WO2014172770A1

WO2014172770A1 - Pipe handling apparatus and method

Info

Publication number: WO2014172770A1
Application number: PCT/CA2013/000404
Authority: WO
Inventors: Nathan Crossley; Vince Morelli; Nicholas MORELLI; Kurtis KEEBLER
Original assignee: Custom Pipe Handlers Canada Inc.
Priority date: 2013-04-25
Filing date: 2013-04-25
Publication date: 2014-10-30

Abstract

A pipe handling apparatus including a base frame, a lift carriage with an elongated trough, and a forward lifting mechanism for raising and lowering a forward carriage end relative to the base frame. The pipe handling apparatus may also include a rearward lifting mechanism for raising and lowering a rearward carriage end relative to the base frame. The pipe handling apparatus may also include a skate apparatus for moving a pipe joint in both directions along the elongated trough. The pipe handling apparatus may also include lifting assemblies for lifting the pipe handling apparatus relative to a bearing surface. The pipe handling apparatus may also include an extendable and retractable ramp for moving objects to and from an elevated platform positioned adjacent to the pipe handling apparatus.

Description

PIPE HANDLING APPARATUS AND METHOD

TECHNICAL FIELD An apparatus and a method for delivering lengths of pipe to and from an elevated platform such as the floor of a drilling rig, a service rig or an offshore rig.

BACKGROUND OF THE INVENTION During operations at a drilling rig, a service rig or an offshore rig, it is frequently necessary to move lengths of pipe (referred to as pipe joints) between the rig floor and a pipe storage area adjacent to the rig.

A pipe joint may be moved to and from the rig floor by attaching a winch cable from a winch on the rig to the pipe joint and then raising or lowering the pipe joint using the rig winch. This procedure is time consuming and potentially dangerous for the rig crew.

Various apparatus and methods exist in the prior art which are directed at automating the procedure of moving pipe joints to and from the rig floor. A pipe handling apparatus of this type is frequently referred to as a "catwalk".

Some prior art pipe handling apparatus of the catwalk type and associated methods are described in U.S. Patent No. 4,386,883 (Hogan et al); U.S. Patent No. 4,403,898 (Thompson); U.S. Patent No. 4,494,899 (Hoang et al); U.S. Patent No. 6,994,505 (Hawkins); U.S. Patent No. 7, 163,367 (Handley); U.S. Patent No. 8,016,536 (Gerber et al); U.S. Patent No. 8,033,779 (Gerber et al); U.S. Patent No. 8,052,368 (Littlewood et al); U.S. Patent No. 8,215,887 (Fikowski et al); U.S. Patent Application Publication No. US 2005/0238463 (Smith); U.S. Patent Application Publication No. US 2008/0263990 (Morelli et al); U.S. Patent Application Publication No. US 201 1/0070054 (Crossley et al); U.S. Patent Application Publication No. US 2012/0027541 (Gerber et al); U.S. Patent Application Publication No. US 2012/0121364 (Taggart et al); Canadian Patent No. 2,224,638 (Morelli et al); Canadian Patent No. 2,431 ,213 (Handley et al); Canadian Patent No. 2,431 ,229 (Shiels et al); Canadian Patent No. 2,510,137 (Wells); Canadian Patent Application No. 2,476,109 (Smith); and Canadian Patent Application No. 2,713,676 (Crossley et al). SUMMARY OF THE INVENTION

References in this document to orientations, to operating parameters, to ranges, to lower limits of ranges, and to upper limits of ranges are not intended to provide strict boundaries for the scope of the invention, but should be construed to mean "approximately" or "about" or "substantially", within the scope of the teachings of this document, unless expressly stated otherwise.

As used herein, "upper" and "lower" and "above" and "below" are relative to the normal orientation of the pipe handling apparatus during use. As one example, "lower" means relatively close to a bearing surface upon which the pipe handling apparatus rests and "upper" means relatively less close to a bearing surface upon which the pipe handling apparatus rests, so that "upper" is above "lower" relative to the bearing surface. As a second example, "above" means a direction away from the bearing surface and "below" means a direction toward the bearing surface.

As used herein, a "jacking device" includes any device which may be used to move two parts or elements relative to each other by increasing or decreasing a distance between two or more components of the jacking device.

The present invention is directed at a pipe handling apparatus and method.

In an apparatus aspect, the pipe handling apparatus is comprised of a base frame, a lift carriage, and at least one lifting mechanism for lifting the lift carriage relative to the base frame.

In a first exemplary apparatus aspect, the invention is a pipe handling apparatus comprising: (a) a base frame, wherein the base frame has a forward frame end and a rearward frame end;

(b) a lift carriage connected with the base frame, wherein the lift carriage is comprised of a forward carriage end, a rearward carriage end, and an elongated trough; and (c) a forward lifting mechanism for raising and lowering the forward carriage end relative to the base frame. The base frame may be comprised of any structure, device and/or apparatus or combination of structures, devices and/or apparatus which is capable of supporting the lift carriage and other components of the pipe handling apparatus. In some embodiments, the base frame may be constructed partly or entirely of steel structural members such as steel tubing. The lift carriage may be comprised of any structure, device and/or apparatus or combination of structures, devices and/or apparatus which is capable of supporting a pipe joint and which is capable of moving relative to the base frame. In some embodiments, the lift carriage may be extendable and retractable to enable the forward carriage end of the lift carriage to extend or retract relative to the base frame.

The lift carriage may be connected with the base frame either directly or indirectly in any suitable manner. In some embodiments, the rearward carriage end may be pivotably connected with the base frame. In some embodiments, the rearward carriage end may be slidably and pivotably connected with the base frame. In some embodiments, the rearward carriage end may be connected with the base frame such that the rearward carriage end is not capable of raising and lowering relative to the base frame. In some embodiments, the rearward carriage end may be connected with the base frame such that the rearward carriage end is capable of raising and lowering relative to the base frame. The elongated trough may be any size, shape or length which is capable of receiving the pipe joints which are to be handled by the pipe handling apparatus. In some embodiments, the elongated trough may be generally circular-shaped or arc-shaped. In some embodiments, the elongated trough may be generally V-shaped. The forward lifting mechanism may be comprised of any structure, device or apparatus or combination of structures, devices and/or apparatus which is capable of raising and lowering the forward carriage end relative to the base frame. The forward lifting mechanism may be driven in any suitable manner, including as non-limiting examples, mechanically, electrically, pneumatically and/or hydraulically. In some embodiments, the forward lifting mechanism may be comprised of a forward jacking device, wherein the forward jacking device may be driven in any suitable manner. As non-limiting examples, the forward jacking device may be driven mechanically, electrically, pneumatically and/or hydraulically. In some particular embodiments, the forward jacking device may be hydraulically driven.

In some embodiments, the forward lifting mechanism may be comprised of:

(i) a lower lifting member having a frame attachment end and a frame remote end, wherein the frame attachment end is pivotably connected with the base frame;

(ii) an upper lifting member having a carriage attachment end and a carriage remote end, wherein the carriage attachment end is pivotably connected with the lift carriage and wherein the carriage remote end is pivotably connected with the frame remote end of the lower lifting member; and

(iii) an extendible and retractable forward jacking device having a lower jack end and an upper jack end, wherein the lower jack end is pivotably connected with the lower lifting member at a location between the frame attachment end and the frame remote end, and wherein the upper jack end is pivotably connected with the upper lifting member at a location between the carriage attachment end and the carriage remote end.

The lower lifting member may be comprised of a single lower member or may be comprised of a plurality of lower members. The upper lifting member may be comprised of a single upper member or may be comprised of a plurality of upper members. In some embodiments, the lower lifting member may be comprised of a pair of lower members and the upper lifting member may be comprised of a pair of upper members.

The forward jacking device may be comprised of a single jacking device or may be comprised of a plurality of jacking devices. In some embodiments, the forward jacking device may be comprised of a pair of jacking devices.

In some embodiments, one of a pair of jacking devices may be associated with one of a pair of lower members and one of a pair of upper members, and the other of the pair of jacking devices may be associated with the other of the pair of lower members and the other of the pair of upper members, so that the forward lifting mechanism is comprised of a pair of identical or similar arrangements of a lower member, an upper member, and a forward jacking device.

In some embodiments, the forward lifting mechanism may be configured so that the frame remote end of the lower lining member and the carriage remote end of the upper lifting member are located between the forward jacking device and the rearward frame end. In other words, in some embodiments, the forward lifting mechanism may be configured so that the vertex between the lower lifting member and the upper lifting member is directed toward the rearward frame end.

The lift carriage may be comprised of a single section, or the lift carriage may be comprised of a plurality of stages. In some embodiments, a plurality of carriage stages may be extendable and retractable relative to each other so that the forward carriage end is extendable and retractable relative to the base frame.

In some embodiments, the lift carriage may be comprised of a first carriage stage and a second carriage stage. In some embodiments, the base frame may be connected with the first carriage stage and the second carriage stage may be comprised of the elongated trough.

The carriage stages may be extended and retracted relative to each other in any suitable manner, including as non-limiting examples, mechanically, electrically, pneumatically and/or hydraulically.

In some particular embodiments, the carriage stages may be extended and retracted relative to each other with a carriage chain drive. In some embodiments, the carriage chain drive may be hydraulically powered. In some particular embodiments, the carriage stages may be extended and retracted relative to each other with a carriage jacking device. In some embodiments, the carriage jacking device may be hydraulically powered.

