Implements or apparatus for applying pushing or pulling force – Apparatus for hauling or hoisting load – including driven... – Device includes rotatably driven – cable contacting drum
Patent
1980-04-10
1982-10-12
Jillions, John M.
Implements or apparatus for applying pushing or pulling force
Apparatus for hauling or hoisting load, including driven...
Device includes rotatably driven, cable contacting drum
254343, 254346, 254362, 254903, B66D 112, B66D 120
Patent
active
043535267
DESCRIPTION:
BRIEF SUMMARY
FIELD AND BACKGROUND OF THE INVENTION
The invention relates to an electrical drive for a vertically displaceable blackboard. In today's conventional very wide and relatively low blackboards such as are used in lecture halls there is the problem of canting of the board in its guides. In such wide blackboards, for example, a shaft mounted above the lateral guide beams guarantees synchronous operation of both of the cables or chains arranged on the sides of the blackboard. In Swiss Pat. No. 600,832 a drive system with two parallel connected hydraulic motors is described. In drives with electric motors use has been made of the possibility of a so-called electric shaft.
OBJECTS AND SUMMARY OF THE INVENTION
It is the object of this invention to make the drive with two simple electric motors without an electric shaft whereby in particular building into the lateral guide beams is possible. The invention attains these objects with a drive apparatus which is characterized in that an electric motor is combined with a worm drive, a drive sheave, and a slip coupling into a unit which is mountable in the hollow guide beams with the motor arranged vertically and having a hollow shaft through which the drive cable is guided.
It is advantageous if the slip coupling is so constituted that at least during assembly it can release the driven sheave. This allows the weight of the blackboard to be balanced exactly against the weight of the two counterweights.
BRIEF DESCRIPTION OF THE DRAWING
An embodiment of the invention is shown in the drawing:
FIG. 1 shows the drive apparatus when built in, partly in section;
FIG. 2 shows the same apparatus in a side view;
FIG. 3 shows a portion of the apparatus in enlarged scale; and
FIG. 4 shows two discs in perspective view.
SPECIFIC DESCRIPTION
In the drive apparatus shown in FIGS. 1 and 2 the guide beam F, in whose upper region the apparatus is mounted, is shown by thick dot-dash lines. The driven sheave 40 projects slightly from the beam and has at least in this region a recess.
The motor housing 10 is widened in its upper region to provide space for the worm drive 20 mounted in it. The worm 21 is mounted on the hollow shaft 31 of the electric motor 30. The worm gear 22 is fixed on a shaft 23 which projects from one side out of the housing 10.
The hollow shaft 31 of the motor 30 is rotatably mounted at its top and bottom in the housing in roller bearings 32. The cover caps 11 for these bearings each have a fixed (non-rotating) guide tube 12 concentric with the hollow shaft 31. A cable S is guided through the tube 12. An end of the cable is connected with a counterweight C mounted in the guide beam. The other end of the cable S is hooked on the blackboard B. The cable is to this end guided over the sheave 40.
The sheave 40 is driven by a toothed wheel 24 fixed on the shaft 23 with the help of a toothed belt 25. To this end a toothed wheel 26 is mounted on the shaft 41 on which the sheave 40 is mounted. The shaft 41 is rotatably mounted in the mounting plates 13 and 14 which are connected with the housing 10. The mounting plate 13 is fixed; the plate 14 is removable from the housing 10.
The shaft 41 with the parts mounted on it is shown in FIG. 3 in larger scale. The toothed wheel 26 and a disc 42 provided with a brake pad 46 are fixed on the shaft 41. To this end there is a raised portion 43 and a key 44. The sheave 40 is rotatably and axially shiftably mounted on the shaft 41. In FIG. 3 the sheave 40 is provided with a self-lubricating bronze journal. It can also be provided with a needle bearing since the necessary axial shifting is only very slight.
The sheave 40 lies with its right side on the brake pad 46. On its left side are three spring washers 45 which are braced against a two-part counterpressure disc 60.
The counterpressure disc is made in two parts so that
1. In production the proper value of transmitted torque can be set,
2. During mounting the blackboard can be released for weight equalization, and
3. Finally again, the exact torque transmission can be set.
The tw
REFERENCES:
patent: 2215021 (1940-09-01), Vallen
patent: 3117767 (1964-01-01), McLean et al.
patent: 3134273 (1964-05-01), Wardlaw
patent: 3193254 (1965-07-01), Minnick
patent: 3848852 (1974-11-01), Therkildsen
patent: 3921925 (1975-11-01), Sarfati et al.
patent: 4118013 (1978-10-01), Christison et al.
patent: 4171594 (1979-10-01), Colanzi
Jillions John M.
Ross Karl F.
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