US2334717A - Scraper or like device and mechanism for operating the same - Google Patents

Description

C. A. LONG Nov. 23, 1943.

SCRAPER OR LIKE DEVICE AND MECHANISM FOR OPERATING THE SAME 6 Sheets-Sheet 1 Filed Aug. 25, 1940 INVENTOR @Am a. Z

Nov. 23, 1943.

c. A. LONG SCRAPER OR LIKE DEVICE AND MECHANISM FOR OPERATING THE SAME Filed Aug. 23, 1940 6 Sheets-Sheet 2 fly. 3.

m T N E V m C. A. LONG 6 Sheets-Sheet 3 Filed Aug. 25, 1940 Fig. '6.

INVENTORV 6M mi;

Nov. 23,, 1943.

SCRAPER OR LIKE DEVICE AND MECHANISM FOR OPERATTNG THE SAME 'Nov.23,1943. c. A. LONG 2,334,717

SCRAPER on LIKE DEVICE AND MECHANISM FOR OPERATING THE SAME Filed Aug. 23, 1940 e Shets-Sheet 4 INVENTOR Nov. 23, 1943. c. A. LONG SGRAPER 0R LIKE DEVICE AND MECHANISM FOR OPERATING THE SAME Filed Aug. 23, 1940 v 6 Sheets-Sheet 5 INVENTOR /immQZZZ 576 w $54 751.

C. A. LONG Nov. 23, 1943.

SCRAPER OR LIKE DEVICE AND MECHANISM FOR OPERATING THE SAME Filed Aug. 23, 1940 6 Sheets-Sheet 6 v INVENTOR Ka /L604 4 Elli) I NIX Patented Nov. 23, 1943 SCRAPER OR LIKE DEVICE AND MECHA- NISM FOR OPERATING THE SAME Charles A. Long, Oakmont, Pa., assignor to Blaw- Knox Company, Pittsburgh, Pa., a corporation of New Jersey Application August 23, 1940, Serial No. 353,860

16 Claims.

This invention is for a scraper for use in connection with the spreading of paving materials or for similar devices and is further for a mechanism for operating the scraper or other element.

In the copending application of Edward L. Harrington, Serial No. 324,755, filed March 19, 1940, there is disclosed an apparatus for use in the spreading of paving materials characterizedby the provision of a mobile frame adapted to be supported by rails at each side of the area to be paved with mechanism for propelling the machine along the rails as the paving advances. Said apparatus includes a trolley which moves back and forth on the frame in a direction trans verse to the direction in which the frame is propelled, and this trolley carries a scraper adapted to move the paving material back and forth over the area to be paved to spread the material before it is finally leveled by a screed which is also supported on the frame at the proper elevation. In the said application of Edward L. Harrington there is disclosed in one form of the machine, a drive for the trolley wherein the trolley is reciprocated by means of an endless chain continuously driven in one direction, and the chain is provided with a pin which is engaged with the trolley as it moves along the top and bottom reaches of th chain. This mechanism provides a simple form of drive for alternately moving a trolley back and forth along its guideway, and the present application is directed to such mechanism.

In thesaid application there is also disclosed one modification wherein the scraper comprises a plate carried at the lower end of a vertically extending post that passes through the trolley and has a bearing-in the trolley. As the trolley nears one end of its travel, an arm projecting-from the post strikes a cam on the frame of the machine" whereby further movement of the carriage causes the post to rotate, and the blade of the scraper is scraper against turning after it has been moved around the pile, and this latch remains operated until the trolley reaches its opposite limit of travel when the latch is released to enable the swinging movement of the scraper hereinbefore described to be effected. The present app1ica-,

tion is for this specific modification of the scraper and latching mechanism.

While the present application i described primarily in connection with paving apparatus as :disclosed in the said Harrington application,

the invention is not limited to us with paving machines but is applicable generally to any mechanism wherein a trolley is automatically moved back and forth along its guideway and is further applicable to any mechanism wherein there is an element corresponding to the scraperthat is to be turned and latched at each limit oftravel of the trolley on which it is carried.

The invention may be readily understood by reference to the accompanying drawings which Figure 4 is a fragmentary view showing a side elevation of the spreader and the arm by which it is turned;

Figure 5 is a transversetsection through the carriage and the'part of the machine which provides the runway 'for the'carriage, the view being inisubstantially the plane of line VV of.