In some particular embodiments, the carriage connection end of the upper lifting member of the forward lifting mechanism may be connected with the first carriage stage and the second carriage stage may be comprised of the elongated trough, and the second carriage stage may be extendable relative to the first carriage stage in a carriage extending direction away from the rearward carriage end and retractable relative to the first carriage stage in a carriage retracting direction toward the rearward carriage end. In some embodiments, the second carriage stage may be received within a track defined by the first carriage stage so that the second carriage stage slides within the track in order to extend and retract the second carriage stage relative to the first carriage stage.

In some embodiments, the pipe handling apparatus may be comprised of a skate apparatus which is adapted to engage with a pipe joint positioned in the elongated trough in order to move the pipe joint along the elongated trough, wherein the skate apparatus is movable along the elongated trough.

The skate apparatus may be moved along the elongated trough in any suitable manner, including as non-limiting examples, mechanically, electrically, pneumatically and/or hydraulically. In some particular embodiments, the skate apparatus may be moved along the elongated trough by a skate chain drive, which is driven by a drive motor. In some embodiments, the drive motor may be hydraulically powered.

In some embodiments, the skate apparatus may be comprised of a transverse pipe joint support for engaging with an end of a pipe joint so that the skate apparatus can push the pipe joint along the elongated trough. In some embodiments, the transverse pipe joint support may be comprised of a transverse plate which is configured to engage with an end of the pipe joint. In some embodiments, the transverse plate may be comprised of a wear pad.

In some embodiments, the skate apparatus may be comprised of a gripping mechanism which is adapted for gripping a pipe joint so that the pipe joint can be moved along the elongated trough by the skate apparatus while being gripped by the gripping mechanism. The gripping mechanism may be comprised of any structure, device or apparatus which is capable of gripping a pipe joint. In some embodiments, the gripping mechanism may be comprised of a first gripper section, a second gripper section and an actuatable gripper head operably connected with the first gripper section and the second gripper section. In some embodiments, the gripper head may be actuated between a pipe gripping position and a pipe release position by relative movement between the first gripper section and the second gripper section. In such embodiments, the gripping mechanism may be configured in any suitable manner which enables the gripper head to be actuated by relative movement between the first gripper section and the second gripper section.

In some such embodiments, the skate apparatus may be comprised of a mechanical gripper linkage for operably connecting the gripper head with the first gripper section and the second gripper section. The mechanical gripper linkage may be comprised of any suitable structure, device or apparatus or combination of structures, devices and/or apparatus. In some embodiments, the gripper head may be directly connected with one of the first gripper section or the second gripper section and the mechanical gripper linkage may be comprised of one or more linkage members for indirectly connecting the gripper head with the other of the first gripper section and the second gripper section.

In some such embodiments, the first gripper section may be reciprocably connected with the elongated trough, the second gripper section may be reciprocably connected with the elongated trough, and the first gripper section may be reciprocably connected with the second gripper section such that the first gripper section and the second gripper section are capable of reciprocating relative to each other along the elongated trough by an actuating amount of relative reciprocating movement. In some embodiments, the first gripper section and the second gripper section may each have a reciprocating resistance relative to the elongated trough, and the relative reciprocating movement between the first gripper section and the second gripper section may be facilitated by providing the first gripper section and the second gripper section with different reciprocating resistances.

In some embodiments, the reciprocating resistance of the second gripper section may be greater than the reciprocating resistance of the first gripper section so that the first gripper section reciprocates along the elongated trough more easily than does the second gripper section.

In some embodiments, the gripping mechanism may be configured so that the gripper head is actuated to the pipe gripping position by moving the first gripper section toward the rearward carriage end relative to the elongated trough, and so that the gripper head is actuated the pipe release position by moving the first gripper section toward the forward carriage end relative to the elongated trough. In some embodiments, the skate apparatus may be comprised of a lower pipe joint support for supporting a pipe joint while the pipe joint is engaged with the skate apparatus. In some embodiments, the lower pipe joint support may be comprised of a pipe shovel for scooping an end of a pipe joint from the elongated trough into engagement with the skate apparatus.

In some embodiments, the pipe shovel may have a forward shovel end, and the forward shovel end may be comprised of a tapered surface for assisting in scooping the end of the pipe joint from the elongated trough.

In some embodiments, the pipe shovel may have a rearward shovel end and the transverse pipe joint support may be located adjacent to the rearward shovel end, so that a pipe joint can be scooped from the elongated trough onto the pipe shovel such that the end of the pipe joint engages with the transverse pipe joint support.

In some embodiments, the gripping mechanism of the skate apparatus may be configured to grip a pipe joint between the gripper head and the lower pipe joint support. In some embodiments, the pipe handling apparatus may be further comprised of a rearward lifting mechanism for raising and lowering the rearward carriage end relative to the base frame.

The rearward lifting mechanism may be comprised of any structure, device or apparatus or combination of structures, devices and/or apparatus which is capable of raising and lowering the rearward carriage end relative to the base frame. The rearward lifting mechanism may be driven in any suitable manner, including as non-limiting examples, mechanically, electrically, pneumatically and/or hydraulically. In some embodiments, the rearward lifting mechanism may be comprised of a rearward jacking device, wherein the rearward jacking device may be driven in any suitable manner. As non-limiting examples, the rearward jacking device may be driven mechanically, electrically, pneumatically and/or hydraulically. In some particular embodiments, the rearward jacking device may be hydraulically driven. In some embodiments, the rearward lifting mechanism may be comprised of:

(i) a rearward lifting member having a frame attachment end and a carriage attachment end, wherein the frame attachment end is pivotably connected with the base frame and wherein the carriage attachment end is pivotably connected with the lift carriage; and

(ii) an extendible and retractable rearward jacking device having a lower jack end and an upper jack end, wherein the lower jack end is pivotably connected with the base frame and wherein the upper jack end is pivotably connected with the rearward lifting member at a location between the frame attachment end and the carriage attachment end.

The rearward lifting member may be comprised of a single rearward member or may be comprised of a plurality of rearward members. In some embodiments, the rearward lifting member may be comprised of a pair of rearward members.

The rearward jacking device may be comprised of a single jacking device or may be comprised of a plurality of jacking devices. In some embodiments, the rearward jacking device may be comprised of a pair of jacking devices.

In some embodiments, one of a pair of jacking devices may be associated with one of a pair of rearward members, and the other of the pair of jacking devices may be associated with the other of the pair of rearward members, so that the rearward lifting mechanism is comprised of a pair of identical or similar arrangements of a rearward member and a rearward jacking device.

In some embodiments, the rearward lifting mechanism may be configured so that the rearward jacking device extends in a rearward jack extending direction toward the forward frame end and retracts in a rearward jack retracting direction toward the rearward frame end.

In some embodiments, the rearward lifting mechanism may be identical or similar to the forward lifting mechanism as previously described. In some embodiments, the forward lifting mechanism may be identical or similar to the rearward lifting mechanism as previously described. In some embodiments, the forward lifting mechanism and the rearward lifting mechanism may be identical or similar to each other.

In some embodiments, the pipe handling apparatus may be comprised of a plurality of lifting assemblies for lifting the pipe handling apparatus relative to a bearing surface. The bearing surface may be any surface upon which the pipe handling apparatus may be positioned, including as non-limiting examples, a ground surface, a slab, a deck, a skid, a trailer, etc. In some embodiments, the base frame may define a base frame bearing plane for engaging with a bearing surface.

In some embodiments, a lifting assembly may be comprised of a support leg having a bearing foot at a lower end of the support leg for engaging with the bearing surface. In some embodiments, the support leg may be actuatable vertically between a fully retracted position in which the bearing foot is above the base frame bearing plane and a fully extended position in which the bearing foot is a lifting distance below the base frame bearing plane. In some embodiments, the support leg may be actuatable laterally between a fully retracted position in which the support leg is adjacent to the base frame and a fully extended position in which the support leg is a lateral clearance distance from the base frame. The support leg may be actuated vertically and actuated laterally in any suitable manner including, as non-limiting examples, mechanically, electrically, pneumatically and/or hydraulically.

In some embodiments, a lifting assembly may be comprised of a device for actuating the support leg vertically. In some embodiments, the device for actuating the support leg vertically may be comprised of a vertical jacking device, wherein the vertical jacking device may be driven in any suitable manner. As non-limiting examples, the vertical jacking device may be driven mechanically, electrically, pneumatically and/or hydraulically. In some particular embodiments, the vertical jacking device may be hydraulically driven.

In some embodiments, a lifting assembly may be comprised of a device for actuating the support leg laterally. In some embodiments, the device for actuating the support leg laterally may be comprised of a lateral jacking device, wherein the lateral jacking device may be driven in any suitable manner. As non-limiting examples, the lateral jacking device may be driven mechanically, electrically, pneumatically and/or hydraulically. In some particular embodiments, the lateral jacking device may be hydraulically driven.

In some embodiments, the base frame may have four corners. In some such embodiments, the pipe handling apparatus may be comprised of four lifting assemblies. In some such embodiments, one of the lifting assemblies may be associated with each of the four corners of the base frame. In some embodiments, the pipe handling apparatus may be comprised of one or more lifting assemblies which are associated with one or more edges of the base frame between two corners of the base frame.

In some embodiments, the pipe handling apparatus may be comprised of a ramp for moving objects from the pipe handling apparatus to an elevated location relative to the pipe handling apparatus. The ramp may be comprised of a lower ramp end and an upper ramp end. In some embodiments, the lower ramp end may be pivotably connected with the base frame. In some embodiments, the lower ramp end may be pivotably connected with the forward frame end of the base frame. The ramp may be pivoted relative to the base frame in any suitable manner, including as non-limiting examples, manually, mechanically, electrically, pneumatically and/or hydraulically. In some particular embodiments, the ramp may be pivoted relative to the base frame manually.

