WO2015187108A1

WO2015187108A1 - A speargun with horizontal rollers design and its innovative counteracting operation principle

Info

Publication number: WO2015187108A1
Application number: PCT/TR2015/000239
Authority: WO
Inventors: Cafer MUGLA; Onur ERGUN
Original assignee: Apnea Deniz Malzemeleri Plastik Turizm Sanayi Ve Ticaret Limited Şirketi
Priority date: 2014-06-06
Filing date: 2015-05-28
Publication date: 2015-12-10

Abstract

This invention is regarding the construction of a new spear-gun to be used for hunting underwater. It includes a set of innovations for enabling easier movement on the horizontal axis, having less recoil, loading by leg power and disengaging without frightening the prey. The invention particularly focuses on the construction of the speargun to provide a low recoil thanks to its horizontal rollers located on its tip, which inverts the direction of the force created by the bands. The projectile, pulled by the shaft cords, accelerates in the counter direction.

Description

A SPEARGUN WITH HORIZONTAL ROLLERS DESIGN AND ITS INNOVATIVE COUNTERACTING

OPERATION PRINCIPLE INTRODUCTION

This invention is regarding the construction of a new spear-gun to be used for hunting underwater, it includes a set of innovations for enabling easier movement on the horizontal axis, having less recoil, loading by leg power and disengaging without startling the prey.

The invention particularly focuses on the construction of the speargun to provide a low recoil thanks to its horizontal rollers located on its tip, which inverts the direction of the force created by the bands. The projectile, pulled by the shaft cords, accelerates in the counter direction.

STATE OF THE ART The rubber band powered spear guns are widely used for underwater hunting. Their operational principles generally share common features. To name a few, they employ loose rubber bands located on the tip of the speargun. These rubber bands provide the power to accelerate the shaft (a.k.a the spear) during the shot. The part located on the rear end of the bands is called "wishbone". The wishbone holds the bands stretched when the spear gun is loaded and connects the rear ends of the bands. The body is located between the tip (will be referred to as 'head part' from now on) and the handle. The body provides buoyancy in the water, while enduring the force of the stretched bands. The handle located at the back of the body is used for handling of the speargun. The handle also functions as a supporting surface, while the person (will be referred as the 'user' from now on) pushes the rear end of the handle against her/his chest while loading the spear gun. There is also a trigger mechanism housing in the handle. The trigger mechanism is located inside this housing. Trigger is a part of the mechanism, which is pulled for releasing the spear. The shaft constitutes the projectile, which is commonly made of metal with a pointed tip. The Spear is usually longer than the body and enclosed inside a shaft guide, if there is one. There is a trigger notch at the rear end with an appropriate shape in order to be attached to the trigger mechanism. Also, there are wishbone notches or shark tabs to hold the wishbone at the rear end of the shaft. The barb is to prevent the loss of the prey and located in the front end of the shaft. Shooting line is for the shaft to the speargun. This line is attached to a line hole which is at the rear end of the shaft. The line release part which is a pawl located on the handle, releases the shooting line when the trigger pulled. The body, head part and handle can be a single piece, or separate parts depending on the design of the speargun.

To load the speargun, the user places the shaft to the trigger mechanism and makes sure that it clicks in place, then rigs the shooting line by folding it from the head part to the line release part several times. After that, pushes the rear side of the handle to his chest, pulls the bands towards him/herself and loads the spear gun by attaching the wishbone to one of the notches or shark tabs. This effort may cause bruises and pain especially after repetitive shots. The spear is released when the trigger is pulled and projected forward by using the potential energy stored in the rubber bands. One way to increase the power and range of the speargun is to make it longer, however a longer speargun will be heavier and more cumbersome especially on the horizontal axis. The longer the spear gun is, the more the distance between the center of gravity and the handle will be, increasing the tension on the hunter's wrist while the spear gun is being rotated. A bigger spear gun would also need to be thicker to proportionally endure the increased load. The bands also need be thicker time to provide necessary power and speed to the longer and heavier spear. In an ordinary speargun, the release of the spear generates a significant recoil, since the bands and the projectile move together to the same direction. Moreover, the increased pulling distance for the rubber band may require muscle strengths and arm lengths exceeding the users' capacity. Another problem that all of the ordinary spearguns face is the pressure wave generated by the the band splash during their sudden deceleration just after returning to their original length. Most of the prey can sense this pressure, triggering an escape reflex. As the shot distance grows, so do the chances for the prey to escape.

As another problem this invention addresses, the wishbone notches or shark tabs on the shafts make an attachment point that is few millimeters off the midline. This situation causes a wobbling during the sudden acceleration of the shaft. Adding a shaft guide to decrease this wobbling increases the friction and limits the speed of the shaft.

Likewise, the wishbone notches constitute weak spots on the spear. Shafts with shark tabs don't have these weak spots, but they have increased drag and they damage the flesh once they penetrate the prey.

