US2237691A - Manufacture of building blocks - Google Patents

Description

April 1941., J STRAUB 2,2316% MANUFACTURE OF BUILDING BLOCKS Filed Jan. 11, 1939 2 Sheets-Sheet l April 8, 1941. F i RA -B 2,237,691

MANUFACTURE OF BUILDING BLOCKS Filed Jan. 11, 1939 2 Sheets-Sheet 2 19 TTDRJVEK Patented Apr. 8, 1941 UNITED STATESPATENT OFFICE iffiiiiffuitffilifilfff Application January 11, 1939, Serial No. 250,370

' 8 Claims. (01. 25-41) My invention is an improvement in the manufacture of concrete building blocks and the like, and in the method and apparatus involved in such manufacture.

In the making of such blocks of a suitable aggregate such as sand and gravel, cinders, etc. mixed with cement and Water and subjected to ressing or tamping operations, it is desirable in some cases to secure a smooth or approximately smooth outer surface. In my prior Patents No. 1,651,420, 1,682,359, 1,692,355, 1,987,721 and 2,099,946 are disclosed different means and various methods of accomplishing such results which have proven generally satisfactory.

In the development of concrete building units of the kind involved, it is becoming increasingly desirable to surface the blocks by trowelling action against the plastic face or faces, and the present invention has in view to improve and refine such treatment, in the manner hereinafter described.

As is generally understood in the art, and as fairly disclosed in my preceding patents, the trowelling operation tends to not only smooth the surface, but to regulate and standardize the associated finer particles of the aggregate and cement in forming a surfacing face.

In my present invention I apply a trowelling action by imparting to the movable side member or members of the mold box a series of alternating major movements interrupted by a larger series of alternating minor movements, thereby greatly increasing the efliciency of the trowelling function.

In other words, by imparting such a largely increased number of more or less minute back and forth intermediate minor movements to the facing element, it greatly accelerates the surface collection and congestion of the finer particles, as well as the smoothing surface treatment, with greatly improved results.

After prolonged experiments I have devised a machine which is capable of functioning in the desired manner above stated, utilizing a wall plate acting on the block face preferably during pressing or tamping, 0r aftertamping, or even when sufficiently plastic as to not require other than gravity settlement. 1

The invention is also successfully applicable to the modern so-called vibrating or jolting machines.

In connection with the further description, reference will be had to the accompanying for such treatment, in which:

present construction is in the gears II and I2.

Fig. 1 is a view in side elevation of a mold box provided with my improvement;

Fig. 2 is a longitudinal vertical section thereof on the line II-II of Fig. 3;

Fig. 3 is a plan View of Fig. 1;

Fig. 4 is a transverse sectional view on the line IV-IV of Fig. 2;

Figs. 5 and 6 are detail diagrammatic views illustrating the operation of the driving mechanism for the smoothing wall plate;

Fig. '1 is a view similar to Fig. 4 showing a vertical application of the smoothing treatment;

Fig. 8 is a detail view showing a modified form of driving gear.

The block forming mold box, of double movable side form shown, is provided with end Walls 2-2 rigidly mounted in any suitable manner as upon the supporting foundation 3. The side walls 4 are mounted between the edges of such end walls and suitable guiding braces or framing 5, whereby they are maintained in closing engagement with the end walls, providing the usual rectangular cavity of proper dimensions for the intended block, as for instance, an 8x8x1 6" unit. The usual pallet 6 is utilized, either with or without a base plate I, resting upon the transverse bottom 8 of any suitable construction, through which extend the ejecting rams, aa for discharge of the finished unit.

For the purpose of imparting the desired movements to the side plates 4 they are suitably connected with terminal journal bearings 9 at one end through which bearings extends the shaft 10 of a gear wheel H. A companion actuating gear I2 is mounted eccentrically on shaft I3 mounted in bearings M, which shaft is actuated in. any available manner, as by a train of gears l5, [6, for imparting power from any suitable prime mover, as motor M.

The particular feature of advantage in the As stated,.gear I2 in the construction shown, is mounted eccentrically so that as rotated its periphery will advance toward and recede from the normal pitch line of a concentric actuating gear. Such gear ll being connected by shaft ID will move the side plates 4 conformably, with return of the plates by action of springs H or the like, as for instance, by counterweights.

However the springs as shown are of proper strength and are anchored at Hi to stationary abutments of the framing and at the other end extend through flanges IQ of the outer ends of the, side plates, together with holding and adjusting nuts 20 for regulating the tension.

By such construction, or its equivalent, it will be seen that for each revolution of the driving gear or pinion l2 the side plates 4 will be thrust longitudinally, with return, to the same extent as will correspond to the eccentric throw of gear l2 in its action on gear ll, entirely irrespective of gear rotation.

However in order to provide for an increased series of minor or intermediate back and forth movements, occurring several times within the scope of the main back and forth movement alluded to, gear II is provided at intervals, say in every third or fourth tooth space, with a partly filling abutment 2|.

In other words, the normal space between the teeth is partly filled so that the entering tooth of pinion l2 will thus impart a sudden limited backward movement through gear ll, whether the eccentric gear I2 is advancing or receding in its rotation. Alternatively, gear ll may be of usual open tooth space type and driving gear 12 itself may have some of its teeth elongated, as Zla, Fig. 8, for thrusting action against gear II.

It will be understood also that various impulses of the same general kind may be had by combining a concentric pinion with a tooth space abutment gear, or an eccentric pinion with an ordinary gear, or as above described.

