The Invention is an apparatus for training softball and baseball players in the proper technique for sliding into a base. The apparatus and method of the Invention allow a student softball or baseball player to overcome his or her fear of falling and fear of impact in a controlled, low-risk environment while learning the skills required to safely slide into a base.
In the games of baseball and softball, a properly executed slide makes it more difficult for a position player manning a base to tag a runner. Sliding into the base is a necessary skill for any accomplished softball or baseball player; however, many young players are reluctant to learn the skill due to the fear of pain and injury. Conversely, a young player may injure him- or herself by attempting to slide without instruction and without the skills to execute a slide safely. For these reasons, youth softball and baseball coaches are reluctant to train players to slide or to even set aside regular time for sliding practice, yet players are expected to slide in games when sliding situations arise. This lack of time spent sliding is in stark contrast to the many hours players routinely spend practicing hitting, throwing and catching.
In a foot-first slide, a player sprints toward the base along the baseline and assumes the ‘
The friction of the player's pants against the dirt slows the sliding player. If the player correctly gauges his or her initial speed and the rate of slowing during the slide, the player will stop while in contact with the base. If the player misjudges his or her speed, the player may stop short of the base or may slide past the base. If the player uses incorrect technique in the slide, the player may injure him or herself due to friction or impact.
Slide training apparatus are known in the art. U.S. Pat. No. 4,887,811 to Tresh issued Dec. 19, 1989, U.S. Patent Publication 2014/0051531 by Mazzocchi published Feb. 20, 2014 and the Schutt Slide-Rite 2.0 product marketed by Kranos Corporation, 710 South Industrial Drive, Litchfield, Ill. 62056 teach mats for slide training. The Schutt product is representative. The Schutt Slide-Rite 2.0 product utilizes a mat composed of fabric-covered foam to absorb the impact of a student landing on the mat. The Schutt Slide-Rite 2.0 foam is thick, at about 2.5 inches. The relatively deep penetration of the student into the Schutt foam causes substantial friction between the student and the Shutt mat, which reduces the slide of the student and may stop the slide prematurely. The thick foam is also bulky, and may present issues of storage and transportation.
The prior art does not teach the apparatus and method of the Invention.
The apparatus of the Invention is an apparatus for teaching a baseball or softball player the safe and proper technique for sliding into a base. The apparatus comprises a resilient pad and a load-spreading member. The resilient pad is composed of a resilient material, such as open cell foam. The resilient pad absorbs the impact of a softball or baseball student, either small or large, landing on the mat.
The load-spreading member spreads the force of the student landing on the mat to a larger area and volume of the resilient pad than would be the case without the load-spreading member. The nature of open cell polymer foams is that the foam experiences nearly linear strain over a range of applied stress in compression. Because of the nearly linear stress/strain relationship of the open cell foam, the student landing on the load-spreading member on the resilient pad penetrates into the open cell foam less than would be the case without the load-spreading member. Because the student does not penetrate deeply into the foam on landing, use of the load-spreading member allows the thickness of the open cell foam to be less than would be the case without the load-spreading member. The open-cell foam also can be less dense and hence lighter and less expensive than would be the case without the load-spreading member.
The load-spreading member is disposed over all or a part of the top side of the resilient pad. The load-spreading member has a length and a width and is of at least an adequate size to transfer the force of the student landing on the load-spreading member to an adequate area and volume of the open cell foam to cushion the landing of the student and to prevent the student from fully crushing the open cell foam.
The resilient pad has a pad thickness, a crushed thickness and an expanded thickness. The ‘pad thickness’ is the thickness of the resilient pad normal to the top or bottom sides of the resilient pad. The ‘crushed thickness’ is the reduced thickness of the resilient pad when a force is applied to the pad normal to the top side of the resilient pad so that the pad will no longer experience resilient deformation in response to additional force. The ‘expanded thickness’ is the thickness of the resilient pad when the pad is not subjected to a force normal to the top of the resilient pad. Both the resilient pad and the load-spreading member have a stiffness, with the stiffness of the load-spreading member being greater than the stiffness of the resilient pad. The thickness and stiffness of the load-spreading member and of the resilient pad are selected so that the force applied by the student landing on the load-spreading member will compress the resilient pad to between the expanded thickness and the crushed thickness. The student landing on the load-spreading member will not compress the resilient pad to the crushed thickness. If the student misses the load-spreading member and lands directly on the resilient pad, the student may crush the resilient pad to the crushed thickness.
