US2957222A - Apparatus for producing concrete blocks and the like - Google Patents

Description

Oct. 25, 1960 L. ZMANlA ETAL APPARATUS FOR PRODUCING CONCRETE BLOCKS AND TFE LIKE Filed Nov. 23, 1954 6 Sheets-sheaf. 1

4 7 s a 3 w. a MAM m \I myw 2 E4 0 WMC W I 6 ZN A 0 Z 9 MW 5W I. II m Y 3 B an ..w a :w 1 if h.. .lhh. 5 1 w \x m w Oct. 25, 1960 L. IZMANIA ETAL 2,957,222

APPARATUS FOR PRODUCING CONCRETE BLOCKS AND ma LIKE Filed Nov. 23, 1954 6 Sheets-Sheet 2 g/vwm F) TTORNE) Oct. 25, v1960 L. ZMANIA EI'AL 2,957,222

I APPARATUS FOR PRODUCING CONCRETE BLOCKS AND THE LIKE Filed Nov. 23, 1954 V 6 Sheets-Sheet 3 I a v s 49 5/ 5e 66 V l I I I V INVENTORS A TT'ORIVEV Oct. 25, 1960 L. ZMANIA ETAL 2,957,222

APPARATUS FOR PRODUCING CONCRETE BLOCKS AND TPE LIKE Filed Nov. 23, 1954 6 Sheets-Sheet 4 INVENTORS LEO z my/a MW C O VJEN ATTORNEY Oct. 25, 1960 L. ZMANIA arm. 2,957,222-

APPARATUS FOR PRODUCING CONCRETE BLOCKS AND THE LIKE Filed Nov. 23, 1954 e Sheets-Sheet 5 FITTOEIUEY Oct. 25, 1960 L. ZMANIA ET AL APPARATUS FOR PRODUCING CONCRETE. BLOCKS AND THE LIKE Filed NW3, 1954 OPERATOR 's V BRATOF? l CONTR L SWPL-Q MR IN HTHC 6 Sheets-Sheet 6 wean-ran (AM 331,

MBIN (0H TBCT LIMIT SWITCH B-PHR 5E LINE FFH FH REVERSIBLE Mow-ca 6O United States Patent APPARATUS FOR PRODUCING CONCRETE BLOCKS AND THE LIKE Leo Zmania, 4611 W. 87th Place, Oak Lawn, IlL, and Marvin C. Onsen, 1226 Circle Ave., Forest Park, Ill.

Filed Nov. 23, 1954, Ser. No. 470,661

'6 Claims. (CI. 25-41) This invention relates generally to block manufacturing and more particularly is concerned with improved means for manufacturing concrete building blocks which are uniform in size and density.

The necessity for height and density control in the manufacture of concrete blocks is unquestioned, since uniform blocks stack better in the yard and please the mason who wants to lay straight courses with an even mortar line. One known method of producing uniform blocks is to fill the block forming mold with an ample charge of concrete and to then vibrate the same for a period of time just sufficient to compact the concrete to a predetermined height. This method is not entirely satisfactory because the charge of concrete may be such in quantity and condition that it cannot be reduced to the predetermined height by vibration, as a consequence of which the machine must be stopped until the condition is corrected. Another known method of producing uniform blocks is to fit the block making machine with a cut-off bar operative to afford charges of concrete uniform in quantity. This latter method also is not entirely satisfactory because when the condition of the concrete in the supply hopper changes, the cut-off bar must be adjusted to correspond, and the required adjustment cannot be made until the machine is stopped.

Accordingly, a principal object of the present invention is to provide a concrete building block machine with improved height and density control means which functions automatically and without any necessity for stopping the machine.

Another object of the present invention is to provide such a device which can adjust for each block forming cycle and which is operative to reduce a concrete charge in a mold of predetermined cross sectional area to an uncompacted height dependent upon the condition of the concrete charge from which the last block was made.

Still another object of the present invention is to provide such a device which adjusts as aforementioned to effectively control the operating level of means for wiping across the top of the mold to afford an uncompacted charge of concrete the height of which bears a critical relation to the condition of the concrete charge from which the last block was made.

And a further object of the present invention is to provide a concrete building block machine which nor mally is operative to terminate the compacting operation when the concrete in the mold is finally reduced to a predetermined height, without regard to the point in the block making cycle when the concrete may be reduced to such height.

And still another object of the present invention is to provide such a device which is exceedingly simple in design and construction and which is comparatively simple and inexpensive to manufacture.

Other objects and advantages of the present invention will appear more fully hereinafter, it being understood that said invention consists substantially in the combination, construction, location and general arrangement of "ice parts, all as described in detail in the following specification, as shown in the accompanying drawings and as fully pointed out in the appended claims.