In some embodiments, the ramp may be extendable and retractable to vary the distance between the lower ramp end and the upper ramp end. The ramp may be extended and retracted in any suitable manner, including as non-limiting examples, manually, mechanically, electrically, pneumatically and/or hydraulically.

In some embodiments, the ramp may be comprised of a lower ramp section and an upper ramp section which is extendable and retractable relative to the lower ramp section. In some embodiments, the upper ramp section may be received within a track defined by the lower ramp section so that the upper ramp section slides in the track in order to extend and retract the upper ramp section relative to the lower ramp section.

In some embodiments, the ramp may be comprised of a device for extending and retracting the upper ramp section relative to the lower ramp section. In some embodiments, the device for extending and retracting the upper ramp section relative to the lower ramp section may be comprised of a ramp jacking device, wherein the ramp jacking device may be driven in any suitable manner. As non-limiting examples, the ramp jacking device may be driven mechanically, electrically, pneumatically and/or hydraulically. In some particular embodiments, the ramp jacking device may be hydraulically driven.

In some embodiments, the ramp may be comprised of a ramp jacking device for extending and retracting the upper ramp section relative to the lower ramp section in order to extend and retract the ramp. The ramp jacking device may be comprised of a single jacking device or may be comprised of a plurality of jacking devices.

Various features of the pipe handling apparatus may be combined in different arrangements, so that all features of the invention are not necessarily included in all embodiments of the pipe handling apparatus. Many different arrangements of features of the pipe handling apparatus are possible within the scope of the invention.

In a second exemplary apparatus aspect, the invention is a pipe handling apparatus comprising:

(a) a base frame, wherein the base frame has a forward frame end and a rearward frame end;

(b) an extendable and retractable lift carriage connected with the base frame, wherein the lift carriage is comprised of a forward carriage end, a rearward carriage end, and an elongated trough; and

(c) a forward lifting mechanism for raising and lowering the forward carriage end relative to the base frame, wherein the forward lifting mechanism is comprised of:

The second exemplary apparatus aspect may be further comprised of other features of the pipe handling apparatus.

In a third exemplary apparatus aspect, the invention is a pipe handling apparatus comprising:

(b) a lift carriage connected with the base frame, wherein the lift carriage is comprised of a forward carriage end, a rearward carriage end, and an elongated trough;

(c) a forward lifting mechanism for raising and lowering the forward carriage end relative to the base frame; and

(d) a skate apparatus which is configured to engage with a pipe joint positioned in the elongated trough in order to move the pipe joint along the elongated trough, wherein the skate apparatus is movable along the elongated trough, wherein the skate apparatus is comprised of a gripping mechanism which is configured to grip the pipe joint so that the pipe joint can be moved along the elongated trough by the skate apparatus, and wherein the gripping mechanism is comprised of a first gripper section, a second gripper section and an actuatable gripper head operably connected with the first gripper section and the second gripper section, wherein the gripper head is actuated by relative movement between the first gripper section and the second gripper section.

The third exemplary apparatus aspect may be further comprised of other features of the pipe handling apparatus.

In a fourth exemplary apparatus aspect, the invention is a pipe handling apparatus comprising: a base frame, wherein the base frame has a forward frame end, a rearward frame end, four corners, and defines a base frame bearing plane for engaging with a bearing surface; a lift carriage connected with the base frame, wherein the lift carriage is comprised of a forward carriage end, a rearward carriage end, and an elongated trough; a forward lifting mechanism for raising and lowering the forward carriage end relative to the base frame; and four lifting assemblies, wherein one of the lifting assemblies is associated with each of the four corners of the base frame, and wherein each of the lifting assemblies is comprised of a support leg having a bearing foot at a lower end of the support leg for engaging with the bearing surface, wherein the support leg is actuatable vertically between a fully retracted position in which the bearing foot is above the base frame bearing plane and a fully extended position in which the bearing foot is a lifting distance below the base frame bearing plane, and wherein the support leg is actuatable laterally between a fully retracted position in which the support leg is adjacent to the base frame and a fully extended position in which the support leg is a lateral clearance distance from the base frame.

The fourth exemplary apparatus aspect may be further comprised of other features of the pipe handling apparatus. In a fifth exemplary apparatus aspect, the invention is a pipe handling apparatus comprising: a base frame, wherein the base frame has a forward frame end and a rearward frame end; an extendable and retractable lift carriage connected with the base frame, wherein the lift carriage is comprised of a forward carriage end, a rearward carriage end, and an elongated trough; a forward lifting mechanism for raising and lowering the forward carriage end relative to the base frame; and

(d) a rearward lifting mechanism for raising and lowering the rearward carriage end relative to the base frame.

The fifth exemplary apparatus aspect may be further comprised of other features of the pipe handling apparatus. In a method aspect, the method is comprised of providing a pipe handling apparatus comprising a base frame, a lift carriage and at least one lifting mechanism for lifting the lift carriage relative to the base frame, and selectively moving components of the pipe handling apparatus relative to each other in order to deliver pipe joints to and from an elevated platform such as the floor of a drilling rig, a service rig or an offshore rig.

The selective moving of components of the pipe handling apparatus relative to each other may be comprised of raising and lowering a forward carriage end of the lift carriage, raising and lowering a rearward carriage end of the lift carriage, and/or extending and/or retracting the lift carriage to extend and retract the forward carriage end of the lift carriage relative to the base frame.

In a particular embodiment, a method of delivering a pipe joint to an elevated platform may be comprised of the following sequence in the order set forth:

(a) raising the forward carriage end of the lift carriage; (b) raising the rearward carriage end of the lift carriage, and

(c) extending the lift carriage.

In a particular embodiment, a method of delivering a pipe joint from an elevated platform may be comprised of the following sequence in the order set forth:

(a) retracting the lift carriage;

(b) lowering the rearward carriage end of the lift carriage, and

(c) lowering the forward carriage end of the lift carriage.

In some embodiments, the method may be further comprised of positioning the pipe handling apparatus adjacent to an elevated platform.

In some embodiments, the method may be further comprised of receiving a pipe joint in an elongated trough of the lift carriage. In some embodiments, the method may be further comprised of removing a pipe joint from an elongated trough of the lift carriage.

In some embodiments, the pipe handling apparatus may be comprised of a skate apparatus, and the selective moving of components of the pipe handling apparatus may be comprised of moving a pipe joint along an elongated trough of the lift carriage with the skate apparatus.

In some embodiments, the method may be performed using a pipe handling apparatus according to the apparatus of the invention. In such embodiments, the method may be comprised of operating the pipe handling apparatus of the invention to utilize various features of the apparatus of the invention.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a pictorial view of a first exemplary embodiment of a pipe handling apparatus according to the invention. Figure 2 is a pictorial view of a second exemplary embodiment of a pipe handling apparatus according to the invention.

Figure 3 is an isolated pictorial view of the base frame of the second exemplary embodiment of pipe handling apparatus depicted in Figure 2.

Figure 4 is an isolated pictorial view of the lift carriage, the forward lifting mechanism and the rearward lifting mechanism of the second exemplary embodiment of pipe handling apparatus depicted in Figure 2. Figure 5 is a pictorial view of an exemplary embodiment of a skate apparatus according to the invention, depicting the gripping mechanism actuated to a pipe release position.

Figure 6 is a side view of the exemplary embodiment of skate apparatus shown in Figure 5, depicting the gripping mechanism actuated to a pipe release position.

Figure 7 is a plan view of the exemplary embodiment of skate apparatus shown in Figure 5, depicting the gripping mechanism actuated to a pipe release position. Figure 8 is a pictorial view of the exemplary embodiment of skate apparatus shown in Figure 5, depicting the gripping mechanism actuated to a pipe gripping position.

Figure 9 is a side view of the exemplary embodiment of skate apparatus shown in Figure 5, depicting the gripping mechanism actuated to a pipe gripping position.

Figure 10 is a top view of the exemplary embodiment of skate apparatus shown in Figure 5, depicting the gripping mechanism actuated to a pipe gripping position.

Figure 1 1 is a pictorial view of an exemplary embodiment of a lifting assembly according to the invention. Figure 12 is an end view of an embodiment of a pipe handling apparatus according to the invention, depicting the exemplary embodiment of lifting assembly shown in Figure 1 1 associated with two corners of the base frame.

Figure 13 is a pictorial view of a pipe handling apparatus according to the invention, depicting the exemplary embodiment of lifting assembly shown in Figure 1 1 associated with four corners of the base frame, with the lifting assemblies actuated vertically to the fully retracted position and actuated laterally to the fully retracted position.

Figure 14 is a pictorial view of a pipe handling apparatus according to the invention, depicting the exemplary embodiment of lifting assembly shown in Figure 1 1 associated with four corners of the base frame, with the lifting assemblies actuated vertically to the fully extended position and actuated laterally to the fully extended position.

Figure 15 is a top view of an exemplary embodiment of a ramp according to the invention, depicting the upper ramp actuated to a retracted position.

Figure 16 is a side view of the exemplary embodiment of ramp shown in Figure 15, depicting the ramp actuated to a retracted position.

