1. A pressure-medium cylinder having a piston which has a piston rod (11), and having a measuring system for determining the position of the piston rod (11) relative to a reference point, with the measuring system having a code track of binary code elements (30, 31) which is applied to the piston rod (11) and runs along the piston rod (11), which code elements (30, 31) are formed by grooves (30) and plateaus (31) which run in the circumferential direction in a magnetically conductive base material (13), which is coated with a protective layer (14), of the piston rod (11), and with the measuring system having a sensor (20) which is in a fixed position relative to the reference point and has two or more sensor elements (50), which are arranged along the code track and each scan a limited number of code elements (30, 31), characterized in that, in order to determine the absolute position of the piston rod (11), the code elements (30, 31) in the code track on the piston rod (11) are arranged in an irregular pattern, which in each case produces a unique pattern of the output signals from the sensor elements (50) for different positions of the piston rod, and in that the grooves (30) and plateaus (31) in the piston rod form, at least in wide areas, a Manchester Code, in which at most two code elements (30, 31) of the same state follow one another.
2. The pressure-medium cylinder as claimed in claim 1, characterized in that the code track on the piston rod (11) is composed of code words (35) which are each formed from an equal number of binary code elements (30, 31) and which all have a start code (33), which is formed from a specific number of code elements (30, 31), and, following this, an individual position code (31), which comprises a sequence of code elements (30, 31) which is specific only to that particular code word (35), in that the arrangement of the sensor elements (50) of the sensor (20) extends at least over the length of an entire code word (35), and in that the number of sensor elements (50) within the length of a code word (35) is at least as great as the number of code elements (30, 31) in the code words (35).
3. The pressure-medium cylinder as claimed in claim 1 or 2, characterized in that the number of sensor elements (50) within a specific length of the code track is an integer multiple of the number of code elements (30, 31) within the length.
4. The pressure-medium cylinder as claimed in claim 3, characterized in that there are twice as many sensor elements (50) as code elements (30, 31) within the specific length, and the distance between the sensor elements (50) is thus half as great as that between the code elements (30, 31).
5. The pressure-medium cylinder as claimed in claim 2, 3 or 4, characterized in that the row of sensor elements (50) is at least as long as one code word (35) plus one start code (33).
6. The pressure-medium cylinder as claimed in claim 5, characterized in that the row of sensor elements (50) is longer than one code word (35) plus one start code (33), and is preferably 130% of one code word (35).
7. The pressure-medium cylinder as claimed in one of claims 2 to 6, characterized in that the start code (33) is the same for all the code words (35) on the code track on the piston rod (11).
8. The pressure-medium cylinder as claimed in one of claims 2 to 7, characterized in that only the position code (34) is a Manchester Code, and in that the start code (33) has at least three immediately successive code elements (30) of the same state.
9. The pressure-medium cylinder as claimed in one of the preceding claims, characterized in that the sensor elements (50) are Hall elements, which are subjected to the field from a permanent magnet (45) which, in particular, is composed of the rare earth metal neodymium.
10. The pressure-medium cylinder as claimed in claim 9, characterized in that a housing (21) together with the sensor elements (50) and the associated electronics are arranged in the cylinder head (12).
11. The pressure-medium cylinder as claimed in claim 10, characterized in that the housing (21) has a base part (40) composed of aluminum, into which the sensor elements (50), the permanent magnet (45) and various electrical printed circuit boards (41, 42, 43, 44) are inserted, and has a cover (46) composed of steel.
12. The pressure-medium cylinder as claimed in one of the preceding claims, characterized in that two or more sensors are arranged distributed around the piston rod.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A current collector for a rail vehicle, the current collector being adapted to travel along a power rail that transmit electric energy to the rail vehicle via the current collector, and the current collector comprising:
a contact shoe device including an upper sliding contact surface and a lower sliding contact surface, the upper sliding contact surface for forming a sliding contact with an upper contact surface of said power rail, and the lower contact surface for forming a sliding contact with a lower contact surface of said power rail; and
a pressing-on device attached to the contact shoe device and allowing the contact shoe device to move between an upper sliding contact position and a lower sliding contact position;
wherein the pressing-on device applies a pressing-on force to the contact shoe device in a first direction, when the contact shoe device is in the upper sliding contact position, and applies a pressing-on force to the contact shoe device in a second direction, when the contact shoe device is in the lower sliding contact position;
the pressing-on force applied in the first direction forms the sliding contact between the upper sliding contact surface of the contact shoe device and the upper contact surface of the power rail; and
the pressing-on force applied in the second direction forms the sliding contact between the lower sliding contact surface of the contact shoe device and the lower contact surface of the power rail.