The apparatus of the Invention may include a base on the top side of the mat to provide a target for the student and to allow the student to gauge whether a slide is the correct distance or is long or short. The base may be removable and repositionable, as by hook-and-loop fasteners, to allow the student to learn different aspects of sliding technique and to practice different sliding scenarios.
In a first embodiment, the load-spreading member does not cover the entire top surface of the mat and instead defines a stripe in the longitudinal direction along the center of the top side of the resilient pad. The stripe defines the path along which the student will slide. The top side of the mat may define a frame into which the load-spreading member slides to releasably attach the load-spreading member to the mat. The frame holds the periphery of the load-spreading member. The surface of the load-spreading member is exposed through the frame. A fastener retains the load-spreading member in the frame. The resilient pad may feature a fabric cover between the resilient pad and the load-spreading member and the fabric of the fabric cover may define the frame.
To use the apparatus of the first embodiment, a user places a sliding sheet on top of the load-spreading member and on the mat at the location on which the student will land. The sliding sheet is separate from the mat and may be composed of any suitable material, such as cotton or synthetic sailcloth, polar fleece, terrycloth, woven or non-woven fabric, a calendared polymer or any other suitable flexible sheet material. The purpose of the sliding sheet is to prevent abrasion injuries to the student from sliding on the resilient pad and load-spreading member and to control the friction between the sliding sheet and the load-spreading member. The sliding sheet has a first side and a second side. The sliding sheet may exhibit a single material on both the first and second sides. Alternately, the sliding sheet may be composed of two different materials that are joined, as by sewing, so that the two opposing sides exhibit the two different materials. Where the sliding sheet exhibits two different materials, the user may select the sliding friction by selecting one of the sides of the sliding sheet on which to slide.
To use the Invention, the student will run in the longitudinal direction toward the mat and assume the figure-4 position. The student will land on the sliding sheet on the load-spreading member. The vertical force of the student landing on the load-spreading member causes both the load-spreading member and the resilient pad below the load-spreading member to resiliently deform, absorbing the impact and cushioning the student. The forward momentum to the student causes the student and the sliding sheet to slide on the load-spreading member in the longitudinal direction.
If the student is inaccurate in his or her aim and lands either wholly or partially off of the load-spreading member, the student will experience high friction from the resilient pad and thus slow very quickly. The student also may fully compress the resilient pad if the weight of the student lands off of the load-spreading member, causing the student a bump his or her bottom on the surface below the resilient pad. Because of the stress and strain characteristic of the foam, the student will nonetheless impact the surface below the pad with less force than if the resilient pad were not in place. Both of these events cause the student to quickly learn the importance of an accurate takeoff and landing.
While the student is sliding, the student is tempted put to his or her hands down for balance, which is not proper technique for safety. For the first embodiment, if the student puts his or her hands down while sliding, his or her hands will contact either the resilient pad or will contact the sliding sheet on top of the resilient pad. In either event, the friction caused by the student's hands or the sliding sheet will quickly slow the student, shortening the student's slide. The student quickly learns not to put his or her hands down.
For the first embodiment, a tough and durable fabric, such as a vinyl-covered fabric, woven nylon or other fabric or solid vinyl may cover the mat, including the resilient pad. The fabric may define a frame, open to the top side of the mat, configured to receive the load-spreading member and into which the load-spreading member slides. A strip of a suitable fastener, such as hook-and-loop fastener, may retain the load-spreading member in the frame. The frame covers the periphery of the load-spreading member and protects the student from possible injury caused by an edge defect that possibly may exist on the load-spreading member. The fabric frame also protects the student from a possible pinch injury if the student manages to place a finger between the resilient pad and the load-spreading member. The load-spreading member may extend for only a portion of the length of the mat because the student will not slide the entire length of the mat.
Rather than defining a frame, the fabric may cover the entire load-spreading member so that the sliding sheet slides on the fabric rather than on the load-spreading member.
