The patent for the Horst Link, which is Leitner's most famous patent, was registered on September 9, 1994 and issued on April 23, 1996. However, the patent will expire on September 9, 2014. The patent that was issued was an extension of a patent registered January 21, 1993. This particular patent was an "extension in-part" of a patent filed the previous year to the day. http://patent.ipexl.com/inventor/Horst_Leitner_1.html
There are numerous designs almost identical to the Horst Link, but are diverse enough to prevent patent infringement. One of the most popular models is the "faux bar" linkage, contrasting with Horst four-bar linkage. The faux-bar linkage shifts the pivot on the back of the bicycle off the chain-stay and on the seat-stay. There are some who utilize this design claiming that it works just the same, if not better, than Leitner's four-bar linkage. Certain companies license the Horst Link model from Specialized as well, with the most popular probably being Titus. Here are several of Horst Leitner's patents starting in the 2000s. However, the below written text is a modification of the original text. You can read the original patent text at faqs.org
20090250957-(VEHICLE CARGO BED-EXTENDER): A vehicle-bed extender especially modified for easy installation and detachment. This extender consists of a first and second side-wall, a joining wall, a first and second mount, and a first and second mounting station. The joining wall, the first and second side-wall work together to produce a slight curved frame. The first and second mounting station each consists of a stationary segment and a moveable segment designed so that the portable part is structured and that the portable segment, in a first-position, works with the unmoving part to connect the first or second mount and to thwart detachment. The moveable segment of the first and second mounting-station can be transported by a layman's use of force applied to a second position that permits this type of disconnection. In a favored personification, an ameliorated truck bed-extender is supplied that is especially modified for easy installation and detachment. When not in use to elongate the truck-bed, the extender beneficially adjusts to a fast and simple space of additional storage. Published 10/08/2009
20100007166-(VEHICLE SEAT ASSEMBLY): A vehicle-seat assembly that rises and pivots to ameliorate travelers seat access. The vehicle-seat components consists of a seat and multiple links pivotally joined to a lower-surface of the seat at one end of each link and pivotally affixed with to a vehicle floor at the opposing end of each link. A motor can be utilized to power a minimum of one link to start the seat.
Former vehicle-seats have proposed raising modifications to supply travelers with adjustability while sitting, for instance, to permit a passenger to choose a more comfortable position or acquire a better view. Nonetheless, vehicle-seats have not frequently been designed to be height adjusted to endorse vehicle entering and exiting, and have not proposed rotating abilities. By simply raising the passenger, the device frequently aids the traveler with access to their seat without being uncomfortable when between the vehicle roofline and a now raised seat. Consequently, there is a necessity for a vehicle-seat that turns the traveler towards the vehicle door, while raising the individual for access to easy entering and exiting from the vehicle. Published 1/14/2010
20100059962-(RETRACTABLE VEHICLE STEP): A retractable step for usage with a pickup incorporates a stepping device and a first and second-arm. The first-arm has a first-end pivotally affixed to the vehicle, and a second-end pivotally affixed to the stepping device. The second-arm includes a first-end pivotally affixed to the pickup, and a second-end pivotally affixed to the stepping device. In conjunction with one personification, a withdrawable step for usage with a vehicle incorporating a stepping device with a stepping-deck, a first and second-arm, a stop, and motor. The first-arm has a first-end with a turning apparatus affixed to the vehicle, and a second-end turning apparatus affixed to the stepping device.
The second-arm includes a first-end turning apparatus affixed to the vehicle, and a second-end turning apparatus affixed to the stepping member. The motor is power linked to the first-arm so that a rotation of the motor produces a rotary motion of the first-arm near its first-end and moves the stepping device from a withdrawn position to a protruding position, and vice-versa. The stop is situated within the scope of movement of the second-arm so that the second-arm presses against the stop when the stepping device is in the protruding position. The first and second-arms are positioned so that the first-arm is laden in firmness and the second-arm is loaded in tension when the stepping device is in the protruding position and cargo is placed upon it. Published 3/11/2010
201002327581-(MOVEABLE SUPPORT PLATFORM): A withdrawable truck step can be fixed to a truck or vehicle. The vehicle/truck step makes it easier for vehicle owners to access the cargo hold in the back of their truck. Favorably, the vehicle-step can be drawn from beneath the vehicle with a simple tap of the foot. The vehicle-step has a much-needed covered and shielding biasing mechanism for changing between a retraction and extending position.
