Abstract:
The present invention provides a compressible seal for installation in joints in concrete pavement, the machine for installing the seal and the method of installation. The seal is a preformed, closed cell, elastomeric cylinder or rope. The seal defines a round cross section in its relaxed, i.e., uncompressed, state somewhat larger than the joint into which it will be installed. The installation machine is a wheeled, hand powered device having a first guide wheel which is received within the joint, an aligned installation wheel which installs the seal in the joint, a second guide wheel which ensures that the seal is at the proper depth in the joint and a pair of contra-circulating belts which feed the seal to the installation wheel.

Description:
FIELD 
       [0001]    The present disclosure relates to a compressible seal for installation in pavement and more particularly a compressible seal for installation in joints in concrete pavement, the machine for installing the seal and the method of installation. 
       BACKGROUND 
       [0002]    The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
         [0003]    Installations of concrete pavement including both those with a single large dimension such as driveways and roads and those with two large dimensions such as parking lots and airport aprons expand and contract with the ambient temperature. Such expansion or contraction will frequently result in cracking of the concrete which, without exception, shortens the service life of the concrete. In geographic regions subject to repeated freezing and thawing, the service life of cracked concrete may be dramatically shortened. 
         [0004]    An accepted approach to this problem is to saw kerfs or grooves in the concrete after it has been poured but before it is cured. These kerfs or grooves are generally referred to in the trade as joints and expansion or contraction joints. Because the concrete is generally thinnest at the sawn joints, they act as uniform, linear crack generation sites that cause the concrete to crack in a controlled manner and reduce or eliminate random crazing and cracking. However, the joints themselves need to be protected so that non-compressible materials, e.g., small stones and foreign matter, and water do not fill them. Because these joints are both linear and made during the installation process, they may be, and typically are, readily filled with tar to avoid the harmful effects of materials trapped in the joint and water undergoing the freeze/thaw cycle. 
         [0005]    The tar, itself, however, can be adversely affected by the freeze/thaw cycle. For example, if water collects in the joint below the tar, a freeze cycle will slightly raise the tar and repeated freeze/thaw cycles will force the tar out of the joint. Traffic will then wear away the protruding tar and a small problem may quickly become prematurely deteriorating pavement. Additionally, tar tends to become brittle after two to three years of service. It will thus compress in the winter but fail to expand in the summer, thereby allowing material and water to enter and occupy the joint. 
         [0006]    Furthermore, tar as well as many other liquid sealants, should not be installed when temperatures are below 45° F. (7° C.) or when moisture is present. This limits the conditions during which such sealants can be installed which may delay completion of an installation or repair project. Finally, many sealants put a joint in tension when the concrete contracts in cold temperatures. This tension can increase the rate at which the concrete deteriorates. 
         [0007]    From the foregoing, it can be appreciated that improvements to seals for joints or grooves in concrete slabs would be desirable. 
       SUMMARY 
       [0008]    The present invention provides a compressible seal for installation in joints in concrete pavement, the machine for installing the seal and the method of installation. The seal is a preformed, cylindrical, closed cell, elastomer. The seal preferably defines a round cross section with a diameter in its relaxed, i.e., uncompressed, state approximately 1.75 times and preferably between about 1.6 and 1.9 times greater than the width of the joint into which it will be installed. The installation machine is a wheeled, hand powered device having a pair of guide wheels which are received within the joint, an aligned installation wheel which installs the seal at the proper depth in the joint and a pair of contra-circulating belts that feed the seal to the installation wheel. The seal of the present invention will prevent concrete pavement from deteriorating prematurely by preventing water and debris from entering and occupying the sawn expansion joint. 
         [0009]    Thus it is an object of the present invention to provide a seal for installation in sawn expansion joints in concrete slabs. 
         [0010]    It is a further object of the present invention to provide a seal for expansion joints in concrete slabs which extends the life of such slabs. 
