Hand operated hoist

Abstract

 A hoist (10) for moving a load (70) comprises an attachment body (40), a first handle (20) and a second handle (30), each handle (20, 30) being connected to the attachment body (40) with a respective line (50). The hoist (10) further comprises a locking/releasing mechanism (90) for fixing and altering, consecutively, a distance (100) between each handle (20, 30) and the attachment body (40). Reciprocating movements of the two handles (20, 30) can be turned into a linear movement of the load (70) by fixing and altering, consecutively, a distance (100) between each handle (20, 30) and the attachment body (40).

Description

TECHNICAL FIELD

[0001] The present invention relates to a hand operated hoist and to a related method for moving a load with muscle power.

BACKGROUND ART

[0002] Lifting or dragging of loads light enough to be moved with muscle power often happens with help of a line: a rope, a cable, a chain, a strap, or the like. A simple method of moving a load with a rope involves binding the rope to the load and pulling the rope to a desired direction. A drawback of this method is that the operator either has to move to the desired direction himself, or he has to constantly change the grip on the rope in order to pull the load towards himself. Another drawback is that the rope is difficult to grip solidly, and a great risk of dropping a hanging load exists. Much of the muscle power is needed for gripping the rope, and less power remains for the movement itself. The situation is especially risky when the load is the operator himself, and losing the grip amounts to the operator falling down and eventually injuring himself.

[0003] Hoists may be operated manually or with help of a machine. Hand operated hoists are known from e.g. US3516642 and US2003085392. These devices are based on a capstan, ratchet and a hand lever, and are meant for relatively heavy loads that are difficult or impossible to move with direct muscle power. The drawback of these devices is that in use they have to be attached to a stationary fixing point. Another drawback is that they are slow and uncomfortable to use for loads that are light enough to be moved with direct muscle power. The same drawbacks apply to the device of US2497805 featuring two reciprocating hooks.

[0004] Jacks and elevators are known, e.g. from GB1072479, where the load is raised and lowered step-by-step, and wherein the load rests between the movement steps on pawls or the like. The drawback of these devices is that they are slow because of a break between the raising/lowering steps, during which the reciprocating actuator is returned to its initial position.

[0005] There remains a desire to provide a hoist which is operated with direct muscle power but which overcomes the drawbacks of a simple rope.

SUMMARY OF THE INVENTION

[0006] One object of the invention is to provide an improved hand operated hoist which can be operated fast without changing the grip. Another object of the invention is to provide an improved method for moving a load.

[0007] These objects are achieved by the device according to the appended claim 1 and the method according to the appended claim 14.

[0008] The invention is based on the realization that reciprocating movements of two handles can be turned into a linear movement of a load by fixing and altering, consecutively, a distance between each handle and an attachment body to which the load is attached.

[0009] According to a first aspect of the invention, there is provided a hoist comprising an attachment body, a first handle and a second handle, each handle being connected to the attachment body with a respective line. The hoist further comprises a locking/releasing mechanism for fixing and altering, consecutively, a distance between each handle and the attachment body. With such a hoist reciprocating movements of the operator's hands can be turned into a linear movement of a load without a need for the operator to change grip.

[0010] According to one embodiment of the invention, the hoist further comprises a retraction mechanism for retracting the lines within the attachment body or within each handle. When the lines are preserved within a housing they are well protected and are not disturbing the operator by hanging loose.

[0011] According to one embodiment of the invention, each handle comprises an actuator for changing the state of the locking/releasing mechanism. By this measure the consecutive operation of each handle becomes easy and logical.

[0012] According to one embodiment of the invention, altering the distances between both handles and the attachment body simultaneously is prevented when the hoist is exposed to a load. By this measure dropping of a hanging load is prohibited.

[0013] According to one embodiment of the invention, each handle comprises a reel around which the respective line is spooled. Around a reel the line is preserved compactly and it is easily made retractable.

[0014] According to one embodiment of the invention, the attachment body comprises a reel around which a line is spooled. Around a reel the line is preserved compactly and it is easily made retractable. The handles can be smaller in size when at least part of the line is spooled within the attachment body.