Figure 6; V

Figure 6 is a horizontal'section through the ear ri-age, the view being in substantially :the plane of 1inelVI-'-VI of Figurer5;

Figure '7' is a fragmentary view showing the arrangement for raising and lowering the spreader; v

Figure 8 is a detailed view showing one of the gauges for indicating theelevation of the spread:-

Figure 9 is a'fragmentary view showing the" manner in which the chain engages the carriage for transmitting. motion to it, the chain "being shown in elevation and a portion only of the carriage being shown, partly in section and partly in elevation; Figure 10 is'a view similar to Figure 9 but viewtion .of thev carriage;

Figure 11 is a more or less schematic view showing the various positions of the spreader and the manner in which it is moved;

Figure 12 is a schematic view showing in detail the manner in which the position of the scraper is shifted as the carriage nears each limit of its travel;

Figure I3 is a fragmentary view showing a modified construction in which the spreader has two blades which are alternately brought into position as the direction of travel of the carriage is reversed; and

Figure 14 is a transverse vertical section in the plane of line XIV-XIV of Figure 13.

Referring first to the embodiment of the invention shown in Figures 1 to 12 inclusive, my invention is shown as being applied to a machine of the type disclosed and claimed in the said application of Edward L. Harrington, and only so much of the complete machine has been illustrated as is necessary for an understanding of the present invention. The machine comprises generally a frame 2 formed of structural metal supported on wheels adapted to ride along a track provided by the forms A at each side of the surface to be paved. Extending across the full width of the frame are two spaced- apart channel members 5 and 6 which form a runway for a carriage or trolley designated generally at 1. There is an open space 8 (see Figure 1) between the two channels 5 and 6 providing a clearance for the trolley and the parts which are carried thereon. As described in the said Harrington application, the machine is provided rearwardly of the trolley with a vertically adjustable screed which is designated 9 and which is shown only in Figure 11. In operation the machine is intended to travel along the tracks A in the direction of the arrow in Figure 1, and the carriage with the spreader moves back and forth as the machine advances to spread the material in advance of the screed,

The trolley 1 comprises a suitably constructed frame In which is provided on its forward side with two spaced-apart rollers H which have a rolling fit inside the forward channel 5, this channel providing a trackway for these rollers. The frame i is also provided with two flanged upper rollers l2. which ride on the top of the channel member 6 and with two flanged lower rollers which bear against the underside of the channel 6. This construction is best shown in Figure 5, and by this arrangement the trolley is supported for back and forth travel along the runway provided by the channels and 6, but is restrained from vertical movement.

The carriage or trolley is provided about midway of its length with a vertical sleeve 14. Passing through this sleeve is a rigid post l5. To the lower end of this post is secured a. scrapingv blade or spreader I5. The top of the post, as shown in Figure '7, is of reduced diameter and is fitted into a sleeve 16,. the sleeve l6 being externally threaded. The post [5 may turn within the sleeve IE, but it is restrained against endwise movement in one direction by the shoulder |5a thereon bearing against the bottom of the sleeve [6 and in the other direction by a thrust plate I! secured to the top of. the post. The sleeve IB is splined in the sleeve l5 so that it may move in a vertical direction while being held against rotation. This spline is secured'by providing a longitudinally extending key-way ill in the exterior of the sleeve I6 and providing a fixed key IS on the interior of the sleeve I 5 to engage in the keyway 18. A hand-wheel 26 having an internally threaded hub 2| is screwed onto the sleeve l 6 and forms a nut by means of which the sleeve l6 may be adjusted up or down by the turning of the hand-wheel, there being a bearing at 22 between the top of the sleeve M and the hub 2! of the hand-wheel 20. The hand-Wheel thus provides an arrangement whereby the scraper I3 may be raised and lowered by raising or lowering the sleeve 16. The scraper, however, may turn about the axis of the post l5 without turning the handwheel by reason of the fact that the post is rotatable within the sleeve l6 and the sleeve 16 is splined against rotation. For enabling the operator to readily determine the elevation of the scraper, the hub of the hand-wheel may be pro vided with upstanding strips 23 which have markings thereon as shown in Figure 8 reading in both directions from a zero position. The plate I! at the top of the post I5 provides an indicator which, in conjunction with the markers 23, enables the operator to know the elevation of the spreader at any time.

