EP3576913A1

EP3576913A1 - Circular saw, in particular hand-held circular saw

Info

Publication number: EP3576913A1
Application number: EP18700208.4A
Authority: EP
Inventors: Juergen Wiker; Thomas Ziegler; Michael Wall; Daniel Dennis; Torsten Riek
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-01-31
Filing date: 2018-01-10
Publication date: 2019-12-11
Anticipated expiration: 2038-01-10
Also published as: CN110234478B; WO2018141512A1; DE102017201493A1; US10967537B2; US20190381688A1; EP3576913B1; CN110234478A

Abstract

The invention relates to a circular saw (100), in particular a hand-held circular saw, having a housing (110) and a drive unit, at least some sections of which are arranged in the housing (110) and with which a tool holder (140) for an exchangeable saw blade (130) is associated, the drive unit (710) being designed to rotationally drive the exchangeable saw blade (130) about an associated axis of rotation (140). In said circular saw a blade guard (150) is associated with the exchangeable saw blade (130), which blade guard is mounted in the housing (110) for rotation about the associated axis of rotation (140) and which extends around a cutting point (132) of the exchangeable saw blade (130) at least during a sawing operation in such a way that contact with the cutting point (132) can be at least substantially prevented.

Description

Description title

Circular saw, especially circular saw State of the art

The present invention relates to a circular saw, in particular a circular saw, with a housing and an at least partially arranged in the housing drive unit, which is associated with a tool holder for a replaceable blade, wherein the drive unit is designed to rotate the exchangeable saw blade about an associated axis of rotation.

From the prior art, such, designed as a circular saw circular saw is known, which has a housing and a sectionally arranged in the housing drive unit. In this case, the drive unit is associated with a tool holder for a replaceable saw blade and the drive unit is designed for the rotary drive of the replaceable saw blade about an associated axis of rotation. To protect a user of the circular saw from injury due to contact with the cutting edge, the circular saw has a pendulum protection hood. This swing hood encloses the saw blade and is rotatably mounted about a saw blade center. During a sawing process, the pendulum protection hood is loaded into the housing of the circular saw, so that the saw blade is exposed and thus injury may occur due to contact of the user with the cutting edge.

Disclosure of the invention

The present invention provides a circular saw, in particular a circular saw, with a housing and an at least partially arranged in the housing drive unit, which is associated with a tool holder for a replaceable blade. The drive unit is for turning drive the replaceable saw blade formed around an associated axis of rotation. The replaceable saw blade is associated with a protective wedge which is rotatably mounted in the housing about the associated axis of rotation and at least during a sawing process encloses a cutting edge of the exchangeable saw blade such that contact of the cutting edge can be at least substantially prevented.

The invention thus makes it possible to provide a circular saw, in particular a circular saw, in which a corresponding risk of injury due to contact with the cutting edge of the saw blade can be at least largely reduced by the protective wedge even during a sawing operation. Thus, the provision of a safe and reliable circular saw can be made possible.

The protective wedge preferably has a thickness which corresponds at most to a thickness of the exchangeable saw blade. Thus, the protective wedge can be performed during a sawing operation in a saw groove formed by the saw blade and thus enclose the saw blade during a sawing operation and thereby at least approximately prevent contact with the blade of the saw blade.

Preferably, the protective wedge is spring-loaded for enclosing the cutting edge of the replaceable saw blade. Thus, an arrangement of the protective wedge can be made possible, in which the cutting edge of the saw blade can always be maximally enclosed.

According to one embodiment, the protective wedge is spring-loaded such that the cutting edge of the exchangeable saw blade is maximally enclosed. Thus, a contact with the cutting edge can be reliably and reliably at least substantially prevented even during a sawing operation.

The protective wedge is preferably rotatably mounted on an end of the housing facing away from a working area of the circular saw. Thus, a simple and uncomplicated maximum enclosure of the saw blade can be made possible. The protective wedge is preferably designed in the manner of a semicircular ring. Thus, a suitable protective wedge can be provided in a simple manner, which can be arranged pivotably about the axis of rotation of the drive unit.

According to one embodiment, the protective wedge releases the exchangeable saw blade in a maximum angle range of 90 ° during a sawing process. Thus, a maximum enclosure of the saw blade can be made possible with maximum depth of cut.