[0015] According to one embodiment of the invention, the locking/releasing mechanism comprises a remote control. This provision makes it possible to integrate the locking/releasing mechanism within the attachment body which is remote from the operator in use.

[0016] According to one embodiment of the invention, the remote control comprises a wireless communication link between each handle and the attachment body. This is a convenient way to realize the remote control.

[0017] According to one embodiment of the invention, the reel comprises a motor spring or an electrical motor for spooling the line. These are convenient ways to realize the retraction function.

[0018] According to one embodiment of the invention, the reel comprises an inertia lock. An inertia loch further improves safety of the hoist by preventing fast extraction of the line.

[0019] According to one embodiment of the invention, the hoist further comprises a harness and a harness fastener for attaching each handle to the harness. A harness fastened to both handles further improves safety of the hoist by preventing falling of an operator when losing a grip.

[0020] According to one embodiment of the invention, the hoist further comprises a foot loop for allowing an operator to use leg muscles for lifting up himself. Using leg muscles significantly facilitates climbing.

[0021] According to one embodiment of the invention, the line is a rope, a cable, a chain or a strap. These are preferable and easily retractable forms of lines among other options.

[0022] According to a second aspect of the invention, there is provided a method for moving a load. The method comprising the steps of providing an attachment body; providing a first handle and a second handle; fixing a distance between the first handle and the attachment body while shortening or lengthening a distance between the second handle and the attachment body; fixing the distance between the second handle and the attachment body while shortening or lengthening the distance between the first handle and the attachment body; and repeating the two previous steps such that a linear movement of the load in a desired direction is achieved. With such a method reciprocating movements of the operator's hands can be turned into a linear movement of the load without a need for the operator to change grip.

[0023] According to one embodiment of the invention, the method further comprises the steps of fixing the attachment body to a stationary position; and repeating the above steps to achieve a lifting or lowering movement of an operator. By this measure the operator can use the method to lift up himself.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will be explained in greater detail with reference to the accompanying drawings, wherein

figure 1

shows a hoist according to one embodiment of the present invention,

figure 2

shows a hoist according to one embodiment of the present invention,

figure 3

shows a handle according to one embodiment of the invention,

figure 4

shows an exploded view of the handle of figure 3,

figure 5a

shows a ratchet within the handle of figure 3 in a first operation state,

figure 5b

shows a release mechanism within the handle of figure 3 in the first operation state,

figure 6

shows a ratchet of figure 5a and a release mechanism of figure 5b in a second operation state,

figure 7

shows a ratchet of figure 5a and a release mechanism of figure 5b in a third operation state, and

figure 8

shows an application where an operator uses a hoist according to one embodiment of the invention to lift up himself.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0025] With reference to figure 1, a hoist 10 according to one embodiment of the invention comprises a first handle 20 and a second handle 30, the two handles 20, 30 being identical. Each of the handles 20, 30 is connected to an attachment body 40 with a line 50 in the form of a stiff rod whose cross-section is flat in a first direction and comprises circular elements 60 in a direction perpendicular to the first direction. A load 70 is hanging from the attachment body 40. Together with rectangular openings 80 in the attachment body 40 the circular elements 60 form a locking/releasing mechanism 90 for fixing a distance 100 between one of the handles 20, 30 and the attachment body 40, and for allowing the distance 100 between the other handle 20, 30 and the attachment body 40 to change. The status (locked or released) of the locking/releasing mechanism 90 is changed by a turning movement of the respective handle 20, 30 illustrated by circular arrows 110 about the longitudinal axes of the respective rods.

[0026] In figure 1 the distance 100 between the first handle 20 and the attachment body 40 is fixed since the respective rod is turned into a position where the respective circular element 60 does not fit inside the respective opening 80. The distance 100 between the second handle 30 and the attachment body 40 is not fixed since the respective rod is turned into a position where the circular elements 60 pass freely through the respective opening 80. The first handle 20 may in the first instance be used to raise or lower the load 70, while the second handle 30 may be moved to an opposite direction to prepare for a next instance of raising or lowering, illustrated by the respective linear arrows 120. In the next instance, the second handle 30 is turned 90 degrees to fix the distance 100 between it and the attachment body 40, and the first handle 20 is likewise turned 90 degrees to allow the distance 100 between it and the attachment body 40 to change. By repeating the previous steps according to a simple logic an operator 350 (see figure 8) achieves a linear movement of the load 70 in a desired direction.

