US2120792A - Crane drive - Google Patents

Description

June 14, 1938.

G.` W. YANNEY CRANE DRIVE Filed June 17, 1936 2 Sheets-Shag?. 1

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INVENTOR June 14, 1938. G. w. YANNEY CRANE DRIVE Filed June 17, 193s 2 Sheets-Sheet 2 25 INVENTOR ,MM/M' Patented June 14, 1938 UNITED STATES rATENT OFFICE The Alliance Machine Company,

Alliance,

Ollio, a corporation of Ohio Application June 17,

8 Claims.

This invention relates to a drive for cranes and similar structures, and particularly for cranes of the bridge and gantry type.

It is customary to drive gantry cranes by a 5 pinion at the foot of each supporting trestle, co-

operating with racks mounted alongside the track rails on which the wheels supporting the crane travel. A so-called squaring shaft, including vertical shafts, a horizontal cross shaft and suitable bevel gearing, connects the drive pinions so that they move in synchronism and maintain the longitudinal axis of the crane precisely perpendicular to the track rails at all times.

Occasionally, because of local conditions, it is desirable that a crane traverse a path including a curved portion. It is an object of this invention to provide a drive for a bridge or gantry crane adapted to traverse curved paths whereby the longitudinal axis of the crane is maintained in a true radial position at all times while the crane is traversing the curved portion of its path. In accordance with my invention, I provide, in addition to the usual racks along the straight portions of the path and the driving p-inions on the crane trestle cooperating therewith, an additional rack along the curved portion of the track, at the outside thereof, and an additional pinion on the crane at the, end thereof on the outside of the curve, for meshing with said last-mentioned rack. This rack and pinion have a greater tooth pitch than the racks along the straight portions of the track, and the pinions cooperating therewith. The additional pinion is driven by the same mechanism which drives the usual pinions and moves at the same angular velocity as the latter. It is preferably spaced axially from the usual driving pinion on the end of the crane adapted to traverse the outside of the curve.

For a complete understanding of the invention, reference may be had to the accompanying drawings which illustrate a present preferred embodiment.

In the drawings,

Fig. 1 is a diagrammatic plan view showing a gantry crane and a track along which it is adapted to travel, including straight and curved portions;

Fig. 2 is a partial side elevation of a crane;

Fig. 3 is a partial end View of one of the crane trestles, to enlarged scale;

Fig. 4 is a sectional View along the line IV-VI of Fig. 3; and

Fig. 5 is a View similar to Fig. 4 showing the drive for the opposite end of the crane.

1936, Serial No. 85,708

(Cl. E-29) Referring now in detail to the drawings, a gantry crane IIB comprises a bridge, a portion of which is shown at II, and supporting trestles I2 and I3. The lower ends of the trestles rest on sills I4 and I5, preferably composed of structural shapes fabricated according to well known designs. Four-wheel trucks I6 (see Fig. 3) are swivcled to each end of both sills and are adapted to travel along a track I'I. The track includes straight sections I3 and I9 connected by a curved section 2|), the track rails on the inside of the curve being indicated at 2| and those on the outside of the curve at 22. The points of tangency between the straight and curved portions of the track are indicated by the dot-and-dash lines I8 and I9'.

Racks 23 and 24 extend along the inside and outside rails 2| and 22, respectively, throughout the straight sections I8 and I9. A similar rack 25 extends along the inside rail 2| throughout the curved portion 2E! of the track. The racks 23, 24 and 25 may conveniently be disposed between the track rails 2| and 22 and supported in any convenient manner (not shown). The rack 25, of course, is simply a continuation of the racks 23 except that it is curved instead of straight as are the latter.

Referring now more particularly to Figs. 4 and 5, a driving motor 26 is mounted on each sill I4. By means of reduction gearing 21, each motor drives an intermediate shaft 28 journaled in suitable bearings 29 mounted on the sills I4. Pinions 3|) on the shafts 28 drive gears 3| keyed to driving shafts 32 journaled in suitable bearings 33 carried by the structural shapes forming the sill and indicated at 34. Pinions 35 are keyed to the shafts 32 and mesh with driving pinions 36 keyed to shafts 36a journaled in bearings 31 mounted in bearing brackets 38 suspended below the sills I4. The pinions 36 mesh with the racks 23, 24 and 25.

Vertical shafts 39 journaled in suitable bearings carried on the trestles I2 and I3 are driven from the shafts 28 by bevel gearing 40. The shafts 39 are connected by a horizontal cross shaft 4| extending therebetween and journaled in suitable bearings 42 carried on the bridge II, and bevel gearing 43. By this means, the driving pinions 36 move at the same angular velocity, even though each has its own driving motor, and the trestles I2 and I3 always move at the same speed, while traveling along straight stretches of track. This maintains the longitudinal axis of the crane precisely perpendicular to the track rails, and prevents binding of the supporting wheels or derailment of the trucks I6.