Figure 17 is a plan view of the exemplary embodiment of ramp shown in Figure 15, depicting the ramp actuated to a retracted position. Figure 18 is a top view of the exemplary embodiment of ramp shown in Figure

15, depicting the upper ramp actuated to an extended position.

Figure 19 is a side view of the exemplary embodiment of ramp shown in Figure 15, depicting the ramp actuated to an extended position.

Figure 20 is a plan view of the exemplary embodiment of ramp shown in Figure 15, depicting the ramp actuated to an extended position. DETAILED DESCRIPTION

Exemplary embodiments of pipe handling apparatus (20) according to the invention are depicted in Figures 1-20. The pipe handling apparatus (20) may be used to move objects such as pipe joints to and from an elevated platform (not shown) such as the floor of a drilling rig, a service rig or an offshore rig.

Figure 1 depicts a first exemplary embodiment of the pipe handling apparatus (20). Figures 2-4 depict a second exemplary embodiment of the pipe handling apparatus (20). Figures 5-20 depict exemplary embodiments of features of the pipe handling apparatus (20) which may be incorporated into various embodiments of the pipe handling apparatus (20), including the first exemplary embodiment and the second exemplary embodiment.

In the description that follows, equivalent features in the first exemplary embodiment and the second exemplary embodiment are assigned common reference characters.

Referring to Figure 1, the first exemplary embodiment of pipe handling apparatus (20) is comprised of a base frame (22), a lift carriage (24), and a forward lifting mechanism (26) as major components. The first exemplary embodiment of pipe handling apparatus (20) is particularly suited for use in association with a service rig (not shown), but may also be used in association with a drilling rig (not shown) or an offshore rig (not shown).

Referring to Figures 2-4, the second exemplary embodiment of pipe handling apparatus (20) is comprised of a base frame (22), a lift carriage (24), a forward lifting mechanism (26) and a rearward lifting mechanism (28) as major components. By including the rearward lifting mechanism (28), the second exemplary embodiment is capable of an additional movement which is not provided by the first exemplary embodiment. The second exemplary embodiment of pipe handling apparatus (20) is particularly suited for use in association with a drilling rig (not shown), but may also be used in association with a service rig (not shown) or an offshore rig (not shown).

In the exemplary embodiments, the base frame (22) is the principal structural component of the pipe handling apparatus (20), and supports and/or stores other components of the pipe handling apparatus (20). As non-limiting examples, the base frame (22) may include one or more toolboxes (not shown) and/or stow locations (not shown) and/or may provide routing and storage for electrical cables and hydraulic lines. In the exemplary embodiments, as best seen in Figure 3, the structural elements of the base frame (22) may be constructed of structural steel components, such as hollow structural section (HSS) and wide flange (WF) components.

Referring to Figures 1 -2, in the exemplary embodiments, the base frame (22) is generally rectangular in shape, has four corners, a forward frame end (40), a rearward frame end (42), and defines a base frame bearing plane (44) for engaging with a bearing surface (not shown) such as a ground surface, a slab, a deck, a skid, a trailer, etc.

In the exemplary embodiments, the base frame (22) provides a mount for a central hydraulic power unit (50) which provides hydraulic power for actuating various hydraulic components of the pipe handling apparatus (20). In the exemplary embodiments, the hydraulic power unit (50) is comprised of typical hydraulic power components such as a motor, a hydraulic fluid reservoir, filters, a valve bank, etc.

In other embodiments, power for actuating one or more components of the pipe handling apparatus (20) may be provided to the pipe handling apparatus (20) from one or more sources which are separate from the pipe handling apparatus (20). As non-limiting examples, electrical, mechanical and/or hydraulic power may be provided to the pipe handling apparatus (20) from a drilling rig, a service rig, and/or from an independent power source such as a generator.

In other embodiments, one or more components of the pipe handing apparatus (20) may be provided with dedicated power sources for actuating the components, and/or one or more components may share a dedicated power source.

In the exemplary embodiments, the base frame (22) is provided with leveling jacks (52) at each of the four corners. The leveling jacks (52) assist in leveling the pipe handling apparatus (20) in circumstances in which the bearing surface is not level. In the exemplary embodiments, the leveling jacks (52) are hydraulically actuated. The leveling jacks (52) may be controlled by the hydraulic power unit (50) and/or may be controlled manually to provide leveling functionality in circumstances when the hydraulic power unit (50) is not operable. Referring to Figure 1 , the base frame (22) is configured to receive the lift carriage (24) and the forward lifting mechanism (26) within the base frame (22) for transport or storage of the pipe handling apparatus (20). Referring to Figure 2, the base frame (22) is configured to receive the lift carriage (24), the forward lifting mechanism (26) and the rearward lifting mechanism (28) for transport or storage of the pipe handling apparatus (20).

Referring to Figures 1-2 and Figure 4, in the exemplary embodiments, the lift carriage (24) has a forward carriage end (60) and a rearward carriage end (62). In the exemplary embodiments, the lift carriage (24) is comprised of a first carriage stage (64) and a second carriage stage (66).

The first carriage stage (64) is the principal structural element of the lift carriage (24). The forward carriage end (60) and the rearward carriage end (62) are defined by the first carriage stage (64).

The second carriage stage (66) is comprised of an elongated trough (68) for receiving a pipe joint. In the exemplary embodiments, the elongated trough (68) is a generally V-shaped trough which extends for substantially the entire length of the second carriage stage (66) and which is configured to accommodate the sizes and lengths of pipe joints which are to be handled by the pipe handling apparatus (20).

The second carriage stage (66) is extendable relative to the first carriage stage (64) in a carriage extending direction and the second carriage stage (66) is retractable relative to the first carriage stage (64) in a carriage retracting direction. The second carriage stage (66) is received within a track (70) defined by the first carriage stage (64) so that the second carriage stage (66) slides within the track (70) in order to extend and retract the second carriage stage (66) relative to the first carriage stage (64). In the exemplary embodiments, the track (70) is provided with cam followers (72) to minimize the friction between the track (70) and the second carriage stage (66).

The second carriage stage (66) contains a hose carrier (74) which extends within the second carriage stage (66). The hose carrier (74) carries and organizes hydraulic hoses which are required for the actuation of elements of the lift carriage (24). In the exemplary embodiments, the lift carriage (24) is comprised of a carriage chain drive (76) which is interposed between the first carriage stage (64) and the second carriage stage (66), and the second carriage stage (66) is extended and retracted relative to the first carriage stage (64) with the carriage chain drive (76). In the exemplary embodiments, the carriage chain drive (76) is driven by a hydraulic motor (not shown) which is powered by the hydraulic power unit (50).

In other embodiments, the second carriage stage (66) may be extended and retracted relative to the first carriage stage (64) in some other manner, including as a non- limiting example, with a carriage jacking device such as a hydraulically powered jacking device (not shown) or a screw jack (not shown.

In the exemplary embodiments, the pipe handling apparatus (20) is comprised of two sets of three kickers (80) spaced along the length of the elongated trough (68), for removing a pipe joint from the elongated trough (68). One set of three kickers (80) is configured to direct a pipe joint to one side of the lift carriage (24), and the other set of three kickers (80) is configured to direct a pipe joint to the other side of the lift carriage (24).

In the exemplary embodiments, the kickers (80) are generally V-shaped to match the elongated trough (68) and are positioned in gaps in the elongated trough (68). The kickers (80) are pivotable between a home position in which the kickers (80) lie flush with the elongated trough (68) and a kicking position in which the kickers (80) pivot toward a side of the lift carriage (24) to lift a pipe joint from the elongated trough (68) and direct the pipe joint toward the side of the lift carriage (24). In the exemplary embodiments, each set of three kickers (80) is actuatable independently, and all three kickers (80) in a set of kickers (80) are actuated together.

The kickers (80) may be powered in any suitable manner, including as non- limiting examples, mechanically, electrically, pneumatically and/or hydraulically. In the exemplary embodiments, the kickers (80) are actuated hydraulically and are powered by the hydraulic power unit (50).

In the exemplary embodiments, a safety feature for the kickers (80) is provided, in which the home position of the kickers (80) is the default position of the kickers (80). In the exemplary embodiments, the kickers (80) automatically return to the home position after actuation of the kickers (80) to the kicking position, and automatically return to the home position whenever the lift carriage (24) is raised relative to the base frame (22).

In the exemplary embodiments, a further safety feature for the kickers (80) is that the kickers (80) are configured so that they cannot be actuated if the lift carriage (24) is not in its home position (in which the forward carriage end (60) and the rearward carriage end (62) are both lowered relative to the base frame (22)).

Referring to Figures 1 -2 and Figure 4, in the exemplary embodiments the forward lifting mechanism (26) is comprised of a lower lifting member comprising a pair of lower members (90), an upper lifting member comprising a pair of upper members (92), and a pair of forward jacking devices (94). In the exemplary embodiments, the forward jacking devices (94) are hydraulically powered by the hydraulic power unit (50). The lower members (90) each have a frame attachment end (96) and a frame remote end (98). The upper members (92) each have a carriage attachment end (100) and a carriage remote end (102). The frame attachment ends (96) of the lower members (90) are pivotably connected with the base frame (22) adjacent to the forward frame end (40). The carriage attachment ends (100) of the upper members (92) are pivotably connected with the first carriage stage (64) of the lift carriage (24) adjacent to the forward carriage end (60). The frame remote ends (98) of the lower members (90) are pivotably connected with the carriage remote ends (102) of the corresponding upper members (92).

