IES20110205A2

IES20110205A2 - A coupler

Info

Publication number: IES20110205A2
Application number: IE20110205A
Authority: IE
Inventors: James O'meara
Original assignee: James O'meara
Priority date: 2010-04-27
Filing date: 2011-04-27
Publication date: 2011-11-09
Also published as: GB2479890A; WO2011135525A2; IE20110207A1; GB201007008D0; WO2011135525A3

Abstract

A three-point coupler apparatus for connecting an implement to a vehicle comprises a substantially horizontal crossbeam (2) having an upper hook (3) for engaging an upper pin of a coupling device of an implement. The crossbeam (2) has a pair of laterally extendable/retractable arms (4) driven by an actuating means to increase or reduce the distance between opposite ends 5 of the arms 4. Each arm (4) comprises a substantially vertical support beam (7) comprising an extendable/retractable leg (8) having a lower hook (9) at its lower end (8a) for engaging a lower pin of the coupling device of an implement. The legs (8) are mutually substantially parallel and are simultaneously actuated by a single actuation mechanism to increase or reduce the distance between the lower hook (9) and the upper hook (3). A coupling sub-assembly (15) for coupling hydraulic or pneumatic conduits of the vehicle and the implement is also provided. <Figure 1>

Description

The present invention relates generally to a coupler apparatus for coupling an implement to a vehicle, e.g. an agricultural tractor, and in particular to a three-point coupler apparatus for coupling an implement to a vehicle.

Three-point couplers have been known since the 1960’s. One known three-point coupler, known as an U-coupler, comprises a rigid inverted "U" shaped frame and three hooks which receive the coupling pins of an implement. One hook is fixedly mounted at the apex portion of the inverted U shaped frame and one hook is fixedly mounted at the free end of each downwardly extending leg of the frame. When the hooks engage the coupling pins of the implement, each hook is locked in place with a wedge of steel that rotates to close the opening of the hook. This prevents the coupling pin from disengaging from the hook accidentally during use. To use this coupler, the sizes of the coupling mechanism of the implement and the coupler need to match. In order to couple the vehicle with an implement having the coupling mechanism of a different size, the coupler has to be replaced with a coupler that matches the size of the coupling mechanism of the implement.

Another known three-point coupler is known as an A-frame coupler and comprises a triangular frame fitted to the linkage of the vehicle. A second triangular frame is fixed to the implement and is configured to receive the frame fitted to the vehicle. A locking mechanism is used to secure the two frames together. A-frame couplers are commonly used for the mounting of implements to the front of a tractor due to lower stresses involved and reduced visibility of coupling points. A-frame couplers are relatively inexpensive to produce. Depending on the locking mechanism used, it is often necessary for the operator to leave the cab of the tractor to lock the coupler in place and couple the hydraulic services and drive shaft. Similar to the U-frame couplers, the dimensions of an A-frame coupler and the corresponding frame of the implement need to match and it is not possible to use the same A-frame with differently sized coupling frames of different implements.

Thus, current couplers have fixed position hooks and only fit implements that match these positions. Also, brackets, pins, or other locking mechanisms are required to secure the couplers to the implements.

US 7461702 (Farnsworth) describes a U-frame three-point coupler which has a horizontal cross sleeve member which has a pair of laterally telescopically mounted extension arms. The arms are hydraulically actuated to extend or retract laterally so as increase or reduce the overall length of the cross sleeve beam. A telescopically extendable leg extends downwardly from a free end of each arm. Each leg is independently actuated by a separately provided electric actuator to extend or to retract so as to increase or reduce vertical distance between the hook of a leg and the hook of the cross sleeve beam. Although this coupler is suitable for coupling with differently sized implements, the control arrangement of the arms and legs is complicated which makes adjustment of the arms and legs for the required position and engaging and disengaging the coupler to the implement cumbersome.

The object of the present invention is to mitigate the above disadvantages and to provide a universal three-point coupler apparatus without the above-mentioned disadvantages.