         [0011]    It is a still further object of the present invention to provide a seal for expansion joints in concrete slabs which prevents entry and accumulation of water and non-compressible material in such joints. 
         [0012]    It is a still further object of the present invention to provide a machine for installing a compressible seal in an expansion joint in a concrete slab. 
         [0013]    It is a still further object of the present invention to provide a hand powered machine for installing compressible seals in expansion joints in concrete slabs. 
         [0014]    It is a still further object of the present invention to provide a method of installing compressible seals in expansion joints in concrete slabs. 
         [0015]    It is a still further object of the present invention to provide a method of installing a compressible seal in an expansion joint of a concrete slab with a hand powered machine. 
         [0016]    Further objects, advantages and areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0017]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
           [0018]      FIG. 1  is an enlarged, perspective view of a pavement seal according to the present invention; 
           [0019]      FIG. 2  is a fragmentary, sectional view of a sawn joint in concrete pavement which illustrates the initial installation steps according to the present invention; 
           [0020]      FIG. 3  is a fragmentary, sectional view of a pavement seal installed in a sawn joint in concrete pavement which illustrates the final installation steps according to the present invention; 
           [0021]      FIG. 4  is a perspective view of a machine according to the present invention for installing pavement seal; 
           [0022]      FIG. 5  is an exploded perspective view of a machine according to the present invention for installing pavement seal; and 
           [0023]      FIG. 6  is a bottom view of a machine according to the present invention for installing pavement seal. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
         [0025]    With reference to  FIGS. 1 and 2 , a pavement seal according to the present invention is illustrated and generally designated by the reference number  10 . The pavement seal  10  is an aerated elastomer foam having closed cells  11  and a smooth, i.e. non-perforated, and therefore fluid impervious outer skin. The pavement seal  10  preferably defines a round cross section with a nominal diameter, in its relaxed, i.e., uncompressed, state of approximately 0.437 inches+0.0625 inches−0.00 inches (11.1 mm+1.59 mm−0.00 mm). Other multi-sided, for example, six, eight, ten or twelve sided polygonal configurations may be utilized and are within the purview of this invention. This diameter is intended for installation in a standard sawn joint, kerf, channel or groove  12  in concrete pavement  14  having a nominal width of 0.25 inches (6.35 mm). Thus, the diameter of the seal  10  is approximately 1.75 times the width of the joint or groove  12  or, stated inversely, the width of the joint or groove is approximately 57% of the diameter of the pavement seal  10 . This size relationship has been found to provide excellent seal performance in view of the expansion and contraction of the pavement  14  during seasonal temperature changes. 
         [0026]    A joint or groove  12  having a sawn width of 0.25 inches may typically open to a maximum width of 0.345 inches (8.76 mm) and close to a minimum width of 0.165 inches (4.19 mm) due to thermal expansion and contraction of the concrete pavement  14 . Ideally, the width of the joint or groove  12  will be approximately 57% of the uncompressed diameter of the pavement seal  10 ; preferably, the width of the joint or groove  12  will be in the range of from 52% to 62% of the uncompressed diameter of the pavement seal  10  and the width of the joint or groove  12  in a range of 45% to 70% of the uncompressed diameter of the pavement seal  10  is functional. It will be appreciated that smaller and larger diameter seals  10  may be utilized with correspondingly narrower and wider joints or grooves  12  if the ideal 57% relationship, or the preferred or functional ranges recited directly above, are adhered to. For example, a sawn joint or groove  12  having a width of 0.375 inches (9.52 mm) would ideally receive a seal  10  having an uncompressed diameter of approximately 0.655 inches (16.70 mm) 
         [0027]    The pavement seal  10  is a preformed cylinder of indefinite length. The pavement seal  10 , as noted, includes entrained air in closed cells  11 . While polychloroprene compounds have been found to provide good performance, a selection of elastomers, including polychloroprene, styrene butadiene, acrylonitrile butadiene, polyethylene, polyvinyl chloride, ethylene propylene diene and blends of these materials are also suitable. The pavement seal  10  preferably has a compression deflection, i.e., spring, rate of approximately 2 pounds per inch at 15% compression, a specific gravity of 0.6±0.1 and a density of 37.44 pounds per cubic foot ±3.74. The pavement seal  10  preferably exhibits a Shore A durometer measurement of 25±5. 
