US2593606A - Block-bisecting machine - Google Patents

Description

A ril 22, 1952 M. R. PRICE 2,593,606

BLOCK-BISECTING MACHINE Filed Feb. 21, 1950 s Sheets-Sheet 1 x g! g l 60 l Ill \ Jol 3/ 2 3 2s 2a a 5 t o INVENTOR.

Mn. TON R. PE/CE A TTORNFY M. R. PRICE April 22, 1952 BISECTING MACHINE BLOCK- 6 Sheets-Sheet 2 Filed Feb. 21, 1950 -Inn INVEN TOR. M/L ro/v A. PRICE A T'TORNE'Y April 22, 1952 M. R. PRICE BLOCK-BISECTING MACHINE 6 Sheets-Sheet 3 Filed Feb. 21, 1950 INVENTOR. M/L TOA/ R. PIP/CE.

A TroRA/EY April 22, 1952 M. R. PRIE BLOCK-BISECTING MACHINE Filed Feb. 21, 1950 INVENTOR.

M/L TON R. PRICE A TTORNEY M. R. PRICE April :22, 1952 BISECTING MACHINE BLOCK 5 Shuts-Slide: 5

Filed Feb. 21, 1950 8 -"BIB-ala-BI lalalelulelawulahal nsl INVENTOR. 1 1/4 ro/v R. PRICE A r TORNbY April 22, 1952 M. R. PRICE 2,593,606-

BLOCK-BISECTING MACHINE BY 1- g -1 'iZ- A r TOR/V6 Y Patented Apr. 22, 1952 BLOCK-BISECTING MACHINE Milton R. Price, Issaquah, Wash, assignor of onehalf to Orville E. Gibson, Seattle, Wash.

Application February 21, 1950, Serial No. 145,461

20 Claims. 1

This invention relates to the treatment of precast blocks of concrete aggregate, preferably although not necessarily concrete blocks containingpumice, and aims-to produce therefrom building. bricks having a pronounced roughening of the surface upon one face thereof. In the actual work of laying the bricks in the several courses of' a masonry wall this rough face is exposed to view and gives to the finished wall an appearance generally considered more attractive than a smooth-faced brick. According to the present process the procedure is one in which the block being processed is first pre-cast to a fore-and-aft width twice the width of the building brick which is to be made therefrom, and the block is then bisected on its longitudinal median line. It is through the medium of this bisecting step that I am enabled to achieve the end result desired.

The objectof the invention, generally stated, is to provide" a simple and effective process for making a concrete building brick with a rough-' finish face; and? to devise apparatus suitable for carrying theprocess into practice. Other objects and advantages will appear in the course of the following description and claims, the invention consisting in the novel process and in the construction, adaptation and combination of the p'art'soff a machine for practicing said process.

Clarity in an understanding of the several views of the drawings will perhaps be advanced byherepointing out that the concrete building bricks which I produce are made in two thicknesses; The thickerof' these bricks is intended to simulate a hand-hewn' building stone and the roughening'effectshould therefore'be' quite irregular; The thinner brick, on the other hand, finds its" appeal from its similarity to a"Roman' t'ype clayb'rick' which'is'peculiarized by the fact that rough surface presents multiple albeit more or" lessirregular ridges running lengthwise of the face. A somewhat" different treatment of the pre cast blocks is necessary in order that these two efl ects may'be obtained. With this understanding in mind, the several views of the drawthe machine is here shown equipped to produce the thinner bricks.

Figs. 5 and 6 are fragmentary longitudinal vertical sectional views showingopposite ends of the machine and which, taken together, portray the complete-structure. The scale here employed is enlarged from that of the preceding views, and broken lines are employed to represent thin blocks in course of being processed into bricks.

Fig. 7 is a fragmentary transverse vertical sectional view taken to an enlarged scale on line 'l-1 of Fig. 5.