[0027] With reference to figure 2, a hoist 10 according to one embodiment of the invention comprises two identical handles 20, 30. Each of the handles 20, 30 comprises a reel 130 around which a respective line 50 in the form of a strap is spooled. The reel 130 comprises a ratchet gear 140 which interacts with a push-button 150 to lock and release, respectively, the distance 100 between the respective handle 20, 30 and the attachment body 40. The reel 130 also comprises a motor spring 210 (see figure 4) for retracting the strap 50 by automatically spooling it around the reel 130 when the push-button is released and the strap 50 is loose. This kind of construction with a retracting line 50 is known from dog leashes, one of which is known from EP0093445. Furthermore, the reel 130 may comprise an inertia lock (or a centrifugal clutch), which makes that the line 50 can be locked with a slight wrench. A mechanism with a motor spring and an inertia lock is known from vehicle seat belts, one of which is known from GB2170094, and also from retractable lifelines known e.g. from US20070151805 and US5186289. A person skilled in the art can find several ways of providing the respective locking/releasing mechanism 90 using e.g. ratchet gears in combination with pawls, these mechanisms also being known from dog leashes. As a difference to typical dog leashes it is preferable to provide a locking/releasing mechanism 90 which is locked when not actuated by the operator 350, and released when actuated.

[0028] Figure 3 shows a handle 20, 30 comprising a strap 50 spooled around a reel 130. The reel 130 is positioned between a right housing 160 and a left housing 170, and is rotatable about a shaft 180 which in its turn is stationary in relation to the housings 160, 170. The handle 20, 30 according to the shown embodiment of the invention has three operation states depending on the position of a push-button 150 used as an actuator to change the status of a locking/releasing mechanism 90 (see figure 5a). The function of the locking/releasing mechanism 90 will be explained in more detail hereinafter. In figure 3 the push-button 150 is biased to its upmost position by a compression spring 190. In use the operator 350 holds a grip 200 of a respective handle 20, 30 in each hand, and operates the respective push-button 150 with the respective thumb. The strap 50 of each handle 20, 30 is connected to an attachment body 40 which in its turn is attached to a load 70. For each handle 20, 30 the operator 350 is able to lock and release the reel 130 by operating the push-button 150, and a linear movement of the load 70 can be achieved from consecutive reciprocating movements of the two handles 20, 30.

[0029] Figure 4 shows an exploded view of the handle 20, 30 of figure 3. The innermost end of a motor spring 210 is inserted into a slot 220 in the shaft 180 in order to prevent a rotation of that end. The outermost end of the motor spring 210 is inserted into a cut 230 in a reel periphery. Consequently, the motor spring 210 is tightened when the strap 50 is extracted, and relaxed when the strap 50 is retracted. The motor spring 210 is constantly biased to retract the strap 50, but since the torque of the motor spring 210 is very limited, the retraction can only occur when the strap 50 is substantially loose. Figure 4 further shows two pawls 240 rotatable about pawl pins 250 and biased by torsion springs 260 to engage an internal gear 270 (see figure 5a) integrated into the reel 130. Together the pawls 240 and the internal gear 270 constitute a locking mechanism in the form of a ratchet whose main function is to prevent the strap 50 from extracting but which in this particular embodiment also prevents the strap 50 from retracting when the push-button 150 is not actuated, as will be explained later.

