Crawling carriage

Claim 2

A carriage and track combination comprising: a. a track unit with side parts defining undercut zones that constitute a pair of guide ways; b. a carriage having a framework; c. drive roller means coupled to the framework and arranged in rolling engagement with the track unit; d. A motor coupled to the framework and operatively connected to the drive roller means for selectively causing movement of the drive roller means over the track unit; e. a pair of swing arms pivotally coupled to opposing sides of the framework; f. idler wheel means secured to the swing arms and positioned below the drive roller means for movement into rolling engagement with the pair of guide ways; g. locking means for tightening the swing arms and thereby simultaneously forcing the drive roller means against the track unit and the idler wheel means against the guide ways h. a cross framework coupled to an outside portion of said framework; i. a slide and way system interconnecting said framework and the cross framework; and, j. a reversible motor mounted to said framework and drivingly engaged with the slide and way system and arranged to shift the cross framework back and forth laterally relative to the path of movement of said framework, whereby the carriage may be caused to crawl along the track unit with the drive roller means exerting force against the track unit in one direction and the idler wheel means exerting force against the track unit in the opposite direction and whereby the cross framework may be caused to shift back and forth across the path of movement of the carriage.

Claim 3

The structure according to claim 1 wherein: the drive roller means includes dual and tandemly aligned drive rollers; and, the idler wheel means includes single idler wheels secured to corresponding swing arms and positioned centrally of the dual drive rollers.

Claim 4

The structure according to claim 1 wherein: the drive roller means includes a single drive roller; and, the idler wheel means includes a set of idler wheels coupled to each swing arm, each set having a pair of idler wheels on opposite sides of the single drive roller axis.

Claim 5

The structure according to claim 1 wherein the drive roller means includes: a flexible covering to improve traction with the track unit.

Claim 6

The structure according to claim 4 wherein: a plurality of resilient 0-rings are arranged in side-by-side relationship substantially across the drive roller means.

Claim 7

The structure according to claim 1 wherein: the tract unit is of generally annular shape and includes mating split ring sections that are detachably fastened together.

Claim 8

The structure according to claim 6 wherein the track unit inclUdes: a pedestal; and, a hub connected to the pedestal, having a generally circular opening for accommodating a tubular workpiece.

Claim 9

The structure according to claim 6 including: clamping means with at least three adjustable and substantially equiangularly spaced centering pads that extend radially through the split ring sections.

Claim 10

The structure according to claim 6 wherein: locating pins and apertures are positioned at mating end portions of the split ring sections to assist in orienting and fitting them together; the split ring sections are detachably fastened together with bolts extending through the mating end portions of the split ring sections, and, the upper surface portion of the pedestal is roughened to improve traction between the drive roller means and track unit.

Claim 11

The structure according to claim 1 wherein: the swing arms straddle the track unit and are pivoted to swing laterally inwardly toward the framework to facilitate positioning the idler wheels beneath the track unit side parts.

Claim 12

The structure according to claim 1 wherein the locking means includes: a pair of locking slots formed in the framework; a pair of tie bolts pivotally connected to corresponding swing arms and having free ends that extend through corresponding locking slots; and, tightening elements connected to the tie bolts free ends for regulating the holding force exerted by the drive roller means and idler wheel means against the track unit.

Claim 13

The structure according to claim 11 including: compensating means coupled to the locking means and arranged to allow slight displacement by the idler wheel means upon encountering irregular surface conditions on the track unit.

Claim 14

The structure according to claim 12 wherein the compensating means includes: a pair of coil springs which act as take up elements and are positioned over the tie bolts and between the locking slots and tightening elements.

Claim 15

The structure according to claim 1 wherein: the motor has a power take-off shaft; and, a slip clutch mechanism is positioned between the motor and drive roller means, structured to cause slippage when a predetermined torque is exerted on the power take-off shaft.

Claim 16

The structure according to claim 14 including: a gear train interconnecting the power take-off shaft and drive roller means; a spur gear of the gear train coupled to the power take-off shaft and having an outer face aimed away from the motor that is formed with a diametrical slot and, a drive pin extending transversely through the power take-off and normally spring loaded and drivingly engaged within the diametrical slot, wherein when the predetermined torque level is achieved the drive pin will be urged in and out of the diametrical slot to slip across the spur gear outer face.

