Self-energizing rail clamp

Claim 2

In combination with a truck for a wheeled rail vehicle movable along a runway rail, wherein the rail includes a tie flange, a web upstanding from the flange, and a railhead on top of the web, a rail clamp coacting with the railhead for clamping the truck to the rail comprising, a frame having first clamp means engagable with the underside of the railhead and second clamp means movable relative said first clamp means and engagable with the upperside of the railhead, one of said clamp means including a plurality of tiltable mounted sprags, means mounting the frame for limited vertical movement such that when the clamp is de-energized said first clamp means clears the underside of the railhead and said second clamp means clears the upperside of the railhead, means mounting said first clamp means to said frame to move therewith, high mechanical advantage means mounting said second clamp means on said frame such that both clamp means are movable to engage the railhead upon actuation thereof and apply a squeezing force thereto when the mechanical advantage means is actuated wherein the sprags produce a locking wedging action with the railhead, and means for actuating said high mechanical advantage means.

Claim 3

The rail clamp of claim 1, wherein said first clamp means includes means engaging the underside of said railhead at opposite sides of the web.

Claim 4

The rail clamp of claim 1, wherein said first clamp means includes at least one pair of hook-shaped coacting jaws having a pair of rail engaging faces for engaging the underside of the railhead.

Claim 5

The rail clamp of claim 1, wherein said first clamp means includes two pairs of hook-shaped coacting jaws, each having a pair of rail engaging faces for engaging the underside of the railhead, one pair of jaws being positioned on each side of said second clamp means.

Claim 6

The rail clamp of claim 1, wherein said second clamp means includes a housing and the plurality of sprags carried thereby and engagable with the railhead when the clamp is energized.

Claim 7

The rail clamp of claim 5, wherein said housing includes means mounting said sprags to cause tilting in a direction away from a force being applied to the clamp to increase the frictional engagement between the clamping members and the railhead.

Claim 8

The rail clamp of claim 6, wherein said housing includes means associated with the sprags to provide proper clamping action while compensating for a variance in railhead depth.

Claim 9

The rail clamp of claim 7, wherein said compensating means includes a movable sprag bearing plate carried on the housing and engaging the upper ends of the sprags, and elastomeric means interposed between the bearing plate and the housing.

Claim 10

The rail clamp of claim 1, and means mounting the frame to a bracket support means, wherein said means mounting the frame to the bracket support means includes trunnion means on said frame received in vertical slot means formed in said bracket support means.

Claim 11

The rail clamp of claim 1, and stop means controlling the displacement of said high mechanical advantage means.

Claim 12

The rail clamp of claim 10, wherein the stop means is adjustable to control the maximum clamping force of the clamp.

Claim 13

The rail clamp of claim 11, wherein the means for actuating the high mechanical advantage means includes a weighted self-energizing actuating arm, and power means for lifting the arm to de-energize the clamp.

Claim 14

The rail clamp of claim 1, wherein said high mechanical advantage means is a toggle linkage mechanism.

Claim 15

The rail clamp of claim 1, wherein said high mechanical advantage means is a cam drive mechanism.

Claim 16

In combination with a truck for a traveling crane movable along a runway rail, wherein the rail includes a tie flange, a web upstanding from the flange, and a railhead on top of the web, a rail clamp for locking the truck to the rail by clamping frictionally to the top and bottom surfaces of the railhead comprising a clamp head, at least one pair of coacting jaws extending From the head and engagable with the underside of the railhead, a self-energizing sprag head on the clamp head movable toward and away from the topside of the railhead and causing the jaws to synchronously move toward and away from the underside of the railhead to apply a squeezing force thereto when the sprag head is energized wherein the sprag head produces a locking wedging action with the railhead, said sprag head including a plurality of tiltable mounted sprags, and means for de-energizing the clamp.

Claim 17

In combination with a truck for a traveling crane movable along a runway rail, wherein the rail includes a tie flange, a web upstanding from the flange, and a railhead on top of the web, a rail clamp for locking the truck to the rail by clamping frictionally to the top and bottom surfaces of the railhead comprising a clamp head, at least one pair of coacting jaws extending From the head and engagable with the underside of the railhead, a self-energizing sprag head on the clamp head movable toward and away from the topside of the railhead and causing the jaws to synchronously move toward and away from the underside of the railhead to apply a squeezing force thereto when the sprag head is energized wherein the sprag head produces a locking wedging action with the railhead, said sprag head including a plurality of tiltable mounted sprags, and means for de-energizing the clamp.

