GB1593959A

GB1593959A - Hand grass shears driven by an electric motor

Info

Publication number: GB1593959A
Application number: GB16064/78A
Authority: GB
Original assignee: Wolf Geraete GmbH
Current assignee: Wolf Geraete GmbH
Priority date: 1977-04-25
Filing date: 1978-04-24
Publication date: 1981-07-22
Also published as: DE2718355C2; FR2388482A1; ZA782298B; FR2388482B1; BE866335A; DE2718355A1; CH627337A5; ATA281978A; NL187332C; SE7804047L; AT354176B; NL187332B; NL7804404A; SE436537B; ES469129A1

Abstract

The hand-held edging shears have a runner (24) which can be removed from the shears housing (10, 14, 18, 20) in order to make the blades (22) accessible. The runner (24) runs in a rail guide of the housing and is secured by a locking knob (50) which, when pressed down, permits the runner (24) to be removed. The handle housing (18) of the shears accommodates a mains cable (36) for the battery-charging unit (32), the mains plug (40) of which can be drawn out through a flap (38). This design thus makes it easier to exchange the blades (22). <IMAGE>

Description

(54) HAND GRASS SHEARS DRIVEN BY AN ELECTRIC MOTOR (71) We, WOLF-GERÄTE GMBH, of Gregor-Wolf-Strasse, 5240 Betzdorf, Federal Republic of Germany, a company organised and existing under the laws of the Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to hand grass shears driven by an electric motor and comprising skids for guiding the blades. Such skids permit a clean guiding of the grass shears on the ground and the cut height can be influenced by suitable inclined positioning.

In hitherto known grass shears of this type the skids either formed a part of the appliance housing or they were fixedly connected to the housing or the stationary blade, e.g. by screws. To make the blades accessible, for example, for freeing them of penetrated dirt or for grinding or replacing them, with known grass shears it was necessary to release several screws, and in general after releasing a bottom plate with the blades the transmission housing was also accessible and the transmission gears dropped out and in some cases could not be correctly replaced.

The problem underlying the invention is to improve hand grass shears driven by an electric motor of the type mentioned at the beginning so that with a more favourable guiding of the shears and simplified overall structure in particular the accessibility of the blades is improved. The invention provides hand grass shears comprising a housing for an electric motor that is connected to drive a cutting blade assembly, and a skid for guiding the cutting blade assembly over the ground, wherein the skid is slidably received in a mounting portion of the housing that is parallel to the cutting plane and is releasably lockable in a working position in that mounting portion.The housing mounting portion conveniently comprises guide grooves which extend in the longitudinal direction of the shears and the locking is effected by a detent pin which may be pushed back against the action of a spring and drops into a detent hole when the skid with its slide guides has reached the working position. The skid is conveniently constructed in such a manner that it supports the cutting blade assembly from below so that no additional screws are necessary for the mounting. After removal of the skid the blades can be simply detached from their guide and drive pins and removed downwardly. They may then be easily cleaned or a new pair of blades fitted.According to a further development of the invention different constructions of blade assemblies are provided which can be fitted selectively to the shears, in particular blades for grass cutting or for cutting hedges or the like. Due to the rapid fastening according to the invention the replacement can take place in a very short time and there is no danger of the parts being incorrectly assembled. An incorrect assembly of the transmission parts is prevented according to a further development of the invention in that an intermediate plate is provided between the transmission housing and the blade through which only the guide and drive pins of the transmission project downwardly so that even after removal of the skid and the blades the transmission parts are covered and cannot be removed from their bearings.The detent pin which is movable in a recess in the housing perpendicularly to the cutting plane, is preferably automatically lifted by an inclined cam surface of the skid on sliding the skid towards its working position, and snaps into engagement with a hole in the skid on reaching the working position.

Still further to simplify the shears, according to a further development of the inven tion the rear portion of the housing is inclined with respect to the front portion, whose lower face extends parallel to the cutting plane, at an obtuse angle so that the rear housing portion, and in particular a handle portion of the housing, forwardly and downwardly inclined when the shears are in the working position, giving a better adaptation to the natural position of the hand during cutting. The lower face of the rear housing portion is also preferably similarly inclined, facilitating guiding of the shears. This also makes it possible to extend the skid rearwardly beneath the lower face of the rear housing portion and to fit onto this extension a connection piece of an extension handle which can slide on rollers or skids and permits the shears to be operated from a standing position.

The handle portion of the housing is particularly suitable for accommodating a mains supply lead when a battery charging unit is accommodated within the housing.

The mains plug may then be withdrawn via a flap in the rear face of the housing at a point which is far removed from the blades so that there is no likelihood of damage to the mains lead even when the appliance is handled inexpertly.

Hereinafter examples of embodiments of the invention will be described with reference to the drawings, wherein: Figure 1 is a perspective view of hand grass shears constructed according to the invention with the mains cable for the charging unit pulled out of the grip housing; Figure 2 is a longitudinal section of grass shears according to the invention comprising detachable cutting blades and detachable skid; Figure 3 is a section along the line III-III of Figure 2.

