Hand lifting device

Abstract

comprising hand lifting device (15): - a first drive wheel (33) with two spaced-apart first side plates (37) and a first circumferential surface (38) arranged between them, which has a first diameter (d1), wherein the first side plates (37) project radially beyond the first circumferential surface (38), so that a first receiving space (39) for receiving a longitudinal section of a drive pull element (35) is provided between the first side plates (37) and adjacent to the first circumferential surface (38), - a second drive wheel (34) arranged next to the first drive wheel (33) with two spaced-apart second side plates (45) and a second circumferential surface (46) arranged between them, the second circumferential surface having a second diameter (d2) smaller than the first diameter (d1), wherein the second side plates (45) project radially beyond the second circumferential surface (46), so that a second receiving space (47) for receiving the longitudinal section of the drive cable element (35) is provided between the second side plates (45) and adjacent to the second circumferential surface (46), wherein the first side plate (37) of the first drive wheel (33) immediately adjacent to the second drive wheel (34) has a circumferential recess (48) which is configured to guide the drive cable element (35) out of the first receiving space (39) into the second receiving space (47) or out of the second receiving space (47) into the first receiving space (39), - a drive shaft (31) which is non-rotatably connected to the first drive wheel (33) and the second drive wheel (34), and which is drive-coupled to a load wheel (18) which is rotatable about a pivot axis (D), - wherein the drive shaft (31) is coupled to the load wheel (18) via a self-locking transmission (32), - wherein the transmission (32) is designed as a worm gear (55) and has a worm (57) which is non-rotatably connected to the drive shaft (31) and which engages with one or two worm wheels (60), each worm wheel (60) being non-rotatably coupled to the load wheel (18), - wherein the transmission (32) is designed as a bevel gear (56), wherein each worm gear (60) is designed as a crown gear (62), - wherein each worm wheel (60) is deflectable or movable parallel to the axis of rotation (D) and has a friction surface (70) on the rear side (69) facing away from the worm (57), which faces a braking surface (71) arranged on a housing (16) of the hand lifting device (15), - wherein the transmission (32) is arranged such that a gap (73) exists between each friction surface (70) and the associated braking surface as long as a load torque (ML) on the load wheel (18) is less than a predetermined torque threshold value, and that each friction surface (70) is in contact with the associated braking surface (11) when the load torque (ML) on the load wheel (18) is at least as large as the predetermined torque threshold value, and that when the load torque (ML) reaches the predetermined torque threshold value, a sliding movement takes place between a toothing (59) of the worm wheel (60) and a toothing of the worm (57) in the engagement area (61), whereby the worm wheel (60) is deflected away from the worm (57) in the axial direction (A), thereby closing the gap (73) between the friction surface (70) and the associated braking surface (71) and the friction surface (70) against the associated braking surface (71) is pressed.

Description

[0001] The invention relates to a manual hoist with a drive wheel that can be rotated manually, in particular by means of a drive element, such as a drive chain, a drive belt, a drive cable, or the like. The rotation of the drive wheel is converted into a rotation of a motion-coupled or drive-coupled load wheel in order to raise or lower a load by means of a load element, such as a load chain, a load cable, or a load belt.

[0002] Such manual hoists are known. For example, DE 12 56 859 A describes a manual hoist that can be operated using a ratchet or ratchet. To ensure the manual hoist is kickback-free, a load pressure brake is provided. The load pressure brake has a brake nut whose internal thread engages an external thread of a drive shaft. The brake nut is driven when the ratchet is moved, as long as the torque does not exceed a set threshold. The torque is transmitted via the threaded connection between the brake nut and the drive shaft. When the ratchet is stationary, the load on the drive shaft tends to rotate it back in the opposite direction. During such a rotation, the brake nut moves axially on the drive shaft and presses the friction linings of the load pressure brake against each other. This prevents uncontrolled movement of a load.

[0003] DE 12 00 500 A discloses a hoist with a drive shaft that can be driven manually or by an electric motor. The load pressure brake present therein is designed as a drum brake. Expandable brake shoes have a friction lining that is coaxially enclosed by a brake drum. Disc spring assemblies are located between the brake shoes, which spread the brake shoes and, by pressing against the brake drum, create a braking effect when the drive shaft on the drive side is not subjected to any torque. This holds a load. As soon as a torque is applied to the drive shaft on the drive side, the angled disc spring assemblies are aligned and the braking effect is released.

[0004] WO 2019 / 045299 A1 discloses a manual hoist with two drive wheels. The peripheral surface of each drive wheel is recessed in a groove-like manner. This creates a receiving space for a longitudinal section of a drive pull element (chain). The two drive wheels have different diameters and are arranged directly adjacent to one another on a common shaft ( Fig. 12-22).

[0005] DE 11 2006 000 681 B4 discloses a lifting device with a device for preventing overloading. The lifting device has a load pulley on which a load chain is arranged. The load pulley can be coupled to an actuating means that can be operated by means of a hand chain. To lift a load, the actuating means can apply a torque to a rotary drive element that engages with a drive element via a toothing. The drive element, in turn, is rotatably coupled to the load wheel. A spring holds toothed projections of the rotary drive element in engagement with toothed recesses of the drive element. In the event of an overload, the toothed projections of the rotary drive element disengage from the respective associated toothed recess of the drive element, thus enabling relative rotation until the toothed projections engage with the respective next toothed recess in the direction of rotation.This essentially causes the coupling between the rotary drive element and the drive element to slip. This limits the maximum torque that can be transmitted between the rotary drive element and the drive element, and thus between the actuating means and the load wheel.

