1. A folding collapsible treadmill comprising:
a base adapted for positioning on a flat surface, said base having two sidebars arranged in parallel at two sides;
a treadmill platform, said treadmill having a front side and a rear side, the front side of said treadmill platform being pivoted to a front side of said base for enabling said treadmill platform to be turned relative to said base between a horizontal operative position and a vertical non-operative position;
a positioning apparatus installed in said treadmill platform and adapted for locking said treadmill platform in said vertical non-operative position, said positioning apparatus having a movable stop member mounted in said treadmill platform, and a lever pivoted to one side of said treadmill platform and adapted for turning said movable stop member between a first position where said movable stop member is forced into engagement with a part of said base to lock said treadmill platform in said vertical non-operative position, and a second position where said movable stop member is disengaged from said base for enabling said treadmill platform to be turned relative to said base between said vertical non-operative position and said horizontal operative position; and
wherein said treadmill platform comprises two frame tubes longitudinally disposed at two sides and arranged in parallel, one of said frame tubes comprising a bottom lug disposed near a rear side thereof and adapted for supporting said lever and an inside guide block fixedly disposed near a front side thereof, said guide block having an elongated axle hole adapted for guiding movement of said stop member between said first position and said second position; said stop member is a latch inserted through said axle hole of said guide member for axial movement along said axle hole between said first position and said second position.
2. The folding collapsible treadmill as claimed in claim 1, wherein said positioning apparatus further comprises a connecting member connected between said stop member and said lever.
3. The folding collapsible treadmill as claimed in claim 2, wherein said lever is pivoted to said treadmill platform near a rear side of said treadmill platform and turned to pull said connecting member and to further move said stop member from said first position to said second position.
4. The folding collapsible treadmill as claimed in claim 3, wherein said lever comprises a circular base and a handle extended from said circular base; said connecting member is a steel rope having one end wound round said circular base of said lever and fixedly connected to a part of said circular base and an opposite end connected to a rear end of said stop member.
5. The folding collapsible treadmill as claimed in claim 1, wherein said base comprises a stepped stop portion formed in one sidebar thereof and adapted for stopping said stop member in said first position.
6. The folding collapsible treadmill as claimed in claim 1, wherein the frame tube of said treadmill platform in which said lever is installed comprises a locating plate fixedly provided on the inside near the front side thereof, said locating plate having a center through hole and two screw holes equally spaced from said center through hole at two opposite sides; said guide block has two mounting holes respectively fixedly fastened to the screw holes by a respective screw bolt; said stop member is mounted with a spring, having a flange extended around the periphery and stopped at one side of said guide block outside said axle hole, said spring being mounted on said stop member between the flange of said stop member and said locating plate to support said stop member in said second position.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
In the claims:
1. A method for synchronizing a plurality of bus systems, said method comprising:
transmitting synchronization signals from a transmission unit to an associated reception unit, where each bus system has at least one transmission unit and at least one associated reception unit; and
said transmission unit using a central clock to generate said synchronization signals autonomously for cyclic transmission to said associated reception unit, wherein said central clock is prescribed for each of said transmission units in a bus system.
2. The method of claim 1, wherein said reception unit in a bus system supplies the synchronization signals to a phase regulator in a phase locked loop having a clock transmitter, and upon receipt of said synchronization signals said phase regulator ascertains instantaneous phase errors and readjusts the clock transmitter such that said clock transmitter outputs a nominal number of clock signals between two synchronization signals, wherein said nominal number of clock signals is prescribed for all transmission units in said bus systems as said central clock.
3. The method of claim 1, further comprising a reception unit in a first bus system supplying synchronization signals to a phase regulator in a phase locked loop having a clock transmitter; upon receipt of said synchronization signals, said phase regulator ascertains instantaneous phase errors and readjusts the clock transmitter such that said clock transmitter outputs a nominal number of clock signals between two synchronization signals, wherein said nominal number of clock signals is prescribed as said central clock for a transmission unit in second another bus system.
4. The method of claim 2 or 3, wherein said phase regulator integrates the instantaneous phase errors to form an integration value, and wherein said integration value is corrected to form an integration fraction, with said integration fraction being less than one.
5. The method of claim 1, wherein a clock division is effected before said transmission unit is driven using a central clock.
6. The method of claim 1, wherein frequency multiplication is effected within the phase locked loop before a transmission unit is driven using a central clock.
7. The method of claim 2 or 3, wherein a message end of a clock message represents a respective clock instant, wherein said central clock generated by said phase locked loop is prescribed so that it is advanced by a delay time of a received clock message.
8. The method of claim 2 or 3, wherein a plurality of phase locked loops in a plurality of bus systems are cascaded.
9. The method of claim 8, wherein said frequency response of each of said phase locked loops has a gain of less than or equal to unity.
10. A hierarchical multibus system using synchronization, said system comprising:
a transmission unit; and
an reception unit associated with said transmission unit, said transmission unit transmitting synchronization signals to said associated reception unit, where each bus system has at least one transmission unit and at least one associated reception unit, said transmission unit using a central clock to generate said synchronization signals autonomously for cyclic transmission to said associated reception unit, wherein said central clock is prescribed for each of said transmission units in a bus system.
11. The method of claim 1, wherein said central clock is a common clock for all bus systems.