The housing of the hand grass shears comprises a front portion 10 for receiving the electric motor 12, a rear housing portion 14 receiving the batteries 16 and upwardly angled with respect to the front housing portion, a grip housing portion 18 extending substantially parallel thereto and forming the grip and a connection housing portion 20 joining the rear ends of the housing portion 14 and the housing portion 18. The front housing portion comprises a slide surface 24 extending parallel to the cutting blades 22, with respect to which the lower side 26 of the rear housing portion 14 is set at an obtuse angle, the grip housing 18 being inclined at substantialy the same angle with respect to the cutting plane. This gives a particularly easy handling because this grip position is well adapted to the natural hand position when actuating in a bent posture.

The grip housing carries a push switch 28 which is actuable be depressing a locking means 30. In the rear housing portion 14 and the connecting housing portion 20 the charging unit 32 for the batteries 16 is accommodated. The electrical connections necessary for this purpose are not illustrated in the drawings. Said charging unit is combined with a control lamp 34 which is visible through an opening of the connecting housing portion. Said control lamp 34 can indicate the charging state of the battery or may be constructed purely as charging indication which only shows that the batteries are being charged, without indicating their charge state. Alternatively, a small voltmeter may be incorporated at this location, indicating in three colour fields, for example, yellow, red, green, different voltage states, i.e. charge conditions.Instead of a voltmeter, a plurality of luminous diodes may be provided which display the particular voltage state. It is also possible to provide only a single luminous diode as control lamp 34 which lights up as shown as the batteries have been adequately charged.

Within the hollow grip housing 18 the mains cable 36 is accommodated in coiled state and the left end thereof according to Figure 2 is anchored in means not illustrated in the housing; after opening a flap 38 disposed in the connecting housing by pulling the plug 40 the cable may be withdrawn as far as necessary to establish connection to a mains socket. After releasing the cable or the plug the cable automatically returns into the grip housing 18.

In the example of embodiment according to Figure 1 the flap 38 is made L-shaped and is pivotal about an axis 42 in the rear housing portion 14. The lower portion of the flap comprises holes 44 for inserting the plug 40. The flap may be opened by gripping the upper end, a spring preferably tending to return the flap to the closed position.

In the example of embodiment according to Figures 2 and 3 the flap 38 is made in the form of a two-armed lever pivotal about the axis 46. By pressure on the lower flap portion in the direction of the arrow C the upper flap portion is pivoted in the direction of the arrow A and the flap thus opened so that the plug 48 is accessible. In this case as well, a spring may effect the automatic return of the flap to the closure position or detent means are provided which engage in the closure position and secure the flap.

In accordance with Figure 2 the electric motor 12 drives the blades 22 in a manner known per se via a transmission 46 and an eccentric. The motor is switched on by depressing the locking means 30 and pushing the push switch 28 forwardly by means of the thumb. The blades 22 may be constructed both as grass cutting blades and as hedge cutting blades. In the example of embodiment according to Figure 2 a skid 48 covering the lower surface of the front housing portion 10 is provided and covers the blades 22 in the rear portion from below, simultaneously holding the blades.

In use, the shears are guided supported on the ground by means of the skid 48. The skid 48 is mounted displaceably in slide manner in the direction of the arrow b and in the opposite direction by means of guide strips or grooves at the lower side of the front housing portion. The working position shown in Figure 2 is fixed by a locking button 50 which is mounted displaceably vertically to the slide guide against spring pressure in the housing and, as apparent from Figure 2, engages in an upper plate of the skid. The skid 48 continues rearwardly to a connection bar 52 to which a guide rod with or without rollers may be attached.

The slide-like construction of the skids 48 makes it possible to employ these skid slides simultaneously for mounting the blades and to support the blades from below by the skids or the slide guides so that a screw mounting of the blades may be dispensed with, facilitating replacement of the blades or interchanging between grass blades and hedge blades. In order to change the blades the skid 48 is displaced after depressing the button 50 in the direction of the arrow b and withdrawn in slide manner. The blades 22 can then be detached from the transmission.

To ensure that the gears of the transmission 26 do not drop out a plate 54 is provided between the blades 22 and the transmission gears and closes the transmission housing from below. Thereafter, any replacement blade or differently constructed blade, for example, a hedge blade may be inserted as moving blade and this is done simply by pushing the skid 48 oppositely to the arrow direction b again onto the front housing portion 10. On attachment, via a suitable inclined portion of the slide guide, the arresting button 50 is depressed against the spring action and jumps automatically into its locking hole within the skid 48, thus arresting the skid 48, the blade being correspondingly held by the lateral slide guides of the skid. It is apparent from Figure 3 how lateral inwardly drawn rail guides 56 of the skid 48 are inserted into grooves 58 of the housing open towards the sides.The button 50 engages in a bore provided in a bridgelike extension 60 of the skid 48 which towards the entrance side has the inclined portion which depresses the button.