In the accompanying drawings:

Figure 1 is a perspective view looking at the front and the right side of a block forming machine embodying the present invention;

Figure 2 is a perspective view looking at the front and the right side of the machine and showing the main frame mold section and the feed box assembly, a portion of the stripper frame assembly and the control device;

Figure 3 is a vertical section taken on line 3--3 of Figure 1;

Figure 4 is an enlarged vertical section through a portion of the machine, the feed box assembly being shown in its retracted position and fully elevated;

Figure 5 is the same as Figure 4, however, the feed box assembly is shown in its forwardly extended position and only partially elevated;

Figure 6 is the same as Figure 4, however, the feed box is shown fully lowered;

Figure 7 is a vertical longitudinal section through the machine, the feed box being shown in its retracted 'position and fully lowered, and the stripper head being shown fully :lowered for stripping the mold and delivering the finished block to the pallet receiver frame assembly;

Figure 8 is an enlarged vertical section on line 8-8 of Figure 3;

Figure 9 is an elevation of the machine as viewed from the left side, just prior to descent of the stripper head;

Figure 10 is a fragmentary elevation of the machine as viewed from the left side, just prior to ascent of the stripper head; and

Figure 11 is a wiring diagram schematically showing the main control electric circuit for controlling the action of the height and density control device of the present invention.

It will be understood that the present invention comprises means for automatically producing concrete building blocks of predeterminedly established uniform height and density without necessitating any substantial interruption in the operation of the block-making machine. Inasmuch as the block-making machine in which is incorporated the present invention is of conventional construction and well known in the art, only such parts of the machine as are necessary for a clear understanding of the present invention have been shown in the drawings and will be described in the following specification.

Now referring to the drawings, the machine embodying the present invention comprises a floor supported main frame indicated generally by the numeral 10. The main frame 10 includes a mold section 11 located a suitable distance above the floor. Operatively mounted upon the main frame 10 at an elevation just above that of the mold 11 is a feed box assembly indicated generally by the numeral 12. Directly over the mold 11 is a stripper head assembly indicated generally by the numeral 13, and directly under the mold 11 is a pallet receiver assembly indicated generally by the numeral 14.

Suitable power transmitting means is provided for actuating the feeder box assembly 12, stripper head assembly 13 and pallet receiver assembly 14 in a predetermined timed relation. The aforementioned means includes an electric motor 15 located on the right side and to the rear of the machine. The motor 15 is provided with a belt 15 through which it drives a jack shaft 16, and the latter is provided with a second belt 16 located laterally outwardly of the belt 15*, through which it drives a pulley shaft 17. On the left side of the machine, the pulley shaft 17 is provided with a spur pinion 17 which drives a spur gear 17 and a cam shaft 18 upon which the spur gear 17 is mounted.

., V l a 3" In addition to mounting the spur gear 17 the cam shaft 18 mounts a feed box control cam 18 located laterally outwardly of the spur gear 17*. On the right side ofjhe machine, the'cam shaft 18 mounts a pair of stripper head; control { cams 19 and 19 and a pallet receiver control cam 20 located laterally outwardly of the cams 19 and 19 The feed box control cam 18 engages a cam follower arm 20* which is mounted upon a feeder arm shaft 21. In addition to mounting the cam follower arm 20*, the feeder arm shaft 21 mounts a pair of feeder arms 21*---21 located respectively on opposite sides of the machine and operatively connected to the feed box assembly 12 through the medium of a pair of rods 22-22. For maintaining the cam follower arm 20 engaged with the feed box control. cam 18 a suitable tension spring assembly 23 is operatively interposed between the feeder arm shaft 21'and a beam 24 which is anchored to the main frame 10 of the machine. The stripper head control earns 19 and 19 respectively engage a pair of cam follower arms 25 and 25 which are mounted upon a stripper head shaft 26. 'In addition to mounting the cam follower arms 25 and 25 the stripper head shaft 26 mounts a pair of rock arms 27-27 located respectively on opposite sides of the machine and operatively connected .tothe stripper head assembly 13 'through the medium of a pair of links 28-28. The pallet receiver control eam'zo engages a cam follower arm 28* which is mounted upon a pallet receiver shaft 29. In addition to mounting the cam follower arm 128*, the pallet receiver shaft 29 mounts a pair of rock arms 30-30 located respectively on opposite sides of the machine and operatively connected to the pallet receiver assembly 14 through the medium of compression spring link assemblies 31-31.