For moving the trolley back and forth there is provided an endless chain 25 extending along the inner face of the channel 6 and which passes around sprockets 26 and 2'1. The sprocket 23 is the driving sprocket and is carried on a shaft 28 on which there is also a sprocketwheel 29. The shaft 23 has fixed to it a disk 30 (see Figure 1), and a shear-pin 32 connects the sprocket 29 and the disk 3i) for transmitting power from the sprocket 29 to the shaft 28, and under conditions of overload the pin 32 will shear to prevent damage to the machine. The sprocket 29 is driven through a chain 33 and driving sprocket 34 connected to a source of power, not shown. The sprocket-Wheel 21 is supported on the channel 6 in such manner that it may be adjusted to a limited extent along the channel, there being an adjusting screw 35 for moving the block 33 on which the sprocket is supported to adjust the tension of the chain 25. The chain 25 is provided with a transverse pin 31 that projects from each side of the pin. Each end of this pin is provided with a flanged roller 31a. This pin is clearly shown in' Figures 6, 9 and 10.

Supported on the frame of the trolley is a vertically slotted guide 38 into which one end of the cross pin 31 is always entered. Opposite the guide 38 is a slotted upper guide 39 and a slotted lower guide 40, the guides 39 and 40 being directly opposite the guide 38. The other end of the pin 3! is adapted to extend into one or the other of the guides 39 and All, except at such time as the pin is moving around the sprockets 26 and 21. The arrangement is such that one end of the pin 3'! is always in the guideway 38 and the other end of this pin is either in the guide 39 or the guide 40 except at the time that the link carrying the pin 3'! is passing around one of the sprockets 26 or 21. When the pin 31 is moving along the upper reach of the conveyor, it moves the trolley in one direction. As it passes around one of the sprockets 26 or 21, its movement is principally in a vertical direction at which time it slides along the guides provided for it. and when it is in the lower reach of the chain, the trolley is of course moved in the reverse direction. The mechanism described provides a simple arrangement whereby the trolley may be moved back and forth along its runway while the chain 25 is driven continuously in one direction. In order to guide the pin 31' when it is passing around the sprocket and is between the upper and lower guides 39 and 43, the frame of the machine is provided as shown in Figures 1 and 2 with fixed guides 26a and 27a adjacent the sprockets 26 and 21 respectively, the purpose of which is to receive the end of the chain opposite the end which is engaged in the guide 38 and hold it from becoming twisted or being pulled out of line when the pin is going around the sprocket clear of either of the guides 39 and 43. The rollers 31a are provided for reducing wear and for lessening the shock which occurs when the pin passes from one of the guides on the carriage into one of the fixed guides 26a and 21a and when it passes from one of the fixed guides 25a or 21a into one of the guides on the carriage.

The operation of the pin may be seen by reference to Figures 9 and 10. In Figure 9 the pin 3! is engaged in the continuous guide 38 on that portion of the trolley which is at one side of the chain. The upper reach of the chain is moving continuously in the direction of the arrow. This, of course, causes the trolley to be carried toward the right as viewed in Figure 9 to the dotted line position. When the pin 31 is passing around the sprocket, its movement is principally in a vertical direction during which time the pin 31 rides down the guide 38. The trolley or carriage reaches its extreme limit of travel at the time when the guideway 38 is tangent to the sprocket. It is apparent that the trolley has to move past the shaft on which the sprocket-wheel is supported and it is for this reason that a continuous vertical guide 38 cannot be provided on the trolley on both sides of the chain. It is for this reason that the guides 39 and 43 are separated. This is clearly shown in Figure 5 where the support for the sprocket is shown as intervening between the guides 39 and 40.

Figure is similar to Figure 9 but shows the arrangement looking at the chain from the reverse face in which the pin 31 is engaged in the upper guide 33. When the trolley has been carried to the extreme limit of its travel indicated in dotted lines in Figure 10, the end of the pin 3'! which is engaged in the guide 39 slips from the guide 39 into the fixed guide 2111 and from the fixed guide 2111, moves directly into the lower guide 49 of the carriage. A simple and effective arrangement is thus provided for reciprocating the trolley through the use of a chain driven continuously in one direction. While I have specifically illustrated a chain and sprockets, it will be understood that these terms as used throughout are used in a generic sense as covering not only hains of various types but other endless flexible bands as cables, belts, and the like.

In the operation of the scraper, the scraper is dragged back and forth by the back and forth movement of the trolley on which it is mounted. As it nears each limit of its travel it is swung in such manner as to swing from one side of the material which it is pushing to the other side of the pile so that when the movement of the trolley is reversed the mass of material being pushed by the scraper will be carried along in the reverse direction. Preferably, as shown in Figures 1 and 11, the scraping blade I5 is at an angle to the direction of travel of the trolley so that it not only carries the material sidewise and back and forth across the area being paved, but also shoves it forwardly. As pointed out in the said Harrington application and as shown in Figure 11, the scraper is 'a predetermined distance in front of the screed so that the inner edge of the scraper determines the position of the toe of the excess material which will pile up in front of the screed.

