maintained in contact with the flanged members 65 and 61 by a pair of flanged wheels 68, which are carried by struts 59 and secured to the frame 25, so that the flanged wheels 65, Bl and 63 are spaced in a triangular formation about the inner periphery of the digging wheel, thus maintaining it in position relative to the frame 25.

Also mounted on the frame 25 and extending transversely thereof and through the digging wheel is a conveyor 10, for ejecting the material which drops from the digging buckets during the digging operation. As shown in the drawings, this conveyor is supported by transverse frame members H which are secured to frame members 26 of the supplemental frame 25. The conveyor comprises a flexible belt 12 which is looped around pulleys or drums l3, rotatably journalled at opposite ends of the conveyor frame 1 The material removed from the trench by the buckets 6| is retained therein during the upward travel of the buckets (indicated by the arrow in Fig. 1) by a protecting plate 15. This plate is carried by the frame 25 and extends from the lower digging wheel supporting wheels 68 to a position substantially above the conveyor Ill, and bridges the gap between the two rings 66 which form the wheel. At its upper end the plate 15 is bent downwardly as indicated at 11, to guide the dug material from the buckets 8| onto the conveyor 15.

To insure ejection of the material from the digging buckets 6|, a bucket cleaner is provided. This cleaner is best shown in Fig. 1, and comprises a bar pivoted as at 8| to the framework 19 and maintained in the position shown in Fig. 1 by a. spring 82. The tension of this spring is such that under normal conditions the bar will be maintained in the position shown in Fig. 1, extending into the bucket, to cause material adhering thereto to be removed therefrom and fall ontothe conveyor I0. If, however, an unforeseen obstruction, suchas; for instance, a large piece of rock, may. become wedged in a bucket, the

ejector 80.n'1ay swing. clockwise about its pivot .(Fig. 1). and no. damage will .be done to either the ejector or any of the digging mechanism.

The digging wheel is rotated by the motor II. As shown in .the drawings, the motor extends longitudinally of the frame I and is provided with a clutch 9I which is interposed between the crankshaft of the motor anda drive shaft 90. The clutch may. be of any suitable type and is arranged tobe controlled by a clutch lever 92. The driving shaft 90 extends longitudinally of the frame and is supported by suitable bearings, such as that shown at 93 as being carried by the frame members 22, heretofore described. This shaft extends from the clutch 9I through a clutch box 94, containing a second clutch (not shown) but which is controlled by a lever 05. This second clutch selectively connects the driving shaft 90 with a shaft 96, which drives a differential driving unit contained within a differential housing 91. The cross shafts 98 of this differential unit extends outwardly at either end of the housing 91 and are each provided with a sprocket wheel 99. The sprocket wheels 99 are connected by respective driving chains I00 with a pair of sprocket wheels IOI which are secured to opposite ends of a counter shaft I02, which is journalled in suitable bearings I03 mounted on the frame 25, as shown in Fig. 3.

The driving chains I00 are of such length as to facilitate the raising and lowering of the supplemental frame 25, together with the digging wheel. As shown in Fig. 1, each of these chains is maintained taut by a pair of idler pulleys I02 and I03. Each idler sprocket I02 engages its respective chain I00, as indicated in Fig. 1, and is rotatably supported by an axle I04 carried by a plunger I05, mounted in a housing I06. A suitable spring (not shown) but contained within the housing, acts to maintain the plunger and therefore the sprocket in its uppermost position.

The other idler sprocket wheel, namely the sprocket wheel I03, rides on the top of the chain, as shown in Fig. 1, and this wheel is supported at one end of a lever I08, the other end of which is pivotally mounted on the spindle I04, which carries the idler sprocket I02, heretofore described. Suitable springs (not shown) but preferably carried by respective spindles I04 act to maintain their respective sprockets I33 in contact with the chains I00.