Preferably, a touch sensor is associated with the protective wedge. Thus, a contact protection in the range of a working area of the circular saw can be made safe and uncomplicated.

According to one embodiment, a safety device is provided, which is designed to enable safe operation of the circular saw. In this case, the safety device may be provided in addition to the protective wedge, or alternatively. Thus, the provision of a safe and reliable circular saw can be made possible in a simple manner.

The safety device preferably has a coupling for decoupling the drive unit from the exchangeable saw blade. Thus, upon detection of a touch, a rapid braking of the saw blade and a comparatively short braking time can be made possible.

The safety device preferably has a saw blade brake. Thus, in a simple manner, a braking of the saw blade in a detection of a touch can be made possible.

Preferably, the saw blade brake is formed in the manner of a disc brake with at least one brake disc, or in the manner of a pyro-brake with a pyro and a blocking element. Thus, a suitable saw blade brake can be provided easily and simply.

According to one embodiment, the safety device has a linear actuator for linear displacement of the exchangeable saw blade. Thus, can The saw blade are subjected to a detection of a contact in the housing, so that the contact can be quickly prevented.

Brief description of the drawings

The invention is explained in more detail in the following description with reference to exemplary embodiments illustrated in the drawings. Show it:

1 is a side view of a power tool with a protective wedge in a protective position,

Fig. 2 is a side view of the power tool of FIG. 1 with the

Protective wedge in a maximum open position, Fig. 3 is a side view of the power tool of FIG. 2 with the

Protective wedge in a largely closed position,

4 is a side view of the hand tool of Fig. 1 to Fig. 3 in a sawing operation in a workpiece,

5 is a side view of the power tool of FIG. 4 during a sawing operation, with an application of the protective wedge,

6 shows a side view of the hand tool of FIG. 4 and FIG. 5 during a sawing process in a workpiece, with the protective wedge in a maximally open position, FIG.

7 is a sectional view of the hand tool of FIGS. 1 to 6 with a saw blade brake according to one embodiment,

8 is a sectional view of the hand tool of Fig. 1 to Fig. 7 with a linear actuator,

9 is a sectional view of the hand tool of FIGS. 1 to 7, with the linear actuator of FIG. 8, seen in the direction of arrows IX of FIG. 8, and FIG 10 shows a perspective view of a saw blade brake associated with the hand tool of FIGS. 1 to 7 according to a further embodiment.

Description of the embodiments

Fig. 1 shows a trained example of a circular saw hand tool 100 with a housing 1 10, which preferably forms a handle 1 12. The circular saw 100 is preferably assigned a drive unit (710 in FIG. 7), which is arranged at least in sections in the housing 110. The drive unit (710 in FIG. 7) preferably serves to drive a tool receptacle 140 for an exchangeable saw blade 130. The drive unit (710 in FIG. 7) is designed in particular for rotationally driving the replaceable saw blade 130 about an associated rotation axis 142. The saw blade 130 is preferably formed as a circular saw blade with a cutting edge 132.

Preferably, the circular saw 100 is connected to the network-dependent power supply mechanically and electrically connected to a power line 107, but could be lent additional or alternatively to the grid-independent power supply with a battery pack. Illustratively, the circular saw 100 is formed in the manner of a circular saw and is therefore hereinafter also referred to as the "circular saw 100", but can also be designed as a table saw, dip saw or any other power tool with a saw blade.

Preferably, the circular saw 100, preferably the housing 1 10, a first and second end 1 1 1, 1 13, wherein the circular saw 100 is provided for sawing in a direction of operation 101. In this case, a corresponding working area 15 is preferably formed at the first end 11 1 or in the working direction 101 in front of the saw blade 130. In addition, the circular saw 100 is preferably provided with a guide plate 120, which can be guided, for example, on an upper side (202 in FIG. 2) of a workpiece to be machined (210 in FIG. 2). In this case, the guide plate 120 has an underside 121 which is illustratively remote from the drive unit (710 in FIG. 7) and with which the circular saw 100 can be moved on the upper side (202 in FIG. 2) of the workpiece to be machined (210 in FIG ) can be performed. Preferably, the saw blade 130 is associated with a protective wedge 150, which is preferably rotatably mounted about the associated axis of rotation 140 in or on the housing 1 10. In this case, the protective wedge 150 preferably encloses the cutting edge 132 of the saw blade 130, at least during a sawing process, such that a contact of the cutting edge 132 by a user of the portable circular saw 100 is at least substantially prevented. In FIG. 1, the cutting edge 132 is illustratively completely surrounded by the protective wedge 150, so that a contact of the cutting edge 132 in the region of the first end 1 1 1, the second end 1 13 and / or by an example of the underside 121 of the guide plate 120 facing Side, or illustrativ in the direction of arrows 102, 103, 104, is prevented.

