Patent Application
20240199398
The invention relates to an extending fork for a fork-lift truck or pallet truck. Such an extending fork is length-adjustable and enables the length of the forks of a fork-lift truck or pallet truck provided therewith to be adapted to the goods to be transported.
In practice many goods are transported on pallets or other carriers. Use is here made in practice of different types and dimensions of for instance such pallets. Many pallets also have different lengths and widths. It can also be advantageous to pick up pallets from the front or conversely from a side. This means that standard forks of a fork-lift truck or pallet truck may for instance protrude beyond the pallet during pick-up thereof, this resulting in a risk of damage to other goods and/or persons. In the case of a relatively large pallet a standard fork may also support such a pallet only partially, this causing a pallet to overhang over the standard fork and creating the risk of the pallet falling off the fork. This entails a safety risk and the risk of damage to products.
Known in practice are fork-lift trucks, among other things, which for said reasons are provided with length-adjustable forks. These length-adjustable forks are manually adjustable or provided with a drive. Such a drive requires a complex drive system which usually takes a hydraulic form, wherein the extendable forks are coupled with their drive to the system of for instance the fork-lift truck. This is relatively complex and expensive. This also requires additional maintenance and entails the risk of failure.
Also known is a manually length-adjustable fork for a fork-lift truck, for instance described in NL 2011022. In such a fork a slidable fork part can be displaced relative to a fixed fork part. Because the adjustment can be performed manually, it is possible to dispense with a relatively complex drive. This makes such an extendable fork effective and relatively simple. A problem is here that a fork-lift truck driver for instance has to get off the fork-lift truck for the purpose of adjusting the fork. Especially in the case that dimensions of the pallets to be displaced keep varying does this manual adjustment have to take place frequently. This is time-consuming for the driver, which adversely affects the efficiency of the logistical function. There is also a safety risk in that the fork-lift truck must be stationary and the driver must exit the cab. Because this is not experienced as user-friendly in all cases, there is a risk that a driver will not consistently adapt the length of the fork to the load to be picked up, for instance in the case of a one-time variation in dimensioning. Risks in respect of safety and damage hereby continue to exist.
The present invention has for its object to provide an extending fork for a fork-lift truck or pallet truck whereby the above stated problems are obviated or at least reduced.
This object is achieved with the electric extending fork according to the invention for a fork-lift truck or pallet truck, wherein the electric extending fork comprises:
Providing a base fork and sliding fork connected slidably thereto makes the length of the fork of a fork-lift truck or pallet truck adjustable. This adjustment makes it possible to adapt the fork length to the goods to be transported, for instance to the dimensions of a pallet to be displaced. This reduces the health risk to users of such a pallet truck or fork-lift truck, and to bystanders. The risk of damage to the goods to be displaced during picking up, moving, setting down and/or maneuvering these goods is additionally reduced.
The sliding fork of the electric extending fork according to the invention is slidable relative to the base fork. This sliding relates to the sliding out, i.e. extending of the fork, and to the sliding in, i.e. the shortening of the overall fork length. This sliding is achieved with the electric extending fork according to the invention using an electrical drive system which is configured to slide the sliding fork out and in relative to the base fork. The use of an electrical drive system renders unnecessary the need to provide a hydraulic coupling between the extending fork, or at least the drive system thereof, and the hydraulic system of for instance a pallet truck or fork-lift truck. By providing an electrical drive system it is possible to suffice with a relatively simple coupling to for instance the battery of such a fork-lift truck or pallet truck. It is also possible, if desired, to provide a separate battery in the electric extending fork according to the invention.
The electrical drive system is further provided with a coupling to the sliding fork. This coupling is preferably a flexible coupling. Such a (flexible) coupling has the advantage that (a part of) the drive system can be positioned freely relative to the sliding fork. In a currently preferred embodiment an electric motor is provided at or close to the upper outer end of the vertical part of the fork and, using the (flexible) coupling, the movement is transmitted from a substantially vertically oriented shaft to an extending movement in a substantially horizontal direction. Making such a right-angled coupling flexible enables any possible bending of the fork as a result of the goods placed thereon to be accommodated without damage to the drive system. This is relevant inter alia because such bending will usually occur in practice, whereby sliding in and/or sliding out of the sliding fork relative to the base fork will result in more resistance. Owing to the flexible coupling, this can be obviated cost-effectively in relatively simple manner. This makes application of an electrical drive system feasible in practice without extremely large powers having to be used.
Application of the electrical drive system makes the electric extending fork according to the invention length-adjustable in relatively simple manner. This prevents for instance a driver of a fork-lift truck from having to get off the fork-lift truck in order to change the length of the fork. This increases the safety of users and drivers during displacement of goods.