As will be seen by comparison of Figs. 4 and 5, the drives for the two ends of the crane are identical to a large extent. The drive for the end of the crane adapted to traverse the outside of the curved portion 20 of the track, however, is provided with an additional driving pinion 44 keyed to the shaft 36a on which the pinion 36 is mounted. The pinion 44 is thus spaced axially from the pinion 35 for cooperation with a rack' 45 extending throughout the curved portion of the track along the outside rails. The pinion 44 has a greater diameter than the pinions 36, but has the same number of teeth which means simply that pinion 44 has a greater tooth pitch than pinions 36. The rack 45 diiiers similarly in pitch from the racks 23, 24 and 25. Since the pinion 44 is mounted on the same `shaft as the pinion 36 at the end of the crane traversing the outside of the curve, the pinion144 will make one revolution for every revolution of the pinions 36. The pinion 44, however, when it engages the rack 45, as the crane moves from either of the straight portions or tangents I8 and I9 onto the curved portion 20 of the track, will cause the end of the crane traversing the outside of the track to move at a linear speed greater than that at which the end of the crane on the inside of the curve moves. The difference between the diameters of the pinions 44 and 36, of course, is dependent on the curvature of the curved portion 20 of the track and may easily be determined mathematically. As a result of the construction described, the end of the crane on the outside of the curve moves faster than the end on the inside, so as to traverse the greater length of the track rails 20 on the outside of the curve in the same time that the inner end of the crane traverses its shorter length of curved track rail. The longitudinal axis of the crane is thereby maintained in a true radial position relative to the curved track portion at all times While traversing the curve.

It will be observed that the racks 23 and 24 terminate at the ends of the rack 45.V The transition from the straight portion of the track to the curved portion, or vice versa, is thereby easily made. The racks 24 and 45 overlap the lines I8' and I9 dening the curved portion 20 of the track because the driving shaft 36a is not disposed centrally of the trestle I2, but oit-center thereof, adjacent one leg of the trestle as shown in Fig. 3. By this arrangement, the change from either of the racks 24 to the rack 45 is made precisely at the time the central vertical plane through the crane passes the boundary lines I8' and I9. r

It will be clear from the foregoing description that the invention makes it feasible to operate bridge or gantry cranes over tracks including curved portions. The limitation in the movement of bridge or gantry cranes to straight paths is thus removed. A crane may even be caused to traverse a reverse curve by providing the additional rack on the outside of each curve and the additional driving pinion on both ends of the crane. To meet such conditions, it would only be necessary to substitute the structure of Fig. 5 for that shown in Fig. 4.

Although I have illustrated and described herein but'one preferred embodiment of the invention, it will be apparent that changes in the construction disclosed may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. The combination withV a crane having supporting wheels spaced axially from each other and adapted to traverse track rails having a curve therein, of means for driving the crane along the rails, including means for driving the end of the crane on the outside of the curve at a linear speed greater than that of the end of the crane on the inside of the curve whereby to maintain the crane in a truly radial position at all times while traversing the curve.

2. The combination with a crane having supporting wheels spaced axially from each other and adapted to traverse track rails having a curve therein, of means for driving the crane along the rails, and means eiective when the crane traverses the curve, to drive the end of the crane on the outside of the curve at a higher linear speed than the end of the crane on the inside of the curve.

3. A gantry crane having supporting trestles at each end, track Wheels at the foot of each trestle, adapted to traverse a track having straight and curvedportions, a driving pinion carried on each trestle for cooperation with fixed racks extending along the straight portions, of the track, means for driving the pinions concurrently at the same speed, a rack on the outside of the curved portion of the track having a tooth pitch greater than that of the racks along the straight portions of the track, and a pinion on the trestle traversing the outside of the curved portion of the track adapted to mesh with said last-mentioned rack, said last-mentioned pinion also being driven by said driving means.

4. A drive for a movable structure having supporting wheels spaced axially apart and adapted to traverse a path having straight and curved portions, comprising a rack adjacent one end of the structure extending along the straight and curved portions of said path, a second rack adjacent the other end extending along the straight portion only of the path and terminating at the curved portion thereof, pinions of the same size and pitch journaled in said ends meshing with said racks, means for driving said pinions at the same angular velocity, a third rack extending along the curved portion only of said path at the same end of the structure as said second rack, and a, pinion meshing with said third rack and connected with said rst mentioned pinions so as to rotate .at the same angular velocity but having a pitch different from that of the rst mentioned pinions.

5. An elongated wheeled structure move/ble sidewise along a path including straight and curved portions having driving pinions mounted on each end meshing with xed racks, one of which terminates at said curved portion, means connecting the pinions whereby they operate to move both ends of the structure at the same Speed while traversing said straight portion, a rack along said curved portion, and a pinion on said structure meshing therewith when the latter reaches` said curved portion, said last mentioned rack and pinion being eiective to move one end of said structure at a lineal speed different from that at which the other end is moved by its rack and pinion.

6. The apparatus defined by claim 5, characterized by said last mentioned rack and pinion having a tooth pitch differing from that of the first mentioned racks and pinions.

7. A crane movable along rails, having a drive comprising driving pinions on both ends of the crane cooperating with fixed spaced racks adjacent said rails, means connecting said pinions whereby to move both ends of the crane at the same speed, and an additional rack adjacent a curve in the rails and a third pinion journaled on one end of the crane to cooperate with said additional rack for driving said end of the crane at a linear speed different from that at which the other end is driven to maintain the crane radial when traversing said curve, the rst mentioned rack on the end adjacent said additional rack 8. An elongated movable structure having driving pinions at both ends cooperating with xed spaced racks, said pinions being connected by a squaring shaft, and an additional pinion cooperating with a further fixed rack lying along a curved portion of the path of the structure to move the end thereoi on the outside of the curved portion at a greater linear speed than the end on the inside, the rst mentioned rack on the end adjacent the additional rack terminating Where the latter begins.

GEORGE W. YANNEY.

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