[0006] US 1,483,758 A describes another manual hoist based on the principle of a differential pulley block with differently sized sprockets. Using a coupling device, the two sprockets can be connected to each other in a rotationally fixed manner, or one of the two sprockets can be blocked against rotation, so that only one of the two sprockets is used.

[0007] Manual hoists are often large and bulky. This is due to the fact that the design must prevent the maximum manual force that can be applied from being exceeded. The applicable safety regulations also have a high safety factor that must be taken into account. In order to limit the manual force and still be able to lift the load, a high gear ratio is required, which can be up to 100 (for a nominal load of 3 tonnes). The effort required to turn the drive wheel, for example via a tension element, is therefore enormous. If a drive tension element is used for drive, with a gear ratio of 100, for example, 300 meters of the drive tension element would have to be moved over the drive wheel to achieve a lifting height of 3 meters. Especially with manual operation, this is time-consuming and quickly tires the operator.

[0008] To limit the manual force, load limiters are sometimes installed, which cause the drive wheel to slip when a certain load or torque is reached.

[0009] Based on this, the object of the invention can be considered to be to create an improved manual lifting device. In particular, it should be easier to operate and / or achieve a compact design.

[0010] This object is achieved by a manual lifting device having the features of patent claim 1.

[0011] According to a first aspect of the invention, a manual hoist comprises a first drive wheel and a second drive wheel arranged adjacent to it. The drive wheels are of different sizes and thus provide different gear ratios between the respective drive wheel and a load wheel coupled to the drive wheel, by whose rotation a load can be moved.

[0012] The first drive wheel has two first side walls arranged at a distance from one another. Between the two first side walls, the first drive wheel has a first circumferential surface extending in the circumferential direction. The circumferential surface and the two first side walls define a first receiving space for receiving a longitudinal section of a drive pull element with which the first or second drive wheel can be actuated or rotated. The drive pull element is preferably a drive chain. Alternatively, a drive belt or a drive cable could also be used as the pull element.

[0013] Similar to the first drive wheel, the second drive wheel has two second side walls and a second circumferential surface arranged therebetween, which extends in the circumferential direction. Adjacent to the second circumferential surface and between the second side walls, a second receiving space is provided for receiving the longitudinal section of the drive train element.

[0014] The first circumferential surface has a first diameter. The second circumferential surface has a second diameter. The first and second circumferential surfaces are each arranged concentrically around a common longitudinal axis, along which a drive shaft extends. Both drive wheels are connected to the drive shaft in a rotationally fixed manner. The drive shaft is also drive-coupled to the load wheel, in particular by means of a gear. The load wheel is mounted so as to be rotatable about a rotation axis. As it rotates, the load wheel can drive a load-pulling element guided over the load wheel, for example a load chain, a load belt, or a load rope, and thereby move a load, in particular raise or lower it.

[0015] In order to guide the drive train element for rotating one of the two drive wheels, either from one drive wheel or into the other, the first side wall of the first drive wheel, which is arranged directly adjacent to the smaller second drive wheel, has a circumferential recess. The circumferential recess extends in the circumferential direction in an angular range of, for example, at least 20 to 50 degrees. Preferably, the angular range is less than 60 to 70 degrees. In one embodiment, the angular range can be from 40 degrees to 50 degrees.

[0016] The circumferential recess allows the drive train element to be guided from the first receiving area into the second receiving area. With continued rotation of the two drive wheels, the drive train element can gradually be taken over by the second drive wheel and ultimately guided exclusively by the second drive wheel. Conversely, it is also possible to guide the drive train element guided by the second drive wheel out of the second receiving space and through the circumferential recess into the first receiving space. With continued rotation, the drive train element can gradually be taken over by the first drive wheel and ultimately guided exclusively by the first drive wheel.

[0017] This allows the gear ratio of the manual hoist to be changed quickly and easily. For example, the second drive wheel can be used to move very light loads or to perform movements without a load, since less of the drive pulley needs to be guided over the second drive wheel than over the first drive wheel to achieve the same load travel. When lifting or lowering larger loads, the first drive wheel is actuated or rotated via the drive pulley.

[0018] Preferably, the first circumferential surface is laterally exposed or accessible in the region of the circumferential recess. In the region of the circumferential recess, the first side cheek does not protrude radially beyond the first circumferential surface. A section of the drive train element resting on the first circumferential surface can thus be guided out through the circumferential recess without first being lifted in the first receiving space and guided over the first side cheek.

[0019] Preferably, means are arranged in the first receiving space and / or in the second receiving space to positively secure the drive train element so that relative movement between the drive train element and the respective first or second drive wheel is avoided. A drive chain is preferably used as the drive train element. In this embodiment, receiving pockets arranged side by side in the circumferential direction can be provided in the first receiving space and / or in the second receiving space, each for a horizontal chain link of the drive chain. In the case of a horizontal chain link, the chain link extends essentially in a plane that is aligned tangentially to the circumferential direction. The receiving pocket is delimited by radial flanks that secure the horizontal chain link against movement in the circumferential direction relative to the drive wheel. The specific design of the receiving pocket can vary.The receiving pocket does not have to be completely enclosed in the circumferential direction and / or perpendicular thereto in an axial direction, but can also be limited by separate radial projections.

