many of the fastening , connection , processes and other means and components utilized in this invention are widely known and used in the field of the invention described , and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art , and they will not therefore be discussed in significant detail . also , any reference herein to the terms “ left ” or “ right ” are used as a matter of mere convenience , and are determined by standing at the rear of the machine facing in its normal direction of travel . furthermore , the various components shown or described herein for any specific application of this invention can be varied or altered as anticipated by this invention and the practice of a specific application of any element may already by widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail . fig1 shows a pair of conditioner rolls 10 in relative position generally as they would be in a crop conditioner . a steel ribbed roll 12 is shown intermeshing with a grooved rubber / urethane roll 14 ( only one rib 13 and one groove 15 being depicted ). roll 14 , which is preferably fixed in position , is securely attached to a framework ( not shown ) and rotates about fixed longitudinal axis corresponding to the axis of shaft 18 . roll 12 , which is usually biased and movable toward roll 14 , is movably mounted relative to the framework and is in approximate parallel alignment with roll 12 . movable roll 12 , similarly to roll 14 , rotates about the axis of shaft 16 . both rolls are generally cylindrical in shape and have end caps to enclose the interior and provide support for the rolls on the respective axises . as is known in the art , the movable roll 12 is biased toward the fixed roll 14 under a selectively variable pressure by springs or torsion bars , for example . urethane material of 80 shore a durometer or higher is preferred for improved wear and toughness . lower durometer material tends to be too soft , losing effective crushing in some crops and wearing too quickly . the grooves are preferably spiraled across the length of the roll for smooth operation . the spiral can be chevron as well as a single spiral . fig2 is an end view of one embodiment of the intermeshing rollers as contemplated by this invention . in this embodiment , steel ribbed roll 12 is mounted about shaft 16 and is intermeshing with rubber / urethane conditioning roll 14 . the grooves are either spiraled ( right and left hand ) or in a chevron pattern , similar to the pattern shown in fig2 of u . s . pat . no . 6 , 050 , 070 . two rolls are used , one generally above the other , and one of the two , either top or bottom , is made of steel . roll 14 , which contains the grooves , is made of rubber or urethane - like material 20 adhered to a tubular steel sleeve 22 by any of the processes well known in the art . steel roll 12 has a raised rib 24 arranged to intermesh with the step grooves 28 on roller 14 . the ribs 24 may in one form comprise a weld bead , however , it has been determined that a curved steel rod , welded to the smooth steel rolls is less expensive to manufacture and provides a more uniform and visually appealing rib . furthermore , the rib could be fabricated out of a wear resistant material to improve durability . the two rolls are preferably run with a precision gap therebetween depending upon the specific crop conditions encountered . five grooves and ribs have been found to be most generally effective , but this number may be anywhere in the range of 3 – 8 and provide acceptable results . the grooves and ribs are generally evenly spaced around the peripheral surface of the rollers . the gap between the two rolls can be changed to adjust intermeshing roll relationships for different crops . fig3 is a cross sectional view of another embodiment of the grooved roller and clearly illustrates the most recent , effective , and preferred design of this roll combination which incorporates a semicircular groove 26 with rounded edges in the rubber / urethane roll 14 . the rib 24 on the steel roll 12 is centered in the groove , but does not come into contact with the bottom of the groove . this minimum clearance between the bottom of the groove 26 and the tip of the rib 24 can vary , however it has been determined that minimally it should be about 30 thousandths of an inch , to prevent the complete breakage of the stems and excessive damage to the leaves of the crop material . the clearance then varies depending upon the exact shape of the groove — e . g ., note the clearance around the rib 24 in fig3 and 4 with the different groove shapes 26 and 30 . generally , the clearance away from the top of the rib is 30 thousandths of an inch greater than the clearance at the top of the rib , e . g ., if the clearance at the top of the groove is 30 thousandths , the remaining clearances is at least 60 thousandths . the grooves and ribs used in this design give a more positive feeding as the rolls rotate in the direction r , yet do not break the stalks or leaves into multiple pieces , while the smooth surfaces provide good conditioning . what these clearances do is provide a gripping of the crop material , while allowing the crop to slide and stretch within the groove without breaking . fig4 is a cross - sectional view of yet another embodiment of the grooved roller . fig4 depicts a design of this roll combination that incorporates a semi - rectangular groove 30 with rounded edges in the rubber / urethane roll 14 . the rib 24 on the steel roll 12 is centered in the groove . in operation , the ribs of the upper roll act as a feeding lug and press the crop material into the groove and against the gripper edge of the groove ( the trailing edge in the direction of rotation r of the rolls ) for positive feeding . this works well with rolls abutted for some crops , like alfalfa or grass , and with rolls precisely gapped for other crops , like cane . while the diameter of acceptable rolls can be within a wide range , a quite practical diameter has been between 9 and 10 inches . likewise , the depth of the grooves and height of the ribs can vary considerably , with 5 / 16 inch to 7 / 16 inch in height being satisfactory for the rib . these designs have been found particularly successful in oat hay . oat hay stems have hard nodes along the length thereof that trap moisture between nodes . in order to break the stems adequately between nodes , what might be considered excessive conditioning in other crops must be used . thus , it has been found that more pressure is required between the rolls — pressure provided in some machines made by new holland with an optional heavier than usual torsion bar . the combination required for this invention has proven results in that it has almost halved the field drying time required in some circumstances . it will be understood that changes in the details , materials , steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention . the foregoing description illustrates the preferred embodiment of the invention ; however , concepts , as based upon the description , may be employed in other embodiments without departing from the scope of the inventions . accordingly , the following claims are intended to protect the invention broadly as well as in the specific form shown .
a pair of conditioning rolls is disclosed that comprise one steel and one rubber / urethane roll . the steel roll has raised ribs formed thereon or attached thereto in a spiral configuration , while the rubber / urethane roll contains grooves therein that intermesh with the raised ribs during operation to grip the crop material . the smooth areas of the rolls crush the crop stems . alternative embodiments of the grooves provide the ability to work within a wide range of crops , including crops that have heretofore proven difficult to condition .