Referring particularly to Figure 3, in the operation of the machine, a feed box 31 which is included in the feed box assembly 12, is charged with wet concrete from an overhead supply hopper 32. The feed box 31 then moves to the forwardly extended position shown in Figure to locate the charge of wet concrete over the mold The charge immediately drops into the mold 11, and then the feed box 31 retracts to its original position under the hopper 32. For compacting the fresh concrete with which the mold 11 is charged, vibrator assembiles indicated generally by the numerals 33-33 are provided. The vibrators 33-33 are connected in electric circuit with a vibrator cam switch 33* which is operatedby a' vibrator cam 33 mounted on the cam shaft 18 and located laterally outwardly of the feed box control cam 18*. The vibrator cam 33*" is of such shape and is so mounted that thes'witch 33 is depressed for a predetermined portion of the block making cycle of the machine, commencing whenthe feed box 31 begins to move forwardly to deliver its charge. to' the mold 11-, vibration of the latter being effected thereby for a corresponding portion of the aforementioned cycle. After the feed box 31 has delivered its charge and returned to its original position under the hopper 32, a stripper head 34, which 'is included in the stripper head assembly 13, descends to finally compact the block to its required height and to thereafter stripthe completed block 34 from the mold 11. The block 34 and a supporting pallet 35, which is included in the pallet receiver assembly 14, are then lowered to the position shown in Figure 7, from which position the completed block 34* is free to be removed from the machine either by hand orany suitable power-operated means. During the actual stripping op eration, the stripper head 34 and the pallet 35 move downwardly'together normally 'at a distance apart corresponding to the desired height of'the block 34*. This distance 'is controlled by a pairof. adjustable spacer members carried by thestripper head assembly for movement therewith and a pair of spacer members which register respectively with the aforementioned adjustable spacer members and which are carried by the palle recei e a se r 4 movement therewith, there being one pair of registering spacer members on each sideof the machine. In the block making machine of the character just described, when the concrete mix is too fluid for formation of a block of the required density, the tendency is for the block to be compacted to its required height before the vibration period terminates, in consequence of which the vibration which occurs subsequent to compacting of the block 34 to its required height further compacts the concrete, thus causing the formation of a block which is of a height less than that desired. .On the other hand, when the concrete mix is too firm for formation of a block'of the required density, the tendencyis for the vibration period to terminate before the block is compacted to the de sired height, which, of course, is undesirable. In addition, the pallet 35 may begin to move downwardly before the stripper head 34 has sufficient time to compact the concrete in the mold 11 to the desired height, inconsequence of which there may be formed a block which is of a height greater than that desired. The construction and operation of the machine as so far described is old and well known in the art, and, therefore, any further general description is deemed to be unnecessary for a full understanding of the present invention.

'The feed box 31 conventionally includes a pair of transversely spaced side plates 36-36 the corresponding rear end portions of which are joined by a bar '37 and corresponding intermediate portions of which are joined by a bar 38 and additionally by a plate 39 positioned as shown. Corresponding front end portions of the side plates 36-36 respectively mount angle brackets 42-42 and rollers 43-43. The corresponding front terminal portions of the side plates 36-36 are joined by a rigid cut-off bar 44 which is removably secured in any suitable manner against displacement and for movement with the feed box 31*. The feed box assembly 12, including the feed box 31 just described, is normally mounted in the conventional machine on the main frame 10 for simple rectilinear movement of the feed box 31 fore and aft of the machine. In order to adapt the machine to and for the purposes of the present invention, the feed box assembly 12 is mounted on the main frame 10. in a different manner now to be described.

For operatively supporting the front end of the feed box 31*, the feed box assembly 12 includes a track subassembly 45 having laterally spaced parallel tracks 46-46 located respectively on opposite sides of the feed box 31* and in underlying relation to the rollers 43-43. The front end portions of the tracks 46-46 are fitted respectively with a pair of pins 47-47 through the medium of which the fore ends of the tracks are supported respectively by a pair of levers 48-48 which are to be described hereinafter. Corresponding rear end portions of the tracks 46-46 are secured respectively to opposite side front end portions of an apron plate 49, as by spaces 50-50 and bolts 51. The opposite side rear end portions of the apron plate 49 are fitted respectively with a pair of brackets 52-52 which are respectively pivoted on a pair of studs 52 -52 The latter are coaxially related and project inwardly respectively from opposite sides of the main frame 10 and respectively through the brackets 52-52, the subassembly 45 being thereby mounted on the main frame 10 for pivotal movement about a transversely extending horizontal axis.

For operatively supporting the rear end of the feed box 31*, the feed 'box 31 is provided with a longitudinally extending runner plate 52 the front end of which is secured to the underside of the plate 39 and the rear end of which is proximate thebar 37. Underlying the runner plate 52 is a roller 52 carried by a cross beam 52 anchored to the main frame 10. The feed box 31 isthus adapted to reciprocate'fore and aft over the roller 52 and additionally to rock thereon when the front end of-the feeder box 31 is raised or lowered in the manner to be described hereinafter.

