US3412441A

US3412441A - Method and apparatus for consolidating poured concrete units

Info

Publication number: US3412441A
Application number: US520800A
Authority: US
Inventors: Wells Richard
Original assignee: Marietta Concrete Co
Current assignee: Marietta Concrete Co
Priority date: 1966-01-14
Filing date: 1966-01-14
Publication date: 1968-11-26
Anticipated expiration: 1985-11-26

Description

R. WELLS 3,412,441

METHOD AND APPARATUS FOR CONSOLIDATING POURED CONCRETE UNITS Nov. 26, 1968 3 Sheets-Sheet 1 Filed Jan. 14, 1966 I6 30 I72 M5 /66 I00 I02 INVENTOR- P/c/mw WELLS ATTORNEYS.

Nov. 26, 1968 R. WELLS 3,412,441

METHOD AND APPARATUS FOR CONSOLIDATING POURED CONCRETE UNITS Filed Jan. 14, 1966 5 Sheets-Sheet 2 INVENTOR- 2/0/4 20 Msus ATTORNEY$.=

Nov. 26, 1968 R. WELLS 3,412,441

METHOD AND APPARATUS FOR CONSOLIDATING POURED CONCRETE UNITS 5 Sheets-Sheet 3 Filed Jan. 14, 1966 I04 I n INVENTOR. /0 00/420 WHLS BY MW ATTORNEYS.

United States Patent 3,412,441 METHOD AND APPARATUS FOR CONSOLIDAT- ING POURED CONCRETE UNITS Richard Wells, Marietta, Ohio, assignor to Marietta Concrete Company, Marietta, Ohio, a corporation of Ohio Filed Jan. 14, 1966, Ser. No. 520,800 16 Claims. (CI. -41) ABSTRACT OF THE DISCLOSURE A vibrating table is provided wherein the amplitude of vibration may be adjusted, the cyclic rate of vibration may be altered and the downward movement of the table may be supplemented by inflatable means all at the discretion of the operator.

This invention relates to a method and device for con- 'solidating poured concrete forms, and more particularly by vibrating or oscillating the molds into which concrete is poured.

It is known in the prior art to vibrate a mold into which concrete has been poured to facilitate the settling of the concrete within the mold such that the form is properly filled and to facilitate the consolidation of the concrete therein. The prior art devices are generally characterized by a movable table operatively engaged with a mechanical driving means whereby the table may be oscillated to compact the concrete within the mold or form.

It has been found that the vibration characteristics of a particular type of concrete within a mold of a particular configuration but that the same vibration table gives unsuitable results when using another type of concrete for a differently configured mold. Accordingly, some investigation has been made to determine the possible variable characteristics of a vibration table whereby a single vibration unit may be utilized for a plurality of applications. It has been found that the amplitude of movement of the vibrating table, the cyclic rate of movement thereof and the downward forces acting on the mold at the lowermost point of travel all contribute to the quality of the finished product and the speed of consolidating concrete within a mold or form.

It is an object of the instant invention to provide a device for consolidating poured concrete units by vibrating the unit in which the amplitude of vibration or the cyclic rate thereof may be varied in accordance with the characteristics'of the form and concrete used.

Another object of the instant invention is to provide a device for vibrating concrete mold in which a movable platform is elevated and then dropped thereby jarring the concrete within the mold into close engagement with the interior configuration of the form.

Still another object of the instant invention is to provide a concrete vibrating table of the type described in which the downward gravitational jarring of the platform is supplemented by a compressible and expansible memher.

A further object of the instant invention is to provide a vibrating table utilizing an extensible fluid motor in which either the amplitude or cyclic rate of vibration may be varied.

A still further object of the instant invention is to provide a vibrating table in which an extensible fluid motor raises and then allows the table to drop thereby consolidating the concrete within the form with the fluid utilized to extend the motor bypassing the piston providing for the rapid movement of the vibrating table to create a consolidating jolt of large magnitude.

Another object of the instant invention is to provide a vibrating table having a stationary frame in a movable platform interconnected by a linkage acting to maintain the platform in a predetermined relationship with respect to the frame throughout the up and down movement of the platform.

A further object of the instant invention is to provide a control system for a vibratory table of the character described whereby the amplitude of vibration or the cyclic rate thereof may be conveniently varied by an operator.

