GB2198101A - Articulated oar - Google Patents

Abstract

, An articulated oar which is so constructed that its blade 7 operates at all times at right angles to the keel line of a boat. This is achieved by securing the blade 7 at right angles to a follower 5 which pivots on a vertical axis on the outboard end of the loom 3, and whose attitude is controlled by a messenger 4 of the same length as the loom 3. Inboard ends of loom 3 and messenger 4 are secured to a leader 2 of the same length as follower 5: thus the four components loom 3 messenger 4, leader 2 and follower 5 form the four sides of a flexible parallelogram. Since the leader 2 is attached to the boat parallel to the keel line, the follower 5 will be maintained parallel to the keel line also, and the blade 7 will at all times operate at all times at right angles to the keel line. <IMAGE>

Description

ARTICULATED OAR This invention relates to an articulated oar.

Oars have been in use for millenia as a means of propelling boats large and small. adhere a single oar is used it is sometimes called a sweep, and where a pair are used they might be referred to as sculls; their function however, is the same.

A typical oar consists of a simple pole, the loom, with a handle on the inboard end and a blade on the outboard end. The loom rests iri a crotch fastened to a thole pin, the warlock or rowlock; this in turn fits into a hole, the thole, created in the g@@wale of the boat for this purpose.

Using the oar as a lever, the boat is propelled forward by dipping the blade into the water ard hauling on the oar handles, thus imparting propulsive effort to the gunwale.

Because the blade and loom are fixed in lire, the blade describes an arc through the water, and cannot remain perpendicular to the keel line of the boat. At the beginning and end of the rowing stroke the blade is putting more effort into moving the boat sideways titan in the desired direction. The greater the arc of stroke used i.e. by such means as a sliding seat, then the greater the loss of efficiency.

According to the present invention there is provided an oar with a blade pivoting in a vertical axis with means to keep it at all times in an attitude at right angles to the keel line of the boat.

Further, means are provided to assist release of the blade from the water by hingeing it in the horizontal axis, and a rear view mirror of constant incidence is also included.

A specific embodiment of the invention will nov be described by way of example with reference to the accompanying drawings in which: Figure 1 shows in perspective, the oar in position on the boat.

Figure 2 snows in half plan the respective attitudes of the parts of the oar at var-cus stages of the rowing stroke.

Figure 3 shows in perspective an alternative method of construction and operation of the inboard end of the oar shown in Fig. 1 Figure 4 shows as schematic diagram an alternative method cf applying the sane inventive principle.

Figure 5 shows the oar depicted in Fig. 4 as it might appear in perspective and with some idea of proportion.

Referring to the drawings, the oar comprises a loom 3 flexibly attached to a leader 2 which is suitably mounted on the gunwale 1 of a typical boat. A messenger 4 flexibly attached to the leader 2 operates in parallel to the loom 3, and both terminate via appropriate connections 8 to a follower 5. A blade 7 is fixed at right angles to the follower 5. provision is made for one cr moie idlers G to bridge with suitable connections between loom 3 and messenger 4.

The oar is used in the usual manner; the operator pressing down cn the inboard end as he reaches forward to raise the blade from the water te the back sweep, and then pulling on the handle to propel the boat through the water. With the invention illustrated in Fig. 1 the loom 3 a.d the messenger 4 remain parallel at all tiues as do the leader 2 and tlie follower 5. Fig. 2 shows in half plan the relationship of the various components to the line of the keel 11 during a random six stages of the rowing cycle.

In order to give the operator a practic@@ view to his rear, advantarre may be taker, of the parallel motion t side a suitable mirror 10 carried on an idler 6 at a position to suit the operator.

In order to facilitate release from the water at the end of the power stroke, tiie blade 7 ray have a hinge 12 added at a suitable position together with a device to limit movement of the hinged area. Figure 3 shows an alternative construction for the inboard ends of loom 3 and messenger 4 which are connected by a suitable link 13 which carries a handle 14. The parallel motion is thus continued to the handle 14 which will remain at right angles to the keel at all tines. In this circumstance loom 3 atd messenger 4 may be mcre or less equal in section. In Fig. 4 a schematic diagram is shown offering a different method of applying the same principle.

here, twin wire cables are the messengers 16 working or; capstans 15 contained within the hollow loom 3 of the oar. Fig. 5 shows the method used in Fig. 4 in perspective.

Claims (12)

1. An articulated oar comprising of a loom with a blade which swivels in the verticel axis and whose attitude is maintained at right angles to the keel of the boat by means of a messenger operating between a leader arm and a follower arm; the loom and messenger, leader ard follower forming the four sides of a flexible parallelogram.

2. An articulated oar as claimed in claim 1 whereby the messenger is continued inb@@rd of the gunwale tG be linked to the inbord end of the loon and a handle placed thereon, so trat the handle remains at right angles to the keel at all times and thus parallel to the blade.

3. An articulated oar as claimed in claim 1 or claim. 2 but with to @essengers, one on either side cf the loom.

4. An articulated oar as claimed in claims 1 to 3 whereby the constant angle of the blade and/or the handle may be maintained by wire cables working within the hollow loon of the oar.

5. An articulated oar as claimed in claims 1 to M whereby the constant angle of the blade and/or handle may be maintained by hydraulic devices contained within the hollow loo of the oar.

6. An articulated oar as claimed in claims 1 to 5 whereby the blade may be more or less balanced in frontal area about the vertical pivot axis.

7. n articulated oar as claimed in clains 1 to 6 whereby the blade may be constructed to Dive negative, neutral or positve buoyarcy.

8. An articulated oar as claimed in claims 1 to 7 whereby part of the blade may be @irged in a horizontal axis to assist relcase from the water

9. An articulated oar as claimed in claims 1 to 8 whereby the leader arm nay be adjusted for lonOitudinal line so that it might lie parallel to the keel line where the gunwale does not do so.

10. An articulated oar as claimed in claims 1 to 9 whereby a mirror of constant incidence is carried by idler or capstan as might be appropriate.

11. A mirror as claimed in claim 10 whereby a differential motion is imparted to give a more ideal rear view.

12. An articulated oar substantially as described herein with reference to figures 1 to 5 of the accompanying drawings.