GB2617171A

GB2617171A - Safety device for a CNC machine

Info

Publication number: GB2617171A
Application number: GB2204672.6A
Authority: GB
Inventors: Harisson De Sousa Costa Helbert
Original assignee: HM Tech Ltd
Current assignee: HM Tech Ltd
Priority date: 2022-03-31
Filing date: 2022-03-31
Publication date: 2023-10-04
Also published as: GB202204672D0

Abstract

The safety device 100 includes a handle portion 102 movable between a first position and a second position. A first safety switch is configured to be activated when the handle is in the first position (as in Figure 4) and deactivated when the handle is in the second position (as in Figure 7). A bumper bar is configured to cut power to the CNC machine (10, Figure 1) when the bumper bar determines application of pressure thereto. The handle portion may be a U-shaped or C-shaped structure with a pair of pivot points 104 for mounting to the machine. The handle portion may operatively engage first and second parts of a drive mechanism which may be a rack and pinion. The device may be mounted to a gantry of a CNC machine. The second position of the handle may be between 25 and 45 degrees such as 25 degrees. The bumper bar may extend around the entirety of the handle and include an actuable part to engage a second safety switch. The second safety switch may be configured to cut power or apply power to the CNC machine when the bumper bar is actuated.

Description

SAFETY DEVICE FORA CNC MACHINE

FIELD

The present invention relates to generally to a CNC machine and aspects thereof. More particularly, the present invention relates to an industrial grade CNC machine that can be transported between locations such that a single machine can be transported between work sites to facilitate local CNC routing support.

BACKGROUND

CNC machines used for woodworking typically have a large form factor which dictates that they can only be feasibly operated from a fixed location. i.e., within a factory. A conventional CNC machine comprises a fixed bed for holding a material piece and a 3-axis (X, Y, Z) CNC controller that receives g-code files programmed by a CAD/CAM pc software. The gantry is mechanically configured to move on 3 different axis along the bed, i.e., the CNC controller, embedded within the gantry body, is programmed to move the CNC head (Z-axis) in the X and Y axis together with the gantry and in another axis, i.e., the CNC head is the Z axis that moves the cutting tool in the vertical motion and it comprises of a CNC spindle and tool.

Conventional CNC machines are typically controlled by a separate control tower that incorporates control circuitry. The control tower is where all the electronics are embedded and typically hardwired to the CNC body outside of the machine footprint to provide communication and exchange data between the control tower and CNC controlled axis.

Such conventional CNC machines cannot be easily transported between locations: i) as they are mechanically designed and welded together making them impossible to be dismantled; ii) the space required by the bed and control tower is significant; and hi) current CNC machine designs would pose a safety risk to non-skilled operatives on site.

It is against the aforementioned background that the present invention has arisen.

SUMMARY

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. The detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended to be given by way of example only.

Embodiments of the present invention provide a CNC machine that can be easily transported between different locations and used in a safe and reliable manner. A critical part of this innovation is the provision of a multi-function safety handle. The safety handle may provide the following functionality: i) engagement of the gantry to the Y axis machine body frame through clamping force action, enabling motion around a single axis; ii) activate and deactivate a safety switch; Hi) housing a bumper rubber strip which, when activated, cuts motion to the CNC machine; and iv) a conventional handle for the user to grasp and transport the CNC gantry.

In a first aspect of the invention there is provided a safety device for a CNC machine comprising: a handle portion movable between a first position and a second position; a safety switch configured to be activated when the handle is in the first position and deactivated when the handle is in the second position; and a bumper rubber bar configured to cut motion to the CNC machine when the bumper determines application of pressure thereto.

The present invention facilitates the use of CNC machines outside of the conventional factory settings. There are many safeguards that need to be put in place to mitigate the risk of injury to an operator or bystander of a CNC machine. In a conventional factory setting, CNC machines are isolated from bystanders and fixed guards are put in place to provide. This is not possible in the case of a mobile CNC machine that may be used on many different sites. The present invention provides multi-modal safety protection for CNC operators and bystanders on building sites. This is achieved firstly through the need for an operator to physically engage handle portion of a safety device before the CNC machine can be activated. Secondly, the bumper provides a kill switch in the event of any form of body contact thereto.