As heretofore mentioned, the digging wheel is driven from the shaft I02. As shown in the drawings, a pair of spaced driving gears IIO are drivingly secured to the shaft I02 and are arranged to mesh with the teeth I I I formed on the outer surfaces of the respective rings'60 of the digging wheel 26.

Tofacilitate the digging of a comparatively narrow trench the teeth I I I of the feeding wheel comprise pins which are press fitted to the wheel, as shown in Fig. 3, and thereafter welded in position, thus maintaining the overall width of the wheel at a minimum.

The flange member 61, heretofore mentioned as comprising one of the supports for the digging wheel, is rotatably mounted on the shaft I02, so that the weight of the digging wheel will not rest on the driving sprocket IIO. As shown in the drawings, the flanged member 61 comprises a sleeve which is rotatably mounted on the shaft I02, intermediate the two. driving gears H0. The. sleeve is provided with a: pair ofrend flanges I I5, which rotatablyengage annular recessesxl I6 formed in the adjacent driving gears, each flange I.I5.xbeing .provided with a. shoulder II'I against which theririgx60 ofthe digging wheel. bears. The arrangement thus described is such. that the flange supporting member 61. may rotate independentlyof the drivingwheel and thus compensating forthe difference in peripheral speeds ofwthe inner periphery. of the rings: 60: and the driving pins; HI of thedigging wheel. This construction greatly increases the life of all. of the coacting parts, especially the driving gear. H0 and the teeth III of the digging wheel, thus permitting-the teeth I. to be permanently secured to the wheel: without reducing the life thereon: I 7

The conveyor mechanism is" also. driven from the shaft I02. As shown in Fig. 3, a sprocket wheel. I20 is drivingly secured to the sprocket I0 I, heretofore described, and is connected by a driving c'hain. I2 I; with a sprocket, I22 mounted on a stubyshaft I23 journalled' in a bearing I24 carried' by one of theframe members 26 of the frame-25. The inner end. of the shaft I23is'provide'd with a bevelled gear I25, which meshes with a similar bevelled gear 126 on a cross-shaft I21 ournalled in a geanhcusing I28 carried by the conveyor frame 'I I The housing I28 contains gearing to enable the rotation of the conveyor in eitherdirection, that is, in the directiontomove the material to either side of the trencher machine. As shown, a gear I30 is splined: to the shaft I21 and is arranged to be moved to contact with a gear I28 on a shaft I29 carried by thehousing', or with an idler or reversing gear I30 which is also rotatably mounted-in the housing, and which constantly meshes with a gear I3I-, also secured to the shaft 1-29. The shaft I29 is provided at its outer end witha sprocket wheel which is connected by a driving chain I32 with a sprocket wheel mounted on a shaft I33 which carries one pair of belt supporting rollers='l3.

The: shifting of the gear E30 above described;

controls thedirection of the movement of the belt I2 and thus determines to which side of the machine the dirt is tobe ejected. This is accom- X plished by the movement of a shift lever I40. As shown in Fig. 3, the lever I40 is pivotallyconnected as at I4I- to a bracket I42, mounted on the gear box I28, and is connected by a link I43 with a plunger I44 slidably mounted in the gear box and arranged andadapted to coact with an annular recess I45 formed in the hub of the shiftable gear I30; to'shift' such gear into engagement with'either the gear I 28 or the gear I30 as desired; The lever I40 may also be moved to position the shiftable gear I30" to position intermediate the gears I28" and I30" and thus enable the conveyor to be disconnected from the driving mechanism.