[0030] With reference to figure 5, in a first operation state of the handle 20, 30 the locking/releasing mechanism 90 is not actuated. It is obvious from figure 5a that in this operation state the ratchet prevents the extraction of the strap 50. Figure 5b shows a bar 280 in a sliding relation with a groove 290 in the right housing 160, the bar 280 comprising two cam pins 300 constituting kinematic pairs with respective follower surfaces 310 at the pawls 240. In the first operation state of figure 5b the cam pins 300 are not in contact with the follower surfaces 310, and the pawls 240 are biased to engage the internal gear 270. However, the lower pawl 240 has, in contrast with the upper pawl 240, a small projection 320 next to the respective follower surface 310. The projection 320 may come into a contact with the respective cam pin 300 and prevent any attempt to retract the strap 50. The projection 320 thus makes that the strap 50 is kept in its extracted position when the handle 20, 30 is in the first operation state, which may be an advantage in certain applications of the hoist 10. The projection 320 is optional and may not be desired in all embodiments of the invention.

[0031] With reference to figure 6, in a second operation state of the handle 20, 30 the locking/releasing mechanism 90 does not restrict the rotation of the reel 130. In this state the rotation of the reel 130 depends solely on the forces applied on it on one hand by the motor spring 210 attempting to retract the strap 50 (the handle 20, 30 is moved towards the attachment body 40), and on the other hand by the operator's 350 eventual muscle power attempting to extract the strap 50 (the handle 20, 30 is moved away from the attachment body 40). The follower surfaces 310 at the pawls 240 comprise notches 330 receiving the respective cam pins 300 at the second operation state. The interaction between the notches 330 and the cam pins 300 gives the operator 350 a feedback in the form of a changing pushing force of the push-button 150 signalling that the handle 20, 30 is in the second operation state. When switching from the first operation state to the second operation state, the reel 130 needs to rotate slightly in the retracting direction to allow the tips of the pawls 240 to pass by the respective gear teeth 340. This rotation happens easily when the strap 50 is loose or lightly loaded. However, when the strap 50 is heavily loaded, it becomes impossible to switch from the first operation state to the second operation state. Consequently, when handling a (heavy) hanging load 70 with a hoist 10 according to the described embodiment, only one of the straps 50, the loose one, can be extracted or retracted at a time.

[0032] With reference to figure 7, in a third operation state of the handle 20, 30 the ratchet again prevents the extraction of the strap 50. With the shown embodiment of the handle 20, 30 comprising the projection 320, the third operation state differs from the first operation state in that retraction of the strap 50 is not prevented in the third operation state. The torque of the motor spring 210 is sufficient for causing the pawls 240 to turn against the biasing force from the respective torsion springs 260, and for retracting a loose strap 50. As a consequence, with consecutive reciprocating movements of two handles 20, 30 kept in the third operation state, the attachment body 40 can be pulled towards the operator 350 without the need for the operator 350 to change operation state of any of the two handles 20, 30. In an embodiment without the projection 320 the operation of the handle 20, 30 in the first operation states is identical with that in the third operation state.

[0033] With reference to figure 8, a load 70 does not necessarily need to be directly attached to the attachment body 40. According to the shown application and embodiment of the hoist 10 the attachment body 40 is attached to a stationary fixing point and the operator 350 uses the device for lifting up himself i.e. the operator 350 constitutes the load 70. Instead of being integrated within the handles 20, 30, the two reels 130 are integrated within the attachment body 40. There is an electric motor 360 connected to each reel 130 to retract a respective strap 50. In the shown case an operator 350 uses the hoist 10 to lift up himself. The electric motors 360 are not powerful enough to retract a strap 50 loaded with the weight of the operator 350, but they are able retract a loose strap 50. The operator 350 therefore needs to use muscle power for lifting up himself. The reels 130 comprise a ratchet (not shown) corresponding to that disclosed in figures 5 to 7, but with locking and releasing of the ratchet being controlled from a remote distance. There is a wireless communication link 370 between each handle 20, 30 and the attachment body 40, each handle 20, 30 comprising a radio transmitter 380 and a push-button 150 for sending operation state information, and the attachment body 40 comprising a radio receiver 390. The operator 350 controls the remote controlled ratchets with his thumbs.

