Road Rash Protective Gear

En1000: Projects in Engineering Design 

 

Project Summary:

 

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Intro:

    High velocity sports like biking, rollerblading, skateboarding and parkour carry the inherent danger of falling, usually on hard abrasive surfaces like concrete or asphalt. The human body was not designed to take a sliding fall at 20+ mph;  bones can usually take the vertical impact without serious damage, but skin damage is a virtual guarantee.

 

There are countless companies that produce protective equipment for high velocity sports in the form of helmets, elbow pads, knee pads, etc. and their products effectively fulfill their intended purpose.

 

 

Well protected dudes. Source: http://www.ci.cerritos.ca.us/cityserv/recreation/attire.html	Unprotected Clown. Source: http://upload.wikimedia.org/wikipedia/commons/1/1f/Skaters_6.jpg

 

What I propose to do is create a set of pads that will not only protect you from a fall at speed, but also be a functional piece of equipment for sports. I intend to create pads that allow the wearer to slide for extended distances in contact with the ground, rather than come to an abrupt, tumbling stop. I envision this product allowing people to perform maneuvers like baseball slides on asphalt without injury. As of the current moment, I am planning on creating elbow, hip, and knee pads for this purpose (Three points of contact for stability). 

 

The people who will benefit from this solution are skating and parkour enthusiasts. This product will allow for new forms of movement that were previously impossible using current off-the-shelf products.

 

Background:

 

Elbow and knee pads exist for almost every "dangerous" activity, and some companies even create entire suits of "armor" for extreme sports, one such company being the Dainese company. (www.dainese.com)

 

A more recent development is the "sliding glove" for skateboarding and longboarding enthusiasts. Sliding gloves often consist of a glove with a low friction plastic "puck" velcroed to the palm and sometimes fingers of the glove. It appears that other sliding pads exist, but I haven't been able to find a specific product from google searches. Here is a youtube video showing the use of sliding gloves, from the company "Loaded".

 

 

There is a one-man spectacle that has taken the idea of sliding to its logical extremity: Jean-Yves Blondeau a.k.a. Rollerman. Here's a South Korean commercial which features Blondeau. If you're interested, there are plenty of videos on his youtube channel "buggyrollin", including videos in which he outraces motorcycles if you're into that stuff...

 

 

 

 

 

 

 

Intellectual Property:

 

Patent number: 5373584

Filing date: Feb 19, 1993

Issue date: Dec 20, 1994

Inventors: Charles A. Parcells, III

Primary Examiner: Michael A. Neas

 

Sliding accessories to permit in-line roller skating maneuvers equivalent to ice skating maneuvers

Abstract

To provide effective and protective sliding means for in-line roller skating, ultra-high molecular weight polyethylene (UHMW) plates are detachably fastened to the protective outerclothes and gloves of the user. Hook and loop fasteners are used in a manner that permits the UHMW plates to articulate on the fastening as the plate slides or skids on the pavement and the user's position changes during the slide. With the hook and loop fastening, excessive shear stress or pulling, from contact with an obstruction, permits the UHMW plate to separate before these stresses damage the skid plate, the hook and loop fastening, the adhesive bonds or the underlying protective clothing. The result is a slide or sliding fall as on ice in ice skating and various fall and slide maneuvers of the ice skater are made practical for the in-line roller skater on pavement.

 

 

Patent number: 5926857

Filing date: Nov 24, 1997

Issue date: Jul 27, 1999

Inventor: Jean-Yves Blondeau

Primary Examiners: Larry D. Worrell, Jr.

 

Armor with rollers

Abstract

An armor with rollers is provided that enables a user to move in all positions by rolling on a hard and smooth surface while constantly varying his bearing points on the ground. The armor includes a pair of gauntlets extending from beyond the user's hand to the user's elbow and having rollers at both ends thereof. The armor also includes a pair of rigid leg pads having rollers near the user's knees.