Accordingly, the present invention provides a three-point coupler apparatus for coupling a vehicle with a coupling device of an implement having an upper pin and a pair of laterally spaced apart lower pins, the coupler apparatus comprising a substantially horizontal cross beam bearing an upper hook for engaging an upper pin of the coupling device of an implement, the crossbeam comprising a pair of arms movably mounted on the crossbeam so as to extend or retract laterally in opposite directions with respect to the crossbeam thereby respectively increasing or reducing the distance between opposite ends of the arms, the arms being actuated by an actuation mechanism; each arm comprising a support beam, each support beam comprising a leg arranged substantially perpendicular to the crossbeam, the leg having a lower hook at its lower end for engaging a lower pin of the coupling device of an implement and the leg being movably coupled with the support beam so as to extend and retract substantially perpendicular to the crossbeam thereby respectively increasing or reducing the distance between the lower hook and the upper hook; wherein the legs are simultaneously actuated by a single actuation mechanism.

Advantageously, the upper hook and the lower hooks each comprise an opening for receiving a corresponding pin of a coupling device of an implement, wherein the opening IE 1 1 0 2 05 of the upper hook and the openings of the lower hooks face in opposite directions, wherein the actuating mechanism of the legs locks the legs when the upper hook and the lower hooks engage the respective pins of the coupling device of an implement, thereby locking the upper hook and the lower hooks in engagement with the respective pins.

Thus, no separate latching mechanism as used in known types of couplers is required. In one arrangement, the actuating mechanism positively forces the lower hooks into engagement with the respective pins, so that counteracting forces are applied by the upper hook and the lower hooks to the coupling device, to further secure the locking action. In one arrangement, the opening of the upper hook faces downwardly and the 10 openings of the lower hooks face upwardly, in which case a compressive force acts on the implement. The opening of the upper hook can also face upwardly and the openings of the lower hooks can face downwardly, in which case a tensile force acts on the implement.

In use, the coupler apparatus is attached to a vehicle, preferably, but not limited thereto, a rear of a vehicle. The coupler apparatus is preferably mounted to a three-point linkage assembly of the vehicle and coupled to a locator arm which replaces a top link of the three-point linkage, preferably a hydraulically or pneumatically actuated locator arm for moving the coupling apparatus with respect to the vehicle and an implement, and for 20 guiding the upper hook into engagement with an upper pin of the implement.

Advantageously, the actuating mechanisms are driven by a vehicle’s driving system, preferably a hydraulic or a pneumatic system and are controlled by a vehicle’s control means, ideally located in the cab of the vehicle. The actuating mechanisms can also be 25 electrical, mechanical or a combination of both.

The advantage of the coupler apparatus of the present invention is that and it fits almost all of the machinery in its category without the need to modify the coupler apparatus. The ability of the coupler apparatus to couple with differently sized coupling devices of various 30 implements makes it possible to use the coupler apparatus with different implements designed for different functions. Different mast and span dimensions of a coupling device sometimes are dictated by the function of an implement. For example, a machine that needs to be able to sway from side to side in relation to the longitudinal axis of the towing vehicle, e. g. a road sweeper that must be able to follow the vehicle around a corner while 35 remaining in contact with the ground, has a narrow span, whereas a wider span holds an implement more rigidly behind the vehicle during use. Similarly, a larger mast height allows the vehicle to lift a larger load whereas a shorter mast height gives a faster response in the change of angle of the implement as it is lifted from the ground. Since the coupler apparatus of the present invention adapts to match the span and mast of the implement, it is not limited to implements of a particular functionality.

A further advantage of the coupler apparatus of the present invention is that it enables the operator of a vehicle to attach implements to the vehicle without leaving the cab, thereby minimising the risk of injury.

The provision of a single actuating mechanism for the legs simplifies the design of the coupler apparatus and makes the adjustment of the vertical distance between the upper hook and lower hooks (the mast) a one step operation.

Advantageously, the actuating mechanism for actuating the legs of the coupler apparatus comprises a pressure relief system so that the lower hooks of the legs can adapt to implements with lower pins which are staggered in the vertical direction. The pressure relief system allows one leg to move independently of the other if the other leg has encountered sufficient resistance from its respective lower pin.