The mat may be divided into sections that are hinged and that accordion-fold from an extended condition to a folded condition. In the folded condition, the sections are in a compact suitcase-shape for ease of carrying. Hook-and-loop fasteners, snaps, straps or any other suitable mechanism may retain the sections in the folded condition. Each of the sections has a width normal to the longitudinal axis of the resilient pad. The load-spreading member may be configured to have a length equal to or less than the width of the sections so that the load-spreading member may be stored between two of the sections when the sections are in the folded condition.
Alternative avenues to protect the student from edges of the load-spreading member include selecting a material for the load-spreading member that cannot have an edge defect, such as high-density foam. A second alternative is providing a load-spreading member that will not break to define edge defects and to blunt all edges of the load spreading member to eliminate edge defects. Another alternative is to protect the edges, as by burying the edges in the open-cell foam. Burying the edges in the open cell foam can also act to control the stiffness of the load-spreading member in the longitudinal direction, reducing movement of the mat in response to the friction of a sliding student.
The resilient pad optionally may include a second, denser resilient layer below the layer of open cell foam. The denser second resilient layer is selected so that the if the student misses the load-spreading member and lands on the resilient pad, or if the student otherwise fully compresses the open cell foam layer, then the downward motion of the student will be arrested by the denser second resilient layer rather than by a hard surface on which the pad rests.
A second embodiment of the Invention may include the load-spreading member extending the entire length of the resilient pad along the longitudinal axis. The resilient pad and the load-spreading member may be covered by the durable and abrasion-resistant fabric so that the student will slide on the fabric rather than on the load-spreading member.
A third embodiment of the Invention is similar to the second embodiment except that the load-spreading member covers the entire top side of the resilient pad, from edge to edge. Providing that the load-spreading member covers the entire top side of the resilient pad means that the student will slide wherever the student lands on the sliding mat and is not limited to a stripe down the center. Covering the entire top side of the resilient pad with the load-spreading member also means that the edges of the load-spreading member are widely separated and the student is unlikely to encounter any edge defects of the load-spreading member that may exist. Covering the entire top side also improves the stability of the apparatus because the mat has even less tendency to bunch and to be pulled along behind the student as he or she slides. The tough and durable fabric layer may cover the resilient pad or both the load-spreading member and resilient pad of the third embodiment. The fabric covering of the third embodiment further separates the student from any edge defects of the load-spreading member, providing addition safety to the student.
For each of the embodiments, the mat may be hinged to allow the mat to fold from and extended position to a folded position having a compact size for storage and transportation. Three or four sections that accordion-fold are believed to be suitable. As an alternative to the single, un-hinged load-spreading member of the first embodiment, separate load spreading member portions may be attached to some or all of the folding sections. At the intersection between the adjacent sections, the downstream load-spreading member portion will be sloped to well below the elevation of the adjacent upstream load-spreading member portion so that the weight of the sliding student will pass smoothly from one section and from one load-spreading member portion to the next. The sloping downstream load-spreading member eliminates the possibility that the sliding student might run into the end of the downstream load-spreading member portion. The load-spreading member portions may not extend along all of the sections because the student will not slide for the entire length of the mat.
For each of the embodiments, the sections may be of different thicknesses. For example, a first section may be the designated landing location for the student, who will then slide across the second section to the target base located on the third (or a fourth) section. Only the resilient pad of the first section need be adequate to absorb the force of the landing student. The second, third and fourth sections need provide only minimal cushioning to the student as the student slides on those sections. As an alternative, the second section also may feature resilient pads that will absorb the force of the landing student who misses the first section while the third and fourth sections provide minimal cushioning.
For the second and third embodiments, the resilient pad and the load-spreading member are attached one to the other by any suitable mechanism, such as by an adhesive or by stitching. The load-spreading member may be retained in position on the resilient pad by the fabric covering, avoiding the use of adhesive, stitching or other attachment mechanism.