In order to further reduce the (undesirable) bending of the fork in practice a support element is arranged in or on the base fork. This support element provides additional support with respect to the sliding fork, whereby bending is reduced considerably. This simplifies sliding in or sliding out of the sliding fork relative to the base fork. Additionally, such a support element makes it possible to suffice with a smaller installed power for the electrical drive system. In a currently preferred embodiment the support element is provided as a support roller. Such a support roller can be embodied according to the invention as a roller element, wheel, barrel or other suitable support roller. Alternatively, the support element can comprise a different suitable element, for instance a wear strip or ball race. A plurality of support elements, such as support rollers or shared rollers, can optionally also be provided in order to thereby further increase the support for the sliding fork and particularly to further prevent bending of the fork.
An additional advantage of the electric extending fork according to the invention is that it can be applied in effective manner to both new and already existing fork-lift trucks or pallet trucks. This is made possible inter alia in that a hydraulic coupling between the extending fork and the fork-lift truck or pallet truck can be dispensed with. This increases the utility of the extending fork according to the present invention. In addition, a user can also perform the installation and/or removal of the extending fork on their own fork-lift truck or pallet truck in relatively simple manner. This increases the convenience of use and reduces costs of for instance maintenance.
Providing an electrical drive system additionally enables the sliding out and sliding in of the sliding fork relative to the base fork to be controlled in simple manner. This can for instance done from the driver's position by a user of a fork-lift truck. It is also possible, if desired, to provide a separate remote control whereby the length of the forks can be adjusted. If desired, such a remote control interacts with the control of the fork-lift truck so that a change in the length of the forks is for instance only possible when the fork-lift truck is stationary.
The electric extending fork according to the invention can be applied in a right-angled design for a fork, wherein a vertical part is connected to the carrier frame of a fork-lift truck and the horizontal part is used for displacing the goods, and also in a substantially horizontal fork, wherein the carrying part is connected directly to the frame, i.e. without interposing of a vertical part. This latter variant can for instance be advantageously applied in a pallet truck.
It has been found that in a currently preferred embodiment according to the invention the flexible coupling can be embodied as a cardan joint in effective manner. Experiments have shown that such a cardan joint provides on one hand an effective coupling and on the other imparts sufficient flexibility to be able to accommodate any bending of the forks without damage to the drive system. The cardan joint is preferably embodied as a double cardan joint. Likewise, such a flexible coupling in the form of a double cardan joint is preferably also applied in an above stated substantially horizontal fork, wherein the horizontal part is connected directly to the frame of the fork-lift truck or pallet truck. Alternative flexible couplings for instance make use of a toothed belt, chain or other suitable transmission. Further alternative couplings may include application of one or more gears of gearing wheels.
In an advantageous embodiment according to the invention the drive system comprises a spindle drive.
The spindle drive is preferably provided in the drive system since such a spindle drive enables a reliable sliding of the sliding fork relative to the base fork. This sliding can also be realized in sufficiently accurate manner. For this purpose different types of spindle can be applied, for instance so-called ball screw spindles or trapezoidal spindles. It will be apparent that other types of spindle can also be applied according to the invention. The spindle is preferably driven via the flexible coupling, particularly via a double cardan joint, from an electric motor, or alternatively via a toothed belt, chain or gears.
In an advantageous embodiment according to the invention the sliding fork is further provided with at least one slide block for sliding the sliding fork relative to the base fork.
Providing the sliding fork with at least one slide block makes it possible to realize an effective sliding of the sliding fork relative to the base fork. The slide blocks here limit the clearance and thereby for instance the sagging or buckling of the sliding fork relative to the base fork during extending thereof. The clearance between sliding fork and base fork is further reduced here, this also limiting the overall bending further. This additionally has a positive (reducing) effect on the electric power required for the electrical drive system which is applied in the electric extending fork according to the invention.
Additionally or in an alternative embodiment according to the invention, the sliding fork is provided with at least one bearing for sliding the sliding fork relative to the base fork. Such a bearing can be applied in addition to or instead of the above stated slide block. Such a bearing can for instance be a ball bearing or spherical roller bearing. It will be apparent that other suitable types of bearing can also be used. The clearance is limited further with such a bearing.
In an advantageous embodiment according to the invention the slide block and/or bearing is provided on both the side of the extending fork directed upward during use and the side directed downward during use. Providing such a slide block and/or bearing on both sides provides a better support for the sliding fork relative to the base fork and further reduces the risk of buckling or bending occurring. As already stated above, this has a positive effect on limiting the electric power required.
In an advantageous embodiment according to the invention the base fork is provided with a guide track configured to guide the sliding fork.
Providing a guide track enables the relative movement between the sliding fork and the base fork to take place in controlled manner. Such a guide track is preferably milled into the material of the base fork. Such a guide track can hereby be provided in effective manner and a form locking can additionally be realized, if desired.