In one embodiment, the handle portion comprises a substantially U-shaped or C-shaped structure and a pair of pivot points for mounting the handle portion to a CNC machine gantry.

In one embodiment, the handle portion is operable to operatively engage a first part of a drive mechanism with a second part of drive mechanism when the handle portion is in the first position and to disengage the first part of the drive mechanism from the second part of the rack and pinion drive mechanism when the handle portion is in the second position.

In one embodiment, the first part of the drive mechanism is a pinion, and the second part of the drive mechanism is a rack.

In one embodiment, the safety device is mounted to a gantry forming part of a CNC machine.

In one embodiment, the pair of pivot points of the handle portion are joined by an elongate member that is fixed to move around a same axis as the handle portion as the handle portion is moved between the first position and the second position.

In one embodiment, the first position of the handle portion is substantially parallel to a ground surface and the second position of the handle portion is angularly offset from the ground surface by between 25 to 45 degrees. Preferably, the second position of the handle portion is angularly offset from the ground surface by 35 degrees.

In one embodiment, the handle portion comprises at least two independent handle portions, wherein movement of any one handle portion to the second position causes the CNC machine to be deactivated and wherein the CNC machine is only activated when all handle portions are moved to the first position.

In one embodiment, the bumper bar extends substantially around the entirety of the handle portion, wherein the handle portion comprises a supporting part and an actuable part that is operable to engage a second safety switch when the actuable part is actuated.

In one embodiment, the second safety switch is configured to cut motion to the CNC machine when the bumper bar is actuated.

In one embodiment, the second safety switch is configured to provide power to the CNC machine when the bumper bar is actuated.

Another aspect of the invention provides a CNC machine including all the aforementioned features.

In one embodiment, the CNC machine further comprises a gantry mounting the safety device, wherein the gantry comprises a steel tube structure housing all electronics, CNC controller and CNC head (Z-axis), that is mechanically configured to move in X, Y and Z directions along the CNC bed structure, and control circuitry to drive at least 3 servo electric motors.

In one embodiment, the gantry comprises a pair of pinions, one at each end of the gantry, and the CNC machine further comprises a bed for receiving a work piece, wherein the bed comprises a pair of parallel racks, each rack being arranged and configured to receive a respective one of the pinions of the gantry, and wherein the gantry is configured to be selectively electrically and mechanically connected to the bed and disconnected and removed from the bed for stowage and transport.

In one embodiment, the bed further comprises a plurality of support legs, each support leg being configured to fold substantially flat against an underside of the bed for stowage and transport.

In one embodiment, the CNC machine further comprises a gas strut between each support leg and the underside of the base, the gas strut being configured to hold the respective support leg in a deployed configuration.

In one embodiment, the CNC machine further comprises a pair of guide rails and a pair of guides, wherein each of the pair of guides is configured to slide along a respective guide rail and comprises a first part of a locking interface for engagement with a support block of the gantry, wherein the support block engages the guide when the handle is in the second position and the support block is spaced apart from the guide when the handle is in the first position In one embodiment, the support block further comprises a second part of the locking interface in the form of a locking pin that projects downwardly and engages the first part of the locking interface when the handle is in the second position.

In one embodiment, the support block further comprises a second part of the locking interface in the form of a locking pin that projects downwardly and engages the first part of the locking interface when the handle is in the second position.

FIGURES

Aspects and embodiments of the invention will now be described by way of reference to the following figures FIG.1 illustrates a CNC machine in an operating configuration according to aspects and embodiments of the invention.

FIG. 2 illustrates a CNC machine in a transport configuration according to aspects and embodiments of the invention.

FIG. 3 illustrates an isometric view of a safety device for the CNC machine of aspects and embodiments of the invention when the safety device is in unclamped configuration.

FIG. 4 illustrates a side view of a safety device for the CNC machine of aspects and embodiments of the invention when the safety device is in unclamped configuration.

FIG. 5 illustrates a top view of a safety device for the CNC machine of aspects and embodiments of the invention when the safety device is in unclamped configuration.

FIG. 6 illustrates an isometric view of a safety device for the CNC machine of aspects and embodiments of the invention when the safety device is in a clamped configuration.

FIG. 7 illustrates a side view of a safety device for the CNC machine of aspects and embodiments of the invention when the safety device is in a clamped configuration.