The present invention also provides a coupling sub-assembly for coupling hydraulic or pneumatic conduits of an implement to the hydraulic or pneumatic conduits of a vehicle. The coupling sub-assembly comprises a first support bracket provided on the crossbeam of the coupler apparatus which supports one or more female (or male) hydraulic or pneumatic fittings for coupling with a hydraulic or pneumatic conduit of the vehicle. A second support bracket is provided adjacent an upper pin of a coupling device of an implement, the second support bracket supporting one or more male (or female) fittings for coupling with a hydraulic or pneumatic conduit of the implement. The first and the second support brackets and their respective male/female fittings are positioned with respect to each other so that as the upper hook of the crossbeam engages the upper pin of the implement, the fittings on the supports brackets are guided into engagement with each other thereby connecting the conduits of the implement and of the vehicle. Conversely, the fittings are automatically disconnected as the upper hook is disengaged from the upper pin and the conduits of the implement and the vehicle are disconnected.

Preferably, the coupling sub-assembly includes an upper pin for a coupling device of an implement, the upper pin being assembled with the second bracket, and a fastening means for fitting the upper pin together with the second bracket to the required location on the coupling device. In one arrangement, the fastening means comprises a single bolt.

The advantage of the coupling sub-assembly is that it provides for the connection of the hydraulic or pneumatic conduits of a vehicle and an implement automatically and simultaneously with the engagement of the vehicles coupling apparatus with the coupling device of the implement and does not require the operator to leave the cab to lock it in place. A further advantage of the subassembly is that it allows for coupling of the hydraulic or pneumatic conduits while still retaining compatibility with standard connections. The conduit of the implement can also be manually connected to the fitting on the first bracket on the crossbeam of the coupler apparatus without modification to the conduit of the implement.

In one variation, the coupler apparatus includes a mounting bracket configured for receiving and holding an upper pin of an implement, the mounting bracket being adapted to be mounted on an implement so as to hold an upper pin in the correct position on the implement. The mounting bracket is used to provide a mounting position for an upper pin on an implement in case the implement only includes two lower pins, thereby providing a third coupling point for coupling with the upper hook of the coupler apparatus. For example, a typical mower usually comprises only two lower brackets. In order to provide a position for an upper pin, the mounting bracket is fixed to a headstock of the mower, and an upper pin is then fixed on the mounting bracket, thereby providing the third coupling point. The mounting bracket can also form part of the above-described coupling subassembly and can be coupled with the second bracket of the coupling sub-assembly.

Preferably, the arms of the coupler apparatus are simultaneously actuated by the actuation mechanism.

Ideally, the legs are mutually substantially parallel and substantially perpendicular to the crossbeam.

Preferably, the support beam is provided in the form of a vertically oriented sleeve.

IE 1 1 0 2 0 5 Preferably, the crossbeam is provided in the form of a horizontally oriented sleeve.

Herein, the terms "rear", "front", "forwardly", "rearwardly", "laterally or the like are used in relation to the direction of a forward movement of the relevant vehicle. The terms "upper’, "lower, "upwardly", "downwardly, "horizontal", "vertical" or the like are related to a ground surface on which the vehicle is based.

As discussed above, the coupler apparatus of the present invention is suited for use in conjunction with agricultural vehicles, such as tractors, for coupling an implement to the vehicle. It will be appreciated that the use of the coupler apparatus is not limited to the use with agricultural vehicles only. Uses of the coupler apparatus of the invention with other types of machinery will be readily apparent to persons skilled in the art.

The invention will now be described with reference to the accompanying drawings which show by way of an example an embodiment of the coupler apparatus of the invention. In the drawings: Figure 1 is a perspective view of a coupler apparatus of the present invention in a retracted mode; Figure 2 is an exploded perspective view of the coupler apparatus of Figure 1; Figure 3 is an elevation of the coupler apparatus of Figure 1; Figure 4 is an exploded elevation of the coupler apparatus of Figure 1; Figure 5 is a side elevation of the coupler apparatus of Figure 1; Figure 6 is a top view of the coupler apparatus of Figure 1; Figure 7 is a perspective view of a coupling sub-assembly of the invention in a disengaged mode; Figure 8 is a perspective view of the coupling sub-assembly of Figure 7 in an engaged mode; and Figure 9 is a perspective view of a mounting bracket for providing a mounting location for an upper pin for an Implement, where the implement initially only includes two lower pins.

Referring to Figures 1 to 6, a three-point coupler apparatus of the invention is indicated generally by reference numeral 1. The coupler apparatus 1 is designed for coupling a IE 1 1 0 2 0 5 vehicle with a coupling device of an implement (not shown) having an upper pin and a pair of laterally spaced apart lower pins.

