US 1692735 A
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Description (OCR text may contain errors)
Nov. 20, 1928. 1,692,735
B. HEGER ELECTRO, MOTOR Filed Feb. 16, 1925 I llilil n, W t
Patented Nov. 20, 192 8 UNITED STATES 3.16mi nnenn, or vnsran AKER, NEAR osLo, nonwaY.
Application filed February 16, 1925, Serial No. 9,691, and in Norway Kay 14, 1924.
My invention relates to improvements in el'ectromotors, especially in their connection with working machines.
In' electromotors which are to be used for driving working machines and tools through the medium of a centrifugal friction-clutch or other friction-clutch certain drawbacks are frequently observed.
Thus it is diflicult to arrange the motor for driving a tool as for instance a circular saw blade, a grinding disc or the like, without arranging special bearings for the latter outside the motor, which in addition to the increased cost of installation there is also the disadvantage of occupying a large part of the available space.
The purpose of my invention is to avoid these drawbacks by mounting the two parts of a centrifugal friction-coupling, on parts which are already present in the motor proper, viz: on the rotor and on the motor shaft respectively, the armature being mounted ina known manner loosely on the shaft, so that. it can rotate idly about it, but on obtaining a certain velocity is locked to said shaft by aid of the coupling.
In the following the invention shall be described with reference to the accompanying drawings, in which Fig. 1 is a sectional View of an electro-motor showing the general ar-' rangement of the same without detailing the' coupling arrangement. Fig. 2 is a sectional view in larger scale showing the details of the coupling arrangement.
5 The electro-motor may be of any kind, but
it is preferably arranged as an induction motor. Referring to Fig. 1' the armature 1- of the motor is mounted rotatably in relation to the shaft 2 by means of intermediate ball bearings 3.
At one or both ends of the armature one part 4 of a centrifugal friction-coupling with friction members 5 is attached by casting, by screws or in some other manner, said members cooperating with the other part 6 of the coupling. The latter part is cast integral with or attached to a sleeve 7 keyed to the shaft 2. Between the sleeve 7 and the motor housing 8 bearings 9 are arranged. The working tool is mounted on the shaft trunnion projecting out through the motor housing. In the constructional form ,shown in Fig. 1 the electromotor is assumed to be used for a double cirhousing.
cular saw with saw blades 10 and 11 mounted on the shaft trunnions 12and 13, respectively.
The clutch part 4 may, as shown in-the drawing, be constructed as a fan, it being provided with fan blades .14. In the other clutch part openings 15 for air circulation are provided.
In the constructional form illustrated the clutch member 4 which is attached to the armature by screws or the like, serves at the same time as a cover for the ball bearings 3.
The centrifugal friction coupling will be automatically'coupled in as soon as the armature has attained a certain velocity and likewise automatically coupled out when the load exceeds a predetermined limit, but as illustrated in Fig. 2 is arranged for being coupled in and out at will, it has the part 4 of the friction clutch fastened to the armature 1 and the other part 6 keyed to the shaft 2. The friction members 5 are linked to the part 4 by aid of links 16 fastened to levers 17, journalled to the coupling part 4 by aid of hinge bolts .18. The part 4 is surrounded with a coupling ring 19, slidable on the part 4 by the intermediary of a handle 20 on a lever 21, turnable about a hinge bolt 22 in the motor The rin 19 has a ring shaped groove into which the ends of the levers 17. The upper wall of the ring shaped groove has a cam face 23, adapted to engage the ends of the levers 17. In the position shown in Fig. 2 the levers 17 are free to swing out to let the friction members 5 engage I the opposite friction face of the friction part 6, but if by aid of the handle 20 the ring 19 is moved to the right, its cam face 23 will depress the ends of the levers 17, thereby withdrawing the friction members 5 from their contact with the part 6 and coupling out the shaft 2.
Through this arrangement is obtained that I may keep the centrifugal friction members lifted ofi until the rotor has obtained approximately its full speed, and by thereupon releasing them enable them to establish with-' out any greater amount of slipping coupling connections with the combined motor and working shaft, thereby reducing the current shocks due to the coupling in of the driven shaft to a minimum.
In an electric motor having its rotor loose- 1y mounted on the motor shaft, a centrifugal friction coupling adapted to interconnect said rotor and said shaft on said shaft attaining a predetermined speed comprising a two part coupling having one part fixedly mounted on the rotor and the other part fixedly mounted on the shaft Within the motor housing, said members adapted to friotionally engage one another, a handle extending through the eas- BJGRN HEGER.