US3306174A

US3306174A - Vibratory tamper

Info

Publication number: US3306174A
Application number: US376924A
Authority: US
Inventors: Alvero A Wardell
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-06-22
Filing date: 1964-06-22
Publication date: 1967-02-28
Anticipated expiration: 1984-02-28

Description

United States Patent Ave,

This invention relates to a vibratory tamper adapted for use in tamping plastic material prior to setting and curing. The tamper is particularly adapted for use in tamping concrete while in a plastic or amorphic state and permits a combined tamping and smoothing operation to be performed by a single workman.

Previously available tampers for plastic substances, such as concrete and the like, merely provided a tamping element connected to a source of power to effect reciprocation of the element. Certain of the prior art devices included a crank and connecting rod or similar eccentric drive mechanism between the source of power and the tamping element to impart the desired reciprocating movement to the tamping element. An inherent characteristic of such power transmission mechanisms is a lateral thrust component in the force transmitted to the tamping element, the amplitude of the lateral thrust being dependent upon the length of the crank, or the eccentricity of the drive mechanism. Consequently, vibrations substantially normal to the direction of reciprocation of the tamping element are incurred by such tampers.

In certain prior art tampers, such vibrations are horizontally oriented and are utilized in floating or smoothing the concrete by laterally opposed floating shoes rigidly connected to the framework of the tamper. A specific example of such a construction is illustrated in United States Patent No. 2,746,367 to Ferguson. In many operational environments the vibrations in a horizontal plane have not been found to be desirable in tamping and floating of the concrete, and unnecessarily add to the total vibration of the assembled machine. Consequently, workmen operating such machines are subjected to enervating and fatiguing vibrations. In addition, the requisite laterally opposed pair of shoes are necessary to balance the vibrations imparted to the shoes through the framework. Consequently, such a construction precludes a combined tamping and floating or smoothing operation, and unnecssarily adds to the total mass of the machine.

Accordingly, it is an object of the present invention to provide a vibratory tamper which includes a power transmission mechanism which eliminates or minimizes undesirable vibratons occurring in a generally horizontal plane.

Another object is to provide a vibratory tamper which permits the simultaneous performance of tamping and smoothing operations by a single workman.

Another object is to provide a tamper having a tamping element mounted for reciprocation in a generally vertical plane of movement and provided with resilient connecting means in the power train to absorb a major portion of the vibrations otherwise transmitted to the workman operating the tamper.

Other objects and advantages of the present invention will subsequently become more clearly apparent upon reference to the description in the specification.

In the drawing:

FIG. 1 is a top plan view of the vibratory tamper of the present invention with portions broken away for illustrative convenience.

FIG. 2 is a rear elevation of the vibratory tamper of FIG. 1.

FIG. 3 is a transverse vertical section through the tamper taken on line 3-3 of FIG. 2.

Referring more particularly to the drawing, a vibratory tamper embodying the principles of the present invention provides a frame generally indicated at 10 having an elongated substantially rectangular base plate 11 of substantially rigid sheet material, such as aluminum, stainless steel or the like. The frame includes a pair of upstanding pedestals 14, each having a lower mounting flange 15, a pair of lower oppositely spaced boss members 16 having bores 17 and an upper pillow block bearing mounting structure 18. The pillow block structure includes an upper bearing cap 1 constrained on the pedestal by bolt and nut assemblies 2G. The frame further provides a manually engageable inverted substantially U-shaped handle 22 having lower mounting ends 23 disposed in over-lying relation to the flanges 15 of the pedestals 14.

An elongated float shoe 25 having a leading portion 26 and a trailing portion 27 is closely associated with the above described frame components. The leading portion of the shoe provides a top wall 30 which is disposed between the mounting flanges 15 of the pedestals 14 and the base plate 11. The lower mounting ends 23 of the handle 22, the flanges 15 and the base plate 11 are interconnected by bolt and nut assemblies 32 extended therethrough, as shown in FIG. 2. The leading portion 26 of the shoe further includes depending spaced substantially parallel side walls 36 having forward and rearward

lower edges

37 and 38, respectively, disposed in substantially horizontal coplanar relation. The top and side walls thereby cooperate to define an elongated downwardly opening channel 39. The trailing portion 27 of the shoe provides a trowel member at} integrally rearwardly extended from the rearward lower edge 38 and has a lower substantially planar surface 42 in coplanar relation with the edges.