A still further object of the instant invention is to provide a method for consolidating poured concrete units in which a mold may be filled with concrete and vibrated with the amplitude of vibration, the cyclic rate of vibration or the impact forces being variable at the command of the operator to take into account the variable physical characteristics of the concrete and the mold.

Other objects and advantages of the instant invention, as well as the invention itself, reside in the combinations of elements, arrangements of parts and features of construction and operation, all as will be more fully pointed out hereinafter and disclosed in the accompanying drawings wherein there is shown a preferred embodiment of this inventive concept.

In the drawings:

FIGURE 1 is a top plan view of the vibrating table of the instant invention;

FIGURE 2 is a side elevational view of the vibrating table of FIGURE 1 illustrating the movable platform, the stationary frame and the interconnections therebetween;

FIGURE 3 is an enlarged cross-sectional view of the vibratory table of FIGURES 1 and 2 taken substantially along line 3-3 of FIGURE 1 as viewed in the direction of the arrows and illustrating the extensible fluid motors acting to raise the movable platform;

FIGURE 4 is an enlarged cross-sectional View of the vibrating table of FIGURES 1 to 3 inclusive, taken substantially along line 44 of FIGURE 3 as viewed in the direction of the arrows and illustrating the compressible and extensible means for increasing the downward acceleration of the platform;

FIGURE 5 is a schematic view of the system to energize the compressible and expansible means to increase the downward acceleration of the platform;

FIGURE 6 is a partial organizational view illustrating the movable platform, the extensible fluid motors for raising the movable platform and the means for controlling the amplitude and cyclic rate of movement of the motors;

FIGURE 7 is a schematic view of a portion of the control system which acts to regulate the cyclic rate of vibration of the movable table;

FIGURE 8 is an enlarged side elevational view of the movable platform and stationary frame illustrating the linkage providing the interconnection therebetween to maintain the movable platform at a fixed attitude with respect to the stationary frame which is illustrated as horizontal;

FIGURE 9 is a front elevational view of one of the extensible fluid motors interconnecting the stationary frame and movable table;

FIGURE 10 is a longitudinal cross-sectional view of the fluid motor of FIGURE 9 taken substantially along line 10-1t3 thereof as viewed in the direction of the arrows and illustrating the condition wherein pressurized fluid is being injected into the lowermost chamber of the fluid motor to raise the piston and thereby elevate the movable platform;

FIGURE 11 is a cross-sectional view of the extensible fluid motor similar to that of FIGURE 10 but illustrating the condition wherein the movable platform is descending with fluid in the lowermost chamber of the extensible motor bypassing the piston; and

FIGURE 12 is a horizontal cross-sectional view of the fluid motor of FIGURES 9 to 11 inclusive, taken sub- 3 stantially along line 1212 of FIGURE 11 as viewed in the direction of the arrows.

Overall construction Referring now to the drawings in detail, wherein like reference characters designate like elements throughout the several views thereof, and more particularly to FIG- URES 1 to 3 inclusive, there is indicated generally at the vibrating table of the instant invention having :as its major components a stationary frame shown generally at 12 supported by underlying surface 14 and interconnected with a movable platform denominated generally at 16 by a stabilizing linkage indicated generally at 18. A plurality of extensible fiuid motors shown generally at 20 act to vibrate or oscillate platform 16 in accordance with the operation of a control system designated generally at 22 in FIGURES 6 and 7. In order to increase the downward forces upon movable platform 16 and to control these forces, a gravitational force supplementing device shown generally at 24 is provided, the details of which will be more fully explained hereinafter.

Frame, movable platform and stabilizing linkage Frame 12 is provided with a pair of longitudinally extending supports 26 interconnected by a baseplate 28 and a vertically spaced parallel plate 30 to which fluid motors 20 may be fixedly secured as more fully explained hereinafter. Movable platform 16 includes an article supporting surface 34 from which depends a pair of longitudinal beams 36 overlying supports 26 of stationary frame 12.

Stabilizing linkage 18 interconnects movable platform 16 and stationary frame 12 and includes a pair of movement translating structures shown generally at 38, 40 spaced along the lengthwise dimension of table 10. As may be seen most clearly in FIGURE 8, each of structures 38, 40 includes a bell crank shown generally at 42, 44 pivotally mounted by a pin 46, 48 on a depending arm 50, 52 integral with movable platform 16. Long legs 54, 56 of

bell crank

42, 44 are pivotally interconnected with support 26 of frame 12 by

links

58, 60 and

pivot pins

62, 64, 66, 68.