For turning the scraper about the axis of the post I5, this post is provided with a horizontally projecting arm 4|. The forward end of this arm is provided with a roller 42 as best shown in Figures 3, 4, 5 and 6. The hub Me of the arm 4| is made in two halves which are bolted together. Within this hub are one or more keys 4|b, two of these keys being shown. These keys engage grooves He in the shaft P5. The upper end of the hub Me is flanged, the flange being designated 4|d and this flange engages a keeper 4|e secured to the bottom of the carriage for holding the hub at a fixed elevation. This arrangement enables the scraper l5 to be raised or lowered without changing the elevation of the arm 4| At the same time the keys hold the arm 4|"in fixed angular relation to the post l5 so that any movement of the arm 4| in a "horizontal plane is transmitted to the scraper, the construction in effect providing a spline between the crank 4| and the post IS. The hub 4|a is of course made in two parts in order to enable the parts, including the keys, to be assembled. Secured to the underside of the frame of the machine forwardly of the runway for the trolley and spaced inwardly from each end of the runway, are fixed abutments or striking plates 42a and 4%. These may be formed simply from pieces of angle iron r welded to the underside of the frame of the ma- The manner in which the scraper is operated may be clearly seen by reference to Figure 11 in which the full-line position of the trolley is shown at the center of the runway, and it is moving in the direction of the arrow. When the trolley has moved a sufficient distance toward the right as viewed in Figure 11, the roller 42 will strike the abutment 42a, the parts then being in the position shown at X in Figure 11. The trolley will continue to move toward the right, but as the arm is engaged by the abutment 42a and cannot move further in this direction, the further movement of the trolley will cause the arm 4| to transmit a rotating motion to the post l5 causing the inner edge of the scraper to move away from the screed in the direction of the chain of arrows shown in Figures 11 and 12. At one position in its movement, the scraper will be parallel with the screed, as shown in the dotted line position X in Figure 12. Further movement of the trolley toward the right as viewed in Figure 9 causes this rotary motion of the post to be continued until the position of the scraper has been exactly reversed and the scraper is then in the position shown at X in Figures 11 and 12. The stop or striking plate 42a is so positioned that the reversing movement of the scraper will be completed just at the time the trolley is at the furthest limit of its movement toward the right as viewed in Figure 11. been moved to the position X the pin 3? on the chain will just be at the midway in its travel around the sprocket and the trolley will be at the extreme limit of its movement. The movement of the trolley will then reverse and the.

When the scraper has scraper will be dragged toward the left until the roller 42 engages the striking plate 422), and as the travel of the trolley continues toward the left, the blade will be. again reversed to the position shown at X3, the same operation of the scraper taking place at eachend of the limit of travel of the trolley but in the opposite direction. It will be observed that the trolley is moving as the position of the scraper is changing so that the scraper, in swinging into the position shown at X in Figure 12 and then moving further to the reverse position, travels from one side of the material which it is carrying along with it to the other side of this pile. The fact that the turning movement occurs while the trolley is still moving, is desirable as it causes the spreader to sweep around. the pile of material as it turns. The length of travel of the trolley and the position of the striking plates 42a and 42b is such that the tip of the scraping blade, when moving along the line of the succession of arrows in Figure 12, sweeps quite close to the rail A thus assuring the spreading of material close to the rails, some of the pile of loose material being swept around with the edge of the scraper as the swinging movement of the scraper takes place.

In order to hold the scraper from changing its position except adjacent the limits of travel of the trolley, my invention also provides a latch mechanism. In the embodiment of the invention illustrated in Figures 1 to 12, there are two similar latch elements 43 carried on the trolley, one at each side of the forward edge of the trolley. These, latch elements are best shown in Figures 3 and 6. Each comprises a lever pivoted between its ends at 44. The two latches face in opposite directions and the inner end of each is provided with a pawl-like terminal portion 43a and each has an operating extension 43b. Each latch is biased by a spring 45 which tends to urge the latch terminal 43a thereof downwardly. The arrangement is such that the arms 4|, when swinging from one position to the other, will ride under the pawl-like terminal 43a of the latch, camming it up against the biasing force of the spring 45 until the shoulder 430 of the latch snaps over the arm 4 l. One or the other of these latches holds the arm to prevent the scraper from being turned at all times except at the moment when the latch is tripped to enable the scraper to swing from one position to the other. For tripping the latch to release the arm at the moment when the scraper is to be turned, there are provided on the underside of the frame of the machine, two oppositely faced cam elements 46a and 4%, these being adjacent the stop plates 42a and 422) respectively. One of these cam blocks is clearly shown in Figure 3. Each operating extension 4317 of the latches 43 is provided with a roller 43d. As best shown in Figure 3, when the roller 42d at the left-hand side of the trolley engages the cam 48d, the latch which is shown as being engaged with the arm 4| will be tripped due to the engagement of the roller 43d with the incline 45a to rock the lever 43 and release the latch. This releasing movement will occur just before the roller 42 on the arm 4| hits the striking plate 42a.