2. The current collector of claim 1, wherein:
the pressing-on device comprises a rocker unit having an unloaded position, the rocker unit being rotationally moveable from the unloaded position, to allow the contact shoe device to move between the upper sliding contact position and the lower sliding contact position; and
the rotational movement of the rocker unit from the unloaded position brings about formation of the pressing-on forces.
3. The current collector of claim 2, further comprising a carrier device, and wherein the pressing-on device further comprises a holding device that fastens the rocker unit to the carrier device.
4. The current collector of claim 2, wherein the rocker unit comprises a spring device that forms the pressing-on forces.
5. The current collector of claim 4, wherein the spring device comprises a first coil spring and a second coil spring, the first coil spring forming the pressing-on force applied in the first direction, when the contact shoe device is in the upper sliding contact position, and the second coil spring forming the pressing-on force applied in the second direction, when the contact shoe device is in the lower sliding contact position.
6. The current collector of claim 5, wherein a spring force of the first coil spring is greater than that of the second coil spring.
7. The current collector of claim 4, further comprising:
a carrier device; and
wherein the pressing-on device further comprises a holding device that fastens the rocker unit to the carrier device;
the rocker unit further comprises a sleeve that provides the rotational movement of the rocker unit, the sleeve being mounted on the holding device in a rotationally moveable manner, and the sleeve surrounding the spring device; and
the contact shoe device is fastened to the sleeve of the rocker unit.
8. The current collector of claim 7, wherein the spring device comprises a spring being coupled to the sleeve and to the holding device, such that rotation of the sleeve with respect to the holding device causes the spring to form at least one of the pressing-on forces.
9. The current collector of claim 7, wherein:
the spring device comprises a spring holder, a first coil spring and a second coil spring, the first coil spring being coupled to the sleeve and being connected to the spring holder in a rotationally fixed manner, and the second coil spring being coupled to the sleeve and being connected to the spring holder in a rotationally fixed manner;
the first coil spring forms the pressing-on force applied in the first direction, when the contact shoe device is in the upper sliding contact position; and
the second coil spring forms the pressing-on force applied in the second direction, when the contact shoe device is in the lower sliding contact position.
10. The current collector of claim 7, wherein:
the spring device comprises a first spring holder, a second spring holder, a first coil spring and a second coil spring, the first and second spring holders being rotationally fixed with respect to one another and mounted within the sleeve, the first coil spring being coupled to the sleeve and being connected to the first spring holder in a rotationally fixed manner, and the second coil spring being coupled to the sleeve and being connected to the second spring holder in a rotationally fixed manner;
the first coil spring forms the pressing-on force applied in the first direction, when the contact shoe device is in the upper sliding contact position; and
the second coil spring forms the pressing-on force applied in the second direction, when the contact shoe device is in the lower sliding contact position.
11. The current collector of claim 10, wherein a spring force of the first coil spring is greater than that of the second coil spring.
12. The current collector of claim 10, wherein the spring device further comprises a first spring claw, a second spring claw and a coupling element, the first spring claw being connected to the first coil spring in a rotationally fixed manner, the second spring claw being connected to the second coil spring in a rotationally fixed manner, and the coupling element being connected to the sleeve and engaged with each of the first and second spring claws so as to couple the first and second coil springs to the sleeve.
13. The current collector of claim 12, wherein the coupling element engages with the first and second spring claws such that:
when the coupling element rotates with the sleeve according to the movement of the contact shoe device to the upper sliding contact position, the coupling element rotates relative to the second spring claw and moves the first spring claw against a spring force of the first coil spring; and
when the coupling element rotates with the sleeve according to the movement of the contact shoe device to the lower sliding contact position, the coupling element rotates relative to the first spring claw and moves the second spring claw against a spring force of the second coil spring.
14. The current collector of claim 13, wherein:
the rotation of the of coupling element relative to the second spring claw is limited by a stop formed on the second spring claw; and
the rotation of the coupling element relative to the first spring claw is limited by a stop formed on the first spring claw.
15. The current collector of claim 12, wherein the spring device further comprises an axle, the coupling element and the first and second spring claws are rotatably arranged on the axle.
16. The current collector of claim 15, wherein:
the axle and the first and second spring holders are fixed in a rotationally fixed manner on the holding device.