The height and density control device of the present invention comprises a rock shaft 53 which is journaled in corresponding opposite side portions of the main frame 10, as at 54-54, and which is provided with a pair of rock arms 55-55 pivotally connected respectively to the lower ends of a pair of link assemblies 56-56. The upper ends of the link assemblies 56-56 are pivotally connected respectively to corresponding ends of the pair of levers 48-48. The levers 48-48 extend forwardly from the link assemblies 56-56 respectively in superposed spaced relation to the rock arms 55-55. The front end portions of the levers are suitably shaped to provide elements 57-57 respectively for seating the pins 47-47'. A pair of brackets 58-58 project inwardly from corresponding opposite side portions of the main frame and are disposed respectively in underlying relation to corresponding intermediate portions of the levers 48-48 for rocking movement of the levers 48-48 thereon in response to oscillating movement of the shaft 53. For actuating the latter, the same is coupled to a speed reduction unit 59 which derives power from a reversible three phase electric motor 60 through a belt drive 61. The action of the height and density control device of the present invention is determined by rotation of the reversible motor 60, and the motor 60, in turn, is controlled by apparatus connected in a main control electric circuit hereinafter described.

As set forth hereinbefore, the feed box 31 retracts to its original position under the hopper 32 after dropping a charge of fresh concrete into the mold 11. As the feed box retracts, the cut-off bar 44 wipes across the top of the fresh concrete and removes any excess material which extends above the lower edge of the cutoff bar 44. Then the stripper head 34 descends and normally rests upon the concrete, floating free of the stripper head control cam 19- for the short period of time (just prior to commencement of the actual stripping operation) during which the block 34 is compacted to the required height. When the concrete mix is properly proportioned for the production of blocks of the desired height and density the spacer members carried respectively by the stripper head and pallet receiver assemblies make contact at a predetermined point during the block making cycle. The time when the spacer members make contact may be advanced or delayed, depending upon the condition of the concrete mix. The concrete mix may be too fluid or soft, in which event it may not support the stripper head 34 at all, or, if it does, the period of time during which the stripper head 34 rests on and is supported by the concrete is cut short, in consequence of which the time when the spacer members make contact is advanced. On the other hand, the concrete mix may be too stiff or firm, in which event the aforementioned period of time is extended, in consequence of which the time when the spacer members make contact is delayed.

When the concrete mix is too fluid or soft and the spacer members make contact prematurely, as aforementioned, a block of the desired height is formed, provided there was enough concrete to adequately fill the mold 11, but the block is of lesser density then that desired, in consequence of which adjustment of the machine is required. The necessary adjustment is effected automatically by the height and density control mechanism of the present invention as follows. The rotation of the electric motor 60 is translated into counter clockwise movement of the rock shaft 53 and of the rock arms 55-55 (as viewed from the left side of the machine), in consequence of which the link assemblies 56-56 are drawn downwardly and the levers 48-48 are rocked respectively on the brackets 58-58 in a counter clockwise direction so as to raise the front ends of the tracks 46-46 through the medium of the pins 47-47 (see Figure 6 and compare with Figures 4 and 5). Since the front end of the feed box 31*- is carried by the tracks 46-46, it is raised correspondingly, in consequence of which the cut-off bar 44 is adjusted for operation at a higher level.

When the concrete mix is too stifi or firm and the spacer members make delayed contact, as aforementioned, a block of greater density and/or height is formed, in consequence of which adjustment of the machine is required. The necessary adjustment is effected automatically by the height and-density control mechanism of the present invention as follows. The rotation of the electric motor 60 is translated into clockwise movement of the rock shaft 53 and of the rock arms 55-55 (as viewed from the left side of the machine) as a consequence of which the link assemblies 56-56 shift upwardly and levers 48-48 are rocked respectively on the brackets 58-58 in a clockwise direction so as to lower the fore ends of the tracks 46-46 through the medium of the pins 47-47 (see Figure 4 and compare with Figures 5 and 6). Since the front end of the feed box 31 is carried by the tracks 46-46, it is lowered correspondingly, in consequence of which the cut-off bar 44 is adjusted for operation at a lower level.

The height and density control device of the present invention adjusts not more than once during each block making cycle. Each adjustment raises or lowers the cutoff bar a uniform selected distance, in consequence of which it may require a number of successive adjustments to raise or lower the cut-off bar to the best operating position.