         [0028]    The pavement seal  10  according to the present invention is rugged, exhibiting a breaking strength of approximately 200 p.s.i. (1.4 mPa) with an elongation at break of 150%. It will be appreciated that the pavement seal  10  may be manufactured, typically by an extrusion process, in continuous lengths which are cut into pieces several hundred feet in length for storage and shipment on spools and then cut to desired lengths at the installation site as will be described in more detail below. 
         [0029]    Referring now to  FIGS. 4 and 5 , a pavement seal installation machine is illustrated and designated by the reference number  20 . The pavement seal installation machine  20  includes a rectangular lower frame assembly  22  typically and preferably fabricated of welded steel or aluminum box beams. The rectangular lower frame assembly  22  includes a front transverse beam  24 , a rear transverse beam  26 , a right side beam  28  and a left side beam  32 . Received within four blind sockets  34  mounted on the tops of the right side beam  28  and the left side beam  32  and releasably secured by clevis pins  36  is an upper, tubular frame assembly  40 . The tubular frame assembly  40  may be fabricated of a plurality of straight tubular sections  42  and right angle end fittings  44  or it may include a pair of U-shaped hoops each formed from a single piece of tubing. 
         [0030]    Extending between the upright tubular sections  42  at the front of the machine  20  is a horizontal beam or tube  46  which pivotally receives and supports a T-bar handle  48 . A pair of adjustable stops  50  may be moved vertically along the front upright tubular sections  42  and secured thereto to set the height of the horizontal tube  46  and the T-bar handle  48 . Extending between the upright tubular sections  42  at the back or rear of the machine  20  is a rectangular panel  52  which locates and supports a pivotable caster  54  on its outside face. The rectangular panel  52  is preferably located to provide a stop for the T-bar handle  48  when it is in a stowed position as illustrated in  FIG. 4 . So stowed, the T-bar handle  48  is not only readily accessible but it is also maintained in a position away from the operating mechanism of the machine  20 . 
         [0031]    Positioned within the lower frame assembly  22  and capable of both vertical motion and front to back motion, that is, motion parallel to the right and left side beams  28  and  32 , is a sub-frame or chassis  60 . The chassis  60  is coupled to the lower frame assembly  22  by a right adjustment assembly  62 A and a left adjustment assembly  62 B. Since the adjustment assemblies  62 A and  62 B are identical except for their mirror image construction and arrangement, only the right adjustment assembly  62 A will be described. 
         [0032]    The right adjustment assembly  62 A includes a narrow, L-shaped bracket  64  secured to and extending upwardly from the right side beam  28 . The narrow, L-shaped bracket  64  includes a threaded opening  66  which receives a complementarily threaded shaft  68  having a hand or finger engageable handle or knob  70 . At the opposite end of the threaded shaft  68  and secured thereto is a chain drive sprocket  72 . The chain drive sprocket  72  receives and drives a chain  74  that engages and drives a first, driven chain sprocket  76  and a second, driven chain sprocket  78 . The first, driven chain sprocket  76  rotates on a first threaded rod  82  and the second, driven chain sprocket  78  rotates on a second threaded rod  84 . The threaded rods  82  and  84  are received within complementarily threaded stationary nuts  86  or similar threaded components which are secured to the right side beam  28 . Openings (not illustrated) in the top of the right side beam  28  aligned with the stationary nuts  86  allow the threaded rods  82  and  84  to extend into the right side beam  28 . Resting upon the upper faces of the first and second driven chain sprockets  76  and  78  is a large, L-shaped bracket  90 A which extends upwardly from the chassis  60 . The large, L-shaped bracket  90 A defines a pair of elongate slots  92  which receive the respective pair of threaded rods  82  and  84 . Disposed on each of the threaded rods  82  and  84  above the upper surface of the large, L-shaped bracket  90 A is a washer  94  and a wing nut  96 . 