The trenching machine is propelled during the trenching operation and on the road by the motor II. As shown in the drawings, the drive shaft 90, heretofore described is connected by a driving chain I-50,'with a shaft I5I, of a transmission unit hous'ed within a casing I52. The driven shaft I53 of this transmission unit is as shown in Fig. 5, as being connected by a universal joint I54 with a short shaft I55, which in turn is connected by'a universal joint I56 with a differential gear mechanism not shown but contained within a differential" housing The cross shafts I 59 of this differential. gear mechanism are connected to respective sprocket wheels I60, which, as shown in Fig. 5, extend at opposite sides of the trenching machine. The sprocket wheels I60 are'connected by'respective drive chains I6l, with driving sprockets I62 which are secured to respective driving sprockets I5 of the tractor treads and heretofore described. Normally the power applied to the differential gear unit acts with equal force on both tractor treads I6 to propel the trencher unit but by reason of such unit, which is similar to those used in automotive vehicles at the present time, permit the steering of the machine by a braking mechanism which selectively stops the revolution of either driving sprocket I60, as desired. As shown in the drawings, each sprocket I60 has secured to it a brake drum I10, encircling which is a brake band I1I pivotally mounted as at I12 on a cross-frame member I13. Each brake band is provided with a brake clamping mechanism, generally indicated at I14, and which may be of the usual type found in automotive vehicles. These brake mechanisms are actuated by rods I16 and I11, respectively, which are shown in Fig. 5 as extending rearwardly of the machine, and are pivotally connected to respective control levers I80 so that the brakes may be selectively operated to cause steering of the machine.

To enable the progressing of the machine at various road speeds, as wellas various digging speeds, a change-speed transmission gear mechanism is disposed between the drive shaft 90, and the differential unit, I58, which drives the tractor mechanism. This-transmission isbest illustrated in Figs. 5, 6 and 7. As there shown, the transmission ismounted in a substantially rectangular shaped housing I52 providedwith a pair of transversely extending internal walls 200 and 20I and opposite end walls 202 and 203.' The first unit of the change-speedtransmission is a reverse gearmechanism. The shaft I5I, heretofore mentioned as'being driven by the shaft 90 through the medium of the drive chain I50,'is'rotatably journalled in suitable anti-frictionbearings carried'by the intermediate wall 200 and ,the end wall 203 of the transmission housing. splined to this shaft is a gear 205 arranged to selectively engage a gear 206 or to drive a gear2I0, through the medium of a reversing gear 201, as indicated in Fig. 5. As there shown, the gears 206 and 2I0 are formed on a compound gear member 208, which is drivingly secured to a shaft 209; This shaftis rotatably journalled between the walls 200 and 203 of the housing, while the reversing gear 201 is journalled on-a stationary shaft 2, likewise rotatably mounted in the housing. The gears 206 and 201 are sospaced that an intermediate or neutral position for the gear 205 isprovided, and they are. arranged so that'the'shaft 209 is driven at the same speed, whenever the gear 205 is in driving engagement with the gea 206 or with the reversing gear 201. I

The position of the-shiftable gear 205 of the reverse gear unit'is controlled by a shift lever 212. This lever, as shownin Figs. 6 and 7,'is pivoted to a bracket 2I3 mounted on the top of the gear housing-and 'selectively'actuates a bar 2M which is'slidably mounted-in the housing. This bar engagesa lever 2I5 which actuates a slidably mounted bar 2| 6, "which in turn carries" a shifter fork 2I11. This fork 2l 1me,n, gages an annular recess '2I8 formed-in 'the. hub of the-gear 205, in; the usual manner.

1 The shaft,209, heretoforedescribed is arranged to be selectively coupled to a shaft 220 of: a change-speed gear unit of the transmission in such a manner as to drive such shaft at any one of a plurality of different speeds. As illustrated in Fig. 5, one end of the shaft 220 is journalled in the wall 20I of the gear housing, while the other end is journalled in a recess formed in the end of the shaft 200 heretofore described. A direct driving connection between the shafts 209 and 220 may be established with a shiftable gear 2 I9 which is splined to the shaft 220 and which is provided with internal teeth arranged to mesh with the external teeth 22I formed on the shaft 209. The splined connection between the gear 2I9 and the shaft 220 permits a sliding movement of such gear and enables it to be moved in or out of engagement with the gear 22I, thus enabling the direct driving connection to be selectively established.