[0020] It is advantageous if the receiving pockets in the first receiving space and / or in the second receiving space, which are arranged directly adjacent in the circumferential direction, are each connected to one another via a connecting recess. A stationary chain link of the drive chain can engage in the connecting recess. A stationary chain link extends essentially in a plane oriented perpendicular to the longitudinal axis of the drive shaft.

[0021] It is advantageous if the circumferential recess has a length in the circumferential direction that corresponds to at least the length of two chain links of the drive chain. The circumferential recess can have a circumferential length that corresponds to a maximum of four to five chain links of the drive chain.

[0022] It is advantageous if the drive coupling between the drive shaft and the load wheel is implemented by means of a gear with a self-locking effect. The self-locking effect of the gear allows movement to be transmitted from the drive shaft via the gear to the load wheel, while conversely preventing movement from the load wheel via the gear to the drive shaft. The self-locking effect can be achieved by a sufficiently low efficiency and / or high gear ratios and / or moments of inertia. For example, the gear can be designed as a worm gear or have a worm gear stage. In particular, the pitch angle of the worm thread is smaller than the effective angle of the friction cone.

[0023] It is also advantageous if the transmission is designed as a worm gear and has a worm that is non-rotatably connected to the drive shaft. The worm meshes with one or two worm gears. Each worm gear is non-rotatably connected to the load gear.

[0024] In one embodiment, each worm gear can be designed as a crown gear. This allows an angular gear to be formed. Preferably, the longitudinal axis of the drive shaft is aligned perpendicular to the rotational axis.

[0025] If two worm gears are present, the worm can be arranged between the two worm gears. Additionally or alternatively, the load gear can be arranged between the two worm gears.

[0026] Preferably, each worm gear is deflectable or movable parallel to the rotational axis. The deflection parallel to the rotational axis can be achieved by elastic deformation of the worm gear. Alternatively, each worm gear can be arranged in a rotationally fixed and axially displaceable manner, for example, on a load shaft or on one or more bolts or pins. For this purpose, a splined shaft connection or a polygonal shaft connection, or another shape of the connection point between the at least one worm gear and the load shaft or the pins or bolts that deviates from the circular contour, can be used.

[0027] The worm gear may have a friction surface on a rear side facing away from the worm, which is opposite a braking surface. The braking surface is preferably arranged on a housing of the manual hoist. -9

[0028] As long as the load torque acting on the load wheel is less than a predetermined torque threshold, there is preferably a gap between the braking surface and the friction surface; however, at least no frictional or braking torque is generated in the circumferential direction about the rotation axis, even when there is contact between the friction surface and the braking surface. However, if the load torque reaches the torque threshold or becomes greater than the torque threshold, the friction surface and the braking surface are pressed against each other, and rotation of the load wheel about the rotation axis is braked or blocked. In this way, the maximum permissible load on the load wheel can be prevented from being exceeded, thereby limiting the manual force required by an operator when turning the first or second drive wheel.

[0029] In particular, a load-pulling element, for example a load chain, a load belt, or a load rope, is guided over the load wheel. Means are preferably arranged on the circumferential surface of the load wheel to positively secure the load-pulling element, thus preventing relative movement between the load-pulling element and the load wheel. A load chain is preferably used as the load-pulling element. The load wheel can be configured for use with a load chain and can have receiving pockets arranged side by side in the circumferential direction around the rotation axis, each for a horizontal chain link of the load chain.

[0030] In a preferred embodiment, exactly three storage pockets are provided. The load wheel can thus be designed very small and compact.

[0031] The manual hoist is preferably designed for load chain tensions of 200 MPa to 300 MPa, and in particular 50 MPa. The radius at which the load chain rolls off the second load wheel can be, for example, between 10 mm and 30 mm. This radius depends in particular on the wire diameter and the number of support pockets.

[0032] The first diameter of the first drive wheel is preferably 2-4 times the second diameter of the second drive wheel. The diameters of the drive wheels indicate the respective diameter of the circular path along which the drive train element extends when guided over the respective drive wheel.

[0033] A further aspect of the invention relates to the design of the load brake, as already mentioned above. This aspect can also be used regardless of whether one or two drive wheels are used. If only one drive wheel is present, the circumferential recess can be omitted, since then no transfer of the drive pull element from one drive wheel to the other is necessary.

[0034] The manual hoist according to the second aspect of the invention therefore has at least one drive wheel that is non-rotatably connected to a drive shaft. A worm gear designed as an angular gear establishes a drive connection between the drive shaft and a load wheel. The worm gear has a worm that is non-rotatably connected to the drive shaft and at least one worm gear designed as a crown gear that meshes with the worm. The at least one worm gear is non-rotatably connected to the load wheel. On a rear side facing away from the worm, the at least one worm gear has a friction surface. The friction surface faces a braking surface arranged on a housing of the manual hoist.

[0035] As already described above, no braking torque is generated between the friction surface and the braking surface as long as the load torque on the load wheel is less than a specified torque threshold. Preferably, a gap then remains between the friction surface and the braking surface. If the load torque reaches or exceeds the torque threshold, the friction surface is pressed against the braking surface and a braking torque is generated. The pressing of the friction surface against the braking surface is made possible by the fact that the teeth of the worm wheel can move at right angles to the longitudinal axis along the teeth of the worm at the point of engagement. If two worm wheels are present, the worm wheels are pushed outwards, deflected or displaced, away from each other. The braking effect blocks the load wheel and, ideally, prevents it from moving.