Claim 17

The structure according to claim 15 including: a pair of diametrical cross slots in the spur gear outer face, and, a helical spring on the power take-off shaft, extending between a fixed point and the other face of the spur gear to normally hold the drive pin in one of the cross slots.

Claim 18

The structure according to claim 1 including: pipe welding means mounted to the carriage.

Claim 19

The structure according to claim 17 wherein the pipe welding means includes: a welding torch connected to one side of the carriage; a wire positioner connected to the same side of the carriage; and, filler wire feeder means for supplying filler wire through the wire positoner and to the welding torch.

Claim 20

A carriage and track assembly in combination with a pipe welding means comprising: a. a track unit including a pedestal of substantially constant width, the pedestal having side parts of substantially constant depth and which define undercut zones said track unit being of generally annular shape and including mating split ring sections that are detachably fastened together, the track unit includIng a hub connected to the pedestal having a generally circular opening for accommodating a tubular work piece to be welded, and clamping means having at least three adjustable and substantially equiangularly spaced centering pads that extend radially through the split ring sections; b. a central path of movement defined by an outer surface portion of the pedestal; c. a pair of guide ways defined by the undercut zones; d. a carriage for carrying said pipe welding means and including a framework; e. dual drive rollers coupled to the framework and arranged in rolling engagement against the central path portion of the pedestal; f. a motor coupled to the framework and operatively connected to the drive rollers for selectively causing movement of the drive rollers along the central path; g. a pair of swing arms pivotally coupled to opposing sides of the framework, said swing arms being oriented to straddle the track unit and swing laterally inwardly towards the framework; h. idler wheels secured to corresponding swing arms for movement into rolling engagement with corresponding guide ways at positions central of the dual drive rollers; and i. locking means operable to tighten the swing arms and thereby simultaneously force the dual drive rollers against the track unit and the idler wheels against the guide ways; wherein the carriage may be caused to crawl along the track to follow an orbital path with the drive rollers exerting force against the track in one direction and the idler wheels exerting force against the track unit in the opposite direction as the welding means traverses a weld joint.

Claim 21

A carriage and track assembly in combination with a pipe welding means comprising: a. a track unit including a pedestal of substantially constant width, the pedestal having side parts of substantially constant depth and which define undercut zones said track unit being of generally annular shape and including mating split ring sections that are detachably fastened together, the track unit includIng a hub connected to the pedestal having a generally circular opening for accommodating a tubular work piece to be welded, and clamping means having at least three adjustable and substantially equiangularly spaced centering pads that extend radially through the split ring sections; b. a central path of movement defined by an outer surface portion of the pedestal; c. a pair of guide ways defined by the undercut zones; d. a carriage for carrying said pipe welding means and including a framework; e. dual drive rollers coupled to the framework and arranged in rolling engagement against the central path portion of the pedestal; f. a motor coupled to the framework and operatively connected to the drive rollers for selectively causing movement of the drive rollers along the central path; g. a pair of swing arms pivotally coupled to opposing sides of the framework, said swing arms being oriented to straddle the track unit and swing laterally inwardly towards the framework; h. idler wheels secured to corresponding swing arms for movement into rolling engagement with corresponding guide ways at positions central of the dual drive rollers; and i. locking means operable to tighten the swing arms and thereby simultaneously force the dual drive rollers against the track unit and the idler wheels against the guide ways; wherein the carriage may be caused to crawl along the track to follow an orbital path with the drive rollers exerting force against the track in one direction and the idler wheels exerting force against the track unit in the opposite direction as the welding means traverses a weld joint.

Claim 22

The structure according to claim 19 including a cross framework coupled to an outside portion of said framework; and oscillating means for selectively shifting the the cross framework laterally relative to the path of movement of said framework, the oscillating means including a slide and way system interconnecting said framework and cross framework, and, a reversible motor mounted to the framework and drivingly engaged with the slide and way system and arranged to shift the cross framework back and forth; and, a fillar wire feeder means for supplying filler wire through the wire positioner and to the welding torch.