A short leg 70 of bell crank 42 extends upwardly and is pivotally interconnected by pivot pin 72 to a diagonal strut 74. The other end of strut 74 is pivotally connected to a downwardly extending short leg 76 of bell crank 44 by a pivot pin 78. It should be understood that shafts 46, 48 extend laterally across platform 16 with another pair of bell cranks similar to

bell cranks

42, 44 being rotatably mounted thereon. Elements identical to

links

58, 60 and strut 74 are provided on the opposite side of table 10 to construct another linkage 18 to insure the parallel movement of platform 16 with respect to frame 12.

It will be seen that linkage 18 mounts movable platform 16 for up and down movement with both of

hell cranks

42, 44 rotating in a counterclockwise direction upon the imposition of a force F upon platform 16. If an unbalanced force is placed on platform 16 tending to tilt article supporting surface 34, one of

bell cranks

42, 44 will tend to rotate a greater extent than the other resulting in the movement of diagonal strut 74, thereby rotating the other of

cranks

42, 44 to provide for equal rotary movement of both structures 38, 40. It should be apparent that structures 38, 40 are constructed to avoid interference between strut 74 and

links

58, 60 and long legs 54, 56 of

hell cranks

42, 44.

Gravitational force supplementing means It has been found that the primary beneficial effect of vibrating poured concrete molds is achieved when movable platform 16 moves from an elevated position and is suddenly stopped or jarred by contact with an immovable object. Prior art devices create this jar by reversing the direction of movement of the platform elevating means or by impacting the table against an immovable object. It will be noted, however, that the movement of the platform from the elevated position to the depressed position is normally achieved by the reversing of the direction of movement of the platform elevating means or by allowing the table to fall by gravity.

It has been found that the effectiveness of the vibrating in consolidating the unit is directly proportional to the magnitude of the jolt at the lowermost point of travel. Gravitational force supplementing devices are used, therefore, to overcome any friction in the linkage and to increase the jolt to a point greater than that achieved by mere gravitational force alone. Gravitational force supplementing devices 24 include a pair of L-shaped brackets shown generally at 80, 82 with a compressible and expansible member shown generally at 84 positioned therebetween. L-shaped bracket includes a first support 86 depending from movable platform 16 and carrying a first plate 88 at right angles thereto. Bracket 82 includes a second support 90 extending upwardly from stationary frame 12 and carrying a second plate 92 perpendicular thereto positioned above first plate 88 and between first plate 88 and movable frame 16.

Compressible and expansible member 84 acts as a spring and comprises a tubular compartment 94 of an elastic material, such as rubber, and is positioned to be compressed by the movement of

plates

88, 92 toward each other. As may be seen in FIGURE 5, each of the compartments 94 is connected to a header 96 by a branch line 98 with header 96 being connected to a pressure regulator 100 and an air compressor 102 by suitable air lines 104. It will be readily apparent that the actuation of air compressor 102 will deliver a pressurized gas interiorly of tubular compartments 94, the pressure of which may be controlled by pressure regulator 100. When fluid motors 20 are actuated to elevate movable platform 16, tubular compartment 94 will be compressed. When platform 16 starts to fall, compartment 94 will expand, thereby separating

plates

88, 92, which in turn act to increase the downward speed of platform 16.

Since the pressure within compartments 94 may be varied by the operator it will be apparent that an important factor in consolidating concrete molds, i.e. the magnitude of the jolt at the lowermost point of travel of platform 16, thereby lending a degree of flexibility to vibratory devices which have previously been characterized by immutable vibrating characteristics.

Fluid motor construction Referring now to FIGURES 9 to 12 inclusive, fluid motor 20 is illustrated as comprising a cylinder 106 aflixed to a base 108 forming a central aperture 110 with base 108 being securely mounted on base plate 28 of frame 12 such that aperture 110 is coaxial with an opening 112 in plate 30. The upper end of cylinder 106 is closed by a cap 114 forming a threaded fluid outlet 116 and a longitudinal opening 118 to accommodate a piston rod 120 interconnecting a slidably mounted piston shown generally at 122, interiorly of cylinder 106, and movable platform 16.