Referring particularly to Figure 11, the main control circuit includes the vibrator cam switch 33 The latter is operated by the vibrator cam 33*, which is operatively connected to the electric motor 15 for rotation thereby at a rate which is uniform. The electric motor 15 is conventionally connected in an electric circuit which is not described or shown herein. In addition to the vibrator cam switch 33 the main control circuit includes a pair of main contacts 65 and 66. The main contact 65 is the spacer member on the left side of the machine, mentioned hereinbefore, carried by the stripper head assembly 13, and the main contact 66 is a cap mounted upon and suitably insulated from the underlying registering spacer member carried by the pallet receiver assembly 14.

The main control circuit also includes a mercury switch which has a left hand set and a right hand set of contaots, and which is arranged for operation when it is suitably shorted. In addition to the mercury switch, the main control circuit includes an operators vibrator control switch through the medium of which operation of the vibrators 33-33 may be terminated and through which automatic or manual operation of the vibrators 33-33 may be selectively effected.

The relay designated R1 is an automatic circuit control relay which controls the vibrators 33-33. Whenever the relay R1 is energized, the vibrators operate; whenever the relay R1 is dc-energized, the vibrators are disabled. The timer designated Tl. is a lowering circuit timer which is set up when a safety circuit relay designated R2 is energized. In addition to setting up the timer T1, the relay R2, at the same time, operates the mercury switch. The timer designated T2 is a naising circuit timer, and the timer designated T3 is operative to prevent excessively sensitive operation of the timer T2. The relay designated R3 is a raise relay which, when energized, closes a switch S3 in the 3-phase power line for reversible motor 69, in consequence of which the motor 60 rotates in a direction which effects raising of the cut-off bar 44 in the manner already described. The relay designated, R4- is a lowering relay which, when energized, closes a switch S4 in the 3-phase power line for reversible motor- 64), in consequence of which the motor 60 rotates in a direction which effects lowering of the cut-off bar 44 in" the manner already described. The relay designated R5 is operative to control the point in the block making cycle blocks to be made.

7 at which the raising operation begins. .For limiting lowering of the cut-01f bar 44, a limit switch 62 is furnished, and ,for limiting elevation of the cut-01f bar 44, a limit switch 63 is furnished. The limit switches 62 and 63 are suitably disposed for coaction with a switch actuating arm 64 which is carried by the link assembly 56 lo'cated 'on the left side of the machine.

; During the initial portion of each block making cycle, i.e., while the vibrator cam switch 33 is engaged with the leading portion of the raised part of the vibrator cam 33', and themain contacts 65 and 66 are disengaged, the vibrator cam switch 33 is in the full line depressed position shown in the wiring diagram, and the mercury switch is in its uuoperated position, wherein the left hand seto' f contacts are closed and the right hand set of contacts are open. In this condition of the main circuit, electric current is supplied to the relay R1 and the timer T3 through the operators switch and the vibrator cam switch 33 the closed. left hand, contacts of the mercury switch and the closed contacts R1 of the relay R1. Since relay R1 is energized, the vibrators operate. In addition, the normally open co'ntacts R1 and R1-1 of the relay R1 are closed, while the normally closed contacts R1-2 of'the relay R1 are open. Since the timer T3 is energized, the normally closed time closed contacts T3 of the timer T3 are open. The vibrator cam switch 33 cuts off the supply of electric current to the relay R2, in consequence of which the normally open contacts R2 and R2-1 of relay R2 are open. Since the contacts R2 are open, the supply of current to the timer T1 is cut off, as a result of which the normally open timed open contacts .T1 of the timer T1 are open. The supply of current to the relay R4 is cut 01f by the open contacts RI-Z of the relay R1 and T1 of the timer T1. The open right hand setof contacts of the mercury switch and the open contacts T3 of the timer T3 cut 011 the supply of electric current to the relay R5 and the timer T2, in consequence of which the normally closed contacts R5 of therelay R5 are closed, and the normally open timed open contacts T2 of the timer T2 are open, cutting off the supply of electric current to the relay R3. Since the electric current is cut off from both the raise relay R3 and the lowering relay R4, neither the switch S3 nor the switch S4is operated, in consequence of which the reversible motor 60 remains motionless.

In initially arrangingthe machine for operation, the spacer members are adjusted so that when they engage, the stripper head 34 and the pallet 35 are a clear distance apart corresponding to the desired height of the In addition, the vibrator cam 33 (a compound adjustable member) is adjusted so that when the concrete mix is properly proportioned for the formation of a block of the desired height and density,

the vibrator cam switch 33* is depressed when the block forming cycle begins and is released as the main contacts 65 and 66 engage.