It is possible to fit to the connection piece 52 in known manner a handle so that the shears can also be employed as handle shears, establishing in likewise known manner electrical connections to a switch within the handle grip.

WHAT WE CLAIM IS: 1. Hand grass shears comprising a housing for an electric motor that is connected to drive a cutting blade assembly, and a skid for guiding the cutting blade assembly over the ground, wherein the skid is slidably received in a mounting portion of the housing that is parallel to the cutting plane and is releasably lockable in a working position in that mounting portion.

2. Hand grass shears according to claim 1, wherein the mounting portion of the housing comprises guide grooves extending longitudinally of the housing for receiving inwardly projecting slide rails of the skid.

3. Hand grass shears according to claim 1 or claim 2, wherein the releasable locking of the skid is provided by a detent pin movable in a recess in the housing perpendicularly to the cutting plane and springbiased into engagement with a hole in the skid.

4. Hand grass shears according to claim 3, wherein the hole in the skid is provided in an elevated portion of the skid that has an inclined cam surface leading thereto for lifting the detent pin against its spring bias on sliding the skid towards its working position.

5. Hand grass shears according to any preceding claim, wherein the skid supports and mounts the cutting blade assembly from below so that the blade assembly is freely removable when the skid is removed from the housing.

6. Hand grass shears according to any preceding claim, wherein the electric motor is connected to drive the cutting blade assembly via a transmission in a transmission housing that is closed with respect to the cutting blade assembly by a plate through which only guide and drive pins for the blade assembly project.

7. Hand grass shears according to any preceding claim, wherein a rear portion of the housing includes a handle that is inclined at an obtuse angle to the cutting plane and extends rearwardly and upwardly from the cutting blade assembly.

8. Hand grass shears according to claim 7, wherein the rear portion of the housing includes a battery storage zone for batteries that provide power to the electric motor, and has a lower face which extends parallel to the handle rearwardly and upwardly from the cutting blade assembly.

9. Hand grass shears according to claim 8, wherein the skid is provided with a rearward extension projecting beneath the lower face of the rear portion of the housing for mounting an extension handle.

10. Hand grass shears according to claim 8 or claim 9, wherein the handle accommodates a self-coiling mains lead connected to a battery charging unit in the housing for recharging batteries in the battery storage zone.

11. Hand grass shears according to

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. housing portion 10 is provided and covers the blades 22 in the rear portion from below, simultaneously holding the blades. In use, the shears are guided supported on the ground by means of the skid 48. The skid 48 is mounted displaceably in slide manner in the direction of the arrow b and in the opposite direction by means of guide strips or grooves at the lower side of the front housing portion. The working position shown in Figure 2 is fixed by a locking button 50 which is mounted displaceably vertically to the slide guide against spring pressure in the housing and, as apparent from Figure 2, engages in an upper plate of the skid. The skid 48 continues rearwardly to a connection bar 52 to which a guide rod with or without rollers may be attached. The slide-like construction of the skids 48 makes it possible to employ these skid slides simultaneously for mounting the blades and to support the blades from below by the skids or the slide guides so that a screw mounting of the blades may be dispensed with, facilitating replacement of the blades or interchanging between grass blades and hedge blades. In order to change the blades the skid 48 is displaced after depressing the button 50 in the direction of the arrow b and withdrawn in slide manner. The blades 22 can then be detached from the transmission. To ensure that the gears of the transmission 26 do not drop out a plate 54 is provided between the blades 22 and the transmission gears and closes the transmission housing from below. Thereafter, any replacement blade or differently constructed blade, for example, a hedge blade may be inserted as moving blade and this is done simply by pushing the skid 48 oppositely to the arrow direction b again onto the front housing portion 10. On attachment, via a suitable inclined portion of the slide guide, the arresting button 50 is depressed against the spring action and jumps automatically into its locking hole within the skid 48, thus arresting the skid 48, the blade being correspondingly held by the lateral slide guides of the skid. It is apparent from Figure 3 how lateral inwardly drawn rail guides 56 of the skid 48 are inserted into grooves 58 of the housing open towards the sides.The button 50 engages in a bore provided in a bridgelike extension 60 of the skid 48 which towards the entrance side has the inclined portion which depresses the button. It is possible to fit to the connection piece 52 in known manner a handle so that the shears can also be employed as handle shears, establishing in likewise known manner electrical connections to a switch within the handle grip. WHAT WE CLAIM IS:

1. Hand grass shears comprising a housing for an electric motor that is connected to drive a cutting blade assembly, and a skid for guiding the cutting blade assembly over the ground, wherein the skid is slidably received in a mounting portion of the housing that is parallel to the cutting plane and is releasably lockable in a working position in that mounting portion.

11. Hand grass shears according to

claim 10, wherein the mains lead terminates in a plug which is accessible via a flap in a rear face of the rear portion of the housing.

12. Hand grass shears substantially as described herein with reference to the drawings.