Figs. 8 and 9 are. views similar to Figs. 7 and 5, respectively, excepting that the machine-as here shown is arranged and adapted for the production of the thick type of brick.

Fig. 10 is a perspective view of the pre-cast thick block.

Fig. 11 is a perspective view illustrating the products of the bisecting. step performed upon said thick block.

Fig. 12 is a perspective view of the pre-cast thin block and showing the same as having been scored along top and bottom faces preliminary to bi'secting; and

Fig. 13 is a perspective view illustrating the products of the bisecting step performed upon the scored thin block.

Referring to said drawings, the numeral 20 denotes an endless chain serving as one of two associated conveyors provided in the present machine for carrying successive pre-cast blocks of concrete along a travel path leading to a platform on which the work of bisecting the block is performed; This conveyor chain works about sprocket wheels 2| and 22' located at the head and tail ends thereof and at regularly spaced intervals of the length presents upstanding flights 23 which act to engage and propel the blocks along the length of the chain. Such chain extends for only a portion of the length of the machine, and the work then passes onto the other conveyor to give to the block the full travel necessary' to reach'the bisecting platform. The second conveyor" comprises twin endless chains 24 which pass about respective head and tail sprocket wheels 25 and 26 and work in longitudinal planes located one at one side and the other atthe other side of the plane occupied by the firstmentioned chain. It will be here noted' second said conveyor. Flights for the twin chains, and which are given a wider spacing than the flights 23, are denoted by 29. To distinguish the two conveyors, I will hereinafter term the first mentioned conveyor as the low-speed conveyor and the second said conveyor as the highspeed conveyor, these terms being comparative only and reflecting different speeds at which the chains are driven and the purpose of which will be hereinafter set forth.

To complement the first or low-speed conveyor in giving firm support to the edges of the blocks as they are fed longitudinally thereof there is provided along one side of the machine a ledge 30 and along the opposite side there are provided a series of rollers 31 aligned horizontally with the ledge and journaled for free rotation about transverse axes. The twin chains of the high-speed conveyor are desirably so placed as to themselves give suficient stability to the blocks but they may, if desired, be complemented by a ledge or ledges along the sides. Both sides of the machine present rails, as 34 and 35, projecting above the conveyors and defining a confined walk-way slightly wider than the width of the blocks, and within the length of one said rail at a point more or less central to the run of the low-speed conveyor there is provided an outjutting pocket 35 and received in this pocket and yieldingly urged inwardly by springs 31 into the path travelled by an edge of the conveyed blocks are two pressure shoes 40 and 4| hinged as at 42. It is the purpose of these hinged pressure shoes to bring the conveyed blocks firmly to bear against the opposite rail 34, at which point in their travel the blocks traverse two abrasive discs, as 32 and 38, one located above and the other below the travel path of the blocks. The discs are fixedly carried upon the arbors 38' and 39 of respective electric motors 43 and 44, and in order that the discs may be made active or inactive at will said motors seat upon respective hinged tables 45 and are moved vertically by a related adjusting screw 46 into and out of positions whereat the lower said disc scores the underside and the upper said discscores the upperside of the conveyed block. As heretofore pointed out, the scoring step is performed only upon the thin blocks.

