David Renfroe

US Patent:

6709013, Mar 23, 2004

Filed:

Mar 20, 2002

Appl. No.:

10/103389

Inventors:

David A. Renfroe - Fayetteville AR
Joe Partain - Fayetteville AR

Assignee:

University of Arkansas - Little Rock AR

International Classification:

B62D 112

US Classification:

280778, 280 93506, 280269

Abstract:

There is disclosed lever steering apparatus for a land vehicle with steerable and independently suspended front wheels having left and right steering levers at the driver position. The left and right steering levers are coupled by lever mechanisms and an elongated rod to move in opposite directions. Left and right fore and aft links extend from the left and right steering levers to the left and right front wheels to transmit steering motion displacement to the steerable front wheels causing rotation of the axles of the wheels about a vertical axis. A controller arm connected to each wheel stub axles is connected to the forward end of a fore and aft link for steering motion of a front wheel. The control arm fore and aft link combination causes each wheel steering motion to have a predetermined relation to motion of the corresponding link.

US Patent:

7028351, Apr 18, 2006

Filed:

Dec 30, 2004

Appl. No.:

11/028417

Inventors:

Russell Frieder - Santa Barbara CA, US
Srirangam Kumaresan - Goleta CA, US
Anthony Sances, Jr. - Santa Barbara CA, US
Seong K. Mun - McLean VA, US
David Renfroe - Fayetteville AR, US
Will J. Myers - Rogers AR, US

Assignee:

Calzark - Goleta CA

International Classification:

A61G 3/00
B64D 25/04

US Classification:

5118, 5 91, 5627, 2441186, 296 19

Abstract:

A modular patient support system adapted to be quickly mounted to utility vehicles such as trucks, buses, vans or trailers, to permit emergency medical workers to rapidly transform standard utility vehicles into specialized ambulances. When not in use, the modular patient support system is easily dismounted and collapsed for warehousing. The modular patient support system comprises a base frame that is used to attach the system to a vehicle. The base frame is oriented parallel and adjacent to a side wall of the vehicle. Two telescoping litter supports are attached to the base frame by hinges having a vertical axis of rotation. The two litter supports can either be extended normal to the base frame in order to support a patient on a litter, or collapsed and folded parallel to the base frame. A seat frame is adjustably attached to the base frame using multiple connecting links. When positioned vertically, the seat bottoms serve as mounting surfaces for medical equipment.

US Patent:

7073822, Jul 11, 2006

Filed:

Jun 3, 2003

Appl. No.:

10/454034

Inventors:

David A. Renfroe - Fayetteville AR, US
Joe Partain - Fayetteville AR, US

International Classification:

B62D 1/00

US Classification:

280771, 280 9351, 280 93502

Abstract:

A steering suspension system utilizing a flexible push/pull cable attached from an operator input mechanism across a suspension system to a wheel steering mechanism. An operator input mechanism is located within a land vehicle structure supported by a wheel. A suspension system connects the wheel to the land vehicle structure and a wheel steering mechanism is used to connect the wheel to the suspension system. The flexible cable connection minimizes the complexity in number of parts for the steering system while providing a flexible connection to the wheel steering mechanism allowing free suspension movement with minimal or negligible affects provided from the steering linkage.

US Patent:

8108976, Feb 7, 2012

Filed:

Jun 19, 2007

Appl. No.:

11/820596

Inventors:

Chandrashekhar K. Thorbole - Fayetteville AR, US
David Renfroe - Fayetteville AR, US

International Classification:

A44B 11/26

US Classification:

24650

Abstract:

A buckle for a seat belt that resists unintentional unlatching when subjected to rapid acceleration or deceleration. The buckle assembly includes a female buckle and a removable male tongue plate. The female buckle includes a spring-loaded pawl that lockingly engages a slot in the removable tongue plate. The spring urges the pawl into locking engagement with the slot in the tongue plate. The present invention discloses a pawl-loading spring made from a material that resists elastic deformation when the buckle is subjected to a force perturbation such as the sudden acceleration or deceleration of the buckle that occurs during a crash. The spring material exhibits resistance to deformation when loaded at a high loading rate.