The forward jacking devices (94) each have a lower jack end (1 10) and an upper jack end (1 12). The lower jack ends (1 10) of the forward jacking devices (94) are pivotably connected with corresponding lower members (90) at a location between the frame attachment ends (96) and the frame remote ends (98). The upper jack ends (1 12) of the forward jacking devices (94) are pivotably connected with corresponding upper members (92) at a location between the carriage attachment ends (100) and the carriage remote ends (102).

In the exemplary embodiments, the forward lifting mechanism (26) is configured so that the frame remote ends (98) of the lower members (90) and the carriage remote ends (102) of the upper members (92) are located between the forward jacking devices

(94) and the rearward frame end (42). Stated otherwise, in the exemplary embodiments, the forward lifting mechanism (26) is configured so that the vertexes (1 14) formed between the lower members (90) and the upper members (92) are directed toward the rearward frame end (42). This configuration enables the lower members (90), the upper members (92) and the forward jacking devices (94) to rest within the base frame (22) when the forward carriage end (60) is lowered relative to the base frame (22).

Referring to Figure 1 , in the first exemplary embodiment, the first carriage stage (64) is pivotably connected with the base frame (22) adjacent to the rearward frame end (42) such that the rearward carriage end (62) is pivotably connected with the base frame (22). In the first exemplary embodiment, the rearward carriage end (62) is not capable of raising and lowering relative to the base frame (22).

Referring to Figures 2-4, in the second exemplary embodiment, the pipe handling apparatus (20) is comprised of a rearward lifting mechanism (28) so that the rearward carriage end (62) is connected with the base frame (22) by the rearward lifting mechanism (28). In the second exemplary embodiment, the rearward carriage end (62) is raised and lowered relative to the base frame (22) by the rearward lifting mechanism (28).

In the second exemplary embodiment, the rearward lifting mechanism (28) is comprised of a rearward lifting member comprising a pair of rearward members (120) and a pair of rearward jacking devices (122). In the second exemplary embodiment, the rearward jacking devices (122) are hydraulically powered by the hydraulic power unit (50).

The rearward members (120) each have a frame attachment end (124) and a carriage attachment end (126). The frame attachment ends (124) of the rearward members (120) are pivotably connected with the base frame (22) at a distance from the rearward frame end (42) which is somewhat greater than the length of the rearward members (120) so that the rearward members (120) rest within the base frame (22) when the rearward carriage end (62) is lowered relative to the base frame (22). The carriage attachment ends (126) of the rearward members (120) are pivotably connected with the first carriage stage (64) of the lift carriage (24) adjacent to the rearward carriage end (62).

The rearward jacking devices (122) each have a lower jack end (130) and an upper jack end (132). The lower jack ends (130) of the rearward jacking devices (122) are pivotably connected with the base frame (22). The upper jack ends (132) of the rearward jacking devices (122) are pivotably connected with corresponding rearward members (120) at a location between the frame attachment ends (124) and the carriage attachment ends (126).

In the exemplary embodiments, the rearward lifting mechanism (28) is configured so that the rearward jacking devices (122) extend in a rearward jack extending direction toward the forward frame end (40) and retract in a rearward jack retracting direction toward the rearward frame end (42). This configuration enables the rearward members (120) and the rearward jacking devices (122) to rest within the base frame (22) when the rearward carriage end (62) is lowered relative to the base frame (22).

Referring to Figures 1-2, in the exemplary embodiments, the pipe handling apparatus (20) is comprised of a pair of integrated gullwing pipe racks (140) which are connected with the base frame (22) on one side of the base frame (22). The gullwing pipe racks (140) may be pivoted horizontally against the base frame (22) for storage and may be pivoted horizontally away from the base frame (22) for use. The purpose of the gullwing pipe racks (140) is to provide a pipe rack in circumstances in which a pipe rack is not otherwise available on-site and/or to provide a backup pipe rack in other circumstances.

Each of the gullwing pipe racks (140) is comprised of a substantially horizontal pipe rest arm (142), a substantially vertical dropleg (144) extending downward from the end of the pipe rest arm (142), and a hydraulically powered gullwing jacking device (146) for extending and retracting the dropleg (142). An adjustable or interchangeable pipe end stop pin (148) extends upward from the end of the pipe rest arm (142) to prevent pipe from rolling off the end of the pipe rest arm (142). When in use, the droplegs (142) may be extended downward to engage a bearing surface to provide a desired slope of the gullwing pipe racks (140) relative to the base frame (22), thereby enabling pipe joints to be fed to the lift carriage (24) or collected from the pipe carriage (24).

Each of the gullwing pipe racks (140) is also comprised of an indexer (150) which is pivotably received within the pipe rest arm (142) and which is pivotable vertically relative to the pipe rest arm (142). Each of the gullwing pipe racks (140) is also comprised of a pipe stop pin (not shown) which protrudes from the pipe rest arm (142) between the indexer

(150) and the lift carriage (24) and which retains pipe joints behind the indexer (150) as the indexer (150) pivots with a pipe joint over the pipe stop pin, thereby ensuring that only one pipe joint at a time is in motion between the gullwing pipe racks (140) and the lift carriage (24). In the exemplary embodiments, the gullwing pipe racks (140) are pivoted horizontally relative to the frame manually, the gullwing jacking devices (144) are powered by the hydraulic power unit (50) to extend and retract the gullwing jack droplegs (142), and the indexers (150) are hydraulically powered by the hydraulic power unit (50) to pivot the indexers (150) relative to the pipe rest arms (142).

Referring to Figures 1 -2, in the exemplary embodiments, the pipe handling apparatus (20) is comprised of a pair of pipe rack indexers (160) which are connected with the base frame (22) on the opposite side of the base frame (22) from the gullwing pipe racks (140). The pipe rack indexers (160) may be pivoted horizontally against the base frame (22) for storage and may be pivoted horizontally away from the base frame (22) for use.

The purpose of the pipe rack indexers (160) is to provide an indexer for use in association with pipe racks (not shown) which may be present on-site. Each of the pipe rack indexers (160) may be pivoted vertically relative to the base frame (142) to feed a pipe joint to the lift carriage (24) or to collect a pipe joint from the lift carriage (24), thereby ensuring that only one pipe joint at a time is in motion between the on-site pipe racks and the lift carriage (24).

In the exemplary embodiments, the pipe rack indexers (160) are pivoted horizontally relative to the frame manually and are powered by the hydraulic power unit (50) to pivot the pipe rack indexers (160) vertically relative to the base frame (22). Referring to Figures 1 , 2, and 4-10, in some embodiments, the pipe handling apparatus (20) may be comprised of a skate apparatus (168) which is movable along substantially the entire length of the elongated trough (68). The purpose of the skate apparatus (168) is to move a pipe joint along the elongated trough (68). The skate apparatus (168) is capable of moving a pipe joint along the elongated trough (68) in both directions.

An exemplary embodiment of a skate apparatus (168) according to the invention is depicted in Figures 1 , 2 and 4-10.

Referring to Figures 5-10, in the exemplary embodiment, the skate apparatus (1 8) is comprised of a gripping mechanism (170) which is configured to grip a pipe joint so that the pipe joint can be moved along the elongated trough (68) while being gripped by the gripping mechanism (170).

In the exemplary embodiment, the gripping mechanism (170) is comprised of a first gripper section (172), a second gripper section (174) and an actuatable gripper head (176) which is operably connected with the first gripper section (172) and the second gripper section (174) by a mechanical gripper linkage (178).

In the exemplary embodiment, the gripper head (176) is comprised of a plurality of connected members which are adjustable relative to each other in order to vary the gripping characteristics of the gripper head (176).

In the exemplary embodiment, a first end of the gripper head (176) is pivotably connected with a gripper head mount (180) on the second gripper section (174) so that the gripper head (176) is directly connected with the second gripper section (174). In the exemplary embodiment, a second end of the gripper head (176) is comprised of a pivotable gripper pad (182) for engaging with a pipe joint.

In the exemplary embodiment, the mechanical gripper linkage (178) is comprised of a linkage member (184) which is pivotably connected at one end with the first gripper section (172) and at the other end with a lug (186) on the gripper head (176) which is located between the ends of the gripper head (176), so that the gripper head (176) pivots about the gripper head mount (180) in response to movement of the linkage member. In the exemplary embodiment, the gripper head (176) is actuatable between a pipe gripping position and a pipe release position by relative movement between the first gripper section (172) and the second gripper section (174). In Figures 5-7, the gripper head (176) is depicted actuated to the pipe release position. In Figures 8-10, the gripper head (176) is depicted actuated to the pipe gripping position.

In the exemplary embodiment, the first gripper section (172) and the second gripper section (174) are both reciprocably connected with the elongated trough (68) so that they can move along the elongated trough (68). In the exemplary embodiment, the first gripper section (172) is moved along the elongated trough (68) by a skate chain drive (188) which extends along both sides of the first gripper section (172) and which is driven by a hydraulic motor (not shown). The hydraulic motor is powered by the hydraulic power unit (50).

In the exemplary embodiment, the second gripper section (174) is moved along the elongated trough (68) by the first gripper section (172). In other words, the second gripper section (174) is not directly connected with the skate chain drive (188) or with any other drive mechanism.

The first gripper section (172) is reciprocably connected with the second gripper section (174) by a reciprocating linkage (190) such that the first gripper section (172) and the second gripper section (174) are capable of reciprocating relative to each other along the elongated trough (68) by an actuating amount of relative reciprocating movement.