Piston 122 includes a cylindrical body 124 threadably receiving piston rod 120 and forming a plurality of longitudinally extending openings 126 which comprise part of a bypass means as more fully explained hereinafter. Another portion of the bypass means is a plug shown generally at 128 having a body 130 secured by screws 132 or other conventional fasteners to piston body 124. Body 130 forms a plurality of L-shaped passageways 134 connecting openings 126 to an equal number of radial openings 136 in a tubular member 138 which is closely received by aperture 110 of base 108 and opening 112 of base plate 30.

Tubular member 138 is illustrated as fixedly secured to plug 128 and piston 122 by welds 139, although tube 138 and plug 128 may be made of a one piece member, and

forms a plurality of radial apertures 140 below plug 128 in order to inject a pressurized fluid into fluid chamber 142 to raise piston 122 and thereby elevate movable platform 16. The injection of pressurized fluid into chamber 142 is effected through a plurality of openings 144 formed in the lowermost end of tube 138 with openings 144 being in fluid communication with a housing 146 having a threaded fluid inlet 148 in which a threaded fluid connection may be secured. As may be seen most clearly in FIGURE 10, fluid injected through inlet 148 will pass through an interior passageway 150 of tube 138 and exit out of radial apertures 140 into fluid chamber 142 thereby raising piston 122 and movable platform 16.

Positioned interiorly of passageway 150 is a valve spool shown generally at 152 having a central shank 154 carrying a valve plug 156 at the upper und thereof for selectively opening and sealing off radial openings 136 of tube 138. The lower end of shank 154 carries a combined valve plug and cam follower 158 for selectively opening or sealing otf openings 144 in the lower end of tubular member 138. It will be seen that shank 154 is of a suflicient length such that when valve plug 156 closes radial openings 136, valve plug 158 is positioned below openings 1 44- and when valve plug 156 moves upwardly away from radial openings 136, valve plug 158 closes openings 144.

A helical spring 160 connects piston 122 and valve spool 152 to continually bias spool 152 downwardly into engagement with the cam 162 which is rotated to elevate valve spool 152 at predetermined times as more fully explained hereinafter. As may be seen in FIGURE 10, the normal position of valve spool 152 is such that fluid will enter inlet 148 and pass into fluid chamber 142 to elevate piston 122. When cam 162 elevates Valve spool 152, valve plug 158 will seal off fluid flow through inlet 148 and uncover radial openings 136. Since cam 162 is timed such that valve spool 152 is raised at the uppermost point of travel of piston 122, the gravitational load on platform 16 coupled with the forces produced by supplementing devices 24 will urge piston 122 downwardly in cylinder 106. When piston 122 travels downwardly in cylinder 106, the fluid previously trapped in chamber 142 will pass through openings 140* and through

openings

136, 134, 126 to a fluid chamber 164 above piston 122.

Control system A cam housing 166 surrounds cam 162 and receives a shaft 168 therethrough which is secured to cam 162 by a suitable key 170. As will be more fully explained hereinafter, shaft 168 will be rotated according to a fixed plan whereby cam 162 will elevate valve spool 152 when piston 122 and movable platform 16 reach the uppermost limit of intended movement. As may be seen in FIGURES 1 to 3 inclusive, a plurality of fluid motors 20 are provided in a symmetrical fashion under movable platform 16 with shafts 168 being interconnected by suitable endless members 172 so that shafts 168 will rotate together to simultaneously actuate valve spool 152 of each fluid motor 20.

Referring now to FIGURE 6, one of shafts 168 is rotated by a conventional hydraulic motor 174 through an articulatable drive connection shown generally at 176 of any suitable type. Since cam housings 166 are threadably connected with tubular member 138, it will be apparent that housings 166 undergo up and down movement along with piston 122. Accordingly, housings 166 may be spring mounted, cushioned in any other manner or free floating to avoid injury thereto resulting from contact with base plate 28 of frame 12. It will be seen, therefore, that drive connection 176 should be articulatable and may be a universal drive connection. The movement of shafts 168 may be constrained to a vertical plane by suitable guides to avoid movement 6 toward each other under the influence of the tension in endless belts 172.

Hydraulic motor 174 is powered through a hydraulic drive system shown generally at 178 comprising a reservoir 180, a conventional hydraulic pump 182 and a valve shown generally at 184 interconnected by suitable hydraulic lines 1 86 into a closed system. Although fluid motors 20 may be of the compressed air type, it has been found preferable to utilize hydraulic fluid to propel piston 122 within cylinder 106 such that reservoir 180 and pump 182 of drive system 178 may be connected in a suitable manner to fluid inlet 148 and fluid outlet 116 of motor 20.