US Patent:

20130125355, May 23, 2013

Filed:

May 15, 2012

Appl. No.:

13/471812

Inventors:

Chandrashekhar THORBOLE - Springdale AR, US
David RENFROE - Fayetteville AR, US

Assignee:

THE ENGINEERING INSTITUTE, LLC - Farmington AR

International Classification:

A44B 11/25

US Classification:

24633

Abstract:

A seat belt buckle assembly for resisting unintentional opening during rapid acceleration or deceleration. The seat belt buckle assembly includes a female buckle, a male tongue plate, a pawl assembly, a spring and a load rate sensitive foam member. The female buckle is a casing with an open end that is adapted to receive the substantially planar male tongue plate provided with a slot. The pawl assembly housed within the casing includes a pawl that fits within the slot. The spring disposed between casing and pawl assembly urges the pawl into slot and elastically deforms when subjected to force. The load rate sensitive foam member interposed between spring and pawl assembly transmits load applied on pawl to spring for facilitating compression of spring and therefore unlatching of the buckle in case of gradual loading, but inhibiting involuntary compression of spring by absorbing most of the impulsive loading.

US Patent:

56533047, Aug 5, 1997

Filed:

Jun 6, 1995

Appl. No.:

8/466375

Inventors:

David A. Renfroe - Fayetteville AR

Assignee:

University of Arkansas, N.A. - Little Rock AR

International Classification:

B62D 500

US Classification:

180402

Abstract:

A steering system in an all-terrain four-wheeled vehicle with independent suspension wherein necessary forces for wheels to respond to steering control is supplied by fluid pressure or electrical actuators mounted parallel to the suspension arm between vehicle frame and wheel control arm, steering control by the driver being by manipulation of right and/or left steering levers eliminating the need of steering wheel and steering column in front of the driver. The steering actuators are independent and there is no tracking rod or other linkage for coordinating their turning angles; rather, close coordination of the wheel turning angles for achieving the Ackerman angle relation or other non-linear turning angle relation between the wheels is by a now-linear linkage between left and right steering levers or elsewhere or by a computer control for electric actuators. Optionally, a computer control in an electrical system has inputs for acceleration and velocity for detecting hazards associated with steering and inputs to provide artificial feel signals to the hand levers.

US Patent:

54354072, Jul 25, 1995

Filed:

Apr 20, 1994

Appl. No.:

8/230311

Inventors:

David A. Renfroe - Fayetteville AR

Assignee:

University of Arkansas - Little Rock AR

International Classification:

B62D 314

US Classification:

180 79

Abstract:

There is disclosed a steering system for a wheeled vehicle, particularly one with independent suspension of the steerable wheels, which is characterized by the lack of any necessity for a direct physical linkage between steering control arms of the left and right wheels and by the use of separate, independent fluid pressure cylinder pairs connected by fluid pressure conduit for imparting motion to the respective steerable wheels. Coordination between the angular motion of the left and right steerable wheels is attained by a direct mechanical linkage between actuator members of the hydraulic cylinders remote from the wheel suspension which linkage can be arranged for non-linear relative motion which will result in desired coordinated but unequal motion of left and right steerable wheels. Such linkage between actuator members is operated directly or indirectly by the steering wheel, steering levers, or other device. Preferably the fluid pressure cylinders connected to steering control arms of the wheels extend substantially parallel to suspension arms of the wheel suspension, and fluid pressure lines to such cylinders are flexible hoses which permit wide angle motion of the independent wheel suspension.

US Patent:

59312440, Aug 3, 1999

Filed:

Oct 9, 1996

Appl. No.:

8/728540

Inventors:

David A. Renfroe - Fayetteville AR
Joseph F. Partain - Fayetteville AR

Assignee:

Board of Trustee of University of Arkansas - Little Rock AR

International Classification:

B60K 1730

US Classification:

180 632

Abstract:

A steering system in an all-terrain four-wheeled vehicle with independent suspension wherein necessary forces for steering control are supplied by cable and pulley actuators with the cable running parallel to the suspension arm between vehicle frame and wheel, steering control by the driver being by manipulation of right and/or left steering levers eliminating the need of steering wheel and steering column in front of the driver. The steering actuators are independent and there is no linkage for coordinating their turning angles; rather, close coordination of the wheel turning angles for achieving the turning angle relation between the wheels is by a non-linear linkage whereby the actuators are provided with separate displacement motions with the non-linear relation to achieve the desired relation between the steering angles of the wheels.