323,836 research outputs found
Lawn Rocker.
No full textPatent for a lawn rocker improvement that provides swing and is durable and inexpensive
Spring-Loaded Rocker-Bogie Suspension for Six Wheeled Rovers
No full textRovers equipped with articulated rocker-bogie suspension have aroused great interest after the explorations on Mars and their interest has also shifted to different types of terrestrial applications such as in the field of agriculture, rescue, etc. In this paper after analysing the distribution of loads on the wheels in different operating conditions, the possibility of equipping the passive hinge, that connects the rocker with the bogie, with a torsional spring with adjustable preload, is evaluated. The introduction of the spring has the aim of modifying the load on the wheels to favour the beginning of the overcoming of a step obstacle having height greater than the wheel radius
EFFECTIVENESS OF A NEW BALANCE TRAINING PROGRAM ON ROCKER BOARD IN SITTING IN STROKE SUBJECTS A PILOT STUDY
No full textBackground: Stroke has been considered to be the most common cause of neurological disability with very high prevalence rate. The recovery of independence following stroke is a complex process requiring the reacquisition of many skills. Since controlling the body’s position in space is essential part of functional skills, restoration of balance is a critical part of the recovery of ability after stroke. Most of the work done regarding balance training in stroke subjects has focused on task-oriented activities and training under varied sensory input and found them to be effective. Studies have also compared the effect of stable and unstable surfaces on balance in stroke subjects and found that balance training on unstable surfaces is more effective in improving static and dynamic balance. There has not been any study till date investigating the effectiveness of balance training program on rocker board which is specific for stroke subjects who have difficulty in standing. Since balance training on rocker board in sitting has proved to be effective in improving balance in subjects with spinal cord injury who have difficulty in standing, there is a need to find out if similar balance training program on rocker board in sitting is also effective for improving balance of stroke subjects.
Method: A Pilot study was performed on 10 stroke subjects selected through purposive sampling. Subjects were divided into two groups by randomization as control (CG) and experimental group (EG). EG received balance training on a rocker board along with conventional physiotherapy program. The CG received only conventional physiotherapy program.
Results: Post-intervention Berg balance scale score of EG and the CG was statistically significant (p < 0.05) in both the groups as compared to pre-treatment depicted through Wilcoxon signed rank analysis within the groups. Greater improvement was observed in the EG compared to the CG post-treatment, analysed through Mann-Whitney U test with statistically significant results (p < 0.05).
Conclusion: The new balance training program on rocker board in sitting is effective for improving balance of stroke subjects
Design of Rocker Bogie Mechanism
No full textAbstract: Rocker bogie are important for conducting in-situ scientific analysis of objectives that are separated by many meters to tens of kilometers. Current mobility designs are complex, using many wheels or legs. They are open to mechanical failure caused by the harsh environment on Mars. A four wheeled rover capable of traversing rough terrain using an efficient high degree of mobility suspension system. The primary mechanical feature of the rocker bogiedesign is its drive train simplicity, which is accomplished by using only two motors for mobility. Both motors are located inside the body where thermal variation is kept to a minimum, increasing reliability and efficiency. Four wheels are used because there are few obstacles on natural terrain that require both front wheels of the rover to climb simultaneously. A series of mobility experiments in the agriculture land, rough roads, inclined, stairs and obstacles surfaces concluded that rocker bogiecan achieve some distance traverses on field
Obstacle-climbing capability analysis of six-wheeled rocker-bogie lunar rover on loose soil
No full textTaking six-wheeled rocker-bogie lunar rover as an object, on the basis of force analysis between the wheels and lunar soil, its obstacle-climbing force model on loose soil was established in this paper, and the wheel sinkages were obtained. Based on the method of solving the wheel's driving torque solution space feasible regions, this paper analyzed the forward obstacle-climbing capability of six-wheeled rocker-bogie lunar rover on loose soil, including single-wheel obstacle-climbing and two wheels obstacle-climbing simultaneously. Simulations show that under the loose soil environment, the wheels have different obstacle-climbing capability, i.e. the rear wheel is the best, the middle one is the worst and the front one is moderate. © 2009 Springer-Verlag Berlin Heidelberg
Morris Mine, loading rocker-dump car
No full textDate scanned: 2002-6-20.USBM #64876; Haulage; loading 4-ton rocker-dump car from main-level chute. Morris Mine, Inland Steel Company, North Lake, Mich. - M. S. Petersen - October 1946.Held in the Russell L. and Lyn Wood Mining History Archive, Arthur Lakes Library, Colorado School of Mines.Donor: United States Bureau of Mines.Two miners load a rocker-dump car from a main-level chute underground at the Morris Mine. The Morris Mine was an underground iron mine in the Marquette Range, Marquette County, Michigan. The Mine was originally opened in 1909 in operation with the Lloyd Mine and known as the Morris-Lloyd Mine. It was operated as the Morris Mine by the Inland Steel Company starting in 1933 and continuing into the 1950s