The coupler apparatus comprises a substantially horizontal crossbeam 2 provided in the 5 form of a sleeve. The crossbeam 2 bears a centrally mounted upper hook 3 for engaging an upper pin of the coupling device of an implement. A pair of arms 4 are engaged with the crossbeam 2 to slidably move inside the sleeve so as to extend or retract laterally in opposite directions with respect to the crossbeam thereby respectively increasing or reducing the distance between opposite ends 5 of the arms 4. The arms are 10 simultaneously actuated by an actuation mechanism provided inside the sleeve of the crossbeam 2.

Each arm 4 comprises a substantially vertical support beam 7. Each support beam 7 is provided in the form of a sleeve for slidably receiving a leg 8 extending substantially 15 perpendicular to the crossbeam 2. Each leg 8 has a lower hook 9 at its lower end 8a for engaging a lower pin of the coupling device of an implement. Each leg 8 is slidably movably coupled with its support beam 7 so as to extend and retract substantially perpendicular to the crossbeam 2 thereby respectively increasing or reducing the distance between the lower hook 9 and the upper hook 3. The legs 8 are mutually substantially 20 parallel and are simultaneously actuated by a single actuation mechanism (not shown).

The upper hook 3 and the lower hooks 9 each comprise an opening 10 for receiving a corresponding pin of a coupling device of an implement. The opening 10 of the upper hook 3 faces downwardly and the openings 10 of the lower hooks 9 face in opposite 25 direction, i.e. upwardly. When the upper hook 3 and the lower hooks 9 engage the respective pins of the coupling device of an implement, the actuating mechanism of the legs 8 locks the legs 8 in position, thereby locking the upper hook 3 and the lower hooks 9 in engagement with the respective pins. Accordingly, no separate latching mechanism as used in known types of couplers is required. The actuating mechanism can be arranged 30 to positively force the lower hooks 9 into engagement with the respective pins of the coupling device of the implement, so that a compressive force acting between the upper hook 3 and the lower hooks 9 is applied the coupling device, thereby further securing the locking.

IE 1 1 0 2 05 In use the coupler apparatus 1 is attached to a vehicle (not shown), preferably, but not limited thereto, a rear of a vehicle. The coupler apparatus 1 is mounted to a three-point linkage assembly (not shown) of the vehicle which comprises a hydraulically or pneumatically actuated locator arm 12 for moving the coupling apparatus 1 with respect to 5 the vehicle and an implement and for guiding the upper hook 3 into engagement with an upper pin of the implement.

The actuating mechanisms of the arms 4 and the legs 8 are driven by the vehicle’s driving system, which is typically a hydraulic or a pneumatic system and are controlled by a 10 vehicle’s control means located in the cab of the vehicle.

In use, the operator in the cab of the vehicle actuates and controls the locator arm 12, which aligns the coupler apparatus with the coupling device of the implement and subsequently causes the upper hook 3 to engage the upper pin of the coupling device. 15 The operator also controls the actuating mechanism of the arms 4 to establish the required distance between the lower hooks 9. The operator then controls the actuating mechanism of the legs 8 so as to firstly extend the legs 8 to position the lower hooks below the level of the lower pins of the coupling device of the implement. The legs 8 are subsequently lifted (retracted) so as to engage the lower pins thereby also achieving the 20 necessary distance between the upper hook 3 and the lower hooks 9.

Figures 7 and 8 show a coupling sub-assembly 15 for coupling hydraulic or pneumatic conduits of an implement to the hydraulic or pneumatic conduits of the vehicle. The coupling sub-assembly 15 comprises a first support bracket 16 fixed to the crossbeam 2 25 of the coupler apparatus 1. The first bracket 16 supports a pair of female hydraulic or pneumatic fittings 17 for coupling with a hydraulic or pneumatic conduit (not shown) of the vehicle. A second support bracket 18 is assembled with an upper pin 19 for mounting on a coupling device of an implement. The second support bracket 19 supports a pair of male hydraulic or pneumatic fittings 20 for coupling with a hydraulic or pneumatic conduit 30 (not shown) of the implement. The first and the second support brackets 16, 18 and their respective fittings 17, 20 are positioned with respect to each other so that as the upper hook 3 of the crossbeam 2 engages the upper pin 19 of the implement, the fittings 17, 20 on the supports brackets 16, 18 are guided into engagement with each other thereby connecting the conduits of the implement and of the vehicle. The fittings 17, 20 are IE 1 1 0 2 05 automatically disconnected as the upper hook 3 is disengaged from the upper pin 19 thereby disconnecting the conduits of the implement and the vehicle.