Leaving the successively acting conveyors, the block, thick or thin as the case may be, is projected forwardly onto the bisecting platform, this action being one of bringing the block to a stop upon the platform and being accomplished by having the high-speed flights reach and pass around the tail sprocket wheels 26 as the related block reaches a centered position upon the platform. The significance of giving the second said conveyor an accelerated travelling speed by comparison with the first said conveyor will now become apparent when it is here again pointed out that the spacing between the flights 29 is wider than that of the flights 23. I find that a 3 to 1 speed ratio, and a corresponding difference in the spacing of the flights, is satisfactory for my purpose. cessive open spaces on the high-speed conveyor unoccupied by any block, and it is in the time interval which these open spaces provide that the step of bisecting the block previously de- By this arrangement there will be suc- Describing now said platform and the mechanism by which bisection is accomplished, it will be seen from an inspection of the related Figs. 3 and 9 and 4 and 5, respectively, that the platform proper comprises two sets of longitudinally extending series of rollers 50 and 5| journaled for free rotation about transverse horizontal axes and supported in the instance of one said series by an angle-iron 52 placed at one side of the median longitudinal line of the platform and in the instance of the other said series by an angle-iron 53 placed parallel thereto at the opposite side of said median line. To provide a floating support for these angle-irons the same present pendant guide rods 54 at each of the two ends and these rods receive a vertical slide mounting in brackets, as 55 and 56, rigid with the framework of the machine. Springs 5! surrounding the guide rods exert upward pressure upon the angle irons to yieldingly maintain the rollers on a given level.

Along each side of the platform and disposed to occupy positions in substantial alignment with the walk- way rails 34 and 35 and thus constituting substantial prolongations of the latter there is provided a respective wall-forming plate, as 58 and 59. Each such side plate is mounted in much the same manner as the angle-iron roller mounts, and which is to say that each plate has guide rods 60 rigid therewith and has springs 5i surrounding the rods to yieldingly urge the side plates inwardlywithin limits imposed by jam-nuts 62, the guide rods being in this instance journal-mounted from the frame for horizontal sliding movement. At the admission end of the platform each side plate flares outwardly, as at 63, to guide the forwardly projected blocks onto the platform.

Reverting to the brackets, it will be seen that one of these frame-carried members, and namely the bracket 56, extends inwardly to substantially the longitudinal median line of the platform whereat there is presented a vertical flange 64 bored transversely at spaced intervals of the length to provide bolt-holes. Bolts 65 for these bolt-holes act to detachably and rigidly secure, alternatively, either of two longitudinal blades 66 (Figs. 3 and 9) or 61 (Figs. 4 and 5). Both of said blades occupy a vertical longitudinal plane and extend by their upper edge to a point at or slightly below the plane occupied by the upper level of the rollers 50 and 5|, and are distinguished one from the other in that the former blade has its upper verge ground to define a rather blunt wedging edge 68 whereas the other blade is channeled along the top edge and has fitted in this channel a pad 10 of elastic rubber or other cushion-like material. This wedging blade 66, or padded blade 61, as the case may be, finds its functioning complement in a related overhead striker and serves with the latter to accomplish a bisecting of the blocks fed to the platform.

The striker for the knife-edged blade is comprised simply of a cross-head 1 l, presenting at its lower end a rather blunt wedging edge 12, and is guided from above for reciprocatory movement in the same vertical plane occupied by its underfloor counterpart. The striker complement 13 for the padded blade 61 is made to hang as a foot attachment from the cross-head H, being detachably secured thereto by bolts 14. Considered in end elevation, this second striker is given an inverted-T shape to form outrigger arms 15 projecting laterally in opposite directions to very spasms nearly the side limits of the platform, and upon the underside of these outrigger arms there are provided marginal channels in which cushioning pads 16 and 1.! are fitted.

The guide-ways in which said cross-head receives its slide journal are provided by :a superstructure 1=8. Journal-mounted in this superstructure for pivotal movement about a transverse .horizontal axis, with its twoends exposed front and rear, is a rock-shaft 80. The end :8! of this shaft which is exposed to the front is made eccentric to .the rocker axis, :and enters a rectangular opening 82 provided :in the crosshead. Within said opening and taking a journal mounting upon the eccentric 8i, preferably by means of a ball-bearing 83, there is received a shuttle-plate 84 which has a slightly :reduced width and an appreciably reduced height by comparison with the width and height of the openin :82. .I provide this difference in height inorder that the striker plate, through the instrumentality of an adapter -85, may be given either a raised or a lowered setting in relation to the pivotal axis of the rock-shaft, the purpose whereof is to compensate the striker plate to the differ ences in thickness as between the thick .and thin blocks being treated. The same end could feasibly .be attained by increasing the depth of the foot attachment 13, but the arrangement of an adapter which can be bolted in place either above or below the shuttle-plate is deemed the more-desirable in that it permits adjustment when used in conjunction with a shimming pad 86 which is, perforce, applied either above or below the ,shuttle-plate. To increase the bearing surface subject to the-vertical thrust of the shuttle-plate the cross-head desirably provides out-jutting shoulders 19 above and below the opening 82.

