SPEED SELECTION DEVICE FOR MOTORIZED GARDEN EQUIPMENT

Description

[0001] The invention relates to a travel speed preselection device for motorized garden equipment, such as lawnmowers or scarifiers, which have a chassis equipped with wheels or the like, a handlebar, and a main drive for one or more working tools of the garden equipment. A wheel drive for some of the wheels on which the garden equipment rolls is derived from the main drive via controllable power transmission devices, which include travel speed control devices. Control of the power transmission devices for the wheel drive is achieved by moving and / or pivoting control elements, which are formed at least partially by the handlebar itself and / or by control elements arranged thereon.

[0002] From US Patent 4,117,652 A, a self-propelled lawn mower is known in which the speed of the wheel drive is changed by means of a first pulley arranged on the main drive and a second pulley having an adjustable effective diameter, connected to a gearbox located on the rear axle of the lawn mower and featuring a clutch. The drive belt between the main drive and the gearbox of the wheel drive is kept taut by a tensioning pulley when the effective diameter of the second pulley is changed. The clutch and the second pulley are actuated separately by Bowden cables via control elements located on the handlebar. The handlebar itself is rigidly attached to the chassis of the lawn mower.

[0003] From US Patent 4,689,939 A, a self-propelled lawn mower is further disclosed, in which a combined transmission and clutch assembly is provided, consisting of a plate clutch running in an oil bath. The plates are held apart from each other during idling and are continuously brought closer together during operation to achieve increasing speeds. This combined clutch and travel speed transmission assembly is actuated by pivoting an upper part of the handlebar in the direction of travel, so that after the clutch is engaged, a travel speed is achieved that depends both on the walking speed of the operator, who pivots the upper part of the handlebar more or less forward in the direction of travel, and on the resistance opposing the forward movement of the lawn mower.Because the plate clutch arranged in the wheel drive gearbox acts as a friction clutch over a large part of its speed control range, significant energy losses occur if the combined clutch and vehicle speed clutch is not fully engaged.

[0004] The same applies to a self-propelled lawnmower according to EP 0298016 Al, in which speed control is achieved by pivoting the wheel drive gearbox, the gearbox housing being pivotably mounted on the gearbox output shaft extending horizontally from it to the drive wheels. A gearbox input shaft extending upwards from the gearbox carries a pulley, which is driven by a belt from a pulley on the main drive. When the gearbox is pivoted further and further towards the main drive with the engine running, the belt tension decreases proportionally until the gearbox input shaft, and thus the lawnmower, finally comes to a standstill. Conversely, the mower is set in motion again by raising the gearbox and the associated increase in belt tension.The gearbox housing is connected to a movable control handle via a cable (Bowden cable) such that a forward movement of the control handle raises the gearbox and tensions the V-belt. Therefore, under the given boundary conditions regarding driving resistance and the like, there is a direct, approximately proportional relationship between the operating force and the belt tension via the cable.

[0005] Furthermore, a self-propelled lawnmower is known from EP 2 269 437 A1, which has a driving speed pre-selection device in which a section of the core in the housing of the pre-selection device is tensioned by a tensioning element whose position can be adjusted by a lever. Finally, lawnmowers with operating elements on the handlebar are known from DE 199 64 347 A1 and US 2013 / 0081500.

[0006] The drive motor of a lawnmower is typically set to a fixed speed of approximately 3000 rpm. Depending on the overall gear ratio of the power transmission to the wheel drive, this results in a fixed maximum speed for the lawnmower, which, however, is only achieved when the power transmission is running without slippage. If slippage is not achieved, the mower slows down depending on the resistance opposing its forward movement. This effect is used in the aforementioned speed control systems. If the mower is running slower than desired, the pressure on the handlebar is increased; if it is running too fast, the operating force is reduced. The mower thus adjusts itself almost automatically to the operator's walking pace.