Metatarsophalangeal Joint Dynamic Stiffness During Toe Rocker Changes With Walking Speed
No full textAccepted author manuscript version reprinted, by permission, from Journal of Applied Biomechanics, 2022, 38 (5): 320-327, https://doi.org/10.1123/jab.2021-0385. © Human Kinetics, Inc.Dynamic joint stiffness (or simply “stiffness”) is a customization criteria used to tune mechanical properties of orthotic and prosthetic devices. This study examines metatarsophalangeal (MTP) joint stiffness during the toe-rocker phase of barefoot walking and establishes baseline characteristics of MTP joint stiffness. Ten healthy individuals walked at 4 speeds (0.4, 0.6, 0.8, and 1.0 statures·s−1) over level ground. MTP sagittal plane joint angles and moments were calculated during the toe-rocker phase of stance. Least-squares linear regressions were conducted on the MTP moment versus angle curve to determine joint stiffness during early toe rocker and late toe rocker. Multilevel linear models were used to test for statistically significant differences between conditions. Early toe rocker stiffness was positive, while late toe rocker was negative. Both early toe rocker and late toe rocker stiffness increased in magnitude significantly with speed. This study establishes baseline characteristics of MTP joint stiffness in healthy walking, which previously had not been examined through a range of controlled walking speeds. This information can be used in the future as design criteria for orthotic and prosthetic ankle and ankle–foot devices that can imitate, support, and facilitate natural human foot motion during walking better than existing devices.This research is based upon work supported by the National Science Foundation’s Graduate Research Fellowship under Grant No.1940700. Any opinions, findings, and conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation
Distally Based Pedicled Fibula Flap for Reconstruction of Infected Charcot’s Midtarsal Collapse—Diabetic Rocker Bottom Foot
No full textIntroduction and Methods Diabetic rocker bottom foot with secondary infection exacts the expertise of a reconstructive surgeon to salvage the foot. The author selected 28 diabetic patients with secondarily infected Charcot’s degenerated rocker bottom feet and reconstructed their feet using distally based pedicled fibula flap. Reconstruction was done in a staged manner. Stage 1 surgery involved external fixation following debridement. In stage 2, struts were activated for distraction and arthroereisis. In stage 3, the distally based pedicled fibula was used for reconstruction and beaming of the arches.
Results In this retrospective study, the author analyzed the outcome of all 28 patients using the Musculoskeletal Tumor Society Rating (MSTSR) score. The average MSTSR score was 27.536 in an average follow-up of 30.5 months. The limb salvage rate with the author’s procedure was 96.4% (p = 0.045).
Conclusion Author’s protocol for the staged reconstruction and salvage of the infected diabetic rocker bottom foot, using the pedicled fibula flap, will be a new addendum in the reconstructive armamentarium of the orthoplastic approach
Fatigue crack propagation in rocker and roller-rocker bearings of railway steel bridges
No full textIn this work, a method is proposed for rolling contact fatigue crack propagation analysis using contact and fracture theories in conjunction with fatigue laws. The proposed method is used in the fatigue analysis of rocker and roller-rocker bearings of a railway open web girder
bridge which is instrumented with strain gages. Using a contact algorithm based on the minimum energy principle for bodies in rolling contact with dry friction, the normal and tangential pressure distribution are computed. It is seen that the most critical location of a crack in bearings is at a point very close to the contact region, as expected. (C) 2010 Elsevier Ltd. All rights reserved
New concept of a rocker engine - kinematic analysis
No full textThe paper presents concept and design of a four-stroke 4-cylinder internal combustion engine consisted of a single connecting rod to a crankshaft and four additional rods joining pistons with a rocker. The rocker is a specific element in the engine construction that makes this engine different from the typical reciprocating internal combustion piston engine. Furthermore, kinematical analysis of this piston - rocker - crankshaft mechanism was conducted. As concluded from the analysis, this mechanism implemented to the engine, provides several advantages with respect to both dynamic and thermodynamic related issues. First of all, a profile of the piston motion can be easily changed with change in the mechanism geometry e.g. major dimensions of connecting rods, the rocker etc. Thus, the piston motion profile can be asymmetrical with slow motion to and relatively fast distancing from the TDC. This feature can be useful in reducing thermal losses to an engine cooling system. Additionally, the mechanism characterizes itself with low transverse force from the piston, which acts on a cylinder liner. As a result, it significantly reduces frictional losses and should increase the overall efficiency of the engine. Among disadvantages, higher inertial forces are the most important problem. As analyzed, the rocker is the main component that contributes to increase in inertial forces by approximately three to four times. On the other hand, total inertia forces, due to specific kinematical chain of the mechanism, can be remarkably reduced in case the mechanism is correctly optimized
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