Again referring particularly to Figure 11, when the machine is initially arranged as aforementioned and a properly proportioned concrete mix is utilized, upon simultaneous release of the vibrator cam switch 33 and engagement of the main contacts 65 and 66, the vibrator cam switch 33 assumes the dotted line released position shown in the wiring diagram, and the mercury switch is operated so that the left hand set of contacts open and the right hand contacts close. In this condition of the main control circuit, the electric current is cut off from the relay R1 and the timer T3 by the vibnato'r cam switch 33 the open left hand set of contacts of the mercury switch and the open contacts R1 of the relay R1. Since the relay R1 is de-energized, the vibrators cease to operate. In addition, the normally open contacts.R1 and R11 of the relay R1 open, while the normally closed contacts R1-2 of the relay R1 close. The normally closed time clo'sed contacts T3 of the timer "T3 remain open. The supply of electric current tothe relay R2 is cut ofi by the open contacts R1-1- of the relay R1, in consequence of which the normally open contacts R2 of the relay R2 remain open, cutting off the supply of electric current to the timer T1. In turn, thenormally open timed open contacts T1 of the timer T1 remain open, cutting ofi the supply of electric current to the relay R4. The vibrator cam switch 3-3 and the open contacts T3 of the timer T3 and R1 of the relay R1cut ofi the supply of electric current to the relay R5 and the timer T2, in consequence of which the normally closed contacts R5 or" the relay R5 remain closed, and the no'rmally open timed open contacts T2 of the timer T2 remain open, cutting oil. the supply of electric current to the relay R3. Since the electric current remains cut oil. from both the raise relay R3 and the lowering relay R4, neither the switch S3 nor the switch S4 is operated, in consequence of which the reversible motor 61 still remains motionless.

When the concrete mix is too fluid or soft and the main contacts 65 and 66 make'contact prematurely, i.e., before the vibrator camswitch 33 is released by the vibrator cam 33", the vibrator cam switch remains in the full line depressed position shown in'the wiring diagram, and the mercury switch is operated so that the left hand set of contacts open and the right hand set of cont-acts close. In this condition of the main control circuit the electric current is cut ofi from the relay R1 and the timer T3 by the open left hand set of contacts of the mercury switch and the open contacts R1 of the relay R1. Since the relay R1 is tie-energized, the vibrators cease to operate. In addition, the normally open contacts R1 and R1.-1 of the relay R1 open, while the normally closed contacts R1-2 of the relay R1 close. The normally closed time closed contacts T3 of the timer T3 remain open. The supply of electric current to the relay R2 is cut ofi by the vibrator cam switch 33 and the open contacts Rl-l of the relay R1, in consequence of which the normally open contacts R2 of the relay R2 remain open. The supply'of electric current to the timer T1 is cut oiT by the vibrator cam switch 33 and the open contacts R2 of the relay R2. The normally open til-ned open contacts T1 of the timer T1 remain open, cutting off the supply of current to the relay R4. The open contacts T3 of the timer T3 cut off the supply of electric current to the relay R5 and the timer T2, in consequence of which the normally closed contacts R5 remain closed, and the normally open timed open contacts T2 of the timer T2 remain open, cutting 011 the supply of electric current to the relay R3. Since the electric current remains cut off from both the raise relay R3 and the lowering relay R4, neither the switch S3 nor the switch S4 is operated, in consequence of which the reversible motor 60 continues motionless.

After a predetermined time interval, the normally closed time closed contacts T3 of the timer T3 close, whereupon electric current is supplied to the relay R5 and the timer T2 through the operators switch and the vibrator cam switch 33 the closed left hand set of contacts of the mercury switch and the closed contacts T3 of the timer T3. Since the timer T2 is energized, the normally open timed open contacts T2 of the timer T2 close, and since the relay R5 is energized, the normally closed contacts R5 of the relay R5 open, cutting off the supply of current to the relay R3.

When the vibrator cam switch 33 is finally released by the vibrator cam 33', the electric current to the relay R5 and the timer T2 is cut off by the vibrator cam switch 33 and the open contacts R1 of the relay R1, the relay R5 and timer T2 being de-energized simultaneously. Since the relay R5 is de-energized the normally closed contacts R5 of the relay R5 close. The normally open timed open contacts T2 of the timer T2 remain closed, whereupon electric current is supplied to the raise relay R3 is closed and the reversible motor 60 is supplied with electric current for rotation thereof in a direction to raise the cut-off bar 44. After a predetermined interval, the contacts T2 of the timer T2 open and the supply of electric current to the raise relay R3 is cut ofi, whereupon the switch S3 opens and the supply of electric current to the reversible motor 60 is cut oflf.