When the direct driving connection between the shafts 209 and 220 is disconnected, other driving connections, to drive the shaft 220 at various reduced speeds may be selectively established. This shaft 220 is coupled, as hereinafter described, with the tractor tread driving mechanism. As illustrated in Fig. 5, a countershaft 222 is secured between the walls 200 and 20I of the gear housing, and a compound gear member 223 is rotatably mounted thereon. This compound gear member includes a gear 224 which constantly meshes with the gear 22I of the shaft 209, and three gears 225, 226 and 221 of differing diameters. The gear 225 is arranged to be selectively engaged by an external gear 228 which is formed on the shiftable gear member 2I9 heretofore described, while the gears 226 and 221 are arranged to be selectively engaged by gears 229 and 230 respectively, formed on a compound gear member 23I which is splined to the shaft 220. The shifting of the gear members 2I9 and 23I is controlled by the shift lever 232, carried by the gear housing. This lever selectively shifts the gear members 2I9 and 23I in a manner well known in automotive trans- InlSSlOnS.

The drive shaft 220 may be coupled directly with the tractor drive shaft I55 heretofore described, to drive the Member at road speeds to facilitate the movement of the machine from place to place when the digging mechanism is inactive. The establishment of such direct driving connection is made in a third unit of the transmission. As illustrated in Fig. 5, the shaft 220 extends through the wall 20I of the housing I52 into the hollow end of a shaft 234 thereby supporting one end of such shaft. The other end of the shaft 234 is journalled in the end wall 202 of the housing. Splined to this shaft is a shiftable gear member 236 having internal teeth arranged to clutchingly engage the external teeth of a gear 235 which is secured to the sha'ft 220, thus establishing a direct drive between the two shafts. Secured to the shaft 234 is a pinion 231 which meshes with a pinion 238 drivingly mounted on the shaft I53 heretofore described as being connected with the tractor belt drive mechanism.

The movement of the trencher, while the digging wheel is operating, is controlled through the reverse gear and change-speed gear units heretofore described. However the digging speeds are preferably considerably less than the driving or road speed. When operating in digging speeds, the direct drive connection between the shafts 220 and 234 is broken by shifting the gear member 236, Fig. 5, to the left. The shaft 234 isthen driven from the shaft 220 through a speed reduction gearing. As shown in Fig.

5, the gear235 of the shaft 220 is in constant me'sh'with a gear 239 of a compound gear unit 245 which -is journalled on the shaft I53 heretofore described. Carried by this gear member is a pair of relatively small gears 24l and 242 of difiering diameters. The gear MI is arranged to be engaged by the gear 236 when the latter is in its extreme left hand position, (Fig. The gear 242 is arranged to be selectively engaged by a gear 243 which is splined to the shaft 234. Thus, the shaft 234 may be selectively driven at either of two reduced speeds by the shaft 220.

The position of the gears 243 and 236 is controlled by a shift lever 250 pivoted as at 251' to the housing I52. The lower end of this lever is arranged to engage either of two slidably mounted bars 25f and 252. The barv 25l is provided with a shifter fork 253 which engages an annular groove in the hub of the gear 236 and controls the position of the same. The bar 252 is provided with a similar shifter fork 254 which similarly engages and positions the gear 243.

During normal digging operations the lever 252 is swung to a clock-wise position (Fig. 5) and thelevers 250 and 232 swing to any selected positions. Under these conditions, the drive is established through the gears 205, 207 and 210 of the reverse gear mechanism. This causes the machine to progress to the left as indicated by the arrow B, in Fig. 1. However, the lever 212 may be swung to the opposite direction to reverse the direction of movement of the machine should the same become desirable during the digging operation. When the machine is being propelled along the road or highway, from place to place with the digging wheel raised, its rate of travel is considerably greater than when the digging operation is taking place. Due to the balance of the machine, which is attained to reduce the weight thereof to a minimum, it is desirable that the direction of travel of the machine along the road with the digging wheel idle be such that the diggingwheel will be ahead of the operator relative to the direction of movement of the machine. In other words, it'is desirable that in road speeds the machine move only in a direction opposite to that indicated by the arrow B in Fig. 1.. An interlock is therefore provided between the levers 2 l 2 and 250 to prevent the movement of the machine 'at high or road speeds when the lever 212 is in its clock -wise position which would cause the machine to move in the direction of the arrow in Fig. 1. I