For each of the embodiments, the thickness and the stiffnes of the open cell foam in compression may be selected so that if a baseball or softball player practicing a slide were to land on the resilient pad without the load-spreading member, the player's body would compress the pores of the open cell foam completely to the crushed thickness and allow the downward motion of the player's body to be stopped by the surface underneath the open cell foam. By including the load-spreading member, each of the embodiments prevents that occurrence and transfers the force of the student's landing to an adequately large area and volume of open cell foam so that the student's downward motion is stopped by the open cell foam and not by the surface supporting the open cell foam.
For each of the embodiments, the resilient pad may include a second denser resilient layer to arrest the downward motion of the student in the event that the student, particularly a large and heavy student, fully compresses a less-dense layer during landing.
From
As noted above, the purpose of the load-spreading member 16 is to support a student landing on the load-spreading member 16 and to spread the impact of the landing student to a relatively large area of the resilient material 26. The use of the load-spreading member 16 allows use of a thinner, lighter and hence less expensive resilient material 26, such as open cell foam 28, than would otherwise be the case without the use of the load-spreading member 16. Exposure of the relatively slippery load-spreading member 16 on the top side 10 of the mat 2 also allows a lower coefficient of kinetic friction between the sliding sheet 34 and the mat 2, allowing an inexperienced student to slide more easily than would otherwise be the case.
The load-spreading member 16 is a relatively thin and relatively stiff solid polymer such as poly(methyl methacrylate), polyethylene, polypropylene, polycarbonate, polystyrene, fiber-reinforced resin, or any other suitable material that is selected to be relatively thin compared to its length and width, relatively stiff, resilient in flexure, impact resistant, and to transfer the impact load to the resilient pad 24. Corrugated plastic sheet 30 composed of polypropylene that is 3/16 inches (4 mm) in thickness and with a weight of approximately 700 grams/square meter has proven suitable in practice for the load-spreading member 16. The corrugated plastic sheet 30 features polypropylene top and bottom layers and has polypropylene webs interposed between the top and bottom layers. Suitable corrugated plastic sheets 30 are available from Boxforless.com, of 6836 Lankershim Blvd., North Hollywood, Calif. 91605.
A base 32 is disposed on the mat top side 10 at the mat second end 8. The base 32 mimics the appearance of a baseball or softball base and provides the student with a sliding target. The base 32 can be moved to different locations on the mat top side 10 at the mat second end 8 to allow the student to practice different sliding scenarios. The base 32 is releasably attachable to the mat top side 10 by any suitable mechanism, such as hook-and-loop fasteners.
To use the Invention, a student runs in the longitudinal direction 44, shown by
Where the sliding sheet has two different materials 38, 42, the first side 36 of the sliding sheet 34 has a first material 38 that is relatively slippery and that results in a relatively low coefficient of kinetic friction when a student is on the sheet 34 and the first side 36 of the sheet 34 is sliding on the load-spreading member 16. The relatively slippery material of the first side 36 of the sliding sheet 34 allows the student to slide easily on the mat 2.
The second side 40 of the sliding sheet 34 exhibits a second material 42 resulting in a higher coefficient of kinetic friction when the student is on the sliding sheet 34 and the second side 40 of the sliding sheet 34 is sliding on the load-spreading member 16. The second material 42 is selected to approximate the higher friction experienced by the student sliding into an actual base on the dirt of an actual baseball or softball diamond
A sliding sheet 34 with the first side 36 composed of polyester polar fleece and the second side 40 composed of cotton terrycloth has proven suitable in practice where the load-spreading member 16 is composed of corrugated plastic 30 as described above on a mat 2 having a resilient pad 24 of open cell foam 28 that is 1.5 inches thick. The polyester polar fleece, a soft-napped insulating fabric, provides a relatively low coefficient of kinetic friction. The cotton terrycloth provides a relatively high coefficient of kinetic friction. For a two-sided sliding sheet 34, a user can select a higher or lower coefficient of kinetic friction by selecting which side 36, 40 of the sliding sheet 34 is against the load-spreading member 16.