[0007] The torque at the drive wheel required to achieve a specific driving speed depends on various factors. The rolling resistance of the mower is significant, primarily determined by its weight, wheel diameter, and wheel width. Furthermore, the slope of the terrain and the condition of the lawn naturally have a major influence. If any of these factors change, a sudden increase in driving speed can occur, which can be undesirable and dangerous.

[0008] The invention is based on the objective of creating a driving speed preselection device for motor-driven garden equipment, in which a maximum desired driving speed can be set very easily.

[0009] This problem is solved by the features specified in claim 1.

[0010] Advantageous embodiments and further developments of the invention are set out in the dependent claims.

[0011] Setting a predetermined maximum speed is particularly useful when excessive speed leads to poorer mowing and collection results. This is the case, for example, with very tall or wet grass. Mowing too fast under these conditions results in an uneven cut, or the grass catcher clogs even when only slightly full. With a maximum speed adjustable to the mowing conditions, optimal results are ensured, allowing the operator to concentrate fully on the actual mowing task.

[0012] Experience has shown that older users also desire a limited maximum speed. For this group, it's important that the mower doesn't travel too fast, even if they make a mistake. Despite the set maximum speed, the advantages of automatic speed control are retained. The driving speed adjusts automatically to the operator's walking pace, but within pre-selectable limits.

[0013] The invention will be explained in more detail below with reference to an embodiment shown in the drawing.

[0014] The drawing shows: Figure 1 a perspective view of an embodiment of a guide bar and a control bar for motorized garden equipment; Figure 2 a side view of the embodiment of the guide bar and the operating bar according to Figure 1 ; Figure 3an embodiment of a guide rail according to the Figures 1 and 2 fixed speed pre-selection device according to the Figures 1 and 2 ; Figure 4 a split view of the speed pre-selection device according to the Figures 1 to 3 ; Figure 5 a view of the vehicle speed preselection device in the position for a maximum preselectable vehicle speed; Figure 6 A view of the vehicle speed preselection device in a position for a minimum selectable vehicle speed.

[0015] Although the foregoing and following text specifically refers to garden equipment, the preselection device is equally applicable to other work equipment that has a motor-driven working tool and a controllable device connected to the output shaft of this motor, for example a gearbox, for driving the wheels on which the work equipment rolls.

[0016] In Figure 1 An embodiment of a guide handle 3 for motorized garden equipment is shown, the lower end of which is attached to the (not shown) garden equipment, while a control handle 5 is pivotably attached to its upper end via a pivot joint 4. The control handle 5 has an actuating projection 6 on the opposite side of the pivot joint 4.

[0017] In the unactuated rest state, the control handle 5 is automatically returned to a position for a standstill of the wheel drive by spring elements not shown, wherein the spring elements may either be arranged on the control handle itself or be part of an actuator (not shown) for the driving speed control, which is arranged on the chassis of the garden equipment.

[0018] The actuation point 6 of the control handle 5 is connected via a Bowden cable 1, 2 to a Figure 3only schematically represented drive motor and actuating gear unit 8 for adjusting the travel speed of the garden tool or other work equipment, wherein the drive motor can be the motor driving the working tool of the garden tool.

[0019] The Bowden cable 1, 2 comprises a flexible outer covering or sheath 1 and an inner actuating cable or core 2, which connects the operating handle 5 to a control element of the actuating gear 8.

[0020] This Bowden cable 1, 2 is therefore used to control the driving speed of the garden equipment and, if necessary, also to engage the drive mechanism.

[0021] In the course of the Bowden cable 1, 2, an embodiment of a driving speed preselection device, designated overall by 7, is arranged, as shown in the Figures 1 to 3This speed preselection device allows the maximum speed to be limited to a desired value. When the control handle 5 is removed from the position shown in the Figures 1 and 2 When the wheel drive is pivoted to the left from its stationary position shown, the Bowden cable 1, 2 is tensioned and, starting from the stationary position of the wheel drive, first engages the drive and subsequently continuously increases the speed of the wheel drive.