 

 

Patent number: 6510560

Filing date: Oct 8, 1999

Issue date: Jan 28, 2003

Inventor: Adam Ugolnik

Primary Examiner: Gloria M. Hale

Attorney: Tony A. Gayoso

Application number: 9/414,158

 

Roller-suit and apparel

Abstract

A body roller suit (1) containing a plurality of rollers (20) wherein a wearer's body can roll along the ground or other surface. More particularly, the body roller suit contains a distribution of rollers (20) such that a wearer lying on a surface would be supported entirely by rollers (20). Additional apparel and equipment can be worn for safety and control while using the body roller suit (1). The invention further relates to methods for producing a roller suit (1).

 

Patent number: 5870774

Filing date: Aug 29, 1997

Issue date: Feb 16, 1999

Inventor: Mark P. Legenstein

Primary Examiners: Larry D. Worell, Jr.

 

Rolling knee pad

Abstract

A roller knee pad having a hard shell supported by a plurality of swiveling casters. The inside of the hard shell is lined with a cushioning material to absorb shock when kneeling and to cushion against minor shape disparities between the wearers knees and the inside of the hard shell. A plate is attached to the exterior portion of the hard shell to provide mounting locations for a plurality of casters. The casters are capable of swiveling through a 360 degree range. Ideally three casters are used to support the knee pad allowing the pad to be self supporting and allowing the wearer to easily balance on the knee pad without exerting undue pressure on his/her toes. A rolling knee pad is strapped to each of the wearers knees allowing the user to kneel without concern about placement of the knee pad. Once the knee pads are engaged to the floor surface, the wearer may move laterally in any direction while still on his/her knees. If desired, the user may rise, walk to another location and then re-kneel without having to engage one hand with carrying the knee pads. Both hands are thus free to carry tools and materials when rising and kneeling on the invention.

 

 

My Proposed Solution:

 

Although sliding gloves and pads already exist for skateboarders, these pads have a few drawbacks.

1. They wear down unevenly, requiring you to detach and rotate the pads periodically.

2. The high friction induced by sliding generates ample amounts of heat, sometimes burning and/or melting sections of the pads, and also transferring the heat to your body if you don't have ample insulation.

3. These gloves and pads are not particularly versatile- they can only be used on relatively hard, smooth surfaces.

4. Load Shock resistance was not a major concern in the design of these pads, if you hit the ground hard, you will still get hurt.

 

Prior art, as shown in the Intellectual property section, address many of the concerns I propose to tackle. Patent number: 5373584 "Sliding accesories to permit in-line roller skating ... "is the most similar to the field of my invention, but it employs abrasion pads to mitigate impact. The other patents describe rolling suits or pads, but all are ridiculously bulky, heavy, and seem like they would be a pain in the butt to wear around for regular activity. They would be entirely inappropriate for a sport like parkour, for example.

 

My proposed solution is to create a set of pads that slide on ball transfers (like in Patent number: 6510560 Roller-suit and apparel) , and have a spring cushioning system to reduce the force of impact with a surface. The use of ball transfers will virtually eliminate asymmetric wear, as the balls freely rotate within their sockets. Friction is also greatly reduced since the pads will roll rather than slide. The rolling aspect will also allow the pads to be used on stickier surfaces like rubber (a relatively common roofing material). The cantilevered spring system will allow the user to engage in more dynamic movements, safely mitigating reasonable shock loads on the body. See diagrams below for a basic idea.

 

 

Requirements:

Here are my project

1. Requirements
   1. Must be able to absorb repeated impact without loss of function (150 lb. weight dropped from four feet 20x)
   2. Must allow user to slide at least 20 feet on flat asphalt from a sprint (repeat 5x) without loss of skin (obviously).
   3. Must weigh under 2 lbs. per unit.
   4. Should have some sort of braking system to increase friction.
   5. Should be under 1 lb.
   6. Should be able to repeat sliding at least 50x without having to replace parts.
2. Constraints
   1. Total materials cost per pad should be under $50
3. Evaluation Criteria
   1. Indoor test (smooth surfaces)
   2. Outdoor test (rough surfaces)

 

 

First Prototype:

 

Brainstorms:

Here are the ideas I've come up with to build and test my solutions:

First Prototype: (here are my pictures, videos, schematics, drawings, brainstorm notes, parts list, and gatorade receipts)