Preferably, the protective wedge 150 is rotatably mounted at the first end 1 1 1 or at the end 1 13 of the housing 1 10 facing away from the working area 15. Preferably, the protective wedge 150 is designed in the manner of a semicircular ring 152. The guard wedge 150 is preferably spring biased to enclose the cutting edge 132 of the saw blade 130. In this case, the protective wedge 150 is preferably spring-loaded in such a way that the cutting edge 132 is maximally enclosed. In this case, the protective wedge 150 preferably has a thickness which corresponds at most to one thickness of the saw blade 130, so that the protective wedge 150 can be arranged or guided during a sawing process in a corresponding saw groove formed by the saw blade 130. During a sawing operation, the protective wedge 150 preferably releases the saw blade 130 by a maximum of an angle range of 90 °. This is preferably done during a sawing process with maximum cutting depth of the saw blade 130.

In addition, the circular saw 100 may preferably also include an optional swing guard. A corresponding swing guard is well known in the art, which is why, for the sake of simplicity and brevity, the description refers to a detailed description of the optional

Swing protection hood is omitted.

FIG. 2 shows the circular saw 100 of FIG. 1 with the protective wedge 150 in an open position, in which the protective wedge 150 only partially encloses the saw blade 130. By way of example, FIG. 2 illustrates a position which preferably corresponds to a maximum open or retracted position of the protective wedge 150 equivalent. It should be noted, however, that depending on the application, the maximum open position of the protective wedge 150 can also release a larger area of the saw blade 130, for example in the case of a dip saw, in which the protective wedge 150 can be screwed in completely.

Illustratively, in FIG. 2, the portable circular saw 100 is arranged outside a workpiece 210. The workpiece 210 is formed in FIG. 2, for example, rectangular and has a top and bottom 202, 201, wherein the circular saw 100 is illustratively arranged above the top 202. Such an arrangement of the circular saw 100 above the workpiece 210 may be present, for example, before or after a sawing operation or during a sawing process after a so-called "kickback" in which the circular saw 100 is catapulted out of the workpiece 210. FIG. 3 shows the circular saw 100 of FIG 2, in which the cutting edge 132 of the saw blade 130 is enclosed or almost completely enclosed by the spring-loaded protective wedge 150 in comparison with FIG 1 1 1 facing region 302 only in an angular range of approximately 25 ° free., Since the spring-loaded guard wedge 150 preferably has a comparatively small inertia, so a relatively fast enclosing the cutting edge 132 can be made possible.

4 shows the circular saw 100 of FIGS. 1 to 3 in a preferred working position during a sawing process in the workpiece 210, in which the guide plate 120 rests with its underside 121 on the upper side 202 of the workpiece 210 and is guided. In this case, the protective wedge 150 encloses the cutting edge 132 of the saw blade 130 in such a way that contact of a user with the saw blade 130 or the cutting edge 132 in the region of the underside 204 of the workpiece 210 or in the direction of an arrow 402 is effectively prevented.

FIG. 5 shows the circular saw 100 of FIG. 4 in the working position, in the example of an application from the first end 1 1 1 in the direction of the second end 1 13 or a loading of the protective wedge 150 into the housing 1 10 or in the direction of an arrow 502 takes place. Such an application can, for example, be exercised by a body part of a user, eg his hand. the. In order to protect a user in the event of such action, a contact sensor system 510 is preferably associated with the protective wedge 150.