A fastening means (not shown) is provided, e.g. one or more bolt for fitting the upper pin 3 5 assembled with the second bracket 18 to the required location on the coupling device.

As shown in Figure 9, one variation of the coupler apparatus includes a mounting bracket configured for receiving and holding an upper pin (not shown) of an implement The mounting bracket 25 is adapted to be mounted on an implement so as to hold an upper 10 pin in the correct position on the implement. The mounting bracket 25 is used to provide a mounting position for an upper pin on an implement in case the implement only includes two lower pins, thereby providing a third coupling point for coupling with the upper hook 3 of the coupler apparatus 1. For example, a typical mower usually comprises only two lower brackets. In order to provide a position for an upper pin, the mounting bracket 25 is 15 fixed to a headstock 26 of the mower, and an upper pin is then fixed on the mounting bracket 25, thereby providing the third coupling point. The mounting bracket can also form part of the coupling sub-assembly 15 and can be coupled with the second bracket 18 of the coupling sub-assembly 15.

The present invention is defined in the appended claims, the foregoing description of the preferred embodiments being provided merely for the purpose of illustration of the disclosure. Persons skilled in the art will appreciate that various modifications of the above-described embodiments not explicitly described herein are possible within the scope of the appended claims.

Claims

CLAIMS:

1. A three-point coupler apparatus for coupling a vehicle with a coupling device of an implement having an upper pin and a pair of laterally spaced apart lower pins, the coupler apparatus comprising a substantially horizontal cross beam bearing an upper hook for engaging an upper pin of the coupling device of an implement, the crossbeam comprising a pair of arms movably mounted on the crossbeam so as to extend or retract laterally in opposite directions with respect to the crossbeam thereby respectively increasing or reducing the distance between opposite ends of the arms, the arms being actuated by an actuation mechanism; each arm comprising a support beam, each support beam comprising a leg arranged substantially perpendicular to the crossbeam, the leg having a lower hook at its lower end for engaging a lower pin of the coupling device of an implement and the leg being movably coupled with the support beam so as to extend and retract substantially perpendicular to the crossbeam thereby respectively increasing or reducing the distance between the lower hook and the upper hook; wherein the legs are simultaneously actuated by a single actuation mechanism.

2. A coupler apparatus as claimed in Claim 1, wherein the arms of the coupler apparatus are simultaneously actuated by the actuation mechanism; optionally, wherein the upper hook and the lower hooks each comprise an opening for receiving a corresponding pin of a coupling device of an implement, wherein the opening of the upper hook and the openings of the lower hooks face in opposite directions, wherein the actuating mechanism of the legs is operable to lock the legs in position when the upper hook and the lower hooks engage the respective pins of the coupling device of an implement, thereby locking the upper hook and the lower hooks in engagement with the respective pins; wherein the actuating mechanism is operable to positively force the lower hooks into engagement with the respective pins, so that counteracting forces are applied by the upper hook and the lower hooks to the coupling device, to further secure the locking action; and wherein the opening of the upper hook faces downwardly and the openings of the lower hooks face upwardly, so that a compressive force acts on the implement or wherein the opening of the upper hook face upwardly and the openings of the lower hooks face downwardly, so that a tensile force acts on the implement; IE 1 1 0 205 optionally, wherein in use the coupler apparatus is attached to a vehicle; optionally, wherein the coupler apparatus is mounted to a three-point linkage assembly of a vehicle which includes a locator arm for moving the coupling apparatus with respect to the vehicle and an implement and for guiding the upper hook into engagement 5 with an upper pin of the implement; optionally, wherein the actuating mechanisms of the arms and the legs are driven by a vehicle’s driving system; optionally, wherein the actuating mechanisms of the arms and the legs are driven by a hydraulic or a pneumatic system; io optionally, wherein the actuating mechanisms of the arms and the legs and are controlled by a vehicle’s control means; optionally, wherein the actuating mechanisms of the arms and the legs and are controlled by a vehicle’s control means and wherein vehicle’s control means is located in the cab of the vehicle; 15 optionally, wherein the legs are mutually substantially parallel and substantially perpendicular to the crossbeam; optionally, wherein the support beam is provided in the form of a vertically oriented sleeve; optionally, wherein the crossbeam is provided in the form of a horizontally oriented 20 sleeve; and optionally, wherein the actuating mechanism for actuating the legs of the coupler apparatus comprises a pressure relief system so that the lower hooks of the legs can adapt to implements with lower pins which are staggered in the vertical direction; and wherein the pressure relief system is operable to control one leg to move independently of 25 the other if the other leg has encountered sufficient resistance from its respective lower pin.