To effectuate the necessary rocking of the rockshaft, the exposed rear end has secured thereon a pair of .lever arms 81 and 88, the former of which has its free end extending into th'einterstice between two endless chains 89--90whereat it is intermittently engaged and propelledin one direction through an approximate 45 arc by a chain-driven spanner 9|, and the other of which connects by .its free end with a return spring 92.

To drive the two conveyor chains and 24, and the lever activating chains 8'990,, in. their necessary timed relation, successive speed-reduction drives transfer the power of an electricmotor 93 .first to a pulley wheel :94 and therefrom through .achain 95 to a sprocket-wheel :96 mounted on the shaft 21 which carries thehead sprocket wheels '25 .for the high-speed conveyor chains. Also .on this shaft is an outlying sprocket wheel 9-1 from which a chain 98 carries the drive at a reduced speed to shaft 99 for the head sprocket wheel 2| of the low-speed conveyor rc'hain 120. The lever-activating chains are made toga length the same as the high-speed conveyor chains-and receive a direct drive through the instrumentality of placing the head sprocket wheels of atherformer said chains on the same shaft which .is common to the tail sprocket wheels of the platter nsa'id chains.

The operation can be described as "follows: Assuming that the block to be bisected is .the thick block, designated by I00, portrayed in Fig. 10, the adapter 85 is fixedly applied above :the shuttle-plate 84 as shown in Figs. 3, 8, and 9 and the two abrasive discs 36 and 3'! are raised and lowered, respectively, in the degree necessary to clear the trail path of the blocks. The'machine is then energized andsuccessive blocks placed upon the low-speed conveyor chain. These blocks advance in turn along the length of the two conveyors and successively come torest upon the platform, whereat the timed descent of the striker-slightly depresses the floor-forming rollers 50 and 5! and the blunt wedges then simultaneously ibear top and bottom upon the block. As the compressive pressure takes effect, with both wedges first striking a line on the substantial major axis of the block and then developing their wedging action, the block splits and creates by the break .a facing surface l0l upon each of the two halves 102 and 103 which is quite rough and irregular and yet has few if any major projections. The effect, particularly with blocks produced from an aggregate containing pumice, is almost indistinguishable from a hand-hewn building stone. The knives actually need penetrate the opposite faces of the block to only a minor extent, and the entire operation of splitting is completed in the space of time necessary for a following block to be projected onto the platform, said following block pushing the two halves of the split block forwardly onto a receiving .table' I04 from where the same are removed either automatically or by hand.

Where .it is desired to produce the thin Roman brick. the abrasive disc 32 is lowered and the abrasive disc 33 raised to occupy positions as shown .inFig. 6', and namely such as to protrude in each instance somewhat into the travel path of the thin blocks. The operator replaces the stationary blade 66 with the stationary blade 61, lowers the cross-head H by relocating the adapter .above the shuttle-plate 8,4, and attaches the foot-piece 13 to the bottom end of the cross-head. Upon energizing the machine, the procedure, as before, is to successively feed the -pre casjt thin blocks to the head end of the low-speed conveyor. Shallow trench-like scorings I05 and I06 (Fig. 12) are produced along the top and bottom faces of the blocks as they traverse the abrasive discs. Reaching the high-speed conveyor, each successive scored block, designated .by H0, is projected onto the platform and there momentarily-comes to rest in the same manner as was accomplished with the described thick blocks. As the lowering cross-head then presses the foot-piece against such block, the action which takes place is to first slightly depress the block onto the centrally placed subjacent pad and, using this pad as a fulcrum, thereupon breaks the block by the head pressure of the outrigger pads, much in the same manner as a stick is .snapped by the act of bending the same over the knee as a center fulcrum. There .is created, by the snapping action, a rough facing surface Hilupon each of the produced half-blocks or bricks I08 and I99. In producing :these Roman bricks it is preforce possible to :cast the blocks with the score lines therein, thuseliminating the need for the abrasive discs. However, the cast .scoring lack the sharp lip delineation of the abrasive-cut blocks, a feature which is considered to lend added attractiveness tothe Roman type brick,1and it seems, moreover, that a fresh-cut scorenline makes the block moreesusceptible to the snapping flexure of the applied pressures.