The bands cannot pull the projectile after returning to their original lengths. Thus approximately one third of the body length is lost in means of spear acceleration. The solution proposed against this problem is using vertical rollers at the head part, rotating the front end of the bands to the down side of the body. This way, shaft can be pulled throughout the entire body length. However, the bands that are rotated around vertical rollers makes the spear gun thicker and horizontal rotations become more difficult. These rollerguns are also more difficult to load, thus have not gained a widespread use.

THE AIM OF THE INVENTION With the use of horizontal rollers, this design reaches a hydrodynamic and slim shape to minimize the drag on the horizontal plane, by using a shaft cord that is rotated around the roller hole, instead of the band itself. This makes it possible to use thinner rollers with larger diameters thus decreasing thickness of the head part.

This design also allows for using a longer band compared to a standard spear gun of the same length, by attaching stretched bands on the rear end of the body instead of the shaft. As an added benefit, , bands can fully utilize the entire stretch distance to accelerate the spear, due to the use of horizontal rollers. This design innovation allows for shorter spears to be accelerated using the energy by longer and thicker bands, in comparison to existing designs. This provides the speargun with the power and the range of a much longer ordinary band powered speargun. Also, this mechanism enables the handle and the trigger mechanism to be placed in the middle closer to center of gravity. So, a very high horizontal maneuver ability is achieved During the shot, a significant portion of the recoil force is dampened by the front ends of the band, which move in the opposite direction of the acceleration of the spear. Moreover, holding the speargun at a point much closer to the center of gravity facilitates the control of the remaining recoil energy. One of the major objectives of the invention is to prevent the splashing effect caused by released bands, which may alert the prey to flee. The bands and the shaft cord make a closed loop and at the end of the shot, when the bands return to their original lenght, the shaft cord becomes stretched. By preventing the splash this way, this design reduces the the pressure wave to levels that will not be felt by the prey. Another major aim of the invention is to enable the speargun to be loaded by leg force. The user can get support from the speargun's head part to use his/her leg muscles. This also allows for using much thicker bands that would otherwise cause bruises and pain on the chest if arm force were being used.

Another benefit of this invention is to minimize the shaft wobbling due to the sudden acceleration of a quite long shaft that is pulled from the midline, as is the case with the standard spearguns. These wobbling is reduced significantly thanks to a considerably shorter spear which is pulled from the midline. Thus, the accuracy is increased and the drag of the shaft is reduced. Moreover, the durability of the spear is increased due to its short and non-notched design.

THE FIGURES THAT WILL HELP THE INVENTION TO BE UNDERSTOOD

Figure - 1; Rear perspective view of the loaded speargun with dual bands configuration.

Figure - 2; Top perspective view of the loaded speargun with dual bands configuration. Note that the upper half of the head part is removed. Figure - 3; Top perspective view of the loaded speargun with dual bands configuration. Note that the body and the head part is removed. Figure - 4; Top perspective view of the loaded speargun with single circular band confguration. Note that the upper half of the head part is removed.

Figure - 5; Top perspective view of the loaded speargun with the single circular band configuration.

Figure - 6; Rear perspective view of the loaded speargun without rubber bands or shaft cords.

Figure - 7; Side view of the speargun shaft. Figure - 8; The rear end of the shaft in detail.

Figure - 9; Top view of the speargun with dual bands configuration. The sections are taken from the marked intersection plane. In the "Section A", the shooting line housing is full of rigged shooting line. In "Section B" the shooting line housing is empty.

Figure - 10; Counteracting operation principle of the dynamic parts during the shot. Note that the rollers change the direction of the force created by the band pull. The projectile, pulled by the shaft cords, accelerates in counter direction.

REFERENCE NUMBERS

10. Body of the spear gun

11. Shooting line cavity

20. Handle

30. Trigger mechanism

31. Trigger

40. Head part

41. Edge of the head part

50. Enclosed shaft guide

60. Shaft

61. Trigger notch 62. Shaft cord notch

70. Rubber band

71. Shaft cord

72. Wishbone cord

80. Horizontal roller

90. Shooting line

The invention will be better understood with the attached figures and reference numbers given above.

DETAILED DESCRIPTION OF THE INVENTION

!n Figure - 1; the rear perspective view of a loaded speargun with dual rubber band{70) configuration is shown. In Figure - 2; the top perspective view of a loaded speargun with dual rubber band(70) configuration is shown, upper half of the head part(40) is omitted for demonstration purposes. In Figure - 3; the dual rubber band (70) system of a loaded speargun is seen from the rear perspective. In Figure - 4 the top perspective view of a loaded speargun with single circular band(70) configuration is shown, upper half of the head part is omitted for demonstration purposes. In Figure - 5; the single circular rubber band (70) system of a loaded speargun is seen from the rear perspective. In Figure 6 the speargun is seen without rubber bands (70) or shaft cords (71). The speargun offers two configuration options. The first one is the "dual rubber band (70)" configuration, in which the wishbone cord (72) connects the posterior ends of the rubber bands (70) and when loading the speargun the wishbone cord (72) is attached to the rear end of the body(10). n in the second "single circular band (70)" configuration, a single piece of rubber is used and the single circular band (70) itself is attached to the rear end of the body.