Claim 18

A rail clamp mountable on a truck of a traveling crane movable along a runway rail to anchor the crane at any selected position to counter wind forces, wherein the rail includes a head having an upper wheel engaging surface and opposed undersurfaces, said rail clamp including a pair of hook-shaped clamping members for extending around the railhead and engaging the under-surfaces thereof at spaced points along the railhead and a sprag clamping member for engaging the upper rail surface at a point intermediate the points of engagement by the hook-shaped members, a pair of spaced bracket supports carried by the crane truck, an inverted U-shaped frame between the brackets including an upper cross bar and downwardly extending legs, means mounting the frame to the brackets for limited vertical movement therewith, said hook-shaped clamping members being carried on the legs of said frame and said sprag clamping member being arranged between the legs, a toggle linkage means between the frame and sprag clamping member, an actuating arm extending laterally from the toggle linkage means, a weight on said actuating arm to actuate said toggle linkage means and energize the clamp, and means connected to the actuating arm for de-energizing same.

Claim 19

A rail clamp mountable on a truck of a traveling crane movable along a runway rail to anchor the crane at any selected position to counter wind forces, wherein the rail includes a head having an upper wheel engaging surface and opposed undersurfaces, said rail clamp including a pair of hook-shaped clamping members for extending around the railhead and engaging the under-surfaces thereof at spaced points along the railhead and a sprag clamping member for engaging the upper rail surface at a point intermediate the points of engagement by the hook-shaped members, a pair of spaced bracket supports carried by the crane truck, an inverted U-shaped frame between the brackets including an upper cross bar and downwardly extending legs, means mounting the frame to the brackets for limited vertical movement therewith, said hook-shaped clamping members being carried on the legs of said frame and said sprag clamping member being arranged between the legs, a toggle linkage means between the frame and sprag clamping member, an actuating arm extending laterally from the toggle linkage means, a weight on said actuating arm to actuate said toggle linkage means and energize the clamp, and means connected to the actuating arm for de-energizing same.

Claim 20

The rail clamp of claim 16, wherein means is provided to limit the displacement of the toggle linkage to thereby limit the maximum force applied by the clamp.

Claim 21

The rail clamp of claim 17, wherein said displacement limiting means is adjustable.

Claim 22

The rail clamp of claim 17, wherein means is provided between the sprag clamping member and the toggle linkage means to define a resilience such that the toggle linkage means can assume a high force, nearly straight configuration, even though variations in railhead depth are encountered along the length of the rail.

Claim 23

The rail clamp of claim 19, wherein said sprag clamping member includes a plurality of upstanding side-by-side disc-like hardened sprags aligned with the railhead and extending transverse thereto, and means for tilting the sprags in the event a force is applied to the clamp to increase the frictional engagement with the railhead.

Claim 24

The rail clamp of claim 17, wherein said sprag clamping member includes an inverted U-shaped housing having an upper cross plate and downwardly extending side plates, a plurality of upstanding, rectangular in cross section, side-by-side, disc-like hardened sprags aligned with the railhead and extending transverse thereto arranged between the side plates, a bearing plate positioned between the side plates and below the cross plate for engagement with the upper ends of the sprags and mounted to the cross plate for limited vertical movement therewith, means between the cross plate and bearing plate exerting a force to bias said plates apart, and means at the side plates engaging said sprags when the clamp is energized and a force is applied to the clamp along the rail to tilt the sprags in a direction away from the force, thereby increasing the distance between the railhead and the bearing plate to ultimately bottom the bearing plate on the cross plate and increase the frictional resisting forces applied by the clamp.

Claim 25

The rail clamp of claim 16, wherein said hook-shaped clamping members include coacting jaws one on each side of the rail, and means for selectively moving the jaws into rail engaging position during energization of the clamp and out of rail engaging position to allow removal of the clamp from the rail.