 

Parts List:

 

McMaster Catalog:

 

1. 6421K66

Press-Fit Ball Transfer Standard, 5/8" Steel Ball, Steel Housing, 84# Cap

In stock at $8.83 Each

Quantity: 3

2. 6421K67

Press-Fit Ball Transfer Standard, 7/8" Steel Ball, Steel Housing, 352#Cap

In stock at $12.40 Each

Quantity: 3

 

3. 8742K435

Polypropylene Sheet 1/4" Thick, 24" X 24", Translucent White

In stock at $17.97 Each

Quantity: 1

4. 9623K33

Spring-Tempered Steel Oval Wire Die Spring 1" Hole, 1/2" Rod, 1" Length, 7/32" X 7/64" Wire

In stock

Quantity Each 1-9 Each $3.55; 10 or more 2.80

Quantity: 2

5. 1488A13

Stainless Steel Surface-Mnt Hinge with Holes 316 SS, Polished, Nonremovable Pin, 2" H, 2" W

In stock at $6.24 Each

Quantity: 1

 

Miscellaneous Parts:

1. Couple of screws.

2. Cloth straps and padding.

 

First Test and evaluation:

 

 

Results:

Worked Better than expected! The hinge turned out to be kind of useless, and the design was undoubtedly bulky, but things will improve with the second prototype.

 

Useless hinge:

 

Distance View:

 

 

Close View:

 

 

 

Second Prototype:

 

Brainstorms:

 

Parts List:

 

McMaster Catalog:

 

1. 6421K66

Press-Fit Ball Transfer Standard, 5/8" Steel Ball, Steel Housing, 84# Cap

In stock at $8.83 Each

Quantity: 6

 

2. 3021T928

Elastic Hook-and-Loop Cinching Strap Black, 1" Wide, .093" Thick, 12" Overall Length

In stock at $1.85 Each

Quantity: 1

 

3. 3029T152

Elastic Hook-and-Loop Cinching Strap Black 1" Wide, .093" Thick, 18" Overall Length

Quantity: 1

 

Miscellaneous Parts:

1. Smooth-On C-1509 Semi-Rigid Casting Resin

2. Smooth-On FlexFoam-iT X

3. Modeling Clay

4. Saran Wrap

 

 

 

 

Results:

This prototype was much more comfortable than the first, given that it was molded to my arm using a clay mold and Smooth-On C-1509 Casting Resin. Upon initial testing, vibrations induced by rolling on rough surfaces was mildly uncomfortable due to the hardness of the cured resin. Pads made from Smooth-On FlexFoam-iT X were added to the elbow and wrist regions, effectively negating this concern.

 

The new base material proved to be more rigid than the quarter inch polypropylene sheet. In conjunction with the extra wheels, the second prototype eliminated the buckling seen in the first prototype, and also greatly increased the stability of the device in use.

 

Here are some photos of the second prototype:

 

 

 

 

 

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Final Results:

I was satisfied with the performance of my second prototype, so I decided to create a hip mounted roller so I could test the forearm pad in a more realistic situation. 

 

 

 

The system worked remarkably well on perfectly smooth surfaces, like wood paneling or polished concrete. Performance suffered however, on any surface much rougher than parking lot asphalt.

 

Sliding Indoors:

 

 

 

Sliding on Asphalt:

 

 

Final Notes:

 

     Upon outdoor testing, the forearm pad suffered from a lack of stability upon impact with the asphalt; it was difficult to keep the pad from rotating off of the ball bearings due to high frictional forces. Fortunately, the pad's design prevented me from getting scratched regardless. The hip mounted pad could certainly use improvements in ergonomics, but in general it functioned properly.

 

     If I were to continue developing this system, I might choose to make the forearm pad completely wraparound, so that landing orientation would become a complete non-issue.

 

As for meeting my initial requirements, the product performed admirably, surviving the requisite amount of abuse without significant loss of function. The cost of the pads ran slightly over $50 each however, although I'm sure that with mass production the devices would certainly decrease the cost to well under that $50. Overall, I would deem the project a success.

 

 

 

 

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