Valve 184 includes a housing 188 positioned in the hydraulic circuit of drive system 178 with a spool 190 slidably mounted within housing 188 with spool 190 forming the customary fluid passageway 192 which may be positioned adjacent fluid lines 186 for passing hydraulic fluid. Spool 190 is connected by a rod 194 to an air cylinder 196 powered through an air line 198 which is in turn connected to a suitable air compressor, such as A compressor 102. A solenoid operated valve 200 is positioned on air cylinder 196 for selectively opening and closing air line 198 with the solenoid thereof being provided with a pair of electrical outlets 202, 204.

Valve 184 is of the normally closed type, as illustrated in FIGURE 6, and will be opened by the actuation of air cylinder 196 with a spring or the like (not shown) acting to return spool 190 to the closed position shown. The delivery of electrical energy through electrical outlets 202, 204 will open air lines 198 to actuate air cylinder 196 thereby positioning valve passageway 192 adjacent hydraulic lines 186 to deliver hydraulic fluid to motor 174 thereby rotating drive connection 176 and shafts 168. The interruption of electrical current through outlets 202, 204 will result in the closing of valve 184 and consequently stop the rotation of motor 174, drive connection 176 and shafts 168.

As will be more fully explained hereinafter, the structure of FIGURE 7 controls the cyclic rate of vibration of platform 16 while an amplitude limit switch shown generally at 206 in FIGURE 7 controls the amplitude of movement of platform 16. In addition to limit switch 206 and the hydraulic drive mechanism of FIGURE 6, control system 22 includes a cam 208 forming a lobe 210 mounted for rotation with one of shafts 168 to actuate a first normally closed rotation stopping switch shown generally at 212, a normally closed second rotation stopping switch indicated generally at 214 and a reset switch shown generally at 216 which acts to cycle a relay shown generally at 218 and a timer shown generally at 220, the operations of which will be more fully explained hereinafter. For purposes of convenience, some of the electrical wires leading from the enumerated elements are marked and to facilitate the description and understanding of the electrical circuitry of control system 22.

As may be seen in FIGURE 7, lobe 210 trails the lobe of cam 166 with first rotation stopping switch 212 being positioned such that the rotation of shaft 168 is stopped immediately before cam 166 elevates cam follower 158 and consequently spool 152. It will be recalled that valve spool 190 of hydraulic drive system 178 is of the normally closed type until solenoid valve 200 is energized thereby actuating air cylinder 196 to drive motor 174. Before lobe 210 of cam 208 actuates first rotation stopping switch 212, solenoid valve 200 is energized through a first solenoid energizing circuit comprised of a lead 222 connected to the positive side of a power source, switch 214, a wire 224 connecting switch 214 to switch 212, a wire 226 leading from switch 212, a branch line 228 connected to electrical outlet 202 through solenoid 200 exiting through outlet 204 which is connected to the negative side of the power source.

It will be apparent that solenoid 200 is energized to drive hydraulic motor 174 until lobe 210 contacts an outwardly biased plunger 230 of switch 212. Plunger 230 carries a contact 232 which is separated from a contact 234 on the end of wire 226 thus severing the first solenoid energizing circuit at which time spool 190 is returned to the normally closed position thereby stopping hydraulic motor 174. Since extensible motors are driven independently from motor 174, the cessation of motor 174 will have no effect upon the movement of piston 122 within motor 20.

When movable platform 16 approaches the desired upper limit of movement, it contacts an outwardly biased plunger 236 of amplitude limit switch 206 which carries a plate 238 acting to close

contacts

240, 242 within switch 206. Contact 240 is connected by a lead 244 to the negative side of the power source with contact 242 being connected by a pair of wires 246, 248 to a contact 250 and a coil 252 of relay 218. The other side of coil 252 is connected by a suitable wire 254 to reset switch 216 with the circuit being completed through a lead 256 leading to the positive side of the power source. For purposes of convenience, these components are entitled a first coil energizing circuit.

It will be seen that coil 252 will be energized upon the depression of plunger 236 by movable platform 16 which causes contact 250 to engage a contact 258 and causes

contacts

260, 262 of relay 218 to close. Contact 258 is connected with a branch line 268 leading to the negative side of the power source. It will be apparent that the second coil closing circuit comprised of lead 256, switch 216, wire 254, coil 252,

contacts

250, 258 and branch line 268 will energize coil 252 even through the first coil energizing circuit is broken by the separation of

contacts

240, 242 of switch 206.