The Inventor conducted experiments to determine appropriate coefficients of kinetic friction between the sliding sheet 34 and the mat 2. The inventor prepared a test mat having a resilient pad composed of open cell foam that is 1.5 inches thick and enclosed in a cover composed of an abrasion-resistant vinyl-covered fabric of 18 ounces per square yard in weight. The Inventor secured a load-spreading member 16 to the mat 2. The load-spreading member 16 was composed of 4 mm thick corrugated plastic 30, as described above. The Inventor determined that the combination of load-spreading member 16 and mat 2 to be suitable for the purpose and to adequately cushion students of different weights landing on the load-spreading member 16 and mat 2. The Inventor secured the load-spreading member 34 of corrugated plastic 30 to the mat 2 using a frame 14, as described above. After experimentation, the Inventor determined that a sliding sheet 34 exhibiting a first side 36 of polar polyester polar fleece provided a suitable low sliding friction to allow an inexperienced student to easily slide while learning sliding technique. After experimentation, the Inventor determined that a sliding sheet 34 exhibiting a second side 40 of cotton terrycloth exhibited an adequately high sliding friction to adequately mimic the friction that a baseball or softball player would experience when sliding into an actual base in the dirt on an actual baseball or softball diamond. The Inventor then derived the coefficients of kinetic friction for each of those combinations. The following table presents the results of that derivation:
Where:
a) the subject identifies the human test subject,
b) the weight is the measured weight of the human test subject,
c) the force (N) is the measured force in newtons required to maintain sliding movement of the sliding sheet 34 along the load-spreading member 16 on the mat 2 with the human test subject on the sliding sheet 34,
d) the force (lbs.) is the force (N) converted to pounds,
e) the sliding sheet 34 material 38, 42 is the material in sliding engagement with the load spreading member 16. The first material 38 is polyester polar fleece. The second material 42 is cotton terrycloth.
e) μ is the coefficient of kinetic friction and in this instance is the dimensionless ratio of the force (lbs.) to the weight (lbs.).
From these data, the Inventor concludes that an acceptable value for the coefficient of kinetic friction between the low-friction first material 38 and the mat 2 is less than or equal to 0.39. Any combination of materials and configurations of materials that results in a coefficient of kinetic friction of less than or equal to 0.39 will allow an inexperienced student to easily and safely slide while learning proper technique. The Inventor also concludes that from these data an acceptable value for the coefficient of kinetic friction between the high-friction second material 42 and the mat is greater than 0.39. Any combination of materials and configurations of materials that results in a coefficient of kinetic friction of greater than 0.39 will adequately approximate the friction that the student will experience when sliding into an actual base on an actual baseball or softball diamond.
Any configuration for the sliding sheet 34, mat 2, abrasion-resistant fabric 18, load-spreading member 16, resilient pad 24, and thickness of the resilient pad 24, that result in coefficients of sliding friction within the indicated ranges are contemplated by the Invention.
For the second and third embodiments, the load-spreading member 16 is in one or more portions that cooperate to define the entire load-spreading member 16 when the sections 4 of the mat 2 are unfolded. As a result, the portions of the load-spreading member 16 stay with the sections 4 with which they are associated. FIGS. 15, 16 and 17 illustrate configurations of the load-spreading member 16 to reduce the likelihood that a student may come in contact with an imperfection in the edge of a load-spreading member 16 when sliding on the mat 2.
In the second and third embodiments of
The following is a list of the numbered elements.
Number | Name | Date | Kind |
---|---|---|---|
4887811 | Tresh | Dec 1989 | A |
5114387 | Keppler | May 1992 | A |
5246401 | Boatwright | Sep 1993 | A |
5326338 | Makous | Jul 1994 | A |
5352165 | Koblick | Oct 1994 | A |
D355001 | Koblick | Jan 1995 | S |
5813925 | Lewy | Sep 1998 | A |
6142879 | Phillips | Nov 2000 | A |
6692257 | Branum et al. | Feb 2004 | B1 |
6984195 | Phillips | Jan 2006 | B1 |
7001282 | Jennings | Feb 2006 | B1 |
7309302 | Phillips | Dec 2007 | B1 |
10076695 | Simon | Sep 2018 | B1 |
20140051531 | Mazzocchi | Feb 2014 | A1 |
Entry |
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Amazon.com Schutt Sports Slide Rite advertisement, accessed Dec. 13, 2017, https://www.amazon.com/Schutt-12911240-Sports-Slide-Rite/dp/B00120SE28, hard copy attached. |