It is thought that the invention, its operation, andsadvantages will have been clearly understood from the -foregoing description of my illustrated preferred embodiment. It will be understood that structural changes within the scope of the teachings may be resorted to without departing from the invention and I accordingly intend that no limitations be implied and that the hereto annexed claims he read with the broadest interpretation to which the employed language fairly admits.

What I claim, is:

1. In a machine for bisecting blocks of concrete in an uncured green state, a platform adapted to give yielding support to the block and comprised of two longitudinally extending series of rollers spring-suspended to admit of being depressed downwardly and disposed one at one side and the other at the other side of the longitudinal median line of the platform, plates spring-urged inwardly within prescribed limits predetermined by the width of the blocks and constituting confining side walls for the platform, a conveyor for the blocks having flights thereon which act to feed successive blocks and push the same onto the platform, the occurrance of said flights being such that the blocks carried by the conveyor will be rather widely separated thereon and thus permit each successively delivered block to come to a momentary rest upon the platform, a stationary blade having its functioning edge positioned on the longitudinal vertical center line of the platform and spaced below the underside of a block resting upon the platform and caused by depression of the supported block to be brought from a normal inactive position into bearing engagement against the underside of the block, an overhead striker complementary to said stationary blade and mounted for reciprocatory vertical movement from an inactive elevated position into an active lowered position whereat the same engages the upper face of a block supported upon the platform and forces the same downwardly hard against the stationary blade, and means driven in timed relation to the con veyor for causing the striker to move from its inactive position into and out of active position during the momentary interval when each of the successive blocks comes to rest upon the platform.

2. Structure according to claim 1 in which the striker lies in the same plane occupied by the stationary blade, both the striker and the blade presenting a working face ground to the shape of a blunt wedge.

3. Structure according to claim 1 in which the striker is so formed as to substantially straddle the longitudinal median line of the supported block and depress the same by pressure exerted along lines parallel to and at opposite side of said median line.

4. Structure according to claim 3 in which the surfaces of both the blade and the striker which bear against the block are cushioned.

5. In a machine for bisecting blocks of concrete in an uncured green state, in combination: a platform comprised of two longitudinally extending series of rollers disposed one at one side and one at the other side of the longitudinal median line of the platform, plates spring-urged inwardly within prescribed limits predetermined by one width of the blocks and constituting confining side walls for the platform, a conveyor for the blocks having block-engaging flights thereon so placed that the blocks carried by the conveyor will be rather widely spaced thereon and thus permit the blocks delivered to the platform to stay momentarily at rest before a following block is delivered to the platform means disposed above and below the platform and mounted for relative cyclic reciprocatory vertical movement toward and from one another from normal positions inactive to the supported block into active positions whereat the same exert 0pposing line pressures in a common vertical plane upon opposite faces of the block occupying the platform, and means driven in timed unison with the conveyor for effecting said cyclic movement of the pressure-exerting means during the momentary interval when the blocks come to rest upon the platform.