When the concrete mix is too stiff or firm and the vibrator cam switch 33- is released while the main contacts 65 and 66 are still separated, the vibrator cam switch 33 assumes the dotted line released position shown inthe wiring diagram, and the mercury switch initially remains in the unoperated position, wherein the left hand set of contacts are closed and the right hand set of contacts are open. In this condition of the main control circuit, electric current is supplied to the relay R1 and the timer T3 through the closed contacts R1 of the relay R1 and the closed left hand set of contacts of the mercury switch. Since the relay R1 is energized, the vibrators continue to operate. In addition, the normally open contacts R1-1 of the relay R1 remain closed and the normally closed contacts R1-2 of the relay R1 remain open. The normally closed time closed contacts T3 of the timer T3 remain open. The relay R2 is supplied with electric current through the vibrator camswitch and the closed contacts R1-1 of the relay R1, in consequence of which the normally open contacts R2 of the relay R2 close, whereupon electric current is supplied to the timer T1 through the vibrator switch and the closed contacts R2. Since the timer T1 is energized, the normally open timed open contacts T1 of the timer T1 close. The supply of electric current to relay R5 and timer T2 remains cut oii by the open left hand contacts of the mercury switch and the open contacts T3 of the timer T3, in consequence of which the normally closed contacts R5 of the relay R5 remain closed, and the normally open timed open contacts T2 of the timer T2 remain open. The supply of electric current to the relays R3 and R4 is cut ofi respectively by the open contacts T2 of the timer T2 and R1-2 of the relay R1.

When the relay R2 is energized as aforementioned, in addition to the normally open contacts R2 of the relay R2 being closed, the normally open contacts R21 of the relay R2 are closed, in consequence of which the mercury switch is operated, the left hand contacts being opened.

and the right hand contacts being closed. It will be understood that there is a slight time delay between release of the vibrator cam switch 33 and operation of the mercury switch In this condition of the main control circuit, the supp-1y of electric current is cut off from the relay R1 and the timer T3 by the vibrator cam switch 33 and the open left hand contacts of the mercury switch. Since the relay R1 is de-energized, the vibrators cease to operate. In addition, the normally open contacts R1 and R1-1 of the relay R1 open, and the normally closed contacts R12 of the relay R1 close. The normally closed time closed contacts T3 of the timer T3 remain open. The supply of electric current to the relay R5 and the timer T2 is cut off by the open contacts R1 of the relay R1 and T3 of the timer T3 and by the vibrator cam switch. The relay R5 being de-energized, the normally closed contacts R5 of the relay R5 remain closed, and the timer T2 being de-energized, the normally open timed open contacts T2 remain open, cutting ofi the supply of electric current to the relay R3. The supply of electric current is cut off from the relay R2 by the open contacts R14. Since the relay R2 is de-energized, the contacts R2 of the relay R2 open, cutting ofi the supply of electric current to timer T1. The normally open timed open contacts T1 of the timer T1 remain closed, whereupon elec tric current is supplied to the lowering relay R4 through the closed contacts R12 of the relay R1 and T1 of the timer T1, in consequence of which the relay R4 operates the switch S4, closing the same to supply the reversible motor 60 with electric current for rotation thereof in a direction to lower the cut-ofi bar 44. After a predetermined interval, the contacts T1 of the timer T1 open and the supply of electric current to the lowering relay R4 is cut off, whereupon the switch S4 opens and the supply of electric current to the reversible motor 60 is cut oflE.

It will be understood, of course, that the present invention is susceptible of various changm and modifications which may be made from time to time without involving any departure from the general principles or real spirit thereof. For example, instead of the mold being positionally fixed and the cut-oif bar movable thereover, the cut-oif bar might be positionally fixed and the mold movable thereunder. Accordingly, it is intended to claim the same broadly, as well as specifically, as indicated in the appended claims.

What is claimed as new and useful is:

1. In a block making machine which operates automatically in repeating block making cycles having a mold, means for charging said mold with a determined volume of block molding material, and means for compacting the material in said mold to form a block and for stripping the block from said mold; the combination comprising a pair of laterally spaced parallel rails respectively disposed at opposite sides of the mold and extending fore and aft of the machine, a bottomless feed box movably along said rails and having a front wall the bottom edge portion of which is adapted to scrape the upper surface of moldable material deposited in the mold by said feed box, pivot means associated with said rails and spaced rearwardly of the mold for permitting tilting movement of the rails relatively to the horizontal and corresponding variation in spacing of the front wall of the feed box above the mold, means operatively connected to the rails proximate their fore ends to tilt the rails about said pivot and thereby vary the inclination of said feed box in accordance with the tilt of said rails, said rail tilting members extending upwardly from below the rails toward said fore ends of the rails, and means underlying said rails for supporting said rail-tilting members.

