US2391956A - Limit stop for gun mounts - Google Patents

Description

Jan. I, 1946.

F. C. EASTMAN LIMIT STOP FOR GUN MOUNTS 2 Sheets-Sheet 1 Filed March 23, 1944 Jan. 1, 1946.

F. C. EASTMAN LIMIT STOP FOR GUN MOUNTS Filed March 25, 1944 2 Sheets-Sheet 2 [nuenior Fredfaqzman Patented Jan. 1, 1946 LIMIT STOP FOR GUN MOUNTS Fred C. Eastman, Marblehead, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J a corporation of New Jersey Application March 23, 1944, Serial No. 527,854

4 Claims.

This invention relates to means for limiting the extent of angular movement of devices and is herein illustrated as applied to a gun mount a swinging movement of which is effected by a rotatable driven member.

When guns are supported for movement so that the gunner may train them on a target and are mounted so as to project through an opening in an enclosure such, for example, as through a fixed opening in an airplane, some means must be provided to limit the extent of their swinging movement in order to prevent the guns from damaging the plane as by contact with the frame of the opening. The necessity for such limitation of movement becomes increasingly more important as larger and larger guns are being thus used in view of the relatively light structure of the so-called skin of the plane. It is evident, too, that, when the swinging movement of the gun is produced by a power-driven member, the use of an ordinary bumper stop might well be ineifective in case of an accident such that the power drive is still effective after contact of the gun with the sides of, or the frame around, the opening.

An object of the invention is to provide an improved limit stop for power-operated movable members which shall also be effective to brake the power-driven member which causes the movement, thus overcoming both the inertia of the movable member and the force of the power drive.

A feature of the invention resides in the employment of brakes movable with the member to be stopped and positioned for engagement with the power-driven member which causes the movement so that they also act as stops. In the illustrated arrangement, the power-driven member is a rotatable pinion having a grooved portion, and the limit stop is an arcuate brake member, wedge shaped in cross-section, which is positioned for engagement with the grooved portion as a bumper and in the groove of said driven member as a brake.

These and other features of the invention will best be understood from a consideration of the following specification taken in connection with the accompanying drawings, in which Fig. 1 is an angular view of a gun, mounted for swinging movement in azimuth as well as in elevatign, to which the novel stops have been applie Fig. 2 is a detail view, on a larger scale and partly in section, showing one of the limit stops in engagement with the grooved portion of the power-driven member;

Fig. 3 is a fragmentary view of the parts shown in Fig. 2 and taken at right angles thereto;

Fig. 4 is a diagrammatic view, on a larger scale, showing one of the motor drives and the stops associated therewith; and

Fig. 5 is a detail view, on the scale of Fig. 4, looking at the end of one stop and showing how it is supported on a driven segment.

A gun It! is arranged for movement in elevation by being pivoted in the side frames I4 and 15 of a swingable gun mount or yoke which, in turn, is adapted to be turned about a vertical axis so that the gun may be trained in azimuth. The gun trunnion on the near side (not shown) supports a plate l2 having a stud [3 received in a bearing carried by a plate l5 which slides horizontally into a groove formed in the side frame 14 and is clamped there. The gun trunnion on the far side (not shown) supports a segment gear l8 which is bolted to the gun and has a similar stud and bearing connection to the side frame It. 'The yoke is completed by top and bottom. cross members 20 and 22. Of these, the cross. member 20 is pivoted to the supporting structure in which the gun is mounted, by a top bearing 24, while the lower cross member 22 is received in bearings 25 above a segment gear 26 secured to a cross beam 28 representing part of the structure in which the gun is mounted. To-and-fro movement of the gun in azimuth is efiected by a powerdriven pinion 30 meshing with the segment gear 26 and having rotatable with it, and secured to or integral with it, a cylindrical, pulley-like portion 32 provided with a tapered groove 34 (Fig. 3)