FIG. 8 illustrates a gantry according to aspects and embodiments of the invention.

FIG. 9 illustrates the side rails of aspects and embodiments of the invention.

FIG. 10 illustrates a CNC head according to aspects and embodiments of the invention.

DESCRIPTION

The following description of the preferred embodiment(s) is merely exemplary in nature and is no way intended to limit the invention, its application, or uses.

The description of illustrative embodiments according to principles of the present invention is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description of embodiments of the invention disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as "lower," "upper," "horizontal," "vertical," "above," "below," "up," "down," "top" and "bottom" as well as derivatives thereof (e.g., "horizontally," "downwardly," "upwardly," etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation unless explicitly indicated as such. Terms such as "attached," "affixed," "connected," "coupled," "interconnected," and similar refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. Moreover, the features and benefits of the invention are illustrated by reference to the exemplified embodiments. Accordingly, the invention expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features; the scope of the invention being defined by the claims appended hereto.

As shown in FIG. 1, a CNC machine (10) according to aspect and embodiments of the invention comprises a bed (12) supported by at least four support legs (14) with each support leg (14) terminating at a castor (16). The bed (12) is bounded laterally by a pair of side rails (18) each mounting a rack (20) along its length, i.e., along the y dimension. A gantry (22) spans laterally, i.e., in the x dimension, between the pair of side rails (18) and is mounted thereon by a pair of guide rails (24) each running parallel to a respective rack (20). Each of a pair of first pinions (26) engage with a respective rack of the pair of racks (28to enable movement of the gantry (22) longitudinally along the bed (12) of the CNC machine (10).

A guide (36) is configured to slide along each of the guide rails (24). Each guide (36) comprises a machined aluminium plate (38) sitting atop a channelled block (40). The channelled block (40) comprises a channel (42) machined to match the profile of the guide rail (26) and the aluminium plate (38) is configured to move with the channelled block (40). The gantry (22) is supported by a pair of guides (36) to facilitate smooth motion of the gantry longitudinally relative to the bed (12). This is shown more clearly in FIG. 9 The gantry (22) further mounts a CNC head (30) that is movable along the length of the gantry (22), i.e., laterally relative to the bed (12). The top surface of the gantry (22) mounts a guide rail (32) and a rack (34). A pinion (not shown) is configured to engage the rack (34) when a safety device (100) of aspects and embodiments of the invention associated with the CNC head (30) is in an operating position. A guide (not shown) having a similar construction to the guide (36) is configured to slide along the guide rail (32) to facilitate smooth motion of the CNC head (30) along the length of the gantry. The CNC head (30) further comprises a tool attachment (44) configured to receive cutting, routing, sanding, grinding, etc tool bits. The tool attachment (42) is configured to move upwardly and downwardly, i.e., in the z dimension, to enable control over depth of cutting. This is shown clearly in FIG. 10. A pair of guides (56) are configured to slide vertically up and down, i.e., in the z dimension, along a pair of vertical guide rails (58) housed within the CNC head (30) In some embodiments, the tool attachment (44) may be rotated from vertical to provide an angled cut or surface modification to a work piece. In some embodiments, the CNC head (30) itself may be rotated from vertical to provide an angled cut or surface modification to a work piece. The CNC head (30) further comprises quick release electrical connections to enable quick and easy electrical connection to the bed (12) of the CNC machine (10). The CNC head (30) is shown in detail in FIG. 10.

As shown in FIG. 2, the CNC machine (10) is configured to be portable to enable it to be transported between sites. Each of the support legs (14) is connected to an end of the bed (12) by way of a quick release clamping system and/or anti-theft bolts. At least one gas strut (46) is provided between each support leg (14) and the bed (12) as shown in FIG. 2. Each support leg (14) may be folded upwards to compress the height of the CNC machine (10). The gantry (22) may be lifted off the side rails (20). The side rails (20) may be lifted off the bed (12). The CNC head (30) may be removed from the gantry (22). Such detachments further aid in transportation of the CNC machine (10).