Illustratively, in Fig. 5, the touch sensor 510 is disposed in the housing 1 10, but can also directly on the protective wedge 150 or any other place the

Circular saw 100 may be arranged. Preferably, the touch sensor system 510 detects contact between the protective wedge 150 and another object, such as the hand of a user of the circular saw 100. In addition, the touch sensor system 510 may also detect the guard 150 with a protective device, e.g. a glove or the like detectable by the touch sensor 510. In this case, the touch sensor system 510 is preferably designed to trigger a mechanism upon detection, which preferably blocks the protective wedge 150.

FIG. 6 shows the circular saw 100 of FIGS. 1 to 5 in the working position at a maximum depth of cut. In this case, Fig. 6 illustrates a section line 610 of the saw blade 130 in the workpiece 210. Preferably, the protective wedge 150 is arranged at maximum depth of cut in its preferred maximum open position, or preferably by an angle α of preferably maximally 90 ° released. As described above, the maximum open position of the protective wedge 150 may also be less than or greater than 90 °.

FIG. 7 shows the exemplary circular saw 100 of FIGS. 1 to 6 and illustrates a drive unit 710 of the portable circular saw 100. The drive unit

710, a drive motor 712 is preferably associated with a drive shaft 716. The drive shaft 714 is designed to drive an output shaft 716 associated with the tool holder 140. In this case, the saw blade 130 is preferably detachably arranged on the tool receptacle 140 with a fastening means 718. Preferably, the fastener 718 is as

Screw formed.

According to one embodiment, the circular saw 100 has a safety device 750, which is designed to enable safe operation of the circular saw 100. The safety device 750 is preferably associated with the touch sensor system 510 of FIG. 5, wherein the touch sensor system 510 in this case, it is preferably designed to activate the safety device 750 when a touch is detected, for example by a body part of a user of the portable circular saw 100. It should be noted, however, that the safety device 750 need not necessarily be associated with the touch sensor 510 of FIG. 5, but may be used instead of the protection wedge 150 and the touch sensor 510 of FIG. 5. In addition, the safety device 750 can also be assigned a separate touch sensor system, which can be arranged, for example, on the saw blade 130 or assigned to it. Similarly, each of the embodiments of the security device 750 described below may be used separately or in combination with one or more other embodiments of the security device 750.

The safety device 750 acc. FIG. 7 preferably has a brake 760 configured as a saw blade brake for braking the saw blade 130, which is preferably triggered upon activation of the safety device 750. In this case, the saw blade brake 760 is preferably designed in the manner of a disc brake with at least one, illustratively two brake discs 736, 738. In this case, the two brake disks 736, 738 are arranged, for example, on the side of the saw blade 130, wherein the brake disk 736 in FIG. 7 is arranged illustratively to the right of the saw blade 130 and the brake disk 738 is arranged illustratively to the left of the saw blade 130. Preferably, the two brake discs 736, 738 are each spring-loaded via a spring element 732, 734. In this case, a mechanism is preferably provided which is designed to hold back the brake disks 736, 738 and / or the spring elements 732, 734 during a sawing operation, so that the saw blade 130 can rotate unhindered or unrestrained. The mechanism and / or the spring elements 732, 734 preferably have a hook element for retaining the brake disks 736, 738. Upon activation of the saw blade brake 760 by the touch sensor 510, or in the event of contact, an actuator preferably releases the hook element and the spring elements 732, 734 act on the brake disks 736, 738 on the saw blade 130. It should be noted that the embodiment of FIG Mechanism for triggering the saw blade brake 760 only exemplary character and not to be seen as a limitation of the present invention. Thus, the mechanism can be designed in different ways, for example as a combination with a spring element and a fuse wire. In this case, by way of example, the spring element can be retained during a sawing process by a wire, which is burned out upon detection of a contact. Alternatively, the fusible wire may also be formed in the manner of a wire from a shape memory alloy.

However, the present invention is not limited to a blade brake 760 that acts directly on the saw blade 130. For example, a braking element, e.g. a brake disc, directly to the tool holder 140 attack. Preferably, the saw blade brake 760 is arranged as far as possible at the end of the drive unit 710, so that as few rotating parts must be braked to bring the saw blade 130 to a halt. Thereby, a braking time of the saw blade 130 can be shortened.