[0036] Advantageous embodiments of the invention will become apparent from the dependent claims, the description, and the drawings. Preferred embodiments of the invention are explained in detail below with reference to the accompanying drawings. They show: Fig. 1 a schematic diagram of an embodiment of a hand hoist with a view in the direction of a rotation axis about which a load wheel of the hand hoist is rotatably arranged. Fig. 2 another schematic diagram of the manual lifting device from Fig. 1 in a view perpendicular to the axis of rotation, Fig. 3 two drive wheels, a drive shaft and a worm gear of the manual hoist according to the Fig. 1 and Fig. 2 in a schematic side view, Fig. 4 a worm gear of the manual hoist designed as a crown gear according to the Fig. 1 and Fig. 2 in a schematic side view, Fig. 5 a cross section through a tooth of the worm gear from Fig. 4 according to section line VV, Fig. 6 a schematic diagram of the meshing between the teeth of the worm and the teeth of the worm wheel as long as a load torque is smaller than a torque threshold value, Fig. 7 a schematic diagram of the meshing of the worm and the worm wheel when the load torque on the load wheel is at least as large as a specified torque threshold value, Fig. 8 is a perspective view of an embodiment of a load wheel adapted for use with a load chain, Fig. 9 the load wheel according to Fig. 8 in a sectional view perpendicular to the axis of rotation D and Fig. 10 and Fig. 11 each shows a schematic diagram for transferring a drive pull element from one drive wheel to the other drive wheel in the manual hoist according to Fig. 1 and Fig. 2.

[0037] In the Fig. 1 and Fig. Figure 2 schematically illustrates an embodiment of a manual lifting device 15 in the form of a block diagram. The manual lifting device 15 has a housing 16. The housing 16 can be arranged at a desired height in order to lift a load located below it. For this purpose, the housing 16 has, for example, a hook 17, by means of which the housing 16 of the manual lifting device 15 can be suspended at a suitable location. The hook 17 can be arranged movable and, in particular, rotatably on the housing 16.

[0038] For lifting a load, the manual hoist 15 has a drivable load wheel 18. The load wheel 18 is mounted for rotation about a rotation axis D. A direction that is parallel to the rotation axis D is referred to as the axial direction A. For rotatable mounting, the load wheel 18 can, for example, be arranged in a rotationally fixed manner on a load shaft 19. The load shaft 19 extends along the rotation axis D and is rotatably mounted in the housing 16. As shown by way of example in Fig. As illustrated in Figure 2, the load shaft 19 can be rotatably mounted at its two opposite ends via a pivot bearing 20 in the housing 16. The pivot bearings 20 are preferably designed as rolling bearings.

[0039] A load-pulling element 21, which is formed, for example, by a load chain 22, is guided over the load wheel 18. In order to prevent the load chain 22 from sliding or slipping over the load wheel 18, the load wheel 18 has receiving pockets 23 arranged side by side in the circumferential direction U about the rotation axis D, each for a horizontal chain link 24 of the load chain 22. The horizontal chain link 24 extends essentially in a plane that is aligned tangentially to the circumferential direction U. Two receiving pockets 23 of the load wheel 18 that are immediately adjacent in the circumferential direction U are connected via a connecting recess 25 in the load wheel 18, into which a vertical chain link 26 of the load chain 22 can engage. The chain links 24, 26 are therefore supported in the circumferential direction U against relative movement relative to the load wheel 18 and are held in a form-fitting manner. As shown in the Fig. 8 and Fig. As illustrated in Figure 9, a central radial projection 27 can protrude into each receiving pocket 23 of the load wheel 18. Each stationary chain link 26 is arranged between two radial projections 27 and supported in the circumferential direction U. The radial projections 27 thus delimit the connecting recess 25.

[0040] Each receiving pocket 23 is delimited in the circumferential direction U on both sides by two outer radial projections 28, which are arranged at a distance from one another in the axial direction A. A horizontal chain link 24 is supported on two outer radial projections 28 on both sides, viewed in the circumferential direction U.

[0041] As it is in the Fig. 8 and Fig. As can be seen in Figure 9, the receiving pockets 23 or the connecting recesses 25 do not have to be completely closed all the way around. It is sufficient if the chain links 24, 26 are sufficiently supported in the circumferential direction U to prevent slippage of the load chain 22. Other designs of the load wheel 18 are also possible to appropriately support the chain links 24, 26 in the circumferential direction U.

[0042] In the preferred embodiment, the load wheel 18 has exactly three receiving pockets 23 and thus also three connecting recesses 25. This allows the load wheel 18 to be constructed very small and compact and preferably has an effective radius of 10 mm to 30 mm and preferably about 24-25 mm, along which the horizontal chain links 24 move. The effective diameter dL of the load wheel 18 is in Fig. 9. It corresponds approximately to twice the distance between a center plane through a chain link 24 located in the receiving pocket 23 and the rotation axis D.

[0043] The load wheel 18 is drive-connected to a drive shaft 31 via a gear 32. The drive shaft 31 is non-rotatably connected to at least one drive wheel, for example, to a first drive wheel 33 and a second drive wheel 34. The gear 32 has a non-variable gear ratio that is greater than one, e.g., by at least one order of magnitude. The gear ratio between the first drive wheel 33 and the load wheel 18 is adjusted via the gear 32 such that, with the maximum permissible load that can be lifted, the manual force or drive torque on the first drive wheel 33 is not exceeded.