[0034] The handles 20, 30 further comprise carabiner holes 400 for receiving carabiners 410 of harness fasteners 420. The operator 350 wears a harness 430 which is connected to each handle 20, 30 with a harness fastener 420 and which prevents the operator 350 from falling even if he would lose grip of the handles 20, 30. Moreover, a foot loop 440 is attached to each handle 20, 30 to allow the operator 350 to use leg muscles for lifting up himself.

[0035] The present invention has a wide range of applications. The hoist 10 may be used e.g. for lifting water from a well, lifting building material at a building construction, saving people through a window from the roof of a burning house, helping a fishing mate, such as Sami or Kekke, back on the boat, etc. When the attachment body 40 is fixed to a stationary fixing point the hoist 10 may be used e.g. in mountain climbing and in training muscle power by climbing up and down. The hoist 10 is also a practical tool when climbing in a mast of a sailing boat. A sailor can extract the lines 50 of the hoist 10, lift the attachment body 40 up in the mast by using a sail rope, and operate the handles 20, 30 to climb up in the mast in a safe way.

[0036] The invention is not limited to the embodiments shown above, but the person skilled in the art may modify them in a plurality of ways within the scope of the invention as defined by the claims.

Claims

1. A hoist (10) comprising:

- an attachment body (40), and

- a first handle (20) and a second handle (30), each handle (20, 30) being connected to the attachment body (40) with a respective line (50),
characterized in that the hoist (10) further comprises a locking/releasing mechanism (90) for fixing and altering, consecutively, a distance (100) between each handle (20, 30) and the attachment body (40).

2. A hoist (10) according to claim 1, wherein the hoist (10) further comprises a retraction mechanism for retracting the lines (50) within the attachment body (40) or within each handle (20, 30).

3. A hoist (10) according to any of the preceding claims, wherein each handle (20, 30) comprises an actuator (150) for changing the status of the locking/releasing mechanism (90).

4. A hoist (10) according to any of the preceding claims, wherein altering the distances (100) between both handles (20, 30) and the attachment body (40) simultaneously is prevented when the hoist (10) is exposed to a load (70).

5. A hoist (10) according to any of the preceding claims, wherein each handle (20, 30) comprises a reel (130) around which the respective line (50) is spooled.

6. A hoist (10) according to any of the preceding claims, wherein the attachment body (40) comprises a reel (130) around which a line (50) is spooled.

7. A hoist (10) according to claim 6, wherein the locking/releasing mechanism (90) comprises a remote control.

8. A hoist (10) according to claim 7, wherein the remote control comprises a wireless communication link (370) between each handle (20, 30) and the attachment body (40).

9. A hoist (10) according to any of claims 5 to 8, wherein the reel (130) comprises a motor spring (210) or an electric motor (360) for spooling the line (50).

10. A hoist (10) according to any of claims 5 to 9, wherein the reel (130) comprises an inertia lock.

11. A hoist (10) according to any of the preceding claims, wherein the hoist (10) further comprises a harness (430) and a harness fastener (420) for attaching each handle (20, 30) to the harness (430).

12. A hoist (10) according to any of the preceding claims, wherein the hoist (10) further comprises a foot loop (440) for allowing an operator (350) to use leg muscles for lifting up himself.

13. A hoist (10) according to any of the preceding claims, wherein the line (50) is a rope, a cable, a chain or a strap.

14. A method for moving a load (70), the method comprising the steps of:

- providing an attachment body (40); and

- providing a first handle (20) and a second handle (30);
the method being characterized by the steps of:

- fixing a distance (100) between the first handle (20) and the attachment body (40) while shortening or lengthening a distance (100) between the second handle (30) and the attachment body (40);

- fixing the distance (100) between the second handle (30) and the attachment body (40) while shortening or lengthening the distance (100) between the first handle (20) and the attachment body (40); and

- repeating the two previous steps such that a linear movement of the load (70) in a desired direction is achieved.

15. The method according to claim 14, the method further comprising the steps of:

- fixing the attachment body (40) to a stationary position; and

- repeating the steps of claim 14 to achieve a lifting or lowering movement of an operator (350).

Drawing