On the segment gear 26 (Fig. 1), are fastened elongated limit stops 3B and 38 which are spaced by a distance representing the permissible swing of the gun mount in azimuth. Each of these comprises a casing 40 (Fig. 2) having a flange 42 carrying dowel pins 44 and a clamp screw 46 to secure the stop to the segment. In this casing there is a plunger 50 provided with an arcuate portion 52 the edge of which is tapered at 54 (Fig. 3) to fit the groove 34 of the driven member and thereby to act as a brake as well as a stop. A loaded spring 56 is compressed in the casing 40 behind the plunger 50, and the limit of outward movement of the plunger is determined by a stem 58 having a stop nut 60. Tilting of the gun in elevation is effected by a driven pinion 64 meshing with the segment gear 18 on the gun. Associated with the grooved portion 65 of this pinion and mounted on the segment gear l8, there are limit StOps 66 and 68, the construction of which is identical with those shown in Fig. 2. At the junction between the plunger 50 and the arcuate portion 52 of each stop 36, 38, 66 and68, are wings 61 joined at one end and provided with a notch 69 (Fig. slidably engaging the edge of its associated flange 42 to hold the elongated arcuate' portions in alignment with and ready to enter the groove in the pulley-like portion of its associated pinion 3D, 64.

One method of driving these pinions 30 and 64 is illustrated diagrammatically in Fig. 4 wherein there are shown the connections for the motor which drives the pinion 30. This motor, mounted on a casing 12 (Fig. 1) attached to the side frame M, has a worm-and-gear connection 14 to a jack shaft 16 which has a similar connection 78 to a vertical shaft 80. On the lower end of thisshaft 80 is the pinion 30 meshing with the ,teeth of the segmental gear 26. If desired, the control of the motor 10 and of the corresponding motor (not shown) which drives the pinion 64 may be effected from a distance with the assistance of Selsyn transformers '82 and 84 which may be associated with a remote-control system of the type disclosed in the patent to Hewlett et 'al. No. 1,626,824, granted May 3, 1927, or they may be connected in any other desired fashion.

In the operation of the drive, it will be seen that, when a swinging member reaches the limit of desired movement, the arcuate portion 52' of a limit stop will enter the groove 34 of the member 32 which is attached to the driving pinion 30 and stop the movement. Inasmuch as this arcuate member is tapered, it will set up a very considerable braking friction with that member and quickly stall the driving motor associated with it. Since the arcuate braking member 52 is resiliently supported in its casing 40, there is an opportunity for the braking member to yield. At thesame time, however, the greater the yield of that member, the greater will be the compression of its spring 56 and hence the greater will be the braking force set up, and there will be little tendency to cause the limit stops to be broken from the segment gears on which they are mounted.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, a swingable support having a gear segment, a rotatable driven pinion meshing with the segment on said support, said driven pinion having a grooved portion, and a stop movable with said swingable support and positioned to engage the groove in said driven pinion to brake it and then positively to stop the rotation of the support. I

2.- In combination, a swingable support, a rotatable driven member for swinging said support, said driven member having a grooved portion, an elongated stop movable with said swingable support, and means for holding said stop in position to engage the groove in said driven member to brake the rotation thereof.

3. In combination, a support for an article, said support being swingable about an axis, a driven member rotatable about a parallel axis and having a driving connection to said support to swing it, said driven member having a portion provided with a tapered groove, and a stop carried by said swingable support and having a tapered arcuate member for engagement in said groove to brake the rotation thereof and then positively to stop thesupport at its limit of swinging movement.

4. In combination, a swingable support, a rotatable driven member connected to said support to swing it, said driven member having a portion provided with a tapered groove, a stop movable with said swingable support and having a tapered arcuate member for engagement in said groove to brake the rotation thereof at the limit of movement of the support, yielding means supporting said arcuate member on said stop, and slidably interengaging parts to hold said arcuate member alined with the groove of said driven member.

FRED C. EASTMAN.

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