An elongated drive shaft 45 is rotatably mounted at its ends in bearings 46 mounted in the pillow blocks 18 of the spaced pedestals 14 in upwardly spaced substantially parallel relation to the top wall 34 of the float shoe 25. The drive shaft includes extended end portions 47 disposed transversely outwardly of the bearings. A pulley wheel 50 is mounted on the drive shaft adjacent to one end thereof for mounting a V-belt 52. The V-belt is trained about a drive pulley 54- mounted on the drive shaft 55 of a motor 56 of any suitable form, such as an internal combustion engine, as illustrated. The motor is mounted on a support plate 60 mounted on the top wall 30 of the shoe intermediate its ends by a plurality of bolt and nut assemblies 62. The support plate includes a rearwardly overhanging motor mounting portion 64 having a pair of depending legs 65 of resilient material, such as rubber or the like, engageable with the upper surface of the trowel 40. i

A pair of eccentric drive mechanisms, generally indicated by the reference numeral 70, are individually mounted on each of the extended ends 47 of the drive shaft 45 outwardly adjacent to the pillow blocks 18 of the pedestals 14. The eccentric drive mechanisms each provide an inner substantially circular throw member 72 eccentrically mounted on the extended ends of the drive shaft. A roller bearing 74 is mounted in circumscribing relation on the throw member and has an outer race 75 providing an integral radially downwardly extended connecting rod 78. The connecting rod provides a lower screw threaded end 79 which mounts a pair of opposed adjusting nuts 80 thereon.

A pair of support members or cross heads individually mount a pair of spaced depending legs or bolts 86 adjacent to their ends which provide lower screw threaded ends 87. The lower end 79 of each connecting rod 78 is loosely extended through an enlarged bore 88 intermediate the ends of its respective cross head. A pair of bushings 89 of a diameter larger than the diameter of the bore 88 and of resiliently flexible material, such as rubber or the like, are disposed on the lower end of the connecting rod between the adjusting nuts 80 and on opposite sides of the cross head. The adjusting nuts are tightened against their respective bushings resiliently to couple the connecting rod to the cross head. Elongated spacer sleeves 90 are individually mounted on the bolts for extension through the bores 17 in the boss members 16 of the pedestals and through the top wall 30 of the shoe 25 and the base plate 11. A pair of seal members 92 of felt material or the like are disposed about the sleeves between the boss members 16 and the mounting flanges 15 of the pedestals to preclude upward travel of concrete and other extraneous matter into the bores 17.

An elongated substantially rectangular tamper 94 is provided of a size to be received within the channel of the leading portion 26 of the shoe. The tamper includes a rectangular frame 95 having upstanding side walls 96 supporting a lower substantially planar reticulated tamping surface 97 of expanded metal material or the like. The tamper has a pair of cross bars 93 providing tapped bores screwed threadably to receive the lower threaded ends 87 of the bolts 86 of the cross head which tighten the frame 95 of the tamper tightly against the sleeves 90.

Operation The operation of the described embodiment of the subject invention is believed to be clearly apparent and is briefly summarized at this point. After the concrete to be finished has cured sufiiciently to support a workman, the vibratory tamper of the present invention is disposed on the surface thereof and the motor 56 started to impart rotation to the drive shaft 45. Such rotation causes eccentric rotary movement of the throw member 72 which imparts a substantially vertical reciprocating motion to the connecting rod 78. As previously described, such movement-also produces a lateral thrust component proportional to the eccentricity of the throw member 72 on the drive shaft. Such lateral thrust is, however, absorbed and substantially isolated from the cross head and tamper by the resilient bushings 89 and unrestricted lateral movement of the connecting rod within the enlarged bore 88. As a result, the only motion transmitted is the afore described substantially vertical reciprocating movement of the cross head which is transmitted by way of the connecting bolts 85 to the tamper 94. The tamper is reciprocated within the channel 39 of the leading portion of the shoe ahead of the trowel 40 as the tamper is motivated in a rectilinear path of travel incident to a pulling force on the forwardly extended handle 22 by the workman. During such movement, the concrete can be tamped and immediately smoothed in a single operation by a single workman.