In summary, the rear surface of the head part (40) serves a double function as a footstep to load the speargun. The horizontal rollers (80) are positioned inside the head part (40). The shaft cord (71) links the front ends of the rubber bands (70) and inverts direction around the horizontal rollers (80). Therefore, backwards movement of the front end of the rubber bands (70) pulls the shaft (60) forward. The purpose of the horizontal rollers (80) is to invert the direction of the band pull force towards the counter direction with minimal friction. The rubber bands (70) are located on both sides of the speargun body (10). In the loaded configuration, the shaft cord (71) is located on both sides of the shaft (60) inside the enclosed shaft guide (50). Shaft cord (71) is attached to the shaft cord notch (62) which is located on the rear end of the shaft (71). In this way, the shaft cord (71) connects the front ends of the rubber band (70) to the rear end of the shaft (60). The wishbone cord (72) links the rear ends of the rubbers (70) if the "dual rubber bands (70)" configuration is preferred. It is attached to the rear end of the speargun body (10) when the speargun is loaded. There is no wishbone cord (72) in the single circular rubber band(70) configuration. The shaft (60) is located in the enclosed shaft guide (50) of the the loaded speargun. The shaft (60) has a trigger notch (61) attached to the trigger mechanism (30). The shaft (60) has a shaft cord notch (62) at its rear end. This notch is at the midline of the shaft in the longitudinal axis. The details about the shaft (60) are depicted in Figure 7 and Figure 8. The spear gun body (10) lays between the spear gun head part (40) and the rear end of the speargun. This spear gun body (10) provides enough buoyancy in water to keep the speargun afloat. Moreover, it is designed to be strong enough to endure the force of the stretched rubber bands (70). Horizontal movements of the spear gun in the water is easier compared to conventional designs due to the hydrodynamic shape of the speargun head part's edge (41) and the speargun body (10). The handle (20) is located under the spear gun body (10) on the middle section. The trigger mechanism (30) is also located on the handle (20). Trigger (31) itself is a part of the trigger mechanism, and pulled to release the shaft (60). Shooting line cavity (11) is an empty space along the shaft's (60) upper surface where the rigged shooting line (90) is located. Shooting line (90) is released with the trigger pull by the shooting line release mechanism. Shooting line (90) ties the shaft (60) to the body (10).

In order to load the speargun, the user attaches the shaft cord notch (62) to the shaft cord

(71) which is stretched between the horizontal rollers (80). Then the shaft is pushed backwards inside the enclosed shaft guide (50) until it clicks into the trigger mechanism (30). Front ends of the rubber band (70) moves forward simultaneously until they reach the rear surface of the head part. After the shaft (60) is positioned, the user rigs the shooting line (90) to stay orderly in the shooting line cavity (11). Figure 9 Section B shows the cross section of the body without rigging and Section A after the rigging. Note that in Section A, cross sections of the shooting line (90) are seen in the shooting line cavity (11). Then the rubber bands (70) are stretched with leg power by pressing on the rear surface of the head part (40) which serves as a step. The loading process is completed with the attachment of the single circular band (70)(or the wishbone cord (72) if "dual rubber bands (70)" configuration is preferred) to the rear end of the speargun body (10).

When the user pulls the trigger (31), the shaft (60) is released from the trigger mechanism (30) and projectiles forward by the shaft cords as seen in the figure 10. The shooting line is released simultaneously as well. Once the rubbers (70) return to their original lenght, the shaft cord (71) stretches out between the two horizontal rollers (80) to prepare the speargun for the next shot.

Claims

1. The invention is a rubber band{70) powered speargun which provides easier handling on the horizontal plane in water, has less recoil, can be loaded with leg power, used for hunting underwater, with:

• at least one shaft cord (71) continuous with the front ends of the rubber bands (70) when the speargun is loaded,

• horizontal rollers (80) which inverts the direction of the force by rubber bands (70) during the shot,

• a speargun body (10) which includes a spear line cavity (11) which is an empty housing along the shaft's(60) upper surface.

2. Horizontal rollers (80) that are related to claim 1, characterized by the shaft cord(71) rotating around them to invert directions.

3. The invention is a rubber band(70) powered speargun which provides easier handling on the horizontal plane in water, has less recoil, can be loaded with leg power, used for hunting underwater, with a shaft cord notch (62) in the midline of the rear end of the mentioned shaft (60) where the mentioned shaft cord (71) is attached.