In the exemplary embodiment, the reciprocating linkage (190) is comprised of a pair of outer guide tubes (192) associated with the first gripper section (172) and a pair of inner guide tubes (194) associated with the second gripper section (174), wherein the inner guide tubes (194) are slidingly received within the outer guide tubes (192) to provide the relative reciprocating movement between the first gripper section (172) and the second gripper section (174). The use of pairs of guide tubes (172, 174) helps to maintain alignment of the first gripper section (172) and the second gripper section (174) as they reciprocate relative to each other, thereby minimizing binding or locking between the first gripper section (172) and the second gripper section (174).

Stops (1 6) are provided on the ends of the inner guide tubes (194) to limit the relative reciprocating movement of the first gripper section (172) and the second gripper section (174) away from each other. When the stops (196) on the inner guide tubes (1 4) are engaged with the outer guide tubes (192), the gripper head (176) is actuated to the pipe gripping position.

Surfaces (198) are provided on the first gripper section (172) and the second gripper section (174) to limit the relative reciprocating movement of the first gripper section (172) and the second gripper section (174) toward each other. When the surfaces (198) on the first gripper section (172) and the second gripper section (174) are engaged with each other, the gripper head (176) is actuated to the pipe release position.

The actuating amount of relative reciprocating movement is equal to the amount of relative reciprocating movement which is possible between the first gripper section ( 172) and the second gripper section (174), and is defined by the length of the guide tubes (172, 174) and by the distance between the stops (196) and the surfaces (198).

Once the limit of relative reciprocating movement between the first gripper section (172) and the second gripper section (174) is reached as a result of engagement between the stops (196) and the outer guide tubes (192) or as a result of engagement between the surfaces (198), the second gripper section (174) is moved along the elongated trough (68) by the first gripper section (172). In the exemplary embodiment, each of the first gripper section (172) and the second gripper section (174) has a reciprocating resistance relative to the elongated trough (68). In the exemplary embodiments, the reciprocating resistance of the second gripper section (174) is greater than the reciprocating resistance of the first gripper section (172). In the exemplary embodiments, the second gripper section (174) is comprised of wear pads (200) which are clamped to the elongated trough (68) in order to provide the reciprocating resistance of the second gripper section (174). The clamping force (and thus the reciprocating resistance of the second gripper section (174)) is adjustable by tightening or loosening wear pad bolts (202) which connect the wear pads with the second gripper section (174). In the exemplary embodiment, the skate apparatus (168) is comprised of a lower pipe joint support (210) for supporting a pipe joint on the skate apparatus (168). In the exemplary embodiment, the lower pipe joint support (210) is generally V-shaped in order to be compatible with the shape of the elongated trough (68). In the exemplary embodiment, the gripping mechanism (170) is configured to grip a pipe joint between the gripper head (176) and the lower pipe joint support (210).

In the exemplary embodiment, the lower pipe joint support (210) is comprised of a pipe shovel for scooping an end of a pipe joint from the elongated trough (68) into engagement with the skate apparatus (168). The pipe shovel has a forward shovel end (212) and a rearward shovel end (214). The forward shovel end (212) is comprised of a tapered surface (216) for assisting in scooping the end of the pipe joint.

In the exemplary embodiment, the skate apparatus (168) is comprised of a transverse pipe joint support (218) for engaging with the end of a pipe joint so that the skate apparatus (168) can push the pipe joint along the elongated trough (170). In the exemplary embodiments, the transverse pipe joint support (218) is located adjacent to the rearward shovel end (214). In the exemplary embodiment, the transverse pipe joint support (218) may be comprised of a wear pad to minimize damage to the ends of pipe joints which engage the transverse pipe joint support (218).

In the exemplary embodiment, the lower pipe joint support (210) and the transverse pipe joint support (218) are associated with the second gripper section (174). In the exemplary embodiment, the skate apparatus (168) is configured so that the gripper head (176) is actuated to the pipe gripping position by moving the first gripper section (172) toward the rearward carriage end (62) relative to the elongated trough (68), and so that the gripper head (176) is actuated to the pipe release position by moving the first gripper section (172) toward the forward carriage end (60) relative to the elongated trough (68).

As a result, the skate apparatus (168) may be used to push a pipe joint up the elongated trough (68) toward the forward carriage end (60) by engaging the end of the pipe joint with the transverse pipe joint support (218), and may be used to pull a pipe joint down the elongated trough (68) toward the rearward carriage end (62) by gripping the pipe joint between the gripper head (184) and the lower pipe joint support (210).

In order to push a pipe joint up the elongated trough (68) with the skate apparatus (168): 1. the first gripper section (172) is advanced toward the forward carriage end (60) and toward the pipe joint by the skate chain drive (188) until the surfaces (198) on the first gripper section (172) and the second gripper section (174) become engaged. In this position, the gripper head (176) is actuated to the pipe release position; 2. the first gripper section (172) is then advanced further toward the forward carriage end (60) by the skate chain drive (188). The second gripper section (174) will advance toward the forward carriage end (60) with the first gripper section (172), causing the end of the pipe joint to be scooped from the elongated trough (68) by the lower pipe joint support (210) and to become engaged with the transverse pipe joint support (218); and

3. the first gripper section (172) is then advanced further toward the forward carriage end (60) by the skate chain drive (188). The second gripper section (174) will advance toward the forward carriage end (60) with the first gripper section (172), and the pipe joint will be pushed up the elongated trough (68) by the skate apparatus (168) as the skate apparatus (168) continues to advance toward the forward carriage end (60). In order to pull a pipe joint down the elongated trough (68) with the skate apparatus (168):

1. the first gripper section (172) is advanced toward the forward carriage end (60) and toward the pipe joint by the skate chain drive (188) until the surfaces (198) on the first gripper section (172) and the second gripper section (174) become engaged. In this position, the gripper head (176) is actuated to the pipe release position;

2. the first gripper section (172) is then advanced further toward the forward carriage end (60) by the skate chain drive (188). The second gripper section

(174) will advance toward the forward carriage end (60) with the first gripper section (172), causing the end of the pipe joint to be scooped from the elongated trough (68) by the lower pipe joint support (210) and to become engaged with the transverse pipe joint support (218);

3. the first gripper section (172) is then retracted toward the rearward carriage end

(62) by the skate chain drive (188) until the outer guide tubes (1 2) become engaged with the stops (196) on the inner guide tubes (1 4). In this position, the gripper head (176) is actuated to the pipe gripping position and the pipe joint is gripped between the gripper head (176) and the lower pipe joint support (210); 4. the first gripper section (172) is then retracted further toward the rearward carriage end (62) by the skate chain drive (188). The second gripper section (174) will retract toward the rearward carriage end (62) with the first gripper section (172), causing the pipe joint to be pulled down the elongated trough (68); and

5. once the pipe joint has been pulled down the elongated trough (68) to a desired position, the first gripper section (172) is advanced toward the forward carriage end (60) until the surfaces (198) on the first gripper section (172) and the second gripper section (174) become engaged. In this position, the gripper head (176) is actuated to the pipe release position and the pipe joint can be removed from the elongated trough (68).

Referring to Figure 1 and Figures 1 1-14, in some embodiments, the pipe handling apparatus (20) may be comprised of four lifting assemblies (226) associated with the four corners of the base frame (22). The lifting assemblies (226) may be connected with the base frame (22) or may be integrated into the base frame (22). The lifting assemblies (230) enable the pipe handling apparatus (20) to be raised and lowered relative to a bearing surface and to be unloaded from or loaded onto a trailer (not shown) for transport, without the use a crane or a picker.

An exemplary embodiment of a lifting assembly (226) according to the invention is depicted in Figure 1 and in Figures 1 1-14.

Referring to Figures 1 1-14, in the exemplary embodiment, each lifting assembly (226) is comprised of a support leg carrier (228), a support leg carrier housing (230) and a support leg (232) having a bearing foot (234) at its lower end for engaging with a bearing surface.

The support leg carrier (228) defines a vertical bore for telescopically receiving the support leg (232), and the support leg carrier housing (230) defines a lateral bore for telescopically receiving the support leg carrier (228). Each support leg (232) is actuatable vertically between a fully retracted position in which the bearing foot (234) is above the base frame bearing plane (44) so that the pipe handling apparatus (20) is supported by the base frame (22), and a fully extended position in which the bearing foot (234) is a lifting distance (236) below the base frame bearing plane (44) so that the pipe handling apparatus (20) is supported by the lifting assemblies (230). In the exemplary embodiment, the support leg (232) travels within the vertical bore of the support leg carrier (228) in order to be actuated between the fully retracted position and the fully extended position. Each support leg (232) is also actuatable laterally between a fully retracted position in which the support leg (232) is adjacent to the base frame (22) so that the width of the pipe handling apparatus (20) is minimized, and a fully extended position in which the support leg (232) is a lateral clearance distance (238) from the base frame (22) so that a trailer can be backed under the pipe handling apparatus (20) without interference from the support legs (232). In the exemplary embodiment, the support leg carrier (228) travels within the lateral bore of the support leg carrier housing (230) in order to actuate the support leg (232) between the fully retracted position and the fully extended position.

In the exemplary embodiment, each of the lifting assemblies (230) is further comprised of a device for actuating the support leg (232) vertically and a device for actuating the support leg (232) laterally.

Referring to Figure 1 1 , in the exemplary embodiment, the device for actuating the support leg (232) vertically is comprised of a hydraulically powered vertical jacking device (240) which is powered by the hydraulic power unit (50). In the exemplary embodiment, the vertical jacking device (240) is connected between the support leg carrier (228) and the support leg (232).