[0044] According to a first aspect of the invention, two drive wheels 33, 34 are provided, which can be driven by means of a drive train element 35 and rotated about a longitudinal axis L. The two drive wheels 33, 34 are arranged directly adjacent to one another. For example, the first drive wheel 33 is arranged between the housing 16 and the second drive wheel 34. The two drive wheels 33, 34 are connected to one another in a rotationally fixed manner and, in the exemplary embodiment, are seated in a rotationally fixed manner on the common drive shaft 31, which extends along the longitudinal axis L. A direction parallel to the longitudinal axis L is referred to as the longitudinal direction R. The longitudinal direction R is oriented at right angles to the axial direction A, so that the longitudinal axis L and the axis of rotation D are also oriented at right angles to one another.

[0045] Rotation of the drive wheels 33, 34 is converted via the gear 32 into a rotational movement of the load wheel 18 to lift a load. The drive wheels 33, 34 are rotated by the drive pulley 35. The drive pulley 35 is preferably a drive chain 36. Instead of a drive chain 36, other drive pulley elements 35, such as a drive belt or a drive cable, could also be used.

[0046] The first drive wheel 33 has two disc-shaped or annular first side cheeks 37, which are arranged at a distance from one another in the longitudinal direction R. Between the two first side cheeks 37, the first drive wheel 33 has a first circumferential surface 38. The first side cheeks 37 protrude radially to the longitudinal axis L beyond the first circumferential surface 38, so that a first receiving space 39 for a section of the drive chain 36 is formed adjacent to the first circumferential surface 38 and between the first side cheeks 37.

[0047] In the first receiving space 39, for example, means are provided for securing the drive chain 36 against relative movement relative to the first drive wheel 33. For this purpose, in the exemplary embodiment, receiving pockets 40 are arranged adjacently in the circumferential direction around the longitudinal axis L, each for a horizontal chain link 41 of the drive chain 36. A horizontal chain link 41 of the drive chain 36 extends in a plane that is oriented substantially tangentially to the circumferential direction around the longitudinal axis L. Two immediately adjacent receiving pockets 40 are connected to one another via a connecting recess 42 for a vertical chain link 43 of the drive chain 36. A vertical chain link 43 extends substantially in a plane that is oriented perpendicular to the longitudinal axis L.A section of the drive chain 36, which rests against the circumferential surface 38, has horizontal chain links 40 that engage in an associated receiving pocket 40 and has vertical chain links 43 that engage in an associated connecting recess 42. Through recesses or projections radial to the longitudinal axis L, which delimit the receiving pockets 40 or the connecting recesses 42, the chain links 41, 43 can be supported in the circumferential direction around the longitudinal axis L, thus preventing slippage of the drive chain 36.

[0048] The first circumferential surface 38 has a first diameter d1. This first diameter d1 is the effective diameter along which a section of the drive chain 36 moves when it rests against the first circumferential surface 38. The first diameter d1 can thus correspond to twice the distance of a center plane through a horizontal chain link 41 from the longitudinal axis L.

[0049] The second drive wheel 34 is designed analogously to the first drive wheel 33. It has disc-shaped or annular second side walls 45 arranged at a distance in the longitudinal direction R. Between the second side walls 45, the second drive wheel 34 has a second circumferential surface 46. Between the two second side walls 45 and the second circumferential surface 46, a second receiving space 47 for a section of the drive chain 36 is formed. Analogous to the first drive wheel 33, the second drive wheel 34 has receiving pockets 40 for horizontal chain links 41 arranged side by side in the circumferential direction around the longitudinal direction L, as well as connecting recesses 42 for vertical chain links 43.

[0050] The second circumferential surface 46 of the second drive wheel 34 has an effective second diameter d2 that is smaller than the first diameter d1. The effective second diameter d2 is, for example, twice the distance of a center plane through a horizontal chain link 41 arranged in a receiving pocket 40 from the longitudinal axis L.

[0051] The first diameter d1 can be a factor of 2-4 larger than the second diameter d2.

[0052] An operator can drive the manual hoist 15 by rotating the first drive wheel 33 or the second drive wheel 34. The drive chain 36 is guided over the respective drive wheel 33, 34, and pulling on the drive chain 36 causes a rotation about the longitudinal axis L, whereby this rotational movement is converted into a rotational movement of the load wheel 18 via the gear 32.

[0053] In the exemplary embodiment and according to a first aspect of the invention, both the first drive wheel 33 and the second drive wheel 34 are present. The first drive wheel 33 has a circumferential recess 48 in the first side wall 37, which is arranged directly adjacent to the second drive wheel 34. The circumferential recess is completely open radially to the outside in relation to the longitudinal axis. The circumferential recess penetrates the first side wall 37, and the first receiving space 39 is accessible from the side (in the longitudinal direction R). The circumferential recess 48 is in the Fig. 1 and Fig. 3 schematically illustrated and best seen in the Fig. 10 and Fig. 11 can be seen.

[0054] In the region of the circumferential recess 48, the first side cheek 37 preferably does not protrude radially beyond the first circumferential surface 38, or protrudes only slightly. As a result, the first receiving space 39 is laterally accessible in the longitudinal direction R. The circumferential recess 48 has a circumferential length in a circumferential direction around the longitudinal axis L that corresponds at least to the length of two or three interconnected chain links of the drive chain 36. The angular range along which the circumferential recess 48 extends in the first side cheek 37 can be, for example, 30 to 50 degrees.