[0022] When the garden tool is guided via the handlebar 5, the driving speed automatically adjusts to the walking speed of the operator, since at a slower walking speed the operator moves the handlebar 5 in the Figure 2The illustration shows the handle pivoting clockwise, while at a faster walking speed the handlebar 5 pivots counterclockwise to increase the speed of the drive wheels of the garden tool.

[0023] The speed pre-selection device 7 allows you to limit the maximum speed of the garden tool, because excessively high speeds lead to poorer mowing and collection results. This is the case, for example, with very tall or wet grass. If mowing too fast under these conditions, the cut will be uneven, or the collection bag will clog even when only slightly full. With a maximum speed that can be adjusted to the mowing conditions and the operator's desired walking pace, optimal mowing results are ensured, and the operator can concentrate fully on the actual mowing task.

[0024] The travel speed preselection device 7 automatically adjusts the travel speed to the walking speed of the operator, but within preselectable limits and without the risk of an unexpectedly high increase in travel speed.

[0025] The speed pre-selection device 7 is in the Figures 3 and 4 presented in more detail, whereby Figure 4 The individual parts of the speed selection device are shown. This speed selection device 7 is preferably arranged in a housing consisting of a base body 40 and a cover 30, through which the core 2 of the Bowden cable 1, 2 extends from the actuating end 6 of the control handle 5 to the motor and adjustment gear unit 8.

[0026] The sheath 1 of the Bowden cable 1, 2 ends in the housing 30, 40 of the speed preselection device 7 and is fixed at this point in a receiving opening 24 of an angle 23 of a stop slide designated overall by 20, but is arranged to be freely displaceable in a bore 31 of the cover 30.

[0027] The stop slide 20 is displaceable in the direction of the axis of the Bowden cable 1, 2 on an inner base surface of the base body 40 of the housing and has a recess 22 with a toothing 21 arranged on its upper side.

[0028] A preselector lever, designated overall by 10, has a lever 11, a cylindrical projection 12 extending through a cylindrical bore 41 in the base of the base body 40 of the housing, a toothing 13 adjoining it which meshes with the toothing 21 of the stop slide 20, and a guide pin 15.

[0029] When the preselector lever 10 is turned, the stop slider 20 is moved along the core 2 of the Bowden cable 1, 2 together with its sheath 1.

[0030] A detent plate 53 is mounted on the guide pin 15, which has a number of detent notches 52 on part of its circumference, which cooperate with a detent projection 51 of a V-shaped detent spring 50 to allow the preselector lever 10 to detent in desired rotational positions.

[0031] The detent plate 53 has slots 54 into which protruding detent lugs 14 can engage via the toothing 13 of the preselector lever 10 in order to fix the stop slide 20 between the inner base surface of the base body 40 and the detent plate 53 and thus also the preselector lever 10 in the base body 40 in the axial direction.

[0032] The operating mode of the above-described speed preselection device is explained below using the following examples. Figures 5 and 6 described.

[0033] When the preselection lever 10 is turned, the stop slide 20 is positioned in the housing 30, 40 between the parts in the Figures 3 , 4 and 5 positions shown and defined by the detent plate 53 and the detent spring 50 along the axis of the soul 2 are displaced.

[0034] As this is shown in the Figures 5 and 6 As shown, a first end position of the pre-selection lever 10 results, which is in Figure 5 As shown, a maximum range of the driving speed control is achieved because the stop slide 20 is moved as far to the left as possible. Figure 5 is displaced and the part of the soul 2 between the driving speed preselection device 7 and the attachment 6 of the operating lever 5 is essentially tensioned.