Referring to Figure 1 1 , in the exemplary embodiment, the device for actuating the support leg (232) laterally is comprised of a hydraulically powered lateral jacking device (242) which is powered by the hydraulic power unit (50). In the exemplary embodiment, the lateral jacking device (242) is connected between the support leg carrier (228) and the support leg carrier housing (230). Figure 13 depicts an embodiment of a pipe handling apparatus (20) according to the invention comprising the exemplary embodiment of lifting assembly (226), wherein each of the four support legs (232) is actuated to the fully retracted position both vertically and laterally, so that the pipe handling apparatus (20) is prepared to be used or transported. Figure 14 depicts an embodiment of a pipe handling apparatus (20) according to the invention comprising the exemplary embodiment of lifting assembly (226), wherein each of the four support legs (232) is actuated to the fully extended position both vertically and laterally, so that the pipe handling apparatus (20) is prepared to be unloaded from or loaded onto a trailer. To move the pipe handling apparatus (20) from the depiction of Figure 13 to the depiction of Figure 14, the support legs (232) are first actuated laterally to the fully extended position and then the support legs (232) are actuated vertically to the fully extended position. To move the pipe handling apparatus (20) from the depiction of Figure 14 to the depiction of Figure 13, the support legs (232) are first actuated vertically to the fully retracted position and then the support legs (232) are actuated laterally to the fully retracted position.

Referring to Figure 2 and Figures 15-20, in some embodiments, the pipe handling apparatus (20) may be comprised of a ramp (250) which is connected with the forward frame end (40) of the base frame (22). The ramp (250) may be pivotably connected to the forward frame end (40) of the base frame (22). The ramp (250) provides an additional or alternate option for moving objects to and from an elevated platform.

An exemplary embodiment of a ramp (250) according to the invention is depicted in Figure 2 and in Figures 15-20.

The ramp (250) has a lower ramp end (252) and an upper ramp end (254). In the exemplary embodiment, the ramp (250) is associated with the forward frame end (40) of the base frame (22). More particularly, in the exemplary embodiment, the ramp (250) is pivotably connected with the forward frame end (40) of the base frame (22) so that the ramp (250) can be pivoted against the base frame (22) for transport or storage and so that the upper ramp end (254) can be pivoted against an elevated platform for use of the ramp (250).

The ramp (250) may be pivoted relative to the base frame (22) in any suitable manner, including as non-limiting examples, mechanically, electrically, pneumatically and/or hydraulically. In the exemplary embodiment, the ramp (250) may be pivoted relative to the base frame (22) in any suitable manner, including as non-limiting examples, manually, mechanically, electrically, pneumatically and/or hydraulically. In some embodiments, the ramp (250) may be comprised of a ramp jacking device (not shown) which in some embodiments may be hydraulically powered by the hydraulic power unit (50).

The ramp (250) is extendable and retractable to vary the distance between the lower ramp end (252) and the upper ramp end (254), so that the ramp (250) may be used with elevated platforms of varying heights relative to the pipe handling apparatus (20). The ramp (250) may be extended and retracted in any suitable manner, including as non-limiting examples, mechanically, electrically, pneumatically and/or hydraulically.

In the exemplary embodiment, the ramp (250) is comprised of a lower ramp section (256) and an upper ramp section (258) which are extendable and retractable relative to each other. In the exemplary embodiments, the upper ramp section (258) is received within a track (259) defined by the lower ramp section (256) so that the upper ramp section (258) slides within the track (259) in order to extend and retract the upper ramp section (258) relative to the lower ramp section (256).

In the exemplary embodiment, the ramp (250) is comprised of a hydraulically powered ramp jacking device (260) which is connected between the lower ramp section (256) and the upper ramp section (258). The ramp jacking device (260) extends and retracts the upper ramp section (258) relative to the lower ramp section in order to extend and retract the ramp (250). In the exemplary embodiment, the ramp jacking device (260) is powered by the hydraulic power unit (50).

In the exemplary embodiment, the ramp (250) is comprised of a ramp hanger (262) at the upper ramp end (254) which provides a stable engagement between the upper ramp end (254) and an elevated platform during use of the ramp (250). In order to prepare the ramp (250) for use, the forward frame end (40) of the base frame (22) is positioned adjacent to an elevated platform, the ramp (250) is extended to the length required to engage the ramp hanger (262) with the elevated platform, and the ramp

(250) is pivoted away from the base frame (22) to engage the ramp hanger (262) with the elevated platform. Objects may then be moved up and down the ramp (250) between the bearing surface and the elevated platform with winches or in any other suitable manner. In order to prepare the ramp (250) for storage or transport, the ramp (250) is retracted fully and then pivoted toward the base frame (22) so that the ramp (250) can be supported by and/or stored on the base frame (22).

The pipe handling apparatus (20) of the invention may be comprised of additional and/or optional features.

In the exemplary embodiments of the pipe handling apparatus (20), the pipe handling apparatus (20) may be comprised a light source such as an LED light (270) for operating the pipe handling apparatus (20) at night or in circumstances of poor natural lighting. In the exemplary embodiments, the LED light (270) may be folded down for transport or storage of the pipe handling apparatus (20). In the exemplary embodiments of the pipe handling apparatus (20), the pipe handling apparatus (20) may be comprised of a visual indicator such as a strobe light (not shown) which operates whenever the pipe handling apparatus (20) is operating. The strobe light may be configured to be folded down for transport or storage of the pipe handling apparatus (20).

In the exemplary embodiments of the pipe handling apparatus (20), the pipe handling apparatus (20) may be comprised of an automated and/or centralized control system (not shown) for controlling the operation of the pipe handling apparatus (20), including, as non- limiting examples, a general purpose computer, a programmable logic controller (PLC) and/or a programmable logic valve controller (PLVC).

As a result, the pipe handling apparatus (20) may be comprised of a control panel (not shown) for receiving inputs to the control system and producing outputs from the control system, and the pipe handling apparatus (20) may be comprised of sensors for producing data for the control system with respect to the operation of the pipe handling apparatus (20).

In the exemplary embodiments of the pipe handling apparatus (20), the pipe handling apparatus (20) may be comprised of one or more emergency shutdown (ESD) switches (not shown) for immediately shutting down the operation of the pipe handling apparatus (20).

In the exemplary embodiments of the pipe handling apparatus (20), the pipe handling apparatus (20) may be comprised of a wired or wireless remote control system (not shown) for controlling the operation of the pipe handling apparatus (20) remotely.

In the exemplary embodiments of the pipe handling apparatus (20), the pipe handling apparatus (20) may be comprised of a perimeter safety system (not shown) such as a perimeter laser system which can define an area in the vicinity of the pipe handling apparatus (20) which will result in immediate shutting down of the operation of the pipe handling apparatus (20) if breached by objects or persons.

The pipe handling apparatus (20) of the invention provides great versatility as a result of the following movements of the pipe handling apparatus (20) which can be implemented and controlled in order to move pipe joints between the pipe handling apparatus (20) and an elevated platform:

1. raising and lowering the forward carriage end (60) of the lift carriage (24);

2. raising and lowering the rearward carriage end (62) of the lift carriage (24);

3. extending and retracting the lift carriage (24); and

4. advancing and retracting the skate apparatus (168) along the elongated trough (68). These movements can be combined and implemented as methods for pipe handling.

The combination of movements which is possible with the invention enables the pipe handling apparatus (20) to be used in conjunction with a wide range of different heights of elevated platform and a wide range of different lengths of pipe joint. The possible combination of movements enables a pipe joint to be presented to an elevated platform at an appropriate height and at an appropriate presentation angle.

In this document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article "a" does not exclude the possibility that more than one of the elements is present, unless the context clearly requires that there be one and only one of the elements.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

A pipe handling apparatus comprising: a base frame, wherein the base frame has a forward frame end and a rearward frame end; an extendable and retractable lift carriage connected with the base frame, wherein the lift carriage is comprised of a forward carriage end, a rearward carriage end, and an elongated trough; and a forward lifting mechanism for raising and lowering the forward carriage end relative to the base frame, wherein the forward lifting mechanism is comprised of:

2. The pipe handling apparatus as claimed in claim 1 wherein the forward lifting mechanism is configured so that the frame remote end of the lower lifting member and the carriage remote end of the upper lifting member are located between the forward jacking device and the rearward frame end.

3. The pipe handling apparatus as claimed in claim 1 wherein the lift carriage is comprised of a first carriage stage and a second carriage stage, wherein the carriage connection end of the upper lifting member is connected with the first carriage stage, wherein the second carriage stage is comprised of the elongated trough, and wherein the second carriage stage is extendable relative to the first carriage stage in a carriage extending direction away from the rearward carriage end and retractable relative to the first carriage stage in a carriage retracting direction toward the rearward carriage end.

4. The pipe handling apparatus as claimed in claim 1 , further comprising a skate apparatus which is configured to engage with a pipe joint positioned in the elongated trough in order to move the pipe joint along the elongated trough, wherein the skate apparatus is movable along the elongated trough.

5. The pipe handling apparatus as claimed in claim 4 wherein the skate apparatus is comprised of a gripping mechanism which is configured to grip the pipe joint so that the pipe joint can be moved along the elongated trough by the skate apparatus while being gripped by the gripping mechanism.

6. The pipe handling apparatus as claimed in claim 5 wherein the gripping mechanism is comprised of a first gripper section, a second gripper section and an actuatable gripper head operably connected with the first gripper section and the second gripper section, wherein the gripper head is actuated between a pipe gripping position and a pipe release position by relative movement between the first gripper section and the second gripper section.