[0055] As it is in the Fig. 10 and Fig. 11, the drive chain 36 can be shifted from the first receiving space 39 of the first drive wheel 33 into the second receiving space 47. During this process, the drive wheels 33, 34 are rotated about the longitudinal axis L, for example, counterclockwise, as shown in the Fig. 10 and Fig. 11 is shown by way of example. The drive chain 36 is guided out of the first receiving space 39 through the circumferential recess 48, for example, when the circumferential recess 48 is located approximately at the level of the longitudinal axis L or below. The section of the drive chain 36 guided out of the first receiving space 39 can then, with continued rotation, be introduced into the second receiving space 47 of the second drive wheel 34. Gradually, the length section of the drive chain 36 that is guided on the first drive wheel 33 decreases and the length section of the drive chain 36 that is guided on the second drive wheel 34 increases. After a rotation of at least 180 degrees about the longitudinal axis L, the drive chain 36 is then only guided over the second drive wheel 34.

[0056] According to the Fig. 10 and Fig. 11, the drive chain 6 can also be shifted from the second drive wheel 34 to the first drive wheel 33. For this purpose, the drive chain is guided through the circumferential recess 48 into the first receiving space 39 when the circumferential recess 48 is located below or at the level of the longitudinal axis L. If the drive wheels 33, 34 are then rotated further about the longitudinal axis, the length portion of the drive chain 36 that is guided over the first drive wheel 33 increases, while the length portion that is guided over the second drive wheel 34 decreases.

[0057] Due to the circumferential recess 48, it is possible to easily transfer the drive chain 36 from one drive wheel 33 or 34 to the other drive wheel 34 or 33.

[0058] The first drive wheel 33 with the larger first diameter d1 can be used for lifting larger loads. The second drive wheel 34 can be used, for example, when moving the load chain 22 with a light load. The smaller gear ratio from the second drive wheel 34 to the load wheel 18 compared to the gear ratio from the first drive wheel 33 to the load wheel 18 enables less fatigue when moving the load chain 22 without a load or with a light load. Nevertheless, the safe lifting or lowering of larger loads is ensured by using the first drive wheel 33.

[0059] In a second aspect of the invention, an overload protection device or a load pressure brake is provided via the gear 32. This second aspect can be used regardless of whether one or more drive wheels 33, 34 are present. If only one drive wheel is present, the circumferential recess 48 can be omitted.

[0060] The gear 32, which provides overload protection, has a self-locking effect in the exemplary embodiment. The transmission of a rotary motion from the drive shaft 31 to the load shaft 19 is permitted via the gear 32, while the transmission of a rotary motion from the load shaft 19 to the drive shaft 31 is prevented. To achieve this, the gear 32 in the exemplary embodiment is designed as a worm gear 55, which is preferably implemented in the form of an angular gear 56.

[0061] The worm gear 55 includes a worm 7, which is connected in a rotationally fixed manner to the drive shaft 31. 5 The worm 57 is arranged, together with the drive shaft 31, for rotation about the longitudinal axis L. The worm 57 has an external toothing with a tooth 58 extending in the shape of a helix around the longitudinal axis L. In the longitudinal direction R, the outer diameter of the tooth 58 decreases from the center of the worm 57 to both axial ends of the worm 57. This gives the worm 57 a convex and / or spherical outer contour. This facilitates the meshing of the tooth 58 of the worm 57 with a toothing 59 of a worm wheel 60 of the worm gear 55.

[0062] The worm gear 55 has at least one worm wheel 60, wherein in the exemplary embodiment, two preferably identically designed worm wheels 60 are provided. The worm wheels 60 are arranged at a distance from one another in the axial direction A and are connected in a rotationally fixed manner to the load shaft 19 ( Fig. 2). The worm gears 60 are in an engagement area 61 ( Fig. 1) engages with the worm 57. The engagement region 61 is arranged, for example, in the central region of the worm 57, viewed in the longitudinal direction R. There, the tooth 58 of the worm 57 engages the toothing 59 of the respective worm wheel.

[0063] As it is in the Fig. 1, Fig. 2 and Fig. 4, each worm wheel 60 is designed in the form of a crown wheel 62. The toothing 59 of each worm wheel 60 has teeth 63 arranged next to one another in the circumferential direction U around the rotational axis D along an annular surface. Between each two teeth 63 immediately adjacent in the circumferential direction U around the rotational axis D, a tooth gap 64 is formed ( Fig. 4). In the engagement region 61, at least one section of the tooth 58 of the worm 57 engages in an associated tooth gap 4 and preferably abuts both teeth 63 adjacent to the tooth gap 64. It is also possible for several sections of the tooth 58 to engage in several adjacent tooth gaps 64 in the engagement region 61.

[0064] In Fig. 5 is a schematic section through a tooth 63 of the worm gear 60 or the crown gear 62 along the section line VV in Fig. 4. It has a concave, circular-arc-shaped recess 65 on its head region associated with the worm 57. The radius of the circular-arc-shaped recess 65 can be adapted to the radius of the core of the worm 57, from which the helical tooth 58 of the worm 57 protrudes. In a sectional plane perpendicular to the circumferential direction U around the rotational axis D, a tooth 63 of the worm wheel 60 can have curved flanks and taper towards the tooth tip ( Fig. 6 and Fig. 7). Analogously, the tooth 58 of the worm 67 can have curved flanks in a section perpendicular to the longitudinal axis L and taper towards its tooth head ( Fig. 3, Fig. 6 and Fig. 7).

[0065] As is particularly evident from Fig. As can be seen from Figure 2, the worm 57 is arranged in the axial direction A between the worm gears 60. The longitudinal axis L preferably runs within a plane that is oriented at right angles to the axis of rotation D and passes through the center of the load wheel 18.