         [0033]    To adjust the front to rear position of the chassis  60  relative to the lower frame assembly  22 , the wing nuts  96  of both the right adjustment assembly  62 A and the left adjustment assembly  62 B are loosened and the chassis  60  is moved as necessary and the wing nuts  96  are then tightened. To adjust the height of the chassis  60  relative to the lower frame assembly  22 , the wing nuts  96  of both the right adjustment assembly  62 A and the left adjustment assembly  62 B are loosened and the handles or knobs  70  of the adjustment assemblies  62 A and  62 B are rotated, clockwise to lower the chassis  60  or counter-clockwise to raise the chassis  60 . When the chassis  60  has reached the desired height relative to the lower frame assembly  22 , the wing nuts  96  are tightened. It will be appreciated that in addition to providing height adjustment, the threaded shaft  68 , the chain drive sprocket  72 , the chain  74 , the first, driven chain sprocket  76 , the second, driven chain sprocket  78  and the threaded rods  82  and  84  maintain the chain  74  in a horizontal plane during height adjustment which obviates binding and chain misalignment. 
         [0034]    The sub-frame or chassis  60  includes the right and left large, L-shaped brackets  90 A and  90 B which are connected by a transverse U-shaped strap  102 . Also extending between the large, L-shaped brackets  90 A and  90 B is a rotatable shaft  104  having ends which are received within a pair of bearing assemblies  106 . An installation wheel  108  having a plurality of teeth  110  disposed about its periphery is secured to the middle of the shaft  104  for rotation therewith and a driven chain sprocket  112  is secured to the rotatable shaft  104  adjacent one of the bearing assemblies  106 . 
         [0035]    At the front of the lower frame assembly  22  is disposed a front guide assembly  120 . The front guide assembly  120  includes a forwardly and downwardly extending bar or arm  122  which is secured to the inside face of the right side beam  28 . At the forward end of the bar or arm  122  is a transversely oriented shaft  124  which extends slightly beyond the middle of the lower frame assembly  22 . On the shaft  124  at the transverse center of the lower frame assembly  22  is a first or forward freely rotatable guide wheel  126 . 
         [0036]    At the front or forward end of the lower frame assembly  22 , in the right side beam  28  and the left side beam  32 , are a pair of aligned bearings  128  which receive a front drive axle  130 . Secured to opposite ends of the front drive axle  130  are a pair of front or drive wheels  132 . Also secured to and rotating with the front drive axle  130  is a first chain drive sprocket  134  which engages and drives a first chain  136 . The first chain  136  engages and drives a first idler sprocket  138 . The first idler sprocket  138  is secured to a stub shaft  142  which is received within a vertically moveable bushing  144 . The vertical position of the bushing  144  and thus of the stub shaft  142  is adjustable by a threaded shaft  146  which may be fixed in place in an elongate slot  148  in a vertical mounting bracket  152  by a jam nut  154 . 
         [0037]    Secured to the stub shaft  142  on the opposite side of the vertical mounting bracket  152  is a second idler sprocket  156  which engages and drives a second chain  158 . The second chain  158  engages and drives the driven chain sprocket  112  on the shaft  104 . It will therefore be appreciated that motion of the pavement seal installation machine  20  along a surface will rotate the pair of front or drive wheels  132  which will rotate the front drive axle  130  and the first chain drive sprocket  134 . In turn, the first drive chain  136  and the second drive chain  158  will circulate, rotating the driven chain sprocket  112  and the toothed installation wheel  108  on the shaft  104 . The diameters of the front or drive wheels  132 , the chain sprockets  134 ,  138 ,  156  and  112  and the installation wheel  108  are such that the surface speed of the installation wheel  108  is slightly faster than the surface speed of the front or drive wheels  132 . 