7. The pipe handling apparatus as claimed in claim 6 wherein the skate apparatus is further comprised of a lower pipe joint support and wherein the gripping mechanism is configured to grip the pipe joint between the gripper head and the lower pipe joint support.

8. The pipe handling apparatus as claimed in claim 7 wherein the lower pipe joint support is comprised of a pipe shovel for scooping an end of the pipe joint from the elongated trough into engagement with the skate apparatus.

9. The pipe handling apparatus as claimed in claim 8 wherein the pipe shovel has a forward shovel end and wherein the forward shovel end is comprised of a tapered surface.

10. The pipe handling apparatus as claimed in claim 9 wherein the skate apparatus is further comprised of a transverse pipe joint support for engaging with the end of the pipe joint so that the skate apparatus can push the pipe joint along the elongated trough.

1 1. The pipe handling apparatus as claimed in claim 10 wherein the pipe shovel has a rearward shovel end and wherein the transverse pipe joint support is adjacent to the rearward shovel end.

12. The pipe handling apparatus as claimed in claim 7 wherein the skate apparatus is further comprised of a mechanical gripper linkage for operably connecting the gripper head with the first gripper section and the second gripper section.

13. The pipe handling apparatus as claimed in claim 12 wherein the first gripper section is reciprocably connected with the elongated trough, wherein the second gripper section is reciprocably connected with the elongated trough, and wherein the first gripper section is reciprocably connected with the second gripper section such that the first gripper section and the second gripper section are capable of reciprocating relative to each other along the elongated trough by an actuating amount of relative reciprocating movement.

14. The pipe handling apparatus as claimed in claim 13 wherein the first gripper section and the second gripper section each have a reciprocating resistance relative to the elongated trough, and wherein the reciprocating resistance of the second gripper section is greater than the reciprocating resistance of the first gripper section.

15. The pipe handling apparatus as claimed in claim 14 wherein the gripper head is actuated to the pipe gripping position by moving the first gripper section toward the rearward carriage end relative to the elongated trough, and wherein the gripper head is actuated to the pipe release position by moving the first gripper section toward the forward carriage end relative to the elongated trough.

16. The pipe handling apparatus as claimed in claim 1 , further comprising a rearward lifting mechanism for raising and lowering the rearward carriage end relative to the base frame.

17. The pipe handling apparatus as claimed in claim 16 wherein the rearward lifting mechanism is comprised of:

(i) a lifting member having a frame attachment end and a carriage attachment end, wherein the frame attachment end is pivotably connected with the base frame and wherein the carriage attachment end is pivotably connected with the lift carriage; and

(ii) an extendible and retractable rearward jacking device having a lower jack end and an upper jack end, wherein the lower jack end is pivotably connected with the base frame and wherein the upper jack end is pivotably connected with the lifting member at a location between the frame attachment end and the carriage attachment end.

18. The pipe handling apparatus as claimed in claim 17 wherein the rearward lifting mechanism is configured so that the rearward jacking device extends in a rearward jack extending direction toward the forward frame end and retracts in a rearward jack retracting direction toward the rearward frame end.

19. The pipe handling apparatus as claimed in claim 1 wherein the base frame has four corners and wherein the base frame defines a base frame bearing plane for engaging with a bearing surface, further comprising four lifting assemblies, wherein one of the lifting assemblies is associated with each of the four corners of the base frame, and wherein each of the lifting assemblies is comprised of a support leg having a bearing foot at a lower end of the support leg for engaging with the bearing surface, wherein the support leg is actuatable vertically between a fully retracted position in which the bearing foot is above the base frame bearing plane and a fully extended position in which the bearing foot is a lifting distance below the base frame bearing plane, and wherein the support leg is actuatable laterally between a fully retracted position in which the support leg is adjacent to the base frame and a fully extended position in which the support leg is a lateral clearance distance from the base frame.

20. The pipe handling apparatus as claimed in claim 19 wherein each of the lifting assemblies is further comprised of a device for actuating the support leg vertically and a device for actuating the support leg laterally. 21. The pipe handling apparatus as claimed in claim 20 wherein the device for actuating the support leg vertically is comprised of a vertical jacking device and wherein the device for actuating the support leg laterally is comprised of a lateral jacking device.

22. The pipe handling apparatus as claimed in claim 1 , further comprising a ramp having a lower ramp end and an upper ramp end, wherein the lower ramp end is pivotably connected with the forward frame end of the base frame, and wherein the ramp is extendable and retractable to vary the distance between the lower ramp end and the upper ramp end.

23. The pipe handling apparatus as claimed in claim 22 wherein the ramp is comprised of a lower ramp section, an upper ramp section which is extendable and retractable relative to the lower ramp section, and a ramp jacking device connected between the lower ramp section and the upper ramp section for extending and retracting the upper ramp section relative to the lower ramp section in order to extend and retract the ramp. 24. A pipe handling apparatus comprising:

(a) a base frame, wherein the base frame has a forward frame end and a rearward frame end; (b) a lift carriage connected with the base frame, wherein the lift carriage is comprised of a forward carriage end, a rearward carriage end, and an elongated trough;

(d) a skate apparatus which is configured to engage with a pipe joint positioned in the elongated trough in order to move the pipe joint along the elongated trough, wherein the skate apparatus is movable along the elongated trough, wherein the skate apparatus is comprised of a gripping mechanism which is configured to grip the pipe joint so that the pipe joint can be moved along the elongated trough by the skate apparatus, and wherein the gripping mechanism is comprised of a first gripper section, a second gripper section and an actuatable gripper head operably connected with the first gripper section and the second gripper section, wherein the gripper head is actuated between a pipe gripping position and a pipe release position by relative movement between the first gripper section and the second gripper section.

A pipe handling apparatus comprising: a base frame, wherein the base frame has a forward frame end, a rearward frame end, four corners, and defines a base frame bearing plane for engaging with a bearing surface; a lift carriage connected with the base frame, wherein the lift carriage is comprised of a forward carriage end, a rearward carriage end, and an elongated trough; a forward lifting mechanism for raising and lowering the forward carriage end relative to the base frame; and four lifting assemblies, wherein one of the lifting assemblies is associated with each of the four corners of the base frame, and wherein each of the lifting assemblies is comprised of a support leg having a bearing foot at a lower end of the support leg for engaging with the bearing surface, wherein the support leg is actuatable vertically between a fully retracted position in which the bearing foot is above the base frame bearing plane and a fully extended position in which the bearing foot is a lifting distance below the base frame bearing plane, and wherein the support leg is actuatable laterally between a fully retracted position in which the support leg is adjacent to the base frame and a fully extended position in which the support leg is a lateral clearance distance from the base frame.

26. A pipe handling apparatus comprising: a base frame, wherein the base frame has a forward frame end and a rearward frame end; an extendable and retractable lift carriage connected with the base frame, wherein the lift carriage is comprised of a forward carriage end, a rearward carriage end, and an elongated trough; a forward lifting mechanism for raising and lowering the forward carriage end relative to the base frame; and a rearward lifting mechanism for raising and lowering the rearward carriage end relative to the base frame.

The pipe handling apparatus as claimed in claim 26 wherein the forward lifting comprised of:

28. The pipe handling apparatus as claimed in claim 26, further comprising a skate apparatus which is configured to engage with a pipe joint positioned in the elongated trough in order to move the pipe joint along the elongated trough, wherein the skate apparatus is movable along the elongated trough, wherein the skate apparatus is comprised of a gripping mechanism which is configured to grip the pipe joint so that the pipe joint can be moved along the elongated trough by the skate apparatus, and wherein the gripping mechanism is comprised of a first gripper section, a second gripper section and an actuatable gripper head operably connected with the first gripper section and the second gripper section, wherein the gripper head is actuated between a pipe gripping position and a pipe release position by relative movement between the first gripper section and the second gripper section.

29. The pipe handling apparatus as claimed in claim 26 wherein the rearward lifting mechanism is comprised of: (i) a rearward lifting member having a frame attachment end and a carriage attachment end, wherein the frame attachment end is pivotably connected with the base frame and wherein the carriage attachment end is pivotably connected with the lift carriage; and (ii) an extendible and retractable rearward jacking device having a lower jack end and an upper jack end, wherein the lower jack end is pivotably connected with the base frame and wherein the upper jack end is pivotably connected with the rearward lifting member at a location between the frame attachment end and the carriage attachment end.

30. The pipe handling apparatus as claimed in claim 26 wherein the base frame has four corners and wherein the base frame defines a base frame bearing plane for engaging with a bearing surface, further comprising four lifting assemblies, wherein one of the lifting assemblies is associated with each of the four corners of the base frame, and wherein each of the lifting assemblies is comprised of a support leg having a bearing foot at a lower end of the support leg for engaging with the bearing surface, wherein the support leg is actuatable vertically between a fully retracted position in which the bearing foot is above the base frame bearing plane and a fully extended position in which the bearing foot is a lifting distance below the base frame bearing plane, and wherein the support leg is actuatable laterally between a fully retracted position in which the support leg is adjacent to the base frame and a fully extended position in which the support leg is a lateral clearance distance from the base frame.

31. The pipe handling apparatus as claimed in claim 26, further comprising a ramp having a lower ramp end and an upper ramp end, wherein the lower ramp end is pivotably connected with the forward frame end of the base frame, and wherein the ramp is extendable and retractable to vary the distance between the lower ramp end and the upper ramp end.