[0066] The worm gears 60, designed as crown gears 62, have a friction surface 70 on their respective rear side 69, which faces away from the worm 57. The friction surface 70 of each worm gear 60 faces a braking surface 71. The braking surface 71 is arranged on the housing 16. The braking surface 71 can be formed directly by a wall surface of the housing 16. Alternatively, a braking body having the braking surface 71 can be attached to the housing 16. It is also possible to arrange several braking bodies and / or braking surfaces 71 distributed in the circumferential direction U around the rotation axis D.

[0067] The worm gears 60 are deflectable and / or movable in the axial direction A. For example, the worm gears can be urged toward the worm 57 in the axial direction A by a preloading device 72 and can be displaced against the force of the preloading device in the event of an overload. For example, the preloading device can comprise disc spring assemblies that are supported directly or indirectly on the housing 16 on the one hand and on the worm gear 60 on the other. For example, the preloading device 72 can comprise two disc spring assemblies, each of which preloads one of the worm gears 60 toward the worm 57.

[0068] As an alternative to this embodiment, the worm gears 60 can be arranged immovably on the load shaft 19 in the axial direction A. They can be dimensioned such that, in the event of an overload, an elastic deformation occurs at the respective engagement area 61 and the worm gear 60 can be elastically deformed or deflected in the axial direction A.

[0069] For the rotationally fixed coupling and transmission of torque from the worm gears 60 to the load gear 18, one or more pins or bolts extending in the axial direction A can also be used, each connecting a worm gear 60 to the load gear 18. As described in connection with the arrangement of the worm gears 60 on the load shaft 19, the worm gears 60 can be mounted on the pins or bolts for axial displacement and preloaded toward the worm 57 by means of the preloading device 72. Additionally or alternatively, the worm gears 60 can be mounted axially immovably or non-displaceably and can be deflected in the axial direction A by elastic deformation in the event of an overload in order to generate a braking effect.

[0070] The manual hoist 15 is designed for specific loads or load torques ML around the rotation axis D, if the load exerts a tensile force F on the load chain 22 ( Fig. 2). If the load torque ML is less than a predetermined torque threshold value, which describes the maximum permissible load, no braking effect is achieved. The friction surface 70 of each worm gear 60 does not contact the associated braking surface 71, or only contacts it with a negligibly small force. Preferably, in the case of a permissible load or tensile force F, a gap 73 is present between each friction surface 70 and the associated at least one braking surface 71, as is exemplified in Fig. 2 is illustrated.

[0071] If the load torque ML reaches the torque threshold value, a sliding movement occurs between the toothing 59 of the worm gears 60 and the toothing or tooth 58 of the worm 57 in the respective engagement area 61, whereby the worm gears 60 are deflected away from the worm 57 in the axial direction A and displaced, for example, against the force of the pretensioning device 72. In this case, the intermediate space 73 is closed and the friction surfaces 70 are pressed against the respective associated at least one braking surface 71. A braking force is generated due to the friction pairing. Further rotation of the at least one drive gear 33 or 34 and the load gear 18 is braked and preferably blocked. This ensures that excessive loads are not lifted or lowered with the manual hoist 15.

[0072] The displacement of the gears in axial direction A is shown schematically in the Fig. 6 and Fig. 7. In Fig. Figure 6 illustrates the situation as long as the load torque ML is less than the specified torque threshold. In the engagement area 61, a section of the tooth 58 of the worm 57 engages in a tooth gap 64 between two teeth 63 of the worm wheel 60 and can, for example, also be in contact with both adjacent teeth 63. In the event of an excessive load, when the load torque ML is as great as or greater than the torque threshold, the worm wheel 60 is deflected or moved in the axial direction and, as a result, the section of the tooth 58 of the worm 57 engages less deeply in the tooth gap 64. In particular, depending on the direction of rotation, it is then only in contact with one of the teeth 63 of the worm wheel at a location that is closer to the respective tooth tips. The locations at which the teeth abut one another are shown in the Fig. 6 and Fig. 7 schematically outlined in dashed lines.

[0073] The flank steepness and / or contour of tooth 58 or teeth 63 is selected such that a displacement in the axial direction A can occur when the torque threshold is reached. The exact geometry of the tooth flanks can be determined experimentally or by simulation depending on additional parameters. As illustrated in the preferred embodiment described here, the two aspects of the invention can be combined. It is also possible to use the two aspects independently of one another.