As previously mentioned, the energization of coil 252 closes

contacts

260, 262 thereby energizing solenoid valve 200 through a second solenoid energizing circuit comprising lead 222, switch 214, wire 224, a wire 270 connecting wire 224 to contact 260, a wire 272 connecting contact 262 to branch line 228, electrical outlet 202 through solenoid 200 and electrical outlet 204 to the negative side of the power source.

Accordingly, the depression of plunger 236 will energize solenoid valve 200 thereby actuating hydraulic motor 174 to rotate shaft 168 such that cam 162 elevates cam follower 158 and spool 152 to start the downward descent of movable platform 16. Since the second coil closing circuit maintains contacts 260' 262 in closed relation, hydraulic motor 174 will continue rotation even through plunger 236 separates from movable platform 16.

The rotation of shaft 168 advances cam 208 until cam lobe 210 comes into contact with an outwardly biased plunger 274 of second rotation stopping switch 214 which carries a contact 276 out of engagement with a contact 278 in communication with lead 222 thereby severing both the first and second solenoid actuating circuits which, of course, results in the stopping of hydraulic motor 174 and the rotation of shaft 168.

Hydraulic motor 174 will remain immobile until timer 220 acts. Timer 220 may be of any suitable type, but should have a variable timing characteristic whereby the second cessation of rotation will continue for a predetermined length of time which may be varied by an operator. A branch line 280 leads from the positive side of the power source to timer 220 and is electrically connected, after the predetermined lapse of time, to a wire 282 connected with wire 224 and consequently contact 232 of first rotation stopping switch 212. Since plunger 230 of switch 212 is outwardly biased and since lobe 210 is now positioned under switch 214, electrical communication will exist through switch 212, wire 226, branch line 228, electrical outlet 202, solenoid operating valve 200 and electrical outlet 204 to the negative side of the power circuit thereby establishing a third solenoid energizing circuit. When timer 220 acts to electrically connect branch line 280 and wire 282, it will be apparent that solenoid 200 will be energized thereby starting motor 174 to rotate shaft 168 and cam 208.

When cam lobe 210 passes away from second rotation stopping switch 214, it should be remembered that coil 252 of relay 218 is energized with deactivation being necessary before lobe 210 engages first rotation stopping switch 212. This is apparent because the breaking of

contacts

232, 234 of switch 212 will not cease rotation of motor 174 because the second solenoid energizing circuit is also closed. Accordingly, reset switch 216 is positioned behind second rotation stopping switch 214 and includes an outwardly biased plunger 284 carrying

contacts

286, 288. Prior to the depression of plunger 284, contact 286 is in communication with a contact 290 connected to lead 254. The depression of plunger 284 acts to sever the second coil energizing circuit thereby setting the stage for lobe 210 to engage switch 212 thereby stopping the rotation of shaft 168 as previously mentioned.

Contact 288 of reset switch 216 is normally out of engagement with a contact 262 connected to a wire 264 leading to a reset mechanism within timer 220. The electrical circuit of the reset mechanism is completed through a branch line 296 leading to the negative side of the power source. The depression of plunger 284 by cam lobe 210 operates to close

contacts

288, 292 for delivering electrical energy to the reset mechanism whereby timer 220 may be conditioned for another cycle of rotation.

It will be seen that the amplitude of vibration of movable platform 16 may be changed by adjusting the position of amplitude limit switch 206 as by the use of an adjustable bracket or the like. It will also be apparent that the cyclic rate of vibration of platform 16 may be changed by adjusting timer 220 to change the lapse time as previously mentioned. It should be noted that the cyclic rate of vibration is controlled by timer 220 but that the maximum rate of vibration is dependent upon the capacity of the hydraulic pump delivering pressurized fluid to extensible motors 20. Even if timer 220 is set for a zero lapse, platform 16 will undergo the entire amplitude of vibration since timer 220, in effect, acts only to set a rate of vibration less than the maximum possible from the equipment.