In addition, the brake 760 may alternatively be designed as a wrap spring brake and / or wedge brake. In this case, a wedge brake has at least one wedge, which brakes the saw blade 130. In this case, self-reinforcement by the at least one wedge and a rotational movement of the saw blade 130 can be achieved. As a result, a comparatively high braking force can be achieved with a comparatively small spring force. Preferably, the brake can also be designed as an exchangeable module, whereby a simple handling of the saw blade brake 760 can be made possible. Thus, for example, a wedge brake, which jams at a comparatively high force, whereby the at least one wedge jammed between the saw blade 130 and a guide of the wedge, are exchanged easily and simply and are preferably reset or disconnected from the outside. Furthermore, the safety device 750 preferably has a coupling 720 for decoupling the drive unit 710 from the saw blade 130, so that only the saw blade 130 has to be braked. Thus, the blade brake 760 preferably only needs to operate against a relatively low torque of the drive motor 712 and only has to apply a moment to overcome the inertia of the circular saw 100 to decelerate the circular saw 100 and the saw blade 130, respectively. This can be a comparatively short Braking time can be realized. Preferably, the coupling 720 is associated with the tool holder 140, so that only a necessary moment for a normal operation or for a sawing operation is transmitted to the saw blade 130. It should be noted, however, that the configuration of the tool holder 140 with the coupling 720 has merely exemplary character and is not to be seen as limiting the invention. Thus, the coupling 720 may also be formed as a separate coupling, which is preferably arranged in the region of the saw blade 130. In this case, the separate clutch is preferably designed analogously to the clutch 720 to decouple the saw blade 130 from the drive unit 710. Preferably, a relevant inertia to be braked should be reduced in such a way that preferably as few parts as possible, particularly preferably only the saw blade 130, can be braked as quickly as possible.

FIG. 8 shows the circular saw 100 of FIGS. 1 to 7 with the safety device 750, which, as an alternative or in addition, is assigned a linear actuator 810. As described above, the safety device 750 is preferably associated with the touch sensor system 510 of FIG. 5, wherein the touch sensor system 510 is preferably configured to detect a touch, e.g. by a body part of a user of the portable circular saw 100 to activate the safety device 750. In this case, the safety device 750 activates the linear actuator 810, which is designed to move the saw blade 130 linearly or to move.

Preferably, the linear actuator 810 has a coupling 820, which is designed to decouple the drive unit 710 of FIG. 7 from the saw blade 130. Upon activation of the safety device 750, the clutch 820 is released with the saw blade 130 decoupled from the drive unit 710 and with the linear actuator 810 linearly preferring the saw blade 130 into the housing

1 10 of the circular saw 100 is acted upon or displaced. Thus, especially in the case of a touch by a body part of a user of the portable circular saw 100, a corresponding contact is lifted very quickly, so that at most only comparatively small incisions or injuries to the body part can occur. The clutch 820 is preferably disposed between the output shaft 716 and an intermediate shaft 830. During a sawing process, the clutch 820 is preferably spring-loaded against the intermediate shaft 830 via at least one spring element 825. In this case, a torque and a rotational speed of the output shaft 716 are preferably transmitted to the intermediate shaft 830 via the coupling 820 and to the saw blade 130 through the intermediate shaft 830. The intermediate shaft 830 is preferably mounted in a bearing housing 850.

Preferably, the coupling 820 has a cylindrical main body 822, which for example has a passage opening 829 for arrangement on the output shaft 716 and / or the intermediate shaft 830. On its side facing the intermediate shaft 830, the main body 822 preferably has a coupling section 827. Illustratively and by way of example, the coupling portion 827 is formed as a slope.

Upon activation of the safety device 750, the clutch 820 is preferably first decoupled. In this case, a release element 840 acted upon by at least one spring element 849 is preferably released. By the spring element 849, the trigger element 840 is applied illustratively upwards. Preferably, the spring element 849 is arranged on the guide plate 120 of the circular saw 100. The triggering element 840 is preferably assigned a surface 845 corresponding to the coupling section 827. Due to the illustratively vertical movement of the trigger element 840, the surface 845 preferably urges the clutch 820 against the at least one spring element 825 or illustratively to the left. Thus, the clutch 820 is decoupled and the output shaft 716 is disconnected from the intermediate shaft 830. In this case, an upper edge 842 of the triggering element 840 facing the bearing housing 850 preferably acts on the bearing housing 850 with the intermediate shaft 830 in an upward or linear upward direction.