[0074] The invention relates to a manual hoist 15 that can ensure simple and safe operation and a compact design. The manual hoist 15 has at least one drive wheel 33, 34, which is connected to a load wheel 18 via a gear 32. According to one aspect, two drive wheels 33, 34 are connected to one another in a rotationally fixed manner and can be rotated about a longitudinal axis L via a drive pull element 35, in particular a drive chain 36. Each drive wheel 33, 34 has a groove-shaped receiving space 39, 47. The groove-shaped receiving space 39 of the larger-diameter drive wheel 33 is open in a circumferential section through a circumferential recess 48 toward the smaller drive wheel 34. The drive pull element 35 can be guided through this circumferential recess 48, thereby enabling a shift from one drive wheel to the other drive wheel. Additionally or alternatively, the gear 32 can form a load pressure brake.In this embodiment, the gear 32 can preferably be designed as a worm gear 55 and / or angular gear 56. List of reference symbols 15 Manual hoist 16 housings 17 hooks 18 cargo bike 19 Load wave 20 pivot bearings 21 Towing element 22 Load chain 23 Cargo wheel pocket 24 lying chain link of the load chain 25 Connection recess of the load wheel 26 standing chain link of the load chain 27 central radial projection 28 outer radial projection 31 Drive shaft 32 gearboxes 33 first drive wheel 34 second drive wheel 35 Drive train element 36 drive chain 37 first side panel 38 first circumferential surface 39 first recording room 40 receiving pocket of the first or second drive wheel 41 lying chain link of the drive chain 42 Connecting recess of the first or second drive wheel 43 standing chain link of the drive chain 45 second side panel 46 second circumferential surface 47 second recording room 48 circumferential recess 55 worm gears 56 bevel gears 57 snail 58 Tooth of the snail 59 Worm gear teeth 60 Worm gear 61 Intervention area 62 Crown gear 63 tooth of the worm wheel 64 tooth gap 65 Deepening 69 Back 70 friction surface 71 braking surface 72 Pre-tensioning device 73 space A axial direction D axis of rotation d1 first diameter d2 second diameter d L effective diameter of the load wheel F traction force L Longitudinal axis ML load torque R Longitudinal direction

Claims

[1] Manual lifting device (15) comprising: - a first drive wheel (33) with two spaced first side cheeks (37) and a first circumferential surface (38) arranged therebetween, which has a first diameter (d1), wherein the first side cheeks (37) project radially beyond the first circumferential surface (38), so that between the first side cheeks (37) and adjacent to the first circumferential surface (38) a first receiving space (39) for receiving a longitudinal section of a drive train element (35) is arranged, - a second drive wheel (34) arranged next to the first drive wheel (33) with two spaced-apart second side walls (45) and a second circumferential surface (46) arranged therebetween, which has a second diameter (d2) smaller than the first diameter (d1), wherein the second side walls (45) project radially beyond the second circumferential surface (46), so that a second receiving space (47) for receiving the longitudinal section of the drive train element (35) is arranged between the second side walls (45) and adjacent to the second circumferential surface (46), wherein the first side wall (37) of the first drive wheel (33) immediately adjacent to the second drive wheel (34) has a circumferential recess (48) which is arranged to guide the drive train element (35) out of the first receiving space (39) into the second receiving space (47) or out of the second receiving space (47) into the first receiving space (39), - a drive shaft (31) which is connected in a rotationally fixed manner to the first drive wheel (33) and the second drive wheel (34) and which is drive-coupled to a load wheel (18) rotatable about a rotation axis (D), - wherein the drive shaft (31) is drive-coupled to the load wheel (18) via a gear (32) having a self-locking effect, - wherein the gear (32) is designed as a worm gear (55) and has a worm (57) which is connected in a rotationally fixed manner to the drive shaft (31) and which engages with one or two worm wheels (60), each worm wheel (60) being coupled in a rotationally fixed manner to the load wheel (18), - wherein the gear (32) is designed as an angular gear (56), wherein each worm gear (60) is designed as a crown gear (62), - wherein each worm wheel (60) is deflectable or movable parallel to the axis of rotation (D) and has a friction surface (70) on the rear side (69) facing away from the worm (57), which friction surface faces a braking surface (71) arranged on a housing (16) of the manual lifting device (15), - wherein the gear mechanism (32) is configured such that a gap (73) is present between each friction surface (70) and the associated braking surface as long as a load torque (ML) on the load wheel (18) is less than a predetermined torque threshold value, and that each friction surface (70) bears against the associated braking surface (11) when the load torque (ML) on the load wheel (18) is at least as great as the predetermined torque threshold value, and that when the load torque (ML) reaches the predetermined torque threshold value, a sliding movement takes place between a toothing (59) of the worm wheel (60) and a toothing of the worm (57) in the engagement region (61), as a result of which the worm wheel (60) is deflected in the axial direction (A) away from the worm (57), as a result of which the gap (73) between the friction surface (70) and the associated braking surface (71) is closed and the friction surface (70) is held against the associated braking surface (71) is pressed. [2] Hand hoist (15) according to claim 1, wherein the drive wheels (33, 34) are adapted for the use of a drive chain (36) as the drive traction element (35). [3] Manual lifting device (15) according to claim 2, wherein in the first receiving space (39) of the first drive wheel (33) and / or in the second receiving space (47) of the second drive wheel (34) there are receiving pockets (40) arranged next to one another in the circumferential direction, each for a lying chain link (41) of the drive chain (36). [4] Hand lifting device (15) according to claim 3, wherein two receiving pockets (40) immediately adjacent in the circumferential direction are provided by means of a connecting recess (42) for each stationary chain link (43) of the drive chain (36). [5] Hand lifting device (15) according to one of claims 2 to 4, wherein the circumferential recess (48) has a circumferential length which corresponds at least to the length of two directly connected chain links of the drive chain (36). [6] Hand hoist (15) according to claim 1, wherein two worm gears (60) are provided and wherein the worm (57) is arranged between the two worm gears (60). [7] Hand hoist (15) according to one of the preceding claims, wherein the load wheel (18) is designed for the use of a load chain (22), wherein in a circumferential direction (U) around the axis of rotation (D) there are arranged receiving pockets (23) for each lying chain link (24) of the load chain (22). [8] Hand lifting device (15) according to claim 7, wherein exactly three receiving pockets (23) for each lying chain link (24) are provided on the load wheel (18).

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