Summary of operation When a concrete filled mold is placed on platform 16, amplitude limit switch 206 Will be adjusted to provide the desired amplitude of vibration with timer 220 being set to give the desired cyclic rate of vibration. Air compressor 102 and pressure regulator will be adjusted to deliver the desired pressurized gas within tubular compartments 94 with the power source being turned on. The injection of pressurized fluid into chamber 142 will raise piston 122 and platform 16. While the injection of pressurized fluid into chamber 142 is taking place, fluid motor 174 will be rotating shaft 168, cam 162 and cam 208.

The raising of platform 16 will act to compress member 84 between first and

second plates

88, 92 thereby storing energy in the pressurized gas contained therein.

A suitable master switch at the power source may be closed to deliver electrical energy to control system 22 whereby motor 174 will begin to rotate shaft 168. Similarly, pressurized fluid will be delivered to motors 20 to elevate platform 16. When cam lobe 210 engages first rotation stopping switch 212, hydraulic motor 174 will be halted although the rise of piston 122 Within fluid motor 20 will continue because of the independence of the fluid delivery systems thereto. When platform 16 reaches its uppermost limit of travel, it will engage amplitude limit switch 206 thereby starting the rotation of hydraulic motor 174 which results in the rotation of shaft 168 and cam 162 thereby elevating valve spool 152 to cease fluid delivery to chamber 142 and to actuate the bypass means through piston 122.

As soon as the bypass is opened, platform 16 will begin its descent, urged by the expansion of tubular compartment 94 with the fluid trapped in chamber 142 passing through piston 122 into chamber 164 as previously mentioned. Since shaft 168 is rotating, cam lobe 210 will engage second rotation stopping switch 214 to cut off hydraulic motor 174 and allow timer 220 to effect the desired cyclic rate of vibration. As soon as timer 220 has waited the appropriate length of time, hydraulic motor 174 will restart with cam lobe 210 engaging reset switch 216 to deenergize coil 252 and actuate the rest mechanism within timer 220.

It will be apparent that both the amplitude, rate of vibration and impact force may be varied to adjust the vibrating characteristics of table in accordance with the physical characteristics of the concrete used as well as the configuration of the mold. To illustrate the value of adjusting and manipulating these vibrating characteristics, it has been found that light weight molded units require greater use of gravitational force supplementing device 24 and a higher cyclic rate of vibration while heavier mold require a lesser amplitude of vibration because the weight of the unit itself contributes to the compacting process. It should be understood, however, that the determination of an optimum set of vibrating characteristics is largely an empirical process.

It is now seen that there is herein provided an improved method and apparatus for consolidating poured concrete units having all of the objects and advantages of the instant invention and others, including many advantages of great practical utility and commercial importance.

Since many embodiments may be made of the instant inventive concept, and since many modifications may be made in the embodiment hereinbefore shown and described, it is to be understood that the foregoing is to be interpreted merely as illustrative and not in a limiting sense.

I claim:

1. A device of the character described comprising:

a stationary frame;

a table movably mounted on the stationary frame for up and down movement; means operatively connected to the table for vibrating the table between upper and lower limits; and

means for maintaining the table in a substantially horizontal position throughout the range of movement between the upper and lower limits, the maintaining means comprising a pair of spaced apart bell cranks pivotally mounted on the same side of the platform, one of the bell cranks having an upwardly extending arm, one of the bell cranks having a downwardly extending arm;

a diagonal strut pivotally interconnecting the upwardly extending arm and the downwardly extending arm; and

a pair of links, each link pivotally connecting the other arm of the bell crank and the frame.

2. A vibrating table comprising:

a stationary frame;

a table vertically movably mounted on the stationary frame for up and down movement;

at least one extensible fluid motor interconnecting the frame and the table for cyclically moving the table up and down, the fluid motor including a cylinder arranged between the table and frame;

a piston reciprocably mounted in the cylinder;

means forming a normally closed fluid bypass between one of the fluid chambers formed by the piston and cylinder and the fluid outlet;

a piston rod, affixed to the piston, extending through one end of the cylinder; and

means for injecting a pressurized fluid into the one fluid chamber for producing relative movement between the piston and cylinder to separate the table and frame; and

means for varying the cyclic rate of the fluid motor including valve means for interrupting the flow of pressurized fluid into the one fluid chamber and opening the bypass to allow escape of the pressurized fluid from the one fluid chamber to the fluid outlet allowing the table and frame to move relatively toward each other.

3-. The vibrating table of claim 2 wherein the fluid outlet is formed by the cylinder and is in communication with the other fluid chamber formed by the cylinder and piston and the bypass forming means includes at least one passageway through the piston.