FIG. 9 shows the circular saw 810 with the linear actuator 810. FIG. 9 illustrates the linear actuator 810, which is preferably assigned two guide rails 922, 924, on which the trigger element 840 is arranged to be linearly movable. Preferably, the two guide rails 922, 924 on the housing 1 10 are arranged. For linear movement of the intermediate shaft 830 has the

Bearing housing 850 preferably two lateral guide elements 912, 914, which are preferably mounted on the guide rails 922, 924. In addition, FIG. 9 illustrates the triggering element 840 acted upon by at least one spring element, illustratively via two spring elements 849, which is designed to act linearly on or move the bearing housing 850 in the case of a decoupled coupling 820.

FIG. 10 shows an alternative brake 1060 associated with the safety device 750. The brake 1060 is preferably designed as a saw blade brake, wherein the saw blade brake 1060 is preferably designed in the manner of a pyro brake with a pyro 1040 and a blocking element 1042. For this purpose, the saw blade 130 preferably has a plurality 1030 of recesses 132, 134 in the circumferential direction, into which the blocking element 1042 is abruptly moved in the direction of an arrow 1002 when the safety device 750 or the pyro brake 1060 is activated. In this case, the blocking element 1042 can also be acted upon by a spring element, or by a combination of a spring element and the Pyro 1040.

Claims

claims

1 . Circular saw (100), in particular circular saw, with a housing (1 10) and an at least partially in the housing (1 10) arranged drive unit (710) associated with a tool holder (140) for a replaceable saw blade (130), wherein the Drive unit (710) for the rotary drive of the replaceable saw blade (130) about an associated axis of rotation (140) is formed, characterized in that the replaceable blade (130) is associated with a protective wedge (150) which is rotatable about the associated axis of rotation (140) is stored in the housing (1 10) and a cutting edge (132) of the replaceable saw blade (130) at least during a sawing process encloses such that a contact of the cutting edge (132) can be at least substantially prevented.

2. Circular saw according to claim 1, characterized in that the protective wedge (150) has a thickness which corresponds at most to a thickness of the exchangeable saw blade (130).

3. Circular saw according to claim 1 or 2, characterized in that the protective wedge (150) for enclosing the cutting edge (132) of the replaceable saw blade (130) is spring-loaded.

4. Circular saw according to claim 3, characterized in that the protective wedge (150) is spring-loaded in such a way that the cutting edge (132) of the exchangeable saw blade (130) is maximally enclosed.

Circular saw according to one of the preceding claims, characterized in that the protective wedge (150) on one of a working area (1 15) of the circular saw (100) facing away from the end (1 13) of the housing (1 10) is rotatably mounted.

6. Circular saw according to one of the preceding claims, characterized in that the protective wedge (150) in the manner of a semi-circular ring (152) is formed.

7. Circular saw according to one of the preceding claims, characterized in that the protective wedge (150) releases the exchangeable saw blade (130) during a sawing process in a maximum angle range of 90 °.

8. Circular saw according to one of the preceding claims, characterized in that the protective wedge (150) is associated with a touch sensor (510).

9. Circular saw according to one of the preceding claims, characterized in that a safety device (750) is provided which is adapted to enable safe operation of the circular saw (100).

10. Circular saw according to claim 9, characterized in that the safety device (750) has a coupling (720, 820) for decoupling the drive unit (710) from the exchangeable saw blade (130).

1 1. Circular saw according to claim 9 or 10, characterized in that the safety device (750) has a saw blade brake (760; 1060).

12. Circular saw according to claim 1 1, characterized in that the saw blade brake (760; 1060) in the manner of a disc brake with at least one brake disc (736, 738) is formed, or in the manner of a Pyrobremse (1060) with a Pyro (1040) and a blocking element (1042).

13. Circular saw according to one of claims 9 to 12, characterized in that the safety device (750) has a linear actuator (810) for the linear displacement of the exchangeable saw blade (130).