6. In a machine for bisecting blocks of concrete in an uncured green state, in combination: a platform comprised of two longitudinally extending series of free-running rollers spring-suspended to admit of being depressed downwardly and disposed one at one side and the other at the other side of the longitudinal median line of the platform, plates spring-urged inwardly within prescribed limits predetermined by the width of the blocks and constituting confining side walls for the platform, a continuously driven endless conveyor for feeding the blocks to the platform and acting to bring the same successively to a momentary stop upon the platform, a stationary blade rigidly supported below the platform to occupy a vertical plane coinciding with the longitudinal vertical center of the platform and caused by depression of a platform-supported block to be brought from a normal recessed position into bearing engagement against the underside of the block, an overhead striker complementary to said stationary blade and mounted for reciprocatory vertical movement from a normal inactive elevated position into and out of a lowered active position whereat the same depresses the block hard against the blade and by the opposition thus encountered causes cracking pressure to be exerted upon top and bottom faces of the block, and means driven in timed unison with the conveyor for causing the striker to move from its inactive elevated position into and out of said active position during the momentary interval when the blocks come to rest upon the platform.

7. In a machine for bisecting blocks of concrete in an uncured green state, in combination: a platform comprised of two longitudinally extending series of rollers spring-suspended to admit of being depressed downwardly and disposed one at one side and the other at the other side of the longitudinal median line of the Platform, plates spring-urged inwardly within prescribed limits predetermined by the width of the blocks and constituting confining side walls for the platform, the admission ends of said plates being curved outwardly to form a flared lead-in throat giving access for blocks fed to the platform, a continuously driven endless conveyor for feeding the blocks to the platform and acting to bring the same successively to a momentary stop upon the platform, a stationary blade rigidly supported below the platform to occupy a vertical plane coinciding with the longitudinal vertical center of the platform and caused by depression of a platform-supported block to be brought from a normal recessed position into bearing engagement against the underside of the block, an overhead striker complementary to said stationary blade and mounted for reciprocatory vertical movement from a normal inactive elevated position into and out of a lowered active position whereat the same depresses the block hard against the blade and by the opposition thus encountered causes cracking pressure to be exerted upon top I and bottom faces of the block, and means driven in timed unison with the conveyor for causing the striker to move from its inactive elevated position into and out of said active position during the momentary interval when. the blocks come to rest upon the platform.

8. In a machine for bisecting blocks of concrete in an uncured greenv state, in combination: a platform comprised of two longitudinally extending series of free-running rollers spring-sus pended to admit of being depressed downwardly and disposed one at one side and the other at the other side of the longitudinalv median line of the platform, an endless conveyor for feeding the blocks to the platform and acting to bring the same successively to a momentary stop upon the platform, a stationary blade rigidly supported below the platform to occupy a vertical plane coinciding with the longitudinal vertical center of the platform and caused by depression of a platform-supported block to be brought from a normal recessed position into bearing engagement against the underside of the block, an overhead striker complementary to said stationary blade and mounted for reciprocatory vertical movement from a normal inactive elevated position into and out of a lowered active position whereat the same depresses the block hard against the blade and by the opposition thus encountered causes cracking pressure to be exerted upon top and bottom faces of the block, and means driven in timed unison with the conveyor for causing the striker to move from its inactive elevated position into and out of said active position during the momentary-interval when the blocks come to rest upon the platform.

9. The machine of claim 1 in which the striker is carried by a cross-head working in vertical slide-ways, said cross-head having a rectangular opening therein, and wherein the cross-head is driven by an eccentric acting upon a shuttleplate received in said opening, means being provided for adjusting the cross-head vertically in relation to the rotary axis of the eccentric in order to raise or lower the striker in adapting the' same to thick and thin blocks.