2. In a block making machine which operates automatically in repeating block making cycles having a mold, means for charging said mold with a determined volume of block molding material, and means for compacting the material in said mold to form a block and for stripping the block from said mold; the combination comprising a pair of laterally spaced parallel rails respectively disposed at opposite sides of the mold and extending fore and aft of the machine, a bottomless feed box movable along said rails and having a front wall the botom edge of which is adapted to scrape the upper surface of moldable material deposited in the mold by said feed box, pivot means associated with said rails and spaced rearwardly of the mold for permitting tilting movement of the rails relatively to the horizontal and corresponding variation in elevation of the front wall of the feed box above the mold, and means operatively connected to the rails proximate their fore ends to tilt the rails about said pivot and thereby vary the inclination of said feed box in accordance with the tilt of said rails, said last-mentioned means including a pair of levers extending fore and aft of the machine and respectively fulcrumed for tilting movement about relatively stationary supports located beneath the rails and immediately to the rear of the points of connection of said levers to said rails.

3. In a block making machine which operates automatically in repeating block making cycles having a mold, means for charging said mold with a determined volume of block molding material, and means for compacting the material in said mold to form a block and for stripping the block from said mold; the combination comprising a pair of laterally spaced parallel rails respectively disposed at opposite sides of the mold and extending fore and aft of the machine, a bottomless feed box having a front wall the bottom edge portion of which is adapted to scrapethe upper surface of moldable material deposited in the mold by said feed box, pivot means associated with said rails and spaced rearwardly of the mold for permitting tilting movement of the rails relatively to the horizontal and corresponding variation in elevation of the front wall of the feed box above the mold, and means operatively connected to the rails proximate their fore ends to tilt the rails about said pivot and thereby vary the inclination of said feed box in accordance with the tilt of said rails, said last-mentioned means comprising a lever system including a pair of levers respectively disposed adjacent the outer sides of said rails in underlying relation to said feed box, stationary fulcrum elements for said levers respectively disposed beneath the rails adjacent-the fore ends thereof and reversible motor driven means for commonly raising or lowering the rear ends of said levers to c'orrespondingly shift'the same about their fulcrum elements and so vary the inclination of said rails.

' '4. In a block making machine which operates automatically in repeating block making cycles having a mold, means for charging said mold with a determined volume of block moldingmaterial, and means for'comp acting the material in said mold to form a block and for stripping the block from said mold; the combination comprising a pair of laterally spaced parallel rails respectively disposed at opposite sides of the mold and extending fore and aft of the machine, a bottomless feed box movable along saidrails and having a front wall the bottom edge portion of which is adapted to scrap the upper surface of moldable material deposited in the mold leg said feed box, pivot means associated with said rails and spaced rearwardly of the mold for permitting tilting movement of' the rails relatively to the horizontal and corresponding variation in spacing of the front wall of the feed box above the mold, means operatively connected to the rails proximate their fore ends to tilt'the rails about said pivot and thereby vary the inclination of said feed box in accordance with the tilt of said rails, said last-mentioned means including a pair of rail-lifting members respectively disposed to either side of and below the plane of travel of the feed box and reversible power driven means commonly operative upon said lever members to tilt said rails, said power means being located below said feed box rearwardly of the mold box.

5. In combination, an open-topped bottomless feed box 12 for block molding machines for supplying the mold thereof with a determined volume of block molding material, said feed box having at its front end as a'fixed part thereof a cut-off bar'of a length suflicient to transversely r span; the mold, a stationary apron plate underlying and normally closing the bottom of said feed box, a pair of laterally spaced rails extending rearwardly from opposite "sides of said mold along which said feed box is adapted to travel during its reciprocation between a box-filling station and 'a mold charging station over the mold, pivot means associated with said rails and spaced rearwardly of the mold for permitting tilting movement of the rails relatively to the horizontal and corresponding variations 7 in elevation of the feed box cut-'ofl bar above the mold,

and means operatively connected to the rails proximate their fore ends to tilt the rails about said pivot and thereby vary the inclination of said feed box in accordance with the tilt of said rails, said last-mentioned means comprising a lever system including a pair of levers respectively disposed adjacent the outer sides of said rails in underlying relation to said feed box, stationary fulcrum elements for said levers respectively disposed beneath the rails adjacent the fore ends thereof and reversible motor driven means for commonly raising or lowering the rear ends of said levers to correspondingly shift the same about their fulcrum elements and so vary the inclination of said rails.

6. In the combination as defined in claim 4 wherein said reversible motor driven means is also disposed in underlying relation to the feed box.

References Cited in the file of this patent UNITED STATES PATENTS

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