When the scraper is nearing the opposite limit of its turning movement after it has been released, the arm 4| will engage under the other latch, which in Figure 3 would be the right-hand latch, and the scraper will thus be latched in its opposite position as the swinging movement of the scraper is completed.

' The mechanism described thus provides an ideal form of scraper for use with a spreading machine of the character disclosed in the Harrington application wherein the scraper is caused to move back and forth between two side rails as the machine advances forwardly along the rails and the scraper is caused to sweep around the pile of material as each limit of travel is approached. The mechanism provides a simple construction whereby the scraper is latched except when it approaches the two limits of travel of the trolley when it is to be released and turned so that as the trolley travels back and forth between its limits of movement, the scraper is held always in the proper angular position. It should be pointed out that stops are provided on the trolley at 41 (see Figure 6) against which the arm 4| will bear when the arm is latched in position, there being one of these stops at each limit of movement of the arm so that the arm and hence the scraper is held in the proper angular position, being confined against the stop by the latch.

In the modification shown in Figures 13 and 14, the scraper element is provided with two blades, one of which moves down into operating position as the other one is elevated. These blades are spaced-apart a suflicient distance so that as one of them lifts up at one side of the material, the other one will come down on the opposite pile of material which is being pushed along by the scraper. In these figures only so much of the trolley has been shown as is necessary to illustrate the construction. In these figures, 5 designates one of the two channels previously described forming the runway for the trolley, and 5 is the other of these two channels. The trolley comprises a metal structure 48 having rollers 49 thereon that travel inside the channel 5. This trolley frame is also provided with upper rollers 50 which ride on top of the channel 6 and rollers 51' that ride under the channel 6, the general arrangement being similar to that previously described in connection with Figures 5 and 6.

Mounted on the top of the trolley structure 48 are supports 52 in which is mounted a rock shaft 53. Secured to the shaft 53 are two arms or walking beams 54. Pivotally hung from one end of each of the arms 54 are bars 55 and to the lower end of the bars 55 is secured a scraper plate 56. Similarly hung from the beams 54 are bars 5'! to which is secured a scraper or spreader 58. Mounted on the underside of the carriage is a shaft 59 which carries two beams 60 which are parallel with the beams 54 and which are also pivotally connected to the bars 55 and 51 as clearly shown in Figure 13. The two spreaders 55 and 58 are thus supported on a parallel linkage in such manner that when one spreader is down the other is up.

Mounted in the trolley frame 48 is a sliding cross-head 6| of C-shaped cross section having a backing plate 62, top plate 53, bottom plate 64, and on the bottom plate 64 is an upright 65 and on the top plate 63 is an upright 65.

On the rear of the plate 62 is a guide fil forming a vertically elongated groove. Secured to the rock shaft 53 is an arm 68 having a roller 69 thereon which is received in the groove provided in the guide Bl. On the front of the plate 62 is a vertical guide slot 10, and in each of the uprights 55 and 66 are slots similar to the slots 39 and 40 in Figure 10.

Both the upper and lower reaches of the chain H, which is in all respects similar to the chain 25 previously described, pass through the crosshead 6 I. The chain is provided with a transverse pin 12 with rollers on the extremity thereof similar to the rollers on the pin 31.

In the arrangement shown in Figures 13 and 14, it may be assumed that the chain travels in the direction of the arrow shown in Figure 13. In this figure the upper reach of the chain is moving toward the right and the transverse pin 12 is engaged in the slots in the sliding cross-head. The pin or the chain tends to slide the cross-head in the trolley toward the right as viewed in Figure 13, and the relative movement of the cross-head in the trolley transmits movement through the guide 61 and roller 69 to the arm 68 and to the rock shaft 53 to lower the scraper 56. When the scraper or spreader 56 is in its lower position and further rocking movement of the arms 60 cannot take place, the continued movement of the chain will then cause the trolley as a unit to be moved along. When the trolley reaches the righthand limit of its travel as viewed in Figure 13, the pin 12 and the chain will pass around the right-hand sprocket in the manner previously described in connection with the construction shown in Figures 1 to 12. As the pin 12 moves along the bottom reach of the chain, the cross-head 6| will be pulled in the opposite direction. This relative movement of the cross-head in the trolley will serve to reverse the position of the scraper blades 56 and 58. When the scraper blade 58 has been lowered and further relative movement of the cross-head in the trolley has stopped, the trolley as a unit will then be dragged along in the reverse direction.