10. In a machine for bisecting blocks of concrete in an uncured green state, in combination: a platform comprised of two floor-forming sections each spring-suspended to admit of being depressed and disposed one at one side and the other at the other side of the longitudinal median line of the platform, a conveyor acting to deliver successive blocks to the platform and bring the delivered blocks to a momentary stop upon the platform, a stationary blade below the platform located on the longitudinal vertical center thereof and caused by depression of the supported block to be brought from a normal recessed position into bearing engagement against the underside of the block, an overhead striker complementary to said stationary blade and mounted for reciprocatory vertical movement from an inactive elevated position into an active lowered position whereat the same engages the upper face of a block supported upon the platform and forces the same downwardly hard against the stationary blade, and means for operating the striker from its inactive position into and out of active position during the momentary interval when a block comes to rest upon the platform.

11. In a machine for bisecting blocks of concrete in an uncured green state, in combination: a platform comprised of two floor-forming sections each spring-suspended to admit of being depressed and disposed one at one side and the other at the other side of the longitudinal median line of the platform, a pair of continuously driven and endless conveyors having blockengaging flights thereon and working in concert to give an initial low and following high speed, comparatively speaking, to successive blocks placed thereon and acting to bring. the blocks successively to a momentary stop upon the platform, each of the successively delivered blocks acting to push a previously delivered block off the platform, power-driven abrasive discs acting upon the conveyed blocks in course of their lowspeed travel to simultaneously groove the upper and lower faces thereof on lines coinciding with the longitudinal vertical center of the blocks, and pressure means operative upon said grooved blocks during the momentary interval when the blocks come to rest upon the platform for bisecting the blocks, the bisection being accomplished by subjecting the block to forces in opposition one exerted upwardly on the line of the bottom groove and the other exerted downwardly on lines removed laterally to opposite sides of the top groove.

12. The machine of claim 11 in which the pressures are applied through cushioned pads.

13. In a machine for bisecting blocks of concrete in an uncured green state, in combination: a platform comprised of two floor-forming sec tions each comprised of a series of free-running rollers disposed one at one side and the other at the other side of the longitudinal. median line of the platform, an endless continuously driven conveyor having rather widely separated blockengaging flights thereon and disposed in such relation to the platform as to deliver the leading end of a conveyed block onto the admission end of the platform and by continued exertion of pressure from the related flight upon the following end of the block to then positively advance said block until the latter reaches a given position localized with respect to bisecting means associated with the platform, said advancing block acting to push a previously localized block off the platform, and. bisecting means acting in opposition upon the top and bottom faces of the localized blocks during the momentary interval when the blocks come to rest upon the platform for developing a bisecting split by first striking a surface line along the longitudinal median center on both top and bottom faces of the block and then exerting wedging pressures on the lines so struck.

14. In a machine for bisecting blocks of concrete in an uncured green state, in combination with a platform adapted to give yielding support to the block and comprised of two floor-forming sections each spring-suspended to admit of being depressed and disposed in transversely spaced relation one at one side and the other at the other side of the longitudinal median line of the platform, means comprised of a movable and a stationary blade each normally out of engagement with the supported block and occupying positions, the former above and the latter below the block in a common plane coinciding with the longitudinal vertical center line of the supported block, and means acting upon said movable blade to force the same downwardly hard upon the block to overpower the yielding resistance imposed by the platform and establish compressive line pressures from the two blades upon opposite faces of the block, the downward movement of said movable blade beyond its point of contact with the block being of minor magnitude by comparison with the thickness of the block.

15. In a machine for bisecting blocks of concrete in an uncured green state, in combination with a platform adapted to give yielding support to the block and comprised of two floor-forming sections each spring-suspended to admit of being depressed and disposed in traversely spaced relation one at one side and the other at the other side of the longitudinal median line of the platform, opposed means above and below the supported block arranged for relative and comparatively minor vertical movement into and out of positions whereat the same exert line pressures upon top and bottom faces of th block, the lower of said means being disposed to occupy a plane coinciding with the longitudinal vertical center line of the block.