[0035] In Figure 6The opposite end position of the control lever 10 is shown, in which the stop slide 20, and thus also the end located in the travel speed preselection device 7, is shifted as far to the right as possible. This results in a limitation of the travel speed because the section of the cable 2 between the travel speed preselection device 7 and the projection 6 of the operating lever 5 has slack in the rest position of the operating lever 5, and the initial movement of the operating lever 5 must first eliminate this slack before the actuating gear 8 is actuated by the Bowden cable 1,2. Therefore, the actuating gear 8 can only be adjusted over an initial portion of its operating range during the maximum pivoting movement of the operating lever 5, but not up to the maximum travel speed of the drive. Naturally, there are differences between the positions shown in the Figures 5 and 6The end positions of the preselector lever 11 shown allow for a number of intermediate positions specified by the detent plate 53 and the detent spring 50, each resulting in a different maximum travel distance of the actuating gear and thus a different maximum driving speed.

[0036] Although in the Figures 5 and 6 Since the displacement of the stop slide causes a sag in the inner cable 2 between the preselection device 7 and the base 6 of the operating lever 5, it is similarly possible to create such a sag at the end of the sheath 1 of the Bowden cable 1, 2 facing the actuating mechanism, whereby the in the Figures 5 and 6 The end positions of the pre-selection lever would correspond to the minimum and maximum driving speeds.

Claims

1. Motion speed pre-selection apparatus (7) for motor-driven garden tools, which have a chassis provided with wheels or the like, a handlebar (3) and a main drive for one or more working tools of the garden tool, wherein a wheel drive is derived from the main drive by means of controllable power transmission apparatuses (8), which comprise coupling apparatuses and / or motion speed control apparatuses (4), and wherein a control of the power transmission apparatuses (8) is realized by moving and / or pivoting control elements (5,6), which are formed, at least partially, by the handlebar (3) itself and / or by controls (5) arranged thereon and are connected to the power transmission apparatuses (8) by a Bowden cable (1,2), characterized in that the motion speed pre-selection apparatus (7) has a housing (30, 40) attached to the handlebar (3), in which the end of the sheath (1) of the Bowden cable (1, 2) facing the motion speed control elements (5, 6) is arranged freely movably and securably in a stop slide (20) which can be moved along the axis of the Bowden cable (1, 2) in the housing (30, 40) by means of a pre-selection lever (10), wherein the stop slide (20) is designed to create slack in the core (2) of the Bowden cable (1, 2) during adjustment towards lower maximum motion speeds.

2. Pre-selection apparatus (7) according to claim 1, characterized in that an operating bar (5) is pivotably attached to the upper end of the handlebar (3) by means of a pivot joint (4), in that the operating bar (5) has an actuating extension (6) on the opposite side of the pivot joint (4), and in that the housing (39, 40) is arranged in the route of the Bowden cable (1, 2) between a drive motor and actuating gear unit (8) and the actuating extension (6).

3. Pre-selection apparatus (7) according to claim 1 or 2, characterized in that the stop slide (20) is movably mounted in the direction of the axis of the Bowden cable (1,2) on an inner base area of the main body (40) of the housing and has a recess (22) with teeth (21) arranged on its upper side, in that the pre-selection apparatus (7) has a pre-selection lever (10) with a lever part (11), a cylindrical extension (12) which extends through a cylindrical bore (41) in the base area of a main body (40) of the housing (30, 40), adjoining teeth (13), which mesh with the teeth (21) of the stop slide (20), and a guide pin (15).

4. Pre-selection apparatus (7) according to claim 3, characterized in that a latch plate (53) is attached in a rotationally fixed manner to the guide pin (15), which has a number of latching notches (52) on part of its circumference, which interact with a latching projection (51) of a V-shaped latch spring (50) to allow the pre-selection lever (10) to engage in desired rotational positions.

5. Pre-selection apparatus (7) according to claim 4, characterized in that the catch plate (53) has slots (54), in which latching lugs (14) projecting beyond the teeth (13) of the pre-selection lever (10) can be engaged such that the stop slide (20) is fixed in the axial direction between the inner base area of the main body (40) and the catch plate (53) and thus also the pre-selection lever (10) in the main body (40).

6. Pre-selection apparatus (7) according to one or more of the preceding claims, characterized in that the housing (39, 40) can be arranged in the route of the Bowden cable (1, 2) between a variable speed transmission (8) and the actuating extension (6).