The interlock above mentioned is best illustrated in Figs. 6 and 7. As there shown, the shiftable bar 2! whichis operated by the lever 2l2 extends into the path of a pivoted arm 266. When the lever H2 is swung to a clock-wise position, the bar 234 swings the arm 280 into the position indicated by dotted lines in Fig. 6. In

this position, the arm 250, which abuts the end of the bar 25L causes such bar to be moved to the left (Fig. 6) assuring the movement of the gear 236 to a position out of engagement with the gear 235, thus preventing a direct driving connection between the shafts 226 and .234 and thereby preventing movement of the machine at high speeds in the direction of the arrow B in Fig.1.

Reference is made to our divisional application Serial No. 333,480 filed May 6, 1940, for

claims directed to the digging unit herein shown and'described".

We claim: v I

1 In a trenchingmachine, a frame carried by a propelling and supporting members, a motor on said frame, driving connections [between said motor, and said propelling; members, a guideway mounted on said frame adjacent one end thereof and extending upwardly and inwardly from said frame, a digging mechanism, a support for said digging mechanism, one end. of saidsupport beingpivotall'y and slidably mounted in said guideway .for relatively vertical movement thereon, means acting on said end of the support and op erated by said motorv to raise and lower said sup port, and means to supportthe other end of said support, said last .named means being arranged and adapted to raise and lower the same automatically in response to the movement of the pivoted end thereof and at a faster rate of speed.

2. In a trenching machine, a frame carried by propelling and supporting members, a motor on said frame, driving connections between said motor and said propelling members, said frame including horizontal frame members and u deway frame members, said guideway frame members being mounted adjacent one end of the horizontal frame members and extending upwardly and inwardly therefrom, a digging mechanism, a

carriage slidablymounted in said guideway, a

' support for-said diggingmechanism, one end of said support being pivotally mounted onsaid carriage and extending outwardly therefrom, means actingon the pivoted endof the support and operated by said motor to raise and lower said carriage, and means adapted and arranged to support and raise and lower the outer end of said supoprtautomatically in response to the raising or lowering of the carriage, said last named meanscomprising a flexible member having one end thereof securedto a relatively stationary frame member and extending outwardly to a pointadjacent-the outer end of the support and then inwardly and having'its other end secured to the upper end of said carriage.

3; In a trenching machine, a horizontal frame carried by propelling and supporting. members, a guideway frame mounted on. said horizontal frame adjacent oneyend thereof and extending upwardly therefrom, a. digging. mechanism, a supportfor said digging mechanism, a carriage slidably mounted in said guideway for relatively verticalmovement thereon, the inner end of said supportjbeing pivotally secured to said carriage, operating means acting on said carriage to raise andxlow-er the :inner end. of said support, and

means-to raise and lower the other end of said support automatically: and at a different. rate of speed than the rate-of's'peed'gof'the inner end of said support in response to the raising and lowering of the inner end thereof, said last named means comprising a flexible member having one end thereof secured to a relatively stationary frame member and extending upwardly to said carriage, thence outwardly to a point adjacent the outer end of the support and thence inwardly and having its other end secured to the upper end of said carriage.

4. In a trenching machine, a main frame including horizontal frame members and elevator frame members secured to one end thereof and inclining upwardly and inwardly therefrom, mobile supporting means for said frame, a carriage mounted for relative sliding movement in said guideway, a supplemental frame pivotally mounted on said carriage and extending outwardly therefrom, a digging unit mounted on said supplemental frame, power operated means to slide the carriagein said guideway, and means acting automatically in response to the sliding of said carriag in said guideway to swing the supplemental frame about its pivotal connection with said carriage at a faster rate of speed than the rate of speed of the sliding movement of the carriage.