The length of the chain and the position of the sprockets is so calculated that the scraper 58 will descend closely adjacent the right-hand rail A at one side of the road-bed and the blade 56 will descend adjacent the other side rail.

In both embodiments of the invention as herein described, a chain moving continuously in one direction is utilized for transmitting reciprocating rectilinear motion to the trolley. In both forms of the invention the trolley frame carries a spreading means which, at the limits of movement of the trolley, moves from one side of the pile of the material which is being shoved back and forth by the opposite sides. In the modification shown in Figure 13, the scrapers 56 and 58 are illustrated as being parallel, but it will be understood that they may be set at an angle to each other to impart a forward motion to the material in the same way that the inclined scraper shown in Figure 1 imparts forward movement to the material. In both forms of the invention the operation of the trolley and the movement of the scraper with respect to the material is accomplished by a driving chain which operates continuously in one direction. As previously pointed out, the scraper and mechanism herein described is particularly useful in connection with a machine as illustrated in the Harrington application wherein a scraper is moved back and forth in front of the screed to distribute the paving material in advance of the screed as the spreading machine is moved forwardly along the roadbed.

-. While I have illustrated and described certain specific embodiments of my invention, it will be understood that this is by way of illustration and not by way of limitation and that various changes and modifications may be made within the contemplation of my invention and under the scope ofthe following claims.

I claim as my invention:

1. Scraping means for road-building machines wherein the machine is provided with a frame forming a runway, a carriage movable along the runway, a scraper suspended from the carriage for movement in a horizontal are from one working position to another working position, means for moving the carriage back and forth, means for effecting the movement of the scraper from one position to th other as it approaches the limit of movement of the carriage and while the carriage is still moving, said means being arranged to complete the movement of the scraper as the limit of movement of the carriage is reached whereby the scraper sweeps around the base of the pile of material which it has been pushing as it approaches and reaches the limit of its travel in either direction, and latching means controlled by the movement of the carriage for holding the scraper in the position to which it is turned during the travel of the carriage toward the opposite end of the runway.

2. A spreading mechanism for road-building machines wherein the machine is provided with a frame forming a runway, said spreading mechanism comprising a carriage movable back and forth along the runway, means for driving the carriage back and forth along the runway, a vertical post pivotally carried in said carriage and depending therefrom, a scraper having a working face thereon carriedby said post, means connected with the scraper for rotating the scraper about the axis of said post, and abutments on the frame with which said means cooperates whereby such rotation of the scraper is e ifected at predetermined positions in the path of travel of the carriage, said means and abutments being in engagement during the travel of the carriage for a sufficient interval of such travel as to cause the working face of said scraper to be substantially reversed end for end.

3. A spreading mechanism for road-building machines wherein the machine is provided with a frame iorming a runway, said spreading mechanism comprising a carriage movable back and forth along the runway, means for driving the carriage back and forth along the runway, a vertical post pivotally carried in said carriage and depending therefrom, a scraper having a working face carried by said post, means on the frame of the machine near each limit of travel of the carriage forming an abutment, and means carried by said post for contact with said abutments for causing the post to be turned suflicient to reverse the direction in which the said working face is turned when said means engages either of said abutments and while the carriage is moving whereby the continued movement of the carriage swings the scraper through a horizontal arc as the carriage approaches the limits of its travel.

4. A spreading mechanism for road-building machines wherein the machine is provided with a frame forming a runway, said spreading mech anism comprising a carriage movable back and forth along the runway, means for driving the carriage back and forth along the runway, a vertical post pivotally carried in said carriage and depending therefrom, a scraper carried by said post, means on the frame of the machine near each limit of travel of the carriage forming an, abutment, means carried by said post for contact,

with said abutments for causing the postto be turned when said means engages eitherof said abutments and while the carriage is moving whereby the continued movement of the carriage swings the scraper through a horizontal are as the carriage approaches the limits of its travel, latch means on the carriage for holding the scraper from turning, and means on the frame of the machine for releasing said latch means when the scraper is to be turned.