The gantry (22), as illustrated in FIGs 1 and 2, mounts several handle operated safety devices (100a, 100b, 100c). In the illustrated embodiment, three safety devices (100) are shown, one at each end of the gantry (22) and the other as part of the CNC head (30) Each of the safety devices (100a, 100b) comprises a handle portion (102) which is substantially U-shaped or C-shaped and pivotably mounted to the gantry (22) by a pair of pivot points (104). The pair of pivot points (104) is joined by an elongate member (106), i.e., a machined bar, fixed to rotate around the same axis as that defined by the pair of pivot points (104). The safety device (100a, 100b) comprises a safety switch which, when the handle portion (102) is in a first position, i.e., angled upwardly approximately 35 degrees from a ground surface, as shown in FIGs. 3 and 4, is activated to cut power to the CNC machine (10). When the handle portion (102) is rotated downwards around the pair of pivot points (104) to a second position, i.e., substantially parallel to a ground surface, as shown in FIGs. 6 and 7, the safety switch is deactivated. This has the effect of only applying electrical power to an electric servo motor associated with the safety device (100a, 100b) when the handle portion (102) is in the second position.

When the safety device (100a, 100b) is in the first position, an aluminium plate (106) forming part of the safety device (100) assembly is spaced apart from the guide (36) such that a gap is defined therebetween. In this position, the pinion (26) is lifted out of engagement with its associated rack (20) such that there is no contact therebetween. When the safety device (100a, 100b) is in the second position, the guide (36) and the aluminium plate (106) are moved into engagement and a locking pin (108) forming part of the aluminium plate (106) is lowered through a slot, hole, or keyway (48) through the guide (36) to form a locking engagement therebetween. When a servo motor provides power to the pinion (26), the engagement of the

S

pinion with the rack (20) and the sliding motion of the guide (36) along the guide rail (24) facilitates smooth movement of the gantry (22) relative to the bed (12).

The safety device (100c) functions in a similar manner to that described with reference to safety devices (100a, 100b). As shown in FIG. 8, a first guide rail (50) and a rack (52) are positioned atop the gantry (22) and extend along the length of the gantry (22). A second guide rail (54) is positioned on the front of the gantry (22) and extends along the length of the gantry (22). A first guide is configured to slide along the first guide rail (50) and a second guide is configured to slide along the second guide rail (54). The first and second guide may be joined by a common plate (54) A pinion, at least partially contained within the CNC head (30) engages with the rack (52) when the handle portion (102) of safety device (100c) is in the second position. When the handle portion (102) is lifted to the first position, the pinion is lifted away from the rack (52) and a safety switch within the CNC head (30) is activated to cut all power to the CNC machine (10) in the same manner as safety devices (100a, 100b).

The handle portion (102) of each safety device (100a, 100b, 100c) also provides a bumper strip that is spaced apart from a safety switch or electrical contact. In the event of contact with the bumper strip, the safety switch or electrical contact is activated and sends an electrical signal to the control circuitry of the CNC machine (10) which immediately cuts all power thereto.

Further safety measures in the form of safety belts (110) may be provided to the side rails (18) of the bed (12). The safety belts (110) are defined by a flexible belt (112) running along the length of each side rail (18). Contact with said flexible belt (112) causes an electrical signal to be sent to control circuitry of the CNC machine (10) and results in power being cut to the CNC machine (10). The CNC machine (10) is further provided with at least one emergency stop button (114).

Any time that a safety device (100a, 100b, 100c, 110, 114) is activated, it is necessary to perform a reset of the CNC machine (10) before power may be restored thereto. In one example, a reset may be performed by turning a power key off and then on again. In another embodiment, all three of the safety devices (100a, 100b, 100c) must be first moved to the second position before a reset button, or power key, is activated.

It should be appreciated that in the above description of exemplary embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment.

While some embodiments described herein include some, but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the disclosure, and form different embodiments, as would be understood by the skilled person. For example, in the following claims, any of the claimed embodiments can be used in any combination.

Thus, while certain embodiments have been described, it will be appreciated that other and further modifications may be made thereto without departing from the spirit of the disclosure, and it is intended to cover all such modifications, enhancements, and other implementations, which fall within the true spirit and scope of this disclosure. To the maximum extent permitted by law, the scope of this disclosure is to be determined by the broadest permissible interpretation of the following claims and shall not be restricted or limited by the foregoing detailed description.