5. In a trenching machine, a main frame including horizontal frame members, a guideway secured to one end of said frame members and extending upwardly therefrom, mobile supporting means for. said frame, a carriage mounted for an up and down movement in said guideway, a supplemental frame pivotally mounted on said carriage and extending outwardly therefrom, a digging unit mounted on said supplemental frame, power operated means to move the carriage up and down in said guideway, and a flexible member having one nd secured to the main frame, and extending upwardly therefrom to a sheave carried by said carriage and thence outwardly to a sheave carried by the supplemental frame adjacent its outer end and thence inwardly and having'its end secured to said carriage, whereby the outer end of the supplemental frame will be raised and lowered automatically in response to' the raising and lowering of said carriage and at a greater rate of speed than the rate of speed of movement of said carriage.

6. In a trenching machine, a frame carried by propelling and supporting members and including a pair of upwardly extending spaced guideway members mounted on said frame adjacent one end thereof, a digging mechanism, a support for said digging mechanism, the inner end of said support being pivotally and slidably mounted between said guideway members for relatively vertical movement thereon, hydraulic means disposed between said guideway members and connected between said frame and the inner end of the support, to raise and lower said support, and means disposed between th outer end of said support and the frame to raise and lower the outer end of said support automatically in response to movement of the inner end thereof and at a faster rate of speed.

'7. In a trenching machine, a main frame hav-' ing a pair of spaced guideway members secured to one end of said main fr e and extending upwardly therefrom, a hydraulic cylinder disposed between said members and having its lower end secured against movement relative to said frame, a piston in said cylinder and extendingupwardly therefrom, hydraulic pressure means'connected with said cylinder to raise and lower said piston, a carriage mounted between said guideway members for up and down movement therein, and a digging unit carriedby said carriage, said carriage being so constructed and arranged as to provide an enclosure for said piston rod and the upper end ofsaid cylinder regardless of the position of said piston rod thereby protecting the same against contact with the material dug by said digging unit.

8. A trenching machine, a main frame including an upwardly extending guideway carried by said frame, mobile supporting means for said frame, a carriage mounted for up and down movement in said guideway, a supplemental frame pivotally mounted on said carriage and extending outwardly therefrom, a trench excavating unit carried by said supplemental frame, power operated means to raise and lower said carriage in said guideway, and means movable by relativ movement between the carriage and the guideway to raise and lower the outer end of said supplemental frame at a greater rate of speed than the rate of speed of the movement of said carriage.

9. A trenching machine, a main frame including an upwardly extending guideway carried by said frame, mobile supporting means for said frame, a carriage mounted for up and down movement in said guideway, a supplemental frame pivotally mounted on said carriage and extending outwardly therefrom, a trench excavating unit carried by said supplemental frame, power operated means to raise and lower said carriage in said guideway, and means interconnected to said supplemental frame at a point remote from the carriage and to said main frame and adapted and arranged to be actuated by relative movement between the carriage and the guideway to raise and lower the outer end of said supplemental frame at a greater rate of speed than the rate of speed of the movement of the inner end of said supplemental frame.

10. A trenching machine, a main frame including an upwardly extending guideway carried by said frame, mobile supporting means for said frame, an elongated carriage mounted for up and down movement in said guideway, a supplemental frame pivotally mounted on the lower end of said carriage and extending outwardly therefrom, a trench excavating unit carried by said supplemental frame, power operated means to rais and lower said carriage in said guideway, and a cable extending from said carriage to the outer end of said supplemental frame and thence over the upper end of said carriage and downwardly to a fixed point on said main frame to raise and lower the outer end of said supplemental frame at a greater rate of speed than the rate of speed of the movement of the inner end of said supplemental frame.

VINCENT S. PENOTE. ALBERT R. ASKUE.

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