5. A mechanism of the class described comprising a supporting frame providing a runway, a carriage movable back and forth along the runway, a vertical post suspended from the carriage, a scraper on the vertical post having a working face thereon, an arm projecting from the post, an abutment on said frame near each end of the runway in the path of travel of said arm whereby when the carriage approaches the limit of its travel one of the abutments engages said arm to rotate the post and swing the scraper through a limited horizontal arc sumciently to reverse the direction in which said working face of the scraper is turned, and means for moving the carriage back and forth along the runway.

6. A mechanism of the class described comprising a supporting frame providing a runway, a

carriage movable back and forth along the run- 7 way, a vertical post suspended from the carriage, a scraper on the vertical post, an arm projecting from the post, an abutment on said frame near each end of the runway in the path of travel of said arm whereby when the carriage approaches the limit of its travel one of the abutments engages said arm to rotate the post and swing the scraper through a limited horizontal arc, a pair of latches on the carriage for cooperation with said arm, one latch engaging the arm at one limit of movement of the scraper and one engaging the arm at the other limit of movement of the scraper, means on the frame near each limit of travel of the carriage for releasing the latch which is holding the arm about the same time the arm engages one of said abutment-s, said latches serving to hold the scraper from turning except at the limits of travel of the carriage, and means for driving the carriage.

7. A trolley mechanism of the class described comprising a runway having a trolley movable therealong, an endless chain having parallel reaches driven in one direction only for transmitting reciprocable rectilinear movement to the trolley, a guideway on the trolley extending in a direction crosswise of the chain, and means on the chain received in the guideway through which motion is transmitted from the chain to the trolley, said 'means being engaged in one end of the guideway when it is in one reach of the chain and in the opposite end of the guideway when it is in the other reach of the chain, said means traveling along the guideway when it is moved from one reach to the other.

8. A mechanism of the class described comprising a runway, a trolley movable along the runway, an endless flexible member extending in parallel reaches along the runway, mean adjacent each end of the runway about which the flexible member is looped, means for driving the flexible member in one direction only, a guideway on the trolley transverse to the direction of travel of the trolley and transverse to the reaches of the endless flexible member, and means on the endless member slidably engaged in the guideway for driving the trolley back and forth, the lastnamed means moving along the guideway as it is carried around said means about which the endless member is looped.

9. A trolleymechanism of the class described comprising a frame structure constituting a run= way, a trolley movable along the runway, a sprocket adjacent the opposite ends of therunway, an endless chain passing around the sprockets and extending in parallel reaches along the runway, driving means for operating the chain continuously in one direction, a projection .on the chain, and a guideway on the trolley extending crosswise of the direction of travel of the trolley and crosswise of the reaches of the chain into which said projection extends and along which it moves when the portion of the chain carrying said projection is traveling around the sprockets.

10. A trolley mechanism of the class described comprising a frame structure, constituting a runway, a trolley movable along the runway, at sprocket adjacent the opposite ends of the runway, a chain passing around the sprockets, a driving means for operating the chain continuously in one direction, a transverse pin on the chain, and a guideway on the trolley extending crosswise of the direction of travel of the trolley into which the pin projects and along which the pin moves when the portion of the chain carrying said pin is traveling around the sprockets whereby the carriage is moved in one direction as the pin travels along one reach of the chain and in the opposite direction as the pin travels along the other reach of the chain, and the pin moves along said guideway when the portion of the chain on which it is carried is traveling from one reach to the other.

11. A trolley mechanism of the class described comprising a frame structure, constituting a runway, a trolley movable along the runway, a sprocket adjacent the opposite ends of the runway, a chain passing around the sprockets, a driving means for operating the chain continuously in one direction, a transverse pin on the chain, and a guideway on the trolley extending crosswise ofthe direction of travel of the trolley into which the pin projects and along which the pin moves when the portion of the chain carrying said pin is traveling around the sprockets whereby the carriage is moved in one direction as the pin travels along one reach of the chain and in the opposite direction as the pin travels along the other reach of the chain, and the pin moves along-said guideway when the portion of the chain on which it is carried is traveling from one reach to the other, said guideway being formed on the trolley in such manner that the chain is between opposed portions of the guideway, the pin projecting from two sides of the chain to engage the guideway at each side of the chain, a portion of the guideway on one side of the chain being discontinuous so that the trolley may pass by the sprocket-wheels, the arrangement being such that one end of the pin will clear such discontinuous portion of the guide during a portion of the travel of the pin around the sprocket-wheel.