16. In a machine for bisecting blocks of concrete in an uncured green state, in combination with a platform the floor of which is composed of two longitudinally extending series of rollers occupying transversely spaced positions one at one side and the other at the other side of a longitudinal center line, and having retaining walls along the sides, springs acting to yieldingly urge the floor upwardly and the walls inwardly within fixed limits, means for interruptedly feeding successive blocks onto the platform, complementary opposed blades one being vertically movable and normally occupying a position elevated above a block resting on the platform and the other being stationary and located below the platform with its functioning edge normally out of contact with a block resting upon the platform, and power means acting to force said upper blade downwardly toward the lower stationary blade so as to depress the block and the platform and responsively establish compressive block-bisecting pressure from the two blades upon the block.

17. Structure according to claim 11 having a stationary guide wall against which one side edge of the conveyed block is adapted to bear as the block traverses the grooving discs, and a complementary wall spring-urged inwardly and arranged to yielding press against the other side edge of the conveyed block for holding the latter against said guide wall.

18. In a machine for bisecting blocks of uncured green concrete, a continuously driven endless conveyor having its upper run located in an approximately horizontal plane and presenting equidistantly spaced block-engaging flights separated one from another in a degree fairly exceeding the length of the blocks, a platform extending as a substantial prolongation of said upper run beyond the tail extremity of the latter and acting to receive and momentarily immobilize blocks which are successively fed thereto by the conveyor, the delivery to the platform of each of said successively fed blocks operating to push a previously immobilized block off the platform, a striker mounted above the platform for reciprocal vertical movement from a normal elevated inactive position into and out of a depressed active position whereat the same operates to engage and bisect a block immobilized upon the platform, and means made to operate in timed concert with the conveyor for operating the striker from its active position into and out of said active position during the momentary interval when each of said successively fed blocks is immobilized upon the platform.

19. Structure according to claim 18 having means for adjusting the striker vertically so as to raise or lower the zone in which the reciprocal action takes place and thus adapting the striker to blocks of diifering thicknesses.

20.. A machine for bisecting blocks of concrete in an uncured green state and comprising, in combination with a machine frame, a block-supporting platform having a longitudinal opening in its center and guidably carried by the frame for vertical movement within prescribed limits, means exerting yielding force upon the platform to urge the same upwardly, a horizontally extending rail arranged to register with said platform opening and so carried by the frame as to occupy a position on the longitudinal center line of the opening with the upper edge positioned below the normal elevated level of the platform and exposable above the latter by the act of depressing the platform, a blade having a wedgeshaped horizontally extended lower edge disposed co-planar to the rail and guidably carried by the frame for reciprocal vertical move ment above the platform into and out of a position whereat said edge strikes the block and pushes the same downwardly hard against the rail, means for activating the blade in its said reciprocal movement, a fitting having two parallel pendant rails thereon and arranged in the bisecting of a block to be used alternatively with the wedge-shaped edge of the blade, and means for removably attaching said fitting to the blade so as to have the rails lie parallel with the wedgeshaped edge and spaced equidistantly one to one side and the other to the other side thereof with the lower edges occupying a common horizontal plane lower than the horizontal plane occupied by the wedge-shaped edge.

MILTON R. PRICE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 158,691 Dutertre Jan. 12, 1875 812,973 Barr et al Feb. 20, 1906 1,084,827 Sudre Jan. 20, 1914 1,275,459 Miller Aug. 13, 1918 1,319,190 Van Houten Oct. 21, 1919 1,873,721 Postley Aug. 23, 1932 1,919,800 Newsom July 25, 1933 1,919,801 Newsom July 25, 1933 1,932,659 Granite Oct. 31, 1933 1,976,855 McKee et a1 Oct. 16, 1934 1,995,741 Granite Mar. 26, 1935 2,058,727 Schreiber Oct. 27, 1936 2,319,154 Orlow May 11, 1943 2,452,706 White Nov. 2, 1948 2,514,352 Solomito July 4, 1950 FOREIGN PATENTS Number Country Date 18,083 Sweden Jan. 25, 1907

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