4. The vibrating table of claim 2 wherein the valve means includes means for substantially simultaneously interrupting the flow of pressurized fluid into the one fluid chamber and opening the bypass to allow escape of the pressurized fluid from the one fluid chamber to the other fluid chamber allowing the table and frame to move relatively toward each other.

5. The vibrating table of claim 2 including means for supplementing the gravitational attraction of the movable platform and stationary frame.

6. The vibrating table of claim 2 wherein the cyclic varying means includes means for actuating the valve means a predetermined number of times per unit time and means for varying the predetermined number of times per unit time.

'7. The vibrating table of claim 6 wherein:

the valve actuating means includes a rotatable shaft;

a valve operating cam mounted on the shaft for engagement with the valve; and

means for rotating the 'shaft; and

the varying means includes means for stopping and starting the rotating means.

8. The vibrating table of claim 7 wherein the stopping and starting means includes:

a switch operating cam, on the shaft, for rotation therewith;

a first rotation stopping switch, positioned for engagement with the switch operating cam before the valve operating cam engages the valve, for stopping the rotating means;

an amplitude limit switch adjustably mounted in the path of movement of the platform for starting the rotating means upon contact with the platform;

a second rotation stopping switch, positioned for engagement with the switch operating cam after the valve operating cam engages the valve, for stopping the rotating means; and

a timer for starting the rotating means after a predetermined lapse of time commencing with the second stopping of the rotating means.

9. A vibrating table comprising:

a stationary frame;

a platform movably mounted on the stationary frame for up and down movement;

means operatively connected to the platform for moving the platform to an upper position and allowing the platform to fall to a lower position; and

means for supplementing the downward movement of the platform in addition to the normal gravitational forces, the supplementing means comprising inflatable means operatively interconnecting the stationary frame and the movable plat-form;

means for delivering an expansible fluid to the inflatable means; and

means for controlling the pressure of the fluid delivered to the inflatable means.

10. A vibrating table comprising:

a stationary frame;

a platform movably mounted on the stationary frame for up and down movement;

means for supplementing the downward movement of the platform in addition to the normal gravitational forces, the supplementing means comprising a first plate carried by the platform;

a second plate carried by the frame above and overlying the first plate;

a compressible and expansible means between the first and second plate moving the plates away from each other to supplement gravitational approach of the frame and platform.

11. The vibrating table of claim 10 wherein the compressible and expansible means includes an elastic receptacle for carrying an expansible substance.

12. The vibrating table of claim 11 wherein the compressible and expansible means further includes means for injecting a pressurized gas into the elastic member.

13. The vibrating table of claim 12 wherein the gas injecting means includes means for controlling the pressure of the gas injected.

14. A vibration mechanism comprising:

a frame;

a table movably mounted on the frame for up and down movement;

means for cyclically moving the table between upper and lower limits;

means for regulating the cyclic moving means in response to table position and in response to the cyclic rate of the moving means, the regulating means comprising means for relaxing the moving means to allow the table to gravitate to the lower limit;

means for controlling the relaxing means;

means responsive to the presence of the table at the upper limit for conditioning the controlling means to enable the controlling means to actuate the relaxing means upon the passage of a predetermined time interval greater than the time interval necessary for the cyclic moving means to move the table to the upper limit; and timer means responsive to the predetermined time interval enabling the controlling means to actuate the relaxing means for controlling the cyclic rate of the moving means. 15. The vibration mechanism of claim 14 wherein: the cyclic moving means comprises a piston and cylinder arrangement, operatively connected with the table, having a fluid inlet and a fluid exhaust outlet; and a source of pressurized fluid in communication with the fluid inlet; the relaxing means comprises normally closed valve means controlling the exhaust outlet; and the controlling means includes a valve actuator for moving the valve means to an exhaust position in response to the table presence responsive means and the timer means. 16. The vibration mechanism of claim 14 further comprising:

means for supplementing the gravitational movement of the table from the upper limit toward the lower limit.

References Cited UNITED STATES PATENTS 858,232 6/1907 Taylor et al. 941,999 11/1909 Lewis. 991,381 5/1911 Simmers 259--72 1,113,995 10/1914 Lewis. 3,211,432 10/1965 Van Rosen.

WILLIAM J. STEPHENSON, Primary Examiner.