3. A coupler apparatus as claimed in Claim 1 or Claim 2, wherein the coupler apparatus comprises a coupling sub-assembly for coupling hydraulic or pneumatic 30 conduits of an implement to the hydraulic or pneumatic conduits of a vehicle, wherein the coupling sub-assembly comprises a first support bracket provided on the crossbeam of the coupler apparatus which supports one or more female or male hydraulic or pneumatic fittings for coupling with a hydraulic or pneumatic conduit of the vehicle, wherein a second support bracket is provided adjacent an upper pin of a coupling device of an implement, 35 the second support bracket supporting one or more male or female fittings for coupling IE 1 1 0 2 05 with a hydraulic or pneumatic conduit of the implement, wherein the first and the second support brackets and their respective male or female fittings are positioned with respect to each other so that as the upper hook of the crossbeam engages the upper pin of the implement, the fittings on the supports brackets are guided into engagement with each 5 other thereby connecting the conduits of the implement and of the vehicle; and wherein the fittings are automatically disconnected as the upper hook is disengaged from the upper pin and the conduits of the implement and the vehicle are disconnected; optionally, wherein the coupling sub-assembly includes an upper pin for mounting on a coupling device of an implement, the upper pin being assembled with the second 10 bracket. optionally, wherein the coupler apparatus includes a mounting bracket configured for receiving and holding an upper pin of an implement, the mounting bracket being adapted to be mounted on an implement so as to hold an upper pin in the correct position on the implement, thereby providing a third coupling point for coupling with the upper hook 15 of the coupler apparatus for an implement which only includes two lower pins; and wherein the mounting bracket is coupled with the second bracket of the coupling subassembly; and optionally, wherein a fastening means is provided for fitting the upper pin assembled with the second bracket to the required location on the coupling device.

4. A coupling sub-assembly for coupling hydraulic or pneumatic conduits of an implement to the hydraulic or pneumatic conduits of a vehicle, the coupling sub-assembly comprises a first support bracket provided on a crossbeam of a three-point coupler apparatus for coupling a vehicle with a coupling device of an implement having an upper 25 pin and a pair of laterally spaced apart lower pins, wherein the first bracket which supports one or more female or male hydraulic or pneumatic fittings for coupling with a hydraulic or pneumatic conduit of the vehicle, wherein a second support bracket is provided adjacent an upper pin of a coupling device of an implement, the second support bracket supporting one or more male or female fittings for coupling with a hydraulic or pneumatic conduit of 30 the implement, wherein the first and the second support brackets and their respective male or female fittings are positioned with respect to each other so that as a hook of the crossbeam engages the upper pin of the implement, the fittings on the supports brackets are guided into engagement with each other thereby connecting the conduits of the implement and of the vehicle; and wherein the fittings are automatically disconnected as IE 1 1 Ο 2 Ο 5 the hook is disengaged from the upper pin and the conduits of the implement and the vehicle are disconnected; optionally, wherein the coupling sub-assembly includes an upper pin for mounting on a coupling device of an implement, the upper pin being assembled with the second 5 bracket; and, wherein a fastening means is provided for fitting the upper pin assembled with the second bracket to the required location on the coupling device; and optionally, wherein the coupler apparatus includes a mounting bracket configured for receiving and holding an upper pin of an implement, the mounting bracket being adapted to be mounted on an implement so as to hold an upper pin in the correct position 10 on the implement, thereby providing a third coupling point for coupling with the upper hook of the coupler apparatus for an implement which only includes two lower pins; and wherein the mounting bracket is coupled with the second bracket of the coupling subassembly. 15

5. A coupler apparatus or a coupling sub-assembly substantially in accordance with any of the embodiments as herein described with reference to and/or as shown in the accompanying drawings.