While various implementations of the disclosure have been described, it will be readily apparent to the skilled person that many more implementations are possible within the scope of the disclosure.

Claims

CLAIMS1. A safety device for a CNC machine comprising: a handle portion movable between a first position and a second position; a first safety switch configured to be activated when the handle is in the first position and deactivated when the handle is in the second position; and a bumper bar configured to cut power to the CNC machine when the bumper bar determines application of pressure thereto.
2. A safety device for a CNC machine according to claim 1, wherein the handle portion comprises a substantially U-shaped or C-shaped structure and a pair of pivot points for mounting the handle portion to a CNC machine.
3. A safety device for a CNC machine according to claim 2, wherein the handle portion is operable to operatively engage a first part of a drive mechanism with a second part of drive mechanism when the handle portion is in the first position and to disengage the first part of the drive mechanism from with the second part of the drive mechanism when the handle portion is in the second position.
4. A safety device for a CNC machine according to claim 3, wherein the first part of the drive mechanism is a pinion, and the second part of the drive mechanism is a rack.
5. A safety device for a CNC machine according to any preceding claim, wherein the safety device is mounted to a gantry forming part of a CNC machine.
6. A safety device for a CNC machine according to any preceding claim, wherein the pair of pivot points of the handle portion are joined by an elongate member that is fixed to move around a same axis as the handle portion as the handle portion is moved between the first position and the second position.
7. A safety device for a CNC machine according to any preceding claim, wherein the first position of the handle portion is substantially parallel to a ground surface and the second position of the handle portion is angularly offset from the ground surface by between 25 to 45 degrees.
8. A safety device for a CNC machine according to claim 7, wherein the second position of the handle portion is angularly offset from the ground surface by 35 degrees.
9. A safety device for a CNC machine according to any preceding claim, wherein the handle portion comprises at least two independent handle portions, wherein movement of any one handle portion to the second position causes the CNC machine to be deactivated and wherein the CNC machine is only activated when all handle portions are moved to the first position
10. A safety device for a CNC machine according to any preceding claim, wherein the bumper bar extends substantially around the entirety of the handle portion, wherein the handle portion comprises a supporting part and an actuable part that is operable to engage a second safety switch when a force is applied against the actuable part.
11. A safety device for a CNC machine according to claim 10, wherein the second safety switch is configured to cut power to the CNC machine when the bumper bar is actuated.
12. A safety device for a CNC machine according to claim 10, wherein the second safety switch is configured to apply power to the CNC machine when the bumper bar is actuated.
13. A safety device according to any preceding claim, wherein the handle portion comprises at least two handle portions, each handle portion being associated with a respective first safety switch.
14. A safety device according to claim 13, wherein power is only applied to the CNC machine when all of the at least two handle portions is in the first position.
A CNC machine comprising a safety device according to any of claims 1 to 12.
16. A CNC machine according to claim 15 further comprising a gantry mounting the safety device, wherein the gantry comprises a head that is configured to move in a x-dimension along the gantry and control circuitry to drive at least one electric motor.
17. A CNC machine according to claim 15 or claim 16, wherein the gantry comprises a pair of pinions, one at each end of the gantry, and the CNC machine further comprises a bed for receiving a work piece, wherein the bed comprises a pair of parallel racks, each rack being arranged and configured to receive a respective one of the pinions of the gantry, and wherein the gantry is configured to be selectively electrically connected to the bed and disconnected and removed from the bed for stowage and transport.
18. A CNC machine according to claim 17, wherein the bed further comprises a plurality of support legs, each support leg being configured to fold substantially flat against an underside of the bed for stowage and transport.
19. A CNC machine according to claim 18, further comprising a gas strut between each support leg and the underside of the base, the gas strut being configured to hold the respective support leg in a deployed configuration.
20. A CNC machine according to any of claims 16 to 19 further comprising a pair of guide rails and a pair of guides, wherein each of the pair of guides is configured to slide along a respective guide rail and comprises a first part of a locking interface for engagement with a support block of the gantry, wherein the support block engages the guide when the handle is in the second position and the support block is spaced apart from the guide when the handle is in the first position.
21. A CNC machine according to claim 20, wherein the support block further comprises a second part of the locking interface in the form of a locking pin that projects downwardly and engages the first part of the locking interface when the handle is in the second position.