In view of the foregoing, it is readily apparent that the structure of the present invention provides an improved vibratory tamper which affords improved control of the device by substantially eliminating the transfer of undesirable horizontal vibrations to the workman and to the trowel. portion of the device. With such arrangement, substantially all vibration developed in the drive portion of the device is concentrated for reciprocating the tamper portion of the device.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A vibratory tamper comprising a support frame; a substantially rectangular float shoe having predetermined leading and trailing portions adapted to be propelled in a predetermined substantially rectilinear path of travel, said leading portion providing a top wall section and depending spaced substantially parallel side wall sections providing lower edges with the wall sections defining a downwardly opening channel, said trailing portion providing a substantially planar surface disposed in horizontal coplanar relation with said lower edges of the wall sections and being adapted to contact concrete in a plastic state and to effect a troweling action during said rectilinear movement; manually engageable handle means rigidly upwardly extended from said frame; an elongated substantially rectangular tamper having opposite ends affording a substantially planar reticulated tamping surface; guide means integral with the frame; a cross head means mounted above said top wall section of the shoe having a central bore formed therein and a pair of elongated spaced depending connecting members symmetrically related to said bore and extended in laterally constrained longitudinal sliding relation through said guide means and through said top wall section mounting the tamper within said channel of the leading portion of the shoe in substantially parallel relation to said float surface for rectilinear reciprocating movement in a direction substantially normal to said tamping surface; power means borne by the frame; an eccentric drive member connected to said power means in driven relationship; a connecting rod having an upper end connected to said eccentric drive member and an opposite lower end of a diameter smaller than said bore in the cross head extended substantially concentrically through the bore; and a pair of resilient couplings connecting said lower opposite end of the connecting rod to said cross head means to impart said rectilinear reciprocating movement to said tamper so as to absorb vibrations originating in said eccentric drive member in a plane substantially normal to the path of reciprocating movement of the tamper.

2. The vibratory tamper of claim 1 in which said guide means includes a pair of spaced boss members on the frame having elongated bores therethrough adjacent to each end of the tamper; said cross head means comprises a pair of said cross heads and said connecting members comprise a pair of depending legs longitudinally slidable through said bores of the boss members to preclude lateral rocking of the tamper; and said resilient couplings comprising a pair of bushings disposed above and below their respective cross heads and being of a diameter larger than the diameter of the bore thorugh the cross heads, adjusting means borne by the lower end of said connecting rods adjustably to tighten the bushings against their respective cross heads so as to maintain said connecting rods in concentric relation within the bores substantially completely to isolate lateral vibrations emanating in the connecting rod from the tamper.

3. A vibratory tamper comprising a support frame; a float shoe mounted on said frame having predetermined leading and trailing portions adapted to be propelled in a predetermined substantially rectilinear path of travel, said leading portion providing a downwardly opening channel and said trailing portion providing a substantially planar surface adapted to contact concrete in a plastic state and to effect a troweling action during said rectilinear movement; manually engageable handle means rigid ly extended from said frame; a tamping member affording a substantially planar tamping surface; a support member having a bore therethrough and a pair of spaced depending legs guided by the frame mounting the tamping member within said channel of the leading portion of the shoe in substantially parallel relation to said float surface for rectilinear reciprocating movement in a direction substantially normal to said tamping surface; power means carried by the frame; reciprocating means connected to said power means in driven relationship; a connecting rod having one end connected to said reciprocating means and an opposite end extended through said bore in the support member; and resilient means connecting said opposite end of the connecting rod to said support member to impart said rectilinear reciprocating movement to said tamping element and to absorb vibrations in a plane substantially normal to the path of reciprocating movement.

References Cited by the Examiner UNITED STATES PATENTS JACOB L. NACKENOFF, Primary Examiner.

Claims

3. A VIBRATORY TAMPER COMPRISING A SUPPORT FRAME; A FLOAT SHOE MOUNTED ON SAID FRAME HAVING PREDETERMINED LEADING AND TRAILING PORTIONS ADAPTED TO BE PROPELLED IN A PREDETERMINED SUBSTANTIALLY RECTILINEAR PATH OF TRAVEL, SAID LEADING PORTION PROVIDING A DOWNWARDLY OPENING CHANNEL AND SAID TRAILING PORTION PROVIDING A SUBSTANTIALLY PLANAR SURFACE ADAPTED TO CONTACT CONCRETE IN A PLASTIC STATE AND TO EFFECT A TROWELING ACTION DURING SAID RECTILINEAR MOVEMENT; MANUALLY ENGAGEABLE HANDLE MEANS RIGIDLY EXTENDED FROM SAID FRAME; A TAMPING MEMBER AFFORDING A SUBSTANTIALLY PLANAR TAMPING SURFACE; A SUPPORT MEMBER HAVING A BORE THERETHROUGH AND A PAIR OF SPACED DEPENDING LEGS GUIDED BY THE FRAME MOUNTING THE TAMPING MEMBER WITHIN SAID CHANNEL OF THE LEADING PORTION OF THE SHOE IN SUBSTANTIALLY PARALLEL RELATION TO SAID FLOAT SURFACE FOR RECTILINEAR RECIPROCATING MOVEMENT IN A DIRECTION SUBSTANTIALLY NORMAL TO SAID TAMPING SURFACE; POWER MEANS CARRIED BY THE FRAME; RECIPROCATING MEANS CONNECTED TO SAID POWER MEANS IN DRIVEN RELATIONSHIP; A CONNECTING ROD HAVING ONE END CONNECTED TO SAID RECIPROCATING MEANS