Some personifications of the above invention supply a retractable vehicle-step that can be mounted to the back part of a truck or vehicle. The vehicle-step permits access to the cargo-hold of the vehicle. Another benefit is that the vehicle-step can be quickly mounted to the vehicle or truck utilizing prepared connection components; thereby doing away with or extenuating the requirement for bespoke retrofitting and decreasing or preventing unnecessary installation saving money and time. Published 9/23/2010
20110101720-(VEHICLE CARGO BED EXTENDER): A better-made truck bed-extender especially modified for simple installation and removal. When not in use, the extender can be easily used as additional storage space. In one personification, the extender incorporates a first and second side-wall, a linking wall, and a first and second mount. The linking wall expand between the first and second side-wall, and assists with the first and second side-wall to create a frame. The first mount is affixed to the first side-wall and contains a first interconnecting member. The initial interconnecting member and a first mounting-station on the vehicle and the second interconnecting member and a second mounting-station on the vehicle works together to safeguard the truck bed-extender to the vehicle.
One of their main benefits is the capability to carry cargo in the storage bed positioned in back of the cab of the vehicle. Regrettably, frequently the storage bed is an awkward form for the cargo being carried. Therefore, it is not uncommon for the cargo to be bigger than the truck bed itself, making it difficult with a tailgate lowered in order to fit the cargo to be transferred. This is why the bed-extender is extremely practical and a fantastic idea for all pick-up truck owners. Published 5/5/2011
20110115187-(TAILGATE ACCESS STEP): A protractible vehicle-step that can be mounted to the backside of truck or vehicle. The vehicle-step makes it easy to access cargo in the back of the truck. Beneficially, the vehicle-step offers a clearance area in conjunction to the tailgate of the vehicle by moving a stepping part of the vehicle-step in an overall sideways direction. The vehicle-step advantageously has a finish and protected biasing-mechanism for conversions between the withdrawn and protruding positions of the vehicle-step. An additional advantage is that the vehicle-step is easily affixed to the vehicle utilizing pre-existing connection parts, thereby usually removing or mitigating the requirement for bespoke retrofitting and preventing unnecessary installation situations. Published 5/19/2011
20110298262-(VEHICLE SEAT-ASSEMBLY): A vehicle-seat assembly that lifts and revolves to improve passenger access to seating. The vehicle-seat consists of a seat and multiple links pivotally joined to a lower-surface of the4 seat at one end of each link and pivotally-mounted to the vehicle floor at the opposed end of each of the links. A tool can be utilized to drive at least one of the links to set the seat into motion. Preceding vehicle-seats have proposed height adaptability to supply passenger adjustability while in the seated position, for instance to permit a passenger to choose a more comfy seating position or attain a better view. Nonetheless, these vehicle-seats are not usually designed by height modification to endorse vehicle entering and exiting, and have not proposed rotation adjustability. Simply raising the passenger frequently will not assist with access to the seat as a vehicle passenger would then be uncomfortable and have to squeeze away from a smaller opening between the vehicle roofline and a now higher seat position. Consequently, there is a desire for a vehicle-seat that turns a passenger towards the vehicle door, while raising the traveler to position for better entering and exiting of the vehicle. Published 12/8/2011
20130038035-(RETRACTABLE VEHICLE STEP): A retractable step for utilization with a vehicle incorporates a stepping segment with an upper-stepping façade, and a first and second arm. The first-arm consists of a first end pivotally affixed to the vehicle, and a second end pivotally affixed to the stepping mechanism. The second-arm includes a first end pivotally affixed to the vehicle, with a second end turning movement affixed to the stepping device. In conjunction with the one personification, a retractable step that is used with vehicles incorporates a stepping device with a stepping-deck, first and second arm, a stop, and motor.
The first-arm has a first-end turning apparatus affixed to the vehicle, and a second-end turning apparatus affixed to the stepping device. The second-arm includes a first-end turning apparatus affixed to the vehicle, and a second-end pivotally affixed to the stepping device. The motor is power linked to the first-arm so that the revolving of the motor causes rotation of the first-arm around its first-end and moves the stepping device from a withdrawn position to a protruding position or vice-versa. The stop is positioned within the scope of motion of the second-arm so that the second-arm stands against the stop when the stepping device is in the protruding position. The first and second-arms are positioned so that the first-arm is loaded in firmness and the second-arm is loaded in tautness when the stepping device is in the protruding position and a load is pressured. Published 2/14/2013
The above mentioned patents only touch the surface of the many patents that Horst Leitner registered. One site (patent.ipexl.com) lists no less than 87 patents registered by Leitner!