The net effect of such described movements is, as stated above, to insure a continuous back and forth main movement to the sides 4 with largely increased intermittent secondary back and forth movements continuously throughout the operation. The final effect of such treatment is to smooth, congest, and refine the texture of the block surface in the manner described.

Such effect is directly due to the alternating treatment imparted by the gear action and the reacting spring tension. I

Thus in Fig. 1 the driving pinion I2 is at its most receded position in full tooth engagement with gear H, and with the side plates 4 at their full receded position. As in Fig. 5, assuming the pinion I2 to be in substantially the same position, its engaging tooth is shown as having come into contact with the intra-tooth abutment 2|, due to which sudden clearance interruption, the entire gear H and its shaft and the sides 4 have been jarred backwardly a comparatively short distance, as at 22, with a corresponding short reversal by the following f ull depth tooth engagement. Such action is repeated each time a successive abutment comes into mesh with a tooth of the pinion, and is continued throughout the revolution of both gears.

As shown in Fig. 6, pinion l2 has made a one half revolution, forcing the side plates inwardly to the full extent of the entire eccentric variation, as indicated at 23. It will therefore be clear that as long as the motor M is in operation the plates will be subjected to the combined series of long and short movements as described.

It will be obvious that if desired, the driven gear may be regular without abutments between some of the teeth, and as a substitute for the abutments, some of the pinion teeth may be elongated, to produce the same effect as in Fig. 8.

I show in Fig. 7 a modified construction in which the side plates 4a are mounted for vertical movement and in which similar gears H and I2 impart similar up and down interrupted trowelling movements, in the same combination and relative frequency as in horizontal trowelling.

It will also be understood that gears I l and I2 may be transposed, i. e. the driving pinion may be truly concentric and driving an eccentric gear connected with the side plates.

Also, thatif desired the end plates may be actuated with stationary side plates in horizontal oscillation, or both side and end plates may be actuated in vertical oscillation, such change merely involving engineering design to suit conditions of use. With either form of machine it is also a fact that quite independent of the abutment/s 2| in either gear, the mere combination of a driving and a driven gear of continuously full open spaced teeth, one concentric and the other eccentric, will ensure a continuous series of the main full length oscillations of one or both wall plates, either side or end. The intermeshing gears, instead of following annular pitch line engagement, are always in close abutting insertion of the teeth, and impart to the plates a constant series of bumping impulses, producing the desired result on the face of the block in a high degree.

With either such arrangement the general operation of charging the plastic aggregate into the mold; cavity is followed, with tamping as by tampers b, if used, smoothing off of the surplus, and final ejection of the block and removal on its pallet as is commonly practiced.

It will be understood that the motor may be operated continuously or may be stopped and started for each successive unit manufactured, also that the block molding cavity may if desired be provided with a fixed wall at one side and a movable plate at the opposite side only.

Also that the construction of the machine may be changed and modified in various details, dimensions or otherwise dependent on the product being made, but that all such changes are to be understood as within the scope of the following claims.

What I claim is:

l. The method of making a concrete building block consisting in subjecting a molded body of plastic aggregate while in the mold and under tamping pressure to a plate surfacing treatment of back and forth major trowelling movements including intermittent alternating similar minor movements.

2. A block making machine consisting of a mold having a supporting frame and side and end plates carried thereby, one of said plates consisting of a movable trowelling member, and means for reciprocating the wall plate back and forth through full length strokes with alternating simultaneous multiple shorter length strokes consisting of a driving gear, a driven gear on the movable troweling member engaging the driving gear, and a spring connected with the movable troweling member for holding the said gears in mesh.

3. In combination, a block forming mold having a frame and side and end walls, one of the walls being slidably mounted on the frame for back and forth movement therein and provided with a shaft and a gear wheel having contacting abutments between some pairs of teeth, an intermeshing driving gear therefor, and a retracting spring for the wall exerting tension thereon towards the driving gear.

4. In combination, a block forming mold having a frame and side and end walls, one of the walls being slidably mounted on the frame for back and forth movement therein and provided with a shaft and a gear Wheel having contacting abutments between some pairs of teeth, an intermeshing eccentrically mounted driving gear therefor, and a retracting spring for the movable wall eluding a frame and side and end Walls, one of the Walls being slidably mounted on the frame for alternating back and forth movement therein and intermittent minor reverse forth and back movements, said movable wall having connected with it a toothed gear, an actuating gear therefor, one of said gears being provided with a minor number of abnormal depth teeth for effecting said reverse movements, and a retracting spring for the movable wall connected with the frame.

7. In combination, a block forming mold having a frame and, side and end walls, one of said walls being slidably mounted on the frame for back and forth movement therein and provided with a gear wheel, an intermeshing driving gear therefor, and means exerting continuous pressure on the slidable wall and its gear wheel towards the driving gear to effect abutting contact of the teeth of one of said gears between the teeth of the other gear and against the bottom of its tooth-receiving space.

8. In combination, a block forming mold having a frame and side and end walls, one of said walls being slidably mounted on the frame for back and forth movement therein and provided with a gear wheel, an intermeshing driving gear therefor, and a spring exerting continuous pressure on the slidable wall and its gear wheel towards the driving gear to effect simultaneous intermeshing of the teeth of both gears and positive abutting contact of the teeth of one of said gears against the inner bottom faces of the companion gear of such pair between the teeth thereof.

FRANCIS J. STRAUB.

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