Implements or apparatus for applying pushing or pulling force – Single throw lever – Mechanically actuated
Reexamination Certificate
1999-08-25
2001-04-10
Hail, III, Joseph J. (Department: 3723)
Implements or apparatus for applying pushing or pulling force
Single throw lever
Mechanically actuated
C254S00900C
Reexamination Certificate
active
06213451
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a lifting apparatus for motor vehicles, mounting units, machines, or the like and more particularly to such a lifting apparatus with at least one scissors arrangement and a base frame.
2. Discussion of Relevant Art
A lifting device is known from a brochure of the OMER Company, and has a base frame with at least one scissor type arrangement. The scissor type arrangement has a first bearing with a pivot axis around which a stationary strut is rotatably arranged. The opposite end of the strut engages a carrier arm and forms a second bearing. The carrier arm is divided by the strut into a first and second carrier arm section, and has a guide at the free end of the second carrier arm, which is associated with the base frame. By means of the guide, the second carrier arm section is guided, movable horizontally back and forth, in the base frame. The carrier arm has, at its end opposite to this, a further bearing at which a load receiver is arranged.
This lifting device is moved up and down by a lifting cylinder, which has one end arranged on the strut near the second bearing, and which acts with its other end on a second strut which in turn is pivotably arranged on the first carrier arm section and is connected to the load receiver. By this arrangement, a double half scissors is formed, which is driven by the lifting cylinder situated in between in order to effect an up and down movement. This arrangement of a lifting platform is constructionally expensive. Furthermore, this lifting apparatus is built high when not in use and is thus inconvenient for use. The lifting apparatus is thus mainly suitable for building into the floor of a workshop. The relative height when not in use is a result of an expensive arrangement of the lifting cylinders which is provided between the struts, so that the required force can be applied in order to move the lifting apparatus out of a dead point position or an unextended position. Constructional measures are employed in order to be able to overcome the high forces, leading to a relatively high construction of the lifting apparatus in an initial position. Furthermore, such an configuration of the lifting apparatus is limited to a few cases of use and is costly in its configuration.
SUMMARY OF THE INVENTION
The invention therefore has as its object to provide a lifting apparatus, which is of simple construction, has favorable force conditions during the whole lifting process, preferably at the beginning of the lifting path, and can be embodied in flat construction. The invention has as a further object to provide a lifting apparatus, which can be used for many uses.
This object is attained, according to the invention, by a lifting apparatus with at least one scissors arrangement and a base frame, having a first bearing with a rotation axis; a strut arranged to be pivotable around the rotation axis; a carrier arm that has a second bearing in common with the strut, the strut dividing the carrier arm into a first and a second carrier arm section the second carrier arm section, forming a triangle with the strut and the base frame; a guide that has a fourth bearing arranged on the guide for receiving the second carrier arm section, which guide can move back and forth on the base frame; a load receiver arranged on a fifth bearing at a free end of the first carrier arm section; at least one lifting unit that acts on the carrier arm; and a parallelogram guide with which the load receiver is aligned horizontally, in which a resultant force acting on the load receiver runs along a straight line extending between the first and fifth bearings or is situated outside a movement space of the scissors arrangement circumscribed by the first, fourth and fifth bearings.
By the constitution of the lifting apparatus according to the invention, it is possible for the lifting apparatus to carry out, on the one hand, a linear lifting movement according to the principle of a punch platform, and can furthermore be designed in a flat construction. The construction according to the invention, in particular of a half scissors, in which the load reception by a parallelogram guide is directed horizontally, makes possible a constructionally simple constitution which can accept considerable forces. Favorable force distributions within the scissors arrangement can furthermore be made possible by the introduction of the force resultant, so that a lifting apparatus can be provided cost-effectively with a low cost in materials.
By the arrangement of a load receiver, which is substantially situated in front of a fifth bearing or outside the movement space between the first, fourth and fifth bearings, an apparatus of flat construction can be provided. The lever arm, which then exists between the force introduction of the resultant force and the fifth bearing, is negligible, and furthermore can be compensated by a pull rod without problems. It can also be provided that the force receiver is situated in the region of the fifth bearing of the scissors arrangement.
According to a further advantageous configuration, it is provided that the parallelogram guide is constructed as a pull rod, so that the lifting movement passes through the fifth bearing of the scissors arrangement. The resultant force, or the load reception, is thereby provided to the fifth bearing in such a manner that exclusively tension forces can act on the pull rod, whereby its design is considerably simplified in contrast to a design for pressure.
A further advantageous configuration provides that the parallelogram guide is constructed as at least one further scissors arrangement with or without a lifting unit, and is coupled to a connecting means which acts on the first scissors arrangement. In this alternative configuration, the pull rod can be dispensed with. Moreover the fifth bearing can run thorough the lifting movement or be anchored fixed to the floor. This further alternative configuration has the advantage that a cost reduction can result from the use of, for example, two scissors arrangements, because of the identity of the components. Maintenance and assembly are also simplified.
By means of an acute angled arrangement of at least one lifting unit to a strut of a scissors arrangement which acts on a carrier arm it is advantageously made possible that favorable force relationships result, particularly when lifting the load from an inoperative position. A dead center position of the lifting unit in an inoperative position of the lifting apparatus can be avoided by this arrangement, and the lifting movement can be carried out with a considerably smaller expenditure of force. At the same time, it can be made possible by this configuration that a flat construction of the lifting apparatus can be provided. When built into a floor or workshop floor, this has the advantage that only minimal foundation work is required. With an arrangement on the floor, such a lifting apparatus of low or flat construction can be traveled over by vehicles without problems. Furthermore, the minimal overall height can lead to a reduction of material costs and thus of the production costs.
According to a further advantageous configuration of the invention, it is provided that a third bearing, which is formed by the action of the lifting unit on the carrier arm, is provided outside an axis between the second and fourth bearings. The lifting cylinder can thereby have a location that deviates from the strut in the inoperative state, thus making it possible for the lifting cylinder to be adjusted by an acute angle in the direction of the lifting movement. The force can thereby be reduced according to a cosine function corresponding to the setting of the angle. In dependence on the size of the cylinder, the adjustment angle can be advantageously adjusted with respect to a horizontal line, so that on the one hand the scissors arrangement
Hail III Joseph J.
Shanley Daniel
LandOfFree
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