In a currently preferred embodiment the sliding fork is provided with a slide block and/or bearing which moves over the guide track. Such a combination of guide track with slide block and/or bearing enables an effective sliding of the sliding fork relative to the base fork.
In a further advantageous embodiment according to the invention the spindle is arranged in a housing.
Arranging the spindle in a housing shields it from the surrounding area. This has the advantage, among others, that contamination of the spindle is counteracted. This safeguards the lifespan and accuracy of the spindle and additionally significantly reduces the maintenance required. This therefore also increases the user-friendliness of the electric extending fork. In a currently preferred embodiment the housing is embodied as a type of tube or other tubular element which substantially surrounds the spindle. Additional strength is also imparted to the extending 20 fork, this further reducing bending.
In a further advantageous embodiment according to the invention the spindle housing is provided with a bending position.
By providing a specific bending position any bending which may occur can be fixated at a specific location. This considerably reduces the risk of damage occurring to the spindle. In practice, this prevents damage to the spindle, even when the forks are overloaded. Such a bending position can be realized in effective manner by arranging a weakening in the spindle housing, for instance by providing a recess and/or smaller wall thickness therein.
In a further advantageous embodiment according to the invention the extending fork is substantially closed on the side directed downward during use.
Additional strength is imparted to the extending fork by providing a substantially closed fork, i.e. a fork which is also substantially closed on the side directed downward during use. This results in, among other things, a further reduction of the possibly occurring bending, this enabling effective use of the extending fork. This additionally realizes a further shielding of the spindle, among other things, whereby contamination, or at least the risk thereof, is greatly reduced. This extends the lifespan of the extending fork and/or limits the maintenance required.
In a currently preferred embodiment the sliding fork is provided as a profile, and is preferably manufactured from a tube profile. Such a sliding fork can hereby be produced in cost-effective manner. In such a production process use is for instance made of a folding or bending process and/or a rolling process and/or extrusion process. A profiled tube profile can if desired be provided here for additional functionality and/or additional strength of the tube profile. A suitable design of such a tube profile makes it possible to further reduce material costs and/or increase the strength of the fork. The wall thickness of such a tube profile preferably lies in the range of 3-10 mm, for instance 3-4 mm. If desired, the tube profile can also be given wholly or partially different dimensions.
In a further advantageous embodiment according to the invention the drive is operatively connected to the sliding fork by means of a pin coupling.
By providing a pin coupling the drive system is connected to the sliding fork in effective manner. By controlling the drive system the movement initiated with the drive system is transmitted by the pin coupling to the sliding fork, which will then slide in or slide out. In a currently preferred embodiment the pin coupling is arranged in or on the nose part of the sliding fork. This makes it possible to realize an effective sliding of the sliding fork relative to the base fork. The pin coupling has the further additional advantage that the sliding fork can be uncoupled from the drive system in simple manner by removing the pin. This is for instance advantageous for maintenance purposes and/or for exchanging the sliding fork.
In a further advantageous embodiment according to the invention the electric extending fork is provided with a detector.
By providing a detector information regarding for instance the position and/or bending of the extending fork can be obtained. The detector can here make use of a magnet and/or microswitch and/or other suitable element. The detector is here preferably connected to the control of the fork-lift truck or pallet truck.
The extending fork is optionally provided with a locking mechanism for fixing the sliding fork at a desired position relative to the base fork. For this purpose a plurality of locking positions are preferably provided, or the sliding fork can be fixed at any desired position relative to the base fork. This preferably makes it possible to lock the position of the sliding fork relative to the base fork at more than a minimum and maximum length of the fork.
Providing a locking mechanism enables a safe operation. Providing the locking mechanism with a plurality of locking positions enables a flexible adaptation to the diverse dimensionings which occur in practice. Use can for instance be made here of for instance a pin-hole connection, wherein a plurality of holes are provided in a tube profile of the fork, a locking mechanism with which a locking is provided, or another suitable locking system.
The locking mechanism optionally further comprises a locking drive, wherein the locking drive can control the locking mechanism remotely. This makes it possible for a driver or user to activate or conversely deactivate the locking mechanism in effective manner. It is possible here for the driver to control the locking mechanism from the cab of a fork-lift truck. This further makes the use user-friendly in practice. The locking mechanism is further preferably provided with a sensor configured to detect a correct locking. This further increases the safety for remote control of the locking mechanism, for instance with a remote control from the cab of a fork-lift truck. It will be apparent that such a sensor can be provided in several ways, for instance on the basis of a contact or another signal.
The locking mechanism is preferably further provided with a battery. By providing a separate energy supply for the locking mechanism the modular sliding fork according to the invention can act substantially independently of drives of the fork-lift truck or pallet truck in effective manner. The simple installation and removal is hereby preserved for the modular sliding fork according to the invention.