         [0038]    Referring now to  FIGS. 5 and 6 , secured to the front transverse beam  24  by any suitable means such as a threaded stud are a pair of right and left speed increasing gear boxes  160 A and  160 B. The speed increasing gear boxes  160 A and  160 B preferably provide a drive ratio of 2 to 3, that is, two turns at the input result in three turns at the output. It should be understood that this ratio may be adjusted up or down to accommodate other variations in the installation machine  20 . The right and left gear boxes  160 A and  160 B are coupled to and driven by the front drive axle  130 . The gear boxes  160 A and  160 B are opposite in sense. As viewed in  FIG. 5 , with clockwise (forward) rotation of the front wheels  132  and the front drive axle  130 , the output of the right gear box  160 A is counter-clockwise when viewed from above and the output of the left gear box  160 B is clockwise when viewed from above. 
         [0039]    The outputs of the gear boxes  160 A and  160 B are provided to right and left gears or cogged wheels  162 A and  162 B, respectively, which engage a respective pair of right and left timing belts  164 A and  164 B. The right timing belt  164 A engages and circulates counter-clockwise about a right, first idler wheel  166 A and a right, second, equal diameter idler wheel  168 A. The right, first idler wheel  166 A and the right, second idler wheel  168 A are freely rotatably disposed on sleeve bearings and stub shafts  170 A secured to a right U-shaped plate  172 A which, in turn, is attached to the right L-shaped bracket  90 A through an intermediate member  174 A by suitable fasteners. 
         [0040]    The left timing belt  164 B engages and circulates clockwise about a left, first idler wheel  166 B and a left, second, equal diameter idler wheel  168 B. The left, first idler wheel  166 B and the left, second idler wheel  168 B are freely rotatably disposed on sleeve bearings and stub shafts  170 B secured to a left U-shaped plate  172 B which, in turn, is attached to the left L-shaped bracket  90 B through an intermediate member  174 B by suitable fasteners. The opposed surfaces of the right timing belt  164 A and the left timing belt  164 B are spaced apart a distance which is greater than the thickness of the toothed installation wheel  108  to allow it free motion therebetween but less than the diameter of the pavement seal  10  so that they engage and compress it. 
         [0041]    The opposed rotation and travel of the timing belts  164 A and  164 B and their spacing at the middle of the machine  20  draws the pavement seal  10  (illustrated in  FIG. 1 ) through the machine  20  as will be more fully described below. The drive ratios from the front drive wheels  132 , through the gear boxes  160 A and  160 B and through the cogged wheels  162 A and  162 B to the timing belts  164 A and  164 B are such that the surface speed of the front drive wheels  132  is the same as the surface speed of the timing belts  164 A and  164 B. Accordingly, the pavement seal  10  is drawn into the installation machine  20  and fed to the toothed installation wheel  108  without either axial stretching or compression. 
         [0042]    On the outside faces of the right side beam  28  and the left side beam  32  are mounted a pair of rear wheels  176 . The rear wheels  176  are rotatably disposed upon stub shafts or axles  178  which are secured to the respective beams  28  and  32 . Disposed in the middle of the rear transverse beam  26  in alignment with the toothed installation wheel  108  and the front rotatable guide wheel  126  is a rear guide wheel  180  rotatably mounted in a clevis  182 . It will be appreciated that the front rotatable guide wheel  126 , the toothed installation wheel  108  and the rear rotatable guide wheel  180  all cooperate to maintain the installation machine  20  in alignment with a joint or groove  12  in the concrete pavement  14  to facilitate proper and efficient installation. Furthermore, the rear guide wheel  180  sets the seal  10  to the final desired depth in the joint or groove  12 . 