12. A trolley mechanism of the class described comprising a frame structure, constituting a runway, a trolley movable along the runway, a sprocket adjacent the opposite ends of the runway, a chain passing around the sprockets, a driving means for operating the chain continuously in one direction, a transverse pin on the chain, a guideway on the trolley extending cross,

wise of the direction of travel of the trolley into which the 'pin projects and along which the pin moves when the portion of the chain carrying. said pin is traveling around the sprockets whereby the carriage is moved in one direction as the pin travels along one reach of the chain and in the opposite direction as the pin travels along the other reach of the chain, and the pin moves along said guideway when a portion of the chain on which it is carried is traveling from one reach to the other, said guideway being formed on the trolley in such manner that the chain is between opposed portions of the guideway, the pin projecting from two sides of the chain to engage the guideway at each side of the chain, a portion of the guideway on one side of the chain being discontinuous so that the trolley may pass by the sprocket-wheels, the arrangement being such that one end of the pin will clear such discontinuous portion of the guide during a portion of the travel of the pin around the sprocket-wheel, and fixed guide means on the frame adjacent each sprocket for receiving the end of the pin at such time that the end of the pin is clear of the discontinuous guide on the trolley.

13. A trolley mechanism of the class described comprising a frame structure, constituting a runway, a trolley movable along the runway, a sprocket adjacent the opposite ends of the runway, a chain passing around the sprockets, a driving means for operating the chain continuously in one direction, a transverse pin on the chain, a guideway on the trolley extending crosswise of the direction of travel of the trolley into which the pin projects and along which the pin moves when the portion of the chain carrying said pin is traveling around the sprockets whereby the carriage is moved in one direction as the pin travels along one reach of the chain and in the opposite direction as the pin travels along the other reach of the chain, and the pin moves along said guideway when a portion of the chain on which it is carried is traveling from one reach to the other, said guideway being formed on the trolley in such manner that the chain is between opposed portions of the guideway, the pin projecting from two sides of the chain to engage the guideway at each side of the chain, a portion of the guideway on one side of the chain being discontinuous 50 that the trolley may pass by the sprocket-wheels, the arrangement being such that one end of the pin will clear such discontinuous portion of the guide during a portion of the travel of the pin around the sprocket-wheel, and fixed guide means on the frame adjacent each sprocket for receiving the end of the pin at such time that the end of the pin is clear of the discontinuous guide on the trolley, each end of the pin having a roller thereon for cooperation with the guides.

14. A trolley mechanism of the class described comprising a frame structure constituting a runway, a trolley movable along the runway, a sprocket adjacent the opposite ends of the runway, a chain passing around the sprockets and extending between the sprockets along the runway in parallel reaches, driving means for operating the chain continuously in one direction, a projection on the chain, a guideway on the trolley extending crosswise of the direction of travel of the trolley and crosswise of the direction of the reaches of the chain into which said projection extends and along which it moves when the portion of the chain carrying said projection is traveling around the sprockets, whereby the trolley is moved back and forth along the runway while the chain is driven continuously in one direction, scraper means carried by the trolley movable in a horizontal plane from engagement with one side of a pile of material being spread by the scraper to the opposite side of such pile, and means for so moving the scraper adjacent the limits of movement of the trolley.

15. A trolley mechanism of the class described comprising a frame structure constituting a runway, a trolley movable along the runway, a sprocket adjacent the opposite ends of the runway, a chain passing around the sprockets and extending between the sprockets along the runway in parallel reaches, driving means for operating the chain continuously in one direction, a projection on the chain, a guideway on the trolley extending crosswise of the direction of travel of the trolley and crosswise of the direction of the reaches of the chain into which said projection extends and along which it moves when the portion of the chain carrying said projection is traveling around the sprockets, whereby the trolley is moved back and forth along the runway while the chain is driven continuously in one direction, scraper means carried by the trolley movable in a horizontal plane from engagement with one side of a pile of material being spread by the scraper to the opposite side of such pile, and means deriving its power from said chain for so operating the scraper adjacent the limits of movement of the trolley.

16. A scraping mechanism comprising a frame with a runway, a carriage movable back and forth along the runway, a scraper having a working surface suspended from the carriage and rotatable about a vertical axis relative to the carriage, means for moving the carriage back and forth, and means adjacent the limits of travel of the carriage for effecting rotation of the scraper about said axis while the carriage is in motion and through an are which reverses the direction in which the working surface of the scraper faces, said means being positioned to complete such rotation of the scraper as the carriage reaches its limits of travel.

CHARLES A. LONG.

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