An additional sensor system is optionally provided for the extending fork according to the invention. It is possible here to envisage a length measurement using for instance a cable transducer, a laser, an ultrasonic sensor. It is also possible to detect bending using for instance an angle measurement and a weight measurement. This can further improve the safety of the extending fork according to the invention. If desired, such a sensor system makes use of a transmitter and/or transmitter/receiver for the purpose of providing a wireless sensor system which is for instance in operative connection with a control.
The invention further relates to a fork-lift truck or pallet truck comprising an electric extending fork in an embodiment according to the invention.
Such a fork-lift truck or pallet truck provides similar advantages and effects as described for the electric extending fork.
The invention further also relates to a method for displacing goods with a fork-lift truck or pallet truck, comprising of:
Such a method provides the same effects and advantages as described for the electric extending fork and/or fork-lift truck or pallet truck.
Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which:
The following description is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. While the disclosure is described as having exemplary attributes and applications, the present disclosure can be further modified. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice of those skilled in the art to which this disclosure pertains and which fall within the limits of the appended claims. Accordingly, the following description of certain embodiments and examples should be considered merely exemplary and not in any way limiting.
Electric extending fork 2 (
Carrying part 6a is connected via connecting part 24 to mounting part 6b. On the opposite, front side of carrying part 6a horizontal for part 6a is provided with support element 26 which is provided in the shown embodiment with support element(s) in the form of support roller 26a,b on either side of horizontally oriented carrying part 6a. In this embodiment support rollers 26a,b are embodied as wheels which are arranged rotatably on wheel shaft 28 and are in contact with sliding fork 4 via contact surface S.
Electric motor 12 drives a vertically oriented drive rod 30 (
If sliding fork 4 must be slid out in direction A for the purpose of lengthening the overall fork length L, drive system 10 is activated. Electric motor 12 will hereby rotate drive rod 30 in direction B, wherein this movement in converted via cardan joint 32 into rotation C of spindle 34. This rotation then results in nut 36 of spindle 34 extending in direction D, causing rod 38 to extend as well. Coupling to first coupling part 42 and second pin coupling part 46 creates a connection to sliding fork 4, which will then slide out in direction A. This movement of sliding fork 4 in direction A is supported on the front side of fork part 6a using support rollers 26 and supported on the rear side of sliding fork 4 by bearing 16. In this embodiment spindle 34 is arranged in a tubular housing 52. Arranged in this housing is a recess or opening 54, which defines thereby a bending position. Bearing 16 can be set or adjusted via element 56 (
In a second embodiment electric extending fork 102 (
A further distinction from second embodiment 102 is formed by arranged magnets 106 or magnetizable parts. These can function as locking and/or detector. It is also possible to apply microswitch 108 in order to perform further detection of position, length, bending and other relevant parameters therewith. Further arranged in the shown embodiment of extending fork 102 is a clip element 110 which can be placed in a recess 112 of tube 52. Spindle 34 can hereby be positioned in fixed horizontal fork part 6a in efficient manner.
In a third embodiment for electric extending fork 202 (
In the various shown embodiments for electric extending fork 2, 102, 202 sliding fork 4 is provided from sheet material, for instance by folding it into a desired profile. In the shown embodiments fork 2, 102, 202 is substantially closed all the way around, i.e. also closed on the side directed downward during use.
Fork-lift truck 302 (
Also provided for fork-lift truck 302 in the shown embodiment is sensor system 318 comprising possible sensors/detectors in sensor part 320, sensor receiver 322 and optional power supply battery 324. Sensors 320 are for instance one or more of an inclinometer, strain gauges, cable transducer, laser, ultrasonic sensor. Sensors 320 can be aimed at measuring an occurring load, fork length, position relative to a ground surface and the like. It will also be apparent that parts or the whole sensor system 318 can be arranged at a different location or distributed over multiple locations. Strain gauges will thus for instance preferably be arranged in or on a vertical part of forks 2, 102. Fork-lift truck 302 can optionally communicate via signals 326 with (external) control system 328, for instance an ERP system. Arranged in cab 304 in the shown embodiment is control box or interface 330, whereby a user or driver is informed of for instance the correct operation of electric extending fork 2, 102. A further sensor 332 can be provided on fork part 4, as can an optional laser pointer 334 close to the nose of sliding fork 4. In this embodiment drive system 10 is preferably operatively connected to battery 336 of fork-lift truck 302.
It will be apparent that the diverse described or otherwise cited possibilities and options can be combined into new embodiments according to the invention in different combinations.
Pallet truck 402 (
The present invention is by no means limited to the above described preferred embodiments thereof. The rights sought are defined by the following claims, within the scope of which many modifications can be envisaged.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2033726 | Dec 2022 | NL | national |