         [0043]    The installation process will now be described in connection with  FIGS. 2 ,  3  and  4 . Joints or grooves  12  are cut by a saw (not illustrated) in the concrete pavement  14 . The joints or grooves  12  are cut to a minimum of 25% of the thickness of the concrete pavement  14  and preferably to a depth of 33% of the thickness. After the necessary joints or grooves  12  have been cut in the pavement  14  and any debris has been blown out of the joints or grooves  12  with compressed air from an air compressor or pressurized water from a power washer through, for example, a nozzle  16 , a length of the pavement seal  10  according to the present invention is laid along the full length of the joint or groove  12 . 
         [0044]    Next, a lubricating, soapy solution of, for example, undiluted liquid hand dish washing soap or vegetable oil soap is applied by a spray head  18  to the pavement seal  10  or the walls of the joint or groove  12  immediately prior to installation of the seal  10 . Then, the front rotatable guide wheel  126 , the toothed installation wheel  108  and the rear rotatable guide wheel  180  are placed or located in the joint or groove  12  with the front guide wheel  126  toward the direction of installation and travel. The pavement seal  10  is then inserted between the timing belts  164 A and  164 B and the installation machine  20  is moved by hand along the joint or groove  12 . The toothed installation wheel  108  rotates and installs the pavement seal  10  to the proper depth of between 0.125 inches (3.17 mm) and 0.50 inches (12.7 mm) in the joint or groove  12 . It is highly desirable that the pavement seal  10  experiences no more than approximately 4% stretch or elongation during the installation process and preferably less. 
         [0045]    As stated, the pavement seal  10  should be installed with its upper surface between about 0.125 inches (3.17 mm) and 0.50 inches (12.7 mm) below the surface of the concrete pavement  14 . To achieve this preferred depth of installation, it may be necessary to adjust the height of the toothed installation wheel  108  and the second guide wheel  180  relative to the top surface of the pavement  14 , that is, the depth of penetration of the toothed installation wheel  108  and the second guide wheel  180  into the joint or groove  12 . The toothed installation wheel  108  is adjusted by using the right and left adjustment assemblies  62 A and  62 B, as described above. The height of the second guide wheel  180  is adjusted by repositioning the clevis  182 . 
         [0046]    As noted above, pavement seals having both larger and smaller diameters than the diameter of the pavement seal  10  recited herein for correspondingly larger and smaller joints or grooves are within the purview of the present invention. Preferably, the width of the joint or groove into which the pavement seal will be installed is approximately 57% of the diameter of the pavement seal in its uncompressed (uninstalled) state. However, as noted above, the pavement seal may be installed in a joint or groove  12  having a width a little as 45% to as much as 70% of the uncompressed diameter of the pavement seal with acceptable results. 
         [0047]    Before and after installation of the pavement seal  10 , the installation machine  20  is readily moved about by tipping it onto the two rear wheels  176  (which extend beyond the ends of the side beams  28  and  32 ) and the caster  54 . The T-bar handle  48  may then also be utilized to conveniently maneuver the installation machine  20 . So disposed, the likelihood of damage to the guide wheels  126  and  180  and the toothed installation wheel  108  is minimized. Moreover, if care is taken to tip the installation machine  20  upright over the joint or groove  12  such that the guide wheels  126  and  180  and the toothed installation wheel  108  are received within the joint or groove  12 , little or no adjustment or resetting of the adjustment assemblies  62 A and  62 B should be necessary and the likelihood of damage to the wheels  108 ,  126  and  180  is further reduced. 
         [0048]    It should be appreciated that in addition to facilitating height adjustment of the chassis  60  relative to the frame  22 , the front to back adjustment also provided by the adjustment assemblies  62 A and  62 B facilitates tightening, loosening and replacement of the timing belts  164 A and  164 B. 
         [0049]    The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from either the spirit or the scope of the invention or the following claims.